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Alders are nitrogen (N)-fixing riparian trees that promote leaf litter decomposition in streams through their high-nutrient leaf litter inputs. While alders are widespread across Europe, their populations are at risk due to infection by the oomycete Phytophthora ×alni, which causes alder dieback. Moreover, alder death opens a space for the establishment of an aggressive N-fixing invasive species, the black locust (Robinia pseudoacacia). Shifts from riparian vegetation containing healthy to infected alder and, eventually, alder loss and replacement with black locust may alter the key process of leaf litter decomposition and associated microbial decomposer assemblages. We examined this question in a microcosm experiment comparing three types of leaf litter mixtures: one representing an original riparian forest composed of healthy alder (Alnus lusitanica), ash (Fraxinus angustifolia), and poplar (Populus nigra); one with the same species composition where alder had been infected by P. ×alni; and one where alder had been replaced with black locust. The experiment lasted six weeks, and every two weeks, microbially driven decomposition, fungal biomass, reproduction, and assemblage structure were measured. Decomposition was highest in mixtures with infected alder and lowest in mixtures with black locust, reflecting differences in leaf nutrient concentrations. Mixtures with alder showed distinct fungal assemblages and higher sporulation rates than mixtures with black locust. Our results indicate that alder loss and its replacement with black locust may alter key stream ecosystem processes and assemblages, with important changes already occurring during alder infection. This highlights the importance of maintaining heathy riparian forests to preserve proper stream ecosystem functioning. [ABSTRACT FROM AUTHOR]

This article highlights the evolution, birth and legacy of the world's first neonatal surgical unit established at Alder Hey Children's Hospital Liverpool in 1953. Peter Paul Rickham, a creative pioneering and innovative surgeon, is credited here as a major driving force that helped shape and progress the modern day development of neonatal surgery. Rickham's vision was realised by studying neonatal surgical disorders and the mortality rate of congenital anomalies in Mersey Region while working as a young senior registrar with Isabella Forshall. Rickham defined the extent of the problem(s) and set to work as a newly appointed consultant a vision for improving outcomes with the creation and establishment of a preeminent world leading neonatal surgical unit. Surgeons from all over the world travelled to work, learn and train with Rickham and the paediatric surgical staff team at Alder Hey in the subsequent years to follow. Neonatal anaesthesia greatly advanced by Jackson Rees a colleague working in Liverpool with Rickham allowed huge success to flourish—'the impossible became possible'. The neonatal surgical unit in Liverpool became the benchmark and prototype for units to develop around the world immediately resulting in improvement in the survival of newborn infants undergoing surgery from 22 to 74%. Rickham's contributions to neonatal and paediatric surgery are truly remarkable. Alder Hey hosts an international symposium and special dinner with Rickham family members as VIP guests in its calendar of events. A symposium highlight is the Rickham Lecture with the PPR Gold Medal awarded to an international renowned leader in the field of paediatric surgery and the surgical sciences. [ABSTRACT FROM AUTHOR]

Understanding of the process of hydraulic redistribution in agricultural landscapes is important for informing agroforestry design and agricultural management. The measurement of hydraulic lift and redistribution in the field is still a challenge. Due to the robustness of stable isotope analysis, we hypothesized that the measurement and analysis of the natural abundance of stable isotopes δ2H and δ1⁸O, in the twigs of agroforestry trees, stems of wheat intercrop, rain, and soil water coupled to an isotopic mixing modeling by IsoSource supplemented with other physiological crop parameters, would estimate the extent of hydraulic redistribution in intercropping, and inform the design of an agroforestry system. There are still many plant species that have not been investigated for their potential hydraulic redistribution yet, and Alnus acuminata is among them, therefore this study aimed to contribute to filling that gap. The field experiment was conducted in an Andic soil of the northern Rwanda highlands to address the extent of water efflux redistribution from tree roots of Alnus acuminata to the wheat intercrop across bench terraces. The study involved the measurement of the natural abundance of stable isotopes δ2H, and δ1⁸O of the tree twigs, soil and wheat stems at distances of 1, 3, 5, and 7 m from the tree lines of Alnus acuminata, and of rainwater. The isotopic mixing modeling was supplemented by measuring both specific leaf area (SLA) and carbon discrimination (Δ13C) in the wheat leaf. We noted a significant (p < 0.01) gradient in the depletion of wheat xylem water δ2H and δ18O signatures moving further away from the tree lines. Based on the wheat value of δ2H, the isoSource indicated that the trees may have contributed the wheat water up to 64.3 ± 2.6% at 5 m from the trees, and the values of both the SLA (cm2 g–1) and ∆13C (‰) of wheat leaf indicated the water use efficiency of wheat significantly improved around the trees up to 3 m away from the trees with 140.10 ± 3.74 cm2 g–1, 149.56 ± 3.43 cm2 g–1 and 20.6 ± 0.1‰, 20.8 ± 0.1‰ at 1 m and 3 m for SLA and ∆13C respectively. We concluded that Alnus acuminata exhibits significant hydraulic redistribution in the field. [ABSTRACT FROM AUTHOR]

The N2-fixing trees Alnus spp. have been widely encroaching into boreal peatlands, but the nutrient responses of native vascular plants remain unclear. Here, we compared nutrient concentrations and isotope signal of six common plants (Betula fruticosa, Salix rosmarinifolia, Vaccinium uliginosum, Rhododendron tomentosum, Chamaedaphne calyculata, and Eriophorum vaginatum) between Alnus hirsuta island and open peatland and assessed plant nutrient responses to A. hirsuta encroachment in boreal peatlands. Alnus hirsuta encroachment increased nitrogen (N) concentration of leaf, branch, and stem. Despite no significant interspecific difference in branch and stem, the increment magnitude of leaf N concentration varied among species, with greatest magnitude for R. tomentosum (55.1% ± 40.7%) and lowest for E. vaginatum (9.80% ± 4.40%) and B. fruticosa (18.4% ± 10.7%). Except for E. vaginatum, the significant increase in δ15N occurred for all organs of shrubs, with interspecific differences in change of leaf δ15N. According to the mass balance equation involving leaf δ15N, R. tomentosum and E. vaginatum, respectively, obtained highest (40.5% ± 19.8%) and lowest proportions (–14.0% ± 30.5%) of N from A. hirsuta. Moreover, the increment magnitudes of leaf N concentration showed a positive linear relationship with the proportion of N from A. hirsuta. In addition, A. hirsuta encroachment reduced leaf phosphorus (P) concentration of deciduous shrubs (i.e., B. fruticosa, S. rosmarinifolia, and V. uliginosum), thus increasing N:P ratio. These findings indicate that Alnus encroachment improves native plant N status and selectively intensifies P limitation of native deciduous shrubs, and highlight that the N acquisition from the symbiotic N2-fixing system regulates plant N responses in boreal peatlands. [ABSTRACT FROM AUTHOR]

The dataset presents a 43 year-long reanalysis of pollen seasons for three major allergenic genera of trees in Europe: alder (Alnus), birch (Betula), and olive (Olea). Driven by the meteorological reanalysis ERA5, the atmospheric composition model SILAM predicted the flowering period and calculated the Europe-wide dispersion pattern of pollen for the years 1980–2022. The model applied an extended 4-dimensional variational data assimilation of in-situ observations of aerobiological networks in 34 European countries to reproduce the inter-annual variability and trends of pollen production and distribution. The control variable of the assimilation procedure was the total pollen release during each flowering season, implemented as an annual correction factor to the mean pollen production. The dataset was designed as an input to studies on climate-induced and anthropogenically driven changes in the European vegetation, biodiversity monitoring, bioaerosol modelling and assessment, as well as, in combination with intra-seasonal observations, for health-related applications. [ABSTRACT FROM AUTHOR]

In the socio-ecological landscapes of tropical mountains, including the highly diverse Eastern Himalaya, fragments of natural forests have been traditionally managed as part of different agriculture systems. Recent studies have recognized their role as important biodiversity repositories outside protected areas. However, basic information on forest structure and composition of these forests outside protected areas is still limited in the Himalaya. In the current study, diversity, structure, composition, and regeneration status of non-protected forests were studied across 15 spatially different sites in the socio-ecological landscapes of Darjeeling-Sikkim, Eastern Himalaya, across an approximate elevation range of 500-2300 m above sea level. Quadrats (20 m × 5 m) were used to enumerate woody species in the study area. Enumeration of 156 quadrats (= 1.56 ha) resulted in a total of 249 woody species, of which species such as Schima wallichii, Alnus nepalensis, and Engelhardtia spicata were found to dominate the existing stand of trees. The vegetation structure of these forests was found to be almost comparable with that of protected forests, as assessed by prior studies in the same landscape. Species composition of woody plants in the study area were found to be primarily influenced by elevation. Assessment of regeneration patterns found the forests to have a high regeneration potential, however, the most dominant tree species of the area had relatively fewer saplings, indicating probable replacement of localized species of large trees by disturbance-adapted species. The current study adds to the literature on the structure and composition of non-protected forests in the tropical mountains. [ABSTRACT FROM AUTHOR]

The results of the study obtained for spores and pollen from the subfossil spectra of samples from the Bykovsky Peninsula (northern Yakutia) are presented in order to compare them with the current vegetation composition, to consider the major cryogenic disturbances of palynological remains, and to analyze their cryogenic destruction processes. The abundant alien pollen of Betula sect. Nanae and Alnus in the spectra is due to open landscapes, relatively low pollen productivity, and the transition of herbs and shrubs prevailing in the local phytocenoses to a vegetative propagation in severe climatic conditions. The selective role of cryogenesis in the spore–pollen spectra formation is related to repeated sediment thawing and freezing cycles, resulting in physical damage (ruptures and cracks) in palynological remains. The results of research contribute to the study of the methodological aspects of palynotaphonomy in cryolithic zone sediments. They can be used to reconstruct the Neopleistocene landscapes and vegetation and to study cryopreservation of fossil living organisms and their diversity in the permafrost areas. [ABSTRACT FROM AUTHOR]

We study the long time behaviour of a Brownian particle evolving in a dynamic random environment. Recently, Cannizzaro et al. (Ann Probab 50(6):2475–2498, 2022) proved sharp log -super diffusive bounds for a Brownian particle in the curl of (a regularisation of) the 2-D Gaussian Free Field (GFF) ω ̲ . We consider a one parameter family of Markovian and Gaussian dynamic environments which are reversible with respect to the law of ω ̲ . Adapting their method, we show that if s ≥ 1 , with s = 1 corresponding to the standard stochastic heat equation, then the particle stays log -super diffusive, whereas if s < 1 , corresponding to a fractional heat equation, then the particle becomes diffusive. In fact, for s < 1 , we show that this is a particular case of Komorowski and Olla (J Funct Anal 197(1):179–211, 2003), which yields an invariance principle through a Sector Condition result. Our main results agree with the Alder–Wainwright scaling argument (see Alder and Wainwright in Phys Rev Lett 18:988–990, 1967; Alder and Wainwright in Phys Rev A 1:18–21, 1970; Alder et al. in Phys Rev A 4:233–237, 1971; Forster et al. in Phys Rev A 16:732–749, 1977) used originally in Tóth and Valkó (J Stat Phys 147(1):113–131, 2012) to predict the log -corrections to diffusivity. We also provide examples which display log a -super diffusive behaviour for a ∈ (0 , 1 / 2 ] . [ABSTRACT FROM AUTHOR]

Alnus glutinosa is an actinorhizal plant that fixes N via actinomycetes. Compared to other trees, A. glutinosa is more resistant to environmental stress and able to uptake soil nutrients more easily. Alnus glutinosa grows well not only in natural stands but also in degraded environment or soil in need of restoration. Changes in the contents of selected macro-, micro-, and non-nutrient elements in the leaves of A. glutinosa during the vegetation season were monitored in the Ore Mountains (Czech Republic), an area affected by extreme air pollution in the past. Decreased foliar content of N, P, K, and Cu, and increased content of Ca, Mn, Zn, and Al were observed; the content of other elements (S, Mg, Pb, and Cd) varied during the growing season or remained constant. From the viewpoint of nutrition, the content of N, S, Ca, and Mg macroelements was adequate; concentrations of P and K were low. Excessive amounts of Mn and Zn were measured, and the level of Cu was good. Non-nutrient elements Pb and Cd were present at the background level, and the level of Al was high. N/P, N/Ca, N/Mg, and Ca/Mg ratios were balanced, S/N value showed the lack of S, and N/K ratio indicated low content of K, which caused also suboptimal K/Ca and K/Mg values. The P/Al ratio varied from balanced to lower values. The content of individual elements and monitored changes were influenced by the amount of elements in the soil, moisture conditions, foliage phenology, and altitude. [ABSTRACT FROM AUTHOR]

Alnus (Alnus acuminata Kunth) has been widely promoted under climate change mitigation and adaptation programs in the East African highlands. However, information is lacking on the impact of pruning management and green manure (GM) application on soil health and the productivity of associated crops. Using a large suit of soil quality indicators, crop growth and yield measurements, this study identified appropriate combinations of alnus pruning levels and GM application for sustainable intensification of potato (Solanum tuberosum) and wheat (Triticum aestivum) production in alley cropping with Alnus. This study compared six treatments, namely, (1) sole crops of potato or wheat (control), (2) sole crop + GM, (3) 75% pruning, (4) 75% pruning + GM, (5) 90% pruning and (6) 90% pruning + GM. In all treatments potato and wheat were grown in rotation. The best treatments were the 75% pruning + GM and 90% pruning + GM, which significantly differed from the control in soil pH, soil organic carbon (SOC), total nitrogen (TN), total phosphorus (P), exchangeable calcium (Ca) contents, the N:P and C:P stoichiometric ratios and the soil structural stability index (SSI). These treatments increased soil pH by 5–6%, SOC by 74–82%, TN by 58–68%, exchangeable Ca by 76–81%, total P by 17–21%, the N:P ratio by 40%, C:P ratio by 43–51%, SSI by 71–79%, potato tuber yields by 17–21% and wheat yields by 21–32% over the control. Therefore, it is concluded that pruning and application of alnus green manure can significantly improve soil health and crop productivity on degraded soils in the study area. [ABSTRACT FROM AUTHOR]

The species diversity of the floodplain forest communities in the North-East of the Russian Federation was studied on the basis of 177 geobotanical releves conducted in the north of the Koryak Okrug, the North-East of Magadan Oblast, and the southern Chukotka. This work aims at analysing the species and community diversity of the floodplain forests depending on the habitat conditions and their position in the successional series. Geobotanical characteristics of communities in chosenia (Chosenia arbutifolia), Mongolian poplar (Populus suaveolens), willow (Salix udensis, narrow-leaf willow S. schwerinii), and alder (Alnus hirsuta) forests were displayed by dominant-determinant classification. The community diversity of the floodplain forests is represented by 19 associations, grouped into 5 series. The floristic composition and structure of the floodplain forests' communities were characterized, the Shannon and Pielou indices, species richness, species percentage coverage, and layer density were estimated. Compared to the forests of the Kamchatka Peninsula, the floodplain forests of North-East Russia were characterized by low syntaxonomic diversity and represented by floristically poor communities. The structure and dynamics of the floodplain forests' communities are discussed. The indicators of species diversity and evenness were calculated for each of the studied communities. The lowest Shannon index appeared to the pioneer chosenia communities with sparse herb cover, found on recent pebble sediments; the highest index was found for herb-moss poplar forests that occupied the highest elevations of the floodplain. The rest of the associations had intermediate values of the Shannon index. The species diversity tended to increase over the sequence of alluvial succession. The obtained data suggested that the species diversity of communities might increase during succession and depend on habitat floodplain regime and alluvial index decrease. [ABSTRACT FROM AUTHOR]

The Diels—Alder reaction of 16-(3-trimethylsilyloxybutadienyl)furanolabdanoids with 5-methylene(arylidene)-3,3-dimethyl-2,4-dioxane-1,5-diones or 5-methylene(arylidene)-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-triones in the presence of l-proline proceeded regioselectively and led to 7-furanoterpenyl-substituted 3,3-dimethyl-2,4-dioxaspiro[5.5]-undecane-1,5,9-triones or 2,4-dimethyl-2,4-diazaspiro[5.5]undecane-1,3,5,9-tetraones, respectively. The conditions for the one-pot synthesis of terpenyl-substituted dioxaspiro-[5.5]undecane-1,5,9-triones by the l-proline catalyzed three-component Knoevenagel—Diels—Alder reaction of diterpenoid enone, aldehyde, and the Meldrum's acid were proposed. A diterpenoid analog of anticancer agents with an 11-(biphenyl-4-yl)-2,4-di-oxaspiro[5.5]undecanone substituent was synthesized by the Suzuki reaction of the obtained bromophenyl-substituted spirocyclic ketone with 3,4,5-(trimethoxyphenyl)boronic acid. [ABSTRACT FROM AUTHOR]

The chemical composition, secondary metabolite concentration, digestibility parameters, and effect of polyethyleneglycol (PEG) on gas and methane production of plant material from four forage liana species: Clematis cirrhosa, Smilax aspera, Rubus ulmifolius and Hedera helix grazed by ruminants of Ain Khiar alder grove during the year were determined to assess their nutritive potential as well as their anti-methanogenic properties. C. cirrhosa and R. ulmifolius show the highest crude protein (CP) content (12.88–20.99%/kg DM), moderate NDF (32.78–45.9%/kg DM) and low ADL (5.11–12.97%/kg DM), making them the most digestible (48.06–65.04%). The incubated substrates of H. helix in autumn and winter had the lowest digestibility values (32.6 and 35.92%, respectively), given their high lignin contents (17.21 and 23.21%, respectively) and the effective nature of their tannins. The addition of PEG improved their gas production with increasing rates of 23.37% and 41.9%, respectively. This was not the case with C. cirrhosa in winter and spring for which PEG had a depressing effect on gas (− 4.42 and − 2.02%) and methane production (Algeria 37.23 and 33.3%), respectively. Based on the obtained results, the studied species confirm the excellent nutritive profiles that could guarantee a feeding resource throughout the year. [ABSTRACT FROM AUTHOR]

Let Δ d (a , -) (n) = q d (a) (n) - Q d (a , -) (n) where q d (a) (n) counts the number of partitions of n into parts with difference at least d and size at least a, and Q d (a , -) (n) counts the number of partitions into parts ≡ ± a (mod d + 3) excluding the d + 3 - a part. Motivated by generalizing a conjecture of Kang and Park, Duncan, Khunger, Swisher, and the second author conjectured that Δ d (3 , -) (n) ≥ 0 for all d ≥ 1 and n ≥ 1 and were able to prove this when d ≥ 31 is divisible by 3. They were also able to conjecture an analog for higher values of a that the modified difference function Δ d (a , - , -) (n) = q d (a) (n) - Q d (a , - , -) (n) ≥ 0 where Q d (a , - , -) (n) counts the number of partitions into parts ≡ ± a (mod d + 3) excluding the a and d + 3 - a parts and proved it for infinitely many classes of n and d. We prove that Δ d (3 , -) (n) ≥ 0 for all but finitely many d. We also provide a proof of the generalized conjecture for all but finitely many d for fixed a and strengthen the results of Duncan et al. We provide a conditional linear lower bound on d for the generalized conjecture by using a variant of Alder's conjecture. Additionally, we obtain asymptotic evidence that this modification holds for sufficiently large n. [ABSTRACT FROM AUTHOR]

The primary succession of ectomycorrhizal (ECM) fungi has been well described for Pinus and Salix, but the succession for other pioneer hosts is almost unknown. Here, we investigated ECM fungal communities of Alnus sieboldiana at different host growth stages in a primary successional volcanic site on Izu-Oshima Island, Japan. ECM root tips were collected from 120 host individuals, encompassing seedling, sapling, and mature tree stages. The taxonomic identity of the ECM fungi was determined based on rDNA internal transcribed spacer region sequences. Nine molecular taxonomic units were detected from a total of 807 root tips. The initial ECM fungal community on the pioneer seedlings was composed of only three species, where an undescribed Alpova species (Alpova sp.) was exclusively frequent. With host growth, other ECM fungal species were added to the communities, while the initial colonizers remained even at mature tree stages. Thus, the ECM fungal composition significantly changed along host growth stages and showed the nested community structure. Although most of the ECM fungi confirmed in this study had a broad Holarctic geographical distribution, the Alpova sp. had no previous records in other regions. These results suggest that a locally evolved Alpova sp. plays an essential role in the initial seedling establishment of A. sieboldiana at early successional volcanic sites. [ABSTRACT FROM AUTHOR]

Cadmium, Mn, and Zn are mobilised by plants commonly growing in floodplains, most notably willows (Salix) and alder (Alnus). These plants accumulate unwanted elements (Cd) or excessive element concentrations (Mn, Zn) in their foliage, thus introducing them into the food web and enriching them in floodplain surface by litterfall. In floodplain of the Litavka River in Czechia, contaminated by historical mining activities, up to 100 mg kg−1 Cd and up to several thousand mg kg−1 Mn and Zn are present in willow leaves in autumn, probably close maxima for sustainable plant growth. Willows and alders show seasonal growth of their foliar Mn and Zn. The willow leaves showed Cd/Zn larger than contaminated fluvisol of the Litavka River. Senesced willow leaves thus contribute to spread of risk elements from historically contaminated floodplains back to river water even without the bank erosion. Alders and willows alter geochemical cycles of Cd, Mn, and Zn in fluvial systems and increase Cd/Zn and Mn/Fe concentration ratios and Cd and Mn concentrations in fluvially transported particles relative to global geochemical averages as well as relative to floodplain sediments. Willows, in particular Salix fragilis L., S. aurita L, and S. cinerea L are particularly important "plant pumps". Other common floodplain plants, such as bird cherry (Prunus padus L.) and herbaceous plants (common nettle, Urtica dioica L. and grasses, Poaceae) do not contribute to those phenomena. [ABSTRACT FROM AUTHOR]

Background : Surgery for posterior fossa tumours (PFTs) in children is associated with bulbar palsy and swallowing difficulties although this risk is not well defined in the literature and issues contributing to dysphagia following surgery are not fully understood. Aims: This study aims to study the eating, drinking and swallowing function of children following PFT resection in a specialist paediatric neurosurgery centre. This included the frequency and duration of dysphagia, the risk of aspiration and the link between tumour type and dysphagia. Materials and methods: This is a retrospective review of children undergoing surgery for PFT between 2014 and 2019. Information was obtained from the patients' hospital and speech and language therapy (SLT) notes, oncology database and clinical letters. The International Dysphagia Diet Standardisation Initiative (IDDSI) Framework was used to describe food and fluid modifications. Results: Seventy children had surgery to resect a posterior fossa tumour at Alder Hey from 2014 to 2019. Thirty-one children were included in the study following referral to SLT. Videofluoroscopy (VF) was undertaken at our institution in 68% (21/31) of cases. Fifty-two percent (11/21) of children aspirated or were considered at risk, and 55% (6/11) of those who aspirated showed silent aspiration. After 3 months, 43% (13/30) still required modified food and/or fluid textures, with this proportion reducing as time progressed. By tumour type, VF was performed in 5/7 medulloblastoma patients with 3/5 showing aspiration and 3/3 silently aspirating; in 8/9 patients with ependymoma with 4/8 patients aspirating with 2/4 showing silent aspiration; and 6/12 glioma patients with 4/6 aspirating with 1/4 showing silent aspiration. Conclusion: Swallowing difficulties, including silent aspiration, are an important complication of PFT resection. A proportion of children will need ongoing food and/or fluid modification. Further study into dysphagia following PFT resection is indicated. [ABSTRACT FROM AUTHOR]

Leaf litter that enters to rivers and streams generates leaf packs of diverse mass, but it is not clear if increasing litter mass of these accumulations modifies their decomposition rates and invertebrate assemblages associated. We tested whether greater initial leaf litter masses (3, 5, or 7 g) modified the breakdown rates and colonization of alder litterbags by invertebrates in two Iberian mountain streams. Similar to most previous experimental studies that compared leaf litter masses of 5 g or less in streams, higher initial masses reduced the percentage of lost leaf litter, but only when compared with litterbags that had the lowest mass (3 g). We found that greater initial mass did not hinder large invertebrates accessing the leaf litter, and it did not increase the ability of litterbags to provide refuges from predators. Higher initial mass was positively related to invertebrate diversity and total invertebrate abundance (animals/litterbag), but negatively related to invertebrate density (animals/g of litter remaining), possibly due to the geometry of leaf litter packs because a greater leaf mass (i.e., greater volume) reduces the surface area:volume ratio in a non-uniform manner, as well as decreasing the fraction of the leaf litter that is exposed directly to water flow. [ABSTRACT FROM AUTHOR]

Forkhead Box M1 (FOXM1) is known to regulate cell proliferation, apoptosis and tumorigenesis. The lignan, (−)-(2R,3R)-1,4-O-diferuloylsecoisolariciresinol (DFS), from Alnus japonica has shown anti-cancer effects against colon cancer cells by suppressing FOXM1. The present study hypothesized that DFS can have anti-cancer effects against glioblastoma (GBM) tumorspheres (TSs). Immunoprecipitation and luciferase reporter assays were performed to evaluate the ability of DFS to suppress nuclear translocation of β-catenin through β-catenin/FOXM1 binding. DFS-pretreated GBM TSs were evaluated to assess the ability of DFS to inhibit GBM TSs and their transcriptional profiles. The in vivo efficacy was examined in orthotopic xenograft models of GBM. Expression of FOXM1 was higher in GBM than in normal tissues. DFS-induced FOXM1 protein degradation blocked β-catenin translocation into the nucleus and consequently suppressed downstream target genes of FOXM1 pathways. DFS inhibited cell viability and ATP levels, while increasing apoptosis, and it reduced tumorsphere formation and the invasiveness of GBM TSs. And DFS reduced the activities of transcription factors related to tumorigenesis, stemness, and invasiveness. DFS significantly inhibited tumor growth and prolonged the survival rate of mice in orthotopic xenograft models of GBM. It suggests that DFS inhibits the proliferation of GBM TSs by suppressing FOXM1. DFS may be a potential therapeutic agent to treat GBM. [ABSTRACT FROM AUTHOR]

The diploid A. glutinosa (L.) Gaertn. is widespread throughout the European continent, except in the Iberian and Balkan Peninsulas where tetraploid populations have been discovered. We focused on the tetraploid species described as A. rohlenae Vít, Douda and Mandák that occupies the western part of the Balkan Peninsula, where it has likely completely replaced the diploid species. While the distribution range of the diploid A. glutinosa s. str. is well known, the exact distribution range of the tetraploid A. rohlenae is unknown. Here, we report the first exact distribution of the tetraploid A. rohlenae and the anticipated hybrid zones in which it is in contact with diploid populations using flow cytometry and morphometrics. Tetraploids are located primarily in the mountainous parts of the study area and towards the lowlands are gradually being replaced by diploids, forming a contact zone. We compare the main morphological characteristics of both species. Due to the geographical proximity of the study species, the morphological differences between them are clear outside the contact zones. However, within the contact zones, we recorded hybridisations that obscure the morphological differences between species, probably due to the presence of triploid hybrids. [ABSTRACT FROM AUTHOR]

Alder (Alnus spp.) and Pacific salmon (Oncorhynchus spp.) provide key nutrient subsidies to freshwater systems. In southwestern Alaska, alder-derived nutrients (ADNs) are increasing as alder cover expands in response to climate warming, while climate change and habitat degradation are reducing marine-derived nutrients (MDNs) in salmon-spawning habitats. To assess the relative influences of ADN and MDN on aquatic microbial community structure and function, we analyzed lake chemistry, bacterial community structure, and microbial metabolism in 13 lakes with varying alder cover and salmon abundance in southwestern Alaska. We conducted bioassays to determine microbial nutrient limitation and physical factors modulating microbial response to nutrient inputs (+N, +P and +NP treatments). Seasonal shifts in bacterial community structure (F = 7.47, P < 0.01) coincided with changes in lake nitrogen (N) and phosphorus (P) concentrations (r2 = 0.19 and 0.16, both P < 0.05), and putrescine degradation (r2 = 0.13, P = 0.06), suggesting the influx and microbial use of MDN. Higher microbial metabolism occurred in summer than spring, coinciding with salmon runs. Increased microbial metabolism occurred in lakes where more salmon spawned. Microbial metabolic activity was unrelated to alder cover, likely because ADN provides less resource diversity than MDN. When nutrients were added to spring samples, there was greater substrate use by microbial communities from lakes with elevated Chl a concentrations and large relative catchment areas (β estimates for all treatments > 0.56, all P < 0.07). Thus, physical watershed and lake features mediate the effects of nutrient subsidies on aquatic microbial metabolic activity. [ABSTRACT FROM AUTHOR]

The adverse effects of combustion waste disposal sites could be limited by their biological stabilization. This work presents a review of the literature on the utility of species of alder (black, grey and green) in the biological stabilization, and potentially phytoremediation, of combustion waste disposal sites. All three alder species studied are characterized by high survival rates and good growth parameters, with black alder displaying better growth parameters compared to grey alder. In general, the three alder species have been found to have similar and positive effects on the physicochemical properties of combustion waste, with the observed differences being relatively small. In combustion waste disposal site located in Central Poland, litter pH was slightly acidic (pH in KCl 6.3) to neutral (pH in KCl 6.7), which is favourable for strongly alkaline combustion wastes. Accumulation of litter layer ranged from 2.9 to 3.6 Mg ha–1, and grey alder litter was characterized by the highest content of nutrients (N-P-K). Organic C content in the 0–5 cm mineral layer (A) increased to 38.06 and 47.80 g kg–1, respectively for green and black alder. However, the selection of a single tree species for the reclamation of combustion waste needs to be based not only its phytoameliorative function but also its growth and biomass parameters. Given those parameters, black alder is strongly recommended. This species has a similar effect on the properties of combustion waste as grey alder, but it exhibits better growth parameters. Green alder, being a shrub with lower biomass and litter fall than the other two species, exerts weaker ameliorative and soil development effects, but may be used on slopes to counteract erosion processes. [ABSTRACT FROM AUTHOR]

Leaf litter decomposition in streams is a fundamental ecosystem process that allows for the cycling of nutrients. The rate at which leaf litter decomposes is greatly controlled by its intrinsic characteristics. However, intraspecific variation in leaf litter characteristics poses a major challenge for large-scale studies aiming at identifying the environmental moderators of leaf litter decomposition. Thus, several standardized organic substrates have been proposed as surrogates for leaf litter. Tea bags were proposed as a standardized alternative to leaf litter for studies in soil and their use in aquatic ecosystems has been growing in recent years. It is therefore necessary to evaluate how tea is colonized and decomposed by aquatic microbial decomposers to assess its usefulness as a surrogate for leaf litter in litter decomposition studies. Here we compared the microbial colonization (based on the reproductive activity of aquatic hyphomycetes) and decomposition of green and rooibos teas and native alder leaf litter in two streams differing in environmental conditions. Colonization of green tea was lower than that of alder leaf litter, but their decomposition rates were similar. In contrast, colonization of rooibos tea was similar to that of alder leaf litter, but it decomposed 3–4 × slower. Results were consistent in both streams. Despite differences in magnitude, dynamics of microbial colonization and decomposition of tea were similar to those of alder leaf litter and were sensitive to substrate characteristics. Tea may be used as a surrogate for leaf litter in studies addressing microbial-driven leaf litter decomposition in streams. [ABSTRACT FROM AUTHOR]

Background: Black alder (Alnus glutinosa) forests are in severe decline across their area of distribution due to a disease caused by the soil-borne pathogenic Phytophthora alni species complex (class Oomycetes), "alder Phytopththora". Mapping of the different types of damages caused by the disease is challenging in high density ecosystems in which spectral variability is high due to canopy heterogeneity. Data obtained by unmanned aerial vehicles (UAVs) may be particularly useful for such tasks due to the high resolution, flexibility of acquisition and cost efficiency of this type of data. In this study, A. glutinosa decline was assessed by considering four categories of tree health status in the field: asymptomatic, dead and defoliation above and below a 50% threshold. A combination of multispectral Parrot Sequoia and UAV unmanned aerial vehicles -red green blue (RGB) data were analysed using classical random forest (RF) and a simple and robust three-step logistic modelling approaches to identify the most important forest health indicators while adhering to the principle of parsimony. A total of 34 remote sensing variables were considered, including a set of vegetation indices, texture features from the normalized difference vegetation index (NDVI) and a digital surface model (DSM), topographic and digital aerial photogrammetry-derived structural data from the DSM at crown level. Results: The four categories identified by the RF yielded an overall accuracy of 67%, while aggregation of the legend to three classes (asymptomatic, defoliated, dead) and to two classes (alive, dead) improved the overall accuracy to 72% and 91% respectively. On the other hand, the confusion matrix, computed from the three logistic models by using the leave-out cross-validation method yielded overall accuracies of 75%, 80% and 94% for four-, three- and two-level classifications, respectively. Discussion: The study findings provide forest managers with an alternative robust classification method for the rapid, effective assessment of areas affected and non-affected by the disease, thus enabling them to identify hotspots for conservation and plan control and restoration measures aimed at preserving black alder forests. [ABSTRACT FROM AUTHOR]

Leaf litter of alder (Alnus glutinosa) is a key resource to detrital stream food webs. Due to its high quality and palatability, it is readily colonised by microorganisms and consumed by detritivores, contributing significantly to carbon and nutrient cycling and to ecosystem functioning. Given that this species has declined due to the spread of the pathogen Phytophthora alni, we investigated how its loss would alter leaf litter decomposition and associated stream assemblages of aquatic hyphomycetes and invertebrates, in a field experiment conducted in three streams. We compared litter mixtures containing alder plus three other species (Corylus avellana, Quercus robur and Salix atrocinerea; that is, 4-species treatments) with mixtures that excluded alder (3-species treatments) and all the monocultures (1-species treatments). The loss of alder reduced decomposition rates, despite the existence of an overall negative diversity effect after 3 weeks of exposure (that is, monocultures decomposed faster than mixtures) and no diversity effect after 6 weeks. Aquatic hyphomycete and detritivore assemblage structure in the mixture without alder differed from those of the mixture with alder and the monocultures, and the former had lower fungal sporulation rate and taxon richness. Our results suggest that alder loss from the riparian vegetation can significantly slow down the processing of organic matter in streams and produce shifts in stream assemblages, with potential consequences on overall ecosystem functioning. We highlight the importance of assessing the ecological consequences of losing single species, particularly those especially vulnerable to stressors, to complement the multiple studies that have assessed the effects of random species loss. [ABSTRACT FROM AUTHOR]

It has been established that resurvey of historical vegetation stands, even those not marked permanently, could foster our understanding of vegetation dynamics and changes in structure and composition over time. However, such studies are poorly available, particularly in remote landscapes of the Indian Himalaya. There exists a complete lack of resurveys, which has limited our ability to provide reliable evidence of changes over the decades. This study, for the first time in the Indian Himalaya, considered repeat surveys (nearly after 25 years) of vegetation stands in eleven forest communities of the buffer zone of NDBR (Nanda Devi Biosphere Reserve). Thirty historical forest stands, earlier studied in 1988–1990, were revisited during 2012–2014 and investigated using the same survey methods as used in the previous study. We found that previously reported dominant tree species, i.e., Alnus nepalensis, Acer cappadocicum, Quercus floribunda, Quercus semecarpifolia, Hippophae salicifolia, and Betula utilis, in nine out of eleven communities in the study area are continuing to exhibit dominance in the community. However, a significant increase in species richness and density in the seedling and sapling layer in Quercus floribunda, Quercus semecarpifolia, Rhododendron arboreum, and Abies pindrow is indicative of the ongoing process of change in forest composition. The compositional features of plant communities, when analyzed through Community Change Sensitivity (CCS) approach, identified Quercus floribunda, mixed Quercus—deciduous spp., Hippophae salicifolia, and Abies pindrow as the most change-sensitive communities in the study area and thus can be prioritized as the long-term ecological monitoring sites in the west Himalaya to understand intensity and patterns of changes. The potential changes based on the ecological information from two time period compositional data sets, having conservation and management implications, should be accommodated in the long-term perspective plans of the reserve. [ABSTRACT FROM AUTHOR]

Alnus acuminata Kunth. (alnus) is widely used in agroforestry systems across the globe and is believed to provide multiple ecosystem services; however, evidence is lacking in agroforestry literature to support the perceived benefits, particularly in Rwanda. To understand carbon sequestration potential and other benefits of alnus, a household survey, tree inventory and destructive sampling were conducted in north-western Rwanda. Over 75% of the respondents had alnus trees in their farms. The trees provide stakes for climbing beans, firewood and timber. They also improve soil fertility and control soil erosion. Farmers had between 130 and 161 alnus trees per hectare with an average height of 7.7 ± 0.59 m and diameter at breast height of 16.3 ± 1.39 cm. The largest biomass proportion was found in stems (70.5%) while branches and leaves stock about 16.5 and 13% of the total biomass, respectively. At farm level, aboveground biomass of alnus trees was estimated to be 27.2 ± 0.7 Mg ha−1 representing 13.6 Mg of carbon (C) per hectare. Biomass carbon increased with tree size, from 7.1 ± 0.2 Mg C ha−1 in 3 years old trees to 34.4 ± 2.2 Mg C ha−1 in 10 years old trees. The converse was observed with elevation; biomass carbon decreased with increasing elevation from 21.4 ± 1.29 Mg C ha−1 at low (2011–2110 m) to 9.6 ± 0.75 Mg C ha−1 in the high elevation (> 2510 m). In conclusion, alnus agroforestry significantly contributes to carbon sequestration, although the magnitude of these benefits varies with tree age and elevation. Planting alnus trees on farms can meet local needs for stakes for climbing beans, wood and soil fertility improvement, as well as the global need for regulation of climate change. [ABSTRACT FROM AUTHOR]

Despite their great utility in synthetic and materials chemistry, Diels-Alder (DA) and retro Diels-Alder (rDA) reactions have been vastly unexplored in promoting self-assembly processes. Herein we describe the first example of a retro Diels-Alder (rDA) reaction-triggered self-assembly method. Release of the steric bulkiness associated with the bridged bicyclic DA adduct by the rDA reaction allowed generation of two building blocks that spontaneously self-assembled to form a supramolecular polymer. By employing photopolymerizable lipid building blocks, we demonstrated the efficiency of the rDA-based self-assembly strategy. Generation of reactive functional groups (maleimide and furan) that can be used for further modification of the supramolecular polymer is an additional meritorious feature of the rDA-based approach. Advantage was taken of reactive functional groups to fabricate stimulus-responsive selective and tunable colorimetric sensors. The strategy developed in this study should be useful for the design of systems that participate in triggered molecular assembly. Despite their great utility in synthetic and materials chemistry, Diels-Alder and retro Diels-Alder reactions have been vastly unexplored in promoting self-assembly processes. Here the authors show the release of steric bulkiness associated with a bridged bicyclic Diels Alder adduct by the retro Diels-Alder reaction that allowed generation of two building blocks that spontaneously self-assembled to form a supramolecular polymer. [ABSTRACT FROM AUTHOR]

Past work shows a significant negative correlation between foliar oregonin concentration and western tent caterpillar (Malacosoma californicum Packard) feeding on red alder (Alnus rubra Bong.). Above an oregonin threshold of 20% leaf dry weight, little feeding by caterpillars is observed. Concentrations of defensive chemicals are influenced by plant genotype, environmental conditions, insect feeding, and the interactions of these factors. Our objective was to measure the effects of nitrogen (N) availability and wounding on foliar oregonin and condensed tannin concentrations in red alder genotypes. One-year-old seedlings from 100 half-sib red alder families were treated with two levels of ammonium nitrate (NH4NO3) for two growing seasons in a common garden. In the second year, leaves from 50 families from the fertilization experiment were used in a bioassay feeding experiment to determine the effects of N fertilization and genotype on WTC damage, and to identify a subset of 20 families with a range of damage to analyze for phytochemical composition. In separate experiments, wound-induction treatments were conducted outdoors and, in a greenhouse using the N treated trees in their third and fourth year, respectively. Foliar condensed tannin, oregonin and N concentrations were measured and ranked among the plant genotypes, and between the two N treatments and two wounding treatments. Results showed that oregonin and condensed tannin concentrations varied among the alder genotypes. Leaf N concentration was negatively correlated with concentration of oregonin. Neither of the measured phenolic compounds responded to wounding. The results suggest that red alder foliar oregonin and condensed tannin are likely constitutive defenses that are largely determined by genotype, and that the negative correlation of defense compounds with plant internal N status holds in this N-fixing tree. [ABSTRACT FROM AUTHOR]

In many watersheds, nitrogen (N)-fixing alder (Alnus spp.) provides key nutrient subsidies to terrestrial and aquatic ecosystems. The importance of these subsidies may increase as alder cover expands under climate warming at high latitudes. We assessed how landscape features and meteorological conditions affect aquatic N and phosphorus (P) availability and stoichiometry in 26 streams across natural gradients of alder cover in southwestern Alaska over the spring and summer, covering 4 years. Analyses of resin lysimeter samples from select watersheds showed that annually, soils under alder leached almost three times more N, and two times more P than under non-alder vegetation. Stream NO3− concentrations displayed a non-linear relationship with alder cover; NO3− was low where alder cover was < 30%, but increased markedly where alder cover was > 30%. Watershed elevation was inversely related to alder cover, stream NO3− concentrations, and stream NO3− yields. Dissolved and particulate stream P were unrelated to alder cover, watershed elevation or discharge, highlighting decoupling of controls on P between terrestrial and aquatic ecosystems. Snowmelt-associated nutrient pulses and hydrology likely resulted in greater stream N and P in the spring, compared to the summer. However, weather parameters only impacted stream N via their interaction with alder. Stream DIN:TP increased with alder cover and decreased with elevation, suggesting that alder intensified P-limitation. Hence, aquatic P-limitation may become increasingly pronounced as climate-induced alder expansion continues. These results demonstrate that the elevational gradient in watershed alder cover determined spatial patterns in stream N availability and nutrient limitation. [ABSTRACT FROM AUTHOR]

The green alder Alnus alnobetula s. l., a widely distributed subarctic-alpine shrub species, has been studied using three chloroplast DNA regions: trnH-psbA, trnS-trnG, and psaA-trnS. In addition, new chloroplast primers coding the trnT-GGT cpDNA regions and five cpDNA microsatellite loci (cpSSR) have been developed for this species. The population subdivision is very high (Nst = 0.869, Gst = 0.807, Fst = 0.883), suggesting a distinct phylogeographic structure (Nst > Gst, p < 0.0001) and a sharp contrast between the haplotype-rich eastern part of the species range and the almost completely uniform western part (Siberia, Ural). According to a phylogenetic analysis, the common haplotype of A. alnobetula subsp. fruticosa in the western part of the range originated from northeastern refugia (West Beringia) as a result of interglacial recolonization, including bottleneck events. Three highly divergent cpDNA lineages of green alder that have been resolved in the Russian Far East are largely concordant with A. alnobetula subsp. kamtschaticа, A. alnobetula subsp. mandschurica, and A. alnobetula subsp. maximowiczii. The populations of Sakhalin Island are divided into three phylogeographic groups (southern, central, and northern) corresponding to the different floristic zones and different subspecies. The green alder populations from central Sakhalin have a haplotype-rich composition including different genetic lineages that confirm the existence of a hotspot of genetic diversity in this part of the island. [ABSTRACT FROM AUTHOR]

Particleboards based on a mixture of grey alder (Alnus incana (L.) Moench) wood particles (sieve fraction 0.4-2 mm) and 15 or 25% of lignin powder obtained by hot pressing from four different industrial sources were investigated. Their density, thickness swelling, water absorption, modulus of rupture, modulus of elasticity in bending, and internal bond strength were determined. It was founded that the source and amount of the added lignin noticeably affected all tested properties of the particleboards. [ABSTRACT FROM AUTHOR]

Plants synthesize a wide range of bioactive secondary metabolites to defend against pests and pathogens. Red alder (Alnus rubra) bark, root, and leaf extract have a long history of use in traditional medicine and hygiene. Diarylheptanoids, especially oregonin ((5S)-1,7-bis(3,4-dihydroxyphenyl)-5-(β-D-xylopyranosyloxy)-heptan-3-one), have been identified as major bioactive constituents. Diarylheptanoids have become a focus of research following reports of their antioxidant, antifungal, and anti-cancer activities. Recent data suggest that high oregonin concentration is associated with resistance of red alder leaves to western tent caterpillar (Malacosoma californicum) defoliation. Here we test effects of this compound directly on leaf-eating insects. Purified oregonin was examined in insect choice and toxicity tests using lepidopteran caterpillars. The compound exhibited significant anti-feedant activity against cabbage looper (Trichoplusia ni), white-marked tussock moth (Orgyia leucostigma), fall webworm (Hyphantria cunea), and M. californicum at concentrations corresponding to oregonin content of the most resistant alder clones in previous experiments. Toxicity tests were carried out with cabbage looper larvae only, but no contact or ingested toxicity was detected. Our results suggest that oregonin at levels found in red alder leaves early in the growing season may contribute to protecting red alder from leaf-eating insects. [ABSTRACT FROM AUTHOR]

Let Δ d (a , b) (n) = q d (a) (n) - Q d (b) (n) where q d (a) (n) counts the number of partitions of n into parts with difference at least d and size at least a, and Q d (b) (n) counts the number of partitions into parts ≡ ± b mod d + 3 . In 1956, Alder conjectured that Δ d (1 , 1) (n) ≥ 0 for all positive n and d. This conjecture was proved partially by Andrews in 1971, by Yee in 2008, and was fully resolved by Alfes, Jameson and Lemke Oliver in 2011. Alder's conjecture generalizes several well-known partition identities, including Euler's theorem that the number of partitions of n into odd parts equals the number of those into distinct parts, as well as the first of the famous Rogers–Ramanujan identities. In 2020, Kang and Park constructed an extension of Alder's conjecture which relates to the second Rogers–Ramanujan identity by considering the difference Δ d (a , b , -) (n) = q d (a) (n) - Q d (b , -) (n) , where Q d (b , -) (n) counts the number of partitions into parts ≡ ± b mod d + 3 excluding the part d + 3 - b . Kang and Park conjectured that Δ d (2 , 2 , -) (n) ≥ 0 for all d ≥ 1 and n ≥ 0 , and proved this when d = 2 r - 2 and n is even. Here, we prove Kang and Park's conjecture for all d ≥ 62 . Toward proving the remaining cases, we adapt work of Alfes, Jameson and Lemke Oliver to generate asymptotics for the related functions. Additionally, we present a more generalized conjecture for higher a = b and prove it for infinite classes of n and d. [ABSTRACT FROM AUTHOR]

Seabirds that form large colonies often act as biovectors that transport and concentrate large amounts of nutrients, metals, and contaminants from marine feeding areas to inland breeding grounds. This enrichment can potentially transform and structure primary productivity, vegetation communities, and species richness. In a previous paleolimnological study, we examined approximately 1700 years of population change in the world's largest colony of Leach's Storm-petrel (Hydrobates leucorhous) on Baccalieu Island (Newfoundland and Labrador, Canada) and, using a variety of proxies, we identified two peaks in colony around 500 and 1980 CE. Here, we analyzed the same sediment cores for fossil pollen assemblages to explore the effects of changing seabird populations on terrestrial vegetation. Aerial imagery revealed the island's vegetation cover that increased from about 23% to about 58% between 1940 and 2017, in part coinciding with the rapid colony growth until around 1980. Palynological analyses indicated shifts from tree and shrub habitat to storm-petrels' preferred habitat of fern, grass, and moss during peak seabird abundances around 500 and 1980 CE. Also, during peaks in colony size, nitrogen-fixing alder (Alnus spp.) decreased in relative abundance likely due to poorer competitive potential because of guano-derived nitrogen fertilization. Furthermore, we observed increases in fungal hyphae concurrent with the inferred size of the storm-petrel colony, providing the potential for a novel proxy to track burrowing seabirds in sediment records. Collectively, our data show that storm-petrels acted as ecosystem engineers by markedly modifying the island's vegetation cover and composition. If global seabird colonies continue to decline at current rates, there may be considerable bottom-up ramifications to terrestrial island ecosystems. [ABSTRACT FROM AUTHOR]

The relationship between biodiversity and litter decomposition has received considerable attention, but the complex biodiversity effects on decomposition and the underlying mechanisms are still unclear, especially in boreal riparian forest ponds. Here, we collected leaf litter from an N2-fixing species (Alnus sibirica) and two non-N2-fixing species (Betula platyphylla and Betula fruticosa) in a boreal riparian forest, northeast China. Then, we mixed leaf litter with varying composition and evenness to create a large gradient of litter functional identity and functional diversity, and used the litterbag method to examine the effect of altering plant composition on litter mass loss and nitrogen (N) release during 2 years of decomposition in forest ponds. Over 2 years of decomposition, the presence of A. sibirica in litter assemblages accelerated mass loss and N release by improving functional identity and increasing functional diversity of litter mixtures. Irrespective of the dominant species, litter mass loss generally increased with rising evenness, whereas the effect of species evenness on N release was dependent on the dominant species. When all litter mixtures were pooled, litter mixing effects on mass loss and N release correlated positively with litter functional diversity. Moreover, the decomposition dynamics of litter mixtures were regulated by litter functional diversity and the resulting mixing effects, as well as the community-weighted mean traits such as N and lignin concentrations. These findings confirm the importance of litter functional identity and functional diversity in driving decomposition processes of litter mixtures, and also indicate that increased abundance of N2-fixing species will accelerate litter decomposition and enhance N release in boreal riparian forest ponds. [ABSTRACT FROM AUTHOR]

Annual pollen accumulation rates of the main tree and shrub taxa of European Russia (Picea, Pinus, Betula, Alnus, Quercus, Tilia, Fraxinus, Ulmus and Corylus), as well as several herbaceous taxa (Poaceae, Cyperaceae, Chenopodiaceae and Artemisia), were obtained using Tauber pollen traps which were placed along a northwest to southeast transect in European Russia. The work was carried out within the framework of the Pollen Monitoring Programme (PMP). The data were analysed using both traditional interpretations of PAR (pollen accumulation rate) values and numerical methods (linear regressions and canonical correspondence analysis, CCA). The various vegetation zones: broadleaved-coniferous forest, broadleaved forest and forest-steppe, differ from each other by the absolute pollen values (PARs) of forest-forming taxa and several wind-pollinated herbs. However, no statistical support for zonal differentiation based on these PARs has been found. The only obvious difference was observed between the forest zone and the forest-steppe. The climatic gradient along the NW–SE transect is reflected by changes in pollen values, but is smoothed due to human influence during past centuries and as a consequence of the dominance of secondary vegetation formations. The highest total PAR, as well as PARs of all the forest-forming taxa, was observed in the southern part of the mixed broadleaved-coniferous forest zone (RU-ZV). The PARs of thermophilic taxa (Tilia, Fraxinus, Acer, Ulmus, Quercus and Corylus), as well as of Picea correspond to warmth availability which is under the influence of a combination of latitude, continentality of climate and microclimatic conditions. According to linear regressions, Picea, Tilia, Quercus and Corylus PARs correspond to Tjul, the July temperature of the previous season. Canonical correspondence analysis indicates that temperature, in particular Tjul, is the main climatic parameter controlling the variation of modern pollen rain. [ABSTRACT FROM AUTHOR]

Alnus pollen has been frequently detected in the atmosphere of different airborne sampling sites of Southern Spain. However, Alnus sp. populations are very scarce and fragmented in the area, being restricted to a few river valleys in the southwest, and other further away regions of the Iberian Peninsula. This leads to think that the airborne pollen detected could be mainly the result of a medium- or long-distant transport. So, the aim of this study was to characterize the annual patterns of airborne Alnus pollen detected at three different locations of Malaga province, as well as to determine its possible origin, the pollen dispersion potential of these Alnus isolated populations, and their possible reproductive connectivity. Pollen sampling was conducted by means of three Hirst-type volumetric pollen traps. Samples were mounted and counted following the recommendations of the Spanish Aerobiology Network and the European Aeroallergen Society. The possible pollen sources were detected by means of a combination of meteorological information and backward air trajectories analysis. A high inter-annual variability in the annual pollen integrals was found in all the stations, favouring certain meteorological conditions a long-range transport and, therefore, causing the high concentrations detected in some specific days. Alnus pollen seems to have a heterogeneous origin with prevalence of the long-distant transport, which would suggest a possible reproductive connection among distant populations. [ABSTRACT FROM AUTHOR]

Objective: The management of paediatric hydrocephalous remains challenging with the complication and revision rates being consistent in the literature. We hypothesise that the use of a fixed pressure gravitational valve for all de novo shunt insertions decreases the rate of functional revisions and that by implementing the routine use of gravitational valves in children, we would see a reduction in over-drainage and slit ventricle syndrome. Methods: Retrospective data collection in a single centre, between February 2010 and August 2018. All patients undergoing fixed pressure gravitational Miethke valve insertion were included. We collected data on patients' demographics, reason for shunt insertion, type of valve and time to and reason for first revision. Data analysis was done with SPSS. Results: A total of 235 patients were included in our study (124 males, 111 females), aged from 0 to 18.6 years (median 0.28). A total of 99 shunt revisions were documented, 30 of which secondary to ventricular catheter malfunction and 28 secondary to infection. The overall mechanical valve survival rates were 88.5%, 86.4% and 85.5% at 1, 2 and 5 years, respectively. Shunt revision due to over-drainage was documented in only 3 cases (1.3%). Conclusion: Our results are in agreement with existing literature regarding shunt failures secondary to all extrinsic factors to the valve (infection and mechanical failure). We have shown that the use of a Miethke fixed pressure valve for all de novo shunt insertions in paediatric hydrocephalus decreases the need for functional revisions with valve survival rates being superior to the ones described for other types. [ABSTRACT FROM AUTHOR]

Wild pear (Pyrus pyraster (L.) Burgsd.) (P) and wild service tree (Sorbus torminalis (L.) Crantz) (S) are sporadic European tree species that are valued for their high-quality timber production. Although mixed plantations including companion species enhance timber quality of several trees, the performance of the association of P and S is not well known. The objective of this study was to assess growth and survival of P and S in pure plantations and in plantations mixed with other companion tree or shrub species in a non-native habitat. To answer the question of whether growth of these species is enhanced by mixtures, specific combinations of the main and companion species were established in central Chile and monitored for a 12-year period after planting. Besides each main species monoculture, five mixtures were tested: Mix1: P+S; Mix2: P+S+ the N-fixing tree Italian alder (Alnus cordata (Loisel.) Duby); and three associations of P and S including shrubs (Mix3: P+S+ Corylus avellana L., Mix4: P+S+ Sambucus ebulus L., and Mix5: P+S+ Sambucus nigra L.). Both P and S presented the highest height growth in Mix2, being 48.6% and 53.4% higher than in the monoculture, respectively. DBH growth was also enhanced in Mix2 for S. Wild service tree, which showed lower growth and survival than P, was more benefited from the mixture including Italian alder than P. Height growth, vigor and survival of the main species were highest in Mix2, even higher than in pure plantations and in Mix1 without companion species. Specific tree associations might increase the probability to obtain high-quality timber of noble species if a timely and adequate management of companion species is provided. [ABSTRACT FROM AUTHOR]

Macroscopic fungi on Caucasian alder wood (Alnus subcordata) were identified and tested as a source of betulin and betulinic acid (the most important metabolites of the Betulaceae family) to evaluate levels of phenols, flavonoids and antioxidant activity. Ganoderma applanatum, Lenzites betulina, Trichaptum biforme, Rigidoporus ulamrius, Fomes fomentarius, Schizophyllum commune, Auricularia mesenterica, and Trametes versicolor were among those identified, and they differed significantly in the level of betulin and betulinic acid and phenols, flavonoids and antioxidant properties in fungal tissues extracted with methanol and with ethanol (p ≤ 0.01). G. applanatum had the most betulin (3.642%) and S. commune the most betulinic acid (1.413%). All tested fungi had high antioxidant activity, and L. betulina had the highest (97.775%). The highest amounts of phenol (719.993 mg mL−1) and flavonoids (361.403 mg mL−1) were found in the ethanolic extract from G. applanatum. Considering the results of this study and the low cost and convenient access to these fungi, they should be good sources for producing different drugs. [ABSTRACT FROM AUTHOR]

The existence of a fire event at the Iron Age hillfort of Nabás, which is located on the southern bank of the Ría de Vigo (Galicia, NW of the Iberian Peninsula), favoured an extraordinary preservation of carbonised plant remains and offered an unusual opportunity to focus our research on the study of the final episode of a house life-cycle. The archaeobotanical approach focused on perishable materials combining charcoal, with carpology and pollen analysis, in tandem with a taphonomic assessment. The charcoal assemblage includes charcoal without signs of working, and wooden manufactures although the former group was probably related to the roof and timber of the round-house. This interpretation is based on the size and concentration of charcoal fragments, as well as the short taxonomic list (deciduous and evergreen Quercus sp., Fabaceae, Corylus avellana, Rosaceae/Maloideae, Salix/Populus, Alnus sp., Frangula alnus, Betula sp., Phragmites/Arundo and Ulmus sp.), and the recurrence of biological alterations such as xylophages' galleries and hyphae. Aggregated grains and chaff of foxtail millet (Setaria italica) were found in several samples suggesting their storage, probably inside an organic container. Finally, pollen analysis offered clues about the uses of plants such as Ericaceae during the occupation phase of the round-house. [ABSTRACT FROM AUTHOR]

The Czech Republic (CR) has an exceptionally high number of pollen sites, but large areas, such as the area south and southwest of Praha (Prague), still lack pollen records. Although we know the basic scenario of Holocene vegetation development in the CR, questions remain. Recent discussions have concerned the role of Picea abies and Abies alba in the mid and late Holocene, especially in upland regions of the CR. Quantitative vegetation reconstruction methods have shown unexpectedly high proportions of both taxa in most regions within the CR in these periods, with the exception of the lowlands. In this study we publish original data from southern Bohemia. We aim to use it to build a picture of both local vegetation and settlement development in an upland landscape where pollen records with a detailed chronology were previously lacking. The area under study, where the first intensive occupation occurred during the early Iron Age (800/750–500 bc), is characterised by poor acid soils, a subcontinental climate and gold-bearing watercourses. Iron Age settlements could have been connected with extensive gold extraction along those watercourses, and this is supported by pollen data. From the same period, a number of Viereckschanzen (rectangular ditched enclosures) have been found in the region. According to pollen data, the woods were originally dominated by Pinus and later by Abies and Picea. Abieti-Quercetum was the main woodland association, while Picea probably grew mostly on the floodplains. During the Iron Age (800/750–50 bc), a sharp and parallel decrease in both Picea and Alnus is detected. However, the extent of farmed land was limited during this period and it became established only in the early medieval period from around ad 900. A. alba and the remaining P. abies nearly disappeared by around ad 1200. [ABSTRACT FROM AUTHOR]

Background: Natural afforestation of former agricultural lands with alder species is common in Europe. Symbiotic nitrogen fixation by actinomycetes associated with alder species has been widely used for improvement of soil properties of abandoned agricultural lands, but relatively little is known of the interactions of these processes with soil type and chemical composition. We conducted a space-for time study with soil sampling under and outside grey alder tree canopies on two different soil groups to explore effects of colonisation of former agricultural lands by alder on soil properties. Results: The results were analysed using analysis of variance. During the first 25 years after afforestation of former agricultural lands there was a significant increase in content of Ctot, Ntot, K+, Fe3+, Mn2+ and available P in the topsoil (0–10 cm and 11–20 cm) of Dystric Arenosols soils, which are deficient in organic matter. Such trends were not evident in organic matter rich Endostagnic Umbrisols soils, in which exchangeable K+ concentration decreased and exchangeable Fe3+ and Al3+ concentration increased. Conclusions: The results show that the effects of grey alder on soil chemical properties depend on initial soil properties. The invasion of agricultural land by grey alder leads to spatial variability of soil chemical properties creating a mosaic pattern. [ABSTRACT FROM AUTHOR]

Shrub expansion has occurred across much of the arctic tundra over the past century. Increasing dominance of woody vegetation is expected to have global influences on climate patterns and lead to local changes in hydrological function and nutrient cycling. Changing abiotic conditions associated with shrubs will likely alter the relative fitness of neighbouring plants resulting in distinct community composition. Here, we use an extensive set of paired abiotic and biotic data to investigate the capacity for Alnus alnobetula (green alder) patches to modify the habitat of the local plant community at the taiga–tundra ecotone of the Northwest Territories, Canada. Plots were established across topographic positions in ten alder patches and adjacent, alder-free tundra. Habitat corresponded to the strongest gradient of among-site variation in abiotic measures and plant community composition, indicating that alder patch growing conditions were distinct from those of alder-free tundra. Slope position was generally unimportant in determining environmental conditions. Alder patches changed the vertical structure of the understory by increasing the maximum height of birch. Tall shrubs also decreased the richness of tundra specialists, suggesting that these species face competitive pressures from shrub expansion at the southern edge of their ranges. Our findings demonstrate that tall shrub patches can substantially modify their local environment in taiga–tundra ecotone systems, altering available habitat and acting as niche constructors for the local plant community. These habitats will therefore be important to consider in regional predictions of hydrology, nutrient cycling, and biodiversity as shrubs continue to expand across the arctic. [ABSTRACT FROM AUTHOR]

Absolute and relative content and composition of fatty acids, total lipids, and phospholipids, as principal constituents of cell membranes, were examined on vegetative buds of deciduous trees and shrubs throughout the summer and autumn–winter seasons under climatic conditions of the cryolithozone of Yakutia. Lipid metabolism was found to play an essential role in plants' adaptation to low autumnal and winter temperatures in the permafrost zone of Yakutia. The content of phosphatidylcholine in leaf buds of the birch Betula pendula Roth and the shrub Alnus alnobetula subsp. fruticosa (Rupr.) Raus increased throughout the observation period from 9.9 to 23.4 mg/g dry wt. In the autumn–winter period, the composition of fatty acids in the bud lipids of both species was characterized by a high content of unsaturated C18:2 and C18:3 acids. Biosynthesis of fatty acids in buds of deciduous trees and shrubs at a low temperature was apparently controlled by ω3-desaturase, whose activity elevated the content of α-linolenic acid from 2.9 to 5.7 mg/g in B. pendula and from 1.6 to 4.8 mg/g dry wt in A. alnobetula subsp. fruticosa. The seasonal decrease in air temperature was accompanied by an increase in the unsaturation coefficient (k) from 0.9 to 2.3 in B. pendula and from 1.4 to 1.8 in A. alnobetula subsp. fruticosa. It is proposed that the high content of polyunsaturated fatty acids in the autumn–winter period in vegetative buds of the examined woody plants is determined by a complex of climatic factors of the permafrost zone, such as a sharply contrasting day and night temperatures during plant dormancy, extremely low air temperature in winter (down to –60°С), and a short daylight period at this time of the year. [ABSTRACT FROM AUTHOR]

Application of mulch on compacted soil is a common engineering measure to suppress runoff and soil loss during ground-based mechanized forest operations. Despite the expanded use, efficacy of these rehabilitation treatments on soil quality as well as seedling survival and growth rate are crucial issues that require further attention. This study aimed to assess the efficacy of two soil amendment techniques including straw (1.27 kg m−2) and litter (1.67 kg m−2) mulch on soil properties and growth properties of Caucasian alder. Three treatments: straw mulch (SM), litter mulch (LM) and untreated trail (U) were applied on newly established machine operating trails subjected to low, medium, and high machine traffic intensity classes and compared to the undisturbed area (i.e., control; UND). Approximately 22 months after ground-based machine traffic and mulching application, seeds of Caucasian alder were sown in each treatment and in the undisturbed area and further extracted after the first growing season to assess their growth rates. Three years after applying mulch on the compacted soil, recovery values of soil physical and chemical properties (with the exception of soil C/N ratio) in all traffic intensities were significantly higher in LM than SM, compared to U treatment. Nevertheless, recovery values of soil physical and chemical properties were still higher than values in UND area over a 3-year period. All the measured growth and biomass responses of Caucasian alder seedlings changed significantly with increasing traffic intensities (all P ≤ 0.05). Significantly higher seed germination percentage was recorded in LM with low traffic intensity (54%). Significantly higher seedling stem height (17.3 cm), main root length (23.6 cm), seedling total (7.68 g), shoot (2.87 g), and root dry (4.81 g) biomass were observed in the UND area followed by LM with low traffic ≈ LM with medium traffic treatments, whereas the lowest values of seedling size and biomass were detected on U with low, medium, and high traffic intensities. Seedling root mass ratio (RMR; 61%) and root to shoot ratio (R/S; 1.89) were greatest in the UND area, while the RMR (40%) and R/S (0.86) were least in the U plots with high traffic intensity. We can conclude that the highest seedling growth, biomass, and allocation ratios and favorable soil physical, chemical, and bio-chemical properties can be attributed to UND, LM with low and medium traffic, and SM with low traffic treatments. [ABSTRACT FROM AUTHOR]

Information about nutrient dynamics is of upmost importance in order to contribute to the restoration of degraded forest environments in the Andes of southern Ecuador. This study aims to investigate the differences of nutrient dynamics between a native alder (Alnus acuminata) and an exotic pine (Pinus patula) tree species in this region. Based on litterfall, forest floor and mineral topsoil (0–20 cm) of two pine and two alder plantations, we studied the litterfall production and its seasonality; temporal variations of nutrient concentrations, stoichiometric ratios and potential nutrient return (PNR) of leaf-litterfall; mean residence times (MRT) of nutrients in the forest floor; and assessed soil biogeochemical properties. Our results showed that total litterfall production in pine was twice as high as in alder. Litterfall biomass seasonality was similar for both species and highly associated to periods with less precipitation. Pine exhibited the highest seasonality of nutrient concentrations and stoichiometric ratios. PNR of N, K, Ca, and Mn exhibited the major differences between the species. The annual PNR of N and Ca were higher in alder, while those of K and Mn were higher in pine. Pine exhibited higher MRT values for C, N, P, S, Cu, and Zn, while alder showed the higher for Mg, K, Mn, and Ca. In soils, alder exhibited higher concentrations and stocks of nutrients, but not for C. Although, the soil microbial biomass was similar under both species, microbial activity was different. C and net N mineralization were higher in alder, and nitrification dominated over ammonification processes. In general, our findings show a faster cycling of nutrients in alder than in pine. [ABSTRACT FROM AUTHOR]

Arsenic (As) is a toxic metalloid common in coal mining soils. We evaluated a stratification treatment of 48 h of chilling imbibition (3 °C) versus control imbibition (25 °C) in seeds of the Andean tree Alnus acuminata (Kunth). Five concentrations of As: 0, 2.5, 5.0, 7.5, and 10 mg L−1 were tested in both groups of seeds to determine whether chilling imbibition affects the germination, vigor of seedlings and tolerance to arsenic. Physiological, biochemical and morphometric traits were evaluated in germinants to establish how chilling imbibition and As modulate the early development. Growth and tolerance index were estimated in seedlings of 70 days. We found that chilling imbibition enhanced the germination tolerance to arsenic and this effect was unaltered by its concentration. The germinants accumulated arsenic and the maximum reduction of growth was around 28%, but these germinants reached the stage of seedling without negative affectations in final size or biomass. The emergence of the first leaf was delayed in germinants coming from seeds imbibed at 25 °C and exposed to As. Chilling imbibition increased the allometric relationship between size and biomass in germinants exposed to As, improving the vigor and tolerance in more than 55%. Our results suggest that accumulation of As in cotyledons, a high content of carbohydrates and proteins, the activity of SOD, POX and probably the synthesis of phytochelatins are the strategies of tolerance in germinants coming from pre-chilled seeds. This treatment becomes important for the implementation of A. acuminata in forestry programs for soils affected by coal mining. [ABSTRACT FROM AUTHOR]

Nutrient resorption (NR) from senescing leaves plays an important role in the conservation of nutrients in plants. The nutrient resorption efficiency depends on several factors including availability of soil nutrients, species type and leaf nutrient quality. Although several researchers have worked on the pattern of NR in deciduous and evergreen plants, it varied widely. Since the variations are species-specific and many functional groups prevailing in tropical and subtropical forests have not been studied, the understanding of NR pattern in varied functional groups remained incomplete. In this study, Nitrogen resorption efficiency (NRE) of four tree species belonging to different functional groups viz., Alnus nepalensis (non-leguminous nitrogen-fixing and deciduous), Lithocarpus dealbatus (broadleaved and evergreen), Pinus kesiya (coniferous and evergreen) and Schima wallichii (broadleaved semi-evergreen) were studied. NRE was greatest in Alnus nepalensis and Schima wallichii immediately before the maximum leaf fall and it decreased in the subsequent months. However, NRE in Lithocarpus dealbatus exhibited identical values across all the months in a year. In Pinus kesiya, the NRE was the lowest and it varied through six months. The nitrogen concentration in the leaves and NRE varied significantly among the species and across the months. The trees belonging to certain functional groups did not differ in their NREs in different months of a year due to the availability of alternate strategies to acquire nitrogen or being semi-/ evergreen in nature to cope up with their nutrient loss. [ABSTRACT FROM AUTHOR]