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The spread of ecosystem modifying invasive plant (EMIP) species is one of the largest threats to native ecosystems in Hawaiʻi. However, differences in niche characteristics between Hawaiʻi's isolated insular environment and the wider global distribution of these species have not been carefully examined. We used species distribution modeling (SDM) methods to assess similarities and differences in niche characteristics between global and regional scales for 17 EMIPs present in Hawaiʻi. With a clearer understanding of the global context of regional plant invasion, we combined two SDM methods to better understand the potential future regional spread: (1) a nested modeling approach to integrate global and regional invasive species distribution projections; and (2) integrating all available agency and citizen science data to minimize the effect of monitoring gaps and biases. Our results show there are multiple similarities in niche characteristics across regional and global scales for most species, such as similar sets of climatic determinants of distribution, similar responses along environmental gradients, and moderate to high niche overlap between global and regional models. However, some differences were apparent and likely due to several factors including incomplete regional spread, community assembly or diversity effects. Invaders that established earlier showed a higher degree of niche overlap and similar environmental gradient responses when comparing global and regional models. This pattern, coupled with the tendency for regionally-based projections to predict narrower distributions than global projections, indicates a potential for continued spread of several invasive species across the Hawaiian landscape. Our study has broader implications for understanding the distribution and spread of invasive species in other regions, as similar analyses and models, including a novel way to characterize environmental gradient response differences across regions or scales, can likely provide valuable information for conservation and management efforts. [ABSTRACT FROM AUTHOR]

DRIFT (Downstream Response to Imposed Flow Transformation) is an interactive, ecological-social process and software package to assist with environmental flow assessments and river management decision-making. It was originally developed in the 1990s and has subsequently evolved and been applied in over 50 studies in Africa, South America, Asia and Europe. Early versions provided predicted ecological responses over time to specific flow changes, while the latest version provides responses to flow and non-flow drivers as seasonal time series. Here, an ecosystem or eco-social network is built for the river, with links between driver and responder indicators, and relationships created for each link. The network and relationships are developed and entered into the software by specialists based on available data and their knowledge. A range of scenarios is explored through the predicted indicator time series, discipline and site level ecological integrity, and social well-being. While DRIFT models vary in complexity, they are all based on relatively simple fundamental principles and arithmetic. Sequential averaging and summation through the system network is used to calculate an indicator's response to different drivers for successive seasons over time, while the discipline and site level summaries are found using weighted summation of indicator results and individual discipline results, respectively. Information from different specialist areas is therefore processed in the same way, thereby enabling coherent integration across disciplines. [ABSTRACT FROM AUTHOR]

This paper presents the application of an exponential version of the harmonic balance method to the analysis of steady state vibration of geometrically nonlinear systems. A detailed description of the method and of the corresponding numerical procedure is provided. The von Karman theory is used to describe the effects of geometric nonlinearity. The material of the beams is modelled with the help of the Zener model using the fractional calculus. The problem is solved using an exponential version of the harmonic balance method. In the above-mentioned version, the complex calculus is used in contrast to the ordinary harmonic balance method, where the steady state vibrations are described with the help of the trigonometric functions. It significantly simplifies derivation of the amplitude equations. Moreover, the exponential version of the harmonic balance method is more elegant in comparison with the ordinary one. A detailed derivation of the amplitude equations is presented. The modified continuation method is proposed to solve the nonlinear amplitude equations and to determine the response curves. Moreover, the results of the exemplary calculation are presented and compared with known results in order to justify the efficiency and the correctness of the proposed approach. [ABSTRACT FROM AUTHOR]

Environmental variation within a species' range can create contrasting selective pressures, leading to divergent selection and novel adaptations. The conservation value of populations inhabiting environmentally marginal areas remains in debate and is closely related to the adaptive potential in changing environments. Strong selection caused by stressful conditions may generate novel adaptations, conferring these populations distinct evolutionary potential and high conservation value under climate change. On the other hand, environmentally marginal populations may be genetically depauperate, with little potential for new adaptations to emerge. Here, we explored the use of ecological niche models (ENMs) linked with common garden experiments to predict and test for genetically determined phenotypic differentiation related to contrasting environmental conditions. To do so, we built an ENM for the alpine plant Silene ciliata in central Spain and conducted common garden experiments, assessing flowering phenology changes and differences in leaf cell resistance to extreme temperatures. The suitability patterns and response curves of the ENM led to the predictions that: (1) the environmentally marginal populations experiencing less snowpack and higher minimum temperatures would have delayed flowering to avoid risks of late‐spring frosts and (2) those with higher minimum temperatures and greater potential evapotranspiration would show enhanced cell resistance to high temperatures to deal with physiological stress related to desiccation and heat. The common garden experiments revealed the expected genetically based phenotypic differentiation in flowering phenology. In contrast, they did not show the expected differentiation for cell resistance, but these latter experiments had high variance and hence lower statistical power. The results highlight ENMs as useful tools to identify contrasting putative selective pressures across species ranges. Linking ENMs with common garden experiments provides a theoretically justified and practical way to study adaptive processes, including insights regarding the conservation value of populations inhabiting environmentally marginal areas under ongoing climate change. [ABSTRACT FROM AUTHOR]

Description of the subject. This study evaluates the application of Boosted Regression Trees (BRT) for predicting beech dominant height in the Hyrcanian forests of Iran, inscribed as a UNESCO’s World Heritage due to its remarkable biodiversity. Objectives. It is widely accepted that tree growth can be influenced by a wide variety of factors such as climate, topography, soil conditions and competition for resources. The early dominant height of trees modelling studies used the multiple linear regression. The development of more advanced non-parametric and machine learning methods provided opportunities to overcome the nonlinear relationships in forest ecosystems. Method. In this study, boosted regression trees was evaluated to model the dominant height of Fagus orientalis as the most important tree species in the Hyrcanian forest, Iran. Dominant height was related to soil and topographical variables, which are available for 190 sample plots covering all importance environmental gradients in the research area. Results. The results indicated BRT were found to outperform for modelling beech dominant height. This technique showed that phosphorus, percentage nitrogen, magnesium and percentage sand were among the most important variables. Conclusions. This study demonstrates the ability of BRT to accurately model the dominant height of oriental beech in relation to environmental predictors, and encourages its use in forest ecology.

Giant hogweed is a globally invasive plant that can cause a phototoxic reaction which can cause burns and hyperpigmentation. As a result, the species can have large economic costs and human health impacts where high plant densities and high human densities overlap. The invasion, however, is relatively slow moving, which may lead to an underestimate of potential range and impact. We use life history data to construct Maxent and logistic regression models of potential range in North America. These models suggest that the core areas of high habitat suitability overlap with high human population density, but that most of these areas have already been invaded. There is, however, scope for further spread in areas adjacent to the core, and in novel, less populated, mountainous and maritime locations. [ABSTRACT FROM AUTHOR]

A considerable multitude of chemiresistive type of gas sensors has been estimated to sense minute amounts of hazardous or toxic gases using inexpensive setups. Although the ultimate value of the response of gas sensors is well-established, analyzing other characteristics has been mostly neglected. In the present paper, we demonstrate the modeling of time-dependent responses by slightly modified Gompertz functions whose derived parameters can be correlated with the detection mechanism, thus, expanding analysis methods towards a better understanding of gas sensing. [ABSTRACT FROM AUTHOR]

Species distribution models are generic empirical techniques that have a number of applications. One of these applications is to determine which environmental conditions are most important for a species. The calculation of this variable importance depends on a number of assumptions, including that the observations that are used to estimate the models are independent of each other. Spatial autocorrelation, which is a common feature most environmental factors confounds this assumption. Besides, many species distribution models are trained using a number of explanatory variables that have different levels of spatial autocorrelation. In this study we quantified the effects of differences in spatial autocorrelation in explanatory variables and the type of species responses to environmental gradients on variable importance estimations in species distribution models. We simulated data for both environmental predictors and species, so that we were in control of the true contribution of every variable in the model and the importance that could be estimated after fitting the models. We found that spatial autocorrelation in the predictors inflated the variable importance estimates, but only when the response of species to the environmental gradients is linear. This inflation effect was larger when the environmental preferences of species coincided with the dominant environmental conditions in a study site. Additionally we find that unimodal responses to the predictors yield systematically a higher variable importance compared to linear responses. We conclude that the type of response to environmental conditions and the relative levels of spatial autocorrelation in the environmental variables cause most bias in relative variable importance estimations. In this way, this study helps to clarify in a systematic and controlled approach how to make proper inferences about variable importance in species distribution models. [ABSTRACT FROM AUTHOR]

The current trend of increasing input of terrestrially derived dissolved organic carbon (DOC) to boreal freshwater systems is causing increased levels of carbon dioxide (CO2) supersaturation and degassing. Phosphorus (P) is often the most limiting nutrient for bacterial growth and would thus be expected to increase overall mineralization rates and CO2 production. However, high carbon (C) to P ratios of terrestrially derived DOC could also cause elevated cell-specific respiration of the excess C in heterotrophic bacteria. Using data from a survey of 75 Scandinavian lakes along an ecosystem gradient of DOC, we estimated in situ CO2 production rates. These rates showed a unimodal response with DOC-specific CO2 production negatively related to DOC:total phosphorus (TP) ratio, and a turning point at 5 mg C L−1, indicating higher DOC turnover rates in productive than in unproductive lakes. To further assess the dependency of bacterial respiration (BR) on DOC and P, we monitored CO2 production in incubations of water with a gradient of DOC crossed with two levels of inorganic P. Finally, we crossed DOC and P with a temperature gradient to test the temperature dependency of respiration rates [as oxygen (O2) consumption]. While total CO2 production seemed to be unaffected by P additions, respiration rates, and growth yields, as estimated by ribosomal gene copy numbers, suggest increased bacterial growth and decreased cell-specific respiration under non-limited P conditions. Respiration rates showed a sigmoid response to increasing DOC availability reaching a plateau at about 20 mg C L−1 of initial DOC concentrations. In addition to these P and DOC level effects, respiration rates responded in a non-monotonic fashion to temperature with an increase in respiration rates by a factor of 2.6 (±0.2) from 15 to 25°C and a decrease above 30°C. The combined results from the survey and experiments highlight DOC as the major determinant of CO2 production in boreal lakes, with P and temperature as significant modulators of respiration kinetics.

An effective strategy for the analysis and comparison of profiles is proposed and illustrated with case studies. This useful strategy makes effective use of profile data by using all the data in each individual profile to create two statistics that describe the profile behavior: Profile "Level" and Profile "Shape." The profile Level relates to the area under the profile. The Shape statistic is related to the rate of increase of the profile over time. These characteristics enable practical interpretations regarding the factors studied in the experiment. The method is easy to use requiring only straight line regression and design of experiments analysis procedures. A Modified Principal Component Analysis is recommended as an alternative approach to create profile level and shape statistics when the linearized profile model does not give an adequate description of the data. [ABSTRACT FROM AUTHOR]

The current trend of increasing input of terrestrially derived dissolved organic carbon (DOC) to boreal freshwater systems is causing increased levels of carbon dioxide (CO2) supersaturation and degassing. Phosphorus (P) is often the most limiting nutrient for bacterial growth and would thus be expected to increase overall mineralization rates and CO2 production. However, high carbon (C) to P ratios of terrestrially derived DOC could also cause elevated cell-specific respiration of the excess C in heterotrophic bacteria. Using data from a survey of 75 Scandinavian lakes along an ecosystem gradient of DOC, we estimated in situ CO2 production rates. These rates showed a unimodal response with DOC-specific CO2 production negatively related to DOC:total phosphorus (TP) ratio, and a turning point at 5 mg C L−1, indicating higher DOC turnover rates in productive than in unproductive lakes. To further assess the dependency of bacterial respiration (BR) on DOC and P, we monitored CO2 production in incubations of water with a gradient of DOC crossed with two levels of inorganic P. Finally, we crossed DOC and P with a temperature gradient to test the temperature dependency of respiration rates [as oxygen (O2) consumption]. While total CO2 production seemed to be unaffected by P additions, respiration rates, and growth yields, as estimated by ribosomal gene copy numbers, suggest increased bacterial growth and decreased cell-specific respiration under non-limited P conditions. Respiration rates showed a sigmoid response to increasing DOC availability reaching a plateau at about 20 mg C L−1 of initial DOC concentrations. In addition to these P and DOC level effects, respiration rates responded in a non-monotonic fashion to temperature with an increase in respiration rates by a factor of 2.6 (±0.2) from 15 to 25°C and a decrease above 30°C. The combined results from the survey and experiments highlight DOC as the major determinant of CO2 production in boreal lakes, with P and temperature as significant modulators of respiration kinetics. [ABSTRACT FROM AUTHOR]

In this paper, a novel fault localization method combining frequency response analysis (FRA) and evidential reasoning process is proposed. FRA test is conducted at first so that we can obtain corresponding responses of several monitoring nodes on the winding. Traditional FRA interpretation methods simply compares those response curves, while in our work, evidential reasoning method is adopted to present beliefs about the fault locations. Extracted features from monitoring sensors are mapped into deviation matrix by which possibility assignments of each fault location is computed. So we finally obtain fault distribution probabilities. According to test calculation results, proposed method can give fault probabilities of each section of transformer winding, which correctly indicate the fault position.

In this paper, a novel fault localization method combining frequency response analysis (FRA) and evidential reasoning process is proposed. FRA test is conducted at first so that we can obtain corresponding responses of several monitoring nodes on the winding. Traditional FRA interpretation methods simply compares those response curves, while in our work, evidential reasoning method is adopted to present beliefs about the fault locations. Extracted features from monitoring sensors are mapped into deviation matrix by which possibility assignments of each fault location is computed. So we finally obtain fault distribution probabilities. According to test calculation results, proposed method can give fault probabilities of each section of transformer winding, which correctly indicate the fault position. [ABSTRACT FROM AUTHOR]

Abstract Understanding invasive species distributions and potential invasions often requires broad‐scale information on the environmental tolerances of the species. Further, resource managers are often faced with knowing these broad‐scale relationships as well as nuanced environmental factors related to their landscape that influence where an invasive species occurs and potentially could occur. Using invasive buffelgrass (Cenchrus ciliaris), we developed global models and local models for Saguaro National Park, Arizona, USA, based on location records and literature on physiological tolerances to environmental factors to investigate whether environmental relationships of a species at a global scale are also important at local scales. In addition to correlative models with five commonly used algorithms, we also developed a model using a priori user‐defined relationships between occurrence and environmental characteristics based on a literature review. All correlative models at both scales performed well based on statistical evaluations. The user‐defined curves closely matched those produced by the correlative models, indicating that the correlative models may be capturing mechanisms driving the distribution of buffelgrass. Given climate projections for the region, both global and local models indicate that conditions at Saguaro National Park may become more suitable for buffelgrass. Combining global and local data with correlative models and physiological information provided a holistic approach to forecasting invasive species distributions.

Vibration of a blade couple damped by a dry friction contact in the shroud is investigated by means of hysteresis loops and response curves analysis. The studied system is excited by one harmonic external force in a frequency range near to the lowest eigenfrequency of real blades. Blades are connected by means of a damping element consisting of dry friction part linked in series with linear spring. This "stick-slip" damping element is supposed to be either weightless or of a very small mass which models the mass of elastically deformed parts of contacting bodies near the friction surface. Two approximate mathematical models of "stick-slip" dry friction elements are suggested and analysed. The response curves of blade couple connected by stick-slip damping element are presented for different values of slip friction forces and two values of mass of elastically deformed parts.

The importance of considering species-specific biotic interactions when predicting feedbacks between the effects of climate change and ecosystem functions is becoming widely recognised. The responses of soil animals to predicted changes in global climate could potentially have far-reaching consequences for fluxes of soil carbon, including climatic feedbacks resulting from increased emissions of carbon dioxide from soils. The responses of soil animals to different microclimates can be summarised as norms of reaction, in order to compare phenotypic differences in traits along environmental gradients. Thermal and moisture reaction norms for physiological, behavioural and life history traits of species of terrestrial isopods differing in their morphological adaptations for reducing water loss are presented. Gradients of moisture reaction norms for respiratory rates and thermal reaction norms for water loss, for a species from the littoral zone were steeper than those for species from mesic environments. Those for mesic species were steeper than for those from xeric habitats. Within mesic species, gradients of thermal reaction norms for aggregation were steeper for Oniscus asellus than for Porcellio scaber or Armadillium vulgare, and moisture reaction norms for sheltering and feeding behaviours were steeper for Philoscia muscorum than for either P. scaber or A. vulgare. These differences reflect differences in body shape, permeability of the cuticle, and development of pleopodal lungs. The implications of differences between different species of soil animals in response to microclimate on the possible influence of the soil fauna on soil carbon dynamics under future climates are discussed. In conclusion a modelling approach to bridging the inter-disciplinary gap between carbon cycling and the biology of soil animals is recommended. [ABSTRACT FROM AUTHOR]

Understanding invasive species distributions and potential invasions often requires broad‐scale information on the environmental tolerances of the species. Further, resource managers are often faced with knowing these broad‐scale relationships as well as nuanced environmental factors related to their landscape that influence where an invasive species occurs and potentially could occur. Using invasive buffelgrass (Cenchrus ciliaris), we developed global models and local models for Saguaro National Park, Arizona, USA, based on location records and literature on physiological tolerances to environmental factors to investigate whether environmental relationships of a species at a global scale are also important at local scales. In addition to correlative models with five commonly used algorithms, we also developed a model using a priori user‐defined relationships between occurrence and environmental characteristics based on a literature review. All correlative models at both scales performed well based on statistical evaluations. The user‐defined curves closely matched those produced by the correlative models, indicating that the correlative models may be capturing mechanisms driving the distribution of buffelgrass. Given climate projections for the region, both global and local models indicate that conditions at Saguaro National Park may become more suitable for buffelgrass. Combining global and local data with correlative models and physiological information provided a holistic approach to forecasting invasive species distributions. [ABSTRACT FROM AUTHOR]

For answering the growing demand of innovative micro-fluidic devices able to measure the refractive index of samples in extremely low volumes, this paper presents an overview of the performances of a micro-opto-fluidic sensing platform that employs rectangular, miniature hollow glass tubings. The operating principle is described by showing the analytical model of the tubing, obtained as superposition of different optical cavities, and the optical readout method based on spectral reflectivity detection. We have analyzed, in particular, the theoretical and experimental optical features of rectangular tubings with asymmetrical geometry, thus with channel depth larger than the thickness of the glass walls, though all of them in the range of a few tens of micrometers. The origins of the complex line-shape of the spectral response in reflection, due to the different cavities formed by the tubing flat walls and channel, have been investigated using a Fourier transform analysis. The implemented instrumental configuration, based on standard telecom fiberoptic components and a semiconductor broadband optical source emitting in the near infrared wavelength region centered at 1.55 µm, has allowed acquisition of reflectivity spectra for experimental verification of the expected theoretical behavior. We have achieved detection of refractive index variations related to the change of concentration of glucose-water solutions flowing through the tubing by monitoring the spectral shift of the optical resonances. [ABSTRACT FROM AUTHOR]

Context: Biological invasions are characterized by dynamic spatiotemporal distribution patterns. Yet landscape scale distribution patterns of invasive species are rarely leveraged to understand invasion in a comprehensive manner. Objectives: Characterize three key stages of invasion from the landscape scale distribution patterns for an invasive insect-Asian citrus psyllid ( Diaphorina citri), and investigate the potential spatial variability in establishment and impact risk. Methods: The study focuses on the recent invasion of D. citri in Southern California's urban landscape. We used a combination of spatiotemporal pattern analyses and species distribution models (SDMs) to characterize the introduction, establishment and impact of D. citri invasion. Results: Diaphorina citri detections in relation to major roadways revealed that initial detections are significantly closer to major roads than later detections, suggesting that transportation corridors serve as introduction pathways. SDMs of D. citri establishment and impact potential using presence-(pseudo)absence and abundance revealed percent impervious surface as the best landscape predictor. Inclusion of prior D. citri detections as a lagged spatiotemporal effect improved both model fit and performance suggesting that small-scale dispersal events do matter. Interestingly, interpolated risk maps based on the predicted occurrence and abundance highlighted substantial spatial variability in D. citri establishment and impact risk. Conclusion: Our study demonstrates how examining spatiotemporal patterns of an invasive species is useful in inferring key stages of the invasion, and how occurrence and abundance information can be leveraged to quantify variability in establishment and impact risk. The study thus provides a useful baseline in formulating effective landscape-level management actions. [ABSTRACT FROM AUTHOR]

The paper is devoted to non-linear vibrations of plates, made of the Zener viscoelastic material modelled with the Caputo fractional derivative, and in particular to their response to harmonic excitation. The plate geometric non-linearity is of the von Kármán type. In the formulation shear effects and rotary inertia are considered, too. The problem is solved in the frequency domain. A one-harmonic form of the solution for plate displacements corresponding to the plate formulation is assumed. The amplitude equation is obtained from the time averaged principle of virtual work. The time averaging precedes the use of the harmonic balance method. In the space discretization the finite element method is used involving 8-noded rectangular plate elements with selective-reduced integration. Several numerical examples are analyzed and the response curves are found using a path-following method. The purpose of these analyses is to identify material features of the adopted model of viscoelasticity with the fractional derivative. [ABSTRACT FROM AUTHOR]

The present work examines the hydrodynamic flow pattern in an industrial tubular baromembrane device on the example of commercially available membrane elements at pressures of 1.0-4.0 MPa. Experimental response curves and dependence curves of the longitudinal mixing coefficient were obtained as a function of the solution flow rate and the pressure in the membrane module. Based on this information, the criterial equation for calculating the longitudinal mixing coefficient was obtained. Numerical values of empirical coefficients are given, which can theoretically be used to calculate the longitudinal mixing coefficients as well as to predict the values for similar constructions of baromembrane systems operating at high transmembrane pressures. [ABSTRACT FROM AUTHOR]

Von Kármán geometrically nonlinear plates, made of the Zener viscoelastic material, subjected to harmonic excitation are analyzed in this paper. Shear effects and the influence of rotary inertia are included. The problem is formulated in the frequency domain, starting with the time-averaged principle of virtual work. An appropriate harmonic form of the solution for plate displacements is assumed. The amplitude equation is obtained with the use of time averaging followed by the harmonic balance method. Then, the finite element discretization is adopted using 8-noded rectangular plate elements with selective-reduced integration. Some numerical examples are solved, and the response curves are found using a path-following method. Focus in these analyses is laid on checking the material features resulting from the proposed combination of geometric nonlinearity and the adopted model of viscoelasticity. [ABSTRACT FROM AUTHOR]

Modeling the distribution and habitat capacities of key estuarine species can be used to identify hot spots, areas where species density is significantly higher than surrounding areas. This approach would be useful for establishing a baseline for evaluating future environmental scenarios across a landscape. We developed species distribution models for early juvenile life stages of brown shrimp ( Farfantepenaeus aztecus), white shrimp ( Litopenaeus setiferus), blue crab ( Callinectes sapidus), and spotted seatrout ( Cynoscion nebulosus) in order to delineate the current coastal hot spots that provide the highest quality habitat conditions for these estuarine-dependent species in Louisiana. Response curves were developed from existing long-term fisheries-independent monitoring data to identify habitat suitability for fragmented marsh landscapes. Response curves were then integrated with spatially explicit input data to generate species distribution models for the coastal region of Louisiana. Using spatial autocorrelation metrics, we detected clusters of suitable habitat across the Louisiana coast, but only 1% of the areas were identified as true hot spots with the highest habitat quality for nekton. The regions identified as hot spots were productive fringing marsh habitats that are considered the most vulnerable to natural and anthropogenic impacts. The species distribution models identify the coastal habitats which currently provide the greatest capacity for key estuarine species and will be used in the Louisiana coastal planning process to evaluate how species distributions may change under various environmental and restoration scenarios. [ABSTRACT FROM AUTHOR]

Nocturnal rodents play a key role in the Sonoran Desert ecosystem as consumers, prey and reservoirs of disease-yet rodent distribution remains poorly mapped. We use surface temperature extracted from the Landsat Thematic Mapper thermal infrared band to model rodent abundance obtained from trapping data at the Organ Pipe Cactus National Monument in southwest Arizona. We produce response curves that describe the effects of surface temperature on species abundance. Daytime surface temperature derived from images collected in June across thirty rodent trapping grids ranged from 318 K (45.0 °C) to 332 K (59.2 °C). Results show peak seasonal surface temperature splits high species abundances into two groups: Merriam's kangaroo rat, Arizona pocket mouse, desert pocket mouse and southern grasshopper mouse species prefer habitat characterized by higher surface temperatures; and white-throated wood rat, cactus mouse, rock pocket mouse and Bailey's pocket mouse species prefer habitat characterized by lower temperatures. Abundances for the high and low temperature habitat groupings correlate linearly with surface temperature (r = +0.66 and −0.75, respectively, p < 0.001). Surface temperature integrates multiple landscape characteristics (e.g. topography, vegetation cover and soil properties) that define the dominant habitats of ORPI rodents. These results prove that simple models can inform complex ecological processes. [ABSTRACT FROM AUTHOR]

Forests are expected to expand into alpine areas due to global climate change. It has recently been shown that temperature alone cannot realistically explain this process and that upslope tree advance in a warmer scenario may depend on the availability of sites with adequate geomorphic/topographic characteristics. Here, we show that, besides topography (slope and aspect), climate itself can produce a braking effect on the upslope advance of subalpine forests and that tree limit is influenced by non-linear and non-monotonic contributions of the climate variables which act upon treeline upslope advance with varying relative strengths. Our results suggest that global climate change impact on the upslope advance of subalpine forests should be interpreted in a more complex way where climate can both speed up and slow down the process depending on complex patterns of contribution from each climate and non-climate variable. [ABSTRACT FROM AUTHOR]

The bird species distribution along a dry forest-oak woodland vegetation gradient was studied in autumn and spring in two consecutive years. Intra-seasonal comparisons showed that bird species had similar distributions in each of the two years. Inter-seasonal changes were mainly due to compositional differences even though resident species generally used similar habitats in both seasons. Ordination analyses, based on the first year bird species abundances, showed a clearly segregated distribution between forest and woodland birds. Within these two vegetation types, the distribution tended to be more individualistic. Nevertheless further habitats could be identified according to groups of birds having similar distributions. These habitats did not correspond to the plant associations which resulted from a previous classification of the vegetation. Observations of the plant use by the birds during the study period showed that, in most cases, the plant variables associated with ordination analyses are unlikely to be very important for the bird species life cycles. Rev. Biol. Trop. 54(2): 657-672. Epub 2005 Jun 01.Se estudió la distribución de especies de aves a lo largo de un gradiente de vegetación bosque seco - bosque de encino en el otoño y primavera de dos años consecutivos. Las comparaciones intra-estacionales mostraron distribuciones similares de las especies de aves en ambos años. Los cambios inter-estacionales se debieron principalmente a diferencias en la composición, aunque las especies residentes normalmente usan hábitats similares en ambas estaciones. Los análisis de ordenación, basados en las abundancias de las aves en el primer año de muestreo, mostraron una distribución claramente segregada entre aves del bosque seco y del bosque de encino. Aunque la distribución de las especies fue más azarosa dentro de cada tipo de vegetación, se pudieron identificar ciertos hábitats en base a grupos de aves con distribuciones similares. Estos hábitats no correspondieron con las asociaciones vegetales identificadas. Las observaciones del uso de las plantas durante el período de estudio sugieren, en la mayoría de los casos, que las variables vegetales asociadas con los ejes de ordenación no serían muy importantes para el ciclo de vida de las especies de aves. Sin embargo, se requiere investigación adicional para comprender su verdadera función.

The results of experimental research on hydrodynamics of solution flow in membrane channel are reported. Response curves correlating flow pattern with solution flow rate, pressure, and type of membrane module are obtained. A theoretical analysis of the research results is made with a description of the response curves using criterial equations that correlate empirical coefficients with solution flow rate in the channel, pressure, and type of membrane elements. [ABSTRACT FROM AUTHOR]

The hydrodynamics of flow structure in an industrial spiral reverse-osmosis device has been studied using as an example commercially available membrane elements ERO-E-6.5/900A and ERO-K-92-475 at operating pressures of 1.0 to 4.0 MPa. Experimental data on response curves and the axial mixing coefficient depending on the flow rate of the solution and pressure in the separation module have been obtained, thus making it possible to derive a criterion equation for calculating axial mixing coefficients. Numerical values for empirical factors are reported by which axial mixing coefficients can be calculated and their values be predicted for similar membrane units operating at a high hydrostatic pressure. [ABSTRACT FROM AUTHOR]

Spatial irrigation of agricultural crops using site-specific variable-rate irrigation (VRI) systems is beginning to have widespread acceptance. However, optimizing the management of these VRI systems to conserve natural resources and increase profitability requires an understanding of the spatial crop responses. In this research, we utilize a recently developed spatially explicit analysis model to reanalyze spatial corn yield data. The specific objectives of this research were to (1) calculate a suite of estimates (estimated yield, rainfed yield, maximum yield, and irrigation at maximum yield) and provide credible intervals (measures of uncertainty) around these estimates for comparing with the previous analysis, and (2) examine whether the conclusions from this rigorous re-analysis were different from the prior analysis and if the results would force any modifications to the conclusions obtained with the prior analyses. The spatially explicit analysis was achieved using a mixed model formulation of bivariate penalized smoothing splines and was implemented in a Bayesian framework. This model simultaneously accounted for spatial correlation as well as relationships within the treatments and had the ability to contribute information to nearby neighbors. The model-based yield estimates were in excellent agreement with the observed spatial corn yields and were able to estimate the high and low yields more accurately than the previous analysis. Credible intervals were calculated around the estimates, and the majority encompassed the observed yields. After calculating estimates of yield, we then calculated estimates of other response variables, such as rainfed yield, maximum yield, and irrigation at maximum yield. These estimated response variables were then compared with previous results from a classical statistical analysis. Our conclusions supported the original analysis in identifying significant spatial differences in crop responses across and within soil map units. These spatial differences were great enough to be considered in irrigation system design and management. The major improvement in the 2014 re-analysis is that the model explicitly considered spatial dependence in calculating the estimated yields and other variables and thus should provide improved estimates of the impact of spatial differences for use in irrigation system design and management. [ABSTRACT FROM AUTHOR]

Radio Frequency Identification (RFID) is a new generation of automatic identification technology, and has been widely applied in the production, management, life and other fields. Traditional RFID tags based on integrated circuit chip to identify the number. It is hard to read information in the metal objects, liquid, strong electromagnetic interference environment and high temperature environment. RFID technology based on SAW arises at the historic moment, the two are competitive and complementary in the market and technology. The SAW tags in the RFID system, and is composed of the piezoelectric substrate, interdigital transducer (IDT), the reflector and antenna. The article analyzed the overall structure of SAW RFID tag, used the L-edit software to design and draw the IDT and reflector of SAW RFID tags. According to different encoding methods of reflector response curves were simulated. Finally, the article analyzed and compared the advantages and disadvantages of different codings, and at last chose SPUDT collinear structure. This kind of passive RFID tag as new achievements is a collection of modern electronics, acoustics, microelectronics technology and radar signal processing technologies, it has to adapt to bad environment, wireless passive, far distance identification and low production cost. It is a complements of the existing IC chip tag on the function. [ABSTRACT FROM AUTHOR]

Vibration of a blade couple damped by a dry friction contact in the shroud is investigated by means of hysteresis loops and response curves analysis. The studied system is excited by one harmonic external force in a frequency range near to the lowest eigenfrequency of real blades. Blades are connected by means of a damping element consisting of dry friction part linked in series with linear spring. This ''stick-slip'' damping element is supposed to be either weightless or of a very small mass which models the mass of elastically deformed parts of contacting bodies near the friction surface. Two approximate mathematical models of ''stick-slip'' dry friction elements are suggested and analysed. The response curves of blade couple connected by stick-slip damping element are presented for different values of slip friction forces and two values of mass of elastically deformed parts. [ABSTRACT FROM AUTHOR]

Peatlands, with organic soils, are usually dominated by one or a few species. Above and belowground ecological processes are regulated by the characteristics of the dominant species in the peat. Understanding how these species relate to climatic or water chemistry gradients will help to predict the fate of those ecosystems under current climate change. The patterns of abundance and occurrence of 12 major peat-forming species from different structural plant groups were quantified along gradients of elevation, precipitation, and water chemistry. The species were distributed in four major structural groups: cushion plants, true mosses, sedges, and Sphagnum mosses. A response curve for each species was built with Generalized Additive Models. Niche breadths, species tolerances, and species optima were estimated using bootstrap resampling. Our results showed that species were limited in their elevational ranges; Sphagnum species were biased toward low to intermediate elevations, sedges, and true mosses to intermediate elevations and cushion plants to very high elevations. Sphagnum species were more likely to occur in sites with low precipitation, while sedges preferred wet sites. Sphagnum species preferred habitats with acidic pH. The species tolerances and optimum distributions are an indication to the vulnerability of the species to changes in their environment. Species with limited tolerances are more vulnerable, such as the narrow elevational distribution of cushion plants or the low pH and narrow tolerances observed for Sphagnum species. Climate and hydrological changes will very possibly affect the distribution of those species forcing changes on ecosystem functioning. [ABSTRACT FROM AUTHOR]

Abstract: Leeches (Clitellata: Hirudinida) are abundant predators or ecto-parasites inhabiting various freshwater habitats; however many biotic and abiotic drivers of their assemblage patterns have been deduced rather than directly tested. To study species richness and composition changes in leech assemblages, 109 sites of running and stagnant water bodies were sampled in three regions of the Czech Republic in 2007–2010, together with several explanatory variables that are known or expected to be important predictors of leech distribution. In total, 17 species of leeches were recorded, varying between 0–7 and 0–9 species in lotic and lenitic sites, respectively. These differences in species richness of lotic and lenitic sites were highly significant, contrary to the abundances, which varied between 0–283 and 0–295 individuals. The main change in species composition was controlled by water temperature and morphological characteristics (e.g. substrate and cover of macrophytes), mostly reflecting the differences between lotic and lenitic habitats. We found the density of benthos (i.e. prey availability) to be the best predictor of species composition in both lotic and lenitic sites, together with the percentage of canopy cover. However, the other significant predictors (i.e. the substrate and water conductivity found to be significant in lotic sites, and the mean annual temperature and PO4 3− in lenitic sites), differed between these habitats. Other than mean annual temperature and water temperature, which had different effects on species richness in lotic and lenitic sites, there were no other differences between lotic and lenitic sites in terms of how species richness and abundance responded to all other analyzed predictors. Our results stress the importance of prey availability and canopy for leech distribution patterns. Differences in the significant predictors of leech assemblage patterns between lotic and lenitic sites raise fundamental questions about the underlying mechanisms and ecological constraints to leech distribution in these main types of aquatic systems. [Copyright &y& Elsevier]

Intensive use of synthetic nitrogen (N) fertilizers for sugarcane ( Saccharum spp.) production presents environmental challenges for water and air quality as well as impacts profitability for producers. Central to these concerns is a widespread reliance on yield-based recommendations that invoke generic models of crop N response but lack any means to account for variations in soil N-supplying power, a critical determinant of fertilizer N need for cereal, fiber, and tuber crops. The work reported herein was designed to ascertain the impact of soil N mineralization on sugarcane response to N fertilization and was carried out in conjunction with eight N-response trials conducted between 2006 and 2010 at field sites in the largest sugarcane-cultivated area in Brazil. Soil samples were utilized in categorizing the sites as highly responsive, moderately responsive, or nonresponsive to fertilizer N, based on two chemical indices of soil N availability, the Illinois Soil Nitrogen Test (ISNT) and direct steam distillation (DSD), and assessments of (1) net mineralization during aerobic incubation for 12 weeks and (2) incubation-induced changes in soil N fractions obtained by acid (total hydrolyzable N, hydrolyzable NH-N, amino sugar N, and amino acid N) or alkaline (ISNT-N) hydrolysis. Sugarcane varied widely in response to N fertilization, indicating that yield-based recommendations would often under- or overestimate N requirement and thus adversely impact sustainability of sugarcane-based ethanol production. In studies to evaluate feasibility of soil N testing to improve fertilizer N recommendations, mineral N production upon aerobic incubation was accompanied by significant decreases in hydrolyzable NH-N and ISNT-N, indicating that both fractions were liberating mineralizable forms of soil N. Test values by the ISNT and DSD were highly correlated, and both showed promise for differentiating soil responsiveness to fertilizer N. [ABSTRACT FROM AUTHOR]

Pulses of rainfall are particularly pivotal in controlling plant physiological processes in ecosystems controlled by limited water, and the response of desert plants to rainfall is a key to understanding the responses of desert ecosystems to global climatic change. We used a portable photosynthesis system to measure the responses of the diurnal course of photosynthesis, light-response curves, and CO-response curves of two desert shrubs ( Nitraria sphaerocarpa Maxim. and Calligonum mongolicum Turcz) to a rainfall pulse in a desert-oasis ecotone in northwestern China. The photosynthetic parameters, light- and CO-response curves differed significantly before and after the rainfall pulse. Their maximum net photosynthetic rate ( P) values were 23.27 and 32.92 μmol(CO) m s for N. sphaerocarpa and C. mongolicum, respectively, with corresponding maximum stomatal conductance ( g) values of 0.47 and 0.39 mol(HO) m s. The P of N. sphaerocarpa after the rainfall was 1.65 to 1.75 times the value before rainfall, whereas those of C. mongolicum increased to approximately 2 times the prerainfall value, demonstrating the importance of the desert plants response by improving their assimilation rate to precipitation patterns under a future climate. [ABSTRACT FROM AUTHOR]