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Intraguild predation (IGP)–predation between generalist predators (IGPredator and IGPrey) that potentially compete for a shared prey resource–is a common interaction module in terrestrial food webs. Understanding temporal variation in webs with widespread IGP is relevant to testing food web theory. We investigated temporal constancy in the structure of such a system: the spider-focused food web of the forest floor. Multiplex PCR was used to detect prey DNA in 3,300 adult spiders collected from the floor of a deciduous forest during spring, summer, and fall over four years. Because only spiders were defined as consumers, the web was tripartite, with 11 consumer nodes (spider families) and 22 resource nodes: 11 non-spider arthropod taxa (order- or family-level) and the 11 spider families. Most (99%) spider-spider predation was on spider IGPrey, and ~90% of these interactions were restricted to spider families within the same broadly defined foraging mode (cursorial or web-spinning spiders). Bootstrapped-derived confidence intervals (BCI's) for two indices of web structure, restricted connectance and interaction evenness, overlapped broadly across years and seasons. A third index, % IGPrey (% IGPrey among all prey of spiders), was similar across years (~50%) but varied seasonally, with a summer rate (65%) ~1.8x higher than spring and fall. This seasonal pattern was consistent across years. Our results suggest that extensive spider predation on spider IGPrey that exhibits consistent seasonal variation in frequency, and that occurs primarily within two broadly defined spider-spider interaction pathways, must be incorporated into models of the dynamics of forest-floor food webs. [ABSTRACT FROM AUTHOR]

We compared the response to resource enhancement of a simple empirical model of intra‐guild predation (IGP) to the predictions of published, simple mathematical models of asymmetric IGP (a generalist IG Predator that feeds both on a specialist IG Prey and a Resource that it shares with the IG Prey). The empirical model was a food‐web module created by pooling species abundances across many families in a speciose community of soil micro‐arthropods into three categories: IG Predator (large predatory mites), IG Prey (small predatory mites), and a shared Resource (fungivorous mites and springtails). By pooling abundances of species belonging to broadly defined functional groups, we tested the hypothesis that IGP is a dominant organizing principle in this community. Simple mathematical models of asymmetric IGP predict that increased input of nutrients and energy to the shared Resource will increase the equilibrium density of Resource and IG Predator, but will decrease that of IG Prey. In a field experiment, we observed how the three categories of the empirical model responded to two rates of addition of artificial detritus, which enhanced the food of fungivores, the Resource of the IGP module. By the experiment's end, fungivore densities had increased ~1.5× (ratio of pooled fungivore densities in the higher‐input treatment to plots with no addition of detritus), and densities of IG Predators had increased ~4×. Contrary to the prediction of mathematical models, IG Prey had not decreased, but instead had increased ~1.5×. We discuss possible reasons for the failure of the empirical model to agree with IGP theory. We then explore analogies between the behavior of the empirical model and another mathematical model of trophic interactions as one way to gain insights into the trophic connections in this community. We also propose one way forward for reporting comparisons of simple empirical and mathematical models. [ABSTRACT FROM AUTHOR]

PURPOSE: Metastatic castration-resistant prostate cancer (mCRPC) with low androgen receptor (AR) and without neuroendocrine signaling, termed double-negative prostate cancer (DNPC), is increasingly prevalent in patients treated with AR signaling inhibitors and is in need of new biomarkers and therapeutic targets. METHODS: Candidate genes enriched in DNPC were determined using differential gene expression analysis of discovery and validation cohorts of mCRPC biopsies. Laboratory studies were carried out in human mCRPC organoid cultures, prostate cancer (PCa) cell lines, and mouse xenograft models. Epigenetic studies were carried out in a rapid autopsy cohort. RESULTS: Dickkopf-1 (DKK1) expression is increased in DNPC relative to prostate-specific antigen (PSA)–expressing mCRPC in the Stand Up to Cancer/Prostate Cancer Foundation discovery cohort (11.2 v 0.28 reads per kilobase per million mapped reads; q < 0.05; n = 117) and in the University of Washington/Fred Hutchinson Cancer Research Center cohort (9.2 v 0.99 fragments per kilobase of transcript per million mapped reads; P <.0001). DKK1 expression can be regulated by activated Wnt signaling in vitro and correlates with activating canonical Wnt signaling mutations and low PSA mRNA in mCRPC biopsies (P <.05). DKK1 hypomethylation was associated with increased DKK1 mRNA expression (Pearson r = −0.66; P <.0001) in a rapid autopsy cohort (n = 7). DKK1-high mCRPC biopsies are infiltrated with significantly higher numbers of quiescent natural killer (NK) cells (P <.005) and lower numbers of activated NK cells (P <.0005). Growth inhibition of the human PCa model PC3 by the anti-DKK1 monoclonal antibody DKN-01 depends on the presence of NK cells in a severe combined immunodeficient xenograft mouse model. CONCLUSION: These results support DKK1 as a contributor to the immunosuppressive tumor microenvironment of DNPC. These data have provided the rationale for a clinical trial targeting DKK1 in mCRPC (ClinicalTrials.gov identifier: NCT03837353). [ABSTRACT FROM AUTHOR]

While aboveground impacts of invasive plants are well documented, their influence on soil food webs remains less understood. Previous research has revealed that bottom-up forces are widespread in soil food webs of woodlands. Thus, an invasive plant that negatively impacts the base of the food web will likely decrease primary consumers as well as their predators. We examined how a North American plant invader, garlic mustard (Alliaria petiolata), affects arthropod primary (springtails and oribatid mites) and secondary (predaceous mites) consumers of the soil food web via changes to fungal resources. We measured the abundances of plants, soil fungi, fungivores, and predators in garlic mustard-invaded and uninvaded 1-m2 plots in five Midwestern USA woodlands. We then conducted a mesocosm (0.25-m2 plots) experiment to tease apart the direct and indirect effects of garlic mustard by manipulating plant identity (garlic mustard vs. native plant), soil history (invaded vs. uninvaded), and fungicide application (fungicide vs. no fungicide). Our first study revealed that plots without garlic mustard had 2.8 and 1.4 × more fungi and fungivores, respectively. Predator densities did not differ. Fungal composition and structural equation modeling (SEM) revealed the garlic mustard effects on fungivores were correlated with fungal declines. The mesocosm experiment confirmed that the impacts were indirect, as fungicide plots harbored similar fungivore densities, whereas fungivore densities differed according to plant identity and soil history in the fungicide-free plots. Our results reveal that by altering soil fungal abundance, an invasive plant can indirectly affect primary consumers in soil food webs, but this indirect effect does not influence predators. [ABSTRACT FROM AUTHOR]

Arthropods in the leaf litter layer of forest soils influence ecosystem processes such as decomposition. Climate‐change models predict both increases and decreases in average rainfall. Increased drought may have greater impacts on the litter arthropod community. In addition to affecting survival or behaviour of desiccation‐sensitive species, lower rainfall may indirectly lower abundances of consumers that graze drought‐stressed fungi, with repercussions for higher trophic levels.We tested the hypothesis that trophic structure will differ between the two rainfall scenarios. In particular, we hypothesized that densities of several broadly defined trophic groupings of arthropods would be lower under reduced rainfall.To test this hypothesis, we used sprinklers to impose two rainfall treatments during three growing seasons in roofed, fenced 14‐m2 plots and documented changes in abundance from initial, pre‐treatment densities of 39 arthropod taxa. Experimental plots were subjected to either LOW (fortnightly) or HIGH (weekly) average rainfall based upon climate models and the previous 100 years of regional weekly averages. Unroofed open plots, our reference treatment (REF), experienced higher than average rainfall during the experiment.The two rainfall extremes produced clear negative effects of lowered rainfall on major trophic groups. Broad categories of fungivores, detritivores and predators were more abundant in HIGH than LOW plots by the final year. Springtails (Collembola), which graze fungal hyphae, were 3× more abundant in the HIGH rainfall treatment. Taxa of larger‐bodied fungivores and detritivores, spiders (Araneae), and non‐spider predators were 2× more abundant under HIGH rainfall. Densities of mites (Acari), which include fungivores, detritivores and predators, were 1.5× greater in HIGH rainfall plots. Abundances and community structure of arthropods were similar in REF and experimental plots, showing that effects of rainfall uncovered in the experiment are applicable to nature.This pattern suggests that changes in rainfall will alter bottom‐up control processes in a critical detritus‐based food web of deciduous forests. Our results, in conjunction with other findings on the impact of desiccation on arthropods and fungal growth, suggest that drier conditions will depress densities of fungal consumers, causing declines in higher trophic levels, with possible impacts on soil processes and the larger forest food web. [ABSTRACT FROM AUTHOR]

Objective: To evaluate effectiveness of physical therapy, biofeedback, and/or cognitive behavioral therapy for chronic prostatitis/chronic pelvic pain syndrome (CP and/or CPPS). This symptom complex has resisted resolution from conventional urologic treatment of the prostate, which includes antibiotics, alpha-blockers, and analgesics. Beginning in 1995, a new paradigm was introduced viewing CP and/or CPPS as a psychoneuromuscular disorder driven by protective pelvic floor guarding and psychosocial stress.Methods: A literature search (PubMed, Google Scholar, and the Cochran Library) was conducted from inception through December 2017 using key words related to CP and/or CPPS (eg, prostatitis and pelvic pain) with physical therapy (eg, myofascial trigger point release) and/or biofeedback or cognitive behavioral treatment. Studies were required to include pre- and post-treatment with the National Institutes of Health Chronic Prostatitis Symptom Index (CPSI) scores.Results: Eight studies inclusive of 280 patients met primary inclusion criteria. Study sample sizes ranged from 8 to 116 men (mean = 35); treatment duration ranged from 8 to 26 weeks (mean = 14). Pretreatment mean CPSI scores ranged from 21.7 to 33.5. The nonstandardized weighted mean reduction of CPSI score from baseline was 8.8 points; 95% confidence interval (7.5, 11.1); P <.001. The I2 statistic = 18.5% indicating little heterogeneity between studies. A sensitivity analysis including an additional multimodal intervention study of with 100 patients produced similar findings.Conclusion: Conventional medical treatment often fails to resolve CP and/or CPPS. A 6-point reduction in CPSI score is considered a clinically meaningful improvement of symptoms. This meta-analysis shows that treating CP and/or CPPS as a psychoneuromuscular disorder can significantly exceed this clinical threshold. [ABSTRACT FROM AUTHOR]

Both men and women require treatment for urologic chronic pelvic pain syndromes (UCPPS), which includes interstitial cystitis/painful bladder syndrome, pelvic floor dysfunction, and chronic prostatitis/chronic pelvic pain syndrome. However, it is unknown if men and women respond differently to a protocol that includes specific physical therapy self-treatment using an internal trigger point wand and training in paradoxical relaxation. We performed a retrospective analysis by gender in a single arm, open label, single center clinical trial designed to evaluate the safety and effectiveness of a protocol for the treatment of UCPPS from October, 2008 to May, 2011. 314 adult men (79.9 %) and 79 (20.1 %) women met inclusion criteria. The median duration of symptoms was 60 months. The protocol required an initial 6-day clinic for training followed by a 6-month self-treatment period. The treatment included self-administered pelvic floor trigger point release with an internal trigger point device for physical therapy along with paradoxical relaxation training. Notable gender differences in prior treatments were observed. Men had a lower median [Interquartile Range] NIH-CPSI score at baseline than women (27 [21, 31] vs. 29 [22, 33], p = 0.04). Using a 1-10 scale with 10 = Most Severe, the median reduction in trigger point sensitivity was 3 units for both men and women after 6 months therapy ( p = 0.74). A modified Intention to Treat analysis and a multivariate regression analysis found similar results. We conclude that men and women have similar, significant reductions in trigger point sensitivity with this protocol. [ABSTRACT FROM AUTHOR]

Anemia is a widespread hematological disorder in vertebrates. In channel catfish ( Ictalurus punctatus), anemia is a persistent problem in culture environments, however, its causes and physiological impacts are not well understood. To better understand the symptoms and characterize associated biomarkers of anemia, 1-D H and 2-D H J-resolved NMR were used to analyze metabolite changes in healthy and anemic channel catfish kidney and liver tissue. Additionally, standard physiological analytical techniques were used to analyze blood plasma. NMR analyses revealed energy sources such as glucose were depleted and many metabolites associated with anaerobic metabolism or alternative energy pathways such as lactate, creatine, alanine, acetate and myo-inositol had changed. Energy demanding processes were reduced, such as muscle function, as indicated by reductions in taurine and inosine, and protein synthesis. Stress and oxidative stress related metabolites changed, with increases in valine, leucine and isoleucine and decreases in glutathione. Inhibitory neurotransmitters such as 4-aminobutyric acid (GABA) increased, and excitatory neurotransmitters such as glutamine and glutamate generally decreased, although there were tissue-specific differences. Immune function also decreased in anemic fish. Blood analyses revealed decreased respiratory gas transport capabilities through reductions in erythrocytes and hemoglobin-markers. Taken together, these tissues and analytical techniques produced complementary results, and metabolite expression in anemic channel catfish was similar to that observed in other vertebrates exposed to anoxia, severe hypoxia or experiencing oxidative stress from deficiencies in iron homeostasis. [ABSTRACT FROM AUTHOR]

Scholars contend that correctly applying religious cues is crucial to winning political elections. This article examines the effect of general religious cues by conducting an experiment on a national sample (N = 520). Through the use of a fictitious congressional candidate's webpage, we examine how subtle and overt religious cues interact with citizen religiosity to affect political evaluations. The findings demonstrate that politicians who use overt religious cues run the risk of alienating a large portion of potential voters. Religious cues do, however, appear to become more effective as citizens become more religious. We also find some evidence that overt religious cues are more polarizing than subtle religious cues. This article provides a foundation from which to more thoroughly consider how general religious cues can affect political outcomes and how these cues may interact with other factors. [ABSTRACT FROM AUTHOR]

Citrate is a critical metabolite required to support both mitochondrial bioenergetics and cytosolic macromolecular synthesis. When cells proliferate under normoxic conditions, glucose provides the acetyl-CoA that condenses with oxaloacetate to support citrate production. Tricarboxylic acid (TCA) cycle anaplerosis is maintained primarily by glutamine. Here we report that some hypoxic cells are able to maintain cell proliferation despite a profound reduction in glucose-dependent citrate production. In these hypoxic cells, glutamine becomes a major source of citrate. Glutamine-derived α-ketoglutarate is reductively carboxylated by the NADPH-linked mitochondrial isocitrate dehydrogenase (IDH2) to form isocitrate, which can then be isomerized to citrate. The increased IDH2-dependent carboxylation of glutamine-derived α-ketoglutarate in hypoxia is associated with a concomitant increased synthesis of 2-hydroxyglutarate (2HG) in cells with wild-type IDH1 and IDH2. When either starved of glutamine or rendered IDH2-deficient by RNAi, hypoxic cells are unable to proliferate. The reductive carboxylation of glutamine is part of the metabolic reprogramming associated with hypoxia-inducible factor 1 (HIF1), as constitutive activation of HIF1 recapitulates the preferential reductive metabolism of glutamine-derived α-ketoglutarate even in normoxic conditions. These data support a role for glutamine carboxylation in maintaining citrate synthesis and cell growth under hypoxic conditions. [ABSTRACT FROM AUTHOR]

This study examines the effects of goal framing on opinion about a public health issue. A content analysis of newspaper coverage regarding a New York City trans fat ban identified four frames, each of which invoked a policy goal (promoting public health or protecting business). An experiment tested the effects of goal framing on support for banning trans fat, as well as the effects of competition between frames invoking the same goal and competition between frames invoking different goals. The findings suggest that goal framing can shape opinion about public health issues but that competitive framing can undermine these effects. [ABSTRACT FROM AUTHOR]

The article advances the view that social and economic choices in societies can reasonably adjust as the age structure of the population changes; in particular, some of the bounty of longer lives can reasonably be allocated to prolonging the labor force participation of older workers. Data on reductions in mortality and, in some countries, declines in disability are presented in ways that help to clarify that prolonged working lives may be a natural concomitant of living longer. The article reviews the problems inherent in the combination of living longer and reducing labor force participation at older ages. It discusses two ways to facilitate longer working lives: (1) eliminating penalties on work at older ages—inherent in the provisions of the social security programs in many countries—that induce older persons to leave the labor force at younger ages; and (2) correcting a false rationale—the "boxed economy" view of the labor market—that is often used to support retention of the provisions that induce older persons to leave the labor force. [ABSTRACT FROM AUTHOR]

Most cancers depend on a high rate of aerobic glycolysis for their continued growth and survival. Paradoxically, some cancer cell lines also display addiction to glutamine despite the fact that glutamine is a nonessential amino acid that can be synthesized from glucose. The high rate of glutamine uptake exhibited by glutamine-dependent cells does not appear to result solely from its role as a nitrogen donor in nucleotide and amino acid biosynthesis. Instead, glutamine plays a required role in the uptake of essential amino acids and in maintaining activation of TOR (target of rapamycin) kinase. Moreover, in many cancer cells, glutamine is the primary mitochondrial substrate and is required for maintenance of mitochondrial membrane potential and integrity and for support of the NADPH production needed for redox control and macromolecular synthesis. [ABSTRACT FROM AUTHOR]

This study examines press metacoverage (i.e., news about news) on traditional broadcast network evening news programs, political talk programs on cable television, and political comedy programs. A content analysis found that 2008 presidential primary campaign stories on The O'Reilly Factor, Countdown, and The Daily Show were more likely to cover the news media and to present the news media in a negative light than were stories on NBC Nightly News. The results suggest that people who view political talk and political comedy programs will be exposed to a distinctively unflattering view of the ways in which the press covers elections. Such exposure, in turn, may carry consequences for public opinion. [ABSTRACT FROM AUTHOR]

Recursive algorithms, like quick-sort and recursive data structures, like trees, play a central role in programming. In the context of scientific computing, recursive algorithms and memory layouts are shown here to provide excellent cache and Translation Lookaside Buffer (TLB) locality independently of the platform. We show how, for the first time, generic programming and object-oriented programming allow us to abstract a multitude of dense-matrix memory layouts: from conventional row-major and column-major layouts over Z- and И-Morton orders to block-wise combinations of them. All are provided by a single class that is based on our new matrix abstraction. The algorithmic recursion is supported in generic fashion by classes modelling the new recursator, an analogue of the Standard Template Library iterator. Although this concept supports recursion in general, we focus again on matrix operations. Results are presented for matrix multiplication, on both conventional and tiled representations using both homogeneous and heterogeneous matrix representations. Reaching about 60% peak performance in portable C++ code establishes competitive performance without explicit prefetching and other platform-specific tuning. Comparisons with the manufacturers' libraries show superior locality. These new techniques are embedded in the Matrix Template Library, Version 4 (MTL4). [ABSTRACT FROM AUTHOR]

The article focuses on studies completed by the U.S. National Bureau of Economic Research (NBER) since its formation in September 2003. According to the authors, NBER has conducted studies on Social Security reforms and sustainability. The Bureau has also analyzed changes in the financial resources of retirees in the country, including increases in retirement savings and rising medical spending in the private sector. Effects of changing demographic trends were also analyzed by NBER.

Mammalian cells fuel their growth and proliferation through the catabolism of two main substrates: glucose and glutamine. Most of the remaining metabolites taken up by proliferating cells are not catabolized, but instead are used as building blocks during anabolic macromotecular synthesis. Investigations of phosphoinositol 3-kinase (PI3K) and its downstream effector AKT have confirmed that these oncogenes play a direct role in stimulating glucose uptake and metabolism, rendering the transformed cell addicted to glucose for the maintenance of survival. In contrast, less is known about the regulation of glutamine uptake and metabolism. Here, we report that the transcriptional regulatory properties of the oncogene Myc coordinate the expression of genes necessary for cells to engage in glutamine catabolism that exceeds the cellular requirement for protein and nucleotide biosynthesis. A consequence of this Myc-dependent glutaminolysis is the reprogramming of mitochondrial metabolism to depend on glutamine catabolism to sustain cellular viability and TCA cycle anapleurosis. The ability of Myc-expressing cells to engage in glutaminolysis does not depend on concomitant activation of PI3K or AKT. The stimulation of mitochondrial glutamine metabolism resulted in reduced glucose carbon entering the TCA cycle and a decreased contribution of glucose to the mitochondrial-dependent synthesis of phospholipids. These data suggest that oncogenic levels of Myc induce a transcriptional program that promotes glutaminolysis and triggers cellular addiction to glutamine as a bioenergetic substrate. [ABSTRACT FROM AUTHOR]

Under hypoxic conditions, cells suppress energy-intensive mRNA translation by modulating the mammalian target of rapamycin (mTOR) and pancreatic eIF2α kinase (PERK) pathways. Much is known about hypoxic inhibition of mTOR activity; however, the cellular processes activating PERK remain unclear. Since hypoxia is known to increase intracellular reactive oxygen species (ROS), we hypothesized that hypoxic ROS regulate mTOR and PERK to control mRNA translation and cell survival. Our data indicate that although exogenous ROS inhibit mTOR, eIF2α,and eEF2, mTOR and eEF2 were largely refractory to ROS generated under moderate hypoxia (0.5% O2). In direct contrast, the PERK/eIF2α/ATF4 integrated stress response (ISR) was activated by hypoxic ROS and contributed to global protein synthesis inhibition and adaptive ATF4-mediated gene expression. The ISR as well as exogenous growth factors were critical for cell viability during extended hypoxia, since ISR inhibition decreased the viability of cells deprived of O2 and growth factors. Collectively, our data support an important role for ROS in hypoxic cell survival. Under conditions of moderate hypoxia, ROS induce the ISR, there by promoting energy and redox homeostasis and enhancing cellular survival. [ABSTRACT FROM AUTHOR]

The activity and density of generalist predators, such as carabid beetles, rove beetles and spiders, may increase in response to: (1) increased availability of prey from the belowground subsystem and/or (2) enhanced complexity of aboveground vegetation. Organic farming practices support decomposer populations and enhance habitat complexity due to an increased weed density. A response by generalist predators to such below- or aboveground changes could affect predation rates on herbivores in the aboveground food web. We tested this hypothesis in a replicated field experiment conducted in a winter wheat field, where increased predator activity could lead to improved control of herbivorous pests. In a crossed design, we increased and lowered densities of decomposer prey, and manipulated vegetation complexity using artificial plants in order to examine the effect of structural complexity in isolation from effects of plant-attracted additional prey. Isotomid Collembola exhibited lowest activity-densities (AD) in plots treated with soil insecticide and had gradually increasing AD in untreated plots and plots receiving detrital subsidies. Carabid beetles and cursorial spiders did not respond to increased availability of isotomid prey, and they unexpectedly displayed higher AD in the structurally less-complex plots. Aphid density mirrored the positive response of isotomids to detrital subsidies, suggesting that aphids benefited from reduced predation due to predators switching to abundant prey in the decomposer subsystem. The absence of a numerical response by surface-active predators apparently strengthened this indirect effect of isotomids on aphids. Our results suggest that indirect predator-mediated prey-prey interactions can reduce beneficial effects of detrital subsidies on pest suppression. We further demonstrated that generalist predators may not per se benefit from structural complexity. Both results document the challenges associated with management practices that support generalist predators, as these measures may not necessarily improve herbivore suppression. [ABSTRACT FROM AUTHOR]

Dilated integers form an ordered group of the Cartesian indices into a d-dimensional array represented in the Morton order. Efficient implementations of its operations can be found elsewhere. This paper offers efficient casting (type)conversions to and from an ordinary integer representation. As the Morton order representation for 2D and 3D arrays attracts more users because of its excellent block locality, the efficiency of these conversions becomes important. They are essential for programmers who would use Cartesian indexing there. Two algorithms for each casting conversion are presented here, including to-and-from dilated integers for both d = 2 and d = 3. They fall into two families. One family uses newly compact table lookup, so the cache capacity is better preserved. The other generalizes better to all d, using processor-local arithmetic that is newly presented as abstract d-ary and (d - 1)-ary recurrences. Test results for two and three dimensions generally favor the former. [ABSTRACT FROM AUTHOR]

Interactions among predators that prey on each other and are potential competitors for shared prey (intraguild [IG] predators) are widespread in terrestrial ecosystems and have the potential to strongly influence the dynamics of terrestrial food webs. Ants and spiders are abundant and ubiquitous terrestrial IG predators, yet the strength and consequences of interactions between them are largely unknown. In the leaf-litter food web of a deciduous forest in Kentucky (USA), we tested the direct and indirect effects of ants on spiders and a category of shared prey (Collembola) by experimentally subsidizing ants in open plots in two field experiments. In the first experiment, ant activity was increased, and the density of ants in the litter was doubled, by placing carbohydrate and protein baits in the center of each plot. Gnaphosa spiders were almost twice as abundant and Schizocosa spiders were half as abundant in baited plots relative to controls. There were more tomocerid Collembola in baited plots, suggesting possible indirect effects on Collembola caused by ant-spider interactions. The second experiment, in which screening of two mesh sizes selectively excluded large and small worker ants from a sugar bait, revealed that the large ants, primarily Camponotus, could alone induce similar effects on spiders. Gnaphosa biomass density was almost twice as high in the plots where large ants were more active, whereas Schizocosa biomass density was reduced by half in these plots. Although tomocerid densities did not differ between treatments, tomocerid numbers were negatively correlated with the activity of Formica, another large ant species. Path analysis failed to support the hypothesis that the ant Camponotus indirectly affected tomocerid Collembola through effects on densities of spiders. However, path analysis also revealed other indirect effects of Camponotus affecting tomocerids. These results illustrate the complexity of interactions between and within two major IG predator groups with disparate predatory behaviors, complexities that will have consequences for functioning of the forest-floor food web. [ABSTRACT FROM AUTHOR]

Abstract: Climate-change models predict a more intense hydrological cycle, with both increased and decreased amounts of rainfall in areas covered with temperate deciduous forests. These changes could alter rates of litter decomposition, with consequences for rates of nutrient cycling in the forest ecosystem. To examine impacts of predicted changes in precipitation on the rate of decay of canopy leaves, we placed litterbags in replicated, fenced 14m2 low-rainfall and high-rainfall plots located under individual rainout shelters. Unfenced, open plots served as an ambient treatment. Litter in the high-rainfall and ambient plots decayed 50% and 78% faster, respectively, than litter in the low-rainfall plots. Litter in the ambient plots disappeared 20% faster than in the high-rainfall treatment, perhaps via greater leaching during heavy rainfall events. Ambient rainfall during the experiment was similar in total amount to the high-rainfall treatment, but was more variable in intensity and timing. We used litterbags of different mesh sizes to examine whether changes in rainfall might alter the impacts of major categories of the fauna on litter decay. However, we found no consistent evidence that excluding arthropods of different sizes affected litter decay rate within any of the three rainfall treatments. This research reveals that changes in rainfall predicted to occur with global climate change will likely strongly alter rates of litter decay in deciduous forests. [Copyright &y& Elsevier]

Changes in rainfall predicted to occur with global climate change will likely alter rates of leaf-litter decomposition through direct effects on primary decomposers. In a field experiment replicated at two sites, we show that altered rainfall may also change how cascading trophic interactions initiated by arthropod predators in the leaf litter indirectly influence litter decomposition. On the drier site there was no interaction between rainfall and the indirect effect of predators on decomposition. In contrast, on the moister site spiders accelerated the disappearance rate of deciduous leaf litter under low rainfall, but had no, or possibly a negative, indirect effect under high rainfall. Thus, changes resulting from the more intense hydrological cycle expected to occur with climate change will likely influence how predators indirectly affect an essential ecosystem process. [ABSTRACT FROM AUTHOR]

Cannibalism among generalist predators has implications for the dynamics of terrestrial food webs. Spiders are common, ubiquitous arthropod generalist predators in most natural and managed terrestrial ecosystems. Thus, the relationship of spider cannibalism to food limitation, competition, and population regulation has direct bearing on basic ecological theory and applications such as biological control. This review first briefly treats the different types of spider cannibalism and then focuses in more depth on evidence relating cannibalism to population dynamics and food web interactions to address the following questions: Is cannibalism in spiders a foraging strategy that helps to overcome the effects of a limited supply of calories and/or nutrients? Does cannibalism in spiders reduce competition for prey? Is cannibalism a significant density-dependent factor in spider population dynamics? Does cannibalism dampen spider-initiated trophic cascades? [ABSTRACT FROM AUTHOR]

1. The high number of potential predatory interactions among the many arthropod generalist predators in terrestrial food webs makes exhaustive testing of interaction strengths by field experiments unfeasible. Thus, correlative patterns and laboratory observations of behaviour often form the basis of inferences about the strength of interaction pathways involving generalist predators (intraguild predation). 2. Previous research has revealed a negative correlation between survival of juvenile wolf spiders of the genus Schizocosa (Lycosidae) and densities of another abundant spider family, the Gnaphosidae. 3. Feeding trials in laboratory microcosms with a leaf-litter substrate revealed that gnaphosids prey on juvenile Schizocosa in a structurally complex habitat. 4. Gnaphosid densities were manipulated in two different field experiments, each conducted in a different year, in order to test directly the hypothesis that intraguild predation by gnaphosids limits densities of juvenile Schizocosa. 5. Reducing numbers of gnaphosids, and doubling their numbers to two times the mean natural density, had no impact on the survival of juvenile Schizocosa in either field experiment. This finding suggests that correlative patterns in nature and feeding trials in the laboratory may at times provide deceptively simple and potentially misleading generalisations about the strengths of interaction pathways in complex networks of generalist predators. [ABSTRACT FROM AUTHOR]

In a long-term field experiment, densities of wandering spiders (i.e. species that do not build webs to capture prey) were reduced in order to determine whether or not a major group of microbi-detritivores, the Collembola (springtails), would increase in response to lowered spider predation. Thirty 4-m2 fenced plots (15 spider-removal, 15 control plots) and 15 unfenced, undisturbed reference areas were established in a deciduous forest. Spiders were taken from the removal-treatment after being collected by periodic trapping with pitfall traps that contained no preservative, and by searching the litter surface. Judging from a comparison of the numbers captured during periodic censuses in spider-removal and control plots (one census period was two consecutive days of pitfall trapping), wandering spiders were rapidly reduced by ca. 50% and were maintained at levels lower than control plots for 1.3 years. The reduction in numbers was greatest for wolf spiders (Lycosidae; &ap;90%). Of six families of Collembola abundant in the leaf litter during the experiment, one family, the Tomoceridae, exhibited a significant release from spider predation. Densities of tomocerids, which are the largest and most active springtails on the research site, gradually increased until they were consistently 2× higher in the spider-removal treatment than in either fenced control plots or unfenced, open reference areas. [Copyright &y& Elsevier]

Previous experiments in meadow and forest-floor communities have uncovered a negative indirect effect of spiders and other large epigeic predators on decomposition, presumably through depression of densities of microbi-detritivores. We report the results of a 17-month field experiment in a deciduous forest in which spiders exerted the opposite effect on decomposition. In autumn we collected falling leaves of oak (Quercus), maple (Acer) and hickory (Carya), and placed three bags of mixed litter, and three groups of tethered leaves, in 1-m2 fenced plots. We determined the disappearance rate of these leaves through April of the second year. Spider densities were reduced by >50% in the spider-removal treatment. The rate of leaf-litter disappearance was not higher in spider-removal plots, but instead was ca. 20% lower (P=0.057). Thus, spider predation clearly was not decreasing the rates of litter decomposition in our experiment; on the contrary, the results suggest that spiders were indirectly enhancing decomposition. Possible hypotheses to explain this unexpected result are discussed. [Copyright &y& Elsevier]

Abstract Objective: To determine if emergency personnel, either ambulance or hospital based, can estimate the volume of external blood loss accurately enough to be of potential clinical use in guiding fluid resuscitation. Methods: A total of 61 ambulance and 35 hospital personnel viewed nine scenarios consisting of volumes of blood (100 mL, 400 mL and 700 mL) spilt onto three surfaces — carpet, vinyl and a clothed manikin. They were asked to estimate the blood loss in each case. Results: Estimates of volumes of blood loss on all surfaces were generally inaccurate. Both ambulance and hospital groups were comparable in this regard. Hospital personnel had higher mean estimates than those of ambulance personnel. Of particular clinical relevance were the findings that blood loss on carpet was underestimated and small volumes on a clothed manikin were overestimated. Conclusion: External blood loss estimation by ambulance and hospital personnel is generally too inaccurate to be of clinical use. [ABSTRACT FROM AUTHOR]

Abstract The severity of gill damage (percentage of gill lamellae with lytic lesions) was determined in juveniles from 10 USDA 103 line channel catfish Ictalurus punctatus full-sib families, 10 channel catfish×blue catfish I. furcatus backcross hybrid (7/8 channel catfish, 1/8 blue catfish) full-sib families and a mixed-family group of blue catfish placed in a commercial catfish pond experiencing proliferative gill disease (PGD)-related fish mortalities. An initial challenge was conducted with all families, and a second challenge was conducted using the two most susceptible (most gill damage) channel catfish and backcross hybrid families and the two most resistant (least gill damage) channel catfish and backcross hybrid families. In the initial challenge, percentage gill damage was not different between channel catfish (12.3%) and backcross hybrids (11.6%), but was lower in blue catfish (0.2%). Mean percentage gill damage in the second challenge was not different among resistant backcross hybrid families (6.9%), resistant channel catfish families (7.6%) and blue catfish (4.8%), but was higher in susceptible backcross hybrid and channel catfish families (19.0% and 11.9% respectively). The correlation among family means for gill damage from challenge 1 and challenge 2 was r =0.87. Consistent differences between channel catfish and blue catfish and between resistant and susceptible families within genetic groups for gill damage after PGD challenge suggest that there is a genetic component for resistance to PGD and that improving PGD resistance through selection may be possible. [ABSTRACT FROM AUTHOR]

Theory predicts that allochthonous energy subsidies can modify the strength of trophic cascades in food webs. We tested the hypothesis that a detrital subsidy would enhance trophic cascades in the grazing food web of an agroecosystem in which generalist predators, wolf spiders and carabid beetles, feed both on detritivores and herbivores. We crossed detritus-addition with predator-removal treatments in replicated 8 × 8 m open and fenced plots of cucumbers and squash. Collembola, a major detritivore, became 2-4 times more abundant in detritus-addition than control plots; densities of other detritivores also increased. Although the detrital subsidy initially increased ground beetle numbers and produced a 2-3-fold increase in wolf spider densities, we found no consistent evidence of strong trophic cascades measured as changes in fruit yield in either detritus-addition or predator-removal treatments. This result contrasts with predator-removal experiments in previous years in the same study area, which revealed strong cascades affecting cucumber yield. We hypothesize that (1) competition between cucurbits and fungi for nitrogen in the detritus-addition plots, (2) unusually high herbivore densities in the spring cucumber crop, and low densities on the summer squash crop, (3) changes in patterns of intraguild predation in the detritus-addition plots, and (4) perhaps a switch by generalist predators to prey of the detrital food web all may have contributed to preventing the detrital subsidy from benefiting primary producers via an enhanced trophic cascade. [ABSTRACT FROM AUTHOR]

Abstract 1 Spiders and carabid beetles are abundant generalist predators that prey upon insect pests of soybean. A field experiment was conducted to determine the impact of spiders and carabids on soybean yield. Prior to planting, three 7 × 7 m plots were fenced in order to reduce spider and carabid immigration. Carabids that emerged within the plots were not removed, but spiders that ballooned into these predator-reduction plots or that entered by climbing the fence were removed by pitfall trapping and searching the vegetation. Three unmanipulated, unfenced plots served as the control treatment. 2 Densities of spiders on soybean vegetation, and activity-densities of spiders and carabids determined by pitfall trapping, were c . 75% lower in the spider-carabid reduction treatment than in control plots. Despite clear differences between treatments in numbers and activity of these major generalist predators, the weight of soybeans harvested did not differ between control and spider-carabid reduction plots. 3 Paralleling the absence of an effect of predator reduction on soybean yield was the absence of any significant difference between treatments in densities of whiteflies (Aleyrodidae), leafhoppers (Cicadellidae), thrips (Thysanoptera), Lepidoptera larvae and herbivorous Coleoptera. 4 Our experiment provides no evidence that spiders and carabid beetles at ambient densities affect soybean yield. Low populations of pest species or low predation pressure on soybean pests by spiders and carabids at the ambient densities of this experiment could be responsible for this result. [ABSTRACT FROM AUTHOR]

Examines trophic cascades generated by a community of generalist predators. Effect of intraguild predation on the ability of two taxa of generalist predators, carabid beetles and lycosid spiders to control herbivore densities in gardens of cucumber and squash; Impact of predators on herbivore densities; Indirect effect on fruit production.

Deals with a study which evaluated the overall magnitude of trophic cascades in terrestrial arthropod-dominated food webs and conditions affecting their occurrence and strength. Background of the theory of trophic cascades; Data and methodology used; Results and discussion.

Focuses on survival regression analysis (SRA) in studying the effect of asymmetry on contest duration for encounters between Mediterranean female tarantulas. Advantages of using SRA; Provision of unbiased parameter estimates; Details on the analysis of hazard functions.

With the emergence of diseases, the U.S. catfish industry is under challenge. Current trends prefer autochthonous bacteria as potential probiotic candidates owing to their adaptability and capacity to effectively colonize the host's intestine, which can enhance production performance and bolster disease resistance. The objective of this study was to isolate an autochthonous bacterium as probiotic for hybrid catfish. Initially, an analysis of the intestinal microbiota of hybrid catfish reared in earthen ponds was conducted for subsequent probiotic development. Twenty lactic acid bacteria were isolated from the digesta of overperforming catfish, and most of the candidates demonstrated probiotic traits, including proteolytic and lipolytic abilities; antagonistic inhibition of catfish enteric bacterial pathogens, negative haemolytic activity and antibiotic susceptibility. Subsequent to this screening process, an isolate of Lactococcus lactis (MA5) was deemed the most promising probiotic candidate. In silico analyses were conducted, and several potential probiotic functions were predicted, including essential amino acids and vitamin synthesis. Moreover, genes for three bacteriocins, lactococcin A, enterolysin A and sactipeptide BmbF, were identified. Lastly, various protectant media for lyophilization of MA5 were assessed. These findings suggest that Lactococcus lactis MA5 can be an autochthonous probiotic from hybrid catfish, holding promise to be further tested in feeding trials. [ABSTRACT FROM AUTHOR]

Examines the bottom-up limitation of predaceous arthropods in a detritus-based terrestrial food web. Effects of an increase in the resource base of a food web; Food-web structure and dynamics; Detrital food web; Detritivores; Fungivores; Terrestrial arthropod community.

This article discusses retirement trends in the United States and the role of social security and employer-provided pension plans in inducing early retirement. In spite of the rapid aging of the population and the increase in life expectancy, the labor force participation of older people in the United States has decreased dramatically over the past three or four decades. The accelerated decrease in labor force participation corresponds roughly to the introduction of social security and the adaptation of employer-provided pension plans. This article illustrates that the social security and employer-provided pension plans provide substantial incentive to leave the labor force early. The quantitative effect of this inducement is illustrated by simulating the effects of changes in pension plan and social security provisions on the retirement decisions of employees in a large firm, who are covered by a typically defined benefit plan. Health status is also an important determinant of retirement and the effect of health status may interact with the effect of pension plan provisions. Available data also suggest that employer-provided retiree health insurance may facilitate early retirement and the insurance effect may, in turn, interact with health status and with pension plan provisions.

Examines the relative contributions of mortality from natural enemies and cannibalism to the regulation of the wolf spider population. Measurement of the rates of cannibalism; contribution of natural enemies to spider mortality; Description of cannibalism.