275 research outputs found

    Webs in Vitro and in Vivo: Spiders Alter their Orb-Web Spinning Behavior in the Laboratory

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    Many studies of the elegant architectures of orb webs are conducted in controlled laboratory environments that remove environmental variability. The degree to which spider behavior in these circumstances resembles that of spiders in the wild is largely unknown. We compared web architecture and silk investment of furrowed orb weavers Larinioides corium\u27s (Clerck 1757) building webs in laboratory cages and spinning webs on fences in the field and found significant differences. The volume of major ampullate silk in radii was 53% lower in cage webs, primarily because the silk was 50% thinner, but also because spiders tended to spin 14% fewer radii than in fence webs. Cage spiders also invested about 40% less flagelliform silk and aggregate glue in the capture spiral, although the difference was not statistically significant, a trend primarily driven by a decrease in the length of the glue-coated capture spiral. These patterns were consistent with spiders reducing silk investment when building at new web sites while they assessed insect abundance. Differences in the type of substrate for web attachment, amount of available space, and condition may also have influenced web architecture. Cage webs were more symmetrical than fence webs, which displayed an unusual horizontal asymmetry that may have maximized their capture areas within the constraints of the available fence-railing attachment sites. Our findings suggest using caution when generalizing the properties of laboratory-spun webs to more natural conditions. More importantly, they demonstrate that orb spiders actively modify their behaviors when spinning webs under different conditions

    Integrating Financial Therapy within Family-Owned Businesses: A Theoretical Case Vignette with Recommended Strategies for Consulting with Copreneurs

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    Broadly speaking, finances are often one of the most strenuous aspects of a relationship. One potential contributing factor to financial conflict experienced by couples are having different beliefs or attitudes towards money, coined previously as money scripts (Klontz, Kahler, & Klontz, 2008). Differing money scripts between partners can cause a breach in understanding of their partner\u27s internal experience around money that may lead to misunderstanding and conflict. This may be magnified for copreneurs, or romantic partners, who integrate a personal and working relationship within a business’s ownership structure. In this unique arrangement of personal and professional relationships, the traditional lines separating work and home life are either nonexistent or blurred. This paper serves to explore the conflict through a hypothetical case study and provides detailed financial therapy interventions that may be used to help copreneurs who are experiencing money conflict. The outline of interventions serves to aid financial therapists in their work with clients who are part of a family-owned business by helping these clients better communicate through the unique dynamics of a copreneur relationship

    Clinical Science Unique risks for mortality in patients with end-stage renal disease undergoing nonemergent colorectal surgery

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    Abstract BACKGROUND: The aim of this study was to identify unique risk factors for mortality in patients with end-stage renal disease undergoing nonemergent colorectal surgery. METHODS: A multivariate logistic regression model predicting 30-day mortality was constructed for patients with end-stage renal disease undergoing nonemergent colorectal procedures. Data were obtained from the National Surgical Quality Improvement Program (2005Program ( -2010. RESULTS: Among the 394 patients analyzed, those with serum creatinine levels .7.5 mg/dL had .07 times the adjusted mortality risk of those with levels ,3.5 mg/dL. For colorectal surgery patients, the average serum creatinine level was 5.52 6 2.6 mg/dL, and mortality was 13% (n 5 50). CONCLUSIONS: High serum creatinine was associated with a lower risk for mortality in patients with end-stage renal disease, even though creatinine is often considered a risk factor for surgery. These results show how variables from a patient-centered subpopulation can differ in meaning from the general population. 4 This database is a tool that records perioperative risk factors for addressing surgical morbidity and mortality. Our objective was to use the NSQIP data to create a multivariate model to identify unique risk factors predicting mortality in patients with ESRD undergoing nonemergent colorectal procedures

    Bioprospecting Finds the Toughest Biological Material: Extraordinary Silk from a Giant Riverine Orb Spider

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    Background Combining high strength and elasticity, spider silks are exceptionally tough, i.e., able to absorb massive kinetic energy before breaking. Spider silk is therefore a model polymer for development of high performance biomimetic fibers. There are over 41.000 described species of spiders, most spinning multiple types of silk. Thus we have available some 200.000+ unique silks that may cover an amazing breadth of material properties. To date, however, silks from only a few tens of species have been characterized, most chosen haphazardly as model organisms (Nephila) or simply from researchers' backyards. Are we limited to ‘blindly fishing’ in efforts to discover extraordinary silks? Or, could scientists use ecology to predict which species are likely to spin silks exhibiting exceptional performance properties? Methodology We examined the biomechanical properties of silk produced by the remarkable Malagasy ‘Darwin's bark spider’ (Caerostris darwini), which we predicted would produce exceptional silk based upon its amazing web. The spider constructs its giant orb web (up to 2.8 m2) suspended above streams, rivers, and lakes. It attaches the web to substrates on each riverbank by anchor threads as long as 25 meters. Dragline silk from both Caerostris webs and forcibly pulled silk, exhibits an extraordinary combination of high tensile strength and elasticity previously unknown for spider silk. The toughness of forcibly silked fibers averages 350 MJ/m3, with some samples reaching 520 MJ/m3. Thus, C. darwini silk is more than twice tougher than any previously described silk, and over 10 times better than Kevlar®. Caerostris capture spiral silk is similarly exceptionally tough. Conclusions Caerostris darwini produces the toughest known biomaterial. We hypothesize that this extraordinary toughness coevolved with the unusual ecology and web architecture of these spiders, decreasing the likelihood of bridgelines breaking and collapsing the web into the river. This hypothesis predicts that rapid change in material properties of silk co-occurred with ecological shifts within the genus, and can thus be tested by combining material science, behavioral observations, and phylogenetics. Our findings highlight the potential benefits of natural history–informed bioprospecting to discover silks, as well as other materials, with novel and exceptional properties to serve as models in biomimicry.Primary funding for this work came from the Slovenian Research Agency (grant Z1-9799-0618-07 to I. Agnarsson), the National Geographic Society (grant 8655-09 to the authors), and the National Science Foundation (grants DBI-0521261, DEB-0516038 and IOS-0745379 to T. Blackledge). Additional funding came from the European Community 6th Framework Programme (a Marie Curie International Reintegration Grant MIRG-CT-2005 036536 to M. Kuntner). The 2001 field work was supported by the Sallee Charitable Trust grant to I. Agnarsson and M. Kuntner and by a United States National Science Foundation grant (DEB-9712353) to G. Hormiga and J. A. Coddington. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewe

    How Did the Spider Cross the River? Behavioral Adaptations for River-Bridging Webs in Caerostris darwini (Araneae: Araneidae)

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    Interspecific coevolution is well described, but we know significantly less about how multiple traits coevolve within a species, particularly between behavioral traits and biomechanical properties of animals' "extended phenotypes". In orb weaving spiders, coevolution of spider behavior with ecological and physical traits of their webs is expected. Darwin's bark spider (Caerostris darwini) bridges large water bodies, building the largest known orb webs utilizing the toughest known silk. Here, we examine C. darwini web building behaviors to establish how bridge lines are formed over water. We also test the prediction that this spider's unique web ecology and architecture coevolved with new web building behaviors.We observed C. darwini in its natural habitat and filmed web building. We observed 90 web building events, and compared web building behaviors to other species of orb web spiders.Caerostris darwini uses a unique set of behaviors, some unknown in other spiders, to construct its enormous webs. First, the spiders release unusually large amounts of bridging silk into the air, which is then carried downwind, across the water body, establishing bridge lines. Second, the spiders perform almost no web site exploration. Third, they construct the orb capture area below the initial bridge line. In contrast to all known orb-weavers, the web hub is therefore not part of the initial bridge line but is instead built de novo. Fourth, the orb contains two types of radial threads, with those in the upper half of the web doubled. These unique behaviors result in a giant, yet rather simplified web. Our results continue to build evidence for the coevolution of behavioral (web building), ecological (web microhabitat) and biomaterial (silk biomechanics) traits that combined allow C. darwini to occupy a unique niche among spiders

    Embryology and bony malformations of the craniovertebral junction

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    BACKGROUND: The embryology of the bony craniovertebral junction (CVJ) is reviewed with the purpose of explaining the genesis and unusual configurations of the numerous congenital malformations in this region. Functionally, the bony CVJ can be divided into a central pillar consisting of the basiocciput and dental pivot and a two-tiered ring revolving round the central pivot, comprising the foramen magnum rim and occipital condyles above and the atlantal ring below. Embryologically, the central pillar and the surrounding rings descend from different primordia, and accordingly, developmental anomalies at the CVJ can also be segregated into those affecting the central pillar and those affecting the surrounding rings, respectively. DISCUSSION: A logical classification of this seemingly unwieldy group of malformations is thus possible based on their ontogenetic lineage, morbid anatomy, and clinical relevance. Representative examples of the main constituents of this classification scheme are given, and their surgical treatments are selectively discussed

    Disinfection of Ocular Cells and Tissues by Atmospheric-Pressure Cold Plasma

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    Background: Low temperature plasmas have been proposed in medicine as agents for tissue disinfection and have received increasing attention due to the frequency of bacterial resistance to antibiotics. This study explored whether atmospheric-pressure cold plasma (APCP) generated by a new portable device that ionizes a flow of helium gas can inactivate ocular pathogens without causing significant tissue damage. Methodology and Principal Findings: We tested the APCP effects on cultured Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Candida albicans, Aspergillus fumigatus and Herpes simplex virus-1, ocular cells (conjunctival fibroblasts and keratocytes) and ex-vivo corneas. Exposure to APCP for 0.5 to 5 minutes significantly reduced microbial viability (colony-forming units) but not human cell viability (MTT assay, FACS and Tunel analysis) or the number of HSV-1 plaque-forming units. Increased levels of intracellular reactive oxygen species (ROS) in exposed microorganisms and cells were found using a FACS-activated 2',7'-dichlorofluorescein diacetate probe. Immunoassays demonstrated no induction of thymine dimers in cell cultures and corneal tissues. A transient increased expression of 8-OHdG, genes and proteins related to oxidative stress (OGG1, GPX, NFE2L2) was determined in ocular cells and corneas by HPLC, qRT-PCR and Western blot analysis. Conclusions: A short application of APCP appears to be an efficient and rapid ocular disinfectant for bacteria and fungi without significant damage on ocular cells and tissues, although the treatment of conjunctival fibroblasts and keratocytes caused a time-restricted generation of intracellular ROS and oxidative stress-related responses

    Low exposure long-baseline neutrino oscillation sensitivity of the DUNE experiment

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    The Deep Underground Neutrino Experiment (DUNE) will produce world-leading neutrino oscillation measurements over the lifetime of the experiment. In this work, we explore DUNE's sensitivity to observe charge-parity violation (CPV) in the neutrino sector, and to resolve the mass ordering, for exposures of up to 100 kiloton-megawatt-years (kt-MW-yr). The analysis includes detailed uncertainties on the flux prediction, the neutrino interaction model, and detector effects. We demonstrate that DUNE will be able to unambiguously resolve the neutrino mass ordering at a 3σ\sigma (5σ\sigma) level, with a 66 (100) kt-MW-yr far detector exposure, and has the ability to make strong statements at significantly shorter exposures depending on the true value of other oscillation parameters. We also show that DUNE has the potential to make a robust measurement of CPV at a 3σ\sigma level with a 100 kt-MW-yr exposure for the maximally CP-violating values \delta_{\rm CP}} = \pm\pi/2. Additionally, the dependence of DUNE's sensitivity on the exposure taken in neutrino-enhanced and antineutrino-enhanced running is discussed. An equal fraction of exposure taken in each beam mode is found to be close to optimal when considered over the entire space of interest
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