423 research outputs found

    Long-term increase in mesozooplankton biomass in the Sargasso Sea: Linkage to climate and implications for food web dynamics and biogeochemical cycling

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    Changes in zooplankton biomass and species composition over long time scales can have significant effects on biogeochemical cycling and transfer of energy to higher trophic levels. We analyzed size-fractionated mesozooplankton biomass (\u3e200 mu m) from biweekly to monthly day and night tows taken from 1994 to 2010 in the epipelagic zone at the Bermuda Atlantic Time series Study (BATS) site in the oligotrophic North Atlantic subtropical gyre. During this 17-year period total mesozooplankton biomass increased 61% overall, although a few short-term downturns occurred over the course of the time series. The overall increase was higher in the nighttime compared to daytime, resulting in an increase in calculated diel vertical migrator biomass. The largest seasonal increase in total biomass was in the late-winter to spring (February-April). Associated with the larger increase in late-winter/spring biomass was a shift in the timing of annual peak biomass during the latter half of the time series (from March/April to a distinct March peak for all size fractions combined, and April to March for the 2-5 mm size fractions). Zooplankton biomass was positively correlated with sea-surface temperature, water column stratification, and primary production, and negatively correlated with mean temperature between 300 and 600 m. Significant correlations exist between multidecadal climate indices-the North Atlantic Oscillation plus three different Pacific Ocean climate indices, and BATS zooplankton biomass, indicating connections between patterns in climate forcing and ecosystem response. Resultant changes in biogeochemical cycling include an increase in the magnitude of both active carbon flux by diel vertical migration and passive carbon flux of fecal pellets as components of the export flux. The most likely mechanism driving the zooplankton biomass increase is bottom-up control by smaller phytoplankton, which has also increased in biomass and production at BATS, translating up the microbial food web into mesozooplankton. Decreases in top-down control or expansion of the range of tropical species northward as a result of warming may also play a role

    Regulation of immunity during visceral Leishmania infection

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    Unicellular eukaryotes of the genus Leishmania are collectively responsible for a heterogeneous group of diseases known as leishmaniasis. The visceral form of leishmaniasis, caused by L. donovani or L. infantum, is a devastating condition, claiming 20,000 to 40,000 lives annually, with particular incidence in some of the poorest regions of the world. Immunity to Leishmania depends on the development of protective type I immune responses capable of activating infected phagocytes to kill intracellular amastigotes. However, despite the induction of protective responses, disease progresses due to a multitude of factors that impede an optimal response. These include the action of suppressive cytokines, exhaustion of specific T cells, loss of lymphoid tissue architecture and a defective humoral response. We will review how these responses are orchestrated during the course of infection, including both early and chronic stages, focusing on the spleen and the liver, which are the main target organs of visceral Leishmania in the host. A comprehensive understanding of the immune events that occur during visceral Leishmania infection is crucial for the implementation of immunotherapeutic approaches that complement the current anti-Leishmania chemotherapy and the development of effective vaccines to prevent disease.The research leading to these results has received funding from the European Community’s Seventh Framework Programme under grant agreement No.602773 (Project KINDRED). VR is supported by a post-doctoral fellowship granted by the KINDReD consortium. RS thanks the Foundation for Science and Technology (FCT) for an Investigator Grant (IF/00021/2014). This work was supported by grants to JE from ANR (LEISH-APO, France), Partenariat Hubert Curien (PHC) (program Volubilis, MA/11/262). JE acknowledges the support of the Canada Research Chair Program

    Comprehensive and Integrated Genomic Characterization of Adult Soft Tissue Sarcomas

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    Summary Sarcomas are a broad family of mesenchymal malignancies exhibiting remarkable histologic diversity. We describe the multi-platform molecular landscape of 206 adult soft tissue sarcomas representing 6 major types. Along with novel insights into the biology of individual sarcoma types, we report three overarching findings: (1) unlike most epithelial malignancies, these sarcomas (excepting synovial sarcoma) are characterized predominantly by copy-number changes, with low mutational loads and only a few genes (TP53, ATRX, RB1) highly recurrently mutated across sarcoma types; (2) within sarcoma types, genomic and regulomic diversity of driver pathways defines molecular subtypes associated with patient outcome; and (3) the immune microenvironment, inferred from DNA methylation and mRNA profiles, associates with outcome and may inform clinical trials of immune checkpoint inhibitors. Overall, this large-scale analysis reveals previously unappreciated sarcoma-type-specific changes in copy number, methylation, RNA, and protein, providing insights into refining sarcoma therapy and relationships to other cancer types

    A portable near infrared spectroscopy system for bedside monitoring of newborn brain

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    BACKGROUND: Newborns with critical health conditions are monitored in neonatal intensive care units (NICU). In NICU, one of the most important problems that they face is the risk of brain injury. There is a need for continuous monitoring of newborn's brain function to prevent any potential brain injury. This type of monitoring should not interfere with intensive care of the newborn. Therefore, it should be non-invasive and portable. METHODS: In this paper, a low-cost, battery operated, dual wavelength, continuous wave near infrared spectroscopy system for continuous bedside hemodynamic monitoring of neonatal brain is presented. The system has been designed to optimize SNR by optimizing the wavelength-multiplexing parameters with special emphasis on safety issues concerning burn injuries. SNR improvement by utilizing the entire dynamic range has been satisfied with modifications in analog circuitry. RESULTS AND CONCLUSION: As a result, a shot-limited SNR of 67 dB has been achieved for 10 Hz temporal resolution. The system can operate more than 30 hours without recharging when an off-the-shelf 1850 mAh-7.2 V battery is used. Laboratory tests with optical phantoms and preliminary data recorded in NICU demonstrate the potential of the system as a reliable clinical tool to be employed in the bedside regional monitoring of newborn brain metabolism under intensive care

    Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.

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    Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14·2 per cent (646 of 4544) and the 30-day mortality rate was 1·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7·61, 95 per cent c.i. 4·49 to 12·90; P < 0·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability

    Avoidable mortality attributable to anthropogenic fine particulate matter (Pm2.5) in Australia

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    Ambient fine particulate matter 2.5) air pollution increases premature mortalityglobally. Some PM2.5 is natural, but anthropogenic PM2.5 is comparatively avoidable. We determinedthe impact of long-term exposures to the anthropogenic PM component on mortality in Australia.PM2.5-attributable deaths were calculated for all Australian Statistical Area 2 (SA2; n = 2310) regions.All-cause death rates from Australian mortality and population databases were combined withannual anthropogenic PM2.5 exposures for the years 2006–2016. Relative risk estimates were derivedfrom the literature. Population-weighted average PM2.5 concentrations were estimated in eachSA2 using a satellite and land use regression model for Australia. PM2.5-attributable mortality wascalculated using a health-impact assessment methodology with life tables and all-cause death rates.The changes in life expectancy (LE) from birth, years of life lost (YLL), and economic cost of lostlife years were calculated using the 2019 value of a statistical life. Nationally, long-term populationweighted average total and anthropogenic PM2.5 concentrations were 6.5 µg/m3(min 1.2–max 14.2)and 3.2 µg/m3(min 0–max 9.5), respectively. Annually, anthropogenic PM2.5-pollution is associatedwith 2616 (95% confidence intervals 1712, 3455) deaths, corresponding to a 0.2-year (95% CI 0.14, 0.28)reduction in LE for children aged 0–4 years, 38,962 (95%CI 25,391, 51,669) YLL and an average annualeconomic burden of 6.2billion(956.2 billion (95%CI 4.0 billion, $8.1 billion). We conclude that the anthropogenicPM2.5-related costs of mortality in Australia are higher than community standards should allow,and reductions in emissions are recommended to achieve avoidable mortality

    Gradual phyletic evolution at the generic level in early Eocene omomyid primates

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    Analysis of dental morphology in over 600 stratigraphically controlled specimens of tarsier-like primates from early Eocene strata in Bighorn Basin, Wyoming, provides important new data for understanding the tempo and mode of evolution in primates

    Patients with persistent medically unexplained symptoms in general practice: characteristics and quality of care

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    <p>Abstract</p> <p>Background</p> <p>Medically unexplained physical symptoms (MUPS) are common in general practice (GP), and are even more problematic as they become persistent. The present study examines the relationship between persistent MUPS in general practice on the one hand and quality of life, social conditions, and coping on the other hand. Additionally, it is examined how patients with persistent MUPS evaluate the quality of GP-care.</p> <p>Methods</p> <p>Data were used from a representative survey of morbidity in Dutch general practice, in which data from the electronic medical records were extracted. A random sample of patients participated in an extensive health interview and completed self-reported measures on social isolation, coping and the quality of GP-care. Patients with persistent MUPS (N = 192) were compared with general practice patients not meeting the criteria for persistent MUPS (N = 7.314), and with a group of patients that visited the GP in comparable rates for medical diagnoses (N = 2.265). Multiple logistic regression analyses were used to control for relevant socio-demographic variables and chronic diseases.</p> <p>Results</p> <p>After adjustment for demographics and chronic diseases, patients with persistent MUPS reported more psychological distress, more functional impairment, more social isolation, and they evaluated the quality of GP-care less positive than the other two patient groups. Although the majority of MUPS patients were positive about the quality of GP-care, they more often felt that they were not taken seriously or not involved in treatment decisions, and more often reported that the GP did not take sufficient time. The three groups did not differ with respect to the statement that the GP unnecessarily explains physical problems as psychological ones.</p> <p>Conclusion</p> <p>Strengthening MUPS patients' social network and encouraging social activities may be a meaningful intervention in which the GP may play a stimulating role. To further improve MUPS patients' satisfaction with GP-care, GPs may pay extra attention to taking sufficient time when treating MUPS patients, taking the problems seriously, and involving them in treatment decisions.</p

    A Nomenclature for Vertebral Fossae in Sauropods and Other Saurischian Dinosaurs

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    The axial skeleton of extinct saurischian dinosaurs (i.e., theropods, sauropodomorphs), like living birds, was pneumatized by epithelial outpocketings of the respiratory system. Pneumatic signatures in the vertebral column of fossil saurischians include complex branching chambers within the bone (internal pneumaticity) and large chambers visible externally that are bounded by neural arch laminae (external pneumaticity). Although general aspects of internal pneumaticity are synapomorphic for saurischian subgroups, the individual internal pneumatic spaces cannot be homologized across species or even along the vertebral column, due to their variability and absence of topographical landmarks. External pneumatic structures, in contrast, are defined by ready topological landmarks (vertebral laminae), but no consistent nomenclatural system exists. This deficiency has fostered confusion and limited their use as character data in phylogenetic analysis.We present a simple system for naming external neural arch fossae that parallels the one developed for the vertebral laminae that bound them. The nomenclatural system identifies fossae by pointing to reference landmarks (e.g., neural spine, centrum, costal articulations, zygapophyses). We standardize the naming process by creating tripartite names from “primary landmarks,” which form the zygodiapophyseal table, “secondary landmarks,” which orient with respect to that table, and “tertiary landmarks,” which further delineate a given fossa.The proposed nomenclatural system for lamina-bounded fossae adds clarity to descriptions of complex vertebrae and allows these structures to be sourced as character data for phylogenetic analyses. These anatomical terms denote potentially homologous pneumatic structures within Saurischia, but they could be applied to any vertebrate with vertebral laminae that enclose spaces, regardless of their developmental origin or phylogenetic distribution

    Behavioural and neuroanatomical correlates of auditory speech analysis in primary progressive aphasias

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    Background Non-verbal auditory impairment is increasingly recognised in the primary progressive aphasias (PPAs) but its relationship to speech processing and brain substrates has not been defined. Here we addressed these issues in patients representing the non-fluent variant (nfvPPA) and semantic variant (svPPA) syndromes of PPA. Methods We studied 19 patients with PPA in relation to 19 healthy older individuals. We manipulated three key auditory parameters—temporal regularity, phonemic spectral structure and prosodic predictability (an index of fundamental information content, or entropy)—in sequences of spoken syllables. The ability of participants to process these parameters was assessed using two-alternative, forced-choice tasks and neuroanatomical associations of task performance were assessed using voxel-based morphometry of patients’ brain magnetic resonance images. Results Relative to healthy controls, both the nfvPPA and svPPA groups had impaired processing of phonemic spectral structure and signal predictability while the nfvPPA group additionally had impaired processing of temporal regularity in speech signals. Task performance correlated with standard disease severity and neurolinguistic measures. Across the patient cohort, performance on the temporal regularity task was associated with grey matter in the left supplementary motor area and right caudate, performance on the phoneme processing task was associated with grey matter in the left supramarginal gyrus, and performance on the prosodic predictability task was associated with grey matter in the right putamen. Conclusions Our findings suggest that PPA syndromes may be underpinned by more generic deficits of auditory signal analysis, with a distributed cortico-subcortical neuraoanatomical substrate extending beyond the canonical language network. This has implications for syndrome classification and biomarker development
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