8,172 research outputs found
Development of catecholamine and cortisol stress responses in zebrafish.
Both adrenal catecholamines and steroids are known to be involved in the stress response, immune function, blood pressure and energy homeostasis. The response to stress is characterized by the activation of the hypothalamus-pituitary-adrenal (HPA) axis and the sympathetic-adrenomedullary system, though the correlation with activation and development is not well understood. We evaluated the stress response of both cortisol and catecholamines during development in zebrafish. Zebrafish at two different stages of development were stressed in one of two different ways and cortisol and catecholamine were measured. Cortisol was measured by enzyme immune assay and catecholamine was measured by ELISA. Our results show that stress responses are delayed until after the synthesis of both cortisol and catecholamines. These observations suggest that the development of HPA axis may be required for the acquisition of the stress response for cortisol and catecholamines
An evaluation of the use of a computer game in improving the choice reaction time of adults with intellectual disabilities
People with intellectual disabilities have difficulty making decisions and this may hinder their independence and inclusion in society. Interactive computer software may give them the opportunity to practice the underlying components of this skill. This study aimed to discover if repeated sessions playing a computer game involving aspects of decision making, such as collecting relevant information and controlling impulsivity, would improve performance in two non-computer based tests of decision making. 12 adults with intellectual disabilities were randomly assigned to either an intervention group or control group. They were all exposed to 10 twice weekly sessions, playing either the intervention game or the control game, which involved simple reaction time only. After repeated sessions, the intervention group showed a significant improvement in game score, with researcher assistance significantly decreasing. At follow up, the intervention group showed a significant decrease from baseline in the number of guesses made before guessing correctly on both of the decision making tests. The decrease observed in the control group failed to reach significance
Fire effects on aquatic ecosystems: an assessment of the current state of science
Fire is a prevalent feature of many landscapes and has numerous and complex effects on geological, hydrological, ecological, and economic systems. In some regions, the frequency and intensity of wildfire have increased in recent years and are projected to escalate with predicted climatic and landuse changes. In addition, prescribed burns continue to be used in many parts of the world to clear vegetation for development projects, encourage desired vegetation, and reduce fuel loads. Given the prevalence of fire on the landscape, authors of papers in this special series examine the complexities of fire as a disturbance shaping freshwater ecosystems and highlight the state of the science. These papers cover key aspects of fire effects that range from vegetation loss and recovery in watersheds to effects on hydrology and water quality with consequences for communities (from algae to fish), food webs, and ecosystem processes (e.g., organic matter subsidies, nutrient cycling) across a range of scales. The results presented in this special series of articles expand our knowledge of fire effects in different biomes, water bodies, and geographic regions, encompassing aquatic population, community, and ecosystem responses. In this overview, we summarize each paper and emphasize its contributions to knowledge on fire ecology and freshwater ecosystems. This overview concludes with a list of 7 research foci that are needed to further our knowledge of fire effects on aquatic ecosystems, including research on: 1) additional biomes and geographic regions; 2) additional habitats, including wetlands and lacustrine ecosystems; 3) different fire severities, sizes, and spatial configurations; and 4) additional response variables (e.g., ecosystem processes) 5) over long (>5 y) time scales 6) with more rigorous study designs and data analyses, and 7) consideration of the effects of fire management practices and policies on aquatic ecosystems
Development of digital PCR DNA methylation assays for blood plasma-based diagnosis of lung cancer
Lung cancer is the leading cause of cancer-related death and is usually diagnosed at advanced stage leading to poor patient survival. Therefore there is a pressing need for early detection of disease. DNA methylation is an early event in carcinogenesis and a limited number of diagnostic markers have been developed for clinical use. This thesis seeks to address whether the development and application of novel DNA methylation assays can diagnose lung cancer at early stage. Previously identified DNA methylation biomarkers, along with novel targets identified by methylation microarray, were developed in multiplex assay format. Twelve markers were used to screen 417 bronchoalveolar lavage specimens from Liverpool Lung Project (LLP) subjects divided into training and validation sets. The optimal biomarker panel (CDKN2A, RARB and TERT) demonstrated improved clinical sensitivity and specificity (Sensitivity/Specificity: 85.7%/93.8%, AUC: 0.91) compared to previous studies. The optimal methylation algorithm detected more than 60% of stage T1 tumours and 93 cytologically occult lung cancer cases. Eight methylated DNA assays were optimised for use with the newly developed Droplet Digitalâ„¢ PCR (ddPCR) platform and a targeted pre-amplification technique, MethPlex enrichment, was developed. I established a comprehensive analytical framework to compare performance of methylation-specific ddPCR and quantitative methylation-specific PCR directly and in combination with MethPlex enrichment. ddPCR demonstrated greater precision and linearity, lower limit of detection (WT1 MethPlex ddPCR LOD95 = 1.86 GE), and discriminated twofold differences in methylated DNA input. MethPlex ddPCR detected DNA methylation more frequently in lung cancer patient plasma than in controls in a retrospective case-control study. Technical methylation controls were consistently and precisely detected at inputs as low as 3 methylated copies. Discriminatory efficiency of marker combinations was inadequate, presumably due to limitations in DNA extraction methodology. DNA methylation biomarker diagnostic performance in bronchoalveolar lavage merits further validation in a prospective trial. MethPlex ddPCR analysis showed great promise, demonstrating highly sensitive DNA methylation detection in technical assessment. It is expected that appropriate DNA extraction procedures and higher cfDNA yields will lead to much improved clinical discriminatory efficiency
Thermodynamic instability of doubly spinning black objects
We investigate the thermodynamic stability of neutral black objects with (at
least) two angular momenta. We use the quasilocal formalism to compute the
grand canonical potential and show that the doubly spinning black ring is
thermodynamically unstable. We consider the thermodynamic instabilities of
ultra-spinning black objects and point out a subtle relation between the
microcanonical and grand canonical ensembles. We also find the location of the
black string/membrane phases of doubly spinning black objects.Comment: 25 pages, 7 figures v2: matches the published versio
A Case-Control Study to Identify Community Venues Associated with Genetically-clustered, Multidrug-resistant Tuberculosis Disease in Lima, Peru
Background: The majority of tuberculosis transmission occurs in community settings. Our primary aim in this study was to assess the association between exposure to community venues and multidrug-resistant (MDR) tuberculosis. Our secondary aim was to describe the social networks of MDR tuberculosis cases and controls. /
Methods: We recruited laboratory-confirmed MDR tuberculosis cases and community controls that were matched on age and sex. Whole-genome sequencing was used to identify genetically clustered cases. Venue tracing interviews (nonblinded) were conducted to enumerate community venues frequented by participants. Logistic regression was used to assess the association between MDR tuberculosis and person-time spent in community venues. A location-based social network was constructed, with respondents connected if they reported frequenting the same venue, and an exponential random graph model (ERGM) was fitted to model the network. /
Results: We enrolled 59 cases and 65 controls. Participants reported 729 unique venues. The mean number of venues reported was similar in both groups (P = .92). Person-time in healthcare venues (adjusted odds ratio [aOR] = 1.67, P = .01), schools (aOR = 1.53, P < .01), and transportation venues (aOR = 1.25, P = .03) was associated with MDR tuberculosis. Healthcare venues, markets, cinemas, and transportation venues were commonly shared among clustered cases. The ERGM indicated significant community segregation between cases and controls. Case networks were more densely connected. /
Conclusions: Exposure to healthcare venues, schools, and transportation venues was associated with MDR tuberculosis. Intervention across the segregated network of case venues may be necessary to effectively stem transmission
Holographic Reconstruction and Renormalization in Asymptotically Ricci-flat Spacetimes
In this work we elaborate on an extension of the AdS/CFT framework to a
subclass of gravitational theories with vanishing cosmological constant. By
building on earlier ideas, we construct a correspondence between Ricci-flat
spacetimes admitting asymptotically hyperbolic hypersurfaces and a family of
conformal field theories on a codimension two manifold at null infinity. By
truncating the gravity theory to the pure gravitational sector, we find the
most general spacetime asymptotics, renormalize the gravitational action,
reproduce the holographic stress tensors and Ward identities of the family of
CFTs and show how the asymptotics is mapped to and reconstructed from conformal
field theory data. In even dimensions, the holographic Weyl anomalies identify
the bulk time coordinate with the spectrum of central charges with
characteristic length the bulk Planck length. Consistency with locality in the
bulk time direction requires a notion of locality in this spectrum.Comment: 44 pages, 4 figures. v2: minor changes in section
Discovery of a recent, natural whale fall on the continental slope off Anvers Island, western Antarctic Peninsula
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Whale falls provide a substantial, nutrient-rich resource for species in areas of the ocean that may otherwise be largely devoid of food. We report the discovery of a natural whale fall at 1430 m depth in the cold waters of the continental slope off the western Antarctic Peninsula. This is the highest-latitude whale fall reported to date. The section of the carcass we observed—the tail fluke—was more complete than any previously reported natural whale fall from the deep sea and in the early stages of decomposition. We estimate the entire cetacean to measure 5–8 m in length. The flesh remained almost intact on the carcass but the skin was missing from the entire section except for the end of the fluke, clearly exposing blubber and soft tissue. The absence of skin indicates rapid and Homogeneous loss. The dominant macrofauna present were crustaceans, including most prominently the lithodid crab Paralomis birsteini, and zoarcid fish typical of the ‘mobile-scavenger’ successional stage. The density of mobile macrofauna was greatest on the carcass and declined to background levels within 100 m, indicating that they were attracted to the whale fall. This whale fall offers an important opportunity to examine the decomposition of a carcass under deep-sea conditions at polar latitudes.We are grateful to the captain and crew of the RV Nathaniel B. Palmer, and to the US Antarctic Support Contractor, Lockheed Martin, for their assistance at sea. We thank J.T. Eastman and two anonymous reviewers for helpful comments on the manuscript. Funding was provided by grants from the U.S. National Science Foundation: ANT-1141877 to R.B.A. and ANT-1141896 to J.B.M. This is contribution 122 from the Institute for Research on Global Climate Change at the Florida Institute of Technology
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