273 research outputs found
Records of the Australian redclaw crayfish Cherax quadricarinatus (von Martens, 1868) on the island of Puerto Rico
The redclaw crayfish, Cherax quadricarinatus (von Martens, 1868), a tropical freshwater crayfish endemic to Northern Australia and Southern Papua New Guinea, was introduced to the island of Puerto Rico in the late 1990’s. Redclaw has established populations within man-made reservoirs and ponds across the island, where impoundments have impeded the migration and recruitment of native decapods, potentially opening niche space for the redclaw. We present a case study focused on documenting the presence/ absence, sex ratio, size class, and standing stock biomass of redclaw populations from six reservoirs (Carraízo, Cidra, Carite, Güajataca, El Guineo, Dos Bocas), as well as from various holding ponds of an aquaculture facility (Caribe Fisheries) located near the town of Lajas in the southwestern part of the island where the crayfish are considered pests. Crayfish were detected in 5 out of the 7 sample locations (Carraízo, Cidra, Carite, Güajataca, and Caribe Fisheries). A total of N = 150 crayfish were caught during sampling, with 91% being adults (N = 136) and sex counts resulting in a 0.81 male to female ratio. Standard Carapace Length (SCL) ranged from 16 mm (Güajataca) to 82 mm (Carraízo). No significant difference in SCL was found between adult males (48.32 mm ± 1.62 SE) and females (48.17 mm ± 1.47 SE) (F(1,134) = 0.81, P = 0.37), as well as between SCL in M:F ratio among sample sites (F(4,134) = 0.84, P = 0.50). However, a significant difference in total mean SCL among sample sites was found (F(4,134)= 16.96, P < 0.0001). A post-hoc Tukey-Kramer test indicated that individuals in Carraízo, located close to the area of initial redclaw introduction into the headwaters of the Loiza River, had the largest mean SCL (61.38 mm). Mean standing stock biomass per individual ranged from 1.46 g (Güajataca) to 9.71 g (Carraízo). These biomass estimates provide the first insight into the energy supplements that redclaw provides to higher trophic levels (e.g. predatory fish) in these reservoirs. Furthermore, with populations of native decapods having been completely extirpated from most impounded watersheds, introduced redclaw could fill in the empty niche space by processing organic matter and by providing a direct consumption item to recreational fish species. This could reestablish the missing links in the cycling of nutrients and transfer of energy within reservoirs.This project was funded in part by National Science Foundation grants DGE 0841146 and DEB 1139899.Published articl
NUMA Optimizations for Algorithmic Skeletons
To address NUMA performance anomalies, programmers often resort to application specific optimizations that are not transferable to other programs, or to generic optimizations that do not perform well in all cases. Skeleton based programming models allow NUMA optimizations to be abstracted on a pattern-by-pattern basis, freeing programmers from this complexity. As a case study, we investigate computations that can be implemented with stencil skeletons. We present an analysis of the behavior of a range of simple and complex stencil programs from the NAS and Rodinia benchmark suites, under state-of-the-art NUMA aware page placement (PP) schemes. We show that even though an application (or skeleton) may have implemented the correct, intuitive scheduling of data and work to threads, the resulting performance can be disrupted by an inappropriate PP scheme. In contrast, we show that a NUMA PP-aware stencil implementation scheme can achieve speed ups of up to 12x over a similar scheme which uses the Linux default PP, and that this works across a set of complex stencil applications. Furthermore, we show that a supposed PP performance optimization in the Linux kernel never improves and in some cases degrades stencil performance by up to 0.27x and should therefore be deactivated by stencil skeleton implementations. Finally, we show that further speed ups of up to 1.1x can be achieved by addressing a work imbalance issue caused by poor conventional understanding of NUMA PP
Hepatitis C virus quasispecies in chronically infected children subjected to interferon–ribavirin therapy
Accumulating evidence suggests that certain features of hepatitis C virus (HCV), especially its high genetic variability, might be responsible for the low efficiency of anti-HCV treatment. Here, we present a bioinformatic analysis of HCV-1a populations isolated from 23 children with chronic hepatitis C (CHC) subjected to interferon–ribavirin therapy. The structures of the viral quasispecies were established based on a 132-amino-acid sequence derived from E1/E2 protein, including hypervariable region 1 (HVR1). Two types of HCV populations were identified. The first type, found in non-responders, contained a small number of closely related variants. The second type, characteristic for sustained responders, was composed of a large number of distantly associated equal-rank variants. Comparison of 445 HVR1 sequences showed that a significant number of variants present in non-responding patients are closely related, suggesting that certain, still unidentified properties of the pathogen may be key factors determining the result of CHC treatment
Detecting ancient codispersals and host shifts by double dating of host and parasite phylogenies: Application in proctophyllodid feather mites associated with passerine birds
Inferring cophylogeographic events requires matching the timing of these events on both host and symbiont (e.g., parasites) phylogenies because divergences of hosts and their symbionts may not temporally coincide, and host switches may occur. We investigate a large radiation of birds (Passeriformes) and their permanent symbionts, the proctophyllodid feather mites (117 species from 116 bird species; six genes, 11,468 nt aligned) using two time‐calibration strategies for mites: fossils only and host phylogeography only. Out of 10 putative cophylogeographic events 4 agree in timing for both symbiont and host events being synchronous co‐origins or codispersals; three were based on host shifts, but agree in timing being very close to the origin of modern hosts; two disagree; and one large basal mite split was seemingly independent from host phylogeography. Among these events was an ancient (21–25.3 Mya), synchronous codispersal from the Old World leading to the origin and diversifications of New World emberizoid passerids and their mites, the thraupis + quadratus species groups of Proctophyllodes. Our framework offers a more robust detection of host and symbiont cophylogeographic events (as compared to host‐symbiont reconciliation analysis and using host phylogeography for time‐calibration) and provides independent data for testing alternative hypotheses on timing of host diversification and dispersal.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138927/1/evo13309-sup-0003-figureS3.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138927/2/evo13309.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138927/3/evo13309-sup-0006-figureS6.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138927/4/evo13309_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138927/5/evo13309-sup-0009-figureS9.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138927/6/evo13309-sup-0005-figureS5.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138927/7/evo13309-sup-0004-figureS4.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138927/8/evo13309-sup-0002-figureS2.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138927/9/evo13309-sup-0008-figureS8.pd
Speculating China Economic Growth Through Hong Kong? Evidence from the Stock Market IPO and Real Estate Markets
Institutions, banking structure and the cost of debt: new international evidence
We wish to thank participants at the ACEDE Conference in Vigo (2016) for helpful comments and suggestions. Funding from the Spanish Ministry of Economy and Competitiveness via Project ECO2015-66184-R and financial support from the Government of the Principality of Asturias via the Severo Ochoa programme of predoctoral grants are gratefully acknowledged
A 1-Year Prospective French Nationwide Study of Emergency Hospital Admissions in Children and Adults with Primary Immunodeficiency.
PURPOSE: Patients with primary immunodeficiency (PID) are at risk of serious complications. However, data on the incidence and causes of emergency hospital admissions are scarce. The primary objective of the present study was to describe emergency hospital admissions among patients with PID, with a view to identifying "at-risk" patient profiles.
METHODS: We performed a prospective observational 12-month multicenter study in France via the CEREDIH network of regional PID reference centers from November 2010 to October 2011. All patients with PIDs requiring emergency hospital admission were included.
RESULTS: A total of 200 admissions concerned 137 patients (73 adults and 64 children, 53% of whom had antibody deficiencies). Thirty admissions were reported for 16 hematopoietic stem cell transplantation recipients. When considering the 170 admissions of non-transplant patients, 149 (85%) were related to acute infections (respiratory tract infections and gastrointestinal tract infections in 72 (36%) and 34 (17%) of cases, respectively). Seventy-seven percent of the admissions occurred during winter or spring (December to May). The in-hospital mortality rate was 8.8% (12 patients); death was related to a severe infection in 11 cases (8%) and Epstein-Barr virus-induced lymphoma in 1 case. Patients with a central venous catheter (n = 19, 13.9%) were significantly more hospitalized for an infection (94.7%) than for a non-infectious reason (5.3%) (p = 0.04).
CONCLUSION: Our data showed that the annual incidence of emergency hospital admission among patients with PID is 3.4%. The leading cause of emergency hospital admission was an acute infection, and having a central venous catheter was associated with a significantly greater risk of admission for an infectious episode
Promoter hypermethylation and silencing of tissue factor pathway inhibitor-2 in oral squamous cell carcinoma
Global patterns and drivers of ecosystem functioning in rivers and riparian zones
River ecosystems receive and process vast quantities of terrestrial organic carbon, the fate of which depends strongly on microbial activity. Variation in and controls of processing rates, however, are poorly characterized at the global scale. In response, we used a peer-sourced research network and a highly standardized carbon processing assay to conduct a global-scale field experiment in greater than 1000 river and riparian sites. We found that Earth's biomes have distinct carbon processing signatures. Slow processing is evident across latitudes, whereas rapid rates are restricted to lower latitudes. Both the mean rate and variability decline with latitude, suggesting temperature constraints toward the poles and greater roles for other environmental drivers (e.g., nutrient loading) toward the equator. These results and data set the stage for unprecedented "next-generation biomonitoring" by establishing baselines to help quantify environmental impacts to the functioning of ecosystems at a global scale.peerReviewe
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