791 research outputs found

    Reconstructing palaeoflyways of the late Pleistocene and early Holocene Red Knot Calidris canutus

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    Bird migration systems must have changed dramatically during the glacial–interglacial cycles of the Pleistocene and as novel habitats became available since the last glacial maximum. This study combines molecular dating of population divergence times with a review of polar-centred palaeovegetation and intertidal habitats world-wide to present a hypothesis for the evolution of Red Knot Calidris canutus flyways. Divergence dates from coalescent analysis of mitochondrial control region sequences indicate that C. c. canutus diverged from the most recent common ancestor (MRCA) of Red Knots about 20000 (95% CI 60000–4000) years ago. About 12000 (95% CI 45000–3500) years ago this MRCA diverged into two lineages, now represented by the North American breeding C. c. roselaari, C. c. rufa and C. c. islandica and the Siberian breeding C. c. piersmai and C. c. rogersi, respectively. Divergence times of these two Siberian breeding subspecies are about 6500 (95% CI 25000–1000) years ago, and populations of the North American breeding subspecies are estimated to have diverged within about the last 1000 years. These divergence times suggest that all ancestral populations of knots emerged within the last glacial period of the Pleistocene via an eastward expansion into North America. This scenario implies that, contrary to contemporary opinions, C. c. islandica was not recently derived from C. c. canutus despite the fact that they are morphologically similar and that their contemporary migration routes overlap in the Wadden Sea. Instead, C. c. islandica is most closely related to the other North American breeding subspecies C. c. roselaari and C. c. rufa. Thus, C. c. islandica only recently pioneered its current migration route to Europe, following the amelioration of winter conditions in the Wadden Sea and the formation of staging habitat in Iceland. This implies that, in Red Knots at least, the Greenland/Iceland migratory route was established very recently from breeding grounds in the Americas to wintering grounds in Europe and not vice versa as previously believed.

    A Comparison of Producer Gas, Biochar, and Activated Carbon from Two Distributed Scale Thermochemical Conversion Systems used to Process Forest Biomass

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    Thermochemical biomass conversion systems have the potential to produce heat, power, fuels and other products from forest biomass at distributed scales that meet the needs of some forest industry facilities. However, many of these systems have not been deployed in this sector and the products they produce from forest biomass have not been adequately described or characterized with regards to chemical properties, possible uses, and markets. This paper characterizes the producer gas, biochar, and activated carbon of a 700 kg h−1 prototype gasification system and a 225 kg h−1 pyrolysis system used to process coniferous sawmill and forest residues. Producer gas from sawmill residues processed with the gasifier had higher energy content than gas from forest residues, with averages of 2.4 MJ m−3 and 9.8 MJ m−3, respectively. Gases from the pyrolysis system averaged 1.3 MJ m−3 for mill residues and 2.5 MJ m−3 for forest residues. Biochars produced have similar particle size distributions and bulk density, but vary in pH and carbon content. Biochars from both systems were successfully activated using steam activation, with resulting BET surface area in the range of commercial activated carbon. Results are discussed in the context of co-locating these systems with forest industry operations

    Management Outcomes in Splenic Injury: A Statewide Trauma Center Review

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    OBJECTIVE: Clinical pathways now highlight both observation and operation as acceptable initial therapeutic options for the management of patients with splenic injury. The purpose of this study was to evaluate treatment trends for splenic injury in all North Carolina trauma centers over a 6-year period. METHODS: Splenic injuries in adults over a 6-year period (January 1988-December 1993) were identified in the North Carolina Trauma Registry using ICD-9-CM codes. Patients were divided into four groups by method of management: 1) no spleen operation, 2) splenectomy, 3) definitive splenorrhaphy, and 4) splenorrhaphy failure followed by splenectomy. The authors examined age, mechanism of injury, admitting blood pressure, and severity of injury by trauma score and injury severity score. SUMMARY BACKGROUND DATA: Comparisons were made between adult (17-64 years of age) and geriatric (older than 65 years of age) patients and between patients with blunt and penetrating injury. Resource utilization (length of stay, hospital charges) and outcome (mortality) were compared. RESULTS: One thousand two hundred fifty-five patients were identified with splenic injury. Rate of splenic preservation increased over time and was achieved in more than 50% of patients through nonoperative management (40%) and splenorrhaphy (12%). Splenorrhaphy was not used commonly in either blunt or penetrating injury. Overall mortality was 13%. Geriatric patients had a higher mortality and resource utilization regardless of their mechanism of injury or method of management. CONCLUSIONS: Nonoperative management represents the prevailing method of splenic preservation in both the adult and geriatric population in North Carolina trauma center hospitals. Satisfactory outcomes and economic advantages accompany nonoperative management in this adult population

    Global population structure and genotyping framework for genomic surveillance of the major dysentery pathogen, Shigella sonnei.

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    Shigella sonnei is the most common agent of shigellosis in high-income countries, and causes a significant disease burden in low- and middle-income countries. Antimicrobial resistance is increasingly common in all settings. Whole genome sequencing (WGS) is increasingly utilised for S. sonnei outbreak investigation and surveillance, but comparison of data between studies and labs is challenging. Here, we present a genomic framework and genotyping scheme for S. sonnei to efficiently identify genotype and resistance determinants from WGS data. The scheme is implemented in the software package Mykrobe and tested on thousands of genomes. Applying this approach to analyse >4,000 S. sonnei isolates sequenced in public health labs in three countries identified several common genotypes associated with increased rates of ciprofloxacin resistance and azithromycin resistance, confirming intercontinental spread of highly-resistant S. sonnei clones and demonstrating the genomic framework can facilitate monitoring the spread of resistant clones, including those that have recently emerged, at local and global scales

    Fructose transport-deficient Staphylococcus aureus reveals important role of epithelial glucose transporters in limiting sugar-driven bacterial growth in airway surface liquid.

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    Hyperglycaemia as a result of diabetes mellitus or acute illness is associated with increased susceptibility to respiratory infection with Staphylococcus aureus. Hyperglycaemia increases the concentration of glucose in airway surface liquid (ASL) and promotes the growth of S. aureus in vitro and in vivo. Whether elevation of other sugars in the blood, such as fructose, also results in increased concentrations in ASL is unknown and whether sugars in ASL are directly utilised by S. aureus for growth has not been investigated. We obtained mutant S. aureus JE2 strains with transposon disrupted sugar transport genes. NE768(fruA) exhibited restricted growth in 10 mM fructose. In H441 airway epithelial-bacterial co-culture, elevation of basolateral sugar concentration (5-20 mM) increased the apical growth of JE2. However, sugar-induced growth of NE768(fruA) was significantly less when basolateral fructose rather than glucose was elevated. This is the first experimental evidence to show that S. aureus directly utilises sugars present in the ASL for growth. Interestingly, JE2 growth was promoted less by glucose than fructose. Net transepithelial flux of D-glucose was lower than D-fructose. However, uptake of D-glucose was higher than D-fructose across both apical and basolateral membranes consistent with the presence of GLUT1/10 in the airway epithelium. Therefore, we propose that the preferential uptake of glucose (compared to fructose) limits its accumulation in ASL. Pre-treatment with metformin increased transepithelial resistance and reduced the sugar-dependent growth of S. aureus. Thus, epithelial paracellular permeability and glucose transport mechanisms are vital to maintain low glucose concentration in ASL and limit bacterial nutrient sources as a defence against infection

    Assessing Local Health Department Performance in Diabetes Prevention and Control — North Carolina, 2005

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    Introduction: To improve the public health system's ability to prevent and control chronic diseases, we must first understand current practice and develop appropriate strategies for measuring performance. The objectives of this study were to measure capacity and performance of local health departments in diabetes prevention and control and to investigate characteristics associated with performance. Methods: In 2005, we conducted a cross-sectional mailed survey of all 85 North Carolina local health departments to assess capacity and performance in diabetes prevention and control based on the 10 Essential Public Health Services and adapted from the Local Public Health System Performance Assessment Instrument. We linked survey responses to county-level data, including data from a national survey of local health departments. Results: Local health departments reported a median of 0.05 full-time equivalent employees in diabetes prevention and 0.1 in control. Performance varied across the 10 Essential Services; activities most commonly reported included providing information to the public and to policy makers (76%), providing diabetes education (58%), and screening (74%). The mean score on a 10-point performance index was 3.5. Characteristics associated with performance were population size, health department size and accreditation status, and diabetes-specific external funding. Performance was not better in localities where the prevalence of diabetes was high or availability of primary care was low. Conclusion: Most North Carolina local health departments had limited capacity to conduct diabetes prevention or control programs in their communities. Diabetes is a major cause of illness and death, yet it is neglected in public health practice. These findings suggest opportunities to enhance local public health practice, particularly through targeted funding and technical assistance

    Effect of a Multidisciplinary Team Approach to Eradicate Central Line Associated Blood-Stream Infections (CLABSI)

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    Introduction: CLABSI remains a significant problem in the intensive care unit. Hypothesis: A multimodal approach for the insertion and care of CVC will prevent CLABSI. Methods: A Critical Care Operations Committee was formed to transform care in 8 intensive care units (ICU) in an academic medical center in 9/2004. One goal was to reduce CLABSI. Using evidence based medicine, a clinical practice guideline was developed that incorporated the use of maximum barrier precautions, chlorhexidine skin preparation, avoidance of the femoral insertion site, dedicated catheter cart, a check list, the tracking of high risk CVC, anti-septic or antimicrobial impregnated catheters, a recommendation to use ultrasound guidance when inserting CVC in the internal jugular vein, daily determination of the need for the CVC and treatment of CLABSI as a critical event.CLABSI were adjudicated by the hospital epidemiologist and CVC days were tracked. Rates of CLABSI were followed from 9/2004 through 7/2011. The Spearman correlation coefficient was used for statistical evaluation. A p Results: CLABSI rates (per 1000 catheter-days) declined dramatically from 2004 to 2011 (p Conclusions: A multimodal approach to CVC insertion and care reduces CLABSI by over 90%. Our ultimate goal is the complete eradication of CRBSI in our institution
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