652 research outputs found

    Spatial Distributions of Three Species of Desmognathus in a North Carolina Stream

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    Salamanders of the family Plethodontidae comprise the most common salamanders in eastern North America. It is not uncommon for more than 10 plethodontid species to occur syntopically in one creek. The purpose of this research was to determine whether the spatial distribution of one species affected the spatial distribution of other species. Geographic Information System technology and nearest-neighbor analyses were used to determine the spatial distributions of three species of the salamander genus Desmognathus. The analysis demonstrates that D. ochrophaeus and D. monticola change their spatial use from a random distribution during the day to a clumped distribution during evening hours. The data also suggest the D. monticola moves into the creek during evening hours

    Incidence and severity of respiratory syncytial virus pneumonia in rural Kenyan children identified through hospital surveillance

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    Background.Although necessary for developing a rationale for vaccination, the burden of severe respiratory syncytial virus (RSV) disease in children in resourceā€poor settings remains poorly defined. Methods.We conducted prospective surveillance of severe and very severe pneumonia in children aged <5 years admitted from 2002 through 2007 to Kilifi district hospital in coastal Kenya. Nasal specimens were screened for RSV antigen by immunofluorescence. Incidence rates were estimated for the wellā€defined population. Results.Of 25,149 hospital admissions, 7359 patients (29%) had severe or very severe pneumonia, of whom 6026 (82%) were enrolled. RSV prevalence was 15% (20% among infants) and 27% during epidemics (32% among infants). The proportion of case patients aged 3 months was 65%, and the proportion aged 6 months was 43%. Average annual hospitalization rates were 293 hospitalizations per 100,000 children aged <5 years (95% confidence interval, 271ā€“371 hospitalizations per 100,000 children aged <5 years) and 1107 hospitalizations per 100,000 infants (95% confidence interval, 1012ā€“1211 hospitalizations per 100,000 infants). Hospital admission rates were double in the region close to the hospital. Few patients with RSV infection had lifeā€threatening clinical features or concurrent serious illnesses, and the associated mortality was 2.2%. Conclusions.In this lowā€income setting, rates of hospital admission with RSVā€associated pneumonia are substantial; they are comparable to estimates from the United States but considerably underestimate the burden in the full community. An effective vaccine for children aged >2 months (outside the age group of poor responders) could prevent a large portion of RSV disease. Severity data suggest that the justification for RSV vaccination will be based on the prevention of morbidity, not mortality

    Genetic Variability in Developing Periodical Cicadas

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    There are few events in nature that are more predictable than the emergence of periodical cicadas. The insects emerge from the ground after 13 or 17 years (depending on brood and species) of development. Karlin et al., (1991) biochemically examined over 750 Magicicada tredecassini belonging to Brood XIX which emerged during the spring of 1985. In this study they found evidence for rapid deterioration of heterozygosity for two esterase loci,Gi-3-pdh and Gpi, and suggested that this deterioration may be related to differential mating classes. To test this hypothesis, we re-sampled from this same brood at the same location during fall (1993) and winter (1994), nine years into the 13 year development of this brood. The current biochemical data suggest no significant deviations from Hardy-Weinberg expectations for either Est-3, Gl-3- pdh or Pgm-1, but in several cases Est-1 or Est-2 displayed significant departures. Our failure to find excess heterozygosity in the nymphal sample is interpreted to support weakly the size-mediated mating system hypothesis

    Advanced power sources for space missions

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    Approaches to satisfying the power requirements of space-based Strategic Defense Initiative (SDI) missions are studied. The power requirements for non-SDI military space missions and for civil space missions of the National Aeronautics and Space Administration (NASA) are also considered. The more demanding SDI power requirements appear to encompass many, if not all, of the power requirements for those missions. Study results indicate that practical fulfillment of SDI requirements will necessitate substantial advances in the state of the art of power technology. SDI goals include the capability to operate space-based beam weapons, sometimes referred to as directed-energy weapons. Such weapons pose unprecedented power requirements, both during preparation for battle and during battle conditions. The power regimes for these two sets of applications are referred to as alert mode and burst mode, respectively. Alert-mode power requirements are presently stated to range from about 100 kW to a few megawatts for cumulative durations of about a year or more. Burst-mode power requirements are roughly estimated to range from tens to hundreds of megawatts for durations of a few hundred to a few thousand seconds. There are two likely energy sources, chemical and nuclear, for powering SDI directed-energy weapons during the alert and burst modes. The choice between chemical and nuclear space power systems depends in large part on the total duration during which power must be provided. Complete study findings, conclusions, and eight recommendations are reported

    Defining childhood severe falciparum malaria for intervention studies.

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    Background Clinical trials of interventions designed to prevent severe falciparum malaria in children require a clear endpoint. The internationally accepted definition of severe malaria is sensitive, and appropriate for clinical purposes. However, this definition includes individuals with severe nonmalarial disease and coincident parasitaemia, so may lack specificity in vaccine trials. Although there is no ā€œgold standardā€ individual test for severe malaria, malaria-attributable fractions (MAFs) can be estimated among groups of children using a logistic model, which we use to test the suitability of various case definitions as trial endpoints. Methods and Findings A total of 4,583 blood samples were taken from well children in cross-sectional surveys and from 1,361 children admitted to a Kenyan District hospital with severe disease. Among children under 2 y old with severe disease and over 2,500 parasites per microliter of blood, the MAFs were above 85% in moderate- and low-transmission areas, but only 61% in a high-transmission area. HIV and malnutrition were not associated with reduced MAFs, but gastroenteritis with severe dehydration (defined by reduced skin turgor), lower respiratory tract infection (clinician's final diagnosis), meningitis (on cerebrospinal fluid [CSF] examination), and bacteraemia were associated with reduced MAFs. The overall MAF was 85% (95% confidence interval [CI] 83.8%ā€“86.1%) without excluding these conditions, 89% (95% CI 88.4%ā€“90.2%) after exclusions, and 95% (95% CI 94.0%ā€“95.5%) when a threshold of 2,500 parasites/Ī¼l was also applied. Applying a threshold and exclusion criteria reduced sensitivity to 80% (95% CI 77%ā€“83%). Conclusions The specificity of a case definition for severe malaria is improved by applying a parasite density threshold and by excluding children with meningitis, lower respiratory tract infection (clinician's diagnosis), bacteraemia, and gastroenteritis with severe dehydration, but not by excluding children with HIV or malnutrition

    Use of clinical syndromes to target antibiotic prescribing in seriously ill children in malaria endemic area: observational study.

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    OBJECTIVES: To determine how well antibiotic treatment is targeted by simple clinical syndromes and to what extent drug resistance threatens affordable antibiotics. DESIGN: Observational study involving a priori definition of a hierarchy of syndromic indications for antibiotic therapy derived from World Health Organization integrated management of childhood illness and inpatient guidelines and application of these rules to a prospectively collected dataset. SETTING: Kilifi District Hospital, Kenya. PARTICIPANTS: 11,847 acute paediatric admissions. MAIN OUTCOME MEASURES: Presence of invasive bacterial infection (bacteraemia or meningitis) or Plasmodium falciparum parasitaemia; antimicrobial sensitivities of isolated bacteria. RESULTS: 6254 (53%) admissions met criteria for syndromes requiring antibiotics (sick young infants; meningitis/encephalopathy; severe malnutrition; very severe, severe, or mild pneumonia; skin or soft tissue infection): 672 (11%) had an invasive bacterial infection (80% of all invasive bacterial infections identified), and 753 (12%) died (93% of all inpatient deaths). Among P falciparum infected children with a syndromic indication for parenteral antibiotics, an invasive bacterial infection was detected in 4.0-8.8%. For the syndrome of meningitis/encephalopathy, 96/123 (76%) isolates were fully sensitive in vitro to penicillin or chloramphenicol. CONCLUSIONS: Simple clinical syndromes effectively target children admitted with invasive bacterial infection and those at risk of death. Malaria parasitaemia does not justify withholding empirical parenteral antibiotics. Lumbar puncture is critical to the rational use of antibiotics

    Reliability of Unilateral Isometric and Dynamic Leg Press Force and Power

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    Strength and power are critical components of athletic performance. Athletes commonly perform sport-specific movements off a single leg, but there are few reliable, easily administered unilateral leg force and power assessments. PURPOSE: To determine 1) the reliability of unilateral leg press maximal isometric force (MIF) and peak power tests and 2) the percentage of MIF that elicits unilateral peak power during a dynamic throw. We hypothesized that the tests would be reliable for the assessment of unilateral MIF and peak power and that unilateral peak power would be achieved at 50% of MIF. METHODS: Eighteen apparently healthy, recreationally active adults (17M: 1F; 27.4 Ā± 5.0 years; 1.78 Ā± 0.01 m; 93.5 Ā± 22.5 kg; 3159 Ā± 807 N bilateral MIF) completed three testing sessions. After a brief standardized warm-up, each subject performed three maximal unilateral isometric leg presses (MIF) with each leg at 90Ā° of knee flexion on a modified leg press sled equipped with a force plate, linear encoder, and magnetic brake. Subsequently, the sled was unlocked and loaded in ascending fashion with 30%, 40%, 50%, 60%, and 70% of MIF; with an initial knee angle of 90Ā°, subjects used maximal effort to throw each load twice, unilaterally, with each leg. Subjects rested and reset for 10-30 s between efforts. Data were sampled at 300 Hz, low pass filtered at 4 Hz, and peak instantaneous power (W) was calculated for each throw using the measured sled force and velocity. Intraclass correlation coefficients (ICC) were computed for the highest force and power repetition at each load across the three sessions. The ICC (95% CI) and peak power output were determined for both right and left legs. ICCs were considered excellent if ā‰„ 0.95, high if ā‰„ 0.90, good if ā‰„ 0.80, fair if ā‰„ 0.70, poor if ā‰¤ 0.70, and very poor if ā‰¤ 0.40. RESULTS: MIF showed good reliability between sessions [ICC: 0.85 (0.62, 0.94; left leg); 0.86 (0.58, 0.95; right leg)]. Unilateral peak power also showed good to high reliability between sessions across all loads: ICC (left leg) 30%: 0.91 (0.81, 0.96); 40%: 0.91 (0.81, 0.96); 50%: 0.95 (0.88, 0.98); 60%: 0.93 (0.86, 0.97); 70%: 0.81 (0.64, 0.92); (right leg) 30%: 0.95 (0.89, 0.98); 40%: 0.94 (0.87, 0.97); 50%: 0.92 (0.84, 0.97); 60%: 0.92 (0.84, 0.97); 70%: 0.90 (0.80, 0.96). Across all three sessions, peak power by the left leg was achieved at: 30% (11 of 18 participants); 40% (6 of 18); 50% (1 of 18). Peak power by the right leg was achieved at: 30% (13 of 18 participants); 40% (4 of 18); 50% (1 of 18). CONCLUSION: Unilateral leg press MIF and peak power can be reliably assessed with a modified leg press equipped with a force plate, linear encoder, and magnetic brake in a recreationally active population. Sport teams and coaches can use single leg isometric presses and throws as reliable methods to test their athletesā€™ unilateral force and peak power, respectively, with loads of 30-50% MIF appropriate for peak power measurement

    Morally Respectful Listening and its Epistemic Consequences

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    What does it mean to listen to someone respectfully, that is, insofar as they are due recognition respect? This paper addresses that question and gives the following answer: it is to listen in such a way that you are open to being surprised. A specific interpretation of this openness to surprise is then defended

    Development of paediatric quality of inpatient care indicators for low-income countries - A Delphi study

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    BACKGROUND: Indicators of quality of care for children in hospitals in low-income countries have been proposed, but information on their perceived validity and acceptability is lacking. METHODS: Potential indicators representing structural and process aspects of care for six common conditions were selected from existing, largely qualitative WHO assessment tools and guidelines. We employed the Delphi technique, which combines expert opinion and existing scientific information, to assess their perceived validity and acceptability. Panels of experts, one representing an international panel and one a national (Kenyan) panel, were asked to rate the indicators over 3 rounds and 2 rounds respectively according to a variety of attributes. RESULTS: Based on a pre-specified consensus criteria most of the indicators presented to the experts were accepted: 112/137(82%) and 94/133(71%) for the international and local panels respectively. For the other indicators there was no consensus; none were rejected. Most indicators were rated highly on link to outcomes, reliability, relevance, actionability and priority but rated more poorly on feasibility of data collection under routine conditions. There was moderate to substantial agreement between the two panels of experts. CONCLUSIONS: This Delphi study provided evidence for the perceived usefulness of most of a set of measures of quality of hospital care for children proposed for use in low-income countries. However, both international and local experts expressed concerns that data for many process-based indicators may not currently be available. The feasibility of widespread quality assessment and responsiveness of indicators to intervention should be examined as part of continued efforts to improve approaches to informative hospital quality assessment
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