3,984 research outputs found
You’re a Trustee -- Now What?
The article talks about the public library trustees appointed by local funding agencies of the library system in the U.S. The funding agencies in Henry County, Georgia are the Board of Commissioners and the Board of Education. Trustees have a library director who has an advanced degree in library science and who has participated in ongoing staff development activities to learn new tricks and trends. They also have fellow board members and a state library agency, which is the Georgia Public Library Service. Important factors to remember about the responsibilities of trustees are mentioned
Vertical Field-Effect Transistor Based on Wavefunction Extension
We demonstrate a mechanism for a dual layer, vertical field-effect
transistor, in which nearly-depleting one layer will extend its wavefunction to
overlap the other layer and increase tunnel current. We characterize this
effect in a specially designed GaAs/AlGaAs device, observing a tunnel current
increase of two orders of magnitude at cryogenic temperatures, and we suggest
extrapolations of the design to other material systems such as graphene
A New Technique for Firn Grain-Size Measurement Using SEM Image Analysis
Firn microstructure is accurately characterized using images obtained from scanning electron microscopy (SEM). Visibly etched grain boundaries within images are used to create a skeleton outline of the microstructure. A pixel-counting utility is applied to the outline to determine grain area. Firn grain sizes calculated using the technique described here are compared to those calculated using the techniques of Cow (1969) and Gay and Weiss (1999) on samples of the same material, and are found to be substantially smaller. The differences in grain size between the techniques are attributed to sampling deficiencies (e.g. the inclusion of pore filler in the grain area) in earlier methods. The new technique offers the advantages of greater accuracy and the ability to determine individual components of the microstructure (grain and pore), which have important applications in ice-core analyses. The new method is validated by calculating activation energies of grain boundary diffusion using predicted values based on the ratio of grain-size measurements between the new and existing techniques. The resulting activation energy falls within the range of values previously reported for firn/ice
Neutrophils from Both Susceptible and Resistant Mice Efficiently Kill Opsonized \u3cem\u3eListeria monocytogenes\u3c/em\u3e
Inbred mouse strains differ in their susceptibility to infection with the facultative intracellular bacterium Listeria monocytogenes, largely due to delayed or deficient innate immune responses. Previous antibody depletion studies suggested that neutrophils (polymorphonuclear leukocytes [PMN]) were particularly important for clearance in the liver, but the ability of PMN from susceptible and resistant mice to directly kill L. monocytogenes has not been examined. In this study, we showed that PMN infiltrated the livers of BALB/c/By/J (BALB/c) and C57BL/6 (B6) mice in similar numbers and that both cell types readily migrated toward leukotriene B4 in an in vitro chemotaxis assay. However, CFU burdens in the liver were significantly higher in BALB/c mice than in other strains, suggesting that PMN in the BALB/c liver might not be able to clear L. monocytogenes as efficiently as B6 PMN. Unprimed PMN harvested from either BALB/c or B6 bone marrow killed L. monocytogenes directly ex vivo, and pretreatment with autologous serum significantly enhanced killing efficiency for both. L. monocytogenes were internalized within 10 min and rapidly triggered intracellular production of reactive oxygen species in a dose-dependent manner. However, PMN from gp91phox-deficient mice also readily killed L. monocytogenes, which suggested that nonoxidative killing mechanisms may be sufficient for bacterial clearance. Together, these results indicate that there is not an intrinsic defect in the ability of PMN from susceptible BALB/c mice to kill L. monocytogenes and further suggest that if PMN function is impaired in BALB/c mice, it is likely due to locally produced modulating factors present in the liver during infection
Health deficits in community dwelling adults aged 40 to 75 years
Background: Middle and older years are associated with age related health deficits but how early this begins and progresses is poorly understood. Better understanding is needed to address early decline and support healthier ageing outcomes. Methods: Seemingly healthy, community dwelling adults aged 40 to 75 years were recruited via local council and business networks. They completed online surveys about sleep quality, distress and physical activity, and two hours of objective testing of physiologic and anthropometric measures, mobility, cognition, grip strength, foot sensation, dexterity and functional hearing. Analysis compared outcomes for age, gender, and age and gender groups with population norms for 21 health assessments. The total number of non-compliant tests for each participant was calculated by summing the number of non-compliant tests, and the frequency of these scores across the sample was reported. Gender and age effects were tested using ANOVA models. Combined age and gender categories were used for subsequent logistic regression modelling, with females aged 40-49 years being the default comparator. Results: Of 561 participants (67% female; mean age 60 years (SD 10.3)), everyone had at least one deficit and median deficits was 5 (IQR 2). More than 50% of participants did not meet anthropometric and exercise norms, while 30 to 40% had reduced functional hearing and cognition. Overall, men performed worse and deficits increased with age particularly for physical activity, audiology, mobility, anthropometry, oximetry and foot sensation. Heart rate, body temperature and dyspnoea were the only variables where compliance was within 95% of expected values. Multiple areas of functional decline were found in people aged in their 40s and 50s. Conclusions: The health deficits identified are mostly mutable hence identification and interventions to address the multi-system functional decline in people as young as 40 has the capacity to ensure healthier ageing.Susan Gordon, Michael Kidd, Anthony Maeder, Nicky Baker, Tania Marin, and Karen Grimme
The burden and characteristics of enteric fever at a healthcare facility in a densely populated area of Kathmandu
Enteric fever, caused by Salmonella enterica serovars Typhi and Paratyphi A (S. Typhi and S. Paratyphi A) remains a major public health problem in many settings. The disease is limited to locations with poor sanitation which facilitates the transmission of the infecting organisms. Efficacious and inexpensive vaccines are available for S. Typhi, yet are not commonly deployed to control the disease. Lack of vaccination is due partly to uncertainty of the disease burden arising from a paucity of epidemiological information in key locations. We have collected and analyzed data from 3,898 cases of blood culture-confirmed enteric fever from Patan Hospital in Lalitpur Sub-Metropolitan City (LSMC), between June 2005 and May 2009. Demographic data was available for a subset of these patients (n = 527) that were resident in LSMC and who were enrolled in trials. We show a considerable burden of enteric fever caused by S. Typhi (2,672; 68.5%) and S. Paratyphi A (1,226; 31.5%) at this Hospital over a four year period, which correlate with seasonal fluctuations in rainfall. We found that local population density was not related to incidence and we identified a focus of infections in the east of LSMC. With data from patients resident in LSMC we found that the median age of those with S. Typhi (16 years) was significantly less than S. Paratyphi A (20 years) and that males aged 15 to 25 were disproportionately infected. Our findings provide a snapshot into the epidemiological patterns of enteric fever in Kathmandu. The uneven distribution of enteric fever patients within the population suggests local variation in risk factors, such as contaminated drinking water. These findings are important for initiating a vaccination scheme and improvements in sanitation. We suggest any such intervention should be implemented throughout the LSMC area.This work was supported by The Wellcome Trust, Euston Road, London, United Kingdom. MFB is supported by the Medical Research Council (grant
G0600718). SB is supported by an OAK foundation fellowship through Oxford University
Beta-band intermuscular coherence:A novel biomarker of upper motor neuron dysfunction in motor neuron disease
In motor neuron disease, the focus of therapy is to prevent or slow neuronal degeneration with neuroprotective pharmacological agents; early diagnosis and treatment are thus essential. Incorporation of needle electromyographic evidence of lower motor neuron degeneration into diagnostic criteria has undoubtedly advanced diagnosis, but even earlier diagnosis might be possible by including tests of subclinical upper motor neuron disease. We hypothesized that beta-band (15-30Hz) intermuscular coherence could be used as an electrophysiological marker of upper motor neuron integrity in such patients. We measured intermuscular coherence in eight patients who conformed to established diagnostic criteria for primary lateral sclerosis and six patients with progressive muscular atrophy, together with 16 age-matched controls. In the primary lateral sclerosis variant of motor neuron disease, there is selective destruction of motor cortical layer V pyramidal neurons and degeneration of the corticospinal tract, without involvement of anterior horn cells. In progressive muscular atrophy, there is selective degeneration of anterior horn cells but a normal corticospinal tract. All patients with primary lateral sclerosis had abnormal motor-evoked potentials as assessed using transcranial magnetic stimulation, whereas these were similar to controls in progressive muscular atrophy. Upper and lower limb intermuscular coherence was measured during a precision grip and an ankle dorsiflexion task, respectively. Significant beta-band coherence was observed in all control subjects and all patients with progressive muscular atrophy tested, but not in the patients with primary lateral sclerosis. We conclude that intermuscular coherence in the 15-30Hz range is dependent on an intact corticospinal tract but persists in the face of selective anterior horn cell destruction. Based on the distributions of coherence values measured from patients with primary lateral sclerosis and control subjects, we estimated the likelihood that a given measurement reflects corticospinal tract degeneration. Therefore, intermuscular coherence has potential as a quantitative test of subclinical upper motor neuron involvement in motor neuron disease
Hemisystems of small flock generalized quadrangles
In this paper, we describe a complete computer classification of the
hemisystems in the two known flock generalized quadrangles of order
and give numerous further examples of hemisystems in all the known flock
generalized quadrangles of order for . By analysing the
computational data, we identify two possible new infinite families of
hemisystems in the classical generalized quadrangle .Comment: slight revisions made following referee's reports, and included raw
dat
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