3,688 research outputs found
An Annotated List of the Cerambycidae of Michigan (Coleoptera) Part II, the Subfamilies Lepturinae and Lamiinae
(excerpt)
This is a continuation of Part I of an annotated list of the Cerambycidae known from Michigan, and includes the remaining subfamilies Lepturinae and Lamiinae. The format is similar to that used in Part I. We have largely followed the systematic order of Chemsak and Linsley (1975) in this part of the list. Keys for the identification of adult Lepturinae can be found in Linsley and Chemsak (1972; in press). References to keys for adult Lamiinae are listed under that subfamily. Many larvae may be identified through the keys in Craighead (1923), but not all Michigan species are covere
Complex small-scale structure in the infrared extinction towards the Galactic Centre
A high level of complex structure, or ``granularity'', has been observed in
the distribution of infrared-obscuring material towards the Galactic Centre
(GC), with a characteristic scale of 5arcsec - 15arcsec, corresponding to 0.2 -
0.6pc at a GC distance of 8.5kpc. This structure has been observed in ISAAC
images which have a resolution of 0.6arcsec, significantly higher than that of
previous studies of the GC.
We have discovered granularity throughout the GC survey region, which covers
an area of 1.6deg x 0.8deg in longitude and latitude respectively (300pc x
120pc at 8.5kpc) centred on Sgr A*. This granularity is variable over the whole
region, with some areas exhibiting highly structured extinction in one or more
wavebands and other areas displaying no structure and a uniform stellar
distribution in all wavebands. The granularity does not appear to correspond to
longitude, latitude or radial distance from Sgr A*. We find that regions
exhibiting high granularity are strongly associated with high stellar
reddening.Comment: 5 pages, 3 figures, accepted for publication in ApJ
Over-diagnosis of malaria is not a lost cause.
BACKGROUND: Recent studies have highlighted the over-diagnosis of malaria in clinical settings in Africa. This study assessed the impact of a training programme implemented as part of an intervention trial on diagnostic behaviour of clinicians in a rural district hospital in a low-moderate malaria transmission setting. METHODS: From the beginning of 2005, a randomized controlled trial (RCT) of intermittent preventive treatment for malaria in infants (IPTi) has been conducted at the study hospital. As part of the RCT, the study team offered laboratory quality assurance, and supervision and training of paediatric ward staff using information on malaria epidemiology in the community. Data on clinical and blood slide confirmed cases of malaria from 2001 to 2005 were extracted from the hospital records. RESULTS: The proportion of blood slides positive for malaria parasites had decreased from 21% in 2001 to 7% in 2005 (p < .01). The proportion of outpatient and inpatient cases diagnosed as malaria ranged between 34% and 28% from 2001 to 2004 and this decreased substantially to 17% after the introduction of the package of training and support in 2005 (p < .01). There was no clear trend in the ratio of blood slide examined versus total diagnosis of malaria. CONCLUSION: It may be possible to change the diagnostic behaviour of clinicians by rigorous training using local malaria epidemiology data and supportive supervision
A reiterative method for calculating the early bactericidal activity of antituberculosis drugs.
Studies of early bactericidal activity (EBA) are important in the rapid evaluation of new antituberculosis drugs. Historically, these have concentrated on the log fall in the viable count in sputum during the first 48 hours of therapy. In this paper, we provide a mathematical model that suggests that the viable count in sputum follows an exponential decay curve with the equation V = S + Me(-kt) (where V is the viable count, M the population of bacteria susceptible to the test drug, S the population susceptible only to sterilizing agents, t the day of sputum collection as related to start of therapy, k the rate constant for the bacteria killed each day, and e the Napierian constant). We demonstrate that data from clinical trials fits the exponential decay model. We propose that future EBA studies should be performed by measuring daily quantitative counts for at least 5 days. We also propose that the comparison of the early bactericidal activity of antituberculosis drugs should be evaluated using the time taken to reduce the viable count by 50% (vt(50)). A further reiterative refinement following a rule set based on statistically the best fit to the exponential decay model is described that will allow investigators to identify anomalous results and thus enhance the accuracy in measuring early bactericidal activity
A comparative analysis of projected impacts of climate change on river runoff from global and catchment-scale hydrological models
We present a comparative analysis of projected impacts of climate change on river runoff from two types of distributed hydrological model, a global hydrological model (GHM) and catchment-scale hydrological models (CHM). Analyses are conducted for six catchments that are global in coverage and feature strong contrasts in spatial scale as well as climatic and development conditions. These include the Liard (Canada), Mekong (SE Asia), Okavango (SW Africa), Rio Grande (Brazil), Xiangu (China) and Harper's Brook (UK). A single GHM (Mac-PDM.09) is applied to all catchments whilst different CHMs are applied for each catchment. The CHMs typically simulate water resources impacts based on a more explicit representation of catchment water resources than that available from the GHM, and the CHMs include river routing. Simulations of average annual runoff, mean monthly runoff and high (Q5) and low (Q95) monthly runoff under baseline (1961-1990) and climate change scenarios are presented. We compare the simulated runoff response of each hydrological model to (1) prescribed increases in global mean temperature from the HadCM3 climate model and (2)a prescribed increase in global-mean temperature of 2oC for seven GCMs to explore response to climate model and structural uncertainty.
We find that differences in projected changes of mean annual runoff between the two types of hydrological model can be substantial for a given GCM, and they are generally larger for indicators of high and low flow. However, they are relatively small in comparison to the range of projections across the seven GCMs. Hence, for the six catchments and seven GCMs we considered, climate model structural uncertainty is greater than the uncertainty associated with the type of hydrological model applied. Moreover, shifts in the seasonal cycle of runoff with climate change are presented similarly by both hydrological models, although for some catchments the monthly timing of high and low flows differs.This implies that for studies that seek to quantify and assess the role of climate model uncertainty on catchment-scale runoff, it may be equally as feasible to apply a GHM as it is to apply a CHM, especially when climate modelling uncertainty across the range of available GCMs is as large as it currently is. Whilst the GHM is able to represent the broad climate change signal that is represented by the CHMs, we find, however, that for some catchments there are differences between GHMs and CHMs in mean annual runoff due to differences in potential evaporation estimation methods, in the representation of the seasonality of runoff, and in the magnitude of changes in extreme monthly runoff, all of which have implications for future water management issues
The determination of shock ramp width using the noncoplanar magnetic field component
We determine a simple expression for the ramp width of a collisionless fast
shock, based upon the relationship between the noncoplanar and main magnetic
field components. By comparing this predicted width with that measured during
an observation of a shock, the shock velocity can be determined from a single
spacecraft. For a range of low-Mach, low-beta bow shock observations made by
the ISEE-1 and -2 spacecraft, ramp widths determined from two-spacecraft
comparison and from this noncoplanar component relationship agree within 30%.
When two-spacecraft measurements are not available or are inefficient, this
technique provides a reasonable estimation of scale size for low-Mach shocks.Comment: 6 pages, LaTeX (aguplus + agutex);
packages:amsmath,times,graphicx,float, psfrag,verbatim; 3 postscript figures
called by the file; submitted to Geophys. Res. Let
Measures to increase airfield capacity by changing aircraft runway occupancy characteristics
Airfield capacity and aircraft runway occupancy characteristics were studied. Factors that caused runway congestion and airfield crowding were identified. Several innovations designed to alleviate the congestion are discussed. Integrated landing management, the concept that the operation of the final approach and runway should be considered in concert, was identified as underlying all of the innovations
Can Streamer Blobs prevent the Buildup of the Interplanetetary Magnetic Field?
Coronal Mass Ejections continuously drag closed magnetic field lines away
from the Sun, adding new flux to the interplanetary magnetic field (IMF). We
propose that the outward-moving blobs that have been observed in helmet
streamers are evidence of ongoing, small-scale reconnection in streamer current
sheets, which may play an important role in the prevention of an indefinite
buildup of the IMF. Reconnection between two open field lines from both sides
of a streamer current sheet creates a new closed field line, which becomes part
of the helmet, and a disconnected field line, which moves outward. The blobs
are formed by plasma from the streamer that is swept up in the trough of the
outward moving field line. We show that this mechanism is supported by
observations from SOHO/LASCO. Additionally, we propose a thorough statistical
study to quantify the contribution of blob formation to the reduction of the
IMF, and indicate how this mechanism may be verified by observations with
SOHO/UVCS and the proposed NASA STEREO and ESA Polar Orbiter missions.Comment: 7 pages, 2 figures; accepted by The Astrophysical Journal Letters;
uses AASTe
- …