557 research outputs found
An improved mosquito electrocuting trap that safely reproduces epidemiologically relevant metrics of mosquito human-feeding behaviours as determined by human landing catch
Background:
Reliable quantification of mosquito host—seeking behaviours is required to determine the efficacy of vector control methods. For malaria, the gold standard approach remains the risky human landing catch (HLC). Here compare the performance of an improved prototype of the mosquito electrocuting grid trap (MET) as a safer alternative with HLC for measuring malaria vector behaviour in Dar es Salaam, Tanzania.
Methods:
Mosquito trapping was conducted at three sites within Dar es Salaam representing a range of urbanicity over a 7-month period (December 2012–July 2013, 168 sampling nights). At each site, sampling was conducted in a block of four houses, with two houses being allocated to HLC and the other to MET on each night of study. Sampling was conducted both indoors and outdoors (from 19:00 to 06:00 each night) at all houses, with trapping method (HLC and MET) being exchanged between pairs of houses at each site using a crossover design.
Results:
The MET caught significantly more Anopheles gambiae sensu lato than the HLC, both indoors (RR [95 % confidence interval (CI)]) = 1.47 [1.23–1.76], P < 0.0001 and outdoors = 1.38 [1.14–1.67], P < 0.0001). The sensitivity of MET compared with HLC did not detectably change over the course of night for either An. gambiae s.l. (OR [CI]) = 1.01 [0.94–1.02], P = 0.27) or Culex spp. (OR [CI]) = 0.99 [0.99–1.0], P = 0.17) indoors and declined only slightly outdoors: An. gambiae s.l. (OR [CI]) = 0.92 [0.86–0.99], P = 0.04), and Culex spp. (OR [CI]) = 0.99 [0.98–0.99], P = 0.03). MET-based estimates of the proportions of mosquitoes caught indoors (P i ) or during sleeping hours (P fl ), as well as the proportion of human exposure to bites that would otherwise occurs indoors (π i ), were statistically indistinguishable from those based on HLC for An. gambiae s.l. (P = 0.43, 0.07 and 0.48, respectively) and Culex spp. (P = 0.76, 0.24 and 0.55, respectively).
Conclusions:
This improved MET prototype is highly sensitive tool that accurately quantifies epidemiologically-relevant metrics of mosquito biting densities, behaviours and human exposure distribution
Effects of quality grade, aging period, blade tenderization, and degree of doneness on tenderness of inside round steaks
We used 162 inside rounds to determine the
influence of different quality grades, postmortem
aging periods, blade tenderization passes, and
degree of doneness on thawing and cooking
losses and Warner-Bratzler Shear force (WBS,
tenderness). Select (SEL), Choice (CHO), and
Certified Angus Beef™ (CAB) inside rounds
were aged for 7, 14, or 21 days and not tenderized
(0X) or blade tenderized one (1X) or two
(2X) times. Steaks from each inside round
were assigned randomly to final endpoint cooking
temperatures of 150, 160, and 170°F.
Percentage of thawing loss was higher (P<.05)
for steaks aged 7 days than steaks aged 14 and
21 days. For CHO steaks only, cooking loss
was higher (P<.05) for the 2X group compared
to the 0X and 1X groups. Steaks aged 14 and
21 days had lower (P<.05) WBS than steaks
aged 7 days. Cooking loss and WBS were
higher (P<.05) with each increase in endpoint
cooking temperature. Postmortem aging (14 or
21 days) and lower endpoint cooking temperatures
were the most effective methods to improve
WBS of inside round steaks
L^{2}-restriction bounds for eigenfunctions along curves in the quantum completely integrable case
We show that for a quantum completely integrable system in two dimensions,the
-normalized joint eigenfunctions of the commuting semiclassical
pseudodifferential operators satisfy restriction bounds ofthe form for generic
curves on the surface. We also prove that the maximal restriction
bounds of Burq-Gerard-Tzvetkov are always attained for certain exceptional
subsequences of eigenfunctions.Comment: Correct some typos and added some more detail in section
Subglacial bedforms reveal an exponential size-frequency distribution
Subglacial bedforms preserved in deglaciated landscapes record characteristics of past ice-sediment flow regimes, providing insight into subglacial processes and ice sheet dynamics. Individual forms vary considerably, but they can often be grouped into coherent fields, typically called flow-sets, that reflect discrete episodes of ice flow. Within these, bedform size-frequency distributions (predominantly height, width and length) are currently described by several statistics (e.g., mean, median, and standard deviation) that, arguably, do not best capture the defining characteristics of these populations. This paper seeks to create a better description based upon semi-log plots, which reveal that the frequency distributions of bedform dimensions (drumlin, mega-scale glacial lineation, and ribbed moraine) plot as straight lines above the mode (φ). This indicates, by definition, an exponential distribution, for which a simple and easily calculated, yet statistically rigorous, description is designed. Three descriptive parameters are proposed: gradient (λ; the exponent, characterising bedforms likely least affected by non-glacial factors), area-normalised y-intercept (β; quantifying spatial density), and the mode (φ). Below φ, small features are less prevalent due to i) measurement: data, sampling and mapping fidelity; ii) possible post-glacial degradation; or iii) genesis: not being created sub-glacially. This new description has the benefit of being insensitive to the impact of potentially unmapped or degraded smaller features and better captures properties relating to ice flow. Importantly, using λ, flow sets can now be more usefully compared with each other across all deglaciated regions and with the output of numerical ice sheet models. Applications may also exist for analogous fluvial and aeolian bedforms. Identifying the characteristic exponential and that it is typical of 'emergent' subglacial bedforms is a new and potentially powerful constraint on their genesis, perhaps indicating that ice-sediment interaction is fundamentally stochastic in nature. © 2013 Elsevier B.V
Genetic partitioning of interleukin-6 signalling in mice dissociates Stat3 from Smad3-mediated lung fibrosis
Idiopathic pulmonary fibrosis (IPF) is a fatal disease that is unresponsive to current therapies and characterized by excessive collagen deposition and subsequent fibrosis. While inflammatory cytokines, including interleukin (IL)-6, are elevated in IPF, the molecular mechanisms that underlie this disease are incompletely understood, although the development of fibrosis is believed to depend on canonical transforming growth factor (TGF)-β signalling. We examined bleomycin-induced inflammation and fibrosis in mice carrying a mutation in the shared IL-6 family receptor gp130. Using genetic complementation, we directly correlate the extent of IL-6-mediated, excessive Stat3 activity with inflammatory infiltrates in the lung and the severity of fibrosis in corresponding gp130757F mice. The extent of fibrosis was attenuated in B lymphocyte-deficient gp130757F;µMT−/− compound mutant mice, but fibrosis still occurred in their Smad3−/− counterparts consistent with the capacity of excessive Stat3 activity to induce collagen 1α1 gene transcription independently of canonical TGF-β/Smad3 signalling. These findings are of therapeutic relevance, since we confirmed abundant STAT3 activation in fibrotic lungs from IPF patients and showed that genetic reduction of Stat3 protected mice from bleomycin-induced lung fibrosis
Mission Concept for the Single Aperture Far-Infrared (SAFIR) Observatory
The Single Aperture Far-InfraRed (SAFIR) Observatory's science goals are
driven by the fact that the earliest stages of almost all phenomena in the
universe are shrouded in absorption by and emission from cool dust and gas that
emits strongly in the far-infrared and submillimeter. Over the past several
years, there has been an increasing recognition of the critical importance of
this spectral region to addressing fundamental astrophysical problems, ranging
from cosmological questions to understanding how our own Solar System came into
being. The development of large, far-infrared telescopes in space has become
more feasible with the combination of developments for the James Webb Space
Telescope and of enabling breakthroughs in detector technology. We have
developed a preliminary but comprehensive mission concept for SAFIR, as a 10
m-class far-infrared and submillimeter observatory that would begin development
later in this decade to meet the needs outlined above. Its operating
temperature (<4K) and instrument complement would be optimized to reach the
natural sky confusion limit in the far-infrared with diffraction-limited
peformance down to at least 40 microns. This would provide a point source
sensitivity improvement of several orders of magnitude over that of Spitzer or
Herschel, with finer angular resolution, enabling imaging and spectroscopic
studies of individual galaxies in the early universe. We have considered many
aspects of the SAFIR mission, including the telescope technology, detector
needs and technologies, cooling method and required technology developments,
attitude and pointing, power systems, launch vehicle, and mission operations.
The most challenging requirements for this mission are operating temperature
and aperture size of the telescope, and the development of detector arrays.Comment: 36 page
Indirect learning: how emerging-market firms grow in developed markets
Some emerging-market firms have recently achieved substantial growth in developed markets despite having had little prior experience in these markets. What explains the performance of these firms? Building on the organizational learning literature, the authors argue that indirect learning (i.e., learning from the experience of others) plays a crucial role in explaining this phenomenon. Specifically, they propose that emerging-market firms that grow in developed markets overcome their lack of direct experience in such markets by learning indirectly through their leaders, competitors, and interfirm networks. The authors test their thesis by comparing the international growth in developed markets of a sample of emerging-market firms (116 Indian firms) with a sample of developed-market firms (160 U.K. firms). The results support the authors' thesis about the importance of indirect learning in explaining the international growth of emerging-market (relative to developed-market) firms in developed markets. The authors discuss the implications of these findings for policy makers in the areas of higher education, competition policy, and international trade as well as for managers in the areas of middle-management recruitment, competitor analysis and tracking, and managing interfirm networks
An ice-sheet scale comparison of eskers with modelled subglacial drainage routes
Eskers record a time-integrated signature of channelised meltwater drainage during
deglaciation providing vital information on the nature and evolution of subglacial drainage. In this
paper, we compare the spatial pattern of eskers beneath the former Laurentide Ice Sheet with
subglacial drainage routes diagnosed at discrete time intervals from the results of a numerical icesheet
model. Perhaps surprisingly, we show that eskers predominantly occur in regions where
modelled subglacial water flow is low. Eskers and modelled subglacial drainage routes were found to
typically match for lengths <10 km, and most eskers show a better agreement with the routes close to
the ice margin just prior to deglaciation. This supports a time-transgressive esker pattern, with
formation in short (<10 km) segments of conduit close behind a retreating ice margin, and probably
associated with thin, stagnant or sluggish ice. Esker forming conduits were probably dominated by
supraglacially fed meltwater inputs. We also show that modelled subglacial drainage routes containing
the largest concentrations of meltwater show a close correlation with palaeo-ice stream locations. The
paucity of eskers along the terrestrial portion of these palaeo-ice streams and meltwater routes is
probably due to the prevalence of distributed drainage and the high erosion potential of fast-flowing
ice
Alternative Fourier Expansions for Inverse Square Law Forces
Few-body problems involving Coulomb or gravitational interactions between
pairs of particles, whether in classical or quantum physics, are generally
handled through a standard multipole expansion of the two-body potentials. We
discuss an alternative based on a compact, cylindrical Green's function
expansion that should have wide applicability throughout physics. Two-electron
"direct" and "exchange" integrals in many-electron quantum systems are
evaluated to illustrate the procedure which is more compact than the standard
one using Wigner coefficients and Slater integrals.Comment: 10 pages, latex/Revtex4, 1 figure
Markers of inflammation and cellular adhesion molecules in relation to insulin resistance in nondiabetic elderly: the Rotterdam study
Insulin resistance, which is highly prevalent in the elderly, is suggested
to be accompanied by an increased acute phase response. Until now, it is
unclear whether cellular adhesion molecules are involved in the clustering
of insulin resistance. In the present study, we examined the relationship
of insulin resistance (measured by postload insulin) with levels of
markers of inflammation and cellular adhesion molecules in a random sample
of 574 nondiabetic elderly men and women participating in the Rotterdam
Study. Associations were assessed by regression analysis, with ln-insulin
as the dependent variable [regression coefficient (95% confidence
interval)]. In our population, insulin was strongly and significantly (P <
0.001) associated with the markers of inflammation C-reactive protein
[1.52 (0.96-2.08)], alpha-1-antichymotrypsin [1.25 (0.82-1.69)], and IL-6
[2.60 (1.69-3.52)], adjusted for age and gender. Associations weakened, to
some extent, after additional adjustment for measures of obesity, smoking,
and cardiovascular disease. Insulin was associated with the soluble
intercellular adhesion molecule 1 [2.22 (1.29-3.16; P < 0.001)], whereas
no association with the soluble vascular cell adhesion molecule 1 was
found. The strength of the associations of insulin with C-reactive
protein, alpha-1-antichymotrypsin, IL-6, and soluble intercellular
adhesion molecule 1, as assessed by standardized regression coefficients,
was comparable with the strength of the associations of insulin with
high-density lipoprotein cholesterol, body mass index, and waist-to-hip
ratio. The results of this population-based study indicate that low-grade
inflammation and the cellular adhesion molecule soluble intercellular
adhesion molecule 1 are an integral part of insulin resistance in
nondiabetic elderly. These factors may contribute to the well-known
relationship between insulin resistance and cardiovascular disease risk
and might potentially become therapeutic targets in insulin resistant
subjects
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