2,549 research outputs found
Achieving high coverage of larval-stage mosquito surveillance: challenges for a community-based mosquito control programme in urban Dar es Salaam, Tanzania
Background: Preventing malaria by controlling mosquitoes in their larval stages requires regular sensitive monitoring of vector populations and intervention coverage. The study assessed the effectiveness of operational, community-based larval habitat surveillance systems within the Urban Malaria Control Programme (UMCP) in urban Dar es Salaam, Tanzania. Methods: Cross-sectional surveys were carried out to assess the ability of community-owned resource persons (CORPs) to detect mosquito breeding sites and larvae in areas with and without larviciding. Potential environmental and programmatic determinants of habitat detection coverage and detection sensitivity of mosquito larvae were recorded during guided walks with 64 different CORPs to assess the accuracy of data each had collected the previous day. Results: CORPs reported the presence of 66.2% of all aquatic habitats (1,963/2,965), but only detected Anopheles larvae in 12.6% (29/230) of habitats that contained them. Detection sensitivity was particularly low for late-stage Anopheles (2.7%, 3/111), the most direct programmatic indicator of malaria vector productivity. Whether a CORP found a wet habitat or not was associated with his/her unfamiliarity with the area (Odds Ratio (OR) [95% confidence interval (CI)] = 0.16 [0.130, 0.203], P < 0.001), the habitat type (P < 0.001) or a fence around the compound (OR [95% CI] = 0.50 [0.386, 0.646], P < 0.001). The majority of mosquito larvae (Anophelines 57.8% (133/230) and Culicines 55.9% (461/825) were not reported because their habitats were not found. The only factor affecting detection of Anopheline larvae in habitats that were reported by CORPs was larviciding, which reduced sensitivity (OR [95% CI] = 0.37 [0.142, 0.965], P = 0.042). Conclusions: Accessibility of habitats in urban settings presents a major challenge because the majority of compounds are fenced for security reasons. Furthermore, CORPs under-reported larvae especially where larvicides were applied. This UMCP system for larval surveillance in cities must be urgently revised to improve access to enclosed compounds and the sensitivity with which habitats are searched for larvae
Environment-Driven Shifts in Inter-Individual Variation and Phenotypic Integration within Subnetworks of the Mussel Transcriptome and Proteome
The environment can alter the magnitude of phenotypic variation among individuals, potentially influencing evolutionary trajectories. However, environmental influences on variation are complex and remain understudied. Populations in heterogeneous environments might exhibit more variation, the amount of variation could differ between benign and stressful conditions, and/or variation might manifest in different ways among stages of the gene-to-protein expression cascade or among physiological functions. Here, we explore these three issues by quantifying patterns of inter-individual variation in both transcript and protein expression levels among California mussels, Mytilus californianus Conrad. Mussels were exposed to five ecologically relevant treatments that varied in the mean and inter-individual heterogeneity of body temperature. To target a diverse set of physiological functions, we assessed variation within 19 expression subnetworks, including canonical stress-response pathways and empirically derived co-expression clusters that represent a diffuse set of cellular processes. Variation in expression was particularly pronounced in the treatments with high mean and heterogeneous body temperatures. However, with few exceptions, environment-dependent shifts of variation in the transcriptome were not reflected in the proteome. A metric of phenotypic integration provided evidence for a greater degree of constraint on relative expression levels (i.e., stronger correlation) within expression subnetworks in benign, homogeneous environments. Our results suggest that environments that are more stressful on average – and which also tend to be more heterogeneous – can relax these expression constraints and reduce phenotypic integration within biochemical subnetworks. Context-dependent \u27unmasking\u27 of functional variation may contribute to inter-individual differences in physiological phenotype and performance in stressful environments
Implementation of higher-order absorbing boundary conditions for the Einstein equations
We present an implementation of absorbing boundary conditions for the
Einstein equations based on the recent work of Buchman and Sarbach. In this
paper, we assume that spacetime may be linearized about Minkowski space close
to the outer boundary, which is taken to be a coordinate sphere. We reformulate
the boundary conditions as conditions on the gauge-invariant
Regge-Wheeler-Zerilli scalars. Higher-order radial derivatives are eliminated
by rewriting the boundary conditions as a system of ODEs for a set of auxiliary
variables intrinsic to the boundary. From these we construct boundary data for
a set of well-posed constraint-preserving boundary conditions for the Einstein
equations in a first-order generalized harmonic formulation. This construction
has direct applications to outer boundary conditions in simulations of isolated
systems (e.g., binary black holes) as well as to the problem of
Cauchy-perturbative matching. As a test problem for our numerical
implementation, we consider linearized multipolar gravitational waves in TT
gauge, with angular momentum numbers l=2 (Teukolsky waves), 3 and 4. We
demonstrate that the perfectly absorbing boundary condition B_L of order L=l
yields no spurious reflections to linear order in perturbation theory. This is
in contrast to the lower-order absorbing boundary conditions B_L with L<l,
which include the widely used freezing-Psi_0 boundary condition that imposes
the vanishing of the Newman-Penrose scalar Psi_0.Comment: 25 pages, 9 figures. Minor clarifications. Final version to appear in
Class. Quantum Grav
DATASET2050 D3.2 - Future Passenger Demand Profile
The FlightPath 2050 goal of enabling 90 per cent of European passengers to complete their door-to-door journey within four hours is a very challenging task. A major objective of the DATASET2050 project is to deliver insight into both current and future processes relating to the European transport system in this context.
The deliverable D3.2 "Future Passenger Demand Profile" focuses on the future demand side of European (air) transport. Namely, the first goal is to develop a range of passenger profiles for the year 2035 and to provide implications for passenger profiles for 2050. For this purpose, the development of passenger characteristics - including demographic, geographic, socio-economic and behavioural aspects as well as particular mobility patterns - is analysed using available European data and forecasts.
Based on this analysis, on specific mobility behaviour of the different member states (EU28 and EFTA countries) as well as on a high-level-factor identification, six different passenger profiles for 2035 are developed. These six profiles differ by main travel purpose (private, business and leisure, which is the combination of business and leisure trips), predominant age group, income level (low, medium, high) and several other characteristics. Furthermore, a demand model is applied showing the high relevance of gross domestic product (GDP) and education for a steady growth of passenger traffic volume in the EU28 and EFTA countries until 2050.
The outcomes of the current deliverable will be put in contrast with those coming from D4.2 (Future supply profile), enabling thus a comprehensive assessment on the European door-to-door mobility in the future. Specifically, the deliverable results will be used in D5.1 (Mobility assessment), D5.2 (Assessment execution) and D5.3 (Novel concept foundations for European mobility)
The enigma of GCIRS 3 - Constraining the properties of the mid-infrared reference star of the central parsec of the Milky Way with optical long baseline interferometry
GCIRS3 is the most prominent MIR source in the central pc of the Galaxy. NIR
spectroscopy failed to solve the enigma of its nature. The properties of
extreme individual objects of the central stellar cluster contribute to our
knowledge of star and dust formation close to a supermassive black hole. We
initiated an interferometric experiment to understand IRS3 and investigate its
properties as spectroscopic and interferometric reference star at 10um. VISIR
imaging separates a compact source from diffuse, surrounding emission. The
VLTI/MIDI instrument was used to measure visibilities at 10mas resolution of
that compact 10um source, still unresolved by a single VLT. Photometry data
were added to enable simple SED- and full radiative transfer-models of the
data. The luminosity and size estimates show that IRS3 is probably a cool
carbon star enshrouded by a complex dust distribution. Dust temperatures were
derived. The coinciding interpretation of multiple datasets confirm dust
emission at several spatial scales. The IF data resolve the innermost area of
dust formation. Despite observed deep silicate absorption towards IRS3 we favor
a carbon rich chemistry of the circumstellar dust shell. The silicate
absorption most probably takes place in the outer diffuse dust, which is mostly
ignored by MIDI measurements. This indicates physically and chemically distinct
conditions of the local dust, changing with the distance to IRS3. We have
demonstrated that optical long baseline interferometry at infrared wavelengths
is an indispensable tool to investigate sources at the Galactic Center. Our
findings suggest further studies of the composition of interstellar dust and
the shape of the 10um silicate feature at this outstanding region.Comment: accepted by A&A, now in press; 19 pages, 22 figures, 5 table
Multi-omics Reveals Largely Distinct Transcript- and Protein-Level Responses to the Environment in an Intertidal Mussel
Organismal responses to stressful environments are influenced by numerous transcript- and protein-level mechanisms, and the relationships between expression changes at these levels are not always straightforward. Here, we used paired transcriptomic and proteomic datasets from two previous studies from gill of the California mussel, Mytilus californianus, to explore how simultaneous transcript and protein abundance patterns may diverge under different environmental scenarios. Field-acclimatized mussels were sampled from two disparate intertidal sites; individuals from one site were subjected to three further treatments (common garden, low-intertidal or high-intertidal outplant) that vary in temperature and feeding time. Assessing 1519 genes shared between the two datasets revealed that both transcript and protein expression patterns differentiated the treatments at a global level, despite numerous underlying discrepancies. There were far more instances of differential expression between treatments in transcript only (1451) or protein only (226) than of the two levels shifting expression concordantly (68 instances). Upregulated expression of cilium-associated transcripts (likely related to feeding) was associated with relatively benign field treatments. In the most stressful treatment, transcripts, but not proteins, for several molecular chaperones (including heat shock proteins and endoplasmic reticulum chaperones) were more abundant, consistent with a threshold model for induction of translation of constitutively available mRNAs. Overall, these results suggest that the relative importance of transcript- and protein-level regulation (translation and/or turnover) differs among cellular functions and across specific microhabitats or environmental contexts. Furthermore, the degree of concordance between transcript and protein expression can vary across benign versus acutely stressful environmental conditions
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The Beagle 2 optical microscope
Introduction to the Beagle2 optical microscope
A comparative investigation of thickness measurements of ultra-thin water films by scanning probe techniques
The reliable operation of micro and nanomechanical devices necessitates a
thorough knowledge of the water film thickness present on the surfaces of these
devices with an accuracy in the nm range. In this work, the thickness of an
ultra-thin water layer was measured by distance tunnelling spectroscopy and
distance dynamic force spectroscopy during desorption in an ultra-high vacuum
system, from about 2.5 nm up to complete desorption at 1E-8 mbar. The
tunnelling current as well as the amplitude of vibration and the normal force
were detected as a function of the probe-sample distance. In these experiments,
a direct conversion of the results of both methods is possible. From the
standpoint of surface science, taking the state-of-the-art concerning
adsorbates on surfaces into consideration, dynamic force spectroscopy provides
the most accurate values. The previously reported tunnelling spectroscopy,
requiring the application of significantly high voltages, generally leads to
values that are 25 times higher than values determined by dynamic force
spectroscopy
NACO/SAM observations of sources at the Galactic Center
Sparse aperture masking (SAM) interferometry combined with Adaptive Optics
(AO) is a technique that is uniquely suited to investigate structures near the
diffraction limit of large telescopes. The strengths of the technique are a
robust calibration of the Point Spread Function (PSF) while maintaining a
relatively high dynamic range. We used SAM+AO observations to investigate the
circumstellar environment of several bright sources with infrared excess in the
central parsec of the Galaxy. For our observations, unstable atmospheric
conditions as well as significant residuals after the background subtraction
presented serious problems for the standard approach of calibrating SAM data
via interspersed observations of reference stars. We circumvented these
difficulties by constructing a synthesized calibrator directly from sources
within the field-of-view. When observing crowded fields, this novel method can
boost the efficiency of SAM observations because it renders interspersed
calibrator observations unnecessary. Here, we presented the first NaCo/SAM
images reconstructed using this method.Comment: 8 pages, 10 figures, proceedings of the conference "Astrophysics at
High Angular Resolution" (AHAR-2011
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The Beagle 2 microscope
The Beagle 2 microscope provides optical images of the Martian surface at a resolution 5x higher than any other experiment currently planned. By using a novel illumination system it images in three colors and can also detect fluorescent materials
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