9,963 research outputs found
Is the even distribution of insecticide-treated cattle essential for tsetse control? Modelling the impact of baits in heterogeneous environments
Background:
Eliminating Rhodesian sleeping sickness, the zoonotic form of Human African Trypanosomiasis, can be achieved only through interventions against the vectors, species of tsetse (Glossina). The use of insecticide-treated cattle is the most cost-effective method of controlling tsetse but its impact might be compromised by the patchy distribution of livestock. A deterministic simulation model was used to analyse the effects of spatial heterogeneities in habitat and baits (insecticide-treated cattle and targets) on the distribution and abundance of tsetse.
Methodology/Principal Findings:
The simulated area comprised an operational block extending 32 km from an area of good habitat from which tsetse might invade. Within the operational block, habitat comprised good areas mixed with poor ones where survival probabilities and population densities were lower. In good habitat, the natural daily mortalities of adults averaged 6.14% for males and 3.07% for females; the population grew 8.46in a year following a 90% reduction in densities of adults and pupae, but expired when the population density of males was reduced to <0.1/km2; daily movement of adults averaged 249 m for males and 367 m for females. Baits were placed throughout the operational area, or patchily to simulate uneven distributions of cattle and targets. Gaps of 2–3 km between baits were inconsequential provided the average imposed mortality per km2 across the entire operational area was maintained. Leaving gaps 5–7 km wide inside an area where baits killed 10% per day delayed effective control by 4–11 years. Corrective measures that put a few baits within the gaps were more effective than deploying extra baits on the edges.
Conclusions/Significance:
The uneven distribution of cattle within settled areas is unlikely to compromise the impact of insecticide-treated cattle on tsetse. However, where areas of >3 km wide are cattle-free then insecticide-treated targets should be deployed to compensate for the lack of cattle
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Insights into centriole geometry revealed by cryotomography of doublet and triplet centrioles.
Centrioles are cylindrical assemblies comprised of 9 singlet, doublet, or triplet microtubules, essential for the formation of motile and sensory cilia. While the structure of the cilium is being defined at increasing resolution, centriolar structure remains poorly understood. Here, we used electron cryo-tomography to determine the structure of mammalian (triplet) and Drosophila (doublet) centrioles. Mammalian centrioles have two distinct domains: a 200 nm proximal core region connected by A-C linkers, and a distal domain where the C-tubule is incomplete and a pair of novel linkages stabilize the assembly producing a geometry more closely resembling the ciliary axoneme. Drosophila centrioles resemble the mammalian core, but with their doublet microtubules linked through the A tubules. The commonality of core-region length, and the abrupt transition in mammalian centrioles, suggests a conserved length-setting mechanism. The unexpected linker diversity suggests how unique centriolar architectures arise in different tissues and organisms
Dynamics of myosin, microtubules, and Kinesin-6 at the cortex during cytokinesis in Drosophila S2 cells
© The Authors, 2009 . This article is distributed under the terms of the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License. The definitive version was published in Journal of Cell Biology 186 (2009): 727-738, doi:10.1083/jcb.200902083.Signals from the mitotic spindle during anaphase specify the location of the actomyosin contractile ring during cytokinesis, but the detailed mechanism remains unresolved. Here, we have imaged the dynamics of green fluorescent protein–tagged myosin filaments, microtubules, and Kinesin-6 (which carries activators of Rho guanosine triphosphatase) at the cell cortex using total internal reflection fluorescence microscopy in flattened Drosophila S2 cells. At anaphase onset, Kinesin-6 relocalizes to microtubule plus ends that grow toward the cortex, but refines its localization over time so that it concentrates on a subset of stable microtubules and along a diffuse cortical band at the equator. The pattern of Kinesin-6 localization closely resembles where new myosin filaments appear at the cortex by de novo assembly. While accumulating at the equator, myosin filaments disappear from the poles of the cell, a process that also requires Kinesin-6 as well as possibly other signals that emanate from the elongating spindle. These results suggest models for how Kinesin-6 might define the position of cortical myosin during cytokinesis.This work was supported by a National Institutes of Health grant NIH
38499 to R.D. Vale
Modalidades de pensamento em web design: contributo para a concepção de páginas web
RESUMO: O web design é uma área de intervenção do Design de
Comunicação onde existe a necessidade premente de se construir
modelos teóricos com a aplicabilidade de técnicas de estimulação da
criatividade de suporte à prática de projeto. Urge erradicar o
diletantismo e a confusão entre conceção e programação, a primeira,
claramente da competência de web designers, a segunda de
programadores. Atualmente, com as novas plataformas de gestão de
conteúdos os web designers conseguem desenvolver projetos criativos,
com usabilidade e com bastante autonomia ao nível da linguagem de
programação. Os designers web são também os designers de interface e
arquitetos de informação: não necessitam de fazer programação mas
têm de conhecer as potencialidades tecnológicas e de compreender os
utilizadores para desenvolver projeto. A criação de um site é uma tarefa
complexa e alguns aspetos essenciais podem passar despercebidos.
Atendendo ao exposto pretende-se apurar o que carateriza e distingue a
atividade do web designer como profissional e explorar a aplicabilidade
das técnicas de estimulação de criatividade operantes nas diferentes
modalidades de pensamento e que colaboram nesta área projetual. Assim
sendo, o objetivo deste artigo é evidenciar que o conhecimento de
diversas modalidades de pensamento e a aplicação de técnicas de
estimulação de criatividade são essenciais para obter resultados
estéticos, com um design de interface coerente, de fácil usabilidade. Para
o efeito, foram convocados vários registos disciplinares convergentes para
o contexto da presente investigação, nomeadamente a psicologia
cognitiva e as artes visuais. A revisão da literatura permitiu estabilizar
conceitos, planear inquéritos a empresas de web design que se
disnguem no mercado pela qualidade gráfica dos seus produtos e
desenvolver um projeto prático que justifica os beneficios da aplicação de
técnicas de estimulação de criatividade cooperantes nas diversas
modalidades de pensamento criativo como suporte à conceção de
páginas web. Este artigo tem com principal resultado que a aplicação de
técnicas de criatividade proporcionam resultados qualitativos
beneficiando a atividade projetual do web designer, através de um
modelo teórico.ABSTRACT: Web design is a Communication design intervention area in
which there is an urgent need to build theoretical models which are able
to apply creativity simulation techniques to support a specific project.
The dile_anism and misunderstanding between conception and
programming must be eradicated urgently. The first is clearly of the
competence of web designers and the la_er of programmers. Nowadays,
with the new contents management platiorms, web designers can
develop creative projects, which are both useful and autonomous
concerning programming language. Designers are also interface
designers and information architects: they don’t need to do programming
but they have to be aware of the technologic full potential and
understand the users in order to develop a project. The creation of a web
site is a complex task and there are some essential aspects that can go
unnoticed. According to what was previously mentioned, it is intended to
understand the applicability of the operating creativity simulation
techniques used in different modalities of thought which are involved in
this area. Therefore, the purpose of this investigation is to enhance that
the profound knowledge of both thought modalities and the application of
creativity stimulation techniques is essential to obtain aesthetic results,
with a coherent and highly usable interface design. In this regard, we
have collected several disciplinary records which converge to the context
of the current investigation, such as cognitive psychology and visual arts.
The revision of the literature allowed to establish concepts, plan surveys
to web design companies (which excel in the market for the graphic
quality of their products) and develop a practical project which su the
benefits of applying creativity stimulations techniques compliant in
the several creative thought modalities supporting the conception of web
pages. This paper has a main result the application of creativity
techniques leads to high quality results which benefit the project activity
of a web designer, thus being created a theoretical model.info:eu-repo/semantics/publishedVersio
Loop: the stupid things that adults do
Loop: The stupid things that adults do
The Thanet Loop is a bus route that circumnavigates Margate, Ramsgate and Broadstairs. This continuous service acts as a conveyer to the community, delivering children to school, patients to the hospital, commuters to their places of work and shoppers to town centres. In its own modest way ‘The Loop’ circulates life through Thanet, creating a pulse or a perpetual rhythm.
The project ‘Loop: the stupid things that adults do’ explores the idea of a circular journey with the intention of investigating repetition. In his book ‘Rhythmanalyisis,’ philosopher Henri Lefebvre identifies two types of repetition, circular and linear. Circular repetition develops from the cosmos and occurs naturally in days, seasons, tides and phases of the moon. While linear repetition is a social construct, imposed by structure, which can result in monotonous behaviour, such as daily commutes or routine visits to the dentist. These two patterns of repetition consistently and repeatedly effect and interfere with each other, creating patterns and sequences that are part of daily life. These cycles overlap and infuse, as individual patterns of behaviour briefly entwine within the enclosed space of the bus. Furthermore, in bringing together separate individuals or trajectories there cannot be any absolute repetition, as there will always be an interjection of difference or unforeseen circumstances.
The aim of each image is to record the duration of a full circuit of ‘The Loop’ in one single flat image. Repeating exactly the same journey on different days and at slightly varying times, the work explores the differentiation that can occur in replication. All the individual journeys, commutes and routines are collocated and re-presented into a distinct image for each loop. The resulting images have two titles; the first is a code that relates to the time of the trip, marking it out through a classification process. The second is produced from the conversations overheard on each particular journey.
Photography as a medium is fatally intersected by temporality; the camera reduces everything to a still frame, objectifying it through a process. Time and its complex rhythms are simplified, to a state where they are traces of what has passed. Photographs as images are removed from the continuous pressures of time, allowing the subject to be contemplated, examined and considered at leisure. In order to record the whole journey within a single image, the photographs are taken using a purpose made pinhole camera. Slowly absorbing the changes before the lens, each image becomes a representation of the journey and what passed before the camera on that specific excursion. Each unique image is characterised by the people using the bus, who punctuate the journey by choosing where the bus stops. These interruptions leave an imprint within the photographs produced. However, the main emphasis of each image is the light absorbed by the film, capturing the mood or atmosphere of that day. Thanet is renowned for the unique quality of light, which has attracted artists such as J.M.W. Turner to the area. This variation and luminosity of light comes into focus through the series and creates a unique collection of images
A comprehensive classification of galaxies in the SDSS: How to tell true from fake AGN?
We use the W_Ha versus [NII]/Ha (WHAN) diagram to provide a comprehensive
emission-line classification of SDSS galaxies. This classification is able to
cope with the large population of weak line galaxies that do not appear in
traditional diagrams due to a lack of some of the diagnostic lines. A further
advantage of the WHAN diagram is to allow the differentiation between two very
distinct classes that overlap in the LINER region of traditional diagnostic
diagrams. These are galaxies hosting a weakly active nucleus (wAGN) and
"retired galaxies" (RGs), i.e. galaxies that have stopped forming stars and are
ionized by their hot evolved low-mass stars. A useful criterion to distinguish
true from fake AGN (i.e. the RGs) is the ratio (\xi) of the
extinction-corrected L_Ha with respect to the Ha luminosity expected from
photoionization by stellar populations older than 100 Myr. This ratio follows a
markedly bimodal distribution, with a \xi >> 1 population composed by systems
undergoing star-formation and/or nuclear activity, and a peak at \xi ~ 1
corresponding to the prediction of the RG model. We base our classification
scheme on the equivalent width of Ha, an excellent observational proxy for \xi.
Based on the bimodal distribution of W_Ha, we set the division between wAGN and
RGs at W_Ha = 3 A. Five classes of galaxies are identified within the WHAN
diagram: (a) Pure star forming galaxies: log [NII]/Ha 3 A.
(b) Strong AGN (i.e., Seyferts): log [NII]/Ha > -0.4 and W_Ha > 6 A. (c) Weak
AGN: log [NII]/Ha > -0.4 and W_Ha between 3 and 6 A. (d) RGs: W_Ha < 3 A. (e)
Passive galaxies (actually, line-less galaxies): W_Ha and W_[NII] < 0.5 A. A
comparative analysis of star formation histories and of other properties in
these different classes of galaxies corroborates our proposed differentiation
between RGs and weak AGN in the LINER-like family. (Abridged)Comment: Accepted for publication in MNRA
Feeding Versus Feedback in NGC1068 probed with Gemini NIFS. I. Excitation
We present emission-line flux distributions and ratios for the inner 200pc of
the narrow-line region of the Seyfert2 galaxy NGC1068, using observations
obtained with the Gemini Near-infrared Integral Field Spectrograph (NIFS) in
the J, H and K bands at a spatial resolution of 10pc and spectral resolution of
5300. The molecular gas emission - traced by the K-band H_2 emission lines -
outlines an off-centered circumnuclear ring with a radius of 100pc showing
thermal excitation. The ionized gas emission lines show flux distributions
mostly outlining the previously known [OIII]5007 ionization bicone. But while
the flux distributions in the HI and HeII emission lines are very similar to
that observed in [OIII], the flux distribution in the [FeII] emission lines is
more extended and broader than a cone close to the nucleus, showing a "double
bowl" or `hourglass" structure". This difference is attributed to the fact that
the [FeII] emission, besides coming from the fully ionized region, comes also
from the more extended partially ionized regions, in gas excited mainly by
X-rays from the active galactic nucleus. A contribution to the [FeII] emission
from shocks along the bicone axis to NE and SW of the nucleus is also supported
by the enhancement of the [FeII](1.2570)/[PII](1.1885) and
[FeII](1.2570)/Pabeta emission-line ratios at these locations and is attributed
to the interaction of the radio jet with the NLR. The mass of ionized gas in
the inner 200pc of NGC1068 is MHII~2.2E4 M_Sun, while the mass of the H2
emitting gas is only M_{H2}~29M_Sun. Taking into account the dominant
contribution of the cold molecular gas, we obtain an estimate of the total
molecular gas mass of Mcold~2E7 M_Sun.Comment: accepeted for publication in MNRA
Management of erectile dysfunction post-radical prostatectomy
© 2015 Saleh et al.Radical prostatectomy is a commonly performed procedure for the treatment of localized prostate cancer. One of the long-term complications is erectile dysfunction. There is little consensus on the optimal management; however, it is agreed that treatment must be prompt to prevent fibrosis and increase oxygenation of penile tissue. It is vital that patient expectations are discussed, a realistic time frame of treatment provided, and treatment started as close to the prostatectomy as possible. Current treatment regimens rely on phosphodiesterase 5 inhibitors as a first-line therapy, with vacuum erection devices and intraurethral suppositories of alprostadil as possible treatment combination options. With nonresponders to these therapies, intracavernosal injections are resorted to. As a final measure, patients undergo the highly invasive penile prosthesis implantation. There is no uniform, objective treatment program for erectile dysfunction post-radical prostatectomy. Management plans are based on poorly conducted and often underpowered studies in combination with physician and patient preferences. They involve the aforementioned drugs and treatment methods in different sequences and doses. Prospective treatments include dietary supplements and gene therapy, which have shown promise with there proposed mechanisms of improving erectile function but are yet to be applied successfully in human patients
Biomarkers: a strategic tool in the assessment of environmental quality of coastal waters
Ecosystems are under the pressure of complex mixtures of contaminants whose effects are not always simple to assess. Biomarkers, acting as early warning signals of the presence of potentially toxic xenobiotics, are useful tools for assessing either exposure to, or the effects of these compounds providing information about the toxicant bioavailability. In fact, it has been argued that a full understanding of ecotoxicological processes must consider an integrated multi-level approach, in which molecular impact is related with higher-order biological consequences at the individual, population and community levels. Monitoring programs should make use of this tool to link contaminants and ecological responses fulfilling strategies like those launched by OSPAR (Commissions of Oslo and Paris) Convention on the protection of the marine environment of the North-East Atlantic and the International Council for the Exploration of the Sea (ICES). An overview of the work done in the past few years using biomarkers as in situ tools for pollution assessment in Portuguese coastal waters is presented as a contribution to the set up of a biomonitoring program for the Portuguese coastal zone. Considering the data set available the biomonitoring proposal should include the analysis of biomarkers and effects at individual levels. The aim of the program will include a spatial and temporal characterization of the biomarkers acetyl-cholinesterase, metallothioneins, DNA damage, adenylate energy charge and scope-for-growth levels. The investigation of the spatial variation of biomarkers is crucial to define sites for long term monitoring, which will be integrated with a chemical monitoring program. This framework will be a major contribution to the implementation of a national database for the use of biomarkers along the Portuguese coast.info:eu-repo/semantics/publishedVersio
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