2,065 research outputs found
Is diapause an ancient adaptation in Drosophila?
D. melanogaster enters a state of reproductive arrest when exposed to low temperatures (12 °C) and shorter photoperiods. A number of studies have suggested that diapause has recently evolved in European D. melanogaster populations, that it is not present in the sibling species D. simulans, that it is non-photoperiodic in American D. melanogaster populations, and that it spontaneously terminates after 6â8 weeks. We have studied the overwintering phenotype under different conditions and observe that American, European and, surprisingly, African D. melanogaster populations can show photoperiodic diapause, as can European, but not African D. simulans. Surprisingly other Drosophila species from pan-tropical regions can also show significant levels of photoperiodic diapause. We observe that spontaneous termination of diapause after a few weeks can be largely avoided with a more realistic winter simulation for D. melanogaster, but not D. simulans. Examining metabolite accumulation during diapause reveals that the shallow diapause of D. melanogaster has similar features to that of other more robustly-diapausing species. Our results suggest that diapause may be an ancient character that emerged in the tropics to resist unfavourable seasonal conditions and which has been enhanced during D. melanogasterâs colonisation of temperate regions. Our results also highlight how different methodologies to quantify diapause can lead to apparently conflicting results that we believe can now largely be resolved
Do we understand the unquenched value of fB?
I review our qualitative understanding of the increase in the value of the B
meson decay constant (fB), when dynamical fermions are included in lattice QCD
calculations.Comment: 4 pages. Talk at UK Phenomenology Workshop on Heavy Flavour and CP
Violation, Durham, 17 - 22 September 2000 (Minor typo fixed
Use of Non-Steroidal Anti-Inflammatory Drugs That Elevate Cardiovascular Risk: An Examination of Sales and Essential Medicines Lists in Low-, Middle-, and High-Income Countries
PMCID: PMC3570554This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Exploring the components, asymmetry and distribution of relationship quality in wild Barbary macaques (Macaca sylvanus)
Social relationships between group members are a key feature of many animal societies. The quality of social relationships has been described by three main components: value, compatibility and security, based on the benefits, tenure and stability of social exchanges. We aimed to analyse whether this three component structure could be used to describe the quality of social relationships in wild Barbary macaques (Macaca sylvanus). Moreover, we examined whether relationship quality was affected by the sex, age and rank differences between social partners, and investigated the asymmetric nature of social relationships. We collected over 1,900 hours of focal data on seven behavioural variables measuring relationship quality,
and used principal component analysis to investigate how these variables clustered together. We found that relationship quality in wild Barbary macaques can be described by a three component structure that represents the value, compatibility and security of a relationship. Female-female dyads had more valuable relationships and same-age dyads more compatible relationships than any other dyad. Rank difference had no effect on the quality of a social relationship. Finally, we found a high degree of asymmetry in how members of a dyad exchange social behaviour. We argue that the asymmetry of social
relationships should be taken into account when exploring the pattern and function of social behaviour in animal societies
Clinical decision support using Open Data
First Online: 18 May 2020.The growth of Electronical Health Records (EHR) in healthcare has been gradual. However, a simple EHR system has become inefficient in supporting health professionals on decision making. In this sense, the need to acquire knowledge from storing data using open models and techniques has emerged, for the sake of improving the quality of service provided and to support the decision-making process. The usage of open models promotes interoperability between systems, communicating more efficiently. In this sense, the OpenEHR open data approach is applied, modelling data in two levels to distinguish knowledge from information. The application of clinical terminologies was fundamental in this study, in order to control data semantics based on coded clinical terms. This article culminated from the conceptualization of the knowledge acquisition process to represent Clinical Decision Support, using open data models.The work has been supported by FCTâFundação para a CiĂȘncia e Tec-nologia within the Project Scope UID/CEC/00319/2019 and DSAIPA/DS/0084/2018
Feeding spectra and activity of the freshwater crab Trichodactylus kensleyi (Decapoda: Brachyura: Trichodactylidae) at La Plata basin
Background: In inland water systems, it is important to characterize the trophic links in order to identify the âtrophic speciesâ and, from the studies of functional diversity, understand the dynamics of matter and energy in these environments. The aim of this study is to analyze the natural diet of Trichodactylus kensleyi of subtropical rainforest streams and corroborate the temporal variation in the trophic activity during day hours.
Results: A total of 15 major taxonomic groups were recognized in gut contents. The index of relative importance identified the following main prey items in decreasing order of importance: vegetal remains, oligochaetes, chironomid larvae, and algae. A significant difference was found in the amount of full stomachs during day hours showing a less trophic activity at midday and afternoon. The index of relative importance values evidenced the consumption of different prey according to day moments. Results of the gut content indicate that T. kensleyi is an omnivorous crab like other trichodactylid species. Opportunistic behavior is revealed by the ingestion of organisms abundant in streams such as oligochaetes and chironomid larvae. The consumption of allochthonous plant debris shows the importance of this crab as shredder in subtropical streams. However, the effective assimilation of plant matter is yet unknown in trichodactylid crabs.
Conclusions: This research provides knowledge that complements previous studies about trophic relationships of trichodactylid crabs and supported the importance of T. kensleyi in the transference of energy and matter from benthic community and riparian sources to superior trophic levels using both macro- and microfauna.Fil: Williner, VerĂłnica. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Santa Fe. Instituto Nacional de LimnologĂa. Universidad Nacional del Litoral. Instituto Nacional de LimnologĂa; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; ArgentinaFil: de Azevedo Carvalho, Debora. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Santa Fe. Instituto Nacional de LimnologĂa. Universidad Nacional del Litoral. Instituto Nacional de LimnologĂa; ArgentinaFil: Collins, Pablo Agustin. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Santa Fe. Instituto Nacional de LimnologĂa. Universidad Nacional del Litoral. Instituto Nacional de LimnologĂa; Argentina. Universidad Nacional del Litoral. Facultad de BioquĂmica y Ciencias BiolĂłgicas; Argentin
Theoretical Aspects of Particle Production
These lectures describe some of the latest data on particle production in
high-energy collisions and compare them with theoretical calculations and
models based on QCD. The main topics covered are: fragmentation functions and
factorization, small-x fragmentation, hadronization models, differences between
quark and gluon fragmentation, current and target fragmentation in deep
inelastic scattering, and heavy quark fragmentation.Comment: 26 pages, 27 figures. Lectures at International Summer School on
Particle Production Spanning MeV and TeV Energies, Nijmegen, The Netherlands,
August 199
Quenched charmonium spectrum
We study charmonium using the standard relativistic formalism in the quenched
approximation, on a set of lattices with isotropic lattice spacings ranging
from 0.1 to 0.04 fm. We concentrate on the calculation of the hyperfine
splitting between eta_c and J/psi, aiming for a controlled continuum
extrapolation of this quantity. The splitting extracted from the
non-perturbatively improved clover Dirac operator shows very little dependence
on the lattice spacing for fm. The dependence is much stronger for
Wilson and tree-level improved clover operators, but they still yield
consistent extrapolations if sufficiently fine lattices, fm (), are used. Our result for the hyperfine splitting is
77(2)(6) MeV (where Sommer's parameter, r_0, is used to fix the scale). This
value remains about 30% below experiment. Dynamical fermions and OZI-forbidden
diagrams both contribute to the remainder. Results for the eta_c and J/psi wave
functions are also presented.Comment: 22 pages, 7 figure
Quantum Gravity in Everyday Life: General Relativity as an Effective Field Theory
This article is meant as a summary and introduction to the ideas of effective
field theory as applied to gravitational systems.
Contents:
1. Introduction
2. Effective Field Theories
3. Low-Energy Quantum Gravity
4. Explicit Quantum Calculations
5. ConclusionsComment: 56 pages, 2 figures, JHEP style, Invited review to appear in Living
Reviews of Relativit
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