1,006 research outputs found
Chasing Flies: The use of wingbeat frequency as a communication cue in Calyptrate Flies (Diptera: Calyptratae)
The incidental sound produced by the oscillation of insect wings during flight provides an opportunity for species identification. Calyptrate flies include some of the fastest and most agile flying insects, capable of rapid changes in direction and the fast pursuit of conspecifics. This flight pattern makes the continuous and close recording of their wingbeat frequency difficult and limited to confined specimens. Advances in sound editor and analysis software, however, have made it possible to isolate low amplitude sounds using noise reduction and pitch detection algorithms. To explore differences in wingbeat frequency between genera and sex, 40 specimens of three-day old Sarcophaga crassipalpis, Lucilia sericata, Calliphora dubia, and Musca vetustissima were individually recorded in free flight in a temperature-controlled room. Results showed significant differences in wingbeat frequency between the four species and intersexual differences for each species. Discriminant analysis classifying the three carrion flies resulted in 77.5% classified correctly overall, with the correct classification of 82.5% of S. crassipalpis, 60% of C. dubia, and 90% of L. sericata, when both mean wingbeat frequency and sex were included. Intersexual differences were further demonstrated by male flies showing significantly higher variability than females in three of the species. These observed intergeneric and intersexual differences in wingbeat frequency start the discussion on the use of the metric as a communication signal by this taxon. The success of the methodology demonstrated differences at the genus level and encourages the recording of additional species and the use of wingbeat frequency as an identification tool for these flies
Crescimento e produção da cultura de batata primor na região do Oeste. II) Validação de campo do modelo POTATO.2
Parte IIinfo:eu-repo/semantics/publishedVersio
Aplicação de um modelo de simulação do desenvolvimento da batateira à cultura da batata primor na região do Oeste
Apresenta-se um modelo de simulação do desenvolvimento da batateira
aplicado ao caso particular da batata-primor na região do Oeste. Comparam-se os
resultados do modelo com observações de campo efectuadas no concelho da Lourinhã,
no ano de 1987, para a variedade Spunta em três densidades de plantação. Finalmente
apresentam-se as potencialidades de utilização do modeloinfo:eu-repo/semantics/publishedVersio
Crescimento e produção da cultura de batata primor na região Oeste. I) Análise comparativa do crescimento e produção em três densidades de população
Parte Iinfo:eu-repo/semantics/publishedVersio
Estimation de la surface foliaire principale et secondaire d’un sarment de vigne
Dans ce travail on présente des modèles empiriques pour estimer, de façon directe et non destructive, la
surface foliaire principale et secondaire d’un sarment de vigne pour quatre cépages portugaises. La surface
d’une feuille a été estimée avec un modèle basé sur la forte corrélation entre la somme des longueurs des
deux premières nervures latérales et la surface foliaire. Pour l’estimative de la surface foliaire principale
d’un sarment on a développé un modèle a partir d’une régression multiple de quatre variables explicatives:
longueur du sarment, nombre de feuilles principales et surface foliaire de la feuille majeure et mineure.
Pour la surface foliaire secondaire on propose un modèle similaire mais en considérant chaque entrecoeur
comme une feuille composé. Ce modèle utilise comme variables explicatives le nombre de feuilles
secondaires, le nombre d’entrecoeurs et la surface foliaire et nombre de feuilles de l‘entrecoeur major et
minore. La surface foliaire de chacun de ces deux entrecoeurs est estimé avec un modèle similaire a celui
proposé pour les feuilles principales mais sans la longueur du rameau. Ces modèles ont été validés avec
des données indépendants d’un échantillon de sarments prélevés périodiquement dans la saison. D’après
les bons résultats de la validation on peut dire que, avec ces modèles, on peut estimer rapidement la
surface foliaire total d’un sarment, de façon non destructive et avec une bonne précisioninfo:eu-repo/semantics/publishedVersio
Advanced Compton Telescope Designs and SN Science
The Advanced Compton Telescope (ACT) has been suggested to be the optimal
next-generation instrument to study nuclear gamma-ray lines. In this work, we
investigate the potential of three hypothetical designs of the ACT to perform
SN science. We provide estimates of 1) the SN detection rate, 2) the SN Ia
discrimination rate, and 3) which gamma-ray lines would be detected from
specific supernova remnants. We find that the prompt emission from a SN Ia is
such that it is unlikely that one would be within the range that an
INTERMEDIATE ACT would be able to distinguish between explosion scenarios,
although such an instrument would detect a handful of SNRs.
We further find that the SUPERIOR ACT design would be a truly breakthrough
instrument for SN science. By supplying these estimates, we intend to assist
the gamma-ray astrophysics community in deciding the course of the next decade
of gamma-ray SN science.Comment: 10 pages, accepted for publication in New astronomy Reviews
(Astronomy with Radioactivities III
Outer Regions of the Milky Way
With the start of the Gaia era, the time has come to address the major
challenge of deriving the star formation history and evolution of the disk of
our MilkyWay. Here we review our present knowledge of the outer regions of the
Milky Way disk population. Its stellar content, its structure and its dynamical
and chemical evolution are summarized, focussing on our lack of understanding
both from an observational and a theoretical viewpoint. We describe the
unprecedented data that Gaia and the upcoming ground-based spectroscopic
surveys will provide in the next decade. More in detail, we quantify the expect
accuracy in position, velocity and astrophysical parameters of some of the key
tracers of the stellar populations in the outer Galactic disk. Some insights on
the future capability of these surveys to answer crucial and fundamental issues
are discussed, such as the mechanisms driving the spiral arms and the warp
formation. Our Galaxy, theMilkyWay, is our cosmological laboratory for
understanding the process of formation and evolution of disk galaxies. What we
learn in the next decades will be naturally transferred to the extragalactic
domain.Comment: 22 pages, 10 figures, Invited review, Book chapter in "Outskirts of
Galaxies", Eds. J. H. Knapen, J. C. Lee and A. Gil de Paz, Astrophysics and
Space Science Library, Springer, in pres
Artemisinin inhibits neutrophil and macrophage chemotaxis, cytokine production and NET release
Immune cell chemotaxis to the sites of pathogen invasion is critical for fighting infection, but in life-threatening conditions such as sepsis and Covid-19, excess activation of the innate immune system is thought to cause a damaging invasion of immune cells into tissues and a consequent excessive release of cytokines, chemokines and neutrophil extracellular traps (NETs). In these circumstances, tempering excessive activation of the innate immune system may, paradoxically, promote recovery. Here we identify the antimalarial compound artemisinin as a potent and selective inhibitor of neutrophil and macrophage chemotaxis induced by a range of chemotactic agents. Artemisinin released calcium from intracellular stores in a similar way to thapsigargin, a known inhibitor of the Sarco/Endoplasmic Reticulum Calcium ATPase pump (SERCA), but unlike thapsigargin, artemisinin blocks only the SERCA3 isoform. Inhibition of SERCA3 by artemisinin was irreversible and was inhibited by iron chelation, suggesting iron-catalysed alkylation of a specific cysteine residue in SERCA3 as the mechanism by which artemisinin inhibits neutrophil motility. In murine infection models, artemisinin potently suppressed neutrophil invasion into both peritoneum and lung in vivo and inhibited the release of cytokines/chemokines and NETs. This work suggests that artemisinin may have value as a therapy in conditions such as sepsis and Covid-19 in which over-activation of the innate immune system causes tissue injury that can lead to death
Quantum radiation pressure on a moving mirror at finite temperature
We compute the radiation pressure force on a moving mirror, in the
nonrelativistic approximation, assuming the field to be at temperature At
high temperature, the force has a dissipative component proportional to the
mirror velocity, which results from Doppler shift of the reflected thermal
photons. In the case of a scalar field, the force has also a dispersive
component associated to a mass correction. In the electromagnetic case, the
separate contributions to the mass correction from the two polarizations
cancel. We also derive explicit results in the low temperature regime, and
present numerical results for the general case. As an application, we compute
the dissipation and decoherence rates for a mirror in a harmonic potential
well.Comment: Figure 3 replaced, changes mainly in Sections IV and V, new appendix
introduced. To appear in Physical Review
SIAMVITI – Viticultura portuguesa num cenário de alterações climáticas: Impactos e medidas de adaptação
info:eu-repo/semantics/publishedVersio
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