1,218 research outputs found
Biology of Diachasmimorpha longicaudata, A Parasitoid of Carambola Fruit Fly, (Diptera; Tephritidae)
The life cycle study of Diachasmimorpha longicaudata, a larval parasitoid of Bactrocera (B) sp. near
Bactrocera dorsalis A, was conducted in the laboratory (26°C± 1.5°). There were 4 larval stages based on the size
of the mouthhook. The first larval moult occurred in the newly formed pupanum of the host. The entire developmental
periods for males and females were 16.3 ± 0.8 day and 17.5 ± 0.8 days, respectively. The average reproductive
capacity per female during the life-span was 92 ± 4.5 eggs
ANALYSIS OF MULTICHANNEL SIGNALS USING A CHANNEL SIMULATOR
poster abstractsIn biological systems ion channels can be thought of as opening and clos-ing pores that allow the flow of ion through a membrane. Ion channels are responsible for intracellular communication and keeping an osmotic equilib-rium across cell membranes. Measurements of ion channel activities that generate multichannel events (the opening of more than one channel at a time) are important to understand, but difficult to analyze. In many cases the multichannel events are discarded instead of used in the analysis. The availability of a channel signal simulator offers an excellent opportunity to develop and test statistical models for analysis of multichannel signals. We have generated single channel traces for various open probabilities and then digitally superimposed these signals to obtain multichannel events. We then applied our simplified analysis to these multichannel traces to calculate sin-gle channel parameters such as the average ON and OFF times and their statistical distribution of the ON times. The average ON time as well as the ON time distribution matched the single channel input mean open time. The importance of our findings is that our proposed analysis will be able to use the statistical distribution of ON times, in addition to the traditional “dwell time” (or average ON time) parameter, to characterize ion channels
Effect of Age at Weaning on the Physiological Stress Response and Temperament of Two Beef Cattle Breeds
The study was conducted to evaluate the effect of age at weaning and breed on the stress response of calves to weaning and their temperament. At calving, 14 Parda de Montaña calves and 14 Pirenaica calves were randomly assigned to either early weaning (at 90 days) or traditional weaning (at 150 days) treatment. During nursing, calves were allowed to suckle their dams twice a day for 30 min. After weaning, calves were placed in an adjacent barn without access to their dams, where they remained for 7 days. On day 8 after weaning, they were transported to a feedlot where they received an intensive diet. Blood samples were taken 168 h before weaning (baseline) and 6, 24, 48 and 168 h after weaning for cortisol, fibrinogen and haematology analyses, and temperament was measured 90 and 180 days after weaning with the flight speed test. Cortisol concentration increased after weaning, irrespective of age at weaning. Early-weaned calves had a lower fibrinogen baseline and a greater increase in fibrinogen concentrations 48 h after weaning than traditionally weaned calves. Moreover, fibrinogen concentration returned to baseline values 168 h after weaning in traditionally weaned calves, whereas it remained high in early-weaned calves. Concerning breed effects, Pirenaica calves had higher cortisol concentration and fibrinogen increments after weaning than Parda de Montaña calves. Slight alterations occurred after weaning in haematology, but all parameters returned to baseline values 168 h after weaning, with no significant effects of age at weaning or breed. Despite the absence of clinical signs, early-weaned calves of both breeds suffered marginal anaemia, according to haemoglobin values. Regardless of age at weaning, Pirenaica calves had greater reactivity to human presence than Parda de Montaña calves, according to their higher flight speed values measured. Finally, early-weaned calves were lighter than traditionally weaned calves at weaning, but had similar weight gains in the feedlot. Consequently, they needed an additional 40 days to reach the target weight, irrespective of breed. Therefore, age at weaning had no major effects on the stress response to weaning or temperament, but early weaning increased the length of the feedlot period. On the other hand, Pirenaica calves were more reactive than Parda de Montaña calves to the stress of weaning and human presence
Reversible Graphene decoupling by NaCl photo-dissociation
We describe the reversible intercalation of Na under graphene on Ir(111) by
photo-dissociation of a previously adsorbed NaCl overlayer. After room
temperature evaporation, NaCl adsorbs on top of graphene forming a bilayer.
With a combination of electron diffraction and photoemission techniques we
demonstrate that the NaCl overlayer dissociates upon a short exposure to an
X-ray beam. As a result, chlorine desorbs while sodium intercalates under the
graphene, inducing an electronic decoupling from the underlying metal. Low
energy electron diffraction shows the disappearance of the moir\'e pattern when
Na intercalates between graphene and iridium. Analysis of the Na 2p core-level
by X-ray photoelectron spectroscopy shows a chemical change from NaCl to
metallic buried Na at the graphene/Ir interface. The intercalation-decoupling
process leads to a n-doped graphene due to the charge transfer from the Na, as
revealed by constant energy angle resolved X-ray photoemission maps. Moreover,
the process is reversible by a mild annealing of the samples without damaging
the graphene
The Life-cycle of biosteres persulcatus with reference to adults' reproductive capacity on eggs of Carambola fruit-fly
A study of the life-cycle of Biosteres persulcatus Silvestri, a larval parasitoid of (Bactrocera (B) sp. near
Bactrocera dorsalis A), was conducted in the laboratory (26.50C± 1.50 C). There are 4 larval stages as indicated
by the sizes of the mouthhooks. The first larval moult occurred in the newly{ormed puparium of the host. The
entire developmental period from egg to adult emergence for male and female was 16.3± 0.80 days and 1 7.1 ± 0.80
days respectively. The average reproductive capacity during the life span was 67 ± 3.5 eggs
A model for high-mass microquasar jets under the influence of a strong stellar wind
Context. High-mass microquasars (HMMQs) are systems from which relativistic jets are launched. At the scales of several times the binary system size, the jets are expected to follow a helical path caused by the interaction with a strong stellar wind and orbital motion.Such a trajectory has its influence on the non-thermal emission of the jets, which also depends strongly on the observing angle due to Doppler boosting effects. Aims. We explore how the expected non-thermal emission of HMMQ jets at small scales is affected by the impact of the stellar wind and the orbital motion on the jet propagation. Methods. We studied the broadband non-thermal emission, from radio to gamma rays, produced in HMMQ jets up to a distance of several orbital separations, taking into account a realistic jet trajectory, different model parameters, and orbital modulation. The jet trajectory is computed by considering momentum transfer with the stellar wind. Electrons are injected at the position where a recollimation shock in the jets is expected due to the wind impact. Their distribution along the jet path is obtained assuming local acceleration at the recollimation shock, and cooling via adiabatic, synchrotron, and inverse Compton processes. The synchrotron and inverse Compton emission is calculated taking into account synchrotron self-absorption within the jet, free-free absorption with the stellar wind, and absorption by stellar photons via pair production. Results. The spectrum is totally dominated by the jet over the counter-jet due to Doppler boosting. Broadband emission from microwaves to gamma rays is predicted, with radio emission being totally absorbed. This emission is rather concentrated in the regions close to the binary system and features strong orbital modulation at high energies. Asymmetric light curves are obtained owing to the helical trajectory of the jets. Conclusions. The presence of helical shaped jets could be inferred from asymmetries in the light curves, which become noticeable only for large jet Lorentz factors and low magnetic fields. Model parameters could be constrained if accurate phase-resolved lightcurves from GeV to TeV energies were available. The predictions for the synchrotron and the inverse Compton radiation are quite sensitive of the parameters determining the wind-jet interaction structure
Gamma rays from jets interacting with BLR clouds in blazars
Context. The innermost parts of powerful jets in active galactic nuclei are surrounded by dense, high-velocity clouds from the broad-line region, which may penetrate into the jet and lead to the formation of a strong shock. Such jet-cloud interactions are expected to have measurable effects on the γ-ray emission from blazars. Aims. We characterise the dynamics of a typical cloud-jet interaction scenario, and the evolution of its radiative output in the 0.1-30 GeV energy range, to assess to what extent these interactions can contribute to the γ-ray emission in blazars. Methods. We use semi-analytical descriptions of the jet-cloud dynamics, taking into account the expansion of the cloud inside the jet and its acceleration. Assuming that electrons are accelerated in the interaction and making use of the hydrodynamical information, we then compute the high-energy radiation from the cloud, including the absorption of γ-rays in the ambient photon field through pair creation. Results. Jet-cloud interactions can lead to significant γ-ray fluxes in blazars with a broad-line region (BLR), in particular when the cloud expansion and acceleration inside the jet are taken into account. This is caused by 1) the increased shocked area in the jet, which leads to an increase in the energy budget for the non-thermal emission; 2) a more efficient inverse Compton cooling with the boosted photon field of the BLR; and 3) an increased observer luminosity due to Doppler boosting effects. Conclusions. For typical broad-line region parameters, either (i) jet-cloud interactions contribute significantly to the persistent γ-ray emission from blazars or (ii) the BLR is far from spherical or the fraction of energy deposited in non-thermal electrons is smal
Gamma-ray emission from interactions between jets and BLR clouds
Blazars -active galactic nuclei with a jet pointing towards the observer- are the most numerous γ-ray sources detected until date. In this work we show preliminary results of a model in which broad-line region (BLR) clouds penetrate in the jet, producing shocks capable of accelerating relativistic electrons; these electrons emit γ-rays when they interact with the photons coming from the BLR clouds. We calculate semi-analytically the dynamical evolution of a typical cloud inside the jet, the energy distribution of the locally accelerated electrons, and the high-energy emission the latter produce, taking into account relativistic effects. We estimate the dutycycle of these interactions in order to find whether they occur as discrete events or almost continuous. We compare the observed γ-ray fluxes with the ones predicted by our model and discuss the implications in terms of particle acceleration efficiency and mass-loading in the blazar jets
Coherence and anticoherence resonance tunned by noise
We present numerical evidence and a theoretical analysis of the appearance of anticoherence resonance induced by noise, not predicted in former analysis of coherence resonance. We have found that this phenomenon occurs for very small values of the intensity of the noise acting on an excitable system, and we claim that this is a universal signature of a nonmonotonous relaxational behavior near its oscillatory regime. Moreover, we demonstrate that this new phenomenon is totally compatible with the standard situation of coherence resonance appearing at intermediate values of noise intensity
Self-rated health in Europe and its determinants: Does generation matter?
Objectives: To analyse the influence of micro- and macro-factors on self-rated health, and the role of generation on this relationship. Methods: Cross-sectional study using data from European Health Interview Surveys from 14 European countries. Individuals were divided into four generations (“silent generation”, “baby boomers”, and “generation X” and “Y”). We conducted multilevel analyses for each generation to study the influence of individual and national explanatory variables on self-rated health. Results: Age showed an exponential effect in older generations. Education and employment presented the strongest association with low self-rated health, especially in “baby boomers” and women (low education: OR 3.5; 95% CI 3.2–3.9). Tobacco showed a negative effect in younger generations. Overweight and low physical activity were negatively associated with self-rated health regardless of generation. Countries from the Eastern welfare system showed the highest risk of low self-rated health and this association was higher in men for “silent generation” (OR 4.7; 95% CI 3.0–7.6). Conclusions: The influence of individual and national factors on self-rated health varies regarding generation. The target generation and the demographic structure of a country should be taken into account to develop more accurate health policies
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