1,433 research outputs found
Ecological and behavioral drivers of supplemental feeding use by roe deer Capreolus capreolus in a peri-urban context
Winter supplemental feeding of ungulates potentially alters their use of resources and
ecological interactions, yet relatively little is known about the patterns of feeding sites use by target
populations. We used camera traps to continuously monitor winter and spring feeding site use in a
roe deer population living in a peri-urban area in Northern Italy. We combined circular statistics with
generalized additive and linear mixed models to analyze the diel and seasonal pattern of roe deer
visits to feeding sites, and the behavioral drivers influencing visit duration. Roe deer visits peaked at
dawn and dusk, and decreased from winter to spring when vegetation regrows and temperature
increases. Roe deer mostly visited feeding sites solitarily; when this was not the case, they stayed
longer at the site, especially when conspecifics were eating, but maintained a bimodal diel pattern
of visits. These results support an opportunistic use of feeding sites, following seasonal cycles and
the roe deer circadian clock. Yet, the attractiveness of these artificial resources has the potential to
alter intra-specific relationships, as competition for their use induces gatherings and may extend the
contact time between individuals, with potential behavioral and epidemiological consequences
High-spatial-resolution passive microwave sounding systems
During this period the emphasis was on the following: (1) further design, construction, and testing of the improved 54-GHz portion of the 54-118 GHz microwave temperature sounder (MTS) aircraft radiometer system in preparation for ER-2 observations in July 1991; and (2) final analysis and documentation of procedures for detecting and analyzing thermal waves in our 118-GHz MTS imagery. In addition, we have new unpublished measurements of dry-air attenuation at frequencies of 54 to 66 GHz and over a temperature range of 280K to 326K; these measurements should enable us to improve further our atmospheric transmittance models. It was further noted that the proposed SSMIS conical-scanning microwave spectrometer on the military DMSP Block 5D-3 spacecraft designed to measure stratospheric and mesospheric temperature profiles will be observing the Zeeman-split oxygen lines with sufficient spectral resolution that the changing Doppler shifts with view angle will substantially degrade the potential system performance unless remedied; this was briefly studied and documented
Additive energy forward curves in a Heath-Jarrow-Morton framework
One of the peculiarities of power and gas markets is the delivery mechanism
of forward contracts. The seller of a futures contract commits to deliver, say,
power, over a certain period, while the classical forward is a financial
agreement settled on a maturity date. Our purpose is to design a
Heath-Jarrow-Morton framework for an additive, mean-reverting, multicommodity
market consisting of forward contracts of any delivery period. The main
assumption is that forward prices can be represented as affine functions of a
universal source of randomness. This allows us to completely characterize the
models which prevent arbitrage opportunities: this boils down to finding a
density between a risk-neutral measure , such that the prices of
traded assets like forward contracts are true -martingales, and the
real world probability measure , under which forward prices are
mean-reverting. The Girsanov kernel for such a transformation turns out to be
stochastic and unbounded in the diffusion part, while in the jump part the
Girsanov kernel must be deterministic and bounded: thus, in this respect, we
prove two results on the martingale property of stochastic exponentials. The
first allows to validate measure changes made of two components: an
Esscher-type density and a Girsanov transform with stochastic and unbounded
kernel. The second uses a different approach and works for the case of
continuous density. We apply this framework to two models: a generalized
Lucia-Schwartz model and a cross-commodity cointegrated market.Comment: 28 page
Coverage, efficacy or dosing interval: which factor predominantly influences the impact of routine childhood vaccination for the prevention of varicella? A model-based study for Italy
Background: Varicella is a highly infectious disease with a significant public health and economic burden, which can be prevented with childhood routine varicella vaccination. Vaccination strategies differ by country. Some factors are known to play an important role (number of doses, coverage, dosing interval, efficacy and catch-up programmes), however, their relative impact on the reduction of varicella in the population remains unclear. This paper aims to help policy makers prioritise the critical factors to achieve the most successful vaccination programme with the available budget. Methods: Scenarios assessed the impact of different vaccination strategies on reduction of varicella disease in the population. A dynamic transmission model was used and adapted to fit Italian demographics and population mixing patterns. Inputs included coverage, number of doses, dosing intervals, first-dose efficacy and availability of catch-up programmes, based on strategies currently used or likely to be used in different countries. The time horizon was 30 years. Results: Both one- and two-dose routine varicella vaccination strategies prevented a comparable number of varicella cases with complications, but two-doses provided broader protection due to prevention of a higher number of milder varicella cases. A catch-up programme in susceptible adolescents aged 10-14 years old reduced varicella cases by 27-43 % in older children, which are often more severe than in younger children. Coverage, for all strategies, sustained at high levels achieved the largest reduction in varicella. In general, a 20 % increase in coverage resulted in a further 27-31 % reduction in varicella cases. When high coverage is reached, the impact of dosing interval and first-dose vaccine efficacy had a relatively lower impact on disease prevention in the population. Compared to the long (11 years) dosing interval, the short (5 months) and medium (5 years) interval schedules reduced varicella cases by a further 5-13 % and 2-5 %, respectively. Similarly, a 10 % increase in first-dose efficacy (from 65 to 75 % efficacy) prevented 2-5 % more varicella cases, suggesting it is the least influential factor when considering routine varicella vaccination. Conclusions: Vaccination strategies can be implemented differently in each country depending on their needs, infrastructure and healthcare budget. However, ensuring high coverage remains the critical success factor for significant prevention of varicella when introducing varicella vaccination in the national immunisation programme
Economic burden of HPV9-related diseases : a real world cost analysis from Italy
The objectives of this study were to estimate the economic burden of HPV in Italy, accounting for total direct medical costs associated with nine major HPV-related diseases, and to provide a measure of the burden attributable to HPV 6, 11, 16, 18, 31, 33, 45, 52, 58 infections
High spatial resolution passive microwave sounding systems
Two extensive series of flights aboard the ER-2 aircraft were conducted with the MIT 118 GHz imaging spectrometer together with a 53.6 GHz nadir channel and a TV camera record of the mission. Other microwave sensors, including a 183 GHz imaging spectrometer were flown simultaneously by other research groups. Work also continued on evaluating the impact of high-resolution passive microwave soundings upon numerical weather prediction models
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