3,591 research outputs found
Seasonal variation and impact of waste-water lagoons as larval habitat on the population dynamics of Culicoides sonorensis (Diptera:Ceratpogonidae) at two dairy farms in northern California.
The Sacramento (northern Central) Valley of California (CA) has a hot Mediterranean climate and a diverse ecological landscape that is impacted extensively by human activities, which include the intensive farming of crops and livestock. Waste-water ponds, marshes, and irrigated fields associated with these agricultural activities provide abundant larval habitats for C. sonorensis midges, in addition to those sites that exist in the natural environment. Within this region, C. sonorensis is an important vector of bluetongue (BTV) and related viruses that adversely affect the international trade and movement of livestock, the economics of livestock production, and animal welfare. To characterize the seasonal dynamics of immature and adult C. sonorensis populations, abundance was monitored intensively on two dairy farms in the Sacramento Valley from August 2012- to July 2013. Adults were sampled every two weeks for 52 weeks by trapping (CDC style traps without light and baited with dry-ice) along N-S and E-W transects on each farm. One farm had large operational waste-water lagoons, whereas the lagoon on the other farm was drained and remained dry during the study. Spring emergence and seasonal abundance of adult C. sonorensis on both farms coincided with rising vernal temperature. Paradoxically, the abundance of midges on the farm without a functioning waste-water lagoon was increased as compared to abundance on the farm with a waste-water lagoon system, indicating that this infrastructure may not serve as the sole, or even the primary larval habitat. Adult midges disappeared from both farms from late November until May; however, low numbers of parous female midges were detected in traps set during daylight in the inter-seasonal winter period. This latter finding is especially critical as it provides a potential mechanism for the "overwintering" of BTV in temperate regions such as northern CA. Precise documentation of temporal changes in the annual abundance and dispersal of Culicoides midges is essential for the creation of models to predict BTV infection of livestock and to develop sound abatement strategies
Lifelong learning and schools as community learning centres : key aspects of a national curriculum draft policy framework for Malta
The island of Malta has been engaged in policy document formulations for curriculum renewal in the country’s educational system (4-16 years of age) since 1988 when the first National Minimum Curriculum (henceforth NMC) was launched (Wain, 1991; Borg et al, 1995). In 1999 a revamped NMC (Ministry of Education, 1999) was developed following a long process of consultation involving various stages and stakeholders. It was a compromise document (Borg & Mayo, 2006) which emerged as a result of reactions to a more radical and coherent draft document produced in 1988.
Both curricular documents were subject to debates and critiques (Wain, 1991; Darmanin, 1993; Borg et al, 1995; Giordmaina, 2000; Borg and Mayo, 2006). More recently a series of volumes providing guidelines, key principles and aims for a national curriculum framework (henceforth NCF) have been produced (MEEF, 2011a,b,c,d) and are currently the target of debate and the focus of reactions by various stakeholders in education including teachers who were asked to read the volumes and provide reactions in the form of answers to a set questionnaire. In this paper, I will focus on one aspect of the documents, the first of its three aims: ‘Learners who are capable of successfully developing their full potential as lifelong learners.’ It is that aspect of the framework documents that falls within the purview of the title for this special issue. The use of this notion attests to the influence of the EU’s policy communications on member states, Malta having joined the Union in 2004 (Mayo, 2007).peer-reviewe
Evolution Equation of Phenotype Distribution: General Formulation and Application to Error Catastrophe
An equation describing the evolution of phenotypic distribution is derived
using methods developed in statistical physics. The equation is solved by using
the singular perturbation method, and assuming that the number of bases in the
genetic sequence is large. Applying the equation to the mutation-selection
model by Eigen provides the critical mutation rate for the error catastrophe.
Phenotypic fluctuation of clones (individuals sharing the same gene) is
introduced into this evolution equation. With this formalism, it is found that
the critical mutation rate is sometimes increased by the phenotypic
fluctuations, i.e., noise can enhance robustness of a fitted state to mutation.
Our formalism is systematic and general, while approximations to derive more
tractable evolution equations are also discussed.Comment: 22 pages, 2 figure
Are manufacturers sharing data as promised?
Over the past two years drug and device manufacturers have been among the most vocal contributors to the discussion about transparency of clinical trial data. In 2013 GlaxoSmithKline (GSK) established its Clinical Study Data Request system to share participant level data, and now 11 other companies are listed as contributors to it (www.clinicalstudydatarequest.com). Other companies have developed similar systems of their own,but it is difficult to evaluate how they are working or even to decide on what basis they should be judged
Black hole polarization and new entropy bounds
Zaslavskii has suggested how to tighten Bekenstein's bound on entropy when
the object is electrically charged. Recently Hod has provided a second tighter
version of the bound applicable when the object is rotating. Here we derive
Zaslavskii's optimized bound by considering the accretion of an ordinary
charged object by a black hole. The force originating from the polarization of
the black hole by a nearby charge is central to the derivation of the bound
from the generalized second law. We also conjecture an entropy bound for
charged rotating objects, a synthesis of Zaslavskii's and Hod's. On the basis
of the no hair principle for black holes, we show that this last bound cannot
be tightened further in a generic way by knowledge of ``global'' conserved
charges, e.g., baryon number, which may be borne by the object.Comment: 21 pages, RevTex, Regularization of potential made clearer. Error in
energy of the particle corrected with no consequence for final conclusions.
New references adde
A Randomized, Controlled, Supervised, Excerise Trial in Young Overweight Men and Women: The Midwest Exercise Trial II (MET2)
We evaluated weight loss response to 16 months of supervised exercise (45 minutes/d, 5 d/wk, 75% heart-rate-reserve) in sedentary, overweight/obese participants without energy restriction in the Midwest Exercise Trial (MET1). Results indicated men lost weight, women did not. The gender differences were associated with differences in the energy expenditure of exercise (EEEx) (men = 667 ± 116; women = 439 ± 88 kcal/session) when exercise was prescribed by frequency, intensity and duration. MET2 is a randomized control trial designed and powered to examine differences in weight loss and gender in response to EEEx for men and women of 400 or 600 kcal/session, 5d/wk, for 10 months without energy restriction. One hundred forty one participants will be randomized to 1 of 2 exercise groups or a non-exercise control. EEEx will be verified by indirect calorimetry monthly during the intervention. This study will evaluate: (1) the weight change response to two levels of EEEx versus non-exercise control; (2) gender differences in weight response to two levels of EEEx; (3) potential compensatory changes in energy intake and/or daily physical activity that may explain the observed weight changes. Results from this study may impact how exercise is prescribed for weight loss and prevention of weight regain and may clarify if men and women differ in response to exercise
Weight management by phone conference call: A comparision with a traditional face-to-face clinic. Rationale and design for a randomized equivalence trial
State-of-the-art treatment for weight management consists of a behavioral intervention to facilitate decreased energy intake and increased physical activity. These interventions are typically delivered face-to-face (FTF) by a health educator to a small group of participants. There are numerous barriers to participation in FTF clinics including availability, scheduling, the expense and time required to travel to the clinic site, and possible need for dependent care. Weight management clinics delivered by conference call have the potential to diminish or eliminate these barriers. The conference call approach may also reduce burden on providers, who could conduct clinic groups from almost any location without the expenses associated with maintaining FTF clinic space. A randomized trial will be conducted in 395 overweight/obese adults (BMI 25–39.9 kg/m2) to determine if weight loss (6 months) and weight maintenance (12 months) are equivalent between weight management interventions utilizing behavioral strategies and pre-packaged meals delivered by either a conference call or the traditional FTF approach. The primary outcome, body weight, will be assessed at baseline, 6, 12 and 18 months. Secondary outcomes including waist circumference, energy and macronutrient intake, and physical activity and will be assessed on the same schedule. In addition, a cost analysis and extensive process evaluation will be completed
Binary-induced collapse of a compact, collisionless cluster
We improve and extend Shapiro's model of a relativistic, compact object which
is stable in isolation but is driven dynamically unstable by the tidal field of
a binary companion. Our compact object consists of a dense swarm of test
particles moving in randomly-oriented, initially circular, relativistic orbits
about a nonrotating black hole. The binary companion is a distant, slowly
inspiraling point mass. The tidal field of the companion is treated as a small
perturbation on the background Schwarzschild geometry near the hole; the
resulting metric is determined by solving the perturbation equations of Regge
and Wheeler and Zerilli in the quasi-static limit. The perturbed spacetime
supports Bekenstein's conjecture that the horizon area of a near-equilibrium
black hole is an adiabatic invariant. We follow the evolution of the system and
confirm that gravitational collapse can be induced in a compact collisionless
cluster by the tidal field of a binary companion.Comment: 9 Latex pages, 14 postscript figure
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