26 research outputs found
The Dirichlet Casimir effect for theory in (3+1) dimensions: A new renormalization approach
We calculate the next to the leading order Casimir effect for a real scalar
field, within theory, confined between two parallel plates in three
spatial dimensions with the Dirichlet boundary condition. In this paper we
introduce a systematic perturbation expansion in which the counterterms
automatically turn out to be consistent with the boundary conditions. This will
inevitably lead to nontrivial position dependence for physical quantities, as a
manifestation of the breaking of the translational invariance. This is in
contrast to the usual usage of the counterterms in problems with nontrivial
boundary conditions, which are either completely derived from the free cases or
at most supplemented with the addition of counterterms only at the boundaries.
Our results for the massive and massless cases are different from those
reported elsewhere. Secondly, and probably less importantly, we use a
supplementary renormalization procedure, which makes the usage of any analytic
continuation techniques unnecessary.Comment: JHEP3 format,20 pages, 2 figures, to appear in JHE
Global research priorities for sea turtles : informing management and conservation in the 21st century
Over the past 3 decades, the status of sea turtles and the need for their protection to aid population recovery have increasingly captured the interest of government agencies, non-governmental organisations (NGOs) and the general public worldwide. This interest has been matched by increased research attention, focusing on a wide variety of topics relating to sea turtle biology and ecology, together with the interrelations of sea turtles with the physical and natural environments. Although sea turtles have been better studied than most other marine fauna, management actions and their evaluation are often hindered by the lack of data on turtle biology, human–turtle interactions, turtle population status and threats. In an effort to inform effective sea turtle conservation a list of priority research questions was assembled based on the opinions of 35 sea turtle researchers from 13 nations working in fields related to turtle biology and/or conservation. The combined experience of the contributing researchers spanned the globe as well as many relevant disciplines involved in conservation research. An initial list of more than 200 questions gathered from respondents was condensed into 20 metaquestions and classified under 5 categories: reproductive biology, biogeography, population ecology, threats and conservation strategies
A Multi-center, Dose-escalation Study of Human type I Pancreatic Elastase (PRT-201) Administered after Arteriovenous Fistula Creation
Correlates of Postsecondary Employment Outcomes for Young Adults with Learning Disabilities
Incidence of lesions on Fungiidae corals in the eastern Red Sea is related to water temperature and coastal pollution
A scuticociliate causes mass mortality of Diadema antillarum in the Caribbean Sea
Echinoderm mass mortality events shape marine ecosystems by altering the dynamics among major benthic groups. The sea urchin Diadema antillarum, virtually extirpated in the Caribbean in the early 1980s by an unknown cause, recently experienced another mass mortality beginning in January 2022. We investigated the cause of this mass mortality event through combined molecular biological and veterinary pathologic approaches comparing grossly normal and abnormal animals collected from 23 sites, representing locations that were either affected or unaffected at the time of sampling. Here, we report that a scuticociliate most similar to Philaster apodigitiformis was consistently associated with abnormal urchins at affected sites but was absent from unaffected sites. Experimentally challenging naïve urchins with a Philaster culture isolated from an abnormal, field-collected specimen resulted in gross signs consistent with those of the mortality event. The same ciliate was recovered from treated specimens postmortem, thus fulfilling Koch’s postulates for this microorganism. We term this condition D. antillarum scuticociliatosis
Statistical quantification of the effect of thermal stratification on patterns of dispersion in a freshwater zooplankton community
The vertical distribution of crustacean zooplankton species was examined during 2000 in Windermere, Cumbria. Patterns of dispersion were evaluated quantitatively using two different approaches. Firstly, Morisita’s index was used to test whether patterns of dispersion differed significantly from a state of randomness and, secondly, the relative distribution of zooplankton individuals between the epilimnion and hypolimnion was investigated, for a series of standardised vertical profiles of organism density. All six of the dominant species of planktonic crustaceans showed aggregated patterns of dispersion throughout the year. For most species, patterns of dispersion were affected by the onset and breakdown of thermal stratification in the lake. The degree of aggregation in the vertical plane, measured using Morisita’s index, increased when the lake became thermally stratified. Furthermore, for most species, there was a positive association between the degree of vertical differentiation in abundance across the thermocline, and the degree of temperature differentiation in the stratified water column. The results of the present analysis provide quantitative evidence for the phenomenon known as ‘zooplankton stratification’ and for temporal variation in patterns of zooplankton dispersion