187 research outputs found

    Effective chemical potential in spontaneous baryogenesis

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    Models of spontaneous baryogenesis have an interaction term μθjBμ\partial_\mu\theta j^\mu_B in the Lagrangian, where jBμj^\mu_B is the baryonic current and θ\theta can be a pseudo-Nambu-Goldstone boson. Since the time component of this term, θ˙jB0\dot{\theta} j^0_B, equals θ˙nB\dot{\theta} n_B for a spatially homogeneous current, it is usually argued that this term implies a splitting in the energy of baryons and antibaryons thereby providing an effective chemical potential for baryon number. In thermal equilibrium, one {then obtains} nBθ˙T2n_B \sim \dot{\theta} T^2. We however argue that a term of this form in the Lagrangian does not contribute to the single particle energies of baryons and antibaryons. We show this for both fermionic and scalar baryons. But, similar to some recent work, we find that despite the above result the baryon number density obtained from a Boltzmann equation analysis can be proportional to θ˙T2\dot{\theta} T^2. Our arguments are very different from that in the standard literature on spontaneous baryogenesis.Comment: 16 pages, matches with the published versio

    UVODNIK 2015: NAPORI PREMA BOLJOJ KVALITETI ČASOPISA Croatian Journal of Fisheries (Ribarstvo)

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    By changing its editorial system, the Croatian Journal of Fisheries is moving toward more rigorous review which will sub- sequently strengthen its quality and impact. This editorial provides information on the published articles in 2014 as well as a list of reviewers who participated in the review process. Many papers were submitted as short communications to the Threatened Fishes of the World (TFW) series in 2014. To be more useful to the broader scientific community, guidelines about preparation of manuscripts for the TFW series based on The IUCN Red List of Threatened SpeciesTM is provided. Also, after having several years of experience in reviewing, processing and editing of manuscripts, it has been noted that authors repeat the same mistakes. Therefore, we present here a paper that discusses the most common mistakes encountered dur- ing manuscript preparation which can result in its rejection.Promjenom uredničkog sustava i načina rada časopis se kreće u pravcu rigoroznijih recenzija te sukladno, jačanju kvalitete i utjecaja. Ovaj uvodnik daje podatke objavljenih članaka u 2014. godini prema tematskim cjelinama kao i popis recenzenata koji su sudjelovali u recenzijskom postupku. Mnogo kratkih članaka je pristiglo iz tematike ugroženih ribljih vrsta u svijetu u 2014. Stoga su ovdje date detaljne upute za pripremu takvih članaka, baziranih na podacima navedenim u The IUCN Red List of Threatened SpeciesTM , kako bi bili korisniji za širu znanstvenu zajednicu. Također, nakon više godina praćenja pridošlih članaka, autori često i kontinuirano griješe u oblikovanju samog članka. Stoga je dat i prikaz najčešćih pogrešaka kod prijavljenih radova što može rezultirati istovremenim odbijanjem rada kao potencijalnog članka za publiciranje

    The tragedy of the nature photography commons

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    Over the last few decades, photography has become a crucial tool in the mainstreaming of biodiversity and its conservation. Today, it would be almost impossible to find any conservation outreach or marketing materials that do not include at least a few photographs. This em-phasis on photographic material is well justified, as there is evidence that photographs can have an important im-pact in our perceptions, attitudes and even behaviour to-wards nature (Kalof, Zammit-Lucia and Kelly 2011; Myers Jr., 2006). Examples of this are the efforts of the Sierra Club to establish some of the world’s first pro-tected areas in the USA; National Geographic’s coverage of the “Megatransect” trek by ecologist Michael Fay across the Congo basin; or the recent media reports on the large scale killing of Amur Falcons in the of Nagaland, India (Dalvi and Sreenivasan, 2012; Myers Jr., 2006). Such encouraging outcomes have lead to the creation of the field of “conservation photography” and to the forma-tion of organizations such as the International League of Conservation Photographers, who work specifically to disseminate the need for biodiversity conservation (Myers Jr., 2006

    Growth Stress Induced Tunability of Dielectric Constant in Thin Films

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    It is demonstrated here that growth stress has a substantial effect on the dielectric constant of zirconia thin films. The correct combination of parameters - phase, texture and stress - is shown to yield films with high dielectric constant and best reported equivalent oxide thickness of 0.8 nm. The stress effect on dielectric constant is twofold, firstly, by the effect on phase transitions and secondly by the effect on interatomic distances. We discuss and explain the physical mechanisms involved in the interplay between the stress, phase changes and the dielectric constant in detail.Comment: 11 pages, 5 figure

    Bortezomib in Kidney Transplantation

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    Although current therapies for pretransplant desensitization and treatment of antibody-mediated rejection (AMR) have had some success, they do not specifically deplete plasma cells that produce antihuman leukocyte antigen (HLA) antibodies. Bortezomib, a proteasome inhibitor approved for the treatment of multiple myeloma (a plasma cell neoplasm), induces plasma cell apoptosis. In this paper we review the current body of literature regarding the use of this biological agent in the field of transplantation. Although limited experience with bortezomib may seem to show promise in the realm of transplant recipients desensitization and treatment of AMR, there is also experience that may suggest otherwise. Bortezomib's role in desensitization protocols and treatment of AMR will be defined better as more clinical data and trials become available

    Evolution in the dark: Unexpected genetic diversity and morphological stasis in the blind, aquifer-dwelling catfish Horaglanis

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    The lateritic aquifers of the southern Indian state of Kerala harbour a unique assemblage of enigmatic stygobitic fishes which are encountered very rarely, only when they surface during the digging and cleaning of homestead wells. Here, we focus on one of the most unusual members of this group, the catfish Horaglanis, a genus of rarely-collected, tiny, blind, pigment less, and strictly aquifer-residing species. A six-year exploratory and citizen-science backed survey supported by molecular phylogenetic analysis reveals novel insights into the diversity, distribution and population structure of Horaglanis. The genus is characterized by high levels of intraspecific and interspecific genetic divergence, with phylogenetically distinct species recovered above a 7.0% genetic-distance threshold in the mitochondrial cytochrome oxidase subunit 1 gene. Contrasting with this deep genetic divergence, however, is a remarkable stasis in external morphology. We identify and describe a new cryptic species, Horaglanis populi, a lineage that is the sister group of all currently known species. All four species are represented by multiple haplotypes. Mismatch distribution reveals that populations have not experienced recent expansions

    Western Ghats’ fish fauna in peril: are pseudo conservationist attitudes to be blamed?

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    Use of threatened species in research – be it for taxonomy, biology or population studies, has always invoked much debate. As a result, the Species Survival Commission of the International Union for Conservation of Nature (IUCN) developed a set of guidelines entitled ‘IUCN Policy Statement on Research Involving Species at Risk of Extinction’ with special reference to scientific collecting of threatened species1

    Assessing recreational fisheries in an emerging economy: Knowledge,perceptions and attitudes of catch-and-release anglers in India

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    ABSTRACT: Across the globe, catch-and-release (C&R) angling represents a leisure activity indulged by millions. The practice of C&R is commonly advocated by conservation managers because of its potential to protect local fish populations from a range of anthropogenic threats, including over-fishing. In India, C&R angling in fresh waters has a history dating back to colonial times. Despite this, little is known about the current state of the sector. To address this, an online web-based survey was conducted to target C&R anglers who fish in Indian rivers to assess their knowledge, attitudes and perceptions relating to the status of India's freshwater C&R fisheries. From a total of 148 responses, factors such as angling quality (score of 4.6/5.0); aesthetics of surroundings (4.6/5.0), presence of other wildlife (4.4/5.0), fishery management practices (4.6/5.0) and socioeconomic benefits (4.4/5.0) were evaluated. Over 65% (n = 148) of the anglers reported an observed decrease in the quality of fishing (e.g. a reduction in the size and/or numbers of fish available for capture). Respondents also considered deforestation (score of 4.2/5.0), water abstraction (4.4/5.0), pollution (4.4/5.0), hydropower projects (4.2/5.0) and destructive fishing techniques (4.7/5.0) as factors which threaten both the habitat and species they target. C&R practitioners were largely united regarding the benefits and willingness to contribute both their time and financial input to support conservation initiatives (score of 4.7/5.0). The current study provides the first overview of the status of C&R angling in India and explores challenges, opportunities, and priorities for future resource management

    Preventing and controlling nonnative species invasions to bend the curve of global freshwater biodiversity loss

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    The Emergency Recovery Plan for freshwater biodiversity recognizes that addressing nonnative species is one of six principal actions needed to bend the curve in freshwater biodiversity loss. This is because introduction rates of nonnative species continue to accelerate globally and where these species develop invasive populations, they can have severe impacts on freshwater biodiversity. The most effective management measure to protect freshwater biodiversity is to prevent introductions of nonnative species. Should a nonnative species be introduced, however, then its early detection and the implementation of rapid reaction measures can avoid it establishing and dispersing. If these measures are unsuccessful and the species becomes invasive, then control and containment measures can minimize its further spread and impact. Minimizing further spread and impact includes control methods to reduce invader abundance and containment methods such as screening of invaded sites and strict biosecurity to avoid the invader dispersing to neighbouring basins. Thesemanagement actions have benefitted from developments in invasion risk assessment that can prioritize species according to their invasion risk and, for species already invasive, ensure that management actions are commensurate with assessed risk. The successful management of freshwater nonnative species still requires the overcoming of some implementation challenges, including nonnative species often being a symptom of degraded habitats rather than the main driver of ecological change, and eradication methods often being non-species specific. Given the multiple anthropogenic stressors in freshwaters, nonnative species management must work with other restoration strategies if it is to deliver the Emergency Recovery Plan for freshwater biodiversity
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