935 research outputs found
Pointless curves of genus three and four
A curve over a field k is pointless if it has no k-rational points. We show
that there exist pointless genus-3 hyperelliptic curves over a finite field F_q
if and only if q < 26, that there exist pointless smooth plane quartics over
F_q if and only if either q < 24 or q = 29 or q = 32, and that there exist
pointless genus-4 curves over F_q if and only if q < 50.Comment: LaTeX, 15 page
Effects of the galactic magnetic field upon large scale anisotropies of extragalactic Cosmic Rays
The large scale pattern in the arrival directions of extragalactic cosmic
rays that reach the Earth is different from that of the flux arriving to the
halo of the Galaxy as a result of the propagation through the galactic magnetic
field. Two different effects are relevant in this process: deflections of
trajectories and (de)acceleration by the electric field component due to the
galactic rotation. The deflection of the cosmic ray trajectories makes the flux
intensity arriving to the halo from some direction to appear reaching the Earth
from another direction. This applies to any intrinsic anisotropy in the
extragalactic distribution or, even in the absence of intrinsic anisotropies,
to the dipolar Compton-Getting anisotropy induced when the observer is moving
with respect to the cosmic rays rest frame. For an observer moving with the
solar system, cosmic rays traveling through far away regions of the Galaxy also
experience an electric force coming from the relative motion (due to the
rotation of the Galaxy) of the local system in which the field can be
considered as being purely magnetic. This produces small changes in the
particles momentum that can originate large scale anisotropies even for an
isotropic extragalactic flux.Comment: 11 pages, 4 figure
Evidence of threat to European economy and biodiversity following the introduction of an alien pathogen on the fungal–animal boundary
Recent years have seen a global and rapid resurgence of fungal diseases with direct impact on biodiversity and local extinctions of amphibian, coral, or bat populations. Despite similar evidence of population extinction in European fish populations and the associated risk of food aquaculture due to the emerging rosette agent Sphaerothecum destruens, an emerging infectious eukaryotic intracellular pathogen on the fungal–animal boundary, our understanding of current threats remained limited. Long-term monitoring of population decline for the 8-year post-introduction of the fungal pathogen was coupled with seasonal molecular analyses of the 18S rDNA and histological work of native fish species organs. A phylogenetic relationship between the existing EU and US strains using the ribosomal internal transcribed spacer sequences was also carried out. Here, we provide evidence that this emerging parasite has now been introduced via Pseudorasbora parva to sea bass farms, an industry that represents over 400 M€ annually in a Mediterranean region that is already economically vulnerable. We also provide for the first time evidence linking S. destruens to disease and severe declines in International Union for Conservation of Nature threatened European endemic freshwater fishes (i.e. 80% to 90 % mortalities). Our findings are thus of major economic and conservation importance
Catching up with Method and Process Practice: An Industry-Informed Baseline for Researchers
Software development methods are usually not applied by the book.companies are under pressure to continuously deploy software products that meet market needs and stakeholders\u27 requests. To implement efficient and effective development processes, companies utilize multiple frameworks, methods and practices, and combine these into hybrid methods. A common combination contains a rich management framework to organize and steer projects complemented with a number of smaller practices providing the development teams with tools to complete their tasks. In this paper, based on 732 data points collected through an international survey, we study the software development process use in practice. Our results show that 76.8% of the companies implement hybrid methods.company size as well as the strategy in devising and evolving hybrid methods affect the suitability of the chosen process to reach company or project goals. Our findings show that companies that combine planned improvement programs with process evolution can increase their process\u27 suitability by up to 5%
Establishing research priorities for malaria elimination in the context of the emergency response to artemisinin resistance framework-the Cambodian approach
BACKGROUND: Countries of the greater Mekong subregion have made a transition from malaria control to an aim for falciparum and vivax malaria elimination. The elimination of falciparum malaria will have to be achieved against a background of increasing artemisinin and multi-drug resistance. This ambitious goal requires an operational research (OR) agenda that addresses the dynamic challenges encountered on the path to elimination, which will need to be flexible and developed in close relation with the cambodian national programme for parasitology, entomology and malaria control (CNM). In Cambodia, a number of meetings with stakeholders were convened by the CNM and emergency response to artemisinin resistance (ERAR) hub, producing an initial list of priority OR topics. The process and outcome of these meetings are described, which could serve as a template for other countries in the region. METHODS: A landscaping exercise was conducted to gather all past, on-going and planned malaria focussed OR activities conducted by the cambodian research consortium in Cambodia and categorized according to research theme. The six themes included (1) malaria epidemiology, surveillance and response, (2) malaria case management, (3) malaria vector control, (4) malaria behavioural issues, (5) malaria clinical studies, and (6) other vector-borne diseases (dengue, neglected tropical diseases, soil-transmitted helminths). The different themes were discussed in small focus groups, which made an initial prioritization list which was then presented to a plenary group for further discussion. This produced a list of research questions ranked according to priority. RESULTS: OR priorities produced by the thematic groups were discussed in the plenary meeting and given a priority score by group voting. A list of 17 OR questions were developed, finalized and listed, which included questions on surveillance, active case detection and treatment efficacy. CONCLUSION: This paper describes ERAR’s work on supporting Cambodia’s transition to malaria elimination by identifying national operational research priorities. ERAR has initiated and currently plays a critical role in the development of country specific research agendas for malaria elimination. The first example of this has been the described exercise in Cambodia, which could serve a template for setting OR priorities in the wider region
Язык современных СМИ как механизм интерпретации в контексте национальной культуры
Автор, опираясь на различные труды по лингвокультурологии, риторике,
социальной информациологии и информационной политике, рассматривает
язык современных средств массовой информации России как механизм интерпретации национальной культуры. В работе раскрыты понятия интертекстуальности и интерпретации в языке СМИ, обозначена специфика речевого поведения современных журналистов, показаны особенности языковых моделей массовой и качественной прессы.Автор, звертаясь до різноманітних трудів по лінгвокультурології ріторіки,
соціальної інформаціології та інформаційної політики, розглядає мову сучасних
засобів масової інформації Росії як механізм інтерпретації національної культури. В роботі відкрити поняття інтертекстуальністі в мові ЗМІ, визначена специфіка речової поведінки сучасних журналістів, відображені особистості мовних
моделей масової та якісної преси.Drawing on various works on linguistic culturology, rhetorics, social informatiology
and information policy, the author examines the language of modern mass media
on Russia as a mechanism for interpreting national culture. The paper dwells on
the concepts of intertextuality and interpretation in the language of mass media, peculiarities
of modern journalists' speech behaviour and characteristic features of language
models of mass and specialized media
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