Co-Evolution of quasispecies: B-cell mutation rates maximize viral error catastrophes

Co-evolution of two coupled quasispecies is studied, motivated by the competition between viral evolution and adapting immune response. In this co-adaptive model, besides the classical error catastrophe for high virus mutation rates, a second ``adaptation-'' catastrophe occurs, when virus mutation rates are too small to escape immune attack. Maximizing both regimes of viral error catastrophes is a possible strategy for an optimal immune response, reducing the range of allowed viral mutation rates to a minimum. From this requirement one obtains constraints on B-cell mutation rates and receptor lengths, yielding an estimate of somatic hypermutation rates in the germinal center in accordance with observation.Comment: 4 pages RevTeX including 2 figure

Determinación del bienestar animal en equinos de tracción a sangre en barrios periféricos de la ciudad de Corrientes, Argentina

In many cities of Argentina, equine-drawn carts represent an economic livelihood for low-income families. These equines are generally in inadequate physical condition, which results in a sub-optimal performance and a serious detriment to their welfare. The aim of the present work was to determine the animal welfare state of working equines in peripheral neighborhoods of the City of Corrientes Capital, Argentina, using direct and indirect indicators. The population (n=42) presented an average age of 6.8 years and within it a 60% were stallions. Forty five percent of the animals presented suboptimal nutritional status, 43% of the cases presented oral alterations, 67% had skin lesions and 74% had inadequate hoof conditions. Almost all of the animals were alert to the approach of the observer, some reacting aggressively and others expressing abnormal behaviors. Equines were usually used during the morning hours, with loads of brick and sand being the most frequently recorded. According to their caretakers, the animals receive veterinary care on a regular basis, registering an alarming tendency to release them in empty lots, public squares or roads during rest hours. The sources of water and food, constituted by river water, alfalfa and corn, added to grazing during the rest, are positioned as the main alternatives. Thus, it is observed that the welfare state of the equines sampled in the city was between regular and bad, being evident the need for training of caretakers on responsible ownership and joint work between veterinarians and public agencies to address the problem.En numerosas ciudades de la Argentina, la tracción animal o también conocida como tracción a sangre (TAS) representa un medio de sustento económico para familias de escasos recursos; los equinos de la actividad generalmente se hallan en condiciones físicas inadecuadas, lo que resulta en un sub-óptimo desempeño y en un serio detrimento de su bienestar. El presente trabajo busca determinar el bienestar animal de los equinos de trabajo en barrios periféricos de la Ciudad de Corrientes Capital, Argentina, utilizando indicadores directos e indirectos. Los primeros se obtuvieron a través del examen físico y comportamental, mientras que los segundos, mediante encuestas a los tutores. La población (n=42) presentó un promedio de edad de 6,8 años y dentro de ella se identificó una subpoblación compuesta por un 60% de machos enteros. Se registró un 45% de animales con estados nutricionales subóptimos, un 43% de pacientes con alteraciones bucales, 67% con lesiones cutáneas y un 74% con condiciones inadecuadas de cascos. Casi la totalidad de los animales se mostraron alerta al acercamiento humano, reaccionando algunos de forma agresiva y otros con conductas anormales. Los animales son usualmente utilizados en horas de la mañana, siendo las cargas de ladrillo y arena las más frecuentemente registradas. Las encuestas revelaron que los animales reciben atención veterinaria, registrándose una alarmante tendencia a la liberación en baldíos, plazas o en la vía pública durante las horas de descanso. Las fuentes de agua y alimentos, constituidas por el agua de río, alfalfa y maíz se posicionan como las principales alternativas. Se observa así que el estado de bienestar de los equinos muestreados en la ciudad es regular a malo, siendo evidente la necesidad de capacitación de los tutores sobre tenencia responsable y el trabajo conjunto entre médicos veterinarios y organismos públicos para abordar la problemática

Student Satisfaction and Performance in an Online Teacher Certification Program

The article presents a study which demonstrates the effectiveness of an online post baccalaureate teacher certification program developed by a Wisconsin university. The case method approach employing multiple methods and multiple data sources were used to investigate the degree to which pre-service teachers were prepared to teach. It was concluded that the study supports online delivery as an effective means of teacher preparation, but it was limited in the number of students followed into their first year of teaching

Planning for Sustainability in Small Municipalities: The Influence of Interest Groups, Growth Patterns, and Institutional Characteristics

How and why small municipalities promote sustainability through planning efforts is poorly understood. We analyzed ordinances in 451 Maine municipalities and tested theories of policy adoption using regression analysis.We found that smaller communities do adopt programs that contribute to sustainability relevant to their scale and context. In line with the political market theory, we found that municipalities with strong environmental interests, higher growth, and more formal governments were more likely to adopt these policies. Consideration of context and capacity in planning for sustainability will help planners better identify and benefit from collaboration, training, and outreach opportunities

Modeling Supply Networks and Business Cycles as Unstable Transport Phenomena

Physical concepts developed to describe instabilities in traffic flows can be generalized in a way that allows one to understand the well-known instability of supply chains (the so-called ``bullwhip effect''). That is, small variations in the consumption rate can cause large variations in the production rate of companies generating the requested product. Interestingly, the resulting oscillations have characteristic frequencies which are considerably lower than the variations in the consumption rate. This suggests that instabilities of supply chains may be the reason for the existence of business cycles. At the same time, we establish some link to queuing theory and between micro- and macroeconomics.Comment: For related work see http://www.helbing.or

The FIELDS Instrument Suite for Solar Probe Plus: Measuring the Coronal Plasma and Magnetic Field, Plasma Waves and Turbulence, and Radio Signatures of Solar Transients.

NASA's Solar Probe Plus (SPP) mission will make the first in situ measurements of the solar corona and the birthplace of the solar wind. The FIELDS instrument suite on SPP will make direct measurements of electric and magnetic fields, the properties of in situ plasma waves, electron density and temperature profiles, and interplanetary radio emissions, amongst other things. Here, we describe the scientific objectives targeted by the SPP/FIELDS instrument, the instrument design itself, and the instrument concept of operations and planned data products

First Measurement of the Transverse Spin Asymmetries of the Deuteron in Semi-Inclusive Deep Inelastic Scattering

First measurements of the Collins and Sivers asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarized 6-LiD target are presented. The data were taken in 2002 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160 GeV/c. The Collins asymmetry turns out to be compatible with zero, as does the measured Sivers asymmetry within the present statistical errors.Comment: 6 pages, 2 figure

The Polarised Valence Quark Distribution from semi-inclusive DIS

The semi-inclusive difference asymmetry A^{h^{+}-h^{-}} for hadrons of opposite charge has been measured by the COMPASS experiment at CERN. The data were collected in the years 2002-2004 using a 160 GeV polarised muon beam scattered off a large polarised ^6LiD target and cover the range 0.006 < x < 0.7 and 1 < Q^2 < 100 (GeV/c)^2. In leading order QCD (LO) the asymmetry A_d^{h^{+}-h^{-}} measures the valence quark polarisation and provides an evaluation of the first moment of Delta u_v + Delta d_v which is found to be equal to 0.40 +- 0.07 (stat.) +- 0.05 (syst.) over the measured range of x at Q^2 = 10 (GeV/c)^2. When combined with the first moment of g_1^d previously measured on the same data, this result favours a non-symmetric polarisation of light quarks Delta u-bar = - Delta d-bar at a confidence level of two standard deviations, in contrast to the often assumed symmetric scenario Delta u-bar = Delta d-bar = Delta s-bar = Delta s.Comment: 7 pages, 3 figures, COMPASS, revised: details added, author list update

An Overview of the 2014 ALMA Long Baseline Campaign

A major goal of the Atacama Large Millimeter/submillimeter Array (ALMA) is to make accurate images with resolutions of tens of milliarcseconds, which at submillimeter (submm) wavelengths requires baselines up to ~15 km. To develop and test this capability, a Long Baseline Campaign (LBC) was carried out from September to late November 2014, culminating in end-to-end observations, calibrations, and imaging of selected Science Verification (SV) targets. This paper presents an overview of the campaign and its main results, including an investigation of the short-term coherence properties and systematic phase errors over the long baselines at the ALMA site, a summary of the SV targets and observations, and recommendations for science observing strategies at long baselines. Deep ALMA images of the quasar 3C138 at 97 and 241 GHz are also compared to VLA 43 GHz results, demonstrating an agreement at a level of a few percent. As a result of the extensive program of LBC testing, the highly successful SV imaging at long baselines achieved angular resolutions as fine as 19 mas at ~350 GHz. Observing with ALMA on baselines of up to 15 km is now possible, and opens up new parameter space for submm astronomy.Comment: 11 pages, 7 figures, 2 tables; accepted for publication in the Astrophysical Journal Letters; this version with small changes to affiliation

Measurement of the Longitudinal Spin Transfer to Lambda and Anti-Lambda Hyperons in Polarised Muon DIS

The longitudinal polarisation transfer from muons to lambda and anti-lambda hyperons, D_LL, has been studied in deep inelastic scattering off an unpolarised isoscalar target at the COMPASS experiment at CERN. The spin transfers to lambda and anti-lambda produced in the current fragmentation region exhibit different behaviours as a function of x and xF . The measured x and xF dependences of D^lambda_LL are compatible with zero, while D^anti-lambda_LL tends to increase with xF, reaching values of 0.4 - 0.5. The resulting average values are D^lambda_LL = -0.012 +- 0.047 +- 0.024 and D^anti-lambda_LL = 0.249 +- 0.056 +- 0.049. These results are discussed in the frame of recent model calculations.Comment: 13 pages, 7 figure