HIV-1 envelope gp41 antibodies can originate from terminal ileum B cells that share cross-reactivity with commensal bacteria.

Monoclonal antibodies derived from blood plasma cells of acute HIV-1-infected individuals are predominantly targeted to the HIV Env gp41 and cross-reactive with commensal bacteria. To understand this phenomenon, we examined anti-HIV responses in ileum B cells using recombinant antibody technology and probed their relationship to commensal bacteria. The dominant ileum B cell response was to Env gp41. Remarkably, a majority (82%) of the ileum anti-gp41 antibodies cross-reacted with commensal bacteria, and of those, 43% showed non-HIV-1 antigen polyreactivity. Pyrosequencing revealed shared HIV-1 antibody clonal lineages between ileum and blood. Mutated immunoglobulin G antibodies cross-reactive with both Env gp41 and microbiota could also be isolated from the ileum of HIV-1 uninfected individuals. Thus, the gp41 commensal bacterial antigen cross-reactive antibodies originate in the intestine, and the gp41 Env response in HIV-1 infection can be derived from a preinfection memory B cell pool triggered by commensal bacteria that cross-react with Env.

Overview of FEED, the feeding experiments end-user database.

The Feeding Experiments End-user Database (FEED) is a research tool developed by the Mammalian Feeding Working Group at the National Evolutionary Synthesis Center that permits synthetic, evolutionary analyses of the physiology of mammalian feeding. The tasks of the Working Group are to compile physiologic data sets into a uniform digital format stored at a central source, develop a standardized terminology for describing and organizing the data, and carry out a set of novel analyses using FEED. FEED contains raw physiologic data linked to extensive metadata. It serves as an archive for a large number of existing data sets and a repository for future data sets. The metadata are stored as text and images that describe experimental protocols, research subjects, and anatomical information. The metadata incorporate controlled vocabularies to allow consistent use of the terms used to describe and organize the physiologic data. The planned analyses address long-standing questions concerning the phylogenetic distribution of phenotypes involving muscle anatomy and feeding physiology among mammals, the presence and nature of motor pattern conservation in the mammalian feeding muscles, and the extent to which suckling constrains the evolution of feeding behavior in adult mammals. We expect FEED to be a growing digital archive that will facilitate new research into understanding the evolution of feeding anatomy.

Carbon markets: Past, present, and future

© 2014 by Annual Reviews.Carbon markets are substantial and expanding. There are many lessons from experience over the past 9 years: fewer free allowances, careful moderation of low and high prices, and a recognition that trading systems require adjustments that have consequences for market participants and market confidence. Moreover, the emerging international architecture features separate emissions trading systems serving distinct jurisdictions. These programs are complemented by a variety of other types of policies alongside the carbon markets. This architecture sits in sharp contrast to the integrated global trading architecture envisioned 15 years ago by the designers of the Kyoto Protocol and raises a suite of new questions. In this new architecture, jurisdictions with emissions trading have to decide how, whether, and when to link with one another, and policy makers must confront how to measure both the comparability of efforts among markets and the comparability between markets and a variety of other policy approaches.

Platelet Counts, Acute Kidney Injury, and Mortality after Coronary Artery Bypass Grafting Surgery.

BACKGROUND: Cardiac surgery requiring cardiopulmonary bypass is associated with platelet activation. Because platelets are increasingly recognized as important effectors of ischemia and end-organ inflammatory injury, the authors explored whether postoperative nadir platelet counts are associated with acute kidney injury (AKI) and mortality after coronary artery bypass grafting (CABG) surgery. METHODS: The authors evaluated 4,217 adult patients who underwent CABG surgery. Postoperative nadir platelet counts were defined as the lowest in-hospital values and were used as a continuous predictor of postoperative AKI and mortality. Nadir values in the lowest 10th percentile were also used as a categorical predictor. Multivariable logistic regression and Cox proportional hazard models examined the association between postoperative platelet counts, postoperative AKI, and mortality. RESULTS: The median postoperative nadir platelet count was 121 × 10/l. The incidence of postoperative AKI was 54%, including 9.5% (215 patients) and 3.4% (76 patients) who experienced stages II and III AKI, respectively. For every 30 × 10/l decrease in platelet counts, the risk for postoperative AKI increased by 14% (adjusted odds ratio, 1.14; 95% CI, 1.09 to 1.20; P < 0.0001). Patients with platelet counts in the lowest 10th percentile were three times more likely to progress to a higher severity of postoperative AKI (adjusted proportional odds ratio, 3.04; 95% CI, 2.26 to 4.07; P < 0.0001) and had associated increased risk for mortality immediately after surgery (adjusted hazard ratio, 5.46; 95% CI, 3.79 to 7.89; P < 0.0001). CONCLUSION: The authors found a significant association between postoperative nadir platelet counts and AKI and short-term mortality after CABG surgery.

Impact of Funding Source on Clinical Trial Results Including Cardiovascular Outcome Trials.

Previous authors have suggested a higher likelihood for industry-sponsored (IS) studies to have positive outcomes than non-IS studies, though the influence of publication bias was believed to be a likely confounder. We attempted to control for the latter using a prepublication database to compare the primary outcome of recent trials based on sponsorship. We used the "advanced search" feature in the clinicaltrials.gov website to identify recently completed phase III studies involving the implementation of a pharmaceutical agent or device for which primary data were available. Studies were categorized as either National Institutes of Health (NIH) sponsored or IS. Results were labeled "favorable" if the results favored the intervention under investigation or "unfavorable" if the intervention fared worse than standard medical treatment. We also performed an independent literature search to identify the cardiovascular trials as a case example and again categorized them into IS versus NIH sponsored. A total of 226 studies sponsored by NIH were found. When these were compared with the latest 226 IS studies, it was found that IS studies were almost 4 times more likely to report a positive outcome (odds ratio [OR] 3.90, 95% confidence interval [CI] 2.6087 to 5.9680, p <0.0001). As a case example of a specialty, we also identified 25 NIH-sponsored and 215 IS cardiovascular trials, with most focusing on hypertension therapy (31.6%) and anticoagulation (17.9%). IS studies were 7 times more likely to report favorable outcomes (OR 7.54, 95% CI 2.19 to 25.94, p = 0.0014). They were also considerably less likely to report unfavorable outcomes (OR 0.11, 95% CI 0.04 to 0.26, p <0.0001). In conclusion, the outcomes of large clinical studies especially cardiovascular differ considerably on the basis of their funding source, and publication bias appears to have limited influence on these findings.

Practice-Level Variation in Outpatient Cardiac Care and Association With Outcomes.

BACKGROUND: Utilization of cardiac services varies across regions and hospitals, yet little is known regarding variation in the intensity of outpatient cardiac care across cardiology physician practices or the association with clinical endpoints, an area of potential importance to promote efficient care. METHODS AND RESULTS: We included 7 160 732 Medicare beneficiaries who received services from 5635 cardiology practices in 2012. Beneficiaries were assigned to practices providing the plurality of office visits, and practices were ranked and assigned to quartiles using the ratio of observed to predicted annual payments per beneficiary for common cardiac services (outpatient intensity index). The median (interquartile range) outpatient intensity index was 1.00 (0.81-1.24). Mean payments for beneficiaries attributed to practices in the highest (Q4) and lowest (Q1) quartile of outpatient intensity were: all cardiac payments (Q4 $1272 vs Q1 $581; ratio, 2.2); cardiac catheterization (Q4 $215 vs Q1 $64; ratio, 3.4); myocardial perfusion imaging (Q4 $253 vs Q1 $83; ratio, 3.0); and electrophysiology device procedures (Q4 $353 vs Q1 $142; ratio, 2.5). The adjusted odds ratios (95% CI) for 1 incremental quartile of outpatient intensity for each outcome was: cardiac surgical/procedural hospitalization (1.09 [1.09, 1.10]); cardiac medical hospitalization (1.00 [0.99, 1.00]); noncardiac hospitalization (0.99 [0.99, 0.99]); and death at 1 year (1.00 [0.99, 1.00]). CONCLUSION: Substantial variation in the intensity of outpatient care exists at the cardiology practice level, and higher intensity is not associated with reduced mortality or hospitalizations. Outpatient cardiac care is a potentially important target for efforts to improve efficiency in the Medicare population.

Thyroid volumes and urinary iodine in Swiss school children, 17 years after improved prophylaxis of iodine deficiency

Salt iodine content in Switzerland was raised from 7.5 to 15 mg per kg in 1980, and since then dietary iodine intake has been considered to be sufficient, even though a slight decrease due to imported food has recently been reported. The aim of this study was to establish normal values for thyroid volumes of school children who can be assumed to have had a sufficient iodine intake all their lifetime. Moreover, the present investigation was undertaken to verify that iodine sufficiency had been achieved equally in two regions each served by one of the two Swiss salt producers. Mean iodine concentration in urine spot samples from school children was 16.1 μg/dl, and it was identical in both the city of Lausanne (n=215) and the city of Solothurn (n=208). Thus it can be stated that in both cities (served by two different salt producers) iodine intake is equal and sufficient. Accordingly, thyroid volumes measured by ultrasound in school children aged 6 to 16 years were the same in both Lausanne (n=202) and Solothurn (n=207). Moreover, the age-adjusted median volumes at the 97th percentiles closely agree with and validate provisional international reference values recently proposed by the World Health Organisation and by the International Council for Control of Iodine Deficiency Disease.

Diseño del colector y ocurrencia de deslizamiento de pezoneras durante el ordeñe de vacas y vaquillonas : (Estudio de caso)

El objetivo de este trabajo fue comparar el número de deslizamientos de pezoneras ocurridos durante el ordeñe con colectores de diferente diseño. La diferencia entre colectores consistió en la posición de los nipples que conectan la tapa del colector con las pezoneras de los cuartos traseros de la ubre. Se utilizó un colector con nipples paralelos (P) y otro con nipples no paralelos (Np) en cada ordeñe, realizando un ordeñe con cada diseño de colector. El diseño P mejoraría el posicionamiento de las pezoneras durante el ordeñe y reduciría la ocurrencia deslizamiento en comparación con el diseño Np. Este trabajo se desarrollo en un tambo comercial en donde se evalúo el número de deslizamientos ocurridos en dos ordeñes consecutivos realizados con uno u otro diseño de colector. Se ordeñaron 411 animales divididos en dos grupos cada vez (215 vacas y 196 vaquillonas), durante cada ordeñe se observo y registró la ocurrencia de deslizamiento de pezoneras en cada animal de cada grupo. El numero de animales con deslizamientos de pezoneras fue mayor cuando se utilizó el colector Np que con P, y menor en vacas que en vaquillonas.

Un aporte econométrico e interpretación microeconómica del trabajo : análisis de la respuesta de trigo a la fertilización nitrogenada en la pampa arenosa

p.215-218

Descripción de la generalización de estudiantes de 3º y 4º de ESO en la resolución de problemas que involucran sucesiones lineales y cuadráticas

Describimos la generalización que logran estudiantes de 3º y 4º de Educación Secundaria Obligatoria (ESO) en la resolución de problemas que involucran sucesiones lineales y cuadráticas. La descripción se centra en aspectos relativos al razonamiento inductivo y a las estrategias inductivas. Estas estrategias permiten describir el proceso seguido en términos de los elementos y los sistemas de representación correspondientes al contenido matemático.

Análisis de las conceptualizaciones erróneas en conceptos de geometría y sistemas de ecuaciones: un estudio con estudiantes universitarios de primer ingreso

En el presente artículo se reportan los resultados de una investigación que clasifica las conceptualizaciones que tienen estudiantes de primer ingreso universitarios de Costa Rica en temas de geometría y sistemas de ecuaciones mediante el modelo SOLO Taxonómico. Este modelo categoriza la actividad mental que realizan los sujetos cuando se enfrentan a una tarea escolar, considerando aspectos cuantitativos y cualitativos. Inicialmente los estudiantes se ubican en los primeros niveles de razonamiento en los temas de geometría y en niveles intermedios en sistemas de ecuaciones, al final los estudiantes mostraron mejoría después de un curso introductorio de matemáticas.

Polya, un clásico en resolución de problemas

El libro que comentamos es de apariencia sencilla, sin visos de trascendencia. Y no sólo porque no es muy extenso (215 páginas), sino por su tono coloquial, cercano y directo, y porque en ningún momento hace referencia a ningún resultado matemático que no sea conocido por cualquier profesor de matemáticas de los niveles primario y medio.

Learning from experience

Training courses for researchers are discussed in some detail. The preparation of researchers and of statisticians for consulting sessions, and the opportunities such sessions provide for training, are considered.

Viscoelastic flow through a planar contraction using a semi-Lagrangian finite volume method

A semi-Lagrangian finite volume scheme for solving viscoelastic flow problems is presented. A staggered grid arrangement is used in which the dependent variables are located at different mesh points in the computational domain. The convection terms in the momentum and constitutive equations are treated using a semi-Lagrangian approach in which particles on a regular grid are traced backwards over a single time-step. The method is applied to the 4 : 1 planar contraction problem for an Oldroyd B fluid for both creeping and inertial flow conditions. The development of vortex behaviour with increasing values of We is analyzed.