bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distinct and concurrent pathways of Pol II‐ and Pol IV‐dependent siRNA biogenesis at a repetitive trans‐silencer locus in Arabidopsis thaliana
Authors: Sasaki Taku , Lee Tzuu‐fen , Liao Wen‐Wei , Naumann Ulf , Liao Jo‐Ling , Eun Changho , Huang Ya‐Yi , Fu Jason L. , Chen Pao‐Yang , Meyers Blake C. , Matzke Antonius J.M. , Matzke Marjori 
Published: May 2014

SummaryShort interfering RNAs (siRNAs) homologous to transcriptional regulatory regions can induce RNA‐directed DNA methylation (RdDM) and transcriptional gene silencing (TGS) of target genes. In our system, siRNAs are produced by transcribing an inverted DNA repeat (IR) of enhancer sequences, yielding a hairpin RNA that is processed by several Dicer activities into siRNAs of 21–24 nt. Primarily 24‐nt siRNAs trigger RdDM of the target enhancer in trans and TGS of a downstream GFP reporter gene. We analyzed siRNA accumulation from two different structural forms of a trans‐silencer locus in which tandem repeats are embedded in the enhancer IR and distinguished distinct RNA polymerase II (Pol II)‐ and Pol IV‐dependent pathways of siRNA biogenesis. At the original silencer locus, Pol‐II transcription of the IR from a 35S promoter produces a hairpin RNA that is diced into abundant siRNAs of 21–24 nt. A silencer variant lacking the 35S promoter revealed a normally masked Pol IV‐dependent pathway that produces low levels of 24‐nt siRNAs from the tandem repeats. Both pathways operate concurrently at the original silencer locus. siRNAs accrue only from specific regions of the enhancer and embedded tandem repeat. Analysis of these sequences and endogenous tandem repeats producing siRNAs revealed the preferential accumulation of siRNAs at GC‐rich regions containing methylated CG dinucleotides. In addition to supporting a correlation between base composition, DNA methylation and siRNA accumulation, our results highlight the complexity of siRNA biogenesis at repetitive loci and show that Pol II and Pol IV use different promoters to transcribe the same template.
Perceived barriers among physicians for stopping non–cost‐effective blood‐saving measures in total hip and total knee arthroplasties
Authors: Voorn Veronique M.A. , Marang‐van de Mheen Perla J. , Wentink Manon M. , Kaptein Ad A. , Koopman‐van Gemert Ankie W.M.M. , So‐Osman Cynthia , Vliet Vlieland Thea P.M. , Nelissen Rob G.H.H. , van Bodegom‐Vos Leti ,   LISBOA Study Group
Published: May 2014

BackgroundDespite evidence that the blood‐saving measures (BSMs) erythropoietin (EPO) and intra‐ and postoperative blood salvage are not (cost‐)effective in primary elective total hip and knee arthroplasties, they are used frequently in Dutch hospitals. This study aims to assess the impact of barriers associated with the intention of physicians to stop BSMs.Study Design and MethodsA survey among 400 orthopedic surgeons and 400 anesthesiologists within the Netherlands was performed. Multivariate logistic regression was used to identify barriers associated with intention to stop BSMs.ResultsA total of 153 (40%) orthopedic surgeons and 100 (27%) anesthesiologists responded. Of all responders 67% used EPO, perioperative blood salvage, or a combination. After reading the evidence on non–cost‐effective BSMs, 50% of respondents intended to stop EPO and 53% to stop perioperative blood salvage. In general, barriers perceived most frequently were lack of attention for blood management (90% of respondents), department priority to prevent transfusions (88%), and patient characteristics such as comorbidity (81%). Barriers significantly associated with intention to stop EPO were lack of interest to save money and the impact of other involved parties. Barriers significantly associated with intention to stop perioperative blood salvage were concerns about patient safety, lack of alternatives, losing experience with the technique, and lack of interest to save money.ConclusionPhysicians experience barriers to stop using BSMs, related to their own technical skills, patient safety, current blood management policy, and lack of interest to save money. These barriers should be targeted in strategies to make BSM use cost‐effective.
Immunologic characterization suggests reduced alloimmunization in a murine model of thalassemia intermedia
Authors: Bao Weili , Zhong Hui , Yazdanbakhsh Karina 
Published: May 2014

BackgroundTransfusion therapy remains a mainstay of treatment for patients with thalassemia major and to a lesser extent for the less anemic patients with thalassemia intermedia. We have previously reported a role for regulatory T cells (Tregs) in the control of antibody responses in wild‐type C57BL/6 (WT) mice exposed to allogeneic red blood cell transfusions. As an initial step to study and characterize immune regulation in thalassemias, we performed an immunologic cell–type characterization of C57BL/6 Hbbth‐1/Hbbth‐1 mouse model of thalassemia intermedia (Thal) in steady state as well as after transfusions with allogeneic blood.Study Design and MethodsThe myeloid and lymphocyte compartments including Tregs and T helper (Th) responses were analyzed in transfusion naive Thal and WT mouse spleens. The effect of allogeneic transfusions on Treg and global T helper responses was also measured.ResultsWe found elevated levels and activity of splenic Tregs in Thal mice with lower Th type 1/Th type 2 ratios before as well as after transfusion. Furthermore, pretransfused Thal mice had altered ratios of the splenic myeloid compartment with increased proportion of macrophages but lower frequency of conventional dendritic cells. Surprisingly, transfusions resulted in lower alloimmunization levels in Thal compared to WT mice.ConclusionThese data suggest that this experimental model of thalassemia intermedia has an intrinsic alteration in splenic immunoregulation with an increased resistance to alloimmunization, raising the possibility that studying this animal model may help to identify potential immunoregulatory networks to inhibit alloimmunization.
Specific Pathogen‐Free Pig Herds also Free from Campylobacter?
Authors: Kolstoe E. M. , Iversen T. , Østensvik Ø. , Abdelghani A. , Secic I. , Nesbakken T. 
Published: May 2014

SummaryAs Specific Pathogen‐Free (SPF) pig herds are designed and managed to prevent specific pig diseases, it might be feasible to expand the list of micro‐organisms also including zoonotic pathogens such as Campylobacter coli as this agent has its origin in pigs. In a previous survey, 15 of 16 of SPF herds were found free from human pathogenic Yersinia enterocolitica. Accordingly, three nucleus and seven multiplying herds were surveyed for Campylobacter to investigate whether the Norwegian SPF pig pyramid also might be free from this agent. In conclusion, the intervention of Campylobacter at the herd level might be possible as four of 10 SPF herds tested negative in two sets of samples from both autumn 2008 and summer/early autumn 2010. The four negative herds were all located in remote areas several kilometres away from conventional pig farming while the positive SPF farms were all situated in neighbourhoods with conventional pig production. It seems more difficult to control Campylobacter than some specific animal disease agents and another significant zoonotic agent, Y. enterocolitica, in pig herds.
The impact of prepolarization on Earth’s field laboratory nuclear-magnetic-resonance relaxation experiments
Authors: Walbrecker Jan O. , Knight Rosemary , Grunewald Elliot 
Published: May 2014

To advance our understanding, and the application of surface nuclear magnetic resonance (NMR), we need to conduct Earth’s magnetic field (EF) laboratory NMR measurements of the acquired relaxation times. In EF laboratory NMR, prepolarization is used to achieve detectable signal levels. This involves exposing the sample to a static magnetic field to increase the equilibrium magnetization associated with the nuclear spins of protons in the pore fluid. We found that prepolarization can also have a significant impact on the commonly measured relaxation time [Formula: see text]. We studied this impact on [Formula: see text] using a set of sand samples taken from boreholes in the U.S. High Plains aquifer. Using rock-magnetic measurements, we found that prepolarization at 25 mT increased the magnetization of the solid phase of the samples up to a factor of 10. For these samples, we observed [Formula: see text] that decreased from 30 to 3 ms with increasing magnetization. Surface NMR data collected at the borehole site indicate significantly longer [Formula: see text] (50–80 ms) at the depths from which the samples were taken. We attributed our observations to prepolarization inducing remanent magnetization in the solid phase of the sample, which results in elevated internal magnetic fields that reduce [Formula: see text]. In contrast, we found good agreement between EF laboratory and surface NMR measurements of the relaxation time [Formula: see text]. Because [Formula: see text] is unaffected by internal fields, this supports our conclusion that prepolarization is significantly impacting the laboratory measurement of [Formula: see text]. To mitigate these undesired effects, we have developed the inclusion of a demagnetization pulse after prepolarization in EF laboratory experiments. By applying the demagnetization pulse along the same direction of the static field only the remanent magnetization of the solid phase of the sample would be removed, whereas the prepolarized state of the nuclear spin magnetization of the liquid phase would be retained.
Assessment of body composition using bioelectrical impedance in patients with schizophrenia – preliminary report
Authors: Wysokiński Adam , Kłoszewska Iwona 
Published: May 2014

Aim of the studyMetabolic syndrome is found in ~40% of patients treated with antipsychotics and abdominal obesity plays a crucial role in its development. The aim of this study is to evaluate body composition in subjects with schizophrenia treated with antipsychotics.Subject or material and methodsAnthropometric (BMI, abdominal, waist, leg and hip circumferences), laboratory (glucose, lipid profile) and body composition (body fat, lean mass, body water) were measured in 77 patients with schizophrenia treated with antipsychotics.ResultsCentral obesity in women was found in >90% and was more frequent comparing to men (p = 0.04). Incidence of dyslipidemia (~80%) and abnormal body weight (~70%) was also high, while impaired level of blood glucose was less frequent (~25%). Women had more body fat (39.2±1.4 vs. 27.7±1.3, p <0.001) and less lean mass and body water. Amounts of excessive body weight and fat were higher in women (13.4±2.1 vs. 8.2±1.5, p = 0.02 and 7.9±1.3 vs. 3.2±1.2, p = 0.008). Percentages of women with weight and body fat exceeding target maximums were higher (96.4% vs. 79.6%, p = 0.04 and 89.3% vs. 67.3%, p = 0.03).DiscussionTreatment with antipsychotics is associated with severe metabolic side-effects. High frequency of abdominal obesity, excessive weight and increased amount of total body fat make women more susceptible to cardiovascular events, thus carefully monitored is required. Assessment of body composition using BIA is an easy and quick method of improving daily psychiatric care.ConclusionsPatients treated with antipsychotics require careful monitoring using available algorithms.
On Theoretical and Empirical Aspects of Marginal Distribution Choice Models
Authors: Mishra Vinit Kumar , Natarajan Karthik , Padmanabhan Dhanesh , Teo Chung-Piaw , Li Xiaobo 
Published: May 2014

In this paper, we study the properties of a recently proposed class of semiparametric discrete choice models (referred to as the marginal distribution model (MDM)), by optimizing over a family of joint error distributions with prescribed marginal distributions. Surprisingly, the choice probabilities arising from the family of generalized extreme value models of which the multinomial logit model is a special case can be obtained from this approach, despite the difference in assumptions on the underlying probability distributions. We use this connection to develop flexible and general choice models to incorporate consumer and product level heterogeneity in both partworths and scale parameters in the choice model. Furthermore, the extremal distributions obtained from the MDM can be used to approximate the Fisher's information matrix to obtain reliable standard error estimates of the partworth parameters, without having to bootstrap the method. We use simulated and empirical data sets to test the performance of this approach. We evaluate the performance against the classical multinomial logit, mixed logit, and a machine learning approach that accounts for partworth heterogeneity. Our numerical results indicate that MDM provides a practical semiparametric alternative to choice modeling.This paper was accepted by Eric Bradlow, special issue on business analytics.
An Empirical Analysis of Digital Music Bundling Strategies
Authors: Danaher Brett , Huang Yan , Smith Michael D. , Telang Rahul 
Published: May 2014

We use panel data on digital song and album sales coupled with a quasi-random price experiment to determine own- and cross-price elasticities for songs and albums. We then develop a structural model of consumer demand to estimate welfare under various policy relevant counterfactual scenarios. This approach represents an early application of the “big data” management paradigm within the media industries and provides managers with detailed guidance on optimal pricing and marketing strategies for digital music. Our results show that tiered pricing coupled with reduced album pricing increases revenue to the labels by 18% relative to uniform pricing policies traditionally preferred by digital marketplaces while also increasing consumer surplus by 23%. Thus, optimal tiered pricing can yield a Pareto improvement over the prior status quo. Additionally, our results indicate that even without tiered pricing, unbundling albums outperforms “album-only” pricing policies that dominated the era of physical CD/cassette sales. This paper was accepted by Alok Gupta, special issue on business analytics.
The Evolution of Compact Binary Star Systems
Authors: Postnov Konstantin A. , Yungelson Lev R. 
Published: May 2014

AbstractWe review the formation and evolution of compact binary stars consisting of white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Mergings of compact-star binaries are expected to be the most important sources for forthcoming gravitational-wave (GW) astronomy. In the first part of the review, we discuss observational manifestations of close binaries with NS and/or BH components and their merger rate, crucial points in the formation and evolution of compact stars in binary systems, including the treatment of the natal kicks, which NSs and BHs acquire during the core collapse of massive stars and the common envelope phase of binary evolution, which are most relevant to the merging rates of NS-NS, NS-BH and BH-BH binaries. The second part of the review is devoted mainly to the formation and evolution of binary WDs and their observational manifestations, including their role as progenitors of cosmologically-important thermonuclear SN Ia. We also consider AM CVn-stars, which are thought to be the best verification binary GW sources for future low-frequency GW space interferometers.
Descolonizar la educación desde la crianza
Authors: Contreras Salinas Sylvia , Ramírez Pavelic Mónica 
Published: May 2014

Recibido 10 de setiembre de 2013 • Corregido 28 de enero de 2014 • Aceptado 2 de abril de 2014
Este ensayo busca problematizar algunas transformaciones que se imponen a la educación en la actualidad, en el marco de los debates de deconstrucción de la educación colonizadora versus una educación definida como crianza. Crianza que, desde la perspectiva del diálogo de saberes y la práctica “otra” que implica la interculturalidad, retoma una educación que se desarrolla en múltiples espacios, en una expansión del saber gestado en la experiencia cotidiana, social, histórica y personal de las comunidades. Desde esta premisa, el presente texto ha sido construido con hilos discursivos, destacándose las palabras de Juan, un campesino de la zona central de Chile; pues desde la proposición foucaultiana, la fuerza y el sentido de los discursos estaría dado por las posiciones de poder; por ello, se apuesta a poner en circulación el pensamiento de un ser humano situado, inmerso en el cotidiano mundo de lo biótico.
Pedagogía saludable: Despertar de un nuevo nodo
Authors: Castillo Cedeño Ileana , Castillo Cedeño Rocío , Flores Davis Luz Emilia , Miranda Cervantes Giselle 
Published: May 2014

Recibido 6 de noviembre de 2013 • Corregido 22 de febrero de 2014 • Aceptado 2 de abril de 2014
Este escrito pretende recuperar la visión de pedagogía en la vida, en tanto experiencia y proceso que dignifica la alegría, el amor, la ecología, el ocio, la libertad y la esperanza, como opciones que posibilitan rutas para un trabajo pedagógico que genere salud. El posicionamiento teórico se asume desde un paradigma holístico para concluir que la crisis planetaria que genera grandes y persistentes problemas de salud: personales, sociales y planetarios; es posible de pugnar, desde una pedagogía saludable, la cual constituye un desafío creativo, amoroso y esperanzador para la convivencia de las diversas formas de vida. El término pedagogía saludable surge así de la necesidad de establecer una relación dialógica entre pedagogía y salud, a partir de visiones renovadas que conlleven al surgimiento de un nuevo nodo. El derecho a la salud y el derecho a la educación se asumen generalmente de manera independiente uno del otro. No obstante, la intersección entre ambos puede significar un gran reto y una importante revelación.
Implementación del aprendizaje colaborativo durante el Laboratorio de Cálculos Farmacéuticos Aplicados en la Facultad de Farmacia de la Universidad de Costa Rica
Authors: Mora Román Juan José 
Published: May 2014

Recibido 16 de setiembre de 2013 • Corregido 31 de enero de 2014 • Aceptado 9 de abril de 2014 En la actualidad, existe un problema en la Facultad de Farmacia referente a la existencia de poca o nula comunicación entre el estudiantado en un mismo curso o nivel académico. El aprendizaje colaborativo es una estrategia metodológica que va más allá de un simple trabajo en grupo, debido a que se forman equipos pequeños que, luego de haber recibido las indicaciones del personal docente, intercambian conocimiento y trabajan en una asignación hasta que todas las personas que conforman el grupo la han comprendido y finalizado, aprendiendo mediante la colaboración. Los elementos principales de este aprendizaje incluyen: el diseño intencional, mediante la estructuración de actividades por parte del personal académico, la colaboración a través de un compromiso activo de todas las personas del grupo de trabajo y la enseñanza significativa mediante el incremento y la profundización de los conocimientos individuales y colectivos en relación con un determinado tema. Por esta razón, se realizó esta experiencia didáctica durante tres sesiones del Laboratorio de Cálculos Farmacéuticos Aplicados (FA-2023) en el segundo semestre de 2012. En ellas, los grupos de estudiantes se dividieron en parejas y se les asignaron tareas particulares que debían ser cumplidas antes, durante y después de cada sesión de laboratorio. Para determinar el resultado de la estrategia empleada, se observaron las calificaciones obtenidas por parte de la totalidad de los grupos (24 estudiantes) en los exámenes cortos y los reportes de dichas sesiones, y se compararon frente a las calificaciones obtenidas en ambos rubros en las sesiones en las cuales no se usó el aprendizaje colaborativo. También, se empleó la encuesta, específicamente un cuestionario, para conocer la opinión estudiantil con respecto a esta estrategia metodológica. Para el análisis de los datos, se llevó a cabo un análisis sociodemográfico para la edad y el sexo, y un análisis descriptivo con distribución de frecuencias para el resto de las preguntas del cuestionario. Los resultados obtenidos muestran una experiencia muy enriquecedora tanto desde la perspectiva docente como del estudiantado. Por ello, es necesaria y recomendable la implementación de esta estrategia para los procesos de formación en todos los niveles de educación en el país.
What drives microplate motion and deformation in the northeastern Caribbean plate boundary region?
Authors: van Benthem Steven , Govers Rob , Wortel Rinus 
Published: May 2014

AbstractThe north Caribbean plate boundary zone is a broad deformation zone with several fault systems and tectonic blocks that move with different velocities. The indentation by the Bahamas Platform (the “Bahamas Collision”) is generally invoked as a cause of this fragmentation. We propose that a second driver of deformation is the western edge of the south dipping Puerto Rico slab moving sideways with the North America plate. The westward motion of the slab edge results in a push on the Caribbean plate farther west. We refer to this second mechanism for deformation as “Slab Edge Push.” The motion of the North America plate relative to the Caribbean plate causes both drivers to migrate from east to west. The Bahamas Collision and Slab Edge Push have been operating simultaneously since the Miocene. The question is the relative importance of the two mechanisms. We use mechanical finite element models that represent the two mechanisms from the late Oligocene (30 Ma) to the present. For the present, both models successfully reproduce observed deformation, implying that both models are viable. Back in time the Slab Edge Push mechanism better reproduces observations. Neither mechanism successfully reproduces the observed Miocene counterclockwise rotation of Puerto Rico. We use this rotation to tune a final model that includes fractional contributions of both mechanisms. We find that the Slab Edge Push was the dominant driver of deformation in the north Caribbean plate boundary zone since 30 Ma.
The association between cardiovascular risk factors and high blood pressure in adolescents: A school‐based study
Authors: Christofaro Diego G.D. , Fernandes Rômulo A. , Oliveira Arli R. , Freitas Júnior Ismael Forte , Barros Mauro V.G. , Ritti‐Dias Raphael M. 
Published: May 2014

ABSTRACTObjectiveAlthough previous studies have analyzed the association between cardiovascular risk factors and blood pressure in adolescents, few studies conducted in developing countries analyzed whether the aggregation of risk factors contributes to an increased risk of high blood pressure in adolescents. The objective of this study was to assess the association between cardiovascular risk factors (including general overweight, abdominal obesity, high consumption of foods rich in fats, and insufficient physical activity levels) and high blood pressure in adolescents.MethodsThis study was carried out from 2007 to 2008 with 1021 adolescents (528 girls) from primary schools located in the city of Londrina‐ Brazil. Blood pressure was assessed using an oscillometric device. General overweight was obtained through body mass index, abdominal obesity was assessed using waist circumference, and the consumption of foods rich in fat and physical activity were assessed using a questionnaire. The sum of these risk factors was determined.ResultsAdolescents with three or four aggregated risk factors were more likely to have higher values of systolic and diastolic blood pressure when compared with adolescents who did not have any cardiovascular risk factors (P = 0.001 for both). Logistic regression indicated that groups of adolescents with 2 (OR= 2.46 [1.11–5.42]; P = 0.026), 3 (OR= 4.97 [2.07–11.92]; P = 0.001) or 4 risk factors (OR= 6.79 [2.24–19.9]; P = 0.001) presented an increased likelihood of high blood pressure.ConclusionsThe number of cardiovascular risk factors was found to be related to high blood pressure in adolescents. Am. J. Hum. Biol. 26:518–522, 2014. © 2014 Wiley Periodicals, Inc.