bluuebunny/crossref_metadata_2025 huggingface dataset:
“No vine para acompañarme, vine para trabajar.” O cómo las mujeres centroamericanas organizan sus hogares transnacionales en Belice City
Authors: Winters Nanneke
Published: October 2010

A pesar del creciente interés que ha suscitado el estudio de los procesos de migración internacional desde una perspectiva de género, la mayoría de los estudios solamente describe la migración de hombres y mujeres por separado sin tener en cuenta sus interacciones, o reflexiona sobre la cuestión del empoderamiento de la mujer a través de la migración. Sin embargo, la transformación de familias, hogares y comunidades derivada de la migración es mucho más compleja y requiere de un enfoque relacional más detallado y profundo. En este artículo intento contribuir al estudio de este tema a través del análisis de un componente fundamental de la migración internacional, que es la organización de hogares transnacionales. Con objeto de poder aplicar una perspectiva de género en el análisis de la organización de hogares transnacionales, aplicaré el marco teórico gendered geographies of power desarrollado por Sarah Mahler y Patricia Pessar. El presente estudio está basado en un trabajo de campo sobre las diferentes estrategias que utilizan las mujeres (y hombres) centroamericanos que emigran a Belice City para ‘salir adelante'. Sus historias muestran cómo las mujeres migrantes intentan utilizar su condición de mujer transnacional a su favor. A partir de sus experiencias y perspectivas, argumento que el discurso mundial de la migración internacional necesita de un replanteamiento que tome en cuenta la interacción de hombres y mujeres y las geometrías de poder en que se encuentran los migrantes.Palabras clave: migración / hogares transnacionales / género / Centroamérica / BeliceDOI: 10.5377/encuentro.v41i84.47Encuentro 2009/ Año XLI, N° 84. 6-20
Uso de Internet del estudiantado de la Universidad Centroamericana, con enfoque en las redes sociales
Authors: Rodrigues Renata , Flores Amaru Canales , Peña Tatiana , Castro Gabriela , Reyes Grettel
Published: October 2010

El artículo presenta los resultados de un estudio sobre los usos de Internet que hace el estudiantado de la UCA, enfocándose en los hábitos de participación en las redes sociales existentes en línea. Fue realizado en el primer cuatrimestre de 2009 con un universo de aproximadamente siete mil estudiantes de las veinte carreras de Pregrado. Se aplicó una encuesta que indagaba sobre lugar y frecuencia de acceso a Internet, tipo de uso de la red, conocimiento y uso de las redes sociales y sus políticas de uso. Los principales resultados muestran que los estudiantes utilizan la Internet con mucha frecuencia y la principal actividad es la búsqueda de información. Otras actividades importantes están enfocadas a la comunicación con amigos a través del correo electrónico y el chat, y el entretenimiento a través de descarga de música, películas y juegos en línea. Dos terceras partes de los estudiantes participan como miembros de redes sociales, siendo Facebook y Hi5 las preferidas. La mayoría desconoce las políticas de uso de estas redes.DOI: 10.5377/encuentro.v41i84.49Encuentro 2009/ Año XLI, N° 84, 44-61
Tendencias actuales de la investigación genómica. Sus perspectivas en Nicaragua
Authors: Huete-Pérez Jorge A
Published: October 2010

DOI: 10.5377/encuentro.v41i84.52Encuentro 2009/ Año XLI, N° 84, 87-93
Caracterización de la enfermedad de Alzheimer en Nicaragua mediante parámetros clínicos, moleculares y de imagen
Authors: Zepeda Eddy
Published: October 2010

DOI: 10.5377/encuentro.v41i84.53Encuentro 2009/ Año XLI, N° 84, 94-98
Informe de participación en la Third International Barcode of life Conference, México DF, del 7 al 13 de noviembre de 2009
Authors: Medina Lucía Páiz
Published: October 2010

DOI: 10.5377/encuentro.v41i84.55Encuentro 2009/ Año XLI, N° 84, 102-104
Determinantes en la elección del tipo de combustible para cocción de alimentos en asentamientos humanos
Authors: Meza Carlos , Narváez Carlos
Published: October 2010

El artículo presenta los determinantes en la elección del tipo de combustible primario para cocción de alimentos en cuatro asentamientos humanos urbanos localizados en los departamentos de Managua y León. Se eligió un modelo logístico binario (Logit) que permitió concluir que los factores que inciden en la elección son: el ingreso, los niveles de educación, el departamento al que pertenecen los barrios, número de miembros del hogar y la edad del cabeza de familia. Este estudio ofrece un punto de inicio en la discusión de los aspectos de relevancia en la demanda de combustibles a nivel urbano en Managua y León.
Actitudes de alumnos de posgrado hacia la estadística aplicada a la investigación
Authors: Gómez Eduardo Escalante
Published: October 2010

En esta investigación se examina si existen cambios de actitudes en los alumnos de posgrado que participan en un módulo de estadística aplicado a la investigación. El autor investigó si los alumnos desarrollaron actitudes más positivas hacia la estadística después del desarrollo del módulo, que implicó una estrategia didáctica específica. Los resultados revelan que el desarrollo de las actividades que permiten el diseño de configuraciones didácticas, trayectorias didácticas, trayectorias epistémicas y trayectorias de mediación, teniendo como eje central la construcción del conocimiento estadístico por los propios alumnos, genera aprendizajes más significativos y actitudes más positivas hacia la estadística. Estas conclusiones tienen implicaciones importantes para preparar a los alumnos de posgrado en la elaboración de sus tesis o investigaciones.
La financiación de las Regiones Autónomas de la Costa Atlántica de Nicaragua mediante recargos
Authors: Morales Héctor Zacarías Méndez
Published: October 2010

La indiscutible diferencia histórica, cultural y social entre la población del Caribe y el resto del país ha significado un óbice para la integración social y económica de los ciudadanos en el progreso material de la nación, así como conflictos y discordias para ambos sectores territoriales. Esta situación condujo en 1987 al reconocimiento de un régimen de autonomía regional que garantice y respete el ejercicio efectivo de los derechos de las comunidades de la Costa Atlántica, consignados en nuestra Constitución Política.El precepto surgido dos décadas atrás perfiló la concreción de los derechos humanos, culturales, económicos, sociales y políticos de casi el 10% de la población. El interés decayó con el transcurso de los años por parte de los gobiernos de turno, surgiendo una serie de circunstancias que entorpecen una real autonomía territorial jurídicamente reconocida, así como una autonomía financiera regional que garantice un autogobierno responsable, de competencias públicas, y en su territorio, capaz de sufragar sus gastos y perseguir los fines del Estado Social de Derecho.Es por ello que urge la búsqueda y consecución de fuentes de ingreso para las regiones del Caribe nicaragüense que proporcionen la suficiencia financiera de los gobiernos regionales en aras de afianzar su autonomía, cumplir los preceptos constitucionales y derechos fundamentales que demandan el desarrollo integral de la región, y que permita la plena inclusión de la población nicaragüense del Caribe en el tejido social y económico de una nación llamada a conformar un Estado social de Derecho unitario e indivisible.
Reflexiones sobre la filosofía del Dr. Alejandro Serrano a través del segundo tomo de su obra
Authors: Arríen Juan Bautista
Published: October 2010

Desde diferentes plataformas, Alejandro ha ido armando un pensamiento sólido, coherente, flexible, creador y sobre todo comprometido con la realidad que desafía al ser humano en sus múltiples acciones y manifestaciones humanas, sociales, históricas, políticas, éticas y culturales. Todo ello, “con la voluntad que anida al ser humano de continuar buscando las respuestas a las interminables preguntas por los seres y el mundo y la fe que no deja desfallecer la esperanza de construir la verdad, aceptando que la filosofía debe buscar la parte de la verdad que se manifiesta en cada tiempo histórico, porque la verdad no es más que el proceso de construir la verdad sólo posible al insertarse y reinventarse el hombre en la historia”.
Limitación del reclutamiento de plantas
Authors: Ruiz Javier
Published: October 2010

Tengo mucho agrado en presentar a la comunidad científica nacional mi más reciente libro titulado: Plant Recruitment Limitation, traducido al español como: Limitación del Reclutamiento de Plantas
Estimación de la demanda y el costo de no tener agua potable en Nicaragua, tomando como base las diferentes alternativas de abastecimiento (puestos, ríos, manantiales, pipas, carretas y pozos)
Authors: Narváez Carlos , Meza Carlos
Published: October 2010

El estudio estima la demanda de agua de las viviendas que no cuentan con el servicio de agua potable por medio de tubería. La estimación se realiza utilizando la Encuesta de Medición de Nivel de Vida (INIDE, 2005a), donde se presenta información sobre las formas de abastecimiento de agua, el tiempo dedicado a la recolección, el costo monetario por galón, entre otras variables socioeconómicas. Se eligió el modelo teórico basado en el enfoque de producción de hogares propuesto por Bockstael y McConnell (1983) que permite estimar el excedente del consumidor como medida de beneficios potenciales del hogar por contar con agua potable dentro de sus viviendas.Los beneficios estimados se calcularon tomando en cuenta el costo de oportunidad en el tiempo dado a un proceso de búsqueda de agua por parte del hogar más el pago por el bien en las diferentes alternativas (puestos, ríos, manantiales, pipas, carretas y pozos).La investigación mira desde otra perspectiva el modelo de costo de viaje usado comúnmente en estudios de recreación ambiental y pone a disposición de los evaluadores de proyectos una herramienta alternativa de la estimación de beneficios en proyectos de abastecimiento de agua.Las personas sin acceso al agua pagan 316 córdobas por mes (C$/Mes) y consumen aproximadamente 2 metros cúbicos mensuales. Un cliente con servicio de agua por medio de la red de ENACAL con un consumo de 15 metros cúbicos paga por cargo de agua potable 72.75 C$/Mes. Es importante mencionar que existen otros cargos como alcantarillado sanitario y cargo fijo que deben sumarse al cargo de agua potable en una factura correspondiente a viviendas en los departamentos en donde el problema de falta de agua es mayor. Por tanto, el mismo consumo (15 M3/Mes) por vivienda -si incluimos todos los cargos- pagaría 98.75 C$/Mes. El cargo de agua potable para consumos de 30 M3/Mes es igual a 168 C$, una cifra mucho menor a lo que pagan las personas que no cuenta con el servicio. Los datos obtenidos se basan en el pliego tarifario actual.
Diagnóstico Territorial Integral del municipio de Ciudad Darío
Authors: Dietsch Laurent , Novoa Edwin
Published: October 2010

En este artículo se presenta el "diagnóstico territorial integral de Ciudad Darío" realizado como trabajo de fin de curso de la Maestría en Desarrollo Rural de la Universidad Centroamericana. Este estudio ha buscado contribuir a la formulación de propuestas de intervención de los actores sociales del municipio de Ciudad Darío sobre los procesos estratégicos de desarrollo del territorio. Se realizó una zonificación integral del municipio, identificándose cuatro zonas: una zona alta, campesina de agricultura de subsistencia; una zona de laderas secas; una planicie seca de latifundio ganadero; y finalmente, una zona de llanos y vegas fértiles de riego semi-intensivo. Posteriormente, se identificaron y clasificaron por capital (ambiental, económico, social-humano y político-institucional) y nivel territorial, los principales procesos de cambio que afectan o podrían afectar al municipio. Su análisis permitió caracterizar las principales oportunidades y amenazas para el desarrollo del territorio y, al relacionarlo con las fortalezas y debilidades identificadas en la zonificación, evidenciar los principales factores que podrían incidir en el municipio y sus principales retos. Para enfrentar estos retos, se identificaron tres ejes estratégicos: la reducción de los niveles de inseguridad alimentaria y vulnerabilidad ambiental del municipio; el fomento integral de las cadenas de producción de hortalizas; y la prevención de riesgos sociales. Para cada uno de estos ejes se ha definido un conjunto de acciones ordenadas por capital y nivel territorial, orientadas a incidir sobre los principales procesos de cambio identificados. Finalmente, se definieron ejes estratégicos transversales enfocados al desarrollo de capacidades de incidir sobre los procesos claves de desarrollo del municipio.
Sobre "Sandino. Una biografía política" de Volker Wünderich
Authors: Rocha José Luis
Published: October 2010

Imagino a Volker en la Nicaragua de los 80, una Nicaragua por la que las dos Alemanias –Federal y Democrática– estaban apostando tanto. Lo imagino recorriendo las candentes calles de Managua, holgadas para el parque vehicular de aquellos días, aunque no tanto para algunas pintorescas donaciones alemanas: los temibles IFAs1 –a cuyas siglas fue jocosamente reasignado el significado “Imposible Frenar A tiempo”– y aquella gigantesca cocina mecánica –quizás Volker se topó con ese armatoste verde olivo sin saber– que en cuestión de minutos podía preparar 500 huevos revueltos, arroz para dos batallones y, si la operaba el ingenio de la mano de la temeridad, un gallo pinto en tiempo y forma para halagar el paladar vernáculo
Dental Prosthetic Status and Prosthetic Need of the Institutionalized Elderly Living in Geriatric Homes in Mangalore: A Pilot Study
Authors: Shenoy Rekha P. , Hegde Vijaya
Published: October 2010

Introduction. To promote oral health among the elderly, we need to know their prosthetic status and prosthetic need. Hence, a survey of prosthetic status and need of elderly inmates of old age homes in Mangalore was done. Materials and Methods. A cross-sectional study was undertaken, and 133 subjects aged 60 years and above were examined (54.9% males and 45.1% females). Results. Eighty-eight percent of those examined were fully edentulous, and only 12% had complete dentures; none of the study subjects had partial dentures. Prosthetic status was significantly associated with gender (P=.024), while prosthetic need and gender were not significantly associated (P=.395). Conclusions. A high unmet need for prosthetic care existed among the institutionalized elderly surveyed.
A Method for Preparing Primary Retinal Cell Cultures for Evaluating the Neuroprotective and Neuritogenic Effect of Factors on Axotomized Mature CNS Neurons
Authors: Grozdanov Veselin , Müller Adrienne , Sengottuvel Vetrivel , Leibinger Marco , Fischer Dietmar
Published: October 2010

Retinal ganglion cells (RGCs) are central nervous system neurons with a very limited ability for axon regeneration. This unit details a cell culture technique, which can be used to functionally screen factors/compounds for their neuritogenic and neuroprotective effects on RGCs. In this protocol, the retina is isolated, digested in a papain solution, and after trituration, the RGCs are cultured. The neuritogenic effect of applied factors/compounds on RGCs in the medium is functionally determined by measuring the average neurite length of βIII‐tubulin‐positive RGCs in culture after 3 days. This protocol takes 3 to 7 days to perform depending on the application to complete, and is suitable to reliably test pharmacological and genetic approaches for their axon growth‐promoting and neuroprotective potential on mature RGCs. Curr. Protoc. Neurosci. 53:3.22.1‐3.22.10. © 2010 by John Wiley & Sons, Inc.
Social Recognition Assay in the Rat
Authors: Mathiasen Joanne R. , DiCamillo Amy
Published: October 2010

Neuropsychiatric disorders encompass a broad patient population in a variety of disease states across all age groups and are often accompanied by deficits in short‐term/working memory. However, most preclinical models that allow for an assessment of cognitive enhancement do not provide robust behavioral readouts with a level of throughput sufficient to support modern drug discovery efforts. The rat social recognition assay presented in this unit is one exception that has been increasingly employed to test new chemical entities for enhancing cognitive activity. The test is simple in design and takes advantage of the spontaneous behavior of rats to investigate conspecifics. The protocol in this unit is designed to evaluate the effects of a test substance on the short‐term/working memory of adult male rats employing 30‐min or 2‐hr pretreatment times. Curr. Protoc. Neurosci. 53:8.51.1‐8.51.15. © 2010 by John Wiley & Sons, Inc.
Modeling Appetitive Pavlovian‐Instrumental Interactions in Mice
Authors: O'Connor Eoin C. , Stephens David N. , Crombag Hans S.
Published: October 2010

In appetitive Pavlovian associative learning, a stimulus (conditioned stimulus, CS) that has been associated with the delivery of a reinforcing event (unconditioned stimulus, US; e.g., food) can subsequently elicit or modulate goal‐directed instrumental behaviors. For example, a Pavlovian CS can serve to reinforce (novel) instrumental behavior (conditioned reinforcement or CRf), or it can energize and potentiate ongoing instrumental responses when presented non‐contingently (Pavlovian‐instrumental transfer or PIT). Notably, these different effects of a Pavlovian CS on instrumental behavior are mediated by dissociable psychological and neurobiological mechanisms. Given the critical role that Pavlovian‐instrumental interactions play in regulating motivated behavior and maladaptive manifestations of motivation such as eating disorders and addictions, understanding the underlying psychological and neurobiological mechanisms will be important. This unit describes behavioral protocols that produce robust and reliable PIT and CRf in mice and that open the door for future studies using transgenic approaches into the molecular mechanisms underlying associative learning and motivation.Curr. Protoc. Neurosci. 53:8.25.1‐8.25.27. © 2010 by John Wiley & Sons, Inc.
Drug‐Induced Sexual Dysfunction in Rats
Authors: Chan Johnny S.W. , Waldinger Marcel D. , Olivier Berend , Oosting Ronald. S.
Published: October 2010

This unit describes the testing of sexual behaviors of male Wistar rats. The described test enables the detection of stimulatory and inhibitory profiles of compounds. The test includes four training sessions to reach a stable sexual performance, followed by acute and/or chronic administration of drugs. The main quantifiable sexual behaviors are number of mounts (no vaginal penetration), intromissions (vaginal penetration), and ejaculations. By comparing the test compound to reference compound(s), sexual (side) effects can be determined. Curr. Protoc. Neurosci. 53:9.34.1‐9.34.11. © 2010 by John Wiley & Sons, Inc.
Evaluation and Purchase of Confocal Microscopes: Numerous Factors to Consider
Authors: Zucker Robert M. , Chua Michael
Published: October 2010

The purchase of a confocal microscope is a difficult decision. Many factors need to be considered, which include hardware, software, company, support, service, and price. These issues are discussed to help guide the purchasing process. Curr. Protoc. Cytom. 54:2.16.1‐2.16.12. © 2010 by John Wiley & Sons, Inc.
Titration of Fluorochrome‐Conjugated Antibodies for Labeling Cell Surface Markers on Live Cells
Authors: Hulspas Ruud
Published: October 2010

Nonspecific antibody binding is best eliminated by optimizing the amount and concentration of the antibody. An antibody titration assay should be applied to determine the antibody amount and concentration resulting in the highest signal of the positive population and the lowest signal of the negative population. While conventional antibody titration protocols focus on the concentration of the antibody, this protocol for antibody titration considers the antibody concentration, as well as the antibody amount. Thus, it is designed to find the optimal antibody concentration for labeling antigens expressed on the surface membrane of live cells, while nonspecific antibody binding is kept to a minimum. Curr. Protoc. Cytom. 54:6.29.1‐6.29.9. © 2010 by John Wiley & Sons, Inc.
Microsphere‐Based Flow Cytometry Protease Assays for Use in Protease Activity Detection and High‐Throughput Screening
Authors: Saunders Matthew J. , Edwards Bruce S. , Zhu Jingshu , Sklar Larry A. , Graves Steven W.
Published: October 2010

This protocol describes microsphere‐based protease assays for use in flow cytometry and high‐throughput screening. This platform measures a loss of fluorescence from the surface of a microsphere due to the cleavage of an attached fluorescent protease substrate by a suitable protease enzyme. The assay format can be adapted to any site or protein‐specific protease of interest and results can be measured in both real time and as endpoint fluorescence assays on a flow cytometer. Endpoint assays are easily adapted to microplate format for flow cytometry high‐throughput analysis and inhibitor screening. Curr. Protoc. Cytom. 54:13.12.1‐13.12.17. © 2010 by John Wiley & Sons, Inc.
Kaede‐Centrin1 Labeling of Mother and Daughter Centrosomes in Mammalian Neocortical Neural Progenitors
Authors: Imai Janice H. , Wang Xiaoqun , Shi Song‐Hai
Published: October 2010

The importance of the centrosome in regulating basic cellular processes and cell fate decisions has become increasingly evident from recent studies tracing the etiology of developmental disorders to mutations in genes encoding centrosomal proteins. This unit details a protocol for a fluorescence‐based pulse labeling of centrioles of neural progenitor cells in the developing neocortex of mice. In utero electroporation of Kaede‐Centrin1 followed by in utero or ex vivo photoconversion allows a direct monitoring of the inheritance of centrosomes containing centrioles of different ages in dividing neocortical neural progenitors (i.e., radial glial cells). This is achieved by combining the irreversible photoconversion capacity of the Kaede protein from green to red fluorescence with the faithful duplication of the centrosome during each cell cycle. After two mitotic divisions following photoconversion, mother centrosomes containing the original labeled centriole appear in both red and green fluorescence, and can be distinguished from daughter centrosomes which appear in green fluorescence only. This facilitates the study of the inheritance and behavior of the mother and daughter centrosomes in asymmetric cell divisions in the developing mammalian neocortex. Curr. Protoc. Stem Cell Biol. 15:5A.5.1‐5A.5.12. © 2010 by John Wiley & Sons, Inc.
High‐Throughput Assessment of Bacterial Growth Inhibition by Optical Density Measurements
Authors: Campbell Jennifer
Published: October 2010

The increasing incidence of antibiotic‐resistant bacterial infections both in hospitals and in the community intensifies the need for new antibacterial strategies and targets. Although high‐throughput screening against live bacteria allows rapid discovery of compounds with growth‐inhibitory activities, these efforts have failed to fill the pipeline with the anticipated antibacterial compounds because target identification is often onerous. Recently, a strategy was reported that employs a bacterial growth inhibition assay readout using optical density measurements on paired strains—both a wild‐type strain and a pathway‐null mutant—to find inhibitors of wild‐type bacterial growth that specifically target conditionally essential enzymes in the pathway of interest. Protocols are provided here for determining the robustness of an assay, screening in a high‐throughput format, and setting up dose‐response curves in paired Staphylococcus aureus strains. However, the protocols can be used to screen for growth‐inhibitory compounds in any bacterial strain of interest. Curr. Protoc. Chem. Biol. 2:195‐208 © 2010 by John Wiley & Sons, Inc.
Space use selectivity by chimpanzees and gorillas in an indoor–outdoor enclosure
Authors: Ross S.R. , Calcutt S. , Schapiro S.J. , Hau J.
Published: October 2010

Understanding the relationship between physical environments and nonhuman primate behavior is a key element for effective care and management in a range of settings. The physical features of the captive environment, including not only gross useable space but also environmental complexity, can have a significant influence on primate behavior and ultimately, animal welfare. But despite this connection, there remains relatively little conclusive data on how captive primates, especially great apes, use the spaces provided to them, especially in modern, indoor–outdoor enclosures that have become more prevalent in recent years. In this study, we used four years of detailed data on where 23 great apes (chimpanzees and gorillas) positioned themselves within a modern, indoor–outdoor zoo enclosure to determine not only how the apes utilized their space but also how access to outdoor areas affected their spatial selectivity. We found that both species used relatively little of their available space: chimpanzees and gorillas spent half their time in only 3.2 and 1.5% of their useable three‐dimensional space, respectively. Chimpanzees utilized the outdoor space more than gorillas, but access to the outdoors did not affect space selectivity in the indoor area for either species. Although both species of ape were highly selective in their space use, consideration should be given to the importance of providing the choice to locate in a variety of spaces, including outdoor areas. These data represent an extremely detailed account of space selectivity by great apes in an indoor–outdoor environment and have substantial implications for future facility design and captive primate management. Am. J. Primatol. 73:197–208, 2011. © 2010 Wiley‐Liss, Inc.
Inter‐unit contests within a provisioned troop of Sichuan snub‐nosed monkeys (Rhinopithecus roxellana) in the Qinling Mountains, China
Authors: Zhao Qing , Tan Chia L.
Published: October 2010

Numerical superiority does not always ensure victory in intergroup contests. Although group size is likely to determine the maximum resource holding potential (RHP) of a group, the realized RHP is the collective outcome of individual group members' choices about participation in any given contest. For any group member, the choice about participation should be based on the assessment of costs and benefits that are affected by both ecological and social factors. In this study, we studied inter‐unit contests in a provisioned troop of Sichuan snub‐nosed monkeys (Rhinopithecus roxellana). We spent 368 hr in contact with 9 one‐male units sharing the same home range, during which we recorded 148 inter‐unit contests at a provisioning site. Inter‐unit contests always started as inter‐individual contests. Contests escalated only when the two individuals were of different age‐sex classes and one was an adult male. When a contest escalated, additional individuals were likely to get involved, and the outcome of the contest depended on unit members' choices about participation. The superiority in the number of participants rather than the superiority in unit size led to victory in inter‐unit contests, given that the difference in unit size did not predict a difference in the number of participants. Unit members were more likely to support others in inter‐unit contests in winter when food was sparse than in spring when food was abundant. In addition, unit members were more likely to support others in escalated contests than in those resulting in displacement, indicating that they tended to alter the outcome of a contest to gain immediate benefit. Although males initiated most inter‐unit contests, a clear win–loss was most likely when females joined the fight. This sex difference may reflect the benefits to males vs. females of living in a multi‐level society. Am. J. Primatol. 73:262–269, 2011. © 2010 Wiley‐Liss, Inc.
Impact of injection‐molding processing parameters on the electrical, mechanical, and thermal properties of thermoplastic/carbon nanotube nanocomposites
Authors: Rios P. F. , Ophir A. , Kenig S. , Efrati R. , Zonder L. , Popovitz‐Biro R.
Published: October 2010

Thermoplastic nanocomposites, based on high‐density polyethylene, polyamide 6, polyamide 66, poly(butylene terephthalate), or polycarbonate and containing multiwalled carbon nanotubes (CNTs), were compounded with either neat CNTs or commercial CNT master batches and injection‐molded for the evaluation of their electrical, mechanical, and thermal properties. The nanocomposites reached a percolation threshold within CNT concentrations of 2–5 wt %; however, the mechanical properties of the host polymers were affected. For some nanocomposites, better properties were achieved with neat CNTs, whereas for others, master batches were better. Then, polycarbonate and poly(butylene terephthalate), both with a CNT concentration of 3 wt %, were injection‐molded with a screening design of experiments (DOE) to evaluate the effects of the processing parameters on the properties of the nanocomposites. Although only a 10‐run screening DOE was performed, such effects were clearly observed. The volume resistivity was significantly dependent on the working temperature and varied up to 4 orders of magnitude. Other properties were also dependent on the processing parameters, albeit in a less pronounced fashion. Transmission electron microscopy indicated that conductive samples formed a percolation network, whereas nonconductive samples did not. In conclusion, injection‐molding parameters have a significant impact on the properties of polymer/CNT nanocomposites, and these parameters should be optimized to yield the best results. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Relating scratch resistance to injection molding‐induced morphology of polypropylene
Authors: Kobayashi Yutaka , Otsuki Yasuhiko , Kanno Hiroaki , Hanamoto Yasuhiro , Kanai Toshitaka
Published: October 2010

The relationship between the scratch resistance and the injection molding‐induced morphology of polypropylene (PP) was investigated. The crystal structure near the surface was controlled by the mold temperature and the doping of a nucleating agent (NA). Although α‐ and β‐NA were used to improve the scratch resistance of PP that was molded at a mold temperature of 40°C, both of the NAs only slightly affected the scratch resistance due to low crystallinity at the surface. When the mold temperature was increased, the skin layer became thin and a β‐form crystal formed. Plastic deformation under the scratch was limited in the frozen layer. Consequently, the thickness of the frozen layer (which had low crystallinity) had the predominant effect on the scratch resistance in comparison to the polymorphism differences. The crystal morphology was analyzed with synchrotron micro‐beam wide angle X‐ray diffraction and Fourier transform infrared spectroscopy. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Developing a Code of Conduct for whale shark interactions in Mozambique
Authors: Pierce Simon J. , Méndez‐Jiménez Adriana , Collins Kym , Rosero‐Caicedo Marcela , monadjem Ara
Published: October 2010

The whale shark (Rhincodon typus) is a popular focal species within the global marine tourism industry. Although this has contributed to increased protection being granted to the species in several countries, tourism itself can be detrimental to the sharks in the absence of appropriate management. Potential impacts can be mitigated, at least in the short term, by adherence to well‐designed interaction guidelines.

A burgeoning marine tourism industry based on swimming with whale sharks has developed at Tofo Beach in Mozambique. However, no formal management is currently in place at this site.

The behaviour of whale sharks during interactions with boats and swimmers were recorded during 137 commercial snorkelling trips run from Tofo Beach over a 20 month period. Whale sharks were encountered on 87% of trips, which operated year‐round.

Boat proximity and shark size were significant predictors of avoidance behaviour. No avoidance responses were recorded at >20 m boat distance.

The mean in‐water interaction time between sharks and swimmers was 8 min 48 s overall. There was a significant decrease in interaction times during encounters where sharks expressed avoidance behaviours, and also in cases where sharks had expressed boat avoidance behaviour before swimmers entered the water.

It is suggested that mean encounter times can be extended through adherence to a basic Code of Conduct for operators and swimmers that enforces minimum distances between the sharks, boats and swimmers. Using encounter time as a measure of the ‘success’ of interactions holds promise, as longer encounters appear to be indicative of lower impacts on sharks while also providing higher customer satisfaction for swimmers. Copyright © 2010 John Wiley & Sons, Ltd.
Comparative analyses of proteolytic activities in seven species of synanthropic acaridid mites
Authors: Erban Tomas , Hubert Jan
Published: October 2010

Microplate assays with 96 wells were optimized to screen proteolytic activities in mite homogenates. Whole‐mite extracts of Acarus siro, Aleuroglyphus ovatus, Tyrophagus putrescentiae, Tyroborus lini, Carpoglyphus lactis, Lepidoglyphus destructor, and Dermatophagoides farinae exhibited non‐specific proteolytic activity in buffers from pH 2 to 12, and three peaks of highest activity at pH 3, 5–6, and 10 were distinguished. The reducing agent Tris(2‐carboxyethyl)phosphine hydrochloride decreased general proteolytic activity on azocasein at pH 5 and 6. The results obtained on two non‐specific substrates, azocasein and azoalbumin, showed highly different ranks of the species at pH 5 and 6. Proteolytic activities toward Nα‐Benzoyl‐D,L‐arginine 4‐nitroanilide hydrochloride, N‐Succinyl‐L‐alanyl‐L‐alanyl‐L‐prolyl‐L‐phenylalanine 4‐nitroanilide, N‐Succinyl‐L‐alanyl‐L‐alanyl‐L‐alanine 4‐nitroanilide, Benzyloxycarbonyl‐L‐arginine‐L‐arginyl 4‐nitroanilide, and N‐Methoxysuccinyl‐L‐alanyl‐L‐alanyl‐L‐prolyl‐L‐methionine 4‐nitroanilide (MAAPMpNA) were highest at alkaline pH, but the activity toward MAAPMpNA was also high at pH 5 and 6. In contrast, N‐Succinyl‐L‐alanyl‐L‐alanyl‐L‐phenylalanine 4‐nitroanilide (AAPpNA) and L‐arginyl 4‐nitroanilide (ArgpNA) had the highest activity recorded at pH 6. The high activities observed on AAPpNA, ArgpNA, and MAAPMpNA at digestive pH suggest that enzymes present in these extracts could have the majority of proteolysis in the mite gut. Evidence of the presence of proteolytic activities on all tested substrates and in all the tested mite homogenates suggests that the proteolytic activities may contribute to allergenicity. Poor or undetected hydrolytic activities of mite extracts toward substrates for keratin and collagen at digestive pH underline the importance of ecological interactions between mites and microorganisms in the utilization of such substrates. © 2010 Wiley Periodicals, Inc.
Investigation of the Toxic Functional Group of Cephalosporins by Zebrafish Embryo Toxicity Test
Authors: Zhang Jingpu , Meng Jie , Li Yaping , Hu Changqin
Published: October 2010

2‐mercapto‐5‐methyl‐1,3,4‐thiadiazole (MMTD) is the 3'‐side chain of cephalosporin including cefazolin sodium (CFZL) and cefazedone (CFZD). It is not only present in finished products as the residual precursor, but also produced through drug degradation. Performing the zebrafish embryo toxicity test, we evaluated the toxicity effects of cefazolin sodium, cefazedone, their synthetic precursors and intermediates. Our results suggest that the teratogenic effect of cefazedone and cefazolin sodium on zebrafish embryonic development is associated with the structure of MMTD. They mainly interfere with the development of tissues and organs derived from embryonic ectoderm and mesoderm. We further consider the rationality of the quality control limit of MMTD (1.0%) in the specification. As the acceptable daily intakes (ADIs) of cefazolin is 10 µg/kg per day 16 and the minimum teratogenic concentration of MMTD is tenfold lower than that of cefazolin sodium, we recommend that the acceptable daily intakes of MMTD should be 1 µg/(kg day). In general, the therapeutic dose of cefazolin sodium is 2–4 g/day. Based upon the calculation of MMTD quality control limits (1.0%), MMTD intake can be 20–40 mg/day, which will be much more than the acceptable daily intake value of 1 µg/(kg day). Thus, MMTD should be recommended as a specified impurity and qualified as serious again.
Antinuclear antibody–positive patients should be grouped as a separate category in the classification of juvenile idiopathic arthritis
Authors: Ravelli Angelo , Varnier Giulia C. , Oliveira Sheila , Castell Esteban , Arguedas Olga , Magnani Alessandra , Pistorio Angela , Ruperto Nicolino , Magni‐Manzoni Silvia , Galasso Roberta , Lattanzi Bianca , Dalprà Sara , Battagliese Antonella , Verazza Sara , Allegra Maddalena , Martini Alberto
Published: October 2010

Objective

We undertook this study to test the hypothesis that in the International League of Associations for Rheumatology (ILAR) classification of juvenile idiopathic arthritis (JIA), patients with similar characteristics can be classified into different categories. We sought to investigate whether antinuclear antibody (ANA)–positive patients having disease in the ILAR categories of oligoarthritis, rheumatoid factor–negative polyarthritis, psoriatic arthritis, and undifferentiated arthritis share homogeneous features and to compare these features with those of ANA‐negative patients having the same categories of disease.

Methods

We identified JIA patients who had been followed up during a 22‐year period. ANA positivity was defined as ≥2 positive results at a titer of ≥1:160. Demographic and clinical features were recorded retrospectively and compared between ANA‐positive and ANA‐negative patients.

Results

Of a total of 971 patients, 711 were ANA positive, 149 were ANA negative, and 111 had an indeterminate ANA status. Patients with indeterminate ANA status were excluded. ANA‐positive patients in the different ILAR categories were similar in terms of age at disease presentation, female‐to‐male ratio, and frequency of asymmetric arthritis and iridocyclitis. Compared with ANA‐positive patients, the ANA‐negative group was older at disease presentation and had a lower prevalence of females, a lower frequency of iridocyclitis and asymmetric arthritis, a greater number of affected joints over time, and a different pattern of arthritis. The close relationship between the presence of ANAs and younger age at disease presentation, female predominance, asymmetric arthritis, development of iridocyclitis, lower number of affected joints over time, and lack of hip involvement was also confirmed by multivariate and multiple correspondence analysis.

Conclusion

Our findings substantiate the hypothesis that ANA‐positive patients classified into different JIA categories by current ILAR criteria constitute a homogeneous patient population.
A novel three‐dimensional tool for teaching human neuroanatomy
Authors: Estevez Maureen E. , Lindgren Kristen A. , Bergethon Peter R.
Published: October 2010

Three‐dimensional (3D) visualization of neuroanatomy can be challenging for medical students. This knowledge is essential in order for students to correlate cross‐sectional neuroanatomy and whole brain specimens within neuroscience curricula and to interpret clinical and radiological information as clinicians or researchers. This study implemented and evaluated a new tool for teaching 3D neuroanatomy to first‐year medical students at Boston University School of Medicine. Students were randomized into experimental and control classrooms. All students were taught neuroanatomy according to traditional 2D methods. Then, during laboratory review, the experimental group constructed 3D color‐coded physical models of the periventricular structures, while the control group re‐examined 2D brain cross‐sections. At the end of the course, 2D and 3D spatial relationships of the brain and preferred learning styles were assessed in both groups. The overall quiz scores for the experimental group were significantly higher than the control group (t(85) = 2.02, P < 0.05). However, when the questions were divided into those requiring either 2D or 3D visualization, only the scores for the 3D questions were significantly higher in the experimental group (F1,85= 5.48, P = 0.02). When surveyed, 84% of students recommended repeating the 3D activity for future laboratories, and this preference was equally distributed across preferred learning styles (χ2 = 0.14, n.s.). Our results suggest that our 3D physical modeling activity is an effective method for teaching spatial relationships of brain anatomy and will better prepare students for visualization of 3D neuroanatomy, a skill essential for higher education in neuroscience, neurology, and neurosurgery. Anat Sci Educ. © 2010 American Association of Anatomists.
Proteins conjugated to poly(butyl cyanoacrylate) nanoparticles as potential neuroprotective agents
Authors: Reukov Vladimir , Maximov Victor , Vertegel Alexey
Published: October 2010

Poly(butyl cyanoacrylate) (PBCA) nanoparticles (NPs) can penetrate blood–brain barrier providing the means for drug delivery to the central nervous system. Here, we study attachment of superoxide dismutase (SOD) and anti‐glutamate N‐methyl D‐aspartate receptor 1 (NR1) antibody to PBCA NPs with the ultimate goal to design neuroprotective therapeutics for treatment of secondary spinal cord injury. Synthesis of monodispersed, ∼200 nm‐diameter PBCA NPs was performed using polymerization at pH 2.0 with Dextran 70,000 as the stabilizer. Sulfo‐HSAB spacers were used to covalently attach SOD and NR1 antibodies to the dextran‐coated NPs. The prepared protein–NP conjugates possessed SOD activity and were capable of binding to rat cerebellar neurons. Thus, SOD and NR1 antibodies may be simultaneously attached to PBCA NPs while retaining at least a fraction of enzymatic activity and receptor‐binding ability. The conjugates showed neuroprotective efficacy in vitro with rat cerebellar cell cultures challenged by superoxide. Biotechnol. Bioeng. 2011;108: 243–252. © 2010 Wiley Periodicals, Inc.
Pancreatic cell immobilization in alginate beads produced by emulsion and internal gelation
Authors: Hoesli Corinne A. , Raghuram Kamini , Kiang Roger L.J. , Mocinecová Dušana , Hu Xiaoke , Johnson James D. , Lacík Igor , Kieffer Timothy J. , Piret James M.
Published: October 2010

Alginate has been used to protect transplanted pancreatic islets from immune rejection and as a matrix to increase the insulin content of islet progenitor cells. The throughput of alginate bead generation by the standard extrusion and external gelation method is limited by the rate of droplet formation from nozzles. Alginate bead generation by emulsion and internal gelation is a scaleable alternative that has been used with biological molecules and microbial cells, but not mammalian cells. We describe the novel adaptation of this process to mammalian cell immobilization. After optimization, the emulsion process yielded 90 ± 2% mouse insulinoma 6 (MIN6) cell survival, similar to the extrusion process. The MIN6 cells expanded at the same rate in both bead types to form pseudo‐islets with increased glucose stimulation index compared to cells in suspension. The emulsion process was suitable for primary pancreatic exocrine cell immobilization, leading to 67 ± 32 fold increased insulin expression after 10 days of immobilized culture. Due to the scaleability and broad availability of stirred mixers, the emulsion process represents an attractive option for laboratories that are not equipped with extrusion‐based cell encapsulators, as well as for the production of immobilized or encapsulated cellular therapeutics on a clinical scale. Biotechnol. Bioeng. 2011;108: 424–434. © 2010 Wiley Periodicals, Inc.
Countercurrent tangential chromatography for large‐scale protein purification
Authors: Shinkazh Oleg , Kanani Dharmesh , Barth Morgan , Long Matthew , Hussain Daniar , Zydney Andrew L.
Published: October 2010

Recent advances in cell culture technology have created significant pressure on the downstream purification process, leading to a “downstream bottleneck” in the production of recombinant therapeutic proteins for the treatment of cancer, genetic disorders, and cardiovascular disease. Countercurrent tangential chromatography overcomes many of the limitations of conventional column chromatography by having the resin (in the form of a slurry) flow through a series of static mixers and hollow fiber membrane modules. The buffers used in the binding, washing, and elution steps flow countercurrent to the resin, enabling high‐resolution separations while reducing the amount of buffer needed for protein purification. The results obtained in this study provide the first experimental demonstration of the feasibility of using countercurrent tangential chromatography for the separation of a model protein mixture containing bovine serum albumin and myoglobin using a commercially available anion exchange resin. Batch uptake/desorption experiments were used in combination with critical flux data for the hollow fiber filters to design the countercurrent tangential chromatography system. A two‐stage batch separation yielded the purified target protein at >99% purity with 94% recovery. The results clearly demonstrate the potential of using countercurrent tangential chromatography for the large‐scale purification of therapeutic proteins. Biotechnol. Bioeng. 2011; 108:582–591. © 2010 Wiley Periodicals, Inc.
Effects of vibration on differentiation of cultured PC12 cells
Authors: Ito Yukiko , Kimura Tsuyoshi , Nam Kwangwoo , Katoh Ayako , Masuzawa Toru , Kishida Akio
Published: October 2010

Different types of physiological‐mechanical stress, such as shear stress in vascular endothelial cells or hydrostatic pressure in chondrocytes are well known as regulators of cell function. In this study, the effects of vibration, a type of non‐physiological mechanical stimulation, on differentiation of rat pheochromocytoma (PC12) cells are reported. A nano‐vibration system was designed to produce nanometer‐scale vibration. The frequency and amplitude of the nano‐vibrations were monitored by a capacitance displacement sensor connected to an oscilloscope. When PC12 cells exposed to nerve growth factor were subjected to vibration at 10 kHz, differentiation and elongation of their neurites were promoted earlier in the culture. Vibration promoted differentiation of PC12 cells. This approach could therefore also be promising for determining of the effects of the physical environment on cell differentiation. Biotechnol. Bioeng. 2011; 108:592–599. © 2010 Wiley Periodicals, Inc.