The structures of anthranilate synthase of Serratia marcescens crystallized in the presence of (i) its substrates, chorismate and glutamine, and a product, glutamate, and (ii) its end-product inhibitor, l-tryptophan

The crystal structure of anthranilate synthase (AS) from Serratia marcescens, a mesophilic bacterium, has been solved in the presence of its substrates, chorismate and glutamine, and one product, glutamate, at 1.95 Å, and with its bound feedback inhibitor, tryptophan, at 2.4 Å. In comparison with the AS structure from the hyperthermophile Sulfolobus solfataricus, the S. marcescens structure shows similar subunit structures but a markedly different oligomeric organization. One crystal form of the S. marcescens enzyme displays a bound pyruvate as well as a putative anthranilate (the nitrogen group is ambiguous) in the TrpE subunit. It also confirms the presence of a covalently bound glutamyl thioester intermediate in the TrpG subunit. The tryptophan-bound form reveals that the inhibitor binds at a site distinct from that of the substrate, chorismate. Bound tryptophan appears to prevent chorismate binding by a demonstrable conformational effect, and the structure reveals how occupancy of only one of the two feedback inhibition sites can immobilize the catalytic activity of both TrpE subunits. The presence of effectors in the structure provides a view of the locations of some of the amino acid residues in the active sites. Our findings are discussed in terms of the previously described AS structure of S. solfataricus, mutational data obtained from enteric bacteria, and the enzyme's mechanism of action.

Integrated fossil and molecular data reconstruct bat echolocation

Molecular and morphological data have important roles in illuminating evolutionary history. DNA data often yield well resolved phylogenies for living taxa, but are generally unattainable for fossils. A distinct advantage of morphology is that some types of morphological data may be collected for extinct and extant taxa. Fossils provide a unique window on evolutionary history and may preserve combinations of primitive and derived characters that are not found in extant taxa. Given their unique character complexes, fossils are critical in documenting sequences of character transformation over geologic time and may elucidate otherwise ambiguous patterns of evolution that are not revealed by molecular data alone. Here, we employ a methodological approach that allows for the integration of molecular and paleontological data in deciphering one of the most innovative features in the evolutionary history of mammals—laryngeal echolocation in bats. Molecular data alone, including an expanded data set that includes new sequences for the A2AB gene, suggest that microbats are paraphyletic but do not resolve whether laryngeal echolocation evolved independently in different microbat lineages or evolved in the common ancestor of bats and was subsequently lost in megabats. When scaffolds from molecular phylogenies are incorporated into parsimony analyses of morphological characters, including morphological characters for the Eocene taxa Icaronycteris, Archaeonycteris, Hassianycteris, and Palaeochiropteryx, the resulting trees suggest that laryngeal echolocation evolved in the common ancestor of fossil and extant bats and was subsequently lost in megabats. Molecular dating suggests that crown-group bats last shared a common ancestor 52 to 54 million years ago.

On the role of selective attention in visual perception

What is the role of selective attention in visual perception? Before answering this question, it is necessary to differentiate between attentional mechanisms that influence the identification of a stimulus from those that operate after perception is complete. Cognitive neuroscience techniques are particularly well suited to making this distinction because they allow different attentional mechanisms to be isolated in terms of timing and/or neuroanatomy. The present article describes the use of these techniques in differentiating between perceptual and postperceptual attentional mechanisms and then proposes a specific role of attention in visual perception. Specifically, attention is proposed to resolve ambiguities in neural coding that arise when multiple objects are processed simultaneously. Evidence for this hypothesis is provided by two experiments showing that attention—as measured electrophysiologically—is allocated to visual search targets only under conditions that would be expected to lead to ambiguous neural coding.

Detecting Holocene changes in thermohaline circulation

Throughout the last glacial cycle, reorganizations of deep ocean water masses were coincident with rapid millennial-scale changes in climate. Climate changes have been less severe during the present interglacial, but evidence for concurrent deep ocean circulation change is ambiguous.

Loss of sequences 3' to the testis-determining gene, SRY, including the Y pseudoautosomal boundary associated with partial testicular determination.

The condition termed 46,XY complete gonadal dysgenesis is characterized by a completely female phenotype and streak gonads. In contrast, subjects with 46,XY partial gonadal dysgenesis and those with embryonic testicular regression sequence usually present ambiguous genitalia and a mix of Müllerian and Wolffian structures. In 46,XY partial gonadal dysgenesis gonadal histology shows evidence of incomplete testis determination. In 46,XY embryonic testicular regression sequence there is lack of gonadal tissue on both sides. Various lines of evidence suggest that embryonic testicular regression sequence is a variant form of 46,XY gonadal dysgenesis. The sex-determining region Y chromosome gene (SRY) encodes sequences for the testis-determining factor. To date germ-line mutations in SRY have been reported in approximately 20% of subjects with 46,XY complete gonadal dysgenesis. However, no germ-line mutations of SRY have been reported in subjects with the partial forms. We studied 20 subjects who presented either 46,XY partial gonadal dysgenesis or 46,XY embryonic testicular regression sequence. We examined the SRY gene and the minimum region of Y-specific DNA known to confer a male phenotype. The SRY-open reading frame (ORF) was normal in all subjects. However a de novo interstitial deletion 3' to the SRY-ORF was found in one subject. Although it is possible that the deletion was unrelated to the subject's phenotype, we propose that the deletion was responsible for the abnormal gonadal development by diminishing expression of SRY. We suggest that the deletion resulted either in the loss of sequences necessary for normal SRY expression or in a position effect that altered SRY expression. This case provides further evidence that deletions of the Y chromosome outside the SRY-ORF can result in either complete or incomplete sex reversal.

Homophilic adhesion mediated by the neural cell adhesion molecule involves multiple immunoglobulin domains.

The neural cell adhesion molecule (N-CAM) mediates homophilic binding between a variety of cell types including neurons, neurons and glia, and neurons and muscle cells. The mechanism by which N-CAM on one cell interacts with N-CAM on another, however, is unknown. Attempts to identify which of the five immunoglobulin-like domains (Ig I-V) and the two fibronectin type III repeats (FnIII 1-2) in the extracellular region of N-CAM are involved in this process have led to ambiguous results. We have generated soluble recombinant proteins corresponding to each of the individual immunoglobulin domains and the combined FnIII 1-2 and prepared polyclonal antibodies specific for each. The purified proteins and antibodies were used in aggregation experiments with fluorescent microspheres and chicken embryo brain cells to determine possible contributions of each domain to homophilic adhesion. The recombinant domains were tested for their ability to bind to purified native N-CAM, to bind to each other, and to inhibit the aggregation of N-CAM on microspheres and the aggregation of neuronal cells. Each of the immunoglobulin domains bound to N-CAM, and in solution all of the immunoglobulin domains inhibited the aggregation of N-CAM-coated microspheres. Soluble Ig II, Ig III, and Ig IV inhibited neuronal aggregation; antibodies against whole N-CAM, the Ig III domain, and the Ig I domain all strongly inhibited neuronal aggregation, as well as the aggregation of N-CAM-coated microspheres. Of all the domains, the third immunoglobulin domain alone demonstrated the ability to self-aggregate, whereas Ig I bound to Ig V and Ig II bound to Ig IV. The combined FnIII 1-2 exhibited a slight ability to self-aggregate but did not bind to any of the immunoglobulin-like domains. These results suggest that N-CAM-N-CAM binding involves all five immunoglobulin domains and prompt the hypothesis that in homophilic cell-cell binding mediated by N-CAM these domains may interact pairwise in an antiparallel orientation.

Post T Tauri stars in the solar neighborhood: isolated or members of young associations and moving groups

Post T Tauri stars (PTTS) are late-type stars in the age range between 10 and 100 Myr filling the gap between T Tauri (TTs) and zero-age: main sequence phases. This period of evolution remains ambiguous and until now different studies of young stars have failed to find the numbers of PTTS that are expected. In the last years, some PTTS have been identified among the X-ray detected pre-main sequence stars in some star-forming regions. More recently, additional PTTS have been identified in young associations and moving groups (β Pic, TW Hya, Tucana/Horologium, and the AB Dor). However, many isolated PTTS still remain undiscovered. In this contribution, we compiled the PTTS previously identified in the literature, and identified new candidates using the information provided by the high resolution spectra obtained during our surveys of late-type stars possible members to young moving groups, FGK stars in the solar neighborhood, and RasTyc sample. To identify PTTS we applied an age-oriented definition using relative age indicators (Li abundance, chromospheric and coronal emission and the kinematics) as well as color-magnitude diagrams and pre-main sequence isochrones.

Erratum: Suppression of localization in kronig-penney models with correlated disorder (Vol. 49, PG 147, 1994)

We consider the electron dynamics and transport properties of one-dimensional continuous models with random, short-range correlated impurities. We develop a generalized Poincare map formalism to cast the Schrodinger equation for any potential into a discrete set of equations, illustrating its application by means of a specific example. We then concentrate on the case of a Kronig-Penney model with dimer impurities. The previous technique allows us to show that this model presents infinitely many resonances (zeroes of the reflection coefficient at a single dimer) that give rise to a band of extended states, in contradiction with the general viewpoint that all one-dimensional models with random potentials support only localized states. We report on exact transfer-matrix numerical calculations of the transmission coefFicient, density of states, and localization length for various strengths of disorder. The most important conclusion so obtained is that this kind of system has a very large number of extended states. Multifractal analysis of very long systems clearly demonstrates the extended character of such states in the thermodynamic limit. In closing, we brieBy discuss the relevance of these results in several physical contexts.

Avaliação da percepção sobre interdisciplinaridade nas unidades de saúde USF Paranapiacaba, US Vila Helena e CEO Vila Guilherme

É necessário compreender que o indivíduo, no processo saúde-doença, precisa receber atenção completa, que envolva várias disciplinas atuando de forma conjunta, numa visão que envolve integralidade de ações (Saupe et al., 2007; Salvador et al., 2011). Uma das principais características dos serviços de saúde hoje em dia no país é o atendimento feito por equipes multiprofissionais, cujo entrosamento, entendimento e troca de saberes entre seus membros levam à interdisciplinaridade (Salvador et al., 2011), tema central deste trabalho de pesquisa. Atendimento interdisciplinar envolve trabalho recíproco, criando relações sociais horizontais, contrariamente ao que ocorre no modelo de assistência tradicional, hegemônico. Exige que o saber do outro seja ouvido e pensado, inclusive dos indivíduos e das comunidades assistidos (Leite; Veloso, 2008). Este estudo, do tipo quali-quantitativo, tem por objetivo analisar as percepções que trabalhadores e usuários de três unidades de saúde, com estratégias distintas de atendimento, apresentam sobre interdisciplinaridade. Busca-se destacar dificuldades e possíveis meios facilitadores para sua prática diária na perspectiva de profissionais de saúde e usuários dessas três unidades de saúde. Foram aplicados questionários com perguntas fechadas semiestruturadas e abertas, cujos resultados foram submetidos à análise quantitativa, pela técnica descritiva de análise de frequência, e análise qualitativa pela técnica hermenêutica dialética, conforme preconizada por Minayo (2004). À luz dessa modalidade qualitativa de pesquisa aplicada aos profissionais surgiram três categorias: Meios para aumento da interdisciplinaridade; Fatores que afetam a interdisciplinaridade, subdivididos em Incentivadores, Desmotivadores e Ambíguos; e Resultados da interdisciplinaridade. Em relação aos usuários, as categorias emergentes foram: Desinteresse; Visão assistencial individualista e Vantagens da interdisciplinaridade. Os resultados encontrados foram: todas as categorias profissionais sentiram falta de outros profissionais em grupos educativos. A ausência mais sentida foi assistente social (18,75%). A estratégia interdisciplinar mais lembrada foi \"reuniões\" (38,6%). Falta noção de que é necessário trocar informações de forma efetiva, compreensível e satisfatória para todos. Mostrou-se importante aproveitar esses momentos para discutir protocolos e rotinas. Instrumento relevante para aumentar as trocas entre os profissionais foi a capacitação (13,6%) que melhora o relacionamento em equipe ao diminuir inseguranças. Trocas de informações em equipe multidisciplinar podem transformála em interdisciplinar. Pertencimento foi fato importante para a interdisciplinaridade, assim como dialogar, tolerar, respeitar, ouvir, ser flexível e enxergar o que está além de si, com interação social, horizontal. Número reduzido de profissionais, tomar conhecimento dos resultados das decisões em equipe e corresponsabilidade também foram fatores de destaque. Mais de 70% dos usuários relatou não participar de grupos educativos, evidenciando o curativismo. Os usuários valorizaram o atendimento por mais de um profissional. Acolhimento prescinde da ação interdisciplinar. Nenhum modo de atendimento foi sugerido pelos usuários. A interdisciplinaridade favorece a relação entre a equipe e o usuário, diminui espera e aumenta resolução. Na US Vila Helena, a interdisciplinaridade prescindiu de reuniões de equipe para acontecer.

Beautiful victims : childhood and the holocaust in the work of Gottfried Helnwein

"For the past three decades, contemporary artist Gottfried Helnwein has shocked viewers with his Holocaust-related paintings, drawings and installations. Born in Austria in 1948, Helnwein witnessed the immediate aftermath of World War II in Europe from a child’s perspective. Consequently, the horrifying images summoned from Helnwein’s imagination are inspired by the memories and repercussions of this tragedy. His work addresses his parents’ unwillingness to speak of the atrocities as well as the exploitation of the Holocaust in contemporary popular media. His work questions not only how such a tragedy could have taken place, but also how contemporary perception of this event has been affected by total media saturation and the passage of time. To shock viewers, Helnwein portrays strikingly realistic images of distressed, wounded and morally ambiguous children in works that have been regarded as controversial and outspoken"

A Physical and Social Study of Mountain Bike Use on Five Segments of the Continental Divide National Scenic Trail in Colorado

This capstone reviews uses of the Continental Divide National Scenic Trail. Policies governing use of the trail appear to be ambiguous, especially regarding mountain bicycles. Mountain biking has grown since the trail was created, but is not fully addressed in existing or proposed policy. 382 people on five segments of the trail in Colorado were interviewed for this capstone. Mountain bikes, hiking, and motorized recreation were observed uses. User conflict, overcrowding, degraded recreation experiences, or user displacement was not reported. User satisfaction was high and most would return. Interviewees requested increased public involvement and recognition of user needs in setting policy. Trail degradation occurs, but is unassociated with any particular use. Recommendations for trail improvement and maintenance are presented.

Una nueva técnica de construcción de grafos semánticos para la desambiguación bilingüe del sentido de las palabras

En este trabajo presentamos unos resultados preliminares obtenidos mediante la aplicación de una nueva técnica de construcción de grafos semánticos a la tarea de desambiguación del sentido de las palabras en un entorno multilingüe. Gracias al uso de esta técnica no supervisada, inducimos los sentidos asociados a las traducciones de la palabra ambigua considerada en la lengua destino. Utilizamos las traducciones de las palabras del contexto de la palabra ambigua en la lengua origen para seleccionar el sentido más probable de la traducción. El sistema ha sido evaluado sobre la colección de datos de una tarea de desambiguación multilingüe que se propuso en la competición SemEval-2010, consiguiendo superar los resultados de todos los sistemas no supervisados que participaron en aquella tarea.

Actualizaciones sobre declaraciones nutricionales y de propiedades saludables

Existe preocupación por la influencia de los determinantes sociales relacionados con la publicidad, la comunicación y la información sobre la selección de productos alimenticios para conseguir una alimentación saludable y segura. Desde este punto de vista, la legislación española normaliza este aspecto, a través del Reglamento Europeo 1924/2006 (RE1924/2006). El objetivo es asegurar y favorecer el acceso a alimentos inocuos que beneficien la salud y, evitar que la información recibida por los consumidores sea inexacta, ambigua o engañosa. El Reglamento pretende impedir que se atribuyan propiedades nutritivas y declaraciones de propiedades saludables a los alimentos sin razón o sin que exista suficiente evidencia científica. En este sentido, un grupo de profesionales de la Universidad de Alicante en diciembre de 2012 llevó a cabo la Primera Jornada de Alimentación y Nutrición, organizada por el Gabinete ALINU de la Facultad de Ciencias de la Salud de la Universidad de Alicante, relacionada con actualizaciones sobre declaraciones nutricionales y de propiedades saludables y sus implicaciones en la salud pública. Por el interés y la importancia del tema, se presenta un resumen de las ponencias desde la postura de los diferentes agentes implicados: consumidores, Administración, industria alimentaria, dietistas-nutricionistas, la Academia y la Salud Pública.

Applying semantic knowledge to the automatic processing of temporal expressions and events in natural language

This paper addresses the problem of the automatic recognition and classification of temporal expressions and events in human language. Efficacy in these tasks is crucial if the broader task of temporal information processing is to be successfully performed. We analyze whether the application of semantic knowledge to these tasks improves the performance of current approaches. We therefore present and evaluate a data-driven approach as part of a system: TIPSem. Our approach uses lexical semantics and semantic roles as additional information to extend classical approaches which are principally based on morphosyntax. The results obtained for English show that semantic knowledge aids in temporal expression and event recognition, achieving an error reduction of 59% and 21%, while in classification the contribution is limited. From the analysis of the results it may be concluded that the application of semantic knowledge leads to more general models and aids in the recognition of temporal entities that are ambiguous at shallower language analysis levels. We also discovered that lexical semantics and semantic roles have complementary advantages, and that it is useful to combine them. Finally, we carried out the same analysis for Spanish. The results obtained show comparable advantages. This supports the hypothesis that applying the proposed semantic knowledge may be useful for different languages.

Prácticas de autocuidado sexual y reproductivo en mujeres “parejas de” migrantes internacionales de San Luis Potosí, México

Los migrantes y sus parejas han sido incorporados en los discursos institucionales de salud como “sujetos en riesgo” frente a las Infecciones de Trasmisión Sexual (ITS), sin embargo la incorporación de esta población específica en la comunicación y gestión del riesgo de ITS ha sido ambigua en el contexto mexicano. El objetivo del presente acercamiento fue conocer las prácticas de autocuidado sexual y reproductivo que adoptan en su cotidianeidad mujeres parejas de migrantes y la relación de dichas medidas con la comunicación y gestión del riesgo que los Servicios de Salud realizan. Se trató de una aproximación de tipo cualitativo con 20 mujeres “de migrantes” localizadas mediante los servicios de salud, la información se recabó a través de entrevistas a profundidad que focalizaron en las esferas de “percepción del riesgo” y “Autocuidado sexual y reproductivo”. Se encontró que la mayoría de las mujeres no se reconoce vulnerable frente a las ITS y que la percepción del riesgo no es determinante en la confrontación que respecto a la amenaza puedan desarrollar, dado que los imaginarios patriarcales que prevalecen en ellas, sus parejas y el personal de salud desestiman la utilización de medidas de prevención y detección oportuna.