Effects of X-ray irradiation on human spermatogenesis

Direct cell kill and inhibition of mitosis have been suggested as mechanisms to explain the occurrence of absolute sterility following the irradiation of the testes. In order to obtain information on the existence and dose dependency of the mechanisms for man, a controlled study was initiated. Sixty-four men received a single midorgan dose to both of their testes ranging from 7.5 to 400r (f = .95). It was deduced from resulting pre-sterile period and sterile period data that both cell kill and mitosis halting mechanisms were operating. The maximum observed sterile period was 501 days with eventual recovery observed in each individual where the follow-up was complete. Thus man appears to be highly radiosensitive in regard to temporary sterility but quite radioresistant in regard to permanent sterility

Customized design of hearing aids using statistical shape learning

3D shape modeling is a crucial component of rapid prototyping systems that customize shapes of implants and prosthetic devices to a patient’s anatomy. In this paper, we present a solution to the problem of customized 3D shape modeling using a statistical shape analysis framework. We design a novel method to learn the relationship between two classes of shapes, which are related by certain operations or transformation. The two associated shape classes are represented in a lower dimensional manifold, and the reduced set of parameters obtained in this subspace is utilized in an estimation, which is exemplified by a multivariate regression in this paper.We demonstrate our method with a felicitous application to estimation of customized hearing aid devices

Relaxation in the 3D ordered CoTAC spin chain by quantum nucleation of 0D domain walls

We have shown that resonant quantum tunnelling of the magnetisation (QTM), until now observed only in 0D cluster systems (SMMs), occurs in the molecular Ising spin chain, CoTAC ([(CH_3)_3NH]CoCl_3 - 2H_2O) which orders as a canted 3D-antiferromagnet at T_C=4.15 K. This effect was observed around a resonant like field value of 1025 Oe. We present here measurements of the relaxation of the magnetisation as a function of time, from the zero field cooled (ZFC) antiferromagnet state and from the saturated ferromagnet state. We show that, at the resonant field, the relaxation from the saturated state occurs in a complicated process, whereas, surprisingly, in the case of the ZFC state, the relaxation is exponential.Comment: 4 pages, 5 figures, LT25 proceeding

The inexorable resistance of inertia determines the initial regime of drop coalescence

Drop coalescence is central to diverse processes involving dispersions of drops in industrial, engineering and scientific realms. During coalescence, two drops first touch and then merge as the liquid neck connecting them grows from initially microscopic scales to a size comparable to the drop diameters. The curvature of the interface is infinite at the point where the drops first make contact, and the flows that ensue as the two drops coalesce are intimately coupled to this singularity in the dynamics. Conventionally, this process has been thought to have just two dynamical regimes: a viscous and an inertial regime with a crossover region between them. We use experiments and simulations to reveal that a third regime, one that describes the initial dynamics of coalescence for all drop viscosities, has been missed. An argument based on force balance allows the construction of a new coalescence phase diagram

Development of Collembolans after coversion towards organic farming

In Northern Germany, a diverse and complex experimental farm of the Federal Agricultural Research Centre (FAL) was set-up in 2001 covering all main aspects of organic farming. Previously, the 600 ha farm had been managed conventionally. Adjacent conventional farms were used as reference. The aim of this project was to study collembolans, microbial biomass and soil organic carbon in six organically farmed fields managed as a crop rotation of six different crops compared with an adjacent conventionally managed field. We hypothesised that the specific management in organic farming promotes soil biota. Soil samples were taken during the growing season in 2004. Collembolan abundances and microbial biomass were lower under organic management, but, generally, collembolan diversity was higher in organically farmed fields combined with a shifting in the dominance structure of the species. This result reveals that, even after three years, the soil biota is still changing with management conversion

Using Ecological Data as a Foundation for Decision-Making in the USA

Decisions that impact the quality of aquatic systems are being made daily throughout the world based on little or no ecological information (Barbour et al., 2004). Monitoring information, based on scientifically and rigorously tested ecological indicators, is integral to water quality management programs for protecting human health, preserving and restoring ecosystem integrity, and sustaining a viable economy. Under the Clean Water Act of the United States, water quality agencies of the states and tribes are required to conduct monitoring and assessment to address the mandates of the law. However, recent critiques of water monitoring programs have claimed that the United States Environmental Protection Agency (U.S. EPA) and State water quality agencies cannot make statistically valid inferences about water quality and the condition of the Nation's waters, i.e., whether they are improving, degrading or remaining the same; furthermore, we lack data to support management decisions regarding the Nation's aquatic resources. The National Wadeable Streams Assessment Program (WSA) was established in early 2004 to answer the question of what is the status of the Nation's waters, and to maximize partnerships among U.S. EPA, States and Tribes, and other agencies to establish a framework to address issues at state and local scales. Ecological data in any form require some measure of translation to be useable by the environmental manager, i.e., a hierarchy exists in the translation process from basic biological data in its rawest form through a series of manipulations in the analysis phase to reporting of the results and interpretation. This nationally focused program is a step towards ensuring adequate monitoring data exist in the future to assess water quality and make sound watershed management decisions throughout the USA; actions are taken to protect and restore water quality that maximize benefits and minimize costs; and sound science forms the basis of making informed decisions regarding our aquatic resource.Diariamente se están tomando decisiones que inciden en la calidad de los sistemas acuáticos basadas en escasa o ninguna información ecológica (Barbour et al., 2004). La información obtenida en programas de gestión, basada en indicadores cient'ıficos y basados en indicadores ecológicos, se integra en programas de gestión de la calidad del agua para la protección de la salud humana, la preservación o restauración de la integridad de los ecosistemas y el sostenimiento de una economía viable. Por mandato del Acta sobre el Agua Limpia de los Estados Unido, se han creado agencias a nivel de Estados o regiones para realizar programas de estudio y gestión para cumplir el mandato de la ley. No obstante, recientemente han surgido críticas a los programas de gestión señalando que la Agencia de Protección Ambiental de los Estados Unidos (U.S. EPA) y las agencias de calidad del agua estatales no pueden realizar inferencias estadísticamente válidas acerca de la calidad del agua y de la situación de las aguas de la nación, p. e. si estan mejorando, degradando o permanecen igual. Además, no tenemos datos para apoyar las decisiones de gestión en relación con los recursos acuáticos nacionales. El Programa de Estudio de los Ríos Vadeables (WSA) se estableció en 2004 para responder a la pregunta de cual es la situación de las aguas de la nación, y para maximizar la colaboración entre U.S. EPA, y las agencias estatales, locales y similares para realizar un marco de trabajo que permita establecer los objetivos a escalas estatal y local. La información ecológica de cualquier tipo requiere algunas medidas de traducción para que sea utilizable por los gestores ambientales, p. e. existe una jerarquía en el proceso de traslación desde datos biológicos básicos, en su forma poco elaborada, hasta una serie de manipulaciones en la fase de análisis para los informes de resultados y su interpretación. Este programa enfocado a nivel nacional es un paso para asegurar que existen datos adecuados de gestión a través de todo el país. Se están realizando actuaciones para proteger y mejorar la calidad del agua que maximice los beneficios y minimice los costes a la vez que establezcan las bases científicas para tomar decisiones teniendo en cuenta nuestros recursos acuáticos

TransportDB: a comprehensive database resource for cytoplasmic membrane transport systems and outer membrane channels

TransportDB () is a comprehensive database resource of information on cytoplasmic membrane transporters and outer membrane channels in organisms whose complete genome sequences are available. The complete set of membrane transport systems and outer membrane channels of each organism are annotated based on a series of experimental and bioinformatic evidence and classified into different types and families according to their mode of transport, bioenergetics, molecular phylogeny and substrate specificities. User-friendly web interfaces are designed for easy access, query and download of the data. Features of the TransportDB website include text-based and BLAST search tools against known transporter and outer membrane channel proteins; comparison of transporter and outer membrane channel contents from different organisms; known 3D structures of transporters, and phylogenetic trees of transporter families. On individual protein pages, users can find detailed functional annotation, supporting bioinformatic evidence, protein/DNA sequences, publications and cross-referenced external online resource links. TransportDB has now been in existence for over 10 years and continues to be regularly updated with new evidence and data from newly sequenced genomes, as well as having new features added periodically