9,565 research outputs found

    A Comparison of the Ovulation Method With the CUE Ovulation Predictor in Determining the Fertile Period

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    The purpose of this study was to compare the CUE Ovulation Predictor with the ovulation method in determining the fertile period. Eleven regularly ovulating women measured their salivary and vaginal electrical resistance (ER) with the CUE, observed their cervical-vaginal mucus, and measured their urine for a luteinizing hormone (LH) surge on a daily basis. Data from 21 menstrual cycles showed no statistical difference (T= 0.33, p= 0.63) between the CUE fertile period, which ranged from 5 to 10 days (mean = 6.7 days, SD = 1.6), and the fertile period of the ovulation method, which ranged from 4 to 9 days (mean = 6.5 days, SD = 2.0). The CUE has potential as an adjunctive device in the learning and use of natural family planning methods

    Secondary homotopy groups

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    Secondary homotopy groups supplement the structure of classical homotopy groups. They yield a track functor on the track category of pointed spaces compatible with fiber sequences, suspensions and loop spaces. They also yield algebraic models of homotopy types with homotopy groups concentrated in two consecutive dimensions.Comment: We added further commets and references to make the paper more easily readabl

    Effectively four-dimensional spacetimes emerging from d=5 Einstein-Gauss-Bonnet Gravity

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    Einstein-Gauss-Bonnet gravity in five-dimensional spacetime provides an excellent example of a theory that, while including higher-order curvature corrections to General Relativity, still shares many of its features, such as second-order field equations for the metric. We focus on the largely unexplored case where the coupling constants of the theory are such that no constant-curvature solution is allowed, leaving open the question of what the vacuum state should then be. We find that even a slight deviation from the anti-de Sitter Chern-Simons theory, where the vacuum state is five-dimensional AdS spacetime, leads to a complete symmetry breakdown, with the fifth dimension either being compactified into a small circle or shrinking away exponentially with time. A complete family of solutions, including duality relations among them, is uncovered and shown to be unique within a certain class. This dynamical dimensional reduction scenario seems particularly attractive as a means for higher-dimensional theories to make contact with our four-dimensional world.Comment: 9 pages, 4 figures. v2: New section on geometrical significance of solutions. Final version for CQ

    Interacción Rhizobium leguminosarum bv trifolii y hongos micorrícicos en un Andisol con diferentes niveles de saturación de aluminio

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    Aluminium phytotoxicity is a serious limitation of the productivity of prairies growing on volcanic soil by affecting nodulation and effectiveness of Rhizobium. The aim of this study was to select Rhizobium strains to determine the effect as inoculant on Trifolium repens cropped in an Andisol with different aluminium saturation levels. Acidity tolerance (pH 4.5 and 6.0) of twelve Rhizobium strains of collection at three Al levels (100, 200, 300 μM) was evaluated in mineral nutritive medium vitro. Simultaneously, in a greenhouse trial, strains effectivity were tested by inoculation of Trifolium pratense growing in an acidic Andisol and compared with dry matter accumulation produced by native strains. According to the results of this two trials, three Rhizobium strains (R-109, R-113 and R-115) were selected to study the effect of their inoculation on Trifolium repens growth cropped in an Andisol at four Al saturation levels (SAl1 to SAl4). In addition, the effect on arbuscular mycorrhizal propagules was also studied. Plants showed different capacity for association with the inoculated strains giving the best response R-113 at SAl1 level with positive synergism expressed by microbiological parameters such as high nodulation (16 nodules pot-1), AMF spore number (384 spores 100 g-1), root colonization percentage (45%), together with agronomical variables with an increase of aerial phytomass (93,5%) in comparison with the control. Higher Al levels had an deleterious effect on the inoculation of collection strains; therefore, with R-109 strain inoculation the smallest root growth and nodulation were observed in comparison with soil with native strains whereas R-113 was the more effective one.La fitotoxicidad por Al es una seria limitante de la productividad de praderas crecidas sobre suelos volcánicos afectando la nodulación y efectividad de los Rhizobium. El objetivo del estudio consistió en seleccionar cepas de Rhizobium de colección para estudiar su efectividad en Trifolium repens crecido en un Andisol con cepas nativas y distinta saturación de Al. Para ello se evaluó previamente en caldo nutritivo la tolerancia a la acidez y toxicidad por Al de 12 cepas de colección mediante control de curvas de crecimiento. Paralelamente, se inocularon los Rhizobium en un Andisol para evaluar su efectividad mediante rendimiento de Trifolium pratense. Se seleccionaron las cepas R-109, R-113 y R-115 para inocularlas en el Andisol utilizando cuatro tratamientos: suelo adicionado de 2 Mg CaCO3 ha-1 (SAl1), un testigo (SAl2) y suelo adicionado de dos niveles de saturación Al (SAl1, SAl4) utilizando Trifolium repens como hospedero. Las plantas mostraron capacidad para asociarse con las especies inoculadas presentando mayor efectividad R-113-SAl1 sinergismo positivo expresado en variables microbiológicas como nodulación (16 nódulos maceta-1), esporas de hongos micorrícicos arbusculares, HMA (384 esporas 100g-1), colonización HMA (45%) junto con variables agronómicas alcanzándose un incremento de biomasa foliar (93,5%) frente al testigo. Niveles más elevados de Al afectaron la inoculación con cepas de colección; así, con R-109 se obtuvo el menor crecimiento radical y nodulación respecto al suelo natural mientras que R-113 fue la cepa más efectiva

    Destruction of first-order phase transition in a random-field Ising model

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    The phase transitions that occur in an infinite-range-interaction Ising ferromagnet in the presence of a double-Gaussian random magnetic field are analyzed. Such random fields are defined as a superposition of two Gaussian distributions, presenting the same width σ\sigma. Is is argued that this distribution is more appropriate for a theoretical description of real systems than its simpler particular cases, i.e., the bimodal (σ=0\sigma=0) and the single Gaussian distributions. It is shown that a low-temperature first-order phase transition may be destructed for increasing values of σ\sigma, similarly to what happens in the compound FexMg1xCl2Fe_{x}Mg_{1-x}Cl_{2}, whose finite-temperature first-order phase transition is presumably destructed by an increase in the field randomness.Comment: 13 pages, 3 figure

    Surface Vacuum Energy in Cutoff Models: Pressure Anomaly and Distributional Gravitational Limit

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    Vacuum-energy calculations with ideal reflecting boundaries are plagued by boundary divergences, which presumably correspond to real (but finite) physical effects occurring near the boundary. Our working hypothesis is that the stress tensor for idealized boundary conditions with some finite cutoff should be a reasonable ad hoc model for the true situation. The theory will have a sensible renormalized limit when the cutoff is taken away; this requires making sense of the Einstein equation with a distributional source. Calculations with the standard ultraviolet cutoff reveal an inconsistency between energy and pressure similar to the one that arises in noncovariant regularizations of cosmological vacuum energy. The problem disappears, however, if the cutoff is a spatial point separation in a "neutral" direction parallel to the boundary. Here we demonstrate these claims in detail, first for a single flat reflecting wall intersected by a test boundary, then more rigorously for a region of finite cross section surrounded by four reflecting walls. We also show how the moment-expansion theorem can be applied to the distributional limits of the source and the solution of the Einstein equation, resulting in a mathematically consistent differential equation where cutoff-dependent coefficients have been identified as renormalizations of properties of the boundary. A number of issues surrounding the interpretation of these results are aired.Comment: 22 pages, 2 figures, 1 table; PACS 03.70.+k, 04.20.Cv, 11.10.G

    Human Resource Management Practices and Organizational Performance in Public Sector Organizations: with reference to Development Officers in the Colombo District in Sri Lanka

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    Human resources management concerns how people are employed, utilized, and maintained effectively and efficiently in achieving organizational objectives.   The performance of any organization largely depends on its human resources. Among the human resources management practices, recruitment, and selection of the right pool of employees, proper training and development, performance appraisal, and compensation directly affect achieving organizational objectives. However, these Human Resource (HR) practices in the public sector, especially in relation to the position of Development Officers (DOs) of Sri Lanka have not been practiced in an effective manner. Recruitment of Graduates as Development Officers has been a major reason for increasing the growth of public service in the country. Since the 1990s, the government of Sri Lanka has practiced bulk recruitment of graduates without having a clear and formal duty list, service minutes, recruitment procedures, training and development programs, promotion policy, and salary scale. The main purpose of this study is to discuss the existing Human Resource Management (HRM) practices, identify strengths and weaknesses of the existing HRM practices, and examine how these weaknesses affect the performance of the public sector organizations in relation to Development Officers in the public sector in Sri Lanka. The study used a qualitative research method with the inductive approach. Data were collected through in-depth interviews from all 13 Divisional Secretaries in the Colombo District and the data were analyzed narratively. The study revealed that the existing recruiting, training, and performance appraisal practices negatively affect the performance of the public sector due to some weaknesses in these practices.  Finally, this study proposes policy recommendations for improving the effectiveness of these practices for enhancing the public sector performance in Sri Lanka. Keywords: Human resource management practices, Development officers, Public sector, Sri Lank

    Regulation of Marginal Zone B-Cell Differentiation by MicroRNA-146a.

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    B-cell development in the bone marrow is followed by specification into functional subsets in the spleen, including marginal zone (MZ) B-cells. MZ B-cells are classically characterized by T-independent antigenic responses and require the elaboration of distinct gene expression programs for development. Given their role in gene regulation, it is not surprising that microRNAs are important factors in B-cell development. Recent work demonstrated that deficiency of the NFκB feedback regulator, miR-146a, led to a range of hematopoietic phenotypes, but B-cell phenotypes have not been extensively characterized. Here, we found that miR-146a-deficient mice demonstrate a reduction in MZ B-cells, likely from a developmental block. Utilizing high-throughput sequencing and comparative analysis of developmental stage-specific transcriptomes, we determined that MZ cell differentiation was impaired due to decreases in Notch2 signaling. Our studies reveal miR-146a-dependent B-cell phenotypes and highlight the complex role of miR-146a in the hematopoietic system

    Dynamical reentrance and geometry imposed quantization effects in Nb-AlOx-Nb Josephson junction arrays

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    In this paper, we report on different phenomena related to the magnetic properties of artificially prepared highly ordered (periodic) two-dimensional Josephson junction arrays (2D-JJA) of both shunted and unshunted Nb-AlOx-Nb tunnel junctions. By employing mutual-inductance measurements and using a high-sensitive bridge, we have thoroughly investigated (both experimentally and theoretically) the temperature and magnetic field dependence of complex AC susceptibility of 2D-JJA. We also demonstrate the use of the scanning SQUID microscope for imaging the local flux distribution within our unshunted arrays

    Views of fishermen and aquaculture authorities on the stocking of tilapia and carp species in the dry zone reservoirs, sri lanka

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    A survey was conducted to find out the views of the fishermen and aquaculture authorities on the introduction of Tilapia or Carp species in the fresh water bodies in the Dry Zone of Sri Lanka. This survey explored the factors affecting the choice of either one of the two fish species for inland aquaculture using data collected from the regional aquaculture extension officers and inland fishermen by means of a structured questionnaire. Binary logistic regression was used to analyze the factors affecting the choice of Tilapia vs. Carp by fishermen and the authorities. A correlation analysis demonstrated strong (r≥0.8) positive and significant (p<0.05) correlations between preference for Tilapia by fishermen and market demand (r=0.8), size compatibility (r=0.9) and consumer preference (r=0.8). Correlations were insignificant with fishing effort and income. Market demand, size compatibility and consumer preference are crucial factors in the preference of fishermen for Tilapia over Carp. The same view was expressed by the regional fisheries authorities as well. A revision of the present contradicting stocking policy could therefore, generate more social and economic benefit
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