720 research outputs found

    On the Number of Integer Recurrence Relations

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    This paper presents the number of k-stage integer recurrence relations (IRR) over the ring  Z2   which generates sequences of maximum possible period (2k-1)2e-1 for e>1. This number corresponds to the primitive polynomials mod 2 which satisfy the condition proposed by Brent and is2(e-2)k+1(2k-1-1) for  e>3. This number is same as measured by Dai but arrived at with a different condition for maximum period. Our way of counting gives an explicit method for construction of such polynomials. Furthermore, this paper also presents the number of different sequences corresponding to such IRRs of maximum period

    Genetic variability and cluster analysis of wheat (Triticum aestivum L.) genotypes in foot hill of Nepal

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    To study the variability in wheat (Triticum aestivum L.) genotypes and to identify the superior genotypes for yield and yield attributing traits, a field experiment was conducted during November 2017 to April 2018 at Kamalamai-04, Phant, of Sindhuli district, Nepal. Thirty wheat genotypes were experimented in Alpha lattice design with 3 replications. Observations for Days to heading, days to maturity, plant height, spike length, peduncle length, flag leaf area, no. of spikes/m2, no of grains/spike, weight of kernel/spike, thousand kernel weight, grain yield and biological yield were recorded and analysis was done at 0.05 probability level. High broad sense heritability associated with high genetic advance over mean was observed for the traits, grain yield (90%, 57.52%), peduncle length (93%, 52.58%), plant height (88%, 34%), number of grains/spike (83%, 39.76%), thousand kernel weight (80%, 36.75%), kernel weight/spike (77%, 51.76%) and number of spikes/m2 (77%, 39.16%) which indicated the predominance of additive genes action in controlling the expression of these traits. UPGMA dendrogram grouped thirty genotypes into distinct five clusters. Genotypes of cluster II can be utilized for development of superior cultivar through breeding program. Among all genotypes NL 1336 was highest grain yielder with thousand kernel weight, number of grains/spike and kernel weight/spike higher than local check WK 1204. Therefore, genotypes NL 1336, BL 4837, WK 2884 and BL 4833 can be utilized in breeding program as parents for improvement of wheat lines and development of high yielding wheat variety

    Almacenamiento de biomasa y mejora del suelo en plantaciones de bambú en la región de Terai en el Himalaya central

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    This study evaluates six bamboo species, i.e., Dendrocalamus hamiltonii, Bambusa nutans, Dendrocalamus asper, Bambusa bambos, Bambusa balcooa, and Dendrocalamus strictus, regarding their growth behavior, nutrient uptake, and effect on the soil properties of the Terai region. Various aboveground growth parameters exhibited significant variations with the maximum clump girth (8.60 m) and internodal length (35.37 cm) of B. nutans, which was also reported by the culm diameter (5.70 cm) of D. hamiltonii and the number of culms per clump (65) of D. strictus. The total aboveground biomass ranged from 51.14 Mg.ha-1 in D. asper to 362.56 Mg.ha-1 in D. hamiltonii. The most significant variation in soil properties was observed in the 0-40 cm soil layer. Under D. hamiltonii, the lowest soil bulk density (1.07 g.cm3; 1.21 g.cm3) and the maximum soil porosity (59.00%; 56.40%), soil organic carbon (1.54%; 0.72%), and available soil nitrogen (228.29 kg.ha-1; 173.73 kg.ha-1) were found the 0-40 and 40-80 cm soil layers. Furthermore, significant enhancements in soil microbial population were recorded. Thus, bamboo plantations have great potential to enhance the biomass generation and fertility quotient of fallow lands.Este estudio evalúa seis especies de bambú, i.e., Dendrocalamus hamiltonii, Bambusa nutans, Dendrocalamus asper, Bambusa bambos, Bambusa balcooa y Dendrocalamus strictus, respecto a su comportamiento de crecimiento, absorción de nutrientes y efecto sobre las propiedades del suelo de la región de Terai. Varios parámetros de crecimiento sobre el suelo mostraron variaciones significativas con la circunferencia máxima del macizo (8.60 m) y la longitud internodal (35.37 cm) de B. nutans, lo cual también se reportó para diámetro del culmo (5.70 cm) de D. hamiltonii y el número de culmos por macizo (65) de D. strictus. La biomasa aérea total varió de 51.14 Mg.ha-1 en D. asper a 362.56 Mg.ha-1 en D. hamiltonii. La variación más significativa en las propiedades del suelo se observó en la capa de suelo de 0-40 cm. Bajo D. hamiltonii, la densidad aparente del suelo más baja (1.07 g.cm3; 1,21 g.cm3) y los máximos valores de porosidad del suelo (59 %; 56.40 %), carbono orgánico del suelo (1.54 %; 0.72%) y nitrógeno disponible del suelo (228.29 kg.ha-1; 173.73 kg.ha-1) se encontraron en las capas de 0-40 y 40-80 cm de profundidad. Además, se registró una mejora significativa en la población microbiana del suelo. Por lo tanto, las plantaciones de bambú tienen un gran potencial para mejorar la generación de biomasa y el cociente de fertilidad de las tierras en barbecho

    Towards Automated and Optimized Security Orchestration in Cloud SLA

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    In cloud computing, providers pool their resources and make them available to customers. Next-generation computer scientists are flocking to the cutting-edge field of cloud computing for their research and exploration of uncharted territory. There are still several barriers that cloud service providers must overcome in order to provide cloud services in accordance with service level agreements. Each cloud service provider aspires to achieve maximum performance as per Service Level Agreements (SLAs), and this is especially true when it comes to the delivery of services. A cloud service level agreement (SLA) guarantees that cloud service providers will satisfy the needs of large businesses and offer their clients with a specified list of services. The authors offer a web service level agreement–inspired approach for cloud service agreements. We adopt patterns and antipatterns to symbolize the best and worst practices of OCCI (Open Cloud Computing Interface Standard), REST (Representational State Transfer), and TOSCA (Topology and Orchestration Specification for Cloud Applications) with DevOps solutions, all of which API developers should bear in mind when designing APIs. When using this method, everything pertaining to the cloud service, from creation to deployment to measurement to evaluation to management to termination, may be handled mechanically. When distributing resources to cloud apps, our system takes into account the likelihood of SLA breaches and responds by providing more resources if necessary. We say that for optimal performance, our suggested solution should be used in a private cloud computing setting. As more and more people rely on cloud computing for their day-to-day workloads, there has been a corresponding rise in the need for efficient orchestration and management strategies that foster interoperability

    Self-Exfoliated Synthesis of Transition Metal Phosphate Nanolayers for Selective Aerobic Oxidation of Ethyl Lactate to Ethyl Pyruvate

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    Two-dimensional (2D) transition metal nanosheets are promising catalysts because of the enhanced exposure of the active species compared to their 3D counterparts. Here, we report a simple, scalable, and reproducible strategy to prepare 2D phosphate nanosheets by forming a layered structure in situ from phytic acid (PTA) and transition metal precursors. Controlled combustion of the organic groups of PTA results in interlayer carbon, which keeps the layers apart during the formation of phosphate, and the removal of this carbon results in ultrathin nanosheets with controllable layers. Applying this concept to vanadyl phosphate synthesis, we show that the method yields 2D ultrathin nanosheets of the orthorhombic ß-form, exposing abundant V4+/V5+ redox sites and oxygen vacancies. We demonstrate the high catalytic activity of this material in the vapor-phase aerobic oxidation of ethyl lactate to ethyl pyruvate. Importantly, these ß-VOPO4 compounds do not get hydrated, thereby reducing the competing hydrolysis reaction by water byproducts. The result has superior selectivity to ethyl pyruvate compared to analogous vanadyl phosphates. The catalysts are highly stable, maintaining a steady-state conversion of similar to 90% (with >80% selectivity) for at least 80 h on stream. This "self-exfoliated'' synthesis protocol opens opportunities for preparing structurally diverse metal phosphates for catalysis and other applications

    Genetic overlap between diagnostic subtypes of ischemic stroke

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    Background and Purpose: Despite moderate heritability, the phenotypic heterogeneity of ischemic stroke has hampered gene discovery, motivating analyses of diagnostic subtypes with reduced sample sizes. We assessed evidence for a shared genetic basis among the 3 major subtypes: large artery atherosclerosis (LAA), cardioembolism, and small vessel disease (SVD), to inform potential cross-subtype analyses. Methods: Analyses used genome-wide summary data for 12 389 ischemic stroke cases (including 2167 LAA, 2405 cardioembolism, and 1854 SVD) and 62 004 controls from the Metastroke consortium. For 4561 cases and 7094 controls, individual-level genotype data were also available. Genetic correlations between subtypes were estimated using linear mixed models and polygenic profile scores. Meta-analysis of a combined LAA-SVD phenotype (4021 cases and 51 976 controls) was performed to identify shared risk alleles. Results: High genetic correlation was identified between LAA and SVD using linear mixed models (rg=0.96, SE=0.47, P=9×10-4) and profile scores (rg=0.72; 95% confid

    Rapid and highly variable warming of lake surface waters around the globe

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    In this first worldwide synthesis of in situ and satellite-derived lake data, we find that lake summer surface water temperatures rose rapidly (global mean = 0.34°C decade−1) between 1985 and 2009. Our analyses show that surface water warming rates are dependent on combinations of climate and local characteristics, rather than just lake location, leading to the counterintuitive result that regional consistency in lake warming is the exception, rather than the rule. The most rapidly warming lakes are widely geographically distributed, and their warming is associated with interactions among different climatic factors—from seasonally ice-covered lakes in areas where temperature and solar radiation are increasing while cloud cover is diminishing (0.72°C decade−1) to ice-free lakes experiencing increases in air temperature and solar radiation (0.53°C decade−1). The pervasive and rapid warming observed here signals the urgent need to incorporate climate impacts into vulnerability assessments and adaptation efforts for lakes.Peer reviewe

    Measurement of the CP-Violating Asymmetry Amplitude sin2β\beta

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    We present results on time-dependent CP-violating asymmetries in neutral B decays to several CP eigenstates. The measurements use a data sample of about 88 million Y(4S) --> B Bbar decays collected between 1999 and 2002 with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We study events in which one neutral B meson is fully reconstructed in a final state containing a charmonium meson and the other B meson is determined to be either a B0 or B0bar from its decay products. The amplitude of the CP-violating asymmetry, which in the Standard Model is proportional to sin2beta, is derived from the decay-time distributions in such events. We measure sin2beta = 0.741 +/- 0.067 (stat) +/- 0.033 (syst) and |lambda| = 0.948 +/- 0.051 (stat) +/- 0.017 (syst). The magnitude of lambda is consistent with unity, in agreement with the Standard Model expectation of no direct CP violation in these modes

    T-Cell Immune Dysregulation and Mortality in Women with Human Immunodeficiency Virus

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    Summary: In women with HIV, higher activation and exhaustion of CD4+ T cells were associated with risk of non-HIV-related mortality during a median of 13.3 years of follow-up, independent of baseline demographic, behavioral, HIV-related, and cardiometabolic factors and longitudinal HIV disease progression. Background: Dysregulation of adaptive immunity is a hallmark of human immunodeficiency virus (HIV) infection that persists on antiretroviral therapy (ART). Few long-term prospective studies have related adaptive immunity impairments to mortality in HIV, particularly in women. Methods: Among 606 women with HIV in the Women's Interagency HIV Study, peripheral blood mononuclear cells collected from 2002 to 2005 underwent multiparameter flow cytometry. Underlying cause of death was ascertained from the National Death Index up to 2018. We examined associations of CD4+ and CD8+ T-cell activation (%CD38+HLA-DR+), senescence (%CD57+CD28-), exhaustion (%PD-1+), and nonactivation/normal function (%CD57-CD28+) with natural-cause, HIV-related, and non-HIV-related mortality. Results: At baseline, median participant age was 41, and 67% were on ART. Among 100 deaths during a median of 13.3 years follow-up, 90 were natural-cause (53 non-HIV-related, 37 HIV-related). Higher activation and exhaustion of CD4+ T cells were associated with risk of natural-cause and non-HIV-related mortality, adjusting for age, demographic, behavioral, HIV-related, and cardiometabolic factors at baseline. Additional adjustment for time-varying viral load and CD4+ T-cell count did not attenuate these associations. CD8+ T-cell markers were not associated with any outcomes adjusting for baseline factors. Conclusions: Persistent CD4+ T-cell activation and exhaustion may contribute to excess long-term mortality risk in women with HIV, independent of HIV disease progression
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