5,567 research outputs found

    Neotropical tadpoles: spatial and temporal distribution and habitat use in a seasonal lake in Veracruz, MĂ©xico

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    We studied a tadpole assemblage in a seasonal neotropical lake where 14 species of anurans reproduce. Tadpoles were collected monthly at nine sampling stations at depth intervals of 1 m from the surface to the bottom (13 m). Sufficient numbers of tadpoles of three species were collected to compare habitat use. This three species assemblage breed in the following order (first to last): Smilisca baudinii, Gastrophryne usta, and Rana berlandieri. R. berlandieri had the greatest microhabitat breadth followed by S. baudinii. S. baudinii and G. usta had high microhabitat overlap, but significant differences in microhabitat use were found. S. baudinii tended to occur near the bottom, while G. usta was near the surface. This study shows that temporal and habitat partitioning both occur and depend on the species of tadpole. Dynamic interactions occur between habitat and temporal dimensions. Phenology and habitat selection depend both on the species and on abiotic and biotic factors

    An effective two-stage simulated annealing algorithm for the minimum linear arrangement problem

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    In this paper, an improved two-stage simulated annealing algorithm is presented for the minimum linear arrangement problem for graphs. This algorithm integrates several distinguished features including an efficient heuristic to generate good quality initial solutions, a highly discriminating evaluation function, a special neighborhood function and an effective cooling schedule. The algorithm is evaluated on a set of 30 well-known benchmark instances of the literature and compared with several state-of-the-art algorithms, showing improvements of 17 previous best results

    An improved simulated annealing algorithm for bandwidth minimization

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    In this paper, a simulated annealing algorithm is presented for the bandwidth minimization problem for graphs. This algorithm is based on three distinguished features including an original internal representation of solutions, a highly discriminating evaluation function and an effective neighborhood. The algorithm is evaluated on a set of 113 well-known benchmark instances of the literature and compared with several state-of-the-art algorithms, showing improvements of some previous best results

    Constraining scalar-tensor quintessence by cosmic clocks

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    Scalar-tensor quintessence models can be constrained by identifying suitable cosmic clocks which allow to select confidence regions for cosmological parameters. In particular, we constrain the characterizing parameters of non-minimally coupled scalar-tensor cosmological models which admit exact solutions of the Einstein field equations. Lookback time to galaxy clusters at low intermediate, and high redshifts is considered. The high redshift time-scale problem is also discussed in order to select other cosmic clocks such as quasars.Comment: 13 pages, 8 figures. to be published in Astron & Astrop

    Preferences, use of and satisfaction with mental health services among a sample of Puerto Rican cancer patients

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    OBJECTIVE: The purpose of this study was to describe the preferences, the use, satisfaction of mental health services (MHS) among a sample of Puerto Rican patients with cancer undergoing oncology treatment. METHODS: A convenience sample of 120 patients diagnosed with cancer was recruited. Self-report questionnaires assessed socio-demographic and background questions, and the Mental Health Service Preference, Utilization and Satisfaction Questionnaire (MHSPUS). The Socio-demographic and Background Questionnaire inquired about participants\u27 demographic and socioeconomic characteristics, and included questions such as history of psychiatric diagnosis and spiritual practices. Univariate and Chi square analyses were used for descriptive purposes. Logistic regressions were used to explore associations between sociodemographic factors and MHS preferences and use. RESULTS: The majority of the sample were females (53.8%), 61 and older (53.8%), and married or living with partner (57.1%), and reported an income equal to or less than $12,000 per year (44.4%), which places them under the US federal poverty line. Most of the participants (66.7%) reported being receptive to seeking services. Findings showed a significant association between living situation and past (p \u3c .05) and lifetime use (p \u3c .05) of MHS and past use of MHS. Participants living alone were more like to have used MHS in the past and during their lifetime. Adjusted logistic regression analyses revealed that living with someone was a protective factor for not using MHS in their lifetime (OR = 0.28; C1 = 0.08-0.95). Participants preferred to receive MHS at the oncology clinic, preferably on the date of their oncology appointments and during morning hours. CONCLUSION: Findings support the integration of mental health services within the oncology practice setting

    Epigenetic regulation of human cancer/testis antigen gene, HAGE, in chronic myeloid leukemia

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    Cancer testis antigens (CTA) provide attractive targets for cancer-specific immunotherapy. Although CTA genes are expressed in some normal tissues, such as the testis, this immunologically protected site lacks MHC I expression and as such, does not present self antigens to T cells. To date, CTA genes have been shown to be expressed in a range of solid tumors via demethylation of their promoter CpG islands, but rarely in chronic myeloid leukemia (CML) or other hematologic malignancies
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