514 research outputs found

    The Number of Cultural Traits Is Correlated with Female Group Size but Not with Male Group Size in Chimpanzee Communities

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    What determines the number of cultural traits present in chimpanzee (Pan troglodytes) communities is poorly understood. In humans, theoretical models suggest that the frequency of cultural traits can be predicted by population size. In chimpanzees, however, females seem to have a particularly important role as cultural carriers. Female chimpanzees use tools more frequently than males. They also spend more time with their young, skewing the infants' potential for social learning towards their mothers. In Gombe, termite fishing has been shown to be transmitted from mother to offspring. Lastly, it is female chimpanzees that transfer between communities and thus have the possibility of bringing in novel cultural traits from other communities. From these observations we predicted that females are more important cultural carriers than males. Here we show that the reported number of cultural traits in chimpanzee communities correlates with the number of females in chimpanzee communities, but not with the number of males. Hence, our results suggest that females are the carriers of chimpanzee culture

    Prioritization strategies in clinical practice guidelines development: a pilot study

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    Objective: Few methodological studies address the prioritization of clinical topics for the development of Clinical Practice Guidelines (CPGs). The aim of this study was to validate a methodology for Priority Determination of Topics (PDT) of CPGs. Methods and results: Firstly, we developed an instrument for PDT with 41 criteria that were grouped under 10 domains, based on a comprehensive systematic search. Secondly, we performed a survey of stakeholders involved in CPGs development, and end users of guidelines, using the instrument. Thirdly, a pilot testing of the PDT procedure was performed in order to choose 10 guideline topics among 34 proposed projects; using a multicriteria analysis approach, we validated a mechanism that followed five stages: determination of the composition of groups, item/domain scoring, weights determination, quality of the information used to support judgments, and finally, topic selection. Participants first scored the importance of each domain, after which four different weighting procedures were calculated (including the survey results). The process of weighting was determined by correlating the data between them. We also reported the quality of evidence used for PDT. Finally, we provided a qualitative analysis of the process. The main domains used to support judgement, having higher quality scores and weightings, were feasibility, disease burden, implementation and information needs. Other important domains suc

    Transtorno autístico e doença celíaca : sem evidências de associação

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    Objective: To evaluate the possible association between celiac disease (CD) and/or gluten sensitivity (GS) and autism spectrum disorder (ASD). Methods: Occurrences of CD were determined in a group of children and adolescents affected by ASD and, conversely, occurrences of ASD were assessed in a group of biopsy-proven celiac patients. To detect the possible existence of GS, the levels of antigliadin antibodies in ASD patients were assessed and compared with the levels in a group of non-celiac children. Results: The prevalence of CD or GS in ASD patients was not greater than in groups originating from the same geographical area. Similarly the prevalence of ASD was not greater than in a group of biopsy-proven CD patients. Conclusion: No statistically demonstrable association was found between CD or GS and ASD. Consequently, routine screening for CD or GS in all patients with ASD is, at this moment, neither justifed nor cost-effective. ___________________________________________________________________________________ RESUMOObjetivo: Avaliar a possível associação entre doença celíaca (DC) e/ou sensibilidade ao glúten (SG) e transtorno do espectro autista (TEA). Métodos: Ocorrências de DC foram determinadas em um grupo de crianças e adolescentes afetados pelo TEA e a ocorrência d TEA foi avaliada em um grupo de pacientes com DC comprovada por biópsia. Para detectar a possível existência de SG, foram determinados níveis de anticorpos antigliadina em pacientes com TEA e comparados ao grupo de crianças sem a doença celíaca. Resultados: A prevalência de DC ou SG não foi maior no grupo de pacientes com TEA quando comparada a grupos de indivíduos originários da mesma região geográfca. De modo similar, a prevalência do TEA não foi maior ao ser comparada ao grupo de pacientes com DC. Conclusão: Não houve associação estatisticamente demonstrável entre DC ou SG e TEA. Consequentemente, não são justifcáveis, no momento, exames de rotina para detecção de DC ou SG em pacientes com TEA

    Diffractive Dijet Production at sqrt(s)=630 and 1800 GeV at the Fermilab Tevatron

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    We report a measurement of the diffractive structure function FjjDF_{jj}^D of the antiproton obtained from a study of dijet events produced in association with a leading antiproton in pˉp\bar pp collisions at s=630\sqrt s=630 GeV at the Fermilab Tevatron. The ratio of FjjDF_{jj}^D at s=630\sqrt s=630 GeV to FjjDF_{jj}^D obtained from a similar measurement at s=1800\sqrt s=1800 GeV is compared with expectations from QCD factorization and with theoretical predictions. We also report a measurement of the ξ\xi (xx-Pomeron) and β\beta (xx of parton in Pomeron) dependence of FjjDF_{jj}^D at s=1800\sqrt s=1800 GeV. In the region 0.035<ξ<0.0950.035<\xi<0.095, t<1|t|<1 GeV2^2 and β<0.5\beta<0.5, FjjD(β,ξ)F_{jj}^D(\beta,\xi) is found to be of the form β1.0±0.1ξ0.9±0.1\beta^{-1.0\pm 0.1} \xi^{-0.9\pm 0.1}, which obeys β\beta-ξ\xi factorization.Comment: LaTeX, 9 pages, Submitted to Phys. Rev. Letter

    Adrenal adenomatoid tumor in a patient with human immunodeficiency virus

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    We present the clinical course of a patient with human immunodeficiency virus and an adrenal adenomatoid tumor (AAT). We describe the clinical course and laboratory, radiographic, and microscopic findings of a patient with human immunodeficiency virus (HIV) and an adenomatoid tumor of the right adrenal gland. A review of the literature was also done via electronic searches through PubMed for articles from 1965 to 2008 that contained the following search terms, adenomatoid tumor limited to the English language only. A 22 year-old African-American male with HIV was incidentally found to have a hypermetabolic right adrenal mass. The patient underwent laparoscopic adrenalectomy and the mass had morphological and immunohistochemical features that were consistent with an AAT. A review of the medical literature reveals that almost all cases of AAT were in male patients (96%) with a mean age of 41±11 years (range=22–64) with no significant difference in laterality (right side=46%, left side=50%, unknown=4%). AAT have an average size of 4.2±3.5 cm (range=0.5–14.3 cm). Pre-operative imaging studies do not appear to be able to reliably distinguish AAT from other types of adrenocortical tumors. For reasons that require further research, AAT typically occur in male patients and may be associated with immunosuppression. AAT can be safely removed laparoscopically with no evidence of long-term recurrence even with tumor extension beyond the adrenal capsule

    A Study of B0 -> J/psi K(*)0 pi+ pi- Decays with the Collider Detector at Fermilab

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    We report a study of the decays B0 -> J/psi K(*)0 pi+ pi-, which involve the creation of a u u-bar or d d-bar quark pair in addition to a b-bar -> c-bar(c s-bar) decay. The data sample consists of 110 1/pb of p p-bar collisions at sqrt{s} = 1.8 TeV collected by the CDF detector at the Fermilab Tevatron collider during 1992-1995. We measure the branching ratios to be BR(B0 -> J/psi K*0 pi+ pi-) = (8.0 +- 2.2 +- 1.5) * 10^{-4} and BR(B0 -> J/psi K0 pi+ pi-) = (1.1 +- 0.4 +- 0.2) * 10^{-3}. Contributions to these decays are seen from psi(2S) K(*)0, J/psi K0 rho0, J/psi K*+ pi-, and J/psi K1(1270)

    Studying the Underlying Event in Drell-Yan and High Transverse Momentum Jet Production at the Tevatron

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    We study the underlying event in proton-antiproton collisions by examining the behavior of charged particles (transverse momentum pT > 0.5 GeV/c, pseudorapidity |\eta| < 1) produced in association with large transverse momentum jets (~2.2 fb-1) or with Drell-Yan lepton-pairs (~2.7 fb-1) in the Z-boson mass region (70 < M(pair) < 110 GeV/c2) as measured by CDF at 1.96 TeV center-of-mass energy. We use the direction of the lepton-pair (in Drell-Yan production) or the leading jet (in high-pT jet production) in each event to define three regions of \eta-\phi space; toward, away, and transverse, where \phi is the azimuthal scattering angle. For Drell-Yan production (excluding the leptons) both the toward and transverse regions are very sensitive to the underlying event. In high-pT jet production the transverse region is very sensitive to the underlying event and is separated into a MAX and MIN transverse region, which helps separate the hard component (initial and final-state radiation) from the beam-beam remnant and multiple parton interaction components of the scattering. The data are corrected to the particle level to remove detector effects and are then compared with several QCD Monte-Carlo models. The goal of this analysis is to provide data that can be used to test and improve the QCD Monte-Carlo models of the underlying event that are used to simulate hadron-hadron collisions.Comment: Submitted to Phys.Rev.

    Precision measurement of the top quark mass from dilepton events at CDF II

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    We report a measurement of the top quark mass, M_t, in the dilepton decay channel of ttˉb+νbˉνˉt\bar{t}\to b\ell'^{+}\nu_{\ell'}\bar{b}\ell^{-}\bar{\nu}_{\ell} using an integrated luminosity of 1.0 fb^{-1} of p\bar{p} collisions collected with the CDF II detector. We apply a method that convolutes a leading-order matrix element with detector resolution functions to form event-by-event likelihoods; we have enhanced the leading-order description to describe the effects of initial-state radiation. The joint likelihood is the product of the likelihoods from 78 candidate events in this sample, which yields a measurement of M_{t} = 164.5 \pm 3.9(\textrm{stat.}) \pm 3.9(\textrm{syst.}) \mathrm{GeV}/c^2, the most precise measurement of M_t in the dilepton channel.Comment: 7 pages, 2 figures, version includes changes made prior to publication by journa
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