1,568 research outputs found
Histological evidence for a supraspinous ligament in sauropod dinosaurs
Supraspinous ossified rods have been reported in the sacra of some derived sauropod dinosaurs. Although different hypotheses have been proposed to explain the origin ofthis structure, histological evidence has never been provided to support or reject any of them. In order to establish its origin, we analyse and characterize the microstructure of thesupraspinous rod of two sauropod dinosaurs from the Upper Cretaceous of Argentina. The supraspinous ossified rod is almost entirely formed by dense Haversian bone. Remains ofprimary bone consist entirely of an avascular tissue composed of two types of fibre-like structures, which are coarse and longitudinally (parallel to the main axis of the element) oriented. These structures are differentiated on the basis of their optical properties under polarized light. Very thin fibrous strands are also observed in some regions. These small fibres are all oriented parallel to one another but perpendicular to the element main axis. Histological features of the primary bone tissue indicate that the sacral supraspinous rod corresponds to an ossified supraspinous ligament. The formation of this structure appears to have been a non-pathological metaplastic ossification, possibly induced by the continuous tensile forces applied to the element.Fil: Cerda, Ignacio Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; Argentina. Universidad Nacional de Río Negro; ArgentinaFil: Casal, Gabriel. Universidad Nacional de la Patagonia; ArgentinaFil: Martínez, Rubén Darío. Universidad Nacional de la Patagonia ; ArgentinaFil: Ibiricu, Lucio Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentin
Cross-cultural psychometric assessment of an appetite questionnaire for patients with cancer
Objective: To evaluate the psychometric properties, along with
cross-cultural invariance analysis, of the Cancer Appetite and
Symptom Questionnaire (CASQ).
Method: Data from 555 United Kingdom (UK) cancer patients
were used to evaluate the psychometric properties of the CASQ.
Construct validity was assessed through factorial and convergent
validity. We conducted a confirmatory factor analysis using as
indices the chi-square ratio by degrees of freedom (χ2/df), the
comparative fit index (CFI), the goodness of fit index (GFI),
and the root mean square error of approximation (RMSEA).
Convergent validity was estimated by the items’ average
variance extracted (AVE). Reliability was estimated by composite
reliability and internal consistency. Factorial invariance analysis
of the CASQ was evaluated by multigroup analysis (∆χ2) using
the UK and Brazilian samples.
Results: All items showed adequate psychometric sensitivity in
the UK sample. One item was removed and four correlations
were included between errors with an appropriate fit of the model
(χ2/df = 2.674, CFI = 0.966, GFI = 0.964, RMSEA = 0.055).
The reliability of the CASQ was adequate and the convergent
validity was low. The factorial structure of the CASQ differed
across countries, and a lack of measurement invariance for the
two countries was observed (λ: ∆χ2 = 64.008, p < 0.001; i: ∆χ2 =
3515.047, p < 0.001; Res: ∆χ2 = 4452.504, p < 0.001).
Conclusion: The CASQ showed adequate psychometric
properties in the UK sample. The ability to estimate loss of
appetite and the presence of symptoms was different between
UK and Brazilian patients
Variations of training load, monotony, and strain and dose-response relationships with maximal aerobic speed, maximal oxygen uptake, and isokinetic strength in professional soccer players
This study aimed to identify variations in weekly training load, training monotony, and training strain across a 10-week period (during both, pre- and in-season phases); and to analyze the dose-response relationships between training markers and maximal aerobic speed (MAS), maximal oxygen uptake, and isokinetic strength. Twenty-seven professional soccer players (24.9±3.5 years old) were monitored across the 10-week period using global positioning system units. Players were also tested for maximal aerobic speed, maximal oxygen uptake, and isokinetic strength before and after 10 weeks of training. Large positive correlations were found between sum of training load and extension peak torque in the right lower limb (r = 0.57, 90%CI[0.15;0.82]) and the ratio agonist/antagonist in the right lower limb (r = 0.51, [0.06;0.78]). It was observed that loading measures fluctuated across the period of the study and that the load was meaningfully associated with changes in the fitness status of players. However, those magnitudes of correlations were small-to-large, suggesting that variations in fitness level cannot be exclusively explained by the accumulated load and loading profile
Stochastic Gravity: Theory and Applications
Whereas semiclassical gravity is based on the semiclassical Einstein equation
with sources given by the expectation value of the stress-energy tensor of
quantum fields, stochastic semiclassical gravity is based on the
Einstein-Langevin equation, which has in addition sources due to the noise
kernel.In the first part, we describe the fundamentals of this new theory via
two approaches: the axiomatic and the functional. In the second part, we
describe three applications of stochastic gravity theory. First, we consider
metric perturbations in a Minkowski spacetime: we compute the two-point
correlation functions for the linearized Einstein tensor and for the metric
perturbations. Second, we discuss structure formation from the stochastic
gravity viewpoint. Third, we discuss the backreaction of Hawking radiation in
the gravitational background of a quasi-static black hole.Comment: 75 pages, no figures, submitted to Living Reviews in Relativit
Radiative contribution to neutrino masses and mixing in SSM
In an extension of the minimal supersymmetric standard model (popularly known
as the SSM), three right handed neutrino superfields are introduced to
solve the -problem and to accommodate the non-vanishing neutrino masses
and mixing. Neutrino masses at the tree level are generated through parity
violation and seesaw mechanism. We have analyzed the full effect of one-loop
contributions to the neutrino mass matrix. We show that the current three
flavour global neutrino data can be accommodated in the SSM, for both
the tree level and one-loop corrected analyses. We find that it is relatively
easier to accommodate the normal hierarchical mass pattern compared to the
inverted hierarchical or quasi-degenerate case, when one-loop corrections are
included.Comment: 51 pages, 14 figures (58 .eps files), expanded introduction, other
minor changes, references adde
Cancer Appetite and Symptom Questionnaire (CASQ) for Brazilian Patients: Cross-Cultural Adaptation and Validation Study
Background
Appetite and symptoms, conditions generally reported by the patients with cancer, are
somewhat challenging for professionals to measure directly in clinical routine (latent conditions).
Therefore, specific instruments are required for this purpose. This study aimed to perform
a cultural adaptation of the Cancer Appetite and Symptom Questionnaire (CASQ), into
Portuguese and evaluate its psychometric properties on a sample of Brazilian cancer
patients.
Methods
This is a validation study with Brazilian cancer patients. The face, content, and construct
(factorial and convergent) validities of the Cancer Appetite and Symptom Questionnaire,
the study tool, were estimated. Further, a confirmatory factor analysis (CFA) was conducted.
The ratio of chi-square and degrees of freedom (χ2
/df), comparative fit index (CFI),
goodness of fit index (GFI) and root mean square error of approximation (RMSEA) were
used for fit model assessment. In addition, the reliability of the instrument was estimated
using the composite reliability (CR) and Cronbach’s alpha coefficient (α), and the invariance
of the model in independent samples was estimated by a multigroup analysis (Δχ2).
Results
Participants included 1,140 cancer patients with a mean age of 53.95 (SD = 13.25) years;
61.3% were women. After the CFA of the original CASQ structure, 2 items with inadequate
factor weights were removed. Four correlations between errors were included to provide
adequate fit to the sample (χ2
/df = 8.532, CFI = .94, GFI = .95, and RMSEA = .08). Themodel exhibited a low convergent validity (AVE = .32). The reliability was adequate
(CR = .82 α = .82). The refined model showed strong invariance in two independent samples
(Δχ2
: λ: p = .855; i: p = .824; Res: p = .390). A weak stability was obtained between
patients undergoing chemotherapy and radiotherapy (Δχ2
: λ: p = .155; i: p < .001; Res:
p < .001), and between patients undergoing chemotherapy combined with radiotherapy
and palliative care (Δχ2
: λ: p = .058; i: p < .001; Res: p < .001).
Conclusion
The Portuguese version of the CASQ had good face and construct validity and reliability.
However, the CASQ still presented invariance in independent samples of Brazilian patients
with cancer. However, the tool has low convergent validity and weak invariance in samples
with different treatment
Differential cell line susceptibility to the emerging Zika virus: implications for disease pathogenesis, non-vector-borne human transmission and animal reservoirs
published_or_final_versio
Stochastic Gravity: Theory and Applications
Whereas semiclassical gravity is based on the semiclassical Einstein equation
with sources given by the expectation value of the stress-energy tensor of
quantum fields, stochastic semiclassical gravity is based on the
Einstein-Langevin equation, which has in addition sources due to the noise
kernel. In the first part, we describe the fundamentals of this new theory via
two approaches: the axiomatic and the functional. In the second part, we
describe three applications of stochastic gravity theory. First, we consider
metric perturbations in a Minkowski spacetime, compute the two-point
correlation functions of these perturbations and prove that Minkowski spacetime
is a stable solution of semiclassical gravity. Second, we discuss structure
formation from the stochastic gravity viewpoint. Third, we discuss the
backreaction of Hawking radiation in the gravitational background of a black
hole and describe the metric fluctuations near the event horizon of an
evaporating black holeComment: 100 pages, no figures; an update of the 2003 review in Living Reviews
in Relativity gr-qc/0307032 ; it includes new sections on the Validity of
Semiclassical Gravity, the Stability of Minkowski Spacetime, and the Metric
Fluctuations of an Evaporating Black Hol
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Distribution of mosquitoes in the South East of Argentina and first report on the analysis based on 18S rDNA and COI sequences
Although Mar del Plata is the most important city on the Atlantic coast of Argentina, mosquitoes inhabiting such area are almost uncharacterized. To increase our knowledge in their distribution, we sampled specimens of natural populations. After the morphological identification based on taxonomic keys, sequences of DNA from small ribosomal subunit (18S rDNA) and cytochrome c oxidase I (COI) genes were obtained from native species and the phylogenetic analysis of these sequences were done. Fourteen species from the genera Uranotaenia, Culex, Ochlerotatus and Psorophora were found and identified. Our 18S rDNA and COI-based analysis indicates the relationships among groups at the supra-species level in concordance with mosquito taxonomy. The introduction and spread of vectors and diseases carried by them are not known in Mar del Plata, but some of the species found in this study were reported as pathogen vectors
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