332 research outputs found
Vallerand´s model in Asturian adolescents: Implementation and development
Se examinó la secuencia del modelo de Vallerand (1997) en el contexto
de la educación fÃsica: Los factores sociales influyen en los mediadores
psicológicas, que a su vez predicen los tipos de motivación, que dan lugar a
determinadas consecuencias. Tomando como base el Modelo de Vallerand y el
estudio empÃrico de Ntoumanis (2001), este trabajo se propuso comprobar el
modelo completo en todas sus secuencias con una muestra de estudiantes
adolescentes asturianos (N=507) de una franja de edad más amplia (12-17
años), incluyendo como factor social una subdimensión distinta al trabajo original
(papel importante) e introduciendo dos nuevas consecuencias motivacionales (diversión y grado de presión percibida). Se administraron versiones españolas
de diversos cuestionarios: PMCSQ-2, BPNES, PLOC, IMI (diversión, esfuerzo
percibido y presión percibida) y consecuencias motivacionales (aburrimiento e
intención de práctica). El análisis factorial confirmatorio reveló que los datos se
ajustaban bien al modelo, y que las tres necesidades psicológicas mediaban
entre el clima de tarea y la motivación intrÃnseca. Ésta predijo positivamente la
diversión, el esfuerzo e intención de práctica, y negativamente, el aburrimiento.
La competencia percibida resultó el predictor más fuerte, influyendo
positivamente en la motivación más autónoma y, negativamente, en la más
controlada. La desmotivación predijo positivamente el aburrimiento y la presión
y, negativamente, el esfuerzoThe complete sequence of Vallerand’s model (1997) was examined in the
context of physical education: Social factors influence the psychological
mediators, which in turn predicted motivation types, which lead to certain
consequences. Based on the Vallerand´s Model and Ntoumanis (2001)
empirical study, this investigation was undertaken to test the full model in all
sequences with a sample of Asturian adolescents students (N = 507) of a wider
age range (12 -17 years), including as a social factor a distinct sub-dimension to
the original work (relevant role) and introducing two new motivational
consequences (fun and degree of perceived pressure). The Spanish validated
version of these questionnaires was used: PMCSQ-2, BPNES, PLOC, three
subscales of IMI (enjoyment, effort, and competence) and other motivational
outcomes such as boredom and future sport participation. Results from the
Confirmatory Factor Analysis showed that the data fit the model proposed, and
the three psychological needs mediated between the task climate and the
intrinsic motivation. This positively predicted enjoyment, effort and future sport
participation, and negatively boredom. Competence was the stronger predictor,
positively influencing the most autonomous types of motivation, and negatively
the more controlled ones. Amotivation positively predicted boredom and
pressure, and negatively, effortEste estudio se ha realizado en el marco del proyecto de I+D+I número DEP2012-
31997, subvencionado por el Ministerio de EconomÃa y Competitivida
Evaluation of the presence of Vibrio parahaemolyticus in white shrimp (Litopenaeus vannamei) estuarine-wild from southern Sinaloa and northern Nayarit by microbiological analysis and PCR
Given the incidence of human poisonings attributed
to raw shrimp consumption in southern of Sinaloa
and northern of Nayarit in recent years, white shrimp
(Litopenaeus vannamei) was sampled from three wildestuaries
where it’s been captured and one sample was
taken from a sale center in order to determine the possible
presence of toxigenic Vibrio parahaemolyticus, from May to
December of 2012. Samples were analyzed by Biochemical
test and Polymerase Chain Reaction (PCR), they were
also tested for the specific an toxicological identification,
using molecular oligo nucleotides markers tlh, tdh and trh.
The number of positives results were recorded to a table of
most probable number (MPN).The number of samples positive
for V. parahaemolyticus, weren’t toxigenic and it was
demonstrated that they were below the limit established
in the Mexican Official Standard NOM-242-SSA1-2009. In
conclusion, the present study revealed that consumption of
raw shrimp from the dates and sites sampled did not show
to be a risk for human gastrointestinal diseases
Chaotic Electron Motion in Superlattices. Quantum-Classical Correspondence of the Structure of Eigenstates and LDOS
We investigate the classical-quantum correspondence for particle motion in a
superlattice in the form of a 2D channel with periodic modulated boundaries.
Its classical dynamics undergoes the generic transition to chaos of Hamiltonian
systems as the amplitude of the modulation is increased. We show that for
strong chaotic motion, the classical counterpart of the structure of
eigenstates (SES) in energy space reveals an excellent agreement with the
quantum one. This correspondence allows us to understand important features of
the SES in terms of classical trajectories. We also show that for typical 2D
modulated waveguides there exist, at any energy range, extremely localized
eigenstates (in energy) which are practically unperturbed by the modulation.
These states contribute to the strong fluctuations around the classical SES.
The approach to the classical limit is discussed.Comment: 4 pages, 4 figure
Effect of high-pressure processing of Atlantic mackerel (Scomber scombrus) on biochemical changes during commercial frozen storage
This research focuses on biochemical changes related to quality losses observed in Atlantic mackerel (Scomber scombrus) muscle stored under commercial frozen storage conditions (9 months, −18 °C) when subjected to highhydrostatic pressure (HHP) treatments (125, 150, 175, and 200 MPa for 0 min) before freezing. After freezing, free fatty acid (FFA) formation (lipid hydrolysis assessment) showed a marked inhibition in HHP-treated fish and during frozen storage of samples treated at 175 MPa. Fluorescence ratio (FR) assessment of tertiary lipid oxidation showed a partial inhibitory effect during the 0–9-month period for samples treated at 175 and 200 MPa. After a 3-month storage of samples treated at these pressure levels, one-dimensional SDS-PAGE analysis of the sarcoplasmic protein fraction revealed the disappearance of a band; additionally, samples treated at 150 MPa showed the same effect at month 9. After gel excision, trypsin
digestion, tandem mass spectrometry (MS/MS), and sequence database analysis, the band was identified as phosphoglycerate mutase 2 (28.7 kDa). On the other hand, HHP processing did not show a significant effect on trimethylamine (TMA) values, primary and secondary lipid oxidation, PUFA levels, 1-D myofibril protein pattern, and the activity of acid phosphatase and cathepsins B and D. Biochemical quality indices such as FFA, TMA, and FR and the activity of acid phosphatase and cathepsin B showed a progressive increase throughout the frozen storage of all samples
Lipid and protein changes related to quality loss in frozen sardine (Sardina pilchardus) previously processed under high-pressure conditions
This research focuses on biochemical changes related to quality loss in frozen (−18 °C for 9 months) sardine
(Sardina pilchardus) previously subjected to high-pressure (HP) processing (125–200 MPa). The inhibition (p < 0.05) of lipid hydrolysis development (lower free fatty acid formation and lipase activity), observed in frozen sardine as a result of the previous HP treatment, increased with the pressure level applied. Several parameters including peroxide value, thiobarbituric acid index, fluorescent compounds, and polyenes
showed that the applied HP conditions prior to sardine freezing did not increase lipid oxidation. Also, HP did not induce a substantial modification of acid phosphatase and cathepsins B and D activities, and the electrophoretic patterns of sarcoplasmic and myofibrillar protein fractions did not change. However, HP processing led to a decrease in myofibrillar protein content in frozen pressure-treated fish, an effect that was
higher in 175- and 200-MPa treated samples. In conclusion, this research showed that pressure treatments in the 125–200- MPa range with holding time of 0 min cause only minor modifications in biochemical indicators of deterioration throughout the subsequent frozen storage of samples for up to 9 months. This study shows the need to optimize HP conditions, particularly in the case of applications combining HP treatments, frozen storage, and thawing to obtain products with high quality and commercial viability
Quantum-classical correspondence for local density of states and eigenfunctions of a chaotic periodic billiard
Classical-quantum correspondence for conservative chaotic Hamiltonians is
investigated in terms of the structure of the eigenfunctions and the local
density of states, using as a model a 2D rippled billiard in the regime of
global chaos. The influence of the observed localized and sparsed states in the
quantum-classical correspondence is discussed.Comment: 8 pages, 4 figure
Spectral and localization properties of random bipartite graphs
Bipartite graphs are often found to represent the connectivity between the components of many systems such as ecosystems. A bipartite graph is a set of n nodes that is decomposed into two disjoint subsets, having m and n-m vertices each, such that there are no adjacent vertices within the same set. The connectivity between both sets, which is the relevant quantity in terms of connections, can be quantified by a parameter a ¿ [0, 1] that equals the ratio of existent adjacent pairs over the total number of possible adjacent pairs. Here, we study the spectral and localization properties of such random bipartite graphs. Specifically, within a Random Matrix Theory (RMT) approach, we identify a scaling parameter ¿ = ¿(n, m, a) that fixes the localization properties of the eigenvectors of the adjacency matrices of random bipartite graphs. We also show that, when ¿ 10) the eigenvectors are localized (extended), whereas the localization–to–delocalization transition occurs in the interval 1/10 < ¿ < 10. Finally, given the potential applications of our findings, we round off the study by demonstrating that for fixed ¿, the spectral properties of our graph model are also universal
Higgs triplet effects in purely leptonic processes
We consider the effect of complex Higgs triplets on purely leptonic processes
and survey the experimental constraints on the mass and couplings of their
single and double charge members. Present day experiments tolerate values of
the Yukawa couplings of these scalars at the level of the standard electroweak
gauge couplings. We show that the proposed measurement of the ratio
R_{LCD}=\sigma (\nu_{\mu}e)/ [\sigma (\bb\nu_{\mu}e) + \sigma (\nu_e e )]
would allow to explore a large region of the parameter space inaccessible to
the usual ratio R=\sigma (\nu_{\mu}e)/\sigma (\bb\nu_{\mu}e).Comment: 14 pages, LaTeX, Three figures included using uufiles. A postscript
version is available at ftp://ftp.ifae.es/preprint/ft/uabft378.p
Experiencia en el tratamiento quirúrgico del angiofibroma nasal juvenil en Hospital de Especialidades No 2 Lic. Luis Donaldo Colosio Murrieta. Instituto Mexicano del Seguro Social de Ciudad Obregón, Sonora
Objective: To present our experience and assess the recurrence of juvenile nasopharyngeal angiofibroma after a surgical
treatment (open versus endoscopic approach) in the country’s northwestern Department of Otorhinolaryngology.
Materials and methods: An observational, retrospective, analytical study. The medical records of patients diagnosed
with juvenile nasopharyngeal angiofibroma, who were treated at the Department of Otorhinolaryngology – Head and Neck
Surgery of this institution from 2014 to 2017, were reviewed.
Results: A total of 19 patients diagnosed with juvenile nasopharyngeal angiofibroma underwent a surgical procedure, out
of which 14 had an open surgery and 5 an endoscopic one. Recurrence accounted for 50 % and 40 %, respectively, which
was not statistically significant (p = 0.88). However, other variables were compared, such as the need for admission to the
Intensive Care Unit (ICU), which was represented by 71 % in the case of the open approach and 20 % for the endoscopic
approach, where a significant difference was found (p = 0.04).
Conclusions: The study shows no statistically significant advantage of the endoscopic approach versus the open approach,
but demonstrates less need for ICU admissions, which would reduce healthcare costs
- …