11,230 research outputs found
The validity of the Youth Physical Activity Questionnaire in 12-13 year old Scottish adolescents
Background: The development of accurate methods to measure health-behaviours forms an integral component in behavioural epidemiology. Population surveillance of physical activity often relies on self/proxy reported questionnaires due to cost and relative ease of administration. The aim of this study was to examine the criterion validity and measurement agreement between the Youth Physical Activity Questionnaire (YPAQ) and accelerometry before being included in a Scotland-wide study.
Methods: Forty four participants (12–13 years old; 61% girls) completed the YPAQ following 7 days wearing the Actigraph GT3X+. Mean moderate-to-vigorous physical activity (MVPA) per day was derived from YPAQ and accelerometer and validity was assessed using Spearman's correlation; Bland-Altman plots examined absolute agreement between methods.
Results: Pearson's and Spearman’s correlations between YPAQ and accelerometer were r = 0.47 and rs = 0.39 (p<0.01) respectively. The YPAQ over reported mean MVPA by 25.6 ± 50.2 minutes (95% CI 10.4-40.9 minutes; p <0.001), with 95% limits of agreement of −72.69 minutes and + 123.99 minutes. Evidence of underreporting at lower levels of activity and over reporting at higher levels of activity was evident (Pearson's r=0.81), in addition to heteroscedasticity, where variances increased as MVPA increased.
Conclusions: Although a moderate correlation between the two methods was apparent, the YPAQ should not be used interchangeably with accelerometry. The YPAQ does demonstrate a reasonable ability to rank MVPA, although it tends to under-report lower levels and over-report higher levels. This, and other administering factors, should be taken into consideration if being used for group or individual level analyses
A Critical Bricoleur Assumes Positive Intent: \u3ci\u3ePablito\u27s Problem\u3c/i\u3e
This dissertation serves to further critical theory research through bricolage autoethnography of a Latinx English teacher from the Rio Grande Valley of Texas. The bricolage functions to unify reflective constructs that expose an emancipatory catharsis and painful reacquaintance with individual and cultural identity. This project offers the concept of a happening as a construct embedded with the ongoing, reflective, and liberating critical consciousness process. Four happenings are offered and establish that the dichotomies of oppression and liberation, how they happened, are happening or may happen are not easily recognizable unless critical introspection is involved. The leading happening titled Pablito’s Problem chronicles the first recollection of oppression as a prepubescent. Followed by the second happening titled The Monkey—set during the \u2770s and \u2780 through secondary education, Jesús Mil Veces—looks at family traditions, and followed by fear—which narrates the occasions as an adult that challenge the tendency towards positive intent. Ultimately, the analysis of the four happenings identifies four critical consciousness moments as serendipitous results that, while struggling to maintain the fundamental notion of compassion, follow the critical pedagogy mantra
Second order effects in RC columns: comparative analysis of design approaches
The objective of this project is to analyze different design approaches for RC
columns, in particular those cases in which second order effects should be
considered when the column is under compression.
Throughout the study, a variety of support cases and different types of section
will be presented for columns of different slenderness ratios. These cases will
be resolved using the Simplified Methods provided in Eurocode 2 and the
evolution of second order effects with the slenderness ratio will be studied.
Within this study, the influence of creep, area of reinforcement and area of
concrete in the second order moment will be investigated, to then discern the
differences between the Nominal Stiffness and the Nominal Curvature methods.
It will be determined that in the Nominal Stiffness method creep has an
increasing effect as the slenderness ratio increments. Creep will have an effect
in the Nominal Curvature method until a certain slenderness value is achieved,
which depends on the compressive characteristic strength.
When studying the influence of the areas of reinforcement and concrete in
taking into account second order effects, it will also be deduced that increasing
the area of reinforcement is a good solution if the slenderness only just exceeds
the slenderness limit. If the slenderness is much higher than the limit, then it is
better to increase the area of concrete since it will increase the limit and reduce
the slenderness more effectively.
The differences found between the three types of sections will also be a subject
of study. These sections will be rectangular with reinforcement placed in
opposite sides, rectangular with uniform distribution of reinforcement and
circular with uniform distribution of reinforcement. The first section is the least
affected by second order effects whilst the second section is the most affected.
For the calculations, a tool in the form of a spreadsheet for the Simplified
Methods will be created with the purpose of being intuitive to use and generate
output values automatically.
Finally, columns of different slenderness ratios will be modeled and tested by
means of a finite element (FEM) analysis. The results of the evolution of the
second order moment with the slenderness ratio will be compared to those
obtained through the Simplified Methods and will prove to be quite similar
Staphylococcus aureus enterotoxin B regulates prostaglandin E-2 synthesis, growth, and migration in nasal tissue fibroblasts
Background. Superantigens and eicosanoids are important amplifiers and regulators of inflammation in airway diseases. We therefore studied the possible influence of Staphylococcus aureus enterotoxin B ( SEB) on the cyclooxygenase ( COX) pathway and basic functions of airway structural cells.
Methods. Fibroblasts were isolated from nasal inferior turbinate tissue and cultured in the presence of different concentrations of SEB. Preincubation with interferon ( IFN)-gamma was performed to induce expression of major histocompatibility complex ( MHC) class II receptors. Prostaglandin E2 ( PGE(2)) production was assayed by enzyme-linked immunosorbent assay, and levels of COX-2 and prostanoid E receptors 1-4 ( EP1-4) were assayed by real-time polymerase chain reaction. Migration and growth tests were performed, and SEB was localized within the cells by confocal microscopy.
Results. Stimulation with IFN-gamma and SEB significantly down-regulated PGE2, COX-2, and EP2 expression but not EP1, EP3, or EP4 expression. The enterotoxin blocked cell growth but increased the fibroblast migration rate. SEB was localized within the cell in the presence and absence of MHC-II, suggesting that mechanisms other than conventional binding may allow the enterotoxin to enter the cell.
Conclusions. These findings may have major implications for our understanding of the role played by bacterial superantigens in regulating the inflammatory and remodeling mechanisms of upper airway diseases and hence may help elucidate the pathophysiology of these diseases
Scientific Objectives for UV/Visible Astrophysics Investigations: A Summary of Responses by the Community (2012)
Following several recommendations presented by the Astrophysics Decadal
Survey 2010 centered around the need to define "a future ultraviolet-optical
space capability," on 2012 May 25, NASA issued a Request for Information (RFI)
seeking persuasive ultraviolet (UV) and visible wavelength astrophysics science
investigations. The goal was to develop a cohesive and compelling set of
science objectives that motivate and support the development of the next
generation of ultraviolet/visible space astrophysics missions. Responses were
due on 10 August 2012 when 34 submissions were received addressing a number of
potential science drivers. A UV/visible Mission RFI Workshop was held on 2012
September 20 where each of these submissions was summarized and discussed in
the context of each other. We present a scientific analysis of these
submissions and presentations and the pursuant measurement capability needs,
which could influence ultraviolet/visible technology development plans for the
rest of this decade. We also describe the process and requirements leading to
the inception of this community RFI, subsequent workshop and the expected
evolution of these ideas and concepts for the remainder of this decade.Comment: 22 pages, 1 figure, 3 table
The Geometry of Isochrone Orbits: from Archimedes' parabolae to Kepler's third law
In classical mechanics, the Kepler potential and the Harmonic potential share
the following remarkable property: in either of these potentials, a bound test
particle orbits with a radial period that is independent of its angular
momentum. For this reason, the Kepler and Harmonic potentials are called
\it{isochrone}. In this paper, we solve the following general problem: are
there any other isochrone potentials, and if so, what kind of orbits do they
contain? To answer these questions, we adopt a geometrical point of view
initiated by Michel H\'enon in 1959, in order to explore and classify
exhaustively the set of isochrone potentials and isochrone orbits. In
particular, we provide a geometric generalization of Kepler's third law, and
give a similar law for the apsidal angle, for any isochrone orbit. We also
relate the set of isochrone orbits to the set of parabolae in the plane under
linear transformations, and use this to derive an analytical parameterization
of any isochrone orbit. Along the way we compare our results to known ones,
pinpoint some interesting details of this mathematical physics problem, and
argue that our geometrical methods can be exported to more generic orbits in
potential theory.Comment: 54 pages, 18 figure
Kernels for Feedback Arc Set In Tournaments
A tournament T=(V,A) is a directed graph in which there is exactly one arc
between every pair of distinct vertices. Given a digraph on n vertices and an
integer parameter k, the Feedback Arc Set problem asks whether the given
digraph has a set of k arcs whose removal results in an acyclic digraph. The
Feedback Arc Set problem restricted to tournaments is known as the k-Feedback
Arc Set in Tournaments (k-FAST) problem. In this paper we obtain a linear
vertex kernel for k-FAST. That is, we give a polynomial time algorithm which
given an input instance T to k-FAST obtains an equivalent instance T' on O(k)
vertices. In fact, given any fixed e>0, the kernelized instance has at most
(2+e)k vertices. Our result improves the previous known bound of O(k^2) on the
kernel size for k-FAST. Our kernelization algorithm solves the problem on a
subclass of tournaments in polynomial time and uses a known polynomial time
approximation scheme for k-FAST
Participation of an electric vehicle fleet to primary frequency control in France
International audienceUsing electric vehicles (EV) as distributed storage units could be a solution to take advantage of the good availability of EVs and reduce their total cost of ownership. The scientific literature features frequency control as one of the most profitable electric market for EV fleets. This paper presents an economic evaluation of the expected remuneration for a fleet of EVs participating to primary frequency control in France in 2020. First, the modelling of a French EV fleet is addressed. Simulations of the participation of this fleet to the French primary frequency control market are then performed. Two regulation strategies are considered: in the first one, only unidirectional power exchanges are allowed between EVs and the grid, while in the second one bidirectional exchanges are allowed. Results show that the expected remuneration is highly dependent on the ability to charge at work, the power level of the charging stations, and the bidirectional capabilities of the cars. Reference to this paper should be made as follows: Codani, P., Petit, M. and Perez, Y. (xxxx) 'Participation of an electric vehicle fleet to primary frequency control in France', Int
Participation d'une flotte de véhicules électriques au réglage primaire de fréquence
Tirer profit de la disponibilité des véhicules électriques (VE) et les utiliser comme moyen de stockage diffus pour le réseau électrique est une solution pour diminuer le coût de cycle de vie élevé de ces derniers. La littérature présente le réglage de fréquence comme la solution la plus profitable pour les véhicules électriques. Ce papier propose une évaluation des gains économiques potentiels pour une flotte de véhicules électriques participant au réglage primaire, dans le cas Français. Dans un premier temps, le comportement d'une flotte de VE est modélisé. La participation de cette flotte au réglage primaire de fréquence est ensuite simulée. Deux stratégies de réglage, une avec échanges de puissance bidirectionnels entre les véhicules et le réseau, et une avec échanges unidirectionnels, sont comparées. Les résultats fournissent des indications sur la taille idéale de la flotte, et sur la caractérisation des échanges de puissance avec le réseau
A developmental model for the pathogenenesis of cardiac arterio-ventricular fistulae
Coronary Artery Fistulae (CAF) are congenital coronary artery (CA) anomalies consisting of an abnormal communication of a coronary artery with either a cardiac chamber or a large cardiac vessel. Although their incidence in the Western population is low, CAF can lead to complications such as myocardial hypertrophy, endocarditis, heart dilatation and cardiac failure. CAFs can appear as an isolated anomaly or linked to some other forms of congenital heart disease like Left Ventricular Non-Compaction (LVNC) and intrinsic CA anatomy anomalies, but their etiology remains unknown. In this work we have used two different experimental models (transgenic mice and avian embryos) to investigate on the developmental mechanics of CAF formation. In order to tackle this goal, we have manipulated epicardial development and ventricular wall compaction, two inextricably related developmental events during coronary embryogenesis. Conditional integrin α4 gene deletion in the septum transversum/proepicardial (ST/PE) region (G2-Gata4+) disrupts early epicardium development and reduces cardiomyocyte proliferation, leading to the thinning of the ventricular compact myocardial layer. Reduction in compact myocardium thickness associates to the presence of multiple ventricular myocardial discontinuities and focal endocardial extrusion. This same phenotype can be experimentally reproduced in chick embryos using a cryocauterization method (Palmquist-Gomes et al., 2016). Our results suggest that the partial absence of epicardium in α4integrin;G2-Gata4Cre mouse embryos and the cryoinjury in avian embryos generate myocardial discontinuities in the embryonic ventricular wall, which promote endocardial extrusion towards the pericardial cavity and the early contact of the endocardium with coronary progenitors at the epicardial surface of the heart. In the case of avian embryos, this phenomenon leads to precocious smooth muscle differentiation from epicardial mesenchymal cells, and the formation of pouch-like structures that closely resemble CAF. We conclude that anomalous compact myocardial embryonic growth can originate CAF.Universidad de Málaga. Campus de Excelencia Internacional AndalucÃa Tech
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