673 research outputs found
Observables in 3-dimensional quantum gravity and topological invariants
In this paper we report some results on the expectation values of a set of
observables introduced for 3-dimensional Riemannian quantum gravity with
positive cosmological constant, that is, observables in the Turaev-Viro model.
Instead of giving a formal description of the observables, we just formulate
the paper by examples. This means that we just show how an idea works with
particular cases and give a way to compute 'expectation values' in general by a
topological procedure.Comment: 24 pages, 47 figure
Supernova search at intermediate z. I. Spectroscopic analysis
We study 8 supernovae discovered as part of the International Time Programme
(ITP) project ``Omega and Lambda from Supernovae and the Physics of Supernova
Explosions'' at the European Northern Observatory (ENO). The goal of the
project is to increase the sample of intermediate redshift (0.1<z<0.4) SNe Ia
for testing properties of SNe Ia along z and for enlarging the sample in the
Hubble diagram up to large z.Comment: 2 pages, 2 figures, 1 table, to appear in ``1604-2004: Supernovae as
Cosmological Lighthouses'', (extended text upon request
56Ni dredge-up in the type IIp Supernova 1995V
We present contemporary infrared and optical spectra of the plateau type II
SN 1995V in NGC 1087 covering four epochs, approximately 22 to 84 days after
shock breakout. The data show, for the first time, the infrared spectroscopic
evolution during the plateau phase of a typical type II event. In the optical
region P Cygni lines of the Balmer series and of metals lines were identified.
The infrared (IR) spectra were largely dominated by the continuum, but P Cygni
Paschen lines and Brackett gamma lines were also clearly seen. The other
prominent IR features are confined to wavelengths blueward of 11000 \AA and
include Sr II 10327, Fe II 10547, C I 10695 and He I 10830 \AA. We demonstrate
the presence of He I 10830 \AA on days 69 and 85. The presence of this line at
such late times implies re-ionisation. A likely re-ionising mechanism is
gamma-ray deposition following the radioactive decay of 56Ni. We examine this
mechanism by constructing a spectral model for the He I 10830 \AA line based on
explosion model s15s7b2f of Weaver & Woosley (1993). We find that this does not
generate the observed line owing to the confinement of the 56Ni to the central
zones of the ejecta. In order to reproduce the He I line, it was necessary to
introduce additional upward mixing of the 56Ni, with 10^{-5} of the total
nickel mass reaching above the helium photosphere. In addition, we argue that
the He I line-formation region is likely to have been in the form of pure
helium clumps in the hydrogen envelope.Comment: Accepted for publication in MNRAS, 32 pages including 11 figures
(uses psfig.sty - included
Relationship between the Romberg Test and the Wii Basic Balance Test and Cognition in Athletes with Concussion
Background: Approximately 30% of individuals with a sport-related concussion present with postural instability. Multiple clinical balance tests exist to diagnose postural instability; yet little is known about the potential relationship between these type of postural assessments and cognition post-concussion. Aim: The purpose of the current study was to assess the relationship between the Romberg test, the Wii Fit basic balance test (WBBT), and the composite scores on the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) test in a sample of athletes with concussions.
Methods: 55 post-concussed athletes (40 male) completed the Romberg Test (RT) (−/+), the WBBT, and ImPACT test. Wii Fit basic balance test performance was operationalized as the number of successfully completed trials (of 5 trials of increasing difficulty) within 30 seconds. Pearson’s and point-biserial correlations examined univariate associations among the variables.
Results: The RT and WBBT were not significantly related (r = −0.029, p = 0.832). The RT weakly correlated with ImPACT impairment scores (r= 0.26, p= 0.041), whereas WBBT the number of trials did not (r = − 0.20, p = 0.155). Romberg Test scores were significantly correlated with ImPACT Visual Processing Speed Score (r = 0.27, p = 0.036) and Reaction Time score (r = 0.34, p = 0.006). In contrast, WBBT trials were significantly correlated with the ImPACT Visual Memory Score (r = − 0.41, p = 0.003).
Conclusions: These results suggest that the WBBT and RT assess unique aspects of postural control. The RT may relate directly to single sensory cognitive and motor processing, while the WBBT may relate to multi-sensory visually driven cognitive and motor processing.
Relevance for patients: Clinical balance tests could point to different cognitive impairments post-concussion
Propuesta para implementar el programa de formación cívica y ética en primaria desde una estrategia enriquecida por la gestión directiva
Proyecto de intervención llevado a cabo en la escuela primaria federalizada Patria con el objetivo de generar estrategias para ayudar a los profesores en la formación valoral y cívica de los alumnos. Se propuso un taller para docentes para que conocieran y aplicaran de mejor forma el Programa de Formación Cívica (2009-2010) de la Secretaría de Educación Pública (SEP). Además, se diseñaron actividades transversales de formación en valores, las cuales fueron desarrolladas con los alumnos, profesores y con los padres de familia
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Population History and Gene Divergence in Native Mexicans Inferred from 76 Human Exomes.
Native American genetic variation remains underrepresented in most catalogs of human genome sequencing data. Previous genotyping efforts have revealed that Mexico's Indigenous population is highly differentiated and substructured, thus potentially harboring higher proportions of private genetic variants of functional and biomedical relevance. Here we have targeted the coding fraction of the genome and characterized its full site frequency spectrum by sequencing 76 exomes from five Indigenous populations across Mexico. Using diffusion approximations, we modeled the demographic history of Indigenous populations from Mexico with northern and southern ethnic groups splitting 7.2 KYA and subsequently diverging locally 6.5 and 5.7 KYA, respectively. Selection scans for positive selection revealed BCL2L13 and KBTBD8 genes as potential candidates for adaptive evolution in Rarámuris and Triquis, respectively. BCL2L13 is highly expressed in skeletal muscle and could be related to physical endurance, a well-known phenotype of the northern Mexico Rarámuri. The KBTBD8 gene has been associated with idiopathic short stature and we found it to be highly differentiated in Triqui, a southern Indigenous group from Oaxaca whose height is extremely low compared to other Native populations
Salivary Parameters (Salivary Flow, pH and Buffering Capacity) in Stimulated Saliva of Mexican Elders 60 Years Old and Older
Objective: To compare a limited array of chewing-stimulated saliva features (salivary flow, pH and
buffer capacity) in a sample of elderly Mexicans with clinical, sociodemographic and socio-economic
variables.
Subjects and Methods: A cross-sectional study was carried out in 139 adults, 60 years old and older,
from two retirement homes and a senior day care centre in the city of Pachuca, Mexico. Sociodemographic, socio-economic and behavioural variables were collected through a questionnaire. A
trained and standardized examiner obtained the oral clinical variables. Chewing-stimulated saliva
(paraffin method) was collected and the salivary flow rate, pH and buffer capacity were measured. The
analysis was performed using non-parametric tests in Stata 9.0.
Results: Mean age was 79.1 ± 9.8 years. Most of the subjects included were women (69.1%). Mean
chewing-stimulated salivary flow was 0.75 ± 0.80 mL/minute, and the pH and buffer capacity were 7.88
± 0.83 and 4.20 ± 1.24, respectively. Mean chewing-stimulated salivary flow varied (p < 0.05) across
type of retirement home, tooth brushing frequency, number of missing teeth and use of dental prostheses.
pH varied across the type of retirement home (p < 0.05) and marginally by age (p = 0.087); buffer
capacity (p < 0.05) varied across type of retirement home, tobacco consumption and the number of
missing teeth.
Conclusions: These exploratory data add to the body of knowledge with regard to chewing-stimulated
salivary features (salivary flow rate, pH and buffer capacity) and outline the variability of those features
across selected sociodemographic, socio-economic and behavioural variables in a group of Mexican
elders
Preparation, characterization, intrinsic dissolution studies and microbiological assessment of dapsone tosylate polymorphs
Purpose: To prepare dapsone tosylate salt (TD) and its two polymorphs (TD-I and TD-II), and study their intrinsic dissolution profiles and preliminary anti-mycobacterium activity.Methods: The synthesized product was studied with respect to the effect of solvent selection, reaction temperature and evaporation rate on the solid phase obtained. The polymorphs were characterized using powder x-ray diffraction (PXRD), proton nuclear magnetic resonance (1H-NMR), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). UV/Vis spectroscopy was employed for quantification of the salt, while Wood apparatus was used for dissolution studies. Microdilution assay, using a 96-well equipment, was employed for the evaluation of anti-mycobacterial activity.Results: On analysis of the solids obtained from synthesis with PXRD, two different patterns were observed. One pattern belonged to TD-I, previously reported, and the other was a new polymorph TD-II. Solvent evaporation was important in the selective preparation of TD-I or TD-II. Analyses with DSC, TGA and 1H-NMR revealed the absence of solvent in both solids and showed that TD-II was not a solvated salt. Spectral analysis with FT-IR demonstrated structural relationship between TD-I and TD-II. Intrinsic dissolution studies showed that both polymorphs dissolved faster than dapsone (DAP).Conclusion: It is possible to synthesize TD and select the polymorph prepared by means of modulated solvent evaporation rate. The rank order of the intrinsic dissolution rate constants was TD-II > TD-I > DAP. The tosylate salt enhanced inhibitory effect on M. fortuitum, when compared to DAP.Keywords: Dapsone tosylate, Polymorphism, Solid phase characteristics, Intrinsic dissolution, Antimycobacterium activit
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