4,282 research outputs found
Sector primario, sustentabilidad y turismo: el problema de valoración de los recursos naturales y culturales en turismo
Se plantean las dificultades que supone valorar los recursos naturales y culturales en el campo teórico-práctico del turismo, recurriendo a una conexión entre la categorÃa sector primario, la temática de la sustentabilidad, y la actividad turÃstica, con toda la complejidad que ello implica. Se propone que el valor de tales recursos se subestima si se equipara con el precio y que serÃa necesario incorporar un valor simbólico y un pago en grado de conciencia
Comunidades en la zona de influencia del Parque Izta-Popo: buscando una ruta hacia el turismo sustentable
Pulmonary thromboembolism and alveolar hemorrhage as initial manifestations of systemic lupus erythematosus
Systemic lupus erythematosus (SLE) is an autoimmune disease that affects multiple organs. SLE can affect the lung, the pulmonary vasculature, and the pleura. A 38-year-old female with limb pain and ecchymosis who later developed pulmonary thromboembolism and alveolar hemorrhage is presented here. Clinical, imaging, laboratory, and histopathological evidence is presented. The patient met the European League Against Rheumatism (EULAR) and the American College of Rheumatology (ACR) criteria for SLE. Furthermore, the patient had a Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) score of 35; thus, indicating severe disease. This case is an example of concomitant venous and arterial lung complications in an SLE patient
Two dimensional ferroelectric domain patterns in Yb3+ optically active LiNbO3 fabricated by direct electron beam writing
The following article appeared in Applied Physics Letters 102.4 (2013): 042910 and may be found at http://scitation.aip.org/content/aip/journal/apl/102/4/10.1063/1.4790149We report on highly controllable ferroelectric domain inversion in Yb 3+ doped LiNbO3 laser crystal. The ferroelectric domain patterns are fabricated by direct electron beam writing without any previous masking process. Square lattices of inverted domains with diameters and distance between domains as low as 1 μm are demonstrated. The lateral growth of the inverted domains is analyzed as a function of the applied charge and the threshold values for domains in the 1-10 μm length scale are determined. Spatially resolved low temperature fluorescence spectroscopy and non-collinear second harmonic generation experiments are also employed to evaluate the optical properties of the system.This work has been supported by Spanish Government under Project No. MAT2010-17443 and Comunidad de Madrid under Grant No. S2009/1756
Multiple mitochondrial introgression events and heteroplasmy in trypanosoma cruzi revealed by Maxicircle MLST and next generation sequencing
Background
Mitochondrial DNA is a valuable taxonomic marker due to its relatively fast rate of evolution. In Trypanosoma cruzi, the causative agent of Chagas disease, the mitochondrial genome has a unique structural organization consisting of 20–50 maxicircles (∼20 kb) and thousands of minicircles (0.5–10 kb). T. cruzi is an early diverging protist displaying remarkable genetic heterogeneity and is recognized as a complex of six discrete typing units (DTUs). The majority of infected humans are asymptomatic for life while 30–35% develop potentially fatal cardiac and/or digestive syndromes. However, the relationship between specific clinical outcomes and T. cruzi genotype remains elusive. The availability of whole genome sequences has driven advances in high resolution genotyping techniques and re-invigorated interest in exploring the diversity present within the various DTUs.
Methodology/Principal Findings
To describe intra-DTU diversity, we developed a highly resolutive maxicircle multilocus sequence typing (mtMLST) scheme based on ten gene fragments. A panel of 32 TcI isolates was genotyped using the mtMLST scheme, GPI, mini-exon and 25 microsatellite loci. Comparison of nuclear and mitochondrial data revealed clearly incongruent phylogenetic histories among different geographical populations as well as major DTUs. In parallel, we exploited read depth data, generated by Illumina sequencing of the maxicircle genome from the TcI reference strain Sylvio X10/1, to provide the first evidence of mitochondrial heteroplasmy (heterogeneous mitochondrial genomes in an individual cell) in T. cruzi.
Conclusions/Significance
mtMLST provides a powerful approach to genotyping at the sub-DTU level. This strategy will facilitate attempts to resolve phenotypic variation in T. cruzi and to address epidemiologically important hypotheses in conjunction with intensive spatio-temporal sampling. The observations of both general and specific incidences of nuclear-mitochondrial phylogenetic incongruence indicate that genetic recombination is geographically widespread and continues to influence the natural population structure of TcI, a conclusion which challenges the traditional paradigm of clonality in T. cruzi
Noncommutative 6D Gauge Higgs Unification Models
The influence of higher dimensions in noncommutative field theories is
considered. For this purpose, we analyze the bosonic sector of a recently
proposed 6 dimensional SU(3) orbifold model for the electroweak interactions.
The corresponding noncommutative theory is constructed by means of the
Seiberg-Witten map in 6D. We find in the reduced bosonic interactions in 4D
theory, couplings which are new with respect to other known 4D noncommutative
formulations of the Standard Model using the Seiberg-Witten map.
Phenomenological implications due to the noncommutativity of extra dimensions
are explored. In particular, assuming that the commutative model leads to the
standard model values, a bound -5.63 10^{-8} GeV^{-2}< theta <1.06
10^{-7}GeV^{-2} on the corresponding noncommutativity scale is derived from
current experimental constraints on the S and T oblique parameters. This bound
is used to predict a possibly significant impact of noncommutativity effects of
extra dimensions on the rare Higgs boson decay H-> gamma gamma.Comment: Latex file, 11 pages, 1 figur
Análisis de la relevancia de las revistas latinoamericanas a través de un factor de impacto renormalizado
In this work we use a renormalized impact factor to analyze the time evolution of Latin American scientific journals from 1991 to 2000. Our analysis shows oscillant behavior in journals’ relevance in the international context in the last years.<br><br>En este trabajo usamos el factor de impacto renormalizado para obtener la evolución temporal de un indicador de relevancia de las revistas cientÃficas latinoamericanas en el periodo de 1991 a 2000. Nuestro análisis muestra un comportamiento oscilante en la relevancia en el contexto internacional en los últimos años
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