2,873 research outputs found
Recovery of wheat heritage for traditional food: genetic variation for high molecular weight glutenin subunits in neglected/underutilized wheat
Club wheat (Triticum aestivum L. ssp. compactum (Host) Mackey), macha wheat (T. aestivum L. ssp. macha (Dekapr. & A.M. Menabde) Mackey) and Indian dwarf wheat (T. aestivum L. ssp. sphaerococcum (Percival) Mackey) are three neglected or underutilized subspecies of hexaploid wheat. These materials were and are used to elaborate modern and traditional products, and they could be useful in the revival of traditional foods. Gluten proteins are the main grain components defining end-use quality. The high molecular weight glutenin subunit compositions of 55 accessions of club wheat, 29 accessions of macha wheat, and 26 accessions of Indian dwarf wheat were analyzed using SDS-PAGE. Three alleles for the Glu-A1 locus, 15 for Glu-B1 (four not previously described), and four for Glu-D1 were detected. Their polymorphisms could be a source of genes for quality improvement in common wheat, which would permit both their recovery as new crops and development of modern cultivars with similar quality characteristics but better agronomic traits
Excited electronic states from a variational approach based on symmetry-projected Hartree--Fock configurations
Recent work from our research group has demonstrated that symmetry-projected
Hartree--Fock (HF) methods provide a compact representation of molecular ground
state wavefunctions based on a superposition of non-orthogonal Slater
determinants. The symmetry-projected ansatz can account for static correlations
in a computationally efficient way. Here we present a variational extension of
this methodology applicable to excited states of the same symmetry as the
ground state. Benchmark calculations on the C dimer with a modest basis
set, which allows comparison with full configuration interaction results,
indicate that this extension provides a high quality description of the
low-lying spectrum for the entire dissociation profile. We apply the same
methodology to obtain the full low-lying vertical excitation spectrum of
formaldehyde, in good agreement with available theoretical and experimental
data, as well as to a challenging model insertion pathway for BeH.
The variational excited state methodology developed in this work has two
remarkable traits: it is fully black-box and will be applicable to fairly large
systems thanks to its mean-field computational cost
Objeto virtual de aprendizaje para la concientización frente a los fenómenos naturales o antrópicos que se suscitan en el departamento de Nariño
La prevención y atención de desastres es una temática de interés general. En el caso particular del departamento de Nariño son diversas las amenazas a las cuales se encuentra expuesto cada uno de los municipios que lo conforman; por ello, es de gran importancia la implementación de nuevos elementos que contribuyan al conocimiento de los fenómenos que causan estas amenazas, para así contribuir en la gestión del riesgo en toda la comunidad, principalmente en la que se encuentra más vulnerable
On the Nature of the Strong Emission-Line Galaxies in Cluster Cl 0024+1654: Are Some the Progenitors of Low Mass Spheroidals?
We present new size, line ratio, and velocity width measurements for six
strong emission-line galaxies in the galaxy cluster, Cl 0024+1654, at redshift
z~0.4. The velocity widths from Keck spectra are all narrow (30<sigma<120
km/s), with three profiles showing double peaks. Four galaxies have low masses
(M<10^{10} Mo). Whereas three galaxies were previously reported to be possible
AGNs, none exhibit AGN-like emission line ratios or velocity widths. Two or
three appear as very blue spirals with the remainder more akin to luminous H-II
galaxies undergoing a strong burst of star formation. We propose that after the
burst subsides, these galaxies will transform into quiescent dwarfs, and are
thus progenitors of some cluster spheroidals (We adopt the nomenclature
suggested by Kormendy & Bender (1994), i.e., low-density, dwarf ellipsoidal
galaxies like NGC 205 are called `spheroidals' instead of `dwarf ellipticals')
seen today.Comment: 14 pages + 2 figures + 1 table, LaTeX, Acc. for publ. in ApJL also
available at http://www.ucolick.org/~deep/papers/papers.htm
Cáncer gástrico
ResumenEl cáncer gástrico (CG) mantiene alta prevalencia en Chile, con una tasa de mortalidad de 20/100.000 habitantes. Se reconocen dos variantes histológicas, el tipo difuso y el tipo intestinal. El primero crece en forma de células sueltas y el segundo forma glándulas semejantes a las intestinales. Para el intestinal, la histogénesis se inicia con una gastritis atrófica, seguida de metaplasia, displasia y cáncer a diferencia del difuso cuya histogénesis es diferente, en mucosa fúndica. Ambos pueden presentarse combinados, en ambos se reconoce asociación con el Helicobacter Pylori y otros factores ambientales, pero el de tipo intestinal es el más caracteristico de áreas de alta incidencia y el difuso tiene una vertiente más asociada a factores hereditarios. Además, entre ambos existen diferencias de comportamiento clinico. La clasificación de origen japonés en cáncer incipiente y avanzado mantiene utilidad por su trascendencia pronóstica y terapéutica. Para la etapificación clinica (c) y patológica (p)se ha universalizado el sistema TNM. Los sintomas son inespecificos y sugieren una enfermedad avanzada. Esto justifica politicas de prevención, el reconocimiento de factores de riesgo y la endoscopía con biopsia aun ante síntomas sutiles. La etapificación clínica y el tratamiento se definen en comité multidisciplinario. La tomografía de tórax, abdomen y pelvis es el examen inicial y se complementa según necesidad y disponibilidad. Para el tratamiento no existe un procedimiento estándar Para tumores T1a se considera la resección endoscópica y para los avanzados, la resección quirúrgica tipo D2- RO. Esta puede hacerse por vía abierta o laparoscópica. Para tumores avanzados o con compromiso ganglionar se indica neoadyuvancia o adyuvancia. En algunos pacientes el tratamiento solo tiene objetivos paliativos.SummaryGastric Cancer (GC) is highly prevalent in Chile, with a mortality rate of 20/100.000 inhabitants. Two histological entities are recognized: diffuse type (isolated tumoral cells) and intestinal type (intestinal-like glandular structures). For the latter the sequence of atrophy, metaplasia, displasia and progression to cancer is recognized whereas the diffuse type grows mainly in fundic mucosa. Both may present combined, and both have carcinogenetic association with Helicobacter Pylori. The intestinal type is characteristic for high risk areas whereas the diffuse type has been associated more frequently with genetic-hereditary predisposition. The Japanese classification of early and advanced GC mantains therapeutic and prognostic value. For clinical (c) and patological (p) staging the TNM system is of generalized use. Symptoms are non specific, and suggest an advanced disease. Therefore strategies for prevention in high risk areas must be designed. Clinical awareness, the recognition of risk factors, and early endoscopy with biopsy may be helpful for an early diagnosis. Individual staging and treatment are mutidisciplinary. Computed tomography of the chest, abdomen and pelvis is complemented by other studies according to individual indication. Treatment should be individually tailored. For Tla tumors endoscopic treatment is available with excellent results but with follow-up commitment. For advanced localized tumors D2-R0 resection is indicated. Neo adyuvant or adyuvant treatment should be considered in these patients. Some patients with diseminated disease only allow palliative treatment
Casimir torque
We develop a formalism for the calculation of the flow of angular momentum
carried by the fluctuating electromagnetic field within a cavity bounded by two
flat anisotropic materials. By generalizing a procedure employed recently for
the calculation of the Casimir force between arbitrary materials, we obtain an
expression for the torque between anisotropic plates in terms of their
reflection amplitude matrices. We evaluate the torque in 1D for ideal and
realistic model materials.Comment: 8 pages, 4 figs, Submitted to Proc. of QFEXT'05, to appear in J.
Phys.
Shilajit: A Natural Phytocomplex with Potential Procognitive Activity
Shilajit is a natural substance found mainly in the Himalayas, formed for centuries by the gradual decomposition of certain plants by the action of microorganisms. It is a potent and very safe dietary supplement, restoring the energetic balance and potentially able to prevent several diseases. Recent investigations point to an interesting medical application toward the control of cognitive disorders associated with aging, and cognitive stimulation. Thus, fulvic acid, the main active principle, blocks tau self-aggregation, opening an avenue toward the study of Alzheimer's therapy. In essence, this is a nutraceutical product of demonstrated benefits for human health. Considering the expected impact of shilajit usage in the medical field, especially in the neurological sciences, more investigations at the basic biological level as well as clinical trials are necessary, in order to understand how organic molecules of shilajit and particularly fulvic acid, one of the active principles, and oligoelements act at both the molecular and cellular levels and in the whole organism
Social media brand engagement in the context of collaborative consumption: the case of AIRBNB
This study focuses on social media brand engagement in the context of shared and collaborative consumption businesses, a novel trend in the hospitality industry. By drawing on the concept of brands being defined collectively through an assemblage of heterogonous human and nonhuman actors, and focusing on the brand Airbnb—a peer-to-peer online platform for renting, swapping, and lending accommodations—the current study examines how consumers’ perceptions of Airbnb brand equity mediate the relationship between functional and hedonic brand image and social media behavioral engagement in terms of consumption, contribution, and creation of brand-related content (COBRAs). Results discriminate between direct and indirect effects. Findings reveal that hedonic brand image directly influences behavioral engagement on social media, whereas brand equity fully mediates the relationship between functional brand image and COBRAs. Implications for theory and practice related to shared or collaborative consumption platforms in the hospitality industry are discussed and suggestions for future studies are presented. This research paper provides conceptual and theoretical clarity on issues such as how consumers’ brand perceptions influence their behavioral engagement on social media.info:eu-repo/semantics/acceptedVersio
Variable number of tandem repeat markers in the genome sequence of Mycosphaerella fijiensis, the causal agent of black leaf streak disease of banana (Musa spp)
ABSTRACT. We searched the genome of Mycosphaerella fijiensis for molecular markers that would allow population genetics analysis of this plant pathogen. M. fijiensis, the causal agent of banana leaf streak disease, also known as black Sigatoka, is the most devastating pathogen attacking bananas (Musa spp). Recently, the entire genome sequence of M. fijiensis became available. We screened this database for VNTR markers. Forty-two primer pairs were selected for validation, based on repeat type and length and the number of repeat units. Five VNTR markers showing multiple alleles were validated with a reference set of isolates from different parts of the world and a population from a banana plantation in Costa Rica. Polymorphism information content values varied from 0.6414 to 0.7544 for the reference set and from 0.0400 and 0.7373 for the population set. Eighty percent of the polymorphism information content values were above 0.60, indicating that the markers are highly informative. These markers allowed robust scoring of agarose gels and proved to be useful for variability and population genetics studies. In conclusion, the strategy we developed to identify and validate VNTR markers is an efficient means to incorporate markers that can be used for fungicide resistance management and to develop breeding strategies to control banana black leaf streak disease. This is the first report of VNTR-minisatellites from the M. fijiensis genome sequence. Key words: Molecular markers; VNTRs; Genetic diversity; Population genetics; Black Sigatok
- …