48 research outputs found
Nearest-Neighbor Distributions and Tunneling Splittings in Interacting Many-Body Two-Level Boson Systems
We study the nearest-neighbor distributions of the -body embedded
ensembles of random matrices for bosons distributed over two-degenerate
single-particle states. This ensemble, as a function of , displays a
transition from harmonic oscillator behavior () to random matrix type
behavior (). We show that a large and robust quasi-degeneracy is present
for a wide interval of values of when the ensemble is time-reversal
invariant. These quasi-degenerate levels are Shnirelman doublets which appear
due to the integrability and time-reversal invariance of the underlying
classical systems. We present results related to the frequency in the spectrum
of these degenerate levels in terms of , and discuss the statistical
properties of the splittings of these doublets.Comment: 13 pages (double column), 7 figures some in color. The movies can be
obtained at http://link.aps.org/supplemental/10.1103/PhysRevE.81.03621
Fidelity decay in interacting two-level boson systems: Freezing and revivals
We study the fidelity decay in the -body embedded ensembles of random
matrices for bosons distributed in two single-particle states, considering the
reference or unperturbed Hamiltonian as the one-body terms and the diagonal
part of the -body embedded ensemble of random matrices, and the perturbation
as the residual off-diagonal part of the interaction. We calculate the
ensemble-averaged fidelity with respect to an initial random state within
linear response theory to second order on the perturbation strength, and
demonstrate that it displays the freeze of the fidelity. During the freeze, the
average fidelity exhibits periodic revivals at integer values of the Heisenberg
time . By selecting specific -body terms of the residual interaction,
we find that the periodicity of the revivals during the freeze of fidelity is
an integer fraction of , thus relating the period of the revivals with the
range of the interaction of the perturbing terms. Numerical calculations
confirm the analytical results
Association between the histopathologic findings of a zero-time biopsy and the donor kidney function 24 hours and a year after nephrectomy
Background: The living-donor transplantation (LDT) is essential to provide patients with chronic kidney disease (CKD) a superior quality of life and improve their lifespan. Recent investigations prove that the living donors (LD) have a risk of developing CKD, without there being a way to anticipate it. The zero-time biopsies provide valuable information that may contribute to this objective since they report histopathologic findings of subclinical chronic damage. Methods: Retrospective, observational and analytical study. The information from the medical files and pathology department of LD attended at “Dr. Miguel Silva” general hospital from January 2006 to January 2018 was analyzed. The glomerular filtrate rate was obtained 24 hours and a year after nephrectomy and was estimated based on CDK-EPI. The comparison among groups was made through Mann-Whitney testing for continuous numeric. A value of p36 years, the dropping of the GFR >43%, the GFR and the creatinine levels after 24 hours of nephrectomy were associated with a reduction of the GFR the year after nephrectomy
Brechas de rendimiento de girasol en Argentina
Achicar las brechas en Girasol hasta lograr el 80% del rendimiento potencial en secano implicaría un ingreso adicional estimado para el país de 250 millones de dólares anuales.EEA BalcarceFil: Rodríguez, I.M. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Troglia, Carolina Beatriz. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Zuil, Sebastián. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina.Fil: Quiroz, Facundo José. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Aramburu Merlos, Facundo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Cipriotti, Pablo. Universidad de Buenos Aires. Facultad de Agronomía; Argentina.Fil: Hall, Antonio Juan. Universidad de Buenos Aires. Facultad de Agronomía; Argentina.Fil: Mercau, Jorge Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Luis; Argentina.Fil: Monzón, Juan Pablo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina
Genetic Footprints of Iberian Cattle in America 500 Years after the Arrival of Columbus
Background: American Creole cattle presumably descend from animals imported from the Iberian Peninsula during the period of
colonization and settlement, through different migration routes, andmay have also suffered the influence of cattle directly imported
from Africa. The introduction of European cattle, which began in the 18th century, and later of Zebu from India, has threatened the
survival of Creole populations, some of which have nearly disappeared or were admixed with exotic breeds. Assessment of the
genetic status of Creole cattle is essential for the establishment of conservation programs of these historical resources.
Methodology/Principal Findings: We sampled 27 Creole populations, 39 Iberian, 9 European and 6 Zebu breeds. We used
microsatellite markers to assess the origins of Creole cattle, and to investigate the influence of different breeds on their
genetic make-up. The major ancestral contributions are from breeds of southern Spain and Portugal, in agreement with the
historical ports of departure of ships sailing towards the Western Hemisphere. This Iberian contribution to Creoles may also
include some African influence, given the influential role that African cattle have had in the development of Iberian breeds,
but the possibility of a direct influence on Creoles of African cattle imported to America can not be discarded. In addition to
the Iberian influence, the admixture with other European breeds was minor. The Creoles from tropical areas, especially
those from the Caribbean, show clear signs of admixture with Zebu.
Conclusions/Significance: Nearly five centuries since cattle were first brought to the Americas, Creoles still show a strong
and predominant signature of their Iberian ancestors. Creole breeds differ widely from each other, both in genetic structure
and influences from other breeds. Efforts are needed to avoid their extinction or further genetic erosion, which would
compromise centuries of selective adaptation to a wide range of environmental condition
The genetic ancestry of American Creole cattle inferred from uniparental and autosomal genetic markers
Cattle imported from the Iberian Peninsula spread throughout America in the early years of discovery and colonization to originate Creole breeds, which adapted to a wide diversity of environments and later received influences from other origins, including zebu cattle in more recent years. We analyzed uniparental genetic markers and autosomal microsatellites in DNA samples from 114 cattle breeds distributed worldwide, including 40 Creole breeds representing the whole American continent, and samples from the Iberian Peninsula, British islands, Continental Europe, Africa and American zebu. We show that Creole breeds differ considerably from each other, and most have their own identity or group with others from neighboring regions. Results with mtDNA indicate that T1c-lineages are rare in Iberia but common in Africa and are well represented in Creoles from Brazil and Colombia, lending support to a direct African influence on Creoles. This is reinforced by the sharing of a unique Y-haplotype between cattle from Mozambique and Creoles from Argentina. Autosomal microsatellites indicate that Creoles occupy an intermediate position between African and European breeds, and some Creoles show a clear Iberian signature. Our results confirm the mixed ancestry of American Creole cattle and the role that African cattle have played in their development
Addressing the disparities in dementia risk, early detection and care in Latino populations: Highlights from the Second Latinos and Alzheimer's Symposium
The Alzheimer's Association hosted the second Latinos & Alzheimer's Symposium in May 2021. Due to the COVID-19 pandemic, the meeting was held online over 2 days, with virtual presentations, discussions, mentoring sessions, and posters. The Latino population in the United States is projected to have the steepest increase in Alzheimer's disease (AD) in the next 40 years, compared to other ethnic groups. Latinos have increased risk for AD and other dementias, limited access to quality care, and are severely underrepresented in AD and dementia research and clinical trials. The symposium highlighted developments in AD research with Latino populations, including advances in AD biomarkers, and novel cognitive assessments for Spanish-speaking populations, as well as the need to effectively recruit and retain Latinos in clinical research, and how best to deliver health-care services and to aid caregivers of Latinos living with AD
Clinical Presentation and Outcomes of Kawasaki Disease in Children from Latin America: A Multicenter Observational Study from the REKAMLATINA Network
Objetivos: Describir la presentación clínica, el manejo y los resultados de la enfermedad de Kawasaki (EK) en Latinoamérica y evaluar los indicadores pronósticos tempranos de aneurisma de la arteria coronaria (AAC). Diseño del estudio: Se realizó un estudio observacional basado en el registro de la EK en 64 centros pediátricos participantes de 19 países latinoamericanos de forma retrospectiva entre el 1 de enero de 2009 y el 31 de diciembre de 2013, y de forma prospectiva desde el 1 de junio de 2014 hasta el 31 de mayo de 2017. Se recopilaron datos demográficos, clínicos y de laboratorio iniciales. Se utilizó una regresión logística que incorporaba factores clínicos y la puntuación z máxima de la arteria coronaria en la presentación inicial (entre 10 días antes y 5 días después de la inmunoglobulina intravenosa [IGIV]) para desarrollar un modelo pronóstico de AAC durante el seguimiento (>5 días después de la IGIV). Resultados: De 1853 pacientes con EK, el ingreso tardío (>10 días tras el inicio de la fiebre) se produjo en el 16%, el 25% tuvo EK incompleta y el 11% fue resistente a la IGIV. Entre los 671 sujetos con puntuación z de la arteria coronaria notificada durante el seguimiento (mediana: 79 días; IQR: 36, 186), el 21% presentaba AAC, incluido un 4% con aneurismas gigantes. Un modelo pronóstico simple que utilizaba sólo una puntuación z de la arteria coronaria máxima ≥2,5 en la presentación inicial fue óptimo para predecir la AAC durante el seguimiento (área bajo la curva: 0,84; IC del 95%: 0,80, 0,88). Conclusiones: De nuestra población latinoamericana, la puntuación z de la arteria coronaria ≥2,5 en la presentación inicial fue el factor pronóstico más importante que precedió a la AAC durante el seguimiento. Estos resultados resaltan la importancia de la ecocardiografía temprana durante la presentación inicial de la EK. © 2023 Los autoresObjectives: To describe the clinical presentation, management, and outcomes of Kawasaki disease (KD) in Latin America and to evaluate early prognostic indicators of coronary artery aneurysm (CAA). Study design: An observational KD registry-based study was conducted in 64 participating pediatric centers across 19 Latin American countries retrospectively between January 1, 2009, and December 31, 2013, and prospectively from June 1, 2014, to May 31, 2017. Demographic and initial clinical and laboratory data were collected. Logistic regression incorporating clinical factors and maximum coronary artery z-score at initial presentation (between 10 days before and 5 days after intravenous immunoglobulin [IVIG]) was used to develop a prognostic model for CAA during follow-up (>5 days after IVIG). Results: Of 1853 patients with KD, delayed admission (>10 days after fever onset) occurred in 16%, 25% had incomplete KD, and 11% were resistant to IVIG. Among 671 subjects with reported coronary artery z-score during follow-up (median: 79 days; IQR: 36, 186), 21% had CAA, including 4% with giant aneurysms. A simple prognostic model utilizing only a maximum coronary artery z-score ≥2.5 at initial presentation was optimal to predict CAA during follow-up (area under the curve: 0.84; 95% CI: 0.80, 0.88). Conclusion: From our Latin American population, coronary artery z-score ≥2.5 at initial presentation was the most important prognostic factor preceding CAA during follow-up. These results highlight the importance of early echocardiography during the initial presentation of KD. © 2023 The Author(s
Sustentabilidad y tecnología. Herramientas para la gestión segura y eficiente del hábitat
Por décadas permeó una visión de la tecnología como una de las principales fuentes del ataque al medio ambiente y de su degradación. Hoy se le considera como un aliado para combatir los efectos negativos de la perenne negligencia ecológica humana.
El uso de la tecnología para la implementación de estrategias innovadoras y eficaces en favor del medio ambiente, un hábitat seguro y sustentable, se abordó en el Congreso Internacional sobre Sustentabilidad en los Hábitats, realizado en 2016. De este encuentro entre estudiantes, especialistas, autoridades y organizaciones civiles de América Latina, Asia y Europa emana este libro, que incluye dos ejes de relevancia global: los retos en el manejo sustentable de los recursos naturales y el uso de tecnologías para la edificación sustentable. En el primero se atienden desde los riesgos asociados al crecimiento demográfico desproporcionado hasta acciones de carácter remedial para la contaminación; mientras que en el segundo se aborda el desarrollo de tecnología e infraestructura para mejorar el hábitat urbano, así como procesos donde alumnos y profesores confeccionan soluciones para la sustentabilidad energética.
En su conjunto, es una obra de consulta que busca ser un detonador para generar nuevas líneas de trabajo, repensar las soluciones y dialogar con lectores interesados en la construcción de un mundo mejor.Consejo Estatal de Ciencia y Tecnología de Jalisc
The genetic ancestry of american creole cattle inferred from uniparental and autosomal genetic markers.
Cattle imported from the Iberian Peninsula spread throughout America in the early years of discovery and colonization to originate Creole breeds, which adapted to a wide diversity of environments and later received influences from other origins, including zebu cattle in more recent years. We analyzed uniparental genetic markers and autosomal microsatellites in DNA samples from 114 cattle breeds distributed worldwide, including 40 Creole breeds representing the whole American continent, and samples from the Iberian Peninsula, British islands, Continental Europe, Africa and American zebu. We show that Creole breeds differ considerably from each other, and most have their own identity or group with others from neighboring regions. Results with mtDNA indicate that T1c-lineages are rare in Iberia but common in Africa and are well represented in Creoles from Brazil and Colombia, lending support to a direct African influence on Creoles. This is reinforced by the sharing of a unique Y-haplotype between cattle from Mozambique and Creoles from Argentina. Autosomal microsatellites indicate that Creoles occupy an intermediate position between African and European breeds, and some Creoles show a clear Iberian signature. Our results confirm the mixed ancestry of American Creole cattle and the role that African cattle have played in their development