485 research outputs found
On axiomatic definitions of non-discrete affine buildings
In this paper we prove equivalence of sets of axioms for non-discrete affine
buildings, by providing different types of metric, exchange and atlas
conditions. We apply our result to show that the definition of a Euclidean
building depends only on the topological equivalence class of the metric on the
model space. The sharpness of the axioms dealing with metric conditions is
illustrated in an appendix. There it is shown that a space X defined over a
model space with metric d is possibly a building only if the induced distance
function on X satisfies the triangle inequality.Comment: Errors corrected, results extended. (This replaces the two earlier,
separate preprints "Axioms of affine buidlings" arXiv:0909.2967v1 and "Affine
buildings II" arXiv:0909.2059v1.
Observations from Preliminary Experiments on Spatial and Temporal Pressure Measurements from Near-Field Free Air Explosions
It is self-evident that a crucial step in analysing the performance of protective structures is to be able to accurately quantify the blast load arising from a high explosive detonation. For structures located near to the source of a high explosive detonation, the resulting pressure is extremely high in magnitude and highly non-uniform over the face of the target. There exists very little direct measurement of blast parameters in the nearfield, mainly attributed to the lack of instrumentation sufficiently robust to survive extreme loading events yet sensitive enough to capture salient features of the blast. Instead literature guidance is informed largely by early numerical analyses and parametric studies. Furthermore, the lack of an accurate, reliable data set has prevented subsequent numerical analyses from being validated against experimental trials. This paper presents an experimental methodology that has been developed in part to enable such experimental data to be gathered. The experimental apparatus comprises an array of Hopkinson pressure bars, fitted through holes in a target, with the loaded faces of the bars flush with the target face. Thus, the bars are exposed to the normally or obliquely reflected shocks from the impingement of the blast wave with the target. Pressure-time recordings are presented along with associated Arbitary-Langrangian-Eulerian modelling using the LS-DYNA explicit numerical code. Experimental results are corrected for the effects of dispersion of the propagating waves in the pressure bars, enabling accurate characterisation of the peak pressures and impulses from these loadings. The combined results are used to make comments on the mechanism of the pressure load for very near-field blast events
ZERO NET ENERGY TEST HOUSE
This paper describes the first phase of a residential research program to reduce the impact of new construction on the environment through research and education using a Zero Net Energy Test House as a framework. Containing four bedrooms, three and a half baths, the 1,800 square foot house, 1,000 square foot basement, is located in Omaha, Nebraska. It is being used to validate several research projects and provides a platform for applications research of a number of technological advances. Laminated photovoltaic solar panels, a wind turbine, and an occupant monitoring energy control system are some of the sustainable design innovations incorporated. Sustainable features are described that detail the application for LEED Platinum certification. Integrated into several University of Nebraska courses, the house has reached more than 200 students in the past year. Interdisciplinary teaching has involved design, construction, research, monitoring and energy analysis. Education opportunities have reached K–12 students, industry professionals, and public through tours and presentations
Charge Imbalance Effects on Interlayer Hopping and Fermi Surfaces in Multilayered High-T_c Cuprates
We study doping dependence of interlayer hoppings, t_\perp, in multilayered
cuprates with four or more CuO_2 planes in a unit cell. When the double
occupancy is forbidden in the plane, an effective amplitude of t_\perp in the
Gutzwiller approximation is shown to be proportional to the square root of the
product of doping rates in adjacent two planes, i.e., t^eff_\perp \propto
t_\perp \sqrt{\delta_1\delta_2}, where \delta_1 and \delta_2 represent the
doping rates of the two planes. More than three-layered cuprates have two kinds
of \cuo planes, i.e., inner- and outer planes (IP and OP), resulting in two
different values of t^eff_{\perp}, i.e., t^eff_\perp 1 \propto t_\perp
\sqrt{\delta_IP \delta_IP} between IP's, and t^eff_\perp 2 \propto t_\perp
\sqrt{\delta_IP \delta_OP} between IP and OP. Fermi surfaces are calculated in
the four-layered t-t'-t''-J model by the mean-field theory. The order
parameters, the renormalization factor of t_\perp, and the site-potential
making the charge imbalance between IP and OP are self-consistently determined
for several doping rates. We show the interlayer splitting of the Fermi
surfaces, which may be observed in the angle resolved photoemission
spectroscopy measurement.Comment: Some typographical errors are revised. Journal of Physical Society of
Japan, Vol.75, No.3, in pres
Genome-Wide Profiling of H3K56 Acetylation and Transcription Factor Binding Sites in Human Adipocytes
The growing epidemic of obesity and metabolic diseases calls for a better understanding of adipocyte biology. The regulation of transcription in adipocytes is particularly important, as it is a target for several therapeutic approaches. Transcriptional outcomes are influenced by both histone modifications and transcription factor binding. Although the epigenetic states and binding sites of several important transcription factors have been profiled in the mouse 3T3-L1 cell line, such data are lacking in human adipocytes. In this study, we identified H3K56 acetylation sites in human adipocytes derived from mesenchymal stem cells. H3K56 is acetylated by CBP and p300, and deacetylated by SIRT1, all are proteins with important roles in diabetes and insulin signaling. We found that while almost half of the genome shows signs of H3K56 acetylation, the highest level of H3K56 acetylation is associated with transcription factors and proteins in the adipokine signaling and Type II Diabetes pathways. In order to discover the transcription factors that recruit acetyltransferases and deacetylases to sites of H3K56 acetylation, we analyzed DNA sequences near H3K56 acetylated regions and found that the E2F recognition sequence was enriched. Using chromatin immunoprecipitation followed by high-throughput sequencing, we confirmed that genes bound by E2F4, as well as those by HSF-1 and C/EBPα, have higher than expected levels of H3K56 acetylation, and that the transcription factor binding sites and acetylation sites are often adjacent but rarely overlap. We also discovered a significant difference between bound targets of C/EBPα in 3T3-L1 and human adipocytes, highlighting the need to construct species-specific epigenetic and transcription factor binding site maps. This is the first genome-wide profile of H3K56 acetylation, E2F4, C/EBPα and HSF-1 binding in human adipocytes, and will serve as an important resource for better understanding adipocyte transcriptional regulation.Singapore. Agency for Science, Technology and Research (National Science Scholarship )Massachusetts Institute of Technology (Eugene Bell Career Development Chair)National Science Foundation (U.S.) (Award No. DBI-0821391)Pfizer Inc
A rough set-based association rule approach implemented on exploring beverages product spectrum
[[abstract]]When items are classified according to whether they have more or less of a characteristic, the scale used is referred to as an ordinal scale. The main characteristic of the ordinal scale is that the categories have a logical or ordered relationship to each other. Thus, the ordinal scale data processing is very common in marketing, satisfaction and attitudinal research. This study proposes a new data mining method, using a rough set-based association rule, to analyze ordinal scale data, which has the ability to handle uncertainty in the data classification/sorting process. The induction of rough-set rules is presented as method of dealing with data uncertainty, while creating predictive if—then rules that generalize data values, for the beverage market in Taiwan. Empirical evaluation reveals that the proposed Rough Set Associational Rule (RSAR), combined with rough set theory, is superior to existing methods of data classification and can more effectively address the problems associated with ordinal scale data, for exploration of a beverage product spectrum.[[notice]]補正完畢[[incitationindex]]SCI[[booktype]]紙本[[booktype]]電子
La computadora en la enseñanza de un primer curso de álgebra lineal en una Facultad de Ingeniería Química
El propósito de este trabajo es analizar esas cuestiones en el caso de la materia Matemática Básica, dictada en la Facultad de Ingeniería Química (FIQ) de la Universidad Nacional del Litoral (UNL) durante el primer semestre de 1998. Se considera ésta una ocasión especialmente faYorable, ya que recientes reformas realizadas por la UNL han establecido solo dos modalidades para el primer curso de matemática de todas las carreras de esta universidad. En el caso de la FIQ, esto significó el dictado de una asignatura conjunta para los alumnos ingresantes de las seis carreras que se cursan: Ingeniería en Alimentos (IA), Ingeniería Industrial(II), Ingeniería Química (IQ), Licenciatura en Matemática (LMA). Licenciatura en Química (LQ) y Técnico universitario Asistente Gerencial (TUAG). El equipo docente de esta asignatura estuvo integrado por los autores de este trabajo, a cargo de las clases teórico-prácticas y supervisión de las clases de laboratorio, y por los auxiliares de docencia: Jorge D'Elía, Adriana Frausin, Egle Haye, Ana Kanaslúro y Mlarcela Porta; encargados de las prácticas en computadora. El trabajo presenta en el punto 2 una descripción somera del curso. En el ítem 3 se analizan encuestas que recogen la opinión de estudiantes y docentes. como también las principales estadísticas de aprobación del primer cuatrimestre de 1998. En el punto 4 se exponen las conclusiones obtenidas. Finalmente, tres apéndices ilustran el desarrollo del trabajo, incluyendo: una guía de trabajos prácticos y un modelo de informe. en el Apéndice A: resúmenes de las encuestas realizadas, en el Apéndice B y ejemplos de ejercicios que se realizan usando el MATLAB, en el Apéndice C
Sirtuin 3, a New Target of PGC-1α, Plays an Important Role in the Suppression of ROS and Mitochondrial Biogenesis
Sirtuin 3 (SIRT3) is one of the seven mammalian sirtuins, which are homologs of the yeast Sir2 gene. SIRT3 is the only sirtuin with a reported association with the human life span. Peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha) plays important roles in adaptive thermogenesis, gluconeogenesis, mitochondrial biogenesis and respiration. PGC-1alpha induces several key reactive oxygen species (ROS)-detoxifying enzymes, but the molecular mechanism underlying this is not well understood.Here we show that PGC-1alpha strongly stimulated mouse Sirt3 gene expression in muscle cells and hepatocytes. Knockdown of PGC-1alpha led to decreased Sirt3 gene expression. PGC-1alpha activated the mouse SIRT3 promoter, which was mediated by an estrogen-related receptor (ERR) binding element (ERRE) (-407/-399) mapped to the promoter region. Chromatin immunoprecipitation and electrophoretic mobility shift assays confirmed that ERRalpha bound to the identified ERRE and PGC-1alpha co-localized with ERRalpha in the mSirt3 promoter. Knockdown of ERRalpha reduced the induction of Sirt3 by PGC-1alpha in C(2)C(12) myotubes. Furthermore, Sirt3 was essential for PGC-1alpha-dependent induction of ROS-detoxifying enzymes and several components of the respiratory chain, including glutathione peroxidase-1, superoxide dismutase 2, ATP synthase 5c, and cytochrome c. Overexpression of SIRT3 or PGC-1alpha in C(2)C(12) myotubes decreased basal ROS level. In contrast, knockdown of mSIRT3 increased basal ROS level and blocked the inhibitory effect of PGC-1alpha on cellular ROS production. Finally, SIRT3 stimulated mitochondrial biogenesis, and SIRT3 knockdown decreased the stimulatory effect of PGC-1alpha on mitochondrial biogenesis in C(2)C(12) myotubes.Our results indicate that Sirt3 functions as a downstream target gene of PGC-1alpha and mediates the PGC-1alpha effects on cellular ROS production and mitochondrial biogenesis. Thus, SIRT3 integrates cellular energy metabolism and ROS generation. The elucidation of the molecular mechanisms of SIRT3 regulation and its physiological functions may provide a novel target for treating ROS-related disease
Blast Shock Wave Mitigation Using the Hydraulic Energy Redirection and Release Technology
A hydraulic energy redirection and release technology has been developed for mitigating the effects of blast shock waves on protected objects. The technology employs a liquid-filled plastic tubing as a blast overpressure transformer to transfer kinetic energy of blast shock waves into hydraulic energy in the plastic tubings. The hydraulic energy is redirected through the plastic tubings to the openings at the lower ends, and then is quickly released with the liquid flowing out through the openings. The samples of the specifically designed body armor in which the liquid-filled plastic tubings were installed vertically as the outer layer of the body armor were tested. The blast test results demonstrated that blast overpressure behind the body armor samples was remarkably reduced by 97% in 0.2 msec after the liquid flowed out of its appropriate volume through the openings. The results also suggested that a volumetric liquid surge might be created when kinetic energy of blast shock wave was transferred into hydraulic energy to cause a rapid physical movement or displacement of the liquid. The volumetric liquid surge has a strong destructive power, and can cause a noncontact, remote injury in humans (such as blast-induced traumatic brain injury and post-traumatic stress disorder) if it is created in cardiovascular system. The hydraulic energy redirection and release technology can successfully mitigate blast shock waves from the outer surface of the body armor. It should be further explored as an innovative approach to effectively protect against blast threats to civilian and military personnel
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