Papers by benjamin guzman
Business process outsourcing analysis among selected employees of Capital One Philippines
espanolCuando se altera el cerebro humano en desarrollo y se produce una disfuncion cognitiva, ne... more espanolCuando se altera el cerebro humano en desarrollo y se produce una disfuncion cognitiva, neurologica o psiquiatrica, se originan los Trastornos del Neurodesarrollo, teniendo el Trastorno del Espectro Autista (TEA) un lugar destacado. La prevalencia del TEA es de 1 cada 68 ninos, aunque se discuten las variaciones dependiendo la region y la forma de medicion. Esta revision comprende, en parte, las principales caracteristicas y problematicas alrededor del desarrollo biologico del cerebro desde el punto de vista genetico. Sin embargo, es destacable el factor ambiental incidente de los genes, que tiene influencia pequena a moderada, aunque a la hora de marcar un desencadenante genetico o ambiental clave, existe una gran heterogeneidad etiologica del TEA. Por otra parte, en este trabajo se abarcaran cambios estructurales y funcionales en el sistema nervioso central, analizando las caracteristicas neurofisiologicas y morfologicas que intervienen en el trastorno. Asi mismo, se analiz...
Ticket vending machine (TVM) and automated fare collection system–Point of sale (AFCS-POS) are tw... more Ticket vending machine (TVM) and automated fare collection system–Point of sale (AFCS-POS) are two new technologies in the Philippines’ train ticketing system. After a year of implementation for the newly deployed ticketing system in Metro Rail Transit (MRT), research shows that there have been no usability evaluation on the new system to evaluate for potential issues and user interface problems. Based on observation and interviews, about 17.5% of train passengers are still having difficulty with using the ticket vending machine and is repulsive to use it for buying ticket thereby increasing the workload for AFCS-POS machine specialists. The study focuses on three aspects of the TVM and AFCS-POS usability measures, (1) effectiveness, (2) efficiency and (3) satisfaction, as defined by ISO 9241-11. Usability analysis showed that effectiveness of the two systems was above average. Efficiency of AFCS-POS is significantly higher than TVM. Some of the first time TVM users were having a di...
A method for a primary frequency control through joint control of combined gas and steam turbine
Gemeinsames, asymmetrisches Kontrollverfahren fur die primare Frequenzregelung (PFR) in Kombikraf... more Gemeinsames, asymmetrisches Kontrollverfahren fur die primare Frequenzregelung (PFR) in Kombikraftwerken (Gas- und Dampf-Kraftwerken) fur Stromerzeugung, mit wenigstens einer Gasturbine und einer Dampfturbine, wobei die Dampfturbine des kombinierten Arbeitsprozesses sich an der primaren Frequenzregelung beteiligt, und zwar uber Speicherung von Rotationsenergie durch Drosselung der Regelventile mit z. B. dem Verfahren des Patents USA 6.609.361, und wobei die Abhitz-Kessel und dementsprechend die Dampfturbine des kombinierten Prozesses mit drei verschiedenen Dampfdrucken arbeitet (Hochdruckdampf, Mitteldruckdampf und Niederdruckdampf) und einen Bypass mit einem Kontroll-Bypassventil vom Hochdruckkreislauf zum Mitteldruckkreislauf aufweist, wodurch die Gasturbinen die erzeugte Nutzleistung steigern und gleichzeitig ihre fur die PFR bestimmte Rotationsenergiereserve reduzieren. Die Dampfturbine verfugt aber uber eine zusatzliche Rotationsenergiereserve fur den PFR-Prozess, um das in den...
Journal of Allergy and Clinical Immunology, 2020
Human rhinovirus (RV) is a major cause of common cold and triggers acute episodes of asthma. Litt... more Human rhinovirus (RV) is a major cause of common cold and triggers acute episodes of asthma. Little is known about T-cell mechanisms of cross-protection to different RV strains. We aimed to rigorously interrogate virus-specific T cells in a sequential experimental infection model in humans. METHODS: Healthy subjects were infected with RV-A16 and rechallenged 15 weeks later with either RV-A16 or RV-A39. Circulating T-cells were sampled over 30 weeks, including peak effector and convalescent infection phases. T cells were phenotyped using a 24-marker spectral flow cytometry panel including up to three RV peptide/MHCII tetramers. Computational tools, including uniform manifold approximation and projection (UMAP), k-nearest neighbor (KNN), and marker enrichment modeling (MEM), were used to quantify signature features of RV-specific T cells and compare them to other T cells in phenotypic neighborhoods either enriched or lacking in RV-specific T cells. RESULTS: Before RV challenge, virus-specific T cells were predominanty CCR5 + PD-1 + central memory and follicular helper (Tfh) cells. During peak effector phases, phenotypically distinct CD4 + T cell types became enriched for RV-specific T cells, including proliferating (Ki67 +) activated Th1 (CCR7 low , CD127 low , CXCR3 + , CD95 + , CD38 + , ICOS + , Tbet + , Tcf-1 +) and Tfh (CCR7 low , CD127 low , PD-1 hi , CXCR5 + , ICOS + , CD38 + , CD95 + , Tcf-1 +) cells. T-cells expanded up to 10-fold, returned to baseline levels during convalescence, and were re-boosted upon re-challenge with either RV strain. Whereas T-cells targeting specific RV epitopes markedly expanded, those targeting other epitopes did not, despite activation during both effector phases. CONCLUSIONS: By integrating high-dimensional phenotyping and computational methods we can reliably identify T-cell hallmarks of protection to different RV strains.
Achieving a primary frequency response with CCGT steam turbines
Modern Power Systems, 2002
Genelba power plant has been offering primary frequency regulation (PFR) to the highly competitiv... more Genelba power plant has been offering primary frequency regulation (PFR) to the highly competitive Argentina electricity market without sacrificing gas turbine capacity. During two years of operation this innovative approach, entirely realised by plant staff, has proved effective and lucrative.
Method of providing asymmetric joint control for primary frequency regulation in combined-cycle power plants
Sistema de prevención, mitigación y alerta temprana de riesgos por eventos naturales en El Salvador
Primary Frequency Regulation Method Through Joint Control in Combined Cycle Turbines
Salud Publica Mex, Oct 1, 1991
potencial que la teoría & la transición en salud encierra para comprender y transformar la crecie... more potencial que la teoría & la transición en salud encierra para comprender y transformar la creciente complejidad de nuestros tiempos. for undersandhg and transformhg the growing complerity of our tima. Palabras clave: transición en salud, transición epidemiológica, determi-Key wonis: health transition, epidemiologic transition, health determinantes de la salud, mortalidad, morbilidad nana, mortality, morbidity 'C.
Emociones y Productividad
Transplantation Proceedings, 2000
Physics Letters B, 2010
We present the result of a search for a massive color-octet vector particle, (e.g. a massive gluo... more We present the result of a search for a massive color-octet vector particle, (e.g. a massive gluon) decaying to a pair of top quarks in proton-antiproton collisions with a center-of-mass energy of 1.96 TeV. This search is based on 1.9 fb −1 of data collected using the CDF detector during Run II of the Tevatron at Fermilab. We study tt events in the lepton+jets channel with at least one btagged jet. A massive gluon is characterized by its mass, decay width, and the strength of its coupling to quarks. These parameters are determined according to the observed invariant mass distribution of top quark pairs. We set limits on the massive gluon coupling strength for masses between 400 and 800 GeV/c 2 and width-to-mass ratios between 0.05 and 0.50. The coupling strength of the hypothetical massive gluon to quarks is consistent with zero within the explored parameter space.
Physical Review Letters, 2010
Physical Review Letters, 2010
We combine searches by the CDF and D0 Collaborations for a Higgs boson decaying to W þ W À. The d... more We combine searches by the CDF and D0 Collaborations for a Higgs boson decaying to W þ W À. The data correspond to an integrated total luminosity of 4.8 (CDF) and 5.4 (D0) fb À1 of p p collisions at ffiffi ffi s p ¼ 1:96 TeV at the Fermilab Tevatron collider. No excess is observed above background expectation, and resulting limits on Higgs boson production exclude a standard model Higgs boson in the mass range 162-166 GeV at the 95% C.L.
Physical Review D, 2010
We report the observation of electroweak single top quark production in 3:2 fb À1 of p " p collis... more We report the observation of electroweak single top quark production in 3:2 fb À1 of p " p collision data collected by the Collider Detector at Fermilab at ffiffi ffi s p ¼ 1:96 TeV. Candidate events in the W þ jets topology with a leptonically decaying W boson are classified as signal-like by four parallel analyses based on likelihood functions, matrix elements, neural networks, and boosted decision trees. These results are combined using a super discriminant analysis based on genetically evolved neural networks in order to improve the sensitivity. This combined result is further combined with that of a search for a single top quark signal in an orthogonal sample of events with missing transverse energy plus jets and no charged lepton. We observe a signal consistent with the standard model prediction but inconsistent with the background-only model by 5.0 standard deviations, with a median expected sensitivity in excess of 5.9 standard deviations. We measure a production cross section of 2:3 þ0:6 À0:5 ðstat þ sysÞ pb, extract the value of the Cabibbo-Kobayashi-Maskawa matrix element jV tb j ¼ 0:91 þ0:11 À0:11 ðstat þ sysÞ AE 0:07 ðtheoryÞ, and set a lower limit jV tb j > 0:71 at the 95% C.L., assuming m t ¼ 175 GeV=c 2 .
Physical Review D, 2010
We combine results from searches by the CDF and D0 collaborations for a standard model Higgs boso... more We combine results from searches by the CDF and D0 collaborations for a standard model Higgs boson (H) in the process gg ! H ! W þ W À in p " p collisions at the Fermilab Tevatron Collider at ffiffi ffi s p ¼ 1:96 TeV. With 4:8 fb À1 of integrated luminosity analyzed at CDF and 5:4 fb À1 at D0, the 95% confidence level upper limit on ðgg ! HÞ Â BðH ! W þ W À Þ is 1.75 pb at m H ¼ 120 GeV, 0.38 pb at m H ¼ 165 GeV, and 0.83 pb at m H ¼ 200 GeV. Assuming the presence of a fourth sequential generation of fermions with large masses, we exclude at the 95% confidence level a standard-modellike Higgs boson with a mass between 131 and 204 GeV.
Physical Review D, 1999
We report a measurement of the top quark mass using six candidate events for the process pp → tt ... more We report a measurement of the top quark mass using six candidate events for the process pp → tt + X → + νb − νb + X, observed in the DØ experiment at the Fermilab pp collider. Using maximum likelihood fits to the dynamics of the decays, we measure a mass for the top quark of m t = 168.4 ± 12.3 (stat)± 3.6 (syst) GeV. We combine this result with our previous measurement in the tt → + jets channel to obtain m t = 172.1 ± 7.1 GeV as the best value of the mass of the top quark measured by DØ.
An Insight into Early Reproductive Processes through thein VivoModel of Ovum Donation
The Journal of Clinical Endocrinology & Metabolism, 1991
To gain insight into early reproductive processes we have prospectively designed ovum donation pr... more To gain insight into early reproductive processes we have prospectively designed ovum donation protocols to elucidate several phenomena relating to embryo implantation and pregnancy sustenance. Artificial endometrial cycles with variable follicular phases were induced in 60 recipients by sequential estrogen and progesterone. A total of 964 oocytes were retrieved throughout 43 ovum donation attempts, for an average of 22.4 (range, 16-41) eggs/retrieval. The overall delivery rate per egg retrieval (donors and recipients combined) was 72.1% (31 of 43). The shortest estrogen stimulation (short follicular phase) resulting in ongoing pregnancies was 5 days in duration, while the longest (long follicular phase) was 35 days in duration before progesterone initiation. Utilization of variable length follicular phases, artificially extended the stage of endometrial receptivity to over 4 weeks. To assess the window of implantation, same age embryos were transferred onto endometrium of different maturational stages. Pregnancies were documented with embryo transfers between luteal day 1 (day 15) to luteal day 6 (day 20), extending the window of implantation in the human to at least 6 consecutive days. To evaluate the relative contribution of oocyte quality and endometrial receptivity to pregnancy outcome, common source ova were transferred onto endometrium with variable hormonal exposure. Despite the drastically different follicular phase estradiol levels and periods of exposure, similar delivery rates were attained in donor cycles (29.4%) and recipient cycles during short follicular phases (29.6%). Slightly higher delivery rates (39.4%) were observed with long follicular phases. The comparable pregnancy rates in donors and recipients are attributed to the common source oocytes regardless of endometrial stimulation.
Invertebrate Biology, 2012
The presence of sibling species within the marine gastropod genus Crepipatella has complicated th... more The presence of sibling species within the marine gastropod genus Crepipatella has complicated the taxonomy of members of the group. Since the establishment of the genus, 15 species have been described, but recent studies have indicated that there are only five valid species, two of which inhabit the coasts of Chile, namely C. dilatata and C. fecunda. The two species are morphologically indistinguishable as adults, but can be differentiated on the basis of their encapsulated developmental stages. The primary aim of this study was to reconstruct phylogeny within the genus, and to establish species limits of C. dilatata and C. fecunda, using mitochondrial DNA data. To this end, we used maximum parsimony, maximum likelihood, and Bayesian inference to reconstruct phylogenies using 589 bp of the cytochrome oxidase I (COI) gene. The mtDNA phylogenies were then used as input in a general mixed Yule-coalescent (GMYC) analysis to estimate species boundaries. In addition, quarter likelihood mapping was used to test a posteriori the confidence of inner branch patterns in the phylogenetic tree. Both DNA tree-based and GMYC methods provide support for five isolated lineages within this species complex. Our data also suggest that Late Pleistocene and Holocene fragmentation and subsequent range expansion events may have shaped contemporary genetic patterns of Crepipatella in South America.
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Papers by benjamin guzman