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Sistema de deteção de eventos adversos baseado num data warehouse

Lourenço, João Pedro Gil
Fonte: Universidade Nova de Lisboa Publicador: Universidade Nova de Lisboa
Tipo: Dissertação de Mestrado
Publicado em //2014 POR
Relevância na Pesquisa
26.56%
RESUMO - A Segurança do Doente tem assumido uma relevância crescente nas organizações de saúde, resultado da divulgação de diversos estudos que revelaram a magnitude deste problema e simultaneamente, de uma maior pressão por parte da opinião pública e da comunicação social. Este estudo pretende desenvolver e avaliar a performance de um sistema eletrónico de deteção de eventos adversos, baseado num Data Warehouse, por comparação com os resultados obtidos pela metodologia tradicional de revisão dos registos clínicos. O objetivo principal do trabalho consistiu em identificar um conjunto de triggers / indicadores de alerta que permitam detetar potenciais eventos adversos mais comuns. O sistema desenvolvido apresentou um Valor Preditivo Positivo de 18.2%, uma sensibilidade de 65.1% e uma especificidade de 68.6%, sendo constituído por nove indicadores baseados em informação clínica e 445 códigos do ICD-9-CM, relativos a diagnósticos e procedimentos. Apesar de terem algumas limitações, os sistemas eletrónicos de deteção de eventos adversos apresentam inúmeras potencialidades, nomeadamente a utilização em tempo real e em complemento a metodologias já existentes. Considerando a importância da problemática em análise e a necessidade de aprofundar os resultados obtidos neste trabalho de projeto...

Triggers of daily life ischaemia

Freedman, S; Wong, C
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/1998 EN
Relevância na Pesquisa
26.63%
Objective—To determine the usual triggers of silent and symptomatic ischaemia.
Design—Patients wore an ambulatory recorder for 48 hours. The device emitted a tone on detection of ischaemia and patients noted activities, feelings, and symptoms so that ischaemia could be attributed to one of four triggers: physical stress, mental stress, combined physical/mental stress, or no stressor.
Setting—Home environment.
Patients—Patients (n = 38) with stable coronary disease, positive exercise electrocardiography, and ischaemic episodes on ambulatory electrocardiography.
Main outcome measure—Matching ischaemic episodes with perceived triggers.
Results—Altogether 257 ischaemic episodes (53% silent) were documented. Triggers were: physical stress, 56%; mental stress, 5%; combined physical/mental stress, 8%; no identifiable trigger, 31%. Episodes associated with mental or no stress were more often silent (69% and 75%, respectively) than those associated with physical stress (45%, p < 0.01), while combined physical/mental stress episodes were usually symptomatic (10% silent, p < 0.01 v other stressors). Although physical stress was less commonly a trigger of silent ischaemia than angina (47% v 65%, p < 0.01), it was still the predominant trigger of silent ischaemia. There was no identifiable trigger in 45% of silent and only 17% of anginal episodes (p < 0.01). Only nine silent episodes involved mental stress alone as a trigger.
Conclusions—Daily life ischaemia is usually triggered by physical activity. Mental stress alone is an uncommon trigger of either silent or symptomatic ischaemia...

Herpes Simplex Virus Immediate-Early Protein ICP22 Triggers Loss of Serine 2-Phosphorylated RNA Polymerase II▿

Fraser, Kathryn A.; Rice, Stephen A.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
26.56%
During eukaryotic mRNA transcription, the synthetic activity and mRNA processing factor interactions of RNA polymerase II (RNAP II) are regulated by phosphorylation of its carboxyl-terminal domain (CTD), with modification occurring primarily on serines 2 and 5 of the CTD. We previously showed that herpes simplex virus type 1 (HSV-1) infection rapidly triggers the loss of RNAP II forms bearing serine 2 phosphorylation (Ser-2P RNAP II). Here we show that the HSV-1 immediate-early (IE) protein ICP22 is responsible for this effect during the IE phase of infection. This activity does not require the viral UL13 protein kinase, which is required for several other regulatory functions of ICP22. Additionally, we show that transient expression of ICP22 can trigger the loss of Ser-2P RNAP II in transfected cells. Thus, the ability of ICP22 to cause the loss of Ser-2 RNAP II does not require other viral factors or the context of the infected cell. Expression of the HSV-1 ICP22-related protein US1.5, which corresponds to residues 147 to 420 of ICP22, also triggers a loss of Ser-2P RNAP II in transfected cells, whereas expression of the varicella-zoster virus ICP22 homolog, ORF63, does not. Our study also provides evidence for a second, viral late gene-dependent pathway that triggers loss of Ser-2P RNAP II in infected cells...

Sunlight Triggers Cutaneous Lupus through a Colony Stimulating Factor-1 (CSF-1) Dependent Mechanism in MRL-Faslpr mice

Menke, Julia; Hsu, Mei-Yu; Byrne, Katelyn T.; Lucas, Julie A.; Rabacal, Whitney A.; Croker, Byron P.; Zong, Xiao-Hua; Stanley, E. Richard; Kelley, Vicki R.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 15/11/2008 EN
Relevância na Pesquisa
26.56%
Sunlight (UVB) triggers cutaneous (CLE) and systemic lupus through an unknown mechanism. We tested the hypothesis that UVB triggers CLE through a CSF-1-dependent, macrophage (Mø) -mediated mechanism in MRL-Faslpr mice. By constructing mutant MRL-Faslpr strains expressing varying levels of CSF-1 (high, intermediate, none), and use of an ex-vivo gene transfer to deliver CSF-1 intra-dermally, we determined that CSF-1 induces CLE in lupus-susceptible, MRL-Faslpr mice, but not in lupus-resistant, BALB/c mice. Notably, UVB incites an increase in Mø, apoptosis in the skin and CLE in MRL-Faslpr, but not in CSF-1-deficient MRL-Faslpr mice. Furthermore, UVB did not induce CLE in BALB/c mice. Probing further, UVB stimulates CSF-1 expression by keratinocytes leading to recruitment and activation of Mø that, in turn, release mediators, which induce apoptosis in keratinocytes. Thus, sunlight triggers a CSF-1-dependent, Mø-mediated destructive inflammation in the skin leading to CLE in lupus-susceptible MRL-Faslpr, but not lupus-resistant BALB/c mice. Taken together, we envision CSF-1 as the “match” and lupus-susceptibility as the “tinder” leading to CLE.

Expression Strategies for Short Hairpin RNA Interference Triggers

ROSSI, JOHN J.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/2008 EN
Relevância na Pesquisa
26.56%
Since the discovery that the triggers for RNA interference (RNAi), small interfering RNAs, could mediate silencing in mammalian cells without triggering a toxic response, RNAi has become the standard tool for sequence-specific knockdown of gene expression in molecular biology. This is due in part to the development of methods for promoter-based expression of RNAi triggers that can mediate stable silencing in mammalian cells. Numerous systems with slightly different characteristics exist, but despite incredible progress in a field that moves very rapidly, challenges still remain. The biggest challenge is to successfully and safely apply RNAi in vivo. Aside from potential issues of delivery, which is one of the most important considerations, successful application of short hairpin RNAs (shRNAs) in vivo requires expression systems that yield potent and specific knockdown of the target in the absence of toxicity. With a couple of exceptions, the current systems available for shRNA expression have not generally resulted in unexpected toxicities, while still providing strong knockdown of the intended targets; however, we do not know enough about how sequence-specific off-target effects will affect various cell and tissue types, or to what extent ectopic expression of RNAi triggers will perturb the endogenous RNAi mechanisms.

Home is Where the Triggers Are: Increasing Asthma Control by Improving the Home Environment

Krieger, James
Fonte: Mary Ann Liebert, Inc. Publicador: Mary Ann Liebert, Inc.
Tipo: Artigo de Revista Científica
Publicado em /06/2010 EN
Relevância na Pesquisa
26.56%
Asthma remains the most common chronic condition of childhood. Strong evidence has linked exposure to allergens and other triggers commonly found in homes to allergen sensitization and asthma incidence and morbidity. A growing body of evidence has demonstrated that a home visit strategy that includes an environmental component that addresses multiple triggers through multiple interventions is effective. Such home visits reduce exposure to triggers, decrease symptoms and urgent health-care use, and increase quality of life. To make home visits widely available will require health-care payor reimbursement, government and health plan funding, training and certification of home visitors, and active referrals from health-care providers. However, a strategy based solely on education and behavior change is limited, because it cannot adequately reduce exposures due to adverse housing conditions. Therefore, approaches that address substandard housing are needed. These include remediation of existing housing and construction of new asthma-friendly homes. Most studies of remediation have made relatively narrow and focused improvements, such as insulation, heating, or ventilation. Outcomes have been mixed. Studies of new asthma-friendly homes are in their infancy...

Alcohol and Vagal Tone as Triggers for Paroxysmal Atrial Fibrillation

Mandyam, Mala C.; Vedantham, Vasanth; Scheinman, Melvin M.; Tseng, Zian H.; Badhwar, Nitish; Lee, Byron K.; Lee, Randall J.; Gerstenfeld, Edward P.; Olgin, Jeffrey E.; Marcus, Gregory M.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
26.73%
Alcohol and vagal activity may be important triggers for paroxysmal atrial fibrillation (PAF), but it remains unknown if these associations occur more often than would be expected by chance alone due to the lack of a comparator group in previous studies. We compared the self-reported frequency of these triggers in PAF patients to those with other supraventricular tachycardias (SVT). Consecutive consenting patients presenting for electrophysiology procedures at a single University Medical Center underwent a structured interview regarding arrhythmia triggers. Two hundred and twenty three patients with a documented arrhythmia (133 with PAF and 90 with SVT) completed the survey. After multivariable adjustment, PAF patients had a 4.42 greater odds (95% CI 1.35–14.44) of reporting alcohol consumption (p=0.014) and a 2.02 greater odds (95% CI 1.02–4.00) of reporting vagal activity (p=0.044) as an arrhythmia trigger compared to SVT patients. Among PAF patients, drinking primarily beer was associated with alcohol as a trigger (odds ratio [OR] 4.49, 95% CI 1.41–14.28, p=0.011), while younger age (OR 0.68, 95% CI 0.49–0.95, p=0.022) and a family history of atrial fibrillation (AF) (OR 5.73, 95% CI 1.21–27.23, p=0.028) were each independently associated with having vagal activity provoke an episode. PAF patients with alcohol triggers were more likely to have vagal triggers (OR 10.32...

Identified risk factors and adolescents’ beliefs about triggers for headaches: results from a cross-sectional study

Milde-Busch, Astrid; Straube, Andreas; Heinen, Florian; von Kries, Rüdiger
Fonte: Springer Milan Publicador: Springer Milan
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
26.69%
Although there are few studies on adolescents’ beliefs about triggers of headache, none of these compared the associations between perceived and observed triggers. This study aimed at comparing the prevalence of self-perceived and observed risk factors for headache among adolescents. Adolescents from the 10th and 11th grades of high schools answered questionnaires on their headaches and on potential risk factors regarding lifestyle, stress and muscle pain. Individuals reporting to have experienced headache in the preceding 6 months were asked to report what they believed to cause their headache (self-perceived triggers). 1,047 (83 %) of 1,260 adolescents reported headaches. Stress, lack of sleep and too much school work were the most frequently reported self-perceived triggers of headache; in contrast the statistical analysis identified alcohol and coffee consumption, smoking, neck pain, stress and physical inactivity as risk factors for headache. Among individuals with headache, 48 % believed that stress might trigger their headaches, while increased stress scores were only observed in 23 %. In contrast, while 7, 4, 0.3 and 0 % of individuals reporting headache considered consumption of too much alcohol, neck pain, physical inactivity and consumption of coffee might trigger their headache...

Emotional triggers in myocardial infarction: do they matter?

Edmondson, Donald; Newman, Jonathan D.; Whang, William; Davidson, Karina W.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
26.76%
Considerable excitement and interest have arisen recently concerning the role that acute emotional triggers may play in precipitating a myocardial infarction (MI). Observational studies have found repeatedly that patients report excessive anger, anxiety, sadness, grief, or acute stress immediately prior to onset of MI, and recent meta-analyses summarizing these findings reported strong associations between MI occurrence and many of these acute emotions. However, it is unclear whether and through what mechanisms acute emotional triggers might influence MI, and whether there is any clinical utility in knowing if or how emotions trigger MI. We debate whether emotional triggers matter by reviewing the recent evidence for the association between acute emotional triggers and MI and by describing the potential pathophysiological characteristics and mechanisms underlying this association and the preventive strategies that could be used to mitigate the risk of acute MI. We also examine whether the study of emotional triggers could influence clinical risk management or changes in clinical practice/management. We offer suggestions for research that might shed light on whether emotional triggers could initiate a paradigm shift in preventive cardiology...

Perceived Triggers of Asthma: Key to Symptom Perception and Management

Janssens, Thomas; Ritz, Thomas
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /09/2013 EN
Relevância na Pesquisa
26.63%
Adequate asthma management depends on an accurate identification of asthma triggers. A review of the literature on trigger perception in asthma shows that individuals vary in their perception of asthma triggers and that the correlation between self-reported asthma triggers and allergy tests is only modest. In this paper, we provide an overview of psychological mechanisms involved in the process of asthma triggers identification. We identify sources of errors in trigger identification and targets for behavioral interventions that aim to improve the accuracy of asthma trigger identification and thereby enhance asthma control.

Resident-to-Resident Violence Triggers in Nursing Homes

Snellgrove, Susan; Beck, Cornelia; Green, Angela; McSweeney, Jean C.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
26.56%
Certified nurses’ assistants (CNAs) employed by a rural nursing home in Northeast Arkansas described their perceptions of resident-to-resident violence in order to provide insight on factors, including unmet needs, that may trigger the phenomenon. Semistructured interviews were conducted with 11 CNAs. Data were analyzed using content analysis and constant comparison. Two categories of triggers emerged from the data—active and passive. Active triggers involved the actions of other residents that were intrusive in nature, such as wandering into a residents’ personal space, taking a resident’s belongings, and so forth. Passive triggers did not involve the actions of residents but related to the internal and external environment of the residents. Examples were factors such as boredom, competition for attention and communication difficulties. Results indicate that there are factors, including unmet needs within the nursing home environment that may be identified and altered to prevent violence between residents.

Soft but Strong. Neg-Raising, Soft Triggers, and Exhaustification

Romoli, Jacopo
Fonte: Harvard University Publicador: Harvard University
Tipo: Thesis or Dissertation
EN_US
Relevância na Pesquisa
36.44%
In this thesis, I focus on scalar implicatures, presuppositions and their connections. In chapter 2, I propose a scalar implicature-based account of neg-raising inferences, standardly analyzed as a presuppositional phenomenon (Gajewski 2005, 2007). I show that an approach based on scalar implicatures can straightforwardly account for the differences and similarities between neg-raising predicates and presuppositional triggers. In chapters 3 and 4, I extend this account to “soft” presuppositions, a class of presuppositions that are easily suspendable (Abusch 2002, 2010). I show how such account can explain the differences and similarities between this class of presuppositions and other presuppositions on the one hand, and scalar implicatures on the other. Furthermore, I discuss various consequences that it has with respect to the behavior of soft presuppositions in quantificational sentences, their interactions with scalar implicatures, and their effects on the licensing of negative polarity items. In chapter 5, I show that by looking at the interaction between presuppositions and scalar implicatures we can solve a notorious problem which arises with conditional sentences like (1) (Soames 1982, Karttunen and Peters 1979). The main issue with (1) is that it is intuitively not presuppositional and this is not predicted by any major theory of presupposition projection. (1) I’ll go...

Reducing patients’ exposures to asthma and allergy triggers in their homes: an evaluation of effectiveness of grades of forced air ventilation filters

Brown, Kathleen Ward; Minegishi, Taeko; Allen, Joseph G.; McCarthy, John F.; Spengler, John D.; MacIntosh, David L.
Fonte: Informa Healthcare USA, Inc. Publicador: Informa Healthcare USA, Inc.
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
36.69%
Objective: Many interventions to reduce allergen levels in the home are recommended to asthma and allergy patients. One that is readily available and can be highly effective is the use of high performing filters in forced air ventilation systems. Methods: We conducted a modeling analysis of the effectiveness of filter-based interventions in the home to reduce airborne asthma and allergy triggers. This work used “each pass removal efficiency” applied to health-relevant size fractions of particles to assess filter performance. We assessed effectiveness for key allergy and asthma triggers based on applicable particle sizes for cat allergen, indoor and outdoor sources of particles <2.5 µm in diameter (PM2.5), and airborne influenza and rhinovirus. Results: Our analysis finds that higher performing filters can have significant impacts on indoor particle pollutant levels. Filters with removal efficiencies of >70% for cat dander particles, fine particulate matter (PM2.5) and respiratory virus can lower concentrations of those asthma triggers and allergens in indoor air of the home by >50%. Very high removal efficiency filters, such as those rated a 16 on the nationally recognized Minimum Efficiency Removal Value (MERV) rating system...

Triggers for emergency team activation: A multicenter assessment

Chen, J.; Bellomo, R.; Hillman, K.; Flabouris, A.; Finfer, S.
Fonte: W B Saunders Co Publicador: W B Saunders Co
Tipo: Artigo de Revista Científica
Publicado em //2010 EN
Relevância na Pesquisa
26.76%
PURPOSE: The purpose of the study was to examine triggers for emergency team activation in hospitals with or without a medical emergency team (MET) system. MATERIALS AND METHODS: Within a cluster randomized controlled trial examining the effect of introducing a MET system, we recorded the triggers for emergency team activation. We compared the proportion and rate of such triggers in hospitals with or without a MET system and in relation to type of hospital, type of patient ward, and time of day. RESULTS: In control hospitals, the most common trigger for emergency team activation was a decrease in Glasgow Coma Score by 2 or more points (45.6%), whereas in MET hospitals, it was the fact that staff members were "worried" or the call occurred despite the lack of a "specified reason" (39.3%). In particular, MET hospitals were 35 times more likely to make a call because of staff being "worried" about the patient (14.1% vs 0.4%, P < .001). Control hospitals were also significantly more likely to call an emergency team because of a deteriorating respiratory (P = .003) or pulse (P < .001) rate, more calls had at least 3 triggers for activation (20.8% vs 10.2%, P = .036), and the average number of triggers per call was significantly higher (P = .013). Nonmetropolitan hospitals were more likely to call an emergency team because of respiratory rate abnormalities (33.6% vs 23.2%...

Using UML’s Sequence Diagrams for Representing Execution Models Associated to Triggers

Al-Jumaily, Harith T.; Pablo Sánchez, César de; Cuadra, Dolores; Martínez, Paloma
Fonte: Springer Publicador: Springer
Tipo: info:eu-repo/semantics/conferenceObject; info:eu-repo/semantics/bookPart Formato: application/pdf
Publicado em /09/2006 ENG
Relevância na Pesquisa
26.69%
Using active rules or triggers to verify integrity constraints is a serious and complex problem because these mechanisms have behaviour that could be difficult to predict in a complex database. The situation is even worse as there are few tools available for developing and verifying them. We believe that automatic support for trigger development and verification would help database developers to adopt triggers in the database design process. Therefore, in this work we suggest a visualization add-in tool that represents and verifies triggers execution by using UML’s sequence diagrams. This tool is added in RATIONAL ROSE and it simulates the execution sequence of a set of triggers when a DML operation is produced. This tool uses the SQL standard to express the triggers semantics and execution.; This work is part of the project "Software Process Management Platform: modelling, reuse and measurement". TIN2004/07083.; 11 pages, 3 figures.-- Contributed to: 23rd British National Conference on Databases (BNCOD 23, Belfast, Northern Ireland, UK, July 18-20, 2006).

Organizational Disruptions and Triggers for Divergent Sensemaking

Weber, Matthew S.; Thomas, Gail Fann; Stephens, Kimberlie J.
Fonte: Escola de Pós-Graduação Naval Publicador: Escola de Pós-Graduação Naval
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.44%
In recent years, scholars and practitioners alike have sought to better understand the emergent communicative processes involved in the implementation of strategic organizational initiatives. In response, this article builds on sensemaking and sensegiving theory to understand the interactions that developed between internal and external stakeholders in response to a post-9/11 change in the Maritime Transportation Security Act. A detailed, emergent account of a failed initiative was derived from public comments in the Federal Register, transcripts from public meetings, newspaper articles, and semistructured interviews with key internal informants. In-depth analysis of these data allowed us to examine a divergent sensemaking process and identify four critical triggers that led to a communication breakdown: (a) unidirectional and parsimonious communication, (b) multifaceted understandings of organizational identities, (c) misaligned cues, and (d) an emergence of interorganizational sensemaking. A first-order analysis presents data from an in-depth case analysis, and a second-order analysis uses the analysis to develop a divergent sensemaking conceptual model. From a strategic communication perspective, our findings demonstrate the importance of taking a broad perspective of the legitimate participants in a sensemaking process...

The Processing of 'wieder' ('again') and Other Presupposition Triggers

Tiemann, Sonja
Fonte: Universität Tübingen Publicador: Universität Tübingen
Tipo: Dissertation; info:eu-repo/semantics/doctoralThesis
EN
Relevância na Pesquisa
26.63%
This dissertation presents three experiments on the processing of the German presupposition trigger wieder (`again'). In the first experiment, the focus is on how a simple sentence containing again is processed during reading when the presupposition is given in the context in contrast to when it is not given. On the basis of these results, I suggest that people do not accommodate a presupposition if not absolutely necessary. This leads me to postulate the maxim Minimize Accommodation. I further argue that assuming such a maxim has consequences for presupposition trigger other than again. The processing hypotheses for other presupposition triggers deduced from the results of the first experiment are tested in the second experiment. They are contrasted with hypotheses that can be drawn from other, more pragmatic presupposition theories. These two hypotheses are tested with a variety of presuppositions triggers (factives, change of state verbs, iteratives, additives, definites) in a self-paced reading experiment. The results reveal interesting differences between the triggers which fit most easily with a theory which assumes a lexical source for presuppositions. In the third experiment, I turn to the complex issue of presupposition projection out of quantified expressions. Two theories on this phenomenon are contrasted and tested in an eye-tracking experiment with the triggers again and the definite determiner. The results show that neither of the discussed theories can account for the empirical pattern...

Calorimeter-Based Triggers at the ATLAS Detector for Searches for Supersymmetry in Zero-Lepton Final States

Mann, Alexander
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 22/05/2012
Relevância na Pesquisa
26.63%
This thesis consists of three closely related parts. An analysis of data recorded by the ATLAS detector in 2010 in proton-proton collisions at a center-of-mass energy of 7 TeV with an integrated luminosity of 33.4/pb is performed, searching for supersymmetric final states containing jets and missing transverse energy and no electrons or muons (zero-lepton channel). No excess over the Standard Model background expectation is observed. Using the CLs and PLR methods, exclusion limits are set in two different supergravity models. These considerably extend the excluded parameter ranges from earlier experiments. The rates and efficiencies of triggers based on combined signatures with jets plus missing transverse energy in ATLAS are studied, which are the primary triggers for the search for Supersymmetry in the zero-lepton channel. For the measurement of the efficiencies in data collected in 2010 and 2011, the bootstrap method is applied. Different sample triggers based on jets and missing transverse energy are compared and their efficiencies are measured. A reweighting approach is used to correct for the bias from the propagation of the uncertainties in the bootstrap method. A universal model is developed to describe the contribution of fake missing transverse energy from resolution effects to the rates of missing transverse energy triggers as function of the level of in-time pile-up...

A Robust Filter for the BeppoSAX Gamma Ray Burst Monitor Triggers

Feroci, M.; Bianco, C. L.; Lazzarotto, F.; Mattei, A.; Ventura, G.; Costa, E.; Frontera, F.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 23/12/1999
Relevância na Pesquisa
26.63%
The BeppoSAX Gamma Ray Burst Monitor (GRBM) is triggered any time a statistically significant counting excess is simultaneously revealed by at least two of its four independent detectors. Several spurious effects, including highly ionizing particles crossing two detectors, are recorded as onboard triggers. In fact, a large number of false triggers is detected, in the order of 10/day. A software code, based on an heuristic algorithm, was written to discriminate between real and false triggers. We present the results of the analysis on an homogeneous sample of GRBM triggers, thus providing an estimate of the efficiency of the GRB detection system consisting of the GRBM and the software.; Comment: Proc. 5th Huntsville GRB Symposium

Muons enhancements at sea level in association with Swift-BAT and MILAGRO triggers

Augusto, C. R. A.; Navia, C. E.; Tsui, K. H.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 26/02/2008
Relevância na Pesquisa
26.69%
Recently, triggers occurring during high background rate intervals have been reporter by Swift-BAT Gamma Ray Burst (GRB) detector. Among them, there were two on January 24, two on January 25, and two on February 13, and 18, all in 2008. These Swift-BAT triggers in most cases are probably noise triggers that occurred while Swift was entering the South Atlantic Anomaly (SAA). In fact, we show that they happen during a plentiful precipitation of high energy particles in the SAA, producing muons in the atmosphere detected by two directional telescopes at sea level, inside the SAA region (Tupi experiment). They look like sharp peaks in the muon counting rate. In the same category are two triggers from MILAGRO ground based detector, on January 25 and 31, 2008 respectively. In addition, the trigger coordinates are close to (and, in two cases, inside) the field of view of the telescopes. From an additional analysis in the behavior of the muon counting rate, it is possible to conclude that the events are produced by precipitation of high energy charged particles in the SAA region. Thus, due to its localization, the Tupi experiment constitutes a new sensor of high energy particle precipitation in the SAA, and it can be useful in the identification of some triggers of Gamma Ray Burst detectors.; Comment: 7pages...