159 resultados para Ill-Posed Problem
Resumo:
In clinical practice, a classification of seizures based on clinical signs and symptoms leads to an improved understanding of epilepsy-related issues and therefore strongly contributes to a better patient care. The inverse problem involves inferring the anatomical brain localization of a seizure from the scalp surface EEG, a concept we apply here to correlate seizure origin with seizure semiology. The spheres of sensorium, motor features, consciousness changes and autonomic alterations during ictal and postictal manifestations are reviewed, including several subdivisions used to better categorize particular features. Particular attention is given to behavioral features, as well as to features occurring in idiopathic generalized epileptic syndromes and psychogenic nonepileptic spells.
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Der Aufsatz nähert sich dem Interpretationsproblem des ,Ring', eines seit Forschungsbeginn ausserordentlich konträr diskutierten Textes, aus wissenschaftsanalytischer Perspektive. Er führt die Zersplitterung und die Extremisierung der Deutungsansätze, die die breite Forschung zu Wittenwilers Werk kennzeichnet, auf einen vergleichsweise simplen Befund zurück: die ungeklärte Frage nach dem Verhältnis von Komik und Didaktik und der Ernsthaftigkeit des lehrhaften Angebots im ,Ring'. Die so auf grundlegendster Ebene offen gebliebene Erfassung des Textes führt in einen interpretatorischen Leerraum, in dem die widersprüchlichsten, oft wissenschaftsideologisch begründeten Positionen Platz finden. Ihre Analyse zeigt, dass sie sich in wiederkehrende Gruppierungen ordnen. Als Schlüsselglied sowohl der Befunddaten als auch der konträren Vernetzungen von Befund und Deutung wird die wechselnd rote und grüne Initialenlinie der Münchner Handschrift identifiziert. Als im Prolog eingeführte Markierung von Ernst auf der einen und Komik auf der anderen Seite ist sie nicht nur visueller Ausdruck des Deutungsproblems des ,Ring', sondern sie hat es wegen der scheinbaren Unstimmigkeit ihrer Zuweisungen auch wesentlich bedingt. Der Aufsatz zeigt ihren bisher übersehenen Aufschluss für das Verständnis des Werks. Nimmt man die Linie als graphisches Verfahren ernst, stellt sie sich als strukturelle Markierung zum Auffinden von Text im diskontinuierlichen Zugriff dar - nicht aber, wie man sie bisher ausnahmslos verstand, als semantische Kommentierung eines laufenden, kontinuierlich zu lesenden Textes. Die strukturierende Funktion des Farbwechsels ist auf zwei Ebenen nachzuweisen: Auf Makroebene trennen seine Zuweisungen vorwiegend narrative und vorwiegend wissensvermittelnde Grosspartien des ,Ring' durch eine jeweilige Grundfarbe. Auf Mikroebene wird diese Grundfarbe durch die jeweils andere Farbe durchbrochen, um formale Einschnitte wie etwa Sprecherwechsel, Ortswechsel, Handlungsneueinsätze, Beginn und Ende eines eingeschalteten Binnentextes oder einer Sentenz anzuzeigen. Dem Benutzer der autornahen Handschrift sollte so in einem ersten Schritt (makrostrukturell) ermöglicht werden, gezielt auf gewünschte Stellen des Textes zuzugreifen und ihn in einem zweiten Schritt (mikrostrukturell) schneller zu erfassen. Nicht in seiner Umsetzung, sehr wohl aber in seiner Funktion steht dieses ungewöhnliche Layout zeitgenössischen Techniken der Buchgliederung durchaus nahe. Auch im Profil der Zusammenstellung seiner Binnentexte rückt der ,Ring' damit in die Nähe der im Spätmittelalter beliebten Sammelhandschriften mit Ziel einer Wissenssumme, die hier narrativ verbundenen wird. Es scheint, als möchte der ,Ring' in einem ungewöhnlichen Experiment beides sein: Kompilation und Werkganzes, Wissenssammlung und Erzählwerk - Texte und Text. Als Ergebnis einer Neuuntersuchung des Münchner codex unicus des ,Ring' weist der Beitrag schliesslich darauf hin, dass auch zahlreiche Markierungszeichen am Spaltenrand formale und strukturelle Texteinschnitte anzeigen und somit die gleiche Funktion haben wie der Farbwechsel auf Mikroebene. Ein kausaler, produktionstechnischer Zusammenhang zwischen diesen Zeichen und der Verteilung des Farbwechsels ist nicht auszuschliessen, zumal beide Verfahren etwa im letzten Fünftel des Textes zunehmend zusammenfallen. Möglicherweise war nur die makrostrukturelle Funktion des Farbwechsel ursprünglich indendiert und mit der Erläuterung im Prolog bezeichnet, während seine mikrostrukturelle Funktion erst Resultat des Abschreibprozesses ist.
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PURPOSE: The current study tested the applicability of Jessor's problem behavior theory (PBT) in national probability samples from Georgia and Switzerland. Comparisons focused on (1) the applicability of the problem behavior syndrome (PBS) in both developmental contexts, and (2) on the applicability of employing a set of theory-driven risk and protective factors in the prediction of problem behaviors. METHODS: School-based questionnaire data were collected from n = 18,239 adolescents in Georgia (n = 9499) and Switzerland (n = 8740) following the same protocol. Participants rated five measures of problem behaviors (alcohol and drug use, problems because of alcohol and drug use, and deviance), three risk factors (future uncertainty, depression, and stress), and three protective factors (family, peer, and school attachment). Final study samples included n = 9043 Georgian youth (mean age = 15.57; 58.8% females) and n = 8348 Swiss youth (mean age = 17.95; 48.5% females). Data analyses were completed using structural equation modeling, path analyses, and post hoc z-tests for comparisons of regression coefficients. RESULTS: Findings indicated that the PBS replicated in both samples, and that theory-driven risk and protective factors accounted for 13% and 10% in Georgian and Swiss samples, respectively in the PBS, net the effects by demographic variables. Follow-up z-tests provided evidence of some differences in the magnitude, but not direction, in five of six individual paths by country. CONCLUSION: PBT and the PBS find empirical support in these Eurasian and Western European samples; thus, Jessor's theory holds value and promise in understanding the etiology of adolescent problem behaviors outside of the United States.
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This paper applies probability and decision theory in the graphical interface of an influence diagram to study the formal requirements of rationality which justify the individualization of a person found through a database search. The decision-theoretic part of the analysis studies the parameters that a rational decision maker would use to individualize the selected person. The modeling part (in the form of an influence diagram) clarifies the relationships between this decision and the ingredients that make up the database search problem, i.e., the results of the database search and the different pairs of propositions describing whether an individual is at the source of the crime stain. These analyses evaluate the desirability associated with the decision of 'individualizing' (and 'not individualizing'). They point out that this decision is a function of (i) the probability that the individual in question is, in fact, at the source of the crime stain (i.e., the state of nature), and (ii) the decision maker's preferences among the possible consequences of the decision (i.e., the decision maker's loss function). We discuss the relevance and argumentative implications of these insights with respect to recent comments in specialized literature, which suggest points of view that are opposed to the results of our study.
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Objective: There is little evidence regarding the benefit of stress ulcer prophylaxis (SUP) outside critical care setting. Over-prescription of SUP is not devoid of risks. This prospective study aimed to evaluate the use of proton pump inhibitors (PPIs) for SUP in a general surgery department.Methods: Data collection was performed prospectively during an 8-week period on patients hospitalized in a general surgery department (58 beds) by pharmacists. Patients with a PPI prescription for the treatment of ulcers, gastro-oesophageal reflux disease, oesophagitis or epigastric pain were excluded. Patients admitted twice during the study period were not re-included. The American Society of Health-System Pharmacists guidelines on SUP were used to assess the appropriateness of de novo PPI prescriptions.Results: Among 255 consecutive patients in the study, 138 (54%) received a prophylaxis with PPI, of which 86 (62%) were de novo PPI prescriptions. One-hundred twenty-nine patients (94%) received esomeprazole (according to the hospital drug policy). The most frequent dosage was 40 mg/day. Use of PPI for SUP was evaluated in 67 patients. Fifty-three patients (79%) had no risk factors for SUP. Twelve and 2 patients had one or two risk factors, respectively. At discharge, PPI prophylaxis was continued in 34% of patients with a de novo PPI prescription.Conclusion: This study highlights the overuse of PPIs in non-ICU patients and the inappropriate continuation of PPI prescriptions at discharge.Treatment
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ABSTRACT Imipenem plasma-concentrations were measured in 19 critically-ill children (median 0.8 year, range 0.02-12.9 years). Wide inter-individual variations (2-4x at peak and >10x at through concentrations) resulted in unpredictable plasma-levels in several children. To avoid subtherapeutic drug levels we recommend at least 100 mg/kg/day of imipenem-cilastatin in critically-ill children requiring such therapy.
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BACKGROUND: The obective of this study was to perform a cost-effectiveness analysis comparing intermittent with continuous renal replacement therapy (IRRT versus CRRT) as initial therapy for acute kidney injury (AKI) in the intensive care unit (ICU). METHODS: Assuming some patients would potentially be eligible for either modality, we modeled life year gained, the quality-adjusted life years (QALYs) and healthcare costs for a cohort of 1000 IRRT patients and a cohort of 1000 CRRT patients. We used a 1-year, 5-year and a lifetime horizon. A Markov model with two health states for AKI survivors was designed: dialysis dependence and dialysis independence. We applied Weibull regression from published estimates to fit survival curves for CRRT and IRRT patients and to fit the proportion of dialysis dependence among CRRT and IRRT survivors. We then applied a risk ratio reported in a large retrospective cohort study to the fitted CRRT estimates in order to determine the proportion of dialysis dependence for IRRT survivors. We conducted sensitivity analyses based on a range of differences for daily implementation cost between CRRT and IRRT (base case: CRRT day $632 more expensive than IRRT day; range from $200 to $1000) and a range of risk ratios for dialysis dependence for CRRT as compared with IRRT (from 0.65 to 0.95; base case: 0.80). RESULTS: Continuous renal replacement therapy was associated with a marginally greater gain in QALY as compared with IRRT (1.093 versus 1.078). Despite higher upfront costs for CRRT in the ICU ($4046 for CRRT versus $1423 for IRRT in average), the 5-year total cost including the cost of dialysis dependence was lower for CRRT ($37 780 for CRRT versus $39 448 for IRRT on average). The base case incremental cost-effectiveness analysis showed that CRRT dominated IRRT. This dominance was confirmed by extensive sensitivity analysis. CONCLUSIONS: Initial CRRT is cost-effective compared with initial IRRT by reducing the rate of long-term dialysis dependence among critically ill AKI survivors.
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The aim of the present study was to investigate the effects of continuous and acute L-carnitine supplementation of total parenteral nutrition (TPN) on protein and fat oxidation in severe catabolism. A critically ill and severely malnourished male patient received TPN (non protein energy = 41 kcal/kg/day, provided equally as fat and glucose) over 38 days, without L-carnitine for 23 days and with carnitine supplements (15 mg/kg/day) for the following 15 days. Subsequently, he was given carnitine-free enteral nutrition for 60 more days. A four-hour infusion of 100 mg L-carnitine was given on day 11 of each TPN period. Indirect calorimetry was carried out after 11 days of either carnitine-free or supplemented TPN and at the initiation of enteral nutrition. Additional measurements were performed 4 hours and 24 hours after the acute infusions of carnitine. The rate of protein oxidation and the respiratory quotient were found to be higher, and the rate of fat oxidation to be lower, with carnitine-supplemented TPN, than with either carnitine-free TPN or enteral nutrition. Acute infusion of carnitine resulted in an increased rate of protein oxidation and a reduced rate of fat oxidation on both TPN-regimens. These unfavourable effects on protein metabolism may be due to an impairment of fat oxidation by excess amounts of carnitine.
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We show that the dispersal routes reconstruction problem can be stated as an instance of a graph theoretical problem known as the minimum cost arborescence problem, for which there exist efficient algorithms. Furthermore, we derive some theoretical results, in a simplified setting, on the possible optimal values that can be obtained for this problem. With this, we place the dispersal routes reconstruction problem on solid theoretical grounds, establishing it as a tractable problem that also lends itself to formal mathematical and computational analysis. Finally, we present an insightful example of how this framework can be applied to real data. We propose that our computational method can be used to define the most parsimonious dispersal (or invasion) scenarios, which can then be tested using complementary methods such as genetic analysis.
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This paper analyses and discusses arguments that emerge from a recent discussion about the proper assessment of the evidential value of correspondences observed between the characteristics of a crime stain and those of a sample from a suspect when (i) this latter individual is found as a result of a database search and (ii) remaining database members are excluded as potential sources (because of different analytical characteristics). Using a graphical probability approach (i.e., Bayesian networks), the paper here intends to clarify that there is no need to (i) introduce a correction factor equal to the size of the searched database (i.e., to reduce a likelihood ratio), nor to (ii) adopt a propositional level not directly related to the suspect matching the crime stain (i.e., a proposition of the kind 'some person in (outside) the database is the source of the crime stain' rather than 'the suspect (some other person) is the source of the crime stain'). The present research thus confirms existing literature on the topic that has repeatedly demonstrated that the latter two requirements (i) and (ii) should not be a cause of concern.
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OBJECTIVE: Enteral glutamine supplementation and antioxidants have been shown to be beneficial in some categories of critically ill patients. This study investigated the impact on organ function and clinical outcome of an enteral solution enriched with glutamine and antioxidant micronutrients in patients with trauma and with burns. METHODS: This was a prospective study of a historical control group including critically ill, burned and major trauma patients (n = 86, 40 patients with burns and 46 with trauma, 43 in each group) on admission to an intensive care unit in a university hospital (matching for severity, age, and sex). The intervention aimed to deliver a 500-mL enteral solution containing 30 g of glutamine per day, selenium, zinc, and vitamin E (Gln-AOX) for a maximum of 10 d, in addition to control treatment consisting of enteral nutrition in all patients and intravenous trace elements in all burn patients. RESULTS: Patients were comparable at baseline, except for more inhalation injuries in the burn-Gln-AOX group (P = 0.10) and greater neurologic impairment in the trauma-Gln-AOX group (P = 0.022). Intestinal tolerance was good. The full 500-mL dose was rarely delivered, resulting in a low mean glutamine daily dose (22 g for burn patients and 16 g for trauma patients). In burn patients intravenous trace element delivery was superior to the enteral dose. The evolution of the Sequential Organ Failure Assessment score and other outcome variables did not differ significantly between groups. C-reactive protein decreased faster in the Gln-AOX group. CONCLUSION: The Gln-AOX supplement was well tolerated in critically ill, injured patients, but did not improve outcome significantly. The delivery of glutamine below the 0.5-g/kg recommended dose in association with high intravenous trace element substitution doses in burn patients are likely to have blunted the impact by not reaching an efficient treatment dose. Further trials testing higher doses of Gln are required.