scholarly journals EARTHQUAKE FORECAST BY TIME-DEPENDENT HAZARD MODELS

2017 ◽  
Vol 50 (3) ◽  
pp. 1309
Author(s):  
R. Console
Keyword(s):  
Epidemic Model ◽  
Stress Change ◽  
Time Dependent ◽  
Occurrence Rate ◽  
Hazard Models ◽  
Short Term ◽  
Probability Of Occurrence ◽  
Seismogenic Structures ◽  
Definition Of

This presentation outlines methodological aspects of earthquake forecasting. The recurring debates concerning predictability of earthquakes clearly show how this problem is centred on the difficulty of systematically testing the numerous methodologies that in the years have been proposed and sustained by the supporters of prediction. This difficulty starts, sometimes, from the lack of a quantitative and rigorous definition of the concerned precursor, and other times from the lack of continuous observations, upon which statistical analyses could be based. After an introduction concerning the definition of earthquake precursors, the way how to validate forecast hypotheses and the cost associated to their operational application, I give two examples of time-dependent hazard models, for long-term and short-term earthquake forecasts respectively. Considering the long-term forecast modelling, the effect of stress change due to previous historical earthquakes on the probability of occurrence of future earthquakes on neighbouring faults is taken into account. Following a standard methodology developed a couple of decades ago, the probability of occurrence in the next 50 years for a characteristic earthquake on known seismogenic structures can be estimated by a time-dependent renewal model. Then, a physical model for the Coulomb stress change caused by previous earthquakes on these structures is applied. The influence of this stress change on the occurrence rate of characteristic earthquakes is computed taking into account the permanent perturbation (clock advance). The method so developed is applied to the computation of earthquake hazard of the main seismogenic structures recognized in the Southern Apennines region, for which both historical and paleoseismological data are available. A popular short-term time dependent hazard forecast model is the epidemic model. In this model earthquakes are regarded as the realization of a stochastic point process, and their magnitude distribution is described by the Gutenberg-Richter law with a constant b-value. The occurrence rate density is computed by the sum of two terms, one representing the independent, or spontaneous activity, and the other representing the activity induced by previous earthquakes. While the first term depends only on space, the second one is factored into three terms that respectively include the magnitude, time and location of the past earthquakes. An example of application of the epidemic model to the 2009 L’Aquila seismic series is shown.

Selected Contribution: Chronic intermittent hypoxia enhances respiratory long-term facilitation in geriatric female rats

2003 ◽  
Vol 95 (6) ◽  
pp. 2614-2623 ◽  
Author(s):  
A. G. Zabka ◽  
G. S. Mitchell ◽  
E. B. Olson ◽  
M. Behan
Keyword(s):  
Intermittent Hypoxia ◽  
Young Female ◽  
Time Dependent ◽  
Female Rats ◽  
Chronic Intermittent Hypoxia ◽  
Middle Aged ◽  
Short Term ◽  
Hypoxic Response ◽  
Long Term Facilitation

Age and the estrus cycle affect time-dependent respiratory responses to episodic hypoxia in female rats. Respiratory long-term facilitation (LTF) is enhanced in middle-aged vs. young female rats ( 72 ). We tested the hypothesis that phrenic and hypoglossal (XII) LTF are diminished in acyclic geriatric rats when fluctuating sex hormone levels no longer establish conditions that enhance LTF. Chronic intermittent hypoxia (CIH) enhances LTF ( 41 ); thus we further predicted that CIH would restore LTF in geriatric female rats. LTF was measured in young (3-4 mo) and geriatric (20-22 mo) female Sasco Sprague-Dawley rats and in a group of geriatric rats exposed to 1 wk of nocturnal CIH (11 vs. 21% O2 at 5-min intervals, 12 h/night). In anesthetized, paralyzed, vagotomized, and ventilated rats, time-dependent hypoxic phrenic and XII responses were assessed. The short-term hypoxic response was measured during the first of three 5-min episodes of isocapnic hypoxia (arterial Po2 35-45 Torr). LTF was assessed 15, 30, and 60 min postepisodic hypoxia. Phrenic and XII short-term hypoxic response was not different among groups, regardless of CIH treatment ( P > 0.05). LTF in geriatric female rats was smaller than previously reported for middle-aged rats but comparable to that in young female rats. CIH augmented phrenic and XII LTF to levels similar to those of middle-aged female rats without CIH ( P < 0.05). The magnitude of phrenic and XII LTF in all groups was inversely related to the ratio of progesterone to estradiol serum levels ( P < 0.05). Thus CIH and sex hormones influence the magnitude of LTF in geriatric female rats.

scholarly journals When is a Learning Object not an Object: A first step towards a theory of learning objects

2002 ◽  
Vol 3 (2) ◽  
Author(s):  
Mike Sosteric ◽  
Susan Hesemeier
Keyword(s):  
Economies Of Scale ◽  
Learning Objects ◽  
Short Term ◽  
Object A ◽  
Smart Learning ◽  
Smart Learning Environments ◽  
Adequate Definition ◽  
Definition Of ◽  
Conceptual Confusion

<p> For some, “learning objects" are the “next big thing” in distance education promising smart learning environments, fantastic economies of scale, and the power to tap into expanding educational markets. While learning objects may be revolutionary in the long term, in the short term, definitional problems and conceptual confusion undermine our ability to understand and critically evaluate the emerging field. This article is an attempt to provide an adequate definition of learning objects by (a) jettisoning useless theoretical links hitherto invoked to theorize learning objects, and (b) reducing the definition of learning objects to the bare essentials. The article closes with suggestions for further research and further refinement of the definition of learning objects. </P>

scholarly journals Systema Temporis: A Time-Based Dimensional Framework for Consciousness and Cognition

2019 ◽  
Author(s):  
Lachlan Kent ◽  
George Van Doorn ◽  
Britt Klein
Keyword(s):  
Time Perception ◽  
Dimensional Structure ◽  
Two Dimensional ◽  
Dimensional Approach ◽  
Short Term ◽  
Hierarchical Framework ◽  
Time Consciousness ◽  
Emotion And Memory ◽  
Definition Of

This study uses a combined categorical-dimensional approach to depict a hierarchical framework for consciousness similar to, and contiguous with, factorial models of cognition (cf., intelligence). On the basis of the longstanding definition of time consciousness, the analysis employs a dimension of temporal extension, in the same manner that psychology has temporally organised memory (i.e., short-term, long-term, and long-lasting memories). By defining temporal extension in terms of the structure of time perception at short timescales (&lt; 100 s), memory and time consciousness are proposed to fit along the same logarithmic dimension. This suggests that different forms of time consciousness (e.g., experience, wakefulness, and self-consciousness) are embedded within, or supported by, the ascending timescales of different modes of memory (i.e., short-term, long-term, etc.). A secondary dimension is also proposed to integrate higher-order forms of consciousness/emotion and memory/cognition. The resulting two-dimensional structure accords with existing theories of cognitive and emotional intelligence.

Glucocorticoids Decrease the Conversion of Thyroxine into 3,5,3′-Tri-Iodothyronine by Isolated Rat Renal Tubules

1982 ◽  
Vol 62 (2) ◽  
pp. 215-220 ◽  
Author(s):  
P. Heyma ◽  
R. G. Larkins
Keyword(s):  
Strong Evidence ◽  
Glucocorticoid Receptors ◽  
Actinomycin D ◽  
Time Dependent ◽  
Renal Tubules ◽  
Short Term ◽  
Collagenase Digestion ◽  
Isolated Rat

1. The effect of glucocorticoids on the deiodination of thyroxine (T4) to 3,5,3′-tri-iodothyronine (T3) was studied in rat renal tubules prepared by collagenase digestion. 2. In short-term (6 h) experiments, cortisol and dexamethasone inhibited the conversion of T4 into T3 at concentrations of 2 × 10-4 mol/l and 2 × 10-5 mol/l respectively. The inhibition by cortisol and dexamethasone was time dependent and was prevented by actinomycin D and progesterone, suggesting that the inhibition is mediated by an effect on nuclear transcription dependent on binding to glucocorticoid receptors. 3. In long-term (16 h) experiments, cortisol and dexamethasone inhibited T4 to T3 conversion by the tubules at concentrations of 1 × 10-12 mol/l and above. In addition, physiological concentrations of corticosterone (1 × 10-8 mol/l) were able to decrease T3 generation from T4. 4. Our data provide strong evidence that physiological concentrations of glucocorticoids are able to affect T3 production from T4 directly and suggest that they may be important regulators of T4 deiodination.

Seasonal to multi-annual speedup and slowdown of Greenland outlet glaciers inferred from time-dependent remote sensing observations

2020 ◽  
Author(s):  
Lizz Ultee ◽  
Bryan Riel ◽  
Brent Minchew
Keyword(s):  
Time Series ◽  
Flow Velocity ◽  
Ice Sheet ◽  
Surface Air Temperature ◽  
Greenland Ice Sheet ◽  
Time Dependent ◽  
Surface Velocity ◽  
Short Term ◽  
Ice Flow

&lt;p&gt;The rate of ice flux from the Greenland Ice Sheet to the ocean depends on the ice flow velocity through outlet glaciers. Ice flow velocity, in turn, evolves in response to multiple geographic and environmental forcings at different timescales. For example, velocity may vary daily in response to ocean tides, seasonally in response to surface air temperature, and multi-annually in response to long-term trends in climate. The satellite observations processed as part of the NASA MEaSUREs Greenland Ice Sheet Velocity Map allow us to analyse variations in ice surface velocity at multiple timescales. Here, we decompose short-term and long-term signals in time-dependent velocity fields for Greenland outlet glaciers based on the methods of Riel et al. (2018). Patterns found in short-term signals can constrain basal sliding relations and ice rheology, while the longer-term signals hint at decadal in/stability of outlet glaciers. We present example velocity time series for outlets including Sermeq Kujalleq (Jakobshavn Isbrae) and Helheim Glacier, and we highlight features indicative of dynamic drawdown or advective restabilization. Finally, we comment on the capabilities of a time series analysis software under development for glaciological applications.&lt;/p&gt;

Drinking problems among recidivist prisoners

1971 ◽  
Vol 1 (5) ◽  
pp. 388-399 ◽  
Author(s):  
Griffith Edwards ◽  
Celia Hensman ◽  
Julian Peto
Keyword(s):  
Operant Conditioning ◽  
Prison Population ◽  
Short Term ◽  
Social Instability ◽  
Drinking Problems ◽  
Homeless Men ◽  
Conditioning Model ◽  
Methodological Problems ◽  
Definition Of

SYNOPSISThe general relationship between alcohol and crime is reviewed, and five central methodological problems are identified relevant to prison population ‘alcoholism prevalence surveys’ as a prelude to a report of an investigation of 500 recidivist prisoners. The prevalence rate is shown to be highly dependent on the particular definition of ‘alcoholism’ which is employed. Long-term and short-term prisoner subgroups are compared, and similarities with a population of non-prisoner homeless men discussed. A ‘dependence score’ derived from an operant conditioning model of alcoholism correlates significantly with various measures of social instability.

Association of adrenal hormone metabolites and mortality over a 6-year follow-up in COPD patients with acute exacerbation

2018 ◽  
Vol 56 (4) ◽  
pp. 669-680 ◽  
Author(s):  
Seline Zurfluh ◽  
Manuela Nickler ◽  
Manuel Ottiger ◽  
Christian Steuer ◽  
Alexander Kutz ◽  
...  
Keyword(s):  
Cox Regression ◽  
Time Dependent ◽  
Chronic Obstructive ◽  
Short Term ◽  
Therapeutic Implications ◽  
Adrenal Hormone ◽  
Copd Patients ◽  
Short And Long Term ◽  
Long Term Mortality

Abstract Background: The release of hormones from the adrenal gland is vital in acute and chronic illnesses such as chronic obstructive pulmonary disease (COPD) involving recurrent exacerbations. Using a metabolomic approach, we aim to investigate associations of different adrenal hormone metabolites with short- and long-term mortality in COPD patients. Methods: We prospectively followed 172 COPD patients (median age 75 years, 62% male) from a previous Swiss multicenter trial. At baseline, we measured levels of a comprehensive spectrum of adrenal hormone metabolites, including glucocorticoid, mineralocorticoid and androgen hormones by liquid chromatography coupled with tandem mass spectrometry (MS). We calculated Cox regression models adjusted for gender, age, comorbidities and previous corticosteroid therapy. Results: Mortality was 6.4% after 30 days and increased to 61.6% after 6 years. Higher initial androgen hormones predicted lower long-term mortality with significant results for dehydroepiandrosterone (DHEA) [adjusted hazard ratio (HR), 0.82; 95% confidence interval (CI), 0.70–0.98; p=0.026] and dehydroepiandrosterone sulfate (DHEA-S) (adjusted HR, 0.68; 95% CI, 0.50–0.91; p=0.009). An activation of stress hormones (particularly cortisol and cortisone) showed a time-dependent effect with higher levels pointing towards higher mortality at short term, but lower mortality at long term. Activation of the mineralocorticoid axis tended to be associated with increased short-term mortality (adjusted HR of aldosterone, 2.76; 95% CI, 0.79–9.65; p=0.111). Conclusions: Independent of age, gender, corticosteroid exposure and exacerbation type, adrenal hormones are associated with mortality at short and long term in patients with COPD exacerbation with different time-dependent effects of glucocorticoids, androgens and mineralocorticoids. A better physiopathological understanding of the causality of these effects may have therapeutic implications.

scholarly journals Zaniedbane emocjonalnie dzieci – symptomy, diagnoza, formy wsparcia w środowisku przedszkolnym

2020 ◽  
Vol 25 (3) ◽  
pp. 33-44
Author(s):  
Angelika Kleszczewska-Albińska
Keyword(s):  
Diagnostic Procedures ◽  
Kindergarten Teachers ◽  
Emotional Neglect ◽  
Short Term ◽  
Behavioral Techniques ◽  
Long Term Consequences ◽  
Neglected Children ◽  
Definition Of

Children Emotional Neglect – Symptoms, Diagnosis, Forms of Support in Kindergarten Environment This article aims to present analysis of possible actions of kindergarten teachers and other specialists working with emotionally neglected children. The first part of the text includes definition of emotional neglect and information about the symptoms observed in emotionally neglected child. The short term and long term consequences of emotional neglect in group of children aged 3–6 were shortly described. The characteristics enabling recognition of emotional neglect and diagnostic procedures facilitating identification of a problem by teachers and kindergarten specialists were given. Basic cues concerning the work with emotionally neglected child that can be accomplished in kindergarten, including description of basic behavioral techniques, were presented. The cues for working with neglecting parent were also given. The article serves as a preliminary set of indicators for working with emotionally neglected children.

Splenectomy in Patients with Myeloproliferative Neoplasms (MPNs): Efficacy, Complications and Impact On Survival and Transformation.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2853-2853
Author(s):  
Fabio P S Santos ◽  
Constantine S. Tam ◽  
Hagop M. Kantarjian ◽  
Jorge E. Cortes ◽  
Deborah A. Thomas ◽  
...  
Keyword(s):  
Myeloproliferative Neoplasms ◽  
Therapeutic Option ◽  
Splenic Vein ◽  
Time Dependent ◽  
Chromosome 17 ◽  
Short Term ◽  
Post Surgery ◽  
Impact On Survival ◽  
Md Anderson

Abstract Abstract 2853 Introduction: Splenectomy may be an effective therapeutic option for treating massive splenomegaly in patients with MPNs. There is still limited data on its short- and long-term benefits and risks. Objective: To describe short-term outcomes, complications and impact on survival and transformation to acute myeloid leukemia (AML) in patients with MPNs who underwent splenectomy. Methods: First, efficacy and short-term complications were analyzed in 94 patients with different MPNs who underwent splenectomy at MD Anderson between 1981–2009. Second, medical records of 696 patients with myelofibrosis (MF) seen at MD Anderson between 1966–2009 were reviewed (among which 91 underwent splenectomy either at or outside MD Anderson) to evaluate the long-term impact of splenectomy on overall survival (OS) and transformation-free survival (TFS). Improvement in anemia and thrombocytopenia were defined by the International Working Group on Myelofibrosis Research and Treatment response criteria. Survival was estimated by Kaplan-Meier method, and hazard ratios (HR) were determined by Cox multivariate analysis. Splenectomy was analyzed as a time-dependent covariate. Risk in patients with MF was determined by the Dynamic International Prognostic Scoring System (DIPSS). Accelerated phase (AP) criteria in MF were determined as thrombocytopenia <50×109/L, chromosome 17 abnormalities and blasts >10% in peripheral blood (PB) or bone marrow (BM). Results: Splenectomy improved spleen pain, anemia and thrombocytopenia in 84%, 47% and 66% of patients, respectively. Among patients with MF, improvement in anemia and thrombocytopenia was seen in 44% and 75% of patients, respectively. Hematological complications included post-operative leukocytosis (76%) and thrombocytosis (43%), developing within a median time of 1 day and 5 days post-surgery, respectively. Early (<7 days) intervention for control of elevated white blood cell and/or platelet count was needed in 37% of patients. Forty-six percent of patients developed non-hematological clinical complications, and the most common was venous thromboembolism (VTE; 16%). VTE sites included portal vein (N=11), supra-hepatic vein (N=3) and superior vena cava, pulmonary embolism and splenic vein (N=1 each). Post-operative mortality was 5%. Median survival post-splenectomy was 19.2 months, and 5-year survival 16.1%. In the second cohort of patients with MF, requirement for splenectomy was associated with decreased OS (HR=2.84, p<0.0001) and TFS (HR=2.79, p<0.0001). In the multivariable model, the time dependent covariate splenectomyremained an independent risk factor for inferior OS and TFS in patients with MF, alongside male sex, transfusion dependency, DIPSS score and AP criteria (Table). Conclusions: Splenectomyis a possible therapeutic option for patients with MF and other MPNs, and its greatest benefits are related to improvement in spleen pain and discomfort, anemia and thrombocytopenia. However, in patients with MF it appears to be associated with increased mortality and risk of transformation to AML. Disclosures: No relevant conflicts of interest to declare.

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