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Risk Period (risk + period)

Distribution by Scientific Domains
Medical Sciences50%
Life Sciences50%

Selected Abstracts

Predation risk allocation or direct vigilance response in the predator interaction between perch (Perca fluviatilis L.) and pike (Esox lucius L.)?

ECOLOGY OF FRESHWATER FISH, Issue 3 2005
A. Vainikka
Abstract , Predation risk allocation hypothesis predicts that a prey's response to predator depends on prey's previous experience on predator. Here we tested whether the group of three perch respond differentially to pike, predator of perch, depending on the timing of high constant (HC) and high unpredictable (HU) risk periods within low constant risk periods in short-term (10 h) experiments, and whether the response is stronger during a HU risk period than during a HC risk period. Perch clearly erected the dorsal fin in response to predation risk treatments (pike odour only, odour and visible pike). Decrease in activity and increase in shoaling behaviour were observed mainly during high risk periods. However, the perch's responses to pike did not differ statistically between periods of various levels of predation risk or depending on the timing of high risk situations within constant low risk periods, and thus, suggesting that perch respond mainly to changes in the current predation risk. Resumen 1. La hipótesis de la asignación de riesgo a la predación predice que la respuesta a un predador depende de la experiencia previa de la presa al predador. En este trabajo analizamos si un grupo de tres individuos de Perca fluviatilis respondían de forma distinta a la presencia de Esox lucius, (un predador común de esta especie) y si éstas dependían del momento en el que se producen periodos de alto riesgo constante y de alto riesgo impredecible, en experimentos de corto plazo (10 horas) de riesgo bajo y constante y si la respuesta era mayor durante perí odos de riesgo impredecible y alto que durante períodos de riesgo constante alto. 2. Claramente P. fluviatilis respondió levantando la aleta dorsal en respuesta a los tratamientos de riesgo a la predación (solamente olor y olor + visibilidad de E. lucius). Una menor actividad y una mayor tendencia a la formación de bancos fueron observados durante períodos de alto riesgo. Sin embargo, las respuesta de P. fluviatilis a E. lucius no difirieron estadísticamente entre períodos de varios niveles de riesgo a la predación o entre aquellos que dependieron del momento en el que se produjeron situaciones de alto riesgo dentro de períodos de bajo riesgo constante. 3. Concluimos que P. fluviatilis puede utilizar señales olfatorias como determinantes de respuestas al riesgo a la predación y responder a aumentos de riesgo, sin excluir la posibilidad de que amenazas repetidas decrezcan la intensidad de la respuesta. Nuestros resultados, obtenidos en experimentos realizados a pequeña escala temporal, no niegan la posibilidad de la P. fluviatilis y otras especies puedan balancear la alimentación con actividades anti-predación, de acuerdo a cambios en el riesgo de predación a lo largo de escalas temporales de varios días. [source]

Survival of Erwinia amylovora on pears and on fruit containers in cold storage and outdoors

EPPO BULLETIN, Issue 1 2004
P. Ceroni
The survival of Erwinia amylovora during cold storage or outdoors may be a relevant factor in the spread of fireblight. The survival of E. amylovora was studied in cold storage on pear fruits, on container materials and on packaging paper, and outdoors on wood (oak and poplar) and on polyethylene. The samples were contaminated with a bacterial suspension of a mutant strain, washed, concentrated by centrifugation, and the final concentrates were used for plate counting. In cold storage, reisolation from the calyx was successful even after 101 days, whereas on pear surfaces, it was unsuccessful after just 1 day. On oak and poplar wood, reisolation was obtained up to 77 days in cold storage for both types of wood, but only up to 27 and 55 days, respectively, outdoors. Reisolation from packaging paper in cold storage was successful up to 14 days. Reisolation from polyethylene outdoors was unsuccessful after 24 h. Survival curves were calculated for each material. On the basis of a model of inoculum transmission, and using the survival curves, a phytosanitary risk period for the different types of materials was estimated. [source]

What are the high risk periods for incident substance use and transitions to abuse and dependence?

INTERNATIONAL JOURNAL OF METHODS IN PSYCHIATRIC RESEARCH, Issue S1 2008
Implications for early intervention, prevention
Abstract Background: For a better understanding of the evolution of addictive disorders and the timely initiation of early intervention and prevention, we have to learn when and how quickly the critical transitions from first substance use (SU) to regular use and from first SU and regular SU to abuse and dependence occur. Little data are currently available on the transitions to substance use disorders (SUDs) across the spectrum of legal and illegal drugs taking into account gender differences. It is the aim of this paper to describe the high density incidence and transition periods of SU and SUD for alcohol, nicotine, cannabis and other illicit drugs for young males and females. Methods: A sample of (N = 3021) community subjects aged 14,24 at baseline were followed-up prospectively over 10-years. SU and SUD were assessed using the DSM-IV/M-CIDI. Results: Ages 10,16 are the high risk period for first alcohol and nicotine use (up to 38% of subjects start before age 14). Onset of illegal SU occurs later. Substantial proportions of transitions to regular SU and SUD occur in the first three years after SU onset. Only few gender differences were found for time patterns of SU/SUD incidence and transition. Conclusion: Except for alcohol the time windows for targeted intervention to prevent progression to malignant patterns in adolescence are critically small, leaving little time for targeted intervention to prevent transition. The fast transitions to abuse and dependence in adolescence may be indicative for the increased vulnerability to substance effects in this time period. Basic research on the determinants of transitions should thus target this period in adolescence. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Case-crossover study of hospitalization for acute hepatitis in Chinese herb users

JOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 10 2008
Chang-Hsing Lee
Abstract Background and Aim:, Despite the increase in popularity of herbal products, there is growing concern over potential health hazards caused by the Chinese herbal medicines (CHMs) that are regularly reimbursed under the National Health Insurance system in Taiwan. This study attempts to determine the association between CHM prescriptions and acute hepatitis,related hospitalizations. Methods:, A case-crossover study was designed on 200 000 randomly selected individuals from the National Health Insurance Research Database who were then followed from 1997 to 2002. All medications taken in the 30- and 60-day periods prior to hospitalization were explored and compared with four control periods (the 180- and 360-day periods prior to and after the hospitalization). A conditional logistic regression model was then constructed to determine the odds of CHM being prescribed during these risk periods. Results:, There were a total of 12 cases with nonviral, nonalcoholic hepatitis patients who took CHM prescriptions during the 30-day risk or control periods. After adjustment for conventional hepatotoxic drugs, the odds ratio during the 30-day risk period was 3.4 (95% confidence interval [CI]: 1.1, 9.8) for nonviral, nonalcoholic acute hepatitis. A detailed historical review of CHMs for each patient revealed that the odds ratio increased to 4.2 for those prescribed formulae containing Radix Paeoniae (95% CI: 1.1, 15.7) and Radix Glycyrrhizae (95% CI: 1.2, 15.2). Conclusions:, Chinese herbal users revealed a slightly increased risk of acute hepatitis. We therefore recommend pharmacovigilance and active surveillance for CHMs suspected with hepatotoxicity. [source]

Predation risk allocation or direct vigilance response in the predator interaction between perch (Perca fluviatilis L.) and pike (Esox lucius L.)?

ECOLOGY OF FRESHWATER FISH, Issue 3 2005
A. Vainikka
Abstract , Predation risk allocation hypothesis predicts that a prey's response to predator depends on prey's previous experience on predator. Here we tested whether the group of three perch respond differentially to pike, predator of perch, depending on the timing of high constant (HC) and high unpredictable (HU) risk periods within low constant risk periods in short-term (10 h) experiments, and whether the response is stronger during a HU risk period than during a HC risk period. Perch clearly erected the dorsal fin in response to predation risk treatments (pike odour only, odour and visible pike). Decrease in activity and increase in shoaling behaviour were observed mainly during high risk periods. However, the perch's responses to pike did not differ statistically between periods of various levels of predation risk or depending on the timing of high risk situations within constant low risk periods, and thus, suggesting that perch respond mainly to changes in the current predation risk. Resumen 1. La hipótesis de la asignación de riesgo a la predación predice que la respuesta a un predador depende de la experiencia previa de la presa al predador. En este trabajo analizamos si un grupo de tres individuos de Perca fluviatilis respondían de forma distinta a la presencia de Esox lucius, (un predador común de esta especie) y si éstas dependían del momento en el que se producen periodos de alto riesgo constante y de alto riesgo impredecible, en experimentos de corto plazo (10 horas) de riesgo bajo y constante y si la respuesta era mayor durante perí odos de riesgo impredecible y alto que durante períodos de riesgo constante alto. 2. Claramente P. fluviatilis respondió levantando la aleta dorsal en respuesta a los tratamientos de riesgo a la predación (solamente olor y olor + visibilidad de E. lucius). Una menor actividad y una mayor tendencia a la formación de bancos fueron observados durante períodos de alto riesgo. Sin embargo, las respuesta de P. fluviatilis a E. lucius no difirieron estadísticamente entre períodos de varios niveles de riesgo a la predación o entre aquellos que dependieron del momento en el que se produjeron situaciones de alto riesgo dentro de períodos de bajo riesgo constante. 3. Concluimos que P. fluviatilis puede utilizar señales olfatorias como determinantes de respuestas al riesgo a la predación y responder a aumentos de riesgo, sin excluir la posibilidad de que amenazas repetidas decrezcan la intensidad de la respuesta. Nuestros resultados, obtenidos en experimentos realizados a pequeña escala temporal, no niegan la posibilidad de la P. fluviatilis y otras especies puedan balancear la alimentación con actividades anti-predación, de acuerdo a cambios en el riesgo de predación a lo largo de escalas temporales de varios días. [source]

What are the high risk periods for incident substance use and transitions to abuse and dependence?

INTERNATIONAL JOURNAL OF METHODS IN PSYCHIATRIC RESEARCH, Issue S1 2008
Implications for early intervention, prevention
Abstract Background: For a better understanding of the evolution of addictive disorders and the timely initiation of early intervention and prevention, we have to learn when and how quickly the critical transitions from first substance use (SU) to regular use and from first SU and regular SU to abuse and dependence occur. Little data are currently available on the transitions to substance use disorders (SUDs) across the spectrum of legal and illegal drugs taking into account gender differences. It is the aim of this paper to describe the high density incidence and transition periods of SU and SUD for alcohol, nicotine, cannabis and other illicit drugs for young males and females. Methods: A sample of (N = 3021) community subjects aged 14,24 at baseline were followed-up prospectively over 10-years. SU and SUD were assessed using the DSM-IV/M-CIDI. Results: Ages 10,16 are the high risk period for first alcohol and nicotine use (up to 38% of subjects start before age 14). Onset of illegal SU occurs later. Substantial proportions of transitions to regular SU and SUD occur in the first three years after SU onset. Only few gender differences were found for time patterns of SU/SUD incidence and transition. Conclusion: Except for alcohol the time windows for targeted intervention to prevent progression to malignant patterns in adolescence are critically small, leaving little time for targeted intervention to prevent transition. The fast transitions to abuse and dependence in adolescence may be indicative for the increased vulnerability to substance effects in this time period. Basic research on the determinants of transitions should thus target this period in adolescence. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Case-crossover study of hospitalization for acute hepatitis in Chinese herb users

JOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 10 2008
Chang-Hsing Lee
Abstract Background and Aim:, Despite the increase in popularity of herbal products, there is growing concern over potential health hazards caused by the Chinese herbal medicines (CHMs) that are regularly reimbursed under the National Health Insurance system in Taiwan. This study attempts to determine the association between CHM prescriptions and acute hepatitis,related hospitalizations. Methods:, A case-crossover study was designed on 200 000 randomly selected individuals from the National Health Insurance Research Database who were then followed from 1997 to 2002. All medications taken in the 30- and 60-day periods prior to hospitalization were explored and compared with four control periods (the 180- and 360-day periods prior to and after the hospitalization). A conditional logistic regression model was then constructed to determine the odds of CHM being prescribed during these risk periods. Results:, There were a total of 12 cases with nonviral, nonalcoholic hepatitis patients who took CHM prescriptions during the 30-day risk or control periods. After adjustment for conventional hepatotoxic drugs, the odds ratio during the 30-day risk period was 3.4 (95% confidence interval [CI]: 1.1, 9.8) for nonviral, nonalcoholic acute hepatitis. A detailed historical review of CHMs for each patient revealed that the odds ratio increased to 4.2 for those prescribed formulae containing Radix Paeoniae (95% CI: 1.1, 15.7) and Radix Glycyrrhizae (95% CI: 1.2, 15.2). Conclusions:, Chinese herbal users revealed a slightly increased risk of acute hepatitis. We therefore recommend pharmacovigilance and active surveillance for CHMs suspected with hepatotoxicity. [source]