On GARCH(p,q) convergence

The paper deals with symmetric GARCH(p,q) model. Assuming that there exists defined by this model stationary time series, we have proposed the necessary and sufficient condition for exponential mean square convergence of any stochastic recurrent procedure satisfying this model to the above stationary time series. A mathematical background of the proposal approach is based on the derived covariance method for mean square exponential stability analysis of linear stochastic difference equations, which permits one to state a mean square convergence criterion for GARCH(p,q) models with any integer positive p and q in the convenient for application form of an integral inequality involving the model parameters.Рассматривается симметричная модель GARCH(p,q). В предположении, что существует задаваемый этой моделью стационарный временной ряд, предлагается необходимое и достаточное условие сходимости в среднем квадратичном любой итерационной процедуры, удовлетворяющей уравнению GARCH(p,q), к этому стационарному процессу. Предложен ковариационный метод анализа линейных разностных уравнений со случайными коэффициентами, который позволил для произвольных целых неотрицательных p и q сформулировать критерий сходимости в среднем квадратичном в удобной для использования форме в виде интегрального неравенства, содержащего параметры модели.Розглядається симетрична модель GARCH(p,q). Припускаючи існування стаціонарного часового ряду, який задається цією моделлю, пропонується необхідна і достатня умова збіжності у середньому квадратичному будь-якої ітераційної процедури, що задовольняє рівнянню GARCH(p,q), до такого стаціонарного процесу. Запропоновано коваріаційний метод аналізу лінійних різницевих рівнянь із випадковими коефіцієнтами, що уможливило для довільних цілих невід’ємних p и q сформулювати критерій збіжності у середньому квадратичному в зручній для використання формі у вигляді інтегральної нерівності із параметрами моделі

Avaliação agronômica sob pastejo de Andropogon gayanus cv. Planaltina consorciado com Desmodium ovalifolium.

O presente trabalho teve por objetivo avaliar os efeitos das taxas de lotação (1,0; 1,5; 2,0 e 2,5 UA/ha (UA = 450 kg de peso vivo), em uma pastagem consorciada de Andropogon gayanus e Desmodium ovalifolium CIAT-350, cultivada em Porto Velho, Rondônia. Cada tratamento teve um número fixo de animais (três/piquete), variando-se o tamanho da área em função da carga animal. Foram utilizados garrotes Holando-Zebu, com peso médio inicial de 120 a 150 kg. A gramínea e a leguminosa foram plantadas em linhas alternadas espaçadas de 0,5 m. A densidade de semeadura foi de 10 e 2 kg/ha, respectivamente para A. gayanus cv. Planaltina e D. ovalifolium CIAT-350. A adubação de estabelecimento constou da aplicação de 50 kg de P2O5/ha, sob a forma de superfosfato triplo. O sistema de pastejo foi rotativo com 7 dias de ocupação por 21 dias de descanso. O aumento da carga animal reduziu significativamente a disponibilidade total de forragem, ocorrendo o inverso quanto aos teores de PB. A percentagem de leguminosa na pastagem foi diretamente proporcional à carga animal. Considerando-se a disponibilidade e qualidade da forragem e a composição botânica da pastagem, recomenda-se a utilização de 1,5 e 1,0 UA/ha, respectivamente para os períodos chuvoso e seco

Quantitative gait analysis under dual-task in older people with mild cognitive impairment: a reliability study

<p>Abstract</p> <p>Background</p> <p>Reliability of quantitative gait assessment while dual-tasking (walking while doing a secondary task such as talking) in people with cognitive impairment is unknown. Dual-tasking gait assessment is becoming highly important for mobility research with older adults since better reflects their performance in the basic activities of daily living. Our purpose was to establish the test-retest reliability of assessing quantitative gait variables using an electronic walkway in older adults with mild cognitive impairment (MCI) under single and dual-task conditions.</p> <p>Methods</p> <p>The gait performance of 11 elderly individuals with MCI was evaluated using an electronic walkway (GAITRite^®System) in two sessions, one week apart. Six gait parameters (gait velocity, step length, stride length, step time, stride time, and double support time) were assessed under two conditions: single-task (sG: usual walking) and dual-task (dG: counting backwards from 100 while walking). Test-retest reliability was determined using intra-class correlation coefficient (ICC). Gait variability was measured using coefficient of variation (CoV).</p> <p>Results</p> <p>Eleven participants (average age = 76.6 years, SD = 7.3) were assessed. They were high functioning (Clinical Dementia Rating Score = 0.5) with a mean Mini-Mental Status Exam (MMSE) score of 28 (SD = 1.56), and a mean Montreal Cognitive Assessment (MoCA) score of 22.8 (SD = 1.23). Under dual-task conditions, mean gait velocity (GV) decreased significantly (sGV = 119.11 ± 20.20 cm/s; dGV = 110.88 ± 19.76 cm/s; p = 0.005). Additionally, under dual-task conditions, higher gait variability was found on stride time, step time, and double support time. Test-retest reliability was high (ICC>0.85) for the six parameters evaluated under both conditions.</p> <p>Conclusion</p> <p>In older people with MCI, variability of time-related gait parameters increased with dual-tasking suggesting cognitive control of gait performance. Assessment of quantitative gait variables using an electronic walkway is highly reliable under single and dual-task conditions. The presence of cognitive impairment did not preclude performance of dual-tasking in our sample supporting that this methodology can be reliably used in cognitive impaired older individuals.</p

Factors influencing identification of and response to intimate partner violence: a survey of physicians and nurses

BACKGROUND: Intimate partner violence against women (IPV) has been identified as a serious public health problem. Although the health care system is an important site for identification and intervention, there have been challenges in determining how health care professionals can best address this issue in practice. We surveyed nurses and physicians in 2004 regarding their attitudes and behaviours with respect to IPV, including whether they routinely inquire about IPV, as well as potentially relevant barriers, facilitators, experiential, and practice-related factors. METHODS: A modified Dillman Tailored Design approach was used to survey 1000 nurses and 1000 physicians by mail in Ontario, Canada. Respondents were randomly selected from professional directories and represented practice areas pre-identified from the literature as those most likely to care for women at the point of initial IPV disclosure: family practice, obstetrics and gynecology, emergency care, maternal/newborn care, and public health. The survey instrument had a case-based scenario followed by 43 questions asking about behaviours and resources specific to woman abuse. RESULTS: In total, 931 questionnaires were returned; 597 by nurses (59.7% response rate) and 328 by physicians (32.8% response rate). Overall, 32% of nurses and 42% of physicians reported routinely initiating the topic of IPV in practice. Principal components analysis identified eight constructs related to whether routine inquiry was conducted: preparedness, self-confidence, professional supports, abuse inquiry, practitioner consequences of asking, comfort following disclosure, practitioner lack of control, and practice pressures. Each construct was analyzed according to a number of related issues, including clinician training and experience with woman abuse, area of practice, and type of health care provider. Preparedness emerged as a key construct related to whether respondents routinely initiated the topic of IPV. CONCLUSION: The present study provides new insight into the factors that facilitate and impede clinicians' decisions to address the issue of IPV with their female patients. Inadequate preparation, both educational and experiential, emerged as a key barrier to routine inquiry, as did the importance of the "real world" pressures associated with the daily context of primary care practice

Cloning and endogenous expression of a Eucalyptus grandis UDP-glucose dehydrogenase cDNA

UDP-glucose dehydrogenase (UGDH) catalyzes the oxidation of UDP-glucose (UDP-Glc) to UDP-glucuronate (UDP-GlcA), a key sugar nucleotide involved in the biosynthesis of plant cell wall polysaccharides. A full-length cDNA fragment coding for UGDH was cloned from the cambial region of 6-month-old E. grandis saplings by RT-PCR. The 1443-bp-ORF encodes a protein of 480 amino acids with a predicted molecular weight of 53 kDa. The recombinant protein expressed in Escherichia coli catalyzed the conversion of UDP-Glc to UDP-GlcA, confirming that the cloned cDNA encodes UGDH. The deduced amino acid sequence of the cDNA showed a high degree of identity with UGDH from several plant species. The Southern blot assay indicated that more than one copy of UGDH is present in Eucalyptus. These results were also confirmed by the proteomic analysis of the cambial region of 3- and 22-year-old E. grandis trees by 2-DE and LC-MS/MS, showing that at least two isoforms are present. The cloned gene is mainly expressed in roots, stem and bark of 6-month-old saplings, with a lower expression in leaves. High expression levels were also observed in the cambial region of 3- and 22-year-old trees. The results described in this paper provide a further view of the hemicellulose biosynthesis during wood formation in E. grandis

Is there value in using physician billing claims along with other administrative health care data to document the burden of adolescent injury? An exploratory investigation with comparison to self-reports in Ontario, Canada

BACKGROUND: Administrative health care databases may be particularly useful for injury surveillance, given that they are population-based, readily available, and relatively complete. Surveillance based on administrative data, though, is often restricted to injuries that result in hospitalization. Adding physician billing data to administrative data-based surveillance efforts may improve comprehensiveness, but the feasibility of such an approach has rarely been examined. It is also not clear how injury surveillance information obtained using administrative health care databases compares with that obtained using self-report surveys. This study explored the value of using physician billing data along with hospitalization data for the surveillance of adolescent injuries in Ontario, Canada. We aimed i) to document the burden of adolescent injury using administrative health care data, focusing on the relative contribution of physician billing information; and ii) to explore data quality issues by directly comparing adolescent injuries identified in administrative and self-report data. METHODS: The sample included adolescents aged 12 to 19 years who participated in the 1996–1997 cross-sectional Ontario Health Survey, and whose survey responses were linked to administrative health care datasets (N = 2067). Descriptive analysis was used to document the burden of injuries as a proportion of all physician care by gender and location of care, and to examine the distribution of both administratively-defined and self-reported activity-limiting injuries according to demographic characteristics. Administratively-defined and self-reported injuries were also directly compared at the individual level. RESULTS: Approximately 10% of physician care for the sample was identified as injury-related. While 18.8% of adolescents had self-reported injury in the previous year, 25.0% had documented administratively-defined injury. The distribution of injuries according to demographic characteristics was similar across data sources, but congruence was low at the individual level. Possible reasons for discrepancies between the data sources included recall errors in the survey data and errors in the physician billing data algorithm. CONCLUSION: If further validated, physician billing data could be used along with hospital inpatient data to make an important and unique contribution to adolescent injury surveillance. The limitations inherent in different datasets highlight the need to continue rely on multiple information sources for complete injury surveillance information

Socioeconomic status and non-fatal injuries among Canadian adolescents: variations across SES and injury measures

BACKGROUND: While research to date has consistently demonstrated that socioeconomic status (SES) is inversely associated with injury mortality in both children and adults, findings have been less consistent for non-fatal injuries. The literature addressing SES and injury morbidity among adolescents has been particularly inconclusive. To explore potential explanations for these discrepant research findings, this study uniquely compared the relationship across different measures of SES and different causes of injury (recreation versus non-recreation injuries) within a sample of Canadian adolescents. METHODS: The sample included adolescent participants (aged 12 to 19 years) in the Canadian 1996–1997 cross-sectional National Population Health Survey (n = 6967). Five SES measures (household income, two neighbourhood-level proxy measures, two parental indicators) were examined in relation to three injury outcomes (total, recreation, and non-recreation injuries) using multivariable logistic regression. RESULTS: Among males, a clear relationship with injury was observed only for a parental SES index, which was positively associated with total and recreation injuries (odds ratios for the highest versus lowest SES category of 1.9 for total and 2.5 for recreation injuries). Among females, there was some evidence of a positive relationship between SES and injuries, particularly for a neighbourhood-level education measure with total and recreation injuries (odds ratios of 1.7 for total and 2.0 for recreation injuries). CONCLUSION: The results suggest that differences related to the measures of SES chosen and the causes of injury under study may both contribute to discrepancies in past research on SES and non-fatal injuries among adolescents. To clarify the potential SES-injury relationship among youth, the findings emphasize a need for a greater understanding of the meaning and relevance of different SES measures for adolescents, and for an exploration of the pathways through which SES may be related to injury risk

Are clinicians being prepared to care for abused women? A survey of health professional education in Ontario, Canada

Background: The current project undertook a province-wide survey and environmental scan of educational opportunities available to future health care providers on the topic of intimate partner violence (IPV) against women. Methods: A team of experts identified university and college programs in Ontario, Canada as potential providers of IPV education to students in health care professions at the undergraduate and post-graduate levels. A telephone survey with contacts representing these programs was conducted between October 2005 and March 2006. The survey asked whether IPV-specific education was provided to learners, and if so, how and by whom. Results: In total, 222 eligible programs in dentistry, medicine, nursing and other allied health professions were surveyed, and 95% (212/222) of programs responded. Of these, 57% reported offering some form of IPV-specific education, with undergraduate nursing (83%) and allied health (82%) programs having the highest rates. Fewer than half of undergraduate medical (43%) and dentistry (46%) programs offered IPV content. Postgraduate programs ranged from no IPV content provision (dentistry) to 41% offering content (nursing). Conclusion: Significant variability exists across program areas regarding the methods for IPV education, its delivery and evaluation. The results of this project highlight that expectations for an active and consistent response by health care professionals to women experiencing the effects of violence may not match the realities of professional preparation