926 resultados para Secondary species and climactic species
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Purpose: To evaluate the clinical features, treatment, and outcomes of a cohort of patients with ocular adnexal lymphoproliferative disease classified according to the World Health Organization modification of the Revised European-American Classification of Lymphoid neoplasms and to perform a robust statistical analysis of these data. Methods: Sixty-nine cases of ocular adnexal lymphoproliferative disease, seen in a tertiary referral center from 1992 to 2003, were included in the study. Lesions were classified by using the World Health Organization modification of the Revised European-American Classification of Lymphoid neoplasms classification. Outcome variables included disease-specific Survival, relapse-free survival, local control, and distant control. Results: Stage IV disease at presentation, aggressive lymphoma histology, the presence of prior or concurrent systemic lymphoma at presentation, and bilateral adnexal disease were significant predictors for reduced disease-specific survival, local control, and distant control. Multivariate analysis found that aggressive histology and bilateral adnexal disease had significantly reduced disease-specific Survival. Conclusions: The typical presentation of adnexal lymphoproliferative disease is with a painless mass, swelling, or proptosis; however, pain and inflammation occurred in 20% and 30% of patients, respectively. Stage at presentation, tumor histology, primary or secondary status, and whether the process was unilateral or bilateral were significant variables for disease outcome. In this study, distant spread of lymphoma was lower in patients who received greater than 20 Gy of orbital radiotherapy.
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Background: Study of the course of substance misuse and daily tobacco use in first-episode psychosis may enhance detection and treatment of these substance-related problems. Methods: This 15-month follow-up study examined the course of substance misuse and daily tobacco use in 103 individuals treated for first-episode psychosis. Results: Three-quarters (72.6%) of patients with lifetime substance misuse, or half (51.5%) of all patients, continued substance misuse (primarily cannabis) during the 15-month follow-up period. There was a significant reduction in the rate of any substance misuse (70.9% versus 53.4%) but not daily tobacco use (76.7% versus 75.7%) between baseline and 15-month follow-up. Patients who continued substance misuse showed a significant reduction in the severity and frequency of substance use between baseline and follow-up. Patients who continued substance misuse were more likely to be younger, male and single, less likely to have completed secondary school, and more likely to have had more severe cannabis use prior to entry to treatment compared to patients who ceased substance misuse. Discussion: A significant proportion of young patients treated for first-episode psychosis are at risk of mental and physical health problems associated with substance misuse and/or regular tobacco use. (c) 2005 Elsevier B.V. All rights reserved.
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Review date: Review period January 1992-December 2001. Final analysis July 2004-January 2005. Background and review context: There has been no rigorous systematic review of the outcomes of early exposure to clinical and community settings in medical education. Objectives of review: (1) Identify published empirical evidence of the effects of early experience in medical education, analyse it, and synthesize conclusions from it. (2) Identify the strengths and limitations of the research effort to date, and identify objectives for future research. Search strategy: Ovid search of. BEI, ERIC, Medline, CIATAHL and EMBASE Additional electronic searches of: Psychinfo, Timelit, EBM reviews, SIGLE, and the Cochrane databases. Hand-searches of: Medical Education, Medical Teacher, Academic Medicine, Teaching and Learning in Medicine, Advances in Health Sciences Education, Journal of Educational Psychology. Criteria: Definitions: Experience: Authentic (real as opposed to simulated) human contact in a social or clinical context that enhances learning of health, illness and/or disease, and the role of the health professional. Early: What would traditionally have been regarded as the preclinical phase, usually the first 2 years. Inclusions: All empirical studies (verifiable, observational data) of early experience in the basic education of health professionals, whatever their design or methodology, including papers not in English. Evidence from other health care professions that could be applied to medicine was included. Exclusions: Not empirical; not early; post-basic; simulated rather than 'authentic' experience. Data collection: Careful validation of selection processes. Coding by two reviewers onto an extensively modified version of the standard BEME coding sheet. Accumulation into an Access database. Secondary coding and synthesis of an interpretation. Headline results: A total of 73 studies met the selection criteria and yielded 277 educational outcomes; 116 of those outcomes (from 38 studies) were rated strong and important enough to include in a narrative synthesis of results; 76% of those outcomes were from descriptive studies and 24% from comparative studies. Early experience motivated and satisfied students of the health professions and helped them acclimatize to clinical environments, develop professionally, interact with patients with more confidence and less stress, develop self-reflection and appraisal skill, and develop a professional identity. It strengthened their learning and made it more real and relevant to clinical practice. It helped students learn about the structure and function of the healthcare system, and about preventive care and the role of health professionals. It supported the learning of both biomedical and behavioural/social sciences and helped students acquire communication and basic clinical skills. There were outcomes for beneficiaries other than students, including teachers, patients, populations, organizations and specialties. Early experience increased recruitment to primary care/rural medical practice, though mainly in US studies which introduced it for that specific purpose as part of a complex intervention. Conclusions: Early experience helps medical students socialize to their chosen profession. It. helps them acquire a range of subject matter and makes their learning more real and relevant. It has potential benefits for other stakeholders, notably teachers and patients. It can influence career choices.
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Background: The aim of the study was to investigate the prevalence of injecting drug use and associated risk behaviour among a sentinel sample of ecstasy users. Methods: Cross-sectional surveys were conducted with regular ecstasy users as part of an annual monitoring study of ecstasy and related drug markets in all Australian capital cities. Results: Twenty-three percent of the sample reported having ever injected a drug and 15% reported injecting in the 6 months preceding interview. Independent predictors of lifetime injection were older age, unemployment and having ever been in prison. Completion of secondary school and identifying as heterosexual was associated with a lower likelihood of having ever injected. Participants who had recently injected typically did so infrequently; only 9% reported daily injecting. Methamphetamine was the most commonly injected drug. Prevalence of needle sharing was low (6%), although half (47%) reported sharing other injecting equipment in the preceding 6 months. Conclusions: Ecstasy users who report having injected a drug at some time appear to be demographically different to ecstasy users who have not injected although neither are they typical of other drug injectors. The current investigation suggests that ongoing monitoring of injecting among regular ecstasy users is warranted. (c) 2005 Elsevier Ireland Ltd. All rights reserved.
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Background: Despite the availability of expert surgeons and preoperative imaging investigations, some patients require reoperation for persistent or recurrent hyperparathyroidisms. Method: Fifty consecutive patients were reviewed. Results: There were 28 persistent cases (24 primary, 4 secondary) and 22 recurrent cases (15 primary, 7 secondary) and 98% had successful surgical treatment. Multigland disease was present in 24 of 39 (62%) of primary cases, 11 of 24 persistent and 13 of 15 recurrent (P < 0.02). Four patients in the recurrent primary group had multiple endocrine neoplasia type 1, whereas the other 20 primary patients had sporadic multigland disease. Multigland disease was present in all secondary cases and was a very important factor in this entire series of patients (70%). Regrowth of a remnant of a gland biopsied or partially resected at an earlier operation was the cause of recurrence in 12 of 15 primary and 2 of 7 secondary cases (P < 0.05). The site of missed glands in persistent disease was ectopic in 60%. Ectopic glands were found in the following sites: intrathyroidal 10 (8 inferior and 2 superior), intrathymic 9, posterior mediastinum 4, base of skull 2, carotid sheath 1 and supernumerary 5. Investigations to locate missing glands were positive in 28 of 43 sestamibi scans (65%), 14 of 34 ultrasound scans (41%), 10 of 24 computed tomography scans (42%) and 11 of 13 selective venous sampling tests (85%). Conclusion: Some persistent cases are unavoidable because of ectopic locations and some recurrences are inevitable because of multigland disease.
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There is little doubt that devolution of responsibility to schools and the growth of school-based management have impacted upon the role and workload of school leaders. Not only Principals have been affected by these changes as Welch (1996) argues that Principals of public secondary schools have passed responsibility down to Deputy-principals and to Heads of Department. As such, the Head of Department role, like other school administration positions, has undergone significant change. Of interest to this paper is the changing role of Heads of Department in secondary schools. This study reports on the findings of semi-structured interviews with eight Heads of Department from four public secondary schools and Principals from each of these schools in South East Queensland. Four years after the first set of interviews, two heads of department were reinterviewed. Both sets of interviews focused upon the role, change, and the importance of leadership. The research generated eight specific themes each of which was considered consistent with the nature of the role in a period of significant cultural change. These were the difference in perceptions regarding the Head of Department role, held by Principals and Heads of Department; Head of Department leadership in terms of a curriculum framed department or whole school leadership; how individuals perceived leadership, and how they learned of leadership; the impact of the changing culture upon the individual Head of Department; the growing influence of situational factors upon the role; the impact of managerialism; the changing nature of a secondary school department; and a growing and more complex workload, and the need for different skills. Furthermore, the findings pointed towards the need for effective change processes and a reconceptualized head of department role. The paper concludes with some implications for the ongoing professional development needs of Heads of Department.
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The majority of ‘service’ literature has focused on the production side of service work (i.e. employees and management), while treating the role of the customer and/or consumer as secondary (Korczynski and Ott, 2004). Those authors who have addressed the role consumption plays in shaping and maintaining individuals' self- identity have tended to overemphasize the dominance of consumer culture in shaping ‘our consciousness’ (Ritzer, 1999), with little in the way of empirical evidence to support these assertions. This paper develops the conceptualization of service work and consumer culture literature, by placing more emphasis on the customer in the service encounter. Using an ethnographic study of a ‘high class’ department store, this paper addresses employee and customer identity and the nature of managerial, employee and customer control within this ‘exclusive’ context. Of particular interest is how employees and customer’s ‘embody’ this control. Using Bourdieu’s (1986) conception of class and habitus, the concept of exclusivity goes beyond the management /service worker dyad by providing a means of investigating identity control by the organization over both customers and service workers. However, an organization’s exclusivity is not a closed normative pursuit of control, and shows this enterprise is part of a contested terrain, while revealing the ambiguity and ‘openness’ of control practices and pursuits. In order to uphold the ideal of exclusivity, management, service workers and customers must all engage in a precarious quest for establishing and maintaining a sense of control and/or identity. This paper demonstrates the continuing contradiction between bureaucratic practices of control and consumer culture, and highlights the need for research that investigates the context -dependent nature of control in service-related and consumer studies.
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AIDS (Acquired Immune Deficiency Syndrome)was first, described as a new disease of humans in 1981. The origins of the disease are controversial. AIDS is caused by a retrovirus, a type of virus which rarely attacks human cells. The first virus of this type recorded in humans is reponsible for a type of leukaemia and was identified in 1978. AIDS is thus the third type of human retrovirus to be discovered and hence, is referred to as T-lymphotrophic virus III (HTLV-III). For viruses to replicate, they have to invade a host cell which in this case is a T4-lymphocyte, a type of white blood cell that regulates the immune system. The problems of the disease result directly from the death of these cells. As a consequence, the immune system is compromised leading to a number of opportunistic secondary infections and other disorders.
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Purpose – The purpose of this paper is to illustrate Michael Thomas's concept of civic professionalism and social trusteeship as a future alternative to the current marketing profession's code of conduct and to put this in the context of climate change and ecological sustainability as a model for firms everywhere. Design/methodology/approach – Review of the marketing profession's responsibility towards society, communities and the ecology of the planet in the twenty-first century in the light of climate change. Findings – The hypothesis for the paper emerges as: whether it is possible for Chinese firms to embrace the needs of twenty-first century global ecological sustainability in meeting their own economic requirements for development and financial prosperity. Research limitations/implications – Limited secondary research and primary research that is also limited in terms of scope. Practical implications – As we move into an era of Chinese economic supremacy, we marketers must face up to the responsibility we have towards balancing the progression of global economic development (and selling goods and services in global market systems) with our responsibility towards our cultural systems and the global ecological system (the global ecosystem), the home of all our economic wealth. Social implications – To extrapolate lessons and opportunities for firms from developing economies as they move towards global domination of world economic markets and, suggest strategies for sustainability that they can, and should, adopt. Originality/value – The paper presents a theoretical framework for a global strategy for sustainability, and provides a vision of marketing responsibility that embraces civic professionalism, social trusteeship and a strategy for sustainability.
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Responsive hydrophobically associating polymers can in many ways be considered to be analogous to proteins in their ability to form compact molecules with a defined secondary structure, and hence, functionality. These molecules are characterized by the presence of alternating charged and hydrophobic groups. The balance between charge repulsion and hydrophobic interactions is sensitive to environmental pH and therefore changes in pH produce controllable conformational changes. The change from a charged extended chain to a collapsed uncharged coil structure is sometimes referred to as hypercoiling behaviour and enables the polymer to act as a simple switch between an 'on' and 'off' state. The purpose of this review is to illustrate the structure and behaviour of polymers that exhibit hypercoiling behaviour and to highlight their potential pharmaceutical applications, which in terms of drug delivery is likely to be related to their surface behaviour and solubilizing activity. © 2001 Elsevier Science B.V. All rights reserved.
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PURPOSE: To assess the correlation between changes in corneal aberrations and the 2-year change in axial length in children fitted with orthokeratology (OK) contact lenses. METHODS: Thirty-one subjects 6 to 12 years of age and with myopia −0.75 to −4.00DS and astigmatism ≤1.00DC were fitted with OK. Measurements of axial length and corneal topography were taken at regular intervals over a 2-year period. Corneal topography at baseline and after 3 and 24 months of OK lens wear was used to derive higher-order corneal aberrations (HOA) that were correlated with OK-induced axial length changes at 2 years. RESULTS: Significant changes in C3, C4, C4, root mean square (RMS) secondary astigmatism and fourth and total HOA were found with both 3 and 24 months of OK lens wear in comparison with baseline (all P0.05). Coma angle of orientation changed significantly pre-OK in comparison with 3 and 24 months post-OK as well as secondary astigmatism angle of orientation pre-OK in comparison with 24 months post-OK (all P0.05). DISCUSSION: Short-term and long-term OK lens wear induces significant changes in corneal aberrations that are not significantly correlated with changes in axial elongation after 2-years.
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Most ethnopharmacological studies overlook food plants, yet many edible plants, also have medicinal value. I documented plants that are used as both food and medicine by the Totonac of Zapotitlan de Mendez, Mexico and recorded the presence of selected secondary compounds, and physical characteristics in these plants. Photoactivity, antimicrobial, and antifungal assays also were performed. The presence of these properties were compared among food/medicine plants, food, medicinal, and randomly selected plants. I predicted that a higher percentage of medicinal plants would contain the secondary compounds, physical characteristics, and bioactivity compared to the other groups. Phenolics and cyanogenic glycosides in the medicinal group were significantly greater than in the food/medicine group. The food plants did not differ greatly from the medicinal plants. This research indicates that including food plants in ethnomedical studies could provide a more complete knowledge of peoples therapeutic resources and practices. ^
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This study investigated the perceptions of writing among secondary and post-secondary students and their teachers. The focus was on students' writing philosophy and influences, perceptions of the writing process, and perceptions of student writing skills, high stakes assessment tests, and writing across the curriculum. ^ An ethnographic case study was used to investigate the perceptions of writing among ten students and their English teachers in two high schools, a community college, and a university. To establish balance and ethnic plurality, seven females and three males representing the four large ethnic groups in South Florida—African American, Haitian American, European American and Latino—participated. During one four-month term, data from written samples of students' writing, formal and informal interviews, a student focus group, field notes, classroom observations, and a “think-aloud” protocol were collected. ^ Four themes emerged. First, Florida's writing assessment test has a negative influence on students' perceptions of writing. Students' motivation and attitudes as well as their confidence in their abilities were affected by practice and preparation in “recital writing.” Second, writing is a vehicle of social and personal transformation. Students believed that writing is a mean to connect to others and to create change in schools and communities. Third, students lacked the ability to connect writing, thinking and learning. Although students and teachers agree with statements about this connection, students failed to see the relevance of thinking and learning through writing in current or future courses, or in their future careers. Finally, writing context, teachers, schools, peers and gender influenced writing perceptions. Students believed that their writing philosophy, writing process, and perceptions of writing in academia and in the workplace are connected to these five factors. ^ The effect of the Florida writing test pervades students' and teachers' writing perceptions, making a stronger case for writing across the curriculum than previous research. Writing should help students see knowledge as interrelated, honor students' interests and values, and build relationships between and among students, schools and communities. In designing and implementing methods that support and sustain student writing, teachers should provide students with multiple opportunities to expand knowledge, learning, and connection through writing. ^
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There is a commonly presumed link among sexual risk behavior, substance use, and other psychosocial factors among adolescents. However, these relationships have been relatively understudied in detained, low-income, minority, substance abusing adolescents. This study addresses this gap in the literature with a secondary data analysis based on a sample of adolescent offenders in two detention and treatment centers in Miami-Dade County. Univariate, bivariate statistical analysis and multivariate logistic regressions were conducted on baseline data from structured interviews with 455 adolescents participating in an NIH funded prevention intervention. Data were analyzed to assess relationships among self-reported substance use, STD history, HIV/AIDS knowledge, condom use, condom use attitudes, and skills, peer and parental approval to use condoms, and race/ethnicity. The adolescent sample was 74.1% male, and 25.9% female and 35.4% African American, 25.1% non-African American Latino, 11.2% White, and 28.4% of other race/ethnicity categories. The mean age was 15.6 years. Results suggested that alcohol use (p < 0.001) and use of marijuana, cocaine and other drugs (p < 0.001) are significant variables when explaining the variability in sexual risk behaviors. Results also suggested that unprotected vaginal, anal, and oral sex increased with higher alcohol and drug use (p < 0.001) and that positive attitudes about personally using condoms (p < 0.001) were also significantly related to condom use. Logistic regressions showed that race/ethnicity was a significant control variable when explaining the variability of condom use. Being White and Latino were significantly associated with less condom use during oral and anal sex when compared to other racial/ethnic groups. These results indicated that risky sexual behavior and HIV infection risk are significantly associated with substance use, particularly alcohol use. Therefore, proper screening and identification of alcohol use, and condom use attitudes could maximize the efficacy of referrals to programs targeting both issues and increase the potential for appropriate primary and secondary prevention and treatment among adolescent detainees.
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The aim of this research was to demonstrate a high current and stable field emission (FE) source based on carbon nanotubes (CNTs) and electron multiplier microchannel plate (MCP) and design efficient field emitters. In recent years various CNT based FE devices have been demonstrated including field emission displays, x-ray source and many more. However to use CNTs as source in high powered microwave (HPM) devices higher and stable current in the range of few milli-amperes to amperes is required. To achieve such high current we developed a novel technique of introducing a MCP between CNT cathode and anode. MCP is an array of electron multipliers; it operates by avalanche multiplication of secondary electrons, which are generated when electrons strike channel walls of MCP. FE current from CNTs is enhanced due to avalanche multiplication of secondary electrons and in addition MCP also protects CNTs from irreversible damage during vacuum arcing. Conventional MCP is not suitable for this purpose due to the lower secondary emission properties of their materials. To achieve higher and stable currents we have designed and fabricated a unique ceramic MCP consisting of high SEY materials. The MCP was fabricated utilizing optimum design parameters, which include channel dimensions and material properties obtained from charged particle optics (CPO) simulation. Child Langmuir law, which gives the optimum current density from an electron source, was taken into account during the system design and experiments. Each MCP channel consisted of MgO coated CNTs which was chosen from various material systems due to its very high SEY. With MCP inserted between CNT cathode and anode stable and higher emission current was achieved. It was ∼25 times higher than without MCP. A brighter emission image was also evidenced due to enhanced emission current. The obtained results are a significant technological advance and this research holds promise for electron source in new generation lightweight, efficient and compact microwave devices for telecommunications in satellites or space applications. As part of this work novel emitters consisting of multistage geometry with improved FE properties were was also developed.