945 resultados para self-defocusing photorefractive media, unbiased photorefractive media, low divergence interactions


Relevância:

100.00% 100.00%

Publicador:

Resumo:

As a kind of mood, depression is one of the emotions which people experienced usually. Depressive disorder is one of the common mental diseases. There are about 100 million people in the world be disturbed by depression every year. So it is long history that depression is investigated widely in medicine, psychology, and sociology. There are many theorial problems remain to be solved. Viewed from latest vocuments, the development of depression theory is tending to become more complicated. Most of the prior depression theory focused on relation between one factor and depression. Because depressed individuls have various characteristics and factors that cause depression are different, and each factor can explain only part of depression variance, these prior depression theories are defected. As the knowledge about depression accumulated, the view that depression be caused by multifactor is clearer. There is tendency to integrate these cooperational factor into a model while developing a depression theory. In the present study, depression status of 1625 middle school students from junior 1 to senior 3 are measured using Depression Scale of Middle-school Student which is developed by ourselves. From approach of depressive mood, the present study explored depressive diathesis including attributional style, personality, coping style, and self. The relation among depressive diathesis, stress and depression is analysed. The relation between depression and school life adaptation, depression and cohesion, adaptation in family are also analysed from environmental view. At last, relation among environment, stress, depressive diathesis is examined by using covariance structure modelling. Synthesizing the results from the present study, the following conclusions were drawn: (1) There is grade-characteristics in development of depression in middle school students. Depression degree increased with grade. The main reason may be that the stress middle-school students experience increase and self-acceptance decrease with grade; (2) High depressive diathesis is different from low depressive diathesis. the features of high depressive diathesis are that attributing failure to ability or background, low capacity for status, low sociability, low independence, low self-blame, more illusion. The features of low depressive diathesis are that not attributing failure to ability or background, high capacity for status, high sociability, high independence, high self-acceptance, while facing difficulties, using problem-resolving coping strategy, less self-blame, less illusion. Individuals who have high depressive diathesis showed serious depression, and individuals who have low depressive diathesis showed light depression; (3) Depressive diathesis had accumulative effect on depression. More low depressive diathesis, more light is depression. More high depressive diathesis, more serious is depression; (4) Depressive diathesis can predict present depression and future depression. Predicting present depression is more effective than predicting future depression; (5) Individual who has different depressive diathesis experiences different level of stress. Higher the depressive diathesis individual has, higher stress he will experience. Lower the depressive diathesis individual has, lower stress will he experience; (6) There is correlation between life event pressure and depression. Life event pressure can predict a part of variance of depression. Life event pressure has accumulative effect on depression. More life event and higher life event pressure, more serious depression individual will experience; (7) There exits high correlation between depression and school life adaptation which can predict depression; (8) There is high correlative relation between depression and cohesion, adaptation in family which can predict depression; and (9) Environment have more effect on diathesis than on stress. Diathesis has more effect on depression than stress does. The past depression can predict future depression. This study had enlarged the domain of depressive diathesis such as attributional style, personality, coping style, and self, which are analysed wholly. This study had also enriched the connotation of diathesis=stress theory. Above two aspects are theoretical significance of the study. This study provide a framework of mental health educational curriculum in high school and provide the guideline for prevention and cure of depression. It is the practical significance of this study.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Speaking out about sexual violence has been a fundamental part of feminist politics since the 1970s. The practice of narrating experiences of violence, either publicly or to friends and family aims to combat the culture of silence and stigmatisation that surrounds sexual violence while also helping individuals to gain a sense of empowerment and connect with other survivors. However, speaking out also contains inherent risks, especially for young people. Survivors may meet with stigmatising or disbelieving responses, and they may lose control over who knows their story and the way in which it is told and retold.
These risks and benefits are altered, and potentially exacerbated, in an online environment. While social media may increase survivors’ ability to contact and connect with others with similar experiences it also makes it harder to control when and how their story is shared. The disjuncture between online and offline environments may also increase feelings of stigmatisation and isolation.
There is a need to explore the specific risks and benefits of speaking out online given both young people’s extensive use of social media for social interactions and the increasing tendency for support and educational services targeted at young people to make use of social media and online environments. This paper draws on literature and some preliminary research to consider both risks and benefits of speaking out online and to open a conversation about the creation of supportive spaces and mechanisms for young people to speak about sexual violence in online environments.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Ion acceleration driven by the interaction of an ultraintense (2 × 1020 W cm-2) laser pulse with an ultrathin ( nm) foil target is experimentally and numerically investigated. Protons accelerated by sheath fields and via laser radiation pressure are angularly separated and identified based on their directionality and signature features (e.g. transverse instabilities) in the measured spatial-intensity distribution. A low divergence, high energy proton component is also detected when the heated target electrons expand and the target becomes relativistically transparent during the interaction. 2D and 3D particle-in-cell simulations indicate that under these conditions a plasma jet is formed at the target rear, supported by a self-generated azimuthal magnetic field, which extends into the expanded layer of sheath-accelerated protons. Electrons trapped within this jet are directly accelerated to super-thermal energies by the portion of the laser pulse transmitted through the target. The resulting streaming of the electrons into the ion layers enhances the energy of protons in the vicinity of the jet. Through the addition of a controlled prepulse, the maximum energy of these protons is demonstrated experimentally and numerically to be sensitive to the picosecond rising edge profile of the laser pulse.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

PURPOSE:

To determine the accuracy of a history of cataract and cataract surgery (self-report and for a sibling), and to determine which demographic, cognitive, and medical factors are predictive of an accurate history.

METHODS:

All participants in the Salisbury Eye Evaluation (SEE) project and their locally resident siblings were questioned about a personal and family history of cataract or cataract surgery. Lens grading at the slit lamp, using standardized photographs and a grading system, was performed for both SEE participants (probands) and their siblings. Cognitive testing and a history of systemic comorbidities were also obtained for all probands.

RESULTS:

Sensitivity of a history of cataract provided on behalf of a sibling was 32%, specificity 98%. The performance was better for a history of cataract surgery: sensitivity 90%, specificity 89%. For self-report of cataract, sensitivity was also low at 55%, with specificity at 77%. Self-report of cataract surgery gave a much better performance: sensitivity 94%, specificity 100%. Different cutoffs in the definition of cataract had little impact. Factors predicting a correct history of cataract included high school or greater education in the proband (odds ratio [OR] = 1.13, 95% confidence interval [CI]1.02-1.25) and younger sibling (but not proband) age (OR = 0.94 for each year of age, 95% CI 0.90-0.99). Gender, race and Mini-Mental Status Examination (MMSE) result were not predictive.

CONCLUSIONS:

Whereas accurate self and family histories for cataract surgery may be obtainable, it is difficult to ascertain cataract status accurately from history alone.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In this article we present the spectral and nonlinear optical properties of ZnO–TiO2 nanocomposites prepared by colloidal chemical synthesis. Emission peaks of ZnO–TiO2 nanocomposites change from 340 nm to 385 nm almost in proportion to changes in Eg. The nanocomposites show self-defocusing nonlinearity and good nonlinear absorption behaviour. The nonlinear refractive index and the nonlinear absorption increase with increasing TiO2 volume fraction at 532 nm and can be attributed to the enhancement of exciton oscillator strength. ZnO–TiO2 is a potential nanocomposite material for the tunable light emission and for the development of nonlinear optical devices with a relatively small limiting threshold

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In this article, we present the spectral and nonlinear optical properties of ZnO–CdS nanocomposites prepared by colloidal chemical synthesis. The optical band gap (Eg) of the material is tunable between 2.62 and 3.84 eV. The emission peaks of ZnO–CdS nanocomposites change from 385 to 520 nm almost in proportion to changes in Eg. It is possible to obtain a desired luminescence color from UV to green by simply adjusting the composition. The nonlinear optical response of these samples is studied by using nanosecond laser pulses from a tunable laser at the excitonic resonance and off-resonance wavelengths. The nonlinear response is wavelength dependent, and switching from saturable absorption (SA) to reverse SA (RSA) has been observed for samples as the excitation wavelength changes from the excitonic resonance to off-resonance wavelengths. Such a changeover in the sign of the nonlinearity of ZnO–CdS nanocomposites is related to the interplay of exciton bleach and optical limiting mechanisms. The ZnO–CdS nanocomposites show self-defocusing nonlinearity and good nonlinear absorption behavior at off-resonant wavelengths. The nonlinear refractive index and the nonlinear absorption increase with increasing CdS volume fraction at 532 nm. The observed nonlinear absorption is attributed to two photon absorption followed by weak free carrier absorption. The enhancement of the third-order nonlinearity in the composites can be attributed to the concentration of exciton oscillator strength. This study is important in identifying the spectral range and composition over which the nonlinear material acts as a RSA based optical limiter. ZnO–CdS is a potential nanocomposite material for the tunable light emission and for the development of nonlinear optical devices with a relatively small limiting threshold.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In this Letter we present the spectral and nonlinear optical properties of ZnO–Ag nanocomposites prepared by colloidal chemical synthesis. Obvious enhancement of ultraviolet (UV) emission of the samples is observed and the strongest UV emission is over three times than that of pure ZnO. These nanocomposites show self-defocusing nonlinearity and good nonlinear absorption behaviour which increases with increasing Ag volume fraction. The observed nonlinear absorption is explained through two photon absorption followed by free carrier absorption. ZnO–Ag is a potential nanocomposite material for the UV light emission and for the development of nonlinear optical devices with a relatively small limiting threshold.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Las redes sociales digitales han transformado la forma de comunicarse en el Siglo XXI. Twitter es la red social más destacada para los periodistas colombianos pues según un estudio de la consultora de comunicación Burson-Marsteller, el 47% de los comunicadores colombianos utilizan esta red social para construir noticias (Burson-Marsteller, 2013). Por su popularidad, los medios de comunicación han puesto la mirada sobre esta red social pues ven en esta un nuevo espacio de información, razón por la cual se han transformado para convertir a Twitter en un nuevo conducto para la transmisión de sucesos coyunturales. En Colombia, los medios periodísticos de tradición intentan modificar su estructura y rutinas para adecuarse al nuevo molde comunicativo que propone la inclusión de las redes sociales digitales. Este artículo intenta desvelar cuáles son esos cambios que ha sufrido el periodismo colombiano, teniendo como base su relación con Twitter.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

BACKGROUND: Reminder systems in electronic patient records (EPR) have proven to affect both health care professionals' behaviour and patient outcomes. The aim of this cluster randomised trial was to investigate the effects of implementing a clinical practice guideline (CPG) for peripheral venous catheters (PVCs) in paediatric care in the format of reminders integrated in the EPRs, on PVC-related complications, and on registered nurses' (RNs') self-reported adherence to the guideline. An additional aim was to study the relationship between contextual factors and the outcomes of the intervention. METHODS: The study involved 12 inpatient units at a paediatric university hospital. The reminders included choice of PVC, hygiene, maintenance, and daily inspection of PVC site. Primary outcome was documented signs and symptoms of PVC-related complications at removal, retrieved from the EPR. Secondary outcome was RNs' adherence to a PVC guideline, collected through a questionnaire that also included RNs' perceived work context, as measured by the Alberta Context Tool. Units were allocated into two strata, based on occurrence of PVCs. A blinded simple draw of lots from each stratum randomised six units to the control and intervention groups, respectively. Units were not blinded. The intervention group included 626 PVCs at baseline and 618 post-intervention and the control group 724 PVCs at baseline and 674 post-intervention. RNs included at baseline were 212 (65.4 %) and 208 (71.5 %) post-intervention. RESULTS: No significant effect was found for the computer reminders on PVC-related complications nor on RNs' adherence to the guideline recommendations. The complication rate at baseline and post-intervention was 40.6 % (95 % confidence interval (CI) 36.7-44.5) and 41.9 % (95 % CI 38.0-45.8), for the intervention group and 40.3 % (95 % CI 36.8-44.0) and 46.9 % (95 % CI 43.1-50.7) for the control. In general, RNs' self-rated work context varied from moderately low to moderately high, indicating that conditions for a successful implementation to occur were less optimal. CONCLUSIONS: The reminders might have benefitted from being accompanied by a tailored intervention that targeted specific barriers, such as the low frequency of recorded reasons for removal, the low adherence to daily inspection of PVC sites, and the lack of regular feedback to the RNs. TRIAL REGISTRATION: Current Controlled Trials ISRCTN44819426.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The HiPER reactor design is exploring different reaction chambers. In this study, we tackle the neutronicsand activation studies of a preliminary reaction chamber based in the following technologies: unpro-tected dry wall for the First Wall, self-cooled lead lithium blanket, and independent low activation steelVacuum Vessel. The most critical free parameter in this stage is the blanket thickness, as a function ofthe6Li enrichment. After a parametric study, we select for study both a ?thin? and ?thick? blanket, with?high? and ?low?6Li enrichment respectively, to reach a TBR = 1.1. To help to make a choice, we com-pute, for both blanket options, in addition to the TBR, the energy amplification factor, the tritium partialpressure, the203Hg and210Po total activity in the LiPb loop, and the Vacuum Vessel thickness requiredto guarantee the reweldability during its lifetime. The thin blanket shows a superior performance in thesafety related issues and structural viability, but it operates at higher6Li enrichment. It is selected forfurther improvements. The Vacuum Vessel shows to be unviable in both cases, with the thickness varyingbetween 39 and 52 cm. Further chamber modifications, such as the introduction of a neutron reflector,are required to exploit the benefits of the thin blanket with a reasonable Vacuum Vessel.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The Community Services Block Grant (CSBG) Program was created by the federal Omnibus Budget Reconciliation Act of 1981. The CSBG Program provides a range of services which assist low-income people to attain the skills, knowledge and motivation necessary to achieve self-sufficiency. The program also may offer low-income people immediate life necessities such as food, shelter, medication, etc.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Wireless Mesh Networks (WMNs), based on commodity hardware, present a promising technology for a wide range of applications due to their self-configuring and self-healing capabilities, as well as their low equipment and deployment costs. One of the key challenges that WMN technology faces is the limited capacity and scalability due to co-channel interference, which is typical for multi-hop wireless networks. A simple and relatively low-cost approach to address this problem is the use of multiple wireless network interfaces (radios) per node. Operating the radios on distinct orthogonal channels permits effective use of the frequency spectrum, thereby, reducing interference and contention. In this paper, we evaluate the performance of the multi-radio Ad-hoc On-demand Distance Vector (AODV) routing protocol with a specific focus on hybrid WMNs. Our simulation results show that under high mobility and traffic load conditions, multi-radio AODV offers superior performance as compared to its single-radio counterpart. We believe that multi-radio AODV is a promising candidate for WMNs, which need to service a large number of mobile clients with low latency and high bandwidth requirements.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The role of support from teachers on the academic and emotional adjustment of a ethnically and economically diverse sample of adolescents was examined. Analyses were conducted on data from a larger study examining social networks across the transition to junior high school. Participants in the current study included 694 African-American, Hispanic-American and European-American students in grades 6 and 8 from public elementary schools in South Florida. Some of these schools are located in economically distressed areas and some are in middle income areas. Children were interviewed, and information on teacher social support resources, school stressors, risk and academic and emotional adjustment was obtained. Several significant findings emerged from the analyses. First, overall teacher support was a significant predictor of a wide range of academic and emotional adjustment outcomes. Second, teacher support compensated for low peer support on teacher rated behavior problems. Third, teacher support interacted with school stress to predict depressed affect and self esteem. Fourth, teacher support interacted with low ecological risk conditions to predict feelings of loneliness. ^

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Ostomy is an open surgical origin, when it is necessary to deviate temporarily or permanently, the normal transit of food and / or deletions. The patient with ostomy disposal is faced with changes in their physiology, also emerging on the need to care collection bag. This study aimed to analyze the quality of life (QOL) of people living with ostomy Intestinal (EI), who attended the Pediatric and Adult Rehabilitation Center of Rio Grande do Norte (CRI / CRA-RN). It is an analytical study with cross-sectional design and quantitative approach, accomplished with 89 people who had EI. The study was approved by the Ethics Committee of the Federal University of Rio Grande do Norte (CEP / UFRN), CAAE: 19866413.3.0000.5537. Held data collection in the period January-March 2015 using two instruments: an adapted general questionnaire covering socio-demographic, clinical and self-care and a specific instrument for assessing QOL of people with stoma titled as City of Hope Quality of Life - Ostomy Questionnaire (COH-QOL-Q), validated and adapted to Portuguese in 2010, composed of four areas, namely: Welfare Body (BEF), Welfare Psychological (BEP), Welfare (BES ) and Spiritual Well-Being (BEE). The collected data were entered into a database in Microsoft Excel 2007 spreadsheet application and processed in computerized software for descriptive and inferential analysis. The results showed that 83.1% had a colostomy and ileostomy 16.9%. Sociodemographic characteristics prevailed in males (57.3%), over 50 (57.3%), mulatto (46.1%), with presence of companion / a (57.3%), retired / beneficiaries (50.5%), monthly income above the minimum wage (68.5%) and who have studied up to elementary school (67.4%). Regarding clinical aspects, it was observed that the main cause that led to the making of the stoma was the neoplasm (59.6%) followed by trauma (21.3%). The sample showed people with stoma for more than six months (79.8%) of permanently (57.3%), in use sink equipment piece drainable (68.5%) of flat base (82.0%). With respect to self-care, 93.3% emptied and washed the bag alone (care related to hygiene) and 75.3% fixed the new exchange on the skin during the exchange (care related to the stock). Patients with more than six months of ostomy and had no partner (a) had higher averages of self-care related hygiene and purse. The average of respondents QoL scores was 68.90% for General QOL; 68.03% for the BEF; 68.38% for the BEP; 66.46% for BES and 75.41% for BEE. Among the aspects that influenced QOL included: physical strength, pain, suffering and gases (physical domain); appearance, care of the stoma and adaptation to new condition (psychological domain); isolation, interference in personal relationships and social activities (social domain) and going to church or synagogue, spiritual activities and positive change after ostomy (spiritual realm). Based on these results, it is concluded that this was a predominantly adult sample / elderly (between 50 and 70 years), with low education and the cause motivating the stoma, neoplasms. However, such findings did not pass at low percentage levels on the self-care capacity to deliver even at low QOL scores.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Ostomy is an open surgical origin, when it is necessary to deviate temporarily or permanently, the normal transit of food and / or deletions. The patient with ostomy disposal is faced with changes in their physiology, also emerging on the need to care collection bag. This study aimed to analyze the quality of life (QOL) of people living with ostomy Intestinal (EI), who attended the Pediatric and Adult Rehabilitation Center of Rio Grande do Norte (CRI / CRA-RN). It is an analytical study with cross-sectional design and quantitative approach, accomplished with 89 people who had EI. The study was approved by the Ethics Committee of the Federal University of Rio Grande do Norte (CEP / UFRN), CAAE: 19866413.3.0000.5537. Held data collection in the period January-March 2015 using two instruments: an adapted general questionnaire covering socio-demographic, clinical and self-care and a specific instrument for assessing QOL of people with stoma titled as City of Hope Quality of Life - Ostomy Questionnaire (COH-QOL-Q), validated and adapted to Portuguese in 2010, composed of four areas, namely: Welfare Body (BEF), Welfare Psychological (BEP), Welfare (BES ) and Spiritual Well-Being (BEE). The collected data were entered into a database in Microsoft Excel 2007 spreadsheet application and processed in computerized software for descriptive and inferential analysis. The results showed that 83.1% had a colostomy and ileostomy 16.9%. Sociodemographic characteristics prevailed in males (57.3%), over 50 (57.3%), mulatto (46.1%), with presence of companion / a (57.3%), retired / beneficiaries (50.5%), monthly income above the minimum wage (68.5%) and who have studied up to elementary school (67.4%). Regarding clinical aspects, it was observed that the main cause that led to the making of the stoma was the neoplasm (59.6%) followed by trauma (21.3%). The sample showed people with stoma for more than six months (79.8%) of permanently (57.3%), in use sink equipment piece drainable (68.5%) of flat base (82.0%). With respect to self-care, 93.3% emptied and washed the bag alone (care related to hygiene) and 75.3% fixed the new exchange on the skin during the exchange (care related to the stock). Patients with more than six months of ostomy and had no partner (a) had higher averages of self-care related hygiene and purse. The average of respondents QoL scores was 68.90% for General QOL; 68.03% for the BEF; 68.38% for the BEP; 66.46% for BES and 75.41% for BEE. Among the aspects that influenced QOL included: physical strength, pain, suffering and gases (physical domain); appearance, care of the stoma and adaptation to new condition (psychological domain); isolation, interference in personal relationships and social activities (social domain) and going to church or synagogue, spiritual activities and positive change after ostomy (spiritual realm). Based on these results, it is concluded that this was a predominantly adult sample / elderly (between 50 and 70 years), with low education and the cause motivating the stoma, neoplasms. However, such findings did not pass at low percentage levels on the self-care capacity to deliver even at low QOL scores.