92 research outputs found

    Comparison of metaheuristics for the firebreak placement problem: a simulation-based optimization approach

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    The problem of firebreak placement is crucial for fire prevention, and its effectiveness at landscape scale will depend on their ability to impede the progress of future wildfires. To provide an adequate response, it is therefore necessary to consider the stochastic nature of fires, which are highly unpredictable from ignition to extinction. Thus, the placement of firebreaks can be considered a stochastic optimization problem where: (1) the objective function is to minimize the expected cells burnt of the landscape; (2) the decision variables being the location of firebreaks; and (3) the random variable being the spatial propagation/behavior of fires. In this paper, we propose a solution approach for the problem from the perspective of simulation-based optimization (SbO), where the objective function is not available (a black-box function), but can be computed (and/or approximated) by wildfire simulations. For this purpose, Genetic Algorithm and GRASP are implemented. The final implementation yielded favorable results for the Genetic Algorithm, demonstrating strong performance in scenarios with medium to high operational capacity, as well as medium levels of stochasticit

    The effect of self-efficacy expectations in the adherence to a gluten free diet in celiac disease

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    Objective: To analyse the effect of general and specific self-efficacy on the adherence to a gluten free diet (GFD) in patients with celiac disease along with the effect of other relevant variables. Design: 271 patients with celiac disease participated in this transversal descriptive study and completed a series of questionnaires regarding adherence (CDAT), general self-efficacy (GSES) and specific self-efficacy (Celiac-SE) and quality of life (CD-Qol), among others. Main Outcome Measures: Dependent variable was adherence to the Gluten Free Diet (GFD). Main independent variables were general self-efficacy, specific self-efficacy and quality of life. Model tests were conducted using regression analysis. Results: 71.9% of patients show an excellent or good adherence to the diet. Higher levels of adherence are positively associated to a high expectancy of specific self-efficacy, to the perceived adoption of recommended behaviours, risk perception and better quality of life (these variables accounted for 36.4% of the variance in the adherence to a GFD, p <.001). Conclusions: Specific self-efficacy rather than general has a predictive value in adherence to a GFD. Therefore, we need to develop and transculturally adapt new instruments to assess specific self-efficacy. Celiac-SE has proved to be a useful scale for this objective

    Development and validation of a specific self-efficacy scale in adherence to a gluten-free diet

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    The aim of this study was to develop a scale to assess the levels of specific self-efficacy in order to enhance adherence to a gluten-free diet and the life quality of celiac patients. Celiac disease is a chronic small intestinal immune-mediated enteropathy precipitated by exposure to dietary gluten in genetically predisposed people. The only treatment is a strict lifelong gluten-free diet. Within the framework of Social Cognitive Theory, expectation of self-efficacy is understood as the degree in which a person believes himself to be capable of performing a certain task (e.g., adhering to a gluten-free diet), a construct which has been widely studied in its relation with adopting healthy behaviors, but scarcely in relation to celiac disease. A validation study was carried out in various stages: preparation of the protocol; construction of the questionnaire and a pilot run with 20 patients; validation of the scale with 563 patients and statistical analysis. A 25-item scale was developed. Feasibility was excellent (99.82% of participants completed all the questions). Factorial analysis pointed to the existence of five factors that explained 70.98% of the variance with a Cronbach alpha of 0.81 for the scale overall and between 0.64 and 0.90 for each factor. The scale showed a Spearman''s Rho coefficient of 0.279 with the General self-efficacy Scale. This easily administered scale provides good psychometric properties for evaluating specific self-efficacy of celiac patients in adhering to treatment. It seeks to be the first scale that provides not only a measurement of specific self-efficacy in celiac disease, but also to determine its levels for each of the areas as a first step toward designing interventions of self-management and empowerment programs to cope with the disease

    Estudio de prefactibilidad para la apertura de un almacén de calzado para damas, en el barrio La Roca de la localidad 4 de San Cristóbal, en la ciudad de Bogotá D.C.

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    Realizar un estudio de prefactibilidad para la apertura de un almacén de calzado para damas, en el barrio La Roca de la localidad 4 de San Cristóbal, en la ciudad de Bogotá D.C.El estudio de prefactibilidad que se plantea para la apertura de Almacén de Calzado en el Barrio La Roca, localidad 4 de San Cristobal Sur, se origina de una idea familiar que busca mejorar la calidad de vida de está familia, brindar a la comunidad una oportunidad de acceder al comercio del calzado y suplir sus necesidades, sin tener que llevar un largo tiempo en desplazamientos a zonas comerciales, igualmente, en busca de mejorar el entorno del barrio

    Estudio de prefactibilidad para la apertura de un almacén de calzado para damas, en el barrio La Roca de la localidad 4 de San Cristóbal, en la ciudad de Bogotá D.C.

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    Realizar un estudio de prefactibilidad para la apertura de un almacén de calzado para damas, en el barrio La Roca de la localidad 4 de San Cristóbal, en la ciudad de Bogotá D.C.El estudio de prefactibilidad que se plantea para la apertura de Almacén de Calzado en el Barrio La Roca, localidad 4 de San Cristobal Sur, se origina de una idea familiar que busca mejorar la calidad de vida de está familia, brindar a la comunidad una oportunidad de acceder al comercio del calzado y suplir sus necesidades, sin tener que llevar un largo tiempo en desplazamientos a zonas comerciales, igualmente, en busca de mejorar el entorno del barrio

    Influence of Compliance to Diet and Self-Efficacy Expectation on Quality of Life in Patients with Celiac Disease in Spain

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    The purpose of this study is to understand the health-related quality of life (HRQoL) in patients with celiac disease (CD) and analyze its main determinants. A transversal descriptive study of 738 patients with celiac disease was carried out. A series of questionnaires were answered related to their HRQoL, adherence to a gluten-free diet (GFD), and self-efficacy beliefs among other relevant variables. Regression analyses were carried out in order to explore the predictive variables in adherence to the GFD and HRQoL. A total of 61.2% showed a good HRQoL, and the main predictors of HRQoL were specific self-efficacy, adherence to the diet, risk perception, time since diagnosis, and age. While 68.7% of participants showed good or excellent adherence to the GFD, and the main predictors of adherence were specific self-efficacy, perceived adoption of recommended behaviors, HRQoL and gender. The HRQoL of patients with CD, and adherence to the GFD in Spain, are good. It is the self-efficacy expectation, measured specifically and not generally, which is the best predictor of both adherence and HRQoL. It is necessary to develop programs to improve the HRQoL of patients with CD that focus on improving specific self-efficacy

    Prevalence of celiac disease in primary care: the need for its own code

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    Background: Celiac disease (CD) is an autoimmune chronic enteropathy of the small intestine caused by exposure to gluten in genetically predisposed individuals. CD is not easy to diagnose due to its unspecific symptomatology, especially in adults, a diagnosed/undiagnosed ratio of 1:7 is estimated. CD does not have its own code in the International Classification of Primary Care (ICPC) but it is coded under code D99 “Disease digestive system, other”, which hinders diagnosis, intervention and research. The aim of this study is to investigate the prevalence of CD in Arago´n, Spain, using the information available from Primary Care, as well as to discuss the difficulties involved in determining prevalence of CD from data collected at this level of medical intervention. Methods: We designed an epidemiological cross-sectional study and analysed 26,964 electronic clinical records from the Aragonese Health Service under code ICPC D99 collected up to December 31st, 2016. The clinical records were classified by their editable field “descriptor” according to their probability of being related to CD. Analyses of gender, age, age at diagnosis, province and health sector were carried out. Results: We found 4534 clinical records under 293 different descriptors with a high probability of referring to CD. Prevalence in Arago´n was estimated to be 0.35% ranging from 0.24 to 0.81% with important differences among health sectors. Conclusions: The prevalence of 0.35% is a long way from the generally accepted 1% but within the usually considered ratio 1:7 of diagnosed:undiagnosed cases. Differences among sectors should be carefully analysed. Lacking its own ICPC code, diagnosis of CD in Primary Care Services is not included in a single category, but it is distributed under several descriptors, which makes it difficult to offer any firm diagnosis for treatment and hinders research. Finally, the high prevalence of CD justifies its own ICPC code and the need to withdraw CD from the generic D99 code “Disease digestive system other”

    Virtual self-conversation using motivational interviewing techniques to promote healthy eating and physical activity : A usability study

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    We aim to examine the usability of a Virtual Reality (VR) platform, called ConVRSelf, which has been designed to address the needs of People Living With Obesity (PLWO). Fourteen participants with a desire to eat healthier and exercise more (6 normal weight and 8 PLWO; Mean age = 41.86, SD = 13.89) were assigned to the experimental group (EG) or the control group (CG). EG participants, after being trained on motivational interviewing skills, engaged in a virtual self-conversation using embodiment and body swapping techniques, which aimed to normalize and resolve their ambivalence to change lifestyle habits. CG participants, embodied in their virtual bodies, participated in a pre-established discourse with a virtual counselor giving them psychoeducational advice about how to change lifestyle habits. A mixed-methods design was used, involving a semi-structured interview and self-report questionnaires, including readiness to change habits (Readiness Rulers), body ownership (Body Ownership Questionnaire, BOQ), and system usability (System Evaluation Questionnaire, SEQ). Thematic content analysis was carried out for qualitative data while statistical data analysis was carried out using SPSS 20.0. Participants from both groups showed high readiness to change lifestyle (Readiness Rulers) before engaging with the virtual experiences, which was maintained at the same level after the interventions and their scores on the SEQ and BOQ were satisfactory. Regarding qualitative information obtained from the interviews, almost all participants found the VR experience to be novel, interesting, and enjoyable. A higher acceptability was observed among PLWO from the EG than normal weight participants from the same group, a promising finding for the ConVRSelf platform, which had been specifically designed to address the needs of PLWO. The ConVRSelf system is well-accepted by participants and is ready to be tested with PLWO in a clinical setting

    A randomized phase II study of capecitabine-based chemoradiation with or without bevacizumab in resectable locally advanced rectal cancer: clinical and biological features

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    Background: perioperatory chemoradiotherapy (CRT) improves local control and survival in patients with locally advanced rectal cancer (LARC). The objective of the current study was to evaluate the addition of bevacizumab (BEV) to preoperative capecitabine (CAP)-based CRT in LARC, and to explore biomarkers for downstaging. Methods: patients (pts) were randomized to receive 5 weeks of radiotherapy 45 Gy/25 fractions with concurrent CAP 825 mg/m2 twice daily 5 days per week and BEV 5 mg/kg once every 2 weeks (3 doses) (arm A), or the same schedule without BEV (arm B). The primary end point was pathologic complete response (ypCR: ypT0N0). Results: ninety pts were included in arm A (44) or arm B (46). Grade 3-4 treatment-related toxicity rates were 16% and 13%, respectively. All patients but one (arm A) proceeded to surgery. The ypCR rate was 16% in arm A and 11% in arm B (p =0.54). Fifty-nine percent vs 39% of pts achieved T-downstaging (arm A vs arm B; p =0.04). Serial samples for biomarker analyses were obtained for 50 out of 90 randomized pts (arm A/B: 22/28). Plasma angiopoietin-2 (Ang-2) levels decreased in arm A and increased in arm B (p <0.05 at all time points). Decrease in Ang-2 levels from baseline to day 57 was significantly associated with tumor downstaging (p =0.02). Conclusions: the addition of BEV to CAP-based preoperative CRT has shown to be feasible in LARC. The association between decreasing Ang-2 levels and tumor downstaging should be further validated in customized studies

    Gasdermin B expression predicts poor clinical outcome in HER2-positive breast cancer

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    Altres ajuts: This work has been supported by the Community of Madrid (grant S2010/BMD-2303 to GMB), the Breast Cancer Research Foundation (BCRF) to JA. Alba Mota is a predoctoral student supported by a FPU fellowship (Spanish Ministry of Education, Culture and Sport). David Sarrio is a postdoctoral researcher funded by the AECC Scientific Foundation.Around, 30-40% of HER2-positive breast cancers do not show substantial clinical benefit from the targeted therapy and, thus, the mechanisms underlying resistance remain partially unknown. Interestingly, ERBB2 is frequently co-amplified and co-expressed with neighbour genes that may play a relevant role in this cancer subtype. Here, using an in silico analysis of data from 2,096 breast tumours, we reveal a significant correlation between Gasdermin B (GSDMB) gene (located 175 kilo bases distal from ERBB2) expression and the pathological and clinical parameters of poor prognosis in HER2-positive breast cancer. Next, the analysis of three independent cohorts (totalizing 286 tumours) showed that approximately 65% of the HER2-positive cases have GSDMB gene amplification and protein over-expression. Moreover, GSDMB expression was also linked to poor therapeutic responses in terms of lower relapse free survival and pathologic complete response as well as positive lymph node status and the development of distant metastasis under neoadjuvant and adjuvant treatment settings, respectively. Importantly, GSDMB expression promotes survival to trastuzumab in different HER2-positive breast carcinoma cells, and is associated with trastuzumab resistance phenotype in vivo in Patient Derived Xenografts. In summary, our data identifies the ERBB2 co-amplified and co-expressed gene GSDMB as a critical determinant of poor prognosis and therapeutic response in HER2-positive breast cancer
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