Modelos de flujo multifásico no isotermo y transporte reactivo multicomponente en medios porosos : 1. Formulación físico-matemática

[ES] El diseño y construcción de almacenamientos de residuos tóxicos en formaciones geológicas poco permeables requiere disponer de herramientas que permitan predecir el comportamiento a largo plazo del sistema. Por ello, es necesario el desarrollo de modelos numéricos para el estudio y predicción del comportamiento acoplado térmico, hidrodinámico, mecánico y geoquímico (THMG) tanto de la formación geológica como de los materiales arcillosos utilizados como barrera de ingeniería. En este artículo se presenta la formulación físico-matemática del flujo multifásico (agua, aire y otros gases), del transporte de un sistema multicomponente de solutos y las interacciones químicas en condiciones no isotermas. Esta formulación ha servido de base para la puesta a punto de un potente código de cálculo, FADES-CORE© (Juncosa, 1999; Juncosa y Navarro, 2000, Juncosa et al., 2001b), desarrollado en el marco de proyectos de investigación financiados por ENRESA en el contexto del almacenamiento geológico profundo de residuos radioactivos. En el segundo artículo esta serie de dos artículos (Juncosa et al., 2001a) se presenta el modelo numérico termo-hidro-geoquímico de un ensayo de laboratorio de hidratación y calentamiento realizado por CIEMAT para caracterizar las propiedades de contención y sellado de bentonitas compactadas. Aunque se ha desarrollado en el marco del almacenamiento de residuos radiactivos, la formulación matemática que se presenta así como su implementación numérica son aplicables al estudio de los procesos de flujo y transporte de solutos en la zona no saturada.Este trabajo se ha desarrollado dentro del Proyecto FEBEX financiado por ENRESA a través convenios de investigación con la Universidad de La Coruña (Proyecto FEBEX, códigos 703231 y 770045). El conjunto del Proyecto FEBEX ha recibido financiación de la Comisión Europea (Proyectos F14W-CT95-006 y FIKW-CT-2000-0016 del Programa de Fisión Nuclear). Una parte de los trabajos también ha sido realizado dentro del Proyecto CICYT HID98-282. La elaboración de la formulación física y matemática presentada en este trabajo ha sido posible gracias a las sugerencias recibidas del resto de los grupos participantes en el proyecto FEBEX (ENRESA, CIEMAT, CSIC-Zaidín, AITEMIN y las Universidades Politécnica de Cataluña y de Madrid) así como a Luis Montenegro y Ana Vázquez.Juncosa, R.; Samper Calvete, FJ.; Navarro, V.; Delgado Pin, J. (2002). Modelos de flujo multifásico no isotermo y transporte reactivo multicomponente en medios porosos : 1. Formulación físico-matemática. Ingeniería del Agua. 9(4):423-436. https://doi.org/10.4995/ia.2002.2625SWORD42343694ADENEKAN, A. E., PATZEK, T. W., PRUESS, K., (1993). Modeling of multiphase transport of multicomponent organic contaminants and heat in the subsurface: Numerical Formulation, Water Resour. Res., 29, 3727-3740.ANDERSON, G. M., CREAR. D. A., (1993). Thermodynamics in geochemistry. The equilibrium model. 566 pp. Ed. Oxford.APPELO, C. A. J., POSTMA, D., (1993). 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The Association of Malignancies with The Clinical Profile of Children with Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF-1) is a significant autosomal dominant disorder with a wide spectrum of clinical findings. These signs (Café au lait spots, bone dysplasia, Lisch nodules) usually start to emerge after the first months of life and most are benign in nature. On the other hand, neoplasms (optic glioma, neurofibroma, malignant peripheral nerve sheath tumor, soft tissue sarcoma, leukemia, breast cancer) are a major cause of morbidity and mortality in NF-1 patients. Cancer risk during the lifetime of an NF-1 patient is almost 10 times more than a person without NF-1, but what drives these patients into cancer is still unknown. This study aims to analyze the possible association of clinical findings with malignancies in children with NF-1. Medical records of 55 children with NF-1 who were followed up in a tertiary care pediatric oncology clinic between January 2005 and December 2014 were analyzed. We assessed clinical and demographic characteristics of patients, as well as the NF-1 diagnostic criteria, NF-1 related complications, and malignancies. The NF-1 patients without malignancy were classified in Group 1 while patients with malignancy were in Group 2. Logistic regression analysis was used to determine the risk factors of malignancy in NF-1. The mean age was 7.68 ± 4.65 years. Female sex was dominant in both groups. Café au lait spots were present in all patients. Axillary-inguinal freckling was observed in 76.4% of patients, followed by neurofibromas in 30.9%, Lisch nodules in 29.1%, bone dysplasia in 14.5%, optic gliomas in 23.6%, and a history of first degree relative with NF-1 in 63.6%. Central nervous system (CNS) tumors were present in 40%. Tumors other than CNS tumors were acute myeloid leukemia and schwannoma. None of the diagnostic criteria was a risk factor for predisposing to malignancy by itself. Having >3 criteria was found to be the risk factor for malignancy in NF-1 (OR:5.891, CI 95%: 1.676-20.705, p=0.006). There are no clearly defined risk factors predicting occurance of malignancies in NF-1 at present. However, we found a higher risk of malignancy association in patients who meet more than 3 diagnostic criteria of NF-1

Papillary microcarcinomas of the thyroid gland and immunohistochemical analysis of expression of p53 protein in papillary microcarcinomas

BACKGROUND: Thyroid papillary microcarcinoma (TPM) is defined according to WHO criteria as a thyroid tumor smaller than 1–1.5 cm. TPMs are encountered in 0.5–35.6 % of autopsies or surgical specimens where carcinoma had been unsuspected. The purpose of the present study was to evaluate patients who had TPMs in terms of clinical findings, histopathological features and immunohistochemical evidence of expression of the tumor suppressor gene p53. METHODS: A total of 44 patients with TPMs less than 1.0 cm in diameter were included in the study. The patients were evaluated clinically and the tumors were evaluated in terms of their histopathological and immunohistochemical features, including expression of p53. RESULTS: The female/male ratio was 2.8/1, and the median age at time of diagnosis was 49 years (range 20–71 years). The maximum diameter of the smallest focus was 0.1 mm, and that of the largest was 10 mm microscopically. The mean diameter of all tumors was 5.7 mm. There was no correlation between tumor size and age or gender. Of the TPMs, 72 % were found in the right lobe, 24 % in the left lobe and 4 % in the isthmus. Fine-needle aspiration biopsy provided the diagnosis of TPM in only 43.2 % of the patients. All patients were treated with surgery, with 20 undergoing conservative surgery, i.e. lobectomy or isthmusectomy, and 24 undergoing total thyroidectomy. Frozen section provided the diagnosis of TPM in only 56.8 % of the patients. We found lymphocytic thyroiditis in 13.6% of patients, follicular variants in 11.9%, capsular invasion in 26.8%, lymph node involvement in 11.9%, soft tissue metastases in the neck in 12.1% and multifocality in 31.7 %, and none of these were related to age or gender (p > 0.05). No distant metastases were observed during approximately 10 years of follow up. We found p53 positivity in 34.5 % of TPM tumors. However, p53 expression was not statistically related to age or gender. CONCLUSION: Our findings imply that TPMs may not be entirely innocent since they are associated with signs of poor prognosis such as capsular invasion, multifocal presentation, lymph node involvement and p53 positivity. Therefore, TPMs should be evaluated and followed like classical papillary cancers

Behavioural, emotional, and cognitive responses in European disasters: results of survivor interviews

In the European multi-centre study BeSeCu (Behaviour, Security, Culture), interviews were conducted in seven countries to explore survivors’ emotional, behavioural, and cognitive responses during disasters. Interviews, either in groups or one-to-one, were convened according to type of event: collapse of a building; earthquake; fire; flood; and terror attack. The content analysis of interviews resulted in a theoretical framework, describing the course of the events, behavioural responses, and the emotional and cognitive processing of survivors. While the environmental cues and the ability to recognise what was happening varied in different disasters, survivors’ responses tended to be more universal across events, and most often were adaptive and non-selfish. Several peri-traumatic factors related to current levels of post-traumatic stress were identified, while memory quantity did not differ as a function of event type or post-traumatic stress. Time since the event had a minor effect on recall. Based on the findings, several suggestions for emergency training are made

Ebullition of methane from peatlands: Does peat act as a signal shredder?

Bubbling (ebullition) of greenhouse gases, particularly methane, from peatlands has been attributed to environmental forcings, such as changes in atmospheric pressure. However, observations from peat soils suggest that ebullition and environmental forcing may not always be correlated and that interactions between bubbles and the peat structure may be the cause of such decoupling. To investigate this possibility, we used a simple computer model (Model of Ebullition and Gas storAge) to simulate methane ebullition from a model peat. We found that lower porosity peat can store methane bubbles for lengthy periods of time, effectively buffering or moderating ebullition so that it no longer reflects bubble production signals. Our results suggest that peat structure may act as a “signal shredder” and needs to be taken into account when measuring and modeling ebullition

The effect of sampling effort on estimates of methane ebullition from peat

We investigated the effect of sample size and sampling duration on methane bubble flux (ebullition) estimates from peat using a computer model. A field scale (10 m), seasonal (> 100 days) simulation of ebullition from a two-dimensional structurally-varying peat profile was modelled at fine spatial resolution (1 mm × 1 mm). The spatial and temporal scale of this simulation was possible because of the computational efficiency of the reduced complexity approach that was implemented, and patterns of simulated ebullition were consistent with those found in the field and laboratory. The simulated ebullition from the peat profile suggested that decreases in peat porosity – which cause increases in gas storage – produce ebullition that becomes increasingly patchy in space and erratic in time. By applying different amounts of spatial and temporal sampling effort it was possible to determine the uncertainty in ebullition estimates from the peatland. The results suggest that traditional methods to measure ebullition can equally overestimate and underestimate flux by 20% and large ebullition events can lead to large overestimations of flux when sampling effort is low. Our findings support those of field studies, and we recommend that ebullition should be measured frequently (hourly to daily) and at many locations (n > 14)

Social cognitive determinants of ecstasy use to target in evidence-based interventions: a meta-analytical review

Aims The health hazards and prevalence of ecstasy use have been documented in two decades of research, but no review reporting on potentially modifiable antecedents of use is available. The aim of this study was to integrate systematically research identifying cognitive correlates of ecstasy use. Such research has the potential to identify targets for evidence-based interventions designed to discourage use. Methods The databases PsycINFO and MedLine were searched, inclusion criteria applied to resulting hits, and descendency and ancestry approaches applied to the selected publications. Reported associations between cognitive determinants, including intention to use and ecstasy use measures, were synthesized by calculating a weighted mean effect size, r. Results The pattern of associations lent support both to the theory of planned behaviour (TPB) and the expectancy approach as descriptions of potentially useful determinants. Attitudes were associated most strongly with intention and use, followed by subjective norm and perceived behavioural control. Conclusions Consideration of the strength of associations and the potential modifiability of identified cognitions suggests that evidence-based interventions to discourage ecstasy use should target negative expectancies, perceived behavioural control and anticipated regret, and consider tailoring perceived behavioural control elements