Numerical Investigation on the Fixed-Stress Splitting Scheme for Biot’s Equations: Optimality of the Tuning Parameter

We study the numerical solution of the quasi-static linear Biot equations solved iteratively by the fixed-stress splitting scheme. In each iteration the mechanical and flow problems are decoupled, where the flow problem is solved by keeping an artificial mean stress fixed. This introduces a numerical tuning parameter which can be optimized. We investigate numerically the optimality of the parameter and compare our results with physically and mathematically motivated values from the literature, which commonly only depend on mechanical material parameters. We demonstrate, that the optimal value of the tuning parameter is also affected by the boundary conditions and material parameters associated to the fluid flow problem suggesting the need for the integration of those in further mathematical analyses optimizing the tuning parameter.acceptedVersio

Tamaño poblacional y alimentación de la nutria de río (lontra longicaudis annectens) en la Costa de Oaxaca, México

The neotropical river otter (Lontra longicaudis annectens) is threatened in Mexico, and in order to design sound conservation strategies for its conservation, basic studies on their biology and ecology are necessary. The diet and abundance were evaluated between July, 1999 and August, 2000 in the rivers Ayuta, Copalita and Zimatán in the coast of Oaxaca. We considered estimated of four otters in 147.5 km the river Ayuta. 86 otters in 330.75 km the rive Copalita and 177 otters in 228.85 km the river Zimatán.We found a relation in an indirect way between the abundance of the otter and dissolved O2. From 330 scats it was determined that they use four prey categories, which include crustaceans (53.0 ± 3.6%), fish (33.1 ± 9.9%), insects (9.8 ± 7.6%) and amphibians (4.0 ± 3.3%). In relation to the biomass ingested, the main prey were Macrobrachium americanum, M. acanthochirus and Gobiexos mexicanus. The largest number of fish and crustaceans used was obtained in the river Zimatán (n = 258 samples, 16 spp.) followed by the river Ayuta (n = 253, 14 spp) and the river Copalita (n = 197, 16 spp). We found a relation among the frequency of appearance of prey species in the scats, with their abundance (p < 0.01; r2 = 0.40), as well as a significant relation between the consumed biomass and the abundance of the prey. Abundance of prey is determined by O2 dissolved in the water (p = 0.04; r2 = 0.09) as well as turbidity (p = 0.04; r2 = 0.22). There was no relation between the physiochemical variables of the water with the diversity of the potential prey.La nutria de río neotropical (Lontra longicaudis annectens) se encuentra amenazada en México y para diseñar estrategias reales de conservación, son necesarios estudios básicos de su biología yecología. Se evaluaron la dieta y abundancia entre julio de 1999 y agosto del 2000 en los ríos Ayuta, Copalita y Zimatán en la costa de Oaxaca. Considerando una estimación de cuatro nutrias en 147.5 kmdel río Ayuta. 86 nutrias en 330.75 km del río Copalita y 177 nutrias en 228. 85 km del río Zimatán. Encontrando de forma indirecta una relación entre la abundancia de la nutria y el O2 disuelto en el agua.De 330 excretas se determinaron cuatro categorías de presa que incluyen crustáceos (53.0 ± 3.6%), peces (33.1 ± 9.9%), insectos (9.8 ± 7.6%) y anfibios (4.0 ± 3.3%). Respecto a la biomasa consumida, la presa principal fue Macrobrachium americanum, M. acanthochirus y Gobiexos mexicanus. El número más alto de peces y crustáceos se obtuvo en el río Zimatán (n = 258 muestras, 16 spp.) seguido por el río Ayuta (n = 253, 14 spp) y el río Copalita (n = 197, 16 spp). Encontrando una relación entre la frecuencia de aparición de especies de la presa en las excretas, con su abundancia (p < 0.01; r2 = 0.40), así como una relación significativa entre la biomasa consumida y la abundancia de las presas. La abundancia de las presas está determinada por O2 disuelto en el agua (p = 0.04; r2 = 0.09) así como la turbiedad (p = 0.04; r2 = 0.22). No hubo ninguna relación entre las variables fisicoquímicas del agua con la diversidad de las presas potenciales

Consumption experience, choice experience and the endowment effect

We report experiments investigating how experience influences the endowment effect. Our experiments feature endowments which are bundles of unfamiliar consumption goods. We examine how a subject’s willingness to swap items from their endowment is influenced by prior experiences of tasting the goods in question and by prior experiences of choosing between them. We do not find a statistically significant endowment effect in our baseline treatment and, because of this, we are unable to test for an effect of consumption experience. We do find an endowment effect when the endowment is acquired in two instalments and, in this setting, we find some evidence that choice experience increases trading. In a follow up experiment, we find evidence that the absence of an endowment effect in our baseline treatment is due to subjects being more willing to swap when they do not have to give up the last unit of their endowment

Health care utilization and mortality among elderly patients with myelodysplastic syndromes

Background: Mortality in patients with myelodysplastic syndromes (MDS) is high, and patients are likely to require hospitalizations, emergency department (ED) visits, and transfusions. The relationships between these events and the MDS complications of anemia, neutropenia, and thrombocytopenia are not well understood

Self evaluation of communication experiences after laryngeal cancer – A longitudinal questionnaire study in patients with laryngeal cancer

<p>Abstract</p> <p>Background</p> <p>Aim of this longitudinal study was to investigate the sensitivity to change of the Swedish Self Evaluation of Communication Experiences after Laryngeal Cancer questionnaire (the S-SECEL), addressing communication dysfunction in patients treated for laryngeal cancer. Previous studies have highlighted the need for more specific questionnaires for this purpose.</p> <p>Methods</p> <p>100 patients with Tis-T4 laryngeal cancer were included prior to treatment onset. Patients answered four questionnaires at six occasions during one year; the S-SECEL, the European Organisation for Research and Treatment of Cancer (EORTC) Core Quality of Life Core Questionnaire (QLQ-C30) supplemented by the Head and Neck cancer module (QLQ-H&N35) and the Hospital Anxiety and Depression (HAD) scale. In addition, performance status was assessed. Differences within groups were tested with the Wilcoxon paired signed ranks test and between-group analyses were carried out using the Mann-Whitney <it>U </it>test. Magnitude of group differences was analyzed by means of effect sizes.</p> <p>Results</p> <p>The S-SECEL was well accepted with a response rate of 76%. Communication dysfunction increased at 1 month, followed by a continuous decrease throughout the year. Changes were statistically significant at most measurement, demonstrating the sensitivity of the S-SECEL to changes in communication over time. The S-SECEL and the EORTC QLQ-C30 with the QLQ-H&N35 demonstrated similar results; however the S-SECEL was more sensitive regarding communication dysfunction. The largest changes were found in the most diagnose specific items concerning voice and speech.</p> <p>Conclusion</p> <p>The S-SECEL was investigated in the largest Scandinavian longitudinal study concerning health-related quality of life (HRQL) in laryngeal cancer patients. The questionnaire was responsive to change and showed convergent results when compared to established HRQL questionnaires. Our findings also indicate that the S-SECEL could be a more suitable instrument than the EORTC QLQ-C30 with QLQ-H&N35 when measuring communication experiences in patients with laryngeal cancer; it is more sensitive, shorter and can be used on an individual basis. As a routine screening instrument the S-SECEL could be a valuable tool for identifying patients at risk for psychosocial problems and to help plan rehabilitation. It is therefore recommended for clinical use in evaluation of communication dysfunction for all patients with laryngeal cancer irrespective of treatment.</p

Oral symptoms and functional outcome related to oral and oropharyngeal cancer

Purpose This study aimed to assess: (1) oral symptoms of patients treated for oral or oropharyngeal cancer; (2) how patients rank the burden of oral symptoms; (3) the impact of the tumor, the treatment, and oral symptoms on functional outcome. Methods Eighty-nine patients treated for oral or oropharyngeal cancer were asked about their oral symptoms related to mouth opening, dental status, oral sensory function, tongue mobility, salivary function, and pain. They were asked to rank these oral symptoms according to the degree of burden experienced. The Mandibular Function Impairment Questionnaire (MFIQ) was used to assess functional outcome. In a multivariate linear regression analyses, variables related to MFIQ scores (p a parts per thousand currency signaEuro parts per thousand 0.10) were entered as predictors with MFIQ score as the outcome. Results Lack of saliva (52%), restricted mouth opening (48%), and restricted tongue mobility (46%) were the most frequently reported oral symptoms. Lack of saliva was most frequently (32%) ranked as the most burdensome oral symptom. For radiated patients, an inability to wear a dental prosthesis, a T3 or T4 stage, and a higher age were predictive of MFIQ scores. For non-radiated patients, a restricted mouth opening, an inability to wear a dental prosthesis, restricted tongue mobility, and surgery of the mandible were predictive of MFIQ scores. Conclusions Lack of saliva was not only the most frequently reported oral symptom after treatment for oral or oropharyngeal cancer, but also the most burdensome. Functional outcome is strongly influenced by an inability to wear a dental prosthesis in both radiated and non-radiated patients

Evaluating the impact of new observational constraints on P-S/IVOC emissions, multi-generation oxidation, and chamber wall losses on SOA modeling for Los Angeles, CA

Secondary organic aerosol (SOA) is an important contributor to fine particulate matter (PM) mass in polluted regions, and its modeling remains poorly constrained. A box model is developed that uses recently published literature parameterizations and data sets to better constrain and evaluate the formation pathways and precursors of urban SOA during the CalNex 2010 campaign in Los Angeles. When using the measurements of intermediate-volatility organic compounds (IVOCs) reported in Zhao et al. (2014) and of semi-volatile organic compounds (SVOCs) reported in Worton et al. (2014) the model is biased high at longer photochemical ages, whereas at shorter photochemical ages it is biased low, if the yields for VOC oxidation are not updated. The parameterizations using an updated version of the yields, which takes into account the effect of gas-phase wall losses in environmental chambers, show model–measurement agreement at longer photochemical ages, even though some low bias at short photochemical ages still remains. Furthermore, the fossil and non-fossil carbon split of urban SOA simulated by the model is consistent with measurements at the Pasadena ground site. Multi-generation oxidation mechanisms are often employed in SOA models to increase the SOA yields derived from environmental chamber experiments in order to obtain better model–measurement agreement. However, there are many uncertainties associated with these aging mechanisms. Thus, SOA formation in the model is compared to data from an oxidation flow reactor (OFR) in order to constrain SOA formation at longer photochemical ages than observed in urban air. The model predicts similar SOA mass at short to moderate photochemical ages when the aging mechanisms or the updated version of the yields for VOC oxidation are implemented. The latter case has SOA formation rates that are more consistent with observations from the OFR though. Aging mechanisms may still play an important role in SOA chemistry, but the additional mass formed by functionalization reactions during aging would need to be offset by gas-phase fragmentation of SVOCs. All the model cases evaluated in this work show a large majority of the urban SOA (70–83 %) at Pasadena coming from the oxidation of primary SVOCs (P-SVOCs) and primary IVOCs (P-IVOCs). The importance of these two types of precursors is further supported by analyzing the percentage of SOA formed at long photochemical ages (1.5 days) as a function of the precursor rate constant. The P-SVOCs and P-IVOCs have rate constants that are similar to highly reactive VOCs that have been previously found to strongly correlate with SOA formation potential measured by the OFR. Finally, the volatility distribution of the total organic mass (gas and particle phase) in the model is compared against measurements. The total SVOC mass simulated is similar to the measurements, but there are important differences in the measured and modeled volatility distributions. A likely reason for the difference is the lack of particle-phase reactions in the model that can oligomerize and/or continue to oxidize organic compounds even after they partition to the particle phase

Threshold effect of foreign direct investment on environmental degradation

The aim of this paper is to investigate the threshold effect of foreign direct investment (FDI) on environmental degradation. In empirical analysis, FDI and environmental degradation are jointly determined under the given threshold variable and other exogenous variables. Using carbon dioxide (CO2) emissions per capita as a proxy for environmental degradation, the results show that increasing FDI worsens CO2 emissions after a threshold level of corruption has been reached. Our results demonstrate that increasing FDI will increase CO2 emissions when the degree of corruptibility is relatively high. The study suggests that further FDI and improved environmental quality are competing rather than compatible objectives in high-corruption countries and are compatible rather than competing objectives in low-corruption countries. Higher trade liberalization in low-corruption countries could contribute to negative environmental consequences because of the increased output or economic activity which results from increased trade. The robustness estimation confirms the evidence that pollution and economic development increase together up to a certain income level, after which the trend reverses.info:eu-repo/semantics/publishedVersio