Photo-excited semiconductor superlattices as constrained excitable media: Motion of dipole domains and current self-oscillations

A model for charge transport in undoped, photo-excited semiconductor superlattices, which includes the dependence of the electron-hole recombination on the electric field and on the photo-excitation intensity through the field-dependent recombination coefficient, is proposed and analyzed. Under dc voltage bias and high photo-excitation intensities, there appear self-sustained oscillations of the current due to a repeated homogeneous nucleation of a number of charge dipole waves inside the superlattice. In contrast to the case of a constant recombination coefficient, nucleated dipole waves can split for a field-dependent recombination coefficient in two oppositely moving dipoles. The key for understanding these unusual properties is that these superlattices have a unique static electric-field domain. At the same time, their dynamical behavior is akin to the one of an extended excitable system: an appropriate finite disturbance of the unique stable fixed point may cause a large excursion in phase space before returning to the stable state and trigger pulses and wave trains. The voltage bias constraint causes new waves to be nucleated when old ones reach the contact.Comment: 19 pages, 8 figures, to appear in Phys. Rev.

What Matters Most to Patients and Rheumatologists? A Discrete Choice Experiment in Rheumatoid Arthritis

Introduction: To determine patient and rheumatologist preferences for rheumatoid arthritis (RA) treatment attributes in Spain and to evaluate their attitude towards shared decision-making (SDM). Methods: Observational, descriptive, exploratory and cross-sectional study based on a discrete choice experiment (DCE). To identify the attributes and their levels, a literature review and two focus groups (patients [P] = 5; rheumatologists [R] = 4) were undertaken. Seven attributes with 2–4 levels were presented in eight scenarios. Attribute utility and relative importance (RI) were assessed using a conditional logit model. Patient preferences for SDM were assessed using an ad hoc questionnaire. Results: Ninety rheumatologists [52.2% women; mean years of experience 18.1 (SD: 9.0); seeing an average of 24.4 RA patients/week (SD: 15.3)] and 137 RA patients [mean age: 47.5 years (SD: 10.7); 84.0% women; mean time since diagnosis of RA: 14.2 years (SD: 11.8) and time in treatment: 13.2 years (SD: 11.2), mean HAQ score 1.2 (SD: 0.7)] participated in the study. In terms of RI, rheumatologists and RA patients viewed: time with optimal QoL: R: 23.41%/P: 35.05%; substantial symptom improvement: R: 13.15%/P: 3.62%; time to onset of treatment action: R: 16.24%/P: 13.56%; severe adverse events: R: 10.89%/P: 11.20%; mild adverse events: R: 4.16%/P: 0.91%; mode of administration: R: 25.23%/P: 25.00%; and added cost: R: 6.93%/P: 10.66%. Nearly 73% of RA patients were involved in treatment decision-making to a greater or lesser extent; however, 27.4% did not participate at all. Conclusion: Both for rheumatologists and patients, the top three decision-making drivers are time with optimal quality, treatment mode of administration and time to onset of action, although in different ranking order. Patients were willing to be more involved in the treatment decision-making process

Rotura no traumática de componente cerámica-cerámica en PTC: presentación de un caso y revisión de la literatura.

Las fracturas de los componentes cerámicos empleados en artroplastia total de cadera (ATC) son infrecuentes. El objetivo de nuestro trabajo es presentar un caso de rotura precoz no traumática de componente ce - rámica-cerámica en ATC y revisar la literatura en relación con esta complicación. Se trata de un paciente de 58 años diagnosticado de necrosis avascular de cabeza femoral, fue intervenido mediante ATC, implantándosele un par cerámica-cerámica. A los 4 meses de la intervención, sin antecedente traumático previo, se observó fractura de la cúpula de cerámica de la prótesis. El paciente precisó de recambio protésico, utilizándose el par cerámica-polietileno. La fractura de los componentes del par cerámica- cerámica es poco frecuente. El fallo puede ser debido a un defecto de fabricación o en la colocación del implante. Los pacientes deben ser informados sobre la posibilidad de sufrir esta complicación antes de la implantación de una PTC con par cerámica-cerámica.Fractures of ceramic components used in total hip replacement (THR) are uncommon. To report a case of early non-traumatic rupture ceramic-ceramic component in THR and review the literature regarding this complication. A 58 years diagnosed with avascular necrosis of the femoral head, was operated by THR, a ceramic-on -ceramic. At 4 months after surgery, without previous trauma, fracture was observed ceramic dome of the prosthesis. The patient required replacement, using the ceramic-on-polyethylene. The fracture of ceramic components is rare. The failure may be due to a manufacturing defect or implant placement. Patients should be informed about the possi - bility of having this complication before implantation of a THR ceramic-on-ceramic

Rotifers from selected inland saline waters in the Chihuahuan Desert of México

© 2008 Walsh et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Enduro Campers

The Enduro Campers senior project team (Formerly known as Lobo Campers senior project team) was recruited by Mr. Leif Stein to assist in the design, manufacturing, and testing of the materials and components of his company’s expedition box camper. The two main focuses of the project, divided into two sub-teams, were on the testing and manufacturing process of the materials used in the camper, and on the design and analysis of the camper’s access door, step box, and other subsystems. The focus of the materials analysis and manufacturing team was based around the design parameter to use composite sandwich panels for the majority of the camper structure as set by Mr. Stein. This made the manufacturing and analysis of the camper much more complex than if a homogeneous material such as aluminum was used for the structure’s body. This increase in complexity is because composites are more difficult than homogenous materials to manufacture, test, and analyze. Because of this, the company needed a standardized physical testing procedure as well as an optimized bonding process for the sandwich materials. In order to choose the combination of materials for the sandwich panel construction, the project required a material analysis through physical testing and development of an FEA material model. The program ABAQUS was used to model the sandwich panel and can be applied to future analyses that Mr. Stein will need for larger, specific sections of the camper’s structure under different loading cases. The sub-component design & analysis team delivered a design for the door and step box of the camper that allows for maximum accessibility while maintaining the camper’s structural integrity while sealing the cabin from the elements. This design is also aesthetically pleasing, as these are the main visible components on the expedition box product. The design derived by our team was based on input from Mr. Stein, as well as the findings from the materials research team through analysis and physical testing. The manufacturing process of the step box was started and plans were handed to Mr. Stein for completion. This final design report goes over the project’s scope of work, concept design development, final design choices, manufacturing, design verification, project management, and the conclusions and recommendations the team has for Mr. Stein and his developing company. The report also includes recommendations for future analysis that can be helpful to better understanding the sandwich material used in the construction of the camper

Avaliação da eficácia do aluminosilicato de sódio hidratado na prevenção de câncer hepático induzido por aflatoxina em truta arco-íris

The use of aluminum silicates for decontaminating animal feed containing aflatoxins has yielded encouraging results in chicken and turkey poults. In contrast, very few studies have tested these substances in aquaculture. In this work, we investigated the efficacy of a trout diet containing 0.5% hydrated sodium aluminosilicate (HSAS) in protecting against contamination with aflatoxin B1. Trout were reared on these diets for one year and the experimental groups were examined monthly for hepatic presumptive preneoplastic and neoplastic lesions. Regardless of the presence of HSAS, all of the fish that received aflatoxin in their diet have shown hepatic lesions indicative of a carcinogenic process, presenting also the development of cancer in some fish. The concentration of HSAS used in this study was ineffective in preventing the onset of hepatic lesions induced by aflatoxin B1 in rainbow trout.Resultados encorajadores têm sido observados com o emprego de aluminosilicatos para descontaminação de ração contendo aflatoxina destinada à avicultura. No entanto, raros estudos têm sido destinados a testar essa substância em aqüicultura. Assim, no presente trabalho, foi investigada a eficácia do aluminosilicato de sódio hidratado (HSAS, 0,5%) em proteger a truta arco-íris dos danos hepáticos causados por ração contaminada com aflatoxina B1. Os grupos experimentais foram alimentados com suas respectivas dietas durante 12 meses, mensalmente cada grupo foi amostrado para análises anatomopatológica e histopatológica para verificação da presença de lesões hepáticas. Apesar da presença de HSAS, todos os grupos que receberam dieta contaminada com aflatoxina B1 apresentaram lesões hepáticas indicativas do processo carcinogênico, sendo que exemplares alimentados com essas dietas por mais longo prazo apresentaram hepatocarcinoma ou colangiocarcinoma. Estes resultados indicaram que a concentração de HSAS usada no presente estudo não foi efetiva em prevenir o desenvolvimento de lesões hepáticas induzidas por aflatoxina B1 em truta arco-íris.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundo de Apoio ao Ensino, Pesquisa e Extensão da Universidade Estadual de Campina

Amygdala involvement in self-blame regret

Regret-related brain activity is dependent on free choice, but it is unclear whether this activity is a function of more subtle differences in the degree of responsibility a decision-maker exerts over a regrettable outcome. In this experiment, we show that trial-by-trial subjective ratings of regret depend on a higher subjective sense of responsibility, as well as being dependent on objective responsibility. Using fMRI we show an enhanced amygdala response to regret-related outcomes when these outcomes are associated with high, as compared to low, responsibility. This enhanced response was maximal in participants who showed a greater level of enhancement in their subjective ratings of regret engendered by an objective increase in responsibility. Orbitofrontal and cingulate cortex showed opposite effects, with an enhanced response for regret-related outcomes when participants were not objectively responsible. The findings indicate that the way the brain processes regret-related outcomes depends on both objective and subjective aspects of responsibility, highlighting the critical importance of the amygdala

The impact of deep-sea fisheries and implementation of the UNGA Resolutions 61/105 and 64/72. Report of an international scientific workshop

The scientific workshop to review fisheries management, held in Lisbon in May 2011, brought together 22 scientists and fisheries experts from around the world to consider the United Nations General Assembly (UNGA) resolutions on high seas bottom fisheries: what progress has been made and what the outstanding issues are. This report summarises the workshop conclusions, identifying examples of good practice and making recommendations in areas where it was agreed that the current management measures fall short of their target

Time-related efficacy of liver cell isografts in fulminant hepatic failure

We and others have reported that dispersed liver cells transplanted into the spleen parenchyma of syngeneic rats remained functional and viable for a long time. This report describes our results with hepatocellular transplantation as a therapeutic method in a model of fulminant hepatic failure (FHF) in the rat. 60 male Sprague-Dawley rats weighing 200-250 g were used. The FHF was reached through an Eck's fistula with 2/3 hepatectomy at the same time. This model produced lethal hepatic failure in a highly reproducible manner. Liver cells were isolated by the collagenase method. 40 X 10(6) hepatocytes suspended in Hanks' balanced salt solution were transplanted into the spleen parenchyma 24 hr before (group 1), at the same time as (group 2), and 24 hr after (group 3) FHF was achieved. Additional sham-operated animals (groups 4 and 5) and a control group (group 6) were used. The hepatocellular transplantation markedly increased the survival of the animals with induced FHF to 80% (group 1) and 60% (group 2)--but not in group 3 (20%),--compared with 10% in the control group. This study shows that dispersed liver cells transplanted into the spleen can provide sufficient support to allow animals with lethal hepatic failure to survive and recover. Nevertheless the efficacy of transplantation is a time-related phenomenon with the FHF induction