Consciousness and the Wigner's friend problem

It is generally agreed that decoherence theory is, if not a complete answer, at least a great step forward towards a solution of the quantum measurement problem. It is shown here however that in the cases in which a sentient being is explicitly assumed to take cognizance of the outcome the reasons we have for judging this way are not totally consistent, so that the question has to be considered anew. It is pointed out that the way the Broglie-Bohm model solves the riddle suggests a possible clue, consisting in assuming that even very simple systems may have some sort of a proto-consciousness, but that their ``internal states of consciousness'' are not predictive. It is, next, easily shown that if we imagine the systems get larger, in virtue of decoherence their internal states of consciousness progressively gain in predictive value. So that, for macro-systems, they may be identified (in practice) with the predictive states of consciousness on which we ground our observational predictions. The possibilities of carrying over this idea to standard quantum mechanics are then investigated. Conditions of conceptual consistency are considered and found rather strict, and, finally, two solutions emerge, differing conceptually very much from one another but in both of which the, possibly non-predictive, generalized internal states of consciousness play a crucial role

Elastic Correlations in Nucleosomal DNA Structure

The structure of DNA in the nucleosome core particle is studied using an elastic model that incorporates anisotropy in the bending energetics and twist-bend coupling. Using the experimentally determined structure of nucleosomal DNA [T.J. Richmond and C.A. Davey, Nature {\bf 423}, 145 (2003)], it is shown that elastic correlations exist between twist, roll, tilt, and stretching of DNA, as well as the distance between phosphate groups. The twist-bend coupling term is shown to be able to capture these correlations to a large extent, and a fit to the experimental data yields a new estimate of G=25 nm for the value of the twist-bend coupling constant

Is TNF-α a prognostic factor in patients with sepsis?

Objective: To determine tumor necrosis factor-α (TNF-α) levels in a prospective study in 58 hospitalized patients in a department of internal medicine (63 episodes, 29 in immunocompromised patients) during a 7-month period.Methods: Patients fulfilling the following criteria were included: clinical evidence of acute infection, temperature >38.2°C, tachycardia >90 beats/min, tachypnea >20 breaths/min. Samples were taken from day 1 up to day 13 after an infection was diagnosed, and TNF-α was determined by enzyme immunoassay.Results: In 29 episodes (46.0%) the infection was microbiologically documented. The median of the TNF-α levels in the Gram-negative episodes was significantly higher than that in the Gram-positive episodes (p = 0.002). Thirteen of 63 episodes (20.6%) had a fatal outcome. With respect to all measured values, the non-survivors had a significantly higher median of TNF-α levels than the survivors (p = 0.0001). There was, however, great interpatient and intrapatient variability in TNF-α levels; thus, no unequivocal correlation between TNF-α and outcome could be documented.Conclusions: Our data indicate that the influence of the infecting organism on TNF-α kinetics is less pronounced than that of the underlying disease

Predicting polydisperse granular segregation

Most granular materials in industrial applications and natural settings are size-polydisperse, but most models and simulations of segregation consider only bidisperse particle distributions. Here, we extend our recently developed theoretical advection–diffusion–segregation model to polydisperse particle distributions. To test the theoretical approach, we model and simulate grains log-normally distributed by size in a chute flow. In steady state, material near the free surface is dominated by large particles, whereas the lower regions are composed of mostly small particles. The segregation pattern depends on a single dimensionless control parameter, which is a function of the particle sizes, the diffusion coefficient, the shear rate, and the flowing layer depth. Interestingly, for all values of the control parameter, the overall log normal particle size distribution is approximately maintained at each spatial location, but with different mean and variance than the overall particle distribution. To confirm the theoretical results, we use discrete element method (DEM) simulations using a general purpose graphics processing unit. Quantitative agreement is found between theory and DEM simulations. Funded by the Dow Chemical Company

Aspectos sociais do sistema produtivo de propriedades da pecuária de corte familiar na metade Sul do Rio Grande do Sul.

O objetivo deste trabalho foi caracterizar e apreender a realidade de pecuaristas familiares, em três localidades situadas na metade sul do RS: Cerro da Jaguatirica, no município de Manoel Viana; Santa Barbinha em Caçapava do Sul, e Palmas em Bagé. O diagnóstico envolveu entrevistas utilizando um questionário semi-estruturado em 30 unidades produtivas, abrangendo um total de 110 pessoas, e reuniões participativas dos técnicos da Embrapa Pecuária Sul, Emater/RS e os produtores. Esse diagnóstico teve foco em características sociais e do sistema produtivo, abrangendo um conjunto de informações essenciais para o entendimento das lógicas de produção e sobrevivência dessas famílias.bitstream/item/33159/1/BP-35.pd