First-principles analysis of spin-disorder resistivity of Fe and Ni

Spin-disorder resistivity of Fe and Ni and its temperature dependence are analyzed using noncollinear density functional calculations within the supercell method. Different models of thermal spin disorder are considered, including the mean-field approximation and the nearest-neighbor Heisenberg model. Spin-disorder resistivity is found to depend weakly on magnetic short-range order. If the local moments are kept frozen at their zero-temperature values, very good agreement with experiment is obtained for Fe, but for Ni the resistivity at elevated temperatures is significantly overestimated. Agreement with experiment for Fe is improved if the local moments are iterated to self-consistency. The overestimation of the resistivity for paramagnetic Ni is attributed to the reduction of the local moments down to 0.35 Bohr magnetons. Overall, the results suggest that low-energy spin fluctuations in Fe and Ni are better viewed as classical rotations of local moments rather than quantized spin fluctuations that would require an (S+1)/S correction.Comment: 10 pages (RevTeX), 6 eps figure

Calculations of spin-disorder resistivity from first principles

Spin-disorder resistivity of Fe and Ni is studied using the noncollinear density functional theory. The Landauer conductance is averaged over random disorder configurations and fitted to Ohm's law. The distribution function is approximated by the mean-field theory. The dependence of spin-disorder resistivity on magnetization in Fe is found to be in excellent agreement with the results for the isotropic s-d model. In the fully disordered state, spin-disorder resistivity for Fe is close to experiment, while for fcc Ni it exceeds the experimental value by a factor of 2.3. This result indicates strong magnetic short-range order in Ni at the Curie temperature.Comment: 3 pages, 3 figure

Nonequilibrium dynamics of mixtures of active and passive colloidal particles

We develop a mesoscopic field theory for the collective nonequilibrium dynamics of multicomponent mixtures of interacting active (i.e., motile) and passive (i.e., nonmotile) colloidal particles with isometric shape in two spatial dimensions. By a stability analysis of the field theory, we obtain equations for the spinodal that describes the onset of a motility-induced instability leading to cluster formation in such mixtures. The prediction for the spinodal is found to be in good agreement with particle-resolved computer simulations. Furthermore, we show that in active-passive mixtures the spinodal instability can be of two different types. One type is associated with a stationary bifurcation and occurs also in one-component active systems, whereas the other type is associated with a Hopf bifurcation and can occur only in active-passive mixtures. Remarkably, the Hopf bifurcation leads to moving clusters. This explains recent results from simulations of active-passive particle mixtures, where moving clusters and interfaces that are not seen in the corresponding one-component systems have been observed.Comment: 17 pages, 3 figure

PHENIX first measurement of the J/psi elliptic flow parameter v2 in Au+Au collisions at sqrt(sNN) = 200 GeV

Recent results indicate that the J/psi suppression pattern differs with rapidity showing a larger suppression at forward rapidity. J/psi suppression mechanisms based on energy density (such as color screening, interaction with co-movers, etc.) predict the opposite trend. On the other hand, it is expected that more c\bar{c} pairs should be available to form quarkonia at mid-rapidity via recombination. Some models provide a way to differentiate J/psi production from initially produced c\bar{c} pairs and final state recombination of uncorrelated pairs, via the rapidity and transverse momentum dependence of the elliptic flow (v2). During 2007 data taking at RHIC, a large sample of Au+Au collisions at sqrt(sNN)=200 GeV was collected. The statistics has been increased compared to previous 2004 data set, thus allowing a more precise measurement of the J/psi production at both mid and forward rapidity. Furthermore, the PHENIX experiment benefited from the addition of a new detector, which improves the reaction plane resolution and allows us to measure the J/psi v2. Comparing this measurement to the positive D-mesons v2 (through non-photonic electron decays) will help constraining the J/psi production mechanisms and getting a more precise picture of the proportion of J/psi coming from direct production or charm quark coalescence. Details on how the J/psi v2 is measured at both rapidities are presented. The J/psi v2 as a function of transverse momentum are compared to existing models.Comment: 4 pages, 3 figures, Quark Matter 2008 proceeding

Variation in treatment modalities, costs and outcomes of rectal cancer patients in Poland

Aim of the study: To evaluate outcome, costs and treatment differences in rectal cancer patients between various regions in Poland. Material and methods: Data from the Polish National Health Fund of all patients with rectal cancer diagnosed and treated between 2005 and 2007 were analyzed. Overall, relative 5-year survival and the percentage of patients receiving chemotherapy, radiotherapy and surgery were analyzed. The possible influence of cost of treatment per patient and mean number of rectal cancer patients per surgical oncologist were analyzed as well. Results: In total 15,281 patients with rectal cancer were diagnosed and treated in Poland in 2005–2007 within the services of the National Health Fund. The overall, relative 5-year survival rate was 51.6%. Curative surgery was performed in 64.1% of patients. Radiotherapy and chemotherapy were used in 47.5% and 60.7% of patients, respectively. The mean cost of treatment of one rectal cancer patient was 32,800 PLN and there were 49.8 rectal cancer patients per specialist in surgical oncology. Important differences between regions were found in all these factors, but without a significant influence on survival. A correlation between numbers of patients per specialist in different voivodeships and survival rates was observed, as well as a correlation between percentage of surgical resection in voivodeships and survival rates (p = 0.07). Conclusions: Results of treatment of colorectal cancer in Poland improved significantly during the last decade. There exist however, important disparities between regions in terms of method of treatment, costs and outcomes

Total number of lymph nodes and numer of metastatic lymph nodes harvested during radical mastectomy did not influence early postoperative drainage volume

Objectives: We aimed at evaluation of the influence of the extent of axillary lymph node dissection, measured by the total number of lymph nodes harvested, on the drainage volume. We also looked at the lymph node positivity (N+) and the number of metastatic axillary lymph nodes as a potential prognostic factors in this regard. Material and methods: We have analysed the data of 63 patients (F/M: 62/1) with breast cancer, who underwent radical modified mastectomy in 2008-2009 in the single department of surgical oncology. Results: We observed no significant correlation between the 1) total number of axillary lymph nodes harvested during lymphadenectomy, 2) presence of metastatic lymph nodes (node positive disease), 3) number of metastatic axillary lymph nodes and: drainage volume on the day of surgery, drainage volume on three consecutive postoperative days and drainage volume from the day of surgery to drain removal. Conclusion: The extent of axillary lymph node dissection, measured by the total number of lymph nodes excised, did not influence drainage volume after radical modified mastectomy. Neither total number of metastatic lymph nodes excised nor the node positivity (N+) were associated with increased drainage volume after mastectomy with axillary dissection

Obstructive hydrocephalus and intracerebral mass secondary to Epicoccum nigrum

Here we report a case of a 14-week-old girl with a history of intrauterine drug exposure and hypoxic ischemic encephalopathy secondary to cardiac arrest requiring prolonged resuscitation at birth presented with irritability and a bulging anterior fontanelle. After neurosurgical resection, pathologic examination showed fungal hyphae, an