Magnetism and Superconductivity in (RE)Ni2B2C: The Case of TmNi2B2C

The recently reported coexistence of an oscillatory magnetic order with the wave vector Q=0.241 \AA^{-1} and superconductivity in TmNi2B2C is analyzed theoretically. It is shown that the oscillatory magnetic order and superconductivity interact predominantly via the exchange interaction between localized moments (LM's) and conduction electrons, while the electromagnetic interaction between them is negligible. In the coexistence phase of the clean TmNi2B2C the quasiparticle spectrum should have a line of zeros at the Fermi surface, giving rise to the power law behavior of thermodynamic and transport properties. Two scenarios of the origin of the oscillatory magnetic order in TmNi2B2C are analyzed: a) due to superconductivity and b) independently on superconductivity. Experiments in magnetic field are proposed in order to choose between them.Comment: 12 pages with 2 PS figures, RevTe

Learning Mazes with Aliasing States: An LCS Algorithm with Associative Perception

Learning classifier systems (LCSs) belong to a class of algorithms based on the principle of self-organization and have frequently been applied to the task of solving mazes, an important type of reinforcement learning (RL) problem. Maze problems represent a simplified virtual model of real environments that can be used for developing core algorithms of many real-world applications related to the problem of navigation. However, the best achievements of LCSs in maze problems are still mostly bounded to non-aliasing environments, while LCS complexity seems to obstruct a proper analysis of the reasons of failure. We construct a new LCS agent that has a simpler and more transparent performance mechanism, but that can still solve mazes better than existing algorithms. We use the structure of a predictive LCS model, strip out the evolutionary mechanism, simplify the reinforcement learning procedure and equip the agent with the ability of associative perception, adopted from psychology. To improve our understanding of the nature and structure of maze environments, we analyze mazes used in research for the last two decades, introduce a set of maze complexity characteristics, and develop a set of new maze environments. We then run our new LCS with associative perception through the old and new aliasing mazes, which represent partially observable Markov decision problems (POMDP) and demonstrate that it performs at least as well as, and in some cases better than, other published systems

Could Active Perception Aid Navigation of Partially Observable Grid Worlds?

Due to the unavoidable fact that a robot's sensors will be limited in some manner, it is entirely possible that it can find itself unable to distinguish between di#ering states of the world (the world is in e#ect partially observable). If reinforcement learning is used to train the robot, then this confounding of states can have a serious e#ect on its ability to learn optimal and stable policies. Good results have been achieved by enhancing reinforcement learning algorithms through the addition of memory or the use of internal models. In our work we take a di#erent approach and consider whether active perception could be used instead

The place of imagination in ELT teacher education

In this workshop participants will be invited to engage with metaphors and fictional narratives and to discuss their potential role in ELT teacher education. It will also briefly examine the place of imagination in western thinking, its reflections in ELT teaching models and approaches, and the interplay between imagination, construction of knowledge, reflection and educational change

Global mycorrhizal plant distribution linked to terrestrial carbon stocks

Vegetation impacts on ecosystem functioning are mediated by mycorrhizas, plant–fungal associations formed by most plant species. Ecosystems dominated by distinct mycorrhizal types differ strongly in their biogeochemistry. Quantitative analyses of mycorrhizal impacts on ecosystem functioning are hindered by the scarcity of information on mycorrhizal distributions. Here we present global, high-resolution maps of vegetation biomass distribution by dominant mycorrhizal associations. Arbuscular, ectomycorrhizal, and ericoid mycorrhizal vegetation store, respectively, 241 ± 15, 100 ± 17, and 7 ± 1.8 GT carbon in aboveground biomass, whereas non-mycorrhizal vegetation stores 29 ± 5.5 GT carbon. Soil carbon stocks in both topsoil and subsoil are positively related to the community-level biomass fraction of ectomycorrhizal plants, though the strength of this relationship varies across biomes. We show that human-induced transformations of Earth’s ecosystems have reduced ectomycorrhizal vegetation, with potential ramifications to terrestrial carbon stocks. Our work provides a benchmark for spatially explicit and globally quantitative assessments of mycorrhizal impacts on ecosystem functioning and biogeochemical cycling.Environmental Biolog

Predictive ability of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system following infrapopliteal endovascular interventions for critical limb ischemia

Objective The Society for Vascular Surgery (SVS) Lower Extremity Guidelines Committee has composed a new threatened lower extremity classification system that reflects the three major factors that impact amputation risk and clinical management: Wound, Ischemia, and foot Infection (WIfI). Our goal was to evaluate the predictive ability of this scale following any infrapopliteal endovascular intervention for critical limb ischemia (CLI). Methods From 2004 to 2014, a single institution, retrospective chart review was performed at the Beth Israel Deaconess Medical Center for all patients undergoing an infrapopliteal angioplasty for CLI. Throughout these years, 673 limbs underwent an infrapopliteal endovascular intervention for tissue loss (77%), rest pain (13%), stenosis of a previously treated vessel (5%), acute limb ischemia (3%), or claudication (2%). Limbs missing a grade in any WIfI component were excluded. Limbs were stratified into clinical stages 1 to 4 based on the SVS WIfI classification for 1-year amputation risk, as well as a novel WIfI composite score from 0 to 9. Outcomes included patient functional capacity, living status, wound healing, major amputation, major adverse limb events, reintervention, major amputation, or stenosis (RAS) events (> ×3.5 step-up by duplex), amputation-free survival, and mortality. Predictors were identified using Kaplan-Meier survival estimates and Cox regression models. Results Of the 596 limbs with CLI, 551 were classified in all three WIfI domains on a scale of 0 (least severe) to 3 (most severe). Of these 551, 84% were treated for tissue loss and 16% for rest pain. A Cox regression model illustrated that an increase in clinical stage increases the rate of major amputation (hazard ratio [HR], 1.6; 95% confidence interval [CI], 1.1-2.3). Separate regression models showed that a one-unit increase in the WIfI composite score is associated with a decrease in wound healing (HR, 1.2; 95% CI, 1.1-1.4) and an increase in the rate of RAS events (HR, 1.2; 95% CI, 1.1-1.4) and major amputations (HR, 1.4; 95% CI, 1.2-1.8). Conclusions This study supports the ability of the SVS WIfI classification system to predict 1-year amputation, RAS events, and wound healing in patients with CLI undergoing endovascular infrapopliteal revascularization procedures

The perioperative effect of concomitant procedures during open infrarenal abdominal aortic aneurysm repair

Background: Open repair of abdominal aortic aneurysms (AAAs) is occasionally performed in conjunction with additional procedures; however, how these concomitant procedures affect outcome is unclear. This study determined the frequency of additional procedures during elective open AAA repair and the effect on perioperative outcomes. Methods: All elective infrarenal open AAA repairs between January 2003 and November 2014 in the Vascular Study Group of New England (VSGNE) were identified. Patients were grouped by concomitant procedures, which included no concomitant procedure, renal artery bypass, lower extremity bypass, other abdominal procedure, or thromboembolectomy. Analyses were performed using multivariable logistic regression. Results: Of 1314 patients who underwent elective AAA repair, 153 (11.6%) had a concomitant procedure, including renal bypass in 27 (2.1%), lower extremity bypass in 28 (2.1%), other abdominal procedures in 64 (4.9%), and thromboembolectomy in 48 (3.7%). Independent risk factors for 30-day mortality were renal bypass (odds ratio [OR], 7.2; 95% confidence interval [CI], 1.9-27.7), other abdominal procedures (OR, 4.8; 95% CI, 1.6-14.1), and thromboembolectomy (OR, 8.8; 95% CI, 3.1-24.9). Deterioration of renal function was predicted by renal bypass (OR, 5.1; 95% CI, 2.1-12.4) and thromboembolectomy (OR, 3.7; 95% CI, 1.8-7.6). Lower extremity bypass and thromboembolectomy were predictive of postoperative leg ischemia (OR, 8.9; 95% CI, 2.7-29.0; OR, 11.2; 95% CI, 4.4-28.8, respectively), and thromboembolectomy was also predictive of postoperative bowel ischemia (OR, 4.4; 95% CI, 1.6-12.0). Conclusions: Performing additional procedures during infrarenal open AAA repair is associated with increased morbidity and mortality in the postoperative period. Careful deliberation of the operative risks and the necessity of the additional interventions are therefore advised during operative planning. This study also highlights the importance of avoiding perioperative thromboembolic events

Progesterone receptor membrane component 1 deficiency attenuates growth while promoting chemosensitivity of human endometrial xenograft tumors

Endometrial cancer is the leading gynecologic cancer in women in the United States with 52,630 women predicted to be diagnosed with the disease in 2014. The objective of this study was to determine if progesterone (P4) receptor membrane component 1 (PGRMC1) influenced endometrial cancer cell viability in response to chemotherapy in vitro and in vivo. A lentiviral-based shRNA knockdown approach was used to generate stable PGRMC1-intact and PGRMC1-deplete Ishikawa endometrial cancer cell lines that also lacked expression of the classical progesterone receptor (PGR). Progesterone treatment inhibited mitosis of PGRMC1-intact, but not PGRMC1-deplete cells, suggesting that PGRMC1 mediates the anti-mitotic actions of P4. To test the hypothesis that PGRMC1 attenuates chemotherapy-induced apoptosis, PGRMC1-intact and PGRMC1-deplete cells were treated in vitro with vehicle, P4 (1 μM), doxorubicin (Dox, 2 μg/ml), or P4 + Dox for 48 h. Doxorubicin treatment of PGRMC1-intact cells resulted in a significant increase in cell death; however, co-treatment with P4 significantly attenuated Dox-induced cell death. This response to P4 was lost in PGRMC1-deplete cells. To extend these observations in vivo, a xenograft model was employed where PGRMC1-intact and PGRMC1-deplete endometrial tumors were generated following subcutaneous and intraperitoneal inoculation of immunocompromised NOD/SCID and nude mice, respectively. Tumors derived from PGRMC1-deplete cells grew slower than tumors from PGRMC1-intact cells. Mice harboring endometrial tumors were then given three treatments of vehicle (1:1 cremophor EL: ethanol + 0.9% saline) or chemotherapy [Paclitaxel (15 mg/kg, i.p.) followed after an interval of 30 minutes by CARBOplatin (50 mg/kg)] at five day intervals. In response to chemotherapy, tumor volume decreased approximately four-fold more in PGRMC1-deplete tumors when compared with PGRMC1-intact control tumors, suggesting that PGRMC1 promotes tumor cell viability during chemotherapeutic stress. In sum, these in vitro and in vivo findings demonstrate that PGRMC1 plays a prominent role in the growth and chemoresistance of human endometrial tumors