Critical Josephson current through a bistable single-molecule junction

We compute the critical Josephson current through a single-molecule junction. As a model for a molecule with a bistable conformational degree of freedom, we study an interacting single-level quantum dot coupled to a two-level system and weakly connected to two superconducting electrodes. We perform a lowest-order perturbative calculation of the critical current and show that it can significantly change due to the two-level system. In particular, the \pi-junction behavior, generally present for strong interactions, can be completely suppressed.Comment: 7 pages, 5 figures; v2: minor changes, to be published in Phys. Rev.

Reintroduction of brook trout to the South River via Upwelling Springs

Populations of brook trout, Salvelinus fontinalis, throughout Virginia mountain streams have seen a rapid decline due to warmer conditions, decreased oxygen levels, and changes in the main stem streambed (Hudy et al., 2008). Current solutions have stocked more tolerant adult brook trout in the main stem rivers, which is costly and must be repeated yearly (Lennon, 1967). Finding an environment conducive for stocking brook trout eggs rather than adults would be ideal because they would return to this viable location to spawn, making them a self-sustaining population which is less costly and easier to implement. Upwelling springs connected to the main stem are potentially more conducive than the main stem due to lower temperatures, higher oxygenation, and less chemical runoff (Meehan, 1991). Brook trout eggs were reared in upwelling springs connected to the main stem of the South River in Waynesboro, Virginia in order to create an inexpensive self-sustained population. Percent survival, occurrence of deformities, conductivity, and temperature were measured at four experimental sites and compared to two control sites. One of the experimental sites, City Springs, was the most viable of the experimental springs as it had the highest survival and the lowest occurrence of deformities. Another experimental site, Baker Box, was the least viable as it had the lowest survival and conductivity and highest severity of deformities. Overall, all of the experimental sites proved to be favorable for the reintroduction of brook trout, with the exception of the Baker Box site. Future experiments should rear the eggs directly in the sediment to see if sediment size in the springs is more or less conducive than in the main stem

A testing program of machine shop practices for a cooperative industrial school

Thesis (Ed.M.)--Boston Universit

Translating Research to Practice for Children With Autism Spectrum Disorder: Part 2: Behavior Management in Home and Health Care Settings

Introduction Managing home and health care for children with autism spectrum disorder can be challenging because of the range of symptoms and behaviors exhibited. Method This article presents an overview of the emerging science related to the methods to foster family self-management of common concerns regarding activities of daily living and behaviors, as well as for the health care provider in primary and acute health care settings. Results Recommendations are provided to enhance the overall delivery of services, including understanding and managing a child\u27s challenging behaviors, and supporting family management of common activities of daily living and behaviors. Discussion Health care providers\u27 knowledge of evidence-based recommendations for providing care, supporting family self-management of common concerns, and referral heighten the likelihood of better outcomes for children with autism spectrum disorder

A testing program of machine shop practices for a cooperative industrial school

Thesis (Ed.M.)--Boston Universit

The Changing Situation of Labor Market Entrants in Germany: A Long-Run Analysis of Wages and Occupational Patterns

Concurrently with a steady increase of the supply of college educated workers, recent evidence for the U.S. indicated a decline in the demand for and the real wages of this group after 2000. We investigate empirically, whether there has been a similar trend in Germany. Based on comprehensive, long-run administrative data for the years 1975 to 2010, we use a set of employment indicators to analyze labor market patterns of job market entrants. Besides consideration of the developments of education attainment and wages over time, we put a particular focus on changes of the task composition, the chances of entering top-paying jobs, entry wages and wage growth, and skill premia over time. To allow for a detailed analysis, we distinguish four education groups. The empirical picture shows that since the year 2000 job entrants with higher education have experienced decreasing employment shares in top-paying positions. Moreover, starting wages and wage growth have both decreased, too. A reason for this has been the substitution of jobs that were formerly executed by lower qualifications. Our findings reveal similarities between Germany and the U.S. in terms of some declining fortunes of the young. However, whereas in the U.S. college educated workers have been affected, the results indicate that in Germany the medium-skilled and low-skilled have been particularly impaired

Advanced head and neck cancer: Long-term results of chemo-radiotherapy, complications and induction of second malignancies

Background: Chemo-radiotherapy is superior to radiotherapy alone in the treatment of advanced, inoperable head and neck cancer. The long-term treatment results, the induction of second malignant tumors, and other long-term toxicities are not well defined. Patients and Methods: 100 consecutive patients with advanced head and neck cancer who were treated at our center were studied. Treatment results, survival, the occurrence of late complications, and second malignant tumors (SMT) were investigated. 78 patients were treated with a protocol combining cisplatinum, 5-fluorouracil, folinic acid and hyper-fractionated irradiation. 22 patients were treated with other chemo-radiotherapy protocols. The relative risk of developing an SMT was compared with that within the normal population. Results: The cumulative total probability of survival was 51.1% at 2 years and 38.7% at 4 years. The probability of relapse-free survival was 39.9% at 2 years and 36.7% at 4 years. A total of 7 patients developed SMT (4 cases of lung cancer, 2 colon cancers, 1 skin cancer). After 6 years, a cumulative risk of SMT of 8.7% was observed. The relative risk of developing an SMT was significantly increased (4.45-fold in males) compared with a normal population. 13 of 38 evaluable patients (34.2%) had severe late complications like fibrosis of soft tissues, nerve lesions, or were dependent on tracheal cannulas. Conclusions: The treatment results and long-term prognoses in our population of unselected high-risk patients are unsatisfactory, but comparable to those from multicenter studies. About 35% of patients become long-term (> 4 years) survivors. SMT generally occur early, have a poor prognosis and, most likely, are not treatment-related. Approximately 30% of long-term survivors have severe, often incapacitating late effects. The treatment and - if possible - prevention of these late effects is important for the quality of life of patients who survived advanced head and neck cancer

Collisions of Slow Highly Charged Ions with Surfaces

Progress in the study of collisions of multiply charged ions with surfaces is reviewed with the help of a few recent examples. They range from fundamental quasi-one electron processes to highly complex ablation and material modification processes. Open questions and possible future directions will be discussed.Comment: 13 pages, 16 figures, review pape

Scattering theory of current-induced forces in mesoscopic systems

We develop a scattering theory of current-induced forces exerted by the conduction electrons of a general mesoscopic conductor on slow "mechanical" degrees of freedom. Our theory describes the current-induced forces both in and out of equilibrium in terms of the scattering matrix of the phase-coherent conductor. Under general nonequilibrium conditions, the resulting mechanical Langevin dynamics is subject to both non-conservative and velocity-dependent Lorentz-like forces, in addition to (possibly negative) friction. We illustrate our results with a two-mode model inspired by hydrogen molecules in a break junction which exhibits limit-cycle dynamics of the mechanical modes.Comment: 4+ pages, 1 figure; v2: minor modification