Interference in interacting quantum dots with spin

We study spectral and transport properties of interacting quantum dots with spin. Two particular model systems are investigated: Lateral multilevel and two parallel quantum dots. In both cases different paths through the system can give rise to interference. We demonstrate that this strengthens the multilevel Kondo effect for which a simple two-stage mechanism is proposed. In parallel dots we show under which conditions the peak of an interference-induced orbital Kondo effect can be split.Comment: 8 pages, 8 figure

The Depth and Breadth of Google Scholar: An Empirical Study

The introduction of Google Scholar in November 2004 was accompanied by fanfare, skepticism, and numerous questions about the scope and coverage of this database. Nearly one year after its inception, many of these questions remain unanswered. This study compares the contents of 47 different databases with that of Google Scholar. Included in this investigation are tests for Google Scholar publication date and publication language bias, as well as a study of upload frequency. Tests show Google Scholar’s current strengths to be coverage of science and medical databases, open access databases, and single publisher databases. Current weaknesses include lack of coverage of social science and humanities databases and an English language bias

High efficiency deterministic Josephson Vortex Ratchet

We investigate experimentally a Josephson vortex ratchet -- a fluxon in an asymmetric periodic potential driven by a deterministic force with zero time average. The highly asymmetric periodic potential is created in an underdamped annular long Josephson junction by means of a current injector providing efficiency of the device up to 91%. We measured the ratchet effect for driving forces with different spectral content. For monochromatic high-frequency drive the rectified voltage becomes quantized. At high driving frequencies we also observe chaos, sub-harmonic dynamics and voltage reversal due to the inertial mass of a fluxon.Comment: accepted by PRL. To see status click on http://134.2.74.170:88/cnt/cond-mat_0506754.htm

The use of finite-element software to solve hygrothermal builiding physical problems related to insultating high rise buildings facades

In The Netherlands high rise buildings from 1960 and before were hardly insulated. To improve the thermal performance of the buildings the facades may be insulated afterwards. The energy loss will be reduced and thermal comfort will be improved by higher indoor surface temperatures. Problems however may be introduced by thermal bridge effects of anchors, floors and indoor walls. Further more the outer facade surface will be colder during winter time. Frost damage and internal condensation may be the deleterious building physical effects. The purpose of the work is to prevent damages which may result from insulating retrofitting of building facades. For this kind of building physical problems specific software has been developed and is in use all over the world. The coupling of heat, air and moisture (HAM) transport, however, has not been solved most of the times. An attempt has been made to solve this kind of coupled problems by the use of COMSOL (Comsol 2006). As an example of this kind of coupled problems the thermal bridge effect of an anchor in an uninsulated and afterwards insulated facade of a high rise building has been examined. The air flow calculation in the cavity was coupled to the thermal and hygric diffusion process. The results of the separately uncoupled COMSOL simulations (like thermal bridge calculations) were compared with results from third party software and the coupled simulation results were compared with infrared thermographs. The conclusion of the paper is that the use of COMSOL in this kind of problems may solve the problem of coupled building physical effects in building constructions

Efficacy of oral citrate administration in primary hyperoxaluria

Urinary citrate is a potent inhibitor of calcium oxalate (CaOx) crystallization, but oral citrate has rarely been used in patients with primary hyperoxaluria (PH). We studied the effect of sodium citrate administration (0.1-0.15 g/kg/day) on urinary citrate excretion and CaOx saturation in seven paediatric patients and the clinical response to long-term treatment (average 4 years) in five patients. Urinary citrate increased from 0.73 to 2.54 mmol/24h/l.73 m2 and urinary saturation for CaOx (calculated by equil 2) decreased from 11.41 to 6.79 (for both, p<0.02). Long-term administration of alkali citrate [0.15 g (0.5 mmol)/kg/day] resulted in stable or improved renal function in three and slow deterioration in two partially non-compliant patients. Alkali citrate is effective in patients with P

Non-ideal artificial phase discontinuity in long Josephson 0-kappa-junctions

We investigate the creation of an arbitrary $\kappa$-discontinuity of the Josephson phase in a long Nb-AlO_x-Nb Josephson junction (LJJ) using a pair of tiny current injectors, and study the formation of fractional vortices formed at this discontinuity. The current I_inj, flowing from one injector to the other, creates a phase discontinuity kappa ~ I_inj. The calibration of injectors is discussed in detail. The small but finite size of injectors leads to some deviations of the properties of such a 0-kappa-LJJ from the properties of a LJJ with an ideal kappa-discontinuity. These experimentally observed deviations in the dependence of the critical current on I_inj$ and magnetic field can be well reproduced by numerical simulation assuming a finite injector size. The physical origin of these deviations is discussed.Comment: Submitted to Phys. Rev. B (12 figures). v 2: refs updated, long eqs fixed v 3: major changes, fractional vortex dynamics exclude

Synthesis for Polynomial Lasso Programs

We present a method for the synthesis of polynomial lasso programs. These programs consist of a program stem, a set of transitions, and an exit condition, all in the form of algebraic assertions (conjunctions of polynomial equalities). Central to this approach is the discovery of non-linear (algebraic) loop invariants. We extend Sankaranarayanan, Sipma, and Manna's template-based approach and prove a completeness criterion. We perform program synthesis by generating a constraint whose solution is a synthesized program together with a loop invariant that proves the program's correctness. This constraint is non-linear and is passed to an SMT solver. Moreover, we can enforce the termination of the synthesized program with the support of test cases.Comment: Paper at VMCAI'14, including appendi

Education in Modern China a Case Study: Teachers\u27 Attitudes of In-service / Professional Development in Guangzhou, China

China has a long history of education, which can be traced back to the Shang Dynasty (1523 B.C. to 1027 B.C.). During this long history changes occurred as the needs of society changed. During the Warring States Period (770 B.C. to 221 B.C.), the philosophies of Daoism and Confucianism were developed. These philosophies became the cornerstone of education theory and practice in China. At the end of the Qing Dynasty (1644 to 1911), steps were taken to train teachers with the goal of universal education for all of its citizens. Since 1977, the Chinese government has taken strides in universal education one way they are working on this is by improving teacher professional development. This study examined the attitudes of teachers in the city of Guangzhou China as to their attitudes toward professional development. Using employment records, every third teacher was asked if they were willing to participate in the study. If so they were given the internet site to take the survey in the school. There were a total of 464 teachers who agreed to take part in the study. After teachers finished taking the study and the answers were examined, it was found that question 24 was not answered 150 times; further examination into this revealed that the question might have had a cultural bias indicting the teacher wanted to advance and take the supervisor\u27s position. The instrument used was Attitude Toward In-service Scale by Flanagan-Hudson, with a Likert scale ranging from 1 (Strongly Disagree) to 5 (Strongly Agree). The following statistical analyses were performed on the data: a one-way ANOVA, a two-way ANOVA, Tukey test, and a Brown and Forsythe\u27s Test for homogeneity of total variance. The study indicated that there was no significant difference in attitudes of teachers based on gender. Teachers in the male category rated themselves a mean of 3.76 and a standard deviation of 0.45. Teachers in the female category rated themselves 4.03 and a standard deviation of 0.38. The study indicated that there was a significant difference in the attitudes of teachers toward professional development based on the years of experience. Teachers with more years of experience rated themselves higher on the scale. Teachers of the 5 years or less and the 6 to 15 years categories had means of 3.38 and 3.98 respectively and a standard deviation of 0.55. Teachers in the 16 to 25 years and 26 years or more categories had a means of 4.06 and a standard deviation of 0.21 and 0.22 respectively. The study indicated that there were significant differences in the attitude of teachers towards professional development based on the age of the teachers. Teachers in the age of 30 years or less and 31 to 40 years rated themselves a mean of 3.45 and 3.78, with a standard deviation of 0.56 and 0.47 respectively