Surface Acoustic Wave induced Transport in a Double Quantum Dot

We report on non-adiabatic transport through a double quantum dot under irradiation of surface acoustic waves generated on-chip. At low excitation powers, absorption and emission of single and multiple phonons is observed. At higher power, sequential phonon assisted tunneling processes excite the double dot in a highly non-equilibrium state. The present system is attractive for studying electron-phonon interaction with piezoelectric coupling.Comment: 4 pages, 3 figure

Explaining a Productive Decade

This paper analyzes the sources of recent U.S. productivity growth using both aggregate and industry-level data. The paper confirms the central role of information technology in the productivity revival during 1995-2000 and shows that it played a significant, although smaller, role after 2000. Productivity growth after 2000 appears to have been boosted by industry restructuring and cost cutting in response to profit pressures, an unlikely source of future strength. In addition, the incorporation of intangible capital into the growth accounting framework somewhat diminishes estimates of labor productivity's performance since 2000 and makes the gain during 1995-2000 look larger than in the official data. Finally, the paper examines the outlook for trend growth in labor productivity; the resulting estimate, which is subject to much uncertainty, is centered at 2 1/4 percent a year, faster than the lackluster pace that prevailed before 1995 but somewhat slower than the 1995-2000 average.macroeconomics, productivity growth, labor productivity

Reassessing the Social Returns to Equipment Investment

The recent literature on the sources of economic growth has challenged the traditional growth accounting of the Solow model, which assigned a relatively limited role to capital deepening. As part of this literature, De Long and Summers have argued in two papers that the link between equipment investment and economic growth across countries is stronger than can be generated by the Solow model. Accordingly, they conclude that such investment yields important external benefits. However, their analysis suffers from two shortcomings. First, De Long and Summers have not conducted any formal statistical tests of the Solow model. Second, even their informal rejection of the model fails to survive reasonable tests of robustness. We formally test the predictions of the Solow model using De Long and Summers' data. Our results cast doubt on the existence of externalities to equipment investment. In particular, we find that the empirical link between investment and growth in the OECD countries is fully consistent with the Solow model. Moreover, for De Long and Summers' full sample, the evidence of excess returns to equipment investment is tenuous.

Traditional and Health-Related Philanthropy: The Role of Resources and Personality

I study the relationships of resources and personality characteristics to charitable giving, postmortem organ donation, and blood donation in a nationwide sample of persons in households in the Netherlands. I find that specific personality characteristics are related to specific types of giving: agreeableness to blood donation, empathic concern to charitable giving, and prosocial value orientation to postmortem organ donation. I find that giving has a consistently stronger relation to human and social capital than to personality. Human capital increases giving; social capital increases giving only when it is approved by others. Effects of prosocial personality characteristics decline at higher levels of these characteristics. Effects of empathic concern, helpfulness, and social value orientations on generosity are mediated by verbal proficiency and church attendance.

A comparability study of 5 commercial KRAS tests

<p>Abstract</p> <p>Background</p> <p>Activating mutations in the <it>KRAS </it>gene occur frequently in human tumors, including colorectal carcinomas; most mutations occur in codons 12 and 13. Mutations in <it>KRAS </it>have been associated with poor response to anti-epidermal growth factor receptor antibodies. Therefore, an accurate and readily available analysis of <it>KRAS </it>mutational status is needed. The aim of this study was to evaluate concordance between <it>KRAS </it>assays performed by 6 different laboratories.</p> <p>Methods</p> <p>Forty formalin-fixed paraffin-embedded colorectal cancer tumor samples were obtained. Sample sections were submitted for <it>KRAS </it>mutation analysis to 5 independent commercial laboratories (Agencourt, Gentris, Genzyme, HistoGeneX, and Invitek) and to the Amgen DNA Sequencing Laboratory for direct polymerase chain reaction sequencing. The assay used by Invitek is no longer commercially available and has been replaced by an alternative technique. Results from the commercial services were compared with those from Amgen direct sequencing by κ statistics.</p> <p>Results</p> <p><it>KRAS </it>mutations were observed in codon 12 and/or 13 in 20 of 40 (50%) samples in Amgen direct sequencing assays. Results from HistoGeneX (κ = 0.95), Genzyme (κ = 0.94), and Agencourt (κ = 0.94) were in almost perfect agreement with these results, and the results from Gentris were in substantial agreement with the results from Amgen (κ = 0.75). The Invitek allele-specific assay demonstrated slight agreement (κ = 0.13).</p> <p>Conclusions</p> <p>This study provides data on the comparability of <it>KRAS </it>mutational analyses. The results suggest that most (but not all) commercial services provide analysis that is accurate and comparable with direct sequencing.</p

'Education, education, education' : legal, moral and clinical

This article brings together Professor Donald Nicolson's intellectual interest in professional legal ethics and his long-standing involvement with law clinics both as an advisor at the University of Cape Town and Director of the University of Bristol Law Clinic and the University of Strathclyde Law Clinic. In this article he looks at how legal education may help start this process of character development, arguing that the best means is through student involvement in voluntary law clinics. And here he builds upon his recent article which argues for voluntary, community service oriented law clinics over those which emphasise the education of students

The Company You Keep : Mobile Malware Infection Rates and Inexpensive Risk Indicators

There is little information from independent sources in the public domain about mobile malware infection rates. The only previous independent estimate (0.0009%) [12], was based on indirect measurements obtained from domain name resolution traces. In this paper, we present the first independent study of malware infection rates and associated risk factors using data collected directly from over 55,000 Android devices. We find that the malware infection rates in Android devices estimated using two malware datasets (0.28% and 0.26%), though small, are significantly higher than the previous independent estimate. Using our datasets, we investigate how indicators extracted inexpensively from the devices correlate with malware infection. Based on the hypothesis that some application stores have a greater density of malicious applications and that advertising within applications and cross-promotional deals may act as infection vectors, we investigate whether the set of applications used on a device can serve as an indicator for infection of that device. Our analysis indicates that this alone is not an accurate indicator for pinpointing infection. However, it is a very inexpensive but surprisingly useful way for significantly narrowing down the pool of devices on which expensive monitoring and analysis mechanisms must be deployed. Using our two malware datasets we show that this indicator performs 4.8 and 4.6 times (respectively) better at identifying infected devices than the baseline of random checks. Such indicators can be used, for example, in the search for new or previously undetected malware. It is therefore a technique that can complement standard malware scanning by anti-malware tools. Our analysis also demonstrates a marginally significant difference in battery use between infected and clean devices

Structural analysis of MDM2 RING separates degradation from regulation of p53 transcription activity

MDM2–MDMX complexes bind the p53 tumor-suppressor protein, inhibiting p53's transcriptional activity and targeting p53 for proteasomal degradation. Inhibitors that disrupt binding between p53 and MDM2 efficiently activate a p53 response, but their use in the treatment of cancers that retain wild-type p53 may be limited by on-target toxicities due to p53 activation in normal tissue. Guided by a novel crystal structure of the MDM2–MDMX–E2(UbcH5B)–ubiquitin complex, we designed MDM2 mutants that prevent E2–ubiquitin binding without altering the RING-domain structure. These mutants lack MDM2's E3 activity but retain the ability to limit p53′s transcriptional activity and allow cell proliferation. Cells expressing these mutants respond more quickly to cellular stress than cells expressing wild-type MDM2, but basal p53 control is maintained. Targeting the MDM2 E3-ligase activity could therefore widen the therapeutic window of p53 activation in tumors

Scrub: Online TroubleShooting for Large Mission-Critical Applications

Scrub is a troubleshooting tool for distributed applications that operate under strict SLOs common in production environments. It allows users to formulate queries on events occurring during execution in order to assess the correctness of the application’s operation. Scrub has been in use for two years at Turn, where developers and users have relied on it to resolve numerous issues in its online advertisement bidding platform. This platform spans thousands of machines across the globe, serving several million bid requests per second, and dispensing many millions of dollars in advertising budgets. Troubleshooting distributed applications is notoriously hard, and its difficulty is exacerbated by the presence of strict SLOs, which requires the troubleshooting tool to have only minimal impact on the hosts running the application. Furthermore, with large amounts of money at stake, users expect to be able to run frequent diagnostics and demand quick evaluation and remediation of any problems. These constraints have led to a number of design and implementation decisions, that go counter to conventional wisdom. In particular, Scrub supports only a restricted form of joins. Its query execution strategy eschews imposing any overhead on the application hosts. In particular, joins, group-by operations and aggregations are sent to a dedicated centralized facility. In terms of implementation, Scrub avoids the overhead and security concerns of dynamic instrumentation. Finally, at all levels of the system, accuracy is traded for minimal impact on the hosts. We present the design and implementation of Scrub and contrast its choices to those made in earlier systems. We illustrate its power by describing a number of use cases, and we demonstrate its negligible overhead on the underlying application. On average, we observe a maximum CPU overhead of up to 2.5% on application hosts and a 1% increase in request latency. These overheads allow the advertisement bidding platform to operate well within its SLOs