Calibration of ultrasonic hardware for enhanced total focusing method imaging

Experimental variation from ultrasonic hardware is one source of uncertainty in measured ultrasonic data. This uncertainty leads to a reduction in the accuracy of images generated from these data. In this paper, a quick, easy-to-use and robust methodology is proposed to reduce this uncertainty in images generated using the total focusing method (TFM). Using a 128-element linear phased array, multiple full matrix capture (FMC) datasets of a planar reflection are used to characterise the experimental variation associated with each element index in the aperture. Following this, a methodology to decouple the time-domain error associated with transmission and reception at each element index is presented. These time-domain errors are then introduced into a simulated array model used to generate the two-way pressure profile from the array. The side-lobe-to-main-lobe energy ratio (SMER) and beam offset are used to quantify the impact of these measured time-domain errors on the pressure profile. This analysis shows that the SMER is raised by more than 6 dB and the beam is offset by more than 1 mm from its programmed focal position. This calibration methodology is then demonstrated using a steel non-destructive testing (NDT) sample with three side-drilled holes (SDHs). The time delay errors from transmission and reception are introduced into the time-of-flight (TOF) calculation for each ray path in the TFM. This results in an enhancement in the accuracy of defect localisation in the TFM image

mTOR Complex 2 Is Required for the Development of Prostate Cancer Induced by Pten Loss in Mice

mTOR complex 2 (mTORC2) contains the mammalian target of rapamycin (mTOR) kinase and the Rictor regulatory protein and phosphorylates Akt. Whether this function of mTORC2 is critical for cancer progression is unknown. Here, we show that transformed human prostate epithelial cells lacking PTEN require mTORC2 to form tumors when injected into nude mice. Furthermore, we find that Rictor is a haploinsufficient gene and that deleting one copy protects Pten heterozygous mice from prostate cancer. Finally, we show that the development of prostate cancer caused by Pten deletion specifically in prostate epithelium requires mTORC2, but that for normal prostate epithelial cells, mTORC2 activity is nonessential. The selective requirement for mTORC2 in tumor development suggests that mTORC2 inhibitors may be of substantial clinical utility.W. M. Keck FoundationDamon Runyon Cancer Research Foundation (Research Fellowship)Leukemia & Lymphoma Society of America (Career Development Award)Howard Hughes Medical Institute (Investigator)National Institutes of Health (U.S.) (K99 CA1296613-01A1)National Institutes of Health (U.S.) (R01 CA107166)National Institutes of Health (U.S.) (R01 AI04389)National Institutes of Health (U.S.) (R01 CA103866

First observation of excited states in 173Hg

The neutron-deficient nucleus 173Hg has been studied following fusion-evaporation reactions. The observation of gamma rays decaying from excited states are reported for the first time and a tentative level scheme is proposed. The proposed level scheme is discussed within the context of the systematics of neighbouring neutron-deficient Hg nuclei. In addition to the gamma-ray spectroscopy, the alpha decay of this nucleus has been measured yielding superior precision to earlier measurements.Comment: 5 pages, 4 figure

The emergence and current performance of a health research system: lessons from Guinea Bissau

<p>Abstract</p> <p>Background</p> <p>Little is known about how health research systems (HRS) in low-income countries emerge and evolve over time, and how this process relates to their performance. Understanding how HRSs emerge is important for the development of well functioning National Health Research Systems (NHRS). The aim of this study was to assess how the HRS in Guinea Bissau has emerged and evolved over time and how the present system functions.</p> <p>Methods</p> <p>We used a qualitative case-study methodology to explore the emergence and current performance of the HRS, using the NHRS framework. We reviewed documents and carried out 39 in-depth interviews, ranging from health research to policy and practice stakeholders. Using an iterative approach, we undertook a thematic analysis of the data.</p> <p>Results</p> <p>The research practices in Guinea Bissau led to the emergence of a HRS with both local and international links and strong dependencies on international partners and donors. The post-colonial, volatile and resource-dependent context, changes in donor policies, training of local researchers and nature of the research findings influenced how the HRS evolved. Research priorities have mostly been set by 'expatriate' researchers and focused on understanding and reducing child mortality. Research funding is almost exclusively provided by foreign donors and international agencies. The training of Guinean researchers started in the mid-nineties and has since reinforced the links with the health system, broadened the research agenda and enhanced local use of research. While some studies have made an important contribution to global health, the use of research within Guinea Bissau has been constrained by the weak and donor dependent health system, volatile government, top-down policies of international agencies, and the controversial nature of some of the research findings.</p> <p>Conclusions</p> <p>In Guinea Bissau a de facto 'system' of research has emerged through research practices and co-evolving national and international research and development dynamics. If the aim of research is to contribute to local decision making, it is essential to modulate the emerged system by setting national research priorities, aligning funding, building national research capacity and linking research to decision making processes. Donors and international agencies can contribute to this process by coordinating their efforts and aligning to national priorities.</p

Controlling for Prior Attainment Reduces the Positive Influence that Single-Gender Classroom Initiatives Exert on High School Students’ Scholastic Achievements.

Research points to the positive impact that gender-segregated schooling and classroom initiatives exert on academic attainment. An evaluation of these studies which reveal positive effects highlights, however, that students are typically selectively assigned to single- or mixed-gender instructional settings, presenting a methodological confound. The current study controls for students’ prior attainment to appraise the efficacy of a single-gender classroom initiative implemented in a co-educational high school in the United Kingdom. Secondary data analysis (using archived data) was performed on 266 middle-ability, 11–12 year-old students’ standardized test scores in Languages (English, foreign language), STEM-related (Mathematics, Science, Information and Communication Technology), and Non-STEM subjects (art, music, drama). Ninety-eight students (54, 55% female) were taught in single-gender and 168 (69, 41% female) in mixed-gender classrooms. Students undertook identical tests irrespective of classroom type, which were graded in accordance with U.K national curriculum guidelines. Controlling for students’ prior attainment, findings indicate that students do not appear to benefit from being taught in single-gender relative to mixed-gender classrooms in Language and STEM-related subjects. Young women benefitted from being taught in mixed-gender relative to single-gender classes for Non-STEM subjects. However, when prior ability is not controlled for, the intervention appears to be effective for all school subjects, highlighting the confounding influence of selective admissions. These findings suggest that gender-segregated classroom initiatives may not bolster students’ grades. It is argued that studies that do not control for selection effects may tell us little about the effectiveness of such interventions on scholastic achievement

Reconstruction of refractive index maps using photogrammetry

Large volume metrology is a key enabler of autonomous precision manufacturing. For component positioning, the optical-based metrology technique of photogrammetry could be used more widely if its accuracy was improved. These positional measurements are subject to uncertainties which can be greater than manufacturing tolerances. One source of uncertainty is due to thermal gradients, which cause the refraction of the light rays in large-scale industrial environments. This paper uses light-based sensor data to reconstruct a heterogeneous spatial map of the refractive index in air. We use this reconstructed refractive index map to discount the refractive effects and thereby reduce the uncertainty of this positioning problem. This new inverse problem employs Voronoi tessellations to spatially parameterize the refractive index map, the Fast Marching Method to solve the forward problem of calculating the light rays through this medium, and a Bayesian approach in the inversion. Using simulated data, this methodology leads to positioning improvements of up to 37 (Formula presented.)