Optimal dynamic remapping of parallel computations

A large class of computations are characterized by a sequence of phases, with phase changes occurring unpredictably. The decision problem was considered regarding the remapping of workload to processors in a parallel computation when the utility of remapping and the future behavior of the workload is uncertain, and phases exhibit stable execution requirements during a given phase, but requirements may change radically between phases. For these problems a workload assignment generated for one phase may hinder performance during the next phase. This problem is treated formally for a probabilistic model of computation with at most two phases. The fundamental problem of balancing the expected remapping performance gain against the delay cost was addressed. Stochastic dynamic programming is used to show that the remapping decision policy minimizing the expected running time of the computation has an extremely simple structure. Because the gain may not be predictable, the performance of a heuristic policy that does not require estimnation of the gain is examined. The heuristic method's feasibility is demonstrated by its use on an adaptive fluid dynamics code on a multiprocessor. The results suggest that except in extreme cases, the remapping decision problem is essentially that of dynamically determining whether gain can be achieved by remapping after a phase change. The results also suggest that this heuristic is applicable to computations with more than two phases

Fabrication of mesoscale topographical gradients in bulk titanium and their use in injection moulding

Fabrication methods for titanium substrates exhibiting continuous micro and nano scale arrays, with increasing feature heights over the length of the array are reported. The resultant feature heights spanned 0–2 μm. Patterned gradient arrays of circular features with diameters of: 500 nm, 1 μm and 2 μm, spaced by twice the diameter were manufactured by the process using specially prepared titanium substrates. Patterns were exposed by electron beam lithography and the length of the patterned arrays was 15 mm or 20 mm. This work presents two selectivity amplification processes to achieve a gradient of feature heights ranging over the titanium array after consecutive reactive ion etching processes. The first, route A: a HSQ on Ti, gradient amplification process. The second, route B, a SiO2 layer amplification transfer into Ti. The crucial initial gradient component deposited for the amplification process for both routes was a diffusion limited plasma polymerised hexane gradient. Etching using respective reactive ion etch chemistries for each gradient transfer through the various selectivity amplification layers (employing consecutive etch steps, in this way) enables a dual amplification for each route to manufacture. The original gradient is transferred into titanium as a function of the sum of the respective selectivities between the materials, using the appropriate dry etch plasma conditions. The substrates henceforth are referred to as inlays, and were tested for use as a high throughput platform for polymer replication by injection moulding. It is envisaged that the fabrication methodology and resultant topographies have use in a range of engineering applications. The overall selectivity to Ti for polymerised hexane is increased by more than 20 times using each dual amplification process

The problems of offenders with mental disorders: A plurality of perspectives within a single mental health care organisation

Managers, doctors, nurses, occupational therapists, social workers, psychologists, unqualified staff and service users were interviewed for a qualitative study of risk management and rehabilitation in an inner city medium secure forensic mental health care unit. Different professional orientations to service user problems were identified. Doctors focused primarily on the diagnosis of mental disorder, which they managed mainly through pharmaceutical interventions. Psychologists were principally concerned with personal factors, for example service user insight into their biographical history. Occupational therapists concentrated mainly on daily living skills, and social workers on post-discharge living arrangements. Some front line nurses, held accountable for security lapses, adopted a criminogenic approach. Service users were more likely than professionals to understand their needs in terms of their wider life circumstances. These differences are explored qualitatively in relation to four models of crossdisciplinary relationships: monoprofessional self-organisation combined with restricted communication; hermeneutic reaching out to other perspectives; the establishment of interdisciplinary sub-systems; and transdisciplinary merger. Relationships between professions working in this unit, as portrayed in qualitative interviews, corresponded mainly to the first model of monoprofessional self-organisation. Reasons for restricted crossdisciplinary understanding, particularly the wide power/status differences between the medical and other professions, and between staff and patients, are discussed

Assessing the probability of patients reoffending after discharge from low to medium secure forensic mental health services: An inductive prevention paradox

Citizens of developed societies are troubled by those who commit ‘irrational' crimes against the person. Reoffending by ex-patients following their release from secure mental health services triggers particularly intense angst when amplified by media and political scrutiny. Forensic mental health service providers are expected to minimise the occurrence of such transgressions by releasing only those patients who are judged acceptably unlikely to reoffend. However, reoffending probabilities can only be estimated by observing behaviour in secure institutional settings designed specifically to prevent patients from transgressing. The article explores this ‘inductive prevention paradox' which arises when the implementation of measures designed to avoid an adverse event obscures direct observation of what might have happened if prophylaxis had not been attempted. The analysis presented draws on data obtained in 1999–2003 from two qualitative studies in medium to low secure UK institutions, one providing forensic mental health services and the other forensic learning disability services. We explored the views of 56 staff members and 21 patients about risk management in forensic services and undertook additional 25 staff interviews for case studies of the 21 patients. The wider applicability of the inductive prevention paradox will be considered in the Discussion. We argue that the prognostic limitations arising from prevention have been underestimated by policy makers and in official inquiries; and that the prevailing personal risk assessment framework needs to be complemented by greater attention to the environments which patients will be discharged into

Combining yield potential and drought resilience in a spring wheat diversity panel

Pressures of population growth and climate change require the development of resilient higher yielding crops, particularly to drought. A spring wheat diversity panel was developed to combine high‐yield potential with resilience. To assess performance under drought, which in many environments is intermittent and dependent on plant development, 150 lines were grown with drought imposed for 10 days either at jointing or at anthesis stages in Obregon, Mexico. Both drought treatments strongly reduced grain numbers compared with the fully irrigated check. Best performers under drought at jointing had more grain than poor performers, while best performers under drought at anthesis had larger grain than poor performers. Most high‐yielding lines were high yielding in one drought environment only. However, some of the best‐performing lines displayed yield potential and resilience across two environments (28 lines), particularly for yield under well‐watered and drought at jointing, where yield was most related to grain numbers. Strikingly, only three lines were high yielding across all three environments, and interestingly, these lines had high grain numbers. Among parameters measured in leaves and grain, leaf relative water content did not correlate with yield, and proline was negatively correlated with yield; there were small but significant relationships between leaf sugars and yield. This study provides a valuable resource for further crosses and for elucidating genes and mechanisms that may contribute to grain number and grain filling conservation to combine yield potential and drought resilience

Enhanced differentiation of human embryonic stem cells towards definitive endoderm on ultrahigh aspect ratio nanopillars

Differentiation of human embryonic stem cells is widely studied as a potential unlimited source for cell replacement therapy to treat degenerative diseases such as diabetes. The directed differentiation of human embryonic stem cells relies mainly on soluble factors. Although, some studies have highlighted that the properties of the physical environment, such as substrate stiffness, affect cellular behavior. Here, mass-produced, injection molded polycarbonate nanopillars are presented, where the surface mechanical properties, i.e., stiffness, can be controlled by the geometric design of the ultrahigh aspect ratio nanopillars (stiffness can be reduced by 25.0003). It is found that tall nanopillars, yielding softer surfaces, significantly enhance the induction of definitive endoderm cells from pluripotent human embryonic stem cells, resulting in more consistent differentiation of a pure population compared to planar control. By contrast, further differentiation toward the pancreatic ­endoderm is less successful on “soft” pillars when compared to “stiff” pillars or control, indicating differential cues during the different stages of differentiation. To accompany the mechanical properties of the nanopillars, the concept of surface shear modulus is introduced to describe the characteristics of engineered elastic surfaces through micro or nanopatterning. This provides a framework whereby comparisons can be drawn between such materials and bulk elastomeric materials

Intrinsic religiosity attenuates the negative relationship between social disconnectedness and meaning in life

Positive social connections are integral to people’s experience of meaning in their lives. As such, social isolation can make life seem meaningless. Chan, Michalak, and Ybarra (2019, Journal of Personality) provided evidence that religious beliefs (not just participation in corporate religious life) can provide an alternative source of meaning for people who feel socially isolated. We tested whether this phenomenon was specific to (a) intrinsic versus extrinsic orientations toward religion and (b) experiencing meaning in one’s life at present versus actively searching for meaning. In a sample of undergraduates, high levels of intrinsic—but not extrinsic—religiosity attenuated the relationship between social disconnection and decreased meaning in life. Moreover, this attenuation was specific to felt presence of meaning in life, rather than active search for meaning. These results corroborate and expand Chan et al.’s findings and suggest that future research should explore mechanisms by which religious beliefs themselves serve meaning-making functions

Association of N-terminal pro-brain natriuretic peptide with cognitive function and depression in elderly people with type 2 diabetes

<p>Background: Type 2 diabetes mellitus is associated with risk of congestive heart failure (CHF), cognitive dysfunction and depression. CHF itself is linked both to poor cognition and depression. The ventricular N-terminal pro-brain natriuretic peptide (NT-proBNP) is a marker of CHF, suggesting potential as a marker for cognitive impairment and/or depression. This was tested in the Edinburgh Type 2 Diabetes Study (ET2DS).</p> <p>Methodology and Principal Findings: Cross-sectional analysis of 1066 men and women aged 60–75 with type 2 diabetes. Results from seven neuropsychological tests were combined in a standardised general cognitive ability factor, ‘g’. A vocabulary-based test estimated pre-morbid cognitive ability. The Hospital Anxiety and Depression Scale (HADS) assessed possible depression. After adjustment for age and sex, raised plasma NT-proBNP was weakly associated with lower ‘g’ and higher depression scores (ß −0.09, 95% CI −0.13 to −0.03, p = 0.004 and ß 0.08, 95% CI 0.04 to 0.12, p<0.001, respectively). Comparing extreme quintiles of NT-proBNP, subjects in the highest quintile were more likely to have reduced cognitive ability (within the lowest tertile of ‘g’) and ‘possible’ depression (HADS depression ≥8) (OR 1.80; 95% CI: 1.20, 2.70; p = 0.005 and OR 2.18; 95% CI: 1.28, 3.71; p = 0.004, respectively). Associations persisted when pre-morbid ability was adjusted for, but as expected were no longer statistically significant following the adjustment for diabetes-related and vascular co-variates (β −0.02, 95% CI −0.07 to 0.03, p>0.05 for ‘g’; β 0.03, 95% CI −0.02 to 0.07, p>0.05 for depression scores).</p> <p>Conclusion: Raised plasma NT-proBNP was weakly but statistically significantly associated with poorer cognitive function and depression. The prospective phases of the ET2DS will help determine whether or not NT-proBNP can be considered a risk marker for subsequent cognitive impairment and incident depression and whether it provides additional information over and above traditional risk factors for these conditions.</p&gt

What is on Tap? The Role of Spin in Compact Objects and Relativistic Jets

We examine the role of spin in launching jets from compact objects across the mass scale. Our work includes a total of 37 Seyferts, 11 stellar-mass black holes, and 13 neutron stars. We find that when the Seyfert reflection lines are modeled with Gaussian line features (a crude proxy for inner disk radius and therefore spin), only a slight inverse correlation is found between the Doppler-corrected radio luminosity at 5 GHz (a proxy for jet power) and line width. When the Seyfert reflection features are fit with relativistically-blurred disk reflection models that measure spin, there is a tentative positive correlation between the Doppler-corrected radio luminosity and the spin measurement. Further, when we include stellar-mass black holes in the sample, to examine the effects across the mass scale, we find a slightly stronger correlation with radio luminosity per unit mass and spin, at a marginal significance (2.3 sigma confidence level). Finally, when we include neutron stars, in order to probe lower spin values, we find a positive correlation (3.3 sigma confidence level) between radio luminosity per unit mass and spin. Although tentative, these results suggest that spin may have a role in determining the jet luminosity. In addition, we find a slightly more significant correlation (4.4 sigma confidence level) between radio luminosity per Bolometric luminosity and spin, using our entire sample of black holes and neutrons stars. Again, although tentative, these relations point to the possibility that the mass accretion rate, i.e. Bolometric luminosity, is also important in determining the jet luminosity, in addition to spin. Our analysis suggests that mass accretion rate and disk or coronal magnetic field strength may be the "throttle" in these compact systems, to which the Eddington limit and spin may set the maximum jet luminosity that can be achieved.Comment: 14 pages, 13 Figures, ApJ Accepte