Exploiting dynamic timing margins in microprocessors for frequency-over-scaling with instruction-based clock adjustment

Static timing analysis provides the basis for setting the clock period of a microprocessor core, based on its worst-case critical path. However, depending on the design, this critical path is not always excited and therefore dynamic timing margins exist that can theoretically be exploited for the benefit of better speed or lower power consumption (through voltage scaling). This paper introduces predictive instruction-based dynamic clock adjustment as a technique to trim dynamic timing margins in pipelined microprocessors. To this end, we exploit the different timing requirements for individual instructions during the dynamically varying program execution flow without the need for complex circuit-level measures to detect and correct timing violations. We provide a design flow to extract the dynamic timing information for the design using post-layout dynamic timing analysis and we integrate the results into a custom cycle-accurate simulator. This simulator allows annotation of individual instructions with their impact on timing (in each pipeline stage) and rapidly derives the overall code execution time for complex benchmarks. The design methodology is illustrated at the microarchitecture level, demonstrating the performance and power gains possible on a 6-stage OpenRISC in-order general purpose processor core in a 28nm CMOS technology. We show that employing instruction-dependent dynamic clock adjustment leads on average to an increase in operating speed by 38% or to a reduction in power consumption by 24%, compared to traditional synchronous clocking, which at all times has to respect the worst-case timing identified through static timing analysis.

Mode of prostate cancer detection is associated with the psychological wellbeing of survivors: results from the PiCTure study

Purpose: Many men with prostate cancer are asymptomatic, diagnosed following prostate specific antigen (PSA) testing. We investigate whether mode of detection, i.e. ‘PSA detected’ or ‘clinically detected’, was associated with psychological wellbeing among prostate cancer survivors. Methods: A cross-sectional postal questionnaire was administered in 2012 to 6559 prostate cancer (ICD10 C61) survivors up to 18 years post-diagnosis, identified through population-based cancer registries in Ireland. Psychological wellbeing was assessed using the Depression Anxiety Stress Scale-21. Logistic regression was used to investigate associations between mode of detection and depression, anxiety and stress, adjusting for socio-demographic and clinical confounders. Results: The response rate was 54 % (3348/6262). Fifty-nine percent of survivors were diagnosed with asymptomatic PSA-tested disease. Prevalence of depression (13.8 vs 20.7 %; p < 0.001), anxiety (13.6 vs 20.9 %; p < 0.001) and stress (8.7 vs 13.8 %; p < 0.001) were significantly lower among survivors diagnosed with PSA-detected, than clinically detected disease. After adjusting for clinical and socio-demographic factors, survivors with clinically detected disease had significantly higher risk of depression (odds ratio (OR) = 1.46 95 % CI 1.18, 1.80; p = 0.001), anxiety (OR = 1.36 95 % CI 1.09, 1.68; p = 0.006) and stress (OR = 1.43 95 % CI 1.11, 1.85; p = 0.006) than survivors with PSA-detected disease. Conclusions: These findings contribute to the ongoing debate on benefits and risks of PSA testing and may be considered by policy makers formulating population-based prostate cancer screening policies. The relatively high prevalence of negative psychological states among survivors means that a ‘risk-adapted approach’ should be implemented to screen survivors most at risk of psychological morbidity for psychological health, and mode of detection could be considered as a risk stratum.

Protocol-driven adjustment of ocular hypotensive medication in patients at low risk of conversion to glaucoma

AIM: To investigate the safety and potential savings of decreasing medication use in low-risk patients with ocular hypertension (OH).
METHODS: Patients with OH receiving pressure-lowering medication identified by medical record review at a university hospital underwent examination by a glaucoma specialist with assessment of visual field (VF), vertical cup-to-disc ratio (vCDR), central corneal thickness and intraocular pressure (IOP). Subjects with estimated 5-year risk of glaucoma conversion <15% were asked to discontinue ≥1 medication, IOP was remeasured 1 month later and risk was re-evaluated at 1 year.
RESULTS: Among 212 eyes of 126 patients, 44 (20.8%) had 5-year risk >15% and 14 (6.6%) had unreliable baseline VF. At 1 month, 15 patients (29 eyes, 13.7%) defaulted follow-up or refused to discontinue medication and 11 eyes (5.2%) had risk >15%. The remaining 69 patients (107 eyes, 50.7%) successfully discontinued 141 medications and completed 1-year follow-up. Mean IOP (20.5±2.65 mm Hg vs 20.3±3.40, p=0.397) did not change, though mean VF pattern SD (1.58±0.41 dB vs 1.75±0.56 dB, p=0.001) and glaucoma conversion risk (7.31±3.74% vs 8.76±6.28%, p=0.001) increased at 1 year. Mean defect decreased (-1.42±1.60 vs -1.07±1.52, p=0.022). One eye (0.47%) developed a repeatable VF defect and 13 eyes (6.1%) had 5-year risk >15% at 1 year. The total 1-year cost of medications saved was US$4596.
CONCLUSIONS: Nearly half (43.9%) of low-risk OH eyes in this setting could safely reduce medications over 1 year, realising substantial savings.Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Nuclear cataract shows significant familial aggregation in an older population after adjustment for possible shared environmental factors.

PURPOSE: To quantify the association between siblings in age-related nuclear cataract, after adjusting for known environmental and personal risk factors. METHODS: All participants (probands) in the Salisbury Eye Evaluation (SEE) project and their locally resident siblings underwent digital slit lamp photography and were administered a questionnaire to assess risk factors for cataract including: age, gender, lifetime sun exposure, smoking and diabetes history, and use of alcohol and medications such as estrogens and steroids. In addition, blood pressure, body mass index, and serum antioxidants were measured in all participants. Lens photographs were graded by trained observers masked to the subjects' identity, using the Wilmer Cataract Grading System. The odds ratio for siblings for affectedness with nuclear cataract and the sibling correlation of nuclear cataract grade, after adjusting for covariates, were estimated with generalized estimating equations. RESULTS: Among 307 probands (mean age, 77.6 +/- 4.5 years) and 434 full siblings (mean age, 72.4 +/- 7.4 years), the average sibship size was 2.7 per family. After adjustment for covariates, the probability of development of nuclear cataract was significantly increased (odds ratio [OR] = 2.07, 95% confidence interval [CI], 1.30-3.30) among individuals with a sibling with nuclear cataract (nuclear grade > or = 3.0). The final fitted model indicated a magnitude of heritability for nuclear cataract of 35.6% (95% CI: 21.0%-50.3%) after adjustment for the covariates. CONCLUSIONS: Findings in this study are consistent with a genetic effect for age-related nuclear cataract, a common and clinically significant form of lens opacity.

Cortical, but not posterior subcapsular, cataract shows significant familial aggregation in an older population after adjustment for possible shared environmental factors.

PURPOSE:

To quantify the risk for age-related cortical cataract and posterior subcapsular cataract (PSC) associated with having an affected sibling after adjusting for known environmental and personal risk factors.

DESIGN:

Sibling cohort study.

PARTICIPANTS:

Participants in the ongoing Salisbury Eye Evaluation (SEE) study (n = 321; mean age, 78.1+/-4.2 years) and their locally resident siblings (n = 453; mean age, 72.6+/-7.4 years) were recruited at the time of Rounds 3 and 4 of the SEE study. INTERVENTION/TESTING METHODS: Retroillumination photographs of the lens were graded for the presence of cortical cataract and PSC with the Wilmer grading system. The residual correlation between siblings' cataract grades was estimated after adjustment for a number of factors (age; gender; race; lifetime exposure to ultraviolet-B light; cigarette, alcohol, estrogen, and steroid use; serum antioxidants; history of diabetes; blood pressure; and body mass index) suspected to be associated with the presence of cataract.

RESULTS:

The average sibship size was 2.7 per family. Multivariate analysis revealed the magnitude of heritability (h(2)) for cortical cataract to be 24% (95% CI, 6%-42%), whereas that for PSC was not statistically significant (h(2) 4%; 95% CI, 0%-11%) after adjustment for the covariates. The model revealed that increasing age, female gender, a history of diabetes, and black race increased the odds of cortical cataract, whereas higher levels of provitamin A were protective. A history of diabetes and steroid use increased the odds for PSC.

CONCLUSIONS:

This study is consistent with a significant genetic effect for age-related cortical cataract but not PSC.

Change in psychological distress in longer-term oesophageal cancer carers: are clusters of illness perception change a useful determinant?

Objective: This study provides a longitudinal assessment of distress in longer-term oesophageal cancer carers, while examining illness perception schema as a possible determinant of change in distress over time.
Methods: Oesophageal cancer carers (n=171), 48-months post-diagnosis, were assessed at baseline and 12-months later with the Illness Perception Questionnaire-Revised, Cancer Coping Questionnaire, Hospital Anxiety and Depression Scale and Concerns About Recurrence Scale.
Results: Findings report deterioration from normal to probable anxiety in 35.7% of carers and probable depression in 28.7% carers over time. Fear of recurrence remained stable. Changes in control, consequence and cause beliefs were identified as key determinants of a change in psychological morbidity.
Conclusions: Illness beliefs appear to be valuable targets for psychological intervention to improve wellbeing among carers of people with oesophageal cancer.

Psychological interventions for children and young people affected by armed conflict or political violence: a systematic literature review.

Youths exposed to armed conflict have a higher prevalence of mental health and psychosocial difficulties. Diverse interventions exist that aim to ameliorate the effect of armed conflict on the psychological and psychosocial wellbeing of conflict affected youths. However, the evidence base for the effectiveness of these interventions is limited. Using standard review methodology, this review aims to address the effectiveness of psychological interventions employed among this population. The search was performed across four databases and grey literature. Article quality was assessed using the Downs and Black Quality Checklist (1998). Where possible, studies were subjected to meta-analyses. The remaining studies were included in a narrative synthesis. Eight studies concerned non clinical populations, while nine concerned clinical populations. Review findings conclude that Group Trauma Focused-Cognitive Behavioural Therapy is effective for reducing symptoms of posttraumatic stress disorder, anxiety, depression and improving prosocial behaviour among clinical cohorts. The evidence does not suggest that interventions aimed at non clinical groups within this population are effective. Despite high quality studies, further robust trials are required to strengthen the evidence base, as a lack of replication has resulted in a limited evidence base to inform practice.

Systematic review of interventions to improve the psychological well-being of general practitioners

BACKGROUND: The health of doctors who work in primary care is threatened by workforce and workload issues. There is a need to find and appraise ways in which to protect their mental health, including how to achieve the broader, positive outcome of well-being. Our primary outcome was to evaluate systematically the research evidence regarding the effectiveness of interventions designed to improve General Practitioner (GP) well-being across two continua; psychopathology (mental ill-health focus) and 'languishing to flourishing' (positive mental health focus). In addition we explored the extent to which developments in well-being research may be integrated within existing approaches to design an intervention that will promote mental health and prevent mental illness among these doctors.

METHODS: Medline, Embase, Cinahl, PsychINFO, Cochrane Register of Trials and Web of Science were searched from inception to January 2015 for studies where General Practitioners and synonyms were the primary participants. Eligible interventions included mental ill-health prevention strategies (e.g. promotion of early help-seeking) and mental health promotion programmes (e.g. targeting the development of protective factors at individual and organizational levels). A control group was the minimum design requirement for study inclusion and primary outcomes had to be assessed by validated measures of well-being or mental ill-health. Titles and abstracts were assessed independently by two reviewers with 99 % agreement and full papers were appraised critically using validated tools.

RESULTS: Only four studies (with a total of 997 GPs) from 5392 titles met inclusion criteria. The studies reported statistically significant improvement in self-reported mental ill-health. Two interventions used cognitive-behavioural techniques, one was mindfulness-based and one fed-back GHQ scores and self-help information.

CONCLUSION: There is an urgent need for high quality, controlled studies in GP well-being. Research on improving GP well-being is limited by focusing mainly on stressors and not giving systematic attention to the development of positive mental health.

Psychological distress in mothers of children admitted to a nutritional rehabilitation unit in Malawi - a comparison with other paediatric wards

In a previous study we found a very high prevalence of psychological distress in mothers of children admitted to a nutritional rehabilitation unit (NRU) in Malawi, Africa. The objective of this study was to compare the prevalence and severity of maternal distress within the NRU with that in other paediatric wards. Given the known association between poor maternal psychological well-being and child undernutrition in low- and middle-income countries, we hypothesised that distress would be higher among NRU mothers. Mothers of consecutive paediatric inpatients in a NRU, a high-dependency (and research) unit and an oncology ward were assessed for psychological distress using the Self-Reporting Questionnaire (SRQ). Two hundred sixty-eight mothers were interviewed (90.3% of eligible). The prevalence of SRQ score ≥8 was 35/150 {23.3% [95% confidence interval (CI) 16.8- 30.9%]} on the NRU, 13/84 [15.5% (95% CI 8.5-25.0%)] on the high-dependency unit and 7/34 [20.6% (95% CI 8.7-37.9%)] on the oncology ward (χ(2)  = 2.04, P = 0.36). In linear regression analysis, the correlates of higher SRQ score were child diarrhoea on admission, child diagnosed with tuberculosis, and maternal experience of abuse by partner; child height-for-age z-score fell only just outside significance (P = 0.05). In summary, we found no evidence of greater maternal distress among the mothers of severely malnourished children within the NRU compared with mothers of paediatric inpatients with other severe illnesses. However, in support of previous research findings, we found some evidence that poor maternal psychological well-being is associated with child stunting and diarrhoea.