The role of large-scale energy storage design and dispatch in the power grid: A study of very high grid penetration of variable renewable resources

We present a result of hourly simulation performed using hourly load data and the corresponding simulated output of wind and solar technologies distributed throughout the state of California. We examined how we could achieve very high-energy penetration from intermittent renewable system into the electricity grid. This study shows that the maximum threshold for the storage need is significantly less than the daily average demand. In the present study, we found that the approximate network energy storage is of the order of 186. GW. h/22. GW (approximately 22% of the average daily demands of California). Allowing energy dumping was shown to increase storage use, and by that way, increases grid penetration and reduces the required backup conventional capacity requirements. Using the 186. GW. h/22. GW storage and at 20% total energy loss, grid penetration was increased to approximately 85% of the annual demand of the year while also reducing the conventional backup capacity requirement to 35. GW. This capacity was sufficient to supply the year round hourly demand, including 59 GW peak demand, plus a distribution loss of about 5.3%. We conclude that designing an efficient and least cost grid may require the capability to capture diverse physical and operational policy scenarios of the future grid. © 2014 Elsevier Ltd

The essential signature of a massive starburst in a distant galaxy

Observations of carbon monoxide (CO) emission in high redshift (z>2) galaxies indicate the presence of large amounts of molecular gas. Many of these galaxies contain an active galactic nucleus (AGN) powered by accretion of gas onto a supermassive black hole, and a key question is whether their extremely high infrared luminosities result from the AGN, or from bursts of massive star formation (associated with the molecular gas), or both. In the Milky Way, high-mass stars form in the dense cores of interstellar molecular clouds; gas densities are n(H2)>105 cm-3 in the cores. Recent surveys show that virtually all galactic sites of high-mass star formation have similarly high densities. The bulk of the cloud material traced by CO observations is at a much lower density. In galaxies in the local Universe, the HCN(J=1-0) line is an effective tracer of the high-density molecular gas. Here we report observations of HCN emission in the early Universe from the infrared luminous 'Cloverleaf' quasar (at a redshift z=2.5579). The HCN line luminosity indicates the presence of 10 billion solar masses of very dense gas, an essential feature of an immense starburst that contributes, together with the AGN it harbors, to its high infrared luminosity.Comment: PDF pape

How did a lower drink‐drive limit affect bar trade and drinking practices?:A qualitative study of how alcohol retailers experienced a change in policy

Introduction and Aims Reducing the legal drink-drive limit from 0.08% to 0.05% blood alcohol concentration (BAC) can reduce road traffic accidents and deaths if properly enforced. Reduced limits may be opposed by alcohol retail and manufacturing industries on the basis of commercial impact. Our aim was to qualitatively explore how a reduction in the drink-drive limit from 0.08% to 0.05% BAC in Scotland, was experienced by bar owners or managers, including any resultant changes in customer drinking or business practice. This is the first study of this type. Design and Methods Semi-structured interviews were conducted with 16 owners and managers of on-trade premises in Scotland in 2018, approximately 3 years after the drink-drive limit was reduced. Data were analysed using thematic analysis. Results Most participants reported no long-term financial impact on their business, but a few, mainly from rural areas, reported some reduction in alcohol sales. Observed drinking changes included fewer people drinking after work or leaving premises earlier on weekdays. Adaptations to businesses included improving the range of no/low-alcohol drinks and food offered. Changes such as these were seen as key to minimising economic impact. Discussion and Conclusions Opposition to legislative measures that impact on commercial interests is often strong and receives significant public attention. This study found that Scottish businesses that adapted to the drink-drive limit change reported little long-term economic impact. These findings are of international relevance as potential BAC limit reductions in several other jurisdictions remain the subject of debate, including regarding the impact on business

Uterine rupture among mothers admitted for obstetrics care and associated factors in referral hospitals of Amhara regional state, institution-based cross-sectional study, Northern Ethiopia, 2013-2017.

BACKGROUND: Maternal morbidity and mortality have been one of the most challenging health problems that concern the globe over the years. Uterine rupture is one of the peripartum complications, which cause nearly about one out of thirteen maternal deaths. This study aimed to assess the prevalence and associated factors of uterine rupture among obstetric case in referral hospitals of Amhara Regional State, Northern Ethiopia. METHODS: Institution based cross sectional study was conducted from Dec 5-2017-Jan 5-2018 on uterine rupture. During the study randomly selected 750 charts were included by using simple random sampling method. Data were checked, coded and entered into Epi info version 7.2 and then exported to SPSS Version 20 for Analysis. Binary Logistic regression was used to identify the predictors of uterine rupture and 95% Confidence Interval of odds ratio at p-value less than 0.05 was taken as a significance level. RESULT: The overall prevalence of uterine rupture was 16.68% (95% CI: 14%, 19.2%). Distance from health facility >10km (Adjusted Odds Ratio (AOR) = 2.44; 95%CI:1.13,5.28), parity between II and IV (AOR = 7.26;95% (3.06,17.22)) and ≥V (AOR = 12.55;95% CI 3.64,43.20), laboring for >24hours(AO = 3.44; 95% CI:1.49,7.92), with referral paper(AOR = 2.94;95%CI:1.28,6.55) diagnosed with obstructed labor (AOR = 4.88;95%CI: 2.22,10.70), precipitated labor (AOR = 3.59;95%CI:1.10,11.77), destructive delivery (AOR = 5.18;95%: 1.22,20.08), No partograph (AOR = 5.21; 95% CI: 2.72,9.97), CPD(AOR = 4.08;95%CI:1.99,8.33), morbidly adherent placenta (AOR = 9.00;95%:2.46,27.11), gestational diabetic militias (AOR = 5.78; 95%CI:1. 12,20 .00 ), history of myomectomy(AOR = 5.00;95%CI:1.33,18.73), induction and augmentation of labor (AOR = 2.34;95%:1.15,4.72) obstetric procedure (AOR = 2.54;95%: 1.09,5.91), previous caesarian deliveries 4.90 (2.13,11.26) were found to be significantly associated with uterine rupture. CONCLUSION: This finding showed that the prevalence of uterine rupture is higher. A more vigilant approach to prevent prolonged and obstructed labor, use of partograph, quick referral to a well-equipped center and prevention of other obstetrics complications need to be focused on

A Genetic Analysis of the Relationship Between Life-history Variation and Heat-shock Tolerance in Drosophila buzzatii

Although exposure to environmental stress is common in most populations, and the physiological effects of stress on individuals are well studied, the evolutionary importance of stress to populations is not well understood. To address multitrait responses to environmental change and potential constraints on character evolution, we analysed, in 100 isofemale lines of Drosophila buzzatii, the genetic relationships between resistance to a short heat shock and several life-history traits: survival in benign conditions, larval developmental time, fecundity and longevity. Estimates of heritability of larval thermotolerance were low, but significant, and all life-history traits varied significantly among isofemale lines. Several of these traits covaried significantly. Most correlations indicated positive life-history relationships, but males and females from lines where female fecundity was higher developed more slowly in the absence of stress, which is a negative life-history relationship. The stress reduced or negated many trait associations, and showed one additional relationship; more larvae from lines that developed fast at 25°C survived to adult after stress than did larvae from slow developing lines. These shifts in fitness relationships, when a single stress bout is applied, suggest that even small increases in environmental stress can have profound effects on evolutionary relationships among life-history traits

Joining the conspiracy? Negotiating ethics and emotions in researching (around) AIDS in southern Africa

AIDS is an emotive subject, particularly in southern Africa. Among those who have been directly affected by the disease, or who perceive themselves to be personally at risk, talking about AIDS inevitably arouses strong emotions - amongst them fear, distress, loss and anger. Conventionally, human geography research has avoided engagement with such emotions. Although the ideal of the detached observer has been roundly critiqued, the emphasis in methodological literature on 'doing no harm' has led even qualitative researchers to avoid difficult emotional encounters. Nonetheless, research is inevitably shaped by emotions, not least those of the researchers themselves. In this paper, we examine the role of emotions in the research process through our experiences of researching the lives of 'Young AIDS migrants' in Malawi and Lesotho. We explore how the context of the research gave rise to the production of particular emotions, and how, in response, we shaped the research, presenting a research agenda focused more on migration than AIDS. This example reveals a tension between universalised ethics expressed through ethical research guidelines that demand informed consent, and ethics of care, sensitive to emotional context. It also demonstrates how dualistic distinctions between reason and emotion, justice and care, global and local are unhelpful in interpreting the ethics of research practice

Vitamin D and subsequent all-age and premature mortality: a systematic review

<br>Background: All-cause mortality in the population < 65 years is 30% higher in Glasgow than in equally deprived Liverpool and Manchester. We investigated a hypothesis that low vitamin D in this population may be associated with premature mortality via a systematic review and meta-analysis.</br> <br>Methods: Medline, EMBASE, Web of Science, the Cochrane Library and grey literature sources were searched until February 2012 for relevant studies. Summary statistics were combined in an age-stratified meta-analysis.</br> <br>Results: Nine studies were included in the meta-analysis, representing 24,297 participants, 5,324 of whom died during follow-up. The pooled hazard ratio for low compared to high vitamin D demonstrated a significant inverse association (HR 1.19, 95% CI 1.12-1.27) between vitamin D levels and all-cause mortality after adjustment for available confounders. In an age-stratified meta-analysis, the hazard ratio for older participants was 1.25 (95% CI 1.14-1.36) and for younger participants 1.12 (95% CI 1.01-1.24).</br> <br>Conclusions: Low vitamin D status is inversely associated with all-cause mortality but the risk is higher amongst older individuals and the relationship is prone to residual confounding. Further studies investigating the association between vitamin D deficiency and all-cause mortality in younger adults with adjustment for all important confounders (or using randomised trials of supplementation) are required to clarify this relationship.</br&gt

Adaptive Filtering Enhances Information Transmission in Visual Cortex

Sensory neuroscience seeks to understand how the brain encodes natural environments. However, neural coding has largely been studied using simplified stimuli. In order to assess whether the brain's coding strategy depend on the stimulus ensemble, we apply a new information-theoretic method that allows unbiased calculation of neural filters (receptive fields) from responses to natural scenes or other complex signals with strong multipoint correlations. In the cat primary visual cortex we compare responses to natural inputs with those to noise inputs matched for luminance and contrast. We find that neural filters adaptively change with the input ensemble so as to increase the information carried by the neural response about the filtered stimulus. Adaptation affects the spatial frequency composition of the filter, enhancing sensitivity to under-represented frequencies in agreement with optimal encoding arguments. Adaptation occurs over 40 s to many minutes, longer than most previously reported forms of adaptation.Comment: 20 pages, 11 figures, includes supplementary informatio

The functional response of a generalist predator

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