Programa Nacional de Vigilância da Gripe: relatório da época 2015/2016

O vírus da gripe é uma das maiores causas de morbilidade e mortalidade em todo o mundo, afetando um elevado número de indivíduos em cada ano. Em Portugal a vigilância epidemiológica da gripe é assegurada pelo Programa Nacional de Vigilância da Gripe (PNVG), através da integração da informação das componentes clínica e virológica, gerando informação detalhada relativamente à atividade gripal. A componente clínica é suportada pela Rede Médicos-Sentinela e tem um papel especialmente relevante por possibilitar o cálculo de taxas de incidência permitindo descrever a intensidade e evolução da epidemia de gripe. A componente virológica tem por base o diagnóstico laboratorial do vírus da gripe e tem como objetivos a deteção e caraterização dos vírus da gripe em circulação. Para o estudo mais completo da etiologia da síndrome gripal foi efectuado o diagnóstico diferencial de outros vírus respiratórios: vírus sincicial respiratório tipo A (RSV A) e B (RSV B), o rhinovírus humano (hRV), o vírus parainfluenza humano tipo 1 (PIV1), 2 (PIV2) e 3 (PIV3), o coronavírus humano (hCoV), o adenovírus (AdV) e o metapneumovirus humano (hMPV). Desde 2009 a vigilância da gripe conta também com a Rede Portuguesa de Laboratórios para o Diagnóstico da Gripe que atualmente é constituída por 15 hospitais onde se realiza o diagnóstico laboratorial da gripe. A informação obtida nesta Rede Laboratorial adiciona ao PNVG dados relativos a casos de doença respiratória mais severa com necessidade de internamento. Em 2011/2012, foi lançado um estudo piloto para vigiar os casos graves de gripe admitidos em Unidades de Cuidados Intensivos (UCI) que deu origem à atual Rede de vigilância da gripe em UCI constituída em 2015/2016 por 31 UCI (324 camas). Esta componente tem como objetivo a monitorização de novos casos de gripe confirmados laboratorialmente e admitidos em UCI, permitindo a avaliação da gravidade da doença associada à infeção pelo vírus da gripe. O Sistema da Vigilância Diária da Mortalidade constitui uma componente do PNVG que permite monitorizar a mortalidade semanal por “todas as causas” durante a época de gripe. É um sistema de vigilância epidemiológica que pretende detetar e estimar de forma rápida os impactos de eventos ambientais ou epidémicos relacionados com excessos de mortalidade. A notificação de casos de Síndrome Gripal (SG) e a colheita de amostras biológicas foi realizada em diferentes redes participantes do PNVG: Rede de Médicos-Sentinela, Rede de Serviços de Urgência/Obstetrícia, médicos do Projeto EuroEVA, Rede Portuguesa de Laboratórios para o Diagnóstico da Gripe e Rede vigilância da gripe em UCI. Na época de vigilância da gripe de 2015/2016 foram notificados 1.273 casos de SG, 87% dos quais acompanhados de um exsudado da nasofaringe para diagnóstico laboratorial. No inverno de 2015/2016 observou-se uma atividade gripal de baixa intensidade. O período epidémico ocorreu entre a semana 53/2015 e a semana 8/2016 e o valor mais elevado da taxa de incidência semanal de SG (72,0/100000) foi observado na semana 53/2015. De acordo com os casos notificados à Rede Médicos-Sentinela, o grupo etário dos 15 aos 64 anos foi o que apresentou uma incidência cumulativa mais elevada. O vírus da gripe foi detetado em 41,0% dos exsudados da nasofaringe recebidos tendo sido detetados outros vírus respiratórios em 24% destes. O vírus da gripe A(H1)pdm09 foi o predominantemente detetado em 90,4% dos casos de gripe. Foram também detetados outros vírus da gripe, o vírus B - linhagem Victoria (8%), o vírus A(H3) (1,3%) e o vírus B- linhagem Yamagata (0,5%). A análise antigénica dos vírus da gripe A(H1)pdm09 mostrou a sua semelhança com a estirpe vacinal 2015/2016 (A/California/7/2009), a maioria dos vírus pertencem ao novo grupo genético 6B.1, que foi o predominantemente detetado em circulação na Europa. Os vírus do tipo B apesar de detetados em número bastante mais reduzido comparativamente com o subtipo A(H1)pdm09, foram na sua maioria da linhagem Victoria que antigenicamente se distinguem da estirpe vacinal de 2015/2016 (B/Phuket/3073/2013). Esta situação foi igualmente verificada nos restantes países da Europa, Estados Unidos da América e Canadá. Os vírus do subtipo A(H3) assemelham-se antigenicamente à estirpe selecionada para a vacina de 2016/2017 (A/Hong Kong/4801/2014). Geneticamente a maioria dos vírus caraterizados pertencem ao grupo 3C.2a, e são semelhantes à estirpe vacinal para a época de 2016/2017. A avaliação da resistência aos antivirais inibidores da neuraminidase, não revelou a circulação de estirpes com diminuição da suscetibilidade aos inibidores da neuraminidase (oseltamivir e zanamivir). A situação verificada em Portugal é semelhante à observada a nível europeu. A percentagem mais elevada de casos de gripe foi verificada nos indivíduos com idade inferior a 45 anos. A febre, as cefaleias, o mal-estar geral, as mialgias, a tosse e os calafrios mostraram apresentar uma forte associação à confirmação laboratorial de um caso de gripe. Foi nos doentes com imunodeficiência congénita ou adquirida que a proporção de casos de gripe foi mais elevada, seguidos dos doentes com diabetes e obesidade. A percentagem total de casos de gripe em mulheres grávidas foi semelhante à observada nas mulheres em idade fértil não grávidas. No entanto, o vírus da gripe do tipo A(H1)pdm09 foi detetado em maior proporção nas mulheres grávidas quando comparado as mulheres não grávidas. A vacina como a principal forma de prevenção da gripe é especialmente recomendada em indivíduos com idade igual ou superior a 65 anos, doentes crónicos e imunodeprimidos, grávidas e profissionais de saúde. A vacinação antigripal foi referida em 13% dos casos notificados. A deteção do vírus da gripe ocorreu em 25% dos casos vacinados e sujeitos a diagnóstico laboratorial estando essencialmente associados ao vírus da gripe A(H1)pdm09, o predominante na época de 2015/2016. Esta situação foi mais frequentemente verificada em indivíduos com idade compreendida entre os 15 e 45 anos. A confirmação de gripe em indivíduos vacinados poderá estar relacionada com uma moderada efetividade da vacina antigripal na população em geral. A informação relativa à terapêutica antiviral foi indicada em 67% casos de SG notificados, proporção superior ao verificado em anos anteriores. Os antivirais foram prescritos a um número reduzido de doentes (9,0%) dos quais 45.0% referiam pelo menos a presença de uma doença crónica ou gravidez. O antiviral mais prescrito foi o oseltamivir. A pesquisa de outros vírus respiratórios nos casos de SG negativos para o vírus da gripe, veio revelar a circulação e o envolvimento de outros agentes virais respiratórios em casos de SG. Os vírus respiratórios foram detetados durante todo o período de vigilância da gripe, entre a semana 40/2015 e a semana 20/2016. O hRV, o hCoV e o RSV foram os agentes mais frequentemente detetados, para além do vírus da gripe, estando o RSV essencialmente associado a crianças com idade inferior a 4 anos de idade e o hRV e o hCoV aos adultos e população mais idosa (≥ 65 anos). A Rede Portuguesa de Laboratórios para o Diagnóstico da Gripe, efetuou o diagnóstico da gripe em 7443 casos de infeção respiratória sendo o vírus da gripe detetado em 1458 destes casos. Em 71% dos casos de gripe foi detetado o vírus da gripe A(H1)pdm09. Os vírus da gripe do tipo A(H3) foram detetados esporadicamente e em número muito reduzido (2%), e em 11% o vírus da gripe A (não subtipado). O vírus da gripe do tipo B foi detetado em 16% dos casos. A frequência de cada tipo e subtipo do vírus da gripe identificados na Rede Hospitalar assemelha-se ao observado nos cuidados de saúde primários (Rede Médicos-Sentinela e Serviços de Urgência). Foi nos indivíduos adultos, entre os 45-64 anos, que o vírus A(H1)pdm09 representou uma maior proporção dos casos de gripe incluindo igualmente a maior proporção de doentes que necessitaram de internamento hospitalar em unidades de cuidados intensivos. O vírus da gripe do tipo B esteve associado a casos de gripe confirmados nas crianças entre os 5 e 14 anos. Outros vírus respiratórios foram igualmente detetados sendo o RSV e os picornavírus (hRV, hEV e picornavírus) os mais frequentes e em co circulação com o vírus da gripe. Durante a época de vigilância da gripe, 2015/2016, não se observaram excessos de mortalidade semanais. Nas UCI verificou-se uma franca dominância do vírus da gripe A(H1)pdm09 (90%) e a circulação simultânea do vírus da gripe B (3%). A taxa de admissão em UCI oscilou entre 5,8% e 4,7% entre as semanas 53 e 12 tendo o valor máximo sido registado na semana 8 de 2016 (8,1%). Cerca de metade dos doentes tinha entre 45 e 64 anos. Os mais idosos (65+ anos) foram apenas 20% dos casos, o que não será de estranhar, considerando que o vírus da gripe A(H1)pdm09 circulou como vírus dominante. Aproximadamente 70% dos doentes tinham doença crónica subjacente, tendo a obesidade sido a mais frequente (37%). Comparativamente com a pandemia, em que circulou também o A(H1)pdm09, a obesidade, em 2015/2016, foi cerca de 4 vezes mais frequente (9,8%). Apenas 8% dos doentes tinha feito a vacina contra a gripe sazonal, apesar de mais de 70% ter doença crónica subjacente e de haver recomendações da DGS nesse sentido. A taxa de letalidade foi estimada em 29,3%, mais elevada do que na época anterior (23,7%). Cerca de 80% dos óbitos ocorreram em indivíduos com doença crónica subjacente que poderá ter agravado o quadro e contribuído para o óbito. Salienta-se a ausência de dados históricos publicados sobre letalidade em UCI, para comparação. Note-se que esta estimativa se refere a óbitos ocorridos apenas durante a hospitalização na UCI e que poderão ter ocorrido mais óbitos após a alta da UCI para outros serviços/enfermarias. Este sistema de vigilância da gripe sazonal em UCI poderá ser aperfeiçoado nas próximas épocas reduzindo a subnotificação e melhorando o preenchimento dos campos necessários ao estudo da doença. A época de vigilância da gripe 2015/2016 foi em muitas caraterísticas comparável ao descrito na maioria dos países europeus. A situação em Portugal destacou-se pela baixa intensidade da atividade gripal, pelo predomínio do vírus da gripe do subtipo A(H1)pdm09 acompanhada pela deteção de vírus do tipo B (linhagem Victoria) essencialmente no final da época gripal. A mortalidade por todas as causas durante a epidemia da gripe manteve-se dentro do esperado, não tendo sido observados excessos de mortalidade. Os vírus da gripe do subtipo predominante na época 2015/2016, A(H1)pdm09, revelaram-se antigénicamente semelhantes à estirpe vacinal. Os vírus da gripe do tipo B detetados distinguem-se da estirpe vacinal de 2015/2016. Este facto conduziu à atualização da composição da vacina antigripal para a época 2016/2017. A monitorização contínua da epidemia da gripe a nível nacional e mundial permite a cada inverno avaliar o impacto da gripe na saúde da população, monitorizar a evolução dos vírus da gripe e atuar de forma a prevenir e implementar medidas eficazes de tratamento da doença, especialmente quando esta se apresenta acompanhada de complicações graves.

Statistical analyses of weigh-in-motion data for bridge live load development

This paper discusses the statistical analyses used to derive bridge live loads models for Hong Kong from a 10-year weigh-in-motion (WIM) data. The statistical concepts required and the terminologies adopted in the development of bridge live load models are introduced. This paper includes studies for representative vehicles from the large amount of WIM data in Hong Kong. Different load affecting parameters such as gross vehicle weights, axle weights, axle spacings, average daily number of trucks etc are first analyzed by various stochastic processes in order to obtain the mathematical distributions of these parameters. As a prerequisite to determine accurate bridge design loadings in Hong Kong, this study not only takes advantages of code formulation methods used internationally but also presents a new method for modelling collected WIM data using a statistical approach.

Physical activity, sedentary behavior and total wellness changes among sedentary adults : a 4-week randomized controlled trial

Background The construct of total wellness includes a holistic approach to the body, mind and spirit components of life. While the health benefits of reducing sedentary behavior and increasing physical activity are well documented, little is known about the influence on total wellness of an internet-based physical activity monitor designed to help people to achieve higher physical activity levels. Purpose The purpose of this four-week, personal activity monitor-based intervention program was to reduce sedentary behavior and increase physical activity levels in daily living for sedentary adults and to determine if these changes would also be associated with improvement in total wellness. Methods Twenty-two men and 11 women (27 years ± 4.0) were randomly assigned to either an intervention (n = 18) or control group (n = 15). The intervention group interacted with an online personal activity monitor (Gruve Solution™) designed to reduce sedentary time and increase physical activity during activities of daily living. The control group did not interact with the monitor, as they were asked to follow their normal daily physical activities and sedentary behavior routines. The Wellness Evaluation of Lifestyle (WEL) inventory was used to assess total wellness. Sedentary time, light, walking, moderate and vigorous intensity physical activities were assessed for both intervention and control groups at baseline and at week-4 by the 7-day Sedentary and Light Intensity Physical Activity Log (7-day SLIPA Log) and the International Physical Activity Questionnaire (IPAQ). Results Significant increases in pre-post total wellness scores (from 64% ± 5.7 to 75% ± 8.5) (t (17) = -6.5, p < 0.001) were observed in the intervention group by the end of week four. Intervention participants decreased their sedentary time (21%, 2.3 hours/day) and increased their light (36.7%, 2.5 hours/day), walking (65%, 1057 MET-min/week), moderate (67%, 455 MET-min/week) and vigorous intensity (60%, 442 MET-min/week) physical activity (all p < 0.001). No significant differences for total wellness were observed between the groups at baseline and no pre-post significant differences were observed for any outcome variable in the control group. Conclusion Total wellness is improved when sedentary, but sufficiently physically active adults, reduce sedentary time and increase physical activity levels (i.e. light, walking, moderate and vigorous).

Fracture load for short versus standard cemented hip stems : an experimental in vitro study

Introduction: In an attempt to reduce stress shielding in the proximal femur multiple new shorter stem design have become available. We investigated the load to fracture of a new polished tapered cemented short stem in comparison to the conventional polished tapered Exeter stem. Method: A total of forty-two stems, twenty-one short stems and twenty-one conventional stems both with three different offsets were cemented in a composite sawbone model and loaded to fracture. Results: study showed that femurs will break at a significantly lower load to failure with a shorter compared to conventional length Exeter stem. Conclusion: This Both standard and short stem design are safe to use as the torque to failure is 7–10 times as much as the torques seen in activities of daily living.

Load bearing exercises and functional outcome of individuals with transfemoral amputation fitted with OPRA fixation

Individuals with lower limb amputation fitted with an OPRA osseointegrated fixation are facing an extensive rehabilitation program including static load bearing exercises (LBE). The application of a suitable amount of stress stimulates osseointegration and prepares the bone to tolerate the forces and moments that will be incurred during activities of daily living (ADL. At present, the monitoring is typically carried out using a normal bathroom weighing scale. This scale provides information only on the magnitude of the vertical component of the applied force. The moment around the long axis of the fixation when the femur is perpendicular to the ground is not assessed and neither are the components of force and moment generated on the other two axes.

Load applied on a bone-anchored transfemoral prosthesis: characterisation of a prosthesis : a pilot study

The objectives of this study were (A) to record the inner prosthesis loading during activities of daily living (ADL), (B) to present a set of variables comparing loading data, and (C) to provide an example of characterisation of two prostheses. The load was measured at 200 Hz using a multi-axial transducer mounted between the residuum and the knee of an individual with unilateral transfemoral amputation fitted with a bone-anchored prosthesis. The load was measured while using two different prostheses including a mechanically (PRO1) and a microprocessor controlled (PRO2) knee during six ADL. The characterisation of prosthesis was achieved using a set of variables split into four categories, including temporal characteristics, maximum loading, loading slopes and impulse. Approximately 360 gait cycles were analysed for each prosthesis. PRO1 showed a cadence improved by 19% and 7%, a maximum force on the long axis reduced by 11% and 19%, as well as an impulse reduced by 32% and 15% during descent of incline and stairs compared to PRO2, respectively. This work confirmed that the proposed apparatus and characterisation can reveal how changes of prosthetic components are translated into inner loading.

A two-arm cluster randomized control trial to determine the effectiveness of a pressure ulcer prevention bundle for critically ill patients

Purpose This study tested the effectiveness of a pressure ulcer (PU) prevention bundle in reducing the incidence of PUs in critically ill patients in two Saudi intensive care units (ICUs). Design A two-arm cluster randomized experimental control trial. Methods Participants in the intervention group received the PU prevention bundle, while the control group received standard skin care as per the local ICU policies. Data collected included demographic variables (age, diagnosis, comorbidities, admission trajectory, length of stay) and clinical variables (Braden Scale score, severity of organ function score, mechanical ventilation, PU presence, and staging). All patients were followed every two days from admission through to discharge, death, or up to a maximum of 28 days. Data were analyzed with descriptive correlation statistics, Kaplan-Meier survival analysis, and Poisson regression. Findings The total number of participants recruited was 140: 70 control participants (with a total of 728 days of observation) and 70 intervention participants (784 days of observation). PU cumulative incidence was significantly lower in the intervention group (7.14%) compared to the control group (32.86%). Poisson regression revealed the likelihood of PU development was 70% lower in the intervention group. The intervention group had significantly less Stage I (p = 002) and Stage II PU development (p = 026). Conclusions Significant improvements were observed in PU-related outcomes with the implementation of the PU prevention bundle in the ICU; PU incidence, severity, and total number of PUs per patient were reduced. Clinical Relevance Utilizing a bundle approach and standardized nursing language through skin assessment and translation of the knowledge to practice has the potential to impact positively on the quality of care and patient outcome.

Centile reference charts for total energy expenditure in infants from 1 to 12 months

Background: A knowledge of energy expenditure in infancy is required for the estimation of recommended daily amounts of food energy, for designing artificial infant feeds, and as a reference standard for studies of energy metabolism in disease states. Objectives: The objectives of this study were to construct centile reference charts for total energy expenditure (TEE) in infants across the first year of life. Methods: Repeated measures of TEE using the doubly labeled water technique were made in 162 infants at 1.5, 3, 6, 9 and 12 months. In total, 322 TEE measurements were obtained. The LMS method with maximum penalized likelihood was used to construct the centile reference charts. Centiles were constructed for TEE expressed as MJ/day and also expressed relative to body weight (BW) and fat-free mass (FFM). Results: TEE increased with age and was 1.40,1.86, 2.64, 3.07 and 3.65 MJ/day at 1.5, 3, 6, 9 and 12 months, respectively. The standard deviations were 0.43, 0.47, 0.52,0.66 and 0.88, respectively. TEE in MJ/kg increased from 0.29 to 0.36 and in MJ/day/kg FFM from 0.36 to 0.48. Conclusions: We have presented centile reference charts for TEE expressed as MJ/day and expressed relative to BW and FFM in infants across the first year of life. There was a wide variation or biological scatter in TEE values seen at all ages. We suggest that these centile charts may be used to assess and possibly quantify abnormal energy metabolism in disease states in infants.

Sediment concentration prediction and statistical evaluation for annual load estimation

We consider the development of statistical models for prediction of constituent concentration of riverine pollutants, which is a key step in load estimation from frequent flow rate data and less frequently collected concentration data. We consider how to capture the impacts of past flow patterns via the average discounted flow (ADF) which discounts the past flux based on the time lapsed - more recent fluxes are given more weight. However, the effectiveness of ADF depends critically on the choice of the discount factor which reflects the unknown environmental cumulating process of the concentration compounds. We propose to choose the discount factor by maximizing the adjusted R-2 values or the Nash-Sutcliffe model efficiency coefficient. The R2 values are also adjusted to take account of the number of parameters in the model fit. The resulting optimal discount factor can be interpreted as a measure of constituent exhaustion rate during flood events. To evaluate the performance of the proposed regression estimators, we examine two different sampling scenarios by resampling fortnightly and opportunistically from two real daily datasets, which come from two United States Geological Survey (USGS) gaging stations located in Des Plaines River and Illinois River basin. The generalized rating-curve approach produces biased estimates of the total sediment loads by -30% to 83%, whereas the new approaches produce relatively much lower biases, ranging from -24% to 35%. This substantial improvement in the estimates of the total load is due to the fact that predictability of concentration is greatly improved by the additional predictors.

Effects of environmental heat on conception rates in lactating dairy cows: Critical periods of exposure

Environmental heat can reduce conception rates (the proportion of services that result in pregnancy) in lactating dairy cows. The study objectives were to identify periods of exposure relative to the service date in which environmental heat is most closely associated with conception rates, and to assess whether the total time cows are exposed to high environmental heat within each 24-h period is more closely associated with conception rates than is the maximum environmental heat for each 24-h period. A retrospective observational study was conducted in 25 predominantly Holstein-Friesian commercial dairy herds located in Australia. Associations between weather and conception rates were assessed using 16,878 services performed over a 21-mo period. Services were classified as successful based on rectal palpation. Two measures of heat load were defined for each 24-h period: the maximum temperature-humidity index (THI) for the period, and the number of hours in the 24-h period when the THI was >72. Conception rates were reduced when cows were exposed to a high heat load from the day of service to 6 d after service, and in wk -1. Heat loads in wk -3 to -5 were also associated with reduced conception rates. Thus, management interventions to ameliorate the effects of heat load on conception rates should be implemented at least 5 wk before anticipated service and should continue until at least 1 wk after service. High autocorrelations existed between successive daily values in both measures, and associations between day of heat load relative to service day and conception rates differed substantially when ridge regression was used to account for this autocorrelation. This indicates that when assessing the effects of heat load on conception rates, the autocorrelation in heat load between days should be accounted for in analyses. The results suggest that either weekly averages or totals summarizing the daily heat load are adequate to describe heat load when assessing effects on conception rates in lactating dairy cows.

Polybridge Technical Report

This study examined the physical and chemical properties of a novel, fully-recirculated prawn and polychaete production system that incorporated polychaete-assisted sand filters (PASF). The aims were to assess and demonstrate the potential of this system for industrialisation, and to provide optimisations for wastewater treatment by PASF. Two successive seasons were studied at commercially-relevant scales in a prototype system constructed at the Bribie Island Research Centre in Southeast Queensland. The project produced over 5.4 tonnes of high quality black tiger prawns at rates up to 9.9 tonnes per hectare, with feed conversion of up to 1.1. Additionally, the project produced about 930 kg of high value polychaete biomass at rates up to 1.5 kg per square metre of PASF, with the worms feeding predominantly on waste nutrients. Importantly, this closed production system demonstrated rapid growth of healthy prawns at commercially relevant production levels, using methods that appear feasible for application at large scale. Deeper (23 cm) PASF beds provided similar but more reliable wastewater treatment efficacies compared with shallower (13 cm) beds, but did not demonstrate significantly greater polychaete productivity than (easier to harvest) shallow beds. The nutrient dynamics associated with seasonal and tidal operations of the system were studied in detail, providing technical and practical insights into how PASF could be optimised for the mitigation of nutrient discharge. The study also highlighted some of the other important advantages of this integrated system, including low sludge production, no water discharge during the culture phase, high ecosystem health, good prospects for biosecurity controls, and the sustainable production of a fishery-limited resource (polychaetes) that may be essential for the expansion of prawn farming industries throughout the world. Regarding nutrient discharge from this prototype mariculture system, when PASF was operating correctly it proved feasible to have no water (or nutrient) discharge during the entire prawn growing season. However, the final drain harvest and emptying of ponds that is necessary at the end of the prawn farming season released 58.4 kg ha-1 of nitrogen and 6 kg ha-1 of phosphorus (in Season 2). Whilst this is well below (i.e., one-third to one-half of) the current load-based licencing conditions for many prawn farms in Australia, the levels of nitrogen and chlorophyll a in the ponds remained higher than the more-stringent maximum limits at the Bribie Island study site. Zero-net-nutrient discharge was not achieved, but waste nutrients were low where 5.91 kg of nitrogen and 0.61 kg of phosphorus was discharged per tonne of prawns produced. This was from a system that deployed PASF at 14.4% of total ponded farm area which treated an average of 5.8% of pond water daily and did not use settlement ponds or other natural or artificial water remediation systems. Four supplemental appendices complement this research by studying several additional aspects that are central to the industrialisation of PASF. The first details an economic model and decision tool which allows potential users to interactively assess construction and operational variables of PASF at different scales. The second provides the qualitative results of a prawn maturation trial conducted collaboratively with the Commonwealth Scientific and Industrial Research Organisation (CSIRO) to assess dietary inclusions of PASF-produced worms. The third provides the reproductive results from industry-based assessments of prawn broodstock produced using PASF. And the fourth appendix provides detailed elemental and nutritional analyses of bacterial biofilm produced by PASF and assesses its potential to improve the growth of prawns in recirculated culture systems.

Acute renal failure in critically ill patients : With special reference to prediction of outcome

Acute renal failure (ARF) is a clinical syndrome characterized by rapidly decreasing glomerular filtration rate, which results in disturbances in electrolyte- and acid-base homeostasis, derangement of extracellular fluid volume, and retention of nitrogenous waste products, and is often associated with decreased urine output. ARF affects about 5-25% of patients admitted to intensive care units (ICUs), and is linked to high mortality and morbidity rates. In this thesis outcome of critically ill patients with ARF and factors related to outcome were evaluated. A total of 1662 patients from two ICUs and one acute dialysis unit in Helsinki University Hospital were included. In study I the prevalence of ARF was calculated and classified according to two ARF-specific scoring methods, the RIFLE classification and the classification created by Bellomo et al. (2001). Study II evaluated monocyte human histocompatibility leukocyte antigen-DR (HLA-DR) expression and plasma levels of one proinflammatory (interleukin (IL) 6) and two anti-inflammatory (IL-8 and IL-10) cytokines in predicting survival of critically ill ARF patients. Study III investigated serum cystatin C as a marker of renal function in ARF and its power in predicting survival of critically ill ARF patients. Study IV evaluated the effect of intermittent hemodiafiltration (HDF) on myoglobin elimination from plasma in severe rhabdomyolysis. Study V assessed long-term survival and health-related quality of life (HRQoL) in ARF patients. Neither of the ARF-specific scoring methods presented good discriminative power regarding hospital mortality. The maximum RIFLE score for the first three days in the ICU was an independent predictor of hospital mortality. As a marker of renal dysfunction, serum cystatin C failed to show benefit compared with plasma creatinine in detecting ARF or predicting patient survival. Neither cystatin C nor plasma concentrations of IL-6, IL-8, and IL-10, nor monocyte HLA-DR expression were clinically useful in predicting mortality in ARF patients. HDF may be used to clear myoglobin from plasma in rhabdomyolysis, especially if the alkalization of diuresis does not succeed. The long-term survival of patients with ARF was found to be poor. The HRQoL of those who survive is lower than that of the age- and gender-matched general population.

Multi-site downscaling of maximum and minimum daily temperature using support vector machine

Climate change impact assessment studies involve downscaling large-scale atmospheric predictor variables (LSAPVs) simulated by general circulation models (GCMs) to site-scale meteorological variables. This article presents a least-square support vector machine (LS-SVM)-based methodology for multi-site downscaling of maximum and minimum daily temperature series. The methodology involves (1) delineation of sites in the study area into clusters based on correlation structure of predictands, (2) downscaling LSAPVs to monthly time series of predictands at a representative site identified in each of the clusters, (3) translation of the downscaled information in each cluster from the representative site to that at other sites using LS-SVM inter-site regression relationships, and (4) disaggregation of the information at each site from monthly to daily time scale using k-nearest neighbour disaggregation methodology. Effectiveness of the methodology is demonstrated by application to data pertaining to four sites in the catchment of Beas river basin, India. Simulations of Canadian coupled global climate model (CGCM3.1/T63) for four IPCC SRES scenarios namely A1B, A2, B1 and COMMIT were downscaled to future projections of the predictands in the study area. Comparison of results with those based on recently proposed multivariate multiple linear regression (MMLR) based downscaling method and multi-site multivariate statistical downscaling (MMSD) method indicate that the proposed method is promising and it can be considered as a feasible choice in statistical downscaling studies. The performance of the method in downscaling daily minimum temperature was found to be better when compared with that in downscaling daily maximum temperature. Results indicate an increase in annual average maximum and minimum temperatures at all the sites for A1B, A2 and B1 scenarios. The projected increment is high for A2 scenario, and it is followed by that for A1B, B1 and COMMIT scenarios. Projections, in general, indicated an increase in mean monthly maximum and minimum temperatures during January to February and October to December.

Distributed Load Control in Multiphase Radial Networks

The current power grid is on the cusp of modernization due to the emergence of distributed generation and controllable loads, as well as renewable energy. On one hand, distributed and renewable generation is volatile and difficult to dispatch. On the other hand, controllable loads provide significant potential for compensating for the uncertainties. In a future grid where there are thousands or millions of controllable loads and a large portion of the generation comes from volatile sources like wind and solar, distributed control that shifts or reduces the power consumption of electric loads in a reliable and economic way would be highly valuable.

Load control needs to be conducted with network awareness. Otherwise, voltage violations and overloading of circuit devices are likely. To model these effects, network power flows and voltages have to be considered explicitly. However, the physical laws that determine power flows and voltages are nonlinear. Furthermore, while distributed generation and controllable loads are mostly located in distribution networks that are multiphase and radial, most of the power flow studies focus on single-phase networks.

This thesis focuses on distributed load control in multiphase radial distribution networks. In particular, we first study distributed load control without considering network constraints, and then consider network-aware distributed load control.

Distributed implementation of load control is the main challenge if network constraints can be ignored. In this case, we first ignore the uncertainties in renewable generation and load arrivals, and propose a distributed load control algorithm, Algorithm 1, that optimally schedules the deferrable loads to shape the net electricity demand. Deferrable loads refer to loads whose total energy consumption is fixed, but energy usage can be shifted over time in response to network conditions. Algorithm 1 is a distributed gradient decent algorithm, and empirically converges to optimal deferrable load schedules within 15 iterations.

We then extend Algorithm 1 to a real-time setup where deferrable loads arrive over time, and only imprecise predictions about future renewable generation and load are available at the time of decision making. The real-time algorithm Algorithm 2 is based on model-predictive control: Algorithm 2 uses updated predictions on renewable generation as the true values, and computes a pseudo load to simulate future deferrable load. The pseudo load consumes 0 power at the current time step, and its total energy consumption equals the expectation of future deferrable load total energy request.

Network constraints, e.g., transformer loading constraints and voltage regulation constraints, bring significant challenge to the load control problem since power flows and voltages are governed by nonlinear physical laws. Remarkably, distribution networks are usually multiphase and radial. Two approaches are explored to overcome this challenge: one based on convex relaxation and the other that seeks a locally optimal load schedule.

To explore the convex relaxation approach, a novel but equivalent power flow model, the branch flow model, is developed, and a semidefinite programming relaxation, called BFM-SDP, is obtained using the branch flow model. BFM-SDP is mathematically equivalent to a standard convex relaxation proposed in the literature, but numerically is much more stable. Empirical studies show that BFM-SDP is numerically exact for the IEEE 13-, 34-, 37-, 123-bus networks and a real-world 2065-bus network, while the standard convex relaxation is numerically exact for only two of these networks.

Theoretical guarantees on the exactness of convex relaxations are provided for two types of networks: single-phase radial alternative-current (AC) networks, and single-phase mesh direct-current (DC) networks. In particular, for single-phase radial AC networks, we prove that a second-order cone program (SOCP) relaxation is exact if voltage upper bounds are not binding; we also modify the optimal load control problem so that its SOCP relaxation is always exact. For single-phase mesh DC networks, we prove that an SOCP relaxation is exact if 1) voltage upper bounds are not binding, or 2) voltage upper bounds are uniform and power injection lower bounds are strictly negative; we also modify the optimal load control problem so that its SOCP relaxation is always exact.

To seek a locally optimal load schedule, a distributed gradient-decent algorithm, Algorithm 9, is proposed. The suboptimality gap of the algorithm is rigorously characterized and close to 0 for practical networks. Furthermore, unlike the convex relaxation approach, Algorithm 9 ensures a feasible solution. The gradients used in Algorithm 9 are estimated based on a linear approximation of the power flow, which is derived with the following assumptions: 1) line losses are negligible; and 2) voltages are reasonably balanced. Both assumptions are satisfied in practical distribution networks. Empirical results show that Algorithm 9 obtains 70+ times speed up over the convex relaxation approach, at the cost of a suboptimality within numerical precision.

SUNLIGHT: a computer program for calculation of daily solar radiation

This paper presents an algorithm and software (available from ICLARM) for estimating the possible amount of sunlight that may fall on any location of the earth, any day of the year, as might be required for ecological modelling.