443 research outputs found
Optimal control of fan coil battery air and water flow rates requiring minimal on-line measurements
Abstract Fan coil units are widely used in air-conditioning systems for heating and cooling of commercial buildings. Control - capable of achieving better operational efficiencies and at the same time, guarantying thermal comfort - is paramount in order to achieve optimal operation. The present paper presents a novel generalised control strategy, requiring only minimal input data, for optimising fan speed in order to reduce. Different control models are implemented to predict fan coil capacities and associated total power consumption. The developed strategy has been compared to fixed speed and benchmark fan speed control strategies, using both a steady state and a quasi-steady state algorithm, for various building loads. Results show average reduction in fan coil battery power consumption of 34% and 43% in heating and cooling mode respectively, when the optimal control is compared to fixed fan speed settings. Savings between 4.9% and 9.1% can be achieved by the control algorithms if compared to the benchmark fan speed control strategies
Trends in outpatient malaria cases, following Mass Long Lasting Insecticidal Nets (LLIN) distribution in epidemic prone and endemic areas of Kenya
Background: There were over 6 million case of malaria reported in Kenya in 2015 and it remains a major public health priority despite significant investments in interventions to control and prevent infections in high risk areas.Objectives: To analyse trends from 2011-2015, and report i) outpatient department (OPD) malaria case prevalence, ii) the proportion of confirmed malaria cases of all OPD cases stratified by age category, and iii) the proportion of the population potentially protected by long-lasting insecticidal nets (LLINs), following mass distribution of LLINs in malaria epidemic prone and endemic areas.Design: A retrospective study.Setting: Kenya’s Coast endemic, Lake endemic and Highland epidemic zones.Subjects: All outpatient malaria cases reported in the District Health Information System.Results: The proportion of people who received mass LLINs ranged from 80-95% in epidemic prone and endemic areas of Kenya. The coastal endemic zone had the lowest number of reported malaria cases at almost 840,000 in 2011, compared with the lake endemic zone which reported 4.3 million total cases. Confirmed malaria cases of all the OPD morbidity increased by 1%, 20% and 4% in the Highland epidemic prone, the Lake and Coast endemic region in 2011 to 2015, respectively. There was a trend towards fewer cases across all three high risk regions from 2012-2013, but this reversed with increasing cases being reported in 2014-2015.Conclusion: Despite a high LLIN coverage malaria cases increased over time. There is need for patient-level studies to assess if LLINs are being used appropriately and to look towards other complimentary malaria prevention strategies
Trends of reported outpatient malaria cases to assess the Test, Treat and Track (T3) policy in Kenya
Background: Kenya reports over six million malaria cases annually. In 2012 the country adopted the Test, Treat and Track (T3) policy to ensure that all suspected malaria cases are tested, confirmed cases are treated with quality-assured drugs and timely accurate malaria surveillance are in place to guide policy and practice.Objective: To describe the trends of confirmed outpatient malaria cases and the consumption of artemisinin-based combination therapy (ACT) in the government health facilities in Kenya following the roll out of the T3 initiative.Design: A retrospective review study.Setting: All government health facilities in the 47 counties.Subjects: Secondary data on all outpatient malaria cases and ACT consumed as reported in the District Helth Information Software (DHIS).Results: Total malaria cases decreased from 8.5 to 6.8million cases in 2012 and 2015, respectively. Confirmed malaria cases increased from 1.97 (23%) to 4.9 (72%) million cases. The greatest decrease in total malaria cases and the greatest rise in confirmation of suspected cases occurred in the lower level health facilities. More confirmation of suspected cases occurred in the malaria endemic regions compared to other epidemiological zones. Excess ACT consumption reduced by 46% to reach 27% in 2015.Conclusion: Though there was increased confirmation of suspected malaria, still onethird of the outpatients were treated clinically in 2015. About one-third of ACTs were also used in excess in 2015. There is need for enhanced efforts to adhere to the T3 policy and malaria elimination guidelines
Intermittent preventive treatment and bed nets uptake among pregnant women in Kenya
Background: Malaria in pregnancy is a preventable disease which results in poor pregnancy outcomes. The use of intermittent preventive treatment in pregnancy (IPTp) and long-lasting insecticide treated nets (LLINs) have been shown to reduce maternal malaria episodes.Objectives: To describe i) The proportion receiving first and second dose (IPTp1 and 2) in malaria endemic zones, ii) proportion receiving IPTp 1 and 2 stratified by coast and lake endemic zones iii) proportion receiving LLINs, stratified by coastal and lake endemic zones.Design: A retrospective descriptive study.Setting: Lake and Coast region malaria endemic zones.Subjects: Pregnant women.Results: IPTp2 dose during an ANC revisit fell by 29% between 2012 and 2015, with 76% receiving an IPTp2 in 2012 and only 47% receiving it in 2015. More pregnant women in Coastal endemic areas received IPTp2 compared to Lake, with 88% versus 73% in 2012, and 53% versus 44% in 2015, respectively.There was steady increase in bed net usage from 69% and 54% in 2012 to 96% and 95% in 2015 for lake and coast endemic zones respectively. The uptake of LLINs was 15% higher in the lake region compared to the coastal endemic region in 2012 and significantly declined over the five years to 6%, 7% and 1% in 2013, 2014 and 2015, respectively.Conclusion: Our study found that there has been a significant decline from 2012 through 2015, in the number of pregnant women in Kenya receiving recommended malaria prophylaxis in the regions of highest malaria burden. However, the coverage of LLIN has consistently improved over the same period
Editorial: Structured operational research and training in the public health sector: the Kenyan experience
No Abstrac
Spatial distribution and co-infection with urogenital and intestinal schistosomiasis among primary school children in Migori County, Kenya
Background: Schistosomiasis is the most prevalent helminthic infection in sub-Saharan Africa. School age children have the highest burden. Chronic schistosome infections in children can have irreversible effects lasting throughout adulthood.Objective: To determine the prevalence, intensity and distribution of urogenital and intestinal schistosomiasis among primary school children in Migori County, Kenya.Design: Descriptive cross-sectional study.Setting: Primary schools in Migori County, Kenya.Subjects: Children aged seven to fourteen years.Results: We enrolled 1,784 children with the ratio of female to males being 1:1. Their mean age was 11.4 years (standard deviation ± 1.6). The overall prevalence of infection was 26%, with urogenital and intestinal schistosomiasis being found in 9% and 20% of children, respectively. A trend of increasing prevalence with increasing age of children was observed. Boys had a 50% higher risk of being infected with schistosomiasis when compared to girls (adjusted odds ratio 1.5, 95% confidence interval 1.2-1.9). Intensities of schistosome infections did not vary significantly across gender and age. Nyatike Constituency had the highest prevalence of schistosomiasis (54%).Prevalence in schools ranged from 1.7 to 89%. Seven schools (23%) had a schistosomiasis prevalence of at least 50% while 12 (39%) schools had schistosomiasis prevalence of between 10 and 50%.Conclusion: Our study showed that schistosomiasis is endemic in the study area and represents a significant public health problem among school children. The area should be prioritised for interventions including mass deworming, public health education and sanitation improvement
Pilot protocol for the Parent and Infant Inter (X)action Intervention (PIXI) feasibility study
This paper provides the detailed protocol for a pilot study testing the feasibility, acceptability, and initial efficacy of a targeted two-phase, remotely delivered early intervention program for infants with neurogenetic conditions (NGC) and their caregivers. The Parent and Infant Inter(X)action Intervention (PIXI) is designed to support parents and infants with a NGC diagnosed in the first year of life. PIXI is implemented in two phases, with the first phase focusing on psychoeducation, parent support, and how to establish routines for supporting infant development. Phase II helps parents learn targeted skills to support their infant's development as symptoms may begin to emerge. The proposed non-randomized feasibility pilot study will establish the feasibility of a year-long virtually implemented intervention program to support new parents of an infant diagnosed with an NGC
A quasi-steady state mathematical model of an integrated ground source heat pump for building space control
[EN] This paper is concerned with the development of a mathematical model, capable of describing the quasisteady
state performance of an integrated ground source heat pump, which is used for heating and
cooling of an institutional building located in a Mediterranean climate. The model is structured on functional
basis according to the heat pump vapour compression or primary circuit, a secondary ground loop
circuit and a secondary building loop circuit. Heat pump heating and cooling capacities, as well as COP,
are considered to be dependent variables and are estimated in the model using performance fitted maps.
Independent variables include: compressor speed, circulation pump speeds, ground loop return temperature
and building circuit return temperature. The model is validated using data from a full-scale ground
source heat pump installation. The validated model is used to examine system capacity and performance
sensitivity to different control optimisation strategies, including set-point control of room air temperature,
room air bandwidth temperature, building loop return water temperature and building loop return
bandwidth temperature.This work was supported under the FP7 programme Advanced ground source heat pump systems for heating and cooling in Mediterranean climates (GROUND-MED FP7-ENERGY-2007-2-TREN-218895)Corberán Salvador, JM.; Finn, D.; Montagud Montalvá, CI.; Murphy, F.; Edwards, K. (2011). A quasi-steady state mathematical model of an integrated ground source heat pump for building space control. Energy and Buildings. 43(1):82-92. https://doi.org/10.1016/j.enbuild.2010.08.017S829243
Chiral Analysis of Quenched Baryon Masses
We extend to quenched QCD an earlier investigation of the chiral structure of
the masses of the nucleon and the delta in lattice simulations of full QCD.
Even after including the meson-loop self-energies which give rise to the
leading and next-to-leading non-analytic behaviour (and hence the most rapid
variation in the region of light quark mass), we find surprisingly little
curvature in the quenched case. Replacing these meson-loop self-energies by the
corresponding terms in full QCD yields a remarkable level of agreement with the
results of the full QCD simulations. This comparison leads to a very good
understanding of the origins of the mass splitting between these baryons.Comment: 23 pages, 6 figure
A Lattice Study of the Nucleon Excited States with Domain Wall Fermions
We present results of our numerical calculation of the mass spectrum for
isospin one-half and spin one-half non-strange baryons, i.e. the ground and
excited states of the nucleon, in quenched lattice QCD. We use a new lattice
discretization scheme for fermions, domain wall fermions, which possess almost
exact chiral symmetry at non-zero lattice spacing. We make a systematic
investigation of the negative-parity spectrum by using two distinct
interpolating operators at on a
lattice. The mass estimates extracted from the two operators are consistent
with each other. The observed large mass splitting between this state,
, and the positive-parity ground state, the nucleon N(939), is well
reproduced by our calculations. We have also calculated the mass of the first
positive-parity excited state and found that it is heavier than the
negative-parity excited state for the quark masses studied.Comment: 46 pages, REVTeX, 11 figures included, revised version accepted for
publication in Phys. Rev.
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