Data on experiments result of three identical huts with shape-stabilized phase change materials in Japanese temperate climate.
ABSTRACT: The data in this article are the experimental results of three identical huts (Hut A, B and C), which were examined by using varying shape-stabilized PCMs (SSPCMs) sheet levels under natural and heating conditions in winter of Chiba prefecture where Japanese temperate climate. The SSPCMs sheet established the melting and solidification-temperature ranged at 19-26?°C were used. In Hut A, no SSPCM sheets were applied; in Hut B, four layers of SSPCM sheets were applied to the floor; in Hut C, one layer of SSPCM was applied to the floor, walls, and ceilings. The data provide information on the application of SSPCM sheets to improve indoor stabilization and the heating load reduction effects.
Project description:The data in this article are the experiment and simulation results of three identical huts were examined using by using varying shape-stabilized PCMs (SSPCMs) sheet levels in winter of Chiba prefecture where Japanese temperate climate. A shape-stabilized phase-change material (SSPCM) established the melting- and solidification-temperature ranges at 19-26?°C was installed on the floor, walls, and ceiling of various buildings, and its effects on indoor room temperature stabilization and heating load reduction were examined using experiments and simulations. The PCM model was developed based on the specific heat capacity measured using a thermostatic chamber and simulations results were obtained using EnergyPlus. The validity of the PCM model was examined by comparing the simulation and experimental results. The model was then examined to determine the applicability of PCM to the various climates in Japan through annual heating load simulations. The target buildings were classified as Type A (no PCM, reference), Type B (only the floor contained PCM), and Type C (the floor, walls, and ceiling contained PCM) using a standard Japanese house. Types B and C had the same amount of PCM. The simulation was run for 21 cases, with one being run for each type of building in seven Japanese climates.
Project description:<h4>Background</h4>Indoor spraying of walls and ceilings with residual insecticide remains a primary method of malaria control. Insecticide resistance in malaria vectors is a growing problem. Novel insecticides for indoor residual spraying (IRS) which can improve the control of pyrethroid resistant malaria vectors are urgently needed. Insecticide mixtures have the potential to improve efficacy or even to manage resistance in some situations but this possibility remains underexplored experimentally. Chlorfenapyr is a novel pyrrole insecticide which has shown potential to improve the control of mosquitoes which are resistant to current WHO-approved insecticides.<h4>Method</h4>The efficacy of IRS with chlorfenapyr applied alone or as a mixture with alpha-cypermeththrin (a pyrethroid) was evaluated in experimental huts in Cove, Southern Benin against wild free flying pyrethroid resistant Anopheles gambiae sl. Comparison was made with IRS with alpha-cypermethrin alone. Fortnightly 30-minute in situ cone bioassays were performed to assess the residual efficacy of the insecticides on the treated hut walls.<h4>Results</h4>Survival rates of wild An gambiae from the Cove hut site in WHO resistance bioassays performed during the trial were >90% with permethrin and deltamethrin treated papers. Mortality of free-flying mosquitoes entering the experimental huts was 4% in the control hut. Mortality with alpha-cypermethrin IRS did not differ from the control (5%, P>0.656). The highest mortality was achieved with chlorfenapyr alone (63%). The alpha-cypermethrin + chlorfenapyr mixture killed fewer mosquitoes than chlorfenapyr alone (43% vs. 63%, P<0.001). While the cone bioassays showed a more rapid decline in residual mortality with chlorfenapyr IRS to <30% after only 2 weeks, fortnightly mortality rates of wild free-flying An gambiae entering the chlorfenapyr IRS huts were consistently high (50-70%) and prolonged, lasting over 4 months.<h4>Conclusion</h4>IRS with chlorfenapyr shows potential to significantly improve the control of malaria transmission in pyrethroid resistant areas compared to pyrethroid IRS or the mixture. Thirty minute in situ cone bioassays are not predictive of the performance of chlorfenapyr IRS under field conditions.
Project description:Insecticides used against Aedes aegypti and other disease vectors can elicit a multitude of dose-dependent effects on behavioral and bionomic traits. Estimating the potential epidemiological impact of a product requires thorough understanding of these effects and their interplay at different dosages. Volatile spatial repellent (SR) products come with an additional layer of complexity due to the potential for altered movement of affected mosquitoes and diffusion of volatile particles of the product beyond the treated house. Here, we propose a paired experimental design and statistical inference framework for estimating these nuanced effects of volatile SRs.We fitted a continuous-time Markov chain model in a Bayesian framework to data on marked mosquitoes released in interconnected experimental huts conducted in Iquitos, Peru. We estimated the effects of two dosages of transfluthrin on Ae. aegypti behaviors associated with human-vector contact: repellency, exiting and knockdown in the treated space and in connected, adjacent huts. We validated the framework using simulated data.The odds of a female Ae. aegypti being repelled, and thus prevented from entering a treated hut (HT), increased at both dosages (low dosage: odds = 1.64, 95% highest density interval (HDI) = 1.30-2.09; high dosage: odds = 1.35, HDI = 1.04-1.67). The relative risk of exiting from the treated hut was reduced (low: RR = 0.70, HDI = 0.62-1.09; high: RR = 0.70, HDI = 0.40-1.06), with this effect carrying over to untreated spaces two huts away from the treated hut (H2) (low: RR = 0.79, HDI = 0.59-1.01; high: RR = 0.66, HDI = 0.50-0.87). Knockdown rates were increased in both treated and downstream huts, particularly under high dosage (HT: RR = 8.37, HDI = 2.11-17.35; H1: RR = 1.39, HDI = 0.52-2.69; H2: RR = 2.22, HDI = 0.96-3.86).Our framework is effective at elucidating multiple effects of volatile chemicals used in SR products, as well as their downstream effects. For the examined formulations of transfluthrin, we found notable dose-dependent effects on repellency, movement and knockdown that carry over to adjacent, untreated spaces.
Project description:The earliest archaeological remains of dwelling huts built by Homo sapiens were found in various European Upper Paleolithic open-air camps. Although floors of huts were found in a small number of cases, modern organization of the home space that includes defined resting areas and bedding remains was not discovered. We report here the earliest in situ bedding exposed on a brush hut floor. It has recently been found at the previously submerged, excellently preserved 23,000-year-old fisher-hunter-gatherers' camp of Ohalo II, situated in Israel on the shore of the Sea of Galilee. The grass bedding consists of bunches of partially charred Puccinellia confer convoluta stems and leaves, covered by a thin compact layer of clay. It is arranged in a repeated pattern, on the floor, around a central hearth. This study describes the bedding in its original context on a well preserved intentionally constructed floor. It also reconstructs on the basis of direct evidence (combined with ethnographic analogies) the Upper Paleolithic hut as a house with three major components: a hearth, specific working locales, and a comfortable sleeping area near the walls.
Project description:BACKGROUND:MAGNet LN is a wash resistant long-lasting insecticidal (polyethylene) net (LLIN) in which the alpha-cypermethrin insecticide is incorporated within the 150 denier high density polyethylene monofilaments of the nets. The bio-efficacy of MAGNet LN was reported to be high even after 25 washes. The LN met the WHO criteria of Phase I evaluation and obtained recommendation from the World Health Organization Pesticide Evaluation Scheme (WHOPES) for Phase II trial. For registration of the LN in India, the current study was conducted to evaluate its efficacy after 20 or 25 washes compared to negative control (untreated net) and positive control (Duranet LN) in experimental huts against a wild, free flying pyrethroid susceptible population of Anopheles fluviatilis in terms of deterrence, blood-feeding inhibition, mortality and induced exophily. METHODS:The evaluation was carried out in six experimental huts located at Kandhaguda village in Malkangiri district, Odisha state following the WHO guidelines. RESULTS:The study showed that 25 times washed MAGNet LN produced 100% mortality in cone bioassays before and after hut evaluation. MAGNet washed 25 times did not differ significantly from all other treated nets in terms of deterring hut entry, induced exophily, blood feeding inhibition and causing mortality of An. fluviatilis. CONCLUSIONS:MAGNet LN showed extended wash resistance retaining its bio-efficacy up to 25 washes and met the WHOPES requirement of passing Phase II evaluation.
Project description:<h4>Background</h4>Baited traps are potential tools for removal or surveillance of disease vectors. To optimize the use of counter-flow traps baited with human odor (nylon socks that had been worn for a single day) to capture wild mosquitoes in the Gambia, investigations were conducted at a field experimental site.<h4>Methodology/principal findings</h4>Experiments employing Latin square design were conducted with a set of six huts to investigate the effects of the following on overnight mosquito trap catches: (1) placement of traps indoors or immediately outdoors, CO(2) supply, and presence of a human subject in the hut; (2) trap height for collecting mosquitoes immediately outdoors; (3) height and distance from hut; (4) interaction between multiple traps around a single hut and entry of mosquitoes into huts. A total of 106,600 adult mosquitoes (9.1% Anopheles gambiae s.l., 4.0% other Anopheles species) were collected over 42 nights. The high numbers of An. gambiae s.l. and other mosquitoes collected by odor-baited traps required CO(2) but were largely independent of the presence of a person sleeping in the hut or of trap placement indoors or outdoors. For outdoor collection that is considered less intrusive, traps opening 15 cm above the floor of the hut veranda were more highly effective than traps at other heights or further from the hut. There was no significant evidence of saturation or competition by the traps, with multiple traps around a hut each collecting almost as many mosquitoes as single traps and no effect on the numbers of mosquitoes entering the huts.<h4>Conclusions/significance</h4>The outdoor trapping protocol is convenient to compare attractiveness of different odors or synthetic chemicals to malaria vectors and other wild mosquitoes. The finding that such traps are reliably attractive in the presence or absence of a human volunteer encourages their potential development as standardised surveillance tools.
Project description:There is an urgent need for new insecticides for indoor residual spraying (IRS) which can provide improved and prolonged control of malaria vectors that have developed resistance to existing insecticides. The neonicotinoid, clothianidin represents a class of chemistry new to public health. Clothianidin acts as an agonist on nicotinic acetyl choline receptors. IRS with a mixture of Clothianidin and another WHO approved insecticide such as deltamethrin could provide improved control of insecticide resistant malaria vector populations and serve as a tool for insecticide resistance management.The efficacy and residual activity of a novel IRS mixture of deltamethrin and clothianidin was evaluated against wild pyrethroid resistant An. gambiae sl in experimental huts in Cove, Benin. Two application rates of the mixture were tested and comparison was made with clothianidin and deltamethrin applied alone. To assess the residual efficacy of the treatments on different local wall substrates, the inner walls of the experimental huts were covered with either cement, mud or plywood.Clothianidin demonstrated a clear delayed expression in mortality of wild pyrethroid resistant An. gambiae sl in the experimental huts which reached its full effect 120 hours after exposure. Overall mortality over the 12-month hut trial was 15% in the control hut and 24-29% in the deltamethrin-treated huts. The mixture of clothianidin 200mg/m2 and deltamethrin 25mg/m2 induced high overall hut mortality rates (87% on mud walls, 82% on cement walls and 61% on wooden walls) largely due to the clothianidin component and high hut exiting rates (67-76%) mostly due to the deltamethrin component. Mortality rates remained >80% for 8-9 months on mud and cement walls. The residual activity trend was confirmed by results from monthly in situ cone bioassays with laboratory susceptible An. gambiae Kisumu strain.IRS campaigns with the mixture of clothianidin plus deltamethrin have the potential to provide prolonged control of malaria transmitted by pyrethroid resistant mosquito populations.
Project description:Subsistence rice farmers in south-eastern Tanzania are often migratory, spending weeks or months tending to crops in distant fields along the river valleys and living in improvised structures known as Shamba huts, not fully protected from mosquitoes. These farmers also experience poor access to organized preventive and curative services due to long distances. Mosquito biting exposure in these rice fields, relative to main village residences was assessed, then a portable mosquito-proof hut was developed and tested for protecting these migratory farmers.Pair-wise mosquito surveys were conducted in four villages in Ulanga district, south-eastern Tanzania in 20 randomly-selected Shamba huts located in the distant rice fields and in 20 matched houses within the main villages, to assess biting densities and Plasmodium infection rates. A portable mosquito-proof hut was designed and tested in semi-field and field settings against Shamba hut replicas, and actual Shamba huts. Also, semi-structured interviews were conducted, timed-participant observations, and focus-group discussions to assess experiences and behaviours of the farmers regarding mosquito-bites and the mosquito-proof huts.There were equal numbers of mosquitoes in Shamba huts and main houses [RR (95% CI) 27 (25.1-31.2), and RR (95% CI) 30 (27.5-33.4)], respectively (P > 0.05). Huts having >1 occupant had more mosquitoes than those with just one occupant, regardless of site [RR (95% CI) 1.57 (1.30-1.9), P < 0.05]. Open eaves [RR (95% CI) 1.15 (1.08-1.23), P < 0.05] and absence of window shutters [RR (95% CI) 2.10 (1.91-2.31), P < 0.05] increased catches of malaria vectors. All Anopheles mosquitoes caught were negative for Plasmodium. Common night-time outdoor activities in the fields included cooking, eating, fetching water or firewood, washing dishes, bathing, and storytelling, mostly between 6 and 11 p.m., when mosquitoes were also biting most. The prototype hut provided 100% protection in semi-field and field settings, while blood-fed mosquitoes were recaptured in Shamba huts, even when occupants used permethrin-impregnated bed nets.Though equal numbers of mosquitoes were caught between main houses and normal Shamba huts, the higher proportions of blood-fed mosquitoes, reduced access to organized healthcare and reduced effectiveness of LLINs, may increase vulnerability of the itinerant farmers. The portable mosquito-proof hut offered sufficient protection against disease-transmitting mosquitoes. Such huts could be improved to expand protection for migratory farmers and possibly other disenfranchised communities.
Project description:Three expedition huts in the Ross Sea region of Antarctica, built between 1901 and 1911 by Robert F. Scott and Ernest Shackleton, sheltered and stored the supplies for up to 48 men for 3 years during their explorations and scientific investigation in the South Pole region. The huts, built with wood taken to Antarctica by the early explorers, have deteriorated over the past decades. Although Antarctica has one of the coldest and driest environments on earth, microbes have colonized the wood and limited decay has occurred. Some wood in contact with the ground contained distinct microscopic cavities within secondary cell walls caused by soft rot fungi. Cadophora spp. could be cultured from decayed wood and other woods sampled from the huts and artifacts and were commonly associated with the soft rot attack. By using internal transcribed spacer sequences of ribosomal DNA and morphological characteristics, several species of Cadophora were identified, including C. malorum, C. luteo-olivacea, and C. fastigiata. Several previously undescribed Cadophora spp. also were found. At the Cape Evans and Cape Royds huts, Cadophora spp. commonly were isolated from wood in contact with the ground but were not always associated with soft rot decay. Pure cultures of Cadophora used in laboratory decay studies caused dark staining of all woods tested and extensive soft rot in Betula and Populus wood. The presence of Cadophora species, but only limited decay, suggests there is no immediate threat to the structural integrity of the huts. These fungi, however, are widely found in wood from the historic huts and have the capacity to cause extensive soft rot if conditions that are more conducive to decay become common.
Project description:BACKGROUND:The development of resistance in vectors is one of the major impediments for malaria control. Adding synergists to insecticides has proven to be an alternative choice for controlling resistant mosquitoes. DawaPlus 3.0 and DawaPlus 4.0 are new long-lasting insecticidal nets (LLINs) in which deltamethrin and a synergist, piperonyl butoxide (PBO) are added into filaments and their efficacy was tested against resistant malaria vector, Anopheles culicifacies in experimental huts in India. METHODS:The performance of two trial nets in terms of deterrence induced exiting, blood-feeding inhibition and mortality of An. culicifacies was compared with DawaPlus 2.0 and untreated net. RESULTS:There was a significant reduction in entry, blood feeding and mortality (p?<?0.05) and increase in exit rates of An. culicifacies in the treatment arms compared to untreated arm. But, both candidate LNs washed 20 times could not perform better than the washed reference net (DawaPlus 2.0). Cone bioassay results showed that all the treatment arms (both washed and unwashed) produced?<?80% mortality of An. culicifacies before and after hut evaluation. CONCLUSIONS:DawaPlus 3.0 and DawaPlus 4.0 with their current specification may not be as effective as required to control the resistant vector, An. culicifacies, in east-central India.