Competence of a Spray Passive Down-draft Evaporative Cooling (PDEC) System for Space Cooling

A spray PDEC system has been relatively less considered than other passive cooling strategies as one of the viable low-energy solutions in the cooling of buildings while having a great potential in energy savings. This study is intended to evaluate the capability of a spray PDEC system for space cooling. It comprises four simulation scenarios to see the system response and influence of indoor thermal environment when a spray PDEC system is adopted as a primary cooling system in two different climates. The simulation results show that a spray PDEC system causes a substantial variation in the indoor thermal environment and sensible cooling rates while substantiating significant energy savings

Significance of Parameters Affecting the Performance of a Passive Down-Draft Evaporative Cooling (PDEC) Tower with a Spray System

PDEC towers with spray systems are known to achieve substantial energy savings. Various parameters such as the wet-bulb depression, the tower height, and the wind speed have been known to be key factors affecting the performance of the system. To date, the significance of these parameters and other important factors have not been adequately treated in the literature. There also has been a lack of models that can successfully investigate potential benefits of the system under various conditions where this particular system could be applicable. To address these critical issues, this study performed a parametric analysis by using a FLUENT model validated against experimental data. It demonstrated the significance of individual parameters including water droplet sizes. As a result, practical design guidelines for important system parameters were presented. A statistical analysis was then used to formulate analytic models that account for all of the relationships found in this study between the parameters and the supply air conditions of the system. Two regression equations were formulated for predicting supply air temperature and velocity

Analysis of the system response of a spray passive downdraft evaporative cooling system

A spray Passive Downdraft Evaporative Cooling (PDEC) system achieves great savings for space cooling and improves indoor environmental quality by supplying a large amount of fresh outdoor air. As previous studies heavily focused on the energy saving capability of a spray PDEC system due to lack of methods for a detailed analysis, the influence of cool humid supply air from a spray PDEC system in a space in buildings has not been comprehensively studied. This study is intended to evaluate the competence of a spray PDEC system as a primary cooling system in typical spaces in a primary school building by developing a method using building energy simulation tool. It runs one-day simulations in a hot dry climate and a warm moderate climate in order to distinctly examine the benefits and the areas that should be advanced. It analyses how a spray PDEC system responds to the space cooling loads and spaces conditioned by the system thermally behave. The results of the simulations affirm that a spray PDEC system is capable of conditioning building spaces in the two climates, indicating some areas to be improved

Performance Control of a Spray Passive Down-Draft Evaporative Cooling System

A spray passive down-draft evaporative cooling system has been regarded as a low-energy cooling system that leads significant energy savings in the cooling of buildings. While the energy saving capability of the system has been proven, the ability to control a comfortable indoor environment is still inadequate due to strong climatic dependency. This study seeks viable solutions to advance the control competence of the system by mitigating critical problems of the system to be a reliable cooling application in the cooling of buildings. It proposes potential control strategies for the system and alternative operations. It develops a control algorithm for the proposed control strategies and implements the algorithm in EnergyPlus. A simulation analysis follows to examine the functionality of each proposed control strategy and alternative operations. The results of the simulations ascertain that a spray PDEC system with a water flow control performs better. In addition, a spray PDEC system contributes most when it operates as a secondary cooling system to abate space cooling loads and to maintain a steady thermal environment by reducing 62.1% electricity for space cooling and 47.9% water consumption in a warm-moderate climate

Regression models for linking patterns of growth to a later outcome:Infant growth and childhood overweight

Abstract Background Regression models are widely used to link serial measures of anthropometric size or changes in size to a later outcome. Different parameterisations of these models enable one to target different questions about the effect of growth, however, their interpretation can be challenging. Our objective was to formulate and classify several sets of parameterisations by their underlying growth pattern contrast, and to discuss their utility using an expository example. Methods We describe and classify five sets of model parameterisations in accordance with their underlying growth pattern contrast (conditional growth; being bigger v being smaller; becoming bigger and staying bigger; growing faster v being bigger; becoming and staying bigger versus being bigger). The contrasts are estimated by including different sets of repeated measures of size and changes in size in a regression model. We illustrate these models in the setting of linking infant growth (measured on 6 occasions: birth, 6 weeks, 3, 6, 12 and 24 months) in weight-for-height-for-age z-scores to later childhood overweight at 8y using complete cases from the Norwegian Childhood Growth study (n = 900). Results In our expository example, conditional growth during all periods, becoming bigger in any interval and staying bigger through infancy, and being bigger from birth were all associated with higher odds of later overweight. The highest odds of later overweight occurred for individuals who experienced high conditional growth or became bigger in the 3 to 6 month period and stayed bigger, and those who were bigger from birth to 24 months. Comparisons between periods and between growth patterns require large sample sizes and need to consider how to scale associations to make comparisons fair; with respect to the latter, we show one approach. Conclusion Studies interested in detrimental growth patterns may gain extra insight from reporting several sets of growth pattern contrasts, and hence an approach that incorporates several sets of model parameterisations. Co-efficients from these models require careful interpretation, taking account of the other variables that are conditioned on

Putting the self in self-correction: findings from the loss-of-confidence project

Science is often perceived to be a self-correcting enterprise. In principle, the assessment of scientific claims is supposed to proceed in a cumulative fashion, with the reigning theories of the day progressively approximating truth more accurately over time. In practice, however, cumulative self-correction tends to proceed less efficiently than one might naively suppose. Far from evaluating new evidence dispassionately and infallibly, individual scientists often cling stubbornly to prior findings. Here we explore the dynamics of scientific self-correction at an individual rather than collective level. In 13 written statements, researchers from diverse branches of psychology share why and how they have lost confidence in one of their own published findings. We qualitatively characterize these disclosures and explore their implications. A cross-disciplinary survey suggests that such loss-of-confidence sentiments are surprisingly common among members of the broader scientific population yet rarely become part of the public record. We argue that removing barriers to self-correction at the individual level is imperative if the scientific community as a whole is to achieve the ideal of efficient self-correction

Applying refinement to the use of mice and rats in rheumatoid arthritis research

Rheumatoid arthritis (RA) is a painful, chronic disorder and there is currently an unmet need for effective therapies that will benefit a wide range of patients. The research and development process for therapies and treatments currently involves in vivo studies, which have the potential to cause discomfort, pain or distress. This Working Group report focuses on identifying causes of suffering within commonly used mouse and rat ‘models’ of RA, describing practical refinements to help reduce suffering and improve welfare without compromising the scientific objectives. The report also discusses other, relevant topics including identifying and minimising sources of variation within in vivo RA studies, the potential to provide pain relief including analgesia, welfare assessment, humane endpoints, reporting standards and the potential to replace animals in RA research

Regional and cellular gene expression changes in human Huntington's disease brain

Huntington's disease (HD) pathology is well understood at a histological level but a comprehensive molecular analysis of the effect of the disease in the human brain has not previously been available. To elucidate the molecular phenotype of HD on a genome-wide scale, we compared mRNA profiles from 44 human HD brains with those from 36 unaffected controls using microarray analysis. Four brain regions were analyzed: caudate nucleus, cerebellum, prefrontal association cortex [Brodmann's area 9 (BA9)] and motor cortex [Brodmann's area 4 (BA4)]. The greatest number and magnitude of differentially expressed mRNAs were detected in the caudate nucleus, followed by motor cortex, then cerebellum. Thus, the molecular phenotype of HD generally parallels established neuropathology. Surprisingly, no mRNA changes were detected in prefrontal association cortex, thereby revealing subtleties of pathology not previously disclosed by histological methods. To establish that the observed changes were not simply the result of cell loss, we examined mRNA levels in laser-capture microdissected neurons from Grade 1 HD caudate compared to control. These analyses confirmed changes in expression seen in tissue homogenates; we thus conclude that mRNA changes are not attributable to cell loss alone. These data from bona fide HD brains comprise an important reference for hypotheses related to HD and other neurodegenerative disease

Gene content evolution in the arthropods

Arthropods comprise the largest and most diverse phylum on Earth and play vital roles in nearly every ecosystem. Their diversity stems in part from variations on a conserved body plan, resulting from and recorded in adaptive changes in the genome. Dissection of the genomic record of sequence change enables broad questions regarding genome evolution to be addressed, even across hyper-diverse taxa within arthropods. Using 76 whole genome sequences representing 21 orders spanning more than 500 million years of arthropod evolution, we document changes in gene and protein domain content and provide temporal and phylogenetic context for interpreting these innovations. We identify many novel gene families that arose early in the evolution of arthropods and during the diversification of insects into modern orders. We reveal unexpected variation in patterns of DNA methylation across arthropods and examples of gene family and protein domain evolution coincident with the appearance of notable phenotypic and physiological adaptations such as flight, metamorphosis, sociality, and chemoperception. These analyses demonstrate how large-scale comparative genomics can provide broad new insights into the genotype to phenotype map and generate testable hypotheses about the evolution of animal diversity

The clonal evolution of metastatic colorectal cancer

Tumor heterogeneity and evolution drive treatment resistance in metastatic colorectal cancer (mCRC). Patient-derived xenografts (PDXs) can model mCRC biology; however, their ability to accurately mimic human tumor heterogeneity is unclear. Current genomic studies in mCRC have limited scope and lack matched PDXs. Therefore, the landscape of tumor heterogeneity and its impact on the evolution of metastasis and PDXs remain undefined. We performed whole-genome, deep exome, and targeted validation sequencing of multiple primary regions, matched distant metastases, and PDXs from 11 patients with mCRC. We observed intricate clonal heterogeneity and evolution affecting metastasis dissemination and PDX clonal selection. Metastasis formation followed both monoclonal and polyclonal seeding models. In four cases, metastasis-seeding clones were not identified in any primary region, consistent with a metastasis-seeding-metastasis model. PDXs underrepresented the subclonal heterogeneity of parental tumors. These suggest that single sample tumor sequencing and current PDX models may be insufficient to guide precision medicine