bluuebunny/crossref_metadata_2025 huggingface dataset:
The evolution of bat nucleic acid‐sensing Toll‐like receptors
Authors: Escalera‐Zamudio Marina , Zepeda‐Mendoza M. Lisandra , Loza‐Rubio Elizabeth , Rojas‐Anaya Edith , Méndez‐Ojeda Maria L. , Arias Carlos F. , Greenwood Alex D.
Published: October 2015

We characterized the nucleic acid‐sensing Toll‐like receptors (TLR) of a New World bat species, the common vampire bat (Desmodus rotundus), and through a comparative molecular evolutionary approach searched for general adaptation patterns among the nucleic acid‐sensing TLRs of eight different bats species belonging to three families (Pteropodidae, Vespertilionidae and Phyllostomidae). We found that the bat TLRs are evolving slowly and mostly under purifying selection and that the divergence pattern of such receptors is overall congruent with the species tree, consistent with the evolution of many other mammalian nuclear genes. However, the chiropteran TLRs exhibited unique mutations fixed in ligand‐binding sites, some of which involved nonconservative amino acid changes and/or targets of positive selection. Such changes could potentially modify protein function and ligand‐binding properties, as some changes were predicted to alter nucleic acid binding motifs in TLR 9. Moreover, evidence for episodic diversifying selection acting specifically upon the bat lineage and sublineages was detected. Thus, the long‐term adaptation of chiropterans to a wide variety of environments and ecological niches with different pathogen profiles is likely to have shaped the evolution of the bat TLRs in an order‐specific manner. The observed evolutionary patterns provide evidence for potential functional differences between bat and other mammalian TLRs in terms of resistance to specific pathogens or recognition of nucleic acids in general.
Divergence times and the evolution of morphological complexity in an early land plant lineage (Marchantiopsida) with a slow molecular rate
Authors: Villarreal A. Juan Carlos , Crandall‐Stotler Barbara J. , Hart Michelle L. , Long David G. , Forrest Laura L.
Published: October 2015

We present a complete generic‐level phylogeny of the complex thalloid liverworts, a lineage that includes the model system Marchantia polymorpha. The complex thalloids are remarkable for their slow rate of molecular evolution and for being the only extant plant lineage to differentiate gas exchange tissues in the gametophyte generation. We estimated the divergence times and analyzed the evolutionary trends of morphological traits, including air chambers, rhizoids and specialized reproductive structures.

A multilocus dataset was analyzed using maximum likelihood and Bayesian approaches. Relative rates were estimated using local clocks.

Our phylogeny cements the early branching in complex thalloids. Marchantia is supported in one of the earliest divergent lineages. The rate of evolution in organellar loci is slower than for other liverwort lineages, except for two annual lineages. Most genera diverged in the Cretaceous. Marchantia polymorpha diversified in the Late Miocene, giving a minimum age estimate for the evolution of its sex chromosomes. The complex thalloid ancestor, excluding Blasiales, is reconstructed as a plant with a carpocephalum, with filament‐less air chambers opening via compound pores, and without pegged rhizoids.

Our comprehensive study of the group provides a temporal framework for the analysis of the evolution of critical traits essential for plants during land colonization.
Extension of oil biosynthesis during the mid‐phase of seed development enhances oil content in Arabidopsis seeds
Authors: Kanai Masatake , Mano Shoji , Kondo Maki , Hayashi Makoto , Nishimura Mikio
Published: October 2015

Regulation of oil biosynthesis in plant seeds has been extensively studied, and biotechnological approaches have been designed to increase seed oil content. Oil and protein synthesis is negatively correlated in seeds, but the mechanisms controlling interactions between these two pathways are unknown. Here, we identify the molecular mechanism controlling oil and protein content in seeds. We utilized transgenic Arabidopsis thaliana plants overexpressing WRINKLED1 (WRI1), a master transcription factor regulating seed oil biosynthesis, and knockout mutants of major seed storage proteins. Oil and protein biosynthesis in wild‐type plants was sequentially activated during early and late seed development, respectively. The negative correlation between oil and protein contents in seeds arises from competition between the pathways. Extension of WRI1 expression during mid‐phase of seed development significantly enhanced seed oil content. This study demonstrates that temporal activation of genes involved in oil or storage protein biosynthesis determines the oil/protein ratio in Arabidopsis seeds. These results provide novel insights into potential breeding strategies to generate crops with high oil contents in seeds.
Metabolic engineering for the production of plant isoquinoline alkaloids
Authors: Diamond Andrew , Desgagné‐Penix Isabel
Published: October 2015

Several plant isoquinoline alkaloids (PIAs) possess powerful pharmaceutical and biotechnological properties. Thus, PIA metabolism and its fascinating molecules, including morphine, colchicine and galanthamine, have attracted the attention of both the industry and researchers involved in plant science, biochemistry, chemical bioengineering and medicine. Currently, access and availability of high‐value PIAs [commercialized (e.g. galanthamine) or not (e.g. narciclasine)] is limited by low concentration in nature, lack of cultivation or geographic access, seasonal production and risk of overharvesting wild plant species. Nevertheless, most commercial PIAs are still extracted from plant sources. Efforts to improve the production of PIA have largely been impaired by the lack of knowledge on PIA metabolism. With the development and integration of next‐generation sequencing technologies, high‐throughput proteomics and metabolomics analyses and bioinformatics, systems biology was used to unravel metabolic pathways allowing the use of metabolic engineering and synthetic biology approaches to increase production of valuable PIAs. Metabolic engineering provides opportunity to overcome issues related to restricted availability, diversification and productivity of plant alkaloids. Engineered plant, plant cells and microbial cell cultures can act as biofactories by offering their metabolic machinery for the purpose of optimizing the conditions and increasing the productivity of a specific alkaloid. In this article, is presented an update on the production of PIA in engineered plant, plant cell cultures and heterologous micro‐organisms.
Integration of Cyanine, Merocyanine and Styryl Dye Motifs with Synthetic Bacteriochlorins
Authors: Yang Eunkyung , Zhang Nuonuo , Krayer Michael , Taniguchi Masahiko , Diers James R. , Kirmaier Christine , Lindsey Jonathan S. , Bocian David F. , Holten Dewey
Published: October 2015

Understanding the effects of substituents on spectral properties is essential for the rational design of tailored bacteriochlorins for light‐harvesting and other applications. Toward this goal, three new bacteriochlorins containing previously unexplored conjugating substituents have been prepared and characterized. The conjugating substituents include two positively charged species, 2‐(N‐ethyl 2‐quinolinium)vinyl‐ (B‐1) and 2‐(N‐ethyl 4‐pyridinium)vinyl‐ (B‐2), and a neutral group, acroleinyl‐ (B‐3); the charged species resemble cyanine (or styryl) dye motifs whereas the neutral unit resembles a merocyanine dye motif. The three bacteriochlorins are examined by static and time‐resolved absorption and emission spectroscopy and density functional theoretical calculations. B‐1 and B‐2 have Qy absorption bathochromically shifted well into the NIR region (822 and 852 nm), farther than B‐3 (793 nm) and other 3,13‐disubstituted bacteriochlorins studied previously. B‐1 and B‐2 have broad Qy absorption and fluorescence features with large peak separation (Stokes shift), low fluorescence yields, and shortened S1 (Qy) excited‐state lifetimes (~700 ps and ~100 ps). More typical spectra and S1 lifetime (~2.3 ns) are found for B‐3. The combined photophysical and molecular‐orbital characteristics suggest the altered spectra and enhanced nonradiative S1 decay of B‐1 and B‐2 derive from excited‐state configurations in which electron density is shifted between the macrocycle and the substituents.
Extensible Grids: Uniform Sampling on a Space Filling Curve
Authors: He Zhijian , Owen Art B.
Published: October 2015

We study the properties of points in [0,1]d generated by applying Hilbert's space filling curve to uniformly distributed points in [0, 1]. For deterministic sampling we obtain a discrepancy of O(n−1/d) for d⩾2. For random stratified sampling, and scrambled van der Corput points, we derive a mean-squared error of O(n−1−2/d) for integration of Lipschitz continuous integrands, when d⩾3. These rates are the same as those obtained by sampling on d-dimensional grids and they show a deterioration with increasing d. The rate for Lipschitz functions is, however, the best possible at that level of smoothness and is better than plain independent and identically distributed sampling. Unlike grids, space filling curve sampling provides points at any desired sample size, and the van der Corput version is extensible in n. We also introduce a class of piecewise Lipschitz functions whose discontinuities are in rectifiable sets described via Minkowski content. Although these functions may have infinite variation in the sense of Hardy and Krause, they can be integrated with a mean-squared error of O(n−1−1/d). It was previously known only that the rate was o(n−1). Other space filling curves, such as those due to Sierpinski and Peano, also attain these rates, whereas upper bounds for the Lebesgue curve are somewhat worse, as if the dimension were log2(3) times as high.
Double One-sided Cross-validation of Local Linear Hazards
Authors: Gámiz María Luz , Mammen Enno , Miranda María Dolores Martínez , Nielsen Jens Perch
Published: October 2015

The paper brings together the theory and practice of local linear kernel hazard estimation. Bandwidth selection is fully analysed, including double one-sided cross-validation that is shown to have good practical and theoretical properties. Insight is provided into the choice of the weighting function in the local linear minimization and it is pointed out that classical weighting sometimes lacks stability. A new semiparametric hazard estimator transforming the survival data before smoothing is introduced and shown to have good practical properties.
Bayesian Group Sequential Clinical Trial Design Using Total Toxicity Burden and Progression-Free Survival
Authors: Hobbs Brian P. , Thall Peter F. , Lin Steven H.
Published: October 2015

Delivering radiation to eradicate a solid tumour while minimizing damage to nearby critical organs remains a challenge. For oesophageal cancer, radiation therapy may damage the heart or lungs, and several qualitatively different, possibly recurrent toxicities that are associated with chemoradiation or surgery may occur, each at two or more possible grades. We describe a Bayesian group sequential clinical trial design, based on total toxicity burden (TTB) and the duration of progression-free survival, for comparing two radiation therapy modalities for oesophageal cancer. Each patient’s toxicities are modelled as a multivariate doubly stochastic Poisson point process, with marks identifying toxicity grades. Each grade of each type of toxicity is assigned a severity weight, elicited from clinical oncologists who are familiar with the disease and treatments. TTB is defined as a severity-weighted sum over the different toxicities that may occur up to 12 months from the start of treatment. Latent frailties are used to formulate a multivariate model for all outcomes. Group sequential decision rules are based on posterior mean TTB and progression-free survival time. The design proposed is shown to provide both larger power and smaller mean sample size when compared with a conventional bivariate group sequential design.
A General Angular Regression Model for the Analysis of Data on Animal Movement in Ecology
Authors: Rivest Louis-Paul , Duchesne Thierry , Nicosia Aurélien , Fortin Daniel
Published: October 2015

The paper investigates angular regressions that express the angles of an animal’s motion in terms of time varying directions and distances to environmental features that could influence its displacement. The mean direction proposed is a compromise between several possible targets. Conditions for the identifiability of the regression parameters are provided. Maximum likelihood estimators for the parameters are derived under two von Mises error structures. Robust sandwich estimators of the parameter variance–covariance matrix are obtained. The statistical methodology proposed is first used to reanalyse a classical data set on periwinkle movement. A second application investigates how bison trails are shaped by meadows and canopy gaps in Saskatchewan’s Prince Albert National Park.
Dividend Taxes and Income Shifting
Authors: Alstadsæter Annette , Jacob Martin
Published: October 2015

In this paper, we analyze whether a dividend tax cut for owner‐managers of closely held corporations encourages income shifting, income generation, or both. We use rich Swedish administrative micro data from 2000 to 2011 comprising detailed firm‐ and individual‐level information. We find robust evidence of extensive income shifting across tax bases in response to the 2006 Swedish dividend tax cut. Owner‐managers of closely held corporations reclassify earned income as dividend income but do not increase total income. The response is more pronounced for owner‐managers with tax incentives and with easier access to income shifting through a high ownership share.
Public Provision of Private Goods, Self‐Selection, and Income Tax Avoidance
Authors: Blomquist Sören , Christiansen Vidar , Micheletto Luca
Published: October 2015

Redistributive taxation should benefit those with low earnings capacity rather than those who choose a lower income to obtain tax savings. Several contributions have highlighted how public provision of work complements can discourage people from lowering labor supply to diminish taxable income. We show how tax avoidance, previously neglected, can alter the conclusions regarding public provision. Tax avoidance breaks the link between labor supply and reported income. An agent reducing his reported income to escape taxes might no longer forego a publicly provided labor complement, because he can now lower his income by avoiding more rather than working less.
Post‐Malthusian Dynamics in Pre‐Industrial Scandinavia
Authors: Klemp Marc , Møller Niels Framroze
Published: October 2015

Theories of economic growth hypothesize that the transition from pre‐industrial stagnation to sustained growth is associated with a post‐Malthusian phase in which technological progress raises income and spurs population growth while offsetting diminishing returns to labor. Evidence suggests that England was characterized by post‐Malthusian dynamics preceding the Industrial Revolution. However, given England's special position as the forerunner of the Industrial Revolution, it is unclear if a transitory post‐Malthusian period is a general phenomenon. Using data from Denmark, Norway, and Sweden, this research provides evidence for the existence of a post‐Malthusian phase in the transition from stagnation to growth in Scandinavia.
Optimal Redistribution with Endogenous Social Norms
Authors: Boadway Robin W. , Martineau Nicolas‐Guillaume
Published: October 2015

In this paper, we examine the effect of social norms on redistributive policies, where social norms are reflected in the degree of work participation among the different skill classes. Participation is driven both by the material incentives and heterogeneous preferences for leisure of each skill class, and by an endogenous social norm. Results for optimal redistributive taxation show that when the social norm enters as a benefit or cost for participants, participation taxes are generally lower than in its absence. Multiple participation equilibria can occur, and an engineered shift from a low‐ to a high‐participation equilibrium can be Pareto‐improving in the long run.
Measuring regional and district variations in the incidence of pregnancy‐induced hypertension in Ghana: challenges, opportunities and implications for maternal and newborn health policy and programmes
Authors: Antwi Edward , Klipstein‐Grobusch Kerstin , Quansah Asare Gloria , Koram Kwadwo A. , Grobbee Diederick , Agyepong Irene A.
Published: October 2015

Objectives

The objectives were to assess the quality of health management information system (HMIS) data needed for assessment of local area variation in pregnancy‐induced hypertension (PIH) incidence and to describe district and regional variations in PIH incidence.

Methods

A retrospective review of antenatal and delivery records of 2682 pregnant women in 10 district hospitals in the Greater Accra and Upper West regions of Ghana was conducted in 2013. Quality of HMIS data was assessed by completeness of reporting. The incidence of PIH was estimated for each district.

Results

Key variables for routine assessment of PIH such as blood pressure (BP) at antenatal visits, weight and height were 95–100% complete. Fundal height, gestational age and BP at delivery were not consistently reported. The incidence of PIH differed significantly between Greater Accra region (6.1%) and Upper West region (3.2%). Prevalence of obesity among pregnant women in Greater Accra region (13.9%) was significantly higher than that of women in Upper West region (2.2%).

Conclusions

More attention needs to be given to understanding local area variations in PIH and possible relationships with urbanisation and lifestyle changes that promote obesity, to inform maternal and newborn health policy. This can be done with good quality routine HMIS data.
Microbiological effectiveness of household water treatment technologies under field use conditions in rural Tanzania
Authors: Mohamed Hussein , Clasen Thomas , Njee Robert Mussa , Malebo Hamisi M. , Mbuligwe Stephen , Brown Joe
Published: October 2015

Objectives

To assess the microbiological effectiveness of several household water treatment and safe storage (HWTS) options in situ in Tanzania, before consideration for national scale‐up of HWTS.

Methods

Participating households received supplies and instructions for practicing six HWTS methods on a rotating 5‐week basis. We analysed 1202 paired samples (source and treated) of drinking water from 390 households, across all technologies. Samples were analysed for thermotolerant (TTC) coliforms, an indicator of faecal contamination, to measure effectiveness of treatment in situ.

Results

All HWTS methods improved microbial water quality, with reductions in TTC of 99.3% for boiling, 99.4% for Waterguard™ brand sodium hypochlorite solution, 99.5% for a ceramic pot filter, 99.5% for Aquatab® sodium dichloroisocyanurate (NaDCC) tablets, 99.6% for P&G Purifier of Water™ flocculent/disinfectant sachets, and 99.7% for a ceramic siphon filter. Microbiological performance was relatively high compared with other field studies and differences in microbial reductions between technologies were not statistically significant.

Conclusions

Given that microbiological performance across technologies was comparable, decisions regarding scale‐up should be based on other factors, including uptake in the target population and correct, consistent, and sustained use over time.
Structurally divergent lysophosphatidic acid acyltransferases with high selectivity for saturated medium chain fatty acids from Cuphea seeds
Authors: Kim Hae Jin , Silva Jillian E. , Iskandarov Umidjon , Andersson Mariette , Cahoon Rebecca E. , Mockaitis Keithanne , Cahoon Edgar B.
Published: October 2015

Lysophosphatidic acid acyltransferase (LPAT) catalyzes acylation of the sn‐2 position on lysophosphatidic acid by an acyl CoA substrate to produce the phosphatidic acid precursor of polar glycerolipids and triacylglycerols (TAGs). In the case of TAGs, this reaction is typically catalyzed by an LPAT2 from microsomal LPAT class A that has high specificity for C18 fatty acids containing Δ9 unsaturation. Because of this specificity, the occurrence of saturated fatty acids in the TAG sn‐2 position is infrequent in seed oils. To identify LPATs with variant substrate specificities, deep transcriptomic mining was performed on seeds of two Cuphea species producing TAGs that are highly enriched in saturated C8 and C10 fatty acids. From these analyses, cDNAs for seven previously unreported LPATs were identified, including cDNAs from Cuphea viscosissima (CvLPAT2) and Cuphea avigera var. pulcherrima (CpuLPAT2a) encoding microsomal, seed‐specific class A LPAT2s and a cDNA from C. avigera var. pulcherrima (CpuLPATB) encoding a microsomal, seed‐specific LPAT from the bacterial‐type class B. The activities of these enzymes were characterized in Camelina sativa by seed‐specific co‐expression with cDNAs for various Cuphea FatB acyl–acyl carrier protein thioesterases (FatB) that produce a variety of saturated medium‐chain fatty acids. CvLPAT2 and CpuLPAT2a expression resulted in accumulation of 10:0 fatty acids in the Camelina sativa TAG sn‐2 position, indicating a 10:0 CoA specificity that has not been previously described for plant LPATs. CpuLPATB expression generated TAGs with 14:0 at the sn‐2 position, but not 10:0. Identification of these LPATs provides tools for understanding the structural basis of LPAT substrate specificity and for generating altered oil functionalities.
Diterpenoid phytoalexin factor, a bHLH transcription factor, plays a central role in the biosynthesis of diterpenoid phytoalexins in rice
Authors: Yamamura Chihiro , Mizutani Emi , Okada Kazunori , Nakagawa Hitoshi , Fukushima Setsuko , Tanaka Atsunori , Maeda Satoru , Kamakura Takashi , Yamane Hisakazu , Takatsuji Hiroshi , Mori Masaki
Published: October 2015

Rice (Oryza sativa) produces diterpenoid phytoalexins (DPs), momilactones and phytocassanes as major phytoalexins. Accumulation of DPs is induced in rice by blast fungus infection, copper chloride or UV light. Here, we describe a rice transcription factor named diterpenoid phytoalexin factor (DPF), which is a basic helix‐loop‐helix (bHLH) transcription factor. The gene encoding DPF is expressed mainly in roots and panicles, and is inducible in leaves by blast infection, copper chloride or UV. Expression of all DP biosynthetic genes and accumulation of momilactones and phytocassanes were remarkably increased and decreased in DPF over‐expressing and DPF knockdown rice, respectively. These results clearly demonstrated that DPF positively regulates DP accumulation via transcriptional regulation of DP biosynthetic genes, and plays a central role in the biosynthesis of DPs in rice. Furthermore, DPF activated the promoters of COPALYL DIPHOSPHATE SYNTHASE2 (CPS2) and CYTOCHROME P450 MONOOXYGENASE 99A2 (CYP99A2), whose products are implicated in the biosynthesis of phytocassanes and momilactones, respectively. Mutations in the N‐boxes in the CPS2 upstream region, to which several animal bHLH transcription factors bind, decreased CPS2 transcription, indicating that DPF positively regulates CPS2 transcription through the N‐boxes. In addition, DPF partly regulates CYP99A2 through the N‐box. This study demonstrates that DPF acts as a master transcription factor in DP biosynthesis.
Blood transfusion in acute and chronic pediatric settings: beliefs and practices
Authors: Fortin Sylvie , Cardona Liliana Gomez , Latreille Martin , Tucci Marisa , Lacroix Jacques
Published: October 2015

BACKGROUND

Blood has been imbued with powerful connotations through history and across cultures. Currently bestowed with scientific meaning, blood nevertheless carries symbolic resonance. This study examines these representations among practitioners and sheds light on the clinical and nonclinical factors that guide blood transfusion (BT) decision‐making in Quebec, Canada.

STUDY DESIGN AND METHODS

With a qualitative exploratory study design, data were collected in the pediatric intensive care unit and the hematology‐oncology unit of Sainte‐Justine Hospital in 2009. A total of fifteen 1‐hour‐long semistructured interviews were conducted with physicians.

RESULTS

Physicians affirm that the symbolic connotations of blood found in the lay population do not influence their transfusion decisions. However, there are other “social” and “cultural’ aspects that influence these practices. Also, BT strategies remain diverse across units. Practitioners perceive these situations as resulting from insufficient training and by the existence of an “oral tradition” and a professional culture that are resistant to change.

CONCLUSION

BT practices differ within and across units. Many dimensions intervene in the decision to transfuse, from individual clinical appreciation and local unit “culture” to formal and ad hoc training. Consistent change in BT can only occur with the implementation of norms and guidelines that are endorsed by key influential figures. An extensive multicentered study is necessary to better understand how social and cultural factors affect BT practices. This knowledge will sustain an enlightened clinical practice and lead to the recognition that peer practices are also embedded in professional cultures.
Preliminary evaluation of a highly automated instrument for the selection of CD34+ cells from mobilized peripheral blood stem cell concentrates
Authors: Stroncek David F. , Tran Minh , Frodigh Sue Ellen , David‐Ocampo Virginia , Ren Jiaqiang , Larochelle Andre , Sheikh Virginia , Sereti Irini , Miller Jeffery L. , Longin Kevin , Sabatino Marianna
Published: October 2015

BACKGROUND

Cell selection is an important part of manufacturing cellular therapies. A new highly automated instrument, the CliniMACS Prodigy (Miltenyi Biotec), was evaluated for the selection of CD34+ cells from mobilized peripheral blood stem cell (PBSC) concentrates using monoclonal antibodies conjugated to paramagnetic particles.

STUDY DESIGN AND METHODS

PBSCs were collected by apheresis from 36 healthy subjects given granulocyte–colony‐stimulating factor (G‐CSF) or G‐CSF plus plerixafor. CD34+ cells from 11 PBSC concentrates were isolated with the automated CliniMACS Prodigy and 25 with the semiautomated CliniMACS Plus Instrument.

RESULTS

The proportion of CD34+ cells in the selected products obtained with the two instruments was similar: 93.6 ± 2.6% for the automated and 95.7 ± 3.3% for the semiautomated instrument (p > 0.05). The recovery of CD34+ cells from PBSC concentrates was less for the automated than the semiautomated instrument (51.4 ± 8.2% vs. 65.1 ± 15.7%; p = 0.019). The selected products from both instruments contained few and similar quantities of platelets (PLTs) and red blood cells. The depletion of CD3+ cells was less with the automated instrument (4.34 ± 0.2 log depletion vs. 5.20 ± 0.35 log depletion; p < 1 × 10−6). Removal of PLTs from PBSC concentrates by washing was associated with better CD34+ cell recovery. We explored the reasons for lower CD34+ cell recovery by the Prodigy and found that the nonselected cells for the Prodigy contained more PLTs than those for the CliniMACS Plus.

CONCLUSIONS

CD34+ cells can be effectively selected from mobilized PBSC concentrates with the CliniMAC Prodigy, but the recovery of CD34+ cells and depletion of CD3+ cells was lower than with the semiautomated CliniMACS Plus Instrument.
A Conversation with David MacDougall: Reflections on the Childhood and Modernity Workshop Films
Authors: Potts Rowena
Published: October 2015

This interview with ethnographic filmmaker and theorist David MacDougall focuses on his most recent collaborative research project: an ongoing, five‐year enterprise entitled Childhood and Modernity: Indian Children's Perspectives. In the project, which emerged from his earlier work documenting the social worlds and experiences of children in diverse institutions across India, MacDougall directs a series of workshops that equip small cohorts of boys and girls between the ages of 10 and 13 with basic video skills. These young, first‐time filmmakers produce short films based on their investigation of research topics they select and design themselves. The process recognizes and amplifies the perspectives of children at a time of transformation and change in India. In a conversation with filmmaker Rowena Potts, a doctoral student in cultural anthropology at New York University and facilitator of a Childhood and Modernity workshop in Kolkata, MacDougall describes the evolution and contours of this project and its implications for ethnographic film, visual anthropology, and global studies of childhood.
Attitudes towards Englishes in India
Authors: BERNAISCH TOBIAS , KOCH CHRISTOPHER
Published: October 2015

With the help of a survey building on 13 bipolar pairs arranged on a six‐point semantic differential scale, the present paper studies Indian English speakers’ attitudes towards their local variety Indian English contrastively by simultaneously examining their attitudes towards American English, British English and Sri Lankan English. The results show that although Indian speakers of English display a positive attitude towards Indian English, which is most pronounced with the group of young female informants possibly leading an ongoing linguistic change in India, the informants view British English in a more favourable light. In addition, Indian English speakers show the least positive attitude towards Sri Lankan English, which may be an indication of mutual attitudinal demarcation between the two neighbour varieties.
Shaft-Less Energy Storage Flywheel
Authors: Li Xiaojun , Palazzolo Alan , Tingey Dustin , Han Xu , McMullen Patrick , Wang Zhiyang
Published: October 2015

This paper provides an overview of a 100 kw flywheel capable of 100 kW-Hr energy storage that is being built by Vibration Control and Electromechanical Lab (VCEL) at Texas A&M University and Calnetix Technologies. The novel design has a potential of nearly doubling the energy density of conventional steel flywheels. Applications include renewable energy source energy storage, frequency regulation at power plants, regenerative braking on vehicles and cranes and backup power at data centers and hospitals. The design and construction of this Department of Energy sponsored flywheel will be presented.
Optimum Heating Pattern of a Ground Source Heat Reference Map
Authors: Funabiki Ayako , Yabuki Taisei , Oguma Masahito
Published: October 2015

A ground source heat reference map (GSHRM) shows the minimum necessary thermal performance of the ground heat exchanger (GHE) of a ground source heat pump (GSHP) system. Thermal performance depends on thermal properties of the ground, the ground temperature profile, heat advection by groundwater flow, and the GHE operating pattern. This study modeled optimum heating and cooling modes for a GSHRM. First, continuous and intermittent operation modes were compared, and a standard operation time was defined. In a standard household GSHP system, the quantity of heat transferred from the ground depends on household energy demand, which is relatively constant. Once the demand is known, an operation mode is selected that can meet it. Continuous operation increased the total amount of heat exchanged over a period of time but lowered the heat flux at the GHE, whereas intermittent operation with relatively long stopped periods decreased the total amount of heat but did not greatly decrease the heat flux at the GHE. Second, energy-saving efficiency and cost factors were compared among intermittent operation modes. Operation costs consist of the electrical energy supplied to the heat and circulation pumps. At a given operation time, the energy supplied to the heat pump depends on its coefficient of performance (COP), whereas that supplied to the circulation pump depends on its pressure loss, hence on the GHE length. A long GHE has a higher initial cost. Thus, the optimum heating pattern must consider the configuration of the GSHP system, including energy-saving efficiency and cost factors.
Design and Commissioning of an Experimental Set-Up to Evaluate the Performance of a Solar Absorption Chiller With Thermal Storage
Authors: Baldwin Christopher , Cruickshank Cynthia A. , Bowie Daniel
Published: October 2015

As the demand for cooling increases in Canada, it creates a greater energy demand on the utility grid by placing peak loads during the summer months. As a result, air conditioning in the residential sector is responsible for a disproportionately large and increasing amount of CO2 emissions in Canada. One potential solution is the use of solar thermally driven absorption chillers, however before their widespread use in Canada is possible, extensive testing and optimization of the systems must be conducted to determine their feasibility in the Canadian climate. This paper discusses a full scale experimental test rig that has been recently constructed and commissioned to experimentally evaluate the performance of a commercially available solar absorption chiller with integrated thermal storage. The complete system is described, including the system’s test capabilities, the instrumentation installed, the control system developed, and the calibration and uncertainty analysis completed on each individual sensor and the system as a whole. Additionally, the paper examines the charge cycle of the solar absorption chiller being studied, and compares the results to simulation results obtained from a TRNSYS model of the test apparatus.
Simplified Modeling of Thermal Storage Tank for Distributed Energy Heat Recovery Applications
Authors: Rahman Aowabin , Fumo Nelson , Smith Amanda D.
Published: October 2015

A simplified mathematical model was developed to analyze a storage tank containing a stationary fluid with hot and cold heat exchanger coils. The model is to be used as a screening tool for determining tank size and configurations for operation with a given power generation unit in a combined cooling, heating and power (CCHP) system. As such, the model was formulated so that it requires minimal information about the thermo-physical properties of the fluids and design parameters in order to determine the temperature profiles of the stored fluid and the heat transfer fluid for turbulent flow inside the heat exchangers. The presented model is implemented computationally with varying number of nodes, before comparing it with a more detailed model that take into account the variation of thermo-physical properties, as well as the effects of thermal de-stratification and heat loss to the ambient. The simplified model provided accurate temperature predictions that could subsequently be used to design a stratified tank system for a given CCHP application.
A Study on Various Aerodynamic Effects of Pointed Tip Blade
Authors: Roy Shrabanti , Lee Kyoungsoo , Huque Ziaul , Kommalapati Raghava
Published: October 2015

A wind turbine blade performance depends on various parameters of which the shape of the blade is one of the most important one. In this work the shape of the tip of original NREL Phase-VI blade (S809 airfoil) has been modified to determine the changes in the blade aerodynamic performance. The chord length of new blade is kept similar to the original NREL blade up to 90% of the span. Last 10% was modified to a pointed tip at the pitch axis. This paper presents a comparative study of the effect of pointed tip on aerodynamic loads. CFD simulations were performed on both original NREL shape and pointed tip shape blades. The simulation results of pointed tip blade were compared with both experimental and simulation results of original blade. Ansys geometry modeler was used to draw the geometry and to generate the grids. Ansys CFX solver and post processor were used for simulation and calculation of the results. To predict the near wall transitional effect SST Gamma Theta turbulence model was used. Results of pressure coefficient along the chord at various blade sections of the pointed tip blade were found to be almost similar to the original NREL blade CFD results. Tangential and normal force along the span of pointed tip blade at different wind speeds showed some similarity in results compared with CFD results of original NREL blade. From the velocity contour the separation of flow with the increase of wind speed can clearly be observed. Thrust and torque effects are also observed at various wind speeds. The torque values for the pointed tip blade were found to be higher in the pre-stall and stall region but slightly lower in post-stall region. But compared to the torque values the difference in thrust at the same region is found to be negligible. Pointed tip thrust values are in better agreement at high wind speeds with respect to the experimental data. The flow separation at high wind speed is also found to be less with pointed tip blade compared to the original blade.
Thermoelectric Power Generation by Harvesting the Waste Heat From a Car Engine
Authors: Cha Jong K. , Lee Thomas Y. , Gan Yong X.
Published: October 2015

Internal combustion (IC) engines typically have an efficiency of less than 35%. This is largely due to the fact that much of the energy dissipates into waste heat. However, the waste heat may be converted into electricity by using energy conversion modules made from bismuth telluride. In this work, it is demonstrated that electricity can be generated from waste heat due to the difference in temperatures. The thermal to electrical energy conversion is achieved by using a self-assembled thermoelectric generator (TEG). The TEG (thermoelectric generator) uses two different types of metallic compound semiconductors, known as n-typed and p-typed, to create voltage when the junctions are held at different temperatures. The work mechanism is based on the Seebeck effect. In this study, the TEGs are made from bismuth telluride (Bi-Te) with relatively high energy conversion efficiencies. In addition, it is readily available. The installation location of the TEG is studied. For testing purposes and convenience, the top of the radiator of a 1990 Mazda Miata car was chosen. The TEG and an aluminum finned heat sink were placed in order on the top of the radiator. Thermal paste was applied to both surfaces and secured with zip ties. A vent was cut on the hood of the car to promote airflow between the fins. Appropriate electrical wiring allowed the unit to output to a digital multi-meter which was located within the car for operator to take data. It is found from the measured results that 0.948 V is the maximum output and the average voltage is 0.751 V. The highest voltage came from driving mountain paths due to the heat sink and coolant temperature being higher than nominal. We estimate that placing an insulator between the heat sink and TEG would push the maximum voltage over 1.0 V. During the cool down phase, the TEG produced electricity continuously with a maximum voltage of 0.9 V right after engine cutoff. The voltage decreased to about 0.6 V within 40 minutes. It is found that the relationship between the temperature difference and output voltage is linear.
Toward Efficient Residential Buildings in Hot and Humid Climates
Authors: Al Qubaisi Ayesha , Al Alili Ali
Published: October 2015

The design, construction, and operation of highly efficient residential buildings in hot and humid climates represent a unique challenge for architects, contractors, and building owners. In this paper, a case study on the performance of a residential building located in hot and humid location is presented. The building is a single-family house, which is modeled as a multi-zone building. The transient systems simulation program (TRNSYS) is used to simulate the building under Abu Dhabi’s typical meteorological year conditions. The results are presented in terms of the annual energy consumption and the indoor thermal comfort. The Predicted Mean Vote (PMV) is used to model the thermal comfort. In addition, the results of applying local building codes, Estidama, and international building codes, ASHRAE 90.2 and LEED, on the building’s performance are compared. The results will help in finding the effectiveness of these building standards in reducing the energy consumption of residential building in hot and humid regions.
Parametric and Thermal Management Optimization of a Steel Slag Based Packed Bed Heat Storage
Authors: Ortega-Fernández Iñigo , Gil Antoni , Faik Abdessamad , Rodríguez-Aseguinolaza Javier , D’Aguanno Bruno
Published: October 2015

In this work steel slag, one of the main by-products of the steelmaking industry, is proposed as a competitive and effective heat storage material. The implemented storage design suggested for this material is a solid packed bed arrangement based in the temperature stratification (thermocline) phenomena. In particular, two different solutions based on different storage tank geometries, cylindrical and conical, have been modeled by using computational fluid dynamic (CFD) methods. In addition, both geometries have been simulated under two different operation modes as a function of the used heat transfer fluid: solar salt and air. This selection permitted to investigate the operation of the proposed storage for current CSP technologies which make use of molten salt as storage/heat transfer fluid and also the analysis of the system when the operation parameters are potentially associated to new generation CSP plants at higher temperatures, above 600 °C. The comparison between the simulated systems has allowed to determine the influence of the driving parameters on the proposed storage solution, such as the operation temperature range, nature of the heat transfer fluid or geometrical implications. The thermal management of the storage unit has also been shown during a transient operation up to a reproducible behavior.

Overall, the selected parameters for the presented modeling analysis have revealed the high potential of steel slag as heat storage material and the suitability and flexibility of the implemented packed bed solution.
Novel Tubular Receiver Panel Configurations for Increased Efficiency of High-Temperature Solar Receivers
Authors: Christian Joshua M. , Ortega Jesus D. , Ho Clifford K.
Published: October 2015

Typical Concentrated Solar Power (CSP) central receiver power plants require the use of either an external or cavity receiver. Previous and current external receivers consist of a series of tubes connected to manifolds that form a cylindrical or rectangular shape such as in the cases of Solar One, Solar Two, and most recently the Ivanpah solar plant. These receivers operate at high surface temperatures (>600°C) at which point thermal re-radiation is significant. However, the geometric arrangement of these heat transfer tubes results in heat losses directly to the environment. This work focused on how to fundamentally reduce this heat loss through the manipulation of heat transfer tube configurations. Four receiver configurations are studied: flat receiver (base case study), a radial receiver with finned structures (fins arranged in a circular pattern on a cylinder), a louvered finned structure (horizontal and angled fins on a flat plate), and a vertical finned structure (fins oriented vertically along a flat plate). The thermal efficiency, convective heat loss patterns, and air flow around each receiver design is found using the computational fluid dynamics (CFD) code ANSYS FLUENT. Results presented in this paper show that alternative tubular configurations increase thermal efficiency by increasing the effective solar absorptance of these high-temperature receivers by increasing the light trapping effects of the receiver, reducing thermal emittance to the environment, and reducing the overall size of the receiver. Each receiver configuration has finned structures that take advantage of the directional dependence of the heliostat field resulting in a light trapping effect on the receiver. The finned configurations tend to lead to “hot” regions on the receiver, but the new configurations can take advantage of high local view factors (each surface can “see” another receiver surface) in these regions through the use of heat transfer fluid (HTF) flow patterns. The HTF reduces the temperatures in these regions increasing the efficiency of heat transfer to the fluid. Finally, the new receiver configurations have a lower overall optical intercept region resulting in a higher geometric concentration ratio for the receiver. Compared to the base case analysis (flat plate receiver), the novel tubular geometries results showed an increase in thermal efficiency.
Structural Analysis of a Direct Heated Tubular Solar Receiver for Supercritical CO2 Brayton Cycle
Authors: Ortega Jesus D. , Christian Joshua M. , Ho Clifford K.
Published: October 2015

Closed-loop super-critical carbon dioxide (sCO2) Brayton cycles are being evaluated in combination with concentrating solar power to provide higher thermal-to-electric conversion efficiencies relative to conventional steam Rankine cycles. However, high temperatures (650–700°C) and pressures (20–25 MPa) are required in the solar receiver. In this study, an extensive material review was performed along with a tube size optimization following the ASME Boiler and Pressure Vessel Code and B31.1 and B313.3 codes respectively. Subsequently, a thermal-structural model was developed using ANSYS Fluent and Structural to design and analyze the tubular receiver that could provide the heat input for a ∼2 MWth plant. The receiver will be required to provide an outlet temperature of 650°C (at 25 MPa) or 700°C (at 20 MPa). The induced thermal stresses were applied using a temperature gradient throughout the tube while a constant pressure load was applied on the inner wall. The resulting stresses have been validated analytically using constant surface temperatures. The cyclic loading analysis was performed using the Larson-Miller creep model in nCode Design Life to define the structural integrity of the receiver over the desired lifetime of ∼10,000 cycles. The results have shown that the stresses induced by the thermal and pressure load can be withstood by the tubes selected. The creep-fatigue analysis displayed the damage accumulation due to the cycling and the permanent deformation of the tubes. Nonetheless, they are able to support the required lifetime. As a result, a complete model to verify the structural integrity and thermal performance of a high temperature and pressure receiver has been developed. This work will serve as reference for future design and evaluation of future direct and indirect tubular receivers.
Assessment of Photovoltaic Surface Texturing on Transmittance Effects and Glint/Glare Impacts
Authors: Yellowhair Julius , Ho Clifford K.
Published: October 2015

Standard glass and polymer covers on photovoltaic modules can partially reflect the sunlight causing glint and glare. Glint and glare from large photovoltaic installations can be significant and have the potential to create hazards for motorists, air-traffic controllers and pilots flying near installations. In this work, the reflectance, surface roughness and reflected solar beam spread were measured from various photovoltaic modules acquired from seven different manufacturers. The surface texturing of the PV modules varied from smooth to roughly textured. Correlations between the measured surface texturing (roughness parameters) and beam spread (subtended angle) were determined. These correlations were then used to assess surface texturing effects on transmittance and ocular impacts of glare from photovoltaic module covers. The results can be used to drive the designs for photovoltaic surface texturing to improve transmittance and minimize glint/glare.