Identifying Genes Influencing the Efficiency of Photosynthesis

Photosynthesis adapts to environmental conditions over time.¹ Varying environmental conditions lead to stress accumulation on the plant.² A genetic library has been assembled for forward genetic screening of Arabidopsis thaliana.³ Arabidopsis Thaliana is a model plant used as a model organism in growth experiments. This research project aims to identify and analyze candidate genes that impact the efficiency of photosynthesis. These genes can be transplanted into commercial crops to increase efficiency of photosynthesis and crop yields

Insights into C4 metabolism from comparative deep sequencing.

C4 photosynthesis suppresses the oxygenation activity of Ribulose Bisphosphate Carboxylase Oxygenase and so limits photorespiration. Although highly complex, it is estimated to have evolved in 66 plant lineages, with the vast majority lacking sequenced genomes. Transcriptomics has recently initiated assessments of the degree to which transcript abundance differs between C3 and C4 leaves, identified novel components of C4 metabolism, and also led to mathematical models explaining the repeated evolution of this complex phenotype. Evidence is accumulating that this complex and convergent phenotype is partly underpinned by parallel evolution of structural genes, but also regulatory elements in both cis and trans. Furthermore, it appears that initial events associated with acquisition of C4 traits likely represent evolutionary exaptations related to non-photosynthetic processes.We thank the BBSRC for grant BB/1002243/1 and the EU 3to4 program for financial support.This is the accepted manuscript. The final version is available at http://www.sciencedirect.com/science/article/pii/S1369526615000680

Atom chips on direct bonded copper substrates

We present the use of direct bonded copper (DBC) for the straightforward fabrication of high power atom chips. Atom chips using DBC have several benefits: excellent copper/substrate adhesion, high purity, thick (> 100 microns) copper layers, high substrate thermal conductivity, high aspect ratio wires, the potential for rapid (< 8 hr) fabrication, and three dimensional atom chip structures. Two mask options for DBC atom chip fabrication are presented, as well as two methods for etching wire patterns into the copper layer. The wire aspect ratio that optimizes the magnetic field gradient as a function of power dissipation is determined to be 0.84:1 (height:width). The optimal wire thickness as a function of magnetic trapping height is also determined. A test chip, able to support 100 A of current for 2 s without failing, is used to determine the thermal impedance of the DBC. An assembly using two DBC atom chips to provide magnetic confinement is also shown.Comment: 8 pages, 5 figure

Evaluation of denoising strategies to address motion-correlated artifacts in resting-state functional magnetic resonance imaging data from the human connectome roject

Like all resting-state functional connectivity data, the data from the Human Connectome Project (HCP) are adversely affected by structured noise artifacts arising from head motion and physiological processes. Functional connectivity estimates (Pearson's correlation coefficients) were inflated for high-motion time points and for high-motion participants. This inflation occurred across the brain, suggesting the presence of globally distributed artifacts. The degree of inflation was further increased for connections between nearby regions compared with distant regions, suggesting the presence of distance-dependent spatially specific artifacts. We evaluated several denoising methods: censoring high-motion time points, motion regression, the FMRIB independent component analysis-based X-noiseifier (FIX), and mean grayordinate time series regression (MGTR; as a proxy for global signal regression). The results suggest that FIX denoising reduced both types of artifacts, but left substantial global artifacts behind. MGTR significantly reduced global artifacts, but left substantial spatially specific artifacts behind. Censoring high-motion time points resulted in a small reduction of distance-dependent and global artifacts, eliminating neither type. All denoising strategies left differences between high- and low-motion participants, but only MGTR substantially reduced those differences. Ultimately, functional connectivity estimates from HCP data showed spatially specific and globally distributed artifacts, and the most effective approach to address both types of motion-correlated artifacts was a combination of FIX and MGTR

Consumer Behavior Research in Emerging Consumer Markets: The Case of the Optimum Stimulation Level in South Africa

More than two-thirds of the world's consumers live in emerging consumer markets and transitional economies (ECMs). A fuller understanding of consumer behavior and further advancement of consumer research as an academic discipline require that the validity of theories and models of consumer behavior developed in the Western cultural context be examined in ECMs as well. In this paper, we examine the measurement invariance and nomological relations involving OSL in one of Africa's most important ECMs - South Africa. Our research setting presents an especially stringent context for testing consumer behavior theories. Many respondents are challenged severely economically and educationally, many have probably never had a job and some are illiterate. Nevertheless, the results provide evidence on the cross-cultural generalizability of OSL and exploratory consumer behavior theory. We found a high degree of stability in the OSL structure across these four major ethnic groups in South Africa. Meaningful and theoretically predictable nomological relations are obtained with values, sociodemographics, and exploratory consumer behavior. Suggestions for future research on OSL and for consumer behavior research in general in ECMs are discussed.http://deepblue.lib.umich.edu/bitstream/2027.42/39636/3/wp251.pd

Value Priorities and Consumer Behavior in a Transitional Economy: The Case of South Africa

We examine consumer value priorities in Africa's most important transitional economy, viz., The Republic of South Africa. To the best of our knowledge, this is the first extensive study of value priorities with a large, representative sample of consumers in a transitional economy. We study the structure of the value priorities, their antecedents, and their relations with optimum stimulation level, lifestyle interests, brand purchase behavior, and consumption of innovative products. A number of hypotheses concerning the effects of various value domains are developed, using Schwartz's (1992, 1994) value theory. Value priorities are measured with a new measurement instrument, the Portraits Questionnaire (Schwartz, Lehmann, and Roccas 1997). This instrument is specifically developed for use in generally less educated populations often found in less-advanced transitional economies. We find strong evidence on the validity of the structure of value priorities in South Africa and on the relation of the value priorities with other constructs. The results emphasize the importance of gender, age, and the ethnic cultural group or subculture to which the person belongs as antecedents of value priorities. Other relevant antecedents include household income, degree of urbanization, and being member of a religion or not. Systematic and predictable relations with optimum stimulation level are observed. Systematic effects of value priorities on lifestyle interests, brand switching behavior, and consumption of innovative financial products are also found. The results are generally consistent with our hypotheses. Little consumer research has been conducted in transitional economies, and even less with broad representative groups of consumers. That is unfortunate from a practical point of view as the economic importance of these countries is rapidly growing. Transitional economies are increasingly moving from a product(ion)-oriented focus to a market-oriented focus in which consumer desires become paramount. However, there is still a long way to go, one reason being that a consumer orientation is new to most transitional economies. In most transitional economies, the economic system was geared toward fulfilling the needs of the state and of a privileged minority of its population. The lack of knowledge and insight in consumer behavior in transitional economies is also unfortunate from an academic point of view. Transitional economies are undergoing rapid changes that are quite unique in history. This allows for a "natural experiment" in which the effects of radical changes in society on consumer behavior can be studied in a real world setting. Moreover, it is not at all clear that the concepts and theories developed for western countries are equally relevant and applicable to transitional economies. Cunningham and Green (1984, p. 9) argued that there is "a need for more fundamental research in international marketing in order to adapt established marketing concepts to the realities of the international marketing place." In similar vein, Monroe (1993) stated that: "In this age of globalization, we need to move beyond the relative security of our own backyards and investigate issues relative to consumption on an international basis." We attempt to contribute to recti@g this situation by studying value priorities of consumers in the most important African transitional economy, viz., the Republic of South Africa. South Africa entered this decade as the world's most isolated country; politically, economically, and socially. In the years since Mandela's election, the extensive web of international anti-Apartheid laws has been repealed and South Africa has become a full partner in the world economic and political system again. These external transitions hide the extent of internal change South Africa must undergo before the transition to a market-based economy can be said to be a true success. South Africa is essentially a two-tier society in that most Whites live and work in a modem economy while the majority of Black population often interact with that economy only superficially and experience a living standard comparable to the rest of Africa (United Nations 1996). These two worlds in which South Africans live are the legacy of an Apartheid state that effectively excluded 80% of the population from free economic and political participation. The ambitious reforms of the new South African government share a fundamental goal of using the full potential of South Africa's human capital to build a stable, free, and market-based economy. Economic reforms are beginning to spread ownership of companies more widely in an economy where 80% of Johannesburg Stock Exchange shares are owned by a handful of companies. Para-state companies in numerous industries are being privatized. There are clear parallels to the situation in Eastern Europe. In the former communist countries was also a clear distinction between the elite (i.e., Communist Party members) and the majority of the population. In Eastern Europe, economic and political freedom of the majority of the population was also severely restricted. Moreover, the concentration in South Africa of economic power in a few hands is in important respects similar to (pretransition) Eastern Europe. In this study, we will examine the value priorities of South African consumers, their antecedents, and their relevance for understanding key aspects of consumer behavior. Values underlie a large and important part of human cognition and behavior (Schwartz 1992). They transcend specific objects, in contrast to attitudes, which must be examined in relation to specific and carefully defined objects (Rokeach 1973). An examination of values provides both an overall picture of a central cognitive structure of the individual, as well as a means of linking central beliefs to specific attitudes. Values provide potentially powerful explanations of human behavior because they serve as standards of conduct, tend to be limited in number, universal across cultures, and temporally remarkably stable (Kamakura and Mazzon 1991, Rokeach 1973, Schwartz 1992). Consequently, it is not surprising that values have been found to be valuable in explaining a variety of attitudes and behaviors in the consumer context (see Burgess 1992, Homer and Kahle 1988, and Kamakura and Mazzon 1991 for overviews). In the following sections, we will first discuss the construct of personal values and its role in consumer behavior. Following a discussion of the research methodology, we present our empirical findings. We close with a discussion of the results, and provide suggestions for future research.http://deepblue.lib.umich.edu/bitstream/2027.42/39554/3/wp166.pd

Shared characteristics underpinning C 4 leaf maturation derived from analysis of multiple C 3 and C 4 species of Flaveria

Most terrestrial plants use C3 photosynthesis to fix carbon. In multiple plant lineages a modified system known as C4 photosynthesis has evolved. To better understand the molecular patterns associated with induction of C4 photosynthesis, the genus Flaveria that contains C3 and C4 species was used. A base to tip maturation gradient of leaf anatomy was defined, and RNA sequencing was undertaken along this gradient for two C3 and two C4Flaveria species. Key C4 traits including vein density, mesophyll and bundle sheath cross-sectional area, chloroplast ultrastructure, and abundance of transcripts encoding proteins of C4 photosynthesis were quantified. Candidate genes underlying each of these C4 characteristics were identified. Principal components analysis indicated that leaf maturation and the photosynthetic pathway were responsible for the greatest amount of variation in transcript abundance. Photosynthesis genes were over-represented for a prolonged period in the C4 species. Through comparison with publicly available data sets, we identify a small number of transcriptional regulators that have been up-regulated in diverse C4 species. The analysis identifies similar patterns of expression in independent C4 lineages and so indicates that the complex C4 pathway is associated with parallel as well as convergent evolution

Consumer Behavior Research in Emerging Consumer Markets: The Case of the Optimum Stimulation Level in South Africa

More than two-thirds of the world's consumers live in emerging consumer markets and transitional economies (ECMs). A fuller understanding of consumer behavior and further advancement of consumer research as an academic discipline require that the validity of theories and models of consumer behavior developed in the Western cultural context be examined in ECMs as well. In this paper, we examine the measurement invariance and nomological relations involving OSL in one of Africa's most important ECMs - South Africa. Our research setting presents an especially stringent context for testing consumer behavior theories. Many respondents are challenged severely economically and educationally, many have probably never had a job and some are illiterate. Nevertheless, the results provide evidence on the cross-cultural generalizability of OSL and exploratory consumer behavior theory. We found a high degree of stability in the OSL structure across these four major ethnic groups in South Africa. Meaningful and theoretically predictable nomological relations are obtained with values, sociodemographics, and exploratory consumer behavior. Suggestions for future research on OSL and for consumer behavior research in general in ECMs are discussed.

Genome-Wide Transcription Factor Binding in Leaves from C3 and C4 Grasses.

The majority of plants use C3 photosynthesis, but over 60 independent lineages of angiosperms have evolved the C4 pathway. In most C4 species, photosynthesis gene expression is compartmented between mesophyll and bundle-sheath cells. We performed DNaseI sequencing to identify genome-wide profiles of transcription factor binding in leaves of the C4 grasses Zea mays, Sorghum bicolor, and Setaria italica as well as C3 Brachypodium distachyon In C4 species, while bundle-sheath strands and whole leaves shared similarity in the broad regions of DNA accessible to transcription factors, the short sequences bound varied. Transcription factor binding was prevalent in gene bodies as well as promoters, and many of these sites could represent duons that influence gene regulation in addition to amino acid sequence. Although globally there was little correlation between any individual DNaseI footprint and cell-specific gene expression, within individual species transcription factor binding to the same motifs in multiple genes provided evidence for shared mechanisms governing C4 photosynthesis gene expression. Furthermore, interspecific comparisons identified a small number of highly conserved transcription factor binding sites associated with leaves from species that diverged around 60 million years ago. These data therefore provide insight into the architecture associated with C4 photosynthesis gene expression in particular and characteristics of transcription factor binding in cereal crops in general.BBSRC ERC CONACy

The Association Between Sedentary Behaviors During Weekdays and Weekend with Change in Body Composition in Young Adults

Background: High sedentary time has been considered an important chronic disease risk factor but there is only limited information on the association of specific sedentary behaviors on weekdays and weekend-days with body composition. The present study examines the prospective association of total sedentary time and specific sedentary behaviors during weekdays and the weekend with body composition in young adults. Methods: A total of 332 adults (50% male; 27.7 ±3.7 years) were followed over a period of 1 year. Time spent sedentary, excluding sleep (SED), and in physical activity (PA) during weekdays and weekend-days was objectively assessed every 3 months with a multisensor device over a period of at least 8 days. In addition, participants reported sitting time, TV time and non-work related time spent at the computer separately for weekdays and the weekend. Fat mass and fat free mass were assessed via dual x-ray absorptiometry and used to calculate percent body fat (%BF). Energy intake was estimated based on TDEE and change in body composition. Results: Cross-sectional analyses showed a significant correlation between SED and body composition (0.18 ≤ r ≤ 0.34). Associations between body weight and specific sedentary behaviors were less pronounced and significant during weekdays only (r ≤ 0.16). Nevertheless, decrease in SED during weekends, rather than during weekdays, was significantly associated with subsequent decrease in %BF (β = 0.06, p \u3c0.01). After adjusting for PA and energy intake, results for SED were no longer significant. Only the association between change in sitting time during weekends and subsequent %BF was independent from change in PA or energy intake (β%BF = 0.04, p = 0.01), while there was no significant association between TV or computer time and subsequent body composition. Conclusions: The stronger AIMS Public Health Volume 3, Issue 2, 375-388. prospective association between sedentary behavior during weekends with subsequent body composition emphasizes the importance of leisure time behavior in weight management