Estimating stellar rotation from starspot detection during planetary transits

A new method for determining the stellar rotation period is proposed here, based on the detection of starspots during transits of an extra-solar planet orbiting its host star. As the planet eclipses the star, it may pass in front of a starspot which will then make itself known through small flux variations in the transit light curve. If we are lucky enough to catch the same spot on two consecutive transits, it is possible to estimate the stellar rotational period. This method is successfully tested on transit simulations on the Sun yielding the correct value for the solar period. By detecting two starspots on more than one transit of HD 209458 observed by the Hubble Space Telescope, it was possible to estimate a period of either 9.9 or 11.4 days for the star, depending on which spot is responsible for the signature in the light curve a few transits later. Comparison with period estimates of HD209458 reported in the literature indicates that 11.4 days is the most likely stellar rotation period.Comment: 13 pages, 5 figure

Private message me s'il vous plait : Preferences for personal and masspersonal communications on Facebook among American and French students

Facebook, a social networking tool used worldwide, provides affordances for public/masspersonal and private/personal communication. Based on previous cross-cultural research demonstrating that masspersonal communication is adaptive in individualistic cultural contexts, we hypothesized that using Facebook to broadcast messages to one's entire network would be relatively more common and appealing to people in countries with greater individualistic values. To test this hypothesis, data were collected in two Western countries differing in levels of individualism, France (204 women, 47 men) and the U.S. (75 women, 89 men), through questionnaires measuring their Facebook use. Results indicated that American college students had larger Facebook networks and used both more masspersonal and personal communication with acquaintances compared to French college students. Masspersonal communication was mediated by network size. French students used more personal communication with friends than American students, but this association was not mediated by network size. These findings suggest that the appeal of masspersonal communication increases as a function of social network size, however, level of engagement in personal communication on Facebook is a function of other cultural differences between the U.S. and France, such as differences in individualistic values

Workplan for Catalyzing Collaboration with Amazonian Universities in the Large Scale Biosphere-Atmosphere Experiment in Amazonia (LBA)

Success of the Large-Scale Biosphere-Atmospheric Experiment in Amazonia (LBA) program depends on several critical factors, the most important being the effective participation of Amazonian researchers and institutions. Without host-county counterparts, particularly in Amazonia, many important studies cannot he undertaken due either to lack of qualified persons or to legal constraints. No less important, the acceptance of the LBA program in Amazonia is also dependent on what LBA can do for improving the scientific expertise in Amazonia. Gaining the active investment of Amazonian scientists in a comprehensive research program is not a trivial task. Potential collaborators are few, particularly where much of the research was to be originally focused - the southern arc of Brazilian Amazonia. The mid-term goals of the LBA Committee on Training and Education are to increase the number of collaborators and to demonstrate that LBA will be of benefit to the region

Tempted to Text: College Students’ Mobile Phone Use During a Face-to-Face Interaction With a Close Friend

We examined whether emerging adults would engage in mobile phone use (MPU) when given the opportunity to socialize face-to-face with a close friend in a laboratory setting. Sixty-three U.S. college student friendship dyads rated their friendship quality in an online survey before coming into the laboratory together. When they arrived for their appointment, they were asked to wait together in a room for 5 min. A hidden camera recorded each dyad. Friends then separately rated the quality of the interaction. We coded time spent using mobile phone in seconds. A hierarchical regression conducted at the level of the dyad controlling for friendship quality and gender showed that more MPU was associated with lower quality interactions. We discuss findings in terms of the potential for MPU to interfere with the development of friendship intimacy

Topic Guide: Building reciprocal rural-urban linkages through infrastructure investment and development. Evidence on Demand, UK

This document is designed to be a practical and analytical guide for development practitioners working to promote socially just, environmentally sustainable and resilient rural and urban development in rapidly urbanising low- and middle-income countries. It focuses specifically on Asia and Africa as the world’s two most rapidly urbanising continents, and promotes the mutual benefits available for both urban and rural areas that can be gained by promoting their positive interdependencies and linkages. The Guide presents evidence from the literature and examples from practice where infrastructure has been used to build and harness reciprocal rural-urban linkages. It also shows how DFID has historically championed a nuanced perspective on the potential benefits of urbanisation beyond a narrow focus on built up urban areas. If revitalised, such perspective could have a significant impact on guiding future infrastructural interventions not only by DFID but also by other bilateral and multilateral development agencies. Section 1 introduces the Guide – what and who it is for, who wrote it and how it is structured. Section 2 seeks to provide development practitioners with an understanding of the current trends, challenges and opportunities in urbanisation, both globally and in Africa and Asia specifically. Sections 3-5 aim to provide development practitioners with the advice and evidence required to promote the positive interdependencies between urban and rural development - otherwise referred to as reciprocal rural-urban linkages. This is split into sections focusing on ways to maximise and manage economic and development potential (3), physical growth and the sustainability of the natural resource base (4) and social inclusion and equality (5). Section 6 presents a number of case studies to show how a range of types of infrastructure, and the services they support, can help build reciprocal rural-urban linkages in practice. Section 7 concludes by discussing the centrality of local governance in infrastructure provision and service delivery, viewed through the lens of water and sanitation. This peer reviewed Topic Guide has been produced by the Development Planning Unit at University College London (UCL) with the assistance of the UK Department for International Development (DFID) contracted through the Climate, Environment, Infrastructure and Livelihoods Professional Evidence and Applied Knowledge Services (CEIL PEAKS) programme, jointly managed by DAI (which incorporates HTSPE Limited) and IMC Worldwide Limited

Adolescents’ daily face-to-face and computer-mediated communication: Associations with autonomy and closeness to parents and friends

The amount of time adolescents spend communicating via digital technologies such as smartphones has led to concerns that computer-mediated communication (CMC) is displacing face-to-face (FtF) interactions and disrupting social development. Although many studies have examined CMC in adolescents' relationships with friends, few studies have examined the role of CMC in adolescents' renegotiation of closeness and autonomy with parents. To examine this issue, we administered an online daily diary with 169 U.S. adolescents to estimate the time they spend in CMC and FtF interactions and the number of texts they exchange with friends and parents. On the last day of the survey, we asked adolescents about their emotional closeness to friends and parents and their balance of closeness and volition with parents. Overall, we found more evidence for social stimulation than displacement effects of CMC. Texts and CMC time with friends predicted friend closeness after accounting for FtF time with friends; texts with parents predicted parent closeness after accounting for FtF time with parents. We also found support for our hypothesis that CMC would be associated with greater adolescent volition. CMC time with parents predicted greater volitional dependence (volition plus closeness) whereas texts with friends predicted greater independent decision-making (volition plus distance). We discuss how communication technologies are integrated into U.S. adolescents' relationships with friends and parents and how CMC can facilitate, rather than stifle, adolescents' adjustment of autonomy-relatedness with parents and their construction of emotional closeness with friends

Contributions to the study of blood constituents in domestic animals in South Africa. 3. Normal values for the activity of glyceraldehyde-phosphate dehydrogenase and glucose-6-phosphate dehydrogenase in the erythrocytes of sheep

Normal values have been established for the activity of glyceraldehyde-phosphate dehydrogenase and glucose-6-phosphate dehydrogenase in the erythrocytes of sheep maintained under experimental and field conditions in South Africa. The 10 per cent lower, 80 per cent and 10 per cent upper limits have been established for the former enzyme as 400- 424, 425-730 and 731-900 micrograms/ml of blood respectively. Negligible activity of the latter enzyme has been demonstrated in the ovine erythrocyte by three different methods. Glycolysis in the red blood cells of the sheep is believed to proceed mainly via the direct Embden-Meyerhof pathway. The importance of these findings with regard to the ovine disease syndromes, geeldikkop and enzootic icterus, is mentioned.The journals have been scanned in colour with a HP 5590 scanner; 600 dpi. Adobe Acrobat v.11 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

1,25-(OH)2D receptors are decreased in parathyroid glands from chronically uremic dogs

1,25-(OH)2D receptors are decreased in parathyroid glands from chronically uremic dogs. 1,25-(OH)2D has been shown to suppress the synthesis and secretion of parathyroid hormone in vivo and in dispersed parathyroid cell cultures. Control of transcription by 1,25-(OH)2D is believed to be mediated by interaction of this hormone with a specific receptor within target cells. We have examined the 1,25-(OH)2D receptor in parathyroid glands from normal dogs and chronic renal failure dogs. The levels of receptor were fourfold lower in parathyroid extracts from these uremic dogs than in those from normal dogs (109 ± 11 vs. 446 ± 61 fmol/mg protein). No differences were observed in the binding affinity for 1,25-(OH)2D or in the sedimentation in sucrose density gradients. Since this receptor has been shown to be upregulated by 1,25-(OH)2D, our findings of lower levels of receptor could be attribed to decreased serum concentrations of 1,25-(OH)2D in chronically uremic animals. Regression analysis of log serum 1,25-(OH)2D versus log receptor content yielded a correlation coefficient of 0.62 with P < 0.02. Decreased receptor content showed a negative correlation with serum N-terminal PTH (r= 0.71 and P < 0.01). It is likely that this reduced 1,25-(OH)2D receptor number in the parathyroid glands of chronically uremic animals renders the glands less responsive to the inhibitory action of 1,25-(OH)2D on the synthesis and secretion of PTH, and may contribute to the hyperparathyroidism associated with chronic renal failure