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The solar magnesium II core-to-wing ratio has been a well-studied proxy for chromospheric activity since 1978. Daily measurements at high spectral (0.1 nm) resolution began with the launch of the Solar Radiation and Climate Experiment (SORCE) in 2003. The next generation of measurements from the Extreme Ultraviolet Sensor (EUVS) on the Geostationary Operational Environmental Satellite 16 (GOES-16) will add high time cadence (every 30 seconds) to the observational Mg II irradiance record. We present a comparison of the two measurements during the period of overlap.
Ultraviolet (UV) Solar spectral Irradiance (SSI) has been measured from orbit on a regular basis since the beginning of the space age. These observations span four Solar Cycles, and they are crucial for our understanding of the Sun-Earth connection and space weather. SSI at these wavelengths are the main drivers for the upper atmosphere including the production and destruction of ozone in the stratosphere. The instruments that measure UV SSI not only require good preflight calibration, but also need a robust method to maintain that calibration on orbit. We will give an overview of the catalog of current and former UV SSI measurements along with the calibration philosophy of each instrument and an estimation of the uncertainties in the published irradiances.
In view of the considerable ground covered by the Commission at its Paris meetings and the fairly complete record of the activities of institutes and observatories, etc. published in the Minutes, it has not been deemed profitable by the president to call for further reports in advance of the Stockholm meeting. At the Paris meeting it was agreed that such reports be printed independently before each meeting of the Union and that reprints of or references to the published reports be sent to the president. It is hoped that all such reports if ready will be made available before the Stockholm meeting so that they may be summarized by the representatives in attendance or by the president and recorded in the Minutes. With reference to the pronouncement at the Paris meeting “that it is eminently desirable that more attention be given to the development of accurate general perturbations and mean elements on the basis of accurate osculating elements”, the president has visited the Planeten-Institut at Frankfurt and the Rechen-Institut at Berlin and has been in correspondence with the Leningrad Institute. From these sources particularly valuable material has been received.
From the combination of VLBI phase-referenced observations and Hipparcos satellite data, we have found evidence of a low-mass object orbiting the late-type star AB Doradus. The mass of the new object is near the hydrogen burning limit and will constitute a precise point for calibrating the low end of the main sequence. This represents the first detection of a low-mass stellar companion using the VLBI technique, which could become an important tool in future searches for planets and brown dwarfs orbiting other stars.
Scholarly interest has been growing in an episode of Old World globalisation of food resources significantly predating the ‘Silk Road’. This process was characteristic of crosscontinental translocations of starch-based crops mostly during the third and second millennia BC but which might have been initiated in an earlier period (Jones et al. 2011). Among these translocations we can include a range of crops originally from Southwest Asia, notably bread wheat and barley, and others originally from northern China, such as broomcorn and foxtail millet (Hunt et al. 2008; Motuzaite-Matuzeviciute et al. 2013). Parallel patterns of crop movement between North Africa and South Asia have been observed and discussed in some depth (Boivin & Fuller 2009; Fuller et al. 2011; Boivin et al. 2013). The impetus behind this growth of interest has been the expansion of archaeobotanical research in South and East Asia over the past decade (Fuller 2002; Crawford 2006; Lee et al. 2007; Liu et al. 2008; Zhao 2010). This paper considers the agents responsible for the food globalisation process during the third and second millennia BC. A key aspect of trans-Eurasian starch-crop movement was that it constituted an addition to agricultural systems, rather than movement to regions devoid of existing starch-based agriculture. Other economic plants, such as grapes, dates and peas, also moved considerable distances in the archaeological record, often to areas previously devoid of those plants. However, the novel starchy crops held a particular significance. In both cases, Southwest Asian wheat and barley and East Asian millets went on to become important staple foods in many of their new destinations.
The classic image of Upper Palaeolithic hunter-gatherers in Europe envisages them hunting large mammals in largely treeless landscapes. That is partly due to the nature of the surviving archaeological evidence, and the poor preservation of plant remains at such ancient sites. As this study illustrates, however, the potential of Upper Palaeolithic sites to yield macrofossil remains of plants gathered and processed by human groups has been underestimated. Large scale flotation of charred deposits from hearths such as that reported here at Dolní Vӗstonice II not only provides insight into the variety of flora that may have been locally available, but also suggests that some of it was being processed and consumed as food. The ability to exploit plant foods may have been a vital component in the successful colonisation of these cold European habitats.
The majority of the early crops grown in Europe had their origins in south-west Asia, and were part of a package of domestic plants and animals that were introduced by the first farmers. Broomcorn millet, however, offers a very different narrative, being domesticated first in China, but present in Eastern Europe apparently as early as the sixth millennium BC. Might this be evidence of long-distance contact between east and west, long before there is any other evidence for such connections? Or is the existing chronology faulty in some way? To resolve that question, 10 grains of broomcorn millet were directly dated by AMS, taking advantage of the increasing ability to date smaller and smaller samples. These showed that the millet grains were significantly younger than the contexts in which they had been found, and that the hypothesis of an early transmission of the crop from east to west could not be sustained. The importance of direct dating of crop remains such as these is underlined.
Francesco Guala has developed some novel and radical ideas on the problem of external validity, a topic that has not received much attention in the experimental economics literature. In this paper I argue that his views on external validity are not justified and the conclusions which he draws from these views, if widely adopted, could substantially undermine the experimental economics enterprise. In rejecting the justification of these views, the paper reaffirms the importance of experiments in economics.
We studied the thickness variation of equally doped ZnO:Al films used as conductive window layer in Cu(In,Ga)(Se,S)2 (CIGSSe) thin film solar cells. The IV-characteristics of solar cells with window layer thickness of d1=200nm exhibit a strong enhancement of the short-circuit current density JSC (ΔJSC = 3mA/cm2) as compared to samples with module-like ZnO:Al-film thickness (d2=1200nm). Accordingly, the quantum efficiency reveals the spectral regimes where the JSC-gain occurs. Moreover, current-voltage measurements reveal that the cells with thicker ZnO:Al exhibit slightly decreased open circuit voltage VOC. This finding can be assigned to a decreased net-doping density NA, which appears to be introduced by additional heat flux during the longer process time required for deposition of thicker ZnO:Al films. However, the improved efficiency of solar cells with thinner window layer comes along with an increase of the series resistance (RS) by almost a factor of 2, which will have consequences for the series connection of elements in a module. XRD-diffractograms and SEM cross-section imaging suggest that the enhanced RS in cells with thin ZnO:Al is not exclusively related to the thickness but is also due to a reduced (002)-texture and an elongated lateral charge carrier pathway.
One consequence of “high stakes testing” in Tuscaloosa area schools has been exclusion of materials science faculty from any meaningful participation in middle and high school classrooms. Beyond the loss of resources from the classroom that Materials Science faculty and their students represent, this also has negative consequences for faculty wanting to build ties to schools to address NSF’s “broader impact” criteria. A group of STEM and Education faculty at The University of Alabama have been testing a team based approach designed to overcome the systemic constraints that prevent effective STEM/K-12 collaboration. Teams consisting of a high school teacher, a STEM faculty member, and a STEM graduate student have spent three weeks during summer 2010 to identify/develop and implement an inquiry based science experiments. The experiments are being tested on science campers at McWane Science Center prior to being assessed in the teachers’ classrooms during the fall semester. The experiments were chosen by each team and represent significant advances over those currently available in the schools. By setting a problem that no team member is able to solve alone an environment was produced where success requires meaningful collaboration. Preliminary qualitative evaluation indicates deeper understanding of the school environment by the STEM faculty and greater respect for the skills teachers bring to this endeavor. Successes in this pilot program have generated credibility with the local school district, opening the door to scaling up the project, and developing further positive ties. Incorporation of lead teachers from Alabama Science in Motion also allows the experiments developed to be widely disseminated throughout Alabama, as well as providing a mechanism to identify existing experiments to enhance.
Structurally disordered refractory ternary films such as titanium silicon nitride (Ti-Si-N) have potential as advanced diffusion barriers in future ULSI metallization schemes. Here we present results on purely thermal metalorganic chemical vapor deposition (CVD) of Ti-Si-N. At temperatures between 300 and 450°C, tetrakis(diethylamido)titanium (TDEAT), silane, and ammonia react to grow Ti-Si-N films with Si contents of 0-20 at.%. Typical impurity contents are 5-10 at.%H and 0.5 to 1.5 at.% C, with no O or other impurities detected in the bulk of the film. Although the film resistivity increases with increasing Si content, it remains below 1000 μΩ-cm for films with less than 5 at.% Si. These films are promising candidates for advanced diffusion barriers.