69,118 research outputs found

    Remote Sensing of Giant Reed with QuickBird Satellite Imagery

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    QuickBird high resolution (2.8 m) satellite imagery was evaluated for distinguishing giant reed ( Arundo donax L.) infestations along the Rio Grande in southwest Texas. (PDF has 5 pages.

    Strong-coupling scales and the graph structure of multi-gravity theories

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    In this paper we consider how the strong-coupling scale, or perturbative cutoff, in a multi-gravity theory depends upon the presence and structure of interactions between the different fields. This can elegantly be rephrased in terms of the size and structure of the `theory graph' which depicts the interactions in a given theory. We show that the question can be answered in terms of the properties of various graph-theoretical matrices, affording an efficient way to estimate and place bounds on the strong-coupling scale of a given theory. In light of this we also consider the problem of relating a given theory graph to a discretised higher dimensional theory, a la dimensional deconstruction.Comment: 23 pages, 7 figures; v2: additional references included, and minor typos corrected; version published in JHE

    The decoupling limit of Multi-Gravity: Multi-Galileons, Dualities and More

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    In this paper we investigate the decoupling limit of a particular class of multi-gravity theories, i.e. of theories of interacting spin-2 fields. We explicitly compute the interactions of helicity-0 modes in this limit, showing that they take on the form of multi-Galileons and dual forms. In the process we extend the recently discovered Galileon dualities, deriving a set of new multi-Galileon dualities. These are also intrinsically connected to healthy, but higher-derivative, multi-scalar field theories akin to `beyond Horndeski' models.Comment: 41 pages, 2 figure

    Commentary: California Secessionists Channel Logic of Southern Slaveholders

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    \u27Thursday night the streets were filled with excited crowds. No one talks of anything but the necessity for prompt action. . . . It is hardly prudent for any man to express his opinion adverse to immediate secession, so heated are the public passions, so intolerant of restraint is the popular will. You would probably assume that this report came from California in the wake of the 2016 election, right? After all, Alex Padilla, the California secretary of state, has now authorized the Yes California Independence Campaign to begin collecting signatures for a state referendum on California\u27s secession from the United States. [excerpt

    In Defense of the Electoral College

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    There is hardly anything in the Constitution harder to explain, or easier to misunderstand, than the Electoral College. And when a presidential election hands the palm to a candidate who comes in second in the popular vote but first in the Electoral College tally, something deep in our democratic viscera balks and asks why the Electoral College shouldn’t be dumped as a useless relic of 18th century white, gentry privilege. Actually, there have been only five occasions when a closely divided popular vote and the electoral vote have failed to point in the same direction. No matter. After last week’s results, we’re hearing a litany of complaints: the Electoral College is undemocratic, the Electoral College is unnecessary, the Electoral College was invented to protect slavery — and the demand to push it down the memory hole. (excerpt

    Probing the environment of emerin by Enhanced ascorbate peroxidase 2 (APEX2)-mediated proximity labeling.

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    Emerin is one of the best characterized proteins of the inner nuclear membrane, but can also occur at the level of the endoplasmic reticulum. We now use enhanced ascorbate peroxidase 2 (APEX2) to probe the environment of emerin. APEX2 can be used as a genetic tag that produces short-lived yet highly reactive biotin species, allowing the modification of proteins that interact with or are in very close proximity to the tagged protein. Biotinylated proteins can be isolated using immobilized streptavidin and analyzed by mass spectrometry. As an alternative to the standard approach with a genetic fusion of APEX2 to emerin, we also used RAPIDS (rapamycin- and APEX-dependent identification of proteins by SILAC), a method with improved specificity, where the peroxidase interacts with the protein of interest (i.e., emerin) only upon addition of rapamycin to the cells. We compare these different approaches, which, together, identify well-known interaction partners of emerin like lamin A and the lamina associated polypeptide 1 (LAP1), as well as novel proximity partners

    School Climate Development Survey

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    Over the last twenty-five years the Consortium on Chicago School Research has engaged in systematic study of more than 400 Chicago Public Schools to determine organizational traits that are related to improvement in student learning. This effort was designed to help explain widely divergent levels of student success between very similar schools in the Chicago system. Initial discussions with educators at all levels, reviews of previous research, pilot studies, and field studies led to the identification of five school contextual factors – the 5Essential Supports – determined to be critical to school success: (1) effective leaders, (2) collaborative teachers, (3) involved families, (4) supportive environment, and (5) ambitious instruction. The framework of the 5Essential Supports served as a theoretical basis for a survey effort designed to measures and report on facets of school culture that could then be used by school leaders and practitioners to guide school improvement efforts. Research related to the 5Essential Supports consistently demonstrates a strong relationship between the presence of these supports and gains in student achievement. Led by Dr. James McMillan and Dr. Charol Shakeshaft from VCU’s School of Education, the purpose of this MERC study was (1) to develop a shortened version of the 5Essentials staff climate survey for the Metropolitan Educational Research Consortium schools, (2) to pilot test the new survey with teachers and administrators, and (3) to determine effective methods of dissemination to support schools use f the survey data for school improvement purposes. The piloting and validation phase of the study demonstrated that the core constructs underlying the 5Essentials maintained high levels of validity and reliability in the shortened version. MERC also piloted and received feedback from school leaders on formats for reporting school climate results
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