587 research outputs found

    Provincial Reconstruction Teams: How Do We Know They Work?

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    Over the past 6 years, provincial reconstruction teams (PRTs) have played a growing role in the U.S. counterinsurgency effort in Afghanistan. PRTs are one of several organizations working on reconstruction there, along with civilian development agencies, including the U.S. Agency for International Development, numerous nongovernmental organizations, and the Afghan government’s National Solidarity Program. Perhaps unsurprisingly, something of a debate has emerged over whether PRTs are needed. The authors argue that civilian reconstruction agencies cannot do the same job as the PRTs. While these agencies remain essential for long-term economic and political development, the PRTs conduct reconstruction in ways that help create stability in the short term. Absent the PRTs, the “build” in clear-hold-build efforts deemed essential to effective counterinsurgency would fall flat. Based on over 2 months of field research in 2007 and 2 months in 2008 by a CNA team with 4 different PRTs—Khost, Kunar, Ghazni, and Nuristan—plus interviews with the leadership of 10 others, the authors recommend that the United States give the PRTs the lead role in reconstruction activities that accompany any surge of military forces into Afghanistan.https://press.armywarcollege.edu/monographs/1355/thumbnail.jp

    COOPERATION AND SOCIAL BONDS IN COMMON VAMPIRE BATS

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    Regurgitated food sharing among vampire bats is a classic textbook example of reciprocity ("reciprocal altruism"). But many authors have contested both the notion that reciprocity explains vampire bat food-sharing and the importance of reciprocity more generally. In Chapter 1, I review the literature on evolutionary explanations of cooperation. I show why reciprocity was once considered important but is now considered rare: overly literal translations of game theory strategies have resulted in problems for both defining and testing reciprocity. In Chapter 2, I examine the relative roles of social predictors of food-sharing decisions by common vampire bats (Desmodus rotundus) under controlled conditions of mixed relatedness and equal familiarity by fasting 20 individuals in 48 trials over two years. The food-sharing network was consistent, symmetrical, and correlated with mutual allogrooming. Non- kin food-sharing patterns were not consistent with harassment or byproduct explanations. I next attempted to manipulate food-sharing decisions in two ways. In Chapter 3, I administered intranasal oxytocin to test for effects on allogrooming and food sharing. I observed that inhaled oxytocin slightly increased the magnitude of food donations within dyads, and the amount of female allogrooming within and across all partners, without increasing number of partners. In Chapter 4, I assessed contingency of food-sharing in 7 female dyads (including four pairs of mother and adult daughters) with prior histories of sharing. To test for evidence of partner switching, I measured dyadic levels of food sharing before and after a treatment period where I prevented dyadic sharing (each bat could only be fed by others). A bat's sharing network size predicted how much food it received in the experiment. When primary donors were excluded, subjects did not compensate with donations from other partners. Yet, food-sharing bonds appeared unaffected by the non-sharing treatment. In particular, close maternal kin were clearly not enforcing cooperation using strict contingency. I argue that any contingencies within such bonds are likely to involve multiple services and long timescales, making them difficult to detect. Simple and dyadic `tit-for-tat' models are unlikely to predict cooperative decisions by vampire bats or other species with stable, mixed kinship, social bonds

    Gas-phase Electronic Spectra of Coronene and Corannulene Cations

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    The effects of age on neophobia and exploration are best described in birds and primates, and broader comparisons require reports from other taxa. Here we present data showing age-dependent exploration in a long-lived social species, the common vampire bat (Desmodus rotundus). A previous study found that vampire bats regurgitated food to partners trapped in a cage. Interestingly, while only a few adult bats visited the trapped bat, in every trial all or most of the eight young males in the colony would visit the trapped bat without feeding it. To test whether this behavioral difference resulted from age class differences in exploration, we compared responses of the bats to a trapped conspecific versus an inanimate novel object. Some adults and young showed interest in trapped conspecifics, but only the young males explored the novel objects. Additional novel object tests in a second captive colony showed that higher rates of novel object exploration were shown by young of both sexes. Our results corroborate past findings from other mammals and birds that age predicts exploration. If age-dependent exploration is indeed adaptive, then the role of age as a predictor of exploration tendency should depend on species-specific life history traits. Finally, because younger vampire bats also appear to have higher exposure to pathogens such as rabies virus, there may be implications for pathogen transmission if younger and more exploratory vampire bats are more likely to feed on novel hosts

    Mass Degeneracies In Self-Dual Models

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    An algebraic restriction of the nonabelian self-dual Chern-Simons-Higgs systems leads to coupled abelian models with interesting mass spectra. The vacua are characterized by embeddings of SU(2)SU(2) into the gauge algebra, and in the broken phases the gauge and real scalar masses coincide, reflecting the relation of these self-dual models to N=2N=2 SUSY. The masses themselves are related to the exponents of the gauge algebra, and the self-duality equation is a deformation of the classical Toda equations.Comment: 10 pages LaTeX (previous copy truncated

    The Ursinus Weekly, March 19, 1962

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    Senior Pete Mackey takes lead in Curtain Club\u27s The Next War • Rector to address Chi Alpha Tuesday • John Piston chosen to edit Weekly; Feature editor elevated Wednesday • Nobel Prize-winner captivates Ursinus: Dr. Pauling advocates peace race for all nations • All-star game pits dorms\u27, frats\u27 best • Political science classes to hear pair of speakers • Band performance shows competence • Obstetrician outlines Caesarian operation • U.C.\u27s student-faculty talent show pleases crowd, helps Campus Chest • Young Republicans to aid Schweiker • Four high school girls discuss student teachers • Meistersingers chosen; 75 students in group • APO to use U.C. women in Spring fashion show • Editorial: And in conclusion • Letters to the editor • Lantern sets deadline • Linus Pauling adds a personal touch • U.C. swimmers gain second place tie in intercollegiates at Penn Saturday • Badminton girls finish eighth perfect campaign • Intramural corner • Curtis I first team to reach finals • Young Demo. conference planned for Philadelphiahttps://digitalcommons.ursinus.edu/weekly/1315/thumbnail.jp

    The Ursinus Weekly, December 11, 1961

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    Harrisburg calls two U.C. seniors for budget talks • Ursinus College\u27s fourteen Who\u27s Who students drawn from entire spectrum of campus activity • Caroling, banquets brighten last college week of 1961 • Weekly circulation up 41% over previous year • Special education speech delivered Tuesday to PSEA • Joint meeting held by science clubs • Senior Bob Allen elected constable in Scranton ward; Ousts incumbent • Christmas communication • Debaters show promise; Sall excels in tourney • College hockey players cited for outstanding skill • Fraternities, sororities spread cheer with orphans\u27 Christmas parties • Editorial: The holiday here • Ursinus in the past • Letters to the editor • Study in noisemaking • Dismal week for Bear cagers • Mark Borak\u27s cage play encouraging; Sophomore uses jump shot effectively • Leber-South volleyball streak at eleven gameshttps://digitalcommons.ursinus.edu/weekly/1307/thumbnail.jp

    The Ursinus Weekly, March 12, 1962

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    Nobel Prize-winner here tonight: Dr. Linus Pauling to address special forum on Science and international relations • Book No more war! Dr. Pauling\u27s credo • Local high school pupils invited to PSEA panel • UC students attend I.C.G. convention • Student-faculty talent show to finish Campus Chest charity drive Friday • College\u27s concert band to perform next Thursday • Lauderdale braces for Spring influx • Civil liberty\u27s Cox visits U.C. campus • Campus Chest activities continue this week • Ursinus invites public to use College Library • St. Pat\u27s twist theme of frosh dance Saturday • Pre-med club to see films depicting Caesarian birth • Editorial: Just this once • Penna. folk festival planned for Harrisburg • Ursinus in the past • Curtain Club offers two plays; One-act shows given last Thursday • Women\u27s hairbreadth victories mark basketball play; Sansenbach stars • High scoring continues; Intramural finish nears • Mermaids win two in week\u27s action • Sports publicist evaluates season • Intramural corner • Cindermen seem strong as five lettermen return • Chief McClure hustles vagrant to county jail • Collegeville tops Phoenix YMCA basketball league • Collegeville firemen take part in Phila. exhibit • Faculty hoopsters triumph in benefit against girls • Graduate grantshttps://digitalcommons.ursinus.edu/weekly/1314/thumbnail.jp

    Sediment-Water Interactions Affecting Dissolved-Mercury Distributions in Camp Far West Reservoir, California

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    Field and laboratory studies were conducted in April and November 2002 to provide the first direct measurements of the benthic flux of dissolved (0.2-micrometer filtered) mercury species (total and methylated forms) between the bottom sediment and water column at three sampling locations within Camp Far West Reservoir, California: one near the Bear River inlet to the reservoir, a second at a mid-reservoir site of comparable depth to the inlet site, and the third at the deepest position in the reservoir near the dam (herein referred to as the inlet, midreservoir and near-dam sites, respectively; Background, Fig. 1). Because of interest in the effects of historic hydraulic mining and ore processing in the Sierra Nevada foothills just upstream of the reservoir, dissolved-mercury species and predominant ligands that often control the mercury speciation (represented by dissolved organic carbon, and sulfides) were the solutes of primary interest. Benthic flux, sometimes referred to as internal recycling, represents the transport of dissolved chemical species between the water column and the underlying sediment. Because of the affinity of mercury to adsorb onto particle surfaces and to form insoluble precipitates (particularly with sulfides), the mass transport of mercury in mining-affected watersheds is typically particle dominated. As these enriched particles accumulate at depositional sites such as reservoirs, benthic processes facilitate the repartitioning, transformation, and transport of mercury in dissolved, biologically reactive forms (dissolved methylmercury being the most bioavailable for trophic transfer). These are the forms of mercury examined in this study. In contrast to typical scientific manuscripts, this report is formatted in a pyramid-like structure to serve the needs of diverse groups who may be interested in reviewing or acquiring information at various levels of technical detail (Appendix 1). The report enables quick transitions between the initial summary information (figuratively at the top of the pyramid) and the later details of methods or results (figuratively towards the base of the pyramid) using hyperlinks to supporting figures and tables, and an electronically linked Table of Contents. During two sampling events, two replicate sediment cores (Coring methods; Fig. 2) from each of three reservoir locations (Fig. 1) were used in incubation experiments to provide flux estimates and benthic biological characterizations. Incubation of these cores provided “snapshots” of solute flux across the sediment-water interface in the reservoir, under benthic, environmental conditions representative of the time and place of collection. Ancillary data, including nutrient and ligand fluxes, were gathered to provide a water-quality framework from which to compare the results for mercury

    The optical counterpart to gamma-ray burst GRB970228 observed using the Hubble Space Telescope

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    Although more than 2,000 astronomical gamma-ray bursts (GRBs) have been detected, and numerous models proposed to explain their occurrence, they have remained enigmatic owing to the lack of an obvious counterpart at other wavelengths. The recent ground-based detection of a transient source in the vicinity of GRB 970228 may therefore have provided a breakthrough. The optical counterpart appears to be embedded in an extended source which, if a galaxy as has been suggested, would lend weight to those models that place GRBs at cosmological distances. Here we report the observations using the Hubble Space Telescope of the transient counterpart and extended source 26 and 39 days after the initial gamma-ray outburst. We find that the counterpart has faded since the initial detection (and continues to fade), but the extended source exhibits no significant change in brightness between the two dates of observations reported here. The size and apparent constancy between the two epochs of HST observations imply that it is extragalactic, but its faintness makes a definitive statement about its nature difficult. Nevertheless, the decay profile of the transient source is consistent with a popular impulsive-fireball model, which assumes a merger between two neutron stars in a distant galaxy.Comment: 11 pages + 2 figures. To appear in Nature (29 May 1997 issue

    The inner membrane complex through development of Toxoplasma gondii and Plasmodium

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    Plasmodium spp. and Toxoplasma gondii are important human and veterinary pathogens. These parasites possess an unusual double membrane structure located directly below the plasma membrane named the inner membrane complex (IMC). First identified in early electron micrograph studies, huge advances in genetic manipulation of the Apicomplexa have allowed the visualization of a dynamic, highly structured cellular compartment with important roles in maintaining the structure and motility of these parasites. This review summarizes recent advances in the field and highlights the changes the IMC undergoes during the complex life cycles of the Apicomplexa
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