2,760 research outputs found
Light Trap Records of \u3ci\u3ePhyllophaga\u3c/i\u3e (Coleoptera: Scarabaeidae) in Wisconsin, 1984-1987
Phyllophaga adults (June beetles) were surveyed from 1984 through 1987 at five locations in Wisconsin using black light traps. Data were collected at each location for three consecutive years. A total of 9,259 specimens representing 13 species were collected during the survey. Species captured, sex ratios, and flight periods for abundant species were recorded for each location. Species abundance differed from previous surveys of Phyllophaga in Wisconsin. Possible reasons for observed shifts in species abundance are discussed
Hybrid Group IV Nanophotonic Structures Incorporating Diamond Silicon-Vacancy Color Centers
We demonstrate a new approach for engineering group IV semiconductor-based
quantum photonic structures containing negatively charged silicon-vacancy
(SiV) color centers in diamond as quantum emitters. Hybrid SiC/diamond
structures are realized by combining the growth of nanoand micro-diamonds on
silicon carbide (3C or 4H polytype) substrates, with the subsequent use of
these diamond crystals as a hard mask for pattern transfer. SiV color
centers are incorporated in diamond during its synthesis from molecular diamond
seeds (diamondoids), with no need for ionimplantation or annealing. We show
that the same growth technique can be used to grow a diamond layer controllably
doped with SiV on top of a high purity bulk diamond, in which we
subsequently fabricate nanopillar arrays containing high quality SiV
centers. Scanning confocal photoluminescence measurements reveal optically
active SiV lines both at room temperature and low temperature (5 K) from
all fabricated structures, and, in particular, very narrow linewidths and small
inhomogeneous broadening of SiV lines from all-diamond nano-pillar arrays,
which is a critical requirement for quantum computation. At low temperatures (5
K) we observe in these structures the signature typical of SiV centers in
bulk diamond, consistent with a double lambda. These results indicate that high
quality color centers can be incorporated into nanophotonic structures
synthetically with properties equivalent to those in bulk diamond, thereby
opening opportunities for applications in classical and quantum information
processing
Predispositions and the Political Behavior of American Economic Elites: Evidence from Technology Entrepreneurs
Economic elites regularly seek to exert political influence. But what policies do they support? Many accounts implicitly assume economic elites are homogeneous and that increases in their political power will increase inequality. We shed new light on heterogeneity in economic elites' political preferences, arguing that economic elites from an industry can share distinctive preferences due in part to sharing distinctive predispositions. Consequently, how increases in economic elites' influence affect inequality depends on which industry's elites are gaining influence and which policy issues are at stake. We demonstrate our argument with four original surveys, including the two largest political surveys of American economic elites to date: one of technology entrepreneurs—whose influence is burgeoning—and another of campaign donors. We show that technology entrepreneurs support liberal redistributive, social, and globalistic policies but conservative regulatory policies—a bundle of preferences rare among other economic elites. These differences appear to arise partly from their distinctive predispositions
Photocathode device using diamondoid and cesium bromide films
A photocathode structure is presented that shows promise for use in high brightness electron sources. The structure consists of a metal substrate, a monolayer of a diamondoid derivative, and a thin film of cesium bromide. Diamondoid monolayers reduce the energy spread of electron emitters, while cesium bromide increases the yield and stability of cathodes. We demonstrate that the combined structure retains these properties, producing an emitter with lower energy spread than the corresponding cesium bromide emitter (1.06?eV versus 1.45?eV) and higher yield and stability than un-coated diamondoid emitters
Elections and Ethnic Civil War
Existing research on how democratization may influence the risk of civil war tends to consider only changes in the overall level of democracy and rarely examines explicitly the postulated mechanisms relating democratization to incentives for violence. The authors argue that typically highlighted key mechanisms imply that elections should be especially likely to affect ethnic groups’ inclination to resort to violence. Distinguishing between types of conflict and the order of competitive elections, the authors find that ethnic civil wars are more likely to erupt after competitive elections, especially after first and second elections following periods of no polling. When disaggregating to the level of individual ethnic groups and conflicts over territory or government, the authors find some support for the notion that ethno-nationalist mobilization and sore-loser effects provoke postelectoral violence. More specifically, although large groups in general are more likely to engage in governmental conflicts, they are especially likely to do so after noncompetitive elections. Competitive elections, however, strongly reduce the risk of conflict. </jats:p
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Two sword lengths apart: Credible commitment problems and physical violence in democratic national legislatures
Ideally, national legislatures in democracies should be venues for peacefully resolving conflicts between opposing groups. However, they can become places of physical violence. Such violence can be an indication that countries’ legislative institutions are functioning far from the democratic ideal of being venues for peaceful conflict reconciliation. In some cases, such as Ukraine prior to the 2014 outbreak of armed conflict in the country’s east and south, violence can indicate and possibly fuel deeper political divisions. In this first global study of legislative violence, I show that brawls are more likely when legislators find it difficult to credibly commit to follow peaceful bargains. Credible commitment problems are more acute in countries with new democracies and disproportionate electoral outcomes – that is, when electoral votes for parties do not closely correspond to the legislative seats they are given. I find robust support for this argument by first examining a case study of legislative violence in the antebellum United States Senate. Pro- and anti-slavery senators became increasingly unable to maintain credible commitments in the lead-up to the 1856 caning of Senator Charles Sumner as the allocation of seats in the legislative body became more disproportional. Second, I find further support for my argument in a new global dataset of contemporary instances of violence in national legislatures. In addition, I find strong evidence that violence is more likely in legislatures with small minority governments. Despite reasonable expectations, civil wars are not associated with more legislative violence
Dream capitalism
John Tomasi’s Free Market Fairness represents an heroic attempt to bridge the gap between Rawlsian ‘high liberals’ and the advocates of classical liberalism/contemporary libertarianism. I argue that Tomasi’s project fails, above all because it cannot give a compelling account of contemporary (American) capitalism or of its capacity to deliver free market fairness
Does compulsory voting increase support for leftist policy?
Citizens unequally participate in referendums, and this may systematically bias policy in favor of those who vote. Some view compulsory voting as an important tool to alleviate this problem, whereas others worry about its detrimental effects on the legitimacy and quality of democratic decision making. So far, however, we lack systematic knowledge about the causal effect of compulsory voting on public policy. We argue that sanctioned compulsory voting mobilizes citizens at the bottom of the income distribution and that this translates into an increase in support for leftist policies. We empirically explore the effects of a sanctioned compulsory voting law on direct-democratic decision making in Switzerland. We find that compulsory voting significantly increases electoral support for leftist policy positions in referendums by up to 20 percentage points. We discuss the implications of these results for our understanding of the policy consequences of electoral institutions
Keck Interferometer autoaligner: algorithms and techniques
The Keck Interferometer includes an autoalignment system consisting of pop-up targets located at strategic locations along the beam trains of each arm of the instrument along with a sensor and control system. We briefly describe the hardware of the system and then proceed to a description of the two operational modes of the system. These are: 1) to provide an initial alignment of the coude paths in each arm, and 2) to recover coude alignments between changes of the static delay sled positions. For the initial alignment mode, we review the system performance requirements along with the software used for image acquisition and centroiding. For coudé alignment recovery, we describe beam-train surveys through the static delay (Long Delay Line) and criteria for a successful recovery of a coudé alignment. Finally, we describe the results of testing of the autoalignment system
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