3,129 research outputs found
Acoustically monitoring the rhythms of biodiversity in agroecosystems
Author institution (Hoy): Department of Entomology, The Ohio State Universit
Auxiliary-field quantum Monte Carlo calculations of molecular systems with a Gaussian basis
We extend the recently introduced phaseless auxiliary-field quantum Monte
Carlo (QMC) approach to any single-particle basis, and apply it to molecular
systems with Gaussian basis sets. QMC methods in general scale favorably with
system size, as a low power. A QMC approach with auxiliary fields in principle
allows an exact solution of the Schrodinger equation in the chosen basis.
However, the well-known sign/phase problem causes the statistical noise to
increase exponentially. The phaseless method controls this problem by
constraining the paths in the auxiliary-field path integrals with an
approximate phase condition that depends on a trial wave function. In the
present calculations, the trial wave function is a single Slater determinant
from a Hartree-Fock calculation. The calculated all-electron total energies
show typical systematic errors of no more than a few milli-Hartrees compared to
exact results. At equilibrium geometries in the molecules we studied, this
accuracy is roughly comparable to that of coupled-cluster with single and
double excitations and with non-iterative triples, CCSD(T). For stretched bonds
in HO, our method exhibits better overall accuracy and a more uniform
behavior than CCSD(T).Comment: 11 pages, 5 figures. submitted to JC
Survey of Ground-Dwelling Predaceous and Parasitic Arthropods in Cabbage Fields in Upstate New York
During 1979 and 1981, populations of ground-dwelling predators and parasites in research and commercial cabbage fields in upstate New York were assessed by pitfall trapping to determine species composition, abundance, phenology, and the impact of insecticides on them. Staphylinidae, Phalangida, Carabidae, and Araneida were consistently the most abundant predaceous taxa. Carabids and Staphylinids together comprised 75.9 and 74.1% of all predaceous or parasitic insects in commercial fields during 1979 and 1981, respectively. One of the 32 species of Carabidae captured, Pterostichus melanarius (Illiger), accounted for >50% of the total number of Carabidae. Total number of predators and parasites tended to decline from July through September in both treated and untreated fields, but this decline was hastened by the use of broad-spectrum insecticide
Economic Impact and Control of Wading Birds at Arkanas Minnow Ponds
Esophageal/stomach contents of 172 little blue herons (Egretta caerulea), great egrets (Casmerodius albus), snowy egrets (Egretta thula), and great blue herons (Ardea herodias) were analyzed to estimate their consumption of golden shiners. Mean and maximum number of golden shiners consumed/bird, as well as the mean total length of golden shiners consumed by each wading bird species was determined. Loss estimates varied by wading bird species and ranged from 1.12/bird/feeding. Loss estimates reflect the severity of problems with wading birds on minnow ponds and the need to reduce losses by use of effective control methods
Transformation Plans for Optimizing Military Vehicle Testing
The U.S. Army Aberdeen Test Center is a leading Department of Defense developmental test center and test range. A majority of the testing conducted at the Aberdeen Test Center is automotive in nature. Due to recent conflicts around the world, the U.S. Armed Services need to field new armored systems rapidly. The rapid deployment of automotive systems has caused the Department of Defense test community and the Aberdeen Test Center in particular to reevaluate and redefine traditional test plans and practices in order to maximize the amount of valid and pertinent data obtained from shortened test schedules. As a result, this thesis studies new transformation plans to provide ways to optimize military test plans. These transformation plans take into account existing military vehicle data from multiple sources including the Aberdeen Test Center's automotive road courses. These transformation plans are not only useful for shortened military tests, but can also be easily employed in developing test plans for private industry customers as well as long term test projects. The benefits in all cases are the same: an optimized test plan for automotive endurance operations
Integrating Time Into Family Business Research: Using Random Coefficient Modeling to Examine Temporal Influences on Family Firm Ambidexterity
Organizational ambidexterity refers to a firm’s ability to pursue both exploitation and exploration orientations. Despite research that suggests ambidexterity is a critical phenomenon in family firms, few studies directly examine the role of ambidexterity over time in family business. This study examines how family firm ambidexterity changes over time as a result of temporal-, firm-, and industry-level factors. We find that family firm ambidexterity is stable over time, punctuated by dramatic changes. We also find that the level of innovation required to compete in an industry is a predictor of changes in exploration versus exploitation over time among family firms.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline
International Strategic Alliances: A Tale of Two Firms
Firms seeking to enter international markets have increasingly opted for cooperative relationships with business partners as a mode of easing and promoting market entry. This study examines the expansion of two small/medium-sized enterprises (SMEs), organizations with· 30 to 500 employees, in the U.S. and in Mexico. The study compares and contrasts the nearly simultaneous expansion of a U.S.-based franchisor into Mexico and that of a Mexican firm into the U.S. In addition to its implications regarding strategic alliance as an international entry mode for SMEs, this study also contributes toward the quest for longitudinal theory building. Given that this was the first international expansion for both principal entities, a major outcome of the study is documentation of the importance of both partnership and planning for successful international activities
Microfabrication of Ceramics by Co-extrusion
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65777/1/j.1151-2916.1998.tb02307.x.pd
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