Angular and energy dependence of (e,e′)(e,e^{\prime}) cross sections for orbital 1+^+ excitations

The main features of the $(e,e^{\prime})$ cross sections of low-lying orbital excitations with $K^{\pi} = 1^+$ in heavy deformed nuclei are studied in RPA on the example of $^{156}$Gd. The dependence of the DWBA E2 and M1 cross sections on the scattering angle $0^{\circ} < \theta < 180 ^{\circ}$ and incident electron energy $E_i < 210$ MeV is analyzed in PWBA. The cross section is larger for M1 than for E2 transitions at any angle if $E_i < 30$ MeV. The longitudinal (Coulomb) C2 excitation dominates the E2 response for $5^{\circ} < \theta < 170 ^{\circ}$. Only transverse M1 and E2 excitations compete for $\theta > 175 ^{\circ}$ and the former one is dominant for $q < 1.2$ fm$^{-1}$. The M1 response is almost purely orbital up to $q = 1.4$ fm$^{-1}$ even in backward scattering. Qualitative PWBA estimates based on the $q$-dependence of the form factors alone are not able to predict some important features of the $(e,e^{\prime})$ cross sections stemming from the strong magnetic and orbital character of the studied 1$^+$ excitations. The expectation for M1 over E2 dominance in backward scattering should not be extended to higher momentum transfers and incident energies.Comment: Latex, 28 pages, 12 postscript figures included using uufile

Pharmacodynamics of isavuconazole in experimental invasive pulmonary aspergillosis: implications for clinical breakpoints

OBJECTIVES: Isavuconazole, a novel triazole antifungal agent, has broad-spectrum activity against Aspergillus spp. and other pathogenic fungi. The isavuconazole exposure–response relationship in experimental invasive pulmonary aspergillosis using galactomannan index (GMI) suppression as a marker of disease clearance was explored. METHODS: The impact of exposure on GMI suppression in persistently neutropenic rabbits treated with isavuconazonium sulphate (isavuconazole-equivalent dosages of 20, 40 or 60 mg/kg every 24 h, after a 90 mg/kg loading dose) for 12 days was linked using mathematical modelling. Bridging to humans using population pharmacokinetic (PK) data from a clinical trial in invasive aspergillosis was performed using Monte Carlo simulations. RESULTS: Mean plasma isavuconazole AUC/MIC (EC(50)) of 79.65 (95% CI 32.2, 127.1) produced a half-maximal effect in GMI suppression. The inhibitory sigmoid E(max) curve dropped sharply after an AUC/MIC of ≥30 and was near maximum (EC(80)) at ∼130. Bridging the experimental PK/pharmacodynamic (PD) target to human population PK data was then used to return to the rabbit model to determine a clinically relevant PD endpoint. The clinical dosing regimen used in the trial would result in a mean GMI of 4.3 ± 1.8, which is a 50% reduction from the starting GMI in the experiment. CONCLUSIONS: The clinical trial results showing the non-inferiority of isavuconazole to voriconazole for all-cause mortality further support the PK-PD endpoint, thereby demonstrating the usefulness of the rabbit model and endpoint for isavuconazole and implications on interpretive breakpoints. Importantly, the analysis supports this model as an important tool for development of antifungal agents

Managing the outsourcing relationship : does management really know what they are getting into?

Outsourcing is the contracting out of some task to a vendor outside of the actual firm itself. It is now considered to be a world wide management tool for revitalizing and reestablishing a corporation. Outsourcing challenges the way top management thinks in terms of the traditional organization versus the more flexible organization consisting of exterior relationships focused on the long-term and an interior relationship which is focused around core competencies. The research for this paper used a case study approach along with personal interviews of top level information technology executives that had recently completed an outsourcing contract. The primary goal of the research was to find what kinds of challenges today\u27s management faces when they first attempt to outsource a portion of work. A secondary point of interest was how the expectations of the contract met up with the outcome of the project. Other concerns were the advice the respondents would give to other companies, the criteria utilized to evaluate the vendor, and the factors that prompted the organizations to outsource in the first place. Findings suggest that several problems do exist within the outsourcing relationship. The relationship should focus on long-term goals and not short-term cost savings. The decisions that are made must not be dominated by the vendor. The relationship must remain a partnership at all times

Effects of the Spin-Orbit and Tensor Interactions on the M1M1 and E2E2 Excitations in Light Nuclei

The effects of varying the spin-orbit and tensor components of a realistic interaction on $M1$ excitation rates and $B(E2)'s$ are studied on nuclei in the $0p$ and $1s-0d$ shells. Not only the total $M1$ but also the spin and orbital parts separately are studied. The single-particle energies are first calculated with the same interaction that is used between the valence nucleons. Later this stringent condition is relaxed somewhat and the $1s$ level is raised relative to $0d$. For nuclei up to $^{28}Si$, much better results i.e stronger $B(M1)$ rates are obtained by increasing the strength of the spin-orbit interaction relative to the free value. This is probably also true for $^{32}S$, but $^{36}Ar$ presents some difficulties. The effects of weakening the tensor interaction are also studied. On a more subtle level, the optimum spin-orbit interaction in the lower half of the $s-d$ shell, as far as $M1$ excitations are concerned, is substantially larger than the difference $E(J=3/2^+)_1-E(J=5/2^+)_1=5.2~MeV$ in $^{17}O$. A larger spin-orbit splitting is also needed to destroy the triaxiality in $^{22}Ne$. Also studied are how much $M1$ orbital and spin strength lies in an observable region and how much is buried in the grass at higher energies. It is noted that for many nuclei the sum $B(M1)_{orbital}+B(M1)_{spin}$ is very close to $B(M1)_{total}$, indicating that the summed cross terms are very small.Comment: 39 pages, revtex 3.

RAPID: Assessing Tsunami Impacts on the Benthic Community of Robinson Crusoe Island

This RAPID project will assess the subtidal ecological impacts of the tsunami that struck Robinson Crusoe Island on 27 February 2010 with support from the Biological Oceanography Program and the Office of International Science and Engineering/Americas. It will take advantage of baseline data collected as part of an ongoing Chilean research project. Robinson Crusoe Island belongs to the Juan Fernandez archipelago, some 600 km west of the coast of Chile in the southeast Pacific. The island group is unique for its high level of marine and terrestrial endemism, including a fishery for the prized Robinson Crusoe Island lobster, Jasus frontalis. Since 2008, a Chilean team of investigators has provided some of the first quantitative data linking nearshore oceanographic conditions to the benthic community of this temperate oceanic island. The Chilean project established study sites around the island at which temperature loggers, current meters, and lobster post-larval collectors have been placed, and which serve as focal points for benthic and planktonic sampling. However, the tsunami devastated the island\u27s waterfront village and swept away the Chilean research team\u27s field lab, equipment and housing. With as much as 1.5 years of ecological and oceanographic data collected prior to the tsunami, a rapid response collaboration between US and Chilean investigators will hasten the recovery of the Chilean project and provide an unusual opportunity for a rigorous before-after assessment of the tsunami\u27s effects on important components of the benthic community, including the island\u27s key fishery species. It is critical to initiate short-term assessments as soon as possible, and at the same time, reestablish the infrastructure and capacity to continue long-term sampling, which was part of the original Chilean project. This RAPID project will focus on objectives for which pre-tsunami data exist: (1) Census lobster dens where social groups of lobsters were previously tagged; (2) retrieve and redeploy artificial post-larval settlement collectors; (3) conduct benthic suction samples of the cobble-dwelling invertebrate assemblage; (4) conduct video-monitored predation experiments to assess changes in the predation pressure by fish and octopus; (5) resume tissue sampling of planktonic larvae and benthic adults for molecular genetic analysis.This project is relevant to an understanding of the resilience of marine ecosystems, biodiversity and fisheries to agents of natural disturbance of different scales and magnitudes. Current understanding of rare, short-lived, but potentially extreme natural disturbances are inherently poor. To date, documentation of the ecological impact of tsunamis on marine benthic environments is mostly restricted to the relatively recent Christmas tsunami of 2004 that largely affected tropical benthic communities with considerable reductions in coral reefs and associated biota in the coastal Indo-west Pacific. There are no published studies of the impact of a tsunami on the benthic assemblages of temperate oceanic islands. The small size and isolation of the Juan Fernandez archipelago dramatically increases the extinction risk for shallow marine populations and communities. Large numbers of demersal fishes and invertebrates were stranded during the tsunami. Some components of the benthic community are likely to be more vulnerable than others to this kind of disturbance.Broader Impacts: This research will leverage public interest in the dramatic terrestrial impacts of tsunamis, drawing them into the marine realm through geo-tagged, metadata-rich photos and video. Geo-tagging is the process of adding geographical identification to media, metadata that will be particularly helpful to learners who are not accustomed to thinking about submarine locations. This component of the project will add scientific information to the media, allowing users to get instantaneous information about the scenes they are observing by placing their cursors on the images or video. To ensure that the data and information are audience-appropriate, the investigators will work with the Centers for Ocean Sciences Education Excellence (COSEE) - Ocean Systems (OS) program at University of Maine. COSEE-OS has vast experience in working with scientists to frame their research through interactive media that is highly effective with educators. The media will be directly tied to the National Geographic Society\u27s Ocean Literacy campaign, specifically addressing the concept Coastal regions are susceptible to natural hazards . This will provide broad audiences an opportunity to understand the role of ecological disturbance as a force structuring populations and communities, both above and below sea level

The effect of elevated temperature on the wear of stainless steel in contact with tungsten carbide

The bearings in the air motors of modern jet aircraft engines must operate dry in hostile conditions at temperatures up to 500° C, where the thrust races in the actuators operate at temperatures up to 300° C. One of the few metallurgical combinations which can function efficiently under these conditions is martensitic stainless steel on tungsten carbide. The work described was initiated to isolate the wear mechanisms of two such steels in contact with tungsten carbide at temperatures up to 500° C. Experiments were carried out on angular contact bearings similar to these used in service, where both rolling and sliding is present and also for pure sliding conditions using a pin-on-disc apparatus. Wear measurements of the bearings were obtained with wear rates, friction and surface temperatures from the pin-on-disc machine for a series of loads and speeds. Extensive X-ray diffraction analysis was carried out on the wear debris, with also S.E.M. analysis and hardness tests on the worn surfaces along with profilometry measurements of the disc. The oxidational parameters of the steel were obtained from measurements of oxide growth rates by ellipsometry. Three distinct mechanisms of wear were established and the latter two were found to be present in both configurations. These involve an oxidational-abrasive mechanism at loads below 40 N with pin surface temperatures up to about 300 °C, with the mechanism changing to severe wear for higher loads. As the temperature increases a third wear mechanism appears due to transfer of relatively soft oxide films to the steel surface reducing the wear rate. Theoretical K factors were derived and compared with experimental values which were found to be in good agreement for the severe wear mechanism. The pin-on-disc experiments may be useful as a screening test for material selection, without the considerable cost of producing the angular contact bearings

Competing electric and magnetic excitations in backward electron scattering from heavy deformed nuclei

Important $E2$ contributions to the $(e,e^{\prime})$ cross sections of low-lying orbital $M1$ excitations are found in heavy deformed nuclei, arising from the small energy separation between the two excitations with $I^{\pi}K = 2^+1$ and 1$^+1$, respectively. They are studied microscopically in QRPA using DWBA. The accompanying $E2$ response is negligible at small momentum transfer $q$ but contributes substantially to the cross sections measured at $\theta = 165 ^{\circ}$ for $0.6 < q_{\rm eff} < 0.9$ fm$^{-1}$ ($40 \le E_i \le 70$ MeV) and leads to a very good agreement with experiment. The electric response is of longitudinal $C2$ type for $\theta \le 175 ^{\circ}$ but becomes almost purely transverse $E2$ for larger backward angles. The transverse $E2$ response remains comparable with the $M1$ response for $q_{\rm eff} > 1.2$ fm$^{-1}$ ($E_i > 100$ MeV) and even dominant for $E_i > 200$ MeV. This happens even at large backward angles $\theta > 175 ^{\circ}$, where the $M1$ dominance is limited to the lower $q$ region.Comment: RevTeX, 19 pages, 8 figures included Accepted for publication in Phys Rev

Non-Linear Interactions between Consumers and Flow Determine the Probability of Plant Community Dominance on Maine Rocky Shores

Although consumers can strongly influence community recovery from disturbance, few studies have explored the effects of consumer identity and density and how they may vary across abiotic gradients. On rocky shores in Maine, recent experiments suggest that recovery of plant- or animal- dominated community states is governed by rates of water movement and consumer pressure. To further elucidate the mechanisms of consumer control, we examined the species-specific and density-dependent effects of rocky shore consumers (crabs and snails) on community recovery under both high (mussel dominated) and low flow (plant dominated) conditions. By partitioning the direct impacts of predators (crabs) and grazers (snails) on community recovery across a flow gradient, we found that grazers, but not predators, are likely the primary agent of consumer control and that their impact is highly non-linear. Manipulating snail densities revealed that herbivorous and bull-dozing snails (Littorina littorea) alone can control recovery of high and low flow communities. After ∼1.5 years of recovery, snail density explained a significant amount of the variation in macroalgal coverage at low flow sites and also mussel recovery at high flow sites. These density-dependent grazer effects were were both non-linear and flow-dependent, with low abundance thresholds needed to suppress plant community recovery, and much higher levels needed to control mussel bed development. Our study suggests that consumer density and identity are key in regulating both plant and animal community recovery and that physical conditions can determine the functional forms of these consumer effects