Dungeness crab research program

In 1974, the California State Legislature, recognizing the problem of low yields from the Dungeness crab resource of central California, directed the Department of Fish and Game to conduct an investigation into the causes of the decline. The Operations Research Branch of the Department has conducted preliminary studies and field operations necessary to formulate the Dungeness Crab Research Program. The objectives, research design, and work plans are presented for a 4-year program from July 1, 1975 through August 31, 1979. (38pp.

Electronic Properties of Strained Si/Ge Core-Shell Nanowires

We investigated the electronic properties of strained Si/Ge core-shell nanowires along the [110] direction using first principles calculations based on density-functional theory. The diameter of the studied core-shell wire is up to 5 nm. We found the band gap of the core-shell wire is smaller than that of both pure Si and Ge wires with the same diameter. This reduced band gap is ascribed to the intrinsic strain between Ge and Si layers, which partially counters the quantum confinement effect. The external strain is further applied to the nanowires for tuning the band structure and band gap. By applying sufficient tensile strain, we found the band gap of Si-core/Ge-shell nanowire with diameter larger than ~3 nm experiences a transition from direct to indirect gap.Comment: 4 figure

Experimental and Numerical Investigation of Thermal Performance of a Crossed Compound Parabolic Concentrator with PV Cell

Crossed compound parabolic concentrator (CCPC) is a solar energy device used to increase the photovoltaic (PV) cell electrical power output. CCPC’s thermal and optical performance issues are equally important for a PV cell or module to work under a favourable operating condition. However, most work to-date is emphasised on its optical performance paying a little attention to the thermal characteristics. In this contribution, we investigate the thermal performance of a CCPC with PV cell at four different beam incidences (0o, 10o, 20o, 30o and 40o). Initially, experiment is performed in the indoor PV laboratory at the University of Exeter with 1kW/m2 radiation intensity. 3D simulations are carried out to first validate the predicted data and then to characterise the overall performance. Results show that the temperature in the PV silicon layer is the highest at 0o and 30o, with the top glass cover of CCPC having the lowest temperature at all the incidences. The temperature and optical efficiency profiles at the various incidences predicted by simulation show very good agreement with the measurements, especially at 0o incidence. This study provides useful information for understanding the coupled optical-thermal performance of the CCPC with PV cell working at various conditions

Natural convective heat transfer in a walled CCPC with PV cell

The free convective heat transfer phenomenon in an isolated, walled CCPC with PV cell is studied experimentally at 1000 W/m2 irradiance and 28.5 °C ambient temperature as well as 0°, 10°, 20°, 30° and 40° incidences in indoor laboratory by using solar simulator. Then a series of numerical simulations are launched to estimate the CCPC natural heat transfer behaviour and optical performance based on steady heat transfer and laminar flow models with grey optical option. It is identified that the heat transfer and optical performances of CCPC are dependent on the incidence. Especially, the PV cell is subject to the highest temperature at an incidence less than 20°, and otherwise the top glass cover is with the highest temperature. The predicted temperatures, Nusselt numbers and heat loss ratios are consistent with the experimental observations basically, especially at the incidence less than 20° with (−10.1~+3) % error in temperature, (−35.6~+12.6) % in Nusselt number, and (−1.2~+20.5) % in CCPC wall heat loss ratio. The optical parameters predicted agree very well with the measurements. The heat loss from the CCPC walls accounts for nearly 60% of the total incoming solar irradiance and should be paid significant attention in the design of CCPC

Inefficiency and productivity growth in banking: a comparison of stochastic econometric and thick frontier methods

A comparison of alternative methods for estimating inefficiency and productivity growth in banking, showing that inefficiencies are sufficiently large to dominate scale economies and that measured technological progress has been small, or even negative, as a result of institutional events that occurred during 1977-88.Banks and banking - Costs ; Production (Economic theory)

Dungeness crab research program: Report for the Year 1976

All larval stages of the 1976 year class, with the exception of the 5th zoeal stage, were found in Gu1f waters January through March. The first post-larval stage was collected in San Pablo Bay in May. Fifty percent of 1976 year class crabs entered the Bay complex as compared to nearly 80% in 1975. The 1976 year class appears relatively weak. No electrophoretic polymorphism was found in Cancer magister to be of value in Dungeness crab population determinations. Multi-variate correlations comparing crab landings with an array of oceanographic parameters and the crab density dependent factor were computer-run for both northern and central California. The most significant correlating factors at the time late stage larvae prevail were sea level and atmospheric pressure for central California and, for northern California, the density dependent factor and sea surface temperature. Female crabs held at controlled temperatures indicated gonad maturation and spawning may be induced by increased temperature. Analyses of crab tissues revealed burdens of petroleum hydrocarbons, silver, selenium, cadmium, and PCB's higher in central California crabs, while DDE was found in higher amounts in northern California crab tissue. Thru-flow culture systems were developed which should yield about 163 megalopae of Dungeness crabs in 63 days from 1,200 laboratory hatched zoeae.(46pp.

Growth Econometrics

This paper provides a survey and synthesis of econometric tools that have been employed to study economic growth. While these tools range across a variety of statistical methods, they are united in the common goals of first, identifying interesting contemporaneous patterns in growth data and second, drawing inferences on long-run economic outcomes from cross-section and temporal variation in growth. We describe the main stylized facts that have motivated the development of growth econometrics, the major statistical tools that have been employed to provide structural explanations for these facts, and the primary statistical issues that arise in the study of growth data. An important aspect of the survey is attention to the limits that exist in drawing conclusions from growth data, limits that reflect model uncertainty and the general weakness of available data relative to the sorts of questions for which they are employed.

A Killing tensor for higher dimensional Kerr-AdS black holes with NUT charge

In this paper, we study the recently discovered family of higher dimensional Kerr-AdS black holes with an extra NUT-like parameter. We show that the inverse metric is additively separable after multiplication by a simple function. This allows us to separate the Hamilton-Jacobi equation, showing that geodesic motion is integrable on this background. The separation of the Hamilton-Jacobi equation is intimately linked to the existence of an irreducible Killing tensor, which provides an extra constant of motion. We also demonstrate that the Klein-Gordon equation for this background is separable.Comment: LaTeX, 14 pages. v2: Typo corrected and equation added. v3: Reference added, introduction expanded, published versio

Skin Necrosis Distal to a Rapid Infusion Catheter: Understanding Possible Complications of Large-bore Vascular Access Devices.

Rapid infusion catheters (RICs) allow expedient conversion of peripheral intravenous (PIV) catheters to peripheral sheaths; however, little is known about potential complications. In this case, a 64-year-old male polytrauma patient had a 20-gauge PIV catheter in the right cephalic vein upsized to an 8.5 French (Fr) RIC without incident during an arrest with pulseless electrical activity (PEA). On RIC post-placement day two, the patient developed edema and ecchymosis extending from the right dorsal mid-hand to the antecubital fossa, just distal to the RIC insertion point. Compartments were soft; the volar surface (including an arterial line location), fingers, and upper arm were normal. The RIC flushed and returned blood appropriately. Ultrasound revealed a noncompressible cephalic vein either related to the catheter or thrombosis, and imaging of the hand showed an ulnar styloid fracture and a minimally displaced triquetral fracture. The RIC was removed immediately. Over the next week, the areas of ecchymosis developed bullae and then sloughed, leaving open wounds extending into the dermis. The patient later expired from unrelated causes. The area and timing of the skin necrosis were highly suspicious for a catheter-associated complication, despite the presence of the arterial line and small distal fractures. The necrosis was potentially due to thrombosis of the superficial venous outflow system, leading to congestion and skin compromise, but we found no similar reports. Alternatively, the catheter may have ruptured the vein and caused a gravity-dependent ecchymosis, but the volar surface was not impacted, and the catheter was functioning properly. The RIC may also have encroached on the arterial space, decreasing flow, but we would have expected distal hand changes. The only published reports we could find on RIC complications involved a lost guide wire, fragmentation of a catheter during placement, and a case of compartment syndrome, raising the question of whether skin necrosis is truly a rare event or simply underreported with the RIC. Although the exact causal relationship remains unknown in our case, RICs should be removed as soon as possible after immediate stabilization