Acoustic scattering from a strained region

A composite material consists of a rubber filled with gas-filled microspheres. In underwater applications it is compressed hydrostatically by a pressure that may be not insignificant compared with the shear modulus of the rubber, so large strains are produced around each spherical inclusion. When these spherical inclusions scatter an incident acoustic wave, the strained region around an inclusion has had its elastic properties altered by the large static strain. Thales Underwater Systems asked the Study Group to address the question of how this strained region affects the elastic scattering, bearing in mind that the dynamic shear modulus differs from its static value

Mesopelagic fishes dominate otolith record of past two millennia in the Santa Barbara Basin.

The mesopelagic (200-1000 m) separates the productive upper ocean from the deep ocean, yet little is known of its long-term dynamics despite recent research that suggests fishes of this zone likely dominate global fish biomass and contribute to the downward flux of carbon. Here we show that mesopelagic fishes dominate the otolith (ear bone) record in anoxic sediment layers of the Santa Barbara Basin over the past two millennia. Among these mesopelagic fishes, otoliths from families Bathylagidae (deep-sea smelts) and Myctophidae (lanternfish) are most abundant. Otolith deposition rate fluctuates at decadal to centennial time scales and covaries with proxies for upper ocean temperature, consistent with climate forcing. Moreover, otolith deposition rate and proxies for temperature and primary productivity show contemporaneous discontinuities during the Medieval Climate Anomaly and Little Ice Age. Mesopelagic fishes may serve as proxies for future climatic influence at those depths including effects on the carbon cycle

Cancers of unknown primary diagnosed during hospitalization: a population-based study

Background: Cancers of Unknown Primary (CUP) are the 3-4th most common causes of cancer death and recent clinical guidelines recommend that patients should be directed to a team dedicated to their care. Our aim was to inform the care of patients diagnosed with CUP during hospital admission. Methods: Descriptive study using hospital admissions (Scottish Morbidity Record 01) linked to cancer registrations (ICD-10 C77-80) and death records from 1998 to 2011 in West of Scotland, UK (population 2.4 m). Cox proportional hazards models were used to assess effects of baseline variables on survival. Results: Seven thousand five hundred ninety nine patients were diagnosed with CUP over the study period, 54.4% female, 67.4% aged ≥ 70 years, 36.7% from the most deprived socio-economic quintile. 71% of all diagnoses were made during a hospital admission, among which 88.6% were emergency presentations and the majority (56.3%) were admitted to general medicine. Median length of stay was 15 days and median survival after admission 33 days. Non-specific morphology, emergency admission, age over 60 years, male sex and admission to geriatric medicine were all associated with poorer survival in adjusted analysis. Conclusions: Patients with a diagnosis of CUP are usually diagnosed during unplanned hospital admissions and have very poor survival. To ensure that patients with CUP are quickly identified and directed to optimal care, increased surveillance and rapid referral pathways will be required

U.S. Demand for Source–Differentiated Shrimp: A Differential Approach

Estimates of price and scale elasticities for U.S. consumed shrimp are derived using aggregate shrimp data differentiated by source country. Own-price elasticities for all countries had the expected negative signs, were statistically significant, and inelastic. The scale elasticities for all countries were positive and statistically significant at the 1% level with only the United States and Ecuador having scale elasticities of less than one. For the most part, the compensated demand effects showed that most of the cross-price effects were positive. Our results also suggest that despite the countervailing duties imposed by the United States, shrimp demand was fairly stable.CBS, conditional demand, countervailing duty, imports, scale elasticity, shrimp, Agribusiness, Farm Management, Food Consumption/Nutrition/Food Safety, Production Economics, C32, D12, Q13, Q22,

Beef carcass grading and evaluation (1993)

Evaluation of beef quality and composition is important to cattle producers, meat packers and retailers, and consumers. Consumers desire cuts of beef that are lean, nutritious, and possess desirable eating characteristics. Meat researchers have developed reliable methods for measuring the factors that influence eating characteristics and factors affecting yield of lean cuts. Using these evaluation techniques, producers and packers can produce and sell carcasses that meet consumer demand.Reviewed October 1993 -- Extension website

Space Station Data Management System Assessment Methodology

A computer-aided modeling tool and methodology was developed and is currently being used to assess candidate designs for the Space Station Data Management System (DMS). The DMS will be a complex distributed computer system including processors, storage devices, local area networks, and software that will support all processing functions on board the Space Station. The methodology produces assessments of the performance, reliability, cost, and physical attributes of the candidate designs. This paper describes the architecture and design of the modeling tool and presents the modeling methodology

Evolution of Geometric Sensitivity Derivatives from Computer Aided Design Models

The generation of design parameter sensitivity derivatives is required for gradient-based optimization. Such sensitivity derivatives are elusive at best when working with geometry defined within the solid modeling context of Computer-Aided Design (CAD) systems. Solid modeling CAD systems are often proprietary and always complex, thereby necessitating ad hoc procedures to infer parameter sensitivity. A new perspective is presented that makes direct use of the hierarchical associativity of CAD features to trace their evolution and thereby track design parameter sensitivity. In contrast to ad hoc methods, this method provides a more concise procedure following the model design intent and determining the sensitivity of CAD geometry directly to its respective defining parameters