19,657 research outputs found
Ceramic composition at Chalcolithic Shiqmim, northern Negev desert, Israel: investigating technology and provenance using thin section petrography, instrumental geochemistry and calcareous nannofossils
Technological innovations in ceramic production and other crafts are hallmarks of the Chalcolithic period (4500–3600 BCE) in the southern Levant, but details of manufacturing traditions have not been fully investigated using the range of analytical methods currently available. This paper presents results of a compositional study of 51 sherds of ceramic churns and other pottery types from the Chalcolithic site of Shiqmim in the northern Negev desert. By applying complementary thin section petrography, instrumental geochemistry and calcareous nannofossil analyses, connections between the raw materials, clay paste recipes and vessel forms of the selected ceramic samples are explored and documented. The study indicates that steps in ceramic manufacturing can be related to both technological choices and local geology. Detailed reporting of the resulting data facilitates future comparative ceramic compositional research that is needed as a basis for testable regional syntheses and to better resolve networks of trade/exchange and social group movement
Cattle breeding in Northern Australia: Revealing how consumers react to new technologies
In Australia, Bos taurus cattle breeds produce high quality meat, superior in taste and tenderness characteristics. Nevertheless, these breeds do not thrive in the Northern Australian environment. Stem cell transplant techniques could improve northern beef cattle breeding programs by facilitating crossbreeding via natural service. Focus groups were used in this study to explore consumer reaction to reproduction technologies and the implications for buying intentions. Findings suggested that consumers may react negatively to unconventional breeding technologies but the degree of this aversion is contingent upon how the technology is described. These findings are relevant for preparation of choice modeling surveys.Non-market valuation, consumers, focus groups, new technologies, beef,
Design comparison of cesium and potassium vapor turbine-generator units for space power
Design comparison of cesium and potassium vapor turbogenerator units for space power plant
Coupling Surfaces and Weak Bernoulli in One and Higher Dimensions
AbstractWe propose a notion of weak Bernoulli in all dimensions which generalizes the usual definition in dimension 1. The key idea is the concept of acoupling surface. We relate this notion to previously studied properties and discuss a number of possible variants in dimension 1. We also show that the Ising model, at low temperature, is weak Bernoulli with an explicit description of the coupling surface
Ingenuous interpretation of elevated blood levels of macromolecular markers of myocardial injury: a recipe for confusion
AbstractSeveral assumptions about elevations of macromolecular markers of myocardial injury in blood require critical consideration. The dichotomy of modest, persistent elevations of troponins I and T as prognostic factors in patients with unstable angina and absent elevations of isoenzymes of creatine kinase is presently unexplained. Factors influencing the appearance of macromolecular markers of myocardial injury in blood are considered, including the need to estimate baseline values, to consider elevations as deviations from baseline rather than simply points within a distribution of baseline values in normal subjects, to recognize operative biochemical and physiologic determinants of marker release from injured myocytes and washout and to take into account the influence of apoptosis. Elucidation and consideration of mechanisms underlying the appearance of specific macromolecular markers in blood appear likely to improve diagnosis and explain the prognostic power of the troponins in patients with unstable angina. Detection of proteolytic breakdown products of troponins in blood is likely to explain the modest, persistent elevations seen in some patients with unstable angina and their prognostic implications
The Chorioallantoic Capillary Plexus of the Chicken Egg: A Microvascular Corrosion Casting Study
The chorioallantoic membrane of the avian egg serves as the principal organ of respiratory gaseous exchange for the embryo until close to hatching. It lies closely apposed to the inner shell membrane and contains an extremely dense capillary plexus supplied by the allantoic blood vessels. This study applied the microvascular corrosion casting technique to investigate the three-dimensional arrangement of the plexus at various stages of incubation. Casts were produced between days 6 and 14 of incubation, and their appearances were compared with those obtained from traditionally sectioned material and from freeze-cleaved specimens.
By day 6 the capillary network was remarkably profuse but showed considerable regional variation in vessel density. In some areas there were only short capillary buds whereas in other areas fusion had taken place so that a true plexus was formed. By day 10 the capillaries had become confluent to such a degree that the cast consisted of a thin sheet of resin perforated only by an array of small irregularly shaped orifices. These corresponded closely in size to the intervening columns of chorionic epithelial cells seen in the sectioned material.
It is clear from the appearances of the casts that the capillary surface density becomes maximal at approximately day 10 of incubation. From then on in incubation any increase in the diffusing capacity of the chorioallantoic membrane must be the result of either an increase in its overall surface area, or a decrease in the thickness of the air-blood barrier
THE DEMOGRAPHICS OF SOFTWARE MAINTENANCE MANAGEMENT
Organizational demographics is proposed as a promising analytic technique for understanding a central problem of information systems (IS) management, the problem of the maintenance of the application system portfolio. This problem is viewed as occurring in significant part as a consequence of the effects and interaction among distributions of individual characteristics of both the application systems and the members of the IS staff. To examine this proposition, a sample of eighteen\u27IS organizations is described in demographic terms, and regression equations are developed to explain variance in maintenance problems associated with the installed portfolios. The results provide support for the proposition, with implications for management and for further research
Synthesis and evaluation of new high temperature polymers for coating applications Technical summary report, 26 Jun. 1964 - 25 Sep. 1966
Synthesis, characterization, and evaluation of organic and semiorganic heat resistant polymer coating
Tropical cyclone and related meteorological data sets available at CSU and their utilization
February, 1982.Includes bibliographical references.This report has been prepared to familiarize the international meteorological community with the comprehensive collection of tropical cyclone and other meteorological data which are available on our research project. We provide a rationale for the research philosophy behind the assembling of these data sets over the last decade, describe the data and indicate how other researchers may use them for their own the research purposes. In particular, we summarize the rawindsonde compositing philosophy and the other research techniques employed on our project. We describe our data processing procedures, the various formulations we have used for different research purposes, the coordinate systems employed and the data availability by region. Our research accomplishments, types of compositing runs, and a list of publications are also presented. These data sets and their software support represent a considerable manpower and financial investment. An investment that is now able (we believe) to provide a high return in the form of new knowledge on tropical cyclones and other weather systems. We are currently exploring a number of exciting avenues. The possibilities are quite broad and we encourage other research workers to help exploit this resource
- …