Early post parturient changes in milk acute phase proteins

The periparturient period is one of the most critical periods in the productive life of a dairy cow, and is the period when dairy cows are most susceptible to developing new intramammary infections (IMI) leading to mastitis. Acute phase proteins (APP) such as haptoglobin (Hp), mammary associated serum amyloid A3 (M-SAA3) and C-reactive protein (CRP) have been detected in milk during mastitis but their presence in colostrum and milk in the immediate postpartum period has had limited investigation. The hypothesis was tested that APP are a constituent of colostrum and milk during this period. Enzyme linked immunosorbent assays (ELISAs) were used to determine each APP’s concentration in colostrum and milk collected daily from the first to tenth day following calving in 22 Holstein-Friesian dairy cows. Haptoglobin was assessed in individual quarters and composite milk samples while M-SAA3 and CRP concentration were determined in composite milk samples. Change in Hp in relation to the high abundance proteins during the transition from colostrum to milk were evaluated by 1 and 2 dimension electrophoresis and western blot. In 80% of the cows all APPs were detected in colostrum on the first day following parturition at moderately high levels but gradually decreased to minimal values in the milk by the 6th day after calving. The remaining cows (20%) showed different patterns in the daily milk APP concentrations and when an elevated level is detected could reflect the presence of IMI. Demonstration that APP are present in colostrum and milk following parturition but fall to low levels within 4 days means that elevated APP after this time could be biomarkers of post parturient mastitis allowing early intervention to reduce disease on dairy farms

Could There Be A Hole In Type Ia Supernovae?

In the favored progenitor scenario, Type Ia supernovae arise from a white dwarf accreting material from a non-degenerate companion star. Soon after the white dwarf explodes, the ejected supernova material engulfs the companion star; two-dimensional hydrodynamical simulations by Marietta et. al. show that, in the interaction, the companion star carves out a conical hole of opening angle 30-40 degrees in the supernova ejecta. In this paper we use multi-dimensional Monte Carlo radiative transfer calculations to explore the observable consequences of an ejecta-hole asymmetry. We calculate the variation of the spectrum, luminosity, and polarization with viewing angle for the aspherical supernova near maximum light. We find that the supernova looks normal from almost all viewing angles except when one looks almost directly down the hole. In the latter case, one sees into the deeper, hotter layers of ejecta. The supernova is relatively brighter and has a peculiar spectrum characterized by more highly ionized species, weaker absorption features, and lower absorption velocities. The spectrum viewed down the hole is comparable to the class of SN 1991T-like supernovae. We consider how the ejecta-hole asymmetry may explain the current spectropolarimetric observations of SNe Ia, and suggest a few observational signatures of the geometry. Finally, we discuss the variety currently seen in observed SNe Ia and how an ejecta-hole asymmetry may fit in as one of several possible sources of diversity.Comment: 11 pages, 9 figures, submitted to Ap

HoPP: Robust and Resilient Publish-Subscribe for an Information-Centric Internet of Things

This paper revisits NDN deployment in the IoT with a special focus on the interaction of sensors and actuators. Such scenarios require high responsiveness and limited control state at the constrained nodes. We argue that the NDN request-response pattern which prevents data push is vital for IoT networks. We contribute HoP-and-Pull (HoPP), a robust publish-subscribe scheme for typical IoT scenarios that targets IoT networks consisting of hundreds of resource constrained devices at intermittent connectivity. Our approach limits the FIB tables to a minimum and naturally supports mobility, temporary network partitioning, data aggregation and near real-time reactivity. We experimentally evaluate the protocol in a real-world deployment using the IoT-Lab testbed with varying numbers of constrained devices, each wirelessly interconnected via IEEE 802.15.4 LowPANs. Implementations are built on CCN-lite with RIOT and support experiments using various single- and multi-hop scenarios

South Carolina Slave Prices, 1722-1809

Based on data from several samples of probate inventories we construct and analyze a time series of slave prices for South Carolina from 1722 to 1809. These estimates reveal that prices fluctuated without trend prior to the 1760s and then began to rise rapidly, more than doubling by the early nineteenth century. Estimates of supply and demand functions indicate that while long-run slave supply was highly elastic, the short-run supply function was quite inelastic. Our analysis of the slave price series indicates that the price of rice was the major determinant of the demand for slaves and in turn largely explains the rise in slave prices. These findings have important implications for the interpretation of evidence on rising yields in rice production over the eighteenth century and the sources of wealth accumulation in South Carolina.

The Rapid Rise of Supermarkets in Developing Countries: Induced Organizational, Institutional, and Technological Change in Agrifood Systems

There has been extremely rapid transformation of the food retail sector in developing regions in the past 5 to 10 years, accompanied by a further consolidation and multi-nationalization of the supermarket sector itself. This organizational change, accompanied by intense competition, has driven changes in the organization of procurement systems of supermarket chains, toward centralized and regionalized systems, use of specialized/dedicated wholesalers and preferred supplier systems, and demanding, private quality standards. These changes in the system have in turn determined the very recent rise of the use of contracts between supermarkets and agrifood producers in these regions to cover provision of services and provision for risk management, as well as requirements for demanding quality and safety attributes, which require substantial investment in technological change and upgrading at the producer level. This paper presents a brief discussion of these trends, followed by a conceptual framework to explain this phenomenon, illustrated with empirical evidence drawn mainly from Latin America.supermarket chains, procurement systems, quality standards, agrifood producers, Agribusiness,

Conjectural Estimates of Economic Growth in the Lower South, 1720 to 1800

This paper describes the first step in a larger project to build up regional estimates of economic growth before 1800 in the parts of North America that became the United States. In it we employ the method of conjectural estimation to develop new estimates of the rate of economic growth in the Lower South (modern day North Carolina, South Carolina, Georgia, and Tennessee) from 1720 to 1800 for both colonists and the Native American population of the region. Contrary to the widely held view that GDP per capita grew at a rate of 0.3 to 0.6 percent per year during the eighteenth century our best estimate is that per capita GDP grew at just 0.09 percent per year. Despite the slow growth of GDP per capita, however, the region's economy did achieve appreciable extensive growth, and achieving any advance in per capita production can be viewed as a significant accomplishment in light of the challenges that this growth posed for the economy. The difference between our estimate and those of previous studies appears to be the result of earlier scholars' undue focus on export performance. In contrast, our approach allows us to accurately account for the effect of the slowly growing domestic sector of the economy.

The Role of Exports in the Economy of Colonial North America: New Estimates for the Middle Colonies

Economic historians of the eighteenth-century British mainland North American colonies have given considerable weight to the role of exports as a stimulus for economic growth. Yet their analyses have been handicapped by reliance on one or two time series to serve as indicators of broader changes rather than considering the export sector as a whole. Here we construct comprehensive export measures for the middle colonies. We find that aggregate exports did grow quickly but that this expansion failed to keep pace with population growth during much of the period under consideration. We argue this result challenges the export staples model on the role of foreign demand as a stimulus for economic growth. Instead, these results emphasize the impact of resource abundance and labor and capital scarcity as the defining characteristics of colonial economic growth.