Magnetic fields

Effects of high and low gradient magnetic fields on human performance for space flight application

Ultrasound Guided Placement of Single-Lumen Peripheral Intravenous Catheters in the Internal Jugular Vein

Introduction: The peripheral internal jugular (IJ), also called the “easy IJ,” is an alternative to peripheral venous access reserved for patients with difficult intravenous (IV) access. The procedure involves placing a single-lumen catheter in the IJ vein under ultrasound (US) guidance. As this technique is relatively new, the details regarding the ease of the procedure, how exactly it should be performed, and the safety of the procedure are uncertain. Our primary objective was to determine the success rate for peripheral IJ placement. Secondarily, we evaluated the time needed to complete the procedure and assessed for complications. Methods: This was a prospective, single-center study of US-guided peripheral IJ placement using a 2.5-inch, 18-gauge catheter on a convenience sample of patients with at least two unsuccessful attempts at peripheral IV placement by nursing staff. Peripheral IJ lines were placed by emergency medicine (EM) attending physicians and EM residents who had completed at least five IJ central lines. All physicians who placed lines for the study watched a 15-minute lecture about peripheral IJ technique. A research assistant monitored each line to assess for complications until the patient was discharged. Results: We successfully placed a peripheral IJ in 34 of 35 enrolled patients (97.1%). The median number of attempts required for successful cannulation was one (interquartile range (IQR): 1 to 2). The median time to successful line placement was 3 minutes and 6 seconds (IQR: 59 seconds to 4 minutes and 14 seconds). Two lines failed after placement, and one of the 34 successfully placed peripheral IJ lines (2.9%) had a complication – a local hematoma. There were, however, no arterial punctures or pneumothoraces. Although only eight of 34 lines were placed using sterile attire, there were no line infections. Conclusion: Our research adds to the growing body of evidence supporting US-guided peripheral internal jugular access as a safe and convenient procedure alternative for patients who have difficult IV access

Factors Affecting Lot Low Choice and Above and Lot Premium Choice Acceptance Rate of Beef Calves in the Tri-County Steer Carcass Futurity Program

Data describing 220 lots of beef cattle in the Tri-County Steer Carcass Futurity program from 2003 through 2007 were analyzed using a multiple regression statistical model to determine specific factors that influence lot low Choice and above rate and lot premium Choice (Certified Angus Beef © ) acceptance rate. Lot low Choice and above rate was similar for years 2005-2007. This rate was significantly lower in 2003 than 2004 but both the 2003 and 2004 rates were similar to the rate in all other years. Lots consisting of heifers had higher (P\u3c.05) low Choice and above rates than lots of steers or mixed-sex pens. The greater the amount of Angus influence in the cattle, the higher the low Choice and above rate (P\u3c.0001). An inverse relationship existed between feedlot in-weight and lot low Choice and above rate; those cattle with lighter feedlot arrival weights had higher % Choice and above rates (P=.0007). Cattle with lower disposition scores (calmer cattle) had higher % Choice and above rates (P=.0496). Low Choice and above rate increased as cattle became less efficient in converting feed to gain (P=.0027). An inverse relationship existed between cost of gain and low Choice and above rate; those cattle with lower cost of gain had higher low Choice and above rates (P=.0043). Lot low Choice and above rate increased as average daily gain increased (P=.0094). Factors examined that did not have a significant effect on lot low Choice and above rate were: mud score at final sort, geographic region of origin, lot mortality rate, number of harvest groups within each lot, days on feed, adjusted final weight, individual treatment cost per head, lot size, and season of harvest. Lot premium Choice acceptance rate was similar in each year from 2003-2006 but was significantly lower in 2007 compared with all other years. Lots consisting of heifers had higher (P\u3c.05) premium Choice acceptance rates than lots of steers or mixed-sex pens. Cattle harvested during the months October through December had a lower lot premium Choice acceptance rate than those harvested during January through March, April through June, or July through September (P\u3c.05). The greater the amount of Angus influence in the cattle, the higher the lot premium Choice acceptance rate (P\u3c.0064). An inverse relationship existed between feedlot in-weight and lot premium Choice acceptance rate; those cattle with lighter feedlot arrival weights had higher premium Choice acceptance rates (P\u3c.0001). Lot premium Choice acceptance rate increased as average daily gain increased (P=.0003); however lots of cattle that were less efficient at converting feed into gain had higher premium Choice acceptance rates (P\u3c.0104). Factors examined that did not have a significant effect on lot premium Choice acceptance rate were: mud score at final sort, individual treatment cost per head, number of harvest groups within each lot, days on feed, cost of gain, lot size, geographic region of origin, average disposition score, adjusted final weight, and lot mortality rate

Forest Response to Chronic Hurricane Disturbance in Coastal New England

Question: Hurricanes and cyclones cause a wide range of damage to coastal forests worldwide. Most of these storms are not catastrophic in ecological terms, but forest responses to storms of moderate intensities are poorly understood. In regions with a high frequency of moderate hurricanes, how does variation in disturbance intensity affect the magnitude of ecological responses? Location: Naushon Island, Massachusetts USA Methods: We use historical records and dendroecological methods to characterize establishment and growth of Fagus grandifolia, Quercus alba and Quercus velutina in response to seven non-catastrophic hurricanes of varying intensity and a major logging event, relative to baseline conditions, over the past ~ 150 years. Our aim was to document variation in the magnitude of responses to known disturbance events of varying intensity, and to determine whether tree growth after moderate hurricanes differs from growth during periods of no disturbance. Results: Forest harvesting in 1824-1827 had a strong impact on forest composition and growth. Since then, the study region has been characterized by little harvesting but frequent hurricanes. However, only one of the seven storms examined caused substantial increases in growth and new establishment for the dominant species; most moderate disturbances had minimal impacts on growth and regeneration dynamics. We also document highly variable responses among species to individual storms, including substantial growth decreases that may not be detected by standard analytical approaches. Conclusions: Our results caution against the use of simple metrics such as wind speed to predict forest response to specific hurricanes, and highlight the importance of individual disturbance events in controlling long-term forest dynamics, even in regions characterized by high disturbance frequency. Additionally, we show that standard approaches to reconstructing disturbance history based on increases in radial growth and pulses of tree establishment are likely to underestimate the frequency of moderate disturbances.Other Research Uni

Covariance systems

We introduce new definitions of states and of representations of covariance systems. The GNS-construction is generalized to this context. It associates a representation with each state of the covariance system. Next, states are extended to states of an appropriate covariance algebra. Two applications are given. We describe a nonrelativistic quantum particle, and we give a simple description of the quantum spacetime model introduced by Doplicher et al.Comment: latex with ams-latex, 23 page

Regulating working families in the European Union: a history of disjointed strategies

Families in market economies worldwide have long been confronted with the demands of participating in paid work and providing care for their dependent members. The social, economic and political contexts within which families do so differ from country to country but an increasing number of governments are being asked to engage, or better engage, with this important area of public policy. What seems like a relatively simple goal – to enable families to better balance care-giving and paid employment – has raised several difficulties and dilemmas for policy makers which have been approached in different ways. This paper aims to identify and critique the nature and development of the means by which legal engagement with work-family reconciliation has, historically, been framed in the European Union. In doing so, and with reference to specific cohorts of workers, we demonstrate how disjointed the strategies are in relation to working carers and argue that the EU is unlikely to provide the legal framework necessary to bring about effective change in this fundamentally important area of social policy

Proteolytic cleavage of insulin-like growth factor binding protein 4 (IGFBP-4). Localization of cleavage site to non-homologous region of native IGFBP-4

Insulin-like growth factor binding protein 4 (IGFBP-4) is a 24-kDa protein that binds insulin-like growth factor 1 (IGF-1) and IGF-2 with high affinity and inhibits IGF action in vitro. We recently described a protease produced by the B104 neuronal cell line that cleaves IGFBP-4, yielding an approximate 16-kDa immunoreactive protein that binds IGFs with reduced affinity. We analyzed fragments produced by exposing pure IGFBP-4 to the protease to determine potential cleavage sites. Electrospray mass spectrometry and amino acid sequencing indicated the 16-kDa fragment spanned the NH2 terminus of native IGFBP-4 through Lys-120. There was evidence for an additional proteolytic fragment beginning at amino acid 132 and continuing to the COOH terminus. Proteolysis could be blocked by a synthetic peptide that spanned amino acids 117-126 but not by peptides that contained flanking sequences 111-120 or 125-135. Mutagenesis was used to alter the basic residue at position 120. The expressed mutant IGFBP-4 (K120A) was relatively resistant to cleavage, strongly suggesting that residues 120-121 represent the cleavage site. This region of IGFBP-4 is not homologous with other IGFBPs, explaining the apparent specificity of the protease for IGFBP-4. The 16-kDa IGFBP-4 fragment no longer inhibited IGF-1-stimulated thymidine uptake in vitro, suggesting that proteolytic processing of IGFBP-4 may have important functional consequences in vivo