Excess Collateral in the LVTS: How Much is Too Much?

The authors build a theoretical model that generates demand for collateral by Large Value Transfer System (LVTS) participants under the assumption that they minimize the cost of holding and managing collateral for LVTS purposes. The model predicts that the optimal amount of collateral held by each LVTS participant depends on the opportunity cost of collateral, the transactions costs of acquiring assets used as collateral and transferring them in and out of the LVTS, and the distribution of an LVTS participant's payment flows in the LVTS. The authors conclude that the aggregate amount of collateral pledged to the LVTS is quite close to that predicted by the model, when benchmark values are used for opportunity and transactions costs that are based on anecdotal evidence, despite the fact that these costs are likely to vary among participants. If one LVTS participant that appears to face a lower opportunity cost of collateral is excluded from the analysis, the model predicts an aggregate level of collateral that is within 5 per cent of the amount actually held by LVTS participants, on average, between February 1999 and May 2003. The authors also apply panel-data regressions to the level of collateral held in the LVTS. They find that the results are broadly supportive of the theoretical model. Sensitivity analysis of this model indicates that, when the opportunity cost of collateral increases, the amount of collateral that participants hold could be greatly reduced.

The effect of dietary calcium inclusion on broiler gastrointestinal pH: quantification and method optimization

There is little consensus as to the most appropriate methodology for the measurement of gastrointestinal pH in chickens. An experiment was conducted to establish the optimum sampling method for the determination of broiler digesta pH in birds fed differing levels of dietary calcium. Ross 308 broilers (n = 60) were fed one of two experimental diets, one containing 0.8% monocalcium phosphate and 2% limestone and one containing 0.4% monocalcium phosphate and 1% limestone. Four factors were investigated to determine the most appropriate method of measuring broiler gastrointestinal digesta pH: removal from the tract, prolonged air exposure, altering the temperature of the assay, and controlling the water content of the digesta. The conditions were assessed at bird ages from 7 to 42 d post hatch. Dietary Ca content had no significant effect on in situ pH, but it contributed towards variance in ex situ pH of both gizzard and duodenum digesta

Applications of the in vacuo chemical modification technique to the study of protein structure and function.

Sensitive NMR methods have been developed for analyzing N- and C-termini in protein structure for investigating protein purity, identity, and homogeneity. The in vacuo chemical modification procedure allows for the incorporation of isotopically labeled reagents (13C, 14C, 2H, 3H) into protein with a high degree of reaction specificity in a cost-effective manner, since there is no competing reaction with water and only microlitre quantities are required to derivatize milligram quantities of lyophilized protein. Reaction in vacuo at 75°C with 13C-iodomethane results in the preferential 13C-trimethylation of alpha-amino groups in proteins lyophilized from aqueous solutions at pH (LpH) 6 to 7. In vacuo trimethylation of alpha-amino groups and analysis by 13C-NMR spectroscopy provides a new approach for determining the number and types of N-terminal amino acid residues and for verifying the presence of a free or blocked amino-terminus in a protein preparation. Reaction of lyophilized proteins in vacuo at 75°C with 13C-iodomethane at LpH values between 3 and 4 effects the preferential esterification of carboxyl groups, and is in accord with the pH memory effect. The extent of reaction increases with an increase in amount of deprotonated carboxyl groups at higher LpH values, but trimethylation of amino groups is the predominant reaction at LpH values greater than 4 or 5. In contrast, the novel in vacuo esterification reaction (75°C) of lyophilized proteins (LpH 3) with gaseous 13C-methanol/HCl or 13C-ethanol/HCl results in the exclusive, rapid, and extensive formation of alpha-, gamma- and delta-carboxyl 13C-methyl or 13C-ethyl ester derivatives with no protein degradation, which could be distinguished by the distinct chemical shifts of their resonances. Reaction in vacuo with 14C- or 3H-enriched iodomethane results in a higher incorporation of specific radioactivity into lyophilized proteins than can be achieved in aqueous environments. The chemical tag can serve as a probe of structure and function in tracer studies for proteins that are not enzymes. Trace-radiolabeled proteins (e.g., 14C-methylated Bacillus thuringiensis (Bt) insecticidal toxin, 14C-methylated insulin) show a high specific activity, and retain bioactivity (e.g., 14C-methylated Bt toxin). In a separate study, pure bovine and porcine cholesterol esterase (CE) and human milk bile salt-activated lipase are obtained using a cholate-derivatized affinity column and a taurocholate concentration gradient in the eluent, which is critical to the success of the method. Taurocholate induces dimerization of bovine CE in SIDS as observed by SDS-PAGE. Studies of the bile salt-modulated stereoselectivity of CE-catalyzed hydrolysis of alpha-tocopheryl acetates show that, in competitive experiments, the diastereoselectivity of CE depends on the bile salt used, which is relevant if the bile salt-modulated effect on CE-catalyzed reactions is to be exploited in organic syntheses. (Abstract shortened by UMI.

A Comparison of Mainstreamed Traditional Instruction and Pullout Individualized Instruction on Reading Gains of Low-Achievers at Two Junior High Schools

Abstract Not Availabl

Assessment of Growth in Pediatric Syrian Refugee Populations in Jordan

Abstract Background Externally displaced pediatric Syrian refugees are at risk of adverse developmental health outcomes in the setting of food insecurity. To evaluate the impact of displacement on nutritional status of Syrian children, this study describes the prevalence of malnutrition of Syrian children residing in Jordan. Methods A retrospective cross-sectional analysis of data from patient records &lt; 18 years of age from the Syrian American Medical Society's (SAMS) January 2019 mission trip to Jordan was performed. Prevalence of stunting, severe wasting, wasting, overweight, and underweight were calculated using the World Health Organization (WHO) definitions. Results Overall, 392 Syrian children were included. In the 0 to 59 months group (n = 191), prevalence of stunting was 13.9% (n = 165), severe wasting 4.2% (n = 165), wasting 6% (n = 165), overweight 16.4% (n = 165), and underweight 5.3% (n = 190). In the &gt; 59 months group (n = 201), prevalence of stunting was 7.2% (n = 194), severe wasting 3.6% (n = 194), wasting 5.2% (n = 194), overweight 6.7% (n = 194), and underweight 4.6% (n = 153). Age group was significantly associated with stunting (odds ratio [OR]  = 2.08,9 5% CI 1.03 to 4.19) and overweight (OR = 2.72; 95% CI 1.36 to 5.47) with increased odds of each in the 0–59 months group. Conclusion The findings suggest evidence of higher prevalence of malnutrition in Syrian children compared with prior assessments and greater impact on the younger cohort. In 0 to 59 months' old Syrian children, stunting and wasting were of medium severity and overweight was of high severity. This may reflect food insecurity in the setting of ongoing conflict, strain on resources, and evolving refugee policies, acknowledging study limitations. Syrian refugee children living in Jordan experience wasting and stunting. Comprehensive assessment of current nutritional status of Syrian children is needed. Access to adequate and nutritious food is paramount.</jats:p

A simple approach to synthesize and bond organosiloxane films on injection-molded polyolefins

A simple method was devised to fabricate and anchor organosiloxane coatings along low-surface-energy plastics without resorting to chemical pre-treatment of the polymer surface. Polypropylene tubes were purposely distended by exposure to toluene-based solutions. An established solvent of many organic polymers and compounds, toluene not only perfused into the plastic via gradual intercalation of accessible polymer chains, but it also facilitated the entry of less compatible reagents as co-perfusates. The reagents, typically aminoalkyl si lanes, were activated either concomitant to perfitsion of polypro-pylene or during a subsequent hydrolysis step. Freed silanol groups, interacting along and beneath the Surface of the plastic, reacted to form a network held together by siloxane bonds. The type of network formed and presented herein was interpreted as an amorphous aminopropylsiloxane-silanol hydrate film, with overall thickness partially submerged and caught in the matrix of the plastic. This concept to intertwine a growing organosiloxane network and a compliant matrix precluded the conventional methods normally used to improve bonding on hydrophobic plastics. A comparison of ninhydrin color yields suggested that films were more effectively and conveniently synthesized when aminopropyltri-methoxysilane was applied in water-saturated toluene. It follows that by integrating low-temperature hydrothermal processing into this strategy, inorganic-organic hybrids or inorganic oxide films may be formed oil pre-molded plastics and feature traits such as covalent-like fastness and gas impermeability