Substituent effects on the nitrogen-15 and carbon-13 shieldings of some N-arylguanidinium chlorides

The 13C and 15N chemical shifts of five N-arylguanidinium chlorides carrying polar substituents, ranging in character from 4-methoxy to 4-nitro groups, have been determined by NMR spectroscopy at the natural-abundance level of 13C and 15N in dimethyl sulfoxide solution. Comparison of the 13C shifts of these salts with those of monosubstituted benzenes shows that the guanidinium group induces an average downfield shift of -5.8 ppm of the resonance of the aryl carbon to which it is attached (C1), an average upfield shift of +4.2 ppm for C2 and C6, and a small upfield shift of +1.9 ppm for C4. The shifts of C3 and C5 are small and erratic relative to the corresponding carbons in monosubstituted benzenes. The 15N resonances of the guanidinium nitrogens are quite sensitive to electric effects resulting from substitution of polar groups at C4. The 15N shift of the ==NAr nitrogen relative to that of the salts suggests that the predominant tautomer for N-arylguanidines is (H2N)2C==NAr. The 15N shifts of the (NH2) 2 nitrogens correlate rather well with σp- parameters, whereas the shifts of the -NHAr nitrogens seem to correlate only with R values derived from the σp- substituent constants

Carbohydrate intake and cardiometabolic risk factors in high BMI African American children.

The aim of this study was to evaluate the relationship between intakes of subgroups of energy-providing carbohydrate, and markers of cardiometabolic risk factors in high BMI African American (AA) children.A cross sectional analysis was performed on data from a sample of 9-11 year old children (n = 95) with BMI greater than the 85th percentile. Fasting hematological and biochemical values for selected markers of cardiometabolic risk factors were related to intakes of carbohydrates and sugars.After adjusting for gender, pubertal stage and waist circumference, multivariate regression analysis showed that higher intakes of carbohydrate (with fat and protein held constant) were associated with higher plasma concentrations of triglycerides (TG), VLDL-C, IDL-C, and worse insulin resistance (homeostasis model assessment of insulin resistance, HOMA-IR). After dividing carbohydrate into non-sugar versus sugar fractions, sugars were significantly related to higher TG, VLDL-C, IDL-C, lower adipocyte fatty acid insulin sensitivity (ISI-FFA), and was closely associated with increased HOMA-IR. Similar trends were observed for sugars classified as added sugars, and for sugars included in beverages. Further dividing sugar according to the food group from which it was consumed showed that consuming more sugar from the candy/soda food group was highly significantly associated with increased TG, VLDL-C, IDL-C and closely associated with increased HOMA-IR. Sugars consumed in all fruit-containing foods were significantly associated with lower ISI-FFA. Sugars consumed as fruit beverages was significantly associated with VLDL-C, IDL-C and ISI-FFA whereas sugars consumed as fresh, dried and preserved fruits did not show significant associations with these markers.Sugars consumed from in all dairy foods were significantly associated with higher TG, VLDL-C and IDL-C, and with significantly lower HDL-C and ISI-FFA. These effects were associated with sugars consumed in sweetened dairy products, but not with sugars consumed in unsweetened dairy products. This analysis suggests that increases in carbohydrate energy, especially in the form of sugar, may be detrimental to cardiometabolic health in high BMI children

Effect on Constant Versus Fluctuating Temperature Regimes on \u3ci\u3eBathyplectes Curculionis\u3c/i\u3e (Hymenoptera: Ichneumonidae) Activity

Individual female Bathyplectes curculionis parasites were exposed to either a series of constant or fluctuating temperature regimes and supplied with a new group of host Hypera postica larvae every day. The fluctuating temperatures were calculated from an average of weekly air temperatures during a period of actual field oviposition by the parasite. The rearing of adult parasites under a constant versus fluctuating temperature regime resulted in no significant difference in parasitism, longevity, or fecundity. The threshold for B. curculionis activity was estimated to be 6-8°C

Adaptive Group Coordination and Role Differentiation

Many real world situations (potluck dinners, academic departments, sports teams, corporate divisions, committees, seminar classes, etc.) involve actors adjusting their contributions in order to achieve a mutually satisfactory group goal, a win-win result. However, the majority of human group research has involved situations where groups perform poorly because task constraints promote either individual maximization behavior or diffusion of responsibility, and even successful tasks generally involve the propagation of one correct solution through a group. Here we introduce a group task that requires complementary actions among participants in order to reach a shared goal. Without communication, group members submit numbers in an attempt to collectively sum to a randomly selected target number. After receiving group feedback, members adjust their submitted numbers until the target number is reached. For all groups, performance improves with task experience, and group reactivity decreases over rounds. Our empirical results provide evidence for adaptive coordination in human groups, and as the coordination costs increase with group size, large groups adapt through spontaneous role differentiation and self-consistency among members. We suggest several agent-based models with different rules for agent reactions, and we show that the empirical results are best fit by a flexible, adaptive agent strategy in which agents decrease their reactions when the group feedback changes. The task offers a simple experimental platform for studying the general problem of group coordination while maximizing group returns, and we distinguish the task from several games in behavioral game theory

Regulating the Business of Insurance: Federalism in an Age of Difficult Risk

Natural disasters and terrorism events of a massive scale are difficult risks. They are difficult (or, if large enough, impossible) to insure, and they present enormous risk-management challenges. Indeed, we are now in an era when difficult risks are the dominant feature of the risk-management landscape. These kinds of risks are inevitably multi-jurisdictional in nature, and managing them effectively requires a cohesive, comprehensive national catastrophe policy involving ex ante prevention and mitigation measures, effective risk allocation through insurance mechanisms, and ex post victim-compensation strategies. Although our nation is not yet close to establishing a much-needed and increasingly discussed national catastrophe policy, most significant points in current risk management strategies involve significant federal coordination and control. In our judgment, it would be peculiar - and less effective - if ex ante risk-reduction and loss-mitigation strategies and ex post victim compensation programs were the province of the federal government, but risk allocation and distribution decisions that are made in insurance markets were left primarily to the regulatory authority of the states. In other words, we suggest that a regulatory model that defers to the states with respect to the regulation of the insurance aspects of difficult risks is no longer viable, and an enhanced federal role in insurance regulation specifically - and in risk management more generally - is both necessary and appropriate with respect to difficult risks

Regulating the Business of Insurance: Federalism in an Age of Difficult Risk

Although the United States has not established a much-needed and increasingly discussed national catastrophe policy, most significant points in current risk management strategies involve significant federal coordination and control. The authors suggest that a regulatory model that defers to the states with respect to the regulation of the insurance aspects of difficult risks is no longer viable, and an enhanced federal role in insurance regulation specifically -- and in risk management more generally -- is both necessary and appropriate with respect to difficult risks

Regulating the Business of Insurance: Federalism in an Age of Difficult Risk

Although the United States has not established a much-needed and increasingly discussed national catastrophe policy, most significant points in current risk management strategies involve significant federal coordination and control. The authors suggest that a regulatory model that defers to the states with respect to the regulation of the insurance aspects of difficult risks is no longer viable, and an enhanced federal role in insurance regulation specifically -- and in risk management more generally -- is both necessary and appropriate with respect to difficult risks

Ethyl Orthocarbonate [Orthocarbonic acid, tetrahethyl ester]

A solution of sodium ethoxide is prepared under nitrogen from 70 g. (3.04 g. atoms) of sodium and 2 l. of absolute ethanol (Note 1) in a 3-l. three-necked flask which is equipped with mechanical stirrer, efficient reflux condenser, dropping funnel, and a thermometer which dips below the level of the liquid in the flask. Chloropicrin (100 g., 0.61 mole) (Note 2) is placed in the dropping funnel, and the stirred solution is heated to 58–60° with a water bath. The chloropicrin is added at a rate of 30–35 drops per minute until the reaction becomes self-sustaining (about 20 minutes), at which point the water bath is removed and the balance of the chloropicrin is added at a rate sufficient to maintain the temperature at 58–60° (Note 3). When the addition, which requires nearly 2 hours, is complete, the stirrer is stopped and the mixture is allowed to stand overnight

A survey of services for the speech and hearing handicapped in New England

Thesis (Ed. M.)--Boston University, 195

A survey of services for the speech and hearing handicapped in New England

Thesis (Ed. M.)--Boston University, 195