Health and safety: Preliminary comparative assessment of the Satellite Power System (SPS) and other energy alternatives

Data readily available from the literature were used to make an initial comparison of the health and safety risks of a fission power system with fuel reprocessing; a combined-cycle coal power system with a low-Btu gasifier and open-cycle gas turbine; a central-station, terrestrial, solar photovoltaic power system; the satellite power system; and a first-generation fusion system. The assessment approach consists of the identification of health and safety issues in each phase of the energy cycle from raw material extraction through electrical generation, waste disposal, and system deactivation; quantitative or qualitative evaluation of impact severity; and the rating of each issue with regard to known or potential impact level and level of uncertainty

Comparative health and safety assessment of the SPS and alternative electrical generation systems

A comparative analysis of health and safety risks is presented for the Satellite Power System and five alternative baseload electrical generation systems: a low-Btu coal gasification system with an open-cycle gas turbine combined with a steam topping cycle; a light water fission reactor system without fuel reprocessing; a liquid metal fast breeder fission reactor system; a central station terrestrial photovoltaic system; and a first generation fusion system with magnetic confinement. For comparison, risk from a decentralized roof-top photovoltaic system with battery storage is also evaluated. Quantified estimates of public and occupational risks within ranges of uncertainty were developed for each phase of the energy system. The potential significance of related major health and safety issues that remain unquantitied are also discussed

A TQFT associated to the LMO invariant of three-dimensional manifolds

We construct a Topological Quantum Field Theory (in the sense of Atiyah) associated to the universal finite-type invariant of 3-dimensional manifolds, as a functor from the category of 3-dimensional manifolds with parametrized boundary, satisfying some additional conditions, to an algebraic-combinatorial category. It is built together with its truncations with respect to a natural grading, and we prove that these TQFTs are non-degenerate and anomaly-free. The TQFT(s) induce(s) a (series of) representation(s) of a subgroup ${\cal L}_g$ of the Mapping Class Group that contains the Torelli group. The N=1 truncation produces a TQFT for the Casson-Walker-Lescop invariant.Comment: 28 pages, 13 postscript figures. Version 2 (Section 1 has been considerably shorten, and section 3 has been slightly shorten, since they will constitute a separate paper. Section 4, which contained only announce of results, has been suprimated; it will appear in detail elsewhere. Consequently some statements have been re-numbered. No mathematical changes have been made.

Diassociative algebras and Milnor's invariants for tangles

We extend Milnor's mu-invariants of link homotopy to ordered (classical or virtual) tangles. Simple combinatorial formulas for mu-invariants are given in terms of counting trees in Gauss diagrams. Invariance under Reidemeister moves corresponds to axioms of Loday's diassociative algebra. The relation of tangles to diassociative algebras is formulated in terms of a morphism of corresponding operads.Comment: 17 pages, many figures; v2: several typos correcte

Identification of an Actin-Based Antidiabetic Action of Chromium in Skeletal Muscle

poster abstractWe recently demonstrated that cortical filamentous actin (F-actin) loss contributes to cellular insulin resistance induced by hyperinsulinemia. New animal and human analyses suggest a similar loss of F-actin is present in insulin-resistant skeletal muscle and results from cellular cholesterol accrual. Interestingly, we found that chromium picolinate (CrPic), a dietary supplement recognized to improve insulin action, lowers plasma membrane cholesterol in cultured adipocytes. Understanding whether CrPic can improve F-actin structure in insulinresistant skeletal muscle via lowering membrane cholesterol is not known, yet significant, as skeletal muscle is responsible for a large majority of insulin-stimulated glucose transport. In L6 myotubes stably expressing the insulin-responsive glucose transporter GLUT4 carrying an exofacial myc-epitope tag, acute insulin stimulation (20 min, 100 nM) increased myc-epitope labeling at the surface of intact cells by ~2-fold (P<0.05). In contrast, the ability of insulin to stimulate this process was inhibited 25% (P<0.05) by sustained exposure of L6 myotubes to insulin (12 h, 5 nM). Defects in insulin signaling did not readily account for the observed disruption. However, we found that insulin-induced insulin-resistant myotubes displayed a 28% elevation (P<0.05) in membrane cholesterol with a reciprocal 14% loss (P<0.05) in F-actin. This cholesterol/actin imbalance and insulin/GLUT4 dysfunction was corrected by the cholesterollowering action of CrPic. Mechanistically, CrPic increased the activity of the AMP-activated protein kinase (AMPK). Tests also revealed that other well-recognized activators of AMPK (e.g., AICAR, DNP) lowered membrane cholesterol and that, in a fashion similar to that witnessed for CrPic, improved regulation of GLUT4 in insulin-induced insulin-resistant myotubes. These data, as well as findings from ongoing siRNA-mediated AMPK knockdown experiments, are consistent with AMPK mediating its antidiabetic action by lowering cellular cholesterol. We predict that chromium, via AMPK activation, protects against cholesterol accrual that induces skeletal muscle F-actin loss and insulin resistance

EFFECT OF POLYMORPHISM ON EXPRESSION OF THE NEUROPEPTIDE Y GENE IN INBRED ALCOHOL-PREFERRING AND -NONPREFERRING RATS

Using animal models of alcoholism, previous studies suggest that neuropeptide Y (NPY) may be implicated in alcohol preference and consumption due to its role in the modulation of feeding and anxiety. Quantitative trait loci (QTL) analysis previously identified an interval on rat chromosome 4 that is highly associated with alcohol preference and consumption using an F2 population derived from inbred alcohol-preferring (iP) and -nonpreferring (iNP) rats. NPY mapped to the peak of this QTL region and was prioritized as a candidate gene for alcohol-seeking behavior in the iP and iNP rats. In order to identify a potential mechanism for reduced NPY protein levels documented in the iP rat, genetic and molecular components that influence NPY expression were analyzed between iP and iNP rats. Comparing the iP rat to the iNP rat, quantitative real-time polymerase chain reaction detected significantly decreased levels of NPY mRNA expression in the iP rat in the six brain regions tested: nucleus accumbens, frontal cortex, amygdala, hippocampus, caudate-putamen, and hypothalamus. In addition, the functional significance of three previously identified polymorphisms was assessed using in vitro expression analysis. The polymorphism defined by microsatellite marker D4Mit7 in iP rats reduced luciferase reporter gene expression in SK-N-SH neuroblastoma cells. These results suggest that differential expression of the NPY gene resulting from the D4mit7 marker polymorphism may contribute to reduced levels of NPY in discrete brain regions in the iP rats

Methodology for the comparative assessment of the Satellite Power System (SPS) and alternative technologies

The energy systems concerned are the satellite power system, several coal technologies, geothermal energy, fission, fusion, terrestrial solar systems, and ocean thermal energy conversion. Guidelines are suggested for the characterization of these systems, side-by-side analysis, alternative futures analysis, and integration and aggregation of data. A description of the methods for assessing the technical, economic, environmental, societal, and institutional issues surrounding the development of the selected energy technologies is presented

Chromium Enhances Insulin Responsiveness via AMPK

Trivalent chromium (Cr3+) is known to improve glucose homeostasis. Cr3+ has been shown to improve plasma membrane-based aspects of glucose transporter GLUT4 regulation and increase activity of the cellular energy sensor 5′ AMP-activated protein kinase (AMPK). However, the mechanism(s) by which Cr3+ improves insulin responsiveness and whether AMPK mediates this action is not known. In this study we tested if Cr3+ protected against physiological hyperinsulinemia-induced plasma membrane cholesterol accumulation, cortical filamentous actin (F-actin) loss and insulin resistance in L6 skeletal muscle myotubes. In addition, we performed mechanistic studies to test our hypothesis that AMPK mediates the effects of Cr3+ on GLUT4 and glucose transport regulation. Hyperinsulinemia-induced insulin-resistant L6 myotubes displayed excess membrane cholesterol and diminished cortical F-actin essential for effective glucose transport regulation. These membrane and cytoskeletal abnormalities were associated with defects in insulin-stimulated GLUT4 translocation and glucose transport. Supplementing the culture medium with pharmacologically relevant doses of Cr3+ in the picolinate form (CrPic) protected against membrane cholesterol accumulation, F-actin loss, GLUT4 dysregulation and glucose transport dysfunction. Insulin signaling was neither impaired by hyperinsulinemic conditions nor enhanced by CrPic, whereas CrPic increased AMPK signaling. Mechanistically, siRNA-mediated depletion of AMPK abolished the protective effects of CrPic against GLUT4 and glucose transport dysregulation. Together these findings suggest that the micronutrient Cr3+, via increasing AMPK activity, positively impacts skeletal muscle cell insulin sensitivity and glucose transport regulation

Heights of pre-special points of Shimura varieties

Let s be a special point on a Shimura variety, and x a pre-image of s in a fixed fundamental set of the associated Hermitian symmetric domain. We prove that the height of x is polynomially bounded with respect to the discriminant of the centre of the endomorphism ring of the corresponding ZZ -Hodge structure. Our bound is the final step needed to complete a proof of the André–Oort conjecture under the conjectural lower bounds for the sizes of Galois orbits of special points, using a strategy of Pila and Zannier

Hepatic Glucagon-Receptor Signaling Enhances Insulin-Stimulated Glucose Disposal in Rodents

Glucagon receptor (GCGR) agonists cause hyperglycemia but also weight loss. However, GLP1R/GCGR mixed agonists do not exhibit the diabetogenic effects often attributed to GCGR activity. Thus, we sought to investigate the effect of glucagon agonism on insulin action and glucose homeostasis. Acute GCGR agonism induced immediate hyperglycemia, followed by improved glucose tolerance and enhanced glucose-stimulated insulin secretion. Moreover, acute GCGR agonism improved insulin tolerance in a dose-dependent manner in both lean and obese mice. Improved insulin tolerance was independent of GLP1R, FGF21, and hepatic glycogenolysis. Moreover, we observed increased glucose infusion rate, disposal, uptake, and suppressed endogenous glucose production during euglycemic clamps. Mice treated with insulin and GCGR agonist had enhanced phosphorylation of hepatic AKT at Ser473; this effect was reproduced in isolated mouse primary hepatocytes and resulted in increased AKT kinase activity. These data reveal that GCGR agonism enhances glucose tolerance in part, by augmenting insulin action, with implications for the use of GCGR agonism in therapeutic strategies for diabetes