Groups of Fibonacci type revisited

This article concerns a class of groups of Fibonacci type introduced by Johnson and Mawdesley that includes Conway?s Fibonacci groups, the Sieradski groups, and the Gilbert-Howie groups. This class of groups provides an interesting focus for developing the theory of cyclically presented groups and, following questions by Bardakov and Vesnin and by Cavicchioli, Hegenbarth, and Repov?s, they have enjoyed renewed interest in recent years. We survey results concerning their algebraic properties, such as isomorphisms within the class, the classification of the finite groups, small cancellation properties, abelianizations, asphericity, connections with Labelled Oriented Graph groups, and the semigroups of Fibonacci type. Further, we present a new method of proving the classification of the finite groups that deals with all but three groups

Study of Lattice QCD Form Factors Using the Extended Gari-Krumpelmann Model

We explore the suitability of a modern vector meson dominance (VMD) model as a method for chiral extrapolation of nucleon electromagnetic form factor simulations in lattice QCD. It is found that the VMD fits to experimental data can be readily generalized to describe the lattice simulations. However, the converse is not true. That is, the VMD form is unsuitable as a method of extrapolation of lattice simulations at large quark mass to the physical regime.Comment: 14 pages, 5 figure

Comparison of Nucleon Form Factors from Lattice QCD Against the Light Front Cloudy Bag Model and Extrapolation to the Physical Mass Regime

We explore the possibility of extrapolating state of the art lattice QCD calculations of nucleon form factors to the physical regime. We find that the lattice results can be reproduced using the Light Front Cloudy Bag Model by letting its parameters be analytic functions of the quark mass. We then use the model to extend the lattice calculations to large values of Q^{2} of interest to current and planned experiments. These functions are also used to define extrapolations to the physical value of the pion mass, thereby allowing us to study how the predicted zero in G_{E}(Q^{2})/G_{M}(Q^{2}) varies as a function of quark mass.Comment: 31 pages, 22 figure

Constituent description of NN elastic scattering observables at large angles

We suggest that the constituent picture of nucleon-nucleon elastic scattering can be tested by the spin-correlation measurements All, Ass, Ann, and Asl. These measurements provide a means for isolating various reaction mechanisms, including possible quantum-chromodynamic instanton effects. We give specific model calculations to illustrate these ideas

1,3-Allylic Strain as a Strategic Diversification Element For Constructing Libraries of Substituted 2-Arylpiperidines

Flipping diversity—Minimization of 1,3-allylic strain is a recurring element in the design of a stereochemically- and spatially-diverse collection of 2-arylpiperidines. Here, stereochemicallydiverse scaffolding is first constructed using A1,3 strain to guide the regioselective addition of nucleophiles, which serve as handles for further substitution. N-substitution with alkyl and acyl substituents again leverages A1,3 strain to direct each stereoisomer to two different conformer populations, doubling the number of library member

Alcohol-induced decrease in muscle protein synthesis associated with increased binding of mTOR and raptor: Comparable effects in young and mature rats

<p>Abstract</p> <p>Background</p> <p>Acute alcohol (EtOH) intoxication decreases muscle protein synthesis via inhibition of mTOR-dependent translation initiation. However, these studies have been performed in relatively young rapidly growing rats in which muscle protein accretion is more sensitive to growth factor and nutrient stimulation. Furthermore, some in vivo-produced effects of EtOH vary in an age-dependent manner. The hypothesis tested in the present study was that young rats will show a more pronounced decrement in muscle protein synthesis than older mature rats in response to acute EtOH intoxication.</p> <p>Methods</p> <p>Male F344 rats were studied at approximately 3 (young) or 12 (mature) months of age. Young rats were injected intraperitoneally with 75 mmol/kg of EtOH, and mature rats injected with either 75 or 90 mmol/kg EtOH. Time-matched saline-injected control rats were included for both age groups. Gastrocnemius protein synthesis and the activity of the mTOR pathway were assessed 2.5 h after EtOH using [³H]-labeled phenylalanine and the phosphorylation of various protein factors known to regulate peptide-chain initiation.</p> <p>Results</p> <p>Blood alcohol levels (BALs) were lower in mature rats compared to young rats after administration of 75 mmol/kg EtOH (154 ± 23 vs 265 ± 24 mg/dL). However, injection of 90 mmol/kg EtOH in mature rats produced BALs comparable to that of young rats (281 ± 33 mg/dL). EtOH decreased muscle protein synthesis similarly in both young and high-dose EtOH-treated mature rats. The EtOH-induced changes in both groups were associated with a concomitant reduction in 4E-BP1 phosphorylation, and redistribution of eIF4E between the active eIF4E·eIF4G and inactive eIF4E·4EBP1 complex. Moreover, EtOH increased the binding of mTOR with raptor in a manner which appeared to be AMPK- and TSC-independent. In contrast, although muscle protein synthesis was unchanged in mature rats given low-dose EtOH, compared to control values, the phosphorylation of rpS6 and eIF4G was decreased.</p> <p>Conclusion</p> <p>These data indicate that muscle protein synthesis is equally sensitive to the inhibitory effects of EtOH in young rapidly growing rats and older mature rats which are growing more slowly, but that mature rats must be given a relatively larger dose of EtOH to achieve the same BAL. Based on the differential response in mature rats to low- and high-dose EtOH, the decreased protein synthesis was associated with a reduction in mTOR activity which was selectively mediated via a reduction in 4E-BP1 phosphorylation and an increase in mTOR·raptor formation.</p

Medical Assistance in Dying (MAiD): Ethical Considerations for Psychologists

Significant ethical challenges arise when mental health practitioners care for patients who seek to accelerate their own dying for rational medically valid reasons. Current and proposed laws provide for medical assistance in dying (MAiD) in several U.S. jurisdictions, all of Canada, and several other nations. Differing provisions of these laws complicate their utility for some patients who seek aid in dying. Some extant laws include roles that mental health professionals might play in assessing patients’ competence or capacity to consent, mental illness, or other cognitive and behavioral factors. Practitioners who choose to accept roles in the MAiD process must consider and resolve a number of ethical challenges including potential conflicts between and among laws, ethical standards, third-party requests, personal values, and patients’ wishes. These include becoming aware of patients who may wish to act independently to end their lives when MAiD laws might otherwise exclude them. Examples from actual cases and the resultant discussion will form a basis for exploration of the ethical and legal complexities confronted when psychologists become engaged in the process either intentionally or incidentally. The lead article (Koocher) is not intended to comprehensively address MAiD in all of its complexity but rather to trigger a thoughtful discussion among the accompanying commentaries