Photochemical Approaches to Complex Chemotypes: Applications in Natural Product Synthesis.

The use of photochemical transformations is a powerful strategy that allows for the formation of a high degree of molecular complexity from relatively simple building blocks in a single step. A central feature of all light-promoted transformations is the involvement of electronically excited states, generated upon absorption of photons. This produces transient reactive intermediates and significantly alters the reactivity of a chemical compound. The input of energy provided by light thus offers a means to produce strained and unique target compounds that cannot be assembled using thermal protocols. This review aims at highlighting photochemical transformations as a tool for rapidly accessing structurally and stereochemically diverse scaffolds. Synthetic designs based on photochemical transformations have the potential to afford complex polycyclic carbon skeletons with impressive efficiency, which are of high value in total synthesis.R01 GM073855 - NIGMS NIH HHS; R01 GM096129 - NIGMS NIH HHS; R35 GM118173 - NIGMS NIH HH

When one door closes, another door opens: physician availability and motivations to consult complementary and alternative medicine providers.

The aim of this study was to examine the attitudes, behaviours, and intentions to consult complementary and alternative medicine (CAM) providers, of health-care consumers living in a region with low physician availability. A survey was completed by a convenience sample of 235 CAM clients and nonconsumers recruited from an underserved urban centre in Canada. Nearly half had experienced difficulties getting an appointment with a physician when needed, and those who had experienced difficulties were more dissatisfied with conventional health care. Most participants (85.1%) indicated that they would consider consulting a CAM provider should they have difficulty getting an appointment with a physician in the future, including nearly 60% of the CAM nonconsumers. Participants who had more experience with CAM, greater perceived control over their symptoms, and were dissatisfied with conventional health care, were more likely to express intentions to use CAM should they experience access difficulties in the future. By situating the motivations for CAM within the context of physician availability our findings highlight the importance of geographical context, or place, for understanding attitudes towards CAM and its utilisation

Personality and Consultations with Complementary and Alternative Medicine Practitioners: A Five-Factor Model Investigation of the Degree of Use and Motives

Objectives: As interest in and use of complementary and alternative medicine (CAM) providers continues to grow, it is important to understand which characteristics incline people to experiment with and become frequent consumers of CAM practitioners. The purpose of this study was to examine how personality, as assessed by the five-factor model, was related to the breadth, frequency, and types of provider-based CAM use. Relationships between the personality factors (Openness, Conscientiousness, Extraversion, Agreeableness, and Neuroticism) and motives for consulting CAM providers were also explored. Methods: A convenience sample of 184 current CAM clients recruited through the offices of 12 conventional medicine and 17 CAM practitioners completed a survey package including measures of health status, CAM use, personality, and motivations for using CAM. Results: Only Openness and Agreeableness were consistently linked to different dimensions of CAM use, with each associated with consultations with CAM practitioners, and homeopaths and naturopaths in particular. After controlling for sociodemographic and health status variables in the stepwise multiple regressions, Openness was associated with the variety of CAM providers tried, whereas Agreeableness was linked to both the breadth and frequency of CAM consultations. Holistic and proactive health motivations were associated with both personality factors, and Agreeableness was also associated with motives reflecting a desire for shared decision-making. Conclusions: Findings indicate that individuals who are open and agreeable, as described by the five-factor model of personality, consult CAM practitioners to a greater extent. The motives involved suggest a congruency between CAM and their own perspectives regarding health and patient–provider interactions, which may have implications for understanding treatment adherence and outcomes

Consumer decision factors for initial and long-term use of complementary and alternative medicine

Guided by the conceptual framework of the consumer decision-making model, the present study compared the factors associated with initial and long-term use of complementary and alternative medicine (CAM) providers. A survey was completed by 239 people recruited from the offices of physicians and CAM practitioners. Conventional medicine clients (n = 54), new or infrequent clients (n = 73), and established CAM clients (n = 112) were compared to identify the decision factors for initial and long-term CAM use. Consistent with the components of this model, we found support for the roles of external influences (age, social recommendations), decision process factors (symptom severity, egalitarian provider preference), and post-decision factors (dissatisfaction with conventional care) depending on whether the pattern of CAM use was new or infrequent or established. Overall, this study provides preliminary support for the utility of the consumer decision-making model as an integrative framework for understanding the roles of correlates of CAM use. © SAGE Publications, Inc. 2008

Approximation of conformal mappings by circle patterns

A circle pattern is a configuration of circles in the plane whose combinatorics is given by a planar graph G such that to each vertex of G corresponds a circle. If two vertices are connected by an edge in G, the corresponding circles intersect with an intersection angle in $(0,\pi)$. Two sequences of circle patterns are employed to approximate a given conformal map $g$ and its first derivative. For the domain of $g$ we use embedded circle patterns where all circles have the same radius decreasing to 0 and which have uniformly bounded intersection angles. The image circle patterns have the same combinatorics and intersection angles and are determined from boundary conditions (radii or angles) according to the values of $g'$ ($|g'|$ or $\arg g'$). For quasicrystallic circle patterns the convergence result is strengthened to $C^\infty$-convergence on compact subsets.Comment: 36 pages, 7 figure

Search for a T_20 Analyzer for Deuterons

This work was supported by the National Science Foundation Grant NSF PHY 81-14339 and by Indiana Universit

Measurements of d+p Elastic Scattering Analyzing Powers at 80 MeV

This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440

Non-standard Hamiltonian effects on neutrino oscillations

We investigate non-standard Hamiltonian effects on neutrino oscillations, which are effective additional contributions to the vacuum or matter Hamiltonian. Since these effects can enter in either flavor or mass basis, we develop an understanding of the difference between these bases representing the underlying theoretical model. In particular, the simplest of these effects are classified as ``pure'' flavor or mass effects, where the appearance of such a ``pure'' effect can be quite plausible as a leading non-standard contribution from theoretical models. Compared to earlier studies investigating particular effects, we aim for a top-down classification of a possible ``new physics'' signature at future long-baseline neutrino oscillation precision experiments. We develop a general framework for such effects with two neutrino flavors and discuss the extension to three neutrino flavors, as well as we demonstrate the challenges for a neutrino factory to distinguish the theoretical origin of these effects with a numerical example. We find how the precision measurement of neutrino oscillation parameters can be altered by non-standard effects alone (not including non-standard interactions in the creation and detection processes) and that the non-standard effects on Hamiltonian level can be distinguished from other non-standard effects (such as neutrino decoherence and decay) if we consider specific imprint of the effects on the energy spectra of several different oscillation channels at a neutrino factory.Comment: 30 pages, 6 figures, LaTeX, final version, published in Eur.Phys.J.

Spanning forests and the q-state Potts model in the limit q \to 0

We study the q-state Potts model with nearest-neighbor coupling v=e^{\beta J}-1 in the limit q,v \to 0 with the ratio w = v/q held fixed. Combinatorially, this limit gives rise to the generating polynomial of spanning forests; physically, it provides information about the Potts-model phase diagram in the neighborhood of (q,v) = (0,0). We have studied this model on the square and triangular lattices, using a transfer-matrix approach at both real and complex values of w. For both lattices, we have computed the symbolic transfer matrices for cylindrical strips of widths 2 \le L \le 10, as well as the limiting curves of partition-function zeros in the complex w-plane. For real w, we find two distinct phases separated by a transition point w=w_0, where w_0 = -1/4 (resp. w_0 = -0.1753 \pm 0.0002) for the square (resp. triangular) lattice. For w > w_0 we find a non-critical disordered phase, while for w < w_0 our results are compatible with a massless Berker-Kadanoff phase with conformal charge c = -2 and leading thermal scaling dimension x_{T,1} = 2 (marginal operator). At w = w_0 we find a "first-order critical point": the first derivative of the free energy is discontinuous at w_0, while the correlation length diverges as w \downarrow w_0 (and is infinite at w = w_0). The critical behavior at w = w_0 seems to be the same for both lattices and it differs from that of the Berker-Kadanoff phase: our results suggest that the conformal charge is c = -1, the leading thermal scaling dimension is x_{T,1} = 0, and the critical exponents are \nu = 1/d = 1/2 and \alpha = 1.Comment: 131 pages (LaTeX2e). Includes tex file, three sty files, and 65 Postscript figures. Also included are Mathematica files forests_sq_2-9P.m and forests_tri_2-9P.m. Final journal versio

Developing a framework to improve global estimates of conservation area coverage

Area-based conservation is a widely used approach for maintaining biodiversity, and there are ongoing discussions over what is an appropriate global conservation area coverage target. To inform such debates, it is necessary to know the extent and ecological representativeness of the current conservation area network, but this is hampered by gaps in existing global datasets. In particular, although data on privately and community-governed protected areas and other effective area-based conservation measures are often available at the national level, it can take many years to incorporate these into official datasets. This suggests a complementary approach is needed based on selecting a sample of countries and using their national-scale datasets to produce more accurate metrics. However, every country added to the sample increases the costs of data collection, collation and analysis. To address this, here we present a data collection framework underpinned by a spatial prioritization algorithm, which identifies a minimum set of countries that are also representative of 10 factors that influence conservation area establishment and biodiversity patterns. We then illustrate this approach by identifying a representative set of sampling units that cover 10% of the terrestrial realm, which included areas in only 25 countries. In contrast, selecting 10% of the terrestrial realm at random included areas across a mean of 162 countries. These sampling units could be the focus of future data collation on different types of conservation area. Analysing these data could produce more rapid and accurate estimates of global conservation area coverage and ecological representativeness, complementing existing international reporting systems