Lancifodilactone G : insights about an unusually stable enol

From quantum mechanics calculations we confirm that the naturally occurring enol lancifodilactone G is stable over the keto form (by 2.6 kcal/mol in water), the only known stable aliphatic enol (devoid of conjugated or bulky aromatics and lacking a 1,3-diketone structural motif known to stabilize enols). We determine architectural elements responsible for the enol stabilization and find a mechanism for keto-enol conversion in solution. In addition, we correct previously reported computational results that were performed on the misinterpreted structure demonstrating that the enol form of this natural product is more stable than previously thought

Lessons Learned from Efforts at Institutional Change: Case Studies of Six OCEPT Institutions

As one part of a multifaceted evaluation of the Oregon Collaborative for Excellence in the Preparation of Teachers (OCEPT), a case study approach was used to enable a deeper understanding of how a diverse group of six institutions attempted to achieve OCEPT goals and to learn more about factors that facilitated or hindered their efforts. Multiple sources of data were used, with heavy reliance on a series of on-site interviews. The analytical framework included a depth and pervasiveness typology of institutional change and a view of change as encompassing meaning, organization, and effects. While goals and accomplishment levels, as well as the depth and pervasiveness of change. varied across the six institutions, OCEPT-influenced changes most likely to be sustained included: new kinds and levels of faculty collaboration; peer-led teaching and learning approaches, and attention to evidence that these approaches positively affect student course performance; increased faculty awareness of their role in teacher recruitment, with related changes in classroom practices; and, continued strengthening of access to infomiation and academic advising for those preparing to become teachers. These institutions, however, did not make significant progress on one major goal of the project—to increase the numbers of underrepresented groups interested in teaching careers. Change was affected by the compatibility of OCEPT goals with institutional and faculty culture, as well as by local collaborative leadership, the size and complexity of the institution, the presence of boundary spanners, and how OCEPT resources were used

A Singularity-Avoiding Moving Least Squares Scheme for Two Dimensional Unstructured Meshes

Moving least squares interpolation schemes are in widespread use as a tool for numerical analysis on scattered data. In particular, they are often employed when solving partial differential equations on unstructured meshes, which are typically needed when the geometry defining the domain is complex. It is known that such schemes can be singular if the data points in the stencil happen to be in certain special geometric arrangements, however little research has addressed this issue specifically. In this paper, a moving least squares scheme is presented which is an appropriate tool for use when solving partial differential equations in two dimensions, and the precise conditions under which singularities occur are identified. The theory is then applied in the form of a stencil building algorithm which automatically detects singular stencils and corrects them in an efficient manner, while attempting to maintain stencil symmetry as closely as possible. Finally, the scheme is used in a convection-diffusion equation solver, and the results of a number of simulations are presented

Phenotypic divergence along lines of genetic variance

Natural populations inhabiting the same environment often independently evolve the same phenotype. Is this replicated evolution a result of genetic constraints imposed by patterns of genetic covariation? We looked for associations between directions of morphological divergence and the orientation of the genetic variance-covariance matrix (G) by using an experimental system of morphological evolution in two allopatric nonsister species of rainbow fish. Replicate populations of both Melanotaenia eachamensis and Melanotaenia duboulayi have independently adapted to lake versus stream hydrodynamic environments. The major axis of divergence (z) among all eight study populations was closely associated with the direction of greatest genetic variance (g(max)), suggesting directional genetic constraint on evolution. However, the direction of hydrodynamic adaptation was strongly associated with vectors of G describing relatively small proportions of the total genetic variance, and was only weakly associated with g(max). In contrast, divergence between replicate populations within each habitat was approximately proportional to the level of genetic variance, a result consistent with theoretical predictions for neutral phenotypic divergence. Divergence between the two species was also primarily along major eigenvectors of G. Our results therefore suggest that hydrodynamic adaptation in rainbow fish was not directionally constrained by the dominant eigenvector of G. Without partitioning divergence as a consequence of the adaptation of interest (here, hydrodynamic adaptation) from divergence due to other processes, empirical studies are likely to overestimate the potential for the major eigenvectors of G to directionally constrain adaptive evolution

Do physicians examine patients in contact isolation less frequently? A brief report

Background: Patients who are hospitalized and infected with multi drug-resistant bacteria are usually placed in contact isolation, which requires hospital personnel to gown and glove before patient examination. Contact isolation with active culture surveillance appears beneficial in preventing the spread of drug-resistant infections; however, contact isolation may impede the ability to examine patients as a result of the additional effort required to gown and glove. We assessed whether patients who are hospitalized and placed under contact precautions are examined less often by second- and third-year medical residents (ie, senior medical residents), and attending physicians during morning rounds. Method: We conducted a prospective cohort study on the inpatient medical services at 2 university-affiliated medical centers. We directly observed senior medical residents and attending physicians during morning rounds, and recorded the contact precaution status of the patient and whether they were examined by either physician. Results: Of a total of 139 patients, 31 (22%) were in contact isolation. Senior medical residents examined 26 of 31 patients (84%) in contact isolation versus 94 of 108 patients (87%) not in contact isolation (relative risk, 0.96; 95% confidence interval, 0.81-1.14; P = .58). In comparison, attending physicians examined 11 of 31 patients (35%) in contact isolation versus 79 of 108 patients (73%) not in contact isolation (relative risk, 0.49; 95% confidence interval, 0.30-0.79; P \u3c .001). Discussion: Attending physicians are about half as likely to examine patients in contact isolation compared with patients not in contact isolation

Do physicians examine patients in contact isolation less frequently? A brief report

Background: Patients who are hospitalized and infected with multi drug-resistant bacteria are usually placed in contact isolation, which requires hospital personnel to gown and glove before patient examination. Contact isolation with active culture surveillance appears beneficial in preventing the spread of drug-resistant infections; however, contact isolation may impede the ability to examine patients as a result of the additional effort required to gown and glove. We assessed whether patients who are hospitalized and placed under contact precautions are examined less often by second- and third-year medical residents (ie, senior medical residents), and attending physicians during morning rounds. Method: We conducted a prospective cohort study on the inpatient medical services at 2 university-affiliated medical centers. We directly observed senior medical residents and attending physicians during morning rounds, and recorded the contact precaution status of the patient and whether they were examined by either physician. Results: Of a total of 139 patients, 31 (22%) were in contact isolation. Senior medical residents examined 26 of 31 patients (84%) in contact isolation versus 94 of 108 patients (87%) not in contact isolation (relative risk, 0.96; 95% confidence interval, 0.81-1.14; P = .58). In comparison, attending physicians examined 11 of 31 patients (35%) in contact isolation versus 79 of 108 patients (73%) not in contact isolation (relative risk, 0.49; 95% confidence interval, 0.30-0.79; P \u3c .001). Discussion: Attending physicians are about half as likely to examine patients in contact isolation compared with patients not in contact isolation

The importance of a plume of tidally-mixed water to the biological oceanography of the Gulf of Maine

During the warmer months of the year the eastern Gulf of Maine features a plume of cold water which extends from the tidally well-mixed area adjacent to Grand Manan Island at the mouth of the Bay of Fundy southwest along the Maine coast to well beyond Penobscot Bay. Near Grand Manan Island the plume waters are cold (ca. 10°C), nearly vertically isothermal and carry high concentrations of dissolved inorganic nutrients. The analysis of temperature-salinity diagrams and hydrographic vertical section plots indicate that the deeper waters in Jordan Basin, of slope water origin, upwell and contribute a significant fraction of the high nutrient concentrations. The plume waters become increasingly stratified as they flow to the southwest which leads to a phytoplankton bloom downstream. Nitrate concentrations within the euphotic zone of the plume decrease approximately linearly (ca. 194 mg-at NO3-N · m−2) along a distance of about 130 km travelled after its exit from the Grand Manan area (ca 7.5 days transit time). Cross frontal mixing and tidal flushing along the south and north sides of the plume could account for ca. 18% of this decrease. Total chlorophyll concentrations increase nearly linearly with distance along the first 80 km and then decrease in the following 50 km, presumably the result of phytoplankton being grazed by zooplankton which apparently propagate in response to the increasing chlorophyll levels. Over the distance of increasing chlorophyll concentrations (80 km) the nitrate decrease, corrected for physical losses laterally, would support a new . primary production of 1.46 gm C m−2 d−1. Our analyses suggest that as much as 44% of the new nitrate which enters the Gulf of Maine at depth through the Northeast Channel upwells in the eastern Gulf becoming part of the plume, and hence this feature appears to be very important to the nutrient budget and general biological oceanography of the inner Gulf of Maine

Microwave Assisted Synthesis of Py-Im Polyamides

Microwave synthesis was utilized to rapidly build Py-Im polyamides in high yields and purity using Boc-protection chemistry on Kaiser oxime resin. A representative polyamide targeting the 5′-WGWWCW-3′ (W = A or T) subset of the consensus Androgen and Glucocorticoid Response Elements was synthesized in 56% yield after 20 linear steps and HPLC purification. It was confirmed by Mosher amide derivatization of the polyamide that a chiral α-amino acid does not racemize after several additional coupling steps

Melting of Partially Fluorinated Graphene: From Detachment of Fluorine Atoms to Large Defects and Random Coils

The melting of fluorographene is very unusual and depends strongly on the degree of fluorination. For temperatures below 1000 K, fully fluorinated graphene (FFG) is thermo-mechanically more stable than graphene but at T$_m\approx$2800 K FFG transits to random coils which is almost twice lower than the melting temperature of graphene, i.e. 5300 K. For fluorinated graphene (PFG) up to 30 % ripples causes detachment of individual F-atoms around 2000 K while for 40-60 % fluorination, large defects are formed beyond 1500 K and beyond 60% of fluorination F-atoms remain bonded to graphene until melting. The results agree with recent experiments on the dependence of the reversibility of the fluorination process on the percentage of fluorination.Comment: 16 pages, 6 figure

Directory to the Floodplain Information Repository - Vol. 1

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