There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Fast parallel algorithms for short-range molecular dynamics

Crystalline metal-organic frameworks (MOFs) are formed by reticular synthesis, which creates strong bonds between inorganic and organic units. Careful selection of MOF constituents can yield crystals of ultrahigh porosity and high thermal and chemical stability. These characteristics allow the interior of MOFs to be chemically altered for use in gas separation, gas storage, and catalysis, among other applications. The precision commonly exercised in their chemical modification and the ability to expand their metrics without changing the underlying topology have not been achieved with other solids. MOFs whose chemical composition and shape of building units can be multiply varied within a particular structure already exist and may lead to materials that offer a synergistic combination of properties.

The Chemistry and Applications of Metal-Organic Frameworks

This paper presents cosmological results based on full-mission Planck observations of temperature and polarization anisotropies of the cosmic microwave background (CMB) radiation. Our results are in very good agreement with the 2013 analysis of the Planck nominal-mission temperature data, but with increased precision. The temperature and polarization power spectra are consistent with the standard spatially-flat 6-parameter ΛCDM cosmology with a power-law spectrum of adiabatic scalar perturbations (denoted “base ΛCDM” in this paper). From the Planck temperature data combined with Planck lensing, for this cosmology we find a Hubble constant, H0 = (67.8 ± 0.9) km s-1Mpc-1, a matter density parameter Ωm = 0.308 ± 0.012, and a tilted scalar spectral index with ns = 0.968 ± 0.006, consistent with the 2013 analysis. Note that in this abstract we quote 68% confidence limits on measured parameters and 95% upper limits on other parameters. We present the first results of polarization measurements with the Low Frequency Instrument at large angular scales. Combined with the Planck temperature and lensing data, these measurements give a reionization optical depth of τ = 0.066 ± 0.016, corresponding to a reionization redshift of . These results are consistent with those from WMAP polarization measurements cleaned for dust emission using 353-GHz polarization maps from the High Frequency Instrument. We find no evidence for any departure from base ΛCDM in the neutrino sector of the theory; for example, combining Planck observations with other astrophysical data we find Neff = 3.15 ± 0.23 for the effective number of relativistic degrees of freedom, consistent with the value Neff = 3.046 of the Standard Model of particle physics. The sum of neutrino masses is constrained to ∑ mν < 0.23 eV. The spatial curvature of our Universe is found to be very close to zero, with | ΩK | < 0.005. Adding a tensor component as a single-parameter extension to base ΛCDM we find an upper limit on the tensor-to-scalar ratio of r0.002< 0.11, consistent with the Planck 2013 results and consistent with the B-mode polarization constraints from a joint analysis of BICEP2, Keck Array, and Planck (BKP) data. Adding the BKP B-mode data to our analysis leads to a tighter constraint of r0.002 < 0.09 and disfavours inflationarymodels with a V(φ) ∝ φ2 potential. The addition of Planck polarization data leads to strong constraints on deviations from a purely adiabatic spectrum of fluctuations. We find no evidence for any contribution from isocurvature perturbations or from cosmic defects. Combining Planck data with other astrophysical data, including Type Ia supernovae, the equation of state of dark energy is constrained to w = −1.006 ± 0.045, consistent with the expected value for a cosmological constant. The standard big bang nucleosynthesis predictions for the helium and deuterium abundances for the best-fit Planck base ΛCDM cosmology are in excellent agreement with observations. We also constraints on annihilating dark matter and on possible deviations from the standard recombination history. In neither case do we find no evidence for new physics. The Planck results for base ΛCDM are in good agreement with baryon acoustic oscillation data and with the JLA sample of Type Ia supernovae. However, as in the 2013 analysis, the amplitude of the fluctuation spectrum is found to be higher than inferred from some analyses of rich cluster counts and weak gravitational lensing. We show that these tensions cannot easily be resolved with simple modifications of the base ΛCDM cosmology. Apart from these tensions, the base ΛCDM cosmology provides an excellent description of the Planck CMB observations and many other astrophysical data sets.

/pdf/planck-2015-results-xiii-cosmological-parameters-5ghxckgd73.pdf

Planck 2015 results - XIII. Cosmological parameters

Background: Thyroid nodules are a common clinical problem, and differentiated thyroid cancer is becoming increasingly prevalent. Since the American Thyroid Association's (ATA's) guidelines for the management of these disorders were revised in 2009, significant scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid nodules and differentiated thyroid cancer. Methods: The specific clinical questions addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of task force members. Task force panel members were educated on knowledge synthesis methods, including electronic database searching, review and selection of relevant citations, and critical appraisal of selected studies. Published English language articles on adults were eligible for inclusion. The American College of Physicians Guideline Gr...

/pdf/2015-american-thyroid-association-management-guidelines-for-32kri8vrhd.pdf

2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer.

La presente invention concerne des inhibiteurs de metalloproteines comprenant: a) une molecule squelette organique (Pep) et au moins un groupe de liaison au zinc (ZBG) relie par covalence a ladite molecule; ou b) au moins un ZBG substitue par une chaine laterale qui comprend un ou plusieurs groupements amino et/ou amido. Le groupe de liaison au zinc est represente par la formule (I): dans laquelle, la ligne ondulee represente une molecule Pep ou une chaine laterale qui represente un groupe R3 ou un groupe R4 qui comprend un ou plusieurs groupements amino et/ou amido, et X represente O ou S et chaque R1, R2, R3, et R4 est, individuellement hydrogene ou un radical organique. Les inhibiteurs de metalloproteines sont utiles pour prevenir ou traiter une maladie pathologique, un etat pathologique ou un symptome qui est associe a l'activite pathologique des metalloproteines et/ou qui est soulage par inhibition de cette activite.

Groupes de liaison au zinc pour inhibiteurs de metalloproteines

A one-pot reaction of maltol with Lawesson's reagent generates dithiomaltol, a thiopyran-4-thione, via an unusual heterocyclic atom exchange (HCAE) reaction; only pyrones with proton or aliphatic substituents undergo the HCAE substitution.

A Novel Heterocyclic Atom Exchange Reaction with Lawesson′s Reagent: A One‐Pot Synthesis of Dithiomaltol.


 This cross-sectional study evaluates the association of sociodemographic characteristics and care utilization with improved voice function among a large sample of older US adults.


Association of Visit Volume and Sociodemographic Characteristics With Vocal Improvement Among Older US Adults With a Self-reported Voice Problem.

The Conflict of Interest statement for this article was incomplete. The statement should read: “S.M.C. is a cofounder of and has an equity interest in Cleave Therapeutics, Forge Therapeutics, and Blacksmith Medicines, companies that may potentially benefit from the research results. S.M.C. also serves on the Scientific Advisory Board for Blacksmith Medicines and serves on the Scientific Advisory Board and receives compensation from Forge Therapeutics. The terms of this arrangement have been reviewed and approved by the University of California, San Diego in accordance with its conflict-of-interest policies.” 

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/cmdc.202200087

Corrigendum: Identification of Adenosine Deaminase Inhibitors by Metal‐binding Pharmacophore Screening

Objective. To identify factors related to the health care spending of patients with laryngeal disorders. Study Design and Setting. Retrospective analysis of data from a large, nationally representative administrative US claims database. Subjects and Methods. Patients with a laryngeal disorder based on International Classification of Diseases, Ninth Revision, Clinical Modification codes from January 1, 2004, to December 31, 2008, and who were continuously enrolled for 12 months were included. Age, sex, comorbidity, geography, provider type, visit type, and type of laryngeal pathology were collected. To identify which factors were related to the direct costs, a generalized linear regression with gamma distribution was used. Results. Of almost 55 million individuals in the database, 309,300 patients with a laryngeal disorder and 12 months of follow-up data were identified (mean (SD) age, 47.3 (21.3) years; 63.5% female). Age, sex, geographic region, number of comorbid conditions, type of provider, visit type, and laryngeal pathology were significantly associated with the health care expenditures (all P values \.05). Costs increased with increas- ing age and were greater for male patients, higher in the South and Northeast compared with the West and North-central regions, greater in 2008 compared with 2004, higher for inpati- ent compared with outpatient care, higher with increasing number of comorbid conditions, and lower if a patient was treated by a primary care physician only. Among the various laryngeal pathologies, the greatest direct costs were for laryn- geal cancer and patients with multiple diagnoses. Conclusion. This study identified multiple factors associated with the health care expenditures of patients with laryngeal disorders.

Seth M. Cohen

Papers

Groupes de liaison au zinc pour inhibiteurs de metalloproteines

A Novel Heterocyclic Atom Exchange Reaction with Lawesson′s Reagent: A One‐Pot Synthesis of Dithiomaltol.

Association of Visit Volume and Sociodemographic Characteristics With Vocal Improvement Among Older US Adults With a Self-reported Voice Problem.

Corrigendum: Identification of Adenosine Deaminase Inhibitors by Metal‐binding Pharmacophore Screening

Factors Influencing the Health Care Expenditures of Patients with Laryngeal