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.

Tranexamic acid administration practice in otolaryngology head & neck surgery; international survey.

Objectives Various laryngoscopes are currently available for supraglottic, glottic, and cervical esophageal exposure, yet none allow for adjustable articulation of the laryngoscope distal tip. We sought to create a new laryngoscope to improve anatomic field of view exposure. Study design Novel laryngoscope device validation study. Materials and methods Three-dimensional printed plastic and titanium prototype designs were created using Solidworks. Validation testing was performed in a cadaveric model. Optimal exposure of the cadaveric larynx and supraglottis was determined by ensuring the endoscope tip was exactly 2.5 cm from the level of the vocal cords. The prototype exposure (22-cm adjustable tip laryngoscope) was compared to the Weerda (18-cm distending laryngoscope) and Dedo (18-cm operating laryngoscope) laryngoscope exposures. Anteroposterior (AP) and lateral (L) exposure measurements were obtained from analysis of endoscopic images. Objective millimeter quantification was performed by pixel calibration to the known width of the vocal cord. Results The prototype provided 77.3-mm AP and 40.6-mm L exposure of the cadaveric larynx and supraglottis. These measurements were then compared to the exposure provided by the Weerda (49.9-mm AP, 40.4-mm L) and Dedo (15.7-mm AP, 18.6-mm L) laryngoscopes. The investigators found the prototype had similar handling characteristics to the Weerda laryngoscope and laryngeal instrumentation was enhanced due to a wider field of view. Conclusion This novel laryngoscope with an adjustable distal tip provides improved exposure of the supraglottis and glottis in a cadaveric study and has the potential to be used for both supraglottic/glottic and proximal esophageal procedures. Level of evidence 5 Laryngoscope, 2020.

A Novel Laryngoscope With an Adjustable Distal Tip

Low-valent metal-organic frameworks (LVMOFs) and related materials have gained interest due to their potential applications in heterogeneous catalysis.  However, of the rare examples of LVMOFs that have been reported, none have shown catalytic activity.  A low-valent metal-organic material constructed from phosphine linkers and Ir(I) nodes is reported.  This material is effectively a crystalline, insoluble analogue of Vaska's complex.  As such, this material reversibly binds O2 and catalyzes the reductive formation of enamines from amides.

A Coordination Polymer of Vaska's Complex as a Heterogeneous Catalyst for the Reductive Formation of Enamines from Amides.

L'invention concerne des agents de chelation et des chelates metalliques utiles dans des applications diagnostiques ou therapeutiques. Les chelates metalliques de l'invention sont utilises comme milieux de contraste dans des applications d'imagerie medicale, telles que l'imagerie par resonance magnetique (IRM).

Chelateurs multicoordinants derives de pyrone destines a l'imagerie medicale et a la chelation

This cross-sectional study investigates the use of haplotype-based artificial intelligence to identify novel SARS-COV-2 variants and mutations.

https://jamanetwork.com/journals/jamanetworkopen/articlepdf/2801651/zhao_2023_oi_230019_1676274008.43335.pdf

Seth M. Cohen

Papers

Tranexamic acid administration practice in otolaryngology head & neck surgery; international survey.

A Novel Laryngoscope With an Adjustable Distal Tip

A Coordination Polymer of Vaska's Complex as a Heterogeneous Catalyst for the Reductive Formation of Enamines from Amides.

Chelateurs multicoordinants derives de pyrone destines a l'imagerie medicale et a la chelation

Using Haplotype-Based Artificial Intelligence to Evaluate SARS-CoV-2 Novel Variants and Mutations