Two yellow luminescence bands in undoped GaN.

Two yellow luminescence bands related to different defects have been revealed in undoped GaN grown by hydride vapor phase epitaxy (HVPE). One of them, labeled YL1, has the zero-phonon line (ZPL) at 2.57 eV and the band maximum at 2.

On the Possibility of Calculating Entropy, Free Energy, and Enthalpy of Vitreous Substances.

A critical analysis for the arguments in support of, and against, the traditional approach to thermodynamics of vitreous state is provided. In this approach one presumes that there is a continuous variation of the entropy in the glass-liquid transition temperature range, or a "" towards 0 K which produces a positive value of the entropy at → 0 K. I find that arguments given against this traditional approach use a different understanding of the thermodynamics of glass transition on cooling a liquid, because it suggests a discontinuity or "" in the variation of entropy in the glass-liquid transition range.

A Simple 3-Parameter Model for Cancer Incidences.

We propose a simple 3-parameter model that provides very good fits for incidence curves of 18 common solid cancers even when variations due to different locations, races, or periods are taken into account. From a data perspective, we use model selection (Akaike information criterion) to show that this model, which is based on the Weibull distribution, outperforms other simple models like the Gamma distribution. From a modeling perspective, the Weibull distribution can be justified as modeling the accumulation of driver events, which establishes a link to stem cell division based cancer development models and a connection to a recursion formula for intrinsic cancer risk published by Wu et al.

Centralized Networks to Generate Human Body Motions.

We consider continuous-time recurrent neural networks as dynamical models for the simulation of human body motions. These networks consist of a few centers and many satellites connected to them. The centers evolve in time as periodical oscillators with different frequencies.

Socioeconomic characterization of regions through the lens of individual financial transactions.

People are increasingly leaving digital traces of their daily activities through interacting with their digital environment. Among these traces, financial transactions are of paramount interest since they provide a panoramic view of human life through the lens of purchases, from food and clothes to sport and travel. Although many analyses have been done to study the individual preferences based on credit card transaction, characterizing human behavior at larger scales remains largely unexplored.

Molecular mobility in several imidazolium-based ionic liquids according to data of H and C NMR relaxation.

Temperature dependences are compared for H and C NMR 1/T curves relaxation rates in three imidazolium-based ionic liquids (ILs), namely, in [bmim]PF , [bmim]BF , and [emim]CH COO. C curves show alike behavior for all three ILs and follow a well-known Bloembergen-Pound-Purcell (BPP) equation. On the contrary, an essential part of H curves differ strongly from corresponding C ones and also have different shapes for different ILs.

Structure of 311 service requests as a signature of urban location.

While urban systems demonstrate high spatial heterogeneity, many urban planning, economic and political decisions heavily rely on a deep understanding of local neighborhood contexts. We show that the structure of 311 Service Requests enables one possible way of building a unique signature of the local urban context, thus being able to serve as a low-cost decision support tool for urban stakeholders. Considering examples of New York City, Boston and Chicago, we demonstrate how 311 Service Requests recorded and categorized by type in each neighborhood can be utilized to generate a meaningful classification of locations across the city, based on distinctive socioeconomic profiles.

Evaluation of the concentration of point defects in GaN.

Photoluminescence (PL) was used to estimate the concentration of point defects in GaN. The results are compared with data from positron annihilation spectroscopy (PAS), secondary ion mass spectrometry (SIMS), and deep level transient spectroscopy (DLTS). Defect-related PL intensity in undoped GaN grown by hydride vapor phase epitaxy increases linearly with the concentration of related defects only up to 10 cm.

Structural consequences of mutations associated with idiopathic restrictive cardiomyopathy.

Idiopathic restrictive cardiomyopathy (RCM, MIM# 115210) is the least common type of cardiomyopathies, often of genetic origin. Recently we described a spectrum of variants-classified as pathogenic, likely pathogenic and variants of unknown significance-in 24 patients suffering from idiopathic RCM. Pathogenic variants, detected in half of the RCM cases, were found in sarcomeric and cytoskeletal genes that have a predominant role in the development of RCM.

The microbial metabolite desaminotyrosine protects from influenza through type I interferon.

The microbiota is known to modulate the host response to influenza infection through as-yet-unclear mechanisms. We hypothesized that components of the microbiota exert effects through type I interferon (IFN), a hypothesis supported by analysis of influenza in a gain-of-function genetic mouse model. Here we show that a microbially associated metabolite, desaminotyrosine (DAT), protects from influenza through augmentation of type I IFN signaling and diminution of lung immunopathology.

A cell-based mechanical model of coronary artery tunica media.

A three-dimensional cell-based mechanical model of coronary artery tunica media is proposed. The model is composed of spherical cells forming a hexagonal close-packed lattice. Tissue anisotropy is taken into account by varying interaction forces with the direction of intercellular connection.

[Archaic stereotypies and modern approaches for understanding of ageing].

In the article we discussed the processes of awareness of the place of elderly people in modern society, elaboration of adequate relation to global aging and elderly themselves are still going in social sciences. These processes are expressed in a clash of archaic stereotypes and new approaches which changed social and age structure requires. Not only elderly people are providers of archaic stereotypes, but scientific institutions and practices as well.

Modulation of unpolarized light in planar-aligned subwavelength-pitch deformed-helix ferroelectric liquid crystals.

We study the electro-optic properties of subwavelength-pitch deformed-helix ferroelectric liquid crystals (DHFLC) illuminated with unpolarized light. In the experimental setup based on the Mach-Zehnder interferometer, it was observed that the reference and the sample beams being both unpolarized produce the interference pattern which is insensitive to rotation of in-plane optical axes of the DHFLC cell. We find that the field-induced shift of the interference fringes can be described in terms of the electrically dependent Pancharatnam relative phase determined by the averaged phase shift, whereas the visibility of the fringes is solely dictated by the phase retardation.

Biodiversity, extinctions, and evolution of ecosystems with shared resources.

We investigate the formation of stable ecological networks where many species share the same resource. We show that such a stable ecosystem naturally occurs as a result of extinctions. We obtain an analytical relation for the number of coexisting species, and we find a relation describing how many species that may become extinct as a result of a sharp environmental change.

Horizons of cybernetical physics.

The subject and main areas of a new research field-cybernetical physics-are discussed. A brief history of cybernetical physics is outlined. The main areas of activity in cybernetical physics are briefly surveyed, such as control of oscillatory and chaotic behaviour, control of resonance and synchronization, control in thermodynamics, control of distributed systems and networks, quantum control.

Peroxide dental bleaching via laser microchannels and tooth color measurements.

The aim of this study was to use microchannels drilled by an Er:YAG laser into a human tooth through the enamel into the dentin for direct injection of hydrogen peroxide (HP) to produce a minimally invasive, rapid, tooth bleaching effect. The experiments were conducted in vitro. Five microchannels with a diameter of ?200???m and a depth of ?2??mm were drilled through the palatal side of a human tooth crown using the microbeam of an Er:YAG-laser with a wavelength of 2.

Determination of the electron-capture coefficients and the concentration of free electrons in GaN from time-resolved photoluminescence.

Point defects in high-purity GaN layers grown by hydride vapor phase epitaxy are studied by steady-state and time-resolved photoluminescence (PL). The electron-capture coefficients for defects responsible for the dominant defect-related PL bands in this material are found. The capture coefficients for all the defects, except for the green luminescence (GL1) band, are independent of temperature.

Energy surface and minimum energy paths for Fréedericksz transitions in bistable cholesteric liquid crystals.

The multidimensional energy surface of a cholesteric liquid crystal in a planar cell is investigated as a function of spherical coordinates determining the director orientation. Minima on the energy surface correspond to the stable states with particular director distribution. External electric and magnetic fields deform the energy surface and positions of minima.

Hamiltonian dynamics for complex food webs.

We investigate stability and dynamics of large ecological networks by introducing classical methods of dynamical system theory from physics, including Hamiltonian and averaging methods. Our analysis exploits the topological structure of the network, namely the existence of strongly connected nodes (hubs) in the networks. We reveal new relations between topology, interaction structure, and network dynamics.

Light modulation in planar aligned short-pitch deformed-helix ferroelectric liquid crystals.

We study both experimentally and theoretically modulation of light in a planar aligned deformed-helix ferroelectric liquid crystal (DHFLC) cell with subwavelength helix pitch, which is also known as a short-pitch DHFLC. In our experiments, the azimuthal angle of the in-plane optical axis and electrically controlled parts of the principal in-plane refractive indices are measured as a function of voltage applied across the cell. Theoretical results giving the effective optical tensor of a short-pitch DHFLC expressed in terms of the smectic tilt angle and the refractive indices of the ferroelectric liquid crystal (FLC) are used to fit the experimental data.

Scanning thermal microscopy with heat conductive nanowire probes.

Scanning thermal microscopy (SThM), which enables measurement of thermal transport and temperature distribution in devices and materials with nanoscale resolution is rapidly becoming a key approach in resolving heat dissipation problems in modern processors and assisting development of new thermoelectric materials. In SThM, the self-heating thermal sensor contacts the sample allowing studying of the temperature distribution and heat transport in nanoscaled materials and devices. The main factors that limit the resolution and sensitivities of SThM measurements are the low efficiency of thermal coupling and the lateral dimensions of the probed area of the surface studied.

[Low-molecular-weight DNA in blood plasma and cerebrospinal fluid of patients with acute stroke].

Aim: To characterize the value of low-molecular-weight DNA in blood plasma and cerebrospinal fluid for the diagnosis of acute stroke of ischemic and hemorrhagic types early after the onset of the disease.

Material And Methods: DNA from plasma and cerebrospinal fluid was isolated by phenol deproteinization, analyzed by gradient polyacrylamide electrophoresis. Content of low-molecular-weight DNA was determined on the electrophoregram by comparison with standards.

Multi-beam laser-induced hydrodynamic shock waves used for delivery of microparticles and liquids in skin.

Background And Objectives: Laser radiation is often used to provide micro and nanoparticle delivery into the skin for medical and cosmetic purposes. This technique inherently has limited speed and effective penetration. We proposed and investigated a new method of rapid delivery of solid microparticles, nanoparticles and liquids into tissue through multiple microchannels created by a fractional laser microablation (FLMA) using Er:YAG-laser.

The role of markup for enabling interoperability in health informatics.

Interoperability is the faculty of making information systems work together. In this paper we will distinguish a number of different forms that interoperability can take and show how they are realized on a variety of physiological and health care use cases. The last 15 years has seen the rise of very cheap digital storage both on and off site.

Wet spinning of fibers made of chitosan and chitin nanofibrils.

Biocompatible and bioresorbable composite fibers consisting of chitosan filled with anisotropic chitin nanofibrils with the length of 600-800 nm and cross section of about 11-12 nm as revealed by SEM and XRD were prepared by coagulation. Both chitin and chitosan components of the composite fibers displayed preferred orientations. Orientation of chitosan molecules induced by chitin nanocrystallites was confirmed by molecular modeling.