Crystal and Electronic Structure of High-Temperature Superconductive Layered Cuprates in Temperature Interval 100–300 K

For two HTSC materials, Y_1?x Ca _x Ba₂Cu₃ O _6.7 and Tl_0.8Hg_0.2Ba₂Ca₂Cu₃ O _8.15, their crystal structure has been studied earlier in the temperature interval 100–300 K. It is shown that for both compounds, the height of CuO₅ pyramids has a minimum in temperature interval from ～ 150 to ～ 250 K. The electronic structure is calculated using first principles based on the obtained data of crystal structure. It is revealed that a decrease in the CuO₅ pyramid height leads to the appearance of the electronic state density peak with an energy of 0.3–0.4 eV under Fermi level. Localized states of barium and apical oxygen make the main contribution to this peak. By reduction the temperature below ～ 150 K, these localized electronic states disappear, and under continuous cooling, the superconductivity appears.     

Policy-Induced Environmental Technology and Inventive Efforts: Is There a Crowding Out?

Substantial policy effort is devoted to stimulate environmentally friendly technology through regulation and subsidies. Since innovation is a crucial productivity driver, a potential crowding out of inventive efforts in affected firms may increase the cost of regulation. We study the effects of regulation-induced environmental technology on innovation activities for a sample of firms in Germany. We find some evidence for a crowding out of firms' in-house R&D, especially for firms facing financing constraints. Innovation outcomes and investments in innovation-related fixed assets are not affected. Moreover, subsidy-backed environmental technology does not crowd out R&D.     

Thermal Conductivity of a Three‐Dimensional Body with a Rough Inclusion

Thermal conductivity of a threedimensional body with a rough inclusion is studied. The problem is reduced to the problem of conjugation of harmonic functions and its exact solution is constructed. Distributions of temperature and heatflux density near distinctions of the interface between media are found. Results are illustrated by a numerical example.     

Is unilateral breast enlargement always a sign of cancer?

Breast swelling is caused by many etiological factors, but should alert central vein occlusion in hemodialysis patients when the permanent vascular access is in the same arm. The swelling of the breast is caused by venous hypertension in the venous plexus draining the breast. Endovascular treatment relieves venous hypertension and related clinical signs. Additional diagnostic workup or invasive interventions such as a biopsy should be avoided in such patients, as diagnosis is straightforward with the presence of a functioning arteriovenous fistula in the same arm.     

Pruritus: Is there a grain of salty truth?

Hemodialysis patients characteristically suffer from a range of unpleasant symptoms. Uremic pruritus effects close to half of the chronic kidney disease population, reducing quality of life and associated with increased mortality. Its pathophysiology though is poorly understood; currently deployed therapeutic approaches are ineffective. Excessive levels of skin and soft tissue sodium accumulate in dialysis patients, producing a range of biological consequences, including inflammation. We report an index case of a hemodialysis patient with debilitating pruritus and extreme levels of tissue sodium, measured with Sodium-23 magnetic resonance imaging. Both the tissue sodium loading and pruritus responded fully to initiation of expanded hemodialysis therapy with a recently introduced medium cutoff dialysis membrane-based dialyzer.     

Is a Gas of Strongly Interacting Atomic Fermions a Nearly Perfect Fluid?

We use all-optical methods to produce a highly-degenerate Fermi gas of spin-1/2 ⁶Li atoms. A magnetic field tunes the gas near a collisional (Feshbach) resonance, producing strong interactions between spin-up and spin-down atoms. We have measured properties of a breathing mode over a wide range of temperatures. As the temperature is increased from below the superfluid transition to above, the frequency of the mode is always close to the hydrodynamic value, while the damping rate increases. A complete explanation of both the frequency and the damping rate in the normal collisional regime has not been achieved. Our measurements of the damping rate as a function of the energy of the gas are used to estimate an upper bound on the viscosity. Using our new measurements of the entropy of the gas, we estimate the ratio of the shear viscosity to the entropy density and compare the result with a recent string theory conjecture for the minimum viscosity of a perfect quantum fluid.      

Is 3D Printing of Pharmaceuticals a Disruptor or Enabler?

Additive manufacturing (AM) is a fast‐growing manufacturing approach that comes with the promise of delivering personalized medicine to treat individual patients. However, large‐scale commercial applications in the pharmaceutical industry have been limited. Here, some of the challenges are discussed along with some pharmaceutical products where AM has the potential to make a tangible impact and pave the way for more rapid adoption are highlighted.     

Is the Tendency to Variation a Chief Cause of Progress?

This paper briefly reviews the sources of the diversity of innovativeactivity within industries, and interprets the literature tosuggest that there are three ways in which such diversity maystimulate technological progress, including a selection effect,a breadth effect and a complementarity effect. Using industry-leveldata from the Yale survey administered in the 1980s, the paperpresents preliminary empirical results on the relationship betweenthe diversity of R&D activities within industries and theirrate of technical advance. This exploratory exercise finds that,controlling for industry R&D intensity, greater diversityin innovative activity is associated with a more rapid paceof technological change. Policy implications are considered.     

Is there a thickness effect on compressive strength of unnotched composite laminates?

The effect of laminate thickness was investigated on the compressive behavior of unidirectional and crossply composites. A recently developed compression test method for thick composites was used to test specimens from 16 to 200-plies thick. In all cases the stress-strain behavior to failure is nonlinear and failure strength is matrix dominated. Longitudinal compressive failure is triggered by matrix failure accompanied by fiber microbuckling and the compressive strength is greatly degraded by initial fiber misalignment. The longitudinal compressive strength shows a mild trend of decreasing values with increasing thickness. It can be explained that, even if such a trend is significant, increasing size would have a diminishing effect on compressive strength for initial fiber misalignments greater than 1.5 to 2°. This revised version was published online in July 2006 with corrections to the Cover Date.     

Is hepcidin‐25 a predictor of atherosclerosis in hemodialysis patients?

Atherosclerotic cardiovascular disease is an important cause of mortality and morbidity in hemodialysis patients. Iron accumulation in arterial wall macrophages is increased in atherosclerotic lesions. Hepcidin is a key hepatic hormone regulating iron balance. It inhibits iron release from macrophages and iron absorption from enterocytes by binding and inactivating the cellular iron exporter ferroportin. The aim of this study is to investigate the relation of hepcidin‐25, iron parameters, and atherosclerosis measured by carotid intima media thickness (CIMT) in hemodialysis patients. Eighty‐two hemodialysis patients were enrolled in this cross‐sectional study. Predialysis blood samples were centrifuged at 1500 g and 4°C for 10 minutes and stored at ?80°C for the measurement of hepcidin‐25. DRG hepcidin enzyme‐linked immunosorbent assay kit was used for the measurement of hepcidin‐25. Ultrasonographical B‐mode imaging of bilateral carotid arteries was performed with a high‐resolution real‐time ultrasonography (Mindray DC7). Mean age of the study population was 57.90 ± 16.08 years and 43.9% were men. Total study population was grouped into two according to median value of hepcidin‐25. There was no difference between groups with respect to age, dialysis vintage, and C‐reactive protein. CIMT was found to be statistically significantly higher in low hepcidin‐25 group. In correlation analysis, CIMT was found to be correlated with age (P < 0.01, R = 0.33) and hepcidin‐25 (P < 0.01, R = 0.46). In linear regression analysis, age (β = 0.31) and hepcidin‐25 (β = 0.44) were found to be the determinants of CIMT in hemodialysis patients. Our results implicate that hepcidin may take part in pathophysiology of atherosclerosis and cardiovascular disease in hemodialysis patients.     

Is innovation design- or technology-driven? Citation as a measure of innovation pollination

The present study suggests a cross-citation measure comprised of design and utility patents and proposes a model of innovation pollination. The case of Dyson Ltd. provides empirical evidence of how a design-led, a technology-led, or a cross-pollinating innovation can function in the product innovation. Our findings reveal that the evolution of innovation pollination has distinguishing features according to the product category and the function of the company's prior innovation experience. Dyson's renowned bladeless fans and its bagless vacuum cleaners have been strongly driven by design and technology innovation, such cross-pollination is infrequent. We further discuss the implications technology, design, and innovation management strategy.     

Is the proton radius a player in the redefinition of the International System of Units?

It is now recognized that the International System of Units (SI units) will be redefined in terms of fundamental constants, even if the date when this will occur is still under debate. Actually, the best estimate of fundamental constant values is given by a least-squares adjustment, carried out under the auspices of the Committee on Data for Science and Technology (CODATA) Task Group on Fundamental Constants. This adjustment provides a significant measure of the correctness and overall consistency of the basic theories and experimental methods of physics using the values of the constants obtained from widely differing experiments. The physical theories that underlie this adjustment are assumed to be valid, such as quantum electrodynamics (QED). Testing QED, one of the most precise theories is the aim of many accurate experiments. The calculations and the corresponding experiments can be carried out either on a boundless system, such as the electron magnetic moment anomaly, or on a bound system, such as atomic hydrogen. The value of fundamental constants can be deduced from the comparison of theory and experiment. For example, using QED calculations, the value of the fine structure constant given by the CODATA is mainly inferred from the measurement of the electron magnetic moment anomaly carried out by Gabrielse's group. (Hanneke et al. 2008 Phys. Rev. Lett. 100, 120801) The value of the Rydberg constant is known from two-photon spectroscopy of hydrogen combined with accurate theoretical quantities. The Rydberg constant, determined by the comparison of theory and experiment using atomic hydrogen, is known with a relative uncertainty of 6.6×10(-12). It is one of the most accurate fundamental constants to date. A careful analysis shows that knowledge of the electrical size of the proton is nowadays a limitation in this comparison. The aim of muonic hydrogen spectroscopy was to obtain an accurate value of the proton charge radius. However, the value deduced from this experiment contradicts other less accurate determinations. This problem is known as the proton radius puzzle. This new determination of the proton radius may affect the value of the Rydberg constant . This constant is related to many fundamental constants; in particular, links the two possible ways proposed for the redefinition of the kilogram, the Avogadro constant N(A) and the Planck constant h. However, the current relative uncertainty on the experimental determinations of N(A) or h is three orders of magnitude larger than the 'possible' shift of the Rydberg constant, which may be shown by the new value of the size of the proton radius determined from muonic hydrogen. The proton radius puzzle will not interfere in the redefinition of the kilogram. After a short introduction to the properties of the proton, we will describe the muonic hydrogen experiment. There is intense theoretical activity as a result of our observation. A brief summary of possible theoretical explanations at the date of writing of the paper will be given. The contribution of the proton radius puzzle to the redefinition of SI-based units will then be examined.     

Is the diatom sex clock a clock?

The unique life cycle of diatoms with continuous decreasing and restoration of the cell size leads to periodic fluctuations in cell size distribution and has been regarded as a multi-annual clock. To understand the long-term behaviour of a population analytically, generic mathematical models are investigated algebraically and numerically for their capability to describe periodic oscillations. Whereas the generally accepted simple concepts for the proliferation dynamics do not sustain oscillating behaviour owing to broadening of the size distribution, simulations show that a proposed limited lifetime of a newly synthesized cell wall slows down the relaxation towards a time-invariant equilibrium state to the order of a hundred thousand generations. In combination with seasonal perturbation events, the proliferation scheme with limited lifetime is able to explain long-lasting rhythms that are characteristic for diatom population dynamics. The life cycle thus resembles a pendulum clock that has to be wound up from time to time by seasonal perturbations rather than an oscillator represented by a limit cycle.     

Thermal Conductivity of a Molecular Crystal with Rotational Degrees of Freedom: Orientational Defect Scattering

Measurements of thermal conductivity of solid methane-deuteromethane solutions at equilibrium vapor pressure in the temperature range 1.2÷20 K are reported. The obtained dependences of thermal conductivity on temperature and concentration can be explained qualitatively assuming that the dominant mechanism of phonon scattering is connected with the interaction of phonons with the rotational motion of the molecules in all of the three orientational phases of the CH₄-CD₄ system. The contribution of the orientational defect scattering to the thermal conductivity is discussed in frame of the model of local changes in the moments of inertia of molecules.      

Is hair loss a reality in neuro-interventional radiology?

Reports in the literature of radiation-induced hair loss are becoming increasingly common. This work describes a retrospective dose study of patients (n = 958) undergoing diagnostic (primarily cerebral angiograms) and therapeutic (primarily cerebral embolisation) procedures in a neuro-interventional suite. A comparison of patient doses as dose area product (DAP) readings from a single-plane image intensifier system (mean DAP value of 8772 cGy cm2) were compared with patient doses from a flat panel biplane system (mean DAP value of 7855 cGy cm2). Over 80 % of patients requiring neuro-interventional procedures were found to undergo two procedures or more. An estimated 7 % of therapeutic procedures were found to reach the International Commission on Radiological Protection threshold for temporary epilation.     

Is diffusion,thermodiffusion, or advection a primary mechanism of indoor radon entry?

Revision of the current theory of indoor radon entry is given. It is shown that there is insufficient evidence to accept the pressure-driven mechanism as the dominant mechanism of radon infiltration in homes. The criticism of the US Environmental Protection Agency's policy is presented. The similitude theory of gas transfer in Knudsen's and transition zones is developed. Comparison of the theory with experimental data confirms the validity of the assumptions made. Application of the theory to air flow in clay is shown. This theory allows the average pore radius in the clay sample to be estimated. That radius was found to be of the order of the mean free path of air molecules at atmospheric pressure. It is shown that thermodiffusion gas flow in clay and concrete can greatly exceed the pressure-driven flow. The necessity of including thermodiffusion gas flow in a general model of radon indoor entry is substantiated.     

An evolutionary analysis of the innovation policy domain: Is there a paradigm shift?

Scientometrics - Researchers focus on understanding the nature of ecosystems and societies as well as explaining how paradigms change. These efforts are presented and disseminated through scholarly...