Hole Picture Research Articles

The hole picture: risks, decision making, purpose, regulations, and the future of body piercing

Can it be said that body piercing is ubiquitous, found across all socioeconomic groups? The major concentration is among adolescents and young adults 15 to 30 years old, in some studies, 50% of the population. Commonly identified physical risks are bleeding, tissue trauma, and bacterial infections; psychosocial risks are unhappiness, low self-esteem, and disappointment. The Health Belief Model is used to explain decision making; purposes for body piercing consistently center on personal expression (self-identity) and uniqueness. The international and US body piercing regulations are discussed, leading to the need for tracking complications globally and standardization of regulations. Proactive health education for clients and health providers remains a priority.

Strings, black holes and the extreme energy cosmic rays

In a large class of string and string inspired models the string excitation and black hole pictures invoked as an explanation of trans-GZK cosmic ray events are equivalent at high excitations. Single particle inclusive distributions are thermal, asymptotically at the Hagedorn temperature. Some observational consequences are briefly explored.

The hole picture

The hole picture

TeV string theories, mini black holes and trans-GZK cosmic rays

We review the proposal that trans-GZK cosmic ray interactions are caused by neutrino primaries. The primaries cause excitations of strings and give rise to extensive air showers (EAS) resembling EAS induced by nuclei. We also show that in ``low scale'' string models (of characteristic energy about 70TeV) the excited string and the mini black hole pictures are equivalent.

The Nature and Transport Mechanism of Hydrated Hydroxide Ions in Aqueous Solution

AbstractFor Abstract see ChemInform Abstract in Full Text.

The nature and transport mechanism of hydrated hydroxide ions in aqueous solution.

Compared to other ions, protons (H(+)) and hydroxide ions (OH(-)) exhibit anomalously high mobilities in aqueous solutions. On a qualitative level, this behaviour has long been explained by 'structural diffusion' the continuous interconversion between hydration complexes driven by fluctuations in the solvation shell of the hydrated ions. Detailed investigations have led to a clear understanding of the proton transport mechanism at the molecular level. In contrast, hydroxide ion mobility in basic solutions has received far less attention, even though bases and base catalysis play important roles in many organic and biochemical reactions and in the chemical industry. The reason for this may be attributed to the century-old notion that a hydrated OH(-) can be regarded as a water molecule missing a proton, and that the transport mechanism of such a 'proton hole' can be inferred from that of an excess proton by simply reversing hydrogen bond polarities. However, recent studies have identified OH(-) hydration complexes that bear little structural similarity to proton hydration complexes. Here we report the solution structures and transport mechanisms of hydrated hydroxide, which we obtained from first-principles computer simulations that explicitly treat quantum and thermal fluctuations of all nuclei. We find that the transport mechanism, which differs significantly from the proton hole picture, involves an interplay between the previously identified hydration complexes and is strongly influenced by nuclear quantum effects.

De Broglie-Bohm Interpretation for Analytic Solutions of the Wheeler-DeWitt Equation in Spherically Symmetric Space-Time

We discuss the implications of a wave function for quantum gravity, which involves nothing but 3-dimensional geometries as arguments and is invariant under general coordinate transformations. We derive an analytic wave function from the Wheeler-DeWitt equation for spherically symmetric space-time with the coordinate system arbitrary. The de Broglie-Bohm interpretation of quantum mechanics is applied to the wave function. In this interpretation, deterministic dynamics can be yielded from a wave function in fully quantum regions as well as in semiclassical ones. By introducing a coordinate system additionally, we obtain a cosmological black hole picture in compensation for the loss of general covariance. Our analysis shows that the de Broglie-Bohm interpretation gives quantum gravity an appropriate prescription to introduce coordinate systems naturally and extract information from a wave function as a result of breaking general covariance.

Underdoped Region of the 2D t-J Model

We apply the spin-wave theory modified for the paramagnetic state [1] to investigate normal-state properties of the 2D t-J model. Self-energy equations for hole and magnon Green’s functions are self-consistently solved in the Born approximation for the ranges of hole concentrations x ≲ 0.17 and temperatures T ≲ 150 K. In this region the hole spectrum differs essentially from a conventional metallic spectrum. A distinctive feature of the low-concentration spectrum is the spin-polaron band with the minimum energy (in the hole picture) at (π/2, π/2), small dispersion along the boundary of the magnetic Brillouin zone, and the extended van Hove singularity near (0, π). The shape and narrow width of this band (of the order of the exchange constant J ~ 0.1 eV) are determined by the short-range hole-magnon interaction which remains practically unchanged in the transition from long- to short-range order with the correlation length much larger than the lattice spacing. As a result, a part of the spin-polaron band is retained in the paramagnetic state and gives an intensive peak in the spectral function for wave vectors near the boundary of the magnetic Brillouin zone. In addition to this peak a broader less intensive maximum is formed from the incoherent continuum with the transition to paramagnetic state. The dispersion of the maximum resembles the dispersion of the nearest-neighbor band with the hopping constant t. For moderate doping this wider band crosses the Fermi level along the line shown in the inset of Fig. la.

Theory of Intermediate-Valence States in Sm Compounds

The intermediate-valence states of SmB 6 and SmS are described in terms of the periodic Anderson model comprised of the localized 4 f multiplet states 6 H 5/2 and 7 F 0 of two adjacent configurations 4 f 5 and 4 f 6 , the wide conduction band states represented by the plane wave functions, and the hybridizations between the 4 f and the conduction states. We take hole picture and introduce fermi operators representing the states of 6 H 5/2 and a bose operator for the 7 F 0 singlet for each Sm site. At low temperatures, the bosons form a condensate, and consequently the fermion states hybridize with the conduction-band states to become itinerant, accompanied with an anisotropic gap structure. The susceptibility is dominated by the Van Vleck contribution from the excited 7 F 1 level of 4 f 6 , while the 6 H 5/2 states of 4 f 5 gives a small Pauli-type contribution, in good agreement with experimental results.

Semiclassical decay of near-extremal black holes

Decay of a near-extremal black hole down to the extremal state is studied in the background field approximation to determine the fate of injected matter and Hawking pairs. By examining the behavior of light rays and solutions to the wave equation it is concluded that the singularity at the origin is irrelevant. Furthermore, there is most likely an instability of the event horizon arising from the accumulation of injected matter and Hawking partners there. The possible role of this instability in reconciling the D-brane and black hole pictures of the decay process is discussed.

Density of States of Strongly Correlated Electrons in DCNQI-Cu Salts

By making use of the periodic Anderson model with both the electron-phonon interaction and the transverse hopping, we examine the density of states at zero temperature for strongly correlated d electrons in DCNQI-Cu salt which undergoes a metal-insulator transition followed by three-fold periodicity of both a lattice distortion and a local spin. A slave-boson method is applied to the model expressed in terms of a hole picture in order to treat the local constraint strictly. There are both the coherent (band) component and the incoherent (localized) component in the metallic state. In the insulating state, all the electrons at the site with the local spin are incoherent and a small amount of both components remains at other sites.

Order-disorder and superconductivity in Ca-doped LaBa 2Cu 3O 7−δ

An analytical electron microscopy study has been undertaken on six superconductors with nominal compositions LaBa 2− x Ca x Cu 3O 7−δ ( x=0, 0.25, 0.5, 0.75, 1.0 and 1.5). Energy dispersive X-ray spectroscopy (EDXS) analysis shows that the Ca-dopant saturates at doping level x=0.5 for superconducting phases (1-2-3 phases) in these materials, and that further Ca-doping changes only the actual ratio of La/Ba cations and increases the amount of secondary phase Ca 2CuO 3. An 80 K T c plateau is found corresponding to this saturation. Convergent-beam electron diffraction (CBED) and transmission electron microscopy (TEM) results show not only that these high- T c 1-2-3 phases are tetragonal with P4/mmm symmetry, but also, based on the observation of several superstructures, that there exists an order-disorder transition in these Ca-doped 1-2-3 phases induced by the variations of La/Ba cation ratios over certain sites in the 1-2-3 unit cell. The high- T c superconductivity in these tetragonal 1-2-3 phases suggests that the Ca cations introduce holes into the bridging site between two conductive Cu-O 2 sheets. This alternative “bridging” hole picture is more general in the high- T c copper oxide family than the “transferring” picture associated with the orthorhombic 1-2-3 phases.

Brinkman-Rice transition in the three-band Hubbard model

The ${\mathit{U}}_{\mathit{d}}$=\ensuremath{\infty} three-band Hubbard model on a two-dimensional ${\mathrm{CuO}}_{2}$ network is studied based on a Gutzwiller wave function by use of the variational Monte Carlo (VMC) method, where ${\mathit{U}}_{\mathit{d}}$ is the Coulomb repulsion between holes on the Cu site (hole picture). The VMC results are compared with those of the Rice-Ueda-type Gutzwiller approximation (GA) in a half-filled band, where the average number of holes per Cu site is n=1. In the GA the Brinkman-Rice (BR) transition occurs at a finite value of ${\mathrm{\ensuremath{\Delta}}}_{0}$=(${\mathrm{\ensuremath{\varepsilon}}}_{\mathit{p}}$-${\mathrm{\ensuremath{\varepsilon}}}_{\mathit{d}}$)/2, and then the number of d holes becomes ${\mathit{n}}_{\mathit{d}}$=n=1. Whether the BR transition really occurs or not within the Gutzwiller wave function is discussed in detail. In finite systems the absence of the BR transition is shown analytically. The thermodynamic limit is examined assuming the asymptotic behavior of ${\mathit{n}}_{\mathit{d}}$ is given by a scaling function. The results of the finite-size scaling analysis suggest the absence of the BR transition as that in the single-band Hubbard model.

Local-density total-energy supercell description of excited-state properties of solids: Ce photoemission and inverse photoemission spectra.

A total-energy theoretical description of peak positions in the experimental photoemission and inverse photoemission spectra of Ce is presented. The linearized muffin-tin-orbital method and local-density theory are employed to calculate the electronic structure and total energy of the excited ''impurity'' atom inside a supercell. Both 4f valence-band spectra and 3d core-hole spectra are determined. The energy positions of the 4f excitations are derived from the total energy of appropriate final-state configurations with a localized hole or localized electron picture. The 3d core-hole and 4f valence-band excitations are compared with x-ray-photoemission experiments and inverse photoemission experiments. The results show that the peak positions in these spectra can be explained by ordinary screening effects, i.e., the availability of distinct groups of (metastable) final states for the photoemission process.

Many-body effect at metal-semiconductor junctions. II. The self energy and band structure distortion

For pt. I see abstr. A75119 of 1972. When a metal is placed upon the surface of a semiconductor the resulting changes in the electron interaction near the interface produce changes in the exchange and correlation potential. The most important aspect is that the potential changes differ with the state considered. In particular the reaction of the valence and conduction bands are very different causing changes in the band gap in the surface region. The image potential has opposite signs in the valence and conduction band corresponding to the semiclassical electron and hole picture; this is shown to be due to the screened exchange difference between the two bands. The screened exchange difference between the two bands is calculated numerically up to the surface for the two limiting cases of a covalent and ionic semiconductor. Finally the difference in behaviour of these two types is briefly discussed in the light of the results on Schottky barriers.