cssi/SciSciGPT-SciSciNet huggingface dataset:
Simulation of shock wave propagation in single crystal and polycrystalline aluminum

Abstract A thermoelastic–viscoplastic constitutive model has been developed to model high strain rate deformation in single crystal metals. The thermoelastic formulation employs a material Eulerian strain measure, which has recently been shown to converge more rapidly than traditional Lagrangian strain measures for material undergoing large compression. The viscoplastic formulation is based on the physics of dislocation glide and generation as well as their interaction. This model has been implemented into a one-dimensional, extended finite-difference formulation for anisotropic materials and is used to model shock wave propagation in aluminum single crystals, polycrystals, and pre-textured polycrystals for peak shock pressures ranging from 2 to 110 GPa. The model was able to reproduce experimentally measured particle velocity profiles from both plate impact and laser shock experiments performed on single crystals and polycrystals. Simulations showed that the orientation distribution in vapor-deposited polycrystalline samples can affect the observed elastic precursor decay by a factor of two, as well as change the observed response in laser shock experiments from a dual to single-wave shock structure. Simulations performed on cold rolled aluminum samples showed that an increase in the cold rolling reduction caused a decrease in the number of active slip systems, as well as a decrease in the heterogeneity of total accumulated slip. Finally, a coarse-grained analytical model was developed from results of plane wave simulations and was shown to effectively reproduce plastic heterogeneity induced by single crystal orientations. Simulations in this work showed that single crystal effects play a key role in dictating the macroscopically observed response, which suggests high strain rate experiments that omit detailed initial microstructural characterization do not provide sufficient information for complete mechanistic understanding or model validation.
Identification of forgeries in handwritten petitions for ballot propositions

Many governments have some form of "direct democracy" legislation procedure whereby individual citizens can propose various measures creating or altering laws. Generally, such a process is started with the gathering of a large number of signatures. There is interest in whether or not there are fraudulent signatures present in such a petition, and if so what percentage of the signatures are indeed fraudulent. However, due to the large number of signatures (tens of thousands), it is not feasible to have a document examiner verify the signatures directly. Instead, there is interest in creating a subset of signatures where there is a high probability of fraud that can be verified. We present a method by which a pairwise comparison of signatures can be performed and subsequent sorting can generate such subsets.
A moving screw dislocation in piezoelectromagnetic ceramics

A moving screw dislocation in polarized ceramics is analyzed using the fully dynamic equations of piezoelectromagnetism. Analytical solutions for the mechanical and electromagnetic fields associated with the dislocation are obtained.
MULTIDIMENSIONAL REALIZATION OF LARGE SCALE UNCERTAIN SYSTEMS FOR MULTIVARIABLE STABILITY MARGIN COMPUTATION

SUMMARY The prevailing framework for robust stability and performance analysis requires that the uncertain system be written as a linear fractional transformation of the uncertain parameters. This problem is algebraically equivalent to the problem of deriving the state space realization for a multidimensional transfer function matrix, for which a systematic algorithm was recently provided by Cheng and DeMoor. 1 In this work an algorithm is developed that reduces the dimension of the realizations while improving numerical accuracy, reducing computational expense, and reducing run-time memory requirements. Such improvements are required for the realization of large scale uncertain systems, which have large numbers of inputs, outputs, states, and=or uncertain parameters.
Low-Energy Ion−Surface Reactions of Pyrazine with Two Classes of Self-Assembled Monolayers: Influence of Alkyl Chain Orientation

Collisions of pyrazine with two classes of self-assembled monolayer (SAM) films are employed to determine whether surface confinement and the resulting alkyl chain orientation, influences low-energy ion−surface reactions. SAM films formed from n-alkanethiols (CH3(CH2)n−S−Au, n = 14−17) and 4-(4-alkoxyphenylbenzenethiols (4-(4-CH3(CH2)mOC6H4)−C6H4−S−Au, m = 14−17) chemisorbed onto Au (111) substrates are known to exhibit a chain-length-dependent odd−even effect that places the terminal C−C bond into different orientations. Ion−surface collisions (20 eV) of pyrazine molecular ion (M = m/z 80) with these surfaces yield reaction product ions corresponding to the addition of hydrogen atoms ([M + H]+ = m/z 81) and methyl groups ([M + CH3]+ = m/z 95) from the surface to the probe ion. Differences in the relative abundance of the reaction product ions are measured as a function of chain length for both classes of SAM film. SAM films with odd chain lengths (n, m = 14 and 16) have a consistently higher abundance of...
Composite Solution Procedure for 3-D Flow Simulations on a Multi-Box Grid

Fluid flows in biological systems are typically complex, due to factors such as non-Newtonian behavior of biochemical fluids and complex geometry, as well as the interaction of muscles and fluid. With the advent of modern computational technology, these problems are gradually resolved. The present research illustrates two such examples. Grid generation is essential for conducting numerical simulation of fluid flow. In the present research, a new grid generation technique is developed and implemented into a flow solver. This technique enables one to create a grid for complex geometry using only a single computational zone. The flow field can therefore be analyzed without iteration between zones. The numerical scheme developed for solving the grid generation equations is an extension of the traditional three-dimensional Douglass-Gunn Alternating-Direction Implicit (ADI) scheme. A unique feature of the demonstrated grid generation scheme is the concept of multi-box computational domains. In this scheme, the physical domain is mapped onto a multi-box geometry in the computational space, rather than a single box as the traditional methods do. Therefore, the numerical scheme is adjusted accordingly. Flow simulations were performed using the software INS3D, which employs the method of artificial compressibility. This method transforms the Navier-Stokes equations into a system of hyperbolic-parabolic equations, and then marches along the pseudo-time axis until the velocity field becomes divergence-free. Two biological flow problems were analyzed using the aforementioned method. The flow field in an arterial graft as well as in the Left atrium (LA) of the human heart was studied. The effect of Reynolds number and flow-division ratio is examined in the graft problem. The Reynolds number effect is demonstrated via the presence of a helical flow structure and the overall pressure drop. The flow-division ratio alters the flow field in a way that moves the stagnation points. The simulated flow field closely resembles that observed clinically. The steady-state simulation of the flow field in the left atrium of the human heart provided information about the long-term performance of the heart chamber. The simulation demonstrates the existence of low wall shear region, which is therefore susceptible to blood clot formation. This observation also agrees with the clinical findings. In summary, the present research demonstrates application of CFD techniques in the analysis of flow in a biological system. A new grid generation technique is realized, and proved to be useful in simulating these flows. The flow simulation results provide insights into the system, and may be useful for clinical reference.Copyright © 2006 by ASME
The decision to enter a randomized trial of tamoxifen for the prevention of breast cancer in healthy women: An analysis of the tradeoffs

OBJECTIVE : Interest in breast cancer prevention has led to the Breast Cancer Prevention Trial (BCPT), a controversial randomized trial of tamoxifen for women at risk for breast cancer. The goal of our study was to determine whether the potential benefits of enrolling in the randomized trial of prophylactic tamoxifen outweigh the potential risks. METHODS : We used a decision analytic model based on the available data on tamoxifen treatment benefits in women with breast cancer and extrapolated to its use in healthy women. RESULTS : For a 50-year-old woman with a breast cancer risk twice that of the average woman her age, the BCPT offers an increase in life expectancy of about 9 days, a gain that is modest compared with other health interventions. For women ages 35 to 60 who meet the minimum risk of breast cancer for trial eligibility, the trial increases life expectancy by about 8 or 9 days. Assumptions about the effect of tamoxifen on the incidence of endometrial and liver cancer and on quality of life associated with tamoxifen did not alter our findings. CONCLUSIONS : Advocates and opponents of the BCPT should temper their concerns to reflect the modest absolute benefits and harms associated with the trial. Although women at increased risk for breast cancer should be aware of the likely overall benefit associated with entry into the trial, for most women, entry into the BCPT is unlikely to alter substantially their length of life, in either a beneficial or harmful manner.
An ion microprobe study of the partitioning of trace elements between clinopyroxene and liquid in the system diopside-albite-anorthite

Abstract The partitioning of trace elements (Sc, Ti, Sr and Sm) between diopsidic clinopyroxene and liquid was studied experimentally in the system diopside-albite-anorthite at 1250°C, 1300°C and 1345°C at 1 atm. Twelve different bulk compositions were selected to study the effects of temperature and chemical composition. A Cameca ion microprobe was used to determine trace element concentrations in both clinopyroxene and liquid. Experiments of different run duration 1 4 8 days) showed that equilibrium was approached in less than 4 days at 1275°C. Equilibrium was also evaluated by a reversal run. A series of runs of constant bulk composition but with variable trace element contents showed that Henry's Law was obeyed over concentration ranges of the trace elements similar to those encountered in natural systems. The partition coefficients show significant ranges: Sc, 0.345~2.61; Ti, 0.084~0.214; Sr, 0.075~0.136; Sm, 0.054~0.328; the values are comparable with those obtained experimentally by other investigators. The partition coefficients vary as a function of both temperature and chemical composition. The experimental results are discussed in terms of exchange equilibria using the Bottinga-Weill silicate melt model. It is demonstrated that analytical uncertainties of both major and trace elements play an important role in understanding trace element exchange equilibria; propagation of analytical errors in the thermodynamic treatment is equally important.
Low-cost branch folding for embedded applications with small tight loops

Many portable and embedded applications are characterized by spending a large fraction of execution time on small program loops. To improve performance many embedded systems use special instructions to handle program loop executions. These special instructions, however, consume opcode space, which is valuable in the embedded computing environments. In this paper, we propose a hardware technique for folding our branches when executing these small loops. This technique does not require any special branch instructions. It is based on the detection and utilization of certain short backward branch instructions (sbb). A sbb is any PC-relative branch instruction with a limited backward branch distance. Once an sbb is detected, its displacement field is used by the hardware to identify the actual program loop size. It does so by loading this negative displacement field into a counter and incrementing the counter for each instruction sequentially executed. As the count approaches zero, the hardware folds out the sbb by predicting that it is always taken. The hardware overhead for this technique is minimal. Using a 5-bit increment counter, the performance improvement over a set of embedded applications is about 7.5%.
New high-temperature noble-metal thermocouple pairing

A new thermocouple pairing was formed by combining thermocouple elements from two existing commercially available thermocouples to form a new combination (Ir–40 Rh/Pt–40 Rh) thermocouple. The output of this new pairing is nearly linear with temperature, and approximately equal to the output of one of the originating pairs (Ir–40 Rh/Ir), and more than double that of the other pair (Pt–40 Rh/Pt–20 Rh). This new pairing was evolved during a search for a noble‐metal thermocouple combination which could operate above the temperature limit of a Pt–13 Rh/Pt thermocouple and have a higher oxidation resistance than an Ir–40 Rh/Ir thermocouple.
Doppler-free, multiwavelength acousto-optic deflector for two-photon addressing arrays of Rb atoms in a quantum information processor.

We demonstrate a dual wavelength acousto-optic deflector (AOD) designed to deflect two wavelengths to the same angles by driving with two RF frequencies. The AOD is designed as a beam scanner to address two-photon transitions in a two-dimensional array of trapped neutral Rb87 atoms in a quantum computer. Momentum space is used to design AODs that have the same diffraction angles for two wavelengths (780 and 480 nm) and have nonoverlapping Bragg-matched frequency response at these wavelengths, so that there will be no cross talk when proportional frequencies are applied to diffract the two wavelengths. The appropriate crystal orientation, crystal shape, transducer size, and transducer height are determined for an AOD made with a tellurium dioxide crystal (TeO2). The designed and fabricated AOD has more than 100 resolvable spots, widely separated band shapes for the two wavelengths within an overall octave bandwidth, spatially overlapping diffraction angles for both wavelengths (780 and 480 nm), and a 4 μs or less access time. Cascaded AODs in which the first device upshifts and the second downshifts allow Doppler-free scanning as required for addressing the narrow atomic resonance without detuning. We experimentally show the diffraction-limited Doppler-free scanning performance and spatial resolution of the designed AOD.
Compton Scattering by K-Shell Electrons. II. Nonrelativistic Dipole Approximation

The dipole approximation of the nonrelativistic cross section for Compton scattering by electrons bound in the ground state of a hydrogenlike atom, obtained by the present author, is computed and discussed. In this approximation the cross-section differential with respect to the angles and energy of the scattered photon is proportional to ${C}_{1}+{C}_{2}{cos}^{2}\ensuremath{\theta}$, where $\ensuremath{\theta}$ is the scattering angle of the photon. The coefficients ${C}_{1}$, ${C}_{2}$ are combinations of Appell functions ${F}_{1}$, depending on the atomic number $Z$ and the energies of the initial and final photons ${\ensuremath{\kappa}}_{1}$, ${\ensuremath{\kappa}}_{2}$ by means of the dimensionless variables ${k}_{i}=\frac{{\ensuremath{\kappa}}_{i}}{{Z}^{2}\mathcal{R}}$, $i=1, 2$, where $\mathcal{R}$ is the rydberg. In order to compute the Appell functions, these were first continued analytically and expressed in terms of other hypergeometric functions of two variables, which under our circumstances admit convergent series expansions. These were then summed numerically. The incident photon energies considered lie in the interval $1.05\ensuremath{\le}{k}_{1}\ensuremath{\le}20$. For each value ${k}_{1}$ the coefficients ${C}_{1}$ and ${C}_{2}$ were computed for a number of values of ${k}_{2}$ ($0\ensuremath{\le}{k}_{2}\ensuremath{\le}{k}_{1}\ensuremath{-}1$). Special attention was given to the end points ${k}_{2}=0$ and ${k}_{2}={k}_{1}$. ${C}_{1}$ and ${C}_{2}$ turn out to be monotonically decreasing functions of ${k}_{2}$ presenting the infrared-divergent behavior $\frac{1}{{k}_{2}}$ for ${k}_{2}\ensuremath{\rightarrow}0$. The limitations of the result due to retardation corrections are considered.
Extracellular coat in developing human palatal processes: Electron microscopy and ruthenium red binding†

The prefusion epithelium of human palatal processes was examined for evidence of specialization which might facilitate epithelial adherence with the opposing palatal process. A surface coat stained with ruthenium red (RR) was found on all apical aspects of the palatal epithelium. In the prefusion regions, RR staining was also observed in the spaces between the superficial cells of the epithelium and in necrotic cells. Adjacent oral and nasal epithelium excluded the RR below the level of the apical junctional complex. In the absence of RR, a dense material was observed in the most superficial intercellular spaces of the prefusion region. Many superficial cells in the area were in various stages of necrosis. The combination of degenerating surface cells and an accumulation of a poly-anionic substance such as glycoprotein may facilitate epithelial adherence between opposing human palatal processes.
PLATINUM AND PALLADIUM INCORPORATION INTO PHOSPHATE/VIOLOGEN-PHOSPHONATES OF ZIRCONIUM AND HAFNIUM : SYNTHESIS AND CHARACTERIZATION

Abstract We have continued previous efforts to synthesize and characterize a microporous metal phosphate/viologen-phosphonate compound, [(ZrF) 2 (PO 4 )(O 3 PCH 2 CH 2 -4,4′-bipyridinium-CH 2 CH 2 PO 3 )] ⋅ F·2H 2 O, ZrPO PV . A derivative of this material has been shown to be an efficient catalyst for the production of hydrogen peroxide from hydrogen and oxygen. This paper has two objectives—one is to optimize the synthetic routes leading to the preparation of MPO PV (M=zirconium or hafnium) and the second is to characterize MPO PV and the derivatives formed by Pt or Pd incorporation by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray powder diffraction (XRD), inductively coupled plasma-mass spectrometry (ICP-MS) and X-ray absorption fine structure analysis (XAFS). Powder XRD data have shown much higher crystallinity in MPO PV samples prepared by hydrothermal methods than those prepared by reflux methods. In the hydrothermal synthesis, the amount of mineralizer (HF) present controlled the crystallite size (as determined from TEM micrographs). The larger the quantity of HF in the bomb, the larger the size of the crystals but the lower the yield of the MPO PV material. Crystal sizes of about 2.5 μm in length and 0.15 μm in diameter have been made with very large quantities of HF as mineralizer (10 times the required stoichiometric amount). Ion exchange of the material by PdCl 4 2− has resulted in the incorporation of the PdCl 4 2− ions in place of X − in the material. This has been confirmed by XAFS studies that demonstrate the oxidation state of Pd is 2+ and show four Cl atoms bound to Pd. Upon reduction it has been confirmed (by XAFS) that the palladium exists as metal with oxidation state of zero. Ion exchange by PdCl 4 2− and PtCl 4 2− and subsequent reduction of the material suspension by hydrogen result in the formation of separate Pt and Pd colloids in the close vicinity of the crystallites. TEM micrographs show clearly that the Pt metal obtained after reduction forms much smaller particles in comparison to Pd. These exchanged and reduced materials have also been investigated as catalysts for production of hydrogen peroxide in mixed acetone/water medium. The production of hydrogen peroxide is enhanced by increasing amounts of Pd in the catalyst. Hydrogen peroxide yields are the highest for catalysts containing only Pd as opposed to a mixture of Pt and Pd.
A specific sequence of the laminin alpha 2 chain critical for the initiation of heterotrimer assembly.

Triple-stranded laminin molecules assemble via an α-helical coiled-coil structure spanning approximately 600 amino acid residues of each chain. We reported that the C termini of the β1 and γ1 chains direct the specific dimer and trimer assembly (Utani, A., Nomizu, M., Timpl, R., Roller, P. P., and Yamada, Y.(1994) J. Biol. Chem. 269, 19167-19175). In this study, we focused on the mechanism of trimer formation of the α2 chain utilizing three different approaches. First, competition assays using mutated recombinant α2 chain defined a 25-amino acid sequence at the C terminus of the long arm as an essential site for assembly with β1 and γ1 chain. Site-specific mutations and synthetic peptides of this site revealed that both positively charged amino acid residues and the α-helical structure within this site were critical. Second, overexpression studies of recombinant α2 chain long arm confirmed that the C-terminal end was critical for the trimer assembly within NIH 3T3 cells. Third, circular dichroism spectroscopic examination of the complexes reconstituted in vitro revealed dynamic conformational changes of the α2 and γ1 chains in the process of assembly. These studies also revealed that the proper folding of the extreme C terminus of α2 chain was critical for the stability of trimer. From these data, it is concluded that the C terminus of α2 chain long arm is required for the effective initiation of laminin heterotrimer assembly.
Improving county government in North Carolina

Davidson County wipes out deficit, reduces tax rate, and simplifies government in first year under centralized administration.
The influence of the characteristics of the activating polyelectrolyte in the preparation and on the properties of interpolymer ion exchange membranes. II. Further experimental studies on the sorption, desorption, and permeation of polyelectrolyte in collodion membranes of high porosity☆

Abstract In the preceding paper the question was left open as to which extent the uptake of polyelectrolyte by collodion membranes of high porosity is limited by the size of the polyelectrolytes or by their adsorbability, both of which strongly depend on the composition of the impregnating solution. Likewise, the question of the stability of such membranes was not considered. Three sets of semiquantitative test experiments based on theoretical considerations were carried out to answer these questions. 1. 1. Polyethylene sulfonic acid (PESA), due to its structure, can be expected to undergo only very limited van der Waals interaction with and adsorption on an inert matrix whatever its degree of neutralization or the ionic strength of the impregnating solutions may be. Impregnating solutions containing PESA of relatively low molecular weight with which steric hindrance could be ruled out as a limiting factor did indeed not yield membranes of significant electrochemical activity. 2. 2. A characteristic predictable difference in the stability of highly porous polystyrene sulfonic acid (PSSA) and of polyacrylic acid (PAA) membranes was confirmed experimentally. PSSA membranes which were prepared with impregnating solutions containing 1.0 M NaCl are highly stable when immersed in solutions of high or medium ionic strengths but lose much of the adsorbed PSSA when placed in distilled water. Contrariwise, PAA membranes prepared by impregnation with PAA in the acidic state and in the absence of neutral electrolyte lose only relatively small quantities of the polyelectrolyte on prolonged immersion in 0.1 M NaCl. 3. 3. The diffusion of PSSA and PAA across membranes of high porosity is dependent, predictably, in a similar manner on the ambient solution concentration and, in the case of PAA, on the degree of neutralization. These observations prove that the uptake of polyelectrolytes by collodion membranes of high porosity, and the stability of such membranes, are determined essentially by adsorptive forces and are influenced only to a very minor degree by steric hindrance, provided the polyelectrolytes are not excessively large relative to the pores of the membranes.
The Administration of Sponsored Programs. Handbook for Developing and Managing Research Activities and Other Projects.

(1984). The Administration of Sponsored Programs: Handbook for Developing and Managing Research Activities and other Projects. The Journal of Higher Education: Vol. 55, No. 4, pp. 541-543.
Implementation of Democratic Social Choice Functions

A social choice function is said to be implementable if and only if there exists a game form such that for all preference profiles an equilibrium strategy n-tuple exists and any equilibrium strategy n-tuples of the game yield outcomes in the social choice set. A social choice function is defined to be minimally democratic if and only if whenever there exists an alternative which is ranked first by n-1 voters and is no lower than second for the last voter, then the social choice must be uniquely that alternative. No constraints are placed on the social choice function for other preference profiles. Using the usual definitions of equilibria for n-person games—namely Nash and strong equilibria—it is shown here that over unrestricted preference domains, no minimally democratic social choice function is implementable. The same result holds in certain restricted domains of the type assumed by economists over public goods spaces. We then show that a different notion of equilibrium—namely that of sophisticated equilibrium—allows for implementation of democratic social choice functions also having further appealing properties. The implication is that models of democratic political processes cannot be based on the standard equilibrium notions of Nash or strong equilibria.
Microstructure and its relationship to deformation processes in amorphous polymer glasses

The microdeformation morphology of a number of vinyl polymers with bulky side chains (type I) and arylene polymers with flexible oxygen linkages (type II) was studied by electron microscopy. The polyarylenes crazed only near the glass transition while the polyvinyls exhibited a crazing regime that extended to liquid nitrogen temperatures. In addition significantly less plastic strain was localized in type II glass crazes relative to those in type I glasses. In compatible blends of polystyrene (PS) and 2,6-dimethyl poly(phenylene oxide) (2MPPO), ca. 30% 2MPPO was sufficient to induce a transition from type I to type II crazing behavior. Small amounts of PS suppressed the low-temperature 2MPPO β relaxation but enhanced the intermediate transition of 2MPPO at higher temperatures. Blending increased the conformational energy of the 2MPPO chain and improved interchain packing. The propensity for the polymer glass to form sharp shear bands at the expense of diffuse bands was increased by a decrease in the conformation energy of the polymer chain and an improvement in the glassy state packing.
Infant Craniospinal Ultrasonography: Beyond Hemorrhage and Hydrocephalus

Ultrasonography is widely used for screening for neonatal intracranial hemorrhage, hydrocephalus, and cord tethering in young infants. Proper interpretation of infant cranial and spinal ultrasound examinations requires not only familiarity with the appearances of these disorders, but also recognition of imaging artifacts capable of mimicking pathology and awareness of developmental variants and conditions that occupy a borderline position along the spectrum from normal to abnormal. This article will review the current understanding of the ultrasonographic characteristics and clinical relevance of these imaging artifacts, developmental variants, and quasi-pathologic conditions to avoid diagnostic pitfalls and guide appropriate patient management.
Pediatric diabetic ketoacidosis, fluid therapy, and cerebral injury: the design of a factorial randomized controlled trial

Treatment protocols for pediatric diabetic ketoacidosis (DKA) vary considerably among centers in the USA and worldwide. The optimal protocol for intravenous (IV) fluid administration is an area of particular controversy, mainly in regard to possible associations between rates of IV fluid infusion and the development of cerebral edema (CE), the most common and the most feared complication of DKA in children. Theoretical concerns about associations between osmotic fluid shifts and CE have prompted recommendations for conservative fluid infusion during DKA. However, recent data suggest that cerebral hypoperfusion may play a role in cerebral injury associated with DKA. Currently, there are no existing data from prospective clinical trials to determine the optimal fluid treatment protocol for pediatric DKA. The Pediatric Emergency Care Applied Research Network FLUID (FLuid therapies Under Investigation in DKA) study is the first prospective randomized trial to evaluate fluid regimens for pediatric DKA. This 13-center nationwide factorial design study will evaluate the effects of rehydration rate and fluid sodium content on neurological status during DKA treatment, the frequency of clinically overt CE and long-term neurocognitive outcomes following DKA.
Study of Vibronic, Spin-Orbit and Vibronic-Spin-Orbit Couplings of Formaldehyde with Applications to Radiative and Non-Radiative Processes

With the recent availability of large amounts of experimental data, theoretical models of radiative and nonradiative processes can be tested in detail. For this purpose, the absolute calculation of radiative and non-­radiative rate constants is required. The expression for the non-radiative rate constant consists of two parts, one from the electronic motion (the pro­moting part) and the other from the nuclear motion (the statistical part). All recent theoretical work has been focused on the calculation of the non-radiative rate constant of one single vibronic state relative to another so that the promoting part of the rate constant is cancelled and hence has been concerned mainly with the Franck–Condon factor calculation (the statistical part of the rate constant). That the calculation of the statistical part of the rate constant cannot provide a critical test for a theory of radiationless transitions is obvious. In the present investigation, the theory of radiationless transitions to be tested is that originally proposed by Robinson and Frosch and later developed by Lin & Bersohn, Siebrand & Henry, Freed, Nitzan & Jortner and Fischer. According to this theory, one way to calculate the promoting part of the non-radiative rate constant is to invoke the vibronic coupling for the internal conversion and to invoke the vibronic coupling plus the spin-orbit coupling and/or the vibronicspin-orbit coupling for the intersystem crossing. A numerical calculation is carried out for the internal conversion 1 A 2 → 1 A 1 and the intersystem crossing 1 A 2 → 3 A 2 of formaldehyde by using simple m. os. For radiative transitions, we calculate the lifetimes of the states, 3 A 2 ( n ↔ π * ), 1 A 2 ( n ↔ π * ), 1 B 1 ( n ↔σ*), and 1 A 1 ( π ↔ π * ). The corresponding transition moments are given. For symmetry forbidden transitions, we compared the Herzberg–Teller theory with the importance of the correc­tion to the breakdown of the adiabatic approximation. It is shown that for formaldehyde, the B.–O. correction is approximately one order of magnitude smaller than the first order vibronic coupling.
Stresses and strains in the cone-shaped carotid sinus and their effects on baroreceptor functions

Abstract Two models are introduced to compute the stresses and strains inside the wall of the cone-shaped carotid sinus: a two-layered cylindrical disc model and a two-layered spherical cone model. While they differ in complexity and approach, they both yield very similar stress-strain distributions for various physiological load conditions. These stress-strain distributions are important for strain sensitive baroreceptors in several ways. (a) Both the size and the orientation of the baroreceptors change as strain levels in the wall change. (b) Large stress differences occur at the border between the media and the adventitia which could cause large baroreceptor deformations. (c) Two distinct solutions with different stress-strain fields exist for the cylindrical disc model. A wwitch from one solution to the other during a normal pressure cycle would also cause large baroreceptor deformations.
Muscle function during takeoff and landing flight in the pigeon (Columba livia)

This study explored the muscle strain and activation patterns of several key flight muscles of the pigeon (Columba livia) during takeoff and landing flight. Using electromyography (EMG) to measure muscle activation, and sonomicrometry to quantify muscle strain, we evaluated the muscle function patterns of the pectoralis, biceps, humerotriceps and scapulotriceps as pigeons flew between two perches. These recordings were analyzed in the context of three-dimensional wing kinematics. To understand the different requirements of takeoff, midflight and landing, we compared the activity and strain of these muscles among the three flight modes. The pectoralis and biceps exhibited greater fascicle strain rates during takeoff than during midflight or landing. However, the triceps muscles did not exhibit notable differences in strain among flight modes. All observed strain, activation and kinematics were consistent with hypothesized muscle functions. The biceps contracted to stabilize and flex the elbow during the downstroke. The humerotriceps contracted to extend the elbow at the upstroke-downstroke transition, followed by scapulotriceps contraction to maintain elbow extension during the downstroke. The scapulotriceps also appeared to contribute to humeral elevation. Greater muscle activation intensity was observed during takeoff, compared with mid-flight and landing, in all muscles except the scapulotriceps. The timing patterns of muscle activation and length change differed among flight modes, yet demonstrated that pigeons do not change the basic mechanical actions of key flight muscles as they shift from flight activities that demand energy production, such as takeoff and midflight, to maneuvers that require absorption of energy, such as landing. Similarly, joint kinematics were consistent among flight modes. The stereotypy of these neuromuscular and joint kinematic patterns is consistent with previously observed stereotypy of wing kinematics relative to the pigeon's body (in the local body frame) across these flight behaviors. Taken together, these observations suggest that the control of takeoff and landing flight primarily involves modulation of overall body pitch to effect changes in stroke plane angle and resulting wing aerodynamics.
A Walrasian Theory of Money and Barter

We study a barter economy in which each good is produced in two qualities and no trader can distinguish between the qualities of those goods he neither consumes nor produces. We show that in competitive equilibrium there exists a (unique) good—the one for which the discrepancy between qualities is smallest—that serves as the medium of exchange: this good mediates every trade. Equilibrium is inefficient because production of the medium would be lower if it were not for its mediating role. Introducing fiat money enhances welfare by eliminating this distortion. However, high inflation drives traders back to the commodity medium.
Toxic reactions evoked by glutaraldehyde-fixed pericardium and cardiac valve tissue bioprosthesis

Bovine pericardial tissue and tissue-derived bioprosthesis fixed in glutaraldehyde and stored in either glutaraldehyde or formaldehyde can induce cytotoxic reactions even after prolonged washing due to the slow leaching of the chemicals used for crosslinking and sterilizing. Sequential rinsing for up to 60 min was still not sufficient to eliminate cytotoxic effects. On the other hand, satisfactory results were obtained when cardiac valves made from glutaraldehyde fixed pericardium were stored in a solution containing 0.02% of propyl-hydroxy-benzoate and 0.18% methyl-hydroxy-benzoate. The valves stored in this solution and rinsed three times for 1 min in normal saline showed few signs of residual cytotoxicity. Rinsing in a solution containing glycine was partially effective in neutralizing the cytotoxic effect, and this or similar approaches offer good possibilities. The use of Chang cells grown in culture provides an excellent quantitative assay for the assessment of residual cytotoxicity and for evaluating the host response to different methods of fixation, storage, and rinsing of tissue derived bioprosthesis.
Approach to the Patient with Postpartum Thyroiditis

Postpartum thyroiditis (PPT) is the occurrence of de novo autoimmune thyroid disease, excluding Graves' disease, in the first year postpartum. The incidence of PPT is 5.4% in the general population, and it is increased in individuals with other autoimmune diseases such as type 1 diabetes mellitus. The classic presentation of PPT of hyperthyroidism followed by hypothyroidism is seen in 22% of cases. The majority of women with PPT experience an isolated hypothyroid phase (48%), with the remainder experiencing isolated thyrotoxicosis (30%). Up to 50% of women who are thyroid antibody positive (thyroid peroxidase antibody and/or thyroglobulin antibody) in the first trimester will develop PPT. Symptoms are more common in the hypothyroid phase of PPT and include fatigue, dry skin, and impaired memory. Despite multiple studies exploring the relationship between PPT and postpartum depression, or postpartum depression in thyroid antibody-positive euthyroid women, the data are conflicting, and no firm conclusions can be reached. Long-term follow-up of women who had an episode of PPT reveals a 20-40% incidence of permanent primary hypothyroidism. In a single study, selenium administration significantly decreased the incidence of PPT, but replication of the findings is needed before the recommendation can be made that all pregnant thyroid peroxidase antibody-positive women receive selenium. The indication for treating the hyperthyroid phase of PPT is control of symptoms, whereas treatment of the hypothyroid phase of PPT is indicated for symptomatic relief as well as in women who are either breastfeeding or attempting to conceive.
Premature guidance about whole-genome sequencing.

Recently, several success stories about clinical use of whole-genome sequencing (WGS) and/or whole-exome sequencing (WES) have been reported. In some cases, sequencing led to improved decision-making and prognosis, and in at least a few cases, led to successful therapeutic interventions. Importantly, in each case, sequencing was performed on an individual with a serious clinical problem and the results returned related to the disorder. At the American College of Medical Genetics and Genomics (ACMG) meeting in Phoenix (AZ, USA) in March 2013, the ACMG presented new recommendations on the return of incidental findings in clinical care. It recommended that incidental findings be sought out and reported regardless of age and that the results be reported to patients (or surrogates), regardless of their preferences. These recommendations were made despite the drafting Working Group’s acknowledgement “that there was insufficient evidence about benefits, risks and costs of disclosing incidental findings to make evidence-based recommendations” [1]. It is our opinion that the ACMG recommendations clearly contravene respect for patients and shared decision-making at the clinical level and represent a setback to evidence-based medicine and the responsible development of societal policy. This article addresses five related issues: Guideline development; ‘Incidental’ findings; Informed consent; The ‘best interest of the child’ standard; The wider implications of the recommendations.
A Revolution Scheduled on a Facebook Page

January 25th, 2011 marks a momentous day for Egypt, and perhaps for the world. The revolution was the largest in the history of the country. What makes it unique is the integral role that social media played in mobilizing the masses. In particular the "We are all Khalid Said" Facebook page served as the national communication corridor which prompted action. This manuscript examines the specific role of the Facebook page in mobilizing a critical mass. Through a detailed quantitative content analysis of the page's activity, the manuscript captures the granular online communications that lead up to the Egyptian revolution. Social mobilization theory is utilized to illustrate how the page was able to incite such mobilization. Results show that the administrators of the “We are all Khalid Said” Facebook page implemented a process with five key missions: 1) Creating an injustice frame, 2) Broadcasting activities of defiance, 3) Emotionally inflaming and inspiring people, 4) Engaging participants, and 5) Organizing a concerted action plan.
The Life and Death of Epithelia During Inflammation: Lessons Learned from the Gut

Epithelial cells form protective barriers that physically separate an organism from the outside world. Rather than being merely static, impregnable shields, epithelia are highly dynamic structures that can adjust their proliferation, differentiation, and death in response to intrinsic and extrinsic signals. The advantages as well as pitfalls of this flexibility are highlighted in inflammatory disorders such as inflammatory bowel diseases and psoriasis, which are characterized by a chronically dysregulated homeostasis of the epithelium. In recent years, it has become increasingly apparent that epithelial cells communicate with their surroundings through converging, integrated signaling cascades and that even minor alterations in these pathways can have dramatic pathologic consequences. In this review, we discuss how inflammatory cytokines and other signaling molecules, directly or through cross talk, regulate epithelial homeostasis in the intestine, and we highlight parallels and differences in a few other organs.
Unsupervised hyperspectral image classification using blind source separation

This paper presents an unsupervised classification algorithm for hyperspectral remotely sensed imagery based on blind source separation. Since the area covered by a single pixel in such an image is very large, the reflectance of a pixel is the mixture from all the materials resident in this area. A contrast function consisting of the mutual information minimization and orthogonality among the outputs, is defined to separate the assumed linear mixture so as to achieve soft classification. In order to reduce the computational complexity, a Neyman-Pearson detection theory based eigen-thresholding method is used to estimate the number of classes, followed by a band selection technique to select a smaller number of bands used in the learning algorithm. The preliminary result using an AVIRIS experiment demonstrates the feasibility of the proposed algorithm.
Melody and Mirth on Washington Street: John Ordway and Blackface Minstrelsy in Antebellum Boston

On Tuesday 27 April 1880, the Boston Evening Transcript published a lengthy obituary of John Pond Ordway, “a prominent citizen of Boston” who had been “identified in many important enterprises” in ...
Effect of proteasome inhibitors on the release into the cytosol of free polymannose oligosaccharides from glycoproteins

Prompted by previous observations which suggested that the release of polymannose oligosaccharides shortly after the cotranslational N-glycosylation of proteins is a function of the ER-associated quality control system (Moore and Spiro (1994) J. Biol. Chem., 269, 12715-12721), we evaluated the effect which proteasome inhibitors have on the appearance of these free saccharide components. Employing as a model system castanospermine-treated BW5147 mouse T-lymphoma cells in which accelerated degradation of the T-cell receptor (TCR) alpha subunit takes place (Kearse et al. (1994) EMBO J., 13, 3678-3686), we noted that both lactacystin and N-acetyl-L-leucyl-L-leucyl-L-norleucinal, but not leupeptin, brought about a rapid and substantial reduction in the release of free polymannose oligosaccharides into the cytosol during pulse-chase studies, while the oligosaccharides in the intravesicular compartment remained unchanged, as measured by streptolysin O permeabilization. This inhibition was furthermore selective in that it affected solely the components terminating in a single N-acetylglucosamine residue (OS-GlcNAc(1)) and not the oligosaccharides terminating in a di-N-acetylchitobiose sequence (OS-GlcNAc(2)), which reside primarily in the intravesicular compartment. Despite the quantitative effect of the proteasome inhibitors on the cytosolic oligosaccharides, the molar distribution of the triglucosyl OS-GlcNAc(1) species was unaffected. The decrease in cytosolic oligosaccharides brought about by proteasome inhibition was reflected in a pronounced increase in the stability of the TCRalpha subunit. Our findings suggest that the N-deglycosylation and proteasome mediated degradation are coupled events. On the basis of our data and those of others we propose that the quality control mechanism involves proteasomes associated with the cytosolic side of the endoplasmic reticulum acting in concert with a membrane situated N-glycanase. Such a complex by removing the carbohydrate units could facilitate the retrograde ER to cytosol translocation of glycoproteins.
Spatial movement optimization in Amazonian Eciton burchellii army ants

Foraging army ants face a problem general to many animals—how best to confront resource depletion and environmental heterogeneity. Army ants have presumably evolved a nomadic lifestyle as a way to minimize re-exploitation of previously foraged areas. However, this solution creates a challenge for an army ant colony: foraging by this colony and others creates a shifting landscape of food resources, where colonies should theoretically avoid their own previous foraging paths as well as those of other colonies. Here, we examine how colonies exploit this resource mosaic, using some of the optimality arguments first proposed and tested by Franks and Fletcher (1983), but with much larger data sets in a new location in SW Amazonia. Our data supported Franks and Fletcher’s (1983) model for systematic avoidance of raided areas during the statary phase, as well as a hypothesis of distance optimization between successive statary bivouacs. We also test and find significant evidence that foraging raids turn in opposite directions from the previous day’s directional angles more frequently than what would be expected if turning angles were distributed at random, which acts to move a colony away from recently exploited areas. This implies that colonies follow a straighter line path during the nomadic phase as opposed to a curved one, which acts to maximize distance between statary bivouacs. In addition to intra-colony movement optimization, we examine evidence for inter-colony avoidance from more than 330 colony emigrations and suggest that colony-specific pheromones are not necessarily repulsive to other colonies. Lastly, we compare our results with those of similar studies carried out at Barro Colorado Island (BCI), Panama. Despite a higher density of army ants in the SW Amazon region, colonies spend less time emigrating than their counterparts at BCI, which suggests a higher prey density in SW Amazonia.
Securing the future for nylon

Since its introduction over 50 years ago, nylon has proved a highly useful fibre in the clothing industry. In this article, Les Jacques looks at developments which have been made in nylon fibres to ensure its continuing importance in the industry.
Decomposing nonproduct from queueing lattices through simulated annealing

A simulated annealing technique is adapted to decompose the state transition lattice of a class of nonproduct form queueing models which are useful in studying the behaviour of computer systems. Only the lattices of type A structure are considered. Applying this technique, the lattice is decomposed into solvable subsets which can be solved sequentially. A large amount of computation time can be saved in this way. >