cssi/SciSciGPT-SciSciNet huggingface dataset:
Effects of dry fractures on matrix diffusion in unsaturated fractured rocks

[1] Matrix diffusion has been recognized as an important mechanism affecting solute transport through unsaturated fractured rock, where a significant portion of the fracture network remains relatively dry and inactive in conducting liquid flow. This simulation study shows that dry fractures act as strong diffusion barriers to solute transport when such fractures divide the matrix into discrete blocks. Where fracture surface roughness causes certain amount of direct contact between matrix blocks separated by a dry fracture, the contacts of the matrix blocks provide conduits for liquid flow and molecular diffusion across dry fractures. Simulation results indicate that the presence of dry fractures and their discontinuities can considerably affect solute transport in unsaturated fractured rock, depending on the magnitude of molecular diffusion.
A technical, economic, and environmental assessment of amine-based CO2 capture technology for power plant greenhouse gas control

Capture and sequestration of CO2 from fossil fuel power plants is gaining widespread interest as a potential method of controlling greenhouse gas emissions. Performance and cost models of an amine (MEA)-based CO2 absorption system for postcombustion flue gas applications have been developed and integrated with an existing power plant modeling framework that includes multipollutant control technologies for other regulated emissions. The integrated model has been applied to study the feasibility and cost of carbon capture and sequestration at both new and existing coal-burning power plants. The cost of carbon avoidance was shown to depend strongly on assumptions about the reference plant design, details of the CO2 capture system design, interactions with other pollution control systems, and method of CO2 storage. The CO2 avoidance cost for retrofit systems was found to be generally higher than for new plants, mainly because of the higher energy penalty resulting from less efficient heat integration as well ...
Control of the Electronic Structure of Organic Conductors as Exemplified by [NMP][TCNQ] Charge-Transfer Complexes

Through replacement of cations with neutral molecules of similar shape and polarizability in a highly conducting “metal-like” change-transfer organic conductor, the deliberate control of the electronic structure from a quarter to a half-filled band is possible. This goal has been achieved with the N-methylphenazinium (NMP) salt of the tetracyanoquinodimethane (TCNQ) anion by partial replacement of the cation with phenazine. A detailed study of the optical, electrical, and magnetic properties of these conducting molecular solids has lead to the evolution of a broad understanding of the physics of one-dimensional organic conductors and a reinterpretation of the mechanism of electron transport in such solids. Phenomena such as switching from a low coulomb repulsion two-chain conductor to a high coulomb repulsion one-chain conductor as well as soliton-assisted electron transport are observed.
Communication-optimal parallel algorithm for strassen's matrix multiplication

Parallel matrix multiplication is one of the most studied fundamental problems in distributed and high performance computing. We obtain a new parallel algorithm that is based on Strassen's fast matrix multiplication and minimizes communication. The algorithm outperforms all known parallel matrix multiplication algorithms, classical and Strassen-based, both asymptotically and in practice. A critical bottleneck in parallelizing Strassen's algorithm is the communication between the processors. Ballard, Demmel, Holtz, and Schwartz (SPAA '11) prove lower bounds on these communication costs, using expansion properties of the underlying computation graph. Our algorithm matches these lower bounds, and so is communication-optimal. It exhibits perfect strong scaling within the maximum possible range.Benchmarking our implementation on a Cray XT4, we obtain speedups over classical and Strassen-based algorithms ranging from 24% to 184% for a fixed matrix dimension n=94080, where the number of processors ranges from 49 to 7203.Our parallelization approach generalizes to other fast matrix multiplication algorithms.
Titanium deposition on coal liquefaction catalysts

Abstract Deactivation of catalysts in coal liquefaction hydrotreaters has been correlated with the deposition of carbonaceous materials and metals, especially iron and titanium. However, there are questions concerning the origin of the titanium, how it deposits, and the degree of deactivation that it causes. Using a microflow reactor, we contacted Shell 328 catalyst extrudates with hydrogenated creosote oil, with and without 0.07% titanium porphyrin, one of the many titanium compounds potentially responsible for depositing metal on catalyst. The experiments were conducted at 350°C, 500 psi hydrogen, and a space velocity of 2 g feed/g catalyst/h. At a catalyst age of 25 g feed/g catalyst the extrudates contained 3.9 wt% carbon and, with porphyrin, showed shell progressive poisoning at a loading of 0.7% titanium in the anatase form of TiO2 which is typical of deposition found in catalysts obtained from large scale liquefaction reactors. Catalyst activities determined by model compound reactions indicated little additional deactivation due to the titanium as compared to deactivation resulting from deposits of carbonaceous material alone.
Theoretical quasar emission-line ratios. V - Balmer continuum emission

Isothermal, isobaric models of quasar emission line regions are presented which include an improved treatment of radiative transfer in the bound-free continua, based on a generalization of frequency-integrated line transfer techniques and on the use of a probabilistic radiative transfer equation which explicitly distinguishes between the flux divergence coefficient and the photon escape probability. It is found that Balmer continuum emission can be obtained without compromising observed line ratios. It is also established that optically thin or thick Balmer continuum emission models with blended Fe II line are consistent with 4000-2000 A 'blue bump' observations, and that the improved radiative transfer treatment makes order-of-magnitude corrections to level populations and local cooling rates calculated with past techniques.
Pre-launch characterization of the WISE payload

The Wide-field Infrared Survey Explorer (WISE), launched on December 14, 2009, is a NASA-funded Explorer mission that is providing an all-sky survey in the mid-infrared with far greater sensitivity and resolution than any previous IR survey mission. The WISE science payload is a cryogenically cooled infrared telescope with four 1024x1024 infrared focal plane arrays covering from 2.8 to 26 μm, which was designed, fabricated, and characterized by Utah State University's Space Dynamics Laboratory. Pre-launch charaterization included measuring focus, repeatability, response non-linearity, saturation, latency, absolute response, flatfield, point response function, scanner linearity, and relative spectral response. We will provide a brief overview of the payload, discuss the overall characterization approach, review several pre-launch characterization methods in detail, and present selected results from ground characterization and early on-orbit performance.
Remote Sensing of Soil Moisture with Microwave Radiometers

Results are presented that were derived from measurements made by microwave radiometers during the March 1972 and February 1973 flights of National Aeronautics and Space Administration (NASA) Convair-9900 aircraft over agricultural test sites in the southwestern part of United States. The purpose of the missions was to study the use of microwave radiometers for the remote sensing of soil moisture. The microwave radiometers covered the 0.8- to 21-cm wavelength range. The results show a good linear correlation between the observed microwave brightness temperature and moisture content of the 0- to 1-cm layer of the soil. The results at the largest wavelength (21 cm) show the greatest sensitivity to soil moisture variations and indicate the possibility of sensing these variations through a vegetative canopy. The effect of soil texture on the emission from the soil was also studied and it was found that this effect can be compensated for by expressing soil moisture as a percent of field capacity for the soil. The results were compared with calculations based on a radiative transfer model for layered dielectrics and the agreement is very good at the longer wavelengths. At the shorter wavelengths, surface roughness effects are larger and the agreement becomes poorer.
Computed Tomography Enterography for Evaluation of Inflammatory Bowel Disease

Computed tomography enterography (CTE) has become a main modality for the evaluation of inflammatory bowel disease (IBD). It simultaneously offers visualization of the small bowel and extraintestinal status, which is helpful for diagnosing IBD. Crohn disease has long segmental enhancing wall thickening related with the eccentric longitudinal distribution. In addition, mural stratification, fibrofatty proliferation, positive comb sign by increased mesenteric vascularity and internal/perianal fistula are characteristics of Crohn disease and can be identified on CTE. Short segmental inflammatory wall thickening and the central low attenuated lymph nodes are favorable CT finding of intestinal tuberculosis. A geographic, relatively large, and deep penetrating ulcer with bowel wall thickening and mural hyperenhancement in ileocecal area are characteristics of intestinal Behcet disease. Each of CTE findings for the IBDs is helpful for differential diagnosis. The main disadvantage of this technique is the requisite radiation exposure of patients, particularly in young patients. However, recent development of advanced CT techniques is promising for radiation dose reduction without compromising diagnostic image quality.
A bio-inspired flow sensor

Accurate measurement of the turbulent flow is an important step toward understanding the mechanisms of many unknown phenomena. Turbulence generally can not be easily measured without significantly disturbing the original flow conditions. This paper introduces the efforts that aim to develop a bio-inspired sensor for monitoring turbulent flow. The sensor will consist of an array of micro-pillars or nano-pillars. Piezoelectric elements serve as transductors, which provides a key sensing element in the construction of micro-pillar. A prototype design was fabricated for the micropillar. The performance of sensing principle by this micropillar was evaluated and was found to be sensitive. The micropillar will be further refined into sensing arrays for real time sensing of flow turbulence.
The topological Hawaiian earring group does not embed in the inverse limit of free groups

Endowed with natural topologies, the fundamental group of the Hawaiian earring continuously injects into the inverse limit of free groups. This note shows the injection fails to have a continuous inverse. Such a phenomenon was unexpected and appears to contradict results of another author. AMS Classification 57M05, 14F35; 54H10, 22A10
A new method to obtain reproducible measurements on single-wavelength, single-angle-of-incidence, null-seeking, polarizer-compensator-sample-analyzer ellipsometers

Abstract A method is discussed which enables routine users of single-wavelength, single-angle-of-incidence, null-seeking polarizer-compensator-sample-analyzer ellipsometers to obtain reproducible measurement results on reasonably aligned production ellipsometers without tediously having to adjust and/or characterize them. This method is based on a numerical analysis, of data taken from a carefully prepared set of SiO 2 /Si samples, which determines a number of sample and null-seeking ellipsometer parameters. The method is shown to give results for ellipsometer alignment corrections equivalent to those obtained by standard, more tedious, procedures and it yields material parameters consistent with accepted values for the SiO 2 /Si system. Application of these results is demonstrated, including measurements on SRM-2530 standards obtained from the National Institute of Standards and Technology. We also propose that the error term, which is used in our numerical analysis to characterize the ellipsometer, should be used routinely as a gauge of the combined measurement and model errors for all samples that are measured.
Stability of fine tuned hierarchies in strongly coupled chiral models

Abstract A fine tuned hierarchy between a strongly coupled high energy compositeness scale and a much lower chiral symmetry breaking scale is a requisite ingredient in many models of dynamical electroweak symmetry breaking. Using a nonperturbative continuous Wilson renormalization group equation approach, we explore the stability of such a hierarchy against quantum fluctuations.
How a quark–gluon plasma phase modifies the bounds on extra dimensions from SN1987a

Abstract The shape of the neutrino pulse from the supernova SN1987a provides one of the most stringent constraints on the size of large, compact, “gravity-only” extra dimensions. Previously, calculations have been carried out for a newly-born proto-neutron star with a temperature of about 50 MeV at nuclear matter density. It is arguable that, due to the extreme conditions in the interior of the star, matter might be a quark–gluon plasma, where the relevant degrees of freedom are quarks and gluons rather than nucleons. We consider an energy-loss scenario where seconds after rebounce the core of the star consists of a hot and dense quark–gluon plasma. Adopting a simplified model of the plasma we derive the necessary energy-loss formulae in the soft-radiation limit. The emissivity is found to be comparable to the one for nuclear matter and bounds on the radius of extra dimensions are similar to those found previously from nuclear matter calculations.
ON THE EFFECT OF GIANT PLANETS ON THE SCATTERING OF PARENT BODIES OF IRON METEORITE FROM THE TERRESTRIAL PLANET REGION INTO THE ASTEROID BELT: A CONCEPT STUDY

In their model for the origin of the parent bodies of iron meteorites, Bottke et al. proposed differentiated planetesimals, formed in 1–2 AU during the first 1.5 Myr, as the parent bodies, and suggested that these objects and their fragments were scattered into the asteroid belt as a result of interactions with planetary embryos. Although viable, this model does not include the effect of a giant planet that might have existed or been growing in the outer regions. We present the results of a concept study where we have examined the effect of a planetary body in the orbit of Jupiter on the early scattering of planetesimals from the terrestrial region into the asteroid belt. We integrated the orbits of a large battery of planetesimals in a disk of planetary embryos and studied their evolutions for different values of the mass of the planet. Results indicate that when the mass of the planet is smaller than 10 M⊕, its effects on the interactions among planetesimals and planetary embryos are negligible. However, when the planet mass is between 10 and 50 M⊕, simulations point to a transitional regime with ∼50 M⊕ being the value for which the perturbing effect of the planet can no longer be ignored. Simulations also show that further increase of the mass of the planet strongly reduces the efficiency of the scattering of planetesimals from the terrestrial planet region into the asteroid belt. We present the results of our simulations and discuss their possible implications for the time of giant planet formation.
Noninvasive quantification of mitral regurgitation in dilated cardiomyopathy: correlation of two Doppler echocardiographic methods.

Abstract The presence and severity of functional mitral regurgitation were quantified by Doppler echocardiography in 17 patients with dilated cardiomyopathy and no evidence of primary valvular disease. Mitral regurgitant fraction was greater than 20% in 11 of the 17 patients, and exceeded 40% in four patients. Total stroke volume, calculated from the difference between end-diastolic and end-systolic volumes obtained by two-dimensional echocardiography, correlated well with mitral valve inflow determined by Doppler echocardiography (r = 0.90, p
Extended Horn sets in propositional logic

The class of Horn clause sets in propositional logic is extended to a larger class for which the satisfiability problem can still be solved by unit resolution in linear time. It is shown that to every arborescence there corresponds a family of extended Horn sets, where ordinary Horn sets correspond to stars with a root at the center. These results derive from a theorem of Chandresekaran that characterizes when an integer solution of a system of inequalities can be found by rounding a real solution in a certain way. A linear-time procedure is provided for identifying “hidden” extended Horn sets (extended Horn but for complementation of variables) that correspond to a specified arborescence. Finally, a way to interpret extended Horn sets in applications is suggested.
Goldstino Decoupling in Spontaneously Broken Supergravity Theories

If the gravitino is sufficiently light and stable it will behave as an effective massless neutrino species at the time of nucleosynthesis. Depending on the temperature at which it decouples from the thermal bath in the early universe, the gravitino mass will be bounded by the primordial 4He abundance. Assuming a conservative estimate that the number of neutrino families, Nv < 3.6, superlight gravitinos with a mass m32 ≲ 10−6 eV are ruled out. This bound is weaker than previous estimates because the Goldstino annihilation cross section was overestimated.
DETECTION OF MOLECULAR HYDROGEN ORBITING A "NAKED" T TAURI STAR

Astronomers have established that for a few million years, newborn stars possess disks of orbiting gas and dust. Such disks, which are likely sites of planet formation, appear to disappear once these stars reach ages of yr; yet, ≥10 7 yr is thought necessary for giant planet formation. If disks dissipate in less time than 6 (5–10) # 10 is needed for giant planet formation, such planets may be rare and those known around nearby stars would be anomalies. Here we report the discovery of H2 gas orbiting a weak-lined T Tauri star heretofore presumed nearly devoid of circumstellar material. We estimate that a significant amount of H 2 persists in the gas phase, but only a tiny fraction of this mass emits in the near-infrared. We propose that this star possesses an evolved disk that has escaped detection thus far because much of the dust has coagulated into planetesimals. This discovery suggests that the theory that disks are largely absent around such stars should be reconsidered. The widespread presence of such disks would indicate that planetesimals can form quickly and giant planet formation can proceed to completion before the gas in circumstellar disks disperses. Subject headings: circumstellar matter — infrared: stars — solar system: formation — stars: individual (DoAr 21) — stars: pre–main-sequence
An Ethnographic Study of the Mathematical Ideas of a Group of Carpenters

Abstract Mathematical knowledge, primarily the practice of arithmetic, which is developed outside of educational institutions by people engaged in their daily working and domestic activities, has been documented. The idea that different forms of mathematics may develop as a result of different modes of thinking and different environmental demands across cultural groups, has been suggested by research in ethnomathematics. However, there exist no clear guidelines for recognising and describing such culture-specific mathematics, which may differ significantly from the conventional view of mathematics. This article describes a study of the mathematical ideas of a group of carpenters, focusing mainly on their geometric ideas, and provides an account of the methodological strategy which was used. The researcher conducted an ethnographic study over the period of six months, working as an apprentice with a group of carpenters in Cape Town, South Africa. One descriptive example of an interaction with two carpenters involved in problem solving is analyzed in this article. The results show that the carpenters engaged in a wide variety of mathematizing activities in order to solve the problem.
Policy Responses to Aid Surges in Countries with Limited International Capital Mobility: The Role of the Exchange Rate Regime

Summary We study the role of the exchange rate regime, reserve accumulation, and sterilization policies in the macroeconomics of aid surges. Absent sterilization, a peg allows for almost full aid absorption—an increase in the current account deficit net of aid—delivering the same effects as those of a flexible regime but with a necessary increase in inflation. Regardless of the regime, policies that limit absorption and result in large accumulation of reserves—are welfare reducing: they help reduce the real appreciation (and inflation under the peg), but at the expense of reducing private consumption and investment, and therefore medium-term growth.
CPU coverage evaluation using automatic fault injection

A method has been developed for evaluating central processing unit (CPU) coverage by automatically injecting faults into actual CPU hardware while it is executing relevant test software. A special hardware test fixture is used which contains the CPU under evaluation, program and data memory, and a terminal interface. The test fixture is connected to a microcomputer controller and an in-circuit read only memory (ROM) emulator. The faults injected are "stuck-at-1," "stuck-at-0," and open on the appropriate integrated circuit pins, plus the altered state of every microprogram memory bit. The effect of each fault is determined by observing the status of the watchdog monitor. Data reduction is performed after each run on a separate host computer, and summary results are tabulated. N digital avionics systems the central processing unit (CPU) is obviously the dominant functional element, upon which many other elements are dependent in order to perform correctly related interface and control tasks. Normally, there are arrays of system monitors, in both hardware and software, which have an inherently overlapping capability to detect CPU malfunctions. The combined effectiveness of these monitors determines the total CPU fault coverage. However, since many of these monitors are themselves dependent upon CPU operation, there is a critical "topdown" relationship between the monitors which must be considered. In particular, a software monitor is of little subsequent value in the presence of a CPU fault unless one of the two following conditions is present. 1) It is actually executed, and it produces the planned fault detection results, and the fault detection is properly communicated to and acted upon by the ultimate hardware control elements in the system. 2) It causes fault detection elsewhere when it is not executed, and the fault detection is properly communicated to and acted upon by the ultimate hardware control elements in the system. In simplest terms, software monitors depend upon a "rational" CPU; that is, a CPU which is at least able to follow the normal program flow without making addressing or branching errors. If this is not the case, then how can one guarantee that the software monitor is executed? If it is possible to detect the fault of concern without executing the software monitor, then why is the monitor present? The point is that it is critically necessary to have a CPU monitoring scheme which establishes the minimum CPU fault coverage that is required to support all other monitoring activity. Such a monitoring scheme must straddle the hardware-software boundary so that external communication is absolutely guaranteed. In the simple terms introduced in the preceding, such a monitor must be able to detect all faults resulting in "irrational" CPU operation. In most modern digital avionic systems, the monitor which does these things is the so-called "watchdog" monitor (WDM) (or alternately the "heartbeat" or "deadman" timer monitor). The WDM usually operates in relation to the timer
The relationship between proton conductivity and water permeability in composite carboxylate/sulfonate perfluorinated ionomer membranes

Abstract Composite carboxylate/sulfonate Nafion ® films were prepared with different ratios of anion equivalents as a test of the relationship between proton conductivity and water permeability in perfluorinated ionomers. Substitution of carboxylate groups for sulfonate groups dramatically reduced water permeability and modestly reduced proton conductivity in the films. Small angle X-ray scattering (SAXS) was used to probe the polymer microstructure and showed that with up to 20% carboxylate equivalents, the size of hydrated ionic domains within the ionomer remains constant. Water sorption measurements showed little decrease in water uptake with increased carboxylate functionality, supporting the SAXS data. Methanol/water permeability experiments showed that the carboxylate moieties slow the diffusion of both water and methanol, with no permselectivity of water. Results indicate that the proton transport mechanism is altered by addition of carboxylic acid. As such, the composites may show interesting behavior in H 2 /O 2 and direct methanol fuel cells. It is proposed that permeability and conductivity measurements may provide an inexpensive and simple screening tool for early evaluation of new experimental proton exchange membranes.
An algorithm for placement of interconnected elements based on minimum wire length

The efficient placement of components has taken on increased importance because of microminiaturization techniques. Packaging techniques are permitting higher density of components. As the components are mounted closer and closer, less and less room becomes available between components for interconnections. Under these circumstances, the layout of circuitry becomes a difficult and time consuming task for the designer. One approach often used by designers is to group together elements which are functionally related so as to reduce the length of interconnections. If the designer could place the elements in such a way that every element connects only to its nearest neighbors, the problem of routing the interconnections would be somewhat simplified.
Segment-coupling Prins cyclizations

Abstract A segment-coupling Prins cyclization was developed involving (1) esterification, (2) reductive acetylation and (3) Lewis acid promoted cyclization. A model for the bis-tetrahydropyran segment of phorboxazole was successful assembled using this new method.
Determination of ICRF antenna fields in the vicinity of a 3-D Faraday shield structure

Abstract A three-dimensional (3-D) magnetostatic analysis developed at Oak Ridge National Laboratory has been used to calculate the electromagnetic transmission properties of representative Faraday shield designs. The analysis uses the long-wavelength approximation to obtain a 3-D Laplace solution for the magnetic scalar potential over one poloidal period of the Faraday shield, from which the complete magnetic field distribution may be obtained. Once the magnetic field distributions in the presence and absence of a Faraday shield are known, the flux transmission coefficient can be found, as well as any change in the distributed inductance of the current strap. The distributed capacitance of the strap can be found from an analogous 3-D electrostatic calculation, enabling the phase velocity of the slow-wave structure to be determined. Power dissipation in the shield may be estimated by equating the surface current on a perfect conductor with the surface magnetic field and using this surface current in conjunction with the finite conductivities of the shield materials to obtain the power distribution due to eddy current heating.
Highly efficient O-glycosylations with p-tolyl thioribosides and p-TolSOTf.

A wide variety of p-tolyl thioriboside donors are examined for O-ribosylations of primary and secondary alcohols. p-Tolylsulfenyl trifluoromethanesulfonate (p-TolSOTf) is very effective in promotin...
On the etiology of clubbing of the fingers.

Abstract Clubbing of the fingers and toes, and the more severe “pulmonary” osteoarthropathies and periostitides, occur when there is arterial anoxia due to congenital or acquired lesions or residence at high altitude. It occurs in many disorders in which the erythrocyte sedimentation rate is rapid, but arterial oxygen saturation normal. In all these cases the vascular bed is wide, blood flow rapid, and the tissue warmer than normal. That rapid sedimentation rates, with intravascular rouleaux formation, interfered with oxygenation of the tissues by decreasing the diffusion surface per unit of hemoglobin had long ago been suggested by Fahraeus. In this review it is suggested that with escape of rouleaux through the arteriovenous anastomoses so numerous in the fingers and toes, rapid blood flow and high levels of arterial and venous oxygen saturation may be present simultaneously with low oxygen tension in the digital tissues. Thus, rapid rates of blood flow and low tissue oxygen tension would provide the same mechanism for clubbing in chronic infections, neoplasms, or metabolic defects leading to abnormal fibrinogen and globulin levels, as in the classical cases of arterial anoxia. The most rapidly evolving and the most severe types of osteoarthropathy are seen in cases of mediastinal and lung tumors where the sedimentation rates are rapid and arterial anoxia is present. Here the two types of anoxia may coexist. In rheumatoid arthritis, in Raynaud's disease, and in Buerger's disease clubbing is rare, although tissue anoxia is severe in the latter two and rapid sedimentation rates are characteristic of the former. But in all of these, blood flow and tissue temperatures are low in the tips of the extremities. It is thereby concluded that for the development of clubbing low oxygen tensions must occur in tissues which are warm and in which the blood flow is greater than normal.
A study of PCAC for the nonperturbative improvement of the Wilson action

We present an exploratory study for the nonperturbative determination of the coefficient of the O(a) improvement term to the Wilson action, csw. Following the work by Luscher et al., we impose the PCAC relation as a nonperturbative improvement condition on csw, without, however, using the Schrodinger functional in our calculation.
Constant light exposure induces damage and squamous metaplasia in Harderian glands of albino mice

Abstract Harderian glands from control albino mice kept in a cyclical light/dark environment had tubulo-alveoli comprised of lipid-filled glandular epithelial cells. The porphyrin content of the gland measured 122 μg/100 mg gland. Constant light exposure for 24 hr caused exopthalmos grossly. Histologically most of the secretory cells were swollen and the lumens of many tubulo-alveoli were obliterated; a few areas of the gland showed damage. The porphyrin content had decreased to 116 μg/100 mg gland. After 3 days of constant light exposure the tubulo-alveoli were markedly altered. Lipid and cellular debris filled the lumens, and lining cells were highly irregular, ranging in shape from columnar to squamous. The porphyrin content had decreased to 72 μg/100 mg gland and leukocytes and macrophages were abundant. Despite this extensive damage a number of tubulo-alveolar epithelial cells were observed undergoing mitosis. After 7 days of constant exposure to light, some tubulo-alveolar epithelial cells had undergone squamous metaplasia, and the porphyrin content had dropped markedly to 50 μg/100 mg gland. These pronounced cellular changes are believed to result from a direct effect of light on the gland.
Forces between stable non-BPS branes

Abstract As a step toward constructing realistic brane world models in string theory, we consider the interactions of a pair of non-BPS branes. We construct a dyonic generalization of the non-BPS branes first constructed by Bergman, Gaberdiel and Sen as orbifolds of D-branes on T 4 / Z 2 . The force between a dyonic brane and an electric brane is computed and is found to vanish at a non-trivial critical separation. This equilibrium point is unstable. For smaller separations the branes coalesce to form a composite dyonic state, while for larger separations the branes run off to infinity. We suggest generalizations that will lead to potentials with stable local minima.
Strings from IIB matrices

Abstract The D-string action is constructed from IIB matrices. A space-time commutator is essential in this construction. This hints at the central role of the space-time uncertainty relation in a unified formulation of strings. Vertex operators of fundamental strings are also discussed.
THE DIXMIER-DOUADY CLASS OF GROUPOID CROSSED PRODUCTS

that satisﬁes Fell’s condition, and αwill denote a continuous action of Gon Avia isomorphisms. Thus the pair (A,α) is exactly what is needed to deﬁne an el-ement in the Brauer group Br(G) as deﬁned in [4, Deﬁnition 2.14]. As a specialcase of [3, Theorem 1], it follows that the groupoid crossed product C
Crystals in gels and Liesegang rings

Providing the first comprehensive overview of the method of crystal growth in gels, Professor Henisch reviews the field, covering the underlying physics as well as the empirical experience of growth techniques accumulated over the past century. In addition, the book discusses the phenomenon of periodic precipitation, which often governs the distribution of crystal in laboratory growth systems. For the first time, computer techniques are brought to bear on the subject, the diffusion equations being solved numerically, in association with the conditions governing precipitations and crystal growth.
Temporal and Spatial Variability of Great Lakes Ice Cover, 1973–2010*

AbstractIn this study, temporal and spatial variability of ice cover in the Great Lakes are investigated using historical satellite measurements from 1973 to 2010. The seasonal cycle of ice cover was constructed for all the lakes, including Lake St. Clair. A unique feature found in the seasonal cycle is that the standard deviations (i.e., variability) of ice cover are larger than the climatological means for each lake. This indicates that Great Lakes ice cover experiences large variability in response to predominant natural climate forcing and has poor predictability. Spectral analysis shows that lake ice has both quasi-decadal and interannual periodicities of ~8 and ~4 yr. There was a significant downward trend in ice coverage from 1973 to the present for all of the lakes, with Lake Ontario having the largest, and Lakes Erie and St. Clair having the smallest. The translated total loss in lake ice over the entire 38-yr record varies from 37% in Lake St. Clair (least) to 88% in Lake Ontario (most). The tot...
Viscous Effects on Cooled Pitot Tubes in Hypersonic Low Reynolds Number Flows

The influence of low Reynolds number viscous effects on blunt-nose stagnation pressure is investigated analytically for near-continuum hypersonic ideal gas flows around cooled bodies. It is shown that normal stress within the boundary layer acts to increase stagnation pressure slightly but that the usually neglected pressure slip at the wall introduces a significant opposing effect when the wall is cooled. Closed-form relationships describing this behavior as a function of Reynolds number, wall temperature ratio, and gas type are developed
Interwoven supramolecular arrays via the noncovalent polymerization of pseudorotaxanes

Abstract This review describes how the noncovalent polymerization of pseudorotaxanes—inclusion complexes in which thread-like molecules or ions interpenetrate macrorings’ central cavities without the formation of a mechanical bond—leads to the production of interwoven supramolecular arrays in the solid state. The noncovalent synthesis of these polymeric supramolecular architectures requires the independent and simultaneous operation of at least two different orthogonal recognition algorithms, viz. a threading algorithm, for the formation of the pseudorotaxane, and a noncovalent polymerization algorithm, that permits interpseudorotaxane association in the crystal. The information required for the operation of these orthogonal recognition algorithms is preprogrammed into the covalent frameworks of the interwoven supramolecular arrays’ precursors. Several different types of intermolecular interactions have been employed by crystal engineers for the noncovalent synthesis of interwoven supramolecular arrays in the solid state, in particular, metal–ligand, π – π stacking and hydrogen bonding interactions.
Small-Scale Structure of O VI Interstellar Gas in the Direction of the Globular Cluster NGC 6752

In order to study the small-scale structure of hot interstellar gas, we obtained Far Ultraviolet Spectroscopic Explorer interstellar O vi absorption spectra of four post-extreme horizontal branch stars in the globular cluster NGC 6752 (, d = 3.9 kpc, z = -1.7 kpc). The good-quality spectra of these stars allow us to measure both lines of the O vi doublet at 1031.926 and 1037.617 A. The close proximity of these stars permits us to probe the hot interstellar gas over angular scales of only 2, corresponding to spatial scales of 2.5-10.1 pc. On these scales we detect no variations in the O vi column density and velocity distribution. The average column density is log langleN(O vi)\rangle = 14.34±0.02 (log langleN⊥(O vi)\rangle = 13.98). The measured velocity dispersions of the O vi absorption are also indistinguishable. Including the earlier results of Howk et al., this study suggests that interstellar O vi is smooth on scales Δθ 12', corresponding to a spatial scale of 10 pc, and is quite patchy at larger scales. Although such small scales are only probed in a few directions, this suggests a characteristic size scale for the regions producing collisionally ionized O vi in the Galaxy.
Cervical cytology in women with mental retardation

Objective To examine our experience with performing pelvic examination and obtaining cervical cytology in women with mental retardation. Methods From November 1985 to October 1992, 658 women were seen in our clinic for women with mental disabilities. A standardized clinic visit form was completed for each woman. Of these records, 574 were available for analysis. All charts were reviewed for data on the level of retardation, incidence of sedation, success in performing pelvic examination and Papanicolaou smear, technique used for cervical smear, and pathology results of the cervical cytology. Results Of the 574 women, 289 (50%) had severe, 69 (12%) moderate, and 31 (5%) mild retardation. In 185 (32%), the exact level of retardation was not established. During the study period, 1235 pelvic examinations were analyzed. Within this group, 845 examinations could be completed initially, 177 required the use of sedation (14%), and 213 (17%) examinations could not be completed. Of the 845 examinations, 706 cervical smears were available for analysis. Of these, only 243 (34%) contained endocervical cells. Two abnormal cytology results were found (0.3%). Of the 177 examinations done with sedation, 44 women (25%) still could not be examined. Cytology specimen results were obtained in 124 of the examinations, and 40 (32%) of these specimens contained endocervical cells. No cytologic abnormalities were present. In a cervical smear technique comparison, endocervical cells were present in 58% of 161 standard speculum examinations and in 18% of 93 cotton-swab tests ( P Conclusion Cytology specimens can be obtained without sedation in most mentally retarded women. Only one-third of Papanicolaou smears contained endocervical cells from examinations with sedation as well as those without. The cotton-swab technique has a significantly lower endocervical cell collection rate than the standard speculum technique. The incidence of abnormalities on cytologic examination appears to be low compared with other populations of women. Whether this is due to suboptimal smears, lower prevalence of human papillomavirus, or a combination of both remains to be resolved.
Bacterial Urinary Tract Infections in Diabetes

Diabetes mellitus has a number of long-term effects on the genitourinary system. These effects predispose to bacterial urinary tract infections in the patient with diabetes mellitus. Bacteriuria is more common in diabetic women than in nondiabetic women because of a combination of host and local risk factors. Upper tract infection complications are also more common in this group. Diabetic patients are at higher risk for intrarenal abscess, with a spectrum of disease ranging from acute focal bacterial pyelonephritis to renal corticomedullary abscess, to the renal carbuncle. A number of uncommon complicated urinary tract infection complications occur more frequently in diabetics, such as emphysematous pyelonephritis and emphysematous pyelitis. Because of the frequency and severity of urinary tract infection in diabetic patients, prompt diagnosis and early therapy is warranted. A plain abdominal radiograph is recommended as a minimum radiographic screening tool in the patient with diabetes presenting with systemic signs of urinary tract infection. Ultrasonography or further radiographic studies such as CT scanning may also be warranted, depending on the clinical picture, to identify upper urinary tract complications early for appropriate intervention.
A new bisphosphonate reagent for the synthesis of (Z)-olefins and bis(trifluoroethyl) phosphonates

Abstract A new Wadsworth-Emmons reagent, tetrakis(2,2,2-trifluoroethyl) methylenediphosphonate, was prepared and its reaction with aldehydes to yield (Z)-vinyl phosphonates is described. Additionally, an example of a base catalyzed isomerization of a (Z)-vinyl phosphonate to the corresponding (E)-allylic phosphonate is also discussed.
Volcanic forcing of climate over the past 1500 years: An improved ice core-based index for climate models

[1] Understanding natural causes of climate change is vital to evaluate the relative impacts of human pollution and land surface modification on climate. We have investigated one of the most important natural causes of climate change, volcanic eruptions, by using 54 ice core records from both the Arctic and Antarctica. Our recently collected suite of ice core data, more than double the number of cores ever used before, reduces errors inherent in reconstructions based on a single or small number of cores, which enables us to obtain much higher accuracy in both detection of events and quantification of the radiative effects. We extracted volcanic deposition signals from each ice core record by applying a high-pass loess filter to the time series and examining peaks that exceed twice the 31-year running median absolute deviation. We then studied the spatial pattern of volcanic sulfate deposition on Greenland and Antarctica and combined this knowledge with a new understanding of stratospheric transport of volcanic aerosols to produce a forcing data set as a function of month, latitude, and altitude for the past 1500 years. We estimated the uncertainties associated with the choice of volcanic signal extraction criteria, ice core sulfate deposition to stratospheric loading calibration factor, and the season for the eruptions without a recorded month. We forced an energy balance climate model with this new volcanic forcing data set, together with solar and anthropogenic forcing, to simulate the large-scale temperature response. The results agree well with instrumental observations for the past 150 years and with proxy records for the entire period. Through better characterization of the natural causes of climate change, this new data set will lead to improved prediction of anthropogenic impacts on climate. The new data set of stratospheric sulfate injections from volcanic eruptions for the past 1500 years, as a function of latitude, altitude, and month, is available for download in a format suitable for forcing general circulation models of the climate system.
Optimal Memoryless Relays With Noncoherent Modulation

We derive optimal memoryless relays for the case of noncoherent modulation over additive white Gaussian noise (AWGN) channels with or without fading. The derivation is flexible, as it can be applied to any binary hypothesis observed at the relay. We investigate several channels, including random phase and fading, and apply different modulation schemes, namely on-off-keying (OOK) and orthogonal frequency-shift-keying (FSK). We find that at low signal-to-noise ratios (SNR) the relay censors its observation, as it only transmits at nonzero energy if the observations seem reliable. Compared to the known results that optimal memoryless relays for the case of coherent binary-phase-shift-keying (BPSK) are combinations of soft-information and a hard-limiter, the noncoherent relays have considerably less emphasis on soft-information and converge much faster to the hard-limiter.
Protection of alcohols as their (p-methoxybenzyloxy)methyl ethers.

Abstract Protection of even tertiary alcohols can be accomplished by treatment with p -methoxybenzyl chloromethyl ether. Deprotection can be effected under mild conditions using the DDQ reaction conditions described by Oikawa.
A Macro model of frequently changing mobile networks to perform flow and access control

The area covered by a mobile ad hoc network consists of obstacles that inhibit transmission and areas where communications can take place. Physical structures, such as buildings, that block transmission, or lakes, where forwarding nodes cannot be located, are permanent obstacles. Temporary obstacles are created as mobile nodes enter or leave an area. Our hypothesis is that the spaces between nearby obstacles are bottlenecks that inhibit the flows in the network. We partition the network into areas that are encompassed by obstacles and bottlenecks. All of the nodes in an area are treated as a single super node, and the bottlenecks between areas are the links between the super nodes. As individual nodes move, the flows and paths in the model change more slowly than the paths and flows between the individual nodes. We apply flow control algorithms to the model and perform admission control within a super node based on the flows that are assigned by the flow control algorithm. We apply the model to the Columbia University campus, and use max-min, fair bottleneck flow control to assign the flows. Our hypothesis is verified for this example.