cssi/SciSciGPT-SciSciNet huggingface dataset:
An Unusual Case of Second-Degree A-V Block —A Study Using His Bundle Electrograms

His bundle electrograms were recorded in a patient with second degree A-V block, 2:1 conduction and a normal QRS duration. With this technique, the site of A-V block was localized to the area of the A-V node (intranodal block, usually Mobitz type I). Long-term monitoring did not demonstrate Wenckebach periods. Increasing the atrial rate by pacing was associated with increasing degrees of AV block (ie 2:1 to 4:1 AV conduction). This phenomenon has primarily been described with subnodal block. The findings in this case suggest that the decision for transvenous pacemaker insertion should, therefore, not be made solely on the determination of the site of A-V block.
Sampling-based optimal motion planning for non-holonomic dynamical systems

Sampling-based motion planning algorithms, such as the Probabilistic RoadMap (PRM) and the Rapidly-exploring Random Tree (RRT), have received a large and growing amount of attention during the past decade. Most recently, sampling-based algorithms, such as the PRM* and RRT*, that guarantee asymptotic optimality, i.e., almost-sure convergence towards optimal solutions, have been proposed. Despite the experimental success of asymptotically-optimal sampling-based algorithms, their extensions to handle complex non-holonomic dynamical systems remains largely an open problem. In this paper, with the help of results from differential geometry, we extend the RRT* algorithm to handle a large class of non-holonomic dynamical systems. We demonstrate the performance of the algorithm in computational experiments involving the Dubins' car dynamics.
Size dependence of HF vibrational frequency shift for ArnHF (n=1–14) van der Waals clusters via quantum five‐dimensional bound state calculations

HF vibrational frequency shifts for ArnHF (n=1–14) clusters have been determined for the first time using quantum 5D bound state calculations. Our results for n=1–4 clusters are in very good agreement with the available experimental data. The size dependence of the redshift is predicted to be very nonmonotonic.
Comparison of the Recent Drought in Texas to the Drought of Record Using Reanalysis Modeling

The current drought in Texas has become the second worst in the last 120 years, exceeded only by the 1950s drought of record. It is easy to compare the two in terms of area, length, and severity using the Palmer Drought Severity Index (PDSI), and the underlying atmospheric process can be reconstructed with data from the National Oceanic and Atmospheric Administration (NOAA) reanalysis model. Reanalysis is a comprehensive, global data set produced by the National Centers for Environmental Prediction. The historical surface observations, balloon soundings, and satellite data have been reprocessed or reanalyzed with a sophisticated computer model. Thus, it is possible to compare the 1950s drought and the current drought directly using data from the same model. The meteorological processes operating in these droughts showed similar patterns of 500 mb pressure, outgoing longwave radiation, and geopotential height.
What Are Risk Factors for 30-day Morbidity and Transfusion in Total Shoulder Arthroplasty? A Review of 1922 Cases

Background Total shoulder arthroplasty (TSA) is an effective treatment for end-stage glenohumeral joint pathology with good long-term results. Previous descriptions of morbidity and blood transfusion in TSA are limited by preoperative risk factors and postoperative complications considered and single-center studies.
Paleoproterozoic rocks of central Colorado: Accreted arcs or extended older crust?

Paleoproterozoic (1770–1735 Ma) bimodal volcanic rocks in central Colorado have been considered to represent southward growth of Laurentia by arc accretion. Although the bimodality of these rocks suggests an extensional continental setting rather than continental or oceanic arcs, there has been little evidence for pre–1800 Ma crust south of the Wyoming craton other than the 1840 ± 1 Ma Elves Chasm pluton in the Upper Granite Gorge of the Grand Canyon, Arizona. We report SHRIMP U-Pb ages of inherited zircons from metarhyolites and plutons in central Colorado that are latest Archean–earliest Proterozoic (2520–2000 Ma) and Trans-Hudson–Penokean (1878–1814 Ma). Associated quartzites contain detrital zircons with mean ages of 1735 Ma, indicating only local derivation. A meta-arkose, however, contains detrital zircons of Trans-Hudson–Penokean and Archean ages. We believe it likely that the 1900–1800 Ma Trans-Hudson–Penokean orogens, including Archean enclaves, extended farther south and west than is currently thought, and were the source of the bimodal volcanic rocks and associated plutons during the period 1770–1700 Ma.
Latino men's sexual behavior with transgender persons.

Male-to-female transgender persons are thought to be “vectors” for HIV/STI transmission, yet little quantitative information exists about the risk behavior of their male sexual partners who may serve as a “bridge” for HIV transmission into the general population. As part of an online survey examining the sexual risk behavior of Latino men who have sex with men (N = 1,026), we identified 44 (4%) participants who reported having had sex with a transgender partner. Compared with a randomly selected sub-sample of 200 men who did not report sex with a transgender person, sexual partners of transgender persons were almost three times more likely to have had unprotected sexual intercourse in the last three months. In addition, men who had sex with transgender persons were more likely to be HIV-positive; married, separated, or divorced; identify as bisexual or straight; have sex with women; and live in rural or small town communities. Regression analysis revealed that community size, sexual compulsivity, and having had a transgender partner were independent predictors of unprotected sex. Among Latino men who have sex with men, men with a history of sex with a transgender person appear more likely to be sexually compulsive and at greater risk for HIV and other sexually transmitted infections. These men may, therefore, also serve as a “bridge” for HIV transmission to (as opposed to from) the transgender population.
Questions of Complexity and Scale in Explanations for Cultural Transitions in the Pleistocene: A Case Study from the Early Upper Paleolithic

Matching scales of observation and explanation is an essential challenge for archaeology, Paleolithic archaeology in particular. This paper presents a case study from the Early Upper Paleolithic (EUP) in the Eastern Mediterranean to illustrate some of the scalar issues in explaining transitions in the Pleistocene. The cultural sequence at Ucagizli Cave I documents both continuity and change in a range of behaviors over approximately 12 ky. The sequence spans the transition from one EUP cultural unit, the Initial Upper Paleolithic (IUP) to another one, the Ahmarian. There is evidence for changes in lithic technology and retouched tool forms, human diets, and the role of the site within a regional land use system, but few if any of these changes are closely timed with the shift from one archaeological “culture” to another. In this particular case, local and regional transitions seem to be largely unconnected. However, considering the local situations allows a more precise focus on what the broader cultural transition represents and how it might be studied.
Failure of neuromuscular blockade reversal after rocuronium in a patient who received oral neomycin

Because the aminoglycoside antibiotics and nondepolarizing muscle relaxants have interactions that vary, it is necessary to update the potential for such interactions when new drugs are introduced clinically. Rocuronium is a newly released steroidal nondepolarizing muscle relaxant with an intermediate duration of action. The following report is the first description of prolonged neuromuscular blockage after rocuronium in a patient who had received oral neomycin in anticipation of open bowel resection. A 71-yr-old woman with a two week history of bleeding pr was scheduled for exploratory laparotomy and right hemicolectomy. She received two standard bowel preparations consisting of oral erythromycin and neomycin over a two day period. Rocuronium was used to facilitate tracheal intubation and maintain muscle relaxation during a two hour operation. Despite clinical appearance of reversal of neuromuscular blockade after neostigmine and glycopyrolate, the patient complained of dyspnoea and weakness upon tracheal extubation and required reintubation twice. The reason for prolonged muscle relaxation was thought to be secondary to a rocuronium and neomycin interaction. Rocuronium, a new nondepolarizing muscle relaxant, has potential interactions with other drugs including the aminoglycoside antibiotics. This clinical report describes the failure of neuromuscular blockade reversal in a patient who received oral neomycin in anticipation of open bowel resection.
An effective optimization-based algorithm for job shop scheduling with fixed-size transfer lots

Abstract Effective scheduling of production lots is of great importance for manufacturing medium to high-volume products that require significant setup times. Compared to traditional entire-lot production, lot splitting techniques divide a production lot into multiple smaller sublots so that each sublot can be “transferred” from one stage of operation to the next as soon as it has been completed. “Transfer lots,” therefore, significantly reduce lead times and lower work-in-process (WIP) inventory. The mathematical modeling, analysis, and control of transfer lots, however, is extremely difficult. This paper presents a novel integer programming formulation with separable structure for scheduling job shops with fixed-size transfer lots. A solution methodology based on a synergistic combination of Lagrangian relaxation, backward dynamic programming (BDP), and heuristics is developed. Through explicit modeling of lot dynamics, transfer lots are handled on standard machines, machines with setups, and machines requiring all transfer lots within a production lot to be processed simultaneously. With “substates” and the derivation of DP functional equations considering transfer lot dynamics, the standard BDP is extended to solve the lot-level subproblems. The recently developed “time step reduction technique” is also used for increased efficiency. It implicitly establishes two time scales to reduce computational requirements without much loss of modeling accuracy and scheduling performance, thus enabling resolution of long-horizon problems within controllable computational requirements. The method has been implemented using object-oriented programming language C++, and numerical tests show that high-quality schedules involving transfer lots are efficiently generated to achieve on-time delivery of products with low WIP inventory.
Functional analysis of mammalian members of the transforming growth factor-β superfamily

Analysis of growth factor function has come from studies both in vitro and in vivo. However, the generation of mice deficient in a specific growth factor via gene targeting (for example, "knockout") strategies in embryonic stem (ES) cells will often evaluate the essential roles of the protein in vivo and, in many cases, discover new functions. In this review, studies to date are discussed on the generation and analysis of mice deficient in members of the transforming growth factor (TGF-beta) superfamily. Among the genes targeted via ES cell strategies are the TGF-beta1, Mullerian-inhibiting substance (MIS), inhibin alpha, activin betaA, and activin betaB genes. In addition, the mouse short ear and brachypodism mutants and insertional mutant 413-d have been identified as mutations in the BMP-5, GDF-5, and nodal loci, respectively. These studies have led to critical insights into the functions of these gene products and have further emphasized the importance of members of the TGF-beta superfamily in mammalian development, reproduction, and oncogenesis.
Tetragonal magnetic states of Fe and Mn

Tetragonal states of Fe and Mn have been studied by finding total energies at constant volume $V$ as a function of $c/a$ with the full-potential linearized-augmented-plane-wave method. Minima in ${E}_{V}(c/a)$ give the $c/a$ values of equilibrium states. Both Fe and Mn are shown to have stable and metastable equilibrium states in each of several magnetic phases. The calculations on Fe show an antiferromagnetic (AF) face-centered-tetragonal (fct) equilibrium state at $c/a=1.08,$ which has been stabilized as a strained epitaxial film. The calculations on Mn show an AF equilibrium state at $c/a=0.96$ (fct), in agreement with the measured value of $c/a=0.95$ on a crystal stabilized by alloying. Also AF bcc Mn is shown to be unstable, but an equilibrium AF state at $c/a=0.60$ exists.
On ambidextrousness, or, What is an innovative action?

In his article "On the Ambiguity of Ambidextrousness, or, What is an Innovative Action?" Brett Neilson explores the significance of the fact that the technical equality of the hands is realized above all in the act of manual labor, revisiting an influential essay by Robert Hertz, a student of Emile Durkheim and associate of Marcel Mauss, published in 1909 and entitled "The Pre-Eminence of the Right Hand." In his text, Hertz argued that the basic spatial distinction between the left and right hand acquires the polarity of a social hierarchy owing not to the physiology or psychology of motor asymmetry but owing to a cultural choice rooted in experiences of the sacred and profane. With reference to Marx's discussion of productive and non-productive labor in his Grundrisse, the world-making capacity of the hands is analyzed vis-a-vis the productive regime of capital and its increasing subordination of human motor control to machines. Finally, following Paolo Virno's observations regarding immaterial labor and cognitive capitalism in his The Grammar of the Multitude, Neilson discusses what relevance (if any) the cultural distinction — and ambiguity — between the hands holds in the age of information. Brett Neilson, "On the Ambiguity of Ambidextrousness, or, What is an Innovative Action?" page 2 of 8 CLCWeb: Comparative Literature and Culture 12.4 (2010): Thematic Issue Ambiguity in Culture and Literature. Ed. Paolo Bartoloni and Anthony Stephens
U(VI) and Sr(II) batch sorption and diffusion kinetics into mesoporous silica (MCM-41)

Abstract Important reactive phenomena that affect the transport and fate of a radioactive material such as uranium (U) and strontium (Sr) in the environment occur at the mineral–water interface, particularly in mesoporous materials which are ubiquitous in surface and near-surface environments, and typically dominate the reactive surface area of geologic media. Ion sorption and physical bonding forces (including electrostatic forces) can be significantly modified within these confined pore spaces, leading to preferential enrichment of trace elements in mesopores. Pore space confinement may also lead to kinetic restraints on thermodynamically favorable sorption/desorption, precipitation/dissolution, and redox reactions, due to slow migration of metals out of mesopores, chemical gradients within the pore space, or steric constraints for inward migration of larger molecules. Using a combination of benchtop sorption experiments, TEM, and synchrotron-based X-ray absorption spectroscopy, U(VI) and Sr(II) uptake on mesoporous silica (MCM-41) with a 4.67 nm pore diameter was measured in batch conditions at pH 4.0 and 9.8 as a function of time and metal speciation. Uptake of U was determined for U-hydrolysis, U–CO 3 , and U–CO 3 –Ca aqueous species. This suite of techniques enabled determination of the rate of metal sorption and precipitation in the pore spaces, and identification of the reaction products. Our results indicate that Sr and U (at less than 10 μM total U) rapidly diffuse into MCM-41. U at a higher concentration than 10 μM also rapidly diffuses in, but the higher pore volume U concentration eventually leads to polymerization and precipitation of nano-U-bearing phases. The steady state U sorption maximum after 48 h of exposure to MCM-41 prior to precipitation was dependent on the size and charge of the dominant U species in solution, where the trend is: UO 2 (OH) 3 − > UO 2 + 2 > UO 2 (CO 3 ) 3 − 4 ≈ CaUO 2 (CO 3 ) 3 − 2 . Precipitation of a U-bearing phase within the silica pore spaces occurred only after a threshold time point and indicated that U uptake was both thermodynamically and kinetically controlled. Initial diffusion and adsorption were controlled by aqueous speciation and precipitation was controlled by the buildup of sorption species that subsequently created a bottleneck effect near pore openings. Acidic solutions wee more efficient at extracting U than carbonate solutions once the U has diffused into the mesopore region, and this may explain frequent observations of this behavior in extractions of natural sediments. A nitric acid wash was not completely effective at desorbing U and Sr from the mesoporous silica, where there was 5% (initial pH 4.0) and 20% (pH 9.8) remaining even after 500 h of exposure to the nitric acid wash. The results show that U and Sr diffusion and sorption into mesopores result in a recalcitrant pool of ions that are sequestered in deep internal pore spaces, and this may have significant impacts on attempts to clean up contaminated soils and sediments.
Effective material properties extraction method for an asymmetric metamaterial with uneven distances to two measurement ports

This paper derives the new equations for the full extraction method in retrieving effective refractive indices, impedances, and material properties, such as permittivity (e) and permeability (μ), of an asymmetric metamaterial, meaning that the metamaterial slab is asymmetric along the wave propagation direction, or the slab is not mounted exactly in the middle of two measurement ports. Traditionally, the well-known methods proposed by D.R. Smith and Kong assume the equal distances from the measurement ports to the metamaterial slab surfaces. However, it may create problems in real measurements to place the slab exactly in the middle position between two measurement ports. As a result, the retrieved effective material properties may be discontinuous. In this paper, we derive the new equations to solve the problem and successfully retrieve the continuous material properties of the metamaterial slab.
Light quenching and fluorescence depolarization of rhodamine B and applications of this phenomenon to biophysics

The fluorescence intensity of rhodamine B (RhB) was found to display a sublinear dependence on incident power when excited with the focused output of a cavity-dumped dye laser. This effect was found to be proportional to the amplitude of the emission spectrum at the incident wavelength and to be associated with a decrease in the time-zero anisotropy of RhB. The absence of changes in the intensity decay law or rotational correlation time indicates the absence of photochemical processes. These results are consistent with "light quenching" of RhB due to stimulated emission. In viscous solution the extent of depolarization of the emission was found to be in agreement with theoretical expressions which account for photoselective light quenching and for spatial inhomogeneities in the incident laser beam. The phenomenon of light quenching has numerous potential applications in biophysics, such as studies of the orientation and dynamics of fluorescent macromolecules.
Zooplankton as an index of water exchange between Bikini Lagoon and the open sea

The zooplankton (small floating animals) are useful indicators of water currents in the area where they live. Of the holoplanktonic (permanently planktonic) forms found in Bikini Lagoon, 90 per cent or more occur also in the surrounding open sea. The lagoon plankton, however, is characterized by (1) a number of endemic species not found outside the lagoon except where washed out by outflowing currents, and (2) a concentration within the lagoon of many forms that occur normally also in the outside surface waters. Both of these features are dependent upon the degree of dispersal of the plankton and are therefore directly correlated with the semiclosed circulation which the lagoon imposes upon the water that flows in over the eastern and northeastern reefs. A study of the vertical distribution and diurnal vertical migration of the endemic copepod Undinula vulgaris, and of the general plankton, reveals that much of the lagoon plankton lives mainly in the deeper slowly (0.1 knot) eastward-moving counter current which as a water mass represents 70 to 90 per cent of the living space in the lagoon. Even during the night when much of the plankton migrates towards the surface into the faster (0.3 knot) westward-moving water, about two-thirds of the plankton still remains within the deeper counter current. Much of the oceanic plankton swept into the lagoon thrives there and becomes concentrated so that the average concentration per cubic meter of water of the eleven most common animal groups is about four times higher than in the outside north-eastern area, and twice higher than the outside western-southern area of principal outflow. The increased concentration found in the outside water to the west and south indicates an outwash from the lagoon in that area and is shown especially by such forms as Undinula vulgaris and Tretomphalus planus (foraminifer), which occur abundantly in the lagoon, but were not found in the area immediately to the east and north of the atoll. The restricted water flow within the lagoon is biologically important in conserving also the transitory planktonic larval stages of lagoon and reef fishes and bottom-living animals. The presence of Copilia mirabilis (copepod) mainly in the southern half of the lagoon and outside around the southern and south-eastern periphery of the atoll suggests a slow flow of southern water into the lagoon between Enyu and Bikini Islands and through the eastern part of Enyu Channel.
Kuhn's “The Logic of Social Systems”: The rational first approximation as social science

Policy analysis needs to be underpinned by a theoretical social science that offers both a comprehensive vocabulary for social analysis and a base line or first approximation in terms of which, or against which, both scientific and normative analysis may proceed. It seems to me that Alfred Kuhn's The Logic of Social Systems offers such point of departure. In order to use Kuhn one needs neither to accept his mechanistic world outlook, or the details of his highly developed definitional exploration. But the spirit of his analysis offers a coherent model, and incorporates a great deal that both the general population and the scientific fraternity know of man. As such it is on the one hand a least common denominator, and on the other a complex universe of discourse worth learning by all.
Monitoring urban impacts on suspended sediment, trace element, and nutrient fluxes within the City of Atlanta, Georgia, USA : program design, methodological considerations, and initial results

Atlanta, Georgia (City of Atlanta, COA), is one of the most rapidly growing urban areas in the US. Beginning in 2003, the US Geological Survey established a long-term water-quantity/quality monitoring network for the COA. The results obtained during the first 2 years have provided insights into the requirements needed to determine the extent of urban impacts on water quality, especially in terms of estimating the annual fluxes of suspended sediment, trace/major elements, and nutrients. During 2004/2005, suspended sediment fluxes from the City of Atlanta (COA) amounted to about 150 000 t year−1; ≥ 94% of the transport occurred in conjunction with storm-flow, which also accounted for ≥ 65% of the annual discharge. Typically, storm-flow averaged ≤20% of the year. Normally, annual suspended sediment fluxes are determined by summing daily loads based on a single calculation step using mean-daily discharge and a single rating curve-derived suspended sediment concentration. Due to the small and ‘flashy’ nature of the COAs streams, this approach could produce underestimates ranging from 25% to 64%. Accurate estimates ( ± 15%) require calculation time-steps as short as every 2–3 h. Based on annual median base-flow/storm-flow chemical concentrations, the annual fluxes of ≥ 75% of trace elements (e.g. Cu, Pb, Zn), major elements (e.g. Fe, Al), and total P occur in association with suspended sediment; in turn, ≥ 90% of the transport of these constituents occur in conjunction with storm-flow. As such, base-flow sediment-associated and dissolved contributions represent relatively insignificant portions of the total annual load. An exception is total N, whose sediment-associated fluxes range from 50% to 60%; even so, storm-related transport typically exceeds 80%. Hence, in urban environments, non-point-sources appear to be the dominant contributors to the fluxes of these constituents. Published in 2007by John Wiley & Sons, Ltd.
Concurrent Token Production in Rats

The current study assessed whether the generalized matching law would provide an accurate description of behavior maintained by token reinforcement. A dependent-concurrent random interval 15 s schedule of token production maintained lever pressing in rats. Following delivery, each token could be immediately exchanged for sweetened condensed milk. In Experiment 1, the token ratio was either 1:3 or 1:9, depending upon condition, and the location of the rich schedule varied randomly across daily sessions. In Experiment 2, the token ratio varied randomly within each session (1:9, 1:6, 1:3, 1:1, 3:1, 6:1, and 9:1). Overall, the generalized matching law provided a good description of the data, revealing a high degree of undermatching. In Experiment 2, two of three rats tended to return to the just-productive lever following token delivery. The third subject showed this pattern only following left-token deliveries. Overall, the effects of token reinforcers on choice were similar to those observed with other reinforcers.
Hadamard and Schwarz Type Theorems and Optimal Recovery in Spaces of Analytic Functions

We prove a general theorem which gives a necessary condition of extremum in the dual optimal recovery problem in terms of inclusion in certain annihilators. Applications of this theorem yield Hadamard and Schwarz type results. We also construct related optimal recovery methods.
Impact of Regurgitant Orifice Height for Mechanism of Aortic Regurgitation

A classification of aortic regurgitation (AR) by transesophageal echocardiography (TEE) has been considered a critical pre-operative assessment, particularly for valve repair operations [(1)][1]. This study aimed to evaluate the mechanism of isolated AR by quantitative analysis of aortic valve
Plasma Synthesis of Nitrogen Clusters on Carbon Nanotube Sheets

The radio frequency plasma synthesis of nitrogen clusters stabilized on carbon nanotube sheets has been demonstrated under various conditions. Characterization of the samples produced has been carried out using micro-Raman and attenuated total reflectance-Fourier transform infrared spectroscopy. Initial investigations of the sample morphologies and compositions have also been performed using scanning electron microscopy combined with energy-dispersive x-ray analysis and transmission electron microscopy. The spectroscopic results, together with density functional theory calculations, suggest that a linear chain nitrogen cluster is formed under the plasma conditions employed and is stabilized most likely inside the walls of the carbon nanotubes that are used as substrates during the synthesis.
Strong-Field Atomic Phase Matching

We interpret a learning-control experiment with the goal of optimizing multiphoton population transfer in atomic sodium in the strong-field limit. Despite multiple experimental constraints, a learning algorithm discovers optimal pulses that can be understood in terms of a simple dynamic picture of the atom-field interaction. We show that the shaped pulses counteract the dynamic Stark-induced stimulated emission that would otherwise impede the efficient use of a $\ensuremath{\pi}$ pulse to invert a multiphoton transition.
License as Leverage: Mandating Treatment for Professionals

Mandating professionals with mental disorder to adhere to psychological or psychiatric treatment in order to maintain their professional license frequently occurs and is rarely controversial. We survey current practices in using a professional license as "leverage" to assure adherence to treatment, and compare mandated treatment for professionals with other, more controversial forms of mandated treatment. Our analysis raises two questions. First, if the same level of high quality treatment now available to licensed professionals with mental or addictive disorders were made readily available to others with these disorders, would the positive outcomes experienced by the former also be experienced by the latter? Second, if the same intensive level of monitoring were applied to others as is now applied to licensed professionals, would rates of treatment adherence between the two groups tend to converge?
Drug Treatment of HIV-Related Opportunistic Infections

The AIDS epidemic has led to the emergence of several disease entities which in the pre-AIDS era were rare or seemingly innocuous. Experience of treating these diseases varies. In some instances, such as Pneumocystis carinii pneumonia, there is an abundance of published literature to direct our course of action. However, for many of these newly recognised diseases our treatment experience is limited. Furthermore, in many instances, well controlled trials evaluating treatment modalities in the AIDS population are lacking. We have identified 13 disease entities (P. carinii pneumonia, toxoplasmosis, cryptococcosis, histoplasmosis, Mycobacterium tuberculosis, Mycobacterium avium complex, cytomegalovirus, coccidioidomycosis, isosporiasis, candidosis, Kaposi's sarcoma, herpes simplex virus, and varicella zoster virus) and have reviewed the current literature with regard to their treatment.
Gender differences in the distribution of cocaine and heroin in Central Harlem.

Abstract Objective: This article investigates the extent to which users of crack, powder cocaine and heroin in Central Harlem participate in various roles involved in distributing these drugs, examining gender differences among distribution roles. Methods: Several strategies were combined to acquire a sample of 655 hard drug users and sellers who self-reported demographics, drug use and other factors in a face-to-face interview. Chi-square analyses were used to examine factors associated with having drug distribution roles. Results: More than two-fifths ( N = 269) of all respondents self-reported participation in at least one current distribution role. The most common roles were acting as a middleman, steering buyers, holding drugs or money, and transporting drugs. Distributors were more likely to have HIV, previous drug treatments, and less education, employment or housing, but had higher incomes than users. A higher proportion of women reported drug distribution roles, but among distributors, men were twice as likely women to be direct sellers and transporters of drugs, and to perform more distribution roles. Conclusions: Gender contrasts support previous research indicating male dominance of drug distribution roles. Previous studies may underestimate women's participation in distribution roles. Drug treatment programs are encouraged to augment existing relapse prevention activities with distribution prevention efforts.
Breakup of Temperature Inversions in Deep Mountain Valleys: Part II. Thermodynamic Model

Abstract A thermodynamic model is developed to simulate the evolution of vertical temperature structure during the breakup of nocturnal temperature inversions in mountain valleys. The primary inputs to the model are the valley floor width, sidewall inclination angles, characteristics of the valley inversion at sunrise, and an estimate of sensible heat flux obtained from solar radiation calculations. The outputs, obtained by a numerical integration of the model equations, are the time-dependent height of a convective boundary layer that grows upward from the valley floor after sunrise, the height of the inversion top, and vertical potential temperature profiles of the valley atmosphere. The model can simulate the three patterns of temperature structure evolution observed in deep valleys of western Colorado. The well-known inversion breakup over flat terrain is a special case of the model, for which valley floor width becomes infinite. The characteristics of the model equations are investigated for several ...
Environmental factors influencing distribution and morphology of rhodoliths in Bahia Concepcion, B.C.S., Mexico

Abstract Aerial and SCUBA diving observations revealed numerous, dense concentrations of free living, branched, nongeniculate coralline algae (rhodoliths) at depths of 3–12 m in Bahia Concepcion, B.C.S., Mexico. Plants were up to 10 cm in size, and commonly occurred at high densities forming a near continuous layer overlying a mixture of calcareous fragments and sediment. In contrast to other geographic regions, rhodolith shape remained spherical along depth-related gradients of water motion and sedimentation. Branch density and size, however, generally decreased with increasing depth. Surveys, as well as transplant and movement experiments, suggested that broad scale (east vs. west shore) and depth distribution of rhodolith beds within the bay are controlled by water motion and sedimentation. Additional experimental and taxonomic studies are needed to understand the smaller scale distribution patterns, and among and within bed variation in plant size and branch density. Such studies will allow a more rigorous interpretation of paleoenvironments based on the morphology of fossil rhodoliths.
The interstellar material in front of Chi Ophiuchi. I - Optical observations

Optical observations of the interstellar material in front of Chi Oph are discussed. The main interstellar cloud is made up of several regions with velocities between -6 and -12 km/s (heliocentric). Both CH and CH(+) are found within this feature, but with central velocities which differ by 2 km/s. Another cloud, with a velocity of -26 km/s, contains relatively strong Ca(+) lines. It has a ratio between Ca(+) and Na(0) column densities that is appropriate for 'high-velocity' clouds. Calcium, iron, and sodium column densities are used to estimate an average electron density for the line of sight, as well as for each cloud. The abundances of CH and CH(+), and the absence of CN, are analyzed in terms of current theories about their origin.
The Effect of Financial Contingencies on Golf Performance

The current study investigated the effects of monetary contingencies on the performance of experienced golfers in the natural setting. Utilizing a multi-element design reversal design counter balanced across tasks, investigators exposed participants to contingencies involving the ability to earn or lose money, based on performance. Results yielded a significant detriment to performance when monetary contingencies were implemented for non-professional golfers. Contrasting results in the performance of one professional golfer yielded no significant difference in performance across conditions. Results suggest that monetary wagers affect performance, and furthermore, that performance of amateur players may be more easily influenced by such contingencies.
Myocardial tissue characterization by autocorrelation of two-dimensional ultrasonic backscatter.

To evaluate a novel method for determining the spatial distribution of echocardiographic information based on the two-dimensional. autocorrelation function, echocardiographic images were obtained from specific regions of interest from 10 healthy volunteers, seven patients with genetically defined hypertrophy cardiomyopathy, and nine patients with pressure-overload hypertrophy. The wavelength of distinct peaks from the two-dimensional autocorrelation of the images was compared between groups of patients and demonstrated a significant decrease, in the mean length scale associated with distinct secondary correlation peaks in patients with hypertrophy cardiomyopathy or pressure-overload hypertrophy compared with healthy volunteers ( p = 0.0009). With a discriminating wavelength of 3.3 mm, the sensitivity of this technique for detecting abnormal myocardium was 84% with a specificity of 89%. This study suggests that ultrasonic tissue characterization based on the two-dimensional autocorrelation function may have potential for distinguishing normal from abnormal myocardium and provides a rationale for textural approaches to ultrasonic tissue characterization.
Does the built environment matter for physical activity

There has been a dramatic increase in the number of studies that correlate aspects of the built environment with physical activity. Several publications have summarized the state of the field and have made recommendations on how to move the field forward. This paper describes some of the recommendations and reports on recent progress that has been made on them. Specific issues that are addressed are causality, perceived versus objective environmental measures, definitions of a neighborhood, use of audit instruments, and cost-benefit studies.
Dark matter from hidden forces

We examine the possibility that dark matter may be the manifestation of dark forces of a hidden sector, i.e. ``$\text{dark}\text{ }\text{force}=\text{dark}\text{ }\text{matter}$.'' As an illustrative and minimal example we consider the hidden $\mathrm{SU}{(2)}_{h}\ifmmode\times\else\texttimes\fi{}\mathrm{U}{(1)}_{h}$ gauge group. The hidden dynamics is indirectly coupled to the Standard Model (SM) through kinetic mixing of $\mathrm{U}(1{)}_{h}$ with the $\mathrm{U}{(1)}_{Y}$ of hypercharge. We assume a hidden symmetry-breaking pattern analogous to that of the SM electroweak symmetry, augmented with an extra scalar that allows both the ``hidden $Z$ boson'' ${Z}_{h}$ and the ``hidden photon'' ${\ensuremath{\gamma}}_{h}$ to be massive. The ``hidden $W$'' bosons ${W}_{h}^{\ifmmode\pm\else\textpm\fi{}}$ are dark matter in this scenario. This generic setup can readily accommodate potential direct detection signals for light dark matter. For some choices of parameters, the model can lead to signals both in ``dark matter beam'' experiments, from ${Z}_{h}\ensuremath{\rightarrow}{W}_{h}{W}_{h}$, as well as in experiments that look for visible signals of dark photons, mediated by ${\ensuremath{\gamma}}_{h}$. Other possible phenomenological consequences are also briefly discussed.
Reversible Deficit in Haptic Delay Tasks from Cooling Prefrontal Cortex

The main purpose of this study was to explore the role of dorsolateral prefrontal cortex in skilled and sequential haptic performance. Monkeys were trained to perform a delayed matching-to-sample task that required the memorization of three-dimensional objects perceived either by palpation (haptically) or by sight. At the start of a trial the animal was allowed to touch or view an object, the sample; after a period of delay, during which the object remained out of touch and out of sight, the animal was presented with two side-by-side objects--one of them the sample--for either tactile or visual recognition, and the choice of the sample (correct match) was rewarded. Three variants of the task were used: (1) visual sample, haptic match; (2) haptic sample, visual match; and (3) haptic sample, haptic match. The temporary bilateral cooling of dorsolateral prefrontal cortex to 15 degrees C induced a reversible deficit in performance of all three tasks. Cooling to the same degree a portion of posterior parietal cortex of equivalent size did not significantly alter either performance or reaction time. These findings indicate that the functional integrity of the dorsolateral prefrontal cortex is important for performance of sequential behavior dependent on haptic skill. Further, the results suggest that the role of this cortex in active memory, already well documented for spatially and nonspatially defined visual information, extends also to tactile information and associated motor acts.
The Kirby Canyon Conservation Agreement: A Model for the Resolution of Land-use Conflicts Involving Threatened Invertebrates

The Kirby Canyon Conservation Agreement was designed to provide protection of the Bay Checkerspot Butterfly ( Euphydryas editha bayensis ) while allowing development of an extensive solid-waste landfill in the habitat of that threatened subspecies. Elements of the programme include 1) biological research; 2) habitat acquisition; 3) habitat management; 4) restoration and revegetation activities; and 5) off-site recovery, including reintroduc-tion of the Butterfly into an unoccupied suitable habitat. The high likelihood of success of this agreement reflects the availability of detailed life-history information, the known ecological characteristics of the Butterfly, and the geographic scale of the proposed development. This agreement should provide a useful model for the resolution of potential conflicts between endangered invertebrates and resource development in urban corridors elsewhere.
Solar longitude dependence of some characteristics of type III radio bursts from metric to hectometric wavelengths

Using the observed data for metric and hectometric type III radio bursts, the dependence of burst characteristics on the solar longitude has been examined over a wide frequency range. It is found that there exists and east-west asymmetry for the extension of metric type III bursts into the hectometric wavelength range. In particular, hectometric bursts are rarely observed for solar flares associated with metric bursts east of 60 E solar longitude. Furthermore, for east longitudes, the low-frequency radio observations show a large dispersion in drift time interval.
Marketless Trading in Our Time

The late Hungarian-American economic historian Karl Polanyi formulated the view that "Economic activity ... is not channeled through organized markets to any considerable extent in the ancient world')." What he meant by a market is an institution of exchange in which the prices are set by supply and demand2). Assyriologists have largely ignored Polanyi's market arguments while accepting that many of the archival texts we have do reflect redistribution systems that are not much affected by markets. Though the Assyriologist A. L. Oppenheim for a time allied himself with Polanyi's views, he appears later to have distanced himself from them. In his 1970 paper for the Fifth Congress of Economic History in Moscow he omitted from his rather extensive bibliography Polanyi's 1947 paper, "Marketless Trading in Hammurabi's Time3)"-from which I take my title-and also Oppenheim's own paper in the same volume, and he seemed to feel that market mechanisms were important in Mesopotamia and were getting more important in later periods like the Neo-Babylonian4). Since then, K.
Large Aperture O I 6300 Å Observations of Comet Hyakutake: Implications for the Photochemistry of OH and O I Production in Comet Hale-Bopp

In previous work (Morgenthaler et al. and Glinski et al.), we proposed a revision to the standard OH photochemistry of van Dishoeck & Dalgarno in order to explain the anomalously bright [O I] 6300 A emission observed by several instruments in comet C/1995 O1 (Hale-Bopp). In order to test the validity of revisions to the OH photochemistry, we present wide-field Fabry-Perot [O I] 6300 A observations of comet C/1996 B2 (Hyakutake) and review similar observations recorded for 1P/Halley and 1989 c1 (Austin). Conventional long-slit spectroscopic observations of several comets in [O I] are also reviewed. The bulk of the evidence suggests that the OH photochemical rates of van Dishoeck & Dalgarno are, on the whole, correct and that the bright [O I] emission observed in Hale-Bopp, particularly at cometocentric distances beyond ~3 × 104 km, was unique to that comet, or possibly any comet with such a large production rate.
An abstinence syndrome following chronic administration of delta-9-tetrahydrocannabinol in rhesus monkeys

Chaired, chronically catheterized rhesus monkeys were administered IV delta-9-tetrahydrocannabinol (THC), 0.5 mg/kg every 6 h for 3 weeks. Following the first THC injection, the animals appeared heavy-lidded, immobile, and unresponsive to observation. Tolerance developed to these behaviors during the 3 weeks of THC administration, although the animals remained subdued compared to baseline. Following discontinuation of THC, animals showed an increase in gross movement, eye contact, and tooth baring of greater frequency and/or duration than observed before THC. This presumably represents a cannabis abstinence syndrome.
Widespread Distribution of a 5-deazaflavin Cofactor in Actinomyces and Related Bacteria

Summary Extracts of a variety of bacteria were examined spectrofluorimetrically for the presence of 5-deazaflavins. The effects of pH and reduction on both excitation and emission spectra were examined to prove the identity of the fluorescent compounds. All of the 9 strains of Streptomyces, Mycobacterium tuberculosis and Nocardia aurantia had significant levels of this class of compounds; those containing higher levels had approximately 1 % of that found in methanogenic bacteria. Other eubacteria, a Haloarcula species and two yeasts did not contain any detectable 5-deazaflavin
Digital Computer Techniques for Determining Circuit Behavior in a Pulsed Nuclear Environment

Two digital computer circuit analysis programs which predict circuit response in a pulsed nuclear radiation environment are presented. One program requires that linear direct current equations be written manually and then programmed for computer solution. The other program generates the equations from topological circuit information and then solves the equations during the radiation burst automatically. Predictions generated by the automated program on four different circuits are verified experimentally.
Synthesis and structure of [1,2-bis(1-indenyl)benzene]titanium and zirconium dichlorides

Abstract The palladium-catalyzed coupling of 1,2-diiodobenzene with indenylzinc complexes obtained from indene, 4-methylindene, 4,7-dimethylindene and hydrindancene gave 1,2-bis(1-indenyl)benzenes in 29–45% yield. New phenyl-bridged ansa-bis(indenyl)titanium and -zirconium dichlorides were obtained from these ligands in good yield either by addition of TiCl3 or ZrCl4 to their lithium salts (61–92% yield) or by addition of Zr(NMe2)4 to the neutral ligands (59–67%). In each case the zirconium tetraamide metalation gave very high dl-selectivity. The n-BuLi/ZrCl4 metalation of the phenyl-bridged unsubstituted indene gave a 3:2 ratio of dl- to meso- while placing substituents at the 4,7- and 5,6-positions led to 10:1 selectivity in favor of the dl-isomer. The n-BuLi/TiCl3 metalation gave between 1:1 and 4:1 selectivity. The solid state structure of [1,2-bis(1-indenyl)benzene]dichlorozirconium (dl-6a) was obtained by X-ray analysis.
Self-Welded Metal-Catalyzed Carbon Nanotube Piezoresistors with Very Large Longitudinal Piezoresistivity of ~ 4×10 -8 Pa -1

Self-welded double-wall and multi-wall carbon nanotube (DWCNT and MWCNT) bridges were used for the first time as nano-scale piezoresistors to monitor vibration and deformation of silicon cantilever beams. The CNTs were grown using low-pressure metal-catalyzed chemical vapor deposition technique between silicon-on-insulator posts situated over cantilever beams such that when the beams were deformed, CNTs were axially strained. Telescoping of inner CNT cylinders occurring under these axial strains changed the CNTs resistance. The CNT-post weld strength, as measured using atomic force microscope, was larger than 100 nN/CNT and their full-scale resistance change was larger than 105 Ω. The effective longitudinal piezoresistivity of CNTs was larger than 4×10-8 Pa-1 which is more than 10 times larger than that of Π44 in silicon