cssi/SciSciGPT-SciSciNet huggingface dataset:
Orientation and Speed of the Parsec-Scale Jet in NGC 4261 (3C 270)

NGC 4261 (3C 270) is an elliptical galaxy containing a 300 pc–scale nuclear disk of gas and dust imaged by the Hubble Space Telescope (HST), around a central supermassive black hole. Previous VLBI observations of NGC 4261 revealed a gap in emission in the radio counterjet, presumably due to free-free absorption in the inner parsec of the accretion disk. Here we present three 8 GHz VLBA observations of NGC 4261 that allow us to monitor the location and depth of the gap and check for motions in the jet and counterjet. The separation between the brightest peak and the gap is stable, with an upper limit to its motion of 0.01c, supporting the interpretation of the gap as absorption by an accretion disk rather than as an intrinsic jet feature. These observations span a time of order that required for orbiting material in the disk to transit the counterjet, so we are able to search for density changes (clumps) in the disk by monitoring the optical depth of the gap. The optical depth of the gap is stable to within 20% over 5 years at τ = 1.1 ± 0.1, corresponding to an electron density in the disk that is constant to within 10%. We measure an apparent speed in the jet of (0.52 ± 0.07)c. An apparent speed could not be measured for the counterjet because of a lack of identifiable features. From the apparent jet speed and the jet-to-counterjet brightness ratio, we calculate the viewing angle of the jet to be 63° ± 3° and its intrinsic speed to be (0.46 ± 0.02)c. From the inclination and position angles of the parsec-scale radio jet and outer HST disk rotation axis we calculate a difference between the parsec-scale radio jet and outer HST disk rotation axis of 12° ± 2°. Because of its well-defined HST disk and bright parsec-scale radio jet and counterjet, NGC 4261 is ideal for studying the combined disk-jet system, and this is the first case known to us in which both the inclination and position angles of both the disk and jet have been determined.
Relieving frustration: The case of antiferromagnetic Mn 3 molecular triangles

Recently, various triangular [Mn${}^{\mathrm{III}}$]${}_{3}$ molecules have been extensively studied due to the fact that one can modulate the magnitude and the sign of the inter-ion exchange, thereby giving rise to very simple clusters that constitute some of the cleanest and best examples of so-called single-molecule magnets. However, magnetic and electron paramagnetic resonance (EPR) characterizations of low-spin antiferromagnetic [Mn${}^{\mathrm{III}}$]${}_{3}$ complexes have been problematic due to the significant spin frustration that exists for this topology. We show that this frustration is relieved in the highly distorted [NEt${}_{4}$]${}_{3}$Mn${}_{3}$Zn${}_{2}$(salox)${}_{3}$O(N${}_{3}$)${}_{8}$]\ifmmode\cdot\else\textperiodcentered\fi{}MeOH molecule: Susceptibility data suggest a well isolated S = 2 ground state; EPR spectroscopy and high-field torquemetry support this conclusion and further indicate the presence of a very significant zero-field-splitting (zfs) separating the lowest-lying ${m}_{S}$ = \ifmmode\pm\else\textpm\fi{}2 states from the excited levels within the same S = 2 multiplet. Remarkably, this zfs is sufficient to give rise to magnetic bistability, as evidenced through the observation of low-temperature magnetization hysteresis.
Institutional sources of medical school faculty and patterns of personnel flow among medical schools.

PURPOSE To describe patterns of interaction among U.S. medical schools related to faculty production and faculty hiring. METHOD The medical school origins of MD faculty earning degrees between 1980 and 1989 and holding full-time positions in 1995 were used to gauge organizations' tendencies to interact and to identify institutional participants and their roles in reciprocal interactions. Additional data on medical school characteristics were used to characterize faculty suppliers, employers, and interacting organizations. Included in the present study were 19,381 individuals who were active, full-time members in 1995 and who held MD degrees earned between 1980 and 1989 from one of the 125 accredited U.S. medical schools. RESULTS Major research-oriented medical schools were the most active suppliers of faculty to other medical schools. Foremost among these "research" schools was Harvard Medical School, which had nearly 20% of its 1980-1989 graduates widely dispersed among all the medical schools in 1995. Data on reciprocal interactions involving nine or more faculty were used to form empirically based groups of three geographically proximate dyads in North Carolina, Michigan, and Puerto Rico, and one complex cluster of 17 schools. CONCLUSION The findings suggest that medical schools can be grouped and characterized by looking at institutional-level data on faculty production and employment. Research-oriented medical schools have been the major producers of medical school faculty. Recent emphasis on generalist careers may have the unintended consequence of further diminishing the variety of institutional sources of medical school faculty.
Lost and Found in Transnation: Modern Conceptualization of Chinese Rhetoric

Why do the Chinese relate rhetoric only to stylistic devices in writing? This question, which has puzzled scholars for decades, is finally answered. Modern Chinese rhetoric began to form in the late 1800s when Chinese students learned Western rhetoric from their Japanese professors, who translated it into “the study of beautiful prose,” subsequently severing it from oratory. In the early twentieth century, scholars returning from Japan and the US integrated Japanese theories and Anglo-American figures of speech into Chinese literary and literacy traditions despite nativists' protests and appropriated them into a canon of aesthetics only for writing studies.
Redox speciation of plutonium

Knowledge of the oxidation state distribution of plutonium in natural waters is necessary in modeling its behavior in environmental systems. The redox speciation of plutonium is complicated by such effects as hydrolysis, complexation, disproportionation, solubility, and redox interchange reactions. The insolubility of Pu(OH)4 is often the limiting factor of the net solubility of plutonium in oxic natural waters where Pu(V)O 2 + is the most stable oxidation state. Perturbations to the oxidation state speciation due to the complexation chemistry of the different oxidation states of plutonium and to the insolubility of plutonium(IV) in neutral aquatic systems are discussed. The merits and limitations of some chemical separation techniques used to study redox speciation of plutonium are presented, and recommendations made for obtaining reliable oxidation state distribution data.
Teratogenicity of antiepileptic drugs: role of drug metabolism and pharmacogenomics

The approach to clinical decision-making pertaining to the use of antiepileptic drugs (AEDs) during pregnancy has relied on previous accumulated experience and, since the 1990s, on data from pregnancy registries. The limitations of this process are that no information regarding the chemical attributes of the AED under consideration, nor the role of a number of enzyme systems that are known to interact with foreign compounds to modify their potential for harm, are included. The role of the hepatic mixed function oxidase system may be especially important in conferring teratogenic risk. However, systems such as epoxide hydrolase, glutathione reductase, superoxide dismutase and other toxin-scavenging systems may be important modifiers that lower the risk. Knowledge is also accumulating on the interactions of AEDs with molecular targets such as histone deacetylase and peroxisome proliferator-activated receptors that may play important roles in teratogenesis. While our knowledge of these factors are incomplete, progress can be achieved by beginning to include these concepts in our discussion on the topic and by promoting research that may improve our ability to individualize the analysis of risk for a specific patient with regards to specific AEDs.
Does Context Matter? Examining the Mental Health Among Homeless People

While much research has focused on the impact community has on health and wellbeing of domiciled populations, limited research has explored the same for homeless people. Using multivariate models, this research explores what factors are related to depressive symptomatology among homeless people living in two distinctly different communities. Results suggest that context matters, but not for every circumstance examined in these models. While some variables exhibit a consistent relationship with depressive symptoms, the role of social capital is noted as particularly important to lowering symptomatology, yet its impact differs significantly by location.
Regioselective Intermolecular Coupling Reaction of Arylketones and Alkenes Involving C-H Bond Activation Catalyzed by an In-Situ Formed Cationic Ruthenium-Hydride Complex

The cationic ruthenium hydride complex, formed in situ from the treatment of the tetranuclear ruthenium hydride complex {[(PCy3)(CO)RuH]4(μ4-O)(μ3-OH)(μ2-OH)} with HBF4·OEt2, was found to be a highly effective catalyst for the intermolecular coupling reaction of arylketones and 1-alkenes to give the substituted indene and ortho-C−H insertion products. The formation of the indene products resulted from the initial alkene isomerization followed by regioselective ortho-C−H insertion of 2-alkene and dehydrative cyclization. The preliminary mechanistic studies revealed a rapid and reversible ortho-C−H bond activation followed by the rate-limiting C−C bond formation step for the coupling reaction.
Investigating the effect of applied pressure on reactive multilayer foil joining

This paper describes the effect of applied pressure on reactive joining of stainless steel specimens and Al alloy specimens using nanostructured Al/Ni foils and AuSn and AgSn solder layers. For a given material system, higher applied joining pressure enhances the flow of the molten solder and thus improves wetting and bonding. Shear strengths of the reactive joints are shown to increase as the pressure that is applied during joining rises to a critical value. At higher applied pressures joint shear strengths remain relatively constant. The critical applied joining pressure is shown to be dependent on the foil thickness (or total heat of reaction), and the properties of the solder material and components, which determine the duration of melting of the solder and the maximum temperature at the solder/component interface. Longer durations of melting and higher interface temperatures enhance the flow of solder, improve wetting conditions and result in lower critical applied pressures.
The effect of three vehicles on the pH of calcium hydroxide.

Abstract Dry calcium hydroxide powder was mixed with either cresatin, camphorated parachlorophenol, or saline solution to form a paste. The pH of each paste was measured and compared. Cresatin, when used as the mixing vehicle, did not produce or maintain as high a pH as the other two mixing vehicles.
Academic research and teaching productivities: A case study☆

Abstract This paper uses University of Utah data on funded research output, teaching output, faculty, and student enrollment for the academic years 1991–1992 to 1993–1994 for a sample of 31 academic departments to estimate joint-product production functions. It is a micro-micro theory approach. Single equation ordinary least squares (OLS) and simultaneous equations generalized least squares (GLS) by linear structural relations (LISREL) estimating methods are used. Research and teaching productivities are compared to the Schumpeterian hypothesis relating to department size and research productivity. Falling teaching productivity and rising research productivity as faculty size increases are among the results. The time effect on production performance was not significant. Implications for the supply of basic research are discussed. Various hypotheses and implications for social policy are discussed.
Language Repair Strategies in Bilingual Tutoring of Mathematics Word Problems

Abstract: This study explores the language repair strategies (aimed at repairing communication problems) of two bilingual speakers during mathematics word problem tutoring sessions. Bilingual repair was shown to gradually shift from a linguistic to an epistemic focus during problem solving (i.e., communication became more conceptually focused over time). Linguistic repair involved varied translation techniques (literal and free), whereas epistemic repair entailed gradual refinement of specialized mathematical meanings through intralinguistic communicative strategies such as simplified rewording. It is suggested that understanding language repair may help tutors develop more effective dialogic instructional approaches to the teaching of mathematical word problems to English learners.
MAPPING IMAGE DATA TO STEREOTAXIC SPACES : APPLICATIONS TO BRAIN MAPPING

A methodology for spatial normalization of image data is presented. This methodology is based on a map between homologous features of an individual brain and the target brain, which is used to drive a three-dimensional elastic warping transformation. Functional or structural information present in the original, nonnormalized images is preserved during this transformation. In particular, information such as the volume or the total amount of a radioactive agent in any brain region can be calculated directly from the normalized images. Moreover, subtle morphological characteristics of an individual brain are captured by the properties of the spatial transformation applied to that brain. Intersubject or interpopulation comparisons are performed by comparing the corresponding transformations. Hum. Brain Mapping 6:334–338, 1998. © 1998 Wiley-Liss, Inc.
Signaling pathways that control cell migration: models and analysis

Dissecting the intracellular signaling mechanisms that govern the movement of eukaryotic cells presents a major challenge, not only because of the large number of molecular players involved, but even more so because of the dynamic nature of their regulation by both biochemical and mechanical interactions. Computational modeling and analysis have emerged as useful tools for understanding how the physical properties of cells and their microenvironment are coupled with certain biochemical pathways to actuate and control cell motility. In this focused review, we highlight some of the more recent applications of quantitative modeling and analysis in the field of cell migration. Both in modeling and experiment, it has been prudent to follow a reductionist approach in order to characterize what are arguably the principal modules: spatial polarization of signaling pathways, regulation of the actin cytoskeleton, and dynamics of focal adhesions. While it is important that we 'cut our teeth' on these subsystems, focusing on the details of certain aspects while ignoring or coarse-graining others, it is clear that the challenge ahead will be to characterize the couplings between them in an integrated framework.
Solvatochromism of the Excitation and Emission Spectra of 7-Aminoactinomycin D: Implications for Drug Recognition of DNA Secondary Structures

The antitumor antibiotic 7-aminoactinomycin D has been previously demonstrated to bind and stabilize transient hairpin structures formed by single-stranded DNA. Those experiments suggested that DNA secondary structures are viable targets for development of novel antitumor or antiviral compounds. Interestingly, when 7-aminoactinomycin D binds to hairpins formed by selected single-stranded DNAs having a high affinity for the drug, the fluorescence quantum yield, average fluorescence lifetime, excitation wavelengths, and emission wavelengths for the drug are significantly different from those observed when it is free in solution or bound to duplex, B-form DNA. This suggests a unique physical chemical environment within certain DNA hairpins that is specifically recognized by the drug. To understand the environmental contribution to the fluorescence properties of the bound drug, we used solvatochromism techniques, whereby 7-aminoactinomycin D fluorescence properties were determined in 20 solvents with known po...
An Agenda- and Justification-Based Framework for Discovery Systems

We propose and evaluate an agenda- and justification-based architecture for discovery systems that selects the next tasks to perform, as well as heuristics for use in discovery systems. This framework has many desirable properties: (1) it selects its own tasks to perform based upon how plausible they are judged to be; (2) it facilitates the encoding of general discovery strategies using a variety of background knowledge; and (3) it tailors its behavior toward a user’s interests. Many experiments with a prototype discovery program called HAMB demonstrate that both reasons and estimates of interestingness contribute to performance in the domains of protein crystallization and patient rehabilitation data. The program’s heuristics provide good initial solutions to problems encountered when implementing fully autonomous discovery systems.
Interactions of gaseous air pollutants with egg lecithin and phosphatidyl ethanolamine monomolecular films

Abstract The interaction of egg lecithin and phosphatidyl ethanolamine monomolecular films with nitrogen dioxide containing atmospheres was studied. The extent of interaction of nitrogen dioxide with the phospholipids studied increased with increasing unsaturation of the phospholipid and with decreasing initial surface pressure of the film. Nitrogen dioxide, in both the gas phase above the film and liquid phase below the film, was found to interact with the phospholipids.
The crystal and molecular structure of tetrakis(thioacetamide)NiIIbromide

The crystal structure of tetrakis(thioacetamide)nickel(II) bromide has been determined from three dimensional counter data at ambient room temperature. With λ = 0.71068A the cell constants are: a = 15.530±0.004A, b = 14.989±0.004A, c = 9.310± 0.002A, γ = 118.9±0.1°, D c = D m = 1.82 g cm −3 B2/b, Z = 4. Solution of the structure was achieved by standard heavy atom techniques and refinement by full matrix least squares with anisotropic temperature factors resulted in a final R of 0.068. The structure is composed of Ni(SCNH 2 CH 3 ) 4 2+ molecular ions and bromide ions. The Ni atom is on a crystallographic center of symmetry requiring the Ni and its four sulfur neighbors to lie in the same plane. The bromide ions are essentially in axial positions with long NiBr distances of 3.599±0.004A. The two crsytallographically independent NiS distances are 2.216 and 2.222 both ±0.009A, while the SNiS angle is 87.3±0.4°. From the NiSC angles of 112(1)° Av. it is clear that the sulfur atom uses an sp 2 lone pair of electrons to form the metal-sulfur sigma bond. The geometry of the complex is such that the Ni, Br and thioacetamide groups related by a center of symmetry are almost coplanar, i.e. , when the molecule Ni(SCNH 2 CH 3 ) 4 Br 2 is viewed down the NiBr axis. all atoms lie in one of two planes related by a 90° rotation about this axis. This orientation arises from a combination of hydrogen bonding and electronic effects.
Nanoindentation and nanoscratch measurements on silicone thin films synthesized by pulsed laser ablation deposition (PLAD)

Nanoindentation and nanoscratch studies were conducted on silicone thin films synthesized by pulsed laser ablation deposition (PLAD). The nanoindentation studies showed that the modulus of the silicone films varied as a function of the energy density of deposition. The modulus values measured for PLAD silicone films were in the range of 1–6 GPa compared to 5–10 MPa reported for a typical silicone elastomer. Nanoscratch measurements also showed that PLAD silicone films exhibited much greater scratch resistance compared to silicone elastomer. These studies demonstrated that, even for low energy density depositions, the PLAD process can produced films which were are stronger and more abrasion resistant than conventional cross-linked silicone elastomers.
Evaluation of fatigue life and crack growth rates in 7050-T7451 aluminum plate for T-L and L-S oriented failure under truncated spectra loading

Abstract Spectrum crack growth testing of 7050-T7451 plate was performed for T-L and L-S specimen orientations to determine the influence of spectrum truncation on fatigue crack growth rates and overall life. This testing was performed on center-hole (double crack), flat, rectangular tensile specimens machined from material blanks cut from 10.16 cm plate. Additional comparison T-L tests were also accomplished using blanks from available 7050-T7451 1.27 cm plate. Behavior of through-thickness long (>5 mm) cracks is examined. Spectrum loading used for the testing was based on a nominal fighter load spectra and truncation levels of testing were comprised of baseline (5%), plus 20% and 30% ranges. The target, ordered tensile-compressive, stress levels were based on a combination of legacy and predicted use of US fighter aircraft. Results produced representative trends in life-to-failure increases for truncation levels relative to 5% truncated levels for the L-S and T-L orientation specimens. Crack growth rate data was recorded and comparisons are exhibited for varied orientation and crack length. Findings show that although relatively small changes in life are experienced due to orientation, L-S oriented plate material life is affected by the greatest extension of up to 17%. Crack growth rates for shorter cracks in the L-S material exceed growth rates in the T-L oriented material by more than two times the rate. Characteristics of splitting, crack wandering, branching, and shielding were observed in the L-S specimen tests. These potentially undesirable characteristics resulted in temporary crack arrest or retardation in the direction perpendicular to loading and resulted in overall specimen rupture well beyond the life predicted critical crack lengths.
Crystallization and saturation front propagation in silicic magma chambers

Abstract The cooling and crystallization style of silicic magma bodies in the upper crust falls on a continuum between whole-chamber processes of convection, crystal settling, and cumulate formation and interface-driven processes of conduction and crystallization front migration. In the end-member case of vigorous convection and crystal settling, volatile saturation advances downward from the roof and upward from the floor throughout the chamber. In the end-member case of stagnant magma bodies, volatile saturation occurs along an inward propagating front from all sides of the chamber. Ambient thermal gradient primarily controls the propagation rate; warm (⩾40 °C/km) geothermal gradients lead to thick ( 1200 + m ) crystal mush zones and slow crystallization front propagation. Cold (
Ropy pahoehoe: Surface folding of a viscous fluid

Abstract The regularly spaced surface structure observed on ropy pahoehoe basalt flows may be interpreted as folds which develop at the surface of a fluid whose viscosity decreases with depth. Folds form by the selective amplification of an irregular waviness in surface shape during shortening of the flow surface. The development of a regular fold arc length, predicted by folding theory, is reflected in the length scale of pahoehoe ropes. Pahoehoe fold arc lengths and the strength of the folding instability are determined by: (1) the ratio of the surface viscosity to the interior viscosity; (2) the thickness of the thermal boundary layer across which the viscosity changes; and (3) the ratio of the surface compressive stress to a stress related to the weight of the lava. The braided appearance of many ropy pahoehoe flows can be explained by a superposition of two episodes of folding.
On‐line determination of sputtered depth in a radio frequency glow discharge atomic emission source by laser confocal displacement

A new method of sputtered depth determination was evaluated for glow discharge (GD) analysis of solid samples. Although sputter analysis methods like GD may characterize samples in terms of both composition and spatial (depth) distribution of those components, quantitative analysis may suffer significantly from uncertainties in sputter rate (depth) determinations. The study described in this paper was conducted in an effort to achieve true depth profile capabilities for the radio frequency glow discharge atomic emission spectroscopy (r.f.-GD-AES) source, however the results are applicable to any sputter-type analysis method. Detailed here is a unique system by which sputter depth information may be collected simultaneously with operation of the GD plasma, with only minimal influence from sample matrix or plasma conditions. As such, the method enables the determination of real-time sputter depth. This achievement was made possible by the use of a laser confocal displacement sensor (LCDS) that optically measures the distance between a mounted sensor head and the sample surface. Very simply, the LCDS measures the displacement of the sputter-exposed surface relative to the original sample. The results outlined in this report indicate that the laser confocal technique has great potential as an advancement to depth-resolved analysis by r.f.-GD-AES. Statistical figures of merit include an experimental depth resolution of -1 μm and a sample-to-sample reproductibility of ∼5% RSD. Methods of improving further the capabilities of the system described here are also outlined.
Immune Mechanisms in Byssinosis

The pathogenesis of byssinosis has been attributed to several different immunopathologic mechanisms, including a type III (immune complex) pulmonary injury. To further examine this type III theory, sera (Monday preshift) from 59 cotton textile workers were examined by gel diffusion and counterimmunoelectrophoresis for precipitating antibodies to aqueous extracts of cotton bract, carpels, stems, leaves, immature cotton bract, carpels, stems, leaves, immature cotton lint, and cardroom cotton dust. Sera were also collected from 35 nonexposed normal volunteers and examined similarly. No true precipitating antibodies to these extracts could be detected in any of the control or worker serum samples. The aqueous extracts of cardroom cotton dust and cotton stems were found to contain naturally occurring components that precipitated (in agarose gel) beta-lipoprotein and gamma-globulins (mostly IgG) in a nonimmunologic manner. Sera from normal human controls and cotton textile workers all produced identical patterns of reaction with these two extracts. Treatment of these extracts with polyvinylpolypyrrolidone, a specific insoluble adsorbent for polyphenolic tannins, eliminated this pseudoimmune reaction. Although the role this pseudoimmune reaction may play in the pathogenesis of byssinosis is still unknown, it demonstrates the problems associated with laboratory-based investigations of the immunologic aspects of byssinosis.
Saturn's E ring

Abstract The E ring is a loose collection of debris orbiting Saturn well outside the classical ring system. Compared to the classical ring system, the E ring is extraordinarily tenuous but occupies an enormous volume. The optical depth has a pronounced maximum near the orbit of Enceladus, which is therefore widely assumed to be the source of ring material. Optical properties of the ring suggest a collection of micron-sized spheroids whose composition is generally supposed to be water ice in accordance with the assumed Enceladus source. Apart from its unusual physical properties, the very existence of the E ring as a permanent feature of the Saturn system is problematical. The particles of the ring are susceptible to erosion by ion sputtering and outward transport by ion drag. Lifetimes against either of these processes in the presence of observed ion populations are estimated to be no more than a few thousand years, and it is not clear that Enceladus can replenish the ring particles continuously on such a time scale. It has thus been suggested that the E ring is a transient feature of the Saturn system, resulting from an episodic disturbance of Enceladus (e.g., a sizeable meteoroid impact or tectonic event) in the recent past. In any case, the E ring presently provides a convenient natural probe of magnetospheric transport processes because it presents a marginally significant cross section for the absorption of magnetospherically-trapped particles traversing its volume.
Business, ethics and law

The comparative seriousness of business law and business ethics gives some business people the impression that there is nothing important in business ethics. The costly penalties of illegal conduct compared to the uncertain consequences of unethical conduct support a common illusion that business ethics is much less important than law for business people. To dispel the illusion I distinguish two perspectives from which we can view the relation of business and normative systems: the internal and external perspectives. I show that in one perspective, ethics is hardly less important than law, and in the other perspective it is more important, more fundamental than law. I conclude with a discussion of why business persons must place ethical and legal rules ahead of profits.
Local employment, poverty, and property value effects of geographically-targeted tax incentives: An instrumental variables approach

Abstract The federal Empowerment Zone (EZ) program is a set of tax incentives targeted to areas of select cities. I estimate the effect of the EZ program on employment, poverty, and property values by comparing areas that received an EZ to areas that applied (and qualified), but were rejected. Because of endogeneity concerns, I use political representation to instrument for EZ designation. OLS results show a positive and statistically significant effect of the program on employment and poverty. IV estimates suggest the program had no effect on employment and poverty, and instead had a large statistically significant effect on property values.
Zones of representation for PM10 measurements along the US/Mexico border

The 'Imperial/Mexicali Valley Cross-Border PM10 Transport Study' acquired a database of meteorological and air quality measurements to determine source contributions to elevated PM10 concentrations and to estimate transport of PM10 between the US and Mexico. The study was conducted from 13 March 1992 to 29 August 1993, in a 80-km long by 20-km wide area spanning the US/Mexico border approximately 200 km inland from the coast of the Pacific Ocean, with monitoring sites located in the Imperial Valley on the US side and in the Mexicali Valley on the Mexico side. Measurements of PM 10 (particles with aerodynamic diameters less than 10 microm) mass, elements, water-soluble cations (i.e. sodium, potassium, ammonium) and anions (i.e. chloride, nitrate, sulfate), organic and elemental carbon and particle light absorption were acquired at two base sites on an every-sixth-day schedule supplemented by daily monitoring during winter and 4 times per day monitoring during intensive periods. Measurements were also taken at as many as 30 neighborhood (satellite) sites during week-long intensive monitoring periods in spring, summer and winter. This paper examines the zones of representation of long-term PM10 monitors by comparing their measurements with those from a spatially dense network of satellite sites. PM10 concentrations at the Mexicali site were consistently 30 to 50% higher than those observed at the Calexico site, even though the two sites were only 12 km apart. Distinct diurnal variations were found, with 6-h average PM10 concentrations often varying by a factor of 2 throughout the day - lowest during afternoon (12.00-18.00 h PST) and highest during night time (18.00-24.00 h PST). On average, crustal material accounted for 32-35% of annual-average PM10, carbonaceous aerosol for 20-30%, and ionic species for 8-10%. Levels of trace elements and sea salt were in the range of 1-4% of PM10. Significant concentration variations were found within the study area. PM10 concentrations in Mexico were double those in the US, decreasing with increasing northerly distance.
Healing modes correlate with visuotectal pattern formation in regenerating embryonic Xenopus retina

Abstract After removal of the nasal or the temporal two-thirds of the embryonic (stage 32) eye, the remaining one-third sized fragment undergoes wound healing and then, in most cases, regenerates to form a new eye. Using gross anatomy and histology techniques, we categorized eye fragments into three healing mode categories over the first 24 hr after surgery (stage 37–38). Representative animals were reared through metamorphosis and their visuotectal projections were assayed using standard electrophysiology techniques. In the “rounded-up” healing mode, the cut edges of the fragment pinch to close the wound; retinal cell type layers (pigmented retinal epithelium ( pre ), photoreceptors, interneurons, ganglion cells) and a lens are present by 24 hr postsurgery. No extraneous or disorganized cells are present either internal or external to the fragments. These fragments regenerated to form normal projections 83% of the time and pattern duplicated projections only 17% of the time. In the “intermediate” healing mode, wound closure is not complete by 24 hr post surgery and groups of disorganized cells are present in the fragment and amassed between the healing cut edges. These fragments formed pattern duplicated projections 72% of the time. In the tongue healing mode, an ectopic mass of cells, contiguous with the main body of the fragment, forms a supernumerary retina in the region of the ablation. At 24 hr post surgery, the cells of the main body fragment form retinal layers; the cells of the tongue, excluding the presence of differentiated pre cells, remain undifferentiated, resembling ciliary margin. The cut edges of the main body fragment eventually fuse with the tongue to form a single eyeball. Tongue fragments formed pattern duplicated projections 100% of the time. In addition, pattern duplicated points derived from nasal fragments appeared most often in the posterior region of the tectum, the normal site of innervation of the nasal retina. This differed significantly from temporal fragment derived duplicated points which appeared more often in the front of the tectum, the normal site of innervation by temporal retina. Thus, the specificity of pattern duplicated innervation is related to the positional values remaining in the fragment after partial retinal ablation. The data indicate that cell movements during healing, whether overt as in the tongue healing mode, or remaining internal to the fragment as in the intermediate healing mode, are intimately correlated with pattern forming mechanisms which underlie pathological visuotectal duplication.
Hormesis and risk assessment

It is postulated in this paper that at low doses all chemicals have hormetic/hormoligotic (beneficial) effects in living organisms. It has been known since Paracelsus that at high doses all chemicals are toxic. The combination of low and high dose effects can be empirically described by a β-curve or an inverted β-curve. A mathematical method is suggested to determine the maximum of the β-curve or the minimum of the inverted β-curve, yielding a point estimate for risk assessment.
Adventurer in Genome Science

A Life Decoded . My Genome: My Life. By J. Craig Venter . Viking, New York, 2007. 416 pp. $25.95, C$31. ISBN 9780670063581. Allen Lane, London. £25. ISBN 9780713997248. The author recounts the course of his life to date and his quests in genome sequencing and synthetic life.
Coronary artery spasm: involvement of small intramyocardial branches

A study was conducted to determine if the small (resistance) vessels of the coronary circulation could undergo spasm comparable to that of the major conductance (epicardial) arteries which in the rat measure 275-300 micron in diameter. This information may be relevant to the growing evidence of ischemic myocardial disease without significant coronary atherosclerosis or even spasm of the larger vessels. Vascular corrosion casts of the coronary circulation were prepared in the rat 20 min after intravenous injection of arginine vasopressin, a powerful coronary constrictor substance, under continuous electrocardiographic monitoring. Electrocardiographic changes observed consisted of S-T segment elevation and conduction disturbances, implying ischemic effects on the myocardium. Corrosion casts revealed spasm of smaller arteries only (50-150 micron diameter). Controls (vehicle-injected or untreated) showed no abnormalities of the coronary vasculature. These results suggest that myocardial vessels of this size are comparable in their potential for spasm to the large conductance arteries. Similar findings in patients involving smaller vessels could explain ischemic myocardial events in the absence of significant spasm, or organic stenosing pathology of major coronary arteries. As a corollary, it is suggested that the term "coronary artery spasm" could be enlarged in its definition to include other levels of the coronary circulation rather than that of the large conductance arteries alone.
Physiologic goal-directed therapy in the perioperative period: the volume prescription for high-risk patients.

ONVENTIONAL PERIOPERATIVE hemodynamic management based on assumed preoperative volume deficits, blood pressure, heart rate, and urine output is not reliable for guiding volume therapy to avoid inadequate perioperative tissue perfusion. Goal-directed therapy (GDT) has been used to describe a wide variety of interventions and approaches to hemodynamic management tailored to patient-specific physiologic goals. GDT in the perioperative period involves measurement of an individual patient’s oxygen flux or reliable surrogates and interventions objectively directed to augment flow. Successful GDT includes assessment of the adequacy of these interventions in a patient-specific context. The authors present the Physiologic Optimization Program (POP) as a rational physiologic approach to perioperative hemodynamic
Universal quantum computation with ideal Clifford gates and noisy ancillas

We consider a model of quantum computation in which the set of elementary operations is limited to Clifford unitaries, the creation of the state |0>, and qubit measurement in the computational basis. In addition, we allow the creation of a one-qubit ancilla in a mixed state rho, which should be regarded as a parameter of the model. Our goal is to determine for which rho universal quantum computation (UQC) can be efficiently simulated. To answer this question, we construct purification protocols that consume several copies of rho and produce a single output qubit with higher polarization. The protocols allow one to increase the polarization only along certain "magic" directions. If the polarization of rho along a magic direction exceeds a threshold value (about 65%), the purification asymptotically yields a pure state, which we call a magic state. We show that the Clifford group operations combined with magic states preparation are sufficient for UQC. The connection of our results with the Gottesman-Knill theorem is discussed.
Cognitive Approaches to Pain Control: Common Factors Underlying Their Effectiveness

The author reviews the cognitive approaches to pain control and discusses how expectancy of success in general and self-efficacy in particular mediate successful outcomes.
Comparison of Electronic Transport Characterization Methods for Alkanethiol Self-Assembled Monolayers†

Room-temperature charge transport is investigated for various-length alkanethiol self-assembled monolayers using three different characterization methods, in which lateral areas span from the nanometer to the micrometer scale. In each method, the measured current−voltage characteristics are analyzed with metal−insulator−metal tunneling models. Transport parameters are determined where possible and compared across methods, as well as to previously reported values. Advantages and limitations of each method for characterizing molecular junctions are highlighted.
Optical loss measurement of low-loss thin-film waveguides by photographic analysis.

Photographic film was used to measure low intensities of guided light scattered from three different thin-film optical waveguides. The technique is shown to permit measurement of optical loss down to 0.07 dB/cm. The method involves the taking of a photograph of a guided light beam (λ = 632.8 nm) and the use of a microdensitometer to measure the two-dimensional scattered intensity profile. The sensitivity of the photographic film permits the measurement of low light levels, and the beam profile information permits the evaluation of the uniform scattering assumption. The technique can be adapted to channel waveguide loss by using high-definition photographic film. Additionally, the use of infrared-sensitive film can permit the technique to measure loss in the infrared.
CRITICAL COMPARISON BETWEEN TIME- AND FREQUENCY-DOMAIN RELAXATION FUNCTIONS

Considerable work has been performed on providing a theoretical basis for the Kohlrausch-Williams-Watts (KWW) and Havriliak-Negami (HN) relaxation functions. Because of this, several papers have examined the ``interconnection'' of these two functions. In this paper, we demonstrate that, with achievable instrumental sensitivity, these two functions are distinguishable. We further address the issue of the ``universal'' limiting power laws and the ability to obtain the exponents associated with them. Finally, the stability and accuracy of our numerical Laplace transform is demonstrated by comparison between functions with known analytical time and frequency solutions. The stability of our algorithm indicates that the method of Alvarez and co-workers [F. Alvarez, A. Alegr\'{\i}a, and J. Colmenero, Phys. Rev. B 44, 7306 (1991)] is an unnecessary approximation for converting between the time and frequency domain.
Nickel(II) complexes bonded to 12-membered macrocyclic ligands

Abstract Information has been obtained on how ring size, steric factors and the mode of coordination of tetraaza macrocycles will affect the field strength of the macrocycle and how these parameters affect the equilibrium in water or in a water-ethanol mixture between the five-coordinate nickel(II) complexes containing the macrocycle, R 4 [12]aneN 4 , where R is CH 3 and CH 2 C 6 H 5 , and the planar [Ni(R 4 [12]aneN 4 )] 2+ species. On the basis of spectral data it is concluded that steric factors influence the ligand field strength more than the size of the macrocycle for macrocycles that do not bond in a planar manner to the nickel(II). However, for square planar complexes both the size of the macrocyclic ligand and the steric factors play significant roles in the ligand field strength. The equilibrium between the high spin, five-coordinate, [Ni(R 4 [12]aneN 4 )H 2 O] 2+ complexes and the planar or nearly planar [Ni(R 4 [12]aneN 4 )] 2+ is dominated by the solvation properties of these complexes. The more carbon atoms on the R group, the larger the K , ΔS and ΔH values for the above equilibrium. In the presence of excess chloride ions, [Ni(Me 4 [12]aneN 4 )H 2 O] 2+ is converted to [Ni(Me 4 [12]aneN 4 )Cl] + . By increasing the percentage of ethanol in an ethanol-water mixture of [Ni(Me 4 [12]aneN 4 )Cl 2 , the equilibrium shifts to produce more [Ni(Me 4 [12]aneN 4 )Cl] + and less [Ni(Me 4 [12]aneN 4 )H 2 O] 2+ . The tetrabenzyl[12]aneN 4 nickel(II) complex is more difficult to oxidize and easier to reduce than the tetramethyl[12]aneN 4 nickel(II) complexes and the chloride complexes are easier to oxidize than the nitrate complexes in CH 3 CN. In water and in ethanol-water mixtures the [Ni(Me 4 [12]aneN 4 )H 2 O] 2+ /[Ni(Me 4 [12]aneN 4 )H 2 O] + couple is quasi-reversible but in CH 3 CN only the cathodic reaction is observed.
Laboratory and Field Evaluations of Polyacrylamide Hydrogel Baits Against Argentine Ants (Hymenoptera: Formicidae)

The development of effective baits to control the Argentine ant, Linepithema humile (Mayr), has been problematic because foragers prefer sweet liquids, while many toxicants are insoluble in water and liquid baits are generally difficult to deliver. The incorporation of thiamethoxam and sucrose solutions into a water-absorbing polyacrylamide hydrogel provides a unique and novel carrier and method of application for liquid baits. Formulations of thiamethoxam affected the size of the hydrogels, and sucrose solutions containing 0.0003% technical thiamethoxam provided hydrogels as large as those made with 25% sucrose solution or deionized water. Concentrations of thiamethoxam as low as 0.000075% in the hydrogels provided 50% kill of workers within 3 d in a laboratory setting. In small colony studies, baiting with 0.00015 and 0.000075% thiamethoxam hydrogels provided 100% mortality of workers and queens within 8 d. An enzyme-linked immunosorbent assay indicated that thiamethoxam was absorbed into the interior of the polyacrylamide matrix. The water loss rates of the hydrogels were dependent upon the relative humidity. Polyacrylamide hydrogels with >50% water loss were less attractive to ants. Field studies in highly infested areas indicated that concentrations of 0.0006 or 0.0018% thiamethoxam were more effective than 0.00015%. Hydrogels may provide a cost-effective alternative to providing aqueous baits to control Argentine ants.
Automatic keyword extraction for the meeting corpus using supervised approach and bigram expansion

In this paper, we tackle the problem of automatic keyword extraction in the meeting domain, a genre significantly different from written text. For the supervised framework, we proposed a rich set of features beyond the typical TFIDF measures, such as sentence salience weight, lexical features, summary sentences, and speaker information. We also evaluate different candidate sampling approaches for better model training and testing. In addition, we introduced a bigram expansion module which aims at extracting ldquoentity bigramsrdquo using Web resources. Using the ICSI meeting corpus, we demonstrate the effectiveness of the features and show that the supervised method and the bigram expansion module outperform the unsupervised TFIDF selection with POS (part-of-speech) filtering. Finally, we show the approaches introduced in this paper perform well on the speech recognition output.
Standard and high dose chemotherapy for advanced soft tissue sarcomas

While significant improvements have been made in the management of localized soft tissue sarcomas, enabling the realization of better functional results and a better overall outcome, progress in metastatic disease has been less than impressive. Adriamycin and DTIC based chemotherapy programs have resulted in response rates of upto 50%, with a small but finite cure fraction, especially in conjunction with surgical resection of residual abnormalities. The decade of the 80s experienced a considerable amount of enthusiasm in exploring the role of ifosfamide and mesna, and identified its definite usefulness as an effective salvage regimen with response rates of approximately 25%-30% in adriamycin failures. Studies evaluating the role of ifosfamide as up-front line agent in combination with adriamycin have met with increased toxicities without a significant additive therapeutic benefit, probably as a result of compromised dose intensity of each individual agent. The steep linear log-dose response relationship of alkylating agents and adriamycin constitutes the theoretical rationale for use of higher doses of chemotherapy, which have become feasible, with the advent of growth factors for bone marrow support. While this approach seems promising in its infancy, with improved complete and overall response, its ultimate effect on survival is anxiously awaited. The limited experience available in the literature with even more aggressive approaches like marrow ablative doses of chemotherapy followed by bone marrow transplantation, have been uniformly disappointing, with extremely short lived responses and extremely high morbidity and cost. As clinical research continues to improve our understanding and ability to implement the currently available therapeutic armamentarium, the search for newer and better drugs needs to continue.(ABSTRACT TRUNCATED AT 250 WORDS)