cssi/SciSciGPT-SciSciNet huggingface dataset:
A comparison of the nodulation of diploid and tetraploid varieties of red clover inoculated with different Rhizobial strains

The effectiveness of three different strains ofRhizobium trifolii on a diploid and a tetraploid variety of red clover (Trifolium pratense) grown in aseptic mineral-agar culture was compared. It was found that with two of the rhizobial strains tested, the tetraploid plants were slower to nodulate than the diploid plants, but that a hundred per cent nodulation was obtained in both cases. With the third strain, however, a sixty-six per cent nodulation of the diploid plants was reduced to an eight per cent nodulation of the tetraploids.
Solid-state NMR investigations of peptide-lipid interactions of the transmembrane domain of a plant-derived protein, Hcf106.

Abstract The chloroplast twin arginine translocation system transports highly folded precursor proteins across the thylakoid using the protonmotive force as its only energy source. Hcf106 and another thylakoid protein, cpTatC compose the precursor receptor complex. Hcf106 is predicted to contain a single amino terminal transmembrane domain (TMD) followed by a Pro–Gly hinge, an amphipathic α-helix, and a loosely structured carboxyl terminus. Hcf106 has been shown biochemically to insert spontaneously into thylakoid membranes; however, how this occurs is not understood. To investigate how Hcf106 inserts itself into the membrane unassisted, solid-state NMR spectroscopy was used to investigate the membrane activity of the TMD. A synthetic peptide of the Hcf106 TMD was incorporated into multilamellar vesicles made of 100% 1-palmitoyl-2-oleoyl-sn-glycero-phosphocholine (POPC) or 85%:15% ratio with monogalactosyl diacylglycerol (POPC/MGDG) to probe peptide–lipid interaction. Solid-state 31P NMR and 2H NMR spectroscopic techniques were used to reveal peptide perturbations of the phospholipid membranes. Changes in spectral lineshape, chemical shift anisotropy width, 31P T1 relaxation time and SCD order parameters demonstrated that the Hcf106 TMD peptide interacted with the phospholipids. Furthermore, the comparison between POPC and POPC/MGDG multilamellar vesicles indicated that lipid bilayer composition affected the peptide–lipid interaction with the peptide interacting preferentially with vesicles that more closely mimic the thylakoid.
New simple model of dynamic hysteresis

Although the most commonly used hysteresis models are static, in some applications these models constitute an unacceptable simplification of physical behaviour. This includes ferro-magnetic hysteresis, plasticity and friction, which are dynamic phenomena. Consequently, this paper is aimed at presenting a new simple model of dynamic hysteresis, which is more appropriate for modelling of real-life hysteresis effects. The suggested model might be used as a building block for the development of various dynamic hysteresis models. It is proved that at low input rates, this model is closely related to static hysteresis, and it therefore constitutes a generic framework for modelling of hysteresis. Finally, it is shown that stability analysis of a closed-loop system containing simple dynamic hysteresis in feedback can be analysed in a straightforward manner using absolute stability theory.
EVALUATION OF PEPPER (CAPSICUM ANNUUM) FOR MANAGEMENT OF DIABETES AND HYPERTENSION

Natural α-amylase and α-glucosidase inhibitors from food-grade plants offer an attractive strategy to control postprandial hyperglycemia for type 2 diabetes management. Concurrently associated macrovascular complication of hypertension can be managed by similar extracts by inhibition of angiotensin I-converting enzyme (ACE ). In this study, nine types of pepper were investigated for inhibitory activity against said enzymes. Several pepper extracts had high α-glucosidase inhibitory activity, which was not correlated to total phenolic content and free radical scavenging-linked antioxidant activity. Select extracts such as Green pepper and Long hot pepper had less or no inhibitory effect on the α-amylase activity, which indicates the potential for reduced side effects. Among various water extracts, Yellow, Cubanelle and Red pepper had the highest ACE inhibitory activity. Therefore, combinations of pepper could be screened for dietary management of type 2 diabetes, associated hypertension and microvascular complications linked to oxidative dysfunction, and provide the basis for clinical studies.
An Algebraic Algorithm for Nonuniformity Correction in Focal-Plane Arrays

A scene-based algorithm is developed to compensate for bias nonuniformity in focal-plane arrays. Nonuniformity can be extremely problematic, especially for mid- to far-infrared imaging systems. The technique is based on use of estimates of interframe subpixel shifts in an image sequence, in conjunction with a linear-interpolation model for the motion, to extract information on the bias nonuniformity algebraically. The performance of the proposed algorithm is analyzed by using real infrared and simulated data. One advantage of this technique is its simplicity; it requires relatively few frames to generate an effective correction matrix, thereby permitting the execution of frequent on-the-fly nonuniformity correction as drift occurs. Additionally, the performance is shown to exhibit considerable robustness with respect to lack of the common types of temporal and spatial irradiance diversity that are typically required by statistical scene-based nonuniformity correction techniques.
Garlic attenuates hypercholesterolemic risk factors in olive oil fed rats and high cholesterol fed rats

Abstract This study was undertaken to compare the effects of garlic (G) on hypercholesterolemic risk factors in rats fed with corn oil (C) or olive oil (O) with and without cholesterol (Ch) enrichment in the diet. Male Sprague–Dawley rats ( n =6 per group) were fed semi-purified diets containing 5% oil with or without cholesterol (Ch) or garlic (G) for 21 days. In the C fed rats, addition of dietary Ch, there was a redistribution of Ch from HDL to LDL class. In contrast, 1% Ch added to O diets produced a 4-fold increase in serum Ch compared with levels in rats fed O without Ch. This was associated with a 14-fold increase in LDL Ch and a 7-fold decrease in HDL Ch levels. Addition of 2% G had no effect on the distribution of serum Ch between HDL and LDL Ch in C+Ch fed rats, but in O+Ch fed rats, G halved the increase in serum Ch and LDL and attenuated the decrease in serum HDL by 23%. The results suggest that the dietary O regulated the levels of serum in Ch loaded rats. G attenuated serum Ch in O fed rats and decreased serum risk factors, both total Ch and LDL-C ratio and LDL–Ch/HDL–Ch ratio.
Low-Field-Orientation Effect on REBCO Tape Performance and Its Power Cable Application

Low field characteristics, including field orientation dependence relations for four different commercially available REBCO tapes, were investigated in an external field of up to 0.3 T at 77 K. A design method of the performance of a twisted stacked-tape conductor (TSTC) has been developed for a power transmission line. Cable critical current is obtained from an averaged self-field distributed over the cable cross section and the minimum critical current obtained from the field orientation dependence in transverse fields experimentally measured for the single tapes. The performance of three types of TSTCs, i.e., single-, double-, and triple-channel configurations, has been assessed for the four REBCO tapes.
Incidence and predictors of appropriate therapies delivered by the implantable cardioverter defibrillator in patients with ischemic cardiomyopathy: A systematic review

Abstract Background Although the implantable cardioverter defibrillator (ICD) improves the survival of patients at increased risk of sudden cardiac death due to systolic heart failure, ICD shocks have been associated with both worse survival and quality of life. We performed a systematic review of primary prevention ICD studies to evaluate the incidence and clinical predictors of appropriate ICD shocks or anti-tachycardia pacing (ATP) in patients with ischemic cardiomyopathy. Methods We performed a literature search in MEDLINE. Eligible studies had to be full text, written in the English language, performed in adults aged ≥19, and published from 1999 through April 2014. Results Of 289 identified studies, 9 met all our inclusion criteria. The mean length of follow up ranged from 17 to 45.5months. The incidence of appropriate ICD therapy varied from 17% to 31%. Among those studies, only 4 included data on the clinical characteristics of appropriate ICD therapy recipients. Characteristics associated with appropriate ICD therapy included male sex, advanced New York Heart Association class, non-sustained ventricular tachycardia, and lower serum creatinine. Patients who received appropriate therapy were also less likely to be on a beta-blocker. Left ventricular ejection fraction was not significantly different between patients who received appropriate ICD therapy and those who did not. Conclusion The incidence of appropriate ICD therapy is not trivial in patients with ischemic cardiomyopathy and a primary prevention ICD. Predictors of appropriate ICD therapy have not been adequately assessed in large patient populations. As such, large prospective studies of predictors of appropriate ICD therapies are needed.
Vertical coupler with separated inputs and outputs fabricated using double-sided process

A novel vertical coupler used as a wavelength multiplexer with separated input and output waveguides is demonstrated. The wafer fusion technique enables both frontside and backside processing of the thin epitaxial films. A vertical coupler with a 4 mm interaction region demonstrates 20 nm wavelength spacing.
Self-management of nutritional risk among older adults: A conceptual model and case studies from rural communities

Abstract Older adults experience both social and physical changes that require them to make adaptations in the way they meet their nutritional needs. Failure to make such adaptations can compromise health and quality of life. However, research linking nutrition to behaviors and resources of elders is hampered by lack of an appropriate conceptual model. Case-based analysis of transcripts of in-depth ethnographic interviews with rural elders in the southeastern US is used to develop a model of nutritional self-management, defined as the behavioral regimen that older persons use to obtain food, prepare food and maintain food security. Behaviors used to accomplish these nutritional self-management tasks can be drawn from four domains (self-care, informal support, formal support and medical care) and the strategy 's adequacy can be evaluated by measures of nutritional status. Research applications of the model, as well as its link to the concept of adaptation are discussed.
Simulation of future stream alkalinity under changing deposition and climate scenarios.

Abstract Models of soil and stream water acidification have typically been applied under scenarios of changing acidic deposition, however, climate change is usually ignored. Soil air CO 2 concentrations have potential to increase as climate warms and becomes wetter, thus affecting soil and stream water chemistry by initially increasing stream alkalinity at the expense of reducing base saturation levels on soil exchange sites. We simulate this change by applying a series of physically based coupled models capable of predicting soil air CO 2 and stream water chemistry. We predict daily stream water alkalinity for a small catchment in the Virginia Blue Ridge for 60 years into the future given stochastically generated daily climate values. This is done for nine different combinations of climate and deposition. The scenarios for both climate and deposition include a static scenario, a scenario of gradual change, and a scenario of abrupt change. We find that stream water alkalinity continues to decline for all scenarios (average decrease of 14.4 μeq L − 1 ) except where climate is gradually warming and becoming more moist (average increase of 13 μeq L − 1 ). In all other scenarios, base cation removal from catchment soils is responsible for limited alkalinity increase resulting from climate change. This has implications given the extent that acidification models are used to establish policy and legislation concerning deposition and emissions.
Topographic influences on soil water and spring wheat yields on reclaimed mineland

Topographic positions on undistributed soils affect available soil water and crop yields. Reclaimed minelands are required by regulation to have productivity levels equal to or greater than premine levels. Since a normal reclamation technique is to place uniform depths of topsoil and subsoil across the topography, this technique often changes the topsoil and subsoil depths from the premine condition. The objective of this research was to determine if these changes in topsoil and subsoil depths have resulted in effects on soil water and crop yields unlike those documented for undisturbed soils. This study was initiated on reclaimed mineland in 1986 at two North Dakota coal mines where topographic positions (summit, shoulder, backslope, and footslope) were monitored for 6 yr for available water at planting, spring wheat (Triticum aestivum L.) yields, and soil water recharge from harvesting to planting the following year. Results showed that downslope topographic positions had nearly 300% more available soil water at planting (0- to 1.2-m depth due to greater recharge) and generally significantly greater (P=0.10) spring wheat yields than upslope positions. Relationship between total water use and wheat yields were similar to those found for undistributed soils. These results seem to suggest that the uniform depths of replaced topsoil and subsoil have not affected soil water and wheat yields differently on reclamed minelands than on undisturbed landscapers in a semi-arid climate
An integrated approach to the determination of the quantity, distribution, and dispersal of mercury in Lahontan Reservoir, Nevada, USA

Abstract This paper describes an integrated approach to the assessment of Hg contamination in Lahontan Reservoir, Nevada. The study shows that combining geomorphic and geochemical information allows a minimal amount of geochemical sampling to achieve a maximum understanding of contaminant quantity, distribution, and movement within the reservoir. Geochemical data revealed that the chemical variability within the individual stratigraphic units of the reservoir is much less than the between-unit variability. This allowed the spatial distribution of Hg, Au, and Ag to be precisely determined by geologic mapping of the individual stratigraphic units. A total of nine stratigraphic units were defined from four sedimentary environments: eolian, coastal, deep-water, and deltaic. The deep-water and deltaic sediments, which comprise approximately 55% of the reservoir's area, contain the bulk of the Hg, Au, and Ag. The geologic and geochemical data also show that spatial variations in metal concentration are influenced by a complex set of parameters including vertical sediment mixing by shrink-swell processes, dilution by non-contaminated materials, the rate of metal influx to the reservoir, and the sorption potential of the sediments. Mass balance calculations based on cartographic, bulk density, and metal concentration data, show that approximately 3.28 × 10 5 kg of Hg. 2.253 kg (59,600 oz) of Au, and 117,933 kg (3,120,000 oz) of Ag reside within the post-1915 lacustrine sediments. At current market prices these metals are valued at approximately $ 35 million. Recovery of Au and Ag during site remediation would help defray the cost of clean-up operations.
Judging 2D versus 3D square-wave virtual gratings

Haptic virtual texture can enhance people's experience in interacting with virtual objects by providing surface information. We present a study to analyze how people distinguish between 2D and 3D square-wave gratings using a point-source haptic interface. Our analyses were based on objective vibration and force measurements and psychophysical experiments with human subjects. The results indicated that people were unable to detect the difference between the two textures when they moved their hands across textures with either the amplitude or period smaller than 1.52 mm (0.06 inch) for a texture stiffness of 2 N/mm. This result implies that a simple 2-degree-of-freedom haptic interface may be sufficient to convey the same 3-dimensional tactile feeling for certain textures if the textures are small enough.
Histoplasmosis in Patients at Risk for the Acquired Immunodeficiency Syndrome in a Nonendemic Setting

We reviewed 18 cases of histoplasmosis in patients at risk for the acquired immunodeficiency syndrome seen at two New York City hospitals in the past 3½ years. Seventeen patients were Hispanic, including 13 born in Puerto Rico and three in South America. Clinical presentation was subacute, with high fever, weight loss, and mild respiratory symptoms with well-maintained gas exchange. Five patients had normal chest roentgenograms. The most common chest roentgenographic abnormality was diffuse small nodules. A rapid diagnosis was established histologically in 72 percent of patients, most commonly by transbronchial lung biopsy; cultures were positive in 94 percent of patients while serology was positive in five of six patients. Mycobacterium tuberculosis was a concurrent, often unrecognized, pathogen in six cases. Most patients responded to amphotericin therapy. Histoplasmosis may represent an early sign of altered host immunity in the acquired immunodeficiency syndrome.
Non-invasive image analysis evaluation of growth during plant micropropagation

Microcomputerized video image analysis was adapted for rapid, objective, and non-intrusive quantification of shoot growth and development for plants growing in vitro. Custom-developed staging arrangements were essential to insure accurate viewing and representation of the plants in each of three standard culture vessels. Shoot length measurements from digitized culture images were strongly correlated with length measured manually ex vitro. Image analysis weighted density measurements of proliferating microcultures (even with irregular growth habits) provided a reliable indicator of shoot culture fresh weight. Non-destructive time course evaluations of growth rate and quality were demonstrated.
Annular Mhd Physics for Turbojet Energy Bypass

The use of annular Hall type MHD generator/accelerator ducts for turbojet energy bypass is evaluated assuming weakly ionized flows obtained from pulsed nanosecond discharges. The equations for a 1-D, axisymmetric MHD generator/accelerator are derived and numerically integrated to determine the generator/accelerator performance characteristics. The concept offers a shockless means of interacting with high speed inlet flows and potentially offers variable inlet geometry performance without the complexity of moving parts simply by varying the generator loading parameter. The cycle analysis conducted iteratively with a spike inlet and turbojet flying at M = 7 at 30 km altitude is estimated to have a positive thrust per unit mass flow of 185 N-s/kg. The turbojet allowable combustor temperature is set at an aggressive 2200 deg K. The annular MHD Hall generator/accelerator is L = 3 m in length with a B(sub r) = 5 Tesla magnetic field and a conductivity of sigma = 5 mho/m for the generator and sigma= 1.0 mho/m for the accelerator. The calculated isentropic efficiency for the generator is eta(sub sg) = 84 percent at an enthalpy extraction ratio, eta(sub Ng) = 0.63. The calculated isentropic efficiency for the accelerator is eta(sub sa) = 81 percent at an enthalpy addition ratio, eta(sub Na) = 0.62. An assessment of the ionization fraction necessary to achieve a conductivity of sigma = 1.0 mho/m is n(sub e)/n = 1.90 X 10(exp -6), and for sigma = 5.0 mho/m is n(sub e)/n = 9.52 X 10(exp -6).
Methods in biomedical ontology

Research on ontologies is becoming widespread in the biomedical informatics community. At the same time, it has become apparent that the challenges of properly constructing and maintaining ontologies have proven more difficult than many workers in the field initially expected. Discovering general, feasible methods has thus become a central activity for many of those hoping to reap the benefits of ontologies. This paper reviews current methods in the construction, maintenance, alignment, and evaluation of ontologies.
A model for use in the rationing of inventory during lead time

While the traditional solution to the problem of meeting stochastically variable demands for inventory during procurement lead time is through the use of some level of safety stock, several authors have suggested that a decision be made to employ some form of rationing so as to protect certain classes of demands against stockout by restricting issues to other classes. Nahmias and Demmy [10] derived an approximate continuous review model of systems with two demand classes which would permit an inventory manager to calculate the expected fill rates per order cycle for high-priority, low-priority, and total system demands for a variety of parameters. The manager would then choose the rationing policy that most closely approximated his fill-rate objectives. This article describes a periodic review model that permits the manager to establish a discrete time rationing policy during lead time by prescribing a desired service level for high-priority demands. The reserve levels necessary to meet this level of service can then be calculated based upon the assumed probability distributions of high- and low-priority demands over lead time. The derived reserve levels vary with the amount of lead time remaining. Simulation tests of the model indicate they are more effective than the single reserve level policy studied by Nahmias and Demmy.
2,3-Branching benzyl ether dendrimers for the enhancement of dental composites

Abstract The globular and highly branching nature of the 2,3-dihydroxybenzyl motif was utilized in the development of novel dental composite additives. Dental composites were formulated with varying percentages of multi-methacrylated dendritic additives and evaluated for the corresponding influence on material properties. The flexural strength of composites containing only 0.5% of multi-methacrylate dendritic additive improved 21–35%, compared with control. Addition of higher molecular weight (Mw) dendrimers resulted in composites with greater flexural strength. Higher concentrations of additive afforded no additional benefit to the composite strength. The degree of polymerization as a function of increasing additive Mw or concentration indicates a strong dependency on the diffusion coefficient of the dendrimer. Low concentrations of dendritic additive effected up to an 85% decrease in acetone-extractable material from the cured composite matrix. These studies demonstrate the ability of highly globular, highly cross-linking additives to improve composite properties even at very low concentrations.
A socialist-feminist perspective on widowhood

Abstract Becoming widowed is a life transition that many older adults experience. Thus, gerontologists have been interested in studying the effects of bereavement on widowed persons' well-being, their methods of coping with such loss, and factors that contribute to or interfere with adjustment to widowhood. The purpose of this article is to apply a socialist-feminist perspective to these concerns. The article focuses on two topics: economic consequences of widowhood, which are analyzed with reference to the research literature, and issues related to selfsufficiency, which are illustrated with data from a local study.
The Importance of Biological Realism in Dioxin Risk Assessment Models Michael

Mechanistic mathematical models of hepatocarcinogenesis in the female rat were constructed to investigate possible relationships among the Ah, estrogen, and EGF receptors in TCDD hepato-carcinogenicity. Each model generates dose-response curves for the expression of biomarker liver proteins CYP1A1, CYP1A2, and residual plasma membrane EGF receptor consequent to exposure to TCDD. The shapes of the response curves were strongly dependent on the assumed mechanisms of constitutive expression of these proteins. Assuming a constant level of the hepatic Ah receptor, a sigmoidal dose-response of hepatic CYP1A1 to total liver TCDD was computed. However, inclusion of induction of the Ah receptor by TCDD in a physiologically realistic dosimetric model produced a linear low-dose response of CYP1A1. This behavior was computed to arise from the net effect of sublinear response of CYP1A1 mRNA to the concentration of the Ah-TCDD complex and supralinear response of the protein concentration to the mRNA level, illustrating the importance of biological realism in dose-response modeling. The dosimetric model also computed effects of TCDD on the hepatic estradiol concentration and consequent effects on the binding capacity of the EGF receptor and suggests plausible mechanisms for tumor promotion by TCDD. Setting circulating estradiol levels in the model to values typical of the male rat indicated possible sources of the differences in the responses of the EGF receptor and in development of tumors in the two sexes.
Brain TRH and Cyclo (His-Pro) and brain protein in the newborn rat are altered by maternal liquid protein feeding.

Liquid protein diet (LPD) has been shown previously to produce maternal and fetal weight loss and fetal congenital anomalies, including cataracts and craniofacial malformations. Therefore, to examine the effects of LPD in pregnancy upon the central nervous system of pups, pregnant dams were fed either a 20% casein diet ad libitum, a 20% LPD, or pair-fed with a 20% casein diet. LPD was associated with significant maternal weight loss, and pups had significantly lower birth weights (5.14 ± 0.64) than pups from the pair-fed controls (5.70 ± 0.46, p < 0.05). Total brain protein content was reduced significantly in pups of both sexes from pregnant fed LPD. Moreover, the concentrations of two brain peptides neurotransmitters, thyrotropin-releasing hormone (TRH), and its biologically active metabolite, histidyl-proline diketopiperazine Cyclo (His-Pro), were elevated in the pups from LPD-fed mothers. In contrast, there was no significant difference in brain protein or brain peptides in pups from pair-fed mothers vs. pups from mothers fed ad libitum. These data suggest that qualitative alterations of the protein component in maternal dietary composition have deleterious effects upon the ontogeny of the rat fetal CNS, as reflected by reduced total protein and elevated concentrations of TRH and Cyclo (His-Pro).
Manganese oxide thin films prepared by nonaqueous sol-gel processing: preferential formation of birnessite

Abstract High quality manganese oxide thin films with smooth surfaces and even thicknesses have been prepared with a nonaqueous sol–gel process involving reduction of tetraethylammonium permanganate in methanol. Spin-coated films have been cast onto soft glass, quartz, and Ni foil substrates, with two coats being applied for optimum crystallization. The addition of alkali metal cations as dopants results in exclusive formation of the layered birnessite phase. By contrast, analogous reactions in bulk sol–gel reactions yield birnessite, tunneled, and spinel phases depending on the dopant cation. XRD patterns confirm the formation of well-crystallized birnessite. SEM images of Li-, Na-, and K–birnessite reveal extremely smooth films having uniform thickness of less than 0.5 μm. Thin films of Rb– and Cs–birnessite have more fractured and uneven surfaces as a result of some precipitation during the sol–gel transformation. All films consist of densely packed particles of about 0.1 μm. When tetrabutylammonium permanganate is used instead of tetraethylammonium permanganate, the sol–gel reaction yields amorphous manganese oxide as the result of diluted Mn sites in the xerogel film. Bilayer films have been prepared by casting an overcoat of K–birnessite onto an Na–birnessite film. However, Auger depth profiling indicates considerable mixing between the adjacent layers.
Likelihood of spontaneous conversion of atrial fibrillation to sinus rhythm

Abstract Objectives. We sought to determine the likelihood and predictors of spontaneous conversion to sinus rhythm of recent-onset atrial fibrillation (symptoms Background. Although spontaneous conversion of recent-onset atrial fibrillation is common, the likelihood and clinical and echocardiographic predictors have not been fully defined. Such data would be important for management of patients in whom early cardioversion is desired: Cardioversion could be delayed in patients with a high likelihood of spontaneous conversion, and it could be expeditiously pursued if spontaneous conversion is unlikely. Methods. We screened 1,822 consecutive adults admitted to the hospital with atrial fibrillation and prospectively identified 356 patients (45% male, mean age ± SD 68 ± 16 years) with atrial fibrillation of Results. Spontaneous conversion to sinus rhythm occurred in 68% of the study group (n = 242; 95% confidence interval [CI] 63% to 73%). Among patients with spontaneous conversion, the total duration of atrial fibrillation was 48 h in 41 (17%) (p Conclusions. Spontaneous conversion to sinus rhythm occurs in almost 70% of patients presenting with atrial fibrillation of
An inverse transformation for quadrilateral isoparametric elements: Analysis and application

The coordinate transformation for quadrilateral isoparametric elements is well-defined in the finite element literature. However, a corresponding inverse transformation is not found. In fact, it has been commonly believed that no explicit solutions to the inverse transformation problem exist. This paper shows that if geometric considerations are used, a complete set of general solutions to the inverse transformation problem can be derived. An application of the inverse transformation for slope stability analysis is also presented.
Time-dependent behaviour of a stable auroral red arc excited by an electric field

Abstract We examine the electric field hypothesis as a possible explanation of a stable auroral red arc. An electric field perpendicular to the geomagnetic field in the ionosphere heats the ambient F-region electrons and ions. Given large enough electric fields, the electrons can be heated sufficiently to excite the OI (1D) term of atomic oxygen by electron impact, giving rise to the λ6300 emission characteristic of the red arc. The electron and ion heating rates are determined by the relative drift between the plasma and neutral gas. The electric field, acting through ion drag, accelerates the neutral gas in a time scale small compared to the observed lifetime of the arc. If the electron density within the red arc is high, the relative drift between the plasma and neutral gas is significantly reduced and the red arc excitation is effectively shut off because of the consequent lower electron and ion heating rates. For low electron densities, the electric field strength necessary to excite the red arc is far greater than any fields which have been observed. For all electron densities between these two extremes, the calculated features of a red arc excited by a perpendicular electric field cannot be made consistent with both satellite observations of electron temperature and ground-based observations of λ6300 emission. We conclude that it is not possible for a perpendicular electric field to excite a red arc such as observed, and thus support the contention that conduction of heat in the electron gas from the magnetosphere alone is sufficient to excite and maintain the stable auroral red arc.
Boundary behavior of p-harmonic functions in the Heisenberg group

In this paper we study the boundary behavior of nonnegative p-harmonic functions in a bounded domain in the Heisenberg group \({\mathbb H^n}\). Under suitable geometric assumptions on the ground domain \({\Omega\subset \mathbb H^n}\) our main contributions can be summarized as follows: (1) In Theorem 1.1 we obtain an estimate from above stating that any such function should vanish at most linearly like the sub-Riemannian distance from the boundary: $$\frac{u(g)}{u(A_r(g_0))}\leq C^{-1}\frac{d(g,\partial \Omega)}{r},$$ where \({A_r(g_0)\in \Omega}\) is a non-tangential point relative to \({g_0\in \partial \Omega}\). (2) In Theorem 1.2 we establish an estimate from below which states that, away from the characteristic set of Ω, the order of vanishing is exactly linear, i.e.: $$\frac{u(g)}{u(A_r(g_0))}\ge C \frac{d(g,\partial \Omega)}{r}.$$
Variable social vector clocks for exploring user interactions in social communication networks

Social network communication analysis has drawn widespread attention in recent years. Vector clocks can be applied to capture the most recent communication with all other local peers in a social network. A modification of conventional social vector clocks has been previously proposed to deal with the issue of poor scalability without keeping whole temporal views. In this paper, our proposed framework maintains the low bound of how out-of-date each peer can be with respect to others, and also considers the shortest friendship separation to restrict how far information may be transmitted along time-respecting paths. To quantitatively analyse the influence of user interactions over different limitations of friendship distance, we also provide an adaptive incremental updating approach that can exactly recover the real situation in a specified upper bound of friendship distance. Experimental results also show that social vector clocks can be efficiently exploited to improve memory space requirements.
Attenuation correction of SPECT using X-ray CT on an emission-transmission CT system: Myocardial perfusion assessment

The authors present experimental results for attenuation correction of emission tomography through use of an attenuation map derived from X-ray CT data. The X-ray and gamma-ray data were obtained from a third-generation X-ray CT scanner and a single-headed SPECT Scanner juxtaposed to enable systematic registration of SPECT and X-ray CT Images. CT measurements were obtained from known materials at a given X-ray technique, then related to attenuation coefficients at 140 keV. The resulting calibration data were used to generate attenuation maps for the coregistered SPECT data. In addition, phantom studies provided recovery coefficients as a function of object size to compensate for partial volume effects in the coregistered radionuclide data. This technique has been applied to a torso phantom, yielding attenuation maps with an average accuracy error <1%. Reconstruction of the SPECT image without attenuation correction underestimated the regional myocardial activity errors with an average accuracy error of -90%. Reconstruction with attenuation correction reduced the average accuracy error to -37%, but addition of a partial volume correction overestimated the regional myocardial activity concentration by an average error of 94%. The technique has also been applied to small pigs in myocardial perfusion studies by correlating the image-derived myocardial activity concentrations with those obtained directly from excised tissue samples. Correcting for attenuation increased the slope of the regression line from 0.16 to 0.36 (compared with an ideal slope of 1.00.) Adding an additional correction for partial volume effects improved the slope of the regression line to 0.93. The absolute precision error (standard error of the estimate) obtained without correction (2.14 /spl mu/Ci/ml) was degraded by attenuation correction (4.23 /spl mu/Ci/ml) and was also degraded by adding a correction for partial volume errors (10 89 /spl mu/Ci/ml), although the relative precision error without correction (31.2%) was improved by attenuation correction to 27.6% when the images were reconstructed with attenuation correction alone or with a combination of attenuation correction and compensation for partial volume effects.
Electrocatalysis of reformate tolerance in proton exchange membranes fuel cells: Part I

Electrocatalysis of anode electrode tolerance resulting from the presence of both CO and CO2 in the reformer feed was investigated for Pt, Pt � /Ru (1:1) and various atomic ratios of supported Pt:Mo electrocatalysts in proton exchange membrane fuel cells (PEMFCs). In order to elucidate the effects of CO and CO2 in the reformer feed, separate systematic studies were conducted with varying levels of CO and CO2 in H2. The results were used to explain those obtained with a fixed reformate composition: 45% H2, 10 ppm CO, 15% CO2 ,1 % CH 4 balanced with N2. Results with CO in H2 showed that PtMo/C exhibits at least a threefold better CO tolerance as compared to PtRu/C and fourfold with respect to Pt/C. The variation of PtMo atomic composition has a negligible effect on CO tolerance. Additional surface poisoning was detected for all the electrocatalysts studied in the molar ratio (H2:CO2, 40:60 to 60:40). The presence of a reduced CO2 species was confirmed using cyclic voltammetry. An ensemble effect was proposed to explain the variation of tolerance to CO2 as a function of Pt: Mo atomic ratio, this is in contrast to the effect in the presence of adsorbed CO. Interestingly, the overpotential losses in the presence of H2:CO2 for PtMo/C (1:1) and PtRu/C (1:1) were very close. As the Pt content of the PtMo/C alloys was increased, the overpotential losses followed those observed for pure Pt, clearly demonstrating a relationship between overpotential loss and Pt site availability. Despite similar overpotential losses between Pt/C and PtMo/C (5:1), both of which were greater than PtRu/C (1;1) the overpotential loss observed for PtMo in a CO2� /CO reformate mix was far better than for both PtRu/C and Pt/C. # 2003 Elsevier B.V. All rights reserved.
Effect of UV exposure on the surface charge behavior for GaN

The surface charge behavior on n-type GaN was investigated as a function of UV exposure in ambient. It was first noticed that the surface photovoltage (SPV), or change in surface contact potential under UV illumination, could slowly decrease during illumination. The SPV for as-grown samples is ~0.6 eV and can drop by up to 0.3 eV over 1 h of UV exposure in air ambient. We believe that this slow decrease is due to the photo-induced chemisorption of oxygen species. Interestingly, samples exhibit a smaller drop in SPV during continuous UV illumination after many hours of accumulated UV exposure. This can be explained by the UV-induced growth of a thicker surface oxide layer which inhibits electron transfer from the bulk to the surface. The original SPV behavior can be restored by chemical etching to remove the additional surface oxide. We have also investigated the surface behavior by locally charging the surface before and after UV-induced oxide growth. Measurements of the surface contact potential using scanning Kelvin probe microscopy (SKPM) demonstrate that negatively charged regions initially spread laterally on the UV-exposed surface, but not on the clean surface. The UV-induced oxide therefore appears to be relatively conductive and enhance the lateral motion of injected electrons. The discharge of both the negatively and positively charged regions under dark conditions is similar for both the initial and UV-exposed surfaces and shows a logarithmic time dependence.
’SBART 2.4’: An IEC tool for creating two-dimensional images, movies and collages

In this article, the author gives an overview of SBART 2.4, an interactive system used to create abstract two-dimensional images, collages and movies. The system, one of the successors of Karl Sims...
Kinetics of proton uptake and dye binding by photoactive yellow protein in wild type and in the E46Q and E46A mutants.

We studied the kinetics of proton uptake and release by photoactive yellow protein (PYP) from Ectothiorhodospira halophila in wild type and the E46Q and E46A mutants by transient absorption spectroscopy with the pH-indicator dyes bromocresol purple or cresol red in unbuffered solution. In parallel, we investigated the kinetics of chromophore protonation as monitored by the rise and decay of the blue-shifted state I2 (λmax = 355 nm). For wild type the proton uptake kinetics is synchronized with the fast phase of I2 formation (τ = 500 μs at pH 6.2). The transient absorption signal from the dye also contains a slower component which is not due to dye deprotonation but is caused by dye binding to a hydrophobic patch that is transiently exposed in the structurally changed and partially unfolded I2 intermediate. This conclusion is based on the wavelength, pH, and concentration dependence of the dye signal and on dye measurements in the presence of buffer. SVD analysis, moreover, indicates the presence of two co...
Basic surgical instruments and their use

A surgical training program is much like an apprenticeship in which knowledge is passed from the skilled surgeon to the more junior. Often in learning these skills, certain nuances are assumed. The names and uses of surgical instruments are often not included in any surgical dialogue. This publication will hopefully clear up knowledge gaps in surgical positioning, instruments, and techniques. It is certainly not a treatise but aims to stimulate interest and enthusiasm for basic surgical principles.
The slow axisymmetric motion of two bubbles in a thermal gradient

Abstract The motion of two bubbles along their line of centers in an imposed thermal gradient is considered. The governing equations are solved in the quasistatic limit using bipolar coordinates. Representative streamlines and isotherms are presented. A simple heuristic approximation is also presented, and is found to be excellent over the entire range of values of the radius ratio and the separation distance. As expected, the interaction effect between two bubbles increases as the separation distance is decreased. A small bubble moves more rapidly in the presence of a larger bubble than in its absence, whether it leads or trails the larger bubble. The velocity of the large bubble is reduced compared to the case when it is isolated, but to a lesser extent. When the bubbles are of equal diameter, they exert no influence on each other's velocity for all separation distances.
Effects of pectinolytic yeast on the microbial composition and spoilage of olive fermentations.

This study resulted in the identification of pectinolytic yeasts in directly brined Sicilian-style green olive fermentations and examination of the influence of those yeasts on the microbial composition and quality of fermented olives. Firstly, defective olives processed in Northern California from 2007 to 2008 and characterized by high levels of mesocarp tissue degradation were found to contain distinct yeast and bacterial populations according to DNA sequence-based analyses. Strains of (pectinolytic) Saccharomyces cerevisiae, Pichia manshurica, Pichia kudriavzevii, and Candida boidinii isolated from directly brined olives were then inoculated into laboratory-scale olive fermentations to quantify the effects of individual yeast strains on the olives. The pH, titratable acidity, and numbers of lactic acid bacteria (LAB) and yeasts varied between the fermentations and fermentations inoculated with P. kudriavzevii and C. boidinii promoted the development of LAB populations. Olive tissue structural integrity declined significantly within 30, 74, and 192 days after the inoculation of pectinolytic S. cerevisiae, P. manshurica and C. boidinii, respectively. In comparison, tissue integrity of olives in control fermentations remained intact although pectinolytic yeasts were present. Notably, pectinolytic yeasts were not found in fermentations inoculated with (non-pectinolytic) P. kudriavzevii and olives exposed to a 1:1 ratio of P. kudriavzevii and P. manshurica exhibited no significant tissue defects. This study showed that pectinolytic yeast are important components of directly brined green olive fermentations and damage caused by pectinolytic yeasts might be prevented by other microbial colonists of the olives.
Psychophysics and Behavior

Resume 1. On decrit les fonctions stimulus-reponse pour trois sortes d'experiences “psycho-physiques.” 2. On discute la variable des reponses dans certaines de ces experiences. 3. On considere le probleme de description et d'explication comme il s'applique a l'experience “psycho-physique.”
Development of a reactive topical skin protectant

The use of a topical skin protectant (TSP) as a means of protecting troops from percutaneous chemical warfare agent (CWA) exposure has been proposed since these weapons were first used during World War I. The TSP is applied to vulnerable skin surfaces prior to entry into a chemical combat area. In 1990, the US Army Medical Research Institute of Chemical Defense transferred two non-reactive TSPs into advanced development. Following US Food and Drug Administration approval, the final product is expected to be available to soldiers in 1999. A continuing research effort is designed to develop a second-generation TSP that will increase effectiveness and also decontaminate CWAs into non-toxic products. We identified a list of 29 reactive moieties as potential additives to the TSP formulation. All candidate formulations are evaluated in a decision tree network, consisting of a series of 11 efficacy testing models. A prototype formulation (ICD 2701) containing the reactive ingredient S-330 has dramatically improved the protection against saturated sulfur mustard vapor. In addition, we have discovered a compound (ICD 2837) that significantly increases the skin’s natural resistance to CWA penetration. Our goal is to transfer a significantly improved TSP formulation into advanced development by 1999.
Comparative studies of murine anionic and cationic arylsulfatase B

Murine brain possesses an anionic form of arylsulfatase B which accounts for approximately 12–16% of nonmicrosomal arylsulfatase activity. This isozyme is antigenically similar to cationic arylsulfatase B, displays a similar developmental profile, and can be converted to a form resembling the cationic species by prior treatment with neuraminidase.
Mathematical Modeling of Ligaments and Tendons

Ligaments and tendons severe a variety of important functions in maintaining the structure of the human body. Although aboundant literature exists describing experimental investigations of these tissues, mathematical modeling of ligaments and tendons also contributes significantly to understanding their behavior. This paper presents a survey of developments in mathematical modelling of ligaments and tendons over the past 20 years. Mathematical descriptions of ligaments and tendons are identified as either elastic or viscoelastic, and are discussed in chronological order
Caspase‐3 activation in oligodendrocytes from the myelin‐deficient rat

The myelin-deficient (MD) rat has a point mutation in its proteolipid protein (PLP) gene that causes severe dysmyelination and oligodendrocyte cell death. Using an in vitro model, we have shown that MD oligodendrocytes initially differentiate similarly to wild-type cells, expressing galactocerebroside, 2′,3′-cyclic nucleotide 3′-phosphodiesterase, and myelin basic protein. However, at the time when PLP expression would normally begin, the MD oligodendrocytes die via an apoptotic pathway involving caspase activation. The active form of caspase-3 was detected, along with the cleavage products of poly-(ADP-ribose) polymerase (PARP) and spectrin, major targets of caspase-mediated proteolysis. A specific inhibitor of casapse-3, Ac-DEVD-CMK, reduced apoptosis in MD oligodendrocytes, but the rescued cells did not mature fully or express myelin-oligodendrocyte glycoprotein. These results suggest that mutant PLP affects not only cell death but also oligodendrocyte differentiation. J. Neurosci. Res. 64:371–379, 2001. © 2001 Wiley-Liss, Inc.