cssi/SciSciGPT-SciSciNet huggingface dataset:
PEAN: A Probabilistic Energy Aware Neighbor Monitoring Protocol for Mobile Ad Hoc Networks

This paper presents a novel application of the wake-up based power management protocol. MAC layer power management protocols have been studied for years. The power management mechanism which exploits the IEEE 802.11 power saving mode to save energy by turning on/off the network interface card is called the wake-up based power management. The previous proposals for the wake-up based power management focus on the network operations and neighbor discovery. In this paper, we apply the wake-up based power management to neighbor monitoring in securing mobile ad hoc networks (MANETs). We propose a probabilistic wake-up based power management protocol for neighbor monitoring which aims to reduce energy consumption while preserving the effectiveness of misbehaving node detection. We show by analysis and simulation the relation between the wake-up probability and the misbehavior detection rate.
Two New Peruvian Species of Draba (Brassicaceae)

Abstract. Draba beltranii and D. werffii (Brassicaceae) are described from the Peruvian departments of Lima and Arequipa, respectively. Draba beltranii differs from the related D. cuzcoensis and D. soratensis by having more ovules per ovary (30–34 vs. 14–26) and longer fruits and pedicels, and from the former by the bracteate raceme and from the latter by the yellow instead of white flowers. Draba werffii differs from all South American species by a combination of small (2.5–3.0 × 0.7–1.0 mm), blue or purple flowers, scapose habit, and ebracteate racemes.
Schema-based learning of adaptable and flexible prey-catching in anurans I. The basic architecture

A motor action often involves the coordination of several motor synergies and requires flexible adjustment of the ongoing execution based on feedback signals. To elucidate the neural mechanisms underlying the construction and selection of motor synergies, we study prey-capture in anurans. Experimental data demonstrate the intricate interaction between different motor synergies, including the interplay of their afferent feedback signals (Weerasuriya 1991; Anderson and Nishikawa 1996). Such data provide insights for the general issues concerning two-way information flow between sensory centers, motor circuits and periphery in motor coordination. We show how different afferent feedback signals about the status of the different components of the motor apparatus play a critical role in motor control as well as in learning. This paper, along with its companion paper, extend the model by Liaw et al. (1994) by integrating a number of different motor pattern generators, different types of afferent feedback, as well as the corresponding control structure within an adaptive framework we call Schema-Based Learning. We develop a model of the different MPGs involved in prey-catching as a vehicle to investigate the following questions: What are the characteristic features of the activity of a single muscle? How can these features be controlled by the premotor circuit? What are the strategies employed to generate and synchronize motor synergies? What is the role of afferent feedback in shaping the activity of a MPG? How can several MPGs share the same underlying circuitry and yet give rise to different motor patterns under different input conditions? In the companion paper we also extend the model by incorporating learning components that give rise to more flexible, adaptable and robust behaviors. To show these aspects we incorporate studies on experiments on lesions and the learning processes that allow the animal to recover its proper functioning
Ecological laws: what would they be and why would they matter?

There remains considerable debate over the existence of ecological laws. However, this debate has not made use of an adequate account of what a relationship would have to be like in order for it to qualify as an ecological law. As a result, confusions have persisted not only over how to show that ecological laws do (or do not) exist, but also regarding why their existence would matter – other than to whether ecology looks like physics. I argue that ecological laws would have to possess collectively a distinctive kind of invariance under counterfactual perturbations. I call this invariance “stability.” A law of physics, such as the law that all bodies travel no faster than the speed of light, is not only true, but also necessary in a physically significant sense. (A body must travel no faster than light; it couldn't do otherwise, even if it were subjected to a greater force.) Likewise, the stability of ecological laws would render them necessary in an ecologically relevant sense. Furthermore, ecological laws would differ from fundamental laws of physics in the range of counterfactual perturbations under which they are invariant. Therefore, I argue, the existence of ecological laws would make ecological explanations irreducible to even the most complete possible physical explanations of the same phenomena. Ecological laws would make ecology genuinely autonomous from physics.
How does petroleum price and corn yield volatility affect ethanol markets with and without an ethanol use mandate

The recent increase in ethanol use in the US strengthens and changes the nature of links between agricultural and energy markets. Here, we explore the interaction of market volatility and the scope for policy to affect this interaction, with a focus on how corn yields and petroleum prices affect ethanol prices. Mandates associated with new US energy legislation may intervene in these links in the medium-term future. We simulate stochastically a structural model that represents these markets, and that includes mandates, in order to assess how shocks to corn or oil markets can affect ethanol price and use. We estimate that the mandate makes ethanol producer prices more sensitive to corn yields and less sensitive to changes in petroleum prices overall. We note a discontinuity in these links that is caused by the mandate. Ethanol use can exceed the mandate if petroleum prices and corn yields are high enough, but the mandate limits downside adjustments in ethanol use to low petroleum prices or corn yields.
Altered brain mitochondrial metabolism in healthy aging as assessed by in vivo magnetic resonance spectroscopy

A decline in brain function is a characteristic feature of healthy aging; however, little is known about the biologic basis of this phenomenon. To determine whether there are alterations in brain mitochondrial metabolism associated with healthy aging, we combined 13C/1H magnetic resonance spectroscopy with infusions of [1-13C]glucose and [2-13C]acetate to quantitatively characterize rates of neuronal and astroglial tricarboxylic acid cycles, as well as neuroglial glutamate–glutamine cycling, in healthy elderly and young volunteers. Compared with young subjects, neuronal mitochondrial metabolism and glutamate–glutamine cycle flux was ~30% lower in elderly subjects. The reduction in individual subjects correlated strongly with reductions in N-acetylaspartate and glutamate concentrations consistent with chronic reductions in brain mitochondrial function. In elderly subjects infused with [2-13C]acetate labeling of glutamine, C4 and C3 differed from that of the young subjects, indicating age-related changes in glial mitochondrial metabolism. Taken together, these studies show that healthy aging is associated with reduced neuronal mitochondrial metabolism and altered glial mitochondrial metabolism, which may in part be responsible for declines in brain function.
Atomic Force Microscopy Study of Anodic Etching of Aluminum: Etching Morphology Development and Caustic Pretreatment

Atomic force microscopy (AFM) was used to investigate the topographic characteristics of pitting sites during anodic galvanostatic etching of high-purity aluminum foils in hot baths containing HCI and H 2 SO 4 . Pit sites near pre-existing ridges formed by rolling are preferred, and the distribution of sites depends on the foil fabrication process. Etch tunnels are found only within shallow pits formed by surface dissolution, which may be a prerequisite for tunnel formation. Pit sites are more numerous and evenly distributed after pretreatment of foils by immersion in 1 N NaOH. AFM imaging during acid dissolution of NaOH treated foils reveal submicrometer cavities formed as a result of NaOH treatment. Some cavities appear to form near oxide particles or inclusions. It is argued that these cavities are subsurface voids exposed by uniform dissolution in the acid. If the void surface is oxide-free, they may dissolve as pits when exposed by the shallow surface dissolution shown to take place in the etchant bath.
Effects of Pore Structure in Nitrogen Functionalized Mesoporous Carbon on Oxygen Reduction Reaction Activity of Platinum Nanoparticles

Abstract Nitrogen-doped mesoporous carbons (NMCs) with ordered to disordered pore structures were fabricated on SBA-15 modified with different concentrations of tetraethyl orthosilicate using pyrrole as a carbon source. The carbonization temperature of NMCs was maintained at 800 °C so that the amount and type of nitrogen functionalities were constant. Pt nanoparticles (NPs) were deposited onto NMCs using a modified polyol process. N2 adsorption isotherms, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy were used to characterize NMCs and Pt NPs. A significant shift in binding energy was found in Pt NPs deposited on NMC with disordered pore structure compared to Pt NPs deposited on NMC with ordered pore structure. Pt NPs deposited on NMC with the disordered pore structure had the highest intrinsic oxygen reduction reaction (ORR) activity among the Pt/NMC catalysts. It showed that the interaction between Pt NPs and NMCs could be modulated for enhancement of the ORR activity of Pt NPs by changing the pore structure of NMCs.
Generalized linear recursive networks: topological and routing properties

Abstract This paper presents a methodology for generalizing the class of linear recursive networks (LRN) reported by Hsu et al. [IEEE Trans Parallel Distrib Syst 1997; 8(7)]. The proposed generalization relaxes the restriction on the number of isomorphic subgraphs of LRNs, which is at most 1 by Hsu et al. [IEEE Trans Parallel Distrib Syst 1997; 8(7)]. Hence, our methodology permits the design of a communication topology of size n which satisfies the linear recurrence equation Gn(A)=a1Gn−1(A)∪a2Gn−2(A)∪⋯∪akGn−k(A), with aj being any non-negative integer for each j∈{1,2,…,k} and a1>0. In addition, we address the problem of routing of messages in an generalized linear recursive network (GLRN). The paradigm of Fibonacci cubes (FCs) is used to demonstrate the proposed technique. FCs were introduced recently as an attractive alternative to the well-known hypercube model for interconnection networks. A generalized FC, referred to as a “Fibonacci graph” (FG) of size n, is composed of an arbitrary number of such graphs of size n−1 and size n−2. The structural advantage of GLRNs, in general, and FG, in particular, manifests itself in the following ways: 1. They allow more choices to construct systems of various sizes. 2. They emulate other topologies, such as hypercubes, trees, rings and meshes very efficiently. The results of this paper have important applications e.g. in multitasking and job scheduling where a job is decomposed into a set of tasks and assigned to a subset of processors with specified interconnection topology.
SU‐FF‐J‐15: A Retrospective Study of the Variation in Organ Dose as a Function of Table Shifts Using Megavoltage Cone‐Beam CT

Purpose: This study analyzes the variation in patient setup based upon daily megavoltage cone‐beam CT (MVCBCT) prior to treatment. The variation in organ dose as a function of table shifts is quantified in order to understand the effect of systematic versus random setup error for head and neck (H&N) IMRT patients. Methods and Materials: Sixty patients with H&N cancer were imaged on a daily basis prior to treatment using MVCB CTimaging with the initial clinical setup based upon in‐room lasers and mask marks. After imaging the patients were repositioned based upon registration of the MVCB CT to the original planning CT. The average shift, standard deviation and root mean square values were calculated based upon the daily shift values in the lateral (LAT), superior‐inferior (LONG), and anterior‐posterior (VERT) dimensions. The mean shift values were incorporated into the treatment planning system to recalculate the dosimetry for each patient, assuming the shifts were not performed on a daily basis. Results: Comprehensive tables were generated to evaluate the dose difference for each patient as a function of the CTV, spinal cord, and optic chiasm assuming the mean table shift values were not performed on a daily basis. The maximum and mean dose difference for the CTV, averaged across nine patients in the study group, was −4.0% (range of −9.5% to 0.5%) and −5.7% (range of −11.7% to 0.2%). The maximum and mean dose difference for the spinal cord was −3% (range of −12.4% to 13.6%) and −6.1% (range of −12.9% to 1.2%). Conclusion: The dosimetry difference is not trivial before and after table shifts based upon MVCB CTimaging. Further study is needed to quantify the effect on the delivered dose distribution as a function of systematic versus random setup error.
Faces of Fatherhood: African American Young Adults View the Paternal Role

Narrative analysis of semistructured interviews with 64 young adults (98% African American) revealed their idealized views of biological fathers. Interviews contained descriptions of current father contacts as well. Data were informed by prospective quantitative information on fatherchild contact from infancy to age 15. Ideally, biological fathers give children personal presence, material support, counsel, and guidance. Each relationship was classified as either: deceased, unknown, known but not involved, or involved; analysis showed that the extent of early contact tended to predict these categories. These findings have implications for practitioners and service providers working with African American children, families, and communities.
Sterile Anesthesia Breathing Circuits Do Not Prevent Postoperative Pulmonary Infection

In a prospective, randomized trial, the effectiveness of sterile anesthesia breathing circuits having bacterial filters in decreasing the incidence of postoperative pulmonary infection was evaluated. Two hundred ninety-three patients undergoing major surgical procedures were assigned randomly to receive anesthetics through a sterile, disposable circuit having a bacterial filter, or a reusable circuit that had been washed and dried after previous use. The two groups were well matched for age, sex, type of surgical procedure, type of anesthetic, and history of smoking or obstructive lung disease. A physician observer, who was unaware of these assignments, reviewed the patients' post-operative status for evidence of pulmonary infection. The over-all rate of infection was 3.5 per cent; no significant difference in the rates of infection occurred between the two groups. Five (3.6 per cent) of the 138 patients anesthetized with sterile circuits had postoperative respiratory infection, compared with four (2.6 per cent) of the 155 patients anesthetized with unsterile circuits. In both groups, maximum postoperative temperature, white-blood-cell count, and the lowest values for arterial oxygen tension were similar. The authors therefore conclude that when simple hygienic measures are followed, the routine use of sterile anesthesia breathing circuits with bacterial filters does not decrease the risk of postoperative infection.
Demographics of Bench Level Automotive Electrical and Electromagnetic Compatibility Validation Test Laboratories

Bench level testing is an important process that gives an early indication of the performance that components and subsystems will have when installed in a system that is required to operate in a given environment. With the increase in the number of electrical components and subsystems in modern vehicle systems, supplier and commercial test labs have been leveraged to perform much of this testing. The amount of time, the cost, and the quality of the test services provided are related to the number of available qualified labs and the experience of the employees. This paper summarizes the demographics of bench level electrical and electromagnetic compatibility validation test laboratories. The various qualifications available for validation test laboratories and their employees are discussed. The population of supplier and commercial validation laboratories and their locations are presented. A survey was performed to gain an understanding of the experience level of employees that work at the available validation labs. The employees representing the participating laboratories have a tremendous amount of experience. This information increases confidence in the ability for the test laboratories to provide quality results in a cost efficient and timely manner. Index Terms—demographics, bench, component, subsystem, electromagnetic compatibility, EMC, PPAP, validation, test, laboratory, ISO/IEC 17025, accreditation, ILAC, iNARTE, recognition I. INTRODUCTION Electrical and electromagnetic compatibility (EMC) testing performed on individual components or subsystems is critical in order to validate their robustness to the operating and environmental conditions that they may be subjected to in the field. Automotive original equipment manufacturers (OEMs) and suppliers of electrical or electronic components leverage available qualified laboratories around the world to perform this testing as a part of the Production Part Approval Process (PPAP) validation consistent with ISO/IEC 16949 (1). The time, cost, and quality of validation tests are related to the number of available qualified labs in the area that can perform the required tests and the experience of the employees. This paper explores these factors and how they relate to the validation process.
Formaldehyde: Abinitio MCSCF+CI transition state for H2CO → CO+H2 on the S0 surface

Ab initio multiconfiguration self‐consistent field (MCSCF) and configuration interaction (CI) calculations have yielded an activation energy of 80.9±3.0 kcal/mol for the dissociation of formaldehyde to H2 and CO on the ground state potential energy surface. The error limits are estimates based on an analysis of the effects of one‐particle basis set, electron correlation, and transition state structure on the activation energy. Accurate structures and harmonic frequencies are presented for H2CO (X 1A1) and the transition state.
Sleep and Brain Development

Abstract Sleep and sleep cycles begin at around 26 to 28 weeks' gestational age. They were originally recognized by observing infant behaviors. This observation of behaviors and changes in physiology has now added electoenchephalography (EEG) and continuous electoenchephalography (aEEG) to the studies of sleep and sleep cycles. Sleep partitions from indeterminate sleep EEG patterns to quiet sleep or non–rapid eye movement (REM) sleep, REM sleep, and quiet awake intervals. The REM sleep follows the quiet or slow wave sleep in the cycles. Sleep and sleep cycles are essential for the development of the neurosensory and motor systems in the fetus and neonate. They are essential for the creation of memory and long-term memory circuits, and they are essential for the maintenance of brain plasticity over the lifetime of the individual. The importance of sleep and preservation of sleep cycles in infants has been known for more than 40 years. They are critical for the fetus in utero and the preterm infant in the newborn intensive care unit (NICU). The infants' state and sleep-wake cycles have been studied as part of developmental care since the 1980s. A major part of the implementation of developmentally appropriate care involves using the infant state and cues to plan care and interventions. This is also essential for the preservation of sleep and sleep cycles that are essential for early neurosensory development. Interference with sleep and disruption of sleep cycles can significantly interfere with the early processes of sensory development. Parents are playing an increasingly important role in supporting early development.
Automatic Switching of AC Power in Larger Telephone Exchanges Equipped with Standby Generating Equipment

A concept of switchgear with drawout air circuit breakers used as transfer equipment between commercial utility power and a stand-by power plant is described. The advantages of drawout type air circuit breakers are discussed over the use of commercially available automatic transfer switches. This applies especially to larger exchanges in metropolitan areas. Pictures of actual installations are included to show physical arrangements of transfer breakers and distribution breakers in different combinations. Single line schematics of the equipment shown in the photos are also included. In the second half of the paper the transfer breaker concept is developed further, and the emphasis is on control coordination between the switchgear and the diesel engine or turbine generator system, so that the switchgear and the stand-by power service become a controlled entity with emphasis on ultimate reliability of the AC power in an unattended environment. In conclusion, multi-engine systems are discussed with their special control requirements: Automatic and manual engine generators on common bus, bus systems with tie breakers when used with multiple automatic stand-by sets, as well as multiple units with automatic synchronizing features and their special control considerations. Again, single line diagrams are used to show the systems discussed.
The specific heat of linear polyethylene after annealing at low temperatures

After annealing at low temperature, linear polyethylene displays an unusual feature in its specific heat curve. On heating, a maximum is observed just above the annealing temperature. The magnitude of this excess specific heat is dependent on the initial level of crystallinity and the temperature and time of annealing. The maximum does not reappear on subsequent cooling followed by rapid heating and represents the formation and disappearance of an unstable structure. These results can be interpreted as a crystallization-melting phenomenon and are consistent with the wide-angle x-ray diffraction patterns. The optimum effects are observed in the β-region (−50°C to 0°C) and could possibly lead to complications in interpreting other phenomena in this temperature range.
Polar organic oxygenates in PM2.5 at a southeastern site in the United States

Abstract A field study was undertaken in Research Triangle Park, NC, USA during the summer of 2000 to identify classes of polar oxygenates in PM 2.5 containing carbonyl and/or hydroxyl functional groups and, to the extent possible, determine the individual particle-bound oxygenates that make up each class. The selected site was in a semi-rural environment with expected impacts from both biogenic and anthropogenic sources. PM 2.5 samples were collected and analyzed for gravimetric mass, inorganic composition by ion chromatography, polar oxygenated compounds by gas chromatography-mass spectroscopy after derivatization of the solvent extracts, organic and elemental carbon (EC) by a thermal–optical method, and chemical functional groups by infrared (IR) spectroscopy. The chemical analyses also included determining the polarity of the PM 2.5 by measuring the organic carbon (OC) concentrations in a series of extraction solvents of increasing polarity. The ambient PM 2.5 mass concentrations ranged between 9 and 30 μg m −3 , with an average mass composition of 28% sulfate, 6% nitrate, 12% ammonium, 39% OC compound, 2% EC, and 12% liquid water at a relative humidity of 43%. OC analyses of the organic extracts indicated approximately 89% of the extractable OC was more polar in nature than that extracted by n -hexane. IR analysis of the PM 2.5 was consistent with the presence of significant levels of polar carbonyl and hydroxyl functional groups. The polar nature of the organic fraction was further supported by the observation that the inorganic fraction accounted for only about 80% of measured liquid water concentrations in the PM 2.5 . The mass spectra data were consistent with the presence of the following classes of oxygenates: oxo monocarboxylic acids, trihydroxy monocarboxylic acids, dihydroxy dicarboxylic acids, hydroxy dicarboxylic acids, normal dicarboxylic acids, oxo dicarboxylic acids, methoxy dicarboxylic acids, tricarboxylic acids, triols, and photooxidation products of α -pinene and toluene. In particular, five secondary organic aerosol compounds observed in a smog chamber irradiation of an α -pinene/NO x /air mixture were detected in ambient PM 2.5 .
Reactive transport of metal contaminants in alluvium—model comparison and column simulation

Abstract A comparative assessment of two reactive-transport models, PHREEQC and HYDROGEOCHEM (HGC), was done to determine the suitability of each for simulating the movement of acidic contamination in alluvium. For simulations that accounted for aqueous complexation, precipitation and dissolution, the breakthrough and rinseout curves generated by each model were similar. The differences in simulated equilibrium concentrations between models were minor and were related to (1) different units in model output, (2) different activity coefficients, and (3) ionic-strength calculations. When adsorption processes were added to the models, the rinseout pH simulated by PHREEQC using the diffuse double-layer adsorption model rose to a pH of 6 after pore volume 15, about 1 pore volume later than the pH simulated by HGC using the constant-capacitance model. In PHREEQC simulation of a laboratory column experiment, the inability of the model to match measured outflow concentrations of selected constituents was related to the evident lack of local geochemical equilibrium in the column. The difference in timing and size of measured and simulated breakthrough of selected constituents indicated that the redox and adsorption reactions in the column occurred slowly when compared with the modeled reactions. MINTEQA2 and PHREEQC simulations of the column experiment indicated that the number of surface sites that took part in adsorption reactions was less than that estimated from the measured concentration of Fe hydroxide in the alluvium.
Transforming growth factor-β2 is involved in quantitative genetic variation in thymic involution

The mechanisms regulating thymic involution are unclear. In inbred mouse strains the rate of thymic involution and the function of the hematopoietic stem cell (HSC) compartment are subject to quantitative genetic variation. We have shown previously that transforming growth factor-β2 (TGF-β2) is a genetically determined positive regulator of HSCs. Here, we demonstrate that genetic variation in the rate of thymic involution correlates with genetic variation in the responsiveness of hematopoietic stem and progenitor cells to TGF-β2. Corroborating these correlations, thymic cellularity and peripheral naive T-cell frequency were higher in old Tgfb2+/- mice than in wild-type littermates. The frequency of early T-cell precursors was increased in Tgfb2+/- mice, suggesting that TGF-β2 affects the earliest stages of T-cell development in old mice. Reciprocal transplantation experiments indicated that TGF-β2 expressed both in the (micro)environment and in the hematopoietic system can accelerate thymic involution; however, the age of the stem cells appeared irrelevant. Thus, although thymic involution is largely determined by the aged environment, TGF-β2 plays a major modulatory role that is subject to genetic variation and is possibly mediated through its regulatory effects on early hematopoiesis.
Strategy, size of firm, and the use of technical alliances: An explanatory study

Abstract This paper describes an explanatory study of business strategy, size of firm, and the use of technical alliances in a sample of 52 semiconductor firms. The study seeks to view and understand technical alliances not in terms of when a firm chooses to engage in a particular kind of technical alliance, as much of the literature does, but in terms of the magnitude and importance of technical alliances in a firm's strategy and the factors that determine this. The use of technical alliances is pervasive across Porter's generic strategies and across emerging and mature product and process technologies. Both nonusers and firms spending the highest percentage of their R & D budgets on technical alliances tend to have strategies emphasizing technically unique products. Spending on consortia research varies significantly by size of firm, with small firms spending the lowest percentage of their R & D budgets on consortia research. The data suggest that firms may still be experimenting with technical alliances and that present usage patterns may not be stable. Hypotheses aredeveloped and directions for future research are proposed.
Computational analysis of the effect of welding parameters on energy consumption in GTA welding process

Abstract The electrical energy needed in welding processes is a major factor of energy consumption in manufacturing processes that use welds to fabricate structures. In the arc welding process an intense electrical arc is used as the heat source to melt locally metallic materials to join them once they solidify. Although the arc is focused at the joint, a large portion of energy is dissipated as heat through the base metals to the surroundings. In this paper it is shown that selecting the welding parameters appropriately, viz., the power supplied to the arc and the translation speed of the arc, can reduce the energy consumed per unit length of weld. The range of parameters examined was selected such that the vaporization of the molten metal was negligible. It is shown that increasing the arc power in conjunction with increasing the travel speed of the arc leads to reduced energy consumption per unit length of weld; this reduction in energy consumption is for equivalent welds, i.e., welds with identical geometric features.
Resonance Raman Spectra of Ferrochelatase Reveal Porphyrin Distortion upon Metal Binding

Ferrochelatase catalyzes Fe2+ insertion into porphyrins, and is inhibited by Hg2+. Resonance Raman spectra of mesoporphyrin IX show that binding to ferrochelatase restricts the conformation of the propionate side chains, but does not perturb the ring conformation. However, a pronounced perturbation is seen in the ternary complex with Hg2+. Several additional RR bands are activated, including some arising from IR-active vibrations, establishing loss of an effective symmetry center. Out-of-plane modes appear in the low frequency region. The strongest of these bands, γ5 and γ6, correspond to pyrrole tilting vibrations, which are in the same symmetry class as a doming distortion of the porphyrin. All four pyrrole N atoms are pointing toward the same side of the porphyrin plane, a geometry expected to facilitate Fe2+ insertion. This distortion is proposed to result from occupation of a metal-binding site, proximate to the prophyrin, which promotes insertion of Fe2+, while occupation by Hg2+ is inhibitory.
Comparing Influences on Peruvian Climate Change Policy: Information, Knowledge, and Concern Among Political Elites

Climate change is considered as the most important contemporary global environmental problem. Despite research efforts from the social sciences to understand how individuals perceive the problem, few studies have focused on policy makers, specially in developing countries. This study seeks to determine the similarities and differences between elite government groups in Peru. It focuses on the knowledge about climate change, environmental concern, and sources of policy information, and how these factors affect policy preferences. Studies in other countries reveal that these factors can influence both the prioritization of environmental policy issues and the content of policy proposals.
Dietary self-selection and meal patterns of obese and lean Zucker rats.

Following two weeks of baseline measures on laboratory chow, young obese and lean male Zucker rats were given access to separate macronutrients for 18 weeks. First, the rats were given access to soybean meal, dextrinized starch, and lard for eight weeks. Daily caloric intake of obese rats was greater on laboratory chow than that of lean rats and remained so following the switch to the self-selection diet. While obese and lean rats consumed similar proportions of each macronutrient over the eight-week period, there were substantial changes in the pattern of intake across weeks. Obese rats decreased daily caloric intake primarily by decreasing lard consumption. In contrast, lean rats maintained daily caloric intake while increasing the proportion of calories from fat. The addition of a 25% sucrose solution (weeks 11–18) produced an elevated daily caloric intake for both obese and lean rats, achieved through an increased carbohydrate intake with a simultaneous decrease in fat intake. A diurnal pattern of intake was maintained for each macronutrient. Compared to controls, rats on the self-selection diet did not show differential growth. Measurement of daily meal patterns for soybean meal, sucrose, and lard during the last four days of the experiment showed that obese rats ate significantly larger meals comprised of all three food components than did lean rats. For both obese and lean rats, one-component meals were primarily sucrose with greater intake during the light period. Lean rats showed a greater tendency to indulge in these between-meal “snacks” than did obese rats. These data suggest that palatability and nutrient source as well as length of exposure are critical determiners of nutrient selection and total daily caloric intake.
Influence of molecular weight distribution on the linear viscoelastic properties of polymer blends

Literature data for the dynamic viscoelastic properties of binary blends of nearly monodisperse polybutadienes, polystyrenes, and poly(methyl methacrylate)s was analyzed using logarithmic plots of dynamic storage modulus G′ versus loss modulus G″, based on a recent theoretical study by Han and John.28 It has been found that for binary blends of monodisperse polymers with molecular weights M much greater than the entanglement molecular weight Me, the value of G′ in log G′ − log G″ plots becomes independent of molecular weight, increases sharply as small amounts of a high-molecular-weight component are added to a low-molecular-weight component, and passes through a maximum G′max at a critical blend composition (ϕ2)max, and that G′max becomes larger and (ϕ2)max becomes smaller as the ratio of component molecular weights increases. However, as the molecular weight distribution of the constituent components becomes broader, the effect of blend composition on G′ in log G′ − log G″ plots becomes less pronounced. This observation has enabled us to explain why log G′ − log G″ plots of binary blends of commercial polymers, namely, blends of two low-density polyethylenes, blends of poly(ϵ-caprolactone) and poly(styrene-co-acrylonitrile), and blends of poly(methyl methacrylate) and poly(vinylidene fluoride), all having broad molecular weight distributions, give rise to values of G′ between those of the constituent components. When one of the constituent components has molecular weight smaller than Me, while the other has molecular weight larger, and as small amounts of the high-molecular-weight component are added to the low-molecular-weight component, log G′ − log G″ plots of binary blends give rise to values of G′ larger than those of the constituent components at low values of G″, but approaches the value of G′ for the low-molecular-weight component as the value of G″ is increased. However as the amount of the high-molecular-weight component is increased above a certain critical composition, binary blends give rise to values of G′ close to that of the high-molecular-weight component at all values of G″. The experimentally observed dependence of G′ on blend composition in log G′ − log G″ plots is favorably compared to the theoretical prediction of a blending law proposed by Montfort and co-workers.14,15
The synthesis of racemic tremetone

Tremetone (I), the principal toxic ketone from Eupatorium urticaefolium, has been synthesized in its racemic form by the following sequence of reactions: 2-acetyl-2,3-dihydrobenzofuran (VIII)—(MeMgI)→2-(2′,3′-dihydro-2′-benzofuryl)-2-propanol (XIII)—((F3CCO)2O-HOAc)→2-(5′-acetyl-2′,3′-dihydro-2′-benzofuryl)-2-propyl acetate (XVII)—(H2O, OH−)→2-(5′-acetyl-2′,3′-dihydro-2′-benzofuryl)-2-propanol (XVIII)—(−H2O) → I.
Partitioned Scheduling of P-FRP in Symmetric Homogenous Multiprocessors

Functional Reactive Programming (FRP) is a declarative approach to modeling and building reactive systems. Priority-based FRP (P-FRP) has recently been introduced as a FRP formalism that guarantees real-time response. P-FRP guarantees that when a higher priority task is released, the system will immediately preempt any executing lower-priority tasks. To maintain guarantees of state-less execution offered by the functional programming model, P-FRP implements a transactional nature of execution. Each higher priority event in P-FRP can abort a lower priority task forcing it to restart. Existing work on partitioning tasks in multi-processor systems have been focused on the classical preemptive model of execution1. However, due do its transactional nature, the schedulability tests used in the partitioning algorithms for the preemptive model, cannot be applied 'as is' to the P-FRP execution model. While multiprocessor response time analysis of P-FRP has been done in previous work, partitioning schemes for tasks in multi-processor systems have not been presented yet. In this paper, we present an exact schedulability test for P-FRP and use it in two existing first-fit partitioning schemes. We also introduce a new first-fit partitioning scheme based on the processing time of tasks, which yields better results than the other two schemes. We also show that the number of processors required to schedule tasks in P-FRP are more than or equal to the number of processors required to schedule the same in the preemptive model.
Cavity ring-down spectroscopy for atmospheric trace gas detection: application to the nitrate radical (NO 3 )

Cavity ring-down spectroscopy is a relatively new and quite sensitive technique for the measurement of gas-phase optical extinction. It holds the potential for simple, direct and sensitive measurement of the concentrations of a variety of trace gases in the atmosphere. For example, detection of the nitrate radical, NO3, and its companion, dinitrogen pentoxide, N2O5, has been demonstrated with a sensitivity of 0.25 pptv (1σ). This paper considers several of the requirements for the application of cavity ring-down spectroscopy to concentration measurements of trace gases in ambient air. These include detection sensitivity, measurement of an accurate zero in the presence of competing absorbers, cavity stability and mirror cleanliness, laser line-width effects, saturation effects, Rayleigh scattering, the influence of atmospheric aerosols and sampling issues for reactive species. Examples drawn from our work on NO3 and N2O5 detection in the field illustrate these considerations.
Is there a role for curative surgery for pelvic recurrence from rectal carcinoma in the presence of hydronephrosis

Abstract Background: The prognosis for patients with recurrent rectal adenocarcinoma is not uniformly fatal if one can safely and selectively reoperate on a subset of patients with resectable disease. Even with careful selection, many patients undergo exploratory laparotomy and do not have resectable disease. We have reported that the presence of hydronephrosis in the setting of recurrent rectal carcinoma portends a poor outcome because of invariable association with unresectable disease. The purpose of this study was to update our experience of patients presenting with unilateral or bilateral hydronephrosis and recurrent rectal cancer. Methods: A retrospective chart review of 142 patients with recurrent rectal cancer evaluated at our institution from January 1989 to December 1999 was performed. Results: Twenty-seven of 142 patients referred for the management of recurrent rectal cancer had unilateral or bilateral hydronephrosis. Fifteen (55%) of these patients had distant metastatic disease. Twelve patients (45%) with hydronephrosis and local recurrent disease on evaluation were analyzed. Six of the 12 patients underwent exploratory laparotomy, with none found to have resectable disease. Their mean survival after diagnosis of recurrent disease was 14 months. Conclusions: Based on our results, the presence of hydronephrosis (unilateral or bilateral) in recurrent rectal adenocarcinoma portends a survival equivalent to the presence of distant metastasis. Therefore, we do not believe potential curative surgery has a role for patients with locally recurrent rectal adenocarcinoma in the presence of hydronephrosis.
A model composition of the basaltic achondrite planetoid

The basaltic achondrites, eucrites, diogenites, and howardites have compositions on a common oxygen isotope mass fractionation line and probably formed from a chondritic precursor also lying on that same line. No chondritic meteorite group has the same isotopic signature as the basaltic achondrites, so the oxygen isotope ratios of several known chondritic groups were used to construct a two component mixing model for the composition of the precursor. This model does not provide a unique solution, as several mixtures of ordinary and carbonaceous precursors will satisfy the isotopic constraints. The FeMnMg abundances of the precursors and of the eucrites were used to provide an additional constraint. The precursor composition selected for study is a mixture of 70% (wt) H-chondrite with 30% (wt) CM-chondrtte. This mixture generates a slightly FeO-rich silicate precursor that, after reduction and separation of an iron + sulfide core, is compatible with the mantle of the basaltic achondrite planetoid (BAP) having a similar composition to that modeled by Dreibus and Wanke (1980). Partial melting experiments of this H-CM precursor composition suggest that eucritic magmas could be formed in such a mantle. These experiments also suggest that the mantle must have experienced metal loss to constrain the Fe/Mn ratios and probably significant olivine fractionation as well. Diogenite precursors may also be generated in this mantle composition as FeO reduction and olivine fractionation lead to the formation of SiO2 enriched compositions from which diogenite source magmas may be extracted. If mixing of material from two very distinct chondritic reservoirs (H and CM-chondrites) is realistic, then an asteroid scale mixing process is needed to generate the achondrite precursor. Large impact events would provide a plausible method for mixing material from reservoirs with quite different oxygen isotope characteristics to assemble the basaltic achondrite planetoid.
Long-term biological effects of petroleum residues on fiddler crabs in salt marshes

Abstract In September 1969, the Florida barge spilled 700,000 L of No. 2 fuel oil into the salt marsh sediments of Wild Harbor (Buzzards Bay, MA). Today the aboveground environment appears unaffected, but a substantial amount of moderately degraded petroleum still remains 8–20 cm below the surface. The salt marsh fiddler crabs, Uca pugnax , burrow into the sediments at depths of 5–25 cm, and are chronically exposed to the spilled oil. Behavioral studies conducted with U. pugnax from Wild Harbor and a control site, Great Sippewissett marsh, found that crabs exposed to the oil avoided burrowing into oiled layers, suffered delayed escape responses, lowered feeding rates, and achieved lower densities. The oil residues are therefore biologically active and affect U. pugnax populations. Our results add new knowledge about long-term consequences of spilled oil, a dimension that should be included when assessing oil-impacted areas and developing management plans designed to restore, rehabilitate, or replace impacted areas.
The Empirical Basis of Dialectical Behavior Therapy: Summary, Critique, and Implications

The empirical literature offered in support and validation of Linehan's dialectical behavior therapy (DBT) is critically examined in this article. Although results to date are promising, there remain methodological difficulties in the limited research base that supports this eagerly received clinical approach to borderline personality disorder. Implications for clinical decision making are discussed and suggestions offered as to how future investigations can begin to better substantiate DBT as a thoroughly established clinical approach to treating this challenging disorder.
How parapsychology could become a science

An important methodological argument is outlined in support of general theoretical challenges to the dominant materialist paradigm. The idea is that the empirical inadequacies of a dominant theory can be hidden from view by various factors, and will emerge from the shadows only when viewed from the perspective of a systematic conceptual alternative. The question then posed is whether parapsychology provides a conceptual alternative adequate to this task. The provisional conclusion drawn is that it does not. Some further consequences are drawn from this concerning the experimental side of the parapsychological tradition.
The Use of Palatal Island Flaps as an Adjunct to Microvascular Free Tissue Transfer for Reconstruction of Complex Oromandibular Defects

Objective To determine the efficacy of using palatal island flaps in combination with free tissue transfer for reconstruction of large, complex oral cavity defects. Study Design Prospective evaluation of patients with large, combined defects of the oral cavity reconstructed with palatal flaps in conjunction with microvascular free tissue transfer. Methods Elevation of a palatal flap was performed after completion of tumor resection. The flap was rotated and secured into place. A free flap was then harvested and inset to reconstruct the remaining oromandibular defect. Free flaps included the rectus abdominis (6), fibula (16), and radial forearm (6). Results Large complex oral cavity defects were repaired with a palatal island flap in conjunction with microvascular free tissue transfer in 28 consecutive patients. There were no complications associated with this flap. Conclusion Maximal functional rehabilitation of large, complex oral defects requires independent reconstruction of the various regions of the oral cavity rather than single flap reconstruction. When used as an adjunct to free tissue transfer, the palatal island flap offers a reliable method for reconstructing large combination defects.