cssi/SciSciGPT-SciSciNet huggingface dataset:
Social Attitudes Predict Biases in Geographic Knowledge

Three principal components were found to underlie Texas university students' experiences with and attitudes toward Canada, the United States, and Mexico: diversity orientation, Mexican experiences, and Canadian experiences. Diversity orientation included positive attitudes toward Hispanics, Canadians, minorities, interethnic friendships, and dating and was negatively correlated with natio-centrism (e.g., believing U.S. citizens receive the world's best education). Diversity orientation and natio-centrism were not related to experiences with Mexico or Canada. Students estimated the locations of Canadian cities too far north and Mexican cities too far south. Biased estimates for Mexican cities were negatively correlated with diversity orientation, not experience with Mexico.
PCP: efficient endpoint congestion control

In this paper, we present the design, implementation, and evaluation of a novel endpoint congestion control system that achieves near-optimal performance in all likely circumstances. Our approach, called the Probe Control Protocol (PCP), emulates network-based control by using explicit short probes to test and temporarily acquire available bandwidth. Like TCP, PCP requires no network support beyond plain FIFO queues. Our initial experiments show that PCP, unlike TCP, achieves rapid startup, small queues, and low loss rates, and that the efficiency of our approach does not compromise eventual fairness and stability. Further, PCP is compatible with sharing links with legacy TCP hosts, making it feasible to deploy.
Iron Transport in Salmonella typhimurium LT-2: Prevention, by Ferrichrome, of Adsorption of Bacteriophages ES18 and ES18.hl to a Common Cell Envelope Receptor

Ferrichrome prevents adsorption of phages ES18 and ES18.h1 to cells of Salmonella typhimurium. Studies of albomycin-resistant mutants defective in both ferrichrome utilization and ES18.h1 adsorption suggest a sid gene may specify a receptor for both.
The Look of Success

In the wake of successful wolf reintroductions, managers who once fervently defended wolves are now faced with killing them. Are we ready for modern predator management?
Genetic deletion of the GATA1-regulated protein α-synuclein reduces oxidative stress and nitric oxide synthase levels in mature erythrocytes

α-Synuclein is highly expressed in neural tissue and during erythropoiesis, where the key erythroid regulator GATA1 has been found to modulate its expression. While specific α-synuclein (SNCA) mutations are known to cause autosomal dominant familial Parkinson's disease, its wild-type function remains under debate. To investigate the role of α-synuclein in murine hematopoiesis and erythropoiesis, we utilized Snca knock-out mice and analyzed erythroid compartments for maturation defects, in vivo erythrocyte survival, and erythrocyte-based reactive oxygen species (ROS) and nitric oxide synthase (NOS) levels. Our findings show that while bone marrow and spleen erythropoiesis and peripheral blood erythrocyte survival in Snca(-/-) mice was comparable to controls, the levels of ROS and of NOS-2 were significantly decreased in mature erythrocytes in these animals. These results indicate a role for α-synuclein in regulating oxidative stress in erythrocytes in vivo and could open new avenues for the investigation of its function in non-neural tissue.
Graph reduction for hierarchical control of energy integrated process networks

In this paper, we propose a graph-theoretic algorithm that can be used to analyze complex chemical processes comprising of multiple energy integration loops. Such networks are known to exhibit dynamics in multiple time scales. The algorithm uses information on the order of magnitude of the different energy flows and determines automatically the time scales where the units evolve, the manipulated inputs acting in the different time scales and the form of the reduced order models in each time scale. The application of the algorithm is illustrated through a case study of a benchmark chemical process.
The Pathway of HCV IRES-Mediated Translation Initiation

The HCV internal ribosome entry site (IRES) directly regulates the assembly of translation initiation complexes on viral mRNA by a sequential pathway that is distinct from canonical eukaryotic initiation. The HCV IRES can form a binary complex with an eIF-free 40S ribosomal subunit. Next, a 48S-like complex assembles at the AUG initiation codon upon association of eIF3 and ternary complex. 80S complex formation is rate limiting and follows the GTP-dependent association of the 60S subunit. Efficient assembly of the 48S-like and 80S complexes on the IRES mRNA is dependent upon maintenance of the highly conserved HCV IRES structure. This revised model of HCV IRES translation initiation provides a context to understand the function of different HCV IRES domains during translation initiation.
Epstein-barr Virus Infection and Multiple Sclerosis: A Review

Epstein-Barr virus (EBV) infection results in a life-long persistence of the virus in the host's B-lymphocytes and has been associated with numerous cancers including Burkitt's lymphoma, Hodgkin lymphoma, and nasopharyngeal carcinoma. There is considerable evidence that EBV infection is a strong risk factor for the development of multiple sclerosis. Early age at primary EBV infection is typically asymptomatic, but primary infection during adolescence or adulthood often manifests as infectious mononucleosis, which has been associated with a two- to threefold increased risk of MS. Most importantly, MS risk is extremely low in individuals who are EBV negative, but it increases several folds following EBV infection. Additional evidence supporting a role for EBV in MS pathogenesis includes the observations of elevated antibodies to EBV antigens (especially EBV nuclear antigen-1) prior to the onset of MS, and an increased risk of MS among EBV-positive children. The biological mechanism by which EBV may cause MS is not known, but several possibilities are discussed.
Evaluation of respiratory inductive plethysmography in the measurement of breathing pattern and PEEP-induced changes in lung volume.

Study Objective To assess the accuracy of the respiratory inductive plethysmography in the measurement of PEEP-induced changes in end-expiratory lung volume during mechanical ventilation and its accuracy and stability in the measurement of ventilation during controlled mechanical ventilation and spontaneous breathing. Design An open comparison between two methods using a criterion standard. Either a pneumotachometer (mechanically ventilated patients) or a spirometer (spontaneously breathing subjects) was used as the reference method. Setting Tertiary care center; a multidisciplinary intensive care unit and a metabolic research unit. Patients Six mechanically ventilated, paralyzed postoperative open heart surgery patients, six spontaneously breathing COPD patients, and eight healthy volunteers. Interventions Stepwise increases and reductions of PEEP from zero to 12 cm H 2 O during controlled mechanical ventilation; repeated validation of the calibration of the respiratory inductive plethysmography (RIP) in both mechanically ventilated and spontaneously breathing subjects. Measurements and Results The baseline drift of the RIP in vitro was 10 ml/150 min and in a ventilated model it was 20 ml/150 min. In mechanically ventilated patients, the mean error of the calibration after 150 min was within ± 5 percent. Change in end-expiratory lung volume (EELV) during the stepwise increase of PEEP up to 12 cm H 2 O was 849 ± 136 ml with the RIP and 809 ± 125 ml with the pneumotachometer (PT), and during the stepwise reduction of PEEP it was 845 ± 124 ml and 922 ± 122, respectively (not significant [NS]. The mean difference between methods in the measurement of change in EELV was −6.6 ± 3.5 percent during increasing and 6.6 ± 6.7 percent during decreasing PEEP (NS). Both in mechanically ventilated and spontaneously breathing subjects, the difference between methods was significant for VT and VT/TI. The difference in VT was −2.2 ± 0.2 percent during mechanical ventilation, −1.1 ± 0.5 percent in spontaneously breathing COPD patients, and 2.9 ± 0.4 percent in healthy volunteers (NS between groups). Conclusions The RIP is sufficiently accurate for the measurement of PEEP-induced changes in EELV during controlled mechanical ventilation. The accuracy of tidal volume measurement is similar during mechanical ventilation and spontaneous breathing. The calibration of the RIP is stable enough for bedside monitoring of changes in lung volumes. (Chest 1992; 102:234–38)
Pacing in children and young adults with nonsurgical atrioventricular block: Comparison of single-rate ventricular and dual-chamber modes

Abstract A prospective comparison of physiologic response to single-rate ventricular and dual-chamber atrioventricular pacing was conducted in 14 pediatric patients (age 1 to 24 years, median 14) with symptomatic nonsurgical second- or third-degree atrioventricular block. All patients were studied acutely during cardiac catheterization before and after 1 hour of both pacing modes. Following pacemaker implant, eight patients were reevaluated after 1 month of each mode with symptom questionnaire, resting ECG, resting echocardiogram, and Doppler cardiac output measurement at rest and at peak treadmill exercise. Cardiac outputs (mean ± standard error) increased acutely (n = 14) with both ventricular (32 ± 12%) and dual-chamber (39 ± 10%) pacing over intrinsic rhythm values ( p p 2 ) compared to single-rate ventricular pacing. Exercise-induced dysrhythmias occurred only with ventricular pacing. This study demonstrates that pediatric patients with nonsurgical atrioventricular block can compensate for loss of atrioventricular synchrony at rest but exhibit improved cardiac function with chronic dual-chamber atrioventricular compared to single-rate ventricular pacing.
Case studies of mathematics majors’ proof understanding, production, and appreciation

Abstract Proof understanding, production, and appreciation (PUPA) are important parts of a mathematician's repertoire. Many university students in the US, however, have difficulty with proof. One intent of this study was to examine the development of such students’ PUPAs and possibly to identify significant influences on that development, through interviews with the students throughout their studies in mathematics. Three case studies show a great variance in the development of the students’ proof skills. Some students come to university with excellent PUPAs and continue to thrive in a proof environment. Others enter university with poor PUPAs and unfortunately graduate without a significant change in their proof skills and attitudes. Still others come with poor proof skills but do show some growth during their undergraduate mathematics programs. Results of teaching experiments suggest that making proofs tangible is a means of helping those with poor PUPAs to grow in their proof understandings and abilities.
Nuestras antigüedades: la formación del canon poético medieval en el siglo XVIII

The article analyses the status of a small number of key texts of the Spanish Medieval literary canon prior to the constitution of Spanish Literature as an autonomous macrotextual formation inscribed in a fully nationalized culture. This analysis is concerned with shifts of meaning linked to changes both in the institutional setting in which texts are transmitted and in the network of interdiscursive relations within which these texts take on meaning.
Xylan O-acetylation impacts xylem development and enzymatic recalcitrance as indicated by the Arabidopsis mutant tbl29.

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Predicted forbidden line spectrum of NiIV

The spectrum of RR Telescopii in 1954 had a number of strong unidentified lines. To examine the possibility of some of these being due to Niiv we have calculated the energies of the 3d7 configuration of this ion. Estimates of the quantum-mechanical parameters have been made by extrapolation from known ions. Transition probabilities have been computed for magnetic dipole and electric quadrupole radiation for all possible transitions within the 3d7 configuration. Several predicted forbidden lines are in the region of unidentified lines in RR Telescopii; calculated energies are insufficiently accurate for definitive identifications to be made, but further laboratory work might lead to several identifications.
Sulfur geochemistry of hydrothermal waters in Yellowstone National Park, Wyoming, USA. II. Formation and decomposition of thiosulfate and polythionate in Cinder Pool

Abstract Cinder Pool is an acid-sulfate-chloride boiling spring in Norris Geyser Basin, Yellowstone National Park. The pool is unique in that its surface is partially covered with mm-size, black, hollow sulfur spherules, while a layer of molten sulfur resides at the bottom of the pool (18 m depth). The sulfur speciation in the pool was determined on four different days over a period of two years. Samples were taken to evaluate changes with depth and to evaluate the importance of the sulfur spherules on sulfur redox chemistry. All analyses were conducted on site using a combination of ion chromatography and colorimetric techniques. Dissolved sulfide (H 2 S), thiosulfate (S 2 O 3 2− ), polythionates (S x O 6 2− ), and sulfate were detected. The polythionate concentration was highly variable in time and space. The highest concentrations were found in surficial samples taken from among the sulfur spherules. With depth, the polythionate concentrations dropped off. The maximum observed polythionate concentration was 8 μM. Thiosulfate was rather uniformly distributed throughout the pool and concentrations ranged from 35 to 45 μM. Total dissolved sulfide concentrations varied with time, concentrations ranged from 16 to 48 μM. Sulfate was relatively constant, with concentrations ranging from 1150 to 1300 μM. The sulfur speciation of Cinder Pool is unique in that the thiosulfate and polythionate concentrations are significantly higher than for any other acid-sulfate spring yet sampled in Yellowstone National Park. Complementary laboratory experiments show that thiosulfate is the intermediate sulfoxyanion formed from sulfur hydrolysis under conditions similar to those found in Cinder Pool and that polythionates are formed via the oxidation of thiosulfate by dissolved oxygen. This last reaction is catalyzed by pyrite that occurs as a minor constituent in the sulfur spherules floating on the pool's surface. Polythionate decomposition proceeds via two pathways: (1) a reaction with H 2 S, yielding thiosulfate and elemental sulfur; and (2) by disproportionation to sulfate and thiosulfate. This study demonstrates that the presence of a subaqueous molten sulfur pool and sulfur spherules in Cinder Pool is of importance in controlling the pathways of aqueous sulfur redox reactions. Some of the insights gained at Cinder Pool may be relevant to acid crater lakes where sulfur spherules are observed and variations in polythionate concentrations are used to monitor and predict volcanic activity.
Sensory and Perceptual Interactions in Weight Perception

In four experiments, a multidimensional signal detection analysis was used to determine the influence of length, diameter, and mass on haptically perceived heaviness with and without vision. This analysis allowed us to test for sensory and perceptual interactions between mass and size. As in previous research, sensory interactions were apparent in all four experiments. A novel result was the appearance of perceptual interactions that became more prominent when diameter varied and when vision was allowed. Discussion focuses on how vision and the modalities of touch (i.e., haptic and dynamic) might influence which interactions appear in the data.
Comparison of signal and adaptive sensitivity profiles of the surround mechanism of cat retinal ganglion cells

Abstract Signal and adaptive sensitivity profiles of the surrounds of cat retinal ganglion cells were determined by varying the position of concentric annuli whose outside and inside diameters varied but whose total area remained constant. Signal sensitivity profiles were determined by adjusting the luminances of these annuli so as to produce a weak suprathreshold response of constant magnitude and time course. Adaptive sensitivity profiles were determined by varying the luminances of concentric equalarea, unmodulated annuli until the response to a temporally modulated annulus attained a criterion level. The results provided evidence that the retinal region over which the surround mechanism of an X cell pools adaptive information and pools signals are the same, and that the distribution of adaptive and signal sensitivities within these regions is similar. A small number of X cells showed local adaptation effects. The adaptive pooling area appeared to be smaller than the signal pooling area for Y cells.
Spectrophotometric variability in the Be star Gamma Cassiopeiae - Simultaneous ultraviolet and H-alpha observations

Simultaneous scans of the ultraviolet Si IV and Mg II resonance doublets in the spectrum of Gamma Cas with the Copernicus satellite during 64 continuous hours of observation, and H-alpha scans from a ground station, are described. No evidence is found for a rotation period of Gamma Cas, but narrow emission components in both ultraviolet doublets are reported along with a sudden emission increase on January 29.1, 1977 UT which appeared to be present in both H-alpha and the ultraviolet lines.
THE ORIGINS AND GOVERNANCE OF COMPLEX SOCIAL SYSTEMS

The new science of Complexity explains that limited knowledge prevents societies from predicting and controlling their developments. But Complexity further suggests that nature uses the limits of knowledge to evolve, which turns an apparent obstacle into an opportunity to reevaluate governmental institutions. As in nature, the limits of knowledge lead social systems to evolve by individuating, liberating, and empowering their members. Societies individuate and liberate their members to probe environments and exploit opportunities. Societies empower individuals to globalize their findings which requires constitutionally constraining governmental powers. Societies that respect human rights thus gain selective advantage. Showing that what nature is models what societies ought to be, Complexity may finesse the “naturalistic fallacy” of Hume and Moore.
Vibration Suppression of a Rotationally Periodic Structure Using an Adaptive-PPF Control Law

A jet turbine engine compressor disk is modeled as a rotationally periodic structure. An adaptive parameter estimator was used to eliminate the inter-blade coupling forces. The individual blade vibrations were then suppressed using a positive position feedback method. The resulting control law was tested on a simulated four and eight bladed system.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Surgical Considerations Following Preoperative Systemic Chemotherapy

The indications of neoadjuvant chemotherapy for breast cancer are extending to a larger population of breast cancer patients. The aims of this therapy are to transform the cancer to an operable form, downsize the tumor volume to allow a lumpectomy instead of a mastectomy, or to perform an in vivo test of the effect of the treatment on breast cancer in a specific individual. Along with these benefits, there is concern about the safety of lumpectomy and sentinel lymph node biopsy after neoadjuvant chemotherapy. In this review, we discuss the experience of breast conservation therapy after neoadjuvant chemotherapy and the reported recurrence rates in the preserved breasts. An overview of the studies that utilized sentinel lymph node biopsy after neoadjuvant chemotherapy is presented, summarizing the identification rates and false-negative rate.
Subcortical rotation in Xenopus eggs: An early step in embryonic axis specification☆

The amphibian egg undergoes a rotation of its subcortical cytoplasm relative to its surface during the first cell cycle. Nile blue spots applied to the egg periphery move with the subcortical cytoplasm and make rotation directly observable (J.-P. Vincent, G.F. Oster, and J. C. Gerhart (1986). Dev. Biol. 113, 484). We have previously shown that the direction of rotation accurately predicts the orientation of the embryonic axis developed by the egg. This suggests an important role for subcortical rotation in axis specification. In this report, we provide two kinds of experimental evidence for the essential role of rotation, and against a role for other concurrent cytoplasmic movements such as the convergence of subcortical cytoplasm toward the sperm entry point in the animal hemisphere. First, dispermic eggs develop only one embryonic axis, which is oriented accurately in line with the direction of the single rotation movement and not with the two convergence foci that form in the animal hemisphere. Rotation probably modifies the vegetal, not animal, hemisphere since axial development is normal in dispermic eggs despite highly altered animal subcortical movement. Second, we show that the amount of rotation correlates with the extent of dorsal development. UV irradiation of the vegetal hemisphere, or cold shock of the egg, inhibits rotation effectively. When there is no rotation, there is no dorsal development. On average within the egg population, increasing amounts of rotation correlate with the increasingly anterior limit of the dorsal structures of the embryonic body axis. However, individual partially inhibited eggs vary greatly in the amount of axis formed following a given amount of movement. Furthermore, the egg normally rotates more than is necessary for the development of a complete axis. These findings suggest that rotation, although essential, does not directly pattern the antero-posterior dimension of the body axis, but triggers a response system which varies from egg to egg in its sensitivity to rotation. This system is artificially sensitized by exposure of the egg to D2O shortly before rotation. We show that D2O-treated eggs produce extensive axes despite very limited rotation, often developing into hyperdorsal embryos. However, like normal eggs, they depend on rotation and cannot form dorsal structures if it is eliminated.
CDR substitutions of a humanized monoclonal antibody (CC49): contributions of individual CDRs to antigen binding and immunogenicity.

Abstract One of the major obstacles in the successful clinical application of monoclonal antibodies has been the development of host immune responses to murine Ig constant and variable regions. While the CDR grafting of MAbs may alleviate many of these problems, the potential remains that one or more murine CDRs on the human Ig backbone of a “humanized” MAb may still be immunogenic. Studies were undertaken employing a MAb of potential clinical utility, CC49, to define those CDRs that are essential for antigen binding and those that may be immunogenic in humans. We previously developed a humanized CC49 (HuCC49) by grafting the MAb CC49 hypervariable regions onto frameworks of human MAbs. To identify those CDRs essential for binding, a panel of variant HuCC49 MAbs was generated here by systematically replacing each of the murine CDRs with their human counterparts. The relative affinity constant of each variant was determined. Serum from a patient who received murine CC49 was used to determine the potential immunogenicity of each CDR in humans. The serum was shown to react with the anti-CC49 variable region. Results showed that patients’ anti-idiotypic responses are directed mainly against LCDR3 and moderately against LCDR1 and HCDR2. These studies demonstrate for the first time that variants containing individual CDR substitutions of a humanized MAb can be constructed, and each CDR can be defined for the two most important properties for potential clinical utility: antigen binding and immunogenicity.
Natural infection of an herbaceous host by Armillaria: a case study on Hemerocallis †

Abstract Symptoms of Armillaria root rot were observed on the herbaceous ornamental, Hemerocallis sp. (daylily), in a residential area in Walhalla, South Carolina, which was surrounded by dense, hardwood forest that also contained diseased hosts. Our objectives were to describe a natural occurrence of Armillaria root rot on daylily, a newly discovered host for the pathogen, and to characterize the Armillaria species involved. To characterize the Armillaria species collected from daylily, we used all available methods, including both traditional (sexual compatibility tests, basidiome morphology) and molecular (phylogenetic analyses of rDNA internal transcribed spacer, ITS, and intergenic spacer I, IGS-I) approaches. The presence of rhizomorphs in the topsoil of daylily beds and on the roots of symptomatic daylilies, coupled with our finding of identical ITS1 sequences among isolates originating from each of a rhizomorph, a daylily, and a neighbouring dogwood, suggests that Armillaria rhizomorphs had spread...
A Case of Sjögren's Syndrome With Repeatedly Negative Findings on Lip Biopsy

We report a case of Sjogren's syndrome characterized by keratoconjunctivitis sicca, parotid swelling, reduced salivary flow, and abnormalities on nuclear scanning. Two labial gland biopsies showed complete atrophy. Biopsy of an enlarged submandibular gland revealed lymphoid follicles and glandular replacement consistent with the diagnosis of Sjogren's syndrome. This case supports the concept that a negative finding on labial biopsy does not rule out a diagnosis of Sjogren's syndrome.
Segmentally distributed metamorphic changes in neural circuits controlling abdominal bending in the hawkmoth Manduca sexta

During the metamorphosis of Manduca sexta the larval nervous system is reorganized to allow the generation of behaviors that are specific to the pupal and adult stages. In some instances, metamorphic changes in neurons that persist from the larval stage are segment-specific and lead to expression of segment-specific behavior in later stages. At the larval-pupal transition, the larval abdominal bending behavior, which is distributed throughout the abdomen, changes to the pupal gin trap behavior which is restricted to three abdominal segments. This study suggests that the neural circuit that underlies larval bending undergoes segment specific modifications to produce the segmentally restricted gin trap behavior. We show, however, that non-gin trap segments go through a developmental change similar to that seen in gin trap segments. Pupal-specific motor patterns are produced by stimulation of sensory neurons in abdominal segments that do not have gin traps and cannot produce the gin trap behavior. In particular, sensory stimulation in non-gin trap pupal segments evokes a motor response that is faster than the larval response and that displays the triphasic contralateral-ipsilateral-contralateral activity pattern that is typical of the pupal gin trap behavior. Despite the alteration of reflex activity in all segments, developmental changes in sensory neuron morphology are restricted to those segments that form gin traps. In non-gin trap segments, persistent sensory neurons do not expand their terminal arbors, as do sensory neurons in gin trap segments, yet are capable of eliciting gin trap-like motor responses.
When is a heavy quark not a parton? Charged Higgs production and heavy quark mass effects in the QCD-based parton model

Abstract Several issues pertaining to the application of the QCD-based parton model to new physics processes involving heavy partons are described and quantitatively studied using charged Higgs boson production as a prime example. The naive parton model predictions are found to over-estimate the actual cross section by a factor of 2 to 5, depending on the top-quark and Higgs masses. The role of the top quark as a “parton” is examined by a detailed study of the cancellation between the straight parton model contribution and a subtraction term required by QCD corrections. The accuracy of the zero-mass method for evaluating the first-order QCD correction is assessed (in light of the potentially large mass of the top quark) by a quantitative analysis of the cancellation of mass singularities between the correction terms. A pragmatic procedure for calculation based on a renormalization scheme without the heavy quark-parton is formulated and compared with the usual perturbative QCD formalism. The energy ranges over which heavy quarks (or other particles) should or should not be naturally treated as “partons” are delineated. Properly evolved parton distribution functions relevant to the specific renormalization schemes considered are employed for all the numerical studies in order to ensure consistency in the QCD framework.
Initial Complexes of Prime Ideals

Abstract The simplicial complex defined by any initial ideal of a prime ideal is pure and strongly connected. This proves a conjecture of Kredel and Weispfenning [12, p. 234].
Pharmacological selectivity of the cloned human P2U-purinoceptor: potent activation by diadenosine tetraphosphate.

Abstract 1. The human P2U-purinoceptor was stably expressed in 1321N1 human astrocytoma cells and the pharmacological selectivity of the expressed receptor was studied by measurement of inositol lipid hydrolysis. 2. High basal levels of inositol phosphates occurred in P2U-purinoceptor-expressing cells. This phenomenon was shown to be due to release of large amounts of ATP from 1321N1 cells, and could be circumvented by adoption of an assay protocol that did not involve medium changes. 3. UTP, ATP and ATP gamma S were full and potent agonists for activation of phospholipase C with EC50 values of 140 nM, 230 nM, and 1.72 microM, respectively. 5BrUTP, 2C1ATP and 8BrATP were also full agonists although less potent than their natural congeners. Little or no effect was observed with the selective P2Y-, P2X-, and P2T-purinoceptor agonists, 2MeSATP, alpha,beta-MeATP, and 2MeSADP, respectively. 4. Diadenosine tetraphosphate, Ap4A, was a surprisingly potent agonist at the expressed P2U-purinoceptor with an EC50 (720 nM) in the range of the most potent P2U-purinoceptor agonists. Ap4A may be a physiologically important activator of P2U-purinoceptors.
Realistic expectations of surgical treatment of aortic dissections: the Stanford experience.

Over a 16-year span, 125 unselected patients with acute and chronic aortic dissections underwent uniform surgical treatment. Fifty-three had acute type A(Ac-A), 29 had chronic type A(Ch-A), 20 had acute type B(Ac-B), and 23 had chronic type B(Ch-B) dissections. Major preoperative complications were encountered frequently; 14% of dissections had ruptured. All patients underwent aortic replacement with tubular grafts; concomitant aortic valve replacement (AVR) was performed in 11% of the Ac-A patients and 38% of Ch-A patients. The primary intimal tear was resected in 78% of operations. Follow-up averaged 4.5 years and extended beyond 13 years. Overall operative mortality rate was 34% for Ac-A, 14% for Ch-A, 45% for Ac-B, and 22% for Ch-B patients. Between January, 1974 and October, 1979 these mortality rates (63 patients Ac-A, 17 Ch-A, 7 Ac-B, 12 Ch-B) declined to 22%, 18%, 14%, and 17%, respectively. Actuarial survival rates (± SEM) for the entire series were 54±5% at 5 years and 26±7% at 10 years. Excluding operative deaths, these were 76±5% and 37±10% at similar intervals. Multiple preoperative variables correlated with both operative risk and long-term survival, but the survival rate appeared not to be influenced by whether AVR was performed (type A patients) or by whether the primary intimal tear was resected (all patients). No differences in long-term survival were evident between the 4 subgroups of patients. Survivors generally sustained satisfactory functional results and experienced good rehabilitation.
Phosphorescence imaging system using an acousto-optic tunable filter and a charge-coupled device

Abstract We are reporting for the first time the development of an imaging spectrometer for solid-surface room temperature phosphorimetry based on an acousto-optic tunable filter. A HeCd laser was employed as the excitation source, and a cooled two-dimensional charge-coupled device was used as the detector. The spectral characterization and imaging capability of the new system were evaluated with two well known phosphorescent compounds. Thee phosphorescence emissions of pyrene and 1,2,3,4-dibenzanthracene adsorbed on chromatography paper treated for background reduction were investigated. Thallium(I) acetate was employed as a phosphorescence enhancer. Based on the performance of the proposed instrument, several potential applications are discussed.
Electrical conductance of parallel atomic wires

The effects of lateral interactions on the conductance of two atomic wires connected in parallel are investigated using density-functional theory. Carbon-atom wires with a cumulene structure end bonded to two metal electrodes are used as the model system. Large variations of the low-bias conductance of the system as a function of the separation of the two wires on the atomic scale are predicted. This variation results from two types of interactions: (a) a direct bonding interaction between the atomic wires, and (b) an indirect interaction associated with the presence of the metal electrodes. The electrodes transfer an amount of charge to the carbon wires that varies with the separation d between the wires by as much as a factor of 2. The conductance changes, as a function of d, follow closely the variation of the density-of-states of the system at the Fermi level.
Pre-steady-state kinetic studies on the Glu171Gln active site mutant of adenosylcobalamin-dependent glutamate mutase.

Glutamate-171 is involved in recognizing the amino group of the substrate in glutamate mutase. The effect of mutating this residue to glutamine on the ability of the enzyme to catalyze the homolysis of adenosylcobalamin has been investigated using UV−visible stopped-flow spectroscopy. Although Glu171 does not contact the coenzyme, the mutation results in the apparent rate constants for substrate-induced homolysis of the coenzyme that are slower by 7-fold and 13-fold with glutamate and methylaspartate, respectively, than those measured for the wild-type enzyme; furthermore, it weakens the binding of these substrates by ∼50-fold and ∼400-fold, respectively. These observations lend support to the idea that the enzyme may use substrate binding energy to accelerate homolysis of the coenzyme. The mutation also results in isotope effects on coenzyme homolysis that are much smaller than the very large effects observed when the wild-type enzyme is reacted with deuterated substrates. This observation is consistent ...
A rapid method for the determination of glycosylated hemoglobins using high pressure liquid chromatography

Abstract Hemoglobin (Hb) AIc is a minor component of Hb found in normal individuals but elevated two or threefold in patients with diabetes mellitus. Limited studies have suggested that the level of Hb AIc is proportional to the integrated concentration of glucose over time. Thus it could serve as an index of hyperglycemia. Its measurement may enable a more objective approach to assessing whether or not the control of hyperglycemia can be correlated with the severity of complications of diabetes. Large scale clinical studies of Hb AIc have not been undertaken for lack of a rapid assay system. This article describes a method of high pressure liquid chromatography (HPLC) which enables the isolation of Hb AIc in 27 min using only 12 μg of Hb (100 μl of blood) and a second method for the isolation of total fast Hb components (also elevated in diabetes) in 11 min. Using the first method, a total of 36 assays were performed on the blood of a single normal volunteer over a one month period. The mean level of Hb AIc was 4.95 ± 0.12% (SD) ± 0.02% (SEM), while the coefficient of variation (C.V.) was 2.4%. The mean Hb AIab p
Risk of thromboembolism with the aortic Carpentier-Edwards bioprosthesis

Porcine bioprostheses provide an excellent alternative to mechanical prostheses for heart valve replacement in patients unable to comply with systemic anticoagulation and in the elderly. Long-term results of this prosthesis, however, demonstrated identical survival and parallel event-free status, albeit at a lower rate than the mechanical valves. Some discrepancy exists as to the need for and duration of systemic anticoagulation in the bioprosthesis, and some evidence exists to contraindicate anticoagulation due to a higher late mortality rate in patients with an aortic bioprosthesis. The records of 561 patients having the Carpentier-Edwards bioprosthesis in the aortic position as an isolated valve procedure were reviewed. The overall rate of bioprosthetic failure events was low (0.23%/patient year) and the survival (5 year, 74.8 ± 2.4%; 10 year, 52.9 ± 4.9%) and event-free statistics (5 year, 67.9 ± 2.6%; 10 year, 42.4 ± 5.1%) were excellent. No gender difference was present. A vulnerable period for neurologic events was identified by hazard function whereby the incidence of stroke was high; these were increased in the patient variables of compromised ejection fraction (0.54; p ≤ 0.003), older age (≤73 years; p ≤ 0.02), and preoperative atrial fibrillation or paced rhythm ( p ≤ 0.01). This pattern was similar for both transient ischemic events and strokes and rapidly decreased over the first few months of the first year and the first few years of the 12-year follow-up. These patients were not routinely anticoagulated. Although, in general, patients receiving a bioprosthesis in the aortic position do not require anticoagulants, a subset of patients have been identified who should receive short-term anticoagulation in an attempt to reduce the high early incidence of neurologic events.
Calcium Depletion Modifies the Structure of the Photosystem II O2-Evolving Complex†

A 5 min exposure of photosystem II to a pH 3 citric acid solution is a simple method for selective removal of Ca2+ from the O2-evolving complex. The resulting preparation retains the 23 and 17 kDa extrinsic polypeptides, but the activity of this material is only 10−20% of that of an untreated control sample. Biochemical characterization of citrate-treated photosystem II reveals that some reaction centers lose the extrinsic proteins during citrate treatment. Furthermore, a comparison of photosystem II preparations treated with citrate, or depleted of 23 and 17 kDa extrinsic polypeptides by high-salt treatment, shows that low concentrations of a small reductant, NH2OH, which has little effect on the activity of intact photosystem II, can reduce and inhibit the Mn cluster in both types of preparations. In contrast, a large reductant, hydroquinone, cannot access the majority of O2-evolving centers in citrate-treated preparations, while 23 and 17 kDa-depleted material is rapidly inactivated by the reductant. I...
Exercise Involvement and Eating-Disordered Characteristics in College Students

Abstract While several reports have suggested a relationship between involvement in regular exercise activity and the presence of eating disorders or eating-disordered characteristics, other research has demonstrated no such association. Methodological difficulties and interpretive differences among researchers contributing to these disparate findings are reviewed. The present study investigated the relationship between exercise involvement and eating-disordered characteristics in 159 “exerciser” and 129 “nonexer-ciser” male and female undergraduates. Women who were involved in regular exercise demonstrated more bulimic/anorectic eating attitudes and a greater drive for thinness than the women who were not involved in regular exercise. Further, results suggest that women involved in regular exercise who show disordered eating concerns do not manifest the personality characteristics associated with eating disorders that are shown among female nonexercisers with similar levels of disordered eating concerns....
On measuring the shadow price of uncommitted fiscal resources in Africa

Abstract Underevaluation of the opportunity cost of uncommitted fiscal resources in African countries results in approval of development projects which later collapse when local budget support for operation and maintenance is not forthcoming. A Cobb-Douglas production function is presented, using as factors (A) the civil service establishment and (B) real government expenditure on complementary goods and services. Assuming tangency in the early 1970s before civil service expansion notwithstanding fiscal stringency led to compression of (B), plausible parameters yield a current marginal product of (B) that is twice or more the tangency value, implying a shadow price of 2.0+ for uncommitted fiscal resources.
Extended Hough transform for linear feature detection

Improving the accuracy of line segment detection reduces the complexity of subsequent high-level processing common in cartographic feature detection. We developed a new extension to the Hough transform and reported on its application to building extraction. We expanded the Hough space by a third parameter, the horizontal or vertical coordinate of the image space, to provide incremental information as to the length of the lineal feature being sought. Using this extended HT transform allowed us to more accurately detect the true length of a line segment. In addition, we used a Bayesian probabilistic approach to process our extended Hough space that further increased the accuracy of our extended Hough transform.
Evaluation of amiodarone therapy in the treatment of drug-resistant cardiac arrhythmias: Long-term follow-up

The clinical efficacy of amiodarone in the management of complex cardiac arrhythmias refractory to therapy with two or more conventional or other investigational antiarrhythmic agents was determined by long-term follow-up in patients who had received the drug for at least 3 months. A total of 181 patients, classified into four groups (group 1, supraventricular arrhythmias, n = 42; group 2, frequent ventricular premature complexes, n = 46; group 3, nonsustained ventricular tachycardia, n = 16; and group 4, sustained ventricular tachycardia, n = 77) received a daily maintenance dose of 200 to 800 mg amiodarone for up to 30 months. There was a total of 26 deaths (14%). Ten of these were probably attributable to arrhythmia, although all patients had either good or excellent response to therapy over a mean follow-up of 14.9 months prior to death. The drug had to be permanently discontinued because of side effects in only three patients, and in the majority of patients with side effects, symptoms could be alleviated with adjustment of dosage, thyroid replacement therapy, or temporary cessation of therapy. We conclude that amiodarone is highly effective in high-risk patients with complex refractory cardiac arrhythmias, and that close monitoring and prompt recognition of side effects and appropriate adjustment of dosage or institution of supplemental or replacement therapy (in less than 5% of patients) will allow continuation of amiodarone. The benefit of suppression of symptomatic arrhythmias and the potential of prevention of sudden death clearly outweigh the modest incidence of severe side effects.
Indicators of What for What

Research has a variety of motives including intellectual curiosity, advancing one's career, and obtaining ongoing funding. However, anyone who chooses an environmental science as a career also has ...
Effects of ground corn particle size on ethanol yield and thin stillage soluble solids

ABSTRACT The effects of ground corn particle size on ethanol yield and soluble solids in thin stillage was evaluated using a 2-L laboratory dry-grind procedure. The procedure was optimized for grinding, liquefaction, sacchari-fication, and fermentation parameters. The optimized procedure was reproducible with a coefficient of variation of 3.6% in ethanol yield. Five particle size distributions of ground corn were obtained using a cross-beater mill equipped with five screens (0.5, 2, 3, 4, and 5 mm). Particle size had an effect on ethanol yield and on soluble solids concentration in thin stillage. The highest ethanol yield of 12.6 mL/100 mL of beer was achieved using a 0.5-mm screen in the cross-beater mill. Treatment using the 0.5-mm mill screen resulted in soluble solids concentration of 25.1 g/L and was higher than soluble solids concentrations obtained with other screens. No differences in soluble solid concentrations were observed in samples of thin stillage obtained from 2, 3, 4, and 5-mm screens whi...
A Note on Derivatives of p‐Thymotic Alcohol

Abstract p ‐Thymotic alcohol is related structurally to thymol and benzyl alcohol, both of which are accepted therapeutic agents. The preparation of the alcohol and certain of its characterizing derivatives seemed practical in that the compound has theoretical potential as a medicinal substance. The preparation and properties of the alcohol are described and derivatives of it were analyzed and identified.
Leaf adaptations of some Shorea species to sun and shade

summary Seedlings of four species of the genus Shorea section Doona were examined. All co-exist in the moist evergreen rain forest of southwestern Sri Lanka. Experiments were designed to investigate some physiological and anatomical attributes of leaves under different light conditions. The attributes considered were net photosynthesis, transpiration, stomatal conductivity, blade and cuticle thickness, stomatal frequency, thickness of upper epidermis and palisade mesophyll, and number of palisade layers. Results demonstrate the close association between anatomical adaptation and efficiency in physiological processes. Results also elucidate some of the relationships between distribution patterns of species across the forest topography and their differences in light and drought tolerance. This indicates that an important period determining site specialization of a species occurs during regeneration establishment. These relationships are not as simple or as ecologically noticeable though as for those relationships documented in many previous studies between tree species of markedly different successional stages or taxonomy.
New measures of the output gap based on the forward-looking new Keynesian Phillips curve ☆

Abstract Forward-looking versions of the New Keynesian Phillips curve imply that the output gap, the deviation of the actual output from its natural level due to nominal rigidities, drives the dynamics of inflation relative to expected inflation. We exploit this to set up a bivariate unobserved component model for extracting new estimates of the output gap in the US. The gap estimates are large and persistent even after allowing for correlated trend and cycle shock. We then augment our model to use the information in the unemployment rate. The estimates confirm the presence of a large and persistent cyclical component.
β-Secretases, Alzheimer’s Disease, and Down Syndrome

Individuals with Down Syndrome (DS), or trisomy 21, develop Alzheimer's disease (AD) pathology by approximately 40 years of age. Chromosome 21 harbors several genes implicated in AD, including the amyloid precursor protein and one homologue of the β-site APP cleaving enzyme, BACE2. Processing of the amyloid precursor protein by β-secretase (BACE) is the rate-limiting step in the production of the pathogenic Aβ peptide. Increased amounts of APP in the DS brain result in increased amounts of Aβ and extracellular plaque formation beginning early in life. BACE dysregulation potentially represents an overlapping biological mechanism with sporadic AD and a common therapeutic target. As the lifespan for those with DS continues to increase, age-related concerns such as obesity, depression, and AD are of growing concern. The ability to prevent or delay the progression of neurodegenerative diseases will promote healthy aging and improve quality of life for those with DS.
Evaluating the sample likelihood of linearized DSGE models without the use of the Kalman filter

Abstract This paper derives a method for constructing the likelihood function of a general class of linearized dynamic general equilibrium models that does not require the application of the Kalman filter. The method easily handles models in which variables are observed with error.