cssi/SciSciGPT-SciSciNet huggingface dataset:
Pseudofossils: A Plea for Caution

The geologic account of ancient life is plagued with reports that do not withstand critical assessment. This is a special problem in the older rocks, where reports of spurious records continue to dilute the authentic record of evolution on the primitive Earth. The problem is illustrated by brief analyses of three timely examples of widely different ages. These are (1) desiccation curls interpreted as arthropods, (2) drag marks resembling “worm tracks,” and (3) pyrite rosettes interpreted as medusae. It is left to the reader to draw conclusions about similar instances not here alluded to; the record of alleged pre-Phanerozoic life is full of them.
An elastic model of the large-scale structure of duplex DNA.

A general model for the large-scale, time-independent structure of duplex DNA is developed based on elastic considerations. The general conditions of elastic equilibrium are given. These equations are solved for the equilibrium shape of stressed duplex DNA, based on the assumption that the double helix behaves mechanically as a symmetric, linearly elastic rod. It is shown that, in general, two orders of superhelicity will arise at equilibrium. Several possible applications of this approach to the supercoiling of closed circular DNA are described.
Fallow Effects on Soil Carbon and Greenhouse Gas Flux in Central North Dakota

The inclusion of cover crops during fallow (i.e., green fallow) may mitigate greenhouse gas (GHG) emissions from dryland cropping systems. An investigation was conducted to quantify the effects of chemical and green fallow on soil organic C (SOC) and CO 2 , CH 4 , and N 2 O flux within springwheat (Triticum aestivum L.)-fallow (chemical fallow) and spring wheat-safflower (Carthamus tinctorius L.)-rye (Secale cereale L.) (green fallow) under no-till management in west-central North Dakota. Using static chamber methodology, flux measurements were made during 19 mo of the fallow period of each cropping system. Soil samples collected before initiation of flux measurements indicated no difference in SOC in the surface 10 cm between cropping systems. Additionally, differences in gas flux between cropping systems were few. Emission of CO 2 was greater under green fallow than chemical fallow during spring thaw until the termination of rye (P = 0.0071). Uptake of atmospheric CH 4 was the dominant exchange process during the evaluation period, and was significantly (P = 0.0124) greater under chemical fallow (-2.7 gCH 4 -C ha -1 d -1 ) than green fallow (-1.5 g CH 4 -C ha -1 d -1 ) following the termination of rye. Cumulative fluxes of CO 2 , CH 4 , and N 2 O did not differ between the chemical- and green-fallow phases during the 19-mo period (P = 0.1293, 0.2629, and 0.9979, respectively). The results from this evaluation suggest there was no net GHG benefit from incorporating a rye cover crop during the fallow phase of a dryland cropping system under no-till management.
XPS analysis of Mount St. Helens ash

Abstract An analysis of ash collected following the eruption of Mount St. Helens is detailed. Seven samples collected from six locations in Washington were analyzed by scanning electron microscopy/energy dispersive analysis of x-rays (SEM/EDAX) and X-ray photoelectron spectroscopy (XPS). Data reported in the literature demonstrates that the ash with particle size 2 S and SO 2 were measured in the atmosphere following eruption.
The Investigation of the Enhancement Mechanisms of the Oxide Treatment on Cemented Carbide Tools

The mechanisms responsible for enhancement of the metal cutting properties of cemented carbide tools during oxide treatments are investigated. The reaction of individual phases present in cemented carbide tools with various oxides was analyzed experimentally under temperature-pressure conditions previously employed for the oxide treatment. The change in the surface structure and the formation of new phases were determined by means of X-ray diffraction, oxidation experiments, and thermodynamic analyses. The experimental results show that during the oxide treatment such carbides as TiC and ZrC, which are chemically more stable than WC, form on the surface of WC. It was also found that a small percentage of oxides mixed in the eutectic phase of Co-WC stabilizes the eutectic phase, thus preventing its adhesion to a solid piece of oxides.
Photochemical hole-burning in photosynthetic reaction centers

Abstract The change in absorbance (hole spectrum) of the primary electron donor (P870) in bacterial photosynthetic reaction centers has been studied at 1.5–2.1 K following narrow-band excitation at several wavelengths within the P870 absorption band. The hole width is very large, suggesting a homogeneous linewidth on the order of 200–300 cm−1. Possible interpretations of this highly unusual result, including ultra-fast excited-state decay, are discussed.
Antimicrobial Treatment and Clinical Outcomes of Carbapenem-Resistant Acinetobacter baumannii Ventilator-Associated Pneumonia:

Objectives: Carbapenem-resistant (CR) Acinetobacter baumannii is an important pathogen in ventilator-associated pneumonia (VAP), but therapeutic options are limited. We describe the clinical outcomes of the largest case series of CR-Acinetobacter VAP reported to date. Methods: A retrospective analysis of 55 participants with CR-Acinetobacter VAP from July 2004 to December 2007 was undertaken. The primary endpoint was clinical response or microbiological eradication. Secondary endpoint was treatment-associated nephrotoxicity defined as ≥50% increase in serum creatinine or an increase of ≥0.5 mg/dL during therapy. Results: Forty-two (76.4%) participants achieved clinical response at the completion of therapy. Clinical responses were achieved in 60.0% of sulbactam-based, 66.7% of polymyxin-based, 77.8% of aminoglycoside-based, 80.6% of minocycline-based, and 90.0% of tigecycline-based regimens. Follow-up sputum cultures were available in 6 of 10 tigecycline-treated participants with 4 of 6 isolates developin...
Quartz ceramic nozzles for casting steel on continuous casting plant

A technology was developed for making steel casting nozzles for the continuous casting of steel with different versions of lateral input of metal into the crystallizer. In laboratory conditions we made nozzles 600–650 mm long.
The magnitude of fetal renal pelvic dilatation can identify obstructive postnatal hydronephrosis, and direct postnatal evaluation and management.

Purpose: Up to 1% of prenatal ultrasounds will detect fetal renal pelvic dilatation. We sought to evaluate and determine whether fetal renal pelvic measurements may appropriately direct prenatal counseling and postnatal evaluation and management.Materials and Methods: We performed a retrospective analysis of prospectively collected measurements of anteroposterior renal pelvic dilatation obtained at a single fetal maternal medicine center between 1990 and 2003. Fetuses with renal pelvic dilatation 4 mm or greater at less than 33 weeks of gestation, or 7 mm or greater at more than 33 weeks of gestation were evaluated postnatally at a single pediatric urology center. Infants with renal pelvic dilatation were evaluated with ultrasound, voiding cystourethrograms and renal scintigraphy. Renal obstruction was the main outcome measure assessed. Obstruction was defined as the need for surgery and was not based on the renal scan drainage time. Indications for surgery included declining function and increasing hydro...
Immunohistochemical expression of C-myc oncogene, heat shock protein 70 and HLA-DR molecules in malignant cutaneous melanoma.

The clinical course of malignant melanomas is frequently unpredictable, although a number of prognostically useful variables can be identified. There is a need for additional markers of prognostic value. In a series of 60 malignant cutaneous melanomas, we analysed the immunohistochemical expression of c-myc proto-oncogene, heat shock protein 70 (HSP70) and HLA-DR molecules in order to investigate their prognostic significance. C-myc, HSP70 and HLA-DR were expressed in 43.3%, 56.6% and 38.3% of all melanoma cases, respectively. Advanced Clark levels (Clark III–V) were significantly associated with c-myc expression rate (P 1.5 mm) was related to HLA-DR expression (P<0.05). High mitotic rate was closely associated with c-myc positivity (P<0.05), while HSP70 and HLA-DR expression separately correlated to clinical stage of the disease (P<0.05). The evaluation of these variables may be of immunological and prognostic significance. They were found to be associated with melanocyte subpopulations of the vertical growth phase which are arguably characterized by an increased invasive potential.
Titrating matching-to-sample performance in pigeons: effects of diazepam, morphine, and cholinergic agents.

Abstract Five adult, male White Carneau pigeons were trained to respond under a titrating matching-to-sample schedule of reinforcement. Under this titration schedule, each trial began with the presentation of a sample stimulus (red or green light) on the center key of a three-key pigeon chamber. Completion of 15 responses on the center key resulted in the termination of the stimulus presentation and the initiation of a delay period. The length of the delay changed as a function of the pigeon's performance. During the first five trials of each session, the delay was fixed at 3 s in length. On the sixth and all subsequent trials, the length of the delay was either increased, did not change, or decreased such that accuracy was maintained at approximately 80%. Following the delay, two of the three pigeon keys were transilluminated with different colored lights (red or green). A single response upon the key transilluminated with the same stimulus color as the sample stimulus resulted in the presentation of food. A response on the key transilluminated with the stimulus color that did not match the sample stimulus resulted in a time-out period. Using this procedure, the effects of two drugs of abuse, diazepam (0.03–3 mg/kg) and morphine (0.03–10 mg/kg), a muscarinic antagonist, scopolamine (0.003–0.3 mg/kg), the quaternary derivative of scopolamine, methylscopolamine (0.003–0.3 mg/kg), a cholinesterase inhibitor, physostigmine (0.003–0.1 mg/kg), and the quaternary derivative of physostigmine, neostigmine (0.003–0.1 mg/kg), were determined. Diazepam decreased matching accuracy such that a decrease in the mean delay value for the session was observed. The decreases in the mean delay value were observed at doses that did not decrease rate of responding or increase the latency to initiate a trial. Morphine did not affect the mean delay value despite marked effects on response latency. Scopolamine, like diazepam, decreased the mean delay value but only at doses that also decreased rate of responding and increased the latency to initiate a trial. Methylscopolamine only produced effects on the mean delay and response rate at the highest dose tested (0.3 mg/kg), suggesting that the effects observed with scopolamine were centrally mediated. The only effect observed with physostigmine was a decrease in the mean delay value at the highest dose studied (0.1 mg/kg), a dose that also increased the latency to initiate a trial. When neostigmine was studied, the 0.1 mg/kg dose decreased the mean delay value and increased response latency, suggesting that the effects of physostigmine at this dose may be mediated peripherally. These results show that both diazepam and scopolamine disrupt matching accuracy. The results also suggest a greater specificity in the effect of diazepam compared to scopolamine because the separation between doses that disrupt matching accuracy and doses that suppress rate of responding is greater for diazepam than for scopolamine.
Applying the dominance hierarchy model to pride and shame, and related behaviors

Abstract This paper offers a functional, comparative view of a relatively neglected emotion: pride and shame. Parallels between the nonverbal expression of pride and shame in humans, on the one hand, and of dominance and submission in other species on the other, have long been noted. However, many other parallels exist between competitive behavior in humans (prompted by the affect of pride and shame) and dominance behavior in other primates. These additional parallels strengthen the claim that human competitive behavior evolved from primate dominance behavior. This expanded dominance model of human competitive behavior also might allow various aspects of our social behavior to be understood functionally and comparatively. That is, a fuller application of the dominance model of human competitive behavior, which is motivated by pride and shame, might elucidate many facts about human social behavior that otherwise remain theoretically unmoored. Possible future directions for research into this emotion comple...
Primary mirror shape control for athermalization using embedded sensors

The next generation of space telescopes will be required to meet very challenging science goals. In order to achieve these goals, the size of the primary mirror will need to be increased. However, since current telescopes are reaching their limits in terms of size and mass, new designs will require advanced technologies such as lightweight mirrors and active optical control. Traditional shape control of the primary mirror relies on feedback from a wavefront sensor located in the optical path. However, a wavefront sensor reduces the amount of light available for image formation. Therefore, to view very dim objects, it will be necessary to use a different type of sensor. In this work, a quasi-static shape control algorithm is developed to correct errors in the mirror due to thermal disturbances using only sensors embedded in the mirror. Control algorithms are presented for both embedded strain gages and temperature sensors. Finite element models of both a simple flat plate mirror and a rib-stiffened mirror are generated and analyzed using Nastran. The flat plate model, with surface-parallel actuation is used to compare the two algorithms. Following this, the parametric model for a rib-stiffened mirror is used to analyze the effects of the shape control algorithm as the mirror geometry is changed. It is shown that correction of a mirror can be achieved using these embedded sensors.
Tissue probability map constrained 4D clustering algorithm for increased accuracy and robustness in SerialMR brain image segmentation

The traditional fuzzy clustering algorithm and its extensions have been successfully applied in medical image segmentation. However, because of the variability of tissues and anatomical structures, the clustering results might be biased by the tissue population and intensity differences. For example, clustering-based algorithms tend to over-segment white matter tissues of MR brain images. To solve this problem, we introduce a tissue probability map constrained clustering algorithm and apply it to serial MR brain image segmentation, i.e., a series of 3-D MR brain images of the same subject at different time points. Using the new serial image segmentation algorithm in the framework of the CLASSIC framework, which iteratively segments the images and estimates the longitudinal deformations, we improved both accuracy and robustness for serial image computing, and at the mean time produced longitudinally consistent segmentation and stable measures. In the algorithm, the tissue probability maps consist of both the population-based and subject-specific segmentation priors. Experimental study using both simulated longitudinal MR brain data and the Alzheimer's Disease Neuroimaging Initiative (ADNI) data confirmed that using both priors more accurate and robust segmentation results can be obtained. The proposed algorithm can be applied in longitudinal follow up studies of MR brain imaging with subtle morphological changes for neurological disorders.
Characterization of secretion of thymosin alpha 1 and thymosin beta 4 during prepuberty, estrus and pregnancy in the bovine female.

The objective of the present study was to characterize secretion of thymosin alpha 1 (A1) and thymosin beta 4 (B4) during different stages of ovarian function and pregnancy in bovine females. One hundred and thirty-five prepubertal heifers averaging 9 mo of age at the time the study was initiated were used. Estrous detection was conducted twice daily using intact bulls fitted with marking harnesses. Blood samples were collected at first behavioral estrus and at the time of rectal palpation for pregnancy. Heifers were weighed at the beginning of the study and every 56 days and additional blood samples were collected at those times. Plasma was harvested and radioimmunoassays were conducted to quantify concentrations of thymosin A1 and B4. Mean concentrations of thymosin A1 and thymosin B4 were determined during prepuberty, estrus during which conception did not occur, estrus during which conception did occur, pregnancy and in heifers that failed to attain puberty. Mean plasma concentrations of thymosin A1 and B4 were greater at estrus during which conception occurred than at any other period (P less than .01). Regressions of days prepubertal and days post conception on thymosin A1 and B4 were analyzed. During the 100 days prior to puberty, thymosin A1 and B4 did not change in the heifers that ultimately conceived. However, in the heifers that were never determined to be pregnant by rectal palpation, concentrations of both thymosin A1 and B4 increased linearly during prepuberty (P less than .01). A decline in thymosin A1 and B4 concentrations occurred in a quadratic fashion from conception through the first 100 d of pregnancy (P less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)
Mechanistic modelling of tests of unbound granular materials

Various tests are used to characterise the strength and resilience of granular materials used in the subbase of a pavement system, but there is a limited understanding of how particle properties relate to the bulk material response under various test conditions. Here, we use discrete element method (DEM) simulations with a mechanistically based contact model to explore influences of the material properties of the particle on the results of two such tests: the dynamic cone penetrometer (DCP) and the resilient modulus tests. We find that the measured resilient modulus increases linearly with the particle elastic modulus, whereas the DCP test results are relatively insensitive to particle elastic modulus. The DCP test results are also relatively insensitive to inter-particle friction coefficient but strongly dependent on the particle shape. We discuss strengths and weaknesses of our modelling approach and include suggestions for future improvements.
Descending Projections to Spinal Motor and Sesory Cell Groups in the Monkey: Cortex versus Subcortex

In rhesus monkeys, corticospinal fibers have been found to terminate in motor, sensory, and internuncial cell groups. The present study reveals that the subcorticospinal fibers terminate primarily on internuncial neurons. Possible mechanisms involved in transmission of cortical and subcortical influences on motor and sensory cell groups are discussed.
Contrast-enhanced MRI for quantification of myocardial viability.

During the past 10 years substantial advances have taken place in magnetic resonance imaging (MRI) capabilities and in contrast media development. Furthermore, knowledge of in vivo contrast media interactions with surrounding water and distribution into tissue has increased, permitting regional quantification of concentration-time profiles in the myocardium. The combination of these advances has substantially improved the capability of contrast-enhanced MRI characterization of myocardial ischemic injury, including its ability to discriminate viable from nonviable zones. Discrimination of viable from nonviable myocardial subregions is important for patient management and for research applications. This review addresses recent progress toward the goal of defining viable and nonviable myocardium based on MRI detection of contrast media effects. J. Magn. Reson. Imaging 1999;10:694–702. © 1999 Wiley-Liss, Inc.
Acetazolamide teratogenesis in Wistar rats: potentiation and antagonism by adrenergic agents.

Acetazolamide, a carbonic anhydrase inhibitor, induced right forelimb ectrodactyly in rat fetuses when the mothers were treated on late day 10 and early day 11 of gestation. Coadministration of the selective alpha-1-adrenergic agonist phenylephrine significantly increased the incidence of acetazolamide-induced right forelimb ectrodactyly while failing to induce the lesion when administered alone. Pretreatement with the alpha-adrenergic antagonists phenoxybenzamine and prazosin prevented the phenylephrine-induced increase in right forelimb ectrodactyly. In addition, treatment with either phenoxybenzamine or prazosin in the absence of stimulation with phenylephrine significantly decreased the incidence of acetazolamide-induced ectrodactyly. The results suggest an adrenergic component in acetazolamide teratogenesis. Alterations in uterine blood flow are discussed as a plausible mechanism for the modification of the incidence of ectrodactyly by these adrenergic agents.
Catalytic destruction of ozone by chlorofluorocarbons and partial restoration by methane in large laboratory experiments

Abstract The catalytic destruction of ozone by CFC was quantitatively measured in a large laboratory device which has controlled ultraviolet radiation and gas composition. Experimental results obtained in a pure oxygen atmosphere agreed with theoretical estimates within a factor of two. A destruction ratio of one chloride to 4 × 105 ozone molecules was found. The introduction of methane reduced the density of atomic chlorine resulting in a higher equilibrium ozone density. Even with a methane density six times the CFC density, only partial restoration of ozone is possible.
Stent graft repair in the aortic arch and descending thoracic aorta: A 4-year experience

Abstract Background: Thoracic aortic aneurysms (TAAs) and type B aortic dissections (ADs) are relatively frequent, serious conditions that are often managed nonoperatively because of perceived poor outcome of standard surgical reconstruction. Recently developed stent graft techniques represent a more attractive, less invasive option. We sought to determine the technical feasibility and safety of endovascular repair in the thoracic aorta with a retrospective review of our experience with such an approach. Methods: Forty-seven patients received thoracic stent graft implants during the 4-year period ending March 31, 2002. All patients signed an Institutional Review Board-approved informed consent. Thirty-one patients had TAAs, and 16 had ADs. Device design and implant strategy were on the basis of evaluation of morphology with angiography and computed tomographic scan. The procedures were done with fluoroscopic guidance, with local anesthesia in five cases, spinal anesthesia in 19 cases, and general anesthesia in 23 cases. Endovascular access was achieved with femoral cutdown in 41 cases and a temporary iliac conduit in six cases. A Talent patient-specific device, with 4-mm to 6-mm oversize, was used in all. Proximal endograft attachment was in the descending thoracic aorta in 16 cases, parasubclavian in 21 cases, and the suprasubclavian aorta in 10 cases. Eight patients had adjunctive cervical reconstruction to transpose or revascularize the left subclavian or left common carotid arteries, enabling more proximal endograft attachment in the aortic arch. Results: Access failure occurred in one patient (2.1%). One patient (2.1%) died within 30 days of access-related iliac artery rupture. Another death occurred at 60 days from a ruptured thoracoabdominal aneurysm with type I endoleak. No instances of paraplegia, stroke, or surgical conversion were seen. Five patients (TAA) were found to have endoleak on 30-day computed tomographic scan. Repair of type I endoleak was undertaken in three cases at 1, 4, and 6 months. Eight patients (17%) had adverse events within the first 30 days. Length of follow-up ranged from 1 to 44 months, with a mean of 18 months. Two patients were lost to follow-up, and one withdrew from the study. Four additional mortalities were observed, none related to the endograft or aortic pathology. Conclusion: Stent graft repair of TAA and AD is feasible and can be achieved with technical success and relatively low rates of perioperative morbidity and mortality. The Talent customized design proved versatile in various morphologies. More information is needed on indications, clinical efficacy, and long-term results. (J Vasc Surg 2002;36:1121-8.)
First-principles calculation of the single impurity surface Kondo resonance.

We perform first-principles calculations of the surface and bulk wave functions of the Cu(111) surface and their hybridization energies to a Co adatom, including the potential scattering from the Co. By analyzing the calculated hybridization energies, we find the bulk states dominate the contribution to the Kondo temperature, in agreement with recent experiments. Furthermore, we also calculate the tunneling conductance of a scanning tunneling microscope and compare our results with recent experiments of Co impurities in the Cu(111) surface. Good quantitative agreement is found at short parallel impurity-tip distances ($l6\text{ }\text{ }\AA{}$). Our results indicate the need for a new formulation of the problem at larger distances.
An interesting presentation of a sacrococcygel teratoma with an associated neuroendocrine tumor: A case report

Abstract Teratomas are the most frequently occurring germ cell tumors, with 45–65 percent occurring in the sacrococcygeal region [1]. The case presented below involves a newborn male with a malignant sacrococcygeal teratoma and a number of congenital deformities including a left lower extremity amputation, an absent left kidney, hypoplastic and absent left hemipelvis musculature. After excision of the teratoma and subsequent chemotherapy treatment, the patient returned with a persistent abnormal soft tissue, containing persistent malignant elements around the left femur, suspicious for a neuroendocrine tumor. This case shows a rare association between two exceedingly uncommon malignancies.
Sampling theory for alleles in a random environment.

A MAJOR effort in theoretical population genetics has been aimed at developing statistical tests to distinguish between various explanations of observed patterns of enzyme variation1. Perhaps the most useful result to emerge from this effort is Ewens' sampling theory of neutral alleles2. This theory allows one to use the number and configuration of alleles in a sample to test for departures from neutrality. Watterson3 has derived the analogous sampling distribution for a finite population subject to the joint effects of mutation and symmetric heterotic selection. It differs from the neutral sampling theory, providing a stronger hypothesis-testing situation than has previously been available. In this note I present a third sampling distribution. It applies to an infinite population in which the selective coefficients fluctuate at random through time and space. Quite unexpectedly, the sampling distribution turns out to be identical to that for the neutral model, indicating that agreement of data with Ewens' sampling distribution does not rule out the possibility that natural selection is responsible for the genetic variation in the sample. Furthermore, the properties of random-selection populations at equilibrium are indistinguishable from neutral-allele populations for observations made at a single time point. This result calls into question the claim that agreement of data with predictions of the neutral model argues against natural selection as an important factor for the maintenance of genetic variation.
Noncommutative Symmetric Algebras of Two-Sided Vector Spaces☆

Abstract We generalize the definition of the symmetric algebra of a vector space in order to define noncommutative symmetric algebras of two-sided vector spaces. Not all two-sided vector spaces have noncommutative symmetric algebras; the ones that do are called admissible, and conditions for admissibility are given. Further, for some classes of admissible two-sided vector spaces, the skew fields of fractions of their noncommutative symmetric algebras are computed. The degree 0 components of these skew fields correspond to function fields of certain noncommutative ruled surfaces, and hence allow us to determine birational equivalence classes for such surfaces.
A study of the intertransplantation of gingiva

Abstract This study was undertaken to determine whether any change in morphology can be expected to occur in gingiva transplanted into a zone of alveolar mucosa. Dogs were used as the experimental animals. These were divided into groups of three each and studied over a period of 1 year. Both gross and histologic methods were employed, utilizing measurements and connective tissue stains. Gingiva was transplanted, using a rotated pedicle flap into an adjacent area of alveolar mucosa. The gingival grafts then rested on mobile tissue. Measurements taken before suturing and at subsequent periods over a year disclosed no progressive loss or change in the tissue identifiable as gingiva. Some loss of graft substance occurred in all animals during the first postoperative week. Histologic studies revealed some fragmentation and reorientation of deep collagen fibers in the gingival transplants, but this was not progressive. On the basis of established criteria, the grafted tissue did not undergo a detectable change in morphology despite the altered environment.
Recruitment, survivorship, and Age structure of a New York ribbed mussel population (Geukensia demissa) in relation to shore level: A nine year study

Age structure, recruitment, and survivorship of a Jamaica Bay, New York ribbed mussel (Geukensia demissa) population were studied over nine years at two shore elevations. Mussels were collected in November (following seasonal growth and recruitment) and March (to assay over-winter mortality). Larval recruits (0-class) averaged 55% of the population at the marsh edge compared with <9% at the higher elevation (6 m upshore). High larval settlement at the edge apparently depletes the larval supply available for settlement within the marsh interior. At the edge, the population generally contained 7 monotonically decreasing age classes compared to 15–20 age classes at the interior site. At the interior site, most 0-class mussels may not directly settle into existing mussel aggregations, but instead immigrate over a period of two years following settlement. The linear survivorship curve at the edge reflects 40–50% mortality every year. Over-winter mortality is sensitive to winter ice conditions. Simulations of reproductive output based on survivorship and fertility data combined suggest that mussel cohorts living in the marsh may approach the life time reproductive output of marsh edge mussels after about 15 years, a life span which is not uncommon at higher shore levels.
Newer indications for permanent pacemakers

The role of pacemakers in cardiac disease continues to expand, and recent technology has allowed therapy to be individualized. Newer indications for pacemakers now include long QT syndrome, neurocardiogenic syncope, hypertrophic obstructive cardiomyopathy, and drug refractory atrial fibrillation.
Effect of interfacial forces on polymer blend morphologies

Abstract In this study, the way in which the components of complex polymer blends (those consisting of more than two resins) are segregated after melt processing is described. Depending on the composition of the blend, the dispersed phases are found to remain separated or form more complicated encapsulated structures. The various morphologies which are formed are shown to be consistent with those predicted from an analysis of spreading coefficients.
Ripple formation induced by biogenic mounds

Abstract Bedload and ripple formation at subcritical flows were observed during laboratory studies involving the mound-forming, head-down deposit-feeding polychaete Cistenides gouldii. Flume experiments were designed to investigate the conditions resulting in sediment transport within and immediately downstream of biogenic mound assemblages. Experiments focused on the inputs of mound (population) density, mound height and the presence/absence of Cistenides. The activities of Cistenides may generate sediment transport in two ways: via particle ejection during feeding or via scour generated by their mounds. The first set of experiments were conducted to determine which process was predominantly responsible for ripple formation. Mounds were required for ripple formation, but ripples formed only at the two higher mound densities (150 and 570 per m2). The second set of experiments used mounds of different densities and heights to investigate density effects. One of three final bed states was always attained: (1) mounds became and generated migrating ripples, (2) mounds changed into ripples which did not migrate beyond the test area, called stationary ripples, or (3) mounds remained separate. The division between migrating ripple and no ripple cases was used to develop a threshold similar to that established by Southard and Dingler [Southard, J.B., Dingler, J.R., 1971. Flume study of ripple propagation behind mounds on flat sand beds. Sedimentology, 16, pp. 251–263.] for ripple propagation behind isolated mounds. Our threshold was higher due to the coarser sediments used in this study. Stationary ripples exhibited a `local equilibrium' where, despite a two-fold range of initial mound separation, resulting ripples had similar wavelengths. This stationary ripple wavelength was smaller than the equilibrium wavelength found for migrating ripples generated from a flat bed. The ability of biogenic structures to generate ripples has implications in studies of near-bed processes. Ripples seen in bottom photographs and stratigraphy may not be an absolute indicator of supercritical flows. Additionally, when the topography within patches of mound-building worms changes, the bed geometry generating interfacial flow and bottom drag is ripples instead of mounds. Estimates of reworking due to ripple migration greatly outweigh rates of biological reworking observed in the field. All of these consequences reinforce the importance of sediment transport induced by biogenic structures.
On the behavior of microstructures with multiple length scales

The current study aims to provide fundamental insight into the behavior of microstructures containing grain sizes that span multiple length scales. A commercial 5083 Al alloy was selected as the material of interest to facilitate comparison with recently published data. The materials studied here were prepared via the thermal consolidation of powders that were cryomilled for different times (i.e., 0, 2, 4, and 8 hours). Following consolidation, the resultant microstructure was characterized by an equiaxed grain morphology with a size distribution centered around 200∼300 nm. Dispersed among the 200- to 300-nm grains were coarse-grained regions or ligaments with a grain size ranging from 600 nm to 2 µm. The occurrence of coarse-grained regions is rationalized on the basis of recrystallization or subgrain coarsening, whereas the occurrence of equiaxed fine regions is proposed to be a result of continuous grain growth. Two types of microstructures were selected for study, containing coarse-grained volumes of approximately 28 pct and 43 pct that corresponded to an ultimate tensile strength (UTS) of 566 MPa and 535 MPa, and a fracture strain of 3.2 pct and 3.5 pct, respectively. The observed ductility and the relevant toughening mechanisms were discussed in light of the presence of multiple length scales.
Functional Assembly of Gap Junction Conductance in Lipid Bilayers: Demonstration That the Major 27 Kd Protein Forms the Junctional Channel

Gap junctions isolated from rat liver were incorporated into planar lipid bilayers. A channel activity that was directly dependent on voltage was recorded. Changes of pH and (Ca2+) had no direct effect on channel activity; however, they modulated the voltage-dependent gating of the gap junction channels differently. Single-channel fluctuations showed large scatter with peak amplitudes of 140 and 280 picoSiemmens in 0.1 M NaCl. The major protein of gap junctions (Mr of 27 kd) was also reconstituted into bilayers, giving channel properties similar to those of intact gap junctions. Polyclonal antibodies specific for this protein caused inhibition of the junctional conductance in bilayers. These data provide direct evidence that the 27 kd protein is the molecular species responsible for gap junction communication between cells.
Trimmed estimates in simultaneous estimation of parameters in exponential families

Abstract Let X1,…, Xp be p (≥ 3) independent random variables, where each Xi has a distribution belonging to the one-parameter exponential family of distributions. The problem is to estimate the unknown parameters simultaneously in the presence of extreme observations. C. Stein (Ann. Statist. 9 (1981), 1135–1151) proposed a method of estimating the mean vector of a multinormal distribution, based on order statistics corresponding to the |Xi|'s, which permitted improvement over the usual maximum likelihood estimator, for long-tailed empirical distribution functions. In this paper, the ideas of Stein are extended to the general discrete and absolutely continuous exponential families of distributions. Adaptive versions of the estimators are also discussed.
Characterization of Reactive Dissolution and Swelling of Polymer Films Using a Quartz Crystal Microbalance and Visible and Infrared Reflectance Spectroscopy

Dissolution and swelling of thin films of ionizable polymers in contact with aqueous alkaline solutions are examined using a quartz crystal microbalance, while simultaneously recording the visible reflectivity and infrared absorption of the evolving films. From these data changes in the thickness, depth structure, composition, mass, and mechanical properties of the polymer film during its interaction with the aqueous solution can be detected. Analysis of these provides evidence for the formation of interfacial gel layers resulting from acid−base reaction of the polymer with the hydroxide solution and yields information on the kinetics of transport and chemical reaction that control the overall process. Kinetics simulations indicate that the most important factors influencing observed behaviors are the intrinsic reactivity of ionizable groups on the polymer and the response of the film's mechanical properties, which determine the ability of small molecules to move through it, to incorporation of water.
Comparison of Low-Energy Versus High-Energy Biphasic Defibrillation Shocks Following Prolonged Ventricular Fibrillation

AbstractIntroduction. Since the initial development of the defibrillator, there has been concern that, while delivery of a large electric shock would stop fibrillation, it would also cause damage to the heart. This concern has been raised again with the development of the biphasic defibrillator. Objective. To compare defibrillation efficacy, postshock cardiac function, and troponin I levels following 150-J and 360-J shocks. Methods. Nineteen swine were anesthetized with isoflurane and instrumented with pressure catheters in the left ventricle, aorta, and right atrium. The animals were fibrillated for 6 minutes, followed by defibrillation with either low-energy (n = 8) or high-energy (n = 11) shocks. After defibrillation, chest compressions were initiated and continued until return of spontaneous circulation (ROSC). Epinephrine, 0.01 mg/kg every 3 minutes, was given for arterial blood pressure < 50 mmHg. Hemodynamic parameters were recorded for four hours. Transthoracic echocardiography was performed and t...
Optical study of strained ultrathin films of strongly correlated LaNiO 3

An optical study of fully strained ultrathin ${\mathrm{LaNiO}}_{3}$ films is presented and compared with LDA + DMFT calculations. ${\mathrm{LaNiO}}_{3}$ films were grown by pulsed laser deposition on ${\mathrm{LaAlO}}_{3}$ and ${\mathrm{SrTiO}}_{3}$ substrates which provide compressive and tensile strain, respectively. Optical conductivity data show a Drude peak with a spectral weight that is significantly reduced compared to that obtained from LDA calculations. The extended Drude analysis reveals the presence of a pseudogap around 80 meV for the film on ${\mathrm{SrTiO}}_{3}$ and near 40 meV, at low temperature only, for the film on LAO. An unusual temperature dependence of the optical conductivity is observed, with the Drude plasma frequency increasing by up to 20$%$ at low temperature due to spectral weight transfer from bands lying 2--4 eV below the Fermi energy. Such a strong temperature dependence of the Drude spectral weight has previously been reported for correlated electron systems in which a phase transition is present. In ${\mathrm{LaNiO}}_{3}$, however, no phase transition is observed.
Spatiotemporal reasoning about epidemiological data

Objective: In this article, we propose new methods to visualize and reason about spatiotemporal epidemiological data. Background: Efficient computerized reasoning about epidemics is important to public health and national security, but it is a difficult task because epidemiological data are usually spatiotemporal, recursive, and fast changing hence hard to handle in traditional relational databases and geographic information systems. Methodology: We describe the general methods of how to (1) store epidemiological data in constraint databases, (2) handle recursive epidemiological definitions, and (3) efficiently reason about epidemiological data based on recursive and non-recursive Structured Query Language (SQL) queries. Results: We implement a particular epidemiological system called West Nile Virus Information System (WeNiVIS) that enables the visual tracking of and reasoning about the spread of the West Nile Virus (WNV) epidemic in Pennsylvania. In the system, users can do many interesting reasonings based on the spatiotemporal dataset and the recursively defined risk evaluation function through the SQL query interfaces. Conclusions: In this article, the WeNiVIS system is used to visualize and reason about the spread of West Nile Virus in Pennsylvania as a sample application. Beside this particular case, the general methodology used in the implementation of the system is also appropriate for many other applications. Our general solution for reasoning about epidemics and related spatiotemporal phenomena enables one to solve many problems similar to WNV without much modification.
Racial differences and prognostic significance of tumor location in radical prostatectomy specimens

BACKGROUND Our objective was to evaluate radical prostatectomy specimens for possible racial differences in tumor location, as well as to correlate tumor location with pathologic stage and disease-free survival. METHODS Between January 1991–December 1997, 1,245 patients underwent radical prostatectomy with bilateral pelvic lymphadenectomy for clinically localized prostate cancer. Seven hundred and eighty-five patients who were treated with surgery as monotherapy were evaluated. Tumor location, defined as mainly anterior, mainly posterior, or both (anterior and posterior), was obtained from review of tumor maps prepared from pathological evaluation of completely embedded, resected specimens. RESULTS Overall tumor location was anterior in 107 (14%), posterior in 459 (58%), and both in 219 (28%) cases. The incidence of anterior tumors was higher in African American men compared to Caucasians (16% vs. 11%, P = 0.045). The rate of positive surgical margins in anteriorly and posteriorly located tumors was 60% vs. 38% in African American men (P = 0.001) and 48% vs. 27% in Caucasians (P = 0.001), respectively. African American men were found to have a higher incidence of positive surgical margins (50%; 174/348) compared to Caucasian men (34%; 150/437; P = 0.001). CONCLUSIONS Anterior tumors were present in 14% of our patients. African American men have a greater percentage of anterior tumors than do Caucasians. In addition, a higher rate of positive surgical margins was encountered in patients with anterior tumors, especially if they were African American men. In patients with an abnormal serum prostate-specific antigen level and negative sextant prostate biopsies, we recommend biopsy of the anterior zone of the prostate. Prostate 37:230–235, 1998. © 1998 Wiley-Liss, Inc.
Roton-pair creation by electron bubbles in helium

Electrons in superfluid helium form cavities that displace hundreds of atoms. These ``electron bubbles'' characteristically emit rotons in pairs when accelerated by an electric field. As no symmetry prevents the emission of single rotons, this has long been a mystery. We use a recent theory, which correctly predicts roton pair emission, to calculate its rate. The values that we obtain are four orders of magnitude smaller than experiment. This discrepancy can be linked to tunneling amplitudes associated with the bubble geometry that are sensitive to details of the helium wave function.
Numerical simulation of UWB impulse radar vital sign detection at an earthquake disaster site

Using the finite difference time domain (FDTD) numerical simulation approach and synthetic computational experiments we investigated the use of the ultra-wide band (UWB) radar technique for human vital sign detection under collapsed building debris caused by catastrophic earthquakes. The model of the collapsed building was developed based on a real situation from an earthquake disaster site. The model consists of two human beings with different characteristics of vital signs, i.e., with different cardio-respiration features, posed in different positions, and buried at different depths in the debris. Analysis of the synthetic data indicates that the UWB impulse radar can identify and separate the human subjects' vital sign for a radar record as short as 20s. The simulation approach was verified with a physical experiment using impulse UWB radar with two human subjects positioned behind a concrete wall. Advanced signal processing of source separation and signal processing using empirical mode decomposition were conducted to identify and locate the human subjects. The results show that this approach is a promising technique for search and rescue of living victims at disaster sites.
Distribution of the serotonin 2C (5HT2C) receptor gene -759C/T polymorphism in patients with schizophrenia and normal controls.

Background In patients with schizophrenia, the percentage of patients with diabetes has been found to be twice that of the normal population. The risk factors for this higher rate are unknown, although dietary, lifestyle, and genetic factors have all been suggested. Recently, a polymorphism (-759C/T) in the serotonin 2C (5HT2C) receptor promoter region has been associated with the development of diabetes in a normal control population, with the frequency of the T allele being higher in subjects without diabetes. Aim To determine whether the distribution of the -759C/T polymorphism of the 5HT2C receptor is different among patients with schizophrenia and normal controls. Methods DNA from 100 patients with schizophrenia and 81 normal controls were analyzed for the 5HT2C receptor -759C/T polymorphism to determine its allelic frequencies in these two groups. Results Using a chi-squared analysis, no statistical differences in the distribution of C alleles and T alleles were found between the two groups (P=0.2931). Conclusions Patients with schizophrenia have a higher risk for developing diabetes than the general population. We did not find a higher distribution of the -759T allele of the 5HT2C receptor in normal controls compared with in patients with schizophrenia. This suggests the higher prevalence of diabetes in schizophrenia is not due to this polymorphism.
Ectopic Hepatic Tissue Presented as a Posterior Mediastinal Mass

We present a young patient with respiratory complaints that was found to have a mass in her right posterior mediastinum. The mass was diagnosed to be ectopic histologically unremarkable hepatic tissue. We have also reviewed several of the few intrathoracic ectopic liver cases in the literature, along with a brief discussion of the significance of such a finding.