cssi/SciSciGPT-SciSciNet huggingface dataset:
Time-domain analysis of cross-correlation for multitarget/multipath time delay estimation

This paper analyzes the effect of source separation on the estimation accuracy of the TDOA of multiple exponentially autocorrelated signals at two sensors in white noise. The analysis is carried out for uncorrelated signals (separate sources) as well as unity correlated signals, as in multipath propagation from a single source. The estimates are obtained from cross-correlations based on moving average samples of the noisy signals from the two sensors. The effect of the source separation on the degradation ratio is evaluated and compared with the optimal processor. The theoretical performance is verified through simulations for different SNRs and time-bandwidth products. Another advantage of the technique is that it avoids ambiguities in the cross-correlation. >
INFLUENCE OF TEMPERATURE AND SOLAR RADIATION ON PERSISTENCE OF VITAMIN B12 , THIAMINE, AND BIOTIN IN SEAWATER(1).

Ecologically important concentrations of vitamin B12 and thiamine in charcoal-treated, filter-sterilized seawater stored in the dark at 5, 18, 28, and 37 C generally did not change over a 9-week period, although there was some breakdown of B12 at 37 C. Biotin activity under similar conditions generally increased, indicating its decomposition to more active products. Solutions kept at-20 C had unchanged vitamin activity. B12 and biotin in seawater exposed to sunlight were rapidly destroyed. The course of thiamine destruction in sunlight indicated a breakdown to a stable, biologically active product(s)).
In vivo assessment of left ventricular remodelling after myocardial infarction by digital video contrast angiography in the rat

Objective: The aim was to develop a digital video contrast angiographic method for assessing global left ventricular function and volume in vivo in the rat and then to apply it to a study of ventricular remodelling after coronary occlusion, with and without reperfusion. Methods: Digital contrast angiography was performed on 29 rats, including the following groups: sham operated (n=11), non-transmural myocardial infarction produced by reperfusion (n = 8), and transmural infarction produced by permanent occlusion (n= 10). Under anaesthesia three weeks later, biplane fluoroscopic images were acquired following venous contrast injection. Levophase images were digitised, and left ventricular end diastolic and end systolic volumes and ejection fractions were obtained using an area-length method. Left ventricular ejection fraction data also were calculated by videodensitometry from video density curves. Results: Compared to the sham operated group, the reperfused group showed a significant decrease in left ventricular ejection fraction, at 53(SD 7) v 70(5)% (p<0.01), and an increase in end diastolic volume. The permanent occlusion group showed a further decrease in the ejection fraction [40(8)%] and a further significant increase in end diastolic volume compared to the reperfused group (p<0.01). Left ventricular ejection fraction correlated inversely with percent infarct size (r = 0.882) and showed a positive correlation with the spared epicardial area (r = 0.721). Most haemodynamic variables, including maximum left ventricular dP/dt, failed to discriminate between the groups. The methods showed reasonable accuracy when tested in vitro using contrast filled balloons. In vivo, the left ventricular ejection fraction calculated by densitometry showed adequate interobserver variability (2 SD ± 8.5 percentage points), but the area-length method showed somewhat more scatter. Conclusions: Digital video contrast angiography is a feasible method for the assessing global left ventricular function in the rat and should be useful in other small animal models. Significant differences in left ventricular volumes and ejection fractions were detected between reperfused and permanent occlusion groups, whereas haemodynamic variables showed non-significant trends. Reperfusion after 45 min of occlusion caused sparing of the epicardium, prevented unfavourable remodelling, and improved the ejection fraction compared to permanent occlusion. Cardiovascular Research 1994; 28 :349-357
Assessing the impact of PACS on patient care in a medical intensive care unit

In this paper we have present data from pilot studies to estimate the impact on patient care of an intensive care unit display station. The data were collected during two separate one-month periods in 1992. We compared these two different periods in terms of the relative speeds with which images were first viewed by MICU physicians. First, we found that images for routine chest radiographs (CXRs) are viewed by a greater number of physicians and slightly sooner with the PACS display station operating in the MICU than when it is not. Thus, for routine exams, PACS provide the potential for shortening of time intervals between exam completions and image-based clinical actions. A second finding is that the use of the display station for viewing non-routine CXRs is strongly influenced by the speed with which films are digitized. Hence, if film digitization is not rapid, the presence of a MICU display station is unlikely to contribute to a shortening of time intervals between exam completions and image-based clinical actions. This finding supports the use of computed radiography for CXRs in an intensive care unit.
CO oxidation with Pt(1 1 1) supported on pure and boron-doped carbon: A DFT investigation

Abstract Previous density functional theory calculations of Pt and PtRu clusters on carbon supports have shown that the adsorption energies of these metal clusters increase substantially with substitutional boron defects in the carbon lattice. The strong interactions with the support may also influence the catalytic activity of the deposited metal. In order to investigate the possible catalytic influence of different carbon supports, CO oxidation is used as a probe reaction, and the catalytic properties of supported Pt are analyzed using density functional theory (DFT). In the DFT calculations, both carbon-supported and unsupported Pt(1 1 1) surfaces are modeled, and the influence of the carbon support with and without substitutional boron dopants is analyzed. Although the boron dopants increase the Pt-support binding energy by approximately 60 kcal/mol, the support-induced effects on the catalytic behavior of Pt are minimal. The catalytic properties of Pt with various supports converge after approximately six to nine layers of Pt. These results give initial indication that support-induced catalytic effects from carbonaceous materials may be neglected, even when the interactions with the support are significant.
Microsurgical excision of colloid cyst with favorable cognitive outcomes and short operative time and hospital stay: operative techniques and analyses of outcomes with review of previous studies.

Objective Microsurgical and endoscopic colloid cyst excision differ with regard to operative time, length of hospital stay, and extent of resection. Methods A retrospective review of a single surgeon's microsurgical colloid cyst resection in 10 consecutive patients was performed. Cyst size, hydrocephalus, symptoms, operative time, postoperative stay, complications, and objective testing of memory, concentration, calculation, and attention (cognition), along with performance at job, were noted. Results All 10 patients had complete excision. Mean cyst size, mean operative time, and median postoperative stay were 1.6 cm, 124 minutes, and 3.5 days respectively. The mean operative time from cyst visualization to complete excision was 18 minutes. Follow-up ranged from 6 to 111 months (mean, 49.5 months). There were no recurrences; symptoms (headache, visual and balance problems) improved significantly in 70%. Postoperative cognitive performance, including memory, was the same in 8 patients (5 of whom had preoperative memory problems) and worse in 2 patients who had no preoperative memory problems. The bone flap was removed in 1 patient for wound dehiscence. Hemiparesis in another patient, seen immediately after surgery, completely resolved before discharge. One patient with loculated ventricles and multiple previous shunt revisions had unresolved hydrocephalus after cyst excision. Conclusion We report the very short operative times and postoperative stay for microsurgery, which are comparable to some endoscopic series. We also report results of objective tests of cognitive performance. With adoption of a callosal incision of 1 cm or less, meticulous dissection around the fornix, and complete excision, acceptable long-term cognitive function and functional performance were achieved. Our results support the microsurgical approach. A larger sample size can more conclusively establish whether it should be chosen over the endoscopic technique.
Effect of Lanthanide Ions on Dynamic Nuclear Polarization Enhancement and Liquid State T1 Relaxation

In the dynamic nuclear polarization process, microwave irradiation facilitates exchange of polarization from a radical's unpaired electron to nuclear spins at cryogenic temperatures, increasing polarization by >10,000. Doping samples with Gd3+ ions further increases the achievable solid-state polarization. However, on dissolution, paramagnetic lanthanide metals can be potent relaxation agents, decreasing liquid-state polarization. Here, the effects of lanthanide metals on the solid and liquid-state magnetic properties of [1-13C]pyruvate are studied. The results show that in addition to gadolinium, holmium increases not only the achievable polarization but also the rate of polarization. Liquid-state relaxation studies found that unlike gadolinium, holmium minimally affects T1. Additionally, results reveal that linear contrast agents dissociate in pyruvic acid, greatly reducing liquid-state T1. Although macrocyclic agents do not readily dissociate, they yield lower solid-state polarization. Results indicate that polarization with free lanthanides and subsequent chelation during dissolution produces the highest polarization enhancement while minimizing liquid-state relaxation. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.
Collaboration and Power Allocation for Distributed Estimation in Clustered Wireless Sensor Networks

We consider the problem of distributed estimation in a power constrained collaborative wireless sensor network (WSN), where the network is divided into a set of sensor clusters, with collaboration allowed among sensors within the same cluster but not across clusters. Specifically, each cluster forms one or multiple local messages via sensor collaboration (in particular, linear operation is considered) and transmits the messages over noisy channels to a fusion center (FC). The final estimate is constructed at the FC based on the noisy data received from all clusters. In this collaborative setup, we study the following fundamental problems. Given a total transmit power constraint, shall we transmit the raw data or some low-dimensional local messages for each cluster? What is the optimal collaboration scheme for each cluster? How to optimally allocate the power among different clusters? These questions are addressed in this paper.
Hidden fermions in Z(2) theories

I show that Ising models and $Z(2)$ gauge theories, in any number of dimensions, are equivalent to systems of fermions with local interactions only. This is done in the Hamiltonian formalism by rewriting the Hamiltonians in terms of locally coupled fermion operators. One advantage of the fermionic formalism is that duality transformations become trivial. All unsolved models have products of four or more fermion operators as terms in their Hamiltonians.
Hexose transport in undifferentiated and differentiated BALB/c 3T3 preadipose cells: Effects of 12–0‐tetradecanoylphorbol‐13‐acetate and insulin

The effect of the phorbol diester 12-0-tetradecanoylphorbol-13-acetate (TPA) on hexose transport in undifferentiated and differentiated BALB/c 3T3 preadipose cells was studied. Additon of TPA to undifferentiated or fully differentiated cultures resulted in an increased rate of both 2-deoxyglucose uptake and 3-0-methylglucose transport; the time course and maximal stimulation differed for each type of culture and for each hexose. In confluent, undifferentiated cells, half-maximal stimulation of 2-deoxyglucose uptake occurred at 3 nM TPA, while the half-maximal stimulation of 3–0-methylglucose occurred at 30 nM. Epidermal growth factor and fetal bovine serum increased 2-deoxyglucose uptake in undifferentiated cells, while insulin did not. Insulin did, however, stimulate 3–0-methylglucose transport in differentiated cells. From dose-response curves in differentiated cells, halfmaximally effective concentrations were 0.17 nM for insulin and 30 nM for TPA. At optimal concentrations and incubation times for each, TPA was significantly more effective than insulin in stimulating hexose transport in differentiated cells. It was also shown that insulin could further increase hexose transport in maximally stimulated TPA-treated cells. Cycloheximide inhibited by 75% the increase in hexose transport by TPA in differentiated cells, while having no effect on the response of these cells to insulin. In differentiated cells, chronic exposure to insulin abolished the ability of these cells to respond acutely to insulin addition but they could still respond to TPA. On the other hand, differentiated cells exposed continuously to TPA for 5 days retained the ability to activate 3–0-methylglucose transport after either TPA or insulin addition. These results demonstrate that TPA can stimulate hexose transport directly in both undifferentiated and differentiated 3T3 cells and suggest that TPA and insulin affect transport by different mechanisms.
Self‐Regulatory Strategies and Agency in Self‐Instructed Language Learning: A Situated View

Individualized instruction, a form of materials-centered self-instruction, has a long, undocumented history in the United States. The context of individualized instruction requires learners to regulate their own learning processes, including their emotional responses to learning. This study offers a situated view of the processes and strategies learners use to manage the self-instructional process. Findings of this study suggest that contextual factors such as learners' self-beliefs and social support influence the kinds of strategies that learners employ. Moreover, self-regulation of learning in this context required that learners (a) structure the learning environment to meet their needs and (b) manage their emotional responses to individualized language learning. [ABSTRACT FROM AUTHOR]
Predictors Of Post-Traumatic Stress Disorder Following Severe Injury

The chronicity and morbidity of established post-traumatic stress disorder (PTSD) has stimulated interest in recognizing and understanding the early development of the disorder. Acute stress disorder, a new diagnosis intended to facilitate early case detection, rests on the occurrence of dissociative reactions. It remains uncertain whether dissociation is a universal or unique early predictor of subsequent PTSD. Traumatic injury is an important and relatively understudied antecedent of PTSD. The objective of this study was to preliminarily identify which previously implicated early reactions and risk factors would apply to the prediction of PTSD following severe traumatic injury. Patients admitted to a regional Level I trauma center following life threatening events who had recall of the incident and did not have signs of traumatic brain injury or recent psychopathology were enrolled. Comprehensive assessments were conducted during hospitalization and after discharge approximately 2 months after the traumatic event. At follow-up, 24% of the available 50 subjects met full criteria for PTSD and an additional 22% met criteria for two of three symptom clusters. Early symptoms of heightened arousal and coping with disengagement were independent predictors of PTSD severity at follow-up. Relationships to initial dissociative reactions and a diagnosis of ASD were not significant. These early predictors found in a setting of severe injury only partially overlap findings from previous PTSD studies. Depression and Anxiety 14:226–231, 2001. © 2001 Wiley-Liss, Inc.
Evaluation of the thoracic and lumbar spine after blunt trauma

Abstract Background : Routine performance of thoracolumbar (TL) spinal radiology in patients with blunt trauma is controversial. Patients and methods : To establish indications for radiologic screening of the TL spine, a retrospective review of 344 patients who had radiologic evaluation of the spine was performed. Results : Forty-seven patients had abnormalities detected on radiologic evaluation. One hundred eighty-six patients had at least one clinical finding suggestive of injury. Thirty-two had abnormal radiographs. Thirteen of these abnormalities represented old or minor fractures and were not treated. Nineteen patients had injuries requiring treatment. Two patients were treated with activity restriction, 12 with a back brace, 4 with operative fixation, and 1 patient died prior to operation. Of the 129 patients who were awake, alert, and without clinical evidence of injury, 10 had abnormal radiologic studies. Three patients had old fractures, 4 had transverse process fractures, and 3 had spondylolisthesis. None of these patients required treatment. Twenty-nine patients had equivocal clinical examinations primarily due to altered levels of consciousness. Five patients had abnormal radiologic studies, 3 of whom required treatment. Three factors associated with the occurrence of TL spine injury were identified: an injury Severity Score ≥15, a positive clinical examination, and a fall of ≥10 feet. Conclusions : These data suggest that patients who are awake, alert, and with no clinical evidence of injury do not require radiologic study of the TL spine. Patients with equivocal or positive clinical findings or with altered levels of consciousness should have complete TL spine evaluation.
Treatment of hyperammonemic coma caused by inborn errors of urea synthesis

The relative effectiveness of exchange transfusion, peritoneal dialysis, arginine, and sodium benzoate was evaluated during 44 episodes of hyperammonemic coma in 31 patients with congenital urea cycle enzymopathies. The overall survival rate was 56%. In 15 episodes treated with EXT the fall in ammonium was 19±24%, P >0.05. In 30 episodes treated with PD, the fall in ammonium was 60±9%, P
Potential mechanisms for the regulation of growth factor binding by heparin.

Heparin and heparan sulfate proteoglycans (HSPG) bind many soluble growth factors and this binding is now recognized as an important mechanism for modulation of cell activity. Fibroblast growth factor-2 (FGF-2) is one of the best characterized of the heparin-binding growth factors and it has been shown experimentally that heparin regulation of FGF-2 activity is dependent on the level of cell HSPG and the concentration of heparin. In this paper, we explore, using mathematical modeling, proposed mechanisms for heparin regulation and determine how they impact FGF receptor binding. We demonstrate that the experimentally observed receptor binding phenomena can be reproduced if cells (1) express heparin-binding cell surface molecules and if either (2) these heparin binding sites are FGFR and bind heparin and FGF-2-heparin complexes or (3) are surface molecules able to bind FGF-2 and couple with FGF-2 receptors to form high-affinity FGF-2-bound surface complexes. The ability of heparin to directly interact with the FGFR and bind FGF-2 in the absence of this coupling function was not sufficient to explain heparin activity. These findings have implications with regard to regulation of heparin-binding growth factors and could help guide the development of highly specific growth regulatory molecules through specific regulation by heparin and HSPG.
Picosecond time-resolved S2→S0 fluorescence of xanthione in different fluid solvents

Time-correlated single-photon counting experiments at ≈ 25 ps resolution have been used to measure the S2 fluorescence decay time of xanthione in different fluid solvents. Systematic differences in S2 lifetime in the range 20–30 ps are revealed for a homologous series of n-alkane solvents, and an increase in lifetime for extensive chain branching is also noted. Solutions of xanthione in aromatic solvents and in alcohols are found to exhibit fluorescence decay limes < 20 ps. Little evidence is seen which would support a nonradiative relaxation mechanism involving Franck-Condon selective energy transfer to high-energy vibrational modes of the solvent. Instead, the current results provide support for a mechanism in which a reversible solvent-solute chemical reaction, probably involving bond insertion, is responsible for the solvent dependence of the S2 fluorescence decay time.
The Effect of Increasing Total Parenteral Nutrition on Protein Metabolism

We asked the question, if the amount of nutrients given parenterally is progressively increased, does the rate of whole body protein synthesis rate increase correspondingly and how does the protein breakdown rate change? Eight malnourished patients requiring total parenteral nutrition (TPN) were studied. We measured their whole body protein synthesis and breakdown rate four times at intervals of 3 days using 15N glycine as the tracer. The first study was done pre-TPN. The 2nd, 3rd, and 4th studies were done at increasing TPN rates. The rates were TPN 1, 1440 kcal/day and 7.9 g/N/day; TPN 2, 2160 kcal/day and 11.9 g/N/day; TPN 3, 2880 kcal/day and 15.8 g/N/day. The protein synthesis rate initially increased as the amount of TPN was increased, but increasing the rate from TPN-2 to TPN-3 did not result in further increase. Increasing the rate of TPN above a certain level does not lead to a concomitant increase in the protein synthesis rate.
Insulin-like growth factor-binding protein-2 concentrations in cerebrospinal fluid and serum of children with malignant solid tumors or acute leukemia

Many tumor cell lines express insulin-like growth factors (IGFs) as autocrine growth factors and IGF-binding protein-2 (IGFBP-2) as a major IGFBP, which, in turn, regulates the bioavailability and bioactivity of IGFs. The aim of our study was to investigate 1) whether children with malignancies have elevated IGFBP-2 levels in cerebrospinal fluid (CSF) and serum, and 2) whether IGFBP-2 levels in these biological fluids could be useful markers for the diagnosis and follow-up of certain tumor types. We, therefore, measured IGFBP-2 levels in the CSF and serum of children with malignancies by Western ligand blot analysis; RIA with alpha IGFBP-2, a polyclonal antibody for human IGFBP-2; and immunoprecipitation with alpha IGFBP-2 and alpha Hec-1a, a polyclonal antibody that recognizes IGFBP-2 and -3. Furthermore, the expression of IGFBP-2 messenger ribonucleic acid in tumor tissue from three central nervous system (CNS) tumor patients was analyzed by Northern blot analysis. We examined CSF from 21 children with ...
Involvement of spinal kappa opiod receptors in the antagonistic effect of dynorphins on morphine antinociception

The modulatory effects of intrathecally (i.t.) administered dynorphin A(1-17) and dynorphin A(1-13) on morphine antinociception have been studied previously in rats by other investigators. However, both potentiating and attenuating effects have been reported. In this study, the modulatory effects of i.t. administered dynorphin A(1-17) as well as the smaller fragment, dynorphin A(1-8), were studied in mice. In addition, nor-binaltorphimine (nor-BNI), a highly selective kappa opioid receptor antagonist, and naltrindole (NTI), a highly selective delta opioid receptor antagonist, were used to characterize the possible involvement of spinal kappa and delta opioid receptors in the modulatory effects of the dynorphins. Dynorphin A(1-17) and dynorphin A(1-8) administered i.t. at doses that did not alter tail-flick latencies, were both able to antagonize in a dose-dependent manner, the antinociceptive action of s.c. administered morphine sulfate. The antinociceptive ED50 of morphine sulfate was increased 3.9- and 5.3-fold by 0.4 nmol/mouse of dynorphin A(1-17) and dynorphin A(1-8), respectively. Injections of 0.4 and 0.8 nmol/mouse of nor-BNI i.t., but not its inactive enantiomer (+)-1-nor-BNI, inhibited dose-dependently the antagonistic effects of the dynorphins. These doses of nor-BNI alone did not affect the antinociceptive action of morphine sulfate. Intrathecal administration of 5 nmol/mouse of NTI also did not affect the modulatory effects of dynorphins. These observations that dynorphins exert their antagonistic effects on morphine-induced antinociception stereoselectively through spinal kappa opioid receptors may suggest a coupling between spinal kappa and mu opioid receptors.
Protein phosphatase 2A and DNA-dependent protein kinase are involved in mediating rapamycin-induced Akt phosphorylation.

Inhibition of mammalian target of rapamycin complex 1 (mTORC1), for example with rapamycin, increases Akt phosphorylation while inhibiting mTORC1 signaling. However, the underlying mechanisms have not been fully elucidated. The current study has uncovered a previously unknown mechanism underlying rapamycin-induced Akt phosphorylation involving protein phosphatase 2A (PP2A)-dependent DNA protein kinase (DNA-PK) activation. In several cancer cell lines, inhibition of PP2A with okadaic acid, fostriecin, small T antigen, or PP2A knockdown abrogated rapamycin-induced Akt phosphorylation, and rapamycin increased PP2A activity. Chemical inhibition of DNA-PK, knockdown or deficiency of DNA-PK catalytic subunit (DNA-PKcs), or knock-out of the DNA-PK component Ku86 inhibited rapamycin-induced Akt phosphorylation. Exposure of cancer cells to rapamycin increased DNA-PK activity, and gene silencing-mediated PP2A inhibition attenuated rapamycin-induced DNA-PK activity. Collectively these results suggest that rapamycin induces PP2A-dependent and DNA-PK-mediated Akt phosphorylation. Accordingly, simultaneous inhibition of mTOR and DNA-PK did not stimulate Akt activity and synergistically inhibited the growth of cancer cells both in vitro and in vivo. Thus, our findings also suggest a novel strategy to enhance mTOR-targeted cancer therapy by co-targeting DNA-PK.
Radio Iodine Uptake in Humans. V. Absolute Determination of Radio-iodine in the Thyroid

SummaryA method of counting at a distance over the thyroid was used in animal and human subjects. This method involves the shielding of the Geiger counter tube from all radiation except the thyroid gland, by enclosing the counter in a long lead tube opening over the thyroid. The statistical error inherent in long distance counting is thereby effectively reduced. Independent beta assays were done on the thyroids of 5 dogs and 1 human adult who were subjected to total thyroidectomy immediately after counting with the above technic. Comparison of radioactivity of these glands, as determined by beta assays and by long distance gamma counting, showed a maximal deviation of the order of 20%, with the majority agreeing within about 5%.Suggestions are made regarding improvement of in vivo measurements such as employed in this technic.
Police and domestic dog bite injuries: What are the differences? What are the implications about police dog use?

Summary Background Despite the widespread use of police dogs, there is very little objective medical information about the injuries they cause when they bite. Our aim was to statistically describe police dog bite injuries. Methods We described police dog bite injuries by comparing them with domestic (non-police) dog bites. We retrospectively analyzed their demographic and specific injury data drawn from their medical records. The police dog bite victims came from the Los Angeles Police Department K9 Unit from 1988 to 1990. The domestic dog bite victims came from King-Drew Medical Center, an inner-city public hospital from 1989 to 1996. All of the police dog victims’ medical records that could be located were included (595 out of 957). All domestic dog bite victims that arrived for treatment were included (n = 1109). Results Police dog bite victims were usually bitten multiple times, whilst domestic bite victims were not. Police dog bite victims were bitten more often in the head, neck, chest and flank. They were hospitalised more often, underwent more operations and had more invasive diagnostic tests. Conclusions Police dog bite injuries appeared to be more serious than victims of domestic dog bite victims. The reasons for the differences were related to the types of dogs selected and their special training.
Agmatine: An Endogenous Ligand at Imidazoline Receptors Is a Novel Neurotransmittera

Agmatine, an amine and organic cation, is an endogenous ligand at alpha 2-adrenergic and imidazoline (I-) receptors, to which it binds with high affinity. In addition, agmatine has properties of an endogenous neurotransmitter. Thus, agmatine (a) is locally synthesized in brain by a specific enzyme, arginine decarboxylase; (b) is stored in a large number of neurons with selective distribution in the CNS; (c) is associated with small vesicles in axon terminals that, at least in hippocampus, make synaptic asymmetric (excitatory) synapses on pyramidal cells; (d) is released from synaptosomes in a Ca(2+)-dependent manner; (e) can be enzymatically degraded by agmatinase in synaptosomes; (f) can be inactivated by selective reuptake; (g) blocks the ligand-gated NMDA receptor channel at sites distinct from ligand-binding and polyamine sites; and (h) has systemic actions when administered intraventricularly. Additionally, (i) agmatine is a precursor of brain putrescine and, hence, of higher polyamines, and (j) it competitively inhibits the activity of all isozymes of nitric oxide synthase. Agmatine meets most criteria to establish it as a novel neurotransmitter/neuromodulator in the CNS. However, agmatine differs from forms of clonidine displacing system with respect to distribution, bioactivity, and capacity to interact with antibodies raised to imidazoline-like drugs. Thus, there are multiple endogenous ligands of the imidazoline receptors, one of which is agmatine.
Circumventing the Challenges of Fuel Cell Powered Automobiles

The purposes of this paper are (1) to examine the realities of fuel cell development to determine the economic potential of fuel cell applications to transportation and (2) to identify the major challenges as well as the public policies that could lead to the automobile becoming a mobile electric power source that is used to power homes and industry. Several technical and cost issues were identified to have the potential to pose development challenges; however, none are likely to be show-stoppers. If the fuel cell powered vehicle can offer the consumer additional uses for the automobile, e.g., a source of electric power for businesses or it can permit a rapid style change in the automobile by easily replacing the passenger compartment at costs the consumer finds acceptable, the consumer will be willing to spend more on the fuel cell powered vehicle than it spends on combustion engine powered vehicles. If the fuel cell stimulates design changes that makes major contributions to the safety of automobiles and results in substantial reductions in the cost of insurance, that will also promote consumer interest. Of equal importance to these technical issues are public policies that could promote fuel cell power use in automobiles. For example, a desire to reduce our dependence on foreign sources of oil or rapid growth in oil prices could lead to pubic policies that would accelerate the adoption of fuel cells in automobiles.Copyright © 2003 by ASME
An Empirically Keyed Scale for Measuring Managerial Attitudes toward Women Executives.

A scale (MATWES) is presented providing reliability and some validity measures regarding managerial attitudes toward women executives. Methodology used demonstrates an empirical approach to scale development through the employment of a projective test for item generation and the use of a panel of women executives who served as Q-sorters to select the items. The use of the Scale as a research instrument and its value in minimizing researcher bias in its construction are discussed.
Satellite formation design in orbits of high eccentricity with performance constraints specified over a region of interest: MMS phase II ☆

Abstract The formation design problem for Phase II of the Magnetospheric Multiscale (MMS) mission is addressed using differential mean orbital elements as design variables and the Gim–Alfriend state transition matrix for relative motion propagation. The MMS mission requires a formation of four satellites in a nearly regular tetrahedron throughout a Region of Interest (RoI), defined near apogee of a highly eccentric orbit. Previous papers have addressed the problem of formation design with performance constraints specified over a RoI, and these methods are now applied to the present problem. In addition, the use of a modified along-track drift condition as a constraint to ensure long-term formation stability is investigated. The performance of the designed formations in the presence of differential semimajor axis errors is also examined. Finally, the results are verified using the NASA General Mission Analysis Tool.
Structure and stability of small compact self-interstitial clusters in crystalline silicon

We have determined the atomic structure and formation energies of small, compact self-interstitial clusters $({I}_{n},n\ensuremath{\leqslant}10)$ in Si using a combination of Metropolis Monte Carlo, tight binding molecular dynamics, and density functional theory calculations. We present predicted local-minimum configurations for compact self-interstitial clusters with $n=5\char21{}10$, together with well-defined smaller clusters $(n\ensuremath{\leqslant}4)$ for comparison. The cluster formation energies per interstitial exhibit strong minima at $n=4$ and 8.
Child temperament in three U.S. cultural groups

Le temperament des enfants (N = 111 enfants de vingt mois) issus de trois milieux culturels differents aux Etats-Unis (latino americain, japonais american et d'origine europeenne) a fait l'objet d'une recherche. Comme l'indique une perspective de biocomportement universaliste sur l'expression du temperament precole, on a trouve peu de differences de groupe dans le temperament de l'enfant, quelqu'ait ete le milieu culturel. Cependant, des facteurs lies aux rapports maternels du temperament de l'enfant a differe d'une groupe culturel a l'autre. Les resultats presentent un apercu general de la nature du temperament de l'enfant et plus specifiquement du temperament des enfants issus de familles immigrees ainsi que du parentage dans ces familles immigrees.
Canine cemented total hip replacements: state of the art.

Total hip replacements in the dog have become well established over the past 20 years as an effective method for treating disabling hip conditions. A fixed head prosthesis has been the mainstay during most of this period. Return to normal function with this prosthesis has been reported at 95 per cent. Although patient selection, pre- and post surgical care, the surgical technique and the treatment or prevention of complications has been continually improved, it was not until recently that the prosthesis and its instrumentation were improved. Now a modular prosthesis with improved instrumentation gives the veterinary surgeon ‘state of the art’ implants and instruments. The prosthesis is easier to implant, the surgeon has greater flexibility in surgery and improved results are expected. Total hip replacement continues to be an effective way to give dogs a pain-free, mechanically sound hip joint.
“Spontaneously” hypertensive mice: A potential genetic model for the study of the relationship between heart size and blood pressure

Abstract Mice selected genetically for high and low blood pressure (BP) were compared with regard to heart weight and heart/body ratios. Two experiments were performed with mice ranging in age from 1.3 to 9 months and 11 to 23 months respectively. In a third experiment C57BL/6J mice were compared to the high and low BP mice. Heart/body ratios and heart weights, adjusted for body weight via covariance analysis, were significantly greater for the high BP mice, but no Age x BP Genotype interaction was observed. Results were discussed in terms of a possible relationship between heart weight and BP via genetic linkage or pleiotropy. The possibility was also raised that compensatory mechanisms for high blood pressure, e.g., cardiac hypertrophy, may operate very early in development for animals who are hypertensive by virtue of selective breeding for blood pressure extremes.
The secondary refrigerant freezing process: A modeling study

Abstract The secondary refrigerant freezing process has been described by mathematical models of the major system components. The mathematical equations were used with the aid of a computer to study the operational-design economics of a freezing process and to predict the best operating conditions. Optimization computations showed that the economics of process operation depend largely on the temperature maintained in the freezer and the overall difference in refrigerant and equilibrium freezing temperature. The effect of departures from optimal design are assessed. An analysis of the linearized freezer dynamic equations showed the freezer to be stable and did not indicate regions of difficult control.
Ten New Species of Tibouchina (Melastomataceae) from Mexico

Ten new species of Tibouchina (T. almedae, T. congestiflora, T. connata, T. hintonii, T. macvaughii, T. nanifolia, T. patens, T. roseotincta, T. sinaloensis, andT. thulia) are described from western Mexico. Distinguishing characteristics, phenology, distribution, and phylogenetic relationships are discussed. Illustrations of all these new species are provided.
Time dependent alterations in dopamine tissue levels and metabolism after experimental traumatic brain injury in rats.

Abstract Several studies have demonstrated alterations in the dopamine (DA) system after traumatic brain injury (TBI). The present study investigated the temporal changes in DA tissue levels and metabolism at 1-h or 1, 7, 14, and 28 days after cortical impact or sham injury in rats. DA and DOPAC levels were measured by HPLC in the frontal cortex (FC) and striatum. DA levels were significantly increased at 1 h in the contralateral FC and at 1 day in the ipsilateral FC versus respective sham groups. DA and DOPAC levels were significantly increased bilaterally at 1 h in the striatum versus sham. These data indicate that TBI induces an early increase in DA and DOPAC, which returns to sham levels over time.
QUENCHING MECHANISMS AND KINETICS OF CAROTENOIDS IN RIBOFLAVIN PHOTOSENSITIZED SINGLET OXYGEN OXIDATION OF VITAMIN D2

The oxidation of vitamin D2 in a solution of 12% water, 88% acetone and 15 ppm ribqflavin under light or dark was studied by measuring the headspace oxygen. Ribofiavin accelerated the oxidation of vitamin D2 by singlet oxygen under light, but did not affect vitamin D2 oxidation under dark. Quenching mechanisms and kinetics within the range of 0–20 ppm β-cawtene or fucoxanthin and with 0–80 ppm retinyl acetate or retinol on 15 ppm riboflavin photosensitized singlet oxygen oxidation of vitamin D2 were also studied. The rate of singlet oxygen formation by 15 ppm riboflavin was 1.78 umole oxygen/mL headspace-hour. The reaction rate constant of vitamin D2 with singlet oxygen was 2.2 times 107 M−1A s−1. The carotenoids minimized the oxidation of vitamin D2 by quenching singlet oxygen. The total quenching rate constants of retinol, retinyl acetate, jucoxanthin and ft-carotene were in the order of 1.22 times 108, 5.98 times 108, 1.78 times 109 and 5.00 times 109M−1. s−1 respectively, which suggests that as the number of double bonds of carotenoids increases, the quenching rate constant ofcarotenoid increases.
Test temperature and strain rate effects on the properties of a tungsten heavy alloy

Liquid phase sintered tungsten heavy alloy specimens with a 90W-7Ni-3Fe composition were tested for temperature and strain rate effects on mechanical behavior. Both fracture stress and strain were measured for samples tested at 20, 300, or 600 °C, with crosshead speeds ranging from 0.004 to 400 mmJs in an argon atmosphere. Fracture surface examinations showed a dramatic increase in tungsten cleavage as the ductility increased. The effect of an increasing strain rate is a slight strength increase with a concomitant ductility decrease. Alternatively, higher test temperatures degrade strength with a nonsystematic effect on ductility; maximum ductility occurs at 300 °C and a slow strain rate. Surface oxidation at 600 °C greatly degrades ductility. The results are mathematically modeled using classic strain rate dependent equations.
Competitive Turgor Maintenance in Tall Fescue

Economical, rapid methods are needed to identify drought-tolerant turfgrasses. Objectives of this study were to (i) examine water relations of three tall fescue (Festuca arundinacea Schreb.) selections, (ii) determine the relationship between these characteristics and recovery from water deficit under greenhouse conditions, and (iii) assess the feasibility of using a competitive soil moisture extraction technique to select tall fescue germplasm with superior drought tolerance(.)
Holographic nondiverging hollow beam.

A simple holographic technique is used to generate a nondiverging hollow beam, which is similar to a ${\mathit{J}}_{1}$ Bessel beam. The hollow beam is obtained from a Gaussian beam with a high conversion efficiency (greater than 50%). We describe briefly the merit of this hollow beam, which has potential applications in particle collimation.
An anterior/posterior communication compartment border in engrailed wing discs: Possible implications for Drosophila pattern formation

Abstract Our previous studies have suggested that all the known lineage compartment borders in the wing imaginal disc of Drosophila are coincident with boundaries of reduced gap junctional communication (communication compartment borders). Since engrailed discs have a disrupted anterior/posterior ( A P ) lineage border ( G. Morata and P. A. Lawrence, 1975 , Nature (London)255, 614–617), it was of great interest to determine if their A P communication restriction boundary is similarly disrupted. Examination of gap-junction-mediated exchange of small fluorescent molecules between cells in the engrailed wing disc revealed a boundary of restricted communication that appeared to be identical to the wild-type A P communication restriction boundary. This result suggests that lineage compartments are not required for the formation of A P communication restrictions. Furthermore, we suggest that perhaps communication compartments are the domains within which information is provided for specifying the formation of lineage compartments.
Structural characterization of a metal-based perfusion tracer: Copper(II) pyruvaldehyde bis (N4-methylthiosemicarbazone)

Copper(II) pyruvaldehyde bis(N4-methylthiosemicarbazone), Cu(PTSM), has been obtained as a dark red crystalline solid from EtOH-DMSO solvent mixture and structurally characterized by x-ray crystallography. The molecule possesses the expected pseudo-square planar N2S2 metal coordination sphere; however, the copper center also interacts through its axial coordination site with the sulfur atom of an adjacent Cu(PTSM) molecule in the crystal lattice. The structure of this compound is compared with the structures of other metal complexes that have been proposed in the nuclear medicine literature as perfusion tracers.
Validating automated speaking tests

This paper presents evidence that supports the valid use of scores from fully automatic tests of spoken language ability to indicate a person’s effectiveness in spoken communication. The paper reviews the constructs, scoring, and the concurrent validity evidence of ‘facility-in-L2’ tests, a family of automated spoken language tests in Spanish, Dutch, Arabic, and English. The facility-in-L2 tests are designed to measure receptive and productive language ability as test-takers engage in a succession of tasks with meaningful language. Concurrent validity studies indicate that scores from the automated tests are strongly correlated with the scores from oral proficiency interviews. In separate studies with learners from each of the four languages the automated tests predict scores from the live interview tests as well as those tests predict themselves in a test-retest protocol (r = 0.77 to 0.92). Although it might be assumed that the interactive nature of the oral interview elicits performances that manifest a...
Tests of reproductive isolation among species in the Fundulus notatus (Cyprinodontiformes: Fundulidae) species complex

We assessed prezygotic (probability of spawning) and postzygotic (hatching success) reproductive isolation among the three ecologically and morphologically similar species in the Fundulus notatus species complex. We employed a multi-generation breeding experiment to test the hypotheses that karyotypic differences, body size differences, or geographic isolation among populations will increase pre or postzygotic reproductive barriers. Overall, prezygotic barriers were strong and postzygotic barriers weak in crosses of non-hybrid heterospecifics (F1 hybrid crosses) while prezygotic barriers were weaker and postzygotic barriers stronger in crosses involving hybrid individuals (F2 hybrid crosses and backcrosses). Prezygotic barriers among the two smaller species (Fundulus notatus and F. euryzonus) broke down rapidly; first generation hybrids spawned (F2 hybrid crosses and backcrosses) as frequently as parental forms in intraspecific crosses. There was no increase in postzygotic barriers among species with cytogenetic differences. There were increased prezygotic, but not postzygotic, barriers among geographically isolated populations of one species. While pure males and females were just as likely to spawn with hybrids, some types of hybrid females suffered from increased sterility, but not inviability, over hybrid males. Female sterility was only seen in hybrids with a Fundulus euryzonus parent, while other female hybrids produced viable eggs.
A computational model of cell migration in response to biochemical diffusion

The Computational Sciences and Engineering Division of the Oak Ridge National Laboratory is partnering with the University of Tennessee Graduate School of Medicine to design a computational model describing various factors related to the development of intimal hyperplasia (IH) in response to arterial injury. This research focuses on modeling the chemotactic and haptotactic processes that stimulate vascular smooth muscle cell migration into the intima. A hybrid discrete-continuous mathematical model of cell migration in response to biochemical diffusion was developed in C++. Chemoattractant diffusion is modeled as a continuous partial differential equation, whereas migration of the cells is modeled as a series of discrete events. Results obtained from the discrete state model for cell migration agree with those obtained from Boyden chamber experiments.
Dose-Dependent Effect of Salicylates in a Moss, Funaria hygrometrica

Plant growth regulators now include more than the classic examples auxin, cytokinin, ethylene, and gibberellin, but little is known about the activity of these additional classes of molecules in nonvascular plants. The formation of buds by protonema of the moss Funaria hygrometrica is perhaps the best known and most fully characterized developmental system in the nonvascular plants. Examination of the effects of exogenously supplied salicylic acid and acetylsalicylate on this bioassay system shows that salicylates can regulate growth and development in mosses, producing a dose-dependent inhibition of bud formation. Other experiments show that this action is distinct from any direct effect on the well-known cytokinin stimulation of bud formation, occurs late in the process of bud formation, occurs prior to the stable commitment of nascent buds, and is not an effect on the outgrowth of young shoots. Because mosses are the sister clade to the vascular plants, these results suggest that the ability to perceive and transduce salicylate signals is an ancient feature of land plant physiology.