cssi/SciSciGPT-SciSciNet huggingface dataset:
Effects of Tetanization on Transmitter Dynamics

SUMMARY This discussion has surveyed the phenomenon of posttetanic potentiation (PTP), has indicated studies concerned with basic intracellular mechanisms responsible for this process, and has discussed the presumed role of PTP in epilepsy in relation to the actions of some antiepileptic drugs. New work concerned with transmitter dynamics during repetitive stimulation has been presented. A method is described for estimating rates of transmitter release and replenishment in synapses in which the transmitter has not yet been identified, such as in the spinal monosynaptic pathway. The method employs the degree of discharge of postsynaptic cells as a measure of the amount of transmitter released by each presynaptic impulse. Test responses are measured at constant intervals after periods of tetanization, which drain the amount of available transmitter in the terminals. The calculated rates of release and replenishment of excitatory transmitter in the spinal monosynaptic pathway yield predictions concerning behavior of this pathway during and following repetitive stimulation that are in good conformity with experimental observations. The method is further validated by employing it to calculate rates of release and replenishment of transmitter (acetylcholine) in the superior cervical ganglion. The calculated rates are in good agreement with published data obtained from perfusion studies. RESUME Cette discussion passe en revue le phenomene de la potentiation post-tetanique ainsi que des etudes relatives aux mecanismes intracellulaires fondamentaux qui sont responsables de ce processus et elle examine le role presume de la potentiation post-tetanique dans ľepilepsie, en relation avec les effets de certains medicaments anti-epileptiques. De nouveaux travaux relatifs a la dynamique des mediateurs pendant des stimulations repetitives sont presentes. Une methode ďestimation des cadences de mise en liberiteďun mediateur et de sa reconstitution dans des synapses ou le mediateur n'a pas encore ete identifye, comme dans le trajet monosynaptique spinal, est decrite. Cette methode utilise le degre de decharge des cellules postsynaptiques comme mesure de la quantite de mediateur mise en liberite par chaque impulsion presynap-tique. Les reponsesau test sont mesurees a des intervalles constants apres des periodes de tetanisation qui drainent la quantite de mediateur disponible dans les terminaisons. Le calcul des cadences de mise en liberte et de reconstitution du mediateur excitateur dans le trajet monosynaptique spinal permet de faire des previsions au sujet du comportement de ce trajet pendant et apres des stimulations repetitives et ces previsions sont en bonne concordance avec les observations experimentales. Cette methode trouve encore une utilisation valable dans le calcul des cadences de mise en liberte et de reconstitution du mediateur (acetylcholine) dans le ganglion cervical superieur; les taux calcules de cette maniere sont en bonne concordance avec des donnees publicees qui avaient ete obtenues a la suite ďetudes de perfusion.
Midgut and salivary gland barriers to La Crosse virus dissemination in mosquitoes of the Aedes triseriatus group.

. Vector competence for La Crosse virus (LACV) was compared for four species in the Aedes (Protomacleaya) triseriatus group: Ae.triseriatus (Say), Ae.hendersoni Cockerel], Ae.zoosophus Dyar and Knab and Ae.brelandi Zavortink (Diptera: Culicidae). Rates of replication and dissemination of virus in the mosquito hosts were compared and rates of oral transmission of virus to suckling mice were determined. Barriers to virus dissemination which limited the ability of each species to transmit virus were identified. Ae.zoosophus displayed the highest vector competence for LACV. Both infection and transmission rates were high: 99% and 85% respectively; no significant barriers to LACV were found. Disseminated infection of Ae. triseriatus with LACV was controlled primarily be a midgut escape barrier. When virus was introduced directly into the haemocoel, transmission rates were significantly increased (37% v. 79%). Ae.hendersoni showed high susceptibility to LACV infection but a very low rate of oral transmission (7%). Ae.brelandi was also highly susceptible to infection by LACV and transmitted virus at an intermediate rate (27%). Modulation of vector competence in both Ae.hendersoni and Ae. brelandi resulted from a salivary gland escape barrier. As these four species of mosquitoes comprise a closely related monophyletic series, their differences of vector competence for LACV provide an excellent model for studying the genetic basis of the barriers involved.
β‐Si3N4Whiskers Embedded in Oxynitride Glasses: Interfacial Microstructure

Interfacial microstructures in βP-Si3N4(w)-Si-Al-Y-O-N-glass systems were investigated by systematically varying the nitrogen content and the Al:Y ratio of the glass matrix. High-resolution and analytical transmission electron microscopy (HREM and AEM) studies revealed that the interfacial microstructure is a function of the glass composition. No interfacial phases were formed in glasses with low Al:Y ratios and in glasses with high Al:Y ratios and low nitrogen content, whereas epitaxial growth of an interfacial layer (100–200 μm thick) on the βP-Si3N4(w) occurred in a glass matrix with high Al:Y ratio and high nitrogen content. The interfacial layer was identified to be a β'-SiAION phase. Interfaces containing the SiAION layer exhibited high debonding energy compared to Si3N4(w)–glass interfaces. HREM studies indicated that the lattice-mismatch strain in the SiAION layer was relieved by dislocation formation at the SiAION–Si3N4(w) interface. The difference in interfacial debonding energy was, hence, attributed to the local atomic structure and bonding between the glass-β-Si3N4 and the glass–β'-SiAION phases. This observation was clear evidence of the strong influence of glass chemistry on the interfacial debonding behavior by altering the interfacial microstructure.
Garrison dam power

One of several large federal power projects on the Missouri River, the Garrison Dam when completed will produce an average annual gross energy of 1,600,000,000 kilowatt-hours. A number of interesting and unusual features to be incorporated in the project are discussed.
Prophylactic Cranial Irradiation in the Treatment of Small-Cell Carcinoma of the Lung

Almost 20 years after PCI was first proposed for the treatment of SCLC, its use remains controversial. Improvements in systemic therapy, including dose intensification with autologous bone marrow transplantation, may improve the survival of patients with SCLC but may also increase the number at risk for CNS failure if PCI is not used. While numerous studies have been performed, few address in a uniform manner the issues of dose, toxicity, and patient selection. Until such trials are available, the following guidelines are suggested: (1) patients with limited-stage disease who have a CR to chemotherapy are the ones most likely to benefit from PCI; (2) the radiation dose should be 30 to 36 Gy, given in daily fractions of 2 Gy; and (3) chemotherapy should not be administered simultaneously with PCI.
Experimental flowloop investigations of gas hydrate formation in high water cut systems

Abstract As oil/gas subsea fields mature, the amount of water produced increases, which results in an increased risk of gas hydrate plug formation in the flowlines. It is important to understand the mechanism of gas hydrate plug formation in high water cut systems in order to manage gas hydrate risk. In this work, we performed an extensive series of gas hydrate formation and dissociation experiments in a 4-inch diameter flowloop at the ExxonMobil research facility at Friendswood, TX. The flowloop was instrumented for pressure, temperature, density, and differential pressure measurements. The effect of mixture velocity (1–2.5 m/s) and liquid loading (50–90 vol.%) on gas hydrate plug formation was studied for 100 vol.% water cut (no oil present) systems, with methane as the gas hydrate former. The pressure drop across the pump due to flow did not substantially increase until a certain concentration of gas hydrates, defined as ϕ transition , formed; this transition, as measured by the rapid increase in pressure drop, can be used as an indication for onset of hydrate plug formation. ϕ transition was found to be unaffected by liquid loading and the presence of salt (3.5 wt.% NaCl) in water, while it increased with increasing mixture velocity. A gas hydrate plugging mechanism for 100 vol.% water cut systems is proposed, which involves a transition from homogeneous to heterogeneous suspensions of gas hydrate particles in water. We hypothesize that the large pressure drop observed after ϕ transition results from the formation of a gas hydrate bed and wall deposit. A correlation between ϕ transition and the mixture velocity is presented, this correlation allows the prediction of an onset of hydrate plug formation based on the fluids mixture velocity.
Acute and subacute rehabilitation for stroke: A comparison

Subacute rehabilitation, a recent innovation, is a less intense form of traditional inpatient rehabilitation. This study is a retrospective comparison of stroke treatment in a comprehensive inpatient service (acute rehabilitation) and subacute rehabilitation in a skilled nursing facility. Consecutive records during 1990 and 1991 resulted in 331 patients at the acute level and 97 at the subacute. Analysis of patient characteristics found few major differences between the two populations. Scrutiny of billing records found that acute program patients had twice as much treatment during a stay, twice the daily treatment hours, and twice the average charge per day. Acute rehabilitation patients showed substantially greater gains in functional impairment measures (FIM), but the proportion of patients discharged to the community varied little. Cost-effectiveness analysis found that the charge per successful discharge was more than double for acute rehabilitation. The charge per one point of FIM gain also was substantially higher. Although subacute rehabilitation was found to be more cost-effective than acute, additional research is needed to establish policies regarding rehabilitation services.
A study of premature infants fed cold formulas

The desirability of feeding infants with formulas warmed to the body temperature has been investigated in premature infants by controlled observations in which warmed formulas were compared with those given directly on removal from a refrigerator. Comparisons of the response to warmed or cold feedings in premature infants showed no significant differences in sleep patterns, vocalization, motility, intake of food or fluid, weight gain, or the regurgitation of food. The body temperature taken after feeding was found to vary ±1.2° F. from the temperature before the feeding in both the cold and the warm formula groups. Within this range the variability was found to be somewhat greater in the cold formula group. The average postprandial temperature in the warm formula group was the same as the preprandial temperature; in the cold formula group it was decreased by 0.2° F. The experiences in this study fail to demonstrate that the traditional procedure of warming the feeding is in any way advantageous to the infant.
Impact of upgrade to cardiac resynchronization therapy on ventricular arrhythmia frequency in patients with implantable cardioverter-defibrillators.

Impact of Upgrade to Cardiac Resynchronization Therapy on Ventricular Arrhythmia Frequency in Patients With Implantable Cardioverter-DefibrillatorsCengiz Ermis, Ryan Seutter, Alan X. Zhu, Lauren C....
Durability performance of RC beams strengthened with epoxy injection and CFRP fabrics

Abstract Cracks in reinforced concrete (RC) should be repaired if they present the potential for durability related problems such as corrosion of reinforcing steel. One way to repair extensive cracks is the use of epoxy injection. Another repair technique to enhance shear or flexural strength in deficient RC members is the utilization of externally bonded carbon fiber reinforced polymer (CFRP) fabrics. The effect of environmental conditioning on crack injection with or without CFRP strengthening is of interest in this investigation. Test results showed that the crack injection provided an increase in initial stiffness for un-strengthened RC beams. An increase in initial stiffness and ultimate strength was achieved in CFRP strengthened RC beams. Surface roughness combined with crack injection significantly increased the flexural capacity of the specimens. Environmental conditioning significantly affected the bond performance of the epoxy injection. The presence of sustained load during environmental conditioning resulted in reduced section capacity and ductility.
Standardized Tests and Timed Curriculum-Based Assessments: A Comparison of Two Methods for Screening High-Risk Students

The present study compared two procedures used in identifying students as “at risk” for learning problems. One procedure was a standardized norm referenced assessment represented by the Metropolitan Readiness Test and the Metropolitan Achievement Test. The other test procedure was a variation of the Curriculum-Based Assessment (CBA), which used frequency to measure samples of academic behavior. Tests were administered to 144 kindergarten and 142 first-grade children. Although the two procedures were comparable in identifying high-risk students, they differed substantially in time, effort, and cost. These differences might be important for school districts with limited personnel and funds.
Lost in Cyberspace? Virtual Learning and Higher Education

This article examines the technological modernization of higher education since the mid-1980s with a view toward likely future directions and consequences. Four important questions are addressed: Does instructional computing uniquely add educational value to the learning process? Does CIT exacerbate socioeconomic inequalities? Can on-line education contribute to a revitalized public sphere in cyberspace? Are pressures for commercialization undermining the ethos of higher education? Social scientists should devote more attention to technologically shaped transformations in higher education.
Polymer-like structures of LiSCN, NaSCN, KSCN, RbSCN, and CsSCN complexes with an armed monoaza-15-crown-5 ether bearing a 3',5'-difluoro-4'-hydroxybenzyl group.

Structures of LiSCN, NaSCN, KSCN, RbSCN, and CsSCN complexes with 3‘,5‘-difluoro-4‘-hydroxybenzyl-armed monoaza-15-crown-5 ether (5) were investigated. The Li+ and Na+ complexes are (1:1)n polymer-like complexes bridged by hydrogen bonding. On the other hand, the K+, Rb+, and Cs+ complexes are polymer-like complexes bridged by the fluorine atoms of the side arms. The titration calorimetry and 19F NMR titration experiments suggest that one or both fluorine atoms along with the oxygen atom of the phenolic OH group coordinate to the alkali metal ions incorporated in the crown part of a second armed ligand to give polymer-like complexes in solution. The FAB-MS data indicated that larger alkali metal ions form more stable polymer-like complexes.
Prevention of pulmonary alveolar macrophage proliferation in newborn rabbits by hyperoxia.

As a test of the hypothesis that hyperoxia might hinder the growth of nascent lung macrophages, term newborn rabbits were treated with room air or increasing oxygen concentrations (40%, 80%, or ≥95%) for 96 hours after birth. After 24, 48, 72, and 96 hours of environmental exposure, pulmonary alveolar macrophage population kinetics were determined by three methods: (1) bronchoalveolar lavage cell yields, (2) thymidine incorporation by macrophages, and (3) assessment of macrophage cell division by mitotic indices. Newborn rabbits kept in room air or 40% inspired O 2 showed a steady increase of macrophages in lung lavage, but pups treated with 80% or ≥95% oxygen showed no rise of macrophage yield in lung washings after 96 hours of exposure (P 2 for 96 hours (P
Determinants of Airport Hubbing in the United States An Empirical Framework

This article examines the relationship between hub status of airports and their determinants. The factors governing the status of large hubs may not be the same as those determining the status of medium and small hubs. Using a binary logit model, the authors find that hubbing is more relevant in defining an airport than classifying a broader geographical area, for example, metropolitan statistical area. Results from their choice model defined over airport sample indicate that large hubs are qualitatively different than their medium- and small-hub counterparts. Thus, aviation activities captured in all hub airports as one continuous variable, for example, passenger enplanements, may not be appropriate for modeling purposes. An appropriate modeling may require grouping two or three broad categories of airports. Finally, their model determines an optimal size of the market that is presently served by hub airport. This finding has implications for both airport planning and future investment.
Bovine Milk Lipase. I. Isolation from Skimmilk

Abstract A procedure was developed for the isolation of milk lipase from skimmilk: Fresh skimmilk is coagulated with rennet, separating curd, and whey by centrifugation, with most of the lipase accompanying the curd. The lipase is solubilized from the curd by maceration in 1 m NaCl and centrifugation. The supernatant is half-saturated with (NH 4 ) 2 SO 4 , the precipitate collected, dissolved, dialyzed, and fractionated on DEAE-cellulose. The lipase-rich fraction is made to 30% (v/v) with dimethylformamide and then to half-saturation with (NH 4 ) 2 SO 4 . Under these conditions, the lipase remains soluble and is finally purified by filtration through Sephadex G-200. The homogeneity of the preparation was established by ultracentrifugation and starch gel electrophoresis. Specific activity was about 500 times that of skimmilk, with an over-all yield of 10%. The sedimentation coefficient was calculated to be 7.5 S, and the molecular weight about 210,000. With milk fat as substrate, pH optimum was 9.2 and temperature optimum 37C.
Scientific Discourse: Climate Change and Sea-Level Rise

AbstractSea-level rise (SLR) is one of the most damaging impacts of climate change. Rising sea levels lead to loss of coastal wetlands, coastal flooding, degradation of coastal ecosystems, and a general loss of quality of life. Due to its potential impacts on coastal management and on population health and safety, the impact of climate change on SLR has drawn significant attention in recent literature. SLR is associated with processes including glacial activity, ice-sheet melting, thermal expansion of sea water, hydrologic events such as increased or decreased land-based discharges, and local effects such as El Nino and La Nina, all of which are complexly linked to changes in global temperature. Unfortunately, many of these physical processes are not well understood in their relation to climate change, and the scientific knowledge required to represent them fully in predictive analysis is so complex that many current studies are shifting away from physical climate models to the application of empirical, s...
Modulation of natural killer susceptibility by indole alkaloid tumor promoter dihydroteleocidin B.

Abstract The indole alkaloid tumor promoter dihydroteleocidin B (DHTB) was shown to reduce the natural killer (NK) cell susceptibility of two established cell lines, U937 and K562. The decrease in NK susceptibility correlated with the induction of differentiation as documented by positive benzidine staining in the erythroleukemia K562 and by antibody-dependent cellular cytotoxicity effector function in the histiocytic lymphoma line U937, respectively. In contrast, DHTB treatment did not alter the NK sensitivity of the NK-resistant B-lymphoblastoid-cell Une RPMI 8866. Cold target inhibition experiments suggested that both effector-target recognition and post-recognition steps were affected by DHTB. These results lend further support to the notion that NK susceptibility of a given tumor cell may vary with the stage of differentiation.
Oxygen Radicals Elicit Paralysis and Collapse of Spinal Cord Neuron Growth Cones upon Exposure to Proinflammatory Cytokines

A persistent inflammatory and oxidative stress is a hallmark of most chronic CNS pathologies (Alzheimer's (ALS)) as well as the aging CNS orchestrated by the proinflammatory cytokines tumor necrosis factor alpha (TNFα) and interleukin-1 beta (IL-1β). Loss of the integrity and plasticity of neuronal morphology and connectivity comprises an early step in neuronal degeneration and ultimate decline of cognitive function. We examined in vitro whether TNFα or IL-1β impaired morphology and motility of growth cones in spinal cord neuron cultures. TNFα and IL-1β paralyzed growth cone motility and induced growth cone collapse in a dose-dependent manner reflected by complete attenuation of neurite outgrowth. Scavenging reactive oxygen species (ROS) or inhibiting NADPH oxidase activity rescued loss of neuronal motility and morphology. TNFα and IL-1β provoked rapid, NOX-mediated generation of ROS in advancing growth cones, which preceded paralysis of motility and collapse of morphology. Increases in ROS intermediates were accompanied by an aberrant, nonproductive reorganization of actin filaments. These findings suggest that NADPH oxidase serves as a pivotal source of oxidative stress in neurons and together with disruption of actin filament reorganization contributes to the progressive degeneration of neuronal morphology in the diseased or aging CNS.
A six year prospective controlled study of neonatal hypoglycemia

Between 1961–1964, thirty-nine newborns with transient neonatal hypoglycemia (Group I) were matched with 41 controls (Group II) on the basis of 9 weighted clinical criteria. On-going medical and social service care was provided and yearly EEG's, neurological and psychological examinations were done. Computer analysis indicated the infants to be well matched according to medical criteria as well as socio-economic background. The incidence of R.D.S., sepsis, hyperbilirubinemia, polycythemia and C.N.S. problems was similar in both groups. Nevertheless, the clinical course of Group I was more severe due to the manifestations of hypoglycemia. Recurrent hypoglycemia was seen in 4 children; there were no deaths in either group. The follow-up data on physical development indicate that Group I showed a significant lag in height and weight until 3 years of age, after which both groups were in the 25th percentile. Head size, significantly smaller at birth in Group I, remained below the 3rd percentile at age 6. An analysis of 214 EEG's failed to reveal any significant differences in abnormalities between the groups. Stanford-Binet scores at age 5 showed a mean IQ of 87 ± 4 in Group I (22) vs 94 ± 4 in Group II (20) children. At age 6, the mean IQ was 88 ± 4 in Group (14) and 96 ± 3 in Group II (18) children. These differences are not significant. W.I.S.C. scores at age 5 and 6 were similar in both groups. To date, the prompt and vigorous treatment of symptomatic neonatal hypoglycemia would appear to obviate marked differences in development.
Pedestrian scramble signal in Chinatown Neighborhood of Oakland, California: An evaluation

In 2002 the city of Oakland, California, implemented a scramble signal at the intersection of 8th and Webster Streets. Scrambles are traffic signals that give pedestrians exclusive access to an intersection by stopping vehicular traffic on all approaches, allowing pedestrians to cross diagonally or conventionally. The primary objective of this evaluation was to determine whether the installation of the pedestrian scramble at this location increased pedestrian safety. An analysis was conducted of pedestrian-vehicle conflicts and pedestrian violations occurring at the intersection before and after the signal was modified, and pedestrians were surveyed to ascertain public attitude toward and comprehension of the change. The modification to scramble signal phasing at the intersection resulted in a statistically significant decrease in conflicts between pedestrians and vehicles and a statistically significant increase in pedestrian violations. In general, pedestrians understood the change in the way the inters...
Carbohydrate restriction uniquely benefits metabolic syndrome and saturated fat metabolism

Metabolic syndrome (insulin resistance syndrome) represents a group of physiologic signs that indicate a predisposition to obesity, diabetes, and cardiovascular disease. Consistent with the idea that intolerance to carbohydrate is an underlying feature of metabolic syndrome, we present results showing that a low carbohydrate diet results in global improvement in traditional and emerging markers associated with metabolic syndrome. Control diets, restricted in fat, are shown to be less effective. Recent research results mandate a careful re-evaluation of the widespread belief that dietary saturated fat is harmful. Specifically, multiple recent reports find no association between dietary saturated fat intakes and cardiovascular disease (CVD). There is, however, a consistent pattern of increased risk for both CVD and type-2 diabetes associated with increased levels of saturated fatty acids (SFA) in circulating lipids. This raises the important question as to what contributes to increased levels of saturated fat in the blood? Whereas dietary intake of saturated fats and serum levels of SFA show virtually no correlation, an increased intake of carbohydrate is associated with higher levels of circulating SFA. This leads to the paradoxical conclusion that dietary saturated fat is not the problem; rather it’s the over-consumption of carbohydrate relative to the individual’s ability to metabolize glucose without resorting to de novo lipogenesis. From this perspective, insulin resistant states like metabolic syndrome and type-2 diabetes can be viewed as carbohydrate intolerance, in which a high carbohydrate intake translates to increased serum SFA and therefore increased risk. We all stand to benefit, both now and in the future, if a well-formulated low carbohydrate diet becomes an accepted option in promoting health across many sub-groups in our population.
Microphysical Observations in Summer MONEX Convective and Stratiform Clouds

Abstract Two-dimensional images of ice particles observed by a NOAA WP-3D research aircraft during the Summer Monsoon Experiment (SMONEX) are examined. These images were obtained in the temperature interval from −25° to 0°C. The particle structures and size distributions found in convective and stratiform clouds are compared. Branched crystals were located predominantly in stratiform clouds while column-shaped crystals were located commonly in both stratiform and convective clouds. Stratiform clouds, particularly those observed at temperature warmer than −7°C, had a much greater percentage concentration of large ice particles (>0.8 mm in diameter), and many of these ice particles were aggregates or branched crystals. The importance of aggregation and deposition above the melting level in the stratiform clouds is strongly suggested by these findings. Ice particle number concentrations measured with the cloud probe were often very high in convective clouds, with a maximum value of approximately 800 L−1. The...
Reproductive costs, condition and carotenoid‐based colour in natural populations of threespine stickleback (Gasterosteus aculeatus)

– Male threespine stickleback, Gasterosteus aculeatus, display an orange/red throat during the breeding season, which is carotenoid-based colour. We examined the relationship between energy-based costs of reproduction and colour in three lacustrine populations of threespine stickleback: two benthic (Willow and Big Beaver) and one limnetic (Lynne) ecotypes. In two lakes (Willow and Big Beaver) where benthic males defend nests against cannibalistic groups, males paid higher energy costs than in the third lake (Lynne) where cannibalistic groups are absent. We then examined colour variation within each population. Males from Lynne Lake did not change colour during the parental stage, whereas males from Willow and Big Beaver lakes became more intensely coloured. In addition, colour was typically independent of condition within stages. We propose that energy-based reproductive costs could explain some of the observed variation in colour by altering the payoffs associated with signalling effort during current versus future reproduction.
Andrea Palladio (1508–1580)

A brief description of Palladio’s life and works. The focus is on the evolution of his design methodology, including the growing importance of proportion to his approach. Selected mathematical details are cited in the endnotes, and the list of references includes many publications focused on the relationships between architecture and mathematics in Palladio’s designs.
Throughput-delay performance of packet-switching multiple-access channel with power capture

Abstract Power capture is the ability of a receiver to receive correctly the strongest of several messages that arrive during overlapping intervals. The presence of power capture in multiple-access packet switching channels introduces inequality in the access conditions to the channel when packets arrive at the receiver at different power levels. Two models for such channels under slotted ALOHA protocol with power capture are considered. In the first, a packet is transmitted at one of K possible power levels, and it is received correctly if no other packet is transmitted at the same or higher level. The second model is of a ground radio network where a received packet's power is inversely proportional to the distance it propagates. In this model, a packet transmitted from a distance r is received correctly if no other packet is transmitted from a distance smaller than a · r (a ⩾ 1). A technique developed by Lam (1974) is generalized to obtain the throughput-delay characteristics of the channel for both models. The effect of high power traffic on the lower power traffic is discussed, and it is shown that the ‘Sisyphus distance’ phenomenon predicted by Abramson (1977) for the case a = 1 in the second model does not exist in the more realistic case of a > 1.
self-injury among early adolescents

Abstract Background: Whereas much attention has been focused on adolescent risk behaviors such as substance use, much less has been devoted to self-injury in the general adolescent population. Purpose: This study had two purposes: (1) describe the prevalence of self-injury among early adolescents in the general middle school population, and (2) identify behaviors that are comorbid with self-injury. Methods: This study involved a secondary analysis of data gathered from 1,734 6th and 8th grade students using the middle school Youth Risk Behavior Survey. Results: The prevalence of self-injury among middle school youth in this study (N=1734) was 28.4%. Although the relationship between having ever tried self-injury and gender was significant, the effect size was small. Multilevel logistic regression identified six variables that were significantly related to (P < 0.01) having ever tried self-injury: peer self-injury, having ever tried inhalants, grade level, and belief in possibilities, abnormal eating behav...
Rationale for monitoring free drug levels

Recent developments in our knowledge of drug binding prompt the questions, in what circumstances are measurements of free levels necessary, desirable or not warranted? Free level monitoring should be considered for drugs for which the usefulness of plasma level monitoring has been established, drugs which are highly bound to plasma proteins, and which exhibit a variable free fraction. In terms of drug distribution, free drug concentration is independent of free fraction, while total concentration is a resultant of free concentration and free fraction. For drugs with a low extraction ratio, the total concentration at steady-state depends upon free fraction, but the free concentration is independent of free fraction. With high extraction ratio drugs, the free concentration is dependent upon free fraction but only after parenteral administration. There are numerous examples of drugs which are highly bound and exhibit large variations in free fraction. Free fraction may increase with drug concentration. Pathophysiological changes in the binding ligands, albumin and alpha 1-acid glycoprotein, as well as changes in the concentration of endogenous compounds which compete for binding sites, may also cause changes in free drug fraction. Binding interactions resulting from polytherapy may also result in a variable free fraction. Ultrafiltration devices now enable the convenient and accurate determination of free drug levels. Areas in which this should prove useful are investigations of concentration-effect relationships and clinical situations requiring intensive monitoring where binding changes are suspected.
Thermal properties of secondary organic aerosols

[1] Volume concentrations of steady-state secondary organic aerosol (SOA) were measured in several hydrocarbon/NOx irradiation experiments after passing through a constant temperature heated tube. Higher temperatures resulted in greater loss of particle volume. Negatives of the measured effective enthalpies of vaporization (ΔHvap,eff25–300) for SOA range from 11 to 44 kJ mol−1, and depend upon the reactant hydrocarbon (α-pinene, toluene, or 1,3,5-trimethylbenzene). Significant negative correlations between ΔHvap,eff25–300 and [NOx] are observed for SOA formed from α-pinene or toluene. The ΔHvap,eff25–300 of SOA formed in the photooxidation of toluene is similar to that generated by the nebulization of glyoxal, indicating that the oligomers formed by nebulizing glyoxal may represent a surrogate for the chemical mixture formed in toluene photooxidation. These laboratory measurements suggest that the thermodynamic behavior of SOA depends upon the reactant hydrocarbon mixture and NOx concentration.
Stochastic Ion Heating Due to the Parametric Ion-Acoustic Decay Instability

We report intense stochastic ion heating comparable to the electron heating, proportional to the energy density of the fluctuating electric fields of the ion-acoustic component of the decay instability. The ion-temperature rise time is comparable to, but longer than, the instability growth time, and many orders of magnitude shorter than collisional relaxation times.
Transient Response of Asymmetrical Carrier Systems

The transient properties of asymmetrical amplitude-modulated carrier systems are studied in the time domain. A vector integral method is given for the determination of system response to arbitrary modulation. Typical nonlinearity of the envelope transfer function is studied as a function of modulation depth. It is found that the time delay associated with a rising response to a step change is always less than the delay associated with a decreasing response to a similar change. Transient improvement as a consequence of detuning in asymmetrical systems appears to be accompanied by a decrease in signalto-noise ratio.
Large-Scale Digitizer System, Analog Converters

Analog to digital converter circuits that are based on the sharing of common resources, including those which are critical to the linearity and stability of the individual channels, are described. Simplicity of circuit composition is valued over other more costly approaches. These are intended to be applied in a large-scale processing and digitizing system for use with high-energy physics detectors such as drift-chambers or phototube-scintillator arrays. Signal distribution techniques are of paramount importance in maintaining adequate signal-to-noise ratio. Noise in both amplitude and time-jitter senses is held sufficiently low so that conversions with 10-bit charge resolution and 12-bit time resolution are achieved.
Electropolymerizable Terthiophene-Terminated Poly(aryl ether) Dendrimers with Naphthalene and Perylene Cores

We describe the synthesis and characterization of a new series of poly(aryl ether) dendrimers with both donor and acceptor moieties. By incorporating p-type terthiophene and n-type perylene and naphthalene diimides into one molecule, we have achieved a dual electrochromic material. These dendrimers were designed to act as electrochemically active precursor polymers, which bear the electroactive terthiophene group that can be cross-linked electrochemically to form conjugated polymer network (CPN) films. Characterization of the optical and redox properties shows that it is possible to incorporate donor and acceptor moieties in the same molecule with retention of doping properties. The films made by electrochemical polymerization are highly active in both the p- and n-doping processes and have been investigated by spectroelectrochemical methods.
Measurement of angular velocity in the perception of rotation

Humans are sensitive to the parameters of translational motion, namely, direction and speed. At the same time, people have special mechanisms to deal with more complex motions, such as rotations and expansions. One wonders whether people may also be sensitive to the parameters of these complex motions. Here, we report on a series of experiments that explore whether human subjects can use angular velocity to evaluate how fast a rotational motion is. In four experiments, subjects were required to perform a task of speed-of-rotation discrimination by comparing two annuli of different radii in a temporal 2AFC paradigm. Results showed that humans could rely on a sensitive measurement of angular velocity to perform this discrimination task. This was especially true when the quality of the rotational signal was high (given by the number of dots composing the annulus). When the signal quality decreased, a bias towards linear velocity of 5-80% appeared, suggesting the existence of separate mechanisms for angular and linear velocity. This bias was independent from the reference radius. Finally, we asked whether the measurement of angular velocity required a rigid rotation, that is, whether the visual system makes only one global estimate of angular velocity. For this purpose, a random-dot disk was built such that all the dots were rotating with the same tangential speed, irrespectively of radius. Results showed that subjects do not estimate a unique global angular velocity, but that they perceive a non-rigid disk, with angular velocity falling inversely proportionally with radius.
Plastic deformation in icosahedral Al--Pd--Mn alloys

The deformation characteristics of icosahedral Al[sub 70]Pd[sub 21.5]Mn[sub 8.5] have been investigated by high temperature creep experiments, and the resultant microstructures have been examined by transmission electron microscopy (TEM). From 730 to 780 [degree]C, microstructural analysis revealed that the deformation is controlled by dislocation glide, with an activation energy of 210[plus minus]30 kJ/mole and a stress exponent of 1.2[plus minus]0.2. From 780 to 810[degree] C, microstructures were characteristic of deformation controlled by dislocation glide and climb. The activation energy and stress exponent were determined to be 1700[plus minus]80 kJ/mol 2.9[plus minus]0.3, respectively. Hardness measurements also reflected an increase in dislocation density, as the hardness of the deformed samples was approximately 10% higher than the as-cast sample.
Most of the avian genome appears available for retroviral DNA integration.

Although retroviral integration requires specific viral DNA sequences, factors which govern the choice of a chromosomal target site within an infected celi are less clear. For example, certain chromosomal regions may be inaccessible to the viral integration machinery, while others may favor integration. A recent paper by Withers-Ward et al.(1) addresses this issue using a polymerase chain reaction-based assay capable of identifying single integration events within a large population of infected cells. Their results show that integration can occur into many different chromosomal regions, and that local DNA structure can influence the site of integration within a given region.
Development of circulating antigen assay for rapid detection of acute schistosomiasis.

Abstract A circulating antigen assay to detect acute schistosomiasis mansoni in experimentally infected mice has been developed. The competitive-inhibition enzyme-linked immunosorbent assay uses rabbit serum prepared against purified cercarial antigen. The assay detects a 100-worm infection as early as 1 week after exposure; circulating antigen levels in mouse serum exceeded 0·1 μg/ml. Preliminary characterisation of the cercarial antigen shows that it is a hydrophobic polypeptide of approximate molecular weight 41 000. A rapid and accurate diagnosis of acute schistosomiasis in travellers would facilitate appropriate chemotherapy before the onset of pathology. A circulating antigen assay would also be valuable for seroepidemiological studies in areas where the disease is endemic.
A Tomonaga-Schwinger-Dirac formulation for string theories

Abstract A Tomonaga-Schwinger-Dirac formulation of the first quantized free bosonic string theory is presented in which all the Virasoro operators have simple geometric meanings. In a corresponding second quantized version, the “chordal” gauge transformations on the free string field, which generate linearized gauge transformations of spacetime fields, become natural transformations in an extended loop space. The geometrical nature of these transformations may allow them to be more easily generalized to the nonlinear transformations of the interacting string field theory.
On the determinants of direct foreign investment: evidence from east and southeast Asia.

Abstract A model of derived demand for foreign capital by a multiple product monopolist is estimated for seven Asian countries. Direct foreign investment (DFI) inflows are estimated to be less elastic with respect to the costs of capital (including taxes) than to wages, and to be more elastic with respect to aggregate demand in export markets than domestic demand. The output deterrent effect of higher wages is estimated to outweigh any substitution toward greater capital intensity. The estimates also suggest that: DFI rises with greater costs within the investors' home countries; no similar effect occurs with respect to costs in rival host countries; and concerns for political stability have overlain economic determinants.
Repeated D1 dopamine receptor agonist administration prevents the development of both D1 and D2 striatal receptor supersensitivity following denervation.

Following 6-hydroxydopamine (6-OHDA) lesions of the nigrostriatal dopamine (DA) pathway, rat caudate-putamen (CPu) neurons are supersensitive to the inhibitory effects of both D1 and D2 dopamine (DA) receptor selective agonists. In addition, both the necessity of D1 receptor stimulation for D2 agonist-induced inhibition and the synergistic inhibitory effects of D1 and D2 agonists are abolished by denervation. The present study attempted to determine the relative roles of D1 and D2 DA receptors in the development of denervation supersensitivity to DA agonists and the "uncoupling" of functional interactions between the receptors following 6-OHDA lesions of the nigrostriatal DA pathway. Beginning on the day after an intraventricular 6-OHDA (or vehicle) injection, groups of rats received daily injections of either the selective D1 receptor agonist SKF 38393 (8.0 mg/kg, s.c.), the D2 agonist quinpirole (0.5 mg/kg, s.c.), or saline for 7 days. On the day following the last agonist injection, rats were anesthetized and prepared for extracellular single cell recording with iontophoretic drug administration. Daily administration of quinpirole selectively prevented the development of D2 receptor supersensitivity, whereas daily administration of SKF 38393 prevented the development of both D1 and D2 receptor supersensitivity. In addition, D1, but not D2, agonist treatment prevented the loss of synergistic inhibitory responses typically produced by 6-OHDA lesions. Behavioral observations revealed similar effects; daily injections of SKF 38393, but not quinpirole, prevented contralateral rotational responses to the mixed D1/D2 agonist apomorphine (1.0 mg/kg, s.c.) in rats with unilateral 6-OHDA lesions of the nigrostriatal pathway. After a 4-week withdrawal from repeated D1 agonist treatment, both supersensitive inhibitory responses of CPu neurons and contralateral rotations to apomorphine were evident, indicating that the preventative effects on DA receptor supersensitivity were not permanent. These findings indicate that continued agonist occupation of striatal D1 DA receptors following DA denervation not only prevents the development of D1 DA receptor supersensitivity but also exerts a similar regulation of D2 receptor sensitivity.
Exploring moral distress in pediatric oncology; a sample of registered practitioners

The aim of this research was to explore perceptions of doctors and nurses working in an English regional pediatric oncology unit, regarding their lived experiences and feelings relating to the concept of moral distress. This was undertaken to illuminate the understanding of team dynamics and the impact that the causes and repercussions of moral distress may have on that team. The qualitative methodology was influenced by the Heideggarian phenomenological approach and data analysis was undertaken using Colaizzi's (1978) phenomenological method for protocol analysis. Six main themes were identified expressing participants' experiences of morally distressing situations, with three warranting in depth exploration: "the importance of the decision-making processes," "conflict over right to treatment and withholding treatment," and "communication within the team." Moral distress does occur within pediatric oncology clinical settings and it has unavoidable triggers including emotional responses to difficult scenarios. The implications of this small study show benefits in sharing the decision-making process, thus enabling staff to recognize triggers more efficiently in clinical practice, enhancing communication through training and further research, collaborative education, de-briefing, and team meetings.
Effectiveness of a Social Skills Training Program with School Age Children: Transition to the Clinical Setting

Interventions that mobilize the parents to coach and reinforce their children's social skills have been shown to improve children's social functioning and decrease inappropriate social behaviors in the home and at school. However, few studies have examined whether these treatment outcomes can be successfully transferred from the research to the clinical setting. We examined the effectiveness of a 12-session manualized social skills intervention involving parent participation. As part of regular clinical practice, measures of children's social skills, self-control, and psychopathology were collected pre- and post-treatment. Findings suggest that parent ratings of children's social skills and self-control improved and aggressive behavior decreased.