cssi/SciSciGPT-SciSciNet huggingface dataset:
Atomic scale movement of the voltage-sensing region in a potassium channel measured via spectroscopy

Voltage-gated ion channels are transmembrane proteins that are essential for nerve impulses and regulate ion flow across cell membranes in response to changes in membrane potential. They are made up of four homologous domains or subunits, each of which contains six transmembrane segments. Studies of potassium channels have shown that the second (S2) and fourth (S4) segments contain several charged residues, which sense changes in voltage and form part of the voltage sensor. Although these regions clearly undergo conformational changes in response to voltage, little is known about the nature of these changes because voltage-dependent distance changes have not been measured. Here we use lanthanide-based resonance energy transfer to measure distances between Shaker potassium channel subunits at specific residues. Voltage-dependent distance changes of up to 3.2 A were measured at several sites near the S4 segment. These movements directly correlated with electrical measurements of the voltage sensor, establishing the link between physical changes and electrical charge movement. Measured distance changes suggest that the region associated with the S4 segment undergoes a rotation and possible tilt, rather than a large transmembrane movement, in response to voltage. These results demonstrate the first in situ measurement of atomic scale movement in a trans-membrane protein.
Saturation throughput analysis of different backoff algorithms in IEEE802.11

We develop a new analytical model of the existing binary exponential backoff (BEB) algorithm in IEEE 802.11 wireless LAN and two different proposals, exponential increase exponential decrease (EIED) and exponential increase linear decrease (EILD) backoff algorithms. A one-dimensional Markov chain model is constructed for each algorithm and used to compare throughput under overload conditions. Our approach simplifies previous analyses of the BEB algorithm which used a 2-dimensional Markov chain model. The saturation throughput as well as average backoff window and probability of success for all three algorithms are calculated and compared in various types of traffic and network loads. Analytical results are compared to the simulation results. We found that EIED performs always better than BEB, while EILD provides improvement at higher loads. Additionally, we show that the infinite retransmission assumption provides a very tight upper bound on throughput for all schemes.
A Trajectory for Validating Computational Emulation Models of Organizations

Validation of complex simulation models is a challenging problem in computational organization theory research. In this paper, we describe a validation strategy suitable for emulation simulation systems, and show how a comprehensive validation consists of a sequence of steps that evaluate different aspects of a computational organizational simulation model. We demonstrate how this strategy can be applied to the evaluation of the Virtual Team Alliance (VTA), an emulation simulation system designed to guide managers charged with organizational change. VTA required a “trajectory” of successive validation experiments, before managers where willing to follow the recommendations of VTA. Ultimately, we believe this validation approach can be applied to a wide range of different simulation systems, and will make identification of the strengths and weaknesses of organizational simulations easier.
MPEP Reduces Seizure Severity in Fmr-1 KO mice over Expressing Human Aβ

Metabotropic glutamate receptor 5 (mGluR(5)) regulates the translation of amyloid precursor protein (APP) mRNA. Under resting conditions, mRNA is bound to and translationally repressed by the fragile X mental retardation protein (FMRP). Upon group 1 mGluR activation, FMRP dissociates from the mRNA and translation ensues. APP levels are elevated in the dendrites of primary neuronal cultures as well as in synaptoneurosomes (SN) prepared from embryonic and juvenile fmr-1 knockout (KO) mice, respectively. In order to study the effects of APP and its proteolytic product Abeta on Fragile X syndrome (FXS) phenotypes, we created a novel mouse model (FRAXAD) that over-expresses human APPSwe/Abeta in an fmr-1 KO background. Herein, we assess (1) human APP(Swe) and Abeta levels as a function of age in FRAXAD mice, and (2) seizure susceptibility to pentylenetetrazol (PTZ) after mGluR(5) blockade. PTZ-induced seizure severity is decreased in FRAXAD mice pre-treated with the mGluR(5) antagonist MPEP. These data suggest that Abeta contributes to seizure incidence and may be an appropriate therapeutic target to lessen seizure pathology in FXS, Alzheimer's disease (AD) and Down syndrome (DS) patients.
Soil inorganic carbon sequestration as a result of cultivation in the mollisols

Soil inorganic carbon stock and its response to land use in grassland ecosystems are poorly understood. A detailed examination of soil organic and inorganic carbon distribution at depth in Mollisols of the U.S. Northern Great Plains and the Russian Chernozem shows that cultivation of these soils decreased soil organic stock and increased soil inorganic carbon stock. The global significance of these results is that one of the most fertile and productive agricultural soils in the world that was initially native grasslands incorporated massive amounts of organic matter into the soil during cultivation. This dramatic event (going from equilibrium native grassland state to being plowed) caused a loss of organic carbon, and our analysis indicates that there may have been a corresponding gain of soil inorganic carbon in fertile calcium rich soils in the temperate grassland ecosystem. Mollisols may be a significant sink of inorganic carbon through pedogenic carbonate formation, which may partially offset carbon loss from soil organic matter decomposition.
Radio Aurora Explorer: Mission science and radar system

[1] The Radio Aurora Explorer (RAX) satellite is the first of several satellites funded under the NSF CubeSat-based Space Weather and Atmospheric Research Program. RAX is a ground-to-space bi-static radar remote sensing experiment designed to measure and understand the causes of meter-scale ionospheric irregularities. Also known as field-aligned irregularities (FAI), such non-thermal, coherent fluctuations of electron density occur in response to strong ionospheric flows or plasma density gradients during geomagnetic disturbances and are considered a space weather concern due to disruption to communication and navigation signals. The RAX CubeSat was launched in November 2010 and conducted a single experiment in coordination with the Poker Flat Incoherent Scatter Radar. Due to geophysical inactivity, e.g., lack of strong ionospheric electric fields and low ionospheric densities, no FAI were expected or observed. However, the radar receiver payload operation was successfully demonstrated, including the capability to sense signals as low as −110 dBm, the capability of transmitter–receiver synchronization and accurate ranging, processing of 1.2 GB of raw radar data on board in less than 1 hour, and the downlink of the science results within three–four passes. Analysis of the payload data shows that the noise level is sufficiently low. Although the interference level is a concern, it does not appear to significantly limit the measurements. Toward the end of December 2010, the solar power system gradually degraded and the mission terminated in early February 2011 after prolonged loss of contact with the satellite. Meanwhile, RAX II was launched in October 2011 to a polar orbit. This paper describes the RAX science and radar system and presents the results from the first experiment conducted.
Forecasting errors in student media multitasking during homework completion

Media multitasking during homework completion has reached epidemic proportions in the modern educational environment. There is a crucial need to resolve the paradox of why students engage in these behaviors, even though they are linked to self-control and performance decrements. We evaluate the proposition that student media multitasking decisions are made in the context of inaccurate forecasts regarding the influence of these behaviors on affect, self-control, and performance. After providing forecasts to estimate the effects of media availability and media removal on these outcomes, sixty college students (N?=?60) were randomly assigned to alternative media availability conditions as they completed an actual homework assignment during an in-lab session. Students predicted media use to result in lower negative affect and diminished self-control. The direction of these forecasts was accurate, with media availability resulting in decreased negative affect and diminished self-control during the homework session. Nevertheless, students exhibited moderate to large forecasting errors in predicting the magnitude of these effects. Although no evidence was attained to demonstrate forecasting errors when predicting homework performance, exploratory analyses suggested the presence of individual differences in the nature of these predictions, with 53.3% of participants predicting a performance decrement, 23.3% of participants predicting no difference, and 23.4% of participants predicting a performance gain under conditions of media availability. We discuss the implications of these findings for students and educators. Student expectations and experiences when using media during homework were compared.Students were randomly assigned to work on homework with or without media available.Students predicted media use to yield reduced negative affect and self-control.The nature of students' expectations was accurate, but the effect magnitude was not.Students exhibited moderate to large affective and self-control forecasting errors.
Time-Delayed Broadcasting for Defeating Inside Jammers

We address the problem of jamming-resistant broadcast communications under an internal threat model . We propose a time-delayed broadcast scheme (TDBS), which implements the broadcast operation as a series of unicast transmissions distributed in frequency and time. TDBS does not rely on commonly shared secrets, or the existence of jamming-immune control channels for coordinating broadcasts. Instead, each node follows a unique pseudo-noise (PN) frequency hopping sequence. Contrary to conventional PN sequences designed for multi-access systems, the PN sequences in TDBS exhibit correlation to enable broadcast. Moreover, they are designed to limit the information leakage due to the exposure of a subset of sequences by compromised nodes. We map the problem of constructing such PN sequences to the 1-factorization problem for complete graphs. We further accommodate dynamic broadcast groups by mapping the problem of updating the assigned PN sequences to the problem of constructing rainbow paths in proper edge-colored graphs.
Mitral valve repair versus replacement

Degenerative, ischemic, rheumatic and infectious (endocarditis) processes are responsible for mitral valve disease in adults. Mitral valve repair has been widely regarded as the optimal surgical procedure to treat mitral valve dysfunction of all etiologies. The supporting evidence for repair over replacement is strongest in degenerative mitral regurgitation. The aim of the present review is to summarize the data in each category of mitral insufficiency and to provide recommendations based upon this data.
Anesthetic Management of Patients Undergoing Unilateral Video-Assisted Lung Reduction for Treatment of End-Stage Emphysema

Objectives: Nonanatomic resection of peripheral areas of lung is being performed via sternotomy for the treatment of end-stage emphysema. Recent technologic advances have allowed the resection of lung tissue using video-assisted thoracic surgery (VATS) techniques. The study was performed to document the physiologic changes that occur during unilateral VATS lung reduction in hopes of determining appropriate monitoring and intraoperative management strategies. Design: Prospective trial of unilateral VATS lung reduction. Setting: Tertiary care university hospital. Participants: Twenty patients with end-stage emphysema. Interventions: Participants underwent unilateral VATS lung reduction. Measurements and Main Results: Invasive hemodynamic monitoring was performed using radial and pulmonary artery catheters. Hemodynamic and respiratory gas exchange data were collected at four intraoperative points: (1) supine, two-lung ventilation; (2) lateral decubitus, two-lung ventilation; (3) lateral decubitus, one-lung ventilation, and (4) end of surgery, supine, two-lung ventilation. Data were compared with that collected at the first point. Patients tolerated lengthy surgical procedures and remained hemodynamically stable with no episodes of hypoxemia requiring treatment. Extubation was tolerated by 19 of 20 patients at the conclusion of surgery without further requirement of mechanical ventilation. Conclusions: VATS lung reduction under general anesthesia with one-lung ventilation is well tolerated. Permissive hypercapnia was well tolerated by all patients. Early extubation can be routinely accomplished in these patients.
Piezoresistive Properties of ITO Strain Sensors Prepared with Controlled Nanoporosity

A ceramic strain gage based on reactively sputtered indium-tinoxide ~ITO! thin films is being developed to monitor the structural integrity of components employed in aerospace propulsion systems operating at temperatures in excess of 1500°C. The hightemperature stability and piezoresistive properties depend to a large extent on the thickness of the active ITO strain elements comprising these ceramic strain gages. Scanning electron microscopy of the thick ITO sensors revealed a partially sintered microstructure consisting of a contiguous network of submicrometer ITO particles with well-defined necks and isolated nanoporosity. It appeared that densification of the ITO particles was retarded during high-temperature exposure with nitrogen playing a key role in stabilizing the nanoporosity. Based on these preliminary results, ITO strain sensors were also prepared by reactive sputtering in various nitrogen/oxygen/argon partial pressures to incorporate more nitrogen into the films. Under these conditions, sintering and densification of the ITO particles containing these nitrogen-rich grain boundaries was retarded and a contiguous network of nanosized ITO particles was established. The influence of nitrogen in the sputtered and annealed ITO films on the microstructure and the high-temperature piezoresistive properties was investigated, and the results are presented in this paper. As the operating temperature of gas turbine engines is increased and new materials are developed to meet these new challenges, there is a need to assess the structural behavior of components in these harsh environments, so that structural models can be validated and newly developed materials can be monitored during actual engine operation. Thin film sensors are ideally suited to make measurements of operational turbine conditions since they have negligible mass and thus, minimal impact on vibration patterns. They are nonintrusive in that the gage thickness is considerably less than the gas-phase boundary layer thickness and thus the gas flow path through the engine will not be adversely affected by these sensors. Not only are these sensors ideally suited for in situ strain measurement where high gas velocities are encountered, but these ceramic strain gages have excellent adhesion and similar thermal expansion coefficients to most oxides used for electrical isolation. 1-8 In addition, ceramic sensors are refractory, nonintrusive, and robust enough to withstand the high g loading associated with rotating components. For these reasons, ceramic strain gages based on alloys of indiumtin oxide ~ITO! were developed to monitor both the static and dynamic strain of components employed in advanced propulsion systems and active control surfaces. 9-11
One approach to musical intelligence

The author began Experiments in Musical Intelligence in 1981 as the result of a composer's block (D. Cope, 1991; 1996). His initial plan involved creating a computer program that would have a sense of his overall musical style. It would track the ideas of a current work such that at any given point the author could request a next note, next measure, next 10 measures, and so on. The author hoped that this new music would not just be interesting but relevant to his style and current work. Having very little cognitive information about his style, however, the author began creating computer programs that composed complete works in the styles of classical composers, about which he knew something more concrete.
Influence of sodium dodecyl sulfate on the physicochemical properties of whey protein-stabilized emulsions

Abstract The influence of sodium dodecyl sulfate (SDS) on the flocculation of droplets in 20 wt.% soybean oil-in-water emulsions stabilized by whey protein isolate (WPI) was investigated by light scattering, rheology and creaming measurements. The SDS concentrations used were low enough to prevent depletion flocculation by surfactant micelles and extensive protein displacement. In the absence of SDS, emulsions were prone to droplet flocculation near the isoelectric point of the proteins (4
Synthesis and characterization of compounds of di- and tributyltin chloride with adenine and guanine mononucleotides

Abstract Compounds have been synthesized between Bu 2 SnCl 2 or Bu 3 SnCl (Bu = n -C 4 H 9 ) and the nucleoside monophosphates adenosine 5′-monophosphate (5′-AMP), and guanosine 5′-monophosphate (5′-GMP), and their 3′–5′ cyclic analogs. The stoichiometry of the compounds of 5′-AMP and 5′-GMP with Bu 3 SnCl was 1:2 while that with Bu 2 SnCl 2 was 1:1. Only 1:1 compounds were obtained with the 3′–5′ cyclic nucleotides. The compounds were characterized by 1 H , 13 C , and 31 P NMR in DMSO and solid state IR spectroscopy, and to some extent, mass spectrometry. (Bu 3 Sn) 2 (5′-AMP) and (Bu 3 Sn) 2 (5′-GMP) appear to be monomeric with one Bu 3 Sn moiety bonded to the phosphate and the other one bonded to the 3′-oxygen of the ribose. However, a dimeric or small polymeric structure is possible. Bu 2 Sn(5′-AMP) and Bu 2 Sn(5′-GMP) are polymeric and differ in that in the latter compound the two butyl groups are in different environments while in the former compound both butyl groups are the same. For all of the Bu 3 Sn compounds, 31 P NMR chemical shifts indicate that tin is bonded to the phosphate group, but probably not chelated by it. A much larger 31 P upfield shift in (Bu 3 Sn) 2 (5′-GMP) is an indication of phosphate chelation. Structures are proposed for some of the compounds. The ribose conformation in the Bu 3 Sn nucleotides is C2′- endo and C3′- endo in the Bu 2 Sn nucleotides.
Insulin resistance induced by high-fat feeding is only partially reversed by exercise training

Diets high in saturated fat and simple carbohydrate result in an insulin-resistant state, while training increases insulin sensitivity. Insulin resistance was induced by feeding a high-fat, high-sucrose (HFS) diet to 4-week-old female Sprague-Dawley rats. A control diet (low-fat, complex-carbohydrate) was fed to another group for comparison. During the 4-week dietary treatment, half of each group was trained by treadmill running (2 h day−1, 6 days week−1m 30 m min−1, 0% grade). At the end of this 4-week experimental period, hindquarter perfusions were performed at either basal (0) or maximal (100 nM) insulin concentrations to determine glucose uptake, glycogen synthesis, total glycogen content and the activity of several enzymes. Insulin (100 nM) significantly increased glucose uptake and glycogen synthesis in all four groups (CON-UN, CON-TR, HFS-UN, HFS-TR, where CON, UN and TR refer to control, untrained and trained respectively). HFS feeding significantly decresed (P<0.002) glucose uptake (μmol g−1 h−1) with maximal insulin stimulation, while training significantly increased uptake (P<0.01) at both insulin concentrations. Glycogen synthesis was also increased by training (P<0.05) at both insulin concentrations, but accounted for only 25–28% of the glucose uptake. Although training improved the insulin resistance caused by the HFS diet, glucose uptake in the HFS-TR group was still significantly lower than the CON-TR group. Changes in glycogen synthesis are not great enough to account for the decrease or increase in glucose uptake found in the HFS-fed or trained animals.
SU‐E‐I‐57: Comparison of CT Head Dose Estimates Using DLP vs. Monte‐Carlo Simulations

Purpose: Imaging centers are increasingly seeking means to track radiation dose from computed tomography(CT). Many of these methods are based on the dose‐length product (DLP) reported on image‐based dose sheets, such as RADIANCE, an open‐source dose extraction software. We compare dose estimates from RADIANCE to those computed by eXposure, a commercial product which computes organ doses using Monte‐Carlo simulations. Methods: We review dose estimates for 1936 single‐phase, unenhanced head CT examinations performed in 2010 at our institution. The estimated whole‐body effective dose (ED) is derived from the total study DLP by multiplying the ICRP 60‐based k factor of 0.0021. For the same set of studies, ED is derived from the organ doses computed via Monte‐Carlo simulations using MIRD Adult and Age 15 phantom, average scanner model and ICRP 60 tissue weighting factors. ED estimates from both methods are compared. Results: The average ED derived from total DLP is 1.84 +/− 0.44 mSv, while the average ED derived from the organ doses is 2.01 +/− 0.3 mSv. ED estimates derived from the organ doses were 1.91 +/− 0.28 mSv for male patients and 2.11 +/− 0.29 mSv for female patients. According to the literature, adult female heads are 10% smaller on average than adult male heads. We hypothesize that the 11% higher ED estimate in the female patients reflects this head size differential between genders. A common adult head phantom is used for head CT acquisitions, and higher dose estimates in adult females may reflect a longer‐than‐necessary scan length. Conclusions: Estimating whole‐body effective dose using DLP is practical in the current clinical setting. For head CT exams, DLP‐based ED estimates appear concordant with organ dose‐based estimates. The data additionally suggests that dose savings may be achieved by optimizing scan length and mA for female patients.
Cycling in the Newton-Raphson algorithm

Summary To better understand the Newton‐Raphson algorithm more attention should be given to cases of non‐convergence, in particular to cases that lead to cycling iterates. The values of cycling iterates have been shown to be crucial to separating regions of convergence and divergence. This paper summarizes what has been written about cycling iterates and provides further examples of the Newton‐Raphson algorithm cycling when being used to solve for the zeroes of f(z). The examples include families of functions for which an initial value can be selected to initiate a cycle of any given length preceded by any given number of non‐cycling values and families of functions for which the cycle length is fixed and does not depend on the initial value. In each example, the regions of convergence and divergence are also delineated.
Stability of line-length estimates using the method of absolute magnitude estimation.

Absolute magnitude estimates of line length were made by two groups of nine subjects each. One group was tested and then retested at an intersession interval of 1 year and the other, at an intersession interval of 2 years. High temporal stability was observed in both groups in both the slope values, individual and group, of the power functions and in the numerical responses themselves.
Ultrastructure of the hypodermis during cuticle formation in the third molt of the nematode Nippostrongylus brasiliensis.

The fine structure of the hypodermis of Nippostrongylus brasiliensis, a parasitic nematode of the rat, was studied in free-living third-stage filariform (infective) larvae, and in parasitic forms undergoing the third molt. In filariform larvae the hypodermis displayed a comparatively poorly developed RER, and few Golgi complexes, mitochondria, and vesicles. Nuclei contained large amounts of heterochromatin and no nucleoli. After worms reached the lungs and the third molt began, the RER, Golgi complexes, mitochondria, multivesicular bodies, and coated vesicles greatly increased in amounts. Nuclei displayed less heterochromatin and contained prominent nucleoli. These morphological changes were associated with transition from the free-living to the parasitic mode in life. The results were correlated with the fact that the hypodermis in N. brasiliensis is actively synthesizing culticular collagen during the third molt.
Longitudinal Equilibrium Distributions of Ion Beams in Storage Rings with Internal Targets and Electron Cooling

A derivation of the model used to describe the longitudinal drag rate is presented along with analytic equations to describe various aspects of the longitudinal equilibrium of an ion beam in a storage ring with internal targets and electron cooling. The effects of transverse and longitudinal heating, cathode power supply ripple voltage, and the electron beam space charge depression are discussed.
Sports participation in an urban high school: Academic and psychologic correlates

Purpose: To study positive and negative correlates of sports participation in inner-city youth. Methods: We distributed anonymous questionnaires to 838 students in gym classes of an urban New York City High School. Forty five percent of students were male and 55% female, with mean age 16.0 years; 64% in grades 9-10, and 36% in grades 11-12; 63% black, 27% Hispanic, and 10% other; and 30% A/B students, 38% C students, and 32% D/F students. Results: All students reported some involvement in sports' 37% in 1-2 sports, 29% in 3--4 sports, 24% in ~ 5 sports; 20% played on local teams, and 12% on junior or senior varsity. Approximately one-third each reported no weekday sports participation (30%), 1-2 hours per day (34%), or ~ 3 hours (36%); and 34% reported no participation on weekends, 26% reported 1-2 hours per day, and 40% ~ 3 hours. Basketball, volleyball, baseball, and weight lifting were the most common sports. Enjoyment, recreation, and competition were the most commonly reported reasons for participation. While 86% of subjects considered school "extremely" or "very" important, 35% considered sports "extremely" or "very" important. However, many believed they would "definitely" or "probably" receive an athletic scholarship (52% males, 20% females). Males reported more (p < .05) weekday, weekend, and team participation, and greater expectations (p < .001) of a future in sports. Sports involvement was not statistically associated with academic performance or scores on either the Rosenberg Self-Esteem Scale or Depression Self Rating Scale. Steroid use, at least once, was reported by 11% of males and 4% of females.
Hemispheric asymmetries in visual search.

We conducted two visual search experiments, and found that target-detection accuracy and speed were better when the target was projected to the right hemisphere in the feature search condition and better when the target was projected to the left hemisphere in the feature-conjunction search condition. We propose that the highly efficient, so-called parallel search performance characteristic of feature search is enabled by a broadly distributed, global view of the visual field, and the right hemisphere is more efficient than the left in such global processing. On the other hand, the less-efficient performance characteristic of conjunction search (demonstrated by the set-size effect) involves serial shifts of focused attention, and the left hemisphere is more efficient than the right in such localised attentional processing. We suggest that hemispheric asymmetries observed in visual search are related to the attentional demands of the task, and that we adjust our attentional distribution to fit task difficul...
The potential for estrogens in preventing Alzheimer's disease and vascular dementia.

Estrogens are the best-studied class of drugs for potential use in the prevention of Alzheimer's disease (AD). These steroids have been shown to be potent neuroprotectants both in vitro and in vivo, and to exert effects that are consistent with their potential use in prevention of AD. These include the prevention of the processing of amyloid precursor protein (APP) into beta-amyloid (As), the reduction in tau hyperphosphorylation, and the elimination of catastrophic attempts at neuronal mitosis. Further, epidemiological data support the efficacy of early postmenopausal use of estrogens for the delay or prevention of AD. Collectively, this evidence supports the further development of estrogen-like compounds for prevention of AD. Several approaches to enhance brain specificity of estrogen action are now underway in an attempt to reduce the side effects of chronic estrogen therapy in AD.
Galactosaemia with fatal cerebral oedema.

Galactosaemia due to galactose-1-phosphate uridyltransferase deficiency (McKusick 23040) is associated, in the untreated patient, with gastrointestinal symptoms, hepatomegaly, hepatic dysfunction, cataracts, septicaemia and, eventually, mental retardation. Neonates with classical galactosaemia may also present with increased intracranial pressure, which is reported to resolve on a galactose-free diet (Huttenlocher et al., 1970; Belman et al., 1986). We describe a newborn with galactosaemia who died at 19 days of age with cerebral oedema unresponsive to medical management
Effects of dietary retinyl acetate on the promotion of hepatic enzyme-altered foci by polybrominated biphenyls in initiated rats

Abstract Vitamin A inhibits the development of some chemically-induced tumours. Since polybrominated biphenyls (PBBs) are hepatic tumour promoters and they affect vitamin A homeostasis in rats, we put forward the hypothesis that dietary levels of vitamin A would influence tumour promotion by PBBs. In the study described here, female Sprague-Dawley rats were initiated on day 1 by ip administration of diethylnitrosamine. On day 7 after initiation, the rats were fed a vitamin A-deficient basal diet that was supplemented with either 2000 IU (low-vitamin A) or 200,000 IU (high-vitamin A) retinyl acetate/kg feed. From day 30 after initiation until the end of the study, the following PBBs were added to the diets: Firemaster BP-6 (10 ppm), 2,4,5,2′,4′,5′-hexabromobiphenyl (10 ppm) or 3,4,5,3′,4′,5′-hexabromobiphenyl (1 ppm). The control animals received low- or high-vitamin A diets containing no PBBs. On day 180, the rats were necropsied, sections of various tissues were stained for histopathological examination and an evaluation of hepatic enzyme-altered foci was performed. Numbers of γ-glutamyl transpeptidase-positive foci/cm 3 liver and the mean volumes of these foci were lower in the high-vitamin A groups than those in the corresponding low-vitamin A groups, but these differences were not significant. The percentage of the liver volume occupied by foci was significantly greater in the low-vitamin A with 345-HBB group than in the corresponding high-vitamin A group. Thus, high dietary levels of vitamin A had some inhibitory effect on the promotion of hepatic-altered foci by 345-HBB in initiated rats.
A preliminary study of the chemical modification of cloud condensation nuclei in stratiform clouds at Whiteface Mountain, New York

Results are presented for pH, nitrate and sulfate ion content of cloud water collected at Whiteface Mountain in northern New York. Evidence exists for the production of sulfate in possibly one of the case studies and for nitrate production in all three of the case studies examined. The results are not entirely consistent with the hypothesis that chemical modification of cloud condensation nuclei (CCN) takes place in stratiform clouds. For only one case is CCN production evident and total aerosol number concentration is enhanced. The measured nitrate production cannot be accounted for by the soluble fraction of the CCN aerosol and may result from the absorption of interstitial HNO3(g). This might account for the change in cloud condensation nuclei, indicated by the results, when sulfate production was not evident. The CCN spectrum can also be altered by agglomeration of captured particles upon cloud droplet evaporation. It is not possible to separate the two mechanisms (chemical vs physical) at this time.
Watson’s nonparametric two-sample test

Watson (1962) introduced a distribution-free test of the null hypothesis that two samples come from the same population. The computed statistic, U , depends on the relative ranks of the observations in the two samples, and not on the starting point of the measurement scale. Thus, while it may also be used for data measured on a linear scale, the test is especially useful for data on a circle, for which conventional hypothesis testing is inappropriate. Common data from a circular scale of measurement are compass directions or clock times; parametric testing for such data is possible (see Batschelet, 1965, 1972; Mardia, 1972; Zar, 1974, 1976). Watson's nonparametric test is described in Batschelet (1965, pp. 35·36), Mardia (1972, pp. 201-203), and Zar (1974, pp. 324.326). A computer program has been developed that performs Watson's (1962) calculation of U , appro, priate for either nontied data or data tied within and/or between samples. The most extensive tables of critical values of U are in Zar (1974, pp.575-576). Stephens (1965) gives Pearson curve approximations for some large sample sizes. For large samples, a normal deviate may be calculated as:
Pathophysiology of Soman intoxication in primates

Abstract Adult baboons were monitored during intravenous infusion of Soman (1,2,2-trimethylpropyl ester, phosphonofluoridate). Three groups of animals were studied. Two groups were anesthetized with sodium pentobarbital (initial dose, 20 mg/kg), instrumented for measurement of systemic blood pressure (BP), pulmonary artery pressure, cardiac output (CO), ECG, ventilatory flow, translaryngeal pressure (P TL ), transdiaphragmatic pressure (P di ), transpulmonary pressure (P TP ), diaphragm EMG, and efferent phrenic nerve traffic (E ph ). One group received no Soman and served as controls. In the other group, Soman was infused over 10 min at doses of 13.1, 8.21, 4.92, or 3.3 μg/kg. The onset of intoxication occurred within 7–8 min (before the end of the 10-min infusion), manifested by muscular fasciculations, stridorous breathing, copious secretions, and atrioventricular arrhythmias. Mean BP decreased to 30 mm Hg by the combination of decreased CO and decreased vascular resistance. There was a dose-related response in the onset and duration of these effects. Apnea occurred in most animals and coincided with cessation of the E ph signal. Stimulation of the diaphragm via the phrenic nerve following apnea yielded P di values unchanged from baseline, indicating an intact neuromuscular apparatus. All animals required ventilatory support. Some surviving animals exhibited severe behavior changes. The third group of animals was studied without anesthesia. Instrumentation was performed 3 days before using a tether system for the measurement of BP, CO, and ECG, and an arterial line for blood withdrawal. Soman was infused over 10 min at a dose of 13.1 μg/kg. The onset of intoxication occurred within 2–3 min, manifested by hyperactivity, severe muscle fasciculations which simulated grand-mal convulsions, stridorous respiratory sounds, copious secretions, and cardiac arrhythmias. Apnea and severe lactic acid acidosis developed in all animals and all required ventilatory assistance. None recovered spontaneous ventilation at the end of 4 hr.
Evidence on the effects of hostile and friendly tender offers on employment

This paper provides evidence on the effects of successful tender offers on the number of target and acquiring firm employees. No significant change in combined employment is observed, on average, over the three-year period following offer completion. However, hostile tender offers completed between 1980 and 1984 are followed by an average 17.2% decline in employment. Net divestitures of operations over the period are responsible for some of the observed employment decrease; however, an estimated -12.2% change remains, on average, after adjusting for divestiture activity. Information contained in firm annual reports and in the Wall Street Journal indicates that the tender offers in the sample are often followed by considerable restructuring activity with respect to both target and acquiring firm operations. The findings suggest that acquiring firm managements may acquire new operations when the need to restructure their existing operations frees up resources, e.g. cash and/or managerial time and talent. The evidence also suggests that the corporate control market must be viewed as an integral part of the process by which US firms restructure to meet changing circumstances.
The structure of sperner k-families

Abstract If P is a partially ordered set, a k-family of P is a subset which contains no chains of length k + 1. This paper examines the structure of the set of k-families of P. An extension of Dilworth's theorem is obtained by relating the maximum size of a k-family to certain partitions of P into chains. A natural lattice ordering on k-families is defined and analyzed, and a number of strong intersection properties are obtained. Finally, the k-families of P are used to define a class of submodular set functions on P, which can be used to generalize a number of results in transversal theory.
An evaluation of retrofit engineering control interventions to reduce perchloroethylene exposures in commercial dry-cleaning shops

Real-time monitoring was used to evaluate the ability of engineering control devices retrofitted on two existing dry-cleaning machines to reduce worker exposures to perchloroethylene. In one dry-cleaning shop, a refrigerated condenser was installed on a machine that had a water-cooled condenser to reduce the air temperature, improve vapor recovery, and lower exposures. In a second shop, a carbon adsorber was retrofitted on a machine to adsorb residual perchloroethylene not collected by the existing refrigerated condenser to improve vapor recovery and reduce exposures. Both controls were successful at reducing the perchloroethylene exposures of the dry-cleaning machine operator. Real-time monitoring was performed to evaluate how the engineering controls affected exposures during loading and unloading the dry-cleaning machine, a task generally considered to account for the highest exposures. The real-time monitoring showed that dramatic reductions occurred in exposures during loading and unloading of the dry-cleaning machine due to the engineering controls. Peak operator exposures during loading and unloading were reduced by 60 percent in the shop that had a refrigerated condenser installed on the dry-cleaning machine and 92 percent in the shop that had a carbon adsorber installed. Although loading and unloading exposures were dramatically reduced, drops in full-shift time-weighted average (TWA) exposures were less dramatic. TWA exposures to perchloroethylene, as measured by conventional air sampling, showed smaller reductions in operator exposures of 28 percent or less. Differences between exposure results from real-time and conventional air sampling very likely resulted from other uncontrolled sources of exposure, differences in shop general ventilation before and after the control was installed, relatively small sample sizes, and experimental variability inherent in field research. Although there were some difficulties and complications with installation and maintenance of the engineering controls, this study showed that retrofitting engineering controls may be a feasible option for some dry-cleaning shop owners to reduce worker exposures to perchloroethylene. By installing retrofit controls, a dry-cleaning facility can reduce exposures, in some cases dramatically, and bring operators into compliance with the Occupational Safety and Health Administration (OSHA) peak exposure limit of 300 ppm. Retrofit engineering controls are also likely to enable many dry-cleaning workers to lower their overall personal TWA exposures to perchloroethylene.
Serum electrolytes and the electrocardiogram.

Abstract 1. 1. Variations in potassium and calcium appear to be chiefly, if not entirely, responsible for electrolyte effects on the electrocardiogram. 2. 2. These effects are mainly on the form and duration of the repolarization wave. 3. 3. In the absence of gross changes due to heart disease, digitalis, or quinidine, a reasonably accurate prediction of marked deficits or excesses of either calcium or potassium can be made from the effects these ions produce on the electrocardiogram. 4. 4. In the interpretation of the electrocardiogram it should be appreciated that, at least in the case of potassium, it may be the intracellular, rather than the serum, level that influences the repolarization wave. 5. 5. Recognizable electrocardiographic abnormalities are usually present at levels of serum calcium below 3.5 meq. per liter and above 6.0 meq. per liter and at levels of serum potassium below 3.0 meq. per liter and above 6.0 meq. per liter.
Uniformity, standardization and terminology: Our problems and progress

Abstract There is increasing interest, particularly among fertilizer company soil testing laboratories, to standardize soil testing laboratory procedures and methods of reporting and interpreting soil test results. A Task Force Committee on Soil Testing was formed in 1969 by the Fertilizer Institute to formulate standard methods of testing soils. In 1971, a new organization called “Council on Soil Testing and Plant Analysis”; will begin soliciting a membership. The Council's primary objective is “to promote uniform soil test and plant analysis methods, use, interpretation and terminology”; with both organizations working toward a common goal. Considerable progress should be made toward standardizing the soil testing and plant analysis techniques.
Genetic control of gastrulation in the mouse

In the past, understanding of the process of gastrulation in the mouse has primarily been based on morphological analyses. Recently, a number of molecules have been implicated in mesoderm induction and axis formation in Xenopus, and several of these exhibit unique patterns of expression during mouse gastrulation. These gene-expression data, together with fate mapping, ectopic expression experiments and mutational analysis, will now facilitate studies on the functional aspects of gastrulation in the mouse.
The strong perfect graph conjecture holds for diamonded odd cycle-free graphs

Abstract In this paper, we show that the strong perfect graph conjecture holds for a new class of graphs which we call diamonded odd cycle-free graphs. The class of diamonded odd cycle-free graphs contains the classes of threshold graphs and K 4 \ e -free graphs.
Intermolecular transalkylation of methylanilines

Abstract Solid-acids such as Cr 2 O 3 /Al 2 O 3 , SiO 2 /Al 2 O 3 and large port zeolites such as faujasites catalyze intermolecular transalkylation of methylanilines by an electrophilic mechanism. This contrasts to the intramolecular, 1,2-shift isomerization mechanism observed with the zeolite HZSM-5. Aniline and 2,4,6-trimethylaniline give p -toluidine and 2,6-dimethylaniline in the presence of silica—alumina catalysts. They produce o -toluidine and 2,4-dimethylaniline in the presence of metal oxides on alumina. 2,4- and 2,6-dimethylaniline equilibrate in the presence of excess 2,4,6-trimethylaniline, o - or p -toluidine. Aniline as the methyl acceptor interconverts o - and p -toluidine with little formation of the meta isomer. The three dimethylanilines with one meta -methyl (2,3- 2,5- and 3,4-) equilibrate if m -toluidine is the methyl acceptor. We have determined kinetic and thermodynamic parameters for some of these reactions.
A GENERALISED ANALYTICAL RELATIVE ORIENTATION PROCEDURE AND ITS APPLICATION TO APOLLO 14 CLOSE UP PHOTOGRAPHY OF THE LUNAR SURFACE

Close up photographs of the lunar surface obtained by the Apollo 14 astronauts presented unusual problems in relative orientation caused by essentially different directions of the camera axes. The problem was resolved by dividing each large unknown rotation into two parts, one of which was a large known part and the other was a small unknown part. The method succeeds when the unknown rotation elements can be initially estimated to about 10°.
Acupuncture & IVF poor responders: a cure?

Background and Significance: The utility of acupuncture in the treatment of infertility has been demonstrated in two controlled studies. The first study determined the effect of reducing the Pulsatility Index (PI) of the uterine artery on reproductive outcomes; the second study described a Pre/Post embryo transfer protocol that enhanced overall pregnancy rates (PR). There are no studies that have utilized both techniques.
A high-precision super beta operational amplifier

A monolithic thin-film operational amplifier employing fully-protected super-beta transistors will be discussed. Drifts are less than 1 uV/° C, with source impedances as high as 100 kΩ.
Intraoperative blood pressure. What patterns identify patients at risk for postoperative complications

While monitoring blood pressure is a routine part of intraoperative management, several methods have been proposed to characterize intraoperative hemodynamic patterns as predictors of postoperative complications. In this prospective study of a high-risk population of hypertensive and diabetic patients undergoing elective noncardiac surgery, one objective was to compare different approaches to the assessment of intraoperative hemodynamic patterns to identify those patterns most likely to be associated with postoperative complications. Twenty-one per cent of the 254 patients sustained cardiac or renal complications after operation. Patients with more than 1 hour of greater than or equal to 20-mmHg decreases in mean arterial pressure (MAP) or patients with less than 1 hour of greater than or equal to 20-mmHg decreases and more than 15 minutes of greater than or equal to 20-mmHg increases were at highest risk for postoperative complications. Together these two patterns had a 46% sensitivity rate and a 70% specificity rate in predicting postoperative complications. Using 20% change in intraoperative MAP produced results nearly identical to 20-mmHg changes. When the duration of 20-mmHg changes was accounted for, changes of a greater magnitude (e.g., 40 mmHg) were not significant independent predictors of complications. The use of the mean difference from preoperative MAP was misleading because patients who experienced both high and low MAPs tended to have nearly normal mean MAPs, but high complication rates. The absolute magnitude of intraoperative MAPs, regardless of the preoperative levels, also was evaluated. The overall mean intraoperative MAP was not a significant predictor of complications. Specific intraoperative MAPs (e.g., less than 70 mmHg and more than 120 mmHg) also were evaluated. While neither was a significant predictor, there was a trend for increased complications among patients whose MAPs decreased to less than 70 mmHg. Intraoperative blood pressure should be analyzed in relation to the patient's preoperative blood pressure. Prolonged changes of more than 20 mmHg or 20% in relation to preoperative levels were significantly related to complications.
Simplified Expressions for Obtaining Approximately Optimum System-Reliability Confidence Bounds from Exponential Subsystem Data

Abstract Expressions derived by Mann and Grubbs [9] for obtaining confidence bounds on series-system reliability from exponential subsystem Type-II censored life-test data are simplified. The simplification allows calculation of confidence bounds based on weighted averages of only the first and second powers of the inverses of “total time on test” for the various independent subsystems tested. These approximate well (within about a unit in the second significant figure) optimum (uniformly most accurate unbiased) confidence bounds obtained iteratively by computer techniques from results of Lentner and Buehler [5] and El Mawaziny [1].