cssi/SciSciGPT-SciSciNet huggingface dataset:
Modern Control Theory for Design of Autopilots for Bank-to-Turn Missiles

The state-space techniques of modern control theory are used to develop a methodology for the design of autopilots for bank-to-turn missiles. The methodology accommodates the gyroscopic and coriolis cross-coupling between the pitch and the yaw axes that result due to the high roll rates that can be present. The design uses the assumption that the roll rate is constant, but not zero, and results in an autopilot structure in which there are cross-couplings between the pitch and yaw channels that are dependent on the roll rate. The autopilot gains are also scheduled as functions of the dynamic pressure. A reduced-order extended Kalman filter, with fixed gains, is used to estimate the actuator states and the commanded acceleration. The performance of an autopilot designed by this methodology was evaluated in a six-degree of freedom simulation using the dynamics of a typical high-performance tactical missile. Excellent performance was obtained in teres of low miss distance and small side-slip.
Spontaneous laryngeal disease in the canine

This report describes the type and incidence of spontaneous laryngeal disease in the dog. Signs of laryngeal disease are similar to those in other species. Dogs are usually presented with inspiratory obstructive dyspnea or stridor, since earlier signs are often missed. Severe, congenital abnormalities may occur unrecognized due to neonatal death. Subtle anomalies are seldom presented. Congenital paralysis of the laryngeal musculature has been seen in the Bouvier des Flandres and the Siberian Husky. Laryngeal obstruction occurs commonly in brachycephalic dogs (Bulldog, Boxer, Boston Terrier, Pug, Pikingese). The forshortened nasal cavity and pharynx result in reduced airway space. The result is inspiratory obstruction varying from noisy respiration to severe obstruction with cyanosis and syncope. Everted laryngeal ventricles are most common in these dogs. Mild degrees of ventricular edema are common in small breed dogs with lower respiratory disease and in field-trial Beagles due to voice abuse. Traumatic injuries to the larynx and hyoid apparatus are not rare. Bite wounds from dog fights are the most common cause. Compression fractures are rare, but injuries associated with shearing stresses, due to being shcken by the neck cause airway obstruction. These types of injuries include avulsion of the aryepiglottic folds, longitudinal tearing of the epiglottis, arytenoid displacement, hyo-laryngeal separation, and laryngotracheal separation. Delayed signs of recurrent nerve damage are common in severe laryngotracheal injuries.
DC BREAKDOWN STRENGTHS OF SOME MULTICOMPONENT GAS MIXTURES IN CONCENTRIC CYLINDER GEOMETRIES

The results are reported of dc breakdown tests performed on mixtures of electron attaching gases from the group SF/sub 6/, c-C/sub 4/F/sub 8/, and 2-C/sub 4/F/sub 8/, and electron moderating gases from the group N/sub 2/, CHF/sub 3/, 1,1,1-C/sub 2/F/sub 3/H/sub 3/, in cylindrical-electrode geometries with different degrees of surface roughness, at total pressures of 0.1 and 0.44 MPa. Better electron moderating gases were sought. The binary mixture (c-C/sub 4/F/sub 8/ and 1,1,1-C/sub 2/F/sub 3/H/sub 3/) and a number of multicomponent mixtures involving SF/sub 6/, c-C/sub 4/F/sub 8/, 2-C/sub 4/F/sub 8/, CHF/sub 3/, N/sub 2/, and 1,1,1,-C/sub 2/F/sub 3/H/sub 3/ have shown improved properties (over SF/sub 6/) under the practical conditions of cylindrical geometry, rough surface, and high pressure.
Reaching Out to the Net Generation on Campus : Promoting the MSU Libraries in the Residence Halls

Abstract The tremendous expansion of online information sources has prompted academic librarians to increase their outreach to undergraduates of the “Net Generation” in an effort to more effectively promote their libraries' resources to these students. Such outreach programs involve identifying library resources that support the information-seeking behaviors of Net Generation undergraduates, as well as establishing collaborative relationships with the individuals and groups affiliated with these students. This article describes an outreach initiative conducted by the Reference Department at the Mississippi State University Libraries, in which the Department worked with staff in residence halls to target undergraduates living on campus.
Dynamic autonomous agent placement for target tracking based on target motion models

Tracking multiple navigating targets in a bounded region is a common problem that arises in many real-life applications, such as rescue operations, surveillance and reconnaissance. Placing a set of agents optimally to track targets, of interest is another problem associated with the tracking problem. This paper introduces a distributed stochastic approach to a well-defined agent placement problem, which can be shown to be NP-hard. First, a stochastic target motion model is introduced to enable agents to predict future target locations. Second, a model-based distributed algorithm is developed. Given the motion model, agents predict target location probabilities and compute their next best locations based on the predictions. The proposed approach involves coordination among mobile agents in order to achieve near-optimal global utilities. The approach has been evaluated through a set of simulation experiments. Simulation results reveal the superiority of the proposed model-based agent placement approach over existing approaches.
Negotiating the Life Narrative: A Dialogue with an African American Social Worker

This article explores two methodological issues that arise when researchers involve the women they study in the construction of life narratives. These issues are examined in the context of an interview-derived, life-narrative study of an African American social worker. First, the tension between presenting a neatly unified identity in a written text and acknowledging the contradictions within any person's life story are discussed from both the researcher's and participant's vantage point. The second issue addresses the dilemma that arises when the researcher and the research participant disagree about the meanings and interpretations garnered from the participant's life story. I contend that it is precisely at this moment that the research process has the potential to become a dialogue between theorists and that scholars can incorporate a woman's own theorizing about her life in the research. In concluding, several methodological suggestions are offered as broad guidelines for researchers planning a life-...
Regulation of Macromolecular Synthesis by Putrescine in a Conditional Escherichia coli Putrescine Auxotroph

Addition of putrescine to a slowly growing, polyamine-starved Escherichia coli K-12 mutant conditionally incapable of synthesizing putrescine causes the immediate stimulation of protein synthesis. After a period ranging from 60 to 105 min, ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) syntheses are also stimulated and rapid cellular division begins. Chloramphenicol blocks this rapid cellular division, although addition of the specific DNA synthesis inhibitor, nalidixic acid, has no effect on cell division. By sucrose gradient analysis and diethylaminoethyl-cellulose chromatography, the proteins initially made in response to putrescine appear to be composed of many classes, including membrane-bound proteins. However, the synthesis of ribosomal subunits is not altered during this period. A possible role for putrescine in either the stimulation of messenger RNA transcription or in translation is suggested.
A Survey of Microprocessor Architectures for Memory Management

This article presents an overview of current 16- and 32-bit microprocessor architectures that support memory management. The authors define the basic requirements for a processor to support memory management and introduce hierarchically organized memory. They describe several address translation schemes, such as paging, segmentation, and combined paging/segmentation and discuss their implementation in current microprocessors. They give special emphasis to the application of associative cache memory, and analyze and compare single-level and multi-level address mapping schemes. Futhermore, the article discusses the capabilities of current microprocessors to support virtual memory, which includes abilities to recognize an address fault, to abort the execution of the current instruction and save necessary information, and to restore the saved state and resume normal processing. The authors evaluate two methods to restart the interrupted instruction, instruction restart and instruction continuation, and discuss their implementation in current microprocessors. They also discuss protection and security issues, and evaluate two protection schemes, hierarchical and nonhierarchical.
NPT-IGBT-optimizing for manufacturability

High-voltage NPT-IGBTs (non-punchthrough IGBTs) offer reasonable on-state voltages, high short-circuit ruggedness, and minimal turn-off losses without lifetime killing. In addition, NPT-IGBTs have the potential to reduce fabrication costs as compared to conventional epitaxial IGBTs because they are fabricated on low cost bulk silicon substrates, while conventional IGBTs utilize thick, expensive epitaxial layers. The key to realizing this potential cost savings, however, is the development of a manufacturable thin-wafer back end process flow. This paper will discuss NPT-IGBT process optimization, aimed at increased manufacturability. Starting material specifications, backside process optimization, and thin-wafer manufacturability issues are addressed.
CFD study of compost waste heat for use in a hybrid solar tower

The goal of this research is to use Computational Fluid Dynamics (CFD) to numerically investigate the heat transfer associated with the waste heat released from using compost to assist the flow in a solar chimney. The novelty of the current research is the hybrid aspect of using a solar chimney in conjunction with compost waste heat to enhance the performance of the solar chimney. Additionally, the hybrid device will use photovoltaics stored on the roof of the solar chimney to generate electricity. Many CFD studies are available in the literature regarding the optimization of the solar chimney, which indicate that the power generation of the chimney is directly proportional to the height of the chimney, as well as the diameter of the base of the chimney. The new contribution of our present research will be in using CFD to quantify and match empirical data for the release of heat from a composting pile, which is the key piece of technology in converting the composting waste heat into usable renewable energy. Preliminary feasibility studies have been performed by the authors indicate the hybrid solar chimney concept to be viable, i.e. a 300 m tall tower will generate approximately 40 kW, which is in qualitative and quantitative agreement with other archived published studies.
Sc3N@C78 : Encapsulated cluster regiocontrol of adduct docking on an ellipsoidal metallofullerene sphere

The first N-tritylpyrrolidino derivatives of D3h (78:5) Sc3N@C78 were successfully synthesized and isolated. The addition sites for the two nearly equivalent kinetic monoadducts 1a and 1b are across two different 6,6 junction sites on the Sc3N@C78 cage that are offset from the horizontal plane defined by the Sc3N cluster. The adducts were characterized by NMR experiments, DFT calculations and X-ray crystallographic analysis of Sc3N@C78 derivative 1a. A unique finding of this study is the regiocontrol of adduct docking by the internal Sc3N cluster.
Effect of Water Movement on Ion Movement into the Xylem of Tomato Roots

11. HAGEN, C. E. AND H. T. HOPKINS. 1955. Ionic species in orthophosphate absorption by barley roots. Plant Physiol. 30: 193-99. 12. HAGEN, C. E., J. E. LEGGETT, AND P. C. JACKSON. 1957. The sites of orthophosphate uptake by barley roots. Proc. Natl. Acad. Sci. 43: 496-506. 13. HODGES, T. K. AND Y. VAADIA. 1964. Uptake and transport of radiochloride and tritiated water by various zones of onion roots of different salt status. Plant Physiol. 39: 104-8. 14. HODGES, T. K. AND Y. VAADIA. 1964. Chloride uptake and transport in roots of different salt status. Plant Physiol. 39: 109-14. 15. HOFSTEE, B. H. J. 1952. On the evaluation of the constants Vm and Km in enzyme reactions. Science 116: 329-31. 16. JACKSON, P. C. AND H. R. ADAMS. 1963. Cationanion balance during potassium and sodium absorption by barley roots. J. Gen. Physiol. 46: 369-86. 17. LEGGETT, J. E. 1961. Entry of phosphate into yeast cells. Plant Physiol. 36: 277-84. 18. LEGGETT, J. E. AND E. EPSTEIN. 1956. Kinetics of sulfate absorption by barley roots. Plant Physiol. 31: 222-26. 19. NOGGLE, J. C. AND M. F. FRIED. 1960. A kinetic analysis of phosphate absorption by excised roots by millet, barley, and alfalfa. Soil Sci. Soc. Am. Proc. 24: 33-35.
The non-productive entrepreneurial process

A large literature explores the importance of entrepreneurship as the catalyst of economic progress. In contrast, this paper argues that entrepreneurs are the driver of economic stagnation. We analyze the non-productive entrepreneurial process and discuss three channels through which non-productive activities have a multiplier effect culminating in economic decline and stagnation. Drawing on examples of non-productive entrepreneurship from both underdeveloped and developed countries, we provide insight into why economic stagnation persists in the former and why economic decline can occur in the latter.
Surface detail in computer models

Quantitative characterization of surface appearance is an important but difficult task. Surfaces of real world objects are detailed landscapes, with complex geometry and local optical properties. Surface appearance is strongly affected by the direction from which it is viewed and illuminated. Computational modeling of surface texture has potential uses in many applications including realistic rendering for computer graphics and robust recognition for computer vision. For recognition, the overall structure of the object is important, but fine-scale details can assist the recognition problem greatly. We develop models of surface texture and demonstrate their use in recognition tasks. We also describe a texture camera for capturing fine-scale surface details. Specifically, the texture camera measures reflectance and surface height variation using curved mirrors. We discuss why measurements and models of fine scale detail are important in modern industrial applications.
Properties of Supergranulation During the Solar Minima of Cycles 22/23 and 23/24

The solar minimum at the transition from cycle 23 to 24 was notable for its low level of activity and its extended duration. Among the various fields of study, the evolution of the solar convection zone may provide insight into the causes and consequences of this recent minimum. This study continues previous investigations of the characteristics of solar supergranulation, a convection component strongly linked to the structure of the magnetic field, namely the time-evolution of the global mean of supergranule cell size, determined from spectral analysis of MDI Dopplergrams from the two previous solar minima. Analyses of the global mean of supergranule sizes show a quasi-oscillatory nature to the evolution of this particular supergranule characteristic. Performing similar analyses on realistic, synthetic Doppler images show similar time-dependent characteristics. We conclude that the observed fluctuations are not observational artifacts, and that an underlying trend exists within the evolution of the supergranulation network.
Reduced photoreceptor damage after photodynamic therapy through blockade of nitric oxide synthase in a model of choroidal neovascularization.

PURPOSE. To investigate the role of nitric oxide synthase (NOS) in photoreceptor degeneration associated with photodynamic therapy (PDT) in a laser-induced model of choroidal neovascularization (CNV). METHODS. PDT was performed in monkey and Brown Norway rats with laser-induced CNV. L-NAME, a NOS inhibitor, or saline was injected intraperitoneally in rats with CNV. An NO donor, or saline, was injected intravitreously into normal rats. Photoreceptor apoptosis was evaluated by TUNEL and electron microscopy. NOS, ED-1, and cleaved-caspase-3 (c-casp-3) expression were determined by immunohistochemistry. CNV lesions were examined by fluorescence angiography and choroidal flat mount. RESULTS. TUNEL and electron microscopy showed photoreceptor apoptosis after PDT. In rats, there were significantly more TUNEL-positive cells in the photoreceptors 24 hours after PDT, whereas in the CNV lesions there were more TUNEL-positive cells 6 hours after PDT. C-casp-3 was detected in the CNV lesions but not in the photoreceptors after PDT. There was no difference in the numbers of ED-1-positive macrophages before and after PDT. However, inducible NOS (iNOS) was increased after PDT in macrophages. Intravitreous injection of the NO donor without PDT also induced substantial photoreceptor apoptosis. L-NAME-treated animals had significantly fewer TUNEL-positive cells in the photoreceptors than saline-treated animals after PDT (P < 0.05). There were no differences in CNV size and leakage between L-NAME- and saline-treated groups. CONCLUSIONS. iNOS expression in macrophages contributes to PDT-induced photoreceptor degeneration. NOS inhibition reduces PDT-induced photoreceptor degeneration without compromising the treatment effect of PDT in an experimental model of CNV.
Use of a discontinuous Percoll gradient technique for the separation of channel catfish, Ictalurus punctatus (Rafinesque), peripheral blood leucocytes

Abstract The use of a discontinuous density Percoll gradient in the separation of channel catfish peripheral blood leucocytes is described. The procedure yielded fractions enriched in monocytes and lymphocytes at the 1·060–1·065 g/ml interface, lymphocytes at the 1·065–1·070 g/ml interface, and neutrophils at the 1·070–1·080 g/ml interface. Cell purities among fractions ranged from 14·4–51·6% for monocytes, 61·4–72·8% for lymphocytes, and 60·4–79·2% for neutrophils. Factors influencing the outcome of the separation procedure include the use of pooled blood samples and calcium- magnesium-free salt solutions.
Structure, Dynamics, and Electrostatic Effects on Membrane Binding of Nod Peptides

A Sec14p-nodulin domain phosphatidylinositol transfer protein has been shown to polarize membrane growth of root hairs. To understand the mechanism of regulation, we have synthesized three peptides mimicking the sequence thought to be responsible for the targeted membrane binding containing single Cys substitutions. Binding of the peptides to model membranes was studied by spin-labeling EPR, ITC and DLS as a function of the bilayer lipid composition, with emphasis on the presence of phosphatidylinositol (PI) and brain PI(4,5)P2. For EPR studies, peptides were labeled with thiol-specific spin label (2,2,5,5-tetramethyl-2,5-dihydro-1H-pyrrol-3-yl)methyl methanesulfonothioate (MTSL) and membrane binding was characterized from changes in EPR spectra. Binding data were analyzed using a comprehensive model that includes description of electrostatic interaction by the Gouy-Chapman theory. Analysis of local polarity and accessibility of the EPR label for the bound form of the peptides was used to assess the location of bound peptides within model phospholipid bilayers. Substantial differences in binding behavior of these charged peptides were observed despite the similarity in sequences. Binding of the peptides did not induce liposome leakage or fusion. Unusual temperature dependent reversible effect of the peptides on liposome aggregation was observed and showed strong dependence upon membrane composition, especially the presence of PI(4,5)P2 lipids. Supported by NSF 0843632 to TIS.
Organic nitrogen exports from urban stormwater wetlands in North Carolina

Abstract Effluent organic nitrogen concentrations from seven constructed stormwater wetlands in North Carolina were examined to compare background organic nitrogen (ON) concentrations and the fraction of organic nitrogen relative to total nitrogen discharged. Seasonal influences on organic nitrogen concentrations were also examined. The median ON concentration from the stormwater wetlands was 0.78 mg l−1, and despite differences in wetland design and influent ON characteristics, outlet ON concentrations from all but one wetland were not significantly different. ON export from all stormwater wetlands was significantly less than untreated runoff entering the wetlands (p = 0.002). In addition, median organic:total nitrogen (ON:TN) ratios from stormwater wetlands (0.75) were significantly greater than from untreated urban runoff (0.66), comparing more closely to ON:TN ratios collected from a naturally occurring wetland and reported in the literature for natural landscapes. Seasonal differences in organic nitrogen concentrations were identified with significantly lower concentrations during the winter. Though stormwater wetlands will not (and perhaps should not be expected to) completely remove total nitrogen loads from runoff, these results suggest constructed wetlands can play a role in restoring the balance between organic and inorganic nitrogen forms closer to that of an undisturbed landscape. The presence of background organic nitrogen concentrations from stormwater wetlands similar to those from a naturally occurring wetland highlights the importance of choosing appropriate metrics (e.g., effluent concentrations) when assessing treatment performance.
The effect of track position on absenteeism

Absenteeism is one of the major problems facing America's schools. Absenteeism disrupts the learning environment, is related to lower levels of achievement, and is associated with problems of crime and delinquency. While previous research has identified many of the determinants of absenteeism, the role of a student's position in the tracking structure within a school has not been explored. The purpose of this paper is to explore this relationship. Ordinary least squares (OLS) regression results reveal that students who are in the lower tracks within the tracking structure in a school are more likely to be absent than other students and that Black and female students in low tracks are more adversely affected by the low-track environment that non-Black and male students. These results suggest that track position must be taken into consideration when dealing with the problem of absenteeism.
Laboratory Performance Appraisal

An important aspect of the principal investigator's job is to mentor students and postdocs and help them develop as scientists. In guiding my own lab members, I knew that it was important to give t...
The existence of core allocations in a one sector model of capital accumulation

Abstract The existence of core allocations in a one sector model of capital accumulation with heterogeneous households is demonstrated. The result follows as an application of Scarf's Theorem on the core of a balanced game.
Compositional reasoning of performance in component-based distributed systems

Rapid prototyping of distributed systems can be achieved by integrating commercial off-the-shelf (COTS) components. With components as the building blocks, it is important to predict the performance of the system based on the performance of individual components. In this paper, performance prediction of a system consisting of a small number of components is investigated under different inter-component communication patterns, and the number of threads provided by components. Based on the experimental results, it can be inferred that the proposed composition rules provide a reasonably accurate prediction of the performance of a system made out of these components.
Student and faculty perceptions of teaching effectiveness

Omnibus measures of teaching effectiveness can be viewed as weighted combinations of more narrowly defined traits describing the teaching process. Our study was designed to determine whether students and faculty weight such traits differently in forming their respective perceptions of effective teaching.
ARE LIBRARIES HOSTAGE TO RISING SERIALS COSTS

The serials pricing crisis—and its underlying causes—is now being recognized. The alarm was sounded several years ago when librarians discovered that some British publishers were adding hefty differential subscription charges to their North American customers. Almost immediately serials librarians at a few libraries began to analyze the problem. The libraries at the Universities of Michigan and Louisiana State constructed databases from which valuable information could be gleaned. This information was used to explain the full dimensions and implications of a problem that was already well on the way to becoming a full‐blown crisis.
Multiplication noise in the human visual system at threshold: 1. Quantum fluctuations and minimum detectable energy

We have carried out a series of frequency-of-seeing experiments similar to those performed by Hecht, Shlaer, and Pirenne [ J. Gen. Physiol.25, 819– 840 ( 1942)], using an Ar+ laser operated at 514.5 nm as the source of light. In certain blocks of trials, our subjects were encouraged to report as seen those trials in which the stimulus might have been present. It was determined that sensitivity and reliability were traded against each other over a broad range: for our four subjects, the detection of 147 photons at the cornea with 60% frequency of seeing entailed, on the average, a 1% false-positive rate (FPR), whereas the detection of 34 photons at the cornea with 60% frequency of seeing was accompanied by a 33% FPR. A new neural-counting model has been developed in the framework of signal-detection theory. It combines Poisson stimulus fluctuations with additive and multiplicative neural noise, both of which are known to be present in the visual system at threshold. The resulting probability-of-detection curves, derived from the Neyman Type-A counting distribution, are in good accord with our experimental frequency-of-seeing data for sensible values of the model parameters. We deduce that, on the average, our four subjects are able to detect a single photon at the retina with 60% frequency of seeing, at the expense of a 55% FPR. In Part 2 of this set of papers [ PrucnalP. R.TeichM. C., Biol. Cybern.43, 87– 96 ( 1982)], we use the normalizing transform, together with probit analysis, to provide improved estimates of threshold parameters, whereas in Part 3 [ TeichM. C.PrucnalP. R.VannucciG.BretonM. E.McGillW. J., submitted to Biol. Cybern.], we consider the effects of non-Poisson quantum fluctuations.
Development of the head skeleton and pectoral girdle in Esox.

A consideration of head development in two species of Esox, lucius and americanus (ssp. vermiculatus) representing the two subgenera Esox and Kenozoa respectively, focused on the significance of the variations of the latero-sensory canal system, its associated bones, and other skeletal elements. In living forms only aspects of “regression” or specialization can be studied. Canals tend to be reduced to pit lines first at their termini but can be broken in their course. Pit lines range from nearly canals to surface structures, or even fail to develop. The number of neuromasts varies. Canal bones develop from two centers: neuromast related and deeper membranous centers which may have no relationship to neuromasts. Tooth-bearing and non-canal-related dermal bones have only membranous (original) centers. The number of neuromasts associated with a bone usually does not affect its development or form. In the case of the circumorbital bones, the extrascapulars, and the nasal, a one to one relationship has developed by regression – towards the development of the latero-sensory component only. The idea that reductions in bone number are commonly traceable to fusion is rejected although examples of fusion are known. Most bones that disappear are simply lost (no blastema or other evidence of their presence seen in development). The relationship between dermal bone and chondral bone is examined and there is evidence of the former giving rise to the latter. The ontogenic order of appearances shows a feeding (functional) correlation.
Morphine synergizes with lipopolysaccharide in a chronic endotoxemia model

Abstract Emergent or elective surgical procedures may be complicated by sepsis, resulting in critical illness that can lead to organ failure and death. The opioid drug, morphine is widely used to alleviate pain in post-surgical patients; however, it is well documented that chronic treatment of mice with morphine affects the proliferation, differentiation and function of immune cells. Thus, morphine might be expected to exacerbate the effects of sepsis, which also compromises the immune system. To test this notion, we investigated the effect on several immune functions of a clinical dose of morphine (4 mg/kg) superimposed upon a lipopolysaccharide (LPS)-induced infection model. Our results show that this relatively low dose of morphine, though generally having no effects on immune parameters by itself, significantly augmented LPS responses. A clinical dose of morphine (4 mg/kg body weight) superimposed upon an animal model of sepsis resulted in a significant increase in mortality at 48 h. In the absence of the drug, most septic animals died after 96 h. Phenotypic responses such as, decreased thymic cellularity, compromised mitogenic response and inhibition of IL-2 synthesis that are evident at 48–72 h after LPS injection appear as early as 24 h in animals that receive morphine in addition to LPS. In addition, our results show that in T cells there is a shift from TH1 type cytokine elaboration to a TH2 type cytokine elaboration in animals that receive both LPS and morphine.
The effect of pressure on thermal and Fickian diffusion of sodium chloride

Abstract Measurements of the thermal diffusion (Soret) coefficient of sodium chloride in 0·5 N (28·5%) aqueous solution at pressures from atmospheric to 0·727 kbar and temperatures from 2 to 52°C reveal a large, positive change with pressure. At low temperatures the coefficient even changes sign as pressure is increased. The salt diffusivity, on the other hand, shows little variation with pressure. Both vary significantly with temperature. The Soret coefficient can be represented by the formula 10 −5 [(−119 + 11·05 T − 0·064 T 2 ) + P (320 − 8·48 T + 0·0532 T 2 )]°C −1 and the salt diffusivity by 10 −7 (62 + 3·63 T )cm 2 s −1 , where T is the temperature in degrees Celsius and P the pressure in kilobars.
Pulmonary hypertension in neonatal cystic lung disease: Survival following lobectomy and ECMO in two cases☆

Extracorporeal membrane oxygenation (ECMO) is an accepted form of therapy in the treatment of neonates with otherwise lethal persistent pulmonary hypertension related to meconium aspiration, congenital diaphragmatic hernia, and sepsis. This report concerns two neonates with congenital cystic lesions of the lung who developed severe pulmonary hypertension and were salvaged with lobectomy and ECMO. These cases present an additional group of patients in whom ECMO may be a life-saving measure.
Selection in chickens for retrogression of tumors caused by Rous sarcoma virus.

Abstract SEVERAL investigators have conducted selection studies for resistance and susceptibility of chickens to avian leukosis. Hutt et al. (1941, 1945), Taylor et al. (1943), Waters (1945), McClary et al. (1951) and Bearse et al. (1963) all reported varying degrees of success in selecting divergent lines, from the same original stock, for resistance and susceptibility to avian leukosis complex. The duration of these selection experiments ranged from four to twenty-eight generations. The basis of selection most often used was full-sib family selection, while progeny testing was employed in some studies. The criterion of selection was the percentage mortality from all forms of leukosis during the rearing and laying periods. Natural exposure was usually the sole means of challenge. In a few instances, tumor material was placed in the drinking water. Cole (1968) demonstrated rapid progress in selecting two divergent lines for resistance and susceptibility to Marek’s disease. The birds were challenged…
Cantilever springs: Force system and clinicalapplications

Abstract Cantilever springs are simple and efficient orthodontic appliances with a wide variety of clinical uses. Biomechanically, cantilevers are able to produce statically determinant force systems, giving the clinician the opportunity to deliver qualitatively and quantitatively precise forces. Cantilever springs have a large range of clinical applications. They can be used in first-, second-, and third-order problems. The basic design of cantilever springs and their various clinical applications are discussed.
Albumin uptake by renal lymphatics with and without obstruction of the renal vein

Abstract Experiments involving injection of radio-iodinated albumin into the left renal arteries or left ureters of dogs indicate that the renal lymphatics are capable of a major contribution in returning to the circulation albumin (or other large molecules) escaping from renal capillaries. I 131 -albumin was injected into the jugular vein of controls or into the left renal artery or in retrograde manner into the left ureter of female dogs. Experimental groups included those with no obstruction, occlusion of left renal veins or left renal lymphatics, or both. Collections were made from the right femoral artery, both renal veins, thoracic duct and both ureters at frequent intervals for 2 to 4 hours. Data analysis included I 131 concentration, specific activity, rate of recovery and selected ratios. After renal arterial injection, the percentage of I 131 recovered in thoracic duct lymph of dogs without renal venous obstruction was 5 to 10 times that recovered in those that received injections into the jugular vein. In dogs with renal venous obstruction, recovery from the thoracic duct was 10 to 1,000 times that in control dogs. Most of the differences occurred during the first hour, after which time as recirculation and redistribution occurred the rates of appearance in thoracic duct lymph in each group were similar. The differences in the ratios of concentration in thoracic duct lymph to concentration in femoral arterial blood were also much greater when the renal vein was obstructed than in dogs with no obstruction. The greater return of albumin through the thoracic duct in those with impeded renal venous outflow was probably related to both sequestered concentration and increased intrarenal pressure. With only renal lymphatics obstructed, because of vascular recirculation and labeled albumin uptake and return in lymph from other areas of the body, any decrease in return from the kidney was masked and results were similar to those with no obstruction. With both lymphatics and veins obstructed, no I 131 appeared in thoracic duct lymph or in blood. The results are compatible with the concept that disordered lymphatic uptake and flow contribute to nephropathies in which there is accumulation of protein in the kidney or loss in the urine.
Somatic Cell Mating and Segregation in Chimeric Frogs

Both pentaploid and haploid cells were observed in a short-term culture of bone marrow of a diploid-triploid frog chimera. Apparently, diploid and triploid marrow cells fused to form "hybrid" pentaploid cells, which subsequently gave rise by somatic reduction to haploid daughter cells. The hybrid marrow cells and their haploid segregants are presumably at a selective disadvantage, as neither type of cell has been detected in the circulating blood of chimeric frogs.
Distribution of charged defects in a:SiH n-i Schottky barrier solar cells

Abstract Nickel n-i Schottky barriers solar cell structures with i-layer thicknesses between 1.0 and 2 μm were characterized by dark I – V 's at different temperatures and internal quantum efficiencies (QE). These characteristics were modeled using AMPS (analysis of microelectronic and photonic structures) with charged defect distributions which were derived from results on corresponding i-layer films. This self-consistency was obtained with distributions of gap states which consist of charged defects where dangling bond states are represented by three Gaussians: positively charged D + above mid-gap; neutral D 0 around mid-gap; and negatively charged D − below mid-gap. Excellent fits to the results on Schottky barriers and films can be obtained with these bulk distributions of gap states which is not true for the commonly used two Gaussian D − , D 0 gap state distributions.
Evidence against melanin as the mediator of retinal phototoxicity by short-wavelength light.

Abstract Albino and pigmented (black-hooded) rats of the Sprague-Dawley and Long Evans strains, respectively, were compared in terms of their susceptibility to retinal damage by ultraviolet-A light. Anesthetized animals were exposed to ultraviolet-A light ( λ max = 360 nm) for 4 hr and retinal damage was assessed 1 week later by electroretinographic analysis and measurement of outer nuclear layer thickness. Albino and pigmented animals showed approximately the same severity of ultraviolet-A retinal damage as a function of exposure irradiance. Furthermore, both pigmentation strains showed swelling and vesiculation of rod inner segment mitochondria as an early manifestation of damage. An abbreviated study on a congenic rat strain (F344- c /+) of albino and pigmented littermates again demonstrated an equal susceptibility to ultraviolet-A phototoxicity for both pigmentation phenotypes. These findings provide evidence that melanin is not the mediator of short-wavelength phototoxicity to the retina, since damage readily occurred in albino animals completely lacking this chromophore.
Effects of lung inflation on airway heterogeneity during histaminergic bronchoconstriction

Lung inflation has been shown to dilate airways by altering the mechanical equilibrium between opposing airway and parenchymal forces. However, it is not known how heterogeneously such dilation occ...
Error-budget paradigms and laser mask pattern generator evolution

The evolution of the ALTA (R) series of laser mask pattern generators has increased the relative contribution of intensity errors on critical-dimension (CD) control to those from placement errors. This paradigm shift has driven a change in rasterization strategy wherein aerial image sharpness is improved at the cost of a slight decrease in the averaging of column-to-column placement errors. Print performance evaluation using small-area CD test patterns show improvements in stripe-axis local CD uniformity (CDU) 3σ values of 15-25% using the new strategy, and systematic brush-error contributions were reduced by 50%. The increased importance of intensity errors, coupled with the improvement of ALTA system performance, has also made the mask-blank and process-induced errors a more significant part of the overall error budget. A simple model based on two components, a pattern-invariant footprint and one related to the exposure density ρ (x, y), is shown to describe adequately the errors induced by these sources. The first component is modeled by a fourth-order, two-dimensional polynomial, whereas the second is modeled as a convolution of ρ (x, y) with one or more Gaussian kernels. Implementation of this model on the ALTA 4700 system shows improvements in global CDU of 50%.
Phonon effects on sharp luminescence lines of Nd3+ in Gd3Sc2Ga3O12 garnet (GSGG)

Abstract The widths, positions and shapes of sharp luminescence lines of the Nd3+ ion in GSGG:Cr3+, Nd3+ were measured carefully from 78 to 600 K. The sharp lines studied correspond to the R2 → Y1, R2 → Y1, R2 → Y3, R1 → Y2, R2 → Y6, R1 → Y6 and R1 → Z5 transitions. All the lines shift to the red with increasing temperature except for the R1 → Z5 line which shifts to the blue. The temperature dependence of line widths and line shifts is explained in terms of an ion-phonon interaction as a perturbation and of a Debye phonon distribution. The Debye temperature is treated as an adjustable parameter to get the best fit to the experiment data. The line widths are related to Raman scattering of phonons, direct phonon processes and statistical local strain of the crystal. The line shifts are due to the stationary effect of the ion-phonon interaction. The Debye temperature of GSGG is estimated to be 500 K through the fittings of the theoretical formulas to the experimental data.
Spectrophotometric determination of palladium and platinum with dibenzyldithio-oxamide

Abstract Palladium II and platinum II form water-insoluble coloured complexes with dibenzyldithio-oxamide which are extractable into chloroform. Factors affecting the analytical use of this reagent have been investigated. The yellow palladium complex and the rose-coloured platinum complex show absorption maxima at 450 and 520 mμ, respectively. Beer's law is obeyed over the range investigated, and a close control of conditions of colour development is not necessary. The tolerance to a number of diverse ions has been established with favourable results. A procedure for the simultaneous determination of palladium and platinum has been developed.
Developmental roles of tribbles protein family members

The gene tribbles (trbl), identified 12 years ago in genetic screens for mutations that control both cell division and cell migration during embryonic Drosophila development, is the founding member of the Tribbles (Trib) family of kinase-like proteins that have diverse roles in cell signaling, tissue homeostasis, and cancer. Trib proteins share three motifs: (1) a divergent kinase region (Trib domain) with undetermined catalytic activity, (2) a COP1 site used to direct key target proteins to the proteosome for degradation, and (3) a MEK1 site that binds and modulates MAPKK kinase activity. The notion that Tribs act as scaffolding proteins to balance signaling levels in multiple pathways retains an attractive simplicity, but given recent data showing that divergent kinases act by means of novel catalytic mechanisms, the enzymatic activity of Tribs remains untested. Here, we focus on the role of Tribs during development. Developmental analysis of Drosophila trbl phenotypes reveals tissue-specific, sometimes contradictory roles. In mammals, multiple Trib isoforms exhibit overlapping and tissue-specific functions. Recent data indicate the mechanism of Trib activity is conserved and requires the Trib domain. Finally, we discuss the connections between Tribs in disease and cancer that have implications for their normal roles during organogenesis.
Acute Cavitary Histoplasmosis

A case of acute cavitary histoplasmosis in the upper lobes is documented. The relationship of this entity to chronic cavitary histoplasmosis is discussed.
Flow patterns in liquid slugs during bubble-train flow inside capillaries

Bubble-train flow consists of strings of bubbles separated by liquid slugs flowing cocurrently inside capillaries of circular or square cross section. Bubble-train flows have interesting properties and have been used to enhance heat and mass transfer rates inside capillaries. The quantitative analysis of heat and mass transfer processes related to this flow requires a detailed knowledge of flow patterns inside the liquid slugs. High-speed video imaging was used to characterize liquid flow patterns. Velocity distributions inside liquid slugs were determined by particle imaging velocimetry (PIV). Video images recorded in a reference frame moving with the bubbles indicate the presence of recirculating patterns with a high degree of mixing. Depending on the capillary number of the flow, counter rotating vortices or a complete bypass flow inside the liquid slug were observed. The position and size of these vortices and the magnitude of the liquid velocity can be accurately predicted by theory. Mixing inside the liquid slug can be characterized by the average recirculating time of a particle of fluid trapped in the liquid vortex.
Heme-deficient mutants of Salmonella typhimurium: Two genes required for ALA synthesis

The first step in heme biosynthesis is the formation of 5-aminolevulinic acid (ALA). We have isolated, mapped and characterized a large number of Salmonella typhimurium mutants auxotrophic for ALA. These mutants carry defects in either one of two genes, both required for ALA synthesis. The previously identified hemA gene maps at 35 min, and the hemL gene maps at 5 min on the S. typhimurium genetic map. Mutants in hemA and hemL are defective for aerobic and anaerobic respiration, and appear to be oxygen sensitive. The Hem− phenotype of hemL mutants is less severe than that of hemA mutants. Although hemA and hemL mutants are deficient in heme synthesis, genetic tests indicate that they still synthesize two minor products of the heme pathway, siroheme and cobalamin (vitamin B12), under anaerobic conditions. In contrast, hemB, hemC and cysG mutants, blocked after ALA synthesis, make neither siroheme nor vitamin B12. Double mutants defective in both hemA and hemL also make siroheme. We suggest that hemA and hemL are required for one route of ALA synthesis and that a second, minor route of ALA synthesis may operate in S. typhimurium; this second pathway would be independent of the hemA and hemL functions.
Relaxation-matrix analysis of the transferred nuclear Overhauser effect for finite exchange rates

Abstract A matrix formalism is developed for calculations of time-dependent nuclear Overhauser effects in systems undergoing chemical exchange, and the analysis is applied to the interpretation of data obtained in transferred-NOE experiments. Simulations have been performed for a wide variety of nuclear geometries, and preliminary data for the reversible binding of the inhibitor tubercidin to bacterial purine nucleoside phosphorylase have also been obtained. Although theoretically the initial buildup rate of the NOE interaction is independent of the exchange-rate constant k, this independence persists for such a short period of time that it is experimentally unobservable unless the exchange rate is extremely high. For the parameters used in the models, calculated buildup rates corresponding to mixing times of 10–100 ms exhibit a strong dependence on k. Of greatest interest is the observation that a lag in the development of the transferred NOE, generally believed to characterize indirect relaxation pathways, frequently is observable only at very high rates of chemical exchange and is so minimal as to be experimentally undetectable. Alternatively, a pronounced lag phase is predicted if the exchange rate is sufficiently slow that the observed NOE corresponds to only the free species. An apparent lag can also be predicted to result from the small negative NOEs of the uncomplexed species for some exchange parameters. The analysis has also been extended to include macromolecule (enzyme) protons, and several models for the effects of enzyme-mediated relaxation have been evaluated. These calculations, combined with the limited ability of the researcher to control most of the parameters involved in this type of study, suggest significant problems with interpretations based on initial rate measurements and strongly support the need for an independent determination of the rate of chemical exchange and for the use of model calculations such as those presented here in the interpretation of transferred-NOE studies.
Selective excitation of dressed atomic states by use of phase-controlled optical fields.

We have studied the response of atoms in a dilute collimated atomic beam to transient phase-controlled resonant excitation fields. We demonstrate that the use of such excitation makes it possible to place the atoms into stationary states of the coupled atom-field system. We show that these states, which are easily visualized in the two-level-atom vector model, are equivalent to the dressed states of resonance fluorescence theory. Studies of atoms in pure dressed states should allow interesting tests of basic atom-field interactions.