cssi/SciSciGPT-SciSciNet huggingface dataset:
Optimized motion estimation for MRE data with reduced motion encodes.

Motion estimation is an essential step common to all magnetic resonance elastography (MRE) methods. For dynamic techniques, the motion is obtained from a sinusoidal fit of the image phase at multiple, uniformly spaced relative phase offsets, , between the motion and the motion encoding gradients (MEGs). Generally, eight values of sampled at the Nyquist interval π/4 over [0, 2π). We introduce a method, termed reduced motion encoding (RME), that reduces the number of required, thereby reducing the imaging time for an MRE acquisition. A frequency-domain algorithm was implemented using the discrete Fourier transform (DFT) to derive the general least-squares solution for the motion amplitude and phase given an arbitrary number of . A closed form representation of the condition number of the transformation matrix which is used for estimating motion was introduced to determine the sensitivity to noise for different sampling patterns of . Simulation results confirmed the minimum error sampling patterns suggested from the condition number maps. The minimum noise in the motion estimate is obtained when the sampled are essentially evenly distributed over the range [0, π) with an interval π/n, where n is the number of sampled, or alternatively with an interval 2π/n over the range [0, 2π) which represents the Nyquist interval. Simulations also show that the noise level decreases as n increases as expected. The decrease in noise is the largest when n is small and it becomes less significant as n increases. The algorithm also makes it possible to estimate the motion from only two values of , which cannot be accomplished with traditional methods because sampling at the Nyquist interval is indeterminate. Finally, noise levels in motion estimated from phantom studies and in vivo results taken with different n agreed with that predicted by simulation and condition number calculations.
Age-related intraindividual performance variability with practice

Fluctuations in cognitive task performance in older individuals have been reported. To examine intraindividual variability as a function of practice, 34 younger and 34 older female participants, aged 20-30 years and 70-82 years, respectively, performed a reading span task 16 times over four sessions. Each individual's recall accuracy was analyzed over the practice trials. It was found that intraindividual variability occurred more frequently in older than younger individuals, and that fluctuations were more frequent in mid to later trials of practice. These findings were interpreted within a resource theory framework as evidence for age-related inefficient cognitive processing with practice.
Measuring Judgment Interaction with Displays and Automation

Methodologies for assessing human judgment in complex domains are important for design of both displays that inform judgments and automated systems that suggest judgments. This paper applies n-system Lens Model methods for evaluating human judgments, examining the impact of displays, and assessing the similarity between human judgments and the judgment policies used by automated systems. First, the need for and concepts underlying, judgment analysis are outlined. Then the n-system Lens Model and its parameters are formally described. This model is then used to examine a study of aircraft collision detection examined previously using standard ANOVA methods. Our analysis found the same main effects as the earlier analysis. However, the n-system Lens Model analysis provided greater resolution regarding the information relied upon for judgments, the impact of displays on judgment, and the attributes of human judgments that are - and are not - similar to judgments produced by automated system
Effects of stress tensor fluctuations upon focusing

We treat the gravitational effects of quantum stress tensor fluctuations. An operational approach is adopted in which these fluctuations produce fluctuations in the focusing of a bundle of geodesics. This can be calculated explicitly using the Raychaudhuri equation as a Langevin equation. The physical manifestation of these fluctuations are angular blurring and luminosity fluctuations of the images of distant sources. We give explicit results for the case of a scalar field on a flat background in a thermal state.
The dynamic tensile behavior of tough, ultrahigh-strength steels at strain-rates from 0.0002 s−1 to 200 s−1 ☆

Abstract The present study examines the strain-rate sensitivity of four high-strength, high-toughness steels at strain-rates ranging from 0.0002 s −1 to 200 s −1 : AerMet 100, modified 4340, modified HP9-4-20, and a recently developed Eglin AFB steel alloy, ES-1c. A newly developed dynamic servohydraulic method was employed to perform tensile tests over this entire range from quasi-static to near split-Hopkinson or Kolsky bar strain-rates. Each of these alloys exhibits only modest strain-rate sensitivity. Specifically, the semi-logarithmic strain-rate sensitivity factor β was found to be in the range of 14–20 MPa depending on the alloy. This corresponds to a ∼10% increase in the yield strength over the 6-orders of magnitude change in strain-rate. Interestingly, while three of the alloys showed a concomitant ∼3–10% drop in their ductility with increasing strain-rate, the ES-1c alloy actually exhibited a 25% increase in ductility with increasing strain-rate. Fractography suggests the possibility that at higher strain-rates ES-1c evolves towards a more ductile dimple fracture mode associated with microvoid coalescence.
Vitamins in health and aging.

Food is essential to survival and health. Our ability to expend energy depends on adequate intake of protein and calories; however, even when adequate calories are available, nutritional deficiency diseases can occur. Historically, physicians observed that a number of peculiar disease states, such as scurvy, pellagra, and beriberi, were directly related to dietary intake. These diseases were found even in the presence of adequate calorie and protein intake. These strange nutritional deficiency states perplexed researchers until the turn of the century. A brief history of vitamins Scurvy was known to be cured by lemons and limes by 1753, but was not recognized as a nutritional deficiency. The improvement with citrus fruits was attributed to a presumed effect as an aid to digestion. With the ability to synthesize organic compounds around the turn of the nineteenth century, researchers believed that food could be produced in the laboratory as well as in nature. An adequate diet could be manufactured by combining purified protein, carbohydrates, and fats, with inorganic salts and water; however, experimental animals fed purified organic compounds failed to thrive. In one of the earliest experiments in 1881, Lunin found that young mice did not grow when fed an apparently adequate amount of organic compounds. The demonstration in the late nineteenth century that bacteria are responsible for human disease focused attention on food storage and preservation. Polished rice, which is more resistant to decay with the husk removed, represented a storage improvement over unpolished rice; however, a peculiar polyneuritis, later identified with beriberi, developed in chickens fed a diet of polished rice. In 1884, Christine Eijkman demonstrated that this polyneuritis could be prevented or cured in fowl by feeding them unpolished rice instead of polished rice.
The number of large prime divisors of consecutive integers

Let ϵ(N) > 0 be a function of positive integers N and such that ϵ(N) → 0 and Nϵ(N) → ∞ as N → + ∞. Let NνN(n:…) be the number of positive integers n ≤ N for which the property stated in the dotted space holds. Finally, let g(n; N, ϵ, z) be the number of those prime divisors p of n which satisfy NZϵ(N) ⩽ p ⩽ Nϵ(N), 0 < z < 1 In the present note we show that for each k = 0, ±1, ±2,…, as N → ∞, lim vN(n : g(n; N, ϵ, z) − g(n + 1; N, ϵ z) = k) exists and we determine its actual value. The case k = 0 induced the present investigation. Our solution for this value shows that the natural density of those integers n for which n and n + 1 have the same number of prime divisors in the range (1) exists and it is positive.
Introduction: Survey and Experimental Research in International Political Economy

Studies in international political economy (IPE) that use survey-response data sets and survey (or field) experiments have grown dramatically in recent years. New developments in survey and experim...
Strontium-90 Plasma-levels and Excretions in Young Adults

WITH the future of atmospheric testing of nuclear weapons uncertain, it remains of interest to determine in man the metabolism of strontium-90 derived from past tests. Considerable information on strontium-90 retention has been obtained from analysis of human bones1,2 and teeth3, from work with animals, from the metabolism of stable strontium4,5, and from the use in man of strontium-856,7. This communication reports some implications of a study of strontium-90 metabolism conducted on ten young adult volunteers who received a constant diet containing approximately 1.1 g of calcium per day on a metabolic ward for 3 periods of 6 days each. The intake of strontium-90 during the study averaged 13.4 µµc./day, most of it ingested with milk. Prior to the study, less milk was probably consumed, and less strontium-90 ingested.
Batrachotoxin has no effect on the electrogenic membranes of lobster and crayfish muscles

Abstract Batrachotoxin (BTX, 6.0 × 10 −7 M) has no effect on the resting membrane potential (RMP), action potential, or specific membrane resistance of lobster and crayfish muscle fibers bathed in normal physiological solutions or isotonic solutions in which sodium chloride was partially replaced by strontium chloride. The inability of BTX to affect the RMP and action potential of the crayfish muscle fibers was also observed when the preparation was either bathed in normal physiological solution or pretreated with tetraethylammonium bromide (205 mM) and bathed in tris(hydroxymethyl)aminomethane (236 mM) with calcium chloride (16 mM). It is concluded that BTX has no effect on the ionic permeability or on the electrogenic component of the action potential of the extensor muscle fibers of the walking leg of lobster and crayfish. This lack of BTX effect on these muscles suggests that a protein or proteolipid component that regulates the ionic permeability to calcium is not affected by the toxin.
The Impact of Lower Oil Prices on The Economies of Gulf States

The following is the edited text of his remarks to a Brookings Sadat Forum on April 21, 1999, at the Brookings Institution. The cosponsors are the Brookings Foreign Policy Program and the Anwar Sadat Chair for Peace and Development at the University of Maryland.
"Yo no sabía..."-immigrant women's use of national health systems for reproductive and abortion care.

Half of pregnancies worldwide are unintended; half of these end in abortion. Immigrant women encounter more obstacles to reproductive healthcare than non-immigrant women, and access to national healthcare is a particularly important factor in abortion access. Spain’s government recently liberalized abortion laws, including abortion services in the national health system available to immigrants. Evidence suggests that immigrant women in Spain experience difficulties navigating the health system—the impact of the changed abortion laws on immigrant’s women’s access to care is not yet clear. Through a literature review and analysis, this paper examines the experiences of immigrant women with national health systems, and their use of such systems for reproductive and abortion care, in order to explore what could be expected in Spain as the national health system expands to include abortion care, and to illuminate immigrant women’s experiences with using national health systems for reproductive healthcare more broadly.
An adaptive role for BDNF Val66Met polymorphism in motor recovery in chronic stroke.

Little is known about the influence of genetic diversity on stroke recovery. One exception is the polymorphism in brain derived neurotrophic factor (BDNF), a critical neurotrophin for brain repair and plasticity. Humans have a high-frequency single nucleotide polymorphism (SNP) in the prodomain of the BDNF gene. Previous studies show that the BDNF Val66Met variant negatively affects motor learning and severity of acute stroke. To investigate the impact of this common BDNF SNP on stroke recovery, we used a mouse model that contains the human BDNF Val66Met variant in both alleles (BDNFM/M). Male BDNF+/+ and BDNFM/M littermates received sham or transient middle cerebral artery occlusion. We assessed motor function regularly for 6 months after stroke and then performed anatomical analyses. Despite reported negative association of the SNP with motor learning and acute deficits, we unexpectedly found that BDNFM/M mice displayed significantly enhanced motor/kinematic performance in the chronic phase of motor recovery, especially in ipsilesional hindlimb. The enhanced recovery was associated with significant increases in striatum volume, dendritic arbor, and elevated excitatory synaptic markers in the contralesional striatum. Transient inactivation of the contralateral striatum during recovery transiently abolished the enhanced function. This study showed an unexpected benefit of the BDNFVal66Met carriers for functional recovery, involving structural and molecular plasticity in the nonstroked hemisphere. Clinically, this study suggests a role for BDNF genotype in predicting stroke recovery and identifies a novel systems-level mechanism for enhanced motor recovery.
Identification and Partial Characterization of Factor Va Heavy Chain Kinase from Human Platelets

Factor Va, the essential cofactor for prothrombinase, is phosphorylated on the acidic COOH terminus of the heavy chain of the cofactor, at Ser692, by a platelet membrane-associated casein kinase II (CKII). Consistent with this observation, phosphorylation of the factor Va heavy chain by the platelet kinase was inhibited by heparin. The membrane-associated platelet CKII kinase was partially purified using heparin-agarose, phosphocellulose, and ion exchange chromatography. CKII antigen was monitored using a polyclonal antibody to the alpha-subunit, and kinase activity in the various fractions was confirmed using human factor Va as a substrate. Immunoblotting experiments using polyclonal antibodies raised against synthetic peptides mimicking a portion of the deduced amino acid sequence of the alpha-, alpha'-, and beta-subunits of human CKII demonstrated the coexistence of both alpha- and alpha'-subunits in platelets and suggested that the platelet CKII kinase may exist in part as an alpha alpha'beta2 complex. It is also possible that there are two distinct populations of CKII in platelets, one that is alphaalpha/betabeta and one that is alpha'alpha'/betabeta. In the presence of the purified platelet-derived CKII, human factor Va incorporates between 0.8 and 1.3 mol of phosphate/mol of factor Va depending on the concentration of the beta-subunit in the kinase preparation. A peptide mimicking the sequence 687-705 of the human factor V molecule incorporates radioactivity in the presence of purified CKII and inhibits factor Va heavy chain phosphorylation by the platelet CKII. In contrast, a peptide with an alanine instead of a serine at position 692 neither incorporates phosphate nor inhibits factor Va phosphorylation by the platelet CKII. Human factor Va is inactivated by activated protein C following three cleavages of the heavy chain at Arg506, Arg306, and Arg679. Cleavage at Arg506 is necessary for efficient exposure of the inactivating cleavage site at Arg306. The phosphorylated cofactor has increased susceptibility to inactivation by activated protein C, since phosphorylated factor Va was found to be inactivated approximately 3-fold faster than its native counterpart. Acceleration of the inactivation process of the phosphorylated cofactor occurs because of acceleration of the rate of cleavage at Arg506. These data suggest a critical role for factor Va phosphorylation on the surface of platelets in regulating cofactor activity.
Do economic conditions influence environmental policy? Evidence from the US Senate

Abstract This paper investigates whether economic conditions influence environmental policy by examining how policymakers voting on environmental legislation respond to changes in their state’s unemployment rate. The outcome of interest is a US Senator’s League of Conservation Voters score, which reflects how often a senator voted for the environmentally-favorable outcome on bills related to the environment in a given year. I find evidence that a higher unemployment rate is associated with reduced support for environmentally-favorable policies and that the estimated response is largest for Republicans. Counterfactual estimates indicate that if each state had experienced its lowest observed unemployment rate throughout the sample, then the proportion of votes taking the environmentally-favorable outcome would have increased from 36% to 41%.
ENVIRONMENTAL AND BIOCHEMICAL CONTROL OF STOMATAL MOVEMENT IN LEAVES

Summary The chloroplasts of guard cells are largely responsible for the response of stomata to light. The opening movement is probably associated with the synthesis of ATP by non-cyclic photophosphorylation, and the obligatory fixation of carbon dioxide to produce glycolic acid. The oxidative metabolism of glycolic acid is related to ATP synthesis as well as to the possible formation of carbohydrate. In the absence of oxygen in the gas phase, stomata open poorly, and the synthesis of glycolic acid is also inhibited. α-Hydroxysulphonates, which are inhibitors of glycolate oxidase, prevent stomatal opening in a competitive manner. High concentrations of carbon dioxide close stomata and inhibit the formation of glycolic acid, and the effect of high carbon dioxide on closing can be reversed by providing the tissue with glycolic acid. When leaf hydration is not limiting, raising the temperature in the environment causes an increase in the steady state of the stomatal aperture. There is little effect of temperature on the rate of closing in darkness, hence opening is the active process. A large number of chemical inhibitors were found to prevent opening, either by interfering with metabolic reactions in the guard cells concerned with the ‘pump’ responsible for the increased turgidity, or by acting on the membranes that serve as a ‘check valve’. Sodium azide is a substance which acts by both mechanisms, but the maximal effect occurs at different concentrations, and experiments with this inhibitor have shown that the opening and closing reactions operate independently.
“My grain of sand for society”: neoliberal freedom, language learning, and the circulation of ideologies of national belonging

This article explores the ways in which neoliberal discourses of individual freedom and choice come to typify Mexican migrants’ talk about what it means to be living in the USA and about themselves as learners of English. Interviews with migrants about the English language program Ingles Sin Barreras [English without Barriers] provide the context for these discursive displays. Ingles Sin Barreras is advertized repeatedly throughout the day on Spanish language TV, and it is an English language program that comprises 12 books, workbooks, CDs, and DVDs. Ingles Sin Barreras acts as a storehouse for ideas about personal freedom, citizenship, and the importance of English in belonging to the USA as a nation.
Ultrasonic propagation above and below the martensitic transition in solid D 2

The change in the transmitted signal amplitude of longitudinal sound with temperature is studied in ${\mathrm{D}}_{2}$ upon thermally cycling a crystal, grown in the hcp phase, between 1.5 K and the melting point, before and after crossing the martensitic hcp-fcc transition. These and other experiments lead to the conclusion that an intermediate close-packed structure is progressively stabilized at the expense of the cubic phase above the transition until the melting point. This is contrary to conclusions from previous experiments and also in striking contrast with the behavior of ${\mathrm{H}}_{2}$. The orientation of the stacked planes, where the net sliding occurs during the transition, remains the same as in the original hcp crystal, but within each plane, the structure is undetermined.
Smoking and arterial stiffness in youth with type 1 diabetes: the SEARCH Cardiovascular Disease Study.

Objective To evaluate the effects of smoking on early markers of cardiovascular disease (arterial stiffness) in adolescents with and without type 1 diabetes (T1D) in the SEARCH Cardiovascular Disease Study. Study design Participants included 606 youth (18.9 ± 3.3 years, 83% non-Hispanic white; 50% male). Six groups were defined: (1) smokers with T1D (n = 80); (2) former smokers with T1D (n = 88); (3) nonsmokers with T1D (n = 232); (4) smokers without T1D (n = 40); (5) former smokers without T1D former (n = 51); and (6) nonsmokers without T1D (n = 115). Arterial stiffness measurements included pulse wave velocity (PWV), augmentation index, and brachial distensibility. Multivariate linear regression was used to assess the independent and joint effects of T1D and smoking on arterial stiffness. Results Nearly 20% of both youth with and without T1D and T1D were smokers. In youth without T1D, smokers had higher trunk and arm PWV. After adjustment for potential confounders, T1D, but not smoking, was an independent predictor of PWV ( P Conclusions We found a high prevalence of smoking among youth with and without T1D; however, smoking status was not independently associated with increased arterial stiffness in youth with T1D.
Comparison of two stocks of mice in spermatogonial response to different conditions of radiation exposure.

Abstract In a previous report (Generoso et al., 1985) it was shown that the two hybrid stocks of mice, (C3H/R1 × 101/R1)F 1 and (SEC/R1 × C57BL/6)F 1 , differed in their responses to induction of chromosomal aberrations following exposure of the stem-cell spermatogonia to 500 R × 4 (4-week intervals) acute X-rays. The levels of response in the two stocks were paralleled by the effects on the length of the sterile period, which presumably results from stem-cell killing and repopulation. The present study was conducted in order to determine whether the differences between the two stocks in these parameters hold true also for other conditions of radiation exposure. Thus, comparative experiments were conducted using the following acute exposure regimens: 500 R single dose, 500 R + 500 R (24-h interval), 100 R + 900 R (24-h interval), and 500 R × 4 (8-week intervals). The endpoints measured were chromosome rearrangements in diakinesis/metaphase-I meiocytes, embryonic lethality in conceptuses, length of sterile period and testis weight. Trend analysis indicated that higher frequencies of chromosome rearrangements and embryonic lethality were recovered from (C3H/R1 × 101/R1)F 1 than from (SEC/R1 × C57BL/6)F 1 males, that there were no significant differences between stocks in testis weight reductions, and that there was no consistency in the direction of the significant differences that occurred in the length of the sterile period. A definitive conclusion regarding the possible association between induction of chromosomal aberrations and induction of cell killing awaits direct histological analysis of the stem-cell population.
The U.S. Television Industry Concentration and the Question of Network Divestiture of Owned and Operated Television Stations

The U S television industry has often been labeled as being highly concentrated This article attempts to measure levels of seller, buyer, and "additional" concentration in the television station industry and then relates the findings to the Justice Department proposal to examine possible divestiture of the network owned and operated stations An oligopoly schema is used to test the hypothesis that, even when consideration is given to the three national networks in a measured value of concentration, the television industry is not a highly concentrated industry, i e , it would not be classified as a concentrated, type / oligopoly The measures support the conclusion that the television station industry does not have high seller and buyer concentration But, when consideration is given to an "additional" measure (the product representative function of the networks, i e , their networking functions involving program and advertisement sales), the industry was found to be highly concentrated The owned and operated...
Caramel colours—A historical introduction

Caramel colours used in the manufacture of a wide variety of foods and beverages have been an item of commerce for more than one hundred years. The regulatory history of these additives in the US, the UK, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and the EC is reviewed, and an introduction to the safety studies of caramel colours in this issue of Food and Chemical Toxicology is provided.
Effect of thoracic epidural anesthesia on spontaneous postinfarction ventricular dysrhythmia in awake dogs

Background and Objectives Sympathetic neural activity contributes to the genesis of ventricular ectopic activity, particularly in the setting of myocardial ischemia and infarction, so thoracic epidural anesthesia should diminish ventricular ectopy by blocking sympathetic innervation of the heart. However, the possible antidysrhythmic effect of epidural anesthesia has been studied only in the presence of general anesthesia. We therefore examined changes in spontaneous postinfarction ventricular dysrhythmia during thoracic epidural anesthesia in awake dogs. Methods A survivable myocardial infarction was created by two-stage ligation of the left anterior descending coronary artery. The following day, multifocal idioventricular tachycardia was the predominant cardiac rhythm. Lidocaine was administered either by thoracic epidural catheter to achieve block of at least the first five thoracic segments or intravenously as a control for direct effects, without concurrent general anesthesia or sedation. Electrocardiographic recordings were analyzed for the number of ventricular ectopic and sinoatrial depolarizations. Results Epidural and intravenous administration both produced plasma lidocaine concentrations of about 2 mg/mL. There was no change in rhythm following intravenous lidocaine. During epidural anesthesia, total ectopic beats per minute decreased from 167 ± 8 to 135 ± 14 (mean ±SE, P Conclusions Epidural block modestly reduces spontaneous ventricular dysrhythmia in a perioperative setting in dogs following a large myocardial infarction. These findings do not support the choice of thoracic epidural anesthesia for the purpose of preventing or decreasing severe ventricular dysrhythmia.
Effects of molecular size and configuration on diffusion in microporous membranes

Effects of molecular size and configuration on hindered diffusion were examined by measuring diffusion of two series of uncharged macromolecules through track-etch membranes with uniform and well-defined pore geometry. At any given Stokes-Einstein radius, diffusivities in small pores were lower for ficoll (crosslinked structure) than for dextran (more nearly linear structure).
Anomalous dispersion of rhodopsin in rod outer segments of the frog

Linear-retardation spectra of single frog-rod outer segments were measured by use of a microspectrophotometer equipped with polarizing optics. The recorded transmitted-flux variation was reduced to a rhodopsin anomalous-dispersion spectrum by use of the Jones calculus. This anomalous dispersion is compared with theoretical predictions.
Scattering of light by molecules over a rough surface

We present a theory for the multiple scattering of light by obstacles situated over a rough surface. This problem is important for applications in biological and chemical sensors. To keep the formulation of this theory simple, we study scalar waves. This theory requires knowledge of the scattering operator (t-matrix) for each of the obstacles as well as the reflection operator for the rough surface. The scattering operator gives the field scattered by the obstacle due to an exciting field incident on the scatterer. The reflection operator gives the field reflected by the rough surface due to an exciting field incident on the rough surface. We apply this general theory for the special case of point scatterers and a slightly rough surface with homogeneous Dirichlet and Neumann boundary conditions. We show examples that demonstrate the utility of this theory.
THE REPORT OF THE ROYAL COMMISSION ON TAXATION

I T Is SAFE to say that no nation’s tax system has been subject to an analysis as exhaustive as that of the Carter Commission. The recommendations of the majority of the Commission are bold and extremely far-reaching. To the academic student of taxation they appear to embody virtually all of the reform measures advocated by Professors Henry C. Simons and Robert Murray Haig and most of their followers, buttressed by the tenets of welfare economics and neo-Keynesian fiscal policy. The Commission’s Report is, in consequence, a truly remarkable document, one that provides the critic with few substantial targets for his barbs. Even these few are, more often than not, at least implicitly recognized in the Report and generally remain because the Commission seems to have refrained at some points from pursuing with unrestrained boldness the directions dictated by its own basic premises. It is clearly impossible to summarize, much less evaluate, all of the conclusions and recommendations contained in the six volumes and 2,600 pages of the Report. I shall focus briefly, first, on the objectives set forth by the Commission, then examine those recommendations that seem to me to be of greatest importance, and finally, I shall take issue with the Commission on some of its sins of omission.
On a deterministic theory of estimation and control

A feedback control system can be structured for linear nonstationary process and measurement systems comprising a deterministic filter whose output is the independent variable of a linear control law. Subject to uniform controllability and observability, the filter and control gains can be specified to provide arbitrary and separable stability properties. If the filter gain is selected to produce a stabilizing effect on the state estimate, and the control gain is selected to produce a stabilizing effect on the process, the filter and control gains are shown to satisfy matrix Riccati differential equations. This suggests the use of stochastic optimal control theory when there is no quantitative measure of optimality, but it is desirable to assure the qualitative property that feedback be stabilizing. A concise derivation of the Kalman-Bucy filter is included in an appendix to illustrate the facility of approaching optimal estimation problems with the methods of stability theory.
Computers, Learning Outcomes, and the Choices Facing Students

We model the tradeoff students face between devoting time to coursework and time for other activities. We show how the model can be used to identify whether computers are productive tools and whether students will learn more when using computers. We present our own empirical findings, in a case study focusing on college composition. Only one-sixth of the students in our study fall into the category indicating that the computer was a productivity enhancing tool even though more than half achieved the same or higher measure of learning.
Discursos utópicos y distópicos de amor y humor en la creación de la identidad caribeña

The article argues that the literary elite utilize love and humor, as themes, to make literature out of social-historic events or problems. This analysis examines the relation between humor and love in the construction and deconstruction of Caribbean identity. Love, humor and otherness entwine in the texts analyzed here to demonstrate the exclusion of minorities in the national project.
Using coupled subspace models for recovery of reflectance spectra from airborne images

The spectral radiance measured by an airborne sensor is dependent on the spectral reflectance of the ground material, the orientation of the material surface, and the atmospheric and illumination conditions. We present a nonlinear algorithm for estimating surface spectral reflectance of a surface on the ground from the spectral radiance measured by an airborne sensor. The nonlinear separation algorithm uses a low-dimensional subspace model for the reflectance spectra. The algorithm also considers the inter-dependence of the path radiance and illumination spectra by using a coupled subspace model. We have applied the algorithm to a large set of 0.4-1.74 micron sensor radiance spectra. We have examined the use of the recovered reflectance vectors for material identification over a database of materials from the US geological Survey (USGS) library. We also extend the nonlinear algorithm to estimate the reflectance spectra of materials having varying orientations. We have applied the algorithm to 0.42-1.74 micron sensor radiance spectra in digital imaging and remote sensing image generation (DIRSIG) model scenes that contain 3D objects.
Tripartite Mushroom Body Architecture Revealed by Antigenic Markers

We have explored the organization of the axonal lobes in Drosophila mushroom bodies by using a panel of immunohistochemical markers. These markers consist of antibodies to eight proteins expressed preferentially in the mushroom bodies: DAMB, DCO, DRK, FASII, LEO, OAMB, PKA RII, and RUT. Previous to this work, four axonal lobes, two projecting dorsally (alpha and alpha') and two medially (beta and gamma), had been described in Drosophila mushroom bodies. However, our analysis of immunohistochemically stained frontal and sagittal sections of the brain revealed three medially projecting lobes. The newly distinguished lobe, which we term beta', lies along the dorsal surface of beta, just posterior to gamma. In addition to resolving a fifth lobe, our studies revealed that there are specific lobe sets defined by equivalent marker expression levels. These sets are (1) the alpha and beta lobes, (2) the alpha' and beta' lobes, and (3) the gamma lobe and heel (a lateral projection formed by a hairpin turn of some of the peduncle fibers). All of the markers we have examined are consistent with these three sets. Previous Golgi studies demonstrate that each mushroom body cell projects one axon that branches into a dorsal lobe and a medial lobe, or one unbranched axon that projects medially. Taken together with the lobe sets listed above, we propose that there are three major projection configurations of mushroom body cell axons: (1) one branch in the alpha and one in the beta lobe, (2) one branch in the alpha' and one in the beta' lobe, and (3) one unbranched axon projecting to the heel and the gamma lobe. The fact that these neuron types exhibit differential expression levels of a number of mushroom body genes suggests that they may have corresponding functional differences. These functions may be conserved in the larvae, as several of these genes were expressed in larval and embryonic mushroom bodies as well. The basic mushroom body structure, including the denritic calyx, peduncle, and lobes, was already visible by the late stages of embryogenesis. With new insights into mushroom body organization, and the characterization of markers for developing mushroom bodies, we are beginning to understand how these structures form and function.
Family Reflections on Living through Sudden Death of a Child

The author describes a method of cooperative inquiry into a family’s experience of the sudden death of a child. Through the praxis method based on Newman’s health as expanding consciousness, family members had an opportunity, individually and together, to explore the impact of this experience on subsequent family life over three generations. Members were given transcripts of all dialogues for further reflection. All writings were shared with all family members. Both process and content of the inquiry will illustrate the shared and unique ways in which this loss was expressed over time. Implications of the mode of inquiry will be discussed.
Software design representation: design object descriptive attribute notation (DODAN)

An approach using frame/constraint for knowledge representation of software design is presented to facilitate software design acquisition and continued usefulness of design information. The representation is independent of the programming language used in software implementation and covers certain basic concepts of software design: control flow, data flow and data abstraction. These basic characteristics of a software design are specified using design object descriptive attribute notation (DODAN) and can be translated into an event-flow diagram based on the Petri-net semantics and a data-dependent diagram based on data-flow semantics. The run-time behavior of the software designed can be interpreted on the basis of the timing constraints. The translation and interpretation are done by sets of production rules. As consumers often change their demands, various dependent flow analyses can help software designers reuse previous designs, figure out the impact of the change, and rectify the design. >
Polyinstantiation integrity in multilevel relations

Polyinstantiation integrity (PI) as defined in the Sea View multilevel relational data model consists of a functional dependency component and a multivalued dependency component. It is shown that the latter component rules out many practically useful relations and is therefore unduly restrictive. This leads the authors to propose that PI be defined to consist only of the functional dependency component. For this revised definition of PI, they formulate and prove correct a lossless decomposition of multilevel relations into single-level ones with recovery based on the natural join operation. >
Gene Expression in the Human Mammary Epithelium during Lactation: the Milk Fat Globule Transcriptome

The molecular physiology underlying human milk production is largely unknown because of limitations in obtaining tissue samples. Determining gene expression in normal lactating women would be a potential step toward understanding why some women struggle with or fail at breastfeeding their infants. Recently, we demonstrated the utility of RNA obtained from breast milk fat globule (MFG) to detect mammary epithelial cell (MEC)-specific gene expression. We used MFG RNA to determine the gene expression profile of human MEC during lactation. Microarray studies were performed using Human Ref-8 BeadChip arrays (Illumina). MFG RNA was collected every 3 h for 24 h from five healthy, exclusively breastfeeding women. We determined that 14,070 transcripts were expressed and represented the MFG transcriptome. According to GeneSpring GX 9, 156 ontology terms were enriched (corrected P < 0.05), which include cellular (n = 3,379 genes) and metabolic (n = 2,656) processes as the most significantly enriched biological process terms. The top networks and pathways were associated primarily with cellular activities most likely involved with milk synthesis. Multiple sampling over 24 h enabled us to demonstrate core circadian clock gene expression and the periodicity of 1,029 genes (7%) enriched for molecular functions involved in cell development, growth, proliferation, and cell morphology. In addition, we found that the MFG transcriptome was comparable to the metabolic gene expression profile described for the lactating mouse mammary gland. This paper is the first to describe the MFG transcriptome in sequential human samples over a 24 h period, providing valuable insights into gene expression in the human MEC.
The Garrod Lecture Evasion of antibiotic action by bacteria

Antibiotics have reduced the mortality from infectious diseases but not the prevalence of these diseases. Use, and often abuse, of antimicrobial agents encourages the evolution of bacteria toward resistance, often resulting in therapeutic failure. This evolution is due to the emergence of "new' resistance mechanisms and to the spread of well-characterized mechanisms of resistance to the majority of bacterial species. Bacterial resistance can be intrinsic or acquired. Intrinsic resistance is species or genus specific and delineates the spectrum of activity of the antibiotic. Acquired resistance is present in only certain strains of a species or of a genus. The latter results from mutation in a gene located in the host chromosome or a plasmid or from acquisition of new genetic information by a bacterium, mainly by conjugation or transformation. In this review, recent developments in the understanding of biochemical mechanisms and the genetics of resistance is considered for the clinically important antibiotic families.
Association of Late Gadolinium Enhancement and Degree of Left Ventricular Hypertrophy Assessed on Cardiac Magnetic Resonance Imaging With Ventricular Tachycardia in Children With Hypertrophic Cardiomyopathy.

There are limited data on the clinical significance of left ventricular (LV) mass and late gadolinium enhancement (LGE) in pediatric hypertrophic cardiomyopathy (HC). We reviewed cardiovascular magnetic resonance (CMR) studies of children with HC to investigate the associations between the extent and distribution of LGE and LV mass with ventricular tachycardia (VT) in children with HC. A blinded observer reviewed CMR studies for the presence and distribution of LV hypertrophy and LGE using a 17-segment model. The primary outcome was VT. LGE was present 17 of 33 subjects (52%). VT was present on outpatient Holter monitor or exercise stress test in 7 patients, of which 5 patients (71%) had LGE. Each additional segment of LGE was associated with an increase in the odds of VT (odds ratio [OR] 1.4, 95% CI 1.1 to 1.9) and fewer than 5 segments with LGE had 93% specificity for the presence or absence of VT (OR 0.06, 95% CI 0.01 to 0.5). VT was more common in patients with LGE in the apical septal (p = 0.03), basal inferoseptal (p 2.7 vs 50.9 ± 24.3 g/m 2.7 ; p = 0.03). Each centimeter of increased maximum LV thickness was associated with increased likelihood of VT (OR 2.9, 95% CI 1.2 to 6.8). In conclusion, in pediatric HC, CMR to evaluate the extent and pattern of LGE, LV mass index, and maximum LV thickness may help to identify children with HC at risk of VT.
Comparative Study on Bacteriostatic Action of Sulfanilamide, Sulfapyridine, Sulfanilyl-Sulfanilamide and Sulfathiazol upon Enterococci

At the present time it is not as yet possible to predict from the chemical composition of various sulfanilamide derivatives their chemotherapeutic activity toward different microorganisms that are more or less susceptible to the action of sulfanilamide. Thus, it is necessary to test the efficacy of new compounds both in vitro and in vivo. It is generally agreed that sulfanilamide in therapeutic doses has little or no effect on enterococci. Recently Helmholz1 reported that sulfathiazol and sulfamethylthiazol in urine are bactericidal toward enterococci. Hill2 found that sulfanilamide, sulfapyridine and sulfathiazol in a concentration of 100 mg % have a marked bacteriostatic or germicidal action upon relatively small numbers of alpha-Streptococcus fecalis in urine. This author made the important observation that sulfathiazol as present in urine after administration of the drug exerts greater bacteriostatic activity than the same amount added to normal voided urine. Long and Bliss3 observed that sulfanilamid...
Hemispherectomy for Intractable Epilepsy

Charts of 111 patients, ages 2 months to 20 years, who underwent hemidecortication for intractable unihemispheric epilepsy in the period 1975-2001 were reviewed at Johns Hopkins Hospital.
A tunable hybrid III-V-on-Si MOS microring resonator with negligible tuning power consumption

We demonstrate a novel hybrid microring resonator with an integrated III-V-on-Si metal-oxide-semiconductor (MOS) capacitor structure for essentially zero-power resonance tuning. Over 1,000,000,000 times better tuning efficiency than conventional thermal tuning approach has been achieved.
Development of Validated Computer-based Preoperative Predictive Model for Proximal Junction Failure (PJF) or Clinically Significant PJK With 86% Accuracy Based on 510 ASD Patients With 2-year Follow-up.

Study design A retrospective review of large, multicenter adult spinal deformity (ASD) database. Objective The aim of this study was to build a model based on baseline demographic, radiographic, and surgical factors that can predict clinically significant proximal junctional kyphosis (PJK) and proximal junctional failure (PJF). Summary of background data PJF and PJK are significant complications and it remains unclear what are the specific drivers behind the development of either. There exists no predictive model that could potentially aid in the clinical decision making for adult patients undergoing deformity correction. Methods Inclusion criteria: age ≥18 years, ASD, at least four levels fused. Variables included in the model were demographics, primary/revision, use of three-column osteotomy, upper-most instrumented vertebra (UIV)/lower-most instrumented vertebra (LIV) levels and UIV implant type (screw, hooks), number of levels fused, and baseline sagittal radiographs [pelvic tilt (PT), pelvic incidence and lumbar lordosis (PI-LL), thoracic kyphosis (TK), and sagittal vertical axis (SVA)]. PJK was defined as an increase from baseline of proximal junctional angle ≥20° with concomitant deterioration of at least one SRS-Schwab sagittal modifier grade from 6 weeks postop. PJF was defined as requiring revision for PJK. An ensemble of decision trees were constructed using the C5.0 algorithm with five different bootstrapped models, and internally validated via a 70 : 30 data split for training and testing. Accuracy and the area under a receiver operator characteristic curve (AUC) were calculated. Results Five hundred ten patients were included, with 357 for model training and 153 as testing targets (PJF: 37, PJK: 102). The overall model accuracy was 86.3% with an AUC of 0.89 indicating a good model fit. The seven strongest (importance ≥0.95) predictors were age, LIV, pre-operative SVA, UIV implant type, UIV, pre-operative PT, and pre-operative PI-LL. Conclusion A successful model (86% accuracy, 0.89 AUC) was built predicting either PJF or clinically significant PJK. This model can set the groundwork for preop point of care decision making, risk stratification, and need for prophylactic strategies for patients undergoing ASD surgery. Level of evidence 3.
Emergency department management of head injuries.

SUMMARY Head injuries are a frequent and important problem from the view of the emergency department physician as well as from the national public health perspective. Of the two million head injuries each year, many are so mild that the individual does not present to a physician. However, approximately 20 per cent are of sufficient magnitude to warrant hospitalization; these amount to more than 1000 head injury admissions each day across the country. The role of the emergency department is to guarantee that patients are triaged according to severity and that proper diagnosis and initial management are carried out expeditiously. The ultimate outcome in these patients depends, in large part, on how vigorously the emergency department fulfills this role. It is hoped that the triage system and early management protocols presented in this article will aid these goals.