cssi/SciSciGPT-SciSciNet huggingface dataset:
Adjustable Angle Beam Crossing System for Coherent Anti-Stokes Raman Spectroscopy

Coherent anti-Stokes Raman spectroscopy (CARS) has shown great promise as a technique for obtaining Raman spectra of samples in fluorescent matrices. Moreover, the high conversion efficiency of the technique means that analytical signals are strong and data acquisition rates can be, at least in principle, fairly rapid. However, CARS suffers from two serious experimental problems. The first is the presence of a large, broadband nonresonant background signal, which is often the ultimate limitation to sensitivity. The second problem is that the angle at which the pump and probe laser beams must intersect is a function of the dispersion of the sample. To obtain good CARS signals one must adjust the beams to near the optimum crossing angle.
The accessibility and utility of candidate character in electoral decision making

Abstract In U.S. elections, the competence and integrity of candidates for office are among the factors that influence both the choices made by voters and the subsequent outcomes of electoral contests. Although past research has demonstrated that candidate character is highly consequential, much less is known regarding how, and under what conditions, information about character influences the individual-level candidate evaluation. We explore these questions using data from a series of computer-based laboratory experiments and a national survey. Results reveal that attitudes regarding competence and integrity are highly accessible, and that information about competence and integrity strongly influences assessments of candidates. However, no evidence was found that candidate character functions as a default basis of candidate evaluation to be used when information regarding political considerations such as partisanshp and ideology are unavailable.
Carcinoma of the parotid gland associated with benign lymphoepithelial lesion (Mikulicz's disease) in Sjögren's syndrome

Adenocarcinoma of the parotid gland developed in a 66-year-old woman who also had Sjogren's syndrome, manifested by rheumatoid arthritis and marked xerostomia. The adenocarcinoma was a pleomorphic lesion but basically was an acinic cell adenocarcinoma. Metastatic tumor in cervical and axillary lymph nodes appeared as acinic cell adenocarcinoma or as poorly differentiated ductal carcinoma. The parotid gland harboring the tumor and the ipsilateral submaxillary gland both exhibited the typical histological features of diffuse benign lymphoepithelial lesion (Mikulicz disease). Although several instances of the development of lymphoma in patients with Sjogren's syndrome have been described, this case is the first reported occurrence of carcinoma in a salivary gland of such a patient. It also is the first known example of carcinomatous change in diffuse benign lymphoepithelial lesion of salivary glands although one carcinoma possibly arising in the nodular variety of benign lymphoepithelial lesion of the parotid gland was reported previously.
Urea-dependent Signal Transduction by the Virulence Regulator UreR

Identification of the environmental triggers involved in the expression of virulence genes is a fundamental objective in studies of bacterial pathogens. For uropathogens, urea, found in the urinary tract at concentrations of up to 500 mm, functions as an environmental signal. Urea freely diffuses into the bacterium Providencia stuartii and activates UreR, a member of the AraC family of transcriptional activators. Active UreR promotes transcription of virulence-associated urease genes and alerts the organisms of its immediate milieu. Thus, the UreR.urea complex has a dual role, acting as both a transcriptional activator as well as an environmental sensor. Here, we describe the molecular events associated with activation of gene expression by urea-bound UreR. The K(d) of the urea.UreR binding reaction was measured as 0.2 mm by fluorescence quenching assays, and the shape of the binding curve indicated a single specific urea-binding site on UreR. Histidine residues are critical for urea binding in urease, and therefore to identify the urea-binding site in UreR, five mutant UreR forms were generated with histidine to alanine substitutions. Two of the mutants (UreR(c)) exhibited a constitutive phenotype by both activating transcription and binding to DNA with an increased affinity in the absence of urea. The UreR(c) bound urea with an affinity similar to that of wild-type UreR. We concluded, therefore, that the mutations resulting in constitutive activity were not involved in the UreR.urea interaction. UreR was activated, then, either by binding urea or by histidine to alanine substitutions at one of two positions. Circular dichroism indicated little change in the structure of UreR when activated, and size-exclusion chromatography demonstrated that both rUreR and rUreR(c) were dimers in both the presence and absence of urea. Thus, the structural changes associated with activation are subtle.
Isomorphism of two realizations of quantum affine algebra\(U_q (\widehat{\mathfrak{g}\mathfrak{l}{\text{(}}n{\text{)}}})\)

We establish an explicit isomorphism between two realizations of the quantum affine algebra $$U_q (\widehat{\mathfrak{g}\mathfrak{l}{\text{(}}n{\text{)}}})$$ given previously by Drinfeld and Reshetikhin-Semenov-Tian-Shansky. Our result can be considered as an affine version of the isomorphism between the Drinfield/Jimbo and the Faddeev-Reshetikhin-Takhtajan constructions of the quantum algebra $$U_q (\mathfrak{g}\mathfrak{l}(n))$$ .
Left atrial diastolic dysfunction: A new complication after catheter ablation for atrial fibrillation?

a c p d t ( p n d P r p r n Atrial fibrillation (AF) is a complex phenomenon associated with electrical, contractile, and structural remodeling. Alhough paroxysmal AF may occur in patients with apparently tructurally normal atria, the most frequent clinical setting of ersistent AF is hypertension, coronary artery disease, heart ailure, and valvular heart disease. A common pathophysiolgy of these risk factors for AF is volume or pressure overload f the left atrium (LA). According to the concept termed echano-electrical feedback, increased hemodynamic load ay be associated with changes in myocardial segment length, hich in turn result in decreased resting diastolic potential, hanges in cardiac action potential (AP) contour, shortening of P duration, and development of afterdepolarizations that riginate in the region of greatest stretch. As shown in an animal model, excessive loading conditions lead to increased dispersion of atrial refractory periods, which predisposes to atrial fibrillation. A recent study by Yoshida et al showed that F dominant frequency (DF) is directly related to LA pressure n patients with persistent AF, and that LA pressure is an ndependent predictor of DFmax in the LA appendage. These ndings support the notion that atrial stretch may stabilize igh-frequency sources necessary for maintenance of AF. It is widely accepted that AF causes many hemodynamic bnormalities, including an irregular and often rapid venricular rate, decreased stroke volume, increased LA presure and volume, shortened diastolic ventricular filling eriod, and atrioventricular valvular regurgitation. To counter these deleterious hemodynamic consequences, AF ablation has evolved as an effective therapeutic strategy for patients with symptomatic AF. The goal of AF ablation is to allow synchronized and efficient transport of blood from the atria to the ventricles. In accordance with the Frank-Starling principle, atrial systole augments left ventricular (LV) stroke volume and cardiac performance. In theory, one of the benefits of radiofrequency catheter ablation for AF is more effective LA function. Given that ablation lesions, by their nature, result in LA scarring, prior studies have investigated the impact of radiofrequency
Predicting Transfer Performance: A Comparison of Competing Function Learning Models.

The population of linear experts (POLE) model suggests that function learning and transfer are mediated by activation of a set of prestored linear functions that together approximate the given function (Kalish, Lewandowsky, & Kruschke, 2004). In the extrapolation-association (EXAM) model, an exemplar-based architecture associates trained input values with their paired output values. Transfer incorporates a linear rule-based response mechanism (McDaniel & Busemeyer, 2005). Learners were trained on a functional relationship defined by 2 linear-function segments with mirror slopes. In Experiment 1, 1 segment was densely trained and 1 was sparsely trained; in Experiment 2, both segments were trained equally, but the 2 segments were widely separated. Transfer to new input values was tested. For each model, training performance for each individual participant was fit, and transfer predictions were generated. POLE generally better fit the training data than did EXAM, but EXAM was more accurate at predicting (and fitting) transfer behaviors. It was especially telling that in Experiment 2 the transfer pattern was more consistent with EXAM's but not POLE's predictions, even though the presentation of salient linear segments during training dovetailed with POLE's approach.
Effect of Ethnicity on the Age of Onset of the Male Voice Change

The purposes of this study were to describe the characteristics of the changing male voice in 4th, 5th and 6th grade students using Cooksey's maturation stages and, to compare the age-of-onset of the male voice change in African American, White, and Hispanic male students. Participants included volunteer 4th (n = 61), 5th (n = 73), and 6th grade male students (n = 63) from 2 urban elementary schools, 5 suburban elementary schools, 1 suburban middle school and 1 urban middle school in the North Texas region. The three ethnic groups represented in this study were: African American (n = 62), White (n = 58), and Hispanic (n = 77). Results indicated that approximately 46% of 4th grade participants, 62% of 5th grade participants, and 67% of 6th grade participants were classified as changing voices. A descriptively larger percentage of African American participants were classified as changing voices than Hispanic and White participants. Also, a larger percentage of African American and Hispanic participants were descriptively classified in the more advanced stages of the voice change than White participants. Urban African American, White, and Hispanic participants had a larger percentage of males classified as changing voices than suburban African American, White, and Hispanic participants. Results of a one-way, between subjects ANOVA revealed no significant main effect for ethnicity, F (2, 51) = .42, p = .66, η2 = .02. The overall mean age-of-onset for participants in this study was approximately 11.20 years of age.
Physical and biochemical factors affecting diapause in insects; especially in the European corn borer, Ostrinia nubilalis: a review

. Ostrinia nubilalis Hubner is characterized according to the type of diapause exhibited and the structural and physiological changes associated with the diapausing state. Effects of physical factors such as photoperiod, temperature, and relative humidity, as well as physiological and biochemical aspects such as the neurosecretory system and cyclic AMP involvement in diapause induction, maintenance, and break are reviewed. The possible roles of circadian oscillator and hourglass mechanisms associated with photoperiodism and the functioning of the biological clock of the insect are discussed.
Marijuana: Dose effects on pulse rate, subjective estimates of intoxication, free recall and recognition memory

The effect of marijuana on memory as measured by free recall and recognition, pulse rate and self ratings of intoxication was evaluated in 16 male volunteers. Marijuana containing 0, 5, 10 or 15 mg Δ9-THC was evaluated to all subjects by smoking in 4 sessions separated by a 1 week interval. Free recall was reduced in a dose related manner by the drug, but recognition memory was unaffected. A 2 sec word presentation rate produced inferior recall in comparison to a 4 sec rate, but this variable did not interact with drug condition. Intrusion errors increased following intoxication but this effect was not systematically related to dosage of Δ9-THC. Both pulse ratings of intoxication increased with dosage.
A Simplified Phonetic Alphabet for German

AS curious as it may sound, there is still considerable hesitation on the part of German teachers in the matter of using phonetic transcription in their beginners' classes. Whereas even in high schools French is quite frequently started off with a "phonetic drill," it seems to be anathema in most of our colleges to impress the students' mind graphically with the differences of articulation of German. This is a grave psychological error. It is true, of course, that an absolutely correct pronunciation can be acquired only by the constant and repeated practice of speaking. Yet it is an indisputable fact that in anything we are trying to learn we are more apt to use our eyes than our ears. The era has passed for us when it was possible to recite poetry after hearing it recited once, as was customary during the Middle Ages. Our whole training is different, and yet we expect our students to memorize the peculiarities of German pronunciation immediately at the beginning of the instruction. This is aggravated by the fact that the student already has certain acoustic associations with certain letters. The mispronouncing of z is too widespread to necessitate any comment. The student usually knows quite well that z has the sound-value of ts. But the acoustic association of the letter z known to him (English zeal, zero) is too strong and ever-presently active. Only when his attention is expressly called to it is his passive knowledge turned into active application. It is one of the most important tasks of the teacher to rid the student of these wrong associations. To the mind of the student the German letters and their sound-values are not as outstandingly different from English as, say, the French nasals. Speaking symbolically, one may say that English and German are like a faint red and a strong pink. If one sees these two colors next to each other it is very hard to differentiate between them.But if one intercalates a contrasting color, say, blue, the difference becomes noticeable at once. Thus, the student has to be made to realize from the very start that there are quite noticeable differences between the German sound-values and familiar English sound-values of the same letters. The student complains that he studies a number of words at home, only to discover that they are pronounced differently in class. Therefore, we have to provide our students with an intercalation that allows them to realize those differences not only clearly, but also permanently. That is the justification for, and the meaning of, a phonetic transcription. We have to keep in mind, however, that a phonetic transcription is to be but a means to an end. It would be ideal if we could teach our students German as well as phonetics in general. As it is, the use of a phonetic tran-
Unexpected Recovery After Robotic Locomotor Training at Physiologic Stepping Speed: A Single-Case Design

Abstract Spiess MR, Jaramillo JP, Behrman AL, Teraoka JK, Patten C. Unexpected recovery after robotic locomotor training at physiologic stepping speed: a single-case design. Objectives To investigate the effect of walking speed on the emergence of locomotor electromyogram (EMG) patterns in an individual with chronic incomplete spinal cord injury (SCI), and to determine whether central pattern generator activity during robotic locomotor training (RLT) transfers to volitional EMG activity during overground walking. Design Single-case (B-A-B; experimental treatment–withdrawal–experimental treatment) design. Setting Freestanding rehabilitation research center. Participant A 50-year-old man who was nonambulatory for 16 months after incomplete SCI (sub-T11). Interventions The participant completed two 6-week blocks of RLT, training 4 times per week for 30 minutes per session at walking speeds up to 5km/h (1.4m/s) over continuous bouts lasting up to 17 minutes. Main Outcome Measures Surface EMG was recorded weekly during RLT and overground walking. The Walking Index for Spinal Cord Injury (WISCI-II) was assessed daily during training blocks. Results During week 4, reciprocal, patterned EMG emerged during RLT. EMG amplitude modulation revealed a curvilinear relationship over the range of walking speeds from 1.5 to 5km/h (1.4m/s). Functionally, the participant improved from being nonambulatory (WISCI-II 1/20), to walking overground with reciprocal stepping using knee-ankle-foot orthoses and a walker (WISCI-II 9/20). EMG was also observed during overground walking. These functional gains were maintained greater than 4 years after locomotor training (LT). Conclusions Here we report an unexpected course of locomotor recovery in an individual with chronic incomplete SCI. Through RLT at physiologic walking speeds, it was possible to activate the central pattern generator even 16 months postinjury. Further, to a certain degree, improvements from RLT transferred to overground walking. Our results suggest that LT-induced changes affect the central pattern generator and allow supraspinal inputs to engage residual spinal pathways.
Sensory attributes and volatile components of stored strawberry juice

Juices from three strawberry cultivars were stored at 2°C and 25°C for 6 wk and evaluated for the sensory attributes fresh strawberry, strawberry-jam, off-flavor, green, and sweet. Fresh flavor declined while off-flavor increased during storage, with the largest changes occurring at 25°C. Juice color and ascorbic acid also degraded much faster at 25°C. Fifteen volatiles were measured using headspace solid phase microextraction and gas chromatography. 2,5-dimethyl-4-hydroxy-3(2H)-furanone and 2,5-dimethyl-4-methoxy-3(2H)-furanone were positively related to fresh flavor and negatively related to off-flavor, while -terpineol was inversely related to fresh flavor. These volatiles explained almost 90% of the variation for fresh and off-flavor attributes.
Training for Successful Group Work with Children: What and How To Teach

There is a critical need for facilitators of children's groups, and this shortage may be due to a lack of adequate training courses. The purpose of this article is to provide a framework for educators to develop a course to meet this training need. To develop a course in children's group work, instructors need to know what to teach as well as how to teach. Course content suggestions here include selection criteria and evaluation approaches as well as developmental and stage characteristics pertinent to group work with children. Teaching methods described involve observation, experiential activities, and supervision procedures.
Rate of Visual Information Pick-Up in Learning Disabled and Normal Boys

A span-of-apprehension task and a backward masking technique were combined to allow measurement of the apprehension span of learning disabled and normal boys at various time intervals following stimulus presentation. A comparison of subjects' rate of information pick-up revealed a slower rate for learning disabled boys. Results indicate that most visual information is processed between 10 to 50 msec. after presentation of the stimulus. The implications for eye movement training programs as being detrimental for learning disabled students are discussed. Span of apprehension reflects the amount of information a person can extract or process from a brief visual display. As a measure of attention, the concept has a long history beginning with the tachistoscopic exposure of letters (Woodworth, 1938). Usually only four or five letters were reported correctly even though many more were presented during a brief exposure. This limitation of four or five letters was found to be related to memory rather than perceptual constraints (Sperling, 1960). When subjects were asked to report letters appearing only in a certain part of the stimulus array (e.g., letters that only appeared in a certain row), the memory constraint was removed and their span of apprehension subsequently increased. From this research, the following two-component model of the span of apprehension has emerged (Estes, 1965): First, the information in the visual display is available for a few hundred milliseconds (msec.) before the afterimage decays. Second, a central processing mechanism which acts on the display operates only before the afterimage decays. Central processing indicates that the scanning process operates on an internal sensory afterimage; peripheral processing means that it operates on the external visual display through eye movements. Sperling's (1960) partial-report procedure was extended by Estes (1965) who proposed a quantitative measure of the span of apprehension based upon simple forced-choice responses to b ief visual exposures. Using a tachistoscope, he displayed a matrix of letters in which one of two target letters was embedded. Subjects were then asked to make a forced-choice letter-recognition response after briefly scanning the visual display. According to Estes, the span of apprehension, A, was defined as the number of letters scanned. In turn, the span, A, can be estimated from the actual number of letters in the display, D, multiplied by twice the number of correct SUSAN K. BRYANT, M.A., is a graduate assistant, Southern Methodist University. CURTIS W. MC INTYRE, Ph.D., is Associate Professor of Psychology, Southern Methodist University. MICHAEL E. MURRAY, Ph.D., is Adjunct Professor of Psychology, Southern Methodist
Review: Low-dose CT screening reduces lung cancer and mortality in current or former smokers

Source Citation Humphrey LL, Deffebach M, Pappas M, et al. Screening for lung cancer with low-dose computed tomography: a systematic review to update the US Preventive Services Task Force recommend...
POLARIZATION OF THE NEUTRONS FROM THE REACTION $sup 12$C(D,n)$sup 13$N AT THE 4-MeV RESONANCE AND BETWEEN 5.2 AND 6.2 MeV.

Angular distributions of the polarization of the neutrons from the $^{12}\mathrm{C}(d,n)^{13}\mathrm{N}$ reaction have been measured for the ground-state and first-excited-state transitions at six energies between 5.2 and 6.2 MeV. The characteristic shape of the polarization angular distribution for the ground-state neutrons that was previously observed to emerge at about 3.5 MeV persists in this energy region, indicating the predominance of a direct-reaction mechanism in producing the polarization. The measurements for the first-excited-state neutron group (${l}_{p}=0$ transfer) show polarizations with maximum values of +0.30 at the forward angles. The forward-angle data in the 4.6- to 5.8-MeV interval do not exhibit interference effects between compound-nucleus and direct-reaction processes. A careful investigation of the polarization on the isolated resonance at 4 MeV was also conducted. Interference effects between compound-nucleus formation and a direct-reaction mechanism are observable here even on the stripping peak. The resonance, however, does not appreciably distort the characteristic shape of the polarization arising from the direct-reaction process.
Space charge waves and ionospheric irregularities

Abstract The dispersion of space charge waves in a partially ionized plasma is investigated mainly for transverse propagation to both applied electro- and magneto-static fields, E0 and B0 respectively. The waves consist of six modes of which five are damped and only one increases with time. The wave of this mode in low frequency travels approximately as fast as the electron drift and causes a two stream instability which may explain the equatorial sporadic-E. Generally, the movement of irregularities in the ionosphere may also be interpreted in terms of this drift wave at the low frequency limit. Further, in the presence of a static charge-density gradient orthogonal to B0, a drift instability is induced by the space charge wave of this mode. The simple relation of the velocity of this drift wave to E0 suggests a fascinating possibility for finding E0 by tracking the movement of irregularities such as meteor trails or artificial Ba+ clouds released from rockets.
Hypersensitivity pneumonitis in a machinist.

Hypersensitivity pneumonitis (HP), or extrinsic allergic alveolitis, is a patchy, interstitial lung disease that involves an immunologic reaction of the lung to repeated inhalation of foreign antigens. In this report, we describe a machinist with exposure to metalworking fluids (MWFs) and biopsy-confirmed HP. Return to work, which could be equated with a retrospective workplace-specific bronchoprovocation test, proved that working within an environment in which MWFs were used was associated with clinical deterioration in the patient's pulmonary status and with clinical improvement after removal from exposure. Am. J. Ind. Med. 34:387–392, 1998. © 1998 Wiley-Liss, Inc.
Optimized search over the Gabor dictionary for note decomposition and recognition

Performing real-time note detection of multiple audio sources, such as guitar signals, is a difficult task due to the complex nature of these signals. For instance, guitar notes are close in pitch and the harmonic overtones of each note are strongly interlaced, thus preventing standard filtering techniques. In order to accomplish note detection, a harmonic matching pursuit algorithm has been used to decompose an audio signal in terms of elementary waveforms called harmonic atoms. These atoms are derived from the standard matching pursuit algorithm, and are part of an extended and overcomplete Gabor dictionary. In this paper, the search over Gabor dictionary is optimized by using signal modeling of the guitar signal in order to pre-calculate a parameter set; therefore avoiding a costly search over the extended Gabor dictionary. The parameter set defined for the proposed algorithm includes time-location, decay rate, frequency, scale and phase, which are calculated at the onset of each note played. This optimized algorithm is demonstrated through synthesized and real guitar signal examples. Considerable computational savings of this proposed algorithm over the harmonic matching pursuit algorithm are achieved.
The dynamics of predation risk assessment : responses of anuran larvae to chemical cues of predators

1. While the antipredator behaviour of prey has been well studied, little is known about the rules governing the predation risk assessment of prey. In this study, I measured the activity levels of predator-naive green frog (Rana clamitans) tadpoles during and after exposures to the chemical cue of predatory larval dragonflies (Anax spp.). I then used the lengths of the time lags from the end of the cue exposures until the tadpoles returned to a control level of activity as an index of the perceived risk of the tadpoles. 2. While tadpoles always responded upon exposure to the Anax chemical cue by strongly reducing their activity level, their perceived risk increased asymptotically over time during the initial period of the cue exposure. Tadpoles of all size classes perceived increasing risk in proportion to chemical cue concentration, but the length of time that tadpoles responded during cue exposure and the length of their post-exposure time lags decreased with increasing body mass. 3. The results suggest that the perceived risk of green frog tadpoles varies over time and does not correspond directly to their behavioural response (i.e. activity level). However, their perceived risk does appear to vary in accordance with the predation risk associated with the Anax chemical cue and the reliability of the information from the cue, and therefore may be predictable.
The Role of Structure and Content in Perception of Visual Similarity Between Web Pages

In human–computer interaction, users' perception of visual similarity in interfaces may affect how well they judge the relevance of information, construct appropriate mental models, and effectively interact with computers. This is of interest to both computer science and psychology. A review of the theoretical and applied research in visual similarity reveals both a content-oriented and a structural-oriented approach. The present study seeks to understand the content and structural aspects of visual similarity judgment. Unlike early theoretical studies in psychology, web pages were used as realistic stimulus in an experimental study. Structural and content changes to pairs of web pages were incrementally applied in experimental sessions while participants were judging the similarity of these pairs. The results of the experiment indicated that similarity ratings between two pages correlate negatively with the number of alterations made to the layout of one of the pages. Similarity ratings between two pages...
The experience of panic symptoms across racial groups in a student sample

While there is general agreement that, across cultures, panic disorder appears to be characterized by sudden onset of bodily sensations, such as dizziness and heart palpitations, followed by catastrophic misinterpretations of these symptoms, there remains a need for research investigating ethnic/cultural differences in the experience of panic attacks. In addition to investigating ethnic differences in the experience of panic, it is important to assess whether increased endorsement of panic symptoms translates into increased dysfunction. The present study investigated differences in the experience of panic attacks and examined the relation between symptom endorsement and overall distress and impairment in a large multiracial/ethnic student population. Preliminary analyses indicated that although overall endorsement of panic symptoms was similar across groups, differences did emerge on specific symptoms. Participants identifying as Asian tended to endorse symptoms such as dizziness, unsteadiness, choking, and feeling terrified more frequently than those identifying as Caucasian, and individuals identifying as African American reported feeling less nervous than those identifying as Caucasian. Participants of Hispanic/Latino(a) descent showed no differences from any other group on symptom endorsement. Panic symptom severity was not found to differ across racial/ethnic groups; however, the correlation between panic symptoms and panic severity was stronger for Asian and Caucasian participants than for African Americans. These results suggest that symptoms of panic may be experienced differently across racial/ethnic groups, and highlight the need for clinicians and researchers to assess panic symptoms within the context of culture.
Monomeric metal alkoxides and trialkyl siloxides: (BDI)Mg(OtBu)(THF) and (BDI)Zn(OSiPh3)(THF). Comments on single site catalysts for ring-opening polymerization of lactides

The monomeric alkoxide (BDI)Mg(OtBu)(THF) and triphenylsiloxide (BDI)Zn(OSiPh3)(THF) have been prepared and characterized and shown to reversibly dissociate THF in solution on the NMR time scale; both compounds are active precursors for the ring-opening polymerization of lactide and the rate of polymerization is notably faster for the magnesium complex though in the polymerization of rac-lactide only the zinc complex shows selectivity for heterotactic tetrads.
Cord Blood CD4+ T Lymphocytes Differentially Express CCR5 and CXCR4, HIV-1 Co-receptors † 1404

Cord Blood CD4+ T Lymphocytes Differentially Express CCR5 and CXCR4, HIV-1 Co-receptors † 1404
Combined effects of exchange and g -value anisotropy in the conduction-electron spin resonance of metals

A heuristic model is developed to explore the combined effects of exchange and $g$-value anisotropy in the conduction-electron spin resonance in polyvalent metals where it may be appropriate to consider the electrons in different Brillouin zones to be partially decoupled from one another. Within the framework of this model the resonance should show structure at low temperature, and the conventional analysis of resonance data, using the theory of Platzman and Wolff to obtain the exchange parameter ${B}_{0}$, can be substantially in error if the effects of $g$-value anisotropy are not properly accounted for. Some features of existing data for aluminum are discussed in the context of this model, and it is noted that spin-resonance results may be able to remove the current ambiguity in the sign of the pseudopotential matrix element ${V}_{111}$ used in calculations of the band structure of aluminum.
Attitude determination and control subsystem for the TOPEX satellite

The Ocean Topography Experiment satellite will carry a modular Attitude Determination and Control Subsystem (ADCS) which contains all equipment required for attitude determination, stabilization, and control, as well as hydrazine thruster firing control, during all mission phases. Attention is presently given to the ADCS's architecture, constituent hardware components, performance requirements, and predicted on-orbit performance compliance, with emphasis on the design and analysis of the Normal Mission Mode control algorithm furnishing the primary scientific data-acquisition operational mode. This mode's attitude determination and control of on-orbit performance is predicted to better than 43 arcsec.
Is the concept of central nervous system immune privilege irrelevant in the setting of acute infection

While historically viewed as an immune-privileged area fully isolated from the immune system, the central nervous system (CNS) is now appreciated to maintain dynamic bi-directional communication with the immune system across the blood–brain barrier (BBB) (1, 2). In no setting can this communication be more urgent that acute CNS infection – a dampened or delayed host response could allow an invading virus or bacterium to gain a foothold within the brain, while over-exuberant or protracted inflammation might cause substantial collateral damage to sensitive and non-renewable cells such as neurons. In this opinion piece, we compare host immunity against one prototype virus and one prototype bacterium known to cause disease either outside or within the CNS. Allowing for some variability in disease pathogenesis, and leaving aside complex issues related to chronic intrauterine or neonatal infections, we argue that antimicrobial host responses in both CNS and non-CNS tissue compartments of adult hosts who acquire these infections exhibit many more similarities than differences. In this setting, the concept of CNS immune privilege seems antiquated.
SU‐E‐T‐700: PMMC ‐ a High‐Performance Monte Carlo Code for Proton Beam Dose Calculation

Purpose: The proton macro Monte Carlo (PMMC) method uses a fast macro Monte Carlo radiation transport algorithm for high‐energy proton transport through an absorbing medium. Methods: PMMC uses results derived from traditional Monte Carlo simulations of proton transport through macroscopic cylinders of varying length, radii and material composition. These traditional Monte Carlo simulations are done for many incident proton energies and the results are used to transport protons through an absorber geometry in a step‐by‐step manner. The absorber geometry consists of a three‐dimensional (3D) density matrix that can represent objects like a water phantom or computed tomography data. The source is specified by the user in terms of gantry angle and beam characteristics like position, energy and size. During proton transport, energy lost by the protons during each step is scored in a 3D dose grid. The creation of secondary neutrons is tracked as well to allow for estimation of the neutron dose. Results: The algorithm, which was written in C++, is currently capable of simulating 1 million protons per minute. The accuracy of the PMMC simulations was assessed by comparing the results to simulations done with the same source parameters in MCNPX. The simulations consisted of monoenergetic pencil beams and Gaussian‐shaped beams directed onto a water phantom. In general, PMMC and MCNPX are in good agreement in the high‐energy proton region before the Bragg peak, differing by less than 3%. PMMC performs worse at the depth of maximum dose, differing by as much as 10%. Conclusions: Forthcoming modifications to PMMC will address the discrepancies in the Bragg peak region and further modifications are underway to allow PMMC to be used with absorbers that are heterogeneous in density and material composition.
Determinants of health care use by children in rural western North Carolina: results from the Mountain Accessibility Project.

Objective. To assess determinants of health care visits among children in a 12-county region of western North Carolina representative of rural areas in the United States. Methods. Households were randomly selected for surveys of household characteristics, health status, and health care use. Surveys were conducted June 1999 to January 2000 and were stratified for children younger than 5 years and 5 years and older. The number of health care visits in the year before the survey was used as the outcome measure. Weighted mean visits and associations of family demographic and child health variables with the number of visits were determined by ratio and multivariate survey regression methods. Results. Among children who lived in rural Appalachian regions of North Carolina in 1999, 90% had either public or private insurance coverage. The mean number of visits per child was 5.7 (median: 2.6), and in each age group the number of visits in the previous year exceeded the recommended number of well-child visits. There were no apparent geographic access barriers to care in this population, in that increased distances to provider sites did not result in declining numbers of visits. For children younger than 5 years, the primary determinants of health care use during the previous year were age, insurance status, and household income. Infants had more visits than older, preschool children, and those with household incomes >$40 000 per year had 76% more visits than those with incomes $40 000 per year were associated with 2.5-fold increased health care visits, and those with household incomes between $20 000 and $40 000 per year had 2-fold increased health care visits, compared with those with household incomes Conclusions. This rural population seems to have reasonably good access to care overall. The key determinants of health care use among these rural children were similar to those found in urban and other populations in the United States and likely are universal: health insurance coverage, household income, and parent perceptions of their child’s pain. As in other populations, programs in rural areas that strengthen health insurance coverage and reduce poverty will have a direct impact on child health. Differential use of health care among white and black children, especially those 5 years and older, merits additional explanation.
A role for nitric oxide in hydroxyurea-mediated fetal hemoglobin induction

Hydroxyurea is a newly approved therapeutic agent for the treatment of sickle-cell disease. Hydroxyurea reduces the number of painful crises in sickle-cell patients presumably by increasing the levels of fetal hemoglobin, which has a large solubilizing effect on sickle-cell hemoglobin and reduces polymerization (1). Despite being used to treat a number of cancers for nearly 30 years, the mechanism of how hydroxyurea increases fetal hemoglobin levels remains unclear. In this issue of the JCI, Cokic et al. present results that provide the first explanation of how hydroxyurea increases fetal hemoglobin levels (2). Specifically, they show that fetal hemoglobin increases in response to activation of soluble guanylyl cyclase (sGC) by hydroxyurea-derived NO. The importance of this work manifests itself in at least three ways: 1) the in vitro identification of some of the molecular species involved in fetal hemoglobin induction, 2) a further demonstration of a role for NO in the activity of hydroxyurea, and 3) the application of this work to the development of new NO based treatments for sickle-cell disease. The work described in this study (2) relies on the authors’ ability to recognize clues from previous basic and clinical research. First, hydroxyurea reacts with enzymes and proteins, particularly heme-containing proteins, to release NO (3–7). Other studies reveal that patients taking hydroxyurea demonstrate increased levels of nitrite, nitrate, and iron nitrosyl hemoglobin, all of which are markers for NO (8–10). Finally, sGC activators increase γ-globin gene expression in both eryth-roleukemic cells and primary human erythroblasts and sGC inhibitors prevent this increase (11). The combination of these results with the ability of NO to stimulate sGC led to the design and execution of the described experiment to determine the effect of nitric oxide donors and hydroxyurea on fetal hemoglobin induction.
N-methylmethionine at the amino terminus of a protein required for bacterial chemotaxis.

The methylation of glutamate residues during Chemotaxis has been extensively investigated in Escherichia coli and Salmonella typhimurium (see Stock and Simms, this volume). This reaction is thought to function to modulate the activities of receptor proteins located in the cytoplasmic membrane. Levels of glutamate methylation are controlled by the activities of specific enzymes: the CheR methyltransferase adds groups and the CheB methylesterase removes them. Although reversible methylation at glutamates provides an important adaptive function in chemosensing, it is not essential for Chemotaxis, and mutants completely deficient in both the CheR and CheB enzymes retain an ability to migrate towards favorable environmental conditions. Genetic studies indicate that four cytoplasmic proteins are essential for Chemotaxis, CheA, CheW, CheY, and CheZ (Table 1). These appear to provide a link between chemoreceptors in the membrane and the flagellar motor. One of these components, the CheZ protein, is methylated at its amino terminus (Stock et al., 1987c). Both in terms of its function and chemistry, CheZ methylation is quite different from the reversible methylation that occurs at glutamate residues in the receptors.
Evaluation of Esophageal Motor Function With High-resolution Manometry

For several decades esophageal manometry has been the test of choice to evaluate disorders of esophageal motor function. The recent introduction of high-resolution manometry for the study of esophageal motor function simplified performance of esophageal manometry, and revealed previously unidentified patterns of normal and abnormal esophageal motor function. Presentation of pressure data as color contour plots or esophageal pressure topography led to the development of new tools for analyzing and classifying esophageal motor patterns. The current standard and still developing approach to do this is the Chicago classification. While this methodical approach is improving our diagnosis of esophageal motor disorders, it currently does not address all motor abnormalities. We will explore the Chicago classification and disorders that it does not address.
Joint Immobilization of Plant Growth-Promoting Bacteria and Green Microalgae in Alginate Beads as an Experimental Model for Studying Plant-Bacterium Interactions

A simple, quantitative experimental model, offering a convenient and basic approach to studies of plant-bacterium interactions, is proposed. This involves immobilizing a unicellular, freshwater microalga, a Chlorella species, serving as the plant, with a plant growth-promoting bacterium, an Azospirillum species, in small alginate beads to allow close interaction and to avoid external interference from bacterial contaminants.
On the capacity region of the vector fading broadcast channel with no CSIT

We develop an upperbound on the capacity region of an isotropic fading vector broadcast channel in terms of the capacity region of a scalar fading broadcast channel. Using this upperbound we prove the optimality of the Alamouti scheme [1] in a broadcast setting and extend the recent results [2] on the capacity region of the fading scalar non-degraded broadcast channel to fading vector non-degraded broadcast channels. The upperbound is fundamental in that it makes no assumption regarding the distribution of the users' channel magnitudes, the distribution of the additive noise, or the amount of channel information available at the receiver. The scalar upperbound explicitly characterizes the loss of degrees of freedom in a vector broadcast channel when the transmitter has no information about the "direction" of the users' channel vectors.
Influence of Dietary Calcium on Phosphorus Absorption and Excretion and on Phosphorus-33 Distribution in Laying Hens

An experiment was conducted using isotope-dilution and comparative balance techniques to estimate urinary and fecal P excretion of laying hens fed different levels of dietary Ca. Two levels of dietary Ca (3.46 and 4.2%) were fed to eight hens for 30 days. After 30 days, 50 microCi of the radioisotope /sup 33/P was injected intramuscularly to label endogenous P. On the 2nd day after /sup 33/P dosing and at 1 h postoviposition, plasma, liver, kidney, femur bone, whole egg, ileum, ileal digesta, and excreta samples were collected from each hen. Results showed a favorable effect of increasing dietary Ca consumption (2.91 vs 3.57 g/hen per day): femur ash increased (P less than .08), excreta P decreased (P less than .03), and urinary P decreased (P less than .06). The P content of ileal digesta was not affected by dietary Ca intake, but excreta P was greater for hens consuming less Ca, indicating that, during the collection period, excretion of P in urine was increased by the low Ca diet. Endogenous P secretions constituted less than 1% of the P in ileal digesta and excreta samples and this proportion was not changed by dietary Ca consumed.
Altered Expression of SPINDLY Affects Gibberellin Response and Plant Development

Gibberellins (GAs) are plant hormones with diverse roles in plant growth and development. SPINDLY (SPY) is one of several genes identified in Arabidopsis that are involved in GA response and it is thought to encode an O-GlcNAc transferase. Genetic analysis suggests that SPY negatively regulates GA response. To test the hypothesis that SPY acts specifically as a negatively acting component of GA signal transduction, spy mutants and plants containing a 35S:SPY construct have been examined. A detailed investigation of the spy mutant phenotype suggests that SPY may play a role in plant development beyond its role in GA signaling. Consistent with this suggestion, the analysis of spy er plants suggests that the ERECTA (ER) gene, which has not been implicated as having a role in GA signaling, appears to enhance the non-GA spy mutant phenotypes. Arabidopsis plants containing a 35S:SPY construct possess reduced GA response at seed germination, but also possess phenotypes consistent with increased GA response, although not identical to spy mutants, during later vegetative and reproductive development. Based on these results, the hypothesis that SPY is specific for GA signaling is rejected. Instead, it is proposed that SPY is a negative regulator of GA response that has additional roles in plant development.
Predictors of educational attainment in the Chicago Longitudinal Study.

The authors investigated a comprehensive set of predictors of high school completion and years of completed education for youth in the Chicago Longitudinal Study, an ongoing investigation of over 1500 low-income, minority children who grew up on high-poverty neighborhoods. The study sample included 1286 youth for whom educational attainment could be determined by age 20. Predictors were measured from birth to high school from participant surveys and administrative records on educational and family experiences as well as demographic attributes. Results from regression analyses indicated that the model explained 30.4% of the variance in years of completed school. The model also predicted accurately 73.3% of youths’ observed high school completion status and 72.6% of their high school graduation status. The strongest predictors of educational attainment were maternal educational attainment, school absences and mobility, grade retention, and youth’s educational expectations. Findings indicate that students’ expectation and school mobility are targets of intervention that can promote children’s educational persistence.