cssi/SciSciGPT-SciSciNet huggingface dataset:
Disruption of ideal geometry in the growth of receptaculitids: a natural experiment in theoretical morphology

Facets of the Silurian receptaculitid Ischadites barrandei are arranged in circlets about a nucleus. They form a set of spirals, originally eight in number, but increasing by the intercalation of new facets (initiating new spirals) in later circlets. We have simulated the surficial geometry of this alga by assuming, as much evidence indicates, that facets are limited in final size and that new spirals must therefore be intercalated in order to cover the surface with a fully tesselated pattern. We use only five parameters in our simulation: nature of the surface (radius of a sphere), tightness of the spirals (assumed to be logarithmic) and rate of increase in facet width (three parameters of an equation fitted to actual data). The program draws facets in circlets and intercalates new ones whenever the sum of facet diameters is at least a facet less than the circumference of the circlet. By holding all but one parameter constant, we can test the influence of single factors upon the pattern of intercalation. We compare these figures with actual patterns of intercalation for eight specimens. Variation in tightness of the spiral seems to affect the pattern most radically—tight spirals intercalate fewer facets because new circlets stay near the pole of the sphere. The morphology of intercalation supports the interpretation of Rietschel (1969, contra Nitecki, 1972 and Byrnes, 1968) that the nuclear circlets are the oldest part of the plant and that new circlets are generated at the opposite pole. Our simulation represents a basic pattern in nature, not a specific feature of receptaculitids. All structures that fill space with spirals and impose limits upon the size of individual units must add new spirals. Bryozoans subject to similar constraints but growing in a completely different way (peripheral growth in radial rows) display the same final pattern.
Biogenesis of silk fibroin mRNA: an example of very rapid processing?

Publisher Summary This chapter reviews that an affinity column containing a bound synthetic polynucleotide has been used as a tool for the isolation of pulse-labeled fibroin mRNA. Two passages through the column are sufficient to purify the pulse-labeled fibroin gene transcripts from the total hnRNA population. The fibroin mRNA molecules isolated after pulse-labeling in vivo are not demonstrably larger than fibroin mRNA. In fact, for short pulse-labeling times the peak of the gel profile of pulse-labeled mRNA is at a position one to two gel slices smaller than mature mRNA. To investigate the possibility that putative RNA processing cuts may be occurring even before the termination of transcription, experiments have been done under conditions in which processing may be expected to be slower. In vivo pulse-labeling of animals at 11.5°C, followed by affinity chromatography and gel electrophoresis, results in a different size-profile of newly synthesized fibroin mRNA. In this case, the peak of the size distribution is a few gel slices larger than the mature mRNA peak. This larger material, which accumulates at low temperature, could represent a very short-lived precursor species, and may in fact be the “primary” transcript of the silk fibroin gene.
Temporal Resolution of Ensemble Visual Motion Signals in Primate Retina

Recent studies have examined the temporal precision of spiking in visual system neurons, but less is known about the time scale that is relevant for behaviorally important visual computations. We examined how spatiotemporal patterns of spikes in ensembles of primate retinal ganglion cells convey information about visual motion to the brain. The direction of motion of a bar was estimated by comparing the timing of responses in ensembles of parasol (magnocellular-projecting) retinal ganglion cells recorded simultaneously, using a cross-correlation approach similar to standard models of motion sensing. To identify the temporal resolution of motion signals, spike trains were low-pass filtered before estimating the direction of motion. The filter time constant that resulted in most accurate motion sensing was in the range of 10-50 msec for a range of stimulus speeds and contrasts and approached a lower limit of ∼10 msec at high speeds and contrasts. This time constant was, on average, comparable to the length of interspike intervals. These findings suggest that cortical neurons could filter their inputs on a time scale of tens of milliseconds, rather than relying on the precise times of individual input spikes, to sense motion most reliably.
The s-Process Elements Cadmium and Tin

The data used for this study were high signal-to-noise absorption spectra of the Cd II 2145 A and Sn II 1400 A transitions observed with the HST’s Goddard High Resolution Spectrograph.
Percutaneous occlusion of the left subclavian and celiac arteries before or during endograft repair of thoracic and thoracoabdominal aortic aneurysms with detachable nitinol vascular plugs

Purpose To review an experience with the Amplatzer vascular plug (AVP) for prevention of type II endoleaks during endovascular aneurysm repair (EVAR) of thoracic and thoracoabdominal aneurysms. Materials and Methods Retrospective review was undertaken of 14 patients undergoing transcatheter occlusion of the left subclavian ( n = 12) or celiac artery ( n = 2) with the AVP as part of EVAR of thoracic and thoracoabdominal aneurysms at a single institution. Procedural criteria evaluated were success at target vessel occlusion, the number of AVPs used, use of adjunctive embolization devices, and embolization-related ischemic end-organ events. Follow-up imaging criteria included evaluation of persistent target vessel occlusion, evidence of device migration, and the presence and characterization of endoleak secondary to AVP failure. Results Complete target vessel occlusion was documented for all cases. In six cases, more than one AVP was placed, with an average of 1.5 devices per patient. In two cases, adjunctive coils were placed. Computed tomographic or magnetic resonance angiography follow-up was available for all patients (mean follow-up, 419 days; range 28–930 d). No case showed evidence of device migration or type II endoleak resulting from AVP failure. There was a single instance of left subclavian artery recanalization without type II endoleak. There were no embolization-related ischemic end-organ events. Conclusions Transcatheter arterial occlusion of the subclavian and celiac arteries with the AVP is a valuable adjunct to endografting in cases in which side branch embolization is necessary to extend the landing zone.
The cells of Boettcher in the bat, Pteronotus p. parnellii

Abstract The structural characteristics, distribution and intercellular relationships of the cells of Boettcher were studied in the mustache bat, Pteronotus p. parnellii . The cells of Boettcher have many structural features similar to those described in other mammals, but in Pteronotus they are distributed throughout the cochlea and are associated with relatively large amounts of secretory and/or absorptive material. Much of this material seems to be derived from or contribute to, a darkly staining upper layer of the basilar membrane. This material accumulates in elaborate microvillus-filled intercellular channels which are restricted to an area near the basilar membrane. The channels communicate with the basilar membrane surface through wide intercellular spaces and through small canals. The microvillus-filled channels are confluent with large extracellular spaces between Boettcher's cells and a single row of cells which form the floor of the outer tunnel. The latter have irregular shaped nuclei, contain many vacuoles and like Boettcher's cells, are associated with large amounts of basilar membrane-like material. Observations on Pteronotus , as well as other species of bats, do not support concepts relating Boettcher's cells to hair cell innervation patterns or to high frequency hearing.
Fuzzy expectation and energy states in fuzzy media

Abstract This paper is concerned with energy levels and the density of states in fuzzy crystals. The determination of eigenvalue spectrum, or the density of states, for a particle in a fuzzy crystal, is obtained by using the concepts developed in fuzzy statistics. Various analytical results are found, using the fuzzy expectation; these results can be applied to a variety of fields such as decision making under uncertainty, pattern analysis, and quantum mechanics.
Some physical properties of three dental porcelains

T HE ESTHETIC REQUIREMENTS OF modern dentistry demand the use of materials which imitate natural tooth enamel. For this purpose, the highly vitreous dental porcelains equal or, in most cases? excel other restorative materials of today. Although the properties of porcelain require very exacting techniques to meet modern standards, leading clinicians have gradually developed ceramics into an important branch of restorative dentistry. Their methods of fabricating dental restorations which resemble living tooth structure are unique among ceramic practices.’ Since the properties of dental porcelains influence the fabrication of prjrcelain restorations, knowledge of these porcelains is important to the practicing dentist for developing new techniques in dental ceramics.
Defragmentation of Resources in Virtual Desktop Clouds for Cost-Aware Utility-Optimal Allocation

Cloud Service Providers (CSPs) make virtual desktop cloud (VDC) resource provisioning decisions within desktop pools based on user groups and their application profiles. Such provisioning is aimed to satisfy acceptable user quality of experience (QoE) levels and is coupled with subsequent placement of VDs across distributed data centers. The placement decisions are influenced by session latency, load balancing and operation cost constraints. In this paper, we identify the resource fragmentation problem that occurs when placement is done opportunistically to minimize provisioning time and deliver satisfactory user QoE. To solve this problem, which inherently is an NP-Hard problem, we propose a defragmentation scheme that has fast convergence time and has three levels of complexity: (i) "utility fair provisioning" (UFP) to optimize resource provisioning within a data center - to achieve relative fairness between desktop pools, (ii) "static migration-free utility optimal placement and provisioning" (MUPP) to optimize resource provisioning between multiple data centers - to improve performance, and (iii) "dynamic global utility optimal placement and provisioning" (GUPP) to optimize resource provisioning using cost-aware and utility-maximal VD re-allocations and migrations - to increase scalability. We evaluate our defragmentation scheme against 'least latency', 'least load', and 'least cost' schemes using a novel "VDC-Sim" simulator that we have developed in this study. Our simulations leverage profiles of user groups and their applications within desktop pools, obtained from a real VDC test bed. Our simulation results demonstrate that defragmentation is an important optimization step that can enable CSPs to achieve fairness, substantially improve user QoE and increase VDC scalability.
Reporting the Results of Statewide Assessment.

ABSTRACT Reporting the results of statewide a sessment looms as a problem as More states pass from the planning to plementation phase in their assessment programs. When energies are fo sed on the purpose of the a sessment, formulating objectives, and inst ment construction, reporting takes a back seat because it happens last. There are some general principles to be followed-in order to report effectively the results of a large scale assessment program. This paper begins with several ,recent references on how to report the results of large scale assessment programs. The remainder of this paper is intended to provide specific new thoughts for implementation of old principles. The ultimate success of state assessment programs will depend on how well assessment results are reported to their various audiences. In this paper, the most compelling recommendations for improving reporting practices areplan ahead, develop different, reports for different audiences, and field test report formats to determine the language and content that, are most meaningful to respective audiences. Reporting should receive the same careful attention as instrument itonstruction with sufficient opportunity for feedback from intended users. (Author/DEP)
An efficient Associative Processor solution to an Air Traffic Control problem

This paper proposes a SIMD solution to air traffic control (ATC) using an enhanced SIMD machine model called an Associative Processor (AP). This differs from previous ATC systems that are designed for MIMD computers and have a great deal of difficulty meeting the predictability requirements for ATC, which are critical for meeting the strict certification standards required for safety critical software components. The proposed SIMD solution will support accurate and meaningful predictions of worst case execution times and will guarantee all deadlines are met. Also, the software will be much simpler and smaller in size than the current corresponding ATC software. An important consequence of these features is that the V&V (Validation and Verification) process will be considerably simpler than for current ATC software. Additionally, the associative processor is enhanced SIMD hardware and is considerably cheaper and simpler than the MIMD hardware currently used to support ATC. The ClearSpeed CSX600 accelerator is used to emulate the AP model. A preliminary implementation of the proposed method has been developed and experimental results comparing MIMD and CSX600 approaches are presented. The performance of CSX600 has better scalability, efficiency, and predictability than that of MIMD.
Flies and humans share a motion estimation strategy that exploits natural scene statistics

Sighted animals extract motion information from visual scenes by processing spatiotemporal patterns of light falling on the retina. The dominant models for motion estimation exploit intensity correlations only between pairs of points in space and time. Moving natural scenes, however, contain more complex correlations. Here we show that fly and human visual systems encode the combined direction and contrast polarity of moving edges using triple correlations that enhance motion estimation in natural environments. Both species extract triple correlations with neural substrates tuned for light or dark edges, and sensitivity to specific triple correlations is retained even as light and dark edge motion signals are combined. Thus, both species separately process light and dark image contrasts to capture motion signatures that can improve estimation accuracy. This striking convergence argues that statistical structures in natural scenes have profoundly affected visual processing, driving a common computational strategy over 500 million years of evolution.
Feminists in Power: Women Cabinet Ministers in the New Democratic Party (NDP) Government of Ontario, 1990–1995

The difference between quantitative representation and qualitative (or “substantive”) representation has become of interest to scholars exploring the impact of the number of women elected to political institutions. Where once the focus was on the number alone, the most recent work emphasizes the significance of “interest representation.” Ultimately, the question is: Does it make a difference to have substantive representation of women, especially in positions of power? Does it make a difference in terms of policy outcomes? Does it make a difference in terms of institutional change? This research examines a case study of women cabinet ministers in the New Democratic Party government of Ontario, Canada, from 1990 to 1995. Based on lengthy interviews and an analysis of policy outcomes, this paper concludes that it did indeed make a difference, on both fronts, but that those transformations were not as dramatic as the feminist progressive components might project nor as extensive as the women's movement had hoped.
Vacuum Rabi Splitting and Intra-Cavity Dark State in a Cavity-Atoms System

We report an experimental study of a cavity-atom composite system and observation of the intracavity dark state and the multi-atom vacuum Rabi splitting.
Limitations on the use of the pulsed-wire field measuring technique☆

Abstract As wigglers become longer and the wavelength of the light they produce becomes shorter, the requirements for magnetic field uniformity and precision of wiggler construction become more severe. Techniques used to measure magnetic fields and to estimate the performance of wigglers are now being pushed to their limits in precision and are generally awkward and time consuming in practice. A new field-error measurement technique has been developed that has the usual advantages of a null technique, demonstrates high sensitivity to field errors, and is rapid and simple to employ. With this technique, it appears practical to use computer control to both measure and correct field errors. In a particularly attractive application, these measuring and correcting steps could be carried out on a daily basis for an operational wiggler, which is mounted under vacuum in its optical cavity. In this way, changes in the fields caused by aging or by thermal or radiation-induced deterioration effects could be rapidly identified and corrections could be instituted without significant interruption to normal operations. The principles and limitations of this technique will be described and examples given of various implementations that have been examined experimentally.
The distribution of carotid endarterectomy procedures among surgeons and hospitals in New York state: Is regionalization of specialized vascular care occurring?

Abstract Introduction: In a published analysis of all carotid endarterectomies (CEAs) performed in New York state from 1990 to 1995, perioperative mortality rate was inversely correlated with surgeon and hospital CEA volume, was significantly higher when CEAs were performed by surgeons who performed less than five CEAs annually, and was significantly lower in hospitals where surgeons performed more than 100 CEAs annually. The purpose of this study was to determine whether this information has influenced practice patterns in New York state. Methods: The database of the Center for Medical Consumers was queried to determine the volume distribution among surgeons and hospitals of all CEAs performed in New York state in 1999 and 2000. Results: During 1999, 695 surgeons in 169 hospitals performed 9458 CEAs (mean, 13.6 per surgeon). Three hundred fifty-three surgeons (51%) performed less than five CEAs, and 180 (26%) performed only one CEA during the year. Only 41 surgeons (6%) performed more than 50 CEAs. Likewise, in only 28 of the hospitals (17%) were more than 100 CEAs performed during 1999, whereas in 73 of the hospitals (43%) 20 or less CEAs were carried out during the year. During 2000, 684 surgeons performed 8196 CEAs in 165 hospitals. Three hundred fifty-three (52%) performed less than five CEAs, and 229 (33%) performed only one CEA during the year. Only 33 surgeons (5%) performed more than 50 CEAs during 2000. In only 26 hospitals (16%) were more than 100 CEAs performed during 2000, whereas in 71 hospitals (43%) 20 or less CEAs were carried out. Conclusion: It appears that published compelling evidence that operator and institutional volume influence outcome has not influenced referral patterns or lead to a regionalization of CEA care in New York state. Robust educational programs directed to patients and referring physicians appear indicated. (J Vasc Surg 2002;36:1146-53.)
End-of-life care for neonates and infants: the experience and effects of a palliative care consultation service.

Objective. Neonates and infants have the highest death rate in the pediatric population, yet there is a paucity of data about their end-of-life care and whether a palliative care service can have an impact on that care. The objective of this study was to describe end-of-life care for infants, including analysis of palliative care consultations conducted in this population. We hypothesized that the palliative care consultations performed had an impact on the infants9 end-of-life care. Design. A retrospective chart review using the “End of Life Chart Review” from the Center to Improve Care for the Dying was conducted. The participants were the patients at Children9s Hospital of Wisconsin who died at Results. Among the 196 deaths during the study period, 25 (13%) of these infants and families had palliative care consultations. The rate of consultations increased from 5% of the infant deaths in 1994 to 38% of the infant deaths in 1997. Infants of families that received consultations had fewer days in intensive care units, blood draws, central lines, feeding tubes, vasopressor and paralytic drug use, mechanical ventilation, cardiopulmonary resuscitation, and x-rays, and the families had more frequent referrals for chaplains and social services than families that did not have palliative care consultations. Conclusions. This study describes the end-of-life care that infants and their families received. Fewer medical procedures were performed, and more supportive services were provided to infants and families that had a palliative care consultation. This suggests that palliative care consultation may enhance end-of-life care for newborns.
Cyclodextrin dimers as cleavable carriers of photodynamic sensitizers.

Several phthalocyanines carrying hydrophobic components have been synthesized and shown to bind to a group of cyclodextrin dimers with a carbon−carbon double bond in the linker. The complexes are soluble in water. On irradiation in the presence of oxygen, the singlet oxygen produced cleaves the olefinic linkers in the complexes, resulting in precipitation of the sensitizers. This process concentrates the sensitizers in the light beam, a process that has useful potential in photodynamic therapy.
Computer simulation of photochemically induced electron transfer

Abstract We have simulated by molecular dynamics the solvent relaxation immediately after photoinduced electron transfer of an aqueous ferric-ferrous system. The simulations show that the process occurs in a subpicosecond time scale and in a fashion qualitatively consistent with Marcus' model.
Cerebrospinal leukemoid reaction secondary to VZV meninigoencephalitis in an AML patient post allogeneic bone marrow transplantation

To the editor: Leukemoid reaction (white blood cells [WBCs] >50 000/μL) secondary to inflammatory or neoplastic process describes elevated WBC counts in the peripheral blood (PB).[1][1] To our knowledge, there has only been 1 case report of a leukemoid reaction in the cerebrospinal fluid (CSF)
Vertex operators for axionic wormholes

Abstract The long distance effect of a small wormhole on correlation functions can be summarized as the insertion of a local “vertex” operator. We compute, to leading order in the size of the wormhole and in Planck's constant, the vertex operator for axionic wormholes. The effects of matter fields, primarily in the form of conformally coupled scalars, are also studied. The effective bilocal action does not seem to factorize, clouding the notion of a local vertex operator.
Human medial temporal lobe potentials evoked in memory and language tasks

Abstract Lesion evidence indicates that the human medial temporal lobe (MTL) makes an important contribution to Recent Memory formation and retrieval very soon after a stimulus item is encountered. For verbal materials, this contribution is lateralized to the language dominant hemisphere. Evoked potentials recorded from the MTL during verbal recognition memory display two late endogenous components. Both show differences between repeated target words and non-repeated distractor words. The first component is usually negative and has an average latency of 460 msec. It is also observed in lexical decision and picture naming tasks. This component is similar in latency, morphology, and task correlates to the scalp-recorded N4 potential. This ‘MTL-N4’ is smaller in amplitude to words recognized as repeats and is largest in amplitude in the left MTL. The second component is usually positive and has an average latency of 620 msec. It is similar in morphology and MTL topography to the P3-like component evoked at 360 msec to rare tones in auditory discrimination tasks. This ‘MTL-P3’ is larger in amplitude to words recognized as repeats. Both components are of very large amplitude and invert polarity over short distances within the MTL. Hence, they appear to be locally generated in the MTL. The extent to which volume conduction of these MTL potentials contribute to scalp-recorded EPs is unclear. The MTL-N4 might be involved with memory formation and retrieval processes, and the MTL-P3 might index completion of the detection-recognition cycle.
A social community based approach for reducing the propagation of infectious diseases in healthcare

In this work, we investigate the feasibility and effectiveness of using human contact traces collected from mobile phones to derive social community information to reduce the disease propagation rate in the healthcare domain. Our trace-driven simulation results showed that our scheme is highly effective, and thus opens more opportunities for utilizing social relationships information to support healthcare related applications.
Explaining political trust among African Americans: Examining demographic, media, and social capital and social networks effects

Abstract African Americans routinely have lower levels of political trust compared with whites. Explanations of their political trust remain rather unexamined. Using data taken from the 1996 National Black Election Study, this analysis examines three models to test how demographic characteristics, the media, and social capital and social networks influence political trust among African Americans. The results show modest support for the models. However, social location as measured by demographic characteristics is most important for explaining the political trust of African Americans.
Prediction, events, and the advantage of agents: the processing of semantic roles in visual narrative.

Agents consistently appear prior to Patients in sentences, manual signs, and drawings, and Agents are responded to faster when presented in visual depictions of events. We hypothesized that this ‘‘Agent advantage’’ reflects Agents’ role in event structure. We investigated this question by manipulating the depictions of Agents and Patients in preparatory actions in wordless visual narratives. We found that Agents elicited a greater degree of predictions regarding upcoming events than Patients, that Agents are viewed longer than Patients, independent of serial order, and that visual depictions of actions are processed more quickly following the presentation of an Agent vs. a Patient. Taken together these findings support the notion that Agents initiate the building of event representation. We suggest that Agent First orders facilitate the interpretation of events as they unfold and that the saliency of Agents within visual representations of events is driven by anticipation of upcoming events.
Controversies Regarding Mammography, Breast Self-Examination, and Clinical Breast Examination

The number of women diagnosed with breast cancer continues to increase, but mortality rates have substantially declined. Much of the credit for this decline has been attributed to early detection from mammographic screening. However, there are significant controversies about the effectiveness of all screening tools for breast cancer, concerns about the potential harm that can result from screening, and questions about the appropriateness of screening recommendations. One of the greatest barriers to achieving consensus is the lack of agreement about the purpose of screening efforts. This article reviews many of the current controversies and attempts to clarify the arguments.
The Economic Design of X Charts Used to Maintain Current Control of a Process

Abstract This paper establishes a criterion that measures approximately the average net income of a process under surveillance of an X chart when the process is subject to random shifts in the process mean. The quality control rule assumed is that an assignable cause is looked for whenever a point falls outside the control limits. The criterion is for the case in which it is assumed that the process is not shut down while the search for the assignable cause is in progress, nor is the cost of adjustment or repair and the cost of bringing the process back into a state of control after the assignable cause is discovered charged to the control chart program. The paper shows how to determine the sample size, the interval between samples, and the control limits that will yield approximately maximum average net income. Numerical examples of optimum design are studied to see how variation in the various risk and cost factors affects the optimum. * The writer is greatly indebted to I. R. Savage and G. Greggory of ...
Effect of gepirone on increases in tryptophan hydroxylase in response to sound stress

Abstract Pretreatment (15 min) of male rats with gepirone given parenterlly (10 mg/kg i.p.) or intracranially into the dorsal raphe nucleus (14 or 21 μg) blocks the rapidly reversible increase in brain tryptophan hydroxylase activity and 5-hydroxyindolamine acetic acid tissue levels seen in vitro after 1-h acute sound stress. Chronic gepirone treatment over 28 days (40 mg/day s.c.) prevents the stable enzyme activity increase induced by repeated sessions of sound stress, and the rapidly reversible increase always observed following sound stress. The gepirone metabolite, 1-(2-pyrmidinyl)-1-piperazine, is inactive in each of these experiments. Transient blood pressure elevations occur with each sound presentation, but no persistent hypertension is observed with repeated sound-stress exposures. Gepirone may block the sound stress-induced biochemical increases by its inhibition of serotonergic neuronal firing in the dorsal raphe nucleus that is mediated by its agonist action at the somatodendritic (5-HT 1A ) autoreceptors.
Intravenous methylene blue as an aid to intraoperative localization and removal of the adrenal glands during laparoscopic adrenalectomy.

Abstract Background We hypothesized that intravenous methylene blue will facilitate adrenal gland identification and resection during laparoscopic adrenalectomy. Methods Five mini-Hanford pigs were anesthetized and monitored per an approved Internal Review Board protocol. Timing of color changes in the adrenals was recorded after administering methylene blue at three different doses: 2.5 mg/kg, 5.0 mg/kg, and 7.5 mg/kg. The time required for laparoscopic adrenalectomy with and without methylene blue was recorded. Results No color change occurred after the 2.5 mg/kg dose. For the 7.5 mg/kg versus the 5.0 mg/kg dose there was a more rapid bluish color change (mean time, 1.89 minutes versus 3.45 minutes; P = 0.03) and a longer duration of bluish color change (mean time, 12.20 minutes versus 6.19 minutes; P = 0.01). Laparoscopic adrenalectomy using methylene blue resulted in a 34.5% faster median resection time (10.13 minutes versus 15.47 minutes). Conclusions Methylene blue concentrates in the adrenal glands and facilitates identification and resection of the adrenal glands by a laparoscopic approach.
The squeezogram; an objective method for recording the course of chorea.

Summary A simple graphic method for recording the severity of choreiform movements is described. This permits a more exact evaluation of therapeutic agents than has heretofore been possible.
Single-pulse degenerate-cross-phase modulation in a single-mode optical fiber

Using a single ultrashort optical pulse propagating through a short nonbirefringent single-mode optical fiber, we have observed degenerate-cross-phase modulation of the two orthogonal circularly polarized components of the pulse. The spectral broadening of the two polarization components in the single laser pulse is attributed to self-phase modulation (SPM), degenerate-cross-phase modulation (DXPM), and interference between SPM and DXPM.
Residues in the seventh membrane-spanning segment of the dopamine D2 receptor accessible in the binding-site crevice.

The binding site of the dopamine D2 receptor, like that of other homologous G-protein-coupled receptors, is contained within a water-accessible crevice formed among its seven membrane-spanning segments. Using the substituted-cysteine accessibility method, we previously mapped the residues that form the surface of the binding-site crevice in the third and fifth membrane-spanning segments (M3 and M5). We have now mutated to cysteine, one at a time, 26 consecutive residues in and flanking the seventh membrane-spanning segment (M7) and expressed the mutant receptors in HEK 293 cells. Nine of these mutants reacted with charged, hydrophilic, lipophobic, sulfhydryl-specific reagents, added extracellularly, and were protected from reaction by a reversible dopamine antagonist, sulpiride. Thus, we infer that the side chains of these residues are in the water-accessible surface of the binding-site crevice. The pattern of accessibility of the cysteine-substitution mutants is consistent with M7 being a kinked α-helix.
Comparison of Gold Versus Platinum Electrodes on Myocardial Lesion Size Using Radiofrequency Energy

During radiofrequency (RF) catheter ablation of arrhythmias, temperatures that approach 100 degrees C cause a coagulum to form on the ablation electrode that results in an increase in electrical impedance and prevents further energy delivery. Since gold has nearly four times the thermal conductivity as platinum, the metal commonly used, it was postulated that gold tip electrodes could deliver more power and produce deeper lesions because of its greater heat dissipation from the electrode-tissue interface to the circulating blood. To test this hypothesis, RF energy was applied to fresh bovine ventricular myocardium using 6 French catheters with 2-mm long distal electrodes made from gold or platinum. Similar studies were also conducted using 7 French catheters with 4-mm long distal electrodes. Maximum lesion depth was defined as that produced with the level of energy just below that causing an impedance rise. A maximum lesion depth of 6.2 +/- 0.7 mm (mean +/- SD) was obtained with the gold 2-mm electrode and 4.7 +/- 0.5 mm with the platinum electrode (P = 0.003). The 4-mm gold electrode produced a maximum lesion depth of 7.2 +/- 1.4 mm, while a catheter with a 4-mm platinum electrode caused a maximum lesion depth of 5.8 +/- 0.7 mm (P = 0.05). We conclude that deeper lesions should be able to be made when RF energy is delivered to a gold rather than platinum tip electrode.
Influence of temperature on virulence of race 3 strains ofPseudomonas solanacearum

El marchitamiento de la papa causado por cepas de la raza 3 dePseudomonas solanacearum puede ser un problema serio a temperaturas medias relativamente bajas, como las que predominan en las regiones productoras de papa de Colombia y Peru. Como la raza 3 existe en regiones geograficas sumamente diversas, el proposito de este trabajo fue el de determinar si hay cepas de la bacteria que se han adaptado especificamente para causar marchitamiento a temperaturas bajas. Plantas de la variedad Russet Burbank fueron inoculadas con ocho cepas de la raza 3 y luego fueron mantenidas en fitotrones a 16, 20, 24, y 28°C por 15 dias. A la temperatura mas baja (16°C) solamente una cepa (S206) causo marchitamiento; la cepa S206 fue mucho mas virulenta a 16 y 20°C que cualquiera de las otras cepas. A 28°C., por otro lado, no hubo diferencia en la virulencia de las diferentes cepas; todas causaron marchitamiento completo a los 15 dis. Estos resultados fueron confirmados en un segundo experimento en el cual se usaron 10 cepas, cinco de la raza 1 y cinco de la raza 3. Solamente dos cepas (S206 y 257) causaron marchitamiento a las temperaturas mas bajas; a 28°C todas las cepas fueron igualmente virulentas. Las diferencias en virulencia no estuvieron correlacionadas con la tasa de crecimiento de las cepas en un medio liquido a 16°C. Algunas cepas tuvieron un aumento de poblacion similar al de las cepas S206 y 257in vitro, pero no causaron sintomasin planta a esta temperatura.
Targeting SDF-1/CXCL12 with a ligand that prevents activation of CXCR4 through structure-based drug design.

CXCL12 is an attractive target for clinical therapy because of its involvement in autoimmune diseases, cancer growth, metastasis, and neovascularization. Tyrosine sulfation at three positions in the CXCR4 N-terminus is crucial for specific, high-affinity CXCL12 binding. An NMR structure of the complex between the CXCL12 dimer and a sulfotyrosine-containing CXCR4 fragment enabled high-throughput in silico screening for inhibitors of the chemokine−receptor interface. A total of 1.4 million compounds from the ZINC database were docked into a cleft on the CXCL12 surface normally occupied by sulfotyrosine 21 (sY21), and five were selected for experimental screening. NMR titrations with CXCL12 revealed that four of the compounds occupy the sY21 site, one of which binds with a Kd of 64 μM. This compound selectively inhibits SDF1-induced CXCR4 signaling in THP1 cells. Our results suggest that sulfotyrosine recognition sites can be targeted for the development of novel chemokine inhibitors.
Zirconia-calcium phosphate composites for bone replacement

Abstract Bioceramic composites utilizing the good mechanical properties of ZrO 2 and the biocompatibility of calcium phosphate have been developed. Sintered samples containing various proportions of yttria-stabilized zirconia and calcium phosphate powders have been produced. Optical and scanning electron microscopic techniques have been used to characterize the microstructural features. Diametral compression strengths of composites have been measured after various treatment times in Ringer's solution. The data indicate that the strength and toughness of calcium phosphates used in clinical applications may be improved through the addition of zirconia particles.
IR and NMR studies of parasubstituted phenyltin compounds

Abstract Tetrakis- para substituted phenyltin compounds as well as the 1:1 addition complexes formed between tris- para substituted phenyltin chlorides and the Lewis bases, acetone, diethyl ether, dimethyl sulfoxide and N,N-dimethylacetamide, have been investigated by infrared and nmr spectroscopy. The results provide further evidence that in aryltin compounds dπ-pπ bonding exists between the empty d orbitals of the tin atom and the pi electrons of the phenyl ring. The results also indicate that substitution on the tin atom by a chlorine atom tends to enhance dπ-pπ bonding while substitution on the aromatic ring at the para position has little or no effect on the tinphenyl bond.
Gammaherpesvirus-Induced Lung Pathology Is Altered in the Absence of Macrophages

The purpose of this study was to examine the lung pathogenesis of murine gammaherpesvirus (MHV-68) infection in mice that lack CC chemokine receptor CCR2, an important receptor for macrophage recruitment to sites of inflammation. BALB/c and CCR2−/− mice were inoculated intranasally (i.n.) with MHV-68 and samples were collected during acute infection (6 dpi) and following viral clearance (12 dpi). Immunohistochemistry was used to determine which cells types responded to MHV-68 infection in the lungs. Lung pathology in infected BALB/c mice was characterized by a mixed inflammatory cell infiltrate, necrosis, and increased alveolar macrophages by 12 dpi. Immunohistochemistry showed intense positive staining for macrophages. CCR2−/− mice showed greater inflammation in the lungs at 12 dpi than did BALB/c mice, with more necrosis and diffuse neutrophil infiltrates in the alveoli. Immunohistochemistry demonstrated much less macrophage infiltration in the CCR2−/− mice than in the BALB/c mice. These studies show that CCR2 is involved in macrophage recruitment in response to MHV-68 infection and illustrates how impairments in macrophage function affect the normal inflammatory response to this viral infection.
Growth of single crystal GaN on a Si substrate using oxidized AlAs as an intermediate layer

Abstract We demonstrate that single-crystal hexagonal GaN can be grown by metal-organic chemical vapor deposition on an aluminum oxide compound (AlO x ) layer utilized as an intermediate layer between GaN and a Si(1 1 1) substrate. The surface morphology of GaN grown on the AlO x /Si(1 1 1) substrate is found to be very sensitive to both the GaN buffer-layer thickness and the AlO x thickness. Contact mode atomic force microscopy (C-AFM) observation indicates that the AlO x surface is composed of domain-like features with varying surface heights. A possible clue for a mechanism by which single crystal GaN grows on AlO x is discussed by comparing the domain-like surface features observed by C-AFM.
The structure of the Homunculus. II. Modeling the physical conditions in η Carinae's molecular shell

We present models that reproduce the observed double-shell structure of the Homunculus Nebula aroundCarinae, including the stratification of infrared H2 and (Fe ii) emission seen in data obtained with the Phoenix spectrograph on GeminiSouth,aswellasthecorrespondingstratifiedgraintemperatureseeninthermal-infrareddata.Tuningthemodel to match the observed shell thickness allows us to determine the threshold density that permits survival of H2 .A n average density of nH ' (0:5Y1) ; 10 7 cm � 3 in the outer zone is required to allow H2 to exist at all latitudes in the nebula,andforFe + torecombinetoFe 0 .ThisgivesindependentconfirmationoftheverylargemassoftheHomunculus, indicating a total of roughly 15Y35 M� (although we note reasons why the lower end of this range is favored). At the interfacebetweentheatomicandmolecularzones,wepredictasharpdropinthedusttemperature,inagreementwiththe bimodal dust color temperatures observed in the two zones. In the outer molecular shell, the dust temperature drops to nearlytheblackbodytemperature,andbecomesindependentofgrainsizebecauseofself-shieldingatshorterUVwave- lengths and increased heating at longer wavelengths. This relaxes constraints on large grain sizes suggested by near- blackbody color temperatures. Finally, from the strength of infrared (Fe ii) emission in the inner shell we find that the gas-phaseFeabundanceisroughlysolar.Thisisastonishinginsuchadustyobject,whereonenormallyexpectsgaseous iron to be depleted by 2 orders of magnitude. Subject headingg circumstellar matter — dust, extinction — ISM: individual (Homunculus nebula) — stars: individual (� Carinae) — stars: winds, outflows
A study of sociocultural factors related to voluntary blood donation in the Americas

OBJETIVO: Obtener informacion de base sobre los conocimientos, actitudes y practicas relacionados con la donacion voluntaria de sangre, asi como la capacidad instalada de los bancos de sangre para la atencion de donantes. METODOS: El estudio se realizo en 15 paises de la Region: Argentina, Bolivia, Colombia, Costa Rica, Cuba, Ecuador, El Salvador, Guatemala, Jamaica, Nicaragua, Panama, Paraguay, Peru, Republica Dominicana y Venezuela, con la cooperacion tecnica de la Organizacion Panamericana de la Salud, oficina regional de la Organizacion Mundial de la Salud. Se utilizo una metodologia formativa cualitativa mediante entrevistas a donantes, publico en general y personal de salud, asi como observacion directa, grupos focales, pruebas de conocimientos y revision documental. RESULTADOS: Se identificaron el conocimiento de las personas sobre la donacion, sus creencias, percepciones y actitudes, sus barreras y motivaciones, al igual que los medios mas eficaces para transmitir el mensaje a favor de la donacion voluntaria. CONCLUSIONES: Esta informacion servira como base para disenar una estrategia en los paises encaminada a promover la captacion y lealtad de los donantes voluntarios de sangre. Esta estrategia podra ser el sustento para llevar a la practica los cambios necesarios en la atencion y motivar a los donantes a regresar con regularidad a donar sangre.
Degree of Detail of Eyewitness Testimony and Mock Juror Judgments1

The influence of the degree of detail of eyewitness testimony on two sides of a court case was investigated in two experiments. In the first experiment subject-jurors read a civil court case involving an automobile-pedestrian accident. The plaintiff and the defendant presented conflicting eyewitness accounts. Judgments of the relative credibility of the eyewitnesses on each side and the percentage of negligence of the parties were influenced by the relative degree of detail of the eyewitness testimony on each side. In the second experiment subject-jurors read a criminal court case involving robbery and murder. The prosecution and defense presented conflicting eyewitness accounts. The degree of detail of the prosecution eyewitness testimony influenced judgments of guilt and judgments of the credibility of the eyewitnesses. An examination of the reasons for verdicts and credibility judgments revealed that some subjects inferred that an eyewitness who gave testimony with a greater degree of detail had a better memory for the trivial details and the culprit than an eyewitness who gave testimony with a lesser degree of detail. Implications of these results for the legal system are discussed.
Letter by Drinka regarding article, "Low-density lipoprotein cholesterol concentrations and death due to intraparenchymal hemorrhage: the Ibaraki Prefectural Health Study".

To the Editor: Noda et al1 reported that reduced low-density lipoprotein levels were associated with an elevated risk of death due to intraparenchymal hemorrhage. Lesions of the penetrating branches of cerebral …
Existence of the West β correction

We study the smearing effects, due to the nucleon's Fermi motion inside the deuteron, in a covariant way by using the Brodsky parametrization method and neglecting the spin of the particles involved. We find that West's ..beta.. correction is absent in the high-energy limit for hadronic scattering, but it is still there for leptonic scattering in the deep-inelastic limit. The form of the correction for the leptonic case is, however, different in our calculations from that given by West. We show explicitly that our approach is consistent and avoid some of the approximations made in the earlier contribution to this problem.
A systems framework for characterizing farm sustainability

Abstract This paper presents a framework for quantifying and diagnosing constraints to sustainability of farming systems. For a dynamic, stochastic, purposeful system, sustainability is defined as its ability to continue into the future. It can be expressed as the probability of continuation within specified threshold boundaries through a specified future period. Long-term, stochastic simulation of a system model serves as a basis for quantifying sustainability. Hypothesized constraints to sustainability can be tested and ranked by sensitivity analysis. Issues that arise when applying the framework to a particular farm include selecting an appropriate time frame, making assumptions about the future behaviour of system inputs, specifying criteria for system failure, and identifying potential determinants of sustainability. A previously published simulation study of Texas rice farms illustrates elements of the proposed approach.