cssi/SciSciGPT-SciSciNet huggingface dataset:
Information activities within information horizons: A case for college students' personal information management

Abstract Personal information management behaviors appear differently by sources and by context. This study investigates personal information spaces from a quantitative approach and factors specific information behaviors and sources into information contexts. Using the information source horizon theory as a theoretical framework, college students' information behaviors to specific information sources were investigated in three personal information contexts (academic, health, and personal history contexts). In the college setting, students' personal information horizons echo the findings of previous studies that information contexts determine information horizons in general. In addition, specific information behaviors (collect, organize, and utilize) in this study are an important factor to influence personal information horizons. Certain information activities are observed in similar patterns regardless of contexts. The study suggests that the Information Horizon theory could be expanded to include information behaviors as an important determinant. From the data, radar charts visually present the relationships between information sources and activities, and they served as a collective form of information horizon maps.
Biomarkers of oral inflammation in perinatally HIV-infected and perinatally HIV-exposed, uninfected youth.

AIM To examine oral biomarkers that have been associated with periodontal disease progression in HIV-infected adults in perinatally HIV-infected and HIV-exposed but uninfected youth. MATERIAL AND METHODS This was a cross-sectional, multicentre substudy of youth participating in the Oral Health Pediatric HIV/AIDS Cohort study. Gingival crevicular fluid repository samples from participants with and without periodontal disease (using Gingival Index [GI] and Bleeding on Probing [BOP] parameters on dental examination) were tested for concentration levels of inflammatory biomarkers. Associations were assessed using Wilcoxon test and Spearman correlation. RESULTS For perinatal HIV youth (n = 129), the markers consistently elevated (p < .05) in sites with GI ≥2 and in sites with BOP were interleukin-1β, 6 and 13, macrophage inflammatory protein-1α and metalloproteinase-9. Serum tumour necrosis factor-α and soluble CD14 were positively correlated with a summary count of elevated cytokines. No associations were seen among HIV-uninfected subjects (n = 71). CONCLUSIONS The association of oral biomarkers of inflammation with clinical indicators of periodontal inflammation and systemic immune activation suggests that perinatal HIV-infected youth may be at higher risk for developing significant periodontal disease, associated with tooth loss and HIV progression. More frequent dental care of this group is needed to prevent potential periodontal progression.
Scheduling Shared Data Acquisition for Real-time Decision Making

This paper investigates scheduling policies for the acquisition of possibly overlapping sets of data items required to make multiple decisions by different deadlines. The work is motivated by military IoT applications in which a large number of sensors must collect intelligence data to make multiple decisions. For example, data from several cameras in a large city might be needed to decide where targets of interest are. We assume that network bandwidth is limited, creating a significant resource bottleneck (perhaps between sensors and the command center where decisions are made). This might be the case, for example, due to active interference by an adversary. We begin by introducing some of the observations and properties of the data acquisition scheduling problem followed by a heuristic algorithm based on the insights gained from these observations. Finally, we evaluate the new algorithm across multiple parameters and compare the results with previous heuristics, demonstrating improved performance of our solution.
Suicidal Behaviors and Help-Seeking Attitudes Among Deaf and Hard-of-Hearing College Students.

Objective The objective of this study was to examine the prevalence of suicidal ideation, suicide attempts, and help-seeking attitudes among D/HH and hearing college students. Method A total of 500,860 students completed the ACHA-NCHA-IIb (Fall 2011-Spring 2015). Survey administration and sampling methods differed across institutions. We randomly selected hearing students to have a 1:1 ratio of D/HH and hearing students (analytic N = 12,056). The mean age was 20.3 years, and the sample was predominantly white (68%) and female (65%). Multinomial and binary logistic regressions determined the relation between hearing status, suicide ideation and attempt, and help-seeking. Results D/HH college students were more likely than hearing college students to have seriously considered suicide or attempted suicide in their lifetime. [Correction added on November 26, 2019, after first online publication: The phrase "but not in the past year" was deleted in the previous sentence.] In adjusted analyses, D/HH college students were more likely than hearing college students to have attempted suicide in the past year (OR 2.42, 95% CI 1.85, 3.17). There were no differences between D/HH and hearing groups in help-seeking attitudes. Conclusions Findings from this national data set indicate that D/HH college students are more likely to consider or attempt suicide. These results underscore the need for focused suicide risk prevention interventions with this population.
Helen Keller's Legacy: A Blueprint for the Future:

Discusses history and evolution of the blindness system over the past 100 years, the impact of the Helen Keller Centennial Congress, the need for organizations to work together to accomplish mutual...
Uncooperative RF Direction Finding with I/Q Data

This paper studies the possibility of implicitly exploiting the characteristics of the In-phase and Quadrature components (I/Q components) of a transmitter using deep learning techniques for the problem of uncooperative direction finding using a single un-calibrated directional receiver. Radio "Direction Finding" (DF) is the problem of estimating the direction of a radio transmitter using features of the received signal. In this paper, we study this problem in the 2.4 GHz WiFi band and restrict ourselves to using I/Q information in a deep learning framework. For this work we used a custom designed data acquisition system built with commercial off-the-shelf (COTS) hardware and collected over the air raw I/Q signal data in both indoor and outdoor settings. The experimental results show that it is possible to reliably predict the bearing of the transmitter with an error bounded by 10 degrees in both indoor and outdoor environments. As our goal was to build an end-to-end system for direction finding with the raw I/Q data, we do not explicitly model the multi-path that inevitably arises in such situations and neither do we hand engineer features to mitigate the problems arising out of the same. Since the characteristics of a transmitter's I/Q data does not change in response to changes in the modulation schemes, the proposed approach has the ability to find the direction of specific emitters in-spite of changes to their modulation scheme.
Animal models built for women's brain health: Progress and potential.

Abstract Women and men have different levels of risk for a variety of brain disorders. Despite this well-known epidemiological finding, preclinical work utilizing animal models has historically only included male animals. The policies of funders to require consideration of sex as a biological variable has shifted the momentum to include female animals in preclinical neuroscience and to report findings by sex. However, there are many biological questions related to brain health that go beyond sex differences and are indeed specific to women. Here, the focus is on why animal models should be utilized in the pursuit of understanding women’s brain health, a brief overview of what they have provided thus far, and why they still hold tremendous promise. This review concludes with a set of suggestions for how to begin to pursue translational animal models in a way that facilitates rapid success and harnesses the most powerful aspects of animal models.
Cold plasma for SARS-CoV-2 Inactivation

SARS-CoV-2 infectious virions are viable on various surfaces (e.g., plastic, metals, cardboard) for several hours. This presents a transmission cycle for the human infection that can be broken by developing new inactivation approaches. We employed an efficient cold atmospheric plasma (CAP) with argon feed gas to inactivate SARS-CoV-2 on various surfaces including plastic, metal, cardboard, basketball composite leather, football leather, and baseball leather. These results demonstrate the great potential of CAP as a safe and effective means to prevent virus transmission and infections.
150 The survival outcome and prognostic factors of early stage ovarian cancer, FIGO stage IA and IC, after fertility-sparing surgery (FSS): a retrospective cohort study

Objectives Management of early stage ovarian cancer among women of reproductive age remains to be a challenge. This study aimed to determine the survival outcome and predictors of recurrence and survival among these women, with stage IA and IC ovarian cancer after unilateral salpingooophorectomy. Methodology A 13-year retrospective cohort study was conducted among 34 patients, 40 years and younger, with early stage ovarian cancer who underwent fertility-sparing surgery (FSS) from January 2005 to December 2018. Fertility outcome, recurrence-free survival (RFS) and overall survival (OS) were determined, including prognostic factors for recurrence and survival. Results Thirty-four of 661 (5.14%) new cases of ovarian cancer underwent FSS, with mean age of 23.71 ± 5.57 years. Successful pregnancy was seen in 9 cases. Recurrence was observed in 14.71% at a median time to recurrence of 31 months (range: 6–39), with three patients dying from the disease after recurrence. Overall RFS in early-stage ovarian cancer was 75% at 37–41 months. A lower probability of RFS was seen among incompletely staged patients, with epithelial type and grade 2 tumors. OS was 80% at 50–52 months after FSS. Complete surgical staging had higher probabilities of OS compared to incompletely staged cases. Epithelial and high grade tumors had lower probabilities of survival and poorer prognosis. Pregnancy has no statistically significant effect on survival and recurrence. Conclusion Fertility-sparing surgery can be effectively offered to young patients with early stage ovarian cancer. Pregnancy did not adversely affect recurrence and survival of early stage ovarian cancer after unilateral salpingooophorectomy.
Modelling price pressure in financial markets

Abstract We present experimental evidence that, unlike traditional assumptions in economic theory, security prices do not respond to pressure from their own excess demand. Instead, prices respond to excess demand of all securities, despite the absence of a direct link between markets. We propose a model of price pressure that explains these findings. In our model, agents set order prices that reflect the marginal valuation of desired future holdings, called “aspiration levels.” In the short run, as agents encounter difficulties executing their orders, they scale back their aspiration levels. Marginal valuations, order prices, and hence, transaction prices change correspondingly. The resulting price adjustment process coincides with the Global Newton Method. The assumptions of the model as well as its empirical implications are fully borne out by the data. Our model thus provides an economic foundation for why markets appear to search for equilibrium according to Newton’s procedure.
Optimal sequential contract with a risk-averse supplier

We study optimal contracts in environments where a risk‐averse supplier discovers cost information privately and gradually over time: the supplier is privately informed about its cost uncertainty at the time of contracting and discovers the realization of cost condition privately after contracting and before production. We show that both the buyer and the supplier prefer more cost uncertainty when the supplier is not very risk‐averse but less cost uncertainty when the supplier is sufficiently risk‐averse. However, the buyer always prefers to contract before the cost uncertainty resolves regardless of the supplier's degree of risk aversion. The nature of the optimal contract also depends on the supplier's risk preference. A separating contract is optimal when the supplier is not very risk‐averse; however, a pooling contract, which offers the same contract terms regardless of the cost uncertainty, can be optimal when the supplier becomes sufficiently risk‐averse. Moreover, the optimal production schedule is often characterized by “inflexible rules.” Contrat sequentiel optimal avec un fournisseur reticent au risque. Dans cet article, nous nous interessons aux contrats optimaux dans le cadre desquels un fournisseur reticent au risque decouvre les informations relatives aux couts de facon graduelle et confidentielle. Au moment de conclure le contrat, le fournisseur est informe des incertitudes liees aux couts, puis decouvre la concretisation des conditions tarifaires apres la signature du contrat et avant l’etape de production. Nous montrons que l’acheteur et le fournisseur preferent davantage d’incertitude liee aux couts lorsque le fournisseur n’est pas tres reticent au risque, mais moins d’incertitude lorsque le fournisseur est raisonnablement reticent au risque. Neanmoins, quel que soit le degre d’aversion au risque du fournisseur, l’acheteur prefere toujours conclure un contrat avant que les incertitudes liees aux couts ne se dissipent. La nature du contrat optimal depend egalement de la propension au risque du fournisseur. Un contrat separateur [separating contract] est optimal lorsque le fournisseur n’est pas tres enclin au risque. En revanche, un contrat rassemblant [pooling contract] offrant les memes conditions contractuelles peut s’averer optimal des lors que le fournisseur est raisonnablement reticent au risque, quelle que soit l’incertitude liee aux couts. De plus, le programme de production optimal est souvent caracterise par des regles inflexibles .
A Social Networks Model for Categorical Data

Social networks are currently extremely popular, and social networks models are useful in studying network phenomena. This paper describes models that are flexible in form, applicable to binary, categorical, or ordered data, reflecting a single relation among actors or multivariate or longitudinal relational ties, in one- or multi-mode networks.
Retroperitoneal malacoplakia

Malacoplakia is an uncommon, pathologically distinct, granulomatous disease that occurs most frequently in the urinary tract. It can present as an abdominal mass in a patient with urinary tract infection. A case of retroperitoneal malacoplakia with CT findings and successful treatment with radiation therapy is presented.
Parallel Algorithms for Masked Sparse Matrix-Matrix Products

Computing the product of two sparse matrices (SpGEMM) is a fundamental operation in various combinatorial and graph algorithms as well as various bioinformatics and data analytics applications for computing inner-product similarities. For an important class of algorithms, only a subset of the output entries are needed, and the resulting operation is known as Masked SpGEMM since a subset of the output entries is considered to be "masked out". Existing algorithms for Masked SpGEMM usually do not consider mask as part of multiplication and either first compute a regular SpGEMM followed by masking, or perform a sparse inner product only for output elements that are not masked out. In this work, we investigate various novel algorithms and data structures for this rather challenging and important computation, and provide guidelines on how to design a fast Masked-SpGEMM for shared-memory architectures. Our evaluations show that factors such as matrix and mask density, mask structure and cache behavior play a vital role in attaining high performance for Masked SpGEMM. We evaluate our algorithms on a large number of matrices using several real-world benchmarks and show that our algorithms in most cases significantly outperform the state of the art for Masked SpGEMM implementations.
Effect of constraints on Tiebout competition: Evidence from the Michigan school finance reform

In 1994, Michigan enacted a comprehensive school finance reform that not only significantly increased state aid to low-spending districts, but also placed significant limits on local discretion over school spending. These limits especially constrained the high-spending districts. This scenario affords us a unique opportunity to study the implications of such reforms on resource allocation, particularly as they differentially affected districts situated at different points of the pre-reform spending distribution. We find that the reform generally led to a negative effect on the growth of instructional expenditure and its share, as well as in teachers per pupil. But these declines were sharpest in the high-spending districts. Interestingly, while trends for shares of administration expenditure as well as administrators per pupil also showed across-the-board declines, these declines were actually the smallest for the high-spending districts. To the extent that instructional expenditures are more productive and contribute to student achievement more than administrative expenditures, these results suggest that loss of discretion acted as a disincentive for districts located throughout the spending distribution. Moreover, this disincentive effect was the strongest in the high-spending districts. These findings have important policy implications and suggest that school finance reforms (or other policies) that place significant restraints on local discretion can lead to unintended disincentive effects, which should be taken into account while devising policy.
Circumaortic renal collar.

A 50-year-old female prospective renal donor was referred for preoperative angiography. Intravenous urogram and Technetium Tc-99m Diethylenetriamine Pentaacetic Acid (DTPA) renal scan were unremarkable. Abdominal aortogram and bilateral selective renal angiogram showed normal arterial anatomy. The right kidney was drained by a single renal vein. However, the left kidney was drained by two renal veins that opened into the inferior vena cava (Figure 1). Circumaortic renal vein collar was suspected. Computerised tomographic (CT) scan and CT angiography of abdomen were performed to further delineate the spatial relationship of the left renal veins to the aorta. One of the left renal veins passed anterior to the aorta and posterior to the superior mesenteric artery (Figure 2), and another one i.e. the posterior division coursed inferiorly and medially behind the aorta (Figure 3) to reach the inferior vena cava forming the left renal vein collar around the aorta (Figure 4).
Real Estate Development

Real estate development is the process through which cities are built. It concerns all aspects relating to the creation of new real estate projects and adding value to existing projects – site selection, design, finance, entitlements, construction, leasing, and operations. This article addresses the steps of development, industry structure, property types, design and density, and the stages of development and real estate finance. It deals with the impact of business cycles, institutionalization of the industry, smart growth/urban sprawl, public–private development, technology, and sustainability on real estate development, both public and private. It concludes with the special social responsibilities that developers have for the built environment.
Adhesive tape: potential source of nosocomial bacteria.

Abstract During a 7-day period, a variety of bacteria, including opportunistic ones, were recovered from 23 rolls of adhesive tape being used in a 16-bed intensive care unit. All rolls of tape were sterile when received from the manufacturer. Mixed flora was recovered from a total of 15 rolls, whereas eight rolls yielded pure cultures. Organisms recovered included Staphylococcus aureus, Pseudomonas aeruginosa, and various species of Enterobacteriaceae. Although no illness or infection arising directly from contaminated adhesive tape has been documented, we feel that a potential source of infection has been identified. Most important is the fact that such tape may contaminate the hands of personnel who handle it. Also, the adhesive tape may directly contaminate a patient since it is widely used to secure artificial airways and various drainage tubes which results in the tape coming into close contact with the mucous membranes lining the patient's respiratory and urogenital tracts.
SIRPα/CD172a and FHOD1 Are Unique Markers of Littoral Cells, a Recently Evolved Major Cell Population of Red Pulp of Human Spleen

Asplenic individuals are compromised not only in their ability to destroy infectious agents, but are at increased risk for death from autoimmune disease, certain tumors, and ischemic heart disease. Enhanced mortality is attributed to lack of phagocytes sequestered in spleen that efficiently engulf and destroy appropriate targets, although related cells are found elsewhere. To determine whether a unique population regulates RBC-pathogen clearance and filtration of altered self, we reviewed the anatomic literature and analyzed in situ by immunohistochemistry and immunofluorescence the expression patterns of a little-characterized cell that dominates the splenic red pulp of humans and closely related primates: the venous sinus-lining or littoral cell (LC). High expression of the formin homology domain protein 1 outlines the LC population. Although LCs are endothelial-like in distribution, they express several macrophage-directed proteins, the RBC Duffy Ag receptor for chemokines and T cell coreceptor CD8α/α, yet they lack lineage-associated markers CD34 and CD45. Strikingly, SIRPα (CD172a) expression in human spleen concentrates on LCs, consistent with recent demonstration of a key role in RBC turnover and elimination versus release of infected or altered self. Our results indicate human LCs (SIRPα(+), formin homology domain protein 1(+), CD8α/α(+), CD34(-), CD45(-)) comprise a highly plastic barrier cell population that emerged late in primate evolution coordinate with CD8 expression. Unique to Hominidae, LCs may be the ultimate determinant of which cells recirculate after passage through human spleen.
The role of epitaxy and substrate on junction formation in ion-implanted HgCdTe

Abstract Ion implantation of B in Hg 1- x Cd x Te containing different structural defects (with and without top defect layer) grown both on CdTe and on CdTe/Al 2 O 3 substrates reveals a dependence of junction formation on the structural defects of layers and of substrates used for epitaxy. Techniques such a secondary ion mass spectroscopy, differential Hall, C - V , electron beam induced current, I - V , cathodoluminescence, and etch pit count lead to the findings presented in this paper. The presence of a top or surface defect layer in as-grown HgCdTe/CdTe effects the grading of the implant-induced n-type carrier concentration profile. As a consequence, the junction depth and thermal stability depend on the extent of damage and concentration of impurities in the layer. In the example presented here (top defect layer 4.0–5.0 μm thick), where only ≈ 5000 A were removed from the surface, the junction depth is ≈ 5.5 μm and is unstable above a range of temperatures around 100°C. Removal of the top defect layer makes the n + -side of the junction more abrupt, reduces the junction depth to 2.2-2.5 μm, and stabilizes the junction for limited anneals at temperatures around 200°C. The defect structure in the epilayer is affected by the defect structure of the base substrates, i.e., nonuniformity in dislocation distribution occured in layers grown on CdTe (with subgrain boundaries), but not in those grown on CdTe/Al 2 O 3 (containing a uniform high density of small dislocations). Since different substrates feature different defect structure, this difference affects the junction characteristics in the epitaxial layers. The evidence for this behavior has been established by previously reported data on devices made in HgCdTe/CdTe/Al 2 O 3 that have exhibited very good uniformity compared with those made in HgCdTe/CdTe.
Spontaneous contractions and bioelectric activity after differentiation in culture of presumptive neuromuscular tissues of the early frog embryo.

Gewebekulturen vonFroschneurula mit zugehorigen Muskelprimordien differenzieren in vitro und zeigen charakteristische Serien von Muskelkontraktionen. Elektrophysiologisch wurde nachgewiesen, dass die Muskelzuckungen durch endogene, komplexe, rhythmische Nervenaktivitat hervorgerufen werden konnen.
Compressive properties of Ti-6Al-4V auxetic mesh structures made by electron beam melting

Abstract In this current work, a Ti–6Al–4V 3-D re-entrant lattice auxetic structure is manufactured by the electron beam melting (EBM) process. Four different design configurations (two negative Poisson’s ratio values × two relative densities) were manufactured and tested under compressive stress. Two failure modes were observed whose occurrence appeared to be dependent on the ratio of vertical strut length to re-entrant strut length. A small deflection analytical model is presented that predicts yield strength and modulus for one type of design with good accuracy. Results also show that the re-entrant lattice structure possesses superior mechanical properties compared to regular foam structures. Limitations of the analytical model are also discussed.
Exemplary Irony: Cervantes's La señora Cornelia in Context

This essay examines how an ironic vision is created in the works of Cervantes and how the writer plays with the intertext. The structure of La senora Cornelia is analyzed in the context of the conventions of Golden Age narrative and as a basis for the developments and innovations to come later from the author of Don Quijote.
Comparing nominal and real quality scores on next-generation sequencing genotype calls

I seek to comprehensively evaluate the quality of the Genetic Analysis Workshop 17 (GAW17) data set by examining the accuracy of its genotype calls, which were based on the pilot3 data of the 1000 Genomes Project. Taking advantage of the 1000 Genomes Project/HapMap sample intersect, I compared GAW17 genotype calls to HapMap III, release 2, genotype calls for an individual. These genotype calls should be concordant almost everywhere. Instead I found an astonishingly low 65.4% concordance. Regarding HapMap as the gold standard, I assume that this is a GAW17 data problem and seek to explain this discordance accordingly. I found that a large proportion of this discordance occurred outside targeted regions and that concordance could be improved to at least 94.6% by simply staying within targeted regions, which were sequenced across more samples. Furthermore, I found that in certain individuals, high sample counts did little to improve concordance and concluded that quality scores for a certain sample’s sequence reads were simply incorrect.
Progress Report, Seismological Laboratory of the California Institute of Technology, 1957

On July 1, 1957 Beno Gutenberg retired as Director of the Seismological Laboratory and was succeeded by Frank Press. Beno Gutenberg remains a member of the staff. On February 5, 1958, Harry 0. Wood, who founded the Seismological Laboratory, passed away after a long illness. The long-standing condition of overcrowding it the Seismological Laboratory was corrected by the acquisition of an adjacent property. The new quarters, known as the Donnelley Laboratory, house offices for staff, visitors, and students as well as a library, map room, seismogram analysis room, and ultrasonic seismic model laboratory. An important feature of the Donnelley Laboratory is a tunnel 150 ft long, located in granite at a depth of 60 ft beneath the building. A linear strain seismograph and ultra long-period pendulums will be installed in the tunnel. The old quarters are being extensively remodeled and will be known as the Kresge Laboratory, housing the main seismograph vaults and recording rooms, experimental piers, electronics laboratory, machine shop, storage and stock rooms, photographic dark room, and offices for technicians.
Community-Based Perceptions of Neighborhood Health in Urban Neighborhoods

This community-based study explored perceptions of neighborhood health and neighborhood health characteristics to inform a new urban health neighborhood outreach program utilizing nurse and community health worker teams. Neighborhood residents and representatives from community agencies described their perceptions of personal health and neighborhood health through questionnaires and focus groups called community conversations. Respondents were more likely to report themselves as healthy and less likely to report their neighborhoods as healthy. Community conversations' common themes included respect, partnerships and relationships. Results provide guidance for planners of urban neighborhood health initiatives.
Long-Period Source Characteristics of the 1975 Kalapana, Hawaii, Earthquake

The 1975 Kalapana, Hawaii, earthquake occurred under the highly mobile south flank of Kilauea Volcano. It has been interpreted variously as a normal-faulting earthquake, a thrust-faulting earthquake, and a landslide. Primary evidence for the landslide model has been the failure of previous faulting models to explain the observed Love-wave radiation pattern and the tsunami amplitudes generated by the Kalapana event. Here, we present a reanalysis of the long-period, digital seismic data for this event. Centroid-moment-tensor analysis shows that the seismic radiation pattern can be explained well by thrust faulting on a plane dipping shallowly landward. The seismic moment of 3.8 × 10 20 N m ( M W 7.7) that we determine is approximately twice as large as earlier estimates. The geometry and seismic moment of the focal mechanism determined here are consistent with the observed tsunami amplitudes. Inversion of long-period body-wave waveforms shows that the earthquake source duration (∼72 sec) is unusually long for an earthquake of this size.
Immunocytochemical binding to neurons of serum from spinocerebellar degeneration patients.

Antineural antibodies have been described in sera of patients with neurodegenerative disorders. We looked for the presence of those antibodies in the sera of patients with spinocerebellar degeneration. Serum IgG from four patients with familial spinocerebellar degeneration showed strong binding to cerebral cortical neurons, Purkinje cells, and dorsal root ganglia of normal human tissue sections stained with the peroxidase antiperoxidase (PAP) method at serum dilution of 1:500. No binding to neuroglia cells or cells of the granular layer of the cerebellum was seen. Sera from four immediate, asymptomatic relatives (son or sibling) showed only moderate binding to Purkinje cells and to dorsal root ganglia, but not to cortical neurons. Sera from seven patients with neurological diseases other than spinocerebellar degeneration and from five healthy subjects showed no binding to neural elements. The findings may be of value in the diagnosis and screening of patients suspected of having spinocerebellar degenerati...
The influence of device geometry on instabilities in current-controlled negative resistors

Abstract Experiments have shown that either current-controlled negative differential resistance (CNDR) or threshold switching (TS) devices can be fabricated from a given chalcogenide glass. Device behaviour (CNDR versus TS) is controlled by the geometry of the thin film device, and is interpreted as arising from differences in the thermal boundary conditions between the various geometries. When lateral thermal instabilities are precluded, CNDR behaviour is obtained, and when such instabilities are allowed, TS behaviour is obtained. These results are predicted by consideration of the rate of entropy production in the device, thus confirming that it is device geometry and not choice of the material that governs whether CNDR or TS behaviour will be displayed.
Performance of digital GaAs E/D MESFET circuits fabricated in GaAs-on-Si substrate

A functional GaAs enhancement/ deplet on (E/D) 1K-bit SRAM and other digital circuits have been fabricated in a GaAs layer grown by MBE on a silicon substrate. These are the most complex digital circuits reported to date for GaAs-on-Si material. The device performance is compared with the bulk GaAs devices fabricated concurrently using identical processes. The average transconductances of enhancement and depletion FETs are found to be approximately 80% of those for bulk GaAs devices. A threshold voltage standard deviation as small as 27 mV across a two inch wafer has been realized. The GaAs-on-Si 1K-bit SRAM has row address access times ranging from 6 to 14 nsec which compares favorably to 4 to 12 nsec for the same SRAMs in bulk GaAs slices.
Bereavement: Course, Consequences, and Care

This paper discusses each of several potential consequences of bereavement. First, we describe ordinary grief, followed by a discussion of grief gone awry, or complicated grief (CG). Then, we cover other potential adverse outcomes of bereavement, each of which may contribute to, but are not identical with, CG: general medical comorbidity, mood disorders, post-traumatic stress disorder, anxiety, and substance use.
Semiempirical band structure of PtGa2.

A semiempirical band structure for ${\mathrm{PtGa}}_{2}$ was obtained by adjusting the ${\mathrm{AuGa}}_{2}$ parameters in the mixed-basis band-structure interpolation scheme to obtain agreement between the calculated total density of states (DOS) and x-ray photoemission spectroscopy data. Angle-resolved photoemission spectroscopy data collected from a ${\mathrm{PtGa}}_{2}$ (111) surface with a noble-gas-discharge lamp as excitation source were used to check the energies of the d bands. The ${\mathrm{PtGa}}_{2}$ band structure is compared to those of both elemental Pt and Au, and the gold color of ${\mathrm{PtGa}}_{2}$ is explained in terms of its Au-like DOS.
Outward migration of extrasolar planets to large orbital radii

Observations of structure in circumstellar debris discs provide circumstantial evidence for the presence of massive planets at large (several tens of astronomical units) orbital radii, where the time-scale for planet formation via core accretion is prohibitively long. Here, we investigate whether a population of distant planets can be produced via outward migration subsequent to formation in the inner disc. Two possibilities for significant outward migration are identified. First, cores that form early at radii a ∼ 10 au can be carried to larger radii via gravitational interaction with the gaseous disc. This process is efficient if there is strong mass loss from the disc - either within a cluster or due to photoevaporation from a star more massive than the Sun - but does not require the extremely destructive environment found, for example, in the core of the Orion nebula. We find that, depending upon the disc model, gas disc migration can yield massive planets (several Jupiter masses) at radii of around 20-50 au. Secondly, interactions within multiple planet systems can drive the outer planet into a large, normally highly eccentric orbit. A series of scattering experiments suggests that this process is most efficient for lower-mass planets within systems of unequal mass ratio. This mechanism is a good candidate for explaining the origin of relatively low-mass giant planets in eccentric orbits at large radii.
Power and Refrigeration Plants for Minimum Heat Exchanger Inventory

What has been accomplished to date on the question of how to minimize and allocate the heat exchanger inventory in power plants and refrigeration plants is summarized in a table. This table also highlights the three objectives of the present study. The first objective is to devise a much simpler model and analysis to reproduce in closed form Ibrahim et al.'s conclusions for fixed power and minimum UA (total heat exchanger inventory). The second objective is to consider the reverse of the refrigeration problem, and to minimize the total UA while holding the refrigeration load fixed. It will be shown analytically that (UA)[sub H] = (UA)[sub L] is once again a feature of the optimal design, the H and L referring to hot and cold ends of the heat exchanger. The third objective is to minimize the total heat exchanger inventory while holding the refrigerator power input fixed, and to show analytically that (UA)[sub H] = (UA)[sub L]. The overriding objective of this note is to demonstrate in the simplest analytical way possible that power plants and refrigeration plants share a common optimization principle. That principle is that the needed heat exchanger inventory is minimum when it is divided evenlymore » between the two ends of the cycle.« less
OPTIMIZATION OF ELASTIC FLEXIBLE BARS

Abstract A new optimization method for structures at targe displacements is proposed and applied to simple bar structures in this paper. In the method, the unknown height as a function of the axial coordinate of the beam depends on four parameters which are found numerically by an Adaptive Random Search method. The total volume of material in the beam is specified. A penalty objective function deals with the nonlinearity. Some numerical results are presented, discussed and compared with a numerical solution by Kamat and Mesquita.
An Optical Phenomenon

IN reference to the query of “V. P.” in NATURE of June 3 (p. 398), under the above title, I describe a simple experiment which will, in all probability, lead to an easy explanation.
Neoplasm Studies: III. Organization of Cells of Human Tumors in Tissue Culture

From time to time the growth of human tumors in vitro has been reported in the literature. In this paper is presented evidence of differentiation in the cellular outgrowths from explants of several human tumors. 1 Differentiation and functional activity have been reported in cultures of normal tissues. A striking example is the observation of Ebeling (1) on thyroid gland epithelium in which colloid-filled cysts were observed in cultures for as long as 129 days in vitro. Chambers and Kempton (2) have also reported the formation of secreting cysts in outgrowing renal epithelium of the chick mesonephros. The differentiations to be described here include the formation of acini in cultures of primary mammary carcinoma and of mixed tumors of the parotid gland, of “pearls” in cultures of metastatic squamous-cell epithelioma, and of endothelial tubes in cultures of angio-endothelioma. Cultures of all these specimens were maintained in a state of active proliferation for at least two months, and in many cases for four months. The most satisfactory culture medium was found to be a mixture of one part chicken blood-plasma, three parts human serum, and one part extract of either mouse or chick embryos in Tyrode solution. No attempt was made to use placental blood and bovine embryonic extract recently recommended by Gey (3). Many cultures were grown in media in which the serum used was from patients with carcinoma or sarcoma, the serum being either homologous or heterologous to the tumors to be grown. No significant differences were observed between growths in such media and in those with normal blood serum. The replacement of human serum with ascitic fluid or with sheep serum was unsatisfactory.
Force-Dependence of Lac-Repressor Mediated DNA Loop Formation

Protein-mediated DNA looping is a ubiquitous motif in transcriptional control schemes. Formation of these loops is driven by thermal fluctuations of the substrate DNA, which in turn are known to be exquisitely sensitive to mechanical constraints on the DNA. Because DNA in vivo is subject to a complex micromechanical environment, it is intriguing to study the effect of mechanical tension in the substrate DNA on the formation of these regulatory loops to investigate the role of mechanics in controlling gene regulation. For this purpose, we measured the formation and breakdown rates of lac repressor-mediated DNA loops under tension using constant-force axial optical tweezers.We observed that an incremental force of less than 100 femtonewtons is sufficient to reduce loop formation rate about sevenfold in a construct with an inter-operator spacing of 305 bp. This result suggests the possibility of mechanical pathways to control gene expression with forces that are two orders of magnitude lower than other typical intracellular forces acting on DNA, such as the forces exerted by RNA polymerase and molecular motors. Moreover, we developed a model that quantifies the relation between the force sensitivity of the loop formation rate and the angle between the incoming and outgoing DNA strand in the loop as a way to infer loop topology from our micromechanical measurements. We conclude that the LacI-mediated DNA loop prefers an anti-parallel loop topology over a parallel conformation.
Motorola's Silver Quill Program

A well planned author incentive program can turn word-shy engineers into a company's best spokespersons.
The Effects of Item Discrimination on the Standard Errors of Estimate Associated with Item-Examinee Sampling Procedures

A Monte Carlo study was conducted using item-examinee sampling procedures to examine the standard error of estimate for a given test's mean and variance. The main variables considered were test length, item difficulty, and item discrimination. The results indicate that optimal estimates, i.e., smallest standard error, of both mean and variance from a single item-examinee sampling plan may not be possible.
Geographies of Investment: How Do the Wealthy Build New Houses in Accra, Ghana?

World-city researchers have paid scant attention to cities in Africa. Van der Merwe (2004) emphasises that Sub-Saharan Africa is a huge information lacuna: African cities are often overlooked and portrayed as isolated and lower down in the global urban hierarchy. By some criteria African cities may appear isolated, but it cannot be concluded that African cities are irrelevant to the global economy. At the other extreme, King (2004) proposes that all cities be considered as world cities. This may be stretching the reality for most cities in Africa, considering that most states have not been fully liberalised. The reality for those cities leading in liberalisation efforts (e.g., Accra, Gaborone, Johannesburg) is likely to be somewhere in between. A more middle ground, argued by some scholars (e.g., Robinson, 2002; Rogerson, 2005), may be more on the mark. As Robinson (2002: 538) emphasises that when viewed from within these cities--"places allegedly off the global map"--the global economy is of enormous significance in shaping their fortunes and futures. There is large body of literature emerging on recent urban development and processes of land and housing marketisation and economic globalisation in developing countries (Wu, 2000; Rakodi, 1997). Urban development and processes has made the connections between the international and local dimensions of residential change more salient and reminiscent of the colonial period, when international factors heavily determined residential development. Researchers (e.g., Simone, 2004; Gugler, 2004) emphasise that African urbanites draw increasingly on material resources that can span the globe and probably more so today after twenty years of liberalisation policies. National data confirm this trend: the Government of Ghana found that aggregate income is only 64 percent of what households are spending (GSS 1996:57-60). Remittance flows account for much
AUTOMATION AND THE DIVISION OF LABOR

Specialization of function has been a cardinal principle of business organization since the beginning of the industrialization process. From Adam Smith's famous example of job specialization in the manufacture of pins to Frederick Taylor and Scientific Management, the idea that increasing job simplification meant increasing efficiency of operation has been among the principles applied to the organization of production. The division of labor resulting from industrial machine technology and large scale organization has been so continuous that it appeared to be an irreversible direction of change in contemporary societies.
Dual targeting improves microbubble contrast agent adhesion to VCAM-1 and P-selectin under flow

Abstract To improve ultrasound contrast agents targeted to the adhesion molecules P-selectin and VCAM-1 for the purpose of molecular imaging of atherosclerotic plaques, perfluorocarbon-filled phospholipid microbubble contrast agents were coupled by a polyethylene glycol–biotin–streptavidin bridge with mAb MVCAM.A(429), a sialyl Lewis x polymer (PAA-sLe x ), or both (dual). Approximately three hundred thousand antibody molecules were coupled to the surface of each microbubble. Recombinant mouse P-selectin and/or VCAM-1 coated on flow chambers showed saturation of binding at approximately 15 ng/μl, resulting in 800 and 1200 molecules/µm 2 for P-selectin and VCAM-1, respectively. Dual substrates coated with equal concentrations of P-selectin and VCAM-1 had site densities between 50 and 60% of single substrates. When microbubbles were perfused through flow chambers at 5 × 10 6 microbubbles/ml (wall shear stress from 1.5 to 6 dyn/cm 2 ) dual-targeted microbubbles adhered almost twice as efficiently as single-targeted microbubbles at 6 dyn/cm 2 . The present study suggests that dual-targeted contrast agents may be useful for atherosclerotic plaque detection at physiologically relevant shear stresses.
Adults in Involuntary Career Transition: An Analysis of the Relationship Between the Psychological and Career Domains

This investigation examined the relationship between psychological and career domains in a sample of 371 involuntarily laid off workers in the midwestern United States. The psychological domain was operationalized using the NEO Five Factor Inventory. The Career Transitions Inventory was used to examine internal psychological resources which adults may assess when making a career transition. A latent variable model was developed between the two sets of constructs to explore the possible direct relationships between these sets. The results indicated that neuroticism and openness to experience explained a significant amount of variance in the career transition variables. Self-efficacy was found to be predicted by four of the five personality factors. Implications concerning the importance of assessing underlying personality traits as well as more specific career constructs are discussed. In addition, the implications of these data for the greater integration of the psychological and career domains within our...
Microstimulation of a neural-network model for visually guided saccades

Microstimulation of many saccadic centers in the brain produces eye movements that are not consistent with either a strictly retinal or strictly head-centered coordinate coding of eye movements. Rather, stimulation produces some features of both types of coordinate coding. Recently we demonstrated a neural network model that was trained to localize the position of visual stimuli in head-centered coordinates at the output using inputs of eye and retinal position similar to those converging on area 7a of the posterior parietal cortex of monkeys (Zipser & Andersen 1988; Andersen & Zipser 1988). Here we show that microstimulation of this trained network, achieved by fully activating single units in the middle layer, produces “saccades” that are very much like the saccades produced by stimulating the brain. The activity of the middle-layer units can be considered to code the desired location of the eyes in head-centered coordinates; however, stimulation of these units does not produce the saccades predicted by a classical head-centered coordinate coding because the location in space appears to be coded in a distributed fashion among a population of units rather than explicitly at the level of single cells.