Showing papers by "San Jose State University published in 1995"

Organic Compounds Produced by Photolysis of Realistic Interstellar and Cometary Ice Analogs Containing Methanol

Abstract: The InfraRed (IR) spectra of UltraViolet (UV) and thermally processed, methanol-containing interstellar / cometary ice analogs at temperatures from 12 to 300 K are presented. Infrared spectroscopy, H-1 and C-13 Nuclear Magnetic Resonance (NMR) spectroscopy, and gas chromatography-mass spectrometry indicate that CO (carbon monoxide), CO2 (carbon dioxide), CH4 (methane), HCO (the formyl radical), H2CO (formaldehyde), CH3CH2OH (ethanol), HC([double bond]O)NH2 (formamide), CH3C([double bond]O)NH2 (acetamide), and R[single bond]C[triple bond]N (nitriles) are formed. In addition, the organic materials remaining after photolyzed ice analogs have been warmed to room temperature contain (in rough order of decreasing abundance), (1) hexamethylenetetramine (HMT, C6H12N4), (2) ethers, alcohols, and compounds related to PolyOxyMethylene (POM, ([single bond]CH2O[single bond](sub n)), and (3) ketones (R[single bond]C([double bond]O)[single bond]R') and amides (H2NC([double bond]O)[single bond]R). Most of the carbon in these residues is thought to come from the methanol in the original ice. Deuterium and C-13 isotopic labeling demonstrates that methanol is definitely the source of carbon in HMT. High concentrations of HMT in interstellar and cometary ices could have important astrophysical consequences. The ultraviolet photolysis of HMT frozen in H2O ice readily produces the 'XCN' band observed in the spectra of protostellar objects and laboratory ices, as well as other nitriles. Thus, HMT may be a precursor of XCN and a source of CN in comets and the interstellar medium. Also, HMT is known to hydrolyze under acidic conditions to yield ammonia, formaldehyde, and amino acids. Thus, HMT may be a significant source of prebiogenic compounds on asteroidal parent bodies. A potential mechanism for the radiative formation of HMT in cosmic ices is outlined.

Run by run process control: combining SPC and feedback control

Abstract: The run by run controller provides a framework for controlling a process which is subject to disturbances such as shifts and drifts as a normal part of its operation. The run by run controller combines the advantages of both statistical process control (SPC) and feedback control. It has three components: rapid mode, gradual mode, and generalized SPC. Rapid mode adapts to sudden shifts in the process such as those caused by maintenance operations. Gradual mode adapts to gradual drifts in the process such as those caused by build-up of deposition inside a reactor. The choice between the two modes is determined by the outcome from generalized SPC which allows SPC to be applied to a process while it is being tuned. The run by run controller has been applied to the control of a silicon epitaxy process in a barrel reactor. Rapid mode recovered the process within 3 runs after a disturbance. Gradual mode reduced the variation of the process by a factor of 2.7 as compared to historical data. >

Actinide Environmental Chemistry

Abstract: In order to predict release and transport rates, as well as design cleanup and containment methods, it is essential to understand the chemical reactions and forms of the actinides under aqueous environmental conditions. Four important processes that can occur with the actinide cations are: precipitation, complexation, sorption and colloid formation. Precipitation of a solid phase will limit the amount of actinide in solution near the solid phase and have a retarding effect on release and transport rates. Complexation increases the amount of actinide in solution and tends to increase release and migration rates. Actinides can sorb on to mineral or rock surfaces which tends to retard migration. Actinide ions can form or become associated with colloidal sized particles which can, depending on the nature of the colloid and the solution conditions, enhance or retard migration of the actinide. The degree to which these four processes progress is strongly dependent on the oxidation state of the actinide and tends to be similar for actinides in the same oxidation state.

Integrating top-down and bottom-up structural models of subjective well-being: A longitudinal investigation.

Abstract: Although there have been many recent advances in the literature on subjective well-being (SWB), the field historically has suffered from two shortcomings: little theoretical progress and lack of quasiexperimental or longitudinal design (E. Diener, 1984). Causal influences therefore have been difficult to determine. After collecting data over four time periods with 160 Ss we compared how well two alternative models of SWB (bottom-up and top-down models) fit the data. Variables of interest in both models were physical health, daily hassles, world assumptions, and constructive thinking. Results showed that both models provided good fit to the data, with neither model providing a closer fit than the other, which suggests that the field would benefit from devoting more time to examining how general dispositions toward happiness color perceptions of life's experiences. Results implicate bidirectional causal models of SWB and its personality and situational influences

Perceptions of intercultural communication competence and international student adaptation to an American campus

Abstract: International students are enrolling in American colleges and universities in increasing numbers, yet we know little of their communicative experiences on United States campuses. This study examined perceptions of intercultural communication competence and adaptation in international students studying on an American campus. Participants in the study were 101 international students enrolled in a medium‐sized university in the Midwest. Results suggest that while the affective and behavioral dimensions of intercultural communication competence are related to students' satisfaction with their communication skills, talking with American students was the single most important factor in perceptions of communication competency and adjusting to American life. Practical implications of these results for communication instruction are discussed.

Dating and Context of Three Middle Stone Age Sites with Bone Points in the Upper Semliki Valley, Zaire

Abstract: The extent to which the earliest anatomically modern humans in Africa exhibited behavioral and cognitive traits typical of Homo sapiens sapiens is controversial. In eastern Zaire, archaeological sites with bone points have yielded dates older than 89(-15)+22 thousand years ago by several techniques. These include electron spin resonance, thermoluminescence, optically stimulated luminescence, uranium series, and amino acid racemization. Faunal and stratigraphic data are consistent with this age.

Particle Formation in the Upper Tropical Troposphere: A Source of Nuclei for the Stratospheric Aerosol

Abstract: Atmospheric measurements and numerical calculations described here indicate that binary homogeneous nucleation of H2SO4-H2O particles occurs in the upper tropical troposphere. Particle concentrations decrease with increasing altitude above the tropical tropopause as a result of coagulation during the upward air transport produced by stratospheric circulations. During the extended periods of time that volcanic eruptions do not strongly influence stratospheric particle number concentrations, particles formed in the upper tropical troposphere provide nuclei upon which oxidized sulfur gases condense in the stratosphere. This particle source, coupled with aerosol microphysical properties and atmospheric transport, governs the number concentration of particles in the lower tropical and mid-latitude stratosphere.

Evaluation of Health Education Programs: Current Assessment and Future Directions

Abstract: Recently there has been an increase in the different types of strategies used in health education interventions, including an emphasis on broadening programs focused on individual behavior change to include larger units of practice. There has also been an increasing critique of the traditional physical science paradigm for evaluating the multiple dimensions inherent in many interventions. Additionally, there is a growing recognition of the importance of involving multiple stakeholders in designing, implementing, and evaluating interventions. Each of these factors carries specific evaluation challenges. With the overall aim of strengthening the evaluation of health education programs, this article aims to (a) present conceptual and technical design issues and options, (b) describe different approaches to evaluation, (c) highlight evaluation approaches that have been effective, (d) critique the limitations of traditional evaluation approaches, (e) examine promising approaches and implications for future evaluations, and (f) provide recommendations for evaluation designs, data collection methods, roles, responsibilities, and principles for evaluating interventions.

Random sampling from databases: a survey

Abstract: This paper reviews recent literature on techniques for obtaining random samples from databases. We begin with a discussion of why one would want to include sampling facilities in database management systems. We then review basic sampling techniques used in constructing DBMS sampling algorithms, e.g. acceptance/rejection and reservoir sampling. A discussion of sampling from various data structures follows: B + trees, hash files, spatial data structures (including R-trees and quadtrees). Algorithms for sampling from simple relational queries, e.g. single relational operators such as selection, intersection, union, set difference, projection, and join are then described. We then describe sampling for estimation of aggregates (e.g. the size of query results). Here we discuss both clustered sampling, and sequential sampling approaches. Decision-theoretic approaches to sampling for query optimization are reviewed.

Alertness management: strategic naps in operational settings.

Abstract: Managing fatigue in complex operational settings requires attention to multiple factors, including hours of service, scheduling, education and training, counter-measures, technology, and research. Alertness-management strategies can be used to promote safety, performance, and productivity in operational settings. These strategies can involve both preventive (used prior to duty/shift) and operational (used during duty/shift) approaches. Studies have demonstrated the effectiveness of naps to improve subsequent performance and alertness. Strategic naps can be used effectively to promote performance and alertness in operational settings. Two potential negative effects of naps, sleep inertia and effects on subsequent sleep periods, are discussed. Sleep inertia can involve sleepiness and decreased performance immediately upon awakening from a nap. It should be a consideration prior to implementing nap strategies in work environments. A study of planned rest periods in long-haul flight operations demonstrated the effectiveness of in-flight naps to promote performance and alertness during subsequent critical phases of flight (descent and landing). Empirical evaluation of alertness-management strategies during regular operations will be critical to their implementation. Combining strategies may be the most effective approach to managing fatigue engendered by 24-h operational demands. Other considerations prior to implementing alertness-management strategies in operational environments are discussed.

The development of subitizing in young children

Abstract: Across three experiments, 2- to 5-year-old children were found to enumerate accurately and reliably small arrays of objects irrespective of spatial arrangement and at a duration (200 ms) that precluded verbal counting. These findings indicate the presence in young children of a subitizing ability that is distinct from verbal counting. Subitizing appears to develop before verbal counting. The subitizing range increased with age during early childhood from 1-3 (the accurate enumeration range of infants) to 1-5 (the subitizing range of adults). Implications of these findings for theories of the development of numerical cognition are discussed.

Skeletal evidence of osteoarthritis: a palaeopathological perspective.

Abstract: Osteoarthritis (OA), or degenerative joint disease, is the most common form of joint pathology, and it has an extensive history. Indeed, it has been observed in a variety of fossil animals, and has been reported in the fossil remains of dinosaurs.' Among preindustrial human groups, as documented by skeletal remains, osteoarthritic changes are quite frequently the most common pathological lesion seen. Such degenerative changes have been described for archaeological samples varying widely in time and location.2\" In many cases,\"'5 frequencies of involvement have also been calculated and presented. Skeletal evidence from archaeological sites thus has potential to expand considerably the range of epidemiological data concerning OA. Human populations long since extinct can be sampled. Current epidemiological data are limited almost entirely to clinical samples drawn from urban contexts, mostly from North America and Europe. Earlier populations, ranging from arctic hunters, to early RomanoBritish agriculturists, to Mediaeval Nubians (and, obviously, many others) may have led lifestyles very different from those characteristic of contemporary groups. Accordingly, skeletal analysis provides a 'window' into a vastly broader sample of human groups than afforded solely by clinical samples. If varying levels of mechanical loading are important in the aetiology of OA, as suggested by the 'stress hypothesis','6 earlier populations could be expected to exhibit definitive patterns of joint involvement. Such patterns should be reflected in differential involvement both within and among joints; moreover, patterns of bilateral asymmetries, sex based variation, and perhaps, most crucially, clearly demarcated frequencies of involvement among prehistoric populations should be manifest.

Baldness and Coronary Heart Disease Rates in Men from the Framingham Study

Abstract: The authors assessed the relation between the extent and progression of baldness and coronary heart disease. Baldness was assessed twice, in 1956 and in 1962, in a cohort of 2,017 men from Framingham, Massachusetts. Extent of baldness was classified in terms of number of bald areas: no areas bald (n = 153), one area bald (n = 420), two areas bald (n = 587), and all areas bald (n = 857). Men who were assessed both times and who had two or fewer bald areas during the first evaluation were classified into one of three groups: "mild or no progression," "moderate progression," or "rapid progression." The cohort was followed for up to 30 years for new occurrences of coronary heart disease, coronary heart disease death, cardiovascular disease, and death due to any cause. The relations between the extent and progression of baldness and the aforementioned outcomes were assessed using a Cox proportional hazards model, adjusting for age and other known cardiovascular disease risk factors. Extent of baldness was not associated with any of the outcomes. However, the amount of progression of baldness was associated with coronary heart disease occurrence (relative risk (RR) = 2.4, 95% confidence interval (CI) 1.3-4.4), coronary heart disease mortality (RR = 3.8, 95% CI 1.9-7.7), and all-cause mortality (RR = 2.4, 95% CI 1.5-3.8). Rapid hair loss may be a marker for coronary heart disease.

Freezing behavior of stratospheric sulfate aerosols inferred from trajectory studies

Abstract: Based on the trajectory analysis presented in this paper, a new mechanism is described for the freezing of the stratospheric sulfate aerosols. Temperature histories based on 10-day back trajectories for six ER-2 flights during AASE-I (1989) and AAOE (1987) are presented. The mechanism requires, as an initial step, the cooling of a H2SO4/H2O aerosol to low temperatures. If a cooling cycle is then followed up by a warming to approximately 196-198 K, the aerosols may freeze due to the growth of the crystallizing embryos formed at the colder temperature. The HNO3 absorbed at colder temperatures may increase the nucleation rate of the crystalling embryos and therefore influence the crystallization of the supercooled aerosols upon warming. Of all the ER-2 flights described, only the polar stratospheric clouds (PSC), observed on the flights of January 24, and 25, 1989 are consistent with the thermodynamics of liquid ternary solutions of H2SO4/HNO3/H2O (type Ib PSCs). For those two days, back trajectories indicate that the air mass was exposed to sulfuric acid tetrahydrate (SAT) melting temperatures about 24 hours prior to being sampled by the ER-2. Temperature histories, recent laboratory measurements, and the properties of glassy solids suggest that stratospheric H2SO4 aerosols may undergo a phase transition to SAT upon warming at approximately 198 K after going through a cooling cycle to about 194 K or lower.

Questioning ubiquitous computing

Abstract: Ubiquitous Computing represents the most explicit attempt yet to move computing technology beyond the confines of tool usage towards a pervasive penetration of everyday bye. We outline a critical analysis of this technology based on a close examination of the proposals advancing it. After introducing a framework for understanding modern technology, we develop an interpretation of Ubiquitous Computing concentrating on its guiding principles, technological infrastructure, and scenarios. Next, we examine possible ways in which this technology could transform the human-world relationships that it would mediate. Finally, we analyze the particular kind of technical thinking underlying Ubiquitous Computing by focusing on the explicit and implicit assumptions and just$cations supporting the proposals. By means of this analysis, we arrive at a preliminary characterization of both the potential effects of Ubiquitous Computing on human-world relationships and the kind of technical thinking from which it originates.

Perception-Based Self-Localization Using Fuzzy Locations

Abstract: We describe a fuzzy-based approach to self localization to support indoor robot navigation. Our approach is perception-based: clues extracted by the perceptual apparatus are matched against an approximate map to obtain an estimate of the robot's location in the map. Each perceptual clue is treated as a source of partial locational information, represented by a fuzzy set; other sources, like odometry or external measurements, are also treated in this way. Information coming from different sources is combined using a fuzzy aggregation operator. We illustrate our approach by showing experiments performed on a mobile robot, Flakey.

Long term periodicity in solar wind velocity during the last three solar cycles

Abstract: Solar wind measurements from the Pioneer 10, Pioneer 11, Voyager 2, IMP 8, and Pioneer Venus Orbiter (PVO) spacecraft were examined to search for long-term periodicities during the last three solar cycles. For the time of the last solar maximum, these measurements confirm the existence of the periodic 1.3-year enhancements in solar wind velocity reported by Richardson et al. (1994). For most of the preceding two solar cycles, long-term velocity enhancements occurred that were similar in structure but lacked the 1.3-year periodicity. It appears that long-term enhancements in solar wind velocity, with durations on the order of a few months to a year, are a common feature throughout the heliosphere.

Off-road cycling injuries. An overview

Abstract: Off-road bicycles, commonly called ‘mountain bikes’, have become increasingly popular worldwide since their introduction in the western US in the late 1970s. This popularity is partly because these vehicles can be ridden on a wide variety of terrain which is not accessible to other types of bicycle. Although early versions were rather crude, off-road bicycles today typically include high strength, lightweight frames with a wide array of available suspension and braking systems. Virtually all aspects of the technology continue to evolve, including components and protective equipment. As the popularity of off-road cycling has increased, so too has the interest and level of participation in the competitive aspects of the sport. Currently, 2 organisations — the National Off-Road Bicycle Association (NORBA) and the Union Cycliste Internationale (UCI) — sponsor the major events within the US and around the world. To date, the majority of studies have been descriptive in nature, with data collected via self-report, questionnaire formats. Only 1 prospective study has been reported thus far, which surveyed a major international competition held in the US in 1994. Injury rates calculated on the basis of injuries per ride or event in competitive venues have been reported, ranging from 0.2 to 0.39% compared with 0.30% for recreational participants. Retrospective data collected from recreational and competitive riders indicate that from 20 to 88% of those surveyed reported having sustained an injury during the previous year of participation. The majority of injuries appear to be acute, traumatic episodes involving the extremities, with contusions and abrasions being the most common. In general, the incidence of more severe injuries such as dislocations, fractures and concussions is low. Comparisons between road and off-road cycling events indicate that off-road cyclists sustain more fractures, dislocations and concussions than their road-event counterparts. Future research should incorporate epidemiological methods of data collection to determine the relationships between vehicle design, terrain and safety equipment and riding-related accidents. Further, those engaged in such research should attempt to set a standard definition for injury.

Analyzing the uses and gratifications concept of audience activity with a qualitative approach: Media encounters during the 1989 Loma Prieta earthquake disaster

Abstract: Diaries and narratives produced by 29 college students during the 1989 Loma Prieta earthquake served as the data for a qualitative analysis grounded in the conventional philosophy, if not the traditional methodology, of the uses and gratifications perspective. Two hundred ninety‐nine individual media episodes were interpreted. Audience activity before, during, and after media exposure was studied through the application of the Levy and Windahl Typology of Audience Activity which demonstrated the operation of the nine types of media activity proposed by its creators. Conclusions call for the redirection (rather than abandonment) of audience‐based research away from general‐trend audience consumption and towards more specific cultural interaction of people with media.

Predicting muscular strength in women: a preliminary study.

Abstract: (1995). Predicting Muscular Strength in Women: A Preliminary Study. Research Quarterly for Exercise and Sport: Vol. 66, No. 2, pp. 168-172.

Cockpit-Cabin Communication: I. A Tale of Two Cultures

Abstract: Several dramatic accidents have emphasized certain deficiencies in cockpit-cabin coordination and communication There are historical, organizational, environmental, psychosocial, and regulatory factors that have led to misunderstandings, problematic attitudes, and suboptimal interactions between the cockpit and cabin crews Our research indicates the basic problem is that these two crews represent two distinct and separate cultures and that this separation serves to inhibit satisfactory teamwork A survey was conducted at two airlines to measure altitudes of cockpit and cabin crews concerning the effectiveness of their communications This article includes recommendations for the improvement of communications across the two cultures

Combining Research, Advocacy, and Education: The Methods of the Grandparent Caregiver Study

Abstract: This article presents a case study of the effective synergy of health education inquiry, community collaboration, and policy advocacy. Using the Grandparent Caregiver Study as the example, the authors focus on key methodological decisions that enabled them to incorporate research, education, and advocacy activities into an ever-growing project on a modest budget. The study itself centered on two in-depth interviews with each of 71 African American grandmothers raising young grandchildren due to the crack cocaine epidemic in Oakland, California. The case study demonstrates ways in which health education research can increase the efficacy of individuals and disenfranchised groups to define problems, voice their concerns, and advocate for more just and healthy public policies. Through discussion of the authors' methods and activities, they suggest strategies through which research participants, service providers, and policymakers can work together to bring a new issue to the policy arena through a collaborative and empowering research process.

Workplace training, workplace learning : a case study

Abstract: Workplace training may be viewed as an instrumental activity that can be evaluated as to its efficiency in conveying requisite skills and knowledge. This paper develops a broader analysis of training by analyzing a series of classes offered to the production workers of a computer manufacturer. The training curriculum failed in its instrumental function, and instead was used by trainees, support staff trainers, and production floor management to pursue diverse agendas. It also simplified organizational "messes" by making them seemingly amenable to rational problem solving. On-the-job training, the formal training classes, and daily life on the production floor are analyzed as distinct "arenas for learning" that reflected organizational power as much as efficient pedagogy. The implications of this analysis for a world in which enhancing the skills of workers is widely deemed essential are also explored.

History and Overview

Abstract: Clinical psychology has grown tremendously since 1896, the year Lightner Witmer founded the world’s first psychological clinic at the University of Pennsylvania (Reisman, 1976). While once associated merely with clinic-based evaluation and treatment of childhood learning problems, the field of clinical psychology has expanded into a wide range of client populations, clinical activities, and work settings.

Effect of rework strategies on cycle time

Abstract: In batch manufacturing, a fraction of the batch, or “lot,” may require reworking because its members fail to conform to standards. A rework station “undoes” the previous operation, so that the nonconforming members can go through the same operation additional times. This paper explores how policies dealing with these nonconforming members affect the cycle time of a facility. Two different operating policies can be followed. In one, the “mother” lot is held back while the “child” sub-lots are reworked, after which all members are reunited for the next operation. In the other, the mother lot is allowed to proceed to the next operation while the child is held back; reworked members are then introduced by one of three methods: In the first, the reworked members of each mother lot are introduced by themselves. In the second, a minimum order quantity of reworked members is designated and a new lot introduced when this level is reached. In the third, the reworked members are added to the next mother lot that visits the operation. In this paper, queuing models are developed for these policies, and the policies are simulated with regard to cycle time. Simulation of a wafer fabrication model is used to determine the effectiveness of these policies and their impact on cycle time.

A Comparative Study of a Penalty Function, a Repair Heuristic and Stochastic Operators with the Set-Covering Problem

Abstract: In this paper we compare the effects of using various stochastic operators with the non-unicost set-covering problem. Four different crossover operators are compared to a repair heuristic which consists in transforming infeasible strings into feasible ones. These stochastic operators are incorporated in GENEsYs, the genetic algorithm we apply to problem instances of the set-covering problem we draw from well known test problems. GENEsYs uses a simple fitness function that has a graded penalty term to penalize infeasibly bred strings. The results are compared to a non GA-based algorithm based on the greedy technique. Our computational results are then compared, shedding some light on the effects of using different operators, a penalty function, and a repair heuristic on a highly constrained combinatorial optimization problem.