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Showing papers by "University of Wisconsin–Milwaukee published in 1999"


Book
01 Jan 1999
TL;DR: In this paper, the authors present a map-preface abbreviations for maps and a bibliography index for bibliographies of the maps. But they do not discuss the relation between the map and the bibliography.
Abstract: Maps Preface Abbreviations 1. Introduction 2. Genetic affiliation 3. Historical development 4. Dialects 5. Lexicon 6. Writing systems 7. Sound patterns 8. Word structure 9. Grammatical structure Select bibliography Index.

913 citations


Journal ArticleDOI
TL;DR: This polyphasic taxonomy takes into account all available phenotypic and genotypic data and integrates them into a consensus classification of Shewanella species based on information generated from this study and obtained from the literature.
Abstract: The genus Shewanella has been studied since 1931 with regard to a variety of topics of relevance to both applied and environmental microbiology. Recent years have seen the introduction of a large number of new Shewanella-like isolates, necessitating a coordinated review of the genus. In this work, the phylogenetic relationships among known shewanellae were examined using a battery of morphological, physiological, molecular and chemotaxonomic characterizations. This polyphasic taxonomy takes into account all available phenotypic and genotypic data and integrates them into a consensus classification. Based on information generated from this study and obtained from the literature, a scheme for the identification of Shewanella species has been compiled. Key phenotypic characteristics were sulfur reduction and halophilicity. Fatty acid and quinone profiling were used to impart an additional layer of information. Molecular characterizations employing small-subunit 16S rDNA sequences were at the limits of resolution for the differentiation of species in some cases. As a result, DNA-DNA hybridization and sequence analyses of a more rapidly evolving molecule (gyrB gene) were performed. Species-specific PCR probes were designed for the gyrB gene and used for the rapid screening of closely related strains. With this polyphasic approach, in addition to the ten described Shewanella species, two new species, Shewanella oneidensis and 'Shewanella pealeana', were recognized; Shewanella oneidensis sp. nov. is described here for the first time.

650 citations


Journal ArticleDOI
01 Dec 1999
TL;DR: The results of computer simulation under a more realistic model give convincing indication that the algorithm, if implemented on physical robots, will be robust against sensor and control error.
Abstract: We present a distributed algorithm for converging autonomous mobile robots with limited visibility toward a single point. Each robot is an omnidirectional mobile processor that repeatedly: 1) observes the relative positions of those robots that are visible; 2) computes its new position based on the observation using the given algorithm; 3) moves to that position. The robots' visibility is limited so that two robots can see each other if and only if they are within distance V of each other and there are no other robots between them. Our algorithm is memoryless in the sense that the next position of a robot is determined entirely from the positions of the robots that it can see at that moment. The correctness of the algorithm is proved formally under an abstract model of the robot system in which: 1) each robot is represented by a point that does not obstruct the view of other robots; 2) the robots' motion is instantaneous; 3) there are no sensor and control error; 4) the issue of collision is ignored. The results of computer simulation under a more realistic model give convincing indication that the algorithm, if implemented on physical robots, will be robust against sensor and control error.

585 citations


Journal ArticleDOI
TL;DR: In this paper, the authors derived expressions for the optimal filter function and signal-to-noise ratio for the cross-correlation of the outputs of two gravity-wave detectors, and the sensitivity levels required for detection are then calculated.
Abstract: We analyze the signal processing required for the optimal detection of a stochastic background of gravitational radiation using laser interferometric detectors. Starting with basic assumptions about the statistical properties of a stochastic gravity-wave background, we derive expressions for the optimal filter function and signal-to-noise ratio for the cross-correlation of the outputs of two gravity-wave detectors. Sensitivity levels required for detection are then calculated. Issues related to (i) calculating the signal-to-noise ratio for arbitrarily large stochastic backgrounds, (ii) performing the data analysis in the presence of nonstationary detector noise, (iii) combining data from multiple detector pairs to increase the sensitivity of a stochastic background search, (iv) correlating the outputs of 4 or more detectors, and (v) allowing for the possibility of correlated noise in the outputs of two detectors are discussed. We briefly describe a computer simulation that was used to ``experimentally'' verify the theoretical calculations derived in the paper, and which mimics the generation and detection of a simulated stochastic gravity-wave signal in the presence of simulated detector noise. Numerous graphs and tables of numerical data for the five major interferometers (LIGO-WA, LIGO-LA, VIRGO, GEO-600, and TAMA-300) are also given. This information consists of graphs of the noise power spectra, overlap reduction functions, and optimal filter functions; also included are tables of the signal-to-noise ratios and sensitivity levels for cross-correlation measurements between different detector pairs. The treatment given in this paper should be accessible to both theorists involved in data analysis and experimentalists involved in detector design and data acquisition.

562 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the relationship between anticipated costs and benefits of being a mentor, mentoring experience, and intentions to mentor among a sample of 275 executives, and found that those lacking experience tended to experience higher costs and fewer benefits than experienced individuals.
Abstract: We investigated the relationship between anticipated costs and benefits of being a mentor, mentoring experience, and intentions to mentor among a sample of 275 executives. Individuals lacking mentoring experience anticipated greater costs and fewer benefits than experienced individuals. Anticipated costs and benefits were related to intentions to mentor, and this relationship varied by mentoring experience. The results suggest that mentoring may be an intergenerational process. Copyright © 1999 John Wiley & Sons, Ltd.

448 citations


Journal ArticleDOI
TL;DR: It is concluded that tree swallows across North America are breeding earlier and that the most likely cause is a long‐term increase in spring temperature.
Abstract: Increasing evidence suggests that climate change has affected the breeding and distribution of wildlife. If such changes are due to global warming, then we should expect to see large-scale effects. To explore for such effects on avian reproduction, we examined 3450 nest records of tree swallows from across North America. The egg-laying date in tree swallows advanced by up to nine days during 1959-1991. This advance in phenology was associated with increasing surface air temperatures at the time of breeding. Our analysis controlled for several potentially confounding variables such as latitude, longitude, breeding density and elevation. We conclude that tree swallows across North America are breeding earlier and that the most likely cause is a long-term increase in spring temperature.

448 citations


Journal ArticleDOI
TL;DR: In this article, the relativistic precession model was proposed to interpret the kilohertz quasi-periodic oscillations (QPOs) as well as some of the lower frequency QPOs of low-mass X-ray binaries.
Abstract: A remarkable correlation between the centroid frequencies of quasi-periodic oscillations (or peaked noise components) from low-mass X-ray binaries has been recently discovered by Psaltis, Belloni, & van der Klis. This correlation extends over nearly three decades in frequency and encompasses both neutron star and black hole candidate systems. We discuss this result in light of the relativistic precession model, which has been proposed to interpret the kilohertz quasi-periodic oscillations (QPOs) as well as some of the lower frequency QPOs of neutron star low-mass X-ray binaries of the atoll and Z classes. Unlike other models, the relativistic precession model does not require the compact object to be a neutron star and can be applied to black hole candidates as well. We show that the predictions of the relativistic precession model match both the value and dependence of the correlation to very good accuracy and without resorting to additional assumptions.

380 citations


Journal ArticleDOI
TL;DR: This paper investigated factors that might influence Asian Americans' career choices and tested Lent et al.'s model to investigate the relationships among the predicting variables and the outcome variable (career choice) for 187 college students.

356 citations


Journal ArticleDOI
17 Sep 1999-Science
TL;DR: Experiments with dissimilatory Fe-reducing bacteria of the genus Shewanella algae grown on a ferrihydrite substrate indicate that the delta(56)Fe of ferrous Fe in solution is isotopically lighter than the ferriHydrite substrate, and the range in delta( 56)Fe values of sedimentary rocks may reflect biogenic fractionation.
Abstract: The (56)Fe/(54)Fe of Fe-bearing phases precipitated in sedimentary environments varies by 2.5 per mil (delta(56)Fe values of +0.9 to -1. 6 per mil). In contrast, the (56)Fe/(54)Fe of Fe-bearing phases in igneous rocks from Earth and the moon does not vary measurably (delta(56)Fe = 0.0 +/- 0.3 per mil). Experiments with dissimilatory Fe-reducing bacteria of the genus Shewanella algae grown on a ferrihydrite substrate indicate that the delta(56)Fe of ferrous Fe in solution is isotopically lighter than the ferrihydrite substrate by 1.3 per mil. Therefore, the range in delta(56)Fe values of sedimentary rocks may reflect biogenic fractionation, and the isotopic composition of Fe may be used to trace the distribution of microorganisms in modern and ancient Earth.

356 citations


Book ChapterDOI
01 Jan 1999
TL;DR: In this paper, the adjacency matrix, a matrix of O's and l's, is used to store a graph or digraph in a computer, and certain matrix operations are seen to correspond to digraph concepts.
Abstract: In order to store a graph or digraph in a computer, we need something other than the diagram or the formal definition. This something is the adjacency matrix, a matrix of O’s and l’s. The l’s correspond to the arcs of the digraph. Certain matrix operations will be seen to correspond to digraph concepts.

292 citations


Journal ArticleDOI
TL;DR: In this paper, the authors analyzed the different learning processes undertaken by novices and experts in clinical practice and found that novice learning is contingent on concept formation and assimilation, while expert learning is a constructivist process using active concept integration and self-initiated strategies.
Abstract: Although researchers have recently focused on the nature of expertise, the link between learning and the development of expertise remains to be more fully explored. The purpose of this study was to analyze the different learning processes undertaken by novices and experts. Twenty semi-structured interviews were conducted with novice and expert nurses for the purpose of analyzing and comparing how their learning developed in clinical practice. Results indicated that novice learning is contingent on concept formation and assimilation. Novice learning is also framed by the feelings novices experience in the context of practice. Expert learning, on the other hand, was identified as a constructivist process using active concept integration and self-initiated strategies. Additionally, novices and experts identified different organizational factors that facilitated or hindered their learning. Experts were able to articulate systemic issues that affected their learning, whereas novices identified disparate indivi...

Journal ArticleDOI
TL;DR: In this paper, the relationship between hydraulic conductivity and scale of measurement was analyzed for various types of sediments and rocks, and the scaling behavior can be described with the equation K = c (V)m, where c is a parameter characteristic of the geological medium that relates to geological variables such as average pore size and pore interconnectivity in porous media.
Abstract: Various types of sediments and rocks were analyzed for the relationship between hydraulic conductivity (K) and scale of measurement No variations of K with scale were observed for homogeneous media such as quartz-arenites (quartz sandstones). However, hydraulic conductivity increased with scale of measurement in heterogeneous media. The scaling behavior can be described with the equation K = c (V)m, where c is a parameter characteristic of the geological medium that relates to geological variables such as average pore size and pore interconnectivity in porous media, and probably fracture opening and fracture interconnectivity in fractured media. V is the volume of tested material (used as scale measure), and m is the exponent of the relationship (slope of the line on a log-log plot). The value of the exponent depends on the type or types of flow present. Porous flow media have an exponent of 0.5, multiple flow media an exponent between 0.5 and 1.0, and fracture and conduit flow controlled media an exponent of about 1.0. The more dominant fracture/conduit flow is relative to porous flow, the closer the exponent is to 1.0. K increases with scale up to a rock volume after which the aquifer approaches the properties of an equivalent homogeneous medium and K remains constant with scale. This volume (upper bound of the relationship) is related to the degree of heterogeneity in a medium. It is at a much larger scale in karstic media (if encountered at all) than in nonkarstic and more homogeneous media. Both confined and unconfined aquifers exhibit a similar scale dependence.

Journal ArticleDOI
TL;DR: Patients recovering from acute myocardial infarction may benefit from music therapy in a quiet, restful environment, and "treatment as usual" on anxiety levels and physiological indicators of cardiac autonomic function is compared.
Abstract: BACKGROUND Acute myocardial infarction places additional demands on an already compromised myocardium. Relaxing music can induce a relaxation response, thereby reversing the deleterious effects of the stress response. OBJECTIVES To compare the effects of relaxing music; quiet, uninterrupted rest; and "treatment as usual" on anxiety levels and physiological indicators of cardiac autonomic function. METHODS A 3-group repeated measures experimental design was used. Forty-five patients, 15 per group, with acute myocardial infarction were assigned randomly to 20 minutes of (1) music in a quiet, restful environment (experimental group); (2) quiet, restful environment without music (attention); or (3) treatment as usual (control). Anxiety levels and physiological indicators were measured. RESULTS Immediately after the intervention, reductions in heart rate, respiratory rate, and myocardial oxygen demand were significantly greater in the experimental group than in the control group. The reductions in heart rate and respiratory rate remained significantly greater 1 hour later. Changes in heart rate, respiratory rate, and myocardial oxygen demand in the attention group did not differ significantly from changes in the other 2 groups. The 3 groups did not differ with respect to systolic blood pressure. Increases in high-frequency heart rate variability were significantly greater in the experimental and attention groups than in the control group immediately after the intervention. State anxiety was reduced in the experimental group only; the reduction was significant immediately and 1 hour after the intervention. CONCLUSIONS Patients recovering from acute myocardial infarction may benefit from music therapy in a quiet, restful environment.

Journal ArticleDOI
TL;DR: A study that implemented concept maps as a methodology to teach and evaluate critical thinking showed a statistically significant difference between the first and final maps, indicative of the students' increase in conceptual and critical thinking.
Abstract: The purpose of this article is to describe a study that implemented concept maps as a methodology to teach and evaluate critical thinking. Students in six senior clinical groups were taught to use concept maps. Students created three concept maps over the course of the semester. Data analysis demonstrated a group mean score of 40.38 on the first concept map and 135.55 on the final concept map, for a difference of 98.16. The paired t value comparing the first concept map to the final concept map was -5.69. The data indicated a statistically significant difference between the first and final maps. This difference is indicative of the students' increase in conceptual and critical thinking.

Journal ArticleDOI
TL;DR: This paper reviewed the copious research on regional inequality in China and found that regional inequality is one of the major subjects of research on China, and is a major concern to the Chinese government.
Abstract: Regional inequality is one of the major subjects of research on China, and is a major concern to the Chinese government. This article reviews the copious research on regional inequality in China. I...

Journal ArticleDOI
TL;DR: Phenology has emerged recently as an important focus for ecological research, primarily because of its considerable promise to address important questions in global modeling, monitoring, and climate change as mentioned in this paper.
Abstract: Phenology has emerged recently as an important focus for ecological research, primarily because of its considerable promise to address important questions in global modeling, monitoring, and climate change. Remote sensing technological developments have also contributed to phenology’s resurgence, by generating extensive biosphere-related databases that require careful calibration and interpretation. This article reviews the major objectives, accomplishments, and challenges of contemporary phenological research, concentrating on papers presented in this thematic issue of the International Journal of Biometeorology and other recent venues relevant to global change. Strategies for the continued advancement toward global change-related goals are also presented. The crucial catalyst to this potential contribution will be the systematic development of observation networks on a national and global scale during the next decade and beyond.

Journal ArticleDOI
TL;DR: In this article, it was shown that the vacuum energy of a free quantized field of very low mass can significantly alter the recent expansion of the universe, which is consistent with the possibility of inflation in the early universe.
Abstract: We show that the vacuum energy of a free quantized field of very low mass can significantly alter the recent expansion of the universe. The effective action of the theory is obtained from a non-perturbative sum of scalar curvature terms in the propagator. We numerically investigate the semiclassical Einstein equations derived from it. As a result of non-perturbative quantum effects, the scalar curvature of the matter-dominated universe stops decreasing and approaches a constant value. The universe in our model evolves from an open matter-dominated epoch to a mildly inflating de Sitter expansion. The Hubble constant during the present de Sitter epoch, as well as the time at which the transition occurs from matter-dominated to de Sitter expansion, are determined by the mass of the field and by the present matter density. The model provides a theoretical explanation of the observed recent acceleration of the universe, and gives a good fit to data from high-redshift Type Ia supernovae, with a mass of about 10^{-33} eV, and a current ratio of matter density to critical density, Omega_0 <0.4 . The age of the universe then follows with no further free parameters in the theory, and turns out to be greater than 13 Gyr. The model is spatially open and consistent with the possibility of inflation in the very early universe. Furthermore, our model arises from the standard renormalizable theory of a free quantum field in curved spacetime, and does not require a cosmological constant or the associated fine-tuning.

Journal ArticleDOI
TL;DR: In this article, the rise and deformation of a gas bubble in an otherwise stationary liquid contained in a closed, right vertical cylinder is investigated using a modified volume-of-fluid (VOF) method incorporating surface tension stresses.
Abstract: The rise and deformation of a gas bubble in an otherwise stationary liquid contained in a closed, right vertical cylinder is investigated using a modified volume-of-fluid (VOF) method incorporating surface tension stresses. Starting from a perfectly spherical bubble which is initially at rest, the upward motion of the bubble in a gravitational field is studied by tracking the liquid–gas interface. The gas in the bubble can be treated as incompressible. The problem is simulated using primitive variables in a control-volume formulation in conjunction with a pressure–velocity coupling based on the SIMPLE algorithm. The modified VOF method used in this study is able to identify and physically treat features such as bubble deformation, cusp formation, breakup and joining. Results in a two-dimensional as well as a three-dimensional coordinate framework are presented. The bubble deformation and its motion are characterized by the Reynolds number, the Bond number, the density ratio, and the viscosity ratio. The effects of these parameters on the bubble rise are demonstrated. Physical mechanisms are discussed for the computational results obtained, especially the formation of a toroidal bubble. The results agree with experiments reported in the literature.

Journal ArticleDOI
04 Jun 1999-Science
TL;DR: Nearly all metabolic life-styles on the present Earth will be denied to organisms on Europa and which types of organisms, if any, are most likely to be found there are indicated.
Abstract: Recent reports that Jupiter's satellites Europa and Callisto may have ice-covered oceans have fueled speculation that they may be inhabited by living organisms. Gaidos et al. analyze the thermodynamic requirements for life on Europa by analogy with life on Earth today and during past "snowball" Earth episodes. They conclude that nearly all metabolic life-styles on the present Earth will be denied to organisms on Europa and indicate which types of organisms, if any, are most likely to be found there.

Book ChapterDOI
26 Mar 1999
TL;DR: A time- free, drift-free, multi-dimensional model of friction is introduced which exhibits four solution regimes: sticking, creeping, oscillating, and sliding and is applied to haptic rendering.
Abstract: A time-free, drift-free, multi-dimensional model of friction is introduced. A discrete implementation is developed which exhibits four solution regimes: sticking, creeping, oscillating, and sliding. Its computational solution is efficient to compute online and is robust to noise. It is applied to haptic rendering.

Journal ArticleDOI
TL;DR: Using 414 business undergraduates at two universities in the US, a 28-item computer self-efficacy scale is validated and used to examine the relationship between training and computer self,efficacy and user attitudes, suggesting that training significantly improved the computer Selfefficacy of males and females in this study.
Abstract: Using 414 business undergraduates at two universities in the US, a 28-item computer self-efficacy scale is validated and used to examine the relationship between (a) training and computer self-efficacy and (b) user attitudes and computer self-efficacy. Survey responses were collected both at the beginning and end of an introductory computer course. A principal factor analysis of the computer self-efficacy scale supported a conceptually meaningful four-factor solution with high alpha reliabilities. Results suggest that training significantly improved the computer self-efficacy of males and females in this study for all factors. Training programs seemed more effective for male and female respondents with positive attitudes toward computers. Training programs seemed less effective for respondents with negative attitudes toward computers. Implications of these findings are discussed and research opportunities described.

Journal ArticleDOI
TL;DR: In this article, the authors examine the relationship between students' inherent creativity, perceptions of the accounting profession, and decisions to major in accounting and examine the extent to which experience in an introductory accounting course changed students' perceptions and major choices.

Journal ArticleDOI
TL;DR: Results indicate that the transcription of new mRNA and subsequent protein synthesis in the amygdala may be essential for neural plasticity during this form of associative learning.
Abstract: In this study, the role of mRNA synthesis in the amygdala was studied during the acquisition of conditional fear. Rats with cannulas placed in the basolateral region of the amygdala were trained with a series of noise-shock pairings in a distinctive observation chamber. One half of the rats were pretreated with the mRNA synthesis inhibitor actinomycin-D (act-D). Responding to the training context and the auditory stimulus in a novel context measured by defensive freezing was assessed. Pretreatment with act-D significantly attenuated fear responses to both stimuli. Animals receiving act-D injections exhibited normal reactions to the conditioned stimulus-unconditioned stimulus pairings in the initial training session and displayed normal learning when retrained 7 days after injections. These results indicate that the transcription of new mRNA and subsequent protein synthesis in the amygdala may be essential for neural plasticity during this form of associative learning.

Journal ArticleDOI
TL;DR: In this article, the deuterium isotope effect was used to calculate the hydrogen pressure dependence for acetylene hydrogenation as a function of temperature, a value which varies between ∼1.05 and 1.3 as the temperature changes from 300 to 380 K.

Journal ArticleDOI
TL;DR: In this article, the role of variance and entropy in ordering distributions and random prospects is examined and the results are conveniently tabulated in terms of distribution parameters, which do not disturb the agreement between these rankings.

Journal ArticleDOI
TL;DR: In this paper, it was shown that rotation splits the degeneracy to zeroth order in the star's angular velocity Ω, and the resulting modes are generically hybrids, whose limit as Ω → 0 is a stationary current with axial and polar parts.
Abstract: Almost none of the r-modes ordinarily found in rotating stars exist, if the star and its perturbations obey the same one-parameter equation of state; and rotating relativistic stars with one-parameter equations of state have no pure r-modes at all, no modes whose limit, for a star with zero angular velocity, is a perturbation with axial parity. Similarly (as we show here), rotating stars of this kind have no pure g-modes, no modes whose spherical limit is a perturbation with polar parity and vanishing perturbed pressure and density. Where have these modes gone? In spherical stars of this kind, r-modes and g-modes form a degenerate zero-frequency subspace. We find that rotation splits the degeneracy to zeroth order in the star's angular velocity Ω, and the resulting modes are generically hybrids, whose limit as Ω → 0 is a stationary current with axial and polar parts. Lindblom & Ipser have recently found these hybrid modes in an analytic study of the Maclaurin spheroids. Since the hybrid modes have a rotational restoring force, they call them "rotation modes" or "generalized r-modes." Because each mode has definite parity, its axial and polar parts have alternating values of l. We show that each mode belongs to one of two classes, axial-led or polar-led, depending on whether the spherical harmonic with lowest value of l that contributes to its velocity field is axial or polar. We numerically compute these modes for slowly rotating polytropes and for Maclaurin spheroids, using a straightforward method that appears to be novel and robust. Timescales for the gravitational-wave driven instability and for viscous damping are computed using assumptions appropriate to neutron stars. The instability to nonaxisymmetric modes is, as expected, dominated by the l = m r-modes with simplest radial dependence, the only modes which retain their axial character in isentropic models; for relativistic isentropic stars, these l = m modes must also be replaced by hybrids of the kind considered here.

Journal ArticleDOI
TL;DR: In this article, through-bond electronic transport properties of 1,4-phenylene diisocyanide-metal junctions were analyzed with variable temperature conductance measurements to reveal the dominant electronic transport mechanisms.

Journal ArticleDOI
TL;DR: Shewanella putrefaciens (Strain MR-4), a gram negative facultative marine bacterium, was grown to stationary phase under both aerobic and anaerobic conditions using lactate as the sole carbon source, causing detection of isotopically depleted fatty acids in sediments to be falsely attributed to a terrestrial origin.

Journal ArticleDOI
TL;DR: Situation-specific theories could be based on the assumptions of post-empiricism, critical social theory and feminism, and or hermeneutics, and an integrative approach to developing this type of theories is suggested.
Abstract: It is imperative to further develop theoretical bases in nursing, which incorporate diversities and complexities in nursing phenomena, and which consider sociopolitical, cultural, and historic contexts of nursing encounters. Situation-specific theories are proposed in this work as a future direction of such theoretical bases in nursing. Philosophical roots and properties of situation-specific theories are discussed, and an integrative approach to developing this type of theories is suggested. Situation-specific theories could be based on the assumptions of post-empiricism, critical social theory and feminism, and or hermeneutics. Six properties of situation-specific theories are presented: (1) low level of abstraction, (2) reflection of specific nursing phenomena, (3) context, (4) connection to research and/or practice, (5) incorporation of diversities, and (6) limits in generalization. The proposed integrative approach to developing situation-specific theories includes (1) a nursing perspective, (2) a linkage among theory, research, and practice, and (3) a conceptual scheme based on internal and external dialogues.

Journal ArticleDOI
TL;DR: The most prevalent information needs experience related to race relations, crime and family, and their sources of unmet needs were lack of awareness of or access to existing information or resources as discussed by the authors.
Abstract: This article describes the information use environment (IUE) of African-American gatekeepers in Harambee, an inner-city neighborhood in Milwaukee, Wisconsin. In-depth one-on-one interviews were held with a purposive sample of 20 gatekeepers identified through community-based organizations between April and May 1997. Findings indicated that the gatekeepers were slightly better educated and earned more than the average Harambee resident. The most prevalent information needs experience related to race relations, crime and family, and their sources of unmet needs were lack of awareness of or access to existing information or resources. Interpersonal sources were preferred over all other sources because of concerns about trustworthiness and credibility of information. The implications of these findings for professional information services are discussed.