Showing papers by "University of Massachusetts Boston published in 2014"

Data mining with big data

Abstract: Big Data concern large-volume, complex, growing data sets with multiple, autonomous sources. With the fast development of networking, data storage, and the data collection capacity, Big Data are now rapidly expanding in all science and engineering domains, including physical, biological and biomedical sciences. This paper presents a HACE theorem that characterizes the features of the Big Data revolution, and proposes a Big Data processing model, from the data mining perspective. This data-driven model involves demand-driven aggregation of information sources, mining and analysis, user interest modeling, and security and privacy considerations. We analyze the challenging issues in the data-driven model and also in the Big Data revolution.

High-Efficiency Broadband Meta-Hologram with Polarization-Controlled Dual Images

Abstract: Holograms, the optical devices to reconstruct predesigned images, show many applications in our daily life. However, applications of hologram are still limited by the constituent materials and therefore their working range is trapped at a particular electromagnetic region. In recent years, the metasurfaces, an array of subwavelength antenna with varying sizes, show the abilities to manipulate the phase of incident electromagnetic wave from visible to microwave frequencies. Here, we present a reflective-type and high-efficiency meta- hologram fabricated by metasurface for visible wavelength. Using gold cross nanoantennas as building blocks to construct our meta-hologram devices with thickness ∼ λ/4, the reconstructed images of meta-hologram show polarization- controlled dual images with high contrast, functioning for both coherent and incoherent light sources within a broad spectral range and under a wide range of incidence angles. The flexibility demonstrated here for our meta-hologram paves the road to a wide range of applications related to holographic images at arbitrary electromagnetic wave region.

A framework for protecting worker location privacy in spatial crowdsourcing

Abstract: Spatial Crowdsourcing (SC) is a transformative platform that engages individuals, groups and communities in the act of collecting, analyzing, and disseminating environmental, social and other spatio-temporal information. The objective of SC is to outsource a set of spatio-temporal tasks to a set of workers, i.e., individuals with mobile devices that perform the tasks by physically traveling to specified locations of interest. However, current solutions require the workers, who in many cases are simply volunteering for a cause, to disclose their locations to untrustworthy entities. In this paper, we introduce a framework for protecting location privacy of workers participating in SC tasks. We argue that existing location privacy techniques are not sufficient for SC, and we propose a mechanism based on differential privacy and geocasting that achieves effective SC services while offering privacy guarantees to workers. We investigate analytical models and task assignment strategies that balance multiple crucial aspects of SC functionality, such as task completion rate, worker travel distance and system overhead. Extensive experimental results on real-world datasets show that the proposed technique protects workers' location privacy without incurring significant performance metrics penalties.

Linking Biodiversity and Ecosystem Services: Current Uncertainties and the Necessary Next Steps

Abstract: Understanding when biodiversity conservation and ecosystem-service maintenance are compatible is needed within the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES). Here, we evaluate current understanding and uncertainties of the effects of biodiversity change on selected ecosystem services and suggest ways to further understand the links between biodiversity change and ecosystem services. We reviewed experiments, observations, and syntheses on the effects of species richness on six ecosystem services: forage, timber, fisheries, climate regulation, agricultural pest control, and water quality. Establishing a direct link from biodiversity to ecosystem-service provision has often been precluded by limited data (i.e., the amount, consistency, or generality of the data) and a mismatch between the variables measured and the final ecosystem service that is relevant to stakeholders. We suggest that encompassing syntheses and a network of interdisciplinary experiments under realistic conditions could fill these gaps and could inform the outcomes of alternative management and policy scenarios within IPBES.

Rapid evolution of a native species following invasion by a congener.

Abstract: In recent years, biologists have increasingly recognized that evolutionary change can occur rapidly when natural selection is strong; thus, real-time studies of evolution can be used to test classic evolutionary hypotheses directly. One such hypothesis is that negative interactions between closely related species can drive phenotypic divergence. Such divergence is thought to be ubiquitous, though well-documented cases are surprisingly rare. On small islands in Florida, we found that the lizard Anolis carolinensis moved to higher perches following invasion by Anolis sagrei and, in response, adaptively evolved larger toepads after only 20 generations. These results illustrate that interspecific interactions between closely related species can drive evolutionary change on observable time scales.

Rethinking chemistry: a learning progression on chemical thinking

Abstract: Dominant educational approaches in chemistry focus on the learning of somewhat isolated concepts and ideas about chemical substances and reactions. Reform efforts often seek to engage students in the generation of knowledge through the investigation of chemical phenomena, with emphasis on the development and application of models to build causal explanations and predict outcomes. However, chemistry has been characterized as a technoscience that blends scientific pursuit and technological goals. Besides searching for explanations, our discipline also involves the design of substances and processes to address relevant problems, as well as the evaluation of social, economic, and environmental benefits, costs, and risks associated with chemical knowledge and products. In order to develop authentic curricula, instruction, and assessments that are better aligned with the core goals and practices of chemistry, we need to understand how students' chemical thinking progresses over time. We define chemical thinking as the development and application of chemical knowledge and practices with the main intent of analyzing, synthesizing, and transforming matter for practical purposes. In this paper we present a blueprint of a theoretically sound and evidence-based foundation for an educational framework centered on the idea of chemical thinking. Our investigations are focused on the development of a learning progression that describes likely pathways in the evolution of students' chemical thinking with training in the discipline from grade 8 (age 13–14) through 16 (undergraduate completion).

Hippocampal gene expression changes underlying stress sensitization and recovery

Abstract: Chronic and acute stressors have been linked to changes in hippocampal function and anxiety-like behaviors. Both produce changes in gene expression, but the extent to which these changes endure beyond the end of stress remains poorly understood. As an essential first step to characterize abnormal patterns of gene expression after stress, this study demonstrates how chronic restraint stress (CRS) modulates gene expression in response to a novel stressor in the hippocampus of wild-type mice and the extent to which these changes last beyond the end of CRS. Male C57/bl6 mice were subjected to (1) a forced swim test (FST), (2) corticosterone (Cort) or vehicle injections, (3) CRS for 21 days and then a FST, or (4) allowed to recover 21 days after CRS and subjected to FST. Hippocampal mRNA was extracted and used to generate cDNA libraries for microarray hybridization. Naive acute stressors (FST and vehicle injection) altered similar sets of genes, but Cort treatment produced a profile that was distinct from both FST and vehicle. Exposure to a novel stress after CRS activated substantially more and different genes than naive exposure. Most genes increased by CRS were decreased after recovery but many remained altered and did not return to baseline. Pathway analysis identified significant clusters of differentially expressed genes across conditions, most notably the nuclear factor kappa-light-chain-enhancer of B cells (NF-κB) pathway. Quantitative reverse transcription-PCR (qRT-PCR) validated changes from the microarrays in known stress-induced genes and confirmed alterations in the NF-κB pathway genes, Nfkbia, RelA and Nfkb1. FST increased anxiety-like behavior in both the naive and recovery from CRS conditions, but not in mice 24h subsequent to their CRS exposure. These findings suggest that the effects of naive stress are distinct from Cort elevation, and that a history of stress exposure can permanently alter gene expression patterns in the hippocampus and the behavioral response to a novel stressor. These findings establish a baseline profile of normal recovery and adaptation to stress. Importantly, they will serve as a conceptual basis to facilitate the future study of the cellular and regional basis of gene expression changes that lead to impaired recovery from stress, such as those that occur in mood and anxiety disorders.

An Overview of Age-Friendly Cities and Communities Around the World

Abstract: Efforts to make cities and communities more age-friendly have gained significant momentum in recent years. Population aging and increased urbanization have challenged governments and other civic or...

Direct-bandgap GeSn grown on silicon with 2230 nm photoluminescence

Abstract: Material and optical characterizations have been conducted for epitaxially grown Ge1−xSnx thin films on Si with Sn composition up to 10%. A direct bandgap Ge0.9Sn0.1 alloy has been identified by temperature-dependent photoluminescence (PL) study based on the single peak spectrum and the narrow line-width. Room temperature PL emission as long as 2230 nm has also been observed from the same sample.

Being Transgender: The Experience of Transgender Identity Development

Abstract: This article is based on a grounded theory analysis of interviews with transgender-identified people from different regions of the United States. Participants held a variety of gender identities under the transgender rubric (e.g., crossdresser, transman, transwoman, butch lesbian). Interviews explored the participants' experiences in arriving at their gender identity. This article presents three clusters of findings related to the common processes of transgender identity development. This process was made possible by accessibility of transgender narratives that injected hope into what was a childhood replete with criticism and scrutiny. Ultimately, participants came to their identities through balancing a desire for authenticity with demands of necessity--meaning that they weighed their internal gender experience with considerations about their available resources, coping skills, and the consequences of gender transitions. The implications of these findings are considered in terms of their contribution to gender theory, research, and clinical support for transgender clients.

Social Desirability Bias in Self-reports of Physical Activity: Is an Exercise Identity the Culprit?

Abstract: Like that of other normative behaviors, much of the research on physical exercise is based on self-reports that are prone to overreporting. While research has focused on identifying the presence and degree of overreporting, this paper fills an important gap by investigating its causes. The explanation based in impression management will be challenged, using an explanation based in identity theory as an arguably better fitting alternative. Respondents were randomly assigned to one of two conditions: (1) a web instrument using direct survey questions, or (2) a chronological reporting procedure using text messaging. Comparisons to validation data from a reverse record check indicate significantly greater rates of overreporting in the web condition than in the text condition. Results suggest that measurement bias is associated with the importance of the respondents’ exercise identity, prompted by the directness of the conventional survey question. Findings call into question the benefit of self-administration for bias reduction in measurement of normative behaviors.

Pain Characteristics Associated with the Onset of Disability in Older Adults: The Maintenance of Balance, Independent Living, Intellect, and Zest in the Elderly Boston Study

Abstract: OBJECTIVES: To determine the effects of chronic pain on the development of disability and decline in physical performance over time in older adults. DESIGN: Longitudinal cohort study with 18 months of follow-up. SETTING: Urban and suburban communities. PARTICIPANTS: Community-dwelling older adults aged 65 and older (N = 634). MEASUREMENTS: Chronic pain assessment consisted of musculoskeletal pain locations and pain severity and pain interference according to the subscales of the Brief Pain Inventory. Disability was self-reported as any difficulty in mobility and basic and instrumental activities of daily living (ADLs, IADLs). Mobility performance was measured using the Short Physical Performance Battery (SPPB). Relationships between baseline pain and incident disability in 18 months were determined using risk ratios (RRs) from multivariable Poisson regression models. RESULTS: Almost 65% of participants reported chronic musculoskeletal pain at baseline. New onset of mobility difficulty at 18 months was strongly associated with baseline pain distribution: 7% (no sites), 18% (1 site), 24% (multisite), and 39% (widespread pain, P-value for trend < .001). Similar graded effects were found for other disability measures. Elderly adults with multisite or widespread pain had at a risk of onset of mobility difficulty at least three times as great as that of their peers without pain after adjusting for disability risk factors (multisite pain: risk ratio (RR) = 2.95, 95% confidence interval (CI) 1.58–5.50; widespread pain: RR = 3.57, 95% CI = 1.71–7.48). Widespread pain contributed to decline in mobility performance (1-point decline in SPPB, RR = 1.47, 95% CI = 1.08– 2.01). Similar associations were found for baseline pain interference predicting subsequent mobility decline and ADL and IADL disability. Weaker and less-consistent associations were observed with pain severity. CONCLUSION: Older community-dwelling adults living with chronic pain in multiple musculoskeletal locations have a substantially greater risk for developing disability over time and for clinically meaningful decline in mobility performance than those without pain. J Am Geriatr Soc 62:1007– 1016, 2014.

Improving Parenting Skills for Families of Young Children in Pediatric Settings: A Randomized Clinical Trial

Abstract: Importance Disruptive behavior disorders, such as attention-deficient/hyperactivity disorder and oppositional defiant disorder, are common and stable throughout childhood. These disorders cause long-term morbidity but benefit from early intervention. While symptoms are often evident before preschool, few children receive appropriate treatment during this period. Group parent training, such as the Incredible Years program, has been shown to be effective in improving parenting strategies and reducing children’s disruptive behaviors. Because they already monitor young children’s behavior and development, primary care pediatricians are in a good position to intervene early when indicated. Objective To investigate the feasibility and effectiveness of parent-training groups delivered to parents of toddlers in pediatric primary care settings. Design, Setting, and Participants This randomized clinical trial was conducted at 11 diverse pediatric practices in the Greater Boston area. A total of 273 parents of children between 2 and 4 years old who acknowledged disruptive behaviors on a 20-item checklist were included. Intervention A 10-week Incredible Years parent-training group co-led by a research clinician and a pediatric staff member. Main Outcomes and Measures Self-reports and structured videotaped observations of parent and child behaviors conducted prior to, immediately after, and 12 months after the intervention. Results A total of 150 parents were randomly assigned to the intervention or the waiting-list group. An additional 123 parents were assigned to receive intervention without a randomly selected comparison group. Compared with the waiting-list group, greater improvement was observed in both intervention groups ( P Conclusions and Relevance Self-reports and structured observations provided evidence of improvements in parenting practices and child disruptive behaviors that were attributable to participation in the Incredible Years groups. This study demonstrated the feasibility and effectiveness of parent-training groups conducted in pediatric office settings to reduce disruptive behavior in toddlers. Trial Registration clinicaltrials.gov Identifier:NCT00402857

Exact distributions for stochastic gene expression models with bursting and feedback.

Abstract: Stochasticity in gene expression can give rise to fluctuations in protein levels and lead to phenotypic variation across a population of genetically identical cells. Recent experiments indicate that bursting and feedback mechanisms play important roles in controlling noise in gene expression and phenotypic variation. A quantitative understanding of the impact of these factors requires analysis of the corresponding stochastic models. However, for stochastic models of gene expression with feedback and bursting, exact analytical results for protein distributions have not been obtained so far. Here, we analyze a model of gene expression with bursting and feedback regulation and obtain exact results for the corresponding protein steady-state distribution. The results obtained provide new insights into the role of bursting and feedback in noise regulation and optimization. Furthermore, for a specific choice of parameters, the system studied maps on to a two-state biochemical switch driven by a bursty input noise source. The analytical results derived provide quantitative insights into diverse cellular processes involving noise in gene expression and biochemical switching.

Adiabatic tracking of quantum many-body dynamics

Abstract: The nonadiabatic dynamics of a many-body system driven through a quantum critical point can be controlled using counterdiabatic driving, where the formation of excitations is suppressed by assisting the dynamics with auxiliary multiple-body nonlocal interactions. We propose an alternative scheme which circumvents practical challenges to realize shortcuts to adiabaticity in mesoscopic systems by tailoring the functional form of the auxiliary counterdiabatic interactions. A driving scheme resorting in short-range few-body interactions is shown to generate an effectively adiabatic dynamics.

Comparative analysis of spasers, vertical-cavity surface-emitting lasers and surface-plasmon-emitting diodes

Abstract: Theoretical analysis reveals that spasers do not differ fundamentally from conventional semiconductor lasers; differences are mainly technical and result from loss in the metal. Spasers are shown to have significantly inferior threshold currents and linewidths to those of vertical-cavity surface-emitting lasers, but their speed can be slightly greater.

Fabrication of Low-Cost Paper-Based Microfluidic Devices by Embossing or Cut-and-Stack Methods

Abstract: This article describes the use of embossing and “cut-and-stack” methods of assembly, to generate microfluidic devices from omniphobic paper and demonstrates that fluid flowing through these devices behaves similarly to fluid in an open-channel microfluidic device. The porosity of the paper to gases allows processes not possible in devices made using PDMS or other nonporous materials. Droplet generators and phase separators, for example, could be made by embossing “T”-shaped channels on paper. Vertical stacking of embossed or cut layers of omniphobic paper generated three-dimensional systems of microchannels. The gas permeability of the paper allowed fluid in the microchannel to contact and exchange with environmental or directed gases. An aqueous stream of water containing a pH indicator, as one demonstration, changed color upon exposure to air containing HCl or NH3 gases.

End-of-life care for blood cancers: a series of focus groups with hematologic oncologists.

Abstract: The authors' analysis suggests that hematologic oncologists need better clinical markers of when to initiate end-of-life care.

The natural history of left ventricular geometry in the community: clinical correlates and prognostic significance of change in LV geometric pattern.

Abstract: Objectives This study sought to evaluate pattern and clinical correlates of change in left ventricular (LV) geometry over a 4-year period in the community; it also assessed whether the pattern of change in LV geometry over 4 years predicts incident cardiovascular disease (CVD), including myocardial infarction, heart failure, and cardiovascular death, during an additional subsequent follow-up period. Background It is unclear how LV geometric patterns change over time and whether changes in LV geometry have prognostic significance. Methods This study evaluated 4,492 observations (2,604 unique Framingham Heart Study participants attending consecutive examinations) to categorize LV geometry at baseline and after 4 years. Four groups were defined on the basis of the sex-specific distributions of left ventricular mass (LVM) and relative wall thickness (RWT) (normal: LVM and RWT Results At baseline, 2,874 of 4,492 observations (64%) had normal LVM and RWT. Participants with normal geometry or concentric remodeling progressed infrequently (4% to 8%) to eccentric or concentric hypertrophy. Change from eccentric to concentric hypertrophy was uncommon (8%). Among participants with concentric hypertrophy, 19% developed eccentric hypertrophy within the 4-year period. Among participants with abnormal LV geometry at baseline, a significant proportion (29% to 53%) reverted to normal geometry within 4 years. Higher blood pressure, greater body mass index (BMI), advancing age, and male sex were key correlates of developing an abnormal geometry. Development of an abnormal LV geometric pattern over 4 years was associated with increased CVD risk (140 events) during a subsequent median follow-up of 12 years (adjusted-hazards ratio: 1.59; 95% confidence interval: 1.04 to 2.43). Conclusions The longitudinal observations in the community suggest that dynamic changes in LV geometric pattern over time are common. Higher blood pressure and greater BMI are modifiable factors associated with the development of abnormal LV geometry, and such progression portends an adverse prognosis.

Survival and Predictors of Mortality in Systemic Sclerosis‐Associated Pulmonary Arterial Hypertension: Outcomes From the Pulmonary Hypertension Assessment and Recognition of Outcomes in Scleroderma Registry

Abstract: Objective To assess cumulative survival rates and identify independent predictors of mortality in patients with incident systemic sclerosis (SSc)–associated pulmonary arterial hypertension (PAH) who had undergone routine screening for PAH at SSc centers in the US. Methods The Pulmonary Hypertension Assessment and Recognition of Outcomes in Scleroderma registry is a prospective registry of SSc patients at high risk for PAH or with definite pulmonary hypertension diagnosed by right-sided heart catheterization within 6 months of enrollment. Only patients with World Health Organization group I PAH (mean pulmonary artery pressure ≥25 mm Hg and pulmonary capillary wedge pressure ≤15 mm Hg without significant interstitial lung disease) were included in these analyses. Results In total, 131 SSc patients with incident PAH were followed for a mean ± SD of 2.0 ± 1.4 years. The 1-, 2-, and 3-year cumulative survival rates were 93%, 88%, and 75%, respectively. On multivariate analysis, age >60 years (hazard ratio [HR] 3.0, 95% confidence interval [95% CI] 1.1–8.4), male sex (HR 3.9, 95% CI 1.1–13.9), functional class (FC) IV status (HR 6.5, 95% CI 1.8–22.8), and diffusing capacity for carbon monoxide (DLco) <39% predicted (HR 4.2, 95% CI 1.3–13.8) were significant predictors of mortality. Conclusion This is the largest study describing survival in patients with incident SSc-associated PAH followed up at multiple SSc centers in the US who had undergone routine screening for PAH. The survival rates were better than those reported in other recently described SSc-associated PAH cohorts. Severely reduced DLco and FC IV status at the time of PAH diagnosis portended a poor prognosis in these patients.

Detailed multidisciplinary monitoring reveals pre- and co-eruptive signals at Nyamulagira volcano (North Kivu, Democratic Republic of Congo)

Abstract: This paper presents a thorough description of Nyamulagira’s January 2010 volcanic eruption (North Kivu, Democratic Republic of Congo), based on a combination of field observation and ground-based and space-borne data. It is the first eruption in the Virunga Volcanic Province that has been described by a combination of several modern monitoring techniques. The 2010 eruption lasted 26 days and emitted ∼45.5 × 106 m3 of lava. Field observations divided the event into four eruptive stages delimited by major changes in effusive activity. These stages are consistent with those described by Pouclet (1976) for historical eruptions of Nyamulagira. Co-eruptive signals from ground deformation, seismicity, SO2 emission and thermal flux correlate with the eruptive stages. Unambiguous pre-eruptive ground deformation was observed 3 weeks before the lava outburst, coinciding with a small but clear increase in the short period seismicity and SO2 emission. The 3 weeks of precursors contrasts with the only precursory signal previously recognized in the Virunga Volcanic Province, the short-term increase of tremor and long period seismicity, which, for example, were only detected less than 2 h prior to the 2010 eruption. The present paper is the most detailed picture of a typical flank eruption of this volcano. It provides valuable tools for re-examining former—mostly qualitative—descriptions of historical Nyamulagira eruptions that occurred during the colonial period.

The Causal Ordering of Prominence and Salience in Identity Theory: An Empirical Examination

Abstract: Identity theory invokes two distinct but related concepts, identity salience and prominence, to explain how the organization of identities that make up the self impacts the probability that a given identity is situationally enacted. However, much extant research has failed to clearly distinguish between salience and prominence, and their empirical relationship has not been adequately investigated, impeding a solid understanding of the significance and role of each in a general theory of the self. This study examines their causal ordering using three waves of panel data from 48 universities focusing on respondents' identities as science students. Analyses strongly support a causal ordering from prominence to salience. We provide theoretical and empirical grounds to justify this ordering while acknowledging potential variation in its strength across identities. Finally, we offer recommendations about the use of prominence and salience when measures of one or both are available or when analyses use cross-sectional data.

The New Heretics: Hybrid Organizations and the Challenges They Present to Corporate Sustainability

Abstract: Corporate sustainability has become mainstream; reaching into all areas of business management. Yet despite this progress, large-scale social and ecological issues continue to worsen. In this article, we examine how corporate sustainability has been enacted as a concept that supports the dominant beliefs of strategic management rather than challenging them to shift business beyond the unsustainable status quo. Against this backdrop, we consider how hybrid organizations (organizations at the interface between for-profit and nonprofit sectors that address social and ecological issues) are operating at odds with beliefs embedded in strategic management and corporate sustainability literatures. We offer six propositions that define hybrid organizations based on challenges they present to the beliefs embedded in these literatures and position them as new heretics of strategic management and corporate sustainability orthodoxy. We conclude with the implications of this heretical force for theory and suggest dire...