ALBERT

Description: With the advances of Internet technologies and an explosive growth in the popularity of social media, an increasingly large part of human life is getting digitized and becoming available on the web. This phenomenon brings opportunities and motivates us to infer users’ situations by exploiting their interaction events in various social media such as online social networks, blogs and email. One of the key requirements of inferring situations from interaction events is to consider both the semantic and temporal aspects of events in the situation inference process. In this paper, we address this issue and propose a novel approach to exploiting users’ interaction events in social media to infer their situations. We present an ontology-based interaction event model that captures the properties of users’ interaction activities in social media. We further provide a rule-based situation specification technique that integrates the interaction event ontology (for semantically matching interaction events) with temporal event relationships (for correlating historical interaction events). We also provide a platform to realize the situation reasoning/inference process, which combines semantic matching and complex event processing. We conduct a performance evaluation of the platform to quantify its efficacy. The feasibility and applicability of our approach is demonstrated by developing a socially aware phone call application as a case study.

Description: Microbial consortia dominate glacial meltwater streams from polar regions, including the McMurdo Dry Valleys (MDV), where they thrive under physiologically stressful conditions. In this study, we examined microbial mat types and sediments found in 12 hydrologically diverse streams to describe the community diversity and composition within and across sites. Sequencing of the 16S rRNA gene from 129 samples revealed ~24 000 operational taxonomic units (〈97% DNA similarity), making streams the most biodiverse habitat in the MDV. Principal coordinate analyses revealed significant but weak clustering by mat type across all streams (ANOSIM R-statistic = 0.28) but stronger clustering within streams (ANOSIM R-statistic from 0.28 to 0.94). Significant relationships ( P 〈 0.05) were found between bacterial diversity and mat ash-free dry mass, suggesting that diversity is related to the hydrologic regimes of the various streams, which are predictive of mat biomass. However, correlations between stream chemistry and community members were weak, possibly reflecting the importance of internal processes and hydrologic conditions. Collectively, these results suggest that localized conditions dictate bacterial community composition of the same mat types and sediments from different streams, and while MDV streams are hotspots of biodiversity in an otherwise depauperate landscape, controls on community structure are complex and site specific.

Description: Petrological study of eruptive units in two locations along the Galápagos Spreading Center provides insight into how the rate of magma supply affects mid-ocean ridge magmatic systems. Study areas with lower magma supply (95°W) and higher magma supply (92°W) have similar spreading rates (53 and 55 mm a –1 ), but differ by 30% in the time-averaged rate of magma supply (0·3 x 10 6 and 0·4 x 10 6 m 3 km –1 a –1 ) as a result of varying proximity to the Galápagos hotspot. We use major and trace element compositions of glass and whole-rock samples, chemistry of mineral phases, and petrography to characterize parental magma variability, fractional crystallization and magma mixing in crustal reservoirs, and timescales of magmatic recharge relative to eruption. At the low magma supply study area, eruptible magma appears to be present only intermittently within the crust; magma recharge is probably infrequent, occurring with a periodicity of several hundred to one thousand years. The shallowest magma body in the crust is thought to be at ~3 km below the seafloor, and lavas are restricted to a relatively limited compositional range (6·2–9·1 wt % MgO). Magmatic evolution at this location is probably dominated by processes occurring within a crystal-rich mush, with limited subsequent residence in melt-dominated magma reservoirs. Eruptions here appear to be closely coupled to magmatic recharge events; lower MgO lavas have compositional trends controlled by mixing of low- and high-MgO magmas from compositionally distinct parents, and commonly contain both normally and reversely zoned crystals. In contrast, at the high magma supply study area, where a seismically imaged melt lens is located ~1·7 km below the seafloor, fractional crystallization within a melt-rich magma reservoir results in a larger range in major element compositions of the erupted magmas (2·7–8·2 wt % MgO) with less variation in trace element concentrations or ratios. Temperatures within the melt lens over the last several hundred years have varied by at least 100°C (1070–1170°C); cooling rates within the melt lens are estimated to be greater than 0·5°C per year. Relatively low-MgO lavas have over-enrichments in Cl that are best explained by assimilation of brine associated with hydrothermal circulation within the overlying crust. Between magmatic recharge events, resident magma fractionates and feeds one or more low-volume fissure eruptions. Small bodies of magma may become isolated from the larger magmatic system in the crust, allowing more extreme degrees of fractionation, locally reaching basaltic andesite. This study demonstrates that persistent melt lenses at intermediate rates of magma supply need not be ‘steady state’. The variations in magma composition among eruptive episodes at each location allow us to assess the temporal variability in magma reservoir properties at ridge segments along the Galápagos Spreading Center, in the context of regional variations in magma supply.

Description: Chemosynthetic sediment and planktonic community composition and sizes, aqueous geochemistry and sediment mineralogy were determined in 15 non-photosynthetic hot springs in Yellowstone National Park (YNP). These data were used to evaluate the hypothesis that differences in the availability of dissolved or mineral substrates in the bulk fluids or sediments within springs coincides with ecologically differentiated microbial communities and their populations. Planktonic and sediment-associated communities exhibited differing ecological characteristics including community sizes, evenness and richness. pH and temperature influenced microbial community composition among springs, but within-spring partitioning of taxa into sediment or planktonic communities was widespread, statistically supported ( P 〈 0.05) and could be best explained by the inferred metabolic strategies of the partitioned taxa. Microaerophilic genera of the Aquificales predominated in many of the planktonic communities. In contrast, taxa capable of mineral-based metabolism such as S o oxidation/reduction or Fe-oxide reduction predominated in sediment communities. These results indicate that ecological differentiation within thermal spring habitats is common across a range of spring geochemistry and is influenced by the availability of dissolved nutrients and minerals that can be used in metabolism.

Description: In this paper, we report a novel heterozygous mutation of A285V codon conversion on exon 4 of the desmin ( DES ), using whole exome sequencing (WES) in an isolated proband with documented dilated cardiomyopathy (DCM). This mutation is predicted to cause three-dimensional structure changes of DES. Immunohistological and electron microscopy studies demonstrated diffuse abnormal DES aggregations in DCM-induced-pluripotent stem cell (iPSC)-derived cardiomyocytes, and control-iPSC-derived cardiomyocytes transduced with A285V-DES. DCM-iPSC-derived cardiomyocytes also exhibited functional abnormalities in vitro . This is the first demonstration that patient-specific iPSC-derived cardiomyocytes can be used to provide histological and functional confirmation of a suspected genetic basis for DCM identified by WES.

Description: In modern communication environments, the ability to provide access control to information resources and software services in a context-aware manner is crucial. By leveraging the dynamically changing context information, we can achieve context-specific control over access to such resources and services, better satisfying the security and privacy requirements of the stakeholders. Existing access control approaches are highly domain-specific and they control access to services depending on the specific types of context information (e.g. location and time). One of the key limitations of the existing approaches is the lack of systematic capture and use of context information in making context-aware access control decisions. Therefore, new access control approaches are required for such dynamic and context-aware environments. Existing approaches define context as the state/situation of the entities. To achieve context-aware access control , in this paper we not only consider the states of the entities but also consider the states of the relationships between entities. We introduce a generic framework, OntCAAC ( Ont ology-based C ontext- A ware A ccess C ontrol ), that adopts semantic technologies in modelling dynamic contexts and corresponding access control policies. It includes a context model specific to access control, capturing the relevant context information. The context model also incorporates the ability to infer high-level implicit context information according to operator-defined rules. Using the context model, the policy model of the OntCAAC framework provides support for specifying and enforcing context-aware access control policies. We have developed a prototype implementation of the framework and have demonstrated its use in making context-aware access control decisions through two case studies from different domains. Experimental results show the feasibility of our approach and quantify the performance overhead of providing context-aware access control for software services.

Description: Mobile phones can record individual’s daily behavioral data as a time-series. In this paper, we present an effective time-series segmentation technique that extracts optimal time segments of individual’s similar behavioral characteristics utilizing their mobile phone data. One of the determinants of an individual’s behavior is the various activities undertaken at various times-of-the-day and days-of-the-week. In many cases, such behavior will follow temporal patterns. Currently, researchers use either equal or unequal interval-based segmentation of time for mining mobile phone users’ behavior. Most of them take into account static temporal coverage of 24-h-a-day and few of them take into account the number of incidences in time-series data. However, such segmentations do not necessarily map to the patterns of individual user activity and subsequent behavior because of not taking into account the diverse behaviors of individuals over time-of-the-week. Therefore, we propose a behavior-oriented time segmentation ( BOTS ) technique that takes into account not only the temporal coverage of the week but also the number of incidences of diverse behaviors dynamically for producing similar behavioral time segments over the week utilizing time-series data. Experiments on the real mobile phone datasets show that our proposed segmentation technique better captures the user’s dominant behavior at various times-of-the-day and days-of-the-week enabling the generation of high confidence temporal rules in order to mine individual mobile phone users’ behavior.