A Study of How Young Adults Leverage Multiple Profile Management Functionality in Managing their Online Reputation on Social Networking Sites

With privacy settings on social networking sites (SNS) perceived as complex and difficult to use and maintain, young adults can be left vulnerable to others accessing and using their personal information. Consequences of not regulating the boundaries their information on SNS include the ability for current and future employers to make career-impacting decisions based upon their online reputation that may include disqualifying them as job candidates. On SNS, such as Facebook, LinkedIn, and Twitter, young adults must decide on how to manage their online reputation by regulating boundaries to their own personal and professional information and identities. One known practice for the regulation of boundaries is the use of multiple profile management (MPM), where users of SNS create and use multiple accounts on a SNS and separate the social and professional identities that they disclose publicly and privately. The purpose of the study was to understand the lived experiences of young adults in how they regulate boundaries on SNS, through the use of MPM, as they manage their online reputation to different audiences. The practice was studied by applying interpretative phenomenological analysis (IPA) through interviewing young adults of 18-23 years of age, who use MPM on a SNS. Semi-structured interviews permitted participants to provide in-depth descriptions of their lived experiences. Eight themes were identified and described based on the analysis of the interviews that include: SNS use with online audiences, motivations for using MPM, the processes for the presentation of self, online search results, privacy settings, untagging SNS posts, self-editing and censorship, and new features. The themes describe the complexity and challenges that young adults face with regulating boundaries with their professional and social identities online through the use of MPM. Findings from this study have implications for a variety of audiences. Through the findings of this study, SNS developers can introduce new features, improve usability related to privacy management, and further encourage use of their networks. Users of SNS can use this study to understand risks of using SNS and for learning of practices for how to manage their online reputation on SNS

Security by Spatial Reference:Using Relative Positioning to Authenticate Devices for Spontaneous Interaction

Spontaneous interaction is a desirable characteristic associated with mobile and ubiquitous computing. The aim is to enable users to connect their personal devices with devices encountered in their environment in order to take advantage of interaction opportunities in accordance with their situation. However, it is difficult to secure spontaneous interaction as this requires authentication of the encountered device, in the absence of any prior knowledge of the device. In this paper we present a method for establishing and securing spontaneous interactions on the basis of emphspatial references that capture the spatial relationship of the involved devices. Spatial references are obtained by accurate sensing of relative device positions, presented to the user for initiation of interactions, and used in a peer authentication protocol that exploits a novel mechanism for message transfer over ultrasound to ensures spatial authenticity of the sender

Topological Charge Fluctuations and Low-Lying Dirac Eigenmodes

We discuss the utility of low-lying Dirac eigenmodes for studying the nature of topological charge fluctuations in QCD. The implications of previous results using the local chirality histogram method are discussed, and the new results using the overlap Dirac operator in Wilson gauge backgrounds at lattice spacings ranging from a~0.04 fm to a~0.12 fm are reported. While the degree of local chirality does not change appreciably closer to the continuum limit, we find that the size and density of local structures responsible for chiral peaking do change significantly. The resulting values are in disagreement with the assumptions of the Instanton Liquid Model. We conclude that the fluctuations of topological charge in the QCD vacuum are not locally quantized.Comment: 3 pages, 4 figures, Lattice2001(confinement

Wind farm potential is higher in prime habitat for uncommon soil crust lichens

Introduction: Biotic soil crust communities contribute valuable ecosystem services and biodiversity in steppe ecosystems. The uncommon crust lichens Acarospora schleicheri, Fuscopannaria cyanolepra, Rhizocarpon diploschistidina, and Texosporium sancti-jacobi are associated with fine-textured soils along rivers of the Columbia Basin. A. schleicheri and R. diploschistidina indicate late-successional habitat and may serve as indicators for other rare or cryptic species associated with similar habitats. Much of the most favorable habitat for these species has been lost to urban and agricultural development. We sought to overlay favorable habitats with wind farm development potential to assess whether these species are likely to be affected by renewable energy development. Methods: We overlaid habitat models for four lichen species on land use and wind farm potential maps. Using a sample of 5,000 points, we determined whether there were differences in probability of occurrence among wind farm potential classes within developed and natural lands using Multi-Response Permutation Procedures. Sites with modeled probability of occurrence greater than 60% were considered “favorable” habitats; for these, a χ 2 test allowed us to determine whether favorable habitats were associated with wind farm potential categories. Results: Sites that are developed for agriculture or have higher wind farm potential coincide with more favorable habitats for uncommon soil crust lichens. Of the favorable habitats for the four focal lichens, 28–42% are already affected by development or agriculture; 5–14% of favorable habitats remain in natural vegetation and are considered sites with fair or good potential for wind farms. Conclusions: Development of wind energy has the potential to negatively impact uncommon soil crust lichen species because favorable sites coincide with especially good habitat for these species. However, as these renewable energy resources are developed, we have the opportunity to ensure that valuable soil crust functions and diversity are maintained by surveying before construction and planning new facilities such that disturbance to existing habitat is minimized.Keywords: Acarospora schleicheri, Biotic soil crust, Agriculture, Texosporium sancti-jacobi, Land use, Columbia river, Rhizocarpon diploschistidina, Steppe, Fuscopannaria cyanolepr

Related Enteric Viruses Have Different Requirements for Host Microbiota in Mice

Accumulating evidence suggests that intestinal bacteria promote enteric virus infection in mice. For example, previous work demonstrated that antibiotic treatment of mice prior to oral infection with poliovirus reduced viral replication and pathogenesis. Here, we examined the effect of antibiotic treatment on infection with coxsackievirus B3 (CVB3), a picornavirus closely related to poliovirus. We treated mice with a mixture of five antibiotics to deplete host microbiota and examined CVB3 replication and pathogenesis following oral inoculation. We found that, as seen with poliovirus, CVB3 shedding and pathogenesis were reduced in antibiotic-treated mice. While treatment with just two antibiotics, vancomycin and ampicillin, was sufficient to reduce CVB3 replication and pathogenesis, this treatment had no effect on poliovirus. The quantity and composition of bacterial communities were altered by treatment with the five-antibiotic cocktail and by treatment with vancomycin and ampicillin. To determine whether more-subtle changes in bacterial populations impact viral replication, we examined viral infection in mice treated with milder antibiotic regimens. Mice treated with one-tenth the standard concentration of the normal antibiotic cocktail supported replication of poliovirus but not CVB3. Importantly, a single dose of one antibiotic, streptomycin, was sufficient to reduce CVB3 shedding and pathogenesis while having no effect on poliovirus shedding and pathogenesis. Overall, replication and pathogenesis of CVB3 are more sensitive to antibiotic treatment than poliovirus, indicating that closely related viruses may differ with respect to their reliance on microbiota. IMPORTANCE Recent data indicate that intestinal bacteria promote intestinal infection of several enteric viruses. Here, we show that coxsackievirus, an enteric virus in the picornavirus family, also relies on microbiota for intestinal replication and pathogenesis. Relatively minor depletion of the microbiota was sufficient to decrease coxsackievirus infection, while poliovirus infection was unaffected. Surprisingly, a single dose of one antibiotic was sufficient to reduce coxsackievirus infection. Therefore, these data indicate that closely related viruses may differ with respect to their reliance on microbiota

A single-amino-acid change in murine norovirus NS1/2 is sufficient for colonic tropism and persistence

Human norovirus (HuNoV) is the major cause of acute nonbacterial gastroenteritis worldwide but has no clear animal reservoir. HuNoV can persist after the resolution of symptoms, and this persistence may be essential for viral maintenance within the population. Many strains of the related murine norovirus (MNV) also persist, providing a tractable animal model for studying norovirus (NoV) persistence. We have used recombinant cDNA clones of representative persistent (CR6) and nonpersistent (CW3) strains to identify a domain within the nonstructural gene NS1/2 that is necessary and sufficient for persistence. Furthermore, we found that a single change of aspartic acid to glutamic acid in CW3 NS1/2 was sufficient for persistence. This same conservative change also caused increased growth of CW3 in the proximal colon, which we found to be a major tissue reservoir of MNV persistence, suggesting that NS1/2 determines viral tropism that is necessary for persistence. These findings represent the first identified function for NoV NS1/2 during infection and establish a novel model system for the study of enteric viral persistence

Origin of the dust bunny distribution in ecological community data

The distribution of sample units in multivariate species space typically departs strongly from the multivariate normal distribution. Instead of forming a hyperellipse in species space, the sample points tend to lie along high-dimensional edges of the space. This dust bunny distribution is seen in most ecological community data sets. The practical consequences of the distribution to the analysis of community data are well known and severe, but no one has demonstrated how population processes generate these problems. We evaluate potential causes of dust bunny distributions by simulating a large number of non-equilibrial communities under varying conditions, verifying that they resemble real data, then analyzing the relationship between the intensity of the dust bunny distribution in these data sets and the population and environmental parameters that gave rise to them. All community data sets, both simulated and real, departed strongly from multivariate normal and lognormal distributions. Four parameters influenced intensity of dust bunnies: time since community-replacing disturbance, number of environmental factors, dispersal limitation, and niche width. Samples measured soon after community-replacing disturbance had strong dust bunny distributions. Near-equilibrial communities sampled from a narrow range in environments lead to only weak dust bunnies. Community samples taken across multiple simultaneous strong environmental gradients are likely to show strong dust bunnies, regardless of the successional state, niche width of the component species, and degree of dispersal limitation. Dust bunny intensity depends not only on population processes and disturbance, but also on the properties of the sample, such as sample unit area or volume.Keywords: Simulation model, Environment, Community analysis, Disturbance, Niche widt

Lichen communities and species indicate climate thresholds in southeast and south-central Alaska, USA

Because of their unique physiology, lichen communities are highly sensitive to climatic conditions, making them ideal bioindicators for climate change. Southeast and south-central Alaska host diverse and abundant lichen communities and are faced with a more rapidly changing climate than many more southerly latitudes. We develop sensitive lichen-based indicators for tracking the effects of climate change in south-central and southeast Alaska. Using 196 plots, we model community composition and 12 individual species abundances in relation to synthetic climate variables. Both types of lichen indicator are closely related to the climate variable describing a transition from warm, wet oceanic climates to cooler, drier suboceanic climates. Lichen communities and individual species exhibited thresholds associated with average December minimum temperatures between –10.2 and –7.8°C and annual precipitation between 106 and 172 cm, suggesting rapid turnover with relatively small changes within these ranges. These climate conditions occur close to the coast in northern portions of the region and further inland in southeast Alaska. Because lichen communities in the threshold region may be most sensitive to a changing future climate, they should be targeted for monitoring efforts.Keywords: epiphytes, community analysis, Alaska, climate, threshold

Evidence Against Instanton Dominance of Topological Charge Fluctuations in QCD

The low-lying eigenmodes of the Dirac operator associated with typical gauge field configurations in QCD encode, among other low-energy properties, the physics behind the solution to the $U_A(1)$ problem (i.e. the origin of the $\eta'$ mass), the nature of spontaneous chiral symmetry breaking, and the physics of string-breaking, quark-antiquark pair production, and the OZI rule. Moreover, the space-time chiral structure of these eigenmodes reflects the space-time topological structure of the underlying gauge field. We present evidence from lattice QCD on the local chiral structure of low Dirac eigenmodes leading to the conclusion that topological charge fluctuations of the QCD vacuum are not instanton-dominated. The result supports Witten's arguments that topological charge is produced by confinement-related gauge fluctuations rather than instantons.Comment: 35 pages, 11 figure