College Students and Yik Yak: An Exploratory Mixed-Methods Study

This study, employing an exploratory mixed-methods approach, explores college students’ use of Yik Yak, a pseudo-anonymous social media platform that allows users to post short messages and engage primarily with other nearby users. Study 1 qualitatively examined student uses and perceptions of the app through 12 in-depth interviews with Yik Yak users. Study 2 conducted a content analysis of yaks (N = 3,905) from 24 colleges and universities to gain a better understanding of the content that students post and engage with inside the app. The combination of qualitative and quantitative findings offers insight into the complex phenomena of Yik Yak in a university setting. Limitations and future directions of research are discussed

Cocktails and Brainwaves: Experiments with Complex and Subliminal Auditory Stimuli

The paper deals with the problem of processing acoustic signals originating from multiple sources in a potentially noisy environment. Previous research in speech processing and cognitive modelling has tended to concentrate on single sources and relatively noise free signals. Separating out different signals from a multitude of sources is a significant part of human auditory processing. In speech processing research, the problem we are dealing with is known as the cocktail party syndrome. The processing of polyphonic music involves similar challenges, and auditory scene analysis (ASA) has been proposed as a means of separating out component signals and identifying their sources. In subliminal auditory processing, a speech signal which is masked from conscious awareness by a music signal provides an extreme form of the multiple source problem and permits exploration of the boundary between conscious and unconscious auditory processing. The research presented employs machine learning and associative models to characterize and track individual signals, and uses electroencephalographic (EEG) analysis to more precisely characterize human processing of multimodal signals

Thalamocortical connectivity in major depressive disorder

Background: Major Depressive Disorder (MDD) is highly prevalent and potentially devastating, with widespread aberrations in brain activity. Thalamocortical networks are a potential candidate marker for psychopathology in MDD, but have not yet been thoroughly investigated. Here we examined functional connectivity between major cortical areas and thalamus. Method: Resting-state fMRI from 54 MDD patients and 40 healthy controls were collected. The cortex was segmented into six regions of interest (ROIs) consisting of frontal, temporal, parietal, and occipital lobes and pre-central and post-central gyri. BOLD signal time courses were extracted from each ROI and correlated with voxels in thalamus, while removing signals from every other ROI. Results: Our main findings showed that MDD patients had predominantly increased connectivity between medial thalamus and temporal areas, and between medial thalamus and somatosensory areas. Furthermore, a positive correlation was found between thalamo-temporal connectivity and severity of symptoms. Limitations: Most of the patients in this study were not medication naïve and therefore we cannot rule out possible long-term effects of antidepressant use on the findings. Conclusion: The abnormal connectivity between thalamus and temporal, and thalamus and somatosensory regions may represent impaired cortico-thalamo-cortical modulation underlying emotional, and sensory disturbances in MDD. In the context of similar abnormalities in thalamocortical systems across major psychiatric disorders, thalamocortical dysconnectivity could be a reliable transdiagnostic marker

Virus prevalence and genetic diversity across a wild bumblebee community

Viruses are key population regulators, but we have limited knowledge of the diversity and ecology of viruses. This is even the case in wild host populations that provide ecosystem services, where small fitness effects may have major ecological impacts in aggregate. One such group of hosts are the bumblebees, which have a major role in the pollination of food crops and have suffered population declines and range contractions in recent decades. In this study, we investigate the diversity of four recently discovered bumblebee viruses (Mayfield virus 1, Mayfield virus 2, River Liunaeg virus and Loch Morlich virus), and two previously known viruses that infect both wild bumblebees and managed honeybees (Acute bee paralysis virus and Slow bee paralysis virus) from isolates in Scotland. We investigate the ecological and environmental factors that determine viral presence and absence. We show that the recently discovered bumblebee viruses were more genetically diverse than the viruses shared with honeybees. Coinfection is potentially important in shaping prevalence: we found a strong positive association between River Liunaeg virus and Loch Morlich virus presence after controlling for host species, location and other relevant ecological variables. We tested for a relationship between environmental variables (temperature, UV radiation, wind speed and prevalence), but as we had few sampling sites, and thus low power for site-level analyses, we could not conclude anything regarding these variables. We also describe the relationship between the bumblebee communities at our sampling sites. This study represents a first step in the description of predictors of bumblebee infection in the wild

Strontium and Oxygen Isotope Profiles of Sequentially Sampled Modern Bison (Bison bison bison) Teeth from Interior Alaska as Proxies of Seasonal Mobility

Studies addressing prehistoric mobility in animals typically use isotopic analyses of sequentially formed tissues, such as the growth layers in teeth, to infer physical movement on the landscape. Strontium isotope ratios (87Sr/86Sr values), which vary geographically, are particularly useful for this purpose, especially when paired with stable oxygen isotope ratios (δ18O), which vary seasonally. Together, these two isotope systems can provide information about past animal movement patterns on a seasonal scale. However, while many studies have used 87Sr/86Sr and δ18O values from analyses of sequentially formed tissues for this purpose, there have been limited analyses on modern animals of known movement patterns across high-latitude regions. In this pilot study, we sequentially sampled and analyzed one second molar (M2) and two third molars (M3) from two bison (Bison bison bison) from the Delta bison herd, which resides in interior Alaska and has known and documented seasonal mobility patterns. The resulting 87Sr/86Sr values from the teeth were compared to a high-resolution 87Sr/86Sr isoscape for the region and were paired with δ18O analyses to determine whether the seasonal 87Sr/86Sr values matched the predicted values for each of the seasonal bison habitat areas. The results indicate that the 87Sr/86Sr and δ18O values reliably reflected the known seasonal mobility patterns of bison and suggest that this approach could be used to investigate the mobility patterns of prehistoric bison in Alaska and surrounding high-latitude regions.En général, les études qui portent sur la mobilité des animaux préhistoriques se servent d’analyses isotopiques des tissus séquentiellement formés, y compris les couches de développement des dents, afin d’en déduire les mouvements physiques dans l’environnement. Les rapports isotopiques du strontium (87Sr/86Sr) sont particulièrement utiles à cette fin, car ils varient géographiquement, surtout lorsqu’ils sont jumelés avec les rapports isotopiques stables de l’oxygène (δ18O), dont la variabilité est saisonnière. Ensemble, ces deux isotopes peuvent fournir des informations sur les habitudes de déplacement des animaux dans un paysage en fonction des saisons. Cependant, même si plusieurs études ont utilisé les valeurs 87Sr/86Sr et δ18O découlant des analyses des tissus séquentiellement formés à cette fin, peu d’analyses ont été effectuées chez les animaux modernes dont les habitudes de déplacement sont connues dans les régions de haute latitude. Dans cette étude pilote, nous avons séquentiellement échantillonné et analysé une deuxième molaire (M2) et deux troisièmes molaires (M3) de deux bisons (Bison bison bison) du troupeau de bisons du delta, troupeau qui réside dans l’intérieur de l’Alaska et dont les modèles de mobilité saisonnière sont connus et documentés. Les valeurs 87Sr/86Sr obtenues à partir des dents ont été comparées à un paysage isotopique de haute résolution 87Sr/86Sr pour la région et ont été jumelées aux analyses δ18O pour déterminer si les valeurs 87Sr/86Sr saisonnières correspondaient aux valeurs prévues pour les zones d’habitat saisonnières du bison. Les résultats indiquent que les valeurs 87Sr/86Sr et δ18O reflètent fidèlement les modèles connus de mobilité saisonnière du bison, et suggèrent que cette méthode pourrait servir à étudier les modèles de mobilité des bisons préhistoriques en Alaska et dans les régions de haute latitude environnantes

Et3SiH + KOtBu provide multiple reactive intermediates that compete in the reactions and rearrangements of benzylnitriles and indolenines

The combination of potassium tert-butoxide and triethylsilane is unusual because it generates multiple different types of reactive intermediates simultaneously that provide access to (i) silyl radical reactions, (ii) hydrogen atom transfer reactions to closed shell molecules and to radicals, (iii) electron transfer reductions and (iv) hydride ion chemistry, giving scope for unprecedented outcomes. Until now, reactions with this reagent pair have generally been explained by reference to one of the intermediates, but we now highlight the interplay and competition between them

Ocean acidification with (de)eutrophication will alter future phytoplankton growth and succession

Human activity causes ocean acidification (OA) though the dissolution of anthropogenically generated CO2 into seawater, and eutrophication through the addition of inorganic nutrients. Eutrophication increases the phytoplankton biomass that can be supported during a bloom, and the resultant uptake of dissolved inorganic carbon during photosynthesis increases water-column pH (bloom-induced basification). This increased pH can adversely affect plankton growth. With OA, basification commences at a lower pH. Using experimental analyses of the growth of three contrasting phytoplankton under different pH scenarios, coupled with mathematical models describing growth and death as functions of pH and nutrient status, we show how different conditions of pH modify the scope for competitive interactions between phytoplankton species. We then use the models previously configured against experimental data to explore how the commencement of bloom-induced basification at lower pH with OA, and operating against a background of changing patterns in nutrient loads, may modify phytoplankton growth and competition. We conclude that OA and changed nutrient supply into shelf seas with eutrophication or de-eutrophication (the latter owing to pollution control) has clear scope to alter phytoplankton succession, thus affecting future trophic dynamics and impacting both biogeochemical cycling and fisheries

Urban meadows as an alternative to short mown grassland: Effects of composition and height on biodiversity

There are increasing calls to provide greenspace in urban areas, yet the ecological quality, as well as quantity, of greenspace is important. Short mown grassland designed for recreational use is the dominant form of urban greenspace in temperate regions but requires considerable maintenance and typically provides limited habitat value for most taxa. Alternatives are increasingly proposed, but the biodiversity potential of these is not well understood. In a replicated experiment across six public urban greenspaces we used nine different perennial meadow plantings to quantify the relative roles of floristic diversity and height of sown meadows on the richness and composition of three taxonomic groups – plants, invertebrates and soil microbes. We found that all meadow treatments were colonised by plant species not sown in the plots, suggesting that establishing sown meadows does not preclude further locally determined grassland development if management is appropriate. Colonising species were rarer in taller and more diverse plots, indicating competition may limit invasion rates. Urban meadow treatments contained invertebrate and microbial communities that differed from mown grassland. Invertebrate taxa responded to changes in both height and richness of meadow vegetation, but most orders were more abundant where vegetation height was longer than mown grassland. Order richness also increased in longer vegetation and Coleoptera family richness increased with plant diversity in summer. Microbial community composition seems sensitive to plant species composition at the soil surface (0–10 cm), but in deeper soils (11–20 cm) community variation was most responsive to plant height, with bacteria and fungi responding differently. In addition to improving local residents’ satisfaction, native perennial meadow plantings can produce biologically diverse grasslands that support richer and more abundant invertebrate communities, and restructured plant, invertebrate and soil microbial communities compared with short mown grassland. Our results suggest that diversification of urban greenspace by planting urban meadows in place of some mown amenity grassland is likely to generate substantial biodiversity benefits, with a mosaic of meadow types likely to maximise such benefits

MSH3 polymorphisms and protein levels affect CAG repeat instability in huntington's disease mice

Expansions of trinucleotide CAG/CTG repeats in somatic tissues are thought to contribute to ongoing disease progression through an affected individual's life with Huntington's disease or myotonic dystrophy. Broad ranges of repeat instability arise between individuals with expanded repeats, suggesting the existence of modifiers of repeat instability. Mice with expanded CAG/CTG repeats show variable levels of instability depending upon mouse strain. However, to date the genetic modifiers underlying these differences have not been identified. We show that in liver and striatum the R6/1 Huntington's disease (HD) (CAG)~100 transgene, when present in a congenic C57BL/6J (B6) background, incurred expansion-biased repeat mutations, whereas the repeat was stable in a congenic BALB/cByJ (CBy) background. Reciprocal congenic mice revealed the Msh3 gene as the determinant for the differences in repeat instability. Expansion bias was observed in congenic mice homozygous for the B6 Msh3 gene on a CBy background, while the CAG tract was stabilized in congenics homozygous for the CBy Msh3 gene on a B6 background. The CAG stabilization was as dramatic as genetic deficiency of Msh2. The B6 and CBy Msh3 genes had identical promoters but differed in coding regions and showed strikingly different protein levels. B6 MSH3 variant protein is highly expressed and associated with CAG expansions, while the CBy MSH3 variant protein is expressed at barely detectable levels, associating with CAG stability. The DHFR protein, which is divergently transcribed from a promoter shared by the Msh3 gene, did not show varied levels between mouse strains. Thus, naturally occurring MSH3 protein polymorphisms are modifiers of CAG repeat instability, likely through variable MSH3 protein stability. Since evidence supports that somatic CAG instability is a modifier and predictor of disease, our data are consistent with the hypothesis that variable levels of CAG instability associated with polymorphisms of DNA repair genes may have prognostic implications for various repeat-associated diseases