Cloud classrooms provide many advantages in higher education. However, little is known about the social influence of peer relationships on students’ acceptance of cloud classrooms. This study ...utilized structural equation modeling to examine a model that integrates the Universal Theory of Acceptance and Use of Technology (UTAUT) and Connected Classroom Climate (CCC). Effort expectancy, social influence, and CCC were found to significantly impact cloud classroom acceptance by college students. Performance expectancy and facilitating conditions, however, did not affect acceptance. These findings contribute understanding that can support decision-making for the cloud classroom, with particular emphasis on increasing college students’ acceptance and use of such technology. Administrators, researchers, and practitioners can use this knowledge to guide their implementation, improvement, and assessment of cloud classrooms. In addition, beyond the cloud classroom, our identification of this relationship between CCC and students’ acceptance represents new knowledge to guide other contexts of online learning.
Are exoplanetesimals differentiated? Bonsor, Amy; Carter, Philip J; Hollands, Mark ...
Monthly notices of the Royal Astronomical Society,
02/2020, Letnik:
492, Številka:
2
Journal Article
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ABSTRACT
Metals observed in the atmospheres of white dwarfs suggest that many have recently accreted planetary bodies. In some cases, the compositions observed suggest the accretion of material ...dominantly from the core (or the mantle) of a differentiated planetary body. Collisions between differentiated exoplanetesimalrrs produce such fragments. In this work, we take advantage of the large numbers of white dwarfs where at least one siderophile (core-loving) and one lithophile (rock-loving) species have been detected to assess how commonly exoplanetesimals differentiate. We utilize N-body simulations that track the fate of core and mantle material during the collisional evolution of planetary systems to show that most remnants of differentiated planetesimals retain core fractions similar to their parents, while some are extremely core rich or mantle rich. Comparison with the white dwarf data for calcium and iron indicates that the data are consistent with a model in which $66^{+4}_{-6}{{\ \rm per\ cent}}$ have accreted the remnants of differentiated planetesimals, while $31^{+5}_{-5}{{\ \rm per\ cent}}$ have Ca/Fe abundances altered by the effects of heating (although the former can be as high as $100{{\ \rm per\ cent}}$, if heating is ignored). These conclusions assume pollution by a single body and that collisional evolution retains similar features across diverse planetary systems. These results imply that both collisions and differentiation are key processes in exoplanetary systems. We highlight the need for a larger sample of polluted white dwarfs with precisely determined metal abundances to better understand the process of differentiation in exoplanetary systems.
BackgroundChanges in invasive pneumococcal disease (IPD) incidence were evaluated after 7 years of 7-valent pneumococcal conjugate vaccine (PCV7) use in US children MethodsLaboratory-confirmed IPD ...cases were identified during 1998–2007 by 8 active population-based surveillance sites. We compared overall, age group-specific, syndrome-specific, and serotype group-specific IPD incidence in 2007 with that in 1998–1999 (before PCV7) and assessed potential serotype coverage of new conjugate vaccine formulations ResultsOverall and PCV7-type IPD incidence declined by 45% (from 24.4 to 13.5 cases per 100,000 population) and 94% (from 15.5 to 1.0 cases per 100,000 population), respectively (P<.01 for all age groups). The incidence of IPD caused by serotype 19A and other non-PCV7 types increased from 0.8 to 2.7 cases per 100,000 population and from 6.1 to 7.9 cases per 100,000 population, respectively (P<.01 for all age groups). The rates of meningitis and invasive pneumonia caused by non-PCV7 types increased for all age groups (P<.05), whereas the rates of primary bacteremia caused by these serotypes did not change. In 2006–2007, PCV7 types caused 2% of IPD cases, and the 6 additional serotypes included in an investigational 13-valent conjugate vaccine caused 63% of IPD cases among children <5 years-old ConclusionsDramatic reductions in IPD after PCV7 introduction in the United States remain evident 7 years later. IPD rates caused by serotype 19A and other non-PCV7 types have increased but remain low relative to decreases in PCV7-type IPD
Background. Widespread use of pneumococcal conjugate vaccine (PCV7) resulted in decreases in invasive disease among children and elderly persons. The benefits may be offset by increases in disease ...due to serotypes not included in the vaccine (hereafter, "nonvaccine serotypes"). We evaluated the effect of PCV7 on incidence of disease due to nonvaccine serotypes. Methods. Cases of invasive disease were identified in 8 geographic areas through the Centers for Disease Control and Prevention's Active Bacterial Core surveillance. Serotyping and susceptibility testing of isolates were performed. We calculated the incidence of disease for children aged <5 years and adults aged ⩾65 years. We compared rates of serotype-specific disease before and after PCV7 was licensed for use. Results. The annual incidence of disease due to nonvaccine serotypes increased from an average of 16.3 cases/100,000 population during prevaccine years (1998–1999) to 19.9 cases/100,000 population in 2004 for children aged <5 years (P=.01) and from 27.0 cases/100,000 population during prevaccine years to 29.8 cases/100,000 population in 2004 for adults aged ⩾65 years (P=.05). Significant increases in the incidences of disease due to serotypes 3, 15, 19A, 22F, and 33F were observed among children during this period (P<.05 for each serotype); serotype 19A has become the predominant cause of invasive disease in children. The incidence of disease due to these serotypes also increased among elderly persons. Conclusions. The incidence of pneumococcal disease caused by nonvaccine serotypes is increasing. Ongoing surveillance is needed to monitor the magnitude of disease caused by nonvaccine serotypes, to ensure that future vaccines target the appropriate serotypes.
Principal component analysis (PCA) is possibly one of the most widely used statistical tools to recover a low-rank structure of the data. In the highdimensional settings, the leading eigenvector of ...the sample covariance can be nearly orthogonal to the true eigenvector. A sparse structure is then commonly assumed along with a low rank structure. Recently, minimax estimation rates of sparse PCA were established under various interesting settings. On the other side, Bayesian methods are becoming more and more popular in high-dimensional estimation, but there is little work to connect frequentisi properties and Bayesian methodologies for high-dimensional data analysis. In this paper, we propose a prior for the sparse PCA problem and analyze its theoretical properties. The prior adapts to both sparsity and rank. The posterior distribution is shown to contract to the truth at optimal minimax rates. In addition, a computationally efficient strategy for the rank-one case is discussed.
Metabotropic glutamate receptor 7 (mGlu
) is the most highly conserved and abundantly expressed mGlu receptor in the human brain. The presynaptic localization of mGlu
, coupled with its low affinity ...for its endogenous agonist, glutamate, are features that contribute to the receptor's role in modulating neuronal excitation and inhibition patterns, including long-term potentiation, in various brain regions. These characteristics suggest that mGlu
modulation may serve as a novel therapeutic strategy in disorders of cognitive dysfunction, including neurodevelopmental disorders that cause impairments in learning, memory, and attention. Primary mutations in the
gene have recently been identified as novel causes of neurodevelopmental disorders, and these patients exhibit profound intellectual and cognitive disability. Pharmacological tools, such as agonists, antagonists, and allosteric modulators, have been the mainstay for targeting mGlu
in its endogenous homodimeric form to probe effects of its function and modulation in disease models. However, recent research has identified diversity in dimerization, as well as trans-synaptic interacting proteins, that also play a role in mGlu
signaling and pharmacological properties. These novel findings represent exciting opportunities in the field of mGlu receptor drug discovery and highlight the importance of further understanding the functions of mGlu
in complex neurologic conditions at both the molecular and physiologic levels. SIGNIFICANCE STATEMENT: Proper expression and function of mGlu
is essential for learning, attention, and memory formation at the molecular level within neural circuits. The pharmacological targeting of mGlu
is undergoing a paradigm shift by incorporating an understanding of receptor interaction with other
and
acting synaptic proteins, as well as various intracellular signaling pathways. Based upon these new findings, mGlu
's potential as a drug target in the treatment of cognitive disorders and learning impairments is primed for exploration.
Background. Invasive group A Streptococcus (GAS) infections are associated with significant morbidity and mortality rates. We report the epidemiology and trends of invasive GAS over 8 years of ...surveillance. Methods. From January 2005 through December 2012, we collected data from the Centers for Disease Control and Prevention's Active Bacterial Core surveillance, a population-based network of 10 geographically diverse US sites (2012 population, 32.8 million). We defined invasive GAS as isolation of GAS from a normally sterile site or from a wound in a patient with necrotizing fasciitis (NF) or streptococcal toxic shock syndrome (STSS). Available isolates were emm typed. We calculated rates and made age- and race-adjusted national projections using census data. Results. We identified 9557 cases (3.8 cases per 100 000 persons per year) with 1116 deaths (case-fatality rate, 11.7%). The case-fatality rates for septic shock, STSS, and NF were 45%, 38%, and 29%, respectively. The annual incidence was highest among persons aged ≥65 years (9.4/100 000) or <1 year (5.3) and among blacks (4.7/100 000). National rates remained steady over 8 years of surveillance. Factors independently associated with death included increasing age, residence in a nursing home, recent surgery, septic shock, NF, meningitis, isolated bacteremia, pneumonia, emm type 1 or 3, and underlying chronic illness or immunosuppression. An estimated 10 649–13 434 cases of invasive GAS infections occur in the United States annually, resulting in 1136–1607 deaths. In a 30-valent M-protein vaccine, emm types accounted for 91% of isolates. Conclusions. The burden of invasive GAS infection in the United States remains substantial. Vaccines under development could have a considerable public health impact.
Many organizations rely on group work to generate creativity, but existing research lacks theory on how groups’ responses to recognition for creative achievement shape their subsequent creative ...outcomes. Through an inductive study of bands nominated for a Best New Artist Grammy from 1980 to 1990, we develop a theory of reactions to early recognition in creative groups. Our multi-method analyses include oral histories from members of each band and quantitative data, which we use to triangulate the processes they describe. Our findings reveal that groups developed sets of emergent reactions and active adjustments to the recognition and its consequences, which we call “recognition orientations.” We identify three such orientations—absorbing, insulating, and mixed—that reflect how groups interpret recognition and integrate it into their subsequent processes. Most groups struggled by absorbing recognition, which led to internalizing expectations and opening their relationships to outsiders, ultimately inhibiting creativity. Some groups began to insulate themselves from recognition by externalizing expectations and bounding relationships, allowing them to sustain creative output over time. Finally, other groups developed a mixed orientation, initially experiencing the pitfalls of elevated recognition-seeking but ultimately attempting to insulate their need for external recognition by refocusing on their creative process. These findings reveal that recognition can upend the creative process, and groups that begin absorbing recognition are, ironically, less likely to earn it again in the future. Filling a critical research gap on creative production among groups that intend to continue working together, the results distinguish the skills needed to manage recognition from those needed to generate creativity, and offer insight into how groups enact longevity.
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