On Online Engagement: Does the Leadership Style Matter?

The news industry is facing tremendous changes. Integrating digital technologies into news practices has become the key to survival. Social media engagement editors are one of such innovations to respond to the challenge. Engagement editors are required to facilitate the functions of marketing, editing, content production, and data analysis. They thus play the role of boundary-spanner within and beyond the organizational boundaries. However, there are few studies to explore issues associated with the management of social media engagement editors. This research examines whether and how the leadership style (i.e., transformational and passive leadership style) influences engagement editors’ job performance. We collected 122 valid responses, and used the SmartPLS 3 and SPSS 19.0 to analyze the data. Our findings indicate that performance of engagement editors is influenced by the leadership style; moreover, job autonomy mediates the positive effect of transformational leadership on engagement editors’ job performance. Implications for the management of social media engagement editors are discussed

DFB Quantum Cascade Laser Arrays

DFB quantum cascade laser (DFB-QCL) arrays operating between 8.7 and 9.4 mum are investigated for their performance characteristics-single-mode selection of the DFB grating, and variability in threshold, slope efficiency, and output power of different lasers in the array. Single-mode selection refers to the ability to choose a desired mode/frequency of laser emission with a DFB grating. We apply a theoretical framework developed for general DFB gratings to analyze DFB-QCL arrays. We calculate how the performance characteristics of DFB-QCLs are affected by the coupling strength kappaL of the grating, and the relative position of the mirror facets at the ends of the laser cavity with respect to the grating. We discuss how single-mode selection can be improved by design. Several DFB-QCL arrays are fabricated and their performance examined. We achieve desired improvements in single-mode selection, and we observe the predicted variability in the threshold, slope efficiency, and output power of the DFB-QCLs. As a demonstration of potential applications, the DFB-QCL arrays are used to perform infrared absorption spectroscopy with fluids.Engineering and Applied Science

Impact of Ivacaftor on Medication Use, Hospital and Outpatient Provider Visits and Associated Costs in a Medicaid Population

BACKGROUND: Ivacaftor is the first Food and Drug Administration-approved medication to treat an underlying genetic defect in patients with cystic fibrosis (CF). With an approximate annual cost of $300,000 per patient, ivacaftor may have a profound financial impact on health systems, even when utilized by a small population. Clinical data has demonstrated that treatment with ivacaftor may reduce pulmonary exacerbations (PE) and associated hospitalizations. As a result, patients receiving ivacaftor may need less outpatient care and fewer medications to treat CF complications. Evaluating the impact of ivacaftor therapy on medication utilization, PEs and hospital/outpatient visits can aid formulary decision makers in its effective management. OBJECTIVES: The primary objective is to examine the effects of ivacaftor on patients’ overall medication regimen and associated costs within a Medicaid population. The secondary objective is to examine its effect on the rates of PEs and hospital/outpatient visits. METHODS: Pharmacy and medical claims data for Medicaid members ≥ six years of age was collected for six months before and after the first reported pharmacy claim of ivacaftor. Data included: total number of unique claims, days supply, dose, and total cost for each medication, number of short-term antibiotic and/or steroid courses, outpatient provider visits, hospitalizations, ER visits and corresponding diagnosis codes. Diagnosis codes and short-term antibiotic and/or steroid courses were reviewed to determine if a PE may have occurred. RESULTS: Ivacaftor treatment did not decrease the utilization of medications used to treat patients with CF and resulted in increased pharmacy expenditures for other medications. However, a 65% reduction in PEs as well as a reduction in hospitalizations/ER visits was observed in members receiving ivacaftor. CONCLUSIONS: This study found that while ivacaftor treatment may not decrease total medication utilization or associated costs, it may decrease the number of PEs and associated hospitalizations in patients with CF

Acidithiobacillus thiooxidans secretome containing a newly described lipoprotein Licanantase enhances chalcopyrite bioleaching rate

The nature of the mineral–bacteria interphase where electron and mass transfer processes occur is a key element of the bioleaching processes of sulfide minerals. This interphase is composed of proteins, metabolites, and other compounds embedded in extracellular polymeric substances mainly consisting of sugars and lipids (Gehrke et al., Appl Environ Microbiol 64(7):2743–2747, 1998). On this respect, despite Acidithiobacilli—a ubiquitous bacterial genera in bioleaching processes (Rawlings, Microb Cell Fact 4(1):13, 2005)—has long been recognized as secreting bacteria (Jones and Starkey, J Bacteriol 82:788–789, 1961; Schaeffer and Umbreit, J Bacteriol 85:492–493, 1963), few studies have been carried out in order to clarify the nature and the role of the secreted protein component: the secretome. This work characterizes for the first time the sulfur (meta)secretome of Acidithiobacillus thiooxidans strain DSM 17318 in pure and mixed cultures with Acidithiobacillus ferrooxidans DSM 16786, identifying the major component of these secreted fractions as a single lipoprotein named here as Licanantase. Bioleaching assays with the addition of Licanantase-enriched concentrated secretome fractions show that this newly found lipoprotein as an active protein additive exerts an increasing effect on chalcopyrite bioleaching rate

Importance of B4 medium in determining organomineralization potential of bacterial environmental isolates

B4 precipitation medium has been used as the preferred medium for studying mineral precipitation using bacterial strains in vitro since pioneer studies were performed by Boquet and coworkers in 1973. Using this medium, several authors have demonstrated that some environmental isolates were able to precipitate minerals, yet others did not. The main goal of the current study is to understand whether pH and buffer conditions would have a significant effect on mineral precipitation results for environmental isolates grown on B4. For this study, a total of 49 strains isolated from natural environments from Puerto Rico were grown on B4 plates, and their CaCO3 precipitation potential was investigated. Our findings revealed a strong correlation between a lack of CaCO3 precipitation and the acidification of the B4 plates by the colonies. The ability to precipitate CaCO3 could be restored by buffering the B4 medium to a pH of 8.2. Buffering capacity of the medium was proposed to be involved in CaCO3 precipitation: acid-base titrations conducted on the individual ingredients of B4 showed that yeast extract has a poor buffering capacity between pH 6.5?7.5. This pH range corresponds to the pH of B4 plates 6.87 (�±0.05)] prior to the inoculation. This might explain why B4 is such a good precipitation medium: a small variation in the H+/OH? balance during microbial growth and precipitation produces rapid changes in the pH of the medium. Finally, an amorphous matrix was distributed within 90% of the examined crystals generated on B4 medium by the environmental strains. Supplemental materials are available for this article. Go to the publisher's online edition of Geomicrobiology Journal to view the free supplemental file.; B4 precipitation medium has been used as the preferred medium for studying mineral precipitation using bacterial strains in vitro since pioneer studies were performed by Boquet and coworkers in 1973. Using this medium, several authors have demonstrated that some environmental isolates were able to precipitate minerals, yet others did not. The main goal of the current study is to understand whether pH and buffer conditions would have a significant effect on mineral precipitation results for environmental isolates grown on B4. For this study, a total of 49 strains isolated from natural environments from Puerto Rico were grown on B4 plates, and their CaCO3 precipitation potential was investigated. Our findings revealed a strong correlation between a lack of CaCO3 precipitation and the acidification of the B4 plates by the colonies. The ability to precipitate CaCO3 could be restored by buffering the B4 medium to a pH of 8.2. Buffering capacity of the medium was proposed to be involved in CaCO3 precipitation: acid-base titrations conducted on the individual ingredients of B4 showed that yeast extract has a poor buffering capacity between pH 6.5?7.5. This pH range corresponds to the pH of B4 plates 6.87 (�±0.05)] prior to the inoculation. This might explain why B4 is such a good precipitation medium: a small variation in the H+/OH? balance during microbial growth and precipitation produces rapid changes in the pH of the medium. Finally, an amorphous matrix was distributed within 90% of the examined crystals generated on B4 medium by the environmental strains. Supplemental materials are available for this article. Go to the publisher's online edition of Geomicrobiology Journal to view the free supplemental file

Lack of association between PCK1 polymorphisms and obesity, physical activity, and fitness in European Youth Heart Study (EYHS)

Phosphoenolpyruvate carboxykinase-1 (PCK1) is the rate-limiting enzyme in the hepatic gluconeogenic pathway. Studies have shown that overexpression of Pck1 in mice results in obesity-related traits and higher levels of physical activity (PA). Therefore, our aims were to investigate whether common genetic variation in the PCK1 gene influences obesity-related traits, PA, and fitness, and to examine whether PA and fitness attenuate the influence of the PCK1 polymorphisms on obesity in children. Analyses were undertaken on data from Danish and Estonian children (958 boys and 1,104 girls) from the European Youth Heart Study (EYHS), a school-based, cross-sectional study of children (mean ± s.d. age: 9.6 ± 0.4 years) and adolescents (15.5 ± 0.5 years). We genotyped eight polymorphisms that captured the common genetic variations in the PCK1 gene. The association between the PCK1 polymorphisms and BMI, waist circumference (WC), sum of four skinfolds, PA, and fitness was tested using an additive model adjusted for age, age-group, gender, maturity, and country. Interactions were tested by including interaction terms in the model. None of the polymorphisms were significantly associated with BMI, WC, sum of four skinfolds, PA, and fitness, and also with the risk of being overweight or obese (P > 0.05). The interactions between the polymorphisms and age-group, gender, PA, and fitness were not statistically significant. This is the first study to comprehensively examine the association of PCK1 polymorphisms with obesity, PA, and fitness. Despite strong evidence from animal studies, our study in the EYHS cohort failed to identify an association of PCK1 polymorphisms with obesity, PA, and fitness

Fermi Large Area Telescope Constraints on the Gamma-ray Opacity of the Universe

The Extragalactic Background Light (EBL) includes photons with wavelengths from ultraviolet to infrared, which are effective at attenuating gamma rays with energy above ~10 GeV during propagation from sources at cosmological distances. This results in a redshift- and energy-dependent attenuation of the gamma-ray flux of extragalactic sources such as blazars and Gamma-Ray Bursts (GRBs). The Large Area Telescope onboard Fermi detects a sample of gamma-ray blazars with redshift up to z~3, and GRBs with redshift up to z~4.3. Using photons above 10 GeV collected by Fermi over more than one year of observations for these sources, we investigate the effect of gamma-ray flux attenuation by the EBL. We place upper limits on the gamma-ray opacity of the Universe at various energies and redshifts, and compare this with predictions from well-known EBL models. We find that an EBL intensity in the optical-ultraviolet wavelengths as great as predicted by the "baseline" model of Stecker et al. (2006) can be ruled out with high confidence.Comment: 42 pages, 12 figures, accepted version (24 Aug.2010) for publication in ApJ; Contact authors: A. Bouvier, A. Chen, S. Raino, S. Razzaque, A. Reimer, L.C. Reye

Mammalian Kinesin-3 Motors Are Dimeric In Vivo and Move by Processive Motility upon Release of Autoinhibition

Kinesin-3 motors drive the transport of synaptic vesicles and other membrane-bound organelles in neuronal cells. In the absence of cargo, kinesin motors are kept inactive to prevent motility and ATP hydrolysis. Current models state that the Kinesin-3 motor KIF1A is monomeric in the inactive state and that activation results from concentration-driven dimerization on the cargo membrane. To test this model, we have examined the activity and dimerization state of KIF1A. Unexpectedly, we found that both native and expressed proteins are dimeric in the inactive state. Thus, KIF1A motors are not activated by cargo-induced dimerization. Rather, we show that KIF1A motors are autoinhibited by two distinct inhibitory mechanisms, suggesting a simple model for activation of dimeric KIF1A motors by cargo binding. Successive truncations result in monomeric and dimeric motors that can undergo one-dimensional diffusion along the microtubule lattice. However, only dimeric motors undergo ATP-dependent processive motility. Thus, KIF1A may be uniquely suited to use both diffuse and processive motility to drive long-distance transport in neuronal cells

Israeli Acute Paralysis Virus: Epidemiology, Pathogenesis and Implications for Honey Bee Health

Israeli acute paralysis virus (IAPV) is a widespread RNA virus of honey bees that has been linked with colony losses. Here we describe the transmission, prevalence, and genetic traits of this virus, along with host transcriptional responses to infections. Further, we present RNAi-based strategies for limiting an important mechanism used by IAPV to subvert host defenses. Our study shows that IAPV is established as a persistent infection in honey bee populations, likely enabled by both horizontal and vertical transmission pathways. The phenotypic differences in pathology among different strains of IAPV found globally may be due to high levels of standing genetic variation. Microarray profiles of host responses to IAPV infection revealed that mitochondrial function is the most significantly affected biological process, suggesting that viral infection causes significant disturbance in energy-related host processes. The expression of genes involved in immune pathways in adult bees indicates that IAPV infection triggers active immune responses. The evidence that silencing an IAPV-encoded putative suppressor of RNAi reduces IAPV replication suggests a functional assignment for a particular genomic region of IAPV and closely related viruses from the Family Dicistroviridae, and indicates a novel therapeutic strategy for limiting multiple honey bee viruses simultaneously and reducing colony losses due to viral diseases. We believe that the knowledge and insights gained from this study will provide a new platform for continuing studies of the IAPV–host interactions and have positive implications for disease management that will lead to mitigation of escalating honey bee colony losses worldwide