Leadership styles and behaviors of African American women executives from different economic centers

The leadership styles and behaviors of African American women executives across multiple economic sectors were studied using an explanatory sequential mixed methods approach. Senior leaders from six of the following sectors Academia, Business, Government, Law, Military, and Nonprofit were surveyed using the Multifactor Leadership Questionnaire (MLQ) to quantitatively assess their leadership styles and behaviors. A subset of survey respondents from each sector were interviewed one-on-one to provide contextual details regarding their MLQ results, and to elicit additional perspectives on leadership styles in general and the development of their individual style in particular. The preponderance of the relatively limited published studies on the leadership attributes of African American women have involved one or more of the following design methodologies: (a) use of qualitative methods, (b) focus on a single sector of the economy, (c) inclusion of a range of leadership positions from middle to senior management within their sample size, and (d) exploration of the obstacles and barriers encountered by the women during their journey to leadership. The purpose of the present research augmented the scope and results of the previous work. MLQ data from a numerically significant sample of executives, coupled with the interview narratives, potentially provided the necessary quantitative and qualitative underpinnings to support and/or reshape findings from the past studies. Expanding the scope to include leaders from different sectors furnished insight into potential sector-specific influences on leadership styles; and tightening of the sampling process to include only senior-level leaders in organizations reduced experimental variability and insured a pool of participants with extensive leadership experience. The obstacles and barriers facing African American women leaders received the most attention in prior studies and therefore is not a key focus of this work. However, salient information gleaned from interviews concerning their impact on leadership styles have been reported. It is expected that the data and information from this study has yielded a more comprehensive evaluation of the leadership styles and behaviors of these African American women executives in particular, and potentially enabled meaningful comparisons with previously published findings on such leadership characteristics in general

Structural and Biochemical Characterization of the Frequency-Interacting RNA Helicase FRH

RNA is a molecular messenger of the cell, essential to many cellular pathways and processes. In order to maintain functionality, RNA is processed and modified by protein complexes such as the exosome and associated proteins. The exosome-mediated RNA processing or degradation both require a Ski-2 like helicase to function. One such helicase is the Frequency-interacting RNA Helicase (FRH), an essential RNA helicase from Neurospora Crassa. FRH is homologous to the Saccharomyces cerevisiae Mtr4 from the Ski2-like family of RNA helicases. Sequence alignments between FRH and Ski2-like family helicases predicted FRH to share the helicase core domains and the inserted arch domain a characteristic of the Mtr4-like proteins in this protein family. FRH is also a main component of the circadian oscillation pathway in N. crassa. The participation of FRH in circadian oscillation is not a shared role across RNA helicases. FRH forms a link between two major cellular pathways providing a unique system to study RNA surveillance. Here we present the 3.51Å and 3.25Å crystal structures of FRH which supports structural prediction by maintaining the core architecture found in Ski2-like helicases. These similarities are accompanied by significant flexibility of the arch domain and revealed a unique homodimer. Other known Ski2-like helicases have not been observed to form dimers and function biologically as monomers. Furthermore, the initial characterization of helicase activity of FRH on a poly-adenylated RNA substrate is presented. Also explored is the evidence of a dimer through crosslinking and size exclusion chromatography assays

Effective Prevention of Adolescent Substance Abuse – Educational versus Deterrent Approaches

Substance abuse, especially among adolescents, has long been an important issue in society. In light of the adverse impact of substance abuse, scholars, educators, and policy-makers have proposed different approaches to prevent and reduce such abuse. This paper investigates the effectiveness of the two prominent approaches—educational and deterrent—in preventing and reducing adolescent substance abuse. The educational approach (e.g., school-based prevention programming) tends to be more comprehensive and better grounded in theories than the deterrent approach (e.g., drug testing). The educational approach not only targets multiple psychosocial factors contributing to substance abuse, but it is also supported by empirical studies showing that school-based prevention programming is effective in preventing substance abuse and has long-lasting positive influences on adolescent development. Practical implications of implementing school-based prevention programming are also discussed. L'abus d'alcool ou d'autres drogues, surtout chez les adolescents, constitue depuis longtemps une préoccupation importante de la société. À la lumière de l'impact défavorable de cet abus, les chercheurs, enseignants et décideurs ont proposé différentes approches pour le prévenir et le limiter. Cet article porte sur l'efficacité de deux approches importantes, l'une pédagogique, l'autre dissuasive, visant la prévention et la réduction de l'abus d'alcool ou d'autres drogues chez les adolescents. L'approche pédagogique (par ex. les programmes de prévention en milieu scolaire) est, de façon générale, plus globale et mieux fondée sur les théories que l'approche dissuasive (par ex. dépistage des drogues). Non seulement l'approche pédagogique cible-t-elle les divers facteurs psychosociaux qui contribuent à cet abus, elle est de plus appuyée par des études empiriques indiquant que les programmes de prévention en milieu scolaire sont des outils efficaces dans la prévention de l'abus d'alcool ou d'autres drogues et qu'ils ont un impact positif à long terme sur le développement des adolescents. Nous discutons des répercussions pratiques de la mise en œuvre des programmes de prévention en milieu scolaire

Structure of Frequency-Interacting RNA Helicase from \u3ci\u3eNeurospora crassa\u3c/i\u3e Reveals High Flexibility in a Domain Critical for Circadian Rhythm and RNA Surveillance

The FRH (frequency-interacting RNA helicase) protein is the Neurospora crassa homolog of yeast Mtr4, an essential RNA helicase that plays a central role in RNA metabolism as an activator of the nuclear RNA exosome. FRH is also a required component of the circadian clock, mediating protein interactions that result in the rhythmic repression of gene expression. Here we show that FRH unwinds RNA substrates in vitro with a kinetic profile similar to Mtr4, indicating that while FRH has acquired additional functionality, its core helicase function remains intact. In contrast with the earlier FRH structures, a new crystal form of FRH results in an ATP binding site that is undisturbed by crystal contacts and adopts a conformation consistent with nucleotide binding and hydrolysis. Strikingly, this new FRH structure adopts an arch domain conformation that is dramatically altered from previous structures. Comparison of the existing FRH structures reveals conserved hinge points that appear to facilitate arch motion. Regions in the arch have been previously shown to mediate a variety of protein-protein interactions critical for RNA surveillance and circadian clock functions. The conformational changes highlighted in the FRH structures provide a platform for investigating the relationship between arch dynamics and Mtr4/FRH function

Expression of neurogenin3 reveals an islet cell precursor population in the pancreas

Differentiation of early gut endoderm cells into the endocrine cells forming the pancreatic islets of Langerhans depends on a cascade of gene activation events controlled by transcription factors including the basic helix-loop-helix (bHLH) proteins. To delineate this cascade, we began by establishing the position of neurogenin3, a bHLH factor found in the pancreas during fetal development. We detect neurogenin3 immunoreactivity transiently in scattered ductal cells in the fetal mouse pancreas, peaking at embryonic day 15.5. Although not detected in cells expressing islet hormones or the islet transcription factors Isl1, Brn4, Pax6 or PDX1, neurogenin3 is detected along with early islet differentiation factors Nkx6.1 and Nkx2.2, establishing that it is expressed in immature cells in the islet lineage. Analysis of transcription factor-deficient mice demonstrates that neurogenin3 expression is not dependent on neuroD1/BETA2, Mash1, Nkx2.2, Nkx6.1, or Pax6. Furthermore, early expression of neurogenin3 under control of the Pdx1 promoter is alone sufficient to drive early and ectopic differentiation of islet cells, a capability shared by the pancreatic bHLH factor, neuroD1/BETA2, but not by the muscle bHLH factor, MyoD. However, the islet cells produced in these transgenic experiments are overwhelmingly α cells, suggesting that factors other than the bHLH factors are required to deviate from a default α cell fate. These data support a model in which neurogenin3 acts upstream of other islet differentiation factors, initiating the differentiation of endocrine cells, but switching off prior to final differentiation. The ability to uniquely identify islet cell precursors by neurogenin3 expression allows us to determine the position of other islet transcription factors in the differentiation cascade and to propose a map for the islet cell differentiation pathway

Distinction of disorder, classical and quantum vibrational contributions to atomic mean-square amplitudes in dielectric pentachloronitrobenzene

The solid-state molecular disorder of pentachloronitrobenzene (PCNB) and its role in causing anomalous dielectric properties are investigated. Normal coordinate analysis (NCA) of atomic mean-square displacement parameters (ADPs) is employed to distinguish disorder contributions from classical and quantum-mechanical vibrational contributions. The analysis relies on multitemperature (5-295 K) single-crystal neutron-diffraction data. Vibrational frequencies extracted from the temperature dependence of the ADPs are in good agreement with THz spectroscopic data. Aspects of the static disorder revealed by this work, primarily tilting and displacement of the molecules, are compared with corresponding results from previous, much more in-depth and time-consuming Monte Carlo simulations; their salient findings are reproduced by this work, demonstrating that the faster NCA approach provides reliable constraints for the interpretation of diffuse scattering. The dielectric properties of PCNB can thus be rationalized by an interpretation of the temperature-dependent ADPs in terms of thermal motion and molecular disorder. The use of atomic displacement parameters in the NCA approach is nonetheless hostage to reliable neutron data. The success of this study demonstrates that state-of-the-art single-crystal Laue neutron diffraction affords sufficiently fast the accurate data for this type of study. In general terms, the validation of this work opens up the field for numerous studies of solid-state molecular disorder in organic materials.Comment: Now published in Physical Review

Structure of a Bovine Thrombin-Hirudin\u3csub\u3e51-65\u3c/sub\u3e Complex Determined by a Combination of Molecular Replacement and Graphics. Incorporation of Known Structural Information in Molecular Replacement

Crystals of the bovine thrombin-hirudins51-65 complex have space group P6122 with cell constants a = 116.4, and c = 200.6 Å and two thrombin molecules in the asymmetric unit. Only one thrombin molecule could be located by generalized molecular replacement; the second was fit visually as a rigid body to an improved electron-density difference map. The structure was refined to R = 0.192 with two B values per residue (main chain and side chain) at 3.2 Å. The polar interactions of the peptides with the exosite of thrombin show differences consistent with the known flexibility in the interactions of the C-terminal peptide of hirudin with thrombin. The hirudin peptide in complex 2 has a higher temperature factor as compared with peptide 1 which may be correlated partly with a larger number of short-range electrostatic interactions between peptide 1 and thrombin and partly with the fact that thrombin 2 is -thrombin which is cleaved at Thr149A near the peptide binding site. Later, using this structure as a test case, it was shown that the position for the second thrombin could also be determined by a novel modification of the molecular-replacement method in which the contribution of the known molecule is subtracted from the structure factors. This approach is facile and applicable to any crystal containing two or more macromolecules in the asymmetric unit in which some but not all of the molecules can be determined by molecular replacement

Implementation-effectiveness trial of an ecological intervention for physical activity in ethnically diverse low income senior centers.

BackgroundAs the US population ages, there is an increasing need for evidence based, peer-led physical activity programs, particularly in ethnically diverse, low income senior centers where access is limited.Methods/designThe Peer Empowerment Program 4 Physical Activity' (PEP4PA) is a hybrid Type II implementation-effectiveness trial that is a peer-led physical activity (PA) intervention based on the ecological model of behavior change. The initial phase is a cluster randomized control trial randomized to either a peer-led PA intervention or usual center programming. After 18 months, the intervention sites are further randomized to continued support or no support for another 6 months. This study will be conducted at twelve senior centers in San Diego County in low income, diverse communities. In the intervention sites, 24 peer health coaches and 408 adults, aged 50 years and older, are invited to participate. Peer health coaches receive training and support and utilize a tablet computer for delivery and tracking. There are several levels of intervention. Individual components include pedometers, step goals, counseling, and feedback charts. Interpersonal components include group walks, group sharing and health tips, and monthly celebrations. Community components include review of PA resources, walkability audit, sustainability plan, and streetscape improvements. The primary outcome of interest is intensity and location of PA minutes per day, measured every 6 months by wrist and hip accelerometers and GPS devices. Secondary outcomes include blood pressure, physical, cognitive, and emotional functioning. Implementation measures include appropriateness & acceptability (perceived and actual fit), adoption & penetration (reach), fidelity (quantity & quality of intervention delivered), acceptability (satisfaction), costs, and sustainability.DiscussionUsing a peer led implementation strategy to deliver a multi-level community based PA program can enhance program adoption, implementation, and sustainment.Trial registrationClinicalTrials.gov, USA ( NCT02405325 ). Date of registration, March 20, 2015. This website also contains all items from the World Health Organization Trial Registration Data Set