Harnessing demographic differences in organizations GUILLAUME, YVES R.F.; DAWSON, JEREMY F.; OTAYE-EBEDE, LILIAN ...
Journal of organizational behavior,
February 2017, Letnik:
38, Številka:
2
Journal Article
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To account for the double-edged nature of demographic workplace diversity (i.e,. relational demography, work group diversity, and organizational diversity) effects on social integration, performance, ...and well-being-related variables, research has moved away from simple main effect approaches and started examining variables that moderate these effects. While there is no shortage of primary studies of the conditions under which diversity leads to positive or negative outcomes, it remains unclear which contingency factors make it work. Using the Categorization-Elaboration Model as our theoretical lens, we review variables moderating the effects of workplace diversity on social integration, performance, and well-being outcomes, focusing on factors that organizations and managers have control over (i.e., strategy, unit design, human resource, leadership, climate/culture, and individual differences). We point out avenues for future research and conclude with practical implications.
La Crosse virus (LACV), a zoonotic Bunyavirus, is a major cause of pediatric viral encephalitis in the United States. A hallmark of neurological diseases caused by LACV and other encephalitic viruses ...is the induction of neuronal cell death. Innate immune responses have been implicated in neuronal damage, but no mechanism has been elucidated. By using in vitro studies in primary neurons and in vivo studies in mice, we have shown that LACV infection induced the RNA helicase, RIG-I, and mitochondrial antiviral signaling protein (MAVS) signaling pathway, resulting in upregulation of the sterile alpha and TIR-containing motif 1 (SARM1), an adaptor molecule that we found to be directly involved in neuronal damage. SARM1-mediated cell death was associated with induced oxidative stress response and mitochondrial damage. These studies provide an innate-immune signaling mechanism for virus-induced neuronal death and reveal potential targets for development of therapeutics to treat encephalitic viral infections.
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► Bunyavirus infection induces SARM1 upregulation in neurons ► SARM1 mediates bunyavirus-induced cell death via oxidative stress response ► SARM1 upregulation following virus infection in neurons is MAVS dependent ► SARM1 localizes with MAVS at the mitochondria and induces apoptosis
The choice of hydrological model structure, that is, a model's selection of states and fluxes and the equations used to describe them, strongly controls model performance and realism. This work ...investigates differences in performance of 36 lumped conceptual model structures calibrated to and evaluated on daily streamflow data in 559 catchments across the United States. Model performance is compared against a benchmark that accounts for the seasonality of flows in each catchment. We find that our model ensemble struggles to beat the benchmark in snow‐dominated catchments. In most other catchments model structure equifinality (i.e., cases where different models achieve similar high efficiency scores) can be very high. We find no relation between the number of model parameters and performance during either calibration or evaluation periods nor evidence of increased risk of overfitting for models with more parameters. Instead, the choice of model parametrization (i.e., which equations are used and how parameters are used within them) dictates the model's strengths and weaknesses. Results suggest that certain model structures are inherently better suited for certain objective functions and thus for certain study purposes. We find no clear relationships between the catchments where any model performs well and descriptors of those catchments' geology, topography, soil, and vegetation characteristics. Instead, model suitability seems to relate strongest to the streamflow regime each catchment generates, and we have formulated several tentative hypotheses that relate commonalities in model structure to similarities in model performance. Modeling results are made publicly available for further investigation.
Key Points
Conceptual model structure uncertainty is high across different catchments and objective functions
There is no evidence of systematic overfitting for models with up to 15 calibrated parameters
Model performance relates more to streamflow signatures than to climate or catchment descriptors
Exercise initiates a cascade of inflammatory events, which ultimately lead to long-term effects on human health. During and after acute exercise in skeletal muscle, interactions between immune cells, ...cytokines, and other intracellular components, create an inflammatory milieu responsible for the recovery and adaption from an exercise bout. In the systemic circulation, cytokines released from muscle (myokines) mediate metabolic and inflammatory processes. Moderate exercise training results in improvements in systemic inflammation, evident by reductions in acute phase proteins. The anti-inflammatory effects of regular exercise include actions dependent and independent of changes in adipose tissue mass. Future research should encompass approaches, which attempt to integrate other, less-recognized physiological processes with acute and long-term inflammatory changes. This will include investigation into metabolic, endocrine, and immune components of various tissues and organs.
Aging results in chronic systemic inflammation that can alter neuroinflammation of the brain. Specifically, microglia shift to a pro-inflammatory phenotype predisposing them to hyperactivation upon ...stimulation by peripheral immune signals. It is proposed that certain nutrients can delay brain aging by preventing or reversing microglial hyperactivation. Butyrate, a short-chain fatty acid (SCFA) produced primarily by bacterial fermentation of fiber in the colon, has been extensively studied pharmacologically as a histone deacetylase inhibitor and serves as an attractive therapeutic candidate, as butyrate has also been shown to be anti-inflammatory and improve memory in animal models. In this study, we demonstrate that butyrate can attenuate pro-inflammatory cytokine expression in microglia in aged mice. It is still not fully understood, however, if an increase in butyrate-producing bacteria in the gut as a consequence of a diet high in soluble fiber could affect microglial activation during aging. Adult and aged mice were fed either a 1% cellulose (low fiber) or 5% inulin (high fiber) diet for 4 weeks. Findings indicate that mice fed inulin had an altered gut microbiome and increased butyrate, acetate, and total SCFA production. In addition, histological scoring of the distal colon demonstrated that aged animals on the low fiber diet had increased inflammatory infiltrate that was significantly reduced in animals consuming the high fiber diet. Furthermore, gene expression of inflammatory markers, epigenetic regulators, and the microglial sensory apparatus (i.e., the sensome) were altered by both diet and age, with aged animals exhibiting a more anti-inflammatory microglial profile on the high fiber diet. Taken together, high fiber supplementation in aging is a non-invasive strategy to increase butyrate levels, and these data suggest that an increase in butyrate through added soluble fiber such as inulin could counterbalance the age-related microbiota dysbiosis, potentially leading to neurological benefits.
Precipitation (P) and potential evaporation (Ep) are commonly studied drivers of changing freshwater availability, as aridity (Ep/P) explains ∼90% of the spatial differences in mean runoff across the ...globe. However, it is unclear if changes in aridity over time are also the most important cause for temporal changes in mean runoff and how this degree of importance varies regionally. We show that previous global assessments that address these questions do not properly account for changes due to precipitation, and thereby strongly underestimate the effects of precipitation on runoff. To resolve this shortcoming, we provide an improved Budyko‐based global assessment of the relative and absolute sensitivity of precipitation, potential evaporation, and other factors to changes in mean‐annual runoff. The absolute elasticity of runoff to potential evaporation changes is always lower than the elasticity to precipitation changes. The global pattern indicates that for 83% of the land grid cells runoff is most sensitive to precipitation changes, while other factors dominate for the remaining 17%. This dominant role of precipitation contradicts previous global assessments, which considered the impacts of aridity changes as a ratio. We highlight that dryland regions generally display high absolute sensitivities of runoff to changes in precipitation, however within dryland regions the relative sensitivity of runoff to changes in other factors (e.g., changing climatic variability, CO2‐vegetation feedbacks, and anthropogenic modifications to the landscape) is often far higher. Nonetheless, at the global scale, surface water resources are most sensitive to temporal changes in precipitation.
Key Points
Budyko‐based global assessment for the sensitivity of runoff to changes in precipitation, potential evaporation, and other factors
At a global scale, surface water resources are most sensitive to changes in precipitation, but regional exceptions exist
In dry lands, sensitivities of runoff to precipitation and potential evaporation changes are lower than the sensitivity to all other factors
This paper presents the Modular Assessment of Rainfall–Runoff Models Toolbox (MARRMoT): a modular open-source toolbox containing documentation and model code based on 46 existing conceptual ...hydrologic models. The toolbox is developed in MATLAB and works with Octave. MARRMoT models are based solely on traceable published material and model documentation, not on already-existing computer code. Models are implemented following several good practices of model development: the definition of model equations (the mathematical model) is kept separate from the numerical methods used to solve these equations (the numerical model) to generate clean code that is easy to adjust and debug; the implicit Euler time-stepping scheme is provided as the default option to numerically approximate each model's ordinary differential equations in a more robust way than (common) explicit schemes would; threshold equations are smoothed to avoid discontinuities in the model's objective function space; and the model equations are solved simultaneously, avoiding the physically unrealistic sequential solving of fluxes. Generalized parameter ranges are provided to assist with model inter-comparison studies. In addition to this paper and its Supplement, a user manual is provided together with several workflow scripts that show basic example applications of the toolbox. The toolbox and user manual are available from https://github.com/wknoben/MARRMoT (last access: 30 May 2019; https://doi.org/10.5281/zenodo.3235664). Our main scientific objective in developing this toolbox is to facilitate the inter-comparison of conceptual hydrological model structures which are in widespread use in order to ultimately reduce the uncertainty in model structure selection.
We present the results from a series of experiments investigating the dynamics of gravity currents which form when a dense saline or particle-laden plume issuing from a moving source interacts with a ...horizontal surface. We define the dimensionless parameter $P$ as the ratio of the source speed, $u_a$, to the buoyancy speed, $(B_0/z_0)^{1/3}$, where $B_0$ and $z_0$ are the source buoyancy flux and height above the horizontal surface, respectively. Using our experimental data, we determine that the limiting case in which $P=P_c$ the gravity current only spreads downstream of the initial impact point occurs when $P_c=0.83\pm 0.02$. For $P< P_c$, from our experiments we observe that the plume forms a gravity current that spreads out in all directions from the point of impact and the propagation of the gravity current is analogous to a classical constant-flux gravity current. For $P>P_c$, we observe that the descending plume is bent over and develops a pair of counter-rotating line vortices along the axis of the plume. The ensuing gravity current spreads out downstream of the source, normal to the motion of the source. Analogous processes occur with particle-laden plumes, but there is a second dimensionless parameter $S$, the ratio of the particle fall speed, $v_s$, to the vertical speed of a plume in a crossflow, $(B_0/u_a z_0)^{1/2}$. For $S\ll 1$, particles remain well mixed in the plume and a particle-driven gravity current develops. For $S\gg 1$, particles separate from the plume prior to impacting the boundary which leads to a fall deposit and no gravity current. We discuss these results in the context of deep-sea mining.
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