Negro Soy Yo

In Negro Soy Yo Marc D. Perry explores Cuba’s hip hop movement as a window into the racial complexities of the island’s ongoing transition from revolutionary socialism toward free-market capitalism. Centering on the music and lives of black-identified raperos (rappers), Perry examines the ways these young artists craft notions of black Cuban identity and racial citizenship, along with calls for racial justice, at the fraught confluence of growing Afro-Cuban marginalization and long held perceptions of Cuba as a non-racial nation. Situating hip hop within a long history of Cuban racial politics, Perry discusses the artistic and cultural exchanges between raperos and North American rappers and activists, and their relationships with older Afro-Cuban intellectuals and African American political exiles. He also examines critiques of Cuban patriarchy by female raperos, the competing rise of reggaetón, as well as state efforts to incorporate hip hop into its cultural institutions. At this pivotal moment of Cuban-U.S. relations, Perry's analysis illuminates the evolving dynamics of race, agency, and neoliberal transformation amid a Cuba in historic flux. This title was made Open Access by libraries from around the world through Knowledge Unlatched

Negro Soy Yo

In Negro Soy Yo Marc D. Perry explores Cuba’s hip hop movement as a window into the racial complexities of the island’s ongoing transition from revolutionary socialism toward free-market capitalism. Centering on the music and lives of black-identified raperos (rappers), Perry examines the ways these young artists craft notions of black Cuban identity and racial citizenship, along with calls for racial justice, at the fraught confluence of growing Afro-Cuban marginalization and long held perceptions of Cuba as a non-racial nation. Situating hip hop within a long history of Cuban racial politics, Perry discusses the artistic and cultural exchanges between raperos and North American rappers and activists, and their relationships with older Afro-Cuban intellectuals and African American political exiles. He also examines critiques of Cuban patriarchy by female raperos, the competing rise of reggaetón, as well as state efforts to incorporate hip hop into its cultural institutions. At this pivotal moment of Cuban-U.S. relations, Perry's analysis illuminates the evolving dynamics of race, agency, and neoliberal transformation amid a Cuba in historic flux. This title was made Open Access by libraries from around the world through Knowledge Unlatched

Sex Determination by Morphological Measurements of Young Rockhopper Penguins (\u3cem\u3eEudyptes chrysocome\u3c/em\u3e) During the Crèche Phase

To provide an easy and reliable work tool to identify the sex of Rockhopper Penguin (Eudyptes chrysocome) chicks, we weighed and measured 95 nestlings in the crèche phase during 24-31 January 2017 on the Falkland Islands, Argentina. Sex was subsequently determined using DNA analyses of blood from the same individuals. Significant differences were found in bill length (exposed culmen), bill depth and width, flipper length, and diagonal tarsus, but stepwise discriminant analysis showed bill length to be the best predictor for sex determination. Our model correctly classified 82.7% of males and 90.2% of females (overall correct classification 86.2%). Threshold bill length was 36.64 mm, with values above this point being males and values below being females. Therefore, it appears that measuring bill length is an easy, immediate, and accurate method to sex Rockhopper Penguins during the crèche phase

HRP Commanding Lessons Learned: Commanding to HRF Racks

No abstract availabl

Discrete mode laser diodes with ultra narrow linewidth emission <3kHz

Ex-facet, free-running ultra-low linewidth (<3 kHz), single mode laser emission is demonstrated using low cost, regrowth-free ridge waveguide discrete mode Fabry-Perot laser diode chips

Microglia modulate hippocampal neural precursor activity in response to exercise and aging

Exercise has been shown to positively augment adult hippocampal neurogenesis; however, the cellular and molecular pathways mediating this effect remain largely unknown. Previous studies have suggested that microglia may have the ability to differentially instruct neurogenesis in the adult brain. Here, we used transgenic Csf1r-GFP mice to investigate whether hippocampal microglia directly influence the activation of neural precursor cells. Our results revealed that an exercise-induced increase in neural precursor cell activity was mediated via endogenous microglia and abolished when these cells were selectively removed from hippocampal cultures. Conversely, microglia from the hippocampi of animals that had exercised were able to activate latent neural precursor cells when added to neurosphere preparations from sedentary mice. We also investigated the role of CX(3)CL1, a chemokine that is known to provide a more neuroprotective microglial phenotype. Intraparenchymal infusion of a blocking antibody against the CX(3)CL1 receptor, CX(3)CR1, but not control IgG, dramatically reduced the neurosphere formation frequency in mice that had exercised. While an increase in soluble CX(3)CL1 was observed following running, reduced levels of this chemokine were found in the aged brain. Lower levels of CX(3)CL1 with advancing age correlated with the natural decline in neural precursor cell activity, a state that could be partially alleviated through removal of microglia. These findings provide the first direct evidence that endogenous microglia can exert a dual and opposing influence on neural precursor cell activity within the hippocampus, and that signaling through the CX(3)CL1-CX(3)CR1 axis critically contributes toward this process

Insights into Rock-Ice Avalanche Dynamics by Combined Analysis of Seismic Recordings and a Numerical Avalanche Mode

Rock‐ice avalanches larger than 1 × 106 m3 are high‐magnitude, low‐frequency events that may occur in all ice‐covered, high mountain areas around the world and can cause extensive damage if they reach populated regions. The temporal and spatial evolution of the seismic signature from two events was analyzed, and recordings at selected stations were compared to numerical model results of avalanche propagation. The first event is a rock‐ice avalanche from Iliamna volcano in Alaska which serves as a “natural laboratory” with simple geometric conditions. The second one originated on Aoraki/Mt. Cook, New Zealand Southern Alps, and is characterized by a much more complex topography. A dynamic numerical model was used to calculate total avalanche momentum, total kinetic energy, and total frictional work rate, among other parameters. These three parameters correlate with characteristics of the seismic signature such as duration and signal envelopes, while other parameters such as flow depths, flow path and deposition geometry are well in agreement with observations. The total frictional work rate shows the best correlation with the absolute seismic amplitude, suggesting that it may be used as an independent model evaluation criterion and in certain cases as model calibration parameter. The good fit is likely because the total frictional work rate represents the avalanche ’s energy loss rate, part of which is captured by the seismometer. Deviations between corresponding calculated and measured parameters result from site and path effects which affect the recorded seismic signal or indicate deficiencies of the numerical model. The seismic recordings contain additional information about when an avalanche reaches changes in topography along the runout path and enable more accurate velocity calculations. The new concept of direct comparison of seismic and avalanche modeling data helps to constrain the numerical model input parameters and to improve the understanding of (rock‐ice) avalanche dynamics

Multi-component avalanches for rock- and ice-falls to potential debris flow transition modelling

Rock/ice avalanches are complex gravitational flows involving three important physicalprocesses: entrainment, phase-changes, and flow transitions. The basic complexity of modelling rock/ice avalanches lies in the fact that the flow is a mixture of rock, ice, water, snow, soil sediments. The interaction of these components can lead to flow transitions which is difficult to model with simplified flow rheologies. For example, a flow initially composed of rocks and ice can transition into a long-runout debris flow, dependent on the entrainment of water, water-saturated sediments and/or snow. The dynamic behaviour of rock/ice avalanches is therefore highly difficult to predict because the flow mixture is dependent on the hydrological and geomorphological properties along the avalanche track. These properties can vary from year to year but even from season to season. The problem is intensified by the fact that frictional shearing can produce enough heat energy to melt ice and snow, leading to additional water in the flow. In this contribution, we present a new RAMMS module specifically designed to simulate single- and multicomponent avalanches of rock, ice, water, snow, and ice. The rheology of the flow is treated by using the concept of component activation energy. The model includes both snow and sediment/water/ice entrainment modules. A unique feature of the model is that it tracks the temperature of the rock, ice and water phases and therefore can treat phase changes. We apply the model on the Chamoli case-study to highlight the potential and present limitations of the model.

A Proof of Uniqueness of the Taub-bolt Instanton

We show that the Riemannian Schwarzschild and the ``Taub-bolt'' instanton solutions are the only spaces (M,g) such that 1) M is a 4-dimensional, simply connected manifold with a Riemannian, Ricci-flat C^2-metric g which admits (at least) a 1-parameter group of isometries H without isolated fixed points on M. 2) The quotient (M L)/H (where L is the set of fixed points of H) is an asymptotically flat manifold, and the length of the Killing field corresponding to H tends to a constant at infinity.Comment: 20 pages. LaTeX. Substantially extended and correcte