65 research outputs found
Racial / Ethnic and Gender Diversity in the Orchestra Field
For all cultural institutions, knowledge and information are becoming critical tools in the work of navigating a course through this new landscape. In particular, there is a recognized value in learning from the past in order to inform action for the future. By offering a new baseline, Racial / Ethnic and Gender Diversity in the Orchestra Field provides a clear and comprehensive picture of the demographic composition of orchestras: musicians, conductors, board members, and staff. Of course, each orchestra has its own unique story to tell. Nonetheless, the field-wide data in this report provides an essential foundation for analysis, understanding, debate, and action.Our report looks back over nearly four decades of orchestra demographics data to present an analysis intended to promote learning and action among orchestra stakeholders, inform public dialogue, and serve as a stimulus for further research. In this report, we present an analysis of the following data sets:Musicians: Race and Ethnicity (1980-2014); Gender (1978-2014)Conductors: Race and Ethnicity (2006-2016); Gender (2006-2016)Staff: Race and Ethnicity (2010-2014); Gender (2010-2014)Board Members: Race andEthnicity (2010-2014); Gender (2010-2014)Our analysis is shaped by available data, and the terms that we use to categorize people by race, ethnicity, and gender reflect those employed within our data sources
Refining biological monitoring of hydromorphological change in river channels using benthic riverfly larvae (Ephemeroptera, Plecoptera and Trichoptera).
Rivers and their catchments are under mounting pressure from direct channel modification, intensification of land use, and from a legacy of decades of channelisation. Recent legislation, in the form of the EU Water Framework Directive, places a greater emphasis on the management of water bodies as holistic systems, and includes the explicit consideration of hydromorphological quality, which describes the hydrologic and geomorphic elements of river habitats. These are defined specifically as hydrological regime, river continuity and river morphology. This appreciates that sediment and flow regimes, along with the channel structure, provides the 'template' on which stream ecological structure and function is built.
Invertebrate fauna contribute significantly to the biodiversity of rivers, and often form the basis of monitoring river health. However much of the fundamental ecological knowledge base on the response of invertebrates to hydromorphological change needed to make informed decisions and accurate predictions, is either lacking, inadequate or contradictory. This thesis addresses some of the key potential shortcomings in recent bio-assessment that others have alluded to, but which have rarely been explored in the context of direct channel manipulations. By using two case studies of, realignment in a natural upland catchment, and flood protection engineering in an urban stream, this study investigates the sensitivity of hydromorphological impact assessment methods that rely on biodiversity patterns of benthic riverfly (Ephemeroptera, Plecoptera and Trichoptera) larva.
This work employed widely used biomonitoring indices of benthic riverfly larva abundance, species richness, alpha and beta diversity, and community composition, applied over a range of spatial scales, in combination with spatially contemporaneous physical habitat data, to describe and explain community changes in response to disturbance, and patterns of natural variation. The effects of restoration were investigated using a high degree of sample replication within channels and across the wider catchment, as well as contrasting spring and autumn seasons. To assess change in a small urban channel, approaches that explicitly consider spatial elements of community data, using spatial eigenvectors analysis, were applied to spatially detrend community data and directly investigate spatial patterns.
Restoration of the Rottal Burn was found to be successful in restoring habitat diversity and geomorphic processes, and in turn increasing reach scale species richness and beta diversity through the gradual arrival of rare and specialist taxa into novel habitats. Catchment scale replication revealed high variation in diversity indices of modified and undisturbed streams, and a strong temporal pattern related to antecedent flow conditions. Channels with greater habitat heterogeneity were able to maintain high gamma diversity during times of high flow stress by providing a number of low flow refuges along their length.
The urban Brox Burn had surprisingly high riverfly richness and diversity driven by small scale hydraulic heterogeneity, created by bed roughness resulting in a range of microhabitats. Riverfly community responses to direct channel dredging could not be detected by measurements of average richness and diversity, however distinct changes were seen in gamma diversity, the identity of community members and their arrangement among sample patches. Impacts of sediment pollution release due to engineering were short lived and apparently had little detrimental impact on biodiversity. Strong spatial patterns of community assembly on the stream bed were uncovered, relating to longitudinal, edge and patchy patterns. Significant habitat drivers of community composition were confounded by high amounts of spatial autocorrelation, especially hydraulic variables.
Due to the strongly physical and spatial nature of hydromorphological disturbance, turnover of species between sample locations at a range of scales, and the spatial arrangement of habitats and communities is of more use for detecting these types of subtle changes compared to mean richness or diversity. These findings have implications for the targeting of resources for monitoring of restoration, or engineering disturbances, in order to be sensitive to hydromorphological change. Efforts should target the main area of natural variability within the system, either replicating sampling in time or space to distinguish effects of impact. Spatial patterns, measures of beta diversity and species identity can be better exploited to identify systems with functioning geomorphological processes. Channel typologies proved misleading, and quantification of habitat and selection of control sites using multiple pre-defined criteria should be carried out. Studies of restoration operations and engineering impacts provide considerable opportunities for advancing our knowledge of the mechanisms that drive community response under a range of conditions to improve impact detectio
Bayesian Inference of Initial Conditions from Non-Linear Cosmic Structures using Field-Level Emulators
Analysing next-generation cosmological data requires balancing accurate
modeling of non-linear gravitational structure formation and computational
demands. We propose a solution by introducing a machine learning-based
field-level emulator, within the Hamiltonian Monte Carlo-based Bayesian Origin
Reconstruction from Galaxies (BORG) inference algorithm. Built on a V-net
neural network architecture, the emulator enhances the predictions by
first-order Lagrangian perturbation theory to be accurately aligned with full
-body simulations while significantly reducing evaluation time. We test its
incorporation in BORG for sampling cosmic initial conditions using mock data
based on non-linear large-scale structures from -body simulations and
Gaussian noise. The method efficiently and accurately explores the
high-dimensional parameter space of initial conditions, fully extracting the
cross-correlation information of the data field binned at a resolution of
Mpc. Percent-level agreement with the ground truth in the power
spectrum and bispectrum is achieved up to the Nyquist frequency . Posterior resimulations - using the
inferred initial conditions for -body simulations - show that the recovery
of information in the initial conditions is sufficient to accurately reproduce
halo properties. In particular, we show highly accurate
halo mass function and stacked density profiles of haloes in different mass
bins . As all available
cross-correlation information is extracted, we acknowledge that limitations in
recovering the initial conditions stem from the noise level and data grid
resolution. This is promising as it underscores the significance of accurate
non-linear modeling, indicating the potential for extracting additional
information at smaller scales.Comment: 16 pages, 11 figure
Response of terrestrial net primary productivity (NPPT) in the Wujiang catchment (China) to the construction of cascade hydropower stations
The damming of rivers results in hydrological modifications that not only affect the aquatic ecosystem but also adjoining terrestrial systems. Thirteen dams commissioned along the Wujiang River have induced ecological problems, including decreased water turbidity and loss of biodiversity, which potentially influence ecosystem net primary production (NPP) and hence the sequestration, transformation, and storage of carbon. We used terrestrial NPP (NPPT) as a bioindicator to assess the impact of dams on carbon storage in the Wujiang catchment. MODIS satellite and meteorological data were used as inputs to the CASA model to calculate annual NPPT from 2000 to 2014. NPPT was calculated at the catchment and landscape scale to quantify the impact of dams on surrounding terrestrial ecosystems. Mean NPPT was calculated for concentric buffer zones covering a range of spatial extents (0â10 km) from the reservoir shoreline. We found a negligible impact from construction of a single dam on NPPT at the catchment scale. By contrast, the impact of dam construction was scale-dependent, with a stronger landscape-scale effect observed at short distances (i.e., 0â1 km) from the reservoir. Decreases in NPPT were mainly ascribed to the loss of vegetated land resulting from dam impoundment and subsequent urbanization of the surrounding area
Changing foreign policy: the Obama Administrationâs decision to oust Mubarak
This paper analyses the decision of the Obama administration to redirect its
foreign policy towards Egypt in the wake of the Arab Spring. It attempts to
highlight the issue of how governments deal with decision-making at times of
crisis, and under which circumstances they take critical decisions that lead to
major shifts in their foreign policy track record. It focuses on the process that
led to a reassessment of US (United States) foreign policy, shifting from decades
of support to the autocratic regime of Hosni Mubarak, towards backing his
ouster. Specifically, the paper attempts to assess to what extent the decision to
withdraw US support from a longstanding state-leader and ally in the Middle
East can be seen as a foreign policy change (FPC). A relevant research question
this paper pursues is: how can the withdrawal of US support to a regime
considered as an ally be considered, in itself, as a radical FPC
The study of fretting fatigue using finite element analysis and electron microscopy
SIGLEAvailable from British Library Document Supply Centre- DSC:D40398/82 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
AnvÀndning av maskininlÀrning för att förstÄ kosmisk expansion
This thesis aims at using novel machine learning techniques to test the dynamics of the Universe via the cosmological redshift-distance test. Currently, one of the most outstanding questions in cosmology is the physical cause of the accelerating cosmic expansion observed with supernovae. Simultaneously, tensions in measurements of the Hubble expansion parameter are emerging. Measuring the Universe expansion with next generation galaxy imaging surveys, such as provided by the Vera Rubin Observatory, offers the opportunity to discover new physics governing the Universe dynamics. In this thesis, with the long-term goal to unravel these peculiarities, we create a deep generative model in the form of a convolutional variational auto-encoder (VAE), trained with a "Variational Mixture of Posteriors" prior (VampPrior) and high-resolution galaxy images from the simulation project \texttt{TNG-50}. Our model is able to learn a prior on the visual features of galaxies and can generate synthetic galaxy images which preserve the coarse features (shape, size, inclination, and surface brightness profile), but not finer morphological features, such as spiral arms. The generative model for galaxy images is applicable to uses outside the scope of this thesis and is thus a contribution in itself. We next implement a cosmological pinhole camera model, taking angular diameter changes with redshift into account, to forward simulate the actual observation on a telescope detector. Building upon the hypothesis that certain features of galaxies should be of proper physical sizes, we use probabilistic triangulation to find the comoving distance to these in a flat () Universe. Using a sample of high-resolution galaxy images from redshifts from \texttt{TNG-50}, we demonstrate that the implemented Bayesian inference approach successfully estimates within -error ( Mpc for ). Including the surface brightness attenuation and utilizing the avalanche of upcoming galaxy images could significantly lower the uncertainties. This thesis thus shows a promising path forward utilizing novel machine learning techniques and massive next-generation imaging data to improve and generalize the traditional cosmological angular-diameter test, which in turn has the potential to increase our understanding of the Universe.Denna avhandling syftar till att anvÀnda nya maskininlÀrningstekniker för att testa universums dynamik via det kosmologiska rödförskjutningsavstÄndstestet. För nÀrvarande Àr en av de mest framstÄende frÄgorna inom kosmologi den fysiska orsaken till den accelererande kosmiska expansionen som observerats med supernovor. Samtidigt uppstÄr spÀnningar i mÀtningar av Hubble-expansionsparametern . Att mÀta universums expansion med nÀsta generations galaxundersökningar, sÄsom de som ska genomföras av Vera Rubin Observatory, ger möjlighet att upptÀcka ny fysik som styr universums dynamik. I den andan skapar vi i den hÀr avhandlingen en djup generativ modell i form av en "convolutional variational auto-encoder" (VAE), trÀnad med en "Variational Mixture of Posteriors" prior (VampPrior) och högupplösta galaxbilder frÄn simuleringsprojektet \texttt{TNG-50}. VÄr modell kan lÀra sig en "prior" om galaxernas visuella egenskaper och kan generera syntetiska galaxbilder som bevarar de grova dragen (form, storlek, lutning och ytans ljusprofil), men inte finare morfologiska egenskaper, sÄsom spiralarmar. Den generativa modellen för galaxbilder Àr tillÀmplig pÄ anvÀndningar som inte omfattas av denna avhandling och Àr dÀrmed ett bidrag i sig. DÀrefter implementerar vi en kosmologisk hÄlkameramodell, med vilken hÀnsyn till förÀndringar i vinkelstorleken med rödförskjutning tas, för att framÄt-simulera den faktiska observationen pÄ en teleskopdetektor. Med utgÄngspunkt frÄn hypotesen att galaxer i grunden borde ha gemensamma egenskaper med liknande fysiska storlekar, anvÀnder vi probabilistisk triangulering för att hitta avstÄndet (s.k. "comoving distance") till dessa i ett platt () universum. Med hjÀlp av ett urval av högupplösta galaxbilder frÄn rödförskjutningar frÄn \texttt {TNG-50} visar vi att den implementerade "Bayesian inference"-metoden framgÄngsrikt uppskattar inom felmarginaler ( Mpc för ). Att inkludera dÀmpning i ytljusstyrka med rödförskjutning och att anvÀnda den massiva mÀngd av kommande galaxbilder skulle kunna minska den erhÄllna osÀkerheten betydligt. Denna avhandling visar sÄledes en lovande vÀg framÄt med nya maskininlÀrningstekniker och kommande enorma mÀngder av galaxbilder för att förbÀttra och generalisera det traditionella kosmologiska vinkeldiametertestet, vilket i sin tur har potentialen att öka vÄr förstÄelse om universum
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