483 research outputs found
Design and Expected Performance of the BTeV RICH
The BTeV experiment is a b-physics experiment designed to conduct precision
tests of the CKM description of CP violation and study rare processes involving
bottom and charm hadrons. The experiment will be located in the C0 interaction
region at the Fermilab Tevatron, and is intended to begin data-taking around
2007-2008. One of the most important elements of the BTeV spectrometer is the
ring-imaging Cerenkov detector (RICH) which is used for particle
identification. In this article we describe the BTeV RICH and present its
expected performance.Comment: 5 pages, 5 figures. Proceedings of the RICH2002 Conference, Pylos,
Greece, June 5-10, 200
Conceptualising climate â how public understanding of weather and climate influences perceptions of climate change globally
Although there is a growing body of literature exploring influences on public perceptions of climate change, little work has focused on how levels of conceptual understanding of deep time, namely the difference between weather and climate influence these perceptions. An online survey was distributed globally for the first time and used to measure respondentsâ levels of conceptual understanding of weather and climate and perceptions of the risks associated with climate change. Data was also gathered on respondent media trends to identify any key sources of information on climate change for respondents. 669 completed questionnaires were received with respondents being globally dispersed across 62 nations. Results were analysed to evaluate the relationship between the levels of conceptual understanding of weather and climate and concern with climate change amongst respondents. Analysis was also completed to assess how the media influences this relationship.
Results were presented for the Full Population (n=669) as well as regionally across European (n=303), North American (n=142), South American (n=20), African (n=57), Asian (n=99) and Oceania (n=44) response populations.
The results show little variation exists between levels of conceptual understanding of weather and climate and perceptions of climate change across all populations, despite a significant knowledge gap existing between perceived and actual levels of conceptual understanding of weather and climate. This challenges previous research which has demonstrated a link between levels of conceptual understanding and perceptions of the risks posed by climate change. The results did demonstrate a relationship exists between respondents demonstrating âVery Lowâ or âLowâ levels of conceptual understanding of weather and climate and relying on social media for the majority of information on climate change.
The results establish the salience of clear communication online to educate the public on the difference between weather and climate is key to improve levels of conceptual understanding. This research corroborates the findings of a large body of existing literature that global levels of concern with climate change are high. The results also show respondents who demonstrate high levels of scepticism around the risks posed by climate change do not consider the long term effects of climate change to be significant, despite demonstrating high levels of agreement with the scientific consensus on the anthropogenic causes of climate change. The effects of the concept of psychological distance on influencing perceptions of climate change risk were also observed. Respondents who identified changes to their local environment were found to significantly correlate with levels of concern with climate change though no relationship was identified between levels of conceptual understanding of weather and climate and this effect
Where Am I? Who Am I? Who Are You? Guided Disruption and Culturally Responsive Practice Through International Exchange
Our world and society is rapidly becoming more and more interdependent. A sustainable globalized society requires a population that is more culturally and linguistically sensitive, and requires educators with the dispositions and skills to 1) help students be more culturally responsive, and 2) work with an ever-increasing culturally and linguistically diverse population. Any core curriculum should include the infusion of a culturally responsive pedagogy. This presentation will examine how guided international exchange in teacher education programs may be a particularly powerful tool toward preparing teachers to infuse a culturally responsive pedagogy in their practice
The antisense oligonucleotide nusinersen for treatment of spinal muscular atrophy
Spinal muscular atrophy (SMA) is a rare, autosomal recessive neuromuscular degenerative disease characterized by loss of spinal cord motor neurons leading to progressive muscle wasting. The most common pathology results from a homozygous disruption in the survival motor neuron 1 (SMN1) gene on chromosome 5q13 via deletion, conversion, or mutation. SMN2 is a near duplicate of SMN1 that can produce full-length SMN mRNA transcripts, but its overall production capability of these mRNA transcripts is lower than that seen in SMN1. This leads to lower levels of functional SMN protein within motor neurons. The FDA approved nusinersen in December 2016 to treat SMA associated with SMN1 gene mutation. It is administered directly to the central nervous system by intrathecal injection. An antisense oligonucleotide (ASO) drug, nusinersen, provides an upcoming and promising treatment option for SMA and represents a novel pharmacological approach with a mechanism of action relevant for other neurodegenerative disorders. Nusinersen begins with four initial loading doses that are followed by three maintenance doses per year. Three major studies (CHERISH, ENDEAR, and NURTURE) have shown to improve motor function in early and late-onset individuals and reduce the chances of ventilator requirements in pre-symptomatic infants. Studies investigating the timing of drug delivery in mouse models of SMA report the best outcomes when drugs are delivered early before any significant motor function is lost. Nusinersen is a novel therapeutic approach with consistent results in all three studies and is proof of the novel concept for treating SMA and other neurodegenerative disorders in the future
The NANOGrav 15 yr Data Set: Constraints on Supermassive Black Hole Binaries from the Gravitational-wave Background
El conjunto de datos de 15 años de NANOGrav muestra evidencias de la presencia de un fondo de ondas gravitacionales (GWB) de baja frecuencia. Aunque muchos procesos fĂsicos pueden originar estas ondas gravitacionales de baja frecuencia, aquĂ analizamos la señal como procedente de una poblaciĂłn de agujeros negros binarios supermasivos (SMBH) distribuidos por todo el Universo. Demostramos que los modelos astrofĂsicos de poblaciones binarias SMBH son capaces de reproducir tanto la amplitud como la forma del espectro de ondas gravitacionales de baja frecuencia observado. Aunque mĂșltiples variaciones del modelo son capaces de reproducir el espectro GWB con nuestra precisiĂłn de medida actual, nuestros resultados subrayan la importancia de modelar con precisiĂłn la evoluciĂłn binaria para producir espectros GWB realistas. AdemĂĄs, aunque unos parĂĄmetros razonables son capaces de reproducir las observaciones de 15 años, la amplitud implĂcita del GWB requiere que un gran nĂșmero de parĂĄmetros se sitĂșen en los lĂmites de los valores esperados o que un pequeño nĂșmero de parĂĄmetros difieran notablemente de las expectativas estĂĄndar. Aunque todavĂa no somos capaces de establecer definitivamente el origen de la señal GWB inferida, la consistencia de la señal con las expectativas astrofĂsicas ofrece una perspectiva tentadora para confirmar que las binarias SMBH son capaces de formarse, alcanzar separaciones de sub-segundos y finalmente unirse. A medida que la importancia aumente con el tiempo, las caracterĂsticas de orden superior del espectro del GWB determinarĂĄn definitivamente la naturaleza del GWB y permitirĂĄn nuevas restricciones sobre las poblaciones de SMBH. © 2023The NANOGrav 15 yr data set shows evidence for the presence of a low-frequency gravitational-wave background (GWB). While many physical processes can source such low-frequency gravitational waves, here we analyze the signal as coming from a population of supermassive black hole (SMBH) binaries distributed throughout the Universe. We show that astrophysically motivated models of SMBH binary populations are able to reproduce both the amplitude and shape of the observed low-frequency gravitational-wave spectrum. While multiple model variations are able to reproduce the GWB spectrum at our current measurement precision, our results highlight the importance of accurately modeling binary evolution for producing realistic GWB spectra. Additionally, while reasonable parameters are able to reproduce the 15 yr observations, the implied GWB amplitude necessitates either a large number of parameters to be at the edges of expected values or a small number of parameters to be notably different from standard expectations. While we are not yet able to definitively establish the origin of the inferred GWB signal, the consistency of the signal with astrophysical expectations offers a tantalizing prospect for confirming that SMBH binaries are able to form, reach subparsec separations, and eventually coalesce. As the significance grows over time, higher-order features of the GWB spectrum will definitively determine the nature of the GWB and allow for novel constraints on SMBH populations. © 2023. The Author(s). Published by the American Astronomical Society
Assessment of existing information on Atlantic coastal fish habitats: development of a web-based spatial bibliography, query tools, and data summaries
The primary objective of this project, âthe Assessment of Existing Information on Atlantic Coastal Fish Habitatâ, is to inform conservation planning for the Atlantic Coastal Fish Habitat Partnership (ACFHP). ACFHP is recognized as a Partnership by the National Fish Habitat Action Plan (NFHAP), whose overall mission is to protect, restore, and enhance the nationâs fish and aquatic communities through partnerships that foster fish habitat conservation.
This project is a cooperative effort of NOAA/NOS Center for Coastal Monitoring and Assessment (CCMA) Biogeography Branch and ACFHP. The Assessment includes three components; 1. a representative bibliographic and assessment database, 2. a Geographical Information System (GIS) spatial framework, and 3. a summary document with description of methods, analyses of habitat assessment information, and recommendations for further work.
The spatial bibliography was created by linking the bibliographic table developed in Microsoft Excel and exported to SQL Server, with the spatial framework developed in ArcGIS and exported to GoogleMaps. The bibliography is a comprehensive, searchable database of over 500 selected documents and data sources on Atlantic coastal fish species and habitats. Key information captured for each entry includes basic bibliographic data, spatial footprint (e.g. waterbody or watershed), species and habitats covered, and electronic availability. Information on habitat condition indicators, threats, and conservation recommendations are extracted from each entry and recorded in a separate linked table.
The spatial framework is a functional digital map based on polygon layers of watersheds, estuarine and marine waterbodies derived from NOAAâs Coastal Assessment Framework, MMS/NOAAâs Multipurpose Marine Cadastre, and other sources, providing spatial reference for all of the documents cited in the bibliography.
Together, the bibliography and assessment tables and their spatial framework provide a powerful tool to query and assess available information through a publicly available web interface. They were designed to support the development of priorities for ACFHPâs conservation efforts within a geographic area extending from Maine to Florida, and from coastal watersheds seaward to the edge of the continental shelf. The Atlantic Coastal Fish Habitat Partnership has made initial use of the Assessment of Existing Information. Though it has not yet applied the AEI in a systematic or structured manner, it expects to find further uses as the draft conservation strategic plan is refined, and as regional action plans are developed. It also provides a means to move beyond an âassessment of existing informationâ towards an âassessment of fish habitatâ, and is being applied towards the National Fish Habitat Action Plan (NFHAP) 2010 Assessment. Beyond the scope of the current project, there may be application to broader initiatives such as Integrated Ecosystem Assessments (IEAs), Ecosystem Based Management (EBM), and Marine Spatial Planning (MSP)
Aberrant development corrected in adult-onset Huntington's disease iPSC-derived neuronal cultures via WNT signaling modulation
Aberrant neuronal development and the persistence of mitotic cellular populations have been implicated in a multitude of neurological disorders, including Huntington's disease (HD). However, the mechanism underlying this potential pathology remains unclear. We used a modified protocol to differentiate induced pluripotent stem cells (iPSCs) from HD patients and unaffected controls into neuronal cultures enriched for medium spiny neurons, the cell type most affected in HD. We performed single-cell and bulk transcriptomic and epigenomic analyses and demonstrated that a persistent cyclin D1+ neural stem cell (NSC) population is observed selectively in adult-onset HD iPSCs during differentiation. Treatment with a WNT inhibitor abrogates this NSC population while preserving neurons. Taken together, our findings identify a mechanism that may promote aberrant neurodevelopment and adult neurogenesis in adult-onset HD striatal neurons with the potential for therapeutic compensation
Multi-Messenger Gravitational Wave Searches with Pulsar Timing Arrays: Application to 3C66B Using the NANOGrav 11-year Data Set
When galaxies merge, the supermassive black holes in their centers may form
binaries and, during the process of merger, emit low-frequency gravitational
radiation in the process. In this paper we consider the galaxy 3C66B, which was
used as the target of the first multi-messenger search for gravitational waves.
Due to the observed periodicities present in the photometric and astrometric
data of the source of the source, it has been theorized to contain a
supermassive black hole binary. Its apparent 1.05-year orbital period would
place the gravitational wave emission directly in the pulsar timing band. Since
the first pulsar timing array study of 3C66B, revised models of the source have
been published, and timing array sensitivities and techniques have improved
dramatically. With these advances, we further constrain the chirp mass of the
potential supermassive black hole binary in 3C66B to less than using data from the NANOGrav 11-year data set. This
upper limit provides a factor of 1.6 improvement over previous limits, and a
factor of 4.3 over the first search done. Nevertheless, the most recent orbital
model for the source is still consistent with our limit from pulsar timing
array data. In addition, we are able to quantify the improvement made by the
inclusion of source properties gleaned from electromagnetic data to `blind'
pulsar timing array searches. With these methods, it is apparent that it is not
necessary to obtain exact a priori knowledge of the period of a binary to gain
meaningful astrophysical inferences.Comment: 14 pages, 6 figures. Accepted by Ap
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