504 research outputs found
Simultaneous spectra and radio properties of BL Lac's
We present the results of nine years of the blazar observing programme at the
RATAN-600 radio telescope (2005-2014). The data were obtained at six frequency
bands (1.1, 2.3, 4.8, 7.7, 11.2, 21.7 GHz) for 290 blazars, mostly BL Lacs. In
addition, we used data at 37 GHz obtained quasi-simultaneously with the
Metsahovi radio observatory for some sources. The sample includes blazars of
three types: high-synchrotron peaked (HSP), low-synchrotron peaked (LSP), and
intermediate-synchrotron peaked (ISP). We present several epochs of flux
density measurements, simultaneous radio spectra, spectral indices and
properties of their variability. The analysis of the radio properties of
different classes of blazars showed that LSP and HSP BL Lac blazars are quite
different objects on average. LSPs have higher flux densities, flatter spectra
and their variability increases as higher frequencies are considered. On the
other hand, HSPs are very faint in radio domain, tend to have steep low
frequency spectra, and they are less variable than LSPs at all frequencies.
Another result is spectral flattening above 7.7 GHz detected in HSPs, while an
average LSP spectrum typically remains flat at both the low and high frequency
ranges we considered.Comment: 14 pages, 6 figures. Accepted for publication in Astronomische
Nachrichte
The dynamic metabolism of hyaluronan regulates the cytosolic concentration of UDP-GlcNAc
Hyaluronan, a macromolecular glycosaminoglycan, is normally synthesized by hyaluronan synthases at the plasma membrane using cytosolic UDP-GlcUA and UDP-GlcNAc substrates and extruding the elongating chain into the extracellular space. The cellular metabolism (synthesis and catabolism) of hyaluronan is dynamic. UDP-GlcNAc is also the substrate for O-GlcNAc transferase, which is central to the control of many cytosolic pathways. This Perspective outlines recent data for regulation of hyaluronan synthesis and catabolism that support a model that hyaluronan metabolism can be a rheostat for controlling an acceptable normal range of cytosolic UDP-GlcNAc concentrations in order to maintain normal cell functions
Perspectives and Practices: Archival Processing Metrics Survey Findings
Professional literature and case studies demonstrate that processing metrics are valuable in advocating for resources, informing priorities, supporting grant proposals, and predicting costs for collection storage and care. This article analyzes responses to an archival processing metrics survey that gathered perspectives and practices from archivists working in a variety of repository types. The findings describe how archivists collect processing metrics in different ways, what data points they view as essential, and how they use certain data points to serve specific purposes. The findings indicate that although most respondents acknowledge the value of processing metrics, the majority of them still do not employ metrics in daily operations. The findings note barriers to processing assessment and highlight disparities in resources, personnel, and practices across the profession. The findings reveal a lack of clarity about best practices for archival processing assessment and a need for profession-wide guidelines. The article suggests resources for those wishing to implement processing metrics
Novice Teachers Navigating Mentoring Relationships in the United States
Devido Ă escassez nacional de professores nos Estados Unidos, a manutenção desses profissionais no sistema Ă© hoje mais crĂtica do que nunca. Nesta linha, este estudo visa compreender que experiĂŞncias de tutoria e apoio Ă indução podem auxiliar neste objetivo. Enquadrada pela teoria do dialogismo de Bakhtin, a natureza longitudinal e qualitativa deste estudo explora as experiĂŞncias de professores iniciantes (PI) em escolas dos primeiros anos de escolarização nos Estados Unidos, cujo desempenho profissional inicial ocorreu num cenário de pandemia global. Mais especificamente, concentramo-nos no apoio formal e informal que receberam nesses primeiros anos de exercĂcio. A análise dos dados, que incluiu entrevistas aprofundadas com os PI, revelou dois temas principais: 1) despriorização da tutoria e 2) inconsistĂŞncias na tutoria. As implicações deste estudo ampliam a literatura existente, oferecendo evidĂŞncias baseadas em ações para melhorar a orientação e a indução. O foco na manutenção de PI no sistema atravĂ©s de suporte e orientação beneficia está área no presente e no futuro.Amid the national teaching shortage in the United States, it is now more critical than ever to sustain teachers. Consequently, the purpose of this study is to understand which mentoring experiences and induction support can aid in this objective. Framed by Bakhtin’s theory of dialogism, this study's longitudinal, qualitative nature explores the experiences of novice teachers (NTs) in elementary schools in the United States whose critical first years occurred amid a global pandemic. More specifically, we focus on the formal and informal support they experienced while becoming a teacher. Analysis of the data, which included in-depth interviews with the NTs revealed two key themes: 1) deprioritizing mentoring, and 2) inconsistencies in mentoring. The implications of this study aim to extend the existing literature, offering action-based evidence to improve mentoring and induction. Focusing on the retention of NTs via support and mentoring benefits the field now and into the future
Balancing the Art and Science of Archival Processing Metrics and Assessment
At the University of Nevada, Las Vegas (UNLV) University Libraries, archival processing metrics are used to support value propositions, project proposals, project management, and strategic planning. When making data-driven decisions, UNLV Special Collections Technical Services staff strive to balance the art and science of archival processing metrics—to critically assess their data and look beyond the numbers for additional information that brings meaning to the metrics. In this research paper, the authors review processing metrics across the profession and place their own archival processing field data within the context of more than three decades of professional practice. They report and explore UNLV’s processing rates and the variables that potentially influence their rates. Learning from methods piloted during special projects, they reach toward a more streamlined, sustainable assessment practice. They also include a “work in progress”—an experimental framework that suggests core processing data points for UNLV with a second tier of optional data points that may add value to metrics in specific circumstances. The flexibility and extensibility of the framework give it the potential to serve as a model for other repositories
A Pixel Vertex Tracker for the TESLA Detector
In order to fully exploit the physics potential of a e+e- linear collider,
such as TESLA, a Vertex Tracker providing high resolution track reconstruction
is required. Hybrid Silicon pixel sensors are an attractive sensor technology
option due to their read-out speed and radiation hardness, favoured in the high
rate TESLA environment, but have been so far limited by the achievable single
point space resolution. A novel layout of pixel detectors with interleaved
cells to improve their spatial resolution is introduced and the results of the
characterisation of a first set of test structures are discussed. In this note,
a conceptual design of the TESLA Vertex Tracker, based on hybrid pixel sensors
is presentedComment: 20 pages, 11 figure
REVIEWING THE ROOTS OF RESPONSE TO INTERVENTION:IS THERE ENOUGH RESEARCH TO SUPPORT THE PROMISE?
In the United States, Response to Intervention (RtI) is used to promote the use of evidence-based instruction in educational institutions, with the goal of supporting general and specialized educators and enabling these professionals to work together in a comprehensive, integrated manner. In doing so, RtI provides a protocol for identifying students with specific academic deficits and who demonstrate the need for individualized forms of instruction. Specifically, professional educators utilize quantitative data accumulated from common student assessment scores, which is thought to reflect a student’s response to instruction in the general classroom, in addition to his or her response to more targeted forms of intervention. This article presents a conceptual overview of RtI and discusses key dimensions most salient to its development and implementation within the United States, while carefully reviewing the research supporting the effectiveness of this multi-tiered framework. As RtI gains prominence in other countries, this article serves to educate others on what may well become a more universal response to intervention
High Resolution Hybrid Pixel Sensors for the e+e- TESLA Linear Collider Vertex Tracker
In order to fully exploit the physics potential of a future high energy e+e-
linear collider, a Vertex Tracker, providing high resolution track
reconstruction, is required. Hybrid Silicon pixel sensors are an attractive
option, for the sensor technology, due to their read-out speed and radiation
hardness, favoured in the high rate environment of the TESLA e+e- linear
collider design but have been so far limited by the achievable single point
space resolution. In this paper, a conceptual design of the TESLA Vertex
Tracker, based on a novel layout of hybrid pixel sensors with interleaved cells
to improve their spatial resolution, is presented.Comment: 12 pages, 5 figures, to appear in the Proceedings of the Vertex99
Workshop, Texel (The Netherlands), June 199
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