1.9 picosecond high‐sensitivity sampling optical temporal analyzer

An all solid‐state, high‐sensitivity sampling optical temporal analyzer has been demonstrated by integrating two interdigitated picosecond metal‐semiconductor‐metal photodetectors into a coplanar transmission line structure. The full width at half‐maximum of the response time is 1.9 ps. The noise equivalent optical power is 500 pW, and the dynamic range is more than 60 dB.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69890/2/APPLAB-64-5-551-1.pd

Fast rates in statistical and online learning

The speed with which a learning algorithm converges as it is presented with more data is a central problem in machine learning --- a fast rate of convergence means less data is needed for the same level of performance. The pursuit of fast rates in online and statistical learning has led to the discovery of many conditions in learning theory under which fast learning is possible. We show that most of these conditions are special cases of a single, unifying condition, that comes in two forms: the central condition for 'proper' learning algorithms that always output a hypothesis in the given model, and stochastic mixability for online algorithms that may make predictions outside of the model. We show that under surprisingly weak assumptions both conditions are, in a certain sense, equivalent. The central condition has a re-interpretation in terms of convexity of a set of pseudoprobabilities, linking it to density estimation under misspecification. For bounded losses, we show how the central condition enables a direct proof of fast rates and we prove its equivalence to the Bernstein condition, itself a generalization of the Tsybakov margin condition, both of which have played a central role in obtaining fast rates in statistical learning. Yet, while the Bernstein condition is two-sided, the central condition is one-sided, making it more suitable to deal with unbounded losses. In its stochastic mixability form, our condition generalizes both a stochastic exp-concavity condition identified by Juditsky, Rigollet and Tsybakov and Vovk's notion of mixability. Our unifying conditions thus provide a substantial step towards a characterization of fast rates in statistical learning, similar to how classical mixability characterizes constant regret in the sequential prediction with expert advice setting.Comment: 69 pages, 3 figure

The Quality of Open Source Production: Zealots and Good Samaritans in the Case of Wikipedia

New forms of production based in electronic technology, such as open-source and open-content production, convert private commodities (typically software) into essentially public goods. A number of studies find that, like in other collective goods, incentives for reputation and group identity motivate contributions to open source goods, thereby overcoming the social dilemma inherent in producing such goods. In this paper we examine how contributor motivations affect the quality of contributions to the open-content online encyclopedia Wikipedia. We find that quality is associated with contributor motivations, but in a surprisingly inconsistent way. Registered users\u27 quality increases with more contributions, consistent with the idea of participants motivated by reputation and commitment to the Wikipedia community. Surprisingly, however, we find the highest quality from the vast numbers of anonymous Good Samaritans who contribute only once. Our findings that Good Samaritans as well as committed zealots contribute high quality content to Wikipedia suggest that it is the quantity as well as the quality of contributors that positively affects the quality of open source production

The UK deficit-reduction strategy: evidence from 1979-2012

This paper examines the current financial crisis and the various tax-and-spend policies that affect the governments deficit-reduction strategy. The theory surrounding this is the Ricardian Equivalence Theorem, as set out by Robert Barro. The data is from various government sources between 1979 and 2017 and used in regression analysis and comparative cash analysis. The results indicate that, whilst tax and net public spending have contributed materially to levels of net borrowing and budget deficits, the most controversial issue of VAT has very little impact. The findings show that the underpinning theory does not hold in the UK under normal boom-and-bust circumstances but that this unusual financial crisis might prove the exception to the rule. The conclusion from all of the regressions run show that the key driver to reducing the deficit is economic growth, counteracting the major political parties traditional views of spending cuts or tax-and-spend policies

The UK deficit-reduction strategy: evidence from 1979-2012

This paper examines the current financial crisis and the various tax-and-spend policies that affect the governments deficit-reduction strategy. The theory surrounding this is the Ricardian Equivalence Theorem, as set out by Robert Barro. The data is from various government sources between 1979 and 2017 and used in regression analysis and comparative cash analysis. The results indicate that, whilst tax and net public spending have contributed materially to levels of net borrowing and budget deficits, the most controversial issue of VAT has very little impact. The findings show that the underpinning theory does not hold in the UK under normal boom-and-bust circumstances but that this unusual financial crisis might prove the exception to the rule. The conclusion from all of the regressions run show that the key driver to reducing the deficit is economic growth, counteracting the major political parties traditional views of spending cuts or tax-and-spend policies

Youth participation: Adultism, human rights and professional youth work

This article argues that the right of young people to participate in decisions being made about them forms the basis for professional youth work practice. The authors consider the nature of ‘participation’ and its relation to human rights, and introduces the concept of ‘adultism’ and the challenges for youth workers combatting ‘adultist’ beliefs and practices in the work of participation. The paper considers the benefits and limitations of youth participation models, and addresses the relationship between rights-based participation practice, and critical pedagogy (dialogical) in youth work

Youth participation: Adultism, human rights and professional youth work

This article argues that the right of young people to participate in decisions being made about them forms the basis for professional youth work practice. The authors consider the nature of ‘participation’ and its relation to human rights, and introduces the concept of ‘adultism’ and the challenges for youth workers combatting ‘adultist’ beliefs and practices in the work of participation. The paper considers the benefits and limitations of youth participation models, and addresses the relationship between rights-based participation practice, and critical pedagogy (dialogical) in youth work

Cosmic Ray Detection at the Murchison Radio-astronomy Observatory – a pathfinder for SKA-Low

We present the status of cosmic-ray detection activities at the Murchison Radio-astronomy Observatory. Using 128 antennas of the Murchison Widefield Array radio telescope in its extended configuration, we detect the radio emission from extensive air showers in the 122--154 MHz range at a rate of slightly less than once per hour, each with an approximate energy of 10$^{17}$ eV. We have developed a bespoke filter inversion to obtain high-time-resolution data from this general-purpose astronomy instrument, and directly capture the radio signal. Our future plans include the implementation of a particle-triggered mode, and expanded operations with the low-frequency component of the Square Kilometre Array, which will have ~100,000 antennas deployed on the same site

Crossing Many Boundaries in Creating Allies: Personal Encounters to Unfolding Science to Privilege Indigenous Knowledge

This paper discusses the challenges and experience of two faculty members (one Inuit, one White) as they seek to aid each other in fulfilling the institutional tenure track and program demands made upon them and as they seek to address how to engage teacher candidates in Indigenous knowledge and anti-racist education. There is discussion of practical action and resources for teaching anti-racism through privileging Indigenous knowledge and “unfolding” Eurocentric science, and of the ethical and philosophical challenges and what transpires in negotiating the individual and ethno-cultural difference of each faculty member through an Indigenous gaze (Ermine, 2007).ôta masinahikanis masinahâmok tânisi e-kî-isi-âyimihocik ôki nîso ataskeskesak (peyak ayaskîmow, peyak wâpiski-wîyâs)  ekwa mîna tânisi e-isi-wîcihitocik ôma kâ-masinahikehecik ekwa mina ôhi kiskinwahamâkana tânisi ka-isi-kiskinwahamawâcik iyiniw-kiskihtamowin ekwa namoya ka-pakwâtitohk. mâmiskôcikahtew tânisi ka-isi-atoskahtâkik ôma namoya ta-pakwâtitohk âpacihtâtwawi kihci-iyiniw-kiskihtamowin ekwa mina ka-taswekinamihk moniyawîpinikewin ekwa ta-kwe-miyo-wîpinike mâka ka-ahkâm-mâmawi-atoskâtamihk poko sôskwâc pakwâweyak ta-iyiniw-wâpahtekowisit