113 research outputs found
Status of Muon Collider Research and Development and Future Plans
The status of the research on muon colliders is discussed and plans are
outlined for future theoretical and experimental studies. Besides continued
work on the parameters of a 3-4 and 0.5 TeV center-of-mass (CoM) energy
collider, many studies are now concentrating on a machine near 0.1 TeV (CoM)
that could be a factory for the s-channel production of Higgs particles. We
discuss the research on the various components in such muon colliders, starting
from the proton accelerator needed to generate pions from a heavy-Z target and
proceeding through the phase rotation and decay ()
channel, muon cooling, acceleration, storage in a collider ring and the
collider detector. We also present theoretical and experimental R & D plans for
the next several years that should lead to a better understanding of the design
and feasibility issues for all of the components. This report is an update of
the progress on the R & D since the Feasibility Study of Muon Colliders
presented at the Snowmass'96 Workshop [R. B. Palmer, A. Sessler and A.
Tollestrup, Proceedings of the 1996 DPF/DPB Summer Study on High-Energy Physics
(Stanford Linear Accelerator Center, Menlo Park, CA, 1997)].Comment: 95 pages, 75 figures. Submitted to Physical Review Special Topics,
Accelerators and Beam
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Predicting breast cancer response to neoadjuvant treatment using multi-feature MRI: results from the I-SPY 2 TRIAL.
Dynamic contrast-enhanced (DCE) MRI provides both morphological and functional information regarding breast tumor response to neoadjuvant chemotherapy (NAC). The purpose of this retrospective study is to test if prediction models combining multiple MRI features outperform models with single features. Four features were quantitatively calculated in each MRI exam: functional tumor volume, longest diameter, sphericity, and contralateral background parenchymal enhancement. Logistic regression analysis was used to study the relationship between MRI variables and pathologic complete response (pCR). Predictive performance was estimated using the area under the receiver operating characteristic curve (AUC). The full cohort was stratified by hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) status (positive or negative). A total of 384 patients (median age: 49 y/o) were included. Results showed analysis with combined features achieved higher AUCs than analysis with any feature alone. AUCs estimated for the combined versus highest AUCs among single features were 0.81 (95% confidence interval [CI]: 0.76, 0.86) versus 0.79 (95% CI: 0.73, 0.85) in the full cohort, 0.83 (95% CI: 0.77, 0.92) versus 0.73 (95% CI: 0.61, 0.84) in HR-positive/HER2-negative, 0.88 (95% CI: 0.79, 0.97) versus 0.78 (95% CI: 0.63, 0.89) in HR-positive/HER2-positive, 0.83 (95% CI not available) versus 0.75 (95% CI: 0.46, 0.81) in HR-negative/HER2-positive, and 0.82 (95% CI: 0.74, 0.91) versus 0.75 (95% CI: 0.64, 0.83) in triple negatives. Multi-feature MRI analysis improved pCR prediction over analysis of any individual feature that we examined. Additionally, the improvements in prediction were more notable when analysis was conducted according to cancer subtype
Major Role of Microbes in Carbon Fluxes during Austral Winter in the Southern Drake Passage
Carbon cycling in Southern Ocean is a major issue in climate change, hence the need to understand the role of biota in the regulation of carbon fixation and cycling. Southern Ocean is a heterogeneous system, characterized by a strong seasonality, due to long dark winter. Yet, currently little is known about biogeochemical dynamics during this season, particularly in the deeper part of the ocean. We studied bacterial communities and processes in summer and winter cruises in the southern Drake Passage. Here we show that in winter, when the primary production is greatly reduced, Bacteria and Archaea become the major producers of biogenic particles, at the expense of dissolved organic carbon drawdown. Heterotrophic production and chemoautotrophic CO2 fixation rates were substantial, also in deep water, and bacterial populations were controlled by protists and viruses. A dynamic food web is also consistent with the observed temporal and spatial variations in archaeal and bacterial communities that might exploit various niches. Thus, Southern Ocean microbial loop may substantially maintain a wintertime food web and system respiration at the expense of summer produced DOC as well as regenerate nutrients and iron. Our findings have important implications for Southern Ocean ecosystem functioning and carbon cycle and its manipulation by iron enrichment to achieve net sequestration of atmospheric CO2
Reading and Ownership
First paragraph: ‘It is as easy to make sweeping statements about reading tastes as to indict a nation, and as pointless.’ This jocular remark by a librarian made in the Times in 1952 sums up the dangers and difficulties of writing the history of reading. As a field of study in the humanities it is still in its infancy and encompasses a range of different methodologies and theoretical approaches. Historians of reading are not solely interested in what people read, but also turn their attention to the why, where and how of the reading experience. Reading can be solitary, silent, secret, surreptitious; it can be oral, educative, enforced, or assertive of a collective identity. For what purposes are individuals reading? How do they actually use books and other textual material? What are the physical environments and spaces of reading? What social, educational, technological, commercial, legal, or ideological contexts underpin reading practices? Finding answers to these questions is compounded by the difficulty of locating and interpreting evidence. As Mary Hammond points out, ‘most reading acts in history remain unrecorded, unmarked or forgotten’. Available sources are wide but inchoate: diaries, letters and autobiographies; personal and oral testimonies; marginalia; and records of societies and reading groups all lend themselves more to the case-study approach than the historical survey. Statistics offer analysable data but have the effect of producing identikits rather than actual human beings. The twenty-first century affords further possibilities, and challenges, with its traces of digital reader activity, but the map is ever-changing
Schoolbooks and textbook publishing.
In this chapter the author looks at the history of schoolbooks and textbook publishing. The nineteenth century saw a rise in the school book market in Britain due to the rise of formal schooling and public examinations. Although the 1870 Education and 1872 (Scotland) Education Acts made elementary education compulsory for childern between 5-13 years old, it was not until the end of the First World War that some sort form of secondary education became compulsory for all children
The Positive Impact of Conservation Action
Governments recently adopted new global targets to halt and reverse the loss of biodiversity. It is therefore crucial to understand the outcomes of conservation actions. We conducted a global meta-analysis of 186 studies (including 665 trials) that measured biodiversity over time and compared outcomes under conservation action with a suitable counterfactual of no action. We find that in two-thirds of cases, conservation either improved the state of biodiversity or at least slowed declines. Specifically, we find that interventions targeted at species and ecosystems, such as invasive species control, habitat loss reduction and restoration, protected areas, and sustainable management, are highly effective and have large effect sizes. This provides the strongest evidence to date that conservation actions are successful but require transformational scaling up to meet global targets
When the Shoe is on the Other Foot: Experimental Evidence on Evaluation Disparities
Research provides evidence that the method chosen to elicit value has an important effect on a person’s valuation. We hypothesize that role has a crucial effect on decision makers’ elicited values: Buyers prefer to pay less and sellers prefer to collect more. We conduct experimental sessions and replicate the disparity between willingness to pay and willingness to accept. We conduct additional sessions in which role is stripped away: Endowed decision makers provide values that are used to determine a price at which anonymous others transact. Importantly, decision makers’ earnings in the experiment are not affected by the elicited values, but the endowments influence decision makers’ valuations. Our findings suggest that decision makers consider their relative standing, in comparison to anonymous others, in providing valuations. The disparity between willingness to pay and willingness to accept disappears when decision makers’ endowments ensure that they are at least as well off as other participants
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