1,914 research outputs found
Estimating spillovers using imprecisely measured networks
In many experimental contexts, whether and how network interactions impact
the outcome of interest for both treated and untreated individuals are key
concerns. Networks data is often assumed to perfectly represent these possible
interactions. This paper considers the problem of estimating treatment effects
when measured connections are, instead, a noisy representation of the true
spillover pathways. We show that existing methods, using the potential outcomes
framework, yield biased estimators in the presence of this mismeasurement. We
develop a new method, using a class of mixture models, that can account for
missing connections and discuss its estimation via the Expectation-Maximization
algorithm. We check our method's performance by simulating experiments on real
network data from 43 villages in India. Finally, we use data from a previously
published study to show that estimates using our method are more robust to the
choice of network measure
Adversity-related experiences are essential for Olympic success: additional evidence and considerations
Drawing on Hardy et al.'s study as the target article, in this commentary, we focus on the adversity-related experiences and consequences of the Olympic and/or World champions that they sampled. With this in mind, we divide the narrative into two main sections. In the first section, we explore the association between adversity-related experiences and Olympic success, and provide additional evidence in support of the notion that adversity-related experiences are essential for success at the highest level of sport. In the second section, we discuss the role of adversity-related experiences in Olympic success considering a series of important psychosocial processes that are required for superior performance. In ending, we reflect on the salient (contentious and ethical) issues in the study and practice of adversity-related experiences and sport performance. We hope that our commentary adds to the extant literature and is useful for future study and practice in performance sport
Nancy Meleski Collection - Accession 1566
The Nancy Meleski Collection contains a family bible with names of people who got married, were born, and died, a family dictionary that contains names of people and towns, and a collection of sheet music for vocals, violin, and piano. Names and places listed in the family bible are: Moses F. Hardy, Amanda Kineeskern, Seward Valley, New York, Stefhen P. Brewster, Julia Holly, Amanda Hardy, William Eben Hardy, Parley Elmer Hardy, Katharine Melinda Brewster, and Rhoby Jennings. People and places listed in the family dictionary are: Volney, New York, Schroeppel, New York, Chauncy Morgan, Palermo Morgan, Albert Morgan, Richard Holly, and Marie Holly Woods.https://digitalcommons.winthrop.edu/manuscriptcollection_findingaids/2625/thumbnail.jp
Projections for measuring the size of the solar core with neutrino-electron scattering
We quantify the amount of data needed in order to measure the size and
position of the B neutrino production region within the solar core, for
experiments looking at elastic scattering between electrons and solar
neutrinos. The directions of the electrons immediately after scattering are
strongly correlated with the incident directions of the neutrinos, however this
is degraded significantly by the subsequent scattering of these electrons in
the detector medium. We generate distributions of such electrons for different
neutrino production profiles, and use a maximum likelihood analysis to make
projections for future experimental sensitivity. We find that with
approximately 20 years worth of data the Super Kamiokande experiment could
constrain the central radius of the shell in which B neutrinos are produced
to be less than 0.22 of the total solar radius at 95% confidence.Comment: 5 pages, 2 figures. Matches version accepted to PRL. Improved 2D
analysis and results discussio
Superfluid Density in a Highly Underdoped YBCO Superconductor
The superfluid density rho_s(T) = 1/lambda^2(T) has been measured at 2.64 GHz
in highly underdoped YBCO, at 37 dopings with T_c between 3 K and 17 K. Within
limits set by the transition width Delta T_c ~ 0.4 K, rho_s(T) shows no
evidence of critical fluctuations as T goes to T_c, with a mean-field-like
transition and no indication of vortex unbinding. Instead, we propose that
rho_s displays the behaviour expected for a quantum phase transition in the (3
+ 1)-dimensional XY universality class, with rho_s0 ~ (p - p_c), T_c ~ (p -
p_c)^1/2 and rho_s(T) ~ (T_c - T)^1 as T goes to T_c.Comment: 4 pages, 5 figures; final version of pape
Apparatus for high resolution microwave spectroscopy in strong magnetic fields
We have developed a low temperature, high-resolution microwave surface
impedance probe that is able to operate in high static magnetic fields. Surface
impedance is measured by cavity perturbation of dielectric resonators, with
sufficient sensitivity to resolve the microwave absorption of sub-mm-sized
superconducting samples. The resonators are constructed from high permittivity
single-crystal rutile (TiO2) and have quality factors in excess of 10^6.
Resonators with such high performance have traditionally required the use of
superconducting materials, making them incompatible with large magnetic fields
and subject to problems associated with aging and power-dependent response.
Rutile resonators avoid these problems while retaining comparable sensitivity
to surface impedance. Our cylindrical rutile resonators have a hollow bore and
are excited in TE_01(n-d) modes, providing homogeneous microwave fields at the
center of the resonator where the sample is positioned. Using a sapphire
hot-finger technique, measurements can be made at sample temperatures in the
range 1.1 K to 200 K, while the probe itself remains immersed in a liquid
helium bath at 4.2 K. The novel apparatus described in this article is an
extremely robust and versatile system for microwave spectroscopy, integrating
several important features into a single system. These include: operation at
high magnetic fields; multiple measurement frequencies between 2.64 GHz and
14.0 GHz in a single resonator; excellent frequency stability, with typical
drifts < 1 Hz per hour; the ability to withdraw the sample from the resonator
for background calibration; and a small pot of liquid helium separate from the
external bath that provides a sample base temperature of 1.1 K.Comment: 10 pages, 5 figure
Bolometric technique for high-resolution broadband microwave spectroscopy of ultra-low-loss samples
A novel low temperature bolometric method has been devised and implemented
for high-precision measurements of the microwave surface resistance of small
single-crystal platelet samples having very low absorption, as a continuous
function of frequency. The key to the success of this non-resonant method is
the in-situ use of a normal metal reference sample that calibrates the absolute
rf field strength. The sample temperature can be controlled independently of
the 1.2 K liquid helium bath, allowing for measurements of the temperature
evolution of the absorption. However, the instrument's sensitivity decreases at
higher temperatures, placing a limit on the useful temperature range. Using
this method, the minimum detectable power at 1.3 K is 1.5 pW, corresponding to
a surface resistance sensitivity of 1 for a typical 1
mm1 mm platelet sample.Comment: 13 pages, 12 figures, submitted to Review of Scientific Instrument
Policing vulnerability through building community connections
Most people who come into contact with the Police Service can be described, in some way or other, as
vulnerable. Victims, offenders, witnesses, and bystanders are all exposed to social conflict and attempts by the police to
restore order. Thus, while vulnerability is context-specific it is largely defined via deficit frameworks that view individuals
and groups as marginalized or disadvantaged and requiring immediate intervention. This framework is expensive,
risk-averse, and often counter-productive for police and associated agencies. The policy push for demand
reduction amongst policing agencies offers an opportunity to re-evaluate this approach and to identify and mobilize
local assets that can support vulnerable populations. This article draws on the literature on addictions and recovery to
explore the networks of support available to vulnerable populations and the potential mechanisms this presents for the
development of assertive linkages, community capacity, and self-policing
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