4,282 research outputs found
Post-selection point and interval estimation of signal sizes in Gaussian samples
We tackle the problem of the estimation of a vector of means from a single
vector-valued observation . Whereas previous work reduces the size of the
estimates for the largest (absolute) sample elements via shrinkage (like
James-Stein) or biases estimated via empirical Bayes methodology, we take a
novel approach. We adapt recent developments by Lee et al (2013) in post
selection inference for the Lasso to the orthogonal setting, where sample
elements have different underlying signal sizes. This is exactly the setup
encountered when estimating many means. It is shown that other selection
procedures, like selecting the largest (absolute) sample elements and the
Benjamini-Hochberg procedure, can be cast into their framework, allowing us to
leverage their results. Point and interval estimates for signal sizes are
proposed. These seem to perform quite well against competitors, both recent and
more tenured.
Furthermore, we prove an upper bound to the worst case risk of our estimator,
when combined with the Benjamini-Hochberg procedure, and show that it is within
a constant multiple of the minimax risk over a rich set of parameter spaces
meant to evoke sparsity.Comment: 27 pages, 13 figure
Intestinal and systemic cytotoxic T lymphocyte and humoral immune responses to oral and parenteral reovirus infection
This work was undertaken to determine effects of routes of infection with reovirus induction of responder cytotoxic T lymphocytes (CTL). Further, this work concerns differential effects of age on humoral and CTL responses following oral and parenteral reovirus infection. Despite considerable knowledge about non-intestinal systemic viral immunity, intestinal immune response to viral infection is less understood, and it remains unknown what differences, may occur in CTL populations induced by local viral infections in the intestine or systemic periphery.;We infected mice orally or in hind footpads with reovirus, serotype 1, strain Lang (TIL), and utilized flow cytometry to assess T cell receptor (TCR) Vbeta repertoire of CD8+ cells in draining lymphoid tissues and spleens for reovirus-driven proliferative changes. We observed predominant expansion of Vbeta6+ CD8+ CTL in spleens and Peyer\u27s patches (PP) of orally infected mice, as well as spleens and popliteal lymph nodes of footpad infected mice. Vbeta6+ CD8 + cells from orally and footpad infected mice mediated reovirus-specific cytotoxicity. TCR beta chain complementarity determining region 3beta (CDR3beta length profile analysis of Vbeta6+ CD8 + cell lines from orally and footpad infected mice, as well as cells recovered from adoptive transfer into reovirus infected SCID recipients, showed a consistent, clear, and uniform expansion of one or few clones bearing identical CDR3beta length, indicating that CTL responses following oral or parenteral infection are likely dominated by identical CTL populations.;We also compared the ability of old and young mice to mount CTL and humoral responses to reovirus. We found old and young mice had similar CTL frequency and cytotoxicity following oral and parenteral infection. We observed that while old mice mounted IgG responses to parenteral reovirus equivalent to young mice, IgA responses of orally infected aged mice were elevated compared to young mice. These data indicate old mice retain the ability to mount CTL and humoral responses against reovirus in the intestine and systemic periphery. Furthermore, old mice have potentiation of intestinal IgA responses compared to young following intestinal infection. Our results suggest the intestine can be utilized as a route of immunization to provide efficacious cell-mediated and humoral immunity in the aged
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Into the bargain : the triumph and tragedy of nuclear internationalism during the mid-Cold War, 1958-1970
The making of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) occupied the energy and attention of world powers, great and small, from the Irish Resolution’s proposal at the United Nations General Assembly in 1958 to the treaty’s entry into force in 1970. Accounts of why the international community fashioned a treaty whose articles and principles embody a tangle of self-contradictory rights, privileges, and obligations point to United States and Soviet hegemony, the rise of Soviet-American détente, or the intrinsic dangers of nuclear weapons. In contrast to these interpretations, this dissertation claims that the negotiation and achievement of the NPT was a contingent event whose course and content were shaped by a jumble of entangled causes: Cold War alliances, domestic politics, decolonization, the Vietnam War, and a schism in internationalist thought. The common impulse, however, was the perceived need to bring order to the Nuclear Age amid recurrent crises whose outbreak threatened global conflict if the spread of nuclear weapons continued unabated. In the contexts of the Cold War and decolonization, the establishment of a global nuclear order required Soviet-American cooperation in concert with the involvement of an international community then emerging from decolonization. Both were embodied in the cadre of arms control diplomats then working in Geneva and New York City. In the final analysis, the Cold War obstructed more than it abetted the treaty’s brokering and Soviet-American détente was more the result of international nuclear diplomacy than its cause. The Vietnam War both limited U.S. willingness to contemplate nuclear assurances requested by nuclear have-nots and the underlying reason that U.S. President Lyndon Johnson sacrificed a NATO multilateral nuclear force for the sake of an NPT in an effort to quiet antiwar dissent at home. Soviet-American cooperation was necessary but not sufficient to achieve the treaty. The failure of initial efforts, the international consensus required to legitimate the treaty, and concurrent talks for a Latin American nuclear-free zone allowed nuclear have-nots to inscribe their preferences on the NPT, whose fusion of a nuclear hierarchy and a grand bargain remains an open chapter in the history of nuclear internationalism.Histor
Complete intersection singularities of splice type as universal abelian covers
It has long been known that every quasi-homogeneous normal complex surface
singularity with Q-homology sphere link has universal abelian cover a Brieskorn
complete intersection singularity. We describe a broad generalization: First,
one has a class of complete intersection normal complex surface singularities
called "splice type singularities", which generalize Brieskorn complete
intersections. Second, these arise as universal abelian covers of a class of
normal surface singularities with Q-homology sphere links, called
"splice-quotient singularities". According to the Main Theorem,
splice-quotients realize a large portion of the possible topologies of
singularities with Q-homology sphere links. As quotients of complete
intersections, they are necessarily Q-Gorenstein, and many Q-Gorenstein
singularities with Q-homology sphere links are of this type. We conjecture that
rational singularities and minimally elliptic singularities with Q-homology
sphere links are splice-quotients. A recent preprint of T Okuma presents
confirmation of this conjecture.Comment: Published by Geometry and Topology at
http://www.maths.warwick.ac.uk/gt/GTVol9/paper17.abs.htm
Guiding Transformation: How Medical Practices Can Become Patient-Centered Medical Homes
Describes in detail eight change concepts as a guide to transforming a practice into a patient-centered medical home, including engaged leadership, quality improvement strategy, continuous and team-based healing relationships, and enhanced access
Influence of organic films on the evaporation and condensation of water in aerosol
Uncertainties in quantifying the kinetics of evaporation and condensation of water from atmospheric aerosol are a significant contributor to the uncertainty in predicting cloud droplet number and the indirect effect of aerosols on climate. The influence of aerosol particle surface composition, particularly the impact of surface active organic films, on the condensation and evaporation coefficients remains ambiguous. Here, we report measurements of the influence of organic films on the evaporation and condensation of water from aerosol particles. Significant reductions in the evaporation coefficient are shown to result when condensed films are formed by monolayers of long-chain alcohols [C(n)H((2n+1))OH], with the value decreasing from 2.4 × 10(−3) to 1.7 × 10(−5) as n increases from 12 to 17. Temperature-dependent measurements confirm that a condensed film of long-range order must be formed to suppress the evaporation coefficient below 0.05. The condensation of water on a droplet coated in a condensed film is shown to be fast, with strong coherence of the long-chain alcohol molecules leading to islanding as the water droplet grows, opening up broad areas of uncoated surface on which water can condense rapidly. We conclude that multicomponent composition of organic films on the surface of atmospheric aerosol particles is likely to preclude the formation of condensed films and that the kinetics of water condensation during the activation of aerosol to form cloud droplets is likely to remain rapid
Argumentación compleja en Educación Primaria
This paper describes a study of mathematical argumentation in primary school. The principal aim is to explore the nature of complex argumentation at a structural level. The context of the study was a teaching experiment involving nine tasks that promoted argumentation among fifth graders. We use the framework and method of reconstructing complex argumentation in the classroom proposed by Knipping (2008). The findings show that complex argumentation at a structural level in the context of refuting conclusions is characterized by a source-like structure with the addition of a new refutation argument element.Este artículo describe un estudio de argumentación matemática en educación primaria. El objetivo principal es explorar la naturaleza de la argumentación compleja en un nivel estructural. El contexto del estudio fue un experimento de enseñanza con nueve tareas que promovieron la argumentación entre estudiantes de quinto grado. Usamos el marco teórico y metodológico para reconstruir la argumentación compleja en el salón de clase propuesto por Knipping (2003). Los resultados muestran que la argumentación compleja a nivel estructural en el contexto de refutar conclusiones se caracteriza por ser una estructura de
fuente con el agregado de un argumento de refutación
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