2,458 research outputs found
Stresses in the material with multilayered coating under impulse thermal loading
The two-dimensional model of mechanical behavior of the specimen with multi layered coating is formulated. The parametric analysis was carried out for various types of boundary conditions. Stress intensity depending on time was studied. The influence of impulse parameters on the temperature and stresses was investigated. It was revealed that radiation heat losses reduces the action of external loading
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Changes in epithelial proportions and transcriptional state underlie major premenopausal breast cancer risks
The human breast undergoes lifelong remodeling in response to estrogen and progesterone, but hormone exposure also increases breast cancer risk. Here, we use single-cell analysis to identify distinct mechanisms through which breast composition and cell state affect hormone signaling. We show that prior pregnancy reduces the transcriptional response of hormone-responsive (HR+) epithelial cells, whereas high body mass index (BMI) reduces overall HR+ cell proportions. These distinct changes both impact neighboring cells by effectively reducing the magnitude of paracrine signals originating from HR+ cells. Because pregnancy and high BMI are known to protect against hormone-dependent breast cancer in premenopausal women, our findings directly link breast cancer risk with person-to-person heterogeneity in hormone responsiveness. More broadly, our findings illustrate how cell proportions and cell state can collectively impact cell communities through the action of cell-to-cell signaling networks
Microwave Schottky diagnostic systems for the Fermilab Tevatron, Recycler, and CERN LHC
A means for non-invasive measurement of transverse and longitudinal
characteristics of bunched beams in synchrotrons has been developed based on
high sensitivity slotted waveguide pickups. The pickups allow for bandwidths
exceeding hundreds of MHz while maintaining good beam sensitivity
characteristics. Wide bandwidth is essential to allow bunch-by-bunch
measurements by means of a fast gate. The Schottky detector system is installed
and successfully commissioned in the Fermilab Tevatron, Recycler and CERN LHC
synchrotrons. Measurement capabilities include tune, chromaticity, and momentum
spread of single or multiple beam bunches in any combination. With appropriate
calibrations, emittance can also be measured by integrating the area under the
incoherent tune sidebands
Assessing NARCCAP climate model effects using spatial confidence regions
We assess similarities and differences between model effects for the North American Regional
Climate Change Assessment Program (NARCCAP) climate models using
varying classes of linear regression models. Specifically, we
consider how the average temperature effect differs for the various
global and regional climate model combinations, including assessment
of possible interaction between the effects of global and regional
climate models. We use both pointwise and simultaneous inference
procedures to identify regions where global and regional climate model effects differ. We also show
conclusively that results from pointwise inference are misleading, and
that accounting for multiple comparisons is important for making
proper inference
Effect of microstructures on the electron-phonon interaction in the disordered metals PdAg
Using the weak-localization method, we have measured the electron-phonon
scattering times in PdAg thick films prepared by DC-
and RF-sputtering deposition techniques. In both series of samples, we find an
anomalous temperature and disorder dependence,
where is the electron elastic mean free path. This anomalous behavior
cannot be explained in terms of the current concepts for the electron-phonon
interaction in impure conductors. Our result also reveals that the strength of
the electron-phonon coupling is much stronger in the DC than RF sputtered
films, suggesting that the electron-phonon interaction not only is sensitive to
the total level of disorder but also is sensitive to the microscopic quality of
the disorder.Comment: accepted for publication in Phys. Rev.
Simulations of the TJNAF FEL with tapered and inversely tapered undulators
Experiments using the TJNAF FEL have explored the operation with both tapered and inversely tapered undulators.
We present here numerical simulations using the TJNAF experimental parameters, including the effects of taper. Singlemode
simulations show the effect of taper on gain. Multimode simulations describe the evolution of short optical pulses
in the far infrared, and show how taper affects single-pass gain and steady-state power as a function of desynchronism.
A short optical pulse presents an ever-changing field strength to each section of the electron pulse so that idealized
operation is not possible. Yet, advantages for the recirculation of the electron beam can be explored.The authors are grateful for support by the Naval Postgraduate School
Beam instrumentation for the Tevatron Collider
The Tevatron in Collider Run II (2001-present) is operating with six times
more bunches and many times higher beam intensities and luminosities than in
Run I (1992-1995). Beam diagnostics were crucial for the machine start-up and
the never-ending luminosity upgrade campaign. We present the overall picture of
the Tevatron diagnostics development for Run II, outline machine needs for new
instrumentation, present several notable examples that led to Tevatron
performance improvements, and discuss the lessons for future colliders
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