We conduct frequency comparisons between a state-of-the-art strontium optical lattice clock, a cryogenic crystalline silicon cavity, and a hydrogen maser to set new bounds on the coupling of ...ultralight dark matter to standard model particles and fields in the mass range of 10−16−10−21 eV. The key advantage of this two-part ratio comparison is the differential sensitivity to time variation of both the fine-structure constant and the electron mass, achieving a substantially improved limit on the moduli of ultralight dark matter, particularly at higher masses than typical atomic spectroscopic results. Furthermore, we demonstrate an extension of the search range to even higher masses by use of dynamical decoupling techniques. These results highlight the importance of using the best-performing atomic clocks for fundamental physics applications, as all-optical timescales are increasingly integrated with, and will eventually supplant, existing microwave timescales.
We explore how accurate earthquake early warning (EEW) can be, given our limited ability to forecast expected shaking even if the earthquake source is known. Because of the strong variability of ...ground motion metrics, such as peak ground acceleration (PGA) and peak ground velocity (PGV), we find that correct alerts (i.e., alerts that accurately estimate the ground motion will be above a predetermined damage threshold) are not expected to be the most common EEW outcome even when the earthquake magnitude and location are accurately determined. Infrequently, ground motion variability results in a user receiving a false alert because the ground motion turned out to be significantly smaller than the system expected. More commonly, users will experience missed alerts when the system does not issue an alert but the user experiences potentially damaging shaking. Despite these inherit limitations, EEW can significantly mitigate earthquake losses for false-alert-tolerant users who choose to receive alerts for expected ground motions much smaller than the level that could cause damage. Although this results in many false alerts (unnecessary alerts for earthquakes that do not produce damaging ground shaking), it minimizes the number of missed alerts and produces overall optimal performance.
Electron-Ion Collider: The next QCD frontier Accardi, A; Albacete, J L; Anselmino, M ...
European physical journal. A, Hadrons and nuclei,
09/2016, Volume:
52, Issue:
9
Journal Article
Peer reviewed
Open access
This White Paper presents the science case of an Electron-Ion Collider (EIC), focused on the structure and interactions of gluon-dominated matter, with the intent to articulate it to the broader ...nuclear science community. It was commissioned by the managements of Brookhaven National Laboratory (BNL) and Thomas Jefferson National Accelerator Facility (JLab) with the objective of presenting a summary of scientific opportunities and goals of the EIC as a follow-up to the 2007 NSAC Long Range plan. This document is a culmination of a community-wide effort in nuclear science following a series of workshops on EIC physics over the past decades and, in particular, the focused ten-week program on “Gluons and quark sea at high energies” at the Institute for Nuclear Theory in Fall 2010. It contains a brief description of a few golden physics measurements along with accelerator and detector concepts required to achieve them. It has been benefited profoundly from inputs by the users’ communities of BNL and JLab. This White Paper offers the promise to propel the QCD science program in the US, established with the CEBAF accelerator at JLab and the RHIC collider at BNL, to the next QCD frontier.
We report on the first timescale based entirely on optical technology. Existing timescales, including those incorporating optical frequency standards, rely exclusively on microwave local oscillators ...owing to the lack of an optical oscillator with the required frequency predictability and stability for reliable steering. We combine a cryogenic silicon cavity exhibiting improved long-term stability and an accurate Sr87 lattice clock to form a timescale that outperforms them all. Our timescale accumulates an estimated time error of only 48±94 ps over 34 days of operation. Our analysis indicates that this timescale is capable of reaching a stability below 1×10−17 after a few months of averaging, making timekeeping at the 10−18 level a realistic prospect.
Cisplatin is a platinum chemotherapeutic used in a variety of malignancies. The antineoplastic activity occurs from DNA cross-links and adducts, in addition to the generation of superoxide radicals. ...Nephrotoxicity is the most well-known and potentially most clinically significant toxicity. Unfortunately, the mechanism for cisplatin nephrotoxicity has not been completely elucidated; however, many theories have been developed. Other toxicities include gastrointestinal, myelosuppression, ototoxicity and neurotoxicity. Saline diuresis is currently the most accepted way to prevent cisplatin nephrotoxicity. Research has focused on pharmaceuticals and enzyme/molecular alterations as alternatives to long-term diuresis. No agents have currently been identified that can protect from all toxicities. Cisplatin has shown activity against osteosarcoma, transitional cell carcinoma, squamous cell carcinoma (SCC), melanoma, mesothelioma, carcinomatosis and germinal cell tumours in the dog. In the cat, cisplatin cannot be utilized because of fulminant pulmonary oedema that occurs at standard doses. Intralesional cisplatin has been utilized in horses for the treatment of SCC and sarcoids.
Mature trees are declining faster than they are being replaced in landscapes managed for agriculture, wood production and residential development. Population bottlenecks are therefore predicted for ...biota that depends on mature trees. We erected five utility poles and five large dead trees to evaluate whether artificial structures can offset the loss of living mature trees from a residential development. We implemented the study as a before-after-control-impact (BACI) experiment that included five control sites with no trees and five sites with living mature trees—sampled before and soon after the artificial structures were erected. Bird species richness increased significantly where utility poles or dead trees were erected with no significant change at control sites or at living mature trees. Erecting dead trees provided the greatest gain in bird species richness and was also more cost-effective than erecting utility poles or planting seedlings and waiting for them to mature. However, dead trees did not support as many native bird species as living mature trees and 37% of the species observed in our study occurred exclusively at living mature trees indicating that erecting dead trees or utility poles is only a partial solution for offsetting the loss of mature trees. Our results suggest that conserving all birds where mature trees are declining requires a complementary strategy of: (a) protecting as many living mature trees as possible, (b) recruiting a new cohort of future mature trees by establishing seedlings; and (c) erecting artificial structures to provide suitable habitat until these seedlings reach maturity.
•We recorded substantial increases in bird species richness where utility poles and dead trees were erected.•Erecting these structures was a more cost-effective way to increase bird species richness than planting seedlings.•However, not all bird species responded—some only occurred where living mature trees persist in the landscape.
Møller scattering is one of the most fundamental processes in QED, and a variety of modern experiments require its knowledge to high precision. A recent calculation considered the radiative process ...at low energy, where the electron mass cannot be neglected. To test the calculation, an experiment was carried out using the Van de Graaff accelerator at the MIT High Voltage Research Laboratory. Momentum spectra at three scattering angles are reported here and compared to simulation, based on our previous calculation. Good agreement between the measurements and our calculation is observed.
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