BeaverCube: Coastal Imaging with VIS/LWIR CubeSats

BeaverCube is a student-built 3U CubeSat that has two main objectives: one science objective and one technology objective. The science goal of BeaverCube is to demonstrate that it is possible to develop and apply platforms that can leverage statistical relationships between temperature and co-varying bio-optical properties, such as light absorption by colored dissolved organic matter. The technology goal of BeaverCube is to demonstrate electrospray propulsion for CubeSats, enabling more coordinated and targeted science missions among multiple spacecraft. The science objective for BeaverCube involves measuring temperature and color, which are key oceanographic properties, through a low-cost platform. Temperature and salinity are used to determine the density of watermasses. This is then used to physically classify them. Thermohaline circulation is a part of large-scale ocean circulation that is driven by global density gradients created by surface heat and freshwater fluxes. Thermohaline circulation plays an important role in supplying heat to the polar regions; it influences the rate of sea ice formation near the poles, which in turn affects other aspects of the climate system, such as the albedo, and thus solar heating, at high latitudes. Small- and meso-scale ocean features such as fronts and eddies canal so be identified and tracked solely using sea surface temperature properties. BeaverCube will track warm core rings on the Northeastern section of the US coast, one of the regions in the world that is heating the fastest due to climate change. Wide geospatial coverage with near-simultaneous measurements of thermal and bio-optical ocean properties by a CubeSat has the potential to address many important oceanographic questions for both basic science and Naval applications. The majority of space-borne optical oceanographic parameters observed from CubeSats rely on atmospheric corrections to provide useful data. BeaverCube will both obtain data and help determine to what extent supplemental data will still be required for atmospheric corrections. BeaverCube will make sea surface and cloud top temperature measurements using three cameras: one visible and two FLIR Boson LWIR cameras. In-situ measurements will be coordinated with an array of ocean buoys to support calibration and validation. The student team successfully tested the LWIR camera on a high-altitude balloon launch in November 2019 to an altitude of 110,000 feet, demonstrating the imaging functionality in a near-space environment. The technology goal for BeaverCube is to demonstrate the operation of the Tiled Ionic Liquid Electrospray (TILE2) propulsion technology from Accion Systems, Inc. for orbital maneuvering. BeaverCube will be deployed in Low Earth Orbit from the International Space Station. The plan is to change the altitude of BeaverCube by 480 meters using 50 micro-Newtons of thrust, detected by an onboard GPS receiver. With a goal of launching in late 2020 or early 2021, BeaverCube passed Critical Design Review in Spring 2020, with subsystems designed and procured, including components from AAC Clyde Space (power), ISIS (ADCS), Near Space Launch (BlackBox with GlobalStar simplex radio and NovAtel GPS), and others (OpenLST radio and Raspberry Pi based C&DH board). Assembly and integration prior to environmental testing are planned for late summer 2020

Ticagrelor with or without Aspirin in High-Risk Patients after PCI.

BACKGROUND: Monotherapy with a P2Y12 inhibitor after a minimum period of dual antiplatelet therapy is an emerging approach to reduce the risk of bleeding after percutaneous coronary intervention (PCI). METHODS: In a double-blind trial, we examined the effect of ticagrelor alone as compared with ticagrelor plus aspirin with regard to clinically relevant bleeding among patients who were at high risk for bleeding or an ischemic event and had undergone PCI. After 3 months of treatment with ticagrelor plus aspirin, patients who had not had a major bleeding event or ischemic event continued to take ticagrelor and were randomly assigned to receive aspirin or placebo for 1 year. The primary end point was Bleeding Academic Research Consortium (BARC) type 2, 3, or 5 bleeding. We also evaluated the composite end point of death from any cause, nonfatal myocardial infarction, or nonfatal stroke, using a noninferiority hypothesis with an absolute margin of 1.6 percentage points. RESULTS: We enrolled 9006 patients, and 7119 underwent randomization after 3 months. Between randomization and 1 year, the incidence of the primary end point was 4.0% among patients randomly assigned to receive ticagrelor plus placebo and 7.1% among patients assigned to receive ticagrelor plus aspirin (hazard ratio, 0.56; 95% confidence interval [CI], 0.45 to 0.68; P<0.001). The difference in risk between the groups was similar for BARC type 3 or 5 bleeding (incidence, 1.0% among patients receiving ticagrelor plus placebo and 2.0% among patients receiving ticagrelor plus aspirin; hazard ratio, 0.49; 95% CI, 0.33 to 0.74). The incidence of death from any cause, nonfatal myocardial infarction, or nonfatal stroke was 3.9% in both groups (difference, -0.06 percentage points; 95% CI, -0.97 to 0.84; hazard ratio, 0.99; 95% CI, 0.78 to 1.25; P<0.001 for noninferiority). CONCLUSIONS: Among high-risk patients who underwent PCI and completed 3 months of dual antiplatelet therapy, ticagrelor monotherapy was associated with a lower incidence of clinically relevant bleeding than ticagrelor plus aspirin, with no higher risk of death, myocardial infarction, or stroke. (Funded by AstraZeneca; TWILIGHT ClinicalTrials.gov number, NCT02270242.)

Orbital redistribution in molecular nanostructures mediated by metal-organic bonds

Dicyanovinyl-quinquethiophene (DCV5T-Me) is a prototype conjugated oligomer for highly efficient organic solar cells. This class of oligothiophenes are built up by an electron-rich donor (D) backbone and terminal electron-deficient acceptor (A) moieties. Here, we investigated its structural and electronic properties when it is adsorbed on a Au(111) surface using low temperature scanning tunneling microscopy/spectroscopy (STM/STS) and atomic force microscopy (AFM). We find that DCV5T-Me self-assembles in extended chains, stabilized by intercalated Au atoms. The effect of metal-ligand hybridization with Au adatoms causes an energetic downshift of the DCV5T-Me lowest unoccupied molecular orbital (LUMO) with respect to the uncoordinated molecules on the surface. The asymmetric coordination of a gold atom to only one molecular end group leads to an asymmetric localization of the LUMO and LUMO+1 states at opposite sides. Using model density functional theory (DFT) calculations, we explain such orbital reshaping as a consequence of linear combinations of the original LUMO and LUMO+1 orbitals, mixed by the attachment of a bridging Au adatom. Our study shows that the alignment of molecular orbitals and their distribution within individual molecules can be modified by contacting them to metal atoms in specific sites

Mechanical stability of the CMS strip tracker measured with a laser alignment system

Peer reviewe

Angular analysis of the decay B-0 -> K*(0)mu(+)mu(-) from pp collisions at root s=8 TeV

Peer reviewe

Observation of top quark pairs produced in association with a vector boson in pp collisions at s=8 √s=8TeV

Measurements of the cross sections for top quark pairs produced in association with a W or Z boson are presented, using 8 TeV pp collision data corresponding to an integrated luminosity of 19.5 fb −1 , collected by the CMS experiment at the LHC. Final states are selected in which the associated W boson decays to a charged lepton and a neutrino or the Z boson decays to two charged leptons. Signal events are identified by matching reconstructed objects in the detector to specific final state particles from t t ¯ W tt¯W or t t ¯ Z tt¯Z decays. The t t ¯ W tt¯W cross section is measured to be 382 − 102 + 117 fb with a significance of 4.8 standard deviations from the background-only hypothesis. The t t ¯ Z tt¯Z cross section is measured to be 242 − 55 + 65 fb with a significance of 6.4 standard deviations from the background-only hypothesis. These measurements are used to set bounds on five anomalous dimension-six operators that would affect the t t ¯ W tt¯W and t t ¯ Z tt¯Z cross sections

Search for Resonant Production of High-Mass Photon Pairs in Proton-Proton Collisions at root s=8 and 13 TeV

Peer reviewe

Search for a massive resonance decaying into a Higgs boson and a W or Z boson in hadronic final states in proton-proton collisions at s√=8 TeV

A search for a massive resonance decaying into a standard-model-like Higgs boson (H) and a W or Z boson is reported. The analysis is performed on a data sample corresponding to an integrated luminosity of 19.7 fb$^{-1}$, collected in proton-proton collisions at a centre-of-mass energy of 8TeV with the CMS detector at the LHC. Signal events, in which the decay products of Higgs, W, or Z bosons at high Lorentz boost are contained within single reconstructed jets, are identified using jet substructure techniques, including the tagging of b hadrons. This is the first search for heavy resonances decaying into HW or HZ resulting in an all-jet final state, as well as the first application of jet substructure techniques to identify H → WW* → 4q decays at high Lorentz boost. No significant signal is observed and limits are set at 95% confidence level on the production cross sections of W` and Z` in a model with mass-degenerate charged and neutral spin-1 resonances. Resonance masses are excluded for W0 in the interval [1.0, 1.6]TeV, for Z` in the intervals [1.0, 1.1] and [1.3, 1.5]TeV, and for mass-degenerate W` and Z` in the interval [1.0, 1.7]TeV