284 research outputs found
Measurement of the cosmic microwave background polarization lensing power spectrum from two years of POLARBEAR data
We present a measurement of the gravitational lensing deflection power spectrum reconstructed with two seasons of cosmic microwave background polarization data from the POLARBEAR experiment. Observations were taken at 150 GHz from 2012 to 2014 and surveyed three patches of sky totaling 30 square degrees. We test the consistency of the lensing spectrum with a cold dark matter cosmology and reject the no-lensing hypothesis at a confidence of 10.9Ï, including statistical and systematic uncertainties. We observe a value of AL = 1.33 ± 0.32 (statistical) ±0.02 (systematic) ±0.07 (foreground) using all polarization lensing estimators, which corresponds to a 24% accurate measurement of the lensing amplitude. Compared to the analysis of the first- year data, we have improved the breadth of both the suite of null tests and the error terms included in the estimation of systematic contamination
Internal delensing of cosmic microwave background polarization B-Modes with the POLARBEAR experiment
International audienceUsing only cosmic microwave background polarization data from the polarbear experiment, we measure B-mode polarization delensing on subdegree scales at more than 5Ï significance. We achieve a 14% B-mode power variance reduction, the highest to date for internal delensing, and improve this result to 22% by applying for the first time an iterative maximum a posteriori delensing method. Our analysis demonstrates the capability of internal delensing as a means of improving constraints on inflationary models, paving the way for the optimal analysis of next-generation primordial B-mode experiments
Voluntary organizations and societyâmilitary relations in contemporary Russia
The 2014 crisis in Ukraine has refocused attention on Russia as a European security actor. Despite showing renewed military capability, compared to the post-Soviet period, Russian societyâmilitary relations have remained the same. This relationship (between society and the security organs) provides the key context for assessing security. Analysis of everyday militarization and the role of voluntary organizations (such as DOSAAF [Dobrovol'noe obshchestvo sodeistviya armii, aviatsii i flotu] and Nashi [Molodezhnoe demokraticheskoe antifashistskoe dvizheni]) in supporting the military can provide an important insight into Russian behaviour as a security actor. These organizations generate a pro-military outlook and at the same time provide training and activities, thus contributing to military effectiveness by developing the competency of young people prior to military service as well as increasing public knowledge of military affairs. However, strong support for the military, a lack of independent information, and an absence of a shared vision on how societyâmilitary relations should be developed and also represent political challenges in terms of everyday militarization. This dynamic is important for understanding both Russia's security posture and wider security implications for Europe
Measurements of tropospheric ice clouds with a ground-based CMB polarization experiment, POLARBEAR
The polarization of the atmosphere has been a long-standing concern for ground-based experiments targeting cosmic microwave background (CMB) polarization. Ice crystals in upper tropospheric clouds scatter thermal radiation from the ground and produce a horizontally polarized signal. We report a detailed analysis of the cloud signal using a ground-based CMB experiment, Polarbear, located at the Atacama desert in Chile and observing at 150 GHz. We observe horizontally polarized temporal increases of low-frequency fluctuations ("polarized bursts," hereafter) of 720.1 K when clouds appear in a webcam monitoring the telescope and the sky. The hypothesis of no correlation between polarized bursts and clouds is rejected with >24\u3c3 statistical significance using three years of data. We consider many other possibilities including instrumental and environmental effects, and find no reasons other than clouds that can explain the data better. We also discuss the impact of the cloud polarization on future ground-based CMB polarization experiments
Targeting transcription regulation in cancer with a covalent CDK7 inhibitor
Tumour oncogenes include transcription factors that co-opt the general transcriptional machinery to sustain the oncogenic state, but direct pharmacological inhibition of transcription factors has so far proven difficult. However, the transcriptional machinery contains various enzymatic cofactors that can be targeted for the development of new therapeutic candidates, including cyclin-dependent kinases (CDKs). Here we present the discovery and characterization of a covalent CDK7 inhibitor, THZ1, which has the unprecedented ability to target a remote cysteine residue located outside of the canonical kinase domain, providing an unanticipated means of achieving selectivity for CDK7. Cancer cell-line profiling indicates that a subset of cancer cell lines, including human T-cell acute lymphoblastic leukaemia (T-ALL), have exceptional sensitivity to THZ1. Genome-wide analysis in Jurkat T-ALL cells shows that THZ1 disproportionally affects transcription of RUNX1 and suggests that sensitivity to THZ1 may be due to vulnerability conferred by the RUNX1 super-enhancer and the key role of RUNX1 in the core transcriptional regulatory circuitry of these tumour cells. Pharmacological modulation of CDK7 kinase activity may thus provide an approach to identify and treat tumour types that are dependent on transcription for maintenance of the oncogenic state.National Institutes of Health (U.S.) (Grant HG002668)National Institutes of Health (U.S.) (Grant CA109901
The changing role of china in the global illegal cigarette trade
This study explores the history of the illegal production, distribution, and smuggling of cigarettes in mainland China. Data were obtained from a content analysis of 931 media reports retrieved from LexisNexis for the time period 1975 until 2010, and from other open sources. The illegal cigarette trade first emerged in the form of violations of state tobacco monopoly regulations. In the course of the restructuring of the legal tobacco sector, which occurred under external political pressure to open the Chinese market to foreign competition, an illegal cigarette industry emerged which at first primarily produced fake Chinese brand cigarettes for the domestic black market. At the same time, China became a destination country for smuggled genuine Western brand cigarettes. It was only after effective crackdowns against cigarette smuggling and domestic distribution channels in the late 1990s that the Chinese illegal cigarette industry shifted to exporting large numbers of counterfeit Western brand cigarettes to black markets abroad. Chinaâs current role as a leading supplier of counterfeit cigarettes is a result of the contradictions of the economic reform process and of external licit and illicit forces that worked toward opening up the Chinese tobacco sector to the outside world
High power Q-switched thulium doped fibre laser using carbon nanotube polymer composite saturable absorber
We have proposed and demonstrated a Q-switched Thulium doped bre laser (TDFL) with a âYin-Yangâ all- bre cavity scheme based on a combination of nonlinear optical loop mirror (NOLM) and nonlinear ampli ed loop mirror (NALM). Unidirectional lasing operation has been achieved without any intracavity isolator. By using a carbon nanotube polymer composite based saturable absorber (SA), we demonstrated the laser output power of ~197 mW and pulse energy of 1.7 ÎŒJ. To the best of our knowledge, this is the highest output power from a nanotube polymer composite SA based Q-switched Thulium doped bre laser
Cross-correlation of CMB polarization lensing with High-z submillimeter Herschel-ATLAS galaxies
We report a 4.8Ï measurement of the cross-correlation signal between the cosmic microwave background (CMB) lensing convergence reconstructed from measurements of the CMB polarization made by the Polarbear experiment and the infrared-selected galaxies of the Herschel-ATLAS survey. This is the first measurement of its kind
The POLARBEAR-2 and Simons Array Focal Plane Fabrication Status
We present on the status of POLARBEAR-2 A (PB2-A) focal plane fabrication.
The PB2-A is the first of three telescopes in the Simon Array (SA), which is an
array of three cosmic microwave background (CMB) polarization sensitive
telescopes located at the POLARBEAR (PB) site in Northern Chile. As the
successor to the PB experiment, each telescope and receiver combination is
named as PB2-A, PB2-B, and PB2-C. PB2-A and -B will have nearly identical
receivers operating at 90 and 150 GHz while PB2-C will house a receiver
operating at 220 and 270 GHz. Each receiver contains a focal plane consisting
of seven close-hex packed lenslet coupled sinuous antenna transition edge
sensor bolometer arrays. Each array contains 271 di-chroic optical pixels each
of which have four TES bolometers for a total of 7588 detectors per receiver.
We have produced a set of two types of candidate arrays for PB2-A. The first we
call Version 11 (V11) and uses a silicon oxide (SiOx) for the transmission
lines and cross-over process for orthogonal polarizations. The second we call
Version 13 (V13) and uses silicon nitride (SiNx) for the transmission lines and
cross-under process for orthogonal polarizations. We have produced enough of
each type of array to fully populate the focal plane of the PB2-A receiver. The
average wirebond yield for V11 and V13 arrays is 93.2% and 95.6% respectively.
The V11 arrays had a superconducting transition temperature (Tc) of 452 +/- 15
mK, a normal resistance (Rn) of 1.25 +/- 0.20 Ohms, and saturations powers of
5.2 +/- 1.0 pW and 13 +/- 1.2 pW for the 90 and 150 GHz bands respectively. The
V13 arrays had a superconducting transition temperature (Tc) of 456 +/-6 mK, a
normal resistance (Rn) of 1.1 +/- 0.2 Ohms, and saturations powers of 10.8 +/-
1.8 pW and 22.9 +/- 2.6 pW for the 90 and 150 GHz bands respectively
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