254 research outputs found
Introducing the black hole
The quasi-stellar object, the pulsar, the neutron star have all come onto the scene of physics within the space of a few years. Is the next entrant destined to be the black hole? If so, it is difficult to think of any development that could be of greater significance. A black hole, whether of âordinary sizeâ (approximately one solar mass, 1 Mâ) or much larger (around 10^6 Mâ to 10^10 Mâ, as proposed in the nuclei of some galaxies), provides our âlaboratory modelâ for the gravitational collapse, predicted by Einstein's theory, of the universe itself
âen pathosâ
`en pathos ` A Greek term that translates to ` in passion ` . The human figure is a timeless and classic subject that has always bestirred feelings of passion in the hearts of both artist and viewer. It can easily take a lifetime\u27s artistic endeavors to master just a tiny aspect of the figure\u27s potential. More important than the literal realm of the figure, there also lies a subjective realm, a place where my work is created and lives.....a place `between\u27. In trying to capture the essence of the human figure, each artistic medium offers its own unique visual interpretation, be it with paint, ink, charcoal, clay, metal or wood. My philosophy as a visual artist is to welcome risk and chance, and to nourish interest into passion.....for the true artist\u27s work is most certainly created.....\u27en pathos\u27
Enabling III-V-based optoelectronics with low-cost dynamic hydride vapor phase epitaxy
Silicon is the dominant semiconductor in many semiconductor device
applications for a variety of reasons, including both performance and cost.
III-V materials have improved performance compared to silicon, but currently
they are relegated to applications in high-value or niche markets due to the
absence of a low-cost, high-quality production technique. Here we present an
advance in III-V materials synthesis using hydride vapor phase epitaxy that has
the potential to lower III-V semiconductor deposition costs by orders of
magnitude while maintaining the requisite optoelectronic material quality that
enables III-V-based technologies to outperform Si. We demonstrate the impacts
of this advance by addressing the use of III-Vs in terrestrial photovoltaics, a
highly cost-constrained market. The emergence of a low-cost III-V deposition
technique will enable III-V electronic and opto-electronic devices, with all
the benefits that they bring, to permeate throughout modern society.Comment: pre-prin
Spherical light, arbitrary nonparaxial accelerating beams and femtosecond laser micromachining of curved profiles
International audienceWe review our recent results applying caustics wave theory to the generation of arbitrary curved accelerating beams and their use in the field of femtosecond laser materials processing. We report experimental realization of highly nonparaxial accelerating beams with circular, parabolic and quartic trajectories that extend over more than 95 degrees of arc as well as spherical optical fields. We also report femtosecond laser curved edge profiling
Persistence of treatment in patients with ulcerative colitis who responded to tofacitinib therapy: data from the open-label, long-term extension study, OCTAVE open
Tofacitinib is an oral Janus kinase inhibitor for the treatment of ulcerative colitis (UC).
Aim:This post hoc analysis evaluated tofacitinib persistence in patients with UC in OCTAVE Open, an open-label, long-term extension study of patients receiving tofacitinib 5 or 10Â mg twice daily.
Methods: Kaplan-Meier estimates for tofacitinib drug survival and reasons for discontinuations were evaluated. Baseline factors were analysed as predictors of persistence.
Results:This analysis included 603 patients: 280 entered OCTAVE Open with a clinical response (164 in remission and 116 not in remission), 220 were delayed responders, 75 were retreatment responders and 35 were dose escalation responders, treated for up to 7Â years in OCTAVE Open. Of these, 118 (42.1%) responders, 121 (55.0%) delayed responders, 40 (53.3%) retreatment responders and 17 (48.6%) dose escalation responders discontinued tofacitinib with a median time to discontinuation of 5.6, 4.5, 4.0 and 4.4Â years, respectively. The estimated 2- and 5-year drug survival rates in the responders (including patients in remission and not in remission) were 73.9% and 54.5%, respectively. Corresponding persistence values for delayed responders were 69.5% and 45.2%, for retreatment responders, 70.7% and 40.0%, and for dose escalation responders, 74.3% and 32.8%.
ConclusionIn: OCTAVE Open, a high proportion of patients maintained tofacitinib treatment, with the median survival by group ranging from 4.0 to 5.6Â years although these analyses are post hoc and limited by sample size. Further research should focus on factors to enhance persistence with tofacitinib treatment in patients with UCThis study was sponsored by Pfizer. Medical writing support, under the guidance of the authors, was provided by Helen Findlow, PhD, CMC Connect, McCann Health Medical Communications and was funded by Pfizer Inc, New York, NY, USA in accordance with Good Publication Practice (GPP3) guidelines (Ann Intern Med. 2015;163:461â464
The eSMA: description and first results
The eSMA ("extended SMA") combines the SMA, JCMT and CSO into a single
facility, providing enhanced sensitivity and spatial resolution owing to the
increased collecting area at the longest baselines. Until ALMA early science
observing (2011), the eSMA will be the facility capable of the highest angular
resolution observations at 345 GHz. The gain in sensitivity and resolution will
bring new insights in a variety of fields, such as protoplanetary/transition
disks, high-mass star formation, solar system bodies, nearby and high-z
galaxies. Therefore the eSMA is an important facility to prepare the grounds
for ALMA and train scientists in the techniques.
Over the last two years, and especially since November 2006, there has been
substantial progress toward making the eSMA into a working interferometer. In
particular, (i) new 345-GHz receivers, that match the capabilities of the SMA
system, were installed at the JCMT and CSO; (ii) numerous tests have been
performed for receiver, correlator and baseline calibrations in order to
determine and take into account the effects arising from the differences
between the three types of antennas; (iii) first fringes at 345 GHz were
obtained on August 30 2007, and the array has entered the science-verification
stage.
We report on the characteristics of the eSMA and its measured performance at
230 GHz and that expected at 345 GHz. We also present the results of the
commissioning and some initial science-verification observations, including the
first absorption measurement of the C/CO ratio in a galaxy at z=0.89, located
along the line of sight to the lensed quasar PKS1830-211, and on the imaging of
the vibrationally excited HCN line towards IRC+10216.Comment: 12 pages, 7 figures, paper number 7012-12, to appear in Proceedings
of SPIE vol. 7012: "Ground-based and Airborne Telescopes II", SPIE conference
on Astronomical Instrumentation, Marseille, 23-28 June 200
Filamentation of high-angle nondiffracting beams and applications to ultrafast laser processing
International audienceWe report on filamentation of nondiffracting beams and show that the intense light-matter interaction regime achieved on long distances allows for an enhanced control on ultrashort laser deep ablation
High precision differential abundance measurements in globular clusters: Chemical inhomogeneities in NGC 6752
We report on a strictly differential line-by-line analysis of high-quality UVES spectra of bright giants in the metal-poor globular cluster NGC 6752. We achieved high precision differential chemical abundance measurements for Fe, Na, Si, Ca, Ti, Cr, Ni,
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