742 research outputs found
Unwise or Unconstitutional?: The Copyright Term Extension Act, the Eldred Decision, and the Freezing of the Public Domain for Private Benefit
Rapid TeV Gamma-Ray Flaring of BL Lacertae
We report on the detection of a very rapid TeV gamma-ray flare from BL Lacertae on 2011 June 28 with the Very Energetic Radiation Imaging Telescope Array System (VERITAS). The flaring activity was observed during a 34.6 minute exposure, when the integral flux above 200 GeV reached (3.4 ± 0.6) × 10^(–6) photons m^(–2) s^(–1), roughly 125% of the Crab Nebula flux measured by VERITAS. The light curve indicates that the observations missed the rising phase of the flare but covered a significant portion of the decaying phase. The exponential decay time was determined to be 13 ± 4 minutes, making it one of the most rapid gamma-ray flares seen from a TeV blazar. The gamma-ray spectrum of BL Lacertae during the flare was soft, with a photon index of 3.6 ± 0.4, which is in agreement with the measurement made previously by MAGIC in a lower flaring state. Contemporaneous radio observations of the source with the Very Long Baseline Array revealed the emergence of a new, superluminal component from the core around the time of the TeV gamma-ray flare, accompanied by changes in the optical polarization angle. Changes in flux also appear to have occurred at optical, UV, and GeV gamma-ray wavelengths at the time of the flare, although they are difficult to quantify precisely due to sparse coverage. A strong flare was seen at radio wavelengths roughly four months later, which might be related to the gamma-ray flaring activities. We discuss the implications of these multiwavelength results
Soil Macrofauna as Bioindicator on Aek Loba Palm Oil Plantation Land
Oil palm plantations of PT. Socfin Indonesia (Socfindo) Aek Loba area has been planted with oil palm since 1931, currently has plants from generation I (± 31 years), II (± 47 years), III (± 74 years), and IV (± 86 years) . The difference in the length of time of utilization and management of plantation land in each generation also determines the presence, both species, density, relative density, and the frequency of the presence of soil macrofauna. Soil macrofauna plays a role in maintaining the balance of the soil ecosystem. This research has been conducted at PT. Socfindo Kebun Aek Loba in February 2017- April 2018. This research was conducted to determine the presence of soil macrofauna on oil palm plantation land of PT. Socfin Indonesia (Socfindo) Aek Loba plantation area. Determination of the sampling point is done by the Purposive Random Sampling method, soil macrofauna sampling using the Quadratic and Hand Sorting methods. There are 29 species of soil macrofauna which are grouped into 2 phyla, 3 classes, 11 orders, 21 families, and 27 genera. The highest density value is in the Generation II area of 401.53 ind / m2 and the lowest density value is in the Generation IV area of 101.59 ind / m2. Frequency The presence of soil macrofauna in the four generations consists of 4 species, namely Pontoscolex corethrurus, Geophilus flavus, Vostax apicedentatus, and Solenopsis fugax
Perancangan Visual Brand Identity Dan Promosi Depot Classic Di Surabaya
Depot Classic adalah sebuah depot makanan di Surabaya dengan spesialisasi bahan dasar daging ayam dan mie. Brand Awareness dari Depot Classic masih kurang tinggi, dikarenakan kurang menariknya sisi visual dari identitas yang dimiliki oleh Depot Classic serta belum adanya upaya untuk melakukan kegiatan promosi. Oleh karena itu, Depot Classic memerlukan sebuah identitas visual yang baru dan menarik sekaligus dapat menampilkan karakter dari Depot Classic. Dengan Perancangan Visual Brand Identity dan promosi ini, diharapkan brand awareness dari Depot Classic ini dapat meningkat
Unitarity Restoration in the Presence of Closed Timelike Curves
A proposal is made for a mathematically unambiguous treatment of evolution in
the presence of closed timelike curves. In constrast to other proposals for
handling the naively nonunitary evolution that is often present in such
situations, this proposal is causal, linear in the initial density matrix and
preserves probability. It provides a physically reasonable interpretation of
invertible nonunitary evolution by redefining the final Hilbert space so that
the evolution is unitary or equivalently by removing the nonunitary part of the
evolution operator using a polar decomposition.Comment: LaTeX, 17pp, Revisions: Title change, expanded and clarified
presentation of original proposal, esp. with regard to Heisenberg picture and
remaining in original Hilbert spac
Search for a Correlation Between Very-High-Energy Gamma Rays and Giant Radio Pulses in the Crab Pulsar
We present the results of a joint observational campaign between the Green Bank radio telescope and the VERITAS gamma-ray telescope, which searched for a correlation between the emission of very-high-energy (VHE) gamma rays (E γ \u3e 150 GeV) and giant radio pulses (GRPs) from the Crab pulsar at 8.9 GHz. A total of 15,366 GRPs were recorded during 11.6 hr of simultaneous observations, which were made across four nights in 2008 December and in 2009 November and December. We searched for an enhancement of the pulsed gamma-ray emission within time windows placed around the arrival time of the GRP events. In total, eight different time windows with durations ranging from 0.033 ms to 72 s were positioned at three different locations relative to the GRP to search for enhanced gamma-ray emission which lagged, led, or was concurrent with, the GRP event. Furthermore, we performed separate searches on main pulse GRPs and interpulse GRPs and on the most energetic GRPs in our data sample. No significant enhancement of pulsed VHE emission was found in any of the preformed searches. We set upper limits of 5-10 times the average VHE flux of the Crab pulsar on the flux simultaneous with interpulse GRPs on single-rotation-period timescales. On ~8 s timescales around interpulse GRPs, we set an upper limit of 2-3 times the average VHE flux. Within the framework of recent models for pulsed VHE emission from the Crab pulsar, the expected VHE-GRP emission correlations are below the derived limits
Observation of Markarian 421 in TeV Gamma Rays Over a 14-Year Time Span
The variability of the blazar Markarian 421 in TeV gamma rays over a 14-year time period has been explored with theWhipple 10 m telescope. It is shown that the dynamic range of its flux variations is large and similar to that in X-rays. A correlation between the X-ray and TeV energy bands is observed during some bright flares and when the complete data sets are binned on long timescales. The main database consists of 878.4 hours of observation with theWhipple telescope, spread over 783 nights. The peak energy response of the telescope was 400 GeV with 20% uncertainty. This is the largest database of any TeV-emitting active galactic nucleus (AGN) and hence was used to explore the variability profile of Markarian 421. The time-averaged flux from Markarian 421 over this period was 0.446+/-0.008 Crab flux units. The flux exceeded 10 Crab flux units on three separate occasions. For the 2000-2001 season the average flux reached 1.86 Crab units, while in the 1996-1997 season the average flux was only 0.23 Crab units
Quantum Backreaction on ``Classical'' Variables
A mathematically consistent procedure for coupling quasiclassical and quantum
variables through coupled Hamilton-Heisenberg equations of motion is derived
from a variational principle. During evolution, the quasiclassical variables
become entangled with the quantum variables with the result that the value of
the quasiclassical variables depends on the quantum state. This provides a
formalism to compute the backreaction of any quantum system on a quasiclassical
one. In particular, it leads to a natural candidate for a theory of gravity
coupled to quantized matter in which the gravitational field is not quantized.Comment: LaTeX, 10 pp. title change, minor improvement of presentatio
Make Better Choices (MBC): Study design of a randomized controlled trial testing optimal technology-supported change in multiple diet and physical activity risk behaviors
<p>Abstract</p> <p>Background</p> <p>Suboptimal diet and physical inactivity are prevalent, co-occurring chronic disease risk factors, yet little is known about how to maximize multiple risk behavior change. Make Better Choices, a randomized controlled trial, tests competing hypotheses about the optimal way to promote healthy change in four bundled risk behaviors: high saturated fat intake, low fruit and vegetable intake, low physical activity, and high sedentary leisure screen time. The study aim is to determine which combination of two behavior change goals - one dietary, one activity - yields greatest overall healthy lifestyle change.</p> <p>Methods/Design</p> <p>Adults (n = 200) with poor quality diet and sedentary lifestyle will be recruited and screened for study eligibility. Participants will be trained to record their diet and activities onto a personal data assistant, and use it to complete two weeks of baseline. Those who continue to show all four risk behaviors after baseline recording will be randomized to one of four behavior change prescriptions: 1) increase fruits and vegetables and increase physical activity, 2) decrease saturated fat and increase physical activity, 3) increase fruits and vegetable and decrease saturated fat, or 4) decrease saturated fat and decrease sedentary activity. They will use decision support feedback on the personal digital assistant and receive counseling from a coach to alter their diet and activity during a 3-week prescription period when payment is contingent upon meeting behavior change goals. They will continue recording on an intermittent schedule during a 4.5-month maintenance period when payment is not contingent upon goal attainment. The primary outcome is overall healthy lifestyle change, aggregated across all four risk behaviors.</p> <p>Discussion</p> <p>The Make Better Choices trial tests a disseminable lifestyle intervention supported by handheld technology. Findings will fill a gap in knowledge about optimal goal prescription to facilitate simultaneous diet and activity change. Results will shed light on which goal prescription maximizes healthful lifestyle change.</p> <p>Trial Registration</p> <p>Clinical Trials Gov. Identifier NCT00113672</p
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