16,221 research outputs found
Corrigendum to "Knot Floer homology detects fibred knots"
We correct a mistake on the citation of JSJ theory in \cite{Ni}. Some
arguments in \cite{Ni} are also slightly modified accordingly.Comment: 3 page
An extensible product structure model for product lifecycle management in the make-to-order environment
This paper presents a product structure model with a semantic representation technique that make the product structure extensible for developing product lifecycle management (PLM) systems that is flexible for make-to-order environment. In the make-to-order business context, each product could have a number of variants with slightly different constitutions to fulfill different customer requirements. All the variants of a family have common characteristics and each variant has its specific features. A master-variant pattern is proposed for building the product structure model to explicitly represent common characteristics and specific features of individual variants. The model is capable of enforcing the consistency of a family structure and its variant structure, supporting multiple product views, and facilitating the business processes. A semantic representation technique is developed that enables entity attributes to be defined and entities to be categorized in a neutral and semantic format. As a result, entity attributes and entity categorization can be redefined easily with its configurable capability for different requirements of the PLM systems. An XML-based language is developed for semantically representing entities and entity categories. A prototype as a proof-of-concept system is presented to illustrate the capability of the proposed extensible product structure model
The effect of the motion of the Sun on the light-time in interplanetary relativistic experiments
In 2002 a measurement of the effect of solar gravity upon the phase of
coherent microwave beams passing near the Sun has been carried out with the
Cassini mission, allowing a very accurate measurement of the PPN parameter
. The data have been analyzed with NASA's Orbit Determination Program
(ODP) in the Barycentric Celestial Reference System, in which the Sun moves
around the centre of mass of the solar system with a velocity of
about 10 m/sec; the question arises, what correction this implies for the
predicted phase shift. After a review of the way the ODP works, we set the
problem in the framework of Lorentz (and Galilean) transformations and evaluate
the correction; it is several orders of magnitude below our experimental
accuracy. We also discuss a recent paper \cite{kopeikin07}, which claims wrong
and much larger corrections, and clarify the reasons for the discrepancy.Comment: Final version accepted by Classical and Quantum Gravity (8 Jan. 2008
Protective Effect of Lemon (Citrus Limon L.) Ethanol Extract Cream as an Antioxidant Against Exposure to Ultraviolet B Rays in the Skin of Male Wistar (Rattus Norvegicus) Rats
Background: Indonesia is an archipelagic country and one of the tropical countries that get sun exposure all the time. Sun exposure can have beneficial and detrimental effects in life. Exposure to radiation can cause acute effects in the form of erythema through the inflammatory process. Antioxidants are substances that can protect the body from damage caused by ROS. Natural antioxidants can be found in vegetables and fruits, one of which comes from lemon extract (Citrus limon L.). Lemon extract is known to have various chemical contents with active compounds in the form of flavonoids and phenols which can act as antioxidants. The aim of this research was to determine the protective effect that can be produced by lemons on UVB exposure in the skin of male wistar rats.Methods: This research uses the true experimental post test only control group design method. Samples were divided into three treatment concentrations, namely ethanol extract of lemon 5%, 10%, and 20%.Result: After testing for normality, the significance value was obtained (p <0.05). Based on the results of the normality and homogeneity test, the results of the data distribution are not normal and the homogeneous tests of the hypotheses used are the Kruskal-Wallis non-parametric test. Kruskal-Wallis non-parametric test results showed a significant difference with the significance value (p = 0.001). The best degree of erythema score was found in the cream of 10% ethanol extract of lemon with an average of 0.8 ± 0.84.Conclusion : The ethanol extract of lemon (Citrus limon L.) cream in a certain dosage has a significant effect on reducing the erythema degree score in the back skin of male Wistar rats (Rattus norvegicus) after exposure to UVB rays
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Experimental and Theoretical Studies of the Environmental Sensitivity of the Absorption Spectra and Photochemistry of Nitenpyram and Analogs
Neonicotinoid (NN) pesticides have widespread use, largely replacing other pesticides such as the carbamates. Hence, there is a need to understand their environmental fates at a molecular level in various media, especially water. We report here the studies of a nitroenamine NN, nitenpyram (NPM), in aqueous solution where the absorption cross sections in the actinic region above 290 nm are observed to dramatically decrease compared to those in nonaqueous solvents. Quantum chemical calculations show that addition of a proton to the tertiary amine nitrogen in NPM breaks the conjugation in the chromophore, shifting the absorption to shorter wavelengths, consistent with experiment. However, surprisingly, adding a proton to the secondary amine nitrogen leads to its immediate transfer to the NO2 group, preserving the conjugation. This explains why the UV absorption of ranitidine (RAN), which has a similar chromophore but only secondary amine nitrogens, does not show a similar large blue shift in water. Photolysis quantum yields in aqueous NPM solutions were measured to be φ = 0.18 ± 0.07 at 254 nm, (9.4 ± 1.6) × 10-2 with broadband radiation centered at 313 nm and (5.2 ± 1.1) × 10-2 for broadband radiation centered at 350 nm (errors are 2σ). The major products in aqueous solutions are an imine that was also formed in the photolysis of the solid and a carboxylic acid derivative that is unique to the photolysis in water. Combining the larger quantum yields in water with the reduced absorption cross sections results in a calculated lifetime of NPM of only 5 min at a solar zenith angle of 35°, typical of 40°N latitude on April 1. The products do not absorb in the actinic region and hence will be long-lived with respect to photolysis
A New Test of the Einstein Equivalence Principle and the Isotropy of Space
Recent research has established that nonsymmetric gravitation theories like
Moffat's NGT predict that a gravitational field singles out an orthogonal pair
of polarization states of light that propagate with different phase velocities.
We show that a much wider class of nonmetric theories encompassed by the formalism predict such violations of the Einstein equivalence principle.
This gravity-induced birefringence of space implies that propagation through a
gravitational field can alter the polarization of light. We use data from
polarization measurements of extragalactic sources to constrain birefringence
induced by the field of the Galaxy. Our new constraint is times sharper
than previous ones.Comment: 21 pages, Latex, 3 Postscript figure
Ellipsometry noise spectrum, suspension transfer function measurement and closed-loop control of the suspension system in the Q & A experiment
The Q & A experiment, aiming at the detection of vacuum birefringence
predicted by quantum electrodynamics, consists mainly of a suspended 3.5 m
Fabry-Perot cavity, a rotating permanent dipole magnet and an ellipsometer. The
2.3 T magnet can rotate up to 10 rev/s, introducing an ellipticity signal at
twice the rotation frequency. The X-pendulum gives a good isolation ratio for
seismic noise above its main resonant frequency 0.3 Hz. At present, the
ellipsometry noise decreases with frequency, from 1*10^{-5} rad Hz^{-1/2} at 5
Hz, 2*10^{-6} rad Hz^{-1/2} at 20 Hz to 5*10^{-7} rad Hz^{-1/2} at 40 Hz. The
shape of the noise spectrum indicates possible improvement can be made by
further reducing the movement between the cavity mirrors. From the preliminary
result of yaw motion alignment control, it can be seen that some peaks due to
yaw motion of the cavity mirror was suppressed. In this paper, we first give a
schematic view of the Q & A experiment, and then present the measurement of
transfer function of the compound X-pendulum-double pendulum suspension. A
closed-loop control was carried out to verify the validity of the measured
transfer functions. The ellipsometry noise spectra with and without yaw
alignment control and the newest improvement is presented.Comment: 7 pages, 5 figures, presented in 6th Edoardo Amaldi Conference on
Gravitational Waves, June 2005, Okinawa Japan and submitted to Journal of
Physics: Conference Series. Some modifications are made according to the
referee's comments: mainly to explain the relation between the displacement
of cavity mirror and the ellipticity noise spectru
Non-profit organizations as a nexus between government and business in an emerging market: Evidence from Chinese charities
Research summary
Non-profit organizations in emerging markets frequently have to manage relations with governments and for-profit firms. We advance a multi-stakeholder perspective and develop propositions about how the political ties of charities influence their success in raising funds from corporate donors. Evidence from 2,054 Chinese charities during 2005-2012 shows that organizational political ties, established through formal affiliation with the government, aid fundraising from corporate donors, whereas personal political ties, formed through personal political services of senior leaders of charities, have no such effect. The positive effect of government affiliation is relevant for both foreign and domestic donors, but stronger for domestic ones. These results highlight the differential impact and contingent value of political embeddedness for charities’ ability to acquire resources from for-profit business, contributing to both stakeholder theory and the political embeddedness perspective.
Managerial summary
Non-profit organizations have to maintain productive relations with multiple stakeholders, including government and business. We focus on Chinese charities that seek to raise funds to fulfill their mission. We identify how their political relations influence the behavior of corporate donors. Evidence from 2,054 charities from 2005-2012 shows that political ties formed through organizational affiliation with a political body help charities attract corporate donors that seek legitimacy. In contrast, ties formed through personal connections with politicians have less influence on donors who perceive a high risk of connected insiders engaging in activities of dubious legality. The value of political ties is more pronounced for domestic corporate donors
Numerical simulation of time delay interferometry for eLISA/NGO
eLISA/NGO is a new gravitational wave detection proposal with arm length of
10^6 km and one interferometer down-scaled from LISA. Just like LISA and
ASTROD-GW, in order to attain the requisite sensitivity for eLISA/NGO, laser
frequency noise must be suppressed to below the secondary noises such as the
optical path noise, acceleration noise etc. In previous papers, we have
performed the numerical simulation of the time delay interferometry (TDI) for
LISA and ASTROD-GW with one arm dysfunctional by using the CGC 2.7 ephemeris.
The results are well below their respective limits which the laser frequency
noise is required to be suppressed. In this paper, we follow the same procedure
to simulate the time delay interferometry numerically. To do this, we work out
a set of 1000-day optimized mission orbits of the eLISA/NGO spacecraft starting
at January 1st, 2021 using the CGC 2.7 ephemeris framework. We then use the
numerical method to calculate the residual optical path differences in the
second-generation TDI solutions as in our previous papers. The maximum path
length difference, for all configurations calculated, is below 13 mm (43 ps).
It is well below the limit which the laser frequency noise is required to be
suppressed for eLISA/NGO. We compare and discuss the resulting differences due
to the different arm lengths for various mission proposals -- eLISA/NGO, an
NGO-LISA-type mission with a nominal arm length of 2 x 10^6 km, LISA and
ASTROD-GW.Comment: 17 pages, 13 figures, 3 tables, minor changes in description to match
the accepted version of Classical and Quantum Gravity. arXiv admin note: text
overlap with arXiv:1102.496
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