2,429 research outputs found
How to Commission, Operate and Maintain a Large Future Accelerator Complex from Far Remote
A study on future large accelerators [1] has considered a facility, which is
designed, built and operated by a worldwide collaboration of equal partner
institutions, and which is remote from most of these institutions. The full
range of operation was considered including commi-ssioning, machine
development, maintenance, trouble shooting and repair. Experience from existing
accele-rators confirms that most of these activities are already performed
'remotely'. The large high-energy physics ex-periments and astronomy projects,
already involve inter-national collaborations of distant institutions. Based on
this experience, the prospects for a machine operated remotely from far sites
are encouraging. Experts from each laboratory would remain at their home
institution but continue to participate in the operation of the machine after
construction. Experts are required to be on site only during initial
commissioning and for par-ticularly difficult problems. Repairs require an
on-site non-expert maintenance crew. Most of the interventions can be made
without an expert and many of the rest resolved with remote assistance. There
appears to be no technical obstacle to controlling an accelerator from a
distance. The major challenge is to solve the complex management and
communication problems.Comment: ICALEPCS 2001 abstract ID No. FRBI001 invited talk submitting author
F. Willeke 5 pages, 1 figur
Quasipolyhedral sets in linear semiinfinite inequality systems
AbstractThis paper provides an extension to linear semiinfinite systems of a well-known property of finite linear inequality systems, the so-called Weyl property, which characterizes the extreme points of the solution set as those solution points such that the gradient vectors of the active constraints form a complete set. A class of linear semiinfinite systems which satisfy this property is identified, the p-systems. It is also shown that any p-system contains an equivalent minimal subsystem
Fast Time Structure During Transient Microwave Brightenings: Evidence for Nonthermal Processes
Transient microwave brightenings (TMBs) are small-scale energy releases from
the periphery of sunspot umbrae, with a flux density two orders of magnitude
smaller than that from a typical flare. Gopalswamy et al (1994) first reported
the detection of the TMBs and it was pointed out that the radio emission
implied a region of very high magnetic field so that the emission mechanism has
to be gyroresonance or nonthermal gyrosynchrotron, but not free-free emission.
It was not possible to decide between gyroresonance and gyrosynchrotron
processes because of the low time resolution (30 s) used in the data analysis.
We have since performed a detailed analysis of the Very Large Array data with
full time resolution (3.3 s) at two wavelengths (2 and 3.6 cm) and we can now
adequately address the question of the emission mechanism of the TMBs. We find
that nonthermal processes indeed take place during the TMBs. We present
evidence for nonthermal emission in the form of temporal and spatial structure
of the TMBs. The fast time structure cannot be explained by a thermodynamic
cooling time and therefore requires a nonthermal process. Using the physical
parameters obtained from X-ray and radio observations, we determine the
magnetic field parameters of the loop and estimate the energy released during
the TMBs. The impulsive components of TMBs imply an energy release rate of 1.3
x 10^22 erg/s so that the thermal energy content of the TMBs could be less than
10^24 erg.Comment: 15 pages (Latex), 4 figures (eps). ApJ Letters in press (1997
Stability of the Duality Gap in Linear Optimization
In this paper we consider the duality gap function g that measures the difference between the optimal values of the primal problem and of the dual problem in linear programming and in linear semi-infinite programming. We analyze its behavior when the data defining these problems may be perturbed, considering seven different scenarios. In particular we find some stability results by proving that, under mild conditions, either the duality gap of the perturbed problems is zero or + ∞ around the given data, or g has an infinite jump at it. We also give conditions guaranteeing that those data providing a finite duality gap are limits of sequences of data providing zero duality gap for sufficiently small perturbations, which is a generic result.This research was partially supported by MINECO of Spain and FEDER of EU, Grant MTM2014-59179-C2-01 and SECTyP-UNCuyo Res. 4540/13-R
Selected Applications of Linear Semi-Infinite Systems Theory
In this paper we, firstly, review the main known results on systems of an arbitrary (possibly infinite) number of weak linear inequalities posed in the Euclidean space Rn (i.e., with n unknowns), and, secondly, show the potential power of this theoretical tool by developing in detail two significant applications, one to computational geometry: the Voronoi cells, and the other to mathematical analysis: approximate subdifferentials, recovering known results in both fields and proving new ones. In particular, this paper completes the existing theory of farthest Voronoi cells of infinite sets of sites by appealing to well-known results on linear semi-infinite systems.This research was partially supported by PGC2018-097960-B-C22 of the Ministerio de Ciencia, Innovación y Universidades (MCIU), the Agencia Estatal de Investigación (AEI), and the European Regional Development Fund (ERDF); by CONICET, Argentina, Res D No 4198/17; and by Universidad Nacional de Cuyo, SecretarÃa de Investigación, Internacionales y Posgrado (SIIP), Res. 3922/19-R, Cod.06/D227, Argentina
The Voronoi inverse mapping
Given an arbitrary set T in the Euclidean space whose elements are called sites, and a particular site s, the Voronoi cell of s , denoted by VT(s)VT(s), consists of all points closer to s than to any other site. The Voronoi mapping of s , denoted by ψsψs, associates to each set T∋sT∋s the Voronoi cell VT(s)VT(s) of s w.r.t. T . These Voronoi cells are solution sets of linear inequality systems, so they are closed convex sets. In this paper we study the Voronoi inverse problem consisting in computing, for a given closed convex set F∋sF∋s, the family of sets T∋sT∋s such that ψs(T)=Fψs(T)=F. More in detail, the paper analyzes relationships between the elements of this family, ψs−1(F), and the linear representations of F , provides explicit formulas for maximal and minimal elements of ψs−1(F), and studies the closure operator that assigns, to each closed set T containing s , the largest element of ψs−1(F), where F=VT(s)F=VT(s).This work has been supported by MINECO of Spain and ERDF from EC, Grants MTM2011-29064-C03-01, MTM2011-29064-C03-02, Australian Research Council’s Discovery Projects funding scheme (project number DP140103213), Severo Ochoa Programme for Centres of Excellence in R&D (SEV-2015-0563), and SECTyP-UNCuyo, Argentina, Grant Res. 4540/13-R. The second author is affiliated to MOVE (Markets, Organizations and Votes in Economics)
Survey of Low Birthweight and Extremely Low Birthweight Events in a High Environmental Risk Area of Apulia, Italy
The association between environmental conditions and pregnancy outcome has been under investigation for a long time, but results appear to be inconclusive regarding damage to either the newborn or the mother. The aim of this study was to evaluate the distribution of hospitalization of newborns with low birthweight (< 2500 g) and extremely low birthweight (< 1000 g) in the geographical area of Taranto, Italy, which is characterized by high environmental risk because of industrial pollution. We analyzed the database of hospital discharge forms for the years 2001–2013 regarding hospital admission of newborns in the region of Apulia. The relative risk (RR) of hospitalization, adjusted for the deprivation index, was estimated using the Besag–York–Molliè Bayesian model. The city of Taranto, which has the highest environmental risk, had the highest RR for newborns with low birthweight (1.47, 95% uncertainty interval 1.38–1.56). Other geographical areas with high environmental pollution had higher RRs for low birth weight compared with the regional average. We found no geographical distribution pattern of extremely low birthweight that would suggest an association with environmental pollution
Changes in the Phytochemical Profile and Antioxidant Properties of Prunus persica Fruits after the Application of a Commercial Biostimulant Based on Seaweed and Yeast Extract
Plant biostimulants are formulations that are experiencing great success from the perspective of sustainable agriculture. In this work, we evaluated the effect derived from the application of a biostimulant based on algae and yeast extracts (Expando (R)) on the agronomic yield and nutraceutical profile of two different cultivars ("Sugar Time" and "West Rose") of Prunus persica (peach). Although, at the agronomic level, significant effects on production yields were not recorded, the biostimulant was able to reduce the ripening time, increase the fruit size, and make the number of harvestable fruits homogeneous. From a nutraceutical point of view, our determinations via spectrophotometric (UV/Vis) and chromatographic (HPLC-DAD-MS/MS) analysis showed that the biostimulant was able to boost the content of bioactive compounds in both the pulp (5.0 L/ha: +17%; 4.0 L/ha: +12%; 2.5 L/ha: +11%) and skin (4.0 L/ha: +38%; 2.5 L/ha: +15%). These changes seem to follow a dose-dependent effect, also producing attractive effects on the antioxidant properties of the fruits harvested from the treated trees. In conclusion, the biostimulant investigated in this work proved to be able to produce more marketable fruit in a shorter time, both from a pomological and a functional point of view
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