378 research outputs found
Purely twistorial string with canonical twistor field quantization
We introduce new purely twistorial scale-invariant action describing the
composite bosonic D=4 Nambu-Goto string with target space parametrized by the
pair of D=4 twistors. We show that by suitable gauge fixing of local scaling
one gets the bilinear twistorial action and canonical quantization rules for
the two-dimensional twistor-string fields. We consider the Poisson brackets of
all constraints characterizing our model and we obtain four first class
constraints describing two Virasoro constraints and two U(1)xU(1) Kac-Moody
(KM) local phase transformations.Comment: v3: 6p.(extended version), in press in Physical Review
Hodge Duality Operation And Its Physical Applications On Supermanifolds
An appropriate definition of the Hodge duality operation on any
arbitrary dimensional supermanifold has been a long-standing problem. We define
a working rule for the Hodge duality operation on the -dimensional supermanifold parametrized by a couple of even (bosonic)
spacetime variables and a couple of Grassmannian (odd)
variables and of the Grassmann algebra. The Minkowski
spacetime manifold, hidden in the supermanifold and parametrized by , is chosen to be a flat manifold on which a two -dimensional
(2D) free Abelian gauge theory, taken as a prototype field theoretical model,
is defined. We demonstrate the applications of the above definition (and its
further generalization) for the discussion of the (anti-)co-BRST symmetries
that exist for the field theoretical models of 2D- (and 4D) free Abelian gauge
theories considered on the four - (and six )-dimensional
supermanifolds, respectively.Comment: LaTeX file, 25 pages, Journal-versio
КЛІМАТИЧНІ ЗМІНИ ТА ЕКОНОМІЧНА ЕФЕКТИВНІСТЬ АГРАРНОГО ВИРОБНИЦТВА В СТЕПОВІЙ ЗОНІ
Relevance of research. Due to ongoing climate change, almost the entire territory of the Steppe of Ukraine by annual humidity factor belongs to the dry and very dry zones, the relative area of which has increased by 13.2% of the total area of the country compared to the 1960-1990s. At the same time, for today in Ukraine only about 500 thousand hectares are actually irrigated, that is 19% of the potential area.
Purpose of research. To determine the patterns and trends of climate change in the western part of the dry Steppe of Ukraine and analyze the economic indicators of production activity in the region as to the variable weather conditions.
Research methodology. Climate change was estimated on the basis of Climate Water Balance (CWB) and Hydrothermal Coefficient (HTC) values. The analysis of the economic efficiency of agricultural production was carried out by analyzing the statistical data for Odessa region and for the chosen agricultural enterprise.
Research results and conclusions. The use of significant heat supply in the dry Steppe zone is limited by insufficient water supply conditions. In the years of 1991-2016 the average annual rainfall was 480 mm and since the early 2000s there has been a slight increase in that. However, even having 500-550 mm of average annual rainfall that has been observed over the past five years, it is not enough for providing high-yield agricultural production. High thermal regime couses high evaporation that in turn, leads to water supply deficit, which at the end of the growing season amounts to 336-436 mm. According to the HTC index in the region 80% of cases show severe and moderately arid vegetation conditions. At the same time, irrigation area in the region has decreased to a minimum, which has led to the domination of winter cereals and sunflower in the cropping system. Under variable weather conditions, winter wheat yields ranged from 19.4 to 38.5 c/ ha (31.4 c/ha on average) and sunflower - from 12.2 to 21.4 c/ha (17.4 c/ha on average), winter rape - from 13.1 to 20.9 c/ha (18.2 c/ha). It was proved a close direct relationship between the sale price of products of all studied crops and their cost price, as well as the inverse relationship of these indicators with the crop yield. The profitability of winter wheat from 2011 till 2016 ranged from 17 to 153 USD/ha with an average value of 86 USD/ha, winter rape - from 39 to 273 USD/ha with an average value of 166 USD ha and sunflower - from 116 to 315 USD/ha with an average value of 192 USD/ha. Corn and soybeans have proven to be unprofitable in some years, which obviously explains rather small areas under these crops in the region.
Above mentioned demonstrates the high economic instability of agricultural production in changing weather conditions, which is accompanied by significant risks for producers, especially when attracting credits. This situation, in turn, leads to a limited use of intensification means, in particular mineral fertilizers, which promotes agrochemical soil degradation. Under unstable water supply, the magnitude of net profit variation per hectare of arable land in Odessa region is 33-188 USD/ha (111 USD/ha on average). It is possible to increase these indicators by increasing the share of winter rape in the cropping system. With the optimization of the water and air soil regimes as well as crop rotation factor, the profitability of agricultural production in the region can be increased up to 580-600 USD/ha. Similar results were obtained after analyzing the statistical data from the southern regions within the dry steppe zone.Внаслідок сучасних кліматичних змін майже вся територія Степу України за річним коефіцієнтом зволоження належить до сухої та дуже сухої зон, відносна площа яких збільшилась порівняно з 1960-1990 рр. на 13,2% до загальної площі країни. Водночас по Україні фактично поливається близько 500 тис. га або 19% від вихідної площі. В результаті досліджень встановлено, що використання високого рівня теплових ресурсів в сухостеповій зоні обмежується недостатніми умовами зволоження. За показником ГТК в регіоні у 80% випадків спостерігаються сильно та середньо посушливі умови вегетаційного періоду.
Встановлено існування тісної прямої залежності між ціною реалізації продукції всіх досліджуваних культур та їх собівартістю, а також зворотної залежності цих показників із врожайністю посівів. Прибутковість за 2011-2016 рр. коливалася: для пшениці озимої в межах 17-153 у.о./га із середнім значенням 86 у.о./га, ріпаку озимого - 39-273 у.о./га із середнім значенням 166 у.о./га, та соняшнику – 116-315 у.о./га із середнім значенням 192 у.о./га. Кукурудза і соя в окремі роки виявилися збитковими, що очевидно і визначає незначні площі їх посівів в регіоні. Це свідчить про високу економічну нестабільність виробничої діяльності у змінних погодних умовах, що супроводжується значними ризиками для виробників.
Загалом, за нестабільних умов зволоження амплітуда коливання чистого прибутку з одного гектара ріллі в Одеській області становить 33-188 у.о./га при середньому рівні 111 у.о./га. Дещо підвищити ці показники можна за збільшення частки в структурі посівних площ ріпака озимого. За оптимізації водно-повітряного режиму ґрунту та сівозмінного фактора прибутковість аграрного виробництва в регіоні можна довести до 580-600 у.о./га. Аналогічні показники отримано в результаті аналізу статистичних даних південних областей в межах сухостепової зони
(In)finite extensions of algebras from their Inonu-Wigner contractions
The way to obtain massive non-relativistic states from the Poincare algebra
is twofold. First, following Inonu and Wigner the Poincare algebra has to be
contracted to the Galilean one. Second, the Galilean algebra is to be extended
to include the central mass operator. We show that the central extension might
be properly encoded in the non-relativistic contraction. In fact, any
Inonu-Wigner contraction of one algebra to another, corresponds to an infinite
tower of abelian extensions of the latter. The proposed method is
straightforward and holds for both central and non-central extensions. Apart
from the Bargmann (non-zero mass) extension of the Galilean algebra, our list
of examples includes the Weyl algebra obtained from an extension of the
contracted SO(3) algebra, the Carrollian (ultra-relativistic) contraction of
the Poincare algebra, the exotic Newton-Hooke algebra and some others. The
paper is dedicated to the memory of Laurent Houart (1967-2011).Comment: 7 pages, revtex style; v2: Minor corrections, references added; v3:
Typos correcte
Measurement of Muon Capture on the Proton to 1% Precision and Determination of the Pseudoscalar Coupling g_P
The MuCap experiment at the Paul Scherrer Institute has measured the rate L_S
of muon capture from the singlet state of the muonic hydrogen atom to a
precision of 1%. A muon beam was stopped in a time projection chamber filled
with 10-bar, ultra-pure hydrogen gas. Cylindrical wire chambers and a segmented
scintillator barrel detected electrons from muon decay. L_S is determined from
the difference between the mu- disappearance rate in hydrogen and the free muon
decay rate. The result is based on the analysis of 1.2 10^10 mu- decays, from
which we extract the capture rate L_S = (714.9 +- 5.4(stat) +- 5.1(syst)) s^-1
and derive the proton's pseudoscalar coupling g_P(q^2_0 = -0.88 m^2_mu) = 8.06
+- 0.55.Comment: Updated figure 1 and small changes in wording to match published
versio
Measurement of the Rate of Muon Capture in Hydrogen Gas and Determination of the Proton's Pseudoscalar Coupling
The rate of nuclear muon capture by the proton has been measured using a new
experimental technique based on a time projection chamber operating in
ultra-clean, deuterium-depleted hydrogen gas at 1 MPa pressure. The capture
rate was obtained from the difference between the measured
disappearance rate in hydrogen and the world average for the decay
rate. The target's low gas density of 1% compared to liquid hydrogen is key to
avoiding uncertainties that arise from the formation of muonic molecules. The
capture rate from the hyperfine singlet ground state of the atom is
measured to be , from which the induced
pseudoscalar coupling of the nucleon, , is
extracted. This result is consistent with theoretical predictions for
that are based on the approximate chiral symmetry of QCD.Comment: submitted to Phys.Rev.Let
ОПТИМИЗАЦИЯ КОНСТРУКТИВНО-ТЕХНОЛОГИЧЕСКИХ ПАРАМЕТРОВ И ВЕРИФИКАЦИЯ ЭЛЕКТРИЧЕСКИХ ХАРАКТЕРИСТИК МОП-ТРАНЗИСТОРА С 0,35 МКМ ПРОЕКТНЫМИ НОРМАМИ
The description of the original integrated approach to solving the problem of statistical analysis in microelectronic products design process from the design of the technological routine to the system design. Testing of this methodology is described by investigating the influence of process parameters on dispersion structural and electrical characteristics of 0.35 micron MOS transistor, and the characteristics of the analog and digital circuit solutions.Представлено описание оригинального комплексного подхода к решению задачи статистического анализа в процессе сквозного проектирования изделий микроэлектроники от этапа проектирования технологического процесса до проектирования системы. Описано тестирование данной методики на примере исследования влияния разброса технологических параметров на конструктивные и электрические характеристики 0,35 мкм МОП-транзистора, а также на характеристики аналоговых и цифровых схемотехнических решений на его основе
Performance of the CMS Cathode Strip Chambers with Cosmic Rays
The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device
in the CMS endcaps. Their performance has been evaluated using data taken
during a cosmic ray run in fall 2008. Measured noise levels are low, with the
number of noisy channels well below 1%. Coordinate resolution was measured for
all types of chambers, and fall in the range 47 microns to 243 microns. The
efficiencies for local charged track triggers, for hit and for segments
reconstruction were measured, and are above 99%. The timing resolution per
layer is approximately 5 ns
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