255 research outputs found
THE CURRENT STATE OF THE VITIVINICULTURE SECTOR IN ROMANIA
After Romania accessed the European Union in 2007 and especially after 2009, there were major changes in Romania in the viticulture and winemaking field regarding the alignment of the legal framework to the Common Agricultural Policy (P.A.C.). During the post-accession, there were both important quality leaps in this field and a series of difficulties imposing a synthetic analysis in order to identify certain solutions to diversify the vineyard range and to improve the quality of the winemaking products.In this framework, concerning the strategies and policies implemented in the vitiviniculture sector in Romania during the last decade, this study refers to the following aspects: assessing the reconversion-restructuring stage of the vineyards in Romania, assessing the stage of implementing national strategies to produce high-quality wine (with PDO and PGI), as important premises for providing quality and specificity to the wine products
THERMAL REGIME DURING COLD ACCLIMATION AND DORMANT SEASON OF GRAPEVINES IN CONTEXT OF CLIMATE CHANGES- HILLS OF CRAIOVA VINEYARD (ROMANIA)
The thermal regime during the autumn-winter seasons plays a decisive role in cold acclimation and survival grapevine in cold climates. This study aims at assessing the time variability of the thermal regime during dormant season, between 1961-2021, in the Hills of Craiova vineyard and its potential implications on the grapevine, especially regarding its acclimation to cold and its vulnerability to frost. The following observations and analytical data were used in order to assess parameters and indicators with negative thermal stress potential: minimum and maximum temperature (daily, monthly averages), absolute maximum and minimum monthly temperatures, the duration of frost (days), the frequency of several low-temperature thresholds and the temperatures preceding frost episodes. Â
Miniature solid-state switched spiral generator for the cost effective, programmable triggering of large scale pulsed power accelerators
This paper presents the design and testing of several different configurations of spiral generator, designed to trigger high current switches in the next generation of pulsed power devices. In particular, it details the development of spiral generators that utilize new ultrafast thyristor technology as an input switch, along with a polarity dependent output gap to improve the efficiency of the spiral generator design. The generator produced 50 kV from a 3.6 kV charging voltage, with a rise time of only 50 ns and a jitter of 1.3 nsâdirectly comparable, if not better than, a generator employing a triggered spark gap as the input switch. The output gap was constructed in house from commonly available components and a 3D printed case, and showed remarkable repeatability and stabilityâsimple alterations to the output gap could further reduce the rise time. The entire spiral generator, along with control and charging electronics, fitted into a case only 210 Ă 145 Ă 33 â â mm
Sized Types for low-level Quantum Metaprogramming
One of the most fundamental aspects of quantum circuit design is the concept
of families of circuits parametrized by an instance size. As in classical
programming, metaprogramming allows the programmer to write entire families of
circuits simultaneously, an ability which is of particular importance in the
context of quantum computing as algorithms frequently use arithmetic over
non-standard word lengths. In this work, we introduce metaQASM, a typed
extension of the openQASM language supporting the metaprogramming of circuit
families. Our language and type system, built around a lightweight
implementation of sized types, supports subtyping over register sizes and is
moreover type-safe. In particular, we prove that our system is strongly
normalizing, and as such any well-typed metaQASM program can be statically
unrolled into a finite circuit.Comment: Presented at Reversible Computation 2019. Final authenticated
publication is available online at
https://doi.org/10.1007/978-3-030-21500-2_
Topology of amorphous tetrahedral semiconductors on intermediate lengthscales
Using the recently-proposed ``activation-relaxation technique'' for
optimizing complex structures, we develop a structural model appropriate to
a-GaAs which is almost free of odd-membered rings, i.e., wrong bonds, and
possesses an almost perfect coordination of four. The model is found to be
superior to structures obtained from much more computer-intensive tight-binding
or quantum molecular-dynamics simulations. For the elemental system a-Si, where
wrong bonds do not exist, the cost in elastic energy for removing odd-membered
rings is such that the traditional continuous-random network is appropriate.
Our study thus provides, for the first time, direct information on the nature
of intermediate-range topology in amorphous tetrahedral semiconductors.Comment: 4 pages, Latex and 2 postscript figure
5 years experience in epidermoid and dermoid cysts: Case presentation and literature review
Introduction: Intracranial epidermoid and dermoid cysts are the result of an embryogenesis dysfunction leading to an abnormal migration of ectodermal cells characterised by a slow and benign rate of growth which is associated with minimal neurological symptoms in large or giant tumors. Materials and methods: We retrospectively reviewed the case files of 17 patients with epidermoid and dermoid cysts operated using the operative microscope and neuronavigation in our department between January 2011 and December 2015. Results: Reviewing the case files we selected fourteen patients with epidermoid cysts and 3 patients with dermoid cysts who underwent surgical resection. Most of the cysts were located infratentorial (64%) with a propensity for the CP angle (81%). Total resection was attempted in all cases but was possible in only 13 cases. All cases with subtotal resection were infratentorially located in close relation to the brainstem or cranial nerves. Conclusion: When the tumor extension reaches beyond the limits of the surgical approach used, the tumor remnant should be addressed in a second surgery. Using the cysternal anatomy and the vessels dissection technique the risks aseptic meningitis and of injuring the cranial nerves are diminished
Modeling the non-Markovian, non-stationary scaling dynamics of financial markets
A central problem of Quantitative Finance is that of formulating a
probabilistic model of the time evolution of asset prices allowing reliable
predictions on their future volatility. As in several natural phenomena, the
predictions of such a model must be compared with the data of a single process
realization in our records. In order to give statistical significance to such a
comparison, assumptions of stationarity for some quantities extracted from the
single historical time series, like the distribution of the returns over a
given time interval, cannot be avoided. Such assumptions entail the risk of
masking or misrepresenting non-stationarities of the underlying process, and of
giving an incorrect account of its correlations. Here we overcome this
difficulty by showing that five years of daily Euro/US-Dollar trading records
in the about three hours following the New York market opening, provide a rich
enough ensemble of histories. The statistics of this ensemble allows to propose
and test an adequate model of the stochastic process driving the exchange rate.
This turns out to be a non-Markovian, self-similar process with non-stationary
returns. The empirical ensemble correlators are in agreement with the
predictions of this model, which is constructed on the basis of the
time-inhomogeneous, anomalous scaling obeyed by the return distribution.Comment: Throughout revision. 15 pages, 6 figures. Presented by A.L. Stella in
a Talk at the "Econophysics - Kolkata V'' International Workshop, March 2010,
Saha Institute of Nuclear Physics, Kolkata, Indi
Elevation changes of the Fennoscandian Ice Sheet interior during the last deglaciation
The dynamics of ice sheet interiors during the last deglaciation are poorly constrained, hindering evaluation of ice sheet models. We provide direct evidence of Fennoscandian Ice Sheet (FIS) interior behaviour during deglaciation through surface exposure dating. Our results demonstrate early thinning of the FIS, prior to the Younger Dryas (YD, 12.8â11.7 ka). Interior thinning in central Norway was concurrent with retreat along the coastline, exposing iceâfree mountainous tracts, potentially as early as 20â15 ka. The FIS then formed moraines in these iceâfree tracts during the YD. This is contrary to current hypotheses advocating a landscape fully covered by cold, inactive ice during this period. Present empirical and model reconstructions fail to capture rapid interior downâwastage, increasing uncertainties in ice sheet volume estimates and sea level contributions
Inferring transient dynamics of human populations from matrix non-normality
This is the final version of the article. Available from Springer Verlag via the DOI in this record.In our increasingly unstable and unpredictable world, population dynamics rarely settle uniformly to long-term behaviour. However, projecting period-by-period through the preceding fluctuations is more data-intensive and analytically involved than evaluating at equilibrium. To efficiently model populations and best inform policy, we require pragmatic suggestions as to when it is necessary to incorporate short-term transient dynamics and their effect on eventual projected population size. To estimate this need for matrix population modelling, we adopt a linear algebraic quantity known as non-normality. Matrix non-normality is distinct from normality in the Gaussian sense, and indicates the amplificatory potential of the population projection matrix given a particular population vector. In this paper, we compare and contrast three well-regarded metrics of non-normality, which were calculated for over 1000 age-structured human population projection matrices from 42 European countries in the period 1960 to 2014. Non-normality increased over time, mirroring the indices of transient dynamics that peaked around the millennium. By standardising the matrices to focus on transient dynamics and not changes in the asymptotic growth rate, we show that the damping ratio is an uninformative predictor of whether a population is prone to transient booms or busts in its size. These analyses suggest that population ecology approaches to inferring transient dynamics have too often relied on suboptimal analytical tools focussed on an initial population vector rather than the capacity of the life cycle to amplify or dampen transient fluctuations. Finally, we introduce the engineering technique of pseudospectra analysis to population ecology, which, like matrix non-normality, provides a more complete description of the transient fluctuations than the damping ratio. Pseudospectra analysis could further support non-normality assessment to enable a greater understanding of when we might expect transient phases to impact eventual population dynamics.This work was funded by Wellcome Trust New Investigator 103780 to TE, who is also funded by NERC Fellowship NE/J018163/1. JB gratefully acknowledges the ESRC Centre for Population Change ES/K007394/1
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