220 research outputs found
P\'olya number of continuous-time quantum walks
We propose a definition for the P\'olya number of continuous-time quantum
walks to characterize their recurrence properties. The definition involves a
series of measurements on the system, each carried out on a different member
from an ensemble in order to minimize the disturbance caused by it. We examine
various graphs, including the ring, the line, higher dimensional integer
lattices and a number of other graphs and calculate their P\'olya number. For
the timing of the measurements a Poisson process as well as regular timing are
discussed. We find that the speed of decay for the probability at the origin is
the key for recurrence.Comment: 8 pages, no figures. Accepted for publication in Physical Review
The use of GNSS zenith total delays in operational AROME/Hungary 3D-Var over a central European domain
The delay of satellite signals broadcasted by Global Navigation Satellite
System (GNSS) provides unique atmospheric observations which endorse
numerical weather prediction from global to limited-area models. Due to the
possibility of its frequent and near-real-time estimation, the zenith total
delays (ZTDs) are valuable information for any state-of-the-art data
assimilation system. This article introduces the data assimilation of ZTDs in
a Hungarian numerical weather prediction system, which was carried out by taking
into account observations from central European GNSS analysis and processing
centres. The importance of ZTD observations is described and shown by a
diagnostic tool in the 3-hourly updated 3D-Var assimilation
scheme. Furthermore, observing system experiments are done to evaluate the
impact of GNSS ZTDs on mesoscale limited-area forecasts. The results of the
use of GNSS ZTDs showed a clear added value to improve screen-level
temperature and humidity forecasts when the bias is accurately estimated and
corrected in the data assimilation scheme. The importance of variational, i.e.
adaptive bias correction, is highlighted by verification scores compared to
static bias correction. Moreover, this paper reviews the quality control of
GNSS ground-based stations inside the central European domain, the
calculation of optimal thinning distance and the preparation of the two
above-mentioned bias correction methods. Finally, conclusions are drawn on
different settings of the forecast and analysis experiments with a brief
future outlook.</p
A koherencia mint a lelki és testi egészség alapvető meghatározója a mai magyar társadalomban = Sense of coherence as an important determinant of mental and physical health
Az ún. salutogenezis modell olyan keretet kínál, amelyben a koherencia élmény bevezetésével lehetőség nyílik az „egész”-ség dinamikus értelmezésére. Vizsgálatunkban a Richard Rahe-féle, az „élet értelme” koherencia kérdőív összefüggéseit vizsgáltuk az egészségi állapottal. A Hungarostudy 2002 felmérés a 18 évesnél idősebb magyar népességet életkor, nem és terület szerint képviseli. 12 640 személlyel vettünk fel otthoni interjút. Az így vizsgált koherencia mutatót az egészségi állapot igen fontos előrejelzőjének találtuk. Ha az adatokat életkor, nem és iskolázottság szerint korrigáltuk, az egészségi állapot önbecslése mintegy 10-szer, a munkaképesség 8-szor jobb, a depresszió valószínűsége 7-szer alacsonyabb volt. Az „élet értelme” mutató igen szoros kapcsolatban áll az önhatékonysággal, a problémaorientált megbirkózással, a társas támogatással, ezzel szemben kevésbé függ az iskolázottságtól, az életkortól és a nemtől
Spore dispersal, diurnal pattern and viability of Monilinia spp. conidia and the relationship with weather components in an organic apple orchard
In a two-year Hungarian study, spore dispersal diurnal periodicity and viability of Monilinia spp. and their relation to weather components were determined in an organic apple orchard. Conidia of Monilinia spp. were first trapped in late May in both years. Low number of conidia were trapped until end-June. Thereafter, number of conidia continuously increased until harvest. Conidia in a 24-h period showed diurnal periodicity pattern, with th highest concentration in the afternoon hours. Spore viability with FDA staining showed that viability ofconidia ranged from 45 to 70% with showing lower viability in the dry than in the wet days in both years. Temperature and relative humidity correlated positively with mean hourly conidia numbers in both years. Mean hourly rainfall was negatively but poorly correlated with conidiacatches in both years. Results were compared and discussed with previous observations
Fruit injury in organic fruit production and its relationship to brown rot caused by Monilinia spp.
In a two-year Hungarian study, the temporal progress of brown rot incidence and various injury types were studied in organic fruit orchards and the relationship between brown rot and injury types was determined. Results showed that brown rot reached an almost 20% incidence level in both years. Total injury incidence reached up to 5.3 and 19.8% in the two years. In all cases, insect injury incidence was the highest among injury types in most assessment dates. Incidence levels of other injury types (bird injury, mechanical injury and other injury) began to increase, but none of those reached levels >4%. Pearson’s correlation coefficients showed that brown rot incidence correlated significantly with the incidence of insect injury. In addition, brown rot incidence and the incidence levels of bird injuries was also significantly correlated. High injury and brown rot incidence levels suggest further improvements on organic fruit protection
Spore dispersal, diurnal pattern and viability of Monilinia spp. conidia and the relationship with weather components in an organic apple orchard
In a two-year Hungarian study, spore dispersal diurnal periodicity and viability of Monilinia spp. and their relation to weathercomponents were determined in an organic apple orchard. Conidia of Monilinia spp. were first trapped in late May in both years. Low numberof conidia were trapped until end-June. Thereafter, number of conidia continuously increased until harvest. Conidia in a 24-h period showeddiurnal periodicity pattern, with th highest concentration in the afternoon hours. Spore viability with FDA staining showed that viability ofconidia ranged from 45 to 70% with showing lower viability in the dry than in the wet days in both years. Temperature and relative humiditycorrelated positively with mean hourly conidia numbers in both years. Mean hourly rainfall was negatively but poorly correlated with conidiacatches in both years. Results were compared and discussed with previous observations
Fruit injury in organic fruit production and its relationship to brown rot caused by Monilinia spp.
In a two-year Hungarian study, the temporal progress of brown rot incidence and various injury types were studiedin organic fruit orchards and the relationship between brown rot and injury types was determined. Results showed that brownrot reached an almost 20% incidence level in both years. Total injury incidence reached up to 5.3 and 19.8% in the two years.In all cases, insect injury incidence was the highest among injury types in most assessment dates. Incidence levels of otherinjury types (bird injury, mechanical injury and other injury) began to increase, but none of those reached levels >4%. Pearson’scorrelation coefficients showed that brown rot incidence correlated significantly with the incidence of insect injury. In addition,brown rot incidence and the incidence levels of bird injuries was also significantly correlated. High injury and brown rotincidence levels suggest further improvements on organic fruit protection
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