702 research outputs found
Богородиця в українських колядках: функції, семантика образу
The author draws analogies in the activities of the ethnographic hoards. Their contribution to the Ukrainian folklore study is shown
Теоретичні аспекти процесу реструктуризації в умовах антикризового управління
У статті розкрито сутність поняття "реструктуризація", окреслено чинники, які викликають необхідність реструктуризаційних змін, визначено цілі та види реструктуризації, а також запропоновано ряд перспективних напрямів та відповідних заходів її проведення.Essence of concept "restructuring" is exposed in the article, outlined factors which cause the necessity of
restrukturizaciynikh changes, certainly aims and types of restructuring, and also the row of perspective directions
and proper measures of its leadthrough is offered
Study on the combined threshold for gully-type debris flow early warning
Gully-type debris flow induced by high-intensity and short-duration rainfall
frequently causes great loss of properties and causalities in mountainous
regions of southwest China. In order to reduce the risk by geohazards, early
warning systems have been provided. A triggering index can be detected in an
early stage by the monitoring of rainfall and the changes in physical
properties of the deposited materials along debris flow channels. Based on the
method of critical pore pressure for slope stability analysis, this study
presents critical pore pressure threshold in combination with rainfall
factors for gully-type debris flow early warning. The Wenjia gully, which
contains an enormous amount of loose material, was selected as a case study
to reveal the relationship between the rainfall and pore pressure by field
monitoring data. A three-level early warning system (zero, attention, and
warning) is adopted and the corresponding judgement conditions are defined in
real time. Based on this threshold, there are several rainfall events in
recent years have been validated in Wenjia gully, which prove that such a
combined threshold may be a reliable approach for the early warning of
gully-type debris flow to safeguard the population in the mountainous areas.</p
The application of numerical debris flow modelling for the generation of physical vulnerability curves
For a quantitative assessment of debris flow risk, it is essential to consider not only the hazardous process itself but also to perform an analysis of its consequences. This should include the estimation of the expected monetary losses as the product of the hazard with a given magnitude and the vulnerability of the elements exposed. A quantifiable integrated approach of both hazard and vulnerability is becoming a required practice in risk reduction management. This study aims at developing physical vulnerability curves for debris flows through the use of a dynamic run-out model. Dynamic run-out models for debris flows are able to calculate physical outputs (extension, depths, velocities, impact pressures) and to determine the zones where the elements at risk could suffer an impact. These results can then be applied to consequence analyses and risk calculations. On 13 July 2008, after more than two days of intense rainfall, several debris and mud flows were released in the central part of the Valtellina Valley (Lombardy Region, Northern Italy). One of the largest debris flows events occurred in a village called Selvetta. The debris flow event was reconstructed after extensive field work and interviews with local inhabitants and civil protection teams. The Selvetta event was modelled with the FLO-2D program, an Eulerian formulation with a finite differences numerical scheme that requires the specification of an input hydrograph. The internal stresses are isotropic and the basal shear stresses are calculated using a quadratic model. The behaviour and run-out of the flow was reconstructed. The significance of calculated values of the flow depth, velocity, and pressure were investigated in terms of the resulting damage to the affected buildings. The physical damage was quantified for each affected structure within the context of physical vulnerability, which was calculated as the ratio between the monetary loss and the reconstruction value. Three different empirical vulnerability curves were obtained, which are functions of debris flow depth, impact pressure, and kinematic viscosity, respectively. A quantitative approach to estimate the vulnerability of an exposed element to a debris flow which can be independent of the temporal occurrence of the hazard event is presented
Synchronisation of egg hatching of brown hairstreak (Thecla betulae) and budburst of blackthorn (Prunus spinosa) in a warmer future
Synchronisation of the phenology of insect herbivores and their larval food plant is essential for the herbivores’ fitness. The monophagous brown hairstreak (Thecla betulae) lays its eggs during summer, hibernates as an egg, and hatches in April or May in the Netherlands. Its main larval food plant blackthorn (Prunus spinosa) flowers in early spring, just before the leaves appear. As soon as the Blackthorn opens its buds, and this varies with spring temperatures, food becomes available for the brown hairstreak. However, the suitability of the leaves as food for the young caterpillars is expected to decrease rapidly. Therefore, the timing of egg hatch is an important factor for larval growth. This study evaluates food availability for brown hairstreak at different temperatures. Egg hatch and budburst were monitored from 2004 to 2008 at different sites in the Netherlands. Results showed ample food availability at all monitored temperatures and sites but the degree of synchrony varied strongly with spring temperatures. To further study the effect of temperature on synchronisation, an experiment using normal temperatures of a reference year (T) and temperatures of T + 5°C was carried out in climate chambers. At T + 5°C, both budburst and egg hatch took place about 20 days earlier and thus, on average, elevated temperature did not affect synchrony. However, the total period of budburst was 11 days longer, whereas the period of egg hatching was 3 days shorter. The implications for larval growth by the brown hairstreak under a warmer climate are considered.
Modelling the role of material depletion, grain coarsening and revegetation in debris flow occurrences after the 2008 Wenchuan earthquake
A large amount of debris was generated by the co-seismic mass wasting associated with the 2008 Mw 7.9 Wenchuan earthquake. The abundance of this loose material along the slopes caused more frequent debris flows, triggered by less intense and/or shorter rainfalls. However, both the triggering rainfall and the debris flow frequency seem to have normalised progressively during the past decade. Although changes of rainfall thresholds for post-seismic debris flows were recorded after several major earthquakes, the factors controlling these changes remain poorly constrained. With the aid of a virtual experiment, we investigate the roles of material depletion, grain coarsening and revegetation of the co-seismic debris on the propagation and deposition of debris flows initiated by runoff, as well as their influence on the triggering rainfall thresholds. We employ a Geographic Information System (GIS)-based simulation of debris flow initiation by runoff erosion, which we first calibrate on the 14th August 2010 Hongchun gully event that occurred near the Wenchuan earthquake epicentre. We obtain, by investigating each of the aforementioned processes, changing critical rainfall intensity-duration thresholds for given debris flow runout distances. Grain coarsening appears to play a major role, which is consistent with published laboratory experiments, while material depletion and revegetation do not seem able to account alone for the actual quick decay of debris flow frequency. While the virtual experiment has proven useful in identifying the first-order controls on this decay, model improvements and verification over multiple catchments are needed to make the results useful in hazard assessments
Het mosselbestand en het areaal aan mosselbanken op de droogvallende platen van de Waddenzee in het voorjaar van 2013
Onderzoek naar het areaal en bestand aan litorale mosselbanken in de Waddenzee. Doel is: Het maken van een biomassa-schatting van het mosselbestand op droogvallende platen in de Nederlandse Waddenzee in het voorjaar van 2013. Voor de kartering van het areaal aan mosselbanken worden bij laag water in de beschikbare tijd zo veel mogelijk banken te voet bezocht. Met behulp van GPS-apparatuur worden de positie en omtrek van de banken bepaald. Bij het bepalen van het totale areaal mosselbanken wordt voor de niet bezochte banken uitgegaan van gegevens in eerdere jaren, na middels een vliegtuig inspectie de aanwezigheid van deze banken vastgesteld te hebben
Het kokkelbestand in de Nederlandse kustwateren in 2012
In het voorjaar van 2012 is het kokkelbestand (Cerastoderma edule) in de Waddenzee, de Oosterschelde, de Westerschelde en de Voordelta geïnventariseerd. De inventarisatie wordt jaarlijks uitgevoerd ten behoeve van het beleid voor visserij, en is daarnaast ook van belang voor evaluatie van beheersmaatregelen en effectstudies in het kader van Natura 2000 en de natuurbeschermingswet. De kokkelbestandsopname wordt sinds 1990 uitgevoerd in de Oosterschelde en de Waddenzee, sinds 1992 in de Westerschelde en sinds 1993 in de Voordelta
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