Model Checking Paxos in Spin

We present a formal model of a distributed consensus algorithm in the executable specification language Promela extended with a new type of guards, called counting guards, needed to implement transitions that depend on majority voting. Our formalization exploits abstractions that follow from reduction theorems applied to the specific case-study. We apply the model checker Spin to automatically validate finite instances of the model and to extract preconditions on the size of quorums used in the election phases of the protocol.Comment: In Proceedings GandALF 2014, arXiv:1408.556

ДРУГА СВІТОВА ВІЙНА ТА УКРАЇНА:ПОЛІТИЧНІ, СОЦІАЛЬНО-ЕКОНОМІЧНІ Й ДЕМОГРАФІЧНІ НАСЛІДКИ

Встатті висвітлюютьсяпитання повоєнної трансформації українського суспільства, вплив людських, демографічних та економічних втрат на подальший розвиток України.The article highlights the issue of post-war transformation ofUkrainian society, human impact, demographic and economic losses due to the further development of Ukraine

Primary producers and production in Hornsund and Kongsfjorden - Comparison of two fjord systems

Hornsund and Kongsfjorden are two similar-sized Arctic fjords on the West coast of Spitsbergen. They are influenced by cold coastal Arctic water (Hornsund) and warmer Atlantic water (Kongsfjorden). Environmental conditions affect the timing, quantity, spatial distribution (horizontal and vertical) of spring and summer blooms of protists as well as the taxonomic composition of those assemblages. Here, we compile published data and unpublished own measurement from the past two decades to compare the environmental factors and primary production in two fjord systems. Kongsfjorden is characterized by a deeper euphotic zone, higher biomass and greater proportion of autotrophic species. Hornsund seems to obtain more nutrients due to the extensive seabird colonies and exhibits higher turbidity compared to Kongsfjorden. The annual primary production in the analysed fjords ranges from 48 g C m-2 y-1 in Kongsfjorden to 216 g C m-2 y-1 in Hornsund, with a dominant component of microplankton (90%) followed by macrophytes and microphytobenthos

Seasonality of occurrence and recruitment of Arctic marine benthic invertebrate larvae in relation to environmental variables

The Arctic system is one of the regions most influenced by ongoing global climate change, but there are still critical gaps in our knowledge regarding a substantial number of biological processes. This is especially true for processes taking place during the Arctic winter but also for seasonal processes, such as the dynamics of intra-annual meroplankton occurrence. Here, we report on a 1-year study of meroplankton seasonal variability from a fjordic system in the Arctic Archipelago of Svalbard. The study combines an examination of phytoplankton, zooplankton, and hard bottom benthic settlement with measurements of environmental parameters (e.g., water temperature, particulate organic matter, and dissolved organic carbon). Samples were taken on a bi-weekly or monthly basis, and a total of 11 taxa representing six phyla of meroplankton were recorded over a 1-year period from January to December 2007. The occurrence of benthic larvae varied between the seasons, reaching a maximum in both abundance and taxon richness in late spring through early summer. Meroplanktonic larvae were absent in winter. However, settlement of benthic organisms was also recorded during the winter months (February and March), which indicates individual trade-offs related to timing of reproduction and competition. In addition, it suggests that these larvae are not relying on higher summer nutrient concentrations, but instead are dependent on alternative food sources. In parallel with meroplankton abundance, all other measured parameters, both biological (e.g., phyto- and zooplankton abundance and diversity) and physical (e.g., particulate organic matter), exhibited seasonal variability with peaks in the warmer months of the year

Air pollution and related respiratory diseases: the experience of a Local Health Authority in Liguria (North Italy)

Background. Numerous epidemiological studies have shown that air pollution due to both industry and heavy traffic has short- and long-term effects on health. The study was carried out in an industrial area with heavy urban and motorway traffic in the Province of Genoa (Italy). Methods. The study was carried out from June 2005 to July 2008. An epidemiologic study was conducted by monitoring an elementary/ middle school situated in an area of recent industrial development and an elementary/middle school located in an area free from sources of industrial pollution. Furthermore, we conducted an investigation of workers in commercial premises situated in one area of heavy vehicular traffic. In the study areas, environmental monitoring campaigns were carried out in order to determine the association between indoor and outdoor pollution and respiratory disorders. Results and discussion. The study did not bring to light any specific health problems attributable with certainty to industrial emissions. The impact of pollution caused by motor traffic proved to be greater than that due to industrial emissions. More exhaustive sampling campaigns should be implemented in order to quantify the effects of specific sources of emissions and to correlate these sources with pollutants (industry, urban traffic, motorway traffic)

A survey-based assessment of seagrass status, management and legislation in Europe

Seagrass meadows are ranked amongst the most productive ecosystems on Earth, providing high-value ecosystem services in coastal areas. Yet, seagrass habitats are declining worldwide at an unprecedented rate as a consequence of both anthropogenic and natural pressures, which suggests an inefficient management. Seagrasses are widespread along European coasts and the knowledge on their conservation status and management has been increased in the last decade although an overall view for the whole Europe is lacking. The general aim of this survey-based study was to assess the present status of seagrass habitat conservation, management and legislation in Europe based on the expert judgement of 25 participants from 19 coastal European countries. We specifically assessed the seagrass ecological status and their major threats; the level of awareness; the effort in mapping, monitoring and restoration; and the state of management plans and policy in each country. We furthermore reviewed the legislation for seagrass habitats in order to assess the protection status of seagrasses in Europe. The survey-based assessment revealed great differences among seagrass species and countries regarding their awareness, ecological status, mapping, monitoring and management. Several good examples of seagrass management, in cooperation with scientists, were identified although many countries still lack the fundamental tools for a proper management. A consistent body of legislation was compiled for most European countries, yet their implementation was reported to be rather variable and weak. The results of this study will provide guidelines for a more effective seagrass management and policy in Europe.info:eu-repo/semantics/publishedVersio

Bibliyometrik Yöntemlerle Dünya Üniversitelerinin Değerlendirilmesinde Karşılaşılan Zorluklar

URAP Araştırma Laboratuvarı, 2009 yılında Enformatik Enstitüsü bünyesinde kurulmuş olup yükseköğretim kurumlarını akademik performansları doğrultusunda değerlendirebilmek için bilimsel metodlar geliştirmeyi hedefler

Carbon export in the seasonal sea ice zone north of Svalbard from winter to late summer

Phytoplankton blooms in the Arctic Ocean's seasonal sea ice zone are expected to start earlier and occur further north with retreating and thinning sea ice cover. The current study is the first compilation of phytoplankton bloom development and fate in the seasonally variable sea ice zone north of Svalbard from winter to late summer, using short-term sediment trap deployments. Clear seasonal patterns were discovered, with low winter and pre-bloom phytoplankton standing stocks and export fluxes, a short and intense productive season in May and June, and low Chl a standing stocks but moderate carbon export fluxes in the autumn post-bloom conditions. We observed intense phytoplankton blooms with Chl a standing stocks of >350 mg m−2 below consolidated sea ice cover, dominated by the prymnesiophyte Phaeocystis pouchetii. The largest vertical organic carbon export fluxes to 100 m, of up to 513 mg C m−2 day−1, were recorded at stations dominated by diatoms, while those dominated by P. pouchetii recorded carbon export fluxes up to 310 mg C m−2 day−1. Fecal pellets from krill and copepods contributed a substantial fraction to carbon export in certain areas, especially where blooms of P. pouchetii dominated and Atlantic water advection was prominent. The interplay between the taxonomic composition of protist assemblages, large grazers, distance to open water, and Atlantic water advection was found to be crucial in determining the fate of the blooms and the magnitude of organic carbon exported out of the surface water column. Previously, the marginal ice zone was considered the most productive region in the area, but our study reveals intense blooms and high export events in ice-covered waters. This is the first comprehensive study on carbon export fluxes for under-ice phytoplankton blooms, a phenomenon suggested to have increased in importance under the new Arctic sea ice regime

Benchmarking van der Waals Density Functionals with Experimental Data: Potential Energy Curves for H2 Molecules on Cu(111), (100), and (110) Surfaces

Detailed physisorption data from experiment for the H_2 molecule on low-index Cu surfaces challenge theory. Recently, density-functional theory (DFT) has been developed to account for nonlocal correlation effects, including van der Waals (dispersion) forces. We show that the functional vdW-DF2 gives a potential-energy curve, potential-well energy levels, and difference in lateral corrugation promisingly close to the results obtained by resonant elastic backscattering-diffraction experiments. The backscattering barrier is found selective for choice of exchange-functional approximation. Further, the DFT-D3 and TS-vdW corrections to traditional DFT formulations are also benchmarked, and deviations are analyzed.Comment: 15 pages, 9 figure

An amphipathic helix in Brl1 is required for nuclear pore complex biogenesis in S. cerevisiae

The nuclear pore complex (NPC) is the central portal for macromolecular exchange between the nucleus and cytoplasm. In all eukaryotes, NPCs assemble into an intact nuclear envelope (NE) during interphase, but the process of NPC biogenesis remains poorly characterized. Furthermore, little is known about how NPC assembly leads to the fusion of the outer and inner NE, and no factors have been identified that could trigger this event. Here, we characterize the transmembrane protein Brl1 as an NPC assembly factor required for NE fusion in budding yeast. Brl1 preferentially associates with NPC assembly intermediates and its depletion halts NPC biogenesis, leading to NE herniations that contain inner and outer ring nucleoporins but lack the cytoplasmic export platform. Furthermore, we identify an essential amphipathic helix in the luminal domain of Brl1 that mediates interactions with lipid bilayers. Mutations in this amphipathic helix lead to NPC assembly defects, and cryo-electron tomography analyses reveal multilayered herniations of the inner nuclear membrane with NPC-like structures at the neck, indicating a failure in NE fusion. Taken together, our results identify a role for Brl1 in NPC assembly and suggest a function of its amphipathic helix in mediating the fusion of the inner and outer nuclear membranes.publishedVersio