In mountainous regions, climate warming is expected to shift species' ranges to higher altitudes. Evidence for such shifts is still mostly from revisitations of historical sites. We present recent ...(2001 to 2008) changes in vascular plant species richness observed in a standardized monitoring network across Europe's major mountain ranges. Species have moved upslope on average. However, these shifts had opposite effects on the summit floras' spedes richness in boreal-temperate mountain regions (+3.9 species on average) and Mediterranean mountain regions (-1.4 species), probably because recent climatic trends have decreased the availability of water in the European south. Because Mediterranean mountains are particularly rich in endemic species, a continuation of these trends might shrink the European mountain flora, despite an average increase in summit species richness across the region.
Summary Background Non-thermal plasma has received much attention for elimination of microbial contamination from a range of surfaces. Aim This study aimed to determine the effect of a range of ...dielectric barrier discharge high voltage atmospheric cold plasma (HVACP) parameters for inactivation of Bacillus atrophaeus spores inside a sealed package. Methods A sterile polystyrene Petri dish containing B. atrophaeus spore strip (spore population 2.3 × 106 /strip i.e. 6.36 log10 /strip) was placed in a sealed polypropylene container and was subjected to HVACP treatment. The HVACP discharge was generated between two aluminium plate electrodes using a high voltage of 70 kVRMS . The effects of process parameters, including treatment time, mode of exposure (direct/indirect), and working gas types, were evaluated. The influence of relative humidity on HVACP inactivation efficacy was also assessed. The inactivation efficacy was evaluated using colony counts. Optical absorption spectroscopy (OAS) was used to assess gas composition following HVACP exposure. Findings A strong effect of process parameters on inactivation was observed. Direct plasma exposure for 60 s resulted in ≥6 log10 cycle reduction of spores in all gas types tested. However, indirect exposure for 60 s resulted in either 2.1 or 6.3 log10 cycle reduction of spores depending on gas types used for HVACP generation. The relative humidity (RH) was a critical factor in bacterial spore inactivation by HVACP, where a major role of plasma-generated species other than ozone was noted. Direct and indirect HVACP exposure for 60 s at 70% RH recorded 6.3 and 5.7 log10 cycle reduction of spores, respectively. Conclusion In summary, a strong influence of process parameters on spore inactivation was noted. Rapid in-package HVACP inactivation of bacterial spores within 30–60 s demonstrates the promising potential application for reduction of spores on medical devices and heat-sensitive materials.
Atmospheric cold plasmas (ACPs) have received increased attention in recent years as a novel decontamination technology in food and biological sciences research. Cold plasma treatment is especially ...desirable in food industries for in-package decontamination as it prevents post-processing contamination. ACPs are often obtained using noble gases or air. This work reports the decontamination of strawberries inside a sealed package with two different gas mixtures, viz. 65 % O₂ + 16 % N₂ + 19 % CO₂ and 90 % N₂ + 10 % O₂. The electrical parameters of the dielectric barrier discharge obtained at 60 kV rms (50 Hz) applied voltage over a 40-mm gap have been characterised using capacitive (charge–voltage) measurements and show for each gas mixture an increase in transferred power and charge in the presence of the fresh produce. The background micro-flora of the strawberries was reduced by an average of ~3.0 log cycles from the initial levels of 5 log₁₀ CFU/g in 300 s of in-package ACP discharge. Plasma treatments with the two gas mixtures showed similar effects on microbial reduction levels. Strawberries treated and stored in a high oxygen gas mixture showed favourable quality results with similar respiration rates and an 11 % higher firmness than the control stored for 24 h.
•In-package cold plasma treatment of strawberries based on dielectric barrier plasma discharge.•Electrical characterisation of the plasma discharge revealed a filamentary regime and ozone ...production.•A significant background microflora reduction was achieved.•No adverse changes in respiration rates, texture and colour of treated strawberries.
The ability to generate low temperature plasma at atmospheric pressure offers new opportunities to decontaminate biological materials, including fresh foods. In this study, strawberries were treated with atmospheric cold plasma (ACP), generated with a 60kV dielectric barrier discharge (DBD) pulsed at 50Hz, across a 40mm electrode gap, generated inside a sealed package containing ambient air (42% relative humidity). The current–voltage characteristics revealed that the plasma operated in the filamentary regime. The background microflora (aerobic mesophillic bacteria, yeast and mould) of strawberries treated for 5min was reduced by 2 log10 within 24h of post-ACP treatment. The respiration rate of ACP treated produce, measured by the closed system approach, showed no significant increase. The effect of ACP on strawberry colour and firmness was insignificant.
ABSTRACT The third catalog of active galactic nuclei (AGNs) detected by the Fermi-LAT (3LAC) is presented. It is based on the third Fermi-LAT catalog (3FGL) of sources detected between 100 MeV and ...300 GeV with a Test Statistic greater than 25, between 2008 August 4 and 2012 July 31. The 3LAC includes 1591 AGNs located at high Galactic latitudes ( ), a 71% increase over the second catalog based on 2 years of data. There are 28 duplicate associations, thus 1563 of the 2192 high-latitude gamma-ray sources of the 3FGL catalog are AGNs. Most of them (98%) are blazars. About half of the newly detected blazars are of unknown type, i.e., they lack spectroscopic information of sufficient quality to determine the strength of their emission lines. Based on their gamma-ray spectral properties, these sources are evenly split between flat-spectrum radio quasars (FSRQs) and BL Lacs. The most abundant detected BL Lacs are of the high-synchrotron-peaked (HSP) type. About 50% of the BL Lacs have no measured redshifts. A few new rare outliers (HSP-FSRQs and high-luminosity HSP BL Lacs) are reported. The general properties of the 3LAC sample confirm previous findings from earlier catalogs. The fraction of 3LAC blazars in the total population of blazars listed in BZCAT remains non-negligible even at the faint ends of the BZCAT-blazar radio, optical, and X-ray flux distributions, which hints that even the faintest known blazars could eventually shine in gamma-rays at LAT-detection levels. The energy-flux distributions of the different blazar populations are in good agreement with extrapolation from earlier catalogs.
While climatic research about treeline has a long history, the climatic conditions corresponding to the upper limit of closed alpine grasslands remain poorly understood. Here, we propose a climatic ...definition for this limit, the ‘grassline’, in analogy to the treeline, which is based on the growing season length and the soil temperature. Eighty-seven mountain summits across ten European mountain ranges, covering three biomes (boreal, temperate, Mediterranean), were inventoried as part of the GLORIA project. Vascular plant cover was estimated visually in 326 plots of 1 × 1 m. Soil temperatures were measured in situ for 2–7 years, from which the length of the growing season and mean temperature were derived. The climatic conditions corresponding to 40% plant cover were defined as the thresholds for alpine grassland. Closed vegetation was present in locations with a mean growing season soil temperature warmer than 4.9 °C, or a minimal growing season length of 85 days, with the growing season defined as encompassing days with daily mean ≥ 1 °C. Hence, the upper limit of closed grasslands was associated with a mean soil temperature close to that previously observed at the treeline, and in accordance with physiological thresholds to growth in vascular plants. In contrast to trees, whose canopy temperature is coupled with air temperature, small-stature alpine plants benefit from the soil warmed by solar radiation and consequently, they can grow at higher elevations. Since substrate stability is necessary for grasslands to occur at their climatic limit, the grassline rarely appears as a distinct linear feature.
PDF
