51 research outputs found

    Tidewater glaciers as feeding spots for the Black-legged Kittiwake (Rissa tridactyla): A citizen science approach

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    Thirty-one tidewater glacier bays in Spitsbergen Island were visited by yachts in August 2011, 2015, 2016 and 2017. Surface water samples were taken by volunteers, the members of the yacht crews, to measure concentrations of suspended matter, salinity, and temperature. Secchi disc measurements were used to measure water transparency. A series of photographs along the glacier fronts were taken and used to count seabirds that were present near the glacier cliff. Basic topographic features (depth, presence of a sill, exposure, glacier width) were obtained from sea charts and analysed. The number of preying Black-legged Kittiwakes (Rissa tridactyla; a target species) ranged from zero to over 2000 birds during 89 visits. High concentrations of individuals (above 100) were observed in 20% of the visits, while no birds were recorded in 42% of the visits. There was no statistical correlation between the topographic features of the glacier and bird concentrations. To our present knowledge, Black-legged Kittiwake feeding spots are random and temporary in time in which (or soon after) the juveniles are leaving the colony. They are a recurrent phenomenon related to krill abundance and simultaneous jet-like meltwater discharges

    Multidecadal (1960–2011) shoreline changes in Isbjørnhamna (Hornsund, Svalbard)

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    A section of a gravel-dominated coast in Isbjørnhamna (Hornsund, Svalbard) was analysed to calculate the rate of shoreline changes and explain processes controlling coastal zone development over last 50 years. Between 1960 and 2011, coastal landscape of Isbjørnhamna experienced a significant shift from dominated by influence of tide-water glacier and protected by prolonged sea-ice conditions towards storm-affected and rapidly changing coast. Information derived from analyses of aerial images and geomorphological mapping shows that the Isbjørnhamna coastal zone is dominated by coastal erosion resulting in a shore area reduction of more than 31,600 m2. With ~3,500 m2 of local aggradation, the general balance of changes in the study area of the shore is negative, and amounts to a loss of more than 28,000 m2. Mean shoreline change is −13.1 m (−0.26 m a−1). Erosional processes threaten the Polish Polar Station infrastructure and may damage of one of the storage buildings in nearby future

    Biohydrogen and Biomethane (Biogas) Production in the Consecutive Stages of Anaerobic Digestion of Molasses

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    Anaerobic digestion, whose final products are methane and carbon dioxide, has been used to produce biogas from waste biomass as an alternative energy source. For the purpose of innovative, modern technologies based on microbial processes, it is desirable to separate the hydrogen- (hydrolysis and acidogenesis) and methane-yielding (acetogenesis and methanogenesis) stages of anaerobic digestion to respectively favor the production of hydrogen and methane under controlled conditions. Previously, we developed a benchscale (3- and 3.5-litre bioreactors) two-stage anaerobic digestion system producing hydrogen (in stage 1)and methane (in stage 2) from sucrose-rich by-products of the sugar beet refining industry as the primary energy substrates under mesophilic conditions. Recently, the two-stage system for hydrogen and methane production has been successfully scaled up 10-fold (a pilot scale) and currently operates in one of the Polish sugar factories. The efficiency of hydrogen and methane production were directly proportional to the scale of installation. The obtained results led to the development objectives of further research that the end result will be an innovative solution for the sugar factory as a producer of gaseous biofuels

    Dynamics and Complexity of Dark Fermentation Microbial Communities Producing Hydrogen From Sugar Beet Molasses in Continuously Operating Packed Bed Reactors

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    This study describes the dynamics and complexity of microbial communities producing hydrogen-rich fermentation gas from sugar-beet molasses in five packed-bed reactors (PBRs). The bioreactors constitute a part of a system producing hydrogen from the by-products of the sugar-beet industry that has been operating continuously in one of the Polish sugar factories. PBRs with different working volumes, packing materials, construction and inocula were tested. This study focused on analysis (based on 16S rRNA profiling and shotgun metagenomics sequencing) of the microbial communities selected in the PBRs under the conditions of high (>100 cm3/g COD of molasses) and low (<50 cm3/g COD of molasses) efficiencies of hydrogen production. The stability and efficiency of the hydrogen production are determined by the composition of dark fermentation microbial communities. The most striking difference between the tested samples is the ratio of hydrogen producers to lactic acid bacteria. The highest efficiency of hydrogen production (130-160 cm3/g COD of molasses) was achieved at the ratios of HPB to LAB ≈ 4:2.5 or 2.5:1 as determined by 16S rRNA sequencing or shotgun metagenomics sequencing, respectively. The most abundant Clostridium species were C. pasteurianum and C. tyrobutyricum. A multiple predominance of LAB over HPB (3:1-4:1) or clostridia over LAB (5:1-60:1) results in decreased hydrogen production. Inhibition of hydrogen production was illustrated by overproduction of short chain fatty acids and ethanol. Furthermore, concentration of ethanol might be a relevant marker or factor promoting a metabolic shift in the DF bioreactors processing carbohydrates from hydrogen-yielding toward lactic acid fermentation or solventogenic pathways. The novelty of this study is identifying a community balance between hydrogen producers and lactic acid bacteria for stable hydrogen producing systems. The balance stems from long-term selection of hydrogen-producing microbial community, operating conditions such as bioreactor construction, packing material, hydraulic retention time and substrate concentration. This finding is confirmed by additional analysis of the proportions between HPB and LAB in dark fermentation bioreactors from other studies. The results contribute to the advance of knowledge in the area of relationships and nutritional interactions especially the cross-feeding of lactate between bacteria in dark fermentation microbial communities

    Population genomics of the Viking world.

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    The maritime expansion of Scandinavian populations during the Viking Age (about AD 750-1050) was a far-flung transformation in world history1,2. Here we sequenced the genomes of 442 humans from archaeological sites across Europe and Greenland (to a median depth of about 1×) to understand the global influence of this expansion. We find the Viking period involved gene flow into Scandinavia from the south and east. We observe genetic structure within Scandinavia, with diversity hotspots in the south and restricted gene flow within Scandinavia. We find evidence for a major influx of Danish ancestry into England; a Swedish influx into the Baltic; and Norwegian influx into Ireland, Iceland and Greenland. Additionally, we see substantial ancestry from elsewhere in Europe entering Scandinavia during the Viking Age. Our ancient DNA analysis also revealed that a Viking expedition included close family members. By comparing with modern populations, we find that pigmentation-associated loci have undergone strong population differentiation during the past millennium, and trace positively selected loci-including the lactase-persistence allele of LCT and alleles of ANKA that are associated with the immune response-in detail. We conclude that the Viking diaspora was characterized by substantial transregional engagement: distinct populations influenced the genomic makeup of different regions of Europe, and Scandinavia experienced increased contact with the rest of the continent

    The Effect of Harvest Date and Storage Conditions on the Quality of Remontant Strawberry Cultivars Grown in a Gutter System under Covers

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    The storage characteristics of three remontant strawberry cultivars San Andreas&reg;, Albion&reg; and Murano&reg; were studied in 2018&ndash;2020. The short-term storage conditions (7 days) of strawberries used in the study significantly affected fruit quality indicators. The highest quality of stored strawberries was provided by controlled atmosphere (CA) conditions, as evidenced by the typically highest fruit firmness and the lowest natural loss of strawberry weight. The modified atmosphere packaging (MAP) conditions obtained in the Xtend&reg; bags provided a similar good storage effect for strawberries. Strawberries stored in MAP bags had the lowest respiratory intensity, and their firmness and the percentage of rotten fruit were the same as those stored in a controlled atmosphere. In addition, MAP bags were effective in reducing the weight loss of stored strawberries. The quality of strawberries stored in a conventional air storage (AA) was slightly lower compared to the fruit stored in a controlled and modified atmosphere. This was due to their lower firmness and significantly higher respiration intensity and higher weight loss. In addition, the percentage of rotten fruit, although low, has always been the highest among AA strawberries. The quality of the strawberries also depended on the date of fruit harvest. Strawberries harvested later, compared to those collected earlier, were generally characterized by higher firmness, lower acidity and lower respiration intensity

    Simulator sickness in the aircraft training of military and civil pilots of various types of aircraft

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    Wstęp Wraz z większą popularnością i dostępnością szkoleń symulatorowych wykorzystywanych do treningu pilotów zaobserwowano pojawianie się licznych efektów ubocznych tej technologii. Objawy choroby symulatorowej są zbliżone do dolegliwości związanych z chorobą lokomocyjną – m.in. zawroty głowy, wymioty, a także dezorientacja przestrzenna oraz ograniczenie zdolności koncentracji. Zależą one jednak od indywidualnych predyspozycji użytkowników symulatorów. Materiał i metody Celem pracy była ocena prawdopodobieństwa wystąpienia choroby symulatorowej podczas ćwiczeń w wirtualnej rzeczywistości oraz jej wpływu na efektywność szkolenia. Próba badawcza liczyła 32 wojskowych i 16 cywilnych pilotów różnych typów statków powietrznych. W celu subiektywnej oceny stanu psychofizycznego pilotów wykorzystano ankietę wzorowaną na Simulator Sickness Questionnaire (SSQ). Wyniki Wyodrębniono 4 główne czynniki wpływające na możliwość wystąpienia choroby symulatorowej: wiek badanej osoby, zróżnicowanie misji, rodzaj statku powietrznego i podatność na chorobę lokomocyjną. Wnioski W związku z indywidualnymi predyspozycjami badanych pilotów określenie ryzyka wystąpienia choroby symulatorowej wydaje się trudne. Istnieją jednak czynniki, które zwiększają prawdopodobieństwo zachorowania – przeziębienie, spożywane leki, niedobór snu i ogólne zmęczenie. Niepokojący jest brak wiedzy na temat choroby symulatorowej wśród pilotów. Warto zatem zastanowić się nad możliwościami edukacji tej grupy zawodowej w tym zakresie, przede wszystkim w celu uzyskiwania lepszych wyników w sesjach symulatorowych, w sytuacji łatwego dostępu do wirtualnej rzeczywistości. Med. Pr. 2019;70(3):317–325Background With the rise in popularity and availability of simulators for the aircraft training of pilots, numerous side effects of that technology have been noted among their users. The symptoms of simulator sickness are similar to the symptoms of motion sickness. Dizziness, nausea, as well as spatial disorientation and a limited capacity for concentration may be observed. However, those symptoms depend on individual user’s predispositions. Material and Methods The aim of the research was to assess the probability of occurrence of simulator sickness during exercises in virtual reality, and its impact on the effectiveness of training. Thirty two military and 16 civilian pilots of various types of aircraft took part in the research. For the subjective assessment of the psychophysical condition of the pilots, a questionnaire based on Simulator Sickness Questionnaire (SSQ) was used. Results Four main factors that are associated with the prevalence of simulator sickness have been identified, i.e., age, a variety of missions, a type of aircraft and susceptibility to motion sickness. Conclusions Due to the individual characteristics of each person, determining the risk of occurrence of simulator sickness seems to be difficult. However, there are some factors that increase the probability of getting sick, including cold, medications, lack of sleep and general fatigue. The lack of knowledge about simulator sickness among aircraft pilots appears rather alarming. When access to virtual reality is so wide, the possible ways of expanding the knowledge in this area should be considered, especially in order to obtain better results in simulator sessions. Med Pr. 2019;70(3):317–2
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