128 research outputs found
Air temperature variations and gradients along the coast and fjords of western Spitsbergen
Daily temperature measurements from six meteorological stations along the coast and fjords of western Spitsbergen have been digitized and quality controlled in a Norwegian, Russian and Polish collaboration. Complete daily data series have been reconstructed back to 1948 for all of the stations. One of the station’s monthly temperature series has previously been extended back to 1898 and is included in this study. The long-term series show large temperature variability on western Spitsbergen with colder periods in the 1910s and 1960s and warmer periods in the 1930s, 1950s and in the 21st century. The most recent years are the warmest ones in the instrumental records. There is a
positive and statistically significant trend in the annual times series for all of the stations; however, the strongest warming is seen in winter and spring. For the period 1979-2015, the linear trends range from 1.0 to 1.38°C/decade for the annual series and from 2.0 to 2.38°C/decade in winter. Threshold statistics demonstrate a decrease in the number of cold days per year and an increase in the number of warm days. A decreasing inter-annual variability is observed. In winter, spring and autumn, the stations in the northernmost areas of west Spitsbergen and in the innermost parts of Isfjorden are the coldest ones. In summer, however, the southernmost station is the coldest one
The interaction of wood nanocellulose dressings and the wound pathogen P. aeruginosa
Chronic wounds pose an increasingly significant worldwide economic burden (over £1 billion per annum in the UK alone). With the escalation in global obesity and diabetes, chronic wounds will increasingly be a significant cause of morbidity and mortality. Cellulose nanofibrils (CNF) are highly versatile and can be tailored with specific physical properties to produce an assortment of three-dimensional structures (hydrogels, aerogels or films), for subsequent utilization as wound dressing materials. Growth curves using CNF (diameter 0.05) over 24 h. These data demonstrate the potential of nanocellulose materials in the development of novel dressings that may afford significant clinical potential
The International Surface Pressure Databank version 2
The International Surface Pressure Databank (ISPD) is the world's largest collection of global surface and sea-level pressure observations. It was developed by extracting observations from established international archives, through international cooperation with data recovery facilitated by the Atmospheric Circulation Reconstructions over the Earth (ACRE) initiative, and directly by contributing universities, organizations, and countries. The dataset period is currently 1768–2012 and consists of three data components: observations from land stations, marine observing systems, and tropical cyclone best track pressure reports. Version 2 of the ISPD (ISPDv2) was created to be observational input for the Twentieth Century Reanalysis Project (20CR) and contains the quality control and assimilation feedback metadata from the 20CR. Since then, it has been used for various general climate and weather studies, and an updated version 3 (ISPDv3) has been used in the ERA-20C reanalysis in connection with the European Reanalysis of Global Climate Observations project (ERA-CLIM). The focus of this paper is on the ISPDv2 and the inclusion of the 20CR feedback metadata. The Research Data Archive at the National Center for Atmospheric Research provides data collection and access for the ISPDv2, and will provide access to future versions
Cellulose nanofibril formulations incorporating a low molecular weight alginate oligosaccharide modify bacterial biofilm development
Cellulose nanofibrils (CNFs) from wood pulp are a renewable material possessing advantages for biomedical applications, due to their customizable porosity, mechanical strength, translucency and environmental biodegradability. Here we investigated the growth of multi-species wound biofilms on CNF formulated as aerogels and films incorporating the low molecular weight alginate oligosaccharide OligoG CF-5/20 to evaluate their structural and antimicrobial properties. Overnight microbial cultures were adjusted to 2.8 x 109 colony forming units (cfu) mL-1 in Mueller Hinton broth and growth rates of P. aeruginosa PAO1 and S. aureus 1061A monitored for 24 h in CNF dispersions sterilized by γ-irradiation. Two CNF formulations were prepared (20 g m-2) with CNF as air-dried films or freeze-dried aerogels, with or without incorporation of an antimicrobial alginate oligosaccharide (OligoG CF-5/20) as a surface coating or bio-nanocomposite respectively. The materials were structurally characterized by Scanning Electron Microscopy (SEM) and laser profilometry (LP). The antimicrobial properties of the formulations were assessed using single- and mixed-species biofilms grown on the materials and analysed using LIVE/DEAD® staining with confocal laser scanning microscopy (CLSM) and COMSTAT software. OligoG-CNF suspensions significantly decreased the growth of both bacterial strains at OligoG concentrations >2.58% (P<0.05). SEM showed that aerogel-OligoG bio-nanocomposite formulations had a more open 3-dimensional structure, while LP showed film formulations coated with OligoG were significantly smoother than untreated films or films incorporating PEG400 as a plasticizer (P<0.05). CLSM of biofilms grown on films incorporating OligoG demonstrated altered biofilm architecture, with reduced biomass and decreased cell-viability. The OligoG-CNF formulations as aerogels or films both inhibited pyocyanin production (P<0.05). These novel CNF formulations or bio-nanocomposites were able to modify bacterial growth, biofilm development and virulence factor production in vitro. These data support the potential of OligoG and CNF bio-nanocomposites for use in biomedical applications where prevention of infection or biofilm growth is required
Cellular injury and neuroinflammation in children with chronic intractable epilepsy
<p>Abstract</p> <p>Objective</p> <p>To elucidate the presence and potential involvement of brain inflammation and cell death in neurological morbidity and intractable seizures in childhood epilepsy, we quantified cell death, astrocyte proliferation, microglial activation and cytokine release in brain tissue from patients who underwent epilepsy surgery.</p> <p>Methods</p> <p>Cortical tissue was collected from thirteen patients with intractable epilepsy due to focal cortical dysplasia (6), encephalomalacia (5), Rasmussen's encephalitis (1) or mesial temporal lobe epilepsy (1). Sections were processed for immunohistochemistry using markers for neuron, astrocyte, microglia or cellular injury. Cytokine assay was performed on frozen cortices. Controls were autopsy brains from eight patients without history of neurological diseases.</p> <p>Results</p> <p>Marked activation of microglia and astrocytes and diffuse cell death were observed in epileptogenic tissue. Numerous fibrillary astrocytes and their processes covered the entire cortex and converged on to blood vessels, neurons and microglia. An overwhelming number of neurons and astrocytes showed DNA fragmentation and its magnitude significantly correlated with seizure frequency. Majority of our patients with abundant cell death in the cortex have mental retardation. IL-1beta, IL-8, IL-12p70 and MIP-1beta were significantly increased in the epileptogenic cortex; IL-6 and MCP-1 were significantly higher in patients with family history of epilepsy.</p> <p>Conclusions</p> <p>Our results suggest that active neuroinflammation and marked cellular injury occur in pediatric epilepsy and may play a common pathogenic role or consequences in childhood epilepsy of diverse etiologies. Our findings support the concept that immunomodulation targeting activated microglia and astrocytes may be a novel therapeutic strategy to reduce neurological morbidity and prevent intractable epilepsy.</p
Extensive release of methane from Arctic seabed west of Svalbard during summer 2014 does not influence the atmosphere
© 2016. American Geophysical Union. All Rights Reserved. We find that summer methane (CH4) release from seabed sediments west of Svalbard substantially increases CH4 concentrations in the ocean but has limited influence on the atmospheric CH4 levels. Our conclusion stems from complementary measurements at the seafloor, in the ocean, and in the atmosphere from land-based, ship and aircraft platforms during a summer campaign in 2014. We detected high concentrations of dissolved CH4 in the ocean above the seafloor with a sharp decrease above the pycnocline. Model approaches taking potential CH4 emissions from both dissolved and bubble-released CH4 from a larger region into account reveal a maximum flux compatible with the observed atmospheric CH4 mixing ratios of 2.4-3.8 nmol m-2 s-1. This is too low to have an impact on the atmospheric summer CH4 budget in the year 2014. Long-term ocean observatories may shed light on the complex variations of Arctic CH4 cycles throughout the year.The project MOCA- Methane Emissions from the Arctic OCean to the Atmosphere: Present and Future Climate Effects is funded by the Research Council of Norway, grant no.225814 CAGE – Centre for Arctic Gas Hydrate, Environment and Climate research work was supported by the Research Council of Norway through its Centres of Excellence funding scheme grant no. 223259. Nordic Center of Excellence eSTICC (eScience Tool for Investigating Climate Change in northern high latitudes) funded by Nordforsk, grant no. 57001
Elgvandringer i grenseland med følger for skogbruk, jakt og rovdyr
Forvaltning av elg i områder med en delvis trekkende elgbestand byr på utfordringer, fordi kostnadene i form av beiteskader på skogen og goder i form av elgjakt ofte berører forskjellige grunneiere. Dette blir ytterligere komplisert når elgtrekket går på tvers av forvaltningsinndelinger eller til og med over riksgrensen. GRENSEVILT har studert samspillet mellom elg, ulv, skogbruk og jakt i nordre Finnskogen, et stort barskogsområde som er delt av riksgrensen. For å berenge størrelsenpå elgbestanden og beskrive den romlige fordelingen av elg for vintrene 2019/20 og 2020/21, samt somrene 2020 og 2021,har vi gjennomført elgmøkktellinger over et areal på mer enn 3500 km2. Vi ønsket også å studere hvordan elgtrekket påvirker ulvens områdebruk, beitepå furu, og jaktuttaket. Derfor har vived hjelp av GPS-halsbånd analysert områdebruken til fire ulveflokker i samme område. Dessuten gjennomførte vi på våren 2021 en stor beitetakst som kombinerte den norke Solbraa-og den svenske Äbin-metoden. Til slutt har vi sammenstilt jaktdata fra norske vald og svenske älgjaktområder for jaktårene 2019/20 og 2020/21.Vi beregnet elgens tetthet for tidsserien vinter 2019/20, sommer 2020, vinter 2020/21, og sommer 2021 til henholdsvis 1,18, 1,37, 1,01, og 1,70dyr/km2. Om sommeren var elgen noksåjevnt fordelt over hele studieområdet, og om vinteren stod elgen mer konsentrert i de snøfattige områdene, mens det var lite elgi de nordlige, snørike områdene. Til tross for at elgens fordeling endret seg mellom sommer og vinter, opprettholdt ulveflokkene de samme revirgrensene gjennom hele året. Derimot tilpasset de sine aktivitetsområder innenfor revirgrensene til endringen i elgfordelingen. Elgens vinterkonsentrasjonsområder var kjennetegnet ved et større beitetrykk på furu. Skader på produksjontrær var mest hyppig langs dalbunnen og i områder med mye lauvkratt, men vi fant ikke noe tydelig sammenheng mellom skadegrad og elgens vinterfordeling. Elgens effekt på skogbruk målt med den norske Solbraa-metoden viste at beitegraden på furu var stort sett liten. Den svenske Äbin-metoden tegnet et helt motsatt bilde, og bedømmetskadegraden på de samme prøveflatenesomsvært alvorlig. Jaktuttaket i jaktområdene gjenspeilet fordelingen av elg sommerstid i Norge, men ikke i Sverige, der det ble skutt mest elg i områdene med lavest sommertetthet. De hardest beskattede jaktområdene i Sverige hadde en lavere elgtetthet vinteren etter jakt. Vi fant ikke noensammenheng mellom beite-eller skadegrad på furu og jaktuttak i jaktområdene. I den østlige delen av studieområdet som har et stort innslag av trekkelg som oppholder seg på norsk side på sommeren og under jakta, men trekker til Sverige når snøen hoper seg opp lenger nord, var det en tydelig mismatch i forvaltningen av elg mellom de to landene. Mens man i Sverige satset på et høyt jaktuttak for å få bukt med beiteskader,og i tillegg beskattet trekkelg ved januarjakt,sparte man på avskytingen på norsk side fordi beitegraden ikke var bekymringverdigog elgens sommerbestand også ble utsatt for ulvens uttak i tillegg til vinterjakt på svensk side .Vi foreslår en bedre samordning av elgforvaltningen på tvers av riksgrensen. Det krever dialog og samarbeid mellom rettighetshaverne. Et felles elgforvaltningsområde som strekker seg over grensen og dekker trekkelgens helårsområde hadde gjort et slikt samarbeid enklere. Dessuten foreslår vi en samordning av beitetakstmetoden og en felles trafikklysmodell som baserer seg på tetthet av uskadde produksjonstrær heller enn beite-eller skadegraden
Functional biogeography of vertebrate scavengers drives carcass removal across biomes
Resumen del trabajo presentado en el XVI Congreso Nacional de la AEET 2023: la ecología en una biosfera humanizada, celebrado en Almería entre el 16 y el 20 de octubre de 2023.Vertebrate scavengers play a crucial role in food web stability and cycling of organic matter and nutrients. However, the global factors that influence their functional biogeography and impact on ecosystem functioning at regional and local levels remain poorly understood. We aim to address this challenge by analyzing a global dataset covering 49 regions in all inhabited continents, including information on 1,847 locally monitored carcasses and 204 vertebrate scavenger species along with their functional traits. We investigate the importance of biogeographical (spatial), environmental and anthropogenic factors in structuring vertebrate scavengers¿ functional trait composition, diversity and abundance. Additionally, we investigate how these biodiversity attributes affect carcass removal at regional and local scales. Our results show that the functional trait composition of assemblages across studied regions was primarily explained by latitude and lon¬gitude, suggesting a strong biogeographical signature. In addition, while functional richness remained unexplained, scavenger abundance responded to both environmental and spatial factors. Further, we found that carcass removal was mainly driven by functional composition, but with the relative importance of particular functional traits varying from local to regional scales. At the local scale, carcass removal was positively related to large carnivorous species with large home ranges, while at the regional scale, carcass removal was better explained by the presence of vultures, other raptors and diurnal birds. Our study provides a better understanding of the factors controlling the func¬tional biogeography of terrestrial vertebrates and their role in maintaining essential ecological functions and services.Peer reviewe
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