219 research outputs found
Utilization of recycled polypropylene, cellulose and newsprint fibres for production of green composites
This work investigates the feasibility of using the recycled polypropylene (rPP), cellulose (CF) and newsprint (NP) fibres in polyolefin reinforced composites. Recycled PP filled with 40 wt.% of cellulose (rPP/CF) or newsprint (rPP/NP), with the addition of impact modifier (IM) and compatibilizing agent (CA), have been prepared with ex-trusion melting and injection moulding. Melting and crystallization behaviour of plain matrix and composites were measured by differential scanning calorimetry (DSC). Morphological and mechanical properties were also studied using scanning electron microscope (SEM) and tensile testing, respectively. Thermal stability of composites was similar to neat rPP for both types of the filler used. Though, the crystallinity was progressively decreased with the addition of CF or NP. The DSC further revealed an occurrence of the two distinct melting transitions, meaning that the examined materials were not based on pure polypropylene (PP), but are rather blends of high-density polyethylene (HDPE) and PP, what has been confirmed also by the Fourier transform infrared spectroscopy (FTIR). The largest single source of contaminations in recycled PP comes from HDPE since both polymers are identified by a similar density and can be accidentally mixed during the conventional physical separation process. Composites reinforced with CF have shown better mechanical performances than those based on reclaimed NP fibres, what can be attributed to the initial fibre quality. Tensile strength of the composites filled with CF and NP fibres was 36 MPa and 29 MPa, respectively, in disparity to 23 MPa measured for neat rPP. The fibre addition further resulted in substantial increase in Young modulus of the composites. The addition of CF and NP fibres lead to an improved modulus of elasticity by 16 and 47%, respectively. Waste paper in the form of recovered cellulose or reclaimed newsprint fibre can thus meet all the technical requirements to become an alternative to inor-ganic fillers in thermoplastic composites
Biogeophysical impacts of peatland forestation on regional climate changes in Finland
Land cover changes can impact the climate by influencing the surface
energy and water balance. Naturally treeless or sparsely treed peatlands were extensively
drained to stimulate forest growth in Finland over the second half
of 20th century. The aim of this study is to investigate the
biogeophysical effects of peatland forestation on regional climate in
Finland. Two sets of 18-year climate simulations were done with the
regional climate model REMO by using land cover data based on
pre-drainage (1920s) and post-drainage (2000s) Finnish national
forest inventories.
In the most intensive peatland forestation area, located in the middle west of Finland, the results show a warming in April of up to 0.43 K in
monthly-averaged daily mean 2 m air temperature, whereas a slight
cooling from May to October of less than 0.1 K in general is found.
Consequently, snow clearance days over that area
are advanced up to 5 days in the mean of 15 years. No clear
signal is found for precipitation. Through analysing the simulated
temperature and energy balance terms, as well as snow depth over
five selected subregions, a positive feedback induced by peatland
forestation is found between decreased surface albedo and increased
surface air temperature in the snow-melting period. Our modelled
results show good qualitative agreements with the observational
data. In general, decreased surface albedo in the snow-melting period and
increased evapotranspiration in the growing period are the most
important biogeophysical aspects induced by peatland forestation
that cause changes in climate. The results from this study can be further integrally analysed with biogeochemical effects of peatland forestation
to provide background information for adapting future forest management to mitigate climate warming effects. Moreover, they
provide insights about the impacts of projected forestation of tundra at high latitudes due to climate change
Complex evolution and epidemiology of Dobrava-Belgrade hantavirus: definition of genotypes and their characteristics.
Dobrava-Belgrade virus (DOBV) is a human pathogen that has evolved in, and is hosted by, mice of several species of the genus Apodemus. We propose a subdivision of the species Dobrava-Belgrade virus into four related genotypes – Dobrava, Kurkino, Saaremaa, and Sochi – that show characteristic differences in their phylogeny, specific host reservoirs, geographical distribution, and pathogenicity for humans
A new method for estimating carbon dioxide emissions from drained peatland forest soils for the greenhouse gas inventory of Finland
In peatlands drained for forestry, the soil carbon (C) or
carbon dioxide (CO2) balance is affected by both (i)Â higher
heterotrophic CO2-C release from faster decomposing soil organic matter
(SOM) and (ii)Â higher plant litter C input from more vigorously growing
forests. This balance and other greenhouse gas (GHG) sinks and sources in
managed lands are annually reported by national GHG inventories to the
United Nations Climate Change Convention. In this paper, we present a
revised, fully dynamic method for reporting the CO2 balance of drained
peatland forest soils in Finland. Our method can follow temporal changes in
tree biomass growth, tree harvesting and climatic parameters, and it is built
on empirical regression models of SOM decomposition and litter input in
drained peatland forests. All major components of aboveground and
belowground litter input from ground vegetation as well as live trees and trees that died naturally
are included, supplemented by newly acquired turnover rates of woody
plant fine roots. Annual litter input from harvesting residues is calculated
using national statistics of logging and energy use of trees. Leaching,
which also exports dissolved C from drained peatlands, is not included. The
results are reported as time series from 1990–2021 following the practice
in the GHG inventory. Our revised method produces an increasing trend of annual
emissions from 0.2 to 2.1 t CO2 ha−1 yr−1 for the period
1990–2021 in Finland (equal to a trend from 1.4 to 7.9 Mt CO2 yr−1 for the entire 4.3 Mha of drained peatland forests), with a
statistically significant difference between the years 1990 and 2021. Across the
period 1990–2021, annual emissions are on average 1.5 t CO2 ha−1 yr−1 (3.4 Mt CO2 yr−1 for 2.2 Mha area) in warmer southern
Finland and −0.14 t CO2 ha−1 yr−1 (−0.3 Mt CO2 yr−1
for 2.1 Mha area) in cooler northern Finland. When combined with data on the
CO2 sink created by the growing tree stock, in 2021 the drained peatland forest
ecosystems were a source of 1.0 t CO2 ha−1 yr−1 (2.3 Mt CO2 yr−1) in southern Finland and a sink of 1.2 t CO2 ha−1 yr−1 (2.5 Mt CO2 yr−1) in northern Finland. We
compare these results to those produced by the semi-dynamic method used earlier
in the Finnish GHG inventory and discuss the strengths and
vulnerabilities of the new revised method in comparison to more static
emission factors.</p
Building an integrated infrastructure for exploring biodiversity: field collections and archives of mammals and parasites.
Museum specimens play an increasingly important role in predicting the outcomes and revealing the consequences of anthropogenically driven disruption of the biosphere. As ecological communities respond to ongoing environmental change, host-parasite interactions are also altered. This shifting landscape of host-parasite associations creates opportunities for colonization of different hosts and emergence of new pathogens, with implications for wildlife conservation and management, public health, and other societal concerns. Integrated archives that document and preserve mammal specimens along with their communities of associated parasites and ancillary data provide a powerful resource for investigating, anticipating, and mitigating the epidemiological, ecological, and evolutionary impacts of environmental perturbation. Mammalogists who collect and archive mammal specimens have a unique opportunity to expand the scope and impact of their field work by collecting the parasites that are associated with their study organisms. We encourage mammalogists to embrace an integrated and holistic sampling paradigm and advocate for this to become standard practice for museum-based collecting. To this end, we provide a detailed, field-tested protocol to give mammalogists the tools to collect and preserve host and parasite materials that are of high quality and suitable for a range of potential downstream analyses (e.g., genetic, morphological). Finally, we also encourage increased global cooperation across taxonomic disciplines to build an integrated series of baselines and snapshots of the changing biosphere. Los especÃmenes de museo desempeñan un papel cada vez más importante tanto en la descripción de los resultados de la alteración antropogénica de la biosfera como en la predicción de sus consecuencias. Dado que las comunidades ecológicas responden al cambio ambiental, también se alteran las interacciones hospedador-parásito. Este panorama cambiante de asociaciones hospedador-parásito crea oportunidades para la colonización de diferentes hospedadores y para la aparición de nuevos patógenos, con implicancias en la conservación y manejo de la vida silvestre, la salud pública y otras preocupaciones de importancia para la sociedad. Archivos integrados que documentan y preservan especÃmenes de mamÃferos junto con sus comunidades de parásitos y datos asociados, proporcionan un fuerte recurso para investigar, anticipar y mitigar los impactos epidemiológicos, ecológicos y evolutivos de las perturbaciones ambientales. Los mastozoólogos que recolectan y archivan muestras de mamÃferos, tienen una oportunidad única de ampliar el alcance e impacto de su trabajo de campo mediante la recolección de los parásitos que están asociados con los organismos que estudian. Alentamos a los mastozoólogos a adoptar un paradigma de muestreo integrado y holÃstico y abogamos para que esto se convierta en una práctica estándarizada de la obtención de muestras para museos. Con este objetivo, proporcionamos un protocolo detallado y probado en el campo para brindar a los mastozoólogos las herramientas para recolectar y preservar materiales de parásitos y hospedadores de alta calidad y adecuados para una gran variedad de análisis subsecuentes (e.g., genéticos, morfológicos, etc.). Finalmente, también abogamos por una mayor cooperación global entre las diversas disciplinas taxonómicas para construir una serie integrada de lÃneas de base y registros actuales de nuestra cambiante biosfera
Population cycles and outbreaks of small rodents : ten essential questions we still need to solve
Correction: 10.1007/s00442-021-04856-4, Oecologia (2021)Most small rodent populations in the world have fascinating population dynamics. In the northern hemisphere, voles and lemmings tend to show population cycles with regular fluctuations in numbers. In the southern hemisphere, small rodents tend to have large amplitude outbreaks with less regular intervals. In the light of vast research and debate over almost a century, we here discuss the driving forces of these different rodent population dynamics. We highlight ten questions directly related to the various characteristics of relevant populations and ecosystems that still need to be answered. This overview is not intended as a complete list of questions but rather focuses on the most important issues that are essential for understanding the generality of small rodent population dynamics.Peer reviewe
Team sports performance analysed through the lens of social network theory: implications for research and practice
This paper discusses how social network analyses and graph theory can be implemented in team sports performance analyses to evaluate individual (micro) and collective (macro) performance data, and how to use this information for designing practice tasks. Moreover, we briefly outline possible limitations of social network studies and provide suggestions for future research. Instead of cataloguing discrete events or player actions, it has been argued that researchers need to consider the synergistic interpersonal processes emerging between teammates in competitive performance environments. Theoretical assumptions on team coordination prompted the emergence of innovative, theoretically-driven methods for assessing collective team sport behaviours. Here, we contribute to this theoretical and practical debate by conceptualising sports teams as complex social networks. From this perspective, players are viewed as network nodes, connected through relevant information variables (e.g., a ball passing action), sustaining complex patterns of interaction between teammates (e.g., a ball passing network). Specialized tools and metrics related to graph theory could be applied to evaluate structural and topological properties of interpersonal interactions of teammates, complementing more traditional analysis methods. This innovative methodology moves beyond use of common notation analysis methods, providing a richer understanding of the complexity of interpersonal interactions sustaining collective team sports performance. The proposed approach provides practical applications for coaches, performance analysts, practitioners and researchers by establishing social network analyses as a useful approach for capturing the emergent properties of interactions between players in sports teams
Crossing the Interspecies Barrier: Opening the Door to Zoonotic Pathogens
The number of pathogens known to infect humans is ever increasing. Whether such increase reflects improved surveillance and detection or actual emergence of novel pathogens is unclear. Nonetheless, infectious diseases are the second leading cause of human mortality and disability-adjusted life years lost worldwide [1], [2]. On average, three to four new pathogen species are detected in the human population every year [3]. Most of these emerging pathogens originate from nonhuman animal species
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