Mountain forest areas are key for providing a wide range of ecosystem services and are hot spots for land use change processes, in particular, increase in forest cover at the expense of mountain pastures and meadows. Mountain forest systems in eastern and western Europe have likely similar future socio-economic situations but significantly different socio-economic history. Using a scenario-based land use modelling approach (Dyna-CLUE framework) we model three scenarios (trend, liberalisation and self-sufficiency) of future land use in the Polish Carpathians and the Swiss Alps, focussing on forest cover change. We find that forest cover increase can be expected to continue in European mountainous regions under all likely scenarios, limited only by relatively strict policy interventions. Biophysical factors, rather than socio-economic ones, are key for defining the suitability for, and therefore likely locations of future forest cover, but land use legacy plays a very important role in the spatial patterns of future forest cover, particularly in eastern Europe.
During application of agrochemicals spray droplets can drift beyond the intended target to non-target receptors, including water, plants and animals. Factors affecting this spray drift include mode of application, droplet size, which can be modified by the nozzle types, formulation adjuvants, wind direction, wind speed, air stability, relative humidity, temperature and height of released spray relative to the crop canopy. The rate of fall of spray droplets depends upon the size of the droplets but is modified by entrainment in a mobile air mass and is also influenced by the rate of evaporation of the liquid constituting the aerosol. The longer the aerosol remains in the air before falling to the ground (or alternatively striking an object above ground) the greater the opportunity for it to be carried away from its intended target. In general, all size classes of droplets are capable of movement off target, but the smallest are likely to move the farthest before depositing on the ground or a non-target receptor. It is not possible to avoid spray drift completely but it can be minimized by using best-management practices. These include using appropriate nozzle types, shields, spray pressure, volumes per area sprayed, tractor speed and only spraying when climatic conditions are suitable. Field layout can also influence spray drift, whilst crop-free and spray-free buffer zones and windbreak crops can also have a mitigating effect. Various models are available to estimate the environmental exposure from spray drift at the time of application. 相似文献
The genomes of complex organisms, including the human genome, are highly structured. This structure takes the form of segmental
patterns of variation in various properties and may be caused by the division of genomes into regions of distinct function,
by the contingent evolutionary processes that gave rise to genomes, or by a combination of both. Whatever the cause, identifying
the change-points between segments is potentially important, as a means of discovering the functional components of a genome,
understanding the evolutionary processes involved, and fully describing genomic architecture. One property of genomes that
is known to display a segmental pattern of variation is GC content. The GC content of a portion of DNA is the proportion of
GC pairs that it contains. Sharp changes in GC content can be observed in human and other genomes. Such change-points may
be the boundaries of functional elements or may play a structural role. We model genome sequences as a multiple change-point
process, that is, a process in which sequential data are separated into segments by an unknown number of change-points, with
each segment supposed to have been generated by a different process. We consider a Sequential Importance Sampling approach
to change-point modeling using Monte Carlo simulation to find estimates of change-points as well as parameters of the process
on each segment. Numerical experiments illustrate the effectiveness of the approach. We obtain estimates for the locations
of change-points in artificially generated sequences and compare the accuracy of these estimates to those obtained via Markov
chain Monte Carlo and a well-known method, IsoFinder. We also provide examples with real data sets to illustrate the usefulness
of this method. 相似文献
Pteris vittata is known to hyperaccumulate As but the mechanism is poorly understood. We found an increase of As concentration with increasing soil solution As concentrations, but P application had no impact, although plant P concentrations responded to different rates of P supply. As in fronds was dominantly (82–89%) present in the form of AsIII. In roots we detected 45% as AsIII which is higher than reported in previous studies and supports substantial As-reduction to take place in roots. We detected PC2/3GS–AsIII, PC2–GS–AsIII and (PC2)2–AsIII in increasing amounts with application of As. The total amount of PC was in the range reported previously and far too small to assign a significant role in As detoxification to PCs. The close correlation between S and As in fronds and the lack of data on sulphur uptake and metabolism indicates the need for a detailed investigation on sulphur nutritional status and As metabolism in P. vittata. 相似文献
DNA barcoding—sequencing a standard region of the mitochondrial cytochrome c oxidase 1 gene (COI)—promises a rapid, accurate means of identifying animals to a species level. This study establishes that
sequence variability in the barcode region permits discrimination of 98% of 201 fish species from the Canadian Pacific. The
average sequence variation within species was 0.25%, while the average distance separating species within genera was 3.75%.
The latter value was considerably lower than values reported in other studies, reflecting the dominance of the Canadian fauna
by members of the young and highly diverse genus Sebastes. Although most sebastids possessed distinctive COI sequences, four species did not. As a partial offset to these cases, the
barcode records indicated the presence of a new, broadly distributed species of Paraliparis and the possibility that Paraliparis pectoralis is actually a species pair. The present study shows that most fish species in Pacific Canadian waters correspond to a single,
tightly cohesive array of barcode sequences that are distinct from those of any other species, but also highlights some taxonomic
issues that need further investigation. 相似文献
The only available data set on the catches of global fisheries are the official landings reported annually by the Food and
Agriculture Organization of the United Nations (FAO). Attempts to detect and interpret trends in these data have been criticized
as being both technically and conceptually flawed. Here, we explore and refute these claims. We show explicitly that trends
in catch data are not an artifact of the applied method and are consistent with trends in biomass data of fully assessed stocks.
We also show that, while comprehensive stock assessments are the preferred method for evaluating single stocks, they are a
biased subsample of the stocks in a given area, strongly underestimating the percentage of collapsed stocks. We concur with
a recent assessment-based analysis by FAO that the increasing trends in the percentage of overexploited, depleted, and recovering
stocks and the decreasing trends in underexploited and moderately exploited stocks give cause for concern. We show that these
trends are much more pronounced if all available data are considered. 相似文献
Scientific information is not always effectively incorporated into decision-making processes. This phenomenon seems to hold
even when the information is aligned with an articulated need, is generated according to sound scientific procedures, and
is packaged with end-user preferences in mind. We propose that contextual or cultural differences contribute significantly
to the misalignment in communication between those who generate information and those who seek information for improved management
of natural resources. The solution is to cultivate shared understanding, which in turn relies on acknowledgment and sharing
of diverse values and attitudes. This constitutes a difficult challenge in a culturally diverse environment. Whereas cultural
diversity represents wealth in experiences, knowledge and perspectives it can constrain the potential to develop the shared
understandings necessary for effective integration of new information. This article illustrates how a lack of shared understanding
among participants engaged in a resource-management process can produce and perpetuate divergent views of the world, to the
extent that information and knowledge flows are ineffective and scientific information, even when requested, cannot be used
effectively. Four themes were distilled from interviews with management and scientific staff of a natural resource–management
agency in South Africa. The themes are used to illustrate how divergent views embedded in different cultures can discourage
alignment of effort toward a common purpose. The article then presents a sense-making framework to illustrate the potential
for developing shared understandings in a culturally diverse world. 相似文献
The occurrence and fate of residues from the therapeutic use of the non-steroidal anti-inflammatory drug metamizole have been studied in investigations of sewage effluents from a military hospital, municipal sewers and a sewage treatment plant (STP) in Berlin, Germany. The loads of the metabolites aminoantipyrin (AA), 4-acetylaminoantipyrin (AAA) and 4-formyl-aminoantipyrin (FAA), rapidly formed after the application of metamizole, were predicted from pharmacokinetic data and based on the evaluation of extensive data sets of on the administration in hospitals and private households. In parallel, the actual concentrations were measured within three field trials. For the military hospital, the estimated average annual discharges of AA/AAA and FAA were 10.5 and 3.2 kg, respectively. For the STP, annual loads of 333 and 133 kg were determined for AA/AAA and FAA, respectively. During sewage treatment, an average decrease of 26% of the loads was measured for AA/AAA whereas no changes were observed for FAA. Generally, the prediction of the loads resulted in an overestimation of the residue levels compared to those measured in the respective sewers. Thus, modeling of predicted loads or concentrations alone will not be sufficient for a realistic assessment. Concerns for human or other mammals' health are not expected from the occurrence of metamizole residues in the aquatic system measured at concentrations up to 7 microg l(-1) in STP effluents. However, a rest of uncertainty remains as it was not possible to derive a no observed effect level for the induction of rare but potentially fatal toxicological side effects reported for metamizole. 相似文献