82 research outputs found

    Owls (Strigiformes) in Parque Nacional Peneda-Gerês (PNPG) – Portugal

    Get PDF
    Owls (Strigiformes) are particularly difficult to study and the existing information is still scarce. In PNPG area there are records of the seven species present in Portugal; the Long-eared Owl and the Short-eared Owl are here occasional species. This work aims to determine the distribution, density and abundance of Strigiformes in PNPG (Northwest of Portugal). Between December 2007 and June 2008, 106 passive hearing point counts of 15 minutes each were done in the centre of each of 106 squares (2x2 km). Distribution maps for each species were obtained. Therefore, we recorded a total of 98 contacts for Tawny Owl and 67 contacts for Scops Owl. We also obtained 7 contacts of Little Owl, 2 contacts of Barn Owl and one of Eagle Owl. The habitat selection by Scops Owl and Tawny Owl was also studied. Scops Owls seems to avoid low shrub and preferred forested areas. Tawny Owls also avoid low shrub areas, preferring forested areas, and were found in urban areas. The populations of these two species in PNPG show a considerable expansion, while the other ones reveal a marked decline regarding the previous situation. The implementation of monitoring and conservation measures is suggested to stop the decline of these three species

    Trends in Mesenchymal Stem Cells\u27 Applications for Skeletal Muscle Repair and Regeneration

    Get PDF
    Skeletal muscle injuries are quite frequent in traumatic scenarios, such as war injuries or road- or work-related accidents. The skeletal muscle has good regenerative ability, but the extent or recurrence of muscle injury might impair complete structural and functional recovery. Severe tissue loss overwhelms skeletal muscle´s intrinsic regenerative capabilities and culminates in the development of noncontractile fibrous tissue scar. Conservative RICE -based and surgical treatments show limited efficacy in terms of improving these severe cases outcomes, pressing the need for new approaches on skeletal muscle’s therapy. Since the first suggestions of the potential of mesenchymal stem cells for regenerative medicine and tissue engineering, many applications have been explored for a variety of tissues and diseases, including the skeletal muscle, which is the focus of this literature review

    Heuristic Segmentation of a Nonstationary Time Series

    Full text link
    Many phenomena, both natural and human-influenced, give rise to signals whose statistical properties change under time translation, i.e., are nonstationary. For some practical purposes, a nonstationary time series can be seen as a concatenation of stationary segments. Using a segmentation algorithm, it has been reported that for heart beat data and Internet traffic fluctuations--the distribution of durations of these stationary segments decays with a power law tail. A potential technical difficulty that has not been thoroughly investigated is that a nonstationary time series with a (scale-free) power law distribution of stationary segments is harder to segment than other nonstationary time series because of the wider range of possible segment sizes. Here, we investigate the validity of a heuristic segmentation algorithm recently proposed by Bernaola-Galvan et al. by systematically analyzing surrogate time series with different statistical properties. We find that if a given nonstationary time series has stationary periods whose size is distributed as a power law, the algorithm can split the time series into a set of stationary segments with the correct statistical properties. We also find that the estimated power law exponent of the distribution of stationary-segment sizes is affected by (i) the minimum segment size, and (ii) the ratio of the standard deviation of the mean values of the segments, and the standard deviation of the fluctuations within a segment. Furthermore, we determine that the performance of the algorithm is generally not affected by uncorrelated noise spikes or by weak long-range temporal correlations of the fluctuations within segments.Comment: 23 pages, 14 figure

    Undamning the Douro river catchment: a stepwise approach for prioritizing dam removal

    Get PDF
    Dams provide water supply, flood protection, and hydropower generation benefits, but also harm native species by altering the natural flow regime, and degrading the aquatic and riparian habitats. In the present study, which comprised the Douro River basin located in the North of Portugal, the cost-benefit assessment of dams was based upon a balance between the touristic benefits of a dammed Douro, and the ecological benefits of less fragmented Douro sub-catchments. Focused on four sub-catchments (Sabor, Tâmega, Côa and Corgo), a probabilistic stream connectivity model was developed and implemented to recommend priorities for dam removal, where this action could significantly improve the movement of potadromous fish species along the local streams. The proposed model accounts for fish movement across the dam or weir (permeability), which is a novel issue in connectivity models. However, before any final recommendation on the fate of a dam or weir, the connectivity results will be balanced with other important socio-economic interests. While implementing the connectivity model, an inventory of barriers (dams and weirs) was accomplished through an observation of satellite images. Besides identification and location of any obstacles, the inventory comprised the compilation of data on surrounding land use, reservoir water use, characteristics of the riparian gallery, and permeability conditions for fish, among others. All this information was stored in a geospatial dataset that also included geographical information on the sub-catchment drainage network. The linear (drainage network) and point (barriers) source data were processed in a computer program that provided or returned numbers for inter-barrier stream lengths (habitat), and the barrier permeability. These numbers were finally used in the same computer program to calculate a habitat connector index, and a link improvement index, used to prioritize dam removal based upon structural connectivity criteria. The results showed that habitat patch connectivity in the Sabor, Tâmega and Côa sub-catchments is not dramatically affected by the installed obstacles, because most link improvement values were generally low. For the opposite reason, in the Corgo sub-catchment, obstacles may constitute a relatively higher limitation to connectivity, and in this case the removal of eight obstacles could significantly improve this connectivity. Using the probabilistic model of structural connectivity, it was possible to elaborate a preliminary selection of dams/weirs that critically limit stream connectivity, and that will be the focus of field hydraulic characterization to precisely determine fish movement along the associated river stretches. Future work will also include the implementation of a multi-criteria decision support system for dam removal or mitigation of the critical structures, as well to define exclusion areas for additional obstaclesinfo:eu-repo/semantics/publishedVersio

    Essential oil composition and antioxidant and antimicrobial properties of Campomanesia pubescens O. Berg, Native of Brazilian Cerrado

    Get PDF
    In this study, the essential oil composition, total contents of phenolics and proanthocyanidins, antioxidant and antimicrobial activities from different plant parts (root, stem, leaf and fruit) of Campomanesia pubescens (DC) O. Berg from Brazilian Cerrado are reported. The root essential oil is distinguished from others by having only one representative of monoterpenes (alpha-terpenylacetate). The aerial parts of C. pubescens are rich in volatile terpenes, as expected, especially in fruits whose essential oil contained approximately 80 % of monoterpenes. The essential oils showed antimicrobial activity against oral pathogens. The root essential oil showed the strongest inhibition against Fusobacterium nucleatum (ATCC 25586). The leaf extract presented the highest concentration of phenolic and proanthocyanidins compounds. The lowest concentration necessary for inhibition of DPPH to 50 % ranged between 6.6 ± 1.6 and 56.6 ± 2.3 μg/mL. The leaf extract exhibited the highest inhibition, close to BHT.Colegio de Farmacéuticos de la Provincia de Buenos Aire
    corecore