In this paper, likelihood-based algorithms are explored for linear digital modulation classification. Hybrid likelihood ratio test (HLRT)- and quasi HLRT (QHLRT)- based algorithms are examined, with ...signal amplitude, phase, and noise power as unknown parameters. The algorithm complexity is first investigated, and findings show that the HLRT suffers from very high complexity, whereas the QHLRT provides a reasonable solution. An upper bound on the performance of QHLRT-based algorithms, which employ unbiased and normally distributed non-data aided estimates of the unknown parameters, is proposed. This is referred to as the QHLRT-Upper Bound (QHLRT-UB). Classification of binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK) signals is presented as a case study. The Cramer-Rao Lower Bounds (CRBs) of non-data aided joint estimates of signal amplitude and phase, and noise power are derived for BPSK and QPSK signals, and further employed to obtain the QHLRT-UB. An upper bound on classification performance of any likelihood-based algorithms is also introduced. Method-of-moments (MoM) estimates of the unknown parameters are investigated and used to develop the QHLRT-based algorithm. Classification performance of this algorithm is compared with the upper bounds, as well as with the quasi Log-Likelihood Ratio (qLLR) and fourth-order cumulant based algorithms.
The Natura 2000 network is regarded as one of the conservation success stories in the global effort to protect biodiversity. However, significant challenges remain in Natura 2000 implementation, ...owing to its rapid expansion, and lack of a coherent vision for its future. Scientific research is critical for identifying conservation priorities, setting management goals, and reconciling biodiversity protection and society in the complex political European landscape. Thus, there is an urgent need for a comprehensive evaluation of published Natura 2000 research to highlight prevalent research themes, disciplinary approaches, and spatial entities. We conducted a systematic review of 572 scientific articles and conference proceedings focused on Natura 2000 research, published between 1996 and 2014. We grouped these articles into 'ecological' and 'social and policy' categories. Using a novel application of network analysis of article keywords, we found that Natura 2000 research forms a cohesive small-world network, owing to the emphasis on ecological research (79% of studies, with a strong focus on spatial conservation planning), and the underrepresentation of studies addressing 'social and policy' issues (typically focused on environmental impact assessment, multi-level governance, agri-environment policy, and ecosystem services valuation). 'Ecological' and 'social and policy' research shared only general concepts (e.g., Natura 2000, Habitats Directive) suggesting a disconnection between these disciplines. The UK and the Mediterranean basin countries dominated Natura 2000 research, and there was a weak correlation between number of studies and proportion of national territory protected. Approximately 40% of 'social and policy' research and 26% of 'ecological' studies highlighted negative implications of Natura 2000, while 21% of studies found positive social and biodiversity effects. We emphasize the need for designing inter- and transdisciplinary research in order to promote a social-ecological understanding of Natura 2000, and advance EU conservation policies.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Charged particles can be accelerated to high energies by collisionless shock waves in astrophysical environments, such as supernova remnants. By interacting with the magnetized ambient medium, these ...shocks can transfer energy to particles. Despite increasing efforts in the characterization of these shocks from satellite measurements at Earth’s bow shock as well as powerful numerical simulations, the underlying acceleration mechanism or a combination thereof is still widely debated. Here we show that astrophysically relevant super-critical quasi-perpendicular magnetized collisionless shocks can be produced and characterized in the laboratory. We observe the characteristics of super-criticality in the shock profile as well as the energization of protons picked up from the ambient gas to hundreds of kiloelectronvolts. Kinetic simulations modelling the laboratory experiment identified shock surfing as the proton acceleration mechanism. Our observations not only provide direct evidence of early-stage ion energization by collisionless shocks but also highlight the role played by this particular mechanism in energizing ambient ions to feed further stages of acceleration. Furthermore, our results open the door to future laboratory experiments investigating the possible transition to other mechanisms, when increasing the magnetic field strength, or the effect that induced shock front ripples could have on acceleration processes.Proton acceleration by a super-critical collisionless shock is observed in laboratory experiments, and numerical simulations suggest shock surfing as the underlying acceleration mechanism.
Protected areas are key to meeting biodiversity conservation goals, but direct measures of effectiveness have proven difficult to obtain. We address this challenge by using environmental DNA from ...leech-ingested bloodmeals to estimate spatially-resolved vertebrate occupancies across the 677 km
Ailaoshan reserve in Yunnan, China. From 30,468 leeches collected by 163 park rangers across 172 patrol areas, we identify 86 vertebrate species, including amphibians, mammals, birds and squamates. Multi-species occupancy modelling shows that species richness increases with elevation and distance to reserve edge. Most large mammals (e.g. sambar, black bear, serow, tufted deer) follow this pattern; the exceptions are the three domestic mammal species (cows, sheep, goats) and muntjak deer, which are more common at lower elevations. Vertebrate occupancies are a direct measure of conservation outcomes that can help guide protected-area management and improve the contributions that protected areas make towards global biodiversity goals. Here, we show the feasibility of using invertebrate-derived DNA to estimate spatially-resolved vertebrate occupancies across entire protected areas.
Chronic treatment with oral levodopa is associated with an increased frequency of motor complications in the late stages of Parkinson’s disease (PD). Continuous administration of levodopa–carbidopa ...intestinal gel (LCIG—Duodopa
®
, Abbott Laboratories), which has been available in Romania since 2009, represents an option for treating patients with advanced PD. Our primary objective was to report changes in motor complications after initiation of LCIG therapy. The secondary objectives were as follows: to determine the impact of LCIG therapy on the daily levodopa dose variation before/and after LCIG, to collect patient self-assessments of quality of life (QoL), and to study the overall tolerability and safety of LCIG administration. A retrospective analysis (2009–2013) of LCIG therapy and the experience in nine neurology centers in Romania was performed. The impact of LCIG therapy was evaluated by analyzing changes in motor fluctuations, dyskinesia and the patients’ QoL after initiating therapy. The safety of LCIG therapy was estimated by noting agent-related adverse events (AEs) and medical device-related AEs. In the 113 patients included, we observed a significant improvement in PD symptoms after initiation of LCIG therapy. The “on” period increased, with a mean value of 6.14 h, and the dyskinesia period was reduced, with a mean value of 29.4 %. The quantified non-motor symptoms subsided. The patients exhibited significant improvements in QoL scores. There were few AEs and few cases of LCIG therapy discontinuation. LCIG is an important and available therapeutic option for managing patients with advanced PD.
Conservation of forest amphibians is dependent on finding the right balance between management for timber production and meeting species' habitat requirements. For many pond-breeding amphibians, ...successful dispersal of the juvenile stage is essential for long-term population persistence. We investigated the influence of timber-harvesting practices on the movements of juvenile wood frogs (
Lithobates sylvaticus
). We used a chronosequence of stands produced by clear-cutting to evaluate how stand age affects habitat permeability to movements. We conducted experimental releases of juveniles in 2008 (
n
== 350) and 2009 (
n
== 528) in unidirectional runways in four treatments: mature forest, recent clearcut, 11-year-old, and 20-year-old regeneration. The runways were 50 ×× 2.5-m enclosures extending into each treatment, perpendicular to a distinct edge, with four tracking stations at 10, 20, 30, and 40 m from the edge. We recorded the number of animals reaching each tracking station, and the proportion of animals changing their direction of movement at each distance. We found that the mature forest was 3.1 and 3.7 times more permeable than the 11-year-old regeneration and the recent clearcut, respectively. Animals actively avoided open-canopy habitats and sharp edges; significantly more animals returned toward the closed-canopy forest at 0 m and 10 m in the less permeable treatments. There were no significant differences in habitat permeability between the mature forest and the 20-year-old regeneration. Our study is the first to directly assess habitat permeability to juvenile amphibian movement in relation to various forestry practices. We argue that habitat permeability at this scale is largely driven by the behavior of animals in relation to habitat disturbance and that caution needs to be used when using spatial modeling and expert-derived permeability values to assess connectivity of amphibian populations. The effects of clear-cutting on the migratory success of juvenile
L. sylvaticus
are long-lasting. Forestry practices that involve canopy removal and conversion of natural forest to conifer plantations may affect regional population viability by hindering successful dispersal.
The European Union strives to increase protected areas of the EU terrestrial surface to 30% by year 2030, of which one third should be strictly protected. Designation of the Natura 2000 network, the ...backbone of nature protection in the EU, was mostly an expert-opinion process with little systematic conservation planning. The designation of the Natura 2000 network in Romania followed the same non-systematic approach, resulting in a suboptimal representation of invertebrates and plants. To help identify areas with very high biodiversity without repeating past planning missteps, we present a reproducible example of spatial prioritization using Romania's current terrestrial Natura 2000 network and coarse-scale terrestrial species occurrence.
We used 371 terrestrial Natura 2000 Sites of Community Importance (Natura 2000 SCI), designated to protect 164 terrestrial species listed under Annex II of Habitats Directive in Romania in our spatial prioritization analyses (marine Natura 2000 sites and species were excluded). Species occurrences in terrestrial Natura 2000 sites were aggregated at a Universal Traverse Mercator spatial resolution of 1 km
. To identify priority terrestrial Natura 2000 sites for species conservation, and to explore if the Romanian Natura 2000 network sufficiently represents species included in Annex II of Habitats Directive, we used Zonation v4, a decision support software tool for spatial conservation planning. We carried out the analyses nationwide (all Natura 2000 sites) as well as separately for each biogeographic region (i.e., Alpine, Continental, Pannonian, Steppic and Black Sea).
The results of spatial prioritization of terrestrial Natura 2000 vary greatly by planning scenario. The performance of national-level planning of top priorities is minimal. On average, when 33% of the landscape of Natura 2000 sites is protected, only 20% of the distribution of species listed in Annex II of Habitats Directive are protected. As a consequence, the representation of species by priority terrestrial Natura 2000 sites is lessened when compared to the initial set of species. When planning by taxonomic group, the top-priority areas include only 10% of invertebrate distribution in Natura 2000. When selecting top-priority areas by biogeographical region, there are significantly fewer gap species than in the national level and by taxa scenarios; thusly, the scenario outperforms the national-level prioritization. The designation of strictly protected areas as required by the EU Biodiversity Strategy for 2030 should be followed by setting clear objectives, including a good representation of species and habitats at the biogeographical region level.
Romania’s protected areas network currently covers 19.29% of the national territory, a significant increase from the 4.1% protected prior to 1989. The increase occurred over the past 20
years with ...the creation of 27 National and Natural Parks, and recently of 382 protected areas as part of the pan-European Natura 2000 network. Considering the recent increase in number and area of protected lands, we investigated two core topics critical to achieving conservation goals: (1) conservation value and (2) resources for conservation. The newly created Natura 2000 sites overlapped 96.19% of the existing protected areas network, generating up to three different protection statuses for some sites. Conservation goals were often unclear, as the focus switched to protecting species and habitats of European-level concern. Despite the fivefold increase in protected area, many ecoregions were poorly represented in the new system. Planning for conservation neither involved the local communities nor utilized principles for spatial prioritization. Over 80% of the species of European conservation concern were included in at least one protected area, but plants and invertebrates were underrepresented. Administrative bodies were generally under-staffed and poorly financed, conditions that were reflected in a poor enforcement and implementation of conservation goals. Overall, Romania shares many conservation concerns with other Eastern and Central European countries. A regional approach to conserving biodiversity based on spatial prioritization, rigorous scientific documentation, and social acceptance is needed for the Natura 2000 network to achieve its goals.
Wolf-Hirschhorn syndrome is a rare condition caused by terminal deletions, of variable size, in the short arm of chromosome 4. The syndrome displays the combination of typical morphological facial ...variations, intellectual disability, language delay, and various malformations. This report describes the clinical aspect and developmental evolution of a male patient with Wolf-Hirschhorn syndrome, from infancy to adolescence. The patient was first examined and diagnosed at 11 months, with follow-up at the ages of 4 and 16.
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