Greater focus needed on alien plant impacts in protected areas

Alien plants pose significant threats to protected areas worldwide yet many studies only describe the degree to which these areas have become invaded. Research must move toward a better understanding of alien plant impacts since managers urgently require an appropriate evidence base to prioritize control/eradication targets. We analyze a global database of quantitative studies of alien plant impacts to evaluate existing knowledge of alien plant impacts within and outside protected areas. Although protected areas are a significant focus for quantitative impact studies, the biogeographic emphasis of most research effort does not coincide with the global distribution of protected areas nor the plant species or life-forms recognized to have greatest impacts on ecosystems. While impacts were often as significant within protected areas as outside, only a minority of studies provide any subsequent management recommendations. There is therefore considerable scope to improve the evidence base on alien plant management in protected areas

U-Pb zircon age of Ordovician magmatism in the Albera Massif (Eastern Pyrenees)

New geochronological data from the Albera Massif confirm the presence of an Early - Mid Ordovician igneous event (472 - 465Ma) recorded in the pre-Variscan rocks of the Pyrenees. This event resulted in the emplacement of a large granitic body in the lower part of the pre-Upper Ordovician metasedimentary succession and in the intrusion of a series of metric sized dykes in the middle and upper parts of it. The two types of igneous rocks were gneissified during subsequent Variscan deformation. The geochronological data confirm the occurrence of the gneiss as having derived from an Ordovician intrusive sheet, as in other Pyrenean massifs. The dykes are considered to be the subvolcanic equivalent of the intrusive sheet. The data also provide insight into the age of the metasedimentary series of the massif and enable us to correlate the dated rocks with other gneissic and subvolcanic bodies of the Variscan massifs of the Pyrenees and Iberia

A Multilevel Magnetic Synapse Based on Voltage-Tuneable Magnetism by Nitrogen Ion Migration

Altres ajuts: acords transformatius de la UABAltres ajuts: European Union NextGenerationEU/PRTR (grant CNS2022-135230)Advanced synaptic devices with simultaneous memory and processor capabilities are envisaged as core elements of neuromorphic computing (NC) for low-power artificial intelligence. So far, most synaptic devices are based on resistive memories, where the device resistance is tuned with applied voltage or current. However, the use of electric current in such resistive devices causes significant power dissipation due to Joule heating. Higher energy efficiency has been reported in materials exhibiting voltage control of magnetism (VCM). In particular, voltage-driven ion motion to modulate magnetism (magneto-ionics) is an emerging VCM mechanism that can offer new prospects for low-power implementation of NC. In the present work, voltage-driven nitrogen ion motion is exploited in transition metal nitride (CoFeN) thin films (i.e., nitrogen magneto-ionics) to emulate biological synapses. In the proposed device, distinct multilevel non-volatile magnetic states for analog computing and multi-state storage are realized. Moreover, essential synaptic functionalities of the human brain are successfully simulated. The device exhibits an excellent synapse with a remarkable retention time (≈6 months), high switching ratio and large endurance (≈103), for hardware implementation of NC. This research provides new insight into exploiting magneto-ionic-based synaptic devices for spin-based neuromorphic systems

U-Pb zircon age of Ordovician magmatism in the Albera Massif (Eastern Pyrenees)

New geochronological data from the Albera Massif confirm the presence of an Early – Mid Ordovician igneous event (472 - 465Ma) recorded in the pre-Variscan rocks of the Pyrenees. This event resulted in the emplacement of a large granitic body in the lower part of the pre-Upper Ordovician metasedimentary succession and in the intrusion of a series of metric sized dykes in the middle and upper parts of it. The two types of igneous rocks were gneissified during subsequent Variscan deformation. The geochronological data confirm the occurrence of the gneiss as having derived from an Ordovician intrusive sheet, as in other Pyrenean massifs. The dykes are considered to be the subvolcanic equivalent of the intrusive sheet. The data also provide insight into the age of the metasedimentary series of the massif and enable us to correlate the dated rocks with other gneissic and subvolcanic bodies of the Variscan massifs of the Pyrenees and Iberia

Barking up the wrong tree: Modern northern European dogs fail to explain their origin

<p>Abstract</p> <p>Background</p> <p>Geographic distribution of the genetic diversity in domestic animals, particularly mitochondrial DNA, has often been used to infer centers of domestication. The underlying presumption is that phylogeographic patterns among domesticates were established during, or shortly after the domestication. Human activities are assumed not to have altered the haplogroup frequencies to any great extent. We studied this hypothesis by analyzing 24 mtDNA sequences in ancient Scandinavian dogs. Breeds originating in northern Europe are characterized by having a high frequency of mtDNA sequences belonging to a haplogroup rare in other populations (HgD). This has been suggested to indicate a possible origin of the haplogroup (perhaps even a separate domestication) in central or northern Europe.</p> <p>Results</p> <p>The sequences observed in the ancient samples do not include the haplogroup indicative for northern European breeds (HgD). Instead, several of them correspond to haplogroups that are uncommon in the region today and that are supposed to have Asian origin.</p> <p>Conclusion</p> <p>We find no evidence for local domestication. We conclude that interpretation of the processes responsible for current domestic haplogroup frequencies should be carried out with caution if based only on contemporary data. They do not only tell their own story, but also that of humans.</p

Blurring alien introduction pathways risks losing the focus on invasive species policy

The pathways by which alien species are introduced to new regions fall into six broad classes: deliberate release; escape from captivity; contaminant of a commodity; stowaway on a transport vector; via an infrastructure corridor (without which spread would not be possible) or unaided from other invaded regions (Hulme et al. 2008). However, Gilroy et al. (2016) argue that species dispersing naturally, through the infrastructure corridor or unaided pathway, should be classed as native rather than alien. We contend their proposal is not only unworkable but also unwise

Failure propagation in GMPLS optical rings: CTMC model and performance analysis

Network reliability and resilience has become a key design parameter for network operators and Internet service providers. These often seek ways to have their networks fully operational for at least 99.999% of the time, regardless of the number and type of failures that may occur in their networks. This article presents a continuous-time Markov chain model to characterise the propagation of failures in optical GMPLS rings. Two types of failures are considered depending on whether they affect only the control plane, or both the control and data planes of the node. Additionally, it is assumed that control failures propagate along the ring infecting neighbouring nodes, as stated by the Susceptible-Infected-Disabled (SID) propagation model taken from epidemic-based propagation models. A few numerical examples are performed to demonstrate that the CTMC model provides a set of guidelines for selecting the appropriate repair rates in order to attain specific availability requirements, both in the control plane and the data plane.This work is partially supported by the Spanish Ministry of Science and Innovation project TEC 2009-10724 and by the Generalitat de Catalunya research support programme (SGR-1202). Additionally, the authors would like to thank the support of the T2C2 Spanish project (under code TIN2008-06739-C04-01) and the CAM-UC3M Greencom research grant (under code CCG10-UC3M/TIC-5624) in the development of this work.Publicad

Vanishing native American dog lineages

<p>Abstract</p> <p>Background</p> <p>Dogs were an important element in many native American cultures at the time Europeans arrived. Although previous ancient DNA studies revealed the existence of unique native American mitochondrial sequences, these have not been found in modern dogs, mainly purebred, studied so far.</p> <p>Results</p> <p>We identified many previously undescribed mitochondrial control region sequences in 400 dogs from rural and isolated areas as well as street dogs from across the Americas. However, sequences of native American origin proved to be exceedingly rare, and we estimate that the native population contributed only a minor fraction of the gene pool that constitutes the modern population.</p> <p>Conclusions</p> <p>The high number of previously unidentified haplotypes in our sample suggests that a lot of unsampled genetic variation exists in non-breed dogs. Our results also suggest that the arrival of European colonists to the Americas may have led to an extensive replacement of the native American dog population by the dogs of the invaders.</p