IVA using complex multivariate GGD: application to fMRI analysis

Multidimensional Systems and Signal Processing - Examples of complex-valued random phenomena in science and engineering are abound, and joint blind source separation (JBSS) provides an effective...     

Agricultural pesticides threaten the ecological integrity of northern prairie wetlands.

The northern Great Plains of North America has millions of small wetlands, and these are often dispersed through cultivated fields. We investigated relationship between pesticide occurrence and precipitation in selected wetlands in a 30.4 x 10(4) km2 area of the Great Plains with relatively uniform farming practices and 1,777,600 wetlands (southern Saskatchewan, Canada). By early July after pesticides have been applied to crops, the mean number of pesticides detected in wetlands ranged from 1.8 in regions with little precipitation (< 21 mm rain during the previous 15 days) to 3.2 in regions under higher rainfall (> 90 mm). The proportion of wetlands in which at least one pesticide exceeded Canadian guidelines for the protection of aquatic life increased from 0% to 60% over this same precipitation range. The maximum number of pesticides detected in a single wetland was six. Concentration of lindane in wetlands increased with increasing precipitation. Using geographic information on rainfall, wetland densities, area seeded to crops, and region specific relationships between pesticides and precipitation, we estimated the number of wetlands in Saskatchewan with elevated levels of pesticides. In early July, during 3 of the 6 years, the number of wetlands subjected to pesticide levels that exceeded guidelines for the protection of aquatic life was significant, ranging from 152,000 to 424,000 wetlands or 9-24%, respectively, of the total. Lindane and triallate exceeded the guidelines most frequently.     

A microstructure and mechanical property investigation on thermally sprayed nanostructured ceramic coatings before and after a sintering treatment

Coatings have been deposited by air plasma spraying of alumina powders in the form of conventional particles (C), nanostructured agglomerates (N) and sintered–nanostructured agglomerates (S). Sintering alleviated the stresses introduced in the nanopowder by the manufacturing process (high energy ball milling). The coating porosity is a direct consequence of the powder melting degree, which is related to the feedstock porosity. The mechanical performance of the coatings is also closely associated with the powder melting degree. The N coatings present the highest surface roughness due to the lowest melting degree. The slightly higher hardness values of the N and S coatings, as compared to the C coatings, are attributed to the higher percentages of α-Al₂O₃ and the presence of nanostructure. The S coatings exhibit superior adhesion strength, relative fracture toughness and wear resistance, due to sintering consequences (intraparticle cohesion, strain relief, tough splat boundaries), random dispersion of coherent nanozones and stress dissipation at nanograin boundaries.     

Speed Scaling for Maximum Lateness

We consider the power-aware problem of scheduling non-preemptively a set of jobs on a single speed-scalable processor so as to minimize the maximum lateness, under a given budget of energy. In the offline setting, our main contribution is a combinatorial polynomial time algorithm for the case in which the jobs have common release dates. In the presence of arbitrary release dates, we show that the problem becomes strongly \(\mathcal {N}\mathcal {P}\)-hard. Moreover, we show that there is no O(1)-competitive deterministic algorithm for the online setting in which the jobs arrive over time. Then, we turn our attention to an aggregated variant of the problem, where the objective is to find a schedule minimizing a linear combination of maximum lateness and energy. As we show, our results for the budget variant can be adapted to derive a similar polynomial time algorithm and an \(\mathcal {N}\mathcal {P}\)-hardness proof for the aggregated variant in the offline setting, with common and arbitrary release dates respectively. More interestingly, for the online case, we propose a 2-competitive algorithm.     

A trustworthy multimedia participatory platform for cultural heritage management in smart city environments

Multimedia Tools and Applications - Cultural heritage applications within smart city environments are becoming extremely popular to public authorities. The success of such applications lies on...     

An automated two-step NDVI-based method for the production of low-cost historical burned area map records over large areas

The recognition and understanding of long-term fire-related processes and patterns, such as the possible connection between the increased frequency of wildfires and global warming, requires the study of historical data records. In this study, a methodology was proposed for the automated production of long historical burned area map records over large-scale regions. The methodology was based on remotely sensed, high temporal resolution, normalized difference vegetation index (NDVI) data that could be easily acquired at medium or low spatial resolution. The proposed methodology was used to map the burned areas of the wildfires that occurred over the Peloponnese peninsula, Greece, during the summer of 2007. The method was built upon the NDVI data collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) and Système Pour l’Observation de la Terre (SPOT)-VEGETATION. The higher spatial resolution data of MODIS resulted in higher burned area user accuracy (91.10%) and kappa (0.85) values than the respective ones for VEGETATION (79.29% and 0.77). The majority of classification errors were located along the perimeter of the burned areas and were mainly attributed to spatial resolution limitations of the remotely sensed data. The commission errors located away from the fire perimeter were primarily attributed to topographically shaded areas and land-cover types spectrally similar to burned areas. The omission errors resulted primarily from the small size and elongated shape of remote burned areas. Owing to their geometry, they have a high proportion of mixed pixels, whose spectral properties failed to meet the strict set of criteria for core fire pixels. The benefits of the proposed methodology are maximized when applied to data of the highest available spatial resolution, such as those collected by MODIS and the Project for On-Board Autonomy – Vegetation (PROBA-V) and when land-cover types spectrally similar to burned areas are masked prior to its application.     

The response to rapid infusion of fentanyl in the human brain measured using pulsed arterial spin labelling

Objective

We evaluated the sensitivity of pulsed Arterial Spin Labelling (pASL) for the detection of changes in regional cerebral blood perfusion (CBP) during and after intra-venous (i.v.) infusion of an opioid agonist (fentanyl) and an opioid antagonist (naloxone).

Materials and methods

Twenty-three subjects were scanned four times, receiving i.v. infusion of fentanyl, naloxone, placebo and a second fentanyl administration, in four separate scanning sessions in randomised order. End-tidal CO₂, respiration rate and heart rate were recorded continuously throughout each scan. pASL time series were collected using single shot EPI for 15?min (including 5?min of baseline prior to infusion).

Results

Significant increases in CBP were detected during and after administration of fentanyl, (when compared to placebo and naloxone), in most areas of high concentration of mu-opioid receptors (thalamus, lingual gyrus, para-hippocampal gyrus, and insula); near-significant increases were also observed in the insula. No increases in perfusion were observed during or after naloxone infusion. No correlation was found between regional rCBF changes and end-tidal CO₂, respiration rate or heart rate. Good reliability was found between the first and second fentanyl sessions but the regions of high reliability did not overlap completely with those of highest perfusion change.

Conclusion

pASL is a suitable method for examining rapid, dynamic effects of opioid administration on brain physiology.