A spatiotemporal analysis of gait freezing and the impact of pedunculopontine nucleus stimulation

Gait freezing is an episodic arrest of locomotion due to an inability to take normal steps. Pedunculopontine nucleus stimulation is an emerging therapy proposed to improve gait freezing, even where refractory to medication. However, the efficacy and precise effects of pedunculopontine nucleus stimulation on Parkinsonian gait disturbance are not established. The clinical application of this new therapy is controversial and it is unknown if bilateral stimulation is more effective than unilateral. Here, in a double-blinded study using objective spatiotemporal gait analysis, we assessed the impact of unilateral and bilateral pedunculopontine nucleus stimulation on triggered episodes of gait freezing and on background deficits of unconstrained gait in Parkinson’s disease. Under experimental conditions, while OFF medication, Parkinsonian patients with severe gait freezing implanted with pedunculopontine nucleus stimulators below the pontomesencephalic junction were assessed during three conditions; off stimulation, unilateral stimulation and bilateral stimulation. Results were compared to Parkinsonian patients without gait freezing matched for disease severity and healthy controls. Pedunculopontine nucleus stimulation improved objective measures of gait freezing, with bilateral stimulation more effective than unilateral. During unconstrained walking, Parkinsonian patients who experience gait freezing had reduced step length and increased step length variability compared to patients without gait freezing; however, these deficits were unchanged by pedunculopontine nucleus stimulation. Chronic pedunculopontine nucleus stimulation improved Freezing of Gait Questionnaire scores, reflecting a reduction of the freezing encountered in patients’ usual environments and medication states. This study provides objective, double-blinded evidence that in a specific subgroup of Parkinsonian patients, stimulation of a caudal pedunculopontine nucleus region selectively improves gait freezing but not background deficits in step length. Bilateral stimulation was more effective than unilateral

Stepwise evolution of Paleozoic tracheophytes from South China: contrasting leaf disparity and taxic diversity

During the late Paleozoic, vascular land plants (tracheophytes) diversified into a remarkable variety of morpho- logical types, ranging from tiny, aphyllous, herbaceous forms to giant leafy trees. Leaf shape is a key determinant of both function and structural diversity of plants, but relatively little is known about the tempo and mode of leaf morphological diversification and its correlation with tracheophyte diversity and abiotic changes during this re- markable macroevolutionary event, the greening of the continents. We use the extensive record of Paleozoic tra- cheophytes from South China to explore models of morphological evolution in early land plants. Our findings suggest that tracheophyte leaf disparity and diversity were decoupled, and that they were under different selec- tive regimes. Two key phases in the evolution of South Chinese tracheophyte leaves can be recognized. In the first phase, from Devonian to Mississippian, taxic diversity increased substantially, as did leaf disparity, at the same time as they acquired novel features in their vascular systems, reproductive organs, and overall architecture. The second phase, through the Carboniferous–Permian transition, saw recovery of wetland communities in South China, associated with a further expansion of morphologies of simple leaves and an offset shift in morphospace occupation by compound leaves. Comparison with Euramerica suggests that the floras from South China were unique in several ways. The Late Devonian radiation of sphenophyllaleans contributed signif- icantly to the expansion of leaf morphospace, such that the evolution of large laminate leaves in this group oc- curred much earlier than those in Euramerica. The Pennsylvanian decrease in taxic richness had little effect on the disparity of compound leaves. Finally, the distribution in morphospace of the Permian pecopterids, gigantopterids, and equisetaleans occurred at the periphery of Carboniferous leaf morphospace

DInSAR for Road Infrastructure Monitoring: Case Study Highway Network of Rome Metropolitan (Italy)

The road network of metropolitan Rome is determined by a large number of structures located in different geological environments. To maintain security and service conditions, satellite-based monitoring can play a key role, since it can cover large areas by accurately detecting ground displacements due to anthropic activities (underground excavations, interference with other infrastructures, etc.) or natural hazards, mainly connected to the critical hydrogeological events. To investigate the area, two different Differential Interferometry Synthetic Aperture Radar (DInSAR) processing methods were used in this study: the first with open source using the Persistent Scatterers Interferometry (PSI) of SNAP-StaMPS workflow for Sentinel-1 (SNT1) and the second with the SBAS technique for Cosmo-SkyMed (CSK). The results obtained can corroborate the displacement trends due to the characteristics of the soil and the geological environments. With Sentinel-1 data, we were able to obtain the general deformation overview of the overall highways network, followed by a selection and classification of the PSI content for each section. With Cosmo-SkyMed data, we were able to increase the precision in the analysis for one sample infrastructure for which high-resolution data from CSK were available. Both datasets were demonstrated to be valuable for collecting data useful to understand the safety condition of the infrastructure and to support the maintenance actions

Novel Insect Leaf-Mining after the End-Cretaceous Extinction and the Demise of Cretaceous Leaf Miners, Great Plains, USA

<div><p>Plant and associated insect-damage diversity in the western U.S.A. decreased significantly at the Cretaceous-Paleogene (K-Pg) boundary and remained low until the late Paleocene. However, the Mexican Hat locality (ca. 65 Ma) in southeastern Montana, with a typical, low-diversity flora, uniquely exhibits high damage diversity on nearly all its host plants, when compared to all known local and regional early Paleocene sites. The same plant species show minimal damage elsewhere during the early Paleocene. We asked whether the high insect damage diversity at Mexican Hat was more likely related to the survival of Cretaceous insects from refugia or to an influx of novel Paleocene taxa. We compared damage on 1073 leaf fossils from Mexican Hat to over 9000 terminal Cretaceous leaf fossils from the Hell Creek Formation of nearby southwestern North Dakota and to over 9000 Paleocene leaf fossils from the Fort Union Formation in North Dakota, Montana, and Wyoming. We described the entire insect-feeding ichnofauna at Mexican Hat and focused our analysis on leaf mines because they are typically host-specialized and preserve a number of diagnostic morphological characters. Nine mine damage types attributable to three of the four orders of leaf-mining insects are found at Mexican Hat, six of them so far unique to the site. We found no evidence linking any of the diverse Hell Creek mines with those found at Mexican Hat, nor for the survival of any Cretaceous leaf miners over the K-Pg boundary regionally, even on well-sampled, surviving plant families. Overall, our results strongly relate the high damage diversity on the depauperate Mexican Hat flora to an influx of novel insect herbivores during the early Paleocene, possibly caused by a transient warming event and range expansion, and indicate drastic extinction rather than survivorship of Cretaceous insect taxa from refugia.</p></div

Large linear magnetoresistance in a GaAs/AlGaAs heterostructure

We report non-saturating linear Magneto Resistance (MR) in a Two-Dimensional Electron System (2DES) at a GaAs/AlGaAs heterointerface in the strongly insulating regime. We achieve this by driving the gate voltage below the pinch-off point of the device and operating it in the non-equilibrium regime with high source-drain bias. Remarkably, the magnitude of MR is as large as 500% per Tesla with respect to resistance at zero magnetic field, thus dwarfing most non-magnetic materials which exhibit this linearity. Its primary advantage over most other materials is that both linearity and the enormous magnitude are retained over a broad temperature range (0.3 K to 10 K), thus making it an attractive candidate for cryogenic sensor applications

Comparison of mine damage types on Platanaceae leaves from the Cretaceous Hell Creek Formation, Williston Basin, North Dakota; local early Paleocene localities from the Fort Union Formation, Powder River and Williston Basins, of North Dakota and Montana; and Mexican Hat, Powder River Basin, Montana.

<p>Comparison of mine damage types on Platanaceae leaves from the Cretaceous Hell Creek Formation, Williston Basin, North Dakota; local early Paleocene localities from the Fort Union Formation, Powder River and Williston Basins, of North Dakota and Montana; and Mexican Hat, Powder River Basin, Montana.</p

Insect damage on <i>Browniea serrata</i> (A–E), “<i>Ficus</i>” <i>artocarpoides</i> (F–H), and cf. <i>Ternstroemites aureavallis</i> (I).

<p>A: Circular (DT1, DT2), polylobate (DT3), and elongate slot-feeding (DT8) holes on <i>Browniea serrata</i>. Arrow indicates area expanded in the inset, showing detail of the slot-feeding hole (USNM 560169). B: Circular (DT1) and polylobate (DT3) holes on <i>Browniea serrata</i>. (USNM 560170). C: Circular galls on interveinal tissue (DT32) and secondary veins (DT34) on <i>Browniea serrata</i> (USNM 560171). D: Piercing and sucking marks with central depressions (DT46) on <i>Browniea serrata</i>. Arrow indicates area expanded in the inset, showing detail of a piercing and sucking mark (USNM 560172). E. Serpentine mine packed with spheroidal frass pellets (DT91; DMNH 35832) F: Blotch mine with internal frass trail (DT36) and polylobate holes (DT3) on “<i>Ficus</i>” <i>artocarpoides</i> (YPM 65820). G: Detail of frass trail in (F) showing spheroidal frass pellets. H: Polylobate hole (DT5) on “<i>Ficus</i>” <i>artocarpoides</i> (USNM 560173). I. cf. <i>Ternstroemites aureavallis</i> with a gall at the intersection of primary and secondary veins (DT33). Inset shows details of the gall, including a darkened outer rim and center (USNM 560174).</p

Leaf mines on <i>Cercidiphyllum genetrix</i> at Mexican Hat (A–G) and late Paleocene Wyoming localities (H–K).

<p>Mines on E–K (DT41) are interpreted as belonging to the same species of lepidopteran leaf miner, representing at least a 6 million year association between the host and miner. A: Mine characterized by overlapping trail, gradual width increase, spheroidal pellets in a frass matrix, and lack of frass in terminal portion (DT91; USNM 498161). B: Closeup of mine in (A). C: Closeup of frass trail in (A) and (B), showing spheroidal frass pellets in a darkened matrix. D: Detail of initial frass trail in (A) and (B). E: Serpentine mine characterized by initial threadlike phase arising from the base of a multi-veined leaf, widening path, smooth margins, and packed frass (DT41; arrow expanded in F; USNM 560150). F: Detail of frass trail in (E), showing tightly packed frass. G: Detail of counterpart of (E), showing packed frass in early portion of the mine. H: Threadlike mine with increasing width positioned at the base of the leaf (DT41) (Haz-Mat; USNM 560151). I: Threadlike mine with increasing width positioned at the base of the leaf between two primary veins (DT41) (Haz-Mat; USNM 560152). J: Tightly coiled mine with packed frass (DT41) (Skeleton Coast; USNM 560153). K: Poorly preserved mine positioned at the base of the leaf between two primary veins interpreted as DT41 (Skeleton Coast; USNM 560154).</p

Leaf mines assigned to DT59 (A–B), DT282 (C–D), and DT91 (E–H).

<p>A: Two linear leaf mines with widened terminal chambers along the midvein of <i>Paranymphaea crassifolia</i> (DT59; Paleocene; Paleocene Leaf –DMNH loc. 563; DMNH 20055). B: Leaf mine with widened terminal chamber along secondary vein on leaf morphotype HC265 (DT59; Cretaceous; Battleship – DMNH loc. 900; DMNH 7286). C, D: Probable mines on “<i>P.</i>” <i>nebrascensis</i> from Pyramid Butte, ND (DT282; YPM locality 86107; YPM 9796, YPM 9762). E. Initially serpentine mine with blotch-like terminal chamber on “<i>P.</i>” <i>nebrascensis</i> (DT91; YPM loc. 87150; YPM 9636) F. Serpentine mine with loosely packed frass trail on an unidentifiable leaf fragment (DT91; arrow expanded in G; Pyramid Butte - YPM loc. 86107; YPM 168194) G. Detail of frass trail in (F) showing meniscate pattern. H. Serpentine mine with medial frass trail composed of spheroidal-ellipsoidal pellets on <i>Z</i>. <i>flabella</i> (DT91). Arrow indicates area expanded in the inset, showing detail of the frass trail (YPM loc. 8403; YPM 9526).</p

Angiosperm leaf species at Mexican Hat ranked by abundance in 2004 census [19].

<p>Angiosperm leaf species at Mexican Hat ranked by abundance in 2004 census <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0103542#pone.0103542-Wilf3" target="_blank">[19]</a>.</p