The Chuacús Metamorphic Complex, central Guatemala : geochronological and geochemical constraints on its Paleozoic - Mesozoic evolution

The Chuacús Metamorphic Complex is located in Central Guatemala, between the Polochic and Motagua fault zones. It is made up of complexly intercalated, mafic and felsic high-grade gneisses, amphibolites, pelitic and quartzofeldsphatic metasediments and subordinate marbles. Mafic dikes and lenses metamorphosed to amphibolite and eclogite facies are tholeiitic and similar to mid-ocean ridge basalts. In contrast, metamorphosed intrusives (gabbro, diorite and granite) are calc-alkaline and have the geochemical signature of arc magmas. Laser Ablation Inductively Coupled Plasma Mass Spectrometry U-Pb zircon geochronology allows the recognition of three episodes of metamorphism. The first eclogite facies metamorphism (M1) is bracketed between Ordovician magmatism in the northern Chuacús Metamorphic Complex and the neighboring Rabinal granitic suite; the second corresponds to an Upper Triassic period of arc magmatism and migmatization (M2); the third high-grade metamorphic event (M3) occurred during the Late Cretaceous. The tectonic evolution of the Chuacús Metamorphic Complex began during the Early Paleozoic as a basin in the Rheic Ocean that received detrital material from the Maya Block, Acatlán and southeastern México. The Chuacús Metamorphic Complex evolved to an active margin that subducted to HP conditions during the Mid- Late Paleozoic, and then was exhumed and involved in two tectonothermal events during the Upper Triassic and Late Cretaceous. The Chuacús Metamorphic Complex was accreted to the southern Maya Block during the Late Cretaceous, as a result of the convergent tectonics between the latter and either the Greater Antillean arc or the Chortís Block

Efficacy of Multisensory Technology in Post-Stroke Cognitive Rehabilitation: A Systematic Review

Post-stroke, in addition to sensorimotor signs and symptoms, could lead to cognitive deficits. Theories of embodiment stress the role of sensorimotor system and multisensory integration in sustaining high-order cognitive domains. Despite conventional post-stroke cognitive rehabilitation being effective, innovative technologies could overcome some limitations of standard interventions and exploit bodily information during cognitive rehabilitation. This systematic review aims to investigate whether ‘multisensory technologies’ compared to usual care treatment can be a viable alternative for cognitive rehabilitation. By applying PRISMA guidelines, we extracted data and assessed the bias of 10 studies that met the required criteria. We found that multisensory technologies were at least comparable to standard treatment but particularly effective for attention, spatial cognition, global cognition, and memory. Multisensory technologies consisted principally of virtual reality alone or combined with a motion tracking system. Multisensory technologies without motion tracking were more effective than standard procedures, whereas those with motion tracking showed balanced results for the two treatments. Limitations of the included studies regarded the population (e.g., no study on acute stroke), assessment (e.g., lack of multimodal/multisensory pre-post evaluation), and methodology (e.g., sample size, blinding bias). Recent advancements in technological development and metaverse open new opportunities to design embodied rehabilitative programs

The interaction between motor simulation and spatial perspective-taking in action language: a cross-cultural study

: Growing evidence has revealed the crucial role of motor simulation and spatial perspective-taking in action language. However, there is still a lack of understanding of how motor and spatial processes interact when there are multiple actors involved, and if embodied processes are consistent across different cultures. To address this gap, we examined the interaction between motor simulation and spatial perspective-taking in action-sentences comprehension, along with the consistency of embodied processes across cultures. We collected data from Italian and US English speakers using an online sentence-picture verification task. The participants completed four conditions: two congruent (i.e., the participant is the agent in the sentence and the photo; the agent is someone else interacting with the participant in both the sentence and the picture) and two incongruent (i.e., the agents of the sentence and the picture do not match). The results show that when the perspective of the picture matched that described in the sentence-processing reaction times (RTs) were faster than in the incongruent conditions. In the congruent conditions where the agent is someone else, RTs were slower compared to the condition where the participant is the agent. This has been interpreted as claiming that motor simulation and perspective-taking are independent processes interacting during sentence comprehension (e.g., motor simulation is always run in the role of the agent, but we can adopt multiple perspectives depending on the pronouns and the contextual cues). Furthermore, Bayesian analysis provided evidence that embodied processing of action language entwines a common mechanism, suggesting cross-cultural consistency of embodied processes

ANTaging: a Research Protocol for Active Navigation Training with Virtual Reality in Mild Cognitive Impairment

Navigation is a multimodal process that requires the active computation of cognitive and bodily cues along with external environmental information. Indeed, according to the embodied cognition framework, the body and the environment build our cognitive representation of the space. This view is supported by findings in the aging population where the decline of bodily information accounts for the deficits in spatial navigation. Consequently, it is crucial to develop innovative rehabilitation solutions in aging that require the active use of bodily and cognitive processing of the space and its elements. Mild cognitive impairment is a geriatric syndrome considered to be a transitional stage between normal aging and dementia. Consequently, it is a preferred time window to administer cognitive rehabilitation programs that could slow down cognitive deterioration. In the current paper, the ANTaging protocol will be presented in its three-step studies: pilot testing, usability study, and proof-of-concept trial

A Ribosomal Misincorporation of Lys for Arg in Human Triosephosphate Isomerase Expressed in Escherichia coli Gives Rise to Two Protein Populations

We previously observed that human homodimeric triosephosphate isomerase (HsTIM) expressed in Escherichia coli and purified to apparent homogeneity exhibits two significantly different thermal transitions. A detailed exploration of the phenomenon showed that the preparations contain two proteins; one has the expected theoretical mass, while the mass of the other is 28 Da lower. The two proteins were separated by size exclusion chromatography in 3 M urea. Both proteins correspond to HsTIM as shown by Tandem Mass Spectrometry (LC/ESI-MS/MS). The two proteins were present in nearly equimolar amounts under certain growth conditions. They were catalytically active, but differed in molecular mass, thermostability, susceptibility to urea and proteinase K. An analysis of the nucleotides in the human TIM gene revealed the presence of six codons that are not commonly used in E. coli. We examined if they were related to the formation of the two proteins. We found that expression of the enzyme in a strain that contains extra copies of genes that encode for tRNAs that frequently limit translation of heterologous proteins (Arg, Ile, Leu), as well as silent mutations of two consecutive rare Arg codons (positions 98 and 99), led to the exclusive production of the more stable protein. Further analysis by LC/ESI-MS/MS showed that the 28 Da mass difference is due to the substitution of a Lys for an Arg residue at position 99. Overall, our work shows that two proteins with different biochemical and biophysical properties that coexist in the same cell environment are translated from the same nucleotide sequence frame

predictive precision medicine towards the computational challenge

The emerging fields of predictive and precision medicine are changing the traditional medical approach to disease and patient. Current discoveries in medicine enable to deepen the comprehension of diseases, whereas the adoption of high-quality methods such as novel imaging techniques (e.g. MRI, PET) and computational approaches (i.e. machine learning) to analyse data allows researchers to have meaningful clinical and statistical information. Indeed, applications of radiology techniques and machine learning algorithms rose in the last years to study neurology, cardiology and oncology conditions. In this chapter, we will provide an overview on predictive precision medicine that uses artificial intelligence to analyse medical images to enhance diagnosis, prognosis and treatment of diseases. In particular, the chapter will focus on neurodegenerative disorders that are one of the main fields of application. Despite some critical issues of this new approach, adopting a patient-centred approach could bring remarkable improvement on individual, social and business level

The role of subducted sediments in the formation of intermediate mantle-derived magmas from the Northern Colombian Andes

Unraveling the sources and processes that produce intermediate continental arc volcanoes is still a challenge for geoscientists. To address this problem, here we use comprehensive geochemical and isotopic data from Nevado del Santa Isabel and Cerro Machín volcanoes in the North Volcanic Province of Colombia, and from oceanic sediments sampled outboard the Colombian continental margin. Volcanoes along this province have been influenced by the subduction of a compositionally contrasting sedimentary column constituted by a carbonate-rich pelagic layer overlain by a clay-and-apatite-rich hemipelagic unit. The studied volcanoes exhibit the high Mg# (~60) and calc-alkaline affinities that are typical of continental arcs but display unusually high and contrasting Th(U)/La, Nb/Ta and Dy/Yb ratios and isotopic compositions. We argue that the geochemical variations within and among these volcanoes are not controlled by differentiation or crustal contamination of a parental basaltic magma but formed by melting of different kinds of subducted sedimentary materials detached from the slab as buoyantly rising diapirs at various depths. This model accounts for the reworking of refractory carbonates into arc magmatism and suggests that the geochemical diversity of the North Volcanic Province is mainly controlled by the nature of the subduction inputs and their exhumation pathways within the mantle wedge. © 201

FRAILTY VR: VR for the Rehabilitation of Frailty in the Elderly

Frailty is a preclinical condition that worsens physical health and quality of life. One of the most frequent symptoms of frailty is an increased risk of falling. It is estimated that one out of three elderly people falls at least once a year, with important consequences both for the autonomy of the individual and for the cognitive functioning and quality of life. To reduce this risk, the Italian-supported (Ministry of Health PE-2013-02355948) Frailty VR project is developing an innovative virtual reality (VR) motor rehabilitation program based on an immersive tool: a cycle-ergometer integrated in an immersive VR system (a four-screen CAVE), which allows combining motor and cognitive exercises according to a “dual-task” paradigm