The effects of ageing and exercise on skeletal muscle structure and function

Musculoskeletal ageing is associated with profound morphological and functional changes that increase fall risk and disease incidence and is characterised by age-related reductions in motor unit number and atrophy of muscle fibres, particularly type II fibres. Decrements in functional strength and power are relatively modest until the 6th decade, after which the rate of loss exponentially accelerates, particularly beyond the 8th decade of life. Physical activity is a therapeutic modality that can significantly attenuate age-related decline. The underlying signature of ageing, as manifested by perturbed redox homeostasis, leads to a blunting of acute and chronic redox regulated exercise adaptations. Impaired redox regulated exercise adaptations are mechanistically related to altered exercise-induced reactive oxygen and nitrogen species generation and a resultant failure to properly activate redox regulated signaling cascades. Despite the aforementioned specific impairment in redox signaling, exercise induces a plethora of beneficial effects, irrespective of age. There is, therefore, strong evidence for promoting regular physical exercise, especially progressive resistance training as a lifelong habitual practice

The dose response for sprint interval training interventions may affect the time course of aerobic training adaptations

Low vs. high volume sprint-interval training (SIT) sessions have shown similar physiological benefits after 8 weeks. However, the dose response and residual effects of shorter SIT bouts (<10 s) are unknown. Following a 6-wk control period, 13 healthy inactive males were assigned to a low dose (LDG: n = 7) or high dose (HDG: n = 6) supervised 6-wk intervention: ×2/wk of SIT (LDG = 2 sets of 5 × 6 s ON: 18 s OFF bouts; HDG = 4–6 sets); ×1/wk resistance training (3 exercises at 3 × 10 reps). Outcome measures were tested pre and post control (baseline (BL) 1 and 2), 72 h post (0POST), and 3-wk post (3POST) intervention. At 0POST, peak oxygen uptake (VO2peak) increased in the LDG (+16%) and HDG (+11%) vs. BL 2, with no differences between groups (p = 0.381). At 3POST, VO2peak was different between LDG (−11%) and HDG (+3%) vs. 0POST. Positive responses for the intervention’s perceived enjoyment (PE) and rate of perceived exertion (RPE) were found for both groups. Blood pressure, blood lipids, or body composition were not different between groups at any time point. Conclusion: LDG and HDG significantly improved VO2peak at 0POST. However, findings at 3POST suggest compromised VO2peak at 0POST in the HDG due to the delayed time course of adaptations. These findings should be considered when implementing high-dose SIT protocols for non-athletic population

Current status of computational methods for transonic unsteady aerodynamics and aeroelastic applications

The current status of computational methods for unsteady aerodynamics and aeroelasticity is reviewed. The key features of challenging aeroelastic applications are discussed in terms of the flowfield state: low-angle high speed flows and high-angle vortex-dominated flows. The critical role played by viscous effects in determining aeroelastic stability for conditions of incipient flow separation is stressed. The need for a variety of flow modeling tools, from linear formulations to implementations of the Navier-Stokes equations, is emphasized. Estimates of computer run times for flutter calculations using several computational methods are given. Applications of these methods for unsteady aerodynamic and transonic flutter calculations for airfoils, wings, and configurations are summarized. Finally, recommendations are made concerning future research directions

Academic literacies twenty years on: a community-sourced literature review

In 1998, the paper ‘Student writing in higher education: an academic literacies approach’ by Mary Lea and Brian Street reinvigorated debate concerning ‘what it means to be academically literate’ (1998, p.158). It proposed a new way of examining how students learn at university and introduced the term ‘academic literacies’. Subsequently, a body of literature has emerged reflecting the significant theoretical and practical impact Lea and Street’s paper has had on a range of academic and professional fields. This literature review covers articles selected by colleagues in our professional communities of the Association for Learning Development in Higher Education (ALDinHE), BALEAP the global forum for English for Academic Purposes (EAP) professionals, and the European Association of Teachers of Academic Writing (EATAW). As a community-sourced literature review, this text brings together reviews of wide range of texts and a diverse range of voices reflecting a multiplicity of perspectives and understandings of academic literacies. We have organised the material according to the themes: Modality, Identity, Focus on text, Implications for research, and Implications for practice. We conclude with observations relevant to these themes, which we hope will stimulate further debate, research and professional collaborations between our members and subscribers

Unmixing Detrital Zircon U-Pb Ages Reveals Tectonic and Climatic Depositional Influences on the Carboniferous Ansilta Formation, Calingasta-Uspallata Basin, Western Argentina

The Late Paleozoic Ice Age (LPIA) was a principal control of sedimentation across Gondwana from the late Devonian through early Permian. We assess the hypothesis that glacial to interglacial transitions in western Argentina were the primary control influencing sediment routing patterns among the various Carboniferous-Permian basins in western Argentina. The Carboniferous Ansilta Formation consists of glaciomarine, nearshore, and fluvial systems deposited during the LPIA along the eastern margin of the Calingasta-Uspallata Basin in Argentina. The lower, glacially influenced succession of the Ansilta Formation records at least five glacial advances; the upper succession of consists of progradational shallow marine, deltaic, and fluvial strata. We combine 1225 new U–Pb zircon ages from six samples of the Carboniferous Ansilta Formation in the Calingasta-Uspallata Basin with 5864 U–Pb ages from 147 published samples in the detritalPy-mix forward mixture model to characterize provenance shifts. For the glacially influenced lower Ansilta Formation, sediment was derived locally from the Protoprecordillera, which was a prominent highland with alpine glaciers flowing west and east into the CalingastaUspallata and Paganzo basins, respectively. Thus, there was little or no connection between these two basins during Serpukhovian-Bashkirian glaciation. The fluvial/deltaic upper Ansilta had distal sediment sources in the Sierras Pampeanas. Furthermore, our results support the collapse of the Protoprecordillera topographic barrier, enabling drainage patterns connecting the Paganzo and Calingasta-Uspallata basins by late Pennsylvanian-early Permian time

Quantitative Effects of Electrodialysis Membrane Fouling

To meet the ever-increasing global demand for fresh water, research is constantly being conducted on separation and purification methods. Electrodialysis (ED) is one of the major technologies that seems able to make significant headway in combatting water shortages. As with all technologies, it is limited by certain aspects, one of those being membrane fouling. This research takes a look at the surprisingly unexamined phenomenon of membrane fouling in ED systems. The ED system studied was tested using conductivity probing, limiting current density analysis, and quartz crystal microbalance with dissipation analysis. Investigation of fouling effects commonly seen in ubiquitous ED systems produced data indicating that fouling increased rather than decreased permeant flux and separation rate, and increased the limiting current density of the system from 23.98 (A/m2) to 31.43 (A/m2). A brief explanation is offered for this phenomenon, and future research directions are recommended

Sedimentology, Sequence Stratigraphy, and High-Precision U-Pb Age Constraints on the Late Paleozoic Ansilta Formation, Calingasta-Uspallata Basin, NW Argentina

The Ansilta Formation, located several kilometers east of the Astronomical Observatory El Leoncito near Barreal, San Juan Province, Argentina was deposited during the late Mississippian to early Pennsylvanian. This succession includes glacimarine, nearshore, and fluvial systems deposited at the mid-Carboniferous portion of the late Paleozoic ice age within the Calingasta—Uspallata Basin on the western margin of the Protoprecordillera. The lower member of the Ansilta Formation is equivalent to the nearby Leoncito, Majaditas, and Hoyada Verde formations, and is composed of diamictite, conglomerates, sandstones, pebbly mudstones, and laminated mudstone. Glacial environments are unique in that facies changes occur as a result of glacial fluctuations that may be independent from changes of relative sea-level. For this reason, an alternative conceptual framework outside of the traditional sequence stratigraphic approach is necessary to understand these strata. The lower glacial member (0-540 m) records at least five glacial advances, where glacial dynamic signatures are interpreted using glacial sequence stratigraphy and glacial systems tracts (GST). The upper member of the Ansilta Formation (540-700 m) consists of progradational shallow marine and fluvial strata with conglomerates, sandstones, and mudstones. This assemblage shows no direct evidence of continued glaciation in the basin due to the absence of glacially faceted clasts and diamictites, representing a major deglaciation phase in western Argentina and is part of the stepped deglaciation across Gondwana that ended elsewhere in the late Permian. Additionally, samples were collected from various sandstones throughout the formation for detrital zircon U-Pb geochronology to determine sediment provenance as a way of isolating different glacial sources and to assist in bracketing sequences. Results indicate multiple glacial advances, with at least three distinct source areas. The lowermost stage includes locally sourced and recycled underlying Ordovician and Silurian basement, represented by similar Famatinian (460-500 Ma) and Mesoproterozoic peaks (1050-1400 Ma) peaks, with the Mesoproterozoic source likely reworked locally from the underlying basement or derived from the Sierra de Pie de Palo range in the western Sierra Pampeanas. The middle stages of the upper glacial member show a population distinct unto itself, with a peak during the Mississippian (330-360 Ma). Pebble counts recorded along the section showed increasing quantities of plutonic and metasedimentary rock clasts and decreasing amounts of sedimentary clasts from the bottom to the top of the glacial interval. This is attributed to the un-roofing of sedimentary strata and subsequent erosion of the crystalline core of the Protoprecordillera, resulting in the influx of Carboniferous first-cycle sediments. The uppermost stage shows relations based on K-S statistical results to formations within the Paganzo basin to the northeast, which could represent a temporal link between the Calingasta-Uspallata and Paganzo basins during the late Carboniferous, manifested as distal outwash from braided fluvial systems