14 research outputs found
Evidence formulti-cycle sedimentation and provenance constraints from
Laser ablation ICP-MS UâPb analyses were conducted on detrital zircons of Triassic sandstone and conglomerate
from the Lusitanian basin in order to: i) document the age spectra of detrital zircon; ii) compare UâPb detrital
zircon ages with previous published data obtained from Upper Carboniferous, Ordovician, Cambrian and Ediacaran
sedimentary rocks of the pre-Mesozoic basement of western Iberia; iii) discuss potential sources; and iv) test the
hypothesis of sedimentary recycling. UâPb dating of zircons established a maximum depositional age for this
deposit as Permian (ca. 296Ma),which is about sixty million years older compared to the fossil content recognized
in previous studies (Upper Triassic). The distribution of detrital zircon ages obtained points to common source
areas: the OssaâMorena and Central Iberian zones that outcrop in and close to the PortoâTomar fault zone. The
high degree of immaturity and evidence of little transport of the Triassic sediment suggests that granite may
constitute primary crystalline sources. The Carboniferous age of ca. 330 Ma for the best estimate of crystallization
for a granite pebble in a Triassic conglomerate and the PermianâCarboniferous ages (ca. 315Ma) found in detrital
zircons provide evidence of the denudation of Variscan and Cimmerian granites during the infilling of continental
rift basins in western Iberia. The zircon age spectra found in Triassic strata are also the result of recycling from the
Upper Carboniferous Buçaco basin,which probably acted as an intermediate sediment repository.UâPb data in this
study suggest that the detritus from the Triassic sandstone and conglomerate of the Lusitanian basin is derived
fromlocal source areas with features typical of Gondwana,with no sediment from external sources from Laurussia
or southwestern Iberia
The development of a 100 KHZ switched-mode power supply
Thesis (Masters Diploma (Electricity Engineering) -- Cape Technikon, Cape Town,1991At the time of the design the maximum allowable operating
frequency for an output power of between 200 and 250 watts
was 100 kHz. Although a 600 kHz operating frequency could
have been achieved, it would only be at a very low output
power level.
To maximise the current components available, a 210 watt
100 kHz direct-off-line switched-mode power supply was
developed. The design presented can be used to power any
compatible IBM XT/AT personal computer.
The prototype was tested. An overall efficiency of 61% was
achieved. The final prototype required 1 521 cm3 and weighed
approximately 980 g, representing a power to volume ratio of
0.14 W/cm3 (2.26 W/inch3).
Detailed procedures are also presented to help with the
design and selection of the reactive components.
Special design features include the half-bridge push-pull
topology, MOSFETS as power switches, digital current
limiting, primary power limiting, multiple outputs and fault
counting to name but a few
Characterizing cellular mechanical phenotypes with mechano-node-pore sensing.
The mechanical properties of cells change with their differentiation, chronological age, and malignant progression. Consequently, these properties may be useful label-free biomarkers of various functional or clinically relevant cell states. Here, we demonstrate mechano-node-pore sensing (mechano-NPS), a multi-parametric single-cell-analysis method that utilizes a four-terminal measurement of the current across a microfluidic channel to quantify simultaneously cell diameter, resistance to compressive deformation, transverse deformation under constant strain, and recovery time after deformation. We define a new parameter, the whole-cell deformability index (wCDI), which provides a quantitative mechanical metric of the resistance to compressive deformation that can be used to discriminate among different cell types. The wCDI and the transverse deformation under constant strain show malignant MCF-7 and A549 cell lines are mechanically distinct from non-malignant, MCF-10A and BEAS-2B cell lines, and distinguishes between cells treated or untreated with cytoskeleton-perturbing small molecules. We categorize cell recovery time, ÎTr, as instantaneous (ÎTr ~ 0 ms), transient (ÎTr †40ms), or prolonged (ÎTr > 40ms), and show that the composition of recovery types, which is a consequence of changes in cytoskeletal organization, correlates with cellular transformation. Through the wCDI and cell-recovery time, mechano-NPS discriminates between sub-lineages of normal primary human mammary epithelial cells with accuracy comparable to flow cytometry, but without antibody labeling. Mechano-NPS identifies mechanical phenotypes that distinguishes lineage, chronological age, and stage of malignant progression in human epithelial cells
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Characterizing cellular mechanical phenotypes with mechano-node-pore sensing.
The mechanical properties of cells change with their differentiation, chronological age, and malignant progression. Consequently, these properties may be useful label-free biomarkers of various functional or clinically relevant cell states. Here, we demonstrate mechano-node-pore sensing (mechano-NPS), a multi-parametric single-cell-analysis method that utilizes a four-terminal measurement of the current across a microfluidic channel to quantify simultaneously cell diameter, resistance to compressive deformation, transverse deformation under constant strain, and recovery time after deformation. We define a new parameter, the whole-cell deformability index (wCDI), which provides a quantitative mechanical metric of the resistance to compressive deformation that can be used to discriminate among different cell types. The wCDI and the transverse deformation under constant strain show malignant MCF-7 and A549 cell lines are mechanically distinct from non-malignant, MCF-10A and BEAS-2B cell lines, and distinguishes between cells treated or untreated with cytoskeleton-perturbing small molecules. We categorize cell recovery time, ÎTr, as instantaneous (ÎTr ~ 0 ms), transient (ÎTr †40ms), or prolonged (ÎTr > 40ms), and show that the composition of recovery types, which is a consequence of changes in cytoskeletal organization, correlates with cellular transformation. Through the wCDI and cell-recovery time, mechano-NPS discriminates between sub-lineages of normal primary human mammary epithelial cells with accuracy comparable to flow cytometry, but without antibody labeling. Mechano-NPS identifies mechanical phenotypes that distinguishes lineage, chronological age, and stage of malignant progression in human epithelial cells
Toward an atlas of Salish Sea biodiversity: the flora and fauna of Galiano Island, British Columbia, Canada. Part I. Marine zoology
Based on records dating from 1859 to 2021, we provide an overview of the marine animal diversity reported for Galiano Island, British Columbia, Canada. More than 650 taxa are represented by 20,000 species occurrence records in this curated dataset, which includes dive records documented through the Pacific Marine Life Surveys, museum voucher specimens, ecological data and crowd-sourced observations from the BC Cetacean Sightings Network and iNaturalist.We describe Galiano Island's marine animal diversity in relation to the Salish Sea's overall biodiversity and quantify the proportional contributions of different types of sampling effort to our current local knowledge. Overviews are provided for each taxonomic group in a format intended to be accessible to amateur naturalists interested in furthering research into the region's marine biodiversity. In summary, we find that the Pacific Marine Life Surveys, a regional community science diving initiative, account for 60% of novel records reported for Galiano Island. Voucher specimens account for 19% and crowd-sourced biodiversity data 18% of novel records, respectively, with the remaining 3% of reports coming from other sources. These findings shed light on the complementarity of different types of sampling effort and demonstrate the potential for community science to contribute to the global biodiversity research community. We present a biodiversity informatics framework that is designed to enable these practices by supporting collaboration among researchers and communities in the collection, curation and dissemination of biodiversity data
Toward an atlas of Salish Sea biodiversity: the flora and fauna of Galiano Island, British Columbia, Canada. Part I. Marine zoology
Based on records dating from 1859 to 2021, we provide an overview of the marine animal diversity reported for Galiano Island, British Columbia, Canada. More than 650 taxa are represented by 20,000 species occurrence records in this curated dataset, which includes dive records documented through the Pacific Marine Life Surveys, museum voucher specimens, ecological data and crowd-sourced observations from the BC Cetacean Sightings Network and iNaturalist.We describe Galiano Island's marine animal diversity in relation to the Salish Sea's overall biodiversity and quantify the proportional contributions of different types of sampling effort to our current local knowledge. Overviews are provided for each taxonomic group in a format intended to be accessible to amateur naturalists interested in furthering research into the region's marine biodiversity. In summary, we find that the Pacific Marine Life Surveys, a regional community science diving initiative, account for 60% of novel records reported for Galiano Island. Voucher specimens account for 19% and crowd-sourced biodiversity data 18% of novel records, respectively, with the remaining 3% of reports coming from other sources. These findings shed light on the complementarity of different types of sampling effort and demonstrate the potential for community science to contribute to the global biodiversity research community. We present a biodiversity informatics framework that is designed to enable these practices by supporting collaboration among researchers and communities in the collection, curation and dissemination of biodiversity data