1,038 research outputs found
Fast opening diaphragm Patent
Magnetically opened diaphragm design with camera shutter and expansion tube application
Spatial and temporal variation in otolith chemistry for tautog (Tautoga onitis) in Narragansett Bay and Rhode Island coastal ponds
The elemental composition of otoliths may provide valuable
information for establishing connectivity between fish nursery grounds and adult fish populations. Concentrations
of Rb, Mg, Ca, Mn, Sr, Na, K, Sr, Pb, and Ba were determined
by using solution-based inductively coupled plasma mass spectrometry in otoliths of young-of-the year tautog
(Tautoga onitis) captured in nursery areas along the Rhode Island coast during two consecutive years. Stable oxygen (Ī“18O) and carbon (Ī“13C) isotopic ratios in young-of-the year otoliths were also analyzed with isotope ratio mass spectrometry. Chemical signatures differed significantly
among the distinct nurseries within Narragansett Bay and the coastal ponds across years. Significant differences
were also observed within nurseries from year to year. Classification accuracy to each of the five tautog nursery areas ranged from 85% to 92% across years. Because accurate
classification of juvenile tautog nursery sites was achieved, otolith chemistry can potentially be used as
a natural habitat tag
The SPICE carbon isotope excursion in Siberia: a combined study of the upper Middle Cambrian-lowermost Ordovician Kulyumbe River section, northwestern Siberian Platform
An integrated, high-resolution chemostratigraphic (C, O and Sr isotopes) and
magnetostratigraphic study through the upper Middle Cambrianālowermost Ordovician shallowmarine
carbonates of the northwestern margin of the Siberian Platform is reported. The interval was
analysed at the Kulyumbe section, which is exposed along the Kulyumbe River, an eastern tributary
of the Enisej River. It comprises the upper Ustā-Brus, Labaz, Orakta, Kulyumbe, Ujgur and lower
Iltyk formations and includes the Steptoean positive carbon isotopic excursion (SPICE) studied here
in detail from upper Cambrian carbonates of the Siberian Platform for the first time. The peak of the
excursion, showing Ī“13C positive values as high as+4.6ā°and least-altered 87Sr/86Sr ratios of 0.70909,
is reported herein from the Yurakhian Horizon of the Kulyumbe Formation. The stratigraphic position
of the SPICE excursion does not support traditional correlation of the boundary between theOrakta and
Labaz formations at the Kulyumbe River with its supposedly equivalent level in Australia, Laurentia,
South China and Kazakhstan, where the Glyptagnostus stolidotus and G. reticulatus biozones are
known to immediately precede the SPICE excursion and span the MiddleāUpper Cambrian boundary.
The CambrianāOrdovician boundary is probably situated in the middle Nyajan Horizon of the Iltyk
Formation, in which carbon isotope values show a local maximum below a decrease in the upper
part of the Nyajan Horizon, attributed herein to the Tremadocian Stage. A refined magnetic polarity
sequence confirms that the geomagnetic reversal frequency was very high during Middle Cambrian
times at 7ā10 reversals per Ma, assuming a total duration of about 10 Ma and up to 100 magnetic
intervals in the Middle Cambrian. By contrast, the sequence attributed herein to the Upper Cambrian
on chemostratigraphic grounds contains only 10ā11 magnetic intervals
Refinement Types for Secure Implementations
We present the design and implementation of a typechecker for verifying security properties of the source code of cryptographic protocols and access control mechanisms. The underlying type theory is a Ī»-calculus equipped with refinement types for expressing pre- and post-conditions within first-order logic. We derive formal cryptographic primitives and represent active adversaries within the type theory. Well-typed programs enjoy assertion-based security properties, with respect to a realistic threat model including key compromise. The implementation amounts to an enhanced typechecker for the general purpose functional language F#; typechecking generates verification conditions that are passed to an SMT solver. We describe a series of checked examples. This is the first tool to verify authentication properties of cryptographic protocols by typechecking their source code. Ā© 2008 IEEE
Spatial and temporal variation in otolith chemistry for tautog (\u3cem\u3eTautoga onitis\u3c/em\u3e) in Narragansett Bay and Rhode Island coastal ponds
The elemental composition of otoliths may provide valuable information for establishing connectivity between fish nursery grounds and adult fish populations. Concentrations of Rb, Mg, Ca, Mn, Sr, Na, K, Sr, Pb, and Ba were determined by using solution-based inductively coupled plasma mass spectrometry in otoliths of young-of-the year tautog (Tautoga onitis) captured in nursery areas along the Rhode Island coast during two consecutive years. Stable oxygen (Ī“18O) and carbon (Ī“13C) isotopic ratios in young-of-the year otoliths were also analyzed with isotope ratio mass spectrometry. Chemical signatures differed significantly among the distinct nurseries within Narragansett Bay and the coastal ponds across years. Significant differences were also observed within nurseries from year to year. Classification accuracy to each of the five tautog nursery areas ranged from 85% to 92% across years. Because accurate classification of juvenile tautog nursery sites was achieved, otolith chemistry can potentially be used as a natural habitat tag
Phenotypic and transcriptomic acclimation of the green microalga Raphidocelis subcapitata to high environmental levels of the herbicide diflufenican
Herbicide pollution poses a worldwide threat to plants and freshwater ecosystems. However, the understanding of how organisms develop tolerance to these chemicals and the associated trade-off expenses are largely unknown. This study aims to investigate the physiological and transcriptional mechanisms underlying the acclimation of the green microalgal model species Raphidocelis subcapitata (Selenastraceae) towards the herbicide diflufenican, and the fitness costs associated with tolerance development. Algae were exposed for 12 weeks (corresponding to 100 generations) to diflufenican at the two environmental concentrations 10 and 310 ng/L. The monitoring of growth, pigment composition, and photosynthetic performance throughout the experiment revealed an initial dose-dependent stress phase (week 1) with an EC50 of 397 ng/L, followed by a time-dependent recovery phase during weeks 2 to 4. After week 4, R. subcapitata was acclimated to diflufenican exposure with a similar growth rate, content of carotenoids, and photosynthetic performance as the unexposed control algae. This acclimation state of the algae was explored in terms of tolerance acquisition, changes in the fatty acids composition, diflufenican removal rate, cell size, and changes in mRNA gene expression profile, revealing potential fitness costs associated with acclimation, such as up-regulation of genes related to cell division, structure, morphology, and reduction of cell size. Overall, this study demonstrates that R. subcapitata can quickly acclimate to environmental but toxic levels of diflufenican; however, the acclimation is associated with trade-off expenses that result in smaller cell size
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Papers presented at the 22. European Physical Society conference on controlled fusion and plasma physics
This report is a compilation of the following six papers which cover research conducted at TEXT: (1) Study of plasma edge turbulence via conditional probability density functions; (2) Current density profile measurement and current diffusion experiments on TEXT-Upgrade; (3) Nonlocal transport effects in tokamak electron temperature responses; (4) BES (Beam Emission Spectroscopy) density fluctuations on TEXT-U and comparison with other diagnostics; (5) The SOL in diverted discharges in the Texas Experimental Tokamak (TEXT); and (6) Confinement and related studies in TEXT
Self-regulated charge transfer and band tilt in nm-scale polar GaN films
To date, the generic polarization of Bernardini, Fiorentini and Vanderbilt
(PBFV) has been widely used to address the issue of polarity in III-V nitride
semiconductors, but improvements in nitride materials and the performance of
optoelectronic devices have been limited. The current first-principles
calculation for the electronic structures of nm-scale [0001] GaN films show
that the internal electric fields and the band tilt of these films are in
opposite direction to those predicted by PBFV. Additionally, it is determined
that an intrinsic self-regulated charge transfer across the film limits the
electrostatic potential difference across the film, which renders the local
conduction band energy minimum (at the Ga-terminated surface) approximately
equal to the local valence band energy maximum (at the N-terminated surface).
This effect is found to occur in films thicker than ~4nm
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