590 research outputs found
Boundedness properties of fermionic operators
The fermionic second quantization operator is shown to be
bounded by a power of the number operator given that the operator
belongs to the -th von Neumann-Schatten class, . Conversely,
number operator estimates for imply von Neumann-Schatten
conditions on . Quadratic creation and annihilation operators are treated as
well.Comment: 15 page
3D sedimentary architecture showing the inception of an Ice Age
Abstract: Northeast Atlantic climate shifted into the Quaternary Ice Age around 2.6 M yr ago. Until now, however, the detailed changes associated with this inception of an Ice Age have remained obscure. New high-quality three-dimensional seismic data reveal a detailed geological record of buried surfaces, landforms and sedimentary architecture over vast parts of the Norwegian North Sea. Here, we show the sequence of near-coast geological events spanning the Northeast Atlantic inception of an Ice Age. We identify the location of immediate pre-glacial fluvially derived sandy systems where rivers from the Norwegian mainland built marine deltas. The stratigraphic position of a large submarine channel, formed by enhanced meltwater from initial build-up of local glaciers, is also shown. Finally, we document the transition to full ice-sheet growth over Scandinavia from the ice sheetâs earliest position to the later pattern of debris-flow lobes reaching the present-day shelf edge
Applications of Canonical Transformations
Canonical transformations are defined and discussed along with the
exponential, the coherent and the ultracoherent vectors. It is shown that the
single-mode and the -mode squeezing operators are elements of the group of
canonical transformations. An application of canonical transformations is made,
in the context of open quantum systems, by studying the effect of squeezing of
the bath on the decoherence properties of the system. Two cases are analyzed.
In the first case the bath consists of a massless bosonic field with the bath
reference states being the squeezed vacuum states and squeezed thermal states
while in the second case a system consisting of a harmonic oscillator
interacting with a bath of harmonic oscillators is analyzed with the bath being
initially in a squeezed thermal state.Comment: 14 page
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3D sedimentary architecture showing the inception of an Ice Age
Abstract: Northeast Atlantic climate shifted into the Quaternary Ice Age around 2.6 M yr ago. Until now, however, the detailed changes associated with this inception of an Ice Age have remained obscure. New high-quality three-dimensional seismic data reveal a detailed geological record of buried surfaces, landforms and sedimentary architecture over vast parts of the Norwegian North Sea. Here, we show the sequence of near-coast geological events spanning the Northeast Atlantic inception of an Ice Age. We identify the location of immediate pre-glacial fluvially derived sandy systems where rivers from the Norwegian mainland built marine deltas. The stratigraphic position of a large submarine channel, formed by enhanced meltwater from initial build-up of local glaciers, is also shown. Finally, we document the transition to full ice-sheet growth over Scandinavia from the ice sheetâs earliest position to the later pattern of debris-flow lobes reaching the present-day shelf edge
A persistent Norwegian Atlantic Current through the Pleistocene glacials
Changes in oceanâcirculation regimes in the northern North Atlantic and the Nordic Seas may affect not only the Arctic but potentially hemispheric or even global climate. Therefore, unraveling the longâterm evolution of the North Atlantic CurrentâNorwegian Atlantic Current system through the Pleistocene glaciations could yield useful information and climatological context for understanding contemporary changes. In this work, ~50,000 km2 of 3âD seismic reflection data are used to investigate the Pleistocene stratigraphy for evidence of paleoâoceanographic regimes on the midâNorwegian margin since 2.58 Ma. Across 33 semicontinuous regional paleoâseafloor surfaces ~17,500 iceberg scours have been mapped. This mapping greatly expands our spatiotemporal understanding of currents and iceberg presence in the eastern Nordic Seas. The scours display a dominant southwestânortheast trend that complements previous sedimentological and numerical modeling studies that suggest northwardâflowing currents in the Norwegian Sea during the Pleistocene. This paleoâoceanographic study suggests that through many of the Pleistocene glaciations, the location of surface ocean currents in the Norwegian Sea and, by extension, the eastern North Atlantic, were broadly similar to the present
Site-specific incorporation of phosphotyrosine using an expanded genetic code.
Access to phosphoproteins with stoichiometric and site-specific phosphorylation status is key to understanding the role of protein phosphorylation. Here we report an efficient method to generate pure, active phosphotyrosine-containing proteins by genetically encoding a stable phosphotyrosine analog that is convertible to native phosphotyrosine. We demonstrate its general compatibility with proteins of various sizes, phosphotyrosine sites and functions, and reveal a possible role of tyrosine phosphorylation in negative regulation of ubiquitination
Experimental ovarian transplantation on stomach for bone repair in ovariohysterectomized rabbits
Seabed geomorphology: a two-part classification system
The BGS has developed a two-
part classification system
(âMorphologyâ and âGeomorphologyâ)
to facilitate work on a new âS
eabed Geomorphologyâ mapping initia
tive, and this classification
system is the focus of this report. As stated in
the Foreword, the rationale
and the basic framework
of the classification system were conceived and es
tablished within BGS, but
recent collaboration
within the
MAREANO
-Norway,
INFOMAR
-Ireland, and
MAREMAP
-UK (MIM) partnership
has led to significant improvement of the classifi
cation system, and this report. To further support
this effort, existing BGS GIS tools (SIGMA) ha
ve been adapted to apply this two-part
classification system for more efficient geom
orphological mapping in the marine environment.
This report:
provides a brief background on seabed mapping
and characterisation, as well as how this
science has been addressed
historically within BGS;
describes the current motiva
tion to conduct seabed geom
orphological mapping, and the
requirement for a new set of t
ools to facilitate this work;
describes the logical framework that
underpins the classification system;
outlines the attributes of the classification
system, how it can be applied, and discusses
the advantages and limitations of the approach.
It is anticipated that through testing and usage,
the classification syst
em will be revised and
improved over time, with updated versions released
through MIM partnershi
p. It is also planned
that a further âuser guideâ report
will be produced for the classifi
cation system and the GIS tools,
including thematic details (e.g.
background information on âcoastalâ
or âglacialâ features) and a
feature glossary
Population Pharmacokinetic Modelling of FE 999049, a Recombinant Human Follicle-Stimulating Hormone, in Healthy Women After Single Ascending Doses
OBJECTIVE: The purpose of this analysis was to develop a population pharmacokinetic model for a novel recombinant human follicle-stimulating hormone (FSH) (FE 999049) expressed from a human cell line of foetal retinal origin (PER.C6(ÂŽ)) developed for controlled ovarian stimulation prior to assisted reproductive technologies.METHODS: Serum FSH levels were measured following a single subcutaneous FE 999049 injection of 37.5, 75, 150, 225 or 450 IU in 27 pituitary-suppressed healthy female subjects participating in this first-in-human single ascending dose trial. Data was analysed by nonlinear mixed effects population pharmacokinetic modelling in NONMEM 7.2.0.RESULTS: A one-compartment model with first-order absorption and elimination rates was found to best describe the data. A transit model was introduced to describe a delay in the absorption process. The apparent clearance (CL/F) and apparent volume of distribution (V/F) estimates were found to increase with body weight. Body weight was included as an allometrically scaled covariate with a power exponent of 0.75 for CL/F and 1 for V/F.CONCLUSIONS: The single-dose pharmacokinetics of FE 999049 were adequately described by a population pharmacokinetic model. The average drug concentration at steady state is expected to be reduced with increasing body weight
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