10,449 research outputs found
Quantum metrology and its application in biology
Quantum metrology provides a route to overcome practical limits in sensing
devices. It holds particular relevance to biology, where sensitivity and
resolution constraints restrict applications both in fundamental biophysics and
in medicine. Here, we review quantum metrology from this biological context,
focusing on optical techniques due to their particular relevance for biological
imaging, sensing, and stimulation. Our understanding of quantum mechanics has
already enabled important applications in biology, including positron emission
tomography (PET) with entangled photons, magnetic resonance imaging (MRI) using
nuclear magnetic resonance, and bio-magnetic imaging with superconducting
quantum interference devices (SQUIDs). In quantum metrology an even greater
range of applications arise from the ability to not just understand, but to
engineer, coherence and correlations at the quantum level. In the past few
years, quite dramatic progress has been seen in applying these ideas into
biological systems. Capabilities that have been demonstrated include enhanced
sensitivity and resolution, immunity to imaging artifacts and technical noise,
and characterization of the biological response to light at the single-photon
level. New quantum measurement techniques offer even greater promise, raising
the prospect for improved multi-photon microscopy and magnetic imaging, among
many other possible applications. Realization of this potential will require
cross-disciplinary input from researchers in both biology and quantum physics.
In this review we seek to communicate the developments of quantum metrology in
a way that is accessible to biologists and biophysicists, while providing
sufficient detail to allow the interested reader to obtain a solid
understanding of the field. We further seek to introduce quantum physicists to
some of the central challenges of optical measurements in biological science.Comment: Submitted review article, comments and suggestions welcom
Caudal pneumaticity and pneumatic hiatuses in the sauropod dinosaurs Giraffatitan and Apatosaurus
Skeletal pneumaticity is found in the presacral vertebrae of most sauropod dinosaurs, but pneumaticity is much less common in the vertebrae of the tail. We describe previously unrecognized pneumatic fossae in the mid-caudal vertebrae of specimens of Giraffatitan and Apatosaurus. In both taxa, the most distal pneumatic vertebrae are separated from other pneumatic vertebrae by sequences of three to seven apneumatic vertebrae. Caudal pneumaticity is not prominent in most individuals of either of these taxa, and its unpredictable development means that it may be more widespread than previously recognised within Sauropoda and elsewhere in Saurischia. The erratic patterns of caudal pneumatization in Giraffatitan and Apatosaurus, including the pneumatic hiatuses, show that pneumatic diverticula were more broadly distributed in the bodies of the living animals than are their traces in the skeleton. Together with recently published evidence of cryptic diverticula--those that leave few or no skeletal traces--in basal sauropodomorphs and in pterosaurs, this is further evidence that pneumatic diverticula were widespread in ornithodirans, both across phylogeny and throughout anatomy
Industrial and organisational psychology
Industrial and organisational (I/0) psychology is concerned with people’s work-related values, attitudes and behaviours, and how these are influenced by the conditions in which they work. I/O psychologists contribute to both the effectiveness of organisations (e.g. improving productivity) and the health and well-being of people working within organisations. The field is related to other disciplines, such as organisational behaviour and human resource management, and also has close links with other sub-disciplines within psychology, especially social psychology and some aspects of human experimental psychology (e.g. cognition)
Why sauropods had long necks; and why giraffes have short necks
The necks of the sauropod dinosaurs reached 15 m in length: six times longer
than that of the world record giraffe and five times longer than those of all
other terrestrial animals. Several anatomical features enabled this extreme
elongation, including: absolutely large body size and quadrupedal stance
providing a stable platform for a long neck; a small, light head that did not
orally process food; cervical vertebrae that were both numerous and
individually elongate; an efficient air-sac-based respiratory system; and
distinctive cervical architecture. Relevant features of sauropod cervical
vertebrae include: pneumatic chambers that enabled the bone to be positioned in
a mechanically efficient way within the envelope; and muscular attachments of
varying importance to the neural spines, epipophyses and cervical ribs. Other
long-necked tetrapods lacked important features of sauropods, preventing the
evolution of longer necks: for example, giraffes have relatively small torsos
and large, heavy heads, share the usual mammalian constraint of only seven
cervical vertebrae, and lack an air-sac system and pneumatic bones. Among
non-sauropods, their saurischian relatives the theropod dinosaurs seem to have
been best placed to evolve long necks, and indeed they probably surpassed those
of giraffes. But 150 million years of evolution did not suffice for them to
exceed a relatively modest 2.5 m.Comment: 39 pages, 11 figures, 3 table
The Crisis in the Foreign Exchange Market
The financial crisis of 2007-2008 had major implications for the foreign exchange market. We review events and implications for exchange rates, volatility, returns to currency investing, and transaction costs. This “blow-by-blow” narrative is intended to be a resource for researchers seeking a comprehensive review of the “what, why and when” of the financial crisis in terms of foreign exchange market dynamics. An implementable financial stress index (FSI) is created and then used to illustrate the dramatic nature of the current crisis compared to earlier crises. We also examine how the global FSI might have been used to condition the exposure to the carry trade (long high interest rate currencies, short low interest rate currencies) and we show that such an index has potential value in protecting a portfolio against loss during periods of stress, although this result is subject to the important caveats of controlling for transaction costs and timely recognition of the change in regime.financial crisis, foreign exchange, exchange rates, transaction costs
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