16,360 research outputs found
The series spectra of the stripped boron atom (BIII)
In a preceding article [1], we have brought forward evidence that in "hot spark" spectra the strongest lines generally correspond to atoms from which the valence electrons have all been stripped off, so that the resulting spectrum is hydrogen-like, i.e., is due to one single electron moving between the series of levels characteristic of a simple nucleus-electron system.
For such a nucleus-electron system the Bohr theory in its elementary form [2] which dealt only with circular orbits, i.e., with variations in azimuthal quantum numbers, the radial being always zero, yielded at once the result that the energies corresponding to a given quantum state, e.g., quantum number 1, increased in the ratio 1, 4, 9, 16, etc., as the nuclear charged increased in the ratio 1, 2, 3, 4, etc. This meant physically that the frequencies corresponding to jumps from infinity to an orbit of given quantum number, technically called term-values, when divided by the square of the nuclear charge should come out a constant; otherwise stated that the constant term in the Rydberg formula should become N, 4N, 9N, 16N
Optimal fidelity of teleportation of coherent states and entanglement
We study the Braunstein-Kimble protocol for the continuous variable
teleportation of a coherent state. We determine lower and upper bounds for the
optimal fidelity of teleportation, maximized over all local Gaussian operations
for a given entanglement of the two-mode Gaussian state shared by the sender
(Alice) and the receiver (Bob). We also determine the optimal local
transformations at Alice and Bob sites and the corresponding maximum fidelity
when one restricts to local trace-preserving Gaussian completely positive maps.Comment: 10 pages, 2 figure
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Numerical modelling of microwave sintering of lunar simulants under near lunar atmospheric condition
Guidelines for the management of the foot health problems associated with rheumatoid arthritis
Background. Rheumatoid arthritis (RA) as a chronic systemic disease, commonly affects the feet, impacting
negatively on patients' quality of life. Specialist podiatrists have a prime role to play in the assessment and
management of foot and ankle problems within this patient group. However, it has been identified that in many
areas there is no specialist podiatry service, with many patients being managed by non‐specialist podiatrists.
Therefore, the North West Clinical Effectiveness Group for the Foot in Rheumatic Diseases (NWCEG) identified
the need to develop ‘practitioner facing’ guidelines for the management of specific foot health problems associated
with RA.
Methods. Members of a guideline development group from the NWCEG each reviewed the evidence for specific
aspects of the assessment and management of foot problems. Where evidence was lacking, ‘expert opinion’ was
obtained from the members of the NWCEG and added as a consensus on current and best practice. An iterative
approach was employed, with the results being reviewed and revised by all members of the group and external
reviewers before the final guideline document was produced.
Results. The management of specific foot problems (callus, nail pathology, ulceration) and the use of specific
interventions (foot orthoses, footwear, patient education, steroid injection therapy) are detailed and standards in
relation to each are provided. A diagrammatic screening pathway is presented, with the aim of guiding nonspecialist
podiatrists through the complexity of assessing and managing those patients with problems requiring
input from a specialist podiatrist and other members of the rheumatology multidisciplinary team.
Conclusion. This pragmatic approach ensured that the guidelines were relevant and applicable to current practice
as ‘best practice’, based on the available evidence from the literature and consensus expert opinion. These
guidelines provide both specialist and non‐specialist podiatrists with the essential and ‘gold standard’ aspects of
managing people with RA‐related foot problems
Non-linear optomechanical measurement of mechanical motion
Precision measurement of non-linear observables is an important goal in all
facets of quantum optics. This allows measurement-based non-classical state
preparation, which has been applied to great success in various physical
systems, and provides a route for quantum information processing with otherwise
linear interactions. In cavity optomechanics much progress has been made using
linear interactions and measurement, but observation of non-linear mechanical
degrees-of-freedom remains outstanding. Here we report the observation of
displacement-squared thermal motion of a micro-mechanical resonator by
exploiting the intrinsic non-linearity of the radiation pressure interaction.
Using this measurement we generate bimodal mechanical states of motion with
separations and feature sizes well below 100~pm. Future improvements to this
approach will allow the preparation of quantum superposition states, which can
be used to experimentally explore collapse models of the wavefunction and the
potential for mechanical-resonator-based quantum information and metrology
applications.Comment: 8 pages, 4 figures, extensive supplementary material available with
published versio
Influence of morning maternal care on the behavioural responses of 8-week-old Beagle puppies to new environmental and social stimuli
In mammals, maternal care represents a major constituent of the early-life environment and its influence on individual development has been documented in rodents, non-human primates, humans and recently in adult dogs. The quality and quantity of mother-offspring interactions exerts a multilevel regulation upon the physiological, cognitive, and behavioural development of the offspring. For example, in rats variations in maternal behaviour, such as mother-pup body contact and the amount of licking towards pups in the nest during the early days after parturition, influences the endocrine, emotional, and behavioural responses to stress in the offspring. This produces long-term consequences, which may remain into adulthood and can be transmitted to subsequent generations. Literature about maternal care in dogs and its effect on puppy behaviour is still scarce, although the topic is receiving a growing interest. The aim of the present study was to determine the effects of morning maternal care on behavioural responses of puppies to new environmental and social stimuli. In order to achieve this, maternal care (licking, ano-genital licking, nursing and mother-puppy contact) was assessed in eight litters of domestic dogs living in standard rearing conditions during the first three weeks post-partum. Puppies were subjected to two behavioural tests (arena and isolation tests) at 58-60 days of age, and their behavioural responses were video recorded and analysed. Data was analysed using multivariate analyses (PCA, PLS).During the isolation test, a higher level of maternal care was associated with more exploration and a higher latency to emit the first yelp; on the contrary, a lower level of maternal care was associated with increased locomotion, distress vocalisations and destructive behaviours directed at the enclosure.These results, comparable to those reported in laboratory rat models and to some extent to those recently reported in dog literature, highlight the importance of maternal care on the behavioural development of domestic dog puppies
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Electrospray synthesis of PLGA TIPS microspheres
We successfully demonstrate the synthesis of polymer microspheres using a single electrospray source, and show their physical characterisation. Electrospray has proven to be a versatile method to manufacture particles, giving tight control over size with quasi-monodisperse size distributions. It is a liquid atomisation technique that generates a monodisperse population of highly charged liquid droplets over a broad size range (nanometres to tens of microns). The droplets contain liquid precursors for the in-flight synthesis of particles, and control over the trajectory of these droplets can be precisely manipulated with the use of electric fields to drive them to a grounded substrate. This study reports a method to synthesize poly(lactic-co-glycolic) acid (PLGA) microspheres using the electrospray and thermally induced phase separation (TIPS) techniques, followed by subsequent freeze-drying, for particle production. These microspheres are of interest as vehicles for controlled drug release systems
Evanescent single-molecule biosensing with quantum limited precision
Sensors that are able to detect and track single unlabelled biomolecules are
an important tool both to understand biomolecular dynamics and interactions at
nanoscale, and for medical diagnostics operating at their ultimate detection
limits. Recently, exceptional sensitivity has been achieved using the strongly
enhanced evanescent fields provided by optical microcavities and nano-sized
plasmonic resonators. However, at high field intensities photodamage to the
biological specimen becomes increasingly problematic. Here, we introduce an
optical nanofibre based evanescent biosensor that operates at the fundamental
precision limit introduced by quantisation of light. This allows a four
order-of-magnitude reduction in optical intensity whilst maintaining
state-of-the-art sensitivity. It enable quantum noise limited tracking of
single biomolecules as small as 3.5 nm, and surface-molecule interactions to be
monitored over extended periods. By achieving quantum noise limited precision,
our approach provides a pathway towards quantum-enhanced single-molecule
biosensors.Comment: 17 pages, 4 figures, supplementary informatio
Series spectra of two-valence-electron atoms of boron (BII) and carbon (CIII)
Series spectra of BII and CIII.—By methods previously reported in the identification of lines in the extreme ultraviolet, 13 lines in addition to the pp′ group of BII have been identified, completing the classification of all lines known to be due to BII. Taking the 4f level as 27800 (probably correct to within 200 frequency units), the following term values were obtained for BII: 3s, 72930.8; 4s, 36655.5; 2p1, 165343.9; 2p2,3, 165362.7; 3p1, 59006.5; 3p2,3, 59010.0; 3d, 52054.2; 4d, 28640.4; 5f, 17795.7; 2S, 194325.9; 3S, 66665.1; 2P, 120929.4; 3D, 48410.3. In the case of CIII, 8 lines in addition to the pp′ group were identified, and taking the 4f level as 62600, the following term values were obtained for CIII: 3s, 146197.2; 2p, 331939.2; 3p1, 124685.8; 3p2, 124698.6; 3p3, 124704.1; 3d, 114387.2; 2S, 375463.1; 2P, 273111.0.
Progression of frequency separations and of screening constants for regular doublets for Li to O is shown in Table VI, for one to six valence electrons. The separation (2p2-2p1) or (2p3-2p1) regularly decreases and the constant s regularly increases, for a given element, with the number of valence electrons, irrespective of the fact that both doublets and triplets are involved
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