1,741 research outputs found
Preparation of an ultra-cold sample of ammonia molecules for precision measurements
We present experiments in which an ultra-cold sample of ammonia molecules is
released from an electrostatic trap and recaptured after a variable time. It is
shown that, by performing adiabatic cooling before releasing the molecules and
adiabatic re-compression after they are recaptured, we are able to observe
molecules even after more than 10 ms of free expansion. A coherent measurement
performed during this time will have a statistical uncertainty that decreases
approximately as the inverse of the square root of the expansion time. This
offers interesting prospects for high-resolution spectroscopy and precision
tests of fundamental physics theories
Patellofemoral pain: challenging current practice – a case report
Patellofemoral pain (PFP) is a common problem in young people, with 1 in 6 suffering at any one time. It is unclear which management approach is the optimal method for treating PFP in the long term, with traditional physiotherapy examination focusing on assessing for specific structural dysfunction. A rationale for a different assessment and treatment approach, one that moves the focus away from a biomedical/tissue pathology model towards one directed at the neurophysiology of pain, has been suggested.
The patient was a 21 year old male with a 6 year history of PFP with previous failed physiotherapeutic treatment. He reported previous multiple healthcare practitioners' advice to avoid activities that were painful as reasons for being unable to participate in sporting activities. No specific structural testing was performed, such as specific muscle strength, length, foot position, patella movement and position, or movement patterns.
Descriptions of tissue based pathology models of pain, e.g. patella mal-tracking, were actively discouraged and challenged. The patient was taught to perform one uncomfortable/painful exercise as part of his rehabilitation programme twice a day.
The patient achieved 80% improvement in his symptoms over 7 appointments and a return to physical activity following a 5 month rehabilitation programme purposively designed to elicit pain by means of gradually exercising and loading the tissues. This case report highlights the need for further research into exercise protocols for patients suffering with PFP based upon neurophysiology models of pain
UV frequency metrology on CO (a3Pi); isotope effects and sensitivity to a variation of the proton-to-electron mass ratio
UV frequency metrology has been performed on the a3Pi - X1Sigma+ (0,0) band
of various isotopologues of CO using a frequency-quadrupled injection-seeded
narrow-band pulsed Titanium:Sapphire laser referenced to a frequency comb
laser. The band origin is determined with an accuracy of 5 MHz (delta \nu / \nu
= 3 * 10^-9), while the energy differences between rotational levels in the
a3Pi state are determined with an accuracy of 500 kHz. From these measurements,
in combination with previously published radiofrequency and microwave data, a
new set of molecular constants is obtained that describes the level structure
of the a3Pi state of 12C16O and 13C16O with improved accuracy. Transitions in
the different isotopologues are well reproduced by scaling the molecular
constants of 12C16O via the common mass-scaling rules. Only the value of the
band origin could not be scaled, indicative of a breakdown of the
Born-Oppenheimer approximation. Our analysis confirms the extreme sensitivity
of two-photon microwave transitions between nearly-degenerate rotational levels
of different Omega-manifolds for probing a possible variation of the
proton-to-electron mass ratio, \mu=m_p/m_e, on a laboratory time scale
UC-296 Cybersecurity Park
Cybersecurity Park is an educational VR game intended for middle-school-age children that aims to demonstrate a wide range of cybersecurity concepts to the players. Such concepts include hacking ethics and types of hackers, cryptography, Trojan Horse / ransomware viruses, and authentication and authorization. These concepts are split into various mini-games that the player can freely navigate to from the hub they spawn in. For example, in the mini-game showcasing the Trojan Horse concept, players play as a knight defending a castle from evildoers. Visitors will approach the castle and ask access into the castle, and, based on the actions by the visitors, the player will choose whether or not to allow access into the castle. The player acts as a firewall, and the visitors act like applications requesting access into a computer. If a bad visitor/application is let into the castle (representing a computer), then the castle will begin to catch fire. This one of six mini-games present within this game, and video demonstrations of some of these mini-games are provided
The Politics of the 1965 Gold Reserve Law
The major focus of this study is the 1965 gold reserve law. Thislaw was both an economic and political solution to a number of problemswhich are discussed under the general subject of the United States balanceof payments. I have used the 1965 law to illustrate many processes withinthe American political system
Multiple packets of neutral molecules revolving for over a mile
The level of control that one has over neutral molecules in beams dictates
their possible applications. Here we experimentally demonstrate that
state-selected, neutral molecules can be kept together in a few mm long packet
for a distance of over one mile. This is accomplished in a circular arrangement
of 40 straight electrostatic hexapoles through which the molecules propagate
over 1000 times. Up to 19 packets of molecules have simultaneously been stored
in this ring structure. This brings the realization of a molecular low-energy
collider within reach
(1R,3S)-N-Benzhydryl-2-benzyl-6,7-dimethÂoxy-1-phenyl-1,2,3,4-tetraÂhydroÂisoquinoline-3-carbothioÂamide
The title compound, C38H36N2O2S, has a heterocyclic ring that assumes a half-chair conformation. The phenyl rings of neighbouring molÂecules align forming alternating chains parallel to [100] within the crystal packing. The absolute stereochemistry of the crystal was confirmed to be R,S at the 1- and 3-positions, respectively, by proton NMR spectroscopy. A single intraÂmolecular N—H⋯N hydrogen bond is observed
(S)-Benzyl 3-phenylÂcarbamoyl-1,2,3,4-tetraÂhydroÂisoquinoline-2-carboxylÂate
There are two independent molÂecules in the asymmetric unit of the title compound, C24H22N2O3. The heterocyclic ring assumes a twisted boat conformation and N—H⋯O interÂactions help to construct the three-dimensional network within the crystal packing
Social Network and Content Analysis of the North American Carbon Program as a Scientific Community of Practice
The North American Carbon Program (NACP) was formed to further the scientific understanding of sources, sinks, and stocks of carbon in Earth's environment. Carbon cycle science integrates multidisciplinary research, providing decision-support information for managing climate and carbon-related change across multiple sectors of society. This investigation uses the conceptual framework of com-munities of practice (CoP) to explore the role that the NACP has played in connecting researchers into a carbon cycle knowledge network, and in enabling them to conduct physical science that includes ideas from social science. A CoP describes the communities formed when people consistently engage in shared communication and activities toward a common passion or learning goal. We apply the CoP model by using keyword analysis of abstracts from scientific publications to analyze the research outputs of the NACP in terms of its knowledge domain. We also construct a co-authorship network from the publications of core NACP members, describe the structure and social pathways within the community. Results of the content analysis indicate that the NACP community of practice has substantially expanded its research on human and social impacts on the carbon cycle, contributing to a better understanding of how human and physical processes interact with one another. Results of the co-authorship social network analysis demonstrate that the NACP has formed a tightly connected community with many social pathways through which knowledge may flow, and that it has also expanded its network of institutions involved in carbon cycle research over the past seven years
Typing Supernova Remnants Using X-ray Line Emission Morphologies
We present a new observational method to type the explosions of young
supernova remnants (SNRs). By measuring the morphology of the Chandra X-ray
line emission in seventeen Galactic and Large Magellanic Cloud SNRs with a
multipole expansion analysis (using power ratios), we find that the
core-collapse SNRs are statistically more asymmetric than the Type Ia SNRs. We
show that the two classes of supernovae can be separated naturally using this
technique because X-ray line morphologies reflect the distinct explosion
mechanisms and structure of the circumstellar material. These findings are
consistent with recent spectropolarimetry results showing that core-collapse
SNe are intrinsically more asymmetric.Comment: 4 pages, 1 figure, accepted for publication in ApJ
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