8,984 research outputs found
Force and energy dissipation variations in non-contact atomic force spectroscopy on composite carbon nanotube systems
UHV dynamic force and energy dissipation spectroscopy in non-contact atomic
force microscopy were used to probe specific interactions with composite
systems formed by encapsulating inorganic compounds inside single-walled carbon
nanotubes. It is found that forces due to nano-scale van der Waals interaction
can be made to decrease by combining an Ag core and a carbon nanotube shell in
the Ag@SWNT system. This specific behaviour was attributed to a significantly
different effective dielectric function compared to the individual
constituents, evaluated using a simple core-shell optical model. Energy
dissipation measurements showed that by filling dissipation increases,
explained here by softening of C-C bonds resulting in a more deformable
nanotube cage. Thus, filled and unfilled nanotubes can be discriminated based
on force and dissipation measurements. These findings have two different
implications for potential applications: tuning the effective optical
properties and tuning the interaction force for molecular absorption by
appropriately choosing the filling with respect to the nanotube.Comment: 22 pages, 6 figure
B Physics with NRQCD: A Quenched Study
We present results on the spectrum of B mesons and heavy baryons, using a
non-relativistic formulation for the heavy and a clover action for the light
quark. We also discuss B meson decay constants and their dependency upon the
heavy meson mass.Comment: 4 pages, uuencoded compressed postscript file, contribution to
LATTICE 9
Administrative Performance of “No-Fault” Compensation for Medical Injury
No-fault is the leading alternative to traditional liability systems for resolving medically caused injuries, and policy interest in such reform reflects numerous concerns with the traditional tort system as it operates in the medical field through malpractice insurance. The administrative experience of the Florida and Virginia no-fault programs is examined
Are Alcohol Excise Taxes Good For Us? Short and Long-Term Effects on Mortality Rates
Regression results from a 30-year panel of the state-level data indicate that changes in alcohol-excise taxes cause a reduction in drinking and lower all-cause mortality in the short run. But those results do not fully capture the long-term mortality effects of a permanent change in drinking levels. In particular, since moderate drinking has a protective effect against heart disease in middle age, it is possible that a reduction in per capita drinking will result in some people drinking "too little" and dying sooner than they otherwise would. To explore that possibility, we simulate the effect of a one percent reduction in drinking on all-cause mortality for the age group 35-69, using several alternative assumptions about how the reduction is distributed across this population. We find that the long-term mortality effect of a one percent reduction in drinking is essentially nil.
Ultrasound by emergency physicians to detect abdominal aortic aneurysms: a UK case series
Early identification of abdominal aortic aneurysms in some
patients can be difficult and the diagnosis is missed in up to
30% of patients. Ultrasound cannot be used to identify a leak,
but the presence of an aneurysm in an unstable patient is
conclusive. With minimal training emergency physicians can
easily identify the aorta and thus in the early phase of
resuscitation an aneurysm can be confidently excluded. The
purpose of the examination is not to delineate the extent of
the aneurysm, but to identify those patients that will need
emergency surgery. A series of patients presented to the
department in an unstable condition with equivocal abdominal
signs. An ultrasound scan in the resuscitation room by
members of the emergency department revealed an aneurysm,
which was enough to convince the vascular surgeons to
take the patient straight to theatre with good results. In
patients who are stable, computed tomography will continue
to be used to evaluate the extent of the aneurysm and identify a leak
Heavy-light meson decay constants from NRQCD: an analysis of the 1/M corrections
We present {\it preliminary} results for the decay constants of heavy-light
mesons using NRQCD heavy and tadpole improved Clover light quarks. A comparison
is made with data obtained using Wilson light quarks. We present an analysis of
the 1/M corrections to the decay constants in the static limit and compare with
the predictions of HQET.Comment: Contribution to Lattice 95, 4 pages uuencoded compressed postscript
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New results on heavy hadron spectroscopy with NRQCD
We present results for the spectrum of b-bbar bound states in the quenched
approximation for three different values of the lattice spacing. Results for
spin-independent splittings are shown to have good scaling behaviour;
spin-dependent splittings are more sensitive to discretisation effects. We
discuss what needs to be done to match the experimental spectrum.Comment: 3 pages, contribution to Lattice'9
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