1,330 research outputs found
Evidence for from photoproduction and consequence for chiral-symmetry restoration at high mass
We report a partial-wave analysis of new data on the double-polarization
variable for the reactions and
and of further data published earlier. The analysis within the Bonn-Gatchina
(BnGa) formalism reveals evidence for a poorly known baryon resonance, the
one-star . This is the lowest-mass resonance with
spin-parity . Its mass is significantly higher than the mass of its
parity partner which is the lowest-mass
resonance with spin-parity . It has been suggested that chiral
symmetry might be restored in the high-mass region of hadron excitations, and
that these two resonances should be degenerate in mass. Our findings are in
conflict with this prediction.Comment: 5 pages, 3 figures; Physics Letters B in pres
Minimal Position-Velocity Uncertainty Wave Packets in Relativistic and Non-relativistic Quantum Mechanics
We consider wave packets of free particles with a general energy-momentum
dispersion relation . The spreading of the wave packet is determined by
the velocity v = \p_p E. The position-velocity uncertainty relation is saturated by minimal uncertainty wave
packets . In addition to the
standard minimal Gaussian wave packets corresponding to the non-relativistic
dispersion relation , analytic calculations are presented for
the spreading of wave packets with minimal position-velocity uncertainty
product for the lattice dispersion relation as well
as for the relativistic dispersion relation . The
boost properties of moving relativistic wave packets as well as the propagation
of wave packets in an expanding Universe are also discussed
Development and implementation of blood pressure screening and referral guidelines for German community pharmacists.
Involvement of community pharmacists in the detection and control of hypertension improves patient care. However, current European or North-American guidelines do not provide specific guidance how to implement collaboration between pharmacists and physicians, especially when and how to refer patients with undetected or uncontrolled hypertension to a physician. The German Society of Cardiology and the ABDA - Federal Union of German Associations of Pharmacists developed and tested referral recommendations for community pharmacists, embedded in two guideline worksheets. The project included a guideline-directed blood pressure (BP) measurement and recommendations when patients should be referred to their physician. A "red flag" referral within 4 weeks was recommended when SBP was >140 mm Hg or DBP >90 mm Hg (for subjects 160 mm Hg or >90 mm Hg (≥80 years) in undetected individuals, or >130 mm Hg or >80 mm Hg (140 mm Hg or >80 mm Hg (≥65 years) in treated patients. BP was measured in 187 individuals (86 with known hypertension, mean [±SD] age 62 ± 15 years, 64% female, and 101 without known hypertension, 47 ± 16 years, 75% female) from 17 community pharmacies. In patients with hypertension, poorly controlled BP was detected in 55% (n = 47) and were referred. A total of 16/101 subjects without a history of hypertension were referred to their physician because of uncontrolled BP. Structured BP testing in pharmacies identified a significant number of subjects with undetected/undiagnosed hypertension and patients with poorly controlled BP. Community pharmacists could play a significant role in collaboration with physicians to improve the management of hypertension
Facilitating the registration of biocontrol organisms, plant extracts and semiochemicals in Europe
The legal regulation of plant protection products (Dir. 91/414/ EEC) is a bottleneck in the market introduction of new microbial biocontrol agents, plant extracts and pheromones. In contrast, invertebrate biocontrol agents (“beneficials”) are not registered at EU level.
The EU-funded project REBECA suggested improvements to accelerate the regulation process and make it more cost-effective, without compromises to the level of safety. Representatives of all stakeholder groups participated in the REBECA workshops. The EU Commission and Member States are encouraged to improve the registration of biocontrol organisms, plant extracts and semiochemicals at EU and/or national level.
The full proposals can be found at www.rebeca-net.de
Alterations in vascular function in primary aldosteronism - a cardiovascular magnetic resonance imaging study
Introduction: Excess aldosterone is associated with increased cardiovascular risk. Aldosterone has a permissive effect on vascular fibrosis. Cardiovascular magnetic resonance imaging (CMR) allows study of vascular function by measuring aortic distensibility. We compared aortic distensibility in primary aldosteronism (PA), essential hypertension (EH) and normal controls and explored the relationship between aortic distensibility and pulse wave velocity (PWV).<p></p>
Methods: We studied PA (n=14) and EH (n=33) subjects and age-matched healthy controls (n=17) with CMR, including measurement of aortic distensibility, and measured PWV using applanation tonometry. At recruitment, PA and EH patients had similar blood pressure and left ventricular mass.<p></p>
Results: Subjects with PA had significantly lower aortic distensibilty and higher PWV compared to EH and healthy controls. These changes were independent of other factors associated with reduced aortic distensibility, including aging. There was a significant relationship between increasing aortic stiffness and age in keeping with physical and vascular aging. As expected, aortic distensibility and PWV were closely correlated.<p></p>
Conclusion: These results demonstrate that PA patients display increased arterial stiffness compared to EH, independent of vascular aging. The implication is that aldosterone invokes functional impairment of arterial function. The long-term implications of arterial stiffening in aldosterone excess require further study.<p></p>
Polarization transfer in 4He(\vec{e},e'\vec{p}) and 16O(\vec{e},e'\vec{p}) in a relativistic Glauber model
Polarization-transfer components for 4He(\vec{e},e'\vec{p})3H and
16O(\vec{e},e'\vec{p})15N are computed within the relativistic
multiple-scattering Glauber approximation (RMSGA). The RMSGA framework adopts
relativistic single-particle wave functions and electron-nucleon couplings. The
predictions closely match those of a relativistic plane-wave model indicating
the smallness of the final-state interactions for polarization-transfer
components. Also short-range correlations play a modest role for the studied
observables, as long as small proton missing-momenta are probed in
quasi-elastic kinematics. The predictions with free and various
parameterizations for the medium-modified electromagnetic form factors are
compared to the world data.Comment: 24 pages, 11 figure
Pulsed Feedback Defers Cellular Differentiation
Environmental signals induce diverse cellular differentiation programs. In certain systems, cells defer differentiation for extended time periods after the signal appears, proliferating through multiple rounds of cell division before committing to a new fate. How can cells set a deferral time much longer than the cell cycle? Here we study Bacillus subtilis cells that respond to sudden nutrient limitation with multiple rounds of growth and division before differentiating into spores. A well-characterized genetic circuit controls the concentration and phosphorylation of the master regulator Spo0A, which rises to a critical concentration to initiate sporulation. However, it remains unclear how this circuit enables cells to defer sporulation for multiple cell cycles. Using quantitative time-lapse fluorescence microscopy of Spo0A dynamics in individual cells, we observed pulses of Spo0A phosphorylation at a characteristic cell cycle phase. Pulse amplitudes grew systematically and cell-autonomously over multiple cell cycles leading up to sporulation. This pulse growth required a key positive feedback loop involving the sporulation kinases, without which the deferral of sporulation became ultrasensitive to kinase expression. Thus, deferral is controlled by a pulsed positive feedback loop in which kinase expression is activated by pulses of Spo0A phosphorylation. This pulsed positive feedback architecture provides a more robust mechanism for setting deferral times than constitutive kinase expression. Finally, using mathematical modeling, we show how pulsing and time delays together enable “polyphasic” positive feedback, in which different parts of a feedback loop are active at different times. Polyphasic feedback can enable more accurate tuning of long deferral times. Together, these results suggest that Bacillus subtilis uses a pulsed positive feedback loop to implement a “timer” that operates over timescales much longer than a cell cycle
Measurement of polarization-transfer to bound protons in carbon and its virtuality dependence
We measured the ratio of the transverse to longitudinal
components of polarization transferred from electrons to bound protons in
by the process at the
Mainz Microtron (MAMI). We observed consistent deviations from unity of this
ratio normalized to the free-proton ratio,
, for both -
and -shell knocked out protons, even though they are embedded in averaged
local densities that differ by about a factor of two. The dependence of the
double ratio on proton virtuality is similar to the one for knocked out protons
from and , suggesting a universal behavior.
It further implies no dependence on average local nuclear density
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