9,998 research outputs found
Shedding Light on Diatom Photonics by means of Digital Holography
Diatoms are among the dominant phytoplankters in the worl's ocean, and their
external silica investments, resembling artificial photonics crystal, are
expected to play an active role in light manipulation. Digital holography
allowed studying the interaction with light of Coscinodiscus wailesii cell wall
reconstructing the light confinement inside the cell cytoplasm, condition that
is hardly accessible via standard microscopy. The full characterization of the
propagated beam, in terms of quantitative phase and intensity, removed a
long-standing ambiguity about the origin of the light. The data were discussed
in the light of living cell behavior in response to their environment
Photonic band gaps analysis of Thue-Morse multilayers made of porous silicon
Dielectric aperiodic Thue-Morse structures up to 128 layers have
been fabricated by using porous silicon technology. The photonic band gap
properties of Thue-Morse multilayers have been theoretically investigated
by means of the transfer matrix method and the integrated density of states.
The theoretical approach has been compared and discussed with the
reflectivity measurements at variable angles for both the transverse electric
and transverse magnetic polarizations of light. The photonic band gap
regions, wide 70 nm and 90 nm, included between 0 and 30°, have been
observed for the sixth and seventh orders, respectively
Quaternionic Wave Packets
We compare the behavior of a wave packet in the presence of a complex and a
pure quaternionic potential step. This analysis, done for a gaussian
convolution function, sheds new light on the possibility to recognize
quaternionic deviations from standard quantum mechanics.Comment: 9 pages, 1 figur
Delay Time in Quaternionic Quantum Mechanics
In looking for quaternionic violations of quantum mechanics, we discuss the
delay time for pure quaternionic potentials. The study shows in which energy
region it is possible to amplify the difference between quaternionic and
complex quantum mechanics.Comment: 9 pages, 5 figure
SBV regularity for Hamilton-Jacobi equations in
In this paper we study the regularity of viscosity solutions to the following
Hamilton-Jacobi equations In particular, under the
assumption that the Hamiltonian is uniformly convex, we
prove that and belong to the class .Comment: 15 page
TG, FT-IR and NMR characterization of n-C16H34 contaminated alumina and silica after mechanochemical treatment
This paper deals with the application of mechanochemistry to model systems composed of alumina or silica artificially contaminated with n-C16H34. The mechanochemical treatment was carried out by means of a ring mill for times ranging from 10 to 40 h. Thermogravimetry and infrared and nuclear magnetic resonance spectroscopies were used for the characterization of the mechanochemical products. The results have indicated that, in the case of alumina, almost all the contaminant n-C16H34 undergoes a complex oxidative reaction path whose end products are strongly held on the surface. These end products are most likely made of crosslinked, partially oxidized hydrocarbon chains bond to the solid surface via COO− groups. In the case of silica, the hydrocarbon undergoes a different, equally complex reaction path, but to a lower extent. In this case the end products are most probably carbonylic compounds and graphitic carbon. Then, for both solid matrices, the mechanochemical treatment promotes significant modification of the chemical nature of the polluting hydrocarbon with end products much more difficult to remove from the surface. As the systems studied are models of sites contaminated by aliphatic hydrocarbon, the results are worthy of consideration in relation to the mobility of the contaminants in the environment
The octonionic eigenvalue problem
By using a real matrix translation, we propose a coupled eigenvalue problem
for octonionic operators. In view of possible applications in quantum
mechanics, we also discuss the hermiticity of such operators. Previous
difficulties in formulating a consistent octonionic Hilbert space are solved by
using the new coupled eigenvalue problem and introducing an appropriate scalar
product for the probability amplitudes.Comment: 21 page
Functional changes during hospital stay in older patients admitted to an acute care ward : a multicenter observational study
Objectives: Changes in physical performance during hospital stay have rarely been evaluated. In this study, we examined functional changes during hospital stay by assessing both physical performance and activities of daily living. Additionally, we investigated characteristics of older patients associated with meaningful in-hospital improvement in physical performance.
Methods: The CRiteria to assess appropriate Medication use among Elderly complex patients project recruited 1123 patients aged >= 65 years, consecutively admitted to geriatric or internal medicine acute care wards of seven Italian hospitals. We analyzed data from 639 participating participants with a Mini Mental State Examination score >= 18/30. Physical performance was assessed by walking speed and grip strength, and functional status by activities of daily living at hospital admission and at discharge. Meaningful improvement was defined as a measured change of at least 1 standard deviation. Multivariable logistic regression models predicting meaningful improvement, included age, gender, type of admission (through emergency room or elective), and physical performance at admission.
Results: Mean age of the study participants was 79 years (range 65-98), 52% were female. Overall, mean walking speed and grip strength performance improved during hospital stay (walking speed improvement: 0.04 +/- 0.20 m/s, p<0.001; grip strength improvement: 0.43 +/- 5.66 kg, p = 0.001), no significant change was observed in activities of daily living. Patients with poor physical performance at admission had higher odds for in-hospital improvement.
Conclusion: Overall, physical performance measurements show an improvement during hospital stay. The margin for meaningful functional improvement is larger in patients with poor physical function at admission. Nevertheless, most of these patients continue to have poor performance at discharge
Reversible and Irreversible Spacetime Thermodynamics for General Brans-Dicke Theories
We derive the equations of motion for Palatini F(R) gravity by applying an
entropy balance law T dS= \delta Q+\delta N to the local Rindler wedge that can
be constructed at each point of spacetime. Unlike previous results for metric
F(R), there is no bulk viscosity term in the irreversible flux \delta N. Both
theories are equivalent to particular cases of Brans-Dicke scalar-tensor
gravity. We show that the thermodynamical approach can be used ab initio also
for this class of gravitational theories and it is able to provide both the
metric and scalar equations of motion. In this case, the presence of an
additional scalar degree of freedom and the requirement for it to be dynamical
naturally imply a separate contribution from the scalar field to the heat flux
\delta Q. Therefore, the gravitational flux previously associated to a bulk
viscosity term in metric F(R) turns out to be actually part of the reversible
thermodynamics. Hence we conjecture that only the shear viscosity associated
with Hartle-Hawking dissipation should be associated with irreversible
thermodynamics.Comment: 12 pages, 1 figure; v2: minor editing to clarify Section III, fixed
typos; v3: fixed typo
Editorial: water governance in a climate change world: appraising systemic and adaptive effectiveness
and other research outputs Editorial: water governance in a climate change world: appraising systemic and adaptive effectivenes
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