5,117 research outputs found
2020 Global food outlook
This report shows just how, and how much, certain policy decisions and social changes will affect the world's future food security. It projects the likely food situation in 2020 if the world continues on more or less its present course, and it then shows how alternative choices could produce a different future. Even rather small changes in agricultural and development policies and investments, it turns out, can have wide-reaching effects on the number of poor and undernourished people around the world. A world of less poverty, greater food security, and a healthier environment is possible, but it will not come about without explicit policy steps in that direction. 2020 Global Food Outlook is the latest in a series of world food projections based on a model developed at IFPRI beginning in 1992.The model has been updated and expanded periodically since then as a way of painting an ever-clearer picture of the global food situation in 2020.
Unconventional Magnetization below 25 K in Nitrogen-doped Diamond provides hints for the existence of Superconductivity and Superparamagnetism
The magnetization of nitrogen-doped single crystalline diamond bulk samples shows unconventional field and temperature hysteresis loops at T ≲ 25 K. The results suggest the existence of superparamagnetic and superconducting regions in samples with nitrogen concentration <200 ppm. Both phases vanish at temperatures above 25 K where the samples show diamagnetic behavior similar to undoped diamond. The observation of superparamagnetism and superconductivity is attributed to the nitrogen doping and to the existence of defective regions. From particle-induced X-ray emission with ppm resolution we rule out that the main observations below 25 K are due to magnetic impurities. We investigated also the magnetic properties of ferromagnetic/high-temperature superconducting oxide bilayers. The magnetization results obtained from those bilayers show remarkable similarities to the ones in nitrogen-doped diamond
Imaging-documented repeated intratumoral hemorrhage in vestibular schwannoma: a case report
Intratumoral hemorrhage in vestibular schwannomas is rare. Symptoms often have an acute onset and include headache, nausea, vomiting, vertigo, and depressed consciousness. Intratumoral hemorrhage is probably caused by vascular fragility associated with tumor characteristics and growth. With hemorrhage in VS being rare, repeated hemorrhage has only been reported twice, and on clinical grounds only. The present report details the case of acute neurological deterioration in a patient with repeated intratumoral hemorrhage inside a vestibular schwannoma with computed tomography and magnetic resonance imaging confirmation. To our knowledge, repeated hemorrhage in vestibular schwannoma with radiological confirmation has not been reported before
Anisotropic and strong negative magneto-resistance in the three-dimensional topological insulator Bi2Se3
We report on high-field angle-dependent magneto-transport measurements on
epitaxial thin films of Bi2Se3, a three-dimensional topological insulator. At
low temperature, we observe quantum oscillations that demonstrate the
simultaneous presence of bulk and surface carriers. The magneto- resistance of
Bi2Se3 is found to be highly anisotropic. In the presence of a parallel
electric and magnetic field, we observe a strong negative longitudinal
magneto-resistance that has been consid- ered as a smoking-gun for the presence
of chiral fermions in a certain class of semi-metals due to the so-called axial
anomaly. Its observation in a three-dimensional topological insulator implies
that the axial anomaly may be in fact a far more generic phenomenon than
originally thought.Comment: 6 pages, 4 figure
Device for doubling the frequency of a light wave comprising a non-linear optical compound
The invention relates to a nonlinear optical medium and a device comprising such a nonlinear optical medium which can be suitably used to double the frequency of red light, while forming blue light. The nonlinear optical medium comprises a polymer matrix and nonlinear optical compounds which contain a substituted sulphone group as the electron-acceptor group
Nonlinear optical compound, nonlinear optical medium, method of manufacturing a nonlinear optical medium and device for doubling the frequency of a light wave
The invention relates to a nonlinear optical medium and a device comprising such a nonlinear optical medium which can be suitably used to double the frequency of red light, while forming blue light. The nonlinear optical medium comprises a polymer matrix and nonlinear optical compounds which contain a substituted sulphone group as the electron-acceptor group
Device for doubling the frequency of a light wave comprising a non-linear optical compound
The invention relates to a nonlinear optical medium and a device comprising such a nonlinear optical medium which can be suitably used to double the frequency of red light, while forming blue light. The nonlinear optical medium comprises a polymer matrix and nonlinear optical compounds which contain a substituted sulphone group as the electron-acceptor group
Study of the Negative Magneto-Resistance of Single Proton-Implanted Lithium-Doped ZnO Microwires
The magneto-transport properties of single proton-implanted ZnO and of
Li(7\%)-doped ZnO microwires have been studied. The as-grown microwires were
highly insulating and not magnetic. After proton implantation the Li(7\%) doped
ZnO microwires showed a non monotonous behavior of the negative
magneto-resistance (MR) at temperature above 150 K. This is in contrast to the
monotonous NMR observed below 50 K for proton-implanted ZnO. The observed
difference in the transport properties of the wires is related to the amount of
stable Zn vacancies created at the near surface region by the proton
implantation and Li doping. The magnetic field dependence of the resistance
might be explained by the formation of a magnetic/non magnetic heterostructure
in the wire after proton implantation.Comment: 6 pages with 5 figure
Nonlinear optical compound, nonlinear optical medium, method of manufacturing a nonlinear optical medium and device for doubling the frequency of a light wave
The invention relates to a nonlinear optical medium and a device comprising such a nonlinear optical medium which can be suitably used to double the frequency of red light, while forming blue light. The nonlinear optical medium comprises a polymer matrix and nonlinear optical compounds which contain a substituted sulphone group as the electron-acceptor group
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