Frequency shifts in stimulated Raman scattering

The nonresonant contributions to the nonlinear susceptibility χ(3) produce a frequency chirp during stimulated Raman scattering. In the case of transient stimulated Raman scattering, the spectrum of the generated Stokes pulse is found at higher frequencies than expected from spontaneous Raman data. The frequency difference can be calculated from the theory of stimulated Raman scattering

Celiac disease

Celiac disease is a chronic intestinal disease caused by intolerance to gluten. It is characterized by immune-mediated enteropathy, associated with maldigestion and malabsorption of most nutrients and vitamins. In predisposed individuals, the ingestion of gluten-containing food such as wheat and rye induces a flat jejunal mucosa with infiltration of lymphocytes. The main symptoms are: stomach pain, gas, and bloating, diarrhea, weight loss, anemia, edema, bone or joint pain. Prevalence for clinically overt celiac disease varies from 1:270 in Finland to 1:5000 in North America. Since celiac disease can be asymptomatic, most subjects are not diagnosed or they can present with atypical symptoms. Furthermore, severe inflammation of the small bowel can be present without any gastrointestinal symptoms. The diagnosis should be made early since celiac disease causes growth retardation in untreated children and atypical symptoms like infertility or neurological symptoms. Diagnosis requires endoscopy with jejunal biopsy. In addition, tissue-transglutaminase antibodies are important to confirm the diagnosis since there are other diseases which can mimic celiac disease. The exact cause of celiac disease is unknown but is thought to be primarily immune mediated (tissue-transglutaminase autoantigen); often the disease is inherited. Management consists in life long withdrawal of dietary gluten, which leads to significant clinical and histological improvement. However, complete normalization of histology can take years

Fully Chlorinated N-Silyl Amides of Titanium and Tungsten

The reaction of hexachlorodisilazanyllithium (Cl3Si)2NLi (1), with TiCl4 leads selectively to the novel fully chlorinated amides (Cl3Si)2NTiCl3 (2) or [(Cl3Si)2N]2 TiCl2 (3), respectively, depending on the molar ratio of the starting materials. The analogous reaction of 1 with WCl6 yielded the amide imide Cl3SiNW(Cl3)N(SiCl3)2 (5) by elimination of SiCl4. The relative amounts of the starting materials had no effect on the formation of 5. 14/15N- and 29Si-NMR data on the starting materials and products show significantly different effects, when compared with those of analogous N-trimethylsilyl derivatives, due to the lower energy of the electrons in the NSi and NM ß bonds. The crystal structure of 5 (triclinic, space group P1) was determined by X-ray structure analysis

Overcoming loss of contrast in atom interferometry due to gravity gradients

Long-time atom interferometry is instrumental to various high-precision measurements of fundamental physical properties, including tests of the equivalence principle. Due to rotations and gravity gradients, the classical trajectories characterizing the motion of the wave packets for the two branches of the interferometer do not close in phase space, an effect which increases significantly with the interferometer time. The relative displacement between the interfering wave packets in such open interferometers leads to a fringe pattern in the density profile at each exit port and a loss of contrast in the oscillations of the integrated particle number as a function of the phase shift. Paying particular attention to gravity gradients, we present a simple mitigation strategy involving small changes in the timing of the laser pulses which is very easy to implement. A useful representation-free description of the state evolution in an atom interferometer is introduced and employed to analyze the loss of contrast and mitigation strategy in the general case. (As a by-product, a remarkably compact derivation of the phase-shift in a general light-pulse atom interferometer is provided.) Furthermore, exact results are obtained for (pure and mixed) Gaussian states which allow a simple interpretation in terms of the alignment of Wigner functions in phase-space. Analytical results are also obtained for expanding Bose-Einstein condensates within the time-dependent Thomas-Fermi approximation. Finally, a combined strategy for rotations and nonaligned gravity gradients is considered as well.Comment: 14+7 pages including appendices, 9 figures; v2 minor changes, matches published versio

Tax Privileges for Families in an International Comparison

Familienleistungsausgleich, Lastenausgleich, Familienpolitik, Welt, Family benefits, Property loss compensation, Family policy, World

Equity as a Prerequisite for Stable Cooperation in a Public-Good Economy - The Core Revisited

In this paper we explore the relationship between an equitable distribution of the cost shares in public-good provision on the one hand and the core property of an allocation on the other. In particular we show that it is an inhomogeneous distribution of cost shares that motivates some coalition of agents to separate and to block an initially given Pareto optimal allocation which can be interpreted as the outcome of a negotiation process when all agents form a grand coalition. Distributional equity of the individual burdens of public-good contribution is assessed by a specific sacrifice measure (the “Moulin sacrifice”) which is derived from the egalitarian-equivalent concept suggested by Moulin (1987). We also develop a simple core test by which it can be checked whether a given allocation is in the core thus being a possible outcome of a cooperative agreement in the public-good economy.public goods, core, equity, stability of cooperation