Experimental determination of cw dye laser parameters by loss variation

The behavior of a cw dye laser under variation of the output coupling has been investigated. By studying the dependence of laser threshold, output power and slope efficiency on the degree of outcoupling, numerical values for macroscopic and microscopic laser parameters have been obtained. The macroscopic data comprise values for internal cavity losses and mode matching conditions, the microscopic data refer to molecular parameters of the dye used, such as cross-sections for stimulated emission and triplet-triplet absorption.     

A bimetric machian approach to gravitation

We propose a bimetric machian approach to gravitation with a mathematical structure much simpler than the one of Rosen's bimetric theories. We obtain two cosmological models based on the simplest assumption that the Universe be filled of pure dust matter. One of the two cosmological models is compatible with the currently observed value of the density of dust matter, and provides an age of the Universe which is of the order of the inverse of the present Hubble parameter. One also obtains the Schwarzschild-like solution and its Newtonian limit together with the modified three Kepler laws which allow us to find that presently 0.5×10^?10 (yr)^?1 δ(A/A)δ 0.625×10^?10 (yr)^?1, a denoting the semimajor axis of the orbit of the test particle. Lastly we obtain the Newtonian limit of the theory.     

Separation of human fibrinopeptides by capillary zone electrophoresis

We describe a method for the simultaneous determination of the five fibrinopeptide forms derived from the thrombin-promoted activation of human fibrinogen by capillary zone electrophoresis (CZE). The fibrinopeptide mixture was first desalted by a solid-phase extraction (SPE) step. The analysis was performed in reversed polarity in a highly cross-linked polyethylene glycol (PEG)-coated capillary with UV-light absorption detection at 200 nm. Several parameters including buffer concentration and pH, presence of an organic modifier, temperature, and applied voltage, have been tested. The best separations were obtained within 20 min, utilizing a 20 mM sodium phosphate buffer without organic modifier, in the narrow 6.1-6.2 pH range, at 25 degrees C, with an applied voltage of 20 kV. Quantitative analysis is made possible by the use of sheep fibrinopeptide A as an internal standard to correct for both extraction and injection errors.     

Origin of arsenic pollution in Southwest Tuscany: comparison of fluvial sediments

The Colline Metallifere in SW Tuscany are characterized by strong anomalies in arsenic concentrations and distribution. The area is sparsely populated and largely wild, though it has been subject to human impact due to mining and metal processing since Etruscan and Roman times. In the Middle Ages it was exploited intensively for silver and copper. Until 1995, pyrite (FeS2) was mined and roasted to produce sulphuric acid and iron. Hypotheses based on geological and mineralogical factors formulated in the last 20 years have failed to explain the peculiar distribution of arsenic in the Colline Metallifere. Here we report preliminary results of widespread sampling and analysis of the fluvial sediments of rivers originating in this mining area. The data was analysed in relation to the archaeological features of the area, since the presence of ancient mining and ore processing sites can shed light on the peculiar distribution of arsenic. Comparison of data from two rivers and their respective contaminated and uncontaminated coastal lagoons also clarified the general mechanisms of arsenic mobility, pinpointing the source of arsenic contamination. The study methods also promise to be useful for discovering unknown archaeological sites.     

A background-dependent approach to the theory of gravitation

On the basis of a Machian view of nature we find a covariant formulation of Newton's gravitational equation in a general frame which satisfies the requirements (i) of being singular if the density of mass is zero everywhere and (ii) of depending on the parallel transport of the four-momentum density of matter (from the three-space point in which it is defined to any other three-space point, at any fixed time) in such a way that it incorporates the idea that the frame has to be fixeddirectly in connection with the distribution and motion of matter. In Paper II we will use such an equation as starting point in order to find relativistic gravitational equations which are supposed to hold in any conceivable universe, describe a purely geometrical theory of gravitation, and explicitly incorporate Mach's principle.     

Brillouin light scattering study of polymeric glassy sulfur

We present here a study of the acoustic dynamics of polymeric glassy sulfur. The data have been collected in the GHz frequency range by means of Brillouin light scattering for different scattering geometries. The choice of the experimental setup allows us to obtain information on the refractive index, n, that comes out to be close to that corresponding to the high temperature polymeric liquid phase. The longitudinal acoustic excitations have been investigated as a function of temperature from deep into the glassy state up to the glass transition temperature. The temperature dependence of the sound velocity is compared to the one measured in the liquid phase. We find that the sound velocity of the glass can be linearly extrapolated from that of the polymeric liquid measured in the THz frequency range with inelastic X-ray scattering.     

Mouse brain expression patterns of <Emphasis Type="Italic">Spg7</Emphasis>, <Emphasis Type="Italic">Afg3l1</Emphasis>, and <Emphasis Type="Italic">Afg3l2</Emphasis> transcripts,encoding for the mitochondrial <Emphasis Type="Italic">m</Emphasis>-AAA protease

Background  

The m-AAA (ATPases Associated with a variety of cellular Activities) is an evolutionary conserved metalloprotease complex located in the internal mitochondrial membrane. In the mouse, it is a hetero-oligomer variably formed by the Spg7, Afg3l1, and Afg3l2 encoded proteins, or a homo-oligomer formed by either Afg3l1 or Afg3l2. In humans, AFG3L2 and SPG7 genes are conserved, whereas AFG3L1 became a pseudogene. Both AFG3L2 and SPG7 are involved in a neurodegenerative disease, namely the autosomal dominant spinocerebellar ataxia SCA28 and a recessive form of spastic paraplegia, respectively.