Analytical results for a Fokker-Planck equation in the small noise limit

We present analytical results for the lowest cumulants of a stochastic process described by a Fokker-Planck equation with nonlinear drift. We show that, in the limit of small fluctuations, the mean, the variance and the covariance of the process can be expressed in compact form with the help of the Lambert W function. As an application, we discuss the interplay of noise and nonlinearity far from equilibrium.Comment: 5 pages, 4 figure

Vibrational State Resolved Lifetimes of the Na2 21Σ+u Double Well State

Lifetimes of individual Na2 ro-vibrational levels of the 21Σ + u double well-state have been measured using a delayed photoionization technique. Ground state Na2 produced in a molecular beam is excited resonantly by the doubled output of a pulsed dye laser in the range 333 – 357 nm and then ionized by a 532 nm photon from a time-delayed Nd:YAG laser. By appropriate excitation laser tuning and systematic variation of the probe laser delay, ro-vibrational level resolved lifetimes are obtained for v=25- 49. The double well state lifetime values are found to decrease from about 50 ns at v=25 to about 40 ns near the barrier at around v=33 and then to increase back to about 50 ns at the highest observed level of v= 49. We have also performed lifetime calculations using the Leve8 and Bcont programs by Leroy1 , the latter in a version modified by Brett McGeehan. We find that including only bound-bound transitions, the theoretical lifetime values are too large by a factor of up to 2. Inclusion of pertinent bound-free transitions improves the agreement noticeably. 1 R. J. Le Roy, LEVEL 8.0: A Computer Program for Solving the Radial Schr¨odinger Equation for Bound and Quasibound Levels, University of Waterloo Chemical Physics Research Report CP-663 (2007); see http://leroy.uwaterloo.ca/programs/.

Tita: discovery of carbon monoxide in its atmosphere

The 3-D rotation-vibration band of carbon monoxide was identified in the near-infrared spectrum of Titan. A preliminary mixing ratio of CO/N2 = 0.00006 was determined. This result supports the probable detection of CO2 by Samuelson et al and strengthens possible analogies between the atmosphere of Titan and conditions on the primitive Earth

New optical super-resolution imaging approaches involving DNA nanotechnology

With recent advances in optical super-resolution microscopy, biological structures can be imaged with single-nanometre resolution using visible light. One implementation thereof, DNA-PAINT (Point Accumulation for Imaging in Nano-scale Topography), is based on the highly specific and transient binding of fluorescently labelled oligonucleotides, the "imager strands", to complementary strands with which the targets are labelled, the "docking strands". The imager-docking binding events are detected as fluorescence blinking and can be localised with single-nanometre precision. From the set of localised events a super-resolution image can be assembled. DNA-PAINT has multiple advantages over other imaging methods, e.g. high photon yields resulting in high resolution, a free choice of fluorophores while being effectively free from photobleaching, straightforward implementation on a conventional fluorescence microscope and the possibility of temporally multiplexed and quantitative imaging. In this thesis, a test sample based on functionalised microspheres is developed, which allows for optimisation of various DNA-PAINT imaging parameters and for the characterisation and testing of new variations and modifications of DNA-PAINT. One such method which was developed for this thesis, Quencher-Exchange-PAINT, facilitates temporally multiplexed imaging, which is based on the sequential exchange of imager strands targeting different docking strands. The exchange step is replaced by addition of competitive quencher-strands, allowing for rapid, low-crosstalk imager exchange even in biological samples with limited diffusion. Additionally, Proximity-Dependent PAINT is introduced, which enables the imaging of the nanoscale distribution of protein pairs by interaction of two proximity probes which activates DNA-PAINT type binding. The technique is demonstrated both on the microsphere assay as well as in biological samples. Finally, approaches for enhancing the signal-to-noise ratio are explored

A nonlinear drift which leads to κ\kappa-generalized distributions

We consider a system described by a Fokker-Planck equation with a new type of momentum-dependent drift coefficient which asymptotically decreases as $-1/p$ for a large momentum $p$. It is shown that the steady-state of this system is a $\kappa$-generalized Gaussian distribution, which is a non-Gaussian distribution with a power-law tail.Comment: Submitted to EPJB. 8 pages, 2 figures, dedicated to the proceedings of APFA

Monodeuterated methane in the outer Solar System. Part 3: Its abundance on Titan

The 3 nu 2 band of CH3D has been detected in spectra of Titan recorded at 1.6 microns with the Fourier Transform Spectrometer (FTS) at the 4 m telescope of the Kitt Peak National Observatory (NOAO). We have obtained a value of the CH3D/CH4 mixing ratio of 6.6 (+6.6 or -3.3) x 10 to the -4 from a comparison between the observed Titan spectra and synthetic spectra. This value is approx. 2 times higher than the value measured on Uranus (de Bergh et al. 1986) and approx. 6 times higher than on Jupiter and on Saturn (Courtin et al. 1984; de Bergh et al. 1986). It corresponds to D/H of 1.65 (+1.65 or -0.8) x 10 the -4, nominally 8 times higher than the most commonly accepted value for the protosolar D/H = 2 x 10 to the -5 (Geiss and Reeves 1981). The value we find on Titan for D/H in methane is comparable to the D/H ratio measured in terrestrial H2O

A Note on the Determinants and Consequences of Outsourcing Using German Data

Using German data from the Institute for Employment Research Establishment Panel, this paper constructs two main measures of outsourcing and examines their determinants and consequences for employment. There are some commonalities in the correlates of the two measures of outsourcing, as well as agreement on the absence of adverse employment effects across all industries. For one specification, however, some negative effects are reported for manufacturing industry, balanced by positive effects for the services sector for another. But there are no indications of survival bias. This is because the association between outsourcing and plant closings is predominantly negative, albeit poorly determined.outsourcing, organizational change, employment change, plant closings, value added

A Note on the Determinants and Consequences of Outsourcing Using German Data

Using German data from the Institute for Employment Research Establishment Panel, this paper constructs two main measures of outsourcing and examines their determinants and consequences for employment. There are some commonalities in the correlates of the two measures of outsourcing, as well as agreement on the absence of adverse employment effects across all industries. For one specification, however, some negative effects are reported for manufacturing industry, balanced by positive effects for the services sector for another. But there are no indications of survival bias. This is because the association between outsourcing and plant closings is predominantly negative, albeit poorly determined.outsourcing, organizational change, employment change, plant closings, value added

Critical role of canonical transient receptor potential channel 7 in initiation of seizures

Status epilepticus (SE) is a life-threatening disease that has been recognized since antiquity but still causes over 50,000 deaths annually in the United States. The prevailing view on the pathophysiology of SE is that it is sustained by a loss of normal inhibitory mechanisms of neuronal activity. However, the early process leading to the initiation of SE is not well understood. Here, we show that, as seen in electroencephalograms, SE induced by the muscarinic agonist pilocarpine in mice is preceded by a specific increase in the gamma wave, and genetic ablation of canonical transient receptor potential channel (TRPC) 7 significantly reduces this pilocarpine-induced increase of gamma wave activity, preventing the occurrence of SE. At the cellular level, TRPC7 plays a critical role in the generation of spontaneous epileptiform burst firing in cornu ammonis (CA) 3 pyramidal neurons in brain slices. At the synaptic level, TRPC7 plays a significant role in the long-term potentiation at the CA3 recurrent collateral synapses and Schaffer collateral-CA1 synapses, but not at the mossy fiber-CA3 synapses. Taken together, our data suggest that epileptiform burst firing generated in the CA3 region by activity-dependent enhancement of recurrent collateral synapses may be an early event in the initiation process of SE and that TRPC7 plays a critical role in this cellular event. Our findings reveal that TRPC7 is intimately involved in the initiation of seizures both in vitro and in vivo. To our knowledge, this contribution to initiation of seizures is the first identified functional role for the TRPC7 ion channel.Fil: Phelan, K. D.. University of Arkansas for Medical Sciences; Estados UnidosFil: Shwe, U. T.. University of Arkansas for Medical Sciences; Estados UnidosFil: Abramowitz, J.. National Institute of Environmental Health Sciences; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Birnbaumer, Lutz. National Institute of Environmental Health Sciences; Estados UnidosFil: Zheng, F.. University of Arkansas for Medical Sciences; Estados Unido

The Demand for Labor: An Analysis Using Matched Employer-Employee Data from the German LIAB. Will the High Unskilled Worker Own-Wage Elasticity Please Stand Up?

This paper uses matched employee-employer LIAB data to provide panel estimates of the structure of labor demand in Germany, 1993-2002, distinguishing between highly skilled, skilled, and unskilled labor and between the manufacturing and service sectors. Reflecting current preoccupations, our demand analysis seeks also to accommodate the impact of technology and trade in addition to wages. The bottom-line interests are to provide elasticities of the demand for unskilled (and other) labor that should assist in short-run policy design and to identify the extent of skill biases or otherwise in trade and technology.labor demand, own-wage/cross-wage elasticities, trade, technology and organizational change, linked employee-employer data, panel estimates