Mass spectrometric determination of the composition of the Venus clouds

The instrumentation is analyzed for determining the composition of the clouds on Venus. Direct analysis of the gas phase atmosphere, and the detection of ferrous chloride with a mass spectrometer are dicussed along with the mass analyzer, and the pre-separation of cloud particles from the ambient atmosphere

Induced coherence with and without induced emission

We analyze signal coherence in the setup of Wang, Zou and Mandel, where two optical downconverters have indistinct idler modes. Quantum interference, caused by indistinguishability of paths, has a visibility proportional to the transmission amplitude between idlers. Classical interference, caused by induced emission, may be complete for any finite transmission.Comment: 3 pages, including 2 postscript figure

Lunar lander mass spectrometer Final report

Sputter ion source for lunar lander mass spectromete

Sputtering ion source Final report, 29 Mar. - 30 Sep. 1963

Modified sputtering ion source analyses of solid

Toric rings, inseparability and rigidity

This article provides the basic algebraic background on infinitesimal deformations and presents the proof of the well-known fact that the non-trivial infinitesimal deformations of a $K$-algebra $R$ are parameterized by the elements of cotangent module $T^1(R)$ of $R$. In this article we focus on deformations of toric rings, and give an explicit description of $T^1(R)$ in the case that $R$ is a toric ring. In particular, we are interested in unobstructed deformations which preserve the toric structure. Such deformations we call separations. Toric rings which do not admit any separation are called inseparable. We apply the theory to the edge ring of a finite graph. The coordinate ring of a convex polyomino may be viewed as the edge ring of a special class of bipartite graphs. It is shown that the coordinate ring of any convex polyomino is inseparable. We introduce the concept of semi-rigidity, and give a combinatorial description of the graphs whose edge ring is semi-rigid. The results are applied to show that for $m-k=k=3$, $G_{k,m-k}$ is not rigid while for $m-k\geq k\geq 4$, $G_{k,m-k}$ is rigid. Here $G_{k,m-k}$ is the complete bipartite graph $K_{m-k,k}$ with one edge removed.Comment: 33 pages, chapter 2 of the Book << Multigraded Algebra and Applications>> 2018, Springer International Publishing AG, part of Springer Natur

The method of global R* and its applications

The global R* operation is a powerful method for computing renormalisation group functions. This technique, based on the principle of infrared rearrangement, allows to express all the ultraviolet counterterms in terms of massless propagator integrals. In this talk we present the main features of global R* and its application to the renormalisation of QCD. By combining this approach with the use of the program Forcer for the evaluation of the relevant Feynman integrals, we renormalise for the first time QCD at five loops in covariant gauges.Comment: 10 pages, 6 figures, contribution to the proceedings of the 13th International Symposium on Radiative Corrections (RADCOR 2017

A Door in the Illinois Brick Wall - A Functional Equivalent to the Cost-Plus Contract Exception

In Mid-West Paper Products Co. v. Continental Group, Inc., I the Third Circuit took the position that it would not extend the exception beyond the limited circumstances recognized by the Supreme Court. Accordingly, the court held that the use of passing-on theory is impermissible unless its proponent can show preexisting, fixed-quantity, cost-plus contracts at every level of the distribution chain, with the result that he absorbed the illegal overcharge in its entirety. In In re Beef Industry Antitrust Litigation, however, the Fifth Circuit declared that if the exception is confined to cases involving literal cost-plus contracts, then it is a narrow one indeed. Rejecting such a rigid construction, the court held that the exception is also applicable when allegations of rigid formula pricing by middlemen and structural in elasticity of short term supplies compel recognition of a functional equivalent of the cost-plus contract.\u27 This Recent Development examines the conflict between the circuits in light of the principles underlying the Hanover Shoe--Illinois Brick rule to determine the feasibility and implications of recognizing a functional equivalent to the cost-plus exception

A Program of Photometric Measurements of Solar Irradiance Fluctuations from Ground-based Observations

Photometric observations of the sun have been carried out at the San Fernando Observatory since early 1985. Since 1986, observations have been obtained at two wavelengths in order to separately measure the contributions of sunspots and bright facular to solar irradiance variations. Researchers believe that the contributions of sunspots can be measured to an accuracy of about plus or minus 30 ppm. The effect of faculae is much less certain, with uncertainties in the range of plus or minus 300 ppm. The larger uncertainty for faculae reflects both the greater difficulty in measuring the facular area, due to their lower contrast compared to sunspots, and the greater uncertainty in their contrast variation with viewing angle on the solar disk. Recent results from two separate photometric telescopes will be compared with bolometric observations from the active cavity radiometer irradiance monitor (ACRIM) that was on board the Solar Max satellite

From quality control to neurodegeneration : regulation of autophagy and the DNA damage response by ubiquitin-modifying enzymes

Protein homeostasis and genome integrity are safeguarded by a variety of cellular quality control pathways. While protein quality is controlled by a delicate balance between protein biosynthesis, folding and degradation, the DNA is subject to tightly regulated surveillance processes that sense, signal and repair DNA lesions. Many of these processes are regulated by the conjugation of the small modifier ubiquitin to substrates and effector proteins. A polyglutamine-repeat expansion in the gene encoding the deubiquitylating enzyme ataxin-3 is the underlying cause of the neurodegenerative disorder Machado-Joseph disease. Similar to other polyglutamine disorders, the disease is characterized by intracellular inclusions of the mutant protein. Interestingly, wild-type ataxin-3, which disassembles both K63-linked and K48-linked ubiquitin chains, has been reported to be neuroprotective. By means of its catalytic activity, it suppresses toxic aggregation of polyglutamine proteins, including its own mutant counterpart. Ataxin-3 has further been implicated in cellular pathways that regulate protein quality control, transcription and DNA repair. The work presented in this thesis identified additional functions of ataxin-3 in cellular quality control. In paper I, we identified ataxin-3 as a novel interactor of the ubiquitin-like autophagy proteins LC3C and GABARAP and demonstrated that ataxin-3 is required for efficient autophagic degradation in both the nematode Caenorhabditis elegans and mammalian cells. Loss of ataxin-3 did not only result in aberrant accumulation of autophagic vesicles in mammalian cells but also decreased survival of nematodes upon nutrient deprivation, a condition that relies on functional autophagy for survival, and aggravated the accumulation of protein aggregates and aggregate-related motility defects. In paper II, we engineered an inducible, K63-specific ubiquitin ligase and an associated reference substrate, which allow studying the signaling capacity of K63-linked ubiquitin chains in different cellular contexts. This chain type has frequently been linked to inclusion bodies, autophagic degradation and neurodegeneration. Using a mitochondria-localized substrate, we demonstrate that K63-linked ubiquitylation is sufficient to induce perinuclear clustering of the mitochondria, even in the absence of mitochondrial damage, a phenotype that has previously only been described during clearance of damaged mitochondria by mitophagy. In paper III we identified a novel role for ataxin-3 in the regulation of the cellular response to DNA double-strand breaks. We demonstrate that ataxin-3 is recruited to DNA lesions and consolidates the DNA damage response by preventing premature chromatin-extraction of DNA repair proteins by the SUMO-targeted E3 ubiquitin ligase RNF4. We show that ataxin-3 counteracts RNF4-mediated MDC1-ubiquitylation and chromatin-extraction, promoting recruitment of RNF8 and RNF168 and subsequent damage-induced ubiquitin signaling. Consequently, loss of ataxin-3 impaired recruitment of the repair factors 53BP1 and BRCA1 and therefore both non-homologous end-joining and homologous recombination. Similar to the recruitment of RNF4, recruitment of ataxin-3 to DNA lesions was dependent on damage-induced SUMOylation. In paper IV we show that ataxin-3 recruitment, in contrast to RNF4, additionally depends on DNA damage-induced poly(ADP-ribos)ylation, thereby restricting the actions of ataxin-3 to the early phase of the DNA damage response. Differential recruitment of ataxin-3 and RNF4 to DNA double-strand breaks thereby promotes the sequential actions of these enzymes on shared substrates and explains how both proteins promote efficient DNA repair despite their opposing activities. Collectively, the studies presented in this thesis corroborate the importance of ataxin-3 for maintaining genome and protein quality control and furthermore underline the importance of considering the homeostatic functions of wild-type ataxin-3 in the design of therapeutic strategies for Machado-Joseph disease. Additionally, the data presented in this thesis demonstrate the significance of K63-linked ubiquitylation in mediating mitochondrial clustering, not unlike its function in inclusion body formation, and provide a tool to further study the cellular function of these ubiquitin chains