Skeleton as a probe of the cosmic web: the 2D case

We discuss the skeleton as a probe of the filamentary structures of a 2D random field. It can be defined for a smooth field as the ensemble of pairs of field lines departing from saddle points, initially aligned with the major axis of local curvature and connecting them to local maxima. This definition is thus non local and makes analytical predictions difficult, so we propose a local approximation: the local skeleton is given by the set of points where the gradient is aligned with the local curvature major axis and where the second component of the local curvature is negative. We perform a statistical analysis of the length of the total local skeleton, chosen for simplicity as the set of all points of space where the gradient is either parallel or orthogonal to the main curvature axis. In all our numerical experiments, which include Gaussian and various non Gaussian realizations such as \chi^2 fields and Zel'dovich maps, the differential length is found within a normalization factor to be very close to the probability distribution function of the smoothed field. This is in fact explicitly demonstrated in the Gaussian case. This result might be discouraging for using the skeleton as a probe of non Gausiannity, but our analyses assume that the total length of the skeleton is a free, adjustable parameter. This total length could in fact be used to constrain cosmological models, in CMB maps but also in 3D galaxy catalogs, where it estimates the total length of filaments in the Universe. Making the link with other works, we also show how the skeleton can be used to study the dynamics of large scale structure.Comment: 15 pages, 11 figures, submitted to MNRA

Far infrared properties of the rare-earth scandate DyScO3

We present reflectance measurements in the infrared region on a single crystal the rare earth scandate DyScO3. Measurements performed between room temperature and 10 K allow to determine the frequency of the infrared-active phonons, never investigated experimentally, and to get information on their temperature dependence. A comparison with the phonon peak frequency resulting from ab-initio computations is also provided. We finally report detailed data on the frequency dependence of the complex refractive index of DyScO3 in the terahertz region, which is important in the analysis of terahertz measurements on thin films deposited on DyScO3

First detection of NHD and ND2_2 in the interstellar medium

Deuterium fractionation processes in the interstellar medium (ISM) have been shown to be highly efficient in the family of nitrogen hydrides. To date, observations were limited to ammonia (NH$_2$D, NHD$_2$, ND$_3$) and imidogen radical (ND) isotopologues. We want to explore the high frequency windows offered by the \emph{Herschel Space Observatory} to search for deuterated forms of amidogen radical NH$_2$ and to compare the observations against the predictions of our comprehensive gas-grain chemical model. Making use of the new molecular spectroscopy data recently obtained at high frequencies for NHD and ND$_2$, both isotopologues have been searched for in the spectral survey towards the class 0 IRAS 16293-2422, a source in which NH$_3$, NH and their deuterated variants have been previously detected. We used the observations carried out with HIFI (Heterodyne Instrument for the Far Infrared) in the framework of the key program "Chemical Herschel surveys of star forming regions" (CHESS). We report the first detection of interstellar NHD and ND$_2$. Both species are observed in absorption against the continuum of the protostar. From the analysis of their hyperfine structure, accurate excitation temperature and column density values have been determined. The latter were combined with the column density of the parent species NH$_2$ to derive the deuterium fractionation in amidogen. The amidogen D/H ratio measured in the low-mass protostar IRAS 16293-2422 is comparable to the one derived for the related species imidogen and much higher than that observed for ammonia. Additional observations of these species will give more insights into the mechanism of ammonia formation and deuteration in the ISM. We finally indicate the current possibilities to further explore these species at submillimeter wavelengths.Comment: 11 pages, 5 figures, 7 tables. Accepted for publication in A&

Mono Acyl Glycerol Compound Synthesis Through Partial Transesterification Of Castor Oil (Ricinus communis L.) using KOH as Catalyst

It has been done a study of mono acyl glycerol compound synthesis through partial transesterification of castor oil (Ricinus communis L.) using KOH as catalyst. The product of mono acyl glycerol obtained is 45.4 % with the ratio between castor oil triglyceride and methanol 1:2 at 35 0C temperature with the amount of catalyst 0.5 % (b/b) from the reactant total weight and the reaction time 30 minutes. In this research, it was done a compound characterization using, TLC, FTIR and LC MS to prove the success of targeting compound has been synthesized

Fast, exact CMB power spectrum estimation for a certain class of observational strategies

We describe a class of observational strategies for probing the anisotropies in the cosmic microwave background (CMB) where the instrument scans on rings which can be combined into an n-torus, the {\em ring torus}. This class has the remarkable property that it allows exact maximum likelihood power spectrum estimation in of order $N^2$ operations (if the size of the data set is $N$) under circumstances which would previously have made this analysis intractable: correlated receiver noise, arbitrary asymmetric beam shapes and far side lobes, non-uniform distribution of integration time on the sky and partial sky coverage. This ease of computation gives us an important theoretical tool for understanding the impact of instrumental effects on CMB observables and hence for the design and analysis of the CMB observations of the future. There are members of this class which closely approximate the MAP and Planck satellite missions. We present a numerical example where we apply our ring torus methods to a simulated data set from a CMB mission covering a 20 degree patch on the sky to compute the maximum likelihood estimate of the power spectrum $C_\ell$ with unprecedented efficiency.Comment: RevTeX, 14 pages, 5 figures. A full resolution version of Figure 1 and additional materials are at http://feynman.princeton.edu/~bwandelt/RT

Specificity and sensitivity evaluation of novel and existing Bacteroidales and Bifidobacteria-specific PCR assays on feces and sewage samples and their application for microbial source tracking in Ireland

Three novel ruminant-specific PCR assays, an existing ruminant-specific PCR assay and five existing human-specific PCR assays, which target 16S rDNA from Bacteroidales or Bifidobacteria, were evaluated. The assays were tested on DNA extracted from ruminant (n = 74), human (n = 59) and non-ruminant animal (n = 44) sewage/fecal samples collected in Ireland. The three novel PCR assays compared favourably to the existing ruminant-specific assay, exhibiting sensitivities of 91 - 100% and specificities of 95 - 100% as compared to a sensitivity of 95% and specificity of 94%, for the existing ruminant-specific assay. Of the five human-specific PCR assays, the assay targeting the Bifidobacterium catenulatum group was the most promising, exhibiting a sensitivity of 100% (with human sewage samples) and a specificity of 87%. When tested on rural water samples that were naturally contaminated by ruminant feces, the three novel PCR assays tested positive with a much greater percentage (52 - 87%) of samples than the existing ruminant-specific assay (17%). These novel ruminant-specific assays show promise for microbial source tracking and merit further field testing and specificity evaluation.ERTD

资本主义的多样性

法国、意大利、荷兰、中国、阿根廷——其贯穿于19世纪的资本主义制度的历史都有其迷人的特别之处，尽管在这篇短文中，我们关注的是英国、美国、德国和日本，这四个国家是有关“莱茵河与盎格鲁—萨克逊资本主义”争论的中心，在其所有简化形式上，这些争论却都涉及到了福利和经济效率的核心问题。回顾一下上个世纪，这些国家的演进到底意味着怎样一种模式呢？当全球化的压力无情地迫使很多国家放弃了深深地根植于其民族文化的习惯时，这是一种渐进的趋同么？这还不是事情的全部，既然可以证明日本和德国的制度与美国在20世纪20年代而不是今天的制度更加相似，那么，国家干预经济的信仰作为20世纪的一个主要的异端学说，这个思潮的起起落落（在不同的国家以不同的速度）会有良好的效果么？（20世纪60年代“混合经济”的观点仅仅是对苏维埃式的计划经济的苍白反思么？）回答几乎是否定的，因为日本经济的许多明显的特征与这个国家没有多大关系。要不，这向我们讲述了一种根深蒂固的文化保持顽固不化的故事么？回答也几乎是否定的，因为制度的演进（而且，在日本和德国还有巨大的制度飞跃）是所有这四个国家共有的一个特征。进而，它显示了一种盛衰变化律？在20世纪60年代，这些国家都有朝管理型资本主义发展的明显趋同，接着在20世纪80年代，当日益上升的自由市场的力量和机构投资者不断增加的权力产生了改革性的影响，一些国家——主要是在一些盎格鲁—萨克逊国家——的发展又重新分道扬镳。接下来到了20世纪90年代，随着市场的力量和投资者变得更具全球性，并且增加了对日本和德国的影响，趋同会再一次发生么？这是一个可能的解释。通过回顾这段具体的兴衰史，人们也许希望就趋同到底会达到什么程度得出一个合理的估计，因为这毕竟是下个世纪历史的一个关键的决定因素。我们确实没有得出一个有把握的预测，也许读者能够做到这一点。译者单位：东北财经大学经济学院（116025）