Accuracy of vertical deflection determination by present-day inertial instrumentation

An analysis of results obtained in the Canadian Rock Mountains indicates that the observation of deflection differences along the same line can be repeated with a precision of about 0.5 sec but that there are systematic discrepancies between the forward and the backward running of the same line. A comparison with the available astronomically determined deflections also shows systematic differences of 2 sec and 3 sec. These errors are most likely due to the overshooting of the Kalman procedure at gradient changes. It appears that the software can be altered in such a way that deflection differences between stations, not more than half an hour of travel time apart, can be determined by the inertial system with an accuracy of better than + or - 1 sec

Multipole invariants and non-Gaussianity

We propose a framework for separating the information contained in the CMB multipoles, $a_{\ell m}$, into its algebraically independent components. Thus we cleanly separate information pertaining to the power spectrum, non-Gaussianity and preferred axis effects. The formalism builds upon the recently proposed multipole vectors (Copi, Huterer & Starkman 2003; Schwarz & al 2004; Katz & Weeks 2004), and we elucidate a few features regarding these vectors, namely their lack of statistical independence for a Gaussian random process. In a few cases we explicitly relate our proposed invariants to components of the $n$-point correlation function (power spectrum, bispectrum). We find the invariants' distributions using a mixture of analytical and numerical methods. We also evaluate them for the co-added WMAP first year map

The Multipole Vectors of WMAP, and their frames and invariants

We investigate the Statistical Isotropy and Gaussianity of the CMB fluctuations, using a set of multipole vector functions capable of separating these two issues. In general a multipole is broken into a frame and $2\ell-3$ ordered invariants. The multipole frame is found to be suitably sensitive to galactic cuts. We then apply our method to real WMAP datasets; a coadded masked map, the Internal Linear Combinations map, and Wiener filtered and cleaned maps. Taken as a whole, multipoles in the range $\ell=2-10$ or $\ell=2-20$ show consistency with statistical isotropy, as proved by the Kolmogorov test applied to the frame's Euler angles. This result in {\it not} inconsistent with previous claims for a preferred direction in the sky for $\ell=2,...5$. The multipole invariants also show overall consistency with Gaussianity apart from a few anomalies of limited significance (98%), listed at the end of this paper.Comment: 9 pages. Submitted to MNRA

On the Nature of the Binary Components of RX J0806.3+1527

We present imaging circular polarimetry and near-infrared photometry of the suspected ultra-short period white-dwarf binary RX J0806.3+1527 obtained with the ESO VLT and discuss the implications for a possible magnetic nature of the white dwarf accretor and the constraints derived for the nature of the donor star. Our V-filter data show marginally significant circular polarization with a modulation amplitude of ~0.5% typical for cyclotron emission from an accretion column in a magnetic field of order 10 MG and not compatible with a direct-impact accretor model. The optical to near-infrared flux distribution is well described by a single blackbody with temperature kT_bb = 35000 K and excludes a main-sequence stellar donor unless the binary is located several scale heights above the galactic disk population.Comment: 2 pages including 2 figures. To appear in RevMexAA(SC) Conference Series, Proc. of IAU Colloquium 194 `Compact Binaries in the Galaxy and Beyond', La Paz (Mexico), eds. G. Tovmassian & E. Sio

A framework for modelling kinematic measurements in gravity field applications

To assess the resolution of the local gravity field from kinematic measurements, a state model for motion in the gravity field of the earth is formulated. The resulting set of equations can accommodate gravity gradients, specific force, acceleration, velocity and position as input data and can take into account approximation errors as well as sensor errors

Template fitting and the large-angle CMB anomalies

We investigate two possible explanations for the large-angle anomalies in the Cosmic Microwave Background (CMB): an intrinsically anisotropic model and an inhomogeneous model. We take as an example of the former a Bianchi model (which leaves a spiral pattern in the sky) and of the latter a background model that already contains a non-linear long-wavelength plane wave (leaving a stripy pattern in the sky). We make use of an adaptation of the ``template'' formalism, previously designed to detect galactic foregrounds, to recognize these patterns and produce confidence levels for their detection. The ``corrected'' maps, from which these patterns have been removed, are free of anomalies, in particular their quadrupole and octupole are not planar and their intensities not low. We stress that although the ``template'' detections are not found to be statistically significant they do correct statistically significant anomalies.Comment: 8 pages. MNRAS submitte

Mogućnost da je olovo esencijalni element

Toxicity cannot be used as an argument against the possibility that an element may be essential. An attempt to determine whether or not lead is essential ds therefore being made in our laboratory, using a technique which has been successful in several other cases (tin, vanadium, fluorine, silicon). It consists of the application of ultraclean, more or less trace-element sterile (but not bacteriologically sterile) isolators, and highly purified amino acid diets. All compounds tested are added to the diet. Young rats maintained in the trace-element isolator system develop deficiencies when unidentified essential trace elements are missing from the diet, the most important symptom being lack of growth. Other signs are shagginess of the fur seborrhea, lack of incisor pigmentation, etc. In order to work with lead, an air filter system has been developed which removes not only dust particles, but also aerosols and substances present as vapors. The basal diet contains 53 individual components (21 amino acids, 13 vitamins, sucrose, 2 fats, 3 salts and 13 trace clement compounds). It was difficult to obtain all of these in lead-free form and monitor their lead content. Special problems were encountered with calcium phosphate, certain amino acids and the fats. The basal diet contains approximately 0.2 ppm of the element. In 13 successive experiments, carried out in 1972/73, growth responses were seen when 1.0-2.5 ppm of lead in form of lead subacetate was added to this ration. The growth effects were statistically highly significant, even though they amounted on the average to an increase of less than 20%. Not only lead subacetate but also lead oxide and lead nitrate produced this response. In extended trials aimed at amplifying these initial data we were at first unable to repeat the results. Screening of possible sources of lead in the system showed that extreme caution was indicated. The lead content of plastic bags, used for storing diets, varied greatly, and a labeling tape used for numbering of diets and animal cages contained 0.560/o (56000 ppm) of the element. Elimination of these potential sources of Lead, and continuous monitoring of all plastic components was necessary for the demonstration of the growth promoting effect.Svrha je ovoga rada da se prikažu rezultati istraživanja koji upućuju na mogućnost da je olovo esencijalni element. Do 1957. samo je sedam elemenata bilo smatrano esencijalnim: željezo, jod, bakar, cink, mangan, kobalt i molibden. Od tada je k ovima pridodane još sedam nužno potrebnih elemenata. Prema definiciji esencijalni je element onaj koji prisutan u tragovima. Što su tragovi u današnjim analitičkim mogućnostima, pitanje je konvencije. Olovo ispunjava mnoge od kriterija koji su postavljeni za esencijalne elemente. Činjenica je da se toksičnost ne može uzeti kao kriterij da Ii je neki elemenat esencijalan ili ne jer nema nikakve funkcionalne povezanosti između toksičnosti i esencijalnih bioloških funkcija, kao što to pokazuje slučaj selenija i drugih dokazane esencijalnih elemenata. U istraživanjima eventualne esencijalne uloge olova u organizmu sisavaca primijenjen je postupak kojim je utvrđena esencijalnost selenija. U principu postoji ultračista soba i izolacijski postupak s jedne strane i upotreba ekstremno pročišćenih aminokiselina u ishrani životinja s druge strane. Sva se oprema sastoji od plastike i nigdje nije upotrijebljeno staklo, metal ili guma. Uveden je specijalni filterski sistem kojim se odstranjuju i najsitnije čestice iz atmosfere. U ovakvom sistemu, praktićki jedini izvor kontaminacije životinja elementima u tragovima jest hrana. Hrana je sadržavala 53 pojedinačna sastojka (21 aminokiselinu, 13 vitamina, šećer, 2 vrste masti, 3 soli i 13 spojeva u tragovima). Bazična hrana sadržavala je otprilike 0,2 ppm olova. Za pokus su uzeti štakori čija su legla bila pažljivo kontrolirana, tako da se izbjegne mogućnost akumuliranja esencijalnog elementa, u ovom slučaju olova. U svakom je pokusu bilo 4 do 5 skupina po 6 do 8 životinja. Kontrolne su životinje držane u kavezima uz uobičajene uvjete, i bile su hranjene posebnim hranama s niskim, poznatim sadržajem olova. U toku 28 do 32 dana životinje su vagane i praćeno je njihovo stanje. U 13 uzastopnih pokusa što su provedeni tijekom 1972/73. utvrđen je utjecaj na rast već pri dodavanju hrani 1,0 do 2,5 ppm olova u obliku subacetata. Ovaj učinak na rast bio je statistički značajan, premda porast težine nije bio veći od 20%. Osim olovnog acetata i olovni je oksid pokazao jednak pozitivan učinak na tjelesni prirast. Pri ponavljanim pokusima ovaj je učinak izostao, ali je naknadno utvrđeno da je tome bila uzrok kontaminacija temeljne hrane olovom iz plastičnih vreća u kojima je hrana držana. Rezultati pokazuju da je vjerojatna potreba štakora za olovom u opisanim uvjetima otprilike 1 ppm u hrani, a to je ona količina koju organizam prima u normalnim uvjetima prehrane

An investigation on the relationship between the user model and graphic representations for the automated generation of multimedia presentations.

This thesis investigates a possible solution to adapting an automatically generated presentation to an anonymous user. We will explore the field of User Modeling, specifically Adaptive Hypermedia, to find suitable methods. In our case study, we combine the methods we find to develop a concept for generating user-adapted multimedia presentations about the virtual collection of the Rijksmuseum of Amsterdam in their websit

Secretion and assembly of functional mini-cellulosomes from synthetic chromosomal operons in Clostridium acetobutylicum ATCC 824.

Background: Consolidated bioprocessing (CBP) is reliant on the simultaneous enzyme production, saccharification of biomass, and fermentation of released sugars into valuable products such as butanol. Clostridial species that produce butanol are, however, unable to grow on crystalline cellulose. In contrast, those saccharolytic species that produce predominantly ethanol, such as Clostridium thermocellum and Clostridium cellulolyticum, degrade crystalline cellulose with high efficiency due to their possession of a multienzyme complex termed the cellulosome. This has led to studies directed at endowing butanol-producing species with the genetic potential to produce a cellulosome, albeit by localising the necessary transgenes to unstable autonomous plasmids. Here we have explored the potential of our previously described Allele-Coupled Exchange (ACE) technology for creating strains of the butanol producing species Clostridium acetobutylicum in which the genes encoding the various cellulosome components are stably integrated into the genome. Results: We used BioBrick2 (BB2) standardised parts to assemble a range of synthetic genes encoding C. thermocellum cellulosomal scaffoldin proteins (CipA variants) and glycoside hydrolases (GHs, Cel8A, Cel9B, Cel48S and Cel9K) as well as synthetic cellulosomal operons that direct the synthesis of Cel8A, Cel9B and a truncated form of CipA. All synthetic genes and operons were integrated into the C. acetobutylicum genome using the recently developed ACE technology. Heterologous protein expression levels and mini-cellulosome self-assembly were assayed by western blot and native PAGE analysis. Conclusions: We demonstrate the successful expression, secretion and self-assembly of cellulosomal subunits by the recombinant C. acetobutylicum strains, providing a platform for the construction of novel cellulosomes. © 2013 Kovács et al.; licensee BioMed Central Ltd