Measurement of the B(+) production cross section in pp collisions at sqrt[s]=7 TeV

Measurements of the total and differential cross sections dσ/dp(T)(B) and dσ/dy(B) for B(+) mesons produced in pp collisions at sqrt[s]=7 TeV are presented. The data correspond to an integrated luminosity of 5.8 pb(-1) collected by the CMS experiment operating at the LHC. The exclusive decay B(+)→J/ψK(+), with J/ψ→μ(+)μ(-), is used to detect B(+) mesons and to measure the production cross section as a function of p(T)(B) and y(B). The total cross section for p(T)(B)>5 GeV and |y(B)|<2.4 is measured to be 28.1±2.4±2.0±3.1 μb, where the first uncertainty is statistical, the second is systematic, and the last is from the luminosity measurement.     

197AU,57Fe and121Sb Mössbauer study of gold minerals and ores

A survey of the¹⁹⁷Au Mössbauer spectra of naturally occurring gold species is given. Gold minerals have been studied as natural specimens or as synthetic analogues. Gold impurities have been identified in pyrites and arsenopyrites. An example of the use of¹²¹Sb, and⁵⁷Fe Mössbauer spectroscopy in characterizing gold-bearing ore minerals is given.     

Coherence and self-induced transparency in high-energy hadronic collisions

Two consequences of coherence of mesonic fields have been tested in proton-nucleus collisions. Multiplicity fluctuations measured in finite rapidity intervals are found to obey a Poisson distribution at large rapidities where nuclear transparency occurs. In close analogy to quantum optics we present a quark-parton model in which this link between coherence and transparency is realized via the phenomenon of self-induced transparency.     

Zur Frage der Existenz anomaler Racemate

Zusammenfassung Eines der wenigen Beispiele, bei denen in neuerer Zeit anomale Racemate beschrieben wurden, 1st die Äpfelsäure; sie diente als Studienobjekt.Eine Neubearbeitung des Phasendiagramms ergab, daß DL-Äpfelsäure dimorph ist und Mod. II als stabilisierte Zwischenphase auftritt, so daß in dem System D-Äpfelsäure-L-Äpfelsäure statt der bei Racematdiagrammen üblichen zwei Kristallphasen drei verschiedene Phasen vorliegen. Dadurch wird ein System mit einer homogen schmelzenden (normales Racemat) und zwei inhomogen schmelzenden Verbindungen (anomale Racemate) vorgetäuscht.Es wird die Meinung vertreten, daß keine anomalen Racemate existieren, sondern daß die vermeintlichen Anomalien bei enantiomeren Verbindungen ebenso wie bei anderen Zweistoffsystemen auf Polymorphie und Mischkristallbildung beruhen.

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On the existence of anomalous racemates

Summary Malic acid is one of the few substances in which anomalous racemates have been recently described, and it was the object of this study. A new processing of the phase diagram revealed that DL malic acid is dimorphic and that Mod. II occurs as a stabilized intermediate phase. Instead of the two crystal phases usual in the racemate diagram, three different phases are present in the system D malic acid-L malic acid. A system is thereby simulated with a homogenously melting (normal racemate) and two inhomogenously melting compounds (anomalous racemates).The opinion is expressed that no anomalous racemates exist, but that the supposed anomalies in enantiomeric substances as in other twosubstance systems are based on polymorphism and formation of mixed crystals.

     

Angular distribution of jets produced by heavy primary cosmic-ray nuclei

A statistical method is developed for analyzing the angular distribution of meson jets produced by heavy primary cosmic-ray nuclei, enabling detection and elimination of the proton jet due to evaporation of the residual incident nucleus. The procedure is applied to 50 high-energy collisions of heavy primary nuclei. It is shown that a significant fraction of the heavy primaries produce bi-modal meson jets consistent with the two-centre model.     

Deployment of the encapsulation-dehydration protocol to cryopreserve microalgae held at the Sammlung von Algenkulturen, Universitat Gottingen, Germany

Encapsulation-dehydration was applied to cryopreserve 14 diverse algal strains, representing eukaryotic terrestrial microalgae; of these 12 survived to form cell colonies after recovery from cryostorage. Surviving algae had varying degrees of tolerance to osmotic dehydration and desiccation in this vitrification-based cryoprotective strategy. The extent of algal regrowth was affected by the mode of desiccation (silica gel or air-flow), the duration of evaporative desiccation and exposure to light during early recovery phase. This paper: (i) demonstrates the versatility of the encapsulation/dehydration method to cryopreserve diverse microalgae; (ii) confirms the successful transfer of this cryostorage technology to the Culture Collection of Algae at Gottingen University (SAG); and (iii) recommends encapsulation/dehydration as a feasible alternative to controlled rate cooling for preserving algae held in international culture collections.     

A197Au Mössbauer study of the adsorption of aurocyanide onto activated carbon

The chemical state of gold adsorbed on activated carbon from solutions of KAu(CN)₂ has been studied by¹⁹⁷Au Mössbauer spectroscopy as a function of the pH and concentration of the solution, the loading of the carbon, and the drying conditions of the samples. On freshly prepared specimens Au(CN) ₂ ^? is always the dominant species. Drying leads to the formation of other forms of gold, mainly in samples loaded from strongly acidic media. An oligomeric form of AuCN is, however, also formed when samples loaded at high pH values are dried at temperatures around 100°C.