Investigation of slowing down and charge-exchange of nickel and uranium ions in gases and solids in the energy range (60 - 200) MeV/u

In this thesis new slowing down and charge-state measurements will be presented in the energy range of (60 - 200) MeV/u. These measurements were done using the Fragment Separator (FRS) facility at GSI in Darmstadt. The presented data were taken during two experimental runs. The experiments were divided into two parts. In the first part a 200 MeV/u Ni27+ beam was used. The evolution of charge states as a function of the target thickness was investigated covering both the non-equilibrium and equilibrium region. This was done with various mono-atomic materials (Z2 = 6, 7, 10, 13, 18, 22) and compound materials (ethylene, polyethylene and polypropylene). From the measured charge-state distributions the one-electron ionization and capture cross sections have been extracted. A 40 % gas-solid difference is observed in the ionization cross sections for the mono-atomic materials. In the compound materials a 30 % difference is observed between ethylene and the polymers. The experimental cross sections for the mono-atomic materials have been compared with theoretical calculations [1, 2]. The theoretical ionization cross sections agree quite well with the corresponding experimental ionization cross sections. In the gaseous targets the agreement between experiment and theory is better than 3 %. For the capture cross sections the agreement between experiment and theory is also very good for the lighter target materials (Z2 <= 7). For the heavier targets large deviations up to one order of magnitude are observed. These deviations are due to the increasing importance of the non-radiative capture channel in heavier target materials which is quite difficult to calculate accurately. The results motivate for further refinement of the theory in this energy region. In the second part 3 different uranium beams were used with initial energies of 61 MeV/u (U86+ incident), 85 MeV/u (U73+ incoming) and 200 MeV/u (U81+ incident) to measure the evolution of the charge states again and the energy loss as a function of the target thickness in the same materials as used in the first part plus some additional mono-atomic materials Z2 = 29, 36, 47, 54. From the measured charge-state distributions and energy losses the mean charges and stopping forces have been extracted. At 61 MeV/u we observe a gas-solid difference in the mean charge of up to 4 charge states for the mono-atomic materials. The corresponding stopping powers (forces) at the same specific energy only show a gas-solid difference for light materials (Z2 <= 7). The stopping forces are compared with calculations done with the PASS code [3, 4], ATIMA code [5] and the Hubert et al. tables [6]. The agreement is quite good between experiment and theory. The PASS code predicts by using the experimental mean charges a gas-solid difference in the stopping force for the heavier target materials. In the data at 200 MeV/u there is a gas-solid difference in the ionization rate for U81+ ions similar to the Ni27+ results.In dieser Dissertation werden neue Ladungsverteilungen und Energieverlustmessungen präsentiert. Diese Messungen wurden am Fragment Separator (FRS) bei der GSI in Darmstadt durchgeführt. Die Daten, die hier vorgestellt werden, wurden in zwei Experimenten aufgenommen. Die Experimente bestanden aus zwei Teilen. Im ersten Teil wurde mit einem 200 MeV/u Ni27+ Strahl gemessen. Ziel dieser Messung war die Entwicklung der Ladungsverteilung als Funktion der Targetdicke vom Nichtgleichgewicht bis Gleichgewicht zu untersuchen. Dies wurde mit verschiedenen Targets gemacht (Z2 = 6, 7, 10, 13, 18, 22, Äthylen, Polyäthylen und Polypropylen). Von den gemessenen Ladungsverteilung konnten die Umladungsquerrschnitte für Elektroneneinfang und -verlust extrahiert werden. Ein Gas-Festkörper Effekt von 40 % wurde im Ionizationsquerrschnitt für die monoatomaren (reinen Elemente) Targets gemessen. Im Äthylen und den Polymeren (Polyäthylen und Polypropylen) war ein Effekt von 30 % zu sehen. Die experimentellen Umladungsquerrschnitte für die monoatomaren Targets wurden mit theoretischen Rechnungen von A. Surzhykov und S. Fritzsche [1] und V. P. Shevelko [2] verglichen. In der Ionization stimmen die theoretischen Rechnungen mit den experimentellen Werten gut überein. In den Gastargets ist die Übereinstimmung besser als 3 %. Im Elektroneneinfang gibt es gute Übereinstimmung zwischen Experiment und Theorie bei den leichten Targets (Z2 <= 7), bei den schweren Targets gibt es grosse Abweichungen bis zu einer Grössenordnung. Diese Abweichung kommt zustande, weil der nicht-radiative Querrschnitt einen grösseren Anteil hat bei den schweren Targets und dieser Teil sehr schwer theoretisch zu rechnen ist. Die Ergebnisse sind eine Motivation für Verbesserungen in der Theorie im diesen Energiebereich. Im zweiten Teil wurde ein Uranstrahl bei drei verschiedenen Energien benutzt, diese waren 61 MeV/u mit 86+ als Eingangsladungszustand, 85 MeV/u mit 73+ als Eingangsladungszustand und 200 MeV/u mit 81+ als Eingangsladungszustand. Ziel dieser Messung war es wiederum, die Entwicklung der Ladungsverteilung zu untersuchen und auch Energieverluste zu messen. Dieselben Targets wurden benutzt und zusätzlich wurden folgende Targets vermessen Z2 = 29, 36, 47, 54. Von den gemessenen Ladungsverteilungen und Energieverlusten wurde die mittlere Ladung und das Bremsvermögen bestimmt. Bei 61 MeV/u ist ein Gas-Festkörper Effekt in der mittleren Ladung bei den monoatomaren Targets zu sehen. Der Effekt hat eine Grösse von fast 4 Ladungen. Das dazu gehörige Bremsvermögen zeigt nur einen Gas-Festkörper Effekt bei den leichteren Targets (Z2 <= 7). Die experimentellen Werte wurden mit dem PASS Programm [3, 4], dem ATIMA Programm [5] und den Hubert et al. Tabellen [6] verglichen. Die theoretischen Rechnungen von den Programmen stimmen mit den experimentellen Werten gut überein. PASS sagt einen Gas-Festkörper Effekt bei den schwereren Targets voraus, weil experimentelle Ladungen als Eingangsparameter benutzt wurden. Bei der 200 MeV/u Messung wurde ein Gas-Festkörper Unterschied in der Ionizationsrate in der Entwicklung des U81+ Ladungszustand beobachtet, ähnlich wie in der Ni27+ Messung

Quantum resource estimates for computing elliptic curve discrete logarithms

We give precise quantum resource estimates for Shor's algorithm to compute discrete logarithms on elliptic curves over prime fields. The estimates are derived from a simulation of a Toffoli gate network for controlled elliptic curve point addition, implemented within the framework of the quantum computing software tool suite LIQ$Ui|\rangle$. We determine circuit implementations for reversible modular arithmetic, including modular addition, multiplication and inversion, as well as reversible elliptic curve point addition. We conclude that elliptic curve discrete logarithms on an elliptic curve defined over an $n$-bit prime field can be computed on a quantum computer with at most $9n + 2\lceil\log_2(n)\rceil+10$ qubits using a quantum circuit of at most $448 n^3 \log_2(n) + 4090 n^3$ Toffoli gates. We are able to classically simulate the Toffoli networks corresponding to the controlled elliptic curve point addition as the core piece of Shor's algorithm for the NIST standard curves P-192, P-224, P-256, P-384 and P-521. Our approach allows gate-level comparisons to recent resource estimates for Shor's factoring algorithm. The results also support estimates given earlier by Proos and Zalka and indicate that, for current parameters at comparable classical security levels, the number of qubits required to tackle elliptic curves is less than for attacking RSA, suggesting that indeed ECC is an easier target than RSA.Comment: 24 pages, 2 tables, 11 figures. v2: typos fixed and reference added. ASIACRYPT 201

Bilateral dilation of the urinary tract due to iliopsoas pyomyositis: a case report

<p>Abstract</p> <p>Introduction</p> <p>Pyomyositis is an acute bacterial infection of the skeletal muscles that arises from hematogenous spread and is caused predominantly by Gram-positive cocci.</p> <p>Case presentation</p> <p>We report a case of iliopsoas pyomyositis in a 25-year-old Greek Caucasian woman with a history of intravenous drug use. Her condition was complicated by bilateral dilation of the ureters and renal calyces as a result of mechanical pressure from inflammation and edema of the involved muscle. The patient did not present aggravation of renal function and was treated successfully solely with intravenous antibiotics, without surgical intervention. This is the first case report describing iliopsoas pyomyositis with reversible bilateral dilation of the urinary tract that was treated successfully with intravenous antibiotics, without surgical intervention.</p> <p>Conclusion</p> <p>We present the first described case of iliopsoas pyomyositis with reversible bilateral hydroureteronephrosis that was treated successfully with intravenous antibiotics, without the necessity of surgical intervention. To our knowledge, this is the first report of its kind in the literature regarding an unexpected event in the course of treating a patient with iliopsoas pyomyositis, and it should be of particular interest to different clinical medical specialties such as internal medicine, infectious disease and urology.</p

How consistent are the transcriptome changes associated with cold acclimation in two species of the Drosophila virilis group?

This work was financially support by a Marie Curie Initial Training Network grant, “Understanding the evolutionary origin of biological diversity” (ITN-2008–213780 SPECIATION), grants from the Academy of Finland to A.H. (project 132619) and M.K. (projects 268214 and 272927), a grant from NERC, UK to M.G.R. (grant NE/J020818/1), and NERC, UK PhD studentship to D.J.P. (NE/I528634/1).For many organisms the ability to cold acclimate with the onset of seasonal cold has major implications for their fitness. In insects, where this ability is widespread, the physiological changes associated with increased cold tolerance have been well studied. Despite this, little work has been done to trace changes in gene expression during cold acclimation that lead to an increase in cold tolerance. We used an RNA-Seq approach to investigate this in two species of the Drosophila virilis group. We found that the majority of genes that are differentially expressed during cold acclimation differ between the two species. Despite this, the biological processes associated with the differentially expressed genes were broadly similar in the two species. These included: metabolism, cell membrane composition, and circadian rhythms, which are largely consistent with previous work on cold acclimation/cold tolerance. In addition, we also found evidence of the involvement of the rhodopsin pathway in cold acclimation, a pathway that has been recently linked to thermotaxis. Interestingly, we found no evidence of differential expression of stress genes implying that long-term cold acclimation and short-term stress response may have a different physiological basis.PostprintPeer reviewe

Discovery of mating in the major African livestock pathogen Trypanosoma congolense

The protozoan parasite, Trypanosoma congolense, is one of the most economically important pathogens of livestock in Africa and, through its impact on cattle health and productivity, has a significant effect on human health and well being. Despite the importance of this parasite our knowledge of some of the fundamental biological processes is limited. For example, it is unknown whether mating takes place. In this paper we have taken a population genetics based approach to address this question. The availability of genome sequence of the parasite allowed us to identify polymorphic microsatellite markers, which were used to genotype T. congolense isolates from livestock in a discrete geographical area of The Gambia. The data showed a high level of diversity with a large number of distinct genotypes, but a deficit in heterozygotes. Further analysis identified cryptic genetic subdivision into four sub-populations. In one of these, parasite genotypic diversity could only be explained by the occurrence of frequent mating in T. congolense. These data are completely inconsistent with previous suggestions that the parasite expands asexually in the absence of mating. The discovery of mating in this species of trypanosome has significant consequences for the spread of critical traits, such as drug resistance, as well as for fundamental aspects of the biology and epidemiology of this neglected but economically important pathogen

Reaction rates for Neutron Capture Reactions to C-, N- and O-isotopes to the neutron rich side of stability

The reaction rates of neutron capture reactions on light nuclei are important for reliably simulating nucleosynthesis in a variety of stellar scenarios. Neutron capture reaction rates on neutron-rich C-, N-, and O-isotopes are calculated in the framework of a hybrid compound and direct capture model. The results are tabulated and compared with the results of previous calculations as well as with experimental results.Comment: 33 pages (uses revtex) and 9 postscript figures, accepted for publication in Phys. Rev.

Towards Quantum Repeaters with Solid-State Qubits: Spin-Photon Entanglement Generation using Self-Assembled Quantum Dots

In this chapter we review the use of spins in optically-active InAs quantum dots as the key physical building block for constructing a quantum repeater, with a particular focus on recent results demonstrating entanglement between a quantum memory (electron spin qubit) and a flying qubit (polarization- or frequency-encoded photonic qubit). This is a first step towards demonstrating entanglement between distant quantum memories (realized with quantum dots), which in turn is a milestone in the roadmap for building a functional quantum repeater. We also place this experimental work in context by providing an overview of quantum repeaters, their potential uses, and the challenges in implementing them.Comment: 51 pages. Expanded version of a chapter to appear in "Engineering the Atom-Photon Interaction" (Springer-Verlag, 2015; eds. A. Predojevic and M. W. Mitchell

Neutrinos from the Sun: experimental results confronted with solar models

For standard neutrinos, recent solar neutrino results together with the assumption of a nuclearly powered Sun imply severe constraints on the individual components of the total neutrino flux: \Phi_{Be}<0.7*10^9cm^-2 s^-1, \Phi_{CNO}< 0.6*10^9 cm^-2 s^-1, and $64*10^9 cm^-2 s^-1< \Phi_{pp+pep} < 65*10^9 cm^-2 s^-1 (at 1 \sigma level). The bound on \Phi_{Be} is in strong disagreement with the standard solar model prediction \Phi_{Be}^{SSM}\approx 5*10^9 cm^-2 s^-1. We study a large variety of non-standard solar models with low inner temperature, finding that the temperature profiles T(m) follow the homology relationship: T(m)=kT^{SSM}(m), so that they are specified just by the central temperature T_c. There is no value of T_c which can account for all the available experimental results. Even if we only consider the Gallium and Kamiokande results, they remain incompatible. Lowering the cross section p+Be7 \to \gamma+B8 is not a remedy. The shift of the nuclear fusion chain towards the pp-I termination could be induced by a hypothetical low energy resonance in the He3+He3 reaction. This mechanism gives a somehow better, but still bad fit to the combined experimental data. We also discuss what can be learnt from new generation experiments about the properties of neutrinos and of the Sun.Comment: 20 pages in RevTeX 3.0 plus 14 figures in uuencoded postscript file

Cohesive properties of alkali halides

We calculate cohesive properties of LiF, NaF, KF, LiCl, NaCl, and KCl with ab-initio quantum chemical methods. The coupled-cluster approach is used to correct the Hartree-Fock crystal results for correlations and to systematically improve cohesive energies, lattice constants and bulk moduli. After inclusion of correlations, we recover 95-98 % of the total cohesive energies. The lattice constants deviate from experiment by at most 1.1 %, bulk moduli by at most 8 %. We also find good agreement for spectroscopic properties of the corresponding diatomic molecules.Comment: LaTeX, 10 pages, 1 figure, accepted by Phys. Rev.