CARS spectroscopy of the (v=0→1v=0\to1) band in T2\rm{T_2}

Molecular hydrogen is a benchmark system for bound state quantum calculation and tests of quantum electrodynamical effects. While spectroscopic measurements on the stable species have progressively improved over the years, high resolution studies on the radioactive isotopologues $\rm{T_2}$, $\rm{HT}$ and $\rm{DT}$ have been limited. Here we present an accurate determination of $\rm{T_2}$ $Q(J = 0 - 5)$ transition energies in the fundamental vibrational band of the ground electronic state, by means of high resolution Coherent Anti-Stokes Raman Spectroscopy. With the present experimental uncertainty of $0.02\,\rm{cm^{-1}}$, which is a fivefold improvement over previous measurements, agreement with the latest theoretical calculations is demonstrated.Comment: 9 pages, 3 figure

The Semmes Weinstein monofilament examination as a screening tool for diabetic peripheral neuropathy

ObjectiveThe purpose of this systematic review is to evaluate current evidence in the literature on the efficacy of Semmes Weinstein monofilament examination (SWME) in diagnosing diabetic peripheral neuropathy (DPN).MethodsThe PubMed database was searched through August 2008 for articles pertaining to DPN and SWME with no language or publication date restrictions. Studies with original data comparing the diagnostic value of SWME with that of one or more other modalities for DPN in patients with diabetes mellitus were analyzed. Data were extracted by two independent investigators. Diagnostic values were calculated after classifying data by reference test, SWME methodology, and diagnostic threshold.ResultsOf the 764 studies identified, 30 articles were selected, involving 8365 patients. There was great variation in both the reference test and the methodology of SWME. However, current literature suggests that nerve conduction study (NCS) is the gold standard for diagnosing DPN. Four studies were identified which directly compared SWME with NCS and encompassed 1065 patients with, and 52 patients without diabetes mellitus. SWME had a sensitivity ranging from 57% (95% confidence interval [CI], 44% to 68%) to 93% (95% CI, 77% to 99%), specificity ranging from 75% (95% CI, 64% to 84%) to 100% (95% CI, 63% to 100%), positive predictive value (PPV) ranging from 84% (95% CI, 74% to 90%) to 100% (95% CI, 87% to 100%), and negative predictive value (NPV) ranging from 36% (95% CI, 29% to 43%) to 94% (95% CI, 91% to 96%).ConclusionsThere is great variation in the current literature regarding the diagnostic value of SWME as a result of different methodologies. To maximize the diagnostic value of SWME, a three site test involving the plantar aspects of the great toe, the third metatarsal, and the fifth metatarsals should be used. Screening is vital in identifying DPN early, enabling earlier intervention and management to reduce the risk of ulceration and lower extremity amputation

Relativistic and QED effects in the fundamental vibration of T2_2

The hydrogen molecule has become a test ground for quantum electrodynamical calculations in molecules. Expanding beyond studies on stable hydrogenic species to the heavier radioactive tritium-bearing molecules, we report on a measurement of the fundamental T$_2$ vibrational splitting $(v= 0 \rightarrow 1)$ for $J=0-5$ rotational levels. Precision frequency metrology is performed with high-resolution coherent anti-Stokes Raman spectroscopy at an experimental uncertainty of $10-12$~MHz, where sub-Doppler saturation features are exploited for the strongest transition. The achieved accuracy corresponds to a fifty-fold improvement over a previous measurement, and allows for the extraction of relativistic and QED contributions to T$_2$ transition energies.Comment: 5 pages, 5 figure

Optimisation of on-line principal component analysis

Different techniques, used to optimise on-line principal component analysis, are investigated by methods of statistical mechanics. These include local and global optimisation of node-dependent learning-rates which are shown to be very efficient in speeding up the learning process. They are investigated further for gaining insight into the learning rates' time-dependence, which is then employed for devising simple practical methods to improve training performance. Simulations demonstrate the benefit gained from using the new methods.Comment: 10 pages, 5 figure

Sheared bioconvection in a horizontal tube

The recent interest in using microorganisms for biofuels is motivation enough to study bioconvection and cell dispersion in tubes subject to imposed flow. To optimize light and nutrient uptake, many microorganisms swim in directions biased by environmental cues (e.g. phototaxis in algae and chemotaxis in bacteria). Such taxes inevitably lead to accumulations of cells, which, as many microorganisms have a density different to the fluid, can induce hydrodynamic instabilites. The large-scale fluid flow and spectacular patterns that arise are termed bioconvection. However, the extent to which bioconvection is affected or suppressed by an imposed fluid flow, and how bioconvection influences the mean flow profile and cell transport are open questions. This experimental study is the first to address these issues by quantifying the patterns due to suspensions of the gravitactic and gyrotactic green biflagellate alga Chlamydomonas in horizontal tubes subject to an imposed flow. With no flow, the dependence of the dominant pattern wavelength at pattern onset on cell concentration is established for three different tube diameters. For small imposed flows, the vertical plumes of cells are observed merely to bow in the direction of flow. For sufficiently high flow rates, the plumes progressively fragment into piecewise linear diagonal plumes, unexpectedly inclined at constant angles and translating at fixed speeds. The pattern wavelength generally grows with flow rate, with transitions at critical rates that depend on concentration. Even at high imposed flow rates, bioconvection is not wholly suppressed and perturbs the flow field.Comment: 19 pages, 9 figures, published version available at http://iopscience.iop.org/1478-3975/7/4/04600

Das Verhalten von Plasmopara viticola auf resistenten und anfälligen Rebsorten

An Topfreben und Blattscheiben verschiedener resistenter und anfälliger Rebsorten wurde das Verhalten von Plasmopara viticola bei verschiedenen Inokulumdichten, unterschiedlicher Temperatur und Beleuchtung während der Inkubation, sowie veränderter Inkubationsdauer und Blattnässedauer geprüft.Einen starken Einfluß auf die Sporulation des Pilzes auf Blattscheiben hatten die Konzentration des Inokulums sowie die Temperatur und die Belichtung während der Inkubation. Bei diesen Faktoren traten signifikante Interaktionen mit der Sorte auf. Die Dauer der Blattnässe war, soweit sie die für eine Infektion notwendige Dauer nicht unterschritt, ohne Einfluß auf die Sporulation des Pilzes bei verschiedenen Sorten. Ähnliches gilt für die Inkubationsdauer, deren Verlängerung, auch weit über die minimal erforderliche Zeit hinaus, ohne Einfluß auf die Sporulation blieb.The behavior of Plasmopara viticola on resistant and susceptible grapevine varietiesThe behaviour of Plasmopara viticola with respect to inoculum concentration, temperature, level of illumination during incubation, duration of incubation and leaf wetness was investigated with different resistant und susceptible grapevine varieties using leaf discs and potted plants. Inoculum concentration, temperature and illumination during incubation had a great effect on the sporulation of the fungus on leaf discs and proved to be cultivar-dependent. Duration of leaf wetness had no effect on sporulation provided that it was long enough for the infection process to be completed. In a similar way an incubation time longer than that necessary for completion of fungal growth, had no effect on sporulation

A Laterally Modulated 2D Electron System in the Extreme Quantum Limit

We report on magnetotransport of a two-dimensional electron system (2DES), located 32 nm below the surface, with a surface superlattice gate structure of periodicity 39 nm imposing a periodic modulation of its potential. For low Landau level fillings $\nu$, the diagonal resistivity displays a rich pattern of fluctuations, even though the disorder dominates over the periodic modulation. Theoretical arguments based on the combined effects of the long-wavelength, strong disorder and the short-wavelength, weak periodic modulation present in the 2DES qualitatively explain the data.Comment: 4 pages, 5 figures. to appear in Phys. Rev. Let

Wirtsbesiedlung durch Plasmopara viticola bei unterschiedlich anfälligen Wirten

Mit Plasmopara viticola infizierte Blattscheiben von verschieden anfalligen Rebsorten und Rebarten wurden nach 6, 24 und 48 h Inkubation fixiert und mit optischen Aufhellern oder Säurefuchsinlösung gefärbt. Die in den Blattscheiben vorgefundenen Entwicklungsstadien des Erregers wurden quantitativ ausgewertet.Die Resistenz einer Rebsorte hat keinen Einfluß auf die Anlagerung der Zoosporen von P. viticola an ihre Spaltöffnungen. Die ersten Behinderungen der Wirtsbesiedlung an resistenten Arten traten auf, wenn der Keimschlauch des Erregers versucht, in die Atemhöhle einzudringen. Bei den verschiedenen Klonen der Arten Vitis riparia und V. rupestris gelang es P. viticola häufig nicht, in der Atemhöhle sichtbare Strukturen zu bilden. Bei V. riparia und der pilzresistenten Sorte Fr 946-60 wurde die Erregerentwicklung in der Atemhöhle häufig schon vor der Bildung des Primärhaustoriums behindert. Bei den pilzresistenten Sorten Fr 946-60, Fr 993-60, Castor und SV 5-276 wurde der Erreger meist nach der Bildung eines Haustoriums in der weiteren Entwicklung behindert . In diesem Entwicklungsstadium kam es häufig zu Degenerationserscheinungen an der befallenen Wirtszelle. Bei der Sorte Pollux traten diese Behinderungen später, meist nach Bildung des zweiten Haustoriums, auf.Host settlement of Plasmopara viticola on different susceptible hostsLeaf discs of grapevine varieties and species of various resistance to downy mildew were infected by Plasmopara viticola, fixed after 6, 24 and 48 h of incubation and coloured with optical brighteners or fuchsin acid solution. The different stages of infection were investigated qualitatively and quantitatively. Zoospores of P. viticola settled at the stomata of leaves of resistant and susceptible cultivars. The first phenomenon of resistance occurs when the germination tube tries to enter the substomatal hole. In clones of Vitis riparia and V. rupestris germination tubes of the pathogen were frequently hindered to enter the substomatal hole. In V. riparia and the resistant variety Fr 946-60 P. viticola was often already stopped before forming a primary haustorium. In the resistant varieties Fr 946-60, Fr 993-60, Castor and SV 5-276 the pathogen was stopped in many cases after the formation of the first haustorium. At this time degeneration of the parasitized host-cells could often be observed. In the resistant variety Pollux cell degenerations mostly occur after the formation of the secondary haustorium

Open thoracic or thoracoabdominal aortic aneurysm repair after previous abdominal aortic aneurysm surgery

ObjectiveThe purpose of this study was to provide insight into the incidence of thoracic and thoracoabdominal aortic aneurysm repair following previous infrarenal abdominal aortic aneurysm (AAA) surgery and to determine whether thoracic or thoracoabdominal aortic aneurysm repair after prior infrarenal AAA surgery is associated with higher mortality and morbidity rates.MethodsMEDLINE, Cochrane Library CENTRAL, and EMBASE databases were searched for relevant articles. Selected articles were critically appraised and meta-analyses were performed.ResultsA total of 12.4% of patients with thoracic aortic aneurysms and 18.7% of patients with thoracoabdominal aortic aneurysms have had prior AAA surgery. The chance of developing a thoracic aortic aneurysm in patients with AAA is 2.2% and 2.5% for developing a thoracoabdominal aortic aneurysm. The mean time interval between prior AAA surgery and subsequent thoracoabdominal aortic aneurysm surgery or detection is 8.0 years with a wide variation between individuals. Surgery in these patients is technically feasible. The 30-day mortality of patients undergoing open thoracoabdominal aortic aneurysm repair does not significantly differ from patients without prior AAA surgery and the 30-day mortality is 11.8%. No data were available about mortality of patients with prior AAA repair undergoing thoracic aortic aneurysm surgery. Morbidity risks are higher in patients with thoracic or thoracoabdominal aortic aneurysms. Prior AAA repair was a significant risk factor for neurological deficit after thoracic or thoracoabdominal aortic aneurysms surgery with relative risks (RRs) of 11.1 (95% confidence interval [CI] 3.8-32.3, P value < .0001) and 2.90 (95% CI 1.26-6.65, P value = .008), respectively. Prior AAA repair was a significant risk factor for developing renal failure in patients undergoing thoracoabdominal aortic aneurysm repair (RR 3.47, 95% CI 1.74-6.91, P value = .0001). Determinants of the prognosis in these patients include distal aortic perfusion, distal extent of the landing zone of the graft, drainage of cerebrospinal fluid for thoracic aortic aneurysm repair and age, history of cardiac diseases, extent of the aneurysm, rupture, amount of estimated blood loss, aortic clamp time, and visceral ischemic times for thoracoabdominal aortic aneurysm repair.ConclusionsA considerable group of patients with thoracic or thoracoabdominal aortic aneurysms have had prior AAA repair. The risk of postoperative morbidity is increased in these patients. Mortality appears to be similar for patients with thoracoabdominal aortic aneurysms. Patients with prior AAA repair undergoing thoracic or thoracoabdominal aortic aneurysm repair should be provided maximum care to protect their spinal cord and renal function

Ultra-stable implanted 83Rb/83mKr electron sources for the energy scale monitoring in the KATRIN experiment

The KATRIN experiment aims at the direct model-independent determination of the average electron neutrino mass via the measurement of the endpoint region of the tritium beta decay spectrum. The electron spectrometer of the MAC-E filter type is used, requiring very high stability of the electric filtering potential. This work proves the feasibility of implanted 83Rb/83mKr calibration electron sources which will be utilised in the additional monitor spectrometer sharing the high voltage with the main spectrometer of KATRIN. The source employs conversion electrons of 83mKr which is continuously generated by 83Rb. The K-32 conversion line (kinetic energy of 17.8 keV, natural line width of 2.7 eV) is shown to fulfill the KATRIN requirement of the relative energy stability of +/-1.6 ppm/month. The sources will serve as a standard tool for continuous monitoring of KATRIN's energy scale stability with sub-ppm precision. They may also be used in other applications where the precise conversion lines can be separated from the low energy spectrum caused by the electron inelastic scattering in the substrate.Comment: 30 pages, 10 figures, 1 table, minor revision of the preprint, accepted by JINST on 5.2.201