Josephson Effect in Pb/I/NbSe2 Scanning Tunneling Microscope Junctions

We have developed a method for the reproducible fabrication of superconducting scanning tunneling microscope (STM) tips. We use these tips to form superconductor/insulator/superconductor tunnel junctions with the STM tip as one of the electrodes. We show that such junctions exhibit fluctuation dominated Josephson effects, and describe how the Josephson product IcRn can be inferred from the junctions' tunneling characteristics in this regime. This is first demonstrated for tunneling into Pb films, and then applied in studies of single crystals of NbSe2. We find that in NbSe2, IcRn is lower than expected, which could be attributed to the interplay between superconductivity and the coexisting charge density wave in this material.Comment: 3 pages, 2 figures. Presented at the New3SC-4 meeting, San Diego, Jan. 16-21 200

Observation of Modulated Quadrupolar Structures in PrPb3

Neutron diffraction measurements have been performed on the cubic compound PrPb3 in a [001] magnetic field to examine the quadrupolar ordering. Antiferromagnetic components with q=(1/2+-d 1/2 0), (1/2 1/2+-d 0) (d~1/8) are observed below the transition temperature TQ (0.4 K at H=0) whose amplitudes vary linear with H and vanish at zero field, providing the first evidence for a modulated quadrupolar phase. For H<1 T, a non-square modulated state persists even below 100 mK suggesting quadrupole moments associated with a Gamma3 doublet ground state to be partially quenched by hybridization with conduction electrons.Comment: Physical Review Letters, in press. 4 pages, 4 figure

Evidence for prevention and screening: recommendations in adults.

A growing body of evidence supports preventive interventions in asymptomatic adults. Primary prevention, which includes counselling (in particular for smoking cessation) and review of immunisation status, has been shown to be more cost-effective than secondary prevention. Evidence supports screening for hypertension, hyperlipidaemia, cervical cancer, colorectal cancer, breast cancer and obesity. Screening for lung, pancreatic and ovarian cancer has no effect on outcome and should not be performed. Controversial preventive interventions include general screening for diabetes mellitus, thyroid disorders and prostate cancer. Physicians should be aware of a possible hidden agenda in patients presenting for a checkup

Low temperature specific heat of the heavy fermion superconductor PrOs4_4Sb12_{12}

We report the magnetic field dependence of the low temperature specific heat of single crystals of the first Pr-based heavy fermion superconductor PrOs$_4$Sb$_{12}$. The low temperature specific heat and the magnetic phase diagram inferred from specific heat, resistivity and magnetisation provide compelling evidence of a doublet ground state and hence superconductivity mediated by quadrupolar fluctuations. This establishes PrOs$_4$Sb$_{12}$ as a very strong contender of superconductive pairing that is neither electron-phonon nor magnetically mediated.Comment: 4 pages, 4 figure

Antiferro-quadrupole state of orbital-degenerate Kondo lattice model with f^2 configuration

To clarify a key role of $f$ orbitals in the emergence of antiferro-quadrupole structure in PrPb$_{3}$, we investigate the ground-state property of an orbital-degenerate Kondo lattice model by numerical diagonalization techniques. In PrPb$_{3}$, Pr$^{3+}$ has a $4f^{2}$ configuration and the crystalline-electric-field ground state is a non-Kramers doublet $\Gamma_{3}$. In a $j$-$j$ coupling scheme, the $\Gamma_{3}$ state is described by two local singlets, each of which consists of two $f$ electrons with one in $\Gamma_{7}$ and another in $\Gamma_{8}$ orbitals. Since in a cubic structure, $\Gamma_{7}$ has localized nature, while $\Gamma_{8}$ orbitals are rather itinerant, we propose the orbital-degenerate Kondo lattice model for an effective Hamiltonian of PrPb$_{3}$. We show that an antiferro-orbital state is favored by the so-called double-exchange mechanism which is characteristic of multi-orbital systems.Comment: 3 pages, 3 figures, Proceedings of Skutterudite2007 (September 26-30, 2007, Kobe

Totgeburt und plötzlicher Kindstod : Gemeinsamkeiten und Differenzen

Die Totgeburtenrate hat in entwickelten Ländern in den letzten 30 Jahren im Gegensatz zur neonatalen Sterblichkeit und der Häufigkeit des plötzlichen Kindstodes kaum abgenommen. Dies ist verwunderlich, da heute weit weniger Totgeburten aufgrund einer Plazentainsuffizienz, eines maternalen Diabetes mellitus, einer Präeklampsie, oder durch Rhesusinkompatibilität und fetale Aneuploidien auftreten. Dagegen steigt die Rate an ätiologisch ungeklärten Fällen von Totgeburten an. Die eindrücklichen Erfolge in der Prävention des plötzlichen Kindstods zeigen, dass auch ätiologisch ungeklärte Erkrankungen wirkungsvoll verhindert werden können. Rauchen und Adipositas, sowie übermäßige Gewichtszunahme als Risikofaktoren für den intrauterinen Fruchttod sind vor Eintritt der Schwangerschaft modifizierbar. Die Erkennung und Therapie von Diabetes mellitus, Gestationsdiabetes und arterieller Hypertonie sind effektive Maßnahmen in der Schwangerschaft zur Verringerung von Totgeburten. Die Geburtseinleitung am Termin wäre ebenfalls eine effektive Methode zur Vermeidung von Totgeburten, wobei für eine vermiedene Totgeburt etwa 300 Geburtseinleitungen mit den damit verbundenen Nachteilen notwendig wären. Abstract During the last 30 years the rate of stillbirths in industrial countries has remained nearly identical, while neonatal mortality und the incidence of the sudden infant death syndrome (SIDS) has declined significantly. This observation is in contrast to the decline of stillbirths due to placental insufficiency, maternal diabetes mellitus, preeclampsia, rhesus incompatibility and fetal aneuploidy. However, the incidence of unexplained stillbirths has increased. The decrease of the incidence of the sudden infant death syndrome proves that prevention of diseases of unknown origin is possible. Smoking, obesity and an excessive increase in body weight before pregnancy are modifiable risk factors for intrauterine stillbirth. The detection and treatment of diabetes mellitus, gestational diabetes and arterial hypertension are effective measures in pregnancy to reduce the risk for stillbirth. The induction of labor at term is also effective in the reduction of stillbirths, however, the burden of elective induction with all of the possible negative effects has to be balanced against the benefit of avoiding intrauterine deaths as approximately 300 labor inductions with the corresponding disadvantages, would be necessary to avoid 1 stillbirth

Non-Fermi Liquid Behavior in Dilute Quadrupolar System Prx_{x}La1−x_{1-x}Pb3_3 with xx≤\le0.05

We have studied the low-temperature properties of Pr$_{x}$La$_{1-x}$Pb$_{3}$ with non-Kramers $\Gamma_{3}$ quadrupolar moments of the crystal-electric-field ground state, for a wide concentration range of Pr ions. For $x$$\le$0.05, the specific heat $C/T$ increases monotonically below $T$=1.5 K, which can be scaled with a characteristic temperature $T^{*}$ defined at each concentration $x$. The electrical resistivity $\rho$$(T)$ in the corresponding temperature region shows a marked decrease deviating from a Fermi-liquid behavior $\rho$$(T)$$\propto$$T^{2}$. The Kondo effect arising from the correlation between the dilute $\Gamma_{3}$ moments and the conduction electrons may give rise to such anomalous behavior

SO(10) Cosmic Strings and SU(3) Color Cheshire Charge

Certain cosmic strings that occur in GUT models such as $SO(10)$ can carry a magnetic flux which acts nontrivially on objects carrying $SU(3)_{color}$ quantum numbers. We show that such strings are non-Abelian Alice strings carrying nonlocalizable colored ``Cheshire" charge. We examine claims made in the literature that $SO(10)$ strings can have a long-range, topological Aharonov-Bohm interaction that turns quarks into leptons, and observe that such a process is impossible. We also discuss flux-flux scattering using a multi-sheeted formalism.Comment: 37 Pages, 8 Figures (available upon request) phyzzx, iassns-hep-93-6, itp-sb-93-6

DOTATOC: A powerful new tool for receptor-mediated radionuclide therapy

This study presents the first successful use of a peptidic vector, DOTATOC, labelled with the β-emitting radioisotope yttrium-90, for the treatment of a patient with somatostatin receptor-positive abdominal metastases of a neuroendocrine carcinoma of unknown localization. Tumour response and symptomatic relief were achieved. In addition, the new substance DOTA-TOC was labelled with the diagnostic chemical analogue indium-111 and studied in three patients with histopathologically verified neuroendocrine abdominal tumours for its diagnostic sensitivity and compared with the commercially available OctreoScan. In all patients the kidney-to-tumour uptake ratio (in counts per pixel) was on average 1.9-fold lower with111In-DOTATOC than with OctreoScan. DOTATOC could be a potential new diagnostic and therapeutic agent in the management of neuroendocrine tumour