The Fermi LAT detection of magnetar-like pulsar PSR J1846-0258 at high-energy gamma-rays

We report the detection of the pulsed signal of the radio-quiet magnetar-like pulsar PSR J1846-0258 in the high-energy \gr-ray data of the Fermi Large Area Telescope (Fermi LAT). We produced phase-coherent timing models exploiting RXTE PCA and Swift XRT monitoring data for the post- (magnetar-like) outburst period from 2007 August 28 to 2016 September 4, with independent verification using INTEGRAL ISGRI and Fermi GBM data. Phase-folding barycentric arrival times of selected Fermi LAT events from PSR J1846-0258, resulted in a 4.2 sigma detection (30--100 MeV) of a broad pulse consistent in shape and aligned in phase with the profiles that we measured with Swift XRT (2.5--10 keV), INTEGRAL ISGRI (20--150 keV) and Fermi GBM (20--300 keV). The pulsed flux (30--100 MeV) is (3.91 +/- 0.97)E-9 photons/(cm^2 s MeV). Declining significances of the INTEGRAL ISGRI 20--150 keV pulse profiles suggest fading of the pulsed hard X-ray emission during the post-outburst epochs. We revisited with greatly improved statistics the timing and spectral characteristics of PSR B1509-58 as measured with the Fermi LAT. The broad-band pulsed emission spectra (from 2 keV up to GeV energies) of PSR J1846-0258 and PSR B1509-58 can be accurately described with similarly curved shapes, with maximum luminosities at 3.5 +/- 1.1 MeV (PSR J1846-0258) and 2.23 +/- 0.11 MeV (PSR B1509-58). We discuss possible explanations for observational differences between Fermi LAT detected pulsars that reach maximum luminosities at GeV energies, like the second magnetar-like pulsar PSR J1119-6127, and pulsars with maximum luminosities at MeV energies, which might be due to geometric differences rather than exotic physics in high-B fields.Comment: 13 pages, 8 figures, accepted by MNRAS on 2017 November 3

Vloek, skel en vulgariteit: Hantering van sosiolinguisties aanstootlike leksikale items

Hierdie artikel wil nie dit wat in onlangse jare oor die leksikografiese bewerking van vloek, skel en ordinere vulgariteit in die taal geskryf is, saamvat of ontleed nie,1 maar probeer slegs om 'n paar praktiese gedagtes oor die onderwerp te ontwikke1. Dit ondersoek die foute wat met die bewerking van die lemma {ok en 'n aantal van sy komposita, verwante lemmas, idiome en ander ramifikasies begaan is. 'n Baie opvallende vermyding van die taalwerklikheid word blootgele en bespreek. 'n Ontwerp vir meer realistiese definisies word voorgele en die etikettering verduidelik. Die etikette vloek, skeltaal, neerhalend en dies meer het betrekking op stilistiese funksies en ,behoort as 'n aparte reeks onderskei te weird van die reeks etikette wat sosiolinguistiese status aandui, soos vulger, geselstaal of verhewe, waarmee dit tradisioneel op 'n gegradeerde skaal saamgegroepeer word.Sleutelwoorde: vloek, skel, vulgariteit, taalwerklikheid, realistiese deflnlsies, stilistiese etiketie, sosiolinguistiese etiketie, leksikografi

Far-field scattering microscopy applied to analysis of slow light, power enhancement, and delay times in uniform Bragg waveguide gratings

A novel method is presented for determining the group index, intensity enhancement and delay times for waveguide gratings, based on (Rayleigh) scattering observations. This far-field scattering microscopy (FScM) method is compared with the phase shift method and a method that uses the transmission spectrum to quantify the slow wave properties. We find a minimum group velocity of 0.04c and a maximum intensity enhancement of ~14.5 for a 1000-period grating and a maximum group delay of ~80 ps for a 2000-period grating. Furthermore, we show that the FScM method can be used for both displaying the intensity distribution of the Bloch resonances and for investigating out of plane losses. Finally, an application is discussed for the slow-wave grating as index sensor able to detect a minimum cladding index change of $10^{-8}$, assuming a transmission detection limit of $10^{-4}$

COGNITIVE THERAPY FOR THE TREATMENT OF DEPRESSIVE SYMPTOMS IN PATIENTS WITH HEART FAILURE

Depressive symptoms are common in patients with heart failure (HF) and adversely affect mortality, morbidity, and health-related quality of life. Cognitive therapy (CT) has been proposed as a non-pharmacological treatment for depressive symptoms in patients with HF. However, there is currently little evidence to support use of CT in patients with HF. The purpose of this dissertation was to develop and test a brief, nurse-delivered CT intervention for the treatment of depressive symptoms in patients with HF. Prior to testing the intervention, preliminary work was conducted resulting in four manuscripts: 1) a review of the evidence for CT in treating depressive symptoms in patients with cardiovascular conditions, 2) a description of living with depressive symptoms in patients with HF and strategies that could be used to manage these symptoms, 3) a review of measures of negative thinking and the identification of a measure of negative thinking that can be used in patients with HF, and 4) an evaluation of the psychometric properties of this measure. Based on information from these manuscripts, a randomized, controlled pilot study was conducted to test the effects of a brief CT intervention on outcomes of hospitalized patients with HF who report depressive symptoms. Forty-two hospitalized patients with HF with mild-moderate depressive symptoms were randomized to a brief CT intervention focused on reducing negative thoughts with thought-stopping and affirmations, or to usual care control. Both groups experienced improvements in depressive symptoms, health-related quality of life, and negative thinking at one week and three months. However, the intervention group experienced longer cardiac event-free survival and fewer cardiovascular hospitalizations and emergency department visits at three months when compared to the control group. This dissertation has fulfilled an important gap in the evidence base for depression treatment in patients with HF by demonstrating that a nurse-delivered, brief CT intervention may improve cardiac event-free survival in patients with HF. This brief CT intervention is replicable, practical, can be delivered by acute care nurses, and may improve clinical outcomes in patients with HF. Additional research is needed to determine the effects of the intervention on long-term outcomes in patients with HF

Electronic Transport Spectroscopy of Carbon Nanotubes in a Magnetic Field

We report magnetic field spectroscopy measurements in carbon nanotube quantum dots exhibiting four-fold shell structure in the energy level spectrum. The magnetic field induces a large splitting between the two orbital states of each shell, demonstrating their opposite magnetic moment and determining transitions in the spin and orbital configuration of the quantum dot ground state. We use inelastic cotunneling spectroscopy to accurately resolve the spin and orbital contributions to the magnetic moment. A small coupling is found between orbitals with opposite magnetic moment leading to anticrossing behavior at zero field.Comment: 7 pages, 4 figure

Evolution of SU(4) Transport Regimes in Carbon Nanotube Quantum Dots

We study the evolution of conductance regimes in carbon nanotubes with doubly degenerate orbitals (``shells'') by controlling the contact transparency within the same sample. For sufficiently open contacts, Kondo behavior is observed for 1, 2, and 3 electrons in the topmost shell. As the contacts are opened more, the sample enters the ``mixed valence'' regime, where different charge states are strongly hybridized by electron tunneling. Here, the conductance as a function of gate voltage shows pronounced modulations with a period of four electrons, and all single-electron features are washed away at low temperature. We successfully describe this behavior by a simple formula with no fitting parameters. Finally, we find a surprisingly small energy scale that controls the temperature evolution of conductance and the tunneling density of states in the mixed valence regime.Comment: 4 pages + supplementary info. The second part of the original submission is now split off as a separate paper (0709.1288