Fractal analysis of resting state functional connectivity of the brain

A variety of resting state neuroimaging data tend to exhibit fractal behavior where its power spectrum follows power-law scaling. Resting state functional connectivity is significantly influenced by fractal behavior which may not directly originate from neuronal population activities of the brain. To describe the fractal behavior, we adopted the fractionally integrated process (FIP) model instead of the fractional Gaussian noise (FGN) since the FIP model covers more general aspects of fractality than the FGN model. We also introduce a novel concept called the nonfractal connectivity which is defined as the correlation of short memory independent of fractal behavior, and compared it with the fractal connectivity which is an asymptotic wavelet correlation. We propose several wavelet-based estimators of fractal connectivity and nonfractal connectivity for a multivariate fractionally integrated noise (mFIN). The performance of these estimators was evaluated through simulation studies and the analyses of resting state functional MRI data of the rat brain.Comment: The 2012 International Joint Conference on Neural Network

Projektbericht "Sozialisationswissen junger Eltern"

Das Konstanzer Projekt 'Die Lebensverhältnisse junger Familien und das Sozialisationswissen der Eltern' wird vom ZUMA betreut. Die Arbeit beschreibt hauptsächlich die methodische Seite des Projekts, das aus verschiedenen Gründen eine Sonderstellung einnimmt: So wurden nicht nur Einzelpersonen pro Haushalt befragt, sondern Familien mit Kleinkindern; es kamen mehrere Erhebungsinstrumente zum Einsatz, so daß sich die Feldarbeit in mehreren Wellen vollzog; unter der Perspektive der 'ökologischen Sozialisationsforschung' mußte in der Hauptsache mit qualitativen Interviewtechniken gearbeitet werden; schließlich mußte das Material bis in die Details transkulturell vergleichbar gemacht werden (Paralleluntersuchungen in USA, Schweden, Großbritannien und Israel). - Design, Erhebungsinstrumente, Stichprobe und Feldarbeit werden beschrieben. (AR

Bioimpedance Body Measures and Serum Lipid Levels in Masculine Depression

BackgroundMajor depressive disorder (MDD) is a main reason for suicide, and serum lipids are involved in both affective disorders and related suicidal behavior. Moreover, masculine depression has been suggested as a subtype of depression with an increased risk for suicide. Here, we studied the relationship between body measures, serum lipids, suicidal thoughts, and masculine depression.MethodsDepressed patients (44% women) were divided by a sex-separated median-split into a group of 81 “patients with masculine depression” (mean age ± standard error: 36.4 ± 1.6 years) and a group of 82 “patients with non-masculine depression” (age 45.7 ± 1.6 years) according to the Male Depression Risk Scale. We compared body measures, serum lipid levels, and past suicidal ideation between these groups and explored differences between these groups and 176 healthy controls (51% women; age 37.2 ± 1.0 years).ResultsPatients with masculine depression did not significantly differ from patients with non-masculine depression in any of the body measures, lipid markers, or suicidal thoughts. Compared to healthy controls, both patient groups showed significantly higher body fat (B[masculine depression] = 0.041 and B[non–masculine depression] = 0.050), lower high-density lipoprotein (HDL) cholesterol (B = –0.045 and –0.044), and a higher risk for suicidal thoughts (B = 3.927 and 2.663) than healthy controls. Suicidal thoughts were significantly associated with lower low-density lipoprotein (LDL)/HDL ratios (B = –0.455) in patients with depression and with higher LDL cholesterol levels (B = 0.020) in healthy controls subjects.LimitationCorrelational study design and focus on in-patients.ConclusionIn the studied cohort, masculine depression was not significantly associated with the analyzed parameters of body measures, serum lipids, or suicidal thoughts in in-patients with depression

Isolierung neutraler, mono- und dikationischer B2P2-Ringe durch Addition eines Diphosphans an eine Bor-Bor-Dreifachbindung

Das NHC-stabilisierte Diborin B2(SIDep)2 (SIDep=1,3-Bis(2,6-diethylphenyl)imidazolin-2-yliden) unterzieht sich bei Raumtemperatur einer P-P-Bindungsaktivierung mit Tetraethyldiphosphan, wobei mittels 1,2-Diphosphinierung über ein Diphosphoryldiboren in hohen Ausbeuten B2P2-Heterocyclen gebildet werden. In Abhängigkeit vom verwendeten Oxidationsmittel und Gegenion kann dieser Heterocyclus zu einem Radikalkation beziehungsweise Dikation oxidiert werden. Beginnend mit dem planaren, neutralen 1,3-Bis(alkyliden)-1,3-diborata-2,4-diphosphoniocyclobutan führt jeder Oxidationsschritt zu einer verminderten B-B-Bindungslänge und dem Verlust der Planarität durch die Kationisierung. Röntgenstrukturanalysen in Kombination mit DFT- und CASSCF/NEVPT2-Rechnungen offenbaren für die NHC-stabilisierten dikationischen B2P2-Ringe geschlossenschalige, schmetterlingsartige Strukturen, wovon die diradikaloiden Isomere mit planarem Ring in energetischer Nähe liegen

Characterization of iLGADs using soft X-rays

Experiments at synchrotron radiation sources and X-ray Free-Electron Lasers in the soft X-ray energy range ($250$eV--$2$keV) stand to benefit from the adaptation of the hybrid silicon detector technology for low energy photons. Inverse Low Gain Avalanche Diode (iLGAD) sensors provide an internal gain, enhancing the signal-to-noise ratio and allowing single photon detection below $1$keV using hybrid detectors. In addition, an optimization of the entrance window of these sensors enhances their quantum efficiency (QE). In this work, the QE and the gain of a batch of different iLGAD diodes with optimized entrance windows were characterized using soft X-rays at the Surface/Interface:Microscopy beamline of the Swiss Light Source synchrotron. Above $250$eV, the QE is larger than $55\%$ for all sensor variations, while the charge collection efficiency is close to $100\%$. The average gain depends on the gain layer design of the iLGADs and increases with photon energy. A fitting procedure is introduced to extract the multiplication factor as a function of the absorption depth of X-ray photons inside the sensors. In particular, the multiplication factors for electron- and hole-triggered avalanches are estimated, corresponding to photon absorption beyond or before the gain layer, respectively.Comment: 16 pages, 8 figure