The Gassiplex0.7-2 Integrated Front-End Analog Processor for the HMPID and the Dimuon Spectrometer of ALICE

The most recent member of the Gasplex family of ASICs has been designed in a 0.7 µm n-well CMOS process to meet specifications for the ALICE applications: 500 fC linear dynamic range and a peaking time of 1.2 µs. Its internal circuitry is optimized for the readout of gaseous detectors. A dedicated filter compensates the long hyperbolic signal tail produced by the slow drift of the ions and allows the shaper to achieve perfect return to the base line after 5 µs. Measurement of fabricated chips showed a noise performance of 530 e - rms at 0 pF external input capacitance and 1.2 µs peaking-time, with a noise slope of 11.2 e - rms/pF. The gain is 3.6 mv/fC over a linear dynamic range of 560 fC

Positive outcomes: validity, reliability and responsiveness of a novel person-centred outcome measure for people with HIV

Objectives Despite successful treatment, people living with HIV experience persisting and burdensome multidimensional problems. We aimed to assess the validity, reliability and responsiveness of Positive Outcomes, a patient-reported outcome measure for use in clinical practice. Methods In all, 1392 outpatients in five European countries self-completed Positive Outcomes, PAM-13 (patient empowerment), PROQOL-HIV (quality of life) and FRAIL (frailty) at baseline and 12 months. Analysis assessed: (a) validity (structural, convergent and divergent, discriminant); (b) reliability (internal consistency, test-retest); and (c) responsiveness. Results An interpretable four-factor structure was identified: ‘emotional wellbeing’, ‘interpersonal and sexual wellbeing’, ‘socioeconomic wellbeing’ and ‘physical wellbeing’. Moderate to strong convergent validity was found for three subscales of Positive Outcomes and PROQOL (ρ = −0.481 to −0.618, all p < 0.001). Divergent validity was found for total scores with weak ρ (−0.295, p < 0.001). Discriminant validity was confirmed with worse Positive Outcomes score associated with increasing odds of worse FRAIL group (4.81-fold, p < 0.001) and PAM-13 level (2.28-fold, p < 0.001). Internal consistency for total Positive Outcomes and its factors exceeded the conservative α threshold of 0.6. Test-retest reliability was established: those with stable PAM-13 and FRAIL scores also reported median Positive Outcomes change of 0. Improved PROQOL-HIV score baseline to 12 months was associated with improved Positive Outcomes score (r = −0.44, p < 0.001). Conclusions Positive Outcomes face and content validity was previously established, and the remaining validity, reliability and responsiveness properties are now demonstrated. The items within the brief 22-item tool are designed to be actionable by health and social care professionals to facilitate the goal of person-centred care

The GASSIPLEX0.7-2 Integrated Front-End Analog Processor for the HMPID and Muon Tracker of ALICE

The most recent member of the Gasplex family has been designed in a 0.7 µm n-well CMOS process to meet specifications for the ALICE applications: 500 fC linear dynamic range and a peaking time of 1.2 µs. Its internal circuitry is optimized for the readout of gaseous detectors. A dedicated filter compensates the long hyperbolic signal tail produced by the slow motion of the ions and allows the shaper to achieve perfect return to the base line after 5 µs. Measurement of fabricated chips showed a noise performance of 530 e- rms at 0 pF external input capacitance and 1.2 µs peaking-time, with a noise slope of 11.2 e- rms/pF. The gain is 3.6 mv/fC over a linear dynamic range of 560 fC.Summary:The Gasplex is a 16-channel low noise signal processor built in a 1.5 µm technology and specially designed for gaseous detectors. Each channel consists of a Charge Sensitive Amplifier (CSA) followed by a filter, a Semi-Gaussian shaper and a Track/Hold circuit. The peaking time acts as a delay allowing an external trigger to store the information on a capacitor; finally, the 16 channels are multiplexed to one output. The Gassiplex0.7-2 has been developed to fit the ALICE requirements, using the same circuitry principle, in a 0.7&nbsp; µm process. In gaseous detectors, the ion cloud released by the avalanche around the anode wire induces current as long as it drifts in the electric field from the anode to the cathode. The charge close to the anode can be approximated by the relationship q(t) = Q0Aln(1+t/t0) and the current by I(t) = I0B/(1+t/t0), where Q0 is the total ionic charge and A, B and t0 are constants depending on the detector geometry and the electric field.The CSA stage consists of a folded cascode with a feedback capacitor of 1&nbsp;pF and an active feedback resistor of 20&nbsp;M&#87;. This 20&nbsp;&#109;s decay time constant is necessary in order to be sensitive to the largest possible fraction of detector current, which last over several tens of microseconds. A deconvolution filter has been implemented to compensate the long hyperbolic tail resulting from the ion drift and convert the signal of the CSA into a quasi-step function. To perform the deconvolution, the transfer function of the deconvolver G(s) should be the exact inverse of the transfer function of the detector H(s), namely G(s) = H(s)-1.The charge given by the detector is approximated by the sum of three weighted exponentials. Each exponential is modelled by a pole placed in the feedback of a summing amplifier to implement the inverse transformation: G(s) = Vout/Vin = A/(1+&#98;A); for A large G(s) ~ 1/&#98; and &#98;= K1/(1+sT1) + K2/(1+sT2) + K3/(1+sT3). After deconvolution the filter output looks like a step function with one pole given by the Rf.Cf decay time constant of the CSA. It allows the shaper to maintain a stable and precise return to the base line.The Semi-Gaussian shaper has an original feature: the output of the filter go through two different integrating paths which are compared at the inputs of an OTA; it results in a S-G shape and thereby eliminates the usual differentiation capacitor. In this way the different blocks of the analog channel are DC coupled and permit a high counting rate without base line distortion. The Gassiplex0.7-2 provides an individual channel calibration circuit with a precision of ±1It is also possible to switch off the filter for the readout of Silicon detectors at a gain of 2.1&nbsp;mv/fC and a dynamic range of 900&nbsp;fC. With the deconvolution filter in operation, the measured performances figures are the following: at a power consumption of 9&nbsp;mW/ch, we measured the noise as 530&nbsp;e- rms with 0&nbsp;pF input capacitance and a slope of 11.2&nbsp;e- rms/pF. The non-linearity is ±2&nbsp;fC over the 560&nbsp;fC dynamic range at a gain of 3.6&nbsp;mv/fC. The readout can be performed at 10&nbsp;MHz with a capacitive load of 30&nbsp;pF

Linking structural and electronic properties of high-purity self-assembled GaSb/GaAs quantum dots

We present structural, electrical, and theoretical investigations of self-assembled type-II GaSb/GaAs quantum dots (QDs) grown by molecular beam epitaxy. Using cross-sectional scanning tunneling microscopy (X-STM) the morphology of the QDs is determined. The QDs are of high purity (similar to 100% GaSb content) and have most likely the shape of a truncated pyramid. The average heights of the QDs are 4-6 nm with average base lengths between 9 and 14 nm. Samples with a QD layer embedded into a pn-diode structure are studied with deep-level transient spectroscopy (DLTS), yielding a hole localization energy in the QDs of 609 meV. Based on the X-STM results the electronic structure of the QDs is calculated using 8-band k.p theory. The theoretical localization energies are found to be in good agreement with the DLTS results. Our results also allow us to estimate how variations in size and shape of the dots influence the hole localization energy

The structural, electronic and optical properties of GaSb/GaAs nanostructures for charge-based memory

The potential for GaSb nanostructures embedded in GaAs to operate as charge-based memory elements at room temperature is introduced and explored. Cross-sectional scanning-tunnelling microscopy is employed to directly probe and optimize the growth of nanostructures by molecular beam epitaxy. The results of structural analysis are combined with electrical measurements made with deep-level transient spectroscopy, showing excellent agreement with theoretical calculations which model the electronic structure of the nanostructures using 8-band k.p theory. Hole-localization energies exceeding 600 meV in quantum dots and near-100% material contrast between GaSb-rich quantum rings (QRs) and the surrounding GaAs matrix are revealed (no intermixing). Optical measurements confirm the depth of the hole localization, and demonstrate substantially lower inhomogeneous broadening than has previously been reported. Multiple peaks are partially resolved in ensemble photoluminescence of GaSb/GaAs QRs, and are attributed to charge states from discrete numbers of confined holes

Short interims, long impact? A follow-up study on early career teachers' induction

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Gapless and high-resolution diatom oxygen isotope record of sediment short core EN18232-1 from Lake Khamra, SW Yakutia, Siberia, Russia

The dataset includes diatom oxygen isotope data for 39 samples from short core EN18232-1, Lake Khamra, and corresponding key geochemical characteristics of the purified lake sediment samples based on Energy-Dispersive X-ray Spectroscopy (EDS) measurements. For each sample (Sample ID) the corresponding core depth (Depth sed top/bottom) and the calculated mean age (Age) are given. EDS measurements were carried out by a JEOL M-IT500HR analytical scanning electron microscope (SEM) with an integrated EDS-system supplied with a Peltier element cooled SD detector (SDD) at AWI Potsdam. The standardless procedure was used according to Chapligin et al. (2012), including 6 repetitions, acceleration voltage of 20.0 kV, magnification of 300 and a measuring time of 30 seconds. All detectable elements are normalized to 100% weight. Elements are given as oxides with weight percentages (in %) and summed up to the total sum (total %) of each sample. The diatom oxygen isotope data was generated in the ISOLAB Facility at AWI Potsdam with a semi-automated laserfluorination line (Chapligin et al., 2010) in combination with a SERCON HS2022 mass spectrometer. All δ18Odiatom values are given in per mill (‰) vs. Vienna Standard Mean Ocean Water (VSMOW). The dataset includes the mean of measured δ18Odiatom values (Diatom δ18O mean), the standard deviation (Diatom δ18O std dev) and number of replicates (Repl), as well as the calculated contamination (Contamination in %) and the δ18Odiatom corrected for contamination (Diatom δ18O corrected). Details of the contamination correction and isotope analytics are given in Stieg et al. (2023, in prep)