VIPSCAL: A combined vector ideal point model for preference data

In this paper, we propose a new model that combines the vector model and theideal point model of unfolding. An algorithm is developed, called VIPSCAL, thatminimizes the combined loss both for ordinal and interval transformations. As such,mixed representations including both vectors and ideal points can be obtained butthe algorithm also allows for the unmixed cases, giving either a complete idealpointanalysis or a complete vector analysis. On the basis of previous research,the mixed representations were expected to be nondegenerate. However, degeneratesolutions still occurred as the common belief that distant ideal points can be represented by vectors does not hold true. The occurrence of these distant ideal points was solved by adding certain length and orthogonality restrictions on the configuration. The restrictions can be used both for the mixed and unmixed cases in several ways such that a number of different models can be fitted by VIPSCAL.unfolding;ideal point model;vector model

VIPSCAL: A combined vector ideal point model for preference data

In this paper, we propose a new model that combines the vector model and the ideal point model of unfolding. An algorithm is developed, called VIPSCAL, that minimizes the combined loss both for ordinal and interval transformations. As such, mixed representations including both vectors and ideal points can be obtained but the algorithm also allows for the unmixed cases, giving either a complete ideal pointanalysis or a complete vector analysis. On the basis of previous research, the mixed representations were expected to be nondegenerate. However, degenerate solutions still occurred as the common belief that distant ideal points can be represented by vectors does not hold true. The occurrence of these distant ideal points was solved by adding certain length and orthogonality restrictions on the configuration. The restrictions can be used both for the mixed and unmixed cases in several ways such that a number of different models can be fitted by VIPSCAL

Near-infrared Fourier transform room-temperature photoluminescence of erbium complexes

A modified Fourier transform (FT) Raman bench spectrometer designed for the detection of weak light emission in the 800–1700 nm wavelength region has been used to demonstrate the advantages of FT spectroscopy for measuring near-infrared photoluminescence spectra of lanthanide complexes with a good resolution and very good sensitivity. This apparatus has been tested with an ultraviolet laser source (325 nm) on three standard erbium complexes. The 4I13/24I15/2 emission of tris-(acetylacetonato) (1,10 phenanthroline) erbium [Er(acac)3(phen)], tris-(4,4,4,-trifluoro-1-(2 thenoyl)-1,3-butenedione) (1,10 phenanthroline) erbium [Er(TTFA)3(phen)] and tris(8-hydroxyquinolinato) erbium [Erq3] has thus been recorded in solution and in the solid state and compared with literature. ©2003 American Institute of Physics

PCovR2:A flexible principal covariates regression approach to parsimoniously handle multiple criterion variables

Principal covariates regression (PCovR) allows one to deal with the interpretational and technical problems associated with running ordinary regression using many predictor variables. In PCovR, the predictor variables are reduced to a limited number of components, and simultaneously, criterion variables are regressed on these components. By means of a weighting parameter, users can flexibly choose how much they want to emphasize reconstruction and prediction. However, when datasets contain many criterion variables, PCovR users face new interpretational problems, because many regression weights will be obtained and because some criteria might be unrelated to the predictors. We therefore propose PCovR2, which extends PCovR by also reducing the criteria to a few components. These criterion components are predicted based on the predictor components. The PCovR2 weighting parameter can again be flexibly used to focus on the reconstruction of the predictors and criteria, or on filtering out relevant predictor components and predictable criterion components. We compare PCovR2 to two other approaches, based on partial least squares (PLS) and principal components regression (PCR), that also reduce the criteria and are therefore called PLS2 and PCR2. By means of a simulated example, we show that PCovR2 outperforms PLS2 and PCR2 when one aims to recover all relevant predictor components and predictable criterion components. Moreover, we conduct a simulation study to evaluate how well PCovR2, PLS2 and PCR2 succeed in finding (1) all underlying components and (2) the subset of relevant predictor and predictable criterion components. Finally, we illustrate the use of PCovR2 by means of empirical data

Dye-sensitized Er3+-doped CaF2 nanoparticles for enhanced near-infrared emission at 1.5 μm

Lanthanide (Ln)-doped nanoparticles have shown potential for applications in various fields. However, the weak and narrow absorption bands of the Ln ions (Ln3+), hamper efficient optical pumping and severely limit the emission intensity. Dye sensitization is a promising way to boost the near-infrared (NIR) emission of Er3+, hence promoting possible application in optical amplification at 1.5 μm, a region that is much sought after for telecommunication technology. Herein, we introduce the fluorescein isothiocyanate (FITC) organic dye with large absorption cross section as energy donor of small-sized (∼3.6 nm) Er3+-doped CaF2 nanoparticles. FITC molecules on the surface of CaF2 work as antennas to efficiently absorb light, and provide the indirect sensitization of Er3+ boosting its emission. In this paper, we employ photoluminescence and transient absorption spectroscopy, as well as density functional theory calculations, to provide an in-depth investigation of the FITC → Er3+ energy transfer process. We show that an energy transfer efficiency of over 89% is achieved in CaF2:Er3+@FITC nanoparticles resulting in a 28 times enhancement of the Er3+ NIR emission with respect to bare CaF2:Er3+. Through the multidisciplinary approach used in our work, we are able to show that the reason for such high sensitization efficiency stems from the suitable size and geometry of the FITC dye with a localized transition dipole moment at a short distance from the surface of the nanoparticle

The COVID-19 outbreak increases maternal stress during pregnancy, but not the risk for postpartum depression

The COVID-19 pandemic affects society and may especially have an impact on mental health of vulnerable groups, such as perinatal women. This prospective cohort study of 669 participating women in the Netherlands compared perinatal symptoms of depression and stress during and before the pandemic. After a pilot in 2018, recruitment started on 7 January 2019. Up until 1 March 2020 (before the pandemic), 401 women completed questionnaires during pregnancy, of whom 250 also completed postpartum assessment. During the pandemic, 268 women filled out at least one questionnaire during pregnancy and 59 postpartum (1 March-14 May 2020). Pregnancy-specific stress increased significantly in women during the pandemic. We found no increase in depressive symptoms during pregnancy nor an increase in incidence of high levels of postpartum depressive symptoms during the pandemic. Clinicians should be aware of the potential for increased stress in pregnant women during the pandemic

Long-term anaesthesia of broiler chickens

Objective To provide stable anaesthesia of long duration in broiler chickens in order to perform a terminal caecal ligated loop procedure. Study design Prospective experimental study. Animals Seven clinically healthy broiler chickens (Gallus domesticus) aged 27–36 days, weighing 884–2000 g. Methods Anaesthesia was induced and maintained with isoflurane in oxygen. All birds underwent intermittent positive pressure ventilation for the duration. End-tidal carbon dioxide, peripheral haemoglobin oxygen saturation, heart rate and oesophageal temperature were monitored continuously. All birds received intraosseous fluids. Butorphanol (2 mg kg–1) was administered intramuscularly at 2 hourly intervals. Euthanasia by parenteral pentobarbitone was performed at the end of procedure. Results Stable anaesthesia was maintained in four chickens for durations ranging from 435 to 510 minutes. One bird died and one was euthanized after 130 and 330 minutes, respectively, owing to surgical complications and another died from anaesthetic complication after 285 minutes. Conclusions and clinical relevance Long-term, stable anaesthesia is possible in clinically healthy chickens, provided complications such as hypothermia and hypoventilation are addressed and vital signs are carefully monitored. There are no known previous reports describing monitored, controlled anaesthesia of this duration in chickens