A Closed-Form, Consistent and Robust Solution to Uncalibrated Photometric Stereo Via Local Diffuse Reflectance Maxima

Images of an object under different illumination are known to provide strong cues about the object surface. A mathematical formalization of how to recover the normal map of such a surface leads to the so-called uncalibrated photometric stereo problem. In the simplest instance, this problem can be reduced to the task of identifying only three parameters: the so-called generalized bas-relief (GBR) ambiguity. The challenge is to find additional general assumptions about the object, that identify these parameters uniquely. Current approaches are not consistent, i.e., they provide different solutions when run multiple times on the same data. To address this limitation, we propose exploiting local diffuse reflectance (LDR) maxima, i.e., points in the scene where the normal vector is parallel to the illumination direction (see Fig. 1). We demonstrate several noteworthy properties of these maxima: a closed-form solution, computational efficiency and GBR consistency. An LDR maximum yields a simple closed-form solution corresponding to a semi-circle in the GBR parameters space (see Fig. 2); because as few as two diffuse maxima in different images identify a unique solution, the identification of the GBR parameters can be achieved very efficiently; finally, the algorithm is consistent as it always returns the same solution given the same data. Our algorithm is also remarkably robust: It can obtain an accurate estimate of the GBR parameters even with extremely high levels of outliers in the detected maxima (up to 80 % of the observations). The method is validated on real data and achieves state-of-the-art results.

A robust reference signal generator for synchronized ventricular assist devices

Ventricular assist devices (VADs) are blood pumps that offer an option to support the circulation of patients with severe heart failure. Since a failing heart has a remaining pump function, its interaction with the VAD influences the hemodynamics. Ideally, the heart's action is taken into account for actuating the device such that the device is synchronized to the natural cardiac cycle. To realize this in practice, a reliable real-time algorithm for the automatic synchronization of the VAD to the heart rate is required. This paper defines the tasks such an algorithm needs to fulfill: the automatic detection of irregular heart beats and the feedback control of the phase shift between the systolic phases of the heart and the assist device. We demonstrate a possible solution to these problems and analyze its performance in two steps. First, the algorithm is tested using the MIT-BIH arrhythmia database. Second, the algorithm is implemented in a controller for a pulsatile and a continuous-flow VAD. These devices are connected to a hybrid mock circulation where three test scenarios are evaluated. The proposed algorithm ensures a reliable synchronization of the VAD to the heart cycle, while being insensitive to irregularities in the heart rate.

Wie robust sind Arbeitsbeziehung und Therapieerfolg ineinander verzahnt? Eine metaanalytische Bestandsaufnahme

Hintergrund: Die therapeutische Arbeitsbeziehung (alliance) ist das meistuntersuchte Prozessmerkmal in der Psychotherapieforschung schlecht hin und zeigt sich als robuster Prädiktor für Therapieerfolg (r = .275). Fragestellung: Welche Einflussfaktoren (wie beispielsweise kognitive Verhaltenstherapie in randomisierten Trials) moderieren den Zusammenhang zwischen Allianz und Erfolg? Methode: Basierend auf über zweihundert in Englisch, deutsch, französisch und italienisch verfassten Primärstudien werden mögliche Moderatoren metaanalytisch untersucht, die den Zusammenhang zwischen Allianz und Therapieerfolg beeinflussen. Resultate: Der aktuelle Stand der APA-Taskforce kann folgendermaßen zusammengefasst werden: (a) Erhebungszeitpunkt der Allianz, (b) Anzahl Patienten pro Therapeut, (b) Forscherinteresse, (c) Therapieerfolg = Abbrüche, (d) Anteil der Nicht-Weißen Bevölkerung und (e) Alkohol und -Substanzmissbrauch als Ausschlusskriterium, beeinflussen den Zusammenhang zwischen Allianz und Erfolg. Folgenden Aspekten moderieren den Zusammenhang zwischen Allianz und Therapieerfolg nicht: (a) Allianz-Messmittel und Erhebungsperspektive (Patient, Therapeut oder Beobachter), (b) Doktorarbeiten, (c) Therapietradition (Kognitive-Behaviorale, Interpersonale, psychodynamische Therapien), (d) randomisiert kontrollierte Trials, (e) manualisierte Therapien, (f ) störungsspezifische Erfolgsmessung, (g) Persönlichkeitsstörungen, (h) nicht-englisch sprachliche Manuskripte. Diskussion: Durch die Moderatoren kann ein beträchtlicher Anteil der Heterogenität erklärt werden. Die Beziehung zwischen Allianz und Therapieerfolg wird durch konzeptuelle biopsychosozialer Faktoren mitbeeinflusst.

Robust estimates of climate-induced hydrological change in a temperate mountainous region

A sustainable water resources management depends on sound information about the impacts of climate change. This information is, however, not easily derived because natural runoff variability interferes with the climate change signal. This study presents a procedure that leads to robust estimates of magnitude and Time Of Emergence (TOE) of climate-induced hydrological change that also account for the natural variability contained in the time series. Firstly, natural variability of 189 mesoscale catchments in Switzerland is sampled for 10 ENSEMBLES scenarios for the control (1984–2005) and two scenario periods (near future: 2025–2046, far future: 2074–2095) applying a bootstrap procedure. Then, the sampling distributions of mean monthly runoff are tested for significant differences with the Wilcoxon-Mann–Whitney test and for effect size with Cliff’s delta d. Finally, the TOE of a climate change induced hydrological change is determined when at least eight out of the ten hydrological projections significantly differ from natural variability. The results show that the TOE occurs in the near future period except for high-elevated catchments in late summer. The significant hydrological projections in the near future correspond, however, to only minor runoff changes. In the far future, hydrological change is statistically significant and runoff changes are substantial. Temperature change is the most important factor determining hydrological change in this mountainous region. Therefore, hydrological change depends strongly on a catchment’s mean elevation. Considering that the hydrological changes are predicted to be robust in the near future highlights the importance of accounting for these changes in water resources planning.

Robust meta-analytic-predictive priors in clinical trials with historical control information.

Historical information is always relevant for clinical trial design. Additionally, if incorporated in the analysis of a new trial, historical data allow to reduce the number of subjects. This decreases costs and trial duration, facilitates recruitment, and may be more ethical. Yet, under prior-data conflict, a too optimistic use of historical data may be inappropriate. We address this challenge by deriving a Bayesian meta-analytic-predictive prior from historical data, which is then combined with the new data. This prospective approach is equivalent to a meta-analytic-combined analysis of historical and new data if parameters are exchangeable across trials. The prospective Bayesian version requires a good approximation of the meta-analytic-predictive prior, which is not available analytically. We propose two- or three-component mixtures of standard priors, which allow for good approximations and, for the one-parameter exponential family, straightforward posterior calculations. Moreover, since one of the mixture components is usually vague, mixture priors will often be heavy-tailed and therefore robust. Further robustness and a more rapid reaction to prior-data conflicts can be achieved by adding an extra weakly-informative mixture component. Use of historical prior information is particularly attractive for adaptive trials, as the randomization ratio can then be changed in case of prior-data conflict. Both frequentist operating characteristics and posterior summaries for various data scenarios show that these designs have desirable properties. We illustrate the methodology for a phase II proof-of-concept trial with historical controls from four studies. Robust meta-analytic-predictive priors alleviate prior-data conflicts ' they should encourage better and more frequent use of historical data in clinical trials.

Bacillus Calmette-Guérin strain differences have an impact on clinical outcome in bladder cancer immunotherapy

BACKGROUND Whether the commonly used bacillus Calmette-Guérin (BCG) strains Connaught and Tice confer different treatment responses in non-muscle-invasive bladder cancer (NMIBC) is unknown. OBJECTIVES To compare clinical efficacy, immunogenicity, and genetics of BCG Connaught and Tice. DESIGN, SETTING, AND PARTICIPANTS A prospective randomized single-institution trial with treatment of 142 high-risk NMIBC patients with BCG Connaught or Tice. INTERVENTION Patients were randomized to receive six instillations of BCG Connaught or Tice. For experimental studies, BCG strains were compared in C57Bl/6 mice. Bladders and lymphoid tissues were analyzed by cytometry and the latter cultivated to detect live BCG. BCG genomic DNA was sequenced and compared with reference genomes. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Recurrence-free survival was the primary end point of the clinical study. The Kaplan-Meier estimator was used for estimating survival and time-to-event end points. Nonparametric tests served for the analysis of the in vivo results. RESULTS AND LIMITATIONS Treatment with BCG Connaught conferred significantly greater 5-yr recurrence-free survival compared with treatment with BCG Tice (p=0.0108). Comparable numbers of patients experienced BCG therapy-related side effects in each treatment group (p=0.09). In mice, BCG Connaught induced stronger T-helper cell 1-biased responses, greater priming of BCG-specific CD8(+) T cells, and more robust T-cell recruitment to the bladder than BCG Tice. Genome sequencing of the BCG strains revealed candidate genes potentially involved in the differential clinical responses. CONCLUSIONS BCG strain may have an impact on treatment outcome in NMIBC immunotherapy. PATIENT SUMMARY We compared the efficacy of two commonly used bacillus Calmette-Guérin (BCG) strains for the treatment of NMIBC and found that treatment with BCG Connaught prevented recurrences more efficiently than BCG Tice. Comparison of the immunogenicity of the two strains in mice indicated superior immunogenicity of BCG Connaught. We also identified genetic differences that may explain the differential efficacy of the Connaught and Tice BCG strains. TRIAL REGISTRATION NCT00003779.

Etomidate - a review of robust evidence for its use in various clinical scenarios

Etomidate is an intravenous hypnotic with a favourable clinical profile in haemodynamic high-risk scenarios. Currently, there is an active debate about the clinical significance of the drug's side effects and its overall risk-benefit ratio. Etomidate-induced transient adrenocortical suppression is well documented and has been associated with increased mortality in sepsis. In surgical patients at risk of hypotensive complications, however, a review of current literature provides no robust evidence to contraindicate a single-bolus etomidate induction. Large randomised controlled trials as well as additional observational data are required to compare safety of etomidate and its alternatives.

Efficient and Robust Host–Guest Antenna Composite for Light Harvesting

We report discovery of a new efficient and robust antenna composite for light harvesting. The organic dye hostasol red (HR) is strongly luminescent in aprotic solvents but only weakly luminescent in potassium zeolite L (ZL) at ambient conditions. We observed a dramatic increase of the luminescence quantum yield of HR–ZL composites if some or all exchangeable potassium cations of ZL are substituted by an organic imidazolium cation (IMZ+) and if the acceptor HR is embedded in the middle part of the channels, so that it is fully protected by the environment of the perylene dye tb-DXP. This led to the discovery of a highly efficient donor,acceptor-ZL antenna material where tb-DXP acts as donor and HR acts as acceptor. The material has a donor-to-acceptor (D/A) absorption ratio of more than 100:1 and a nearly quantitative FRET efficiency. Synthesis of this host–guest material is reported. We describe a successful procedure for achieving full sealing of the ZL channel entrances such that the guests cannot escape. This new material is of great interest for applications in luminescent solar concentrator (LSC) devices because the efficiency killing self-absorption is very low.

A logarithmic efficient estimator of the probability of ruin with recuperation for spectrally negative Lévy risk processes

This article provides an importance sampling algorithm for computing the probability of ruin with recuperation of a spectrally negative Lévy risk process with light-tailed downwards jumps. Ruin with recuperation corresponds to the following double passage event: for some t∈(0,∞)t∈(0,∞), the risk process starting at level x∈[0,∞)x∈[0,∞) falls below the null level during the period [0,t][0,t] and returns above the null level at the end of the period tt. The proposed Monte Carlo estimator is logarithmic efficient, as t,x→∞t,x→∞, when y=t/xy=t/x is constant and below a certain bound.

Robust indoor localization of narrowband signals

Many location-based services target users in indoor environments. Similar to the case of dense urban areas where many obstacles exist, indoor localization techniques suffer from outlying measurements caused by severe multipath propaga??tion and non-line-of-sight (NLOS) reception. Obstructions in the signal path caused by static or mobile objects downgrade localization accuracy. We use robust multipath mitigation techniques to detect and filter out outlying measurements in indoor environments. We validate our approach using a power-based lo??calization system with GSM. We conducted experiments without any prior knowledge of the tracked device's radio settings or the indoor radio environment. We obtained localization errors in the range of 3m even if the sensors had NLOS links to the target device.

Stereological estimation of particle shape and orientation from volume tensors

In the present paper, we describe new robust methods of estimating cell shape and orientation in 3D from sections. The descriptors of 3D cell shape and orientation are based on volume tensors which are used to construct an ellipsoid, the Miles ellipsoid, approximating the average cell shape and orientation in 3D. The estimators of volume tensors are based on observations in several optical planes through sampled cells. This type of geometric sampling design is known as the optical rotator. The statistical behaviour of the estimator of the Miles ellipsoid is studied under a flexible model for 3D cell shape and orientation. In a simulation study, the lengths of the axes of the Miles ellipsoid can be estimated with CVs of about 2% if 100 cells are sampled. Finally, we illustrate the use of the developed methods in an example, involving neurons in the medial prefrontal cortex of rat.

Plant diversity effects on grassland productivity are robust to both nutrient enrichment and drought

Global change drivers are rapidly altering resource availability and biodiversity. While there is consensus that greater biodiversity increases the functioning of ecosystems, the extent to which biodiversity buffers ecosystem productivity in response to changes in resource availability remains unclear. We use data from 16 grassland experiments across North America and Europe that manipulated plant species richness and one of two essential resources—soil nutrients or water—to assess the direction and strength of the interaction between plant diversity and resource alteration on above-ground productivity and net biodiversity, complementarity, and selection effects. Despite strong increases in productivity with nutrient addition and decreases in productivity with drought, we found that resource alterations did not alter biodiversity–ecosystem functioning relationships. Our results suggest that these relationships are largely determined by increases in complementarity effects along plant species richness gradients. Although nutrient addition reduced complementarity effects at high diversity, this appears to be due to high biomass in monocultures under nutrient enrichment. Our results indicate that diversity and the complementarity of species are important regulators of grassland ecosystem productivity, regardless of changes in other drivers of ecosystem function.