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Structural and chemical insights on the incorporation of americium into zircaloy-derived monoclinic zirconia
No full textMonoclinic zirconia (m-ZrO2) forms on the internal surface of nuclear fuel Zircaloy cladding, acting as a critical barrier against radionuclide release at the fuel-cladding interface. However, the incorporation of minor actinide elements like americium in m-ZrO₂ and resultant structural chemistry remains poorly understood. Using a combination of diffraction and high-resolution X-ray spectroscopic techniques, we have examined m-ZrO2 with 5 mol% Am doping. We show Am enters m-ZrO2 tetravalently, where its solubility is approximately 1.0 mol%, m-(Am4+0.011(7)Zr4+0.989(7))O2, attributed to the large Am4+ cation, where excess Am, that is predominantly trivalent, adopts a C-type (Am4+/3+1-xZr4+x)2O3+x phase in space group Ia-3. The known reversible high temperature phase transformation of m-ZrO2 to tetragonal is further shown to be reduced from 1150 oC to 1050 oC via Am4+ incorporation. The investigation provides critical insight into the chemical reactivity and speciation of minor actinide elements with nuclear fuel cladding related m-ZrO₂
Making Observed and Modeled Martian Dust Storm Trajectories Visible Using a New Automatic Tracking Algorithm
No full textDust in the atmosphere of Mars, along with its radiative effects, is the central factor for understanding the Martian climate. Global circulation models and remote sensing observations are used to shed light on the evolution of Martian dust storms. Trajectories of Martian dust storms have been investigated by manual treatment of Mars daily global maps from the MARs Color Imager. However, the tracking of dust storms has neither been automated, nor systematically compared with modeled dust storm trajectories. We therefore developed a simple algorithm to detect regions with an enhanced atmospheric dust content and to attribute these regions to a trajectory. We applied this algorithm to daily global maps of measurements of the column dust optical depth for Mars Years 24–35, and found 20 dust storm trajectories lasting for at least 10 Sols. We compared these observation-based trajectories with the corresponding model-based trajectories from our own simulations using the global circulation model Mars Planetary Climate Model version 6. The obtained distributions of storm speed and direction of propagation show strong similarities between observations and model, demonstrating a reasonably good performance of the model with regard to dust storm trajectories. We find that most dust storms on Mars are traveling east- or westwards, but that dust storms propagating westwards are less well represented in the model. The developed algorithm can be used as a tool for model evaluation, but also for tracking meteorological conditions along dust storms' trajectories, allowing for further development of dust storm understanding
The isominwidth problem on the 2-sphere
No full textPál’s isominwidth theorem states that for a fixed minimal width, the regular triangle has minimal area. A spherical version of this theorem was proven by Bezdek and Blekherman, if the minimal width is at most /2. If the width is greater than /2, the regular triangle no longer minimizes the area at fixed minimal width. We show that the minimizers are instead given by the polar sets of spherical Reuleaux triangles. Moreover, stability versions of the two spherical inequalities are obtained
Collaborative learning processes – validation of a standardized questionnaire for collaborative learning settings
No full textIm vorliegenden Beitrag wird ein standardisierter Fragebogen zur Erfassung kooperativer Lernprozesse in (Hoch-)Schulen präsentiert, der unter Bezugnahme auf bisherige Erkenntnisse gruppenbezogene Lernprozesse in der Selbsteinschätzung von Lernern multidimensional abbildet. Die Prozesse wurden im Hinblick auf kognitive, metakognitive und sozial-relationale Gruppenaktivitäten erfasst. Nach Pilotierungsstudien wurde der Fragebogen mit insgesamt 30 Items im Rahmen eines kooperativen Lernsettings in Universitätsseminaren eingesetzt. Die durchgeführte kooperative Lernphase wurde von den Studenten ( N = 333 in 114 Gruppen) entlang der genannten Dimensionen bewertet. Darüber hinaus wurden der Lerngewinn und die Zufriedenheit sowie die Fähigkeit zur Perspektivenübernahme in der Selbsteinschätzung erfasst. Die Ergebnisse der faktorenanalytischen Validierung zeigen, dass auf Individualebene zwischen den unterschiedlichen Dimensionen differenziert werden kann; auf Gruppenebene gelingt dies nur mit Einschränkungen. Dass Zusammenhänge mit der Perspektivenübernahme sowie dem Lernzuwachs und der Zufriedenheit aufgezeigt werden können, verweist auf die weitere Konstrukt- und Kriteriumsvalidität. Dennoch müssen bei der Interpretation einige Limitationen berücksichtigt werden.This paper presents a new questionnaire to assess the quality of collaborative learning processes in schools or universities from the learners' perspective. Based on previous research, the questionnaire measures collaborative learning processes along the dimensions of groups' cognitive, metacognitive, and relational activities. The questionnaire was piloted using a sample of secondary school students and was then validated in undergraduate courses ( N = 333 students nested in 114 groups). The quality of the collaborative learning setting was assessed in terms of the aforementioned dimensions. Furthermore, the self-reported learning gains, the satisfaction and the group members' ability for perspective-taking were captured to test construct and criterion validity. Multilevel factor analysis was conducted. At the individual level, the dimensions can be empirically separated, while at the group level some factor correlations are high. In addition, the dimensions are associated with perspective-taking ability, learning gains, and overall satisfaction indicating construct and criterion validity. In conclusion, limitations and practical implications are emphasized
The importin-alpha superfamily engages in ethylene signaling by shuttling ETHYLENE INSENSITIVE 2 from the endoplasmic reticulum to the nucleus
No full textPlant hormones are small molecules that modulate a plethora of growth and developmental pathways. Among these molecules, ethylene is known to modulate several important agronomical traits, including fruit ripening and senescence. However, the mechanisms, pathways, and processes of ethylene signaling from the receptors at the endoplasmic reticulum (ER) membrane to the transcriptional regulators in the nucleus remain to be elucidated. Here, we demonstrate that the importin alpha superfamily of nuclear transport receptors plays a pivotal role by transporting ethylene key regulator ETHYLENE INSENSITIVE 2 (EIN2) from the ER into the nucleus. Our findings show that importin α (impα) single- and triple-mutant seedlings of Arabidopsis thaliana retain a normal ethylene response, as evidenced by the typical triple-response phenotype observed in the presence of ethylene. In vitro and in planta interaction studies demonstrate that EIN2 is recognized as cargo by all nine IMPα isoforms, though with distinct affinities. Specifically, the binding studies reveal that IMPα1/2/3/4/7 are the most relevant isoforms for the nucleocytoplasmic transport of EIN2. Based on computational interaction predictions, we have identified potential binding modes and offer novel mechanistic insights into the interaction between the nuclear localization signal (NLS) motif of EIN2 and the IMPα superfamily. Our results provide novel insights into the mechanism by which the ethylene signal is transmitted from the ER membrane to the nucleus. The data pave the way for a more comprehensive understanding of the ethylene signaling pathway and the central role of EIN2
Parental Health Shocks and Child Outcomes at Ages 17–25: Evidence From Germany
No full textObjective
To investigate the impact of various parental health shocks, including parental death, on young adults' life satisfaction and mental health, personality traits, as well as NEET status (i.e., being neither in employment, education, nor training).
Background
Theoretical considerations and previous cross-sectional studies suggest that parental health problems negatively affect child outcomes and may play an important role in the intergenerational transmission of inequality. Evidence remains limited, however, and several studies have found no or negligible effects when using designs that address unobserved confounding. Prior studies tend to investigate only a small set of parental shocks and child outcomes simultaneously, rarely having follow-up periods beyond adolescence, and disproportionately focus on the Nordic countries.
Method
We use data from the 1991–2021 waves of the nationally representative German Socio-Economic Panel (SOEP) to investigate the impact of a wide range of parental health shocks (extended hospitalization, cancer, stroke, cardiac disease, depression, death). Child outcomes are assessed at ages 17 to 25 and include measures of life satisfaction, mental health, personality (locus of control, Big Five), and NEET status. We implement pooled cross-sectional analyses conditioning on key observables as well as longitudinal individual and family fixed effects regressions to account for unobserved confounding.
Results
Cross-sectional results show that parental health shocks are associated with lower child life satisfaction and mental health, increased NEET risks, as well as higher neuroticism and a more external locus of control, but none of the other personality outcomes. Associations appear to be mostly due to confounding, however, since coefficients are strongly attenuated in longitudinal fixed effects models and only the associations with NEET status remain statistically significant.
Conclusion
Children in Germany appear mostly resilient against serious parental health shocks. Although associations between parental health and child outcomes seem to be largely driven by selection effects, both parental and child health may still play an important role in the intergenerational transmission of inequality, for example, by mediating the effects of shared socio-economic (dis)advantages or genetic predispositions
Analysis of different techniques for injection of the interspinal space in horses
No full textBackground
Impingement of spinous processes (SPs) is commonly diagnosed in the equine athlete. For diagnostic and therapeutic purposes, local injections are performed at the level of the space between adjacent spinous processes in affected horses.
Objectives
To assess the accuracy of different techniques for the local injection of the interspinal space in the equine thoracolumbar spine.
Study Design
Ex vivo experimental study.
Methods
Equine thoracolumbar spine specimens were used to compare three techniques for needle insertion (midline; bilateral abaxial; unilateral oblique), two needles (20G—1½″; 20G—3½″) and two volumes (5 mL; 20 mL) for local injection of the interspinal space. Additionally, needle insertion based on radiographic, ultrasonographic guidance, or palpation was assessed. Computed tomographic analysis and anatomical dissection were performed to evaluate the distribution of the injected volume.
Results
The most accurate injection of the interspinous ligament was achieved when the midline injection method using a 20G—1½″ short needle and a volume of 5 mL was used. Wide distribution of the injected volume was observed when the bilateral abaxial injection technique was utilised. The unilateral oblique injection technique led to significantly asymmetrical unilateral distribution of the injectate. Radiographic guidance did not increase the accuracy of the injection.
Conclusion
The midline injection method is the most reliable technique for the targeted injection of the thoracolumbar interspinal space
Continuous-wave quantum light control via engineered Rydberg-induced dephasing
No full textWe analyze several implementations of all-optical single-photon transistors (SPTs) operating in the continuous-wave (cw) regime, as presented in the companion paper [Phys. Rev. A 113, L011701 (2026)]. The devices rely on ensembles of Rydberg atoms interacting via van der Waals interactions. Under electromagnetically induced transparency (EIT), a weak probe field is fully transmitted through the atomic ensemble in the absence of control photons. Exciting a collective Rydberg state with a single control photon breaks the EIT condition, thereby strongly suppressing the probe transmission. We show how collective Rydberg interactions in an atomic ensemble, confined either in an optical cavity or in free space, give rise to two distinct probe-induced dephasing mechanisms. These processes localize the control excitations, extend their lifetimes, and increase the device efficiency. We characterize the SPTs in terms of control-photon absorption probability and probe gain, supported by numerical simulations of realistic one- and three-dimensional ensembles. The proposed cw devices complement previously demonstrated SPTs and broaden the toolbox of quantum light manipulation circuitry
Advances in Ischemic Stroke: The Role of Imaging Biomarkers in Improving Diagnosis, Prognosis, and Therapeutic Decision-making
No full textIn summary, MRI and CT are excellent diagnostic tools in the acute phase of
stroke, providing valuable information that is crucial for understanding individual
stroke pathology. The discussed studies highlight the potential of various imaging
biomarkers, including thrombus characteristics on CT, FLAIR hyperintense
vessels, vessel size determined on VSI, and underlying small vessel disease, all
of which provide imaging-based physiological information to assess the patientspecific
risk-benefit profile.
There is still a strong need for the definitions of these imaging biomarkers to be
standardized across centers and sites. Only in this way can the true diagnostic and
prognostic value of these biomarkers be tested in a multicenter, controlled setting
and the actual clinical utility be sufficiently assessed. Nonetheless, the multitude
of information gained through different acute imaging modalities can be explored
in smaller cohort studies like ours. These findings contribute to both our
pathophysiological understanding of ischemic stroke and move us towards a more
imaging-based and targeted treatment concept in all-around stroke care
