Early development of gaze following into distant space in juvenile Greylag geese ( Anser anser )

Visual co-orientation with another's gaze direction (gaze following) may provide important information about the location of food, social interactions or predators. Gaze following has been shown in a variety of mammals, but only in few bird species, and has not been tested in precocial birds at all. It has been suggested that gaze following is an anti-predator behaviour, and in Common ravens (Corvus corax) and rooks (C. frugilegus), it emerges shortly after fledging, at a time when young birds leave the predator-safe nest. However, if gaze following is adaptive, the developmental pattern should differ between altricial and precocial birds. Greylag geese (Anser anser) are highly social birds with a precocial development. Goslings move and feed independently within 24h post-hatching, and they are highly vulnerable to aerial predators. We therefore predicted that greylag geese are capable of gaze following and that they develop this skill already pre-fledging. We experimentally tested 19 hand-raised greylag goslings for their ability to follow a conspecific's gaze when they were between 10days and 6weeks old. In line with our predictions, first responses were already detectable in 10-day-old goslings. Our results therefore not only demonstrate that greylag geese follow the gaze of conspecifics into distant space, but that they also develop this ability much earlier than altricial bird

Magnetism and d-wave superconductivity on the half-filled square lattice with frustration

The role of frustration and interaction strength on the half-filled Hubbard model is studied on the square lattice with nearest and next-nearest neighbour hoppings t and t' using the Variational Cluster Approximation (VCA). At half-filling, we find two phases with long-range antiferromagnetic (AF) order: the usual Neel phase, stable at small frustration t'/t, and the so-called collinear (or super-antiferromagnet) phase with ordering wave-vector $(\pi,0)$ or $(0,\pi)$, stable for large frustration. These are separated by a phase with no detectable long-range magnetic order. We also find the d-wave superconducting (SC) phase ($d_{x^2-y^2}$), which is favoured by frustration if it is not too large. Intriguingly, there is a broad region of coexistence where both AF and SC order parameters have non-zero values. In addition, the physics of the metal-insulator transition in the normal state is analyzed. The results obtained with the help of the VCA method are compared with the large-U expansion of the Hubbard model and known results for the frustrated J1-J2 Heisenberg model. These results are relevant for pressure studies of undoped parents of the high-temperature superconductors: we predict that an insulator to d-wave SC transition may appear under pressure.Comment: 12 pages, 10 figure

The potential of open-access data for flood estimations: uncovering inundation hotspots in Ho Chi Minh City, Vietnam, through a normalized flood severity index

Hydro-numerical models are increasingly important to determine the adequacy and evaluate the effectiveness of potential flood protection measures. However, a significant obstacle in setting up hydro-numerical and associated flood damage models is the tedious and oftentimes prohibitively costly process of acquiring reliable input data, which particularly applies to coastal megacities in developing countries and emerging economies. To help alleviate this problem, this paper explores the usability and reliability of flood models built on open-access data in regions where highly resolved (geo)data are either unavailable or difficult to access yet where knowledge about elements at risk is crucial for mitigation planning. The example of Ho Chi Minh City, Vietnam, is taken to describe a comprehensive but generic methodology for obtaining, processing and applying the required open-access data. The overarching goal of this study is to produce preliminary flood hazard maps that provide first insights into potential flooding hotspots demanding closer attention in subsequent, more detailed risk analyses. As a key novelty, a normalized flood severity index (INFS), which combines flood depth and duration, is proposed to deliver key information in a preliminary flood hazard assessment. This index serves as an indicator that further narrows down the focus to areas where flood hazard is significant. Our approach is validated by a comparison with more than 300 flood samples locally observed during three heavy-rain events in 2010 and 2012 which correspond to INFS-based inundation hotspots in over 73 % of all cases. These findings corroborate the high potential of open-access data in hydro-numerical modeling and the robustness of the newly introduced flood severity index, which may significantly enhance the interpretation and trustworthiness of risk assessments in the future. The proposed approach and developed indicators are generic and may be replicated and adopted in other coastal megacities around the globe

Aluminum depletion induced by complex co-segregation of carbon and boron in a {\Sigma} 5 [3 1 0] bcc-iron grain boundary

The local variation of grain boundary atomic structure and chemistry caused by segregation of impurities influences the macroscopic properties of poylcrystalline materials. Here, the effect of co-segregation of carbon and boron on the depletion of aluminum at a $\Sigma 5\,(3\,1\,0\,) [0\,0\,1]$ tilt grain boundary in a $\alpha-$Fe-$4~at.~\%$Al bicrystal was studied by combining atomic resolution scanning transmission electron microscopy, atom probe tomography and density functional theory calculations. The atomic grain boundary structural units mostly resemble kite-type motifs and the structure appears disrupted by atomic scale defects. Atom probe tomography reveals that carbon and boron impurities are co-segregating to the grain boundary reaching levels of >1.5 at.\%, whereas aluminum is locally depleted by approx. 2~at.\%. First-principles calculations indicate that carbon and boron exhibit the strongest segregation tendency and their repulsive interaction with aluminum promotes its depletion from the grain boundary. It is also predicted that substitutional segregation of boron atoms may contribute to local distortions of the kite-type structural units. These results suggest that the co-segregation and interaction of interstitial impurities with substitutional solutes strongly influences grain boundary composition and with this the properties of the interface.Comment: 26 pages, 10 Figures, 1 Tabl

Küstenstädte unter Wasser : Rückblick, Vorschau und Vorbereitung auf Extremereignisse im Klimawandel

Überschwemmungen sind für küstennahe Städte eine große Herausforderung. Wissenschaftler*innen vom Ludwig-Franzius-Institut erklären beispielhaft, wie die Risiken von Hochwasser in Ho-Chi-Minh-Stadt in Vietnam und der Pauliner Marsch in Bremen eingeschätzt, bewertet und in einem weiteren Schritt eingedämmt werden können

Interstitial Segregation has the Potential to Mitigate Liquid Metal Embrittlement in Iron

The embrittlement of metallic alloys by liquid metals leads to catastrophic material failure and severely impacts their structural integrity. The weakening of grain boundaries by the ingress of liquid metal and preceding segregation in the solid are thought to promote early fracture. However, the potential of balancing between the segregation of cohesion-enhancing interstitial solutes and embrittling elements inducing grain boundary decohesion is not understood. Here, we unveil the mechanisms of how boron segregation mitigates the detrimental effects of the prime embrittler, zinc, in a $\Sigma 5\,[0\,0\,1]$ tilt grain boundary in $\alpha-$Fe ($4~at.\%$ Al). Zinc forms nanoscale segregation patterns inducing structurally and compositionally complex grain boundary states. Ab-initio simulations reveal that boron hinders zinc segregation and compensates for the zinc induced loss in grain boundary cohesion. Our work sheds new light on how interstitial solutes intimately modify grain boundaries, thereby opening pathways to use them as dopants for preventing disastrous material failure.Comment: 29 pages, 6 figures in the main text and 10 figures in the supplementar

Signal-to-noise measurements utilizing a novel dual-energy multimedia detector

Dual-energy measurements are presented utilizing a novel slot-scan digital radiographic imaging detector, operating on gaseous solid state ionization principles. The novel multimedia detector has two basic functional components: a noble gas-filled detector volume operating on gas microstrip principles, and a solid state detector volume. The purpose of this study is to investigate the potential use of this multimedia detector for enhanced dual-energy imaging. The experimental results indicate that the multimedia detector exhibits a large subtracted signal-to-noise ratio. Although the intrinsic merit of this device is being explored for medical imaging, potential applications of the multimedia detector technology in other industrial areas, such as aerospace imaging, aviation security, and surveillance, are also very promising

Effective Adaptation Options to Alleviate Nuisance Flooding in Coastal Megacities—Learning From Ho Chi Minh City, Vietnam

The economies and livelihoods of many coastal megacities are at serious risk from flooding, despite investments in flood defenses. For instance, in Ho Chi Minh City, the construction of a large-scale ring-dike has mitigated negative effects from storm surges, yet damage is still frequently caused by high-intensity rainfalls leading to nuisance flooding, which is responsible for the highest proportion of flood losses in the city today. Because sustainable flood risk management requires detailed spatial information, we analyze the local risk and its components based on a chain of novel models previously calibrated and validated for Ho Chi Minh City. Furthermore, we assess the effectiveness of two decentralized adaptation options, namely private precautionary measures and rainwater retention, for mitigating pluvial flooding. Our integrated risk assessment reveals that the approaches are complementary, which is a major advantage for their implementation. Implementation of both approaches has the potential to reduce the expected annual damage and the number of annually affected households by 16% and 56%, respectively. This is also reflected in a significant reduction of annual losses per household, which we propose as an additional, people-centered indicator of flood risk. Moreover, these measures are well-suited to strengthen citizen participation in risk reduction beyond top-down protection schemes. Complementing the ring-dike with decentralized adaptation options can therefore be seen as an effective and generic strategy to alleviate the impacts of nuisance flooding in coastal megacities, such as Ho Chi Minh City, and should be incentivized by decision-makers. Aside from hydrological and metocean site conditions, both the methodology and findings of this study are transferrable to any coastal megacity facing similar challenges

HSV-1 and Cellular miRNAs in CSF-Derived Exosomes as Diagnostically Relevant Biomarkers for Neuroinflammation

Virus-associated chronic inflammation may contribute to autoimmunity in a number of diseases. In the brain, autoimmune encephalitis appears related to fluctuating reactivation states of neurotropic viruses. In addition, viral miRNAs and proteins can be transmitted via exosomes, which constitute novel but highly relevant mediators of cellular communication. The current study questioned the role of HSV-1-encoded and host-derived miRNAs in cerebrospinal fluid (CSF)-derived exosomes, enriched from stress-induced neuroinflammatory diseases, mainly subarachnoid hemorrhage (SAH), psychiatric disorders (AF and SZ), and various other neuroinflammatory diseases. The results were compared with CSF exosomes from control donors devoid of any neuroinflammatory pathology. Serology proved positive, but variable immunity against herpesviruses in the majority of patients, except controls. Selective ultrastructural examinations identified distinct, herpesvirus-like particles in CSF-derived lymphocytes and monocytes. The likely release of extracellular vesicles and exosomes was most frequently observed from CSF monocytes. The exosomes released were structurally similar to highly purified stem-cell-derived exosomes. Exosomal RNA was quantified for HSV-1-derived miR-H2-3p, miR-H3-3p, miR-H4-3p, miR-H4-5p, miR-H6-3p, miR-H27 and host-derived miR-21-5p, miR-146a-5p, miR-155-5p, and miR-138-5p and correlated with the oxidative stress chemokine IL-8 and the axonal damage marker neurofilament light chain (NfL). Replication-associated miR-H27 correlated with neuronal damage marker NfL, and cell-derived miR-155-5p correlated with oxidative stress marker IL-8. Elevated miR-138-5p targeting HSV-1 latency-associated ICP0 inversely correlated with lower HSV-1 antibodies in CSF. In summary, miR-H27 and miR-155-5p may constitute neuroinflammatory markers for delineating frequent and fluctuating HSV-1 replication and NfL-related axonal damage in addition to the oxidative stress cytokine IL-8 in the brain. Tentatively, HSV-1 remains a relevant pathogen conditioning autoimmune processes and a psychiatric clinical phenotype.</p

Metabolic biomarker signature to differentiate pancreatic ductal adenocarcinoma from chronic pancreatitis

Objective Current non-invasive diagnostic tests can distinguish between pancreatic cancer (pancreatic ductal adenocarcinoma (PDAC)) and chronic pancreatitis (CP) in only about two thirds of patients. We have searched for blood-derived metabolite biomarkers for this diagnostic purpose. Design For a case-control study in three tertiary referral centres, 914 subjects were prospectively recruited with PDAC (n=271), CP (n=282), liver cirrhosis (n=100) or healthy as well as non-pancreatic disease controls (n=261) in three consecutive studies. Metabolomic profiles of plasma and serum samples were generated from 477 metabolites identified by gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry. Results A biomarker signature (nine metabolites and additionally CA19-9) was identified for the differential diagnosis between PDAC and CP. The biomarker signature distinguished PDAC from CP in the training set with an area under the curve (AUC) of 0.96 (95% CI 0.93-0.98). The biomarker signature cut-off of 0.384 at 85% fixed specificity showed a sensitivity of 94.9% (95% CI 87.0%-97.0%). In the test set, an AUC of 0.94 (95% CI 0.91-0.97) and, using the same cut-off, a sensitivity of 89.9% (95% CI 81.0%-95.5%) and a specificity of 91.3% (95% CI 82.8%-96.4%) were achieved, successfully validating the biomarker signature. Conclusions In patients with CP with an increased risk for pancreatic cancer (cumulative incidence 1.95%), the performance of this biomarker signature results in a negative predictive value of 99.9% (95% CI 99.7%-99.9%) (training set) and 99.8% (95% CI 99.6%-99.9%) (test set). In one third of our patients, the clinical use of this biomarker signature would have improved diagnosis and treatment stratification in comparison to CA19-9