julilili42/papers huggingface dataset:
Machine learning time-local generators of open quantum dynamics
2021-04-30

In the study of closed many-body quantum systems one is often interested in\\nthe evolution of a subset of degrees of freedom. On many occasions it is\\npossible to approach the problem by performing an appropriate decomposition\\ninto a bath and a system. In the simplest case the evolution of the reduced\\nstate of the system is governed by a quantum master equation with a\\ntime-independent, i.e. Markovian, generator. Such evolution is typically\\nemerging under the assumption of a weak coupling between the system and an\\ninfinitely large bath. Here, we are interested in understanding to which extent\\na neural network function approximator can predict open quantum dynamics -\\ndescribed by time-local generators - from an underlying unitary dynamics. We\\ninvestigate this question using a class of spin models, which is inspired by\\nrecent experimental setups. We find that indeed time-local generators can be\\nlearned. In certain situations they are even time-independent and allow to\\nextrapolate the dynamics to unseen times. This might be useful for situations\\nin which experiments or numerical simulations do not allow to capture long-time\\ndynamics and for exploring thermalization occurring in closed quantum systems.\\n
Sensitivity of the Cherenkov Telescope Array for probing cosmology and fundamental physics with gamma-ray propagation
2021-04-30

The Cherenkov Telescope Array (CTA), the new-generation ground-based observatory for γ astronomy, provides unique capabilities to address significant open questions in astrophysics, cosmology, and fundamental physics. We study some of the salient areas of γ cosmology that can be explored as part of the Key Science Projects of CTA, through simulated observations of active galactic nuclei (AGN) and of their relativistic jets. Observations of AGN with CTA will enable a measurement of γ absorption on the extragalactic background light with a statistical uncertainty below 15% up to a redshift z=2 and to constrain or detect γ halos up to intergalactic-magnetic-field strengths of at least 0.3 pG . Extragalactic observations with CTA also show promising potential to probe physics beyond the Standard Model. The best limits on Lorentz invariance violation from γ astronomy will be improved by a factor of at least two to three. CTA will also probe the parameter space in which axion-like particles could constitute a significant fraction, if not all, of dark matter. We conclude on the synergies between CTA and other upcoming facilities that will foster the growth of γ cosmology.
Alzheimer’s Disease—Rationales for Potential Treatment with the Thrombin Inhibitor Dabigatran
2021-04-30

Alzheimer’s disease (AD) is caused by neurodegenerative, but also vascular and hemostatic changes in the brain. The oral thrombin inhibitor dabigatran, which has been used for over a decade in preventing thromboembolism and has a well-known pharmacokinetic, safety and antidote profile, can be an option to treat vascular dysfunction in early AD, a condition known as cerebral amyloid angiopathy (CAA). Recent results have revealed that amyloid-β proteins (Aβ), thrombin and fibrin play a crucial role in triggering vascular and parenchymal brain abnormalities in CAA. Dabigatran blocks soluble thrombin, thrombin-mediated formation of fibrin and Aβ-containing fibrin clots. These clots are deposited in brain parenchyma and blood vessels in areas of CAA. Fibrin-Aβ deposition causes microvascular constriction, occlusion and hemorrhage, leading to vascular and blood–brain barrier dysfunction. As a result, blood flow, perfusion and oxygen and nutrient supply are chronically reduced, mainly in hippocampal and neocortical brain areas. Dabigatran has the potential to preserve perfusion and oxygen delivery to the brain, and to prevent parenchymal Aβ-, thrombin- and fibrin-triggered inflammatory and neurodegenerative processes, leading to synapse and neuron death, and cognitive decline. Beneficial effects of dabigatran on CAA and AD have recently been shown in preclinical studies and in retrospective observer studies on patients. Therefore, clinical studies are warranted, in order to possibly expand dabigatran approval for repositioning for AD treatment.
Modern Sedimentation and Authigenic Mineral Formation in the Chew Bahir Basin, Southern Ethiopia: Implications for Interpretation of Late Quaternary Paleoclimate Records
2021-04-30

We present new mineralogical and geochemical data from modern sediments in the Chew Bahir basin and catchment, Ethiopia. Our goal is to better understand the role of modern sedimentary processes in chemical proxy formation in the Chew Bahir paleolake, a newly investigated paleoclimatic archive, to provide environmental context for human evolution and dispersal. Modern sediment outside the currently dry playa lake floor have higher SiO 2 and Al 2 O 3 (50–70 wt.%) content compared to mudflat samples. On average, mudflat sediment samples are enriched in elements such as Mg, Ca, Ce, Nd, and Na, indicating possible enrichment during chemical weathering (e.g., clay formation). Thermodynamic modeling of evaporating water in upstream Lake Chamo is shown to produce an authigenic mineral assemblage of calcite, analcime, and Mg-enriched authigenic illitic clay minerals, consistent with the prevalence of environments of enhanced evaporative concentration in the Chew Bahir basin. A comparison with samples from the sediment cores of Chew Bahir based on whole-rock MgO/Al 2 O 3 , Ba/Sr and authigenic clay mineral δ 18 O values shows the following: modern sediments deposited in the saline mudflats of the Chew Bahir dried out lake bed resemble paleosediments deposited during dry periods, such as during times of the Last Glacial Maximum and Younger Dryas stadial. Sediments from modern detrital upstream sources are more similar to sediments deposited during wetter periods, such as the early Holocene African Humid Period.
Genome-Scale Metabolic Model of Infection with SARS-CoV-2 Mutants Confirms Guanylate Kinase as Robust Potential Antiviral Target
2021-04-30

The current SARS-CoV-2 pandemic is still threatening humankind. Despite first successes in vaccine development and approval, no antiviral treatment is available for COVID-19 patients. The success is further tarnished by the emergence and spreading of mutation variants of SARS-CoV-2, for which some vaccines are not effective anymore. This highlights the urgent need for antiviral therapies even more. This article describes how the Genome-Scale Metabolic Model (GEM) of the host-virus interaction of human alveolar macrophages and SARS-CoV-2 was refined by incorporating the latest information about the virus&amp;rsquo;s structural proteins and the mutant variants B.1.1.7 and B.1.351. We confirmed the initially identified guanylate kinase as a potential antiviral target with this refined model and identified further potential targets from the purine and pyrimidine metabolism. The model was further extended by incorporating the virus&amp;rsquo; lipid requirements. This opened new perspectives for potential antiviral targets in the altered lipid metabolism. Especially the phosphatidylcholine biosynthesis seems to play a pivotal role in viral replication. The guanylate kinase is even a robust target in all investigated mutation variants currently spreading worldwide. These new insights can guide laboratory experiments for the validation of identified potential antiviral targets. Only the combination of vaccines and antiviral therapies will effectively defeat this ongoing pandemic.
Topographic Divergence of Atypical Cortical Asymmetry and Regional Atrophy Patterns in Temporal Lobe Epilepsy: A Worldwide ENIGMA Study
2021-04-30

A bstract Temporal lobe epilepsy (TLE), a common drug-resistant epilepsy in adults, is primarily a limbic network disorder associated with predominant unilateral hippocampal pathology. Structural MRI has provided an in vivo window into whole-brain grey matter pathology in TLE relative to controls, by either mapping (i) atypical inter-hemispheric asymmetry or (ii) regional atrophy. However, similarities and differences of both atypical asymmetry and regional atrophy measures have not been systematically investigated. Here, we addressed this gap using the multi-site ENIGMA-Epilepsy dataset comprising MRI brain morphological measures in 732 TLE patients and 1,418 healthy controls. We compared spatial distributions of grey matter asymmetry and atrophy in TLE, contextualized their topographies relative to spatial gradients in cortical microstructure and functional connectivity, and examined clinical associations using machine learning. We identified a marked divergence in the spatial distribution of atypical inter-hemispheric asymmetry and regional atrophy mapping. The former revealed a temporo-limbic disease signature while the latter showed diffuse and bilateral patterns. Our findings were robust across individual sites and patients. Cortical atrophy was significantly correlated with disease duration and age at seizure onset, while degrees of asymmetry did not show a significant relationship to these clinical variables. Our findings highlight that the mapping of atypical inter-hemispheric asymmetry and regional atrophy tap into two complementary aspects of TLE-related pathology, with the former revealing primary substrates in ipsilateral limbic circuits and the latter capturing bilateral disease effects. These findings refine our notion of the neuropathology of TLE and may inform future discovery and validation of complementary MRI biomarkers in TLE.
PIAAC Cycle 2 assessment framework: Adaptive problem solving
2021-04-30

This chapter defines the concept of adaptive problem solving (APS) in the second cycle of PIAAC. The concept of APS accounts for the fact that we need to be vigilant, adaptive, and willing to modify our plans when interacting with the social, physical, and technological world of the 21st century. In this framework chapter, the cognitive and metacognitive processes that successful people engage into when solving problems and when adapting to changing conditions are described. In this, the PIAAC assessment of APS draws from a large set of information contexts and task dimensions that drive overall APS performance and individual proficiency levels. Several example items, considerations on item scoring and data capturing as well as a thorough discussion of the relation between APS and other competencies provide a comprehensive overview of the APS measurement framework for PIAAC.
Cyanobacterial Biopolymers
2021-04-30

Cyanobacteria are all performing photosynthesis but they are diverse in metabolic capabilities, such as in the production of various biopolymers. This chapter discusses two of them, polyhydroxybutyrate and cyanophycin, their role in cyanobacterial physiology as well as their potential industrial applications.
Language classification, language contact and Andean prehistory: The North
2021-05-01

Abstract The northern half of the Andes—from Venezuela to Northern Peru—has seen dramatic losses of language diversity since the 16th century. Even so, the region's linguistic fabric is complex and multifaceted, and the impression of relatively low levels of diversity vis‐à‐vis Amazonia is to a perhaps considerable extent the result of different post‐conquest trajectories rather than a reflection of pre‐existing differences. As in Amazonia, branches of widespread families—Chibchan, Quechuan, but also far western outliers of Cariban—coexist with more local language families—principally Barbacoan and Chocoan—as well as a multitude of isolates, in particular on the eastern lowland‐facing slopes of the Andes. Recent and ongoing projects of language documentation and description, as well as reconstitution of colonial sources, are contributing to profiling the linguistic diversity more sharply and more securely. Even at the present state of research, it is patent that the patchwork of languages of the Northern Andes, where evidence is available, evinces strong hallmarks of micro‐ and meso‐level language contact, leading to the emergence of distinctive profiles on regional levels that call into question the idea of a reified ‘Andean’ language type. Furthermore, there is a striking signal of spatially structured typological variation throughout the Andes that is in need of explanation and interdisciplinary contextualization. This article surveys the state of the art on language classification and language contact studies for the Northern Andes, and also discusses how they may inform an interdisciplinary prehistory.
Follow-up definitions in clinical orthopaedic research
2021-05-01

Aims The follow-up interval of a study represents an important aspect that is frequently mentioned in the title of the manuscript. Authors arbitrarily define whether the follow-up of their study is short-, mid-, or long-term. There is no clear consensus in that regard and definitions show a large range of variation. It was therefore the aim of this study to systematically identify clinical research published in high-impact orthopaedic journals in the last five years and extract follow-up information to deduce corresponding evidence-based definitions of short-, mid-, and long-term follow-up. Methods A systematic literature search was performed to identify papers published in the six highest ranked orthopaedic journals during the years 2015 to 2019. Follow-up intervals were analyzed. Each article was assigned to a corresponding subspecialty field: sports traumatology, knee arthroplasty and reconstruction, hip-preserving surgery, hip arthroplasty, shoulder and elbow arthroplasty, hand and wrist, foot and ankle, paediatric orthopaedics, orthopaedic trauma, spine, and tumour. Mean follow-up data were tabulated for the corresponding subspecialty fields. Comparison between means was conducted using analysis of variance. Results Of 16,161 published articles, 590 met the inclusion criteria. Of these, 321 were of level IV evidence, 176 level III, 53 level II, and 40 level I. Considering all included articles, a long-term study published in the included high impact journals had a mean follow-up of 151.6 months, a mid-term study of 63.5 months, and a short-term study of 30.0 months. Conclusion The results of this study provide evidence-based definitions for orthopaedic follow-up intervals that should provide a citable standard for the planning of clinical studies. A minimum mean follow-up of a short-term study should be 30 months (2.5 years), while a mid-term study should aim for a mean follow-up of 60 months (five years), and a long-term study should aim for a mean of 150 months (12.5 years). Level of Evidence: Level I. Cite this article: Bone Jt Open 2021;2(5):344–350.
Relativistic stars in 4D Einstein-Gauss-Bonnet gravity
2021-05-01

Abstract In the present paper we investigate the structure of relativistic stars in 4D Einstein-Gauss-Bonnet gravity. The mass-radius relations are obtained for realistic hadronic and for strange quark star equations of state, and for a wide range of the Gauss-Bonnet coupling parameter α. Even though the deviations from general relativity for nonzero values of α can be large enough, they are still comparable with the variations due to different modern realistic equations of state if we restrict ourselves to moderate values of α. That is why the current observations of the neutron star masses and radii alone can not impose stringent constraints on the value of the parameter α. Nevertheless some rough constraints on α can be put. The existence of stable stellar mass black holes imposes √(α) ≲ 2.6 km for α &gt; 0 while the requirement that the maximum neutron star mass should be greater than two solar masses gives √(|α|) ≲ 3.9 km for α &lt; 0. We also present an exact solution describing the structure of relativistic stars with uniform energy density in 4D Einstein-Gauss-Bonnet gravity.
Immigrant adolescents’ perceptions of cultural pluralism climate: Relations to self‐esteem, academic self‐concept, achievement, and discrimination
2021-05-01

A cultural pluralism climate values differences between groups and fosters learning about different cultures. This study investigated the relation between four facets of cultural pluralism climate (learning about multicultural topics, learning about intercultural relations, interest shown by teachers, interest shown by non-immigrant students) and immigrant students' self-esteem, academic self-concept, achievement and perceived discrimination. We furthermore tested whether academic self-concept, self-esteem, and perceived discrimination mediated the relation between the four facets and achievement. Relying on a sample of 700 immigrant students (M<sub>age</sub> = 12.62 years; SD = 1.12; 45.4% female) from 87 Austrian secondary school classes, all effects were estimated at two levels (L1, individual student level; L2, classroom level) in multilevel mediation models. It was shown that learning about multicultural topics and intercultural relations, and interest shown by teachers positively predicted academic self-concept and self-esteem at L1. Learning about intercultural relations negatively predicted discrimination at L1. At L2, learning about intercultural relations positively predicted academic self-concept and negatively predicted perceived discrimination. None of the facets predicted achievement at L1 and L2. However, academic self-concept (positively) and self-esteem (negatively) fully mediated the effect of learning about multicultural topics, learning about intercultural relations, and interest shown by teachers on achievement at L1.
Some elements for a history of the dynamical systems theory
2021-05-01

Writing a history of a scientific theory is always difficult because it requires to focus on some key contributors and to “reconstruct” some supposed influences. In the 1970s, a new way of performing science under the name “chaos” emerged, combining the mathematics from the nonlinear dynamical systems theory and numerical simulations. To provide a direct testimony of how contributors can be influenced by other scientists or works, we here collected some writings about the early times of a few contributors to chaos theory. The purpose is to exhibit the diversity in the paths and to bring some elements—which were never published—illustrating the atmosphere of this period. Some peculiarities of chaos theory are also discussed.
Blocking glutamate mGlu5 receptors with the negative allosteric modulator CTEP improves disease course in SOD1G93A mouse model of amyotrophic lateral sclerosis
2021-05-01

Background and Purpose The pathogenesis of amyotrophic lateral sclerosis (ALS) is not fully clarified, although excessive glutamate (Glu) transmission and the downstream cytotoxic cascades are major mechanisms for motor neuron death. Two metabotropic glutamate receptors (mGlu 1 and mGlu 5 ) are overexpressed in ALS and regulate cellular disease processes. Expression and function of mGlu 5 receptors are altered at early symptomatic stages in the SOD1 G93A mouse model of ALS and knockdown of mGlu5 receptors in SOD1 G93A mice improved disease progression. Experimental Approach We treated male and female SOD1 G93A mice with 2‐chloro‐4‐((2,5‐dimethyl‐1‐(4‐(trifluoromethoxy)phenyl)‐1 H ‐imidazol‐4‐yl)ethynyl)pyridine (CTEP), an orally available mGlu 5 receptor negative allosteric modulator (NAM), using doses of 2 mg·kg −1 per 48 h or 4 mg·kg −1 per 24 h from Day 90, an early symptomatic disease stage. Disease progression was studied by behavioural and histological approaches. Key Results CTEP dose‐dependently ameliorated clinical features in SOD1 G93A mice. The lower dose increased survival and improved motor skills in female mice, with barely positive effects in male mice. Higher doses significantly ameliorated disease symptoms and survival in both males and females, females being more responsive. CTEP also reduced motor neuron death, astrocyte and microglia activation, and abnormal glutamate release in the spinal cord, with equal effects in male and female mice. No differences were also observed in CTEP access to the brain. Conclusion and Implications Our results suggest that mGlu 5 receptors are promising targets for the treatment of ALS and highlight mGlu5 receptor NAMs as effective pharmacological tools with translational potential.
Pretreatment metastatic growth rate determines clinical outcome of advanced melanoma patients treated with anti-PD-1 antibodies: a multicenter cohort study
2021-05-01

Background Checkpoint inhibitors revolutionized the treatment of metastatic melanoma patients. Although tumor burden and lactate dehydrogenase (LDH) are associated with overall survival (OS), the impact of tumor growth kinetics remains elusive and in part contradictory. The aims of this study were to develop a novel simple and rapid method that estimates pretreatment metastatic growth rate (MGR) and to investigate its prognostic impact in melanoma patients treated with antiprogrammed death receptor-1 (PD-1) antibodies. Methods MGR was assessed in three independent cohorts of a total of 337 unselected consecutive metastasized stage IIIB–IV melanoma patients (discovery cohort: n=53, confirmation cohort: n=126, independent multicenter validation cohort: n=158). MGR was computed during the pretreatment period before initiation of therapy with anti-PD-1 antibodies nivolumab or pembrolizumab by measuring the increase of the longest diameter of the largest target lesion. Tumor doubling time served as quality control. Kaplan-Meier analysis and univariable as well as multivariable Cox regression were used to examine the prognostic impact of MGR. Results Pretreatment MGR &gt;3.9 mm/month was associated with impaired OS in the discovery cohort (HR 6.19, 95% CI 2.92 to 13.10, p&lt;0.0001), in the confirmation cohort (HR 3.62, 95% CI 2.19 to 5.98, p&lt;0.0001) and in the independent validation cohort (HR 2.57, 95% CI 1.56 to 4.25, p=0.00023). Prior lines of systemic treatment did not influence the significance of MGR. Importantly, the prognostic impact of MGR was independent of total tumor burden, diameter of the largest metastasis, number of prior lines of systemic treatment, LDH, as well as liver and brain metastasis (discovery and confirmation cohorts: both p&lt;0.0001). Superiority of MGR compared with these variables was confirmed in the independent multicenter validation cohort (HR 2.92, 95% CI 1.62 to 5.26, p=0.00036). Conclusions High pretreatment MGR is an independent strong prognostic biomarker associated with unfavorable survival of melanoma patients receiving anti-PD-1 antibodies. Further investigations are warranted to assess the predictive impact of MGR in distinct systemic therapeutic regimens.
The Status and Value of Replications in Animal Behavior Science
2021-05-01

Replications are widely considered an essential tool to evaluate scientific claims. However, many fields have recently reported that replication rates are low and - when they are conducted - many findings do not successfully replicate. These circumstances have led to widespread debates about the value of replications for research quality, credibility of research findings, and factors contributing to current problems with replicability. This special issue brings together researchers from various areas within the field of animal behavior to offer their perspective on the status and value of replications in animal behavior science.