First-principles search of hot superconductivity in La-X-H ternary hydrides

Motivated by the recent claim of hot superconductivity with critical temperatures up to 550 K in La + x hydrides, we investigate the high-pressure phase diagram of compounds that may have formed in the experiment, using first-principles calculations for evolutionary crystal structure prediction and superconductivity. Starting from the hypothesis that the observed Tc may be realized by successive heating upon a pre-formed LaH10 phase, we examine plausible ternaries of lanthanum, hydrogen and other elements present in the diamond anvil cell: boron, nitrogen, carbon, platinum, gallium, gold. We find that only boron and, to a lesser extent, gallium form metastable superhydride-like structures that can host high-Tc superconductivity, but the predicted Tc’s are incompatible with the experimental reports. Our results indicate that, while the claims of hot superconductivity should be reconsidered, it is very likely that unknown H-rich ternary or multinary phases containing lanthanum, hydrogen, and possibly boron or gallium may have formed under the reported experimental conditions, and that these may exhibit superconducting properties comparable, or even superior, to those of currently known hydrides.

Searching for Gravitationally Lensed Gamma-Ray Bursts with Their Afterglows

Gamma-ray bursts (GRBs) at high redshifts are expected to be gravitationally lensed by objects of different mass scales. Other than a single recent claim, no lensed GRB has been detected so far by using gamma-ray data only. In this paper, we suggest that multiband afterglow data might be an efficient way to search for lensed GRB events. Using the standard afterglow model, we calculate the characteristics of the lensed afterglow lightcurves under the assumption of two popular analytic lens models: the point-mass and singular isothermal sphere models. In particular, when different lensed images cannot be resolved, their signals would be superimposed together with a given time delay. In this case, the X-ray afterglows are likely to contain several X-ray flares of similar width in linear scale and similar spectrum, and the optical afterglow lightcurve will show re-brightening signatures. Since the lightcurves from the image arriving later would be compressed and deformed in the logarithmic timescale, the larger time delay (i.e., the larger mass of the lens), the easier it is to identify the lensing effect. We analyzed the archival data of optical afterglows and found one potential candidate of the lensed GRB (130831A) with time delay ∼500 s; however, observations of this event in gamma-ray and X-ray bands seem not to support the lensing hypothesis. In the future, with the cooperation of the all-sky monitoring gamma-ray detectors and multiband sky survey projects, the method proposed in this paper would be more efficient in searching for strongly lensed GRBs.

Towards great ethno-civilizations and spiritual empires? How the European New Right imagines a post-liberal world order

Far-right parties and pundits are often portrayed as parochial nationalists obsessed with the idea of national sovereignty. Opposed to a liberal world order, they prefer a rogue world of nation-states on the loose. This essay seeks to complicate that narrative. It suggests that alongside political parties with a nationalist agenda, an increasing number of voices on the radical Right are now pushing for a re-spiritualized world order in which cultures, civilizations, and empires are to set the scene. This vision of global order echoes Christopher Coker’s recent claim that “we now live in a world in which civilization is fast becoming the currency of international politics.” But, why does this strand of the far-right prefer civilizations to nation-states? To ponder this question, this essay zooms in on the European New Right and more precisely two of its main luminaries, Alain de Benoist and Aleksandr Dugin. It shows how the New Right stretches back to classical geopolitics to imagine a future polycentric world order in which large civilizations are set free from American hegemony. The empires of the future are no longer underpinned by nation-states but by ethnopluralism—a “blossoming variety” of local, ethnic, agrarian polities.

Improving online and offline gain from repetitive practice using anodal tDCS at dorsal premotor cortex

Administering anodal transcranial direct current stimulation at the left dorsal premotor cortex (PMd) but not right PMd throughout the repetitive practice of three novel motor sequences resulted in improved offline performance usually only observed after interleaved practice. This gain only emerged following overnight sleep. These data are consistent with the proposed proprietary role of left PMd for motor sequence learning and the more recent claim that PMd is central to sleep-related consolidation of novel skill memory.

The Triviality of the New Innovation and Impact in Archaeology and Beyond

What drives archaeology? Is it new empirical discoveries, new methods or new theory? These factors combined are the fuel of the discipline, is the obvious answer. However, debates and research articles frequently reveal how a perceived need for novelty, originality and impact tends to disentangle this triumvirate of archaeological virtues, giving precedence to one asset over others as the supposed driving force. Focusing on archaeological theory, this article taps into current discussions of the nature of archaeological change, reviewing debates on the formation of archaeological theory, its legitimisation and usefulness. Specifically, I address a recent claim that archaeological theory too readily undermines itself by adopting immature ideas and concepts from other disciplines in an uncritical pursuit of novelty. Finally, I discuss how archaeology may contribute more generally to the formation of theory in the humanities by returning so-called borrowed theory.

Cosmic Tangle: Loop Quantum Cosmology and CMB Anomalies

Loop quantum cosmology is a conflicted field in which exuberant claims of observability coexist with serious objections against the conceptual and physical viability of its current formulations. This contribution presents a non-technical case study of the recent claim that loop quantum cosmology might alleviate anomalies in the observations of the cosmic microwave background.

A new resultative construction in Spanish? A reply to Rodríguez Arrizabalaga

We respond to Rodríguez Arrizabalaga’s recent claim that Spanish shows genuine cases of strong resultative constructions, e.g. Juan apuñaló a Tomás hasta la muerte ‘John stabbed Tom to death’, argued to be equivalent to the English construction with the PP to death. This claim is theoretically relevant as it challenges the verb-framed behavior of Spanish with respect to Talmy’s typology. Adopting a constructivist view of argument structure, we argue that Spanish hasta la muerte and English to death constructions of this type involve two completely distinct syntactic configurations, and that only the English to death PP can be regarded as a resultative phrase. We claim that the Spanish hasta PP is syntactically computed as an adjunct external to the argument structure of the predicate and provides a boundary to the predicate it merges with. We thus show that the Spanish construction with hasta la muerte fully conforms to the class of Talmy’s verb-framed languages in that this type of construction is expected to be fully available and productive in this class of languages.

A new resultative construction in Spanish? A reply to Rodríguez Arrizabalaga

We respond to Rodríguez Arrizabalaga’s recent claim that Spanish shows genuine cases of strong resultative constructions, e.g. Juan apuñaló a Tomás hasta la muerte ‘John stabbed Tom to death’, argued to be equivalent to the English construction with the PP to death. This claim is theoretically relevant as it challenges the verb-framed behavior of Spanish with respect to Talmy’s typology. Adopting a constructivist view of argument structure, we argue that Spanish hasta la muerte and English to death constructions of this type involve two completely distinct syntactic configurations, and that only the English to death PP can be regarded as a resultative phrase. We claim that the Spanish hasta PP is syntactically computed as an adjunct external to the argument structure of the predicate and provides a boundary to the predicate it merges with. We thus show that the Spanish construction with hasta la muerte fully conforms to the class of Talmy’s verb-framed languages in that this type of construction is expected to be fully available and productive in this class of languages.

On the recent claim of correlation between radioactive decay rates and space weather

In recent literature, several authors have challenged the validity of the exponential-decay law, based on observed variations in radioactive decay rate measurements beyond statistical accuracy. Tentative explanations have been sought in external interferences influencing the decay process, such as interactions of the nuclei with solar and cosmic neutrinos. Given the important implications of such statements on theoretical and practical level, one would expect that they are backed up with radionuclide metrology of the highest quality. In reality, they share the common traits of using poor metrology and incomplete uncertainty analysis with respect to the stability of the measurement technique. In this paper, new claims of correlations between decay rates and space weather are questioned.

A Revised Computational Neuroanatomy for Motor Control

We discuss a new framework for understanding the structure of motor control. Our approach integrates existing models of motor control with the reality of hierarchical cortical processing and the parallel segregated loops that characterize cortical–subcortical connections. We also incorporate the recent claim that cortex functions via predictive representation and optimal information utilization. Our framework assumes that each cortical area engaged in motor control generates a predictive model of a different aspect of motor behavior. In maintaining these predictive models, each area interacts with a different part of the cerebellum and BG. These subcortical areas are thus engaged in domain-appropriate system identification and optimization. This refocuses the question of division of function among different cortical areas. What are the different aspects of motor behavior that are predictively modeled? We suggest that one fundamental division is between modeling of task and body whereas another is the model of state and action. Thus, we propose that the posterior parietal cortex, somatosensory cortex, premotor cortex, and motor cortex represent task state, body state, task action, and body action, respectively. In the second part of this review, we demonstrate how this division of labor can better account for many recent findings of movement encoding, especially in the premotor and posterior parietal cortices.