Canonical Position Research Articles

The effect of the Generalized Uncertainty Principle on the motion of particles near a black hole horizon

Abstract We study the behaviour of massive particles under different potentials near a static spherical black hole. Our purposes are to apply the Hamilton–Jacobi method for this study and to investigate the effects of a minimal length on the motion of particles in unstable equilibrium near the black hole horizon by deformation of a canonical position–momentum commutation relation. We also obtain the equation of motion for a particle on a path in a plane by considering the special potential corresponding to the cylindrical horizon. We also discuss the behaviour of particles and their energy in terms of the black hole’s characteristics with different potentials. For both the standard and deformed cases, we examine the changes in the particle’s motion in terms of the potential’s coefficients which correspond to the black hole’s horizon.

The focus function and derivation of object displacement in Standard Arabic

The aim of this paper is to provide a minimalist account of object displacement in terms of its trigger and its landing site in the syntactic tree structure of Standard Arabic (SA) clauses. The account utilizes Chomsky's concept of edge feature (EF) within the Minimalist Program and Rizzi's Split-CP analysis. In terms of its data scope, the paper is limited to a class of data identified as displaying the Verb – Object – Subject (VOS) order wherein the object is a full DP (not a pronominal clitic), and appears in a position preceding the subject. It will be argued that this order is the result of focus displacement of the object from its canonical position inside VP across the subject DP to the outer periphery of vP. The result of this operation is a marked order VOS driven by the vP edge feature (EF) to achieve the pragmatic function of focus.

Theta- and Gamma-Band Activity Discriminates Face, Body and Object Perception

Face and body perception is mediated by configural mechanisms, which allow the perception of these stimuli as a whole, rather than the sum of individual parts. Indirect measures of configural processing in visual cognition are the face and body inversion effects (FIE and BIE), which refer to the drop in performance when these stimuli are perceived upside-down. Albeit FIE and BIE have been well characterized at the behavioral level, much still needs to be understood in terms of the neurophysiological correlates of these effects. Thus, in the current study, the brain’s electrical activity has been recorded by a 128 channel electroencephalogram (EEG) in 24 healthy participants while perceiving (upright and inverted) faces, bodies and houses. EEG data were analyzed in both the time domain (i.e., event-related potentials—ERPs) and the frequency domain [i.e., induced theta (5–7 Hz) and gamma (28–45 Hz) oscillations]. ERPs amplitude results showed increased N170 amplitude for inverted faces and bodies (compared to the same stimuli presented in canonical position) but not for houses. ERPs latency results showed delayed N170 components for inverted (vs. upright) faces, houses, but not bodies. Spectral analysis of induced oscillations indicated physiological FIE and BIE; that is decreased gamma-band synchronization over right occipito-temporal electrodes for inverted (vs. upright) faces, and increased bilateral frontoparietal theta-band synchronization for inverted (vs. upright) faces. Furthermore, increased left occipito-temporal and right frontal theta-band synchronization for upright (vs. inverted) bodies was found. Our findings, thus, demonstrate clear differences in the neurophysiological correlates of face and body perception. The neurophysiological FIE suggests disruption of feature binding processes (decrease in occipital gamma oscillations for inverted faces), together with enhanced feature-based attention (increase in frontoparietal theta oscillations for inverted faces). In contrast, the BIE may suggest that structural encoding for bodies is mediated by the first stages of configural processing (decrease in occipital theta oscillations for inverted bodies).

When does rotation disrupt letter encoding? Testing the resilience of letter detectors in the initial moments of processing.

Previous research has reported that both letter and word identification are slower when the stimuli are presented at rotations above 45° than when presented in their canonical horizontal view. Indeed, influential models of word recognition posit that letter detectors in the visual word recognition system are disrupted by rotation angles above 40° or 45° (e.g., Local Combinations Detector model; Dehaene, Cohen, Sigman, & Vinckier, 2005, Trends in Cognitive Sciences). However, recent experiments have shown robust masked identity/form priming effects for 90° rotated words, thus calling into question this assumption. Here we aimed to isolate the degree to which letter detectors are disrupted when manipulating letter rotation in three masked identity priming letter match experiments. Probes and targets were always presented in the canonical upright position, whereas forwardly masked primes were rotated in different angles. The rotation angles were 0° versus 45° (Experiment 1), 22.5° versus 67.5° (Experiment 2), and 45° versus 90° (Experiment 3). Results showed a sizeable masked identity priming effect regardless of the rotation angle, hence demonstrating that letter detectors are not disrupted by rotations smaller than 90° in the early moments of letter processing. This pattern suggests that letter detectors are more resilient to changes in visual form than predicted by the LCD model.

Subject licensing in non-verbal clauses in Arabic

Abstract This paper investigates the licensing of subjects in Standard Arabic participial clauses. Unlike verbal clauses, whose subject may appear post-verbally, the subject of participial clauses must precede the participle, having properties of topics of verbal clauses. I claim that this is because the canonical subject position, [Spec, vP], is not available for subjects of participles, due to lack of Nom Case. It is shown that neither tense nor a copula is sufficient to license structural Nom Case on a subject in [Spec, vP]. I conclude that the licensing of Nom Case on post-verbal subjects is dependent on V-to-T raising; that is, Nom Case is licensed by the T-V complex. The present account has implications for the nature of pre-verbal subjects in Arabic as well as for the categorial status of copular elements like kāna.

The unique structural features of carbonmonoxy hemoglobin from the sub-Antarctic fish Eleginops maclovinus

Tetrameric hemoglobins (Hbs) are prototypical systems for the investigations of fundamental properties of proteins. Although the structure of these proteins has been known for nearly sixty years, there are many aspects related to their function/structure that are still obscure. Here, we report the crystal structure of a carbonmonoxy form of the Hb isolated from the sub-Antarctic notothenioid fish Eleginops maclovinus characterised by either rare or unique features. In particular, the distal site of the α chain results to be very unusual since the distal His is displaced from its canonical position. This displacement is coupled with a shortening of the highly conserved E helix and the formation of novel interactions at tertiary structure level. Interestingly, the quaternary structure is closer to the T-deoxy state of Hbs than to the R-state despite the full coordination of all chains. Notably, these peculiar structural features provide a rationale for some spectroscopic properties exhibited by the protein in solution. Finally, this unexpected structural plasticity of the heme distal side has been associated with specific sequence signatures of various Hbs.

Single mutation in a novel bacterial LOV protein yields a singlet oxygen generator.

Mr4511 from Methylobacterium radiotolerans is a 164 amino acid protein built of a flavin mononucleotide (FMN) binding, blue-light responsive LOV (Light, Oxygen, Voltage) core domain plus flanking regions. In contrast to the majority of LOV domains, Mr4511 lacks a tryptophan residue that was previously identified as a major quencher for the FMN triplet state in photosensitizers for singlet oxygen (SO) engineered from these photoreceptors. Here we show that for Mr4511 it is sufficient to only mutate the reactive cysteine responsible for the photocycle (Cys71) in the native protein to generate an efficient SO photosensitizer: both C71S and C71G variants exhibit SO quantum yields of formation, ΦΔ, around 0.2 in air-saturated solutions. Under oxygen saturated conditions, ΦΔ reaches ∼0.5 in deuterated buffer. The introduction of Trp112 in the canonical position for LOV domains dramatically lowers ΦΔ to values comparable to miniSOG, one of the early FMN binding proteins touted as a SO sensitizer. Besides its SO properties, Mr4511 is also exceedingly robust against denaturation with urea and is more photostable than free FMN.

Planar Orientation Control and Torque Maximization Using a Swarm With Global Inputs

This paper studies the torque applied by a large number of particles on a long aspect-ratio rod. The particles are all pushed in the same direction by a global signal. We calculate the force and torque generated by three canonical position distributions of a swarm: uniform, triangular, and normal. The model shows that for a pivoted rod the uniform distribution produces the maximum torque for small swarm standard deviations, but the normal distribution maximizes torque for large standard deviations. In the simulation, we use these results to design proportional-derivative controllers to orient rigid objects. We conclude showing the experiments with up to 97 hardware robots to evaluate our theory in practice.

Quirks of subject (non-)extraction in Igbo

In this paper we present new data on a subject/non-subject extraction asymmetry in Igbo constituent questions. We provide evidence that the superficially morphological phenomenon reflects a deeper syntactic asymmetry: Unlike wh-non-subjects, wh-subjects cannot undergo local Ā-movement to the left periphery (SpecFoc); rather, they have to stay in their canonical position SpecT. The same constraint also leads to the that-trace effect (absence of the complementizer) in the embedded clause of long subject wh-movement. We argue that what is responsible for the special status of wh-subjects is their high structural position. We provide an optimality-theoretic analysis of the asymmetry that is based on anti-locality: Local subject Ā-movement is excluded because it is too short. Moreover, we address the nature of apparent wh-in-situ in Igbo.

Postverbal subjects and agreement: specificational copular clauses in Faroese

In this paper we discuss a type of copular clause – specificational copular clauses – in which subject properties may be split between two nominative noun phrases. In particular, while the first noun phrase occupies the canonical preverbal subject position, in some languages the finite verb can agree with the postverbal nominative. Such agreement might be expected, on some theoretical assumptions, to show person restrictions. We discuss this phenomenon in two SVO Germanic languages – Icelandic and Faroese – and present new data from Faroese showing that the person effect here follows from the existence of distinct probes for Number and Person agreement.

Steroid-steroid interactions in biological membranes: Cholesterol and cortisone.

Steroid flares are common side effects associated with corticosteroid treatment, and have been recently theorized to be a consequence of drug crystallization. It was previously reported that the lipid bilayer can promote crystallization of cortisone at high local concentrations. Here, we studied the effect of cholesterol on this membrane induced cortisone crystallization. By combining x-ray diffraction and Molecular Dynamics simulations we observe that that the presence of cholesterol suppresses cortisone-induced membrane thinning and cortisone transnucleation. Cortisone located in the head-tail interface of the membranes also in the presence of cholesterol. The cholesterol molecules were found to be tilted and displaced towards the bilayer center as function of cortisone concentration, away from their canonical position. Our results show that membrane cholesterol may play an important role in the ability of lipid bilayers to catalyze the formation of corticosteroid crystallites.

Variations on a Motive: Hamsun and Tammsaare

In 1935 Ma armastasin sakslast (I Loved a German) was published. In 1928 Victoria (1898) by Knut Hamsun (1859–1952) was published in Estonian. The first was written and the second translated by A. H. Tammsaare (1878– 1940). Parallels between these two authors have been most often discussed in connection with Pan (1894) and Kõrboja peremees (The Master of Kõrboja, 1922). Both authors have earned their canonical position in literature thanks to the novels Markens Grøde (Growth of the Soil) (1917), in the case of Hamsun, and Tõde ja õigus (Truth and Justice, I–V, 1926–1933) in the case of Tammsaare. These novels have been “sorted out” to be included in the canon, while Ma armastasin sakslast and Victoria have not received as much attention. In both novels love is the central theme – in Hamsun’s novel the main characters are the miller’s son Johannes and the landlord’s daughter Victoria, and in Tammsaare’s novel the student Oskar and a baron’s grand daughter, Erika. This article examines the connections between Hamsun and Tammsaare by analysing the novels Victoria and Ma armastasin sakslast, discussing among others the motive that has been widely used in world literature, namely the (archetypical) story of lovers – Romeo and Juliet by Shakespeare. Both novels can be considered as variations on that motive as Tammsaare, for example, adds the social aspect, so that the archetypical love story set in the Republic of Estonia enables him to discuss topics essential to him. In the article the main emphasis is on Tammsaare’s novel.

Complementizer doubling and subject extraction in Italo-Romance

AbstractIn this article I analyze the complementizer doubling construction attested in some early and modern Italo-Romance varieties, where a preposed (clausal or non clausal) constituent associated to the selected clause appears in the embedded left periphery preceded and followed by a subordinating complementizer. While the higher complementizer is uncontroversially interpreted as a lexicalization of the head Force°, the lower complementizer has been taken to lexicalize either the functional head Topic° or the functional head Fin°. Relying on previous formal analyses of subject extraction, I argue that in the varieties in which the lower complementizer lexicalizes Fin°, its presence reflects the lexicalization of the mood features encoded by Fin°, and is ultimately due to the extraction of the thematic subject out of the embedded clause through Spec,FinP, a movement strategy made possible by the presence of an expletiveproin the canonical preverbal subject position.

How broad are thematic roles? Evidence from structural priming

Verbs that are similar in meaning tend to occur in the same syntactic structures. For example, give and hand, which denote transfer of possession, both appear in the prepositional-object construction: “The child gave/handed the ball to the dog.” We can call the child a “giver” in one case and a “hander” in the other, or we can refer to her more generally as the agent, or doer of the action. Similarly, the dog can be called the recipient, and the ball, the theme. These generalized notions of agent, recipient, and theme are known as thematic roles. An important theoretical question for linguists and psycholinguists is what the set of thematic roles is. Are there a small number of very broad roles, perhaps with each one mapping onto a single canonical syntactic position? Or are there many distinct roles, several mapping to the same syntactic position but conveying subtly different meanings? We investigate this question across eleven structural priming experiments on Amazon Mechanical Turk (total N = 2914), asking whether speakers treat the thematic roles recipient and destination (i.e., location or spatial goal) as interchangeable, suggesting the broad role of goal, or distinct, suggesting two separate roles. To do so, we look for priming between dative sentences (e.g., “The man gave the ball to the dog”), which have a recipient role (dog), and locative sentences (e.g., “The man loaded hay onto the wagon”), which instead have a destination role (wagon). Our pattern of findings confirms that thematic role mappings can be primed independent of syntactic structure, lexical content, and animacy. However, we find that this priming does not extend from destinations to recipients (or vice versa), providing evidence that these two roles are distinct.

A remark on Béjar & Kahnemuyipour 2017: Specificational subjects do have phi-features

In a number of languages, agreement in specificational copular sentences can or must be with the second of the two nominals, even when it is the first that occupies the canonical subject position. Béjar & Kahnemuyipour (2017) show that Persian and Eastern Armenian are two such languages. They then argue that ‘NP2 agreement’ occurs because the nominal in subject position (NP1) is not accessible to an external probe. It follows that actual agreement with NP1 should never be possible: the alternative to NP2 agreement should be ‘default’ agreement. We show that this prediction is false. In addition to showing that English has NP1, not default, agreement, we present new data from Icelandic, a language with rich agreement morphology, including cases that involve ‘plurale tantum’ nominals as NP1. These allow us to control for any confound from the fact that typically in a specificational sentence with two nominals differing in number, it is NP2 that is plural. We show that even in this case, the alternative to agreement with NP2 is agreement with NP1, not a default. Hence, we conclude that whatever the correct analysis of specificational sentences turns out to be, it must not predict obligatory failure of NP1 agreement.

Structural basis of transcriptional stalling and bypass of abasic DNA lesion by RNA polymerase II

Abasic sites are among the most abundant DNA lesions and interfere with DNA replication and transcription, but the mechanism of their action on transcription remains unknown. Here we applied a combined structural and biochemical approach for a comprehensive investigation of how RNA polymerase II (Pol II) processes an abasic site, leading to slow bypass of lesion. Encounter of Pol II with an abasic site involves two consecutive slow steps: insertion of adenine opposite a noninstructive abasic site (the A-rule), followed by extension of the 3'-rAMP with the next cognate nucleotide. Further studies provided structural insights into the A-rule: ATP is slowly incorporated into RNA in the absence of template guidance. Our structure revealed that ATP is bound to the Pol II active site, whereas the abasic site is located at an intermediate state above the Bridge Helix, a conserved structural motif that is cirtical for Pol II activity. The next extension step occurs in a template-dependent manner where a cognate substrate is incorporated, despite at a much slower rate compared with nondamaged template. During the extension step, neither the cognate substrate nor the template base is located at the canonical position, providing a structural explanation as to why this step is as slow as the insertion step. Taken together, our studies provide a comprehensive understanding of Pol II stalling and bypass of the abasic site in the DNA template.

Lifting the bandwidth limit of optical homodyne measurement with broadband parametric amplification

Homodyne measurement is a corner-stone method of quantum optics that measures the quadratures of light—the quantum optical analog of the canonical position and momentum. Standard homodyne, however, suffers from a severe bandwidth limitation: while the bandwidth of optical states can span many THz, standard homodyne is inherently limited to the electronically accessible MHz-to-GHz range, leaving a dramatic gap between relevant optical phenomena and the measurement capability. We demonstrate a fully parallel optical homodyne measurement across an arbitrary optical bandwidth, effectively lifting this bandwidth limitation completely. Using optical parametric amplification, which amplifies one quadrature while attenuating the other, we measure quadrature squeezing of 1.7 dB simultaneously across 55 THz, using the pump as the only local oscillator. As opposed to standard homodyne, our measurement is robust to detection inefficiency, and was obtained with >50% detection loss. Broadband parametric homodyne opens a wide window for parallel processing of quantum information.

Shift of Shapiro Step in High Critical Temperature Superconductors

The influence of the charge imbalance effect on a system of intrinsic Josephson junctions of high temperature superconductors under external electromagnetic radiation is investigated. We find that the charge imbalance is responsible for the slope of the Shapiro step in the IV-characteristic. The nonperiodic boundary conditions shift the Shapiro step from the canonical position which is determined by the frequency of the external radiation. We also find how the system parameters influence the shift of the Shapiro step.

Clitics as input to the acquisition of verbal transitivity in French

AbstractWe investigate the effect of French clitic construction on verb learning. In French, object pronouns precede the verb, and the canonical direct object position remains empty. We test whether children treat such contexts as input for transitivity (since a direct object is morphologically identified) or optional transitivity (due to the empty direct object position). Forty-eight monolingual French preschoolers heard verb input with clitics and noun phrases as direct objects, in two input conditions: obligatory transitivity, and mixed optional transitivity. Results show that children are sensitive to the input, but produce more sentences with null implicit objects in the clitic conditions. This provides evidence that specific properties of a language (e.g. clitic constructions), affect the acquisition of verbal classes.

Transitive expletive constructions in Swedish

This article discusses the existence of transitive expletive constructions (TECs) in Swedish. It is often claimed that TECs are a distinctive feature of Insular Scandinavian, but do not exist in Mainland Scandinavian. In this article, however, it is shown that such constructions do occur throughout the history of Swedish and, to some extent, still occur in present-day Swedish, although nowadays the language has none of the features previously proposed as licensing TECs. It is also shown that Swedish has a broader repertoire of associate subjects in TECs than does Icelandic. Unlike in Icelandic, associate subjects can also be definite in Swedish. The presence of TECs in Swedish calls into question the previous analysis of the licensing of this construction, and in this article a new explanation for the phenomenon is proposed. It is claimed that TECs are possible if the expletive can merge in a position structurally higher than the canonical subject position. In the case of V2 languages, this implies that expletives must be able to merge in Spec,CP, and it is shown that in Swedish they are able to merge in this position.