Opposite States Research Articles

High-efficiency chiral meta-lens

We present here a compact metasurface lens element that enables simultaneous and spatially separated imaging of light of opposite circular polarization states. The design overcomes a limitation of previous chiral lenses reliant on the traditional geometric phase approach by allowing for independent focusing of both circular polarizations without a 50% efficiency trade-off. We demonstrate circular polarization-dependent imaging at visible wavelengths with polarization contrast greater than 20dB and efficiencies as high as 70%.

Control of Synaptic Plasticity Learning of Ferroelectric Tunnel Memristor by Nanoscale Interface Engineering.

Brain-inspired computing is an emerging field, which intends to extend the capabilities of information technology beyond digital logic. The progress of the field relies on artificial synaptic devices as the building block for brainlike computing systems. Here, we report an electronic synapse based on a ferroelectric tunnel memristor, where its synaptic plasticity learning property can be controlled by nanoscale interface engineering. The effect of the interface engineering on the device performance was studied. Different memristor interfaces lead to an opposite virgin resistance state of the devices. More importantly, nanoscale interface engineering could tune the intrinsic band alignment of the ferroelectric/metal-semiconductor heterostructure over a large range of 1.28 eV, which eventually results in different memristive and spike-timing-dependent plasticity (STDP) properties of the devices. Bidirectional and unidirectional gradual resistance modulation of the devices could therefore be controlled by tuning the band alignment. This study gives useful insights on tuning device functionalities through nanoscale interface engineering. The diverse STDP forms of the memristors with different interfaces may play different specific roles in various spike neural networks.

The shades of grey over blue: A maritime delimitation dogma

Since the advent of the United Nations Convention on the Law of the Sea (UNCLOS), coastal countries have recognised the opportunity of extending their jurisdiction along the natural prolongation of their continental landmass – granting them an unprecedented thrust of economic empowerment. States that ratify UNCLOS are mandated to scientifically establish the continuity of their continental margins, beyond 200 nautical miles (nm). As a prelude to this, coastal states are required to demarcate their maritime boundaries – an exercise often complex and seldom free from disputes with adjoining or opposite states. Two noteworthy decisions in the case of India-Bangladesh and Bangladesh-Myanmar maritime delimitation resulted in the inception of a new terminology in maritime history - the ‘grey area’, a state of ambiguity that continues to exist even after three years of adjudication. This article draws attention to the causative circumstances that led to the development of such a scenario; its ramifications in terms of overlapping rights; while suggesting possible propositions for conflict resolution.

All-dielectric planar chiral metasurface with gradient geometric phase.

Planar optical chirality of a metasurface measures its differential response between left and right circularly polarized (CP) lights and governs the asymmetric transmission of CP lights. In 2D ultra-thin plasmonic structures the circular dichroism is limited to 25% in theory and it requires high absorption loss. Here we propose and numerically demonstrate a planar chiral all-dielectric metasurface that exhibits giant circular dichroism and transmission asymmetry over 0.8 for circularly polarized lights with negligible loss, without bringing in bianisotropy or violating reciprocity. The metasurface consists of arrays of high refractive index germanium Z-shape resonators that break the in-plane mirror symmetry and induce cross-polarization conversion. Furthermore, at the transmission peak of one handedness, the transmitted light is efficiently converted into the opposite circular polarization state, with a designated geometric phase depending on the orientation angle of the optical element. In this way, the optical component sets before and after the metasurface to filter the light of certain circular polarization states are not needed and the metasurface can function under any linear polarization, in contrast to the conventional setup for geometry phase based metasurfaces. Anomalous transmission and two-dimensional holography based on the geometric phase chiral metasurface are numerically demonstrate as proofs of concept.

Identification and paleoclimatic significance of magnetite nanoparticles in soils

In the world-famous sediments of the Chinese Loess Plateau, fossil soils alternate with windblown dust layers to record monsoonal variations over the last ∼3 My. The less-weathered, weakly magnetic dust layers reflect drier, colder glaciations. The fossil soils (paleosols) contain variable concentrations of nanoscale, strongly magnetic iron oxides, formed in situ during the wetter, warmer interglaciations. Mineralogical identification of the magnetic soil oxides is essential for deciphering these key paleoclimatic records. Formation of magnetite, a mixed Fe2+/Fe3+ ferrimagnet, has been linked to soil redox oscillations, and thence to paleorainfall. An opposite hypothesis states that magnetite can only form if the soil is water saturated for significant periods in order for Fe3+ to be reduced to Fe2+, and suggests instead the temperature-dependent formation of maghemite, an Fe3+-oxide, much of which ages subsequently into hematite, typically aluminum substituted. This latter, oxidizing pathway would have been temperature, but not rainfall dependent. Here, through structural fingerprinting and scanning transmission electron microscopy and electron energy loss spectroscopy analysis, we prove that magnetite is the dominant soil-formed ferrite. Maghemite is present in lower concentrations, and shows no evidence of aluminum substitution, negating its proposed precursor role for the aluminum-substituted hematite prevalent in the paleosols. Magnetite dominance demonstrates that magnetite formation occurs in well-drained, generally oxidizing soils, and that soil wetting/drying oscillations drive the degree of soil magnetic enhancement. The magnetic variations of the Chinese Loess Plateau paleosols thus record changes in monsoonal rainfall, over timescales of millions of years.

The NapA Antiporter Undergoes Rocking-Bundle Alternation between Oppositely-Facing Conformations: A Simulation Study

Membrane-spanning cation/proton antiporters (CPAs) mediate a vast variety of critical biological processes, and are associated with pathologies ranging from hypertension to autism spectrum disorders, affecting millions worldwide. Though CPAs are widely studied, there is an ongoing debate regarding whether these antiporters alternate between their outward- and inward-facing conformations through an elevator or a rocking-bundle mechanism. The two mechanisms differ in the type of relative motion between the two domains composing the transporter. To address this question, we used molecular dynamics simulations to study the Na+/H+ antiporter NapA from Thermus thermophilus (TtNapA) embedded in a lipid bilayer; TtNapA's structure is known in both inward- and outward-facing states. Specifically, we applied an external potential to TtNapA, to bias the conformational sampling along two axes of motion between the transporter domains. The first was a vertical translation along the membrane normal, consistent with an elevator mechanism; and the second was a tilting movement of one domain relative to the other, consistent with a rocking-bundle mechanism. By applying the bias potential for the two axes simultaneously, as well as for each axis separately, we reproduced each of the known states of TtNapA when starting from the opposite state, with an accuracy of up to 1.7 Angstrom. Importantly, our results suggest that the change between the inward- and the outward-open states depends mainly on the tilting movement rather than on the vertical translation. These results favor the rocking-bundle over the elevator mechanism of the ion/proton antiporting process. Furthermore, applying this approach to the inward-facing conformation of NhaA from Escherichia coli, we sampled what could be its long-sought-after outward-facing conformation.

The Alleged Opposition Deficit in European Union Politics: Myth or Reality?

AbstractAccording to the ‘opposition deficit thesis’ European Union politics is characterized by a conspicuous absence of opposition to the policies promoted by the EU. However, once we start looking for systematic evidence supporting the claim of an opposition deficit in EU politics, we come up surprisingly empty handed. This article seeks to rectify the lacuna in previous research by examining how much and what type of opposition actually exist in EU politics. The study formulates four hypotheses on the state of political opposition in EU politics, and breaks new ground by testing their validity by use of unique data collected from the Swedish European Affairs Committee for the period 1995–2016. The results show there is in fact considerably more opposition present in EU politics than has previously been assumed. The opposition deficit thesis thus seems to be more myth than reality.

Spin-controlled twisted laser beams: intra-cavity multi-tasking geometric phase metasurfaces.

Novel multi-tasking geometric phase metasurfaces were incorporated into a modified degenerate cavity laser as an output coupler to efficiently generate spin-dependent twisted light beams of different topologies. Multiple harmonic scalar vortex laser beams were formed by replacing the laser output coupler with a shared-aperture metasurface. A variety of distinct wave functions were obtained with an interleaving approach - random interspersing of geometric phase profiles within shared-aperture metasurfaces. Utilizing the interleaved metasurfaces, we generated vectorial vortices by coherently superposing of scalar vortices with opposite topological charges and spin states. We also generated multiple partially coherent vortices by incorporating harmonic response metasurfaces. The incorporation of the metasurface platforms into a laser cavity opens a pathway to novel types of nanophotonic functionalities and enhanced light-matter interactions, offering exciting new opportunities for light manipulation.

‘Is There Anybody There?’: Solitude and the Hermeneutics of Love in the Writings of Walter de la Mare

ABSTRACTSolitude and a striving to communicate are major themes in the poetry of Walter de la Mare. While best known for his verse and fiction, de la Mare also produced a series of unconventional anthological works which contain explicit treatments of those themes which are only implicit in his creative work. Drawing on the insights found in these anthologies, this paper argues that, for de la Mare, solitude – along with its opposite state, connectedness – form the endpoints of an axis of concern that is present throughout his body of work. His poetry can be read as an exploration of the infinitely varying degrees of solitude and connection that exist between these two absolute states, manifesting as the possibility of communication held indefinitely in abeyance. Furthermore, in a critical essay on the discourse of love, contained in his 1943 anthological work Love, de la Mare links the themes of solitude, connectedness, and the attendant possibilities of communication, to his deep concern with the problems of language. In doing so, he foreshadows the work of later critics concerning absence and presence in literature, and the possibility of language and meaning in the absence of an addressee, doing so at a time when much of the critical consensus took the communicative efficacy of language for granted.

Non-classical State via Superposition of Two Opposite Coherent States

We study the non-classical properties of the states generated by superpositions of two opposite coherent states with the arbitrary relative phase factors. We show that the relative phase factors plays an important role in these superpositions. We demonstrate this result by discussing their squeezing properties, quantum statistical properties and fidelity in principle.

Tunnel magnetoresistance of ferrocene molecules

The spin transport in ferrocene molecules has been examined by using the nonequilibrium Green’s function formalism with density functional theory. The ferrocene molecules were sandwiched between the two nickel electrodes in a parallel magnetic configuration, which enhanced the current in comparison with that in an antiparallel spin state and resulting in tunnel magnetoresistance (TMR). The current, having an opposite spin state to that of the ferromagnetic electrode, was the main channel for electron transport. In addition, it became clear that ferrocenylene molecules, having a fulvalene structure with an extended π-conjugation, enhanced the TMR effect.

Reciprocal retaliation and local linkage: Federalism as an instrument of opposition organizing in Nigeria

How do local politics shape national political competition in Africa? This article explores opposition party formation in Nigeria, where citizens voted out the People’s Democratic Party in 2015 after 16 years in power. Existing analyses attribute the victory of the All Progressives Congress to issues such as corruption, terrorism, and declining economic performance. Drawing upon field research in Abuja and Rivers, a key opposition state, this article argues that the institutional environment also played a role. Federalism provided the nascent All Progressives Congress with a partisan basis for subnational interest coordination. Rivers’ governor leveraged his authority over local governments to challenge the federal government, linking local struggles to broader states’ rights. The People’s Democratic Party unsuccessfully attempted to deter defections and subvert subnational challenges through court cases and other means. More than just a mechanism for resource distribution, representation, or conflict mediation, Nigeria’s federalism has emerged as an instrument of party organizing.

On the fiscal strategies of escaping poverty-environment traps towards sustainable growth

We develop an overlapping generations (OLG) model with two intermediate inputs, clean and dirty, and one final output in order to consider the interplay between the environment, life expectancy, and capital accumulation, and to consider the possibilities of reallocating capital between the clean and dirty sectors to improve social welfare. We show that the multiple distinct steady states, (and even the continuum of steady state), may occur in a competitive economy. Hence, an economy may fall into a poverty-environment trap that is characterized by low environmental quality, low life expectancy, and therefore, low per capita physical capital, while the others may converge to the opposite steady state. The competitive steady states differ from the first-best steady state in the benevolent social planner’s viewpoint not only because of imperfect altruism between generations in the competitive economy, but also because individuals cannot internalize the effects of their savings (capital accumulation) and capital allocation on environmental quality through producing dirty intermediate inputs, whereas the social planner can. So we propose fiscal strategies towards social planner’s steady state. These fiscal strategies, which are combination of traditional Pigouvian taxes and capital income tax implemented for transition phase are quite new compared to the existing related literature. Although we focus on the transition phase, the proposed taxes are stationary. They include: (i) a set of tax and subsidy imposed on the production of dirty and clean intermediate inputs to improve environmental quality, and therefore, life expectancy and capital accumulation, in order to guarantee that an economy that is locked in a poverty-environment trapcan escape such the stagnation; and (ii) a set of taxes (subsidies) imposed on the production of intermediate inputs and capital income in order to decentralize the transition to the first-best steady state as a competitive outcome.

An unfinished mourning: Kenneth Lonergan’s Manchester by the Sea (2016)

Abstract This article considers the notions of grief and mourning in Kenneth Lonergan’s Manchester by the Sea (2016). The analysis centres on three moments characterized by the coexistence of two opposite states: numbness and an abundance of feelings; immobility and mobility; infidelity and fidelity. To understand each moment, I draw on three philosophical approaches to mourning elaborated by Ralph Waldo Emerson, Roland Barthes and Jacques Derrida. In the first moment, I posit an analogy between the grief experienced by the film’s protagonist Lee and the grief described by Emerson in his essay ‘Experience’. In both cases, grief takes the form of numbness that only masks an abundance of feelings. In the second moment, I apply Barthes’s account of psychic immobility after his mother’s death to the film protagonist’s experience. In the third moment, I analyse Lee’s mourning in relation to Derrida’s concept of ‘possible’ (or ‘successful’) and unsuccessful mourning. Finally, this analysis turns to the question of the bereaved’s loyalty (to the departed, to those who survived and to one’s own grief). Together, these three perspectives reveal a complex, nuanced portrayal of mourning in Manchester by the Sea, which departs from the widespread Freudian understanding of grief and mourning.

Investigating the association between social interactions and personality states dynamics.

The recent personality psychology literature has coined the name of personality states to refer to states having the same behavioural, affective and cognitive content (described by adjectives) as the corresponding trait, but for a shorter duration. The variability in personality states may be the reaction to specific characteristics of situations. The aim of our study is to investigate whether specific situational factors, that is, different configurations of face-to-face interactions, are predictors of variability of personality states in a work environment. The obtained results provide evidence that within-person variability in personality is associated with variation in face-to-face interactions. Interestingly, the effects differ by type and level of the personality states: adaptation effects for Agreeableness and Emotional Stability, whereby the personality states of an individual trigger similar states in other people interacting with them and complementarity effects for Openness to Experience, whereby the personality states of an individual trigger opposite states in other people interacting with them. Overall, these findings encourage further research to characterize face-to-face and social interactions in terms of their relevance to personality states.

A computational study of [formula omitted]-reversible processes on graphs

An f-reversible process on a graph G=(V,E) is a graph dynamical system on V(G) defined as follows. Given a function f:V(G)→N and an initial vertex labeling c0:V(G)→{0,1}, every vertex v changes its label if and only if at least f(v) of its neighbors have the opposite state, synchronously in discrete-time. For such processes, we present a new nondecreasing time function similar to the monotonically decreasing energy functions used to study threshold networks, which leads to a periodic behavior after a transient phase. Using this new function, we provide a tight upper bound on the transient length of f-reversible processes. Furthermore, we prove that it is equal to n−3 for trees with n≥4 vertices and Im(f)={2}. Moreover we present an algorithm that generates all the initial configurations attaining this bound and we prove that the number of such configurations is O(n). We also consider the problem of determining the smallest number rf(G) of vertices with initial label 1 for which all the vertices eventually reach label 1 after the complete evolution of the dynamics, which models consensus problems on networks. We prove that it is NP-hard to compute rf(G) even for bipartite graphs with Δ(G)≤3 and Im(f)={1,2,3}. Finally, we prove that β(G)≤rf(G)≤β(G)+1, when f(v)=d(v) for all v∈V(G), where β(G) is the size of a minimum vertex cover of G.

Precise detection of circular dichroism in a cluster of nano-helices by photoacoustic measurements

Compact samples of nano-helices built by means of a focused ion beam technology with large bandwidth and high dichroism for circular polarization are promising for the construction of built-in-chip sensors, where the ideal transducer must be sufficiently confined without compromising its filtering ability. Direct all-optical measurements revealed the sample’s dichroic character with insufficient details because of scattering and diffraction interference. On the other hand, photoacoustic measurements resulted to be a possible alternative investigation, since they directly deal with absorbed power and allow to get clear evidences of the differential selection for the two opposite polarization states. Multi-level numerical simulations confirmed the experimental results, proving once again the reliability of photoacoustic technique and the versatility of this class of dichroic artificial materials.

A tale of two circuits: CCKNTS neuron stimulation controls appetite and induces opposing motivational states by projections to distinct brain regions

Cholecystokinin (CCK)-expressing neurons within the nucleus of the solitary tract (CCKNTS) of the mouse are responsive to satiety signals and their chemogenetic activation suppresses appetite. Optogenetic activation of CCKNTS axon terminals within either the parabrachial nucleus (PBN) or the paraventricular nucleus of the hypothalamus (PVH) is sufficient to suppress feeding. An interesting dichotomy has been revealed when assessing the motivational valence of these two circuits. Activating CCKNTS cell bodies is aversive as demonstrated by conditioned taste aversion and place-preference assays. Activation of the CCKNTS→PBN pathway is also aversive; however, stimulating the CCKNTS→PVH pathway is appetitive when assayed using a real-time, place-preference task. Thus, these two projections from CCKNTS neurons reduce food intake through opposite motivational states; one pathway signals positive valence (CCKNTS→PVH) and the other signals negative valence (CCKNTS→PBN).

Telic-paratelic Dominance and State Effects on Responses to Resistance and Endurance Exercise

We examined the influence of opposite states of mind (the telic vs. paratelic state) and dominances (personality characteristics that reflect a preference for one of these states) on emotion and stress responses to exercise. Telic dominant participants completing resistance exercise in the telic state condition reported decreased relaxation from pre-to post-exercise. All participants reported more pleasant emotions when performing endurance exercise in the telic state condition. In contrast, in the paratelic state condition, they reported increased anxiety. These results lend mixed support for previous research but suggest that meta-motivational state is more influential than dominance.

Leucine Biosynthesis Is Involved in Regulating High Lipid Accumulation in Yarrowia lipolytica.

ABSTRACTThe yeast Yarrowia lipolytica is a potent accumulator of lipids, and lipogenesis in this organism can be influenced by a variety of factors, such as genetics and environmental conditions. Using a multifactorial study, we elucidated the effects of both genetic and environmental factors on regulation of lipogenesis in Y. lipolytica and identified how two opposite regulatory states both result in lipid accumulation. This study involved comparison of a strain overexpressing diacylglycerol acyltransferase (DGA1) with a control strain grown under either nitrogen or carbon limitation conditions. A strong correlation was observed between the responses on the transcript and protein levels. Combination of DGA1 overexpression with nitrogen limitation resulted in a high level of lipid accumulation accompanied by downregulation of several amino acid biosynthetic pathways, including that of leucine in particular, and these changes were further correlated with a decrease in metabolic fluxes. This downregulation was supported by the measured decrease in the level of 2-isopropylmalate, an intermediate of leucine biosynthesis. Combining the multi-omics data with putative transcription factor binding motifs uncovered a contradictory role for TORC1 in controlling lipid accumulation, likely mediated through 2-isopropylmalate and a Leu3-like transcription factor.