Transition Vector Research Articles

Asymmetric multi-scale systemic risk spillovers across international commodity futures markets: The role of infectious disease uncertainty

This paper investigates the role of infectious disease uncertainty on multi-scale risk spillovers and portfolio implications across 12 international commodity futures markets from January 2006 to August 2022. We use wavelet packet decomposition and a novel risk spillover network topology approach based on a smooth transition vector autoregression model. The main findings are summarized as follows. First, there is an obvious asymmetry in spillover effects, i.e., the intensity of risk spillovers increases significantly during periods of high infectious disease uncertainty, and clear evidence of time-varying total spillovers across various regimes and frequencies. Second, cross-category risk spillovers are more pronounced in high-uncertainty regimes, while risk networks tend to cluster within the same category during low-uncertainty regimes. Third, the role of commodity futures in the risk spillover networks varies across different time scales and regimes, with gold consistently acting as a stable net risk transmitter. We also develop optimal portfolio strategies across commodity futures markets at different time scales and regimes based on the risk spillover analysis.

Altered Dynamic Brain Functional Network Connectivity Related to Visual Network in Spinal Cord Injury.

Visual feedback training (VFT) plays an important role in the motor rehabilitation of patients with spinal cord injury (SCI). However, the neural mechanisms are unclear. We aimed to investigate the changes in dynamic functional network connectivity (FNC) related to visual networks (VN) in patients with SCI and to reveal the neural mechanism of VFT promoting motor function rehabilitation. Dynamic FNC and the sliding window method were performed in 18 complete SCI (CSCI), 16 patients with incomplete SCI (ISCI), and 42 healthy controls (HCs). Then, k-mean clustering was implemented to identify discrete FNC states, and temporal properties were computed. The correlations between these dynamic features and neurological parameters in all patients with SCI were calculated. The majority of aberrant FNC was manifested between VN and executive control network (ECN). In addition, compared with HCs, temporal metrics derived from state transition vectors were decreased in patients with CSCI including the mean dwell time and the fraction of time spent in state 3. Furthermore, the disrupted FNC between salience network and ECN in state 2 and the number of transitions were all positively correlated with neurological scores in patients with SCI. Our findings indicated that SCI could result in VN-related FNC alterations, revealing the possible mechanism for VFT in rehabilitation of patients with SCI and increasing the training efficacy and promoting rehabilitation for SCI.

Развитие системы поддержки одаренных детей в СССР и в России: направления и перспективы

The article examines the work with gifted children in Russia within the context of the historical development of the Russian education system. The aim of the research is to identify the characteristics, directions, and prospects for working with gifted children in Russia within the framework of extensive and intensive development paths. The research involved exploring legislative acts, projects related to working with children, pedagogical papers on the issue of giftedness; methods of analysis and generalization were applied. The scientific novelty of the research lies in predicting possible directions for the development of the Olympiad system, considering its system-forming function. As a result, it can be said that after the collapse of the USSR, the Russian system of additional education has outlined a vector of transition from an extensive to an intensive approach in working with gifted children through regional centers for identifying and supporting such children. At the same time, the system of working with gifted children retains its historical characteristics of an extensive approach in all directions, while the scale of working with gifted children increases: (1) in the Olympiad system, (2) in additional education, and also (3) in the in-depth study of subjects in general education institutions for gifted children. Among the possible directions and prospects are the improvement of the “triangle” of support for gifted children (Olympiads – schools – additional education) in the humanities, for example, by clarifying the status of general education organizations with in-depth study of socio-humanitarian subjects in relation to working with gifted children and realizing the possibilities of a variable nature of the current Olympiad system, which allows children to demonstrate their giftedness in a wide range of activities and academic subjects.

Use and Occupation of the Hydrographic Micro-Basin of Igarapé do Mariano in the Municipality of Manaus-Amazonas

Objective: To analyze the dynamics of the use and occupation of land based on the planning and sustainability of natural resources at the micro-basin of Igarapé do Mariano. Method: This study is characterized by a quali-quantitative approach based on field-collected primary data, followed by data treatment in a laboratory and data analysis in an office. It presents an exploratory nature, with research and information regarding a micro-basin. Results and conclusion: The urban expansion of Manaus advances towards the Mariano micro-basin, likely leading to an intensified use and occupation of land. The recent interventions on the routes and areas of leisure at the riverbed have been provoking negative environmental impacts that are typical of the urban micro-basins of Manaus, which have been and continue being destroyed as the city expands. Implications of the research: Based on the realizations from the analyses of the use and occupation of land, the research is expected to contribute to a planning policy for the territory, be it the Mariano micro-basin or other geographical areas. Originality/value: The study’s value lies on the peculiar location of the studied area, which is situated in the transition vector of urban expansion; on the lack of studies and of deeper information on the subject; on the use of a Remotely Piloted Aircraft in the field work for the photographic and aerophotogrammetric survey, which has proven to be an effective support for the study of the geographical area. All these aspects are of high relevance to the acquired knowledge and could potentially contribute to socioenvironmental actions.

Extended Kalman Filter-Based Vehicle Tracking Using Uniform Planar Array for Vehicle Platoon Systems.

We develop an extended Kalman filter-based vehicle tracking algorithm, specifically designed for uniform planar array layouts and vehicle platoon scenarios. We first propose an antenna placement strategy to design the optimal antenna array configuration for precise vehicle tracking in vehicle-to-infrastructure networks. Furthermore, a vehicle tracking algorithm is proposed to improve the position estimation performance by specifically considering the characteristics of the state evolution model for vehicles in the platoon. The proposed algorithm enables the sharing of corrected error transition vectors among platoon vehicles, for the purpose of enhancing the tracking performance for vehicles in unfavorable positions. Lastly, we propose an array partitioning algorithm that effectively divides the entire antenna array into sub-arrays for vehicles in the platoon, aiming to maximize the average tracking performance. Numerical studies verify that the proposed tracking and array partitioning algorithms improve the position estimation performance.

Space as a scaffold for rotational generalisation of abstract concepts

Learning invariances allows us to generalise. In the visual modality, invariant representations allow us to recognise objects despite translations or rotations in physical space. However, how we learn the invariances that allow us to generalise abstract patterns of sensory data (‘concepts’) is a longstanding puzzle. Here, we study how humans generalise relational patterns in stimulation sequences that are defined by either transitions on a nonspatial two-dimensional feature manifold, or by transitions in physical space. We measure rotational generalisation, i.e., the ability to recognise concepts even when their corresponding transition vectors are rotated. We find that humans naturally generalise to rotated exemplars when stimuli are defined in physical space, but not when they are defined as positions on a nonspatial feature manifold. However, if participants are first pre-trained to map auditory or visual features to spatial locations, then rotational generalisation becomes possible even in nonspatial domains. These results imply that space acts as a scaffold for learning more abstract conceptual invariances.

Space as a scaffold for rotational generalisation of abstract concepts.

Learning invariances allows us to generalise. In the visual modality, invariant representations allow us to recognise objects despite translations or rotations in physical space. However, how we learn the invariances that allow us to generalise abstract patterns of sensory data ('concepts') is a longstanding puzzle. Here, we study how humans generalise relational patterns in stimulation sequences that are defined by either transitions on a nonspatial two-dimensional feature manifold, or by transitions in physical space. We measure rotational generalisation, i.e., the ability to recognise concepts even when their corresponding transition vectors are rotated. We find that humans naturally generalise to rotated exemplars when stimuli are defined in physical space, but not when they are defined as positions on a nonspatial feature manifold. However, if participants are first pre-trained to map auditory or visual features to spatial locations, then rotational generalisation becomes possible even in nonspatial domains. These results imply that space acts as a scaffold for learning more abstract conceptual invariances.

Does household debt affect the size of the fiscal multiplier?

Abstract Does household debt affect the size of the fiscal multiplier? We investigate the effects of household debt on government spending multipliers using a smooth transition vector autoregression model. Through generalized impulse response functions, we measure whether the effect of government spending on GDP is conditioned by different levels of household debt in Australia, Sweden, and Norway, three countries with high levels of household indebtedness, and in the world’s seven largest economies. Our results indicate that the short-term effects of government spending tend to be higher if fiscal expansion takes place during periods of low household debt. On average, the fiscal multiplier (on impact) is 0.70, 0.61, and 0.79 (percent of GDP) larger when the increase in government spending takes place during periods of low household debt for Australia, Norway, and the United States.

Phase transitions in 2D multistable mechanical metamaterials via collisions of soliton-like pulses

In recent years, mechanical metamaterials have been developed that support the propagation of an intriguing variety of nonlinear waves, including transition waves and vector solitons (solitons with coupling between multiple degrees of freedom). Here we report observations of phase transitions in 2D multistable mechanical metamaterials that are initiated by collisions of soliton-like pulses in the metamaterial. Analogous to first-order phase transitions in crystalline solids, we observe that the multistable metamaterials support phase transitions if the new phase meets or exceeds a critical nucleus size. If this criterion is met, the new phase subsequently propagates in the form of transition waves, converting the rest of the metamaterial to the new phase. More interestingly, we numerically show, using an experimentally validated model, that the critical nucleus can be formed via collisions of soliton-like pulses. Moreover, the rich direction-dependent behavior of the nonlinear pulses enables control of the location of nucleation and the spatio-temporal shape of the growing phase.

Enhanced chiroptical activity for narrow deep-blue emission in axial chiral frameworks via three-dimensional interlocking.

The advancement of desirable circularly polarized luminescence (CPL) emitters is predominantly constrained by the effective regulation of magnetic and electric transition vectors, particularly within the deep-blue spectral domain. Herein, we present four pairs of novel chiral emitters with systematically varied molecular rigidity, symmetry, and chiral centers to elucidate the intrinsic coupling of key molecular parameters influencing their chiroptical properties. Notably, the incorporation of appropriate intramolecular 3D-interlocking within a natural binaphthyl chirality skeleton offers an effective approach to achieving both significantly narrowed full width at half maximum (FWHM, as low as 18 nm) and substantially enhanced chiroptical activity (luminous dissymmetry factor, g PL, up to 3.0 × 10-3). Additionally, introducing a secondary chiral center closely parallel to the primary chiral plane facilitates strong chiral-chiral interactions, further affording a 50% improvement in their g PL values. As a demonstration, vacuum-deposited circularly polarized organic light-emitting diodes incorporating these pure fluorescent emitters exhibit outstanding electroluminescent performance, with maximum external quantum efficiency exceeding 5.35%, favorable FWHM of approximately 25 nm, and extreme CIE y values below 0.03.

Spectrum-Aware Transitive On-Demand Routing Protocol for Military Cognitive Radio Ad Hoc Networks

The advancement of wireless technology is increasing the demand for scarce spectrum. Cognitive radio ad hoc networks (CRAHNs) were proposed as a solution to spectrum scarcity which is also deployed in combat. However, military cognitive radio ad-hoc networks (MCRAHNs) are subject to destruction and frequent link breakages. The challenge with MCRAHNs routing is the timing-out of packets. This paper proposes the spectrum-aware transitive multi-cast on-demand distance vector (SAT-MAODV), optimised for throughput and delay. The relay nodes are selected based on zonal data and mobility. This is achieved through handshaking and sharing of location data. The nodes are expected to store location data of nodes encountered, which is used in routing and in determining the movement of the node. The mobility of military nodes is organised and structured, which simplifies routing. The SAT-MAODV was evaluated in network simulator 2 and the results show that the scheme is effective. UsingSAT-MAODV instead of xWCETT reduced routing path and node relay delay by at least 65% and 13% respectively, and increased achievable throughput by 31%. It also improved the delivery ratio by 9% while reducing latency by 27% in comparison with MARSA.

Real estate uncertainty and financial conditions over the business cycle

We investigate the nonlinear effects of real estate uncertainty shocks and the role of financial conditions in the U.S. over the business cycle. We employ a logistic smooth transition vector autoregressive (LSTVAR) model and identify uncertainty shocks through short-run restrictions. The results illustrate that real estate uncertainty shocks negatively affect the housing market, reducing housing prices, housing starts, and employment in the construction sector. The influence of these shocks is notably more pronounced during recessions when compared to results from a standard linear VAR model in terms of the magnitude and persistence of the responses of the housing market-related variables. Additionally, favorable financial conditions dampen the dynamic responses of both macroeconomic indicators and the housing market to real estate uncertainty.

Nonlinear exchange rate pass-through and monetary policy credibility: Evidence from Korea

Applying a smooth transition vector autoregression model with survey expectation data, we investigate the nonlinear effects of exchange rate shocks on inflation across monetary policy credibility states in Korea. We find that the impact of the exchange rate shocks is statistically larger in the low credibility regime, particularly in the short run. Our findings suggest that monetary policy credibility plays a significant role in maintaining for price stability in Korea.

ECO-INTEGRATIVE TERRITORIAL EVOCATION BY EMERGING NEW ARCHITECTURAL ECO-CLIMATIC STYLE

In this research work, the interest is directed towards the evocation of innovative neo-architectural dynamics in the Tunisian south-east territory, through an eco-integrative approach and the production of new eco-climatic architectural styles, based on the natural and cultural wealth of the Tunisian territory, authentic and revolutionary, yet marginalized and restricted, giving rise to reactions to the question that arises: “Is the situation of the vernacular heritage in the Tunisian south-east the direct result of a lack of vernacular heritage potential knowledge lack or of a modernist, restricted and reductive architectural production?” A multi-scale architectural study of rustic heritage has been developed, including a morpho-metric study, the analysis of hygrothermal diagrams produced in situ as well as the measurement of temperature and humidity inside the spaces. Neotroglodytic architecture, allows to highlight the intelligible integration of this new architectural mode in the mineral and arid desert landscape and to detect the aspect of an ecological and sustainable architecture, offering a humble, comfortable and welcoming intra-spatial atmosphere. Otherwise, in southeastern Tunisia, diagnostics have shown that rural villages, partially occupied and exploited in an anarchic manner, are subject to real dangers that threaten their survival in the Saharan territory, considered a difficult area. Direct consequences of an unsuitable development process, these historic works are perceived as static in the face of a dynamic social process, which has led to the gradual increase in their abandonment rates. Similarly, a disfigurement of the rustic landscape results from poor adaptation due to the standardized reproduction of architectural styles “in search of modernity”. The new troglodyte modes present a versatile and capacitive cultural potential. The manifestation of cultural and spatial wealth thus emerges, with the lasting potential of constituting a vector of cultural transition for the territorial development of southeastern Tunisia.

Higher-order memory guided temporal random walk for dynamic heterogeneous network embedding

Network embedding (NE) aims at learning node embeddings via structure-based sampling. However, there are complex patterns in network structure (heterogeneity, higher-order dependence, dynamics) in the real world. The existing methods suffer from high dependence and constraints on manually designed higher-order structures and loss of fine-grained temporal information. To solve the above challenges, we propose a novel higher-order memory guided temporal random walk for dynamic heterogeneous network embedding (HoMo-DyHNE). The proposed model is a two-stage architecture consisting of a meta-structure-independent random walk algorithm namely HoMo-TRW with transition vectors and higher-order memory, and a Hawkes-based featured Skip-gram (HFSG) incorporating a multivariate Hawkes point process to measure the history-current association intensity. Extensive experiments demonstrate the superior effectiveness of our proposed method.

Bee species perform distinct foraging behaviors that are best described by different movement models

In insect-pollinated plants, the foraging behavior of pollinators affects their pattern of movement. If distinct bee species vary in their foraging behaviors, different models may best describe their movement. In this study, we quantified and compared the fine scale movement of three bee species foraging on patches of Medicago sativa. Bee movement was described using distances and directions traveled between consecutive racemes. Bumble bees and honey bees traveled shorter distances after visiting many flowers on a raceme, while the distance traveled by leafcutting bees was independent of flower number. Transition matrices and vectors were calculated for bumble bees and honey bees to reflect their directionality of movement within foraging bouts; leafcutting bees were as likely to move in any direction. Bee species varied in their foraging behaviors, and for each bee species, we tested four movement models that differed in how distances and directions were selected, and identified the model that best explained the movement data. The fine-scale, within-patch movement of bees could not always be explained by a random movement model, and a general model of movement could not be applied to all bee species.

A study of the nonlinear dynamic interrelationship between CO2 emissions and logistics sector output growth

Using provincial panel data spanning from 1995 to 2020, this paper examines the nonlinear interrelationship between logistics carbon dioxide emissions and output growth. For this purpose, we conduct a nonlinear co-integration test in heterogeneous panels; our results suggests a long-run relationship between these two variables. In contrast, adjustment to the equilibrium is inherently nonlinear. Furthermore, we estimate a panel smooth transition vector error correction model. Our major contributions, as we know, are the first study confirming the existence of a dynamic mechanism between logistics carbon dioxide emissions and regional output growth and the Environmental Kuznets Curve in China. Last, the interaction between logistics carbon dioxide emissions and regional output growth varies over the output growth in Chinese provinces and autonomous regions. Our results highlight the importance of considering possible nonlinearities in analyzing output-carbon dioxide emissions causality nexus and designing energy policies.

The relation between quasars’ optical spectra and variability

Abstract Brightness variation is an essential feature of quasars, but its mechanism and relationship to other physical quantities are not understood well. We aimed to find the relationship between the optical variability and spectral features to reveal the regularity behind the random variation. It is known that a quasar’s Fe ii/Hβ flux ratio and equivalent width of [O iii]5007 are negatively correlated; this is called Eigenvector 1. In this work, we visualized the relationship between the position on this Eigenvector 1 (EV1) plane and how the brightness of the quasars had changed after ∼10 yr. We conducted three analyses, using a different quasar sample in each. The first analysis showed the relation between the quasars’ distributions on the EV1 plane and how much they had changed brightness, using 13438 Sloan Digital Sky Survey quasars. This result shows how brightness changes later are clearly related to the position on the EV1 plane. In the second analysis, we plotted the sources reported as “changing-look quasars” (or “changing-state quasars”) on the EV1 plane. This result shows that the position on the EV1 plane corresponds to the activity level of each source, and the bright or dim states of them are distributed on the opposite sides divided by the typical quasar distribution. In the third analysis, we examined the transition vectors on the EV1 plane using sources with multiple-epoch spectra. This result shows that the brightening and dimming sources move on a similar path and they reach a position corresponding to the opposite activity level. We also found this trend is opposite to the empirical rule that $R_{\rm {Fe\, \small {II}}}$ positively correlated with the Eddington ratio, which has been proposed based on the trends of a large number of quasars. From all these analyses, it is indicated that quasars tend to oscillate between both sides of the distribution ridge on the EV1 plane; each of them corresponds to a dim state and a bright state. This trend in optical variation suggests that significant brightness changes, such as changing-look quasars, are expected to repeat.

There Exist Transitive Piecewise Smooth Vector Fields on $$\mathbb {S}^2$$ but Not Robustly Transitive

It is well known that smooth (or continuous) vector fields cannot be topologically transitive on the sphere $\S^2$. Piecewise-smooth vector fields, on the other hand, may present non-trivial recurrence even on $\S^2$. Accordingly, in this paper the existence of topologically transitive piecewise-smooth vector fields on $\S^2$ is proved, see Theorem \ref{teorema-principal}. We also prove that transitivity occurs alongside the presence of some particular portions of the phase portrait known as {\it sliding region} and {\it escaping region}. More precisely, Theorem \ref{main:transitivity} states that, under the presence of transitivity, trajectories must interchange between sliding and escaping regions through tangency points. In addition, we prove that every transitive piecewise-smooth vector field is neither robustly transitive nor structural stable on $\S^2$, see Theorem \ref{main:no-transitive}. We finish the paper proving Theorem \ref{main:general} addressing non-robustness on general compact two-dimensional manifolds.

Vectors to ore in replacive volcanogenic massive sulphide deposits of the northern Iberian Pyrite Belt: Major and trace element mineral chemistry

As part of a broader characterization and study of vectors to ore in VMS systems of the Iberian Pyrite Belt (IPB, Spain), we have investigated in detail mineral chemistry vectors in a representative replacive deposit hosted in felsic volcanic rocks. At the Aguas Teñidas deposit (northern IPB) the hydrothermal system affected rocks of an originally homogeneous composition extending hundreds of metres beyond its footprint. The major and trace element chemistry of white micas, chlorite and carbonates have been analysed by electron microprobe (EMP) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to characterize geochemical vectors across the extent of the hydrothermal system at Aguas Teñidas.White micas are dominated by muscovite in both regionally altered lithologies and within the hydrothermal system, with coexisting paragonite occurring in a halo beyond the first disseminated pyrite surrounding the stockwork and in the proximal hanging wall. Systematic variations have been observed in FeO/(FeO + MgO) and Na2O/(Na2O + K2O) across the alteration zone.Chlorite is predominantly clinochlore in composition, with chamosite restricted to the centre of the hydrothermal system. In regionally altered lithologied it is characterized by a constantly low Al and AlIV at variable Fe/(Fe + Mg); in rocks influenced by the hydrothermal system it presents higher AlIV and total Al, and a progressive increase in Al, AlIV and Fe/(Fe + Mg) towards its core.Regional carbonates consist of calcite, with additional dolomite forming in proximal rocks. Iron content in dolomite increases towards the centre of the hydrothermal system, with ankeritic compositions becoming dominant.Systematic variations in Ba, Cs, Li, Pb, Rb, Sn, Sr, Tl and Zn have been observed in white micas consistent with a proximal-distal transition (vector). Trends in chlorite have been less well characterized due to analytical limitations, although variations have been observed in the contents of As, Co, Li and Zn.A schematic model has been proposed which accounts for the observed mineralogical and mineral chemistry trends across the hydrothermal footprint of the Aguas Teñidas VMS deposit. Major element signatures in white micas and chlorite are interpreted as having been controlled by the upwards and outwards flow of hot reducing Fe-rich hydrothermal fluids producing a coupled increase in temperature and fluid Fe/(Fe + Mg), and a decrease in fO2, with increasing fluid/rock ratios towards the centre of the stockwork.The data presented herein are not only applicable to VMS exploration in the IPB, but on a broader scale improve our general understanding of vectors to ore in VMS deposits in general.