Unidirectional Movement Research Articles

From stationary to directional transition: a case study in Doñana

ContextDoñana’s landscape is a mosaic of different types of transitions at different spatial and temporal scales. Among them, stationary transitions are relatively stable over time, while directional transitions involve the unidirectional movement of boundaries. The fiftieth anniversary of the Doñana National Park (SW Spain) provided a framework to test the transformation of a biotic transition from stationary to directional.ObjectivesThis study aimed to examine landscape changes along a stationary groundwater-dependent transition, the processes responsible for them, and the consequences for the biotic transition.MethodsThrough detailed photointerpretation, nine land use/land cover categories were mapped at four dates (1971, 1984, 2002, 2019) on a ca. 2 square km plot, and then changes analysed at three levels (interval, category, and transition) using Intensity Analysis. Potential causes including precipitation, groundwater levels, local management and changes in the surroundings were examined to understand the changes.ResultsJuniper woodland, spontaneous pines and mixed shrub categories showed the greatest gains and were most active. In the third interval (2002–19) largest transitions from pond-grassland to several terrestrial categories and the dead of heathlands indicate the encroachment of xeric communities into hygrophytic ones. Observed changes seem to be due to succession, forestry management and extrinsic drivers such groundwater overexploitation in the surroundings of the protected area.ConclusionsThe long-term study of this stationary transition shows the weakening of the factors that controlled its establishment, the loss of its constituent habitats due to groundwater withdrawal, and its conversion into a directional transition.

Interiorization in Scriptural Reading: An Exploration in Biblical Spiritual Hermeneutics

The paper explores interiorization as a method in Scriptural reading. The reader looks into the movement in the scriptural text as one pays attention to the interiorization of God’s reality in the human person. However, it is not an unidirectional inward movement but a receptivity that leads to responsiveness and responsibility. The movements, moments, and layers of interiorization unfold through the examination of Hebrew terms - Shema, Hesed, Hakkadosh, Hineni, Emunah, Teshuvah, Yirah, and Tamim.
 The paper provides the visual representation and translates the dynamics of interiorization in the reciprocal spiritual relation into Scriptural Reading through frames of questions. Through the phenomenological method and dialogic reading, the paper intends to broaden the understanding of interiorization and its application within the framework of Biblical Spiritual Hermeneutics.

Principle of CoS2/ZnIn2S4 heterostructure effect and its mechanism of action in a visible light-catalyzed antibacterial process

The development of visible-light-driven catalytic antimicrobial technology is a significant challenge. In this study, heterojunctions were constructed for the appropriate modification of semiconductor-based photocatalysts. A simple hydrothermal method was used for material reconstruction, and smaller CoS2 nanoparticles were deposited and in situ grown on two-dimensional nanoflower-like ZnIn2S4 carriers to form CoS2/ZnIn2S4 (CS/ZIS) Schottky heterojunctions. Systematic study via characterization techniques and density functional theory calculations indicated that the excellent photocatalytic activity of CS/ZIS stemmed from the solid interfacial coupling between the two solid-phase materials. These materials acted as co-catalysts to increase the number of active reaction sites, enhance charge transfer, drive unidirectional electron movement, and improve charge separation efficiency, which effectively facilitated the production of reactive oxygen species (ROS). The optimized CS/ZIS heterojunction exhibited excellent performance for the efficient photocatalytic degradation of organic matter and inactivation of Escherichia coli (E. coli) compared with the ZnIn2S4 photocatalyst. Moreover, the antibacterial mechanism of the heterojunction photocatalyst and the extent of damage to the cell membrane and internal cytoplasm were explored by performing various assays. It was demonstrated that superoxide radicals are the predominant active species and multiple ROS act together to cause oxidative stress damage and cell inactivation.

A scale-coupled numerical method for transient close-contact melting

We introduce a numerical workflow to model and simulate transient close-contact melting processes based on the space-time finite element method. That is, we aim at computing the velocity at which a forced heat source melts through a phase-change material. Existing approaches found in the literature consider a thermo-mechanical equilibrium in the contact melt film, which results in a constant melting velocity of the heat source. This classical approach, however, cannot account for transient effects in which the melting velocity adjusts itself to equilibrium conditions. With our contribution, we derive a model for the transient melting process of a planar heat source. We iteratively cycle between solving for the heat equation in the solid material and updating the melting velocity. The latter is computed based on the heat flux in the vicinity of the heat source. The motion of the heated body is simulated via the moving mesh strategy referred to as the Virtual Region Shear-Slip Mesh Update Method, which avoids remeshing and is particularly efficient in representing unidirectional movement. We show numerical examples to validate our methodology and present two application scenarios, a 2D planar thermal melting probe and a 2D hot-wire cutting machine.

Rheotaxis in Mycoplasma gliding.

This review describes the upstream-directed movement in the small parasitic bacterium Mycoplasma. Many Mycoplasma species exhibit gliding motility, a form of biological motion over surfaces without the aid of general surface appendages such as flagella. The gliding motility is characterized by a constant unidirectional movement without changes in direction or backward motion. Unlike flagellated bacteria, Mycoplasma lacks the general chemotactic signaling system to control their moving direction. Therefore, the physiological role of directionless travel in Mycoplasma gliding remains unclear. Recently, high-precision measurements under an optical microscope have revealed that three species of Mycoplasma exhibited rheotaxis, that is, the direction of gliding motility is lead upstream by the water flow. This intriguing response appears to be optimized for the flow patterns encountered at host surfaces. This review provides a comprehensive overview of the morphology, behavior, and habitat of Mycoplasma gliding, and discusses the possibility that the rheotaxis is ubiquitous among them.

East Asian-North American disjunctions and phylogenetic relationships within subtribe Nepetinae (Lamiaceae)

Biogeographic disjunctions, including intercontinental disjunctions, are frequent across plant lineages and have been of considerable interest to biologists for centuries. Their study has been reinvigorated by molecular dating and associated comparative methods. One of the “classic” disjunction patterns is that between Eastern Asia and North America. It has been speculated that this pattern is the result of vicariance following the sundering of a widespread Acrto-Teritary flora. Subtribe Nepetinae in the mint family (Lamiaceae) is noteworthy because it contains three genera with this disjunction pattern: Agastache, Dracocephalum, and Meehania. These disjunctions are ostensibly the result of three separate events, allowing for concurrent testing of the tempo, origin, and type of each biogeographic event. Using four plastid and four nuclear markers, we estimated divergence times and analyzed the historical biogeography of Nepetinae, including comprehensive sampling of all major clades for the first time. We recover a well-supported and largely congruent phylogeny of Nepetinae between genomic compartments, although several cases of cyto-nuclear discordance are evident. We demonstrate that the three disjunctions are pseudo-congruent, with unidirectional movement from East Asia at slightly staggered times during the late Miocene and early Pliocene. With the possible exception of Meehania, we find that vicariance is likely the underlying driver of these disjunctions. The biogeographic history of Meehania in North America may be best explained by long-distance dispersal, but a more complete picture awaits deeper sampling of the nuclear genome and more advanced biogeographical models.

A cell membrane model that reproduces cortical flow-driven cell migration and collective movement.

Many fundamental biological processes are dependent on cellular migration. Although the mechanical mechanisms of single-cell migration are relatively well understood, those underlying migration of multiple cells adhered to each other in a cluster, referred to as cluster migration, are poorly understood. A key reason for this knowledge gap is that many forces-including contraction forces from actomyosin networks, hydrostatic pressure from the cytosol, frictional forces from the substrate, and forces from adjacent cells-contribute to cell cluster movement, making it challenging to model, and ultimately elucidate, the final result of these forces. This paper describes a two-dimensional cell membrane model that represents cells on a substrate with polygons and expresses various mechanical forces on the cell surface, keeping these forces balanced at all times by neglecting cell inertia. The model is discrete but equivalent to a continuous model if appropriate replacement rules for cell surface segments are chosen. When cells are given a polarity, expressed by a direction-dependent surface tension reflecting the location dependence of contraction and adhesion on a cell boundary, the cell surface begins to flow from front to rear as a result of force balance. This flow produces unidirectional cell movement, not only for a single cell but also for multiple cells in a cluster, with migration speeds that coincide with analytical results from a continuous model. Further, if the direction of cell polarity is tilted with respect to the cluster center, surface flow induces cell cluster rotation. The reason why this model moves while keeping force balance on cell surface (i.e., under no net forces from outside) is because of the implicit inflow and outflow of cell surface components through the inside of the cell. An analytical formula connecting cell migration speed and turnover rate of cell surface components is presented.

Dynamically adjustable wet ridge for directional liquid movement and controllable coating distribution

Controllable wettability on the surface is widely used in architecture coating, energy transfer, microfluidics, etc. Much progress has been focused on liquid wetting state transition of the artificial surface by external induction, while it is still difficult to realize in situ reversible and controllable transformation of the wetting state in real-time to meet the requirement for complex practical applications. Herein, inspired by the unique functions of the superhydrophobic self-cleaning lotus leaf and long-term preservation of rose petal resulting from special wetting states, we achieve the real-time unidirectional movement of droplet on superhydrophobic ZnO nanoarrays surface via the dynamically adjustable wet ridge. By changing the height of the nanorod and the wetting direction of the solvent, the dynamic wet ridge occurs and controls the existence of air in nanostructure, that is, symmetrical wet ridge can realize in situ reversible wetting state transition, while asymmetrical wet ridge can drive water droplet to move. Based on this, the strategy can be used to effectively adjust wettability of coating solution on superhydrophobic surface and to further obtain controllable coating distribution. This work offers an available strategy to achieve real-time droplet movement and controllable complex coating even on structurally challenging substrate, so as to provide opportunities and positive effects for designing functional materials and devices.

An automated approach for counting groups of flying animals applied to one of the world's largest bat colonies

AbstractEstimating animal populations is essential for conservation. Censusing large congregations is especially important since these are priorities for protection, but efficiently counting hundreds of thousands of moving animals remains a challenge. We developed a deep learning‐based system using consumer cameras that not only counts but also records behavioral information for large numbers of flying animals in a range of lighting conditions including near darkness. We built a robust training set without human labeling by leveraging data augmentation and background subtraction. We demonstrate this approach by estimating the size of a straw‐colored fruit bat (Eidolon helvum) colony in Kasanka National Park, Zambia with cameras encircling the colony to record evening emergence. Detection of bats was robust to deteriorating lighting conditions and changing backgrounds. Combined over five days, our population estimates ranged between 750,000 and 976,000 bats with a mean of 857,233. In addition to counts, we extracted wingbeat frequency, flight altitude, and local group polarity for 639,414 individuals. This open access method is an inexpensive but powerful approach that, in addition to radial emergences from central locations, can also be applied to unidirectional movements of flying groups, such as migratory streams of birds.

Co‐temporality and Sovremennost': Late Imperial and Early Soviet Photographs

Co‐temporality and <i>Sovremennost'</i>: Late Imperial and Early Soviet Photographs

The financial mechanism of subordinate educational institutions of the Ministry of Culture of the Russian Federation: Theoretical aspects of functioning

Subject. This article discusses the theoretical aspects of the functioning of the financial mechanism of subordinate educational institutions of the Ministry of Culture of the Russian Federation. Objectives. Based on the concept of two-level modeling of economic systems, the article aims to formulate the content of the concept of Financial Mechanism of Subordinate Educational Institutions of the Ministry of Culture of the Russian Federation, substantiate the composition of its elements, and describe the algorithm of interaction between its constituent elements when financing the institutions. Methods. For the study, we used the author-developed concept of two-level modeling of economic systems. Results. The article finds that the financial mechanism of subordinate educational institutions of the Ministry of Culture of the Russian Federation should be built on the basis of the highlighted feature, namely the unidirectional movement of financial flows from the sources of revenue formation of the State-funded organization to their consumers. The article presents a schematic model of the financial mechanism where administrators and consumers of budget funds are indicated as constituent elements. Relevance. The presented financial mechanism will help budget administrators optimize the budget planning process and increase the effectiveness of control over the movement of financial resources and their targeted use, as well as help subordinate educational institutions of the Ministry of Culture of the Russian Federation create an optimal structure for managing budget funds and increase the efficiency of using budget resources.

Green EEG energy control robot for supporting bedfast patients

The objectives of this study were (1) to develop a prototype for controlling the movements of a robot by using green electroencephalography (EEG) energy and (2) to test a prototype algorithm’s effectiveness for controlling robot movements. The study was conducted as experimental research. An EEG detects electrical energy from activities of the brain and nervous system. The brain’s electrical energy or EEG is produced by thinking or the mind controlling, blinking, meditating, and focusing. The raw acquired EEG data underwent preprocessing and feature extraction. The acquired EEG signals were used to control the robot. Algorithms were designed and developed to connect the EEG data and the robot. The effectiveness of the prototype algorithm in controlling a robot to perform unidirectional movement was determined. The algorithm achieved an accuracy of 81.43%. Likewise, an evaluation of the effect of the prototype algorithm in controlling a robot to perform continuous movement was performed. The algorithm was modified and combined with a gyroscope accelerometer magnetic sensor (IMU) node in a hybrid manner. The experimental result presented 80.22% accuracy, and the algorithm worked properly and consumed 2.40 min of time. The results indicated that the EEG algorithm could correctly control robot movements.

A Preliminary Study on the Functionality of the Carotid-Vertebral Anastomotic Artery in the Regulation of Blood Flow in the Giraffe (Giraffa camelopardalis) by Duplex Ultrasound Examination

Postural change intermittently between upright and head down in giraffes standing at a height of 4.5 meters is of physiological significance. The length of a giraffe’s neck denotes the flow of blood against the force of gravity, to supply the brain over a 2 m distance. The force of gravity also affects the flow of blood toward the brain, with a posture change from erect to ground level. How do these changes in stance not result in fainting when the head is raised and brain damage when the head is lowered? Giraffe has an advanced interconnection of the common carotid artery and the vertebral artery. The connection is located at the midpoint of the atlas, as indicated by means of computerized tomography and dissection. Duplex ultrasound with Doppler waveform examination showed the unidirectional movement of blood with movement from the vertebral artery into the common carotid artery when the head is erect. The direction of flow allows the provision of blood to the maxillary artery that feeds the rostral epidural rete that supplies to the brain. The flow direction in the carotid-vertebral connection changes when blood moves in the direction of the head along with the force of gravity, when the head is lowered. The rerouting of blood to move from the common carotid into the vertebral artery prevents brain damage. We have confirmed, by utilizing a CT scan, Doppler sonar, and dissection of latex-filled arteries, the existence and blood flow direction within the anastomotic artery associated with variation in posture in the giraffe.

Genome-wide measurement of DNA replication fork directionality and quantification of DNA replication initiation and termination with Okazaki fragment sequencing.

Studying the dynamics of genome replication in mammalian cells has been historically challenging. To reveal the location of replication initiation and termination in the human genome, we developed Okazaki fragment sequencing (OK-seq), a quantitative approach based on the isolation and strand-specific sequencing of Okazaki fragments, the lagging strand replication intermediates. OK-seq quantitates the proportion of leftward- and rightward-oriented forks at every genomic locus and reveals the location and efficiency of replication initiation and termination events. Here we provide the detailed experimental procedures for performing OK-seq in unperturbed cultured human cells and budding yeast and the bioinformatics pipelines for data processing and computation of replication fork directionality. Furthermore, we present the analytical approach based on a hidden Markov model, which allows automated detection of ascending, descending and flat replication fork directionality segments revealing the zones of replication initiation, termination and unidirectional fork movement across the entire genome. These tools are essential for the accurate interpretation of human and yeast replication programs. The experiments and the data processing can be accomplished within six days. Besides revealing the genome replication program in fine detail, OK-seq has been instrumental in numerous studies unravelling mechanisms of genome stability, epigenome maintenance and genome evolution.

An electric molecular motor

Macroscopic electric motors continue to have a large impact on almost every aspect of modern society. Consequently, the effort towards developing molecular motors1–3 that can be driven by electricity could not be more timely. Here we describe an electric molecular motor based on a [3]catenane4,5, in which two cyclobis(paraquat-p-phenylene)6 (CBPQT4+) rings are powered by electricity in solution to circumrotate unidirectionally around a 50-membered loop. The constitution of the loop ensures that both rings undergo highly (85%) unidirectional movement under the guidance of a flashing energy ratchet7,8, whereas the interactions between the two rings give rise to a two-dimensional potential energy surface (PES) similar to that shown by FOF1 ATP synthase9. The unidirectionality is powered by an oscillating10 voltage11,12 or external modulation of the redox potential13. Initially, we focused our attention on the homologous [2]catenane, only to find that the kinetic asymmetry was insufficient to support unidirectional movement of the sole ring. Accordingly, we incorporated a second CBPQT4+ ring to provide further symmetry breaking by interactions between the two mobile rings. This demonstration of electrically driven continual circumrotatory motion of two rings around a loop in a [3]catenane is free from the production of waste products and represents an important step towards surface-bound14 electric molecular motors.

Movement patterns and growth rate of Scotsman Polysteganus praeorbitalis (Sparidae) tagged in the Pondoland Marine Protected Area, Eastern Cape, South Africa

A tag-recapture study was undertaken on Polysteganus praeorbitalis in the Pondoland Marine Protected Area (PMPA) on the east coast of South Africa. A total of 1 042 fish were tagged over a period of 16 years and 255 individuals (24.5%) were recaptured, some of them on multiple occasions. Data analysis showed that 84.7% of recaptured fish remained in relatively small home ranges (-750 m linear distance), while 13.3% abandoned their home ranges and undertook unidirectional movements (of 21-1 211 km) along the KwaZulu-Natal coast in a north-easterly direction, most likely to spawn. While the no-take area of the PMPA provides effective protection for resident fish, the export of adult P. praearbitalis provides strong evidence of the benefits that no-take MPAs can offer to adjacent fisheries. Based on the tag-recapture length data, the growth rate was found to be relatively slow, averaging 46 mm y-1. This growth rate was similar to that determined by a study of ageing using sectioned otoliths. Reliable tag-recapture data can thus be used to provide a valuable means of validating growth rates determined by other methods.

ПРОЦЕНТНА ПОЛІТИКА БАНКІВ У СИСТЕМІ РЕГУЛЮВАННЯ РОЗВИТКУ РИНКУ ФІНАНСОВИХ ПОСЛУГ

The article defines the goal of the NBU's interest policy, which consists in achieving a balance between the levels of inflation, the official discount rate, economic growth and the fulfillment of indicators of monetary security of the country. The article analyzes the dynamics of changes in the official discount rate, overnight loan and deposit rates of the NBU. Their unidirectional movement with the possibility of a slight lag in time lags is shown. A comparison of the average annual values of the NBU discount rate with the level of inflation and the exchange rate of the national monetary unit was made. A closer correlation-regression relationship between the discount rate and exchange rate compared to inflation has been established. Disadvantages of the interest policy related to the negative level of the discount rate relative to inflation are shown. The negative consequences of this situation are related to the formation of false monetary impulses in the market of financial services, distorted expectations regarding the value of real interest rates on loans and securities. Periodization of the interest rate policy of the NBU was carried out, with the allocation of nine stages according to the following characteristics: the trend of changes in the NBU discount rate (reduction, increase), the level of inflation (low, average, high), the change in the hryvnia exchange rate (absent, average, significant), the deviation of inflation from discount rate (positive, negative). The characterization of expansive, restrictive, and crisis stages of the monetary policy of the NBU has been performed. In order to strengthen the effectiveness of the interest rate channel of the transmission mechanism, it is proposed within the framework of inflation targeting: to ensure a closer connection between the level of the discount rate and the change in current and projected inflation in terms of the vector of changes and the positive level in order to form among the subjects of the financial services market the correct guidelines for the long-term trend of change cost of loans, deposits, capital. The following will contribute to the reduction of real interest credit rates: the formation of an investment climate in the state, the development of a competitive environment in the market of financial services, the improvement of legislation on the protection of the rights of their consumers, the overcoming of corruption and the improvement of judicial practice in the field of financial and credit relations.

Lateral line morphology, sensory perception and collective behaviour in African cichlid fish.

The lateral line system of fishes provides cues for collective behaviour, such as shoaling, but it remains unclear how anatomical lateral line variation leads to behavioural differences among species. Here we studied associations between lateral line morphology and collective behaviour using two morphologically divergent species and their second-generation hybrids. We identify collective behaviours associated with variation in canal and superficial lateral line morphology, with closer proximities to neighbouring fish associated with larger canal pore sizes and fewer superficial neuromasts. A mechanistic understanding of the observed associations was provided by hydrodynamic modelling of an artificial lateral line sensor, which showed that simulated canal-based neuromasts were less susceptible to saturation during unidirectional movement than simulated superficial neuromasts, while increasing the canal pore size of the simulated lateral line sensor elevated sensitivity to vortices shed by neighbouring fish. Our results propose a mechanism behind lateral line flow sensing during collective behaviour in fishes.

Pre-implantation mouse embryo movement under hormonally altered conditions.

Pre-implantation embryo movement is crucial to pregnancy success, but the role of ovarian hormones in modulating embryo movement is not understood. We ascertain the effects of altered hormonal environment on embryo location using two delayed implantation mouse models: natural lactational diapause (ND); and artificially induced diapause (AD), a laboratory version of ND generated by ovary removal and provision of supplemental progesterone (P4). Previously, we showed that embryos in a natural pregnancy (NP) first display unidirectional clustered movement, followed by bidirectional scattering and spacing movement. In the ND model, we discovered that embryos are present as clusters near the oviductal-uterine junction for ∼24 h longer than NP, followed by locations consistent with a unidirectional scattering and spacing movement. Intriguingly, the AD model resembles embryo location in NP and not ND. When measuring serum hormone levels, unlike the popular paradigm of reduced estrogen (E2) levels in diapause, we observed that E2 levels are comparable across NP, ND and AD. P4 levels are reduced in ND and highly increased in AD when compared to NP. Further, exogenous administration of E2 or P4 modifies embryo location during the unidirectional phase, while E2 treatment also affects embryo location in the bidirectional phase. Taken together, our data suggest that embryo movement can be modulated by both P4 and E2. Understanding natural hormonal adaptation in diapause provides an opportunity to determine key players that regulate embryo location, thus impacting implantation success. This knowledge can be leveraged to understand pregnancy survival and implantation success in hormonally altered conditions in the clinic.

Untethered unidirectionally crawling gels driven by asymmetry in contact forces

Reversible thermoresponsive hydrogels, which swell and shrink (deswell) in the temperature range of 30° to 60°C, provide an attractive material class for operating untethered soft robots in human physiological and ambient conditions. Crawling has been demonstrated previously with thermoresponsive hydrogels but required patterned or constrained gels or substrates to break symmetry for unidirectional motion. Here, we demonstrate a locomotion mechanism for unidirectionally crawling gels driven by spontaneous asymmetries in contact forces during swelling and deswelling of segmented active thermoresponsive poly(N-isopropylacrylamide) (pNIPAM) and passive polyacrylamide (pAAM) bilayers with suspended linkers. Actuation studies demonstrate the consistent unidirectional movement of these gel crawlers across multiple thermal cycles on flat, unpatterned substrates. We explain the mechanism using finite element simulations and by varying experimental parameters such as the linker stiffness and the number of bilayer segments. We elucidate design criteria and validate experiments using image analysis and finite element models. We anticipate that this mechanism could potentially be applied to other shape-changing locomotors.