Trail Patterns Research Articles

Soft tissue scavenging patterns of mice on human remains.

Rodent scavenging of human remains is repeatedly documented in literature. However, most of this documentation is based on single-case examples. While this information is valuable, it does not provide an in-depth understanding of scavenger behavior in a single environment. Mouse scavenging data, in particular, lack larger sample sizes and data representing the full duration of scavenging activity. In documented cases, mice scavenge primarily the hands, the feet, and the head without significant progression into the rest of the body. At the Forensic Investigation Research Station in Whitewater, Colorado, deer mice (Peromyscus maniculatus group) scavenged tissue from 11 human donors. Motion activated game cameras and regular field photography documented scavenging progression and deer mouse behavior. Deer mice generally showed a preference for skin and fat, rarely consuming enough muscle to expose bone. The most scavenged sections of the body were the limbs and deer mice generally ignored the hands, the feet, and the head, unlike previous documentation. In a few cases, deer mice consumed tissue on the limbs in a distinct trail pattern. Most of the scavenging began in spring. This sample greatly expands on the existing documentation of mice overall and contributes much needed data on the progression of scavenging. Scavengers can have a significant impact on a death scene, so detailed documentation of different scavengers in a variety of environments can prove useful in the investigation process.

Branched flows in active random walks and the formation of ant trail patterns

Branched flows in active random walks and the formation of ant trail patterns

Differences in High-Quality Development and Its Influencing Factors between Yellow River Basin and Yangtze River Economic Belt

As a national strategy, the development of the Yangtze River Economic Belt (YREB) and the ecological protection and high-quality development (HQD) of the Yellow River Basin (YRB) are of great significance for promoting the HQD of the regional economy. Based on the panel data in the YRB and the YREB from 2006 to 2019, this paper constructed an evaluation index system of HQD with five dimensions of “innovation development, coordination development, green development, openness development, and sharing development”, and we used the entropy weight method, kernel density method, and Tobit panel model to analyze the differences in the HQD and the similarities and differences of the influencing factors between the two regions. The research findings were as follows: (1) The HQD of the YRB and the YREB was consistent with the national trend, showing a fluctuating upward trend. The HQD of the YRB was always lower than that of the YREB. The kernel density curves in both regions had a rightward trailing pattern, with polarization and unbalanced development. (2) From the perspective of the spatial distribution pattern, the HQD of the YRB presented a spatial distribution characteristic of “high at both ends and low in the middle”. In contrast, the HQD of the YREB maintained the characteristic of “high in the east and low in the west”. (3) The level of human capital, the level of foreign direct investment, and the economic scale played a significant positive role in improving the HQD of the YRB. The level of human capital, urbanization, foreign direct investment, and economic scale significantly improved the HQD of the YREB.

Dugong feeding grounds and spatial feeding patterns in subtidal seagrass: A case study at Sibu Archipelago, Malaysia

In Southeast Asia, seagrass meadows are under threat through coastal development and increased pollution, but remain understudied. The dugong is a marine herbivore that is dependent on the availability of seagrass as a primary food source. In this study, we assess the patterns of co-occurrence between dugongs and seagrass. We hypothesize that the changing spatial patterns of dugong feeding are positively correlated to the seasonal variation in distribution and abundance of mixed species in subtidal tropical seagrass meadows. We documented seagrass cover and dugong feeding trails in the Sibu Archipelago meadow in Johor, Malaysia, across the monsoon seasons of 2016–2017 using an underwater towed video method. Moran's I and Getis-Ord Gi* statistics were used to quantify the degree of clustering in feeding trails, feeding patch size, and to identify feeding hotspots and coldspots. This site has the single largest subtidal meadow in Peninsular Malaysia known to date, measuring 12.88 km2. The study captured a reduction in seagrass extent and coverage during the study. Feeding trail occurrence averaged three per image throughout the seasons, with the maximum number being 14 trails per image. Dugongs fed in a spatially clustered manner leaving two distinct feeding trail patterns: (1) a dispersed pattern when seagrass cover was high or low (76–100% and 0–25%) that resulted in larger patch sizes, and (2) a concentrated pattern in moderate seagrass cover (26–75%) that resulted in smaller patch size. Feeding hotspots and coldspots had significantly different seagrass cover, suggesting that dugongs foraged strategically within the meadow. Our results demonstrate that seagrass cover played a significant role in driving dugong feeding patterns and in creating feeding hotspots and coldspots in tropical subtidal meadows.

Dosimetric leaf gap and leaf trailing effect in a double-stacked multileaf collimator.

To investigate (i) the dosimetric leaf gap (DLG) and the effect of the "trailing distance" between leaves from different multileaf collimator (MLC) layers in Halcyon systems and (ii) the ability of the currently available treatment planning systems (TPSs) to approximate this effect. DICOM plans with transmission beams and sweeping gap tests were created in Python for measuring the DLG for each MLC layer independently and for both layers combined. In clinical Halcyon plans both MLC layers are interchangeably used and leaves from different layers are offset, thus forming a trailing pattern. To characterize the impact of such configuration, new tests called "trailing sweeping gaps" were designed and created where the leaves from one layer follow the leaves from the other layer at a fixed "trailing distance" between the tips. Measurements were carried out on five Halcyons SX2 from different institutions and calculations from both the Eclipse and RayStation TPSs were compared with measurements. The dose accumulated during a sweeping gap delivery progressively increased with the trailing distance . We call this "the trailing effect." It is most pronounced for between 0 and 5mm, although some changes were obtained up to 20mm. The dose variation was independent of the gap size. The measured DLG values also increased with up to 20mm, again with the steepest variation between 0 and 5mm. Measured DLG values were negative at =0 (the leaves from both layers at the same position) but changed sign for ≥1mm, in line with the positive DLG sign usually observed with single-layer rounded-end MLCs. The Eclipse TPS does not explicitly model the leaf tip and, as a consequence, could not predict the dose reduction due to the trailing effect. This resulted in dose discrepancies up to +10% and -8% for the 5mm sweeping gap and up to ±5% for the 10mm one depending on the distance . RayStation implements a simple model of the leaf tip that was able to approximate the trailing effect and improved the agreement with measured doses. In particular, with a prototype version of RayStation that assigned a higher transmission at the leaf tip the agreement with measured doses was within ±3% even for the 5mm gap. The five Halcyon systems behaved very similarly but differences in the DLG around 0.2mm were found across different treatment units and between MLC layers from the same system. The DLG for the proximal layer was consistently higher than for the distal layer, with differences ranging between 0.10mm and 0.24mm. The trailing distance between the leaves from different layers substantially affected the doses delivered by sweeping gaps and the measured DLG values. Stacked MLCs introduce a new level of complexity in TPSs, which ideally need to implement an explicit model of the leaf tip in order to reproduce the trailing effect. Dynamic tests called "trailing sweeping gaps" were designed that are useful for characterizing and commissioning dual-layer MLC systems.

Fluoride induced testicular toxicities in adult Wistar rats

Fluoride is essential for the development of teeth and bone but its excessive exposure causes reprotoxic effects. We have studied the graded effects of different doses of sodium fluoride (NaF) on 24 adult Wistar rats which were randomly divided into four groups (n = 6). All the rats were given normal diet prepared in our laboratory. Control (group I) rats were received vehicle only and treated rats (group II, III, and IV) were administered NaF orally at 10, 15, and 20 mg/kg/d doses, respectively, for 30 consecutive days. Gravimetric index of testis was decreased significantly in group III and IV rats but such changes were not observed in the accessory reproductive organs. Marked alterations in number, motility, viability, and plasma membrane functional integrity of caudal spermatozoa were noted in most of the treated groups. Noticeable alterations in testicular histoarchitecture were observed in group III and IV rats. Graded Changes of testicular redox homeostasis were noted by assessment of enzymatic (superoxide dismutase [SOD], catalase, glutathione s-transferase [GST], and glutathione peroxidase [GPx]) and nonenzymatic (malondialdehyde [MDA] and protein carbonyl [PC]) markers. Changes of testicular functional markers (acid phosphatase [ACP], alkaline phosphatase [ALP], and lactate dehydrogenase (LDH) activity) were noted in group III and IV rats. DNA fragmentation assay proved the possibility of DNA damage caused by oxidative stress, as evidenced by prominent trailing pattern of fragmented testicular genomic DNA from group III and IV rats. The study concludes that fluoride-mediated oxidative stress not only impedes the structural and functional facets of testis but also results in testicular DNA damage.

A simple joint control pattern dominates performance of unconstrained arm movements of daily living tasks.

A trailing joint control pattern, during which a single joint is rotated actively and the mechanical effect of this motion is used to move the other joints, was previously observed during simplified, laboratory-based tasks. We examined whether this simple pattern also underlies control of complex, unconstrained arm movements of daily activities. Six tasks were analyzed. Using kinematic data, we estimated motion of 7 degrees of freedom (DOF) of the shoulder, elbow, and wrist, and the contribution of muscle and passive interaction and gravitational torques to net torque at each joint. Despite task variety, the hand was transported predominantly by shoulder and elbow flexion/extension, although shoulder external/internal rotation also contributed in some tasks. The other DOF were used to orient the hand in space. The trailing pattern represented by production of net torque by passive torques at the shoulder or elbow or both was observed during the biggest portion of each movement. Net torque generation by muscle torque at both joints simultaneously was mainly limited to movement initiation toward the targets and movement termination when returning to the initial position, and associated with needing to overcome gravity. The results support the interpretation of previous studies that prevalence of the trailing pattern is a feature of skillful, coordinated movements. The simplicity of the trailing pattern is promising for quantification of dyscoordination caused by motor disorders and formulation of straightforward instructions to facilitate rehabilitation and motor learning.

Audit Trail Generator and Pattern Analyzer for Secure Online Transactions in Academic Institutions

Audit Trail Generator and Pattern Analyzer for Secure Online Transactions in Academic Institutions

Optimal random search using limited spatial memory

Lévy walks are known to be efficient movements because Lévy walkers search wide areas while restricting returns to previously visited sites. A self-avoiding walk (SAW) is a series of moves on a lattice that visit the same place only once. As such, SAWs can also be effective search algorithms. However, it is not realistic that foragers memorize many visited positions for a long time. In this work, we investigated whether foragers performed optimal searches when having limited memory. The agent in our model followed SAWs to some extent by memorizing and avoiding visited places. However, the agent lost its memory after a while. In that situation, the agent changed its reactions to visited patches by considering global trail patterns based on local memorized information. As a result, we succeeded in making the agent occasionally produce ballistic walks related to power-law tailed movements across some ranges.

Micro-Patterned Surfaces That Exploit Stigmergy to Inhibit Biofilm Expansion.

Twitching motility is a mode of surface translocation that is mediated by the extension and retraction of type IV pili and which, depending on the conditions, enables migration of individual cells or can manifest as a complex multicellular collective behavior that leads to biofilm expansion. When twitching motility occurs at the interface of an abiotic surface and solidified nutrient media, it can lead to the emergence of extensive self-organized patterns of interconnected trails that form as a consequence of the actively migrating bacteria forging a furrow network in the substratum beneath the expanding biofilm. These furrows appear to direct bacterial movements much in the same way that roads and footpaths coordinate motor vehicle and human pedestrian traffic. Self-organizing systems such as these can be accounted for by the concept of stigmergy which describes self-organization that emerges through indirect communication via persistent signals within the environment. Many bacterial communities are able to actively migrate across solid and semi-solid surfaces through complex multicellular collective behaviors such as twitching motility and flagella-mediated swarming motility. Here, we have examined the potential of exploiting the stigmergic behavior of furrow-mediated trail following as a means of controlling bacterial biofilm expansion along abiotic surfaces. We found that incorporation of a series of parallel micro-fabricated furrows significantly impeded active biofilm expansion by Pseudomonas aeruginosa and Proteus vulgaris. We observed that in both cases bacterial movements tended to be directed along the furrows. We also observed that narrow furrows were most effective at disrupting biofilm expansion as they impeded the ability of cells to self-organize into multicellular assemblies required for escape from the furrows and migration into new territory. Our results suggest that the implementation of micro-fabricated furrows that exploit stigmergy may be a novel approach to impeding active biofilm expansion across abiotic surfaces such as those used in medical and industrial settings.

A New Skid Trail Pattern Design for Farm Tractors Using Linear Programing and Geographical Information Systems

Farm tractor skidding is one of the common methods of timber extraction in Turkey. However, the absence of an optimal skidding plan covering the entire production area can result in time loss and negative environmental impacts. In this study, the timber extraction by farm tractors was analyzed, and a new skid trail pattern design was developed using Linear Programming (LP) and Geographical Information Systems (GIS). First, a sample skidding operation was evaluated with a time study, and an optimum skidding model was generated with LP. Then, the new skidding pattern was developed by an optimum skidding model and GIS analysis. At the end of the study, the developed new skid trail pattern was implemented in the study area and tested by running a time study. Using the newly developed “Direct Skid Trail Pattern (DSTP)” model, a 16.84% increase in working time performance was observed when the products were extracted by farm tractors compared to the existing practices. On the other hand, the average soil compaction value measured in the study area at depths of 0–5 cm and 5–10 cm was found to be greater in the sample area skid trails than in the control points. The average density of the skid trails was 281 m/ha, while it decreased to 187 m/ha by using the developed pattern. It was also found that 44,829 ton/ha of soil losses were prevented by using the DSTP model; therefore, environmental damages were decreased.

Neural control of arm movements reveals a tendency to use gravity to simplify joint coordination rather than to decrease muscle effort

How gravity influences neural control of arm movements remains under debate. We tested three alternative interpretations suggested by previous research: (1) that muscular control includes two components, tonic which compensates for gravity and phasic which produces the movement; (2) that there is a tendency to exploit gravity to reduce muscle effort; and (3) that there is a tendency to use a trailing pattern of joint control during which either the shoulder or elbow is rotated actively and the other joint rotates predominantly passively, and to exploit gravity for control of the passively rotated joint. A free-stroke drawing task was performed that required production of center-out strokes within a circle while selecting stroke directions randomly. The circle was positioned in the horizontal, sagittal, and frontal plane. The arm joints freely rotated in space. In each plane, the distribution of the strokes across directions was non-uniform. Directional histograms were built and their peaks were used to identify preferred movement directions. The directional preferences were especially pronounced in the two vertical planes. The upward directions were most preferred. To test the three interpretations, we used a kinetic analysis that determined the role of gravitational torque in the production of movement in the preferred directions. The results supported the third interpretation and provided evidence against the first and second interpretation. The trailing pattern has been associated with reduced neural effort for joint coordination, and therefore, we conclude that the major tendency with respect to gravity is to exploit it for simplification of joint coordination.

Enhancement of Chemotactic Cell Aggregation by Haptotactic Cell-To-Cell Interaction.

The crawling of biological cell is a complex phenomenon involving various biochemical and mechanical processes. Some of these processes are intrinsic to individual cells, while others pertain to cell-to-cell interactions and to their responses to extrinsically imposed cues. Here, we report an interesting aggregation dynamics of mathematical model cells, when they perform chemotaxis in response to an externally imposed global chemical gradient while they influence each other through a haptotaxis-mediated social interaction, which confers intriguing trail patterns. In the absence of the cell-to-cell interaction, the equilibrium population density profile fits well to that of a simple Keller-Segal population dynamic model, in which a chemotactic current density competes with a normal diffusive current density , where p and ρ refer to the concentration of chemoattractant and population density, respectively. We find that the cell-to-cell interaction confers a far more compact aggregation resulting in a much higher peak equilibrium cell density. The mathematical model system is applicable to many biological systems such as swarming microglia and neutrophils or accumulating ants towards a localized food source.

Strategy of arm movement control is determined by minimization of neural effort for joint coordination.

Optimality criteria underlying organization of arm movements are often validated by testing their ability to adequately predict hand trajectories. However, kinematic redundancy of the arm allows production of the same hand trajectory through different joint coordination patterns. We therefore consider movement optimality at the level of joint coordination patterns. A review of studies of multi-joint movement control suggests that a 'trailing' pattern of joint control is consistently observed during which a single ('leading') joint is rotated actively and interaction torque produced by this joint is the primary contributor to the motion of the other ('trailing') joints. A tendency to use the trailing pattern whenever the kinematic redundancy is sufficient and increased utilization of this pattern during skillful movements suggests optimality of the trailing pattern. The goal of this study is to determine the cost function minimization of which predicts the trailing pattern. We show that extensive experimental testing of many known cost functions cannot successfully explain optimality of the trailing pattern. We therefore propose a novel cost function that represents neural effort for joint coordination. That effort is quantified as the cost of neural information processing required for joint coordination. We show that a tendency to reduce this 'neurocomputational' cost predicts the trailing pattern and that the theoretically developed predictions fully agree with the experimental findings on control of multi-joint movements. Implications for future research of the suggested interpretation of the trailing joint control pattern and the theory of joint coordination underlying it are discussed.

Influence of workspace constraints on directional preferences of 3D arm movements.

We previously demonstrated a tendency to perform arm movements by using a trailing joint control pattern during which either the shoulder or elbow is rotated actively and the other (trailing) joint is rotated predominantly passively, by interaction torque during horizontal movements and by interaction and gravitational torque during 3D arm movements. This tendency was established with a free-stroke drawing task that required production of series of strokes in randomly selected directions from the center to the perimeter of a horizontal circle. The studies demonstrated that within a planar workspace, the usage of the trailing pattern depends on movement direction and the most frequently selected directions are those providing the opportunity to use the trailing pattern. Here, we studied whether the opportunity to use the preferred trailing pattern also depends on the orientation of the planar workspace. The free-stroke drawing task was performed with unconstrained arm movements within circles of a left-diagonal (LD) and right-diagonal (RD) orientation. Two pronounced preferred directions were revealed in the LD condition, and they were the directions in which the trailing pattern was used. Directional preferences were less pronounced, and the trailing pattern was not observed in any directions in the RD condition. Also, subjects identified the RD condition as inconvenient. The results reinforce the previous finding of the propensity to use the trailing pattern during arm movements. They also suggest that orientations of the workspaces in manual activities should be designed to support the trailing pattern as a favored type of joint control.

Branching angles reflect a trade-off between reducing trail maintenance costs or travel distances in leaf-cutting ants.

The design of transport paths in consuming entities that use routes to access food should be under strong selective pressures to reduce costs and increase benefits. We studied the adaptive nature of branching angles in foraging trail networks of the two most abundant tropical leaf-cutting ant species. We mathematically assessed how these angles should reflect the relative weight of the pressure for reducing either trail maintenance effort or traveling distances. Bifurcation angles of ant foraging trails strongly differed depending on the location of the nests. Ant colonies in open areas showed more acute branching angles, which best shorten travel distances but create longer new trail sections to maintain than a perpendicular branch, suggesting that trail maintenance costs are smaller compared to the benefit of reduced traveling distance. Conversely, ant colonies in forest showed less acute branching angles, indicating that maintenance costs are of larger importance relative to the benefits of shortening travel distances. The trail pattern evident in forests may be attributable to huge amounts of litterfall that .increase trail maintenance costs, and the abundant canopy cover that reduces traveling costs by mitigating direct sunlight and rain. These results suggest that branching angles represent a trade-off between reducing maintenance work and shortening travel distances, illustrating how animal constructions can adjust to diverse environmental conditions. This idea may help to understand diverse networks systems, including urban travel networks.

High-resolution X-ray computed microtomography: A holistic approach to metamorphic fabric analyses

An intrinsic limitation of studying microstructures in thin section is that their spatial (three-dimensional, 3-D) distribution, shape, and orientation have to be inferred by combining 2-D data from different sections. This procedure always involves some degree of interpretation that in some cases can be ambiguous. Recent advances in high-resolution X-ray computed microtomography have made possible the direct imaging in 3-D of volumes of rock to centimeter scale. This rapidly evolving technology is nondestructive and provides a holistic approach of microstructural analysis that eliminates interpretative procedures associated with 2-D methods. Spatial images can be generated through any part of the rock sample and used as virtual petrographic sections. Our application of this technique to an oriented drill core sample from the classic Orijarvi metamorphic region of southern Finland reveals a number of in situ 3-D aspects, including: (1) the spatial distribution and shape of andalusite porphyroblasts, (2) the geometry of a matrix foliation anastomosing around the porphyroblasts, (3) a millimeter-scale compositional layering that controlled the oscillation of porphyroblasts and sulfide mineralization, and (4) distinct inclusion trail patterns characterizing porphyroblast core versus rim zones. The combined data indicate that the steeply dipping bedding-subparallel foliation that characterizes the Orijarvi area formed by bulk north-south crustal shortening and associated vertical stretching.

Trails across the heterogeneous information environment

Purpose – The purpose of this paper is to aim at modelling the trails, which are search patterns with several search systems across the heterogeneous information environment. In addition, the author seeks to examine what kinds of trails occur in routine, semi-complex and complex tasks, and what barrier types occur during the trail-blazing. Design/methodology/approach – The author used qualitative task-based approach with shadowing of six molecular medicine researchers during six months, and collected their web interaction logs. Data triangulation made this kind of detailed search system integration analysis possible. Findings – Five trail patterns emerged: branches, chains, lists, singles and berrypicking trails. The berrypicking was typical to complex work tasks, whereas the branches were common in routine work tasks. Singles and lists were employed typically in semi-complex tasks. In all kinds of trails, the barriers occurred often during the interaction with a single system, but there was a considerable number of barriers with the malfunctioning system integration, and lacking integration features. The findings propose that the trails could be used to reduce the amount of laborious manual system integration, and that there is a need for support to explorative search process in berrypicking trails. Originality/value – Research of information behaviour yielding to different types of search patters with several search systems during real-world work task performance in molecular medicine have not been published previously. The author presents a task-based approach how to model search behaviour patterns. The author discusses the issue of system integration, which is a great challenge in biomedical domain, from the viewpoints of information studies and search behaviour.

Self-organization of bacterial biofilms is facilitated by extracellular DNA

Twitching motility-mediated biofilm expansion is a complex, multicellular behavior that enables the active colonization of surfaces by many species of bacteria. In this study we have explored the emergence of intricate network patterns of interconnected trails that form in actively expanding biofilms of Pseudomonas aeruginosa. We have used high-resolution, phase-contrast time-lapse microscopy and developed sophisticated computer vision algorithms to track and analyze individual cell movements during expansion of P. aeruginosa biofilms. We have also used atomic force microscopy to examine the topography of the substrate underneath the expanding biofilm. Our analyses reveal that at the leading edge of the biofilm, highly coherent groups of bacteria migrate across the surface of the semisolid media and in doing so create furrows along which following cells preferentially migrate. This leads to the emergence of a network of trails that guide mass transit toward the leading edges of the biofilm. We have also determined that extracellular DNA (eDNA) facilitates efficient traffic flow throughout the furrow network by maintaining coherent cell alignments, thereby avoiding traffic jams and ensuring an efficient supply of cells to the migrating front. Our analyses reveal that eDNA also coordinates the movements of cells in the leading edge vanguard rafts and is required for the assembly of cells into the "bulldozer" aggregates that forge the interconnecting furrows. Our observations have revealed that large-scale self-organization of cells in actively expanding biofilms of P. aeruginosa occurs through construction of an intricate network of furrows that is facilitated by eDNA.

Motion Simulation of Dual-Frequency Vibrating Screen

In order to reduce screen plugging and screen pasting, improve the efficiency of screening, a kind of dual-frequency vibrating screen was introduced. It had been used three exciting motors. We established the mechanical model of this vibrating screen, and used Matlab-simulink software to analyze the trajectory changes of screen surface, influenced by mass moment rate, initial phase differences and installation position between high and low frequency exciting motors. The results of the study indicate that, the rate of mass moment and difference of initial phase angle have great influence on the motion trail pattern and amplitude of vibration of the screen, and the installation position of high-frequency exciting motor have less influence on screen surface trajectory under the condition of exciting motors’ parameters given in this article. When designing dual-frequency vibrating screen, we can use the method of this paper to select appropriate rate of mass moment, difference of initial phase angle and so on, and achieve the expected motion trajectory of vibrating screen.