Tracking Duration Research Articles

3-Dimensional Tracking of Non-blinking 'Giant' Quantum Dots in Live Cells.

While semiconductor quantum dots (QDs) have been used successfully in numerous single particle tracking (SPT) studies due to their high photoluminescence efficiency, photostability, and broad palette of emission colors, conventional QDs exhibit fluorescence intermittency or 'blinking,' which causes ambiguity in particle trajectory analysis and limits tracking duration. Here, non-blinking 'giant' quantum dots (gQDs) are exploited to study IgE-FcεRI receptor dynamics in live cells using a confocal-based 3D SPT microscope. There is a 7-fold increase in the probability of observing IgE-FcεRI for longer than 1 min using the gQDs compared to commercially available QDs. A time-gated photon-pair correlation analysis is implemented to verify that selected SPT trajectories are definitively from individual gQDs and not aggregates. The increase in tracking duration for the gQDs allows the observation of multiple changes in diffusion rates of individual IgE-FcεRI receptors occurring on long (>1 min) time scales, which are quantified using a time-dependent diffusion coefficient and hidden Markov modeling. Non-blinking gQDs should become an important tool in future live cell 2D and 3D SPT studies, especially in cases where changes in cellular dynamics are occurring on the time scale of several minutes.

3 Dimensional Tracking of Blinking Suppressed Quantum Dots in Live Cells

While quantum dots (QDs) have been used successfully in numerous single particle tracking (SPT) studies due to their high photoluminescence, photostability, and tunable wavelength emission, QDs often undergo fluorescence intermittency through time known as blinking which causes ambiguity in particle trajectory analysis and limits the tracking duration. Here, we implement blinking-suppressed giant quantum dots (gQDs) to study IgE-FcεRI receptor dynamics in live cells using a confocal-based 3-dimensional (3D) SPT microscope.

Distribution and movement of juvenile and sub-adult Chinese sturgeon (Acipenser sinensis Gray, 1835) in the Three Gorges Reservoir and the adjacent upstream free-flowing Yangtze River section: a re-introduction trial

Summary The aim of this 2008–2012 study was to prove the hypothesis that the Three Gorges Reservoir (TGR) and the upper freeflowing section can offer a habitat for restocking the Chinese sturgeon, Acipenser sinensis. Thus, 498 cultured A. sinensis (including 28 sub-adults tagged with ultrasonic transmitters) were released into the TGR and the adjacent free-flowing section of the Yangtze River. The distribution, movement and growth of the released fish were collected by acoustic telemetry and bycatch information. Results indicated that only three sub-adults migrated upstream to the free-flowing section where they remained for the three-year observation (limited by the longevity of the transmitter battery). However, most subadults migrated downstream after release, with a migration distance of 15–877 km as well as a tracking duration from 19 to 6063 h. The downstream traveling speed in the free-flowing section (mean = 3.70 km h 1 , range = 1.51–8.25 km h 1 ) was significantly faster than that in the reservoir section (mean = 1.05 km h 1 , range = 0.12–1.82 km h 1 ;p < 0.05). Only three sub-adults migrated to within 3 km of Three Gorges Dam (TGD) and stayed in the reservoir. Sub-adults stayed obviously deeper within the reservoir (mean = 11.47 m) than in the free-flowing section (mean = 3.63 m; p < 0.05). Juveniles were recaptured from 45–810 km downstream their release sites with a mean traveling speed of 1.05 km h 1 (range = 0.13–1.82 km h 1 ), lower than that of the sub-adults released in the free-flowing section. Twelve percent of juveniles released in one of the tributaries of the Yangtze River found the entrance and migrated downstream to the reservoir within the first 30 days. Average body weight of the recaptured juveniles increased by 10.3% (range = 2.3%–15.3%) and some crustaceans (e.g. river shrimp) were found in the stomach and gut of two juveniles. The results demonstrate that the TGR and its adjacent upstream free-flowing Yangtze River section can serve as reintroduction sites to support a certain quantity of Chinese sturgeon to remain and mature there.

High-use areas, seasonal movements and dive patterns of juvenile loggerhead sea turtles in the Southwestern Atlantic Ocean

Characterizing the behaviors of sea turtles and identifying high-use areas as they vary in time and space is important for conservation planning, particularly when turtles overlap with fisheries that may unintentionally harm them. Between July 2006 and March 2010, 27 satel- lite transmitters were deployed at sea on juvenile loggerheads Caretta caretta captured as bycatch in the Uruguayan and Brazilian pelagic longline fisheries operating in the Southwestern Atlantic Ocean. Tracking duration ranged from 3 to 639 d (mean ± SD: 259 ± 159 d; n = 27), during which turtles moved between latitudes of 25 to 45° S and longitudes 35 to 54° W. High-use areas for the tracked turtles were over the continental shelf and slope within the Uruguayan, Argentin- ian, and Brazilian exclusive economic zones and in adjacent international waters. Diving informa- tion was available for 5 turtles. The maximum dive depth recorded varied between 100 and 300 m. Two turtles demonstrated potential bottom-feeding behaviors by diving to depths that corre- sponded closely with the depth of the seafloor (<200 m) at their given location. The sea surface temperature encountered by tagged turtles was on average 19.8 ± 2.3°C (range: 10.2 to 28.4°C), and turtles showed an affinity for waters supporting moderate to high primary productivity levels (0.43 ± 0.89 mg m �3 chlorophyll a). Latitudinal movements varied by season and sea surface tem- perature. These findings, along with those of other studies conducted in the region, demonstrate the need to strengthen ongoing collaborative efforts between neighboring countries and other international partnerships to further the research and management of sea turtles in this area.

Off to a bad start: Uncertainty about the number of targets at the onset of multiple object tracking.

Visual tracking abilities are limited to only a few objects at a time. When do errors arise? We hypothesized that some errors arise prior to tracking; specifically, during the first moments of a trial because of an inability to correctly perceive the number of targets in a display. To test this hypothesis, we modified a basic multiple object tracking (MOT) task in two ways: (1) we distilled the first moments of MOT into a static working memory task, requiring participants to remember and then identify targets among nontargets in displays without motion; (2) we unconstrained the number of responses a participant could make, asking them to terminate each trial when they felt that they had made an adequate number of responses. In Experiment 1, participants made the wrong number of responses in a considerable number of trials, and they tendered the wrong number of responses more frequently with larger loads. Comparisons across different delay durations demonstrated that these results were not caused by temporal decay. Follow-up experiments produced similar results when participants stated the cardinal number of targets perceived in a static trial (Experiment 2), and when they reported whether or not a test display included the same number of targets as a memory display (Experiment 3). Finally, with a typical tracking duration, participants also produced the wrong number of responses frequently (Experiment 4). Thus, some of the difficulty associated with MOT originates from uncertainty about the number of targets at the start of an episode.

Spatial behaviour and survival of translocated wild brown hares

The fragility of many populations of brown hares in Western Europe is a concern for managers, hunters and naturalists. We took advantage of a locally high density population to use wild individuals to restock areas where the species had disappeared or was close to disappearing. The aim of the project was to assess the evolution of the spatial behaviour after release using radio–tracking. Over 150 wild brown hares were translocated, one third of which were fitted with radio collars. In addition, fifteen individuals were radio–tagged and released back into the source population as a control. Most individuals settled in less than two months and their seasonal home range, once settled, was similar to that observed in the source population. Mean duration of tracking was not significantly different between the two groups. Moreover, two years after the last translocation, tagged individuals can still be observed, but most hares present are not tagged, which indicates natural reproduction of the released individuals. The translocation of wild individuals thus appears to give encouraging results.

Behavioral dynamics and neural grounding of a dynamic field theory of multi-object tracking.

The ability to dynamically track moving objects in the environment is crucial for efficient interaction with the local surrounds. Here, we examined this ability in the context of the multi-object tracking (MOT) task. Several theories have been proposed to explain how people track moving objects; however, only one of these previous theories is implemented in a real-time process model, and there has been no direct contact between theories of object tracking and the growing neural literature using ERPs and fMRI. Here, we present a neural process model of object tracking that builds from a Dynamic Field Theory of spatial cognition. Simulations reveal that our dynamic field model captures recent behavioral data examining the impact of speed and tracking duration on MOT performance. Moreover, we show that the same model with the same trajectories and parameters can shed light on recent ERP results probing how people distribute attentional resources to targets vs. distractors. We conclude by comparing this new theory of object tracking to other recent accounts, and discuss how the neural grounding of the theory might be effectively explored in future work.

Estimation of Female Home-range Size During the Nestling Period of Dark-eyed Juncos

Studies of spatial activity of songbirds during the nesting cycle have largely focused on male activity and neglected female space use, particularly outside the fertile period. We estimated the home-range size of seven female Dark-eyed Juncos (Junco hyemalis) 3 days after their nestlings had hatched. We used radiotelemetry to track female movements for 2 hrs on the afternoon of day 3 of nestling life, and 2 hrs on both the morning and afternoon of days 4 and 5. Female location and behavior were recorded every 10 min for the duration of tracking. Females exhibited a mean home-range size of 0.833 ha (range = 0.156–2.450 ha). Our estimate of home-range size during the nestling period was significantly smaller than a previous estimate of female home-range size during the fertile period in the same junco population. Home-range size varied greatly between individuals, and the observed differences may be attributable to variation in resource availability.

Satellite Tracking of Manta Rays Highlights Challenges to Their Conservation

We describe the real-time movements of the last of the marine mega-vertebrate taxa to be satellite tracked – the giant manta ray (or devil fish, Manta birostris), the world's largest ray at over 6 m disc width. Almost nothing is known about manta ray movements and their environmental preferences, making them one of the least understood of the marine mega-vertebrates. Red listed by the International Union for the Conservation of Nature as ‘Vulnerable’ to extinction, manta rays are known to be subject to direct and incidental capture and some populations are declining. Satellite-tracked manta rays associated with seasonal upwelling events and thermal fronts off the Yucatan peninsula, Mexico, and made short-range shuttling movements, foraging along and between them. The majority of locations were received from waters shallower than 50 m deep, representing thermally dynamic and productive waters. Manta rays remained in the Mexican Exclusive Economic Zone for the duration of tracking but only 12% of tracking locations were received from within Marine Protected Areas (MPAs). Our results on the spatio-temporal distribution of these enigmatic rays highlight opportunities and challenges to management efforts.

Reallocating attention during multiple object tracking

Wolfe, Place, and Horowitz (Psychonomic Bulletin & Review 14:344-349, 2007) found that participants were relatively unaffected by selecting and deselecting targets while performing a multiple object tracking task, such that maintaining tracking was possible for longer durations than the few seconds typically studied. Though this result was generally consistent with other findings on tracking duration (Franconeri, Jonathon, & Scimeca Psychological Science 21:920-925, 2010), it was inconsistent with research involving cuing paradigms, specifically precues (Pylyshyn & Annan Spatial Vision 19:485-504, 2006). In the present research, we broke down the addition and removal of targets into separate conditions and incorporated a simple performance model to evaluate the costs associated with the selection and deselection of moving targets. Across three experiments, we demonstrated evidence against a cost being associated with any shift in attention, but rather that varying the type of cue used for target deselection produces no additional cost to performance and that hysteresis effects are not induced by a reduction in tracking load.

GPS cell phone tracking in the Greater Tokyo Area: A field test on raccoon dogs

We tested instantaneous GPS cell phone telemetry to record movement data of raccoon dogs (Nyctereutes procyonoides) in Abiko city, Greater Tokyo, Japan. We monitored the changes in locations of six raccoon dogs in various land use types such as roads, golf courses, towns, rice and crop paddies, and forest. Data were downloaded instantaneously using cell phone networks and the internet, remotely to a desktop computer. We obtained 410 location points and the maximum duration of individual tracking was 144 hours. The success rate of GPS positioning varied among individuals. On average, the success rate of three raccoon dogs in a relatively open area was 98% and that of three raccoon dogs in a mosaic area was 70%. In total, 372 of the data points (91 % of all downloaded data) with reliable accuracy were used to analyze movement speed during the day time as well as habitat use of the raccoon dogs, revealing various spatial and temporal behavioral patterns. Human activities were the likely cause of characteristic behaviors in tall weed patches and golf courses, and daily patterns of movement. Our results indicate the potential utility of GPS cell phone tracking to efficiently monitor and manage wildlife in changing urban environments.

Geographic distribution of the mid‐continent population of sandhill cranes and related management applications

AbstractThe Mid‐continent Population (MCP) of sandhill cranes (Grus canadensis) is widely hunted in North America and is separated into the Gulf Coast Subpopulation and Western Subpopulation for management purposes. Effective harvest management of the MCP requires detailed knowledge of breeding distribution of subspecies and subpopulations, chronology of their use of fall staging areas and wintering grounds, and exposure to and harvest from hunting. To address these information needs, we tagged 153 sandhill cranes with Platform Transmitting Terminals (PTTs) during 22 February–12 April 1998–2003 in the Central and North Platte River valleys of south‐central Nebraska. We monitored PTT‐tagged sandhill cranes, hereafter tagged cranes, from their arrival to departure from breeding grounds, during their fall migration, and throughout winter using the Argos satellite tracking system. The tracking effort yielded 74,041 useable locations over 49,350 tag days; median duration of tracking of individual cranes was 352 days and 73 cranes were tracked &gt;12 months. Genetic sequencing of mitochondrial DNA (mtDNA) from blood samples taken from each of our random sample of tagged cranes indicated 64% wereG. c. canadensisand 34% wereGrus canadensis tabida. Tagged cranes during the breeding season settled in northern temperate, subarctic, and arctic North America (U.S. [23%,n = 35], Canada [57%,n = 87]) and arctic regions of northeast Asia (Russia [20%,n = 31]). Distribution of tagged cranes by breeding affiliation was as follows: Western Alaska–Siberia (WA–S, 42 ± 4% [SE]), northern Canada–Nunavut (NC–N, 21 ± 4%), west‐central Canada–Alaska (WC–A, 23 ± 4%) and East‐central Canada–Minnesota (EC–M, 14 ± 3%). All tagged cranes returned to the same breeding affiliation used during the previous year with a median distance of 1.60 km (range: 0.08–7.7 km,n = 53) separating sites used in year 1 and year 2. Fall staging occurred primarily in central and western Saskatchewan (69%), North Dakota (16%), southwestern Manitoba (10%), and northwestern Minnesota (3%). Space‐use sharing indices showed that except for NC–N and WC–A birds, probability of finding a crane from one breeding affiliation within the home range of another breeding affiliation was low during fall staging. Tagged cranes from WC–A and EC–M breeding affiliations, on average, spent 25 and 20 days, respectively, longer on fall staging areas in the northern plains than did WA–S and NC–N birds. Cranes in the NC–N, WA–S, and WC–A affiliations spent 99%, 74%, and 64%, respectively, of winter in western Texas in Hunting Zone A; EC–M cranes spent 83% of winter along the Texas Gulf Coast in Hunting Zone C. Tagged cranes that settled within the breeding range of the Gulf Coast Subpopulation spent 28% and 42% of fall staging and winter within the range of the Western Subpopulation, indicating sufficient exchange of birds to potentially limit effectiveness of MCP harvest management. Harvests of EC–M and WC–A cranes during 1998–2003 were disproportionately high to their estimated numbers in the MCP, suggesting more conservative harvest strategies may be required for these subpopulations in the future, and for sandhill cranes to occupy major parts of their historical breeding range in the Prairie Pothole Region. Exceptionally high philopatry of MCP cranes of all 4 subpopulations to breeding sites coupled with strong linkages between crane breeding distribution, and fall staging areas and wintering grounds, provide managers guidance for targeting MCP crane harvest to meet management goals. Sufficient temporal or spatial separation exists among the 4 subpopulations on fall staging areas and wintering grounds to allow harvest to be targeted at the subpopulation level in all states and provinces (and most hunting zones within states and provinces) when conditions warrant. Knowledge gained from our study provides decision‐makers in the United States, Canada, Mexico, and Russia with improved guidance for developing sound harvest regulations, focusing conservation efforts, and generating collaborative efforts among these nations on sandhill crane research and management to meet mutually important goals. © 2011 The Wildlife Society.

Movements and post-release mortality of juvenile sea turtles released from gillnets in the lower Cape Fear River, North Carolina, USA

North Carolina coastal waters are an important seasonal foraging habitat for juvenile green Chelonia mydas and Kemp's ridley Lepidochelys kempii sea turtles. Sea turtle mortality due to incidental capture in gillnets is a topic of great concern in this region, and fisheries regulations have been implemented to minimize sea turtle bycatch. Current regulations are based on estimates of fisheries-related sea turtle mortality derived from analyses of fishing effort, observed bycatch, and strandings data. Information regarding the health status of sea turtles at the time of release and doc- umentation of post-release mortality are necessary in order to refine the mortality estimates used to govern management decisions. The primary goals of the present study were to use satellite teleme- try to monitor post-release movements of sea turtles released from gillnets, document post-release mortality, and evaluate the feasibility and reliability of using blood biochemistry data collected at the time of capture to predict post-release mortality. Satellite telemeters were deployed on, and blood samples were collected from, juvenile green and Kemp's ridley sea turtles released from a 14 cm mesh gillnet set in shallow waters (1 to 5 m deep) in the lower Cape Fear River, North Carolina, USA. Twelve of 14 turtles released from the gillnet stayed in the lower Cape Fear River throughout the post-release tracking duration. We documented 1 confirmed and 3 suspected post-release mortali- ties. Blood chemistry analyses revealed differences in plasma ion (K + , Cl - , Na + ) and lactate levels between the turtle that died (confirmed mortality) and all other study animals, suggesting that these variables could serve as chemical predictors of post-release mortality.

Winter habitat use of harbour seals (&lt;i&gt;Phoca vitulina&lt;/i&gt;) fitted with Fastloc™GPS/GSM tags in two tidal bays in France

Winter movements and habitat use of harbour seals (Phoca vitulina) were investigated in two tidal bays in France, at the southern limit of their species range in the Northeast Atlantic. We fitted 15 seals with Fastloc™GPS/GSMtags in the Baie du Mont-Saint-Michel (BMSM) and the Baie des Veys (BDV). Tags relayed 20.6±7.1 GPS locations per seal-day, 81% of all dives performed by the seals and 87% of haulouts, during an average tracking duration of 108±56 days. One seal travelled 380 km away from the BMSM but the other seals remained stationary, with 95% and 55% of at-sea locations ≤ 5 km from the haulout sites in BMSM and BDV respectively. Home range sizes were 137 and 161 km² in BMSM and BDV, and core areas’ sizes, 35 and 22 km² respectively. The seals remained very coastally in both sites with 93% and 71% of at-sea locations located in the intertidal zone of BMSM and BDV respectively. Accordingly, dives were shallow with 63% and 61% of dive maximum depths &lt;4 m and 94% and 88% &lt;10 m (in BMSM and BDV respectively). Preferred foraging areas were located in tidal channels in BMSM, sometimes in the vicinity of rocks or mussel farms. In BDV one seal made foraging trips 10-15 km offshore but all other seals repeatedly used coastal areas, often foraging around mussel farms, shipwrecks or intertidal rocks in tidal currents. We suggest that the importance of the tides combined with local features of the topography allow seals to predict prey availability, driving their foraging strategies towards a number of specific coastal areas. These results further illustrate the behavioural plasticity of the species according to habitat and environmental conditions. Fastloc™ GPS/GSM telemetry is particularly well adapted for the study of seals’ habitat use at a fine geographical and temporal scale, as long as they occasionally come close to shore within GSM coverage.

Performance of GPS Collars Deployed on Free-Ranging Sika Deer in Eastern Hokkaido, Japan

We evaluated the performance of global positioning system (GPS) collars deployed on free-ranging sika deer (Cervus nippon) to study their seasonal migration. We placed 21 GPS collars on 20 individual deer in the Shiranuka Hills, eastern Hokkaido, between March 2002 and March 2004. We could recover 17 (81.0%) collars and retrieved 20,278 location data from 13 collars on 12 individuals during 2002 and 2005. Tracking duration averaged 267 ± 17 (SE) days, fix success rate averaged 62.9% and ranged 34.4–81.8%. The proportion of 3-dimensional location averaged 46.4% and ranged 12.8–99.0%). We evaluated the fix success rates of three seasons (winter, migration period, and summer). In most cases, we found that the fix success rate in winter was significantly higher than that in summer. We consider the canopy cover of habitat affects the fix success rate of GPS collar. Although the GPS-based telemetry has some risks related to collar recovery and data retrieval, this method provides us a large volume of location data and is a suitable method for studying migratory behavior of sika deer.

Burrow Use and Survival of Newly Metamorphosed Gopher Frogs (Rana capito)

The transition from aquatic to terrestrial habitat is thought to be a period of high mortality for amphibians. We used radio telemetry to estimate survival and study factors influencing survivorship of newly metamorphosed Gopher Frogs (Rana capito). Predation was very high and only 12.5% of frogs survived their first month in the terrestrial habitat. All documented predation occurred during the frogs' initial 12 days in the uplands, and snakes (Coluber constrictor and Thamnophis sirtalis) were the major predators. Also, frogs were preyed upon by mammals and birds and killed by vehicles along dirt roads. Survival rates varied among ponds, with the survival rate at one pond being significantly lower than survival rates at three other ponds. Survival of frogs was dependent on their use of underground refuges, particularly burrows excavated by Gopher Tortoises (Gopherus polyphemus) and small mammals. Using underground refuges reduced the risk of mortality to only 4% of that faced by frogs while in the open environment; in fact, all surviving frogs located a burrow within their initial eight days in the terrestrial habitat and remained there for the duration of tracking. Our results demonstrate the dependence of Gopher Frogs on underground refuges and suggest that the availability of burrows near breeding ponds influences survival of juveniles and, thus, the recruitment of adults.

Numerical simulations of eddies in the Gulf of Lion

We present realistic simulations of mesoscale anticyclonic eddies, present in the western side of the Gulf of Lion and generally observed in satellite imagery during July and August. A nested model of 1-km resolution covering the Gulf of Lion is implemented from a coarse model of 3-km resolution. The models use an upwind-type advection–diffusion scheme, in which the numerical diffusion term is adjusted by an attenuation coefficient. Sensitivity tests have been carried out, varying the model spatial resolution and the attenuation coefficient to reproduce the (sub)mesoscale structures. A wavelet technique is applied to analyze the modelled horizontal relative vorticity in order to define the area, position and tracking duration of the eddy structures. Comparisons between the modelled eddies and those observed by satellite have allowed us to choose the best model setup. With this setup, the studied anticyclonic eddy lasted for 60 days.

Founding Environment Variation, Founding Environment Grain, Niche Width, and Niche Overlap Density: An Analysis of Organization Ecology of Chemical Material Manufacturer in Taiwan

Based on various perspectives of organization ecology, this study probes into dominant influences exercised by: ”founding environment variation”; ”founding environment grain”; ”niche width” and ”niche overlap density”, in regards to the mortality of an organization. To answer the aforementioned, this study adopts 1446 chemical material manufacturers (total tracking duration 46 years, from 1958 to 2004) as analytical samples, and applies the Gompertz regression model to examine the hypothesis. The results show that: (a) higher environment variation and higher environment grain raised more potential for organizational mortality; (b) the larger niche width the manufacturers had, demonstrated more potential for organizational mortality; (c) the broader niche overlap density existed among the manufacturers, the less potential there were for organizational mortality; (d) the strategies of niche width and niche overlap density may change the degree of dominant influence, exercised by founding environment variation and environment grain, relevant to the mortality of an organization. These findings are accompanied with further interviews conducted with experts in order to understand their implications in practice.

Effect of transmitter mass and tracking duration on body mass change of two anuran species

AbstractDuring tracking studies, the behaviour of animals may be affected by the tracking and tagging methods used, which may influence the results obtained. Our aim was to assess the impact of transmitter mass and the duration of tracking period on the body mass change (BMC) of two anuran species that were fitted with externally attached radio transmitters. Bufo b. spinosus and B. viridis were radio-tracked for three months during summer in the active tract of a large gravel-bed river (Tagliamento River, NE Italy). Our results demonstrated that transmitter mass and the duration of the tracking period did not affect BMC of the two anurans in their terrestrial summer habitats because methodological factors poorly predicted variation in BMC. Therefore, we encourage the use of tracking methods in amphibian ecology.

PE 계열 절연재 전기적 특성 평가

This paper describes the results of electrical characteristics assessment for organic insulations of polyethylene(PE) series insulations and acrylonitrile butadiene styrene copolymer(ABS). In the experiment, 4 kinds of specimens by composition density were tested in relative permittivity, specific resistance and tracking duration. A WinDETA system and a tracking test set manufactured for this assessment were used to measure the dielectric parameters and tracking duration, respectively. In measuring the tracking duration, the time from testing voltage application to testing circuit breaking due to the tracking current was measured. As a result, dielectric dispersion was observed in measuring the relative permittivity of ABS. It was confirmed that the relative permittivity decreased with the density of the PE series insulations and it depends rather on the temperature than frequency. In most specimens, specific resistance exponentially decreased with frequency and the result for each specimen was almost similar. By the way, in the tracking test, all the PE series insulations showed more excellent performance than ABS and especially in the case of HDPE, its tracking withstand performance was the best.