Location Of Disturbance Research Articles

Striatal H3K27 Acetylation Linked to Glutamatergic Gene Dysregulation in Human Heroin Abusers Holds Promise as Therapeutic Target

BackgroundOpiate abuse and overdose reached epidemic levels in the United States. However, despite significant advances in animal and in vitro models, little knowledge has been directly accrued regarding the neurobiology of the opiate-addicted human brain. MethodsWe used postmortem human brain specimens from a homogeneous European Caucasian population of heroin users for transcriptional and epigenetic profiling, as well as direct assessment of chromatin accessibility in the striatum, a brain region central to reward and emotion. A rat heroin self-administration model was used to obtain translational molecular and behavioral insights. ResultsOur transcriptome approach revealed marked impairments related to glutamatergic neurotransmission and chromatin remodeling in the human striatum. A series of biochemical experiments tracked the specific location of the epigenetic disturbances to hyperacetylation of lysine 27 of histone H3, showing dynamic correlations with heroin use history and acute opiate toxicology. Targeted investigation of GRIA1, a glutamatergic gene implicated in drug-seeking behavior, verified the increased enrichment of lysine-27 acetylated histone H3 at discrete loci, accompanied by enhanced chromatin accessibility at hyperacetylated regions in the gene body. Analogous epigenetic impairments were detected in the striatum of heroin self-administering rats. Using this translational model, we showed that bromodomain inhibitor JQ1, which blocks the functional readout of acetylated lysines, reduced heroin self-administration and cue-induced drug-seeking behavior. ConclusionsOverall, our data suggest that heroin-related histone H3 hyperacetylation contributes to glutamatergic transcriptional changes that underlie addiction behavior and identify JQ1 as a promising candidate for targeted clinical interventions in heroin use disorder.

SY 15-2 ENDOTHELIAL EPIGENETICS AND ITS ROLE IN MEDIATING BIOMECHANICAL STRESS OF HYPERTENSION

Abstract Hemodynamics creates a constantly changing physical and chemical environment to which the arterial endothelium is exquisitely sensitive. Biomechanical stresses are intrinsic to blood flow characteristics and blood pressure and therefore are important considerations in hypertension. Near branching anatomical sites in arteries, blood flow separates from the main flow to undergo complex multi-directional characteristics for a part of each cardiac cycle (collectively referred to as disturbed flow). Atherosclerosis and aneurysmal pathology develop preferentially at disturbed flow locations, particularly when an additional cardiovascular risk factor such as hypercholesterolemia or high blood pressure are present. In the pre-disease state, a pre-inflammatory endothelial phenotype is characteristically present in such regions in contrast to nearby endothelium outside of the complex disturbed flow fields. A regulatory hierarchy of mechanisms controls endothelial gene and protein expression (and function) in response to the flow environment. Gene expression regulation, the transcription of the DNA (genomic) code to mRNA, is well described by transcription factors, enhancers and repressors, many of which are flow responsive. However, emerging studies describe the additional role of localized disturbed blood flow upon epigenetic mechanisms of endothelial responses to biomechanical stress. Epigenetics and epigenomics (global analyses of epigenetic changes across the entire genome) encompass heritable and non-heritable changes in nuclear chromatin leading to gene expression changes that cannot be attributed to changes in the primary DNA sequence. Hemodynamic stimuli have recently been shown to induce epigenetic responses including transcriptional regulation by proximal promoter DNA methylation, and regulation of gene and protein expression by histone/chromatin remodeling and by noncoding RNA-based mechanisms.Dynamic epigenomic responses to flow that result in regulation of endothelial gene expression in vivo and in vitro include: (i) regions of stable differentially methylated DNA in swine and mouse endothelial genomes that are arterial site-specific and map to atherosusceptibility, (ii) disturbed flow (but not undisturbed flow) applied to endothelial cells in vitro that induces DNA methylation through DNA methyltransferase enrichment of gene promoter regions; the resulting hypermethylation suppresses gene expression, (iii) histone acetylation / deacetylation and methylation that create histone marks that enable or suppress gene expression by controlling access of transcription factors to chromatin DNA, and (iv) short microRNAs and long noncoding RNAs that interact with highly specific binding sites of newly synthesized mRNA to promote its degradation and thus suppress transcription. Flow-mediated epigenomic responses intersect with cis and trans factor regulation to maintain endothelial function in a shear-stressed or pressure-stressed environment and may contribute to localized endothelial dysfunctions that promote localized vascular pathology.The Encyclopedia of DNA Elements (ENCODE) and the International Human Epigenome Consortia (IHEC) have uncovered thousands of putative epigenetic regulatory sites in non-coding regions of the genome. Methylation of cytosine nucleosides in DNA both at/near gene promoter regions as well as at some distance upstream is a potent epigenetic suppressor of transcription. Recently, complete methylated DNA immunoprecipitation sequencing (MeDIP-seq) of regions of arterial endothelium associated with disturbed vs undisturbed flow in vivo in pigs has identified many differentially methylated DNA profiles enriched in exons and 5'UTR sequences of annotated genes, 60 of which are linked to cardiovascular disease. Furthermore, in human arterial endothelial cells in culture we have demonstrated DNA methylation plasticity to be regulated by disturbed flow resulting in suppression (hypermethylation) or stimulation (hypomethylation) of transcription. We propose dynamic DNA methylation to be a genome-wide epigenetic mechanism of transcriptional control that regulates adaptive endothelial phenotype plasticity in response to the local environment, including biomechanical stresses associated with disturbed flow characteristics and hypertension.The epigenomic code therefore has the potential to figure prominently in disease susceptibility and pathogenesis arising from environmental influences independent of, or in concert with, mutations and single nucleotide polymorphisms (SNP) linked to many complex diseases, including hypertension and cardiovascular disease. The role of disturbed flow as a hemodynamic regulator of epigenomic DNA methylation-mediated and histone-mediated gene expression may play a prominent role in endothelial vascular function and dysfunction in hypertension, atherogenesis and aneurysm development. The cellular mechanisms that link hemodynamics and biomechanical stress to the epigenomic code remain unexplored.

Preface: Impacts of extreme climate events and disturbances on carbon dynamics

Abstract. The impacts of extreme climate events and disturbances (ECE&D) on the carbon cycle have received growing attention in recent years. This special issue showcases a collection of recent advances in understanding the impacts of ECE&D on carbon cycling. Notable advances include quantifying how harvesting activities impact forest structure, carbon pool dynamics, and recovery processes; observed drastic increases of the concentrations of dissolved organic carbon and dissolved methane in thermokarst lakes in western Siberia during a summer warming event; disentangling the roles of herbivores and fire on forest carbon dioxide flux; direct and indirect impacts of fire on the global carbon balance; and improved atmospheric inversion of regional carbon sources and sinks by incorporating disturbances. Combined, studies herein indicate several major research needs. First, disturbances and extreme events can interact with one another, and it is important to understand their overall impacts and also disentangle their effects on the carbon cycle. Second, current ecosystem models are not skillful enough to correctly simulate the underlying processes and impacts of ECE&D (e.g., tree mortality and carbon consequences). Third, benchmark data characterizing the timing, location, type, and magnitude of disturbances must be systematically created to improve our ability to quantify carbon dynamics over large areas. Finally, improving the representation of ECE&D in regional climate/earth system models and accounting for the resulting feedbacks to climate are essential for understanding the interactions between climate and ecosystem dynamics.

Optimal Growth in Hypersonic Boundary Layers

The linear form of the parabolized linear stability equations is used in a variational approach to extend the previous body of results for the optimal, nonmodal disturbance growth in boundary-layer flows. This paper investigates the optimal growth characteristics in the hypersonic Mach number regime without any high-enthalpy effects. The influence of wall cooling is studied, with particular emphasis on the role of the initial disturbance location and the value of the spanwise wave number that leads to the maximum energy growth up to a specified location. Unlike previous predictions that used a basic state obtained from a self-similar solution to the boundary-layer equations, mean flow solutions based on the full Navier–Stokes equations are used in select cases to help account for the viscous–inviscid interaction near the leading edge of the plate and for the weak shock wave emanating from that region. Using the full Navier–Stokes mean flow is shown to result in further reduction with Mach number in the magnitude of optimal growth relative to the predictions based on the self-similar approximation to the base flow.

Harmonic disturbance location by applying Bayesian inference

Harmonic pollution is one of the most important power quality issues in electric power systems. Correct location of the main harmonic disturbance source is a key step to solve the problem. This paper presents a method to detect the location of harmonic disturbance source in low voltage network through Bayesian inference. The harmonic state is estimated based on the measurement data from limited measurement points whereby the measurement error is also considered. The performance of the proposed method is assessed through a case study applied in a typical low voltage network. Monte Carlo simulation is used to obtain the statistical results. The influence of different parameters like disturbance level, measurement accuracy level, etc. is discussed. The proposed method shows the adequacy for the analysis of distribution networks.

Local and continental determinants of giant anteater (Myrmecophaga tridactyla) abundance: Biome, human and jaguar roles in population regulation

The giant anteater (Myrmecophaga tridactyla) is currently found in a wide variety of habitats from Honduras to Argentina. Across this wide range, researchers have postulated that anteater populations are negatively affected by several factors, including hunting, habitat loss and fragmentation, fire, vehicle collisions, and predation by jaguars. But no studies to date have evaluated the relative importance of these factors across sites, either at a regional or continental scale. We used camera traps to analyze variation in giant anteater abundance at two spatial scales. At a regional scale, we conducted camera trap surveys in the dry Chaco of Argentina and used occupancy models to explore the effect of protection status and human accessibility on giant anteaters’ relative abundance. At a continental scale, we used data from 40 camera trap studies (representing 42 different locations) and Generalized Linear Models (GLM) to assess the potential relation of biome, human disturbance and the presence of jaguars on giant anteater camera trap records. In the Argentine Chaco, protection and human disturbance do not significantly affect the proportion of area used by the species. The average anteater records/100 camera days and the proportion of sites used are very high across the study area. At a continental scale, anteaters are more frequently recorded in dry forests than in moist forests. Locations with very high human disturbance have camera trap rates that are 5–10 times lower compared to intermediate or low disturbance locations. Finally, giant anteater capture frequency increases up to 70% where jaguars are absent. Dry biomes and intermediate levels of human disturbance may favor anteaters by providing greater habitat heterogeneity coupled with a lower jaguar abundance. This may explain the relatively high abundance of giant anteaters in the Argentine Chaco. However, growing human populations, the advancing agriculture-livestock frontier, and an expanding road network may in time eliminate giant anteaters from most of this region.

Adaptive Online Disturbance Location Considering Anisotropy of Frequency Propagation Speeds

Online disturbance location is of significant importance to wide-area response-based situational awareness, stability analysis and control of the power systems. This paper presents an adaptive online disturbance location method that considers the anisotropy of the frequency propagation speed (FPS). The method geographically partitions the studied power system into several different regions offline. It then extracts the FPS vector for events occurring in each region. The method uses one event simulation for each region. The online simulations take into account changes in the generation, load and power grid topology. The location of the disturbance in each region is estimated specifically based on the speed vector of the region. Parallel computing is used to accelerate the estimation procedure. A part of the North and Central China interconnected power grid, which covers 7 provinces, is selected as an example to verify the effectiveness of the proposed disturbance location method and to analyze the speedup properties of the parallel computing.

能動騒音制御および能動振動制御による二重壁放射音の抑制

This paper presents a new active control method of sound radiated from a double-walled structure. The purpose of this study is to control of sound radiation power level using both of active noise control and active vibration control. First, modal coupling method is introduced which is required to model a vibro-acoustic coupling system. Then, optimal control laws of active noise control and active vibration control for minimizing the sound radiation power are derived in a vector form. Next, some numerical simulations are carried out to demonstrate the validity of the proposed method. As a result of the analysis, reduction of the sound power level is succeeded by feedforward control. Some numerical results show that active noise control is more effective than active vibration control for minimizing the sound power level. In addition, it is shown that by combination of the both control methods, improvement of a control performance is achieved. Furthermore, it is found that control effect rely on the relationship between placement of control sound sources and the disturbance location, while placement of control vibration source does not have significant impact on the control performance.

The Anatomy of a Migraine

Migraine is a pain combined with other symptoms. Does it have an anatomy? Actually no, it does not since combination of symptoms have no anatomy only the cause of migraine does. The locations of the cause of migraines matter because the type of symptom associated with a particular migraine depends greatly on where the underlying brain disturbance location is. Because migraine is a combination of many symptoms, we need to look at different terminology that helps us unravel the cause of migraine and then we can find the anatomy based on the location of the cause.

Ecology of Leonotis nepetifolia l. In Lodna area of Jharia coal field

Leonotis nepetifolia L., a plant of family lamiaceae grows extensively in coal fields and even in stressful conditions like fire area and O.B. dump area. So the present study was designed with the objective is To study the ecology of Leonotis nepetifolia L. growing in different locations like fire area, subsidence area, OB dump area, road side and control area of Lodna coal mines (Jharia coal field) of Dhanbad district, Jharkhand. Present study shows better adaptation of Leonotis nepetifolia in stressful conditions in terms of its morphological characters and biomass. An increase in fresh weight and decrease in dry weight in various disturbed locations clearly indicated that ultimate productivity of plants reduced in adverse conditions of coal mine areas. A high fresh weight of plants in disturbed locations may be because of strategy to overcome the adverse ecological condition by absorbing and accumulating more water. A low BGP may be because of the presence of various toxicological elements and other physical conditions of the soil. An increase in some of the morphometric parameters of Leonotis nepetifolia may be because of stress response of plants which has been reported in various other conditions as well. However possibilities of some evolutionary adaptation of this plant cannot be completely ruled out. A detailed investigation and extensive research work is required to properly infer the results obtained during this study.

A MODIS-based method for detecting large-scale vegetation disturbance due to natural hazards: a case study of Wenchuan earthquake stricken regions in China

In the global carbon cycle, terrestrial biomass plays an important role in both as a sink and source. To evaluate biomass variation due to various natural hazards, it is necessary to detect the location, extent and duration of vegetation disturbance at a large spatial scale with an efficient method. This study contributes to develop such a method, and only the moderate resolution imaging spectroradiometer (MODIS) MOD13Q1 enhanced vegetation index (EVI) products are used to generate a continuous vegetation damage index (CVDI) for detecting severe vegetation disturbance in large areas. To verify the performance of this new index, this study takes the identification of the vegetation damage due to the Wenchuan earthquake in China occurred on 12 May 2008 as a case study. This study calculates the CVDI for the earthquake stricken areas, and delineates the regions with considerable EVI abnormal variation. The study result reveals that those delineated regions with severe vegetation damage are normally consistent with the areas with the landslides caused by the earthquake. Moreover, according to the changes of other vegetation-related MODIS datasets since 12 May 2008, this study discloses that the EVI value in most of the areas, where the vegetation was damaged due to the earthquake, has not reached to the normal value in 2012, which is 4 years after the earthquake. Finally, to validate the vegetation damage areas determined by CVDI method, the high resolution images and field survey information are used. This study confirms that CVDI method can effectively delineate large-scale terrestrial biomass disturbance due to the earthquake and can accurately identify the vegetation recovery process.

Power Quality Disturbance Location Method based on Cross-Feedback - Recursive Least Squares

Due to the randomness and complexity of power quality disturbances, there is lack of mature and reliable detection and analysing methods on power quality disturbance, especially in the construction site with the changeable operation condition .In order to deal with the problems of non-stationary power quality signals and spectrum leakage, a new CF Recursive Least Squares (CF-RLS) based on blind sources separation method is proposed in this paper. Furthermore the way of converging on the proposed method is based on the maximum negative entropy gradient value. In this way, the verges can be detected and the CF-RLS method can meet the requirement of signal reconstruction condition. With the help of Matlab 7.0, the simulation cases with the power system harmonics with single disturbance and mixed disturbance are discussed. Moreover the simulation results show that the harmonics parameters, including amplitudes, phase angles and disturbance time, can be detected precisely. At last, the proposed method can completely meet the requirements of the power quality disturbance location.

An Estimator-Based Distributed Voltage-Predictive Control Strategy for AC Islanded Microgrids

This paper presents an estimator-based voltage-predictive control strategy for ac islanded microgrids, which is able to perform voltage control without any communication facilities. The proposed control strategy is composed of a network voltage estimator and a voltage-predictive controller for each distributed generator, where the voltage estimator serves as an essential tool to obtain network voltages response without using communication links, while the voltage-predictive controller is able to implement offset-free voltage control for a specified bus. The dynamic performance of the proposed voltage control strategy is analyzed through small-signal analysis method, from which the design guideline for the controller parameters is formulated. Furthermore, the robustness of the proposed voltage control strategy is investigated under a series of parameters uncertainties, including the line parameters perturbation, load parameters variation, different disturbance locations, LC filters perturbation, output impedances perturbation, and DG unit fault. The simulation and experimental results show that the proposed control approach is able to perform offset-free voltage control without any communication links and has a good capability to reject uncertain perturbations of islanded microgrids.

Adaptive Tuning of Frequency Thresholds Using Voltage Drop Data in Decentralized Load Shedding

Load shedding (LS) is the last firewall and the most expensive control action against power system blackout. In the conventional under frequency LS (UFLS) schemes, the load drop locations are already determined independently of the event location. Furthermore, the frequency thresholds of LS relays are prespecified and constant values which may not be a comprehensive solution for widespread range of possible events. This paper addresses the decentralized LS in which the instantaneous voltage deviation of load buses is used to determine the frequency thresholds of LS relays. The higher frequency thresholds are assigned to the loads with larger voltage decay which are often located in the vicinity of disturbance location. The proposed method simultaneously benefits from individual UFLS and under voltage LS (UVLS) features which operate in the power system without coordination. Numerical simulations in DigSilent PowerFactory software confirm the efficiency of proposed methodology in the stabilization of the power system after various severe contingencies.

The role of primary cilia in corpus callosum formation is mediated by production of the Gli3 repressor.

Agenesis of the corpus callosum (AgCC) is a frequent brain disorder found in over 80 human congenital syndromes including ciliopathies. Here, we report a severe AgCC in Ftm/Rpgrip1l knockout mouse, which provides a valuable model for Meckel-Grüber syndrome. Rpgrip1l encodes a protein of the ciliary transition zone, which is essential for ciliogenesis in several cell types in mouse including neuroepithelial cells in the developing forebrain. We show that AgCC in Rpgrip1l(-/-) mouse is associated with a disturbed location of guidepost cells in the dorsomedial telencephalon. This mislocalization results from early patterning defects and abnormal cortico-septal boundary (CSB) formation in the medial telencephalon. We demonstrate that all these defects primarily result from altered GLI3 processing. Indeed, AgCC, together with patterning defects and mispositioning of guidepost cells, is rescued by overexpressing in Rpgrip1l(-/-) embryos, the short repressor form of the GLI3 transcription factor (GLI3R), provided by the Gli3(Δ699) allele. Furthermore, Gli3(Δ699) also rescues AgCC in Rfx3(-/-) embryos deficient for the ciliogenic RFX3 transcription factor that regulates the expression of several ciliary genes. These data demonstrate that GLI3 processing is a major outcome of primary cilia function in dorsal telencephalon morphogenesis. Rescuing CC formation in two independent ciliary mutants by GLI3(Δ699) highlights the crucial role of primary cilia in maintaining the proper level of GLI3R required for morphogenesis of the CC.

Single - Point Methods for Location of Electromagnetic Disturbances in Power System

Single - Point Methods for Location of Electromagnetic Disturbances in Power System

Cross-border forest disturbance and the role of natural rubber in mainland Southeast Asia using annual Landsat time series

The recent rise in global demand for natural rubber (Hevea brasiliensis) has led to expansive areas of natural forest being transformed into monoculture plantations. This paper explores the utility of annual Landsat time series for monitoring forest disturbance and the role of natural rubber in mainland Southeast Asia from 2000 to 2012. A region on the Cambodian–Vietnamese border was chosen for this study considering four primary questions: 1) how accurately can annual Landsat time series map the location and timing of forest disturbances in evergreen and seasonal tropical forests, 2) are there cross-border differences in frontier and non-frontier forest disturbance rates between Cambodia and Vietnam, 3) what proportion of disturbances in frontier and non-frontier forests can be accounted for by the impact of rubber plantations, and 4) is there a relationship between global market prices for natural rubber and the annual rate of frontier forest clearing for rubber plantations on both sides of the border. We used LandTrendr (Landsat-based detection of trends in disturbance and recovery) for temporal segmentation of the Landsat time series and disturbance mapping. Our results show that this approach can provide accurate forest disturbance maps but that accuracy is affected by forest type. Highest accuracies were found in evergreen forest (91%), with lower accuracies in mixed (82%) and dry-deciduous forest types (86%). Our final map considering all forest types yielded an overall accuracy of 86%. Forest disturbance rates were generally higher on the Cambodian side of the border. Frontier forest disturbance rates averaged 3.8%/year in Cambodia compared to 2.5%/year in Vietnam. Conversion to rubber was the dominant form of frontier forest change in both countries (42% in Cambodia and 84% in Vietnam). Non-frontier forest disturbances averaged 4.0% and 2.5% in Cambodia and Vietnam, respectively, with most disturbances likewise linked with rubber plantations. Although rates of frontier forest disturbance differed in both countries, they each displayed similar correlations between disturbance rates related to rubber plantation expansion and price fluctuations of natural rubber. This suggests links between localized land cover/use change and international market forces, irrespective of differing political and socioeconomic backgrounds. Our study underlines the value of using dense Landsat time series when exploring the dynamics of human-induced land cover change.

Differential reactions to anthropogenic disturbance by two ground-nesting shorebirds

Many ground-nesting shorebirds experience a high level of anthropogenic disturbance, often to the detriment of their breeding success. This study investigated the responses of the Near-Threatened African Black Oystercatcher Haematopus moquini (ABO) and the Least Concern Kelp Gull Larus dominicanus vetula (KG) to anthropogenic disturbance during the pre-breeding and breeding season at three locations differing in levels of anthropogenic disturbance and colony size. Birds were directly approached from over 100 m away and markers were dropped at each behavioural reaction to the approach. Measuring back allowed a quantitative measure of the effects of disturbance. Stand response distances in breeding ABO were location sensitive, which related to disturbance level, showing that they stood up earlier in a highly disturbed location. Neither ambient conditions (wind speed and ambient temperature) nor nesting condition (egg age and clutch size) played a significant role in responses. Interestingly, breeding KG behaviour was affected by location, to a lesser extent by clutch size, but not by ambient conditions. Both ABO and KG significantly altered their behavioural responses to disturbance from pre-breeding to breeding. These results emphasise the need to have a buffer zone surrounding breeding areas excluding human presence to allow for the successful breeding of ABO.

Assessment of the physical disturbance of the northern European Continental shelf seabed by waves and currents

Natural seabed disturbance was quantified by estimating the number of days in a year that movement of the seabed occurred due to waves and currents. Disturbance over gravel substrates was based on the concept of a critical threshold for bed movement. For mud substrates disturbance was assessed on the basis of bed failure under extreme hydrodynamic stress. For sand beds the disturbance frequency was calculated by reference to the predicted occurrence of small scale bedforms using established relationships for estimating ripple and megaripple height. The method was applied to the northern European Continental Shelf (48°N to 58.5°N and 10°W to 10°E) using modelled annual wave and current forcing with a temporal resolution of one hour and spatial resolution of approximately 11km. Highest levels of disturbance occurred in areas of high tidal stress where dune/megaripple type bedforms were predicted and in shallow regions exposed to waves with large fetch. However, the detailed distribution of disturbance showed a complex relationship between water depth, tidal stress, wave fetch and grain size. An assessment of the uncertainty in the results was made by use of a simple Monte Carlo approach. In most locations this indicated a large uncertainty in disturbance frequency values suggesting that present predictive relationships need improvement if assessments of natural disturbance are to be made with confidence. Nevertheless the results give a broad understanding of the location and intensity of natural physical bed disturbance and the ability to compare the relative intensity between different regions. This has applications to management of the seabed where human impacts have to be assessed in the context of the underlying natural disturbance. Recommendations are given for further research that might help decrease the uncertainty in natural disturbance prediction.

Automatic Tracking of Pregenesis Tropical Disturbances Within the Deviation Angle Variance System

The deviation angle variance (DAV) method is an objective tool for estimating the intensity of tropical cyclones (TCs) using geostationary infrared (IR) brightness temperature data. At early stages in TC development, the DAV signal can be also a robust predictor of tropical cyclogenesis. However, one of the problems with using the DAV method at these early stages is that the operator has to subjectively track potentially developing cloud systems, sometimes before they are clearly identifiable. Here, we present a method that allows us to automatically track the evolution of cloud clusters using only the raw IR imagery and the resulting DAV maps. We have compared our objective method with results manually obtained on a limited data set spanning a 12-day period during the 2010 hurricane season in the western North Pacific and tuned the performance of the method to the manual results. The performance of the method was then tested by comparing the results with best track and invest files produced by the Joint Typhoon Warning Center for the four-year period 2009-2012. The long-term results agree well with the best track and invest files for the disturbances analyzed in terms of start time, end time, and locations of disturbances. The automatic tracking method presented in this letter may be used to reduce the dependence of tropical cyclogenesis DAV analyses on the expertise and ability of the operator.