Digital Videography Research Articles

Automation within digital videography: from the Ken Burns Effect to ‘meaning-making’ engines

A key feature of entry-level software tools is the emergence of various forms of automation to allow quick and easy generation of short video material. Higher level forms of automation are prevalent particularly at the prosumer or entry-level end of software culture, and illustrate how software culture serves more broadly as a realm for the evolution of hybrid assemblages of human and nonhuman. This paper addresses a number of patterns of automated practices within software-based videography, including the Ken Burns Effect and the emergence of mechanisms we can identify as ‘meaning-making engines’. These enable the harvesting and curating of networked material into a variety of cultural forms, encouraging both individual and collaborative practices that engage with all manner of data structures (including video). This part of the digital ecology is still in its early stages but nonetheless features experimentation with and expansion of ‘meaning-making’ practices that have implications for the nature and ‘evolution’ of user-generated culture (and for emerging documentary practices).

The origin and formation of hair on external valve surfaces of the tropical marine mussel Modiolus traillii (Reeve, 1857)

Direct observations using digital videography in an aquarium showed that hairs on the valve surfaces of Modiolus traillii are not periostracal in origin, as often assumed for similar features in other mussels, but are secreted and planted individually by the foot, so they are correctly termed ‘byssal hairs’. Deposition of byssal hair occurred most frequently just after dark, and the time taken to form a strand of serrated hair varied between slightly more than 1 min to almost 10 min, with a mean time of 4.4 min. We observed one individual deposit a total of 11 hairs in 3.5 h. The formation of some 25 hairs were successfully observed on video for six individuals, and about 3,000 individual hairs from 12 mussels were measured in relation to their position, size and density. While hairs varied considerably in length and width, they are consistently flattened, with one edge bearing serrations and the other edge being smooth. Long hair required more time to form compared with shorter hair, and longer hair was deposited farther away from the byssal gape towards the posterior end of the valves. However, a higher density of short hair was laid around the byssal gape. Smaller mussels tended to have an overall higher density of hair compared with larger individuals. There was no discernible pattern in the order in which long and short hairs were secreted on the periostracal surfaces of either valve. Byssal hair microstructure was generally consistent with the distal region of byssal threads, having a tough but thin outer cortex surrounding a ‘spongy’ honeycomb matrix.

Prenatal ontogeny of the dopamine‐dependent neurobehavioral phenotype in Pitx3‐deficient mice

Mouse models with prenatal alterations in dopaminergic functioning can provide new opportunities to identify fetal behavioral abnormalities and the underlying neural substrates dependent on dopamine. In this study, we tested the hypothesis that prenatal loss of nigrostriatal function is associated with fetal akinesia, or difficulty initiating movement. Specific behaviors were analysed in fetal offspring derived from pregnant Pitx3(ak) /2J and C57BL/6J dams on the last 4days before birth (E15-18 of a 19-day gestation). Using digital videography, we analysed: (i) behavioral state, by quantification of high- and low-amplitude movements, (ii) interlimb movement synchrony, a measure of the temporal relationship between spontaneous movements of limb pairs, (iii) facial wiping, a characteristic response to perioral tactile stimulation similar to the defensive response in human infants, and (iv) oral grasp of a non-nutritive nipple, a component of suckling in the human infant. Pitx3 mutants showed a selective decrease in interlimb movement synchrony rates at the shortest (0.1s) temporal interval coupled with significantly increased latencies to exhibit facial wiping and oral grasp. Collectively, our findings provide evidence that the primary fetal neurobehavioral deficit of the Pitx3 mutation is akinesia related to nigrostriatal damage. Other findings of particular interest were the differences in neurobehavioral functioning between C57BL/6J and Pitx3 heterozygous subjects, suggesting the two groups are not equivalent controls. These results further suggest that fetal neurobehavioral assessments are sensitive indicators of emerging neural dysfunction, and may have utility for prenatal diagnosis.

In Situ Qualitative Inspection of Hole Exit Delamination at Bottom‐Ply during Drilling of Woven CFRP Epoxy Composite Laminates

AbstractExploiting very high speed digital videography, an in situ examination of the hole exit delamination at the bottom‐most ply during drilling holes in the selected woven CFRP epoxy laminates is presented. At the beginning, a rotating elastic bulge of the carbon fibers at the bottom‐ply, which is just the impression of the protruding drill chisel edge, was always observed. Following the elastic bulging, a few, initial cracks along the weak fiber/matrix interfaces appeared. Thereafter, tensile failures in the carbon fibers were seen. The exact location of the initiation of these fiber failures specifically depends on the actual drill‐hole position with respect to the woven configuration of the bottom‐ply. A visual model for the weak interstitial or undulated regions at the bottom‐ply is also proposed in this paper, showing the undulating fibers, which are susceptible to mostly tensile failures under the drilling loads. During a sub‐completion drilling‐phase at the bottom‐ply, various cracks were seen to be propagating mostly via linear paths. Also, the exit delamination at the bottom‐ply during a sub‐completion drilling‐phase was always observed as to be divided into various small, independent localized contours—each of which propagated almost independently through within several individual warps/wefts during drill‐feed. Also, the shape of each such tiny contour within a single warp/weft was identified as elliptic, which is observed around an entire drill‐hole in unidirectional (UD) composites as reported in literature. It was also observed that the overhanging cantilever‐like fibers at the bottom‐ply are really difficult to cut, once their base‐location or their exit delamination contour reaches outside the hole nominal diameter. Moreover, by referring to some very basic cutting angle configurations for the orthogonal trimming of UD‐composites as found rarely in archival literature, an illustrative model diagram is also proposed for the drilling of the selected laminate material. This idea is also approximately validated via a few visual observations. The proposed visual model is generally an attempt in correlating the observed peripheral hole quality (delamination) with various instantaneous tool/fiber engagement configurations occurring across the entire drill‐hole periphery at the bottom‐ply, during the very last drilling‐phase.

Interviews with pioneers of vascular surgery

The purpose of the SVS is not just to hold an annual meeting, but also to pursue social, financial, and political responsibilities. In addition, the Society leads in research, training, education, and practice (ie, patient care). The current leadership of the SVS is dedicated to preserving the history of the Society. The History Project Work Group will execute the orders of the Society to develop a series of digital videography recorded interviews with leaders in vascular surgery to be made available to our membership. The information collected will form the basis for a book on the history of the SVS.

Big Brother is Watching: Studying Insect Predation in the Age of Digital Surveillance

We describe a novel video system constructed from readily available security equipment for recording insect predator behavior in the field. Our system consists of a multi-channel digital video recorder (DVR), active night vision cameras, a deep cycle marine battery, and a weatherproof housing. The major advantages of these systems over previous generations of video equipment include reduced expense, improved deployment times, faster frames per second, and higher video resolution. We tested our systems in a pair of experiments: the first assessed the effects of ground cover on predation of key pests in blueberries, and the second investigated predator activity in corn and perennial prairie systems. We identified ants as the most frequent predators in all three ecosystems, with notable activity from arachnids, crickets, and mollusks. Interactions between coleopterans and prey were surprisingly infrequent in all three agroecosystems. Ants were observed under both day and night conditions, while other predators were primarily nocturnal. Ground covers did not significantly affect predator activity in blue-berries, but there was a numerical reduction in ant activity on woodchips and weed barrier compared to grass and bare ground. The predator complex observed in blueberry video footage differed considerably from pitfall captures at the same site. In corn fields, prey mortality significantly increased with ant activity, and high prey mortality was associated with long interactions that involved large numbers of ant foragers. Digital videography of insect predators is a very useful tool for identifying key taxa responsible for the removal of sentinel prey and documenting their behavior.

Capillary Refill Time

Capillary refill time (CRT) is widely used by health care workers as part of the rapid, structured cardiopulmonary assessment of critically ill patients. Measurement involves the visual inspection of blood returning to distal capillaries after they have been emptied by pressure. It is hypothesized that CRT is a simple measure of alterations in peripheral perfusion. Evidence for the use of CRT in anesthesia is lacking and further research is required, but understanding may be gained from evidence in other fields. In this report, we examine this evidence and factors affecting CRT measurement. Novel approaches to the assessment of CRT are under investigation. In the future, CRT measurement may be achieved using new technologies such as digital videography or modified oxygen saturation probes; these new methods would remove the limitations associated with clinical CRT measurement and may even be able to provide an automated CRT measurement.

Smile line assessment comparing quantitative measurement and visual estimation

Esthetic analysis of dynamic functions such as spontaneous smiling is feasible by using digital videography and computer measurement for lip line height and tooth display. Because quantitative measurements are time-consuming, digital videography and semiquantitative (visual) estimation according to a standard categorization are more practical for regular diagnostics. Our objective in this study was to compare 2 semiquantitative methods with quantitative measurements for reliability and agreement. The faces of 122 male participants were individually registered by using digital videography. Spontaneous and posed smiles were captured. On the records, maxillary lip line heights and tooth display were digitally measured on each tooth and also visually estimated according to 3-grade and 4-grade scales. Two raters were involved. An error analysis was performed. Reliability was established with kappa statistics. Interexaminer and intraexaminer reliability values were high, with median kappa values from 0.79 to 0.88. Agreement of the 3-grade scale estimation with quantitative measurement showed higher median kappa values (0.76) than the 4-grade scale estimation (0.66). Differentiating high and gummy smile lines (4-grade scale) resulted in greater inaccuracies. The estimation of a high, average, or low smile line for each tooth showed high reliability close to quantitative measurements. Smile line analysis can be performed reliably with a 3-grade scale (visual) semiquantitative estimation. For a more comprehensive diagnosis, additional measuring is proposed, especially in patients with disproportional gingival display.

Evaluating Airborne Multispectral Digital Video to Differentiate Giant Salvinia from Other Features in Northeast Texas

Giant Salvinia (Salvinia molesta) is one of the world’s most invasive aquatic weeds. We evaluated the accuracy of airborne multispectral digital video imagery for separating giant salvinia from other aquatic and terrestrial features at a study site located in northeast, Texas. The five-band multispectral digital video imagery was subjected to an unsupervised computer analysis to derive a thematic map of the infested area. User’s and producer’s accuracies of the giant salvinia class were 74.6% and 87.2%, respectively. Aerial multispectral digital videography has potential as a remote sensing tool for differentiating giant salvinia from other terrestrial and aquatic features.

Damselfly females prefer hot males: higher courtship success in males in sunspots

Males of some territorial calopterygid damselflies show an elaborate courtship display that involves high-frequency wing-beats directed toward an incoming female. Although it has been suggested that female mate preference is based on some characteristics of male’s courtship display, it is unclear whether the courtship display varies between males or is influenced by environmental conditions. We combined two recent technologies, thermographic imaging and high-speed digital videography, to show that the wing-beat frequency during courtship (i.e., courtship intensity) in a damselfly, Mnais costalis, is correlated with thorax temperature. Our data indicated that (1) male thorax temperature was associated with solar exposure in his territory, (2) environmentally derived thermal gain enhanced courtship intensity, (3) hotter males were more likely to copulate than others, and (4) female thorax temperature during oviposition within a territory was associated with solar exposure. Males with territories that have longer exposure to sun spots are expected to attain higher thorax temperatures for longer and so are able to successfully court more females. We suggest that females benefit from mating with hot males because they will be on a warmer territory while ovipositing. Hot males might also have greater mate guarding ability, and/or eggs may develop faster in warmer territories.

How a heavy‐bodied snake strikes quickly: high‐power axial musculature in the puff adder (Bitis arietans)

Despite being large, heavy-bodied snakes, puff adders (Bitis arietans) are capable of achieving strike velocities and accelerations similar to, or greater than, those of much smaller snakes (means of 2.6 and 72 m/sec(2), respectively). The mechanistic basis of the strike was examined using high-speed digital videography, coupled with electromyographic (EMG) analysis, of the two main extensors of the vertebral column, the semispinalis and longissimus. Although the strike involves the rapid extension of preformed body curves, the extensor muscles were not electrically active during body extension. The vertebral extensor muscles exhibited bursts of electrical activity before the onset of movement-and quantified features of these EMG signals were significantly related to kinematic aspects of the strike (e.g., acceleration)-however, this electrical activity terminated shortly (approximately 50 msec) before the onset of movement. It is hypothesized that the prestrike activity of the extensor muscles functions to place the (extensive) musculo-tendon complex of the snake's epaxial muscles under tension, and that the displacement of the body during the strike is due to the elastic recoil of this musculo-tendon complex. Incorporation of this type of elastic recoil would increase the power output of the vertebral extensors. Power amplification of the vertebral extensors may be an evolutionary necessity if a large, heavy-bodied snake, like B. arietans, is going to achieve rapid acceleration during the strike.

Using the NAFX to Measure the Effectiveness over Time of Gene Therapy in Canine LCA

To use ocular motility recordings to determine the changes over time of infantile nystagmus syndrome (INS) in RPE65-deficient canines with Leber Congenital Amaurosis (LCA) and assess the time course of the recalibration of the ocular motor system (OMS). Nine dogs were treated bilaterally with AAV-RPE65. A second cohort of four dogs was treated with AAV2.RPE65, an optimized vector. Their fixation eye movements were recorded before treatment and at 4-week intervals for 3 months, by using high-speed (500 Hz) digital videography. The dogs were suspended in a sling and encouraged to fixate on distant (57 inches) targets at gaze angles varying between +/-15 degrees horizontally and +/-10 degrees vertically. The records for each eye were examined for qualitative changes in waveform and for quantitative changes in centralisation with the expanded nystagmus acuity function (NAFX) and compared with ERG results for restoration of receptor function. First group: Before treatment, five of the dogs had clinically apparent INS with jerk, pendular, or both waveforms and with peak-to-peak amplitudes as great as 15 degrees . One dog had intermittent nystagmus. At the 1- and 2-month examinations, no change in nystagmus waveform or NAFX was observed in any of the initial dogs, while at 10 weeks, one dog treated bilaterally with the standard dosage showed reduced nystagmus in only one eye. The other eye did not respond to treatment, as confirmed by ERG. This result was unexpected since it was previously documented that unilateral treatment leads to bilateral reduction of INS. The other dog treated with the standard dosage showed no reduction of its small-amplitude, high-frequency pendular nystagmus despite positive ERG responses. Second group: Only one dog of the four had clinically detectable INS, similar in characteristics to that seen in the affected dogs of the first group. Unlike any previous dog studied, this one showed a damping of the nystagmus within the first 4 weeks after treatment. In all but one of the cases in which OMS recalibration occurred, as measured by the clinical appearance of nystagmus and by quantitative measurement using the NAFX, the improvement was apparent no sooner than 10 weeks after treatment. Longer term, dose-related studies are needed to determine the minimum necessary degree of restored receptor functionality, the duration after rescue for recalibration of the OMS, and the conditions under which recalibration information can successfully affect the contralateral eye.

Evaluation of two nitrous oxide scavenging systems using infrared thermography to visualize and control emissions

The authors conducted a study to determine the effectiveness of two waste anesthetic gas-scavenging systems. They also evaluated one of the systems to determine the effect of work practices in controlling waste nitrous oxide (N2O). The authors collected a minimum of 13 data sets in each phase of the study that included infrared thermography, digital videography and real-time air analysis for ambient concentrations of waste N2O. Surgeon 1, who had experience using both systems, used the Safe Sedate Dental Mask (Airgas, Radnor, Pa.) system (system I) in phase I and the Porter Nitrous Oxide Sedation System (Porter Instruments, Hatfield, Pa.) (system II) in phase II. Surgeon 2, who did not have experience using system I, used it in phase III. To evaluate each system's effectiveness, the authors collected N2O air concentration data from phases I and II and compared the data with the National Institute for Occupational Safety and Health Recommended Exposure Limit (NIOSH REL). They also compared phases I and III to determine the effect of work practices on the systems' effectiveness. Surgeon 1 controlled occupational exposure to N2O significantly better using system I than using system II. Mean N2O air concentration levels during phases I and II were 61.6 parts per million (ppm) and 225.6 ppm, respectively. Surgeon 2 did not achieve results comparable to those of surgeon 1 in phase I using system I. Infrared thermography and air concentration data suggested that key work practices and patient and surgical variables accounted for the different results obtained in phases I and III. Although neither system was able to control occupational exposure of N2O oxide below the NIOSH REL, system I met the American Conference of Governmental Industrial Hygienists threshold limit value of less than 50 ppm during an eight-hour day and performed significantly better than did system II. System I achieved maximal efficiency when combined with consistent best work practices.

Functional Bases of the Spatial Dispersal of Venom during Cobra “Spitting”

Spitting cobras expulse venom toward the face and/or eyes of potential predators as part of their defensive repertoire. Evaluating the accuracy of the cobras is difficult because the spit venom does not land as a point but rather is distributed, in some cases widely, in complex geometric patterns on the surface of the target. The purpose of this study was to explore the functional bases of the venom's spatial distribution. Using a combination of spatial analysis of "caught" venom, morphology, high-speed digital videography, and electromyography (EMG), three hypothesis were evaluated. Two of these hypotheses--that the spatial distribution was due to differential venom pressure produced by the contractile activity of the adductor mandibulae externus superficiali and that the spatial distribution was produced by the morphology of the venom canal within the fang-were both rejected. The third hypothesis--that the spatial distribution was due to rapid rotational movements of the head about the vertebral column--was supported by analyses of EMG activity within the cervical axial muscles and by predictions of venom-distribution patterns based on these cephalic displacements. These results suggest that the ability to "spit" venom is a unique suite of specializations involving both the axial and the cephalic systems.

Variability of shallow overland flow velocity and soil aggregate transport observed with digital videography

AbstractField experiments at Tiramoana station 30 km north of Christchurch, New Zealand using an erosion plot 16·5 m long, 0·6 m wide, and with a slope of 14–14·5° on rendzina soil aimed to measure the variability of flow velocity and of soil aggregates transport rate in shallow overland flow. Discharge/cross‐section area ratio was used to estimate mean velocity, and high‐speed digital video camera and image analysis provided information about flow and sediment transport variability. Six flow runs with 0·5–3·0 L s−1 discharges were supercritical with Froude numbers close to or more than 1. Mean flow velocity followed Poiseuille law, float numbers were more than 1·5 and hydraulic resistance was an inverse proportional function of the Reynolds number, which is typical for laminar flows. Hence actual velocity varied through time significantly and the power spectrum was of ‘red‐noise’, which is typical for turbulent flow. Sediment transport rates had even higher variability, and soil aggregates transport was a compound Poisson process. Copyright © 2008 John Wiley & Sons, Ltd.

Fish swimming speed variability at constant flow: Galaxias maculatus

Digital videography was used to study the swimming performance of the adult fish Galaxias maculatus in a flume at fixed flows. Instantaneous fish swimming velocities varied about the mean flume velocity and these variations in swimming speed were found to increase as velocity in the flume increased. Standard deviations in swimming velocity measured in the longitudinal direction increased from SD 0.183 m s–1 at U0 = 0.40 m s–1, SD 0.191 at U0 = 0.48 m s–1 to SD 0.237 m s–1 at U0 = 0.60 m s–1. Increases in standard deviations were also seen in cross‐stream and vertical swimming velocities. Similarly, variability in acceleration increased as flume velocity was increased with SD 1.850 m s–2 at U0 = 0.40 m s‐1, SD 2.492 m s–2 at U0 = 0.48 m s–1, and SD 3.125 m s–2 at U0 = 0.60 m s–1 recorded for the longitudinal acceleration component. Maximum swimming velocities of 2.05 m s–1 and accelerations of 25.4 m s–2 were recorded.

A Novel Imaging Technique to Measure Capillary-Refill Time: Improving Diagnostic Accuracy for Dehydration in Young Children With Gastroenteritis

Assessment of dehydration in young children currently depends on clinical judgment, which is relatively inaccurate. By using digital videography, we developed a way to assess capillary-refill time more objectively. Our goal was to determine whether digitally measured capillary-refill time assesses the presence of significant dehydration (> or = 5%) in young children with gastroenteritis more accurately than conventional capillary refill and overall clinical assessment. We prospectively enrolled children with gastroenteritis, 1 month to 5 years of age, who were evaluated in a tertiary-care pediatric emergency department and judged by a triage nurse to be at least mildly dehydrated. Before any treatment, we measured the weight and digitally measured capillary-refill time of these children. Pediatric emergency physicians determined capillary-refill time by using conventional methods and degree of dehydration by overall clinical assessment by using a 7-point Likert scale. Postillness weight gain was used to estimate fluid deficit; beginning 48 hours after assessment, children were reweighed every 24 hours until 2 sequential weights differed by no more than 2%. We compared the accuracy of digitally measured capillary-refill time with conventional capillary refill and overall clinical assessment by determining sensitivities, specificities, likelihood ratios, and area under the receiver operator characteristic curves. A total of 83 patients were enrolled and had complete follow-up; 13 of these patients had significant dehydration (> or = 5% of body weight). The area under the receiver operator characteristic curves for digitally measured capillary-refill time and overall clinical assessment relative to fluid deficit (< 5% vs > or = 5%) were 0.99 and 0.88, respectively. Positive likelihood ratios were 11.7 for digitally measured capillary-refill time, 4.5 for conventional capillary refill, and 4.1 for overall clinical assessment. Results of this prospective cohort study suggest that digitally measured capillary-refill time more accurately predicts significant dehydration (> or = 5%) in young children with gastroenteritis than overall clinical assessment.

Ultrastructure of the archigregarine Selenidium vivax (Apicomplexa) – A dynamic parasite of sipunculid worms (host: Phascolosoma agassizii)

Selenidium vivax is a large and unusual unicellular parasite that inhabits the intestinal lumen of the dotted peanut worm, Phascolosoma agassizii. Molecular phylogenies suggest that this archigregarine lineage diverges near the nexus of the apicomplexan radiation and could shed light on to the early evolution of parasitism within the group. The behaviour and ultrastructure of the trophozoites were described using digital videography and scanning and transmission electron microscopy. The trophozoites were extremely flat and capable of dynamic cellular deformations. An intimate association between a superficial layer of mitochondria and longitudinal clusters of subpellicular microtubules formed a distinct functional configuration that helped explain the mechanism behind the cellular motility. Although inconclusive, the presence of small mitochondria-like profiles and narrow connections between larger mitochondrial profiles suggested that an expansive mitochondrial reticulum might surround the trophozoites. The nucleus was highly convoluted and gave rise to blebs of different sizes. The nuclear blebs were connected to the nucleus proper and surrounded by one cisterna of endoplasmic reticulum, giving the impression of four membrane-bound organelles that were misleadingly reminiscent of apicoplasts. The novel attachment apparatus consisted of a transverse ridge, a linear arrangement of pores that contained thread-like structures and a network of dense bodies and endoplasmic reticulum.

Convergent hydraulics at horseshoe steps in bedrock rivers

Horseshoe waterfalls are a common feature of steep bedrock rivers. As a first step toward understanding their geomorphology, a detailed study of the fluid mechanics at a 0.91-m vertical-drop, horseshoe waterfall was performed in a 2.75-m wide flume. Five non-dimensional upstream energy levels, each with 3–5 non-dimensional downstream tailwater depths (21 runs total), were assessed for water surface topography via digital elevation modeling, flow dynamics via digital videography, and overall energy dissipation via an energy and momentum conservation model. Regardless of tail depth, the horseshoe waterfall was found to have three distinct zones beyond the step brink-1) a nappe whose degree of convergence depends on upstream energy and brink configuration, 2) a convergence zone whose features vary strongly with upstream energy, brink configuration, and tail depth, and 3) a downstream tailwater region whose dynamics primarily depend on tail depth. The centerline nappe profile and brink velocity were reasonably predicted using Rouse's jet trajectory equations when ( H + P)/ H > 2. Peripheral profiles were not predictable using existing equations. For any arbitrary broad-crested step brink configuration, maximum energy dissipation was found to occur when no jump was present and downstream tail depth was exactly critical. Rather than providing maximal energy dissipation, hydraulic jumps below steps provide efficient conversion of kinetic energy to potential energy.

Soil failure associated with crack propagation for an agricultural tillage tool

Tillage loosens soil to depths of 75–150 mm (3–6 in.). As the soil is tilled, the failure path precedes the motion of the tillage tool. Previous studies have examined soil forces acting on a tine by predicting different soil failure patterns. This paper quantifies the rate and the path of the cracks associated with soil failure front. The propagation of the soil failure path by observing the temporal profile of the leading edge of the failure crack with respect to the tool motion was examined. Crack propagations were analysed for sweep operating at 4 km h −1 speed, and two operating depths of 75 and 100 mm using high-speed digital videography. Higher depth of operation showed distinct phases for crack development and propagation. Short and intermittent soil crack propagation with lower propagation growth rates was observed for shallow depth of operation. Crack growth rate has been observed to have a sinusoidal relation with time.