Midpoint Of Body Research Articles

Video-based marker-free tracking and multi-scale analysis of mouse locomotor activity and behavioral aspects in an open field arena: A perspective approach to the quantification of complex gait disturbances associated with Alzheimer's disease.

Complex gait disturbances represent one of the prominent manifestations of various neurophysiological conditions, including widespread neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. Therefore, instrumental measurement techniques and automatic computerized analysis appears essential for the differential diagnostics, as well as for the assessment of treatment effectiveness from experimental animal models to clinical settings. Here we present a marker-free instrumental approach to the analysis of gait disturbances in animal models. Our approach is based on the analysis of video recordings obtained with a camera placed underneath an open field arena with transparent floor using the DeeperCut algorithm capable of online tracking of individual animal body parts, such as the snout, the paws and the tail. The extracted trajectories of animal body parts are next analyzed using an original computerized methodology that relies upon a generalized scalable model based on fractional Brownian motion with parameters identified by detrended partial cross-correlation analysis. We have shown that in a mouse model representative movement patterns are characterized by two asymptotic regimes characterized by integrated 1/f noise at small scales and nearly random displacements at large scales separated by a single crossover. More detailed analysis of gait disturbances revealed that the detrended cross-correlations between the movements of the snout, paws and tail relative to the animal body midpoint exhibit statistically significant discrepancies in the Alzheimer's disease mouse model compared to the control group at scales around the location of the crossover. We expect that the proposed approach, due to its universality, robustness and clear physical interpretation, is a promising direction for the design of applied analysis tools for the diagnostics of various gait disturbances and behavioral aspects in animal models. We further believe that the suggested mathematical models could be relevant as a complementary tool in clinical diagnostics of various neurophysiological conditions associated with movement disorders.

Walking through an aperture while penetrating from the paretic side improves safety managing the paretic side for individuals with stroke who had previous falls

Safety management of the paretic side of the body is critical for individuals with stroke. We previously reported that individuals with stroke who walk through an aperture while penetrating from the paretic side had fewer collisions with the frame of an aperture than did those penetrating from the non-paretic side. We observed spontaneous behavior of collision avoidance in our previous study; this study thus used penetration from the paretic and non-paretic sides as independent variables to confirm the usefulness of penetrating from the paretic side. This study aimed to (1) reconfirm whether walking through a narrow space while penetrating from the paretic side leads to reduced frequency of collision only for individuals with stroke with previous falls by manipulating the direction of penetration as independent variables and to (2) determine whether the behavioral or cognitive characteristics of passing through the aperture are observed in individuals with stroke who had previous falls. Individuals with stroke (12 with previous falls, 13 without) were required to walk through a narrow space while penetrating from the paretic and non-paretic sides. The collision rate and kinematic characteristics at the moment of crossing the aperture (body rotation angle, deviation of body's midpoint, and movement speed) were recorded as dependent variables. We also confirmed whether the participants expected collision after passing. Individuals with stroke with previous falls were less likely to have a collision when penetrating from the paretic side. The stroke fall group was likely to experience more collisions because of deleterious changes in body rotation angle and movement speed in narrow apertures. Moreover, individuals with stroke have many unexpected collisions, but the decline in anticipatory ability was not unique to the stroke fall group. Penetrating a narrow space from the paretic side improved safety management of the paretic side in patients with previous falls despite poor adjustment to narrow apertures. Penetrating a narrow space from the paretic side may make it easier to view and pay attention to the paretic side.

29 November 2011 stellar occultation by 2060 Chiron: Symmetric jet-like features

On 29 November 2011 UT, 2060 Chiron occulted a R=14.9-mag star; data were successfully obtained at the 3-m NASA Infrared Telescope Facility (IRTF) on Mauna Kea and 2-m Las Cumbres Observatory Global Telescope Network (LCOGT) Faulkes Telescope North (FTN) at Haleakala. The MORIS lightcurve shows a solid-body detection of Chiron’s nucleus with a chord duration of 16.0±1.4s, corresponding to a chord length of 158±14km. Symmetric, dual extinction features in the FTN light curve indicate the presence of optically thick material roughly 300km from the body midpoint. The duration of the features indicates a 3±2km feature separated by 10–14km from a second 7±2km feature. The symmetry, optical thickness, and narrow size of these features allow for the intriguing possibility of a near-circular arc or shell of material.

The relationship between spatial cognition and walking trajectory for passing through a doorway: evident in individuals with dominant right eye?

When individuals attempt to walk through the center of a doorway (i.e., spatial bisection), the body's midpoint at crossing can deviate from its true center. Such deviation could result from asymmetry in spatial cognition. However, previous studies failed to find a significant correlation between bisection performance during walking and that during line/spatial bisection. We investigated whether such failure would result from different effectors being used for bisection (i.e., body midpoint or finger/laser pointer). We also investigated whether the difference in an individual's eye dominance would affect the relationship. Thirty-two young adults (16 of them with right-eye dominance) participated. For a walking task, participants walked through the perceived center of a wide doorway. For a spatial bisection task, they observed the same doorway under two distance conditions (about 0.5 and 2 m) and aligned their body midpoint with the perceived center in the sagittal dimension. Both tasks were performed under three visual occlusion conditions (dominant eye, non-dominant eye, and no occlusion). The results showed that, for the spatial bisection task, occluding the dominant eye caused deviation of the bisected point to the contralateral side. However, for the walking task, such an effect was observed only in participants with a dominant right eye. Consequently, directional biases in both tasks were significantly correlated only for right-eye-dominant participants. These results suggest that, for right-eye-dominant individuals only, use of the same effector for both tasks showed a clear relationship between the two tasks. Possible explanations for these findings were discussed.

Pattern of 18F-FDG Uptake in the Spinal Cord in Patients With Non-Central Nervous System Malignancy

Retrospective review. To (1) propose a standard method to quantitate 2-deoxy-2-[18F]-fluoro-D-glucose (18F-FDG) uptake in the spinal cord and (2) use this methodology to retrospectively characterize the pattern of uptake within the entire spinal cord using whole-body positron emission tomography/computed tomography (PET/CT) imaging. A physiologic understanding of glucose metabolism within the spinal cord may provide insight regarding infectious, inflammatory, vascular, and neoplastic spinal cord diseases. Institutional review board approval was obtained. A total of 131 consecutive whole-body PET/CT studies from July to August 2004 were reviewed, and using exclusionary criteria of: (1) severe spinal arthropathy or curvature, (2) motion artifact, (3) canal hardware, (4) spinal tumor, and (5) marrow hyperplasia, 92 studies of neurologically intact patients (49 men and 43 women) were selected for a retrospective review of spinal cord 18F-FDG activity. The transaxial CT was used to define the canal and circular regions of interests were placed within the canal at the level of the vertebral body midpoint from C1 to L3. Region of interest total count, area, and maximum standardized uptake value (SUVmax) were recorded. Measurements at L5 served as an internal control. For comparative analysis, the cord-to-background (CTB) ratio was defined as spinal cord SUVmax to L5 SUVmax. Mean CTB decreased along each spinal level from cranial to caudal (P < 0.001). Significant relative increases were observed at the T11-T12 vertebral body levels (P < 0.001). Although insignificant, a relative increase was observed at C4. No significant interactions of age or sex on CTB were observed. The pattern of 18F-FDG uptake within the spinal cord, observed in patients with non-central nervous system malignancy, may be helpful in understanding glucose physiology of spinal cord diseases and warrants further research.

Directional bias in the body while walking through a doorway: its association with attentional and motor factors

Recent studies indicate that cognitively intact individuals experience frequent rightward collisions while walking through narrow doorways. Such a directional bias has been attributed to an attentional bias in spatial perception. However, these studies did not investigate the involvement of any motor factor that could affect the directional bias in the body. In the present study, three experiments were conducted to quantify the impact of the leading foot when crossing a doorway threshold on the directional bias in the body midpoint when passing through the doorway. Participants walked through the perceived center of a relatively wide doorway. Measurements of the deviation of the upper-body midpoint from the center of the doorway demonstrated that the leading foot had a very strong influence on the directional bias. Some participants showed rightward deviation irrespective of which foot was used to step through the doorway (Experiment 1). However, a consistent rightward bias in the body was not observed in other experiments. Both the movement of one hand (Experiment 2) and covert visual attention to one side of the door (Experiment 3) caused contralateral deviation of the body. It is likely that the movement of the hand and a visual stimulus serve as an attentional cue and are effective to avoid neglect of the ipsilateral side; as a result, the body midpoint is deviated to the contralateral side. From these findings, we conclude that the directional bias in locomotor trajectories while passing through a doorway results from the combination of a motor factor, particularly the leading foot, and attentional/brain factors.

Radiologic Landmark Accuracy for Optimum Coronal Placement of Total Disc Arthroplasty in the Lumbar Spine

This study was performed to determine which of the radiographic markers visible on an anteroposterior (AP) radiograph of the spine-the vertebral body, the pedicles, and the spinous process-provided the most accurate guide to correctly placing an intervertebral disc replacement in the coronal midline. The coronal midline was defined as the perpendicular bisector of a line drawn between the midpoints of the two facet joints. Axial CT images were reconstructed from 35 abdominal and renal computed tomograms to compare how consistently the midpoints of the above structures fell on the coronal midline. The mean distance (SD) from the vertebral body midpoint, the interpedicular midpoint, and the spinous process midpoint from the coronal midline, respectively, were 0.55 mm (SD 0.45 mm), 0.19 mm (SD 0.40 mm), and 1.30 mm (SD 1.30 mm). Sixteen percent of the distances from the coronal midline to the spinous process midpoint were greater than or equal to 3 mm compared with 0% of the distances to the interpedicular midpoint or the vertebral body midpoint. We concluded that the interpedicular midpoint is the most accurate guide to the coronal midline. We recommend that this landmark be used in preference to the spinous processes or the midpoint of the vertebral bodies when placing the implant in intervertebral disc arthroplasty.

On a Model of Nonlocal Continuum Mechanics Part II: Structure, Asymptotics, and Computations

We consider the asymptotic behavior and local structure of solutions to the nonlocal variational problem developed in the companion article to this work, On a Model of Nonlocal Continuum Mechanics Part I: Existence and Regularity. After a brief review of the basic setup and results of Part I, we conduct a thorough analysis of the phase plane related to an integro-differential Euler--Lagrange equation and classify all admissible structures that arise as energy minimizing strain states. We find that for highly elastic materials with relatively weak particle-particle interactions, the maximum number of internal phase boundaries is two. Moreover, we also develop explicit bounds for the number of internal phase boundaries supported by any material and show that this bound is essentially inversely related to the particle size. To understand the question of asymptotics, we utilize the Young measure and show that in the sense of energetics and averages, minimizers of the full nonlocal problem converge to minimizers of two limiting problems corresponding to both the large and small particle limits. In fact, in the small particle limit, we find that the minimizing fields converge, up to a subsequence in strong-Lp, for 1 ≤ p < ∞, to fields that support either a single internal phase boundary, or two internal phase boundaries that are distributed symmetrically about the body midpoint. We close this work with some computations that illustrate these asymptotic limits and provide insight into the notion of nonlocal metastability.

Parabrosmolus novaeguineae, a new genus and species of the subfamily Brosmophycinae from Papua New Guinea (Bythitidae, Ophidiiformes)

Parabrosmolus novaeguineae, a new genus and species of the subfamily Brosmophycinae (family Bythitidae) is described, based on a single specimen from Papua New Guinea. The genus is unique in the tribe Brosmophycini in having six branchiostegal rays and ten precaudal vertebrae, and is also similarly distinguished from two brosmophycine genera,Melodichthys andBeaglichthys, tribal allocations of the two latter being uncertain.Parabrosmolus also differs from all other genera in the subfamily by the following combination of characters: head scaly, anal fin origin slightly before midpoint of body, eye diameter shorter than snout length, three developed rakers on first gill arch and 16 (14+2) caudal fin rays.

Two new genera and species of the subfamily Brosmophycinae (Bythitidae, Ophidiiformes) from Northern Australia

Two new bythitid genera and species of the subfamily Brosmophycinae are described from Northern Territory, Australia.Brosmolus longicaudus, described from a single male specimen, is unique in the tribe Brosmophycini in having the anal fin origin well anterior to the midpoint of the body and thin, transparent skin on the head and body.Beaglichthys macrophthalmus, described from a single female specimen, differs from all other genera in the subfamily by the following combination of characters: eight branchiostegal rays, eye diameter longer than snout length, cheek scaly, anal fin origin at midpoint of body, three developed rakers on the first gill arch, 12 caudal fin rays, and 14 precaudal vertebrae.

Arhythmorhynchus capellae sp. n. (Polymorphidae: Acanthocephala), a Parasite of the Common Snipe Capella gallinago delicata

Arhythmorhynchus capellae sp. n. is described. The description is based on seven males and seven females from the Common Snipe in northern Colorado. The species is contrasted with two similar species, A. comptus Van Cleave and Rausch, 1950 and A. eroliae (Yamaguti, 1939) Van Cleave and Rausch, 1950. It differs from the former in having 14 proboscis hooks per row rather than eight or nine, and from the latter in having no bursal rays and 16 rows of 14 hooks rather than 18 rows of 12 to 13 hooks. This species is described from 14 specimens, seven males and seven females, recovered from the small intestines and ceca of six Common Snipe Capella gallinago delicata taken between January 1961 and March 1962 in northeastern Colorado. All measurements are in microns unless otherwise indicated. Arhythmorhynchus capellae sp. n. Description: Bright yellow and wrinkled when removed from gut. Trunk long and narrow with slight inflation at anterior end. Proboscis nearly cylindrical, armed with 16 longitudinal rows of 14 hooks each, 50 long and not appreciably heavier midventrally; the first three and last four hooks in each row more delicate, measuring 42 to 45 long. Neck about 350 long. Body spines extend about 1.74 mm posterior from neck, less numerous toward rear; length 30 to 35. Subcuticular nuclei restricted to narrow band at swollen area of trunk. Male: Length 12 to 41 mm (35 mm); diameter at midpoint of body 222 to 666 (494). Proboscis length 610 to 721 (653); width 144 to 200 (166). Armature same in male and female. Two testes contiguous, each about 1.43 mm long, located 1.10 to 1.30 mm behind field of body spines. Two tubular cement glands extend from area immeReceived for publication 17 September 1962. * Part of a thesis submitted to the Graduate School of Colorado State University in partial fulfillment of the requirements for the degree of Master of Science, March 1962, under the direction of Dr. O. W. Olsen. This investigaiton was in part supported by a training grant [PHS-2E-94 (cl)] from the Institute of Allergy and Infectious Diseases of the National Institutes of Health, U. S. Public Health Service. diately behind posterior testis and join common sperm duct posterior to Saefftigen's pouch.

Two Spinning Mites Attacking the Incense Cedar in California

Female.—Ground color rusty-green-amber, with a dark green lateral area which embraces a number of blackish spots and blotches; most of cephalothorax, and median portion of abdomen paler. Legs and palpi rusty greenish amber. A single perfect eye cornea on each side, deep carmine. Body setae pale, large for the size of the mite, not arising from tubercles, 26 in number. Body broadly oval, widest across middle of cephalothorax. A series of measured females averaged 0.259 mm. long by 0.201 mm. wide. Anterior margin of cephalothorax conspicuously truncated. Mandibular plate abnormally large, often more than half length of body; emarginate anteriorly in younger stages, becoming rounded at maturity. Location of main dorsal suture aberrant in that it occurs behind midpoint of body, thus resulting in a greatly reduced abdomen. “Thumb” of palpus much shortened axially, considerably thicker than long, bearing at its tip a non-clavate “finger” which is only slightly longer than thick; the clavate dorsal sensilla is diminutive compared to the terminal “finger”; just dorsad of the terminal “finger” arise the customary pair of digituli which are tacklike, and exceed somewhat the tenninal sensilla; a short hair arises near the base of the dorsal sensilla, and a stronger pedestaled seta arises dorsally from the “thumb” near its base; a hair arises laterally from near the ventrodistal angle of “thumb.” Legs rather short, foreleg not over four-fifths the length of the body, well supplied with strong hairs. Relative lengths of the joints of foreleg as follows: Coxa, 16; trochanter, 18; femur, 20; patella, 16; tibia, 16; tarsus, 18. Tip of tarsus (female) supplied with a strong, gently curving claw; at a point about one-fifth the length of the claw from its base arise six straightish spurs whose tips about equal that of the main claw; four tenent hairs, as usual, arise in pairs on either side of the base of the main claw. Collar trachea extending downward and backward as a straightish narrow tube, ending in a slightly enlarged chamber. Egg distinctly flattened (lenticular).