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Sample records for anatomical variation effect

  1. Anatomical variation of cerebral venous drainage: the theoretical effect on jugular bulb blood samples.

    PubMed

    Beards, S C; Yule, S; Kassner, A; Jackson, A

    1998-07-01

    Recent studies have demonstrated significant variation in bilateral jugular venous oxygen saturation measurements which may be of clinical significance. We have therefore measured variations in normal dural sinus venous drainage to assess the possible effects of normal anatomical variations on measured jugular venous oxygen saturation. Normal volunteers (n = 25) were imaged using magnetic resonance venography to demonstrate variations in venous anatomy. Flow was measured in the superior sagittal sinus and bilaterally in the transverse sinus, sigmoid sinus proximal to the jugular bulb and proximal jugular vein using phase difference magnetic resonance imaging. Examination of magnetic resonance venogram images showed considerable variability in the symmetry of transverse sinus flow. Complete absence of one transverse sinus was seen in four cases and significant asymmetry in the size of the transverse sinuses was present in 13. Quantitative flow studies demonstrated that the ratio of superior sagittal sinus to combined jugular bulb flow showed remarkably little variation (0.46 +/- 0.06). Measurements of transverse sinus flow showed significant asymmetry (< 40% of superior sagittal sinus flow in one transverse sinus) in 21 of 25 volunteers. The effect of the observed asymmetry on jugular venous oxygen saturation was modelled based on the assumption of either a supratentorial or infratentorial lesion. This model predicted significant asymmetry in jugular venous oxygen saturation measurements (> 10%) in 65% of cases with a supratentorial lesion which is in close agreement with clinical observations. This study suggests that normal variations in venous drainage may account for observed asymmetry in jugular venous oxygen saturation measurements. PMID:9771169

  2. The effects of anatomic resolution, respiratory variations and dose calculation methods on lung dosimetry

    NASA Astrophysics Data System (ADS)

    Babcock, Kerry Kent Ronald

    2009-04-01

    The goal of this thesis was to explore the effects of dose resolution, respiratory variation and dose calculation method on dose accuracy. To achieve this, two models of lung were created. The first model, called TISSUE, approximated the connective alveolar tissues of the lung. The second model, called BRANCH, approximated the lungs bronchial, arterial and venous branching networks. Both models were varied to represent the full inhalation, full exhalation and midbreath phases of the respiration cycle. To explore the effects of dose resolution and respiratory variation on dose accuracy, each model was converted into a CT dataset and imported into a Monte Carlo simulation. The resulting dose distributions were compared and contrasted against dose distributions from Monte Carlo simulations which included the explicit model geometries. It was concluded that, regardless of respiratory phase, the exclusion of the connective tissue structures in the CT representation did not significantly effect the accuracy of dose calculations. However, the exclusion of the BRANCH structures resulted in dose underestimations as high as 14% local to the branching structures. As lung density decreased, the overall dose accuracy marginally decreased. To explore the effects of dose calculation method on dose accuracy, CT representations of the lung models were imported into the Pinnacle 3 treatment planning system. Dose distributions were calculated using the collapsed cone convolution method and compared to those derived using the Monte Carlo method. For both lung models, it was concluded that the accuracy of the collapsed cone algorithm decreased with decreasing density. At full inhalation lung density, the collapsed cone algorithm underestimated dose by as much as 15%. Also, the accuracy of the CCC method decreased with decreasing field size. Further work is needed to determine the source of the discrepancy.

  3. Quantifying anatomical shape variations in neurological disorders.

    PubMed

    Singh, Nikhil; Fletcher, P Thomas; Preston, J Samuel; King, Richard D; Marron, J S; Weiner, Michael W; Joshi, Sarang

    2014-04-01

    We develop a multivariate analysis of brain anatomy to identify the relevant shape deformation patterns and quantify the shape changes that explain corresponding variations in clinical neuropsychological measures. We use kernel Partial Least Squares (PLS) and formulate a regression model in the tangent space of the manifold of diffeomorphisms characterized by deformation momenta. The scalar deformation momenta completely encode the diffeomorphic changes in anatomical shape. In this model, the clinical measures are the response variables, while the anatomical variability is treated as the independent variable. To better understand the "shape-clinical response" relationship, we also control for demographic confounders, such as age, gender, and years of education in our regression model. We evaluate the proposed methodology on the Alzheimer's Disease Neuroimaging Initiative (ADNI) database using baseline structural MR imaging data and neuropsychological evaluation test scores. We demonstrate the ability of our model to quantify the anatomical deformations in units of clinical response. Our results also demonstrate that the proposed method is generic and generates reliable shape deformations both in terms of the extracted patterns and the amount of shape changes. We found that while the hippocampus and amygdala emerge as mainly responsible for changes in test scores for global measures of dementia and memory function, they are not a determinant factor for executive function. Another critical finding was the appearance of thalamus and putamen as most important regions that relate to executive function. These resulting anatomical regions were consistent with very high confidence irrespective of the size of the population used in the study. This data-driven global analysis of brain anatomy was able to reach similar conclusions as other studies in Alzheimer's disease based on predefined ROIs, together with the identification of other new patterns of deformation. The

  4. Anatomic variations should be considered in total knee arthroplasty.

    PubMed

    Nagamine, R; Miura, H; Bravo, C V; Urabe, K; Matsuda, S; Miyanishi, K; Hirata, G; Iwamoto, Y

    2000-01-01

    The effect of anatomic variations on the operative techniques used in total knee arthroplasty (TKA) was assessed. In 133 Japanese patients with medial osteoarthritis (OA), six parameters were measured on anteroposterior radiographs of the lower extremities taken with the patients in the supine position. The results showed that the characteristics of the knees were bowing of the femoral shaft and proximal tibia vara, with lateral offset of the tibial shaft with respect to the center of the tibial plateau. The angle between a perpendicular to the mechanical axis and the tangent to the distal femoral condyles can be used in determining the external rotation of the femoral component. This angle was more than 3 degrees in 20% of the patients. The femoral component should therefore be externally rotated more than 3 degrees relative to the posterior condylar line in such patients. Because the center of the tibial plateau is located medial to the central line of the tibial shaft in knees with medial OA, the central point of the tibial articular surface should not be used for alignment of the tibial component. The medial offset stem of the tibial component may impinge against the medial wall. Anatomic variations should be evaluated before TKA is attempted. PMID:10982663

  5. Anatomical Variations of Cerebral MR Venography: Is Gender Matter?

    PubMed Central

    Singh, Rambir; Bansal, Nikhil; Paliwal, Vimal Kumar

    2016-01-01

    Purpose Knowledge of variations in the cerebral dural venous sinus anatomy seen on magnetic resonance (MR) venography is essential to avoid over-diagnosis of cerebral venous sinus thrombosis (CVST). Very limited data is available on gender difference of the cerebral dural venous sinus anatomy variations. Materials and Methods A retrospective study was conducted to study the normal anatomy of the intracranial venous system and its normal variation, as depicted by 3D MR venography, in normal adults and any gender-related differences. Results A total of 1654 patients (582 men, 1072 women, age range 19 to 86 years, mean age: 37.98±13.83 years) were included in the study. Most common indication for MR venography was headache (75.4%). Hypoplastic left transverse sinus was the most common anatomical variation in 352 (21.3%) patients. Left transverse sinus was hypoplastic in more commonly in male in comparison to female (24.9% versus 19.3%, p = 0.009). Most common variation of superior sagittal sinus (SSS) was atresia of anterior one third SSS (15, 0.9%). Except hypoplastic left transverse sinus, rest of anatomical variations of the transverse and other sinuses were not significantly differ among both genders. Conclusion Hypoplastic left transverse sinus is the most common anatomical variation and more common in male compared to female in the present study. Other anatomical variations of dural venous sinuses are not significantly differ among both genders. PMID:27621945

  6. The central Onodi cell: A previously unreported anatomic variation

    PubMed Central

    Cherla, Deepa V.; Tomovic, Senja; Liu, James K.

    2013-01-01

    Preoperative recognition of the Onodi cell is necessary to avoid injury to closely associated structures, including the internal carotid artery and the optic nerve. This article describes the central Onodi cell, a variation in which a posterior ethmoid cell lies superior to the sphenoid sinus in a midline position with at least one optic canal bulge. To our knowledge, this anatomic variation has not been previously reported in the literature. Radiographic and endoscopic imaging of this unique variation is provided. PMID:23772328

  7. Presentation of Anatomical Variations Using the Aurasma Mobile App

    PubMed Central

    Bézard, Georg; Lozanoff, Beth K; Labrash, Steven; Lozanoff, Scott

    2015-01-01

    Knowledge of anatomical variations is critical to avoid clinical complications and it enables an understanding of morphogenetic mechanisms. Depictions are comprised of photographs or illustrations often limiting appreciation of three-dimensional (3D) spatial relationships. The purpose of this study is to describe an approach for presenting anatomical variations utilizing video clips emphasizing 3D anatomical relationships delivered on personal electronic devices. An aberrant right subclavian artery (ARSA) was an incidental finding in a routine dissection of an 89-year-old man cadaver during a medical student instructional laboratory. The specimen was photographed and physical measurements were recorded. Three-dimensional models were lofted and rendered with Maya software and converted as Quicktime animations. Photographs of the first frame of the animations were recorded and registered with Aurasma Mobile App software (www.aurasma.com). Resulting animations were viewed on mobile devices. The ARSA model can be manipulated on the mobile device enabling the student to view and appreciate spatial relationships. Model elements can be de-constructed to provide even greater spatial resolution of anatomical relationships. Animations provide a useful approach for visualizing anatomical variations. Future work will be directed at creating a library of variants and underlying mechanism of formation for presentation through the Aurasma application. PMID:26793410

  8. Multiple variations of the tendons of the anatomical snuffbox

    PubMed Central

    Thwin, San San; Zaini, Fazlin; Than, Myo

    2014-01-01

    INTRODUCTION Multiple tendons of the abductor pollicis longus (APL) in the anatomical snuffbox of the wrist can lead to the development of de Quervain's syndrome, which is caused by stenosing tenosynovitis. A cadaveric study was performed to establish the variations present in the tendons of the anatomical snuffbox in a Malaysian population, in the hope that this knowledge would aid clinical investigation and surgical treatment of de Quervain's tenosynovitis. METHODS Routine dissection of ten upper limbs was performed to determine the variations in the tendons of the anatomical snuffbox of the wrist. RESULTS In all the dissected upper limbs, the APL tendon of the first extensor compartment was found to have several (3–14) tendon slips. The insertion of the APL tendon slips in all upper limbs were at the base of the first metacarpal bone, trapezium and fascia of the opponens pollicis muscle; however, in seven specimens, they were also found to be attached to the fleshy belly of the abductor pollicis brevis muscle. In two specimens, double tendons of the extensor pollicis longus located in the third extensor compartment were inserted into the capsule of the proximal interphalangeal joints before being joined to the extensor expansion. In two other specimens, the first extensor compartment had two osseofibrous tunnels divided by a septum that separated the APL tendon from the extensor pollicis brevis tendon. CONCLUSION Multiple variations were found in the anatomical snuffbox region of the dissected upper limbs. Knowledge of these variations would be useful in interventional radiology and orthopaedic surgery. PMID:24452976

  9. Anatomic variation and orgasm: Could variations in anatomy explain differences in orgasmic success?

    PubMed

    Emhardt, E; Siegel, J; Hoffman, L

    2016-07-01

    Though the public consciousness is typically focused on factors such as psychology, penis size, and the presence of the "G-spot," there are other anatomical and neuro-anatomic differences that could play an equal, or more important, role in the frequency and intensity of orgasms. Discovering these variations could direct further medical or procedural management to improve sexual satisfaction. The aim of this study is to review the available literature of anatomical sexual variation and to explain why this variation may predispose some patients toward a particular sexual experience. In this review, we explored the available literature on sexual anatomy and neuro-anatomy. We used PubMed and OVID Medline for search terms, including orgasm, penile size variation, clitoral variation, Grafenberg spot, and benefits of orgasm. First we review the basic anatomy and innervation of the reproductive organs. Then we describe several anatomical variations that likely play a superior role to popular known variation (penis size, presence of g-spot, etc). For males, the delicate play between the parasympathetic and sympathetic nervous systems is vital to achieve orgasm. For females, the autonomic component is more complex. The clitoris is the primary anatomical feature for female orgasm, including its migration toward the anterior vaginal wall. In conclusions, orgasms are complex phenomena involving psychological, physiological, and anatomic variation. While these variations predispose people to certain sexual function, future research should explore how to surgically or medically alter these. Clin. Anat. 29:665-672, 2016. © 2016 Wiley Periodicals, Inc. PMID:26916103

  10. Anatomic variations of anterior cerebral artery cortical branches.

    PubMed

    Stefani, M A; Schneider, F L; Marrone, A C; Severino, A G; Jackowski, A P; Wallace, M C

    2000-01-01

    The anterior cerebral artery (ACA) is a major vessel responsible for the blood supply to the interhemispheric region. The ACA segment after the anterior communicating artery (AComA) origin is called the distal ACA and has central and cortical branches. The cortical branches are distributed in the different regions of the orbital and medial part of the brain. The objects of this study are the anatomical variations found in the distal ACA. In 76 hemispheres the ACA distal branches were injected with latex and dissected under microscope magnification. Vessel diameters and distances between vessel origins and anterior communicating artery were recorded and analyzed. Microsurgical dissection was carried out to demonstrate anatomic variations of these vessels. Average diameter of ACA at origin was 2.61 +/- 0.34 mm and average diameter of cortical branches diameter ranged from 0.79 +/- 0.27 mm to 1.84 +/- 0.3 mm. Distances between vessel origin and AComA ranged from 7.68 +/- 3.91 mm (orbitofrontal) to 112.6 +/- 11.63 mm (inferior internal parietal). This study found anatomical variations: a single (azygos) ACA was present in one case and three in three cases. Crossing branches of the distal ACA to the contralateral hemisphere were present in 26% of the cases. In some cases a single ACA may supply the posterior hemispheric region through crossing branches. This calls attention to potential bilateral brain infarcts due to a single unilateral ACA occlusion. PMID:10873213

  11. The maxillary second molar - anatomical variations (case report).

    PubMed

    Beshkenadze, E; Chipashvili, N

    2015-01-01

    To be acquainted with dental anatomical specificity is of great importance for dental endodontic treatment algorithm. The subject of present publication is 2 clinical cases of upper second molars, detailed characterization of, which is considered very important for enrichment of anatomical knowledge about dental anatomical variations. In one case, the reason for admission to the clinic of a 38-year-old woman was complains as of esthetic character as well as functional misbalance (disturbance of chewing function due to the damage of orthopedic construction). The patient indicated to the existence of coronary defects of large size aesthetic discomforts, damage and discolouration of old orthopedic construction (denture) in maxillary right molar area. According to the data obtained after clinical and visiographical examinations, chronic periodontitis of 17 teeth was identified as a result of incomplete endodontic treatment. According to the data obtained after clinical and visiographical examinations, the diagnosis of chronic periodontitis of 17 teeth was identified, tooth 17 with 2 roots and 2 canals. In the second clinical case, the reason for admission to the clinic of a 39-year-old woman was severe pain in the upper right molar area. The patient indicated to the caries on the tooth 17. After completion of proper survey clinical and visiographical examinations, acute pulpitis (K04.00) - with three roots and 4 canals was diagnosed. In both cases after the proper examinations and agreement with the patients a treatment plan envisaging: 17 teeth endodontic treatment, filling of caries defects and their preparation on one hand for orthopedic construction (denture) and on the other hand for restoration of anatomical integrity by light-cured composite, was scheduled. The present study is designed to prevent complications of endodontic treatment of the second molar, to optimize diagnosis and treatment algorithm, once again proving reliable information indicating to the

  12. Anatomical variation of the inferior mesenteric vein's drainage pattern

    NASA Astrophysics Data System (ADS)

    Zilaie, Mina

    The purpose of this project is to report the variable drainage pattern of the inferior mesenteric vein (IMV) as reported by medical students' observations recorded on anatomical variation data sheets (n = 192). A meta-analysis on the drainage pattern of the inferior mesenteric vein as described in various anatomy resources was conducted (n = 40). The inferior mesenteric vein was observed to drain into the splenic vein, the superior mesenteric vein, and the junction between the superior mesenteric vein and the splenic vein. Anatomy resources do not commonly report all three drainage sites. It is imperative that all these common drainage sites of the inferior mesenteric vein are stated in anatomy resources, so that students are taught realistic human anatomy including its common variations.

  13. Anatomical variation of arterial supply to the rabbit stomach.

    PubMed

    Ikegami, Reona; Tanimoto, Yoshimasa; Kishimoto, Miori; Shibata, Hideshi

    2016-05-01

    Gastric stasis is common in rabbits, and gastrotomy may be performed to cure this pathological condition. Detailed descriptions of the arterial supply to the stomach are essential for this surgical operation, but published descriptions are limited. Here, we investigated anatomical variations of the arterial supply to the stomach in 43 New Zealand White rabbits by injecting colored latex into arteries. We observed that the left gastric artery that arose as the second branch from the celiac artery provided 1-3 parietal and 1-3 visceral branches to the stomach, with various branching patterns depending on the case. In 34 of 43 cases, the left gastric artery ended upon entering the gastric wall at the lesser curvature, whereas in the remaining cases, the artery continued as the hepatic artery without entering the gastric wall. The right gastric artery that branched off from the gastroduodenal artery also supplied the lesser curvature sinistrally but did not anastomose with the left gastric artery. In 40 cases, the hepatic artery provided 1-4 pyloric branches. In the fundic region, the short gastric arteries arose from the splenic artery and varied in number from 2 to 6. The right and left gastroepiploic arteries anastomosed to give 2-7 branches to the greater curvature. The results showed that many variations occurred in the arteries supplying the rabbit stomach, suggesting that such variations should be considered when performing veterinary surgical treatments in rabbits. PMID:26615866

  14. Anatomical variation of arterial supply to the rabbit spleen

    PubMed Central

    IKEGAMI, Reona; TANIMOTO, Yoshimasa; KISHIMOTO, Miori; SHIBATA, Hideshi

    2015-01-01

    The rabbit, which is widely used as an experimental animal and is also popular as a companion animal, has a flat and elongated spleen with the longitudinal hilus running along its visceral surface. The spleen receives via the hilus an arterial supply that is essential for splenic nutrition and normal functioning. However, the distribution and variation of the arteries to the spleen have not been studied in detail. This study investigated anatomical variations of splenic arterial supply in 33 New Zealand White rabbits with a colored latex injection into arteries. We also examined whether the length of the spleen correlated with the number of the splenic branches of the splenic artery. The splenic artery always arose as the first independent branch of the celiac artery and ran along the splenic hilus to usually provide 6 (range, 3 to 10) splenic branches to the spleen. There was a moderate correlation (R=0.6) between the number of splenic branches and the longitudinal length of the spleen. The splenic branches often arose as a trunk or trunks in common with short gastric arteries. The number of common trunk(s) was usually 1 (range, 0 to 4). The data showed that the pattern and number of arterial branches to the spleen varied according to the individual animal, suggesting that such variations should be considered when performing experimental and veterinary surgical treatments in rabbits. PMID:26369291

  15. Anatomical variation of arterial supply to the rabbit stomach

    PubMed Central

    IKEGAMI, Reona; TANIMOTO, Yoshimasa; KISHIMOTO, Miori; SHIBATA, Hideshi

    2015-01-01

    Gastric stasis is common in rabbits, and gastrotomy may be performed to cure this pathological condition. Detailed descriptions of the arterial supply to the stomach are essential for this surgical operation, but published descriptions are limited. Here, we investigated anatomical variations of the arterial supply to the stomach in 43 New Zealand White rabbits by injecting colored latex into arteries. We observed that the left gastric artery that arose as the second branch from the celiac artery provided 1–3 parietal and 1–3 visceral branches to the stomach, with various branching patterns depending on the case. In 34 of 43 cases, the left gastric artery ended upon entering the gastric wall at the lesser curvature, whereas in the remaining cases, the artery continued as the hepatic artery without entering the gastric wall. The right gastric artery that branched off from the gastroduodenal artery also supplied the lesser curvature sinistrally but did not anastomose with the left gastric artery. In 40 cases, the hepatic artery provided 1–4 pyloric branches. In the fundic region, the short gastric arteries arose from the splenic artery and varied in number from 2 to 6. The right and left gastroepiploic arteries anastomosed to give 2–7 branches to the greater curvature. The results showed that many variations occurred in the arteries supplying the rabbit stomach, suggesting that such variations should be considered when performing veterinary surgical treatments in rabbits. PMID:26615866

  16. Generating anatomical variation through mutations in networks – implications for evolution

    PubMed Central

    Bard, Jonathan

    2014-01-01

    Genetic mutation leads to anatomical variation only indirectly because many proteins involved in generating anatomical structures in embryos operate cooperatively within molecular networks. These include gene-regulatory or control networks (CNs) for timing, signaling and patterning together with the process networks (PNs) for proliferation, apoptosis, differentiation and morphogenesis that they control. This paper argues that anatomical variation is achieved through a two-stage process: mutation alters the outputs of CNs and perhaps the proliferation network, and such changed outputs alter the ways that PNs construct tissues. This systems-biology approach has several implications: first, because networks contain many cooperating proteins, they amplify the effects of genetic variation so enabling mutation to generate a wider range of phenotypes than a single changed protein acting alone could. Second, this amplification helps explain how novel phenotypes can be produced relatively rapidly. Third, because even organisms with novel anatomical phenotypes derive from variants in standard networks, there is no genetic barrier to their producing viable offspring. This approach also clarifies a terminological difficulty: classical evolutionary genetics views genes in terms of phenotype heritability rather than as DNA sequences. This paper suggests that the molecular phenotype of the classical concept of a gene is often a protein network, with a mutation leading to an alteration in that network's dynamics. PMID:24934180

  17. Successful Parenchyma-Sparing Anatomical Surgery by 3-Dimensional Reconstruction of Hilar Cholangiocarcinoma Combined with Anatomic Variation.

    PubMed

    Ni, Qihong; Wang, Haolu; Liang, Xiaowen; Zhang, Yunhe; Chen, Wei; Wang, Jian

    2016-06-01

    The combination of hilar cholangiocarcinoma and anatomic variation constitutes a rare and complicated condition. Precise understanding of 3-dimensional position of tumor in the intrahepatic structure in such cases is important for operation planning and navigation. We report a case of a 61-year woman presenting with hilar cholangiocarcinoma. Anatomic variation and tumor location were well depicted on preoperative multidetector computed tomography (MDCT) combined with 3-dimensional reconstruction as the right posterior segmental duct drained to left hepatic duct. The common hepatic duct, biliary confluence, right anterior segmental duct, and right anterior branch of portal vein were involved by the tumor (Bismuth IIIa). After carefully operation planning, we successfully performed a radical parenchyma-sparing anatomical surgery of hilar cholangiocarcinoma: Liver segmentectomy (segments 5 and 8) and caudate lobectomy. MDCTcombined with 3-dimensional reconstruction is a reliable non-invasive modality for preoperative evaluation of hilar cholangiocarcinoma. PMID:27376205

  18. Detection of environmental effects through anatomic pathology.

    PubMed

    Miller, R W

    1985-01-01

    Anatomic pathology has produced considerable knowledge about environmental teratogens and carcinogens. A special disease registry established by a pathologist provided details of the association between oral contraceptives and hepatic neoplams. Pathologists were also involved in establishing in the link between diethylstilbestrol use and clear-cell adenocarcinomas of the vagina. An area of particular interest has been gender and ethnic differences in the incidence of certain diseases. Pathologists further make use of animal studies to investigate the pathogenesis of human tumors. Finally, stored serum or tissue is often used by pathologists to help diagnose diseases retrospectively. Human skin fibroblasts grown in culture and stored have been especially valuable for laboratory research. This chapter briefly highlights some of the milestones in the detection of enviromental effects through anatomic pathology. PMID:2997598

  19. A very unusual anatomical variation and complication of common iliac artery and ureter in retroperitonoscopic ureterolithotomy

    PubMed Central

    Huri, Emre; Akgül, Turgay; Karakan, Tolga; Sargon, Mustafa; Germiyanoğlu, Cankon

    2011-01-01

    Anatomical localization of theureter comes along psoas major muscle and crosses over common iliac artery bifurcation. Common iliac artery aneurysm and impacted atherosclerosis are a rare condition that should be differed from the impacted ureter stone to avoid from undesirable complication. In this case, we present a very unusual anatomical variation and complication of common iliac artery and ureter in retroperitonoscopic ureterolithotomy. PMID:21523238

  20. Effect of anatomic, semi-anatomic and non-anatomic occlusal surface tooth preparations on the adaptation of zirconia copings

    PubMed Central

    Asiri, Waleed; Hefne, Mohammed Jameel

    2014-01-01

    PURPOSE To compare the accuracy of marginal and internal adaptation of zirconia (Zr) copings fabricated on anatomic (A), semi-anatomic (SA) and non-anatomic (NA) occlusal surface preparations. MATERIALS AND METHODS 45 extracted bicuspid teeth were prepared for receiving zirconia crowns, with different occlusal preparation designs A=15, SA=15 & NA=15. The Zr copings were fabricated by using CAD4DENT, CAD/CAM. The copings were adjusted, cemented and were cross sectioned centrally from buccal cusp tip to lingual cusp tip into mesial and distal halves. The copings were examined under electron microscope at ×200 magnification and the measurements were recorded at 9 predetermined areas in micrometers. RESULTS Overall mean gap values for the three groups was found to be 155.93±33.98 µm with Anatomical Occlusal preparation design having the least gap value of 139.23±30.85 µm showing the best adaptation among the groups. Post Hoc Tukey's test showed a statistically significant difference (P=.007) between the means of gap for A & NA preparation designs. Measurements recorded at 9 predetermined points showed variations for the three groups. CONCLUSION Anatomical occlusal preparation designs resulted in better marginal and internal adaptation of Zr copings. There is a considerable variation between the measured marginal and internal gap values for the Zr copings fabricated by the (CAD4DENT-CAD/CAM). This variation may be associated with the lack of standardization of the preparation of teeth, computerized designing of the coping for each tooth, cement used, uniform pressure application during the cementation of the copings, sectioning of the copings and the microscopic measurements. PMID:25551003

  1. Effects of anatomical constraints on tumor growth

    NASA Astrophysics Data System (ADS)

    Capogrosso Sansone, B.; Delsanto, P. P.; Magnano, M.; Scalerandi, M.

    2001-08-01

    Competition for available nutrients and the presence of anatomical barriers are major determinants of tumor growth in vivo. We extend a model recently proposed to simulate the growth of neoplasms in real tissues to include geometrical constraints mimicking pressure effects on the tumor surface induced by the presence of rigid or semirigid structures. Different tissues have different diffusivities for nutrients and cells. Despite the simplicity of the approach, based on a few inherently local mechanisms, the numerical results agree qualitatively with clinical data (computed tomography scans of neoplasms) for the larynx and the oral cavity.

  2. Investigations of Anatomical Variations of the Thorax and Heart, and Anatomical Knowledge for First Year Medical Dental and Podiatry Students

    ERIC Educational Resources Information Center

    Verenna, Anne-Marie

    2013-01-01

    The universal presence of anatomy in healthcare professions is undeniable. It is a cornerstone to each of the clinical and basic sciences. Therefore, further expansion of current anatomical knowledge and effective methods to teach anatomy is essential. In this work, the relationship of the dorsal scapular artery with the trunks of the brachial…

  3. Absence of Flexor Carpi Radialis during an Elective Carpometacarpal Arthroplasty of the Thumb: A Rare Anatomical Variation

    PubMed Central

    Riaz, Muhammad

    2016-01-01

    Purpose. We present an extremely rare anatomical variation of unilateral flexor carpi radialis (FCR) absence. This rare anatomical variation posed a clinical dilemma to us and we highlight the importance of the surgeon being aware of this anatomical variation of an important structure both as a reconstruction tool and as an anatomical landmark. Methods. This anatomical variation of the unilaterally absent FCR was found upon dissection during a carpometacarpal arthroplasty of the thumb. Results. Upon the discovery of an absent FCR tendon, we proceeded with a simple trapeziectomy. Conclusions. We present an extremely rare anatomical variation of unilateral FCR absence. This rare anatomical variation may pose clinical dilemmas to the operating surgeon who aims to utilise the FCR either for tendon transfer, for tendon graft, or, as seen in our case, in the reconstruction of a carpometacarpal excision at the thumb. We highlight this diagnosis of suspicion, which may influence the clinical procedure. PMID:27051425

  4. Unusual Anatomic Variations Associated With Bilateral Ulnar Artery Hypoplasia.

    PubMed

    Ro, Hyung-Suk; Roh, Si-Gyun; Shin, Jin Yong; Lee, Nae-Ho; Yang, Kyung-Moo

    2016-05-01

    Variations and anomalies of upper extremities have been commonly reported in routine dissection, clinical practices, and cadaver studies. Despite ongoing research on arterial variations of upper extremities, the absence of bilateral ulnar artery is extremely rare with only 3 patients reported. As the authors are presenting a successfully treated patient, initially prepped for radial forearm osteocutaneous free flap for treatment on oromandibular defect after a wide resection of head and neck cancer lesion, being confirmed to have bilateral ulnar artery hypoplasia and due to this, the patient had to change her surgical plan to fibular osteocutaneous free flap. PMID:27100648

  5. Quantification and Visualization of Variation in Anatomical Trees

    SciTech Connect

    Amenta, Nina; Datar, Manasi; Dirksen, Asger; de Bruihne, Marleen; Feragen, Aasa; Ge, Xiaoyin; Holst Pedersen, Jesper; Howard, Marylesa; Owen, Megan; Petersen, Jens; Shi, Jie; Xu, Qiuping

    2015-07-01

    This paper presents two approaches to quantifying and visualizing variation in datasets of trees. The first approach localizes subtrees in which significant population differences are found through hypothesis testing and sparse classifiers on subtree features. The second approach visualizes the global metric structure of datasets through low-distortion embedding into hyperbolic planes in the style of multidimensional scaling. A case study is made on a dataset of airway trees in relation to Chronic Obstructive Pulmonary Disease.

  6. Variation in anatomical characteristics in leaves of pecan seedstocks from Mexico and the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaf anatomical traits of Mexican and U.S. pecan [Carya illinoinensis (Wangenh.) K. Koch] seedstocks grown in a single location were studied to determine patterns of ecogeographic variation within the natural range. Stomatal density (SD) was uniform among open-pollinated seedlings of a common mater...

  7. HPV Vaccine Effective at Multiple Anatomic Sites

    Cancer.gov

    A new study from NCI researchers finds that the HPV vaccine protects young women from infection with high-risk HPV types at the three primary anatomic sites where persistent HPV infections can cause cancer. The multi-site protection also was observed at l

  8. Anatomical variation of abductor pollicis longus in Indian population: A cadaveric study

    PubMed Central

    Tewari, Jerina; Mishra, Pravash Ranjan; Tripathy, Sujit Kumar

    2015-01-01

    Background: Many authors have reported the anatomical variation of abductor pollicis longus (APL) around the wrist and its association with de Quervain tenosynovitis (DQT), first carpo-metacarpal arthritis, and trapezio-metacarpal subluxation. From Indian subcontinent, there is only one original article and a few case reports on the variability of APL tendon insertion. Materials and Methods: Fifty formaldehyde preserved cadaveric wrists were dissected to look for the anatomical variation of APL in the Indian population. Results: The APL was found with single tendon in 2, double in 31, triple in 8, and quadruple in 8 extremities. A maximum of 6 tendon-slips were found in one cadaveric wrist. In all hands, the APL had at least one attachment to first metacarpal bone and in 46 hands (92%), there was second insertion to the trapezium bone. Of all tendon-slips of APL (n = 126), 44% of tendons (68 tendons) were inserted into the base of the first metacarpal bone. This was followed by the insertion into the trapezium in 42% tendons (52 tendons). Conclusion: Bi-tendinous APL is commonly observed on the dorsal compartment of the wrist in Indian population and these tendon-slips are commonly attached to the first metacarpal base and trapezium. This variation must be understood by the Indian Orthopedic surgeons as the response to treatment of DQT and reason for first carpo-metacarpal arthritis can be dependent on this anatomical variation. PMID:26538762

  9. Branch of the canalis sinuosus: a rare anatomical variation--a case report.

    PubMed

    Torres, Marianna Guanaes Gomes; de Faro Valverde, Ludmila; Vidal, Manuela Torres Andion; Crusoé-Rebello, Iêda Margarida

    2015-09-01

    The canalis sinuosus (CS) is a neurovascular canal, a branch of the infraorbital canal through which the anterior superior alveolar nerve passes. There are no studies or case reports of anatomical variations related to this canal. A rare case of anatomical variation in the CS is reported that was detected by cone beam computed tomography done in a 47-year-old female as a pre-operative workup before dental implants. In this case, in the region slightly medial to tooth 23, a wide accessory branch from the CS was observed, running an intraosseous course in the inferior and posterior direction up to a foramen located in the hard palate, slightly medial in relation to tooth 23. The location of this branching, as well as its neurovascular component, is important for dental implant planning because of its proximity to the upper teeth. Identification of neurovascular bundles is fundamental to avoid complications for the patient. PMID:25616849

  10. Interfractional Variations in Patient Setup and Anatomic Change Assessed by Daily Computed Tomography

    SciTech Connect

    Li, X. Allen . E-mail: ali@radonc.mcw.edu; Qi, X. Sharon; Pitterle, Marissa; Kalakota, Kapila; Mueller, Kevin; Erickson, Beth A.; Wang Dian; Schultz, Christopher J.; Firat, Selim Y.; Wilson, J. Frank

    2007-06-01

    Purpose: To analyze the interfractional variations in patient setup and anatomic changes at seven anatomic sites observed in image-guided radiotherapy. Methods and Materials: A total of 152 patients treated at seven anatomic sites using a Hi-Art helical tomotherapy system were analyzed. Daily tomotherapy megavoltage computed tomography images acquired before each treatment were fused to the planning kilovoltage computed tomography images to determine the daily setup errors and organ motions and deformations. The setup errors were corrected before treatment and were used, along with the organ motions, to determine the clinical target volume/planning target volume margins. The organ motions and deformations for 3 representative patient cases (pancreas, uterus, and soft-tissue sarcoma) and for 14 kidneys of 7 patients are presented. Results: Interfractional setup errors in the skull, brain, and head and neck are significantly smaller than those in the chest, abdomen, pelvis, and extremities. These site-specific relationships are statistically significant. The margins required to account for these setup errors range from 3 to 8 mm for the seven sites. The margin to account for both setup errors and organ motions for kidney is 16 mm. Substantial interfractional anatomic changes were observed. For example, the pancreas moved up to {+-}20 mm and volumes of the uterus and sarcoma varied {<=}30% and 100%, respectively. Conclusion: The interfractional variations in patient setup and in shapes, sizes, and positions of both targets and normal structures are site specific and may be used to determine the site-specific margins. The data presented in this work dealing with seven anatomic sites may be useful in developing adaptive radiotherapy.

  11. Assessing the anatomical variations of lingual foramen and its bony canals with CBCT taken from 102 patients in Isfahan

    PubMed Central

    Sheikhi, Mahnaz; Mosavat, Farzaneh; Ahmadi, Ahura

    2012-01-01

    Background: Some studies have been performed on assessing the anatomical variations of lingual foramen and its bony canals, in many different countries but no study has been performed in Iran yet. The purpose of this study is to assess the anatomical variations of lingual foramen and its bony canals with cone-beam computed tomography (CBCT) imaging in Isfahan. Materials and Methods: This was a cross-sectional study in which CBCT images taken from 102 patients referred to the Radiology Department of Head and Neck in Esfahan (Iran) University between 2010 and 2011. The presence of the lingual foramen and its bony canals, the locations, sizes, and length were assessed. The distances between the terminal end of lingual canal at the buccal and lingual side from the inferior border of the mandible and alveolar crest were measured. We also evaluated the effect of patient age and gender on the dimensional measurements of the anatomical landmark mentioned above t test, analysis of variance (ANOVA), and pearson's correlation were used for statistical analysis and P value lower than 0.05 was considered significant. Result: All of the CBCT images taken showed the presence of lingual foramen. Of all the participants, 52% of them had two foramens in their images. The mean diameters of the upper and lower lingual foramen were 1.12 and 0.9 mm, respectively. Conclusion: These anatomical landmarks in Isfahan population vary from previous studies. All of the images had at least one lingual foramen which demonstrates high prevalence of this anatomy among Isfehanian population. Therefore, it is recommended to use CBCT imaging for preoperative evaluation prior to installing dental implants. PMID:23814561

  12. Anatomical variations of the recurrent laryngeal nerve in Chinese patients: a prospective study of 2,404 patients

    PubMed Central

    Shao, Tanglei; Qiu, Weihua; Yang, Weiping

    2016-01-01

    The recurrent laryngeal nerve (RLN) shows some anatomical variations that can potentially compromise the safety of thyroid surgery. The purpose of this prospective study was to identify the anatomical variations of the RLN in Chinese patients undergoing thyroid surgery. Between January 2007 and December 2013, 2,404 Chinese patients were hospitalized for thyroid surgery with dissecting of the RLN unilaterally or bilaterally. The patients consisted of 510 men and 1,894 women, with a median age of 45.0 years. Overall 3,275 RLNs, including 1,576 left- and 1,699 right-side nerves, were dissected. The anatomical variations were identified in 690 RLNs, including 305 left- and 385 right-side nerves. We identified as many as seven RLN anatomical variations in Chinese patients. These findings indicate that anatomical variations of the RLN are common, and the identification of these anatomical variations of the RLN can help to minimize the risk of post-operative RLN paralysis. PMID:27146369

  13. Palmaris Longus Muscle's Prevalence in Different Nations and Interesting Anatomical Variations: Review of the Literature.

    PubMed

    Ioannis, Dimitriou; Anastasios, Katsourakis; Konstantinos, Natsis; Lazaros, Kostretzis; Georgios, Noussios

    2015-11-01

    The prevalence of the palmaris longus (PL) muscle varies more than any other muscle in the human body. Its absence across the world ranges between 1.5% and 63.9%. It presents with many different anomalies, discovered either clinically, intraoperatively or after anatomical examination of cadavers. This paper includes recent studies and reports about the presence and variations of the PL muscle, thereby illustrating the differences between ethnic groups, as well as emphasizing the different ways of finding it, during daily clinical and surgical practice. PMID:26491493

  14. Anatomical variations in the brachial plexus roots: implications for diagnosis of neurogenic thoracic outlet syndrome.

    PubMed

    Leonhard, Vanessa; Smith, Riley; Caldwell, Gregory; Smith, Heather F

    2016-07-01

    Neurogenic thoracic outlet syndrome (NTOS) is the most common type of TOS. Typically it results from impingement of the neurovasculature as it passes between the anterior and middle scalene muscles; this classic anatomical relationship being the foundation of clinical diagnosis. Positional testing relies on vascular compromise occurring when the subclavian artery is compressed in this space. This study describes several anatomical variations observed in this relationship. Sixty-five cadavers (35m/30f) were assessed to determine the frequency and extent of brachial plexus branching variants. A total of thirty-one variations from "classic" anatomy were observed (47.7%). In two specimens (3.1%), the entire superior trunk coursed completely anterior to the anterior scalene in a position of relative vulnerability. In 27 instances, a portion of or the entire superior trunk pierced the anterior scalene muscle, and in two, the middle trunk also pierced the muscle belly. Interestingly, while two bilateral branching variations were observed, the majority occurred unilaterally, and almost exclusively on the left side. There were no sex differences in frequency. The high frequency of these variations and their potential to predispose patients to neurogenic TOS suggest that current diagnostic methods may be insufficient in clinical diagnosis. Due to lack of vascular compromise, patients with the piercing variant would not display positive signs on the traditional positional tests. The use of ultrasound to determine the route of the brachial plexus could determine whether this variation is present in patients who suffer from TOS symptoms but lack a diagnosis based on traditional positional testing. PMID:27133185

  15. Anatomical Variations of Brachial Plexus in Adult Cadavers; A Descriptive Study

    PubMed Central

    Emamhadi, Mohammadreza; Chabok, Shahrokh Yousefzadeh; Samini, Fariborz; Alijani, Babak; Behzadnia, Hamid; Firozabadi, Fariborz Ayati; Reihanian, Zoheir

    2016-01-01

    Background: Variations of the brachial plexus are common and a better awareness of the variations is of crucial importance to achieve successful results in its surgical procedures. The aim of the present study was to evaluate the anatomical variations of the brachial plexus in adult cadavers. Methods: Bilateral upper limbs of 32 fresh cadavers (21 males and 11 females) consecutively referred to Guilan legal medicine organization from November 2011 to September 2014, were dissected and the trunks, cords and terminal nerves were evaluated. Results: Six plexuses were prefixed in origin. The long thoracic nerve pierced the middle scalene muscle in 6 cases in the supra clavicular zone. The suprascapular nerve in 7 plexuses was formed from posterior division of the superior trunk. Five cadavers showed anastomosis between medial brachial cutaneous nerve and T1 root in the infra clavicular zone. Terminal branches variations were the highest wherein the ulnar nerve received a communicating branch from the lateral cord in 3 cases. The median nerve was formed by 2 lateral roots from lateral cord and 1 medial root from the medial cord in 6 cadavers. Some fibers from C7 root came to the musculocutaneous nerve in 8 cadavers. Conclusion: The correlation analysis between the variations and the demographic features was impossible due to the small sample size. The findings of the present study suggest a meta-analysis to assess the whole reported variations to obtain a proper approach for neurosurgeons. PMID:27517072

  16. High resolution whole brain imaging of anatomical variation in XO, XX, and XY mice.

    PubMed

    Raznahan, Armin; Probst, Frank; Palmert, Mark R; Giedd, Jay N; Lerch, Jason P

    2013-12-01

    The capacity of sex to modify behavior in health and illness may stem from biological differences between males and females. One such difference--fundamental to the biological definition of sex--is inequality of X chromosome dosage. Studies of Turner Syndrome (TS) suggest that X-monosomy profoundly alters mammalian brain development. However, use of TS as a model for X chromosome haploinsufficiency is complicated by karyotypic mosaicism, background genetic heterogeneity and ovarian dysgenesis. Therefore, to better isolate X chromosome effects on brain development and identify how these overlap with normative sex differences, we used whole-brain structural imaging to study X-monosomic mice (free of mosaicism and ovarian dysgenesis) alongside their karyotypical normal male and female littermates. We demonstrate that murine X-monosomy (XO) causes (i) accentuation of XX vs XY differences in a set of sexually dimorphic structures including classical foci of sex-hormone action, such as the bed nucleus of the stria terminal and medial amygdala, (ii) parietal and striatal abnormalities that recapitulate those reported TS, and (iii) abnormal development of brain systems relevant for domains of altered cognition and emotion in both murine and human X-monosomy. Our findings suggest an unexpected role for X-linked genes in shaping sexually dimorphic brain development, and an evolutionarily conserved influence of X-linked genes on both cortical and subcortical development in mammals. Furthermore, our murine findings highlight the bed nucleus of the stria terminalis and periaqueductal gray matter as novel neuroanatomical candidates for closer study in TS. Integration of these data with existing genomic knowledge generates a set of novel, testable hypotheses regarding candidate mechanisms for each observed pattern of anatomical variation across XO, XX and XY groups. PMID:23891883

  17. Underlying sources of cognitive-anatomical variation in multi-modal neuroimaging and cognitive testing.

    PubMed

    Watson, P D; Paul, E J; Cooke, G E; Ward, N; Monti, J M; Horecka, K M; Allen, C M; Hillman, C H; Cohen, N J; Kramer, A F; Barbey, A K

    2016-04-01

    Healthy adults have robust individual differences in neuroanatomy and cognitive ability not captured by demographics or gross morphology (Luders, Narr, Thompson, & Toga, 2009). We used a hierarchical independent component analysis (hICA) to create novel characterizations of individual differences in our participants (N=190). These components fused data across multiple cognitive tests and neuroanatomical variables. The first level contained four independent, underlying sources of phenotypic variance that predominately modeled broad relationships within types of data (e.g., "white matter," or "subcortical gray matter"), but were not reflective of traditional individual difference measures such as sex, age, or intracranial volume. After accounting for the novel individual difference measures, a second level analysis identified two underlying sources of phenotypic variation. One of these made strong, joint contributions to both the anatomical structures associated with the core fronto-parietal "rich club" network (van den Heuvel & Sporns, 2011), and to cognitive factors. These findings suggest that a hierarchical, data-driven approach is able to identify underlying sources of individual difference that contribute to cognitive-anatomical variation in healthy young adults. PMID:26808332

  18. Underlying sources of cognitive-anatomical variation in multi-modal neuroimaging and cognitive testing

    PubMed Central

    Watson, P.D.; Paul, E.J.; Cooke, G.E.; Ward, N.; Monti, J.M.; Horecka, K.M.; Allen, C.M.; Hillman, C.H.; Cohen, N.J.; Kramer, A.F.; Barbey, A.K.

    2016-01-01

    Healthy adults have robust individual differences in neuroanatomy and cognitive ability not captured by demographics or gross morphology (Luders, Narr, Thompson, & Toga, 2009). We used a hierarchical independent component analysis (hICA) to create novel characterizations of individual differences in our participants (N = 190). These components fused data across multiple cognitive tests and neuroanatomical variables. The first level contained four independent, underlying sources of phenotypic variance that predominately modeled broad relationships within types of data (e.g., “white matter,” or “subcortical gray matter”), but were not reflective of traditional individual difference measures such as sex, age, or intracranial volume. After accounting for the novel individual difference measures, a second level analysis identified two underlying sources of phenotypic variation. One of these made strong, joint contributions to both the anatomical structures associated with the core fronto-parietal “rich club” network (van den Heuvel & Sporns, 2011), and to cognitive factors. These findings suggest that a hierarchical, data-driven approach is able to identify underlying sources of individual difference that contribute to cognitive-anatomical variation in healthy young adults. PMID:26808332

  19. Preserving and sharing examples of anatomical variation and developmental anomalies via photorealistic virtual reality.

    PubMed

    Nieder, Gary L; Nagy, Frank; Wagner, Lynn A

    2004-01-01

    Computer graphics technology has made it possible to create photographic-quality virtual specimens from real anatomical material. One technique for doing this, QuickTime Virtual Reality (QTVR), results in virtual specimens that are easily shared on the Internet and displayed as standalone entities or incorporated into complex programs or Web sites. A compelling use of this technology is the sharing of rare specimens such as unusual variations, developmental anomalies or gross pathology. These types of specimens have traditionally been confined to anatomical museums, but could serve a much more useful existence as freely shared virtual specimens. An example presented here is a relatively rare developmental defect in the embryonic aortic arches that results in a right-sided aortic arch coursing posterior to the trachea and esophagus. In a time of ever increasing restraints on the practical side of anatomy education, an Internet-based library of human variation and other rare specimens would be a useful supplement to students' limited exposure to the human body. Since the discovery and preparation of specimens would be the rate-limiting step in producing such a collection, we propose the establishment of a center for virtual specimen creation and preservation through a cooperative effort by gross anatomists and pathologists in contributing the source material. This collection, a work in progress, is available at www.anatomy.wright.edu/qtvr. PMID:14750190

  20. Hormonal and anatomical effects of apple rootstocks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In greenhouse experiments, two-year-old 'Fuji' apple scions (Malus ×domestica, 'Fuji') on size-controlling rootstocks (dwarfing to vigorous), were grown for one season and shoot growth was measured to confirm size-controlling effects. In the next season, xylem sap was collected to determine hydraul...

  1. Anatomical Variations of Cystic Ducts in Magnetic Resonance Cholangiopancreatography and Clinical Implications

    PubMed Central

    Sarawagi, Radha; Sundar, Shyam; Gupta, Sanjeev K.; Raghuwanshi, Sameer

    2016-01-01

    Background. Anatomical variations of cystic duct (CD) are frequently unrecognized. It is important to be aware of these variations prior to any surgical, percutaneous, or endoscopic intervention procedures. Objectives. The purpose of our study was to demonstrate the imaging features of CD and its variants using magnetic resonance cholangiopancreatography (MRCP) and document their prevalence in our population. Materials and Methods. This study included 198 patients who underwent MRCP due to different indications. Images were evaluated in picture archiving communication system (PACS) and variations of CD were documented. Results. Normal lateral insertion of CD at middle third of common hepatic duct was seen in 51% of cases. Medial insertion was seen in 16% of cases, of which 4% were low medial insertions. Low insertion of CD was noted in 9% of cases. Parallel course of CD was present in 7.5% of cases. High insertion was noted in 6% and short CD in 1% of cases. In 1 case, CD was draining into right hepatic duct. Congenital cystic dilation of CD was noted in one case with evidence of type IV choledochal cyst. Conclusion. Cystic duct variations are common and MRCP is an optimal imaging modality for demonstration of cystic duct anatomy. PMID:27313891

  2. Foliar anatomical and morphological variation in Nothofagus pumilio seedlings under controlled irradiance and soil moisture levels.

    PubMed

    Ivancich, Horacio S; Lencinas, María V; Pastur, Guillermo J Martínez; Esteban, Rosina M Soler; Hernández, Luis; Lindstrom, Ivone

    2012-05-01

    Foliar anatomy and morphology are strongly related to physiological performance; therefore, phenotypic plasticity in leaves to variations in environmental conditions, such as irradiance and soil moisture availability, can be related to growth rate and survivorship, mainly during critical growth phases, such as establishment. The aim of this work was to analyze changes in the foliar internal anatomy (tissue proportions and cell dimensions) and external morphology (leaf length, width and area) of Nothofagus pumilio (Poepp. et Endl.) Krasser seedlings growing in a greenhouse under controlled irradiance (three levels) and soil moisture (two levels) during one growing season (measured three times), and to relate them to physiological traits. Three irradiance levels (4, 26 and 64% of the natural incident light) and two soil moisture levels (40 and 80% soil capacity) were evaluated during November, January and March. Internal foliar anatomy of seedlings was analyzed using digital photographs of histological cuttings, while leaf gross morphology was measured using digital calipers and image analysis software. Most internal anatomical variables presented significant differences under different irradiance levels during the growing season, but differences were not detected between soil moisture levels. Palisade parenchyma was the tissue most sensitive to irradiance levels, and high irradiance levels (64% natural incident light) produced greater values in most of the internal anatomical variables than lower irradiance levels (4-24% natural incident light). Complementarily, larger leaves were observed in medium and low irradiance levels, as well as under low soil moisture levels (40% soil capacity). The relationship of main results with some eco-physiological traits was discussed. Foliar internal anatomical and external morphological plasticity allows quick acclimation of seedlings to environmental changes (e.g., during harvesting). These results can be used to propose new

  3. Anatomical Variations in the Sinoatrial Nodal Artery: A Meta-Analysis and Clinical Considerations

    PubMed Central

    Roy, Joyeeta; Ramakrishnan, Piravin Kumar; Hsieh, Wan Chin; Walocha, Jerzy A.; Tomaszewski, Krzysztof A.

    2016-01-01

    Background and Objective The sinoatrial nodal artery (SANa) is a highly variable vessel which supplies blood to the sinoatrial node (SAN). Due to its variability and susceptibility to iatrogenic injury, our study aimed to assess the anatomy of the SANa and determine the prevalence of its anatomical variations. Study Design An extensive search of major electronic databases was performed to identify all articles reporting anatomical data on the SANa. No lower date limit or language restrictions were applied. Anatomical data regarding the artery were extracted and pooled into a meta-analysis. Results Sixty-six studies (n = 21455 hearts) were included in the meta-analysis. The SANa usually arose as a single vessel with a pooled prevalence of 95.5% (95%CI:93.6–96.9). Duplication and triplication of the artery were also observed with pooled prevalence of 4.3% (95%CI:2.8–6.0) and 0.3% (95%CI:0–0.7), respectively. The most common origin of the SANa was from the right coronary artery (RCA), found in 68.0% (95%CI:55.6–68.9) of cases, followed by origin from the left circumflex artery, and origin from the left coronary artery with pooled prevalence of 22.1% (95%CI:15.0–26.2) and 2.7 (95%CI:0.7–5.2), respectively. A retrocaval course of the SANa was the most common course of the artery with a pooled prevalence of 47.1% (95%CI:36.0–55.5). The pooled prevalence of an S-shaped SANa was 7.6% (95%CI:2.9–14.1). Conclusions The SANa is most commonly reported as a single vessel, originating from the RCA, and taking a retrocaval course to reach the SAN. Knowledge of high risk anatomical variants of the SANa, such as an S-shaped artery, must be taken into account by surgeons to prevent iatrogenic injuries. Specifically, interventional or cardiosurgical procedures, such as the Cox maze procedure for atrial fibrillation, open heart surgeries through the right atrium or intraoperative cross-clamping or dissection procedures during mitral valve surgery using the septal

  4. Anatomical Variations of the Blood Vascular System in Veterinary Medicine. The Internal Iliac Artery of the Dog. Part Two.

    PubMed

    Avedillo, L; Martín-Alguacil, N; Salazar, I

    2016-04-01

    The aim of this study was to investigate the variability of the internal pudendal artery. Two hundred and thirty-two pelvic halves from 116 adult dogs were examined. Twenty-six anatomical variations were found, thirteen occurring in more than 5% of the dogs. Anatomical variations were grouped in relation to the origin of the prostatic/vaginal arteries, middle rectal artery, urethral artery, ventral perineal and caudal rectal arteries. The chi-squared test was used to analyse differences in sex, side of the body, profile and size, and the results were considered statistically significant when P ≤ 0.05. An identical vascular pattern in both hemipelvises was found for most of the anatomical variations described. PMID:25702925

  5. Aberrant Anatomical Variation of Maxillary Sinus Mimicking Periapical Cyst: A Report of Two Cases and Role of CBCT in Diagnosis

    PubMed Central

    Sekerci, Ahmet Ercan; Sisman, Yildiray; Etoz, Meryem; Bulut, Duygu Goller

    2013-01-01

    Most periapical lesions are associated with microorganisms from infected root canal systems. Maxillary sinus can pose a diagnostic dilemma radiographically because of its anatomical variation which can mimic a periapical pathosis. The aim of this study was to describe two cases of aberrant anatomical variation of the maxillary sinus that presented radiographic similarities to a periapical cyst in order to call the attention of clinicians to the fact that several different diseases are able to mimic endodontic periapical lesions. An accurate assessment of this morphology was made with the help of cone-beam computed tomography (CBCT). PMID:23710374

  6. Anatomical basis of variation in mesophyll resistance in eastern Australian sclerophylls: news of a long and winding path

    PubMed Central

    Tosens, Tiina

    2012-01-01

    In sclerophylls, photosynthesis is particularly strongly limited by mesophyll diffusion resistance from substomatal cavities to chloroplasts (r m), but the controls on diffusion limits by integral leaf variables such as leaf thickness, density, and dry mass per unit area and by the individual steps along the diffusion pathway are imperfectly understood. To gain insight into the determinants of r m in leaves with varying structure, the full CO2 physical diffusion pathway was analysed in 32 Australian species sampled from sites contrasting in soil nutrients and rainfall, and having leaf structures from mesophytic to strongly sclerophyllous. r m was estimated based on combined measurements of gas exchange and chlorophyll fluorescence. In addition, r m was modelled on the basis of detailed anatomical measurements to separate the importance of different serial resistances affecting CO2 diffusion into chloroplasts. The strongest sources of variation in r m were S c/S, the exposed surface area of chloroplasts per unit leaf area, and mesophyll cell wall thickness, t cw. The strong correlation of r m with t cw could not be explained by cell wall thickness alone, and most likely arose from a further effect of cell wall porosity. The CO2 drawdown from intercellular spaces to chloroplasts was positively correlated with t cw, suggesting enhanced diffusional limitations in leaves with thicker cell walls. Leaf thickness and density were poorly correlated with S c/S, indicating that widely varying combinations of leaf anatomical traits occur at given values of leaf integrated traits, and suggesting that detailed anatomical studies are needed to predict r m for any given species. PMID:22888123

  7. Anatomical Description and Clinical Relevance of a Rare Variation in the Mesenteric Arterial Arcade Pattern

    PubMed Central

    Hansdak, Ranjeeta; Thakur, Avinash; Mehta, Vandana; Rath, Gayatri

    2015-01-01

    Solitary vascular variations of the mesenteric arteries are extremely rare and have been seldom reported in the past. The aim of this study is to emphasize the anatomical and clinical relevance of one such rare variation of inferior mesenteric artery (IMA). The current case anomaly was incidentally observed while guiding the undergraduate medical students in the dissection of the mesenteric region of the abdomen in an Indian cadaver. An Accessory left colic artery was seen to be branching off from the Inferior Mesenteric artery and further dividing into two transverse branches which took part in the formation of arterial arc for the perfusion of the transverse and the descending colon. Awareness of such aberrant branches of Inferior Mesenteric artery helps in optimal selection of the mode of treatment or operative planning. Additionally, this knowledge minimizes possible iatrogenic injuries resulting from surgeries. Moreover, surgical anatomy of anomalous branches of Inferior Mesenteric artery is extremely essential for planning and successfully executing reconstructive procedures using these branches as pedicles for the transposed part of the colon. PMID:26435936

  8. Anatomic variations of the pelvic floor nerves adjacent to the sacrospinous ligament: a female cadaver study.

    PubMed

    Lazarou, George; Grigorescu, Bogdan A; Olson, Todd R; Downie, Sherry A; Powers, Kenneth; Mikhail, Magdy S

    2008-05-01

    Our objective was to document variations in the topography of pelvic floor nerves (PFN) and describe a nerve-free zone adjacent to the sacrospinous ligament (SSL). Pelvic floor dissections were performed on 15 female cadavers. The course of the PFN was described in relation to the ischial spine (IS) and the SSL. The pudendal nerve (PN) passed medial to the IS and posterior to the SSL at a mean distance of 0.6 cm (SD = +/-0.4) in 80% of cadavers. In 40% of cadavers, an inferior rectal nerve (IRN) variant pierced the SSL at a distance of 1.9 cm (SD = +/-0.7) medial to the IS. The levator ani nerve (LAN), coursed over the superior surface of the SSL-coccygeus muscle complex at a mean distance of 2.5 cm (SD = +/-0.7) medial to the IS. Anatomic variations were found which challenge the classic description of PFN. A nerve-free zone is situated in the medial third of the SSL. PMID:18038107

  9. Anatomical Variations of the Blood Vascular System in Veterinary Medicine: The Internal Iliac Artery of the Dog: Part One.

    PubMed

    Avedillo, L; Martín-Alguacil, N; Salazar, I

    2015-08-01

    Traditional veterinary anatomical models describe the branches of the caudal gluteal artery as the iliolumbar, cranial gluteal, lateral caudal, satellite of the ischiatic nerve and dorsal perineal arteries. However, some classical veterinary anatomy textbooks often indicate variations the general organization of the arterial tree, without giving any pattern of origin or illustrations of the different branching. The aim of this study was to investigate the presumptive variability of the caudal gluteal artery. Two hundred and thirty-two pelvic halves from 116 adult dogs were examined. Twelve anatomical variations were found, nine occurring in more than 5% of the dogs, and three in <5%. A 'long-type' internal iliac artery, which means short caudal gluteal and internal pudendal arteries, was identified, while a 'perineal trunk' was observed as an interesting arterial variation. If the caudal segment alone is taken into consideration, identical vascular patterns in both hemi-pelvises are found in 17% of the dogs. Significant statistical correlation was found for four different types of anatomic variations and gender, two types of variations and body size, one type of variation for body side and one type of variation for head shape. PMID:25196254

  10. Anatomical Study of the Ulnar Nerve Variations at High Humeral Level and Their Possible Clinical and Diagnostic Implications

    PubMed Central

    Guru, Anitha; Kumar, Naveen; Ravindra Shanthakumar, Swamy; Patil, Jyothsna; Nayak Badagabettu, Satheesha; Aithal Padur, Ashwini; Nelluri, Venu Madhav

    2015-01-01

    Background. Descriptive evaluation of nerve variations plays a pivotal role in the usefulness of clinical or surgical practice, as an anatomical variation often sets a risk of nerve palsy syndrome. Ulnar nerve (UN) is one amongst the major nerves involved in neuropathy. In the present anatomical study, variations related to ulnar nerve have been identified and its potential clinical implications discussed. Materials and Method. We examined 50 upper limb dissected specimens for possible ulnar nerve variations. Careful observation for any aberrant formation and/or communication in relation to UN has been carried out. Results. Four out of 50 limbs (8%) presented with variations related to ulnar nerve. Amongst them, in two cases abnormal communication with neighboring nerve was identified and variation in the formation of UN was noted in remaining two limbs. Conclusion. An unusual relation of UN with its neighboring nerves, thus muscles, and its aberrant formation might jeopardize the normal sensori-motor behavior. Knowledge about anatomical variations of the UN is therefore important for the clinicians in understanding the severity of ulnar nerve neuropathy related complications. PMID:26246909

  11. Anatomical Variations of the Transverse-Sigmoid Sinus Junction: Implications for Endovascular Treatment of Idiopathic Intracranial Hypertension.

    PubMed

    McCormick, Michael W; Bartels, Harrison G; Rodriguez, Analiz; Johnson, James E; Janjua, Rashid M

    2016-08-01

    Venous sinus pathology can result in multiple pathological diseases, including idiopathic intracranial hypertension (IIH). There remains a paucity of information on anatomical luminal variations of the major venous sinuses which may contribute to the etiology of certain disease states. Thirty-six transverse and sigmoid sinuses were removed following dissection of 19 unfixed cadaveric heads. Sinuses were opened longitudinally to study luminal variations. A semiquantitative classification system was developed to assess septations and blind pouches. Seventy-nine percent of cadavers had a luminal anatomical variation. Forty-four percent and 42% of sinuses dissected had occurrence of a septations or blind pouches, respectively. Thirty percent of septations and 25% of pouches were classified as large. Incidence of anatomical variations was not statistically significant between cadaver gender or sinus laterality. Luminal variations are present in the transverse and sigmoid sinuses at rates higher than expected. This study is the first to report the presence of blind pouches in the luminal wall of transverse and sigmoid sinuses. These variations can have clinical importance to the endovascular surgeon and may also contribute to the pathophysiological etiology of venous sinus diseases. Anat Rec, 299:1037-1042, 2016. © 2016 Wiley Periodicals, Inc. PMID:27161529

  12. ANATOMIC STUDY OF THE PROXIMAL THIRD OF THE FEMUR: FEMOROACETABULAR IMPACT AND THE CAM EFFECT

    PubMed Central

    Labronici, Pedro José; Alves, Sergio Delmonte; da Silva, Anselmo Fernandes; Giuberti, Gilberto Ribeiro; de Azevedo Neto, Justino Nóbrega; Mezzalira Penedo, Jorge Luiz

    2015-01-01

    To analyze anatomical variations of the proximal end of femur that could cause a femoroacetabular impact. Methods: 199 skeletically mature anatomical specimens of femurs were used. The femurs were measured in order to determine the anteversion angle of the femoral neck, neckshaft angle, sphericity of the femoral head at anteroposterior and superoinferior, angle between epiphysis and the anterior femoral neck, angle between epiphysis and the neck at lateral plane, anteroposterior distance at 5mm of the head and neck junction and anteroposterior distance of the neck base. Results: we found that the impact subgroup presented a significantly larger junction diameter of 5mm (p = 0.0001) and cam-head (%) (p= 0.0001), while base-cam (%) (p = 0.0001) showed a significantly smaller diameter than the subgroup without impact. It was identified that cam-head (%) ≤ 80 e base-cam (%) ≤ 73 were identified as the optimal impact points. Conclusion: our study showed that the effect cam, caused by anatomical variations of the proximal femoral end focused the head-neck junction and base of the neck-junction head-neck. These rates can be predictive factors of the impact. PMID:26998462

  13. Susceptibility-Weighted Imaging of the Anatomic Variation of Thalamostriate Vein and Its Tributaries

    PubMed Central

    Zhang, Xiao-fen; Li, Jian-ce; Wen, Xin-dong; Ren, Chuan-gen; Cai, Ming; Chen, Cheng-chun

    2015-01-01

    Background and Purpose Thalamostriate vein (TSV) is an important tributary of the internal cerebral vein, which mainly drains the basal ganglia and deep medulla. The purpose of this study was to explore the anatomic variation and quality of TSV and its smaller tributaries using susceptibility-weighted imaging (SWI). Methods We acquired SWI images in 40 volunteers on a 3.0T MR system using an 8-channel high-resolution phased array coil. The frequencies of the TSV and its tributaries were evaluated. We classified TSV into types I (forming a venous angle) and II (forming a false venous angle). We classified anterior caudate vein (ACV)into types 1 (1 trunk) and 2 (2 trunks) as well as into types A (joiningTSV), B (joining anterior septal vein), and C (joining the angle of both veins). Results The TSV drains the areas of caudate nucleus, internal capsule,lentiform nucleus, external capsule, claustrum, extreme capsule and the white matter of the frontoparietal lobes,except thalamus. The frequencies of the TSV, ACV and transverse caudate vein (ACV) were 92.5%, 87.5% and 63.8%, respectively. We found TSV types I and II in 79.7%, and 20.3% with significantly different constitution ratios (P< 0.05). The most common types of ACV were type 1 (90.0%) and type A (64.3%). Conclusion The complex three-dimensional (3D) venous architecture of TSV and its small tributaries manifests great variation, with significant and practical implications for neurosurgery. PMID:26506095

  14. Tendon of the long head of the biceps originating from the rotator cuff – An uncommon anatomical variation: case report☆

    PubMed Central

    Andreoli, Carlos Vicente; Esteves, Leonardo Roure; Figueiredo, Eduardo; Belangero, Paulo Santoro; de Castro Pochini, Alberto; Ejnisman, Benno

    2015-01-01

    Anatomical variations at the origin of the biceps tendon have been described by several authors, but occurrences of an origin in the supraspinatus are rare. It is unclear whether this variation might contribute toward pathological conditions of the shoulder. Our objective here was to describe a case of an anatomical variation in the origin of the tendon of the long head of the biceps. The clinical information, preoperative images and arthroscopic images relating to a patient with an aberrant origin of the long head of the biceps, which was observed during shoulder arthroscopy, were reviewed. In this case study, the origin of the biceps was found in the rotator cuff, without any origin from the supraglenoid tubercle or upper labrum. This variant did not seem to contribute toward the pathological condition of the shoulder, and standard treatment for the concomitant condition was sufficient for treating it. PMID:26962493

  15. Effects of Interfractional Motion and Anatomic Changes on Proton Therapy Dose Distribution in Lung Cancer

    SciTech Connect

    Hui Zhouguang; Zhang Xiaodong; Starkschall, George; Li Yupeng; Mohan, Radhe; Komaki, Ritsuko; Cox, James D.; Chang, Joe Y.

    2008-12-01

    Purpose: Proton doses are sensitive to intra- and interfractional anatomic changes. We analyzed the effects of interfractional anatomic changes in doses to lung tumors treated with proton therapy. Methods and Materials: Weekly four-dimensional computed tomography (4D-CT) scans were acquired for 8 patients with mobile Stage III non-small cell lung cancer who were actually treated with intensity-modulated photon radiotherapy. A conformal proton therapy passive scattering plan was designed for each patient. Dose distributions were recalculated at end-inspiration and end-expiration breathing phases on each weekly 4D-CT data set using the same plans with alignment based on bone registration. Results: Clinical target volume (CTV) coverage was compromised (from 99% to 90.9%) in 1 patient because of anatomic changes and motion pattern variation. For the rest of the patients, the mean CTV coverage on the repeated weekly 4D-CT data sets was 98.4%, compared with 99% for the original plans. For all 8 patients, however, a mean 4% increase in the volume of the contralateral lung receiving a dose of at least 5 Gy (V5) and a mean 4.4-Gy increase in the spinal cord maximum dose was observed in the repeated 4D-CT data sets. A strong correlation between the CTV density change resulting from tumor shrinkage or anatomic variations and mean contralateral lung dose was observed. Conclusions: Adaptive re-planning during proton therapy may be indicated in selected patients with non-small cell lung cancer. For most patients, however, CTV coverage is adequate if tumor motion is taken into consideration in the original simulation and planning processes.

  16. An ``Anatomic approach" to study the Casimir effect

    NASA Astrophysics Data System (ADS)

    Intravaia, Francesco; Haakh, Harald; Henkel, Carsten

    2010-03-01

    The Casimir effect, in its simplest definition, is a quantum mechanical force between two objects placed in vacuum. In recent years the Casimir force has been the object of an exponentially growing attention both from theorists and experimentalists. A new generation of experiments paved the way for new challenges and spotted some shadows in the comparison to theory. Here we are going to isolate different contributions to the Casimir interaction and perform a detailed study to shine new light on this phenomenon. As an example, the contributions of Foucault (eddy current) modes will be discussed in different configurations. This ``anatomic approach'' allows to clearly put into evidence special features and to explain unusual behaviors. This brings new physical understanding on the undergoing physical mechanisms and suggests new ways to engineer the Casimir effect.

  17. Coronary anatomy, anatomic variations and anomalies: a retrospective coronary angiography study

    PubMed Central

    Altin, Cihan; Kanyilmaz, Suleyman; Koc, Sahbender; Gursoy, Yusuf Cemil; Bal, Uğur; Aydinalp, Alp; Yildirir, Aylin; Muderrisoglu, Haldun

    2015-01-01

    INTRODUCTION The incidence of coronary artery anomalies (CAAs) varies from 0.2% to 8.4%. Knowledge of such anatomical variations is important as coronary procedures are regularly performed these days. We aimed to find the coronary dominance pattern, intermediate artery (IMA) frequency and CAA incidence in our clinic, and compare them to those in the literature. METHODS The medical reports of 5,548 patients who had undergone coronary angiography (CAG) between 2005 and 2009 were retrospectively investigated. Dominance pattern and presence of IMA and CAA were recorded. CAAs were described using two different classifications: Angelini and Khatami’s classification, and a new modified classification that was derived from Angelini and Khatami’s classification. Some procedural details and clinical features of the patients with CAA were also investigated. RESULTS Coronary dominance pattern was: 81.6% right coronary artery, 12.2% circumflex artery and 6.2% co-dominant. IMA was present in 613 (11.0%) patients. The incidences of overall anomaly were 2.7% and 1.4%, according to the different classifications. Absent left main coronary artery, which was the most common anomaly in the present study, was found in 51 (0.9%) patients. Incidences of myocardial bridge, coronary arteriovenous fistulae and aneurysms were 1.1%, 0.2% and 0.3%, respectively. CONCLUSION CAAs are generally asymptomatic, isolated lesions. Some may lead to anginal symptoms, myocardial infarction or sudden death. We found that CAA was associated with increased radiation and contrast exposure in patients who underwent CAG. This risk could be reduced if appropriate catheters were designed and training programmes on ostial cannulation were developed. PMID:25502334

  18. Anatomical variation of superior petrosal vein and its management during surgery for cerebellopontine angle meningiomas.

    PubMed

    Watanabe, Takao; Igarashi, Takahiro; Fukushima, Takao; Yoshino, Atsuo; Katayama, Yoichi

    2013-10-01

    No systematic study is yet available that focuses on the surgical anatomy of the superior petrosal vein and its significance during surgery for cerebellopontine angle meningiomas. The aim of the present study was to examine the variation of the superior petrosal vein via the retrosigmoid suboccipital approach in relation to the tumor attachment of cerebellopontine angle meningiomas as well as postoperative complications related to venous occlusion. Forty-three patients with cerebellopontine angle meningiomas were analyzed retrospectively. Based on the operative findings, the tumors were classified into four subtypes: the petroclival type, tentorial type, anterior petrous type, and posterior petrous type. According to a previous anatomical report, the superior petrosal veins were divided into three groups: Type I which emptied into the superior petrosal sinus above and lateral to the internal acoustic meatus, Type II which emptied between the lateral limit of the trigeminal nerve at Meckel's cave and the medial limit of the facial nerve at the internal acoustic meatus, and Type III which emptied into the superior petrosal sinus above and medial to Meckel's cave. In both the petroclival and anterior petrous types, the most common vein was Type III which is the ideal vein for a retrosigmoid approach. In contrast, the Type II vein which is at high risk of being sacrificed during a suprameatal approach procedure was most frequent in posterior petrous type, in which the superior petrosal vein was not largely an obstacle. Intraoperative sacrificing of veins was associated with a significantly higher rate of venous-related phenomena, while venous complications occurred even in cases where the superior petrosal vein was absent or compressed by the tumor. The variation in the superior petrosal vein appeared to differ among the tumor attachment subtypes, which could permit a satisfactory surgical exposure without dividing the superior petrosal vein. In cases where the

  19. Anatomical Variations of the Blood Vascular System in Veterinary Medicine: The Internal Iliac Artery of the Dog - Part Three.

    PubMed

    Avedillo, L; Martín-Alguacil, N; Salazar, I

    2016-06-01

    The aim of this study was to analyse and describe the variability of the umbilical artery. Two hundred and thirty-two pelvic halves from 116 adult dogs were examined. To study the permeability of the umbilical artery, ten adult dogs, nine newborns and thirteen foetuses between 35 and 50 days of gestation were also used. In relation to the origin of the umbilical artery, six anatomical variations were found. From which five involved a cranial (n = 4) or caudal (n = 1) relocation of its origin, and in one case (n = 1), the umbilical artery arose from the median sacral artery. In eight cases, the umbilical artery gave off the prostatic (n = 1) or vaginal (n = 7) arteries. The permeability of the umbilical artery was the most significant anatomical variation: permeability was detected in 45% (106 of 232 pelvic halves) of all cases, from which 36 were males and 70 females. Interestingly, an equal vascular permeability in both hemipelvises was found for 82% of the dogs, thus additional data related to such feature of the umbilical artery was also recorded. In accordance with the statistical study, the main anatomical variations described showed significant values for gender, side of the body, size and profile variables. PMID:26183610

  20. The evolution of the anatomically modern or advanced Homo sapiens: time, place, process, affinities and variations.

    PubMed

    Raghavan, P; Pathmanathan, G; Talwar, I

    2009-06-01

    This paper surveys the opinions expressed in the recent literature on the origins of the anatomically- modern Homo sapiens, and reviews the evidence from cranial and dental morphology argued by proponents of opposing views to support their case. It also critically analyses problems facing the interpretation of the evidence in arriving at a definitive conclusion to the debate. PMID:19551306

  1. Abductor Hallucis: Anatomical Variation and Its Clinical Implications in the Reconstruction of Chronic Nonhealing Ulcers and Defects of Foot

    PubMed Central

    Chittoria, Ravi Kumar; Pratap, Harsha; Yekappa, Suma Hottigoudar

    2015-01-01

    Abductor hallucis (AH) is an intrinsic muscle of sole of the foot. It is commonly used in the coverage of ankle and heel defects and chronic nonhealing ulcers of the foot; its use is reported to have a favorable long-term outcome. The muscle's apt bulk and size, its simple surgical isolation, absence of donor-site defect, unvaried anatomy, and long neurovascular pedicle are some of the advantages that make it a promising muscle flap. During routine cadaver dissection in the Department of Anatomy of Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Pondicherry, India, we identified an anatomical variation in AH in both feet of a 45-year-old embalmed male Indian cadaver. The variant muscle had innumerable proximal attachments, a majority of them arising atypically in the form of tough tendinous slips from the medial intermuscular septum at the junction of central and tibial components of plantar aponeurosis, the medial surface of first metatarsal and the intermuscular septum separating AH from the flexor hallucis brevis. The tendon: muscle ratio was 1.76, higher than the normal reported ratio of 0.56±0.07. This article highlights the variation noted and its implication for clinicians. On Internet search, we did not come across the variations described in our article. Findings of the anatomical variation reported in this article could benefit surgeons who decide to use AH flaps in the future. PMID:26634184

  2. Anatomical variations and pre-operative imaging technique concerning the anterolateral thigh flap: guiding the surgeon.

    PubMed

    De Beule, Tom; Van Deun, Wouter; Vranckx, Jan; de Dobbelaere, Bart; Maleux, Geert; Heye, Sam

    2016-07-01

    The anterolateral thigh (ALT) flap has widespread use throughout the body because of the many engineering options. The ALT has a complex local vasculature, which can be of importance for the surgical approach. In general, the flap receives its perfusion from branches of the lateral circumflex femoral artery (LCFA). The LCFA, however, has a large anatomic variance. CT angiography can guide the surgeon in the selection of the most suitable site and aid in the surgical approach. PMID:27150071

  3. Effect of anatomical variability on electric field characteristics of electroconvulsive therapy and magnetic seizure therapy: a parametric modeling study.

    PubMed

    Deng, Zhi-De; Lisanby, Sarah H; Peterchev, Angel V

    2015-01-01

    Electroconvulsive therapy (ECT) and magnetic seizure therapy (MST) are conventionally applied with a fixed stimulus current amplitude, which may result in differences in the neural stimulation strength and focality across patients due to interindividual anatomical variability. The objective of this study is to quantify the effect of head anatomical variability associated with age, sex, and individual differences on the induced electric field characteristics in ECT and MST. Six stimulation modalities were modeled including bilateral and right unilateral ECT, focal electrically administered seizure therapy (FEAST), and MST with circular, cap, and double-cone coils. The electric field was computed using the finite element method in a parameterized spherical head model representing the variability in the general population. Head tissue layer thicknesses and conductivities were varied to examine the impact of interindividual anatomical differences on the stimulation strength, depth, and focality. Skull conductivity most strongly affects the ECT electric field, whereas the MST electric field is independent of tissue conductivity variation in this model but is markedly affected by differences in head diameter. Focal ECT electrode configurations such as FEAST is more sensitive to anatomical variability than that of less focal paradigms such as BL ECT. In MST, anatomical variability has stronger influence on the electric field of the cap and circular coils compared to the double-cone coil, possibly due to the more superficial field of the former. The variability of the ECT and MST electric fields due to anatomical differences should be considered in the interpretation of existing studies and in efforts to improve dosing approaches for better control of stimulation strength and focality across patients, such as individualization of the current amplitude. The conventional approach to individualizing dosage by titrating the number of pulses cannot compensate for differences in

  4. Effect of anatomical variability on electric field characteristics of electroconvulsive therapy and magnetic seizure therapy: a parametric modeling study

    PubMed Central

    Deng, Zhi-De; Lisanby, Sarah H.; Peterchev, Angel V.

    2014-01-01

    Electroconvulsive therapy (ECT) and magnetic seizure therapy (MST) are conventionally applied with a fixed stimulus current amplitude, which may result in differences in the neural stimulation strength and focality across patients due to interindividual anatomical variability. The objective of this study is to quantify the effect of head anatomical variability associated with age, sex, and individual differences on the induced electric field characteristics in ECT and MST. Six stimulation modalities were modeled including bilateral and right unilateral ECT, focal electrically administered seizure therapy (FEAST), and MST with circular, cap, and double-cone coils. The electric field was computed using the finite element method in a parameterized spherical head model representing the variability in the general population. Head tissue layer thicknesses and conductivities were varied to examine the impact of interindividual anatomical differences on the stimulation strength, depth, and focality. Skull conductivity most strongly affects the ECT electric field, whereas the MST electric field is independent of tissue conductivity variation in this model but is markedly affected by differences in head diameter. Focal ECT electrode configurations such as FEAST is more sensitive to anatomical variability than that of less focal paradigms such as BL ECT. In MST, anatomical variability has stronger influence on the electric field of the cap and circular coils compared to the double-cone coil, possibly due to the more superficial field of the former. The variability of the ECT and MST electric field due to anatomical differences should be considered in the interpretation of existing studies and in efforts to improve dosing approaches for better control of stimulation strength and focality across patients, such as individualization of the current amplitude. The conventional approach to individualizing dosage by titrating the number of pulses cannot compensate for differences in

  5. Palmaris Longus Muscle’s Prevalence in Different Nations and Interesting Anatomical Variations: Review of the Literature

    PubMed Central

    Ioannis, Dimitriou; Anastasios, Katsourakis; Konstantinos, Natsis; Lazaros, Kostretzis; Georgios, Noussios

    2015-01-01

    The prevalence of the palmaris longus (PL) muscle varies more than any other muscle in the human body. Its absence across the world ranges between 1.5% and 63.9%. It presents with many different anomalies, discovered either clinically, intraoperatively or after anatomical examination of cadavers. This paper includes recent studies and reports about the presence and variations of the PL muscle, thereby illustrating the differences between ethnic groups, as well as emphasizing the different ways of finding it, during daily clinical and surgical practice. PMID:26491493

  6. Broad Anatomical Variation within a Narrow Wood Density Range—A Study of Twig Wood across 69 Australian Angiosperms

    PubMed Central

    Ziemińska, Kasia; Westoby, Mark; Wright, Ian J.

    2015-01-01

    Objectives Just as people with the same weight can have different body builds, woods with the same wood density can have different anatomies. Here, our aim was to assess the magnitude of anatomical variation within a restricted range of wood density and explore its potential ecological implications. Methods Twig wood of 69 angiosperm tree and shrub species was analyzed. Species were selected so that wood density varied within a relatively narrow range (0.38–0.62 g cm-3). Anatomical traits quantified included wood tissue fractions (fibres, axial parenchyma, ray parenchyma, vessels, and conduits with maximum lumen diameter below 15 μm), vessel properties, and pith area. To search for potential ecological correlates of anatomical variation the species were sampled across rainfall and temperature contrasts, and several other ecologically-relevant traits were measured (plant height, leaf area to sapwood area ratio, and modulus of elasticity). Results Despite the limited range in wood density, substantial anatomical variation was observed. Total parenchyma fraction varied from 0.12 to 0.66 and fibre fraction from 0.20 to 0.74, and these two traits were strongly inversely correlated (r = -0.86, P < 0.001). Parenchyma was weakly (0.24 ≤|r|≤ 0.35, P < 0.05) or not associated with vessel properties nor with height, leaf area to sapwood area ratio, and modulus of elasticity (0.24 ≤|r|≤ 0.41, P < 0.05). However, vessel traits were fairly well correlated with height and leaf area to sapwood area ratio (0.47 ≤|r|≤ 0.65, all P < 0.001). Modulus of elasticity was mainly driven by fibre wall plus vessel wall fraction rather than by the parenchyma component. Conclusions Overall, there seem to be at least three axes of variation in xylem, substantially independent of each other: a wood density spectrum, a fibre-parenchyma spectrum, and a vessel area spectrum. The fibre-parenchyma spectrum does not yet have any clear or convincing ecological interpretation. PMID

  7. Rare Anatomical Variation of Dual IVC with Left Sided IVC Draining into Hemiazygous Vein- A Case Report

    PubMed Central

    Modi, Pranjal; Sutariya, Harsh; Patel, Kajal

    2016-01-01

    Congenital anomalies of the Inferior Vena Cava (IVC) result from the persistence of the embryonic venous system. Knowledge of such anomaly is of great importance during abdominal surgery, liver and kidney transplantation, renal venous sampling and in the treatment of thromboembolic diseases. Here, we report a rare anatomical variation of dual IVC with normal course of right sided IVC and hemiazygous continuation of left sided IVC with interiliac communication in potential renal donor. Congenital abnormalities of the inferior vena cava are easily identified on Computed Tomography (CT) and should be considered when interpreting any CT of the abdomen or chest. PMID:27134969

  8. Rare Anatomical Variation of Dual IVC with Left Sided IVC Draining into Hemiazygous Vein- A Case Report.

    PubMed

    Gandhi, Shruti P; Modi, Pranjal; Sutariya, Harsh; Patel, Kajal

    2016-03-01

    Congenital anomalies of the Inferior Vena Cava (IVC) result from the persistence of the embryonic venous system. Knowledge of such anomaly is of great importance during abdominal surgery, liver and kidney transplantation, renal venous sampling and in the treatment of thromboembolic diseases. Here, we report a rare anatomical variation of dual IVC with normal course of right sided IVC and hemiazygous continuation of left sided IVC with interiliac communication in potential renal donor. Congenital abnormalities of the inferior vena cava are easily identified on Computed Tomography (CT) and should be considered when interpreting any CT of the abdomen or chest. PMID:27134969

  9. Effect of anatomical backgrounds on detectability in volumetric cone beam CT images

    NASA Astrophysics Data System (ADS)

    Han, Minah; Park, Subok; Baek, Jongduk

    2016-03-01

    As anatomical noise is often a dominating factor affecting signal detection in medical imaging, we investigate the effects of anatomical backgrounds on signal detection in volumetric cone beam CT images. Signal detection performances are compared between transverse and longitudinal planes with either uniform or anatomical backgrounds. Sphere objects with diameters of 1mm, 5mm, 8mm, and 11mm are used as the signals. Three-dimensional (3D) anatomical backgrounds are generated using an anatomical noise power spectrum, 1/fβ, with β=3, equivalent to mammographic background [1]. The mean voxel value of the 3D anatomical backgrounds is used as an attenuation coefficient of the uniform background. Noisy projection data are acquired by the forward projection of the uniform and anatomical 3D backgrounds with/without sphere lesions and by the addition of quantum noise. Then, images are reconstructed by an FDK algorithm [2]. For each signal size, signal detection performances in transverse and longitudinal planes are measured by calculating the task SNR of a channelized Hotelling observer with Laguerre-Gauss channels. In the uniform background case, transverse planes yield higher task SNR values for all sphere diameters but 1mm. In the anatomical background case, longitudinal planes yield higher task SNR values for all signal diameters. The results indicate that it is beneficial to use longitudinal planes to detect spherical signals in anatomical backgrounds.

  10. Rare anatomical variations of persistent trigeminal artery in two patients with non-aneurysmal subarachnoid hemorrhage.

    PubMed

    Samaniego, Edgar A; Dabus, Guilherme; Andreone, Vincenzo; Linfante, Italo

    2011-09-01

    Carotid-basilar anastomoses are remnants of the fetal circulation and although rare, they may become symptomatic and should be recognized during cerebral angiography. Two patients are described with non-aneurysmal subarachnoid hemorrhage and persistent trigeminal arteries (PTA) found on cerebral angiography. In the first patient, the PTA ended in the anterior inferior cerebellar artery (AICA) and posterior inferior cerebellar artery. The second patient had a PTA terminating in the AICA and superior cerebellar artery. These rare anatomical PTA variants should be recognized on cerebral angiography. PMID:21990842

  11. Inadvertent Dural Puncture during Caudal Approach by the Introducer Needle for Epidural Adhesiolysis Caused by Anatomical Variation

    PubMed Central

    Kim, Si Gon; Kim, Do Wan; Lee, Yeon Ju

    2013-01-01

    There have been reports of abnormalities in the lumbosacral region involving a lower-than-normal termination of the dural sac, which is caused by disease or anatomical variation. Inadvertent dural puncture or other unexpected complications can occur during caudal epidural block or adhesiolysis in patients with these variations, but only a small number of case reports have described this issue. We report a case of dural puncture by the introducer needle before attempting caudal epidural adhesiolysis, which occurred even though the needle was not advanced upward after penetrating the sacrococcygeal ligament. Dural puncture was caused by a morphological abnormality in the lumbosacral region, with no pathological condition; the dural sac terminal was located more distally than normal. However, dural puncture could have been prevented if we had checked for such an abnormality in the magnetic resonance imaging (MRI) taken before the procedure. PMID:23614088

  12. The Prevalence of Anatomical Variations of the Median Nerve in the Carpal Tunnel: A Systematic Review and Meta-Analysis

    PubMed Central

    Roy, Joyeeta; Vikse, Jens; Ramakrishnan, Piravin Kumar; Walocha, Jerzy A.; Tomaszewski, Krzysztof A.

    2015-01-01

    Background and Objective The course and branches of the median nerve (MN) in the wrist vary widely among the population. Due to significant differences in the reported prevalence of such variations, extensive knowledge on the anatomy of the MN is essential to avoid iatrogenic nerve injury. Our aim was to determine the prevalence rates of anatomical variations of the MN in the carpal tunnel and the most common course patterns and variations in its thenar motor branch (TMB). Study Design A systematic search of all major databases was performed to identify articles that studied the prevalence of MN variations in the carpal tunnel and the TMB. No date or language restrictions were set. Extracted data was classified according to Lanz's classification system: variations in the course of the single TMB—extraligamentous, subligamentous, and transligamentous (type 1); accessory branches of the MN at the distal carpal tunnel (type 2); high division of the MN (type 3); and the MN and its accessory branches proximal to the carpal tunnel (type 4). Pooled prevalence rates were calculated using MetaXL 2.0. Results Thirty-one studies (n = 3918 hands) were included in the meta-analysis. The pooled prevalence rates of the extraligamentous, subligamentous, and transligamentous courses were 75.2% (95%CI:55.4%-84.7%), 13.5% (95%CI:3.6%-25.7%), and 11.3% (95%CI:2.4%-23.0%), respectively. The prevalence of Lanz group 2, 3, and 4 were 4.6% (95%CI:1.6%-9.1%), 2.6% (95%CI:0.1%-2.8%), and 2.3% (95%CI:0.3%-5.6%), respectively. Ulnar side of branching of the TMB was found in 2.1% (95%CI:0.9%-3.6%) of hands. The prevalence of hypertrophic thenar muscles over the transverse carpal ligament was 18.2% (95%CI:6.8%-33.0%). A transligamentous course of the TMB was more commonly found in hands with hypertrophic thenar muscles (23.4%, 95%CI:5.0%-43.4%) compared to those without hypertrophic musculature (1.7%, 95%CI:0%-100%). In four studies (n = 423 hands), identical bilateral course of the TMB was

  13. SEM characterization of anatomical variation in chitin organization in insect and arthropod cuticles.

    PubMed

    Chandran, Rakkiyappan; Williams, Lee; Hung, Albert; Nowlin, Kyle; LaJeunesse, Dennis

    2016-03-01

    The cuticles of insects and arthropods have some of the most diverse material properties observed in nature, so much so that it is difficult to imagine that all cutciles are primarily composed of the same two materials: a fibrous chitin network and a matrix composed of cuticle proteins. Various factors contribute to the mechanical and optical properties of an insect or arthropod cuticle including the thickness and composition. In this paper, we also identified another factor that may contribute to the optical, surface, and mechanical properties of a cuticle, i.e. the organization of chitin nanofibers and chitin fiber bundles. Self-assembled chitin nanofibers serve as the foundation for all higher order chitin structures in the cuticles of insects and other arthropods via interactions with structural cuticle proteins. Using a technique that enables the characterization of chitin organization in the cuticle of intact insects and arthropod exoskeletons, we demonstrate a structure/function correlation of chitin organization with larger scale anatomical structures. The chitin scaffolds in cuticles display an extraordinarily diverse set of morphologies that may reflect specific mechanical or physical properties. After removal of the proteinaceous and mineral matrix of a cuticle, we observe using SEM diverse nanoscale and micro scale organization of in-situ chitin in the wing, head, eye, leg, and dorsal and ventral thoracic regions of the periodical cicada Magicicada septendecim and in other insects and arthropods. The organization of chitin also appears to have a significant role in the organization of nanoscale surface structures. While microscale bristles and hairs have long been known to be chitin based materials formed as cellular extensions, we have found a nanostructured layer of chitin in the cuticle of the wing of the dog day annual cicada Tibicen tibicens, which may be the scaffold for the nanocone arrays found on the wing. We also use this process to examine

  14. Racial Variations in Prostate Cancer Molecular Subtypes and Androgen Receptor Signaling Reflect Anatomic Tumor Location

    PubMed Central

    Faisal, Farzana A.; Sundi, Debasish; Tosoian, Jeffrey J.; Choeurng, Voleak; Alshalalfa, Mohammed; Ross, Ashley E.; Klein, Eric; Den, Robert; Dicker, Adam; Erho, Nicholas; Davicioni, Elai; Lotan, Tamara L.; Schaeffer, Edward M.

    2016-01-01

    Prostate cancer (PCa) subtypes based on ETS gene expression have been described. Recent studies suggest there are racial differences in tumor location, with PCa located anteriorly more often among African-American (AA) compared to Caucasian-American (CA) men. In this retrospective analysis of a multi-institutional cohort treated by radical prostatectomy (179 CA, 121 AA), we evaluated associations among molecular subtype, race, anatomic tumor location, and androgen receptor (AR) signaling. Subtype (m-ERG+, m-ETS+, m-SPINK1+, or triple-negative) was determined using distribution-based outlier analysis. AR signaling was investigated using gene expression profiling of canonical AR targets. m-ERG+ was more common in CA than AA men (47% vs 22%, p < 0.001). AA men were more likely to be m-SPINK1+ (13% vs 7%; p = 0.069) and triple-negative (50% vs 37%; p = 0.043). Racial differences in molecular subtypes did not persist when tumors were analyzed by location, suggesting a biologically important relationship between tumor location and subtype. Accordingly, anterior tumor location was associated with higher Decipher scores and lower global AR signaling. Patient summary This study demonstrates associations among patient race, prostate cancer molecular subtypes, and tumor location. Location-specific differences in androgen regulation may further underlie these relationships. PMID:26443432

  15. Intraspecific Variation in Wood Anatomical, Hydraulic, and Foliar Traits in Ten European Beech Provenances Differing in Growth Yield.

    PubMed

    Hajek, Peter; Kurjak, Daniel; von Wühlisch, Georg; Delzon, Sylvain; Schuldt, Bernhard

    2016-01-01

    In angiosperms, many studies have described the inter-specific variability of hydraulic-related traits and little is known at the intra-specific level. This information is however mandatory to assess the adaptive capacities of tree populations in the context of increasing drought frequency and severity. Ten 20-year old European beech (Fagus sylvatica L.) provenances representing the entire distribution range throughout Europe and differing significantly in aboveground biomass increment (ABI) by a factor of up to four were investigated for branch wood anatomical, hydraulic, and foliar traits in a provenance trial located in Northern Europe. We quantified to which extend xylem hydraulic and leaf traits are under genetic control and tested whether the xylem hydraulic properties (hydraulic efficiency and safety) trades off with yield and wood anatomical and leaf traits. Our results showed that only three out of 22 investigated ecophysiological traits showed significant genetic differentiations between provenances, namely vessel density (VD), the xylem pressure causing 88% loss of hydraulic conductance and mean leaf size. Depending of the ecophysiological traits measured, genetic differentiation between populations explained 0-14% of total phenotypic variation, while intra-population variability was higher than inter-population variability. Most wood anatomical traits and some foliar traits were additionally related to the climate of provenance origin. The lumen to sapwood area ratio, vessel diameter, theoretical specific conductivity and theoretical leaf-specific conductivity as well as the C:N-ratio increased with climatic aridity at the place of origin while the carbon isotope signature (δ(13)C) decreased. Contrary to our assumption, none of the wood anatomical traits were related to embolism resistance but were strong determinants of hydraulic efficiency. Although ABI was associated with both VD and δ(13)C, both hydraulic efficiency and embolism resistance were

  16. Intraspecific Variation in Wood Anatomical, Hydraulic, and Foliar Traits in Ten European Beech Provenances Differing in Growth Yield

    PubMed Central

    Hajek, Peter; Kurjak, Daniel; von Wühlisch, Georg; Delzon, Sylvain; Schuldt, Bernhard

    2016-01-01

    In angiosperms, many studies have described the inter-specific variability of hydraulic-related traits and little is known at the intra-specific level. This information is however mandatory to assess the adaptive capacities of tree populations in the context of increasing drought frequency and severity. Ten 20-year old European beech (Fagus sylvatica L.) provenances representing the entire distribution range throughout Europe and differing significantly in aboveground biomass increment (ABI) by a factor of up to four were investigated for branch wood anatomical, hydraulic, and foliar traits in a provenance trial located in Northern Europe. We quantified to which extend xylem hydraulic and leaf traits are under genetic control and tested whether the xylem hydraulic properties (hydraulic efficiency and safety) trades off with yield and wood anatomical and leaf traits. Our results showed that only three out of 22 investigated ecophysiological traits showed significant genetic differentiations between provenances, namely vessel density (VD), the xylem pressure causing 88% loss of hydraulic conductance and mean leaf size. Depending of the ecophysiological traits measured, genetic differentiation between populations explained 0–14% of total phenotypic variation, while intra-population variability was higher than inter-population variability. Most wood anatomical traits and some foliar traits were additionally related to the climate of provenance origin. The lumen to sapwood area ratio, vessel diameter, theoretical specific conductivity and theoretical leaf-specific conductivity as well as the C:N-ratio increased with climatic aridity at the place of origin while the carbon isotope signature (δ13C) decreased. Contrary to our assumption, none of the wood anatomical traits were related to embolism resistance but were strong determinants of hydraulic efficiency. Although ABI was associated with both VD and δ13C, both hydraulic efficiency and embolism resistance were

  17. Assessment and Evaluation of Anatomic Variations of Retromolar Pad: A Cross Sectional Study

    PubMed Central

    Deep, Anchal; Siwach, Amit; Singh, Manas; Bhargava, Akshay; Siwach, Reenu

    2016-01-01

    Introduction The retromolar pad also called piriformis papilla is a mucosal elevation located in the retromolar area covering the retromolar triangle. After molar loss, the bony alveolar process and surrounding soft periodontal tissue remodel, mainly resorb and blend with retromolar pad. It is a key intraoral landmark in prosthodontics. Aim The aim of this in-vitro study was to analyze the various anatomical shapes and sizes of retromolar pad in 150 completely edentulous patients between 55 to 70 years of age group. Materials and Methods The study was conducted on 150 completely edentulous patients. The shapes of retromolar pad on the left and right side were seen and divided into pear, triangular and round shape. The comparison of the mean longitudinal diameter and transverse diameter on the right and left sides was done. The data was evaluated statistically. The chi-square test was used for the comparison between the proportions with the help of standard deviation, t-test was used for comparison between the left and the right side and ANOVA test was used for comparison between the various shapes of the retromolar pads. Results The result showed that there was statistically significant difference among different shapes of retromolar pad and there was significant difference in mean transverse and longitudinal diameter on right and left side, the mean value of the longitudinal diameter on left and right side was 8.81 and 8.69 whereas the mean value of the transverse diameter on left and right side was 6.79 and 6.82 respectively and p-value obtained for both was 0.550 and 0.814 respectively. Conclusion The study conclude that there are three different shapes of retromolar pad among which pear and triangular shaped retomolar pad provides more stability in lower denture because of increase surface area. PMID:27437350

  18. Evaluation of anatomical variation of the crista galli using computed tomography.

    PubMed

    Hajiioannou, Jiannis; Owens, David; Whittet, Heikki B

    2010-05-01

    Pneumatization of the crista galli is a recognized incidental finding on computed tomography (CT), usually with little relevance to the clinical picture. There are, however, notable exceptions: congenital midline nasal defects including nasal dermoids have been seen to track through or near the crista galli. Mucocele development has also been seen. This study aimed to evaluate the variation in crista galli morphology and pneumatization and assess whether specific morphologies occur. A retrospective observational study was undertaken between November 2007 and January 2008. Using coronal and axial reconstructed CT views, images of the head in the region of the paranasal sinuses were assessed. Variations in the crista galli were classified according to their position relative to the cribriform plate and to the degree of pneumatization. Computed tomography findings of the morphology of the crista galli in 99 patients were reviewed and a classification system derived from the findings. Three variations of the position of the base of the crista galli were defined. In 28.3% of subjects the base of the crista galli did not extend below the level of the cribriform plate. In 63.6%, the crista galli extended less than 50% of its height below the cribriform plate and in 8.1% of the scans the crista galli extended more than 50% of its height below the cribriform plate. Pneumatization was noticed in 14.1% of the scans. Our results demonstrate the variation that occurs in the morphology and pneumatization of the crista galli. We hope this knowledge might be of help in preoperative planning of surgical approaches to sites of disease involving the crista galli. PMID:20196125

  19. A rare anatomical variation: a case of a common celiacomesenteric trunk in a cat.

    PubMed

    Gorissen, B M C; Moens, H C; Wolschrijn, C F

    2014-08-01

    In this study, we present a cat with a common 1-cm-long celiacomesenteric trunk. The arteria hepatica branched off first from the separate arteria celiaca and gave rise to the arteria gastrica dextra and arteria gastroduodenalis. The main stem of the arteria celiaca then split into the arteria gastrica sinistra and the arteria lienalis. The arteria mesenterica cranialis extended ventrocaudally in the mesentery. This variation is due to developmental changes in the ventral splanchnic arteries, and they are quite varied. The basic architecture and perfused organs are comparable, which indicates that the presence of a common celiacomesenteric trunk is more related to individual development than to phylogeny or function. PMID:23713949

  20. Anatomic variations of the root canal of the rat according to age.

    PubMed

    Gómez, Paula A; Cabrini, Rómulo L

    2004-01-01

    The mesial canal of the first lower molar of the rat has been used as an experimental model in Endodontics. The present study involves a detailed analysis of its structural variations as a function of age and thus contributes to its characterization and adequate use as an experimental model. We evaluated 60 molars of Wistar rats of different body weight: (group 1: 300-399 g, n=22; group 2: 400-499 g, n=16; group 3: 600-700 g, n=22). The samples were radiographed employing a standardized system. Total canal length and volume were measured on enlarged projections of the radiographs. Canal diameter was measured at coronary, middle and apical levels and employed to estimate the area of canal cross-section as an indicator of potential flow or metabolic interchange. From the second age group onwards, we detected radicular hypercementosis that increased canal length and resulted in the formation of a complex apical delta. The canal diameter decreased very significantly in the apical third. The estimated flow expressed in terms of the area of cross-section on the projection decreased from 1.2 mm2 in Group 1 to 0.05 mm2 in Group 2. Group 3 did not differ significantly from Group 2. The present results reveal that the spontaneous, age-related variations in canal anatomy described herein must be considered when performing experimental endodontics in rats. PMID:15584260

  1. Fusiform aneurysm of a persistent primitive trigeminal artery associated with cerebrovascular anatomic variations: a report of two cases.

    PubMed

    Pleş, Horia; Loukas, Marios; Andall, Rebecca G; Andall, Naomi R; Iacob, Nicoleta; Miclăuş, GraŢian Dragoslav; Matusz, Petru; Tubbs, R Shane

    2015-01-01

    There are four embryonic anastomoses that exist between the internal carotid artery (ICA) and the vertebrobasilar (VB) system, which may fail to regress postfetal life; one of which is the trigeminal artery. Other persistent anastomoses include those formed by the hypoglossal, otic and proatlantic intersegmental arteries. In addition, other cerebrovascular variations may accompany a persistent primitive trigeminal artery (PPTA); such as arteriovenous malformations, aneurysms, carotid-cavernous fistulas and stenotic cerebral vessels. We present two very rare cases of a left PPTA. In the first case, there was a past medical history significant for cervico-thoraco-lumbar spondylitis and in the second case of an operated occipital astrocytoma. In both cases, the PPTA was associated with a fusiform aneurysm located in the carotidian (lateral) aspect of the PPTA as well as other cerebrovascular anatomic variations. In the first case, the length of the PPTA was 26.0 mm and its endoluminal diameter, at its origin at the ICA, was 1.8 mm; the aneurysm has a length of 8.4 mm. In the second case, the length of the PPTA was 31.0 mm and its endoluminal diameter at its origin at the ICA was 3.0 mm; the aneurysm have a length of 7.6 mm. Identification of these variant vessels should not be ignored before planning and execution of neurosurgeries to prevent possible perioperative risks. PMID:26662153

  2. Interindividual anatomical variations affect the plate-to-bone fit during osteosynthesis of distal radius fractures.

    PubMed

    Yoneda, Hidemasa; Iwatsuki, Katsuyuki; Hara, Tatsuya; Kurimoto, Shigeru; Yamamoto, Michiro; Hirata, Hitoshi

    2016-06-01

    We hypothesized that interindividual variations in the teardrop, which represents the volar projection of the lunate facet of the distal radius, cause unsatisfactory fitting of the volar locking plate to the bone. This can cause flexor tendon ruptures. Herein, we conducted a cross-sectional study and measured the ratio of teardrop height and the teardrop inclination angle as parameters of teardrop configuration for 200 standardized lateral radiographs (average age of the patients, 51 years). We also quantified the influence of the teardrop morphology by analyzing the fit of three locking plates to three radii with differing teardrop inclination angles using a three-dimensional computer-aided design system. The average ratios of the teardrop height and teardrop inclination angle were 0.42° (0.30-0.56°) and 28.8° (9.9-44.9°), respectively. The teardrop inclination angle was moderately correlated with age in men but not in women. In the plate-to-bone fit analyses, the fit of all the plates was significantly different between bones, with the configuration of the radius with the lowest teardrop inclination angle being the closest approximation to that of each plate. We demonstrated the interindividual variation in the shape of the teardrop and its influence on the fit of the volar plate, highlighting the importance of careful plate selection for achieving osteosynthesis of bones with a high teardrop inclination angle. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:953-960, 2016. PMID:26648456

  3. [Measures to anatomic variations of the colonic vessels in laparoscopic operations].

    PubMed

    Pan, Kai

    2013-10-01

    In laparoscopic colorectal resection, the poor blood supply of the anastomosis after tumor excision is difficult to be determined during the operations sometimes. The change in blood supply of the bowel is mainly due to the mesenteric anatomy and the operative techniques. The direct blood supply of colon is the marginal vessels in the mesentery. The integrity and patency of the marginal vessels determine the vitality of the bowel. However, the marginal vessels are different in diameter, pulsation or even discontinue in various areas, affecting the excision of the colon and following anastomosis. The most common three dangerous areas to anastomosis include:(1)area between ileocolic artery and right colonic artery; (2)area between middle colonic artery and left colonic artery-the Griffiths point. (3)area between the terminal branch of sigmoid colonic artery and superior rectal artery-Sudeck dangerous area. In laparoscopic colorectal resection, one should pay attention to protect the blood supply of the bowel and the marginal blood vessels, and be vigilant to the three vascular variations above mentioned. The vessels should be ligated accurately to ensure sufficient blood supply to the anastomosis and consequent normal healing of the rectal and colonic anastomosis. More attention should be paid to the elderly, morbid, and diabetic patients. If the safety of the anastomosis is unsure, prophylactic ileostomy should be performed. PMID:24158864

  4. Anatomical Study on the Variations in the Branching Pattern of Internal Iliac Artery.

    PubMed

    Mamatha, H; Hemalatha, B; Vinodini, P; Souza, Antony Sylvan D; Suhani, S

    2015-12-01

    The internal iliac artery (IIA) arises from the common iliac artery at the level of the sacroiliac joint. It descends as trunk, divides into anterior and posterior divisions. From the anterior division it gives superior vesical, obturator, middle rectal, inferior vesical, inferior gluteal, and internal pudendal arteries. In females, inferior vesical artery is replaced by vaginal artery and gives an additional branch, uterine artery. The branches from the posterior division are ilio lumbar, lateral sacral, and superior gluteal arteries. An accidental hemorrhage and neurovascular injuries are common due to erroneous interpretation of variant arteries during surgical procedures. Hence the present study has been undertaken with reference to highlight its clinical and surgical significances. The study included 50 human bisected pelvises irrespective of their side and sex. Formalin-fixed specimens were selected and the branching patterns of IIA were studied. The level of origin, length, and the branching pattern of the IIA were examined and tabulated. The present study highlighted the variation seen in the origin, division branches of the IIA. The detailed knowledge of morphology is essential for successful ligation of the IIA during acute hemorrhage. This will guide the interventional radiologist in intra-arterial procedures during arterial embolization for hemorrhage, control of pelvic fractures, during selective catheterization of the intra-arterial chemotherapy, and embolization of the pelvic tumors. PMID:26730003

  5. Computed tomography and magnetic resonance diagnosis of variations in the anatomical location of the major salivary glands in 1680 dogs and 187 cats.

    PubMed

    Durand, A; Finck, M; Sullivan, M; Hammond, G

    2016-03-01

    During assessment of routine clinical magnetic resonance imaging (MRI) of the heads of dogs, variations in the location of mandibular and zygomatic salivary glands (SGs) were observed incidentally. The aims of this retrospective study were to describe anatomical variations of the major SGs found on MRI and computed tomography (CT) studies of the head in dogs and cats and to investigate possible clinical relevancy. No anatomical variation of the SGs was seen in cats, but in dogs, although variation of the parotid SG was not identified, that of the mandibular SG was found in 33/1680 animals (2%), either unilaterally (6/33 right-sided, 13/33 left-sided) or bilaterally (14/33). The Border terrier breed (19/33, 58%) was over-represented. Each atypically located mandibular SG was positioned medial to the digastric muscle and rostral to the retropharyngeal lymph node. The sublingual glands were difficult to delineate from the mandibular glands. Anatomical variation of one zygomatic gland (3/4 left-sided) was identified in four small-breed dogs (0.2%). Each atypically located zygomatic gland was tilted at the ventrorostral aspect of the masseter muscle underneath the skin surface. MRI and CT characteristics were not different between typically and atypically located SGs. None of the dogs had clinical signs related with SG disease. It was concluded that, with suspected breed predispositions, incidental unilateral or bilateral anatomical variations of mandibular and zygomatic SGs can be encountered in dogs and an awareness of these possible variations may be important in pre-surgical planning. PMID:26832809

  6. Evaluation of the dosimetric impact of interfractional anatomical variations on prostate proton therapy using daily in-room CT images

    SciTech Connect

    Wang, Yi; Efstathiou, Jason A.; Sharp, Gregory C.; Lu, Hsiao-Ming; Trofimov, Alexei V.; Frank Ciernik, I.

    2011-08-15

    Purpose: To quantify interfractional anatomical variations and their dosimetric impact during the course of fractionated proton therapy (PT) of prostate cancer and to assess the robustness of the current treatment planning techniques. Methods: Simulation and daily in-room CT scans from ten prostate carcinoma patients were analyzed. PT treatment plans (78 Gy in 39 fractions of 2 Gy) were created on the simulation CT, delivering 25 fractions to PTV1 (expanded from prostate and seminal vesicles), followed by 14 boost fractions to PTV2 (expanded from prostate). Plans were subsequently applied to daily CT, with beams aligned to the prostate center in the sagittal plane. For five patients having a sufficiently large daily imaging volume, structure contours were manually drawn, and plans were evaluated for all CT sets. For the other five patients, the plans were evaluated for six selected fractions. The daily CT was matched to the simulation CT through deformable registration. The registration accuracy was validated for each fraction, and the three patients with a large number of accurately registered fractions were used for dose accumulation. Results: In individual fractions, the coverage of the prostate, seminal vesicles, and PTV1 was generally maintained at the corresponding prescription dose. For PTV2, the volume covered by the fractional prescription dose of 2 Gy (i.e., V2) was, on average, reduced by less than 3% compared to the simulation plan. Among the 225 (39 x 5 + 6 x 5) fractions examined, 15 showed a V2 reduction larger than 5%, of which ten were caused by a large variation in rectal gas, and five were due to a prostate shift in the craniocaudal direction. The fractional dose to the anterior rectal wall was found to increase for one patient who had large rectal gas volume in 25 of the 39 fractions, and another who experienced significant prostate volume reduction during the treatment. The fractional bladder dose generally increased with decreasing fullness

  7. Effectiveness of Plastinated Anatomical Specimens Depicting Common Sports Injuries to Enhance Musculoskeletal Injury Evaluation Education

    ERIC Educational Resources Information Center

    Tamura, Kaori; Stickley, Christopher D.; Labrash, Steven J.; Lozanoff, Scott

    2014-01-01

    Context: Plastination techniques have emerged as effective methods for preserving human tissue and enabling human specimens to be utilized in a fashion similar to anatomical models with much greater accuracy. Opportunities to observe and experience human specimens in classroom settings should be beneficial to undergraduate and graduate students in…

  8. A Computational Model Quantifies the Effect of Anatomical Variability on Velopharyngeal Function

    ERIC Educational Resources Information Center

    Inouye, Joshua M.; Perry, Jamie L.; Lin, Kant Y.; Blemker, Silvia S.

    2015-01-01

    Purpose: This study predicted the effects of velopharyngeal (VP) anatomical parameters on VP function to provide a greater understanding of speech mechanics and aid in the treatment of speech disorders. Method: We created a computational model of the VP mechanism using dimensions obtained from magnetic resonance imaging measurements of 10 healthy…

  9. Evaluation of Anatomic Variations in Maxillary Sinus with the Aid of Cone Beam Computed Tomography (CBCT) in a Population in South of Iran

    PubMed Central

    Shahidi, Shoaleh; Zamiri, Barbad; Momeni Danaei, Shahla; Salehi, Setareh; Hamedani, Shahram

    2016-01-01

    Statement of the Problem Anatomic variations of the maxillary sinus can be detected in cone-beam computed tomography (CBCT) and may assist to locate the posterior superior alveolar artery (PSAA) and define the maxillary sinus morphology more accurately for a more strict surgical treatment plan. Purpose The study aimed to determine normal variations of the maxillary sinus with the aid of CBCT in a sample population in south of Iran. Materials and Method This cross-sectional prevalence study was based on evaluation of 198 projection data of CBCT scans of some Iranian patients aged 18-45 who referred to a private oral and maxillofacial radiology center in Shiraz from 2011 to 2013. CBCT scans were taken and analyzed with NewTom VGi device and software. The anatomic variations which were evaluated in the axial images included the presence of alveolar pneumatization, anterior pneumatization, exostosis, and hypoplasia. Moreover the location and height of sinus septa, and the location of PSAA were assessed. SPSS software (version 17.0) was used to analyze the data. Results In a total of 396 examined sinuses, maxillary sinus alveolar pneumatization was the most common anatomic variation detected. Anterior pneumatization was detected in 96 sinuses (24.2%). Antral septa were found in 180 sinuses (45.4%) and were mostly located in the anterior region. Meanwhile, PSAA was mostly detected intra-osseous in 242 sinuses (65.7%). Conclusion Anatomic variations of the maxillary sinus were common findings in CBCT of the maxilla. Preoperative imaging with CBCT seems to be very helpful for assessing the location of PSAA and the maxillary sinus morphology, which may be used to adjust the surgical treatment plan to yield more successful treatments. PMID:26966702

  10. Estimating anatomical trajectories with Bayesian mixed-effects modeling

    PubMed Central

    Ziegler, G.; Penny, W.D.; Ridgway, G.R.; Ourselin, S.; Friston, K.J.

    2015-01-01

    We introduce a mass-univariate framework for the analysis of whole-brain structural trajectories using longitudinal Voxel-Based Morphometry data and Bayesian inference. Our approach to developmental and aging longitudinal studies characterizes heterogeneous structural growth/decline between and within groups. In particular, we propose a probabilistic generative model that parameterizes individual and ensemble average changes in brain structure using linear mixed-effects models of age and subject-specific covariates. Model inversion uses Expectation Maximization (EM), while voxelwise (empirical) priors on the size of individual differences are estimated from the data. Bayesian inference on individual and group trajectories is realized using Posterior Probability Maps (PPM). In addition to parameter inference, the framework affords comparisons of models with varying combinations of model order for fixed and random effects using model evidence. We validate the model in simulations and real MRI data from the Alzheimer's Disease Neuroimaging Initiative (ADNI) project. We further demonstrate how subject specific characteristics contribute to individual differences in longitudinal volume changes in healthy subjects, Mild Cognitive Impairment (MCI), and Alzheimer's Disease (AD). PMID:26190405

  11. Estimating anatomical trajectories with Bayesian mixed-effects modeling.

    PubMed

    Ziegler, G; Penny, W D; Ridgway, G R; Ourselin, S; Friston, K J

    2015-11-01

    We introduce a mass-univariate framework for the analysis of whole-brain structural trajectories using longitudinal Voxel-Based Morphometry data and Bayesian inference. Our approach to developmental and aging longitudinal studies characterizes heterogeneous structural growth/decline between and within groups. In particular, we propose a probabilistic generative model that parameterizes individual and ensemble average changes in brain structure using linear mixed-effects models of age and subject-specific covariates. Model inversion uses Expectation Maximization (EM), while voxelwise (empirical) priors on the size of individual differences are estimated from the data. Bayesian inference on individual and group trajectories is realized using Posterior Probability Maps (PPM). In addition to parameter inference, the framework affords comparisons of models with varying combinations of model order for fixed and random effects using model evidence. We validate the model in simulations and real MRI data from the Alzheimer's Disease Neuroimaging Initiative (ADNI) project. We further demonstrate how subject specific characteristics contribute to individual differences in longitudinal volume changes in healthy subjects, Mild Cognitive Impairment (MCI), and Alzheimer's Disease (AD). PMID:26190405

  12. Effects of anatomical position on esophageal transit time: A biomagnetic diagnostic technique

    PubMed Central

    Cordova-Fraga, Teodoro; Sosa, Modesto; Wiechers, Carlos; la Roca-Chiapas, Jose Maria De; Moreles, Alejandro Maldonado; Bernal-Alvarado, Jesus; Huerta-Franco, Raquel

    2008-01-01

    AIM: To study the esophageal transit time (ETT) and compare its mean value among three anatomical inclinations of the body; and to analyze the correlation of ETT to body mass index (BMI). METHODS: A biomagnetic technique was implemented to perform this study: (1) The transit time of a magnetic marker (MM) through the esophagus was measured using two fluxgate sensors placed over the chest of 14 healthy subjects; (2) the ETT was assessed in three anatomical positions (at upright, fowler, and supine positions; 90º, 45º and 0º, respectively). RESULTS: ANOVA and Tuckey post-hoc tests demonstrated significant differences between ETT mean of the different positions. The ETT means were 5.2 ± 1.1 s, 6.1 ± 1.5 s, and 23.6 ± 9.2 s for 90º, 45º and 0º, respectively. Pearson correlation results were r = -0.716 and P < 0.001 by subjects’ anatomical position, and r = -0.024 and P > 0.05 according the subject’s BMI. CONCLUSION: We demonstrated that using this biomagnetic technique, it is possible to measure the ETT and the effects of the anatomical position on the ETT. PMID:18837088

  13. Variation in Anatomical Position of Vermiform Appendix among Iranian Population: An Old Issue Which Has Not Lost Its Importance

    PubMed Central

    Ghorbani, Ahmad; Forouzesh, Mehdi; Kazemifar, Amir Mohammad

    2014-01-01

    Vermiform appendix has diverse anatomical positions, lengths, and conditions of mesoappendix. Knowing the exact anatomical position of vermiform appendix is important in view of surgeons for on-time diagnosis and management of acute appendicitis. The aim of present study is determination of these characteristics of vermiform appendix among Iranian population. The present study was conducted on 200 bodies, selected from the dead bodies that had been referred to local bureau of legal medicine, Zenjan province, Iran, for medicolegal autopsy since 21 Mar 2010 to 21 Mar 2011. According to the results, the anatomical positions of the appendix were pelvic, subcecal, retroileal, retrocecal, ectopic, and preileal in 55.8%, 19%, 12.5%, 7%, 4.2%, and 1.5% of the bodies, respectively. The mean length of vermiform appendix was 91.2 mm and 80.3 mm in men and women, respectively. Mesoappendix was complete in 79.5% of the bodies. No association was found between sex and anatomical position of vermiform appendix. Anterior anatomical position was the most common position for vermiform appendix. It is inconsistent with most related reports from western countries. It might be possible that some factors, such as race, geographical changes, and dietary habits, play roles in determining the position of vermiform appendix. PMID:25295193

  14. Effects of prescribed burning on ecophysiological, anatomical and stem hydraulic properties in Pinus pinea L.

    PubMed

    Battipaglia, Giovanna; Savi, Tadeja; Ascoli, Davide; Castagneri, Daniele; Esposito, Assunta; Mayr, Stefan; Nardini, Andrea

    2016-08-01

    Prescribed burning (PB) is a widespread management technique for wildfire hazard abatement. Understanding PB effects on tree ecophysiology is key to defining burn prescriptions aimed at reducing fire hazard in Mediterranean pine plantations, such as Pinus pinea L. stands. We assessed physiological responses of adult P. pinea trees to PB using a combination of dendroecological, anatomical, hydraulic and isotopic analyses. Tree-ring widths, xylem cell wall thickness, lumen area, hydraulic diameter and tree-ring δ(13)C and δ(18)O were measured in trees on burned and control sites. Vulnerability curves were elaborated to assess tree hydraulic efficiency or safety. Despite the relatively intense thermal treatment (the residence time of temperatures above 50 °C at the stem surface ranged between 242 and 2239 s), burned trees did not suffer mechanical damage to stems, nor significant reduction in radial growth. Moreover, the PB did not affect xylem structure and tree hydraulics. No variations in (13)C-derived water use efficiency were recorded. This confirmed the high resistance of P. pinea to surface fire at the stem base. However, burned trees showed consistently lower δ(18)O values in the PB year, as a likely consequence of reduced competition for water and nutrients due to the understory burning, which increased both photosynthetic activity and stomatal conductance. Our multi-approach analysis offers new perspectives on post-fire survival strategies of P. pinea in an environment where fires are predicted to increase in frequency and severity during the 21st century. PMID:27178842

  15. Effects of Instructional Strategies Using Cross Sections on the Recognition of Anatomical Structures in Correlated CT and MR Images

    ERIC Educational Resources Information Center

    Khalil, Mohammed K.; Paas, Fred; Johnson, Tristan E.; Su, Yung K.; Payer, Andrew F.

    2008-01-01

    This research is an effort to best utilize the interactive anatomical images for instructional purposes based on cognitive load theory. Three studies explored the differential effects of three computer-based instructional strategies that use anatomical cross-sections to enhance the interpretation of radiological images. These strategies include:…

  16. A Computational Model Quantifies the Effect of Anatomical Variability on Velopharyngeal Function

    PubMed Central

    Inouye, Joshua M.; Perry, Jamie L.; Lin, Kant Y.

    2015-01-01

    Purpose This study predicted the effects of velopharyngeal (VP) anatomical parameters on VP function to provide a greater understanding of speech mechanics and aid in the treatment of speech disorders. Method We created a computational model of the VP mechanism using dimensions obtained from magnetic resonance imaging measurements of 10 healthy adults. The model components included the levator veli palatini (LVP), the velum, and the posterior pharyngeal wall, and the simulations were based on material parameters from the literature. The outcome metrics were the VP closure force and LVP muscle activation required to achieve VP closure. Results Our average model compared favorably with experimental data from the literature. Simulations of 1,000 random anatomies reflected the large variability in closure forces observed experimentally. VP distance had the greatest effect on both outcome metrics when considering the observed anatomic variability. Other anatomical parameters were ranked by their predicted influences on the outcome metrics. Conclusions Our results support the implication that interventions for VP dysfunction that decrease anterior to posterior VP portal distance, increase velar length, and/or increase LVP cross-sectional area may be very effective. Future modeling studies will help to further our understanding of speech mechanics and optimize treatment of speech disorders. PMID:26049120

  17. A comparison of anatomical and dosimetric variations in the first 15 fractions, and between fractions 16 and 25, of intensity-modulated radiotherapy for nasopharyngeal carcinoma.

    PubMed

    Yang, Haihua; Tu, Yu; Wang, Wei; Hu, Wei; Ding, Weijun; Yu, Changhui; Zhou, Chao

    2013-01-01

    The purpose of this study was to compare anatomical and dosimetric variations in first 15 fractions, and between fractions 16 and 25, during intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma (NPC). Twenty-three NPC patients who received IMRT in 33 fractions were enrolled. Each patient had two repeat computed tomography (CT) scans before the 16th and 25th fraction. Hybrid IMRT plans were generated to evaluate the dosimetric changes. There was a significant decrease of the transverse diameter of nasopharyngeal and neck as well as gross tumor volume (GTV) in the primary nasopharyngeal carcinoma (GTVnx) and involved lymph nodes (GTVnd) during the first 15 fractions, and between fraction 16 and 25 (p < 0.05). Consequently, there was a significant reduction of the percentage of the volume receiving the prescribed dose (V100) of CTV1 and GTVnd, which was more prominent after the first 15 fractions treatment compared to that between fraction 16 and 25 (p < 0.05). Additionally, there was a significant increase in the mean dose (Dmean) and percentage of volume receiving ≥ 30 Gy (V30) to the bilateral parotid in the first 15 fractions (p < 0.05), but not between fraction 16 and 25. While the maximum dose to the spinal cord was significantly increased both in the first 15 fractions, and between fraction 16 and 25 (p < 0.05), the increase of the percent of spinal cord volume receiving ≥ 40 Gy (V40) was significantly higher in the first 15 fractions compared to that between fraction 16 and 25 (p < 0.05). Based on the dose constraint criterion in the RTOG0225 protocol, a total 39.1% (9/23) of phantom plan 1 (generated by applying the beam configurations of the original IMRT treatment plan to the anatomy of the second CT scan) and 17.4% (4/23) of phantom 2 (generated by applying the beam configurations of the replan 1 to the anatomy of the third CT scan) were out of limit for the dose to the normal critical structures. In conclusion, our data indicated that

  18. Near Real-Time Assessment of Anatomic and Dosimetric Variations for Head and Neck Radiation Therapy via Graphics Processing Unit–based Dose Deformation Framework

    SciTech Connect

    Qi, X. Sharon; Santhanam, Anand; Neylon, John; Min, Yugang; Armstrong, Tess; Sheng, Ke; Staton, Robert J.; Pukala, Jason; Pham, Andrew; Low, Daniel A.; Lee, Steve P.; Steinberg, Michael; Manon, Rafael; Chen, Allen M.; Kupelian, Patrick

    2015-06-01

    Purpose: The purpose of this study was to systematically monitor anatomic variations and their dosimetric consequences during intensity modulated radiation therapy (IMRT) for head and neck (H&N) cancer by using a graphics processing unit (GPU)-based deformable image registration (DIR) framework. Methods and Materials: Eleven IMRT H&N patients undergoing IMRT with daily megavoltage computed tomography (CT) and weekly kilovoltage CT (kVCT) scans were included in this analysis. Pretreatment kVCTs were automatically registered with their corresponding planning CTs through a GPU-based DIR framework. The deformation of each contoured structure in the H&N region was computed to account for nonrigid change in the patient setup. The Jacobian determinant of the planning target volumes and the surrounding critical structures were used to quantify anatomical volume changes. The actual delivered dose was calculated accounting for the organ deformation. The dose distribution uncertainties due to registration errors were estimated using a landmark-based gamma evaluation. Results: Dramatic interfractional anatomic changes were observed. During the treatment course of 6 to 7 weeks, the parotid gland volumes changed up to 34.7%, and the center-of-mass displacement of the 2 parotid glands varied in the range of 0.9 to 8.8 mm. For the primary treatment volume, the cumulative minimum and mean and equivalent uniform doses assessed by the weekly kVCTs were lower than the planned doses by up to 14.9% (P=.14), 2% (P=.39), and 7.3% (P=.05), respectively. The cumulative mean doses were significantly higher than the planned dose for the left parotid (P=.03) and right parotid glands (P=.006). The computation including DIR and dose accumulation was ultrafast (∼45 seconds) with registration accuracy at the subvoxel level. Conclusions: A systematic analysis of anatomic variations in the H&N region and their dosimetric consequences is critical in improving treatment efficacy. Nearly real

  19. The Effect of Electrode Designs Based on the Anatomical Heart Location for the Non-Contact Heart Activity Measurement.

    PubMed

    Gi, Sun Ok; Lee, Young-Jae; Koo, Hye Ran; Lee, Seung Pyo; Lee, Kang-Hwi; Kim, Kyeng-Nam; Kang, Seung-Jin; Lee, Joo Hyeon; Lee, Jeong-Whan

    2015-12-01

    This research is an extension of a previous research [1] on the different effects of sensor location that is relatively suitable for heart rate sensing. This research aimed to elucidate the causes of wide variations in heart rate measurements from the same sensor position among subjects, as observed in previous research [1], and to enhance designs of the inductive textile electrode to overcome these variations. To achieve this, this study comprised two parts: In part 1, X-ray examinations were performed to determine the cause of the wide variations noted in the findings from previous research [1], and we found that at the same sensor position, the heart activity signal differed with slight differences in the positions of the heart of each subject owing to individual differences in the anatomical heart location. In part 2, three types of dual-loop-type textile electrodes were devised to overcome variations in heart location that were confirmed in part 1 of the study. The variations with three types of sensor designs were compared with that with a single-round type of electrode design, by using computer simulation and by performing a t-test on the data obtained from the experiments. We found that the oval-oval shaped, dual-loop-type textile electrode was more suitable than the single round type for determining morphological characteristics as well as for measuring appropriate heart activity signals. Based on these results, the oval-oval, dual-loop-type was a better inductive textile electrode that more effectively overcomes individual differences in heart location during heart activity sensing based on the magnetic-induced conductivity principle. PMID:26490149

  20. Cardiac bidomain bath-loading effects during arrhythmias: interaction with anatomical heterogeneity.

    PubMed

    Bishop, Martin J; Vigmond, Edward; Plank, Gernot

    2011-12-21

    Cardiac tissue is always surrounded by conducting fluid, both in vivo (blood) and in experimental preparations (Tyrode's solution), which acts to increase conduction velocity (CV) close to the tissue-fluid interface, inducing transmural wavefront curvature. Despite its potential importance, computer modeling studies focused on arrhythmia mechanisms have previously not accounted for these bath-loading effects. Here, we investigate the increase in CV and concomitant change in transmural wavefront profiles upon both propagation and arrhythmia dynamics within models of differing anatomical complexity. In simplified slab models, in absence of transmural fiber rotation, bath-loading induced transmural wavefront curvature dominates, significantly increasing arrhythmia complexity compared to no bath. In the presence of fiber rotation, bath-loading effects are less striking and depend upon propagation direction: the bath accentuates natural concave curvature caused by transmurally rotating fibers, but attenuates convex curvature, which negates overall impact upon arrhythmia complexity. Finally, we demonstrate that the high degree of anatomical complexity within whole ventricular models modulates bath-loading induced transmural wavefront curvature. However, key is the increased surface CV that dramatically reduces both arrhythmia inducibility and resulting complexity by increasing wavelength and reducing the available excitable gap. Our findings highlight the importance of including bath-loading effects during arrhythmia mechanism investigations, which could have implications for interpreting and comparing simulation results with experimental data where such effects are inherently present. PMID:22208185

  1. The Immediate Effect of Humerus Anatomical Neck-shaft Rotation on Glenohumeral Joint Contracture

    PubMed Central

    Ohtsuki, Keisuke

    2014-01-01

    [Purpose] Elderly female patients with glenohumeral joint (GHJ) contracture, forced into prolonged immobility were examined. Range of motion exercises using humerus anatomical neck-shaft rotation were performed, and the immediate effect and adaptation were investigated. [Subjects and Methods] A total of ten individuals with a mean age of 79.4 ± 11.0 years were included in this study. The controlled intervention involved conventional range of motion exercises, and the experimental intervention involved humerus anatomical neck-shaft rotation. Each exercise was performed 30 times. Shoulder joint flexion and abduction and external rotation of the GHJ range of motion were measured with the scapula fixed. Each change in range of motion was compared using ANOVA; less than 5% was considered significant. [Results] After the experimental intervention, significant increases were seen in shoulder joint flexion, abduction, and external rotation ranges of motion. [Conclusion] Therefore, this method was effective as a means of improving the range of motion of the GHJ. PMID:24764621

  2. Anatomical considerations of the superior thyroid artery: its origins, variations, and position relative to the hyoid bone and thyroid cartilage

    PubMed Central

    2016-01-01

    The aim of this study was to provide accurate anatomical descriptions of the overall anatomy of the superior thyroid artery (STA), its relationship to other structures, and its driving patterns. Detailed dissection was performed on thirty specimens of adult's cadaveric neck specimens and each dissected specimen was carefully measured the following patterns and distances using digital and ruler. The superior thyroid, lingual, and facial arteries arise independently from the external carotid artery (ECA), but can also arise together, as the thyrolingual or linguofacial trunk. We observed that 83.3% of STAs arose independently from the major artery, while 16.7% of the cases arose from thyrolingual or linguofacial trunk. We also measured the distance of STA from its major artery. The origin of the STA from the ECA was 0.9±0.4 mm below the hyoid bone. The STA was 4.4±0.5 mm distal to the midline at the level of the laryngeal prominence and 3.1±0.6 mm distal to the midline at the level of the inferior border of thyroid cartilage. The distance between STA and the midline was similar at the level of the hyoid bone and the thyroid cartilage. Also, when the STA is near the inferior border of the thyroid cartilage, it travels at a steep angle to the midline. This latter point may be particularly important in thyroidectomies. We hope that anatomical information provided here will enhance the success of, and minimize complications in, surgeries that involve STA. PMID:27382516

  3. An Effective Manual Deboning Method To Prepare Intact Mouse Nasal Tissue With Preserved Anatomical Organization

    PubMed Central

    Dunston, David; Ogura, Tatsuya; Lin, Weihong

    2013-01-01

    The mammalian nose is a multi-functional organ with intricate internal structures. The nasal cavity is lined with various epithelia such as olfactory, respiratory, and squamous epithelia which differ markedly in anatomical locations, morphology, and functions. In adult mice, the nose is covered with various skull bones, limiting experimental access to internal structures, especially those in the posterior such as the main olfactory epithelium (MOE). Here we describe an effective method for obtaining almost the entire and intact nasal tissues with preserved anatomical organization. Using surgical tools under a dissecting microscope, we sequentially remove the skull bones surrounding the nasal tissue. This procedure can be performed on both paraformaldehyde-fixed and freshly dissected, skinned mouse heads. The entire deboning procedure takes about 20-30 min, which is significantly shorter than the experimental time required for conventional chemical-based decalcification. In addition, we present an easy method to remove air bubbles trapped between turbinates, which is critical for obtaining intact thin horizontal or coronal or sagittal sections from the nasal tissue preparation. Nasal tissue prepared using our method can be used for whole mount observation of the entire epithelia, as well as morphological, immunocytochemical, RNA in situ hybridization, and physiological studies, especially in studies where region-specific examination and comparison are of interest. PMID:23963491

  4. The prevalence of anatomical variations that can cause inadvertent dural puncture when performing caudal block in Koreans: a study using magnetic resonance imaging.

    PubMed

    Joo, J; Kim, J; Lee, J

    2010-01-01

    The purpose of this study was to investigate the prevalence of the anatomical abnormalities that can induce inadvertent dural puncture when performing caudal block. The anatomy of the lumbo-sacral area was evaluated using magnetic resonance imaging. In 2462 of the 2669 patients imaged, the dural sac terminal was located between the upper half of the 1st sacral vertebra and the lower half of the 2nd sacral vertebra. In 22 cases (0.8%), the dural sac terminal and the spinal canal were located at or below the 3rd sacral vertebra, and these were cases of simple anatomical variations. As regards pathologic conditions, there was one case of sacral meningocoele and 46 cases of sacral perineural cyst. In 21 cases (0.8%) out of the 46 perineural cyst cases, the cyst could be found at or below the 3rd sacral vertebra level. Inadvertent dural puncture may happen when performing caudal block in patients with such abnormal anatomy. PMID:19922508

  5. The dorsal sagittal venous sinus anatomical variations in brachycephalic, dolichocephalic, and mesocephalic dogs and their significance for brain surgery.

    PubMed

    Carreira, L Miguel; Ferreira, António; Burilo, Fernando Liste

    2011-11-01

    Dorsal sagittal venous sinus (DSVS) is an encephalic structure located in the midline of brain dorsal surface, starting behind the frontal venous sinus and following the brain falx in its extension. Knowing DSVS morphology and cranial-cerebral relationships it is very important for surgeon when he is planning the placement of craniotomies, in order to prevent the damage of this structure. The main purpose of this study were to establish craniometric points that can be used as key points of neurosurgical importance providing an anatomic framework to brain access regarding the localization of DSVS, and to characterize the morphology of DSVS in the three groups considered in study according their type of skull (brachycephalic-B, dolychocephalic-D and mesocephalic-M). The study was performed on 138 formalin-fixed cerebral hemispheres of 69 adult dog cadavers (23 of each group) which had been removed from the skulls after the introduction of plastic catheters through properly positioned burr holes placed on the five craniometric points considered: asterion(ast), bregma(br), glabella(g), stephanion(st) and pterion(pt). From the three groups, DSVS length and width were different, his geometry in B assumed a triangular appearance and in D, M a "butterfly" shape. From all craniometric points considered, only bregma (br) can be useful as a landmark to delimitate DSVS morphology in all three groups. Asterion in M, stephanion in B, glabella and pterion in all three groups, can not be used to compose a framework that help to understand skull surface projection of DSVS morphology, since their measurements were not uniform. PMID:21972218

  6. Dosimetric Effect of Online Image-Guided Anatomical Interventions for Postprostatectomy Cancer Patients

    SciTech Connect

    Diot, Quentin; Olsen, Christine; Kavanagh, Brian; Raben, David; Miften, Moyed

    2011-02-01

    Purpose: To assess daily variations in delivered doses in postprostatectomy patients, using kilovoltage cone-beam CT (CBCT) datasets acquired before and after interventions to correct for observed distortions in volume/shape of rectum and bladder. Methods and Materials: Seventeen consecutive patients treated with intensity-modulated radiotherapy to the prostate bed were studied. For patients with large anatomical variations, quantified by either a rectal wall displacement of >5 mm or bladder volume change of >50% on the CBCT compared with the planning CT, an intervention was performed to adjust the rectum and/or bladder filling. Cumulative doses over the pre- and post-intervention fractions were calculated by tracking the position of the planning CT voxels on different CBCTs using a deformable surface-mapping algorithm. Dose and displacements vectors were projected on two-dimensional maps, the minimal dose received by the highest 95% of the planing target volume (PTV D95) and the highest 10% of the rectum volume (D10) as well as the bladder volume receiving >2 Gy (V2) were evaluated. Results: Of 544 fractions, 96 required intervention. Median (range) number of interventions per patient was 5 (2-12). Compared with the planning values, the mean (SD) pre- vs. postintervention value for PTV D95 was -2% (2%) vs. -1% (2%) (p < 0.12), for rectum D10 was -1% (4%) vs. +1% (4%) (p < 0.24), and for bladder V2 was +6% vs. +20% (p < 0.84). Conclusions: Interventions to reduce treatment volume deformations due to bladder and rectum fillings are not necessary when patients receive daily accurate CBCT localization, and the frequency of those potential interventions is low. However, for hypofractionated treatments, the relative frequency can significantly increase, and interventions can become more dosimetrically beneficial.

  7. A 3D numerical study of the collateral capacity of the circle of Willis with anatomical variation in the posterior circulation

    PubMed Central

    2015-01-01

    Background The Circle of Willis (CoW) is the most important collateral pathway of the cerebral artery. The present study aims to investigate the collateral capacity of CoW with anatomical variation when unilateral internalcarotid artery (ICA) is occluded. Methods Basing on MRI data, we have reconstructed eight 3D models with variations in the posterior circulation of the CoW and set four different degrees of stenosis in the right ICA, namely 24%, 43%, 64% and 79%, respectively. Finally, a total of 40 models are performed with computational fluid dynamics simulations. All of the simulations share the same boundary condition with static pressure and the volume flow rate (VFR) are obtained to evaluate their collateral capacity. Results As for the middle cerebral artery (MCA) and the anterior cerebral artery (ACA), the transitional-type model possesses the best collateral capacity. But for the posterior cerebral artery (PCA), unilateral stenosis of ICA has the weakest influence on the unilateral posterior communicating artery (PCoA) absent model. We also find that the full fetal-type posterior circle of Willis is an utmost dangerous variation which must be paid more attention. Conclusion The results demonstrate that different models have different collateral capacities in coping stenosis of unilateral ICA and these differences can be reflected by different outlets. The study could be used as a reference for neurosurgeon in choosing the best treatment strategy. PMID:25603312

  8. Age-Dependent Effects of Haptoglobin Deletion in Neurobehavioral and Anatomical Outcomes Following Traumatic Brain Injury

    PubMed Central

    Glushakov, Alexander V.; Arias, Rodrigo A.; Tolosano, Emanuela; Doré, Sylvain

    2016-01-01

    Cerebral hemorrhages are common features of traumatic brain injury (TBI) and their presence is associated with chronic disabilities. Recent clinical and experimental evidence suggests that haptoglobin (Hp), an endogenous hemoglobin-binding protein most abundant in blood plasma, is involved in the intrinsic molecular defensive mechanism, though its role in TBI is poorly understood. The aim of this study was to investigate the effects of Hp deletion on the anatomical and behavioral outcomes in the controlled cortical impact model using wildtype (WT) C57BL/6 mice and genetically modified mice lacking the Hp gene (Hp−∕−) in two age cohorts [2–4 mo-old (young adult) and 7–8 mo-old (older adult)]. The data obtained suggest age-dependent significant effects on behavioral and anatomical TBI outcomes and recovery from injury. Moreover, in the adult cohort, neurological deficits in Hp−∕− mice at 24 h were significantly improved compared to WT, whereas there were no significant differences in brain pathology between these genotypes. In contrast, in the older adult cohort, Hp−∕− mice had significantly larger lesion volumes compared to WT, but neurological deficits were not significantly different. Immunohistochemistry for ionized calcium-binding adapter molecule 1 (Iba1) and glial fibrillary acidic protein (GFAP) revealed significant differences in microglial and astrocytic reactivity between Hp−∕− and WT in selected brain regions of the adult but not the older adult-aged cohort. In conclusion, the data obtained in the study provide clarification on the age-dependent aspects of the intrinsic defensive mechanisms involving Hp that might be involved in complex pathways differentially affecting acute brain trauma outcomes. PMID:27486583

  9. Anatomical disassociation of amphetamine's rewarding and aversive effects: an intracranial microinjection study.

    PubMed

    Carr, G D; White, N M

    1986-01-01

    Amphetamine has rewarding properties in some behavioral paradigms, such as self-administration and conditioned place preference (CPP), but an aversive component is also apparent when the drug is tested with the conditioned taste aversion (CTA) paradigm. The present study was an attempt to determine the neuroanatomical substrates of the drug's rewarding and aversive effects. Previous evidence suggested that amphetamine's stimulation of activity in dopaminergic synapses is critical for both effects. Amphetamine was therefore micro-injected bilaterally (10 micrograms/0.5 microliter per side) into six different dopaminergic sites, each in a different group of animals: the medial prefrontal cortex, nucleus accumbens, anteromedial caudate nucleus, lateroventral caudate nucleus, amygdala, and the region subjacent to the area postrema (AP region). The effects of these injections in both the taste and place conditioning paradigms were examined in separate experiments. Of the six sites, a significant CPP was observed only with accumbens injections and a significant CTA was observed only with AP region injections. It was concluded that the accumbens plays a primary role in mediating the rewarding effects of amphetamine and that the AP region plays a primary role in mediating the CTA. This constitutes an anatomical disassociation of amphetamine's rewarding and aversive effects. The differential associative bias of place-reward and taste-aversion learning apparent in the results is discussed. PMID:3088661

  10. Effects of instructional strategies using cross sections on the recognition of anatomical structures in correlated CT and MR images.

    PubMed

    Khalil, Mohammed K; Paas, Fred; Johnson, Tristan E; Su, Yung K; Payer, Andrew F

    2008-01-01

    This research is an effort to best utilize the interactive anatomical images for instructional purposes based on cognitive load theory. Three studies explored the differential effects of three computer-based instructional strategies that use anatomical cross-sections to enhance the interpretation of radiological images. These strategies include: (1) cross-sectional images of the head that can be superimposed on radiological images, (2) transparent highlighting of anatomical structures in radiological images, and (3) cross-sectional images of the head with radiological images presented side-by-side. Data collected included: (1) time spent on instruction and on solving test questions, (2) mental effort during instruction and test, and (3) students' performance to identify anatomical structures in radiological images. Participants were 28 freshmen medical students (15 males and 13 females) and 208 biology students (190 females and 18 males). All studies used posttest-only control group design, and the collected data were analyzed by either t test or ANOVA. In self-directed computer-based environments, the strategies that used cross sections to improve students' ability to recognize anatomic structures in radiological images showed no significant positive effects. However, when increasing the complexity of the instructional materials, cross-sectional images imposed a higher cognitive load, as indicated by higher investment of mental effort. There is not enough evidence to claim that the simultaneous combination of cross sections and radiological images has no effect on the identification of anatomical structures in radiological images for novices. Further research that control for students' learning and cognitive style is needed to reach an informative conclusion. PMID:19177385

  11. Variations in abductor pollicis longus and extensor pollicis brevis tendons in the Quervain syndrome: a surgical and anatomical study.

    PubMed

    Kulthanan, Teerawat; Chareonwat, Boonsong

    2007-01-01

    Eighty-two wrists of Thai cadavers and the wrists of 66 patients with de Quervain syndrome were studied, and the variation in the number of tendons and the fibro-osseous tunnel in the first extensor compartment were recorded. The abductor pollicis longus had more than one tendon in 73 of the cadavers (89%) and in 32 of the patients (49%) (p <0.001). The extensor pollicis brevis was a single tendon in 80 (98%) and 62 (94%) of cadavers and patients, respectively. There was division with the septum that made a fibro-osseous tunnel in the first extensor compartment in 30/82 (37%) cadavers and in 38/66 (58%) patients with de Quervain syndrome (p = 0.01). The results indicate that the number of fibro-osseous tunnels and multiple compartments in the first extensor compartment may be associated with a predisposition to de Quervain syndrome. PMID:17484184

  12. An Analysis of Visibility and Anatomic Variations of Mandibular Canal in Digital Panoramic Radiographs of Dentulous and Edentulous Patients in Northern Iran Populations

    PubMed Central

    Nemati, Somayeh; Ashouri Moghadam, Anahita; Dalili Kajan, Zahra; Mohtavipour, Seyedeh Tahereh; Amouzad, Hasan

    2016-01-01

    Statement of the Problem Insufficient information about the anatomical positions and structure of mandibular canal provokes unwanted damage to this important structure of mandible. Purpose The aim of this study was to determine the visibility and anatomical variations of mandibular canal in digital panoramic radiographs of dentulous and edentulous patients in a sample of Iranian population. Materials and Method In this retrospective-analytical research, 249 digital panoramic radiographs in dentulous group and 126 in edentulous group were studied by an expert oral and maxillofacial radiologist. In both groups, the visibility of canal borders in anterior, middle, and posterior areas were examined. In dentulous group, the distance between the canal and apex of the first and second molars were measured. Canal-to-alveolar crest distance and lower mandibular border was measured in three different points for both groups. Finally, the upper-lower positions of canals were determined. Results In both groups, most visibility occurred in 1/3 of posterior and the least visibility was detected in 1/3 of anterior, with the intermediate being the most visible part (Type 2). There was no significant difference between the left and right sides in all cases. In dentulous group, no correlation was found between the visibility, age, and gender (p> 0.05); however, canal position was related to gender (p= 0.03 and p= 0.04 in right and left sides, respectively). High position was more frequent in females and intermediate position was more common in males. In edentulous group, no correlation was found between age, gender, and canal position (p> 0.05). Conclusion The most visibility of mandibular canal was in its third posterior and the least was in its third anterior part. Although the middle position of canal was more frequently visible than the high position in this study, it does not refute the possibility of damaging the mandibular canal in critical surgeries. PMID:27284556

  13. [Compensation of the effects of shifts of anatomic positions of the heart on electrical tracings].

    PubMed

    Koechlin, R; Leblanc, P

    1986-01-01

    The heart can take different anatomical orientations in the chest of various subjects and even in the same subject. The corresponding changes in perspective can deeply affect the electrical tracings recorded by fixed standardized leads. One same electrogenesis takes many appearances, complicating the analysis. Anatomically intrinsic tracings can be obtained with O. H. Schmitt's Resolver from a usual X, Y, Z lead system. Its moving trihaedral X'', Y'', Z'', has to be brought onto the heart's axis and septum. Being directly related to the heart, these tracings become independent of the heart's anatomical position in the chest. They show the electrical to anatomical topographic relations. However, they have not been in favour because Clinicians could not relate them to their usual rules of interpretation. This Note describes how to obtain normalized tracings that can benefit from the usual criteria of interpretation, as if shifted hearts were seen in an intermediate position. A constant opposite intermediate shift is applied to the three, X'', Y'', Z'', intrinsic components to restore an arbitrary normalized position. The new X'', Y'', Z'', components follow the moving trihaedral brought on the individual anatomical position measured by X rays and echocardiography. A heart being naturally in an intermediate position gives tracings as if no Resolver was in action. Compensated (or normalized) ECG's or isopotential maps can be similarly computed. PMID:3099986

  14. Physiological, anatomical, biochemical, and cytogenetic effects of thiamethoxam treatment on Allium cepa (amaryllidaceae) L.

    PubMed

    Çavuşoğlu, Kültiğin; Yalçin, Emine; Türkmen, Zafer; Yapar, Kürşad; Sağir, Saffet

    2012-11-01

    In the present study, toxic effects of active substance thiamethoxam of the insecticide Eforia were investigated on Allium cepa L. For this aim, we used the germination percentage, root length, weight gain, malondialdehyde (MDA) level, frequency of micronucleus (MN), chromosomal aberrations (CAs), and mitotic index (MI) as indicators of toxicity. Also, the changes in the root anatomy of A. cepa seeds treated with thiamethoxam were examined. The seeds in all the treatment groups were treated with three different doses (100, 250, and 500 mg/kg) of thiamethoxam for 72 h. The results showed that there were significant alterations in the germination percentage, root length, weight gain, MDA level, MN, CAs, and MI frequency depending on application dose in the seeds exposed to thiamethoxam compared to control group. Thiamethoxam treatments significantly reduced the germination percentage, root length, and weight gain in all the treatment groups (P < 0.05). But, it caused an increase in MN and CAs formation (P < 0.05). It was also found that thiamethoxam has a mito-depressive action on mitosis, and the MI was decreased depending on the dose of applied-thiamethoxam (P < 0.05). About 100, 250, and 500 mg/kg doses of thiamethoxam significantly enhanced the lipid peroxidation and caused an increase in MDA levels at each dose treatment (P < 0.05). Some anatomical damages such as necrotic cell death, unclear vascular tissue, unclear epidermis layer, cell deformation, and unusual form of cell nucleus were observed by using light micrographs. Each dose of thiamethoxam caused severe toxic effects on A. cepa cells, and the maximum toxic effect was observed at the dose level of 500 mg/kg. PMID:21374786

  15. Egocentric mental transformation of self: effects of spatial relationship in mirror-image and anatomic imitations.

    PubMed

    Sudo, Tamami; Herai, Tomomitsu; Mogi, Ken

    2012-08-01

    Assessing the mental state of others by considering their perspective plays an important part in social communication. Imitation based on visual information represents a typical case of the translation of sensory input into action. Although humans are often successful in imitating complex actions, the mechanisms that underlie successful imitation are poorly understood. In earlier findings, it has been suggested that understanding others' minds through imitation is realized in the course of the comparison between the representations of the self and others, involving a transformation of the egocentric perspective to the allocentric one. There are two possible strategies of transformation between the representation of the self and others. One possible scenario is that the imitator perceives and imitates others as if looking in a mirror (mirror-image imitation, where, for example, the demonstrator's right hand corresponds to the imitator's left hand). Alternatively, the imitator might estimate the demonstrator's action using the anatomically congruent limb (anatomic imitation, where, for example, the demonstrator's right hand corresponds to the imitator's right hand). Here, we conducted a series of experiments in which the subjects imitated simple hand actions such as pushing a button presented from several different spatial orientations rotated at various angles. We observed that the imitators changed their strategy of imitation (mirror-image or anatomic imitation) depending on the nature of spatial configurations. Behavioral data from this study support the hypothesis that mirror-image and anatomic imitations provide complementary systems for understanding the actions and intentions of others. PMID:22729456

  16. Interpreting the effects of altered brain anatomical connectivity on fMRI functional connectivity: a role for computational neural modeling

    PubMed Central

    Horwitz, Barry; Hwang, Chuhern; Alstott, Jeff

    2013-01-01

    Recently, there have been a large number of studies using resting state fMRI to characterize abnormal brain connectivity in patients with a variety of neurological, psychiatric, and developmental disorders. However, interpreting what the differences in resting state fMRI functional connectivity (rsfMRI-FC) actually reflect in terms of the underlying neural pathology has proved to be elusive because of the complexity of brain anatomical connectivity. The same is the case for task-based fMRI studies. In the last few years, several groups have used large-scale neural modeling to help provide some insight into the relationship between brain anatomical connectivity and the corresponding patterns of fMRI-FC. In this paper we review several efforts at using large-scale neural modeling to investigate the relationship between structural connectivity and functional/effective connectivity to determine how alterations in structural connectivity are manifested in altered patterns of functional/effective connectivity. Because the alterations made in the anatomical connectivity between specific brain regions in the model are known in detail, one can use the results of these simulations to determine the corresponding alterations in rsfMRI-FC. Many of these simulation studies found that structural connectivity changes do not necessarily result in matching changes in functional/effective connectivity in the areas of structural modification. Often, it was observed that increases in functional/effective connectivity in the altered brain did not necessarily correspond to increases in the strength of the anatomical connection weights. Note that increases in rsfMRI-FC in patients have been interpreted in some cases as resulting from neural plasticity. These results suggest that this interpretation can be mistaken. The relevance of these simulation findings to the use of functional/effective fMRI connectivity as biomarkers for brain disorders is also discussed. PMID:24273500

  17. Anatomical basis of LMA variations drive to different photosynthetic and water storage strategies in two Sesleria species from mountain dry grasslands

    NASA Astrophysics Data System (ADS)

    Puglielli, Giacomo; Fiore Crescente, Maria; Frattaroli, Anna Rita; Gratani, Loretta

    2016-04-01

    Plant and leaf traits directly affect ecosystem processes ensuring carbon, nutrient and water exchanges between soil and atmosphere through the photosynthetic activity. Nevertheless, a great within sites variation in plant and leaf traits can be found resulting in different adaptive strategies in coexisting species. Leaf mass per unit of leaf area (LMA) is an important trait to understand plant functional ecology being the outcome of leaf anatomy and related to photosynthesis. We hypothesized that LMA was the main predictor of the adaptive strategies of Sesleria nitida (S1) and Sesleria juncifolia (S2), growing on the screes and on the crests of the summit area, respectively, on Mount Terminillo (Central Apennines, Loc. Sella di Leonessa, 1895 m a.s.l.). To test our hypothesis we broke LMA down into anatomical components, leaf tissue density (LTD) and thickness (LT) and then relating them to gas exchange parameters on twenty plants per species cultivated ex situ. LTD explained 69% of LMA variations in S1 while the relationship with LT was not significant. Moreover, LTD was negatively correlated with LT in S1 driving to a 17% higher volume of the intercellular air spaces, which increases the CO2 partial pressure at the carboxylation sites. This result was also attested by the significant relationship between LTD and both net photosynthesis per unit leaf area (Aa) and mass (Am) (R= 0.56 and -0.49, respectively), highlighting the role of LTD in determining the photosynthetic process in S1. LMA scaled with both LTD and LT explaining 82% and 70% of LMA variations in S2. Moreover, the positive relationship between LTD and LT (R2 = 0.52) highlighted a coordination between the variables in controlling the photosynthetic process. In particular, LTD and LT controlled the transactions of carbon and water through the leaf surface, being positively related to Aa (R= 0.93 and 0.79 for LTD and LT, respectively). Nevertheless, an increase in LT and LTD decreased Am (R = -0.9 and

  18. Demonstration of the Effect of Generic Anatomical Divisions versus Clinical Protocols on Computed Tomography Dose Estimates and Risk Burden

    PubMed Central

    Moorin, Rachael E.; Gibson, David A. J.; Forsyth, Rene K.; Fox, Richard

    2014-01-01

    Objective Choosing to undertake a CT scan relies on balancing risk versus benefit, however risks associated with CT scanning have generally been limited to broad anatomical locations, which do not provided adequate information to evaluate risk against benefit. Our study aimed to determine differences in radiation dose and risk estimates associated with modern CT scanning examinations when computed for clinical protocols compared with those using anatomical area. Methods Technical data were extracted from a tertiary hospital Picture Archiving Communication System for random samples of 20–40 CT examinations per adult clinical CT protocol. Organ and whole body radiation dose were calculated using ImPACT Monte Carlo simulation software and cancer incidence and mortality estimated using BEIR VII age and gender specific lifetime attributable risk weights. Results Thirty four unique CT protocols were identified by our study. When grouped according to anatomic area the radiation dose varied substantially, particularly for abdominal protocols. The total estimated number of incident cancers and cancer related deaths using the mean dose of anatomical area were 86 and 69 respectively. Using more specific protocol doses the estimates rose to 214 and 138 incident cancers and cancer related deaths, at least doubling the burden estimated. Conclusions Modern CT scanning produces a greater diversity of effective doses than much of the literature describes; where a lack of focus on actual scanning protocols has produced estimates that do not reflect the range and complexity of modern CT practice. To allow clinicians, patients and policy makers to make informed risk versus benefit decisions the individual and population level risks associated with modern CT practices are essential. PMID:24878841

  19. Anatomical and genetic variation of western Oxyloma (Pulmonata: Succineidae) concerning the endangered Kanab ambersnail (Oxyloma haydeni kanabense) in Arizona and Utah

    USGS Publications Warehouse

    Culver, Melanie; Herrmann, Hans-Werner; Miller, Mark; Roth, Barry; Sorenson, Jeff

    2013-01-01

    more closely related to other, non-endangered ambersnail populations across the Southwest. In contrast, the Kanab ambersnail population at Vaseys Paradise appeared to be genetically distinct from all other ambersnail populations studied. Management options for the ambersnail population at Vaseys Paradise, at the time of this study, conflict with ecosystem-wide measures proposed to benefit other natural resources in the Grand Canyon. The U.S. Fish and Wildlife Service will not revise the 1995 Kanab Ambersnail Recovery Plan until further genetic and anatomical analyses provide more fine-scale taxonomic resolution of the identity of Oxyloma populations on the Colorado Plateau and elsewhere in the American Southwest. Likewise, interagency cooperators cannot revise down-listing criteria for the Kanab ambersnail until substantial evidence is provided identifying distinct Oxyloma taxa or a larger group of conspecifics that reasonably could be managed as one species. Therefore, given the current controversy about the taxonomy of Oxyloma and the endangered Kanab ambersnail, new detailed analyses were completed of morphological and genetic variation from many Oxyloma specimens collected at 12 western North American locations. These new data have allowed us to evaluate many issues related to Kanab ambersnail taxonomy. Using this dataset, the study of shells and anatomy indicates that the holotype of Oxyloma haydeni kanabense plausibly can be regarded as a member of the same species as the populations of Oxyloma analyzed in this study. Additionally, the presence of gene flow among all populations is evidence that they are members of the same species. Almost all the observed genetic diversity can be accounted for by short-distance or long-distance dispersal events between populations in this study. Our major taxonomic conclusion is that all samples collected for this study were drawn from populations of the same species.

  20. The complexity of anatomical systems

    PubMed Central

    Grizzi, Fabio; Chiriva-Internati, Maurizio

    2005-01-01

    Background The conception of anatomical entities as a hierarchy of infinitely graduated forms and the increase in the number of observed anatomical sub-entities and structural variables has generated a growing complexity, thus highlighting new properties of organised biological matter. Results (1) Complexity is so pervasive in the anatomical world that it has come to be considered as a primary characteristic of anatomical systems. (2) Anatomical entities, when viewed at microscopic as well as macroscopic level of observation, show a different degree of complexity. (3) Complexity can reside in the structure of the anatomical system (having many diverse parts with varying interactions or an intricate architecture) or in its behaviour. Often complexity in structure and behaviour go together. (4) Complex systems admit many descriptions (ways of looking at the system) each of which is only partially true. Each way of looking at a complex system requires its own description, its own mode of analysis and its own breaking down of the system in different parts; (5) Almost all the anatomical entities display hierarchical forms: their component structures at different spatial scales or their process at different time scales are related to each other. Conclusion The need to find a new way of observing and measuring anatomical entities, and objectively quantifying their different structural changes, prompted us to investigate the non-Euclidean geometries and the theories of complexity, and to apply their concepts to human anatomy. This attempt has led us to reflect upon the complex significance of the shape of an observed anatomical entity. Its changes have been defined in relation to variations in its status: from a normal (i.e. natural) to a pathological or altered state introducing the concepts of kinematics and dynamics of anatomical forms, speed of their changes, and that of scale of their observation. PMID:16029490

  1. Effects of spatial variation of skull and cerebrospinal fluid layers on optical mapping of brain activities

    NASA Astrophysics Data System (ADS)

    Wang, Shuping; Shibahara, Nanae; Kuramashi, Daishi; Okawa, Shinpei; Kakuta, Naoto; Okada, Eiji; Maki, Atsushi; Yamada, Yukio

    2010-07-01

    In order to investigate the effects of anatomical variation in human heads on the optical mapping of brain activity, we perform simulations of optical mapping by solving the photon diffusion equation for layered-models simulating human heads using the finite element method (FEM). Particularly, the effects of the spatial variations in the thicknesses of the skull and cerebrospinal fluid (CSF) layers on mapping images are investigated. Mapping images of single active regions in the gray matter layer are affected by the spatial variations in the skull and CSF layer thicknesses, although the effects are smaller than those of the positions of the active region relative to the data points. The increase in the skull thickness decreases the sensitivity of the images to active regions, while the increase in the CSF layer thickness increases the sensitivity in general. The images of multiple active regions are also influenced by their positions relative to the data points and by their depths from the skin surface.

  2. Effect of Salinity on Biomass Yield and Physiological and Stem-Root Anatomical Characteristics of Purslane (Portulaca oleracea L.) Accessions

    PubMed Central

    Juraimi, Abdul Shukor; Rafii, M. Y.; Abdul Hamid, Azizah

    2015-01-01

    13 selected purslane accessions were subjected to five salinity levels 0, 8, 16, 24, and 32 dS m−1. Salinity effect was evaluated on the basis of biomass yield reduction, physiological attributes, and stem-root anatomical changes. Aggravated salinity stress caused significant (P < 0.05) reduction in all measured parameters and the highest salinity showed more detrimental effect compared to control as well as lower salinity levels. The fresh and dry matter production was found to increase in Ac1, Ac9, and Ac13 from lower to higher salinity levels but others were badly affected. Considering salinity effect on purslane physiology, increase in chlorophyll content was seen in Ac2, Ac4, Ac6, and Ac8 at 16 dS m−1 salinity, whereas Ac4, Ac9, and Ac12 showed increased photosynthesis at the same salinity levels compared to control. Anatomically, stem cortical tissues of Ac5, Ac9, and Ac12 were unaffected at control and 8 dS m−1 salinity but root cortical tissues did not show any significant damage except a bit enlargement in Ac12 and Ac13. A dendrogram was constructed by UPGMA based on biomass yield and physiological traits where all 13 accessions were grouped into 5 clusters proving greater diversity among them. The 3-dimensional principal component analysis (PCA) has also confirmed the output of grouping from cluster analysis. Overall, salinity stressed among all 13 purslane accessions considering biomass production, physiological growth, and anatomical development Ac9 was the best salt-tolerant purslane accession and Ac13 was the most affected accession. PMID:25802833

  3. Validation of semi-quantitative methods for DAT SPECT: influence of anatomical variability and partial volume effect

    NASA Astrophysics Data System (ADS)

    Gallego, J.; Niñerola-Baizán, A.; Cot, A.; Aguiar, P.; Crespo, C.; Falcón, C.; Lomeña, F.; Sempau, J.; Pavía, J.; Ros, D.

    2015-08-01

    The aim of this work was to evaluate the influence of anatomical variability between subjects and of the partial volume effect (PVE) on the standardized Specific Uptake Ratio (SUR) in [123I]FP-bib SPECT studies. To this end, magnetic resonance (MR) images of 23 subjects with differences in the striatal volume of up to 44% were segmented and used to generate a database of 138 Monte Carlo simulated SPECT studies. Data included normal uptakes and pathological cases. Studies were reconstructed by filtered back projection (FBP) and the ordered-subset expectation-maximization algorithm. Quantification was carried out by applying a reference method based on regions of interest (ROIs) derived from the MR images and ROIs derived from the Automated Anatomical Labelling map. Our results showed that, regardless of anatomical variability, the relationship between calculated and true SUR values for caudate and putamen could be described by a multiple linear model which took into account the spill-over phenomenon caused by PVE ({{R}2}≥slant 0.963 for caudate and ≥0.980 for putamen) and also by a simple linear model (R2 ≥ 0.952 for caudate and ≥0.973 for putamen). Calculated values were standardized by inverting both linear systems. Differences between standardized and true values showed that, although the multiple linear model was the best approach in terms of variability ({χ2}  ≥ 11.79 for caudate and  ≤7.36 for putamen), standardization based on a simple linear model was also suitable ({χ2}  ≥ 12.44 for caudate and  ≤12.57 for putamen).

  4. SU-C-210-05: Evaluation of Robustness: Dosimetric Effects of Anatomical Changes During Fractionated Radiation Treatment of Pancreatic Cancer Patients

    SciTech Connect

    Horst, A van der; Houweling, A C; Bijveld, M M C; Visser, J; Bel, A

    2015-06-15

    Purpose: Pancreatic tumors show large interfractional position variations. In addition, changes in gastrointestinal air volume and body contour take place during treatment. We aim to investigate the robustness of the clinical treatment plans by quantifying the dosimetric effects of these anatomical changes. Methods: Calculations were performed for up to now 3 pancreatic cancer patients who had intratumoral fiducials for daily CBCT-based positioning during their 3-week treatment. For each patient, deformable image registration of the planning CT was used to assign Hounsfield Units to each of the 13—15 CBCTs; air volumes and body contour were copied from CBCT. The clinical treatment plan was used (CTV-PTV margin = 10 mm; 36Gy; 10MV; 1 arc VMAT). Fraction dose distributions were calculated and accumulated. The V95% of the clinical target volume (CTV) and planning target volume (PTV) were analyzed, as well as the dose to stomach, duodenum and liver. Dose accumulation was done for patient positioning based on the fiducials (as clinically used) as well as for positioning based on bony anatomy. Results: For all three patients, the V95% of the CTV remained 100%, for both fiducial- and bony anatomy-based positioning. For fiducial-based positioning, dose to duodenum en stomach showed no discernable differences with planned dose. For bony anatomy-based positioning, the PTV V95% of the patient with the largest systematic difference in tumor position (patient 1) decreased to 85%; the liver Dmax increased from 33.5Gy (planned) to 35.5Gy. Conclusion: When using intratumoral fiducials, CTV dose coverage was only mildly affected by the daily anatomical changes. When using bony anatomy for patient positioning, we found a decline in PTV dose coverage due to the interfractional tumor position variations. Photon irradiation treatment plans for pancreatic tumors are robust to variations in body contour and gastrointestinal gas, but the use of fiducial-based daily position verification

  5. The effects of anatomical information and observer expertise on abnormality detection task

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Cavaro-Ménard, C.; Le Callet, P.; Cooper, L. H. K.; Hunault, G.; Tanguy, J.-Y.

    2011-03-01

    This paper presents a novel study investigating the influences of Magnetic Resonance (MR) image anatomical information and observer expertise on an abnormality detection task. MRI is exquisitely sensitive for detecting brain abnormalities, particularly in the evaluation of white matter diseases, e.g. multiple sclerosis (MS). For this reason, MS lesions are simulated as the target stimuli for detection in the present study. Two different image backgrounds are used in the following experiments: a) homogeneous region of white matter tissue, and b) one slice of a healthy brain MR image. One expert radiologist (more than 10 years' experience), three radiologists (less than 5 years' experience) and eight naïve observers (without any prior medical knowledge) have performed these experiments, during which they have been asked different questions dependent upon level of experience; the three radiologists and eight naïve observers were asked if they were aware of any hyper-signal, likely to represent an MS lesion, while the most experienced consultant was asked if a clinically significant sign was present. With the percentages of response "yes" displayed on the y-axis and the lesion intensity contrasts on the x-axis, psychometric function is generated from the observer' responses. Results of psychometric functions and calculated thresholds indicate that radiologists have better hyper-signal detection ability than naïve observers, which is intuitively shown by the lower simple visibility thresholds of radiologists. However, when radiologists perform a task with clinical implications, e.g. to detect a clinically significant sign, their detection thresholds are elevated. Moreover, the study indicates that for the radiologists, the simple visibility thresholds remain the same with and without the anatomical information, which reduces the threshold for the clinically significant sign detection task. Findings provide further insight into human visual system processing for this

  6. Local Recurrence in Rectal Cancer: Anatomic Localization and Effect on Radiation Target

    SciTech Connect

    Syk, Erik Torkzad, Michael R.; Blomqvist, Lennart; Nilsson, Per J.; Glimelius, Bengt

    2008-11-01

    Purpose: To determine the sites of local recurrence after total mesorectal excision for rectal cancer in an effort to optimize the radiation target. Methods and Materials: A total of 155 patients with recurrence after abdominal resection for rectal cancer were identified from a population-based consecutive cohort of 2,315 patients who had undergone surgery by surgeons trained in the total mesorectal excision procedure. A total of 99 cross-sectional imaging studies were retrieved and re-examined by one radiologist. The clinical records were examined for the remaining patients. Results: Evidence of residual mesorectal fat was identified in 50 of the 99 patients. In 83 patients, local recurrence was identified on the imaging studies. All recurrences were within the irradiated volume if the patients had undergone preoperative radiotherapy or within the same volume if they had not. The site of recurrence was in the lower 75% of the pelvis, anatomically below the S1-S2 interspace for all patients. Only 5 of the 44 recurrences in patients with primary tumors >5 cm from the anal verge were in the lowest 20% of the pelvis. Six recurrences involved the lateral lymph nodes. Conclusion: These data suggest that a lowering of the upper limit of the clinical target volume could be introduced. The anal sphincter complex with surrounding tissue could also be excluded in patients with primary tumors >5 cm from the anal verge.

  7. The significance of cone beam computed tomography for the visualization of anatomical variations and lesions in the maxillary sinus for patients hoping to have dental implant-supported maxillary restorations in a private dental office in Japan

    PubMed Central

    2014-01-01

    Objectives The purpose of the present study was to elucidate the significance of cone bean computed tomography (CBCT) for patients hoping to undergo implant-supported restorations of the maxilla. Therefore, two studies were planned. One was to compare the prevalence of anatomic variations and lesions in the maxillary sinus on CBCT of patients hoping to undergo implant-supported restorations of the maxilla with that in patients with other chief complaints in a private dental office in Japan. The other study was to elucidate the limitations of panoramic radiographs in the detection of anatomic variations and lesions in the maxillary sinus. Study design Sixty-one pairs of panoramic radiographs and CBCT were retrospectively analyzed in two groups of patients, those who hoped to undergo implant-supported restorations in the maxilla (Implant group) and those who did not (Non-implant group). The presence of anatomic variations and lesions in the maxillary sinus were analyzed. Results The detection rate of mucosal thickening was significantly higher in the Implant group than in the Non-implant group. The detection rates for the features analyzed were significantly lower on panoramic radiographs. In particular, the detection rates of internal and anterior locations of some features were noticeably lower on panoramic radiographs. A significant relationship was found between the change in the detection rate on panoramic radiographs and the widths of mucosal thickening or the lengths of the major axis of SOLs in the maxillary sinus. If the width of mucosal thickening or the length of the major axis of SOLs was <3 mm or <4 mm, respectively, the detection rate on panoramic radiographs was significantly decreased. Conclusion CBCT is important for patients hoping to undergo implant-supported restorations of the maxilla because of the mucosal thickening in the maxillary sinus in such patients and their lower detection rates on panoramic radiographs. PMID:24884983

  8. Prediction of tissue-specific effects of gene knockout on apoptosis in different anatomical structures of human brain

    PubMed Central

    2015-01-01

    Background An important issue in the target identification for the drug design is the tissue-specific effect of inhibition of target genes. The task of assessing the tissue-specific effect in suppressing gene activity is especially relevant in the studies of the brain, because a significant variability in gene expression levels among different areas of the brain was well documented. Results A method is proposed for constructing statistical models to predict the potential effect of the knockout of target genes on the expression of genes involved in the regulation of apoptosis in various brain regions. The model connects the expression of the objective group of genes with expression of the target gene by means of machine learning models trained on available expression data. Information about the interactions between target and objective genes is determined by reconstruction of target-centric gene network. STRING and ANDSystem databases are used for the reconstruction of gene networks. The developed models have been used to analyse gene knockout effects of more than 7,500 target genes on the expression of 1,900 objective genes associated with the Gene Ontology category "apoptotic process". The tissue-specific effect was calculated for 12 main anatomical structures of the human brain. Initial values of gene expression in these anatomical structures were taken from the Allen Brain Atlas database. The results of the predictions of the effect of suppressing the activity of target genes on apoptosis, calculated on average for all brain structures, were in good agreement with experimental data on siRNA-inhibition. Conclusions This theoretical paper presents an approach that can be used to assess tissue-specific gene knockout effect on gene expression of the studied biological process in various structures of the brain. Genes that, according to the predictions of the model, have the highest values of tissue-specific effects on the apoptosis network can be considered as

  9. Effects of temperature variation on MOSFET dosimetry.

    PubMed

    Cheung, Tsang; Butson, Martin J; Yu, Peter K N

    2004-07-01

    This note investigates temperature effects on dosimetry using a metal oxide semiconductor field effect transistor (MOSFET) for radiotherapy x-ray treatment. This was performed by analysing the dose response and threshold voltage outputs for MOSFET dosimeters as a function of ambient temperature. Results have shown that the clinical semiconductor dosimetry system (CSDS) MOSFET provides stable dose measurements with temperatures varying from 15 degrees C up to 40 degrees C. Thus standard irradiations performed at room temperature can be directly compared to in vivo dose assessments performed at near body temperature without a temperature correction function. The MOSFET dosimeter threshold voltage varies with temperature and this level is dependent on the dose history of the MOSFET dosimeter. However, the variation can be accounted for in the measurement method. For accurate dosimetry, the detector should be placed for approximately 60 s on a patient to allow thermal equilibrium before measurements are taken with the final reading performed whilst still attached to the patient or conversely left for approximately 120 s after removal from the patient if initial readout was measured at room temperature to allow temperature equilibrium to be established. PMID:15285264

  10. THE EFFECT OF ADAPTIVE STATISTICAL ITERATIVE RECONSTRUCTION ON THE ASSESSMENT OF DIAGNOSTIC IMAGE QUALITY AND VISUALISATION OF ANATOMICAL STRUCTURES IN PAEDIATRIC CEREBRAL CT EXAMINATIONS.

    PubMed

    Larsson, Joel; Båth, Magnus; Ledenius, Kerstin; Thilander-Klang, Anne

    2016-06-01

    The purpose of this study was to investigate the effect of adaptive statistical iterative reconstruction (ASiR) on the visualisation of anatomical structures and diagnostic image quality in paediatric cerebral computed tomography (CT) examinations. Forty paediatric patients undergoing routine cerebral CT were included in the study. The raw data from CT scans were reconstructed into stacks of 5 mm thick axial images at various levels of ASiR. Three paediatric radiologists rated six questions related to the visualisation of anatomical structures and one question on diagnostic image quality, in a blinded randomised visual grading study. The evaluated anatomical structures demonstrated enhanced visibility with increasing level of ASiR, apart from the cerebrospinal fluid space around the brain. In this study, 60 % ASiR was found to be the optimal level of ASiR for paediatric cerebral CT examinations. This shows that the commonly used 30 % ASiR may not always be the optimal level. PMID:26873712

  11. Passive vs. active virtual reality learning: the effects on short- and long-term memory of anatomical structures.

    PubMed

    Phelps, Andrew; Fritchle, Alicia; Hoffman, Helene

    2004-01-01

    This pilot study compares the differences in learning outcomes when students are presented with either an active (student-centered) or passive (teacher-centered) virtual reality-based anatomy lesson. The "active" lesson used UCSD's Anatomic VisualizeR and enabled students to interact with 3D models and control presentation of learning materials. The "passive" lesson used a digital recording of an anatomical expert's tour of the same VR lesson played back as a QuickTime movie. Subsequent examination of the recall and retention of the studied anatomic objects were comparable in both groups. Issues underlying these results are discussed. PMID:15544293

  12. Response to neonatal anesthesia: effect of sex on anatomical and behavioral outcome.

    PubMed

    Rothstein, S; Simkins, T; Nuñez, J L

    2008-04-01

    Numerous studies have documented the consequences of exposure to anesthesia in models of term and post-term infants, evaluating the incidence of cell loss, physiological alterations and cognitive dysfunction. However, surprisingly few studies have investigated the effect of anesthetic exposure on outcomes in newborn rodents, the developmental equivalent of premature human infants. This is critical given that one out of every eight babies born in the United States is premature, with an increased prevalence of surgical procedures required in these individuals. Also, no studies have investigated if the genetic sex of the individual influences the response to neonatal anesthesia. Using the newborn rat as the developmental equivalent of the premature human, we documented the effect of a single bout of exposure to either the inhalant isoflurane or the injectable barbiturate phenobarbital on hippocampal anatomy, hippocampal dependent behavioral performance and normal developmental endpoints in male and female rats. While both forms of anesthesia led to significant decrements in cognitive abilities, along with a significant reduction in volume and neuron number in the hippocampus in adulthood, the decrements were significantly greater in males than in females. Interestingly, the deleterious effects of anesthesia were manifest on developmental measures including surface righting and forelimb grasp, but were not evident on basic physiological parameters including body weight or suckling. These findings point to the hazardous effects of exposure to anesthesia on the developing CNS and the particular sensitivity of males to deficits. PMID:18329814

  13. The Effect of Anatomic Factors on Tongue Position Variability during Consonants

    ERIC Educational Resources Information Center

    Rudy, Krista; Yunusova, Yana

    2013-01-01

    Purpose: This study sought to investigate the effect of palate morphology and anthropometric measures of the head on positional variability of the tongue during consonants. Method: An electromagnetic tracking system was used to record tongue movements of 21 adults. Each talker produced a series of symmetrical VCV syllables containing one of the…

  14. Anatomical, morphological, and phytochemical effects of inoculation with plant growth- promoting rhizobacteria on peppermint (Mentha piperita).

    PubMed

    del Rosario Cappellari, Lorena; Santoro, Maricel Valeria; Reinoso, Herminda; Travaglia, Claudia; Giordano, Walter; Banchio, Erika

    2015-02-01

    Plant growth-promoting rhizobacteria (PGPR) generally exert their effects through enhancement of plant nutrient status and/or phytohormone production. The effects of PGPR on aromatic plant species are poorly known. We measured plant growth parameters, chlorophyll content, trichome density, stomatal density, and levels of secondary metabolites in peppermint (Mentha piperita) seedlings inoculated with PGPR strains Bacillus subtilis GB03, Pseudomonas fluorescens WCS417r, P. putida SJ04, or a combination of WCS417r + SJ04. The treated plants, in comparison with controls, showed increases in shoot biomass, root biomass, leaf area, node number, trichome density, and stomatal density, and marked qualitative and quantitative changes in monoterpene content. Improved knowledge of the factors that control or affect biosynthesis of secondary metabolites and monoterpene accumulation will lead to strategies for improved cultivation and productivity of aromatic plants and other agricultural crops without the use of chemical fertilizers or pesticides. PMID:25655927

  15. Effects of Aging and Anatomic Location on Gene Expression in Human Retina

    PubMed Central

    Cai, Hui; Fields, Mark A.; Hoshino, Risa; Priore, Lucian V. Del

    2012-01-01

    Objective: To determine the effects of age and topographic location on gene expression in human neural retina. Methods: Macular and peripheral neural retina RNA was isolated from human donor eyes for DNA microarray and quantitative RT-PCR analyses. Results: Total RNA integrity from human donors was preserved. Hierarchical clustering analysis demonstrates that the gene expression profiles of young, old, macula, and peripheral retina cluster into four distinct groups. Genes which are highly expressed in macular, peripheral, young, or old retina were identified, including inhibitors of Wnt Signaling Pathway (DKK1, FZD10, and SFRP2) which are preferably expressed in the periphery. Conclusion: The transcriptome of the human retina is affected by age and topographic location. Wnt pathway inhibitors in the periphery may maintain peripheral retinal cells in an undifferentiated state. Understanding the effects of age and topographic location on gene expression may lead to the development of new therapeutic interventions for age-related eye diseases. PMID:22666212

  16. Effect of anatomical fine structure on the flow of cerebrospinal fluid in the spinal subarachnoid space.

    SciTech Connect

    Stockman, Harlan Wheelock

    2005-01-01

    The lattice Boltzmann method is used to model oscillatory flow in the spinal subarachnoid space. The effect of obstacles such as trabeculae, nerve bundles, and ligaments on fluid velocity profiles appears to be small, when the flow is averaged over the length of a vertebra. Averaged fluid flow in complex models is little different from flow in corresponding elliptical annular cavities. However, the obstacles stir the flow locally and may be more significant in studies of tracer dispersion.

  17. Effect of Anatomically Realistic Full-Head Model on Activation of Cortical Neurons in Subdural Cortical Stimulation—A Computational Study

    PubMed Central

    Seo, Hyeon; Kim, Donghyeon; Jun, Sung Chan

    2016-01-01

    Electrical brain stimulation (EBS) is an emerging therapy for the treatment of neurological disorders, and computational modeling studies of EBS have been used to determine the optimal parameters for highly cost-effective electrotherapy. Recent notable growth in computing capability has enabled researchers to consider an anatomically realistic head model that represents the full head and complex geometry of the brain rather than the previous simplified partial head model (extruded slab) that represents only the precentral gyrus. In this work, subdural cortical stimulation (SuCS) was found to offer a better understanding of the differential activation of cortical neurons in the anatomically realistic full-head model than in the simplified partial-head models. We observed that layer 3 pyramidal neurons had comparable stimulation thresholds in both head models, while layer 5 pyramidal neurons showed a notable discrepancy between the models; in particular, layer 5 pyramidal neurons demonstrated asymmetry in the thresholds and action potential initiation sites in the anatomically realistic full-head model. Overall, the anatomically realistic full-head model may offer a better understanding of layer 5 pyramidal neuronal responses. Accordingly, the effects of using the realistic full-head model in SuCS are compelling in computational modeling studies, even though this modeling requires substantially more effort. PMID:27273817

  18. Effect of Anatomically Realistic Full-Head Model on Activation of Cortical Neurons in Subdural Cortical Stimulation-A Computational Study.

    PubMed

    Seo, Hyeon; Kim, Donghyeon; Jun, Sung Chan

    2016-01-01

    Electrical brain stimulation (EBS) is an emerging therapy for the treatment of neurological disorders, and computational modeling studies of EBS have been used to determine the optimal parameters for highly cost-effective electrotherapy. Recent notable growth in computing capability has enabled researchers to consider an anatomically realistic head model that represents the full head and complex geometry of the brain rather than the previous simplified partial head model (extruded slab) that represents only the precentral gyrus. In this work, subdural cortical stimulation (SuCS) was found to offer a better understanding of the differential activation of cortical neurons in the anatomically realistic full-head model than in the simplified partial-head models. We observed that layer 3 pyramidal neurons had comparable stimulation thresholds in both head models, while layer 5 pyramidal neurons showed a notable discrepancy between the models; in particular, layer 5 pyramidal neurons demonstrated asymmetry in the thresholds and action potential initiation sites in the anatomically realistic full-head model. Overall, the anatomically realistic full-head model may offer a better understanding of layer 5 pyramidal neuronal responses. Accordingly, the effects of using the realistic full-head model in SuCS are compelling in computational modeling studies, even though this modeling requires substantially more effort. PMID:27273817

  19. Effect of Anatomically Realistic Full-Head Model on Activation of Cortical Neurons in Subdural Cortical Stimulation—A Computational Study

    NASA Astrophysics Data System (ADS)

    Seo, Hyeon; Kim, Donghyeon; Jun, Sung Chan

    2016-06-01

    Electrical brain stimulation (EBS) is an emerging therapy for the treatment of neurological disorders, and computational modeling studies of EBS have been used to determine the optimal parameters for highly cost-effective electrotherapy. Recent notable growth in computing capability has enabled researchers to consider an anatomically realistic head model that represents the full head and complex geometry of the brain rather than the previous simplified partial head model (extruded slab) that represents only the precentral gyrus. In this work, subdural cortical stimulation (SuCS) was found to offer a better understanding of the differential activation of cortical neurons in the anatomically realistic full-head model than in the simplified partial-head models. We observed that layer 3 pyramidal neurons had comparable stimulation thresholds in both head models, while layer 5 pyramidal neurons showed a notable discrepancy between the models; in particular, layer 5 pyramidal neurons demonstrated asymmetry in the thresholds and action potential initiation sites in the anatomically realistic full-head model. Overall, the anatomically realistic full-head model may offer a better understanding of layer 5 pyramidal neuronal responses. Accordingly, the effects of using the realistic full-head model in SuCS are compelling in computational modeling studies, even though this modeling requires substantially more effort.

  20. Oscillatory spatial profile of alcohol's effects on the resting state: anatomically-constrained MEG.

    PubMed

    Rosen, Burke Q; O'Hara, Ryan; Kovacevic, Sanja; Schulman, Andrew; Padovan, Nevena; Marinkovic, Ksenija

    2014-03-01

    It has been firmly established that opening and closing the eyes strongly modulate the electro- and magnetoencephalography (EEG and MEG) signals acquired during wakeful rest. Certain features of the resting EEG are altered in chronic alcoholics and their offspring, and have been proposed as biomarkers for alcoholism. Spontaneous brain oscillations are also affected by pharmacological manipulations, but the spectral and spatial characteristics of these changes are not clear. This study examined effects of the eyes-open (EO) and eyes-closed (EC) resting paradigm and alcohol challenge on the spatial profile of spontaneous MEG and EEG oscillations. Whole-head MEG and scalp EEG signals were acquired simultaneously from healthy social drinkers (n = 17) who participated in both alcohol (0.6 g/kg ethanol for men, 0.55 g/kg for women) and placebo conditions in a counterbalanced design. Power of the signal was calculated with Fast Fourier Transform and was decomposed into its constituent theta (4-7 Hz), alpha (8-12 Hz), and beta (15-20 Hz) frequency bands. High-resolution structural MRI images were additionally obtained from all participants and used to constrain distributed minimum norm inverse source power estimates. The spatial estimates of the main generator nodes were in agreement with studies using a combined fMRI-EEG approach. Alpha band oscillations dominated the spectral profile and their source was estimated to the medial parieto-occipital area. Power in theta and beta bands was weaker overall and their sources were estimated to a more focal medial prefrontal area. EO and EC manipulation most strongly modulated power in the alpha band, but a wide-band power increase was observed during the EC condition. Alcohol intoxication increased alpha power, particularly during the EC condition. Application of this methodology to cohorts of chronic alcoholics or individuals at risk could potentially provide insight into the neural basis of oscillatory differences that

  1. Effect of the anatomical site on telomere length and pref-1 gene expression in bovine adipose tissues

    SciTech Connect

    Yamada, Tomoya Higuchi, Mikito; Nakanishi, Naoto

    2015-08-07

    Adipose tissue growth is associated with preadipocyte proliferation and differentiation. Telomere length is a biological marker for cell proliferation. Preadipocyte factor-1 (pref-1) is specifically expressed in preadipocytes and acts as a molecular gatekeeper of adipogenesis. In the present study, we investigated the fat depot-specific differences in telomere length and pref-1 gene expression in various anatomical sites (subcutaneous, intramuscular and visceral) of fattening Wagyu cattle. Visceral adipose tissue expressed higher pref-1 mRNA than did subcutaneous and intramuscular adipose tissues. The telomere length in visceral adipose tissue tended to be longer than that of subcutaneous and intramuscular adipose tissues. The telomere length of adipose tissue was not associated with adipocyte size from three anatomical sites. No significant correlation was found between the pref-1 mRNA level and the subcutaneous adipocyte size. In contrast, the pref-1 mRNA level was negatively correlated with the intramuscular and visceral adipocyte size. These results suggest that anatomical sites of adipose tissue affect the telomere length and expression pattern of the pref-1 gene in a fat depot-specific manner. - Highlights: • Visceral adipose tissue express higher pref-1 mRNA than other anatomical sites. • Telomere length in visceral adipose tissue is longer than other anatomical sites. • Telomere length of adipose tissue is not associated with adipocyte size. • Pref-1 mRNA is negatively correlated with intramuscular and visceral adipocyte size.

  2. Observing System Variations Effect on Reanalyses

    NASA Technical Reports Server (NTRS)

    Bosilovich, Michael G.; Chen, Junye; Robertson, Franklin R.; da Silva, Arlindo

    2010-01-01

    Reanalyses integrate multitudes of satellite and conventional observations data assimilation and numerical weather prediction. The result is that many disparate observation platforms, discontinuous in space and time, lead to complete and consistent representations the state of the weather. The component also provides physical fields rarely or never observed. However, the numerical model bias is continuously being corrected by the observational analysis, and this bias changes as variations in the observations occur. NASA's Modern Era Retrospective-analysis for Research and Applications (MERRA) sensitivity to variations in the observing systems are explored. Specifically, we will evaluate the water budget and transport processes as they relate to the advent of SSM/I and AMSU-A radiance assimilation, and an additional case of radiosonde station that exhibits a dramatic shift in mean water states. The MERRA input observation data, now available online, is used to explore these variations.

  3. PREVALENCE OF ANATOMICAL VARIATION OF THE SIXTH CERVICAL VERTEBRA AND ASSOCIATION WITH VERTEBRAL CANAL STENOSIS AND ARTICULAR PROCESS OSTEOARTHRITIS IN THE HORSE.

    PubMed

    DeRouen, Anthony; Spriet, Mathieu; Aleman, Monica

    2016-05-01

    The sixth cervical vertebra (C6) has unique morphology due to a ventral extension from the transverse process known as the ventral lamina. Little information was found regarding the prevalence and clinical relevance of morphologic variations. Aims of this observational, retrospective study were to characterize C6 morphologic variations in a large sample of horses. Cervical radiographic studies of 100 horses were retrieved. Data recorded were signalment, clinical history, morphology of the C6 ventral lamina, presence of articular process osteoarthritis, and presence of static vertebral canal stenosis. Morphologic variations were found in C6 vertebrae for 24/100 horses, with symmetric absence of the ventral lamina in nine horses and asymmetric absence in 15. Anomalous C6 vertebrae were more common in Warmbloods, with 19/55 Warmbloods in the population being affected (P = 0.006). No association was found with sex. There was no significant difference in the mean of the intravertebral sagittal ratios between horses with normal or anomalous C6 vertebrae; however there was a significantly greater proportion of horses with anomalous C6 vertebrae that had an intravertebral sagittal ratio of less than 0.5 at C6 (P = 0.047). There was no association between the morphology of C6 and articular process osteoarthritis. Anomalous C6 vertebrae in our population were associated with a higher likelihood of cervical pain (P = 0.013). Authors propose that morphologic variations in the C6 ventral laminae could be linked to other developmental abnormalities such as vertebral canal stenosis, might affect regional biomechanics and should therefore be considered clinically relevant in horses. Future, controlled prospective studies are needed to test this theory. PMID:26915973

  4. TOPICAL REVIEW: Anatomical imaging for radiotherapy

    NASA Astrophysics Data System (ADS)

    Evans, Philip M.

    2008-06-01

    scans is taken on different days. Both allow planning to account for variability intrinsic to the patient. Treatment verification has been carried out using a variety of technologies including: MV portal imaging, kV portal/fluoroscopy, MVCT, conebeam kVCT, ultrasound and optical surface imaging. The various methods have their pros and cons. The four x-ray methods involve an extra radiation dose to normal tissue. The portal methods may not generally be used to visualize soft tissue, consequently they are often used in conjunction with implanted fiducial markers. The two CT-based methods allow measurement of inter-fraction variation only. Ultrasound allows soft-tissue measurement with zero dose but requires skilled interpretation, and there is evidence of systematic differences between ultrasound and other data sources, perhaps due to the effects of the probe pressure. Optical imaging also involves zero dose but requires good correlation between the target and the external measurement and thus is often used in conjunction with an x-ray method. The use of anatomical imaging in radiotherapy allows treatment uncertainties to be determined. These include errors between the mean position at treatment and that at planning (the systematic error) and the day-to-day variation in treatment set-up (the random error). Positional variations may also be categorized in terms of inter- and intra-fraction errors. Various empirical treatment margin formulae and intervention approaches exist to determine the optimum strategies for treatment in the presence of these known errors. Other methods exist to try to minimize error margins drastically including the currently available breath-hold techniques and the tracking methods which are largely in development. This paper will review anatomical imaging techniques in radiotherapy and how they are used to boost the therapeutic benefit of the treatment.

  5. Severe Feeding Problems Secondary to Anatomical Disorders: Effectiveness of Behavioural Treatment in Three School-Aged Children

    ERIC Educational Resources Information Center

    de Moor, Jan; Didden, Robert; Tolboom, Jules

    2005-01-01

    In the present study, behavioural treatment is described of three school-aged children with severe feeding problems caused by (surgically corrected) anatomical disorders of the digestive system. Two children showed food refusal and were tube-fed whereas the third child showed extreme food selectivity. During treatment, shaping, (non)verbal…

  6. Evaluation of the effects of anatomic location, histologic processing, and sample size on shrinkage of skin samples obtained from canine cadavers.

    PubMed

    Reagan, Jennifer K; Selmic, Laura E; Garrett, Laura D; Singh, Kuldeep

    2016-09-01

    OBJECTIVE To evaluate effects of anatomic location, histologic processing, and sample size on shrinkage of excised canine skin samples. SAMPLE Skin samples from 15 canine cadavers. PROCEDURES Elliptical samples of the skin, underlying subcutaneous fat, and muscle fascia were collected from the head, hind limb, and lumbar region of each cadaver. Two samples (10 mm and 30 mm) were collected at each anatomic location of each cadaver (one from the left side and the other from the right side). Measurements of length, width, depth, and surface area were collected prior to excision (P1) and after fixation in neutral-buffered 10% formalin for 24 to 48 hours (P2). Length and width were also measured after histologic processing (P3). RESULTS Length and width decreased significantly at all anatomic locations and for both sample sizes at each processing stage. Hind limb samples had the greatest decrease in length, compared with results for samples obtained from other locations, across all processing stages for both sample sizes. The 30-mm samples had a greater percentage change in length and width between P1 and P2 than did the 10-mm samples. Histologic processing (P2 to P3) had a greater effect on the percentage shrinkage of 10-mm samples. For all locations and both sample sizes, percentage change between P1 and P3 ranged from 24.0% to 37.7% for length and 18.0% to 22.8% for width. CONCLUSIONS AND CLINICAL RELEVANCE Histologic processing, anatomic location, and sample size affected the degree of shrinkage of a canine skin sample from excision to histologic assessment. PMID:27580116

  7. The superior mesenteric artery and the variations of the colic patterns. A new anatomical and radiological classification of the colic arteries.

    PubMed

    Gamo, E; Jiménez, C; Pallares, E; Simón, C; Valderrama, F; Sañudo, J R; Arrazola, J

    2016-07-01

    is responsible of major variations. PMID:26728989

  8. Effect of the anatomical site on telomere length and pref-1 gene expression in bovine adipose tissues.

    PubMed

    Yamada, Tomoya; Higuchi, Mikito; Nakanishi, Naoto

    2015-08-01

    Adipose tissue growth is associated with preadipocyte proliferation and differentiation. Telomere length is a biological marker for cell proliferation. Preadipocyte factor-1 (pref-1) is specifically expressed in preadipocytes and acts as a molecular gatekeeper of adipogenesis. In the present study, we investigated the fat depot-specific differences in telomere length and pref-1 gene expression in various anatomical sites (subcutaneous, intramuscular and visceral) of fattening Wagyu cattle. Visceral adipose tissue expressed higher pref-1 mRNA than did subcutaneous and intramuscular adipose tissues. The telomere length in visceral adipose tissue tended to be longer than that of subcutaneous and intramuscular adipose tissues. The telomere length of adipose tissue was not associated with adipocyte size from three anatomical sites. No significant correlation was found between the pref-1 mRNA level and the subcutaneous adipocyte size. In contrast, the pref-1 mRNA level was negatively correlated with the intramuscular and visceral adipocyte size. These results suggest that anatomical sites of adipose tissue affect the telomere length and expression pattern of the pref-1 gene in a fat depot-specific manner. PMID:26067555

  9. Evaluation of Anatomical and Functional Hip Joint Center Methods: The Effects of Activity Type, Gender, and Proximal Reference Segment.

    PubMed

    McGibbon, C A; Fowler, J; Chase, S; Steeves, K; Landry, J; Mohamed, A

    2016-01-01

    Accurate hip joint center (HJC) location is critical when studying hip joint biomechanics. The HJC is often determined from anatomical methods, but functional methods are becoming increasingly popular. Several studies have examined these methods using simulations and in vivo gait data, but none has studied high-range of motion activities, such a chair rise, nor has HJC prediction been compared between males and females. Furthermore, anterior superior iliac spine (ASIS) marker visibility during chair rise can be problematic, requiring a sacral cluster as an alternative proximal segment; but functional HJC has not been explored using this approach. For this study, the quality of HJC measurement was based on the joint gap error (JGE), which is the difference in global HJC between proximal and distal reference segments. The aims of the present study were to: (1) determine if JGE varies between pelvic and sacral referenced HJC for functional and anatomical methods, (2) investigate which functional calibration motion results in the lowest JGE and if the JGE varies depending on movement type (gait versus chair rise) and gender, and (3) assess whether the functional HJC calibration results in lower JGE than commonly used anatomical approaches and if it varies with movement type and gender. Data were collected on 39 healthy adults (19 males and 20 females) aged 14-50 yr old. Participants performed four hip "calibration" tests (arc, cross, star, and star-arc), as well as gait and chair rise (activities of daily living (ADL)). Two common anatomical methods were used to estimate HJC and were compared to HJC computed using a published functional method with the calibration motions above, when using pelvis or sacral cluster as the proximal reference. For ADL trials, functional methods resulted in lower JGE (12-19 mm) compared to anatomical methods (13-34 mm). It was also found that women had significantly higher JGE compared to men and JGE was significantly higher for

  10. Assessing the effectiveness of 30% sodium chloride aqueous solution for the preservation of fixed anatomical specimens: a 5-year follow-up study

    PubMed Central

    de Oliveira, Fabrício Singaretti

    2014-01-01

    Anatomical specimens used in human or veterinary anatomy laboratories are usually prepared with formaldehyde (a cancerous and teratogenic substance), glycerin (an expensive and viscous fluid), or ethanol (which is flammable). This research aimed to verify the viability of an aqueous 30% sodium chloride solution for preservation of anatomical specimens previously fixed with formaldehyde. Anatomical specimens of ruminant, carnivorous, equine, swine and birds were used. All were previously fixed with an aqueous 20% formaldehyde solution and held for 7 days in a 10% aqueous solution of the same active ingredient. During the first phase of the experiment, small specimens of animal tissue previously fixed in formaldehyde were distributed in vials with different concentrations of formaldehyde, with or without 30% sodium chloride solution, a group containing only 30% sodium chloride, and a control group containing only water. During this phase, no contamination was observed in any specimen containing 30% sodium chloride solution, whether alone or in combination with different concentrations of formaldehyde. In the second phase of the experiment, the 30% sodium chloride solution, found to be optimal in the first phase of the experiment, was tested for its long-term preservation properties. For a period of 5 years, the preserved specimens were evaluated three times a week for visual contamination, odors, and changes in color and texture. There was no visual contamination or decay found in any specimen. Furthermore, no strange odors, or changes in color or softness were noted. The 30% sodium chloride solution was determined to be effective in the preservation of anatomic specimens previously fixed in formaldehyde. PMID:24762210

  11. Variation in fracture zone rigidity by dynamic effects

    NASA Astrophysics Data System (ADS)

    Spivak, A. A.; Khazins, V. M.

    2013-03-01

    The coefficient of normal rigidity of different-order fault zones was evaluated from seismic data. The crust tectonic faults were shown to be dynamic systems and nonstatic. Specifically, this is manifested in the variability of their rigidity with time. The value of the rigidity of fault zones varies in time with periods of 13-15 days, 27-32 days, and around 1 year. Here, the coefficient of normal rigidity of different-order fault zones can vary by 1.3 (semimonthly variations) 1.5 (monthly variations), and 2.5 times (annual variations), respectively. These variations are most likely governed by the rate and intensity of the transformation of matter of fault zones and, as a consequence, the variations in their mechanical properties under tidal conditions. Dynamic effects like seismoexplosive waves lead to a reduction in the rigidity of fault zones by 5-50% depending on the amplitude of the compression wave.

  12. Fiber post techniques for anatomical root variations.

    PubMed

    Boksman, Leendert; Hepburn, Alejandro Bertoldi; Kogan, Enrique; Friedman, Manny; de Rijk, Waldemar

    2011-05-01

    In contemporary dental practice, there is no remaining reason to use metallic posts, custom or prefabricated. Many cases that several years ago would have required a retentive post will not require that post today, because of the many improvements in bonding agents and composite resin restoratives. However, in cases where less than 50% of coronal tooth structure remains--or in other cases wherein the judgment of the clinician a post is indicated--there are now aesthetic, non-corrosive, fracture resistant and radiopaque alternatives for all varieties that save time and money without compromise. Their most compelling advantage, regardless of the geometry or amount of residual tooth structure, is the protection from root fracture that a low modulus restoration provides. In selecting the materials (posts, resins) for these techniques, the dentist is advised not to cut corners, and to seek the strongest and most radiopaque products available. PMID:21650123

  13. Dielectric Variation in Paper and its Effect on Electrophotography

    NASA Astrophysics Data System (ADS)

    Provatas, Nikolas; Cassidy, Andrew; Inuoe, Mitsuo

    2002-03-01

    We examine the effect of dielectric variations in paper on the process of electrophotography (e.g. Xerography). We present experiments showing that the two-point desnity-density correlation function of the distribution of certain inorganic paper additives exhibits the same length scales as the distribution of solid toner transfered to paper by after printing. Mumerical simulations of the electrostatic transfer forces associated with electrophotography show that spatial fluctuations of inorganic additives in paper, as well as paper thickness variations, create commensurate fluctuations of the effective dielectric. This in turn leads to variations in the associated electrostatic toner-transfer force. A frequency response analysis further reveals that longer length scale dielectric variations cause symptotically larger amplitude fluctuations of the transfer field. These results are discussed in the context of paper performance as a printing medium.

  14. Effect of critical dimension variation on SAW correlator energy.

    SciTech Connect

    Skinner, Jack L.

    2005-04-01

    The effect of critical dimension (CD) variation and metallization ratio on the efficiency of energy conversion of a surface acoustic wave (SAW) correlator is examined. We find that a 10% variation in the width of finger electrodes predicts only a 1% decrease in the efficiency of energy conversion. Furthermore, our model predicts that a metallization ratio of 0.74 represents an optimum value for energy extraction from the SAW by the interdigitated transducer (IDT).

  15. Effects of Zonal Wind on Stratospheric Ozone Variations over Nigeria

    NASA Astrophysics Data System (ADS)

    Chidinma Okoro, Eucharia,

    2016-07-01

    The effects of zonal wind on stratospheric ozone variation over Nigeria have been studied. The areas covered in this study include; Maiduguri, Ikeja, Port-Harcourt, Calabar, Makurdi, Ilorin, Akure, Yola, Minna, Jos, Kano and Enugu in Nigeria, from 1986 to 2008. Zonal wind was computed from the iso-velocity map employing MATLAB software. The mean monthly variations of AAM and LOD at pressure levels of 20, 30 and 50 mb in the atmosphere depict a trend of maximum amplitude between April and September, and minimum amplitude between December and March. The trend observed in seasonal variation of O3 column data in the low latitude had maximum amount from May through August and minimum values from December through February. The mean monthly maximum O3 concentrations was found to be 284.70 Du (Kano) occurring in May 1989 while, an average monthly minimum O3 concentration was found to be 235.60 Du (Port-Harcourt and Calabar) occurring in January 1998. It has been established in this study that, the variation in atmospheric angular momentum (AAM) caused by variation of the universal time or length of day (LOD) transfer ozone (O3) by means of zonal wind from the upper troposphere to the lower stratosphere in the stations understudy. The strong effect of the pressure levels of the atmosphere on O3 variation could be attributed to its effect on the AAM and LOD. Variation in the LOD is significant in the tropics, suggesting that, the effects of the extra-tropical suction pump (ETSP) action is not the only driver responsible for O3 transportation from the tropics to extra-tropical zones. Consequently, these findings lead to a deduction that weather pattern alteration observed due to these changes could lead to climate change. Keywords: ozone variations; dynamical processes; harmattan wind; ETSP; and climatic variability

  16. Effects of the Variation in Brain Tissue Mechanical Properties on the Intracranial Response of a 6-Year-Old Child

    PubMed Central

    Cui, Shihai; Li, Haiyan; Li, Xiangnan; Ruan, Jesse

    2015-01-01

    Brain tissue mechanical properties are of importance to investigate child head injury using finite element (FE) method. However, these properties used in child head FE model normally vary in a large range in published literatures because of the insufficient child cadaver experiments. In this work, a head FE model with detailed anatomical structures is developed from the computed tomography (CT) data of a 6-year-old healthy child head. The effects of brain tissue mechanical properties on traumatic brain response are also analyzed by reconstruction of a head impact on engine hood according to Euro-NCAP testing regulation using FE method. The result showed that the variations of brain tissue mechanical parameters in linear viscoelastic constitutive model had different influences on the intracranial response. Furthermore, the opposite trend was obtained in the predicted shear stress and shear strain of brain tissues caused by the variations of mentioned parameters. PMID:26495031

  17. Effects of the Variation in Brain Tissue Mechanical Properties on the Intracranial Response of a 6-Year-Old Child.

    PubMed

    Cui, Shihai; Li, Haiyan; Li, Xiangnan; Ruan, Jesse

    2015-01-01

    Brain tissue mechanical properties are of importance to investigate child head injury using finite element (FE) method. However, these properties used in child head FE model normally vary in a large range in published literatures because of the insufficient child cadaver experiments. In this work, a head FE model with detailed anatomical structures is developed from the computed tomography (CT) data of a 6-year-old healthy child head. The effects of brain tissue mechanical properties on traumatic brain response are also analyzed by reconstruction of a head impact on engine hood according to Euro-NCAP testing regulation using FE method. The result showed that the variations of brain tissue mechanical parameters in linear viscoelastic constitutive model had different influences on the intracranial response. Furthermore, the opposite trend was obtained in the predicted shear stress and shear strain of brain tissues caused by the variations of mentioned parameters. PMID:26495031

  18. Ecophysiological and Anatomical Mechanisms behind the Nurse Effect: Which Are More Important? A Multivariate Approach for Cactus Seedlings

    PubMed Central

    Delgado-Sánchez, Pablo; Yáñez-Espinosa, Laura; Jiménez-Bremont, Juan Francisco; Chapa-Vargas, Leonardo; Flores, Joel

    2013-01-01

    Background Cacti establish mostly occurs under the canopy of nurse plants which provide a less stressful micro-environment, although mechanisms underlying this process are unknown. The impact of the combination of light and watering treatments on Opuntia streptacantha (Cactaceae) seedlings was examined. Methods/Principal Findings Ecophysiological [titratable acidity, osmotic potential (‘solute potential’, Ψs), relative growth rate (RGR) and their components (NAR, SLA, and LWR)], anatomical (chloroplast density, chloroplast frequency, and cell area), and environmental [photosynthetic photon flux density (PPFD) and air temperature] sets of variables were analyzed, assessing relationships between them and measuring the intensity of the relationships. Three harvests were carried out at days 15, 30, and 45. Ψs and acidity content were the most important responses for seedling establishment. The main anatomical and environmental variables were chloroplast density and water availability, respectively. Opuntia streptacantha seedlings establish better in the shade-watering treatment, due to higher Ψs and acidity, unaffected chloroplasts, and lower PPFD. In addition, the chloroplasts of cells under high-light and non-watering treatment were clumped closer to the center of the cytosol than those under shade-drought, to avoid photoinhibition and/or to better distribute or utilize the penetrating light in the green plant tissue. Conclusions Opuntia seedlings grow better under the shade, although they can tolerate drought in open spaces by increasing and moving chloroplasts and avoiding drastic decreases in their Ψs. This tolerance could have important implications for predicting the impact of climate change on natural desert regeneration, as well as for planning reforestation-afforestation practices, and rural land uses. PMID:24312310

  19. Seismic reflectivity effects from seasonal seafloor temperature variation

    NASA Astrophysics Data System (ADS)

    Wood, Warren T.; Martin, Kylara M.; Jung, Wooyeol; Sample, John

    2014-10-01

    The effects of seasonal temperature variation on sound speed contrasts at the seafloor are usually considered negligible in the analysis of seismic data but may be significant at large incidence angles (offsets) important for inversion of sediment elastic properties, or long-range acoustic transmission. In coastal areas, the maximum annual seafloor temperature variation can be several degrees Celsius or more, corresponding to a sound speed variation of 30 m/s or more. Thermal pulses propagate via conduction several meters into the seafloor resulting in a damped quasi-sinusoidal temperature profile with predictable wave number characteristics. The oscillating seasonal and spatial character of this signal creates a time- and frequency-dependent effect on the elastic seafloor reflectivity. Results of numerical simulations show that the expected temperature profile for most sediment types and porosities will have the strongest affect on frequencies between about 60 and 600 Hz, at incidence angles greater than about 50°.

  20. The effect of implantation orientation of a bileaflet mechanical heart valve on kinematics and hemodynamics in an anatomic aorta.

    PubMed

    Borazjani, Iman; Sotiropoulos, Fotis

    2010-11-01

    We carry out three-dimensional high-resolution numerical simulations of a bileaflet mechanical heart valve under physiologic pulsatile flow conditions implanted at different orientations in an anatomic aorta obtained from magnetic resonance imaging (MRI) of a volunteer. We use the extensively validated for heart valve flow curvilinear-immersed boundary (CURVIB) fluid-structure interaction (FSI) solver in which the empty aorta is discretized with a curvilinear, aorta-conforming grid while the valve is handled as an immersed boundary. The motion of the valve leaflets are calculated through a strongly coupled FSI algorithm implemented in conjunction with the Aitken convergence acceleration technique. We perform simulations for three valve orientations, which differ from each other by 45 deg and compare the results in terms of leaflet motion and flow field. We show that the valve implanted symmetrically relative to the symmetry plane of the ascending aorta curvature exhibits the smallest overall asymmetry in the motion of its two leaflets and lowest rebound during closure. Consequently, we hypothesize that this orientation is beneficial to reduce the chance of intermittent regurgitation. Furthermore, we find that the valve orientation does not significantly affect the shear stress distribution in the aortic lumen, which is in agreement with previous studies. PMID:21034146

  1. The Effect of Implantation Orientation of a Bileaflet Mechanical Heart Valve on Kinematics and Hemodynamics in an Anatomic Aorta

    PubMed Central

    Borazjani, Iman; Sotiropoulos, Fotis

    2011-01-01

    We carry out three-dimensional high-resolution numerical simulations of a bileaflet mechanical heart valve under physiologic pulsatile flow conditions implanted at different orientations in an anatomic aorta obtained from magnetic resonance imaging (MRI) of a volunteer. We use the extensively validated for heart valve flow curvilinear-immersed boundary (CURVIB) fluid-structure interaction (FSI) solver in which the empty aorta is discretized with a curvilinear, aorta-conforming grid while the valve is handled as an immersed boundary. The motion of the valve leaflets are calculated through a strongly coupled FSI algorithm implemented in conjunction with the Aitken convergence acceleration technique. We perform simulations for three valve orientations, which differ from each other by 45 deg and compare the results in terms of leaflet motion and flow field. We show that the valve implanted symmetrically relative to the symmetry plane of the ascending aorta curvature exhibits the smallest overall asymmetry in the motion of its two leaflets and lowest rebound during closure. Consequently, we hypothesize that this orientation is beneficial to reduce the chance of intermittent regurgitation. Furthermore, we find that the valve orientation does not significantly affect the shear stress distribution in the aortic lumen, which is in agreement with previous studies. PMID:21034146

  2. Variations in effective elastic thickness of the North American lithosphere

    NASA Technical Reports Server (NTRS)

    Bechtel, Timothy D.; Forsyth, Donald W.; Sharpton, Virgil L.; Grieve, Richard A. F.

    1990-01-01

    A technique for estimating flexural rigidity that is not limited to sedimentary basins is used here to map variations in the effective elastic thickness of the North American lithosphere. The effective elastic thickness ranges from a minimum of about 4 km in the Basin and Range Province to more than 100 km in the Precambrian core of the continent. This finding supports the idea that flexural rigidity has increased with time since the last thermal event.

  3. Reference Man anatomical model

    SciTech Connect

    Cristy, M.

    1994-10-01

    The 70-kg Standard Man or Reference Man has been used in physiological models since at least the 1920s to represent adult males. It came into use in radiation protection in the late 1940s and was developed extensively during the 1950s and used by the International Commission on Radiological Protection (ICRP) in its Publication 2 in 1959. The current Reference Man for Purposes of Radiation Protection is a monumental book published in 1975 by the ICRP as ICRP Publication 23. It has a wealth of information useful for radiation dosimetry, including anatomical and physiological data, gross and elemental composition of the body and organs and tissues of the body. The anatomical data includes specified reference values for an adult male and an adult female. Other reference values are primarily for the adult male. The anatomical data include much data on fetuses and children, although reference values are not established. There is an ICRP task group currently working on revising selected parts of the Reference Man document.

  4. The effect of epistasis on sexually antagonistic genetic variation

    PubMed Central

    Arnqvist, Göran; Vellnow, Nikolas; Rowe, Locke

    2014-01-01

    There is increasing evidence of segregating sexually antagonistic (SA) genetic variation for fitness in laboratory and wild populations, yet the conditions for the maintenance of such variation can be restrictive. Epistatic interactions between genes can contribute to the maintenance of genetic variance in fitness and we suggest that epistasis between SA genes should be pervasive. Here, we explore its effect on SA genetic variation in fitness using a two locus model with negative epistasis. Our results demonstrate that epistasis often increases the parameter space showing polymorphism for SA loci. This is because selection in one locus is affected by allele frequencies at the other, which can act to balance net selection in males and females. Increased linkage between SA loci had more marginal effects. We also show that under some conditions, large portions of the parameter space evolve to a state where male benefit alleles are fixed at one locus and female benefit alleles at the other. This novel effect of epistasis on SA loci, which we term the ‘equity effect’, may have important effects on population differentiation and may contribute to speciation. More generally, these results support the suggestion that epistasis contributes to population divergence. PMID:24870040

  5. Variation of force amplitude and its effects on local fatigue.

    PubMed

    Yung, Marcus; Mathiassen, Svend Erik; Wells, Richard P

    2012-11-01

    Trends in industry are leaning toward stereotyped jobs with low workloads. Physical variation is an intervention to reduce fatigue and potentially musculoskeletal disorders in such jobs. Controlled laboratory studies have provided some insight into the effectiveness of physical variation, but very few have been devoted to force variation without muscular rest as a component. This study was undertaken to determine multiple physiological responses to five isometric elbow extension protocols with the same mean amplitude (15% maximum voluntary contraction, MVC), cycle time (6 s), and duty cycle (50 %). Sustained (15 %Sus) and intermittent contractions including zero force (0-30 %Int) differed significantly in 19 of 27 response variables. Contractions varying by half the mean force (7.5-22.5 %Int) led to 8 and 7 measured responses that were significantly different from 0-30 %Int and 15 %Sus, respectively. A sinusoidal condition (0-30 %Sine) resulted in 2 variables that were significantly different from 0-30 %Int, and 16 different from 15 %Sus. Finally, ten response variables suggested that varying forces with 1 % as the lower contraction level was significantly less fatiguing than 15 %Sus, while no responses were significantly different from 0-30 %Int. Sustained contractions led to decreased twitch force 24-h post-exercise, whereas recovery was complete within 60 min after intermittent contractions. This suggests that time-varying force may be a useful intervention to reduce local fatigue in workers performing low-load tasks, and also that rest per se did not seem to cause any extraordinary effects beyond those predictable from the force variation amplitude. PMID:22407330

  6. Environmental Variation and Cohort Effects in an Antarctic Predator

    NASA Technical Reports Server (NTRS)

    Garrott, Robert A.; Rotella, Jay J.; Siniff, Donald B.; Parkinson, Claire L.; Stauffer, Glenn E.

    2011-01-01

    Understanding the potential influence of environmental variation experienced by animals during early stages of development on their subsequent demographic performance can contribute to our understanding of population processes and aid in predicting impacts of global climate change on ecosystem functioning. Using data from 4,178 tagged female Weddell seal pups born into 20 different cohorts, and 30 years of observations of the tagged seals, we evaluated the hypothesis that environmental conditions experienced by young seals, either indirectly through maternal effects and/or directly during the initial period of juvenile nutritional independence, have long-term effects on individual demographic performance. We documented an approximately 3-fold difference in the proportion of each cohort that returned to the pupping colonies and produced a pup within the first 10 years after birth. We found only weak evidence for a correlation between annual environmental conditions during the juvenile-independence period and cohort recruitment probability. Instead, the data strongly supported an association between cohort recruitment probability and the regional extent of sea ice experienced by the mother during the winter the pup was in utero. We suggest that inter-annual variation in winter sea-ice extent influences the foraging success of pregnant seals by moderating the regional abundance of competing predators that cannot occupy areas of consolidated sea ice, and by directly influencing the abundance of mid-trophic prey species that are sea-ice obligates. We hypothesize that this environmentally-induced variation in maternal nutrition dictates the extent of maternal energetic investment in offspring, resulting in cohort variation in mean size of pups at weaning which, in turn, contributes to an individual?s phenotype and its ultimate fitness. These linkages between sea ice and trophic dynamics, combined with demonstrated and predicted changes in the duration and extent of sea

  7. Antidepressant-like behavioral, anatomical, and biochemical effects of petroleum ether extract from maca (Lepidium meyenii) in mice exposed to chronic unpredictable mild stress.

    PubMed

    Ai, Zhong; Cheng, Ai-Fang; Yu, Yuan-Tao; Yu, Long-Jiang; Jin, Wenwen

    2014-05-01

    Maca has been consumed as a medical food in Peru for thousands of years, and exerts anxiolytic and antidepressant effects. Our present study aimed to evaluate the behavior and anatomical and biochemical effects of petroleum ether extract from maca (ME) in the chronic unpredictable mild stress (CUMS) model of depression in mice. Three different doses of maca extract (125, 250, and 500 mg/kg) were orally administrated in the six-week CUMS procedure. Fluoxetine (10 mg/kg) was used as a positive control drug. Maca extract (250 and 500 mg/kg) significantly decreased the duration of immobility time in the tail suspension test. After treatment with maca extract (250 and 500 mg/kg), the granule cell layer in the dentate gyrus appeared thicker. Maca extract (250 and 500 mg/kg) also induced a significant reduction in corticosterone levels in mouse serum. In mouse brain tissue, after six weeks of treatment, noradrenaline and dopamine levels were increased by maca extract, and the activity of reactive oxygen species was significantly inhibited. Serotonin levels were not significantly altered. These results demonstrated that maca extract (250 and 500 mg/kg) showed antidepressant-like effects and was related to the activation of both noradrenergic and dopaminergic systems, as well as attenuation of oxidative stress in mouse brain. PMID:24730393

  8. Antidepressant-Like Behavioral, Anatomical, and Biochemical Effects of Petroleum Ether Extract from Maca (Lepidium meyenii) in Mice Exposed to Chronic Unpredictable Mild Stress

    PubMed Central

    Ai, Zhong; Cheng, Ai-Fang; Yu, Yuan-Tao; Yu, Long-Jiang

    2014-01-01

    Abstract Maca has been consumed as a medical food in Peru for thousands of years, and exerts anxiolytic and antidepressant effects. Our present study aimed to evaluate the behavior and anatomical and biochemical effects of petroleum ether extract from maca (ME) in the chronic unpredictable mild stress (CUMS) model of depression in mice. Three different doses of maca extract (125, 250, and 500 mg/kg) were orally administrated in the six-week CUMS procedure. Fluoxetine (10 mg/kg) was used as a positive control drug. Maca extract (250 and 500 mg/kg) significantly decreased the duration of immobility time in the tail suspension test. After treatment with maca extract (250 and 500 mg/kg), the granule cell layer in the dentate gyrus appeared thicker. Maca extract (250 and 500 mg/kg) also induced a significant reduction in corticosterone levels in mouse serum. In mouse brain tissue, after six weeks of treatment, noradrenaline and dopamine levels were increased by maca extract, and the activity of reactive oxygen species was significantly inhibited. Serotonin levels were not significantly altered. These results demonstrated that maca extract (250 and 500 mg/kg) showed antidepressant-like effects and was related to the activation of both noradrenergic and dopaminergic systems, as well as attenuation of oxidative stress in mouse brain. PMID:24730393

  9. Occipital neuralgia: anatomic considerations.

    PubMed

    Cesmebasi, Alper; Muhleman, Mitchel A; Hulsberg, Paul; Gielecki, Jerzy; Matusz, Petru; Tubbs, R Shane; Loukas, Marios

    2015-01-01

    Occipital neuralgia is a debilitating disorder first described in 1821 as recurrent headaches localized in the occipital region. Other symptoms that have been associated with this condition include paroxysmal burning and aching pain in the distribution of the greater, lesser, or third occipital nerves. Several etiologies have been identified in the cause of occipital neuralgia and include, but are not limited to, trauma, fibrositis, myositis, fracture of the atlas, and compression of the C-2 nerve root, C1-2 arthrosis syndrome, atlantoaxial lateral mass osteoarthritis, hypertrophic cervical pachymeningitis, cervical cord tumor, Chiari malformation, and neurosyphilis. The management of occipital neuralgia can include conservative approaches and/or surgical interventions. Occipital neuralgia is a multifactorial problem where multiple anatomic areas/structures may be involved with this pathology. A review of these etiologies may provide guidance in better understanding occipital neuralgia. PMID:25244129

  10. Time variation of effective climate sensitivity in GCMs

    NASA Astrophysics Data System (ADS)

    Williams, K. D.; Ingram, W. J.; Gregory, J. M.

    2009-04-01

    Effective climate sensitivity is often assumed to be constant (if uncertain), but some previous studies of General Circulation Model (GCM) simulations have found it varying as the simulation progresses. This complicates the fitting of simple models to such simulations, as well as having implications for the estimation of climate sensitivity from observations. This study examines the evolution of the feedbacks determining the climate sensitivity in GCMs submitted to the Coupled Model Intercomparison Project. Apparent centennial-timescale variations of effective climate sensitivity during stabilisation to a forcing can be considered an artefact of using conventional forcings which only allow for instantaneous effects and stratospheric adjustment. If the forcing is adjusted for processes occurring on timescales which are short compared to the climate stabilisation timescale then there is little centennial timescale evolution of effective climate sensitivity in any of the GCMs. We suggest that much of the apparent variation in effective climate sensitivity identified in previous studies is actually due to the comparatively fast forcing adjustment. Persistent differences are found in the strength of the feedbacks between the coupled atmosphere - ocean (AO) versions and their atmosphere - mixed-layer ocean (AML) counterparts, (the latter are often assumed to give the equilibrium climate sensitivity of the AOGCM). The AML model can typically only estimate the equilibrium climate sensitivity of the parallel AO version to within about 0.5K. The adjustment to the forcing to account for comparatively fast processes varies in magnitude and sign between GCMs, as well as differing between AO and AML versions of the same model. There is evidence from one AOGCM that the forcing adjustment may take a couple of decades, with implications for observationally based estimates of equilibrium climate sensitivity. We suggest that at least some of the spread in 21st century global

  11. Racial Variation in the Effect of Incarceration on Neighborhood Attainment

    PubMed Central

    Massoglia, Michael; Firebaugh, Glenn; Warner, Cody

    2013-01-01

    Each year, more than 700,000 convicted offenders are released from prison and reenter neighborhoods across the country. Prior studies have found that minority ex-inmates tend to reside in more disadvantaged neighborhoods than do white ex-inmates. However, because these studies do not control for pre-prison neighborhood conditions, we do not know how much (if any) of this racial variation is due to arrest and incarceration, or if these observed findings simply reflect existing racial residential inequality. Using a nationally representative dataset that tracks individuals over time, we find that only whites live in significantly more disadvantaged neighborhoods after prison than prior to prison. Blacks and Hispanics do not, nor do all groups (whites, blacks, and Hispanics) as a whole live in worse neighborhoods after prison. We attribute this racial variation in the effect of incarceration to the high degree of racial neighborhood inequality in the United States: because white offenders generally come from much better neighborhoods, they have much more to lose from a prison spell. In addition to advancing our understanding of the social consequences of the expansion of the prison population, these findings demonstrate the importance of controlling for preprison characteristics when investigating the effects of incarceration on residential outcomes. PMID:24367134

  12. Effective DQE (eDQE) for monoscopic and stereoscopic chest radiography imaging systems with the incorporation of anatomical noise

    SciTech Connect

    Boyce, Sarah J.; Choudhury, Kingshuk Roy; Samei, Ehsan

    2013-09-15

    Purpose: Stereoscopic chest biplane correlation imaging (stereo/BCI) has been proposed as an alternative modality to single view chest x-ray (CXR). The metrics effective modulation transfer function (eMTF), effective normalized noise power spectrum (eNNPS), and effective detective quantum efficiency (eDQE) have been proposed as clinically relevant metrics for assessing clinical system performance taking into consideration the magnification and scatter effects. This study compared the metrics eMTF, eNNPS, eDQE, and detectability index for stereo/BCI and single view CXR under isodose conditions at two magnifications for two anthropomorphic phantoms of differing sizes.Methods: Measurements for the eMTF were taken for two phantom sizes with an opaque edge test device using established techniques. The eNNPS was measured at two isodose conditions for two phantoms using established techniques. The scatter was measured for two phantoms using an established beam stop method. All measurements were also taken at two different magnifications with two phantoms. A geometrical phantom was used for comparison with prior results for CXR although the results for an anatomy free phantom are not expected to vary for BCI.Results: Stereo/BCI resulted in improved metrics compared to single view CXR. Results indicated that magnification can potentially improve the detection performance primarily due to the air gap which reduced scatter by ∼20%. For both phantoms, at isodose, eDQE(0) for stereo/BCI was ∼100 times higher than that for CXR. Magnification at isodose improved eDQE(0) by ∼10 times for stereo/BCI. Increasing the dose did not improve eDQE. The detectability index for stereo/BCI was ∼100 times better than single view CXR for all conditions. The detectability index was also not improved with increased dose.Conclusions: The findings indicate that stereo/BCI with magnification may improve detectability of subtle lung nodules compared to single view CXR. Results were improved

  13. Longitudinal Variations in Stratospheric Ozone: Effects on "Downward Control"

    NASA Astrophysics Data System (ADS)

    Nathan, T. R.; Cordero, E. C.

    2008-12-01

    The wave drag associated with the damping and breaking of vertically propagating planetary waves in the stratosphere has far-reaching consequences for the global circulation and climate. The planetary wave drag (PWD) exerts non-local control over the extratropical stratosphere that manifests as a wave-driven equator- to-pole meridional circulation, termed the Brewer-Dobson circulation (BDC). In the steady state, the BDC can exert "downward control," whereby the body force exerted by the PWD causes a mean meridional circulation and a simultaneous mass adjustment in the surface pressure. Thus any changes in the PWD in the stratosphere will produce a balanced response in the region below. The downward influence exerted by longitudinal variations in stratospheric ozone is examined using a mechanistic chemistry-dynamical model (CDM) of the extratropical atmosphere. The CDM is one-dimensional in height and self-consistently couples dynamics, radiative transfer, and the transport and photochemistry of ozone. The longitudinal variations in ozone induce a zonal-mean body force that affects the residual circulation via the PWD. Under steady-state conditions, for which the "downward control" principle applies, a WKB analysis yields an analytical expression that shows the direct connection between the residual vertical velocity and the transport and photochemistry of ozone. Because the one-dimensional model framework confines the waves to propagate solely in the vertical, a stratospheric reflecting surface is required for the planetary wave-induced ozone heating in the stratosphere to produce non-local changes in that are manifested in the troposphere. These results underscore the importance of longitudinal variations in ozone as a pathway for communicating, via the combined effects of "downward control" and planetary wave reflection, natural and human-caused changes in stratospheric ozone to changes in tropospheric climate.

  14. [Neonatal treatment effect with selective inhibitor of 5-HT recapture on [corrected] the cranium-encephalic anatomic development].

    PubMed

    Magalhães, Carolina Peixoto; de Lima, Luciene Oliveira; da Silva, Matilde Cesiana; Marinho, Sônia Maria Oliveira Cavalcanti; do Nascimento, Elizabeth; da Silva, Cristiano Mendes; de Souza, Sandra Lopes; Manhães-de-Castro, Raul

    2006-12-01

    Neonatal repercussion researched of the serotonin selective recapture inibitor (SSRI) chronic treatment about the somatic growth, of the encephalon and skull. Male rats were divided into groups: control (NaCl) and Cit (10 microL/Kg citalopram 10 mg). In 21 post birth days were measured body weight, side axle , front and rear and skull circle. At 8, 15, 22 days after birth, animals were sacrified for the encephalon withdrawal to evaluate the measurements mentioned above. SSRI use caused body growth deficit, skull and encephalon reduction. The retard is possibly caused by the magnitude change of the trophic serotonin action over the skull-facial morphogenesis, reinforcing the serotoninergic system participation over the somatic and ontogenic growth. The SSRI possible hypophagic effects are not discarded. PMID:17221009

  15. Anatomical effects of dexamethasone intravitreal implant in diabetic macular oedema: a pooled analysis of 3-year phase III trials

    PubMed Central

    Danis, Ronald P; Sadda, Srinivas; Li, Xiao-Yan; Cui, Harry; Hashad, Yehia; Whitcup, Scott M

    2016-01-01

    Background/aim To assess long-term effects of dexamethasone intravitreal implant (DEX implant) monotherapy on retinal morphology in diabetic macular oedema (DME). Methods Two multicentre, masked, phase III studies with identical protocols randomised patients with DME, best-corrected visual acuity of 34–68 Early Treatment Diabetic Retinopathy Study letters and central subfield retinal thickness (CSRT) ≥300 µm to DEX implant 0.7, 0.35 mg or sham procedure. Patients were followed up for 3 years (39 months if treated at month 36), with retreatment allowed at ≥6-month intervals. Patients needing other macular oedema (ME) therapy exited the study. Changes from baseline in CSRT, macular volume and ME grade, area of retinal thickening, macular leakage, macular capillary loss and diabetic retinopathy severity were assessed. Results After 3 years, more eyes treated with DEX implant 0.7 and 0.35 mg than sham showed improvement (although small) in ME grade (p<0.05 vs sham). DEX implant 0.7 mg delayed time to onset of two-step progression in diabetic retinopathy severity by ∼12 months. DEX implant 0.7 and 0.35 mg produced small, non-sustained reductions in macular leakage but had no significant effect on macular capillary loss. Conclusions DEX implant 0.7 or 0.35 mg, administered at ≥6-month intervals over 3 years, produced sustained retinal structural improvement in DME. Trial registration number NCT00168337 and NCT00168389. PMID:26581718

  16. Evaluation of the effect of respiratory and anatomical variables on a Fourier technique for markerless, self-sorted 4D-CBCT

    PubMed Central

    Vergalasova, I.; Cai, J.; Segars, W. P.; Yin, F. F.

    2013-01-01

    A novel technique based on Fourier Transform theory has been developed that directly extracts respiratory information from projections without the use of external surrogates. While the feasibility has been demonstrated with three patients, a more extensive validation is necessary. Therefore, the purpose of this work is to investigate the effects of a variety of respiratory and anatomical scenarios on the performance of the technique with the 4D Digital Extended Cardiac Torso phantom. FT-Phase and FT-Magnitude methods were each applied to identify peak-inspiration projections and quantitatively compared to the gold standard of visual identification. Both methods proved to be robust across the studied scenarios with average differences in respiratory phase<10% and percentage of projections assigned within 10% of the gold standard >90%, when incorporating minor modifications to region-of-interest selection and/or low-frequency location for select cases of diaphragm amplitude and lung percentage in the field-of-view of the projection. Nevertheless, in the instance where one method initially faltered, the other method prevailed and successfully identified peak-inspiration projections. This is promising because it suggests that the two methods provide complementary information to each other. To ensure appropriate clinical adaptation of markerless, self-sorted 4D-CBCT, perhaps an optimal integration of the two methods can be developed. PMID:24061289

  17. Solar UV radiation variations and their stratospheric and climatic effects

    NASA Technical Reports Server (NTRS)

    Donnelly, R. F.; Heath, D. F.

    1985-01-01

    Nimbus-7 SBUV measurements of the short-term solar UV variations caused by solar rotation and active-region evolution have determined the amplitude and wavelength dependence for the active-region component of solar UV variations. Intermediate-term variations lasting several months are associated with rounds of major new active regions. The UV flux stays near the peak value during the current solar cycle variation for more than two years and peaks about two years later than the sunspot number. Nimbus-7 measurements have observed the concurrent stratospheric ozone variations caused by solar UV variations. There is now no doubt that solar UV variations are an important cause of short- and long-term stratospheric variations, but the strength of the coupling to the troposphere and to climate has not yet been proven.

  18. Effects of climate variation on viticulture in Spain

    NASA Astrophysics Data System (ADS)

    Iglesias, Isabel; Nieves Lorenzo, M.; Taboada, Juan J.; Ramos, Alexandre M.

    2015-04-01

    Droughts, floods and extreme weather events (heat-waves, floods and droughts) may cause higher losses to the primary sector. The crops are very dependent on meteorological conditions. In particular, the agricultural sector needs climatic and seasonal forecast that anticipates variations in crop production. Changes in climate could alter crop distribution, and policy-makers working in areas related to climate change should learn about the impact of climate change on crop yields. The aim of this study is to investigate the effect of climate variation on Spanish viticulture. Spain remains the country with the largest area of vineyards of the European Union and the world. The vine is the third extension of cultivation in Spanish, after cereals and olives. The knowledge on influence of changes in temperature and rainfall in the actual context of climate change on grape of wine productivity is necessary to elaborate appropriate adaptation measures to the viticulture sector. The influence of main climate variability patterns on the grape of wine also has been analyzed. In particular, the main variability modes of the North Atlantic area (NAO, EA; EAWR and SCA) and the oscillation modes of the equatorial Pacific will be considered (SOI and NIÑO34). The choice of these modes was motivated by previous work where the influence of these modes on Iberian Peninsula was analyzed.

  19. Epidemiological effects of group size variation in social species

    PubMed Central

    Caillaud, Damien; Craft, Meggan E.; Meyers, Lauren Ancel

    2013-01-01

    Contact patterns in group-structured populations determine the course of infectious disease outbreaks. Network-based models have revealed important connections between group-level contact patterns and the dynamics of epidemics, but these models typically ignore heterogeneities in within-group composition. Here, we analyse a flexible mathematical model of disease transmission in a hierarchically structured wildlife population, and find that increased variation in group size reduces the epidemic threshold, making social animal populations susceptible to a broader range of pathogens. Variation in group size also increases the likelihood of an epidemic for mildly transmissible diseases, but can reduce the likelihood and expected size of an epidemic for highly transmissible diseases. Further, we introduce the concept of epidemiological effective group size, which we define to be the group size of a hypothetical population containing groups of identical size that has the same epidemic threshold as an observed population. Using data from the Serengeti Lion Project, we find that pride-living Serengeti lions are epidemiologically comparable to a homogeneous population with up to 20 per cent larger prides. PMID:23576784

  20. Effects of variations in recharge on groundwater quality

    USGS Publications Warehouse

    Whittemore, D.O.; McGregor, K.M.; Marotz, G.A.

    1989-01-01

    The predominant regional effect of recharge on municipal groundwater quality in Kansas is the dilution of mineralized water in aquifers with relatively shallow water tables. The individual dissolved constituents contributing most to the water-quality variations are sulfate and chloride, and the calcium and sodium accompanying them, which are derived from the dissolution of evaporite minerals within the aquifer or from saline formation water in bedrock underlying the aquifer. The relationship between recharge and groundwater-quality variation can be quantified by associating certain climatic indices, especially the Palmer Drought Index, with quality observations. The response time of the maximum water-quality change relative to the occurrence of drought or substantial recharge ranges from a month to 3 years depending on the aquifer characteristics, and is generally proportional to the saturated thickness and specific yield. The response time is also affected by discharge to and recharge from nearby streams and by the well construction, particularly the placement of the screened interval, and pumping stress. ?? 1989.

  1. a Variational Ground State for the Fractional Quantum Hall Effect.

    NASA Astrophysics Data System (ADS)

    Galejs, Robert Julian

    1987-09-01

    The fractional quantum Hall effect has aroused much interest in recent years. A large portion of the research in this field has centered on the theoretical understanding of the ground state properties of a system of two-dimensional electrons in a perpendicular magnetic field. One of the most successful models for such a system is that of Laughlin, who proposed a trial wavefunction to model the ground state for certain electron densities. The present work examines the ground state of this system variationally for three and four electrons. The ground state was modeled as a sum of Slater determinants composed of one-electron functions from the lowest Landau level. This wavefunction was placed on a disk of neutralizing charge and the coefficients of the determinants varied to minimize the energy. This variational wavefunction may be compared directly with Laughlin's, as well as model densities not described by Laughlin. The energy per electron was found to vary smoothly as a function of filling factor except at discrete points where there was an upward cusp. Downward cusps, as found by other investigators, were not found in this work. In the smooth portions, the wavefunction is incompressible whereas at the cusps, the wavefunction undergoes a drastic change. In the presence of impurities, these upward cusps smooth out and the wavefunction is now charge-density-wave -like near the former location of the cusps. This variation between incompressible and charge-density-wave behavior may give an explanation of the behavior of the Hall plateau widths as a function of impurity concentration. At a filling factor of 1/3 it was found that the Laughlin wavefunction is a very good approximation to the ground state, giving a very large overlap with and only a slightly higher energy than the variational state calculated here. Laughlin's excited states appear to be a good approximation as well, although the details of their charge density may not be. A new class of wavefunctions was

  2. Tracking in anatomic pathology.

    PubMed

    Pantanowitz, Liron; Mackinnon, Alexander C; Sinard, John H

    2013-12-01

    Bar code-based tracking solutions, long present in clinical pathology laboratories, have recently made an appearance in anatomic pathology (AP) laboratories. Tracking of AP "assets" (specimens, blocks, slides) can enhance laboratory efficiency, promote patient safety, and improve patient care. Routing of excess clinical material into research laboratories and biorepositories are other avenues that can benefit from tracking of AP assets. Implementing tracking is not as simple as installing software and turning it on. Not all tracking solutions are alike. Careful analysis of laboratory workflow is needed before implementing tracking to assure that this solution will meet the needs of the laboratory. Such analysis will likely uncover practices that may need to be modified before a tracking system can be deployed. Costs that go beyond simply that of purchasing software will be incurred and need to be considered in the budgeting process. Finally, people, not technology, are the key to assuring quality. Tracking will require significant changes in workflow and an overall change in the culture of the laboratory. Preparation, training, buy-in, and accountability of the people involved are crucial to the success of this process. This article reviews the benefits, available technology, underlying principles, and implementation of tracking solutions for the AP and research laboratory. PMID:23634908

  3. Characterization of surface reflectance variation effects on remote sensing

    NASA Astrophysics Data System (ADS)

    Pearce, W. A.

    1984-03-01

    The use of Monte Carlo radiative transfer codes to simulate the effects on remote sensing in visible and infrared wavelengths of variables which affect classification is examined. These variables include detector viewing angle, atmospheric aerosol size distribution, aerosol vertical and horizontal distribution (e.g., finite clouds), the form of the bidirectional ground reflectance function, and horizontal variability of reflectance type and reflectivity (albedo). These simulations are used to characterize the sensitivity of observables (intensity and polarization) to variations in the underlying physical parameters both to improve algorithms for the removal of atmospheric effects and to identify techniques which can improve classification accuracy. It was necessary to revise and validate the simulation codes (CTRANS, ARTRAN, and the Mie scattering code) to improve efficiency and accommodate a new operational environment, and to build the basic software tools for acquisition and off-line manipulation of simulation results. Initial calculations compare cases in which increasing amounts of aerosol are shifted into the stratosphere, maintaining a constant optical depth. In the case of moderate aerosol optical depth, the effect on the spread function is to scale it linearly as would be expected from a single scattering model. Varying the viewing angle appears to provide the same qualitative effect as modifying the vertical optical depth (for Lambertian ground reflectance).

  4. Micrometoric Impact Effects: Peak Pressure versus Spectral Variation

    NASA Technical Reports Server (NTRS)

    Jensen, Elizabeth; Lederer, S. M.; Wooden, D. H.; Lindsay, S. S.; Keller, L. P.; Cintala, M. J.; Zolensky, M. E.

    2013-01-01

    At the Experimental Impact Laboratory at NASA Johnson Space Center, we have investigated the surface properties of asteroids caused by collisions in the mid-infrared (2.5 to 16 microns) by impacting forsterite and enstatite across a range of velocities (as predicted by the Nice Model) and at varying temperatures. The crystal structure in these minerals can be deformed by the shock wave from the impact as well as sheared into smaller particle sizes. Our current focus is on the differing effects between 2.3 and 2.6 km/sec, as well as the differences between a cold sample at -20C and a room temperature sample at 25C. We find that the spectral variation and crystal deformation varies non-linearly with the peak shock pressure.

  5. Effects of UV-B radiation on anatomical characteristics, phenolic compounds and gene expression of the phenylpropanoid pathway in highbush blueberry leaves.

    PubMed

    Inostroza-Blancheteau, Claudio; Reyes-Díaz, Marjorie; Arellano, Alejandro; Latsague, Mirtha; Acevedo, Patricio; Loyola, Rodrigo; Arce-Johnson, Patricio; Alberdi, Miren

    2014-12-01

    The effects of increased doses of UV-B radiation on anatomical, biochemical and molecular features of leaves of two highbush blueberry (Vaccinium corymbosum L. cv. Brigitta and Bluegold) genotypes were investigated. Plants were grown in a solid substrate and exposed to 0, 0.07, 0.12 and 0.19 Wm(-2) of biologically effective UV-B radiation for up to 72 h. Leaf thickness and the adaxial epidermis thickness fell more than 3-fold in both genotypes at the highest UV-B dose. Moreover, in Bluegold an evident disorganization in the different cell layers was observed at the highest UV-B radiation. A significant decrease in chlorophyll a/b after 6 h in Brigitta under the greater UV-B doses was observed. Anthocyanin and total phenolics were increased, especially at 0.19 Wm(-2), when compared to the control in both genotypes.Chlorogenic acid was the most abundant hydroxycinnamic acid in Brigitta, and was significantly higher (P ≤ 0.05) than in Bluegold leaves. Regarding the expression of phenylpropanoid genes, only the transcription factor VcMYBPA1 showed a significant and sustained induction at higher doses of UV-B radiation in both genotypes compared to the controls. Thus, the reduction of leaf thickness concomitant with a lower lipid peroxidation and rapid enhancement of secondary metabolites, accompanied by a stable induction of the VcMYBPA1 transcription factor suggest a better performance against UV-B radiation of the Brigitta genotype. PMID:25394804

  6. Founder effect: assessment of variation in genetic contributions among founders.

    PubMed

    O'Brien, E; Kerber, R A; Jorde, L B; Rogers, A R

    1994-04-01

    We present a Monte Carlo method for determining the distribution of founders' genetic contributions to descendant cohorts. The simulation of genes through known pedigrees generates the probability distributions of contributed genes in recent cohorts of descendants, their means, and their variances. Genealogical data from three populations are analyzed: the Hutterite population of North America, the island population of Sottunga from the Aland archipelago, and the large Utah Mormon population. Two applications of the Monte Carlo method are presented. First we investigate the relative opportunity for founder effect in the three populations, which have dissimilar pedigree structures and dissimilar disease gene frequencies. Second, we measure the reproductive success of population founders in terms of the number of genes they contribute to a cohort some number of generations descendant and compare the effects of polygyny versus monogamy on reproductive success. The distribution of Hutterite founder contributions describes the context for a classic founder effect. Hutterite founders have a higher probability of leaving no genes in the population (72%) than Sottunga (48%) and Mormon (48%) founders. However, founder genes that survive among Hutterite descendants do so in larger numbers on average than founder genes in the other two populations. Greater variation among monogamous Hutterite founders compared with Mormon polygynous founders demonstrates that polygyny alone does not maximize the variance in reproductive success; other population characteristics are at least as important for determining variability among individuals in their genetic contributions to a gene pool. Our findings make it difficult to appreciate the reproductive advantage of polygyny in the Mormon population. Although the expected gene contributions and their variances were larger for polygynous founders compared with other Mormons, the main effect of polygyny was to increase the probability that

  7. The effect of anatomical modeling on space radiation dose estimates: a comparison of doses for NASA phantoms and the 5th, 50th, and 95th percentile male and female astronauts

    NASA Astrophysics Data System (ADS)

    Bahadori, Amir A.; Van Baalen, Mary; Shavers, Mark R.; Dodge, Charles; Semones, Edward J.; Bolch, Wesley E.

    2011-03-01

    The National Aeronautics and Space Administration (NASA) performs organ dosimetry and risk assessment for astronauts using model-normalized measurements of the radiation fields encountered in space. To determine the radiation fields in an organ or tissue of interest, particle transport calculations are performed using self-shielding distributions generated with the computer program CAMERA to represent the human body. CAMERA mathematically traces linear rays (or path lengths) through the computerized anatomical man (CAM) phantom, a computational stylized model developed in the early 1970s with organ and body profiles modeled using solid shapes and scaled to represent the body morphometry of the 1950 50th percentile (PCTL) Air Force male. With the increasing use of voxel phantoms in medical and health physics, a conversion from a mathematical-based to a voxel-based ray-tracing algorithm is warranted. In this study, the voxel-based ray tracer (VoBRaT) is introduced to ray trace voxel phantoms using a modified version of the algorithm first proposed by Siddon (1985 Med. Phys. 12 252-5). After validation, VoBRAT is used to evaluate variations in body self-shielding distributions for NASA phantoms and six University of Florida (UF) hybrid phantoms, scaled to represent the 5th, 50th, and 95th PCTL male and female astronaut body morphometries, which have changed considerably since the inception of CAM. These body self-shielding distributions are used to generate organ dose equivalents and effective doses for five commonly evaluated space radiation environments. It is found that dosimetric differences among the phantoms are greatest for soft radiation spectra and light vehicular shielding.

  8. Repeated Bout Effect in Muscle-Specific Exercise Variations.

    PubMed

    Zourdos, Michael C; Henning, Paul C; Jo, Edward; Khamoui, Andy V; Lee, Sang-Rok; Park, Young-Min; Naimo, Marshall; Panton, Lynn B; Nosaka, Kazunori; Kim, Jeong-Su

    2015-08-01

    A single bout of unaccustomed exercise confers protective effect against muscle damage from a subsequent bout of similar activity, that is, repeated bout effect (RBE). It remains unknown whether varying muscle-specific exercise between sessions alters the magnitude of the RBE. This study examined the effects of muscle-specific exercise variation between consecutive sessions on the RBE. Twenty untrained males (21 ± 2 years) were assigned to one of 2 groups (n = 10 per group): (a) 2 sessions of incline curls, Fixed Exercise or (b) 1 session of incline curls followed by 1 session of preacher curls, Varied Exercise, with 7 days between sessions. Subjects performed 5 sets of 6 repetitions at ∼50% of maximal isometric elbow flexor strength during each session. Changes in maximal voluntary isometric and isokinetic torque, range of motion, muscle soreness, and serum creatine kinase were measured before, immediately after, and 24, 48, 72, and 96 hours after each exercise session, and the changes were compared between bouts and between groups. There were significant time effects (p < 0.05) for isometric maximal voluntary contraction, concentric maximal voluntary contraction, range of motion, and muscle soreness during sessions 1 and 2 with no between-group differences. Both groups demonstrated a significantly faster recovery of range of motion and soreness to baseline levels after session 2 compared with session 1. Overall, our findings suggest that incline curls conferred a protective effect during subsequent preacher curls in a similar way to repeating incline curls; therefore, the RBE was not exercise specific. PMID:25647658

  9. The Effect of Latitudinal Variation on Shrimp Reproductive Strategies.

    PubMed

    van de Kerk, Madelon; Jones Littles, Chanda; Saucedo, Omar; Lorenzen, Kai

    2016-01-01

    Reproductive strategies comprise the timing and frequency of reproductive events and the number of offspring per reproductive event, depending on factors such as climate conditions. Therefore, species that exhibit plasticity in the allocation of reproductive effort can alter their behavior in response to climate change. Studying how the reproductive strategy of species varies along the latitudinal gradient can help us understand and predict how they will respond to climate change. We investigated the effects of the temporal allocation of reproductive effort on the population size of brown shrimp (Farfantepenaeus aztecus) along a latitudinal gradient. Multiple shrimp species exhibit variation in their reproductive strategies, and given the economic importance of brown shrimp to the commercial fishing sector of the Unites States, changes in the timing of their reproduction could have significant economic and social consequences. We used a stage-based, density-dependent matrix population model tailored to the life history of brown shrimp. Shrimp growth rates and environmental carrying capacity were varied based on the seasonal climate conditions at different latitudes, and we estimated the population size at equilibrium. The length of the growing season increased with decreasing latitude and the reproductive strategy leading to the highest population size changed from one annual birth pulse with high reproductive output to continuous low-output reproduction. Hence, our model confirms the classical paradigm of continuous reproduction at low latitudes, with increased seasonality of the breeding period towards the poles. Our results also demonstrate the potential for variation in climate to affect the optimal reproductive strategy for achieving maximum population sizes. Certainly, understanding these dynamics may inform more comprehensive management strategies for commercially important species like brown shrimp. PMID:27158895

  10. The Effect of Latitudinal Variation on Shrimp Reproductive Strategies

    PubMed Central

    van de Kerk, Madelon; Jones Littles, Chanda; Saucedo, Omar; Lorenzen, Kai

    2016-01-01

    Reproductive strategies comprise the timing and frequency of reproductive events and the number of offspring per reproductive event, depending on factors such as climate conditions. Therefore, species that exhibit plasticity in the allocation of reproductive effort can alter their behavior in response to climate change. Studying how the reproductive strategy of species varies along the latitudinal gradient can help us understand and predict how they will respond to climate change. We investigated the effects of the temporal allocation of reproductive effort on the population size of brown shrimp (Farfantepenaeus aztecus) along a latitudinal gradient. Multiple shrimp species exhibit variation in their reproductive strategies, and given the economic importance of brown shrimp to the commercial fishing sector of the Unites States, changes in the timing of their reproduction could have significant economic and social consequences. We used a stage-based, density-dependent matrix population model tailored to the life history of brown shrimp. Shrimp growth rates and environmental carrying capacity were varied based on the seasonal climate conditions at different latitudes, and we estimated the population size at equilibrium. The length of the growing season increased with decreasing latitude and the reproductive strategy leading to the highest population size changed from one annual birth pulse with high reproductive output to continuous low-output reproduction. Hence, our model confirms the classical paradigm of continuous reproduction at low latitudes, with increased seasonality of the breeding period towards the poles. Our results also demonstrate the potential for variation in climate to affect the optimal reproductive strategy for achieving maximum population sizes. Certainly, understanding these dynamics may inform more comprehensive management strategies for commercially important species like brown shrimp. PMID:27158895

  11. Geodesic estimation for large deformation anatomical shape averaging and interpolation.

    PubMed

    Avants, Brian; Gee, James C

    2004-01-01

    The goal of this research is to promote variational methods for anatomical averaging that operate within the space of the underlying image registration problem. This approach is effective when using the large deformation viscous framework, where linear averaging is not valid, or in the elastic case. The theory behind this novel atlas building algorithm is similar to the traditional pairwise registration problem, but with single image forces replaced by average forces. These group forces drive an average transport ordinary differential equation allowing one to estimate the geodesic that moves an image toward the mean shape configuration. This model gives large deformation atlases that are optimal with respect to the shape manifold as defined by the data and the image registration assumptions. We use the techniques in the large deformation context here, but they also pertain to small deformation atlas construction. Furthermore, a natural, inherently inverse consistent image registration is gained for free, as is a tool for constant arc length geodesic shape interpolation. The geodesic atlas creation algorithm is quantitatively compared to the Euclidean anatomical average to elucidate the need for optimized atlases. The procedures generate improved average representations of highly variable anatomy from distinct populations. PMID:15501083

  12. Anatomic Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Murawski, Christopher D.; Wolf, Megan R.; Araki, Daisuke; Muller, Bart; Tashman, Scott

    2013-01-01

    Anatomic anterior cruciate ligament (ACL) reconstruction is common procedure performed by orthopedic surgeons, particularly in association with sports-related injuries. Whereas traditional reconstruction techniques used a single bundle graft that was typically placed in a non-anatomic position, a renewed interest in anatomy has facilitated the popularization of anatomic reconstruction techniques. Recently, a focus has been placed on individualizing ACL surgery based on each patient’s native anatomical characteristics (e.g., insertion site size, notch size, and shape), thereby dictating the ultimate procedure of choice. As subjective outcome measurements have demonstrated varying outcomes with respect to single- versus double-bundle ACL reconstruction, investigators have turned to more objective techniques, such as in vivo kinematics, as a means of evaluating joint motion and cartilage contact mechanics. Further investigation in this area may yield important information with regard to the potential progression to osteoarthritis after ACL reconstruction, including factors affecting or preventing it. PMID:26069663

  13. Quantitation of maxillary remodeling. 2. Masking of remodeling effects when an "anatomical" method of superimposition is used in the absence of metallic implants.

    PubMed

    Baumrind, S; Korn, E L; Ben-Bassat, Y; West, E E

    1987-06-01

    We report the results of a study aimed at quantifying the differences in the perceived pattern of maxillary remodeling that are observed when different methods are used to superimpose maxillary images in roentgenographic cephalometrics. In a previous article, we reported cumulative changes in the positions of anterior nasal spine (ANS), posterior nasal spine (PNS), and Point A for a sample of 31 subjects with maxillary metallic implants. Measurements had been made on lateral cephalograms taken at annual intervals relative to superimposition on the implants. In the present article, we quantify the differences in the perceived displacement of the same landmarks in the same sample when a standard "anatomical best bit" rule was used in lieu of superimposition on the implants. The anatomical best fit superimposition as herein defined was found in this sample to lose important information on the downward remodeling of the superior surface of the maxilla that had been detected when the implant superimposition was used. In fact, we observed a small artifactual upward displacement of the ANS-PNS line. In the anteroposterior direction, the tendency toward backward displacement of skeletal landmarks through time that had been detected with the implant superimposition was replaced by a small forward displacement of ANS and Point A together with reduced backward displacement of PNS. To the extent that the implant superimposition is to be considered the true and correct one, the anatomical best fit superimposition appears to understate the true downward remodeling of the palate by an average of about 0.3 and 0.4 mm per year, although this value differs at different ages and timepoints. The anatomical best fit superimposition also misses entirely the small mean tendency toward backward remodeling that was observed when the implant superimposition was used. In situations in which there are no implants, clinicians and research workers must necessarily continue to use anatomically

  14. A veterinary digital anatomical database.

    PubMed Central

    Snell, J. R.; Green, R.; Stott, G.; Van Baerle, S.

    1991-01-01

    This paper describes the Veterinary Digital Anatomical Database Project. The purpose of the project is to investigate the construction and use of digitally stored anatomical models. We will be discussing the overall project goals and the results to date. Digital anatomical models are 3 dimensional, solid model representations of normal anatomy. The digital representations are electronically stored and can be manipulated and displayed on a computer graphics workstation. A digital database of anatomical structures can be used in conjunction with gross dissection in teaching normal anatomy to first year students in the professional curriculum. The computer model gives students the opportunity to "discover" relationships between anatomical structures that may have been destroyed or may not be obvious in the gross dissection. By using a digital database, the student will have the ability to view and manipulate anatomical structures in ways that are not available through interactive video disk (IVD). IVD constrains the student to preselected views and sections stored on the disk. Images Figure 1 PMID:1807707

  15. Effects of Spatial Variations in Packing Fraction on Reactor Physics Parameters in Pebble-Bed Reactors

    SciTech Connect

    William K. Terry; A. M. Ougouag; Farzad Rahnema; Michael Scott McKinley

    2003-04-01

    The well-known spatial variation of packing fraction near the outer boundary of a pebble-bed reactor core is cited. The ramifications of this variation are explored with the MCNP computer code. It is found that the variation has negligible effects on the global reactor physics parameters extracted from the MCNP calculations for use in analysis by diffusion-theory codes, but for local reaction rates the effects of the variation are naturally important. Included is some preliminary work in using first-order perturbation theory for estimating the effect of the spatial variation of packing fraction on the core eigenvalue and the fision density distribution.

  16. Characterization and Management of Interfractional Anatomic Changes for Pancreatic Cancer Radiotherapy

    SciTech Connect

    Liu Feng; Erickson, Beth; Peng Cheng; Li, X. Allen

    2012-07-01

    Purpose: To quantitatively characterize interfractional anatomic variations in pancreatic cancer radiotherapy (RT) and to study dosimetric advantages for using an online adaptive replanning scheme to account for these variations. Methods and Materials: Targets and organs at risk (OAR) were delineated by autosegmentation based on daily computed tomography (CT) images acquired using a respiration-gated in-room CT during daily image-guided RT (IGRT) for 10 pancreatic cancer patients. Various parameters, including the maximum overlap ratio (MOR) between the volumes based on planning and daily CTs for a structure, while the overlapping volumes were maximized, were used to quantify the interfractional organ deformation with the intrafractional variations largely excluded. An online adaptive RT (ART) was applied to these daily CTs. To evaluate the dosimetric benefits of ART, the dose distributions from the online ART were compared to those from the repositioning in the current standard IGRT practice. Results: The interfractional anatomic variations, particularly the organ deformation, are significant during pancreas irradiation. For the patients studied, the average MORs of all daily CTs were 80.2%, 61.7%, and 72.2% for pancreatic head, duodenum, and stomach, respectively. The online ART leads to improved dosimetric plan with better target coverage and/or OAR sparing than IGRT repositioning. For the patients studied, the mean V{sub 50.4Gy} (volume covered by 50.4 Gy) for the duodenum was reduced from 43.4% for IGRT to 15.6% for the online ART scheme. Conclusions: The online adaptive RT scheme can effectively account for the significant interfractional anatomic variations observed in pancreas irradiation. The dosimetric advantages with the online ART may enable safe dose escalation in radiation therapy for pancreatic cancer.

  17. Anatomical features of the origin and spread of tumours.

    PubMed Central

    Levene, A. L.

    1978-01-01

    All tumours have certain broad characteristics in common, though they vary widely in their origin, distribution, shape, and mode of spread. The part played by anatomical factors in determining these variations is discussed and the need for the surgeon to bear these factors in mind in diagnosis and treatment is emphasised. Images Fig. 1 Fig. 2 PMID:626470

  18. Understanding the effect of carbon status on stem diameter variations

    PubMed Central

    De Swaef, Tom; Driever, Steven M.; Van Meulebroek, Lieven; Vanhaecke, Lynn; Marcelis, Leo F. M.; Steppe, Kathy

    2013-01-01

    Background Carbon assimilation and leaf-to-fruit sugar transport are, along with plant water status, the driving mechanisms for fruit growth. An integrated comprehension of the plant water and carbon relationships is therefore essential to better understand water and dry matter accumulation. Variations in stem diameter result from an integrated response to plant water and carbon status and are as such a valuable source of information. Methods A mechanistic water flow and storage model was used to relate variations in stem diameter to phloem sugar loading and sugar concentration dynamics in tomato. The simulation results were compared with an independent model, simulating phloem sucrose loading at the leaf level based on photosynthesis and sugar metabolism kinetics and enabled a mechanistic interpretation of the ‘one common assimilate pool’ concept for tomato. Key Results Combining stem diameter variation measurements and mechanistic modelling allowed us to distinguish instantaneous dynamics in the plant water relations and gradual variations in plant carbon status. Additionally, the model combined with stem diameter measurements enabled prediction of dynamic variables which are difficult to measure in a continuous and non-destructive way, such as xylem water potential and phloem hydrostatic potential. Finally, dynamics in phloem sugar loading and sugar concentration were distilled from stem diameter variations. Conclusions Stem diameter variations, when used in mechanistic models, have great potential to continuously monitor and interpret plant water and carbon relations under natural growing conditions. PMID:23186836

  19. Anatomical pathology is dead? Long live anatomical pathology.

    PubMed

    Nicholls, John M; Francis, Glenn D

    2011-10-01

    The standard diagnostic instrument used for over 150 years by anatomical pathologists has been the optical microscope and glass slide. The advent of immunohistochemistry in the routine laboratory in the 1980s, followed by in situ hybridisation in the 1990s, has increased the armamentaria available to the diagnostic pathologist, and this technology has led to changed patient management in a limited number of neoplastic diseases. The first decade of the 21 century has seen an increasing number of publications using proteomic technologies that promise to change disease diagnosis and management, the traditional role of an anatomical pathologist. Despite the plethora of publications on proteomics and pathology, to date there are actually limited data where proteomic technologies do appear to be of greater diagnostic value than the standard histological slide. Though proteomic techniques will become more prevalent in the future, it will need the expertise of an anatomical pathologist to dissect out and validate this added information. PMID:21876472

  20. Anatomical optical coherence tomography: a safe and effective tool for quantitative long-term monitoring of upper airway size and shape

    NASA Astrophysics Data System (ADS)

    Armstrong, J. J.; Becker, S.; McLaughlin, R. A.; Leigh, M. S.; Williamson, J.; Walsh, J. H.; Hillman, D. R.; Eastwood, P. R.; Sampson, D. D.

    2008-02-01

    Anatomical optical coherence tomography (aOCT) is an endoscopic optical technique that enables continuous, quantitative assessment of hollow organ size and shape in three dimensions. It is a powerful alternative to X-ray computed tomography, magnetic resonance imaging, and video endoscopy for the assessment of gross hollow-organ anatomy. This paper reviews our instrument and its application to the upper and lower airway, and includes a number of new results.

  1. Inductive pulsed phase thermography for reducing or enlarging the effect of surface emissivity variation

    NASA Astrophysics Data System (ADS)

    Yang, Ruizhen; He, Yunze; Gao, Bin; Tian, Gui Yun

    2014-11-01

    Emissivity variation introduces illusory temperature inhomogeneity and results in false alarms in infrared thermography, thus, it is important to separate the influence of surface emissivity variation. This letter experimentally demonstrates the advantages of phase information to reduce or enlarge the effect of surface emissivity variation with inductive pulsed phase thermography, where inductive excitation is emissivity-independent and avoids the effect of emissivity variation in heating process. The directly heated area and the indirectly heated area are divided in the phasegrams. The emissivity variation is removed or enlarged perfectly at the specific frequency and defect detectability is improved remarkably.

  2. Effect of Anatomical Modeling on Space Radiation Dose Estimates: A Comparison of Doses for NASA Phantoms and 5th, 50th, and 95th Percentile UF Hybrid Phantoms

    NASA Technical Reports Server (NTRS)

    Bahadori, A.; VanBaalen, M.; Shavers, M.; Semones, E.; Dodge, C.; Bolch, W.

    2010-01-01

    The estimate of absorbed dose to individual organs of a space crewmember is affected by the geometry of the anatomical model of the astronaut used in the radiation transport calculation. For astronaut dosimetry, NASA currently uses the computerized anatomical male (CAM) and computerized anatomical female (CAF) stylized phantoms to represent astronauts in its operational radiation dose analyses. These phantoms are available in one size and in two body positions. In contrast, the UF Hybrid Adult Male and Female (UFHADM and UFHADF) phantoms have organ shapes based on actual CT data. The surfaces of these phantoms are defined by non-uniform rational B-spline surfaces, and are thus flexible in terms of body morphometry and extremity positioning. In this study, UFHADM and UFHADF are scaled to dimensions corresponding to 5th, 50th, and 95th percentile (PCTL) male and female astronauts. A ray-tracing program is written in Visual Basic 2008, which is then used to create areal density maps for dose points corresponding to various organs within the phantoms. The areal density maps, along with appropriate space radiation spectra, are input into the NASA program couplet HZETRN/BRYNTRN, and organ doses are calculated. The areal density maps selected tissues and organs of the 5th, 50th, and 95th PCTL male and female phantoms are presented and compared. In addition, the organ doses for the 5th, 50th, and 95th PCTL male and female phantoms are presented and compared to organ doses for CAM and CAF.

  3. Anatomic pathology laboratory information systems: a review.

    PubMed

    Park, Seung Lyung; Pantanowitz, Liron; Sharma, Gaurav; Parwani, Anil Vasdev

    2012-03-01

    The modern anatomic pathology laboratory depends on a reliable information infrastructure to register specimens, record gross and microscopic findings, regulate laboratory workflow, formulate and sign out report(s), disseminate them to the intended recipients across the whole health system, and support quality assurance measures. This infrastructure is provided by the Anatomical Pathology Laboratory Information Systems (APLIS), which have evolved over decades and now are beginning to support evolving technologies like asset tracking and digital imaging. As digital pathology transitions from "the way of the future" to "the way of the present," the APLIS continues to be one of the key effective enablers of the scope and practice of pathology. In this review, we discuss the evolution, necessary components, architecture and functionality of the APLIS that are crucial to today's practicing pathologist and address the demands of emerging trends on the future APLIS. PMID:22313836

  4. Effects of phonetically-cued talker variation on semantic encoding.

    PubMed

    Sumner, Meghan; Kataoka, Reiko

    2013-12-01

    This study reports equivalence in recognition for variable productions of spoken words that differ greatly in frequency. General American (GA) listeners participated in either a semantic priming or a false-memory task, each with three talkers with different accents: GA, New York City (NYC), and Southern Standard British English (BE). GA/BE induced strong semantic priming and low false recall rates. NYC induced no semantic priming but high false recall rates. These results challenge current theory and illuminate encoding-based differences sensitive to phonetically-cued talker variation. The findings highlight the central role of phonetic variation in the spoken word recognition process. PMID:25669293

  5. Regional variations in the compressive properties of lumbar vertebral trabeculae. Effects of disc degeneration

    SciTech Connect

    Keller, T.S.; Hansson, T.H.; Abram, A.C.; Spengler, D.M.; Panjabi, M.M. )

    1989-09-01

    The compressive mechanical properties of human lumbar vertebral trabeculae were examined on the basis of anatomic origin, bone density, and intervertebral disc properties. Trabecular bone compressive strength and stiffness increased with increasing bone density, the latter proportional to strength and stiffness to the one-half power. Regional variations within each segment were found, the most prevalent differences occurring in regions of bone overlying the disc nucleus in comparison with bone overlying the disc anulus. For normal discs, the ratio of strength of bone overlying the disc nucleus to bone overlying the disc anulus was 1.25, decreasing to 1.0 for moderately degenerated discs. These results suggest that an interdependency of trabecular bone properties and intervertebral disc properties may exist.

  6. Anatomically accurate individual face modeling.

    PubMed

    Zhang, Yu; Prakash, Edmond C; Sung, Eric

    2003-01-01

    This paper presents a new 3D face model of a specific person constructed from the anatomical perspective. By exploiting the laser range data, a 3D facial mesh precisely representing the skin geometry is reconstructed. Based on the geometric facial mesh, we develop a deformable multi-layer skin model. It takes into account the nonlinear stress-strain relationship and dynamically simulates the non-homogenous behavior of the real skin. The face model also incorporates a set of anatomically-motivated facial muscle actuators and underlying skull structure. Lagrangian mechanics governs the facial motion dynamics, dictating the dynamic deformation of facial skin in response to the muscle contraction. PMID:15455936

  7. Pluto's Insolation History: Latitudinal Variations and Effects on Atmospheric Pressure

    NASA Astrophysics Data System (ADS)

    Earle, Alissa M.; Binzel, Richard P.

    2014-11-01

    Since previous insolation modeling in the early 1990’s, new atmospheric pressure data, increased computational power, and the upcoming flyby of the Pluto system by NASA’s New Horizons spacecraft have generated new motivation and increased capabilities for the study of Pluto’s complex long-term (million-years) insolation history. The two primary topics of interest in studying Pluto’s insolation history are the variations in insolation patterns when integrated over different intervals and the evolution of diurnal insolation patterns over the last several decades. We find latitudinal dichotomies when comparing average insolation over timescales of days, decades, centuries, and millennia. Depending on the timescales of volatile migration, some consequences of these insolation patterns may be manifested in the surface features revealed by New Horizons. For any single rotation of Pluto there is a latitude that receives more insolation relative to the others. Often this is the sub-subsolar latitude but it can also be an arctic circle latitude when near-polar regions of Pluto experience the "midnight sun". We define the amount of that greatest insolation value over the course of one rotation as the "maximum diurnal insolation" (MDI). We find that MDI is driven to its highest values when Pluto’s obliquity creates a long arctic summer (or “midnight sun”) beginning just after perihelion. Pluto’s atmospheric pressure, as measured through stellar occultation observations during the past three decades, appears to correlate with Pluto's currently occurring midnight sun as quantified by the MDI parameter. If insolation (as parameterized by the MDI value) is the single dominant factor driving Pluto's atmospheric pressure, this “Midnight Sun Model” predicts that Pluto's maximum atmospheric pressure will be reached in 2017 followed by a steady decline. Pluto's maximum diurnal insolation value begins dropping after 2017 due to two factors: Pluto’s sub-solar point

  8. Heredity vs. Environment: The Effects of Genetic Variation with Age

    ERIC Educational Resources Information Center

    Gourlay, N.

    1978-01-01

    Major problems in the field are presented through a brief review of Burt's work and a critical account of the Hawaiian and British schools of biometrical genetics. The merits and demerits of Christopher Jencks' study are also discussed. There follows an account of the principle of genetic variation with age, a new concept to the…

  9. Global Biomass Variation and its Geodynamic Effects, 1982-1998

    NASA Technical Reports Server (NTRS)

    Rodell, M.; Chao, B. F.; Au, A. Y.; Kimball, J. S.; McDonald, K. C.

    2005-01-01

    Redistribution of mass near Earth's surface alters its rotation, gravity field, and geocenter location. Advanced techniques for measuring these geodetic variations now exist, but the ability to attribute the observed modes to individual Earth system processes has been hampered by a shortage of reliable global data on such processes, especially hydrospheric processes. To address one aspect of this deficiency, 17 yrs of monthly, global maps of vegetation biomass were produced by applying field-based relationships to satellite-derived vegetation type and leaf area index. The seasonal variability of biomass was estimated to be as large as 5 kg m(exp -2). Of this amount, approximately 4 kg m(exp -2) is due to vegetation water storage variations. The time series of maps was used to compute geodetic anomalies, which were then compared with existing geodetic observations as well as the estimated measurement sensitivity of the Gravity Recovery and Climate Experiment (GRACE). For gravity, the seasonal amplitude of biomass variations may be just within GRACE'S limits of detectability, but it is still an order of magnitude smaller than current observation uncertainty using the satellite-laser-ranging technique. The contribution of total biomass variations to seasonal polar motion amplitude is detectable in today's measurement, but it is obscured by contributions from various other sources, some of which are two orders of magnitude larger. The influence on the length of day is below current limits of detectability. Although the nonseasonal geodynamic signals show clear interannual variability, they are too small to be detected.

  10. Population of anatomically variable 4D XCAT adult phantoms for imaging research and optimization

    SciTech Connect

    Segars, W. P.; Bond, Jason; Frush, Jack; Hon, Sylvia; Eckersley, Chris; Samei, E.; Williams, Cameron H.; Frush, D.; Feng Jianqiao; Tward, Daniel J.; Ratnanather, J. T.; Miller, M. I.

    2013-04-15

    as a jumping point from which to create an unlimited number of 3D and 4D variations for imaging research. Conclusions: A population of phantoms that includes a range of anatomical variations representative of the public at large is needed to more closely mimic a clinical study or trial. The series of anatomically variable phantoms developed in this work provide a valuable resource for investigating 3D and 4D imaging devices and the effects of anatomy and motion in imaging. Combined with Monte Carlo simulation programs, the phantoms also provide a valuable tool to investigate patient-specific dose and image quality, and optimization for adults undergoing imaging procedures.

  11. Population of anatomically variable 4D XCAT adult phantoms for imaging research and optimization

    PubMed Central

    Segars, W. P.; Bond, Jason; Frush, Jack; Hon, Sylvia; Eckersley, Chris; Williams, Cameron H.; Feng, Jianqiao; Tward, Daniel J.; Ratnanather, J. T.; Miller, M. I.; Frush, D.; Samei, E.

    2013-01-01

    , serve as a jumping point from which to create an unlimited number of 3D and 4D variations for imaging research. Conclusions: A population of phantoms that includes a range of anatomical variations representative of the public at large is needed to more closely mimic a clinical study or trial. The series of anatomically variable phantoms developed in this work provide a valuable resource for investigating 3D and 4D imaging devices and the effects of anatomy and motion in imaging. Combined with Monte Carlo simulation programs, the phantoms also provide a valuable tool to investigate patient-specific dose and image quality, and optimization for adults undergoing imaging procedures. PMID:23556927

  12. Tectorial Membrane Morphological Variation: Effects upon Stimulus Frequency Otoacoustic Emissions

    PubMed Central

    Bergevin, Christopher; Velenovsky, David S.; Bonine, Kevin E.

    2010-01-01

    The tectorial membrane (TM) is widely believed to play an important role in determining the ear's ability to detect and resolve incoming acoustic information. While it is still unclear precisely what that role is, the TM has been hypothesized to help overcome viscous forces and thereby sharpen mechanical tuning of the sensory cells. Lizards present a unique opportunity to further study the role of the TM given the diverse inner-ear morphological differences across species. Furthermore, stimulus-frequency otoacoustic emissions (SFOAEs), sounds emitted by the ear in response to a tone, noninvasively probe the frequency selectivity of the ear. We report estimates of auditory tuning derived from SFOAEs for 12 different species of lizards with widely varying TM morphology. Despite gross anatomical differences across the species examined herein, low-level SFOAEs were readily measurable in all ears tested, even in non-TM species whose basilar papilla contained as few as 50–60 hair cells. Our measurements generally support theoretical predictions: longer delays/sharper tuning features are found in species with a TM relative to those without. However, SFOAEs from at least one non-TM species (Anolis) with long delays suggest there are likely additional micromechanical factors at play that can directly affect tuning. Additionally, in the one species examined with a continuous TM (Aspidoscelis) where cell-to-cell coupling is presumably relatively stronger, delays were intermediate. This observation appears consistent with recent reports that suggest the TM may play a more complex macromechanical role in the mammalian cochlea via longitudinal energy distribution (and thereby affect tuning). Although significant differences exist between reptilian and mammalian auditory biophysics, understanding lizard OAE generation mechanisms yields significant insight into fundamental principles at work in all vertebrate ears. PMID:20712989

  13. The Effect of Hydroxyapatite Coating on Long-term Results of Total Hip Arthroplasty with Hydroxyapatite-coated Anatomic Femoral Stem

    PubMed Central

    Im, Chae-Hyun; Kim, Dae-Hee; Heo, Ju-Yeong; Jang, Young-Jae

    2014-01-01

    Purpose To evaluate the clinical and radiological results, as well as the survival rate, associated with total hip arthroplasty using a hydroxyapatite (HA)-coated anatomical femoral stem at a follow-up of ≥12 years. Materials and Methods From April 1992 to May 1997, 86 patients (102 hips) underwent total hip arthroplasty with a HA-coated ABG I (Anatomical Benoist Giraud; Howmedica) hip prosthesis. The average age at the time of surgery was 53.4 years and the mean duration of follow-up was 17.1 years (range, 12.1-21.0 years). The Harris hip score (HHS) and radiographic assessments of thigh pain were used to evaluate the clinical results. We observed osteointegration, cortical hypertrophy, reactive line, calcar resorption and osteolysis around the femoral stems. The survival rate of the femoral stems was evaluated by using the span of time to a revision operation for any reasons was defined as the end point. Results The mean HHS was 50.5 preoperatively and 84.2 at the time of last follow-up. Osteolysis only around the HA-coated proximal portion of the femoral stem was observed in 72 hips, cortical hypertrophy all around the distal portion of the femoral stem was observed in 38 hips, and calcar resorption was observed in 44 hips. A reactive line was observed in 13 hips, but was unrelated to component loosening. Stem revision operations were performed in 24 (23%) hips due to osteolysis (14 hips), fracture (5 hips) and infection (5 hips). The femoral stem survival rate was 75% over the mean duration of follow-up. Conclusion Total hip arthroplasty using a HA-coated anatomical femoral stem showed necessitated a high rate of revision operations due to osteolysis around the femoral stem in this long term follow-up study.

  14. Differentiating the impact of anatomic and non-anatomic liver resection on early recurrence in patients with Hepatocellular Carcinoma

    PubMed Central

    2010-01-01

    Background For Hepatocellular Carcinoma (HCC) treated with hepatectomy, the extent of the resection margin remains controversial and data available on its effect on early tumor recurrence are very few and contradictory. The purpose of this study was to compare the impact of the type of resection (anatomic versus non-anatomic) on early intra-hepatic HCC recurrence in patients with solitary HCC and preserved liver function. Methods Among 53 patients with similar clinico-pathologic data who underwent curative liver resection for HCC between 2000 and 2006, 28 patients underwent anatomic resection of at least one liver segment and 25 patients underwent limited resection with a margin of at least 1 cm. Results After a close follow-up period of 24 months, no difference was detected in recurrence rates between the anatomic (35.7%) and the non-anatomic (40%) groups in either univariate (p = 0.74) and multivariate (p = 0.65) analysis. Factors contributing to early recurrence were tumor size (p = 0.012) and tumor stage including vascular invasion (p = 0.009). Conclusion The choice of the type of resection for HCC should be based on the maintenance of adequate hepatic reserve. The type of resection (anatomic vs non-anatomic) was found not to be a risk factor for early tumor recurrence. PMID:20497548

  15. Effects of temporal variation in temperature and density dependence on insect population dynamics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Understanding effects of environmental variation on insect populations is important in light of predictions about increasing future climatic variability. In order to understand the effects of changing environmental variation on population dynamics and life history evolution in insects one would need...

  16. Anatomical modeling of the bronchial tree

    NASA Astrophysics Data System (ADS)

    Hentschel, Gerrit; Klinder, Tobias; Blaffert, Thomas; Bülow, Thomas; Wiemker, Rafael; Lorenz, Cristian

    2010-02-01

    The bronchial tree is of direct clinical importance in the context of respective diseases, such as chronic obstructive pulmonary disease (COPD). It furthermore constitutes a reference structure for object localization in the lungs and it finally provides access to lung tissue in, e.g., bronchoscope based procedures for diagnosis and therapy. This paper presents a comprehensive anatomical model for the bronchial tree, including statistics of position, relative and absolute orientation, length, and radius of 34 bronchial segments, going beyond previously published results. The model has been built from 16 manually annotated CT scans, covering several branching variants. The model is represented as a centerline/tree structure but can also be converted in a surface representation. Possible model applications are either to anatomically label extracted bronchial trees or to improve the tree extraction itself by identifying missing segments or sub-trees, e.g., if located beyond a bronchial stenosis. Bronchial tree labeling is achieved using a naïve Bayesian classifier based on the segment properties contained in the model in combination with tree matching. The tree matching step makes use of branching variations covered by the model. An evaluation of the model has been performed in a leaveone- out manner. In total, 87% of the branches resulting from preceding airway tree segmentation could be correctly labeled. The individualized model enables the detection of missing branches, allowing a targeted search, e.g., a local rerun of the tree-segmentation segmentation.

  17. Effect of seasonal variation of windspeed on energy output

    SciTech Connect

    Jagadeesh, A.

    1983-12-01

    In India the cropping seasons are broadly classified as Kharif (July to October), Rabi (November to February) and Hot Season (March to June). In this paper an attempt is made to know the variation of windspeed and hence the energy output at 10 places based on IMD data (1958-63). This will enable the farmer to chalk out the cropping pattern to reap maximum benefits from the installed windmill.

  18. Planning tiger recovery: Understanding intraspecific variation for effective conservation

    PubMed Central

    Wilting, Andreas; Courtiol, Alexandre; Christiansen, Per; Niedballa, Jürgen; Scharf, Anne K.; Orlando, Ludovic; Balkenhol, Niko; Hofer, Heribert; Kramer-Schadt, Stephanie; Fickel, Jörns; Kitchener, Andrew C.

    2015-01-01

    Although significantly more money is spent on the conservation of tigers than on any other threatened species, today only 3200 to 3600 tigers roam the forests of Asia, occupying only 7% of their historical range. Despite the global significance of and interest in tiger conservation, global approaches to plan tiger recovery are partly impeded by the lack of a consensus on the number of tiger subspecies or management units, because a comprehensive analysis of tiger variation is lacking. We analyzed variation among all nine putative tiger subspecies, using extensive data sets of several traits [morphological (craniodental and pelage), ecological, molecular]. Our analyses revealed little variation and large overlaps in each trait among putative subspecies, and molecular data showed extremely low diversity because of a severe Late Pleistocene population decline. Our results support recognition of only two subspecies: the Sunda tiger, Panthera tigris sondaica, and the continental tiger, Panthera tigris tigris, which consists of two (northern and southern) management units. Conservation management programs, such as captive breeding, reintroduction initiatives, or trans-boundary projects, rely on a durable, consistent characterization of subspecies as taxonomic units, defined by robust multiple lines of scientific evidence rather than single traits or ad hoc descriptions of one or few specimens. Our multiple-trait data set supports a fundamental rethinking of the conventional tiger taxonomy paradigm, which will have profound implications for the management of in situ and ex situ tiger populations and boost conservation efforts by facilitating a pragmatic approach to tiger conservation management worldwide. PMID:26601191

  19. Variation in compound eye structure: effects of diet and family.

    PubMed

    Merry, Justin W; Kemp, Darrell J; Rutowski, Ronald L

    2011-07-01

    Studies of compound eyes have revealed that variation in eye structure can substantially affect visual performance. Here, we investigate the degree to which a stressful rearing environment, which decreases body size, affects the eye phenotype. Full siblings of the Orange Sulphur butterfly, Colias eurytheme, were collected from known parents and split within families among two diet treatments that varied in quality. In both sexes, individuals reared on the high-quality diet had larger eye height and anterior facet diameter, and therefore, by inference, superior vision. However, relative to their reduced body size, individuals reared on low-quality diet had proportionally larger eyes and facets than individuals reared on high-quality diet. We interpret this finding as evidence that butterflies encountering nutritional stress increased proportional investment in eye development to reduce loss of visual performance. We also found significant broad-sense genetic variation underlying eye structure in both males and females, and report novel heritability estimates for eye height and facet diameter. Surprisingly, there was greater genetic variation in eye height among males than among females, despite apparently stronger directional selection on male vision. We discuss the implications of these data for our understanding of eye development and evolution. PMID:21729063

  20. Geomagnetic Variations and Their Possible Effects on System Earth

    NASA Astrophysics Data System (ADS)

    Glassmeier, K.

    2003-12-01

    The Earth magnetic field exhibits a variety of temporal variations with time scales ranging from a few seconds up to millions of years. The most pronounced variation is certainly a polarity transition during which the geomagnetic field strength decays down to about 10-20 % of its current value. A question of immediate interest is whether and in which way System Earth reacts on such a dramatic event. First the magnetosphere changes its size and shape. Due to the decreasing geomagnetic field the magnetopause is located much closer to the surface of the Earth. If the field exhibits strong quadrupole components magnetic reconnection can happen in the northern dayside magnetosphere with the southern hemisphere featuring a closed magnetosphere. Also the magnetotail structure changes drastically. Energetic particle entry occurs not only in dipolar cap regions but over much enlarged areas. As the ionospheric conductivity depends on the geomagnetic field strength first estimates furthermore indicate that externally driven geomagnetic variations are stronger during times of a polarity transition. The weaker field also makes the middle atmosphere much more sensitive to energetic particle events and large natural ozone holes are very likely during polarity transitions as first model calculations indicate.

  1. Planning tiger recovery: Understanding intraspecific variation for effective conservation.

    PubMed

    Wilting, Andreas; Courtiol, Alexandre; Christiansen, Per; Niedballa, Jürgen; Scharf, Anne K; Orlando, Ludovic; Balkenhol, Niko; Hofer, Heribert; Kramer-Schadt, Stephanie; Fickel, Jörns; Kitchener, Andrew C

    2015-06-01

    Although significantly more money is spent on the conservation of tigers than on any other threatened species, today only 3200 to 3600 tigers roam the forests of Asia, occupying only 7% of their historical range. Despite the global significance of and interest in tiger conservation, global approaches to plan tiger recovery are partly impeded by the lack of a consensus on the number of tiger subspecies or management units, because a comprehensive analysis of tiger variation is lacking. We analyzed variation among all nine putative tiger subspecies, using extensive data sets of several traits [morphological (craniodental and pelage), ecological, molecular]. Our analyses revealed little variation and large overlaps in each trait among putative subspecies, and molecular data showed extremely low diversity because of a severe Late Pleistocene population decline. Our results support recognition of only two subspecies: the Sunda tiger, Panthera tigris sondaica, and the continental tiger, Panthera tigris tigris, which consists of two (northern and southern) management units. Conservation management programs, such as captive breeding, reintroduction initiatives, or trans-boundary projects, rely on a durable, consistent characterization of subspecies as taxonomic units, defined by robust multiple lines of scientific evidence rather than single traits or ad hoc descriptions of one or few specimens. Our multiple-trait data set supports a fundamental rethinking of the conventional tiger taxonomy paradigm, which will have profound implications for the management of in situ and ex situ tiger populations and boost conservation efforts by facilitating a pragmatic approach to tiger conservation management worldwide. PMID:26601191

  2. [Anatomical and radiographical studies of the bifid mandibular canal].

    PubMed

    Zhang, Zheng; Fan, Wanting; Zhang, Guozhi

    2016-03-01

    To review the recent progress about the anatomical and radiographical studies of bifid mandibular canal (BMC) in English literature recorded in PubMed from 2006 to 2015 to deepen our understanding of BMC. A BMC is an anatomical variation of the mandibular canal; its occurrence might be a result of the incomplete fusion of mandibular canal during prenatal development. The four types of BMC have been classified according to anatomical location and configuration. Characteristic radiographic features and identifying methods of BMC on panoramic radiography and cone beam computed tomography (CBCT) were described; the visibility of BMC on panoramic radiographs and CBCT images was compared. Clinical value of identifying the location as well as the configuration of BMC for surgical procedures that involve the mandible was discussed. PMID:26980659

  3. Reversed palmaris longus muscle: Anatomical variant – case report and literature review

    PubMed Central

    Murabit, Amera; Gnarra, Maria; Mohamed, Adel

    2013-01-01

    The palmaris longus, a slender fusiform muscle, is especially prone to exhibiting anatomical variance relative to other muscles in the upper extremity. The most frequent anatomical variation is the completely absent palmaris longus, followed by the reversed, duplicated, bifid or hypertrophied palmaris longus muscles. The reversed palmaris longus muscle represents a structure that is tendinous proximally and muscular distally (opposite of the normal palmaris longus). The present report describes a case of reversed palmaris longus muscle, followed by a literature review to illustrate the wide spectrum of anatomical variations in the palmaris longus muscle and their clinical and surgical relevance. PMID:24431941

  4. Reversed palmaris longus muscle: Anatomical variant - case report and literature review.

    PubMed

    Murabit, Amera; Gnarra, Maria; Mohamed, Adel

    2013-01-01

    The palmaris longus, a slender fusiform muscle, is especially prone to exhibiting anatomical variance relative to other muscles in the upper extremity. The most frequent anatomical variation is the completely absent palmaris longus, followed by the reversed, duplicated, bifid or hypertrophied palmaris longus muscles. The reversed palmaris longus muscle represents a structure that is tendinous proximally and muscular distally (opposite of the normal palmaris longus). The present report describes a case of reversed palmaris longus muscle, followed by a literature review to illustrate the wide spectrum of anatomical variations in the palmaris longus muscle and their clinical and surgical relevance. PMID:24431941

  5. Effects of extreme obliquity variations on the habitability of exoplanets.

    PubMed

    Armstrong, J C; Barnes, R; Domagal-Goldman, S; Breiner, J; Quinn, T R; Meadows, V S

    2014-04-01

    We explore the impact of obliquity variations on planetary habitability in hypothetical systems with high mutual inclination. We show that large-amplitude, high-frequency obliquity oscillations on Earth-like exoplanets can suppress the ice-albedo feedback, increasing the outer edge of the habitable zone. We restricted our exploration to hypothetical systems consisting of a solar-mass star, an Earth-mass planet at 1 AU, and 1 or 2 larger planets. We verified that these systems are stable for 10(8) years with N-body simulations and calculated the obliquity variations induced by the orbital evolution of the Earth-mass planet and a torque from the host star. We ran a simplified energy balance model on the terrestrial planet to assess surface temperature and ice coverage on the planet's surface, and we calculated differences in the outer edge of the habitable zone for planets with rapid obliquity variations. For each hypothetical system, we calculated the outer edge of habitability for two conditions: (1) the full evolution of the planetary spin and orbit and (2) the eccentricity and obliquity fixed at their average values. We recovered previous results that higher values of fixed obliquity and eccentricity expand the habitable zone, but we also found that obliquity oscillations further expand habitable orbits in all cases. Terrestrial planets near the outer edge of the habitable zone may be more likely to support life in systems that induce rapid obliquity oscillations as opposed to fixed-spin planets. Such planets may be the easiest to directly characterize with space-borne telescopes. PMID:24611714

  6. Effects of Extreme Obliquity Variations on the Habitability of Exoplanets

    NASA Technical Reports Server (NTRS)

    Armstrong, J. C.; Barnes, R.; Domagal-Goldman, S.; Breiner, J.; Quinn, T. R.; Meadows, V. S.

    2014-01-01

    We explore the impact of obliquity variations on planetary habitability in hypothetical systems with high mutual inclination. We show that large-amplitude, high-frequency obliquity oscillations on Earth-like exoplanets can suppress the ice-albedo feedback, increasing the outer edge of the habitable zone. We restricted our exploration to hypothetical systems consisting of a solar-mass star, an Earth-mass planet at 1 AU, and 1 or 2 larger planets. We verified that these systems are stable for 108 years with N-body simulations and calculated the obliquity variations induced by the orbital evolution of the Earth-mass planet and a torque from the host star. We ran a simplified energy balance model on the terrestrial planet to assess surface temperature and ice coverage on the planet's surface, and we calculated differences in the outer edge of the habitable zone for planets with rapid obliquity variations. For each hypothetical system, we calculated the outer edge of habitability for two conditions: (1) the full evolution of the planetary spin and orbit and (2) the eccentricity and obliquity fixed at their average values. We recovered previous results that higher values of fixed obliquity and eccentricity expand the habitable zone, but we also found that obliquity oscillations further expand habitable orbits in all cases. Terrestrial planets near the outer edge of the habitable zone may be more likely to support life in systems that induce rapid obliquity oscillations as opposed to fixed-spin planets. Such planets may be the easiest to directly characterize with space-borne telescopes.

  7. Effects of Extreme Obliquity Variations on the Habitability of Exoplanets

    PubMed Central

    Barnes, R.; Domagal-Goldman, S.; Breiner, J.; Quinn, T.R.; Meadows, V.S.

    2014-01-01

    Abstract We explore the impact of obliquity variations on planetary habitability in hypothetical systems with high mutual inclination. We show that large-amplitude, high-frequency obliquity oscillations on Earth-like exoplanets can suppress the ice-albedo feedback, increasing the outer edge of the habitable zone. We restricted our exploration to hypothetical systems consisting of a solar-mass star, an Earth-mass planet at 1 AU, and 1 or 2 larger planets. We verified that these systems are stable for 108 years with N-body simulations and calculated the obliquity variations induced by the orbital evolution of the Earth-mass planet and a torque from the host star. We ran a simplified energy balance model on the terrestrial planet to assess surface temperature and ice coverage on the planet's surface, and we calculated differences in the outer edge of the habitable zone for planets with rapid obliquity variations. For each hypothetical system, we calculated the outer edge of habitability for two conditions: (1) the full evolution of the planetary spin and orbit and (2) the eccentricity and obliquity fixed at their average values. We recovered previous results that higher values of fixed obliquity and eccentricity expand the habitable zone, but we also found that obliquity oscillations further expand habitable orbits in all cases. Terrestrial planets near the outer edge of the habitable zone may be more likely to support life in systems that induce rapid obliquity oscillations as opposed to fixed-spin planets. Such planets may be the easiest to directly characterize with space-borne telescopes. Key Words: Exoplanets—Habitable zone—Energy balance models. Astrobiology 14, 277–291. PMID:24611714

  8. Effects of Microstructure Variations on Macroscopic Terahertz Metafilm Properties

    DOE PAGESBeta

    O'Hara, John F.; Smirnova, Evgenya; Azad, Abul K.; Chen, Hou-Tong; Taylor, Antoinette J.

    2007-01-01

    The properties of planar, single-layer metamaterials, or metafilms, are studied by varying the structural components of the split-ring resonators used to comprise the overall medium. Measurements and simulations reveal how minor design variations in split-ring resonator structures can result in significant changes in the macroscopic properties of the metafilm. A transmission-line/circuit model is also used to clarify some of the behavior and design limitations of the metafilms. Though our results are illustrated in the terahertz frequency range, the work has broader implications, particularly with respect to filtering, modulation, and switching devices.

  9. The Effect of Geographic Units of Analysis on Measuring Geographic Variation in Medical Services Utilization

    PubMed Central

    Park, Jong Heon; Hwang, Kyosang; Lee, Taesik

    2016-01-01

    Objectives: We aimed to evaluate the effect of geographic units of analysis on measuring geographic variation in medical services utilization. For this purpose, we compared geographic variations in the rates of eight major procedures in administrative units (districts) and new areal units organized based on the actual health care use of the population in Korea. Methods: To compare geographic variation in geographic units of analysis, we calculated the age–sex standardized rates of eight major procedures (coronary artery bypass graft surgery, percutaneous transluminal coronary angioplasty, surgery after hip fracture, knee-replacement surgery, caesarean section, hysterectomy, computed tomography scan, and magnetic resonance imaging scan) from the National Health Insurance database in Korea for the 2013 period. Using the coefficient of variation, the extremal quotient, and the systematic component of variation, we measured geographic variation for these eight procedures in districts and new areal units. Results: Compared with districts, new areal units showed a reduction in geographic variation. Extremal quotients and inter-decile ratios for the eight procedures were lower in new areal units. While the coefficient of variation was lower for most procedures in new areal units, the pattern of change of the systematic component of variation between districts and new areal units differed among procedures. Conclusions: Geographic variation in medical service utilization could vary according to the geographic unit of analysis. To determine how geographic characteristics such as population size and number of geographic units affect geographic variation, further studies are needed. PMID:27499165

  10. Anatomical study of total cystoprostatectomy.

    PubMed

    Benoit, G; Boccon-Gibod, L; Steg, A

    1985-01-01

    The authors describe an anatomical study of total cystoprostatectomy. They show that Denonvilliers' fascia is made up of many membranous layers starting at the bladder. They recall the fact that the preprostatic veins are attached at the bottom, not only to the venae dorsales penis, but also to the venae pudendae internae which runs under the levator ani muscle. These preprostatic veins lie inside a vessel-bearing blade of tissue made of muscular and collagenous tissue derived from the anterior vesical wall. This anatomical study recalls the fact that the interprostatorectal dissection line is behind Denonvilliers' fascia and that the preprostatic vein dissection line is on the anterior aspect of the membranous urethra. PMID:4043160

  11. [International anatomical terminology: controversial issues].

    PubMed

    Bolgov, Yu A

    2012-01-01

    The article contains an analysis of problems related to the content of the International anatomical terminology (IAT): the relationship and differences between the terms and concepts as the elements of the professional language of morphologists; forms in which concepts are reflected in IAT; classification of the IAT terms according to the principle of their relationship to the categories of concrete and abstract concepts. PMID:23659048

  12. The anatomical basis of prosopagnosia

    PubMed Central

    Meadows, J. C.

    1974-01-01

    Evidence is presented that patients with prosopagnosia have right anterior inferior occipital lesions in the region of the occipital temporal junction. Many if not all cases have an additional lesion in the left hemisphere; this is often but apparently not always symmetrical with the right hemisphere lesion. This evidence is discussed in relation to the anatomical connections of these regions and the results of experiments in animals. Images PMID:4209556

  13. THE EFFECT OF RANDOM VARIATIONS OF DIFFERENT TYPES ON POPULATION GROWTH

    PubMed Central

    Levins, R.

    1969-01-01

    The probability distributions of population size are derived for populations living in randomly varying environments for both density-dependent and density-independent population growth. The effects of random variation in the rate of increase, the carrying capacity, and sampling variation in numbers are examined. PMID:5256407

  14. Effects of Wolbachia on mitochondrial DNA variation in populations of Athetis lepigone (Lepidoptera: Noctuidae) in China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wolbachia are endosymbiotic bacteria that infect arthropods and incompatibility among strains can affect gene flow within host insect populations, that can result in significant host mitochondrial DNA (MtD) variation. The effects of Wolbachia infection on mtDNA variation was studied in Athetis lepi...

  15. The effect of minority carrier mobility variations on solar cell spectral response

    NASA Technical Reports Server (NTRS)

    Weizer, V. G.; Godlewski, M. P.; Trivisonno, R. J.

    1981-01-01

    Analysis of multistep diffused, high voltage 0.1 ohm-cm solar cells suggests that the increased voltage capability of these cells is correlated with localized variations in the base minority carrier mobility. An attempt to calculate the behavior of those cells revealed unexpected results. It is shown, contrary to what was expected, that spatial variations in the mobility effects severe changes in the short-circuit current and the spectral response. Variations in cell output as a result of imposing abrupt, linear, and exponential mobility variations are presented.

  16. Uncovertebral Anatomic Midline Targeting for Cervical Disc Arthroplasty

    PubMed Central

    Bednar, Drew A.

    2012-01-01

    Study Design Prospective observational cohort. Objective To document the accuracy of uncovertebral anatomic targeting in positioning cervical disc arthroplasty. Summary of Background Data Disc arthroplasty implants depend on midline placement for optimum mechanical function. Fluoroscopy is used to delineate the midline. Anatomic targeting from the uncovertebral joints in the neck may be adequate. We have investigated the efficacy of uncovertebral anatomic targeting for cervical disc arthroplasty. Methods Anatomic uncovertebral midline targeting for disc arthroplasty insertion was performed in 18 male (mean age 51 years, range 27 to 67) and 22 female (mean age 50, range 35 to 70) patients receiving a total of 59 implants over a 5-year period. Device insertion was under only lateral imaging control. Postinsertion operative fluoroscopy with optimized centering was used to record implant position in the anteroposterior plane, and centerline analysis was performed using cursor measurement technology from the GE PACS™ imaging system (GE Medical Systems, Mt. Prospect, IL). Results Analysis found a mean deviation from the ideal midline placement of only 0.7 mm (range, 0 to 2.9 mm). Only three devices were more than 2 mm off the anatomic midline. Conclusion This anatomic technique is effective, safely minimizing imaging resource needs and X-ray exposure to the patient and operating team. PMID:24353946

  17. Turbine vane coolant flow variations and calculated effects on metal temperatures

    NASA Technical Reports Server (NTRS)

    Yeh, F. C.; Meitner, P. L.; Russell, L. M.

    1975-01-01

    Seventy-two air-cooled turbine vanes were tested to determine coolant flow variations among the vanes. Calculations were made to estimate the effect of measured coolant flow variations on local vane metal temperatures. The calculations were based on the following assumed operating conditions: turbine inlet temperature, 1700 K (2600 F); turbine inlet pressure, 31 N/sq cm (45 psia); coolant inlet temperature, 811 K (1000 F); and total coolant to gas flow ratio, 0.065. Variations of total coolant flow were not large (about 10 percent from the arithmetic mean) for all 72 vanes, but variations in local coolant flows were large. The local coolant flow variations ranged from 8 to 75 percent, and calculated metal temperature variations ranged from 8 to 60 K (15 to 180 F).

  18. Effect of gravity wave temperature variations on homogeneous ice nucleation

    NASA Astrophysics Data System (ADS)

    Dinh, Tra; Podglajen, Aurélien; Hertzog, Albert; Legras, Bernard; Plougonven, Riwal

    2015-04-01

    Observations of cirrus clouds in the tropical tropopause layer (TTL) have shown various ice number concentrations (INC) (e.g., Jensen et al. 2013), which has lead to a puzzle regarding their formation. In particular, the frequently observed low numbers of ice crystals seemed hard to reconcile with homogeneous nucleation knowing the ubuquity of gravity waves with vertical velocity of the order of 0.1 m/s. Using artificial time series, Spichtinger and Krämer (2013) have illustrated that the variation of vertical velocity during a nucleation event could terminate it and limit the INC. However, their study was limited to constructed temperature time series. Here, we carry out numerical simulations of homogeneous ice nucleation forced by temperature time series data collected by isopycnic balloon flights near the tropical tropopause. The balloons collected data at high frequency (30 s), so gravity wave signals are well resolved in the temperature time series. With the observed temperature time series, the numerical simulations with homogeneous freezing show a full range of ice number concentrations (INC) as previously observed in the tropical upper troposphere. The simulations confirm that the dynamical time scale of temperature variations (as seen from observations) can be shorter than the nucleation time scale. They show the existence of two regimes for homogeneous ice nucleation : one limited by the depletion of water vapor by the nucleated ice crystals (those we name vapor events) and one limited by the reincrease of temperature after its initial decrease (temperature events). Low INC may thus be obtained for temperature events when the gravity wave perturbations produce a non-persistent cooling rate (even with large magnitude) such that the absolute change in temperature remains small during nucleation. This result for temperature events is explained analytically by a dependence of the INC on the absolute drop in temperature (and not on the cooling rate). This

  19. Epididymal Polar Dissociation: A Previously Undescribed Anatomical Variant

    PubMed Central

    McCain, Stephen; McCain, Scott; Mark, David; Brown, Robin

    2014-01-01

    The normal male external genitalia include the testicles with the epididymis attached posteriorly and the vas deferens arising from this. This case describes an anatomical variation of this normal anatomy not previously reported in the literature. A 17-year-old boy presented with symptoms of intermittent testicular torsion and underwent scrotal exploration. On the left side there was a bell-clapper deformity with the epididymis separated into two parts with the lower pole high in the scrotum and attached to the tunica vaginalis. A normal vas deferens was seen to arise from the isolated lower pole of the epididymis. There was no connection between the vas deferens and the testis or upper pole of epidiymis. This case reminds us of the possibility of anatomical variations and the importance of keeping them in mind to prevent complications at time of surgery. PMID:24883220

  20. Perceptual effects of dialectal and prosodic variation in vowels

    NASA Astrophysics Data System (ADS)

    Fox, Robert Allen; Jacewicz, Ewa; Hatcher, Kristin; Salmons, Joseph

    2005-09-01

    As was reported earlier [Fox et al., J. Acoust. Soc. Am. 114, 2396 (2003)], certain vowels in the Ohio and Wisconsin dialects of American English are shifting in different directions. In addition, we have found that the spectral characteristics of these vowels (e.g., duration and formant frequencies) changed systematically under varying degrees of prosodic prominence, with somewhat different changes occurring within each dialect. The question addressed in the current study is whether naive listeners from these two dialects are sensitive to both the dialect variations and to the prosodically induced spectral differences. Listeners from Ohio and Wisconsin listened to the stimulus tokens [beIt] and [bɛt] produced in each of three prosodic contexts (representing three different levels of prominence). These words were produced by speakers from Ohio or from Wisconsin (none of the listeners were also speakers). Listeners identified the stimulus tokens in terms of vowel quality and indicated whether it was a good, fair, or poor exemplar of that phonetic category. Results showed that both phonetic quality decisions and goodness ratings were systematically and significantly affected by speaker dialect, listener dialect, and prosodic context. Implications of source and nature of ongoing vowel changes in these two dialects will be discussed. [Work partially supported by NIDCD R03 DC005560-01.

  1. The effect of intraspecific variation and heritability on community pattern and robustness.

    PubMed

    Barabás, György; D'Andrea, Rafael

    2016-08-01

    Intraspecific trait variation is widespread in nature, yet its effects on community dynamics are not well understood. Here we explore the consequences of intraspecific trait variation for coexistence in two- and multispecies competitive communities. For two species, the likelihood of coexistence is in general reduced by intraspecific variation, except when the species have almost equal trait means but different trait variances, such that one is a generalist and the other a specialist consumer. In multispecies communities, the only strong effect of non-heritable intraspecific variation is to reduce expected species richness. However, when intraspecific variation is heritable, allowing for the possibility of trait evolution, communities are much more resilient against environmental disturbance and exhibit far more predictable trait patterns. Our results are robust to varying model parameters and relaxing model assumptions. PMID:27335262

  2. Methods for Modeling and Decomposing Treatment Effect Variation in Large-Scale Randomized Trials

    ERIC Educational Resources Information Center

    Ding, Peng; Feller, Avi; Miratrix, Luke

    2015-01-01

    Recent literature has underscored the critical role of treatment effect variation in estimating and understanding causal effects. This approach, however, is in contrast to much of the foundational research on causal inference. Linear models, for example, classically rely on constant treatment effect assumptions, or treatment effects defined by…

  3. Using Seismic Tomography to Estimate the Magnitude of Lateral Variation in effective Mantle Viscosity

    NASA Technical Reports Server (NTRS)

    Sammis, C.; Ivins, E.

    1994-01-01

    Recent tomographic views of mantle are used to estimate corresponding lateral variations in effective viscosity under the assumption that temperature fluctuations about spherically symmetric mean values are the sole source of shear wave velocity anomalies.

  4. Anatomic landmarks for localization of the spinal accessory nerve.

    PubMed

    Durazzo, Marcelo D; Furlan, Julio C; Teixeira, Gilberto V; Friguglietti, Celso U M; Kulcsar, Marco A V; Magalhães, Roberto P; Ferraz, Alberto R; Brandão, Lenine G

    2009-05-01

    This anatomical study examines the anatomic topography and landmarks for localization of the spinal accessory nerve (SAN) during surgical dissections in 40 fresh human cadavers (2 females and 38 males; ages from 22 to 89 years with a mean of 60 years). In the submandibular region, the SAN was found anteriorly to the transverse process of the atlas in 77.5% of the dissections. When the SAN crossed the posterior belly of the digastric muscle, the mean distance from the point of crossing to the tendon of the muscle was 1.75 +/- 0.54 cm. Distally, the SAN crossed between the two heads of the SCM muscle in 45% of the dissections and deep to the muscle in 55%. The SAN exited the posterior border of the sternocleidomastoid muscle in a point superior to the nerve point with a mean distance between these two anatomic parameters of 0.97 +/- 0.46 cm. The mean overall extracranial length of the SAN was 12.02 +/- 2.32 cm, whereas the mean length of the SAN in the posterior triangle was 5.27 +/- 1.52 cm. There were 2-10 lymph nodes in the SAN chain. In conclusion, the nerve point is one of the most reliable anatomic landmarks for localization of the SAN in surgical neck dissections. Although other anatomic parameters including the transverse process of the atlas and the digastric muscle can also be used to localize the SAN, the surgeon should be aware of the possibility of anatomic variations of those parameters. Similar to previous investigations, our results suggest that the number of lymph nodes of the SAN chain greatly varies. PMID:19373901

  5. Effect of light conditions on anatomical and biochemical aspects of somatic and zygotic embryos of hybrid larch (Larix × marschlinsii)

    PubMed Central

    von Aderkas, Patrick; Teyssier, Caroline; Charpentier, Jean-Paul; Gutmann, Markus; Pâques, Luc; Le Metté, Claire; Ader, Kevin; Label, Philippe; Kong, Lisheng; Lelu-Walter, Marie-Anne

    2015-01-01

    Background and Aims In conifers, mature somatic embryos and zygotic embryos appear to resemble one another physiologically and morphologically. However, phenotypes of cloned conifer embryos can be strongly influenced by a number of in vitro factors and in some instances clonal variation can exceed that found in nature. This study examines whether zygotic embryos that develop within light-opaque cones differ from somatic embryos developing in dark/light conditions in vitro. Embryogenesis in larch is well understood both in situ and in vitro and thus provides a suitable system for addressing this question. Methods Features of somatic and zygotic embryos of hybrid larch, Larix × marschlinsii, were quantified, including cotyledon numbers, protein concentration and phenol chemistry. Somatic embryos were placed either in light or darkness for the entire maturation period. Embryos at different developmental stages were embedded and sectioned for histological analysis. Key Results Light, and to a lesser degree abscisic acid (ABA), influenced accumulation of protein and phenolic compounds in somatic and zygotic embryos. Dark-grown mature somatic embryos had more protein (91·77 ± 11·26 µg protein mg–1 f.wt) than either dark-grown zygotic embryos (62·40 ± 5·58) or light-grown somatic embryos (58·15 ± 10·02). Zygotic embryos never accumulated phenolic compounds at any stage, whereas somatic embryos stored phenolic compounds in the embryonal root caps and suspensors. Light induced the production of quercetrin (261·13 ± 9·2 µg g–1 d.wt) in somatic embryos. Mature zygotic embryos that were removed from seeds and placed on medium in light rapidly accumulated phenolics in the embryonal root cap and hypocotyl. Delaying germination with ABA delayed phenolic compound accumulation, restricting it to the embryonal root cap. Conclusions In larch embryos, light has a negative effect on protein accumulation, but a positive effect on phenol

  6. Choroid plexus of the fourth ventricle: Review and anatomic study highlighting anatomical variations.

    PubMed

    Tubbs, R Shane; Shoja, Mohammadali M; Aggarwal, Anjali; Gupta, Tulika; Loukas, Marios; Sahni, Daisy; Ansari, Shaheryar F; Cohen-Gadol, Aaron A

    2016-04-01

    Relatively few studies have been performed that analyze the morphology of the choroid plexus of the fourth ventricle. Due to the importance of this tissue as a landmark on imaging and during surgical intervention of the fourth ventricle, the authors performed a cadaveric study to better characterize this important structure. The choroid plexus of the fourth ventricle of 60 formalin fixed adult human brains was examined and measured. The horizontal distance from the midline to the lateral most point of the protruding tip of the horizontal limbs was measured. In the majority of the 60 brain specimens, right and left horizontal limbs of the choroid plexus were seen extending from the midline and protruding out of their respective lateral apertures of the fourth ventricle and into the subarachnoid space. However, on 3.3% of sides, there was absence of an extension into the foramen of Luschka and in one specimen, this lack of extension into the foramen of Luschka was bilateral. On two sides, there was discontinuity between the midline choroid plexus and the tuft of choroid just outside the foramen of Luschka. For specimens in which the choroid plexus did protrude through the foramen of Luschka (96.7%), these tufts were located anterior to the flocculus and inferolateral to the facial/vestibulocochlear nerve complex and posterosuperior to the glossopharyngeal/vagal/accessory complex. A thorough understanding of the normal and variant anatomy of the fourth ventricular choroid plexus is necessary for those who operate in, or interpret imaging of, this region. PMID:26675624

  7. Color Variations in Screen Text: Effects on Proofreading.

    ERIC Educational Resources Information Center

    Szul, Linda; Berry, Louis

    As the use of computers has become more common in society, human engineering and ergonomics have lagged behind the sciences which developed the equipment. Some research has been done in the past on the effects of screen colors on computer use efficiency, but results were inconclusive. This paper describes a study of the impact of screen color…

  8. Variation in Relevance Judgments and the Measurement of Retrieval Effectiveness.

    ERIC Educational Resources Information Center

    Voorhees, Ellen M.

    2000-01-01

    Discusses the test collections developed in the TREC (Text REtrieval Conference) workshops for information retrieval research and describes a study by NIST (National Institute of Standards and Technology) that verified their reliability by investigating the effect changes in the relevance assessments have on the evaluation of retrieval results.…

  9. Diurnal variation of diazinon volatilization: Soil moisture effects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A field study was conducted to measure the effect of soil moisture on diazinon volatilization under typical semi-arid field conditions. The study comprised three experiments performed with differing soil moisture conditions. Over the course of each three day experiment, diurnal changes in volatiliz...

  10. Sinonasal Anatomical Variants: CT and Endoscopy Study and Its Correlation with Extent of Disease.

    PubMed

    Mendiratta, Vandana; Baisakhiya, Nitish; Singh, Dalbir; Datta, Ginni; Mittal, Amit; Mendiratta, Parveen

    2016-09-01

    To evaluate the incidence of anatomical variations in sinonasal area by nasal endoscopy and CT scan paranasal sinuses and to correlate the anatomical variations in sinonasal area with extent of disease. The present study was conducted on 40 patients of chronic sinusitis. All the patients underwent CT scan paranasal sinus axial and coronal view and nasal endoscopy. The most common anatomical variations were agger nasi cells (80 %), deviated nasal septum (72.5 %) and concha bullosa (47.5 %). Other anatomical variations seen in sinonasal region were uncinate process variations, paradoxical middle turbinate, haller cells, accessory ostia of maxillary sinus, multiseptated sphenoid. Osteomeatal unit (87.5 %) and maxillary sinuses (87.5 %) were the most commonly involved which was followed by anterior ethmoids (70 %), posterior ethmoids (50 %), frontal sinuses (32.5 %) and the sphenoids (20 %). Considering the results obtained, we believe that anatomical variations may increase the risk of sinus mucosal disease. We therefore, emphasize the importance of a careful evaluation of CT study in patients with persistent symptoms of chronic rhinosinusitis. PMID:27508139

  11. Ecological effects of aphid abundance, genotypic variation, and contemporary evolution on plants.

    PubMed

    Turley, Nash E; Johnson, Marc T J

    2015-07-01

    Genetic variation and contemporary evolution within populations can shape the strength and nature of species interactions, but the relative importance of these forces compared to other ecological factors is unclear. We conducted a field experiment testing the effects of genotypic variation, abundance, and presence/absence of green peach aphids (Myzus persicae) on the growth, leaf nitrogen, and carbon of two plant species (Brassica napus and Solanum nigrum). Aphid genotype affected B. napus but not S. nigrum biomass explaining 20 and 7% of the total variation, respectively. Averaging across both plant species, the presence/absence of aphids had a 1.6× larger effect size (Cohen's d) than aphid genotype, and aphid abundance had the strongest negative effects on plant biomass explaining 29% of the total variation. On B. napus, aphid genotypes had different effects on leaf nitrogen depending on their abundance. Aphids did not influence leaf nitrogen in S. nigrum nor leaf carbon in either species. We conducted a second experiment in the field to test whether contemporary evolution could affect plant performance. Aphid populations evolved in as little as five generations, but the rate and direction of this evolution did not consistently vary between plant species. On one host species (B. napus), faster evolving populations had greater negative effects on host plant biomass, with aphid evolutionary rate explaining 23% of the variation in host plant biomass. Together, these results show that genetic variation and evolution in an insect herbivore can play important roles in shaping host plant ecology. PMID:25740334

  12. Recent Earth Oblateness Variations: Unraveling Climate and Postglacial Rebound Effects

    NASA Astrophysics Data System (ADS)

    Dickey, Jean O.; Marcus, Steven L.; de Viron, Olivier; Fukumori, Ichiro

    2002-12-01

    Earth's dynamic oblateness (J2) has been decreasing due to postglacial rebound (PGR). However, J2 began to increase in 1997, indicating a pronounced global-scale mass redistribution within Earth's system. We have determined that the observed increases in J2 are caused primarily by a recent surge in subpolar glacial melting and by mass shifts in the Southern, Pacific, and Indian oceans. When these effects are removed, the residual trend in J2 (-2.9 x 10-11 year-1) becomes consistent with previous estimates of PGR from satellite and eclipse data. The climatic significance of these rapid shifts in glacial and oceanic mass, however, remains to be investigated.

  13. The effect of atmospheric variations on subsurface flow and transport

    SciTech Connect

    Cardle, J.A.; Badran, L.

    1999-09-01

    Yucca Mountain, Nevada, located on the border of the Nevada Test Site in Nye County, is under consideration as a prospective commercial nuclear waste repository for spent nuclear fuel and other high-level radioactive waste. This paper studies the effect that diurnal and seasonal temperature cycles and barometric pressure perturbations have on near-surface flow and transport conditions at Yucca Mountain, both without and with the repository in place. The potential near-surface temperature increase as a direct result of an emplaced repository is also examined.

  14. The effects of goal variation on adult physical activity behaviour.

    PubMed

    Moon, Dal-Hyun; Yun, Joonkoo; McNamee, Jeff

    2016-10-01

    The purposes of this study were to examine the effects of varying levels of goals on increasing daily steps and the frequency of goal achievement among middle-aged adults. Ninety-six adults participated in a randomised control study. Participants were randomly assigned to five different step goal groups: (1) Easy (n = 19), (2) Medium (n = 19), (3) Difficult (n = 19), (4) Do-your-best (n = 19), and (5) No goal (n = 20) based on previous research. The participants wore a pedometer and were asked to reach a pre-established goal during the experimental period. In order to examine the effectiveness of the goal difficulty, (a) an average number of steps taken by different goal conditions and (b) the number of days meeting the assigned goal were tested. A one-way ANCOVA revealed significant step count differences among goal groups. Post hoc analyses indicated that the change in step count in both the Medium and Difficult goal groups was significantly greater than the remaining groups. However, there was no significant difference between the medium and difficult goal conditions. In addition, a one-way ANOVA indicated that there were no significant differences in the frequency of goal achievement among the Easy, Medium, and Difficult goal groups. Results suggest that when promoting physical activity through increasing step counts, researchers and clinicians should design goals that are specific and challenging. PMID:26860430

  15. Variations in the tropical greenhouse effect during El Nino

    SciTech Connect

    Soden, B.J.

    1997-05-01

    Observations of the clear-sky outgoing longwave radiation and sea surface temperature are combined to examine the evolution of the tropical greenhouse effect from colder La Nina conditions in early 1985 to warmer El Nino conditions in late 1987. Although comparison of individual months can suggest a decrease in greenhouse trapping from cold to warm conditions, when the entire 4-yr record is considered a distinct increase in tropical-mean greenhouse trapping of {approximately}2 W m{sup -2} is observed in conjunction with a {approximately}0.4 K increase in tropical-mean sea surface temperature. This observed increase compares favorably with GCM simulations of the change in the clear-sky greenhouse effect during El Nifio-Southern Oscillation (ENSO). Superimposed on top of the SST-driven change in greenhouse trapping are dynamically induced changes in tropical moisture apparently associated with a redistribution of SST during ENSO. The GCM simulations also successfully reproduce this feature, providing reassurance in the ability of GCMs to predict both dynamically and thermodynamically driven changes in greenhouse trapping. 25 refs., 3 figs., 1 tab.

  16. Brain anatomical network and intelligence.

    PubMed

    Li, Yonghui; Liu, Yong; Li, Jun; Qin, Wen; Li, Kuncheng; Yu, Chunshui; Jiang, Tianzi

    2009-05-01

    Intuitively, higher intelligence might be assumed to correspond to more efficient information transfer in the brain, but no direct evidence has been reported from the perspective of brain networks. In this study, we performed extensive analyses to test the hypothesis that individual differences in intelligence are associated with brain structural organization, and in particular that higher scores on intelligence tests are related to greater global efficiency of the brain anatomical network. We constructed binary and weighted brain anatomical networks in each of 79 healthy young adults utilizing diffusion tensor tractography and calculated topological properties of the networks using a graph theoretical method. Based on their IQ test scores, all subjects were divided into general and high intelligence groups and significantly higher global efficiencies were found in the networks of the latter group. Moreover, we showed significant correlations between IQ scores and network properties across all subjects while controlling for age and gender. Specifically, higher intelligence scores corresponded to a shorter characteristic path length and a higher global efficiency of the networks, indicating a more efficient parallel information transfer in the brain. The results were consistently observed not only in the binary but also in the weighted networks, which together provide convergent evidence for our hypothesis. Our findings suggest that the efficiency of brain structural organization may be an important biological basis for intelligence. PMID:19492086

  17. Anatomical heterogeneity of Alzheimer disease

    PubMed Central

    Noh, Young; Jeon, Seun; Seo, Sang Won; Kim, Geon Ha; Cho, Hanna; Ye, Byoung Seok; Yoon, Cindy W.; Kim, Hee Jin; Chin, Juhee; Park, Kee Hyung; Heilman, Kenneth M.

    2014-01-01

    Objective: Because the signs associated with dementia due to Alzheimer disease (AD) can be heterogeneous, the goal of this study was to use 3-dimensional MRI to examine the various patterns of cortical atrophy that can be associated with dementia of AD type, and to investigate whether AD dementia can be categorized into anatomical subtypes. Methods: High-resolution T1-weighted volumetric MRIs were taken of 152 patients in their earlier stages of AD dementia. The images were processed to measure cortical thickness, and hierarchical agglomerative cluster analysis was performed using Ward's clustering linkage. The identified clusters of patients were compared with an age- and sex-matched control group using a general linear model. Results: There were several distinct patterns of cortical atrophy and the number of patterns varied according to the level of cluster analyses. At the 3-cluster level, patients were divided into (1) bilateral medial temporal–dominant atrophy subtype (n = 52, ∼34.2%), (2) parietal-dominant subtype (n = 28, ∼18.4%) in which the bilateral parietal lobes, the precuneus, along with bilateral dorsolateral frontal lobes, were atrophic, and (3) diffuse atrophy subtype (n = 72, ∼47.4%) in which nearly all association cortices revealed atrophy. These 3 subtypes also differed in their demographic and clinical features. Conclusions: This cluster analysis of cortical thickness of the entire brain showed that AD dementia in the earlier stages can be categorized into various anatomical subtypes, with distinct clinical features. PMID:25344382

  18. Brain Anatomical Network and Intelligence

    PubMed Central

    Li, Jun; Qin, Wen; Li, Kuncheng; Yu, Chunshui; Jiang, Tianzi

    2009-01-01

    Intuitively, higher intelligence might be assumed to correspond to more efficient information transfer in the brain, but no direct evidence has been reported from the perspective of brain networks. In this study, we performed extensive analyses to test the hypothesis that individual differences in intelligence are associated with brain structural organization, and in particular that higher scores on intelligence tests are related to greater global efficiency of the brain anatomical network. We constructed binary and weighted brain anatomical networks in each of 79 healthy young adults utilizing diffusion tensor tractography and calculated topological properties of the networks using a graph theoretical method. Based on their IQ test scores, all subjects were divided into general and high intelligence groups and significantly higher global efficiencies were found in the networks of the latter group. Moreover, we showed significant correlations between IQ scores and network properties across all subjects while controlling for age and gender. Specifically, higher intelligence scores corresponded to a shorter characteristic path length and a higher global efficiency of the networks, indicating a more efficient parallel information transfer in the brain. The results were consistently observed not only in the binary but also in the weighted networks, which together provide convergent evidence for our hypothesis. Our findings suggest that the efficiency of brain structural organization may be an important biological basis for intelligence. PMID:19492086

  19. Digital imaging in anatomic pathology.

    PubMed

    O'Brien, M J; Sotnikov, A V

    1996-10-01

    Advances in computer technology continue to bring new innovations to departments of anatomic pathology. This article briefly reviews the present status of digital optical imaging, and explores the directions that this technology may lead over the next several years. Technical requirements for digital microscopic and gross imaging, and the available options for image archival and retrieval are summarized. The advantages of digital images over conventional photography in the conference room, and the usefulness of digital imaging in the frozen section suite and gross room, as an adjunct to surgical signout and as a resource for training and education, are discussed. An approach to the future construction of digital histologic sections and the computer as microscope is described. The digital technologic applications that are now available as components of the surgical pathologist's workstation are enumerated. These include laboratory information systems, computerized voice recognition, and on-line or CD-based literature searching, texts and atlases and, in some departments, on-line image databases. The authors suggest that, in addition to these resources that are already available, tomorrow's surgical pathology workstation will include network-linked digital histologic databases, on-line software for image analysis and 3-D image enhancement, expert systems, and ultimately, advanced pattern recognition capabilities. In conclusion, the authors submit that digital optical imaging is likely to have a significant and positive impact on the future development of anatomic pathology. PMID:8853053

  20. Quantifying the Variation in the Effective Population Size Within a Genome

    PubMed Central

    Gossmann, Toni I.; Woolfit, Megan; Eyre-Walker, Adam

    2011-01-01

    The effective population size (Ne) is one of the most fundamental parameters in population genetics. It is thought to vary across the genome as a consequence of differences in the rate of recombination and the density of selected sites due to the processes of genetic hitchhiking and background selection. Although it is known that there is intragenomic variation in the effective population size in some species, it is not known whether this is widespread or how much variation in the effective population size there is. Here, we test whether the effective population size varies across the genome, between protein-coding genes, in 10 eukaryotic species by considering whether there is significant variation in neutral diversity, taking into account differences in the mutation rate between loci by using the divergence between species. In most species we find significant evidence of variation. We investigate whether the variation in Ne is correlated to recombination rate and the density of selected sites in four species, for which these data are available. We find that Ne is positively correlated to recombination rate in one species, Drosophila melanogaster, and negatively correlated to a measure of the density of selected sites in two others, humans and Arabidopsis thaliana. However, much of the variation remains unexplained. We use a hierarchical Bayesian analysis to quantify the amount of variation in the effective population size and show that it is quite modest in all species—most genes have an Ne that is within a few fold of all other genes. Nonetheless we show that this modest variation in Ne is sufficient to cause significant differences in the efficiency of natural selection across the genome, by demonstrating that the ratio of the number of nonsynonymous to synonymous polymorphisms is significantly correlated to synonymous diversity and estimates of Ne, even taking into account the obvious nonindependence between these measures. PMID:21954163

  1. Recent Earth oblateness variations: unraveling climate and postglacial rebound effects.

    PubMed

    Dickey, Jean O; Marcus, Steven L; de Viron, Olivier; Fukumori, Ichiro

    2002-12-01

    Earth's dynamic oblateness (J2) has been decreasing due to postglacial rebound (PGR). However, J2 began to increase in 1997, indicating a pronounced global-scale mass redistribution within Earth's system. We have determined that the observed increases in J2 are caused primarily by a recent surge in subpolar glacial melting and by mass shifts in the Southern, Pacific, and Indian oceans. When these effects are removed, the residual trend in J2 (-2.9 x 10(-11) year-1) becomes consistent with previous estimates of PGR from satellite and eclipse data. The climatic significance of these rapid shifts in glacial and oceanic mass, however, remains to be investigated. PMID:12471253

  2. Design of experiments based variation mode and effect analysis of a conceptual air launched SLV

    NASA Astrophysics Data System (ADS)

    Rafique, Amer Farhan; Zeeshan, Qasim; Kamran, Ali

    2014-12-01

    Conceptual design stage is where the knowledge about the variation in system is still quite vague and herein we intend to analyze and compare various probable design concepts for Air Launched SLV by the use of basic variation mode and effect analysis. In this paper we present a methodology for the Variation Mode and Effect Analysis using Latin Hypercube Sampling based Design of Experiments for the conceptual Air launched Satellite Launch Vehicle. Variations are induced in the Control Variables based on knowledge and experience. The methodology is used to quantify the effect of Noise Factors on the performance of a conceptual Air Launched SLV. The insertion altitude of the Air Launched SLV is the Key Performance Indicator. Preliminary results of the performance and analysis for the simulated experiments are presented here. The performance of the proposed procedure has been tested and, thus, validated by the Air Launched SLV design problem. The Design of Experiment based Variation mode and effect analysis approach is intended for initial conceptual design purposes, thus, providing an immediate insight to the performance of the system in general and quantification of the sensitivity of the key performance indicator in particular, subject to the variations in noise factors prior to the detailed design phase.

  3. Effects of lateral viscosity variations on long-wavelength geoid anomalies and topography

    NASA Technical Reports Server (NTRS)

    Richards, Mark A.; Hager, Bradford H.

    1989-01-01

    The effects of lateral variations in the earth mantle viscosity, due to temperature- or stress-dependent rheology, on the long-wavelength geoid anomalies are examined. Results from simple perturbation theory combined with findings from numerical models for convective flow led to a conclusion that the geoid due to the very longest wavelength convective patterns (l = 2,3) on earth is probably not seriously contaminated by lateral variations due either to temperature or stress dependence. Considerable contamination of the higher-degree geoid (l value of no less than 4) is to be expected due to lateral viscosity variations in phase with the fundamental convection scale length.

  4. Effect of Root-Zone Moisture Variations on Growth of Lettuce and Pea Plants

    NASA Astrophysics Data System (ADS)

    Ilieva, Iliana; Ivanova, Tania

    2008-06-01

    Variations in substrate moisture lead to changes in water and oxygen availability to plant roots. Ground experiments were carried out in the laboratory prototype of SVET-2 Space Greenhouse to study the effect of variation of root-zone moisture conditions on growth of lettuce and pea plants. The effect of transient increase (for 1 day) and drastic increase (waterlogging for 10 days) of substrate moisture was studied with 16-day old pea and 21-day old lettuce plants respectively. Pea height and fresh biomass accumulation were not affected by transient substrate moisture increase. Net photosynthetic rate (Pn) of pea plants showed fast response to substrate moisture variation, while chlorophyll content did not change. Drastic change of substrate moisture suppressed lettuce Pn, chlorophyll biosynthesis and plant growth. These parameters slowly recovered after termination of waterlogging treatment but lettuce yield was greatly affected. The results showed that the most sensitive physiological parameter to substrate moisture variations is photosynthesis.

  5. Automatically Generated, Anatomically Accurate Meshes for Cardiac Electrophysiology Problems

    PubMed Central

    Prassl, Anton J.; Kickinger, Ferdinand; Ahammer, Helmut; Grau, Vicente; Schneider, Jürgen E.; Hofer, Ernst; Vigmond, Edward J.; Trayanova, Natalia A.

    2010-01-01

    Significant advancements in imaging technology and the dramatic increase in computer power over the last few years broke the ground for the construction of anatomically realistic models of the heart at an unprecedented level of detail. To effectively make use of high-resolution imaging datasets for modeling purposes, the imaged objects have to be discretized. This procedure is trivial for structured grids. However, to develop generally applicable heart models, unstructured grids are much preferable. In this study, a novel image-based unstructured mesh generation technique is proposed. It uses the dual mesh of an octree applied directly to segmented 3-D image stacks. The method produces conformal, boundary-fitted, and hexahedra-dominant meshes. The algorithm operates fully automatically with no requirements for interactivity and generates accurate volume-preserving representations of arbitrarily complex geometries with smooth surfaces. The method is very well suited for cardiac electrophysiological simulations. In the myocardium, the algorithm minimizes variations in element size, whereas in the surrounding medium, the element size is grown larger with the distance to the myocardial surfaces to reduce the computational burden. The numerical feasibility of the approach is demonstrated by discretizing and solving the monodomain and bidomain equations on the generated grids for two preparations of high experimental relevance, a left ventricular wedge preparation, and a papillary muscle. PMID:19203877

  6. Variations in impact effects among IIIE iron meteorites

    NASA Astrophysics Data System (ADS)

    Breen, John P.; Rubin, Alan E.; Wasson, John T.

    2016-09-01

    Group-IIIE iron meteorites can be ordered into four categories reflecting increasing degrees of shock alteration. Weakly shocked samples (Armanty, Colonia Obrera, Coopertown, Porto Alegre, Rhine Villa, Staunton, and Tanokami Mountain) have haxonite within plessite, unrecrystallized kamacite grains containing Neumann lines or possessing the ɛ structure, and sulfide inclusions typically consisting of polycrystalline troilite with daubréelite exsolution lamellae. The only moderately shocked sample is NWA 4704, in which haxonite has been partially decomposed to graphite; the majority of the kamacite in NWA 4704 is recrystallized, and its sulfide inclusions were partly melted. Strongly shocked samples (Cachiyuyal, Kokstad, and Paloduro) contain graphite and no haxonite, suggesting that pre-existing haxonite fully decomposed. Also present in these rocks are recrystallized kamacite and melted troilite. Residual heat from the impact caused annealing and recrystallization of kamacite as well as the decomposition of haxonite into graphite. Severely shocked samples (Aliskerovo and Willow Creek) have sulfide-rich assemblages consisting of fragmental and subhedral daubréelite crystals, 1-4 vol% spidery troilite filaments, and 30-50 vol% low-Ni kamacite grains, some of which contain up to 6.0 wt% Co; haxonite in these inclusions has fully decomposed to graphite. The wide range of impact effects in IIIE irons is attributed to one or more major collision(s) on the parent asteroid that affected different group members to different extents depending on their proximity to the impact point.

  7. Variations in impact effects among IIIE iron meteorites

    NASA Astrophysics Data System (ADS)

    Breen, John P.; Rubin, Alan E.; Wasson, John T.

    2016-07-01

    Group-IIIE iron meteorites can be ordered into four categories reflecting increasing degrees of shock alteration. Weakly shocked samples (Armanty, Colonia Obrera, Coopertown, Porto Alegre, Rhine Villa, Staunton, and Tanokami Mountain) have haxonite within plessite, unrecrystallized kamacite grains containing Neumann lines or possessing the ɛ structure, and sulfide inclusions typically consisting of polycrystalline troilite with daubréelite exsolution lamellae. The only moderately shocked sample is NWA 4704, in which haxonite has been partially decomposed to graphite; the majority of the kamacite in NWA 4704 is recrystallized, and its sulfide inclusions were partly melted. Strongly shocked samples (Cachiyuyal, Kokstad, and Paloduro) contain graphite and no haxonite, suggesting that pre-existing haxonite fully decomposed. Also present in these rocks are recrystallized kamacite and melted troilite. Residual heat from the impact caused annealing and recrystallization of kamacite as well as the decomposition of haxonite into graphite. Severely shocked samples (Aliskerovo and Willow Creek) have sulfide-rich assemblages consisting of fragmental and subhedral daubréelite crystals, 1-4 vol% spidery troilite filaments, and 30-50 vol% low-Ni kamacite grains, some of which contain up to 6.0 wt% Co; haxonite in these inclusions has fully decomposed to graphite. The wide range of impact effects in IIIE irons is attributed to one or more major collision(s) on the parent asteroid that affected different group members to different extents depending on their proximity to the impact point.

  8. Regulatory effects of matrix protein variations on influenza virus growth.

    PubMed

    Yasuda, J; Toyoda, T; Nakayama, M; Ishihama, A

    1993-01-01

    Influenza virus A/WSN/33 forms large plaques (> 3 mm diameter) on MDCK cells whereas A/Aichi/2/68 forms only small plaques (< 1 mm diameter). Fast growing reassortants (AWM), isolated by mixed infection of MDCK cells with these two virus strains in the presence of anti-WSN antibodies, all carried the M gene from WSN. On MDCK cells, these reassortants produced progeny viruses as rapidly as did WSN, and the virus yield was as high as Aichi. The fast-growing reassortants overcame the growth inhibitory effect of lignins. Pulse-labeling experiments at various times after virus infection showed that the reassortant AWM started to synthesize viral proteins earlier than Aichi. Taken together, we conclude that upon infecting MDCK cells, the reassortant viruses advance rapidly into the growth cycle, thereby leading to an elevated level of progeny viruses in the early period of infection. Possible mechanisms of the M gene involvement in the determination of virus growth rate are discussed, in connection with multiple functions of the M proteins. PMID:8257290

  9. Vascular rings: a radiological review of anatomical variations

    PubMed Central

    Ganie, Iqbal Siddi; Amod, Khatija; Reddy, Darshan

    2016-01-01

    Summary Background The imaging modalities used to diagnose vascular rings have evolved over time, from basic radiographic studies to advanced cross-sectional imaging. The goal of preoperative imaging is to provide the surgeon with an accurate representation of the ring configuration so that the surgical approach may be planned. Methods We conducted a review of all patients with vascular rings who underwent surgery at Inkosi Albert Luthuli Central Hospital, Durban, South Africa from 1 July 2008 to 1 July 2013. Results Eight patients were diagnosed with vascular rings. Seven patients had an abnormal plain chest radiograph (right aortic arch, tracheal narrowing, or abnormal mediastinal silhouette), while in six patients the contrast oesophagogram demonstrated a fixed extrinsic oesophageal indentation. Computed tomography angiography confirmed the pathology in all cases, with six double aortic arches and two right aortic arches with aberrant left subclavian artery and left ligamentum arteriosum. Conclusions We advocate a diagnostic imaging algorithm consisting of plain chest radiography, contrast oesophagogram and computed tomography angiography prior to surgery. Magnetic resonance imaging may provide an alternative axial imaging modality depending on institutional preference. PMID:26523459

  10. Straight, semi-anatomic and anatomic TMJ implants: the influence of condylar geometry and bone fixation screws.

    PubMed

    Ramos, A; Completo, A; Relvas, C; Mesnard, M; Simões, J A

    2011-07-01

    A 3D finite element model of in vitro intact and implanted mandibles with different temporomandibular joints (TMJ) was analyzed. Three TMJ implant geometries were assessed. The displacements, stress and strain fields on the condyle were obtained for both simulated cases. Strains were also assessed near the screws that fixate the implant to the mandible. The geometry of the mandible was obtained through 3D digitalization of a synthetic model. The TMJ implants studied were modelled considering a commercial implant which was also used to create semi-anatomic and anatomic implants that were analyzed and to assess the influence of the geometry. Numerical finite element models were built and the implants were positioned by an experienced orofacial surgeon. All implants were fixed by four screws which were placed in the same position on the mandible. The boundary conditions were simulated considering the support on the incisive tooth, the loads of the five most important muscular forces and a 5mm mouth aperture. This study indicates that the deformation on the intact mandible was similar when an anatomic implant was considered in the implanted mandible. However, the anatomic geometry presented some problems concerning the implant integrity due to geometric variations. The geometry of TMJ implant also played a role relatively to the screws structural integration and bone fixation. The geometry of TMJ implant defines the necessary number of screws and position in the mandible fixation. PMID:20801667

  11. Preliminary Study on Appearance-Based Detection of Anatomical Point Landmarks in Body Trunk CT Images

    NASA Astrophysics Data System (ADS)

    Nemoto, Mitsutaka; Nomura, Yukihiro; Hanaoka, Shohei; Masutani, Yoshitaka; Yoshikawa, Takeharu; Hayashi, Naoto; Yoshioka, Naoki; Ohtomo, Kuni

    Anatomical point landmarks as most primitive anatomical knowledge are useful for medical image understanding. In this study, we propose a detection method for anatomical point landmark based on appearance models, which include gray-level statistical variations at point landmarks and their surrounding area. The models are built based on results of Principal Component Analysis (PCA) of sample data sets. In addition, we employed generative learning method by transforming ROI of sample data. In this study, we evaluated our method with 24 data sets of body trunk CT images and obtained 95.8 ± 7.3 % of the average sensitivity in 28 landmarks.

  12. Estimating Genetic and Maternal Effects Determining Variation in Immune Function of a Mixed-Mating Snail

    PubMed Central

    Seppälä, Otto; Langeloh, Laura

    2016-01-01

    Evolution of host defenses such as immune function requires heritable genetic variation in them. However, also non-genetic maternal effects can contribute to phenotypic variation, thus being an alternative target for natural selection. We investigated the role of individuals’ genetic background and maternal effects in determining immune defense traits (phenoloxidase and antibacterial activity of hemolymph), as well as in survival and growth, in the simultaneously hermaphroditic snail Lymnaea stagnalis. We utilized the mixed mating system of this species by producing full-sib families in which each parental snail had produced offspring as both a dam and as a sire, and tested whether genetic background (family) and non-genetic maternal effects (dam nested within family) explain trait variation. Immune defense traits and growth were affected solely by individuals’ genetic background. Survival of snails did not show family-level variation. Additionally, some snails were produced through self-fertilization. They showed reduced growth and survival suggesting recessive load or overdominance. Immune defense traits did not respond to inbreeding. Our results suggest that the variation in snail immune function and growth was due to genetic differences. Since immune traits did not respond to inbreeding, this variation is most likely due to additive or epistatic genetic variance. PMID:27551822

  13. Estimating Genetic and Maternal Effects Determining Variation in Immune Function of a Mixed-Mating Snail.

    PubMed

    Seppälä, Otto; Langeloh, Laura

    2016-01-01

    Evolution of host defenses such as immune function requires heritable genetic variation in them. However, also non-genetic maternal effects can contribute to phenotypic variation, thus being an alternative target for natural selection. We investigated the role of individuals' genetic background and maternal effects in determining immune defense traits (phenoloxidase and antibacterial activity of hemolymph), as well as in survival and growth, in the simultaneously hermaphroditic snail Lymnaea stagnalis. We utilized the mixed mating system of this species by producing full-sib families in which each parental snail had produced offspring as both a dam and as a sire, and tested whether genetic background (family) and non-genetic maternal effects (dam nested within family) explain trait variation. Immune defense traits and growth were affected solely by individuals' genetic background. Survival of snails did not show family-level variation. Additionally, some snails were produced through self-fertilization. They showed reduced growth and survival suggesting recessive load or overdominance. Immune defense traits did not respond to inbreeding. Our results suggest that the variation in snail immune function and growth was due to genetic differences. Since immune traits did not respond to inbreeding, this variation is most likely due to additive or epistatic genetic variance. PMID:27551822

  14. Effects of Fertile Mantle Compositional Variation and Spreading Rate Variation on the Working of Global Ocean Ridges

    NASA Astrophysics Data System (ADS)

    Niu, Y.; O'Hara, M. J.

    2014-12-01

    Mantle temperature variation, plate spreading rate variation and mantle compositional variation have been considered to be the three fundamental variables that govern the working of global ocean ridges [1]. An analysis demonstrates that mantle compositional variation exerts the primary control on ocean ridge processes; it determines (1) variation in both composition and mode of mantle mineralogy, (2) variation of mantle density, (3) variation of ridge axial depth, (4) source-inherited MORB compositional variation, (4) density-controlled variation in the amplitude of mantle upwelling, (5) apparent variation in the extent of melting, and (6) the correlated variation of MORB chemistry with ridge axial depth [2]. The above interpretations are reinforced by the updated MORB database [3]. The new database also confirms spreading rate control on the extent of melting as shown previously [4]. Mantle temperature variation could play a part, but its overstated role [3,5] results from a basic error (1) in treating ridge axial depth variation as evidence of mantle temperature variation by ignoring the intrinsic control of mantle composition, (2) in treating "mantle plume" influenced ridges (e.g., Iceland) as normal ridges of plate spreading origin, and (3) in treating low Vs at greater depths (> 300 km vs. < 200 km beneath ridges) beneath these "mantle plume" influenced ridges as evidence for hot ridge mantle. In order to understand the working of global ocean ridges, we must avoid plume-influenced ridges (e.g., in the vicinity of Iceland) and remove/average out data from such ridges. As a result, the correlations (e.g., between ridge axial depth, mantle low Vs anomaly, and some geochemical parameters) required for the interpretation of mantle temperature control all disappear. There is thus no evidence for large mantle temperature variation away from ridges influenced by "mantle plumes". References: [1] Niu et al., 2001, Earth Planet Sci. Lett., 186, 383-399; [2] Niu & O

  15. Statistical approach to anatomical landmark extraction in AP radiographs

    NASA Astrophysics Data System (ADS)

    Bernard, Rok; Pernus, Franjo

    2001-07-01

    A novel method for the automated extraction of important geometrical parameters of the pelvis and hips from APR images is presented. The shape and intensity variations in APR images are encompassed by the statistical shape and appearance models built from a set of training images for each of the three anatomies, i.e., pelvis, right and left hip, separately. The identification of the pelvis and hips is defined as a flexible object recognition problem, which is solved by generating anatomically plausible object instances and matching them to the APR image. The criterion function minimizes the resulting match error and considers the object topology. The obtained flexible object defines the positions of anatomical landmarks, which are further used to calculate the hip joint contact stress. A leave-one-out test was used to evaluate the performance of the proposed method on a set of 26 APR images. The results show the method is able to properly treat image variations and can reliably and accurately identify anatomies in the image and extract the anatomical landmarks needed in the hip joint contact stress calculation.

  16. Anatomic consideration for preventive implantation.

    PubMed

    Denissen, H W; Kalk, W; Veldhuis, H A; van Waas, M A

    1993-01-01

    The aim of preventive implant therapy is to prevent or delay loss of alveolar ridge bone mass. For use in an anatomic study of 60 mandibles, resorption of the alveolar ridge was classified into four preventive stages: (1) after extraction of teeth; (2) after initial resorption; (3) when the ridge has atrophied to a knife-edge shape; and (4) when only basal bone remains. Implantation in stage 3 necessitates removal of the knife-edge ridge to create space for cylindrical implants. Therefore, implantation in stage 2 is advocated to prevent the development of stage 3. The aim of implantation in stage 4 is to prevent total loss of function of the atrophic mandible. PMID:8359876

  17. Digital photography in anatomical pathology.

    PubMed

    Leong, F J; Leong, A S

    2004-01-01

    Digital imaging has made major inroads into the routine practice of anatomical pathology and replaces photographic prints and Kodachromes for reporting and conference purposes. More advanced systems coupled to computers allow greater versatility and speed of turnaround as well as lower costs of incorporating macroscopic and microscopic pictures into pathology reports and publications. Digital images allow transmission to remote sites via the Internet for consultation, quality assurance and educational purposes, and can be stored on and disseminated by CD-ROM. Total slide digitisation is now a reality and will replace glass slides to a large extent. Three-dimensional images of gross specimens can be assembled and posted on websites for interactive educational programmes. There are also applications in research, allowing more objective and automated quantitation of a variety of morphological and immunohistological parameters. Early reports indicate that medical vision systems are a reality and can provide for automated computer-generated histopathological diagnosis and quality assurance. PMID:15048004

  18. Relative Contribution of Animal and Muscle Effects to Variation in Beef Lean Color Stability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our objective was to determine the extent to which animal effects influence variation in beef lean color stability in comparison to muscle and quality grade effects. Carcasses (n = 100) equally representing the US Choice and Select grades were selected on five days from a commercial beef processing...

  19. Effects of Geometric Variations on Lift Augmentation of Simple-plenum-chamber Ground-effect Models

    NASA Technical Reports Server (NTRS)

    Davenport, Edwin E.

    1961-01-01

    Considerable interest has been shown during recent years in ground-effect vehicles. Of the various types proposed, the simple-plenum-chamber vehicle has indicated promise because, although the lift augmentation obtainable appears to be less than that of an annular jet, it may be somewhat less complicated structurally. The present investigation was undertaken to study the effects of some geometric variations upon lift augmentation of a simple plenum chamber within ground proximity. The variables included the ratio inlet area to exit area, plenum-chamber depth, and entrance configuration. An optimum plenum-chamber depth appeared to be between 3 and 10 percent of the plenum-chamber diameter with a ratio of inlet diameter to plenum-chamber diameter of 0.15 for the range of plenum-chamber depths investigated. The most important effect of multiple inlets was the elimination of negative lift augmentation, which was experienced with single sharp-edged inlets, at intermediate heights. Installation of a flared inlet and a turning-vane assembly improved lift augmentation of a single-inlet configuration at intermediate heights.

  20. PET Image Reconstruction Using Information Theoretic Anatomical Priors

    PubMed Central

    Somayajula, Sangeetha; Panagiotou, Christos; Rangarajan, Anand; Li, Quanzheng; Arridge, Simon R.

    2011-01-01

    We describe a nonparametric framework for incorporating information from co-registered anatomical images into positron emission tomographic (PET) image reconstruction through priors based on information theoretic similarity measures. We compare and evaluate the use of mutual information (MI) and joint entropy (JE) between feature vectors extracted from the anatomical and PET images as priors in PET reconstruction. Scale-space theory provides a framework for the analysis of images at different levels of detail, and we use this approach to define feature vectors that emphasize prominent boundaries in the anatomical and functional images, and attach less importance to detail and noise that is less likely to be correlated in the two images. Through simulations that model the best case scenario of perfect agreement between the anatomical and functional images, and a more realistic situation with a real magnetic resonance image and a PET phantom that has partial volumes and a smooth variation of intensities, we evaluate the performance of MI and JE based priors in comparison to a Gaussian quadratic prior, which does not use any anatomical information. We also apply this method to clinical brain scan data using F18 Fallypride, a tracer that binds to dopamine receptors and therefore localizes mainly in the striatum. We present an efficient method of computing these priors and their derivatives based on fast Fourier transforms that reduce the complexity of their convolution-like expressions. Our results indicate that while sensitive to initialization and choice of hyperparameters, information theoretic priors can reconstruct images with higher contrast and superior quantitation than quadratic priors. PMID:20851790

  1. HERITABILITY OF AND EARLY ENVIRONMENT EFFECTS ON VARIATION IN MATING PREFERENCES

    PubMed Central

    Schielzeth, Holger; Bolund, Elisabeth; Forstmeier, Wolfgang

    2010-01-01

    Many species show substantial between-individual variation in mating preferences, but studying the causes of such variation remains a challenge. For example, the relative importance of heritable variation versus shared early environment effects (like sexual imprinting) on mating preferences has never been quantified in a population of animals. Here, we estimate the heritability of and early rearing effects on mate choice decisions in zebra finches based on the similarity of choices between pairs of genetic sisters raised apart and pairs of unrelated foster sisters. We found a low and nonsignificant heritability of preferences and no significant shared early rearing effects. A literature review shows that a low heritability of preferences is rather typical, whereas empirical tests for the relevance of sexual imprinting within populations are currently limited to very few studies. Although effects on preference functions (i.e., which male to prefer) were weak, we found strong individual consistency in choice behavior and part of this variation was heritable. It seems likely that variation in choice behavior (choosiness, responsiveness, sampling behavior) would produce patterns of nonrandom mating and this might be the more important source of between-individual differences in mating patterns. PMID:19895552

  2. Variation in wood fibre traits among eight populations of Dipterocarpus indicus in Western Ghats, India.

    PubMed

    Prasad, A G Devi; Al-Sagheer, Nageeb A

    2012-03-01

    Wood elements and anatomical ratio of Dipterocarpus indicus were studied to evaluate variation among populations and to recommend for end selection. The variation of wood element [fibre length (FL), fibre diameter (FD), lumen diameter (LD), cell wall thickness (CWT), double wall thickness (DWT), and lumen volume (LV)] and anatomical ratio [fibre lumen area (FLA), slenderness ratio (SR) and runkel ratio (RR)] were investigated in a girth class of 100 - 120 cm among eight populations of Dipterocarpus indicus in Western Ghats, India. The study revealed a significant variations in FL (0.2426), FD (4.7019), LD (3.1689), CWT (2.7104), DWT and (5.4298) among populations. The variations in anatomical ratios were significant among populations except in case of LV. The causes of variations among populations in their wood traits were attributed to the site factors. The interaction between genetic makeup of wood traits combined with effects of edaphic, local and regional climatic conditions reflect the amount of variation among populations. The highest coefficient of variation (CV %) for FL, FD, CWT and DWT was recorded in population of Gundya whereas low coefficient of variation were recorded in the population of Makuta (FL), Devimane (FD, CWT and DWT), and Sampaje (LD). The wood of Dipterocarpus indicus was found undesirable for pulp wood but can be utilized for plywood timbers. PMID:23033683

  3. Segmentation of medical images using explicit anatomical knowledge

    NASA Astrophysics Data System (ADS)

    Wilson, Laurie S.; Brown, Stephen; Brown, Matthew S.; Young, Jeanne; Li, Rongxin; Luo, Suhuai; Brandt, Lee

    1999-07-01

    Knowledge-based image segmentation is defined in terms of the separation of image analysis procedures and representation of knowledge. Such architecture is particularly suitable for medical image segmentation, because of the large amount of structured domain knowledge. A general methodology for the application of knowledge-based methods to medical image segmentation is described. This includes frames for knowledge representation, fuzzy logic for anatomical variations, and a strategy for determining the order of segmentation from the modal specification. This method has been applied to three separate problems, 3D thoracic CT, chest X-rays and CT angiography. The application of the same methodology to such a range of applications suggests a major role in medical imaging for segmentation methods incorporating representation of anatomical knowledge.

  4. Ontogenetic variation in cold tolerance plasticity in Drosophila: is the Bogert effect bogus?

    NASA Astrophysics Data System (ADS)

    Mitchell, Katherine A.; Sinclair, Brent J.; Terblanche, John S.

    2013-03-01

    Ontogenetic variation in plasticity is important to understanding mechanisms and patterns of thermal tolerance variation. The Bogert effect postulates that, to compensate for their inability to behaviourally thermoregulate, less-mobile life stages of ectotherms are expected to show greater plasticity of thermal tolerance than more-mobile life stages. We test this general prediction by comparing plasticity of thermal tolerance (rapid cold-hardening, RCH) between mobile adults and less-mobile larvae of 16 Drosophila species. We find an RCH response in adults of 13 species but only in larvae of four species. Thus, the Bogert effect is not as widespread as expected.

  5. An Anatomically Validated Brachial Plexus Contouring Method for Intensity Modulated Radiation Therapy Planning

    SciTech Connect

    Van de Velde, Joris; Audenaert, Emmanuel; Speleers, Bruno; Vercauteren, Tom; Mulliez, Thomas; Vandemaele, Pieter; Achten, Eric; Kerckaert, Ingrid; D'Herde, Katharina; De Neve, Wilfried; Van Hoof, Tom

    2013-11-15

    Purpose: To develop contouring guidelines for the brachial plexus (BP) using anatomically validated cadaver datasets. Magnetic resonance imaging (MRI) and computed tomography (CT) were used to obtain detailed visualizations of the BP region, with the goal of achieving maximal inclusion of the actual BP in a small contoured volume while also accommodating for anatomic variations. Methods and Materials: CT and MRI were obtained for 8 cadavers positioned for intensity modulated radiation therapy. 3-dimensional reconstructions of soft tissue (from MRI) and bone (from CT) were combined to create 8 separate enhanced CT project files. Dissection of the corresponding cadavers anatomically validated the reconstructions created. Seven enhanced CT project files were then automatically fitted, separately in different regions, to obtain a single dataset of superimposed BP regions that incorporated anatomic variations. From this dataset, improved BP contouring guidelines were developed. These guidelines were then applied to the 7 original CT project files and also to 1 additional file, left out from the superimposing procedure. The percentage of BP inclusion was compared with the published guidelines. Results: The anatomic validation procedure showed a high level of conformity for the BP regions examined between the 3-dimensional reconstructions generated and the dissected counterparts. Accurate and detailed BP contouring guidelines were developed, which provided corresponding guidance for each level in a clinical dataset. An average margin of 4.7 mm around the anatomically validated BP contour is sufficient to accommodate for anatomic variations. Using the new guidelines, 100% inclusion of the BP was achieved, compared with a mean inclusion of 37.75% when published guidelines were applied. Conclusion: Improved guidelines for BP delineation were developed using combined MRI and CT imaging with validation by anatomic dissection.

  6. Brain Morphometry Using Anatomical Magnetic Resonance Imaging

    ERIC Educational Resources Information Center

    Bansal, Ravi; Gerber, Andrew J.; Peterson, Bradley S.

    2008-01-01

    The efficacy of anatomical magnetic resonance imaging (MRI) in studying the morphological features of various regions of the brain is described, also providing the steps used in the processing and studying of the images. The ability to correlate these features with several clinical and psychological measures can help in using anatomical MRI to…

  7. Patterns and Variations in Microvascular Decompression for Trigeminal Neuralgia

    PubMed Central

    TODA, Hiroki; GOTO, Masanori; IWASAKI, Koichi

    2015-01-01

    Microvascular decompression (MVD) is a highly effective surgical treatment for trigeminal neuralgia (TN). Although there is little prospective clinical evidence, accumulated observational studies have demonstrated the benefits of MVD for refractory TN. In the current surgical practice of MVD for TN, there have been recognized patterns and variations in surgical anatomy and various decompression techniques. Here we provide a stepwise description of surgical procedures and relevant anatomical characteristics, as well as procedural options. PMID:25925756

  8. Genetic interactions contribute less than additive effects to quantitative trait variation in yeast

    PubMed Central

    Bloom, Joshua S.; Kotenko, Iulia; Sadhu, Meru J.; Treusch, Sebastian; Albert, Frank W.; Kruglyak, Leonid

    2015-01-01

    Genetic mapping studies of quantitative traits typically focus on detecting loci that contribute additively to trait variation. Genetic interactions are often proposed as a contributing factor to trait variation, but the relative contribution of interactions to trait variation is a subject of debate. Here we use a very large cross between two yeast strains to accurately estimate the fraction of phenotypic variance due to pairwise QTL–QTL interactions for 20 quantitative traits. We find that this fraction is 9% on average, substantially less than the contribution of additive QTL (43%). Statistically significant QTL–QTL pairs typically have small individual effect sizes, but collectively explain 40% of the pairwise interaction variance. We show that pairwise interaction variance is largely explained by pairs of loci at least one of which has a significant additive effect. These results refine our understanding of the genetic architecture of quantitative traits and help guide future mapping studies. PMID:26537231

  9. Two levels ARIMAX and regression models for forecasting time series data with calendar variation effects

    NASA Astrophysics Data System (ADS)

    Suhartono, Lee, Muhammad Hisyam; Prastyo, Dedy Dwi

    2015-12-01

    The aim of this research is to develop a calendar variation model for forecasting retail sales data with the Eid ul-Fitr effect. The proposed model is based on two methods, namely two levels ARIMAX and regression methods. Two levels ARIMAX and regression models are built by using ARIMAX for the first level and regression for the second level. Monthly men's jeans and women's trousers sales in a retail company for the period January 2002 to September 2009 are used as case study. In general, two levels of calendar variation model yields two models, namely the first model to reconstruct the sales pattern that already occurred, and the second model to forecast the effect of increasing sales due to Eid ul-Fitr that affected sales at the same and the previous months. The results show that the proposed two level calendar variation model based on ARIMAX and regression methods yields better forecast compared to the seasonal ARIMA model and Neural Networks.

  10. Variation of RNA Quality and Quantity Are Major Sources of Batch Effects in Microarray Expression Data

    PubMed Central

    Fasold, Mario; Binder, Hans

    2014-01-01

    The great utility of microarrays for genome-scale expression analysis is challenged by the widespread presence of batch effects, which bias expression measurements in particular within large data sets. These unwanted technical artifacts can obscure biological variation and thus significantly reduce the reliability of the analysis results. It is largely unknown which are the predominant technical sources leading to batch effects. We here quantitatively assess the prevalence and impact of several known technical effects on microarray expression results. Particularly, we focus on important factors such as RNA degradation, RNA quantity, and sequence biases including multiple guanine effects. We find that the common variation of RNA quality and RNA quantity can not only yield low-quality expression results, but that both factors also correlate with batch effects and biological characteristics of the samples.

  11. Fabrication and Assessment of 3D Printed Anatomical Models of the Lower Limb for Anatomical Teaching and Femoral Vessel Access Training in Medicine

    ERIC Educational Resources Information Center

    O'Reilly, Michael K.; Reese, Sven; Herlihy, Therese; Geoghegan, Tony; Cantwell, Colin P.; Feeney, Robin N. M.; Jones, James F. X.

    2016-01-01

    For centuries, cadaveric dissection has been the touchstone of anatomy education. It offers a medical student intimate access to his or her first patient. In contrast to idealized artisan anatomical models, it presents the natural variation of anatomy in fine detail. However, a new teaching construct has appeared recently in which artificial…

  12. Parametric reduced-order models of battery pack vibration including structural variation and prestress effects

    NASA Astrophysics Data System (ADS)

    Hong, Sung-Kwon; Epureanu, Bogdan I.; Castanier, Matthew P.

    2014-09-01

    The goal of this work is to develop a numerical model for the vibration of hybrid electric vehicle (HEV) battery packs to enable probabilistic forced response simulations for the effects of variations. There are two important types of variations that affect their structural response significantly: the prestress that is applied when joining the cells within a pack; and the small, random structural property discrepancies among the cells of a battery pack. The main contributions of this work are summarized as follows. In order to account for these two important variations, a new parametric reduced order model (PROM) formulation is derived by employing three key observations: (1) the stiffness matrix can be parameterized for different levels of prestress, (2) the mode shapes of a battery pack with cell-to-cell variation can be represented as a linear combination of the mode shapes of the nominal system, and (3) the frame holding each cell has vibratory motion. A numerical example of an academic battery pack with pouch cells is presented to demonstrate that the PROM captures the effects of both prestress and structural variation on battery packs. The PROM is validated numerically by comparing full-order finite element models (FEMs) of the same systems.

  13. Singapore's anatomical future: quo vadis?

    PubMed

    Ang, Eng-Tat; Sugand, Kapil; Hartman, Mikael; Seow, Choon-Sheong; Bay, Boon-Huat; Abrahams, Peter

    2012-01-01

    The disciplines of anatomy and surgery are not dichotomous since one is dependent on the other. Traditionally, surgeons predominantly taught gross and clinical anatomy. In this review, we examine the context of how human anatomy is taught nowadays. In essence, we discovered that there are certain discernable trends consistently observable between the American and British systems. In Singapore, the British Russell Group first influenced its education landscape but now more so by the American Ivy League. Singapore now has three medical schools all offering differing anatomy curricula, which serves as an opportune time for it to consider if there is a best approach given that the practice of surgery is also evolving in parallel. This review discusses the various pedagogies and issues involved, and will serve as a forum and stimulus for discussion. By tweaking the curriculum correctly and the lessons learnt, future doctors and surgeons in training will receive a better anatomical education, not just in Singapore but the world in general. Key recommendations include the use of body painting, clay, plasticine to facilitate the learning of anatomy, and the implementation of a body donation program. Furthermore, strategic mergers with key stakeholders will also ensure the survival of the discipline. PMID:22566391

  14. Population genetic consequences of the Allee effect and the role of offspring-number variation.

    PubMed

    Wittmann, Meike J; Gabriel, Wilfried; Metzler, Dirk

    2014-09-01

    A strong demographic Allee effect in which the expected population growth rate is negative below a certain critical population size can cause high extinction probabilities in small introduced populations. But many species are repeatedly introduced to the same location and eventually one population may overcome the Allee effect by chance. With the help of stochastic models, we investigate how much genetic diversity such successful populations harbor on average and how this depends on offspring-number variation, an important source of stochastic variability in population size. We find that with increasing variability, the Allee effect increasingly promotes genetic diversity in successful populations. Successful Allee-effect populations with highly variable population dynamics escape rapidly from the region of small population sizes and do not linger around the critical population size. Therefore, they are exposed to relatively little genetic drift. It is also conceivable, however, that an Allee effect itself leads to an increase in offspring-number variation. In this case, successful populations with an Allee effect can exhibit less genetic diversity despite growing faster at small population sizes. Unlike in many classical population genetics models, the role of offspring-number variation for the population genetic consequences of the Allee effect cannot be accounted for by an effective-population-size correction. Thus, our results highlight the importance of detailed biological knowledge, in this case on the probability distribution of family sizes, when predicting the evolutionary potential of newly founded populations or when using genetic data to reconstruct their demographic history. PMID:25009148

  15. Effects of Variations in Toy Presentation on Social Behaviour of Infants and Toddlers in Childcare

    ERIC Educational Resources Information Center

    Shohet, Cilly; Klein, Pnina S.

    2010-01-01

    The objective of this study was to examine the effects of variations in presentation of play materials on social behaviour of 18- to 30-month-old children. The study group included 102 children attending infant and toddler classes in 14 public childcare centres in Israel. Play materials were presented to the children either in a suggestive manner…

  16. Pennies from Heaven? Using Exogenous Tax Variation to Identify Effects of School Resources on Pupil Achievement

    ERIC Educational Resources Information Center

    Haegeland, Torbjorn; Raaum, Oddbjorn; Salvanes, Kjell G.

    2012-01-01

    Evidence on the effectiveness of school inputs remains inconclusive, partly due to the challenge of identification as families sort themselves into school districts and resources are potentially allocated to compensate (or reinforce) differences in pupil abilities. Using variation in school resources induced by the location of waterfalls in…

  17. STUDIES OF THE EFFECTS OF SYSTEMATIC VARIATION OF CERTAIN CONDITIONS RELATED TO LEARNING. III. TASK CONDITIONS.

    ERIC Educational Resources Information Center

    BLAKE, KATHRYN A.; AND OTHERS

    A SERIES OF RESEARCH PROGRAMS CONCERNED WITH THE EFFECTS OF SYSTEMATIC VARIATIONS OF CERTAIN CONDITIONS RELATED TO LEARNING HAS BEEN CONDUCTED. PROJECTS PREVIOUSLY REPORTED INCLUDED TWO INVESTIGATIONS OF REINFORCEMENT AND SUBJECT VARIABLES AND ONE ON THE STUDY OF PRACTICE AND SUBJECT VARIABLES. THE NATURE OF THE OVERALL PROGRAM WAS DISCUSSED IN…

  18. The Effects of Phonological Neighborhoods on Pronunciation Variation in Conversational Speech

    ERIC Educational Resources Information Center

    Yao, Yao

    2011-01-01

    This dissertation investigates the effects of phonological neighborhoods on pronunciation variation in conversational speech. Phonological neighbors are defined as words that are different in one and only one phoneme by addition, deletion and substitution. Phonological neighborhood density refers to the number of neighbors a certain word has. …

  19. The Effects of Variations in Lesson Control and Practice on Learning from Interactive Video.

    ERIC Educational Resources Information Center

    Hannafin, Michael J.; Colamaio, MaryAnne E.

    1987-01-01

    Discussion of the effects of variations in lesson control and practice on the learning of facts, procedures, and problem-solving skills during interactive video instruction focuses on a study of graduates and advanced level undergraduates learning cardiopulmonary resuscitation (CPR). Embedded questioning methods and posttests used are described.…

  20. Principal Stratification: A Tool for Understanding Variation in Program Effects across Endogenous Subgroups

    ERIC Educational Resources Information Center

    Page, Lindsay C.; Feller, Avi; Grindal, Todd; Miratrix, Luke; Somers, Marie-Andree

    2015-01-01

    Increasingly, researchers are interested in questions regarding treatment-effect variation across partially or fully latent subgroups defined not by pretreatment characteristics but by postrandomization actions. One promising approach to address such questions is principal stratification. Under this framework, a researcher defines endogenous…

  1. Variations in Latino Parenting Practices and Their Effects on Child Cognitive Developmental Outcomes

    ERIC Educational Resources Information Center

    De Von Figueroa-Moseley, Colmar; Ramey, Craig T.; Keltner, Bette; Lanzi, Robin G.

    2006-01-01

    This research examines variations in parenting and its effects on child cognitive outcomes across Latino subgroups from a national sampling that utilized a subset of 995 former Head Start Latino parents and children. Comparisons of the Parenting Dimension Inventory scaled scores revealed Latino subgroup differences on nurturance and consistency.…

  2. 40 CFR 53.56 - Test for effect of variations in ambient pressure.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 6 2013-07-01 2013-07-01 false Test for effect of variations in ambient pressure. 53.56 Section 53.56 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) AMBIENT AIR MONITORING REFERENCE AND EQUIVALENT METHODS Procedures for Testing Physical (Design) and...

  3. Effects of the variation of fundamental constants on Pop III stellar evolution

    SciTech Connect

    Coc, A.; Descouvemont, P.; Uzan, J.-Ph.; Vangioni, E.

    2010-08-12

    The effect of variations of the fundamental constants on the thermonuclear rate of the triple alpha reaction, {sup 4}He({alpha}{alpha}, {gamma}){sup 12}C, that bridges the gap between {sup 4}He and {sup 12}C is investigated. We have followed the evolution of 15 and 60 M{center_dot} zero metallicity stellar models, up to the end of core helium burning. They are assumed to be representative of the first (Population III) stars. The calculated oxygen carbon abundances resulting from helium burning can then be used to constrain the variation of the fundamental constants.

  4. Variational method of determining effective moduli of polycrystals with tetragonal symmetry

    USGS Publications Warehouse

    Meister, R.; Peselnick, L.

    1966-01-01

    Variational principles have been applied to aggregates of randomly oriented pure-phase polycrystals having tetragonal symmetry. The bounds of the effective elastic moduli obtained in this way show a substantial improvement over the bounds obtained by means of the Voigt and Reuss assumptions. The Hill average is found to be a good approximation in most cases when compared to the bounds found from the variational method. The new bounds reduce in their limits to the Voigt and Reuss values. ?? 1966 The American Institute of Physics.

  5. Variational method of determining effective moduli of polycrystals: (A) hexagonal symmetry, (B) trigonal symmetry

    USGS Publications Warehouse

    Peselnick, L.; Meister, R.

    1965-01-01

    Variational principles of anisotropic elasticity have been applied to aggregates of randomly oriented pure-phase polycrystals having hexagonal symmetry and trigonal symmetry. The bounds of the effective elastic moduli obtained in this way show a considerable improvement over the bounds obtained by means of the Voigt and Reuss assumptions. The Hill average is found to be in most cases a good approximation when compared to the bounds found from the variational method. The new bounds reduce in their limits to the Voigt and Reuss values. ?? 1965 The American Institute of Physics.

  6. Plant genetic variation mediates an indirect ecological effect between belowground earthworms and aboveground aphids

    PubMed Central

    2014-01-01

    Background Interactions between aboveground and belowground terrestrial communities are often mediated by plants, with soil organisms interacting via the roots and aboveground organisms via the shoots and leaves. Many studies now show that plant genetics can drive changes in the structure of both above and belowground communities; however, the role of plant genetic variation in mediating aboveground-belowground interactions is still unclear. We used an earthworm-plant-aphid model system with two aphid species (Aphis fabae and Acyrthosiphon pisum) to test the effect of host-plant (Vicia faba) genetic variation on the indirect interaction between the belowground earthworms (Eisenia veneta) on the aboveground aphid populations. Results Our data shows that host-plant variety mediated an indirect ecological effect of earthworms on generalist black bean aphids (A. fabae), with earthworms increasing aphid growth rate in three plant varieties but decreasing it in another variety. We found no effect of earthworms on the second aphid species, the pea aphid (A. pisum), and no effect of competition between the aphid species. Plant biomass was increased when earthworms were present, and decreased when A. pisum was feeding on the plant (mediated by plant variety). Although A. fabae aphids were influenced by the plants and worms, they did not, in turn, alter plant biomass. Conclusions Previous work has shown inconsistent effects of earthworms on aphids, but we suggest these differences could be explained by plant genetic variation and variation among aphid species. This study demonstrates that the outcome of belowground-aboveground interactions can be mediated by genetic variation in the host-plant, but depends on the identity of the species involved. PMID:25331082

  7. Effect of Helical Slow-Wave Circuit Variations on TWT Cold-Test Characteristics

    NASA Technical Reports Server (NTRS)

    Kory, Carol L.; Dayton, James A., Jr.

    1997-01-01

    Recent advances in the state of the art of computer modeling offer the possibility for the first time to evaluate the effect that slow-wave structure parameter variations, such as manufacturing tolerances, have on the cold-test characteristics of helical traveling-wave tubes (TWT's). This will enable manufacturers to determine the cost effectiveness of controlling the dimensions of the component parts of the TWT, which is almost impossible to do experimentally without building a large number of tubes and controlling several parameters simultaneously. The computer code MAFIA is used in this analysis to determine the effect on dispersion and on-axis interaction impedance of several helical slow-wave circuit parameter variations, including thickness and relative dielectric constant of the support rods, tape width, and height of the metallized films deposited on the dielectric rods. Previous computer analyses required so many approximations that accurate determinations of the effect of many relevant dimensions on tube performance were practically impossible.

  8. Effect of Helical Slow-Wave Circuit Variations on TWT Cold-Test Characteristics

    NASA Technical Reports Server (NTRS)

    Kory, Carol L.; Dayton, J. A., Jr.

    1998-01-01

    Recent advances in the state of the art of computer modeling offer the possibility for the first time to evaluate the effect that slow-wave structure parameter variations, such as manufacturing tolerances, have on the cold-test characteristics of helical traveling-wave tubes (TWT's). This will enable manufacturers to determine the cost effectiveness of controlling the dimensions of the component parts of the TWT, which is almost impossible to do experimentally without building a large number of tubes and controlling several parameters simultaneously. The computer code MAFIA is used in this analysis to determine the effect on dispersion and on-axis interaction impedance of several helical slow-wave circuit parameter variations, including thickness and relative dielectric constant of the support rods, tape width, and height of the metallized films deposited on the dielectric rods. Previous computer analyzes required so many approximations that accurate determinations of the effect of many relevant dimensions on tube performance were practically impossible.

  9. Effect of variation in ovine WFIKKN2 on growth traits appears to be gender-dependent

    PubMed Central

    Wang, Jiqing; Zhou, Huitong; Fang, Qian; Liu, Xiu; Luo, Yuzhu; Hickford, Jon G. H.

    2015-01-01

    WFIKKN2 may play a role in the regulation of muscle growth and development, but to date there have been no reports on the effect of variation in WFIKKN2 on growth and carcass traits in livestock. In this study, the effect of variation in ovine WFIKKN2 was investigated in 800 New Zealand Romney lambs (395 male and 405 female), with five previously described variants (A to E) being identified. Variation in ovine WFIKKN2 was not found to affect various growth traits in the female lambs, but the presence of variant B was associated (P < 0.05) with decreased birth weight, tailing weight, weaning weight and pre-weaning growth rate; and increased post-weaning growth rate in male lambs. In male lambs, the presence of variant B was associated (P < 0.05) with an increased shoulder yield and proportion shoulder yield. No associations with growth or carcass traits were detected for the presence (or absence) of the other variants. These results suggest that variation in ovine WFIKKN2 may have a differential effect on growth in male and female lambs, and hence that the gene may be expressed in, or act in, a gender-specific fashion. PMID:26197924

  10. Analytical model for effect of temperature variation on PSF consistency in wavefront coding infrared imaging system

    NASA Astrophysics Data System (ADS)

    Feng, Bin; Shi, Zelin; Zhang, Chengshuo; Xu, Baoshu; Zhang, Xiaodong

    2016-05-01

    The point spread function (PSF) inconsistency caused by temperature variation leads to artifacts in decoded images of a wavefront coding infrared imaging system. Therefore, this paper proposes an analytical model for the effect of temperature variation on the PSF consistency. In the proposed model, a formula for the thermal deformation of an optical phase mask is derived. This formula indicates that a cubic optical phase mask (CPM) is still cubic after thermal deformation. A proposed equivalent cubic phase mask (E-CPM) is a virtual and room-temperature lens which characterizes the optical effect of temperature variation on the CPM. Additionally, a calculating method for PSF consistency after temperature variation is presented. Numerical simulation illustrates the validity of the proposed model and some significant conclusions are drawn. Given the form parameter, the PSF consistency achieved by a Ge-material CPM is better than the PSF consistency by a ZnSe-material CPM. The effect of the optical phase mask on PSF inconsistency is much slighter than that of the auxiliary lens group. A large form parameter of the CPM will introduce large defocus-insensitive aberrations, which improves the PSF consistency but degrades the room-temperature MTF.

  11. Effect of variation in ovine WFIKKN2 on growth traits appears to be gender-dependent.

    PubMed

    Wang, Jiqing; Zhou, Huitong; Fang, Qian; Liu, Xiu; Luo, Yuzhu; Hickford, Jon G H

    2015-01-01

    WFIKKN2 may play a role in the regulation of muscle growth and development, but to date there have been no reports on the effect of variation in WFIKKN2 on growth and carcass traits in livestock. In this study, the effect of variation in ovine WFIKKN2 was investigated in 800 New Zealand Romney lambs (395 male and 405 female), with five previously described variants (A to E) being identified. Variation in ovine WFIKKN2 was not found to affect various growth traits in the female lambs, but the presence of variant B was associated (P < 0.05) with decreased birth weight, tailing weight, weaning weight and pre-weaning growth rate; and increased post-weaning growth rate in male lambs. In male lambs, the presence of variant B was associated (P < 0.05) with an increased shoulder yield and proportion shoulder yield. No associations with growth or carcass traits were detected for the presence (or absence) of the other variants. These results suggest that variation in ovine WFIKKN2 may have a differential effect on growth in male and female lambs, and hence that the gene may be expressed in, or act in, a gender-specific fashion. PMID:26197924

  12. The Study of Effects of Time Variations in the Earth's Gravity Field on Geodetic Satellites

    NASA Technical Reports Server (NTRS)

    Shum, C. K.

    1998-01-01

    The temporal variations in the Earth's gravity field are the consequences of complex interactions between atmosphere, ocean, solid Earth, hydrosphere and cryosphere. The signal ranges from several hours to 18.6 years to geological time scale. The direct and indirect consequences of these variations are manifested in such phenomena as changes in the global sea level and in the global climate pattern. These signals produce observable geodetic satellites. The primary objectives of the proposed effects on near-Earth orbiting investigation include (1) the improved determination of the time-varying gravity field parameters (scale from a few hour to 18.6 year and secular) using long-term satellite laser rs ranging (SLR) observations to multiple geodetic satellites, and (2) the enhanced understanding of these variations with their associated meteorological and geophysical consequences.

  13. The anatomical school of Padua.

    PubMed

    Porzionato, Andrea; Macchi, Veronica; Stecco, Carla; Parenti, Anna; De Caro, Raffaele

    2012-06-01

    The University of Padua is one of the most ancient in the world, being founded in 1222, and the most important anatomists of the XVI, XVII, and XVIII centuries studied and taught here. Probably, the first professor of anatomy and surgery was Bruno da Longobucco (c. 1200-c. 1286), who had previously studied at the Salerno School of Medicine. While professor in Padua, Andreas Vesalius (1514-1564) published De Humani Corporis Fabrica (1543), which is considered as the birth of the modern anatomy. Following professors were Realdo Colombo (c. 1516-1559), Gabriel Fallopius (1523-1562), Hieronymus Fabricius ab Aquapendente (1533-1619), Iulius Casserius (1552-1616), Johann Wesling (1598-1649), and Johann Georg Wirsung (1589-1643). Many other foreign scholars studied in the University of Padua, such as Thomas Linacre (c. 1460-1524), the founder of the Royal College of Physicians, Werner Rolfinck (1599-1673), and Olof Rudbeck (1630-1702), who created anatomical theatres in Germany and Sweden, respectively, on the basis of the Paduan model. The anatomy of the XVII century characteristically widened the scope of its enquiry to function, as in the Exercitatio Anatomica De Motu Cordis et Sanguinis in Animalibus (1628) by William Harvey (1578-1657). Further evolution was then given by the anatomy in the XVIII century, which tried to correlate alterations of structure with clinical symptoms. The most important anatomist of this century is Giovanni Battista Morgagni (1682-1771), whose masterpiece De Sedibus et Causis Morborum per Anatomen Indagatis (1761) is a landmark contribution that is viewed as the beginning of modern pathologic anatomy. This year falls the 300th anniversary of Morgagni's inaugural lecture on medical education, Nova Institutionum Medicarum Idea (1712), which is still relevant in its effort to stress the importance of a deep knowledge of all the preclinical and clinical aspects of medical science. PMID:22581496

  14. Effects of founding genetic variation on adaptation to a novel resource.

    PubMed

    Agashe, Deepa; Falk, Jay J; Bolnick, Daniel I

    2011-09-01

    Population genetic theory predicts that adaptation in novel environments is enhanced by genetic variation for fitness. However, theory also predicts that under strong selection, demographic stochasticity can drive populations to extinction before they can adapt. We exposed wheat-adapted populations of the flour beetle (Tribolium castaneum) to a novel suboptimal corn resource, to test the effects of founding genetic variation on population decline and subsequent extinction or adaptation. As previously reported, genetically diverse populations were less likely to go extinct. Here, we show that among surviving populations, genetically diverse groups recovered faster after the initial population decline. Within two years, surviving populations significantly increased their fitness on corn via increased fecundity, increased egg survival, faster larval development, and higher rate of egg cannibalism. However, founding genetic variation only enhanced the increase in fecundity, despite existing genetic variation-and apparent lack of trade-offs-for egg survival and larval development time. Thus, during adaptation to novel habitats the positive impact of genetic variation may be restricted to only a few traits, although change in many life-history traits may be necessary to avoid extinction. Despite severe initial maladaptation and low population size, genetic diversity can thus overcome the predicted high extinction risk in new habitats. PMID:21884051

  15. Effects of temperature variations on guided waves propagating in composite structures

    NASA Astrophysics Data System (ADS)

    Shoja, Siavash; Berbyuk, Viktor; Boström, Anders

    2016-04-01

    Effects of temperature on guided waves propagating in composite materials is a well-known problem which has been investigated in many studies. The majority of the studies is focused on effects of high temperature. Understanding the effects of low temperature has major importance in composite structures and components which are operating in cold climate conditions such as e.g. wind turbines operating in cold climate regions. In this study first the effects of temperature variations on guided waves propagating in a composite plate is investigated experimentally in a cold climate chamber. The material is a common material used to manufacture rotor blades of wind turbines. The temperature range is 25°C to -25°C and effects of temperature variations on amplitude and phase shift of the received signal are investigated. In order to apply the effects of lowering the temperature on the received signal, the Baseline Signal Stretch (BSS) method is modified and used. The modification is based on decomposing the signal into symmetric and asymmetric modes and applying two different stretch factors on each of them. Finally the results obtained based on the new method is compared with the results of application of BSS with one stretch factor and experimental measurements. Comparisons show that an improvement is obtained using the BSS with the mode decomposition method at temperature variations of more than 25°C.

  16. Effects of Variations of Flow and Heart Rate on Intra-Aneurysmal Hemodynamics in a Ruptured Internal Carotid Artery Aneurysm During Exercise

    PubMed Central

    Sarrami-Foroushani, Ali; Nasr Esfahany, Mohsen; Saligheh Rad, Hamidreza; Firouznia, Kavous; Shakiba, Madjid; Ghanaati, Hossein

    2016-01-01

    Background: Hemodynamics is thought to play an important role in the mechanisms responsible for initiation, growth, and rupture of intracranial aneurysms. Computational fluid dynamic (CFD) analysis is used to assess intra-aneurysmal hemodynamics. Objectives: This study aimed to investigate the effects of variations in heart rate and internal carotid artery (ICA) flow rate on intra-aneurysmal hemodynamics, in an ICA aneurysm, by using computational fluid dynamics. Patients and Methods: Computed tomography angiography (CTA) was performed in a 55 years old female case, with a saccular ICA aneurysm, to create a patient-specific geometrical anatomic model of the aneurysm. The intra-aneurysmal hemodynamic environments for three states with different flow and heart rates were analyzed using patient-specific image-based CFD modeling. Results: Results showed significant changes for the three simulated states. For a proportion of the states examined, results were counterintuitive. Systolic and time-averaged wall shear stress and pressure on the aneurysm wall showed a proportional evolution with the mainstream flow rate. Conclusion: Results reinforced the pivotal role of vascular geometry, with respect to hemodynamics, together with the importance of performing patient-specific CFD analyses, through which the effect of different blood flow conditions on the aneurysm hemodynamics could be evaluated. PMID:27110332

  17. A practical guide and power analysis for GLMMs: detecting among treatment variation in random effects

    PubMed Central

    Bolker, Ben M.; McCoy, Michael W.

    2015-01-01

    In ecology and evolution generalized linear mixed models (GLMMs) are becoming increasingly used to test for differences in variation by treatment at multiple hierarchical levels. Yet, the specific sampling schemes that optimize the power of an experiment to detect differences in random effects by treatment/group remain unknown. In this paper we develop a blueprint for conducting power analyses for GLMMs focusing on detecting differences in variance by treatment. We present parameterization and power analyses for random-intercepts and random-slopes GLMMs because of their generality as focal parameters for most applications and because of their immediate applicability to emerging questions in the field of behavioral ecology. We focus on the extreme case of hierarchically structured binomial data, though the framework presented here generalizes easily to any error distribution model. First, we determine the optimal ratio of individuals to repeated measures within individuals that maximizes power to detect differences by treatment in among-individual variation in intercept, among-individual variation in slope, and within-individual variation in intercept. Second, we explore how power to detect differences in target variance parameters is affected by total variation. Our results indicate heterogeneity in power across ratios of individuals to repeated measures with an optimal ratio determined by both the target variance parameter and total sample size. Additionally, power to detect each variance parameter was low overall (in most cases >1,000 total observations per treatment needed to achieve 80% power) and decreased with increasing variance in non-target random effects. With growing interest in variance as the parameter of inquiry, these power analyses provide a crucial component for designing experiments focused on detecting differences in variance. We hope to inspire novel experimental designs in ecology and evolution investigating the causes and implications of

  18. Climate alters intraspecific variation in copepod effect traits through pond food webs.

    PubMed

    Charette, Cristina; Derry, Alison M

    2016-05-01

    Essential fatty acids (EFAs) are primarily generated by phytoplankton in aquatic ecosystems, and can limit the growth, development, and reproduction of higher consumers. Among the most critical of the EFAs are highly unsaturated fatty acids (HUFAs), which are only produced by certain groups of phytoplankton. Changing environmental conditions can alter phytoplankton community and fatty acid composition and affect the HUFA content of higher trophic levels. Almost no research has addressed intraspecific variation in HUFAs in zooplankton, nor intraspecific relationships of HUFAs with body size and fecundity. This is despite that intraspecific variation in HUFAs can exceed interspecific variation and that intraspecific trait variation in body size and fecundity is increasingly recognized to have an important role in food web ecology (effect traits). Our study addressed the relative influences of abiotic selection and food web effects associated with climate change on intraspecific differences and interrelationships between HUFA content, body size, and fecundity of freshwater copepods. We applied structural equation modeling and regression analyses to intraspecific variation in a dominant calanoid copepod, Leptodiatomus minutus, among a series of shallow north-temperate ponds. Climate-driven diurnal temperature fluctuations favored the coexistence of diversity of phytoplankton groups with different temperature optima and nutritive quality. This resulted in unexpected positive relationships between temperature, copepod DHA content and body size. Temperature correlated positively with diatom biovolume, and mediated relationships between copepod HUFA content and body size, and between copepod body size and fecundity. The presence of brook trout further accentuated these positive effects in warm ponds, likely through nutrient cycling and stimulation of phytoplankton resources. Climate change may have previously unrecognized positive effects on freshwater copepod DHA content

  19. Long-term Cost-Effectiveness of Diagnostic Tests for Assessing Stable Chest Pain: Modeled Analysis of Anatomical and Functional Strategies.

    PubMed

    Bertoldi, Eduardo G; Stella, Steffan F; Rohde, Luis E; Polanczyk, Carisi A

    2016-05-01

    Several tests exist for diagnosing coronary artery disease, with varying accuracy and cost. We sought to provide cost-effectiveness information to aid physicians and decision-makers in selecting the most appropriate testing strategy. We used the state-transitions (Markov) model from the Brazilian public health system perspective with a lifetime horizon. Diagnostic strategies were based on exercise electrocardiography (Ex-ECG), stress echocardiography (ECHO), single-photon emission computed tomography (SPECT), computed tomography coronary angiography (CTA), or stress cardiac magnetic resonance imaging (C-MRI) as the initial test. Systematic review provided input data for test accuracy and long-term prognosis. Cost data were derived from the Brazilian public health system. Diagnostic test strategy had a small but measurable impact in quality-adjusted life-years gained. Switching from Ex-ECG to CTA-based strategies improved outcomes at an incremental cost-effectiveness ratio of 3100 international dollars per quality-adjusted life-year. ECHO-based strategies resulted in cost and effectiveness almost identical to CTA, and SPECT-based strategies were dominated because of their much higher cost. Strategies based on stress C-MRI were most effective, but the incremental cost-effectiveness ratio vs CTA was higher than the proposed willingness-to-pay threshold. Invasive strategies were dominant in the high pretest probability setting. Sensitivity analysis showed that results were sensitive to costs of CTA, ECHO, and C-MRI. Coronary CT is cost-effective for the diagnosis of coronary artery disease and should be included in the Brazilian public health system. Stress ECHO has a similar performance and is an acceptable alternative for most patients, but invasive strategies should be reserved for patients at high risk. PMID:27080921

  20. Glucose sensing using the Brewster reflection: polarimetric ray-tracing based upon an anatomical eye model

    NASA Astrophysics Data System (ADS)

    Bockle, Stefan; Rovati, Luigi; Ansari, Rafat R.

    2003-07-01

    In this paper we present theoretical analysis to support the polarimetric approach for glucose detection in the human eye applying Brewster reflection off the ocular lens. The theoretical eye model of Navarro, which is based upon anatomical data, was used to perform ray-tracing, whereas the electromagnetic and polarization parameters of light propagation through the eye-media were calculated. The errors in glucose concentration determination due to refraction and deviation from the ideal optical path were calculated under different conditions. Effects of using incident linearly and circularly polarized light and variation of intersection condition of the incoming light beam with the anterior corneal surface were taken into consideration. Calculations were performed for a wide spectral range by applying dispersion curves for the eye-media. These simulations show the potential and the limits of the proposed optical approach.

  1. The effect of conjunctions on the transit timing variations of exoplanets

    SciTech Connect

    Nesvorný, David; Vokrouhlický, David E-mail: vokrouhl@cesnet.cz

    2014-07-20

    We develop an analytic model for transit timing variations produced by orbital conjunctions between gravitationally interacting planets. If the planetary orbits have tight orbital spacing, which is a common case among the Kepler planets, the effect of a single conjunction can be best described as: (1) a step-like change of the transit timing ephemeris with subsequent transits of the inner planet being delayed and those of the outer planet being sped up, and (2) a discrete change in sampling of the underlying oscillations from eccentricity-related interaction terms. In the limit of small orbital eccentricities, our analytic model gives explicit equations for these effects as a function of the mass and orbital separation of planets. We point out that a detection of the conjunction effect in real data is of crucial importance for the physical characterization of planetary systems from transit timing variations.

  2. Effects of maternal characteristics and climatic variation on birth masses of Alaskan caribou

    USGS Publications Warehouse

    Adams, L.G.

    2005-01-01

    Understanding factors that influence birth mass of mammals provides insights to nutritional trade-offs made by females to optimize their reproduction, growth, and survival. I evaluated variation in birth mass of caribou (Rangifer tarandus) in central Alaska relative to maternal characteristics (age, body mass, cohort, and nutritional condition as influenced by winter severity) during 11 years with substantial variation in winter snowfall. Snowfall during gestation was the predominant factor explaining variation in birth masses, influencing birth mass inversely and through interactions with maternal age and lactation status. Maternal age effects were noted for females ??? 5 years old, declining in magnitude with each successive age class. Birth mass as a proportion of autumn maternal mass was inversely related to winter snowfall, even though there was no decrease in masses of adult females in late winter associated with severe winters. I found no evidence of a hypothesized intergenerational effect of lower birth masses for offspring of females born after severe winters. Caribou produce relatively small offspring but provide exceptional lactation support for those that survive. Conservative maternal investment before parturition may represent an optimal reproductive strategy given that caribou experience stochastic variation in winter severity during gestation, uncertainty of environmental conditions surrounding the birth season, and intense predation on neonates. ?? 2005 American Society of Mammalogists.

  3. Sex ratio variation shapes the ecological effects of a globally introduced freshwater fish.

    PubMed

    Fryxell, David C; Arnett, Heather A; Apgar, Travis M; Kinnison, Michael T; Palkovacs, Eric P

    2015-10-22

    Sex ratio and sexual dimorphism have long been of interest in population and evolutionary ecology, but consequences for communities and ecosystems remain untested. Sex ratio could influence ecological conditions whenever sexual dimorphism is associated with ecological dimorphism in species with strong ecological interactions. We tested for ecological implications of sex ratio variation in the sexually dimorphic western mosquitofish, Gambusia affinis. This species causes strong pelagic trophic cascades and exhibits substantial variation in adult sex ratios. We found that female-biased populations induced stronger pelagic trophic cascades compared with male-biased populations, causing larger changes to key community and ecosystem responses, including zooplankton abundance, phytoplankton abundance, productivity, pH and temperature. The magnitude of such effects indicates that sex ratio is important for mediating the ecological role of mosquitofish. Because both sex ratio variation and sexual dimorphism are common features of natural populations, our findings should encourage broader consideration of the ecological significance of sex ratio variation in nature, including the relative contributions of various sexually dimorphic traits to these effects. PMID:26490793

  4. Major-Effect Alleles at Relatively Few Loci Underlie Distinct Vernalization and Flowering Variation in Arabidopsis Accessions

    PubMed Central

    Lister, Clare; Anderson, Jillian; Warthmann, Norman; Shindo, Chikako; Irwin, Judith; Nordborg, Magnus; Dean, Caroline

    2011-01-01

    We have explored the genetic basis of variation in vernalization requirement and response in Arabidopsis accessions, selected on the basis of their phenotypic distinctiveness. Phenotyping of F2 populations in different environments, plus fine mapping, indicated possible causative genes. Our data support the identification of FRI and FLC as candidates for the major-effect QTL underlying variation in vernalization response, and identify a weak FLC allele, caused by a Mutator-like transposon, contributing to flowering time variation in two N. American accessions. They also reveal a number of additional QTL that contribute to flowering time variation after saturating vernalization. One of these was the result of expression variation at the FT locus. Overall, our data suggest that distinct phenotypic variation in the vernalization and flowering response of Arabidopsis accessions is accounted for by variation that has arisen independently at relatively few major-effect loci. PMID:21625501

  5. Anatomical Basis for the Cardiac Interventional Electrophysiologist

    PubMed Central

    Sánchez-Quintana, Damián; Doblado-Calatrava, Manuel; Cabrera, José Angel; Macías, Yolanda; Saremi, Farhood

    2015-01-01

    The establishment of radiofrequency catheter ablation techniques as the mainstay in the treatment of tachycardia has renewed new interest in cardiac anatomy. The interventional arrhythmologist has drawn attention not only to the gross anatomic details of the heart but also to architectural and histological characteristics of various cardiac regions that are relevant to the development or recurrence of tachyarrhythmias and procedural related complications of catheter ablation. In this review, therefore, we discuss some anatomic landmarks commonly used in catheter ablations including the terminal crest, sinus node region, Koch's triangle, cavotricuspid isthmus, Eustachian ridge and valve, pulmonary venous orifices, venoatrial junctions, and ventricular outflow tracts. We also discuss the anatomical features of important structures in the vicinity of the atria and pulmonary veins, such as the esophagus and phrenic nerves. This paper provides basic anatomic information to improve understanding of the mapping and ablative procedures for cardiac interventional electrophysiologists. PMID:26665006

  6. Anatomic Considerations in Frontal Sinus Surgery.

    PubMed

    Folbe, Adam J; Svider, Peter F; Eloy, Jean Anderson

    2016-08-01

    Comprehension of the complex anatomic variants comprising the frontal sinus outflow tract is essential for successful surgical intervention. Deviation from sound technique increases the potential for a variety of deleterious sequelae, including recurrent disease as well as catastrophic intracranial and orbital injury. Furthermore, incomplete removal of elements occluding the frontal recess can result in severe stenosis that can increase the difficulty of further interventions. This review covers anatomic considerations that should be kept in mind when performing frontal sinus surgery. PMID:27329978

  7. Effects of salinity and anatomical hook location on the mortality and physiological response of angled-and-released sand whiting Sillago ciliata.

    PubMed

    McGrath, S P; Butcher, P A; Broadhurst, M K

    2009-01-01

    Three experiments were done with sand whiting Sillago ciliata: the first two assessed the short-term mortality and physiological response of individuals after being mouth hooked and then subjected to rapid changes in salinity, while the third experiment investigated their longer-term fate after ingesting hooks (independent of salinity changes). In experiment one, 48 tanks containing a single S. ciliata were randomly assigned as either one of three treatments or a control. The fish in treatments one and two were exposed to salinity changes during their angling and subsequent release while those in treatment three were only subjected to angling and air exposure. Control fish remained untouched. Fish were then monitored for up to 6 days for mortalities before blood samples were taken to determine concentrations of plasma cortisol and glucose. Blood samples were also taken from five wild-caught fish to provide baseline estimates of the above variables. None of the treatment or control fish died over the 6 days, and there were no significant differences in blood cortisol or glucose between treatment, control and wild fish. In experiment two, 102 S. ciliata and 52 experimental tanks were used. The treatments were repeated as above, however, six individuals from each treatment and control group were removed and sampled for blood (and then glucose and cortisol) at 0, 24, 48 and 72 h post release. Some changes in behaviour due to the salinity changes occurred as well as a significant main effect of time for cortisol, with all fish having significantly elevated acute stress at the first sample time. In experiment three, 52 S. ciliata were placed into individual tanks. Twenty-six of these fish were allowed to ingest baited J-hooks, played for 60 s, removed from their tanks, and then released after their lines were cut (50 mm from their mouths). Control fish were not touched. All fish were then monitored over 21 days. Six of the treatment fish died (between 3 h and 14 days

  8. [Establishment of anatomical terminology in Japan].

    PubMed

    Shimada, Kazuyuki

    2008-12-01

    The history of anatomical terminology in Japan began with the publication of Waran Naikei Ihan-teimŏ in 1805 and Chŏtei Kaitai Shinsho in 1826. Although the establishment of Japanese anatomical terminology became necessary during the Meiji era when many western anatomy books imported into Janan were translated, such terminology was not unified during this period and varied among translators. In 1871, Tsukumo Ono's Kaibŏgaku Gosen was published by the Ministry of Education. Although this book is considered to be the first anatomical glossary terms in Japan, its contents were incomplete. Overseas, the German Anatomical Society established a unified anatomical terminology in 1895 called the Basle Nomina Anatomica (B.N.A.). Based on this development, Kaibŏgaku Meishŭ which follows the BNA, by Buntarŏ Suzuki was published in 1905. With the subsequent establishment in 1935 of Jena Nomina Anatomica (J.N.A.), the unification of anatomical terminology was also accelerated in Japan, leading to the further development of terminology. PMID:19108488

  9. Pulse-echo ultrasonic imaging method for eliminating sample thickness variation effects

    NASA Technical Reports Server (NTRS)

    Roth, Don J. (Inventor)

    1995-01-01

    A pulse-echo, immersion method for ultrasonic evaluation of a material is discussed. It accounts for and eliminates nonlevelness in the equipment set-up and sample thickness variation effects employs a single transducer, automatic scanning and digital imaging to obtain an image of a property of the material, such as pore fraction. The nonlevelness and thickness variation effects are accounted for by pre-scan adjusments of the time window to insure that the echoes received at each scan point are gated in the center of the window. This information is input into the scan file so that, during the automatic scanning for the material evaluation, each received echo is centered in its time window. A cross-correlation function calculates the velocity at each scan point, which is then proportionalized to a color or grey scale and displayed on a video screen.

  10. Long-term changes in Jovian synchrotron radio emission - Intrinsic variations or effects of viewing geometry?

    NASA Astrophysics Data System (ADS)

    Hood, L. L.

    1993-04-01

    Possible causes of the observed long-term variation of Jovian synchrotron radio emission, including both intrinsic changes in the Jovian radiation belts and apparent changes due to variations in the Jovigraphic declination of the earth, DE, are investigated. An increase in diffusion rate with other parameters held constant results in an inward displacement of the peak emission radial distance that is not observed. Effects of viewing geometry changes are examined. The possible importance of such effects is suggested by a correlation between the total decimetric radio flux and DE, which varies between -3.3 and +3.3 deg during one Jovian orbital period. Because the Jovian central meridian longitudes where the magnetic latitude passes through zero during a given Jovian rotation change substantially with DE and since significant longitudinal asymmetries exist in both the volume emissivity and the latitudinal profile of the beam, the total intensity should be at least a partial function of D sub E.

  11. Pulse-Echo Ultrasonic Imaging Method for Eliminating Sample Thickness Variation Effects

    NASA Technical Reports Server (NTRS)

    Roth, Don J. (Inventor)

    1997-01-01

    A pulse-echo, immersion method for ultrasonic evaluation of a material which accounts for and eliminates nonlevelness in the equipment set-up and sample thickness variation effects employs a single transducer and automatic scanning and digital imaging to obtain an image of a property of the material, such as pore fraction. The nonlevelness and thickness variation effects are accounted for by pre-scan adjustments of the time window to insure that the echoes received at each scan point are gated in the center of the window. This information is input into the scan file so that, during the automatic scanning for the material evaluation, each received echo is centered in its time window. A cross-correlation function calculates the velocity at each scan point, which is then proportionalized to a color or grey scale and displayed on a video screen.

  12. Sociogeographic Variation in the Effects of Heat and Cold on Daily Mortality in Japan

    PubMed Central

    Ng, Chris Fook Sheng; Ueda, Kayo; Takeuchi, Ayano; Nitta, Hiroshi; Konishi, Shoko; Bagrowicz, Rinako; Watanabe, Chiho; Takami, Akinori

    2014-01-01

    Background Ambient temperature affects mortality in susceptible populations, but regional differences in this association remain unclear in Japan. We conducted a time-series study to examine the variation in the effects of ambient temperature on daily mortality across Japan. Methods A total of 731 558 all-age non-accidental deaths in 6 cities during 2002–2007 were analyzed. The association between daily mortality and ambient temperature was examined using distributed lag nonlinear models with Poisson distribution. City-specific estimates were combined using random-effects meta-analysis. Bivariate random-effects meta-regressions were used to examine the moderating effect of city characteristics. Results The effect of heat generally persisted for 1 to 2 days. In warmer communities, the effect of cold weather lasted for approximately 1 week. The combined increases in mortality risk due to heat (99th vs 90th percentile of city-specific temperature) and cold (first vs 10th percentile) were 2.21% (95% CI, 1.38%–3.04%) and 3.47% (1.75%–5.21%), respectively. City-specific effects based on absolute temperature changes were more heterogeneous than estimates based on relative changes, which suggests some degree of acclimatization. Northern populations with a cool climate appeared acclimatized to low temperature but were still vulnerable to extreme cold weather. Population density, average income, cost of property rental, and number of nurses appeared to influence variation in heat effect across cities. Conclusions We noted clear regional variation in temperature-related increases in mortality risk, which should be considered when planning preventive measures. PMID:24317342

  13. Genetic variation for parental effects on the propensity to gregarise in Locusta migratoria

    PubMed Central

    2008-01-01

    Background Environmental parental effects can have important ecological and evolutionary consequences, yet little is known about genetic variation among populations in the plastic responses of offspring phenotypes to parental environmental conditions. This type of variation may lead to rapid phenotypic divergence among populations and facilitate speciation. With respect to density-dependent phenotypic plasticity, locust species (Orthoptera: family Acrididae), exhibit spectacular developmental and behavioural shifts in response to population density, called phase change. Given the significance of phase change in locust outbreaks and control, its triggering processes have been widely investigated. Whereas crowding within the lifetime of both offspring and parents has emerged as a primary causal factor of phase change, less is known about intraspecific genetic variation in the expression of phase change, and in particular in response to the parental environment. We conducted a laboratory experiment that explicitly controlled for the environmental effects of parental rearing density. This design enabled us to compare the parental effects on offspring expression of phase-related traits between two naturally-occurring, genetically distinct populations of Locusta migratoria that differed in their historical patterns of high population density outbreak events. Results We found that locusts from a historically outbreaking population of L. migratoria expressed parentally-inherited density-dependent phase changes to a greater degree than those from a historically non-outbreaking population. Conclusion Because locusts from both populations were raised in a common environment during our experiment, a genetically-based process must be responsible for the observed variation in the propensity to express phase change. This result emphasizes the importance of genetic factors in the expression of phase traits and calls for further investigations on density-dependent parental effects

  14. Enhanced effect of temporal variation of the fine-structure constant in diatomic molecules

    SciTech Connect

    Flambaum, V. V.

    2006-03-15

    We show that the relative effect of variation of the fine-structure constant in microwave transitions between very close and narrow rotational-hyperfine levels may be enhanced 2-3 orders of magnitude in diatomic molecules with unpaired electrons like LaS, LaO, LuS, LuO, YbF, and similar molecular ions. The enhancement is result of cancellation between the hyperfine and rotational intervals.

  15. The Effects of Heat Treatment and Microstructure Variations on Disk Superalloy Properties at High Temperature

    NASA Technical Reports Server (NTRS)

    Gabb, Timothy P.; Gayda, John; Telesman, Jack; Garg, Anita

    2008-01-01

    The effects of heat treatment and resulting microstructure variations on high temperature mechanical properties were assessed for a powder metallurgy disk superalloy LSHR. Blanks were consistently supersolvus solution heat treated and quenched at two cooling rates, than aged at varying temperatures and times. Tensile, creep, and dwell fatigue crack growth tests were then performed at 704 C. Gamma' precipitate microstructures were quantified. Relationships between heat treatment-microstructure, heat treatment-mechanical properties, and microstructure-mechanical properties were assessed.

  16. Study on heteroplasmic variation and the effect of chicken mitochondrial ND2.

    PubMed

    Lu, Wei-Wei; Hou, Ling-Ling; Zhang, Wen-Wen; Zhang, Peng-Fei; Chen, Wen; Kang, Xiangtao; Huang, Yanqun

    2016-07-01

    NADH dehydrogenase subunit 2 gene (ND2) is one of the mitochondrial DNA (mtDNA) protein coding genes, which is a subunit of NADH dehydrogenase. The main purpose of this study was to investigate the variation/heteroplasmic sites of chicken ND2, and thus to evaluate the association with chicken growth traits, carcass traits, and serum biochemical indexes. Seventeen variants were detected in the ND2 gene by Sanger sequencing, which constructed 15 haplotypes; the haplotype diversity (hd) was 0.7692. Mt.A5703T and mt.T5727G in the ND2 gene had been detected as the heteroplasmic sites via the created restriction site restriction fragment length polymorphism (CRS-PCR-RFLP) method. Moreover, the study on distribution of two heteroplasmic variants in the Gushi chicken F2 resource population revealed that the heteroplasmic ratio of mt.A5703T and mt.T5727G was 9% and 40%, respectively. It showed that there was obvious heteroplasmic difference between two sites. Association analysis of the variation/heteroplasmy with the related traits in Gushi chicken F2 population showed that the mt.A5703T and mt.T5727G were significantly associated with the pectoral muscle fat content and the duodenum length, but no significance was found with body weight (BW). It was the first time to indicate that heteroplasmic variation had significant effect on growth traits, carcass parameters, and meat quality traits, which showed the potential importance of related variation. PMID:25319280

  17. Modeling variation in early life mortality in the western lowland gorilla: Genetic, maternal and other effects.

    PubMed

    Ahsan, Monica H; Blomquist, Gregory E

    2015-06-01

    Uncovering sources of variation in gorilla infant mortality informs conservation and life history research efforts. The international studbook for the western lowland gorilla provides information on a sample of captive gorillas large enough for which to analyze genetic, maternal, and various other effects on early life mortality in this critically endangered species. We assess the importance of variables such as sex, maternal parity, paternal age, and hand rearing with regard to infant survival. We also quantify the proportions of variation in mortality influenced by heritable variation and maternal effects from these pedigree and survival data using variance component estimation. Markov chain Monte Carlo simulations of generalized linear mixed models produce variance component distributions in an animal model framework that employs all pedigree information. Two models, one with a maternal identity component and one with both additive genetic and maternal identity components, estimate variance components for different age classes during the first 2 years of life. This is informative of the extent to which mortality risk factors change over time during gorilla infancy. Our results indicate that gorilla mortality is moderately heritable with the strongest genetic influence just after birth. Maternal effects are most important during the first 6 months of life. Interestingly, hand-reared infants have lower mortality for the first 6 months of life. Aside from hand rearing, we found other predictors commonly used in studies of primate infant mortality to have little influence in these gorilla data. PMID:25809396

  18. Donor-variation effect on red blood cell storage lesion: A close relationship emerges.

    PubMed

    Tzounakas, Vassilis L; Kriebardis, Anastasios G; Papassideri, Issidora S; Antonelou, Marianna H

    2016-08-01

    Although the molecular pathways leading to the progressive deterioration of stored red blood cells (RBC storage lesion) and the clinical relevance of storage-induced changes remain uncertain, substantial donor-specific variability in RBC performance during storage, and posttransfusion has been established ("donor-variation effect"). In-bag hemolysis and numerous properties of the RBC units that may affect transfusion efficacy have proved to be strongly donor-specific. Donor-variation effect may lead to the production of highly unequal blood labile products even when similar storage strategy and duration are applied. Genetic, undiagnosed/subclinical medical conditions and lifestyle factors that affect RBC characteristics at baseline, including RBC lifespan, energy metabolism, and sensitivity to oxidative stress, are all likely to influence the storage capacity of individual donors' cells, although not evident by the donor's health or hematological status at blood donation. Consequently, baseline characteristics of the donors, such as membrane peroxiredoxin-2 and serum uric acid concentration, have been proposed as candidate biomarkers of storage quality. This review article focuses on specific factors that might contribute to the donor-variation effect and emphasizes the emerging need for using omics-based technologies in association with in vitro and in vivo transfusion models and clinical trials to discover biomarkers of storage quality and posttransfusion recovery in donor blood. PMID:27095294

  19. Anatomic Variant of Liver, Gall Bladder and Inferior Vena Cava

    PubMed Central

    Gladwin, V.; Chand, Parkash

    2016-01-01

    The morphology and relations of liver, gall bladder and inferior vena cava are cardinal. Their anatomical variations may be a reason for the adverse surgical outcome. During routine anatomy dissection of an abdomen, we noticed a variant liver, gall bladder and inferior vena cava in a 63-year-old male cadaver. In the specimen, a retrohepatic segment of inferior vena cava was found to be intrahepatic. On dissection, it was observed that inferior vena cava was covered entirely by a liver tissue on its dorsal aspect. In the same specimen, the gall bladder had undulated inferior surface. On dissection of the gall bladder, numerous mucosal folds were present in the interior. A band of fibrous tissue was found, which was extending from the right side of the gall bladder to the falciform ligament. Hence, preoperative scanning of congenital variations of the liver, gall bladder and inferior vena cava may be compassionate in planning safe surgeries and interventional abdominal procedures.

  20. Multi-allelic major effect genes interact with minor effect QTLs to control adaptive color pattern variation in Heliconius erato.

    PubMed

    Papa, Riccardo; Kapan, Durrell D; Counterman, Brian A; Maldonado, Karla; Lindstrom, Daniel P; Reed, Robert D; Nijhout, H Frederik; Hrbek, Tomas; McMillan, W Owen

    2013-01-01

    Recent studies indicate that relatively few genomic regions are repeatedly involved in the evolution of Heliconius butterfly wing patterns. Although this work demonstrates a number of cases where homologous loci underlie both convergent and divergent wing pattern change among different Heliconius species, it is still unclear exactly how many loci underlie pattern variation across the genus. To address this question for Heliconius erato, we created fifteen independent crosses utilizing the four most distinct color pattern races and analyzed color pattern segregation across a total of 1271 F2 and backcross offspring. Additionally, we used the most variable brood, an F2 cross between H. himera and the east Ecuadorian H. erato notabilis, to perform a quantitative genetic analysis of color pattern variation and produce a detailed map of the loci likely involved in the H. erato color pattern radiation. Using AFLP and gene based markers, we show that fewer major genes than previously envisioned control the color pattern variation in H. erato. We describe for the first time the genetic architecture of H. erato wing color pattern by assessing quantitative variation in addition to traditional linkage mapping. In particular, our data suggest three genomic intervals modulate the bulk of the observed variation in color. Furthermore, we also identify several modifier loci of moderate effect size that contribute to the quantitative wing pattern variation. Our results are consistent with the two-step model for the evolution of mimetic wing patterns in Heliconius and support a growing body of empirical data demonstrating the importance of major effect loci in adaptive change. PMID:23533571

  1. Variation in sensitivity of aquatic species to toxicants: Practical consequences for effect assessment of chemical substances

    SciTech Connect

    Vaal, M.A.; Van Leeuwen, C.J.; Hoekstra, J.A.; Hermens, J.L.M.

    2000-04-01

    This study addresses the relation between the sensitivity of aquatic species and mode of action of different classes or organic chemicals. The authors analyzed large data sets of ecotoxicological information to reveal the interspecies variation in sensitivity, to relate this variation to the compounds' mode of action, and to explain the observed patterns using general biological information. Here the authors present a general framework and recommendations for risk assessment procedures. The authors recommend the use of toxicologically based classification schemes at an early stage of the risk assessment procedure. Screening programs are most efficiently run when only one species per compound is tested to prioritize substances. The toxicity of compounds belonging to the class of nonpolar narcotics is highly predictable and shows little interspecies variation. For these compounds quantitative structure-activity relationships (WSARs) can be used to estimate effect levels. Most effort should be put into testing reactive compounds and compounds with a specific mode of action as toxicity to some species can be 10{sup 5}--10{sup 6} times higher compared with less sensitive species. The use of assessment factors in effect assessment procedures may lead to an underestimation of effects on the more sensitive species. For many priority pollutants there is little information on their ecotoxicity. Predictive techniques are needed to compensate for this lack of data. Knowledge of the relation between modes of action of compounds and interspecies variation in sensitivity should be integrated in risk assessment procedures in order to make more efficient use of the limited financial resources available.

  2. A Need for Logical and Consistent Anatomical Nomenclature for Cutaneous Nerves of the Limbs

    ERIC Educational Resources Information Center

    Gest, Thomas R.; Burkel, William E.; Cortright, Gerald W.

    2009-01-01

    The system of anatomical nomenclature needs to be logical and consistent. However, variations in translation to English of the Latin and Greek terminology used in Nomina Anatomica and Terminologia Anatomica have led to some inconsistency in the nomenclature of cutaneous nerves in the limbs. An historical review of cutaneous nerve nomenclature…

  3. The effect of latitude on the risk and seasonal variation in hip fracture in Sweden.

    PubMed

    Odén, Anders; Kanis, John A; McCloskey, Eugene V; Johansson, Helena

    2014-10-01

    Although the optimal requirement of vitamin D for skeletal health in the general community is controversial, vitamin D deficiency impairs bone mineralization and increases bone turnover via secondary hyperparathyroidism, thus accelerating bone loss and increasing fracture risk. Support for a role of vitamin D deficiency in the epidemiology of hip fracture is found in the seasonal variation of hip fracture incidence that is reported in several studies. If the association were causal, then the incidence and amplitude of the seasonal variation in hip fracture risk should vary by latitude. We addressed this hypothesis by examining the incidence of hip fracture in men and women aged 50 years or more from Sweden (latitudes 55 to 69°) between 1987 and 2009. In order to reduce double counting, only one fracture in a period of a year was counted per individual. Men contributed 104,888 fractures in 33,313,065 person years and women 264,362 fractures in 38,387,660 person years. The effects of season and latitude were examined by Poisson regression. As expected, hip fracture rates were higher in women than in men. After adjustment for age, season and population density, hip fracture incidence increased by 3.0% (95% CI: 2.7-3.2%) per degree increase in latitude for men and by 1.9% (95% CI: 1.8-2.1%) for women. There was a marked seasonal variation of hip fracture with the highest risk in February and lower by 37.5% in men and by 23.5% women during the summer. There were significant interactions of amplitude of the seasonal variation with latitude (p < 0.001 for both men and women), indicating that seasonal variation during the year was more pronounced in the north of Sweden than in the south. The associations found with latitude and season is consistent with a role of vitamin D in hip fracture causation. PMID:24715585

  4. Maternal effects and maternal selection arising from variation in allocation of free amino acid to eggs

    PubMed Central

    Newcombe, Devi; Hunt, John; Mitchell, Christopher; Moore, Allen J

    2015-01-01

    Maternal provisioning can have profound effects on offspring phenotypes, or maternal effects, especially early in life. One ubiquitous form of provisioning is in the makeup of egg. However, only a few studies examine the role of specific egg constituents in maternal effects, especially as they relate to maternal selection (a standardized selection gradient reflecting the covariance between maternal traits and offspring fitness). Here, we report on the evolutionary consequences of differences in maternal acquisition and allocation of amino acids to eggs. We manipulated acquisition by varying maternal diet (milkweed or sunflower) in the large milkweed bug, Oncopeltus fasciatus. Variation in allocation was detected by examining two source populations with different evolutionary histories and life-history response to sunflower as food. We measured amino acids composition in eggs in this 2 × 2 design and found significant effects of source population and maternal diet on egg and nymph mass and of source population, maternal diet, and their interaction on amino acid composition of eggs. We measured significant linear and quadratic maternal selection on offspring mass associated with variation in amino acid allocation. Visualizing the performance surface along the major axes of nonlinear selection and plotting the mean amino acid profile of eggs from each treatment onto the surface revealed a saddle-shaped fitness surface. While maternal selection appears to have influenced how females allocate amino acids, this maternal effect did not evolve equally in the two populations. Furthermore, none of the population means coincided with peak performance. Thus, we found that the composition of free amino acids in eggs was due to variation in both acquisition and allocation, which had significant fitness effects and created selection. However, although there can be an evolutionary response to novel food resources, females may be constrained from reaching phenotypic optima with

  5. Maternal effects and maternal selection arising from variation in allocation of free amino acid to eggs.

    PubMed

    Newcombe, Devi; Hunt, John; Mitchell, Christopher; Moore, Allen J

    2015-06-01

    Maternal provisioning can have profound effects on offspring phenotypes, or maternal effects, especially early in life. One ubiquitous form of provisioning is in the makeup of egg. However, only a few studies examine the role of specific egg constituents in maternal effects, especially as they relate to maternal selection (a standardized selection gradient reflecting the covariance between maternal traits and offspring fitness). Here, we report on the evolutionary consequences of differences in maternal acquisition and allocation of amino acids to eggs. We manipulated acquisition by varying maternal diet (milkweed or sunflower) in the large milkweed bug, Oncopeltus fasciatus. Variation in allocation was detected by examining two source populations with different evolutionary histories and life-history response to sunflower as food. We measured amino acids composition in eggs in this 2 × 2 design and found significant effects of source population and maternal diet on egg and nymph mass and of source population, maternal diet, and their interaction on amino acid composition of eggs. We measured significant linear and quadratic maternal selection on offspring mass associated with variation in amino acid allocation. Visualizing the performance surface along the major axes of nonlinear selection and plotting the mean amino acid profile of eggs from each treatment onto the surface revealed a saddle-shaped fitness surface. While maternal selection appears to have influenced how females allocate amino acids, this maternal effect did not evolve equally in the two populations. Furthermore, none of the population means coincided with peak performance. Thus, we found that the composition of free amino acids in eggs was due to variation in both acquisition and allocation, which had significant fitness effects and created selection. However, although there can be an evolutionary response to novel food resources, females may be constrained from reaching phenotypic optima with

  6. Strong links between genomic and anatomical diversity in both mammalian olfactory chemosensory systems.

    PubMed

    Garrett, Eva C; Steiper, Michael E

    2014-05-22

    Mammalian olfaction comprises two chemosensory systems: the odorant-detecting main olfactory system (MOS) and the pheromone-detecting vomeronasal system (VNS). Mammals are diverse in their anatomical and genomic emphases on olfactory chemosensation, including the loss or reduction of these systems in some orders. Despite qualitative evidence linking the genomic evolution of the olfactory systems to specific functions and phenotypes, little work has quantitatively tested whether the genomic aspects of the mammalian olfactory chemosensory systems are correlated to anatomical diversity. We show that the genomic and anatomical variation in these systems is tightly linked in both the VNS and the MOS, though the signature of selection is different in each system. Specifically, the MOS appears to vary based on absolute organ and gene family size while the VNS appears to vary according to the relative proportion of functional genes and relative anatomical size and complexity. Furthermore, there is little evidence that these two systems are evolving in a linked fashion. The relationships between genomic and anatomical diversity strongly support a role for natural selection in shaping both the anatomical and genomic evolution of the olfactory chemosensory systems in mammals. PMID:24718758

  7. Effects of horizontal velocity variations on ultrasonic velocity measurements in open channels

    USGS Publications Warehouse

    Swain, E.D.

    1992-01-01

    Use of an ultrasonic velocity meter to determine discharge in open channels involves measuring the velocity in a line between transducers in the stream and relating that velocity to the average velocity in the stream. The standard method of calculating average velocity in the channel assumes that the velocity profile in the channel can be represented by the one-dimensional von Karman universal velocity profile. However, the velocity profile can be described by a two-dimensional equation that accounts for the horizontal velocity variations induced by the channel sides. An equation to calculate average velocity accounts for the two-dimensional variations in velocity within a stream. The use of this new equation to calculate average velocity was compared to the standard method in theoretical trapezoidal cross sections and in the L-31N and Snapper Creek Extension Canals near Miami, Florida. These comparisons indicate that the two-dimensional variations have the most significant effect in narrow, deep channels. Also, the two-dimensional effects may be significant in some field situations and need to be considered when determining average velocity and discharge with an ultrasonic velocity meter.

  8. Single Transducer Ultrasonic Imaging Method that Eliminates the Effect of Plate Thickness Variation in the Image

    NASA Technical Reports Server (NTRS)

    Roth, Don J.

    1996-01-01

    This article describes a single transducer ultrasonic imaging method that eliminates the effect of plate thickness variation in the image. The method thus isolates ultrasonic variations due to material microstructure. The use of this method can result in significant cost savings because the ultrasonic image can be interpreted correctly without the need for machining to achieve precise thickness uniformity during nondestructive evaluations of material development. The method is based on measurement of ultrasonic velocity. Images obtained using the thickness-independent methodology are compared with conventional velocity and c-scan echo peak amplitude images for monolithic ceramic (silicon nitride), metal matrix composite and polymer matrix composite materials. It was found that the thickness-independent ultrasonic images reveal and quantify correctly areas of global microstructural (pore and fiber volume fraction) variation due to the elimination of thickness effects. The thickness-independent ultrasonic imaging method described in this article is currently being commercialized under a cooperative agreement between NASA Lewis Research Center and Sonix, Inc.

  9. Stochastic and compensatory effects limit persistence of variation in body mass of young caribou

    USGS Publications Warehouse

    Dale, B.W.; Adams, L.G.; Collins, W.B.; Joly, Kyle; Valkenburg, P.; Tobey, R.

    2008-01-01

    Nutritional restriction during growth can have short- and long-term effects on fitness; however, animals inhabiting uncertain environments may exhibit adaptations to cope with variation in food availability. We examined changes in body mass in free-ranging female caribou (Rangifer tarandus) by measuring mass at birth and at 4, 11, and 16 months of age to evaluate the relative importance of seasonal nutrition to growth, the persistence of cohort-specific variation in body mass through time, and compensatory growth of individuals. Relative mean body mass of cohorts did not persist through time. Compensatory growth of smaller individuals was not observed in summer; however, small calves exhibited more positive change in body mass than did large calves. Compensation occurred during periods of nutritional restriction (winter) rather than during periods of rapid growth (summer) thus differing from the conventional view of compensatory growth. ?? 2008 American Society of Mammalogists.

  10. Electronic correlation effects in a fullerene molecule studied by the variational Monte Carlo method

    SciTech Connect

    Krivnov, V.Y. ); Shamovsky, I.L. Chemistry Department, University of West Indies Mona Campus, St. Andrew, Kingston 7 ); Tornau, E.E. ); Rosengren, A. )

    1994-10-15

    Electron-correlation effects in the fullerene molecule and its ions are investigated in the framework of the Hubbard model. The variational Monte Carlo method and the Gutzwiller wave function are used. Most attention is paid to the case of intermediate interactions, but also the strong coupling limit, where the Hubbard model reduces to the antiferromagnetic Heisenberg model, is considered for the fullerene molecule. In this case we obtain a very low variational ground state energy. Futher, we have calculated the main spin correlation functions in the ground state. Only short-range order is found. The pairing energy of two electrons added to a fullerene molecule or to a fullerene ion is also calculated. Contrary to the results obtained by second-order perturbation theory, pair binding is not found.

  11. Intermodel variations in projected precipitation change over the North Atlantic: Sea surface temperature effect

    NASA Astrophysics Data System (ADS)

    Long, Shang-Min; Xie, Shang-Ping

    2015-05-01

    Intermodel variations in future precipitation projection in the North Atlantic are studied using 23 state-of-art models from Phase 5 of the Coupled Model Intercomparison Project. Model uncertainty in annual mean rainfall change is locally enhanced along the Gulf Stream. The moisture budget analysis reveals that much of the model uncertainty in rainfall change can be traced back to the discrepancies in surface evaporation change and transient eddy effect among models. Results of the intermodel Singular Value Decomposition (SVD) analysis show that intermodel variations in local sea surface temperature (SST) pattern exert a strong control over the spread of rainfall projection among models through the modulation of evaporation change. The first three SVD modes explain more than 60% of the intermodel variance of rainfall projection and show distinct SST patterns with mode water-induced banded structures, reduced subpolar warming due to ocean dynamical cooling, and the Gulf Stream shift, respectively.

  12. Effect of current variation on the dynamics of railgun plasma armatures

    NASA Astrophysics Data System (ADS)

    Rolader, Glenn E.; Batteh, Jad H.; Powell, John D.

    1992-10-01

    The effect of current variations on the behavior of railgun plasma armatures is investigated with a one-dimensional, time-dependent model. Three typical current profiles are considered: two inductive profiles, one with a time constant of 0.5 msec and the other with a time constant of 2.0 msec, and a capacitive profile. All three calculations are for an armature in a 5 cm square-bore railgun. It is observed that current variations create oscillations in the armature length, projectile acceleration, and projectile jerk. In addition, the current profile significantly affects the axial distribution of the plasma velocity, current density, and total pressure. The significance of these transients on the design of projectiles and the interpretation of diagnostic data is discussed, and suggestions for future calculations are outlined.

  13. Earthquake effects in thermal neutron variations at the high-altitude station of Northern

    NASA Astrophysics Data System (ADS)

    Antonova, Valentina; Chubenko, Alexandr; Kryukov, Sergey; Lutsenko, Vadim

    2016-04-01

    Results of study of thermal neutron variations under various space and geophysical conditions on the basis of measurements on stationary installations with high statistical accuracy are presented. Installations are located close to the fault of the earth's crust at the high-altitude station of cosmic rays (3340 m above sea level, 43.02 N, 76.56 E, 20 km from Almaty) in the mountains of Northern Tien-Shan. Responses of the most effective gelio- and geophysical events (variations of atmospheric pressure, coronal mass ejections, earthquakes) has consistently considered in the variations of the thermal neutron flux and compared with variations of high-energy neutrons (standard monitor 18NM64) of galactic origin during these periods. Coefficients of correlation were calculated between data of thermal neutron detectors and data of the neutron monitor, recording the intensity of high-energy particles. High correlation coefficients and similarity of responses to changes of space and geophysical conditions are obtained, that confirms the conclusion of the genetic connection of thermal neutrons with high-energy neutrons of galactic origin and suggests same sources of disturbances in the absence of seismic activity. Observations and analysis of experimental data during the activation of seismic activity in the vicinity of Almaty showed the frequent breakdown of the correlation between the intensity of thermal and high-energy neutrons and the absence of similarity between variations during these periods. We suppose that the additional thermal neutron flux of the lithospheric origin appears under these conditions. Method of separating of thermal neutron flux variations of the lithospheric origin from neutrons variations generated in the atmosphere by subtracting the normalized data is proposed, taking into account the conclusion that variations caused with the atmospheric and interplanetary origins in thermal neutron detectors are similar to variations of high-energy neutrons

  14. Using 3D modeling techniques to enhance teaching of difficult anatomical concepts

    PubMed Central

    Pujol, Sonia; Baldwin, Michael; Nassiri, Joshua; Kikinis, Ron; Shaffer, Kitt

    2016-01-01

    Rationale and Objectives Anatomy is an essential component of medical education as it is critical for the accurate diagnosis in organs and human systems. The mental representation of the shape and organization of different anatomical structures is a crucial step in the learning process. The purpose of this pilot study is to demonstrate the feasibility and benefits of developing innovative teaching modules for anatomy education of first-year medical students based on 3D reconstructions from actual patient data. Materials and Methods A total of 196 models of anatomical structures from 16 anonymized CT datasets were generated using the 3D Slicer open-source software platform. The models focused on three anatomical areas: the mediastinum, the upper abdomen and the pelvis. Online optional quizzes were offered to first-year medical students to assess their comprehension in the areas of interest. Specific tasks were designed for students to complete using the 3D models. Results Scores of the quizzes confirmed a lack of understanding of 3D spatial relationships of anatomical structures despite standard instruction including dissection. Written task material and qualitative review by students suggested that interaction with 3D models led to a better understanding of the shape and spatial relationships among structures, and helped illustrate anatomical variations from one body to another. Conclusion The study demonstrates the feasibility of one possible approach to the generation of 3D models of the anatomy from actual patient data. The educational materials developed have the potential to supplement the teaching of complex anatomical regions and help demonstrate the anatomic variation among patients. PMID:26897601

  15. Population Genetic Variation in the Tree Fern Alsophila spinulosa (Cyatheaceae): Effects of Reproductive Strategy

    PubMed Central

    Wang, Ting; Su, Yingjuan; Li, Yuan

    2012-01-01

    Background Essentially all ferns can perform both sexual and asexual reproduction. Their populations represent suitable study objects to test the population genetic effects of different reproductive systems. Using the diploid homosporous fern Alsophila spinulosa as an example species, the main purpose of this study was to assess the relative impact of sexual and asexual reproduction on the level and structure of population genetic variation. Methodology/Principal Findings Inter-simple sequence repeats analysis was conducted on 140 individuals collected from seven populations (HSG, LCH, BPC, MPG, GX, LD, and ZHG) in China. Seventy-four polymorphic bands discriminated a total of 127 multilocus genotypes. Character compatibility analysis revealed that 50.0 to 70.0% of the genotypes had to be deleted in order to obtain a tree-like structure in the data set from populations HSG, LCH, MPG, BPC, GX, and LD; and there was a gradual decrease of conflict in the data set when genotypes with the highest incompatibility counts were successively deleted. In contrast, in population ZHG, only 33.3% of genotypes had to be removed to achieve complete compatibility in the data set, which showed a sharp decline in incompatibility upon the deletion of those genotypes. All populations examined possessed similar levels of genetic variation. Population ZHG was not found to be more differentiated than the other populations. Conclusions/Significance Sexual recombination is the predominant source of genetic variation in most of the examined populations of A. spinulosa. However, somatic mutation contributes most to the genetic variation in population ZHG. This change of the primary mode of reproduction does not cause a significant difference in the population genetic composition. Character compatibility analysis represents an effective approach to separate the role of sexual and asexual components in shaping the genetic pattern of fern populations. PMID:22911855

  16. Effect of Variation in Test Methods on Performance of Ultraviolet-C Radiation Room Decontamination.

    PubMed

    Cadnum, Jennifer L; Tomas, Myreen E; Sankar, Thriveen; Jencson, Annette; Mathew, J Itty; Kundrapu, Sirisha; Donskey, Curtis J

    2016-05-01

    OBJECTIVE To determine the effect of variation in test methods on performance of an ultraviolet-C (UV-C) room decontamination device. DESIGN Laboratory evaluation. METHODS We compared the efficacy of 2 UV-C room decontamination devices with low pressure mercury gas bulbs. For 1 of the devices, we evaluated the effect of variation in spreading of the inoculum, carrier orientation relative to the device, type of organic load, type of carrier, height of carrier, and uninterrupted versus interrupted exposures on measured UV-C killing of methicillin-resistant Staphylococcus aureus and Clostridium difficile spores. RESULTS The 2 UV-C room decontamination devices achieved similar log10 colony-forming unit reductions in the pathogens with exposure times ranging from 5 to 40 minutes. On steel carriers, spreading of the inoculum over a larger surface area significantly enhanced killing of both pathogens, such that a 10-minute exposure on a 22-mm2 disk resulted in greater than 2 log reduction in C. difficile spores. Orientation of carriers in parallel rather than perpendicular with the UV-C lamps significantly enhanced killing of both pathogens. Different types of organic load also significantly affected measured organism reductions, whereas type of carrier, variation in carrier height, and interrupted exposure cycles did not. CONCLUSIONS Variation in test methods can significantly impact measured reductions in pathogens by UV-C devices during experimental testing. Our findings highlight the need for standardized laboratory methods for testing the efficacy of UV-C devices and for evaluations of the efficacy of short UV-C exposure times in real-world settings. Infect Control Hosp Epidemiol 2016;37:555-560. PMID:26809607

  17. Late Pleistocene climate change and the global expansion of anatomically modern humans

    PubMed Central

    Eriksson, Anders; Betti, Lia; Friend, Andrew D.; Lycett, Stephen J.; Singarayer, Joy S.; von Cramon-Taubadel, Noreen; Valdes, Paul J.; Balloux, Francois; Manica, Andrea

    2012-01-01

    The extent to which past climate change has dictated the pattern and timing of the out-of-Africa expansion by anatomically modern humans is currently unclear [Stewart JR, Stringer CB (2012) Science 335:1317–1321]. In particular, the incompleteness of the fossil record makes it difficult to quantify the effect of climate. Here, we take a different approach to this problem; rather than relying on the appearance of fossils or archaeological evidence to determine arrival times in different parts of the world, we use patterns of genetic variation in modern human populations to determine the plausibility of past demographic parameters. We develop a spatially explicit model of the expansion of anatomically modern humans and use climate reconstructions over the past 120 ky based on the Hadley Centre global climate model HadCM3 to quantify the possible effects of climate on human demography. The combinations of demographic parameters compatible with the current genetic makeup of worldwide populations indicate a clear effect of climate on past population densities. Our estimates of this effect, based on population genetics, capture the observed relationship between current climate and population density in modern hunter–gatherers worldwide, providing supporting evidence for the realism of our approach. Furthermore, although we did not use any archaeological and anthropological data to inform the model, the arrival times in different continents predicted by our model are also broadly consistent with the fossil and archaeological records. Our framework provides the most accurate spatiotemporal reconstruction of human demographic history available at present and will allow for a greater integration of genetic and archaeological evidence. PMID:22988099

  18. The effect of developmental stage on eggshell thickness variation in endangered falcons.

    PubMed

    Castilla, Aurora M; Herrel, Anthony; Robles, Hugo; Malone, Jim; Negro, Juan José

    2010-05-01

    We compared eggshell thickness of hatched eggs with that of non-developed eggs in endangered falcon taxa to explore the effect of embryo development on eggshell thinning. To our knowledge, this has never been examined before in falcons, despite the fact that eggshell thinning due to pollutants and environmental contamination is often considered the most common cause of egg failure in falcons. Because of the endangered nature of these birds, and the difficulty in gaining access to the nests and their eggs, there is a large gap in our knowledge regarding eggshell thickness variation and the factors affecting it. We used a linear mixed-effects (LME) model to explore the variation in eggshell thickness (n=335 eggs) in relation to the developmental stage of the eggs, but also in relation to the falcon taxa, the laying sequence and the study zone. Female identity (n=69) and clutch identity (n=98) were also included in the LME model. Our results are consistent with the prediction that eggshell thickness decreases during incubation because of the important effect of calcium uptake by the embryo during development. Our results also show that eggs laid later in the sequence had significantly thinner eggshells. In this study, we provide the first quantitative data on eggshell thickness variation of hatched eggs in different falcon taxa that were not subjected to contamination or food limitation (i.e., bred under captive conditions). Because eggshell thickness strongly influences survival and because the species examined in this study are endangered, our data represent a valuable control for future studies on the effects of pollution on eggshells from wild populations and thus are an important contribution to the conservation of falcons. PMID:20435452

  19. The contextual interference effect for skill variations from the same and different generalized motor programs.

    PubMed

    Sekiya, H; Magill, R A; Sidaway, B; Anderson, D I

    1994-12-01

    Magill and Hall (1990) hypothesized that the contextual interference (CI) effect is found only when task variations to be learned are governed by different generalized motor programs (GMPs). The present experiments examined their hypothesis by requiring subjects to learn variations of a tapping task that had either different (Experiment 1) or the same (Experiment 2) relative timing structure. In each experiment, subjects (N = 36) performed 270 acquisition trials with knowledge of results (KR) in either a blocked or a serial order. One day later, subjects performed 30 retention trials without KR. In data analyses, errors due to parameter modifications were dissociated from errors due to GMP construction to examine which process was responsible for the CI effect. In both experiments, parameter learning created a CI effect while GMP learning failed to produce a CI effect. In the light of these findings, a modification is proposed to the Magill and Hall (1990) hypothesis that takes into account these distinct processes in motor learning. PMID:7886282

  20. Effect of Helical Slow-Wave Circuit Variations on TWT Cold-Test Characteristics

    NASA Technical Reports Server (NTRS)

    Kory, Carol L.; Dayton, James A., Jr.

    1998-01-01

    Recent advances in the state of the art of computer modeling offer the possibility for the first time to evaluate the effect that slow-wave structure parameter variations, such'as manufacturing tolerances, have on the cold-test characteristics of helical traveling-wave tubes (TWT's). This will enable manufacturers to determine the cost effectiveness of controlling the dimensions of the component parts of the TWT, which is almost impossible to do experimentally without building a large number of tubes and controlling several parameters simultaneously. The computer code MAxwell's equations by the Finite Integration Algorithm (MAFIA) is used in this analysis to determine the effect on dispersion and on-axis interaction impedance of several helical slow-wave circuit parameter variations, including thickness and relative dielectric constant of the support rods, tape width, and height of the metallized films deposited on the dielectric rods. Previous computer analyzes required so many approximations that accurate determinations of the effect of many relevant dimensions on tube performance were practically impossible.

  1. Analysis of anatomic variability in children with low mathematical skills

    NASA Astrophysics Data System (ADS)

    Han, Zhaoying; Fuchs, Lynn; Davis, Nikki; Cannistraci, Christopher J.; Anderson, Adam W.; Gore, John C.; Dawant, Benoit M.

    2008-03-01

    Mathematical difficulty affects approximately 5-9% of the population. Studies on individuals with dyscalculia, a neurologically based math disorder, provide important insight into the neural correlates of mathematical ability. For example, cognitive theories, neuropsychological studies, and functional neuroimaging studies in individuals with dyscalculia suggest that the bilateral parietal lobes and intraparietal sulcus are central to mathematical performance. The purpose of the present study was to investigate morphological differences in a group of third grade children with poor math skills. We compare population averages of children with low math skill (MD) to gender and age matched controls with average math ability. Anatomical data were gathered with high resolution MRI and four different population averaging methods were used to study the effect of the normalization technique on the results. Statistical results based on the deformation fields between the two groups show anatomical differences in the bilateral parietal lobes, right frontal lobe, and left occipital/parietal lobe.

  2. Anatomic femorotibial changes associated with tibial plateau leveling osteotomy

    PubMed Central

    Schultz, Jennifer A.; Allen, David A.; Bergman, Philip J.

    2015-01-01

    This prospective study evaluated anatomic femorotibial changes utilizing the relationship between the intercondylar notch and the intercondylar eminence following tibial plateau leveling osteotomy (TPLO). We hypothesized that TPLO results in anatomic alteration of the femorotibial joint. Pre- and post-operative computed tomography (CT) scans of cranial cruciate deficient stifle joints treated with TPLO were performed on 25 client-owned dogs. Computed tomography scans were performed at 3 different stifle angles: extension, 135° walking angle, and 90° of flexion. Tibial plateau leveling osteotomy did not result in a significant medial or lateral shift of the intercondylar eminence relative to the intercondylar notch. There was a significant cranial shift of the intercondylar eminence with the stifle in extension following TPLO. In addition, TPLO resulted in a significantly narrowed femorotibial joint space. The biomechanical effects of TPLO and medial meniscal release need to be further defined. PMID:26345618

  3. Anatomic femorotibial changes associated with tibial plateau leveling osteotomy.

    PubMed

    Schultz, Jennifer A; Allen, David A; Bergman, Philip J

    2015-09-01

    This prospective study evaluated anatomic femorotibial changes utilizing the relationship between the intercondylar notch and the intercondylar eminence following tibial plateau leveling osteotomy (TPLO). We hypothesized that TPLO results in anatomic alteration of the femorotibial joint. Pre- and post-operative computed tomography (CT) scans of cranial cruciate deficient stifle joints treated with TPLO were performed on 25 client-owned dogs. Computed tomography scans were performed at 3 different stifle angles: extension, 135° walking angle, and 90° of flexion. Tibial plateau leveling osteotomy did not result in a significant medial or lateral shift of the intercondylar eminence relative to the intercondylar notch. There was a significant cranial shift of the intercondylar eminence with the stifle in extension following TPLO. In addition, TPLO resulted in a significantly narrowed femorotibial joint space. The biomechanical effects of TPLO and medial meniscal release need to be further defined. PMID:26345618

  4. Anatomical, functional and molecular biomarker applications of magnetic resonance neuroimaging

    PubMed Central

    Liu, Christina H

    2015-01-01

    MRI and magnetic resonance spectroscopy (MRS) along with computed tomography and PET are the most common imaging modalities used in the clinics to detect structural abnormalities and pathological conditions in the brain. MRI generates superb image resolution/contrast without radiation exposure that is associated with computed tomography and PET; MRS and spectroscopic imaging technologies allow us to measure changes in brain biochemistry. Increasingly, neurobiologists and MRI scientists are collaborating to solve neuroscience problems across sub-cellular through anatomical levels. To achieve successful cross-disciplinary collaborations, neurobiologists must have sufficient knowledge of magnetic resonance principles and applications in order to effectively communicate with their MRI colleagues. This review provides an overview of magnetic resonance techniques and how they can be used to gain insight into the active brain at the anatomical, functional and molecular levels with the goal of encouraging neurobiologists to include MRI/MRS as a research tool in their endeavors. PMID:25774094

  5. The primo vascular system as a new anatomical system.

    PubMed

    Stefanov, Miroslav; Potroz, Michael; Kim, Jungdae; Lim, Jake; Cha, Richard; Nam, Min-Ho

    2013-12-01

    Traditional Eastern medicine has had a successful existence for a long time and has provided functional paths for curing disease. However, some scientists do not accept acupuncture, primarily because the meridian system lacks a physical anatomical basis. To date, scientific theories have not been able to explain the functional paths used by traditional Eastern medicine to cure disease. According to Western medicine, no known anatomical foundation exists for the meridians and unknown nervous, circulatory, endocrine, and immune mechanisms mediate the effects of acupuncture. In the early 1960s, only one hypothesis was proposed to explain the anatomical basis of the meridians. By using different experimental approaches during the past 10 years, the number of scientific papers that report the discovery of different anatomical and physiological evidence confirming the existence of an anatomical basis for the meridian system has increased. Morphological science is greatly challenged to offer a new biomedical theory that explains the possible existence of new bodily systems such as the primo vascular system (PVS). The PVS is a previously unknown system that integrates the features of the cardiovascular, nervous, immune, and hormonal systems. It also provides a physical substrate for the acupuncture points and meridians. Announcements of the morphological architectonics and the function of the PVS fundamentally changed the basic understanding of biology and medicine because the PVS is involved in the development and the functions of living organisms. We propose a new vision of the anatomical basis for the PVS and the vital energy-called "Qi"-as an electromagnetic wave that is involved very closely with the DNA in the PVS. DNA provides genetic information and it functions as a store of information that can be obtained from the electromagnetic fields of the environment. The PVS is the communication system between living organisms and the environment, and it lies at the lowest

  6. Stratospheric effects of solar ultraviolet variations on the solar rotation time scale

    NASA Technical Reports Server (NTRS)

    Hood, L. L.

    1989-01-01

    A summary is presented of some current work on measurement and interpretation of stratospheric ozone and temperature responses to observed short term solar ultraviolet variations. Although some studies have yielded provisional evidence for a nearly in-phase ozone-solar cycle relationship, they extend at most over only one or two 11 year cycles so the statistical significance of the correlations is not large. Similarly, the relatively short lengths of individual satellite data sets combined with the problem of estimating the effect of changes in instrument sensitivity (drift) during the observing period have complicated attempts to infer long term or solar cycle ozone trends. The solar rotation and active region development time scale provides an alternate time scale for which detailed studies of middle atmospheric ozone and temperature responses to solar ultraviolet variability are currently possible using available satellite data sets. At tropical latitudes where planetary wave amplitudes are relatively small, clear correlative evidence for the existence of middle atmospheric ozone and temperature responses to short term solar ultraviolet variations has been obtained in recent years. These measurements will ultimately allow improved empirical and theoretical calculations of longer term solar induced ozone and temperature variations at low and middle latitudes.

  7. Effect of Seasonal Variation of Anomalous Condition on Radio Propagation in Nigeria

    NASA Astrophysics Data System (ADS)

    Emmanuel, Israel; Adeyemi, Babatunde; Ogolo, Emmanuel; Adediji, Adekunle

    Daily variation of effective earth radius factor and seasonal variation of refractivity gradients from surface to around 1000 m above ground level in the tropospheric layer are presented based on observation from the meteorological data obtain from ECMWF database. Thirty four years (1979 -2014) of data from surface and profile of Era Interim of the temperature and relative humidity are used to determine the surface anomalous propagation over some selected location I Nigeria. Estimation of anomalous propagation are observed for onset and peak of rainy and dry seasons. The occurrence of anomalous strongly depends on the local time and synoptic weather conditions which have an appreciable on the refractivity vertical profile, especially the seasonal north - south movement of inter tropical Convergence Zone (ITCD) which provide wet and dry seasonal variations of anomalous were also determined. Spatial distribution of refractivity gradient for both wet and dry seasons are also obtained. The highest occurrence of duct were noticed in the night and morning (00:00 UTC and 06:00UTC) across the country though it was low in the northern part of the country, while low or no occurrence of duct were observed in the afternoon and evening (12:00 UTC and 18:00 UTC). Also percentage occurrence of duct were also high and low during the wet and dry seasons respectively.

  8. Load variation effects on the pressure fluctuations exerted on a Kaplan turbine runner

    NASA Astrophysics Data System (ADS)

    Amiri, K.; Mulu, B.; Raisee, M.; Cervantes, M. J.

    2014-03-01

    Introduction of intermittent electricity production systems like wind power and solar systems to electricity market together with the consumption-based electricity production resulted in numerous start/stops, load variations and off-design operation of water turbines. The hydropower systems suffer from the varying loads exerted on the stationary and rotating parts of the turbines during load variations which they are not designed for. On the other hand, investigations on part load operation of single regulated turbines, i.e., Francis and propeller, proved the formation of rotating vortex rope (RVR) in the draft tube. The RVR induces oscillating flow both in plunging and rotating modes which results in oscillating force with two different frequencies on the runner blades, bearings and other rotating parts of the turbine. The purpose of this study is to investigate the effect of transient operations on the pressure fluctuations on the runner and mechanism of the RVR formation/mitigation. Draft tube and runner blades of the Porjus U9 model, a Kaplan turbine, were equipped with pressure sensors. The model was run in off-cam mode during different load variation conditions to check the runner performance under unsteady condition. The results showed that the transients between the best efficiency point and the high load happens in a smooth way while transitions to/from the part load, where rotating vortex rope (RVR) forms in the draft tube induces high level of fluctuations with two frequencies on the runner; plunging and rotating mode of the RVR.

  9. Collaborative regression-based anatomical landmark detection

    NASA Astrophysics Data System (ADS)

    Gao, Yaozong; Shen, Dinggang

    2015-12-01

    Anatomical landmark detection plays an important role in medical image analysis, e.g. for registration, segmentation and quantitative analysis. Among the various existing methods for landmark detection, regression-based methods have recently attracted much attention due to their robustness and efficiency. In these methods, landmarks are localised through voting from all image voxels, which is completely different from the classification-based methods that use voxel-wise classification to detect landmarks. Despite their robustness, the accuracy of regression-based landmark detection methods is often limited due to (1) the inclusion of uninformative image voxels in the voting procedure, and (2) the lack of effective ways to incorporate inter-landmark spatial dependency into the detection step. In this paper, we propose a collaborative landmark detection framework to address these limitations. The concept of collaboration is reflected in two aspects. (1) Multi-resolution collaboration. A multi-resolution strategy is proposed to hierarchically localise landmarks by gradually excluding uninformative votes from faraway voxels. Moreover, for informative voxels near the landmark, a spherical sampling strategy is also designed at the training stage to improve their prediction accuracy. (2) Inter-landmark collaboration. A confidence-based landmark detection strategy is proposed to improve the detection accuracy of ‘difficult-to-detect’ landmarks by using spatial guidance from ‘easy-to-detect’ landmarks. To evaluate our method, we conducted experiments extensively on three datasets for detecting prostate landmarks and head & neck landmarks in computed tomography images, and also dental landmarks in cone beam computed tomography images. The results show the effectiveness of our collaborative landmark detection framework in improving landmark detection accuracy, compared to other state-of-the-art methods.

  10. Standardized anatomic space for abdominal fat quantification

    NASA Astrophysics Data System (ADS)

    Tong, Yubing; Udupa, Jayaram K.; Torigian, Drew A.

    2014-03-01

    The ability to accurately measure subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) from images is important for improved assessment and management of patients with various conditions such as obesity, diabetes mellitus, obstructive sleep apnea, cardiovascular disease, kidney disease, and degenerative disease. Although imaging and analysis methods to measure the volume of these tissue components have been developed [1, 2], in clinical practice, an estimate of the amount of fat is obtained from just one transverse abdominal CT slice typically acquired at the level of the L4-L5 vertebrae for various reasons including decreased radiation exposure and cost [3-5]. It is generally assumed that such an estimate reliably depicts the burden of fat in the body. This paper sets out to answer two questions related to this issue which have not been addressed in the literature. How does one ensure that the slices used for correlation calculation from different subjects are at the same anatomic location? At what anatomic location do the volumes of SAT and VAT correlate maximally with the corresponding single-slice area measures? To answer these questions, we propose two approaches for slice localization: linear mapping and non-linear mapping which is a novel learning based strategy for mapping slice locations to a standardized anatomic space so that same anatomic slice locations are identified in different subjects. We then study the volume-to-area correlations and determine where they become maximal. We demonstrate on 50 abdominal CT data sets that this mapping achieves significantly improved consistency of anatomic localization compared to current practice. Our results also indicate that maximum correlations are achieved at different anatomic locations for SAT and VAT which are both different from the L4-L5 junction commonly utilized.

  11. Effects of Different Variations of Mental and Physical Practice on Sport Skill Learning in Adolescents with Mental Retardation

    ERIC Educational Resources Information Center

    Hemayattalab, Rasool; Movahedi, Ahmadreza

    2010-01-01

    The purpose of this study was to investigate the effect of five variations of imagery and physical practice on learning of Basketball free throws in adolescents with mental retardation (AWMR). Forty AWMR were randomly assigned to five groups and performed a variation of practice: physical practice, mental practice, physical practice followed by…

  12. Short Term Cognitive Effects of Head Start Programs: A Report on the Third Year of Planned Variation--1971-72.

    ERIC Educational Resources Information Center

    Weisberg, Herbert I.

    This report focuses on three main questions: (1) To what extent does a Head Start experience accelerate the rate at which disadvantaged preschoolers acquire cognitive skills? (2) Are the Planned Variation models, simply by virtue of sponsorship more effective than ordinary nonsponsored Head Start programs? and (3) Are some Planned Variation models…

  13. Genetics in endocrinology: genetic variation in deiodinases: a systematic review of potential clinical effects in humans.

    PubMed

    Verloop, Herman; Dekkers, Olaf M; Peeters, Robin P; Schoones, Jan W; Smit, Johannes W A

    2014-09-01

    Iodothyronine deiodinases represent a family of selenoproteins involved in peripheral and local homeostasis of thyroid hormone action. Deiodinases are expressed in multiple organs and thyroid hormone affects numerous biological systems, thus genetic variation in deiodinases may affect multiple clinical endpoints. Interest in clinical effects of genetic variation in deiodinases has clearly increased. We aimed to provide an overview for the role of deiodinase polymorphisms in human physiology and morbidity. In this systematic review, studies evaluating the relationship between deiodinase polymorphisms and clinical parameters in humans were eligible. No restrictions on publication date were imposed. The following databases were searched up to August 2013: Pubmed, EMBASE (OVID-version), Web of Science, COCHRANE Library, CINAHL (EbscoHOST-version), Academic Search Premier (EbscoHOST-version), and ScienceDirect. Deiodinase physiology at molecular and tissue level is described, and finally the role of these polymorphisms in pathophysiological conditions is reviewed. Deiodinase type 1 (D1) polymorphisms particularly show moderate-to-strong relationships with thyroid hormone parameters, IGF1 production, and risk for depression. D2 variants correlate with thyroid hormone levels, insulin resistance, bipolar mood disorder, psychological well-being, mental retardation, hypertension, and risk for osteoarthritis. D3 polymorphisms showed no relationship with inter-individual variation in serum thyroid hormone parameters. One D3 polymorphism was associated with risk for osteoarthritis. Genetic deiodinase profiles only explain a small proportion of inter-individual variations in serum thyroid hormone levels. Evidence suggests a role of genetic deiodinase variants in certain pathophysiological conditions. The value for determination of deiodinase polymorphism in clinical practice needs further investigation. PMID:24878678

  14. Effects of the observed J2 variations on the Earth's precession and nutation

    NASA Astrophysics Data System (ADS)

    Ferrándiz, José M.; Baenas, Tomás; Belda, Santiago

    2016-04-01

    The Earth's oblateness parameter J2 is closely related to the dynamical ellipticity H, which factorizes the main components of the precession and the different nutation terms. In most theoretical approaches to the Earth's rotation, with IAU2000 nutation theory among them, H is assumed to be constant. The precession model IAU2006 supposes H to have a conventional linear variation, based on the J2 time series derived mainly from satellite laser ranging (SLR) data for decades, which gives rise to an additional quadratic term of the precession in longitude and some corrections of the nutation terms. The time evolution of J2 is, however, too complex to be well approximated by a simple linear model. The effect of more general models including periodic terms and closer to the observed time series, although still unable to reproduce a significant part of the signal, has been seldom investigated. In this work we address the problem of deriving the effect of the observed J2 variations without resorting to such simplified models. The Hamiltonian approach to the Earth rotation is extended to allow the McCullagh's term of the potential to depend on a time-varying oblateness. An analytical solution is derived by means of a suitable perturbation method in the case of the time series provided by the Center for Space Research (CSR) of the University of Texas, which results in non-negligible contributions to the precession-nutation angles. The presentation focuses on the main effects on the longitude of the equator; a noticeable non-linear trend is superimposed to the linear main precession term, along with some periodic and decadal variations.

  15. Anatomic considerations for central venous cannulation

    PubMed Central

    Bannon, Michael P; Heller, Stephanie F; Rivera, Mariela

    2011-01-01

    Central venous cannulation is a commonly performed procedure which facilitates resuscitation, nutritional support, and long-term vascular access. Mechanical complications most often occur during insertion and are intimately related to the anatomic relationship of the central veins. Working knowledge of surface and deep anatomy minimizes complications. Use of surface anatomic landmarks to orient the deep course of cannulating needle tracts appropriately comprises the crux of complication avoidance. The authors describe use of surface landmarks to facilitate safe placement of internal jugular, subclavian, and femoral venous catheters. The role of real-time sonography as a safety-enhancing adjunct is reviewed. PMID:22312225

  16. Anatomical and clinical aspects of Klinefelter's syndrome.

    PubMed

    Bird, Rebecca J; Hurren, Bradley J

    2016-07-01

    Klinefelter's syndrome, the most common sex disorder associated with chromosomal aberrations, is characterized by a plethora of clinical features. Parameters for diagnosis of the syndrome are constantly expanding as new anatomical and hormonal abnormalities are noted, yet Klinefelter's remains underdiagnosed and underreported. This review outlines the key anatomical characteristics associated with the syndrome, which are currently used for clinical diagnosis, or may provide means for improving diagnosis in the future. Clin. Anat. 29:606-619, 2016. © 2016 Wiley Periodicals, Inc. PMID:26823086

  17. Anatomical variants and pathologies of the vermix

    PubMed Central

    Deshmukh, Swati; Verde, Franco; Johnson, Pamela T.; Fishman, Elliot K.

    2015-01-01

    The appendix may demonstrate a perplexing range of normal and abnormal appearances on imaging exams. Familiarity with the anatomy and anatomical variants of the appendix is helpful in identifying the appendix on ultrasound, computed tomography, and magnetic resonance imaging. Knowledge of the variety of pathologies afflicting the appendix and of the spectrum of imaging findings may be particularly useful to the emergency radiologist for accurate diagnosis and appropriate guidance regarding clinical and surgical management. In this pictorial essay, we review appendiceal embryology, anatomical variants such as Amyand hernias, and pathologies from appendicitis to carcinoid, mucinous, and nonmucinous epithelial neoplasms. PMID:24570122

  18. Human cochlea: anatomical characteristics and their relevance for cochlear implantation.

    PubMed

    Rask-Andersen, Helge; Liu, Wei; Erixon, Elsa; Kinnefors, Anders; Pfaller, Kristian; Schrott-Fischer, Annelies; Glueckert, Rudolf

    2012-11-01

    This is a review of the anatomical characteristics of human cochlea and the importance of variations in this anatomy to the process of cochlear implantation (CI). Studies of the human cochlea are essential to better comprehend the physiology and pathology of man's hearing. The human cochlea is difficult to explore due to its vulnerability and bordering capsule. Inner ear tissue undergoes quick autolytic changes making investigations of autopsy material difficult, even though excellent results have been presented over time. Important issues today are novel inner ear therapies including CI and new approaches for inner ear pharmacological treatments. Inner ear surgery is now a reality, and technical advancements in the design of electrode arrays and surgical approaches allow preservation of remaining structure/function in most cases. Surgeons should aim to conserve cochlear structures for future potential stem cell and gene therapies. Renewal interest of round window approaches necessitates further acquaintance of this complex anatomy and its variations. Rough cochleostomy drilling at the intricate "hook" region can generate intracochlear bone-dust-inducing fibrosis and new bone formation, which could negatively influence auditory nerve responses at a later time point. Here, we present macro- and microanatomic investigations of the human cochlea viewing the extensive anatomic variations that influence electrode insertion. In addition, electron microscopic (TEM and SEM) and immunohistochemical results, based on specimens removed at surgeries for life-threatening petroclival meningioma and some well-preserved postmortal tissues, are displayed. These give us new information about structure as well as protein and molecular expression in man. Our aim was not to formulate a complete description of the complex human anatomy but to focus on aspects clinically relevant for electric stimulation, predominantly, the sensory targets, and how surgical atraumaticity best could be

  19. Construction of a 3-D anatomical model for teaching temporal lobectomy.

    PubMed

    de Ribaupierre, Sandrine; Wilson, Timothy D

    2012-06-01

    Although we live and work in 3 dimensional space, most of the anatomical teaching during medical school is done on 2-D (books, TV and computer screens, etc). 3-D spatial abilities are essential for a surgeon but teaching spatial skills in a non-threatening and safe educational environment is a much more difficult pedagogical task. Currently, initial anatomical knowledge formation or specific surgical anatomy techniques, are taught either in the OR itself, or in cadaveric labs; which means that the trainee has only limited exposure. 3-D computer models incorporated into virtual learning environments may provide an intermediate and key step in a blended learning approach for spatially challenging anatomical knowledge formation. Specific anatomical structures and their spatial orientation can be further clinically contextualized through demonstrations of surgical procedures in the 3-D digital environments. Recordings of digital models enable learner reviews, taking as much time as they want, stopping the demonstration, and/or exploring the model to understand the anatomical relation of each structure. We present here how a temporal lobectomy virtual model has been developed to aid residents and fellows conceptualization of the anatomical relationships between different cerebral structures during that procedure. We suggest in comparison to cadaveric dissection, such virtual models represent a cost effective pedagogical methodology providing excellent support for anatomical learning and surgical technique training. PMID:22513297

  20. The effects of ground hydrology on climate sensitivity to solar constant variations

    NASA Technical Reports Server (NTRS)

    Chou, S. H.; Curran, R. J.; Ohring, G.

    1979-01-01

    The effects of two different evaporation parameterizations on the climate sensitivity to solar constant variations are investigated by using a zonally averaged climate model. The model is based on a two-level quasi-geostrophic zonally averaged annual mean model. One of the evaporation parameterizations tested is a nonlinear formulation with the Bowen ratio determined by the predicted vertical temperature and humidity gradients near the earth's surface. The other is the linear formulation with the Bowen ratio essentially determined by the prescribed linear coefficient.

  1. Atmospheric effects and sidereal-diurnal variations in extended air showers

    NASA Technical Reports Server (NTRS)

    Efimov, N. N.; Krasilnikov, D. D.; Nikolskiy, S. N.; Shamsutdinova, F. K.

    1975-01-01

    Observations are presented on the variations of extended air shower intensity with an average power of 1.4 x 10,000 and 1.4 x 100,000 particles at sea level. The effect of disintegrating particles and the essential role of cascades formed above the lower third of the atmosphere are examined. However, the authors failed to discover anisotropy of initial particles with an energy of 10 to the 14th power to 10 to the 15th power eV with an accuracy of up to 0.1%.

  2. The effect of small variations in the magnetization curves of shielding material upon shielded fields

    NASA Astrophysics Data System (ADS)

    Kost, A.; Jacobs, R. T.; Hahn, A.

    2007-08-01

    The shielding of strong electromagnetic fields at power frequency, performed by ferromagnetic plates, is often successfully modelled by the effective reluctivity. This method delivers good results for the RMSvalue of the shielded field. The following paper shows that a small variation of the magnetization curve (e.g.by taking another material charge) can strongly influence the shielded field. The field calculation is performed by the Finite Element Method (FEM), where for the interior plate region a)finite elements and b)non-linear Impedance Boundary Conditions (IBC) are used which circumvents the need to discretize the shielding plate.

  3. The effect of spatial variation in potential energy on the diffusion in heterogeneous media

    NASA Astrophysics Data System (ADS)

    Livshits, A. I.

    2016-05-01

    The standard equation of diffusion in heterogeneous media is found to be incomplete. The effect of heterogeneity on diffusion phenomena is commonly considered to be caused by only spatial variations of diffusion coefficient while the spatial difference in the potential energy of diffusing particles due to their interactions with the inhomogeneous medium is not taken into consideration. The possibility of new transport phenomena in heterogeneous media follows from the corrected equation. In particular the great increase of hydrogen permeability through the membranes of metallic alloy is turned out possible due to an optimization of spatial distribution of the alloy composition.

  4. Effect of growth parameters on compositional variations in directionally solidified HgCdTe alloys

    NASA Technical Reports Server (NTRS)

    Szofran, F. R.; Chandra, D.; Wang, J.-C.; Cothran, E. K.; Lehoczky, S. L.

    1984-01-01

    A series of Hg(1-x)Cd(x)Te alloy crystals was grown by directional solidification with compositions ranging from x = 0.2 to x = 0.4. The measured axial compositional profiles were interpreted in terms of an exact numerical solution of the appropriate diffusion equation that takes into account both the variations of the segregation coefficient and solidification rate with composition. The solutions for all growth rates agree generally well with the experimental data, and confirm earlier observations that employed approximate analytical solutions. The effective mass diffusion coefficients showed no significant composition or melt temperature dependence. Slightly higher diffusion coefficients were obtained, however, for the highest growth rates.

  5. Socioeconomic variation in recall and perceived effectiveness of campaign advertisements to promote smoking cessation.

    PubMed

    Niederdeppe, Jeff; Farrelly, Matthew C; Nonnemaker, James; Davis, Kevin C; Wagner, Lauren

    2011-03-01

    There are large disparities in cigarette smoking rates by socioeconomic status (SES) in many countries. There is mixed evidence about the relative effectiveness of smoking cessation media campaigns in promoting quitting between lower and higher SES populations, and studies suggest that some types of ad content may have differential effects by SES. We analyzed data from five waves of the New York Media Tracking Survey Online (MTSO), a web survey involving over 7000 adult smokers conducted between 2007 and 2009, to assess SES variation in response to smoking cessation ads. Smokers with low levels of education and income less often recalled ads focused on how to quit, and perceived them as less effective, than ads using graphic imagery or personal testimonials to convey why to quit. Contrary to predictions offered by the Stages of Change Model, we found no evidence that variation in readiness to quit smoking explained patterns of response by education. Results offer guidance for theorists and campaign planners in developing campaigns that are likely to promote cessation among less educated populations. PMID:21316830

  6. Seasonal variations and aeration effects on water quality improvements and physiological responses of Nymphaea tetragona Georgi.

    PubMed

    Lu, Xiao-Ming; Lu, Peng-Zhen; Huang, Min-Sheng; Dai, Ling-Peng

    2013-01-01

    Seasonal variations and aeration effects on water quality improvements and the physiological responses of Nymphaea tetragona Georgi were investigated with mesocosm experiments. Plants were hydroponically cultivated in six purifying tanks (aerated, non-aerated) and the characteristics of the plants were measured. Water quality improvements in purifying tanks were evaluated by comparing to the control tanks. The results showed that continuous aeration affected the plant morphology and physiology. The lengths of the roots, petioles and leaf limbs in aeration conditions were shorter than in non-aeration conditions. Chlorophyll and soluble protein contents of the leaf limbs in aerated tanks decreased, while peroxidase and catalase activities of roots tissues increased. In spring and summer, effects of aeration on the plants were less than in autumn. Total nitrogen (TN) and ammonia nitrogen (NH4(+)-N) in aerated tanks were lower than in non-aerated tanks, while total phosphorus (TP) and dissolved phosphorus (DP) increased in spring and summer. In autumn, effects of aeration on the plants became more significant. TN, NH4(+)-N, TP and DP became higher in aerated tanks than in non-aerated tanks in autumn. This work provided evidences for regulating aeration techniques based on seasonal variations of the plant physiology in restoring polluted stagnant water. PMID:23819294

  7. Effects of Spectral and Temporal Variations in Gamma Ray Burst Parameters

    NASA Astrophysics Data System (ADS)

    Ejzak, L. M.; Melott, A. L.; Thomas, B. C.; Medvedev, M. V.

    2005-12-01

    It has previously been shown that a typical gamma ray burst could have significant effects on the Earth, including such considerations as ozone depletion and production of odd nitrogen compounds. These effects in turn contribute to processes such as DNA damage in organisms, increasing opacity of the atmosphere, and nitric acid rain. Our interest lies in the role that these processes may play in mass extinction events, in particular the Ordovician mass extinction 443 Mya. Here we investigate variations in certain burst parameters and the resulting variation in the severity of effect that the burst radiation has on the Earth's atmosphere. We extend the range of photon energies used in the model beyond the range used in previous studies, and model bursts with a number of different peak energies. We also alter the temporal profile of the radiation during the burst itself. This research is conducted with support from NASA's Astrobiology: Exobiology and Evolutionary Biology Program and in collaboration with NASA's Goddard Space Flight Center, and with supercomputer support from NCSA.

  8. Genetic variation, inbreeding and chemical exposure—combined effects in wildlife and critical considerations for ecotoxicology

    PubMed Central

    Brown, A. Ross; Hosken, David J.; Balloux, François; Bickley, Lisa K.; LePage, Gareth; Owen, Stewart F.; Hetheridge, Malcolm J.; Tyler, Charles R.

    2009-01-01

    Exposure to environmental chemicals can have negative consequences for wildlife and even cause localized population extinctions. Resistance to chemical stress, however, can evolve and the mechanisms include desensitized target sites, reduced chemical uptake and increased metabolic detoxification and sequestration. Chemical resistance in wildlife populations can also arise independently of exposure and may be spread by gene flow between populations. Inbreeding—matings between closely related individuals—can have negative fitness consequences for natural populations, and there is evidence of inbreeding depression in many wildlife populations. In some cases, reduced fitness in inbred populations has been shown to be exacerbated under chemical stress. In chemical testing, both inbred and outbred laboratory animals are used and for human safety assessments, iso-genic strains (virtual clones) of mice and rats are often employed that reduce response variation, the number of animals used and associated costs. In contrast, for environmental risk assessment, strains of animals are often used that have been selectively bred to maintain heterozygosity, with the assumption that they are better able to predict adverse effects in wild, genetically variable, animals. This may not necessarily be the case however, as one outbred strain may not be representative of another or of a wild population. In this paper, we critically discuss relationships between genetic variation, inbreeding and chemical effects with the intention of seeking to support more effective chemical testing for the protection of wildlife. PMID:19833649

  9. Understanding the current anatomical competence landscape: Comparing perceptions of program directors, residents, and fourth-year medical students.

    PubMed

    Fillmore, Erin P; Brokaw, James J; Kochhar, Komal; Nalin, Peter M

    2016-07-01

    A mixed methods survey of fourth-year medical students, resident physicians, and residency program directors at the Indiana University School of Medicine gathered perceptions of anatomical competence-defined as the anatomical education necessary for effective clinical practice. The survey items explored numerous aspects of anatomical competence, including the most effective modes of instruction, perceptions of readiness for clinical practice, and specific suggestions for improving anatomical education during medical school and residency. The response rate was 46% for fourth-year medical students, 47% for residents (as graduates from 137 medical schools), and 71% for program directors. A majority of students and residents reported that their course in Gross Anatomy prepared them well for clinical practice; that cadaveric dissection was important in the early development of their anatomical competence; and that placing a greater emphasis on clinical relevance in medical school would have improved their anatomical competence even further. However, in terms of anatomical preparedness upon entering residency, the program directors rated their residents less prepared than the residents rated themselves. All three groups agreed that there is need for additional opportunities for anatomical educational during medical school and residency. Suggestions for improving anatomical education included the following: providing more opportunities for cadaveric dissection during medical school and residency; more consistent teaching of anatomy for clinical practice; more workshops that review anatomy; and better integration of anatomy with the teaching of other subjects during medical school. Anat Sci Educ 9: 307-318. © 2015 American Association of Anatomists. PMID:26632977

  10. Large variations in the Holocene marine radiocarbon reservoir effect reflect ocean circulation and climatic changes

    NASA Astrophysics Data System (ADS)

    Hua, Quan; Webb, Gregory E.; Zhao, Jian-xin; Nothdurft, Luke D.; Lybolt, Matthew; Price, Gilbert J.; Opdyke, Bradley N.

    2015-07-01

    Accurate radiocarbon dating of marine samples requires knowledge of the marine radiocarbon reservoir effect. This effect for a particular site/region is generally assumed constant through time when calibrating marine 14C ages. However, recent studies have shown large temporal variations of several hundred to a couple of thousand years in this effect for a number of regions during the late Quaternary and Holocene. Here we report marine radiocarbon reservoir correction (ΔR) for Heron Reef and Moreton Bay in southwestern (SW) Pacific for the last 8 ka derived from 14C analysis of 230Th-dated corals. Most of our ΔR for the last ∼5.4 ka agree well with their modern value, but large ΔR variability of ∼410 yr (from trough to peak) with possible decadal/centennial fluctuations is evident for the period ∼5.4-8 ka. The latter time interval also has significant variations with similar features in previously published ΔR values for other sites in the Pacific, including southern Peru-northern Chile in southeastern (SE) Pacific, the South China Sea, Vanuatu and Papua New Guinea, with the largest magnitude of ∼920 yr from SE Pacific. The mechanisms for these large ΔR variations across the Pacific during the mid-Holocene are complex processes involving (1) changes in the quantity and 14C content of upwelled waters in tropical east Pacific (TEP) (frequency and intensity of ocean upwelling in the TEP, and contribution of Subantarctic Mode Water to the upwelled waters, which is influenced by the intensity and position of southern westerly winds), and (2) variations in ocean circulation associated with climate change (La Niña/El Niño conditions, intensity of easterly trade winds, positions of the Intertropical Convergence Zone and the South Pacific Convergence Zone), which control the spreading of the older upwelled surface waters in the TEP to the western sites. Our results imply the need for employing temporal changes in ΔR values, instead of constant (modern) values

  11. The Effect of Microstructural Variation on the Hydrogen Environment-Assisted Cracking of Monel K-500

    NASA Astrophysics Data System (ADS)

    Harris, Zachary D.; Dolph, Justin D.; Pioszak, Greger L.; Rincon Troconis, Brendy C.; Scully, John R.; Burns, James T.

    2016-07-01

    The influence of microstructural variation on hydrogen environment-assisted cracking (HEAC) of Monel K-500 was evaluated using five nominally peak-aged lots of material tested under slow-rising stress intensity loading while immersed in NaCl solution under cathodic polarizations. Minimal variation in HEAC resistance among material lots was observed for an applied potential of -950 mVSCE ( E app, vs saturated calomel), whereas lot-to-lot variability in the fracture morphology demonstrates a significant difference in the HEAC resistance at the less negative potential of -850 mVSCE, suggesting that relatively severe H environments produce sufficient crack-tip H to minimize the impact of metallurgical differences. Sensitivity analyses accomplished by varying the inputs used in decohesion-based, micromechanical models imply significant variations in HEAC resistance are possible for realistic changes in grain boundary toughness, hydrogen uptake behavior, and yield strength. Grain size, impurity segregation (including the effects of gettering elements), grain boundary character/connectivity, and crack path tortuosity are also considered in the context of HEAC susceptibility. Yield strength, global hydrogen content, as well as impurity segregation to grain boundaries, especially boron and sulfur, are speculatively considered to be the dominant contributions in determining HEAC resistance. Modifications that would incorporate the effects of grain boundary segregation are proposed for the K TH model; detailed validation of such changes require high-fidelity and quantitative inputs for the degree of grain boundary segregation. Regardless, fracture mechanics-based HEAC results, detailed microstructural characterization, and micromechanical modeling were successfully coupled to gain insights into the influences governing the microstructure-dependent HEAC susceptibility of Monel K-500.

  12. How to evaluate performance of prediction methods? Measures and their interpretation in variation effect analysis

    PubMed Central

    2012-01-01

    Background Prediction methods are increasingly used in biosciences to forecast diverse features and characteristics. Binary two-state classifiers are the most common applications. They are usually based on machine learning approaches. For the end user it is often problematic to evaluate the true performance and applicability of computational tools as some knowledge about computer science and statistics would be needed. Results Instructions are given on how to interpret and compare method evaluation results. For systematic method performance analysis is needed established benchmark datasets which contain cases with known outcome, and suitable evaluation measures. The criteria for benchmark datasets are discussed along with their implementation in VariBench, benchmark database for variations. There is no single measure that alone could describe all the aspects of method performance. Predictions of genetic variation effects on DNA, RNA and protein level are important as information about variants can be produced much faster than their disease relevance can be experimentally verified. Therefore numerous prediction tools have been developed, however, systematic analyses of their performance and comparison have just started to emerge. Conclusions The end users of prediction tools should be able to understand how evaluation is done and how to interpret the results. Six main performance evaluation measures are introduced. These include sensitivity, specificity, positive predictive value, negative predictive value, accuracy and Matthews correlation coefficient. Together with receiver operating characteristics (ROC) analysis they provide a good picture about the performance of methods and allow their objective and quantitative comparison. A checklist of items to look at is provided. Comparisons of methods for missense variant tolerance, protein stability changes due to amino acid substitutions, and effects of variations on mRNA splicing are presented. PMID:22759650

  13. Dominant dipole effect embedded in paleomagnetic secular variation in Taiwan region over the past 7500 years

    NASA Astrophysics Data System (ADS)

    Huang, Yin-Sheng; Lee, Teh-Quei; Wei, Kuo-Yen

    2014-09-01

    To study the Holocene paleomagnetic field in Taiwan area, we performed a series of magnetic experiments to a marine sediment core OR1-715-21 obtained from the offshore of eastern Taiwan during the OR1-715 cruise. Analyzed magnetic properties show that the remanent magnetization carriers of the core are uniformly dominated by single-domain and pseudo-single-domain magnetite, revealing a suitable material for relative paleointensity (RPI) estimation. The stable and well defined characteristic remanent magnetization (ChRM) provides the reliable determination of the inclination and declination. Dipole moments were further calculated by using the RPI and inclination data. The variation of the dipole moments compares well to the CALS10k.1b model (a continuous model of archaeomagnetic and lake sediment data for the past 10000 years), implying the dominance of the dipole field in Taiwan area. Though the real declination is unavailable because of lacking core orientation during coring, we could correct the values based on some critical conditions. If the paleosecular variation (PSV) is considered, the virtual geomagnetic pole (VGP) is generally suggested to vary between 80°N and 90°N instead of coinciding with the geography North Pole. To fit the condition considering the PSV effect, the ChRM declination had to be rotated 180° to get the corrected declination. As a result, variation patterns of the paleo-inclination, -declination, and paleointensity could be suitably determined in the study. Outcomes of these analyses reveal that the paleomagnetic field in Taiwan region should be dominantly driven from the dipole field under the PSV effect for the last 7500 years.

  14. The Effect of Microstructural Variation on the Hydrogen Environment-Assisted Cracking of Monel K-500

    NASA Astrophysics Data System (ADS)

    Harris, Zachary D.; Dolph, Justin D.; Pioszak, Greger L.; Rincon Troconis, Brendy C.; Scully, John R.; Burns, James T.

    2016-04-01

    The influence of microstructural variation on hydrogen environment-assisted cracking (HEAC) of Monel K-500 was evaluated using five nominally peak-aged lots of material tested under slow-rising stress intensity loading while immersed in NaCl solution under cathodic polarizations. Minimal variation in HEAC resistance among material lots was observed for an applied potential of -950 mVSCE (E app, vs saturated calomel), whereas lot-to-lot variability in the fracture morphology demonstrates a significant difference in the HEAC resistance at the less negative potential of -850 mVSCE, suggesting that relatively severe H environments produce sufficient crack-tip H to minimize the impact of metallurgical differences. Sensitivity analyses accomplished by varying the inputs used in decohesion-based, micromechanical models imply significant variations in HEAC resistance are possible for realistic changes in grain boundary toughness, hydrogen uptake behavior, and yield strength. Grain size, impurity segregation (including the effects of gettering elements), grain boundary character/connectivity, and crack path tortuosity are also considered in the context of HEAC susceptibility. Yield strength, global hydrogen content, as well as impurity segregation to grain boundaries, especially boron and sulfur, are speculatively considered to be the dominant contributions in determining HEAC resistance. Modifications that would incorporate the effects of grain boundary segregation are proposed for the K TH model; detailed validation of such changes require high-fidelity and quantitative inputs for the degree of grain boundary segregation. Regardless, fracture mechanics-based HEAC results, detailed microstructural characterization, and micromechanical modeling were successfully coupled to gain insights into the influences governing the microstructure-dependent HEAC susceptibility of Monel K-500.

  15. Long-range population dynamics of anatomically defined neocortical networks

    PubMed Central

    Chen, Jerry L; Voigt, Fabian F; Javadzadeh, Mitra; Krueppel, Roland; Helmchen, Fritjof

    2016-01-01

    The coordination of activity across neocortical areas is essential for mammalian brain function. Understanding this process requires simultaneous functional measurements across the cortex. In order to dissociate direct cortico-cortical interactions from other sources of neuronal correlations, it is furthermore desirable to target cross-areal recordings to neuronal subpopulations that anatomically project between areas. Here, we combined anatomical tracers with a novel multi-area two-photon microscope to perform simultaneous calcium imaging across mouse primary (S1) and secondary (S2) somatosensory whisker cortex during texture discrimination behavior, specifically identifying feedforward and feedback neurons. We find that coordination of S1-S2 activity increases during motor behaviors such as goal-directed whisking and licking. This effect was not specific to identified feedforward and feedback neurons. However, these mutually projecting neurons especially participated in inter-areal coordination when motor behavior was paired with whisker-texture touches, suggesting that direct S1-S2 interactions are sensory-dependent. Our results demonstrate specific functional coordination of anatomically-identified projection neurons across sensory cortices. DOI: http://dx.doi.org/10.7554/eLife.14679.001 PMID:27218452

  16. An anatomically realistic temperature phantom for radiofrequency heating measurements

    PubMed Central

    Graedel, Nadine N.; Polimeni, Jonathan R.; Guerin, Bastien; Gagoski, Borjan; Wald, Lawrence L.

    2014-01-01

    Purpose An anthropomorphic phantom with realistic electrical properties allows for a more accurate reproduction of tissue current patterns during excitation. A temperature map can then probe the worst-case heating expected in the un-perfused case. We describe an anatomically realistic human head phantom that allows rapid 3D temperature mapping at 7 T. Methods The phantom was based on hand-labeled anatomical imaging data and consists of four compartments matching the corresponding human tissues in geometry and electrical properties. The increases in temperature resulting from radiofrequency excitation were measured with MR thermometry using a temperature sensitive contrast agent (TmDOTMA−) validated by direct fiber optic temperature measurements. Results Acquisition of 3D temperature maps of the full phantom with a temperature accuracy better than 0.1°C was achieved with an isotropic resolution of 5 mm and acquisition times of 2–4 minutes. Conclusion Our results demonstrate the feasibility of constructing anatomically realistic phantoms with complex geometries incorporating the ability to measure accurate temperature maps in the phantom. The anthropomorphic temperature phantom is expected to provide a useful tool for the evaluation of the heating effects of both conventional and parallel transmit pulses and help validate electromagnetic and temperature simulations. PMID:24549755

  17. Long-range population dynamics of anatomically defined neocortical networks.

    PubMed

    Chen, Jerry L; Voigt, Fabian F; Javadzadeh, Mitra; Krueppel, Roland; Helmchen, Fritjof

    2016-01-01

    The coordination of activity across neocortical areas is essential for mammalian brain function. Understanding this process requires simultaneous functional measurements across the cortex. In order to dissociate direct cortico-cortical interactions from other sources of neuronal correlations, it is furthermore desirable to target cross-areal recordings to neuronal subpopulations that anatomically project between areas. Here, we combined anatomical tracers with a novel multi-area two-photon microscope to perform simultaneous calcium imaging across mouse primary (S1) and secondary (S2) somatosensory whisker cortex during texture discrimination behavior, specifically identifying feedforward and feedback neurons. We find that coordination of S1-S2 activity increases during motor behaviors such as goal-directed whisking and licking. This effect was not specific to identified feedforward and feedback neurons. However, these mutually projecting neurons especially participated in inter-areal coordination when motor behavior was paired with whisker-texture touches, suggesting that direct S1-S2 interactions are sensory-dependent. Our results demonstrate specific functional coordination of anatomically-identified projection neurons across sensory cortices. PMID:27218452

  18. The effects of variations in nuclear interactions on nucleosynthesis in thermonuclear supernovae

    NASA Astrophysics Data System (ADS)

    Parikh, A.; José, J.; Seitenzahl, I. R.; Röpke, F. K.

    2013-09-01

    of reactions would, however, help to further constrain model predictions. In addition, we confirm the need for a detailed, consistent treatment of all relevant stellar weak interaction rates since simultaneous variation of these rates (as opposed to individual variation) has a significant effect on yields in our models.

  19. Giving Ourselves: The Ethics of Anatomical Donation

    ERIC Educational Resources Information Center

    Gunderman, Richard B.

    2008-01-01

    In some European countries, such as Italy, medical education is threatened by a dearth of anatomical specimens. Such a shortage could spread to other nations, including the United States. This article addresses two ethical questions in body donation. Why might people choose to donate their bodies to education and science? What sorts of ethical…

  20. Evolution of the Anatomical Theatre in Padova

    ERIC Educational Resources Information Center

    Macchi, Veronica; Porzionato, Andrea; Stecco, Carla; Caro, Raffaele

    2014-01-01

    The anatomical theatre played a pivotal role in the evolution of medical education, allowing students to directly observe and participate in the process of dissection. Due to the increase of training programs in clinical anatomy, the Institute of Human Anatomy at the University of Padova has renovated its dissecting room. The main guidelines in…

  1. Effect of temperature variations and thermal noise on the static and dynamic behavior of straintronics devices

    NASA Astrophysics Data System (ADS)

    Barangi, Mahmood; Mazumder, Pinaki

    2015-11-01

    A theoretical model quantifying the effect of temperature variations on the magnetic properties and static and dynamic behavior of the straintronics magnetic tunneling junction is presented. Four common magnetostrictive materials (Nickel, Cobalt, Terfenol-D, and Galfenol) are analyzed to determine their temperature sensitivity and to provide a comprehensive database for different applications. The variations of magnetic anisotropies are studied in detail for temperature levels up to the Curie temperature. The energy barrier of the free layer and the critical voltage required for flipping the magnetization vector are inspected as important metrics that dominate the energy requirements and noise immunity when the device is incorporated into large systems. To study the dynamic thermal noise, the effect of the Langevin thermal field on the free layer's magnetization vector is incorporated into the Landau-Lifshitz-Gilbert equation. The switching energy, flipping delay, write, and hold error probabilities are studied, which are important metrics for nonvolatile memories, an important application of the straintronics magnetic tunneling junctions.

  2. Effects of dietary variation on growth, composition, and maturation of Manduca sexta (Sphingidae: Lepidoptera).

    PubMed

    Ojeda-Avila, T; Woods, H Arthur; Raguso, R A

    2003-04-01

    Most studies linking dietary variation with insect fitness focus on a single dietary component and late larval growth. We examined the effects of variation in multiple dietary factors over most life stages of the sphingid moth, Manduca sexta. Larvae received artificial diets in which protein, sucrose, and water content were varied. The relationship between larval size, growth and consumption rates differed significantly across diets. Larvae on control and low-sucrose diets grew most rapidly and attained the largest pupal and adult sizes. Conversely, larvae on low-water and low-protein diets initially grew slowly, but accelerated in the fifth instar and became pupae and adults comparable to control animals in size. There were no fundamental differences in protein:carbohydrate consumption patterns or strategies among experimental diets and larval instars. However, inadequate dietary water appeared to be more important for early than late instar larvae. Larvae on all artificial diets showed increasing fat content throughout all stages, including wandering and metamorphosis. Compensatory feeding among low-water and low-protein larvae was correlated with significantly higher fat content in larvae, pupae and adults, whereas low-sucrose animals were substantially leaner than those on the control diet. These differences may have strong effects on adult physiology, reproduction, and foraging patterns. PMID:12769983

  3. Effects of genotypic and phenotypic variation on establishment are important for conservation, invasion, and infection biology.

    PubMed

    Forsman, Anders

    2014-01-01

    There is abundant evidence that the probability of successful establishment in novel environments increases with number of individuals in founder groups and with number of repeated introductions. Theory posits that the genotypic and phenotypic variation among individuals should also be important, but few studies have examined whether founder diversity influences establishment independent of propagule pressure, nor whether the effect is model or context dependent. I summarize the results of 18 experimental studies and report on a metaanalysis that provides strong evidence that higher levels of genotypic and phenotypic diversity in founder groups increase establishment success in plants and animals. The effect of diversity is stronger in experiments carried out under natural conditions in the wild than under seminatural or standardized laboratory conditions. The realization that genetic and phenotypic variation is key to successful establishment may improve the outcome of reintroduction and translocation programs used to vitalize or restore declining and extinct populations. Founder diversity may also improve the ability of invasive species to establish and subsequently spread in environments outside of their native community, and enhance the ability of pathogens and parasites to colonize and invade the environment constituted by their hosts. It is argued that exchange of ideas, methodological approaches, and insights of the role of diversity for establishment in different contexts may further our knowledge, vitalize future research, and improve management plans in different disciplines. PMID:24367109

  4. Aldehyde dehydrogenase variation enhances effect of pesticides associated with Parkinson disease

    PubMed Central

    Fitzmaurice, Arthur G.; Rhodes, Shannon L.; Cockburn, Myles; Ritz, Beate

    2014-01-01

    Objective: The objective of this study was to determine whether environmental and genetic alterations of neuronal aldehyde dehydrogenase (ALDH) enzymes were associated with increased Parkinson disease (PD) risk in an epidemiologic study. Methods: A novel ex vivo assay was developed to identify pesticides that can inhibit neuronal ALDH activity. These were investigated for PD associations in a population-based case-control study, the Parkinson's Environment & Genes (PEG) Study. Common variants in the mitochondrial ALDH2 gene were genotyped to assess effect measure modification (statistical interaction) of the pesticide effects by genetic variation. Results: All of the metal-coordinating dithiocarbamates tested (e.g., maneb, ziram), 2 imidazoles (benomyl, triflumizole), 2 dicarboxymides (captan, folpet), and 1 organochlorine (dieldrin) inhibited ALDH activity, potentially via metabolic byproducts (e.g., carbon disulfide, thiophosgene). Fifteen screened pesticides did not inhibit ALDH. Exposures to ALDH-inhibiting pesticides were associated with 2- to 6-fold increases in PD risk; genetic variation in ALDH2 exacerbated PD risk in subjects exposed to ALDH-inhibiting pesticides. Conclusion: ALDH inhibition appears to be an important mechanism through which environmental toxicants contribute to PD pathogenesis, especially in genetically vulnerable individuals, suggesting several potential interventions to reduce PD occurrence or slow or reverse its progression. PMID:24491970

  5. The effect of local circulations on the variation of atmospheric pollutants in the northwestern Taiwan

    SciTech Connect

    Pay-Liam Lin; Hsin-Chih Lai

    1996-12-31

    A field experiment was held in the northwestern Taiwan as a part of a long-term research program for studying Taiwan`s local circulation. The program has been named as Taiwan Regional-circulation Experiment (TREX). The particular goal of this research is to investigate characteristics of boundary layer and local Circulation and their impact on the distribution and Variation of pollutants in the northwestern Taiwan during Mei-Yu season. It has been known for quite sometime that land-sea breeze is very pronounced under hot and humid conditions. Extensive network includes 11 pilot ballon stations, 3 acoustic sounding sites, and 14 surface stations in about 20 km by 20 km area centered at National Central University, Chung-Li. In addition, there are ground temperature measurements at 3 sites, Integrated Sounding System (ISS) at NCU, air plane observation, tracer experiment with 10 collecting stations, 3 background upper-air sounding stations, 2 towers etc. NOAA and GMS satellite data, sea surface temperature radar, and precipitation data are collected. The local circulations such as land/sea breezes and mountain/valley winds, induced by thermal and topographical effects often play an important role in transporting, redistributing and transforming atmospheric pollutants. This study documents the effects of the development of local circulations and the accompanying evolution of boundary layer on the distribution and the variation of the atmospheric pollutants in the north western Taiwan during Mei-Yu season.

  6. Anatomical Considerations on Surgical Anatomy of the Carotid Bifurcation

    PubMed Central

    Michalinos, Adamantios; Chatzimarkos, Markos; Arkadopoulos, Nikolaos; Safioleas, Michail

    2016-01-01

    Surgical anatomy of carotid bifurcation is of unique importance for numerous medical specialties. Despite extensive research, many aspects such as precise height of carotid bifurcation, micrometric values of carotid arteries and their branches as their diameter, length, and degree of tortuosity, and variations of proximal external carotid artery branches are undetermined. Furthermore carotid bifurcation is involved in many pathologic processes, atheromatous disease being the commonest. Carotid atheromatous disease is a major predisposing factor for disabling and possibly fatal strokes with geometry of carotid bifurcation playing an important role in its natural history. Consequently detailed knowledge of various anatomic parameters is of paramount importance not only for understanding of the disease but also for design of surgical treatment, especially selection between carotid endarterectomy and carotid stenting. Carotid bifurcation paragangliomas constitute unique tumors with diagnostic accuracy, treatment design, and success of operative intervention dependent on precise knowledge of anatomy. Considering those, it becomes clear that selection and application of proper surgical therapy should consider anatomical details. Further research might ameliorate available treatment options or even lead to innovative ones. PMID:27047690

  7. An anatomical and functional model of the human tracheobronchial tree.

    PubMed

    Florens, M; Sapoval, B; Filoche, M

    2011-03-01

    The human tracheobronchial tree is a complex branched distribution system in charge of renewing the air inside the acini, which are the gas exchange units. We present here a systematic geometrical model of this system described as a self-similar assembly of rigid pipes. It includes the specific geometry of the upper bronchial tree and a self-similar intermediary tree with a systematic branching asymmetry. It ends by the terminal bronchioles whose generations range from 8 to 22. Unlike classical models, it does not rely on a simple scaling law. With a limited number of parameters, this model reproduces the morphometric data from various sources (Horsfield K, Dart G, Olson DE, Filley GF, Cumming G. J Appl Physiol 31: 207-217, 1971; Weibel ER. Morphometry of the Human Lung. New York: Academic Press, 1963) and the main characteristics of the ventilation. Studying various types of random variations of the airway sizes, we show that strong correlations are needed to reproduce the measured distributions. Moreover, the ventilation performances are observed to be robust against anatomical variability. The same methodology applied to the rat also permits building a geometrical model that reproduces the anatomical and ventilation characteristics of this animal. This simple model can be directly used as a common description of the entire tree in analytical or numerical studies such as the computation of air flow distribution or aerosol transport. PMID:21183626

  8. Anatomical and functional characteristics of carotid sinus stimulation in humans

    NASA Technical Reports Server (NTRS)

    Querry, R. G.; Smith, S. A.; Stromstad, M.; Ide, K.; Secher, N. H.; Raven, P. B.

    2001-01-01

    Transmission characteristics of pneumatic pressure to the carotid sinus were evaluated in 19 subjects at rest and during exercise. Either a percutaneous fluid-filled (n = 12) or balloon-tipped catheter (n = 7) was placed at the carotid bifurcation to record internal transmission of external neck pressure/neck suction (NP/NS). Sustained, 5-s pulses, and rapid ramping pulse protocols (+40 to -80 Torr) were recorded. Transmission of pressure stimuli was less with the fluid-filled catheter compared with that of the balloon-tipped catheter (65% vs. 82% negative pressure, 83% vs. 89% positive pressure; P < 0.05). Anatomical location of the carotid sinus averaged 3.2 cm (left) and 3.6 cm (right) from the gonion of the mandible with a range of 0-7.5 cm. Transmission was not altered by exercise or Valsalva maneuver, but did vary depending on the position of the carotid sinus locus beneath the sealed chamber. These data indicate that transmission of external NP/NS was higher than previously recorded in humans, and anatomical variation of carotid sinus location and equipment design can affect transmission results.

  9. Variation among individuals in photoperiod responses: Effects of breeding schedule, photoperiod, and age-related photoperiodic experience in birds.

    PubMed

    Watts, Heather E; MacDougall-Shackleton, Scott A; Hahn, Thomas P

    2015-07-01

    Many organisms use environmental cues to regulate reproductive function in order to time reproduction to coincide with favorable environmental conditions. Whereas we understand much about how environmental cues are used to time reproduction, we know relatively little about variation among individuals in responsiveness to environmental cues. However, this variation among individuals may represent a crucial component of a population's capacity to respond to changing environmental conditions. In this study, we quantify variation among individuals in photoperiod responsiveness of the avian reproductive system and investigate three potential underlying sources of this variation in environmental cue responsiveness. Specifically, we tested whether age-related photoperiodic experience, strength of the photoperiodic cue (day length), and degree of flexibility in breeding schedule influenced the degree of variation observed in experimental studies of seven species of cardueline finches. Overall, we found a high degree of variation among individuals in photoperiod response, and this was influenced by experimental photoperiod and breeding schedule. As experimental photoperiod became longer, the degree of variation declined. Opportunistic breeders showed greater variation in response compared with more seasonal breeders. We found no effect of age-related photoperiodic experience in one species for which we could examine this factor. The results of this study highlight the extent to which individuals can vary in their response to environmental cues and point to both species ecology and characteristics of the cue as important influences on the degree of this variation. PMID:25865942

  10. [Topographic features of lingual nerve and its relationship with other anatomical structures in maxillolingual groove].

    PubMed

    Dyidyikin, S S; Syomkin, V A; Kuzin, A V; Sogacheva, V V

    2016-01-01

    By surgical interventions in maxillolingual groove area one should consider anatomical variations and topography of vessels, glands ducts and lingual nerve to prevent their injury. At the Department of Operative Surgery and Topographic Anatomy of the First Moscow State Medical University named after I.M. Sechenov we carried out anatomical study on cadavers (men and women, n=30).The study revealed topographical features of the lingual nerve and its relationship to other anatomical structures in the maxillolingual groove. It was found out that at the level of the second molar (96%) lingual nerve "crosses" duct of submandibular salivary gland, at the level of the third molar lingual nerve is located under the duct and lateral to it, closer to the inner surface of the body of the mandible. At the level of the first molar lingual nerve is located above and medial to Wharton duct and passes along sublingual-lingual muscles (m.hyoglossus). PMID:26925560

  11. Effects of magnitude and frequency of variations in external power output on simulated cycling time-trial performance.

    PubMed

    Wells, Marc; Atkinson, Greg; Marwood, Simon

    2013-01-01

    Mechanical models of cycling time-trial performance have indicated adverse effects of variations in external power output on overall performance times. Nevertheless, the precise influences of the magnitude and number of these variations over different distances of time trial are unclear. A hypothetical cyclist (body mass 70 kg, bicycle mass 10 kg) was studied using a mathematical model of cycling, which included the effects of acceleration. Performance times were modelled over distances of 4-40 km, mean power outputs of 200-600 W, power variation amplitudes of 5-15% and variation frequencies of 2-32 per time-trial. Effects of a "fast-start" strategy were compared with those of a constant-power strategy. Varying power improved 4-km performance at all power outputs, with the greatest improvement being 0.90 s for ± 15% power variation. For distances of 16.1, 20 and 40 km, varying power by ± 15% increased times by 3.29, 4.46 and 10.43 s respectively, suggesting that in long-duration cycling in constant environmental conditions, cyclists should strive to reduce power variation to maximise performance. The novel finding of the present study is that these effects are augmented with increasing event distance, amplitude and period of variation. These two latter factors reflect a poor adherence to a constant speed. PMID:23711074

  12. Annual Variation of The Biological Effective Uv Dose On The Martian Surface

    NASA Astrophysics Data System (ADS)

    Patel, M. R.; Bercés, A.; Kerékgyártó, T.; Lammer, H.; Kolb, C.; Zarnecki, J. C.; Selsis, F.

    We have developed and implemented a spectral-element method (SEM) to simulate seismic wave propagation throughout the entire globe. Our SEM incorporates the effects of fluid-solid boundaries, attenuation, anisotropy, the oceans, rotation, self- gravitation and 3-D mantle and crustal heterogeneity. The method is implemented on a massively parallel PC cluster computer using message-passing software (MPI). The effects of crustal thickness, anisotropy, and attenuation on surface waves are quite dramatic. Self-gravitation and, in particular, the presence of a water layer slow the Rayleigh wave down. For spherically symmetric Earth models the SEM is in excellent agreement with normal-mode synthetics at periods greater than 20 seconds. We use the SEM to assess the quality of mantle model S20RTS, developed by Ritsema and colleagues. The effects of 3-D heterogeneity can be spectacular. For example, along oceanic paths from Fiji-Tonga to Western North America or Japan the Rayleigh wave arrives more than a minute earlier than in PREM, and the Love wave exhibits very little dispersion, unlike in PREM. These effects are largely due to the fact that the oceanic crust is much thinner than in PREM. For a set of well-recorded earthquakes we use the SEM to determine how well model S20RTS fits the travel-time data. Be- cause the SEM synthetics are essentially exact at periods greater than 20 seconds, this facilitates a difficult test for a 3-D model. For paths between South America and Africa, the SEM and model S20RTS produce 10 second delays in the S wave that are observed in the data We also show that global variations in PP/P amplitude anomalies are largely a result of variations in crustal thickness and are well predicted by the SEM and crustal model CRUST5.2, developed by Bassin and colleagues. In contrast, SS/S amplitude anoma- lies are not nearly as well predicted by the SEM and models S20RTS and crust5.2. This probably reflects lateral variations in attenuation which are not

  13. Genetic variation and structure of house sparrow populations: is there an island effect?

    PubMed

    Jensen, Henrik; Moe, Rune; Hagen, Ingerid Julie; Holand, Anna Marie; Kekkonen, Jaana; Tufto, Jarle; Saether, Bernt-Erik

    2013-04-01

    Population genetic structure and intrapopulation levels of genetic variation have important implications for population dynamics and evolutionary processes. Habitat fragmentation is one of the major threats to biodiversity. It leads to smaller population sizes and reduced gene flow between populations and will thus also affect genetic structure. We use a natural system of island and mainland populations of house sparrows along the coast of Norway to characterize the different population genetic properties of fragmented populations. We genotyped 636 individuals distributed across 14 populations at 15 microsatellite loci. The level of genetic differentiation was estimated using F-statistics and specially designed Mantel tests were conducted to study the influence of population type (i.e. mainland or island) and geographic distance on the genetic population structure. Furthermore, the effects of population type, population size and latitude on the level of genetic variation within populations were examined. Our results suggest that genetic processes on islands and mainland differed in two important ways. First, the intrapopulation level of genetic variation tended to be lower and the occurrence of population bottlenecks more frequent on islands than the mainland. Second, although the general level of genetic differentiation was low to moderate, it was higher between island populations than between mainland populations. However, differentiation increased in mainland populations somewhat faster with geographical distance. These results suggest that population bottleneck events and genetic drift have been more important in shaping the genetic composition of island populations compared with populations on the mainland. Such knowledge is relevant for a better understanding of evolutionary processes and conservation of threatened populations. PMID:23379682

  14. Gate line edge roughness amplitude and frequency variation effects on intra die MOS device characteristics

    NASA Astrophysics Data System (ADS)

    Hamadeh, Emad; Gunther, Norman G.; Niemann, Darrell; Rahman, Mahmud

    2006-06-01

    Random fluctuations in fabrication process outcomes such as gate line edge roughness (LER) give rise to corresponding fluctuations in scaled down MOS device characteristics. A thermodynamic-variational model is presented to study the effects of LER on threshold voltage and capacitance of sub-50 nm MOS devices. Conceptually, we treat the geometric definition of the MOS devices on a die as consisting of a collection of gates. In turn, each of these gates has an area, A, and a perimeter, P, defined by nominally straight lines subject to random process outcomes producing roughness. We treat roughness as being deviations from straightness consisting of both transverse amplitude and longitudinal wavelength each having lognormal distribution. We obtain closed-form expressions for variance of threshold voltage ( Vth), and device capacitance ( C) at Onset of Strong Inversion (OSI) for a small device. Using our variational model, we characterized the device electrical properties such as σ and σC in terms of the statistical parameters of the roughness amplitude and spatial frequency, i.e., inverse roughness wavelength. We then verified our model with numerical analysis of Vth roll-off for small devices and σ due to dopant fluctuation. Our model was also benchmarked against TCAD of σ as a function of LER. We then extended our analysis to predict variations in σ and σC versus average LER spatial frequency and amplitude, and oxide-thickness. Given the intuitive expectation that LER of very short wavelengths must also have small amplitude, we have investigated the case in which the amplitude mean is inversely related to the frequency mean. We compare with the situation in which amplitude and frequency mean are unrelated. Given also that the gate perimeter may consist of different LER signature for each side, we have extended our analysis to the case when the LER statistical difference between gate sides is moderate, as well as when it is significantly large.

  15. Effects of Solar Activity Variation on the Low Latitude Topside Nighttime Ionosphere

    NASA Astrophysics Data System (ADS)

    Min, K. W.; Kim, H.; Park, J.; Park, S.; Lee, J.; Lee, E.

    2006-05-01

    We investigate the effects of solar activity variation on the topside nighttime ionosphere of the low latitude region using the DMSP F15 data taken at 840 km altitude as well as the KOMPSAT-1 data taken at 685 km altitude. The change of the ionospheric parameters shows a good correlation with F 10.7 variations, in accordance with 27-day solar rotations. The correlation is especially good when a time delay of 1 to 2 days is incorporated and when the F 10.7 variation is large. Vertical drift velocities and the oxygen ion fractions, observed by DMSP F15, are also seen to have good correlations with F 10.7 with similar time delays. We suspect the delayed correlation of the ionospheric response is closely related to the neutral density changes affected by the solar activity as it has been reported that changes in the solar soft X-rays and the neutral density are well correlated with a delay of approximately 1.5 days. We also compare the ionospheric response for the solar maximum period with that of the declining phase using the data for the period 2000 through 2004 during which average F 10.7 varied from over 200 to around 100. The density does not seem to saturate at high F 10.7 values even during the solar maximum phase, in contrast to the daytime ionospheric response reported previously. The density during the low solar activity cycle is observed to be lower than that of the high solar activity for the same F 10.7 values, implying the long term dependence of the ionosphere in addition to the prompt response of 1 to 2 days.

  16. Facial reconstruction – anatomical art or artistic anatomy?

    PubMed Central

    Wilkinson, Caroline

    2010-01-01

    Facial reconstruction is employed in the context of forensic investigation and for creating three-dimensional portraits of people from the past, from ancient Egyptian mummies and bog bodies to digital animations of J. S. Bach. This paper considers a facial reconstruction method (commonly known as the Manchester method) associated with the depiction and identification of the deceased from skeletal remains. Issues of artistic licence and scientific rigour, in relation to soft tissue reconstruction, anatomical variation and skeletal assessment, are discussed. The need for artistic interpretation is greatest where only skeletal material is available, particularly for the morphology of the ears and mouth, and with the skin for an ageing adult. The greatest accuracy is possible when information is available from preserved soft tissue, from a portrait, or from a pathological condition or healed injury. PMID:20447245

  17. Autotetraploid rice methylome analysis reveals methylation variation of transposable elements and their effects on gene expression

    PubMed Central

    Zhang, Jie; Liu, Yuan; Xia, En-Hua; Yao, Qiu-Yang; Liu, Xiang-Dong; Gao, Li-Zhi

    2015-01-01

    Polyploidy, or whole-genome duplication (WGD), serves as a key innovation in plant evolution and is an important genomic feature for all eukaryotes. Neopolyploids have to overcome difficulties in meiosis, genomic alterations, changes of gene expression, and epigenomic reorganization. However, the underlying mechanisms for these processes are poorly understood. One of the most interesting aspects is that genome doubling events increase the dosage of all genes. Unlike allopolyploids entangled by both hybridization and polyploidization, autopolyploids, especially artificial lines, in relatively uniform genetic background offer a model system to understand mechanisms of genome-dosage effects. To investigate DNA methylation effects in response to WGD rather than hybridization, we produced autotetraploid rice with its diploid donor, Oryza sativa ssp. indica cv. Aijiaonante, both of which were independently self-pollinated over 48 generations, and generated and compared their comprehensive transcriptomes, base pair-resolution methylomes, and siRNAomes. DNA methylation variation of transposable elements (TEs) was observed as widespread in autotetraploid rice, in which hypermethylation of class II DNA transposons was predominantly noted in CHG and CHH contexts. This was accompanied by changes of 24-nt siRNA abundance, indicating the role of the RNA-directed DNA methylation pathway. Our results showed that the increased methylation state of class II TEs may suppress the expression of neighboring genes in autotetraploid rice that has obtained double alleles, leading to no significant differences in transcriptome alterations for most genes from its diploid donor. Collectively, our findings suggest that chromosome doubling induces methylation variation in TEs that affect gene expression and may become a “genome shock” response factor to help neoautopolyploids adapt to genome-dosage effects. PMID:26621743

  18. Increased interstitial loading reduces the effect of microstructural variations in cardiac tissue

    PubMed Central

    Henriquez, Craig S.

    2010-01-01

    Electrical propagation in diseased and aging hearts is strongly influenced by structural changes that occur in both the intracellular and interstitial spaces of cardiac tissue; however, very few studies have investigated how interactions between the two spaces affect propagation at the microscale. In this study, we used one-dimensional microstructural computer models of interconnected ventricular myocytes to systematically investigate how increasing the effective interstitial resistivity (ρoeff) influences action potential propagation in fibers with variations in intracellular properties such as cell coupling and cell length. Changes in ρoeff were incorporated into a monodomain model using a correction to the intracellular properties that was based on bidomain simulations. The results showed that increasing ρoeff in poorly coupled one-dimensional fibers alters the distribution of electrical load at the microscale and causes propagation to become more continuous. In the poorly coupled fiber, this continuous state is characterized by decreased gap junction delay, sustained conduction velocity, increased sodium current, reduced maximum upstroke velocity, and increased safety factor. Long, poorly coupled cells experience greater loading effects than short cells and show the greatest initial response to changes in ρoeff. In inhomogeneous fibers with adjacent well-coupled and poorly coupled regions, increasing ρoeff in the poorly coupled region also reduces source-load mismatch, which delays the onset of conduction block and reduces the dispersion of repolarization at the transition between the two regions. Increasing the ρoeff minimizes the effect of cell-to-cell variations and may influence the pattern of activation in critical regimes characterized by low intercellular coupling, microstructural heterogeneity, and reduced or abnormal membrane excitability. PMID:20097772

  19. The effect of adaptive mutagenesis on genetic variation at a linked, neutral locus

    SciTech Connect

    Colby, C.; Williams, S.M.

    1995-07-01

    Based on recent studies in single-celled organisms, it has been argued that a fitness benefit associated with a mutation will increase the probability of that mutation occurring. This increase is independent of mutation rates at other loci and is called adaptive mutagenesis. We modeled the effect of adaptive mutagenesis on populations of haploid organisms with adaptive mutation rates ranging from 0 to 1 x 10{sup -5}. Allele frequencies at the selected locus and a neutral linked locus were tracked. We also observed the amount of linkage disequilibrium during the selective sweep and the final heterozygosity after the sweep. The presence of adaptive mutagenesis increases the number of genetic backgrounds carrying the new fitter allele, making the outcomes more representative of the population before the selection. Therefore, more neutral genetic variation is preserved in simulations with adaptive mutagenesis than in those without it due to hitchhiking. Since adaptive mutagensis is time-dependent, it can generate mutants when other mechanisms of mutation cannot. In addition, adaptive mutagenesis has the potential to confound both phylogeny construction and the detection of natural selection from patterns of nucleotide variation. 27 refs., 4 figs.

  20. Effects of life history variation on vertical transfer of toxicants in marine mammals.

    PubMed

    Noonburg, Erik G; Nisbet, Roger M; Klanjscek, Tin

    2010-05-21

    Toxicant bioaccumulation poses a risk to many marine mammal populations. Although individual-level toxicology has been the subject of considerable research in several species, we lack a theoretical framework to generalize the results across environments and life histories. Here we formulate a dynamic energy budget model to predict the effects of intra- and interspecific life history variation on toxicant dynamics in marine mammals. Dynamic energy budget theory attempts to describe the most general processes of energy acquisition and utilization in heterotrophs. We tailor the basic model to represent the marine mammal reproductive cycle, and we add a model of toxicant uptake and partitioning to describe vertical transfer of toxicants from mother to offspring during gestation and lactation. We first show that the model predictions are consistent with qualitative patterns reported in empirical studies and previous species-specific modeling studies. Next, we use this model to examine the dependence of offspring toxicant load on birth order, food density, and interspecific life history variation. PMID:20171232

  1. Effect of Variations in IRU Integration Time Interval On Accuracy of Aqua Attitude Estimation

    NASA Technical Reports Server (NTRS)

    Natanson, G. A.; Tracewell, Dave

    2003-01-01

    During Aqua launch support, attitude analysts noticed several anomalies in Onboard Computer (OBC) rates and in rates computed by the ground Attitude Determination System (ADS). These included: 1) periodic jumps in the OBC pitch rate every 2 minutes; 2) spikes in ADS pitch rate every 4 minutes; 3) close agreement between pitch rates computed by ADS and those derived from telemetered OBC quaternions (in contrast to the step-wise pattern observed for telemetered OBC rates); 4) spikes of +/- 10 milliseconds in telemetered IRU integration time every 4 minutes (despite the fact that telemetered time tags of any two sequential IRU measurements were always 1 second apart from each other). An analysis presented in the paper explains this anomalous behavior by a small average offset of about 0.5 +/- 0.05 microsec in the time interval between two sequential accumulated angle measurements. It is shown that errors in the estimated pitch angle due to neglecting the aforementioned variations in the integration time interval by the OBC is within +/- 2 arcseconds. Ground attitude solutions are found to be accurate enough to see the effect of the variations on the accuracy of the estimated pitch angle.

  2. Temperature variation effects on sparse representation of guided-waves for damage diagnosis in pipelines

    NASA Astrophysics Data System (ADS)

    Eybpoosh, Matineh; Berges, Mario; Noh, Hae Young

    2015-04-01

    Multiple ultrasonic guided-wave modes propagating along a pipe travel with different velocities which are themselves a function of frequency. Reflections from the features of the structure (e.g., boundaries, pipe welding, damage, etc.), and their complex superposition, adds to the complexity of guided-waves. Guided-wave based damage diagnosis of pipelines becomes even more challenging when environmental and operational conditions (EOCs) vary (e.g., temperature, flow rate, inner pressure, etc.). These complexities make guided-wave based damage diagnosis of operating pipelines a challenging task. This paper reviews the approaches to-date addressing these challenges, and highlights the preferred characteristics of a method that simplifies guided-wave signals for damage diagnosis purposes. A method is proposed to extract a sparse subset of guided-wave signals in time-domain, while retaining optimal damage information for detection purpose. In this paper, the general concept of this method is proved through an extensive set of experiments. Effects of temperature variation on detection performance of the proposed method, and on discriminatory power of the extracted damage-sensitive features are investigated. The potential of the proposed method for real-time damage detection is illustrated, for wide range of temperature variation scenarios (i.e., temperature difference between training and test data varying between -2°C and 13°C).

  3. Effects of random stiffness variations in multistage rotors using the Polynomial Chaos Expansion

    NASA Astrophysics Data System (ADS)

    Seguí, B.; Faverjon, B.; Jacquet-Richardet, G.

    2013-09-01

    The paper presents a methodology that allows the investigation of the effects of random uncertainties on the global dynamics of multistage bladed discs systems. Uncertainties are accounted for as variations in the material properties of the blades. The multistage cyclic symmetry assumption is used to reduce the global problem. The random dynamics of the global system is obtained by applying the Polynomial Chaos Expansion. The methodology is applied to a two stage bladed disc assembly and the results of modal and forced response analysis are validated by comparisons with Monte-Carlo simulations. Possible interactions of multistage mode families in zones of high modal density due to uncertainties in the blades are discussed. Results obtained show that uncertainties may induce significant changes in the global dynamics of multistage assemblies and the proposed technique is shown to be efficient to capture those changes. The study classically evaluates the variations of frequencies and responses but also shows that the nature of mode shapes may be drastically affected by uncertainties.

  4. The Effect of Hardenability Variation on Phase Transformation of Spiral Bevel Gear in Quenching Process

    NASA Astrophysics Data System (ADS)

    Zhang, Yingtao; Shi, Wankai; Yang, Lin; Gu, Zhifei; Li, Zhichao

    2016-05-01

    The hardenability of gear steel is dependent on the composition of alloying elements and is one of important criteria to assess process of phase transformation. The variation of hardenability has to be considered in control of the microstructures and distortion during gear quenching. In this paper, the quantitative effect of hardenability has been investigated on phase transformations of spiral bevel gears in die quenching. The hardenability deviation of 22CrMoH steel was assessed by using Jominy test. The dilatometry experiments were conducted to build phase transformation kinetic models for steels with low and high hardenability, respectively. The complete die quenching process of spiral bevel gear was modeled to reveal the significant difference on microstructures and temperature history with variation of hardenability. The final microstructures of the gear are martensite in surface layer after quenching process. There are bainite inside the gear tooth and the mixture of bainite and ferrite inside gear for the gear with low hardenability. The microstructure is bainite inside the gear with high hardenability.

  5. Effects of seed traits variation on seedling performance of the invasive weed, Ambrosia artemisiifolia L.

    NASA Astrophysics Data System (ADS)

    Ortmans, William; Mahy, Grégory; Monty, Arnaud

    2016-02-01

    Seedling performance can determine the survival of a juvenile plant and impact adult plant performance. Understanding the factors that may impact seedling performance is thus critical, especially for annuals, opportunists or invasive plant species. Seedling performance can vary among mothers or populations in response to environmental conditions or under the influence of seed traits. However, very few studies have investigated seed traits variations and their consequences on seedling performance. Specifically, the following questions have been addressed by this work: 1) How the seed traits of the invasive Ambrosia artemisiifolia L. vary among mothers and populations, as well as along the latitude; 2) How do seed traits influence seedling performance; 3) Is the influence on seedlings temperature dependent. With seeds from nine Western Europe ruderal populations, seed traits that can influence seedling development were measured. The seeds were sown into growth chambers with warmer or colder temperature treatments. During seedling growth, performance-related traits were measured. A high variability in seed traits was highlighted. Variation was determined by the mother identity and population, but not latitude. Together, the temperature, population and the identity of the mother had an effect on seedling performance. Seed traits had a relative impact on seedling performance, but this did not appear to be temperature dependent. Seedling performance exhibited a strong plastic response to the temperature, was shaped by the identity of the mother and the population, and was influenced by a number of seed traits.

  6. Effects of life history variation on size and growth in stream-dwelling Atlantic salmon

    USGS Publications Warehouse

    Letcher, B.H.; Gries, G.

    2003-01-01

    A large size variation amongst life histories for stream-dwelling Atlantic salmon Salmo salar was found and the relative effect of life histories on size varied over time. As early as December (age 0+ years), fish that later smolted at age 2+ years were significantly larger than fish that did not smolt at age 2+ years. In contrast, there were no mass differences at age 0+ years between fish that would mature or not at age 1+ years (October). The mass differences between smolts and non-smolts persisted until smolting, and differences between mature and immature fish first appeared in May (age 1+ years). Following September (age 1+ years), there was also a significant interaction between smolting and maturity. Previously mature and immature age 2+ year smolts were not significantly different in size, but immature age 2+ year non-smolts were much lighter than mature age 2+ year non-smolts. Based on mass differences, the apparent 'decision' to smolt occurred c. 5 months before (winter, age 0+ years) the decision to mature (late spring, age 1+ years). In addition to strong seasonal growth variation, sizes of freshwater Atlantic salmon were largely structured by the complex interaction between smolt-age and maturity. ?? 2003 The fisheries Society of the British Isles.

  7. Recruitment variation of eastern Bering Sea crabs: Climate-forcing or top-down effects?

    NASA Astrophysics Data System (ADS)

    Zheng, Jie; Kruse, Gordon H.

    2006-02-01

    During the last three decades, population abundances of eastern Bering Sea (EBS) crab stocks fluctuated greatly, driven by highly variable recruitment. In recent years, abundances of these stocks have been very low compared to historical levels. This study aims to understand recruitment variation of six stocks of red king ( Paralithodes camtschaticus), blue king ( P. platypus), Tanner ( Chionoecetes bairdi), and snow ( C. opilio) crabs in the EBS. Most crab recruitment time series are not significantly correlated with each other. Spatial distributions of three broadly distributed crab stocks (EBS snow and Tanner crabs and Bristol Bay red king crab) have changed considerably over time, possibly related in part to the regime shift in climate and physical oceanography in 1976-1977. Three climate-forcing hypotheses on larval survival have been proposed to explain crab recruitment variation of Bristol Bay red king crab and EBS Tanner and snow crabs. Some empirical evidence supports speculation that groundfish predation may play an important role in crab recruitment success in the EBS. However, spatial dynamics in the geographic distributions of groundfish and crabs over time make it difficult to relate crab recruitment strength to groundfish biomass. Comprehensive field and spatially explicit modeling studies are needed to test the hypotheses and better understand the relative importance and compound effects of bottom-up and top-down controls on crab recruitment.

  8. The Effect of Hardenability Variation on Phase Transformation of Spiral Bevel Gear in Quenching Process

    NASA Astrophysics Data System (ADS)

    Zhang, Yingtao; Shi, Wankai; Yang, Lin; Gu, Zhifei; Li, Zhichao

    2016-07-01

    The hardenability of gear steel is dependent on the composition of alloying elements and is one of important criteria to assess process of phase transformation. The variation of hardenability has to be considered in control of the microstructures and distortion during gear quenching. In this paper, the quantitative effect of hardenability has been investigated on phase transformations of spiral bevel gears in die quenching. The hardenability deviation of 22CrMoH steel was assessed by using Jominy test. The dilatometry experiments were conducted to build phase transformation kinetic models for steels with low and high hardenability, respectively. The complete die quenching process of spiral bevel gear was modeled to reveal the significant difference on microstructures and temperature history with variation of hardenability. The final microstructures of the gear are martensite in surface layer after quenching process. There are bainite inside the gear tooth and the mixture of bainite and ferrite inside gear for the gear with low hardenability. The microstructure is bainite inside the gear with high hardenability.

  9. Effect of Heavy Metals Pollution on Soil Microbial Diversity and Bermudagrass Genetic Variation

    PubMed Central

    Xie, Yan; Fan, Jibiao; Zhu, Weixi; Amombo, Erick; Lou, Yanhong; Chen, Liang; Fu, Jinmin

    2016-01-01

    Heavy metal pollution is a serious global environmental problem as it adversely affects plant growth and genetic variation. It also alters the composition and activity of soil microbial communities. The objectives of this study were to determine the soil microbial diversity, bermudagrass genetic variation in Cd contaminated or uncontaminated soils from Hunan province of China, and to evaluate Cd-tolerance of bermudagrass at different soils. The Biolog method, hydroponic experiments and simple sequence repeat markers were used to assess the functional diversity of microorganisms, Cd-tolerance and the genetic diversity of bermudagrass, respectively. Four of the sampling sites were heavily contaminated with heavy metals. The total bioactivity, richness, and microbial diversity decreased with increasing concentration of heavy metal. The hydroponic experiment revealed that bermudagrass populations collected from polluted sites have evolved, encompassing the feature of a higher resistance to Cd toxicity. Higher genetic diversity was observed to be more in contaminated populations than in uncontaminated populations. Heavy metal pollution can result in adverse effects on plant growth, soil microbial diversity and activity, and apparently has a stronger impact on the genetic structure. The results of this study provide new insights and a background to produce a genetic description of populations in a species that is suitable for use in phytoremediation practices. PMID:27303431

  10. Effect of Heavy Metals Pollution on Soil Microbial Diversity and Bermudagrass Genetic Variation.

    PubMed

    Xie, Yan; Fan, Jibiao; Zhu, Weixi; Amombo, Erick; Lou, Yanhong; Chen, Liang; Fu, Jinmin

    2016-01-01

    Heavy metal pollution is a serious global environmental problem as it adversely affects plant growth and genetic variation. It also alters the composition and activity of soil microbial communities. The objectives of this study were to determine the soil microbial diversity, bermudagrass genetic variation in Cd contaminated or uncontaminated soils from Hunan province of China, and to evaluate Cd-tolerance of bermudagrass at different soils. The Biolog method, hydroponic experiments and simple sequence repeat markers were used to assess the functional diversity of microorganisms, Cd-tolerance and the genetic diversity of bermudagrass, respectively. Four of the sampling sites were heavily contaminated with heavy metals. The total bioactivity, richness, and microbial diversity decreased with increasing concentration of heavy metal. The hydroponic experiment revealed that bermudagrass populations collected from polluted sites have evolved, encompassing the feature of a higher resistance to Cd toxicity. Higher genetic diversity was observed to be more in contaminated populations than in uncontaminated populations. Heavy metal pollution can result in adverse effects on plant growth, soil microbial diversity and activity, and apparently has a stronger impact on the genetic structure. The results of this study provide new insights and a background to produce a genetic description of populations in a species that is suitable for use in phytoremediation practices. PMID:27303431

  11. Effects of satellite data resolution on measuring the space/time variations of surfaces and clouds

    NASA Technical Reports Server (NTRS)

    Seze, Genevieve; Rossow, William B.

    1991-01-01

    The correlated distributions of satellite-measured visible and infrared radiances, caused by spatial and temporal variations in clouds and surfaces, have been found to be characteristic of the major climate regimes and can be described by the attributes of bidimensional and monodimensional histograms and time-composite images. Most of the variability of both the surfaces and clouds is found to occur at scales larger than the minimum resolved by satellite imagery. Since satellite imaging data sets are difficult to analyze because of their large volumes, many studies reduce the volume by various sampling or averaging schemes. The effects of data resolution and sampling on the radiance histogram statistics and on the time-composite image characteristics are examined. In particular, the sampling strategy used by the International Satellite Cloud Climatology Project is tested. This sampling strategy is found to preserve the statistics of smaller cloud variations for most regions, with the exception of very rare events, if they are accumulated over large enough areas (at least 500 km in dimension) and long enough time periods (at least one month).

  12. Component variations and their effects on bipolar nickel-hydrogen cell performance

    NASA Technical Reports Server (NTRS)

    Manzo, Michelle A.; Gahn, Randall F.; Gonzalez-Sanabria, Olga D.; Cataldo, Robert L.; Gemeiner, Russel P.

    1987-01-01

    A 50 cell bipolar nickel-hydrogen battery was assembled to demonstrate the feasibility of constructing a high voltage stack of cells. Various component combinations were tested in this battery. The battery had approximately 1 ampere-hour of capacity and was constructed from components with an active area of 2" X 2". The components were parametrically varied to give a comparison of nickel electrodes, hydrogen electrodes, separators, fill procedures and electrolyte reservoir plate thicknesses. Groups of five cells were constructed using the same components; ten combinations were tested in all. The battery was thoroughly characterized at various change and discharge rates as well as with various pulse patterns and rates. Over a period of 1400 40% DOD LEO cycles some of the groups began to exhibit performance differences. In general, only separator variations had a significant effect on cell performance. It also appears that shunt currents may have been operating within the stack, resulting in electrolyte transfer from one cell to another, thus contributing to cell performance variations.

  13. Component variations and their effects on bipolar nickel-hydrogen cell performance

    NASA Technical Reports Server (NTRS)

    Manzo, Michelle A.; Gahn, Randall F.; Gonzalez-Sanabria, Olga D.; Cataldo, Robert L.; Gemeiner, Russel P.

    1987-01-01

    A 50 cell bipolar nickel-hydrogen battery was assembled to demonstrate the feasibility of constructing a high voltage stack of cells. Various component combinations were tested in this battery. The battery had approximately 1 ampere-hour of capacity and was constructed from components with an active area of 2 x 2 inches. The components were parametrically varied to give a comparison of nickel electrodes, hydrogen electrodes, separators, fill procedures and electrolyte reservoir plate thicknesses. Groups of five cells were constructed using the same components; ten combinations were tested in all. The battery was thoroughly characterized at various change and discharge rates as well as with various pulse patterns and rates. Over a period of 1400 40-percent DOD LEO cycles some of the groups began to exhibit performance differences. In general, only separator variations had a significant effect on cell performance. It also appears that shunt currents may have been operating within the stack, resulting in electrolyte transfer from one cell to another, thus contributing to cell performance variations.

  14. Chronobiological variations in the convulsive effect of monosodium L-glutamate when administered to adult rats.

    PubMed

    Feria-Velasco, A; Feria-Cuevas, Y; Gutiérrez-Padilla, R

    1995-01-01

    Monosodium L-glutamate (MSG) when administered intraperitoneally (i.p.) to rodents induces convulsions and has been used as a model to study various aspects of status epilepticus of multifocal origin. There are circadian variations of susceptibility to convulsions induced by various factors in some animal species. The aim of this work was to learn whether the convulsive effect of MSG in rats would vary when the drug is given at different times of the day. Three subgroups of Wistar rats were given i.p. 5 mg/g MSG at 07:00, 15:00 and 23:00 h, whereas two groups of rats divided into three subgroups of five animals each were used as controls, also being injected at 07:00, 15:00 and 23:00 h. One group was injected with NaCI solution, equimolar to that of MSG (eqNaCI); the other was injected with physiological saline solution (PSS) in proportional volumes to those of the experimental group. Motor behavior was recorded for 4 h following injections in the three groups of animals. Neither signs of brain hyperexcitability, nor convulsions appeared in animals injected with PSS or eqNaCl. With MSG, no variations were seen in the latency period when data from the three subgroups studied were compared among them. Duration of convulsive period when rats were injected at 07:00 h was shorter than that seen at 15:00 and 23:00 h. No significant variations were seen in total number of convulsive episodes in the three subgroups, while the number of seizures per hour and their intensity were significantly greater when animals were injected at 07:00 h than those seen when rats were studied at 15:00 and 23:00 h. Nearly 70% of animals injected at 07:00 h died in status epilepticus, whereas no deaths were recorded in animals injected at 15:00 and 23:00 h. Results could be explained in terms of variations of physiological processes at both the brain and extracerebral tissues involved in MSG metabolism and cerebral excitability, related to circadian rhythms. PMID:8845636

  15. Spatial variations of effective elastic thickness of the Lithosphere in the Southeast Asia regions

    NASA Astrophysics Data System (ADS)

    Shi, Xiaobin; Kirby, Jon; Yu, Chuanhai; Swain, Chris; Zhao, Junfeng

    2016-04-01

    The effective elastic thickness Te corresponds to the thickness of an idealized elastic beam that would bend similarly to the actual lithosphere under the same applied loads, and could provide important insight into rheology and state of stress. Thus, it is helpful to improve our understanding of the relationship between tectonic styles, distribution of earthquakes and lithospheric rheology in various tectonic settings. The Southeast Asia, located in the southeastern part of the Eurasian Plate, comprises a complex collage of continental fragments, volcanic arcs, and suture zones and marginal oceanic basins, and is surrounded by tectonically active margins which exhibit intense seismicity and volcanism. The Cenozoic southeastward extrusion of the rigid Indochina Block due to the Indo-Asian collision resulted in the drastic surface deformation in the western area. Therefore, a high resolution spatial variation map of Te might be a useful tool for the complex Southeast Asia area to examine the relationships between surface deformation, earthquakes, lithospheric structure and mantle dynamics. In this study, we present a high-resolution map of spatial variations of Te in the Southeast Asia area using the wavelet method, which convolves a range of scaled wavelets with the two data sets of Bouguer gravity anomaly and topography. The topography and bathymetry grid data was extracted from the GEBCO_08 Grid of GEBCO digital atlas. The pattern of Te variations agrees well with the tectonic provinces in the study area. On the whole, low lithosphere strength characterizes the oceanic basins, such as the South China Sea, the Banda sea area, the Celebes Sea, the Sulu Sea and the Andaman Sea. Unlike the oceanic basins, the continental fragments show a complex pattern of Te variations. The Khorat plateau and its adjacent area show strong lithosphere characteristics with a Te range of 20-50 km, suggesting that the Khorat plateau is the strong core of the Indochina Block. The West

  16. Effects of climatic variation on field metabolism and water relations of desert tortoises

    USGS Publications Warehouse

    Henen, B.T.; Peterson, C.C.; Wallis, I.R.; Berry, K.H.; Nagy, K.A.

    1998-01-01

    We used the doubly labeled water method to measure the field metabolic rates (FMRs, in kJ kg-1 day-1) and water flux rates (WIRs, in ml H2O kg-1 day-1) of adult desert tortoises (Gopherus agassizii) in three parts of the Mojave Desert in California over a 3.5-year period, in order to develop insights into the physiological responses of this threatened species to climate variation among sites and years. FMR, WIR, and the water economy index (WEI, in ml H2O kJ-1, an indicator of drinking of free water) differed extensively among seasons, among study sites, between sexes, and among years. In high-rainfall years, males had higher FMRs than females. Average daily rates of energy and water use by desert tortoises were extraordinarily variable: 28-fold differences in FMR and 237-fold differences in WIR were measured. Some of this variation was due to seasonal conditions, with rates being low during cold winter months and higher in the warm seasons. However, much of the variation was due to responses to year-to-year variation in rainfall. Annual spring peaks in FMR and WIR were higher in wet years than in drought years. Site differences in seasonal patterns were apparently due to geographic differences in rainfall patterns (more summer rain at eastern Mojave sites). In spring 1992, during an El Nino (ENSO) event, the WEI was greater than the maximal value obtainable from consuming succulent vegetation, indicating copious drinking of rainwater at that time. The physiological and behavioral flexibility of desert tortoises, evident in individuals living at all three study sites, appears central to their ability to survive droughts and benefit from periods of resource abundance. The strong effects of the El Nino (ENSO) weather pattern on tortoise physiology, reproduction, and survival elucidated in this and other studies suggest that local manifestations of global climate events could have a long-term influence on the tortoise populations in the Mojave Desert.

  17. Effective Elastic Thickness Variations Along the Andean Margin and Their Relationship to Subduction Geometry

    NASA Astrophysics Data System (ADS)

    Perez-Gussinye, M.; Lowry, A. R.; Phipps Morgan, J.; Tassara, A.

    2007-12-01

    We present a new map of spatial variations in effective elastic thickness, Te, along the Andes, estimated using Bouguer coherence. The Te variations reflect interactions between subducting slab and pre-existing terrane structure. In the forearc, conductive cooling of the continent by the subducting slab exerts primary control on rigidity, resulting in Te that is highest (~ 40 km) where the oceanic lithosphere is oldest and coldest (~ 20° S). In the central Andes, Te is relatively low (~ 20 km) along the volcanic chain, the Altiplano and Puna plateaus. We interpret this weakening to reflect a high geothermal gradient maintained by advective magmatic processes, a shallow and hot asthenosphere, and a very weak lower crust throughout this region. East of the plateaus, high Te delineates underthrusting of the Brazilian shield. North and south of the plateaus, areas experiencing flat subduction are characterized by high Te, high shear wave velocity, thick thermal boundary layer and low heat flow, indicating that continental lithosphere there is thicker, colder and stronger. Based on these relationships we suggest that variations in slab dip along the margin relate to variations in structure of the continental lithosphere. In particular, we propose that upper plate structure influences the width and viscosity of the asthenospheric wedge, which control the suction moment responsible for the subduction angle at depths ~ 70--100 km. When oceanic lithosphere subducts beneath thin continental lithosphere, the low viscosity asthenosphere allows the slab to detach from the continent and sink into the mantle at normal angles. However, when oceanic lithosphere subducts near or beneath thick and strong continental lithosphere, the asthenospheric wedge narrows and corner flow drags high viscosity mantle from the base of the thick (> 150 km), cold continent into the wedge. Suction forces increase both with narrowing of the wedge and with increasing viscosity. We estimate the

  18. Effective elastic thickness variations along the Andean margin and their relationship to subduction geometry

    NASA Astrophysics Data System (ADS)

    PéRez-Gussinyé, M.; Lowry, A. R.; Phipps Morgan, J.; Tassara, A.

    2008-02-01

    We present a new map of the spatial variations in effective elastic thickness, Te, along the Andes estimated using Bouguer coherence. The Te variations reflect interactions between subducting slab and preexisting terrane structure. In the forearc, conductive cooling of the continent by the subducting slab exerts primary control on rigidity, resulting in Te that is highest (˜40 km) where the oceanic lithosphere is oldest and coldest (˜20°S). In the central Andes, Te is relatively low (˜20 km) along the volcanic chain and the Altiplano and Puna plateaus. We interpret this weakening to reflect a high geothermal gradient maintained by advective magmatic processes, a shallow and hot asthenosphere, and a very weak lower crust throughout this region. East of the plateaus, high Te delineates underthrusting of the Brazilian shield. Finally, north and south of the plateaus, flat subduction areas are characterized by high Te, high shear wave velocity, thick thermal lithosphere, and low heat flow, indicating that continental lithosphere there is thicker, colder, and stronger. On the basis of these relationships we suggest that variations in slab dip along the margin relate to variations in structure of the continental lithosphere. In particular, we propose that upper plate structure influences the width and viscosity of the asthenospheric wedge, which control the suction moment responsible for the subduction angle at depths ≥70-100 km. For example, when oceanic lithosphere subducts beneath thin continental lithosphere, the low-viscosity asthenosphere allows the slab to detach from the continent and sink into the mantle at normal angles. However, when oceanic lithosphere subducts close or beneath thick and strong continental lithosphere, the asthenospheric wedge narrows and corner flow drags high-viscosity mantle from the base of the thick (>150 km), cold continent into the wedge. Suction forces increase with both narrowing of the wedge and its increasing viscosity. We

  19. Anatomical Brain Images Alone Can Accurately Diagnose Chronic Neuropsychiatric Illnesses

    PubMed Central

    Bansal, Ravi; Staib, Lawrence H.; Laine, Andrew F.; Hao, Xuejun; Xu, Dongrong; Liu, Jun; Weissman, Myrna; Peterson, Bradley S.

    2012-01-01

    Objective Diagnoses using imaging-based measures alone offer the hope of improving the accuracy of clinical diagnosis, thereby reducing the costs associated with incorrect treatments. Previous attempts to use brain imaging for diagnosis, however, have had only limited success in diagnosing patients who are independent of the samples used to derive the diagnostic algorithms. We aimed to develop a classification algorithm that can accurately diagnose chronic, well-characterized neuropsychiatric illness in single individuals, given the availability of sufficiently precise delineations of brain regions across several neural systems in anatomical MR images of the brain. Methods We have developed an automated method to diagnose individuals as having one of various neuropsychiatric illnesses using only anatomical MRI scans. The method employs a semi-supervised learning algorithm that discovers natural groupings of brains based on the spatial patterns of variation in the morphology of the cerebral cortex and other brain regions. We used split-half and leave-one-out cross-validation analyses in large MRI datasets to assess the reproducibility and diagnostic accuracy of those groupings. Results In MRI datasets from persons with Attention-Deficit/Hyperactivity Disorder, Schizophrenia, Tourette Syndrome, Bipolar Disorder, or persons at high or low familial risk for Major Depressive Disorder, our method discriminated with high specificity and nearly perfect sensitivity the brains of persons who had one specific neuropsychiatric disorder from the brains of healthy participants and the brains of persons who had a different neuropsychiatric disorder. Conclusions Although the classification algorithm presupposes the availability of precisely delineated brain regions, our findings suggest that patterns of morphological variation across brain surfaces, extracted from MRI scans alone, can successfully diagnose the presence of chronic neuropsychiatric disorders. Extensions of these

  20. Clinical repercussions of Martin-Gruber anastomosis: anatomical study☆

    PubMed Central

    Cavalheiro, Cristina Schmitt; Filho, Mauro Razuk; Pedro, Gabriel; Caetano, Maurício Ferreira; Vieira, Luiz Angelo; Caetano, Edie Benedito

    2016-01-01

    Objective The main objective of this study was to describe Martin-Gruber anastomosis anatomically and to recognize its clinical repercussions. Method 100 forearms of 50 adult cadavers were dissected in an anatomy laboratory. The dissection was performed by means of a midline incision along the entire forearm and the lower third of the upper arm. Two flaps including skin and subcutaneous tissue were folded back on the radial and ulnar sides, respectively. Results Nerve communication between the median and ulnar nerves in the forearm (Martin-Gruber anastomosis) was found in 27 forearms. The anastomosis was classified into six types: type I: anastomosis between the anterior interosseous nerve and the ulnar nerve (n = 9); type II: anastomosis between the anterior interosseous nerve and the ulnar nerve at two points (double anastomosis) (n = 2); type III: anastomosis between the median nerve and the ulnar nerve (n = 4); type IV: anastomosis between branches of the median nerve and ulnar nerve heading toward the flexor digitorum profundus muscle of the fingers; these fascicles form a loop with distal convexity (n = 5); type V: intramuscular anastomosis (n = 5); and type VI: anastomosis between a branch of the median nerve to the flexor digitorum superficialis muscle and the ulnar nerve (n = 2). Conclusion Knowledge of the anatomical variations relating to the innervation of the hand has great importance, especially with regard to physical examination, diagnosis, prognosis and surgical treatment. If these variations are not given due regard, errors and other consequences will be inevitable. PMID:27069892

  1. Juvenile survival in a tropical population of roseate terns: Interannual variation and effect of tick parasitism

    USGS Publications Warehouse

    Monticelli, D.; Ramos, J.A.; Hines, J.E.; Nichols, J.D.; Spendelow, J.A.

    2008-01-01

    Many demographic studies on long-lived seabirds have focused on the estimation of adult survival, but much less is known about survival during the early years of life, especially in tropical species. We report analyses of a capture?recapture dataset of 685 roseate terns ringed as fledglings and adults between 1998 and 2005 on Aride Island, Seychelles, and recaptured/resighted at the same colony site over a 5 yr (2002 to 2006) period. A multistate model was used to estimate survival for different age classes, including juvenile (first-year) birds returning as non-breeding prospectors. The effect of infestation by parasites (ticks) on survival was also examined. Overall, the estimated return of first-year individuals to the natal colony was very variable, ranging from 2 to 22%. Conditioned on survival, the probability of returning from Age 2 yr onwards increased to 70%. Survival rates were best modeled as time-specific, with estimates varying from 0.02 to 1.00 (mean 0.69) in first-year birds with a marked negative effect of tick infestation. In older birds (minimum age of 2 yr), the annual estimates fell between 0.69 and 0.86 (mean 0.77). Using a components of variance approach for estimation of year-to-year variation, we found high temporal variability for first-year individuals (coefficient of variation [CV] = 65%) compared to much less variation in the survival rate of older birds (CV = 9%). These findings agree with the life-history prediction that demographic rates of juveniles are usually lower and more variable than those of older individuals. Our results are also consistent with the predicted negative effect of tick parasitism on juvenile survival. Compared with data from other roseate tern populations, survival over the first 2 yr (Age 0 to 2 yr) was 18 to 40% higher in this study, suggesting that a high `young? survival rate may be an important demographic trait in this tropical population to compensate for the low annual reproductive success. Our data show

  2. Juvenile survival in a tropical population of roseate terns: Interannual variation and effect of tick parasitism

    USGS Publications Warehouse

    Monticelli, D.; Ramos, J.A.; Hines, J.E.; Nichols, J.D.; Spendelow, J.A.

    2008-01-01

    Many demographic studies on long-lived seabirds have focused on the estimation of adult survival, but much less is known about survival during the early years of life, especially in tropical species. We report analyses of a capture-recapture dataset of 685 roseate terns ringed as fledglings and adults between 1998 and 2005 on Aride Island, Seychelles, and recaptured/resighted at the same colony site over a 5 yr (2002 to 2006) period. A multistate model was used to estimate survival for different age classes, including juvenile (first-year) birds returning as non-breeding prospectors. The effect of infestation by parasites (ticks) on survival was also examined. Overall, the estimated return of first-year individuals to the natal colony was very variable, ranging from 2 to 22%. Conditioned on survival, the probability of returning from Age 2 yr onwards increased to 70%. Survival rates were best modeled as time-specific, with estimates varying from 0.02 to 1.00 (mean 0.69) in first-year birds with a marked negative effect of tick infestation. In older birds (minimum age of 2 yr), the annual estimates fell between 0.69 and 0.86 (mean 0.77). Using a components of variance approach for estimation of year-to-year variation, we found high temporal variability for first-year individuals (coefficient of variation [CV] = 65%) compared to much less variation in the survival rate of older birds (CV = 9 %). These findings agree with the life-history prediction that demographic rates of juveniles are usually lower and more variable than those of older individuals. Our results are also consistent with the predicted negative effect of tick parasitism on juvenile survival. Compared with data from other roseate tern populations, survival over the first 2 yr (Age 0 to 2 yr) was 18 to 40% higher in this study, suggesting that a high 'young' survival rate may be an important demographic trait in this tropical population to compensate for the low annual reproductive success. Our data

  3. Historical evolution of anatomical terminology from ancient to modern.

    PubMed

    Sakai, Tatsuo

    2007-06-01

    The historical development of anatomical terminology from the ancient to the modern can be divided into five stages. The initial stage is represented by the oldest extant anatomical treatises by Galen of Pergamon in the Roman Empire. The anatomical descriptions by Galen utilized only a limited number of anatomical terms, which were essentially colloquial words in the Greek of this period. In the second stage, Vesalius in the early 16th century described the anatomical structures in his Fabrica with the help of detailed magnificent illustrations. He coined substantially no anatomical terms, but devised a system that distinguished anatomical structures with ordinal numbers. The third stage of development in the late 16th century was marked by innovation of a large number of specific anatomical terms especially for the muscles, vessels and nerves. The main figures at this stage were Sylvius in Paris and Bauhin in Basel. In the fourth stage between Bauhin and the international anatomical terminology, many anatomical textbooks were written mainly in Latin in the 17th century, and in modern languages in the 18th and 19th centuries. Anatomical terms for the same structure were differently expressed by different authors. The last stage began at the end of the 19th century, when the first international anatomical terminology in Latin was published as Nomina anatomica. The anatomical terminology was revised repeatedly until the current Terminologia anatomica both in Latin and English. PMID:17585563

  4. Anatomical calibration for wearable motion capture systems: Video calibrated anatomical system technique.

    PubMed

    Bisi, Maria Cristina; Stagni, Rita; Caroselli, Alessio; Cappello, Angelo

    2015-08-01

    Inertial sensors are becoming widely used for the assessment of human movement in both clinical and research applications, thanks to their usability out of the laboratory. This work aims to propose a method for calibrating anatomical landmark position in the wearable sensor reference frame with an ease to use, portable and low cost device. An off-the-shelf camera, a stick and a pattern, attached to the inertial sensor, compose the device. The proposed technique is referred to as video Calibrated Anatomical System Technique (vCAST). The absolute orientation of a synthetic femur was tracked both using the vCAST together with an inertial sensor and using stereo-photogrammetry as reference. Anatomical landmark calibration showed mean absolute error of 0.6±0.5 mm: these errors are smaller than those affecting the in-vivo identification of anatomical landmarks. The roll, pitch and yaw anatomical frame orientations showed root mean square errors close to the accuracy limit of the wearable sensor used (1°), highlighting the reliability of the proposed technique. In conclusion, the present paper proposes and preliminarily verifies the performance of a method (vCAST) for calibrating anatomical landmark position in the wearable sensor reference frame: the technique is low time consuming, highly portable, easy to implement and usable outside laboratory. PMID:26077101

  5. Depressive Symptoms, Anatomical Region, and Clinical Outcomes for Patients Seeking Outpatient Physical Therapy for Musculoskeletal Pain

    PubMed Central

    Coronado, Rogelio A.; Beneciuk, Jason M.; Valencia, Carolina; Werneke, Mark W.; Hart, Dennis L.

    2011-01-01

    Background Clinical guidelines advocate the routine identification of depressive symptoms for patients with pain in the lumbar or cervical spine, but not for other anatomical regions. Objective The purpose of this study was to investigate the prevalence and impact of depressive symptoms for patients with musculoskeletal pain across different anatomical regions. Design This was a prospective, associational study. Methods Demographic, clinical, depressive symptom (Symptom Checklist 90–Revised), and outcome data were collected by self-report from a convenience sample of 8,304 patients. Frequency of severe depressive symptoms was assessed by chi-square analysis for demographic and clinical variables. An analysis of variance examined the influence of depressive symptoms and anatomical region on intake pain intensity and functional status. Separate hierarchical multiple regression models by anatomical region examined the influence of depressive symptoms on clinical outcomes. Results Prevalence of severe depression was higher in women, in industrial and pain clinics, and in patients who reported chronic pain or prior surgery. Lower prevalence rates were found in patients older than 65 years and those who had upper- or lower-extremity pain. Depressive symptoms had a moderate to large effect on pain ratings (Cohen d=0.55–0.87) and a small to large effect on functional status (Cohen d=0.28–0.95). In multivariate analysis, depressive symptoms contributed additional variance to pain intensity and functional status for all anatomical locations, except for discharge values for the cervical region. Conclusions Rates of depressive symptoms varied slightly based on anatomical region of musculoskeletal pain. Depressive symptoms had a consistent detrimental influence on outcomes, except on discharge scores for the cervical anatomical region. Expanding screening recommendations for depressive symptoms to include more anatomical regions may be indicated in physical therapy

  6. Evaluation of predictors for anatomical success in macular hole surgery in Indian population

    PubMed Central

    Kumar, Atul; Gogia, Varun; Kumar, Prakhar; Sehra, Srivats; Gupta, Shikha

    2014-01-01

    Purpose: The aim was to evaluate outcomes and predictors for anatomical success in macular hole (MH) surgery. Materials and Methods: This was a prospective cohort study of patients operated for idiopathic MH with stages II, III or IV. Patients underwent pars plana vitrectomy with internal limiting membrane (ILM) peeling, internal gas tamponade, and postoperative face down positioning. The primary outcome measure was anatomical closure of MH, while secondary outcome measure was postoperative external limiting membrane (ELM) continuity. Effect of MH size, duration of MH, size of ILM peel, type of gas tamponade (SF6 vs. C3F8) and macular hole index (MHI) on anatomical MH closure was also evaluated. Results: Of the 62 eyes operated, anatomical closure of MH was achieved in 55 eyes (88.7%). The median duration of follow-up was 8 months (range: 6–15 months). Mean BVCA improved from 0.94 ± 0.26 at baseline to 0.40 ± 0.23 logMAR at last follow-up (P = 0.01). There was a statistically significant association between size of ILM peel and anatomical closure of MH (P = 0.04). Duration of symptoms, size of MH, type of gas tamponade, MHI had no effect on anatomical closure (P = 0.22, 0.28, 0.40 respectively, Chi-square test). Postoperative continuity of the ELM was significantly associated with a shorter symptom duration (<6 months) before surgery. Conclusion: Acceptable anatomical closure could be attained with the defined technique. Size of ILM peel is a new predictor of anatomical success while symptom duration affects postoperative ELM continuity. PMID:25579358

  7. The Effect of an Experimental Bottleneck upon Quantitative Genetic Variation in the Housefly

    PubMed Central

    Bryant, Edwin H.; McCommas, Steven A.; Combs, Lisa M.

    1986-01-01

    Effects of a population bottleneck (founder-flush cycle) upon quantitative genetic variation of morphometric traits were examined in replicated experimental lines of the housefly founded with one, four or 16 pairs of flies. Heritability and additive genetic variances for eight morphometric traits generally increased as a result of the bottleneck, but the pattern of increase among bottleneck sizes differed among traits. Principal axes of the additive genetic correlation matrix for the control line yielded two suites of traits, one associated with general body size and another set largely independent of body size. In the former set containing five of the traits, additive genetic variance was greatest in the bottleneck size of four pairs, whereas in the latter set of two traits the largest additive genetic variance occurred in the smallest bottleneck size of one pair. One trait exhibited changes in additive genetic variance intermediate between these two major responses. These results were inconsistent with models of additive effects of alleles within loci or of additive effects among loci. An observed decline in viability measures and body size in the bottleneck lines also indicated that there was nonadditivity of allelic effects for these traits. Several possible nonadditive models were explored that increased additive genetic variance as a result of a bottleneck. These included a model with complete dominance, a model with overdominance and a model incorporating multiplicative epistasis. PMID:17246359

  8. The effect of random dopant fluctuation on threshold voltage and drain current variation in junctionless nanotransistors

    NASA Astrophysics Data System (ADS)

    Rezapour, Arash; Rezapour, Pegah

    2015-09-01

    We investigate the effect of dopant random fluctuation on threshold voltage and drain current variation in a two-gate nanoscale transistor. We used a quantum-corrected technology computer aided design simulation to run the simulation (10000 randomizations). With this simulation, we could study the effects of varying the dimensions (length and width), and thicknesses of oxide and dopant factors of a transistor on the threshold voltage and drain current in subthreshold region (off) and overthreshold (on). It was found that in the subthreshold region the variability of the drain current and threshold voltage is relatively fixed while in the overthreshold region the variability of the threshold voltage and drain current decreases remarkably, despite the slight reduction of gate voltage diffusion (compared with that of the subthreshold). These results have been interpreted by using previously reported models for threshold current variability, load displacement, and simple analytical calculations. Scaling analysis shows that the variability of the characteristics of this semiconductor increases as the effects of the short channel increases. Therefore, with a slight increase of length and a reduction of width, oxide thickness, and dopant factor, we could correct the effect of the short channel.

  9. The Effects of Atmospheric Opacity on the Seasonal Variation of Martian Surface Temperature

    NASA Technical Reports Server (NTRS)

    Wilson, R. J.; Smith, M. D.

    2005-01-01

    The daily and seasonal variation of surface temperature is a central element in the description of martian climate. Surface thermal inertia and albedo are critical boundary inputs for simulating surface temperature in Mars general circulation models (MGCMs). Thermal inertia (TI) is also of intrinsic interest as it may be related to regolith properties such as particle size and surface character and so high spatial resolution is desirable. The recent mapping of TI at very high (0.25 deg) spatial resolution was achieved by fitting a thermal model to surface temperature observations obtained over a broad range of several martian years. However, varying atmospheric opacity (dust and water ice clouds) can significantly influence the estimated TI field and this effect was not fully compensated for. Opacity leads to an increase in morning temperature and a decrease in afternoon temperature, thus increasing the apparent thermal inertia.

  10. The Effect of Kinetic Properties on Statistical Variations of Ultrasound Signals Backscattered from Flowing Blood

    NASA Astrophysics Data System (ADS)

    Huang, Chih-Chung; Lin, Yi-Hsun; Wang, Shyh-Hau

    2009-02-01

    Yet very little is known about the effect of “black hole” (BH) phenomenon on backscattering signal statistics under the laminar flow. To further explore this issue, measurements were performed from the porcine blood (with hematocrits of 20 and 50%) circulating in a mock flow loop under various steady flows at velocities ranged from 15 to 122 mm/s using a 10 MHz ultrasonic transducer. Results showed that the BH was apparent for the 50% blood flowing at a low velocity. The BH tended to be decreased with the increase of flow velocity and that it was hardly observed from the 20% blood. The probability density function of signals backscattered from blood tended to distribute as pre-Rayleigh statistics and the Nakagami parameter was less than 1. The spatial distribution of red cell aggregation in the flow tube is a predominant factor leading to statistical variations of ultrasonic backscattering in the flowing blood.

  11. Effect of emitter parameter variation on the performance of heteroepitaxial indium phosphide solar cells

    NASA Technical Reports Server (NTRS)

    Jain, R. K.; Flood, D. J.

    1990-01-01

    Metalorganic chemical-vapor-deposited heteroepitaxial indium phosphide (InP) solar cell experimental results were simulated by using a PC-1D computer model. The effect of emitter parameter variation on the performance of n(+)/p/p(+) heteroepitaxial InP/GaAs solar cell was presented. The thinner and lighter doped emitters were observed to offer higher cell efficiencies. The influence of emitter thickness and minority carrier diffusion length on the cell efficiency with respect to dislocation density was studied. Heteroepitaxial cells with efficiencies similar to present day homojunction InP efficiencies (greaater than 16 percent AM0) were shown to be attainable if a dislocation density lower than 10(exp 6)/sq cm could be achieved. A realistic optimized design study yielded InP solar cells of over 22 percent AM0 efficiency at 25 C.

  12. Effect of emitter parameter variation on the performance of heteroepitaxial indium phosphide solar cells

    NASA Technical Reports Server (NTRS)

    Jain, Raj K.; Flood, Dennis J.

    1990-01-01

    Metallorganic chemical-vapor-deposited heteroepitaxial indium phosphide (InP) solar cell experimental results were simulated by using a PC-1D computer model. The effect of emitter parameter variation on the performance of n(+)/p/p(+) heteroepitaxial InP/GaAs solar cell was presented. The thinner and lighter doped emitters were observed to offer higher cell efficiencies. The influence of emitter thickness and minority carrier diffusion length on the cell efficiency with respect to dislocation density was studied. Heteroepitaxial cells with efficiencies similar to present day homojunction InP efficiencies (greater than 16 percent AMO) were shown to be attainable if a dislocation density lower than 10(exp 6)/sq cm could be achieved. A realistic optimized design study yielded InP solar cells of over 22 percent AMO efficiency at 25 C.

  13. Sex Variations in Youth Anxiety Symptoms: Effects of Pubertal Development and Gender Role Orientation

    PubMed Central

    Carter, Rona; Silverman, Wendy K.; Jaccard, James

    2011-01-01

    This study evaluated whether pubertal development and gender role orientation (i.e., masculinity and femininity) can partially explain sex variations in youth anxiety symptoms among clinic referred anxious youth (N = 175; ages 9-13 years; 74% Hispanic; 48% female). Using youth and parent ratings of youth anxiety symptoms, structural equation modeling results indicated that youth who reported being more advanced in their pubertal development reported high levels of femininity and anxiety symptoms. Youth who reported high levels of masculinity had low levels of anxiety symptoms as reported by both youths and parents. The estimated effects of pubertal development, femininity, and masculinity on youth and parent ratings of youth anxiety symptoms were not significantly moderated by biological sex. Pubertal development and gender role orientation appear to be important in explaining levels of youth anxiety symptoms among clinic referred anxious youth. PMID:21916691

  14. Upstream pressure variations associated with the bow shock and their effects on the magnetosphere

    NASA Technical Reports Server (NTRS)

    Fairfield, D. H.; Baumjohann, W.; Paschmann, G.; Luehr, H.; Sibeck, D. G.

    1990-01-01

    The AMPTE IRM solar wind data are analyzed to determine the relationship between upstream pressure fluctuations and magnetospheric perturbations. It is argued that the upstream pressure variations are not inherent in the solar wind but rather are associated with the bow shock. This conclusion follows from the fact that the upstream field strength and density associated with perturbations are highly correlated with each other, while they tend to be anticorrelated in the undisturbed solar wind, and that the upstream perturbations occur within the foreshock or at its boundary. The results imply a mode of interaction between the solar wind upstream and the magnetosphere whereby density changes produced in the foreshock subsequently convect through the bow shock and impinge on the magnetosphere. Upstream pressure perturbations should create significant effects on the magnetopause and at the foot of nearby field lines that lead to the polar cusp ionosphere.

  15. Geographic variation in marine invasions among large estuaries: effects of ships and time.

    PubMed

    Ruiz, Gregory M; Fofonoff, Paul W; Ashton, Gail; Minton, Mark S; Miller, A Whitman

    2013-03-01

    Coastal regions exhibit strong geographic patterns of nonnative species richness. Most invasions in marine ecosystems are known from bays and estuaries, where ship-mediated transfers (on hulls or in ballasted materials) have been a dominant vector of species introductions. Conspicuous spatial differences in nonnative species richness exist among bays, but the quantitative relationship between invasion magnitude and shipping activity across sites is largely unexplored. Using data on marine invasions (for invertebrates and algae) and commercial shipping across 16 large bays in the United States, we estimated (1) geographic variation in nonnative species richness attributed to ships, controlling for effects of salinity and other vectors, (2) changes through time in geographic variation of these ship-mediated invasions, and (3) effects of commercial ship traffic and ballast water discharge magnitude on nonnative species richness. For all nonnative species together (regardless of vector, salinity, or time period), species richness differed among U.S. coasts, being significantly greater for Pacific Coast bays than Atlantic or Gulf Coast bays. This difference also existed when considering only species attributed to shipping (or ballast water), controlling for time and salinity. Variation in nonnative species richness among Pacific Coast bays was strongly affected by these same criteria. San Francisco Bay, California, had over 200 documented nonnative species, more than twice that reported for other bays, but many species were associated with other (non-shipping) vectors or the extensive low-salinity habitats (unavailable in some bays). When considering only ship- or ballast-mediated introductions in high-salinity waters, the rate of newly detected invasions in San Francisco Bay has converged increasingly through time on that for other Pacific Coast bays, appearing no different since 1982. Considering all 16 bays together, there was no relationship between either (1

  16. Daily variation and effects of ambient light and circadian factors on the human light reflex.

    PubMed

    Fosnaugh, J S; Bunker, E B; Pickworth, W B

    1992-09-01

    Measures of pupillary size and the dynamic light reflex are safe and noninvasive methods to quantify and characterize the mechanism and site of drug action. The effects of variations in ambient light and time of day on pupillary measures were determined. In dark adapted volunteers (n = 13), ambient light was incrementally increased at < 0.1, 4, 40, 100 and 200 foot-candle (ftcd). Subjects adjusted to each light level for 1 min before the light reflex was elicited. Replicate measures were collected with the contralateral eye open and covered with an opaque patch. Data were collected every 3 h between 6 a.m. and 9 p.m. The prestimulus diameter of the dark adapted pupil averaged 6.4 mm at < 0.1 ftcd and 2.3 mm at 200 ftcd. Constriction amplitude decreased with increases in ambient light from 2.1 mm (< 0.1 ftcd) to 0.2 mm (200 ftcd) while constriction and dilatation velocities decreased from 7.7 to 2.8 mm/sec and 4.3 to 2.8 mm/sec, respectively. Time of day effects were small but statistically significant and the interaction of ambient light and time of recording suggests the pupil is differentially sensitive to ambient and phasic light stimuli over the course of the day. A patch over the contralateral eye increased pupil size and velocities of the light reflex. In a second study, 10 volunteers were tested twice a day at 4 and 80 ftcd for four days. While there was wide between subject variability, the within subject differences were small. Such baseline data may be useful in describing the normal variations in these increasingly popular indices of drug action. PMID:1287379

  17. A limit on the variation of the speed of light arising from quantum gravity effects.

    PubMed

    Abdo, A A; Ackermann, M; Ajello, M; Asano, K; Atwood, W B; Axelsson, M; Baldini, L; Ballet, J; Barbiellini, G; Baring, M G; Bastieri, D; Bechtol, K; Bellazzini, R; Berenji, B; Bhat, P N; Bissaldi, E; Bloom, E D; Bonamente, E; Bonnell, J; Borgland, A W; Bouvier, A; Bregeon, J; Brez, A; Briggs, M S; Brigida, M; Bruel, P; Burgess, J M; Burnett, T H; Caliandro, G A; Cameron, R A; Caraveo, P A; Casandjian, J M; Cecchi, C; Celik, O; Chaplin, V; Charles, E; Cheung, C C; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; Cominsky, L R; Connaughton, V; Conrad, J; Cutini, S; Dermer, C D; de Angelis, A; de Palma, F; Digel, S W; Dingus, B L; do Couto E Silva, E; Drell, P S; Dubois, R; Dumora, D; Farnier, C; Favuzzi, C; Fegan, S J; Finke, J; Fishman, G; Focke, W B; Foschini, L; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Gibby, L; Giebels, B; Giglietto, N; Giordano, F; Glanzman, T; Godfrey, G; Granot, J; Greiner, J; Grenier, I A; Grondin, M-H; Grove, J E; Grupe, D; Guillemot, L; Guiriec, S; Hanabata, Y; Harding, A K; Hayashida, M; Hays, E; Hoversten, E A; Hughes, R E; Jóhannesson, G; Johnson, A S; Johnson, R P; Johnson, W N; Kamae, T; Katagiri, H; Kataoka, J; Kawai, N; Kerr, M; Kippen, R M; Knödlseder, J; Kocevski, D; Kouveliotou, C; Kuehn, F; Kuss, M; Lande, J; Latronico, L; Lemoine-Goumard, M; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Madejski, G M; Makeev, A; Mazziotta, M N; McBreen, S; McEnery, J E; McGlynn, S; Mészáros, P; Meurer, C; Michelson, P F; Mitthumsiri, W; Mizuno, T; Moiseev, A A; Monte, C; Monzani, M E; Moretti, E; Morselli, A; Moskalenko, I V; Murgia, S; Nakamori, T; Nolan, P L; Norris, J P; Nuss, E; Ohno, M; Ohsugi, T; Omodei, N; Orlando, E; Ormes, J F; Ozaki, M; Paciesas, W S; Paneque, D; Panetta, J H; Parent, D; Pelassa, V; Pepe, M; Pesce-Rollins, M; Petrosian, V; Piron, F; Porter, T A; Preece, R; Rainò, S; Ramirez-Ruiz, E; Rando, R; Razzano, M; Razzaque, S; Reimer, A; Reimer, O; Reposeur, T; Ritz, S; Rochester, L S; Rodriguez, A Y; Roth, M; Ryde, F; Sadrozinski, H F-W; Sanchez, D; Sander, A; Saz Parkinson, P M; Scargle, J D; Schalk, T L; Sgrò, C; Siskind, E J; Smith, D A; Smith, P D; Spandre, G; Spinelli, P; Stamatikos, M; Stecker, F W; Strickman, M S; Suson, D J; Tajima, H; Takahashi, H; Takahashi, T; Tanaka, T; Thayer, J B; Thayer, J G; Thompson, D J; Tibaldo, L; Toma, K; Torres, D F; Tosti, G; Troja, E; Uchiyama, Y; Uehara, T; Usher, T L; van der Horst, A J; Vasileiou, V; Vilchez, N; Vitale, V; von Kienlin, A; Waite, A P; Wang, P; Wilson-Hodge, C; Winer, B L; Wood, K S; Wu, X F; Yamazaki, R; Ylinen, T; Ziegler, M

    2009-11-19

    A cornerstone of Einstein's special relativity is Lorentz invariance-the postulate that all observers measure exactly the same speed of light in vacuum, independent of photon-energy. While special relativity assumes that there is no fundamental length-scale associated with such invariance, there is a fundamental scale (the Planck scale, l(Planck) approximately 1.62 x 10(-33) cm or E(Planck) = M(Planck)c(2) approximately 1.22 x 10(19) GeV), at which quantum effects are expected to strongly affect the nature of space-time. There is great interest in the (not yet validated) idea that Lorentz invariance might break near the Planck scale. A key test of such violation of Lorentz invariance is a possible variation of photon speed with energy. Even a tiny variation in photon speed, when accumulated over cosmological light-travel times, may be revealed by observing sharp features in gamma-ray burst (GRB) light-curves. Here we report the detection of emission up to approximately 31 GeV from the distant and short GRB 090510. We find no evidence for the violation of Lorentz invariance, and place a lower limit of 1.2E(Planck) on the scale of a linear energy dependence (or an inverse wavelength dependence), subject to reasonable assumptions about the emission (equivalently we have an upper limit of l(Planck)/1.2 on the length scale of the effect). Our results disfavour quantum-gravity theories in which the quantum nature of space-time on a very small scale linearly alters the speed of light. PMID:19865083

  18. Integrating anatomical pathology to the healthcare enterprise.

    PubMed

    Daniel-Le Bozec, Christel; Henin, Dominique; Fabiani, Bettina; Bourquard, Karima; Ouagne, David; Degoulet, Patrice; Jaulent, Marie-Christine

    2006-01-01

    For medical decisions, healthcare professionals need that all required information is both correct and easily available. We address the issue of integrating anatomical pathology department to the healthcare enterprise. The pathology workflow from order to report, including specimen process and image acquisition was modeled. Corresponding integration profiles were addressed by expansion of the IHE (Integrating the Healthcare Enterprise) initiative. Implementation using respectively DICOM Structured Report (SR) and DICOM Slide-Coordinate Microscopy (SM) was tested. The two main integration profiles--pathology general workflow and pathology image workflow--rely on 13 transactions based on HL7 or DICOM standard. We propose a model of the case in anatomical pathology and of other information entities (orders, image folders and reports) and real-world objects (specimen, tissue samples, slides, etc). Cases representation in XML schemas, based on DICOM specification, allows producing DICOM image files and reports to be stored into a PACS (Picture Archiving and Communication System. PMID:17108550

  19. The Computerized Anatomical Man (CAM) model

    NASA Technical Reports Server (NTRS)

    Billings, M. P.; Yucker, W. R.

    1973-01-01

    A computerized anatomical man (CAM) model, representing the most detailed and anatomically correct geometrical model of the human body yet prepared, has been developed for use in analyzing radiation dose distribution in man. This model of a 50-percentile standing USAF man comprises some 1100 unique geometric surfaces and some 2450 solid regions. Internal body geometry such as organs, voids, bones, and bone marrow are explicitly modeled. A computer program called CAMERA has also been developed for performing analyses with the model. Such analyses include tracing rays through the CAM geometry, placing results on magnetic tape in various forms, collapsing areal density data from ray tracing information to areal density distributions, preparing cross section views, etc. Numerous computer drawn cross sections through the CAM model are presented.

  20. Endoscopic Ankle Lateral Ligament Graft Anatomic Reconstruction.

    PubMed

    Michels, Frederick; Cordier, Guillaume; Guillo, Stéphane; Stockmans, Filip

    2016-09-01

    Chronic instability is a common complication of lateral ankle sprains. If nonoperative treatment fails, a surgical repair or reconstruction may be indicated. Today, endoscopic techniques to treat ankle instability are becoming more popular. This article describes an endoscopic technique, using a step-by-step approach, to reconstruct the ATFL and CFL with a gracilis graft. The endoscopic technique is reproducible and safe with regard to the surrounding anatomic structures. Short and midterm results confirm the benefits of this technique. PMID:27524711

  1. Evolution of the anatomical theatre in Padova.

    PubMed

    Macchi, Veronica; Porzionato, Andrea; Stecco, Carla; De Caro, Raffaele

    2014-01-01

    The anatomical theatre played a pivotal role in the evolution of medical education, allowing students to directly observe and participate in the process of dissection. Due to the increase of training programs in clinical anatomy, the Institute of Human Anatomy at the University of Padova has renovated its dissecting room. The main guidelines in planning a new anatomical theatre included: (1), the placement of the teacher and students on the same level in a horizontal anatomical theatre where it is possible to see (theatre) and to perform (dissecting room); (2), in the past, dissection activities were concentrated at the center of the theatre, while in the new anatomical theatre, such activities have been moved to the periphery through projection on surrounding screens-thus, students occupy the center of the theatre between the demonstration table, where the dissection can be seen in real time, and the wall screens, where particular aspects are magnified; (3), three groups of tables are placed with one in front with two lateral flanking tables in regards to the demonstration table, in a semicircular arrangement, and not attached to the floor, which makes the room multifunctional for surgical education, medical students and physician's continued professional development courses; (4), a learning station to introduce the students to the subject of the laboratory; (5), cooperation between anatomists and architects in order to combine the practical needs of a dissection laboratory with new technologies; (6), involvement of the students, representing the clients' needs; and (7), creation of a dissecting room of wide measurements with large windows, since a well-illuminated space could reduce the potentially negative psychological impact of the dissection laboratory on student morale. PMID:24706523

  2. Spatiotemporal variation in the microclimatic edge effect between wetland and farmland

    NASA Astrophysics Data System (ADS)

    Liao, Xiaoyu; Liu, Zhaoli; Wang, Yiyong; Jin, Jiming

    2013-07-01

    The creation of wetland edges associated with anthropogenic fragmentation is common in wetland landscapes and brings about a unique microclimatic change that affects adjacent farmland. However, microclimatic edge effects within this kind of landscape are not well quantified. Thus, using a study site located in the northeastern Sanjiang National Nature Reserve, China, we investigated the spatiotemporal variations in the microclimatic variables of the surface layer across the wetland-farmland edge. Air temperature and relative humidity data were collected continuously along a horizontal transect at four different heights over different periods, and the relative humidity was converted to specific humidity. Sigmoid models were used to fit the horizontal gradients of microclimatic edge effects. Then, based on the parameters in the fitted models, the characteristics of the edge effects were quantified with two indices, the magnitude of edge effect (MEE) and the spatial range of edge effect (REE). Under a light wind condition, the microclimatic features across the edge generally presented sigmoid ecological gradients in the horizontal direction, with unique spatial and temporal patterns: (1) In a normal year, wetland patches cooled and moistened the adjacent farmlands during the daytime and had a warming-moistening effect during the nighttime. (2) Vertically, the absolute MEE value of the microclimatic variables decreased, but the REE increased with increasing height. (3) The MEE and REE for air temperature and specific humidity varied with the time of day, both shifting at dawn and dusk when the gradients were absent. (4) At the interannual scale, when compared to the farmland, the wetland was cooler at night in a dry year but warmer in a normal year. The detection of spatiotemporal microclimatic patterns in the wetland-farmland edge zone may enable further understanding of how wetland degradation affects adjacent farmland ecology under human disturbance and promote

  3. Engineering anatomically shaped human bone grafts

    PubMed Central

    Grayson, Warren L.; Fröhlich, Mirjam; Yeager, Keith; Bhumiratana, Sarindr; Chan, M. Ete; Cannizzaro, Christopher; Wan, Leo Q.; Liu, X. Sherry; Guo, X. Edward; Vunjak-Novakovic, Gordana

    2009-01-01

    The ability to engineer anatomically correct pieces of viable and functional human bone would have tremendous potential for bone reconstructions after congenital defects, cancer resections, and trauma. We report that clinically sized, anatomically shaped, viable human bone grafts can be engineered by using human mesenchymal stem cells (hMSCs) and a “biomimetic” scaffold-bioreactor system. We selected the temporomandibular joint (TMJ) condylar bone as our tissue model, because of its clinical importance and the challenges associated with its complex shape. Anatomically shaped scaffolds were generated from fully decellularized trabecular bone by using digitized clinical images, seeded with hMSCs, and cultured with interstitial flow of culture medium. A bioreactor with a chamber in the exact shape of a human TMJ was designed for controllable perfusion throughout the engineered construct. By 5 weeks of cultivation, tissue growth was evidenced by the formation of confluent layers of lamellar bone (by scanning electron microscopy), markedly increased volume of mineralized matrix (by quantitative microcomputer tomography), and the formation of osteoids (histologically). Within bone grafts of this size and complexity cells were fully viable at a physiologic density, likely an important factor of graft function. Moreover, the density and architecture of bone matrix correlated with the intensity and pattern of the interstitial flow, as determined in experimental and modeling studies. This approach has potential to overcome a critical hurdle—in vitro cultivation of viable bone grafts of complex geometries—to provide patient-specific bone grafts for craniofacial and orthopedic reconstructions. PMID:19820164

  4. Device for removing foreign objects from anatomic organs

    NASA Technical Reports Server (NTRS)

    Angulo, Earl D. (Inventor)

    1992-01-01

    A device is disclosed for removing foreign objects from anatomic organs such as the ear canal or throat. It has a housing shaped like a flashlight, an electrical power source such as a battery or AC power from a wall socket, and a tip extending from the housing. The tip has at least one wire loop made from a shape-memory-effect alloy, such as Nitinol, switchably connected to the electrical power source such that when electric current flows through the wire loop the wire loop heats up and returns to a previously programmed shape such as a curet or tweezers so as to facilitate removal of the foreign object.

  5. Solar Sail Topology Variations Due to On-Orbit Thermal Effects

    NASA Technical Reports Server (NTRS)

    Banik, Jeremy A.; Lively, Peter S.; Taleghani, Barmac K.; Jenkins, Chrostopher H.

    2006-01-01

    The objective of this research was to predict the influence of non-uniform temperature distribution on solar sail topology and the effect of such topology variations on sail performance (thrust, torque). Specifically considered were the thermal effects due to on orbit attitude control maneuvers. Such maneuvers are expected to advance the sail to a position off-normal to the sun by as much as 35 degrees; a solar sail initially deformed by typical pre-tension and solar pressure loads may suffer significant thermally induced strains due to the non-uniform heating caused by these maneuvers. This on-orbit scenario was investigated through development of an automated analytical shape model that iterates many times between sail shape and sail temperature distribution before converging on a final coupled thermal structural affected sail topology. This model utilizes a validated geometrically non-linear finite element model and a thermal radiation subroutine. It was discovered that temperature gradients were deterministic for the off-normal solar angle cases as were thermally induced strains. Performance effects were found to be moderately significant but not as large as initially suspected. A roll torque was detected, and the sail center of pressure shifted by a distance that may influence on-orbit sail control stability.

  6. Variation of surface ozone in Campo Grande, Brazil: meteorological effect analysis and prediction.

    PubMed

    Pires, J C M; Souza, A; Pavão, H G; Martins, F G

    2014-09-01

    The effect of meteorological variables on surface ozone (O3) concentrations was analysed based on temporal variation of linear correlation and artificial neural network (ANN) models defined by genetic algorithms (GAs). ANN models were also used to predict the daily average concentration of this air pollutant in Campo Grande, Brazil. Three methodologies were applied using GAs, two of them considering threshold models. In these models, the variables selected to define different regimes were daily average O3 concentration, relative humidity and solar radiation. The threshold model that considers two O3 regimes was the one that correctly describes the effect of important meteorological variables in O3 behaviour, presenting also a good predictive performance. Solar radiation, relative humidity and rainfall were considered significant for both O3 regimes; however, wind speed (dispersion effect) was only significant for high concentrations. According to this model, high O3 concentrations corresponded to high solar radiation, low relative humidity and wind speed. This model showed to be a powerful tool to interpret the O3 behaviour, being useful to define policy strategies for human health protection regarding air pollution. PMID:24854500

  7. Nationwide variation in the effects of temperature on infectious gastroenteritis incidence in Japan

    PubMed Central

    Onozuka, Daisuke; Hagihara, Akihito

    2015-01-01

    Although several studies have investigated the effects of temperature on the incidence of infectious gastrointestinal disease in a single city or region, few have investigated variations in this association using nationwide data. We obtained weekly data, gathered between 2000 and 2012, pertaining to infectious gastroenteritis cases and weather variability in all 47 Japanese prefectures. A two-stage analysis was used to assess the nonlinear and delayed relationship between temperature and morbidity. In the first stage, a Poisson regression allowing for overdispersion in a distributed lag nonlinear model was used to estimate the prefecture-specific effects of temperature on morbidity. In the second stage, a multivariate meta-analysis was applied to pool estimates at the national level. The pooled overall relative risk (RR) was highest in the 59.9th percentile of temperature (RR, 1.08; 95% CI: 1.01, 1.15). Meta-analysis results also indicated that the estimated pooled RR at lower temperatures (25th percentile) began immediately but did not persist, whereas an identical estimate at a higher temperature (75th percentile) was delayed but persisted for several weeks. Our results suggest that public health strategies aimed at controlling temperature-related infectious gastroenteritis may be more effective when tailored according to region-specific weather conditions. PMID:26255569

  8. Secular orbit variation due to solar radiation effects: a detailed model for BYORP

    NASA Astrophysics Data System (ADS)

    McMahon, Jay; Scheeres, Daniel

    2010-03-01

    A detailed derivation of the effect of solar radiation pressure on the orbit of a body about a primary orbiting the Sun is given. The result is a set of secular equations that can be used for long-term predictions of changes in the orbit. Solar radiation pressure is modeled as a Fourier series in the body’s rotation state, where the coefficients are based on the shape and radiation properties of the body as parameters. In this work, the assumption is made that the body is in a synchronous orbit about the primary and rotates at a constant rate. This model is used to write explicit variational equations of the energy, eccentricity vector, and angular momentum vector for an orbiting body. Given that the effect of the solar radiation pressure and the orbit are periodic functions, they are readily averaged over an orbit. Furthermore, the equations can be averaged again over the orbit of the primary about the Sun to give secular equations for long-term prediction. This methodology is applied to both circular and elliptical orbits, and the full equations for secular changes to the orbit in both cases are presented. These results can be applied to natural systems, such as the binary asteroid system 1999 KW4, to predict their evolution due to the Binary YORP effect, or to artificial Earth orbiting, nadir-pointing satellites to enable more precise models for their orbital evolution.

  9. Prey state shapes the effects of temporal variation in predation risk.

    PubMed

    Matassa, Catherine M; Trussell, Geoffrey C

    2014-12-01

    The ecological impacts of predation risk are influenced by how prey allocate foraging effort across periods of safety and danger. Foraging decisions depend on current danger, but also on the larger temporal, spatial or energetic context in which prey manage their risks of predation and starvation. Using a rocky intertidal food chain, we examined the responses of starved and fed prey (Nucella lapillus dogwhelks) to different temporal patterns of risk from predatory crabs (Carcinus maenas). Prey foraging activity declined during periods of danger, but as dangerous periods became longer, prey state altered the magnitude of risk effects on prey foraging and growth, with likely consequences for community structure (trait-mediated indirect effects on basal resources, Mytilus edulis mussels), prey fitness and trophic energy transfer. Because risk is inherently variable over time and space, our results suggest that non-consumptive predator effects may be most pronounced in productive systems where prey can build energy reserves during periods of safety and then burn these reserves as 'trophic heat' during extended periods of danger. Understanding the interaction between behavioural (energy gain) and physiological (energy use) responses to risk may illuminate the context dependency of trait-mediated trophic cascades and help explain variation in food chain length. PMID:25339716

  10. Prey state shapes the effects of temporal variation in predation risk

    PubMed Central

    Matassa, Catherine M.; Trussell, Geoffrey C.

    2014-01-01

    The ecological impacts of predation risk are influenced by how prey allocate foraging effort across periods of safety and danger. Foraging decisions depend on current danger, but also on the larger temporal, spatial or energetic context in which prey manage their risks of predation and starvation. Using a rocky intertidal food chain, we examined the responses of starved and fed prey (Nucella lapillus dogwhelks) to different temporal patterns of risk from predatory crabs (Carcinus maenas). Prey foraging activity declined during periods of danger, but as dangerous periods became longer, prey state altered the magnitude of risk effects on prey foraging and growth, with likely consequences for community structure (trait-mediated indirect effects on basal resources, Mytilus edulis mussels), prey fitness and trophic energy transfer. Because risk is inherently variable over time and space, our results suggest that non-consumptive predator effects may be most pronounced in productive systems where prey can build energy reserves during periods of safety and then burn these reserves as ‘trophic heat’ during extended periods of danger. Understanding the interaction between behavioural (energy gain) and physiological (energy use) responses to risk may illuminate the context dependency of trait-mediated trophic cascades and help explain variation in food chain length. PMID:25339716

  11. Effect of variations in globulin concentrations on serum radioimmunoassay results, as exemplified by choriogonadotropin

    SciTech Connect

    Jawad, M.J.; Wilson, E.A.

    1981-12-01

    Variations in serum protein concentrations can affect results of radioimmunoassay of human choriogonadotropin involving either polyethylene glycol or double-antibody methods of separation. Relative to the maximal binding of choriogonadotropin in the presence of normal (30 g/L) globulin concentrations, globulin concentrations of 10 to 60 g/L were associated with maximal binding ranging from 84.9 to 115.6% in the polyethylene glycol system, and from 109.9 to 92.5% in the double-antibody system. This effect was quantitatively much the same throughout the standard curve in the polyethylene glycol system, but diminished with the higher standard concentrations in the double-antibody system. In assays involving polyethylene glycol separation, an increase in globulin was associated with a linear increase in nonspecific binding, but no detectable effect of globulin on nonspecific binding was observed in the double-antibody system. Determination and compensation for nonspecific binding of individual samples (rather than for mean assay nonspecific binding) eliminated the globulin effect in the polyethylene glycol system but not in the double-antibody system.

  12. Effect of C/N shock variation on the performances of a moving bed membrane bioreactor.

    PubMed

    Di Trapani, Daniele; Di Bella, Gaetano; Mannina, Giorgio; Torregrossa, Michele; Viviani, Gaspare

    2015-08-01

    The effect of a sharp variation of C/N ratio in a moving bed membrane bioreactor (MB-MBR) pilot plant treating high strength wastewater has been investigated. The experimental campaign was divided into two periods, each characterized by a different C/N ratio (namely, 2.5 and 15, Period 1 and Period 2, respectively). The MB-MBR system was analyzed in terms of organic carbon removal, nitrification efficiency, biokinetic activity and fouling behavior. The results showed that the nitrification process was severely affected by lower C/N value and by high concentration of ammonia. It was noticed an extensive stress effect on the autotrophic bacteria. Furthermore, it was observed an increase of the resistance related to particle deposition into membrane pores, likely due to a worsening of the cake layer features, with a reduction of the "pre-filter" effect, also related to the increase of the total Extracellular Polymeric Substances production with the C/N ratio. PMID:25898086

  13. Nationwide variation in the effects of temperature on infectious gastroenteritis incidence in Japan

    NASA Astrophysics Data System (ADS)

    Onozuka, Daisuke; Hagihara, Akihito

    2015-08-01

    Although several studies have investigated the effects of temperature on the incidence of infectious gastrointestinal disease in a single city or region, few have investigated variations in this association using nationwide data. We obtained weekly data, gathered between 2000 and 2012, pertaining to infectious gastroenteritis cases and weather variability in all 47 Japanese prefectures. A two-stage analysis was used to assess the nonlinear and delayed relationship between temperature and morbidity. In the first stage, a Poisson regression allowing for overdispersion in a distributed lag nonlinear model was used to estimate the prefecture-specific effects of temperature on morbidity. In the second stage, a multivariate meta-analysis was applied to pool estimates at the national level. The pooled overall relative risk (RR) was highest in the 59.9th percentile of temperature (RR, 1.08; 95% CI: 1.01, 1.15). Meta-analysis results also indicated that the estimated pooled RR at lower temperatures (25th percentile) began immediately but did not persist, whereas an identical estimate at a higher temperature (75th percentile) was delayed but persisted for several weeks. Our results suggest that public health strategies aimed at controlling temperature-related infectious gastroenteritis may be more effective when tailored according to region-specific weather conditions.

  14. Assessing the Effect of a Contouring Protocol on Postprostatectomy Radiotherapy Clinical Target Volumes and Interphysician Variation

    SciTech Connect

    Mitchell, Darren M.; Perry, Lesley; Smith, Steve; Elliott, Tony; Wylie, James P.; Cowan, Richard A.; Livsey, Jacqueline E.; Logue, John P.

    2009-11-15

    Purpose: To compare postprostatectomy clinical target volume (CTV) delineation before and after the introduction of a contouring protocol and to investigate its effect on interphysician variability Methods and Materials: Six site-specialized radiation oncologists independently delineated a CTV on the computed tomography (CT) scans of 3 patients who had received postprostatectomy radiotherapy. At least 3 weeks later this was repeated, but with the physicians adhering to the contouring protocol from the Medical Research Council's Radiotherapy and Androgen Deprivation In Combination After Local Surgery (RADICALS) trial. The volumes obtained before and after the protocol were compared and the effect of the protocol on interphysician variability assessed. Results: An increase in mean CTV for all patients of 40.7 to 53.9cm{sup 3} was noted as a result of observing the protocol, with individual increases in the mean CTV of 65%, 15%, and 24% for Patients 1, 2, and 3 respectively. A reduction in interphysician variability was noted when the protocol was used. Conclusions: Substantial interphysician variation in target volume delineation for postprostatectomy radiotherapy exists, which can be reduced by the use of a contouring protocol. The RADICALS contouring protocol increases the target volumes when compared with those volumes typically applied at our center. The effect of treating larger volumes on the therapeutic ratio and resultant toxicity should be carefully monitored, particularly if the same dose-response as documented in radical prostate radiotherapy applies to the adjuvant and salvage setting. Prostate cancer, Postprostatectomy, Radiotherapy, Target volume.

  15. A model for the temperature and composition effects in the semiannual variations of the thermospheric density

    NASA Technical Reports Server (NTRS)

    Mayr, H. G.; Volland, H.

    1971-01-01

    A model is proposed in which latitudinal variations in composition and temperature are used to interpret the semiannual effect in the thermospheric density. Two heat sources are postulated for the semiannual circulation: one at high latitudes associated with the semiannual component in the occurance of magnetic storms and a second weaker one that peaks at the equator associated with the semiannual migration between both hemispheres. Depending on the relative magnitude of these sources, the latitude regions in which composition and temperature effects dominate vary. The temperature effects however should be expected weakest at low to mid latitudes where the relative concentration of atomic oxygen is enriched during equinox. At high latitudes the semiannual temperature component would peak, associated with an oxygen depletion in the lower thermosphere during equinox. In combining these features it is shown that the total atmospheric density could still exhibit a relatively small latitude dependence in the semiannual component with the tendency to decrease at high latitudes, in agreement with observations.

  16. Effect of normal load variation on the frictional behavior of a simple Coulomb frictional oscillator

    NASA Astrophysics Data System (ADS)

    Papangelo, A.; Ciavarella, M.

    2015-07-01

    Various authors have studied the frictional contact problem for a simple concentrated mass under periodic forcing terms. In this paper, we give some additional closed form results for this problem for both the quasi-static limit and the full dynamic regime. We find in particular the regime where normal load is high enough to obtain a bounded displacement at all frequencies, which is of particular interest for "optimal" damping: in this case, the dynamic solution involves 2 stops of finite time. Contrary to the quasi-static prediction, the effect of normal load variation can decrease the peak displacement amplitude for in-phase loading up to the 80 percent. Moreover, similar to the quasi-static prediction, it can lead to a very large increase (up to more than 200 percent) for quadrature loading. Similar pattern is found for the frictional dissipation per cycle. For in-phase loading, therefore, the vibratory motion is damped more effectively, with additional beneficial effects on joint lifetime.

  17. A technical perspective in modern tree-ring research--how to overcome dendroecological and wood anatomical challenges.

    PubMed

    Gärtner, Holger; Cherubini, Paolo; Fonti, Patrick; von Arx, Georg; Schneider, Loïc; Nievergelt, Daniel; Verstege, Anne; Bast, Alexander; Schweingruber, Fritz H; Büntgen, Ulf

    2015-01-01

    Dendroecological research uses information stored in tree rings to understand how single trees and even entire forest ecosystems responded to environmental changes and to finally reconstruct such changes. This is done by analyzing growth variations back in time and correlating various plant-specific parameters to (for example) temperature records. Integrating wood anatomical parameters in these analyses would strengthen reconstructions, even down to intra-annual resolution. We therefore present a protocol on how to sample, prepare, and analyze wooden specimen for common macroscopic analyses, but also for subsequent microscopic analyses. Furthermore we introduce a potential solution for analyzing digital images generated from common small and large specimens to support time-series analyses. The protocol presents the basic steps as they currently can be used. Beyond this, there is an ongoing need for the improvement of existing techniques, and development of new techniques, to record and quantify past and ongoing environmental processes. Traditional wood anatomical research needs to be expanded to include ecological information to this field of research. This would support dendro-scientists who intend to analyze new parameters and develop new methodologies to understand the short and long term effects of specific environmental factors on the anatomy of woody plants. PMID:25866965

  18. A Technical Perspective in Modern Tree-ring Research - How to Overcome Dendroecological and Wood Anatomical Challenges

    PubMed Central

    Gärtner, Holger; Cherubini, Paolo; Fonti, Patrick; von Arx, Georg; Schneider, Loïc; Nievergelt, Daniel; Verstege, Anne; Bast, Alexander; Schweingruber, Fritz H.; Büntgen, Ulf

    2015-01-01

    Dendroecological research uses information stored in tree rings to understand how single trees and even entire forest ecosystems responded to environmental changes and to finally reconstruct such changes. This is done by analyzing growth variations back in time and correlating various plant-specific parameters to (for example) temperature records. Integrating wood anatomical parameters in these analyses would strengthen reconstructions, even down to intra-annual resolution. We therefore present a protocol on how to sample, prepare, and analyze wooden specimen for common macroscopic analyses, but also for subsequent microscopic analyses. Furthermore we introduce a potential solution for analyzing digital images generated from common small and large specimens to support time-series analyses. The protocol presents the basic steps as they currently can be used. Beyond this, there is an ongoing need for the improvement of existing techniques, and development of new techniques, to record and quantify past and ongoing environmental processes. Traditional wood anatomical research needs to be expanded to include ecological information to this field of research. This would support dendro-scientists who intend to analyze new parameters and develop new methodologies to understand the short and long term effects of specific environmental factors on the anatomy of woody plants. PMID:25866965

  19. Assemblage organization in stream fishes: effects of environmental variation and interspecific interactions

    USGS Publications Warehouse

    Grossman, G.D.; Ratajczak, R.E., Jr.; Crawford, M. M.; Freeman, Mary C.

    1998-01-01

    We assessed the relative importance of environmental variation, interspecific competition for space, and predator abundance on assemblage structure and microhabitat use in a stream fish assemblage inhabiting Coweeta Creek, North Carolina, USA. Our study encompassed a ten year time span (1983-1992) and included some of the highest and lowest flows in the last 58 years. We collected 16 seasonal samples which included data on: 1) habitat availability (total and microhabitat) and microhabitat diversity, 2) assemblage structure (i.e., the number and abundances of species comprising a subset of the community), and 3) microhabitat use and overlap. We classified habitat availability data on the basis of year, season, and hydrologic period. Hydrologic period (i.e., pre-drought [PR], drought [D], and post-drought [PO]) represented the temporal location of a sample with respect to a four-year drought that occurred during the study. Hydrologic period explained a greater amount of variance in habitat availability data than either season or year. Total habitat availability was significantly greater during PO than in PR or D, although microhabitat diversity did not differ among either seasons or hydrologic periods. There were significantly fewer high-flow events (i.e., > 2.1 m3/s) during D than in either PR or PO periods. We observed a total of 16 species during our investigation, and the total number of species was significantly higher in D than in PR samples. Correlation analyses between the number of species present (total and abundant species) and environmental data yielded limited results, although the total number of species was inversely correlated with total habitat availability. A cluster analysis grouped assemblage structure samples by hydrologic period rather than season or year, supporting the contention that variation in annual flow had a strong impact on this assemblage. The drought had little effect on the numerical abundance of benthic species in this assemblage

  20. Untangling Natural Seascape Variation from Marine Reserve Effects Using a Landscape Approach

    PubMed Central

    Huntington, Brittany E.; Karnauskas, Mandy; Babcock, Elizabeth A.; Lirman, Diego

    2010-01-01

    Distinguishing management effects from the inherent variability in a system is a key consideration in assessing reserve efficacy. Here, we demonstrate how seascape heterogeneity, defined as the spatial configuration and composition of coral reef habitats, can mask our ability to discern reserve effects. We then test the application of a landscape approach, utilizing advances in benthic habitat mapping and GIS techniques, to quantify this heterogeneity and alleviate the confounding influence during reserve assessment. Seascape metrics were quantified at multiple spatial scales using a combination of spatial image analysis and in situ surveys at 87 patch reef sites in Glover's Reef Lagoon, Belize, within and outside a marine reserve enforced since 1998. Patch reef sites were then clustered into classes sharing similar seascape attributes using metrics that correlated significantly to observed variations in both fish and coral communities. When the efficacy of the marine reserve was assessed without including landscape attributes, no reserve effects were detected in the diversity and abundance of fish and coral communities, despite 10 years of management protection. However, grouping sites based on landscape attributes revealed significant reserve effects between site classes. Fish had higher total biomass (1.5×) and commercially important biomass (1.75×) inside the reserve and coral cover was 1.8 times greater inside the reserve, though direction and degree of response varied by seascape class. Our findings show that the application of a landscape classification approach vastly improves our ability to evaluate the efficacy of marine reserves by controlling for confounding effects of seascape heterogeneity and suggests that landscape heterogeneity should be considered in future reserve design. PMID:20808833

  1. Understanding Long-Term Variations in an Elephant Piosphere Effect to Manage Impacts

    PubMed Central

    Landman, Marietjie; Schoeman, David S.; Hall-Martin, Anthony J.; Kerley, Graham I. H.

    2012-01-01

    Surface water availability is a key driver of elephant impacts on biological diversity. Thus, understanding the spatio-temporal variations of these impacts in relation to water is critical to their management. However, elephant piosphere effects (i.e. the radial pattern of attenuating impact) are poorly described, with few long-term quantitative studies. Our understanding is further confounded by the complexity of systems with elephant (i.e. fenced, multiple water points, seasonal water availability, varying population densities) that likely limit the use of conceptual models to predict these impacts. Using 31 years of data on shrub structure in the succulent thickets of the Addo Elephant National Park, South Africa, we tested elephant effects at a single water point. Shrub structure showed a clear sigmoid response with distance from water, declining at both the upper and lower limits of sampling. Adjacent to water, this decline caused a roughly 300-m radial expansion of the grass-dominated habitats that replace shrub communities. Despite the clear relationship between shrub structure and ecological functioning in thicket, the extent of elephant effects varied between these features with distance from water. Moreover, these patterns co-varied with other confounding variables (e.g. the location of neighboring water points), which limits our ability to predict such effects in the absence of long-term data. We predict that elephant have the ability to cause severe transformation in succulent thicket habitats with abundant water supply and elevated elephant numbers. However, these piosphere effects are complex, suggesting that a more integrated understanding of elephant impacts on ecological heterogeneity may be required before water availability is used as a tool to manage impacts. We caution against the establishment of water points in novel succulent thicket habitats, and advocate a significant reduction in water provisioning at our study site, albeit with greater

  2. Understanding long-term variations in an elephant piosphere effect to manage impacts.

    PubMed

    Landman, Marietjie; Schoeman, David S; Hall-Martin, Anthony J; Kerley, Graham I H

    2012-01-01

    Surface water availability is a key driver of elephant impacts on biological diversity. Thus, understanding the spatio-temporal variations of these impacts in relation to water is critical to their management. However, elephant piosphere effects (i.e. the radial pattern of attenuating impact) are poorly described, with few long-term quantitative studies. Our understanding is further confounded by the complexity of systems with elephant (i.e. fenced, multiple water points, seasonal water availability, varying population densities) that likely limit the use of conceptual models to predict these impacts. Using 31 years of data on shrub structure in the succulent thickets of the Addo Elephant National Park, South Africa, we tested elephant effects at a single water point. Shrub structure showed a clear sigmoid response with distance from water, declining at both the upper and lower limits of sampling. Adjacent to water, this decline caused a roughly 300-m radial expansion of the grass-dominated habitats that replace shrub communities. Despite the clear relationship between shrub structure and ecological functioning in thicket, the extent of elephant effects varied between these features with distance from water. Moreover, these patterns co-varied with other confounding variables (e.g. the location of neighboring water points), which limits our ability to predict such effects in the absence of long-term data. We predict that elephant have the ability to cause severe transformation in succulent thicket habitats with abundant water supply and elevated elephant numbers. However, these piosphere effects are complex, suggesting that a more integrated understanding of elephant impacts on ecological heterogeneity may be required before water availability is used as a tool to manage impacts. We caution against the establishment of water points in novel succulent thicket habitats, and advocate a significant reduction in water provisioning at our study site, albeit with greater

  3. Global variation in the effects of ambient temperature on mortality: a systematic evaluation

    PubMed Central

    Guo, Yuming; Gasparrini, Antonio; Armstrong, Ben; Li, Shanshan; Tawatsupa, Benjawan; Tobias, Aurelio; Lavigne, Eric; de Sousa Zanotti Stagliorio Coelho, Micheline; Leone, Michela; Pan, Xiaochuan; Tong, Shilu; Tian, Linwei; Kim, Ho; Hashizume, Masahiro; Honda, Yasushi; Guo, Yue-Liang Leon; Wu, Chang-Fu; Punnasiri, Kornwipa; Yi, Seung-Muk; Michelozzi, Paola; Saldiva, Paulo Hilario Nascimento; Williams, Gail

    2014-01-01

    Background Studies have examined the effects of temperature on mortality in a single city, country or region. However, less evidence is available on the variation in the associations between temperature and mortality in multiple countries, analyzed simultaneously. Methods We obtained daily data on temperature and mortality in 306 communities from 12 countries/regions (Australia, Brazil, Thailand, China, Taiwan, Korea, Japan, Italy, Spain, United Kingdom, United States and Canada). Two-stage analyses were used to assess the non-linear and delayed relationship between temperature and mortality. In the first stage, a Poisson regression allowing over-dispersion with distributed lag non-linear model was used to estimate the community-specific temperature-mortality relationship. In the second stage, a multivariate meta-analysis was used to pool the non-linear and delayed effects of ambient temperature at the national level, in each country. Results The temperatures associated with the lowest mortality were around the 75th percentile of temperature in all the countries/regions, ranging from 66th (Taiwan) to 80th (UK) percentiles. The estimated effects of cold and hot temperatures on mortality varied by community and country. Meta-analysis results show that both cold and hot temperatures increased the risk of mortality in all the countries/regions. Cold effects were delayed and lasted for many days, while hot effects appeared quickly and did not last long. Conclusions People have some ability to adapt to their local climate type, but both cold and hot temperatures are still associated with the risk of mortality. Public health strategies to alleviate the impact of ambient temperatures are important, in particular in the context of climate change. PMID:25166878

  4. Untangling natural seascape variation from marine reserve effects using a landscape approach.

    PubMed

    Huntington, Brittany E; Karnauskas, Mandy; Babcock, Elizabeth A; Lirman, Diego

    2010-01-01

    Distinguishing management effects from the inherent variability in a system is a key consideration in assessing reserve efficacy. Here, we demonstrate how seascape heterogeneity, defined as the spatial configuration and composition of coral reef habitats, can mask our ability to discern reserve effects. We then test the application of a landscape approach, utilizing advances in benthic habitat mapping and GIS techniques, to quantify this heterogeneity and alleviate the confounding influence during reserve assessment. Seascape metrics were quantified at multiple spatial scales using a combination of spatial image analysis and in situ surveys at 87 patch reef sites in Glover's Reef Lagoon, Belize, within and outside a marine reserve enforced since 1998. Patch reef sites were then clustered into classes sharing similar seascape attributes using metrics that correlated significantly to observed variations in both fish and coral communities. When the efficacy of the marine reserve was assessed without including landscape attributes, no reserve effects were detected in the diversity and abundance of fish and coral communities, despite 10 years of management protection. However, grouping sites based on landscape attributes revealed significant reserve effects between site classes. Fish had higher total biomass (1.5x) and commercially important biomass (1.75x) inside the reserve and coral cover was 1.8 times greater inside the reserve, though direction and degree of response varied by seascape class. Our findings show that the application of a landscape classification approach vastly improves our ability to evaluate the efficacy of marine reserves by controlling for confounding effects of seascape heterogeneity and suggests that landscape heterogeneity should be considered in future reserve design. PMID:20808833

  5. Effects of disfluencies, predictability, and utterance position on word form variation in English conversation

    NASA Astrophysics Data System (ADS)

    Bell, Alan; Jurafsky, Daniel; Fosler-Lussier, Eric; Girand, Cynthia; Gregory, Michelle; Gildea, Daniel

    2003-02-01

    Function words, especially frequently occurring ones such as (the, that, and, and of ), vary widely in pronunciation. Understanding this variation is essential both for cognitive modeling of lexical production and for computer speech recognition and synthesis. This study investigates which factors affect the forms of function words, especially whether they have a fuller pronunciation (e.g., edh,eye, edh,æ,tee, æ,en,&dee, vee) or a more reduced or lenited pronunciation (e.g., edh,schwa, edh,bari;t, n, schwa). It is based on over 8000 occurrences of the ten most frequent English function words in a 4-h sample from conversations from the Switchboard corpus. Ordinary linear and logistic regression models were used to examine variation in the length of the words, in the form of their vowel (basic, full, or reduced), and whether final obstruents were present or not. For all these measures, after controlling for segmental context, rate of speech, and other important factors, there are strong independent effects that made high-frequency monosyllabic function words more likely to be longer or have a fuller form (1) when neighboring disfluencies (such as filled pauses uh and um) indicate that the speaker was encountering problems in planning the utterance; (2) when the word is unexpected, i.e., less predictable in context; (3) when the word is either utterance initial or utterance final. Looking at the phenomenon in a different way, frequent function words are more likely to be shorter and to have less-full forms in fluent speech, in predictable positions or multiword collocations, and utterance internally. Also considered are other factors such as sex (women are more likely to use fuller forms, even after controlling for rate of speech, for example), and some of the differences among the ten function words in their response to the factors.

  6. Effects of the Observed Meridional Flow Variations since 1996 on the Sun's Polar Fields