Browsing by Subject "Dogs"

Now showing 1 - 7 of 7

Open Access
Çok kollu haydutlar ile dinamik ambulans konumlandırma
(IEEE, 2019-04) Şahin, Ümitcan; Yücesoy, V.
Bir ülkenin acil yardım sistemlerinin iyileştirilmesi, daha çok acil vakaya zamanında müdahale edilmesi ve daha çok hayatın kurtarılmasını sağlar. 112 Acil Yardım sisteminin bir parçası olan ambulans konumlandırma problemi, ambulansların vakalara mümkün olan en kısa sürede ulaşmasını sağlayacak şekilde konumlandırılmasını sağlayan birçok yöntemden oluşur. Bu çalışmada ambulanslar, literatürdeki yöntemlerin aksine, bir çok kollu haydut (ÇKH) algoritması kullanılarak konumlandırılmaktadır. OpenStreetMap (OSM) harita uygulaması kullanılarak oluşturulmuş iki yönlü kenarlardan ve toplam 2400 düğümden oluşan bir Ankara şehri haritası üzerinde konumlandırma işlemi yapılmaktadır. Düğümler üzerindeki vaka dağılımları ve aralarındaki seyahat süreleri ÇKH algoritması tarafından bilinmemektedir ve zamanla öğrenilmektedir. Bu öğrenim keşif ve istifade arasındaki ödünleşim sistemi ile sağlanmaktadır. Algoritma karşılaştırmaları için literatürde sıkça kullanılan ve dinamik bir konumlandırma yöntemi olan DMEXCLP modeli kullanılmıştır. Simülasyonlarda algoritma karşılaştırmaları için iki ölçüt değerlendirilmiştir: 1) vakalara ortalama müdahale süresi ve 2) 15 dakika altında varılan vaka yüzdesi. Sonuç olarak aynı şartlar altında önerilen ÇKH algoritmasının DMEXCLP modeline göre bu iki ölçüt açısından daha iyi performans verdiği gösterilmiştir.
Open Access
Demographically-based evaluation of genomic regions under selection in domestic dogs
(Public Library of Science, 2016) Freedman, A. H.; Schweizer, R. M.; Vecchyo, D. Ortega-Del; Han, E.; Davis, B. W.; Gronau, I.; Silva, P. M.; Galaverni, M.; Fan, Z.; Marx, P.; Lorente-Galdos, B.; Ramirez, O.; Hormozdiari, F.; Alkan C.; Vilà, C.; Squire K.; Geffen, E.; Kusak, J.; Boyko, A. R.; Parker, H. G.; Lee C.; Tadigotla, V.; Siepel, A.; Bustamante, C. D.; Harkins, T. T.; Nelson, S. F.; Marques Bonet, T.; Ostrander, E. A.; Wayne, R. K.; Novembre, J.
Controlling for background demographic effects is important for accurately identifying loci that have recently undergone positive selection. To date, the effects of demography have not yet been explicitly considered when identifying loci under selection during dog domestication. To investigate positive selection on the dog lineage early in the domestication, we examined patterns of polymorphism in six canid genomes that were previously used to infer a demographic model of dog domestication. Using an inferred demographic model, we computed false discovery rates (FDR) and identified 349 outlier regions consistent with positive selection at a low FDR. The signals in the top 100 regions were frequently centered on candidate genes related to brain function and behavior, including LHFPL3, CADM2, GRIK3, SH3GL2, MBP, PDE7B, NTAN1, and GLRA1. These regions contained significant enrichments in behavioral ontology categories. The 3rdtop hit, CCRN4L, plays a major role in lipid metabolism, that is supported by additional metabolism related candidates revealed in our scan, including SCP2D1 and PDXC1. Comparing our method to an empirical outlier approach that does not directly account for demography, we found only modest overlaps between the two methods, with 60% of empirical outliers having no overlap with our demography-based outlier detection approach. Demography-aware approaches have lower-rates of false discovery. Our top candidates for selection, in addition to expanding the set of neurobehavioral candidate genes, include genes related to lipid metabolism, suggesting a dietary target of selection that was important during the period when proto-dogs hunted and fed alongside hunter-gatherers. © 2016, Public Library of Science. All Rights Reserved.
Open Access
Design of a novel MRI compatible manipulator for image guided prostate interventions
(IEEE, 2005-02) Krieger, A.; Susil, R. C.; Ménard, C.; Coleman, J. A.; Fichtinger, G.; Atalar, Ergin; Whitcomb, L. L.
This paper reports a novel remotely actuated manipulator for access to prostate tissue under magnetic resonance imaging guidance (APT-MRI) device, designed for use in a standard high-field MRI scanner. The device provides three-dimensional MRI guided needle placement with millimeter accuracy under physician control. Procedures enabled by this device include MRI guided needle biopsy, fiducial marker placements, and therapy delivery. Its compact size allows for use in both standard cylindrical and open configuration MRI scanners. Preliminary in vivo canine experiments and first clinical trials are reported.
Open Access
Genome sequencing highlights the dynamic early history of dogs
(Public Library of Science, 2014) Freedman, A. H.; Gronau I.; Schweizer, R. M.; Ortega-Del Vecchyo, D.; Han, E.; Silva, P. M.; Galaverni, M.; Fan, Z.; Marx P.; Lorente-Galdos, B.; Beale, H.; Ramirez, O.; Hormozdiari, F.; Alkan C.; Vilà, C.; Squire K.; Geffen, E.; Kusak, J.; Boyko, A. R.; Parker, H. G.; Lee C.; Tadigotla, V.; Siepel, A.; Bustamante, C. D.; Harkins, T. T.; Nelson, S. F.; Ostrander, E. A.; Marques Bonet, T.; Wayne, R. K.; Novembre, J.
To identify genetic changes underlying dog domestication and reconstruct their early evolutionary history, we generated high-quality genome sequences from three gray wolves, one from each of the three putative centers of dog domestication, two basal dog lineages (Basenji and Dingo) and a golden jackal as an outgroup. Analysis of these sequences supports a demographic model in which dogs and wolves diverged through a dynamic process involving population bottlenecks in both lineages and post-divergence gene flow. In dogs, the domestication bottleneck involved at least a 16-fold reduction in population size, a much more severe bottleneck than estimated previously. A sharp bottleneck in wolves occurred soon after their divergence from dogs, implying that the pool of diversity from which dogs arose was substantially larger than represented by modern wolf populations. We narrow the plausible range for the date of initial dog domestication to an interval spanning 11-16 thousand years ago, predating the rise of agriculture. In light of this finding, we expand upon previous work regarding the increase in copy number of the amylase gene (AMY2B) in dogs, which is believed to have aided digestion of starch in agricultural refuse. We find standing variation for amylase copy number variation in wolves and little or no copy number increase in the Dingo and Husky lineages. In conjunction with the estimated timing of dog origins, these results provide additional support to archaeological finds, suggesting the earliest dogs arose alongside hunter-gathers rather than agriculturists. Regarding the geographic origin of dogs, we find that, surprisingly, none of the extant wolf lineages from putative domestication centers is more closely related to dogs, and, instead, the sampled wolves form a sister monophyletic clade. This result, in combination with dog-wolf admixture during the process of domestication, suggests that a re-evaluation of past hypotheses regarding dog origins is necessary. © 2014.
Open Access
Intravascular extended sensitivity (IVES) MRI antennas
(John Wiley & Sons, Inc, 2003) Susil, R. C.; Yeung, C. J.; Atalar, Ergin
The design and application of an intravascular extended sensitivity (IVES) MRI antenna is described. The device is a loopless antenna design that incorporates both an insulating, dielectric coating and a winding of the antenna whip into a helical shape. Because this antenna produces a broad region of high SNR and also allows for imaging near the tip of the device, it is useful for imaging long, luminal structures. To elucidate the design and function of this device, the effects of both insulation and antenna winding were characterized by theoretical and experimental studies. Insulation broadens the longitudinal region over which images can be collected (i.e., along the lumen of a vessel) by increasing the resonant pole length. Antenna winding, conversely, allows for imaging closer to the tip of the antenna by decreasing the resonant pole length. Over a longitudinal region of 20 cm, the IVES imaging antenna described here produces a system SNR of approximately 40,000/r (mL-1Hz1/2), where r is the radial distance from the antenna axis in centimeters. As opposed to microcoil antenna designs, these antennas do not require exact positioning and allow for imaging over broad tissue regions. While focusing on the design of the IVES antenna, this work also serves to enhance our overall understanding of the properties and behavior of the loopless antenna design. © 2003 Wiley-Liss, Inc.
Open Access
Phased-array MRI of canine prostate using endorectal and endourethral coils
(John Wiley & Sons, Inc., 2003) Yung, A. C.; Oner, A. Y.; Serfaty, J-M.; Feneley, M.; Yang, X.; Atalar, Ergin
A four-channel phased array consisting of one surface coil, two endorectal coils, and one flexible endourethral loop coil was designed for MRI of the canine prostate. The endorectal coils provide high signal in the posterior region of the prostate, while the endourethral and surface coils are sensitive to the central and anterior regions of the prostate. Gel phantom experiments indicate that the proposed phased-array configuration generates 15 times more signal-to-noise ratio (SNR) than a combination of two surface coils and one endorectal coil within the posterior region of the prostate; the performance of the two configurations is comparable near the anterior prostate surface. Ultimate intrinsic SNR (UISNR) analysis was used to compare the proposed phased array's performance to the best possible SNR for external coils. This analysis showed that the proposed phased array outperforms the best-case external coil within the posterior and central regions of the prostate by up to 20 times. In canine experiments in vivo, high-resolution fast spin-echo (FSE) images of the prostate were obtained with a pixel size of 230 μm obtained in 3 min 12 s. The proposed phased-array design potentially can be used to increase the accuracy of prostate cancer staging and the feasibility of MR-guided prostate interventions. © 2003 Wiley-Liss, Inc.
Open Access
System for MR image-guided prostate interventions: Canine study
(Radiological Society of North America, Inc., 2003) Susil, R. C.; Krieger, A.; Derbyshire, J. A.; Tanacs, A.; Whitcomb, L. L.; Fichtinger, G.; Atalar, Ergin
The purpose of this study was to demonstrate the use of a transrectal system that enables precise magnetic resonance (MR) image guidance and monitoring of prostate interventions. The system used a closed-bore 1.5-T MR imaging unit and enables one to take advantage of the higher signal-to-noise ratio achieved with traditional magnet designs, which is crucial for accurate targeting and monitoring of prostate interventions. In the first of the four canine studies, reliable needle placement, with all needles placed within 2 mm of the desired target site, was achieved. In two other studies, MR imaging was used to monitor distribution of injected contrast agent solution (gadopentetate dimeglumine mixed with trypan blue dye) in and around the prostate, thereby confirming that solution had been delivered to the desired tissue and also detecting faulty injections. In the final study, accurate placement and MR imaging of brachytherapy seeds in the prostate were demonstrated. The described system provides a flexible platform for a variety of minimally invasive MR image-guided therapeutic and diagnostic prostate interventions. © RSNA, 2003.