Optimization of 3D texture analysis of MR cartilage images for prediction of knee osteoarthritis

Abstract. This thesis attempted to optimize a novel GLCM-based 3D Texture Analysis software in terms of its input parameters in order to maximize the early prediction of knee osteoarthritis from 3D DESS MR images. 20 subjects (10 control subjects; 10 progressor subjects) containing image data from baseline and from a 36-month-follow-up were extracted from the Osteoarthritis Initiative database and used as the study dataset. Multiple sets of 3D Texture Analysis were conducted incorporating 22 static and dynamic grey level quantization schemes, 6 bin quantization schemes and 4 offset settings. Cliff’s delta was calculated to measure the effect size between the patient cohorts. Multilayer perceptron, Naïve Bayes and Support Vector Machines were implemented to classify the patients into their respective cohorts and estimate the robustness of the 3D Texture Analysis outputs. The predictions were done using only the baseline data, where all patients showed no signs of osteoarthritis. Maximum achieved robustness was 87%. The 3D Texture Analysis was found to have a high potential for the early prediction of knee osteoarthritis based on the GLCM features and the results outlined the importance of the software’s input parameters

Effects of Fish Populations on Pacific Loon (Gavia pacifica) and Yellow-billed Loon (G. adamsii) Lake Occupancy and Chick Production in Northern Alaska

  Predator populations are vulnerable to changes in prey distribution or availability. With warming temperatures, lake ecosystems in the Arctic are predicted to change in terms of hydrologic flow, water levels, and connectivity with other lakes. We surveyed lakes in northern Alaska to understand how shifts in the distribution or availability of fish may affect the occupancy and breeding success of Pacific (Gavia pacifica) and Yellow-billed Loons (G. adamsii). We then modeled the influence of the presence and abundance of five fish species and the physical characteristics of lakes (e.g., hydrologic connectivity) on loon lake occupancy and chick production. The presence of Alaska blackfish (Dallia pectoralis) had a positive influence on Pacific Loon occupancy and chick production, which suggests that small-bodied fish species provide important prey for loon chicks. No characteristics of fish species abundance affected Yellow-billed Loon lake occupancy. Instead, Yellow-billed Loon occupancy was influenced by the physical characteristics of lakes that contribute to persistent fish populations, such as the size of the lake and the proportion of the lake that remained unfrozen over winter. Neither of these variables, however, influenced chick production. The probability of an unoccupied territory becoming occupied in a subsequent year by Yellow-billed Loons was low, and no loon chicks were successfully raised in territories that were previously unoccupied. In contrast, unoccupied territories had a much higher probability of becoming occupied by Pacific Loons, which suggests that Yellow-billed Loons have strict habitat requirements and suitable breeding lakes may be limited. Territories that were occupied had high probabilities of remaining occupied for both loon species.  Les populations de prédateurs sont vulnérables aux changements de répartition ou de disponibilité des proies. En raison du réchauffement des températures, on prévoit que les écosystèmes lacustres de l’Arctique changeront pour ce qui est du régime hydrologique, des niveaux d’eau et de la connectivité avec d’autres lacs. Nous avons examiné des lacs du nord de l’Alaska pour comprendre comment les changements en matière de répartition ou de disponibilité des poissons peuvent avoir des incidences sur le taux d’occupation et sur le succès de reproduction du huart du Pacifique (Gavia pacifica) et du huart à bec blanc (G. adamsii). Ensuite, nous avons modélisé l’influence de la présence et de l’abondance de cinq espèces de poissons de même que les caractéristiques physiques de lacs (comme la connectivité hydrologique) par rapport au taux d’occupation lacustre des huarts et à la production d’oisillons. La présence du dallia (Dallia pectoralis) avait une influence positive sur l’occupation et la production d’oisillons chez le huart du Pacifique, ce qui suggère que les espèces de poissons au petit corps constituent une proie importante pour les oisillons. Aucune caractéristique de l’abondance des espèces de poissons n’a eu d’influence sur l’occupation lacustre du huart à bec blanc. L’occupation du huart à bec blanc a plutôt été influencée par les caractéristiques physiques des lacs qui contribuent aux populations de poissons persistantes, comme la taille du lac et la proportion du lac qui ne gelait pas en hiver. Toutefois, aucune de ces variables n’a exercé d’influence sur la production d’oisillons. La probabilité qu’un territoire inoccupé devienne occupé par le huart au bec blanc au cours d’une année subséquente était faible, et aucun oisillon huart n’a été élevé avec succès dans des territoires d’oisillons anciennement inoccupés. En revanche, les territoires inoccupés avaient une beaucoup plus grande probabilité de devenir occupés par les huarts du Pacifique, ce qui suggère que les huarts à bec blanc ont des exigences strictes en matière d’habitat et que le nombre de lacs convenant à la reproduction risque d’être limité. Les territoires qui étaient occupés avaient de fortes probabilités de rester occupés par les deux espèces de huarts

VIRUSES OF SOME GARLIC ECOTYPES IN CROATIA

Recent, there is increasing demand for autochthonous ecotypes of garlic (Allium sativum L.) in Croatia. Many local ecotypes of garlic are developed due to specific environmental conditions and producer's selection. However, the average yield of garlic is not in the European average range, since the classical vegetative propagation from cloves usually results with virus infections that cause significant yield reduction. Viruses are considered significant garlic’s pathogens. The research was set up to determine infection rate in plant material of different garlic ecotypes grown from cloves in different regions. Plants were collected from commercial fields in Zadar County (coastal part of Croatia) and Vukovar-Srijem County (eastern Croatia) and were tested by enzyme-linked immunosorbent assay (ELISA) on the presence of three viruses: Onion yellow dwarf virus (OYDV), Leek yellow stripe virus (LYSV) and Garlic common latent virus (GCLV). As a potential source ofantigen leaf tissue was used and tests were conducted according to manufacturer’s instructions (Bioreba AG, Switzerland). In plants from Zadar County dominant was OYDV, followed by GCLV and LYSV. All tested plants originating from Vukovar-Srijem County were infected with three tested viruses. Out of 316 analyzed plants only 4 (1.3%) showed to be free from viruses included in survey. Plants infected with OYDV showed symptoms of leaf yellowing and reduced growth, while those infected with LYSV expressed yellow stripes. Symptoms were most evident at the beginning of vegetation. Due to high infection rate, deteriorated sanitary status, and increased interest in use and production of local garlic ecotypes, work on sanitary selection will be important part of revitalization program

YBa2Cu3O7−δ films: Calculation of the thermal conductivity and phonon mean‐free path

We estimate the phonon mean‐free path (mfp) in YBa2Cu3O7−δ by performing a theoretical fitting procedure on bulk single‐crystal data. This analysis indicates that the mfps of the phonons that are most responsible for the transport of heat are much longer than would be predicted from kinetic theory. These values are incorporated into a recently proposed treatment of the size effect to provide an estimate of the thermal conductivity of YBa2Cu3O7−δ films.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70503/2/JAPIAU-72-10-4788-1.pd

How should we interpret the two transport relaxation times in the cuprates ?

We observe that the appearance of two transport relaxation times in the various transport coefficients of cuprate metals may be understood in terms of scattering processes that discriminate between currents that are even, or odd under the charge conjugation operator. We develop a transport equation that illustrates these ideas and discuss its experimental and theoretical consequences.Comment: 19 pages, RevTeX with 8 postscript figures included. To appear in ``Non Fermi Liquid Physics'', J. Phys:Cond. Matt. (1997

Concept for a Time-of-Flight Small Angle Neutron Scattering Instrument at the European Spallation Source

A new Small Angle Neutron Scattering instrument is proposed for the European Spallation Source. The pulsed source requires a time-of-flight analysis of the gathered neutrons at the detector. The optimal instrument length is found to be rather large, which allows for a polarizer and a versatile collimation. The polarizer allows for studying magnetic samples and incoherent background subtraction. The wide collimation will host VSANS and SESANS options that increase the resolution of the instrument towards um and tens of um, respectively. Two 1m2 area detectors will cover a large solid angle simultaneously. The expected gains for this new instrument will lie in the range between 20 and 36, depending on the assessment criteria, when compared to up-to-date reactor based instruments. This will open new perspectives for fast kinetics, weakly scattering samples, and multi-dimensional contrast variation studies.Comment: 18 pages, 10 figure

Thermal conductivity of Tl2Ba2Ca2Cu3O10 ceramics from 300 K down to 0.1 K

Thermal conductivity, [varkappa], of two ceramic samples of Tl2Ba2Ca2Cu3O10 has been measured over a temperature range from 300 K down to 0.1 K. At high temperatures, the data show features similar to the thermal conductivity of Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O ceramics in both the magnitude and the temperature dependence. Specifically, a sudden increase in the thermal conductivity is observed at the onset of a superconducting transition near 120 K culminating in a pronounced maximum of [varkappa] around 75 K and an eventual rapid decrease of the thermal conductivity at lower temperatures. From 5 K down to 0.1 K we observe the thermal conductivity to decrease with an average power law exponent between 2.4 and 2.5. Such a temperature dependence is comparable with that for sintered Bi-Sr-Ca-Cu-O samples, but differs from the quadratic variation typical for Bi-Sr-Ca-Cu-O single crystals and the T-linear asymptotic behavior characteristic of Y-Ba-Cu-O and La-Sr-Cu-O ceramics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29278/1/0000337.pd