Bolstering Stochastic Gradient Descent with Model Building

Stochastic gradient descent method and its variants constitute the core optimization algorithms that achieve good convergence rates for solving machine learning problems. These rates are obtained especially when these algorithms are fine-tuned for the application at hand. Although this tuning process can require large computational costs, recent work has shown that these costs can be reduced by line search methods that iteratively adjust the stepsize. We propose an alternative approach to stochastic line search by using a new algorithm based on forward step model building. This model building step incorporates second-order information that allows adjusting not only the stepsize but also the search direction. Noting that deep learning model parameters come in groups (layers of tensors), our method builds its model and calculates a new step for each parameter group. This novel diagonalization approach makes the selected step lengths adaptive. We provide convergence rate analysis, and experimentally show that the proposed algorithm achieves faster convergence and better generalization in well-known test problems. More precisely, SMB requires less tuning, and shows comparable performance to other adaptive methods

Sex estimation in a contemporary Turkish population based on CT scans of the calcaneus

Building a reliable biological profile from decomposed remains depends heavily on the accurate estimation of sex. A variety of methods based on every single skeletal element have been developed over the years for different populations employing both osteological and virtual methods. The latter seem to be a reasonable alternative in countries lacking osteological reference collections. The current study used 3D virtual models of calcanei from CT scans of living adults to develop a sex estimation method for contemporary Turkish. Four hundred and twenty eight calcanei CT scans were analysed. The sample was divided in two subsamples: an original (N = 348) and a validation sample (N = 80) with similar distribution of males and females. Nine classical measurements were taken using the 3D models of the calcanei and two different statistical methods (Discriminant function analysis and Binary logistic regression) were used. Classification accuracy ranged from 82% to 98% for the validation sample and it was consistently high using any of the two methods. Sex bias seems to be lower for most of the logistic regression equations compared to the discriminant functions. These results, however, need further testing to be verified. Based on the results of this study we recommend the use of both methods for sex estimation from the measurements of the calcaneus bone in a Turkish population. (C) 2017 Elsevier B.V. All rights reserved

Knowledge, attitudes and misconceptions of primary care physicians regarding fever in children: a cross sectional study

<p>Abstract</p> <p>Background</p> <p>Fever is an extremely common sign in paediatric patients and the most common cause for a child to be taken to the doctor. The literature indicates that physicians and parents have too many misconceptions and conflicting results about fever management. In this study we aim to identify knowledge, attitudes and misconceptions of primary care physicians regarding fever in children.</p> <p>Methods</p> <p>This cross-sectional study was conducted in April-May 2010 involving primary care physicians (n=80). The physicians were surveyed using a self-administered questionnaire. Descriptive statistics were used.</p> <p>Results</p> <p>In our study only 10% of the physicians knew that a body temperature of above 37.2°C according to an auxiliary measurement is defined as fever. Only 26.2% of the physicians took into consideration signs and symptoms other than fever to prescribe antipyretics. 85% of the physicians prescribed antipyretics to control fever or prevent complications of fever especially febrile seizures. Most of the physicians (76.3%) in this study reported that the height of fever may be used as an indicator for severe bacterial infection. A great majority of physicians (91.3%) stated that they advised parents to alternate the use of ibuprofen and paracetamol.</p> <p>Conclusions</p> <p>There were misconceptions about the management and complications of fever. There is a perceived need to improve the recognition, assessment, and management of fever with regards to underlying illnesses in children.</p

Clinically relevant variations of the superior thyroid artery: an anatomic guide for surgical neck dissection

WOS: 000263525800001PubMed ID: 18754071The superior thyroid artery (STA) is the dominant arterial supply of the thyroid gland, upper larynx and the neck region. The knowledge of variations in possible patterns of origin, courses, and branching pattern of the STA is also important for surgical procedures in the neck region, such as emergency cricothyroidotomy, radical neck dissection, catheterization, reconstruction of aneurysm and carotid endarterectomy. The surgical anatomy of the STA was studied in 20 adult Anatolian preserved cadavers between the age of 40 and 70 years. The outer diameter of the STA origin was observed to be 3.53 +/- A 1.17 mm. The location of the origin of the STA according to the carotid bifurcation was evaluated as above (25%), below (35%) and at the same level (40%). The distribution patterns of the STA were classified into six types depending on the branching pattern. The outer diameter of the infrahyoid branch, superior laryngeal artery, sternocleidomastoid artery and cricothyroid branch at their origins were observed to be 1.13 +/- A 0.14, 1.42 +/- A 0.47, 1.54 +/- A 0.96 and 1.30 +/- A 0.41 mm, respectively. Typical and variant glandular branching patterns were observed in 85 and 15% of the specimens, respectively. The outer diameters of anterior, anteromedial, anterolateral and posterior glandular branches were measured as 2.05 +/- A 0.46, 1.41 +/- A 0.43, 1.51 +/- A 0.41 and 1.73 +/- A 0.53 mm, respectively. It is necessary to understand the surgical anatomy of the STA to carry out successful radical neck dissection and to minimize postoperative complications in a bloodless surgical field

Anatomical and surgical aspects of the lobes of the thyroid glands

WOS: 000293554500018PubMed ID: 21298390Variation in the descent of the thyroid gland and during fetal life and regression of the thyroglossal duct is associated with many variations in form of the mature gland. The shape and morphometric details of gland, its extension as the pyramidal lobe (PYR-L) and attachments of the levator glandulae thyroidea were studied in 40 cadavers. We categorized the shape of the thyroid into 12 types. The most frequent type was PYR-L with 22.5% which started from the left lobe and moved across by intercrossing the larynx. Horseshoe-shaped gland and the gland with separate lobes were the most frequently observed glandular shapes, with 17.5 and 20%, respectively. The incidences of the PYR-L and the levator glandulae thyroideae were 60 and 17.5%, respectively. The pyramidal lobe branched off more frequently from the left part of the isthmus (14 specimens) than from the right (5 specimens) or the midline (2 cases). Knowledge about the glandular landmarks and anatomic measurements around the thyroid will be helpful for the surgeon to constitute a simplification of the topographic anatomy, plan and decide on a safe approach to the thyroid gland, and to avoid postoperative complications

A study of the course of the internal carotid artery in the parapharyngeal space and its clinical importance

WOS: 000250442100017PubMed ID: 17638001The differences in the course and shape of the internal carotid artery (ICA) in the parapharyngeal space were investigated to determine the possible risks for serious hemorrhage during tonsillectomy, drainage of peritonsillar abscess, soft palate injuries, adenoidectomy and velopharyngeoplasty. The course of the ICA was studied in the parapharyngeal spaces of 50 adult cadavers. From each specimen, circumferential sections were obtained and they stained with hematoxylin - eosin and Verhoeff's elastic staining. The cervical course of the ICA showed no curvature in 70 cases; but in 25 cases it had a medial curve, and five cases showed kinking out of a total 100 dissected carotid sheaths. In two cases, kinking of the ICA was related to the pharyngeal wall. The histological examination of all kinking specimens demonstrated depletion and decreasing muscle tissue in tunica media and an increase was observed in vasa vasorum numbers in the tunica adventitia of ICA. The dissections and integrity losses were seen in tunica media and tunica adventitia. The vessel wall of histological structure change were detected in kinking specimens and lays the groundwork for the vessel wall to get easily harmed or torn either directly or indirectly by decreasing the elasticity and soundness of the wall. The transposition of the ICA artery in submucous position becomes important for otorhinolaryngologists when its aberrant course causes a widening in the retropharyngeal or parapharyngeal tissues and an impression on the pharyngeal wall. Curving and kinking of the ICA can constitue a risk factor for acute hemorrhage in routine surgical procedures, which are performed by inexperienced surgeons

Examination of the Heads of the Lateral Pterygoid Muscle on the Temporomandibular Joint

WOS: 000262838400057PubMed ID: 19165031The lateral pterygoid muscles (LPMs) function as a unit during precise mandibular positioning movements that occur during such activities as speech, singing, or playing musical instruments. The LPM has been the focus of an attempt to explain problems associated with the temporomandibular joint and anterior displacement of the meniscus of the joint. The aim of the study was to define the general morphology, describing the position and shape of the heads of the LPMs. In the course of dissection, the heads of the LPMs were noted, as well as the pattern, position of the origin and insertion, and course under 2.5x loupe magnification in 25 adult male human cadavers. The LPM has the general form of an irregular pyramid that narrows progressively toward the front. As a result of the macroscopic examination, the LPM was found to originate, with 3 heads as the Superior LPM (SLIM), the inferior LPM (ILPM), and inner LPM. It was realized that the ILPM width was 3 times more than that of the SLPM. The SLPM ending fibers of LPM had a more tendinous structure compared with the ILPM ending fibers. The SLPM and ILPM were observed as being adhered mostly to the pterygoid fovea. The study has shown that the muscle has atypical penniform structure made up of 8 tendinous layers that were particularly well developed. It is an indisputable fact that the success in surgical strategy and planning mainly relies on the surgeon's knowledge of the variable origins and insertions of the LPM.Research and Application Center of Science and Technology, Ege University, TurkeyEge UniversityThis investigation was supported by the Research and Application Center of Science and Technology, Ege University, Turkey