A hierarchical anti-Hebbian network model for the formation of spatial cells in three-dimensional space.

Three-dimensional (3D) spatial cells in the mammalian hippocampal formation are believed to support the existence of 3D cognitive maps. Modeling studies are crucial to comprehend the neural principles governing the formation of these maps, yet to date very few have addressed this topic in 3D space. Here we present a hierarchical network model for the formation of 3D spatial cells using anti-Hebbian network. Built on empirical data, the model accounts for the natural emergence of 3D place, border, and grid cells, as well as a new type of previously undescribed spatial cell type which we call plane cells. It further explains the plausible reason behind the place and grid-cell anisotropic coding that has been observed in rodents and the potential discrepancy with the predicted periodic coding during 3D volumetric navigation. Lastly, it provides evidence for the importance of unsupervised learning rules in guiding the formation of higher-dimensional cognitive maps

Low temperature synthesis and characterization of LPCVD silicon dioxide films using diethylsilane

Diethylsilane (DES) has been used as a precursor to produce silicon dioxide films by low pressure chemical vapor deposition. These films were synthesized in the temperature range of 350 to 475°C thus allowing the use of the material as an intermetal dielectric or as a top layer passivation coating in microelectronic devices. In that process, the growth rate was observed to follow an Arrhenius behavior yielding an activation energy of 10 kcal/mol. The growth rate was also observed to increase with higher pressure and to vary as a function of the square root of the DES flow rate and O2/DES ratio. In both the pressure and the O2/DES ratio studies, there were points of abrupt cessation in deposition. The density of the films was measured to be close to 2.2 g/cm3 regardless of deposition conditions. RBS measurements revealed the absence of incorporated carbon and a near stochiometric composition of SiO2.2. The dielectric breakdown strength of an SiO2 film deposited at 400 °C was found to be 2 MV/cm. Infrared spectra of the films showed the usual Si-0 bond stretching and bond bending absorption bands centered at 1060, 810, and 440 cm-1. Si-H bending band at 880 cm-1 was also observed in SiO2 films prepared under certain processing conditions. The refractive index of the films was found to be at 1.46 independent of deposition temperature

Modeling the development of cortical responses in primate dorsal (“where”) pathway to optic flow using hierarchical neural field models

Although there is a plethora of modeling literature dedicated to the object recognition processes of the ventral (“what”) pathway of primate visual systems, modeling studies on the motion-sensitive regions like the Medial superior temporal area (MST) of the dorsal (“where”) pathway are relatively scarce. Neurons in the MST area of the macaque monkey respond selectively to different types of optic flow sequences such as radial and rotational flows. We present three models that are designed to simulate the computation of optic flow performed by the MST neurons. Model-1 and model-2 each composed of three stages: Direction Selective Mosaic Network (DSMN), Cell Plane Network (CPNW) or the Hebbian Network (HBNW), and the Optic flow network (OF). The three stages roughly correspond to V1-MT-MST areas, respectively, in the primate motion pathway. Both these models are trained stage by stage using a biologically plausible variation of Hebbian rule. The simulation results show that, neurons in model-1 and model-2 (that are trained on translational, radial, and rotational sequences) develop responses that could account for MSTd cell properties found neurobiologically. On the other hand, model-3 consists of the Velocity Selective Mosaic Network (VSMN) followed by a convolutional neural network (CNN) which is trained on radial and rotational sequences using a supervised backpropagation algorithm. The quantitative comparison of response similarity matrices (RSMs), made out of convolution layer and last hidden layer responses, show that model-3 neuron responses are consistent with the idea of functional hierarchy in the macaque motion pathway. These results also suggest that the deep learning models could offer a computationally elegant and biologically plausible solution to simulate the development of cortical responses of the primate motion pathway

The study on post-operative wound infections at Vizianagaram in Andhra Pradesh, India

Background: In most of the people post-operative wound infections are responsible for major complications such as cost, morbidity, mortality and duration of hospital stay related to surgeries. Objectives of the study were to demonstrate the incidence of post-operative wound infections at MIMS (Maharagah’s Institute of Medical Sciences, Vizianagaram.Methods: A cross sectional study has been carried out to know the incidence of post-operative wound infection The study was conducted in MIMS (Maharagah’s Institute of Medical Sciences). The study population was enrolled after fulfilling the selection criteria from General Surgery 100 patients (both elective and emergency surgeries) were selected using randomized technique.Results: Out of 100 cases in the study 17 were positive for post-operative wound infection and out of which 10 were mild infections, 9 cases were moderate infections and 3 were severe infections including 1 burst abdomen. Coagulase positive Staph aureus was isolated in 10 out 40. Over all infection rate in the study was 13.58%.Conclusions: The study clearly depicted the changing pattern of wound infection toward mixed infection. A larger study with substantial number of patients will confirm the findings of this study

Prognostication of Unseen Objects using Zero-Shot Learning with a Complete Case Analysis

Generally, for a machine learning model to perform well, the data instances on which the model is being trained have to be relevant to the use case. In the case of relevant samples not being available, Zero-shot learning can be used to perform classification tasks. Zero-shot learning is the process of solving a problem when there are no examples of that problem in the phase of training. It lets us classify target classes on which the deep learning model has not been trained. In this article, Zero-shot learning is used to classify food dish classes through an object recognition model. First, the data is collected from Google Images and Kaggle. The image attributes are then extracted using a VGG16 model. The image attributes belonging to the training categories are then used to train a custom-built deep learning model. Various hypermeters of the model are tuned and the results are analyzed in order to get the best possible performance. The image attributes extracted from the zero-shot learning categories are used to test the model after the training process is completed. The predictions are made by comparing the vectors of the target class with the training classes in the Word2Vec space. The metric used to evaluate the model is Top-5 accuracy which indicates whether the expected result is present in the predictions. A Top-5 accuracy of 92% is achieved by implementing zero-shot learning for the classification of unseen food dish images

Study of incidence in between benign and malignant tumors of solitary thyroid nodule

Background: Accurate imaging characterization of a solitary thyroid nodule has been clearly problematic. The purpose of this study was to evaluate the role of the apparent diffusion coefficient (ADC) values in the differentiation between malignant and benign solitary thyroid nodules. Objective of the study was to study the clinco-pathological correlation of solitary thyroid nodule and the incidence of malignancy.Methods: The study was conducted in MIMS (Maharagah’s Institute of Medical Sciences). The study population was enrolled after fulfilling the selection criteria from OPD (Out Patient Department) of General Surgery. A total of 50 cases were studied who presented with complaint of thyroid swelling which was clinically confirmed as solitary thyroid nodule. Importance was given to detailed history; duration of swelling, pressure symptoms, and symptoms associated illnesses, previous exposure to neck irradiation, history of anti-thyroid drug use, positive family history. A detailed local examination was done in all cases followed by systemic examination.Results: Out of 50 cases 10 cases were found to have malignant lesions with remaining 40 cases being benign lesions. The malignant nodules were significantly lower than those of benign ones (P = 0.0001). There were no significant differences between the mean ADC values of various malignant thyroid nodules, but there were significant differences between the subtypes of benign thyroid nodules (P = 0.0001).Conclusions: The ADC value is a new promising non-invasive approach used for differentiating malignant from benign solitary thyroid nodules. The incidence of malignancy in solitary thyroid nodule is quite high. This warrants education to people to consult physicians for early diagnosis and adequate treatment without being passive as most of these swellings are asymptomatic for long duration

Role of non-lipid risk factors like hs-CRP, uric acid and thyroid stimulating hormone in metabolic syndrome

Background: Metabolic syndrome is the cluster of diseases which arises due to excess of plasma glucose, cholesterol, fatty acids, blood pressure and obesity. The role of lipids in the development of MetS had been extensively studied. Though some non-lipid factors like hsCRP, uric acid and TSH level also remain elevated in the serum of the MetS patients, the role of these non-lipid risk factors remain incompletely understood. The objective of this study was to investigate which of these factors better predicts Mets, in order to help prevention and early detection of MetS and its associated type 2 diabetes mellitus and cardiovascular diseases. Aim and objectives was to study the significance of serum highly sensitive C-reactive protein (hs-CRP), serum uric acid (SUA) and thyroid stimulating hormone (TSH) levels in metabolic syndrome.Methods: A total of four hundred and fifty subjects (211 men and 239 women) aged ≥35 years attending the hospital were divided into three groups based on the components level of MetS as control (CS), normal (MS) and severe (SMS) MetS groups. Their fasting blood sample were taken and analyzed for the serum hs-CRP, uric acid and TSH levels. The result showed that the mean hs-CRP and uric acid levels were significantly higher in Metabolic Syndrome group (MS) and in Severe Metabolic Syndrome group (SMS) when compared to control group. But the mean TSH levels were more in MS group and in SMS group than the control which was statistically not significant. The analysis of relative significance of these risk factors showed that serum hs-CRP level had a positive linear correlation with the severity of MetS whereas, the TSH level was significantly high only in SMS and the uric acid level was not correlated with the MetS.Results: Our study revealed that type II (absence of sutural bones) was commoner than type I (presence of type I) asterion. The asterion was 4.82±0.58 cm from tip of the mastoid process on the right side and 4.70±0.70 cm on the left. It was greater in males than in females, p value being statistically significant (P = 0.00 and P = 0.02 for right and left sides respectively). The distance of asterion from supramastoid crest was 4.22±0.73 cm on the right and 4.23±0.58 cm on the left. The distance in males was more than in females. The P value 0.00 was statistically significant on the right side. Regarding the position of the asterion in relation to transverse sinus, it was on the transverse sinus in 62% cases, below it in 32% and above in 6%.Conclusions: In the present study, there was higher mean serum hs-CRP level in patients with metabolic syndrome which showed a linear increase with increasing number of components of the metabolic syndrome. Though available literature indicated that hyperuricemia adult subjects tend to develop MetS more frequently our findings showed this increase was not dependent on the severity of MetS. Also, significantly high TSH levels were found only in severe MetS suggest that as per this study the serum hs-CRP values may be consider as the diagnostic criteria for metabolic syndrome and helps to improve future prediction of development of type 2 DM and cardiovascular diseases

Development of a device for measurement and control of top product composition in a distillation column

The objectives of this investigation were to: • Develop a capacitance measuring device that can be used for measuring composition of ethanol-water mixtures. • Implement this measurement technique on a laboratory clistillation column for top product composition measurement and control. • Compare the results obtained in this manner with previously used inferred measurements by temperature. Experiments were conducted to calibrate the capacitance cell ie, to obtain a relation between composition of an ethanol and water mixture and the output of the capacitance cell. Open loop tests were executed on the distillation column to determine if the capacitance device had any negative influence on measurement compared to composition measurements via temperature. Top product composition control using the capacitance cell under dosed loop conditions was also tested, to observe the capacitance cell's performance. The capacitance cell gave repeatable readings during the calibration procedure. In the open loop tests, process models were obtained for control purposes and no negative influence was observed. The capacitance cell's closed loop responses were observed to be satisfactory. It was simple to construct, easy to operate and proved to be a relatively inexpensive device. In the final analysis, the capacitance cell proved to be a useful device in direct measurements of composition of binary mixtures, and offers scope for further development in its application to the control of top product composition in distillation columns of industrial scale.Dissertation (M Eng (Control Engineering))--University of Pretoria, 2006.Chemical Engineeringunrestricte