Origin of thyroid arteries in a Kenyan population

Introduction: The thyroid gland receives blood supply predominantly from paired superior and inferior thyroid arteries. The superior thyroid artery originates from external carotid while the inferior thyroid artery is a branch of thyrocervical trunk. Unusual origins of superior thyroid artery include common carotid and cervical part of internal carotid arteries while those for the inferior thyroid artery are subclavian, common carotid or the vertebral arteries. These origins vary between populations. Knowledge of variant anatomy of these arteries is important in surgical procedures within the neck. This study describes variant origin of the thyroid arteries in a Kenyan population.Materials and Methods: Fifty formalin fixed cadavers from the Department of Human Anatomy, University of Nairobi were available for the study. Skin incisions were made from the chin to the supra-sternal notch, along the clavicle to the acromion and then to the mastoid process. Skin flaps and platysma muscle were refl ected for exposure of the anterior triangle of the neck. The sternocleidomastoid was cut close to its origins on the clavicle and reflected superiorly. The strap muscles were transected and reflected to expose the thyroid gland lying within the visceral fascia. The dissection field was cleaned by blunt and sharp dissection to expose the gland. The two thyroid arteries were identified from either pole of the gland and traced to their respective origins.Data Analysis: Data was coded, tabulated and analysed using SPSS 16.0 for windows® (SPSS Inc., Chicago, Illinois) for percentages and frequencies of the observed variations in origin and nerve relations. Results were presented in tables and macrographs.Results: Superior thyroid artery originated from external carotid and common carotid artery in 74.4% and 25.6 % of cases respectively. The right side displayed a higher frequency of origin from the common carotid artery. The inferior thyroid artery arose from thyrocervical trunk in 87.5% and from subclavian artery in 12.5% of cases. There was a higher incidence of the inferior thyroid artery originating from the subclavian on the left than the right side.Conclusion: Over 25% of superior thyroid arteries and 11 % of inferior thyroid arteries show variant origins. The common carotid and subclavian arteries were the most frequent variant sites of origin for superior and inferior thyroid arteries respectively. Bilateral asymmetry was observed. Neck surgeons should be aware of these variations during ligation and selective embolisation of thyroid arteries to avoid complications during surgery

Relation of the external laryngeal nerve to superior thyroid artery in an African population

The external laryngeal nerve runs parallel to superior thyroid artery and later crossing the artery either above or below the upper pole of the thyroid gland. This relatively high anatomic variability demonstrates inter-population differences. However, datum among the Kenyan population is lacking. Knowledge of normal and variant anatomy of these structures is important in surgical procedures within the neck. This study therefore aimed at describing the variant anatomical relations of the superior thyroid artery and external laryngeal nerve for the Kenyan population. Twenty formalin fixed cadavers obtained from the Department of Human Anatomy, University of Nairobi were dissected to expose the thyroid gland, superior thyroid artery and external laryngeal nerve. The relation of the superior thyroid artery to the external laryngeal nerve was noted. The external laryngeal nerve crossed the superior thyroid artery within 1cm above the upper pole of the thyroid gland in 25% of cases and more than 1 cm in 75% of cases. The level at which the external laryngeal nerve crosses the superior thyroid artery displays variations among Kenyans warranting care during surgical procedures of the thyroid gland.Key words: Superior thyroid artery, Nerv

Classification of N=2 supersymmetric CFT_{4}s: Indefinite Series

Using geometric engineering method of 4D $\mathcal{N}=2$ quiver gauge theories and results on the classification of Kac-Moody (KM) algebras, we show on explicit examples that there exist three sectors of $\mathcal{N}=2$ infrared CFT$_{4}$s. Since the geometric engineering of these CFT$_{4}$s involve type II strings on K3 fibered CY3 singularities, we conjecture the existence of three kinds of singular complex surfaces containing, in addition to the two standard classes, a third indefinite set. To illustrate this hypothesis, we give explicit examples of K3 surfaces with H$_{3}^{4}$ and E$_{10}$ hyperbolic singularities. We also derive a hierarchy of indefinite complex algebraic geometries based on affine $A_{r}$ and T$$ algebras going beyond the hyperbolic subset. Such hierarchical surfaces have a remarkable signature that is manifested by the presence of poles.Comment: 12 pages, 2 figure

On the security of digital signature protocol based on iterated function systems.

A common goal of cryptographic research is to design protocols that provide a confidential and authenticated transmission channel for messages over an insecure network. Hash functions are used within digital signature schemes to provide data integrity for cryptographic applications. In this paper, we take a closer look at the security and efficiency of the digital signature protocol based on fractal maps. This new system can be expected to have at least the same computational security against some known attacks. A Diffie-Hellman algorithm is used to improve the security of the proposed protocol by generating the number of iteration that is used to find the attractor of the iterated function system, which is used to calculate the public key and the signature. The proposed algorithm possesses sufficient security against some known attacks applicable on finite field cryptosystems. They are considered as time consuming to be involved in solving non-linear systems numerically over the defined infinite subfield

Biometric identification using local iterated function

Biometric identification protocol has been received an increasing interest recently. It is a process that determines person identity by making use of their biometric features. A new biometric identification method is presented in this paper based on partial self-similarity that used to identify features within fingerprint images. This approach is already used in Fractal Image Compression (FIC) due to their ability to represent the images by a limited number of affine transformations, and its variation of scale, translation or rotation. These features give the recognition process high impact and good performance. To process data in a fingerprint image, it first converted into digital format using Optical Fingerprint Reader (OFR). The verification process is done by comparing these data with the server data. The system analysis shows that the proposed method is efficient in terms of memory and time complexity

A new public key cryptosystem based on IFS

Most public key encryption methods suffers from the inability to prove the difficulty of the algorithms, which summarizes under the category of mathematical problems that have inverses which are believed (but not proven) to be hard. The length and strength of the Cryptography keys are considered an important mechanism. The keys used for encryption and decryption must be strong enough to produce strong encryption. Fractals and chaotic systems have properties which have been extensively studied over the years, and derive their inherent complexity from the extreme sensitivity of the system to the initial conditions. In this paper a new cryptographic system based on Iterated Function Systems ( IFS) have been proposed to reduce the computation cost and increase the security for the public-key cryptography protocols. In the proposed public-key encryption algorithm, generate iterated function systems as a global public element, then its Hutchinson operator is used as a public key. To encrypt the plaintext with the receiver's public key we use one of the key agreement protocols to generate a shared private key that used to find the attractor of the IFS. The chaotic nature of the fractal functions ensures the security of the proposed public-key cryptosystem scheme

Fractal attractor based digital signature

Fractal theories are applied to enhance the efficiency and performance of cryptosystem due to their inherent complexity and mathematical framework. A new digital signature scheme based on Iterated Function System (IFS) is proposed, which can reduce computation cost and increase security of the system. The properties of the proposed system are discussed in detail

Choice drivers for quality-labelled food: A cross-cultural comparison on pdo cheese

This study aims at examining the consumers’ preferences and drivers affecting the choice of quality-labelled food products, i.e., protected designation of origin (PDO) labelled cheese. We applied the theory of planned behaviour (TPB) to analyse the purchase of Parmigiano Reggiano PDO and Comté PDO hard cheeses in Italy and France, respectively. A cross-sectional sample of 808 consumers (400 French and 408 Italian) completed a questionnaire. Structural equation modelling (SEM) indicated perceived behavioural control (PBC) and attitude to be significant predictors of intention to purchase PDO-labelled cheese in France and Italy. Subjective and moral norms affected intention in France. Intention significantly influenced the hard cheese purchase behaviour. The results confirm that the TPB model predicted the self-reported measure of behaviour more than the observed one, measured with a discrete choice experiment, in both countries. The TPB interrelationships varied between countries, suggesting that food systems operators and public authorities should carefully target their intervention to stimulate the demand of PDO-labelled products

Determinants of Foreign Direct Investment: New Granger Causality Evidence from Asian and African Economies

Previous studies on the determinants of foreign direct investment (FDI) have predominantly focused on developed and emerging economies. However, there seem to be few studies concentrating on a comparative analysis of vast African and Asian countries. This paper analysed drivers of foreign direct investments (FDI) to Asian and African economies using a panel dataset from 1980 to 2013.This study used Granger causality test, under vector error correction modelling (VECM) to test for causality among the variables. While the drivers of FDI inflows were measured using five dimensions as proposed by Anyanwu; the dependent variable, FDI inflows, was proxied by the ratio of FDI flows to gross domestic product (GDP). Findings revealed that variables manifesting the determinants of FDI inflows positively affected FDI into these continents. Specifically, factors such as trade openness, macroeconomic condition, infrastructural development, and monetary union have positive and significant effect on FDI to Asian economies. No significant relationship was found between FDI inflows and market size to the Asian continent during the study period. On the other hand, trade openness, macroeconomic condition, market size and infrastructural development have positive and significant effects on FDI inflows to African economies although there was no significant relationship between FDI inflows and monetary union to the African continent during the study period. In fact, there were bi-directional relationships between FDI inflows and some of the determinants in both continents. Theoretically, this model provides predictive implications on improved FDI inflows, given the activities of critical variables manifesting as determinants of FDI inflows

On the dilaton and the axion potentials

We extend the Vecchia-Veneziano-Witten (VVW) model of QCD in the chiral limit and for large colour number $N_c$, by introducing an effective dilaton-gluon coupling from which we derive both the axion and dilaton potentials. Furthermore, using a string inspired model, we determine a new interquark potential as a perturbative series in terms of the interquark distance $r$. Our potential goes beyond Dick one obtained in [8] and shares the same features as the Bian-Huang-Shen potential $V_{BHS}$ which depends only on odd powers of $r$ [22].Comment: 15 pages, Late