Tensor Analysis and Fusion of Multimodal Brain Images

Current high-throughput data acquisition technologies probe dynamical systems with different imaging modalities, generating massive data sets at different spatial and temporal resolutions posing challenging problems in multimodal data fusion. A case in point is the attempt to parse out the brain structures and networks that underpin human cognitive processes by analysis of different neuroimaging modalities (functional MRI, EEG, NIRS etc.). We emphasize that the multimodal, multi-scale nature of neuroimaging data is well reflected by a multi-way (tensor) structure where the underlying processes can be summarized by a relatively small number of components or "atoms". We introduce Markov-Penrose diagrams - an integration of Bayesian DAG and tensor network notation in order to analyze these models. These diagrams not only clarify matrix and tensor EEG and fMRI time/frequency analysis and inverse problems, but also help understand multimodal fusion via Multiway Partial Least Squares and Coupled Matrix-Tensor Factorization. We show here, for the first time, that Granger causal analysis of brain networks is a tensor regression problem, thus allowing the atomic decomposition of brain networks. Analysis of EEG and fMRI recordings shows the potential of the methods and suggests their use in other scientific domains.Comment: 23 pages, 15 figures, submitted to Proceedings of the IEE

Scalars, Vectors and Tensors from Metric-Affine Gravity

The metric-affine gravity provides a useful framework for analyzing gravitational dynamics since it treats metric tensor and affine connection as fundamentally independent variables. In this work, we show that, a metric-affine gravity theory composed of the invariants formed from non-metricity, torsion and curvature tensors can be decomposed into a theory of scalar, vector and tensor fields. These fields are natural candidates for the ones needed by various cosmological and other phenomena. Indeed, we show that the model accommodates TeVeS gravity (relativistic modified gravity theory), vector inflation, and aether-like models. Detailed analyses of these and other phenomena can lead to a standard metric-affine gravity model encoding scalars, vectors and tensors.Comment: 13 p

Constraints on North Anatolian Fault Zone Width in the Crust and Upper Mantle From S Wave Teleseismic Tomography

We present high-resolution S wave teleseismic tomography images of the western segment of the North Anatolian Fault Zone (NAFZ) in Turkey using teleseismic data recorded during the deployment period of the Dense Array for Northern Anatolia array. The array comprised 66 stations with a nominal station spacing of 7 km, thus permitting a horizontal and vertical resolution of approximately 15 km. We use the current S wave results with previously published P wave teleseismic tomography to produce maps of relative VP/VSanomalies, which we use to highlight the difference in overall composition of the three terranes separated by the northern (NNAF) and southern branches of the NAFZ. Our results show a narrow S wave low-velocity anomaly beneath the northern branch of the NAFZ extending from the upper crust, where it has a width of ∼10 km, to the lower crust, where it widens to ∼30 km. This low-velocity zone most likely extends into the upper mantle, where we constrain its width to be ≤ 50 km and interpret it as indicative of localized shear beneath the NNAF; this structure is similar to what has been observed for the NAFZ west of 32°, and therefore, we propose that the structure of the NNAF is similar to that of the NAFZ in the east. The southern branch of the NAFZ does not show a very strong signature in our images, and we conclude that it is most likely rooted in the crust, possibly accommodating deformation related to rotation of the Armutlu/Almacik Blocks situated between the two NAFZ branches

Effects of Thiamethoxam on Vespula Germanica (F.) (Hymenoptera: Vespidae)

Damage of pesticides used in agriculture on non-target organisms (except honey bees) is not sufficiently considered and neglected. Studies showed that wild bees, like honey bees, were also affected by pesticides. Wild bee species should also be protected because of their importance in pollination and biological control and also in order to protect biodiversity. Effects of pesticides on wild bees should be investigated without delay and precautions should be taken to protect the generations of wildlife. In addition, while increasing the agricultural areas, habitat for wild pollinators should be established.In this study, effect of Thiamethoxam, an agriculturally active agent in the neonicotinoid group, commonly used in agriculture fields, on the European wasp (Vespula germanica) was investigated. For this purpose, 2 molar carnation-flavored syrup in a petri dish was placed in a field where wild bees are frequent, and wild bees had got accustomed there. Trial doses were prepared with thiamethoxam dose commonly used in agricultural areas (15 ml/100 L water) and 50% dilutions of this dose (15.00, 7.50, 3.75, 1.87, 0.93, 0.46, 0.23, 0.12, 0.06 ml/100 L water) and fed in 2 molar syrup. Those who returned to the carnation petri dish after feeding were recorded at the 1st, 4th and 24th hours.At the end of the study, bees fed with 15.00, 7.50, and 3.75 ml / 100 L doses of the pesticide all died. One hour after pesticide ingestion, 84.73% of the control group and 13.33% of the bees fed with 1.87 ml / 100L dose, were alive and returned to the syrup petri dish

Neurovascular relationship between abducens nerve and anterior inferior cerebellar artery

We aimed to study the neurovascular relationships between the anterior inferior cerebellar artery (AICA) and the abducens nerve to help determine the pathogenesis of abducens nerve palsy which can be caused by arterial compression. Twenty-two cadaveric brains (44 hemispheres) were investigated after injected of coloured latex in to the arterial system. The anterior inferior cerebellar artery originated as a single branch in 75%, duplicate in 22.7%, and triplicate in 2.3% of the hemispheres. Abducens nerves were located between the AICAs in all hemispheres when the AICA duplicated or triplicated. Additionally, we noted that the AICA or its main branches pierced the abducens nerve in five hemispheres (11.4%). The anatomy of the AICA and its relationship with the abducens nerve is very important for diagnosis and treatment. (Folia Morphol 2010; 69, 4: 201-203

A qualitative research method on factors affecting housing career

Konut kavramının çok boyutlu olması, çeşitli disiplinlerden birçok bilim insanının farklı bakış açıları ve farklı yöntemlerle konut konusuna yaklaşmalarına neden olmuştur. Konut çalışmaları, sosyal, ekonomik, politik, demografik bağlamda birbirleri ile etkileşim içinde olan farklı konu alanlarını içermektedir. Bununla birlikte mevcut çalışmalar daha bütünleşik ve disiplinler arası bir yaklaşıma ihtiyaç duyulduğunu göstermektedir. Bu nedenle çalışmada hanehalkı ve konut pazarı dinamiklerinin bütünleşik modelini geliştirmek, bir konut kariyeri modeli oluşturmak hedeflenmiştir. Bu amaçla kapsamlı bir literatür araştırması ve İstanbul ili çerçevesinde bir alan çalışması yapılmıştır. Çalışmanın zenginleşmesi ve modelin geliştirilmesi amacıyla alan araştırmasında, nitel araştırma yöntemlerinden derinlemesine görüşme tekniği ve görüşme formu yaklaşımı kullanılmıştır. Görüşme tekniği özellikle araştırmacı çalışmalar ve ‘nasıl’, ‘neden’ sorularını yanıtlamada tercih edilmektedir. Yöntem, çalışmada yaşamlarının farklı dönemlerindeki farklı yapıda ve özellikteki hane halklarının konut kariyerlerini, deneyimlerini, konut seçim ve kararlarını açıklamak, yerleşim birimi, konut, kişilerin yaşam biçimi gibi faktörlerin neden ve nasıl hane halklarının kararlarını, tercihlerini etkilediğinin cevabını bulmak amaçlı kullanılmıştır. Araştırma sonucu oluşturulan genel temalar ve önermeler yardımı ile model geliştirilmiştir. Bu makalede çalışmanın yöntemi üzerinde durulacaktır. Anahtar Sözcükler: Konut kariyeri, araştırma yöntemleri, nitel araştırma yöntemi.Housing has been studied from many different perspectives in which diversity could be seen in approaches. Housing studies include different areas which are integrated each other in social, politic, economic and demographic contexts. While explaining housing demand, the term of 'housing career' is used preferentially since it is a multi-dimensional concept. Housing career is used in order to explain the changes in housing consumption in connection with the residential mobility. The concept which includes topics such as resources, access to resources, organizations, housing tenure, physical situation of the dwellings, location and cost enables to build up a connection between mobility and life-cycle of households. It helps to understand and analyse housing demands of different households at different life-cycle stages. Studying housing careers of households is also affective in displaying how housing demand is directed and changed. There are various models consisting of various approaches in the literature, which explain housing demand and housing career. However, existing studies reveal that, a more integrative and interdisciplinary approach is required in which socio-cultural, geographical, physical, economic and psychological dimensions are interrelated. Hence, in this study, the objective is to find how housing demand is changed and directed by developing an integrated and interdisciplinary model of households and housing market dynamics. As the concept of housing career enables to look at residential mobility and housing choice from a broader and integrated perspective, this term is particularly chosen to establish the model. The model aims to deal with household dynamics in an urban area by taking into consideration economic, political and social developments, housing demand behaviours simultaneously. To this end, a comprehensive literature review was carried out, and a field study was performed within Istanbul. The field study was built on qualitative research approach, and a semi-structured interview method was chosen. Content analyse method was used in analysing the text created upon transcribing the interviews of the households. The model was developed with the help of general themes and hypothesises formed according to the research. In housing literature, qualitative research methods didn't attract as much attention as the quantitative research methods due to the general approach adopted by the researches for a long time. Many studies were carried out on similar research topics with a range of methodological approaches such as analysis of large-scale data-sets, survey work and case studies. The dominant approach in the housing literature has been to prioritize quantitative methods. However, qualitative research methods provide more detailed understanding of behaviour attitudes and experiences of individuals and help answering the questions such as "how" and "why". Qualitative research is an inquire process of understanding on distinct methodological traditions of inquiry that explore a social or human problem. As the PhD study aims to answer the question how housing demand is directed and changed; and also aims to describe the factors and processes that have impacts on households, to explain households' experiences, housing choices and housing careers and to determine how households perceive their resources, constraints, contexts and how these perceptions, personal behaviours and life styles are effective in forming housing careers, qualitative research method is found to be the best appropriate method to use. During the field study, in-depth interview technique was used. In-depth interview is a qualitative research technique which enables the highest efficiency in gathering information about personal subjects, learning about the perceptions and emotions and understanding personal opinions by reducing the impact of group. The interviews were designed to describe a sample of households, to explore the behavioural and psychological aspects of the households and the way the households are affected from local and global developments. A semi-structured interview method was adopted since this kind of format with open-ended questions is most suitable when the emphasis is on the exploration rather than hypothesis testing. Content analyse method was used in analysing the text which was created after transcribing the interviews of the households. The model was developed with the help of the general themes and hypothesises which were formed according to the research. Keywords: Housing career, research methods, qualitative research method.

Seismic tomography of the North Anatolian Fault: New insights into structural heterogeneity along a continental strike-slip fault

Knowledge of the structure of continental strike-slip faults within the lithosphere is essential to understand where the deformation occurs and how strain localizes with depth. With the aim to improve the constraints on the lower crust and upper mantle structure of a major continental strike-slip fault, we present a high-resolution teleseismic tomography of the North Anatolian Fault Zone (NAFZ) in Turkey. Our results highlight the presence of a relatively high velocity body between the two branches of the fault and significant along-strike variations in the NAFZ velocity structure over distances of ~20 km. We interpret these findings as evidence of laterally variable strain focussing caused by preexisting heterogeneity. Low velocities observed in the crust and upper mantle beneath the NAFZ support the presence of a narrow shear zone widening in the upper mantle, where we constrain its width to be ~50 km.Major funding was provided by the UK Natural Environment Research Council (NERC) under grant NE/I028017/1. Equipment was provided and supported by the NERC Geophysical Equipment Facility (SEIS-UK). This project is also supported by Bogaziçi University Scientific ˘ Research Projects (BAP) under grant 6922 and Turkish State Planning Organization (DPT) under the TAM project, number 2007K120610