Elliptic Fourier analysis of crown shapes in Quercus petraea trees

Shape is a fundamental morphological descriptor, significant in taxonomic research as well as in ecomorphology, one method of estimation being from digitally processed images. In the present study, were analysed shapes of Q. petraea crowns, pertaining to five different stem diameter classes, from three similar stands. Based on measurements on terrestrial digital vertical photos, crown size analysis was performed and correlations between crown and stem variables were tested. Linear regression equations between crown volumes and dbh, and crown volumes and stem volumes were derived, explaining more than half of data variability. Employment of elliptic Fourier analysis (EFA), a powerful analysis tool, permitted the extraction of the mean shape from crowns, characterized by high morphological variability. The extracted, most important, coefficients were used to reconstruct the average shape of the crowns, using Inverse Fourier Transform. A mean shape of the crown, corresponding to stand conditions in which competition is added as influential shaping factor, aside genetic program of the species, is described for each stem diameter class. Crown regions with highest shape variability, from the perspective of stage developmentof the trees, were determined. Accordingly, the main crown shape characteristics are: crown elongation, mass center, asymmetry with regard to the main axis, lateral regions symmetrical and asymmetrical variations

Eyewitnesses’ Visual Recollection in Suspect Identification by using Facial Appearance Model

يعتبر تمييز الوجه مجالًا نشطًا لعلوم التصوير. ومع التطورات الحديثة في تطوير رؤية الكمبيوتر ، يتم تطبيقه على نطاق واسع في مختلف المجالات ، وخاصة في فرض القانون والأمن. ان الوجه البشري مقياس حيوي يمكن استخدامه بفعالية في كل من تحديد الهوية والتحقق منها. حتى الآن ، وبغض النظر عن نموذج الوجه والمقاييس ذات الصلة المستخدمة ، فإن عيبه الرئيس هو أنه يتطلب صورة للوجه ، يتم إجراء المقارنة عليها. لذلك ، هناك حاجة دائمًا إلى أجهزة تلفزيون الدائرة المغلقة وقاعدة بيانات الوجه في نظام التشغيل. وللأسف خلال العقود القليلة الماضية ، شهدنا ظهور حرب غير متكافئة ، حيث يتم ارتكاب أعمال إرهابية في كثير من الأحيان في منطقة منعزلة بدون كاميرا مثبتة وربما بواسطة أشخاص لم يتم حفظ صورهم في أي قاعدة بيانات رسمية قبل الحدث. خلال التحقيقات اللاحقة ، كان على السلطات بالتالي الاعتماد على شهود مصابين بصدمات نفسية واحباط ، وهؤلاء تعتبر شهادتهم مشكوك فيها وغالبًا ما تكون مضللة بشأن ظهور المشتبه فيه. لمعالجة هذه المشكلة ، تقدم هذه الورقة تطبيقًا لنموذج المظهر الإحصائي للوجه الإنساني في المساعدة على تحديد هوية المشتبه به استنادًا إلى التذكر البصري للشاهد. تم تنفيذ نظام نموذج أولي عبر الإنترنت لإظهار وظائفه الأساسية. أشار كل من التقييمات المرئية والعددية الواردة هنا بشكل واضح إلى الفوائد المحتملة للنظام للغرض المقصود.Facial recognition has been an active field of imaging science. With the recent progresses in computer vision development, it is extensively applied in various areas, especially in law enforcement and security. Human face is a viable biometric that could be effectively used in both identification and verification. Thus far, regardless of a facial model and relevant metrics employed, its main shortcoming is that it requires a facial image, against which comparison is made. Therefore, closed circuit televisions and a facial database are always needed in an operational system. For the last few decades, unfortunately, we have experienced an emergence of asymmetric warfare, where acts of terrorism are often committed in secluded area with no camera installed and possibly by persons whose photos have never been kept in any official database prior to the event. During subsequent investigations, the authorities thus had to rely on traumatized and frustrated witnesses, whose testimonial accounts regarding suspect’s appearance are dubious and often misleading. To address this issue, this paper presents an application of a statistical appearance model of human face in assisting suspect identification based on witness’s visual recollection. An online prototype system was implemented to demonstrate its core functionalities. Both visual and numerical assessments reported herein evidentially indicated potential benefits of the system for the intended purpose

Changes in Dynamics upon Oligomerization Regulate Substrate Binding and Allostery in Amino Acid Kinase Family Members

Oligomerization is a functional requirement for many proteins. The interfacial interactions and the overall packing geometry of the individual monomers are viewed as important determinants of the thermodynamic stability and allosteric regulation of oligomers. The present study focuses on the role of the interfacial interactions and overall contact topology in the dynamic features acquired in the oligomeric state. To this aim, the collective dynamics of enzymes belonging to the amino acid kinase family both in dimeric and hexameric forms are examined by means of an elastic network model, and the softest collective motions (i.e., lowest frequency or global modes of motions) favored by the overall architecture are analyzed. Notably, the lowest-frequency modes accessible to the individual subunits in the absence of multimerization are conserved to a large extent in the oligomer, suggesting that the oligomer takes advantage of the intrinsic dynamics of the individual monomers. At the same time, oligomerization stiffens the interfacial regions of the monomers and confers new cooperative modes that exploit the rigid-body translational and rotational degrees of freedom of the intact monomers. The present study sheds light on the mechanism of cooperative inhibition of hexameric N-acetyl-L-glutamate kinase by arginine and on the allosteric regulation of UMP kinases. It also highlights the significance of the particular quaternary design in selectively determining the oligomer dynamics congruent with required ligand-binding and allosteric activities

Methodologies for non-linear dynamic simulations in product development

In this thesis the efficient numerical simulation of non-linear dynamic systems is addressed through the use of reduced models. The problem of reducing simulation time with marginal loss of accuracy has been studied for many decades, with the purpose of accelerating the design phase and allowing the use of more accurate virtual prototypes. The process of transforming an original model and describing a complex physical system into a less computational demanding one, is generically defined as model order reduction or model reduction. The resulting model is therefore known as reduced model. Despite decades of attempts and several successfully applied methods, this topic still represents an open point, especially for what concerns complex non-linear systems. The aim of this thesis is to develop methodologies which exploit the linear modal analysis as a reliable and consolidated tool in reducing the computational cost of non-linear systems. Formulations which retains the non-linear behaviour while exploiting well established linear analyses are sought. Non-linearities in non-linear systems can then be retained or linearised around linearisation points. After a review of the literature, in Chapter 2, both approaches are examined. First, a reduced model which dedefines the non-linearities in a cubic form is implemented (Chapter 3). Then, a novel reduction method based on the linearisation in the configurations space is proposed in Chapter 4 and 5. Chapter 4 discusses the linearisation procedure, with the use of a specific base for each linearisation point, so that the non-linear system is globally approximated by a piecewise linear system, described through a set of linear ones. Interactions between them are then used to retain the non-linear properties, with the local linearised systems named subsystems. The reduction of the model is discussed in Chapter 5, with a focus on the mode selection procedure in generating reduced linear subsystems, while in Chapter 6, after an application to a simple lumped system, two categories of examples are proposed, defining two possible interaction methods regarding the set of subsystems. In the first category a discrete interaction is used, with a subsystem replacing the previous one, while in the second category a continuous interaction is implemented, with more reduced linear subsystems evolving simultaneously. For each category single and multi-parameters examples are proposed, with an analysis of the performance included. The method discussed in Chapter 3 is implemented, developing a non-linear beam element and testing the reduction on both numerical and experimental cases. Good agreement in reproducing the reference data is proven for the considered examples. The novel method developed in Chapter 4 and 5 is described, discussed and applied to several numerical examples. This method proves effective in reducing the computational time while maintaining a good approximation. An energy-based mode selection algorithm is introduced and applied, showing positive effects on the model reduction method performance

Reduced order models for thermally coupled low Mach flows

In this paper we present a collection of techniques used to formulate a projection-based reduced order model (ROM) for zero Mach limit thermally coupled Navier–Stokes equations. The formulation derives from a standard proper orthogonal decomposition (POD) model reduction, and includes modifications to improve the drawbacks caused by the inherent non-linearity of the used Navier–Stokes equations: a hyper-ROM technique based on mesh coarsening; an implicit ROM subscales formulation based on a variational multi-scale (VMS) framework; and a Petrov–Galerkin projection necessary in the case of non-symmetric terms. At the end of the article, we test the proposed ROM formulation using 2D and 3D versions of the same example: a differentially heated cavity.Peer ReviewedPostprint (published version

Basic comparison of particle size distribution measurements of pigments and fillers using commonly available industrial methods

The Nanobiosciences Unit of the Joint Research Centre’s Institute for Health and Consumer Protection and Eurocolour, the association of European pigments, dyes and fillers industry, have carried out a program of work to evaluate a number of instrumental methods of measuring particle size distributions as required for assessing compliance versus the EU Recommendation for the definition on nanomaterials. The study has examined the use of five instrumental methods applied to a range of eight widely different but industrially relevant powder pigments. The techniques examined were Laser Diffraction (LD), Dynamic Light Scattering (DLS), Centrifugal Liquid Sedimentation (CLS), Volume Specific Surface Area (VSSA) and Electron Microscopy (EM). This report describes the materials studied and the preparative and analytical methods used. Individual chapters provide an overview of the single analytical methods used together with a summary of the results obtained using each particular method. In considering the results of this study it is important to note that the aim was not to determine the optimum conditions for every individual sample but rather to produce and evaluate data which could be considered representative of that obtainable in industrial laboratories using existing instrumental facilities operated by experienced but not specialised operators. The report discusses the challenges of using these instrumental methods to obtain a simple unambiguous classification of the test materials according to the EC definition.JRC.I.4-Nanobioscience

Correcting direction-dependent gains in the deconvolution of radio interferometric images

Astronomical imaging using aperture synthesis telescopes requires deconvolution of the point spread function as well as calibration of instrumental and atmospheric effects. In general, such effects are time-variable and vary across the field of view as well, resulting in direction-dependent (DD), time-varying gains. Most existing imaging and calibration algorithms assume that the corruptions are direction independent, preventing even moderate dynamic range full-beam, full-Stokes imaging. We present a general framework for imaging algorithms which incorporate DD errors. We describe as well an iterative deconvolution algorithm that corrects known DD errors due to the antenna power patterns and pointing errors for high dynamic range full-beam polarimetric imaging. Using simulations we demonstrate that errors due to realistic primary beams as well as antenna pointing errors will limit the dynamic range of upcoming higher sensitivity instruments and that our new algorithm can be used to correct for such errors. We have applied this algorithm to VLA 1.4 GHz observations of a field that contains two ``4C'' sources and have obtained Stokes-I and -V images with systematic errors that are one order of magnitude lower than those obtained with conventional imaging tools. Our simulations show that on data with no other calibration errors, the algorithm corrects pointing errors as well as errors due to known asymmetries in the antenna pattern.Comment: submitted to A&A; some clarifications added in the text; accepted for publication in A&

Molecular Imaging of Prostate Cancer

Chapter 1 addresses the introduction to the thesis and provides epidemiology, etiology, metastatic spread, current diagnostics and clinical need of new biomarker for risk stratification of prostate cancer. Chapter 2 provides a detailed analysis of the distribution pattern of the three most used choline tracers: 18F-methylcholine, 11C-choline, and 18F-ethylcholine in metabolically and anatomically disease-free patients. The ranges of SUVmax, SUVmean and standard deviations have been presented. Potential pitfalls in evaluation of “non-avid” but clinically significant presentation of different disease entities are also addressed. The chapter provides overview of the variations in choline uptake pattern which is vital for assessment of various organs when imaging is performed for evaluation of metastatic disease. Chapter 3 presents the feasibility of assessing dynamic 18F Ethyl Choline PET with a view to do kinetic modelling in clinical setting of biochemical relapse of Prostate Cancer. This critical piece of work underpins the quantification, tracer kinetics and demonstrates that cancerous tissue shows abnormal perfusion. From these observations I was able to conclude that 18F Choline can act as a biomarker to assess angiogenesis in prostate cancer and introduces 18F Choline as a biomarker for further work presented in chapter 4-8. Chapter 4 addresses the detection of clinically significant and insignificant prostate cancer on 18F-FECH PET/CT and I correlated findings with template guided prostate mapping biopsy (TPM). Sensitivity and Specificity data of 8F-FECH PET/CT has been provided. Chapter 5 addresses the accuracy of 18F Choline PET/MR which is compared to reference standard (template guided prostate mapping biopsy). This work suggests that data obtained from 18F Choline PET/MR can allow detection of clinically significant and insignificant prostate cancer. I noted that multiple previous treatments can give false positive results and 18F Choline PET/MR is the imaging investigation of choice post HIFU. Moreover, false negative results with 18F Choline PET/MR can be due to very small volume (=/<2 mm) disease. Chapter 6 presents the differential diagnosis of abnormal tracer accumulation in the Prostate and periprostatic tissue. Chapter 7 provides spectrum of skeletal findings on dual-phase 18F-fluoroethylcholine (FECH) PET/CT performed during the work-up of patients referred for suspected prostate cancer relapse. I have provided quantification data and explained that SUVmax in isolation cannot be used to characterize these lesions as benign or malignant. Minimal overlap of benign and malignant lesions also exists. Chapter 8 addresses the clinical utility of 18F Choline in the setting of clinical trial in collaboration with Uro-oncology, Nuclear Medicine and Radiology departments. This critical work compares 18F Choline PET-CT and Whole-Body MRI in assessment and decision-making process for salvage treatment of focal radio-recurrent prostate cancer. This chapters concludes that at present WB-MRI cannot be used alone as imaging modality for investigation of biochemical relapse of Prostate Cancer. Chapter 9 is a summary of main findings and discussions from chapters in this thesis. It also highlights the potential applications and future perspectives of novel biomarkers for imaging of prostate cancer