Structural properties of silicon dioxide thin films densified by medium-energy particles

Classical molecular-dynamics simulations have been carried out to investigate densification mechanisms in silicon dioxide thin films deposited on an amorphous silica surface, according to a simplified ion-beam assisted deposition (IBAD) scenario. We compare the structures resulting from the deposition of near-thermal (1 eV) SiO$_{2}$ particles to those obtained with increasing fraction of 30 eV SiO$_{2}$ particles. Our results show that there is an energy interval - between 12 and 15 eV per condensing SiO$_2$ unit on average - for which the growth leads to a dense, low-stress amorphous structure, in satisfactory agreement with the results of low-energy ion-beam experiments. We also find that the crossover between low- and high-density films is associated with a tensile to compressive stress transition, and a simultaneous healing of structural defects of the {\em a-}SiO$_2$ network, namely three- and four-fold rings. It is observed, finally, that densification proceeds through significant changes at intermediate length scales (4--10 \AA), leaving essentially unchanged the ``building blocks'' of the network, viz. the Si(O$_{1/2}$)$_{4}$ tetrahedra. This latter result is in qualitative agreement with the mechanism proposed to explain the irreversible densification of amorphous silica recovered from high pressures ($\sim$ 15--20 GPa).Comment: 12 pages including 10 postscript figures; submitted to Phys. Rev. B; related publications can be found on web site http://www.centrcn.umontreal.ca/~lewi

Effect of levodopa on cortico-striatal and cortico-cerebellar circuits in Parkinson's disease

La maladie de Parkinson (MP) est la deuxième maladie neurodégénérative la plus commune. Les symptômes principalement observés chez les patients atteints de la MP sont la rigidité, les tremblements, la bradykinésie et une instabilité posturale. Leur sévérité est souvent asymétrique. La cause principale de ces symptômes moteurs est la dégénérescence du circuit dopaminergique nigro-striatal qui mène à un débalancement d’activité du circuit cortico-striatal. Ce débalancement de circuits est le point essentiel de cette thèse. Dans les protocoles de recherche décrits ici, des patients atteints de la MP (avant et après une dose de levodopa) et des participants contrôles sains ont effectué des mouvements auto-initiés ou en réponse à des stimulis externes pendant que l’on mesurait leur activité cérébrale en imagerie par résonance magnétique fonctionnelle (IRMf). Dans cette thèse, nous abordons et mettons en évidence quatre (4) points principaux. En première partie (chapitre 2), nous présentons un recensement de la littérature sur les cicruits cortico-striataux et cortico-cérébelleux dans la MP. En utilisant des méthodes de neuroimagerie, des changements d’activité cérébrale et cérébelleuse ont été observés chez les patients atteints de la MP comparés aux participants sains. Même si les augmentations d’activité du cervelet ont souvent été attribuées à des mécanismes compensatoires, nos résultats suggèrent qu’elles sont plus probablement liées aux changements pathophysiologiques de la MP et à la perturbation du circuit cortico-cérébelleux. En général, nous suggérons (1) que le circuit cortico-cérébelleux est perturbé chez les patients atteints de la MP, et que les changements d’activité du cervelet sont liés à la pathophysiologie de la MP plutôt qu’à des mécanismes compensatoires. En deuxième partie (chapitre 3), nous discutons des effets de la levodopa sur les hausses et baisses d’activité observés chez les patients atteints de la MP, ainsi que sur l’activité du putamen pendant les mouvements d’origine interne et externe. De nombreuses études en neuroimagerie ont montré une baisse d’activité (hypo-activité) préfrontale liée à la déplétion de dopamine. En revanche, l’utilisation de tâches cognitives a montré des augmentations d’activité (hyper-activité) corticale chez les patients atteints de la MP comparés aux participants sains. Nous avons suggéré précédemment que ces hypo- et hyper-activités des régions préfrontales dépendent de l’implication du striatum. Dans cette thèse nous suggérons de plus (2) que la levodopa ne rétablit pas ces hyper-activations, mais plutôt qu’elles sont liées à la perturbation du circuit méso-cortical, et aussi possiblement associées à l’administration de médication dopaminergique à long terme. Nous montrons aussi (3) que la levodopa a un effet non-spécifique à la tâche sur l’activité du circuit cortico-striatal moteur, et qu’elle n’a pas d’effet sur l’activité du circuit cortico-striatal cognitif. Nous montrons enfin (chapitre 4) que la levodopa a un effet asymétrique sur les mouvements de la main droite et gauche. À peu près 50% des patients atteints de la MP démontrent une asymétrie des symptômes moteurs, et ceci persiste à travers la durée de la maladie. Nos résultats suggèrent (4) que la levodopa pourrait avoir un plus grand effet sur les patrons d’activations des mouvements de la main la plus affectée.Parkinson’s disease (PD) is the second most common neurodegenerative disease, mainly manifested by tremor, rigidity, bradykinesia and postural instability, and often an asymmetry of symptom severity of the left and right sides of the body. The depletion of dopamine of the nigrostriatal pathway is the primary cause of the motor symptoms observed in patients with PD, leading to an imbalance in basal-ganglia prefrontal circuits. In the protocols described here, patients with PD before and after levodopa administration and healthy participants performed self-initiated (SI) and externally triggered (ET) movements with the left and right hand during functional magnetic resonance imaging (fMRI). In the chapters of this thesis, we argue and provide evidence for four main points. The first portion (chapter 2) provides a literature review on cortico-striatal and cortico-cerebellar circuit disruption in PD. Using neuroimaging techniques, changes in cerebral and cerebellar activity have been observed in patients with PD compared with healthy participants. Although increases in activity in the cerebellum have often been interpreted as compensatory mechanisms, we provide evidence that they are more likely to be related to pathophysiological changes of the disease, and the disruption of the cortico- cerebellar circuit. In general, we argue (1) is that activity in the cerebellum is linked to the pathophysiology of PD. In the second section (chapter 3) we discuss the effect of levodopa on the patterns of cortical hypo- and hyper-activity in PD, as well as the activity of the putamen in SI and ET movements. Many studies have shown cortical hypo-activity in relation to nigrostriatal dopamine depletion. In contrast, some cognitive studies have also identified increases in cortical activity in patients with PD as compared with healthy control participants. We have previously suggested that cortical hypo- and hyper-activations depend on striatal recruitment. In this thesis, we further show that hyper-activations in the prefrontal cortex are not reestablished with levodopa administration. We suggest (2) that they are rather associated with mesocortical dopamine circuit dysfunction, and perhaps linked with long- term dopaminergic medication administration. Furthermore, we show (3) that levodopa has a non-task specific effect on the motor cortico-striatal loop, but does not affect the cognitive cortico-striatal circuit. Finally (chapter 4), we show that the effect of levodopa on movements of the left and right hands is not symmetrical. Previous studies have shown that in about 50% of patients, one side of the body is more severely affected, and this asymmetry persists throughout the duration of the disease. Our results suggest (4) that levodopa may have stronger effects on the cerebral hemodynamic patterns related to the movements of the more affected hand than on those of the less affected hand

Kedudukan Ahli Waris dalam Waris Adat Nias (Penelitian pada Masyarakat Nias di Kecamatan Boronadu Kabupaten Nias Selatan)

Indonesia adalah Negara hukum yang dikenal dengan ragam agama, suku dan ras yang kaya dengan aturan-aturan hukumnya. Hukum adat telah diakui di Indonesia dengan jaminan tidak melanggar dan tidak menghilangkan nilai-nilai pancasila dan prinsip-prinsip Negara Republik Indonesia. Masyarakat Nias memiliki aturan warisan sendiri yang berdasar kepercayan agama yang dianggap tidak bertentangan dengan prinsip-prinsip Negara Kesatuan Republik Indonesia. Permasalahan yang akan diteliti dalam kedudukan ahli waris dalam waris adat Nias yang penelitiannya pada masyarakat Nias di Kecamatan Boronadu Kabupaten Nias Selatan adalah : 1). Bagaimana keduduakan ahli waris dalam waris adat nias. 2). Bagaimana sistem pewarisan dalam waris adat nias. 3). Apa yang yang menjadi Faktor-faktor penghalang (tidak pantas) menjadi ahli waris. Hukum adat “adat recht” adalah seluruh peraturan, yang ditetapkan dalam keputusan-keputusan yang penuh wibawa, dan yang dalam pelaksanaanya diterapkan “begitu saja” artinya tanpa adanya keseluruhan peraturan, yang dalam kelahirannya dinyatakan mengikat sama sekali. Hukum waris adalah hukum yang mengatur tentang peralihan harta kekayaan yang di tinggalkan seseorang yang meninggal serta akibatnya bagi para ahli waris. Dalam hal ini objek dari peralihan itu ialah harta yang di tinggalkan si peniggal. Jenis penelitian dalam penelitian ini mengunakan metode jenis Penelitian Yuridis Normatif yaitu dimana penulis akan mencari fakta-fakta yang akurat dengan mempelajari norma-norma yang ada yang selalu diindahkan oleh masyarakat yang menggunakan sumber data primer dan sekunder. Sifat penelitian yang dipergunakan dalam menyelesaiakan skripsi ini adalah deskriptif analisis dari beberapa peraturan adat istiadat yang ada di daerah Nias mengenai Hukum Waris Adat Suku Nias yang khusus penelitiannya di Kecamatan Boronadu Kabupaten Nias Selatan. Teknik pengumpulan data yaitu penelitian Keperpustakaan (Liberary Research) yaitu dengan melakukan penelitian terhadap berbagai sumber bacaan yaitu buku, majalah hukum, pendapat para sarjana, peraturan undang-undang dan juga bahan-bahan kuliah. Peneltian Lapangan (field Research) yaitu dengan melakukan kelapangan dalam hali ini langsung melakukan studi di Kecamatan Boronadu Kabupaten Nias Selatan dengan wawancara terhadap Kepala adat dan Petingi-petingi adat. Boronadu adalah salah satu kecamatan dari beberapa kecamatan di Kabupaten Nias Selatan yang terletak di daerah Selatan yang menduduki ± 10.000 jiwa, Desa yang dituju untuk tempat penelitian tepat pada desa Bohalu yang dihuni oleh 80 rumah dan 90 kk (Kepala Keluarga). Disana masyarakat adatnya mayoritas bertani dan bercocok tanam dalam mencukupi dan menafkahi hidup. Kedudukan ahli waris/anak menurut hukum adat sebagai ahli waris atau anak kandung memiliki kedudukan yang terpenting dalam tiap masyarakat adat yang berlaku di kecamatan Boronadu Kabupaten Nias Selatan. Sistem pewarisan adat Nias yaitu sistem Kebapakan (patriarchaat, vaderrechclijk) Yaitu masyarakat yang mengacu atau bertumpu kepada hubungan darah melalui garis keturunan laki-laki, sehingga yang berhak meneruskan garis keturunan hanyalah anak laki-laki. Faktor yang menjadi penghalang ahli waris. Orang yang telah dijatuhi hukuman karena membunuh atau mencoba membunuh orang yang meninggal itu, orang yang dengan putusan hakim Pernah dipersalahkan karena dengan fitnah telah mengajukan tuduhan terhadap pewaris, bahwa pewaris pernah melakukan suatu kejahatan yang diancam dengan hukuman penjara lima tahun atau hukuman yang lebih berat lagi, Orang yang telah menghalangi orang yang telah meninggal itu dengan kekerasan atau perbuatan nyata untuk membuat atau menarik kembali wasiatnya, orang yang telah menggelapakan. Memusnahkan atau memalsukan wasiat orang meninggal itu.Indonesia is a country of law known for its diversity of religions, tribes and races rich in its legal rules. Customary law has been recognized in Indonesia with the guarantee of non-infringement and does not remove the values of Pancasila and the principles of the Republic of Indonesia. The people of Nias have their own inheritance rules based on religious beliefs that are considered not against the principles of the Unitary State of the Republic of Indonesia. The problems to be studied in the position of heirs in indigenous inheritance of Nias whose research on Nias community in Boronadu District of South Nias Regency are: 1). How is the heir of the heirs in Nias customary heritage. 2). How is the inheritance system in the customary inheritance of nias. 3). What are the Barrier Factors (inappropriate) become the heirs. The customary law of "custom recht " is the whole ordinance, stipulated in authoritative decisions, and which in its implementation is applied "offhand" meaning without the existence of the whole rule, which in its birth is declared binding at all. The law of inheritance is the law which regulates the transfer of wealth which is left behind by a deceased person and the consequences for the heirs. In this case the object of the transition is the property left by the penitent. The type of research in this study using the method of type Normative Juridical Research is where the authors will look for accurate facts by studying existing norms that are always ignored by people who use primary and secondary data sources. The nature of the research used in completing this thesis is the descriptive analysis of some customary rules that exist in the Nias area on the customary law of customary law of Nias tribe who specialized in Boronadu District of South Nias Regency. Technique of collecting data is library research (Library Research) that is by doing research to various source of reading that is book, law magazine, opinion of scholars, law regulation and also lecture materials. Field Research (Field Research) is by doing spaciousness in this directly conduct studies in Boronadu District of South Nias Regency with interviews with customary head and indigenous petingi. Boronadu is one of the sub districts of several sub-districts in South Nias District located in the South that occupies about 10,000 people, The designated village for the study site is Bohalu village which is inhabited by 80 houses and 90 families (Head of Family)

The origin of the E+ transition in GaAsN alloys

Optical properties of GaAsN system with nitrogen concentrations in the range of 0.9-3.7% are studied by full-potential LAPW method in a supercell approach. The E+ transition is identified by calculating the imaginary part of the dielectric function. The evolution of the energy of this transition with nitrogen concentration is studied and the origin of this transition is identified by analyzing the contributions to the dielectric function from different band combinations. The L_1c-derived states are shown to play an important role in the formation of the E+ transition, which was also suggested by recent experiments. At the same time the nitrogen-induced modification of the first conduction band of the host compound are also found to contribute significantly to the E+ transition. Further, the study of several model supercells demonstrated the significant influence of the nitrogen potential on the optical properties of the GaAsN system.Comment: 5 pages, 3 figure

Surface engineering and vapor phase technologies for coating and functionalizing complex objects and small particles

The requirements for materials performance in different areas of application continues to face increased technological, economical and environmental challenges, while considering ever improving materials mechanical, optical, electrical, electrochemical and other functional properties and their combination (multifuntionality). This opens new and exciting opportunities for further development of surface engineering methodologies that allow one to fabricate functional coatings and functionalized surfaces with tailored characteristics. Further progress in this field is only possible when considering a holistic approach in which the desired functions are well understood and closely linked with the materials microstructure and the detailed physical and chemical reactions involved in the processes. This presentation will describe the progress in surface engineering of materials using chemical vapor deposition, physical vapor deposition, and plasma-enhanced chemical vapor deposition of functional coatings. It will particularly focus on the following aspects: a) Effect of surface reactions on the evolution of the coating microstructure during the film growth in different pressure regimes ranging from vacuum to the atmospheric pressure. b) Relationship between the microstructure and the film functional characteristics suitable for different areas of application including optics, aerospace, energy, manufacturing and others. c) Application of the vapor phase deposition techniques to coat complex objects including small particles. The latter one will be illustrated by our recent results on the development of the fluidized bed chemical vapor deposition process. Throughout the presentation, we demonstrate the need for advanced diagnostic techniques suitable for the process and materials control on the nanoscale

Longitudinal dose and type of immunosuppression in a national cohort of Australian liver, heart, and lung transplant recipients, 1984-2006

Unconfounded comparative data on the type and dose of immunosuppressive agents among solid organ transplant recipients are sparse, as are data on longitudinal immunosuppressive therapy since transplantation. We addressed this issue in a population-based cohort of Australian liver (n = 1895), heart (n = 1220), and lung (n = 1059) transplant recipients, 1984-2006. Data on immunosuppressive therapy were retrospectively collected at discharge, three months, and one, five, 10, and 15 yr after first transplant. We computed unadjusted and adjusted estimates for the association between the type and dose of immunosuppressive therapy and organ type. After adjustment for confounders, use of induction antibody and maintenance corticosteroids was more common in heart and lung compared to liver recipients (p < 0.001), and antibody therapy for rejection more common in liver recipients (p < 0.001). Liver recipients were more likely to receive calcineurin inhibitor monotherapy, with or without corticosteroids, compared to heart and lung recipients (p < 0.001). Liver recipients consistently received lower doses of azathioprine than heart and lung recipients (p < 0.001). These differences in immunosuppression may partly explain variations in immunosuppression-related morbidity by transplanted organ, for example, malignancy risk. Longitudinal changes in the type and the dose of immunosuppressive therapy over time since transplantation also demonstrate the need for time-dependent data in observational research

Conformal multilayer coatings on fine silica microspheres by atmospheric pressure fluidized bed chemical vapor deposition

Surface properties of fine particles can be tuned through deposition of films or coatings. This approach is an area of science and technology of interest in numerous fields such as catalysis, energy production, microelectronics, optoelectronics, etc. Surface coating of powders can be applied by a dry technique (i.e., the use of a reactive gas phase), so-called chemical vapor deposition (CVD). However, conventional CVD processes cannot provide an efficient conformal deposition while fine particles are considered as substrates. This is due to the fact that mixing of particles, in such a way that their entire surface is exposed to the reactive gas phase, is rather complicated and not often addressed. Therefore, fluidization, as a recognized particle treatment process which meets the requirement of gas–solid contact, can be associated with the gas–solid reactions that are often used in the context of various CVD processes. The combination of such mature techniques, namely fluidized bed chemical vapor deposition (FBCVD) leads to innovative, flexible and cost-effective particle treatment processes [1]. In the present investigation, soda lime spherical particles with a particle size of ca. 27 µm were used as the substrate. Single- and multi-layer depositions composed of TiO2 and SiO2 films were applied to the surface of the particles by the FBCVD at atmospheric pressure, while employing, respectively, titanium and silicon tetrachloride as precursors, and using water as an oxidation agent. TiO2 and SiO2 films were deposited at 300oC and ambient temperatures, respectively. Please click Additional Files below to see the full abstract

The Broker Simulation Model in the Emission Allowances Trading Area

This paper is focused on possibilities of simulations of emission allowances trading within the EU emission trading system using new designed broker simulation model which integrates different original soft computing and decision making methods. Firstly, the paper presents the background of the EU emissions trading system and an overview of different methods used in current research connected with CO2 emission allowances trading. The key part of the paper focuses on the broker simulation model creation and application. The results are based on expert systems with fuzzy rule bases, nonlinear fuzzy rule based predictors and fuzzy rule based behavior modelling. The application part of the results has been performed in Matlab. The broker simulation model is able to make decisions connected with the traded amount, price of allowances and buy/sell actions within the time on the market. Keywords: EU ETS; Fuzzy modelling; Broker JEL Classifications: C44; Q48; Q5

Zirconia-titania-doped tantala optical coatings for low mechanical loss Bragg mirrors

The noise caused by internal mechanical dissipation in the high refractive index amorphous thin films in dielectric mirrors is an important limitation for gravitational wave detection. The objective of this study is to decrease this noise spectral density, which is linearly dependent on such dissipation and characterized by the loss angle of the Young’s modulus, by adding zirconia to titania-doped tantala, from which the current mirrors for gravitational wave detection are made. The purpose of adding zirconia is to raise the crystallization temperature, which allows the material to be more relaxed by raising the practical annealing temperature. The Ta, Ti and Zr oxides are deposited by reactive magnetron sputtering in an Ar:O2 atmosphere using radio-frequency and high power impulse plasma excitation. We show that thanks to zirconia, the crystallization temperature rises by more than 150◦C, which allows one to obtain a loss angle of 2.5 × 10−4 , that is, a decrease by a factor of 1.5 compared to the current mirror high-index layers. However, due to a difference in the coefficient of thermal expansion between the thin film and the silica substrate, cracks appear at high annealing temperature. In response, a silica capping layer is applied to increase the temperature of crack formation by 100◦C