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Posuzování synergických efektů u vybraného konsolidovaného subjektu / Assessing the Synergistic Effects of the Selected Consolidated EntityNováčková, Veronika January 2016 (has links)
The thesis focuses on the methods of assessment of synergy effects in a consolidated entity. The text includes a assessment of economic situation of the consolidated unit and analyzes a draft set of economic indicators suitable for assessing of synergy effect. Synergy effect is monitored in several selected areas through a comparison between the consolidated unit and the mother company. Results of the analysis of the draft indicators are assessed to determine whether synergies were achieved after the acquisition.
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Characteristics associated with unplanned extubation in an intensive care unit Nairobi, KenyaAhamed, Parin Hanif 11 1900 (has links)
Unplanned extubation is premature removal of endotracheal tube, is an adverse event; which can either, be accidental during a nursing procedure or self deliberate by the patient. The AACN Synergy Model for Patient Care was used as conceptual model for this study. A retrospective descriptive design revealed that over a period of two years, 327 patients admitted to the intensive care unit require intubation of which 40.4% were self-deliberate extubation and 59.4% accidental extubation. Of the accidental extubated patients, 29.8% had physical restrains, 57.6% received sedation, 43.9% had analgesic infusion and 38.9% were on neuromuscular blockade. A means Glasco Coma Scale was 9.4 and 56% of the patients were reported as being. Most patients (89.9%) required re-intubation. The findings also revealed that 49.1% of the nurses who cared for the patients when the extubation occured had one patient at the time. Also, 84.2% of nurses had 0-6 years of nursing experience and 74% of nurses had less than five years of ICU experience. / Health Studies / M.A. (Health Studies)
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A collaborative approach towards enhancing synergy in a critical care unit in GautengDe Kock, Juliana 22 April 2014 (has links)
In today’s world healthcare all over the world is profoundly challenged by rapid
technological advancements, violence, terrorism, diverse cultures, proliferating chronic
diseases, and the worst nursing shortage. In addition to these complex and daunting
challenges healthcare continue to focus the attention on hospitals to review and modify
the way care is delivered to patients. As key role players and consistent members of the
multidisciplinary team critical care nurses are uniquely positioned to modify and review
the quality of patient care through synergy between the patients’ needs, the nurses’
competencies, and the critical care environment.
A collaborative approach towards enhancing synergy in a CCU was undertaken in a
CCU in a private hospital in Gauteng. The study was guided by the American
Association for Critical Care Nurses Synergy Model for Patient Care and conducted
within the critical social theory paradigm. The nature of the research was descriptive,
explorative and contextual and both qualitative and quantitative approaches were used.
Action research cycles were followed to assess existing synergy between the patients’
needs, the nurses’ competencies and the characteristics of the environment in the CCU.
An action plan was formulated and implemented towards enhancing synergy in the
CCU. The implemented plan was adjusted based on observations and reflections
following each of the five cycles of the project / Health Studies / D. Litt. et Phil. (Health Studies)
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The didactics of an English-Bemba anthology of oral traditional narratives in the Zambian Grade Ten literature classMwelwa, Joseph Mulenga 06 1900 (has links)
Within the multilingual context of Zambia, Grade Ten Literature in English language pedagogy could incorporate the learners’ language and culture to help enrich participation and facilitate understanding of concepts among the learners who are in the foundational year of the literature course. However, current Literature in English language pedagogy is characterized by a monolingual practice with English dominating the literature learning/teaching classroom space – thus rendering the learners’ local linguistic and cultural knowledge impotent. To remedy the situation, the study investigated a dominant local language – Bemba – for a linguistic genre suitable for use in Literature in English language pedagogy. Archival retrieval and live recording of Bemba oral traditional narratives produced the initial research data. Transcription and translation techniques created an anthology from which a bilingual resource (BR) was derived. The BR was then trialled among Grade Ten Literature in English language learners in schools in the Copperbelt province of Zambia. Focus group discussions by participants generated evaluative data whose analysis using qualitative techniques indicate that learners responded positively to the bilingual materials and approach. Teachers were equally enthusiastic, describing the bilingual approach to Literature in English language pedagogy as unique, innovative and liberating. A Linguistic Synergy theory was thus developed to account for teachers’ and learners’ experiences in a bilingual Literature in English classroom. / English Studies / D. Litt. et Phil. (English)
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從優勢競爭替代之觀點探討垂直市場競爭者之戰略型投資韓行一, Han,Henry Unknown Date (has links)
企業的持續成長是每一家企業所追求的目標之一,也是衡量企業營運績效之重要指標,當一個企業成長趨緩或開始衰退時,往往是企業遭遇困難的警訊。而企業能持續成長端賴競爭力之保有及持續提升,這在企業就必須具有企業競爭優勢策略,因而企業競爭優勢策略是提升企業經營績效的重要課題。
營運成長模式一般可分為內部成長與外部成長。內部成長是指經由公司內部新事業、新產品或新訂單與新客戶的增加使營業額成長;外部成長則是藉由外部策略聯盟、轉投資、購併等手段使公司能取得有利競爭優勢與地位或擴大營業規模。又因為藉由轉投資與購併經常能使企業之規模與競爭力獲得跳躍式成長,如美國通用電氣(General Electric)與思科(Cisco corp.)均為明顯而成功的案例,故在大部分企業經營時,其成為很多企業成長策略的主要選項。
然而,企業在選擇轉投資、策略聯盟或購併行為時,其策略與目標的訂定、購併與被購併企業之定位、整合;購併或轉投資的標的選擇與評估、計畫的規劃與執行等等,均影響外部成長之成敗,導致企業競爭力是否持續增進。
本研究針對垂直市場的產業內聯盟與轉投資為限制範圍,以聚焦於”垂直市場”產業內之轉投資有別於跨產業之投資行為,以”優勢競爭替代”之觀點來探討企業策略定位,以”組織變革”觀點來觀察購併與被購併或投資者與被投資者之定位策略與執行策略,以”累積長期競爭優勢”為標準來衡量與檢驗聯盟或轉投資之效益。
本研究針對研華股份有限公司轉投資艾訊股份有限公司之策略聯盟個案,以探索性研究方法依理論比較實務,研究其在策略聯盟之過程,探討此個案之策略與執行過程,期望能對研華與艾訊公司之策略作一研究與檢討並提出後續改進之建議。
本研究之歸納發現為:
一、 垂直市場競爭者之水平式策略聯盟或購併,如僅由發揮最大生產效率之綜效來考量,不易累積長久之競爭優勢。
二、 在垂直市場產業中,卓越的聯盟或購併之策略運用,在清楚的分析所處市場特性與公司定位以持續維持競爭優勢是策略思考的核心。
三、 破壞性創新思維運用在市場競爭策略上,市場在位者可提升維持性創新競爭力並同時可建立低階策略聯盟以形成阻止其他低階攻擊者障礙,足以保護現有市場在位領先者免於被競爭者侵蝕競爭力。形成結構上的長期競爭優勢。
四、 購併策略之執行,是否應將被併購企業併入,端賴兩方公司之策略定位。依據定位來檢視雙方之資源、流程與價值三個構面,當此三構面在雙方整合對整體策略有助益,則雙方應合併,反之則應維持獨立運作。
五、 雖然處於相同產業,但競爭之主要成功因素將因企業為維持性創新之市場在位者,或是防止低階、低價進攻者之阻攻者角色而有所改變;相對應的組織變革就應提出以確保策略之成功執行。 / The continuous revenue growth is one of the utmost goals that every enterprise seeks. It is also one of the key factors to measure the operation efficiency of an enterprise. It is an alarming signal that the enterprise is encountering serious challenges whenever the sales growth stays slow or encounters a recession. In order to keep the revenue grow consistently, an enterprise needs to sustain its competitiveness and keep its ascendancy as its cutting edge strategy.
We can classify the growth engines into two categories: first, the internal growth engine which is contributed by new business, new products, and new orders; second, the external growth engine which is contributed by strategic alliances, M&A, and other investment opportunities. The enterprise usually gets a quantum jump on its business scale when a successful Merger & Acquisition is executed. The General Electric Co. and Cisco Co. cases are good examples of M&A. This probably explains why many companies place M&A and investment opportunity on high priority when setting growth strategies.
However, when an enterprise adopts strategic alliance, M&A or diversified investment, its success depends heavily on its abilities of goal setting, positioning, targeting of Alliance Company, doing due-diligence, and solving culture conflict.
This thesis investigates the strategic alliances and diversification investment between vertical market players, to focus on monistic industrial investment instead of cross industrial investment; reviews the company positioning strategy from the point of ascendancy competitiveness strategy; studies the execution of organization change between merger and merged companies and verifies the effectiveness of strategic alliances from the viewpoint of accumulated long term competitiveness advantages.
The thesis studies from theoretical research to the case study of Advantech Co. which applies the exploratory research method. The Advantech Co. conducted an alliance with Axiomtek Co. in 2002 by stock swap between the two companies. Advantech owns 65% of Axiomtek after the alliance. It is my purpose to assay the process of strategic alliance and try to provide some advices to improve the effectiveness of this strategy.
Conclusions can be summarized as follows
1. The strategic alliances or diversification investment between vertical market players can contribute less for cumulating the competitiveness if it is targeted to prevail by maximizing the production efficiency synergy.
2. A superior alliance strategy in vertical market is to analyze the market attributes and anchor the company positioning which helps the competitiveness accumulating for a player.
3. By implementing the disruptive innovation theory in market competition strategy, one company can develop alliance with a lower cost, 2nd tier or less functionality product provider to create the barrier for protecting attack from the disruptive competitors.
4. The resources, process and value are three scopes to judge whether two companies need be combined as one company or not. When those three measurements are formulating more advantages after combining based on mergers decision on companies positioning strategy, then, it should be combined as one company, otherwise vice versa.
5. The key success factors will be reformed accordingly if the acquirer re-positioning the company. A correspondent organization change also is recommended to be implemented.
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Rôles combinés des cytokines IL-2, IL-15 et IL-21 dans le développement et le maintien des lymphocytes T CD8+ mémoiresMathieu, Cédric 12 1900 (has links)
Suite à une infection, des lymphocytes T CD8+ naïfs (LTn CD8+) spécifiques d’un antigène du pathogène sont activés. Après, cette activation, ces lymphocytes se différencient en lymphocytes T effecteurs CD8+ (LTe CD8+) chargés d’éliminer le pathogène. Une fois que l’infection est résolue, la grande majorité des effecteurs meurent par apoptose et les survivants se différencient en lymphocytes T mémoires CD8+ (LTm CD8+). Ces derniers protègeront l’organisme à long terme contre une réinfection par le même pathogène. Il est ainsi primordial d’avoir une meilleure compréhension des mécanismes impliqués dans le développement et la maintenance des LTm CD8+.
Plusieurs études ont déjà montré que certaines cytokines de la famille γC (IL-2, IL-7, IL-15 et IL-21) influençaient individuellement le développement des LTe et LTm CD8+. Cependant, nous pensons que ces cytokines ont un impact bien plus grand sur l’homéostasie des LTe et LTm CD8+ que la littérature actuelle le laisse entendre. En effet, nous émettons l’hypothèse que ces cytokines de la famille γC agissent en synergie entre elles afin de promouvoir le développement des LTe et LTm CD8+. Pour tester notre hypothèse, nous avons dans un premier temps étudié l’impact combiné des signaux IL-2 et IL-15 sur la génération des LTe et LTm CD8+ dans un modèle d’infection LCMV Armstrong. Ensuite, dans le même modèle expérimental, nous avons étudié l’effet d’une déficience en signaux IL-2, IL-15 et IL-21 sur le développement des LTe et LTm CD8+. Nos résultats montrent que ces trois cytokines collaborent afin de soutenir l’expansion et la différenciation des LTe CD8+. Plus précisément, l’IL-2, l’IL-15 et l’IL-21 sont essentielles pour l’homéostasie d’une population particulière de LTe CD8+ : les Short-Lived Effector Cells (SLECs). Nous avons également mis en évidence que ces trois cytokines sont toutes les trois requises afin de générer un nombre maximum de LTm CD8+. De plus, la différenciation et le maintien de la population effecteur mémoire (TEM) sont particulièrement réduites en l’absence des signaux combinés de l’IL-2, l’IL-15 et l’IL-21.
Nos résultats mettent pour la première fois en lumière les rôles redondants et synergiques de trois cytokines dépendantes de la chaine γc dans le développement et la maintenance des LTe et LTm CD8+. / Over the course of an infection, antigenic signals trigger a specific CD8+ T cells (LTn
CD8+) response. Upon antigen recognition, LTn CD8+ are activated and undergo a massive
proliferation wave. This leads them to differentiate into effector cells (LTe CD8+) in charge of
pathogen elimination.
While most effector T cells die after the infection is resolved, a small part of this
population persists and differentiates into memory T cells (LTm CD8+). These cells provide
long term protection to the organism against the initial infectious agent. It is thus crucial to
have a better understanding of all mechanisms governing the development and the
maintenance of LTm CD8+.
Several studies have already shown that some members of the "C-dependent cytokines
family (IL-2, IL-7, IL-15 and IL-21) individually regulate LTe and LTm CD8+ development.
However, we believe that these cytokines have a far greater impact on the homeostasis of LTe
and LTm CD8+ than the current literature suggests. Indeed, we hypothesized that "C-dependant
cytokines act in synergy to promote the development of LTe and LTm CD8+.
To assess their effect, we first studied the combined impact of IL-2 and IL-15 signals on the
generation of LTe and LTm CD8+ during an LCMV Armstrong infection in mice. In this same
experimental model, we also studied the effect of a deficiency in IL-2, IL-15 and IL-21 signals
on the development of LTe and LTm CD8+. Our results show that these three cytokines
cooperate to support the expansion and differentiation of LTe CD8+. More accurately, IL-2,
IL-15 and IL-21 are essential for the homeostasis of a particular LTe CD8+ subset : Short-
Lived Effector Cells (SLECs). We also demonstrated that all three cytokines are required to
generate a maximal number of LTm CD8+. In addition, differentiation and maintenance of the
memory effector population (TEM) are substantially reduced in the combined absence of IL-2,
IL-15 and IL-21 signals.
These results are the first to our knowledge to highlight redundant and synergistic
functions of three "C-dependent cytokines as promoters of the development and maintenance
of LTe and LTm CD8+.
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Radiothérapie asservie à la respiration en combinaison avec l'utilisation d'un faisceau sans filtre égalisateurPéloquin, Simon 01 1900 (has links)
La radiothérapie stéréotaxique corporelle (SBRT) est une technique couramment employée
pour le traitement de tumeurs aux poumons lorsque la chirurgie n’est pas possible
ou refusée par le patient. Une complication de l’utilisation de cette méthode provient du
mouvement de la tumeur causé par la respiration. Dans ce contexte, la radiothérapie asservie
à la respiration (RGRT) peut être bénéfique. Toutefois, la RGRT augmente le temps
de traitement en raison de la plus petite proportion de temps pour laquelle le faisceau est
actif. En utilisant un faisceau de photons sans filtre égalisateur (FFF), ce problème peut
être compensé par le débit de dose plus élevé d’un faisceau FFF.
Ce mémoire traite de la faisabilité d’employer la technique de RGRT en combinaison
avec l’utilisation un faisceau FFF sur un accélérateur Synergy S (Elekta, Stockholm,
Suède) avec une ceinture pneumatique, le Bellows Belt (Philips, Amsterdam, Pays-Bas),
comme dispositif de suivi du signal respiratoire. Un Synergy S a été modifié afin de pouvoir
livrer un faisceau 6 MV FFF. Des mesures de profils de dose et de rendements en
profondeur ont été acquises en cuve à eau pour différentes tailles de champs. Ces mesures
ont été utilisées pour créer un modèle du faisceau 6 MV FFF dans le système de planification
de traitement Pinnacle3 de Philips. Les mesures ont été comparées au modèle à
l’aide de l’analyse gamma avec un critère de 2%, 2 mm. Par la suite, cinq plans SBRT
avec thérapie en arc par modulation volumétrique (VMAT) ont été créés avec le modèle
6 MV du Synergy S, avec et sans filtre. Une comparaison des paramètres dosimétriques
a été réalisée entre les plans avec et sans filtre pour évaluer la qualité des plans FFF. Les
résultats révèlent qu’il est possible de créer des plans SBRT VMAT avec le faisceau 6 MV
FFF du Synergy S qui sont cliniquement acceptables (les crières du Radiation Therapy
Oncology Group 0618 sont respectés).
Aussi, une interface physique de RGRT a été mise au point pour remplir deux fonctions
: lire le signal numérique de la ceinture pneumatique Bellows Belt et envoyer une
commande d’irradiation binaire au linac. L’activation/désactivation du faisceau du linac se
fait par l’entremise d’un relais électromécanique. L’interface comprend un circuit électronique
imprimé fait maison qui fonctionne en tandem avec un Raspberry Pi. Un logiciel
de RGRT a été développé pour opérer sur le Raspberry Pi. Celui-ci affiche le signal numérique
du Bellows Belt et donne l’option de choisir les limites supérieure et inférieure
de la fenêtre d’irradiation, de sorte que lorsque le signal de la ceinture se trouve entre
ces limites, le faisceau est actif, et inversement lorsque le signal est hors de ces limites.
Le logiciel envoie donc une commande d’irradiation au linac de manière automatique en
fonction de l’amplitude du signal respiratoire.
Finalement, la comparaison entre la livraison d’un traitement standard sans RGRT avec
filtre par rapport à un autre plan standard sans RGRT sans filtre démontre que le temps
de traitement en mode FFF est réduit en moyenne de 54.1% pour un arc. De la même
manière, la comparaison entre la livraison d’un traitement standard sans RGRT avec filtre
par rapport à un plan de RGRT (fenêtre d’irradiation de 75%) sans filtre montre que le
temps de traitement de RGRT en mode FFF est réduit en moyenne de 27.3% par arc.
Toutefois, il n’a pas été possible de livrer des traitements de RGRT avec une fenêtre de
moins de 75%. Le linac ne supporte pas une fréquence d’arrêts élevée. / Stereotactic body radiation therapy (SBRT) is a technique commonly employed for
treatment of lung tumors when surgery is not possible or not accepted by the patient. One
complication arising from the use of this method comes from the movement of the tumor
during respiration. In this context, respiratory gated radiation therapy (RGRT) can be
beneficial. By using a flattening filter free (FFF) photon beam, the increase in treatment
time caused by a reduced beam-on time of respiratory gated methods can be compensated
by the inherent increased dose rate of FFF beams.
This thesis reports on the feasibility of using the RGRT technique in combination with
the use of a FFF photon beam on a Synergy S (Elekta, Stockholm, Sweden) linear accelerator
with a pneumatic belt, the Bellows Belt (Philips, Amsterdam, Netherlands), to
monitor the patient’s respiratory signal. A Synergy S has been modified to deliver a 6 MV
FFF photon beam. Dose profile and percentage depth dose measurements were taken in
a water tank for different field sizes. Those measurements were used to create a model
for the 6 MV FFF beam with the Pinnacle3 treatment planning system from Philips. Measurements
were compared with the model using gamma index analysis with a 2%, 2 mm
criterion. Then, five SBRT plans with volumetric modulated arc therapy (VMAT) were
created in Pinnacle3 with the 6 MV Synergy S model, with and without a flattening filter.
A comparison of dosimetric parameters was made between plans with and without a flattening
filter to estimate the quality of the FFF plans. Results reveal that it is possible to
create SBRT VMAT plans with the 6 MV FFF model of the Synergy S that are clinically
acceptable (criteria of the Radiation Therapy Oncology Group 0618 were respected).
Also, a RGRT hardware interface was created to fulfill two main functions: read the
digital signal from the Bellows Belt pneumatic belt and send an on/off irradiation command
to the linac. The activation/deactivation of the beam is regulated by an electromechanical
relay. The interface is composed of a homemade printed circuit board that functions with a Raspberry Pi. A RGRT software was also developed to operate on the Raspberry
Pi. This software shows the Bellows Belt’s digital signal and gives the option of
choosing the upper and lower limits of the gating window. When the respiratory signal
of the belt is between those limits, the beam is active, and vice versa when the signal is
outside those limits. The software thus effectively sends an on/off irradiation command
automatically to the linac depending on the amplitude of the respiratory signal.
Finally, a comparison between the delivery of a standard plan without RGRT, with
filter, and another standard plan without RGRT, without filter, shows that the treatment
time for plans using the FFF beam is reduced by 54.1% on average for one arc. Similarly,
a comparison between the delivery of a standard plan without RGRT, with filter, and a
gated plan (gating window of 75%), without filter, shows that the treatment time for the
gated treatments is reduced by 27.3% on average for one arc. However, it was not possible
to deliver RGRT treatments with a gating window smaller than 75%. The linac does not
support such a high frequency of beam halting.
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Investigating the encoding of visual stimuli by forming neural circuits in the cat primary visual cortexBharmauria, Vishal 04 1900 (has links)
Contexte
La connectomique, ou la cartographie des connexions neuronales, est un champ de recherche des neurosciences évoluant rapidement, promettant des avancées majeures en ce qui concerne la compréhension du fonctionnement cérébral. La formation de circuits neuronaux en réponse à des stimuli environnementaux est une propriété émergente du cerveau. Cependant, la connaissance que nous avons de la nature précise de ces réseaux est encore limitée. Au niveau du cortex visuel, qui est l’aire cérébrale la plus étudiée, la manière dont les informations se transmettent de neurone en neurone est une question qui reste encore inexplorée. Cela nous invite à étudier l’émergence des microcircuits en réponse aux stimuli visuels. Autrement dit, comment l’interaction entre un stimulus et une assemblée cellulaire est-elle mise en place et modulée?
Méthodes
En réponse à la présentation de grilles sinusoïdales en mouvement, des ensembles neuronaux ont été enregistrés dans la couche II/III (aire 17) du cortex visuel primaire de chats anesthésiés, à l’aide de multi-électrodes en tungstène. Des corrélations croisées ont été effectuées entre l’activité de chacun des neurones enregistrés simultanément pour mettre en évidence les liens fonctionnels de quasi-synchronie (fenêtre de ± 5 ms sur les corrélogrammes croisés corrigés). Ces liens fonctionnels dévoilés indiquent des connexions synaptiques putatives entre les neurones. Par la suite, les histogrammes peri-stimulus (PSTH) des neurones ont été comparés afin de mettre en évidence la collaboration synergique temporelle dans les réseaux fonctionnels révélés. Enfin, des spectrogrammes dépendants du taux de décharges entre neurones ou stimulus-dépendants ont été calculés pour observer les oscillations gamma dans les microcircuits émergents. Un indice de corrélation (Rsc) a également été calculé pour les neurones connectés et non connectés.
Résultats
Les neurones liés fonctionnellement ont une activité accrue durant une période de 50 ms contrairement aux neurones fonctionnellement non connectés. Cela suggère que les connexions entre neurones mènent à une synergie de leur inter-excitabilité. En outre, l’analyse du spectrogramme dépendant du taux de décharge entre neurones révèle que les neurones connectés ont une plus forte activité gamma que les neurones non connectés durant une fenêtre d’opportunité de 50ms. L’activité gamma de basse-fréquence (20-40 Hz) a été associée aux neurones à décharge régulière (RS) et l’activité de haute fréquence (60-80 Hz) aux neurones à décharge rapide (FS). Aussi, les neurones fonctionnellement connectés ont systématiquement un Rsc plus élevé que les neurones non connectés. Finalement, l’analyse des corrélogrammes croisés révèle que dans une assemblée neuronale, le réseau fonctionnel change selon l’orientation de la grille. Nous démontrons ainsi que l’intensité des relations fonctionnelles dépend de l’orientation de la grille sinusoïdale. Cette relation nous a amené à proposer l’hypothèse suivante : outre la sélectivité des neurones aux caractères spécifiques du stimulus, il y a aussi une sélectivité du connectome. En bref, les réseaux fonctionnels «signature » sont activés dans une assemblée qui est strictement associée à l’orientation présentée et plus généralement aux propriétés des stimuli.
Conclusion
Cette étude souligne le fait que l’assemblée cellulaire, plutôt que le neurone, est l'unité fonctionnelle fondamentale du cerveau. Cela dilue l'importance du travail isolé de chaque neurone, c’est à dire le paradigme classique du taux de décharge qui a été traditionnellement utilisé pour étudier l'encodage des stimuli. Cette étude contribue aussi à faire avancer le débat sur les oscillations gamma, en ce qu'elles surviennent systématiquement entre neurones connectés dans les assemblées, en conséquence d’un ajout de cohérence. Bien que la taille des assemblées enregistrées soit relativement faible, cette étude suggère néanmoins une intrigante spécificité fonctionnelle entre neurones interagissant dans une assemblée en réponse à une stimulation visuelle. Cette étude peut être considérée comme une prémisse à la modélisation informatique à grande échelle de connectomes fonctionnels. / Background
‘Connectomics’— the mapping of neural connections, is a rapidly advancing field in neurosciences and it promises significant insights into the brain functioning. The formation of neuronal circuits in response to the sensory environment is an emergent property of the brain; however, the knowledge about the precise nature of these sub-networks is still limited. Even at the level of the visual cortex, which is the most studied area in the brain, how sensory inputs are processed between its neurons, is a question yet to be completely explored. Heuristically, this invites an investigation into the emergence of micro-circuits in response to a visual input — that is, how the intriguing interplay between a stimulus and a cell assembly is engineered and modulated?
Methods
Neuronal assemblies were recorded in response to randomly presented drifting sine-wave gratings in the layer II/III (area 17) of the primary visual cortex (V1) in anaesthetized cats using tungsten multi-electrodes. Cross-correlograms (CCGs) between simultaneously recorded neural activities were computed to reveal the functional links between neurons that were indicative of putative synaptic connections between them. Further, the peristimulus time histograms (PSTH) of neurons were compared to divulge the epochal synergistic collaboration in the revealed functional networks. Thereafter, perievent spectrograms were computed to observe the gamma oscillations in emergent microcircuits. Noise correlation (Rsc) was calculated for the connected and unconnected neurons within these microcircuits.
Results
The functionally linked neurons collaborate synergistically with augmented activity in a 50-ms window of opportunity compared with the functionally unconnected neurons suggesting that the connectivity between neurons leads to the added excitability between them. Further, the perievent spectrogram analysis revealed that the connected neurons had an augmented power of gamma activity compared with the unconnected neurons in the emergent 50-ms window of opportunity. The low-band (20-40 Hz) gamma activity was linked to the regular-spiking (RS) neurons, whereas the high-band (60-80 Hz) activity was related to the fast-spiking (FS) neurons. The functionally connected neurons systematically displayed higher Rsc compared with the unconnected neurons in emergent microcircuits. Finally, the CCG analysis revealed that there is an activation of a salient functional network in an assembly in relation to the presented orientation. Closely tuned neurons exhibited more connections than the distantly tuned neurons. Untuned assemblies did not display functional linkage. In short, a ‘signature’ functional network was formed between neurons comprising an assembly that was strictly related to the presented orientation.
Conclusion
Indeed, this study points to the fact that a cell-assembly is the fundamental functional unit of information processing in the brain, rather than the individual neurons. This dilutes the importance of a neuron working in isolation, that is, the classical firing rate paradigm that has been traditionally used to study the encoding of a stimulus. This study also helps to reconcile the debate on gamma oscillations in that they systematically originate between the connected neurons in assemblies. Though the size of the recorded assemblies in the current investigation was relatively small, nevertheless, this study shows the intriguing functional specificity of interacting neurons in an assembly in response to a visual input. One may form this study as a premise to computationally infer the functional connectomes on a larger scale.
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Položkové ocenění ekonomické rozvahy a jeho konzistence. / Itemized valuation of the econonomic balance sheetJindra, Marek January 2008 (has links)
The dissertation thesis deals with valuation of individual items in the economic balance sheet of a stand-alone company and subsequently as a part of acquisition. We define the economic balance sheet as a full set of assets, liabilities as well as synergies amongst the assets (stand-alone company view) and companies (transaction view), where the sum of their individual valuations has to equal to the overall value of the company. Hence we suggest that the management (and a valuer) should be able to decompose the company value into defined and controllable value components. Apart from identifying optimal methods for the individual valuation, the key for achieving this task is the internal (amongst the assets) as well as the overall consistency (vis-a-vis the overall company value). Compared to the overall-valuation approach, we demonstrate how the component approach can lead to more precise results, higher management discipline and accountability, and can serve as a tool for an a priori identification of overpayment as well as an instrument for controlling the value post transaction. We defined two primary types of synergies in terms of valuation approach - Enhancement, improving current income potential and Future opportunities, mainly focusing on new projects - and proposed appropriate valuation approaches given their specifics. Since a large proportion of valuations on individual level is based on the income approach, setting a clear and consistent approach to discount rates was a vital part of the work. We propose a primary and, if not available, second-best rate for each component of the economic balance sheet. Although the synergies are probably of the highest commercial interest, the liabilities with external source of risk and deferred taxes on the individual level are areas generally neglected both by academics and practitioners. While the first one will have only but crucial impact on companies with decommissioning and similar liabilities, the latter is present almost in any itemized valuation, and its incorrect or purely isolated application affects the overall result and breaks the link to the overall company value. We analyze both topics and offer consistent valuation methods, although further research is required to refine them. We discuss WARA as one of the key tools for ensuring consistency of itemized valuation of the economic balance sheet. Lacking any theoretical background and interest from academic researchers, we first analyze simple concepts of the tool as they are used in practice and point out observed conceptual errors, oversimplifications and accounting-only approach. Not only that we propose complex consistent rules for WARA construction but we extend the concept from the focus on conventionally defined net assets to the full economic balance sheet, which is the only way how to relate the itemized valuation to the overall company valuation. Finally, we presented a case study based on real-life example which demonstrated practical applicability of proposed partial solutions as well as the overall approach to achieving consistency with the total company or transaction valuation. Although the analysis of individual items of the economic balance will be inevitably based on subjective assumptions to an extent, we have shown that proposed complex and consistent approach adds value to the strategic and transaction considerations. Also the preciseness of the tools will increase with the number of transactions performed as the parameters get calibrated.
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Design and optimisation of innovative electronic cooling heat sinks with enhanced thermal performances using numerical and experimental methods / Conception et optimisation de dissipateurs thermiques de refroidissement électronique innovantsMehra, Bineet 08 March 2019 (has links)
Cette thèse de doctorat s’intéresse aux mécanismes d’amélioration des transferts dans des géométries de dissipateurs thermiques à plaques et ailettes. Une première partie est consacrée à l’étude d’une configuration académique à l’aide de simulations numériques visant à obtenir une amélioration du transfert de chaleur conjugué en modifiant uniquement par des découpes la forme géométrique des ailettes planes conductrices. Une analyse locale approfondie de l’écoulement et des champs thermiques a été effectuée avec notamment le principe de synergie locale, des champs de vitesse et de gradients thermiques, pour comprendre l’effet des modifications géométriques. Ce mémoire présente également le développement de dissipateurs aux performances thermo-aérauliques augmentées pour des applications de refroidissement de coffrets électronique embarqués. L’intensification des transferts thermiques est obtenue par la génération d’écoulements secondaires qui provoquent un brassage de fluide et réduisent la résistance thermique à la paroi en perturbant le développement de la couche limite thermique. Différentes configurations de dissipateurs avec deux types de générateurs d’écoulements secondaires, paires d’ailettes Delta et protrusions, ont été étudiées numériquement, en employant une modélisation de type « RANS ». Les performances thermo-aérauliques des géométries munies de générateurs de vorticité ont été comparées à celle d’un dissipateur thermique de référence « lisse ». Des prototypes ont également été fabriqués et testés sur un banc expérimental spécifiquement développé pour réaliser des mesures des performances globales en termes de puissance thermique et de pertes de charge. Les résultats expérimentaux et numériques ont été confrontés afin de qualifier les simulations réalisées. Par la suite, une étude d’optimisation employant l’analyse factorielle Taguchi a été utilisée afin d’optimiser les paramètres géométriques des dissipateurs retenus. Deux fonctions objectif ont été considérées : la maximisation du facteur de performance thermique à iso puissance de ventilation (PEC) et la réduction de la température moyenne de paroi du dissipateur par rapport au cas de référence. L’analyse des performances thermo-aérauliques globales des géométries étudiées a été complétée par une analyse qualitative locale des champs thermiques et d’écoulement notamment avec le principe de synergie. / This doctoral thesis focuses on mechanisms of heat transfer enhancement in plate and fin heat sink geometries. First part of the thesis is dedicated to study an academic configuration using numerical simulations to achieve an improvement in conjugate heat transfer by modifying only the geometrical shape (through punching) of the conductive plane fins. An in-depth local analysis of the flow and thermal fields was carried out with the local synergy principle, velocity and thermal gradients, to understand the effect of geometric modifications. This thesis also presents the development of heat sinks with increased thermo-hydraulic performance for on-board electronic box cooling applications. The intensification of the heat transfer is obtained by the generation of secondary flows which cause an intensive mixing of fluid and reduces the thermal resistance to the wall by disrupting the development of the thermal boundary layer. Different heat sink geometries with two types of secondary flow generators : delta winglet pair and protrusions were numerically studied using RANS approach. The thermo-hydraulic performances of the geometries equipped with vortex generators were compared with that of a smooth reference heat sink. The prototypes were also manufactured and tested on an experimental bench specifically designed to perform global performance measurements in terms of thermal power and pressure drops. Experimental and numerical results were compared to qualify the simulations performed. Subsequently, an optimization study using Taguchi factorial analysis was used to optimize the geometrical parameters of the chosen dissipaters. Two objective functions were considered : maximization of either iso-pumping power performance criteria (PEC) or average wall temperature of the dissipaters compared to the reference case. The global thermo-hydraulic performance analysis of the studied geometries was completed by a qualitative analysis of local flow and thermal fields, in particular with the local field synergy principle.
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