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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Výskyt biogenních aminů a polyaminů ve zrajících sýrech po ukončení doby spotřeby / Content of biogenic amines and polyamines in expired ripening cheeses

VODEHNALOVÁ, Klára January 2012 (has links)
The aim of this thesis was to observe the occurrence of biogenic amines and polyamines in selected types of ripening cheeses and to assess the content of the materials since the expiration date. Content of biogenic amines and polyamines in chosen samples was monitored last day of the expiration date, a week after the expiration date, two weeks after the expiration date, and after four weeks from the end of the expiration date.
22

Participação dos neurônios noradrenérgicos do Locus Coeruleus na geração central das atividades inspiratória e expiratória em resposta à ativação dos quimiorreceptores centrais de ratos / Participation of the noradrenergic neurons of Locus Coeruleus in the central generation of inspiratory and expiratory activities in response to the activation of the central chemoreceptors of rats

Magalhães, Karolyne Silva 25 February 2019 (has links)
Em condições basais a inspiração é um fenômeno ativo enquanto a expiração é um fenômeno passivo. Em condições de desafios metabólicos, como aumento da pressão parcial de CO2 e da [H+] no sangue arterial (hipercapnia/acidose), ocorre aumento da atividade inspiratória, a expiração passa a ser ativa, produzindo aumentos da atividade dos músculos abdominais, e a resistência das vias aéreas superiores reduz. O Locus Coeruleus (LC) contém neurônios noradrenérgicos (NE) que aumentam sua frequência de potenciais de ação quando expostos a elevados níveis de CO2/[H+] e se comunicam com os neurônios respiratórios do tronco encefálico para fazer ajustes compensatórios na ventilação pulmonar durante a hipercapnia/acidose. Utilizando preparações in situ de ratos avaliamos a contribuição dos neurônios NE do LC na geração central das atividades inspiratória e expiratória e no controle da resistência das vias aéreas superiores em condições basais e em resposta a hipercapnia/acidose. Neurônios NE do LC foram seletivamente silenciados de maneira aguda e reversível pela aplicação do peptídeo de inseto alatostatina (Alst) após a transfecção celular utilizando um vetor lentiviral para expressão de receptores de Drosophila para a Alst acoplados a proteína G inibitória (AlstR). Dez a doze dias após, realizamos a abordagem dorsal da preparação in situ de ratos. Os nervos frênico (PN), abdominal (AbN), hipoglosso (HN) e vago cervical (cVN) foram registrados e analisados em diferentes fases do ciclo respiratório. Registros extracelulares single unit dos neurônios do LC também foram realizados. A frequência respiratória (fR), a duração da inspiração (DI) e da expiração (DE), a expiração ativa, a magnitude da modulação respiratória e a frequência de potenciais de ação dos neurônios do LC também foram avaliadas. A inibição seletiva dos neurônios NE do LC usando Alst não provocou alterações significativas na atividade dos motores nervos respiratórios, na fR, DI e DE em normocapnia. A inibição desses neurônios antes e/ou durante à hipercapnia/acidose reduziu significantemente a amplitude do AbN e em alguns momentos, eliminou a expiração ativa, além de reduzir as respostas inspiratórias do PN e HN (amplitude) e a atividade pós-inspiratória (adução da glote) do cVN. Quandoda ausência da expiração ativa após a inibição dos neurônios NE do LC, a DI, DE e a duração da atividade pré-inspiratória do cVN (abdução da glote) e HN (protusão da língua) foram normalizadas. A adição de Alst em preparações in situ de ratos que não expressavam o AsltR durante a hipercapnia/acidose não causou alterações no padrão dos nervos motores respiratórios registrados, na incidência da expiração ativa e na fR, DI e DE. Entre os neurônios do LC registrados, encontramos três populações com diferentes padrões de modulação pela respiração e uma com atividade tônica. A hipercapnia/acidose aumentou a magnitude da modulação respiratória e a frequência de potenciais de ação destas populações neuronais. Esses dados demonstram que os neurônios NE do LC exercem importante papel modulatório excitatório na geração central da inspiração, expiração ativa e no controle da resistência das vias aéreas superiores evocados pela hipercapnia/acidose em preparações in situ de ratos / In basal conditions, inspiration is an active phenomenon while expiration is a passive phenomenon. Under conditions of high metabolic demands, such as increased in partial pressure of CO2 and [H+] in arterial blood (hypercapnia/acidosis), there is an increase in inspiratory activity, expiration becomes active, producing increases in abdominal muscle activity, and the resistance of the upper airways reduces. The Locus Coeruleus (LC) contains noradrenergic (NE) neurons that increase their firing frequency when exposed to elevated CO2/[H+] levels and communicate with respiratory brainstem neurons to make compensatory adjustments in lung ventilation during hypercapnia/acidosis. Using in situ preparations of rats, we evaluated the contribution of LC NE neurons in the central generation of inspiratory and expiratory activities, as well as in the control of upper airway resistance in basal conditions and in response to hypercapnia/acidosis. LC NE neurons were selectively acutely and reversibly silenced by application of the insect allatostatin peptide (Alst) after cellular transfection using a lentiviral vector for expression of Alst Drosophila receptors coupled to inhibitory G protein (AlstR). Ten to twelve days after, we performed the dorsal approach of the in situ preparation of rats. The phrenic (PN), abdominal (AbN), hypoglossal (HN) and cervical vagus (cVN) nerves were recorded and analyzed in different phases of the respiratory cycle. Single unit extracellular records of LC neurons were also performed. Respiratory frequency (fR), duration of inspiration (DI) and expiration (DE), active expiration, the magnitude of respiratory modulation and the firing frequency of LC neurons were also evaluated. Selective inhibition of LC NE neurons using Alst did not produce significant changes in the activity of respiratory motor nerves, fR, DI and DE in normocapnia. Inhibition of these neurons before and/or during hypercapnia/acidosis significantly reduced AbN amplitude and its incidence, as well as the inspiratory responses of PN and HN (amplitude) and post-inspiratory activity (glottal adduction) of the cVN. In the absence of active expiration after the inhibition of LC NE neurons, the DI, DE and the pre-inspiratory activity of cVN (glottal abduction) and HN (tongue protrusion) were normalized. The perfusion of Alst in in situ preparations of rats withoutthe expression of the AsltR during hypercapnia/acidosis did not change the pattern of the recorded respiratory motor nerves, the incidence of active expiration, fR, DI and DE. Among the registered LC neurons, we found three populations with different patterns of respiratory modulation and one with tonic activity. Hypercapnia/acidosis increased the magnitude of the respiratory modulation and their firing frequency. These data demonstrate that LC NE neurons exert an important excitatory modulatory role in the central generation of inspiration, active expiration and in the control of upper airway resistance evoked by hypercapnia/acidosis in in situ preparations of rats
23

A Study of Open Code Dating in Grocery Retailing in Dallas County

McGown, Kirby Lee 12 1900 (has links)
This study deals with "open code dating," the movement by grocery manufacturers and distributors toward dating perishable food packages in such a manner that consumers can readily determine product freshness or length of time on store shelves. The study explores the desirability and feasibility of open code dating, placing greatest importance upon the response of the consumer to the concept. It was found that consumers were aware of open code dating and generally strongly desired its universal adoption. Shoppers were also confused by open dating and failed to understand freshness dates properly. The strongest desire for open dating was found in shoppers at the upper end of the socio-economic scale. Grocery retailers expressed satisfaction with open coding, believing it an aid in stock rotation and customer satisfaction. Possible disadvantages, such as increased throwaway costs and large conversion costs, were not perceived as being significant. The businessmen favored widespread adoption of open code dating. On the basis of data from interviews with shoppers, it is concluded that consumers desire adoption of open code dating and do use this service. It is also concluded that adoption of open code dating would be an economically sound decision which would constitute a desirable marketing strategy.
24

股票選擇權採現金交割之可行性分析 / The Possibility Analysis of Adopting Cash Settlement for Stock Options in Taiwan Market

任俊行, Jen, Chun-Hsing Unknown Date (has links)
台灣期貨交易所於92年1月20日推出到期採實物交割的股票選擇權契約,希望能提供市場更豐富、更多元的避險以及套利機能。然自股票選擇權推出以來,市場成交量並未如預期般蓬勃發展,便失去台灣期貨交易所推出股票選擇權之用意,不能使其充分發揮其多元之避險套利機能。多數人主觀認為,採用現金交割方式的衍生性金融商品容易受到人為操縱。一般而言,研究市場的人為操縱因子多以報酬波動率及到期日效應作為觀察指標,因此商品之交割方式與報酬波動率及到期日效應有一定之關聯。然而近來國外許多相關研究發現,採實物交割與現金交割,對股票選擇權的到期日效應並未產生差異,反而是透過結算制度的設計,可以有效降低人為操縱的機率。本研究旨在研究股票選擇權改採現金交割之可行性分析,研究到期日採現金交割是否就是增加人為操縱機率的主要因素,且到期日效應與到期交割方式是否又有絕對的關係?而根據文獻了解,到期日報酬波動率與受人為操縱之跡象是呈現正向關係。 / 因此本研究對指數期貨在到期日與非到期日時對指數現貨價格以及個股股價報酬波動率的影響程度進行實證分析,以報酬波動率之異常現象判斷是否有所謂到期日效應。 本研究實證結果指出,在台指期貨到期日報酬波動率和摩根台指期貨到期日的報酬波動率實證結果發現所有樣本在台指期貨到期日的報酬波動率都顯著高於摩根台指期貨到期日的報酬波動率。顯示台指期貨結算制度雖為到期日下一交易日開盤前十五分鐘個股成交量加權平均價結算,但並未有效降低異常報酬波動率的發生。根據國外研究結果發現,個股期貨能降低到期日效應之影響。此外,採實物交割與現金交割,對股票選擇權的到期日效應並未產生差異。為了降低到期日效應且提升市場的效率性,建議股票選擇權改為現金交割之外,尚可考慮開放個股期貨的交易。 / Taiwan Futures Exchange launched stock options on January 20, 2003, hoping to provide the market with more hedging and arbitraging opportunities. However, the trading volume does not grow as was expected. The low trading volume does not meet Taiwan Futures Exchange’s goal to provide the market with hedging and arbitraging mechanism. Most people think that derivatives applying cash settlement lead to manipulation. Researchers studying manipulations take the volatility of returns and expiration effects as the factors of their studies. However, some recent studies suggest applying cash settlement or physical settlement does not have much impact on expiration effects, while applying proper settlement system can reduce manipulation. / This research investigated the possibility of stock options applying cash settlement and examined the volatility of returns of stock indexes and stock prices during settlement and non-settlement days to determine if expiration effects exist. In this study, we found the volatilities of returns of all samples during TAIFEX settlement days are significantly higher than the volatilities of returns during SIMEX settlement days. All of our samples have significant higher volatilities of returns during TAIFEX settlement days and SIMEX settlement days except CMO, which does not have significant higher volatility of returns during SIMEX settlement days. Other researches point out the adopting of stock futures reduces the expiration effects. Furthermore, adopting cash settlement or physical settlement does have much impact on expiration effects. To decrease the expiration effect and to increase the effectiveness of the market, this study proposes the adoption of cash settlement and the launching of stock futures.
25

Obligations Regime of the Mining Concession (Mining rights system) / Régimen de Obligaciones de la Concesión Minera (Amparo Minero)

Martínez Aponte, Humberto 10 April 2018 (has links)
Mining concessions are subject to the fulfillment of liabilities by their owners based on ground for revocation, known as «expiration», as part of mining rights systems. The recent evolution of these liabilities and their focus as part of the conditions offered by the country for investment are analyzed by the author. To do this, the author conduct a review about the changes taken place in 1991 and 2008 mainly, as well as provides the elements to analyze the appropriateness of modifications or its flexibility. The tables used in the explanation constitutes a contribution, which were used by the author in conferences and due diligence for mining projects, as well as the consideration of both elements in the analysis of doctrine and real application of these concepts under the system of Peru. / Las concesiones mineras están sujetas al cumplimiento de obligaciones por sus titulares, bajo causal de revocación, conocida como la «caducidad», enmarcadas en sistemas de amparo minero. La evolución reciente de estas obligaciones, así como enfocarlas como parte de las condiciones que ofrece el país para la inversión, son analizados por el autor. Para ello, realiza una revisión de las modificaciones ocurridas en 1991 y 2008 principalmente, así también proporciona los elementos para reflexionar sobre la conveniencia de nuevas modificaciones o de su flexibilización. Constituyen un aporte los cuadros empleados en la explicación, utilizados por el autor tanto en conferencias, como en due diligence en proyectos mineros; así como considerar en el análisis tanto elementos de doctrina, como de aplicación real deestos conceptos en el régimen del Perú.
26

1D model for flow in the pulmonary airway system

Alahmadi, Eyman Salem M. January 2012 (has links)
Voluntary coughs are used as a diagnostic tool to detect lung diseases. Understanding the mechanics of a cough is therefore crucial to accurately interpreting the test results. A cough is characterised by a dynamic compression of the airways, resulting in large flow velocities and producing transient peak expiratory flows. Existing models for pulmonary flow have one or more of the following limitations: 1) they assume quasi-steady flows, 2) they assume low speed flows, 3) they assume a symmetrical branching airway system. The main objective of this thesis is to develop a model for a cough in the branching pulmonary airway system. First, the time-dependent one-dimensional equations for flow in a compliant tube is used to simulate a cough in a single airway. Using anatomical and physiological data, the tube law coupling the fluid and airway mechanics is constructed to accurately mimic the airway behaviour in its inflated and collapsed states. Next, a novel model for air flow in an airway bifurcation is constructed. The model is the first to capture successfully subcritical and supercritical flows across the bifurcation and allows for free time evolution from one case to another. The model is investigated by simulating a cough in both symmetric and asymmetric airway bifurcations. Finally, a cough model for the complete branching airway system is developed. The model takes into account the key factors involved in a cough; namely, the compliance of the lungs and the airways, the coughing effort and the sudden opening of the glottis. The reliability of the model is assessed by comparing the model predictions with previous experimental results. The model captures the main characteristics of forced expiatory flows; namely, the flow limitation phenomenon (the flow out of the lungs becomes independent of the applied expiratory effort) and the negative effort dependence phenomenon (the flow out of the lungs decreases with increasing expiratory effort). The model also gives a good qualitative agreement with the measured values of airway resistance. The location of the collapsed airway segment during forced expiration is, however, inconsistent with previous experimental results. The effect of changing the model parameters on the model predictions is therefore discussed.
27

The impact of expiration date tracking software in grocery stores : A task-technology fit review of information systems used for date-checking in grocery stores

Enstam, Anna January 2022 (has links)
Each year, 1.3 billion tons of food produced for human consumption are lost or go to waste globally throughout the food supply chain (FSC). Increasing the efficiency of the entire FSC is an essential action in achieving food security for the global population, which includes reducing the amount of food lost and wasted. This thesis aims to contribute with rich insight into if and how contemporary information systems in grocery stores, which are part of the FSC, are supporting expiration date tracking and if they are contributing to reducing food waste. The study was carried out as a case study in three grocery stores, applying the task-technology fit model as its theoretical framework to guide the study and analyze the empirical results. The study found that the expiration date tracking systems in the grocery stores supported them in tracking expiration dates considering the measurements of task-technology fit since they sufficiently support and fulfill the needs of the users’ tasks, but that there is still room for improvement. The study also found that, according to the users’ perceptions, the grocery stores using expiration date tracking systems were able to prevent more food waste when using the systems in comparison to if they would not have been used.
28

Public certificate management : An analysis of policies and practices used by CAs / Offentlig certifikathantering : En analys av policys och praxis som används av CAs

Bergström, Anna, Berghäll, Emily January 2021 (has links)
Certificate Authorities (CAs) carry a huge responsibility in today's internet security landscape as they issue certificates that establish secure end-to-end connections. This thesis conducts a policy review and survey of CAs' Certificate Policies and Certificate Practice Statements to find similarities and differences that could lead to possible vulnerabilities. Based on this, the thesis then presents a taxonomy-based analysis as well as comparisons of the top CAs to the Baseline Requirements. The main areas of the policies that were focused on are the issuance, revocation and expiration practices of the top 30 CAs as determined by the use of Tranco's list. We also determine the top CA groups, meaning the CAs whose policies are being used by the most other CAs as well as including a top 100 CAs list. The study suggests that the most popular CAs hold such a position because of two main reasons: they are easy to acquire and/or because they are connected to several other CAs.  The results suggest that some of the biggest vulnerabilities in the policies are what the CAs do not mention in any section as it puts the CA at risk for vulnerabilities. The results also suggest that the most dangerous attacks are social engineering attacks, as some of the stipulations for issuance and revocations make it possible to pretend to be the entity of subscribes to the certificate rather than a malicious one.
29

Algorithmic Trading and Prediction of Foreign Exchange Rates Based on the Option Expiration Effect / Algoritmisk handel och prediktion av valutakurser baserade på effekten av FX-optioners förfall

Mozayyan Esfahani, Sina January 2019 (has links)
The equity option expiration effect is a well observed phenomenon and is explained by delta hedge rebalancing and pinning risk, which makes the strike price of an option work as a magnet for the underlying price. The FX option expiration effect has not previously been explored to the same extent. In this paper the FX option expiration effect is investigated with the aim of finding out whether it provides valuable information for predicting FX rate movements. New models are created based on the concept of the option relevance coefficient that determines which options are at higher risk of being in the money or out of the money at a specified future time and thus have an attraction effect. An algorithmic trading strategy is created to evaluate these models. The new models based on the FX option expiration effect strongly outperform time series models used as benchmarks. The best results are obtained when the information about the FX option expiration effect is included as an exogenous variable in a GARCH-X model. However, despite promising and consistent results, more scientific research is required to be able to draw significant conclusions. / Effekten av aktieoptioners förfall är ett välobserverat fenomen, som kan förklaras av delta hedge-ombalansering och pinning-risk. Som följd av dessa fungerar lösenpriset för en option som en magnet för det underliggande priset. Effekten av FX-optioners förfall har tidigare inte utforskats i samma utsträckning. I denna rapport undersöks effekten av FX-optioners förfall med målet att ta reda på om den kan ge information som kan användas till prediktioner av FX-kursen. Nya modeller skapas baserat på konceptet optionsrelevanskoefficient som bestämmer huruvida optioner har en större sannolikhet att vara "in the money" eller "out of the money" vid en specificerad framtida tidpunkt och därmed har en attraktionseffekt. En algoritmisk tradingstrategi skapas för att evaluera dessa modeller. De nya modellerna baserade på effekten av FX-optioners förfall överpresterar klart jämfört med de tidsseriemodeller som användes som riktmärken. De bästa resultaten uppnåddes när informationen om effekten av FX-optioners förfall inkluderas som en exogen variabel i en GARCH-X modell. Dock, trots lovande och konsekventa resultat, behövs mer vetenskaplig forskning för att kunna dra signifikanta slutsatser.
30

Urban Hospice: A Montage of Expiration and Memory

Finney, Timothy John 23 May 2007 (has links)
Architecture is visuality. Its object is what Norman Bryson has referred to as a screen of signs. "Between subject and the world is inserted the entire sum of discourses which make up visuality, that cultural construct, and make visuality different from vision, the notion of unmediated visual experience. Between retina and the world is inserted a screen of signs, a screen consisting of all the multiple discourses on vision built into the social arena." (Norman Bryson, from Practice; Architecture, Technique, and Representation, by Stan Allen) Architecture and representation are integral to the screen. How do we make architecture? Is the act of making architecture a montage? Can architecture be made through montage? What is the role of montage in an architecture for life and death? The process of making architecture is not a prescribed methodology with a predetermined outcome. Architecture, crafted by the hand of the architect, is a divine act of assemblage of subconscious allegorical thought, image, and tectonics. Through this art of assemblage, an architecture is born capable of instigating a narrative of metaphor and memory. Metaphorical narrative has the innate ability of summoning memory, and is critical in an architecture for life and death. Architecture is the only total sensory means of narrative. / Master of Architecture

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