• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 33
  • 25
  • 11
  • 6
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • Tagged with
  • 103
  • 103
  • 14
  • 14
  • 14
  • 13
  • 11
  • 7
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • 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.
31

Seasonal Market Trends for Feeder and Stocker and for Slaughter Steers for the Years 1940 through 1948

Embry, J.C. 06 1900 (has links)
Standing on the threshold of a new decade, Texas agriculture is faced with three major problems. The first of these problems is the imperative need for a sound soil and water conservation program. Texas has been struggling with this problem for fifty years and has made some progress toward its solution. During the war, however, it was an all-out production of food regardless of cost, either in terms of dollars or resources. As a result, the conservation problem is more acute today than ever before. The second problem is that farm production is out of balance. Lucrative prices for oil and grain crops, plus the increasing shortage of farm labor, turned thousands of farmers from the more stable diversified farm program which had been built up during the '30s. Now, they are again faced with quotas and acreage allotments. This calls for necessarily early and probably extensive readjustment of the entire agricultural production program. The third major change in the agricultural picture is the rapid industrialization of Texas during and since the war. This increase in urban population in this state means an increased market right at the farmer's door for more livestock, dairy, poultry, fruit, and vegetable production. Fortunately, the solution of these three problems is found in one answer. Pasture grass, forage crops, and legumes provide the best means of soil and water conservation and soil building. Inclusion of these crops in a diversified and balanced cropping program will solve the problem of marketing quotas and acreage allotments. Marketing through livestock will provide the abundance of these foods which is needed to meet the growing demands of Texas markets.
32

Seasonal variations in general activity, behaviour and cutaneous glandular structures in reindeer (Rangifer tarandus L.)

Mossing, Torgny January 1980 (has links)
The locomotor activity of the reindeer is separated into a diurnal and a nocturnal phase which, in turn, consists of a  number of short-term activity bursts. The onset and termination  of diurnal and nocturnal activity are largely in synchrony  with sunrise and sunset. Since the diurnal phase is  longer, total activity is dependent on the photoperiod. Total  activity as well as the number of activity bursts is greater  in Jùne with continuous daylight than in December with 6  hours daylight. In winter, reindeer spent less time feeding  but more time ruminating and resting *than in summer. Synchronization  between individuals was also greatest in winter. It  is concluded that the described changes in the activity  pattern are due to an endogenous component and that this component  further controls food consumption and energy balance  of the reindeer.  Seasonal variations in behavioural patterns are described.  Several specific rutting behavioürs, sexual and agonostic,  emerge in the male during the prerut and persist until after  the rut. The preorbital gland is enlarged and secretory activity  is evident. The rut is cha'tabterized by the sudden appearance  of an odour in the breath of mature males followed a few  later by a strong odour in the urine. These odours persist for  a short time during the most intense period of rut. The amount  of androgen rizes sharply and reaches peak concentrations in  late September - early October, decreasing thereafter. The  described behavioural cues occur with a certain constancy in  time in concecutive seasons.  A quantification of the amounts of secretory epithelia in preorbital,  interdigital, caudal and tarsal glands reveals that  only the preorbital gland is subjected to any seasonal and  sexual variation. The apocrine epithelium in this gland is  most developed in mature males during the rutting season and  seems to be dependent upon the presence of an elevated androgen  concentration. The tarsal gland is the least developed  gland while the interdigital and caudal glands are more welldeveloped  and structurally complex. Scattered apocrine glands  are only developed on the legs, the ventral body, oral angle  and in the rump patch. / digitalisering@umu
33

Condições oceanográficas no canal de São Sebastião: fevereiro de 1994 a março de 1995. / Oceanographic conditions in the São Sebastião channel: February 1994 through March 1995.

Silva, Lourval dos Santos 14 December 1995 (has links)
Um conjunto de dados hidrográficos e correntométricos foram coletados entre fevereiro/94 e março/95 no Canal de São Sebastião e região costeira adjacente, para o estudo em primeira aproximação de suas variações sazonais. Da análise da rede externa ao canal observou-se um acentuado contraste de salinidade e de temperatura ao redor da Ilha de São Sebastião, bem como movimentos ascendentes a norte da ISS. Já no interior do canal, ficou determinado que correntes para SW indicam a aproximação da ACAS na costa. Os cruzeiros de verão não apresentaram a formação em duas camadas e no inverno as condições eram de homogeneidade. Indícios de uma recirculação anticiclônica foram observados na entrada sul do canal. As águas superficiais no CSS apresentaram grande susceptibilidade sazonal ao passo que águas profundas têm suas propriedades fortemente reguladas pela maior ou menor aproximação da ACAS. Quase continuidade do transporte de volume foi verificada em dois cruzeiros por praticamente toda a extensão do canal. / A hydrographic and current data set was sampled from February/94 through March/95 in the São Sebastião Channel (SSC) and adjacent coastal region, so as to study in a first approachment its seasonal variations. From the analysis of the hydrographic stations located outside the SSC one observes a strong contrast of salinity and temperature around the São Sebastião Island (SSI), as well as upward movements in the north of the SSI. As to the inner of the channel one realizes that currents to south-west point out to the approach of South Atlantic Central Water SACW) toward the coast. The summer cruises did not exhibit a two-layer character and in the winter there were homogeneous conditions. Signs of an anticyclonic gyre were observed in the southern entrance of the channel. Surface waters in the SSC showed up strong seasonal susceptibility whereas deep waters have its properties influenced by the approach of the SACW. Nearly continuity of the volume transport was observed in two cruises for almost throughout the channel.
34

Análise endócrino-comportamental dos macacos-prego (cebus nigritus) que habitam o Parque Estadual Carlos Botelho / Endocrine and behavioral analysis of capuchin monkeys (Cebus nigritus) inhabiting the Parque Estadual Carlos Botelho

Moreira, Caio Margarido 14 May 2010 (has links)
A resposta ao stress, que inclui a liberação de glucocorticóides (GCs), ajuda animais a lidarem com mudanças ambientais. Espécies selvagens de muitos taxa modulam sazonalmente a liberação de GCs. Segundo a Hipótese Preparatória, a variação sazonal destes hormônios aumenta a eficácia da resposta fisiológica em períodos de maior freqüência de estressores. Hormônios sexuais interagem com GCs e podem modificar a resposta ao stress no contexto reprodutivo. Neste trabalho, nós testamos a Hipótese Preparatória por meio da análise de metabólitos fecais de hormônios e do comportamento de um grupo de macacos-prego (Cebus nigritus) selvagens, e de dados ambientais da região da Mata Atlântica do Parque Estadual Carlos Botelho onde o grupo vive. Nós comparamos os níveis hormonais entre indivíduos, categorias etárias, sexos, ranking, períodos do dia e meses, e com o ambiente físico e social durante o período de agosto de 2007 a julho de 2008. Os principais resultados foram: picos de metabólitos de cortisol (MC) do macho alfa no período de acasalamento e da fêmea adulta grávida durante o final do período de gravidez, acompanhados por níveis elevados de metabólitos de andrógenos e de progesterona, respectivamente. O macho subordinado, jovens e infantes apresentaram um pico de MC durante a baixa disponibilidade de frutos. Estes dados indicam que a reprodução, para adultos, e a disponibilidade de alimentos ricos em energia, para subordinados e imaturos, são fatores importantes para a variação sazonal de glucocorticóides em macacos-prego selvagens da Mata Atlântica / The stress response, including the release of glucocorticoids (GCs), helps animals to cope with environmental changes. Wild species of many taxa seasonally modulate the release of GCs. According to the Preparatory Hypothesis, the seasonal variation of these hormones increases the effectiveness of the physiological response during periods of high frequency of stressors. Sex hormones interact with GCs and can modify the stress response in the reproductive context. In this work we investigate this hypothesis by measuring fecal hormones metabolites and by behavioral observation of a wild blackcapped capuchins monkeys (Cebus nigritus) group living in the Brazilian Atlantic Forest. We analyzed data collected from August 2007 to July 2008. We compared hormones levels among individuals, age-sex classes, rankings, periods of day and seasons, and environmental features and social context. The main results were: peak of cortisol metabolites (CM) of the alpha male during the breeding season, CM peak of the pregnant adult female during the late period of pregnancy, both accompanied by high levels of sexual hormones metabolites (androgens and progesterone, respectively). Subordinate male, juveniles and infants showed a peak of CM during the low fruit availability. These data indicate that the reproduction to adults and the availability of high energetic food to subordinates, juveniles and infants are important factors for the seasonal variation of glucocorticoids of wild capuchin monkeys in the Atlantic Forest
35

Condições oceanográficas no canal de São Sebastião: fevereiro de 1994 a março de 1995. / Oceanographic conditions in the São Sebastião channel: February 1994 through March 1995.

Lourval dos Santos Silva 14 December 1995 (has links)
Um conjunto de dados hidrográficos e correntométricos foram coletados entre fevereiro/94 e março/95 no Canal de São Sebastião e região costeira adjacente, para o estudo em primeira aproximação de suas variações sazonais. Da análise da rede externa ao canal observou-se um acentuado contraste de salinidade e de temperatura ao redor da Ilha de São Sebastião, bem como movimentos ascendentes a norte da ISS. Já no interior do canal, ficou determinado que correntes para SW indicam a aproximação da ACAS na costa. Os cruzeiros de verão não apresentaram a formação em duas camadas e no inverno as condições eram de homogeneidade. Indícios de uma recirculação anticiclônica foram observados na entrada sul do canal. As águas superficiais no CSS apresentaram grande susceptibilidade sazonal ao passo que águas profundas têm suas propriedades fortemente reguladas pela maior ou menor aproximação da ACAS. Quase continuidade do transporte de volume foi verificada em dois cruzeiros por praticamente toda a extensão do canal. / A hydrographic and current data set was sampled from February/94 through March/95 in the São Sebastião Channel (SSC) and adjacent coastal region, so as to study in a first approachment its seasonal variations. From the analysis of the hydrographic stations located outside the SSC one observes a strong contrast of salinity and temperature around the São Sebastião Island (SSI), as well as upward movements in the north of the SSI. As to the inner of the channel one realizes that currents to south-west point out to the approach of South Atlantic Central Water SACW) toward the coast. The summer cruises did not exhibit a two-layer character and in the winter there were homogeneous conditions. Signs of an anticyclonic gyre were observed in the southern entrance of the channel. Surface waters in the SSC showed up strong seasonal susceptibility whereas deep waters have its properties influenced by the approach of the SACW. Nearly continuity of the volume transport was observed in two cruises for almost throughout the channel.
36

A Systems-Level Approach to Understand The Seasonal Factors Of Early Development With Clinical and Pharmacological Applications

Boland, Mary Regina January 2017 (has links)
Major developmental defects occur in 100,000 to 200,000 children born each year in the United States of America. 97% of these defects are from unidentified causes. Many fetal outcomes (e.g., developmental defects), result from interactions between genetic and environmental factors. The lifetime effects from prenatal exposures with low impact (e.g., air pollution) are often understudied. Even when these exposures are studied, the focus is often placed on immediate effects of the exposure (e.g., fetal anomalies, miscarriage rates) leaving lifetime effects largely unexplored. This makes prolonged (or lifetime) effects of low-impact exposures an understudied research area. Included in this set of low-impact exposures is seasonal variance at birth. This thesis measures the effects of seasonal variance at birth on lifetime disease risk at both the population-level and molecular-levels. Four aims, comprising this thesis study, were conducted that utilize data from pharmacology, clinical care (Electronic Health Records) and genetics. These aims included: 1.) Development of an Algorithm to Reveal Diseases with a Prenatal/Perinatal Seasonality Component (described in chapter 2); 2.) Investigation of Climate Variables that Affect Lifetime Disease Risk By Altering Environmental Drivers (described in chapters 3 and 4); 3.) Discovery of Genes Involved in Birth Season – Disease Effects (described in chapter 5) and 4.) Investigation of Pharmacological Inhibitors As Phenocopies of the Birth Season – Disease Effect (described in chapters 6 and 7). Knowledge gained from these four areas, through seven distinct studies, establishes that birth season is a causal risk factor in a number of common diseases including cardiovascular diseases.
37

Análise endócrino-comportamental dos macacos-prego (cebus nigritus) que habitam o Parque Estadual Carlos Botelho / Endocrine and behavioral analysis of capuchin monkeys (Cebus nigritus) inhabiting the Parque Estadual Carlos Botelho

Caio Margarido Moreira 14 May 2010 (has links)
A resposta ao stress, que inclui a liberação de glucocorticóides (GCs), ajuda animais a lidarem com mudanças ambientais. Espécies selvagens de muitos taxa modulam sazonalmente a liberação de GCs. Segundo a Hipótese Preparatória, a variação sazonal destes hormônios aumenta a eficácia da resposta fisiológica em períodos de maior freqüência de estressores. Hormônios sexuais interagem com GCs e podem modificar a resposta ao stress no contexto reprodutivo. Neste trabalho, nós testamos a Hipótese Preparatória por meio da análise de metabólitos fecais de hormônios e do comportamento de um grupo de macacos-prego (Cebus nigritus) selvagens, e de dados ambientais da região da Mata Atlântica do Parque Estadual Carlos Botelho onde o grupo vive. Nós comparamos os níveis hormonais entre indivíduos, categorias etárias, sexos, ranking, períodos do dia e meses, e com o ambiente físico e social durante o período de agosto de 2007 a julho de 2008. Os principais resultados foram: picos de metabólitos de cortisol (MC) do macho alfa no período de acasalamento e da fêmea adulta grávida durante o final do período de gravidez, acompanhados por níveis elevados de metabólitos de andrógenos e de progesterona, respectivamente. O macho subordinado, jovens e infantes apresentaram um pico de MC durante a baixa disponibilidade de frutos. Estes dados indicam que a reprodução, para adultos, e a disponibilidade de alimentos ricos em energia, para subordinados e imaturos, são fatores importantes para a variação sazonal de glucocorticóides em macacos-prego selvagens da Mata Atlântica / The stress response, including the release of glucocorticoids (GCs), helps animals to cope with environmental changes. Wild species of many taxa seasonally modulate the release of GCs. According to the Preparatory Hypothesis, the seasonal variation of these hormones increases the effectiveness of the physiological response during periods of high frequency of stressors. Sex hormones interact with GCs and can modify the stress response in the reproductive context. In this work we investigate this hypothesis by measuring fecal hormones metabolites and by behavioral observation of a wild blackcapped capuchins monkeys (Cebus nigritus) group living in the Brazilian Atlantic Forest. We analyzed data collected from August 2007 to July 2008. We compared hormones levels among individuals, age-sex classes, rankings, periods of day and seasons, and environmental features and social context. The main results were: peak of cortisol metabolites (CM) of the alpha male during the breeding season, CM peak of the pregnant adult female during the late period of pregnancy, both accompanied by high levels of sexual hormones metabolites (androgens and progesterone, respectively). Subordinate male, juveniles and infants showed a peak of CM during the low fruit availability. These data indicate that the reproduction to adults and the availability of high energetic food to subordinates, juveniles and infants are important factors for the seasonal variation of glucocorticoids of wild capuchin monkeys in the Atlantic Forest
38

Análise e interpretação ambiental da química iônica de um testemunho do manto de gelo da Antártica ocidental

Hammes, Daiane Flora January 2011 (has links)
Este estudo utilizou os princípios da glacioquímica para determinar e analisar as variações nas concentrações aniônicas de um testemunho de neve e firn obtido pela perfuração no manto de gelo da antártica ocidental no verão austral de 2004/05. O testemunho IC-6 (81°03'S, 79°51'W), de 34,65 m de profundidade, obtido a 750 m de altitude, foi subamostrado em sala limpa (CLASE 100), usando um sistema de derretimento contínuo desenvolvido pela equipe do Climate Change Institute (CCI) da Universidade do Maine (EUA). Esse processo gerou 1.368 amostras para análises por cromatografia iônica, cerca de 58 amostras por metro, permitindo detalhamento sazonal da variabilidade das concentrações dos íons majoritários. O testemunho representa 66 ± 3 anos de dados ambientais, segundo a datação baseada na variação sazonal dos íons Cl-, Na+, Mg+2 e SO4-2. O testemunho de 23,61 m em equivalente d’água, corrigido para variações em densidade, representa uma acumulação liquida média anual de 0,36 m (em equivalente d’água). Assim, a camada ao fundo foi formada no ano de 1938 (± 3 anos). As concentrações iônicas médias medidas no IC-6, são: [(Na+= 66,92 ± 2,32 μg L-1), (K+= 3,31 ± 0,18 μg L-1); (Mg+2= 10,07 ± 0,25 μg L-1); (Ca+2 = 16,93 ± 0,38 μg L-1); (Cl- = 155,74 ± 4,40 μg L-1); (NO3- = 56,01 ± 0,80 μg L-1); (SO4 2 = 55,65 ± 1,36 μg L-1); e (CH3SO3 (MS) = 14,11 ± 1,19 μg L-1)]. As maiores concentrações de Na+, Cl-, e Mg+2 foram interpretadas como picos de invernos, associadas diretamente ao aerossol dos mares circundantes em respostas, provavelmente, a advecção mais intensa de massas de ar (marinho) sobre as plataformas de gelo, e portanto são também traçadores marinhos. Já o perfil (série) de sulfato está em antifase, em relação às variações nas espécies Na+, Cl- e Mg+2. De origem predominantemente marinha, o sulfato total apresentou maiores concentrações durante a primavera e verão (períodos de maior atividade biológica nos mares circumpolares), possivelmente marcando a variação sazonal da atividade biológica na região. Embora em alguns intervalos essa ―antifase‖ não fique tão clara, é o que ocorre na maior parte do testemunho IC-6, condição que auxiliou na interpretação da variação sazonal observada principalmente na série do cloro. O perfil de excesso de sulfato apresenta perfil similar ao de sulfatos total, com picos concomitantes. Além da forte correlação com o íon SO4-2, também é observada uma correlação fraca a moderada com o íon nitrato. Picos concomitantes deste íon com o excesso de sulfato representam eventos episódicos como é o caso das erupções vulcânicas de grande magnitude. A variabilidade da concentração de nitrato não esta associada ao aerossol marinho, como aponta a falta de correlação entre esse ânion e o Cl-, Na+ e Mg2+. Porém, série de nitrato apresenta muitos períodos bem marcados e correlacionados com as concentrações de excesso de sulfato, devendo representar a ocorrência de eventos episódicos, como erupções vulcânicas. Entretanto, a análise de íons maiores nesse estudo não possibilitou a identificação de eventos específicos, será necessário o uso de técnicas complementares para determinação de elementos traços. Sugere-se que o nitrato seria transportado e depositado por massas de ar provenientes da estratosfera ou da alta troposfera e que grandes concentrações dessa espécie poderiam estar associadas ao registro de ocorrências de eventos vulcânicos. Essa característica parece ser coerente com os picos correlacionáveis nos perfis (séries) de nitrato e sulfatos. Além da variação sazonal (observada principalmente no perfil de cloro), foram identificados outros padrões recorrentes no tempo (ciclos), principalmente nas séries de dos íons Na+, Cl- e Mg2+ (origem marinha) e NO3-. O principal ciclo identificado, de aproximadamente 17,3 anos, necessita melhor investigação. A secundária, em torno de 10 anos, estaria associada ao ciclo solar (de 10,7 anos). Também são observados ciclos com períodos entre 2 a 5 anos, que poderiam estar associados ao fenômeno ENOS (El Niño - Oscilação Sul). Ao comparar as concentrações médias do IC-6 com de outros sítios no interior da Antártica, observa-se uma abrupta redução ao atravessar as montanhas Transantárticas em direção ao Polo Sul geográfico. Sugere-se que cordilheira esteja barrando o transporte dos aerossóis marinhos para o interior do continente devido a um efeito orográfico sobre a precipitação. / This study employed glaciochemical principles to determine and analyze the variation of anionic concentrations of a firn and snow core obtained from the Western Antarctic Ice Sheet, in the summer of 2004/05. The IC-6 core (81°03'S, 79°51'W), reaching 34.65 m in depth, was extracted at 750 m above sea level. This core was subsampled in a Class 100 clean room, employing a discrete continuous melting system developed by the team at the Climate Change Institute (CCI), University of Maine, USA. This process produced 1,368 samples for ionic chromatographic analyses, approximately 58 samples per meter, permitting a seasonal-scale resolution of the main ion concentrations and variabilities. This core represents 66 ± 3 years of environmental data, according to Cl-, Na+, Mg+2 e SO4-2 ion seasonal variations. The 23.61 m core, in water equivalent, corrected for the density variation, represents an annual net accumulation average rate of 0.36. The deepest layer was deposited in 1938 (± 3 ). Core mean ionic concentrations are: [(Na+= 66,92 ± 2,32 μg L-1); (K+= 3,31 ± 0,18 μg L-1); (Mg+2= 10,07 ± 0,25 μg L-1); (Ca+2 = 16,93 ± 0,38 μg L-1); (Cl- = 155,74 ± 4,40 μg L-1); (NO3- = 56,01 ± 0,80 μg L-1); (SO4 2 = 55,65 ± 1,36 μg L-1); and (CH3SO3 (MS) = 14,11 ± 1,19 μg L-1)]. The largest concentrations of Na+, Cl-, e Mg+2 were interpreted as winter peaks, directly associated with the aerosols from the surrounding seas, probably, in response to the intensification of marine air mass advection on the ice shelves, and, thus, also being marine tracers. The sulphate profile (series) presents an antiphase, with relation to Na+, Cl- e Mg+2 species variations. Predominantly of marine origin, total sulphates presented greater concentrations during Spring and Summer (periods of greater biologic activity in the Southern Ocean), possibly marking the seasonal variation of biologic activity in the region. Although in some intervals of this ―antiphase‖ are not clearly evident, they are consistent throughout most of the IC-6 core, assisting with the interpretation of the observed seasonal variations, particularly when related to chlorine data series. The sulphate excess profile is similar to total sulphate profile, showing concomitant spikes. Besides the strong correlation to tSO4-2 ion, a weak to moderate correlation was observed for nitrate ions. Coinciding peaks for this ion with excess sulphate may represent episodic events, such as presented by volcanic events of great magnitude. The nitrate concentration variability is not associated to marine aerosols, as shown by the lack of correlation between this anion and Cl-, Na+ e Mg2+. The nitrate series presents many well marked periods and seem to be correlated to excess sulphate concentrations, possibly representing the occurrence of episodic events, such as volcanic eruptions. Even so, the major ions analyses proposed by this work did not make the identification of such episodic events clear. Such events need to be addressed with complementary techniques to determine the specific trace elements. These results suggest that nitrate is transported and deposited by stratospheric or high tropospheric air masses, and that great concentrations of this species could be associated to the recorded volcanic events. This characteristic appears to be coherent with the spikes in the nitrate and sulphate profiles. Besides the seasonal variation (observed, principally, in the chlorine profile), other time cycle/patterns were identified, mainly those related to Na+, Cl- e Mg2+ ion series (of marine origin) and NO3-. The main identified cycle, approximately 17.3 years, ensues to be better investigated. A second cycle, presenting a 10 year period, is possibly associated to the solar cycle (10.7 years). Shorter cycles of 2 and 5 year periods could possibly be related to the ENSO phenomenon. On comparing average concentrations of the IC-6 core with other sites, farther within the Antarctic continent, an abrupt reduction was observed, from the Trans-Antarctic mountains to the Geographic South Pole, suggesting that this mountain range could be a barrier for marine aerosol transport to the interior of the continent, due to an orographic effect on the precipitation.
39

Seasonal cycle of gonadal steroidogenesis and the effects of luteinizing hormone and luteinizing hormone releasing hormone on thein vitro and in vivo steroidal secretions in monopterus albus

Chen, Hui, 陳慧 January 1989 (has links)
published_or_final_version / Zoology / Master / Master of Philosophy
40

Multivariate time series modelling.

Vayej, Suhayl Muhammed. January 2012 (has links)
This research is based on a detailed description of model building for multivariate time series models. Under the assumption of stationarity, identification, estimation of the parameters and diagnostic checking for the Vector Auto regressive (p) (VAR(p)), Vector Moving Average (q) (VMA(q)) and Vector Auto regressive Moving Average (VARMA(p, q) ) models are described in detail. With reference to the non-stationary case, the concept of cointegration is explained. Procedures for testing for cointegration, determining the cointegrating rank and estimation of the cointegrated model in the VAR(p) and VARMA(p, q) cases are discussed. The utility of multivariate time series models in the field of economics is discussed and its use is demonstrated by analysing quarterly South African inflation and wage data from April 1996 to December 2008. A review of the literature shows that multivariate time series analysis allows the researcher to: (i) understand phenomenon which occur regularly over a period of time (ii) determine interdependencies between series (iii) establish causal relationships between series and (iv) forecast future variables in a time series based on current and past values of that variable. South African wage and inflation data was analysed using SAS version 9.2. Stationary VAR and VARMA models were run. The model with the best fit was the VAR model as the forecasts were reliable, and the small values of the Portmanteau statistic indicated that the model had a good fit. The VARMA models by contrast, had large values of the Portmanteau statistic as well as unreliable forecasts and thus were found not to fit the data well. There is therefore good evidence to suggest that wage increases occur independently of inflation, and while inflation can be predicted from its past values, it is dependent on wages. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2012.

Page generated in 0.1307 seconds