Long-Run Causal Order: A Preliminary Investigation

The relation between causal structure and cointegration and long-run weak exogeneity is explored using some ideas drawn from the literature on graphical causal modeling. It is assumed that the fundamental source of trending behavior is transmitted from exogenous (and typically latent) trending variables to a set of causally ordered variables that would not themselves display nonstationary behavior if the nonstationary exogenous causes were absent. The possibility of inferring the long-run causal structure among a set of time-series variables from an exhaustive examination of weak exogeneity in irreducibly cointegrated subsets of variables is explored and illustrated.

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Time Series Modelling of The Volume of Overland Timber Export in The Bolgatanga Municipality

Journal of Scientific Research and Reports ◽

10.9734/jsrr/2020/v26i430253 ◽

2020 ◽

pp. 124-138

Author(s):

Henry M. Kpamma ◽

Silverius K. Bruku ◽

John A. Awaab

Keyword(s):

Time Series ◽

Moving Average ◽

Preliminary Investigation ◽

Arima Model ◽

Estimation Method ◽

Long Run ◽

Time Series Modelling ◽

The Future ◽

Equilibrium Relationships ◽

The Right

Aims/ Objectives: This research was carried out with the intention of using time series to model the volume of overland timber exported within Bolgatanga municipalityPlace and Duration of Study: Study of the time series was based on a historical data of the volume of timber exported for twenty consecutive years, from 1999 to 2019 within Bolgatanga municipality.Methodology: The three-stage iterative modeling approach for Box Jenkins was used to match an ARIMA model and to forecast both the amount of timber export and the confiscated lumber. ARIMA method incorporates a cycle of autoregressive and a moving average. The three-stage iterative modeling technique of Box Jenkins which were used are model recognition, parameter estimation and/or diagnostic checks were also made. Results: From the preliminary investigation, the study showed that the amount of timber exported in municipality is skewed to the right, suggesting that much of the amount of timber exported is below the average. This, together with the high volatility in the volume of timber exported, indicates that the amount of timber exported within the municipalities during the twenty-year period was low. The plots from the trends also showed robust variations in the volume of timber exported indicating that timber exporters do not have better grips with the concepts and applications of export technology, hence the erratic nature of the volume of timber exported over the period. The quadratic pattern and the ARIMA (1,1,1) model best represented the amount of timber exported.The analysis further indicated that there will be a further decrease in the amount of timber export from the five years projection into the future. Over the last two decades the Bayesian approach to VAR has gained ground. For a future report, this estimation method will be followed to examine the ”long-run equilibrium relationships” between timber export volumes and climate change.Conclusion: The quadratic pattern and the ARIMA (1,1,1) model best represented the amount of timber exported. There will be a further decrease in the amount of timber export from the five years projection into the future.

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Surface ultrastructure of danazol treated rat endometrium: A SEM study

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010007641x ◽

1983 ◽

Vol 41 ◽

pp. 556-557

Author(s):

R.P. Apkarian ◽

J.S. Sanfilippo

Keyword(s):

Cross Sections ◽

Reproductive Tract ◽

Preliminary Investigation ◽

Breast Disease ◽

Distal Segment ◽

Uterine Horn ◽

Female Reproductive Tract ◽

Ultrastructural Changes ◽

Cycle Phase ◽

Sprague Dawley

The synthetic androgen danazol, is an isoxazol derivative of ethisterone. It is utilized in the treatment of endometriosis, fibrocystic breast disease, and has a potential use as a contraceptive. A study was designed to evaluate the ultrastructural changes associated with danazol therapy in a rat model. The preliminary investigation of the distal segment of the rat uterine horn was undertaken as part of a larger study intended to elucidate the effects of danazol on the female reproductive tract.Cross-sections (2-3 mm in length) of the distal segment of the uterine horn from sixteen Sprague-Dawley rats were prepared for SEM. Ten rats in estrus served as controls and six danazol treated rats were noted to have alterations of the estrus cycle i.e. a lag in cycle phase or noncycling patterns. Specimens were fixed in 3% glutaraldehyde in 0.05M phosphate buffer containing CaCl2 at pH 7.0-7.4 and chilled to 4°C. After a brief wash in distilled water, specimens were passed through a graded series of ethanol, critical point dryed in CO2 from absolute ethanol, and coated with 6nm Au. Observations were made with an IS1-40 SEM operated at 15kV.

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A Comparison of the Ultrastructural Morphology of Hepatic Necrosis in BDF1 Mice

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100099350 ◽

1981 ◽

Vol 39 ◽

pp. 586-587

Author(s):

Becky Jackson

Keyword(s):

Endoplasmic Reticulum ◽

Smooth Endoplasmic Reticulum ◽

Preliminary Investigation ◽

Hepatic Necrosis ◽

Hepatic Tissue ◽

Pronounced Increase ◽

Glycogen Store ◽

Ultrastructural Morphology ◽

Mitochondrial Integrity ◽

Glycogen Stores

Preliminary investigation has indicated similarity in hepatic ultrastructural morphology in nutritional deprivation, and cyanide induced hepatic necrosis. Analysis of hepatic tissue has indicated disruption of intracellular membranes, specifically, reduction in rough endoplasmic reticulum (RER) mitochondrial integrity, and glycogen stores. An increase in smooth endoplasmic reticulum (SER) portion was observed.To further investigate the apparent equivalence of necrotic morphology, ultrastructura1ly, BDF1 mice were subjected to senescence, nutritional deprevation, potassium cyanide (KCN) induced toxemia, and acetaminophen induced toxemia. Controls were utilized to ellucidate non-necrotic hepatocellular normals. U1trastructura1 investigation of controls (Fig. 1) shows densely granular RER, abundant glycogen stores, and morphologically normal mitochondria. Subjects with acetaminophen induced necrosis exhibit reduced normal RER with increased levels of dialated, vesicular RER in apparent conversion to SER (Fig. 2), loss of mitochondrial integrity, and glycogen store reduction. Senescent subjects exhibit a pronounced increase in SER and loss of glycogen store. (Fig. 3). Investigation of the senescent SER at high magnification (Fig. 5) indicates that the SER is arising from degranulating and vesiculating RER.

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Ultrastructural Effects of Acute Kepone Treatment in Rats

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010009141x ◽

1976 ◽

Vol 34 ◽

pp. 286-287

Author(s):

Richard L. Klein ◽

Åsa K. Thureson-Klein ◽

Harihara M. Mehendale

Keyword(s):

Neurological Disorders ◽

Corn Oil ◽

Preliminary Investigation ◽

Reproductive Capacity ◽

Ultrastructural Changes ◽

Lipid Deposition ◽

Severe Toxicity ◽

Sprague Dawley ◽

Ether Anesthesia ◽

Sprague Dawley Rats

KeponeR (decachlorooctahydro-1,3,4-metheno-2H-cyclobuta[cd]pentalen-2-one) is an insecticide effective against ants and roaches. It can cause severe toxicity in fishes, birds, rodents and man. Prominent effects include hepatic lipid deposition and hypertrophy, impairment of reproductive capacity and neurological disorders. Mitochondrial oligomycin-sensitive Mg2+-ATPase is also inhibited. The present study is a preliminary investigation of tissue ultrastructural changes accompanying physiological signs of acute toxicity, which after two days treatment include: pronounced hypersensitivity and tremor, various degrees of anorexia and adipsia, and decreased weight gain.Three different series of adult male Sprague-Dawley rats (Charles River or CD-I) were treated by intubation with Kepone in corn oil at a dose of 50 mg per kg for 3 successive days or at 200 ppm in food for 8 days. After ether anesthesia, rats were immediately perfused via a cannula in the left ventricle with 4% p-formaldehyde and 0.5% glutaraldehyde in Millonig's phosphate buffer at pH 7.2 for 20-30 min at 22°C.

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