Business Cycle Theory and Econometrics

We outline in turn criticisms made by econometricians of the methods used in empirical business-cycle research and then criticisms made by business-cycle researchers of some methods used by econometricians. The aim is to clarify and in some cases correct these criticisms. Overall there is no conflict in using rigourous statistical procedures to study modern dynamic stochastic general equilibrium models. We also provide a concise bibliography of recent research on statistical methods for business-cycle models.business cycles, time-series econometrics

Empirical Likelihood Block Bootstrapping

Monte Carlo evidence has made it clear that asymptotic tests based on generalized method of moments (GMM) estimation have disappointing size. The problem is exacerbated when the moment conditions are serially correlated. Several block bootstrap techniques have been proposed to correct the problem, including Hall and Horowitz (1996) and Inoue and Shintani (2006). We propose an empirical likelihood block bootstrap procedure to improve inference where models are characterized by nonlinear moment conditions that are serially correlated of possibly infinite order. Combining the ideas of Kitamura (1997) and Brown and Newey (2002), the parameters of a model are initially estimated by GMM which are then used to compute the empirical likelihood probability weights of the blocks of moment conditions. The probability weights serve as the multinomial distribution used in resampling. The first-order asymptotic validity of the proposed procedure is proven, and a series of Monte Carlo experiments show it may improve test sizes over conventional block bootstrapping.Econometric and statistical methods

Empirical Likelihood Block Bootstrapping

Monte Carlo evidence has made it clear that asymptotic tests based on generalized method of moments (GMM) estimation have disappointing size. The problem is exacerbated when the moment conditions are serially correlated. Several block bootstrap techniques have been proposed to correct the problem, including Hall and Horowitz (1996) and Inoue and Shintani (2006). We propose an empirical likelihood block bootstrap procedure to improve inference where models are characterized by nonlinear moment conditions that are serially correlated of possibly infinite order. Combining the ideas of Kitamura (1997) and Brown and Newey (2002), the parameters of a model are initially estimated by GMM which are then used to compute the empirical likelihood probability weights of the blocks of moment conditions. The probability weights serve as the multinomial distribution used in resampling. The first-order asymptotic validity of the proposed procedure is proven, and a series of Monte Carlo experiments show it may improve test sizes over conventional block bootstrapping.generalized methods of moments, empirical likelihood, block bootstrap

Integrity of the circadian time-keeping system in chronic fatigue syndrome

Chronic Fatigue Syndrome (CFS) is a debilitating condition in which severe, ongoing fatigue is the most prominent of a complex of somatic, psychological and neuropsychological symptoms. The aetiology of CFS remains uncertain and, to date, efforts to distinguish a clear pathophysiological profile for the disorder have been unsuccessful. Current evidence suggests that, rather than being a discrete disease entity with a single cause, CFS is a clinical condition resulting from the interaction of a number of pathophysiological factors, including acute infections, stress and psychiatric disorder. Recently, there has been some interest in the proposition that disordered circadian time-keeping may contribute to the development and/or course of the illness. The rationale for the investigation of circadian factors in CFS is based on the fact that disorders known to be associated with circadian dysregulation, such as jet lag and shiftwork related syndromes have a high degree of symptomatological overlap with CFS. Also, the presence of circadian disturbance could account, in part, for other phenomenological aspects of CFS, including the high rates of comorbid affective disturbance, and the reports of low-level immune dyregulation among sufferers. While several recent studies have produced some evidence of chronobiological dysregulation in CFS patients, much work remains before conclusions can be drawn about the presence, nature and clinical significance of circadian disturbance in CFS. This thesis describes a series of studies that were designed to systematically investigate: 1. whether CFS is associated with a state of circadian dysregulation, and 2. whether circadian dysregulation contributes significantly to the symptomatology of CFS. The first of the 5 studies reported here compared the circadian patterns of sleep-activity of CFS sufferers with those of healthy controls. Results indicated that CFS patients\u27 sleep-activity cycles were significantly phase delayed compared to controls, and that some aspects of their circadian profiles of sleep-activity were related to some measures of sleep-disturbance and well-being. Studies 2 and 3 investigated the relationship between rhythms of sleep-wake and core temperature in CFS patients and healthy controls. The major finding from these studies was that sleep-wake and core temperature rhythms appear to be less effectively synchronised. Further evidence was collected that suggested that there was a relationship between circadian parameters and symptom measures in the CFS group. While this indicated that circadian dysregulation is linked in some way to the symptoms of CFS, assessment of the actual clinical significance of circadian disturbances required the use of a prospective methodology. The final two studies, therefore, report on a placebo-controlled trial of clinical interventions that were designed to restore circadian integrity to CFS patients, in order to see whether this would lead to a reduction in symptom number or severity. Results indicated that, although patients experienced improvements across a range of measures of symptoms and functional capacity, these were small in magnitude, of unlikely clinical significance, and no greater, in general, to improvements reported by patients who underwent placebo treatment. These results, along with those of the earlier studies, are discussed with respect to their implications regarding the presence and significance of circadian dysregulation. It is concluded that, while they provide evidence that CFS is associated with a degree of both internal and external circadian desynchrony, these findings suggest that circadian dysregulation is likely to be only a peripheral, contributor to the processes that generate and maintain the symptom complex. These findings are discussed with respect to how they contribute to our overall understanding of this multi-dimensional condition, and the implications they have for the continuing effort to investigate the causes and treatment of CFS

Determination of rainfall/runoff model parameters

University of Technology Sydney. Faculty of Engineering.Runoff estimates both peaks and volumes are called for in design analysis for the sizing of a wide range of engineering structures. In many instances runoff records are very short or not available and it is necessary to use synthetic rainfall data and apply a rainfall/runoff model to estimate appropriate design hydrographs. This thesis addresses the particular portion of the rainfall/runoff process conversion dealing with the development of excess hyetographs prior to catchment routing and the estimation of the parameters affecting such development. Details are given on field based parameter estimating procedures as well as further model development to better reflect measurable input parameters. A joint probability model linking moisture deficiency criteria prior to an event, rainfall data and measured catchment parameters is developed and applied on Canberra data

In mom and dad\u27s shadows: An exploration of family of origin influence on parenting styles

This thesis studies the influence that family of origin upbringing has on current parenting practice. Eight adult children were interviewed, and their experience, past and present, is interpreted within the literature review frame of two broad parent-child interactions: emotional support and parental control. Interviewees\u27 current parenting behaviors are also examined within the literature review discussion on continuity of behavioral patterns between generations. Research findings are then discussed within a theological and pastoral focus on differentiation in family

Utilization of near-isogenic lines to identify genes underlying iron-efficiency QTL

Nutrient deficiencies are a significant abiotic stress of soybean. Iron deficiency chlorosis is a major concern in the upper midwestern region of the United States due to the prevalence of calcareous soils. Soybean\u27s susceptibility to iron stress results in yield losses into the hundreds of millions each year. Understanding the molecular differences between resistant and susceptible cultivars will significantly affect future yield and revenue. Through the use of near-isogenic lines (NILs), molecular markers, and gene expression we have identified the donor parent introgressions through both classical SSR mapping and a novel method of SNP clustering which can be preformed using data generated through either chip-based SNP genotyping platforms or identified de novo though re-sequencing techniques. By aligning the newly constructed introgression map with the previously identified Fe efficiency QTL we identified a region on chromosome 3 where the two were positionally coincident. To further narrow this region of interest, the NIL was backcrossed an additional generation to the recurrent parent in order to identify recombinations within the chromosome 3 introgression. These lines were identified as Sub-NILs. Recombinants were identified in regular intervals throughout the introgression and phenotyped. Donor parent alleles identified within a 250 kb region represented the minimum interval differentiating the efficient and inefficient Sub-NILs. A second NIL sharing the same donor parent was screened for introgressions. The only region of the genome the two NILs shared alleles from the donor parent, introgressions, were localized to the same region on chromosome 3 further adding support to the importance of the these alleles. Eighteen genes were annotated within the region and were screened for gene expression differences in soybean roots 24 hours following the removal of iron in the growth medium. Two of the genes were differentially expressed between sufficient and insufficient iron conditions. Interestingly, these genes are homologs of two transcription factors in Arabidopsis thaliana known to function in the iron response pathway. Sanger sequencing of these two genes identified a significant mutation that deletes 4 amino acids in the susceptible lines. We hypothesize that this deletion disrupts the FIT / bHLH heterodimer that has been shown to induce known iron acquisition genes