Statistical Signal Extraction and Filtering: Notes for the Ercim Tutorial, December 9th 2010

These notes have been written to accompany a tutorial session held at the London School of Economics as a prelude to the ERCIM conference of December 2010.

The Discrete–Continuous Correspondence for Frequency-Limited Arma Models and the Hazards of Oversampling

Discrete-time ARMA processes can be placed in a one-to-one correspondence with a set of continuous-time processes that are bounded in frequency by the Nyquist value of ? radians per sample period. It is well known that, if data are sampled from a continuous process of which the maximum frequency exceeds the Nyquist value, then there will be a problem of aliasing. However, if the sampling is too rapid, then other problems will arise that will cause the ARMA estimates to be severely biased. The paper reveals the nature of these problems and it shows how they may be overcome. It is argued that the estimation of macroeconomic processes may be compromised by a failure to take account of their limits in frequency.Stochastic Differential Equations; Band-Limited Stochastic Processes; Oversampling

Alternative Methods of Seasonal Adjustment

Alternative methods for the seasonal adjustment of economic data are described that operate in the time domain and in the frequency domain. The time-domain method, which employs a classical comb filter, mimics the effects of the model-based procedures of the SEATS–TRAMO and STAMP programs. The frequency-domain method eliminates the sinusoidal elements of which, in the judgment of the user, the seasonal component is composed. It is proposed that, in some circumstances, seasonal adjustment is best achieved by eliminating all elements in excess of the frequency that marks the upper limit of the trend-cycle component of the data. It is argued that the choice of the method seasonal adjustment is liable to affect the determination of the turning points of the business cycle.Wiener–Kolmogorov Filtering; Frequency-Domain Methods; The Trend-Cycle Component

Mining Sequences of Developer Interactions in Visual Studio for Usage Smells

In this paper, we present a semi-automatic approach for mining a large-scale dataset of IDE interactions to extract usage smells, i.e., inefficient IDE usage patterns exhibited by developers in the field. The approach outlined in this paper first mines frequent IDE usage patterns, filtered via a set of thresholds and by the authors, that are subsequently supported (or disputed) using a developer survey, in order to form usage smells. In contrast with conventional mining of IDE usage data, our approach identifies time-ordered sequences of developer actions that are exhibited by many developers in the field. This pattern mining workflow is resilient to the ample noise present in IDE datasets due to the mix of actions and events that these datasets typically contain. We identify usage patterns and smells that contribute to the understanding of the usability of Visual Studio for debugging, code search, and active file navigation, and, more broadly, to the understanding of developer behavior during these software development activities. Among our findings is the discovery that developers are reluctant to use conditional breakpoints when debugging, due to perceived IDE performance problems as well as due to the lack of error checking in specifying the conditional

Constitutional Law - Landlord-Tenant Law - Due Process - Tenant\u27s Due Process Right to Notice and an Opportunity to Be Heard Prior to Distraint of Tenant\u27s Property

The United States District Court for the Eastern District of Pennsylvania has held Pennsylvania\u27s statutory distraint procedure facially unconstitutional in violation of the due process clause of the fourteenth amendment, since the procedure permitted a landlord, acting upon his unilateral claim that rent is owing, to levy on property found on a tenant\u27s premises while only requiring the landlord to give his tenant notice within five days following the distraint. Gross v. Fox, 349 F. Supp. 1164 (E.D. Pa. 1972)

Infection frequently triggers thrombotic microangiopathy in patients with preexisting risk factors : a single-institution experience

Thrombotic microangiopathies are rare conditions characterized by microangiopathic hemolytic anemia, microthrombi, and multiorgan insult. The disorders, which include hemolytic uremic syndrome and thrombotic thrombocytopenic purpura, are often acute and life threatening. We report a retrospective analysis of 65 patients presenting to our institution from 1997 to 2008 with all forms of thrombotic microangiopathy. Therapeutic plasma exchange was a requirement for analysis and 65 patients were referred to our institution; 66% of patients were female and median age at presentation was 52 years. Bacterial infection was the most commonly identified etiologic factor and in the multivariate model was the only significant variable associated with survival outcome (odds ratio 5.1, 95% confidence interval, 1.2-21.7). As infection can be considered a common trigger event for thrombotic microangiopathy, patients with hepatobiliary sepsis may benefit from elective cholecystectomy. We conclude that bacterial infection frequently triggers TTP and other thrombotic microangiopathies in patients with preexisting risk factors and propose a model for the development of these syndromes

DETERMINATION OF LARVAL FISH SURVIVAL FROM FEEDING AND DISTRIBUTION OBSERVATIONS

The series of papers round which this thesis is based highlight the inherent problems in assessing larval fish feeding success from sampling programmes and gut contents analysis, and show through novel observations, that counting the number of food items in the gut is not necessarily a good indication of feeding success. Food type, digestibility and size, gut passage rates and the particular lipid classes the food contains, must all be considered, illustrating the difficulties in interpreting larval fish energetics from field studies. The resistance to digestion demonstrated for copeped eggs, means that a potentially rich source of energy cannot be utilised. This may have severe nutritional consequences for the early larvae of many important commercial fish species which can feed heavily on these eggs, possibly influencing ultimate recruitment levels. While much can be learned from coarse grid, depth integrated plankton sampling, interpretation of relationships between food availability and larval condition was shown to require precise sampling of the larvae in their actual feeding environment. Intense integrated and vertically stratified plankton sampling allowed the most detailed observations on food selection by fish larvae ever carried out and demonstrated their considerable foraging adaptability, even in a changing food environment. Food availability is undoubtedly an important factor in larval fish survival because of its affect on condition and growth rates, but many other factors are now known to be involved and it is accepted that recruitment in a species may be decided at almost any stage of early development. The traditional approach to understanding the environmental impact on larval survival and fish recruitment has been by observational field ecology and correlation techniques. However, more recently, advances in mathematical modelling techniques in which we are involved, are allowing the representation and simulation of both physical and biological oceanographic processes. Progress in understanding how selective forces generally shape recruitment will depend increasingly on these exciting new techniques

Angiotensin II is Required to Induce Exaggerated Salt Sensitivity in Dahl Rats Exposed to Maternal Separation

We previously reported that maternal separation, rat model of early life stress, enhances pressor responses to acute and chronic stressors. The aims of this study were to determine whether Dahl salt-sensitive (DS) rats subjected to maternal separation (MatSep-DS) as compared to normally reared DS (Ctl-DS) rats show exaggerated blood pressure responses to acute behavioral stressors, such as restraint stress or air jet stress (AJS), or, hypertensive stimuli including chronic high-salt diet (4% NaCl) and angiotensin II (AngII) infusion (200 ng/Kg/min) during 1 week. MatSep was performed in male DS rats for 3 h/day from postnatal days 2-14. At 8 weeks of age, rats were implanted with telemetry transmitters and allowed to recover. Mean arterial pressure (MAP) was not different between MatSep-DS and Ctl-DS rats at baseline (120 ± 2 mmHg vs. 118 ± 1 mmHg, n = 4-8). Blood pressure responses during AJS and restraint stress were not different between MatSep-DS and Ctl-DS at 3 min. However, blood pressure recovery from AJS was significantly impaired in MatSep-DS rats compared to Ctl-DS rats (P \u3c 0.05). 3-h stress-induced similar responses in MatSep and Ctl-DS rats. Chronic blood pressure responses to AngII infusion in rats fed a high-salt diet displayed enhanced MAP in MatSep-DS when compared with Ctl-DS rats (167 ± 5 mmHg vs. 152 ± 2 mmHg, pinteraction \u3c0.05). However, MAP increased similarly in both groups in response to AngII infusion or high-salt diet separately. Renal parameters such as proteinuria, urine flow rate, and urine electrolytes were not different between groups in response to each treatment. In summary, salt sensitivity induces exaggerated blood pressor responses only in presence of AngII due to early life stress