Oaxaca/Blinder decompositions for nonlinear models

This paper describes the estimation of a general Blinder–Oaxaca decomposition of the mean outcome differential of linear and nonlinear regression models. Departing from this general model, we show how it can be applied to different models with discrete and limited dependent variables.

Evaluation of neurographic parameters in diabetic neuropathy

Diabetic neuropathy is a frequent complication of patients suffering from diabetes mellitus (either type I or type II diabetes). The clinical picture of this disease varies widely from non-symptomatic courses to severe disabling and potential life-threatening cases, mostly due to autonomic neuropathy. The treatment of diabetic neuropathy is despite huge investments in clinical research mostly related to an effective control of blood glucose levels. Beside acute courses of diabetic neuropathy, which tend to remit, most patients suffer from chronic courses of diabetic neuropathy, where distal symmetric neuropathy is the most common course of disease. These cases are usually chronic progressive, therefore early diagnosis and intervention is mandatory. The advantages of neurographic testing as diagnostic tool in terms of reliability, validity, relevance, and patient’s safety is well accepted. Used by medical professionals this method provides information about the functional status of the peripheral nervous system. This study was conducted comparing normal subjects and patients with diabetes mellitus or impaired glucose tolerance, who with suspicion of diabetic neuropathy. The aim of this study was to identify additional neurographic markers who can differentiate between the two patient groups in order to possibly provide a diagnostic tool for the early di-agnosis of diabetic neuropathy. These markers should supplement the markers already es-tablished so as maximum nerve conduction velocity or amplitude of the compound muscle action potential. The evaluation of further markers so as further conduction velocities, posi-tive/negative amplitudes, quotients of intervals/amplitudes/areas revealed significant differ-ences between the two patient groups, nevertheless also the standard markers demon-strated significant differences. These findings could be related to the fact, that the average age in group 2 with diabetic patients was substantially higher than in group 1 with normal subjects. In addition the progression of diabetic neuropathy could be more advanced, so that an additional study with patients in an earlier stage of disease and comparable age could im-prove the diagnosis of early diabetic neuropathy

PanelWhiz - Efficient Data Extraction of Complex Panel Data Sets: An Example Using the German SOEP

This paper outlines a panel data retrieval program written for Stata/SE 10 or better, which allows easier accessing of complex panel data sets. Using a drop-down menu and mouse click system, the researcher selects variables from any and all available years of a panel study. The data is automatically retrieved and merged to form a "long file", which can be directly used by the Stata panel estimators. The system implements modular data cleaning programs called "plugins". Yearly updates to the data retrievals can be made automatically. Projects can be stored in libraries allowing modular administration and appending. The paper exemplifies the power of PanelWhiz using the example of the German SOEP (German Socio-Economic Panel Study).Panel data, storage, retrieval

PanelWhiz plugins: automatic vector-oriented data cleaning for large scale panel datasets

PanelWhiz plugins are modular data-cleaning programs for specific items in PanelWhiz. Each plugin is designed to recode, deflate, and change existing variables being extracted in a panel-data retrieval. Furthermore, new variables can be generated on the fly. The PanelWhiz plugin system is a macro language that uses new-style dialog boxes and Stata’s modularized class system, allowing a vector orientation for data cleaning. The PanelWhiz plugins can even be generated using a PanelWhiz plugin front-end, allowing users to create plugins but not have to write Stata code themselves. The system is set up to allow data cleaning of any PanelWhiz-supported dataset.

Optimal large package administration for Stata

Stata is quite simple to use for smaller ado-packages stored on user web pages. However, when the number of files in a package becomes large and the files need to be updated regularly, this task becomes cumbersome. Package updates could take a long time to complete. Here a method of storing packages as compressed archives on the host server is outlined, whereby the user sends a query to the update server to check for a new version. If a new version is available, the package archive is downloaded in its entirety and is then extracted and installed locally. This approach is far more efficient with respect to installation times (typically only 1/10 of the time needed) than downloading many text files individually. For large packages, the bottleneck is most often the download time. Currently this automated updating can be achieved with a Stata ado-file and the aid of additional binaries (such as tar, gzip, and zip). The usability of this technique would be enhanced dramatically if the functionality of an archiving format (such as tar, gzip, zip) were directly integrated into the Stata binary. Even encrpyted files could be distributed in this manner as well. Ado-files inside the package archive can be configured to make an automatic call to the host server to check for available updates.

Enhanced Current Capability for Modular Multilevel Converters by a Combined Sorting Algorithm for Capacitor Voltages and Semiconductor Losses

The modular multilevel converter (MMC) has become very attractive for high- and medium-voltage applications, generating excellent waveforms at very high efficiencies. One of the main challenges is the appropriate selection of inserted submodules (SMs), commonly done by capacitor voltage balancing algorithms. However, the semiconductor stress can only be balanced up to a certain degree by conventional algorithms, since the stress is not directly monitored. An uneven stress distribution between the SMs does not only result in different lifetime expectations, but also in increased maximum temperatures, for which each SM needs to be designed. With the goal of more effective utilization of chip area, a new balancing approach is introduced for monitoring and balancing not only the capacitor voltages but also the average power losses in each SM. In this way, the MMC current capability is significantly increased only by software without deteriorating the system performance and efficiency

UNLV New Horizons Band & Red Rock Saxophone Quartet & UNLV Symphonic Winds

Program listing performers and works performed

UNLV New Horizons Band & The Las Vegas Flute Ensemble & The UNLV Community Band

Program listing performers and works performed