Robustness issues for <Emphasis Type="SmallCaps">cub</Emphasis> models

The present paper deals with a parametric class of models implemented for ordered categorical data, denoted as cub  model, which is defined as a discrete mixture of a shifted binomial and a uniform random variable. For these models, robustness issues are considered. In particular, the influence function is introduced and subsequently used to define the robustness measures for categorical data. By exploiting the peculiar parametrization of the cub  models, diagnostic plots are proposed which allow to display the effect of a contamination in the data, simultaneously for all categories. The breakdown point is also considered and a computational procedure is suggested to determine an upper bound. The paper provides evidence that, despite the limited range of the support, contaminations in the data can heavily affect the inferential procedures and hence robustness topics are indeed relevant for ordinal data.     

Modelling and simulation of a lighting control system

The objective of this paper was to regulate the amount of illumination in a room at a constant level, irrespective of the disturbances from outside such as weather conditions or the use of blinds to avoid the glare risk. In order to produce a model of the lighting system in our project, the supply voltage to the lamp dimmer circuits was varied stepwise and the resulting response – measured by the light sensors – was captured with a data-acquisition board. A nonlinear static characteristic in series with a linear 3rd order dynamic system was obtained from this experiment. The model was then used to implement and to validate a lighting system simulator, which was then further used to design, tune, test and evaluate efficient lighting controllers. The control design was rather challenging because the system is highly nonlinear and because undesired interaction occurs between multiple illumination zones in a big office room. The main benefits are a higher level of comfort and a continuous saving of energy.     

Occurrence of residues of veterinary antibiotics in water,sediment and trout tissue (Oncorhynchus mykiss) in the southern area of Lake Titicaca,Peru

The city of Puno in Peru is the largest producer of trout (Oncorhynchus mykiss) using intensive floating cage systems installed in Lake Titicaca. As a result, the increase in diseases and the use of antibiotics to control them during the production cycle has been documented. We study the impact of antibiotics on drinking water, trout tissues and the lake's aquatic ecosystem. Nine antibiotics were monitored: tetracyclines, sulfonamides and fluoroquinolones. The samples were collected randomly and analyzed by liquid chromatography coupled to mass spectrometry and the solid-phase extraction system. The sediment samples and surface water samples contain high concentrations of antibiotics. All sediments contain fluoroquinolones (3.74 mg kg^?1) and tetracyclines (3.08 mg kg^?1) and the surface water contains fluoroquinolones of up to 408.2 and 652.7 ng L^?1 in the dry and rainy seasons respectively (P > 0.05). Drinking water samples from the city of Puno collected at sampling points with Lake Titicaca as a source of drinking water, reached an average of 188.1 and 222.2 ng L^?1 of ciprofloxacin in dry and rainy seasons respectively. Complementarily, in trout tissues, it reached 7.8 μg kg^?1 in oxytetracycline 8.7 μg kg^?1 in sulfatizole, 4.2 μg kg^?1 in ciprofloxacin and 3.6 μg kg^?1 in sarafloxacin. The presence of these antibiotics in surface water is attributed to the aquaculture activity, in addition to runoff and wastewater, and their presence can have detrimental effects on the aquatic ecosystem, and even affect public health due to the consumption of aquaculture products and drinking water contaminated with antibiotic residues.     

Development of a vehicle–track interaction model to predict the vibratory benefits of rail grinding in the time domain

Imperfections in the wheel–rail contact are one of the main sources of generation of railway vibrations. Consequently, it is essential to take expensive corrective maintenance measures, the results of which may be unknown. In order to assess the effectiveness of these measures, this paper develops a vehicle–track interaction model in the time domain of a curved track with presence of rail corrugation on the inner rail. To characterize the behavior of the track, a numerical finite element model is developed using ANSYS software, while the behavior of the vehicle is characterized by a unidirectional model of two masses developed with VAMPIRE PRO software. The overloads obtained with the dynamic model are applied to the numerical model and then, the vibrational response of the track is obtained. Results are validated with real data and used to assess the effectiveness of rail grinding in the reduction of wheel–rail forces and the vibration generation phenomenon.

     

Tetraoctylammonium,a Long Chain Quaternary Ammonium Blocker,Promotes a Noncollapsed,Resting-Like Inactivated State in KcsA

Alkylammonium salts have been used extensively to study the structure and function of potassium channels. Here, we use the hydrophobic tetraoctylammonium (TOA⁺) to shed light on the structure of the inactivated state of KcsA, a tetrameric prokaryotic potassium channel that serves as a model to its homologous eukaryotic counterparts. By the combined use of a thermal denaturation assay and the analysis of homo-Förster resonance energy transfer in a mutant channel containing a single tryptophan (W67) per subunit, we found that TOA⁺ binds the channel cavity with high affinity, either with the inner gate open or closed. Moreover, TOA⁺ bound at the cavity allosterically shifts the equilibrium of the channel’s selectivity filter conformation from conductive to an inactivated-like form. The inactivated TOA⁺–KcsA complex exhibits a loss in the affinity towards permeant K⁺ at pH 7.0, when the channel is in its closed state, but maintains the two sets of K⁺ binding sites and the W67–W67 intersubunit distances characteristic of the selectivity filter in the channel resting state. Thus, the TOA⁺–bound state differs clearly from the collapsed channel state described by X-ray crystallography and claimed to represent the inactivated form of KcsA.     

Family Dynamics and First-Time Homeownership

The transition to first-time homeownership is related to household events such as cohabitation and marriage as well as to parents' homeownership. This paper investigates how these relationships have changed during the last few decades, using the first wave of the Netherlands Kinship Panel Study and event history analysis techniques, including interaction effects with the calendar year. The study finds that singles, cohabiters and those who are just starting cohabitation have become more likely to be first-time homeowners than married people without children. The data did not provide evidence for changes in the importance of the intergenerational transmission of homeownership.     

Entertainment–Retail Centres in Hong Kong and Los Angeles: Trends and Lessons

This paper examines the evolution and recent trends in the design of Entertainment Retail Centres (ERCs) in Los Angeles and Hong Kong. Most of the literature on spaces of consumption and leisure deals with economic reasons for the development of these spaces, and with the social, cultural, and political implications of the phenomenon. There are limitations to this approach that this study addresses. First, there has been a lack of attention to processes of globalization in the analysis of these spaces. Furthermore, a largely US-centred approach has left out an understanding of the significance of the ERC phenomenon in other societies. Secondly, the literature lacks a sufficient appreciation of the particularities of urban planning and design associated with ERCs. A body of work addresses the issues of the organization of space within the mall, and its architectonics. However, these studies are by definition limited to the complex, and not oriented towards the urban setting. This paper seeks to address these gaps by moving towards an understanding of the relationship of entertainment retail spaces to their urban and glocal contexts. It considers ERCs not only for the construction of economics, but also of urban, social, and cultural forces, and simultaneously as agents for the mediation of these forces in the built environment of localized places. The analysis is organized along four related themes—land use, transportation, urban design, and consumption patterns. The conclusion offers lessons that can orient both these global cities' trajectories and those of the cities that follow in their footsteps.     

Nonisothermal crystallization of isotactic polypropylene blended with poly(α-pinene). I. Bulk crystallization

The influence of a natural terpene resin, poly(α-pinene) (PαP), on the nonisothermal crystallization process of isotactic polypropylene (iPP) was investigated. The solidification process strongly depends on cooling rate, composition, and miscibility of the system. For the blends containing PαP up to 30 wt %, the overall nonisothermal crystallization rate is depressed with respect to plain iPP. This is probably the result of the diluting effect of the polyterpene because the two components are miscible. The 50/50 blend presents, instead, two amorphous phases: an iPP-rich phase and a PαP-rich phase. For this composition, solidification starts at temperatures higher than those for plain iPP and blends with lower PαP content, given that the diluting effect of PαP in the iPP-rich phase is counterweighted by an increased number of nuclei that originate from the polyterpene-rich phase domains. PαP also influences the morphology of iPP spherulites, which are spherical in plain iPP and become more irregular with increasing PαP content. The number and dimension of iPP spherulites depend on blend composition and miscibility of the components. Moreover, the nonisothermal crystallization kinetics of iPP/PαP blends was analyzed with the Ozawa equation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 358–367, 2001     

Eye-tracking dysfunction and birth-month weather in schizophrenia.

The prevalence of eye-tracking dysfunction (ETD) is significantly elevated in individuals with a diagnosis of schizophrenia and in their nonschizophrenic relatives, suggesting that ETD marks a familial (most likely genetic) risk factor for schizophrenia. Birth in a season with intemperate weather is also a widely reported risk factor for schizophrenia and is particularly marked for the subgroup with no family history of the disorder. This study examined how these two risk factors covaried in 78 patients with a Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev.; American Psychiatric Association, 1987) diagnosis of schizophrenia. Eye tracking and birth-month weather were independently assessed. As hypothesized, patients without ETD were significantly more likely to be born in months with intemperate weather (both hot and cold) than either patients with ETD or people in the general population. Etiologic factors associated with severe weather near birth may be important sources of nonfamilial schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)