Uma contribuição à teoria das contribuições

A insuficiente definição conceitual das contribuições, seja a nível constitucional, seja a nível do Código Tributário Nacional, tem possibilitado a instituição de contribuições especiais pela União Federal sem quase nenhum parâmetro de controle, exceto pelas exigências de afetação do produto da arrecadação a uma finalidade específica (social, econômica ou profissional) e de referibilidade dos benefícios ao grupo de contribuintes. Ocorre que o primeiro requisito (da afetação) é de dificílimo controle e tem sido pouco observado, enquanto que o segundo (da referibilidade) é um conceito ainda muito aberto e sujeito a uma interpretação elástica pelos tribunais, que tem reconhecido a sua existência mesmo nos casos em que a atuação estatal não se refere direta e imediatamente ao grupo de contribuintes. Isso, na prática, abriu à União Federal um campo de incidência quase ilimitado a explorar por meio da criação de contribuições que muitas vezes não passam de meros impostos com destinação especial, agravando os problemas de escalada da carga tributária, concentração das receitas tributárias na União Federal, crescente dependência de Estados e Municípios de transferências federais e perda da racionalidade do já precário Sistema Tributário Nacional. Em vista disso, o presente trabalho visa contribuir para o desenvolvimento da teoria das contribuições, identificando novos parâmetros jurídicos para a sua classificação, estruturação e controle. Por meio desses aportes teóricos, busca-se também conferir maior racionalidade e coerência ao Sistema Tributário Nacional, o que de maneira indireta também tende a contribuir para o desenvolvimento institucional do País.

An experimental based assessment of the deviation of the bearing characteristic frequencies

Slippage in the contact roller-races has always played a central role in the field of diagnostics of rolling element bearings. Due to this phenomenon, vibrations triggered by a localized damage are not strictly periodic and therefore not detectable by means of common spectral functions as power spectral density or discrete Fourier transform. Due to the strong second order cyclostationary component, characterizing these signals, techniques such as cyclic coherence, its integrated form and square envelope spectrum have proven to be effective in a wide range of applications. An expert user can easily identify a damage and its location within the bearing components by looking for particular patterns of peaks in the output of the selected cyclostationary tool. These peaks will be found in the neighborhood of specific frequencies, that can be calculated in advance as functions of the geometrical features of the bearing itself. Unfortunately the non-periodicity of the vibration signal is not the only consequence of the slippage: often it also involves a displacement of the damage characteristic peaks from the theoretically expected frequencies. This issue becomes particularly important in the attempt to develop highly automated algorithms for bearing damage recognition, and, in order to correctly set thresholds and tolerances, a quantitative description of the magnitude of the above mentioned deviations is needed. This paper is aimed at identifying the dependency of the deviations on the different operating conditions. This has been possible thanks to an extended experimental activity performed on a full scale bearing test rig, able to reproduce realistically the operating and environmental conditions typical of an industrial high power electric motor and gearbox. The importance of load will be investigated in detail for different bearing damages. Finally some guidelines on how to cope with such deviations will be given, accordingly to the expertise obtained in the experimental activity.

Composition deviation of arrays of FePt nanoparticles starting from poly(styrene)-poly(4-vinylpyridine) micelles

Ordered arrays of FePt nanoparticles were prepared using a diblock polymer micellar method combined with plasma treatment. Rutherford backscattering spectroscopy analyses reveal that the molar ratios of Fe to Pt in metal-salt-loaded micelles deviate from those when metal precursors are added, and that the plasma treatment processes have little influence upon the compositions of the resulting FePt nanoparticles. The results from Fourier transform infrared spectroscopy show that the maximum loadings of FeCl3 and H2PtCl6 inside poly( styrene)-poly(4-vinylpyridine) micelles are different. The composition deviation of FePt nanoparticles is attributed to the fact that one FeCl3 molecule coordinates with a single 4-vinylpyridine (4VP) unit, while two neighboring and uncomplexed 4VP units are required for one H2PtCl6 molecule. Additionally, we demonstrate that the center-to-center distances of the neighboring FePt nanoparticles can also be tuned by varying the drawing velocity.

The distribution of sales revenues from pharmaceutical innovation.

OBJECTIVE: This report updates our earlier work on the returns to pharmaceutical research and development (R&D) in the US (1980 to 1984), which showed that the returns distributions are highly skewed. It evaluates a more recent cohort of new drug introductions in the US (1988 to 1992) and examines how the returns distribution is emerging for drugs with life cycles concentrated in the 1990s versus the 1980s. DESIGN AND SETTING: Methods were described in detail in our earlier reports. The current sample included 110 new drug entities (including 28 orphan drugs), and sales data were obtained for the period 1988 to 1998, which represented between 7 and 11 years of sales for the drugs included. 20 years was chosen as the expected market life for this cohort, and a 2-step procedure was used to project future sales for the drugs--during the period until patent expiry and then beyond patent expiry until the 20-year time-horizon was completed. Thus, the values in the first half of the life cycle are essentially based on realised sales, while those in the second half are projected using information on patent expiry and other inputs. MAIN OUTCOME MEASURES AND RESULTS: Peak annual sales for the top decile of drugs introduced between 1988 and 1992 in the US amounted to almost $US1.1 billion compared with peak sales of less than $US175 million (1992 values) for the mean compound. In particular, the top decile accounted for 56% of overall sales revenue. Although the sales distributions were skewed in both our earlier and current analysis, the top decile in the later time-period exhibited more rapid rates of growth after launch, a peak that was more than 50% greater in real terms than for the 1980 to 1984 cohort, and a faster rate of expected decline in sales after patent expiry. One factor contributing to the distribution of sales revenues becoming more skewed over time is the orphan drug phenomenon (i.e. most of the orphan drugs are concentrated at the bottom of the distribution). CONCLUSION: The distribution of sales revenues for new drug compounds is highly skewed in nature. In this regard, the top decile of new drugs accounts for more than half of the total sales generated by the 1988 to 1992 cohort analysed. Furthermore, the distribution of sales revenues for this cohort is more skewed than that of the 1980 to 1984 cohort we analysed in previous research.

Deviation of the alloimmune response toward tolerance by chimeric class I MHC molecules

Class I major histocompatibility complex (MHC) molecules induce either accelerated rejection or prolonged survival of allografts, presumably because of the presence of immunogenic or tolerogenic epitopes, respectively. To explore the molecular basis of this phenomenon, three chimeric class I molecules were constructed by substituting the rat class I RT1.A$\sp{\rm a}$ sequences with the N-terminus of HLA-A2.1 (N$\sp{\rm HLA-A2.1}$-RT1.A$\sp{\rm a}$), the $\alpha\sb1$ helix (h) with $\rm\alpha\sb{1h}\sp{u}$ sequences ( ($\rm\alpha\sb{1h}\sp{u}$) -RT1.A$\sp{\rm a}$) or the entire $\alpha\sb2$ domain (d) with $\rm\alpha\sb{2d}\sp{u}$ sequences ( ($\rm\alpha\sb{2d}\sp{u}$) -RT1.A$\sp{\rm a}$). Wild type (WT) and chimeric cDNAs were sequenced prior to transfection into Buffalo (BUF; RT1$\sp{\rm b}$) hepatoma cells. Stable transfectants were injected subcutaneously (s.c.) into different hosts 7 days prior to challenge with a heart allograft. In BUF hosts, chimeric ($\rm\alpha\sb{1h}\sp{u}$) -RT1.A$\sp{\rm a}$ accelerated the rejection of Wistar Furth (WF; RT1$\sp{\rm u}$) heart allografts, but had no effect on the survival of ACI (RT1$\sp{\rm a}$) grafts. In contrast, the ($\rm\alpha\sb{2d}\sp{u}$) -RT1.A$\sp{\rm a}$ (containing $\rm\alpha\sb{1d}\sp{a}$ sequences) immunized BUF recipients toward RT1$\sp{\rm a}$ grafts. In WF hosts, WT-RT1.A$\sp{\rm a}$ was a potent immunogen and accelerated ACI graft rejection, N$\sp{\rm HLA-A2.1}$-RT1.A$\sp{\rm a}$ was less effective and ($\rm\alpha\sb{\rm 1h}\sp{u}\rbrack$-RT1.A$\sp{\rm a}$ was not immunogenic. Thus, dominant and subdominant epitopes inducing in vivo sensitization to cardiac allografts are present in the $\alpha\sb1$ helix and the N-terminus, respectively. The failure of ($\rm\alpha\sb{2d}\sp{u}$) -RT1.A$\sp{\rm a}$ transfectants (containing recipient-type $\alpha\sb{\rm 2d}$ sequences) to sensitize WF hosts toward ACI (RT1$\sp{\rm a}$) grafts, despite the presence of donor-type immunogenic $\alpha\sb{\rm 1d}\sp{\rm a}$, suggests that "self-$\alpha\sb2$" sequences displayed on chimeric antigens interfere with immunogenicity. The ($\rm\alpha\sb{1h}\sp{u}$) -RT1.A$\sp{\rm a}$ transfectants injected s.c. prolonged the survival of WF (RT1$\sp{\rm u}$) hearts in ACI (RT1$\sp{\rm a}$) recipients. Furthermore, intra-portal injection of extracts from ($\rm\alpha\sb{1h}\sp{u}$) -RT1.A$\sp{\rm a}$, but not WT-RT1.A$\sp{\rm a}$ or RT1.A$\sp{\rm u}$, in conjunction with a brief cyclosporine course rendered ACI hosts permanently and specifically tolerant to donor-type WF cardiac allografts. Thus, immunodominant allodeterminants are present in the $\alpha\sb1$, but not the $\alpha\sb2$, domain of rat class I MHC molecules. Furthermore, the $\rm\alpha\sb{1h}\sp{u}$ immunogenic epitopes trigger tolerogenic responses when flanked by host-type N-terminal$\sp{\rm a}$ and $\rm\alpha\sb{2d}\sp{a}$ sequences. ^

Estimating the mean and standard deviation of concentration distributions using censored samples

Environmental data sets of pollutant concentrations in air, water, and soil frequently include unquantified sample values reported only as being below the analytical method detection limit. These values, referred to as censored values, should be considered in the estimation of distribution parameters as each represents some value of pollutant concentration between zero and the detection limit. Most of the currently accepted methods for estimating the population parameters of environmental data sets containing censored values rely upon the assumption of an underlying normal (or transformed normal) distribution. This assumption can result in unacceptable levels of error in parameter estimation due to the unbounded left tail of the normal distribution. With the beta distribution, which is bounded by the same range of a distribution of concentrations, $\rm\lbrack0\le x\le1\rbrack,$ parameter estimation errors resulting from improper distribution bounds are avoided. This work developed a method that uses the beta distribution to estimate population parameters from censored environmental data sets and evaluated its performance in comparison to currently accepted methods that rely upon an underlying normal (or transformed normal) distribution. Data sets were generated assuming typical values encountered in environmental pollutant evaluation for mean, standard deviation, and number of variates. For each set of model values, data sets were generated assuming that the data was distributed either normally, lognormally, or according to a beta distribution. For varying levels of censoring, two established methods of parameter estimation, regression on normal ordered statistics, and regression on lognormal ordered statistics, were used to estimate the known mean and standard deviation of each data set. The method developed for this study, employing a beta distribution assumption, was also used to estimate parameters and the relative accuracy of all three methods were compared. For data sets of all three distribution types, and for censoring levels up to 50%, the performance of the new method equaled, if not exceeded, the performance of the two established methods. Because of its robustness in parameter estimation regardless of distribution type or censoring level, the method employing the beta distribution should be considered for full development in estimating parameters for censored environmental data sets. ^

Deviation of Cup and Propeller Anemometer Calibration Results with Air Density

The effect of air density variations on the calibration constants of several models of anemometers has been analyzed. The analysis was based on a series of calibrations between March 2003 and February 2011. Results indicate a linear behavior of both calibration constants with the air density. The effect of changes in air density on the measured wind speed by an anemometer was also studied. The results suggest that there can be an important deviation of the measured wind speed with changes in air density from the one at which the anemometer was calibrated, and therefore the need to take this effect into account when calculating wind power estimations.