Distributional equivalence and subcompositional coherence in the analysis of contingency tables, ratio-scale measurements and compositional data

We consider two fundamental properties in the analysis of two-way tables of positive data: the principle of distributional equivalence, one of the cornerstones of correspondence analysis of contingency tables, and the principle of subcompositional coherence, which forms the basis of compositional data analysis. For an analysis to be subcompositionally coherent, it suffices to analyse the ratios of the data values. The usual approach to dimension reduction in compositional data analysis is to perform principal component analysis on the logarithms of ratios, but this method does not obey the principle of distributional equivalence. We show that by introducing weights for the rows and columns, the method achieves this desirable property. This weighted log-ratio analysis is theoretically equivalent to spectral mapping , a multivariate method developed almost 30 years ago for displaying ratio-scale data from biological activity spectra. The close relationship between spectral mapping and correspondence analysis is also explained, as well as their connection with association modelling. The weighted log-ratio methodology is applied here to frequency data in linguistics and to chemical compositional data in archaeology.

Pitfalls in the modeling of forward-looking price setting and investment decisions

The present paper makes progress in explaining the role of capital for inflation and output dynamics. We followWoodford (2003, Ch. 5) in assuming Calvo pricing combined with a convex capital adjustment cost at the firm level. Our main result is that capital accumulation affects inflation dynamics primarily through its impact on the marginal cost. This mechanism is much simpler than the one implied by the analysis in Woodford's text. The reason is that his analysis suffers from a conceptual mistake, as we show. The latter obscures the economic mechanism through which capital affects inflation and output dynamics in the Calvo model, as discussed in Woodford (2004).

Characterization of instrumental and sensory quality of papaya ‘Solo' and 'Local' produced in Santiago - Cape Verde and critical analysis on the importation of papaya

O estudo teve por objectivo fazer a caracterização dos atributos de qualidade de duas variedades (Solo e Local) de papaia produzida em Santiago, Cabo Verde, e definir os atributos que os distribuidores procuram. Foram realizadas avaliações físico-químicas, sensorial e um estudo de mercado. Os parâmetros avaliados foram o peso, cor interior e exterior, textura, espessura da polpa, pH, acidez titulável, SST, fez-se avaliação sensorial a aplicação de um questionário aos importadores de papaia. Os parâmetros SST, Acidez, pH e peso variam significativamente com as variedades, sendo as papaias da variedade Local mais pesadas. A textura varia em função dos graus de maturação, a firmeza apresenta uma diminuição ao longo do amadurecimento, na deformação percebe-se um decréscimo com avançar da maturação, nos parâmetros de cor interna e externa as diferenças encontram-se na interacção entre Variedade e Estado de maturação. A variedade Solo foi mais valorizada na avaliação sensorial assim como no preço, certificação/selo qualidade e doçura pelos distribuidores.

How important are tobacco prices in the propensity to start and quit smoking? An analysis of smoking histories from the Spanish National Health Survey

This paper analyses the effect of tobacco prices on the propensity tostart and quit smoking using a pool of the 1993, 1995 and 1997 editionsof the Spanish National Health Surveys. The estimates for severalparametric models of the hazard rate for starting and quitting suggestthat i) The public health measures applied as of 1992 have had asignificative effect on both reducing the hazard of starting andincreasing the hazard of quitting, ii) Prices have a very weak effect onthe hazard of starting in the male population and no significant effectin the female population, iii) The price floor of cigarrettes, proxiedby the average price of a pack of black cigarrettes, has a significanteffect on the quitting hazard which is robust across specifications andapplies to both men and women. The implied price elasticity of the timeup to quitting is situated around -1.4.

The new Keynesian approach to monetary policy analysis: Lessons and new directions

I discuss several lessons regarding the design and conduct of monetary policy that have emerged out of the New Keynesian research program. Those lessons include the bene.ts of price stability, the gains from commitment about future policies, the importance of nat-ural variables as benchmarks for policy, and the bene.ts of a credible anti-inflationary stance. I also point to one challenge facing NK modelling efforts: the need to come up with relevant sources of policy tradeoffs. A potentially useful approach to meeting that challenge, based on the introduction of real imperfections, is presented.

Inflation dynamics: A structural econometric analysis

We develop and estimate a structural model of inflation that allowsfor a fraction of firms that use a backward looking rule to setprices. The model nests the purely forward looking New KeynesianPhillips curve as a particular case. We use measures of marginalcosts as the relevant determinant of inflation, as the theorysuggests, instead of an ad-hoc output gap. Real marginal costsare a significant and quantitatively important determinant ofinflation. Backward looking price setting, while statisticallysignificant, is not quantitatively important. Thus, we concludethat the New Keynesian Phillips curve provides a good firstapproximation to the dynamics of inflation.

First price auctions: Monotonicity and uniqueness

I study monotonicity and uniqueness of the equilibrium strategies in a two-person first price auction with affiliated signals. I show thatwhen the game is symmetric there is a unique Nash equilibrium thatsatisfies a regularity condition requiring that the equilibrium strategies be{\sl piecewise monotone}. Moreover, when the signals are discrete-valued, the equilibrium is unique. The central part of the proof consists of showing that at any regular equilibrium the bidders' strategies must be monotone increasing within the support of winning bids. The monotonicity result derived in this paper provides the missing link for the analysis of uniqueness in two-person first price auctions. Importantly, this result extends to asymmetric auctions.

A dynamic analysis of human welfare in a warming planet

Climate science indicates that climate stabilization requires low GHG emissions. Is thisconsistent with nondecreasing human welfare?Our welfare or utility index emphasizes education, knowledge, and the environment. Weconstruct and calibrate a multigenerational model with intertemporal links provided by education,physical capital, knowledge and the environment.We reject discounted utilitarianism and adopt, first, the Pure Sustainability Optimization (orIntergenerational Maximin) criterion, and, second, the Sustainable Growth Optimization criterion,that maximizes the utility of the first generation subject to a given future rate of growth. We applythese criteria to our calibrated model via a novel algorithm inspired by the turnpike property.The computed paths yield levels of utility higher than the level at reference year 2000 for allgenerations. They require the doubling of the fraction of labor resources devoted to the creation ofknowledge relative to the reference level, whereas the fractions of labor allocated to consumptionand leisure are similar to the reference ones. On the other hand, higher growth rates requiresubstantial increases in the fraction of labor devoted to education, together with moderate increasesin the fractions of labor devoted to knowledge and the investment in physical capital.

Summary of Real Estate Assessment, 2009

The most important aspect of property taxation is the concept that all property should be valued for tax purposes on a uniform basis so that the actual property tax burden can be distributed equitably among individual property owners. One of the most widely used and accepted methods of determining relative levels and uniformity of assessments is the assessment/sales ratio study. Such a study, in its most fundamental analysis, is the comparison of the assessed value of an individual property to its sale price. For example, a property assessed at $12,000 which sold for $26,000 would have an assessment/sales ratio of 46% ($12,000 ÷ $26,000). The purpose of this study is to provide assessment/sales ratio information that may be utilized by property tax administrators, local assessing officials, and interested taxpayers in examining the relative levels and uniformity of assessments throughout the State of Iowa. After further refinement, the study is one factor considered by the Director of Revenue in the biennial equalization of assessments.

Summary of Real Estate Assessment, 2008

The most important aspect of property taxation is the concept that all property should be valued for tax purposes on a uniform basis so that the actual property tax burden can be distributed equitably among individual property owners. One of the most widely used and accepted methods of determining relative levels and uniformity of assessments is the assessment/sales ratio study. Such a study, in its most fundamental analysis, is the comparison of the assessed value of an individual property to its sale price. For example, a property assessed at $12,000 which sold for $26,000 would have an assessment/sales ratio of 46% ($12,000 ÷ $26,000). The purpose of this study is to provide assessment/sales ratio information that may be utilized by property tax administrators, local assessing officials, and interested taxpayers in examining the relative levels and uniformity of assessments throughout the State of Iowa. After further refinement, the study is one factor considered by the Director of Revenue in the biennial equalization of assessments.

Changes in the use of broad-spectrum antibiotics after withdrawal of cefepime from the market: an interrupted time series analysis

Background and objective: Cefepime was one of the most used broad-spectrum antibiotics in Swiss public acute care hospitals. The drug was withdrawn from market in January 2007, and then replaced by a generic since October 2007. The goal of the study was to evaluate changes in the use of broad-spectrum antibiotics after the withdrawal of the cefepime original product. Design: A generalized regression-based interrupted time series model incorporating autocorrelated errors assessed how much the withdrawal changed the monthly use of other broad-spectrum antibiotics (ceftazidime, imipenem/cilastin, meropenem, piperacillin/ tazobactam) in defined daily doses (DDD)/100 bed-days from January 2004 to December 2008 [1, 2]. Setting: 10 Swiss public acute care hospitals (7 with\200 beds, 3 with 200-500 beds). Nine hospitals (group A) had a shortage of cefepime and 1 hospital had no shortage thanks to importation of cefepime from abroad. Main outcome measures: Underlying trend of use before the withdrawal, and changes in the level and in the trend of use after the withdrawal. Results: Before the withdrawal, the average estimated underlying trend (coefficient b1) for cefepime was decreasing by -0.047 (95% CI -0.086, -0.009) DDD/100 bed-days per month and was significant in three hospitals (group A, P\0.01). Cefepime withdrawal was associated with a significant increase in level of use (b2) of piperacillin/tazobactam and imipenem/cilastin in, respectively, one and five hospitals from group A. After the withdrawal, the average estimated trend (b3) was greatest for piperacillin/tazobactam (+0.043 DDD/100 bed-days per month; 95% CI -0.001, 0.089) and was significant in four hospitals from group A (P\0.05). The hospital without drug shortage showed no significant change in the trend and the level of use. The hypothesis of seasonality was rejected in all hospitals. Conclusions: The decreased use of cefepime already observed before its withdrawal from the market could be explained by pre-existing difficulty in drug supply. The withdrawal of cefepime resulted in change in level for piperacillin/tazobactam and imipenem/cilastin. Moreover, an increase in trend was found for piperacillin/tazobactam thereafter. As these changes generally occur at the price of lower bacterial susceptibility, a manufacturers' commitment to avoid shortages in the supply of their products would be important. As perspectives, we will measure the impact of the changes in cost and sensitivity rates of these antibiotics.

Analysis, modelling and classification of geospatial data using machine learning

The research considers the problem of spatial data classification using machine learning algorithms: probabilistic neural networks (PNN) and support vector machines (SVM). As a benchmark model simple k-nearest neighbor algorithm is considered. PNN is a neural network reformulation of well known nonparametric principles of probability density modeling using kernel density estimator and Bayesian optimal or maximum a posteriori decision rules. PNN is well suited to problems where not only predictions but also quantification of accuracy and integration of prior information are necessary. An important property of PNN is that they can be easily used in decision support systems dealing with problems of automatic classification. Support vector machine is an implementation of the principles of statistical learning theory for the classification tasks. Recently they were successfully applied for different environmental topics: classification of soil types and hydro-geological units, optimization of monitoring networks, susceptibility mapping of natural hazards. In the present paper both simulated and real data case studies (low and high dimensional) are considered. The main attention is paid to the detection and learning of spatial patterns by the algorithms applied.

Oscar Wilde. 'Camma', a severe and hedonic aesthetic correction of Plutarch's ethics

The aim of this article is to present an accurate analysis of O. Wilde's poem 'Camma' by referring it to its Greek model: that Camma both in Plutarch's Amatorius (Eroticus) and Mulierum Virtutes. It is precisely this accurate reading which permits us to verify how Plutarch's Ethics is corrected from the parameters of the hedonism which is peculiar to O. Wilde's aestheticism, thus turning Camma into a symbol of a pleasant life.

SF 2088 Convenience Fees Analysis and Recommendations, November 16, 2011

As an expansion of SF2088, the Department of Administrative Services-Information Technology Enterprise (DAS-ITE) was asked to further analyze the potential costs and savings if the current practice of charging credit card and overhead fees (“value-added fees”) were to be eliminated. Value-added fees reflect the costs an agency incurs while providing online services, and those costs will always exist.. DAS-ITE researched these costs and identified ways of making the associated fees less burdensome to the citizens of Iowa. The three alternatives provide different ways in which agencies can recover those costs; they could be borne by either an annual appropriation or adjustment of the online service “price” to include the fees within the cost of the online transaction. An additional alternative is presented to leave the current value-added fee practices in place. Recognition must also be made of the fact that traditional forms of conducting business with the State of Iowa, face-to-face and paper-based transactions, are inherently more costly. These delivery channels are effectively subsidized by the agency as a “cost of doing business” and the associated expense of the transactions is not passed on to the customer.

Relación precio-calidad de los destinos turísticos españoles de sol y playa

The aim of this article is to estímate price-quality relatíon of Spain resorts from ‘sun and beach’ segment. This study uses initially observed prices, but after obtains net pnces -estimated-, discounting services and characteristics prices. Methodologically, this article is based in hedonic methods, often used in economic analysis. Results show important differences between ‘prices observed’ and ‘adjusted prices’ by services and characteristics. Empirical results obtained in this article should be useful for taking decisions from public and prívate agents