Macro Effects on Agricultural Prices in Different Time Horizons

Using monthly data covering 1974:1 to 2002:12, this paper explores the linkage between changes in macroeconomic variables (real exchange rate and inflation rate) and changes in relative agricultural prices in different time horizons (1, 12, 24, 36, 48, and 60 months). By controlling factors that determine the long-run trend of relative agricultural prices, the results show that long-term changes in real exchange rates have had a significant negative correlation with the long-term changes in relative agricultural prices. Conversely, changes in the general price significantly affect short-term changes in the relative agricultural price.Relative agricultural price, exchange rates, inflation rates, unit root test, canonical cointegration regression, money neutrality, Demand and Price Analysis,

Assessing water availability in Mediterranean regions affected by water conflicts through MODIS data time series analysis

Water scarcity is a widespread problem in arid and semi-arid regions such as the western Mediterranean coastal areas. The irregularity of the precipitation generates frequent droughts that exacerbate the conflicts among agriculture, water supply and water demands for ecosystems maintenance. Besides, global climate models predict that climate change will cause Mediterranean arid and semi-arid regions to shift towards lower rainfall scenarios that may exacerbate water conflicts. The purpose of this study is to find a feasible methodology to assess current and monitor future water demands in order to better allocate limited water resources. The interdependency between a vegetation index (NDVI), land surface temperature (LST), precipitation (current and future), and surface water resources availability in two watersheds in southeastern Spain with serious difficulties in meeting water demands was investigated. MODIS (Moderate Resolution Imaging Spectroradiometer) NDVI and LST products (as proxy of drought), precipitation maps (generated from climate station records) and reservoir storage gauging information were used to compute times series anomalies from 2001 to 2014 and generate regression images and spatial regression models. The temporal relationship between reservoir storage and time series of satellite images allowed the detection of different and contrasting water management practices in the two watersheds. In addition, a comparison of current precipitation rates and future precipitation conditions obtained from global climate models suggests high precipitation reductions, especially in areas that have the potential to contribute significantly to groundwater storage and surface runoff, and are thus critical to reservoir storage. Finally, spatial regression models minimized spatial autocorrelation effects, and their results suggested the great potential of our methodology combining NDVI and LST time series to predict future scenarios of water scarcity.Published versio

Assessment of apparent nonstationarity in time series of annual inflow, daily precipitation, and atmospheric circulation indices: A case study from southwest Western Australia

The southwest region of Western Australia has experienced a sustained sequence of low annual inflows to major water supply dams over the past 30 years. Until recently, the dominant interpretation of this phenomenon has been predicated on the existence of one or more sharp breaks (change or jump points), with inflows fluctuating around relatively constant levels between them. This paper revisits this interpretation. To understand the mechanisms behind the changes, we also analyze daily precipitation series at multiple sites in the vicinity and time series for several indices of regional atmospheric circulation that may be considered as drivers of regional precipitation. We focus on the winter half-year for the region (May to October) as up to 80% of annual precipitation occurs during this "season". We find that the decline in the annual inflow is in fact more consistent with a smooth declining trend than with a sequence of sharp breaks, the decline is associated with decreases both in the frequency of daily precipitation occurrence and in wet-day amounts, and the decline in regional precipitation is strongly associated with a marked decrease in moisture content in the lower troposphere, an increase in regionally averaged sea level pressure in the first half of the season, and intraseasonal changes in the regional north-south sea level pressure gradient. Overall, our approach provides an integrated understanding of the linkages between declining dam inflows, declining precipitation, and changes in regional atmospheric circulation that favor drier conditions

The price stabilization effects of the EU entry price scheme for fruits and vegetables

The paper assesses the stabilization effects of the EU import regime for fresh fruit and vegetables based on the entry price system. The analysis is carried out on the EU prices of tomatoes and lemons and those of imports from some of the main competing countries on the EU domestic markets: Morocco, Argentina and Turkey. It is based on the estimation of a threshold vector autoregressive econometric model that is shown capable of taking the workings of the import regime into account. The model shows that prices behave differently when import prices are above/below the trigger entry price. This paper allowed to highlight the cases for which the isolation effect of EPS seems reached and the resulting stabilization effects

Relative Prices and Inflation: New Evidence from Different Inflationary Contexts

This paper analyzes the relationship between inflation and relative price variability, in the direction of the latter, in two countries with very different inflationary experiences: Argentina and Spain. To address this objective, using disaggregated price indexes (Wholesale Price Index for Argentina and Consumer Price Index for Spain), we delimitate different inflationary regimes and compute a set of regressions for each country. Our results suggest evidence in favor of the non-neutrality of inflation (mostly in hyperinflation periods) and do not support neither the menu costs nor the signal extraction approaches. We also detect significant structural changes in the relationship depending on the inflationary regime.inflation, relative price variability, inflation regimes, inflation volatility,expected and unexpected inflation.

SELECTED PAPER ABSTRACTS

Teaching/Communication/Extension/Profession,

The provision of wage insurance by the firm: evidence from a longitudinal matched employer-employee dataset

We evaluate the impact of product market uncertainty on workers wages, addressing the questions: To what extent do firms provide insurance to their workforce, insulating their wages from shocks in product markets? How does the amount of insurance provided vary with firm and worker attributes? We use a longitudinal matched employer-employee dataset of remarkable quality. The empirical strategy is based on Guiso et al. (2005). We first estimate dynamic models of sales and wages to retrieve consistent estimates of shocks to firms’ sales and to workers’ earnings. We are then able to estimate the sensitivity of wages to permanent and transitory shocks to firm performance. Results point to the rejection of the full insurance hypothesis. Workers’ wages respond to permanent shocks to firm performance, whereas they are not sensitive to transitory shocks. Managers are not fully insured against transitory shocks, while they receive the same protection against permanent shocks as workers in other occupations. Firms with higher variability in their sales, and those operating in di?erent industries, o?er more insurance against permanent shocks. Comparison with Guiso et al. (2005) indicates that Portuguese firms provide less insurance than Italian firms, corroborating evidence on the high degree of wage flexibility in Portugal.

Wheatering tight economic times: the sales evolution of consumer durables over the business cycle.

Despite its obvious importance, not much marketing research focuses on how business-cycle fluctuations affect individual companies and/or industries. Often, one only has aggregate information on the state of the national economy, even though cyclical contractions and expansions need not have an equal impact on every industry, nor on all firms in that industry. Using recent time-series developments, we introduce various measures to quantify the extent and nature of business-cycle fluctuations in sales. Specifically, we discuss the notions of cyclical volatility and cyclical comovement, and consider two types of cyclical asymmetry related, respectively, to the relative size of the peaks and troughs and the rate of change in upward versus downward parts of the cycle. In so doing, we examine how consumers adjust their purchasing behavior across different phases of the business cycle. We apply these concepts to a broad set (24) of consumer durables, for which we analyze the cyclical sensitivity in their sales evolution. In that way, we (i) derive a novel set of empirical generalizations, and (ii) test different marketing theory-based hypotheses on the underlying drivers of cyclical sensitivity. Consumer durables are found to be more sensitive to business-cycle fluctuations than the general economic activity, as expressed in an average cyclical volatility of more than four times the one in GNP, and an average comovement elasticity in excess of 2. This observation calls for an explicit consideration of cyclical variation in durable sales. Moreover, even though no evidence is found for depth asymmetry, the combined evidence across all durables suggests that asymmetry is present in the speed of up- and downward movements, as durables' sales falls much quicker during contractions than recover during economic expansions. Finally, key variables related to the industry's pricing activities, the nature of the durable (convenience vs. leisure), and the stage in a product's life cycle tend to moderate the extent of cyclical sensitivity in durable sales patterns.Business cycles; Companies; Consumer durables; Econometrics; Economy; Firms; Hypotheses; Industry; Information; Market; Marketing; Pricing; Product; Purchasing; Sales; Sales evolution; Sensitivity; Size; Time; Time-series econometrics; Time series; Variables; Volatility;

Report from GI-Dagstuhl Seminar 16394: Software Performance Engineering in the DevOps World

This report documents the program and the outcomes of GI-Dagstuhl Seminar 16394 "Software Performance Engineering in the DevOps World". The seminar addressed the problem of performance-aware DevOps. Both, DevOps and performance engineering have been growing trends over the past one to two years, in no small part due to the rise in importance of identifying performance anomalies in the operations (Ops) of cloud and big data systems and feeding these back to the development (Dev). However, so far, the research community has treated software engineering, performance engineering, and cloud computing mostly as individual research areas. We aimed to identify cross-community collaboration, and to set the path for long-lasting collaborations towards performance-aware DevOps. The main goal of the seminar was to bring together young researchers (PhD students in a later stage of their PhD, as well as PostDocs or Junior Professors) in the areas of (i) software engineering, (ii) performance engineering, and (iii) cloud computing and big data to present their current research projects, to exchange experience and expertise, to discuss research challenges, and to develop ideas for future collaborations

Statistically derived contributions of diverse human influences to twentieth-century temperature changes

The warming of the climate system is unequivocal as evidenced by an increase in global temperatures by 0.8 °C over the past century. However, the attribution of the observed warming to human activities remains less clear, particularly because of the apparent slow-down in warming since the late 1990s. Here we analyse radiative forcing and temperature time series with state-of-the-art statistical methods to address this question without climate model simulations. We show that long-term trends in total radiative forcing and temperatures have largely been determined by atmospheric greenhouse gas concentrations, and modulated by other radiative factors. We identify a pronounced increase in the growth rates of both temperatures and radiative forcing around 1960, which marks the onset of sustained global warming. Our analyses also reveal a contribution of human interventions to two periods when global warming slowed down. Our statistical analysis suggests that the reduction in the emissions of ozone-depleting substances under the Montreal Protocol, as well as a reduction in methane emissions, contributed to the lower rate of warming since the 1990s. Furthermore, we identify a contribution from the two world wars and the Great Depression to the documented cooling in the mid-twentieth century, through lower carbon dioxide emissions. We conclude that reductions in greenhouse gas emissions are effective in slowing the rate of warming in the short term.F.E. acknowledges financial support from the Consejo Nacional de Ciencia y Tecnologia (http://www.conacyt.gob.mx) under grant CONACYT-310026, as well as from PASPA DGAPA of the Universidad Nacional Autonoma de Mexico. (CONACYT-310026 - Consejo Nacional de Ciencia y Tecnologia; PASPA DGAPA of the Universidad Nacional Autonoma de Mexico