The performance of non‐linear exchange rate models: a forecasting comparison

In recent years there has been a considerable development in modelling non‐linearities and asymmetries in economic and financial variables. The aim of the current paper is to compare the forecasting performance of different models for the returns of three of the most traded exchange rates in terms of the US dollar, namely the French franc (FF/$), the German mark (DM/$) and the Japanese yen (Y/$). The relative performance of non‐linear models of the SETAR, STAR and GARCH types is contrasted with their linear counterparts. The results show that if attention is restricted to mean square forecast errors, the performance of the models, when distinguishable, tends to favour the linear models. The forecast performance of the models is evaluated also conditional on the regime at the forecast origin and on density forecasts. This analysis produces more evidence of forecasting gains from non‐linear models. Copyright © 2002 John Wiley & Sons, Ltd.     

A word of the Empirics: the ancient concept of observation and its recovery in early modern medicine

The genealogy of observation as a philosophical term goes back to the ancient Greek astronomical and medical traditions, and the revival of the concept in the Renaissance also happened in the astronomical and medical context. This essay focuses primarily on the medical genealogy of the concept of observation. In ancient Greek culture, an elaboration of the concept of observation (tērēsis) first emerged in the Hellenistic age with the medical sect of the Empirics, to be further developed by the ancient Sceptics. Basically unknown in the Middle Ages, the Empirics' conceptualisation of tērēsis trickled back into Western medicine in the fourteenth century, but its meaning seems to have been fully recovered by European scholars only in the 1560s, concomitantly with the first Latin translation of the works of Sextus Empiricus. As a category originally associated with medical Scepticism, observatio was a new entry in early modern philosophy. Although the term gained wide currency in general scholarly usage in the seventeenth century, its assimilation into standard philosophical language was very slow. In fact, observatio does not even appear as an entry in the philosophical dictionaries until the eighteenth century--with one significant exception, the medical lexica, which featured the lemma, reporting its ancient Empiric definition, as early as 1564.     

Comparing ex-ante forecasts from a sem and var model: An application to the italian economy

The predictive performance of a large-scale structural econometric model (SEM) of the Italian economy the Prometeia model is compared in this paper with a vector autoregressive (VAR) model estimated for a selection of six main variables of interest. The paper concentrates on the quarterly ex-ante forecasts of GDP growth rate and the annual forecasts of GDP growth and inflation rate, over the period 1980-85. It concludes that no forecaster is systematically better than the other. In particular, the VAR model outperforms the SEM in short-run forecasts, suggesting that, for the latter, more careful attention should be addressed to questions of dynamic specification. On the other hand, for longer intervals, the SEM forecasts are more accurate than the VAR forecasts, in that they can benefit from the judgemental interventions of the model users and the model can pick up the non-linearities of the economy which cannot be captured by the VAR. Given the different kinds of information that can be extracted from the two approaches, it seems more reasonable to consider them as complementary rather than alternative tools for modelling and forecasting. Therefore, rather than attempting to establish the superiority of one type of model over the other, this kind of comparisons should be seen as a useful diagnostic tool for detecting types of model misspecification.     

Aggressive,omnivorous, invasive: the Erythraean moon crab Matuta victor (Fabricius, 1781) (Crustacea: Decapoda: Matutidae) in the eastern Mediterranean sea

Since its first sighting in 2012 in Haifa Bay, Israel, the population of the Indo-Pacific moon crab, Matuta victor, has increased greatly along the Israeli littoral and spread to Lebanon and the Mediterranean coast of Turkey. To examine possible interactions with the Levantine nearshore psammophilic community, the crab’s feeding behaviour was observed in situ and the foregut contents of 69 specimens collected in December 2015 and June 2016 were analysed. Its omnivorous diet was confirmed and previously unknown intraspecific competitive feeding behaviour is reported. The agonistic behaviour may denote behavioural flexibility that enables the crabs to colonize and persist in a depauperate novel habitat. Site-specific disturbance regimen related to human activities seems to have had a critical role in driving the rapid population increase.     

FAN1 mutations cause karyomegalic interstitial nephritis, linking chronic kidney failure to defective DNA damage repair

Chronic kidney disease (CKD) represents a major health burden. Its central feature of renal fibrosis is not well understood. By exome sequencing, we identified mutations in FAN1 as a cause of karyomegalic interstitial nephritis (KIN), a disorder that serves as a model for renal fibrosis. Renal histology in KIN is indistinguishable from that of nephronophthisis, except for the presence of karyomegaly. The FAN1 protein has nuclease activity and acts in DNA interstrand cross-link (ICL) repair within the Fanconi anemia DNA damage response (DDR) pathway. We show that cells from individuals with FAN1 mutations have sensitivity to the ICL-inducing agent mitomycin C but do not exhibit chromosome breakage or cell cycle arrest after diepoxybutane treatment, unlike cells from individuals with Fanconi anemia. We complemented ICL sensitivity with wild-type FAN1 but not with cDNA having mutations found in individuals with KIN. Depletion of fan1 in zebrafish caused increased DDR, apoptosis and kidney cysts. Our findings implicate susceptibility to environmental genotoxins and inadequate DNA repair as novel mechanisms contributing to renal fibrosis and CKD.