bluuebunny/crossref_metadata_2025 huggingface dataset:
La cohérence temporelle des anticipations de change : une étude sur données d'enquêtes
Authors: Benassy-Quéré Agnès , Raymond Hélène
Published: August 2011

The Temporal Consistency of Exchange Rate Expectations: A Study Using Survey Data by Agnès Bénassy-Quéré and Hélène Raymond

The consistency of forecasts concerning different dates is a less stringent assumption than that of rational expectations, frequently rejected by survey data. However, temporal consistency tests are conditional on the forecast modeling adopted. The temporal consistency assumption is tested here for expectations relating to four exchange rates conditional on four forecast models. Three different surveys are processed and several models estimated to guarantee reasonably general results. Nevertheless, these results need to be made relative to the explanatory capacity of each model. The three-month exchange rate forecasts appear to comply with a naive model, while the longer run forecasts are more in line with a mixed extrapolative-adjustive-regressive model in which the regressive component is often preponderant. This variety of models used depending on the future time periods explains why the temporal consistency assumption is often rejected and, consequently, strengthens the assumption of irrational expectations.
Fragilité des systèmes de change fixe et contrôle des capitaux
Authors: Bensaïd Bernard , Jeanne Olivier
Published: August 2011

Fragilité des systèmes de change fixe et contrôle des capitaux par Bernard Bensaïd et Olivier Jeanne

Nous étudions dans cet article la dynamique des crises de change sous les deux hypothèses suivantes. Premièrement, augmenter le taux d'intérêt nominal pour défendre la monnaie est coûteux, au delà d'un certain niveau, pour le gouvernement. Deuxièmement, le niveau de taux d'intérêt que le gouvernement est prêt à supporter avant de renoncer à défendre la monnaie n'est pas parfaitement connu par les acteurs du marché des changes. Nous montrons que sous ces conditions, des crises de change autoréalisatrices peuvent apparaître indépendamment des fondamentaux, et forcer le gouvernement à quitter le système de change fixe. Nous caractérisons ensuite les conditions sous lesquelles des contrôles des capitaux peuvent faire disparaître ce type d'instabilité.
Volatilité conditionnelle, signaux d'échange et perception du risque
Authors: Gallo Giampiero M. , Pacini Barbara
Published: August 2011

Conditional Volatility, Trading Signals and Risk Perception by Giampiero M. Gallo and Barbara Pacini

In this paper, we study the role of a conditional volatility term in modeling the presence of risk in the relationship between monthly spot and forward rates. We comment on the disappointing performance of the Garch-M model when used to study this relationship. This performance is due mainly to the high degree of persistence implied by the parametric estimation. In our view, a more flexible formulation should be adopted to model the risk premium and a distinction should be made between the alternating periods of weakness (when the risk premium is positive) and strength (when the risk premium is negative and becomes a risk discount). Taking three currencies against the deutschemark (French franc, Italian lira and pound sterling), we suggest a semiparametric estimator of the relationship, adopting a nonparametric measure of the conditional volatility. This enables us to consider the currency purchase and sale signals derived from technical analysis filters.
Mimétisme, erreurs d'anticipation de la demande et risque de défaillance des entreprises industrielles en France : un modèle économétrique à correction d'erreur
Authors: Blazy Régis
Published: August 2011

Imitation, Demand Expectation Errors and the Risk of Bankruptcy Among Industrial Firms in France: An

Econometric Error Correction Model

Régis Blazy

Our study links up the main explanatory factors generally put forward by theoretical literature as being behind the involuntary bankruptcy process by focusing on the role played by the demand expectation errors made by firms. The theoretical analysis presented posits a more or less stable convergence mechanism for these expectations. The effect of demand expectation errors on the probability of bankruptcy is econometrically confirmed using INSEE's business surveys of the industrial sector from 1977 to 1994. Other variables describing the legal, demographic and financial circumstances of firms during this period are also analysed.
La privatisation dans les pays en développement : déterminants et conséquences macro-économiques
Authors: Plane Patrick
Published: August 2011

Privatisation in the Developing Countries: Determining Factors and Macroeconomic Consequences

Patrick Plane

Determining factors behind privatisation are studied for the 1988-1992 period. The estimation of Probit and Tobit models on a sample of 35 developing countries suggests the statistically significant impact of four variables considered in 1988. These variables are the actual real exchange rate and three other variables expressed as a percentage of GDP: the market capitalisation ratio, the rate of indebtedness and direct investment. The introduction of privatisation probabilities or estimated values into the respective economic growth and investment explanatory models provides an interesting result. In this case, after checking for the effect of changes internal or external to the environment of the economies being studied, we do not reject the assumption that the government's withdrawal is behind an improvement in the economic situation.
Formation des anticipations de change : l'hypothèse d'un processus mixte
Authors: Prat Georges , Uctum Remzi
Published: August 2011

Formation of Exchange Rate Expectations: A Mixed Process Hypothesis Georges Prat and Remzi Uctum

This paper analyses how FF/$, DM/$ and Yen/$ exchange rate expectations form over three and twelve months. The basic principle uses the answers of a group of experts to the monthly Consensus Forecasts survey carried out since November 1989 (average of responses: "consensus"). The results obtained not only show that these "actual" expectations are not rational, but also that, when considered separately, the traditional extrapolative, regressive and adjustive procedures are unable to provide a valid explanation of these expectations. Overall, these results confirm those already obtained using other surveys.

The main breakthrough in this work is to show that by calculating a weighted average of the three traditional procedures, we obtain a satisfactory "explanation" of the exchange rate expectations found by Consensus Forecasts for the three currencies and the two time periods considered.
Effet du pouvoir de négociation et du marché local du travail sur la détermination des salaires
Authors: Smith Jennifer C.
Published: August 2011

Effet du pouvoir de négociation et du marché local du travail sur la détermination des salaires

par Jennifer C. Smith

Cet article utilise un panel de données original relatif à des groupes de négociation pour analyser certains aspects de la détermination des salaires dans les modèles du droit à gérer. Des mesures empiriques du pouvoir de négociation des syndicats et des firmes sont obtenues, qui apparaissent avoir un rôle important dans la détermination des salaires. L'influence des caractéristiques des syndicats sur la fixation des salaires est analysée. Les résultats confirment l'importance de ces dernières et apportent un nouvel éclairage sur les résultats obtenus par des études antérieures. De plus, nous montrons que non seulement la situation macro-économique, mais également les caractéristiques des marchés locaux du travail affectent les salaires négociés par delà la situation macro-économique.
Partage explicite ou implicite du profit dans la détermination des salaires
Authors: Bhargava Sandeep , Jenkinson Tim
Published: August 2011

Explicit Versus Implicit Profit Sharing and the Determination of Wages by Sandeep Bhargava and Tim Jenkinson

This paper considers the claim that explicit profit sharing reduces the marginal cost of labour. This is contrasted with the view that implicit profit sharing occurs through wage bargaining. Using a microeconomic data set from the U.K. we find no evidence that the introduction of profit sharing reduces base wages and, hence, the marginal cost of labour. However, firm profitability is found to have a positive effect on wages, which supports the hypothesis of implicite profit sharing through wage bargaining. These findings suggest that it is hard to justify the favourable tax treatment of profit-related pay found in the U.K.
Le marché du travail et l'évolution des salaires dans le transport aérien aux États-Unis : l'effet de la déréglementation de 1978
Authors: Crémieux Pierre-Yves
Published: August 2011

Le marché du travail et l'évolution des salaires dans le transport aérien aux États-Unis :

l'effet de la déréglementation de 1978 par Pierre- Yves Crémieux

En comparant les revenus observés avec des valeurs simulées, cette étude montre que les pilotes, les mécaniciens, et les agents de bord ont été affectés de façon très différente par la déréglementation du trafic aérien de 1978.

La déréglementation n'a pas eu d'effet statistiquement significatif sur les salaires des mécaniciens. Par contre, l'agent de bord représentatif a vu son revenu diminuer d'au moins 12 % entre 1978 et 1985 et d'au moins 39 % entre 1978 et 1992 par rapport à ce qu'il aurait été si la déréglementation n'avait pas eu lieu. Les revenus des pilotes étaient 12 et 22 % plus bas en 1985 et 1992 respectivement que si la déréglementation n'avait pas eu lieu. Les revenus des mécaniciens ont mieux résisté en raison de la plus grande transférabilité de leurs qualifications et des rentes plus limitées qu'ils avaient accumulées avant la déréglementation. Lorsqu'on additionne les effets de la déréglementation avec ceux de la récession américaine de 1982 et les changements dans le climat des relations industrielles aux États-Unis dans les années quatre-vingts, l'écart entre les valeurs prédites et les valeurs simulées s'accroît de façon significative pour les mécaniciens et les pilotes mais reste le même pour les agents de bord.
Estimation de relations de long terme sur données de panel : nouveaux résultats
Authors: Pirotte Alain
Published: August 2011

Estimation de relations de long terme sur données de panel : nouveaux résultats .

par Alain Pirotte

Cet article s'intéresse à la détermination des effets de long terme sur données de panel. On montre que l'estimateur inter-individuel (between) de la relation statique, alors que la vraie spécification est dynamique, converge toujours en probabilité vers les effets de long terme. Par contre, ce résultat ne s'applique pas systématiquement aux estimateurs des MCO et intra-individuel (within). D'autre part, nous mettons en évidence l'importance de l'effet individuel sur la variable explicative dans la convergence plus ou moins rapide des estimateurs between, des MCO et within vers le coefficient de long terme. En particulier, sa présence permet de retrouver l'association entre estimateurs des MCO et between pour retracer les effets de long terme. Enfin, l'estimation d'un modèle de demande de travail sur un panel de 93 entreprises françaises suivies de 1987 à 1991, nous permet de conclure quant à la pertinence empirique de nos résultats théoriques.
Une application des réseaux de neurones artificiels MLP à la prévision du prix d'une option négociable
Authors: Fiordaliso Antonio
Published: August 2011

Une application des réseaux de neurones artificiels MLPà la prévision du prix d'une option négociable

par Antonio Fiordaliso

Le problème étudié est celui de la prévision du prix du call sur contrat à terme Eurodollar 3 mois (ED3). Le but recherché est de mettre au point un modèle de prévision neuronal, qui pourra s'intégrer ultérieurement dans un système expert flou de gestion dynamique de portefeuilles d'options. Nous détaillons quelques problèmes et techniques relatifs à la mise au point des modèles ANN {Artificial Neural Networks) dans le cadre d'une prévision effectuée à partir d'une seule variable explicative, et de plusieurs. L'architecture neuronale considérée est celle du Perceptron multi-couches (MLP). Nous comparons les prévisions neuronales à celles obtenues par d'autres techniques de prévision.
Entreprises et formation continue
Authors: Delame Emmanuel , Kramarz Francis
Published: August 2011

Entreprises et la formation continue par Emmanuel Delame et Francis Kramarz

La loi du 16 juillet 1971 institue la participation des entreprises d'au moins 10 salariés au financement de la formation continue. Si des entreprises (les plus grandes et les plus qualifiées) dépensent plus que le minimum légal ( 1 ,2 % de leur masse salariale en 1 987), d'autres versent cette somme à l'État ou à des organismes spécialisés sans former. Entre deux, il existe des entreprises qui forment en dépensant juste la somme minimale.

Cette étude, réalisée à partir de 495 entreprises industrielles, montre la constance des comportements de formation dans le temps (qui a formé formera, qui n'a formé a peu de chance de le faire un jour). Seules les entreprises très formatrices tirent leur épingle du jeu avec un meilleur profit et une productivité accrue pour le qualifié.
Le Nairu en France : les insuffisances d'une courbe de Phillips
Authors: L'Horty Yannick , Thibault Florence
Published: August 2011

Le Nairu en France : les insuffisances d'une courbe de Phillips par Yannick L'Horty et Florence Thibault

La courbe de Phillips a longtemps été un instrument privilégié pour expliquer le lien entre salaire et chômage. Le niveau du Nairu qui lui est implicite fournit en théorie un guide précieux pour la politique économique permettant d' apprécier l' opportunité respective d'une politique d'offre ou de demande. Cet article rappelle dans un premier temps les fondements donnés à cette relation et ses principaux enjeux. En second lieu, il discute ses insuffisances dans un contexte où le taux de chômage se maintient durablement à un niveau élevé et souligne a contrario les avantages d'une représentation de type courbe de salaire en niveau. À titre d'illustration, une évaluation du Nairu français a été réalisée sur la base d'une boucle prix-salaire standard spécifiée en taux de croissance et sans terme de rappel, c'est-à-dire conformément à la pratique traditionnelle des modélisateurs. Le Nairu ainsi évalué ne présente pas de tendance à la hausse depuis 1970. Combinaison linéaire de variables stationnaires, il est lui-même une variable stationnaire et fluctue autour d'une constante qui correspond par construction au niveau moyen du chômage effectif. On ne dispose donc pas d'une mesure fiable du chômage d'équilibre permettant de satisfaire l'objectif initial de Phillips qui était de fonder l'intervention de politique économique.
Les déterminants du chômage d'équilibre : estimation d'un modèle WS-PS
Authors: L'Horty Yannick , Sobczak Nicolas
Published: August 2011

Les déterminants du chômage d'équilibre : estimation d'un modèle WS-PS par Yannick L'Horty et Nicolas Sobczak

Cette étude propose une évaluation du chômage d'équilibre en France sur la base d'une estimation d'un modèle WS-PS sur données macro-économiques trimestrielles. Dans un premier temps on discute les déterminants théoriques du chômage d'équilibre dans le cadre d'un modèle de négociation salariale avec des spécifications très générales. L'estimation multivariée d'un modèle minimal permet ensuite de mettre en évidence deux relations de cointégration à partir desquelles on identifie les formes structurelles des équations de prix et de salaire. Le socle constitué par le modèle minimal permet enfin d'explorer le rôle de plusieurs variables susceptibles de concourir à la formation du chômage d'équilibre, telles que le coin fiscalo-social, les termes de l'échange, l'indemnisation du chômage, ou le mismatch. Les estimations univariées et multivariées d'un modèle enrichi font ainsi apparaître le rôle déterminant du coin salarial, du ralentissement des gains de productivité, et plus modestement des revenus de remplacement dans la montée du chômage d'équilibre en France.
Asymétries financières et transmission de la politique monétaire en Europe
Authors: Coudert Virginie , Mojon Benoît
Published: August 2011

Asymétries financières et transmission de la politique monétaire en Europe par Virginie Coudert et Benoît Mojon

Dans la perspective d'une politique monétaire unique en Europe, il est essentiel de savoir si une même politique monétaire a un impact similaire sur les économies nationales. Malgré l'utilisation générale du taux d'intérêt comme instrument par les banques centrales, les canaux de transmission de la politique monétaire à la sphère réelle sont multiples. En plus du canal de type ISLM qui transite par la monnaie ou le taux d'intérêt et le canal du taux de change dont l'impact sur les prix et le commerce extérieur sont bien connus, un canal de transmission par le crédit a été récemment mis en avant par une littérature abondante. La dépendance au crédit bancaire de certaines catégories d'agents, les ménages et les PME, introduit un canal de transmission si les banques modifient leur offre de crédit selon la tension de la politique monétaire. L'importance relative de ces différents canaux, dont les effets peuvent être contradictoires, conditionne l'efficacité de la politique monétaire. Or, tout porte à croire que ces canaux de transmission peuvent différer d'un pays à l'autre, voire d'une période à l'autre pour un même pays, parce que l'organisation institutionnelle des systèmes financiers est différente et qu'elle évolue dans le temps.
Une étude comparative des comportements salariaux en Allemagne, en France et aux Pays-Bas
Authors: Loufir Rahim , Malgrange Pierre
Published: August 2011

Une étude comparative des comportements salariaux en Allemagne, en France et aux Pays-Bas "

par Rahim Loufir et Pierre Malgrange

L'objet de ce papier est de comparer de manière descriptive et économétrique l'évolution de la relation de salaire, en données trimestrielles, de l'Allemagne, des Pays-Bas et de la France dans le but de mettre en évidence les spécificités nationales et une éventuelle convergence dans les années récentes. Pour ce dernier aspect, des méthodes récursives (filtre de Kalman) sont mises en œuvre, mais ne semblent pas indiquer d'inflexions structurelles significatives.
Impact de l'annonce de la modalité de fixation des taux de conversion des monnaies européennes
Authors: Rzepkowski Bronka
Published: August 2011

European Currencies Exchange Rates Conversion Rules: Impact of a Prior Announcement

by Bronka Rzepkowski

Conversion rates vis-à-vis the euro will be known only on the first January 1999. This uncertainty on the levels of final parities may be the source of instalibity during the interim period. Such a risk of tensions can be limited a pre-announcement. The impact of three different modalities for setting bilateral conversion rates is examined in two steps : firstly, foreign exchange and interest rates adjustments at the time of the announcement ; secondly, the dynamics of the currency rates during the interim period. Simulations of exchange rate paths show that annoucing a precise rate (central rate) or an average rule would result in similar levels of volatility. However, announcing a target band would entail at least twice more volatility.
Hard beta and gamma emissions of 124I
Authors: Franssen R. , Visser M. G. W. , Urbach C. J. A. , Halders S. G. E. A. , Frantzen M. J. , Brans B. , Teule G. J. J. , Mottaghy F. M. , Kemerink G. J.
Published: August 2011

Aim: The hard beta and gamma radiation of 124I can cause high doses to PET/CT workers. In this study we tried to quantify this occupational exposure and to optimize radioprotection. Methods: Thin MCP-Ns thermoluminescent dosimeters suitable for measuring beta and gamma radiation were used for extremity dosimetry, active personal dosimeters for whole-body dosimetry. Extremity doses were determined during dispensing of 124I and oral administration of the activity to the patient, the body dose during all phases of the PET/CT procedure. In addition, dose rates of vials and syringes as used in clinical practice were measured. The procedure for dispensing 124I was optimized using newly developed shielding. Results: Skin dose rates up to 100 mSv/ min were measured when in contact with the manufacturer's vial containing 370 MBq of 124I. For an unshielded 5 ml syringe the positron skin dose was about seven times the gamma dose. Before optimization of the preparation of 124I, using an already reasonably safe technique, the highest mean skin dose caused by handling 370 MBq was 1.9 mSv (max. 4.4 mSv). After optimization the skin dose was below 0.2 mSv. Conclusion: The highly energetic positrons emitted by 124I can cause high skin doses if radioprotection is poor. Under optimized conditions occupational doses are acceptable. Education of workers is of paramount importance.
Phylogenetics of the Chamaesyce clade (Euphorbia, Euphorbiaceae): Reticulate evolution and long‐distance dispersal in a prominent C4 lineage
Authors: Yang Ya , Berry Paul E.
Published: August 2011

• Premise of the study: The Chamaesyce clade of Euphorbia is the largest lineage of C4 plants among the eudicots, with 350 species including both narrow endemics and cosmopolitan weeds. We sampled this group worldwide to address questions about subclade relationships, the origin of C4 photosynthesis, the evolution of weeds, and the role of hybridization and long‐distance dispersal in the diversification of the group.

• Methods: Two nuclear (ITS and exon 9 of EMB2765) and three chloroplast markers (matK, rpl16, and trnL‐F) were sequenced for 138 ingroup and six outgroup species. Exon 9 of EMB2765 was cloned in accessions with >1% superimposed peaks.

• Key results: The Chamaesyce clade is monophyletic and consists of three major subclades [1(2,3)]: (1) the Acuta clade, containing three North American species with C3 photosynthesis and C3‐C4 intermediates; (2) the Peplis clade, mostly North American and entirely C4; and (3) the Hypericifolia clade, all C4, with both New World and Old World groups. Incongruence between chloroplast and ITS phylogenies and divergent cloned copies of EMB2765 exon 9 suggest extensive hybridization, especially in the Hawaiian Islands radiation.

• Conclusions: The Chamaesyce clade originated in warm, arid areas of North America, where it evolved C4 photosynthesis. From there, it diversified globally with extensive reticulate evolution and frequent long‐distance dispersals. Although many species are weedy, there are numerous local adaptations to specific substrates and regional or island radiations, which have contributed to the great diversity of this group.
Congruence between geographic range distribution and local competitive ability of twoLupinusspecies
Authors: Milla Rubén , Iriondo Adrián EscuderoJosé M.
Published: August 2011

•Premise of the study:In spite of its relevance, we lack rigorous evidence on whether widespread species are superior local competitors compared with coexisting narrowly distributed congeners. We ran a competition experiment between two lupins that coexist at their shared geographic range:Lupinus angustifoliusL. (widespread) andL. gredensisGandoger (narrow endemic).

•Methods:We set up mixed and monospecific populations of the two species, monitored survival and fecundity until the death of the whole cohorts, and measured variables of putative relevance to the competition process. We used aster modeling to address lifetime individual fitness and generalized linear models to assess the effect of species, type of competition, and competition environment on a suite of competition indices.

•Key results:Lupinus angustifoliusshowed higher fitness and exerted a stronger competitive effect on its heterospecific neighbors. This occurred through higher fecundity late in the season rather than through differential survival at earlier stages.

•Conclusions:This is the first evidence of lifetime superior competitive potential of a widespread species over a narrow endemic congener. This competitive response might scale up to the geographic distribution range and may partially explain the limited distribution of the narrow endemic. Extension to other carefully selected study cases and more in‐depth field experiments may help to assess the generality of this pattern and understand how local processes translate into geographic patterns.
Comparative anatomical and developmental analysis of dry and fleshy fruits of Solanaceae
Authors: Pabón‐Mora Natalia , Litt Amy
Published: August 2011

• Premise of the study: An anatomical examination of dry and fleshy fruits within the Solanaceae was carried out to identify comparable stages throughout development as well as features exclusive to each type of fruit. We studied fruit development of Nicotiana and Petunia, which have the plesiomorphic capsular fruit; Solanum and Iochroma, characterized by a derived fleshy berry; Cestrum, an independent origin of a fleshy fruit; and Datura, a reversion to a dry fruit.

• Methods: Pre‐ and postanthesis carpels and fruits of all species were collected, sectioned, stained, and examined using light microscopy.

• Key results: Comparable stages of carpel and fruit development were identified in all species. Furthermore, anatomical and developmental features were identified that characterize capsules in Solanaceae, including lack of increase in the number of pericarp cell layers, formation of a sclerified endocarp, and elongation of the epidermal cells of the placenta. Pericarps of fleshy fruits of the Solanoideae are characterized by abundant collenchyma, an increase in the number of cell layers, and a parenchymatous endocarp often expanding into the locules. Anatomical data show that early developmental stages of the fruit of Cestrum, a berry, are similar to the capsular fruits of Petunia and Nicotiana; similarly, Datura, one of the few capsular members of the Solanoideae, shares several anatomical features with closely related berried taxa.

• Conclusions: Ontogenetically, all fleshy or all dry fruits do not necessarily share a common developmental ground plan. Independent evolution of fleshiness, sclerification, dryness, and dehiscence are discussed in a phylogenetic context.
Microsatellite markers for Dayaoshania cotinifolia (Gesneriaceae), a critically endangered perennial herb
Authors: Zhang Bing , Wang Hong‐Wei , Cheng Yue‐Qin , Ye Yong‐Zhong , Wang Zhao‐Shan
Published: August 2011

• Premise of the study: Microsatellite primers were developed for the critically endangered species Dayaoshania cotinifolia (Gesneriaceae) to evaluate population genetic diversity and detect population history.

• Methods and Results: In our study, 15 primer sets were developed using an enriched genomic library. These are the first microsatellite loci developed for this genus. Genetic diversity was measured using 40 individuals. The number of alleles per locus ranged from one to six, and the incidence of observed heterozygosities was 0.365 and 0.410 in two populations.

• Conclusions: The described markers will be useful in future population genetics studies of this critically endangered species.
Three new teosintes (Zeaspp., Poaceae) from México
Authors: Sánchez G. J. J. , De La Cruz L. L. , Vidal M. V. A. , Ron P. J. , Taba S. , Santacruz‐Ruvalcaba F. , Sood S. , Holland J. B. , Ruíz C. J. A. , Carvajal S. , Aragón C. F. , Chávez T. V. H. , Morales R. M. M. , Barba‐González R.
Published: August 2011

•Premise of the study:Teosinte species are the closest relatives of maize and represent an important but increasingly rare genetic resource for maize improvement and the study of evolution by domestication. Three morphologically and ecologically distinct teosinte populations were recently discovered in México. The taxonomic status of these rare and endangered populations was investigated by detailed comparisons to previously characterized wildZeaspecies.

•Methods:Three new teosinte populations were compared to known teosinte taxa on the basis of morphological, ecogeographic, cytological, and molecular characteristics. Phenetic and phylogenetic analyses were performed using morphological and molecular data, respectively.

•Key results:The newly discovered populations are distinct from each other and from otherZeaspecies to represent three new entities based on their unique combinations of morphological, ecological, ploidy, and DNA markers. A perennial diploid population from Nayarit is distinguished by early maturing plants, and having male inflorescences with few tassel branches and long spikelets. A perennial tetraploid population from Michoacán is characterized by tall and late maturing plants, and having male inflorescences with many branches. An annual diploid population from Oaxaca is characterized by having male inflorescences with fewer branches and longer spikelets than those found in the sister taxaZ. luxuriansandZ. nicaraguensis, plants with high thermal requirements, and very long seed dormancy.

•Conclusions:Evidence from multiple independent sources suggests placement of the three new populations of teosinte as distinct entities within sectionLuxuriantesof the genusZea. However, more extensive DNA marker or sequence data are required to resolve the taxonomy of this genus.
Tip-enhanced Raman spectroscopic imaging of patterned thiol monolayers
Authors: Stadler Johannes , Schmid Thomas , Opilik Lothar , Kuhn Phillip , Dittrich Petra S , Zenobi Renato
Published: August 2011

Full spectroscopic imaging by means of tip-enhanced Raman spectroscopy (TERS) was used to measure the distribution of two isomeric thiols (2-mercaptopyridine (2-PySH) and 4-mercaptopyridine (4-PySH)) in a self-assembled monolayer (SAM) on a gold surface. From a patterned sample created by microcontact printing, an image with full spectral information in every pixel was acquired. The spectroscopic data is in good agreement with the expected molecular distribution on the sample surface due to the microcontact printing process. Using specific marker bands at 1000 cm−1 for 2-PySH and 1100 cm−1 for 4-PySH, both isomers could be localized on the surface and semi-quantitative information was deduced from the band intensities. Even though nanometer size resolution information was not required, the large signal enhancement of TERS was employed here to detect a monolayer coverage of weakly scattering analytes that were not detectable with normal Raman spectroscopy, emphasizing the usefulness of TERS.
Distinguishing between Return to Juvenile versus Adult Prison in Juvenile Recidivism Analyses
Authors: Boulger Jordan K. , Olson David E.
Published: August 2011

Although considerable attention has been paid to the outcomes of adults released from prison, a notable shortcoming of the evolving reentry literature is the minimal inclusion of juveniles in recidivism analyses. Through an examination of administrative data collected by the Illinois Department of Corrections for 1,894 youth released from Illinois Youth Centers (IYC) in 2003, we sought to determine the rate at which juveniles were returned to either an IYC or an adult prison within a six-year follow-up period, and how youth demographic, legal, and social characteristics were predictive of return to prison. The analyses found that approximately 45% of the youth were returned to a juvenile facility within six years, and when admission into an adult prison was included, the recidivism rate increased to 62%. Logistic regression showed some consistencies and differences in the relationship between youth characteristics and return to either a juvenile or adult prison within the follow-up period.
Research-Note: An Examination of the Effect of Black Isolation on White Homicide and Robbery Arrest Rates
Authors: Beaulieu Mark
Published: August 2011

There are two common themes in research that examines the link between segregation and race-specific crime (whether measured by racially disaggregated arrest rates, offending, or victimization). First, the majority of this research focuses on the theoretical link between segregation and black crime. While the research may include race-specific arrest rates from the Uniform Crime Reports or offending/victimization data from the Supplementary Homicide Reports, there is usually no expectation for a relationship between the segregation of the black community and the measure of white crime. Second, the dissimilarity index is the most commonly used measure of segregation in this type of research, as opposed to other measures such as the isolation index. The present study adds to the current literature in two ways. First, it presents a hypothesis that the segregation of African-Americans may benefit the white community by reducing white homicide and robbery arrest rates. Second, it replaces the dissimilarity index with the rarely used isolation index for both methodological and theoretical reasons. Findings from ordinary least squares regression using a sample of 81 of the largest cities from 1990 and 2000 suggest that black isolation lowers both white homicide and white robbery arrest rates.
Le financement des retraites aux États-Unis
Authors: Touzé Vincent
Published: August 2011

Résumé Deux logiques concourent au financement des retraites américaines : un régime fédéral par répartition verse des pensions de base ; des fonds de retraite par capitalisation gérés par des employeurs publics ou privés complètent le système. La récession de 2009 a lourdement pesé sur les ressources du régime par répartition et ce dernier est en déficit primaire depuis 2010. Toutefois son financement n’a pas été mis en péril grâce aux revenus financiers d’un fonds de réserve qui compensent amplement le déficit primaire. La crise a réduit les ressources et rapproché la période où le régime commence à puiser dans le fonds de réserve. À long terme, ce dernier ne sera pas suffisant pour couvrir le déficit chronique. Des réformes seront donc nécessaires d’ici 2030. Avec la crise financière, les régimes par capitalisation ont souffert d’une forte dévalorisation de leurs actifs, ce qui peut poser un problème de survie pour certains fonds de pension. Pour ceux qui versent des pensions à prestation définie, le risque est porté par les employeurs qui doivent alors ajuster leurs contributions en fonction des performances boursières. Pour les pensions à cotisations définies, les aléas financiers sont intégralement supportés par les salariés. En cas de faillite, les fonds de pension à prestation définie du secteur privé bénéficient d’une garantie fédérale. Ce n’est pas le cas pour les fonds gérés par les États et les administrations locales. Pourtant, ces derniers semblent plus vulnérables car ils étaient déjà sous-capitalisés avant la crise et, de plus, leurs engagements auraient été largement sous-évalués. Des mesures correctives nationales ou locales semblent donc inévitables.
Photo Elicitation: Enhancing Learning in the Affective Domain
Authors: Linz Sheila
Published: August 2011

This column offers tips for using photo essays in both traditional and online learning settings.
Evaluation of a Workplace Bullying Cognitive Rehearsal Program in a Hospital Setting
Authors: Stagg Sharon J. , Sheridan Daniel , Jones Ruth Ann , Speroni Karen Gabel
Published: August 2011

Workplace bullying is a serious problem faced by nurses nationally. This study was conducted to determine the frequency of workplace bullying and evaluate the effectiveness of a training program on cognitive rehearsal of responses to common bullying behaviors. This program to increase staff nurses’ knowledge of management of workplace bullying consisted of three components: pilot survey testing, a piloted Internet-based survey administered to the medical and surgical nurses, and a 2-hour cognitive rehearsal training program on management of workplace bullying. The results showed that 80% of the nurses surveyed had experienced workplace bullying over the previous year. After the training program, nurses’ knowledge of workplace bullying management significantly increased. Additionally, nurses were significantly more likely to report that they had observed bullying and had bullied others. Further, nurses felt more adequately prepared to handle workplace bullying. Results of the research support the provision of a workplace bullying management program for nurses and the need for a specific policy on workplace bullying.
Surgical Management of Pediatric Limbal Dermoids With Sutureless Amniotic Membrane Transplantation and Augmentation
Authors: Pirouzian Amir , Holz Huck , Merrill Kevin , Sudesh Rattehalli , Karlen Kris
Published: August 2011

Purpose:

To further evaluate the efficacy of a new surgical technique for removal of pediatric corneal-limbal dermoids and ocular surface reconstruction using multilayered amniotic membrane.

Methods:

Three pediatric patients with corneal-limbal dermoid (grade I) in one practice were identified in a retrospective fashion. All patients underwent deep lamellar excision followed by sutureless multilayered amniotic membrane transplantation by a single surgeon (AP). Preoperative and postoperative visual acuity, anterior segment examination, anterior segment B-scan, and cycloplegic refraction were performed.

Results:

Three patients with ages ranging from 6 months to 18 years had a postoperative follow-up of 9 to 12 months from the time of surgery. This surgical technique achieved rapid postoperative corneal re-epithelialization, reduced postoperative pain, and diminished postoperative scarring in all three patients. Existing preoperative astigmatism remained unchanged throughout the follow-up period. No intraoperative or postoperative complications were noted.

Conclusion:

This surgical approach offers an alternative surgical technique to a simple excision with or without deep lamellar keratoplasty for removal of pediatric corneal-limbal dermoids (grade I). In the management of pediatric limbal dermoids (grade I), surgical excision combined with sutureless multilayered amniotic membrane transplantation eliminates painful postoperative recovery and corneal neovascularization, and can achieve an improved long-term ocular surface cosmesis.
The Potential Cost-Effectiveness of Amblyopia Screening Programs
Authors: Rein David B. , Wittenborn John S. , Zhang Xinzhi , Song Michael , Saaddine Jinan B. ,   the Vision Cost-effectiveness Study Group
Published: August 2011

Purpose:

To estimate the incremental cost-effective-ness of amblyopia screening at preschool and kindergarten, the costs and benefits of three amblyopia screening scenarios were compared to no screening and to each other: (1) acuity/stereopsis (A/S) screening at kindergarten, (2) A/S screening at preschool and kindergarten, and (3) photoscreening at preschool and A/S screening at kindergarten.

Methods:

A probabilistic microsimulation model of amblyopia natural history and response to treatment with screening costs and outcomes estimated from two state programs was programmed. The probability was calculated that no screening and each of the three interventions were most cost-effective per incremental quality-adjusted life year (QALY) gained and case avoided.

Results:

Assuming a minimal 0.01 utility loss from monocular vision loss, no screening was most cost-effective with a willingness to pay (WTP) of less than $16,000 per QALY gained. A/S screening at kindergarten alone was most cost-effective at a WTP between $17,000 and $21,000. A/S screening at preschool and kindergarten was most cost-effective at a WTP between $22,000 and $75,000, and photoscreening at preschool and A/S screening at kindergarten was most cost-effective at a WTP greater than $75,000. Cost-effectiveness substantially improved when assuming a greater utility loss. All scenarios were cost-effective when assuming a WTP of $10,500 per case of amblyopia cured.

Conclusion:

All three screening interventions evaluated are likely to be considered cost-effective relative to many other potential public health programs. The choice of screening option depends on budgetary resources and the value placed on monocular vision loss prevention by funding agencies.
Effect of Femtosecond Laser Cataract Surgery on the Macula
Authors: Ecsedy Mónika , Miháltz Kata , Kovács Illés , Takács Ágnes , Filkorn Tamás , Nagy Zoltán Z.
Published: August 2011

PURPOSE:

To compare the effect of conventional and femtosecond laser–assisted (Alcon LenSx Inc) phacoemulsification on the macula using optical coherence tomography (OCT).

METHODS:

Twenty eyes of 20 patients underwent uneventful cataract surgery in both study groups: femtosecond laser–assisted (laser group) and conventional phacoemulsification (control group). Macular thickness and volume were evaluated by OCT preoperatively and 1 week and 1 month postoperatively. Primary outcomes were OCT retinal thickness in 3 macular areas and total macular volume at 1 week and 1 month postoperative. Secondary outcomes were changes in retinal thickness at 1 week and 1 month postoperatively, with respect to preoperative retinal thickness values and effective phacoemulsification time.

RESULTS:

Multivariable modeling of the effect of surgery on postoperative macular thickness showed significantly lower macular thickness in the inner retinal ring in the laser group after adjusting for age and preoperative thickness across the time course (
P
=.002). In the control group, the inner macular ring was significantly thicker at 1 week (mean: 21.68 μm; 95% confidence limit [CL]: 11.93–31.44 μm,
P
<.001). After 1 month, this difference decreased to a mean of 17.56 μm (95% CL: −3.21–38.32 μm,
P
=.09) and became marginally significant.

CONCLUSIONS:

Results of this study suggest that femtosecond laser–assisted cataract extraction does not differ in postoperative macular thickness as compared with standard ultrasound phacoemulsification.
Macular Detachment for Treatment of Persistent Macular Hole
Authors: Oliver Alejandro , Wojcik E. Joanna
Published: August 2011

The authors report a technique for treatment of persistent macular holes in cases refractory to traditional surgical techniques. With a standard pars plana vitrectomy approach, subretinal infusion of balanced salt solution was performed and followed by a fluid–air exchange. This intervention resulted in hole closure despite poor prognosis and may be considered as a treatment option for patients with persistent flat macular holes.
IL-2 Regulates Expression of C-MAF in Human CD4 T Cells
Authors: Rani Aradhana , Afzali Behdad , Kelly Audrey , Tewolde-Berhan Lemlem , Hackett Mark , Kanhere Aditi S. , Pedroza-Pacheco Isabela , Bowen Holly , Jurcevic Stipo , Jenner Richard G. , Cousins David J. , Ragheb Jack A. , Lavender Paul , John Susan
Published: August 2011

Blockade of IL-2R with humanized anti-CD25 Abs, such as daclizumab, inhibits Th2 responses in human T cells. Recent murine studies have shown that IL-2 also plays a significant role in regulating Th2 cell differentiation by activated STAT5. To explore the role of activated STAT5 in the Th2 differentiation of primary human T cells, we studied the mechanisms underlying IL-2 regulation of C-MAF expression. Chromatin immunoprecipitation studies revealed that IL-2 induced STAT5 binding to specific sites in the C-MAF promoter. These sites corresponded to regions enriched for markers of chromatin architectural features in both resting CD4 and differentiated Th2 cells. Unlike IL-6, IL-2 induced C-MAF expression in CD4 T cells with or without prior TCR stimulation. TCR-induced C-MAF expression was significantly inhibited by treatment with daclizumab or a JAK3 inhibitor, R333. Furthermore, IL-2 and IL-6 synergistically induced C-MAF expression in TCR-activated T cells, suggesting functional cooperation between these cytokines. Finally, both TCR-induced early IL4 mRNA expression and IL-4 cytokine expression in differentiated Th2 cells were significantly inhibited by IL-2R blockade. Thus, our findings demonstrate the importance of IL-2 in Th2 differentiation in human T cells and support the notion that IL-2R–directed therapies may have utility in the treatment of allergic disorders.
Human Natural Regulatory T Cell Development, Suppressive Function, and Postthymic Maturation in a Humanized Mouse Model
Authors: Onoe Takashi , Kalscheuer Hannes , Danzl Nichole , Chittenden Meredith , Zhao Guiling , Yang Yong-Guang , Sykes Megan
Published: August 2011

CD4+ regulatory T cells (Tregs) control adaptive immune responses and promote self-tolerance. Various humanized mouse models have been developed in efforts to reproduce and study a human immune system. However, in models that require T cell differentiation in the recipient murine thymus, only low numbers of T cells populate the peripheral immune systems. T cells are positively selected by mouse MHC and therefore do not function well in an HLA-restricted manner. In contrast, cotransplantation of human fetal thymus/liver and i.v. injection of CD34+ cells from the same donor achieves multilineage human lymphohematopoietic reconstitution, including dendritic cells and formation of secondary lymphoid organs, in NOD/SCID mice. Strong Ag-specific immune responses and homeostatic expansion of human T cells that are dependent on peripheral human APCs occur. We now demonstrate that FOXP3+Helios+ “natural” Tregs develop normally in human fetal thymic grafts and are present in peripheral blood, spleen, and lymph nodes of these humanized mice. Humanized mice exhibit normal reversal of CD45 isoform expression in association with thymic egress, postthymic “naive” to “activated” phenotypic conversion, and suppressive function. These studies demonstrate the utility of this humanized mouse model for the study of human Treg ontogeny, immunobiology and therapy.
Human resource management as a profession in South Africa
Authors: Van Rensburg Huma , Basson Johan S. , Carrim Nasima M.H.
Published: August 2011

Orientation: Various countries recognise human resource (HR) management as a bona fide profession. Research purpose: The objective of this study was to establish whether one could regard HR management, as practised in South Africa, as a profession.Motivation for the study: Many countries are reviewing the professionalisation of HR management. Therefore, it is necessary to establish the professional standing of HR management in South Africa.Research design, approach and method: The researchers used a purposive sampling strategy involving 95 participants. The researchers achieved triangulation by analysing original documents of the regulating bodies of the medical, legal, engineering and accounting professions internationally and locally as well as the regulating bodies of HR management in the United Kingdom (UK), the United States of America (USA) and Canada. Seventy- eight HR professionals registered with the South African Board for People Practices (SABPP) completed a questionnaire. The researchers analysed the data using content analysis and Lawshe’s Content Validity Ratio (CVR).Main findings: The results confirm that HR management in South Africa adheres to the four main pillars of professionalism and is a bona fide profession.Practical/managerial implications: The article highlights the need to regulate and formalise HR management in South Africa.Contribution/value-add: This study identifies a number of aspects that determine professionalism and isolates the most important elements that one needs to consider when regulating the HR profession.