Habit Formation and the Persistence of Monetary Shocks

This paper studies the persistent effects of monetary shocks on output. Previous empirical literature documents this persistence, but standard general equilibrium models with sticky prices fail to generate output responses beyond the duration of nominal contracts. This paper constructs and estimates a general equilibrium model with price rigidities, habit formation, and costly capital adjustment. The model is estimated via Maximum Likelihood using US data on output, the real money stock, and the nominal interest rate. Econometric results suggest that habit formation and adjustment costs to capital play an important role in explaining the output effects of monetary policy. In particular, impulse response analysis indicates that the model generates persistent, hump-shaped output responses to monetary shocks.

Alvar Aalto et l'expression de l'humanisme dans l'espace habité

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Smoking habit profile and health-related quality of life

Resumen tomado de la publicación

Tree Inscriptions: restoring a lost facet of the Graeco-Roman epigraphic habit

This article for the first time considers all extant ancient evidence for the habit of carving inscriptions on tree trunks. It emerges a picture that bears remarkable resemblances to what is known from the habit of graffiti writing (with important addition to that latter field to be derived from the findings), for individual and technical texts.

PCR-based markers diagnostic for spring and winter seasonal growth habit in barley

Toward the ultimate goal of replacing field-based evaluation of seasonal growth habit, we describe the design and validation of a multiplex polymerase chain reaction assay diagnostic for allelic status at the barley (Hordeum vulgare ssp. vulgare L.) vernalization locus, VRN-H1 By assaying for the presence of all known insertion–deletion polymorphisms thought to be responsible for the difference between spring and winter alleles, this assay directly tests for the presence of functional polymorphism at VRN-H1 Four of the nine previously recognized VRN-H1 haplotypes (including both winter alleles) give unique profiles using this assay. The remaining five spring haplotypes share a single profile, indicative of function-altering deletions spanning, or adjacent to, the putative “vernalization critical” region of intron 1. When used in conjunction with a previously published PCR-based assay diagnostic for alleles at VRN-H2, it was possible to predict growth habit in all the 100 contemporary UK spring and winter lines analyzed in this study. This assay is likely to find application in instances when seasonal growth habit needs to be determined without the time and cost of phenotypic assessment and during marker-assisted selection using conventional and multicross population analysis.

Molecular and phenotypic characterization of the alternative seasonal growth habit and flowering time in barley (Hordeum vulgare ssp. vulgare L.)

Barley can be classified into three major agronomic types, based on its seasonal growth habit (SGH): spring, winter and alternative. Winter varieties require exposure to vernalization to promote subsequent flowering and are autumn-sown. Spring varieties proceed to flowering in the absence of vernalization and are sown in the spring. The ‘alternative’ (also known as ‘facultative’) SGH is only loosely defined and can be sown in autumn or spring. Here, we investigate the molecular genetic basis of alternative barley. Analysis of the major barley vernalization (VRN-H1, VRN-H2) and photoperiod (PPD-H1, PPD-H2) response genes in a collection of 386 varieties found alternative SGH to be characterized by specific allelic combinations. Spring varieties possessed spring loci at one or both of the vernalization response loci, combined with long-day non-responsive ppd-H1 alleles and wild-type alleles at the short-day photoperiod response locus, PPD-H2. Winter varieties possessed winter alleles at both vernalization loci, in combination with the mutant ppd-H2 allele conferring delayed flowering under short-day photoperiods. In contrast, all alternative varieties investigated possessed a single spring allele (either at VRN-H1 or at VRN-H2) combined with mutant ppd-H2 alleles. This allelic combination is found only in alternative types and is diagnostic for alternative SGH in the collection studied. Analysis of flowering time under controlled environment found alternative varieties flowered later than spring control lines, with the difference most pronounced under short-day photoperiods. This work provides genetic characterization of the alternative SGH phenotype, allowing precise manipulation of SGH and flowering time within breeding programmes, and provides the molecular tools for classification of all three SGH categories within national variety registration processes.

Using laboratory and field measurements to constrain a single habit shortwave optical parameterization for cirrus

A single habit parameterization for the shortwave optical properties of cirrus is presented. The parameterization utilizes a hollow particle geometry, with stepped internal cavities as identified in laboratory and field studies. This particular habit was chosen as both experimental and theoretical results show that the particle exhibits lower asymmetry parameters when compared to solid crystals of the same aspect ratio. The aspect ratio of the particle was varied as a function of maximum dimension, D, in order to adhere to the same physical relationships assumed in the microphysical scheme in a configuration of the Met Office atmosphere-only global model, concerning particle mass, size and effective density. Single scattering properties were then computed using T-Matrix, Ray Tracing with Diffraction on Facets (RTDF) and Ray Tracing (RT) for small, medium, and large size parameters respectively. The scattering properties were integrated over 28 particle size distributions as used in the microphysical scheme. The fits were then parameterized as simple functions of Ice Water Content (IWC) for 6 shortwave bands. The parameterization was implemented into the GA6 configuration of the Met Office Unified Model along with the current operational long-wave parameterization. The GA6 configuration is used to simulate the annual twenty-year short-wave (SW) fluxes at top-of-atmosphere (TOA) and also the temperature and humidity structure of the atmosphere. The parameterization presented here is compared against the current operational model and a more recent habit mixture model.

November 1994: CD-ROMs, Gopher: Freshman Research Habit; Archives Traveling Exhibit

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Can a habit formation model really explain the Forward Premium Anomaly?

Verdelhan (2009) mostra que desejando-se explicar o comporta- mento do prêmio de risco nos mercados de títulos estrangeiros usando- se o modelo de formação externa de hábitos proposto por Campbell e Cochrane (1999) será necessário especi car o retorno livre de risco de equilíbrio de maneira pró-cíclica. Mostramos que esta especi cação só é possível sobre parâmetros de calibração implausíveis. Ainda no processo de calibração, para a maioria dos parâmetros razoáveis, a razão preço-consumo diverge. Entretanto, adotando a sugestão pro- posta por Verdelhan (2009) - de xar a função sensibilidade (st) no seu valor de steady-state durante a calibração e liberá-la apenas du- rante a simulação dos dados para se garantir taxas livre de risco pró- cíclicas - conseguimos encontrar um valor nito e bem comportado para a razão preço-consumo de equilíbrio e replicar o foward premium anom- aly. Desconsiderando possíveis inconsistências deste procedimento, so- bre retornos livres de risco pró-cíclicos, conforme sugerido por Wachter (2006), o modelo utilizado gera curvas de yields reais decrescentes na maturidade, independentemente do estado da economia - resultado que se opõe à literatura subjacente e aos dados reais sobre yields.

Crime and punishment with habit formation

Moral concepts affect crime supply. This idea is modelled assuming that illegal activities is habit forming. We introduce habits in a intertemporal general equilibrium framework to illegal activities and compare its outcomes with a model without habit formation. The findings are that habit and crime presents a non linear relationship that hinges upon the level of capital and habit formation. It is possible to show that while the effect of habit on crime is negative for low levels o habit formation it becomes positive as habits goes up. Secondly habit reduces the marginal effect of illegal activities return on crime. Finally, the effect of habit on crime depends positively on the amount of capital. This could explain the relationship between size of cities and illegal activity.

Can a habit formation model really explain the forward premium anomaly?

Verdelhan (2009) shows that if one is to explain the foreign exchange forward premium behavior using Campbell and Cochrane (1999)’s habit formation model one must specify it in such a way to generate pro-cyclical short term risk free rates. At the calibration procedure, we show that this is only possible in Campbell and Cochrane’s framework under implausible parameters specifications given that the price-consumption ratio diverges in almost all parameters sets. We, then, adopt Verdelhan’s shortcut of fixing the sensivity function λ(st) at its steady state level to attain a finite value for the price-consumption ratio and release it in the simulation stage to ensure pro-cyclical risk free rates. Beyond the potential inconsistencies that such procedure may generate, as suggested by Wachter (2006), with procyclical risk free rates the model generates a downward sloped real yield curve, which is at odds with the data.

Influence of a Parafunctional Oral Habit on Root Fracture Development After Trauma to an Immature Tooth

Root fractures in immature teeth are rare because the resilience of the alveolar bone is more favorable to the occurrence of luxation. This article reports a case of traumatic injury in an immature permanent tooth that progressed to root fracture, having a parafunctional oral habit as the possible modifying factor of case evolution. A 12-year-old boy presented for treatment complaining of a defective restoration and mild pain on the maxillary right central incisor. The patient had a history of crown fracture in this tooth due to trauma 2 years before. The clinical examination showed healthy gingival tissues and no abnormal tooth mobility, whereas radiographic projections revealed healthy periradicular tissues, incomplete root formation, and no visible root fracture. As pulp necrosis was diagnosed, calcium hydroxide therapy was started for canal disinfection and subsequent obturation. However, after 4 weeks of treatment, a horizontal fracture line was observed radiographically in the root's middle third. The patient denied a new traumatic injury, but revealed the habit of chewing on a pencil. Refraining from the deleterious oral habit was strongly advised, and root canal filling with mineral trioxide aggregate was performed to treat the root fracture. After 4 years of follow-up, the tooth has normal function and no abnormal mobility. Images suggestive of remodeling at the apical end of the coronal segment and replacement resorption of the apical segment are seen radiographically. This case demonstrates the need of following cases of dental trauma and the possible influence of parafunctional oral habits as modifying factors of case progression.

Orthodontic treatment of a midline diastema related to mesiodens and thumb-sucking habit

OBJETIVO: A associação de mesiodens com hábito de sucção digital como fatores etiológicos de diastemas medianos é uma situação clínica incomum e, quando presente, provoca um comprometimento estético e funcional. O objetivo desse trabalho é descrever o caso clínico de um paciente, aos 9 anos de idade, com mordida aberta anterior e um diastema mediano de 9 mm. DESCRIÇÃO do CASO: Após o diagnóstico ortodôntico, a conduta terapêutica foi a exodontia do mesiodens e instalação de uma grade palatina fixa para controle do hábito de sucção digital. em seguida, bráquetes ortodônticos foram colados nos incisivos centrais superiores e o diastema foi fechado possibilitando a irrupção espontânea dos incisivos laterais. Quando adequados níveis de trespasse vertical e horizontal entre os incisivos foi alcançado e o hábito removido, o tratamento foi finalizado. CONCLUSÃO: É importante ressaltar que com o objetivo de alcançar resultados estéticos e funcionais satisfatórios, minimizando sequelas ao desenvolvimento da oclusão deve-se realizar o diagnóstico precoce e intervenção imediata dos diastemas medianos patológicos.

Feeding habit of the Amazon river prawn Macrobrachium amazonicum larvae

To investigate the feeding habit of Macrobrachium amazonicum, three experiments were carried out assessing the stage at which larvae start exogenous feeding, the acceptance of inert food by different larval stages and the ratio between live and inert diet ingested by larvae at each larval stage. In the first experiment, newly hatched larvae were kept in 500-mL beakers and fed from stages I, II or III onward. Larval survival was not affected by the larval stage at which exogenous feeding started, but mean weight gain was lower when food was offered from stage III onward. In the second experiment, 60 larvae from each stage (I to IX) were fasted for 2 h and then fed on inert diet in excess. Only larvae from stage IV onward accepted this inert diet. In the last experiment, newly hatched larvae were stocked in a larviculture tank and fed daily on both Artemia nauplii and inert diet. After 15 min, food content in the digestive tract of individual larvae was analyzed under stereomicroscopy. Larvae in stage I did not feed, while live food was accepted from stage II onward and inert food from stage III onward. Larvae in stages IV, V and VI accepted both foods with no preference, while inert food was predominant in stages VII to IX In conclusion, to feed M amazonicum larvae on Artemia before stage II or on inert diet before stage IV is unnecessary. It increases production costs and may impair water quality. From stages IV to VI, feeding on Artemia and inert diet is probably necessary, while inert diet should be the main food item from stage VII onward. This schedule may optimize feeding management and production costs. (c) 2007 Elsevier B.V. All lights reserved.