Income taxation with habit formation and consumption externalities

We analyze the dynamic behavior and the welfare properties of the equilibrium path of a growth model where both habits and consumption externalities affect the utility of consumers. We discuss the effects of flat rate income taxes and characterize the optimal income taxation policy. We show that, when consumption externalities and habit adjusted consumption are not perfect substitutes, a counter-cyclical income tax rate allows the competitive equilibrium to replicate the efficient path. Our analysis highlights the crucial role played by complementarities between externalities and habits in order to generate an inefficient dynamic equilibrium.

Spillover effects of public capital formation: evidence from the spanish regions

Maybe because of the inconclusive nature of the results on the impact of public capital on output at the regional level, the issue of the possible existence of the regional spillovers from public capital formation has received little attention. The objective of this paper is to provide evidence on the possible existence of such spillovers. We consider the case of Spain and its seventeen regions. Our methodological approach consists in estimating an aggregate VAR model for Spain as well as seventeen region-specific VAR models in which both capital installed in the region and capital installed outside the region are allowed to play a role in enhancing regional output. The estimation results can be summarized as follows. The aggregate effects of public capital formation in Spain are important. They cannot, however, be captured in their entirety by the direct effects in each region from public capital installed in the region itself. When for each region both the capital installed in the region and the capital installed outside the region are considered the total disaggregated effect from the seventeen regional models are very much in line with the aggregate results. Furthermore, the aggregate effect seems to be due in almost equal parts to the direct and spillover effects of public capital formation. Ultimately, this paper establishes the relevance of both capital installed in each region and spillover effects in the understanding of the regional decomposition of the aggregate effects of public capital formation. In doing so it opens the door to some tantalizing and potentially highly charged research issues in terms of the determination of the optimal location of public investment projects.

New business formation and employment growth: some evidence for the Spanish manufacturing industry

This paper explores the effects of new business formation on employment growth in Spanish manufacturing industries. New firms are believed to make an important contribution to economic growth but the extent of this contribution is unclear. We consider time lags of new firm formation as explanatory variables of employment change and identify how long the effect of new firm entries on employment lasts. Our main results show that the effects of new business formation are positive in the short term, negative in the medium term and positive in the long term, thus confirming the existence of indirect supply-side effects found in similar studies for other countries. Key words: regional growth, firm entry, time lags and Spanish economy. JEL classifications: L00, L60, R11, R12

Studies on Trypanosoma rangeli Tejera, 1920: V - Developmental pattern in the alimentary canal of Rhodnius prolixus

The morphological sequence of Trypanosoma rangeli development in the alimentary canal of Rhodnius prolixus, is described, with observation made in dissected guts from 6 hours to 45 days post-infection. No metacyclic-forms are produced in the digestive tract at any time, and transmission by the contaminative route must be considered atypical. Amastigotes appear to be an essential stage in the development of T. rangeli in the gut of R. prolixus. The epidemiological importance of the developmental pattern of T. rangeli in the vector´s gut is discussed, and its usefulness for aging infection is considered.

Studies on Trypanosoma rangeli Tejera 1920: VI. Developmental pattern in the haemolymph of Rhodnius prolixus

The morphological sequence of Trypanosoma rangeli development in the body cavity of Rhodnius prolixus is described. The metacyclic trypanosome is the product of successive division and transformation during the intra and extracellular development in the haemocoele. The significance of the early invasion of T. rangeli into the haemolymph is discussed. The epidemiological importance of the developmental pattern of T. rangeli in the vectors haemolymph and the host-response to the parasite are considered.

The changing pattern of pathology due to Schistosoma mansoni infection

A survey of the autopsy data on hepatosplenic schistosomiasis during periods, before and after the advent of new chemotherapeutic drugs, revealed that: a) the pathological presentation was the same for the two periods; b) the number of cases in the last five years is progressively decreasing; c) hepatosplenic disease due to schistosomiasis is becoming rare in young people. These data represent a change in the pattern of pathology in schistosomiasis, probably related to new chemotherapy.

Glucose-dependent insulinotropic polypeptide receptor deficiency leads to modifications of trabecular bone volume and quality in mice.

A role for the gastro-intestinal tract in controlling bone remodeling is suspected since serum levels of bone remodeling markers are affected rapidly after a meal. Glucose-dependent insulinotropic polypeptide (GIP) represents a suitable candidate in mediating this effect. The aim of the present study was to investigate the effect of total inhibition of GIP signaling on trabecular bone volume, microarchitecture and quality. We used GIP receptor (GIPR) knockout mice and investigated trabecular bone volume and microarchitecture by microCT and histomorphometry. GIPR-deficient animals at 16 weeks of age presented with a significant (20%) increase in trabecular bone mass accompanied by an increase (17%) in trabecular number. In addition, the number of osteoclasts and bone formation rate was significantly reduced and augmented, respectively in these animals when compared with wild-type littermates. These modifications of trabecular bone microarchitecture are linked to a remodeling in the expression pattern of adipokines in the GIPR-deficient mice. On the other hand, despite significant enhancement in bone volume, intrinsic mechanical properties of the bone matrix was reduced as well as the distribution of bone mineral density and the ratio of mature/immature collagen cross-links. Taken together, these results indicate an increase in trabecular bone volume in GIPR KO animals associated with a reduction in bone quality.

New FFT/IFFT Factorizations with Regular Interconnection Pattern Stage-to-Stage Subblocks

Les factoritzacions de la FFT (Fast Fourier Transform) que presenten un patró d’interconnexió regular entre factors o etapes son conegudes com algorismes paral·lels, o algorismes de Pease, ja que foren originalment proposats per Pease. En aquesta contribució s’han desenvolupat noves factoritzacions amb blocs que presenten el patró d’interconnexió regular de Pease. S’ha mostrat com aquests blocs poden ser obtinguts a una escala prèviament seleccionada. Les noves factoritzacions per ambdues FFT i IFFT (Inverse FFT) tenen dues classes de factors: uns pocs factors del tipus Cooley-Tukey i els nous factors que proporcionen la mateix patró d’interconnexió de Pease en blocs. Per a una factorització donada, els blocs comparteixen dimensions, el patró d’interconnexió etapa a etapa i a més cada un d’ells pot ser calculat independentment dels altres.

Patterns of oxygen consumption during establishment of cephalocaudal polarity in the early chick embryo.

Oxygen uptake was studied during the establishment of cephalocaudal polarity in the very early chick embryo, i.e., 10 hr before (stage VI) and at laying (stage X). Oxygen fluxes in minute regions of the intact blastoderms were measured in vitro by scanning microspectrophotometry in the presence or absence of glucose. The oxygen consumption of the whole blastoderm remained constant (6 nmol O2 X hr-1) throughout the period studied, although the number of cells increased more than twofold. The regional oxygen fluxes varied from 0.41 to 1.13 nmol O2 X hr-1 X mm-2 at stage VI and from 0.42 to 0.70 nmol O2 X hr-1 X mm-2 at stage X. At stage VI, the oxygen flux in the center of the blastoderm was significantly higher than that in its periphery. This pattern remained evident when the values were corrected for cell number or for cytoplasmic volume. At stage X, there was a tendency for the oxygen fluxes to decrease from the posterior to the anterior regions of the area pellucida. Thus the pattern of oxidative metabolism in the late uterine embryos seems to change from radial to bilateral. This change of symmetry probably reflects the process of formation of the embryonic axis. In addition, the fact that the oxygen uptake was similar in the presence or absence of glucose suggests that early chick embryos metabolize essentially intracellular stores.

Granulomatous hypersensitivity to Schistosoma mansoni egg antigens in human Schistosomiasis: I. Granuloma formation and modulation around polyacrylamide antigen-conjugated beads

We have developed an in vitro model of granuloma formation for the purpose of studying the immunological components of delayed type hypersensitivity granuloma formation in patients infected with Schistosoma mansoni. Our data show that 1) granulomatous hypersensitivity can be studied by examining the cellular reactivity manifested as multiple cell layers surrounding the antigen conjugated beads; 2) this reactivity is a CD4 cell dependent, macrophage dependent, B cell independent response and 3) the in vitro granuloma response is antigenically specific for parasite egg antigens. Studies designed to investigate the immune regulation of granulomatous hypersensitivity using purified populations of either CD4 or CD8 T cells have demonstrated the complexity of cellular interactions in the suppression of granulomatous hypersensitivity. The anti-S. mansoni egg immune responses of individual patients with chronic intestinal schistosomiasis can be classified either as soluble egg antigen (SEA) hypersensitive with maximal granulomatous hypersensitivity or SEA suppressive with activation of the T cell suppressor pathway with effective SEA granuloma modulation. Our data suggest that T cell network interactions are active in the generation of effective granuloma modulation in chronic intestinal schistosomiasis patients.

Effects of the naturally occurring food mycotoxin ochratoxin A on brain cells in culture.

The potential of ochratoxin A (OTA) to damage brain cells was studied by using a three-dimensional cell culture system as model for the developing brain. Aggregating cell cultures of foetal rat telencephalon were tested either during an early developmental period, or during a phase of advanced maturation, over a wide range of OTA concentrations (0.4 nM to 50 microM). By monitoring changes in activities of cell type-specific enzymes (ChAt and GAD, for cholinergic and GABAergic neurones, respectively, GS for astrocytes and CNP for oligodendrocytes), the concentration-dependent toxicity and neurodevelopmental effects of OTA were determined. OTA proved to be highly toxic, since a 10-day treatment at 50 nM caused a general cytotoxicity in both mature and immature cultures. At 10 nM of OTA, cell type-specific effects were observed: in immature cultures, a loss in neuronal and oligodendroglial enzyme activities, and an increase in the activity of the astroglial marker glutamine synthetase were found, Furthermore, at 2 and 10 nM of OTA, a clustering of microglial cells was observed. In mature cultures, OTA was somewhat less potent, but caused a similar pattern of toxic effects. A 24 h-treatment with OTA resulted in a concentration-dependent decrease in protein synthesis, with IC50 values of 25 nM and 33 nM for immature and mature cultures respectively. Acute (24 h) treatment at high OTA concentrations (10 to 50 microM) caused a significant increase in reactive oxygen species formation, as measured by the intracellular oxidation of 2',7'-dichlorofluorescin. These results suggest that OTA has the potential to be a potent toxicant to brain cells, and that its effects at nanomolar concentrations are primarily due to the inhibition of protein synthesis, whereas ROS seem not to be involved in the toxicity mediated by a chronic exposure to OTA at such low concentrations.

Colonialism, Elite Formation and Corruption

This paper argues that corruption in developing countries has deep historical roots; going all the way back to the characteristics of their colonial experience. The degree of European settlement during colonial times is used to dfferentiate between types of colonial experience, and is found to be a powerful explanatory factor of present-day corruption levels. The relationship is non-linear, as higher levels of European settlement resulted in more powerful elites (and more corruption) only as long as Europeans remained a minority group in the total population.