Regional disparities and determinants of growth in Mexico

Developing countries such as Mexico, in which profound processes of economic liberalization have taken place over the last few decades, offer fertile terrain for studies of regional disparities. Mexico has experienced a history of polarization between regions, the industrialized north and the underdeveloped south, which have seen their differences widen, exacerbated through recurrent crises and liberalization processes. This paper looks at the convergence process among regions, examining which factors might affect regional growth, tracking the evolution of single units and identifying winners and losers. The evidence shows that northern states, bordering the USA, moved from a condition that might be described as `falling-behind' prior to liberalization to that of a `winner' after that process, while southern states went from the position of `catching-up' to that of `loser'. Regional disparities in human capital would appear to be playing a decisive role in the existence of differences. The author acknowledges comments from Gilles Duranton, Henry Overman, Andrés Rodríguez-Pose, two anonymous referees, and participants in seminars in The London School of Economics and the European University Institute.     

Role of resistance physical exercise in preventing testicular damage caused by chronic ethanol consumption in UChB rats

Ethanol consumption is associated with spermatogenesis damage and testosterone level alterations. Alcohol remains the most commonly used substance among athletes and sports enthusiasts. This study evaluated whether resistance physical exercise can reduce the testicular damage caused by ethanol exposure. A total of 36 ethanol drinking (UChB) rats were divided into four groups: C (control rats), ETOH (ethanol consumption), ETOH + T (ethanol consumption + physical training), and T (group physical training). The physical training component of the T and ETOH + T groups was based on a resistance training model consisting of four sets of 10 jumps, with an increasing overload of 50–70% of the body weight attached to the chest three times per week. Rats in the ETOH and ETOH +T groups received 10% ethanol. At postnatal day 90, the rats were sacrificed. Blood sample was collected for hormonal analysis, and the testicles were weighed and processed for histopathological, morphometric, and immunohistochemical analyses. The ETOH group showed an increase in testosterone levels. The immunohistochemical of androgen receptor and the absolute weight of the testes were higher in the ETOH and ETOH + T groups, while the ETOH animals showed a decreased weight gain index. The number of abnormal seminiferous tubules increased in the ETOH and T groups compared to those in the control group (C); however, the association with treatment (ETOH + T group) prevented this effect and decreased caspase‐3 production. In conclusion, these findings show that the combination of ethanol consumption and resistance physical exercise can prevent testicular damage in adult UChB rats.     

A qualitative and quantitative study of the hepatic pigmented macrophage aggregates during the breeding cycle of Ohrid trout, Salmo letnica Kar. (Teloestei, Salmonidae)

It is well known that factors such as aging and water quality may influence pigmented macrophages (PMacs) in fishes, but it is not established yet if PMacs undergo seasonal and breeding dependent variations. This study explored this caveat and reports qualitative histological and stereological data on liver PMacs from wild female Ohrid trout, Salmo letnica, during the annual breeding cycle. Data showed that a minority of PMacs contained melanin and that the vast majority of them contained only hemosiderin or hemosiderin and lipofuscin/ceroid pigment. It was suggested that this is the normal scenario for the species. One remarkable result was the demonstration of a striking increase, after spawning, of the relative and total volumes of the hepatic macrophages, both parenchyma and stroma located. Because the melano PMacs did not vary, those changes were due to fluctuations in the hemosiderin-laden PMacs. We concluded that Ohrid trout presented a pigment composition in liver macrophages that differed from other fish, including salmonids, where most liver phagocytes essentially display melanin. Our quantitative data support interspecies differences in the amount of liver macrophages and also that after spawning expansion of the macrophage pool is crucial and most likely connected with the needs of liver remodeling (leading to a decrease in hepatic mass). So, we suggested that the hormonal (sex steroidal) constellation influenced the liver macrophage pool. Additionally, we proved that the use of fish liver macrophages for biomonitoring should take into account the considerable natural breeding/seasonal dependent variations that are expected to occur.     

Steam resistant CoLa-mordenite catalysts for the SCR of NOx with CH4

The stabilization of Co-mordenite catalysts through lanthanum exchange is reported here. The effect of exchange order and calcination conditions upon the reduction of NO_x to N₂ at 500 °C was tracked during 400 h on a stream containing NO_x, CH₄, O₂ and 10% H₂O. Both the fresh and used catalysts were characterized through TPR, Raman spectroscopy, FTIR spectroscopy using CO as probe molecule, and XPS. These techniques revealed that the CoLa-mordenite catalysts which were not affected by the severe hydrothermal treatment showed no sign of Co or La migration out of the exchange positions. Instead, those that rapidly deactivated showed the formation of cobalt oxides and, in some cases, the migration of the cations to other exchange positions. The presence of exchanged lanthanum seems to preserve the integrity of the zeolite structure preventing the migration of cobalt ions with the subsequent formation of cobalt oxides which favors the reaction of methane with O₂, thus decreasing N₂ production.     

Viscosity prediction for fatty systems

Viscosity data have been measured as a function of temperature for two pure polyunsaturated fatty compounds (linoleic acid and trilinolein), for two multicomponent fatty systems, for a commercial-grade oleic acid (approximately 80% pure), and for canola oil. The measurements were performed in Cannon Fenske glass capillary kinematic viscometers. The contents of a large data bank, containing viscosity data for saturated, monousaturated, and polyunsaturated pure fatty substances, were correlated by an equation based on the number of carbon atoms and double bonds. By using this equation for pure compounds and the UNIMOD group contribution method for mixtures, the viscosity data for model fatty systems, commercial oleic acid, and canola oil were predicted. The good results obtained in the present work indicate that this approach can be a valuable tool for designing or evaluating chemical process equipment for the oil industry.     

Theoretical study of a membrane reactor for the water gas shift reaction under nonisothermal conditions

A simulation of a membrane reactor for the water gas shift reaction is carried out by means of a 1D pseudo‐homogeneous nonisothermal mathematical model. The composite membrane consists of a dense layer of Pd (selective to H₂) supported over a porous ceramic layer. The effect of temperature, overall heat‐transfer coefficient, and mode of operation on the membrane reactor performance and stability are analyzed, and the results obtained are compared with those corresponding to a reactor with no hydrogen permeation. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

Candida rugosa Lipase Supported on High Crystallinity Chitosan as Biocatalyst for the Synthesis of 1-Butyl Oleate

Lipase from Candida rugosa was immobilized onto chitosan using four different protocols. The variation of crystallinity (5.57–92.86%), which was a result of thermal treatments and crosslinking of the chitosan, influenced the protein load (7.46–25.15 mg g^?1 chitosan) and protein load efficiency (21.67–41.68%) for immobilization assays made with identical lipase solution concentration (1.3 mg of protein/mL). The effects of protein load (10, 30, 50 and 70 mg of lipase), reaction temperature (30, 40, 50, 60, 70 °C) and substrates molar ratio (0.05–0.30 M) have been studied in the butyl oleate synthesis in iso-octane when water activity of the free and immobilized enzymes were fixed around 0.53 ± 0.04. The catalytic activity of the immobilized lipase has also been tested. The Ping–Pong bi–bi mechanism with dead end complex of n-butanol was found to fit the initial rate data. The values of the apparent kinetic parameters were determined by graphic and parametric method as: V _max = 18.2–19.0 mmol min^?1 g^?1; K _{M; Acid} = 0.599–0.640 mol L^?1; K _{M; Alcohol} = 0.128–0.149 mol L^?1; and K _{i; Alcohol} = 1.933 mol L^?1.     

A replicated investigation of nitroxide‐mediated radical polymerization of styrene over a range of reaction conditions

A comprehensive experimental investigation of nitroxide‐mediated radical polymerization (NMRP) of styrene using 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO) as controller is presented. Polymerizations with a bimolecular initiator (benzoyl peroxide; BPO) were carried out at 120 and 130°C, with TEMPO/BPO molar ratios ranging from 0.9 to 1.5. Results indicate that increasing temperature increases the rate of polymerization while the decrease in molecular weights is only slight. It was also observed that increasing the ratio of TEMPO/BPO decreased both the rate of polymerization and molecular weights. Probably for the first time in the history of such investigations, the paper contains a comprehensive database, appropriate for parameter estimation in aid of future modelling studies, since it comes from a systematic data collection containing independent replication.