Inflammation-driven bone formation in a mouse model of ankylosing spondylitis: Sequential not parallel processes

Background Ankylosing spondylitis (AS) is an immune-mediated arthritis particularly targeting the spine and pelvis and is characterised by inflammation, osteoproliferation and frequently ankylosis. Current treatments that predominately target inflammatory pathways have disappointing efficacy in slowing disease progression. Thus, a better understanding of the causal association and pathological progression from inflammation to bone formation, particularly whether inflammation directly initiates osteoproliferation, is required. Methods The proteoglycan-induced spondylitis (PGISp) mouse model of AS was used to histopathologically map the progressive axial disease events, assess molecular changes during disease progression and define disease progression using unbiased clustering of semi-quantitative histology. PGISp mice were followed over a 24-week time course. Spinal disease was assessed using a novel semi-quantitative histological scoring system that independently evaluated the breadth of pathological features associated with PGISp axial disease, including inflammation, joint destruction and excessive tissue formation (osteoproliferation). Matrix components were identified using immunohistochemistry. Results Disease initiated with inflammation at the periphery of the intervertebral disc (IVD) adjacent to the longitudinal ligament, reminiscent of enthesitis, and was associated with upregulated tumor necrosis factor and metalloproteinases. After a lag phase, established inflammation was temporospatially associated with destruction of IVDs, cartilage and bone. At later time points, advanced disease was characterised by substantially reduced inflammation, excessive tissue formation and ectopic chondrocyte expansion. These distinct features differentiated affected mice into early, intermediate and advanced disease stages. Excessive tissue formation was observed in vertebral joints only if the IVD was destroyed as a consequence of the early inflammation. Ectopic excessive tissue was predominantly chondroidal with chondrocyte-like cells embedded within collagen type II- and X-rich matrix. This corresponded with upregulation of mRNA for cartilage markers Col2a1, sox9 and Comp. Osteophytes, though infrequent, were more prevalent in later disease. Conclusions The inflammation-driven IVD destruction was shown to be a prerequisite for axial disease progression to osteoproliferation in the PGISp mouse. Osteoproliferation led to vertebral body deformity and fusion but was never seen concurrent with persistent inflammation, suggesting a sequential process. The findings support that early intervention with anti-inflammatory therapies will be needed to limit destructive processes and consequently prevent progression of AS.

Long-term outcomes of esophageal atresia

Esophageal atresia (EA), a common congenital anomaly comprising interrupted esophagus with or without a tracheoesophageal fistula (TEF), affects one in 2840 newborns. Over half have associated anomalies. After EA repair in infancy, gastroesophageal reflux (GER) and esophageal dysmotility and respiratory problems are common. As there exist no previous population-based long-term follow-up-studies on EA, its long-term sequelae are unclear. The aims of this study were to assess the cancer incidence (I), esophageal morbidity and function (II), respiratory morbidity (III), and the spinal defects (IV) in adults with repaired EA. All patients treated for EA at the Hospital for Children and Adolescents, University of Helsinki, from 1947 to 1985 were identified, and those alive with their native esophagus were contacted, and the first hundred who replied made up the study group. The patients were interviewed, they filled in symptom questionnaires, and they underwent esophageal endoscopy and manometry, pulmonary function tests, and a full orthopedic evaluation was performed with radiographs of the spine. The questionnaire was also sent by mail to adults with repaired EA not attending the clinical study, and to 287 general population-derived controls matched for age, gender, and municipality of residence. Incidence of cancer among the study population was evaluated from the population-based countrywide cancer registry. 169 (72%) adults with repaired EA replied; 101 (42%) (58 male) participated in the clinical studies at a median age of 36 years (range, 22-56). Symptomatic GER occurred in 34% and dysphagia in 85% of the patients and in 8% and 2% of the controls (P<0.001 for both). The main endoscopic findings included hiatal hernia (28%), Barrett´s esophagus (11%), esophagitis (8%), and stenotic anastomosis (8%). Histology revealed esophagitis in 25 individuals, and epithelial metaplasia in another 21. At immunohistochemistry, CDX2-positive columnar epithelial metaplasia was present in all 21 individuals, and 6 of these also demonstrated goblet cells and MUC2 positivity. In all histological groups, GER and dysphagia were equally common (P=ns). Esophageal manometry demonstrated non-propagating peristalsis in most of the patients, and low ineffective pressure of the distal esophageal body in all. The changes were significantly worse in those with epithelial metaplasia (P≤0.022). Anastomotic complications (OR 8.6-24, 95%CI 1.7-260, P=0.011-0.008), age (OR 20, 95%CI 1.3-310, P=0.034), low distal esophageal body pressure (OR 2.6, 95%CI 0.7-10, P=0.002), and defective esophageal peristalsis (OR 2.2, 95%CI 0.4-11, P=0.014) all predicted development of epithelial metaplasia. Despite the high incidence of esophageal metaplasia, none of the EA patients had suffered esophageal cancer, according to the Finnish Cancer Registry. Although three had had cancer (SIR, 1.0; 95% CI, 0.20-2.8). The overall cancer incidence among adults with repaired EA did not differ from that of the general Finnish population. Current respiratory symptoms occurred in 11% of the patients and 2% of the controls (P<0.001). Of the patients, 16%, and 6% of the controls had doctor-diagnosed asthma (P<0.001). A total of 56% and 70% of the patients and 20% and 50% of the controls had a history of pneumonia and of bronchitis (P<0.001 for both). Respiratory-related impaired quality of life was observable in 11% of the patients in contrast to 6% of the controls (P<0.001). PFT revealed obstruction in 21 of the patients, restriction in 21, and both in 36. A total of 41 had bronchial hyper-responsiveness (BHR) in HCT, and 15 others had an asthma-like response. Thoracotomy-induced rib fusion (OR 3.4, 95%CI 1.3-8.7, P=0.01) and GER-associated epithelial metaplasia in adulthood (OR 3.0, 95%CI 1.0-8.9, P=0.05) were the most significant risk factors for restrictive ventilatory defect. Vertebral anomalies were evident in 45 patients, predominating in the cervical spine in 38. The most significant risk factor for the occurrence of vertebral anomalies was any additional anomaly (OR 27, 95%C I8-100). Scoliosis (over 10 degrees) was observable in 56 patients, over 20 degrees in 11, and over 45 degrees in one. In the EA patients, risk for scoliosis over 10 degrees was 13-fold (OR 13, 95%CI 8.3-21) and over 20 degrees, 38-fold (OR 38, 95%CI 14-106) when compared to that of the general population. Thoracotomy-induced rib fusion (OR 3.6, 95%CI 0.7-19) and other associated anomalies (OR 2.1, 95%CI 0.9-2.9) were the strongest predictive factors for scoliosis. Significant esophageal morbidity associated with EA extends into adulthood. No association existed between the esophageal symptoms and histological findings. Surgical complications, increasing age, and impaired esophageal motility predicted development of epithelial metaplasia after repair of EA. According to our data, the risk for esophageal cancer is less than 500-fold that of the general population. However, the overall cancer incidence among adults with repaired EA did not differ from that of the general population. Adults with repaired EA have had significantly more respiratory symptoms and infections, as well as more asthma, and allergies than does the general population. Thoracotomy-induced rib fusion and GER-associated columnar epithelial metaplasia were the most significant risk factors for the restrictive ventilatory defect that occurred in over half the patients. Over half the patients with repaired EA are likely to develop scoliosis. Risk for scoliosis is 13-fold after repair of EA in relation to that of the general population. Nearly half the patients had vertebral anomalies. Most of these deformities were diagnosed neither in infancy nor during growth. The natural history of spinal deformities seems, however, rather benign, with spinal surgery rarely indicated.

Bone Health in Children and Adolescents with Juvenile Idiopathic Arthritis and Solid Organ Transplant

Osteoporosis is a skeletal disorder characterized by compromised bone strength that predisposes to increased fracture risk. Childhood and adolescence are critical periods for bone mass gain. Peak bone mass is mostly acquired by the age of 18 years and is an important determinant of adult bone health and lifetime risk for fractures. Medications, especially glucocorticoids (GCs), chronic inflammation, decreased physical activity, hormonal deficiencies, delayed puberty, and poor nutrition may predispose children and adolescents with a chronic disease to impaired bone health. In this work, we studied overall bone health, the incidence and prevalence of fractures in children and adolescents who were treated for juvenile idiopathic arthritis (JIA) or had undergone solid organ transplantation. The first study cohort included 62 patients diagnosed with JIA and treated with GCs. The epidemiology of fractures after transplantation was investigated in 196 patients and a more detailed analysis of bone health determinants was performed on 40 liver (LTx) and 106 renal (RTx) transplantation patients. Bone mineral density (BMD) and vertebral morphology were assessed by dual-energy x-ray absorptiometry. Standard radiographs were obtained to detect vertebral fractures and to determine bone age; BMD values were adjusted for skeletal maturity. Our study showed that median BMD values were subnormal in all patient cohorts. The values were highest in patients with JIA and lowest in patients with LTx. Age at transplantation influenced BMD values in LTx but not RTx patients; BMD values were higher in patients who had LTx before the age of two years. BMD was lowest during the immediate posttransplantation years and increased subnormally during puberty. Delayed skeletal maturation was common in all patient groups. The prevalence of vertebral fractures ranged from 10% to 19% in the cohorts. Most of the fractures were asymptomatic and diagnosed only at screening. Vertebral fractures were most common in LTx patients. Vitamin D deficiency was common in all patient groups, and only 3% of patients with JIA and 25% of transplantation patients were considered to have adequate serum vitamin D levels. The total cumulative weight-adjusted dose of GC was not associated with BMD values in JIA or LTx patients. The combination of female gender and age over 15 years, parathyroid hormone concentration over 100 ng/L, and cumulative weight-adjusted methylprednisolone dose over 150 mg/kg during the three preceding years were found to be important predictors for low lumbar spine BMD in RTx patients. Based on the high prevalence of osteoporosis in the study cohorts more efforts should be put to prevention and early diagnosis of osteoporosis in these pediatric patients.

Shwachman-Diamond syndrome : Clinical, genetic and radiological study

Shwachman-Diamond syndrome (SDS) is a rare autosomal recessive disorder in which the cardinal symptoms arise from exocrine pancreatic insufficiency and bone marrow dysfunction. Previous studies have suggested increased risk of fatal complications among Finnish SDS infants. The genetic defect responsible for the disease was recently identified; the SBDS gene is located at chromosome 7q11 and encodes a protein that is involved in ribosome biosynthesis. The discovery of the SBDS gene has opened new insights into the pathogenesis of this multi-organ disease. This study aimed to assess phenotypic and genotypic features of Finnish patients with SDS. Seventeen Finnish patients with a clinical diagnosis of SDS were included in the study cohort. Extensive clinical, biochemical and imaging assessments were performed to elucidate the phenotypic features, and the findings were correlated with the SBDS genotype. Imaging studies included abdominal magnetic reso-nance imaging (MRI), brain MRI, cardiac echocardiography including tissue Doppler examination, and cardiac MRI. The skeletal phenotype was assessed by dual-energy X-ray absorptiometry and bone histomorphometry. Twelve patients had mutations in the SBDS gene. In MRI, a characteristic pattern of fat-replaced pancreas with occasional enhancement of scattered parenchymal foci and of pancreatic duct was noted in the SBDS mutation-positive patients while the mutation-negative patients did not have pancreatic fat accumulation. The patients with SBDS mutations had significantly reduced bone mineral density associated with low-energy peripheral fractures and vertebral compression fractures. Bone histomorphometry confirmed low-turnover osteoporosis. The patients with SBDS mutations had learning difficulties and smaller head size and brain volume than control subjects. Corpus callosum, cerebellar vermis, and pos-terior fossa structures were significantly smaller in SDS patients than in controls. Patients with SDS did not have evidence of clinical heart disease or myocardial fibrosis. However, subtle diastolic changes in the right ventricle and exercise-induced changes in the left ventricle contractile reserve were observed. This study expanded the phenotypic features of SDS to include primary low-turnover osteoporosis and structural alterations in the brain. Pancreatic MRI showed characteristic changes in the SBDS mutation-positive patients while these were absent in the mutation-negative patients, suggesting that MRI can be used to differentiate patients harbouring SBDS mutations from those without mutations. No evidence for clinical cardiac manifestations was found, but imaging studies revealed slightly altered myocardial function that may have clinical implications. These findings confirm the pleiotropic nature of SDS and underscore the importance of careful multidisciplinary follow-up of the affected individuals.

Neck length and mean arterial pressure in the sauropod dinosaurs

How blood was able to reach the heads of the long-necked sauropod dinosaurs has long been a matter of debate and several hypotheses have been presented. For example, it has been proposed that sauropods had exceptionally large hearts, multiple ‘normal’ sized hearts spaced at regular intervals up the neck or held their necks horizontal, or that the siphon effect was in operation. By means of an experimental model, we demonstrate that the siphon principle is able to explain how blood was able to adequately perfuse the sauropod brain. The return venous circulation may have been protected from complete collapse by a structure akin to the vertebral venous plexus. We derive an equation relating neck height and mean arterial pressure, which indicates that with a mean arterial pressure similar to that of the giraffe, the maximum safe vertical distance between heart and head would have been about 12 m. A hypothesis is presented that the maximum neck length in the fossil record is due to the siphon height limit. The equation indicates that to migrate over high ground, sauropods would have had to either significantly increase their mean arterial pressure or keep their necks below a certain height dependent on altitude.

Bone health and vitamin D status in children with motor disability and adults with intellectual disability

Osteoporosis is not only a disease of the elderly, but is increasingly diagnosed in chronically ill children. Children with severe motor disabilities, such as cerebral palsy (CP), have many risk factors for osteoporosis. Adults with intellectual disability (ID) are also prone to low bone mineral density (BMD) and increased fractures. This study was carried out to identify risk factors for low BMD and osteoporosis in children with severe motor disability and in adults with ID. In this study 59 children with severe motor disability, ranging in age from 5 to 16 years were evaluated. Lumbar spine BMD was measured with dual-energy x-ray absorptiometry. BMD values were corrected for bone size by calculating bone mineral apparent density (BMAD), and for bone age. The values were transformed into Z-scores by comparison with normative data. Spinal radiographs were assessed for vertebral morphology. Blood samples were obtained for biochemical parameters. Parents were requested to keep a food diary for three days. The median daily energy and nutrient intakes were calculated. Fractures were common; 17% of the children had sustained peripheral fractures and 25% had compression fractures. BMD was low in children; the median spinal BMAD Z-score was -1.0 (range -5.0 – +2.0) and the BMAD Z-score <-2.0 in 20% of the children. Low BMAD Z-score and hypercalciuria were significant risk factors for fractures. In children with motor disability, calcium intakes were sufficient, while total energy and vitamin D intakes were not. In the vitamin D intervention studies, 44 children and adolescents with severe motor disability and 138 adults with ID were studied. After baseline blood samples, the children were divided into two groups; those in the treatment group received 1000 IU peroral vitamin D3 five days a week for 10 weeks, and subjects in the control group continued with their normal diet. Adults with ID were allocated to receive either 800 IU peroral vitamin D3 daily for six months or a single intramuscular injection of 150 000 IU D3. Blood samples were obtained at baseline and after treatment. Serum concentrations of 25-OH-vitamin D (S-25-OHD) were low in all subgroups before vitamin D intervention: in almost 60% of children and in 77% of adults the S-25-OHD concentration was below 50 nmol/L, indicating vitamin D insufficiency. After vitamin D intervention, 19% of children and 42% adults who received vitamin D perorally and 12% of adults who received vitamin D intramuscularly had optimal S-25-OHD (>80 nmol/L). This study demonstrated that low BMD and peripheral and spinal fractures are common in children with severe motor disabilities. Vitamin D status was suboptimal in the majority of children with motor disability and adults with ID. Vitamin D insufficiency can be corrected with vitamin D supplements; the peroral dose should be at least 800 IU per day.

Modulation of growth by aromatase inhibitor treatment in boys: Efficacy and safety

Without estrogen action, the fusion of the growth plates is postponed and statural growth continues for an exceptionally long time. Aromatase inhibitors, blockers of estrogen biosynthesis, have therefore emerged as a new potential option for the treatment of children with short stature. We investigated the efficacy of the aromatase inhibitor letrozole in the treatment of boys with idiopathic short stature (ISS) using a randomised, placebo-controlled, double-blind research setting. A total of 30 boys completed the two-year treatment. By decreasing estrogen-mediated central negative feedback, letrozole increased gonadotrophin and testosterone secretion in pubertal boys, whereas the pubertal increase in IGF-I was inhibited. Treatment with letrozole effectively delayed bone maturation and increased predicted adult height by 5.9 cm (P0.001), while placebo had no effect on either parameter. The effect of letrozole treatment on near-final height was studied in another population, in boys with constitutional delay of puberty, who received letrozole (n=9) or placebo (n=8) for one year, in combination with low-dose testosterone for six months during adolescence. The mean near-final height of boys randomised to receive testosterone and letrozole was significantly greater than that of boys who received testosterone and placebo (175.8 vs. 169.1 cm, P=0.04). As regards safety, treatment effects on bone health, lipid metabolism, insulin sensitivity, and body composition were monitored in boys with ISS. During treatment, no differences in bone mass accrual were evident between the treatment groups, as evaluated by dual-energy x-ray absorptiometry measurements of the lumbar spine and femoral neck. Bone turnover and cortical bone growth, however, were affected by letrozole treatment. As indicated by differences in markers of bone resorption (U-INTP) and formation (S-PINP and S-ALP), the long-term rate of bone turnover was lower in letrozole-treated boys, despite their more rapid advancement in puberty. Letrozole stimulated cortical bone growth in those who progressed in puberty: the metacarpal index (MCI), a measure of cortical bone thickness, increased more in letrozole-treated pubertal boys than in placebo-treated pubertal boys (25% vs. 9%, P=0.007). The change in MCI correlated positively with the mean testosterone-to-estradiol ratio. In post-treatment radiographic evaluation of the spine, a high rate of vertebral deformities - mild anterior wedging and mild compression deformities - were found in both placebo and letrozole groups. In pubertal boys with ISS treated with letrozole, stimulated testosterone secretion was associated with a decrease in the percentage of fat mass and in HDL-cholesterol, while LDL-cholesterol and triglycerides remained unchanged. Insulin sensitivity, as evaluated by HOMA-IR, was not significantly affected by the treatment. In summary, treatment with the aromatase inhibitor letrozole effectively delayed bone maturation and increased predicted adult height in boys with ISS. Long-term follow-up data of boys with constitutional delay of puberty, treated with letrozole for one year during adolescence, suggest that the achieved gain in predicted adult height also results in increased adult height. However, until the safety of aromatase inhibitor treatment in children and adolescents is confirmed, such treatment should be considered experimental.

Lizard Wears Shades. A Spectacled Sphenomorphus (Squamata: Scincidae), from the Sacred Forests of Mawphlang, Meghalaya, North-east India

A new species of lygosomatine scincid lizard is described from the sacred forests of Mawphlang, in Meghalaya, northeastern India. Sphenomorphus apalpebratus sp. nov. possesses a spectacle or brille, an unusual feature within the Scincidae, and a first for the paraphyletic genus Sphenomorphus. The new species is compared with other members of the genus to which it is here assigned, as well as to members of the lygosomatine genera Lipinia and Scincella from mainland India, the Andaman and Nicobar Islands, and south-east Asia, to which it also bears resemblance. The new taxon is diagnosable in exhibiting the following combination of characters: small body size (SVL to 42.0 mm); moveable eyelids absent; auricular opening scaleless, situated in a shallow depression; dorsal scales show a line of demarcation along posterior edge of ventral pes; midbody scale rows 27-28; longitudinal scale rows between parietals and base of tail 62-64; lamellae under toe IV 8-9; supraoculars five; supralabials 5-6; infralabials 4-5; subcaudals 92; and dorsum golden brown, except at dorsal margin of lateral line, which is lighter, with four faintly spotted lines, two along each side of vertebral row of scales, that extend to tail base. The new species differs from its congeners in the lack of moveable eyelids, a character shared with several distantly related scincid genera.

Informe de Economía e Instituciones

Resumen: El Informe de Economía e Instituciones cuenta con tres columnas que abordan cuestiones teóricas y de política económica relacionadas con la temática de la economía y las instituciones. En la primera columna, Analizando la crisis del Banco Central, el autor realiza un análisis en dos dimensiones: económico e institucional, de esta cuestión. En primer lugar destaca la importancia del objetivo de estabilidad monetaria entendido de forma integral, lo que implica evitar tanto la inflación como la delación por sus negativas consecuencias económicas y sociales (pobreza y desempleo). Resalta, luego, la independencia institucional del Banco Central como característica fundamental para lograr el objetivo antedicho. En la segunda columna, ¿La política económica argentina: un problema de “reglas versus discrecionalidad”?, el autor hace referencia a la importancia del debate sobre la profesionalización de la política para una democracia sana. Destaca la relevancia de la alternancia como clave de una política económica orientada al Bien Común. Por otro lado destaca la representatividad en un contexto de igualdad de oportunidades como la solución a una alternancia cíclica del sistema político. En la tercera columna, Lecciones del modelo chileno de pensiones, el autor presenta los diferentes incentivos de un sistema privado de jubilaciones y pensiones usando como ejemplo el caso de Chile. Con respecto a la Argentina, parte de la indisciplina fiscal como problema subyacente de nuestro sistema previsional. En este sentido, argumenta su escepticismo con respecto al actual sistema público e indica que el desequilibrio fiscal fue la causa principal del colapso de la reforma de 1994.

Informe de Economía e Instituciones

Resumen: El Informe de Economía e Instituciones cuenta con tres columnas que abordan cuestiones teóricas y de política económica relacionadas con la temática de la economía y las instituciones. En la primera columna, La educación como herramienta fortalecedora de la seguridad jurídica, la autora luego vincula esto con la importancia de una educación basada en valores afines a la Seguridad Jurídica. Parte de que el éxito de la creación de valor económico depende de la adecuada relación del Derecho y la Economía. Por lo que un marco jurídico claro es fundamental a la hora de cualquier tipo de gestión Económica. La autora, finalmente, concluye que el desafío de la educación hoy en día es la generación de un sistema de valores que permita que en un futuro una base de sustento solida para la necesaria Seguridad Jurídica. En la segunda columna, Instituciones y organizaciones en la gestión del desarrollo económico, el autor hace una reflexión sobre el rol de las instituciones y organizaciones, tanto públicas como privadas, en el desarrollo económico basándose en el enfoque de Douglass North. Sostiene para cumplir con las metas permanentes de una organización es necesario limitar los intereses tanto personales como grupales. Luego, hace referencia al modo de limitación de estos intereses destacando: el equilibrio de poderes y el imperio de la ley; que apuntan a limitar el personalismo y la influencia de los intereses particulares y pasiones ajenas a los objetivos de largo plazo de las organizaciones. En la tercera columna, Instituciones para la conservación de la naturaleza: Una reflexion sobre Caritas in Veritate, el autor relaciona algunos de los conceptos centrales de la Carta Encíclica Caritas in Veritate del Sumo Pontífice Benedicto XVI con la cuestión de las instituciones necesarias para la preservación del medio ambiente. Sostiene que el buen funcionamiento del sistema de mercado se sustenta en la existencia de instituciones respaldadas por el Estado. Dentro del análisis económico del ambiente expone que, en teoría, las preferencias sociales resultantes son inmanentes a las dispersas utilidades de los individuos; pero, en la práctica, los sistemas políticos adoptan mecanismos de toma de decisiones que tienden a disminuir las incoherencias que dado el contexto de la globalización actual es necesario mecanismos institucionales del mismo nivel para evitar el abuso de los recursos naturales y el medio ambiente.

Informe de Economía e Instituciones

Resumen: El Informe de Economía e Instituciones cuenta con tres columnas que abordan cuestiones teóricas y de política económica relacionadas con la temática de la economía y las instituciones. En la primera columna, Instituciones y oportunidades, la autora describe las fallas de Argentina, como de muchos países Latinoamericanos, para lograr avances significativos en la economía, tanto en la política distributiva como en la satisfacción de fines múltiples. Resalta que el problema del país no es la escasez de recursos sino la gestión de éstos, y que en muchos casos el énfasis por la distribución ha puesto en jaque la creación de riqueza. Luego plantea que la debilidad institucional impulsa un permanente cambio en las reglas de juego, y que es necesario que tanto la creación como la distribución de riqueza se complementen. En segundo lugar, menciona al “indicador de oportunidades humanas” del Banco Mundial como herramienta para medir la disponibilidad de bienes y servicios indispensables para poder progresar en la vida, “penalizado” por cuan inequitativamente están distribuidos entre la población. Concluye afirmando que está en nosotros utilizar inteligente y eficientemente los recursos brindados por el Banco Mundial y el BID para programas orientados al desarrollo y al fortalecimiento institucional. En la segunda columna, Innovaciones, Instituciones y Desarrollo Económico, el autor comienza resaltando la idea de que los procesos de innovación, claves del crecimiento económico “endógeno” en la década de 1980, eran algo que ocurría a través del tiempo e influenciados por las interacciones existentes entre los variados factores presentes en los contextos de cada caso. Procura sintetizar como, partiendo de una posición básicamente antagónica entre las innovaciones y las instituciones, se fue pasando a una versión “sistémica” en la cual lo importante era examinar con precisión cuales eran los factores que pudieran incidir (positiva o negativamente) en el avance y la concreción de las innovaciones tecnológicas deseadas. Finalmente menciona que, a través del National Innovation Systems, se procuro establecer cuales eran los factores, en cada nación, que especialmente pudieran congregarse a fin de alcanzar nacionalmente el logro de las innovaciones necesarias para apoyar el desarrollo económico deseado. En la tercera columna, El debate en torno a los sistemas de gobierno, se comenta que una amplia literatura sostiene que el desempeño económico de los países está estrechamente vinculado con sus instituciones políticas, dado que éstas configuran el contexto donde se desenvuelven los agentes. En este sentido, se menciona que no habría para un país, a priori, elección más relevante en materia institucional que la que concierne a su sistema de gobierno. Sin embargo plantea que, a pesar de que la alternativa presidencialismo versus parlamentarismo sugiere la existencia de un determinado sistema político “perfecto”, éste no existe. Concluyendo que la idoneidad del diseño depende de otros factores, como la cultura política y la tradición institucional del sistema de partidos: el contexto hace la diferencia.

Informe de Economía e Instituciones

Resumen: El Informe de Economía e Instituciones cuenta con tres columnas que abordan cuestiones teóricas y de política económica relacionadas con la temática de la economía y las instituciones. En la primera columna, Acuerdos del G-20 para enfrentar la crisis, el autor parte del diagnóstico de que la crisis financiera se profundizó, transformándose en una crisis económico–social. Luego se focaliza en el tratamiento de los asuntos globales de la cumbre de los líderes del G-20 en Londres, con el fin de establecer los lineamientos para salir de la actual crisis y sentar las bases de un nuevo orden económico mundial. Se comentan, con énfasis en lo institucional, las tareas y cambios a realizar agrupadas en torno a cinco objetivos. Estos objetivos son: restaurar el crédito, fortalecer la supervisión y la regulación financieras, fortalecer las instituciones financieras mundiales, resistir el proteccionismo y promover el comercio y la inversión mundiales y garantizar una recuperación justa y sostenible para todos. En la segunda columna, El Fideicomiso, se define que este instrumento legal se crea cuando una persona trasmite la propiedad fiduciaria de bienes determinados a otra quién se obliga a ejercerla en beneficio de quien se designe en el contrato y a trasmitirlo al cumplimiento de un plazo o condición, al beneficiario. La virtud de este instrumento es que se trata de una figura legal que aísla un patrimonio por lo que el fondo es inmune a cualquier riesgo y el fiduciario que lo administra, tiene instrucciones concretas, lo que representa una garantía fuerte. El fideicomiso en su esencia importa un negocio de confianza (fidei) en la persona del fiduciario para que éste de cumplimiento al encargo convenido en el contrato. Este es apto por sus ventajas para; fortalecer garantías y acuerdos, neutralizar riesgos, evitar procesos judiciales de ejecución con sus consecuencias de mora y costos, etc. En la tercera columna, Modernización del Estado y Articulación de Intereses, hace hincapié en la necesidad de un Estado Moderno, que es aquel que atiende eficazmente las necesidades de los ciudadanos generando asimismo adhesión al mismo. El elemento fundamental para el desarrollo de un estado moderno consiste en la independencia de los grupos de interés particular. Existen dos formas de relación entre el estado y lo grupos de interés de acuerdo a la tradición en la que uno se ubique: institucionalizadas en forma de corporaciones o instrumentalizadas mediante las actividades de los denominados lobbies. La articulación de intereses en las instituciones no es suficiente para un balance político sino que se requiere la formación de un compromiso ético y una actitud de cooperación subyacente. En cuanto a la capacidad de los grupos de intereses de balancear la acción de las agencias gubernamentales y de ejercer una acción frente a algunos desarrollos económicos, su función es invalorable siempre que sean una expresión democrática.

Estudio de la factibilidad de aplicación, a escala planta piloto, del catalizador Cr2O3/Al2O3 en la reducción de emisión de SO2 a la atmósfera, proveniente de fuentes fijas : avances 2013

Resumen: Se planificaron las experiencias con el objeto de analizar el comportamiento del catalizador en la columna metálica de mayor diámetro. Se modificaron las masas usadas para verificar la eficiencia de retención respecto de la masa. Se realizaron ciclos de adsorción, desorción y readsorción sobre una misma muestra para determinar variaciones en la eficiencia del catalizador. En otra fase, en colaboración con el Dr. V. A. Ranea y el Dr. E. E. Mola (INIFTA, UNLP), se desarrolló el estudio teórico de la adsorción de moléculas de SO2, CH4, CO2, O2 y CO sobre Cr2O3(0001) mediante Teoría del Funcional Densidad (programa VASP, Vienna Ab-initio Simulation Package), y el estudio de la cinética de la reacción entre CH4, SO2 y el O2 junto con la presencia de especies sulfito y sulfato. Este estudio permitió hallar los sitios preferenciales de adsorción de S0 y la posible competencia con SO2 experimentalmente y por cálculos teóricos. Experimentalmente, se observa que la eficiencia de adsorción del catalizador respecto al SO2 es cercana al 100%. Se observa un pico de termodesorción a 1120 K. Luego, se estudió la oxidación de CH4 con SO2. Se observa que hay producción de CO2 desde temperatura inicial, seguida de un aumento significativo en la formación de CO2 hasta 330-340 K. Luego, la producción de CO2 se mantiene aproximadamente constante. Mediante el empleo de la ecuación de Arrhenius y resultados experimentales, se obtuvo la energía de activación de la reacción global, de 7 Kcal/mol. Mediante estudios teóricos, se determinó que la energía de quimisorción del SO2 sobre el Cr2O3 es de -3.09 eV para la configuración más estable, una energía de adsorción de O2 en estado disociativo de -1.567 eV, una energía para CH4 sobre O2 adsorbido previamente de -0.335 eV, y -0.812 eV para la configuración más estable de CO2 sobre el sustrato.

Informe de Economía e Instituciones

Resumen: El Informe de Economía e Instituciones cuenta con tres columnas que abordan cuestiones teóricas y de política económica relacionadas con la temática de la economía y las instituciones. En la primera columna, Consensos sobre estrategia productiva y la lógica institucional, el autor hace un análisis de la evolución de las instituciones, tanto formales como informales, que generaron los consensos para la estrategia productiva de la Argentina. En el texto se analizan los diferentes esquemas a lo largo de la historia Argentina y las diferentes estrategias de desarrollo asociado a los mismos. Por otra parte hace hincapié en que la cooperación de los distintos actores de la sociedad civil, en este caso, los distintos sectores productivos, es clave para la consolidación de una estrategia productora sustentable. En la segunda columna, Cambio tecnológico y restricciones institucionales en Argentina, el autor hace referencia a la importancia de la calidad empresaria para el desarrollo de una Nación. Expone a lo largo del texto la relevancia económica de instituciones que permitan y fomenten la existencia de empresarios schumpeterianos en busca de cuasi rentas en contraposición a los empresarios colusivos característicos de la historia Argentina. La columna concluye así con una reflexión acerca de la importancia de la calidad empresarial de cara al desarrollo agroindustrial de la Argentina actual. En la tercer columna, Necesidad de Intensificar la Lucha contra la Corrupción, el autor expone las consecuencias sociales e institucionales de la corrupción, a partir de las palabras del Papa Benedicto XVI con motivo de la conmemoración de los 25 años del Tratado de Paz firmado por los dos países con la mediación de Juan Pablo II. Por su parte, hace especial énfasis en la importancia de instituciones sanas y las implicancias económicas en términos de eficiencia del gasto público e incentivos a la inversión. La columna ofrece un análisis de las consecuencias prácticas de la corrupción generalizada presente en la Argentina.

Informe de Economía e Instituciones

Resumen: El Informe de Economía e Instituciones cuenta con tres columnas que abordan cuestiones teóricas y de política económica relacionadas con la temática de la economía y las instituciones. En la primera columna, Los sistemas nacionales de innovación, el autor realiza una reflexión sobre la transmisión de experiencias e investigaciones técnicas realizadas para el desarrollo, acumulación y creación de conocimientos. Fundamenta el éxito innovativo en la existencia previa de interacciones creadoras de conocimiento y destaca la complejidad que para concretar valiosas innovaciones encuentran las empresas al actuar de forma aislada. Finalmente, se concluye al respecto, que los avances en materia de innovaciones tecnológicas se apoyan fundamentalmente en las interrelaciones virtuosas que pudieran existir en las investigaciones de empresas, universidades y organismos gubernamentales trabajando de manera conjunta. En la segunda columna, La calidad institucional: una asignatura pendiente, el autor expone los objetivos de fundamentales de una estructura institucional de carácter dialógico: reemplazar/encauzar el conflicto y reducir la incertidumbre. Ambos objetivos, destaca el autor, no constituyen un estado permanente sino que entrañan una cierta proyectividad. Estos requisitos se ven vulnerados cuando se cae en una institucionalidad estática o cuando esta se basa en una voluntad unilateral. En ese contexto analiza una serie de instituciones y leyes recientes, a partir de la reforma constitucional de 1994, argumentando que su desarrollo, cargado de modificaciones incesantes, permite seguir considerando la calidad institucional como una “asignatura pendiente”. En la tercera columna, Una conjetura germinal: la revolución informática explica parte de la crisis financiera internacional, el autor sostiene que la fluidez en la circulación de la información, propiciada por el desarrollo de las nuevas tecnologías de la comunicación, es una de las causas de la última crisis internacional. Para ello, traza un paralelo entre el sistema financiero internacional y un circuito eléctrico. En este sentido, argumenta que con menores costos de transacción (dada la mejora tecnológica en comunicaciones), los intercambios se tornaron más fluidos, obteniendo resultados más eficientes. De la misma manera, sucede con un circuito eléctrico donde las resistencias producen pérdidas y empeoran la eficiencia energética, pero la contraparte es que el mismo se vuelve necesariamente más inestable. Inestabilidad que se puede constatar, en términos económicos, por la existencia de burbujas especulativas. En este contexto muestra la relevancia y los efectos que el entorno institucional tiene sobre el desempeño económico.