On The Removal of Agricultural Price Bands in Chile: A General Equilibrium Analysis

Chile has supported its agriculture with the use of price bands on selected commodities namely wheat, vegetable oils and fats, and sugar. In this paper we consider agricultural reform and how urban unemployment, and rural-urban migration, may alter the expected welfare effects of agricultural reform. We utilize a new CGE model of the Chilean economy based on the Harris-Todaro ramework, incorporating imperfect labor mobility, and consider both price band removal and more extensive agricultural reform that eliminates all tariffs on agricultural and food commodities in Chile. Results show that if trade reforms damage the rural economy in Chile, potential gains in welfare from lower agricultural prices are offset by increased urban unemployment and lower rural wages resulting in net welfare loss from trade reform.

Hidróxido de cálcio: estudo baseado em evidências científicas

The characteristics of calcium hydroxide come from its dissociation into calcium and hydroxyl ions. The action of these ions on tissues and bacteria explains the biological and antimicrobial properties of this substance. Under the conditions of this retrospective of literature, based on scientific evidences, it is possible to state that: 1. Dentin is considered the best pulpal protective, and calcium hydroxide has proved, through numerous studies, its capability of inducing the formation of a mineralized bridge over pulpal tissue. 2. It is necessary, whenever possible, to provide time for calcium hydroxide paste to manifest its potential of action on the microorganisms present in endodontic infections. The maintenance of a high concentration of hydroxyl ions can change bacteria enzymatic activity and promote its inactivation. 3. The site of action of hydroxyl ions of calcium hydroxide includes the enzymes in the cytoplasmic membrane. This medication has a large scope of action, and therefore is effective on a wide range of microorganisms, regardless their metabolic capability. In microbial world, cytoplasmic membranes are similar, irrespective from microorganisms morphological, tinctorial and respiratory characteristics, which means that this medication has a similar effect on aerobic, anaerobic, Gram-positive and Gram-negative bacteria. 4. Calcium hydroxide as temporary dressing used between appointments promotes better results on the periapical healing process than the treatment in one appointment.As características do hidróxido de cálcio se desenvolvem a partir da dissociação em íons cálcio e hidroxila. A ação desses íons nos tecidos e bactérias explica as características biológicas e antimicrobianas dessa substância. Por meio desta retrospectiva da literatura, baseada em evidências científicas, é possível afirmar que: 1. A dentina é considerada a melhor proteção pulpar, e o hidróxido de cálcio provou, através de numerosos estudos, sua capacidade de induzir a formação de barreira mineralizada sobre o tecido pulpar. 2. É necessário, sempre que possível, dar tempo à pasta de hidróxido de cálcio para manifestar seu potencial de ação sobre os microrganismos presentes nas infecções endodônticas. A manutenção de alta concentração de íons hidroxila pode alterar a atividade enzimática bacteriana e promover sua inativação. 3. O sítio de ação dos íons hidroxila e cálcio incluem as enzimas presentes na membrana citoplasmática. Esta medicação tem um largo espectro de ação, independentemente da capacidade metabólica dos microrganismos. As membranas citoplasmáticas são similares, independentemente das características morfológicas, tintoriais e respiratórias dos microrganismos, o que significa que essa medicação atua de forma similar sobre bactérias aeróbias, anaeróbias, Gram-positivas e Gram-negativas. 4. O hidróxido de cálcio como medicação intracanal, entre sessões, promove melhores resultados no processo de reparação periapical do que o tratamento em sessão única

Association of calcium hydroxide and metronidazole in the treatment of dog's teeth with chronic periapical lesion

One of the primary objectives of endodontic treatment of teeth with pulp necrosis is the elimination of microorganisms from the root canal system, as effectively as possible, especially in cases with chronic periapical lesions. AIM: The purpose of this study was to analyze the response of the periapical tissue of dogs' teeth with chronic periapical lesions to endodontic treatment performed with utilization of metronidazole, calcium hydroxide, and an association of both as root canal dressings. METHODOLOGY: Forty root canals were submitted to pulpectomy and the root canals were kept exposed to the oral environment for 6 months. Then, they were submitted to biomechanical preparation and divided into 4 study groups with 10 specimens: group I - no root canal dressing; group II - calcium hydroxide; group III - metronidazole; group IV - calcium hydroxide associated to metronidazole. After 15 days, the root canals were filled with Fill Canal sealer. After 90 days, the animals were killed and the especimens processed for histological analysis. RESULTS: Calcium hydroxide dressing provided a significantly better outcome compared to other experimental groups (alpha = 0.01). Also, the results of the association of metronidazole and calcium hydroxide were similar to those observed for the metronidazole group. The worst results were obtained by the no root canal dressing group. CONCLUSION: The use of metronidazole alone or associated with Calcium hydroxide, did not improve periapical healing when compared to Calcium hydroxide dressing.Um dos principais objetivos do tratamento endodôntico de dentes com polpa necrosada é a eliminação máxima possível dos microrganismos presentes no sistema de canal radicular, principalmente nos casos que apresentam lesões periapicais crônicas. OBJETIVO: O presente trabalho teve como objetivo analisar a resposta dos tecidos periapicais de dentes de cães com lesão periapical crônica ao tratamento endodôntico utilizando como curativo de demora o metronidazol, o hidróxido de cálcio e a associação das duas substâncias. METODOLOGIA: Foram empregados 44 canais radiculares de 2 cães adultos, portadores de lesão periapical crônica induzida experimentalmente. Após o preparo biomecânico os dentes foram divididos em quatro grupos experimentais de acordo com o curativo de demora empregado: Grupo I - controle - sem curativo de demora; Grupo II - hidróxido de cálcio; Grupo III - associação de hidróxido de cálcio e metronidazol e Grupo IV - metronidazol. Após 15 dias todos os canais foram obturados com cimento Fill Canal e passados 90 dias os animais foram sacrificados. RESULTADOS: Os dados obtidos evidenciaram que o hidróxido de cálcio apresentou resultado superior aos demais tratamentos, com diferença estatísticamente significante (alfa = 0.01) e o metronidazol resultado semelhante à associação do hidróxido de cálcio com o metronidazol. Os piores resultados foram obtidos pelo grupo sem curativo de demora. CONCLUSÃO: O uso de metronidazol ou da sua associação com hidróxido de cálcio, não proporcionou melhoras no reparo quando comparado ao curativo de hidróxido de cálcio

Factors affecting the periapical healing process of endodontically treated teeth

Tissue repair is an essential process that reestablishes tissue integrity and regular function. Nevertheless, different therapeutic factors and clinical conditions may interfere in this process of periapical healing. This review aims to discuss the important therapeutic factors associated with the clinical protocol used during root canal treatment and to highlight the systemic conditions associated with the periapical healing process of endodontically treated teeth. The antibacterial strategies indicated in the conventional treatment of an inflamed and infected pulp and the modulation of the host's immune response may assist in tissue repair, if wound healing has been hindered by infection. Systemic conditions, such as diabetes mellitus and hypertension, can also inhibit wound healing. The success of root canal treatment is affected by the correct choice of clinical protocol. These factors are dependent on the sanitization process (instrumentation, irrigant solution, irrigating strategies, and intracanal dressing), the apical limit of the root canal preparation and obturation, and the quality of the sealer. The challenges affecting the healing process of endodontically treated teeth include control of the inflammation of pulp or infectious processes and simultaneous neutralization of unpredictable provocations to the periapical tissue. Along with these factors, one must understand the local and general clinical conditions (systemic health of the patient) that affect the outcome of root canal treatment prediction

Análise histológica dos tecidos periapicais de dentes decíduos de cães após obturação de canais com diferentes materiais

The problem of finding an ideal material for filling root canals of deciduous teeth has not been solved yet. This fact led to the development of an experiment to histologically analyze the periapical tissue reaction to 3 root canal filling materials. Eighty root canals of dog deciduous anterior teeth from 6 animals, 60 days old, were used in this study. After biomechanical preparation, the root canals were filled with the following materials: slowly resorbable Maisto paste, Sealer 26 with iodoform, L&C paste (calcium hydroxide with olive oil) and as a control group, canals that were prepared but not filled. At thirty days after the treatment the animals were killed and the teeth prepared for histological analysis. The materials were ranked statistically from the best to the worst as follows: a - Maisto paste, b - Sealer 26 with iodoform, c - control group, d - L&C paste. There was significant difference (p = 0.01) only when the results of the other groups were compared with the L&C paste group. It was also observed that L&C paste was not biologically compatible and that the other materials were biocompatible but their resorption was not at the same rate as that of the deciduous teeth roots.O objetivo de encontrar um material ideal para obturar canais radiculares de dentes decíduos ainda não foi alcançado. Esse fato estimulou a realização de uma experimentação para analisar histologicamente a reação dos tecidos periapicais a 3 materiais obturadores de canal. Assim, oitenta canais radiculares de dentes decíduos anteriores de 6 cães, com 60 dias de idade, fora empregados neste estudo. Após o preparo biomecânico, os canais radiculares foram obturados com os seguintes materiais: pasta lentamente reabsorvível de Maisto, Sealer 26 com iodofórmio, pasta L&C (hidróxido de cálcio com óleo de oliva) e, como grupo controle, dentes cujos canais foram preparados biomecanicamente mas não obturados. Trinta dias após o tratamento os animais foram mortos e as peças processados para análise histológica. Os resultados permitiram ordenar estatisticamente os materiais do melhor para o pior da seguinte maneira: a- Pasta de Maisto, b- Sealer 26 com iodofórmio, c- grupo controle, d- Pasta L&C. Foi observado diferença significante (p=0,01) somente quando os resultados dos diferentes grupos foram comparados com o grupo da pasta L&C. Foi também observado que a pasta L&C não foi biologicamente compatível enquanto os outros materiais foram biocompatíveis, porém suas velocidades de reabsorção não foram a mesma observada com as raízes dos dentes decíduos

Influência do cimento obturador e de um "plug" na infiltração coronária após preparo para pino

O objetivo deste trabalho foi avaliar "in vitro" a infiltração marginal coronária após obturação de canal e preparo para pino, empregando-se ou não um "plug" protetor. Cem dentes humanos unirradiculares extraídos tiveram suas coroas removidas, e os canais preparados biomecanicamente e obturados pela técnica da condensação lateral com cones de guta-percha e os cimentos CRCS e Endofill. Após preparo para pino, os remanescentes das obturações foram ou não protegidos por 1 mm de um "plug" dos seguintes materiais: Coltosol, Super Bonder, CRCS e Endofill. Após permanecerem 24 horas em soro fisiológico, os espécimes foram imersos em solução de azul de metileno a 2%, em ambiente com vácuo, por 24 horas. Os dentes foram então seccionados longitudinalmente, as infiltrações marginais mensuradas linearmente, e os dados obtidos submetidos à análise de variância e teste de Kruskal-Wallis. Os resultados com os 2 cimentos estudados foram semelhantes entre si e piores (ñThe subject of this paper was to conduct an in vitro study of the coronal leakage after root canal filling and post space preparation. One hundred single-rooted human teeth had their crowns removed and the canals prepared and filled by the lateral condensation technique with gutta-percha points and the sealers CRCS and Endofill (a Grossman cement). After post space preparation, the remainder of the filling was protected or not with 1mm of a plug of the following materials: Coltosol, Super Bonder (cyanoacrylate-ester), CRCS and Endofill. After 24 hours in saline, the specimens were immersed in a 2% methylene blue solution in a vacuum environment for 24 hours. The teeth were then sectioned longitudinally, leakage was evaluated linearly and the obtained data were submitted to the Kruskal-Wallis test. The results with the two sealers studied were similar between themselves and worse (

Ultrastructural examination of lung “cryobiopsies” from a series of fatal COVID-19 cases hardly revealed infected cells

Ultrastructural analysis of autopsy samples from COVID-19 patients usually suffers from significant structural impairment possibly caused by the rather long latency between death of the patient and an appropriate sample fixation. To improve structural preservation of the tissue, we obtained samples from ventilated patients using a trans-bronchial “cryobiopsy” within 30 min after their death and fixed them immediately for electron microscopy. Samples of six COVID-19 patients with a documented histopathology were systematically investigated by thin section electron microscopy. The different samples and areas inspected revealed the ultrastructural correlates of the different phases of diffuse alveolar damage, including detachment of the alveolar epithelium, hyperplasia of type 2 cells, exudates, and accumulation of extracellular material, such as the hyaline membranes and fibrin. Macrophages and neutrophilic granulocytes were regularly detected. Structural integrity of endothelium was intact in regions where the alveolar epithelium was already detached. Aggregates of erythrocytes, leukocytes with fibrin, and thrombocytes were not observed. Coronavirus particles were only found in and around very few cells in one of the six patient samples. The type and origin of these cells could not be assessed although the overall structural preservation of the samples allowed the identification of pulmonary cell types. Hence, the observed alveolar damage is not associated with virus presence or structural impairment due to ongoing replication at later stages of the disease in fatal cases, which implies that the lung damage in these patients is at least propagated by alternative mechanisms, perhaps, an inappropriate immune or stress response.Peer Reviewe

The interplay of microscopic and mesoscopic structure in complex networks

Not all nodes in a network are created equal. Differences and similarities exist at both individual node and group levels. Disentangling single node from group properties is crucial for network modeling and structural inference. Based on unbiased generative probabilistic exponential random graph models and employing distributive message passing techniques, we present an efficient algorithm that allows one to separate the contributions of individual nodes and groups of nodes to the network structure. This leads to improved detection accuracy of latent class structure in real world data sets compared to models that focus on group structure alone. Furthermore, the inclusion of hitherto neglected group specific effects in models used to assess the statistical significance of small subgraph (motif) distributions in networks may be sufficient to explain most of the observed statistics. We show the predictive power of such generative models in forecasting putative gene-disease associations in the Online Mendelian Inheritance in Man (OMIM) database. The approach is suitable for both directed and undirected uni-partite as well as for bipartite networks