Instituto Politécnico Nacional

About: Instituto Politécnico Nacional is a education organization based out in Mexico City, Mexico. It is known for research contribution in the topics: Population & Context (language use). The organization has 43351 authors who have published 63315 publications receiving 938532 citations. The organization is also known as: Instituto Politécnico Nacional & Instituto Politecnico Nacional.

SEPALLATA3: the 'glue' for MADS box transcription factor complex formation

Abstract: Plant MADS box proteins play important roles in a plethora of developmental processes. In order to regulate specific sets of target genes, MADS box proteins dimerize and are thought to assemble into multimeric complexes. In this study a large-scale yeast three-hybrid screen is utilized to provide insight into the higher-order complex formation capacity of the Arabidopsis MADS box family. SEPALLATA3 (SEP3) has been shown to mediate complex formation and, therefore, special attention is paid to this factor in this study. In total, 106 multimeric complexes were identified; in more than half of these at least one SEP protein was present. Besides the known complexes involved in determining floral organ identity, various complexes consisting of combinations of proteins known to play a role in floral organ identity specification, and flowering time determination were discovered. The capacity to form this latter type of complex suggests that homeotic factors play essential roles in down-regulation of the MADS box genes involved in floral timing in the flower via negative auto-regulatory loops. Furthermore, various novel complexes were identified that may be important for the direct regulation of the floral transition process. A subsequent detailed analysis of the APETALA3, PISTILLATA, and SEP3 proteins in living plant cells suggests the formation of a multimeric complex in vivo. Overall, these results provide strong indications that higher-order complex formation is a general and essential molecular mechanism for plant MADS box protein functioning and attribute a pivotal role to the SEP3 'glue' protein in mediating multimerization.

A Rule-Based Approach to Aspect Extraction from Product Reviews

Abstract: Sentiment analysis is a rapidly growing research field that has attracted both academia and industry because of the challenging research problems it poses and the potential benefits it can provide in many real life applications. Aspect-based opinion mining, in particular, is one of the fundamental challenges within this research field. In this work, we aim to solve the problem of aspect extraction from product reviews by proposing a novel rule-based approach that exploits common-sense knowledge and sentence dependency trees to detect both explicit and implicit aspects. Two popular review datasets were used for evaluating the system against state-of-the-art aspect extraction techniques, obtaining higher detection accuracy for both datasets.

Development of a selective chemical etch to improve the conversion efficiency of Zn-rich Cu2ZnSnS4 solar cells.

Abstract: Improvement of the efficiency of Cu2ZnSnS4 (CZTS)-based solar cells requires the development of specific procedures to remove or avoid the formation of detrimental secondary phases. The presence of these phases is favored by the Zn-rich and Cu-poor conditions that are required to obtain device-grade layers. We have developed a selective chemical etching process based on the use of hydrochloric acid solutions to remove Zn-rich secondary phases from the CZTS film surface, which are partly responsible for the deterioration of the series resistance of the cells and, as a consequence, the conversion efficiency. Using this approach, we have obtained CZTS-based devices with 5.2% efficiency, which is nearly twice that of the devices we have prepared without this etching process.

Participation of hepatic glucoreceptors in the control of intake of food.

Abstract: IN a previous communication1, it was shown that anorexia produced by adrenaline is easily conditioned, while anorexia produced by the injection of glucose, instead of becoming conditioned, disappears with repetition. It was also observed during this work that intraperitoneal injection of glucose had a stronger and more persistent anorectic effect than intravenous.