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Los bosques de Pinus hartwegii son susceptibles al ataque de plagas forestales, por ello las intervenciones de saneamiento en los rodales de esta especie deben ser analizadas. El objetivo de este trabajo fue evaluar los efectos de las cortas de saneamiento sobre el crecimiento radial del arbolado residual, en rodales de P. hartwegii del Área de Protección de Flora y Fauna Nevado de Toluca. Se establecieron diez sitios de medición de árboles remanentes y tocones en rodales intervenidos durante 2016 (1000 m2) en las exposiciones Oeste y Este del volcán. Se consideró el período de los años 2013-2015 como previo al saneamiento, y 2016-2018 como posterior al saneamiento. Se analizaron el patrón de distribución y la estructura horizontal y vertical. Se calcularon dos índices de densidad y dos índices de competencia. Se colectaron núcleos de madera en todos los individuos y se midieron las anchuras de los anillos de crecimiento mediante técnicas dendrocronológicas. Se estandarizó el crecimiento mediante series de incremento en área basal (IAB). El crecimiento de los árboles remanentes ubicados en la periferia de los tocones fue significativamente diferente entre las exposiciones. El IAB aumentó 37.3% después del saneamiento en la exposición Oeste, mientras que en la exposición Este el IAB aumentó 61.6%. Los árboles remanentes ubicados entre los 2.5 m y 5 m con respecto al tocón tuvieron mayores IAB en ambas exposiciones. Los bosques de Pinus hartwegii responden de manera favorable a las cortas de saneamiento con un aumento estadísticamente significativo en el IAB.

Cut stumps are the legacy of forest harvesting and allow for the estimation of carbon loss from the ecosystem. The objective of this study was to estimate aboveground carbon storage and the impact of forest harvesting based on measurements of cut stumps in pine forests within the Area de Proteccion de Flora y Fauna Nevado de Toluca (APFFNT) in the state of Mexico. A total of 1621 circular 0.1-ha sampling plots were established in a 12,924 ha pine forest (1.25% sampling intensity). Biomass was calculated using conventional volumetric equations incorporating species-specific wood densities. Aboveground carbon storage in the biomass was stratified by forest type including dense forest (≥ 336 trees), semi-dense forest ( 150 trees), fragmented forest ( 20 trees), and stands with isolated trees (

Background Spontaneous bleedings occurring into joints (hemarthrosis) are the most common manifestations of hemophilia and causes severe joint damage ultimately resulting in joint disfunction known as hemophilic arthropathy. Among available therapeutic options for reducing recurrent hemarthrosis-associated damage, radiosynoviorthesis (RS) has proven effective in improving joint function. Aim To assess the impact of RS with Yttrium(90) citrate (C-Y(90)) on frequency of hemarthroses and joint function in a group of pediatric patients. Methods Between November 1998 and February 2017, we evaluated 27 pediatric patients with mild, moderate or severe hemophilia with haemophilic arthropathy. Overall, RS was applied in 60 joints. Some patients received more than one single intra-articular injection with C-Y(90). Results During the follow-up, one patient showed joint bleeding 15 months after RS, one patient after 12 months and one patient after 45 days. The episodes of hemarthrosis were reduced and joint function significantly improved in all patients. Conclusion RS with C-Y(90) is a simple and safe treatment for reducing the frequency of hemarthroses in patients with hemophilia. It decreases the use of factor VIII / IX and improves joint function.

Non-cell-autonomous mechanisms contribute to neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), in which astrocytes release unidentified factors that are toxic to motoneurons (MNs). We report here that mouse and patient iPSC-derived astrocytes with diverse ALS/FTD-linked mutations (SOD1, TARDBP, and C9ORF72) display elevated levels of intracellular inorganic polyphosphate (polyP), a ubiquitous, negatively charged biopolymer. PolyP levels are also increased in astrocyte-conditioned media (ACM) from ALS/FTD astrocytes. ACM-mediated MN death is prevented by degrading or neutralizing polyP in ALS/FTD astrocytes or ACM. Studies further reveal that postmortem familial and sporadic ALS spinal cord sections display enriched polyP staining signals and that ALS cerebrospinal fluid (CSF) exhibits increased polyP concentrations. Our in vitro results establish excessive astrocyte-derived polyP as a critical factor in non-cell-autonomous MN degeneration and a potential therapeutic target for ALS/FTD. The CSF data indicate that polyP might serve as a new biomarker for ALS/FTD.

La dendroecología es una subdisciplina de la dendrocronología, que se refiere al estudio de los procesos ecológicos en un bosque por medio del análisis de anillos de crecimiento de los árboles de un rodal. Esta subdisciplina es útil para comprender la dinámica de crecimiento en condiciones naturales y de manejo. El objetivo del presente estudio fue hacer una revisión sobre la aplicación de la dendroecología como herramienta en manejo forestal. Se identificaron 78 trabajos que involucraron 118 especies. Los países donde se ha realizado un mayor número de estudios dendroecológicos son Estados Unidos de América, España y Argentina. Las prácticas de manejo que fueron mayormente beneficiadas con el uso de métodos dendroecológicos son la estimación del tiempo de turno en la fase de planeación. el aclareo en la fase de ejecución. y las evaluaciones de crecimiento y rendimiento, así como los impactos de plagas y enfermedades sobre el crecimiento en la fase de monitoreo. La investigación en manejo forestal se sustenta principalmente en el seguimiento de parcelas permanentes de medición y puede ser fortalecida por el análisis de anillos de crecimiento. Los métodos dendrocronológicos proporcionan información relevante sobre la estructura del bosque, el estado fitosanitario, las tasas de crecimiento de especies arbóreas y su variación temporal. Las experiencias de la investigación dendroecológica llevada a cabo en otros países pueden aplicarse también en México, incluyendo el estudio de especies latifoliadas. El uso de la dendroecología como herramienta para el manejo forestal contribuiría a optimizar la producción maderable y favorecería la conservación de los ecosistemas forestales en el país.

Background Hexanucleotide repeat expansions of the G4C2 motif in a non-coding region of the C9ORF72 gene are the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Tissues from C9ALS/FTD patients and from mouse models of ALS show RNA foci, dipeptide-repeat proteins, and notably, widespread alterations in the transcriptome. Epigenetic processes regulate gene expression without changing DNA sequences and therefore could account for the altered transcriptome profiles in C9ALS/FTD; here, we explore whether the critical repressive marks H3K9me2 and H3K9me3 are altered in a recently developed C9ALS/FTD BAC mouse model (C9BAC). Results Chromocenters that constitute pericentric constitutive heterochromatin were visualized as DAPI- or Nucblue-dense foci in nuclei. Cultured C9BAC astrocytes exhibited a reduced staining signal for H3K9me3 (but not for H3K9me2) at chromocenters that was accompanied by a marked decline in the global nuclear level of this mark. Similar depletion of H3K9me3 at chromocenters was detected in astrocytes and neurons of the spinal cord, motor cortex, and hippocampus of C9BAC mice. The alterations of H3K9me3 in the hippocampus of C9BAC mice led us to identify previously undetected neuronal loss in CA1, CA3, and dentate gyrus, as well as hippocampal-dependent cognitive deficits. Conclusions Our data indicate that a loss of the repressive mark H3K9me3 in astrocytes and neurons in the central nervous system of C9BAC mice represents a signature during neurodegeneration and memory deficit of C9ALS/FTD.

Amyotrophic lateral sclerosis is a fatal neurodegenerative disease and studies in vitro show that motoneuron degeneration is triggered by non-cell-autonomous mechanisms. However, whether soluble toxic factor(s) released by mutant superoxide dismutase 1 (SOD1) expressing astrocytes induces death of motoneurons and leads to motor dysfunction in vivo is not known. To directly test this, healthy adult rats were treated with conditioned media derived from primary mouse astrocytes (ACM) that express human (h) SOD1G93A (ACM-hG93A) via chronic osmotic pump infusion in the lumbar spinal cord. Controls included ACM derived from transgenic mice expressing hSOD1WT (ACM-hWT) or non-transgenic mouse SOD1WT (ACM-WT) astrocytes. Rats chronically infused with ACM-hG93A started to develop motor dysfunction at 8 days, as measured by rotarod performance. Additionally, immunohistochemical analyses at day 16 revealed reactive astrogliosis and significant loss of motoneurons in the ventral horn of the infused region. Controls did not show significant motor behavior alterations or neuronal damage. Thus, we demonstrate that factors released in vitro from astrocytes derived from ALS mice cause spinal motoneuron death and consequent neuromuscular dysfunction in vivo.

Para estimar la densidad básica de la madera de Pinus hartwegii del volcán La Malinche se utilizaron dos métodos: el tradicional de máximo contenido de humedad (Smith, 1954) y el empírico propuesto recientemente (Valencia y Vargas, 1997); para ello se extrajeron 22 especímenes pequeños de madera con un taladro de Pressler a los que se les aplicaron ambos métodos. Se encontró que los valores promedio, de desviación estándar, mínimo y máximo de densidad de la madera fueron muy semejantes. Se determinó la densidad básica de la madera en 0,496 g/cm'. Se demostró con una correlación simple que los resultados de ambos métodos fue cercana a la unidad . La madera de Pínus hartwegií se clasifica como moderadamente pesada. El valor de densidad obtenido en este estudio puede utilizarse en estimaciones de biomasa referentes a la especie.

A forest plantation, product of the reforestation of pine trees, represented a pool of biological resources for the implementation of a solid state fermentation process. The trees were identified as Pinus pseudostrobus Lindl from which lignocellulosic material in the form of pine needles was collected. Soil fungi, responsible for plant litter decomposition, were cultured at laboratory conditions and tested for their ability to grow on cellulose and hemicellulose as the sole carbon sources. A fungal strain, belonging to the genus Penicillium, was selected for growing it on pine needles as the substrate in a solid state culture. After following the culture for six days, the newly isolated strain exhibited a much higher capacity for spore production and holocellulose degradation, compared to a purchased strain of Penicillium chrysogenum and two control conditions. This work marks the beginning of future studies focused on commercial applications and represents the first report of a biotechnological process based on pine needles and their degradation by an ascomycetes species belonging to the genus Penicillium.

Highlights • Sequencing results were in agreement for biologically conserved positions. • For biologically variable positions, sequencing depth impacted precision. • Results were biased by the algorithm used to align reads to the reference., This study presents the results from an interlaboratory sequencing study for which we developed a novel high-resolution method for comparing data from different sequencing platforms for a multi-copy, paralogous gene. The combination of PCR amplification and 16S ribosomal RNA gene (16S rRNA) sequencing has revolutionized bacteriology by enabling rapid identification, frequently without the need for culture. To assess variability between laboratories in sequencing 16S rRNA, six laboratories sequenced the gene encoding the 16S rRNA from Escherichia coli O157:H7 strain EDL933 and Listeria monocytogenes serovar 4b strain NCTC11994. Participants performed sequencing methods and protocols available in their laboratories: Sanger sequencing, Roche 454 pyrosequencing®, or Ion Torrent PGM®. The sequencing data were evaluated on three levels: (1) identity of biologically conserved position, (2) ratio of 16S rRNA gene copies featuring identified variants, and (3) the collection of variant combinations in a set of 16S rRNA gene copies. The same set of biologically conserved positions was identified for each sequencing method. Analytical methods using Bayesian and maximum likelihood statistics were developed to estimate variant copy ratios, which describe the ratio of nucleotides at each identified biologically variable position, as well as the likely set of variant combinations present in 16S rRNA gene copies. Our results indicate that estimated variant copy ratios at biologically variable positions were only reproducible for high throughput sequencing methods. Furthermore, the likely variant combination set was only reproducible with increased sequencing depth and longer read lengths. We also demonstrate novel methods for evaluating variable positions when comparing multi-copy gene sequence data from multiple laboratories generated using multiple sequencing technologies.

Insect species, especially those considered to be pests, can be exploited for human consumption. One of the most devastating pest insect species in central Mexico is the grasshopper Sphenarium purpurascens. Here we develop a sustainable exploitation strategy that produces a considerable biomass of S. purpurascens while minimising the damage they cause to agricultural fields by changing the chemical control methods to a mechanical method. In this model the biomass-per-stage of grasshoppers that can be extracted annually using the mechanical method was calculated and their potential abundance was estimated using Maxent. With a calculated population density of 10-55 individuals of S. purpurascens per m2 over approximately 1,050,000 ha of the agroecosystems in Mexico, the estimated biomass of this insect averaged 350,000 tons per year (generating a gross income of US$ 3.5×108 million). Unlike chemical control methods, mechanical control has no toxic effects on human populations or other species inside or outside of the agroecosystems. Promoting a change from chemical to mechanical control methods of pest species could greatly impact on the health of millions of people globally and on the environment, reducing carbon dioxide and methane emissions, land clearing and the use of pesticides while obtaining economic profit.

The methods for measuring vegetation cover in Mexican forest surveys are subjective and imprecise. The objectives of this research were to compare the sampling designs used to measure the vegetation cover and estimate the over and understory cover in different land uses, using digital photography. The study was carried out in 754 circular sampling sites in central Mexico. Four spatial sampling designs were evaluated in three spatial distribution patterns of the trees. The sampling designs with photographic captures in diagonal form had lower values of mean absolute error (MAE < 0.12) and less variation in random and grouped patterns. The Carbon and Biomass Sampling Plot (CBSP) design was chosen due to its smaller error in the different spatial tree patterns. The image processing was performed using threshold segmentation techniques and was automated through an application developed in the Python language. The two proposed methods to estimate vegetation cover through digital photographs were robust and replicable in all sampling plots with different land uses and different illumination conditions. The automation of the process avoided human estimation errors and ensured the reproducibility of the results. This method is working for regional surveys and could be used in national surveys due to its functionality.

Background Neuroinflammation involves cytokine release, astrocyte reactivity and migration. Neuronal Thy-1 promotes DITNC1 astrocyte migration by engaging αVβ3 Integrin and Syndecan-4. Primary astrocytes express low levels of these receptors and are unresponsive to Thy-1; thus, inflammation and astrocyte reactivity might be necessary for Thy-1-induced responses. Methods Wild-type rat astrocytes (TNF-activated) or from human SOD1G93A transgenic mice (a neurodegenerative disease model) were used to evaluate cell migration, Thy-1 receptor levels, signaling molecules, and reactivity markers. Results Thy-1 induced astrocyte migration only after TNF priming. Increased expression of αVβ3 Integrin, Syndecan-4, P2X7R, Pannexin-1, Connexin-43, GFAP, and iNOS were observed in TNF-treated astrocytes. Silencing of β3 Integrin prior to TNF treatment prevented Thy-1-induced migration, while β3 Integrin over-expression was sufficient to induce astrocyte reactivity and allow Thy-1-induced migration. Finally, hSOD1G93A astrocytes behave as TNF-treated astrocytes since they were reactive and responsive to Thy-1. Conclusions Therefore, inflammation induces expression of αVβ3 Integrin and other proteins, astrocyte reactivity, and Thy-1 responsiveness. Importantly, ectopic control of β3 Integrin levels modulates these responses regardless of inflammation. Electronic supplementary material The online version of this article (10.1186/s12974-017-0968-5) contains supplementary material, which is available to authorized users.

Amyotrophic lateral sclerosis is a fatal neurodegenerative disease and studies in vitro show that motoneuron degeneration is triggered by non-cell-autonomous mechanisms. However, whether soluble toxic factor(s) released by mutant superoxide dismutase 1 (SOD1) expressing astrocytes induces death of motoneurons and leads to motor dysfunction in vivo is not known. To directly test this, healthy adult rats were treated with conditioned media derived from primary mouse astrocytes (ACM) that express human (h) SOD1

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease in which pathogenesis and death of motor neurons are triggered by non-cell-autonomous mechanisms. We showed earlier that exposing primary rat spinal cord cultures to conditioned media derived from primary mouse astrocyte conditioned media (ACM) that express human SOD1(G93A) (ACM-hSOD1(G93A)) quickly enhances Nav channel-mediated excitability and calcium influx, generates intracellular reactive oxygen species (ROS), and leads to death of motoneurons within days. Here we examined the role of mitochondrial structure and physiology and of the activation of c-Abl, a tyrosine kinase that induces apoptosis. We show that ACM-hSOD1(G93A), but not ACM-hSOD1(WT), increases c-Abl activity in motoneurons, interneurons and glial cells, starting at 60 min; the c-Abl inhibitor STI571 (imatinib) prevents this ACM-hSOD1(G93A)-mediated motoneuron death. Interestingly, similar results were obtained with ACM derived from astrocytes expressing SOD1(G86R) or TDP43(A315T). We further find that co-application of ACM-SOD1(G93A) with blockers of Nav channels (spermidine, mexiletine, or riluzole) or anti-oxidants (Trolox, esculetin, or tiron) effectively prevent c-Abl activation and motoneuron death. In addition, ACM-SOD1(G93A) induces alterations in the morphology of neuronal mitochondria that are related with their membrane depolarization. Finally, we find that blocking the opening of the mitochondrial permeability transition pore with cyclosporine A, or inhibiting mitochondrial calcium uptake with Ru360, reduces ROS production and c-Abl activation. Together, our data point to a sequence of events in which a toxic factor(s) released by ALS-expressing astrocytes rapidly induces hyper-excitability, which in turn increases calcium influx and affects mitochondrial structure and physiology. ROS production, mediated at least in part through mitochondrial alterations, trigger c-Abl signaling and lead to motoneuron death.

Although the efficacy and safety of combining first-line chemotherapy with bevacizumab in elderly patients with colorectal cancer (CRC) is supported by the results of a phase III trial, real-practice data are limited.Our multi-center, community-based observational study included 233 elderly patients with CRC (median age=73 years, range=70-84 years). Baseline comorbidities and geriatric evaluation were also analyzed. Pre-specified end-points of the study were safety, tolerability and outcome results.The incidence of both chemotherapy-induced and specific bevacizumab-related toxicities was low, and not influenced by baseline concurrent morbidities. Median progression free survival (PFS) and median overall survival (OS) were 9.9 months and 23.6 months, respectively. Fifty-six percent of patients received second-line chemotherapy.The upfront treatment of older patients with CRC with chemotherapy and bevacizumab is safe and efficacious in a real-world setting. No un expected toxicities were reported. Multi-dimensional geriatric evaluation is under-used in clinical practice.

International audience; Key messageWe present a comprehensive database of 478 allometric equations to estimate biomass of trees and other life forms in Mexican forest and scrubland ecosystems.ContextAccurate estimation of standing biomass in forests is a prerequisite for any approach to carbon storage and a number of additional applications.AimsTo provide a comprehensive database with allometric equations applicable to a large number of tree and shrub species of Mexico.MethodsAn intensive literature search was carried out to pull together all publications related to allometric equations in the libraries of the most important forest research institutes across Mexico and the neighboring countries.ResultsA total of 478 equations were compiled. Four hundred fourteen equations included a detailed analysis of all compartments of the trees; 7 equations applied to shrubs, 15 to bamboos, and 2 to palms. The collected equations are applicable to a wide variety of forest ecosystems in Mexico ranging from desert scrublands in the North to lowland evergreen rainforests in the South. The attached database of allometric equations is possibly the most extensive compilation of equations currently available for Mexico.ConclusionThe database covers almost 100 % of the individuals recorded in the National Forest Inventory.

In recent years educational models have been changed in order to establish teaching-learning processes to set up profiles and professionalize the academic education actively. A didactic strategy is problem based learning (PBL). The purpose of this research is to analyze the impact of PBL on university students’ through social meaning that it represent themselves. Method: it was used a mixed methodology. The analysis unit was social meaning about PBL, which was analyzed through the natural semantic network technique. The sample was composed by 93 psychology students of the University of Colima in three different grades (3, 5 and 7). The test used was an open question questionnaire type. The results obtained in the SAM group showed that the main defining words with highest social representativeness regarding to PBL are: research, learning, team, analysis and debate. RESUMEN En anos recientes se han modificado los modelos educativos con el fin de establecer procesos de ensenanza-aprendizaje que instauren perfiles y profesionalicen la formacion universitaria de manera activa. Una estrategia didactica es el aprendizaje basado en problemas (ABP). El objetivo de la presente investigacion es analizar el impacto que tiene el ABP en los estudiantes universitarios a traves del significado social que representa para los mismos. Se empleo una metodologia mixta. La unidad de analisis fue el significado social del ABP, el cual se estudio a traves de la tecnica red semantica natural. La muestra estuvo conformada por 93 estudiantes de tres diferentes semestres (3, 5 y 7) de la Licenciatura en Psicologia, Universidad de Colima. El instrumento utilizado fue un cuestionario con preguntas abiertas. Los resultados obtenidos en el conjunto SAM, muestran que las principales palabras definidoras con mayor representatividad respecto al ABP son: investigacion, aprendizaje, equipo, analisis y debate. Contacto principal: fabiola_rola@yahoo.com.mx

Amyotrophic lateral sclerosis (ALS) is a fatal paralytic disorder caused by dysfunction and degeneration of motor neurons. Multiple disease-causing mutations, including in the genes for SOD1 and TDP-43, have been identified in ALS. Astrocytes expressing mutant SOD1 are strongly implicated in the pathogenesis of ALS: we have shown that media conditioned by astrocytes carrying mutant SOD1(G93A) contains toxic factor(s) that kill motoneurons by activating voltage-sensitive sodium (Na v ) channels. In contrast, a recent study suggests that astrocytes expressing mutated TDP43 contribute to ALS pathology, but do so via cell-autonomous processes and lack non-cell-autonomous toxicity. Here we investigate whether astrocytes that express diverse ALS-causing mutations release toxic factor(s) that induce motoneuron death, and if so, whether they do so via a common pathogenic pathway. We exposed primary cultures of wild-type spinal cord cells to conditioned medium derived from astrocytes (ACM) that express SOD1 (ACM-SOD1(G93A) and ACM-SOD1(G86R)) or TDP43 (ACM-TDP43(A315T)) mutants; we show that such exposure rapidly (within 30-60 min) increases dichlorofluorescein (DCF) fluorescence (indicative of nitroxidative stress) and leads to extensive motoneuron-specific death within a few days. Co-application of the diverse ACMs with anti-oxidants Trolox or esculetin (but not with resveratrol) strongly improves motoneuron survival. We also find that co-incubation of the cultures in the ACMs with Na v channel blockers (including mexiletine, spermidine, or riluzole) prevents both intracellular nitroxidative stress and motoneuron death. Together, our data document that two completely unrelated ALS models lead to the death of motoneuron via non-cell-autonomous processes, and show that astrocytes expressing mutations in SOD1 and TDP43 trigger such cell death through a common pathogenic pathway that involves nitroxidative stress, induced at least in part by Na v channel activity.

Amyotrophic lateral sclerosis (ALS) is a fatal motoneuron disease with no current effective treatment. Accumulation of abnormal protein inclusions containing SOD1, TARDBP, FUS, among other proteins, is a pathological hallmark of ALS. Autophagy is the major degradation pathway involved in the clearance of damaged organelles and protein aggregates. Although autophagy has been shown to efficiently degrade ALS-linked mutant protein in cell culture models, several studies suggest that autophagy impairment may also contribute to disease pathogenesis. In this report, we tested the potential use of trehalose, a disaccharide that induces MTOR-independent autophagy, in the development of experimental ALS. Administration of trehalose to mutant SOD1 transgenic mice significantly prolonged life span and attenuated the progression of disease signs. These effects were associated with decreased accumulation of SOD1 aggregates and enhanced motoneuron survival. The protective effects of trehalose were associated with increased autophagy levels in motoneurons. Cell culture experiments demonstrated that trehalose led to mutant SOD1 degradation by autophagy in NSC34 motoneuron cells and also protected primary motoneurons against the toxicity of conditioned media from mutant SOD1 transgenic astrocytes. At the mechanistic level, trehalose treatment led to a significant upregulation in the expression of key autophagy-related genes at the mRNA level including Lc3, Becn1, Sqstm1 and Atg5. Consistent with these changes, trehalose administration enhanced the nuclear translocation of FOXO1, an important transcription factor involved in the activation of autophagy in neurons. This study suggests a potential use of trehalose and enhancers of MTOR-independent autophagy for the treatment of ALS.

Amyotrophic lateral sclerosis (ALS) is a devastating paralytic disorder caused by dysfunction and degeneration of motoneurons starting in adulthood. Recent studies using cell or animal models document that astrocytes expressing disease-causing mutations of human superoxide dismutase 1 (hSOD1) contribute to the pathogenesis of ALS by releasing a neurotoxic factor(s). Neither the mechanism by which this neurotoxic factor induces motoneuron death nor its cellular site of action has been elucidated. Here we show that acute exposure of primary wild-type spinal cord cultures to conditioned medium derived from astrocytes expressing mutant SOD1 (ACM-hSOD1G93A) increases persistent sodium inward currents (PCNa), repetitive firing, and intracellular calcium transients, leading to specific motoneuron death days later. In contrast to TTX, which paradoxically increased twofold the amplitude of calcium transients and killed motoneurons, reduction of hyperexcitability by other specific (mexiletine) and nonspecific (spermidine and riluzole) blockers of voltage-sensitive sodium (Nav) channels restored basal calcium transients and prevented motoneuron death induced by ACM-hSOD1G93A. These findings suggest that riluzole, the only FDA-approved drug with known benefits for ALS patients, acts by inhibiting hyperexcitability. Together, our data document that a critical element mediating the non-cell-autonomous toxicity of ACM-hSOD1G93A on motoneurons is increased excitability, an observation with direct implications for therapy of ALS.

Objetivo: Obtener la concordancia de técnicas diagnósticas y confirmar el diagnóstico de los casos probables de tos ferina captados por inmunofluorescencia directa (IFD) durante un brote en 2013 en el departamento de Antioquia. Materiales y métodos: Se analizaron los datos demográficos, clínicos, epidemiológicos y de resultados de laboratorio de casos probables de tos ferina confirmados por IFD en un pico de tos ferina en 2013 en el departamento de Antioquia. Las muestras de aspirado nasofaríngeo y suero fueron recolectadas y recibidas entre los periodos epidemiológicos IV - VII de 2013. Todos los pacientes confirmados por IFD fueron confirmados por PCR o ELISA. El análisis de concordancia se realizó por índice kappa. Resultados: De las 180 muestras procesadas en el LSP de Antioquia, 134 (74%) fueron positivas por la técnica de IFD, de las cuales se confirmaron por PCR 109 muestras con 24 (22%) positivas para B. parapertussis , 3 (2,8%) para B. pertussis , 17 (15,6%) para Bordetella spp. y 18 (16,5%) con infección mixta por B. pertussis y B. parapertussis . De 81 casos que se confirmaron por ELISA, 31 (38,3%) fueron positivos. En el municipio de La Estrella la edad media de los casos confirmados fue de 6,6 años y la mediana de 3 años (rango: 2-4 años). Con respecto a los casos del municipio de Medellín, la edad media fue de 28,7 años y la mediana de 25 años (rango: 12-42 años). En su mayoría, en los síntomas no hubo diferencias significativas, excepto para la tos paroxística entre los casos confirmados de B. parapertussis y B. pertussis (p =

In 1851 the french mathematician Charles Hermite showed that the Galois group and monodromy coincide in the context of algebraic geometry. However, it was Joe Harris (in 1979) that presented this result and applications in a modern language. In this work initially we introduce the Galois group and monodromy in the context of algebraic geometry following the lines of the article "Galois groups of enumerative problems"[10]. Next we determine the monodromy group of the inflection points of a non-singular plane cubic. Since this group is soluble, we determine the coordinates of these points from the Weierstrass equation of such cubic. We conclude by reviewing Harris'results about the monodromy group of lines in non-singular cubic surfaces, emphasizing the calculation of these lines from the equation that defines a non-singular cubic surface containing three lines two by two prefixed disjoint (according Mckean-Minaham-Zhang, 2020 ([16])). Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES Em 1851 o matemático francês Charles Hermite mostrou que o grupo de Galois e monodromia coincidem no contexto de geometria algébrica. Entretanto, foi Joe Harris (em 1979) que apresentou esse resultado e aplicações numa linguagem moderna. Neste trabalho inicialmente introduzimos o grupo de Galois e monodromia no contexto de geometria algébrica seguindo as linhas do artigo "Galois groups of enumerative problems"([10]). A seguir determinamos o grupo de monodromia dos pontos de inflexão de uma cúbica plana não singular. Sendo esse grupo solúvel, determinamos as coordenadas desses pontos a partir da equação de Weierstrass de tal cúbica. Concluímos revisando os resultados de Harris sobre o grupo de monodromia de retas em superfícies cúbicas não singulares, dando ênfase ao cálculo dessas retas a partir da equação que define uma superfície cúbica não singular contendo três retas duas a duas disjuntas prefixadas (conforme Mckean-Minaham-Zhang, 2020 ([16])).

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR PROGRAMA DE EXCELENCIA ACADEMICA O Grupo de Cremona é o grupo das Transformações birracionais do plano projetivo e tem um papel muito importante em Geometria Birracional. Pelo Teorema de Nöether-Castelnuovo (final do século XIX), o Grupo de Cremona é gerado pelos automorfismos do plano projetivo e pela Transformação Quadrática Padrão. Apesar de compreendermos bem o grupo de automorfismos do Plano Projetivo e a Transformação Quadrática Padrão, o estudo do Grupo de Cremona é bastante desafiador, e sua estrutura ainda não é totalmente conhecida. Somente em 2013, Cantat e Lamy provaram que o Grupo de Cremona não é simples no caso de um corpo algebricamente fechado. Em 2016, Anne Lonjou provou o mesmo para qualquer corpo. Ambas as provas se baseiam em uma ação por isometrias do Grupo de Cremona em um espaço hiperbólico de dimensão infinita. Nosso objetivo será entender essa ação e como ela pode ser usada no estudo do Grupo de Cremona. The Cremona Group is the group of Birrational Transformations of the projective plane and has a very important role in Birrational Geometry. By the Nöether-Castelnuovo Theorem (late 19th century), the Cremona Group is generated by the automorphisms of the projective plane and by the Standard Quadratic Transformation. Although we understand well the group of automorphisms of the projective plane and the Standard Quadratic Transformation, the study of the Cremona Group is quite challenging, and its structure is not yet fully known. Only in 2013, Cantat and Lamy proved that the Cremona Group is not simple in the case of an algebraically closed field. In 2016, Anne Lonjou proved the same for any field. Both proofs are based on an action by isometries of the Cremona Group in a hyperbolic space of infinite dimension. Our goal will be to understand this action and how it can be used in the study of the Cremona Group.

Let r(S) be the maximum number of pairwise disjunct lines that a non-singular surface S ⊂ P3 contains and rd = max {r(S) | deegre(S) = d}. Ensure that r(S) = 6 for all non-singular cubic surface S, therefore r3 = 6. For d = 4, r4 = 16, it was showed by the Russian mathematician Viacheslav Nikulin in [9]. We quote that Rojas-Santos in [7], obtained that r(F) = 16 if F is the Schur’s quartic. At the moment rd is unknown for d ≥ 5. In this work we aim to present bounds for the maximum number of two-by-two disjunct straight lines in the family S whose members are the deegre d non-singular surfaces Sd ⊂ P3 definided by φ(x0,x1)−φ(x2,x3) being φ(u,v) = uv(ud−2−vd−2) and d ≥ 5. In fact, for d odd we show that r(Sd) = d(d−2) + 4, however Boiss´ere-Sarti proved that r(Sd) ≥ d(d−2) + 4 when d is odd and d ≥ 7 in [3]. For the even case, we obtain d(d−2) + 4 ≤ r(Sd) ≤ d(d−2) + d2 2 if d 6= 6 and r(S6) = 48. Considering the bound rd ≤ d(d−2) for all d ≥ 4 given by the Japanese mathematician Miyaoka in [8], we conclude as soon as r6 = 48. Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq Sejam r(S) a quantidade máxima de retas duas a duas disjuntas que a superfície não singular S ⊂P3 pode conter e rd =max{r(S) | grau(S) = d}. Verifica-se que r(S) = 6 para toda superfície cúbica não singular S, logo r3 = 6. Para d = 4, r4 = 16, conforme foi demonstrado pelo matemático russo Viacheslav Nikulin em [9]. Salientamos que Rojas-Santos em [7], mostraram que r(F) = 16 se F for a quártica de Schur. No momento rd é desconhecido se d ≥ 5. Neste trabalho, objetivamos apresentar cotas para o numero máximo de retas duas a duas disjuntas na família S, sendo S formada pelas superfícies não singulares Sd ⊆ P3 de grau d, definidas por φ(x0,x1)−φ(x2,x3) sendo φ(u,v) = uv(ud−2 − vd−2) e d ≥ 5. De fato, no caso d´ ímpar mostramos que r(Sd) = d(d−2)+4 sendo que Boiss´ere-Sarti mostraram que r(Sd) ≥ d(d−2)+4 se d é ímpar e d ≥ 7 em [3]. E no caso d par, mostramos que d(d−2)+4 ≤ r(Sd) ≤ d(d−2)+ d2 2 se d 6= 6 e r(S6) = 48. Tendo em consideração a cota do matemático japonês Miyaoka em [8] tem-se rd ≤ 2d(d−2) para todo d ≥ 4, concluímos assim que r6 = 48.

This work aims to determine the maximum number of pairwise disjoint lines that a non-singular surface of degree d in P3 can contain. In the case of degrees d = 1 and d = 2 we found that these values are zero and in nite, respectively. Furthermore, in the case of degree d = 3 we did show that the maximum number of pairwise disjoint lines is 6, these con gurations were studied in 1863 by the Swiss Ludwig Schl a i (1814-1895) in [15]. For the case d = 4, in 1975 the Russian Viacheslav Nikulin in [10] showed that non-singular quartic surfaces contain at most 16 pairwise disjoint lines. In our work, we have been able to show that Schur's famous quartic achieves this bound and that Fermat's quartic has at most 12 pairwise disjoint lines. We also determined lower bounds for the maximum number of pairwise disjoint lines in the case of non-singular surfaces of degree d 5. For example, the Rams's family in [11] allows us to nd one of these lower bounds. Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES Este trabalho objetiva determinar a quantidade máxima de retas duas a duas disjuntas que uma superfície não singular de grau d em P3 pode conter. No caso dos graus d = 1 e d = 2 verificamos que estes valores s~ao zero e in nito, respectivamente. Al em disso, no caso de grau d = 3 mostramos que o n umero m aximo de retas duas a duas disjuntas e 6, ditas con gura c~oes foram estudadas em 1863 pelo sui co Ludwig Schl a i (1814-1895) em [15]. Para o caso d = 4, em 1975 o russo Viacheslav Nikulin em [10] mostrou que as superf cies qu articas n~ao singulares cont^em no m aximo 16 retas duas a duas disjuntas. No nosso trabalho, conseguimos mostrar que a famosa qu artica de Schur atinge essa cota e que qu artica de Fermat possui no m aximo 12 retas duas a duas disjuntas. Determinamos ainda cotas inferiores para o n umero m aximo de retas duas a duas disjuntas no caso de superf cies n~ao singulares de grau d 5. Por exemplo, a fam lia de Rams em [11] nos permite achar uma dessas cotas inferiores.

In 1943 Beniamino Segrebelievedtohaveshownthatthemaximumnumberof lines containedinasmoothquarticsurfacein P3 is 64, ([16]).Butrecently,therewasa majoroverturnonthatthemewhenthemathematiciansRamsandSchuttfoundthat Segre hadmadeamistakeinhisworktoforgetthequartic'sfamily Z , ([14]),which essentiallycorrespondstothosequarticscontainingalinesthatcanbeincidenttomore than 18 lines containedinthesurface.Inthiswork,basedon([14]),weshowthatevery smoothquarticsurface,whichdoesnotbelongtofamily Z containsamaximumof 64 lines. Oneofthemostimportanttoolstoshowthisresult,isthestudyof_brations _l induced byaline l containedonthesurface,andtherelationshipbetweentheEuler characteristicofthebase(P1 in ourcase),the_bersandthesurfaceconcerned. Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq Em 1943,BeniaminoSegreacreditouterdemonstradoqueonúmeromáximo de retascontidasnumasuperfíciequárticanãosingularem P3 é 64; ([16]). Mas recentemente,houveumareviravoltanessetema,quandoosmatemáticosSªawomir Rams eMatthiasSchüttconstataramqueSegretinhacometidoumerroemseutrabalho ao esquecerasquárticasdafamília Z; ([14]), quecorrespondemessencialmenteas quárticas quepossuemretasquepodemserincidentesamaisde 18 retas contidas na superfície.Nestetrabalho,tendocomobase[14],mostramosquetodaquártica não singular,quenãopertenceafamília Z; contémnomáximo 64 retas. Umadas ferramentasmaisimportantes,paramostraresseresultado,éoestudodas_brações _l induzida porumareta l contidanasuperfície,earelaçãoqueexisteentrea característica deEulerdabase(emnossocaso P1), das_brassingulareseadasuperfície em questão.

It is well-known that planes and quadric surfaces in the projective space contain in - nitely many lines. For smooth cubic surface Cayley and Salmon, 1847, (and Clebsch later) proved that it has exactly 27 lines. For degree 4, in 1943 Segre proved that the maximum number of lines contained in a smooth quartic surface is 64. For surfaces of degree greater than 4 this number is unknown. In this work, we are going to explore what is the maximum number of lines that a smooth complex surface of degree d of the family Fd ; may contain. Thus, we obtain a lower bound to the maximum number of lines that non singular surfaces of degree d in P3 may contain. We emphasize that the determination of this numbers is based on the Klein's classi cation theorem of nitte subgroups of Aut(P1) and the study of C; the subgroup of Aut(P1) whose elements leaves invariant the nite subset C of P1: Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES Sabe-se que planos e superf cies qu adricas no espa co projetivo cont em in nitas retas. No caso de uma superf cie c ubica n~ao singular Cayley e Salmon, em 1847, (e Clebsch, mais tarde) provaram que ela cont em exatamente 27 retas. No caso de grau 4, em 1943 Segre provou que o n umero m aximo de retas contidas numa superf cie qu artica n~ao singular e 64. Para superf cies de grau maior que 4 esse n umero e desconhecido. Neste trabalho vamos explorar qual e a quantidade m axima de retas que uma superf cie complexa n~ao singular de grau d na fam lia Fd ; pode conter. Assim obtemos uma cota inferior para o n umero m aximo de retas que as superf cies n~ao singulares de grau d em P3 podem conter. Salientamos que a determina c~ao destes n umeros tem como base o Teorema de Classi ca cao de Klein dos sugbrupos nitos de Aut(P1) e o estudo dos subgrupos C de Aut(P1) que deixam invariante um subconjunto nito C de P1

The notions of connection and covariant derivative has its origin in the field of Riemannian geometry , where there is no distinction between them. In fact, in this study we found that these notions are equivalent if we consider modules over K-algebras of finite type. We also show that the existence of connections implies the existence of covariant derivative. The main goal of this study is to determine which modules admit connections. We easily verified that the projective modules admit connections. In fact, they form an affine space. But we also display a module that is not projective and has connection. Later, inspired by Swan's theorem, we explore in a straightforward way modules formed by sections of the tangent bundle of some surfaces in 3-dimensional real space. Finally, we study the notion of connection introduced by Alain Connes in modules over K-algebras not necessarily commutative. And we find in that context that the modules that have connection are exactly the projectives modules. Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES As noções de conexão e derivada covariante tem sua origem na área de geometria riemanniana, onde não existe distinção entre elas. De fato, nós verificamos neste trabalho, que estas noções são equivalentes se considerarmos módulos sobre K-álgebras comutativas de tipo finito. Também mostramos que a existência de conexões implica na existência de derivada covariante. O objetivo central deste trabalho é determinar que módulos admitem conexão. Verificamos facilmente que os módulos projetivos admitem conexões. De fato, elas formam um espaço afim. Mas também exibimos um módulo não projetivo que possui conexão. Posteriormente, inspirados pelo teorema de Swan, exploramos de maneira direta os módulos formados pelas seções do fibrado tangente de algumas superfícies no espaço 3- dimensional real. Por fim, estudamos a noção de conexão introduzida por Alain Connes em módulos sobre K-álgebras não necessariamente comutativas. E verificamos nesse contexto que os módulo que admitem conexão são exatamente os módulos projetivos.

In this work are introduced the concepts of involutive affine and projective varieties. Taking into account that every projective variety in P2n-1 has dimension greater than or equal to n-1 and that every hypersurface is involutive, we put our focus on the study of involutive curves in P3, noting that a curve in P3 contained in a plane will be involutive if and only if it is a union of lines passing through the point associated to the suported by plane the correspondence between points and planes determined by the standard symplectic form in P3. We started using the Poisson bracelete invariance of the definition ideal of a varity criterion to determine the involutive lines and conics in P3. Moreover, we exhibit a family of involutive twisted curves. Finally, having in mind that the parameters spaces for involutive lines and conics are 3 and 5 dimensional spaces, respectively. We find how many involutive lines and conic meet 3 and 5 given lines in P3, respectively. Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES Neste trabalho são introduzidos os conceitos de variedades involutiva afim e projetiva. Tendo em consideração que toda variedade projetiva em P2n-1 tem dimensão maior ou igual a n-1 e que toda hipersuperfície é involutiva, colocamos nosso foco no estudo das curvas involutivas em P3, destacando que uma curva em P3 contida em um plano será involutiva se, e somente, se for uma união de retas passando pelo ponto associado ao plano suporte, pela correspondência entre planos e pontos determinada pela forma simplética padrão em P3. Começamos utilizando o critério da invariância do ideal de definição da variedade sob o colchete de Poisson para determinar as retas e cônicas involutivas em P3. Em seguida, exibimos famílias de cúbicas reversas involutivas. Finalmente, tendo em consideração que os espaços de parâmetros determinados para retas e cônicas involutivas tem dimensão 3 e 5, respectivamente, discutimos o problema de determinar quantas retas (resp. cônicas) involutivas encontram simultaneamente 3 (resp. 5) retas dadas em P3.

In this dissertation we expose the solve the four line problem in Schubert Calculus using the Plucker embedding, giving emphasis to the study of the relative position of the four given lines in P3, this allows us to obtain an explicit description of the solution's set as well as to give the precise meaning to the notion of general position. In chapter 1, we insert the notion of projective space and other related, which are the basic notions for addressing the problem that we treat. In chapter 2, we introduce the Plucker embedding, !, which allows us to identify the set of lines that meet a xed given line l0 with the intersection of the Plucker's quadric, Q, and the tangent space of Q at !(l0). We also give the description of all the linear varieties contained in the Plucker's quadric Q. Finally, in chapter 3 we demonstrate the Theorem 3.0.3 which is a key ingredient to and solutions for our problem. Moreover, we establish a relationship between the relative position of the four given lines and their solution's set. Finally, we conclude in the appendix with the Shapiro-Shapiro conjecture in the case of the four line problem in Schubert Calculus. Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Neste trabalho expomos a resolução do problema das 4 retas do Cálculo de Schubert utilizando o mergulho de Plücker, com ênfase no estudo da posição relativa das 4 retas dadas em P3, o que nos permite obter uma descrição explícita do conjunto de soluções é dar sentido preciso à noção de posição geral. No capítulo 1 inserimos a noção de espaço projetivo e outras correlatas que servirão de base no estudo do problema a ser resolvido. No capítulo 2 introduzimos o Mergulho de Plücker, ω, o qual nos permite identificar o conjunto das retas que encontram uma reta fixa l0 com a interseção da quádrica de Plücker e o espaço tangente à mesma no ponto ω l0. Além disso damos a descrição das variedades lineares contidas na quádrica de Plücker. Porém, no capítulo 3 demonstramos o Teorema 3.0.3 que é a chave para resolução do nosso problema e fazemos a descrição do conjunto solução cada para posição relativa possível das 4 retas. Concluímos com um apêndice onde tratamos da conjectura de Shapiro-Shapiro no caso do problema das quatro retas do cálculo de Shubert.

Hesse said in one of his articles that a hypersurface in the projective space Pn that has null hessian polynomial is a cone. Later, Gordam and Noether prove that the statement of Hesse is valid only for n 3, presenting counter-examples for n 4. Initially we tried to solve the problem in a direct and elementary form, been well succeeding only in the case of P1, so we set out to study the dual of variety and polar map associated to the hypersurface X = Z(F) Pn. Having mind that X IF , where IF is the polar map image, and that X is a cone if and only if, X is degenerate. Which brings us to display a series of technical results in order to conclude that IF is a linear variety, speci cally a line if n = 2 and a plane or line if n = 3. Thus we prove for a given hypersurface X = Z(F) Pn. If n 3, then X is a Cone () det [Hess (F)] = 0. Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Hesse a rmou em um dos seus artigos que uma hipersuperfície no espaço projetivo Pn que tenha o hessiano polinomial nulo é um cone. Mais tarde, Gordam e Noether provam que a a rmação de Hesse é valida apenas para n 3, apresentando contra- exemplos para n 4. Inicialmente tentamos resolver o problema de maneira direta e elementar, tendo sucesso só no caso de P1, então partimos para o estudo de dual de uma variedade e de mapa polar associado a uma hipersuperfície X = Z(F) Pn. Tendo em consideração que X IF , onde IF é a imagem do mapa polar, e que X é um Cone se, e somente se, X é degenerado. Somos levados a mostrar uma série de resultados técnicos a m de concluir que IF é uma variedade linear, especi camente uma reta se n = 2 e um plano ou uma reta se n = 3. Provando assim que dada uma hipersuperfície X = Z(F) Pn. Se n 3, então X é um cone () det [Hess (F)] = 0.