Kirkolla oli vahva rooli keskiaikaisissa kauhutarinoissa

Kirjallisuusarvostelu

Vuosi pyhimysten kanssa

Kirjallisuusarvostelu

Efeito de herbicidas na atividade microbiana do solo

Objetivou-se com este trabalho avaliar os efeitos de herbicidas e doses na atividade microbiana e no potencial de solubilização de fosfato inorgânico de solo cultivado com cana-de-açúcar. Os tratamentos foram constituídos pelos herbicidas ametryn, trifloxysulfuron-sodium e pela mistura (ametryn + trifloxysulfuron-sodium), aplicados nas doses de 0, 1, 2, 4 e 8 vezes a dose-referência de 10, 0,112 e 7,315 + 0,185 mg dm-3 do ingrediente ativo dos respectivos herbicidas. Após aplicação dos tratamentos, as amostras de solo foram incubadas por 15 dias, realizando-se as avaliações da evolução de CO2 do solo (C-CO2) em intervalos de três dias. Ao final do período de incubação foram realizadas análises de carbono da biomassa microbiana (CBM), quociente metabólico (qCO2), potencial de solubilização e solubilização relativa de fosfato inorgânico do solo. A evolução de C-CO2 foi influenciada pelas maiores doses dos herbicidas, sendo reduzida com a aplicação do trifloxysulfuron-sodium (10,31%) e elevada com os demais herbicidas, com maiores efeitos logo após a aplicação. O CBM e o qCO2 foram influenciados negativamente pelos herbicidas ametryn e trifloxysulfuron-sodium + ametryn, com maiores efeitos quanto maiores as doses. O trifloxysulfuron-sodium provocou a redução do CBM nas menores doses e incremento deste nas maiores, promovendo a redução do qCO2. A solubilização potencial de fosfato inorgânico decresceu com a aplicação do ametryn (47,20%) e da mistura (13,55%), sendo estimulada pelo trifloxysulfuron-sodium (25,48%). O potencial de solubilização relativa teve comportamento semelhante.

Sotaa, naisia ja ylellisyyttä Aurinkokuninkaan tapaan

Kirjallisuusarvostelu

Produção de compostos fenólicos durante a infecção ectomicorrízica por dois isolados de Pisolithus tinctorius em Eucalyptus urophylla in vitro

Devido à grande variedade fisiológica e morfológica entre os fungos ectomicorrízicos, é possível observar variações no seu comportamento durante o estabelecimento da simbiose. Este trabalho teve como objetivos caracterizar as etapas da infecção micorrízica por dois isolados de P. tinctorius em E. urophylla, além de verificar a ocorrência de defesas estruturais e bioquímicas na planta. Plântulas de E. urophylla foram inoculadas com os isolados de P. tinctorius obtidos de eucalipto (1604) ou de Pinus (185). Após 0, 12, 24, 72, 96 e 120 horas da inoculação com cada um dos isolados, foi efetuada a dosagem de compostos fenólicos no tecido radicular. Nestes mesmos períodos foram feitos cortes anatômicos das raízes para verificar o desenvolvimento da infecção. Os cortes histológicos não evidenciaram reações estruturais de defesa das plantas nestes períodos testados. No entanto, foi observada colonização mais rápida pelo isolado 1604, o qual iniciou a adesão à raiz 24 horas após a inoculação. O isolado 185 só foi observado na raiz após 96 horas. A dosagem de compostos fenólicos mostrou variação significativa durante a infecção pelo isolado 185 e maior concentração nas raízes inoculadas com este isolado após 96 horas da inoculação. Porém, este acúmulo não impediu a continuidade de seu desenvolvimento na raiz. Neste trabalho não foi observada relação entre o atraso na infecção pelo isolado 185 e a produção de compostos fenólicos pelas raízes.

Kaikki maailman teurastajat

Kirjallisuusarvostelu

Kajavien kohtaloita ihmisiän mitalla

Kirjallisuusarvostelu

Populaari kertomus nälänhädästä ja suurista kuolonvuosista

Kirjallisuusarvostelu

Lognormal abundance distribution of woody species in a cerrado fragment (São Carlos, southeastern Brazil)

The lognormal distribution model is frequently found in communities, especially those which are rich in species and influenced by many environmental factors, as those of the cerrado. We tested the hypothesis that the abundance distribution of woody plant species in a cerrado fragment fits the lognormal model. We placed 20 lines in a cerrado fragment and sampled, with the point-quarter method, 800 individuals with stem perimeter equal or larger than 3 cm. We plotted the abundance-class histogram of the species, verified its normality with the Kolmogorov-Smirnov test, and estimated the expected number of woody species for this community. Of the 63 obtained species, Anadenanthera falcata (with 185 species), Eriotheca gracilipes (43), Stryphnodendron obovatum (37), and Miconia albicans (36) were the most abundant ones. Twelve species were represented by only one individual. We did not reject the null hypotheses that the distribution of woody component species was normal and, thus, their abundances fitted the lognormal model. Therefore, with our work, we can predict that cerrado plant communities fit the lognormal model. If this pattern is maintained in other cerrado communities, there would be implications for the conservation of this vegetation type, because rare species are susceptible of extinction, and implications to their structure, because the dominant species may act as keystone species.

Preparation of mitotic chromosomes of leaf-cutting ants from the genera Atta and Acromyrmex

Some modifications were made to the methodology of Imai et al. (Jpn. J. Genet. 63: 159-185, 1988) for cytogenetic analysis of the leaf-cutting ants Atta sexdens piriventris and Acromyrmex heyeri (Hymenoptera, Formicidae), shortening preparation time and improving chromosomal preparations. The brain ganglia of prepupae were dissected in a 0.0025% hypotonic solution of colchicine, placed on a glass slide on a cold plate (4 ± 1oC) for 20 min. The material was fixed directly on the cold slide (with cold fixative I), macerated with a histological needle and fixed again with fixative I, followed by fixatives II and III, all of them cold. The slide was flame-dried right after the use of fixative III, and it was allowed to air-dry at room temperature for 2 h. The resulting metaphases presented less contracted chromosomes, with separated and well defined sister chromatids at a high frequency, when the material was processed in the manner described and stained with 3% Giemsa in phosphate buffer (pH 6.8) for 15 min.

Baroreflex and chemoreflex dysfunction in streptozotocin-diabetic rats

Several investigators have demonstrated that streptozotocin (STZ) diabetes induces changes in the autonomic control of the cardiovascular system. Changes in cardiovascular function may be related to peripheral neuropathy. The aim of the present study was to analyze changes in heart rate (HR) and arterial pressure (AP) as well as baroreflex and chemoreflex sensitivity in STZ-induced diabetic male Wistar rats (STZ, 50 mg/kg, iv, 15 days). Intra-arterial blood pressure signals were obtained for control and diabetic rats (N = 9, each group). Data were processed in a data acquisition system (CODAS, 1 kHz). Baroreflex sensitivity was evaluated by measuring heart rate changes induced by arterial pressure variation produced by phenylephrine and sodium nitroprusside injection. Increasing doses of potassium cyanide (KCN) were used to evaluate bradycardic and pressor responses evoked by chemoreflex activation. STZ induced hyperglycemia (447 ± 49 vs 126 ± 3 mg/dl), and a reduction in AP (99 ± 3 vs 118 ± 2 mmHg), resting HR (296 ± 11 vs 355 ± 16 bpm) and plasma insulin levels (16 ± 1 vs 57 ± 11 µU/ml). We also observed that the reflex bradycardia (-1.68 ± 0.1 vs -1.25 ± 0.1 bpm/mmHg, in the diabetic group) and tachycardia (-3.68 ± 0.5 vs -1.75 ± 0.3 bpm/mmHg, in the diabetic group) produced by vasopressor and depressor agents were impaired in the diabetic group. Bradycardia evoked by chemoreflex activation was attenuated in diabetic rats (control: -17 ± 1, -86 ± 19, -185 ± 18, -208 ± 17 vs diabetic: -7 ± 1, -23 ± 5, -95 ± 13, -140 ± 13 bpm), as also was the pressor response (control: 6 ± 1, 30 ± 7, 54 ± 4, 59 ± 5 vs diabetic: 6 ± 1, 8 ± 2, 33 ± 4, 42 ± 5 mmHg). In conclusion, the cardiovascular responses evoked by baroreflex and chemoreflex activation are impaired in diabetic rats. The alterations of cardiovascular responses may be secondary to the autonomic dysfunction of cardiovascular control

Algorithmic Techniques in Gene Expression Processing. From Imputation to Visualization

The amount of biological data has grown exponentially in recent decades. Modern biotechnologies, such as microarrays and next-generation sequencing, are capable to produce massive amounts of biomedical data in a single experiment. As the amount of the data is rapidly growing there is an urgent need for reliable computational methods for analyzing and visualizing it. This thesis addresses this need by studying how to efficiently and reliably analyze and visualize high-dimensional data, especially that obtained from gene expression microarray experiments. First, we will study the ways to improve the quality of microarray data by replacing (imputing) the missing data entries with the estimated values for these entries. Missing value imputation is a method which is commonly used to make the original incomplete data complete, thus making it easier to be analyzed with statistical and computational methods. Our novel approach was to use curated external biological information as a guide for the missing value imputation. Secondly, we studied the effect of missing value imputation on the downstream data analysis methods like clustering. We compared multiple recent imputation algorithms against 8 publicly available microarray data sets. It was observed that the missing value imputation indeed is a rational way to improve the quality of biological data. The research revealed differences between the clustering results obtained with different imputation methods. On most data sets, the simple and fast k-NN imputation was good enough, but there were also needs for more advanced imputation methods, such as Bayesian Principal Component Algorithm (BPCA). Finally, we studied the visualization of biological network data. Biological interaction networks are examples of the outcome of multiple biological experiments such as using the gene microarray techniques. Such networks are typically very large and highly connected, thus there is a need for fast algorithms for producing visually pleasant layouts. A computationally efficient way to produce layouts of large biological interaction networks was developed. The algorithm uses multilevel optimization within the regular force directed graph layout algorithm.