974 resultados para internal transcribed spacer 2
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The specific identification of Lymnaeid snails is based on a comparison of morphological characters of the shell, radula, renal and reproductive organs. However, the identification is complicated by dissection process, intra and interspecific similarity and variability of morphological characters. In the present study, polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) techniques targeted to the first and second internal transcribed spacers (ITS1 and ITS2) rDNA and to the mitochondrial 16S ribosomal gene (16S rDNAmt) were used to differentiate the species Lymnaea columella, L. viatrix, and L. diaphana from some localities of Brazil, Argentina, and Uruguay as well as to verify whether the molecular results corroborates the classical morphological method.PCR-RFLP analysis of the ITS1, ITS2, and 16S using 12 restriction enzymes revealed characteristic patterns for L. columella and L. diaphana which were concordant with the classical morphology. On the other hand, for L. viatrix populations a number of 1 to 6 profiles were generated while morphology provided the species pattern results.
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Triatoma venosa presents a restricted geographical distribution in America and is considered as a secondary vector of Chagas disease in Colombia and Ecuador. A total of 120 adult insects were collected in domestic and peridomestic habitats in an endemic area of the department of Boyacá, Colombia, in order to determine their genetic structure through morphometric and molecular techniques. The head and wings of each specimen were used for the analyses of size, shape, and sexual dimorphism. A significant sexual dimorphism was found, although no differences in size among the studied groups were detected. Differences were found in the analyzed structures except for male heads. DNA was extracted from the legs in order to carry out the internal transcriber space-2 (ITS-2) amplification and the randon amplified polymorphic DNA (RAPD) analyses. Length polymorphisms were not detected in the ITS-2. Fst and Nm values were estimated (0.047 and 3.4, respectively). The high genetic flow found among the insects captured in the domicile and peridomiciliary environment does not permit a genetic differentiation, thus establishing the peridomicile as an important place for epidemiological surveillance.
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The addition of a capped mini-exon [spliced leader (SL)] through trans-splicing is essential for the maturation of RNA polymerase (pol) II-transcribed polycistronic pre-mRNAs in all members of the Trypanosomatidae family. This process is an inter-molecular splicing reaction that follows the same basic rules of cis-splicing reactions. In this study, we demonstrated that mini-exons were added to precursor ribosomal RNA (pre-rRNA) are transcribed by RNA pol I, including the 5' external transcribed spacer (ETS) region. Additionally, we detected the SL-5'ETS molecule using three distinct methods and located the acceptor site between two known 5'ETS rRNA processing sites (A' and A1) in four different trypanosomatids. Moreover, we detected a polyadenylated 5'ETS upstream of the trans-splicing acceptor site, which also occurs in pre-mRNA trans-splicing. After treatment with an indirect trans-splicing inhibitor (sinefungin), we observed SL-5'ETS decay. However, treatment with 5-fluorouracil (a precursor of RNA synthesis that inhibits the degradation of pre-rRNA) led to the accumulation of SL-5'ETS, suggesting that the molecule may play a role in rRNA degradation. The detection of trans-splicing in these molecules may indicate broad RNA-joining properties, regardless of the polymerase used for transcription.
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Objective: To asses the results of Autologous Chondrocyte Implantation (ACI) whith periosteal patch and To propagate the care circuits existing about in Andalusia. Material and Methods: From its of ficial licence in 2005, the tissue bank and the Virgen de la Victoria Hospital from Málaga, performed the ACI in the Andalusian public health system. 16 patients has been operated between 2006-2013, whith medium follow-up 47,6 months (6 months-6 years), from public hos- pitals throughout Andalucia, managed by hospital admission source and destination. Physiologically younger patients were selected (<50 años), with singles, > 2cm2 symptomatics chondral lesions, in stables and well aligned knees. ACI was used as res- cue procedure after microfracture ́s failure except osteochondritis dissecans. To assess the results the Concinnati score and the Short Form 36 (SF-36) score were used. A descriptive analysis was performed and non-parametric tests were used to establish correlations and compare results. Results: In 15 patients with more than one year of follow-up: 14 men(87.5%) and 2women (14.5%), medium age 28.2 years old (min 17 max 43), the lesion was located into de femoral condyle, mostly in the internal one (81,2%) with medium size 2,7cm2(2-4,2). We founded significant improvement (p<0,001), both daily activities ( 89,3% preop. limitatión - 9% postop), as in the sports (90,2% preop limitatión - 38% postop) and the exploration of the knee (67,7% hpatological findings preop- 13,3%postop). The SF-36 score improved in all categories, over all in mental health (p> 0,01). The patient satisfaction was high or very high in 12 of the 15 patients ( 80%), and low in 3 patients. Conclusions: ACI improve quality of life and knee function in femoral condyle chondral lesions. The case ́s selection and the collaboration with Tissue Bank, allows us to create care circuits for treatment of patients from other provinces in the Public Sanitary Health System in Andalucia. It is necessary to increase the experience with this type of therapy, consolidating multicenter workgroups that provide strength to the conclusions.
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1 Summary This dissertation deals with two major aspects of corporate governance that grew in importance during the last years: the internal audit function and financial accounting education. In three essays, I contribute to research on these topics which are embedded in the broader corporate governance literature. The first two essays consist of experimental investigations of internal auditors' judgments. They deal with two research issues for which accounting research lacks evidence: The effectiveness of internal controls and the potentially conflicting role of the internal audit function between management and the audit committee. The findings of the first two essays contribute to the literature on internal auditors' judgment and the role of the internal audit function as a major cornerstone of corporate governance. The third essay theoretically examines a broader issue but also relates to the overall research question of this dissertation: What contributes to effective corporate governance? This last essay takes the perspective that the root for quality corporate governance is appropriate financial accounting education. r develop a public interest approach to accounting education that contributes to the literature on adequate accounting education with respect to corporate governance and accounting harmonization. The increasing importance of both the internal audit function and accounting education for corporate governance can be explained by the same recent fundamental changes that still affect accounting research and practice. First, the Sarbanes-Oxley Act of 2002 (SOX, 2002) and the 8th EU Directive (EU, 2006) have led to a bigger role for the internal audit function in corporate governance. Their implications regarding the implementation of audit committees and their oversight over internal controls are extensive. As a consequence, the internal audit function has become increasingly important for corporate governance and serves a new master (i.e. the audit committee) within the company in addition to management. Second, the SOX (2002) and the 8th EU Directive introduced additional internal control mechanisms that are expected to contribute to the reliability of financial information. As a consequence, the internal audit function is expected to contribute to a greater extent to the reliability of financial statements. Therefore, effective internal control mechanisms that strengthen objective judgments and independence become important. This is especially true when external- auditors rely on the work of internal auditors in the context of the International Standard on Auditing (ISA) 610 and the equivalent US Statement on Auditing Standards (SAS) 65 (see IFAC, 2009 and AICPA, 1990). Third, the harmonization of international reporting standards is increasingly promoted by means of a principles-based approach. It is the leading approach since a study of the SEC (2003) that was required by the SOX (2002) in section 108(d) was in favor of this approach. As a result, the Financial Accounting Standards Board (FASB) and the International Accounting Standards Board (IASB) commit themselves to the development of compatible accounting standards based on a principles-based approach. Moreover, since the Norwalk Agreement of 2002, the two standard setters have developed exposure drafts for a common conceptual framework that will be the basis for accounting harmonization. The new .framework will be in favor of fair value measurement and accounting for real-world economic phenomena. These changes in terms of standard setting lead to a trend towards more professional judgment in the accounting process. They affect internal and external auditors, accountants, and managers in general. As a consequence, a new competency set for preparers and users of financial statements is required. The basil for this new competency set is adequate accounting education (Schipper, 2003). These three issues which affect corporate governance are the initial point of this dissertation and constitute its motivation. Two broad questions motivated a scientific examination in three essays: 1) What are major aspects to be examined regarding the new role of the internal audit function? 2) How should major changes in standard setting affect financial accounting education? The first question became apparent due to two published literature reviews by Gramling et al. (2004) and Cohen, Krishnamoorthy & Wright (2004). These studies raise various questions for future research that are still relevant and which motivate the first two essays of my dissertation. In the first essay, I focus on the role of the internal audit function as one cornerstone of corporate governance and its potentially conflicting role of serving both management and the audit committee (IIA, 2003). In an experimental study, I provide evidence on the challenges for internal auditors in their role as servant for two masters -the audit committee and management -and how this influences internal auditors' judgment (Gramling et al. 2004; Cohen, Krishnamoorthy & Wright, 2004). I ask if there is an expectation gap between what internal auditors should provide for corporate governance in theory compared to what internal auditors are able to provide in practice. In particular, I focus on the effect of serving two masters on the internal auditor's independence. I argue that independence is hardly achievable if the internal audit function serves two masters with conflicting priorities. The second essay provides evidence on the effectiveness of accountability as an internal control mechanism. In general, internal control mechanisms based on accountability were enforced by the SOX (2002) and the 8th EU Directive. Subsequently, many companies introduced sub-certification processes that should contribute to an objective judgment process. Thus, these mechanisms are important to strengthen the reliability of financial statements. Based on a need for evidence on the effectiveness of internal control mechanisms (Brennan & Solomon, 2008; Gramling et al. 2004; Cohen, Krishnamoorthy & Wright, 2004; Solomon & Trotman, 2003), I designed an experiment to examine the joint effect of accountability and obedience pressure in an internal audit setting. I argue that obedience pressure potentially can lead to a negative influence on accountants' objectivity (e.g. DeZoort & Lord, 1997) whereas accountability can mitigate this negative effect. My second main research question - How should major changes in standard setting affect financial accounting education? - is investigated in the third essay. It is motivated by the observation during my PhD that many conferences deal with the topic of accounting education but very little is published about what needs to be done. Moreover, the Endings in the first two essays of this thesis and their literature review suggest that financial accounting education can contribute significantly to quality corporate governance as argued elsewhere (Schipper, 2003; Boyce, 2004; Ghoshal, 2005). In the third essay of this thesis, I therefore focus on approaches to financial accounting education that account for the changes in standard setting and also contribute to corporate governance and accounting harmonization. I argue that the competency set that is required in practice changes due to major changes in standard setting. As the major contribution of the third article, I develop a public interest approach for financial accounting education. The major findings of this dissertation can be summarized as follows. The first essay provides evidence to an important research question raised by Gramling et al. (2004, p. 240): "If the audit committee and management have different visions for the corporate governance role of the IAF, which vision will dominate?" According to the results of the first essay, internal auditors do follow the priorities of either management or the audit committee based on the guidance provided by the Chief Audit executive. The study's results question whether the independence of the internal audit function is actually achievable. My findings contribute to research on internal auditors' judgment and the internal audit function's independence in the broader frame of corporate governance. The results are also important for practice because independence is a major justification for a positive contribution of the internal audit function to corporate governance. The major findings of the second essay indicate that the duty to sign work results - a means of holding people accountable -mitigates the negative effect of obedience pressure on reliability. Hence, I found evidence that control .mechanisms relying on certifications may enhance the reliability of financial information. These findings contribute to the literature on the effectiveness of internal control mechanisms. They are also important in the light of sub-certification processes that resulted from the Sarbanes-Oxley Act and the 8th EU Directive. The third essay contributes to the literature by developing a measurement framework that accounts for the consequences of major trends in standard setting. Moreovér, it shows how these trends affect the required .competency set of people dealing with accounting issues. Based on this work, my main contribution is the development of a public interest approach for the design of adequate financial accounting curricula. 2 Serving two masters: Experimental evidence on the independence of internal auditors Abstract Twenty nine internal auditors participated in a study that examines the independence of internal auditors in their potentially competing roles of serving two masters: the audit committee and management. Our main hypothesis suggests that internal auditors' independence is not achievable in an institutional setting in which internal auditors are accountable to two different parties with potentially differing priorities. We test our hypothesis in an experiment in which the treatment consisted of two different instructions of the Chief audit executive; one stressing the priority of management (cost reduction) and one stressing the priority of the audit committee (effectiveness). Internal auditors had to evaluate internal controls and their inherent costs of different processes which varied in their degree of task complexity. Our main results indicate that internal auditors' evaluation of the processes is significantly different when task complexity is high. Our findings suggest that internal auditors do follow the priorities of either management or the audit committee depending on the instructions of a superior internal auditor. The study's results question whether the independence of the internal audit function is actually achievable. With our findings, we contribute to research on internal auditors' judgment and the internal audit function's independence in the frame of corporate governance.
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The fungus Stemphylium solani causes leaf blight of tomato (Lycopersicon esculentum) in Brazil. In recent years, severe epidemics of a new leaf blight of cotton (Gossipium hyrsutum) caused by S. solani occurred in three major cotton-growing Brazilian states (PR, MT and GO). Molecular analysis was performed to assess the genetic diversity among the S. solani isolates from cotton, and to verify their relationship with representative S. solani isolates from tomato. Random amplified polymorphic DNA (RAPD) markers and internal transcribed spacers of ribosomal DNA (rDNA) were used to compare 33 monosporic isolates of S. solani (28 from cotton and five from tomato). An isolate of Alternaria macrospora from cotton was also used for comparison. RAPD analysis showed the presence of polymorphism between the genera and the species. The A. macrospora and the S. solani isolates from cotton and tomato were distinct from each other, and fell into separate groups. Variation by geographic region was observed for the tomato isolates but not for the cotton isolates. Amplifications of the ITS region using the primer pair ITS4/ITS5 resulted in a single PCR product of approximately 600 bp for all the isolates. Similarly, when amplified fragments were digested with eight restriction enzymes, identical banding patterns were observed for all the isolates. Hence, rDNA analysis revealed no inter-generic or intra-specific variation. The genetic difference observed between the cotton and the tomato isolates provides evidence that S. solani attacking cotton in Brazil belongs to a distinct genotype.
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We apply the Bogoliubov Averaging Method to the study of the vibrations of an elastic foundation, forced by a Non-ideal energy source. The considered model consists of a portal plane frame with quadratic nonlinearities, with internal resonance 1:2, supporting a direct current motor with limited power. The non-ideal excitation is in primary resonance in the order of one-half with the second mode frequency. The results of the averaging method, plotted in time evolution curve and phase diagrams are compared to those obtained by numerically integrating of the original differential equations. The presence of the saturation phenomenon is verified by analytical procedures.
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Este artículo revisa hallazgos y modelos teóricos en torno a un aspecto del desarrollo de la teoría de la mente, a saber: la comprensión temprana de cómo se adquiere el conocimiento. La revisión realizada indica que mientras la investigación inicial sugiere que esta comprensión emerge a los cuatro años de edad, hallazgos recientes indican que se encuentra ya presente al final del primer año de vida. A partir de esto, la teoría emergente sobre el aprendizaje cultural propuesta por Tomasello y colaboradores propone la integración de ambos hallazgos en una misma trayectoria de desarrollo. A pesar de sus contribuciones, esta novedosa propuesta podría enriquecerse de dos distintas formas: 1) esclareciendo las diferencias específicas en cuanto a la capacidad del infante y la del niño preescolar para comprender los estados mentales como representaciones internas, y 2) especificando los mecanismos que subyacen la trayectoria de desarrollo de la comprensión del comportamiento como el producto de la actividad mental.
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Land plants have had the reputation of being problematic for DNA barcoding for two general reasons: (i) the standard DNA regions used in algae, animals and fungi have exceedingly low levels of variability and (ii) the typically used land plant plastid phylogenetic markers (e.g. rbcL, trnL-F, etc.) appear to have too little variation. However, no one has assessed how well current phylogenetic resources might work in the context of identification (versus phylogeny reconstruction). In this paper, we make such an assessment, particularly with two of the markers commonly sequenced in land plant phylogenetic studies, plastid rbcL and internal transcribed spacers of the large subunits of nuclear ribosomal DNA (ITS), and find that both of these DNA regions perform well even though the data currently available in GenBank/EBI were not produced to be used as barcodes and BLAST searches are not an ideal tool for this purpose. These results bode well for the use of even more variable regions of plastid DNA (such as, for example, psbA-trnH) as barcodes, once they have been widely sequenced. In the short term, efforts to bring land plant barcoding up to the standards being used now in other organisms should make swift progress. There are two categories of DNA barcode users, scientists in fields other than taxonomy and taxonomists. For the former, the use of mitochondrial and plastid DNA, the two most easily assessed genomes, is at least in the short term a useful tool that permits them to get on with their studies, which depend on knowing roughly which species or species groups they are dealing with, but these same DNA regions have important drawbacks for use in taxonomic studies (i.e. studies designed to elucidate species limits). For these purposes, DNA markers from uniparentally (usually maternally) inherited genomes can only provide half of the story required to improve taxonomic standards being used in DNA barcoding. In the long term, we will need to develop more sophisticated barcoding tools, which would be multiple, low-copy nuclear markers with sufficient genetic variability and PCR-reliability; these would permit the detection of hybrids and permit researchers to identify the 'genetic gaps' that are useful in assessing species limits.
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Tribe Pogonieae (Orchidaceae), as Currently known, comprises live genera distributed from South to North America and Eastern Asia. Phylogenetic inferences within Cleistes and among genera of tribe Pogonieae were made based oil nrDNA (ITS) and cpDNA (trnL-F, rps16, rbcL, and psaB) Sequence data and maximum parsimony. Eighteen species of Cleistes, members of all other genera of Pogonieae, and outgroups were sampled. Analyses based oil individual DNA regions provided similar topologies. All evidence indicates that Cleistes is paraphyletic. The North American C. divaricata and C bifaria are more closely related to the temperate genera Isotria and Pogonia than to their Central and South American congeners, the latter Constituting a monophyletic group characterized by the production of nectar as reward, tuberous roots, and their distribution in Central and South America. The Amazonian Duckeella is sister to the remainder of Pogonieae. Taxonomic and biogeographic implications are discussed, and morphological synapomorphies are given For clades obtained in the inferred molecular phylogeny. (C) 2008 Gesellschaft fur Biologische Systematik. Published by Elsevier GmbH. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fungi isolated in Brazil, from lettuce, broccoli, spinach, melon and tomato, were identified as Rhizoctonia solani. All lettuce isolates anastomosed with both AG 1-IA and IB subgroups and all isolates from broccoli, spinach, melon and tomato anastomosed with AG 4 subgroup HG-I, as well as with subgroups HG-II and HG-III. DNA sequence analyses of ribosomal internal transcribed spacers showed that isolates from lettuce were AG 1-IB, isolates from tomato and melon were AG 4 HG-I, and isolates from broccoli and spinach were AG 4 HG-III. The tomato isolates caused stem rot symptoms, the spinach, broccoli and melon isolates caused hypocotyl and root rot symptoms on the respective host plants and the lettuce isolates caused bottom rot. This is the first report on the occurrence in Brazil of R. solani AG 4 HG-I in tomato and melon, of AG 4 HG-III in broccoli and spinach and of AG 1-IB in lettuce.
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In this paper we describe Southern blot hybridization results probed with 5S rRNA genes for several Neotropical fish species representing different taxonomic groups. All the studied species showed a general trend with the 5S rDNA tandem repeats organized in two distinct size-classes. At the same time, data on 5S rDNA organization in fish genome were summarized. Previous information on the organization and evolution of 5S rRNA gene arrays in the genome of this vertebrate group are in agreement with the Southern results here presented. Sequences obtained for several fish species have revealed the occurrence of two distinct 5S rDNA classes characterized by distinct non-transcribed spacer sequences, which are clustered in different chromosomes in some species. Moreover, the 5S rDNA loci are generally distributed in an interstitial position in the chromosomes and they are usually not syntenic to the 45S rDNA. The presence of two classes of 5S rDNA in several non-related fish species suggests that this could be a common condition for the 5S rRNA gene organization in the fish genome.
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In higher eukaryotes, the 5S ribosomal DNA (5S rDNA) is organized in tandem arrays with repeat units composed of a coding region and a non-transcribed spacer sequence (NTS). These tandem arrays can be found on either one or more chromosome pairs. 5S rDNA copies from the tilapia fish. Oreochromis niloticus, were cloned and the nucleotide sequences of the coding region and of the non-transcribed spacer were deter-mined. Moreover, the genomic organization of the 5S rDNA tandem repeats was investigated by fluorescence in situ hybridization (FISH) and Southern blot hybridization. Two 5S rDNA classes, one consisting of 1.4-kb repeats and another one with 0.5-kb repeats were identified and designated 5S rDNA type I and type II, respectively, An inverted 5S rRNA gene and a 5S rRNA putative pseudogene were also identified inside the tandem repeats of 5S rDNA type I. FISH permitted the visualization of the 5S rRNA genes at three chromosome loci, one of them consisting of arrays of the 5S rDNA type I, and the two others corresponding to arrays of the 5S rDNA type II. The two classes of the 5S rDNA. The presence of pseudogenes, and the inverted genes observed in the O. niloticus genome might be a consequence of the intense dynamics of the evolution of these tandem repeat elements. Copyright (C) 2002 S. Karger AG, Basel.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)