Determinantes da intensidade das fusões e aquisições num contexto de incerteza

Dissertação de mestrado em FinançasTendo como referência o mercado Europeu durante os anos 2001 a 2012, este estudo tem por objetivo determinar as motivações que estão na génese das F&A em diferentes cenários económicos. A principal conclusão é que as empresas recorrem às F&A com diferentes objetivos, fazendo com que o timing ótimo seja diferente consoante as motivações. Ganho de eficiência pela obtenção de economias de escala, diversificação ou desinvestimento terão um trigger de investimento diferente. Adicionalmente, neste estudo verifica-se uma relação em forma de um U invertido com a tendência de crescimento da economia e do setor da empresa. Esta relação altera-se quando a amostra é subdividida em duas subamostras (horizontais e não horizontais). Prevalece como relevante o desempenho da economia para a determinação do momento ótimo para a ocorrência de F&A horizontais e as tendências de crescimento da economia e setor sobre as F&A não horizontais. Por último conclui-se também que integrações horizontais não são influenciadas pela incerteza. Contrariamente as integrações não horizontais, constata-se que ocorrem com mais frequência em cenários económicos mais voláteis. Verifica-se que a relação entre a probabilidade da ocorrência de um anúncio de uma F&A não horizontal e a incerteza do setor apresenta uma forma quadrática, revelando existir um ponto ótimo, onde a probabilidade é máxima, que desponta a ocorrência da fusão.Having the European market as reference during the years 2001 to 2012, the purpose of this study is to determine the motivations behind M&A in various economic scenarios. The main conclusion is that the companies apply to the M&A regarding different purposes, making the optimal timing vary according to the motivations. Efficiency gains through the use scope economies, diversification or disinvestment will cause a trigger of different investment. Furthermore, in this study an inverted “U-shape” was found evidencing the tendency of the economic growth and the company’s sector. This relation changes when the sample is divided in two subsamples (horizontal and non-horizontal). The performance of the economy prevails as a relevant factor to the determination of the optimal instant allowing the horizontal M&A to occur, thus the tendency of economic and sector growth over the non-horizontal M&A’s. Finally, it is deduced that horizontal integrations are not influenced by uncertainty. Contrarily to the non-horizontal integrations, it is stated that they occur more frequently in more volatile economic scenario. The relation between the likelihood of a non-horizontal M&A announce and the sector’s uncertainty reveals a quadratic shape, proving that there is an optimal point, where the probability is a maximum, which emerges the occurrence of a fusion

Diazotrophic Bacterial Community of Degraded Pastures

Pasture degradation can cause changes in diazotrophic bacterial communities. Thus, this study aimed to evaluate the culturable and total diazotrophic bacterial community, associated with regions of the rhizosphere and roots of Brachiaria decumbens Stapf. pastures in different stages of degradation. Samples of roots and rhizospheric soil were collected from slightly, partially, and highly degraded pastures. McCrady’s table was used to obtain the Most Probable Number (MPN) of bacteria per gram of sample, in order to determine population density and calculate the Shannon-Weaver diversity index. The diversity of total diazotrophic bacterial community was determined by the technique of Denaturing Gradient Gel Electrophoresis (DGGE) of the nifH gene, while the diversity of the culturable diazotrophic bacteria was determined by the Polymerase Chain Reaction (BOX-PCR) technique. The increase in the degradation stage of the B. decumbens Stapf. pasture did not reduce the population density of the cultivated diazotrophic bacterial community, suggesting that the degradation at any degree of severity was highly harmful to the bacteria. The structure of the total diazotrophic bacterial community associated with B. decumbens Stapf. was altered by the pasture degradation stage, suggesting a high adaptive capacity of the bacteria to altered environments

Genome of the Avirulent Human-Infective Trypanosome—Trypanosoma rangeli

Background: Trypanosoma rangeli is a hemoflagellate protozoan parasite infecting humans and other wild and domestic mammals across Central and South America. It does not cause human disease, but it can be mistaken for the etiologic agent of Chagas disease, Trypanosoma cruzi. We have sequenced the T. rangeli genome to provide new tools for elucidating the distinct and intriguing biology of this species and the key pathways related to interaction with its arthropod and mammalian hosts.  Methodology/Principal Findings: The T. rangeli haploid genome is ,24 Mb in length, and is the smallest and least repetitive trypanosomatid genome sequenced thus far. This parasite genome has shorter subtelomeric sequences compared to those of T. cruzi and T. brucei; displays intraspecific karyotype variability and lacks minichromosomes. Of the predicted 7,613 protein coding sequences, functional annotations could be determined for 2,415, while 5,043 are hypothetical proteins, some with evidence of protein expression. 7,101 genes (93%) are shared with other trypanosomatids that infect humans. An ortholog of the dcl2 gene involved in the T. brucei RNAi pathway was found in T. rangeli, but the RNAi machinery is non-functional since the other genes in this pathway are pseudogenized. T. rangeli is highly susceptible to oxidative stress, a phenotype that may be explained by a smaller number of anti-oxidant defense enzymes and heatshock proteins.  Conclusions/Significance: Phylogenetic comparison of nuclear and mitochondrial genes indicates that T. rangeli and T. cruzi are equidistant from T. brucei. In addition to revealing new aspects of trypanosome co-evolution within the vertebrate and invertebrate hosts, comparative genomic analysis with pathogenic trypanosomatids provides valuable new information that can be further explored with the aim of developing better diagnostic tools and/or therapeutic targets

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK.

BACKGROUND: A safe and efficacious vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), if deployed with high coverage, could contribute to the control of the COVID-19 pandemic. We evaluated the safety and efficacy of the ChAdOx1 nCoV-19 vaccine in a pooled interim analysis of four trials. METHODS: This analysis includes data from four ongoing blinded, randomised, controlled trials done across the UK, Brazil, and South Africa. Participants aged 18 years and older were randomly assigned (1:1) to ChAdOx1 nCoV-19 vaccine or control (meningococcal group A, C, W, and Y conjugate vaccine or saline). Participants in the ChAdOx1 nCoV-19 group received two doses containing 5 × 1010 viral particles (standard dose; SD/SD cohort); a subset in the UK trial received a half dose as their first dose (low dose) and a standard dose as their second dose (LD/SD cohort). The primary efficacy analysis included symptomatic COVID-19 in seronegative participants with a nucleic acid amplification test-positive swab more than 14 days after a second dose of vaccine. Participants were analysed according to treatment received, with data cutoff on Nov 4, 2020. Vaccine efficacy was calculated as 1 - relative risk derived from a robust Poisson regression model adjusted for age. Studies are registered at ISRCTN89951424 and ClinicalTrials.gov, NCT04324606, NCT04400838, and NCT04444674. FINDINGS: Between April 23 and Nov 4, 2020, 23 848 participants were enrolled and 11 636 participants (7548 in the UK, 4088 in Brazil) were included in the interim primary efficacy analysis. In participants who received two standard doses, vaccine efficacy was 62·1% (95% CI 41·0-75·7; 27 [0·6%] of 4440 in the ChAdOx1 nCoV-19 group vs71 [1·6%] of 4455 in the control group) and in participants who received a low dose followed by a standard dose, efficacy was 90·0% (67·4-97·0; three [0·2%] of 1367 vs 30 [2·2%] of 1374; pinteraction=0·010). Overall vaccine efficacy across both groups was 70·4% (95·8% CI 54·8-80·6; 30 [0·5%] of 5807 vs 101 [1·7%] of 5829). From 21 days after the first dose, there were ten cases hospitalised for COVID-19, all in the control arm; two were classified as severe COVID-19, including one death. There were 74 341 person-months of safety follow-up (median 3·4 months, IQR 1·3-4·8): 175 severe adverse events occurred in 168 participants, 84 events in the ChAdOx1 nCoV-19 group and 91 in the control group. Three events were classified as possibly related to a vaccine: one in the ChAdOx1 nCoV-19 group, one in the control group, and one in a participant who remains masked to group allocation. INTERPRETATION: ChAdOx1 nCoV-19 has an acceptable safety profile and has been found to be efficacious against symptomatic COVID-19 in this interim analysis of ongoing clinical trials. FUNDING: UK Research and Innovation, National Institutes for Health Research (NIHR), Coalition for Epidemic Preparedness Innovations, Bill & Melinda Gates Foundation, Lemann Foundation, Rede D'Or, Brava and Telles Foundation, NIHR Oxford Biomedical Research Centre, Thames Valley and South Midland's NIHR Clinical Research Network, and AstraZeneca

Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK

Background A safe and efficacious vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), if deployed with high coverage, could contribute to the control of the COVID-19 pandemic. We evaluated the safety and efficacy of the ChAdOx1 nCoV-19 vaccine in a pooled interim analysis of four trials. Methods This analysis includes data from four ongoing blinded, randomised, controlled trials done across the UK, Brazil, and South Africa. Participants aged 18 years and older were randomly assigned (1:1) to ChAdOx1 nCoV-19 vaccine or control (meningococcal group A, C, W, and Y conjugate vaccine or saline). Participants in the ChAdOx1 nCoV-19 group received two doses containing 5 × 1010 viral particles (standard dose; SD/SD cohort); a subset in the UK trial received a half dose as their first dose (low dose) and a standard dose as their second dose (LD/SD cohort). The primary efficacy analysis included symptomatic COVID-19 in seronegative participants with a nucleic acid amplification test-positive swab more than 14 days after a second dose of vaccine. Participants were analysed according to treatment received, with data cutoff on Nov 4, 2020. Vaccine efficacy was calculated as 1 - relative risk derived from a robust Poisson regression model adjusted for age. Studies are registered at ISRCTN89951424 and ClinicalTrials.gov, NCT04324606, NCT04400838, and NCT04444674. Findings Between April 23 and Nov 4, 2020, 23 848 participants were enrolled and 11 636 participants (7548 in the UK, 4088 in Brazil) were included in the interim primary efficacy analysis. In participants who received two standard doses, vaccine efficacy was 62·1% (95% CI 41·0–75·7; 27 [0·6%] of 4440 in the ChAdOx1 nCoV-19 group vs71 [1·6%] of 4455 in the control group) and in participants who received a low dose followed by a standard dose, efficacy was 90·0% (67·4–97·0; three [0·2%] of 1367 vs 30 [2·2%] of 1374; pinteraction=0·010). Overall vaccine efficacy across both groups was 70·4% (95·8% CI 54·8–80·6; 30 [0·5%] of 5807 vs 101 [1·7%] of 5829). From 21 days after the first dose, there were ten cases hospitalised for COVID-19, all in the control arm; two were classified as severe COVID-19, including one death. There were 74 341 person-months of safety follow-up (median 3·4 months, IQR 1·3–4·8): 175 severe adverse events occurred in 168 participants, 84 events in the ChAdOx1 nCoV-19 group and 91 in the control group. Three events were classified as possibly related to a vaccine: one in the ChAdOx1 nCoV-19 group, one in the control group, and one in a participant who remains masked to group allocation. Interpretation ChAdOx1 nCoV-19 has an acceptable safety profile and has been found to be efficacious against symptomatic COVID-19 in this interim analysis of ongoing clinical trials

The use of Sporothrix insectorum and Paecilomyces fumosoroseus against Boophilus microplus (Canestrini, 1887): in vitro assay and electronic microscopy

Em função do desenvolvimento de resistência aos diversos quimioterápicos existentes, o controle biológico vem sendo uma alternativa promissora no controle do Boophilus microplus. Neste trabalho foi avaliada a ação patogênica de Sporothrix insectorum e de Paecilomyces fumosoroseus nas diferentes fases do ciclo de vida do Boophilus microplus. Para isso, os fungos em estudo foram cultivados em meio de cultura apropriado, obtendo-se a suspensão estoque, a partir da qual foram preparadas suspensões nas concentrações de 105, 106, 107, 108, 109 conídios/mL para ambos os fungos. Os ovos e as larvas foram tratados por aspersão, e as partenóginas foram imersas nas diferentes suspensões de conídios. A patogenicidade dos fungos foi avaliada pela “performance reprodutiva” das carrapatas. O delineamento experimental foi realizado com cinco repetições para cada grupo de tratamento, nas diferentes concentrações fúngicas. Os fungos S. insectorum e P. fumosoroseus reduziram em 50,19% e 49,34%, respectivamente, a postura das partenóginas, quando utilizados na concentração de 108 conídios/mL. Em relação à eficácia, tais fungos alcançaram os valores de 82,99% e 82,93% na concentração de 108 conídios/mL e na de 109 conídios/mL, respectivamente. Sobre ovos de B. microplus, a atividade de P. fumosoroseus foi superior a de S. insectorum, reduzindo a eclodibilidade em 79,04% na concentração de 106 conídios/mL. S. insectorum reduziu tal parâmetro em apenas 37,92%, na concentração de 107 conídios/mL. No tratamento das larvas, os fungos avaliados não diferiram significativamente (P < 0,05) quanto à mortalidade das mesmas. As elétron-micrografias de varreduras, dos diferentes ínstares do B. microplus, evidenciam o poder predador dos fungos S. insectorum e P. fumosoroseus. Em face dos resultados obtidos, pode-se inferir que S. insectorum e P. fumosoroseus apresentaram ação deletéria sobre partenóginas de B. microplus in vitro, o que reforça a possibilidade do eventual emprego, desses fungos, no biocontrole desse importante ácaro.In function of the development resistance to the several existent quimiotherapics, biological control has being a promising alternative to the control of Boophilus microplus. In this work, the pathogenic action of Sporothrix insectorum and Paecilomyces fumosoroseus in the different stages of life cycle of Boophilus microplus was evaluated. The fungis in study were cultivated in appropriate culture medium and suspensions in the concentrations of 105, 106, 107, 108, 109 conidia/mL for both fungis were prepared, starling from stock suspension. The eggs and the larvaes were treated by spray, and the engorged tick were immersed in the different conidia suspensions. The pathogenicity of the fungis were appraised for the reproductive performance of the ticks. The experimental was accomplished with five repetitions for each treatment group, in the different fungal concentrations. The fungis S. insectorum and P. fumosoroseus reduced in 50,19% and 49,34%, respectively, the posture of the infected engorged female ticks, in the concentration 108 conidia/mL. In relation to effectiveness, the fungis S. insectorum and P. fumosoroseus, they reached the values 82,99%, in the concentration 108 conidia/mL, and 82,93% in the concentration 109 conidia/mL, for the respective fungis. In the eggs treatment with the S. insectorum and P. fumosoroseus, the fungi P. fumosoroseus presented a superiority with reduction of eclodibility in 79,04%, in the concentration 106 conidia/mL, while the S. insectorum, reduced in only 37,92%, in the concentration 107 conidia/mL. In the larvas treatment there were not significant differences in the larva mortality in both fungi. The electronic microscopy, in different stage of life of the B. microplus, showed the power predatory of the fungi S. insectorum and P. fumosoroseus. With these results, it can be inferred that S. insectorum and P. fumosoroseus presented deleterious action on engorged female of B. microplus in vitro, what reinforces your possibility eventual control of this important tick