The intraindustry effects of going concern audit reports

This paper investigates the effect of a going concern opinion (GCO) on the equity value of the announcing firm’s competitors. On average, GCOs increase the value of a value-weighted portfolio of rivals by 0.37% at the event date. This positive effect is significantly larger when the announcing firm is relatively more profitable, the industry is more concentrated, and when rivals and event firms have distinct assets in place and growth opportunities. Additional tests reveal that such competitive effect is not a mere short-term phenomenon as investors can earn up to 1.54% on a risk-adjusted basis over the first postGCO month. This finding is especially interesting as we show that for the industry rivals the one-year and six-month preGCO riskadjusted equity returns are, on average, strongly negative. Our results highlight the impact of mandatory accounting information on market prices at both the firm and industry levels.Audit reports; Going concern; Competitive effect; Contagion effect.

Growth analysis of in vitro-regenerated chestnuts during the acclimatization stage using elevated CO2

Great advances have been made but some cultured plantlets still having a poor performance during the ex vitro stages and more specifically during the acclimatization and the nursery establishment stages. The problem is highly complex and requires the fast adaptation of plants growing in artificial conditions when transferred to the natural conditions. Until now, there is no consensus on the better strategy to obtain a higher efficiency of the propagation protocols while optimising acclimatization success. In this study we present the results of growth analysis of in vitro-regenerated chestnut hybrid plantlets (Castanea sativa x C. crenata), during the acclimatization stage, using two CO2 concentrations (350 µLL-1 and 700 µLL-1) at 250 µmol m- 2 s-1 as irradiance level (PPFD). Elevated CO2 did not affect the survival rate and it was susceptible to increase progressive autotrophy, expressed by a significant increase in relative growth, shoot/root ratio and leaf area ratio (LAR). For both CO2 concentrations, the plants are successfully acclimatized and they are in good conditions to be transferred to a greenhouse to continue their development for the rest of the season, and in the next winter/spring they can go to the field. The plants under elevated CO2 showed a higher stomatal frequency but the new leaves developed at the end of acclimatization revealed a gradual normal stomatal morphology and they reduced the stomatal frequency. Their morphology showed an effective water loss control, which is one of the most important problems during this critical phase of the autotrophic competence acquiring process. The net photosynthesis rate (A) was similar in both treatments but the plants acclimatized at elevated CO2 showed an increase in maximum photosynthetic rate (Amax), and this can lead to a better physiological development. The different analysed leaf types showed a marked increment of the maximum photosynthetic rate as the new leaves developed during the acclimatization stage. Net photosynthesis rate and the maximum photosynthetic rate are light dependent, and are positively affected by the highest irradiance level. We think that the gains that we have achieved with the use of elevated CO2 can be more significant if a higher light intensity can be used instead because they have a better response capacity to an increment of the level of irradiance

Avaliação de parâmetros fotossintéticos em microplantas de Castanheiro durante a fase de aclimatização.

O objetivo deste trabalho foi realizar um estudo comparativo em microplantas de castanheiro com dois sistemas de expressão e desenvolvimento radicular, in vitro e ex vitro, e com duas intensidades luminosas (150 e 250 μmol m-2 s-1) durante a aclimatização, e a sua influência no desenvolvimento das microplantas durante esta fase, através da quantificação de parâmetros fotossintéticos. A concentração de clorofilas, após os tratamentos de aclimatização, dependeu quer do tipo de sistema radicular que as plantas possuíam no início da aclimatização, quer do regime luminoso a que as plantas estiveram submetidas. As plantas com enraizamento in vitro e aclimatizadas sob menor irradiância foram as que apresentaram valores superiores para a clorofila total (7,74 mg g-1ps), mas com o valor mais baixo na razão entre clorofila a/b (2,7). Quando comparamos os valores registados para os parâmetros fotossintéticos das plantas dos diferentes tratamentos, verificamos que as taxas de fotossíntese aparente vão gradualmente aumentando à medida que as novas folhas se vão desenvolvendo (0,75 μmol CO2 m-2 s-1 nas folhas persistentes e 3,43 μmol CO2 m-2 s-1 na folha 3 das plantas aclimatizadas a 250 μmol m-2 s-1). O mesmo acontece na capacidade fotossintética (3,93 μmol O2 m-2 s-1 nas folhas persistentes e 7,87 μmol O2 m-2 s-1 na folha 3 das plantas aclimatizadas a 250 μmol m-2 s-1). Estes valores foram tendencialmente superiores nas plantas com enraizamento ex vitro e aclimatizadas a maior irradiância, pelo que a um melhor sistema radicular e uma maior disponibilidade luminosa correspondeu um acréscimo na competência fotossintética, o que resultou num melhor desenvolvimento morfofisiológico das plantas.Abstract The aim of this study was to conduct a comparative study in chestnut microplants with two systems of expression and root development, in vitro and ex vitro, and with two light intensities (150 and 250 μmol m-2 s-1) during acclimatization, and its influence on the development of microplants during this phase, through the quantification of photosynthetic parameters. The chlorophyll concentration after acclimatization treatments depended on both type of root system that the plants had at the beginning of acclimatization, whether the light intensity to which the plants were subjected. Plants with roots in vitro and acclimatized under lower irradiance showed the higher values for total chlorophyll (7.74 mg g-1ps), but with the lowest value of the ratio of chlorophyll a/b (2.7). When the values recorded for the photosynthetic parameters of plants of different treatments were compared, we found that the rates of apparent photosynthesis gradually increasing as the new leaves are developed (0.75 μmol CO2 m-2 s-1 in persistent leaves and 3.43 μmol CO2 m-2 s-1 on leaf 3 on plants acclimatized to 250 μmol m-2 s-1). The same happens in photosynthetic capacity (3.93 μmol O2 m-2 s-1 in persistent leaves and 7.87 μmol O2 m-2 s-1 on leaf 3 of plants acclimatized to 250 μmol m-2 s-1). These values were higher in plants with ex vitro rooting and acclimatization to higher irradiance, so a better root system availability and a higher light availability, corresponding to an increase in the photosynthetic ability, resulting in a better morphophysiological plant development.info:eu-repo/semantics/publishedVersio

Effects of elevated CO2 on acclimatization of in-vitro regenerated chestnuts

Comunicação oral apresentada no II International Symposium on Acclimatization and Establishment of Micropropagated Plants que decorreu em 2004 em Cancún, no México.In this study we present the results of growth analysis of in vitro-regenerated chestnut hybrid plantlets (Castanea sativa x C. crenata), during the acclimatization stage, using two CO2 concentrations (350 and 700 μLL-1) at 250 μmol m-2 s-1 as irradiance level (PPFD). Elevated CO2 did not affect the survival rate and it was susceptible to increase progressive autotrophy, expressed by a significant increase in relative growth, shoot/root ratio and leaf area ratio (LAR). The plants under elevated CO2 showed an higher stomatal frequency but the new leaves developed at the end of acclimatization revealed a gradual normal stomatal morphology and they reduced the stomatal frequency. Their morphology showed an effective water loss control which is one of the most important problem during this critical phase of the autotrophic competence acquiring process. The net photosynthesis rate was similar in both treatments but the plants acclimatized at elevated CO2 showed an increase in maximum photosynthetic rate (Amax), and this can lead to a better physiological development. We think that the gains that we have achieved with the use of elevated CO2 can be more significant if an higher light intensity can be used instead because they have a better response capacity to an increment of the level of irradiance

Estudos de propagação in vitro, caracterização e valorização de carqueja (Pterospartum tridentatum (L.) Willk)

The Pterospartum tridentatum (L.) Willk is widely used as medicinal plant for the treatment of digestive tract diseases and diabetes and for culinary purposes, however, characterization studies on this plant extracts are scarce. This work aimed to develop methodologies for micropropagation of this species and carry out characterization and application of the aqueous extracts. This study represents the first comparison analysis of extracts obtained from wild plants and aerial parts of plants in vitro multiplication. Micropropagation was very effective on large scale propagation with high multiplication rates. Aqueous extracts showed a good performance, high levels of phenolic compounds and antioxidant activity both in wild plants and in micropropagation. Phenolic profiles in in vitro shoots are very similar to extracts of wild plants during vegetative rest. The extracts revealed no antifungal activity, but nevertheless evidenced inhibition for some microorganisms. Within the monosaccharides, glucose is the predominant sugar in wild plants, since in the in vitro shoots uronic acids are the main components. An interesting result was the higher molar percentages of rhamnose and uronic acids detected on in vitro shoots compared to wild plants, which can make the in vitro plant material very useful to obtain these compounds. The application of chitosan bioactive coatings incorporating extracts has improved post-harvest storage capacity in cherry. The results allow propose these methodologies for obtaining extracts with bioactive properties from micropropagated material without depleting natural resources

Laboratório de Biologia.

Laboratório de Biologia.info:eu-repo/semantics/publishedVersio

Semi-active vibration control of a non-collocated civil structure using evolutionary-based BELBIC

A buildings resilience to seismic activity can be increased by providing ways for the structure to dynamically counteract the effect of the Earth’s crust movements. This ability is fundamental in certain regions of the globe, where earthquakes are more frequent, and can be achieved using different strategies. State-of-the-art anti-seismic buildings have, embedded on their structure, mostly passive actuators such as base isolation, Tuned Mass Dampers (TMD) and viscous dampers that can be used to reduce the effect of seismic or even wind induced vibrations. The main disadvantage of this type of building vibration reduction strategies concerns their inability to adapt their properties in accordance to both the excitation signal or structural behaviour. This adaption capability can be promoted by adding to the building active type actuators operating under a closed-loop. However, these systems are substantially larger than passive type solutions and require a considerable amount of energy that may not be available during a severe earthquake due to power grid failure. An intermediate solution between these two extremes is the introduction of semi-active actuators such as magneto–rheological dampers. The inclusion of magneto–rheological actuators is among one of the most promising semi-active techniques. However, the overall performance of this strategy depends on several aspects such as the actuators number and location within the structure and the vibration sensors network. It can be the case where the installation leads to a non-collocated system which presents additional challenges to control. This paper proposes to tackle the problem of controlling the vibration of a non-collocated three-storey building by means of a brain–emotional controller tuned using an evolutionary algorithm. This controller will be used to adjust the stiffness coefficient of a magneto–rheological actuator such that the building’s frame oscillation under earthquake excitation, is mitigated. The obtained results suggest that, using this control strategy, it is possible to reduce the building vibration to secure levelsinfo:eu-repo/semantics/publishedVersio

Natural extracts from Pterospartum tridentatum at different vegetative stages: extraction yiels, phenolic content and antioxidant activity

The aerial parts of Pterospartum tridentatum, a wild growing species in Portugal used in traditional medicine and gastronomy, were harvested at different stages (vegetative phase, flowering phase and beginning of dormancy) in two locations in Portugal (Malcata and Gardunha mountains), and the respective aqueous extracts have been studied. The influence of the seasonal variation in the extraction yield, total phenolic content and antioxidant activity was evaluated. The extraction was carried out in boiling water in consecutive steps. After each step, the aqueous extract was separated and fresh water was added maintaining the same plant material. The procedure was repeated seven times, within an overall time period of 180 minutes. Higher extraction yields were achieved with plant stems collected at the vegetative phases, either from Malcata or Gardunha regions. The total phenolic content of the extracts from Malcata plants ranged from 273 mg to 400 mg gallic acid equivalent/g dry matter, which was quite similar to that determined for extracts from Gardunha (245 to 394 mg gallic acid equivalent/g dry matter). The antioxidant activity was determined by the radical scavenging activity method using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH). The greatest radical scavenging activity was observed in the flowers extracts, even though all extracts produced presented a good antioxidant activity. Furthermore, the antioxidant activity was not affected by the exposure of the plant material at 100ºC for long periods of time (180 min). The results show that Pterospartum tridentatum has a great potential to be used as a new source of natural antioxidants for the food industry

Identificação de compostos bioativos em plantas silvestres e plantas in vitro de Pterospartum tridentatum (L.) Willk.

Identificação de compostos bioativos em plantas silvestres e plantas in vitro de Pterospartum tridentatum (L.) Willk.info:eu-repo/semantics/publishedVersio

Atividade antioxidante e antimicrobiana de extratos de plantas de Pterospartum tridentatum (L.) Willk. in vitro e silvestres

Atividade antioxidante e antimicrobiana de extratos de plantas de Pterospartum tridentatum (L.) Willk. in vitro e silvestres.info:eu-repo/semantics/publishedVersio