Perspectivas das ciências da biodiversidade no Brasil

A temática da biodiversidade no Brasil alcançou um ponto crítico onde, por um lado, a ciência da biodiversidade aumenta em quantidade e em qualidade, enquanto que por outro, a destruição de habitats nos grandes biomas brasileiros se mantém em taxas alarmantes. Eu defendo que este paradoxo, numa perspectiva científica, tenha dois princípios centrais nos quais cientistas talvez devessem se concentrar. Primeiramente, embora as ciências relacionadas à biodiversidade no Brasil sejam de alto padrão se comparadas com o que é produzido no resto do mundo, o país ainda não detém a ponta do conhecimento em nenhuma destas ciências. E segundo lugar, a riqueza de informações produzida por fortes programas de pesquisa - como o Biota/Fapesp, ao qual este número especial de Scientia Agricola é dedicado - está apenas começando a auxiliar tomadores-de-decisão a aumentar a precisão e a qualidade das decisões referentes ao meio ambiente, mas ainda há muito a ser feito a este respeito. Portanto, eu discuto alguns dos tópicos acerca da biodiversidade que permanecem controvertidos e demandam rápido crescimento científico. Eu proponho que atacando estes temas o Brasil talvez possa vir a alcançar a ponta do conhecimento em médio prazo. Em seguida, discuto como podem ser aprimoradas as vias de comunicação entre cientistas e tomadores-de-decisão e o público em geral, enfatizando como um forte programa educacional - que cubra do jardim de infância à pós-graduação - será imprescindível para solucionar os dois problemas acima e definitivamente romper com o paradoxo conhecimento da biodiversidade vs. destruição da biodiversidade.Biodiversity issues in Brazil have reached a critical point. On one hand, biodiversity science is increasing in quality and quantity, however on the other, habitat destruction in all major biomes still maintain alarmingly high rates. This paradox, from a scientific perspective, has two central tenets that scientists should focus on. First, although science related to biodiversity is of high standard in Brazil as compared to that of peers in the world, it is still not at the leading edge of research. Second, the wealth of information built up by strong research programmes, such as Biota/Fapesp - to which this special issue of Scientia Agricola is dedicated - is beginning to help decision-makers to improve precision and quality of their decisions concerning the environment, but still much is left to be done in this respect. Therefore, I discuss some of the biodiversity issues that remain controversial and demand fast scientific growth. Tackling them Brazil may finally reach the leading edge of biodiversity research. Finally, I discuss how communication between scientists and decision-makers and the general public may be improved, highlighting how a strong education project is urgently needed from kindergarten to graduate programmes in order to solve the two problems above mentioned and definitely crack the paradox biodiversity knowledge vs. biodiversity destruction

The effects of ontogeny and environmental oscillations on plant responses to oxygen deprivation

The effects of ontogeny and environmental oscillations on plant responses to oxygen deprivation were investigated for a wide spectrum of species, ranging from agricultural to forestry crops, and from temperate to tropical plants. The extent to which hypoxia- or anoxia-tolerance were affected by ontogeny and environmental oscillations, was assessed mainly through changes in survival and growth and physiological parameters such as respiratory activity, ethanol production and carbohydrate depletion. Anoxia-tolerance of germinating seeds of chickpea (Cicer arietlnum L.) was found to vary, even within the earlier stages of germination, according to the length of the aerobic imbibition period previous to the anoxic shock. The notable fact was that 6 minutes of seed aerobic imbibition prior to anoxic treatment was sufficient to significantly increase post-anoxic survival after 4 days anoxia, compared to seeds not allowed to previously imbibe aerobically. These survival results were mirrored by the significant increase in the oxygen uptake by the embryos of seeds which were allowed to imbibe aerobically for 2 hours prior to anoxia, compared to the embryos of anaerobically imbibed seeds. Germination stage also affected the response of barley (Hordeum vulgare L.) to washing under anoxia, a treatment used to investigate membrane stability and other factors associated with anoxic injury. Temperature, frequency of washing and nutrients present in the washing solution also affect the post-anoxic responses of barley. Daily washing of seedlings under anoxia was often detrimental to post-anoxic survival. One washing only, at the end of the anoxic period, often enhanced survival. This positive effect seemed to be more linked to protection against plasmamembrane leakage due to calcium ions present in the washing solution than to removal of anaerobically-produced potentially toxic volatiles. Two Brazilian tree species were also studied. The seeds of Parkia pendula (Willd.) Benth. ex. Walp., a species typically present in unflooded areas in the Amazon, were still able to germinate after seven months submergence. P.pendula one-month old seedlings, however, did not survive longer than one month flooding, which can be a considerable disadvantage in the ca. six-month long flooding period of the Amazon floodplains. However, adult trees can still be found, although rarely, in flooded areas. The possible strategies involved in an eventual establishment of P.pendula individuals in flooded areas of the Brazilian Amazon are discussed. A contrast is drawn between the responses to flooding of this species and flood-tolerant Parkia discolor. Enterolobium contortisiliquum (Veil.) Morong, is a tree species which is present in both the dry soils of the cerrados (neotropical savannas) in Central Brazil and in the flood-prone Gallery Forests. This species showed considerable tolerance to flooding and drought, as reflected by the various morphological and metabolic adaptations observed in response to these stresses. The role of the xylopodium, a rigid wood tuber, in such tolerance to flood and drought stresses is discussed. Water-stressed roots of some crop species studied presented higher ethanol levels than control plants. Additionally, these same drought-treated roots showed a considerable amount of shrinkage compared to control roots, as measured by root diameter. It is argued that drought causes root shrinkage, which possibly reduces ability of such roots to capture oxygen and results in hypoxia in the tissues and consequent increase in ethanol production. This hypothesis of drought-induced hypoxia is compared with several recent findings in the literature, and is discussed as a possible factor which allows drought, under specific circumstances, to acclimatise plants to a subsequent flooding. From preliminary experiments with alternation of flooding and drought in Eucalyptus species, it appeared that a previous stress affects a plant's response to a subsequent stress. This effect was not always negative, and in E.regnans a five-week drought allowed a subsequent 3-fold increase in flooding survival. This experiment, however, needs to be repeated in order to confirm these results. A common cause for anaerobic injury seems to be unlikely for the diverse plants studied, and anoxia survival often seemed to be related to a combination of morphological and metabolic adaptations. A critical reflection on the risks of labelling plants as tolerant or sensitive to oxygen deprivation is provided, as well as a discussion on the perspectives of applied research which may further the development of ecophysiological theory

Study of the reflection spectrum of the accreting neutron star GX 3+1 using XMM-Newton and INTEGRAL

Broad emission features of abundant chemical elements, such as Iron, are commonly seen in the X-ray spectra of accreting compact objects and their studies can provide useful information about the geometry of the accretion processes. In this work, we focus our attention on GX 3+1, a bright, persistent accreting low mass X-ray binary, classified as an atoll source. Its spectrum is well described by an accretion disc plus a stable comptonizing, optically thick corona which dominates the X-ray emission in the 0.3-20 keV energy band. In addition, four broad emission lines are found and we associate them with reflection of hard photons from the inner regions of the accretion disc where doppler and relativistic effects are important. We used self-consistent reflection models to fit the spectra of the 2010 XMM-Newton observation and the stacking of the whole datasets of 2010 INTEGRAL observations. We conclude that the spectra are consistent with reflection produced at ~10 gravitational radii by an accretion disc with an ionization parameter of xi~600 erg cm/s and viewed under an inclination angle of the system of ~35{\deg}. Furthermore, we detected for the first time for GX 3+1, the presence of a powerlaw component dominant at energies higher than 20 keV, possibly associated with an optically thin component of non-thermal electrons.Comment: Accepted to appear on MNRAS, 9 pages, 5 figur

Broad-band spectral analysis of the accreting millisecond X-ray pulsar SAX J1748.9-2021

We analyzed a 115 ks XMM-Newton observation and the stacking of 8 days of INTEGRAL observations, taken during the raise of the 2015 outburst of the accreting millisecond X-ray pulsar SAX J1748.9-2021. The source showed numerous type-I burst episodes during the XMM-Newton observation, and for this reason we studied separately the persistent and burst epochs. We described the persistent emission with a combination of two soft thermal components, a cold thermal Comptonization component (~2 keV) and an additional hard X-ray emission described by a power-law (photon index ~2.3). The continuum components can be associated with an accretion disc, the neutron star (NS) surface and a thermal Comptonization emission coming out of an optically thick plasma region, while the origin of the high energy tail is still under debate. In addition, a number of broad (~0.1-0.4 keV) emission features likely associated to reflection processes have been observed in the XMM-Newton data. The estimated 1.0-50 keV unabsorbed luminosity of the source is ~5x10^37 erg/s, about 25% of the Eddington limit assuming a 1.4 solar mass NS. We suggest that the spectral properties of SAX J1748.9-2021 are consistent with a soft state, differently from many other accreting X-ray millisecond pulsars which are usually found in the hard state. Moreover, none of the observed type-I burst reached the Eddington luminosity. Assuming that the burst ignition and emission are produced above the whole NS surface, we estimate a neutron star radius of ~7-8 km, consistent with previous results.Comment: Accepted for publication in MNRAS; 12 pages, 9 figures, 2 table

Correlazione tra alitosi e trattamento ortodontico? Questioni di corretti stili di igiene orale. Case report

Nel trattamento delle malocclusioni, la terapia ortodontica fissa è la più suffragata (Fig. 1a). Anche se uno degli obiettivi del trattamento ortodontico in soggetti con malocclusioni è migliorare oltre che la funzione anche la salute parodontale, la terapia stessa può provocare una maggiore incidenza di infiammazioni con conseguente sanguinamento gengivale, recessioni e la ritenzione di placca1. Poiché la rugosità superficiale e l’energia libera di superficie sono correlati con l’accumulo di placca2, la presenza di un dispositivo ortodontico aumenta tale deposito con conseguente infiammazione gengivale in soggetti con malocclusione3. È ben documentato che il trattamento ortodontico con apparecchi fissi si accompagni a un aumentato rischio di gengiviti dovuto all’accumulo di placca batterica attorno agli attacchi2,3 (Figg. 1b-1d). L’alitosi di origine orale è associata con il metabolismo microbico sul dorso lingua, nella saliva e nella placca dentale4 (Figg. 2a-2b); dunque l’intensità dell’alito cattivo è significativamente associata con la quantità di composti volatili endorali contenenti solfuro. Questi composti sono prodotti da batteri gram-negativi orali che metabolizzano aminoacidi presenti nella dieta e producono gas, come solfuro di idrogeno (H2S)5. Ci sono generalmente tre metodi accettati per la valutazione del cattivo odore orale: misurazione organolettica, gas cromatografia (GC) e monitoraggio solfuro portatile6. Studi hanno dimostrato la correlazione a breve termine del cattivo odore orale nella terapia ortodontica fissa, mentre effetti a lungo termine non sono ancora stati documentati7-10

ARE GREEN AREAS ALL THE SAME? THE IMPORTANCE OF CONSIDERING TYPOLOGIES OF URBAN GREEN AREAS TO EVALUATE THEIR BENEFITS IN CURITIBA

Áreas verdes urbanas (AVU) são espaços livres de edificações, com predominância de cobertura vegetal, que geram serviços ecossistêmicos importantes nas cidades, como a melhoria microclimática, a segurança hídrica, e a saúde física e mental dos seus habitantes. Geralmente, as AVU são consideradas como um só componente em estudos sobre a floresta urbana, embora possam ter coberturas do solo e qualidade da vegetação diferentes entre si. Esta pesquisa buscou caracterizar tipologias de áreas verdes usando o índice de vegetação por diferença normalizada (NDVI) para investigar se existe distinção entre elas. Para isso, Curitiba foi selecionada como área de estudo, tendo 18 tipologias de áreas verdes. O NDVI do município, das áreas verdes em conjunto, e de cada tipologia foi calculado com base em imagem LANDSAT-8 e classificado em água, não-vegetação, vegetação gramínea e ou arbustiva, vegetação arbórea esparsa, ou vegetação arbórea densa. Uma análise estatística descritiva e um teste t de igualdade de médias também foram realizados. Os resultados demonstraram diferenças entre a maioria das tipologias, com alta amplitude entre valores mínimos, máximos e médios, estes diferentes entre si na maioria dos casos (72,50%). A proporção ocupada por cada classe de NDVI variou bastante entre as tipologias, principalmente para vegetação gramínea e ou arbustiva (0,00% a 72,22%) e arbórea esparsa (5,26% a 80,00%). Por isso, destaca-se a importância de se conhecer e qualificar a vegetação de diferentes áreas verdes em estudos futuros.Urban green areas (UGA) are open spaces, predominantly with vegetation cover, which generate important ecosystem services to cities, such as microclimate improvement, water security, and physical and mental health of its inhabitants. Usually, UGA are considered as one in urban forest studies, although their land cover and vegetation quality may differ from each other. This research aimed to characterize typologies of urban green areas using the normalized difference vegetation index (NDVI) to investigate whether there is a distinction between them. For this, Curitiba was selected as the study area, a city with 18 types of green areas. The NDVI of the municipality, of the green areas altogether, and of each typology was calculated based on a LANDSAT-8 image and classified as water, non-vegetation, grass and or shrub cover, sparse tree cover, or dense tree cover. In addition, descriptive statistical analysis and t-test for equality between means were performed. Results showed differences between most typologies, with high amplitude between minimum, maximum, and mean values, these differing from each other in most cases (72.50%). The proportion occupied by each class also varied between typologies, mainly for grass and or shrub cover (0.00% to 72.22%) and sparse tree cover (5.26% to 80.00%). Therefore, the importance of knowing and qualifying the vegetation of different green areas in future studies is highlighted

Searching for solutions to the conflict over Europe's oldest forest

The Białowieża Forest World Heritage site is one of the last remaining primeval forests in lowland Europe and is a refuge for European Bison (Bison bonasus), the largest land mammal on the continent (Table 1)

Hygienic and sensory quality factors affecting the shelf-life of Fruhe (Casu axedu) traditional Sardinian fresh cheese

A study was conducted to evaluate the dura- bility of the traditional fresh soft cheese Fruhe manufactured in Sardinia either from goats’ or sheep’s milk. Four farmstead cheese-making plants were visited three times during the Fruhe cheese-making season. During each visit environmental samples were collected from food contact and non-food contact sur- faces in order to evaluate the presence of Enterobacteriaceae, Escherichia coli, Pseudomonas spp. and Listeria spp. In a total of 60 environmental samples, Escherichia coli and Listeria spp. were never detected, while contamination with Enterobacteriaceae and Pseudomonas spp. was observed respectively in 48% and 43% of samples. The microbiological profile of 48 Fruhe cheese samples was assessed at different time points during the product shelf-life. Aerobic mesophilic bacteria, Enterobacteriaceae, E. coli, Pseudomonas spp., Bacillus cereus and Listeria monocytogenes were investigated at 0, 7, 14 and 21 days after production. E. coli, L. monocytogenes and B. cereus were never detected in the product. Enterobacteriaceae contamination was observed, showing decreasing levels over time. Pseudomonas spp. was recovered in only two Fruhe samples (3.3%) at day 0. Sensory analysis was also conducted using a triangle test to determine whether a difference between Fruhe samples at 14 and 21 days of shelf-life exists. Based on the evolution of the microbiological profile and the sensory attributes observed in the present study, it is reasonable to assume that the product shelf-life can be feasibly extended up to 21 days