Physiological plasticity in eucalyptus clones in the vegetative stage contributes to drought tolerance

With the expansion of eucalyptus crops to areas with severe water limitations,physiological studies involving eucalyptus clones to identify those that are tolerant to water stress become important.The objective of this study was to assess morphological and physiological responses by eucalyptus clones subjected to drought stress and rehydration.The experiment consisted of three eucalyptus clones:VC865,I224 and I144 and two water regimes:control and water stress followed by rehydration,with six replicates.Leaf water potential,gas exchange,maximum quantum efficiency of photo systemⅡand plant height and stem diameter were evaluated under drought stress and rehydration.After6 d of rehydration,the number of leaves,leaf area and dry mass of root,leaf,stem and their total were evaluated.All clones showed intense reduction of gas exchange during the drought stress period,and only VC865 and 1144 showed rapid recovery with 3 d of rehydration.Clone 1224 showed greater reduction in height,stem diameter,number of leaves,water potential at midday(Ψ_(w)_(Midday)),and maximum quantum efficiency of photosystemⅡ(F_(v)/F_(m)).Clones VC865and T144 showed lower reductions inΨ_(wMidday)and F_(v)/F_(m) under stress.VC865 had lower reductions in leaf number,leaf area and higher leaf dry mass,while clone I144 had higher height and lower reduction in root dry mass under.Both these clones showed higher water use efficiency with 3d of rehydration.These different phenotypic plasticities gave the clones VC865 and 1144 efficient mechanisms of acclimatization to stress and more drought tolerance,enhancing their greater capacity for recovery after stress,which allowed lower dry mass reduction.Clone 1224,however,was more susceptible to drought stress,undergoing greater physiological damage with only partial recovery during rehydration.

High aluminum concentration and initial establishment of Handroanthus impetiginosus : clues about an Al non-resistant species in Brazilian Cerrado

Cerrado soils are acidic and nutrient-poor,with high content of solubilized Al 3+.Plants growing in these conditions may display adaptations to cope with high aluminum concentrations especially during early developmental stages.We investigated leaf nutritional status,and photosynthetic and growth characteristics during the initial establishment of Handroanthus impetiginosus(Mart.Ex Dc.)Mattos,a secondary tree species distributed in the Brazilian Cerrado.Our goal was to understand leaf-level traits related to diff erent aluminum concentrations.H.impetiginosus plants were cultivated in four diff erent aluminum sulfate concentrations:0,1,2,and 4 mM Al,for 40 days.We performed analyses of growth,leaf gas exchange,chloroplast pigment content,and leaf mineral nutrients.We observed a linear increase of Al leaf content as a function of Al concentration in the nutrient solution.Plants grown in 1 mM Al showed a remarkable increase of K leaf content,net photosynthesis,stomatal conductance,and transpiration,while in 4 mM Al there were reductions of N,P,and K contents,gas exchange characteristics,and height.H.impetiginosus did not have mechanisms of avoidance,compartmentalization,or resistance to high Al concentrations.Indeed,this species showed a hormetic response,with low Al concentrations stimulating and high Al concentrations inhibiting plant responses.

Nest site selection and reproductive parameters of the threatened Atlantic Royal Flycatcher(Onychorhynchus swainsoni)and their significance for conservation

Background:Patterns of rarity can be explained by reproductive rates,levels of endemism,and habitat specificity,and knowledge on these parameters is important to understand the levels of vulnerability of each species and to formulate conservation strategies.Here,we studied nest-site selection and breeding biology of the Atlantic Royal Flycatcher(Onychorhynchus swainsoni),a poorly known vulnerable bird endemic to the Brazilian Atlantic Forest.Methods:We addressed nest site selection in three different levels:first,we searched for nests near and far from water to investigate whether birds could select water proximities to construct nests;second,we examined if they could select certain streams in detriment of others,and we analyzed the characteristics of used and non-used streams,and third,in streams in which nests were found,we addressed nest site selectivity by comparing a number of parameters between nest sites and random sites.Further,we provide information on breeding biology parameters related to annual fecundity.Results:During five breeding seasons,we found 23 nests in a well-preserved forest continuum.All of the nests were constructed above water,and they were found in streams that were about 4 m in width,instead of smaller streams with about 1.5 m in width.Modeling analyses revealed that within the used streams,nests were constructed in sites with lower vegetation density in relation to random points,while stream width,water speed,and canopy cover presented no significant correlation.Atlantic Royal Flycatchers in our study had a 22-day incubation period and 24 to 27-day nestling period.Overall nest survival was comparatively high(62%),but clutch size was small(N=2 eggs)and Along the nesting streams,we found an average of 1.62±0.07 breeding pairs/km.Conclusions:These data suggest that nesting habitat specificity and low annual fecundity are among the factors contributing to the rarity of the Atlantic Royal Flycatcher in large forest continuums and to its absence in fragmented environments.It reinforces the importance of large well-preserved forest continuums for the conservation of habitat specialist Atlantic Forest bird species.

10-Years Land Use Changes Decrease Landscape Integrity in a Brazilian Hydrographic Basin

Changes in land use associated with the suppression of native vegetation can greatly alter the landscape configuration, affecting biodiversity and environmental services availability. This study analyzes how changes in land use affect landscape patterns of vegetation remnant over a 10 year period. We quantified spatial landscape patterns throughout a hydrographic basin for the years 2002, 2008, 2010 and 2012, using nine landscape metrics. An indicator of integrity was used to details the transformation processes occurring in the basin that could be used to monitor the impact of landscape changes and its spatial patterning. Results showed that over this decade, extension of farming activities reduced the cover of native vegetation by 4.4%, with grassy-woody savanna, wooded savanna and forested savanna impacted especially strongly. Suppression of vegetation across this period reduced the size of fragments and their connectivity. The landscape fragmentation indicator indicated that the fragmentation pattern varied spatially, with the upland areas along river headwaters, being most fragmented. Areas of floodplains vegetation, belonged to the Pantanal Wetland, although in better integrity states, are the most threatened by current pressures of land use change. An intense recovery program for headwaters and aquifer recharge areas, as well as riparian forests, is recommended to avoid the future depletion of water production. Besides, we also recommend the maintenance and recovering of the connectivity of the current remaining patches of natural vegetation corridors and elaboration of specific laws that incoporate the consolidated scientific knowladge about wetland ecosystem functioning, like the Pantanal.

Characterization of Allele Diversity in a Microsatellite Locus: A Registry for Solenopsis invicta

The genus Solenopsis includes more than 100 species in the New World. When introduced, some species cause serious harm to the native wildlife and agriculture. Two forms of social organization are known in the genus, namely, monogyne and polygyne. Here, we present the genetic profile of a Solenopsis invicta Buren 1972 colony recorded in the central region of the city of São Paulo, São Paulo state, Brazil (23°33'37.18"S;46°42'48.66"W) to describe allele diversity. Eight microsatellite loci were used for the analysis of 30 worker ants. The results show the presence of seven alleles genotyped at the same microsatellite locus. Because this is an unusual finding, all of the alleles were sequenced, and surprisingly, an eighth allele was identified. These data suggest that the intracolonial genetic profile of fire ants must be investigated more frequently because there may be unexpected, albeit unknown, genetic patterns for S. invicta that can help inform better control and management programs.

The Bird Community in a Threatened Coastal Lagoon in Southeastern Brazil

We provide a list of bird species for Ribeira lagoon, a protected area in Rio de Janeiro, southeastern Brazil. Data were obtained in monthly surveys in points along a continuous transect, between August 2008 and July 2009, and 21 ad libitum observations. In total, 174 species were listed, including 121 land birds and 53 waterbirds. Of these, 11 are considered threatened at regional level. Waterbird richness was significantly higher in the dry season (April to September) than in the rainy season (October to March), whereas land bird richness remained constant. However, land bird richness varied throughout the year, with the highest value in February 2009 (77 species) and the lowest in May 2009 (41 species). The species listed account for 23% of the total of 745 bird species listed for Rio de Janeiro, and for 49% of 108 waterbirds recorded for the state.

Environmental Impacts of Rice Cultivation

This paper describes the major environmental aspects related to the cultivation of rice. Rice is one of the most important agricultural products and it is cultivated in almost all countries in the world. Its production requires usually large flooded areas. Under these conditions, many greenhouse gases are generated, such as carbon dioxide, methane, nitrogen oxides and its derivatives. Cultivation of rice is responsible by the release of relevant amounts of these gases and contributes decisively to global warming. In this sense, the major points described here are general environmental aspects, the mechanisms of production of greenhouse gases, bioremediation, mitigation using other techniques and possible improvements of the cultivation by fertilizers and chemicals.

Paleo-and Mesoarchean TTG-sanukitoid to high-K granite cycles in the southern São Francisco craton,SE Brazil

The generation of the continental crust is widely accepted to have taken place predominantly in the Archean,when TTG magmatism associated with greenstone-belt supracrustal succession development was typically followed by emplacement of high-K granites before crustal stabilization.This study focuses on the Campos Gerais complex(CGC),which is an Archean granite-greenstone belt lithological association in a tectonic window located in the southwesternmost portion of the São Francisco craton(SFC).The CGC is an important segment of Paleo-to Mesoarchean continental crust to be integrated into paleogeographic reconstructions prior to the transition into the Paleoproterozoic.This investigation reports field relationships,28 major and trace element compositions,U–Pb(zircon)geochronological results,and Hf and Sm–Nd isotope data for orthogneiss and amphibolite samples.The results indicate that the CGC records a complex Archean crustal evolution,where voluminous 2.97 Ga TTG tonalites and trondhjemites(ε_(Nd)(t)=-4.7;T_(DM)=3.24 Ga)were followed by 2.89 Ga sanukitoid tonalite production(ε_(Nd)(t)=-1.9;T_(DM)=3.02 Ga),broadly coeval with the development of the Fortaleza de Minas and Pitangui greenstone-belts.These events are interpreted to represent the initial stage of an important subduction-accretion tectonic cycle,which ended with the emplacement of 2.82–2.81 Ga high-K leucogranites and migmatization of the TTG-sanukitoid crust,with hybrid and two-mica,peraluminous compositions(ε_(Nd)(t)=-8.0 to-8.6;T_(DM)=3.57–3.34 Ga).The presence of inherited zircons with207Pb/206Pb ages of 3.08 Ga,3.29 Ga,3.55 Ga and 3.62 Ga indicates that the Mesoarchean tectonic processes involved reworking of Meso-to Eo-archean crust.Renewed TTG magmatism took place at ca.2.77 Ga represented by juvenile tonalite stocks(ε_(Nd)(t)=+1.0 to-1.5;T_(DM)=2.80–2.88 Ga)which intrude the TTG-greenstone belt association.Crustal stabilization was attained by 2.67 Ga,allowing for the emplacement of within-plate tholeiitic amphibolites(ε_(Nd)(t)=-3.1;T_(DM)=2.87 Ga).The CGC shows important tectonic diachronism with respect to other Archean terrains in the southern São Francisco craton,including an independent Meso-to Neoarchean crustal evolution.

Fast Radio Bursts as Crustal Dynamical Events Induced by Magnetic Field Evolution in Young Magnetars

We revisit in this work a model for repeating Fast Radio Bursts based of the release of energy provoked by the magnetic field dynamics affecting a magnetar’s crust.We address the basics of such a model by solving the propagation of the perturbation approximately,and quantify the energetics and the radiation by bunches of charges in the so-called charge starved region in the magnetosphere.The(almost)simultaneous emission of newly detected X-rays from SGR 1935+2154 is tentatively associated with a reconnection behind the propagation.The strength of f-mode gravitational radiation excited by the event is quantified,and more detailed studies of the nonlinear(spiky)soliton solutions are suggested.

MALDI-TOF MS Assessment to Identify Environmental Mycobacteria

Over the past few decades, there has been a significant increase in the number of mycobacterial species described. Currently, the genus?Mycobacterium?consists of 170 species. Most species are called nontuberculous mycobacteria (NTM) and are potentially or rarely pathogenic and ubiquitous. One of the main challenges in mycobacteriology is the rapid and precise identification of these microorganisms. In this work, we compared two protein extraction protocols for the identification of 38 reference strains and clinical isolates, representing 27 species, by mass spectrometry (MALDI-TOF MS) to subsequently use the best method for identifying environmental mycobacteria. The results obtained with reference strains and clinical isolates showed that protocol A was effective in identifying 92.1% of mycobacterial specimens at the species level and protocol B, 50%. Therefore, protocol A was evaluated for the rapid identification of 27 environmental mycobacterial isolates. These isolates were subjected to PCR-restriction enzyme analysis (PRA-hsp65). Two isolates were misidentified by PRA-hsp65, whereas MALDI-TOF MS was able to identify them correctly. The results were confirmed by?hsp65 and 16S rRNA gene sequencing. Mass spectrometry has the advantage of being a simpler and faster technique than PRA-hsp65, and our results showed that MALDI-TOF MS is a valuable tool for the identification of environmental mycobacterial isolates.

Dengue Climate Variability in Rio de Janeiro City with Cross-Wavelet Transform

Dengue is one of the most prominent tropical epidemic diseases present in the Rio de Janeiro city and Southeast part of Brazil, due to the widespread conditions of occurrence of the dengue vector, the mosquito Aedesaegypti, such as high-temperature days interlaced with afternoon or nocturnal rainstorms in summer. This work has the objective of investigating the relationships between variabilities of the El Ni?o-South Oscillation (ENSO) and greater epidemics of dengue in Rio de Janeiro city. To accomplish this goal, the analysis and signal decomposition by cross-wavelet transform (WT) was applied to obtain the cross variability associated with variations of power and phase of both signals by characteristic periods and along with the time series. Data considered in the analysis are (the decimal logarithm of normalized value) of the monthly available notifications of dengue worsening, provided by the public health system of Brazil, and the Southern Oscillation Index (SOI) Ni?o 3.4 data, provided by the National Oceanic and Atmospheric Administration (NOAA), in the period 2000-2017. A maximum cross-wavelet power close to 0.45 was obtained for the representative period of 1 year and also to periods between 3 and 4 years, associated with the positive phase of the SOI index (i.e. , La Ni?a) or with a transition to the positive phase. The evolution of the combined variability of SOI and dengue can be expressed by progressive differences in phase along the time, eventually resulting in yielding phases (i.e., La Niña-Dengue epidemic).

Flight performance and wing morphology in the bat Carollia perspicillata:biophysical models and energetics

Studies on functional performance are important to understand the processes responsible for the evolution of diversity.Morphological trait variation within species influences the energetic cost of locomotion and impacts life history traits,with ecological and evolutionary consequences.This study examined wing morphology correlates of flight performance measured by energetic expenditure in the Seba’s short-tailed bat,Carollia perspicillata.In the flight experiments,nature caught bats(59 females,57 males)were allowed to fly for 3 min in a room.After each flight,thermographic images were taken to measure body temperature,and biophysical models were used to calculate sensible heat loss as a measure of energetic expenditure.Wing morphological traits were measured for each individual and associated with heat loss and power required to fly on performance surfaces.Wing morphological traits explained 7-10%of flight energetic cost,and morphologies with the best performance would save the energy equivalent to 9-30%of total daily requirements.The optimal performance areas within the C.perspicillata morphospace were consistent with predicted selection trends from the literature.A trade-off between demands for flight speed and maneuverability was observed.Wing loading and camber presented sexual dimorphism.These morphological differences are likely associated with more economical but less maneuverable flight in females,leading them to fly more often in open areas along the forest edge.Our findings demonstrate how small scale changes in wing morphology can affect life history strategies and fitness.

Species richness and density evaluation for plants with aggregated distributions:fixed vs.variable area methods

Aims Knowledge of species richness is of prime importance to both basic and applied aspects of ecological studies.However,quantifying plant species richness in the tropics is potentially time-consuming because of high species diversity.Plant species richness estimates are also frequently biased,because many rare species are not detected.to address these problems,the use of a variable area method has been proposed as an alternative to fixed area methods,but its appli-cability to plants with aggregated distributions has been questioned based on simulation studies.We use empirical data to compare the efficiency and accuracy of a variable area method and a fixed area method for estimating species richness,density and basal area for plants with aggregated distributions,using palms as a model taxon.Methods Adult palms were sampled in twenty 10×30 m transects in an Atlantic Forest in Rio de Janeiro state,Brazil.All individuals were considered in the fixed area method,while in the variable area method only the first six adults in each transect were sampled;in this case,transect length was defined according to the distance of the sixth adult from the beginning of the transect.When fewer than six individuals were observed in a given transect,transect length was extended up to 50 m to search for additional individuals.the efficiency of both methods was compared based on species rarefaction curves,using the chao 1 statistic(for abundance data).For each species we calculated mean density per transect and basal area,according to each sampling method.Sampling effort in terms of the number of individual plants and the area necessary to characterize maximum species richness in each sampling method,as well as mean time taken to sample a single transect,were compared as measures of efficiency.Important findings An accurate estimate of species richness was achieved using both methods,but in the variable area method,a quarter of the number of individuals and half the area was sufficient to characterize maximum species richness.Density and basal area did not differ between meth-ods for any of the species studied.In the fixed area method sampling effort was 90 min per transect,whereas in the variable area method it was 30 min per transect.the variable area method,with its faster assessment of palm species richness,should facilitate greater spatial representativeness by making it easier to sample a larger number of plots at different spatial scales.We thus find sufficient evidence to recommend the variable area method for rapid and robust evaluations of species richness for palms with aggregate distributions,as well as for other plants with similar spatial patterns,in tropical forests.

Redback/Black Widow Systems as progenitors of the highest neutron star masses and low-mass Black Holes

The long-standing problem of the maximum mass that can be achieved by the compact objects,with clear implications for the equation of state of matter above the nuclear saturation density(see ref.[1]and references therein),is receiving a new twist with the latest data from binary systems and NS-NS merging events.Long ago,double neutron stars systems(DNS)data installed the idea of a"canonical"mass of^1.4 M_⊙,but later work provided evidence for heavier objects with increasing degree of confidence,and it became clear that at least a second"mass scale"had to be present[2].