Selective logging is well-recognized as an effective practice in sustainable forest management.However,the ecological efficiency or resilience of the residual stand is often in doubt.Recovery time depends on operation...Selective logging is well-recognized as an effective practice in sustainable forest management.However,the ecological efficiency or resilience of the residual stand is often in doubt.Recovery time depends on operational variables,diversity,and forest structure.Selective logging is excellent but is open to changes.This may be resolved by mathematical programming and this study integrates the economic-ecological aspects in multi-objective function by applying two evolutionary algorithms.The function maximizes remaining stand diversity,merchantable logs,and the inverse of distance between trees for harvesting and log landings points.The Brazilian rainforest database(566 trees)was used to simulate our 216-ha model.The log landing design has a maximum volume limit of 500 m3.The nondominated sorting genetic algorithm was applied to solve the main optimization problem.In parallel,a sub-problem(p-facility allocation)was solved for landing allocation by a genetic algorithm.Pareto frontier analysis was applied to distinguish the gradientsα-economic,β-ecological,andγ-equilibrium.As expected,the solutions have high diameter changes in the residual stand(average removal of approximately 16 m^(3) ha^(-1)).All solutions showed a grouping of trees selected for harvesting,although there was no formation of large clearings(percentage of canopy removal<7%,with an average of 2.5 ind ha^(-1)).There were no differences in floristic composition by preferentially selecting species with greater frequency in the initial stand for harvesting.This implies a lower impact on the demographic rates of the remaining stand.The methodology should support projects of reduced impact logging by using spatial-diversity information to guide better practices in tropical forests.展开更多
A possible way to increase thermal conductivity of working fluids, while keeping pressure drop at acceptable levels, is through nanofluids. Nanofluids are nano-sized particles dispersed in conventional working fluids....A possible way to increase thermal conductivity of working fluids, while keeping pressure drop at acceptable levels, is through nanofluids. Nanofluids are nano-sized particles dispersed in conventional working fluids. A great number of materials have potential to be used in nanoparticles production and then in nanofluids;one of them is Multi-Walled Carbon Nano Tubes (MWCNT). They have thermal conductivity around 3000 W/mK while other materials used as nanoparticles like CuO have thermal conductivity of 76.5 W/mK. Due to this fact, MWCNT nanoparticles have potential to be used in nanofluids production, aiming to increase heat transfer rate in energy systems. In this context, the main goal of this paper is to evaluate from the synthesis to the experimental measurement of thermal conductivity of nanofluid samples based on functionalized (-OH) MWCNT nanoparticles. They will be analyzed nanoparticles with different functionalization degrees (4% wt, 6% wt, and 9% wt). In addition, it will be quantified other thermophysical properties (dynamic viscosity, specific heat and specific mass) of the synthetized nanofluids. So, the present work can contribute with experimental data that will help researches in the study and development of MWCNT nanofluids. According to the results, the maximum increment obtained in thermal conductivity was 10.65% in relation to the base fluid (water).展开更多
We present in this paper a quantum secure direct communication (QSDC) protocol by using partially entangled states. In the scheme a third party (Trent) is introduced to authenticate the participants. After authent...We present in this paper a quantum secure direct communication (QSDC) protocol by using partially entangled states. In the scheme a third party (Trent) is introduced to authenticate the participants. After authentication, Alice can directly, deterministically and successfully send a secret message to Bob. The security of the scheme is also discussed and confirmed.展开更多
Based on nonequilibrium Green's function and first-principles calculations, we investigate the change in molecular conductance caused by different adsorption sites with the presence of additional Au atom around the m...Based on nonequilibrium Green's function and first-principles calculations, we investigate the change in molecular conductance caused by different adsorption sites with the presence of additional Au atom around the metal- molecule contact in the system that benzene sandwiched between two Au(111) leads. The motivation is the variable situations that may arise in break junction experiments. Numerical results show that the enhancement of conductance induced by the presence of additional Au is dependent on the adsorption sites of anchoring atom. When molecule is located on top site with the presence of additional Au atoms, it can increase molecular conductance remarkably and present negative differential resistance under applied bias which cannot be found in bridge and hollow sites. Furthermore, the effects of different distance between additional Au and sulfur atoms in these three adsorption sites are also discussed.展开更多
Turbulence is a phenomenon which presents peculiarities when it is experimented or simulated.This occurs due to its complexity and high sensibility to the inlet conditions of the turbulent flow fields,as well as the p...Turbulence is a phenomenon which presents peculiarities when it is experimented or simulated.This occurs due to its complexity and high sensibility to the inlet conditions of the turbulent flow fields,as well as the presence of a large range of time and length scales.A simplification for this situation is obtained with the use of approximations and turbulence models.In the present work,the Largeeddy Simulations methodology was applied,aiming the modeling of the previously mentioned complexity,which consists in using a filter to resolve the large scales while the remaining scales were determined by classical and dynamic Smagorinsky models.Three different approximations for the inlet conditions were applied:white noise,Random Flow Generation(RFG)and Synthetic Eddy Method(SEM).It was possible to realize that the use of the dynamic Smagorinky model and the RFG or SEM methodologies resulted in a better characterization of the studied flow.展开更多
This study investigates the efficiency of a crude enzymatic extract produced by Aspergillus fumigatus SCBM6 by solid state fermentation(SSF)in the hydrolysis of alkali pretreated sugarcane bagasse(PTB).After SSF using...This study investigates the efficiency of a crude enzymatic extract produced by Aspergillus fumigatus SCBM6 by solid state fermentation(SSF)in the hydrolysis of alkali pretreated sugarcane bagasse(PTB).After SSF using in natura sugarcane bagasse(SCB),the enzymatic extract presented 21.33 U.g^-1 of β-glucosidase and 544.46 U.g^-1 of xylanase.The alkaline pretreatment with sodium hydroxide 2%NaOH(w/v)removed 43% of the lignin from PTB and the cellulosic fraction increased to 75%.The hydrolysis was optimized as a function of time,temperature,and concentration of PTB.After hydrolysis,the maximum yield(30.05%)of total released reducing sugars(TRS)was obtained under the following conditions:24 h,55℃,2% of PTB and 3 U.g^-1 of β-glucosidase(CBU).Furthermore,an approximate TRS value(26.4%)was also obtained after saccharification carried out during 6 h,55℃,4% of PTB and 1 CBU.These results indicate that hydrolysis can be performed in a short incubation period and with low enzymatic load for reasonable TRS release.展开更多
Rainfall expresses one of the most complex climate factors in Southeastern Brazil. Understanding the dynamics and temporal trends of rainfall represents a significant challenge due to regional and even global mechanis...Rainfall expresses one of the most complex climate factors in Southeastern Brazil. Understanding the dynamics and temporal trends of rainfall represents a significant challenge due to regional and even global mechanisms, such as FS (Frontal Systems) and the SACZ (South Atlantic Convergence Zone), and the interaction with the Atlantic and Pacific Oceans. The present study aimed at analyzing the pluviometric tendencies in S<span style="color:#4F4F4F;font-family:"font-size:14px;white-space:normal;background-color:#F7F7F7;">ã</span>o Carlos/SP, in the countryside of S<span style="color:#4F4F4F;font-family:"font-size:14px;white-space:normal;background-color:#F7F7F7;">ã</span>o Paulo State. Laplace trend test was used to comprehend the temporal evolution of daily rainfall in the region in the historical series 1979-2017, in seven pluviometric stations (climatological or surface stations). Significant fluctuations in interannual trends and between seasons were observed. However, it was noted that the beginning of the 1980s showed positive trends, whereas, as of the year 2000, most of the stations demonstrated negative trends, indicating a reduction in daily rainfall volume due to the great tropical climatic variability of Brazil. Emphasis should also be given to the regional and local effects, such as elevation and urbanization, respectively, which corroborate such differences among the analyzed stations. This methodology is of considerable value for the observation of pluviometric trends, and future studies can validate such a tool in climatological studies.展开更多
AIM: To evaluate the outcomes and complications of vitrectomy for diabetic retinopathy using preoperative bevacizumab and silicone oil(SO) tamponade. METHODS: Eighty-four eyes(64 patients) that underwent vitrectomy to...AIM: To evaluate the outcomes and complications of vitrectomy for diabetic retinopathy using preoperative bevacizumab and silicone oil(SO) tamponade. METHODS: Eighty-four eyes(64 patients) that underwent vitrectomy to treat severe proliferative diabetic retinopathy were enrolled in this retrospective, interventional, serial case study. All patients provided signed informed consent preoperatively and the off-label use of bevacizumab was discussed with the patients and confirmed in the signed consent forms. Bevacizumab injections and SO tamponades were used in all cases and intraoperative complications, postoperative complications and postoperative outcomes were analyzed. The primary outcome was the occurrence of intraop-erative and postoperative bleeding during and after vitrectomy and SO removal. The secondary outcomes were other complications that occurred during the two surgeries, the surgical time and the postoperative best-corrected visual acuity(BCVA) in log MAR scale compared with the preoperative BCVA in logM AR. The statistical analysis was performed with GraphP ad Prism 5(Graph Pad Software, La Jolla, CA) using a column analysis(column statistics and frequency distribution) for the noncomparative analysis and a paired t-test for the comparative study;P < 0.05 indicated statistical significance. RESULTS: Eighty-four eyes of 64 patients were included in the study. Of the 88 eyes initially recruited, 4 eyes(0.45%) developed phthisis bulbi and were excluded from the statistical analysis. Bevacizumab was injected between 1 and 10 d before surgery, with a mean of 3.7 ± 2.2 d. Forty-six eyes(54.8%) had no complications during the surgery;6 eyes(7.1%) had vitreous hemorrhage;21(25%) had a single retinal tear;7(8.3%) had two or more retinal tears, one of which was in the posterior pole, temporal to the fovea;2(2.4%) had retinal tears associated with hemorrhage;1(1.2%) had choroidal detachment;and 1 eye(1.2%) had dialysis in the temporal entrance of the trocar. After the surgery and SO removal, 60 eyes(71.4%) had no complications, 8(9.5%) had vitreous hemorrhage, 2(2.4%) had a macular hole, 2(2.4%) had an epiretinal membrane, 7(8.3%) had rhegmatogenous retinal detachment, 2(2.4%) had neovascular glaucoma, 2(2.4%) had a corneal trophic ulcer, and 1(1.2%) had central venous occlusion. The surgical time ranged from 40 to 120 min, with a mean of 77.8 ± 20.7 min. The final status of the lens was 34 phakic eyes(40.5%) and 24 pseudophakic eyes(28.5%);in 26 eyes(31%), the lens was extracted via phacoemulsification combined with vitrectomy or SO removal. The preoperative BCVA in logM AR ranged from 0.1 to 3.0, with a mean of 1.6 ± 0.9;the postoperative BCVA in logM AR ranged from 0.0 to 3.0, with a mean of 0.9 ± 0.7;the preoperative and postoperativeBCVA values were significantly different(P < 0.0001). CONCLUSION: Bevacizumab may diminish intraoperative and postoperative bleeding, thus possibly facilitating intraoperative maneuvers, diminishing the complications and playing a role in the final outcomes of these eyes.展开更多
Renewable hydrocarbons refer to fuels consisting of hydrocarbons of 10 to 20 carbon atoms, produced from biomass, and free of oxygen. Hydrocracking, hydrodeoxygenation and hydrotreatment processes for the production o...Renewable hydrocarbons refer to fuels consisting of hydrocarbons of 10 to 20 carbon atoms, produced from biomass, and free of oxygen. Hydrocracking, hydrodeoxygenation and hydrotreatment processes for the production of renewable hydrocarbons are described in the literature. Microalgae have been targeted in recent years to synthesize biomass that can be used in the production of biofuels, such as renewable hydrocarbons, biodiesel or ethanol second generation. In this context the lineage Monoraphidium sp. was selected from previous ecophysiological studies and its potential to produce lipids to develop this research related with the extraction of the bio-oil of the wet biomass of Monoraphidium sp. through heat treatment. Consecutively the bio-oil was used as raw material for the production of hydrocarbons through hydrocracking and hydrodeoxygenation processes (HDO) as: decarbonylation, decarboxylation, dehydratation, with in situ production of hydrogen from liquid-phase reforming of glycerol. The reactions were carried out under two different temperature conditions, 350°C and 300°C, respectively, for 1 h and using ruthenium alumina catalyst (Ru/Al2O3). The results showed the bio-oil processing route at a temperature of 350°C promising for the production of hydrocarbons achieving a conversion of 81.54%.展开更多
This study aimed to understand bark thickness variations of Araucaria angustifolia(Bertol.)Kuntze trees growing in natural forest remnants in southern Brazil,and their relationship with quantitative and qualitative at...This study aimed to understand bark thickness variations of Araucaria angustifolia(Bertol.)Kuntze trees growing in natural forest remnants in southern Brazil,and their relationship with quantitative and qualitative attributes.Bark thickness must be accurately estimated in order to determine timber volume stocks.This is an important variable for the sustainable management and conservation of araucaria forests.In spite of its importance and visibility,bark thickness variations have not been evaluated for this key species in southern Brazil.A total of 104 trees were selected,and their qualitative and quantitative attributes such as diameter at breast height(D_(BH)),height(H),crown base height(C_(BH)),crown length(C_(L)),social position(S_(P)),stoniness(S_(T)),position on the relief(P_(R)),vitality(V_T)and branch arrangement(B_(A))were measured.The trees were categorized into two groups:red bark or gray bark.Regression analysis and artificial neural networks(ANN)were used for modelling bark thickness.The results indicate that:(1)bark thickness showed good correlation to D_(BH),with 0.76 as coefficient of determination(RS_P),0.540 as Mean Absolute Error(M_(AE))and 22.4 root-meansquare error in percentage(R_(MSE%));(2)the trend changed according to bark colour,with significant differences for the intersection(_0–Pr>F:p=0.0124)and slope(β_(1)–Pr>F:p=0.0126)of bark thickness curves between groups;(3)the highest correlation of bark thickness was found with:D_(BH)(ρ=0.88),H(ρ=0.58),C_(BH)(ρ=0.46),S_(P)(ρ=-0.52),and B_(A)(ρ=-0.32);(4)modelling with ANN confirmed high adjustment(R^(2)=0.99)and accuracy(R_(MSE%)=3.0)of the estimates.ANN is an efficient and robust technique for the modelling of various qualitative and quantitative attributes commonly used in forest mensuration.The effective use of ANN to estimate araucaria bark in natural forests reinforces its potential,besides the possibility of application for other forest species.展开更多
Microalgae are unicellular organisms capable of photosynthesis, turning sunlight and carbon dioxide (CO2) into rich biomass. Precisely because of this definition, in recent years various sectors have been targeting th...Microalgae are unicellular organisms capable of photosynthesis, turning sunlight and carbon dioxide (CO2) into rich biomass. Precisely because of this definition, in recent years various sectors have been targeting their ability to reduce CO2 emissions and the capacity of simultaneously synthesize biomass which can be later used to produce bio-fuels. Besides being considered fast-growth microorganisms, microalgae have a diverse biochemical composition with similar characteristics to traditional biomass. In this context, the present work aimed to evaluate the biofixation of CO2 by the microalgae Monoraphidium sp., cultivated in a closed-window type photobioreactor, as well as characterization of microalgal biomass produced in relation to the total lipid content (TL), lipids converted into biodiesel (LCB), carbohydrates and proteins. The results achieved showed that the best result was obtained after 24 h of cultivation, where for each gram of biomass produced approximately 1.2 g of CO2 were consumed. In the growth phase the average biomass productivity in the Janela photobioreactor was 58 mg·L-1·day-1 concluding that microalgae culture systems could be coupled to the chimneys of large industries emitters CO2 using this gas, resulting from combustion processes, in the process of photosynthesis. The biomass Monoraphidium sp. produced had a content of lipids converted into biodiesel of approximately 8.36% ± 2.69%, carbohydrates 32% ± 3.37% and proteins 34.26% ± 0.41%.展开更多
The objective of this work was to study the effect of the heat treatment and further operation aging on the stereological parameters(size,quantity and volume fraction)of precipitates within ferrite grains of a creep-r...The objective of this work was to study the effect of the heat treatment and further operation aging on the stereological parameters(size,quantity and volume fraction)of precipitates within ferrite grains of a creep-resistant 1.25Cr0.5Mo steel after long-term operation.The heat treatment was similar to the treatment that is carried out in industrial steam pipelines after welding(post weld heat treatment-PWHT)during installation and/or repairing.The operation aging corresponds to a subsequent long in-service operation after repairing.To determine the stereological parameters,SEM digital images were taken from samples of this material after conditions of in-service-aged(after long-term operation),in-service-aged and heat-treated(simulating repairing)and in-service-aged,heat-treated and in-laboratory aged(simulating subsequent long-term operation after repairing).The results indicate that the changes in the stereological parameters of the precipitates within ferrite grains after PWHT is associated with the coarsening process of the within-ferrite-grain precipitates as well as stabilizing the microstructure,since the material aging after PWHT of an in-serviced aged material would not change the stereological parameters.展开更多
Anatomical studies in the leaflet globoid galls of Caryocar brasiliense, the “pequi”, aimed to answer how oviposition and the feeding behavior of the galling herbivores altered the morphogenical patterns of the host...Anatomical studies in the leaflet globoid galls of Caryocar brasiliense, the “pequi”, aimed to answer how oviposition and the feeding behavior of the galling herbivores altered the morphogenical patterns of the host plant. C. brasiliense globoid gall was 1.28 ± 0.20 mm × 0.90 ± 0.25 mm, with hairy surface;it is sessile and projected to the abaxial surface. Young galls were red while the mature ones were green. Preferentially, they were formed next to leaf margin and possessed one larval chamber containing a single galling specimen. Gall epidermis was uniseriate, with thicker cuticle and more hairy. In some spots, epidermis was substituted by periderm, which indicated the expression of a character usually absent in the leaf laminas. Morphological and anatomical features of these gall morphotype, such as its position in leaf lamina, the fact of being truly closed galls, with typical nutritive tissue involved by sclerenchyma, made them next to the pattern proposed for galls induced by some Hymenoptera.展开更多
Background Probiotic supplementation has been used to alleviate abdominal pain in children and adolescents with irritable bowel syndrome(IBS),but the evidence is not compelling.Thus,a systematic review and meta-analys...Background Probiotic supplementation has been used to alleviate abdominal pain in children and adolescents with irritable bowel syndrome(IBS),but the evidence is not compelling.Thus,a systematic review and meta-analysis of randomized clinical trials(RCTs)were performed to investigate the effects of probiotic supplementation on abdominal pain in pediatric patients with IBS.Methods PubMed/MEDLINE,Web of Science,Scopus,Cochrane Library,and Embase were the available databases searched to find relevant randomized clinical trials up to April 2021.The effect size was expressed as weighted mean differenee(WMD)and 95% confidence interval(CI).Results Seven RCTs with 441 participants were included,from which the meta-analysis demonstrated that probiotic supplementation has a significant effect on reducing abdominal pain in pediatric patients with IBS(WMD=-2.36:95%CI-4.12 to-0.60;P=0.009).Although our study involved children and adolescents(≤18 years),the effects of probiotic supplementation seem to be more potent in patients under 10 years old(WMD=-2.55;95%CI-2.84 to -2.27)compared to patients aged 10-18 years(WMD=-1.70;95%CI-2.18 to -1.22).The length of supplementation longer than four weeks was more effective(WMD=-2.43;95%CI-2.76 to -2.09).Conclusion Probiotic supplementation can reduce abdominal pain in pediatric patients with IBS.展开更多
Termite colonies are usully headed by primary reproductives,which estab-listh nests during the swar ming scason.However,secondary reproductives may develop in some specics and become supplementary or replacement breed...Termite colonies are usully headed by primary reproductives,which estab-listh nests during the swar ming scason.However,secondary reproductives may develop in some specics and become supplementary or replacement breeders,extending colony lifes-pan.Here we investigate the developmental origin,fecundity and genetic characterizaion of ergatoid reproductives in the Neotropical termite Nasuitermes aquilinus(Holmgren),using morphometrical and histological techniques,five micosiallitle loci and the COI mitochondrial DNA.Twelve measurements performed on 208 apterous individuals of Nuauidius revealed 10 groups,including ergatoid females,which developed from major workers through two successive molts.and were characterized by the presence of imaginal features such as eyes andl wing buds.The difentiation of these features was correlated to physogastric development in these ergatoids,Histology revealed ooeytes in all matu-ration sages in worker-derived reproductives of N aquidinus,presence of nonflagellate spermatozoa inside the spermatheea,and royal fa body.Thus,ergatoid reproduwetives were reproductively functional.According to the genotypes of 221 individuals from 11 nests,and mitochondrial haplotypes of 43 ergatoids,73%of the colomies were simple families,whereas 27%were extendbed families.Despite the oecurenee of related reproductives,low inbreeding rates were detected within and among colonies.Such values could be explained given that sib mating itself cannot result in a higher inbreeding rate but depend on several factors discussed in detail.This is the first study to investigate the genetic structure of termite colonies influenced by the development of ergatoids and further investigations are encouraged 10 understand the inflwence of these reproductives on colony lifespan.展开更多
基金supported by the Coordenacao de Aperfeicoamento de Pessoal de Nível Superior–Brasil (CAPES)–Finance Code 001the Postgraduate Programme in Forest Engineering of the Federal University of Lavras (PPGEF/UFLA)and Group of Optimization and Planning (GOPLAN/UFLA/LEMAF-Forest Management Research Lab)。
文摘Selective logging is well-recognized as an effective practice in sustainable forest management.However,the ecological efficiency or resilience of the residual stand is often in doubt.Recovery time depends on operational variables,diversity,and forest structure.Selective logging is excellent but is open to changes.This may be resolved by mathematical programming and this study integrates the economic-ecological aspects in multi-objective function by applying two evolutionary algorithms.The function maximizes remaining stand diversity,merchantable logs,and the inverse of distance between trees for harvesting and log landings points.The Brazilian rainforest database(566 trees)was used to simulate our 216-ha model.The log landing design has a maximum volume limit of 500 m3.The nondominated sorting genetic algorithm was applied to solve the main optimization problem.In parallel,a sub-problem(p-facility allocation)was solved for landing allocation by a genetic algorithm.Pareto frontier analysis was applied to distinguish the gradientsα-economic,β-ecological,andγ-equilibrium.As expected,the solutions have high diameter changes in the residual stand(average removal of approximately 16 m^(3) ha^(-1)).All solutions showed a grouping of trees selected for harvesting,although there was no formation of large clearings(percentage of canopy removal<7%,with an average of 2.5 ind ha^(-1)).There were no differences in floristic composition by preferentially selecting species with greater frequency in the initial stand for harvesting.This implies a lower impact on the demographic rates of the remaining stand.The methodology should support projects of reduced impact logging by using spatial-diversity information to guide better practices in tropical forests.
文摘A possible way to increase thermal conductivity of working fluids, while keeping pressure drop at acceptable levels, is through nanofluids. Nanofluids are nano-sized particles dispersed in conventional working fluids. A great number of materials have potential to be used in nanoparticles production and then in nanofluids;one of them is Multi-Walled Carbon Nano Tubes (MWCNT). They have thermal conductivity around 3000 W/mK while other materials used as nanoparticles like CuO have thermal conductivity of 76.5 W/mK. Due to this fact, MWCNT nanoparticles have potential to be used in nanofluids production, aiming to increase heat transfer rate in energy systems. In this context, the main goal of this paper is to evaluate from the synthesis to the experimental measurement of thermal conductivity of nanofluid samples based on functionalized (-OH) MWCNT nanoparticles. They will be analyzed nanoparticles with different functionalization degrees (4% wt, 6% wt, and 9% wt). In addition, it will be quantified other thermophysical properties (dynamic viscosity, specific heat and specific mass) of the synthetized nanofluids. So, the present work can contribute with experimental data that will help researches in the study and development of MWCNT nanofluids. According to the results, the maximum increment obtained in thermal conductivity was 10.65% in relation to the base fluid (water).
基金Project supported by National Natural Science Foundation of China (Grant No 10534030).
文摘We present in this paper a quantum secure direct communication (QSDC) protocol by using partially entangled states. In the scheme a third party (Trent) is introduced to authenticate the participants. After authentication, Alice can directly, deterministically and successfully send a secret message to Bob. The security of the scheme is also discussed and confirmed.
基金Supported by the Natural Science Foundation of Shandong Province and the National Natural Science Foundations of China under Grant Nos.10574082 and Z2005A01.
文摘Based on nonequilibrium Green's function and first-principles calculations, we investigate the change in molecular conductance caused by different adsorption sites with the presence of additional Au atom around the metal- molecule contact in the system that benzene sandwiched between two Au(111) leads. The motivation is the variable situations that may arise in break junction experiments. Numerical results show that the enhancement of conductance induced by the presence of additional Au is dependent on the adsorption sites of anchoring atom. When molecule is located on top site with the presence of additional Au atoms, it can increase molecular conductance remarkably and present negative differential resistance under applied bias which cannot be found in bridge and hollow sites. Furthermore, the effects of different distance between additional Au and sulfur atoms in these three adsorption sites are also discussed.
文摘Turbulence is a phenomenon which presents peculiarities when it is experimented or simulated.This occurs due to its complexity and high sensibility to the inlet conditions of the turbulent flow fields,as well as the presence of a large range of time and length scales.A simplification for this situation is obtained with the use of approximations and turbulence models.In the present work,the Largeeddy Simulations methodology was applied,aiming the modeling of the previously mentioned complexity,which consists in using a filter to resolve the large scales while the remaining scales were determined by classical and dynamic Smagorinsky models.Three different approximations for the inlet conditions were applied:white noise,Random Flow Generation(RFG)and Synthetic Eddy Method(SEM).It was possible to realize that the use of the dynamic Smagorinky model and the RFG or SEM methodologies resulted in a better characterization of the studied flow.
文摘This study investigates the efficiency of a crude enzymatic extract produced by Aspergillus fumigatus SCBM6 by solid state fermentation(SSF)in the hydrolysis of alkali pretreated sugarcane bagasse(PTB).After SSF using in natura sugarcane bagasse(SCB),the enzymatic extract presented 21.33 U.g^-1 of β-glucosidase and 544.46 U.g^-1 of xylanase.The alkaline pretreatment with sodium hydroxide 2%NaOH(w/v)removed 43% of the lignin from PTB and the cellulosic fraction increased to 75%.The hydrolysis was optimized as a function of time,temperature,and concentration of PTB.After hydrolysis,the maximum yield(30.05%)of total released reducing sugars(TRS)was obtained under the following conditions:24 h,55℃,2% of PTB and 3 U.g^-1 of β-glucosidase(CBU).Furthermore,an approximate TRS value(26.4%)was also obtained after saccharification carried out during 6 h,55℃,4% of PTB and 1 CBU.These results indicate that hydrolysis can be performed in a short incubation period and with low enzymatic load for reasonable TRS release.
文摘Rainfall expresses one of the most complex climate factors in Southeastern Brazil. Understanding the dynamics and temporal trends of rainfall represents a significant challenge due to regional and even global mechanisms, such as FS (Frontal Systems) and the SACZ (South Atlantic Convergence Zone), and the interaction with the Atlantic and Pacific Oceans. The present study aimed at analyzing the pluviometric tendencies in S<span style="color:#4F4F4F;font-family:"font-size:14px;white-space:normal;background-color:#F7F7F7;">ã</span>o Carlos/SP, in the countryside of S<span style="color:#4F4F4F;font-family:"font-size:14px;white-space:normal;background-color:#F7F7F7;">ã</span>o Paulo State. Laplace trend test was used to comprehend the temporal evolution of daily rainfall in the region in the historical series 1979-2017, in seven pluviometric stations (climatological or surface stations). Significant fluctuations in interannual trends and between seasons were observed. However, it was noted that the beginning of the 1980s showed positive trends, whereas, as of the year 2000, most of the stations demonstrated negative trends, indicating a reduction in daily rainfall volume due to the great tropical climatic variability of Brazil. Emphasis should also be given to the regional and local effects, such as elevation and urbanization, respectively, which corroborate such differences among the analyzed stations. This methodology is of considerable value for the observation of pluviometric trends, and future studies can validate such a tool in climatological studies.
文摘AIM: To evaluate the outcomes and complications of vitrectomy for diabetic retinopathy using preoperative bevacizumab and silicone oil(SO) tamponade. METHODS: Eighty-four eyes(64 patients) that underwent vitrectomy to treat severe proliferative diabetic retinopathy were enrolled in this retrospective, interventional, serial case study. All patients provided signed informed consent preoperatively and the off-label use of bevacizumab was discussed with the patients and confirmed in the signed consent forms. Bevacizumab injections and SO tamponades were used in all cases and intraoperative complications, postoperative complications and postoperative outcomes were analyzed. The primary outcome was the occurrence of intraop-erative and postoperative bleeding during and after vitrectomy and SO removal. The secondary outcomes were other complications that occurred during the two surgeries, the surgical time and the postoperative best-corrected visual acuity(BCVA) in log MAR scale compared with the preoperative BCVA in logM AR. The statistical analysis was performed with GraphP ad Prism 5(Graph Pad Software, La Jolla, CA) using a column analysis(column statistics and frequency distribution) for the noncomparative analysis and a paired t-test for the comparative study;P < 0.05 indicated statistical significance. RESULTS: Eighty-four eyes of 64 patients were included in the study. Of the 88 eyes initially recruited, 4 eyes(0.45%) developed phthisis bulbi and were excluded from the statistical analysis. Bevacizumab was injected between 1 and 10 d before surgery, with a mean of 3.7 ± 2.2 d. Forty-six eyes(54.8%) had no complications during the surgery;6 eyes(7.1%) had vitreous hemorrhage;21(25%) had a single retinal tear;7(8.3%) had two or more retinal tears, one of which was in the posterior pole, temporal to the fovea;2(2.4%) had retinal tears associated with hemorrhage;1(1.2%) had choroidal detachment;and 1 eye(1.2%) had dialysis in the temporal entrance of the trocar. After the surgery and SO removal, 60 eyes(71.4%) had no complications, 8(9.5%) had vitreous hemorrhage, 2(2.4%) had a macular hole, 2(2.4%) had an epiretinal membrane, 7(8.3%) had rhegmatogenous retinal detachment, 2(2.4%) had neovascular glaucoma, 2(2.4%) had a corneal trophic ulcer, and 1(1.2%) had central venous occlusion. The surgical time ranged from 40 to 120 min, with a mean of 77.8 ± 20.7 min. The final status of the lens was 34 phakic eyes(40.5%) and 24 pseudophakic eyes(28.5%);in 26 eyes(31%), the lens was extracted via phacoemulsification combined with vitrectomy or SO removal. The preoperative BCVA in logM AR ranged from 0.1 to 3.0, with a mean of 1.6 ± 0.9;the postoperative BCVA in logM AR ranged from 0.0 to 3.0, with a mean of 0.9 ± 0.7;the preoperative and postoperativeBCVA values were significantly different(P < 0.0001). CONCLUSION: Bevacizumab may diminish intraoperative and postoperative bleeding, thus possibly facilitating intraoperative maneuvers, diminishing the complications and playing a role in the final outcomes of these eyes.
文摘Renewable hydrocarbons refer to fuels consisting of hydrocarbons of 10 to 20 carbon atoms, produced from biomass, and free of oxygen. Hydrocracking, hydrodeoxygenation and hydrotreatment processes for the production of renewable hydrocarbons are described in the literature. Microalgae have been targeted in recent years to synthesize biomass that can be used in the production of biofuels, such as renewable hydrocarbons, biodiesel or ethanol second generation. In this context the lineage Monoraphidium sp. was selected from previous ecophysiological studies and its potential to produce lipids to develop this research related with the extraction of the bio-oil of the wet biomass of Monoraphidium sp. through heat treatment. Consecutively the bio-oil was used as raw material for the production of hydrocarbons through hydrocracking and hydrodeoxygenation processes (HDO) as: decarbonylation, decarboxylation, dehydratation, with in situ production of hydrogen from liquid-phase reforming of glycerol. The reactions were carried out under two different temperature conditions, 350°C and 300°C, respectively, for 1 h and using ruthenium alumina catalyst (Ru/Al2O3). The results showed the bio-oil processing route at a temperature of 350°C promising for the production of hydrocarbons achieving a conversion of 81.54%.
基金This study is supported by the Graduate Program in Forest Engineering of the Santa Catarina State University(UDESC)the Santa Catarina Research Foundation(FAPESC+3 种基金2017TR1762,2017TR639,2019TR816)the Brazilian National Council for Scientifi c and Technological Development(CNPq313887/2018-7)the Coordination for the Improvement of Higher Education Personnel(CAPES).
文摘This study aimed to understand bark thickness variations of Araucaria angustifolia(Bertol.)Kuntze trees growing in natural forest remnants in southern Brazil,and their relationship with quantitative and qualitative attributes.Bark thickness must be accurately estimated in order to determine timber volume stocks.This is an important variable for the sustainable management and conservation of araucaria forests.In spite of its importance and visibility,bark thickness variations have not been evaluated for this key species in southern Brazil.A total of 104 trees were selected,and their qualitative and quantitative attributes such as diameter at breast height(D_(BH)),height(H),crown base height(C_(BH)),crown length(C_(L)),social position(S_(P)),stoniness(S_(T)),position on the relief(P_(R)),vitality(V_T)and branch arrangement(B_(A))were measured.The trees were categorized into two groups:red bark or gray bark.Regression analysis and artificial neural networks(ANN)were used for modelling bark thickness.The results indicate that:(1)bark thickness showed good correlation to D_(BH),with 0.76 as coefficient of determination(RS_P),0.540 as Mean Absolute Error(M_(AE))and 22.4 root-meansquare error in percentage(R_(MSE%));(2)the trend changed according to bark colour,with significant differences for the intersection(_0–Pr>F:p=0.0124)and slope(β_(1)–Pr>F:p=0.0126)of bark thickness curves between groups;(3)the highest correlation of bark thickness was found with:D_(BH)(ρ=0.88),H(ρ=0.58),C_(BH)(ρ=0.46),S_(P)(ρ=-0.52),and B_(A)(ρ=-0.32);(4)modelling with ANN confirmed high adjustment(R^(2)=0.99)and accuracy(R_(MSE%)=3.0)of the estimates.ANN is an efficient and robust technique for the modelling of various qualitative and quantitative attributes commonly used in forest mensuration.The effective use of ANN to estimate araucaria bark in natural forests reinforces its potential,besides the possibility of application for other forest species.
基金We thank the National Council for Scientific and Technological Development(CNPq)for the financial support and the GREENTEC Laboratory(UFRJ)for their support in the research.
文摘Microalgae are unicellular organisms capable of photosynthesis, turning sunlight and carbon dioxide (CO2) into rich biomass. Precisely because of this definition, in recent years various sectors have been targeting their ability to reduce CO2 emissions and the capacity of simultaneously synthesize biomass which can be later used to produce bio-fuels. Besides being considered fast-growth microorganisms, microalgae have a diverse biochemical composition with similar characteristics to traditional biomass. In this context, the present work aimed to evaluate the biofixation of CO2 by the microalgae Monoraphidium sp., cultivated in a closed-window type photobioreactor, as well as characterization of microalgal biomass produced in relation to the total lipid content (TL), lipids converted into biodiesel (LCB), carbohydrates and proteins. The results achieved showed that the best result was obtained after 24 h of cultivation, where for each gram of biomass produced approximately 1.2 g of CO2 were consumed. In the growth phase the average biomass productivity in the Janela photobioreactor was 58 mg·L-1·day-1 concluding that microalgae culture systems could be coupled to the chimneys of large industries emitters CO2 using this gas, resulting from combustion processes, in the process of photosynthesis. The biomass Monoraphidium sp. produced had a content of lipids converted into biodiesel of approximately 8.36% ± 2.69%, carbohydrates 32% ± 3.37% and proteins 34.26% ± 0.41%.
基金supported by the bilateral agreement CAPES-Brazil/MES–Cuba(project number 146/12)carried out at the Brazilian research laboratories LAPROSOLDA-LDTAD from Federal University of Uberlandia(UFU)DEMa-CCDM from Federal University of Sao Carlos(UFSCar)。
文摘The objective of this work was to study the effect of the heat treatment and further operation aging on the stereological parameters(size,quantity and volume fraction)of precipitates within ferrite grains of a creep-resistant 1.25Cr0.5Mo steel after long-term operation.The heat treatment was similar to the treatment that is carried out in industrial steam pipelines after welding(post weld heat treatment-PWHT)during installation and/or repairing.The operation aging corresponds to a subsequent long in-service operation after repairing.To determine the stereological parameters,SEM digital images were taken from samples of this material after conditions of in-service-aged(after long-term operation),in-service-aged and heat-treated(simulating repairing)and in-service-aged,heat-treated and in-laboratory aged(simulating subsequent long-term operation after repairing).The results indicate that the changes in the stereological parameters of the precipitates within ferrite grains after PWHT is associated with the coarsening process of the within-ferrite-grain precipitates as well as stabilizing the microstructure,since the material aging after PWHT of an in-serviced aged material would not change the stereological parameters.
基金thank CNPq,CAPES and FAPEMIG for the scholarships,and financial support for the development of this research.
文摘Anatomical studies in the leaflet globoid galls of Caryocar brasiliense, the “pequi”, aimed to answer how oviposition and the feeding behavior of the galling herbivores altered the morphogenical patterns of the host plant. C. brasiliense globoid gall was 1.28 ± 0.20 mm × 0.90 ± 0.25 mm, with hairy surface;it is sessile and projected to the abaxial surface. Young galls were red while the mature ones were green. Preferentially, they were formed next to leaf margin and possessed one larval chamber containing a single galling specimen. Gall epidermis was uniseriate, with thicker cuticle and more hairy. In some spots, epidermis was substituted by periderm, which indicated the expression of a character usually absent in the leaf laminas. Morphological and anatomical features of these gall morphotype, such as its position in leaf lamina, the fact of being truly closed galls, with typical nutritive tissue involved by sclerenchyma, made them next to the pattern proposed for galls induced by some Hymenoptera.
文摘Background Probiotic supplementation has been used to alleviate abdominal pain in children and adolescents with irritable bowel syndrome(IBS),but the evidence is not compelling.Thus,a systematic review and meta-analysis of randomized clinical trials(RCTs)were performed to investigate the effects of probiotic supplementation on abdominal pain in pediatric patients with IBS.Methods PubMed/MEDLINE,Web of Science,Scopus,Cochrane Library,and Embase were the available databases searched to find relevant randomized clinical trials up to April 2021.The effect size was expressed as weighted mean differenee(WMD)and 95% confidence interval(CI).Results Seven RCTs with 441 participants were included,from which the meta-analysis demonstrated that probiotic supplementation has a significant effect on reducing abdominal pain in pediatric patients with IBS(WMD=-2.36:95%CI-4.12 to-0.60;P=0.009).Although our study involved children and adolescents(≤18 years),the effects of probiotic supplementation seem to be more potent in patients under 10 years old(WMD=-2.55;95%CI-2.84 to -2.27)compared to patients aged 10-18 years(WMD=-1.70;95%CI-2.18 to -1.22).The length of supplementation longer than four weeks was more effective(WMD=-2.43;95%CI-2.76 to -2.09).Conclusion Probiotic supplementation can reduce abdominal pain in pediatric patients with IBS.
基金grants from Fundacao de Amparo a Pesquisa do Estado de Sao Paulo-FAPESP(Proc.2012/23898-0.2014/25857-4 and 2017/04525-1)Conselho Nacional de Desenvolvi-mento Tecnologico-CNPq(Proc.305539/2014-0)Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior-CAPES(Financial code 001).
文摘Termite colonies are usully headed by primary reproductives,which estab-listh nests during the swar ming scason.However,secondary reproductives may develop in some specics and become supplementary or replacement breeders,extending colony lifes-pan.Here we investigate the developmental origin,fecundity and genetic characterizaion of ergatoid reproductives in the Neotropical termite Nasuitermes aquilinus(Holmgren),using morphometrical and histological techniques,five micosiallitle loci and the COI mitochondrial DNA.Twelve measurements performed on 208 apterous individuals of Nuauidius revealed 10 groups,including ergatoid females,which developed from major workers through two successive molts.and were characterized by the presence of imaginal features such as eyes andl wing buds.The difentiation of these features was correlated to physogastric development in these ergatoids,Histology revealed ooeytes in all matu-ration sages in worker-derived reproductives of N aquidinus,presence of nonflagellate spermatozoa inside the spermatheea,and royal fa body.Thus,ergatoid reproduwetives were reproductively functional.According to the genotypes of 221 individuals from 11 nests,and mitochondrial haplotypes of 43 ergatoids,73%of the colomies were simple families,whereas 27%were extendbed families.Despite the oecurenee of related reproductives,low inbreeding rates were detected within and among colonies.Such values could be explained given that sib mating itself cannot result in a higher inbreeding rate but depend on several factors discussed in detail.This is the first study to investigate the genetic structure of termite colonies influenced by the development of ergatoids and further investigations are encouraged 10 understand the inflwence of these reproductives on colony lifespan.