To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Wild poinsettia (Euphorbia heterophylla L.) is a troublesome broadleaf weed in grain production areas in South America. Herbicide resistance to multiple sites of action has been documented in this species, including protoporphyrinogen oxidase (PPO) inhibitors. We investigated the physiological and molecular bases for PPO-inhibitor resistance in a E. heterophylla population (RPPO) from Southern Brazil. Whole-plant dose–response experiments revealed a cross-resistance profile to three different chemical groups of PPO inhibitors. Based on dose–response parameters, RPPO was resistant to lactofen (47.7-fold), saflufenacil (8.6-fold), and pyraflufen-ethyl (3.5-fold). Twenty-four hours after lactofen treatment (120 g ha−1) POST, RPPO accumulated 27 times less protoporphyrin than the susceptible population (SPPO). In addition, RPPO generated 5 and 4.5 times less hydrogen peroxide and superoxide than SPPO, respectively. The chloroplast PPO (PPO1) sequences were identical between the two populations, whereas 35 single-nucleotide polymorphisms were found for the mitochondrial PPO (PPO2). Based on protein homology modeling, the Arg-128-Leu (homologous to Arg-98-Leu in common ragweed [Ambrosia artemisiifolia L.] was the only one located near the catalytic site, also in a conserved region of PPO2. The cytochrome P450 monooxygenase inhibitor malathion did not reverse resistance to lactofen in RPPO, and both populations showed similar levels of PPO1 and PPO2 expression, suggesting that metabolic resistance and PPO overexpression are unlikely. This is the first report of an Arg-128-Leu mutation in PPO2 conferring cross-resistance to PPO inhibitors in E. heterophylla.
Recently, an experimental study developed an efficient way to obtain sulfur-doped γ-graphdiyne. This study has shown that this new material could have promising applications in lithium-ion batteries, but the complete understanding of how the sulfur atoms are incorporated into the graphdiyne network is still missing. In this work, we have investigated the sulfur doping process through molecular dynamics and density functional theory simulations. Our results suggest that the doped induced distortions of the γ-graphdiyne pores prevent the incorporation of more than two sulfur atoms. The most common configuration is the incorporation of just one sulfur atom per the graphdiyne pore.
To describe the consumption of ultra-processed foods according to demographic and socioeconomic characteristics in three birth cohorts.
Data from the 2004, 1993 and 1982 Pelotas Birth Cohorts were used at 11, 22 and 30 years, respectively, collected between 2012 and 2015. Outcome was the relative contribution of ultra-processed foods from the total daily energy intake. Maternal-independent variables were self-reported skin colour, schooling, age and family income (obtained in the perinatal study), and variables of the cohort member, sex, skin colour, schooling and current family income (the last two obtained at the 11-, 22- and 30-year follow-ups of the respective cohorts). We calculated crude and adjusted means of the outcome for the whole cohorts and according to the independent variables.
11-, 22- and 30-year-old individuals.
Daily energetic contribution from ultra-processed foods was higher in the younger cohort (33·7, 29·8 and 25·1 % at 11, 22 and 30 years, respectively). Maternal schooling and family income at birth showed an inverse dose–response relationship at 11 and 22 years, but a positive dose–response at 30 years. Female sex, lower schooling and family income at 22 years and higher schooling at 30 years were associated to a higher contribution from ultra-processed foods in the daily energy intake.
Information from food and nutrition policies needs a higher dissemination, mostly among women and population groups of lower income and schooling, including its promotion in media and health services, aiming for a decreased consumption of ultra-processed foods.
The whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is one of the most important agricultural pests and virus vectors worldwide. Bemisia tabaci is considered a complex of cryptic species with at least 44 species. Among them, the species Middle East-Asia Minor 1 (MEAM1, formerly B biotype) and Mediterranean (MED, formerly Q biotype) are the most important, and they have attained global status. In Brazil, MEAM1 was first reported in the 1990s and is currently the predominant species in the country, meanwhile, MED was recently reported in the South and Southeast regions and was found to be mainly associated with ornamental plants. Currently, an increasing problem in the management of whitefly infestations in greenhouses associated with bell pepper was observed in São Paulo State, Brazil. The whiteflies were collected and identified based on a microsatellite locus (primer pair BEM23F and BEM23R) and the mitochondrial cytochrome oxidase I gene followed by restriction fragment length polymorphism analysis and sequencing. We observed that MED was the predominant species collected on bell pepper, but it was also found on tomato, cucumber, eggplant, and weeds grown in greenhouses. In open field, we found MED on tomatoes, bell peppers, and eggplants. In addition, MED was identified in Goiás State in association with ornamental plants. The begomovirus Tomato severe rugose virus and the crinivirus Tomato chlorosis virus was detected on bell pepper and tomato, respectively. Only MED specimens were found associated with the virus-infected plants. Moreover, we also investigated the endosymbionts present in the MED whiteflies. The collected populations of B. tabaci MED harbored a diversity of secondary endosymbionts, with Hamiltonella (H) found predominantly in 89 specimens of the 129 tested. These results represent a new concern for Brazilian agriculture, especially for the management of the newly introduced whitefly MED species, which must be implemented to limit the spreading and establishment of this pest in different crops in this country.
In this work, we have investigated the structural and mechanical properties of a new class of soft and superelastic materials, called schwarzynes. These materials are obtained by inserting sp carbon atoms (acetylenic groups) into the schwarzite framework. Using fully atomistic molecular dynamics simulations with the AIREBO force field, our results show that schwarzynes are stable materials up to high temperatures (1000K). Schwarzynes exhibit a very wide elastic regime, some of them up to 70% strain without structural fractures. Our preliminary results show that the elastic properties can be easily engineered by tuning the number of acetylenic groups and the crystallographic directions where they are inserted.
In the present study we employ electronic structure calculations (based on Density Functional Theory -DFT approach) and Fully Atomistic Reactive Molecular Dynamics (FARMD) simulations (based on ReaxFF reactive force field) to evaluate the reactivity of branched polyfuran (PF) derivatives and identify promising systems for chemical sensing. Condensed-to-atoms Fukui indexes (CAFI) were employed to identify the most reactive sites on the oligomers structure. The chemical sensing abilities of the most promising systems were evaluated via FARMD simulations in the presence of distinct gaseous compounds. The results indicate the derivatives PF-CCH and PF-NO₂ (i.e. CCH and NO2 as side groups) as the most promising systems for chemical sensor applications, presenting higher reactivity on the most accessible sites. An interesting correspondence between DFT and MD results was also identified, suggesting the plausibility of using CAFI parameters for the identification of improved materials for chemical sensors.
Quantifying the abundance of species is essential for their management and conservation. Much effort has been invested in surveys of freshwater dolphins in the Amazon basin but river dimensions and complex logistics limit replication of such studies across the region. We evaluated the effectiveness of using unmanned aerial vehicles (UAVs) for surveying two Amazon dolphin species, the tucuxi Sotalia fluviatilis and pink river dolphin Inia geoffrensis, in tropical rivers. In 2016 we conducted drone and visual surveys over 80 km of the Juruá River in Brazil. The aerial surveys provided higher accuracy than human observers in counting individuals detected in groups. Compared to estimates derived from visual surveys, the use of UAVs could provide a more feasible, economical and accurate estimate of Amazon river dolphin populations. The method could potentially be replicated in other important areas for the conservation of these species, to generate an improved index of river dolphin populations in the Amazon.
Over recent decades, biomass gains in remaining old-growth Amazonia forests have declined due to environmental change. Amazonia’s huge size and complexity makes understanding these changes, drivers, and consequences very challenging. Here, using a network of permanent monitoring plots at the Amazon–Cerrado transition, we quantify recent biomass carbon changes and explore their environmental drivers. Our study area covers 30 plots of upland and riparian forests sampled at least twice between 1996 and 2016 and subject to various levels of fire and drought. Using these plots, we aimed to: (1) estimate the long-term biomass change rate; (2) determine the extent to which forest changes are influenced by forest type; and (3) assess the threat to forests from ongoing environmental change. Overall, there was no net change in biomass, but there was clear variation among different forest types. Burning occurred at least once in 8 of the 12 riparian forests, while only 1 of the 18 upland forests burned, resulting in losses of carbon in burned riparian forests. Net biomass gains prevailed among other riparian and upland forests throughout Amazonia. Our results reveal an unanticipated vulnerability of riparian forests to fire, likely aggravated by drought, and threatening ecosystem conservation at the Amazon southern margins.
The natural grasslands in South America have soils with low phosphorus (P) availability (1.0 to 7.5 mg kg−1), possibly altering the absorption and accumulation of P in grasses. We evaluated the chemical fractionation of P in the leaves of the most important grasses present in these grasslands to better understand the mechanisms involved in the storage of P. The grasses studied were Axonopus affinis and Paspalum notatum (fast tissue cycling and high nutrient demand) and Andropogon lateralis and Aristida laevis (slow tissue cycling and low nutrient demand). They were grown in pots filled with an Ultisol with two levels of P: control, and addition of 50 mg P kg–1. The main P fractions were the inorganic soluble (44%) and P in RNA (26%). Addition of P increased the total P concentration, following the order A. affinis (140%) > P. notatum (116%) > A. lateralis (81%) > A. laevis (21%). In conclusion, the species A. affinis and P. notatum responded to P fertilization with high variation and accumulating P in less-structural chemical forms, such as inorganic P. The species A. lateralis and A. laevis showed low variation in the concentration of P forms, with higher P concentrations in structural forms.
Graded exercises tests are performed in adult populations; nonetheless, the use of this type of assessment is greatly understudied in overweight and obese adolescents.
To investigate heart rate autonomic responses to submaximal aerobic exercise in obese and overweight adolescents.
We recruited 40 adolescents divided into two groups: (1) overweight group comprising 10 boys and 10 girls between Z-score +1 and +2 and (2) obese group comprising 10 boys and 10 girls above Z-score >+2. Heart rate variability was analysed before (T1) and after exercise (T2–T4) on treadmill at a slope of 0%, with 70% of the maximal estimated heart rate (220 – age) for 20 minutes.
Heart rate in the overweight group was: 93.2±10.52 bpm versus 120.8±13.49 bpm versus 94.6±11.65 bpm versus 93.0±9.23 bpm, and in the obese group was: 92.0±15.41 bpm versus 117.6±16.31 bpm versus 92.1±12.9 bpm versus 91.8±14.33 bpm. High frequency in the overweight group was: 640±633.1 ms2 versus 84±174.66 ms2 versus 603.5±655.31 ms2 versus 762.6±807.21 ms2, and in the obese group was: 628.4±779.81 ms2 versus 65.4±119.34 ms2 versus 506.2±482.70 ms2 versus 677.9±939.05 ms2; and root mean square of successive differences in the overweight group was: 37.9±18.81 ms versus 10.9±8.41 ms versus 32.8±24.07 ms versus 36.7±21.86 ms, and in the obese group was: 38.7±23.17 ms versus 11.5±8.62 ms versus 32.3±16.74 ms versus 37.3±24.21 ms. These values significantly changed during exercise compared with resting values in overweight and obese groups. Moreover, we also reported no significant difference of resting parasympathetic control of heart rate between obese and overweight adolescents.
There was no significant difference of autonomic responses elicited by submaximal aerobic exercise between overweight and obese adolescents.
This study aimed to calculate economic values (EVs) and economic selection indices for milk production systems in small rural properties. The traits 305-d milk yield in kg (MY), fat (FP) and protein (PP) percentage, daily fat (FY) and protein (PY) yield, cow live weight in kg (LW), calving interval (CI), and logarithm of daily somatic cell count (SCC) in milk were considered the goals and selection criteria. The production systems were identified from 29 commercial properties based on the inventory of revenues and costs and of zootechnical field data. Later, bioeconomic models were developed to calculate the productive performance, revenues, and costs concerning milk production to estimate EVs, which were calculated as the difference in annual profit with dairy production resulting from a change in one unit of the trait while keeping the others constant and dividing the value by the number of cows. After the EVs were known, ten economic selection indices were estimated for each system so they could be compared by modifying the selection criteria and calculating the relative importance of each selection criteria, the accuracy of the economic selection index, and response expected to the selection in USD, among other parameters. One of the systems detected was called less intensive (LS) and was characterized by having ten cows in lactation that produced 13·5 l/d and consumed 1·8 kg of concentrate/d. The second system detected was called more intensive (IS) and had 22 cows in lactation that produced 17·5 l/d and consumed 3·4 kg of concentrate/d. Monthly profits per cows in lactation of USD 2·60 and USD 68·77 were recorded for LS and IS, respectively. The EVs of the traits MY, FP, and PP were all positive, while for the other traits they were all negative in all situations. The best economic selection indices were those featuring selection criteria MY, LW, and CI, while the trait LW had the greatest importance in both systems. These results indicate that animal frame must be controlled in order to maximize the system's profit.
Severe aortic stenosis with symptoms or left ventricular dysfunction has commonly a poor prognosis and therefore, aortic valve replacement is usually performed for patients aiming at improving their functional class and survival rate.
This retrospective study evaluated a convenience sample of patients at high risk for open surgery for the correction of aortic valve dysfunction treated with TAVI from 2013 to 2018. Data from a private healthcare organization in Belo Horizonte, Brazil were used to assess all-cause mortality. Continuous variables were expressed as mean and standard deviation. Cox proportional regression model and Log-Rank test were used to adjust the survival curve.
Fifty-two patients were included in the study (mean 83 ± 5.7 years of age, range 67 to 93 years; female 55.8 percent). Patients were characterized by: left ventricular ejection fraction (n = 30; mean 52.9 percent, range 26 to 81 percent); aortic valve area (n = 36; mean 0.68 cm2, range 0.4 to 1.2 cm2); left atrium size (n = 14; range 30 to 61 ml/m2); pulmonary artery pressure (n = 20; mean 53 mmHg, range 31 to 70 mmHg). Death occurred in 19 patients during the follow-up period (mean 8.4 months, range 0 to 60 months). Nine deaths occurred within the first 30 days of follow-up (17.3 percent) and 14 (26.9 percent) in the first year. Stroke occurred in three patients (5.8 percent) in the post-implant period. A pacemaker device was required for nine patients (17.3 percent).
Transcatheter aortic valve implantation (TAVI) has become an alternative to surgical aortic valve replacement for patients at high risk for surgery. Real-world studies might result in a better understanding of the local team expertise on TAVI utilization.
Open repair was considered for several years the gold standard therapy for the treatment of peripheral artery aneurysms (PAAs). However, with advancements in endovascular technology increasing attention has been directed toward repairing PAAs using an endovascular stent graft.
This retrospective study evaluated a cohort of patients after the correction of PAAs with Viabahn. Patients treated from January 2011 to January 2018 were assessed for all-cause mortality, amputation and the need for re-intervention. Data were extracted from an administrative database from a healthcare organization in Belo Horizonte, Brazil.
Fifty-two patients were included in the study (median age 69.1 years, range 15 to 90 years; male 63.5 percent), three of whom also received Viabahn for contralateral PAAs. In total, 84 devices were used (average 1.5 per PAA); distribution: popliteal and tibial arteries (n = 30; 57 percent), femoral and iliac arteries (n = 19; 37 percent), axillary artery (n = 1; 2 percent), splenic artery (n = 1; 2 percent), abdominal aorta (n = 1; 2 percent). After a mean follow up time of 1.98 ± 1.68 years, we observed death (n = 3; 5.8 percent), amputation (n = 3; 5.8 percent) and the need for re-intervention (n = 17; 32.6 percent) in 23 patients (44.2 percent). The combined overall survival for the first, second and third year of follow up was 70.2 percent (Confidence Interval [95% CI]: 58.9 - 83.6); 63 percent (95% CI: 51.0 - 78.0) and 57.3 percent (95% CI 44.6 - 73.6).
There are still several unanswered questions regarding the best approach for patients with PAAs. In the absence of well-designed clinical studies, the assessment of databanks on real-world patients may contribute to improve our understanding of treatment alternatives and provide guidance to improve current clinical results.
we construct a measurable subset of the unit ball in
that does not contain pairs of points at distance 1 and whose volume is greater than
times the volume of the unit ball. This disproves a conjecture of Larman and Rogers from 1972.
Many patients presenting with arrhythmias are treated with antiarrhythmic drug therapy. However, for some patients, usually survivors of previous serious ventricular arrhythmias, treatment implies the use of implantable cardioverter defibrillators (ICDs) and/or Cardiac Resynchronization Therapy (CRT) devices.
This retrospective study evaluated a cohort of patients with arrhythmia requiring the use of ICDs, CRT or ICDs + CRT from January 2004 to March 2018. Data from a private healthcare organization in Belo Horizonte, Brazil were used to assess all-cause mortality and the need for replacement of the device. Continuous variables were expressed as mean and standard deviation. Cox proportional regression model and Log-Rank test were used to adjust the survival curve.
Five hundred and ninety-three patients were included in the study (median age 67.6 years, range 23 to 89 years; male 62 percent). According to the type of device used to treat these patients, the distribution was 338 (57.0 percent), 169 (28.5 percent), 86 (14.5 percent), for ICDs, ICDs + CRT, CRT, respectively. After a mean follow-up time of 3.12 years (range 0 to 13.6 years), 283 devices were replaced (ICDs n = 140; ICDs + CRT n = 90; CRT n = 53) and 284 deaths occurred (median survival of 6.9 years). The median survival was 7.3, 5.8, 4.8, 5.5 years for ICDs single-chamber, ICDs dual-chamber, ICDs + CRT, CRT, respectively.
Randomized trials are often criticized for their enrollment of highly selected patients. Studies on real-word data can provide reliable information regarding the use of ICDs and/or CRT devices in the treatment of patients with serious ventricular arrhythmias.
Bariatric surgery has become one of the fastest growing operative procedures due to its sustained results and the increasing prevalence of obesity worldwide. Despite this fact, bariatric surgery carries the usual risks and threats of surgical interventions and therefore its benefits might be undermined by its mid and long-term complications.
This retrospective study included obese patients requiring bariatric surgery from January 2004 to December 2017 provided by a private healthcare organization in Belo Horizonte, Brazil. Data regarding healthcare utilization were extracted from an administrative database (software Oracle Business Intelligence). Continuous variables were expressed as mean and standard deviation. Log-Rank test was used to adjust the survival curve (software STATA 13.1, Stata Corp, USA). This historical cohort resulted in no interventions, neither during the instituted treatment nor after the observed outcome. Privacy of subjects and the confidentiality of their personal information were handled in accordance with the ethical principles of the Declaration of Helsinki.
In total, 16,786 patients were included in the study (mean age 37.2 ± 10.2 years; female 79.2 percent; mean body mass index 42.4 ± 5.5 kg/m2). Patients were followed for up to seven years before and after surgery (total of 78,113 patients/year). For this group, the hospitalization rate was 0.099 / patients-year before versus 0.151 / patients-year after the bariatric surgery (p < 0.001). There were 224 deaths (1.33 percent) identified during the follow-up period, 0.4 percent in the first 30 postoperative days. The average costs for hospitalization were USD 3,339.36 and USD 4,305.04 for open and laparoscopic surgery, respectively.
Bariatric surgery has been an increasingly popular choice in the management of obesity. In our sample, it did not reduce the overall mid-term healthcare utilization rate.
Recent open-label trials show that psychedelics, such as ayahuasca, hold promise as fast-onset antidepressants in treatment-resistant depression.
To test the antidepressant effects of ayahuasca, we conducted a parallel-arm, double-blind randomized placebo-controlled trial in 29 patients with treatment-resistant depression. Patients received a single dose of either ayahuasca or placebo. We assessed changes in depression severity with the Montgomery-Åsberg Depression Rating Scale (MADRS) and the Hamilton Depression Rating scale at baseline, and at 1 (D1), 2 (D2), and 7 (D7) days after dosing.
We observed significant antidepressant effects of ayahuasca when compared with placebo at all-time points. MADRS scores were significantly lower in the ayahuasca group compared with placebo at D1 and D2 (p = 0.04), and at D7 (p < 0.0001). Between-group effect sizes increased from D1 to D7 (D1: Cohen's d = 0.84; D2: Cohen's d = 0.84; D7: Cohen's d = 1.49). Response rates were high for both groups at D1 and D2, and significantly higher in the ayahuasca group at D7 (64% v. 27%; p = 0.04). Remission rate showed a trend toward significance at D7 (36% v. 7%, p = 0.054).
To our knowledge, this is the first controlled trial to test a psychedelic substance in treatment-resistant depression. Overall, this study brings new evidence supporting the safety and therapeutic value of ayahuasca, dosed within an appropriate setting, to help treat depression. This study is registered at http://clinicaltrials.gov (NCT02914769).
Selenium (Se) is an essential micronutrient for humans, yet its dietary intake is low, mostly due to the low bioavailability in soils and therefore in edible plant tissues. To overcome Se deficiency, the breeding approach (i.e., genetic biofortification), namely in rice, is largely dependent on available Se pools. To ensure the success of genetic biofortification with Se, agronomic biofortification can be accomplished through foliar Se application. Considering this background, the main hypothesis of this work was centered in the foliar application of Se to attain agronomic biofortification of rice crops. This study also aimed to assess the full potential for increasing grain Se concentrations during rice filling, as well as the types of nutrients deposition. An experimental design applying two foliar fertilizers (sodium selenite and sodium selenate) was developed. As test systems, four rice genotypes (Ariete, Albatros, OP1105 and OP1109) were used and the kinetics of micro- and macro-nutrients accumulation and deposition were assessed. Biofortification was performed in field trials for two years with foliar fertilization ranging between 0 and 300 g Se ha−1. At the end of the plant cycle, selenite applications triggered 427- to 884-fold increases in grain Se concentrations among rice genotypes (Albatros > OP1105 > OP1109 > Ariete). The application of selenate also prompted 128- to 347-fold increases in grain Se concentrations in rice crops (Albatros > OP1105 > Ariete > OP1109). Regardless of the foliar fertilizer applied, Se deposition among genotypes occurred throughout the grain without relevant inhibitory effects on yields. In each genotype, micro and macronutrients varied among crop tissues.