Human behavior displays hierarchical structure: simple actions cohere into subtask sequences, which work together to accomplish overall task goals. Although the neural substrates of such hierarchy ...have been the target of increasing research, they remain poorly understood. We propose that the computations supporting hierarchical behavior may relate to those in hierarchical reinforcement learning (HRL), a machine-learning framework that extends reinforcement-learning mechanisms into hierarchical domains. To test this, we leveraged a distinctive prediction arising from HRL. In ordinary reinforcement learning, reward prediction errors are computed when there is an unanticipated change in the prospects for accomplishing overall task goals. HRL entails that prediction errors should also occur in relation to task subgoals. In three neuroimaging studies we observed neural responses consistent with such subgoal-related reward prediction errors, within structures previously implicated in reinforcement learning. The results reported support the relevance of HRL to the neural processes underlying hierarchical behavior.
► In hierarchical tasks, temporal-difference prediction errors occur with subgoals ► These signals are clearest in cingulate and insular cortices ► Subgoal PEs may also occur in amygdala, habenula, and nucleus accumbens ► Subgoal PEs may represent a neural signature of hierarchical reinforcement learning
In this report from Brazil, evidence of Zika virus transmission from a platelet donor to two patients is presented.
To the Editor:
Zika virus (ZIKV) is a mosquito-borne virus that has important ...secondary means of transmission that include perinatal and sexual modes.
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The potential for transmission in transfused donated blood components has been a concern owing to the detection of ZIKV viremia in healthy blood donors.
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This report from Brazil describes two cases of likely ZIKV transmission by blood transfusion from one presymptomatic infected person who donated platelets by apheresis on January 16, 2016. The two leukodepleted platelet units were irradiated with 25 Gy delivered by an IBL-437C gamma irradiator (Cis Bio International) and were transfused in different . . .
Proto-cooperation between Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus is one of the key factors that determine the fermentation process and final quality of yoghurt. In ...this study, the interaction between different proteolytic strains of S. thermophilus and L. delbrueckii subsp. bulgaricus was investigated in terms of microbial growth, acidification and changes in the biochemical composition of milk during set-yoghurt fermentation. A complementary metabolomics approach was applied for global characterization of volatile and non-volatile polar metabolite profiles of yoghurt associated with proteolytic activity of the individual strains in the starter cultures. The results demonstrated that only non-proteolytic S. thermophilus (Prt−) strain performed proto-cooperation with L. delbrueckii subsp. bulgaricus. The proto-cooperation resulted in significant higher populations of the two species, faster milk acidification, significant abundance of aroma volatiles and non-volatile metabolites desirable for a good organoleptic quality of yoghurt. Headspace SPME-GC/MS and 1H NMR resulted in the identification of 35 volatiles and 43 non-volatile polar metabolites, respectively. Furthermore, multivariate statistical analysis allows discriminating set-yoghurts fermented by different types of starter cultures according to their metabolite profiles. Our finding underlines that selection of suitable strain combinations in yoghurt starters is important for achieving the best technological performance regarding the quality of product.
•S. thermophilus Prt+ did not show associative interaction with L. bulgaricus.•Only S. thermophilus Prt− performed proto-cooperation with L. bulgaricus.•Non-volatile polar metabolite profile of yoghurt was revealed by 1H NMR.•Overall yoghurt metabolite profile was determined by combining GC/MS and 1H NMR.•Multivariate analysis allows discriminating yoghurts based on metabolite profile.
The sepsis burden on acute care services in middle-income countries is a cause for concern. We estimated incidence, prevalence, and mortality of sepsis in adult Brazilian intensive care units (ICUs) ...and association of ICU organisational factors with outcome.
We did a 1-day point prevalence study with follow-up of patients in ICU with sepsis in a nationally representative pseudo-random sample. We produced a sampling frame initially stratified by geographical region. Each stratum was then stratified by hospitals' main source of income (serving general public vs privately insured individuals) and ICU size (ten or fewer beds vs more than ten beds), finally generating 40 strata. In each stratum we selected a random sample of ICUs so as to enrol the total required beds in 1690 Brazilian adult ICUs. We followed up patients until hospital discharge censored at 60 days, estimated incidence from prevalence and length of stay, and generated national estimates. We assessed mortality prognostic factors using random-effects logistic regression models.
On Feb 27, 2014, 227 (72%) of 317 ICUs that were randomly selected provided data on 2632 patients, of whom 794 had sepsis (30·2 septic patients per 100 ICU beds, 95% CI 28·4–31·9). The ICU sepsis incidence was 36·3 per 1000 patient-days (95% CI 29·8–44·0) and mortality was observed in 439 (55·7%) of 788 patients (95% CI 52·2–59·2). Low availability of resources (odds ratio OR 1·67, 95% CI 1·02–2·75, p=0·045) and adequacy of treatment (OR 0·56, 0·37–0·84, p=0·006) were independently associated with mortality. The projected incidence rate is 290 per 100 000 population (95% CI 237·9–351·2) of adult cases of ICU-treated sepsis per year, which yields about 420 000 cases annually, of whom 230 000 die in hospital.
The incidence, prevalence, and mortality of ICU-treated sepsis is high in Brazil. Outcome varies considerably, and is associated with access to adequate resources and treatment. Our results show the burden of sepsis in resource-limited settings, highlighting the need to establish programmes aiming for sepsis prevention, early diagnosis, and adequate treatment.
Fundação de Apoio a Pesquisa do Estado de São Paulo (FAPESP).
The function of midcingulate cortex (MCC) remains elusive despite decades of investigation and debate. Complicating matters, individual MCC neurons respond to highly diverse task-related events, and ...MCC activation is reported in most human neuroimaging studies employing a wide variety of task manipulations. Here we investigate this issue by applying a model-based cognitive neuroscience approach involving neural network simulations, functional magnetic resonance imaging, and representational similarity analysis. We demonstrate that human MCC encodes distributed, dynamically evolving representations of extended, goal-directed action sequences. These representations are uniquely sensitive to the stage and identity of each sequence, indicating that MCC sustains contextual information necessary for discriminating between task states. These results suggest that standard univariate approaches for analyzing MCC function overlook the major portion of task-related information encoded by this brain area and point to promising new avenues for investigation.
Patients with refractory severe aplastic anemia (SAA) who lack a matched sibling or unrelated donor need new therapeutic approaches. Hematopoietic SCT (HSCT) using mismatched or haploidentical ...related donors has been used in the past, but was associated with a significant risk of GVHD and mortality. Recently, the use of post-transplant cyclophosphamide (Cy) has been shown to be an effective strategy to prevent GVHD in recipients of haploidentical HSCT, but the majority of reports have focused on patients with hematology malignancies. We describe the outcome of 16 patients who underwent haploidentical transplantation using a reduced-intensity conditioning regimen with post-transplant Cy. Stem cell sources were BM (N=13) or PBSCs (N=3). The rate of neutrophil engraftment was 94% and of platelet engraftment was 75%. Two patients had secondary graft failure and were successfully salvaged with another transplant. Three patients developed acute GVHD being grades 2-4 in two. Five patients have died and the 1-year OS was 67.1% (95% confidence interval: 36.5-86.4%). In our small series, the use of a reduced-intensity conditioning with post-transplant Cy in haploidentical BMT was associated with high rates of engraftment and low risk of GVHD in patients with relapsed/refractory SAA.
Salmonellosis is associated with the consumption of raw vegetables and fruits such as tomatoes, watermelons, alfalfa sprouts, radishes, carrots, lettuce and parsley. The influence of the fruits' ...roughness on bacterial adhesion was evaluated as measured using a profilometer. The adhesion of Salmonella enterica serovar Typhimurium to mango and tomato surfaces was also evaluated by measuring of the hydrophobicity of the microorganisms and the fruits surfaces. The bacteria adherent on fruit's surface was quantified by plate count and visualize by scanning electron microscopy. In addition, the efficiency of surfactin in removing S. Typhimurium from the fruits' surfaces was analyzed. The average roughness (Ra) of mango (4.54±1.95μm) was significantly different (p<0.05) compared to tomato (2.88±2.15μm). The adhesion of the microorganisms to the fruits' surfaces, as predicted by a determination of the total energy of adhesion (ΔG), was thermodynamically unfavorable. Despite these data, the numbers of bacteria on both fruits' surfaces were similar (p>0.05), reaching 5.95±0.36logCFUcm−2 and 5.81±0.39logCFUcm−2 on mango and tomato, respectively. Therefore, these results suggest that the adhesion observed in this experiment is a multifactorial process. Surfactin removed 94.3% and 92.2% of the S. Typhimurium adhered to the surfaces of the mangoes and tomatoes, respectively. Our research showed that the roughness and hydrophobicity of the fruits' surface did not affect the efficiency of each sanitation treatments on removing of S. Typhimurium. It was observed that the chlorine was more efficient treatment (p<0.05) for tomato surface. For surface of mangoes, chorine and surfactin were better than water treatment for bacteria control.
•Adhesion of microorganisms to fruits' surfaces was thermodynamically unfavorable.•The adhesion observed in this experiment is a multifactorial process.•Roughness and hydrophobicity did not affect the efficiency of sanitation treatment.•Chorine and surfactin were better treatment for bacteria control on mangoes.
A longstanding view of the organization of human and animal behavior holds that behavior is hierarchically organized—in other words, directed toward achieving superordinate goals through the ...achievement of subordinate goals or subgoals. However, most research in neuroscience has focused on tasks without hierarchical structure. In past work, we have shown that negative reward prediction error (RPE) signals in medial prefrontal cortex (mPFC) can be linked not only to superordinate goals but also to subgoals. This suggests that mPFC tracks impediments in the progression toward subgoals. Using fMRI of human participants engaged in a hierarchical navigation task, here we found that mPFC also processes positive prediction errors at the level of subgoals, indicating that this brain region is sensitive to advances in subgoal completion. However, when subgoal RPEs were elicited alongside with goal-related RPEs, mPFC responses reflected only the goal-related RPEs. These findings suggest that information from different levels of hierarchy is processed selectively, depending on the task context.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The objective was to determine the accuracy of a pregnancy test for predicting nonpregnant cattle based on the evaluation of corpus luteum (CL) blood flow at 20d (CLBF-d20) after timed artificial ...insemination (TAI). Crossbred Holstein-Gir dairy heifers (n=209) and lactating cows (n=317) were synchronized for TAI using the following protocol: intravaginal implant (1.0g of progesterone) and 2mg of estradiol benzoate i.m. on d −10, implant removal and 0.526mg of sodium cloprostenol i.m. on d −2, 1mg of estradiol benzoate i.m. on d −1, and TAI on d 0. On d 20, animals underwent grayscale ultrasonography (US) to locate the CL and color flow Doppler to evaluate CLBF-d20 using a portable ultrasound equipped with a 7.5-MHz rectal transducer. Based only on a visual, subjective CLBF evaluation, the animals were classified as pregnant or not pregnant. On d 30 to 35, blinded from results of the previous diagnosis, the same operator performed a final pregnancy diagnosis using US to visualize the fetal heartbeat (gold standard; US-d30). A second evaluator also analyzed the CLBF-d20 in the same animals by watching 7-s recorded videos. Blood samples were collected from a subset of 171 females to determine, by RIA, plasma progesterone (P4) concentrations, which indicate CL function. The final pregnancy outcome (US-d30) was retrospectively compared with the CLBF-d20 diagnoses and then classified either as correct or incorrect. The number of true positive, true negative, false positive, and false negative decisions were inserted into a 2×2 decision matrix. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the CLBF-d20 test were calculated using specific equations. Binomial variables (pregnancy rate and proportions) were analyzed using Fisher’s exact test for the effect of parity and to compare between evaluators and tests (CLBF-d20 vs. plasma P4). The kappa values were calculated to quantify the agreement between CLBF-d20 and the gold standard (US-d30) and between evaluators. The performance parameters of CLBF-d20 test were as follows: sensitivity=99.0%, specificity=53.7%, positive predictive value=65.1%, negative predictive value=98.5%, and accuracy=74.8%. False negatives represented only 0.4% of the exams. No differences existed in these parameters between evaluators (no. 1 vs. no. 2) and tests (CLBF-d20 vs. plasma P4). Moreover, a high level of agreement was observed between evaluators (0.91). In conclusion, visual evaluation of CLBF-d20 represents a quick, reliable, and consistent diagnostic test that enables the early detection of nonpregnant cattle.
•We explored how changes in climate may affect the spatial distribution of areas suitable for coffee production in 2050.•The area suitable for coffee production with unshaded plantations may decline ...by 60% under projected climate change.•Agroforestry systems can mitigate the effects of climate change and maintain 75% of the area suitable for coffee production.•Identifying coffee production areas that are vulnerable to climate change may direct climate adaptation management actions.
Climate change may impose severe challenges to farmers to maintain agricultural production levels in the future. In this study we analysed the effect of projected changes in climate on the area suitable for coffee production in 2050, and the potential of agroforestry systems to mitigate these effects in a major coffee production region in southeast Brazil. We conducted a spatially explicit analysis with the bioclimatic model MaxEnt to explore the area that is suitable for coffee production in 2050 when coffee is grown in unshaded plantations and in agroforestry systems. The projected climate in 2050 was assessed using 19 global circulation models, and we accounted for the altered microclimate in agroforestry systems by adjusting the maximum and minimum air temperature. The climate models indicated that the annual mean air temperature is expected to increase 1.7 °C ± 0.3 in the study region, which will lead to almost 60 % reduction in the area suitable for coffee production in unshaded plantations by 2050. However, the adoption of agroforestry systems with 50 % shade cover can reduce the mean temperatures and maintain 75 % of the area suitable for coffee production in 2050, especially between 600 and 800 m altitude. Our study indicates that major shifts in areas suitable for coffee production may take place within three decades, potentially leading to land conflicts for coffee production and nature conservation. Incentives that contribute to the development of coffee agroforestry systems at appropriate locations may be essential to safeguard coffee production in the southeast of Brazil.
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