Context guides perception by influencing stimulus saliency. Accordingly, in visual cortex, responses to a stimulus are modulated by context, the visual scene surrounding the stimulus. Responses are ...suppressed when stimulus and surround are similar but not when they differ. The underlying mechanisms remain unclear. Here, we use optical recordings, manipulations, and computational modeling to show that disinhibitory circuits consisting of vasoactive intestinal peptide (VIP)-expressing and somatostatin (SOM)-expressing inhibitory neurons modulate responses in mouse visual cortex depending on similarity between stimulus and surround, primarily by modulating recurrent excitation. When stimulus and surround are similar, VIP neurons are inactive, and activity of SOM neurons leads to suppression of excitatory neurons. However, when stimulus and surround differ, VIP neurons are active, inhibiting SOM neurons, which leads to relief of excitatory neurons from suppression. We have identified a canonical cortical disinhibitory circuit that contributes to contextual modulation and may regulate perceptual saliency.
•Visual context modulates the response of SOM oppositely to all other V1 neurons•The VIP-SOM disinhibitory circuit controls the impact of context on V1 responses•The VIP-SOM disinhibitory circuit controls V1 by modulating recurrent excitation•As we predict by modeling, silencing of VIP neurons reduces contextual modulation
Context provides meaning by influencing perception. In the visual world, context is the visual environment surrounding a visual scene. Here, Keller et al. report that a canonical disinhibitory circuit controls the response of mouse visual cortex to a visual stimulus depending on the context within which that stimulus is presented.
Biodiversity-friendly coffee certifications offer a viable way to protect wildlife habitat while providing a financial incentive to farmers. Most studies related to these certifications focus on ...avian habitat requirements and it is not known whether these standards also apply to other wildlife, such as mammals, that inhabit the coffee landscapes. We assessed the non-volant mammalian fauna and their associated habitat requirements in 23 sites representing forest, Bird Friendly® shade, conventional shade, and sun coffee habitats. We used Sherman trap-grids to measure small mammal abundance and richness, while camera traps were set for medium-sized and large mammals. We detected 17 species of mammals, representing 11 families. This preliminary study indicates that coffee farms in this region provide an important refuge for mammalian wildlife. Mammal species density ranked significantly higher in Bird Friendly® coffee sites than other coffee habitats, although there was no significant difference for species richness (using Chao2 estimator) among the habitat types. No significant difference was found in small mammal abundance among the habitat types. We found a higher species density of medium and large mammals in sites with larger, more mature shade trees associated with, but not required by Bird Friendly® certification standards. However, lower strata vegetation (5 cm to 1 m tall), the only vegetation parameter found to increase abundance and density for small mammals, is not specified in the Bird Friendly® standards. Our findings suggest that although the standards devised for avian habitat do benefit mammals, further study is needed on the requirements specific for mammals that could be included to enhance the coffee habitat for mammals that inhabit these coffee landscapes.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The interdiscipline of science and technology studies ('STS') has been characterized by its descriptive analyses of the presumptions and practices of scientific communities, and by numerous ...theoretical internal debates over the proper framework of analysis of science. While STS has not been characterized by a powerful effect on law and government, both of which are consumers of scientific expertise, an opportunity arises for engagement in public policy disputes due to the willful ignorance regarding science in the Trump administration, and the negative effects of political agendas and conflicts of interest therein. The urgent need for reliable expertise in such political contexts is addressed in the so-called third wave of STS that is based on Harry Collins and Rob Evans's innovative 'architecture of expertise.' Two recent book chapters, namely Darrin Durant's essay on ignoring experts and Martin Weinel's essay on counterfeit scientific controversies, serve as practical examples of third-wave theory. Bruno Latour, who was engaged in a debate with Collins (and others in STS) concerning their respective approaches during the 1990s, also recently addressed the need for expertise (particularly climate expertise) in government contexts. Nowadays, Collins and Latour both promote consensus expertise and identify its reliance (for its authority) on science as a trusted institution. This article compares the similarities (and acknowledges the differences) between Collins and Latour with respect to their pragmatic strategies, and concludes that notwithstanding internal debates, STS scholars should join Collins (with Evans) and Latour to look outward toward critique and correction of governments that ignore scientific expertise.
encodes ubiquitin protein ligase E3A, and in neurons its expression from the paternal allele is repressed by the
antisense transcript (
). This leaves neurons susceptible to loss-of-function of ...maternal
. Indeed, Angelman syndrome, a severe neurodevelopmental disorder, is caused by maternal
deficiency. A promising therapeutic approach to treating Angelman syndrome is to reactivate the intact paternal
by suppressing
. Prior studies show that many neurological phenotypes of maternal
knockout mice can only be rescued by reinstating
expression in early development, indicating a restricted therapeutic window for Angelman syndrome. Here, we report that reducing
by antisense oligonucleotides in juvenile or adult maternal
knockout mice rescues the abnormal electroencephalogram (EEG) rhythms and sleep disturbance, two prominent clinical features of Angelman syndrome. Importantly, the degree of phenotypic improvement correlates with the increase of Ube3a protein levels. These results indicate that the therapeutic window of genetic therapies for Angelman syndrome is broader than previously thought, and EEG power spectrum and sleep architecture should be used to evaluate the clinical efficacy of therapies.
Coffee agroforestry is a conservation strategy that has shown promise to support the diversity of bird, bat, and insect communities, but few studies have focused on non-volant mammals in coffee ...farms. We assessed mammal diversity within coffee agroforestry systems in Kodagu, India and investigated the impacts of the non-native shade tree species, Grevillea robusta, on mammal diversity. Twenty farms, with varying amounts of G. robusta planted within the coffee farm, were sampled throughout three rainfall zones during the 4-month study period. We captured six species of small mammals, with indirect methods yielding an additional five species, totaling 11 mammal species. Contrary to current ecological thought, we found that increased amounts of G. robusta did not have a negative impact on either abundance or richness of mammals. Small mammal abundances were higher at farms with greater amounts of herbaceous ground cover and larger, mature shade trees, while small mammal species richness was found to increase with an increase in tree species richness as well as greater amounts of herbaceous ground cover. Additionally, small mammal abundance was higher at coffee farms closer to forested areas. Based on these findings, we suggest the maintenance or cultivation of shade tree richness, mature shade trees, and herbaceous ground cover within coffee farms and preservation of forested areas within the landscape to enhance coffee agroforestry habitat for non-volant mammals. We hope that these habitat requirements will be incorporated into conservation strategies for the promotion of biodiversity within coffee agroforestry systems.
Bisphenol A (BPA) is used to manufacture polycarbonate plastic and epoxy resins, which are used in baby bottles, as protective coatings on food containers, and for composites and sealants in ...dentistry. 4-Nonylphenol (NP) is used to make nonylphenol ethoxylates, nonionic surfactants applied as emulsifying, wetting, dispersing, or stabilizing agents in industrial, agricultural, and domestic consumer products. The potential for human exposure to BPA and NP is high because of their widespread use. We measured BPA and NP in archived urine samples from a reference population of 394 adults in the United States using isotope-dilution gas chromatography/mass spectrometry. The concentration ranges of BPA and NP were similar to those observed in other human populations. BPA was detected in 95% of the samples examined at concentrations ≥ 0.1 μg/L urine; the geometric mean and median concentrations were 1.33 μg/L (1.36 μg/g creatinine) and 1.28 μg/L (1.32 μg/g creatinine), respectively; the 95th percentile concentration was 5.18 μg/L (7.95 μg/g creatinine). NP was detected in 51% of the samples examined ≥ 0.1 μg/L. The median and 95th percentile concentrations were < 0.1 μg/L and 1.57 μg/L (1.39 μg/g creatinine), respectively. The frequent detection of BPA suggests widespread exposure to this compound in residents of the United States. The lower frequency of detection of NP than of BPA could be explained by a lower exposure of humans to NP, by different pharmacokinetic factors (i.e., absorption, distribution, metabolism, elimination), by the fact that 4-n-nonylphenol-the measured NP isomer-represents a small percentage of the NP used in commercial mixtures, or a combination of all of the above. Additional research is needed to determine the best urinary biomarker(s) to assess exposure to NP. Despite the sample population's nonrepresentativeness of the U.S. population (although sample weights were used to improve the extent to which the results represent the U.S. population) and relatively small size, this study provides the first reference range of human internal dose levels of BPA and NP in a demographically diverse human population.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The Neotropical region harbors the world’s most diverse terrestrial plant communities. A key component of this diversity is a range of plant–animal interactions involving frugivory, nectarivory, and ...insectivory. Millions of Neotropical hectares subjected to human land-use systems contain trees that are either planted by land managers or retained from the pre-existing forests. Biodiversity-conservation approaches in these systems are often ineffective because of the unfounded assumption that all plants provide equal benefits for consumers. We propose criteria for tree-species selection based on plant–animal interaction research that could guide decisionmakers. We show that tree-species identity is key for enhancing biodiversity and recommend that selection be guided by the structure of plant–animal interaction networks. We also recommend that selection practices consider the timing of resource production, because the year-round availability of food resources in the Neotropics plays an important role in the adaptive radiation of nectar- and fruit-eating vertebrates.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Biologic monitoring (i.e., biomonitoring) is used to assess human exposures to environmental and workplace chemicals. Urinary biomonitoring data typically are adjusted to a constant creatinine ...concentration to correct for variable dilutions among spot samples. Traditionally, this approach has been used in population groups without much diversity. The inclusion of multiple demographic groups in studies using biomonitoring for exposure assessment has increased the variability in the urinary creatinine levels in these study populations. Our objectives were to document the normal range of urinary creatinine concentrations among various demographic groups, evaluate the impact that variations in creatinine concentrations can have on classifying exposure status of individuals in epidemiologic studies, and recommend an approach using multiple regression to adjust for variations in creatinine in multivariate analyses. We performed a weighted multivariate analysis of urinary creatinine concentrations in 22,245 participants of the Third National Health and Nutrition Examination Survey (1988-1994) and established reference ranges (10th-90th percentiles) for each demographic and age category. Significant predictors of urinary creatinine concentration included age group, sex, race/ethnicity, body mass index, and fat-free mass. Time of day that urine samples were collected made a small but statistically significant difference in creatinine concentrations. For an individual, the creatinine-adjusted concentration of an analyte should be compared with a "reference" range derived from persons in a similar demographic group (e.g., children with children, adults with adults). For multiple regression analysis of population groups, we recommend that the analyte concentration (unadjusted for creatinine) should be included in the analysis with urinary creatinine added as a separate independent variable. This approach allows the urinary analyte concentration to be appropriately adjusted for urinary creatinine and the statistical significance of other variables in the model to be independent of effects of creatinine concentration.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Sustained pollinator services within coffee farms depend substantially on a diverse bee community. While studies have been conducted to understand the impacts of forest proximity and farm level ...management on pollinators, few have examined the interaction between these two spatial scales. We surveyed pollinator communities within 18 sites on a large organic farm surrounded by native forest in southern Costa Rica. We selected sites 0, 50 and 150 m from the forest edge within shaded and sparsely-shaded (sun) portions of the farm to quantify the influence of both shade management and distance to contiguous forest on pollinator communities. Contrary to similar studies, native bees dominated the composition of pollinators on this farm. Overall, pollinator diversity and activity did not differ significantly neither between the shade management types nor among the sites 0, 50 or 150 m from the forest edge. However, pollinator diversity was found to be significantly higher at sun sites near forest (0 m) compared with further away, whereas the diversity was the same for the shade sites regardless of forest proximity. We found that greater numbers of coffee flowers within each site increased bee abundance and flower visitation frequency. Bee abundance was greater in sites with less ground cover and bee diversity and visitation frequencies were higher in sites with greater amounts of shade canopy cover and trees in flower. Based on our results, we suggest including flowering shade trees that provide high levels of canopy cover, maintaining or re-establishing forested areas within or surrounding farms, and eliminating or reducing agrochemical use to increase native pollinator activity and diversity within coffee farms.
•Shortened temperature zone in entrained flow gasifier causes slag transformation.•Transition from anorthite to diopside related to temperature and residual carbon.•A dimensionless number was defined ...to characterize degree of slag polymerization.•A general mechanism is built to optimize slag flow in multiple coal utilization.
Recent research provided deep insight on the coal ash-to-slag transformation characterization during the entrained flow gasification process, with experimentation on a 40 kg/hr (dry basis) coal-fed opposed multi-burner (OMB) entrained flow gasifier and simulation via FactSage™ software. A general mechanism is presented to relate the gasifier design temperature, ash fluid temperature, and operating temperature with the degree of the slag polymerization. The change of the high temperature zone, the corresponding particle residence time in the high temperature zone, and syngas composition have obvious effects on the slag mineral transformation behavior. Mineral types formed on the wall of the gasifier chamber were mainly anorthite (CaAl2Si2O8), aluminum oxide (Al2O3), and calcium sulfide (CaS). These minerals transformed to anorthite and diopside (CaMgSi2O6) at the slag hole zone, while the minerals at the lock hopper were anorthite, orthoclase (KAlSi3O8), quartz (SiO2), gypsum (CaSO4), calcite (CaCO3), and halite (NaCl). FactSage™ predicted minerals as anorthite, diopside, orthoclase, and albite (NaAlSi3O8), etc., where the slag temperature was below the ash fluid temperature and when the ratios of CO/CO2 and (CO + H2)/CO2 were lower than 1.0 and 2.0, respectively. By simulation, residual carbon was found to be the dominant factor over syngas composition to cause mineral transformation, and this was verified experimentally. The Ca-based crystals, typically anorthite, was shifted to diopside, near the slag hole zone, and a linear relationship was found between the content ratios of diopside/(anorthite + diopside), CaO/SiO2, and (CaO + MgO)/SiO2. A dimensionless number, θ, was defined to characterize the changing chemical composition and the degree of slag polymerization, with temperature deviation from the design condition. Three zones of θ were identified and related to the deviation between the actual gasification condition from the design condition. A low slag polymerization degree corresponded with a higher temperature deviation between the actual condition and design condition, and this proved that increased residual carbon content and changing iron valence state increased the mineral types when the slag temperature was below the ash fluid temperature.
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