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1.
Protein Expr Purif ; 221: 106516, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38801985

RESUMO

Galectins are a large and diverse protein family defined by the presence of a carbohydrate recognition domain (CRD) that binds ß-galactosides. They play important roles in early development, tissue regeneration, immune homeostasis, pathogen recognition, and cancer. In many cases, studies that examine galectin biology and the effect of manipulating galectins are aided by, or require the ability to express and purify, specific members of the galectin family. In many cases, E. coli is employed as a heterologous expression system, and galectin expression is induced with isopropyl ß-galactoside (IPTG). Here, we show that galectin-3 recognizes IPTG with micromolar affinity and that as IPTG induces expression, newly synthesized galectin can bind and sequester cytosolic IPTG, potentially repressing further expression. To circumvent this putative inhibitory feedback loop, we utilized an autoinduction protocol that lacks IPTG, leading to significantly increased yields of galectin-3. Much of this work was done within the context of a course-based undergraduate research experience, indicating the ease and reproducibility of the resulting expression and purification protocols.


Assuntos
Escherichia coli , Galectina 3 , Isopropiltiogalactosídeo , Galectina 3/genética , Galectina 3/metabolismo , Galectina 3/biossíntese , Galectina 3/química , Escherichia coli/genética , Escherichia coli/metabolismo , Humanos , Isopropiltiogalactosídeo/farmacologia , Expressão Gênica , Galectinas/genética , Galectinas/metabolismo , Galectinas/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Sanguíneas/genética , Proteínas Sanguíneas/metabolismo
2.
R I Med J (2013) ; 107(1): 12-14, 2024 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-38166068

RESUMO

Spontaneous community-acquired meningitis caused by E. coli is rare in the adult population. It is associated with a high risk of morbidity and mortality. We describe a case of a 72-year-old woman who presented with altered mental status and neck stiffness and was found to have E. coli meningitis. Urine cultures grew E. coli, representing a likely source. The E. coli strain was identified as sequence type 73 (E. coli ST73). Her symptoms and laboratory values improved following antibiotic initiation, and she was discharged from the hospital to a rehabilitation facility.


Assuntos
Infecções por Escherichia coli , Meningite devida a Escherichia coli , Meningite , Idoso , Feminino , Humanos , Antibacterianos/uso terapêutico , Escherichia coli , Infecções por Escherichia coli/diagnóstico , Infecções por Escherichia coli/tratamento farmacológico , Meningite/diagnóstico , Meningite/tratamento farmacológico , Meningite/etiologia , Meningite devida a Escherichia coli/diagnóstico , Meningite devida a Escherichia coli/complicações , Meningite devida a Escherichia coli/tratamento farmacológico
3.
J Pediatr Orthop ; 44(1): e91-e96, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-37820256

RESUMO

INTRODUCTION: Amid a national opioid epidemic, it is essential to review the necessity of opioid prescriptions. Research in adults has demonstrated patients often do not use their entire postoperative opioid prescription. Limited data suggest that the trend is similar in children. This study investigated the prescription volume and postoperative utilization rate of opioids among pediatric orthopaedic surgery patients at our institution. METHODS: We identified pediatric patients (ages below 18 y old) who presented to our institution for operating room intervention from May 24, 2021, to December 13, 2021. Patient demographics and opioid prescription volume were recorded. Parents and guardians were surveyed by paper "opioid diary" or phone interview between postoperative days 10 to 15, assessing pain level, opioid use, and plans for remaining opioid doses. Wilcoxon rank-sum test, Independent t test, and Pearson correlation were used for the analysis of continuous variables. Multivariable logistic regression was used to control for patient demographic variables while analyzing opioid usage relationships. RESULTS: Prescription volume information was collected for 280 patients during the study period. We were able to collect utilization information for 102 patients (Group 1), whereas the remaining 178 patients contributed only prescription volume data (Group 2). Patients with upper extremity fractures received significantly fewer opioid doses at discharge compared with other procedure types ( P =0.036). Higher BMI was positively correlated with more prescribed opioid doses ( R2 =0.647, P <0.001). The mean opioid utilization rate was 22.37%. A total of 50.6% of patients prescribed opioids at discharge used zero doses. A total of 96.2% of patients used opioids for 5 days or less. Most families had not disposed of excess medication by postoperative day 10. CONCLUSIONS: We found significant differences in opioid prescribing practices based on patient and procedure-specific variables. In addition, although our pediatric orthopaedic surgery patients had low overall rates of postoperative opioid utilization, there was significant variation in opioid use among procedure types. These results provide insights that can guide opioid prescribing practices for pediatric orthopaedic patients and promote patient education to ensure safe opioid disposal.


Assuntos
Transtornos Relacionados ao Uso de Opioides , Procedimentos Ortopédicos , Ortopedia , Adulto , Criança , Humanos , Analgésicos Opioides/uso terapêutico , Prescrições de Medicamentos , Dor Pós-Operatória/tratamento farmacológico , Padrões de Prática Médica
4.
Integr Org Biol ; 5(1): obad028, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37670952

RESUMO

Studies of the Papuan region have provided fundamental insights into the evolutionary processes generating its exceptional biodiversity, but the influence of geological processes merits further study. Lying at the junction of five tectonic plates, this region has experienced a turbulent geological history that has not only produced towering mountains allowing elevational specialization and island archipelagos with varying degrees of isolation promoting vicariance, but also active margins where land masses have collided and been subsequently rifted apart creating a mosaic of intermixed terranes with vastly different geological histories. Asterophryine frogs are a hyperdiverse clade representing half the world's microhylid diversity (over 360 species) centered on New Guinea and its satellite islands. We show that vicariance facilitated by geological history explains this far and wide distribution of a clade that should have poor dispersal abilities. We recovered a mainland tectonic unit, the East Papua Composite Terrane (EPCT), as the center of origin for Asterophryinae and no fewer than 71 instances of what appear to be long-distance dispersal events, 29 of which are between mainland regions, with 42 from the mainland to the islands, some presently as far as 200 km away from source populations over open ocean. Furthermore, we find strong support for a "Slow and Steady" hypothesis for the formation of the northern margin of New Guinea by many separate accretion events during the Miocene, over other major geological alternatives, consistent with the 20 M year age of the clade and arrival via the EPCT. In addition, the historical biogeography of our frogs strongly supports an affiliation of the Louisiade Archipelago and Woodlark Island with the Owen Stanley Range on the EPCT, and the recent proximity of the large New Britain Island. Our results show that Asterophryinae did not have to repeatedly and independently disperse across large ocean barriers to the offshore islands, against the predictions of island biogeography theory, but that the current distribution can be explained through vicariance and short-distance oceanic dispersal as historical land connections disappeared and islands slowly became separated from each other. We show that islands have a life history, changing in distance from other land masses, with consequent opportunities for dispersal, isolation, and cladogenesis of their biotas. More broadly, we can begin to see how the geological history of the Papuan region can result in the rapid accumulation and staggering number of extant species.

5.
J Prim Care Community Health ; 14: 21501319231184380, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37381821

RESUMO

INTRODUCTION/OBJECTIVES: While it is well established that unmet healthrelated social needs (HRSN) adversely affect health outcomes, there has been limited evaluation in adult primary care of patients' perceptions of how these needs impact their health and the role of the primary care provider (PCP). The objective of this study is to identify patients' perceptions of HRSN and how PCPs could help address them. Secondary objectives include exploring the impact of goal setting and a 1-time cash transfer (CT). METHODS: This qualitative study used semi-structured baseline and follow-up interviews with patients in internal medicine clinics. Adult primary care patients were included if they screened positive as having 1 of 3 HRSN: financial resource strain, transportation needs, or food insecurity. All participants completed an initial interview about their HRSN and health, and were asked to set a 6-month health goal. At enrollment, participants were randomized to receive a $500 CT or a $50 participation reward. At 6-months, patients were interviewed again to investigate progress toward meeting their health goals, [when applicable] how the CT helped, and their beliefs about the role of PCPs in addressing HRSN. RESULTS: We completed 30 initial and 25 follow-up interviews. Participants identified their HRSN, however most did not readily connect identified needs to health. Although participants were receptive to HRSN screening, they did not feel it was their PCP's responsibility to address these needs. Verbal goal-setting appeared to be a useful tool, and while the CTs were appreciated, patients often found them inadequate to address HRSN. CONCLUSIONS: Given the importance of identifying the social conditions that shape patients' health, providers, and health systems have an opportunity to re-evaluate their role in helping patients address these barriers. Future studies could examine the effect of more frequent disbursement of CTs over time.


Assuntos
Instituições de Assistência Ambulatorial , Humanos , Adulto , Emoções , Pacientes , Atenção Primária à Saúde
6.
Curr Oncol ; 30(4): 3755-3775, 2023 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-37185398

RESUMO

As part of the NCI's Cancer Center Cessation (C3i) initiative, we initiated, expanded, and maintained an evidence-based tobacco treatment program at the Georgetown Lombardi Comprehensive Cancer Center. We present a quality improvement (QI) assessment of the implementation process and patient-level outcomes. At two hematology/oncology outpatient clinical sites, five oncology-based teams (clinical administrators, clinical staff, pharmacy, information technology, and tobacco treatment staff) developed implementation strategies for opt-out patient assessment and enrollment, centralized tobacco treatment, audit, feedback, and staff training. Among eligible patients (tobacco use in ≤30 days), we assessed demographic, clinical, and tobacco-related characteristics to examine predictors of enrollment (baseline completed), treatment engagement (≥one sessions completed), and self-reported 7-day abstinence (6 months post-enrollment). Across both sites, medical assistants screened 19,344 (82.4%) patients for tobacco use, which identified 1345 (7.0%) current tobacco users, in addition to 213 clinician referrals. Of the 687/1256 (54.7%) eligible patients reached, 301 (43.8%) enrolled, and 199 (29.0%) engaged in treatment, of whom 74.5% were African American and 68% were female. At the larger site, significant multivariate predictors of enrollment included African American race (vs. white/other) and clinician referral (vs. MA assessment). Treatment engagement was predicted by greater nicotine dependence, and abstinence (27.4%) was predicted by greater treatment engagement. In summary, the systematic utilization of multiple oncology-based teams and implementation strategies resulted in the development and maintenance of a high-quality, population-based approach to tobacco treatment. Importantly, these strategies addressed inequities in tobacco treatment, as the program reached and engaged a majority-African-American patient population. Finally, the opt-out patient assessment strategy has been implemented in multiple oncology settings at MedStar Health through the Commission on Cancer's Just Ask program.


Assuntos
Abandono do Hábito de Fumar , Humanos , Feminino , Masculino , Abandono do Hábito de Fumar/métodos , Melhoria de Qualidade , Fumar , Uso de Tabaco/terapia , Encaminhamento e Consulta
7.
Biogeochemistry ; 163(3): 245-263, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37155460

RESUMO

River-to-lake transitional areas are biogeochemically active ecosystems that can alter the amount and composition of dissolved organic matter (DOM) as it moves through the aquatic continuum. However, few studies have directly measured carbon processing and assessed the carbon budget of freshwater rivermouths. We compiled measurements of dissolved organic carbon (DOC) and DOM in several water column (light and dark) and sediment incubation experiments conducted in the mouth of the Fox river (Fox rivermouth) upstream from Green Bay, Lake Michigan. Despite variation in the direction of DOC fluxes from sediments, we found that the Fox rivermouth was a net sink of DOC where water column DOC mineralization outweighed the release of DOC from sediments at the rivermouth scale. Although we found DOM composition also changed during our experiments, alterations in DOM optical properties were largely independent of the direction of sediment DOC fluxes. We found a consistent decrease in humic-like and fulvic-like terrestrial DOM and a consistent increase in the overall microbial composition of rivermouth DOM during our incubations. Moreover, greater ambient total dissolved phosphorus concentrations were positively associated with the consumption of terrestrial humic-like, microbial protein-like, and more recently derived DOM but had no effect on bulk DOC in the water column. Unexplained variation indicates that other environmental controls and water column processes affect the processing of DOM in this rivermouth. Nonetheless, the Fox rivermouth appears capable of substantial DOM transformation with implications for the composition of DOM entering Lake Michigan. Supplementary Information: The online version contains supplementary material available at 10.1007/s10533-022-01000-z.

8.
Data Brief ; 47: 108987, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36875215

RESUMO

The data provided here are related to the article "Resolving the Deep Phylogeny: Implications for Early Adaptive Radiation, Cryptic, and Present-day Ecological Diversity of Papuan Microhylid Frogs" [1]. The dataset is based on 233 tissue samples of the subfamily Asteroprhyinae, with representatives from all recognized genera, in addition to three outgroup taxa. The sequence dataset contains over 2400 characters per sample for five genes: three nuclear (Seventh in Absentia (SIA), Brain Derived Neurotrophic Factor (BDNF), Sodium Calcium Exchange subunit-1 (NXC-1)), and two mitochondrial loci (Cytochrome oxidase b (CYTB), and NADH dehydrogenase subunit 4 (ND4)); and is 99% complete. New primers were designed for all loci and accession numbers for the raw sequence data are provided. The sequences are used with geological time calibrations to produce time-calibrated Bayesian inference (BI) and Maximum Likelihood (ML) phylogenetic reconstructions using BEAST2 and IQ-TREE. Lifestyle data (arboreal, scansorial, terrestrial, fossorial, semi-aquatic) were collected from the literature and field notes and used to infer ancestral character states for each lineage. Collection location and elevation data were used to verify sites where multiple species or candidate species co-occur. All sequence data, alignments, and associated metadata (voucher specimen number, species identification, type locality status, global positioning system [GPS] coordinates, elevation, site with species list, and lifestyle) as well as the code to produce all analyses and figures are provided.

9.
Plants (Basel) ; 11(23)2022 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-36501306

RESUMO

Western spruce budworm (Choristoneura freemani Razowski) is the most destructive defoliator of forests in the western US. Forests in northern New Mexico experienced high levels of WSBW-caused defoliation and subsequent mortality between the 1980s and 2010s. The effects of severe western spruce budworm outbreaks on stand dynamics in the US Southwest are still relatively unknown, but understanding the impacts is important to the management and resilience of these forests. To begin addressing this knowledge gap, we conducted a study along two gradients: an elevational gradient from mixed-conifer to spruce-fir forests and a gradient of WSBW-caused defoliation intensity. We recorded overstory and understory stand conditions (size structure, species composition, damaging agents). Western spruce budworm was the primary damaging agent of host trees in all stands andcaused host tree mortality across all size classes, particularly in spruce-fir stands. Results indicate an unsustainable level of mortality in spruce-fir stands and a transition towards non-host species in mixed-conifer stands. Low levels of regeneration coupled with high overstory mortality rates indicate a potential lack of resilience in spruce-fir stands, whereas resilience to future western spruce budworm defoliation events may have increased in mixed-conifer stands affected by these outbreaks.

10.
Mol Phylogenet Evol ; 177: 107618, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36031107

RESUMO

The microhylid frogs of the New Guinea region are the largest and most ecologically diverse subfamily (Asterophryinae) of one of the largest anuran families in the world and can live in communities of up to 20 species. While there has been recent progress in resolving the phylogenetic relationships of Asterophryinae, significant uncertainties remain, impeding further progress in understanding the evolution of microhabitat use, parental care, and life history variation in this group. In particular, the early divergences at the base of the tree remain unclear; as does the monophyly of some genera; and recent studies have discovered that species with wide geographic distribution are instead cryptic species complexes. In this study, we fortified geographic sampling of the largest previous phylogenetic effort by sequencing an additional 62 taxa and increased data quality and quantity by adding new layers of data vetting and by filling in previously incomplete loci to the five gene dataset (2 mitochondrial, 3 nuclear protein-coding genes) to obtain a dataset that is now 99% complete in over 2400 characters for 233 samples (205 taxa) of Asterophryinae and 3 outgroup taxa, and analyzed microhabitat use data for these taxa from field data and data collected from the literature. Importantly, our sampling includes complete community complements at 19 sites as well as representatives at over 80 sites across New Guinea and its offshore islands. We present a highly resolved molecular phylogeny which, for the first time, has over 95% of nodes supported (84% highly supported) whether using Maximum Likelihood or Bayesian Inference, allowing clarification of all genera (whether monophyletic or clearly not), their sister genera relationships, as well as an age estimate for the Asterophryinae at approximately 20MYA. Early generic diversification occurring between 17 and 12 MYA gave rise to a surprising diversity of about 18 genera as well as the 5 putative microhabitat types. Our tree reveals extensive cryptic diversity calling any widespread taxa into doubt, and clearly demonstrates that complex multispecies communities of Asterophryinae are ecologically diverse, are numerous, and of ancient origin across New Guinea. We discuss the implications of our phylogeny for explaining the explosive diversification of Asterophryinae as the result of adaptive radiation, niche conservatism, and non-adaptive radiation.


Assuntos
Anuros , Núcleo Celular , Animais , Anuros/genética , Teorema de Bayes , Núcleo Celular/genética , Humanos , Proteínas Nucleares/genética , Filogenia
11.
Spine (Phila Pa 1976) ; 47(18): 1270-1278, 2022 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-35867612

RESUMO

OBJECTIVE: Considering the high rates of opioid usage following orthopedic surgeries, it is important to explore this in the setting of the current opioid epidemic. This study examined acute opioid poisonings in postoperative spine surgery patients in New York and the rates of poisonings among these patients in the context of New York's 2016 State legislation limiting opioid prescriptions. METHODS: Claims for adult patients who received specific orthopedic spine procedures in the outpatient setting were identified from 2009 to 2018 in the New York Statewide Planning and Research Cooperative System (SPARCS) database. Patients were followed to determine if they presented to the emergency department for acute opioid poisoning postoperatively. Multivariable logistic regression was performed to evaluate the effect of patient demographic factors on the likelihood of poisoning. The impact of the 2016 New York State Public Health Law Section 3331, 5. (b), (c) limiting opioid analgesic prescriptions was also evaluated by comparing rates of poisoning prelegislation and postlegislation enactment. RESULTS: A total of 107,456 spine patients were identified and 321 (0.3%) presented postoperatively to the emergency department with acute opioid poisoning. Increased age [odds ratio (OR)=0.954, P <0.0001] had a decreased likelihood of poisoning. Other race (OR=1.322, P =0.0167), Medicaid (OR=2.079, P <0.0001), Medicare (OR=2.9, P <0.0001), comorbidities (OR=3.271, P <0.0001), and undergoing multiple spine procedures during a single operative setting (OR=1.993, P <0.0001) had an increased likelihood of poisoning. There was also a significant reduction in rates of postoperative acute opioid poisoning in patients receiving procedures postlegislation with reduced overall likelihood (OR=0.28, P <0.0001). CONCLUSION: There is a higher than national average rate of acute opioid poisonings following spine procedures and increased risk among those with certain socioeconomic factors. Rates of poisonings decreased following a 2016 legislation limiting opioid prescriptions. It is important to define factors that may increase the risk of postoperative opioid poisoning to promote appropriate management of postsurgical pain.


Assuntos
Analgésicos Opioides , Procedimentos Ortopédicos , Adulto , Idoso , Analgésicos Opioides/uso terapêutico , Humanos , Medicare , New York/epidemiologia , Procedimentos Ortopédicos/efeitos adversos , Dor Pós-Operatória/tratamento farmacológico , Dor Pós-Operatória/epidemiologia , Estudos Retrospectivos , Estados Unidos
12.
Ecol Appl ; 32(7): e2685, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35633203

RESUMO

Lakes are dynamic ecosystems that can transition among stable states. Since ecosystem-scale transitions can be detrimental and difficult to reverse, being able to predict impending critical transitions in state variables has become a major area of research. However, not all transitions are detrimental, and there is considerable interest in better evaluating the success of management interventions to support adaptive management strategies. Here, we retrospectively evaluated the agreement between time series statistics (i.e., standard deviation, autocorrelation, skewness, and kurtosis-also known as early warning indicators) and breakpoints in state variables in a lake (Lake Simcoe, Ontario, Canada) that has improved from a state of eutrophication. Long-term (1980 to 2019) monitoring data collected fortnightly throughout the ice-free season were used to evaluate historical changes in 15 state variables (e.g., dissolved organic carbon, phosphorus, chlorophyll a) and multivariate-derived time series at three monitoring stations (shallow, middepth, deep) in Lake Simcoe. Time series results from the two deep-water stations indicate that over this period Lake Simcoe transitioned from an algal-dominated state toward a state with increased water clarity (i.e., Secchi disk depth) and silica and lower nutrient and chlorophyll a concentrations, which coincided with both substantial management intervention and the establishment of invasive species (e.g., Dreissenid mussels). Consistent with improvement, Secchi depth at the deep-water stations demonstrated expected trends in statistical indicators prior to identified breakpoints, whereas total phosphorus and chlorophyll a revealed more nuanced patterns. Overall, state variables were largely found to yield inconsistent trends in statistical indicators, so many breakpoints were likely not reflective of traditional bifurcation critical transitions. Nevertheless, statistical indicators of state variable time series may be a valuable tool for the adaptive management and long-term monitoring of lake ecosystems, but we call for more research within the domain of early warning indicators to establish a better understanding of state variable behavior prior to lake changes.


Assuntos
Ecossistema , Lagos , Clorofila A , Monitoramento Ambiental/métodos , Eutrofização , Ontário , Fósforo/análise , Estudos Retrospectivos , Dióxido de Silício , Água
13.
Water Res ; 213: 118109, 2022 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-35203018

RESUMO

More than half of new urban residential developments are planned as infill in Australia's major cities. This provides an unprecedented opportunity to use innovative design and technology to address urban water challenges such as flooding, reduced water security and related infrastructure and urban heat island issues. However, infill can have positive or negative water impacts, depending on architectural design and on-site water servicing technologies implemented. In this study we asked, "What influence does residential infill development have on the local urban water cycle?" and "What roles do architectural design and technologies play?" To answer these questions, a set of 196 design-technology configurations were developed by combining 28 architectural designs and 7 on-site water-servicing technology options. The configurations represent three cases: (i) existing (EX) or before infill, (ii) business-as-usual development (BAU), and (iii) alternative development (ALT). Using the Site-scale Urban Water Mass Balance Assessment (SUWMBA) model and a set of water performance indicators, the impact of configurations on the urban water cycle was quantified. The results showed BAU, on average, increases population density, stormwater discharge, and imported water by 98%, 44% and 85%, and decreases evapotranspiration and infiltration by 53% and 34%, compared to the EX conditions. More population density (141%) with lower impacts on the urban water cycle (21% and 64% increase for stormwater discharge and imported water, and 29% and 17% reduction in evapotranspiration and infiltration) can be achieved by appropriate integration of ALT designs and technologies. Architectural design has a greater influence on urban water flows than the implementation of on-site water servicing technologies. The results have a great implication for sustainable urban water management for managing the risks associated with pluvial flooding, water insecurity, and urban heat. It also highlights the underutilised role of architects and urban planners to address urban water issues.

15.
Ecol Appl ; 31(8): e02447, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34448320

RESUMO

Concentration-discharge (C-Q) relationships have been widely used to assess the hydrochemical processes that control solute fluxes from streams. Here, using a large regional dataset we assessed long-term C-Q relationships for total phosphorus (TP), soluble reactive phosphorus (SRP), total Kjeldahl nitrogen (TKN), and nitrate (NO3 ) for 63 streams in Ontario, Canada, to better understand seasonal regional behavior of nutrients. We used C-Q plots, Kruskal-Wallis tests, and breakpoint analysis to characterize overall regional nutrient C-Q relationships and assess seasonal effects, anthropogenic impacts, and differences between "rising" and "falling" hydrograph limbs to gain an understanding of the dominant processes controlling overall C-Q relationships. We found that all nutrient concentrations were higher on average in catchments with greater levels of anthropogenic disturbance (agricultural and urban land use). TP, SRP, and TKN showed similar C-Q dynamics, with nearly flat or gently sloping C-Q relationships up to a discharge threshold after which C-Q slopes substantially increased during the rising limb. These thresholds were seasonally variable, with summer and winter thresholds occurring at lower flows compared with autumn and greater variability during snowmelt. These patterns suggest that seasonal strategies to reduce high flows, such as creating riparian wetlands or reservoirs, in conjunction with reducing related nutrient transport during high flows would be the most effective way to mitigate elevated in-stream concentrations and event export. Elevated rising limb concentrations suggest that nutrients accumulate in upland parts of the catchment during drier periods and that these are released during rain events. NO3 C-Q patterns tended to be different from the other nutrients and were further complicated by anthropogenic land use, with greater reductions on the falling limb in more disturbed catchments during certain seasons. There were few significant NO3 hydrograph limb differences, indicating that there was likely to be no dominant hysteretic pattern across our study region due to variability in hysteresis from catchment to catchment. This suggests that this nutrient may be difficult to successfully manage at the regional scale.


Assuntos
Monitoramento Ambiental , Rios , Agricultura , Nitrogênio/análise , Ontário , Fósforo/análise , Chuva , Rios/química
16.
Nature ; 593(7860): 528-534, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-34040212

RESUMO

Van der Waals heterostructures display numerous unique electronic properties. Nonlocal measurements, wherein a voltage is measured at contacts placed far away from the expected classical flow of charge carriers, have been widely used in the search for novel transport mechanisms, including dissipationless spin and valley transport1-9, topological charge-neutral currents10-12, hydrodynamic flows13 and helical edge modes14-16. Monolayer1-5,10,15-19, bilayer9,11,14,20 and few-layer21 graphene, transition-metal dichalcogenides6,7 and moiré superlattices8,10,12 have been found to display pronounced nonlocal effects. However, the origin of these effects is hotly debated3,11,17,22-24. Graphene, in particular, exhibits giant nonlocality at charge neutrality1,15-19, a striking behaviour that has attracted competing explanations. Using a superconducting quantum interference device on a tip (SQUID-on-tip) for nanoscale thermal and scanning gate imaging25, here we demonstrate that the commonly occurring charge accumulation at graphene edges23,26-31 leads to giant nonlocality, producing narrow conductive channels that support long-range currents. Unexpectedly, although the edge conductance has little effect on the current flow in zero magnetic field, it leads to field-induced decoupling between edge and bulk transport at moderate fields. The resulting giant nonlocality at charge neutrality and away from it produces exotic flow patterns that are sensitive to edge disorder, in which charges can flow against the global electric field. The observed one-dimensional edge transport is generic and nontopological and is expected to support nonlocal transport in many electronic systems, offering insight into the numerous controversies and linking them to long-range guided electronic states at system edges.

17.
Water Res ; 188: 116477, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33137527

RESUMO

Historically, little consideration has been given to water performance of urban developments such as "hydrological naturalness" or "local water self-sufficiency". This has led to problems with increased stormwater runoff, flooding, and lack of local contributions to urban water security. Architectural design, water servicing technologies and environmental conditions are each known to influence water performance. However, most existing models have overlooked the integration of these factors. In this work, we asked 'how the water performance of urban developments at site-scale can be quantified, with joint consideration of architectural design, water servicing technologies, and environmental context (i.e. climate and soil)'. Answering this question led to the development of a new method and tool called Site-scale Urban Water Mass Balance Assessment (SUWMBA). It uses a daily urban water mass balance to simulate design-technology-environment configurations. Key features include: (i) a three-dimensional boundary focussed on the "entity" of development (ii) a comprehensive water balance accounting for all urban water flows, (iii) methods that include key variables capturing the interactions of natural, built-environment and socio-technological systems on water performance. SUWMBA's capabilities were demonstrated through an evaluation of a residential infill development case study with alternative design-technology-environment configurations, combining three dwelling designs, seven water technologies and three environmental contexts. The evaluation showed how a configuration can be identified that strikes a balance between the conflicting objectives of achieving the desired dwelling densities whilst simultaneously improving water performance. For two climate zones, the optimal configuration increases the total number of residents by 300% while reducing the imported water per capita and stormwater discharge by 45% and 15%, respectively. We infer that SUWMBA could have strong potential to contribute to performance-based urban design and planning by enabling the water performance of dwelling designs to be quantified, and by facilitating the setting of locally-specific water performance objectives and targets.


Assuntos
Conservação dos Recursos Naturais , Abastecimento de Água , Cidades , Hidrologia , Chuva , Tecnologia , Água
18.
Front Microbiol ; 11: 568629, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33304327

RESUMO

In aquatic ecosystems, dissolved organic matter (DOM) composition is driven by land use, microbial activity, and seasonal variation in hydrology and water temperature, and, in turn, its microbial bioavailability is expected to vary due to differences in its composition. It is commonly assumed that DOM of terrestrial origin is resistant to microbial activity because it is composed of more complex aromatic compounds. However, the effect of DOM sources on the microbial reworking and degradation of the DOM pool remains debated. We performed laboratory incubation experiments to examine how temporal changes in DOM composition influence its microbial biodegradability in two contrasting streams (agricultural and forested) in southern Ontario, Canada. Despite a more allochthonous-like DOM signature in the forest stream and a more autochthonous-like DOM signature in the agriculture stream, we found that biodegradation and production of DOC were the same in both streams and synchronous throughout the sampling period. However, the initial DOM composition impacted how the DOM pool changed upon degradation. During the incubations, both autochthonous-like and allochthonous-like fractions of the DOM pool increased. We also found that a greater change in DOM composition during the incubations induced higher degradation of carbon. Finally, temporal variation in DOC biodegradation and production over time or across streams was not related to DOM composition, although there was a significant relationship between BDOC and nutrient concentrations in the agriculture stream. This observation potentially challenges the notion that DOM origin predicts its bioavailability and suggests that broad environmental factors shape DOC consumption and production in aquatic ecosystems. More research is needed to better understand the drivers of microbial biodegradability in streams, as this ultimately determines the fate of DOM in aquatic ecosystems.

19.
Arch Environ Contam Toxicol ; 79(3): 283-297, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33063196

RESUMO

Silver nanoparticles (AgNP) are widely used as antibacterial agents in both commercial products and for industrial applications. As such, AgNP has a high potential for release into freshwater environments. As part of a whole-lake ecosystem experiment to examine the impacts of AgNP exposure at low µg/L concentrations over multiple years, we evaluated biological responses in Yellow Perch (Perca flavescens) before, during, and after AgNP additions to a freshwater lake. Yellow Perch were monitored for responses to in situ AgNP additions at the cellular (suite of biomarkers), individual (growth, prey consumption, and metabolism), and population (abundance and gross prey consumption) scales. At the cellular level, several biomarkers of oxidative stress in liver tissues revealed down-regulation, including decreased mRNA levels of catalase and glutathione peroxidase in Yellow Perch collected during AgNP exposure, and elevated ratios of reduced to oxidized glutathione. At the individual level, Yellow Perch bioenergetic models revealed that prey consumption and total metabolism significantly declined during AgNP additions and remained depressed one year after AgNP addition. At the population level, Yellow Perch densities and gross prey consumption declined after AgNP was added to the lake. Together, these results reveal a holistic assessment of the negative impacts of chronic exposure to environmentally relevant AgNP concentrations (i.e., µg/L) on Yellow Perch at cellular, individual, and population levels.


Assuntos
Lagos/química , Nanopartículas Metálicas/toxicidade , Percas/metabolismo , Prata/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Catalase/metabolismo , Ecossistema , Metabolismo Energético/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Modelos Teóricos , Estresse Oxidativo/efeitos dos fármacos , Percas/crescimento & desenvolvimento
20.
Science ; 368(6487): 173-177, 2020 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-32273465

RESUMO

Two-dimensional systems can host exotic particles called anyons whose quantum statistics are neither bosonic nor fermionic. For example, the elementary excitations of the fractional quantum Hall effect at filling factor ν = 1/m (where m is an odd integer) have been predicted to obey Abelian fractional statistics, with a phase ϕ associated with the exchange of two particles equal to π/m However, despite numerous experimental attempts, clear signatures of fractional statistics have remained elusive. We experimentally demonstrate Abelian fractional statistics at filling factor ν = ⅓ by measuring the current correlations resulting from the collision between anyons at a beamsplitter. By analyzing their dependence on the anyon current impinging on the splitter and comparing with recent theoretical models, we extract ϕ = π/3, in agreement with predictions.

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