Search

The following cases demonstrate a proof of concept for the safe and effective use of the glucagon‐like‐peptide‐1 receptor agonist (GLP‐1 RA) semaglutide for weight loss in obese, non‐diabetic, end stage kidney disease (ESKD) patients on haemodialysis (HD), who are unable to undergo renal transplantation due to obesity. Obesity is a common barrier to wait‐listing for renal transplantation with effective, broadly applicable weight loss strategies lacking. GLP‐1 RAs have been shown to be effective adjuncts to achieve weight loss in non‐diabetic obese people. However, the major clinical trials excluded patients with ESKD on dialysis. This paper outlines the successful use of semaglutide to achieve a target body mass index (BMI) prior to renal transplant wait‐listing in two obese, non‐diabetic, HD patients. These patients achieved a 16% and 12.6% weight loss in under 9 months with one now waitlisted and the other transplanted. This strategy has the potential for broader use in this patient cohort to improve wait‐list times by overcoming this common barrier to renal transplantation. [ABSTRACT FROM AUTHOR]

Summary: Coral reefs are highly productive ecosystems with distinct biogeochemistry and biology nestled within unproductive oligotrophic gyres. Coral reef islands have often been associated with a nearshore enhancement in phytoplankton, a phenomenon known as the Island Mass Effect (IME). Despite being documented more than 60 years ago, much remains unknown about the extent and drivers of IMEs. Here we utilized 16S rRNA gene metabarcoding as a biological tracer to elucidate horizontal and vertical influence of an IME around the islands of Mo′orea and Tahiti, French Polynesia. We show that those nearshore oceanic stations with elevated chlorophyll a included bacterioplankton found in high abundance in the reef environment, suggesting advection of reef water is the source of altered nearshore biogeochemistry. We also observed communities in the nearshore deep chlorophyll maximum (DCM) with enhanced abundances of upper euphotic bacterioplankton that correlated with intrusions of low‐density, O2 rich water, suggesting island influence extends into the DCM. [ABSTRACT FROM AUTHOR]

Reef‐building corals form nutritional symbioses with endosymbiotic dinoflagellates (Symbiodiniaceae), a relationship that facilitates the ecological success of coral reefs. These symbionts are mostly acquired anew each generation from the environment during early life stages ("horizontal transmission"). Symbiodiniaceae species exhibit trait variation that directly impacts the health and performance of the coral host under ocean warming. Here, we test the capacity for larvae of a horizontally transmitting coral, Acropora tenuis, to establish symbioses with Symbiodiniaceae species in four genera that have varying thermal thresholds (the common symbiont genera, Cladocopium and Durusdinium, and the less common Fugacium and Gerakladium). Over a 2‐week period in January 2018, a series of both no‐choice and four‐way choice experiments were conducted at three temperatures (27, 30, and 31°C). Symbiont acquisition success and cell proliferation were measured in individual larvae. Larvae successfully acquired and maintained symbionts of all four genera in no‐choice experiments, and >80% of larvae were infected with at least three genera when offered a four‐way choice. Unexpectedly, Gerakladium symbionts increased in dominance over time, and at high temperatures outcompeted Durusdinium, which is regarded as thermally tolerant. Although Fugacium displayed the highest thermal tolerance in culture and reached similar cell densities to the other three symbionts at 31°C, it remained a background symbiont in choice experiments, suggesting host preference for other symbiont species. Larval survivorship at 1 week was highest in larvae associated with Gerakladium and Fugacium symbionts at 27 and 30°C, however at 31°C, mortality was similar for all treatments. We hypothesize that symbionts that are currently rare in corals (e.g., Gerakladium) may become more common and widespread in early life stages under climate warming. Uptake of such symbionts may function as a survival strategy in the wild, and has implications for reef restoration practices that use sexually produced coral stock. [ABSTRACT FROM AUTHOR]

Introduction: Hemodialysis (HD) with medium cut‐off (MCO) dialyzers may expand molecular clearance, predominantly larger middle molecules (molecular weight 25–60 kDa). However, the impact of MCO dialyzers on long‐term clearance of various other components of the uremic milieu is unknown. The tRial Evaluating Mid cut‐Off Value membrane clearance of Albumin and Light chains in HemoDialysis patients (REMOVAL‐HD) provided an opportunity to assess the effect of MCO dialyzers on protein‐bound uremic toxins and novel markers of mineral metabolism. Methods: This exploratory sub‐study of REMOVAL‐HD evaluated changes in protein‐bound solutes (total and free indoxyl sulfate [IS] and p‐cresyl sulfate [PCS]) and mineral metabolism markers (intact fibroblast growth factor‐23 [iFGF23], fetuin‐A and endogenous calciprotein particles [CPP‐1 and CPP‐2]). Mid‐week, pre‐HD serum samples were collected at baseline and after 12 and 24 weeks of MCO use in stable adult patients. Change from baseline to Week 12 and 24 was estimated using linear mixed effects models. Findings: Eighty‐nine participants were studied (mean age 67 ± 15 years, 38% female, 51% diabetic, median urine output 200 ml/24 h). Serum iFGF23 was reduced at Week 12 compared to baseline (−26.8% [95%CI −39.7, −11.1], p = 0.001), which was sustained at Week 24 (−21.7% [95%CI ‐35.7, −4.5], p = 0.012). There was no significant change in serum IS, PCS, fetuin‐A, CPP‐1, or CPP‐2. Discussion: The use of a MCO dialyzer over 24 weeks was associated with a sustained reduction in FGF23, while other measured components of the uremic milieu were not significantly altered. Further studies are required to determine whether FGF23 reduction is associated with improved patient outcomes. [ABSTRACT FROM AUTHOR]

Ocean warming is causing global coral bleaching events to increase in frequency, resulting in widespread coral mortality and disrupting the function of coral reef ecosystems. However, even during mass bleaching events, many corals resist bleaching despite exposure to abnormally high temperatures. While the physiological effects of bleaching have been well documented, the consequences of heat stress for bleaching‐resistant individuals are not well understood. In addition, much remains to be learned about how heat stress affects cellular‐level processes that may be overlooked at the organismal level, yet are crucial for coral performance in the short term and ecological success over the long term. Here we compared the physiological and cellular responses of bleaching‐resistant and bleaching‐susceptible corals throughout the 2019 marine heatwave in Hawai'i, a repeat bleaching event that occurred 4 years after the previous regional event. Relative bleaching susceptibility within species was consistent between the two bleaching events, yet corals of both resistant and susceptible phenotypes exhibited pronounced metabolic depression during the heatwave. At the cellular level, bleaching‐susceptible corals had lower intracellular pH than bleaching‐resistant corals at the peak of bleaching for both symbiont‐hosting and symbiont‐free cells, indicating greater disruption of acid–base homeostasis in bleaching‐susceptible individuals. Notably, cells from both phenotypes were unable to compensate for experimentally induced cellular acidosis, indicating that acid–base regulation was significantly impaired at the cellular level even in bleaching‐resistant corals and in cells containing symbionts. Thermal disturbances may thus have substantial ecological consequences, as even small reallocations in energy budgets to maintain homeostasis during stress can negatively affect fitness. These results suggest concern is warranted for corals coping with ocean acidification alongside ocean warming, as the feedback between temperature stress and acid–base regulation may further exacerbate the physiological effects of climate change. [ABSTRACT FROM AUTHOR]

The effects of nutrient pollution on coral reef ecosystems are multifaceted. Numerous experiments have sought to identify the physiological effects of nutrient enrichment on reef‐building corals, but the results have been variable and sensitive to choices of nutrient quantity, chemical composition and exposure duration.To test the effects of chronic, ecologically relevant nutrient enrichment on coral growth and photophysiology, we conducted a 5‐week continuous dosing experiment on two Hawaiian coral species, Porites compressa and Pocillopora acuta. We acclimated coral fragments to five nutrient concentrations (0.1–7 µM NO3‐ and 0.06–2.24 µM PO43‐) with constant stoichiometry 2.5:1 nitrate to phosphate) bracketing in situ observations from reefs throughout the Pacific.Nutrient enrichment linearly increased photophysiological performance of both species within 3 weeks. The effect of nutrients on P. acuta photochemical efficiency increased through time while a consistent response in P. compressa indicated acclimation to elevated nutrients within 5 weeks. Endosymbiont densities and total chlorophyll concentrations also increased proportionally with nutrient enrichment in P. acuta, but not in P. compressa, revealing contrasting patterns of host–symbiont acclimatization.The two species also exhibited contrasting effects of nutrient enrichment on skeletal growth. Calcification was enhanced at low nutrient enrichment (1 µM NO3‐) in P. acuta, but comparable to the control at higher concentrations, whereas calcification was reduced in P. compressa (30%–35%) above 3 µM NO3‐.Stable isotope analysis revealed species‐specific nitrogen uptake dynamics in the coral–algal symbiosis. The endosymbionts of P. acuta exhibited increased nitrogen uptake (decreased δ15N) and incorporation (19%–31% decrease in C:N ratios) across treatments. In contrast, P. compressa endosymbionts maintained constant δ15N values and low levels of nitrogen incorporation (9%–11% decrease in C:N ratios). The inability of P. acuta to regulate endosymbiont nutrient uptake may indicate an emerging destabilization in the coral–algal symbiosis under nutrient enrichment that could compromise resistance to additional environmental stressors.Our results highlight species‐specific differences in the coral–algal symbiosis, which influence responses to chronic nutrient enrichment. These findings showcase how symbioses can vary among closely related taxa and underscore the importance of considering how life‐history traits modify species response to environmental change. A free Plain Language Summary can be found within the Supporting Information of this article. [ABSTRACT FROM AUTHOR]

Submarine groundwater discharge (SGD) is an important transporter of solutes and fresh water in coastal systems worldwide. In high island systems with a mixed semidiurnal tidal cycle driving SGD, coastal biogeochemistry is temporally and spatially variable. Past studies have shown that SGD covaries with the local species composition, diversity, and richness of biological communities on a scale of meters. Empirical orthogonal function analyses (EOF)—a method analogous to principal components analysis which finds spatial patterns of variability and their time variation period—were used to define both the spatial and temporal variation in SGD using spatially resolved time series of salinity. The first two EOFs represented variability at the tidal 12‐h period and the daily 24‐h period, respectively, and were responsible for more than 50% of the SGD‐derived salinity variability. We used the first two EOFs to explore spatiotemporally explicit patterns in SGD variability and their relationships with benthic community structure in reef systems. Distance‐based linear models found significant relationships between multivariate community structure and variability in SGD at different periods. Taxa‐specific logistic regressions showed that zoanthids and turf are more likely to be present in areas with high tidally driven SGD variability, while the inverse relationship is true for the invasive rhodophyte Acanthophora spicifera, calcifying macroalgae, the native rhodophyte Pterocladiella sp., the cyanobacteria Lyngbya sp., and the invasive chlorophyte Avrainvillea amadelpha. These results show that benthic communities vary with respect to SGD derived salinity at the scale of hundreds of meters resulting in spatially heterogeneous biotic patches. [ABSTRACT FROM AUTHOR]

Summary: Factors that affect the respiration of organic carbon by marine bacteria can alter the extent to which the oceans act as a sink of atmospheric carbon dioxide. We designed seawater dilution experiments to assess the effect of pCO2 enrichment on heterotrophic bacterial community composition and metabolic potential in response to a pulse of phytoplankton‐derived organic carbon. Experiments included treatments of elevated (1000 p.p.m.) and low (250 p.p.m.) pCO2 amended with 10 μmol L−1 dissolved organic carbon from Emiliana huxleyi lysates, and were conducted using surface‐seawater collected from the South Pacific Subtropical Gyre. To assess differences in community composition and metabolic potential, shotgun metagenomic libraries were sequenced from low and elevated pCO2 treatments collected at the start of the experiment and following exponential growth. Our results indicate bacterial communities changed markedly in response to the organic matter pulse over time and were significantly affected by pCO2 enrichment. Elevated pCO2 also had disproportionate effects on the abundance of sequences related to proton pumps, carbohydrate metabolism, modifications of the phospholipid bilayer, resistance to toxic compounds and conjugative transfer. These results contribute to a growing understanding of the effects of elevated pCO2 on bacteria‐mediated carbon cycling during phytoplankton bloom conditions in the marine environment. [ABSTRACT FROM AUTHOR]

This paper examines the argument that scientific thinkers who embrace a religious tradition can promote intellectual integration between religion and science rather than fragmented discourse. It is argued that God's Word as an event and the concept of structural directedness, an organized movement toward a future that does not demand a consciously intended end, may be helpful in understanding God's actions in an indeterminant way. [ABSTRACT FROM AUTHOR]

Background: Secondary hyperparathyroidism (SHPT) in chronic kidney disease is associated with cardiovascular and bone pathology. Measures to achieve parathyroid hormone (PTH) target values and control biochemical abnormalities associated with SHPT require complex therapies, and severe SHPT often requires parathyroidectomy or the calcimimetic cinacalcet. In Australia, cinacalcet was publicly funded for dialysis patients from 2009 to 2015 when funding was withdrawn following publication of the EVOLVE study, which resulted in most patients on cinacalcet ceasing therapy. We examined the clinical and biochemical outcomes associated with this change at Australian renal centres. Aim: To assess changes to biochemical and clinical outcomes in dialysis patients following cessation of cinacalcet. Methods: We conducted a retrospective study of dialysis patients who ceased cinacalcet after August 2015 in 11 Australian units. Clinical outcomes and changes in biochemical parameters were assessed over a 24‐ and 12‐month period, respectively, from cessation of cinacalcet. Results: A total of 228 patients was included (17.7% of all dialysis patients from the units). Patients were aged 63 ± 15 years with 182 patients on haemodialysis and 46 on peritoneal dialysis. Over 24 months following cessation of cinacalcet, we observed 26 parathyroidectomies, 3 episodes of calciphylaxis, 8 fractures and 50 deaths. Eight patients recommenced cinacalcet, meeting criteria under a special access scheme. Biochemical changes from baseline to 12 months after cessation included increased levels of serum PTH from 54 (interquartile range 27–90) pmol/L to 85 (interquartile range 41–139) pmol/L (P < 0.0001), serum calcium from 2.3 ± 0.2 mmol/L to 2.5 ± 0.1 mmol/L (P < 0.0001) and alkaline phosphatase from 123 (92–176) IU/L to 143 (102–197) IU/L (P < 0.0001). Conclusion: Significant increases in serum PTH, calcium and alkaline phosphatase occurred over a 12‐month period following withdrawal of cinacalcet. Longer‐term follow up will determine if these biochemical and therapeutic changes are associated with altered rates of parathyroidectomies and cardiovascular mortality and morbidity. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the association between chronic subsyndromal symptoms of depression (SSD), cerebrospinal fluid (CSF) biomarkers, and neuropsychological performance in individuals with mild cognitive impairment (MCI).Methods: Participants included 238 older adults diagnosed with MCI from the Alzheimer's Disease Neuroimaging Initiative repository with cognitive and CSF amyloid beta (Aβ1-42 ), total tau (t-tau), and phosphorylated tau (p-tau) data. The Neuropsychiatric Inventory identified individuals with chronic endorsement (SSD group N = 80) or no endorsement (non-SSD group N = 158) of depressive symptoms across timepoints. CSF biomarker and cognitive performance were evaluated with linear regression models adjusting for age, education, gender, APOE genotype, global cognitive status, and SSD group.Results: As compared to the non-SSD group, the SSD group displayed lower CSF Aβ1-42 levels (β = -24.293, S.E. = 6.345, P < 0.001). No group differences were observed for CSF t-tau (P = 0.497) or p-tau levels (P = 0.392). Lower CSF Aβ1-42 levels were associated with poorer performance on learning (β = 0.041, S.E. = 0.018, P = 0.021) and memory (β = -0.012, S.E. = 0.005, P = 0.031) measures, whereas higher CSF t-tau levels were associated with poorer performance on measures of global cognition (β = 0.022, S.E = 0.008, P = 0.007) and language (β = -0.010, S.E = 0.004, P = 0.019). SSD was independently associated with diminished global cognition, learning and memory, language, and executive function performance over and above the effects of CSF biomarkers (all P < 0.05).Conclusions: MCI participants with SSD displayed diminished CSF Aβ1-42 levels but did not differ from non-SSD controls in CSF tau levels. Additionally, CSF biomarkers and SSD independently accounted for variance in cognitive performance, suggesting that these factors may uniquely confer cognitive risk in MCI. [ABSTRACT FROM AUTHOR]

Abstract: Dissolved organic matter (DOM) composition influences microbial community metabolism and benthic primary producers are a source of DOM in coral reefs. As reef benthic communities change, in part due to nutrient pollution, understanding impacts on reef microbial processes requires knowledge of DOM sources and composition. We conducted a multi‐week mesocosm experiment dosing four coral reef benthic constituents with three levels of nitrate and phosphate to contrast exudate composition and quantify the effects of nutrient enrichment on exudate release. Moderate nutrient enrichment enhanced bulk dissolved organic carbon exudation by all producers. Corals exuded rapidly accumulating DOM with a markedly high concentration of aromatic amino acid‐like fluorescent DOM components that clearly distinguishes them from algal exudates, which were dominated by humic‐like fluorescent components and did not accumulate significantly. Our results indicate that corals and algae release DOM of different quality and the quantity of DOM release increases with inorganic nutrient availability. [ABSTRACT FROM AUTHOR]

Summary: Primers targeting the 16S small subunit ribosomal RNA marker gene, used to characterize bacterial and archaeal communities, have recently been re‐evaluated for marine planktonic habitats. To investigate whether primer selection affects the ecological interpretation of bacterioplankton populations and community dynamics, amplicon sequencing with four primer sets targeting several hypervariable regions of the 16S rRNA gene was conducted on both mock communities constructed from cloned 16S rRNA genes and a time‐series of DNA samples from the temperate coastal Santa Barbara Channel. Ecological interpretations of community structure (delineation of depth and seasonality, correlations with environmental factors) were similar across primer sets, while population dynamics varied. We observed substantial differences in relative abundances of taxa known to be poorly resolved by some primer sets, such as Thaumarchaeota and SAR11, and unexpected taxa including Roseobacter clades. Though the magnitude of relative abundances of common OTUs differed between primer sets, the relative abundances of the OTUs were nonetheless strongly correlated. We do not endorse one primer set but rather enumerate strengths and weaknesses to facilitate selection appropriate to a system or experimental goal. While 16S rRNA gene primer bias suggests caution in assessing quantitative population dynamics, community dynamics appear robust across studies using different primers. [ABSTRACT FROM AUTHOR]

Abstract: Background: The international classification of diseases (ICD) code is frequently used to identify renal impairment in epidemiological research. However, Australian studies examining accuracy of this administrative data in coding kidney injury are lacking. Aims: To compare the ICD 10 coding with the kidney disease: improving global outcomes (KDIGO) criteria in diagnosing acute kidney injury (AKI) and/or chronic kidney disease (CKD). Methods: A retrospective study of 325 patients admitted to general medicine during January 2012 was performed. Sensitivity and specificity of ICD 10 in identifying AKI and CKD were calculated using KDIGO as gold standard. Results: The sensitivities of ICD 10 in identifying AKI and CKD were low for both (59.5% and 54.1%), but the specificities were high (86.2% and 90.2%). Using KDIGO criteria, we identified 72 AKI (22%), 56 CKD (17%), 64 AKI on CKD (19%) and 133 controls (40%). Compared to the control group, patients with AKI and AKI on CKD had longer length of stay (3.2 vs 4.9 days and 3.2 vs 4.8 days, P = 0.20). Renal impairment groups had increased in‐hospital mortality rate (5% control, 6% AKI, 10% CKD, 9% AKI on CKD) and re‐admission rate within 30 days (13% control, 20% AKI, 25% CKD, 26% AKI on CKD). After adjusting for age, gender and comorbidities, the difference in outcomes was not statistically significant. Conclusion: This study shows that ICD 10 fails to identify almost half of the patients with AKI (40.5%) and CKD (45.9%) in our cohort. A total of 60% had evidence of renal impairment as defined by KDIGO. [ABSTRACT FROM AUTHOR]

Microbial symbiotic partners, such as those associated with Scleractinian corals, mediate biochemical transformations that influence host performance and survival. While evidence suggests microbial community composition partly accounts for differences in coral physiology, how these symbionts affect metabolic pathways remains underexplored. We aimed to assess functional implications of variation among coral-associated microbial partners in hospite. To this end, we characterized and compared metabolomic profiles and microbial community composition from nine reef-building coral species. These data demonstrate metabolite profiles and microbial communities are species-specific and are correlated to one another. Using Porites spp. as a case study, we present evidence that the relative abundance of different sub-clades of Symbiodinium and bacterial/archaeal families are linked to positive and negative metabolomic signatures. Our data suggest that while some microbial partners benefit the union, others are more opportunistic with potential detriment to the host. Consequently, coral partner choice likely influences cellular metabolic activities and, therefore, holobiont nutrition. [ABSTRACT FROM AUTHOR]

We investigated the effects of a wildfire on stream physical, chemical and biological characteristics in a Mediterranean climate, comparing stream community structure and consumer resource use in burned versus unburned catchments in Santa Barbara County, CA, U.S.A., Canopy cover was lower and water temperature was higher in streams draining basins where the riparian vegetation burned than in streams in unburned basins or burned basins where riparian vegetation remained intact. Stream flow and suspended sediment concentrations during large post-fire storms and wet season nutrient levels were higher in burned than unburned catchments, with increased sedimentation after flood peaks., A year after fires, algal levels were highest in streams where riparian vegetation burned and lowest in streams in burned basins where the riparian canopy remained intact. In contrast, streams in burned basins had lower particulate organic matter, detritivore and predator levels than unburned basins, regardless of whether riparian vegetation burned. Where present, southern California steelhead trout ( Oncorhynchus mykiss) were extirpated from burned basins., Algivore densities were high in streams with burned riparian vegetation for two post-fire years before declining to unburned stream levels. Shredder densities rebounded in streams in burned basins with intact riparian vegetation, but remained low for 4 years where riparian vegetation burned. Predatory invertebrate densities increased at sites where trout were eliminated by wildfire., Hydrogen stable isotope analysis indicated that the diets of most invertebrate taxa in streams with burned riparian vegetation a year after fires were comprised of a higher proportion of algal material than riparian detritus relative to invertebrates in streams with intact riparian vegetation., Wildfire impacts on stream food webs are determined, in part, by fire severity in the riparian zone. Streams with burned riparian canopies supported algal-based food webs and streams with intact riparian canopies sustained detrital-based food webs. Fire affected basal resources (nutrients, light, allochthonous inputs) with bottom-up effects on primary producers and consumers, but top-down effects were decoupled at the trophic link between invertebrate predators and primary consumers. [ABSTRACT FROM AUTHOR]

Understanding bacterioplankton community dynamics in coastal hypoxic environments is relevant to global biogeochemistry because coastal hypoxia is increasing worldwide. The temporal dynamics of bacterioplankton communities were analysed throughout the illuminated water column of Devil's Hole, Bermuda during the 6-week annual transition from a strongly stratified water column with suboxic and high- pCO2 bottom waters to a fully mixed and ventilated state during 2008. A suite of culture-independent methods provided a quantitative spatiotemporal characterization of bacterioplankton community changes, including both direct counts and rRNA gene sequencing. During stratification, the surface waters were dominated by the SAR11 clade of A lphaproteobacteria and the cyanobacterium S ynechococcus. In the suboxic bottom waters, cells from the order C hlorobiales prevailed, with gene sequences indicating members of the genera C hlorobium and P rosthecochloris - anoxygenic photoautotrophs that utilize sulfide as a source of electrons for photosynthesis. Transitional zones of hypoxia also exhibited elevated levels of methane- and sulfur-oxidizing bacteria relative to the overlying waters. The abundance of both T haumarcheota and E uryarcheota were elevated in the suboxic bottom waters (> 109 cells l−1). Following convective mixing, the entire water column returned to a community typical of oxygenated waters, with E uryarcheota only averaging 5% of cells, and C hlorobiales and T haumarcheota absent. [ABSTRACT FROM AUTHOR]

Interactions between dissolved organic carbon (DOC) and bacterioplankton were examined during a diatom and Phaeocystis bloom in the Santa Barbara Channel (SBC) over five days following an upwelling event. The SBC was heterogeneous in physical state (recently upwelled vs. more stratified), nutrient concentration, and productivity, encompassing phytoplankton physiological states from a healthy bloom through the onset of silicon stress. DOC accumulated in the upper 10 m over the bloom, with compositional shifts indicated by chromophoric dissolved organic matter (CDOM) parameters. DOC bioavailability and bacterial growth and community composition responses were assessed with dilution batch-culture bioassays. In these experiments, bacterioplankton DOC usage increased over the bloom, with uptake of 1.5-5.3 μmol L−1 over three days, 1.5-5.7 μmol L−1 over one week, and 1.8-10.8 μmol L−1 over 10 weeks. DOC removal was poorly correlated with traditional proxies of bioavailability (chlorophyll a concentration, elemental ratios of dissolved organic matter, and CDOM). However, bacterial growth efficiency (BGE) was strongly related to in situ conditions, with higher BGEs on fresher, late-bloom DOC. After 10 weeks, 1.6-15.7 μmol L−1 of the DOC that accumulated during the bloom remained unutilized in the bioassays, with higher concentrations of persistent DOC in experiments from senescent bloom physiological states, supporting the putative relationship between phytoplankton blooms and seasonal DOC accumulation in the field. These experiments demonstrate that DOC released by the plankton community during a bloom fuels increased short-term and long-term bacterial activity, enhances presumed trophic transfer via increased BGEs, and leads to the accumulation of persistent, potentially exportable, DOC. © 2015 Association for the Sciences of Limnology and Oceanography [ABSTRACT FROM AUTHOR]

Eddies are mesoscale oceanographic features (∼ 200 km diameter) that can cause transient blooms of phytoplankton by shifting density isoclines in relation to light and nutrient resources. To better understand how bacterioplankton respond to eddies, we examined depth-resolved distributions of bacterial populations across an anticyclonic mode-water eddy in the Sargasso Sea. Previous work on this eddy has documented elevated phytoplankton productivity and diatom abundance within the eddy centre with coincident bacterial productivity and biomass maxima. We illustrate bacterial community shifts within the eddy centre, differentiating populations uplifted along isopycnals from those enriched or depleted at horizons of enhanced bacterial and primary productivity. Phylotypes belonging to the Roseobacter, OCS116 and marine Actinobacteria clades were enriched in the eddy core and were highly correlated with pigment-based indicators of diatom abundance, supporting developing hypotheses that members of these clades associate with phytoplankton blooms. Typical mesopelagic clades ( SAR202, SAR324, SAR406 and SAR11 IIb) were uplifted within the eddy centre, increasing bacterial diversity in the lower euphotic zone. Typical surface oligotrophic clades ( SAR116, OM75, Prochlorococcus and SAR11 Ia) were relatively depleted in the eddy centre. The biogeochemical context of a bloom-inducing eddy provides insight into the ecology of the diverse uncultured bacterioplankton dominating the oligotrophic oceans. [ABSTRACT FROM AUTHOR]

The article focuses on the seven steps in the design, presentation, and analysis of Scholarship of Teaching and Learning (SOTL). The steps include recognition and care on a problem, search for effective solutions and existing hypothesis, and qualitative and narrative explorations of problem. Steps on making a learning design, conducting qualitative and quantitative assessments of the learning designs' effects, and making the design public are also discussed.

Eutrophication remains one of the foremost impacts of industrialization and population expansion on aquatic ecosystems worldwide. Selecting metrics for assessing the manner in which communities and biogeochemical processes respond to nutrient fertilization is an ongoing management challenge critical both for detecting changes and for monitoring recovery of impaired environments. A key limitation to the selection of response variables is the lack of consistent evaluation of metrics under the same conditions in multiple systems across ecoregions. Here we report the results of nutrient‐diffusing agar fertilization experiments conducted simultaneously in 30 streams in two distinct ecoregions of California, USA: the mountainous Sierra Nevada and the coastal chaparral of Santa Barbara county. In each experiment we evaluated algal community shifts across five nutrient delivery rates using multiple response variables at the ecosystem process (respiration and primary production), community (biomass and diversity metrics), functional group (nitrogen fixing, growth form, nutrient adaptation), and taxonomic group (indicator species, genera, families) levels of ecological organization. We used mixed‐effect general linear models to quantify the magnitude, sensitivity, and consistency of responses among streams within and across ecoregions to provide an objective assessment of the potential for each variable to describe and detect significant changes in algal community characteristics. Our results indicate that ecosystem‐ and community‐level variables showed significant and consistent nutrient responses among diverse streams and across the two ecoregions, while indicator taxa and functional groups were less likely to respond consistently to nutrient enrichment. We discuss the relevance of our findings to the ongoing development of monitoring and bioassessment strategies for aquatic eutrophication. [ABSTRACT FROM AUTHOR]

We analyzed the role of Stat3, Ascl1a, and Lin28a in Müller glia reentry into the cell cycle following damage to the zebrafish retina. Immunohistochemical analysis was employed to determine the temporal and spatial expression of Stat3 and Ascl1a proteins following rod and cone photoreceptor cell apoptosis. Stat3 expression was observed in all Müller glia, whereas Ascl1a expression was restricted to only the mitotic Müller glia. Knockdown of Stat3 protein expression did not affect photoreceptor apoptosis, but significantly reduced, without abolishing, the number of proliferating Ascl1a-positive Müller glia. Knockdown of Ascl1a protein also did not change the extent of photoreceptor apoptosis, but did yield significantly fewer Müller glia that reentered the cell cycle relative to the stat3 morphant and significantly decreased the number and intensity of Stat3-expressing Müller glia. Finally, introduction of lin28a morpholinos resulted in decreased Müller glia expression of Stat3 and Ascl1a, significantly reducing the number of proliferating Müller glia. Thus, there are three populations of Müller glia in the light-damaged zebrafish retina: 1) Stat3-expressing Ascl1a-nonexpressing nonproliferating (quiescent) Müller glia; 2) Stat3-dependent Ascl1a-dependent proliferating Müller glia; and 3) Stat3-independent Ascl1a-dependent proliferating Müller glia. Whereas Ascl1a and Lin28a are required for Müller glia proliferation, Stat3 is necessary for the maximal number of Müller glia to proliferate during regeneration of the damaged zebrafish retina. J. Comp. Neurol. 520:4294-4311, 2012. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Bacterioplankton are the primary trophic conduit for dissolved organic carbon (DOC) and linking community structure with DOC utilization is central to understanding global carbon cycling. We coupled stable isotope probing (SIP) with 16S rRNA pyrosequencing in dark seawater culture experiments on euphotic and mesopelagic communities from the Sargasso Sea. Parallel cultures were amended with equimolar quantities of four DO13C substrates to simultaneously evaluate community utilization and population-specific incorporation. Of the substrates tested - two cyanobacterial products (exudates or lysates from a culture of Synechococcus) and two defined monosaccharides (glucose or gluconic acid) - the cyanobacterial exudates were incorporated by the greatest diversity of oligotrophic bacterioplankton populations in surface waters, including taxa from > 10 major subclades within the Flavobacteria, Actinobacteria, Verrucomicrobia and Proteobacteria (including SAR11). In contrast, the monosaccharide glucose was not incorporated by any taxa belonging to extant oligotrophic oceanic clades. Conversely, proteobacterial copiotrophs, which were rare in the ambient water (< 0.1% of sequences), grew rapidly on all DOC amendments at both depths, but with different substrate preferences among lineages. We present a new analytical framework for using SIP to detect DOC incorporation across diverse oligotrophic bacterioplankton and discuss implications for the ecology of bacterial-DOC interactions among populations of diverging trophic strategies. [ABSTRACT FROM AUTHOR]

The understanding of biogeochemical cycles has benefited from technological advances facilitating new kinds of measurements and observations. Satellite-borne ocean-color sensors that assess the physiological status of phytoplankton have led to improved estimates of oceanic productivity, as have micrometeorological approaches measuring terrestrial photosynthesis and respiration. The advent of satellites fitted with synthetic aperture radar (a specialized sensor used to determine inundation extent and vegetation types in wetlands) has revealed large fluxes of carbon dioxide and methane from these areas. Advances in the measurement of chemical constituents and turbulence have allowed the detection of high-resolution coupling between physical and biogeochemical processes. Genomics and proteomics - the study of genes and of an organism's complement of proteins, respectively - have revolutionized our understanding of the types of cells present in the environment and their ability to transform elements by allowing direct assessment of gene and protein sequences. [ABSTRACT FROM AUTHOR]

The idea that productivity regulates species diversity is deeply ingrained in the field of ecology. Yet, over the past few decades, an increasing number of experiments have shown that species diversity controls, rather than simply responds to, biomass production. These contrasting perspectives have led to a seeming paradox: Is diversity the cause or the consequence of biological production? Here we present empirical evidence for the multivariate productivity--diversity (MPD) hypothesis, which argues that differing perspectives on productivity--diversity relationships can be resolved by recognizing that historical research has focused on how resource supply regulates both the productivity and richness of local competitors, whereas more recent studies have focused on how the richness of a colonist pool regulates the efficiency by which resources are captured and converted into new tissue. The MPD hypothesis predicts that three pathways operate concurrently to generate productivity--diversity relationships in nature: (1) resource supply directly limits the standing biomass and/or rate of new production by primary producers, (2) producer biomass is directly influenced by the richness of species that locally compete for resources, and (3) resource supply rate indirectly affects producer biomass by influencing the fraction of species from a colonist pool that locally coexist. To examine whether this set of pathways explains covariation between productivity and diversity in natural streams, we used nutrient-diffusing agar "patches" to manipulate resource supply rates in 20 streams throughout the Sierra Nevada mountain range, California, USA. We then measured the fraction of periphyton species from the stream colonist pool co-occurring on each nutrient patch, as well as the standing biomass and rates of primary production. Natural patterns of covariation agreed with predictions of the MPD hypothesis. Algal biomass was an increasing function of nutrient supply, and an increasing function of local richness. The fraction of species from the colonist pool found co- occurring on a patch was a concave-down function of nutrient supply, causing nutrients to indirectly affect biomass via control over local richness. These results suggest that the MPD hypothesis is a viable explanation of patterns of diversity and productivity in natural stream ecosystems, and that it has potential to merge the historical view that productivity drives diversity with a parallel view that diversity drives productivity. [ABSTRACT FROM AUTHOR]

The Tucson Police Department, Tucson, AZ, has begun using the Polyshok Impact Reactive Projectile (IRP), a new type of shotgun ammunition that includes a lead bead core that travels within single, plastic-encased projectile. On impact, the core is released to distribute over a small area, thereby disintegrating on impact to reduce the likelihood of exit or collateral damage on missed shots. After a brief review of shotgun slug ballistics and wound characteristics and a discussion of the mechanism of the Polyshok IRP, we report the first death in the United States from this ammunition. Findings included a single entrance wound with plastic ammunition components and small lead particles recovered from the body, the combination of which normally would suggest a close-range shooting with birdshot. However, the characteristics of this ammunition create different patterns than are found with slugs or shot, so that a medical examiner unfamiliar with the Polyshok IRP could draw inaccurate conclusions about ammunition and range of fire. Because the single projectile fired from this ammunition is composed of both plastic and lead, plastic components are likely to be found within the wound at any range of fire, unlike traditional shot or slug ammunition. Also, the small size of lead particles found spread through the wound cavity would ordinarily suggest a small-size shot, whereas the external appearance of the wound (a single entrance with no dispersion of shot) and the pattern of tissue destruction are more consistent with the patterns of injury associated with shotgun slugs. [ABSTRACT FROM AUTHOR]

The article presents information on a study examining the relationships between students' attitude and achievement. It concluded that students' attitudes toward the subjects they study influence their performance in those subjects. Researchers have demonstrated that students' attitudes about math ability and about a particular course did not predict achievement in college-level physical chemistry. The literature on the relationship between attitude and achievement have suggested that attitude does not predict achievement or explains only modest amounts of variation in achievement. The study further investigated the relationship between acceptance of evolution and achievement. It focused on three main questions including, whether students accept evolution as science, whether instruction influence students' acceptance of evolution and whether students' achievement related to their acceptance of evolution in an evolution course. Results found that a substantial majority of students accepted evolution and rejected most claims of creationism. They are more positive toward the individual tenets of evolution than to the general statement of evolution.

SUMMARY: The kidney may be involved in several forms of systemic vasculitis, particularly those affecting small-calibre blood vessels. Hence, the majority of cases involve patients with Wegener's granulomatosis, Churg–Strauss syndrome or microscopic polyangiitis. Anti-neutrophil cytoplasmic antibodies (ANCA) are found in the majority of these patients and their detection has increased the sensitivity and specificity of diagnosis. However, the role of ANCA in the pathogenesis of these lesions remains uncertain. Moreover, the approach to treatment, both in terms of induction and maintenance of remission, remains problematic. This brief review discusses aspects of ANCA and current approaches to management. [ABSTRACT FROM AUTHOR]

Discusses the link between group learning and critical thinking. Theoretical and empirical approaches to critical thinking; Effect of preconceptual thinking on critical thinking; Discourse communities as inhibiting critical thinking; Collaborative learning and critical thinking; Intellectual development and collaborative learning.

A series of experiments was conducted to investigate sex, housing conditions, and strain as possible factors influencing the interference effect of prior exposure to shock on shock-induced aggression. In albino subjects, female rats and rats housed in community cages evidenced the greatest suppression in aggression following prior exposure to shock. In addition, ten sessions of prior exposure to shock produced a greater suppression in shock-induced fighting than 20 sessions of prior exposure to shock. The prior shock effect was not obtained with hooded subjects. Responsivity to shock was also investigated to determine whether the prior exposure to shock attenuation of shock-induced fighting was a consequence of reduced activity in response to shock. Responsivity to shock measured with an isometric platform accounted for, less than 4% of the variance in shock-induced fighting in the single experiment that obtained a correlation between responsivity and shock-induced aggression. [ABSTRACT FROM AUTHOR]

We examined bacterioplankton community composition (BCC; using polymerase chain reaction-based phylogenetic fingerprinting) and the composition of dissolved organic matter (DOM; using scanning fluorometry) within lake chains in high-elevation catchments of the Sierra Nevada, California. We compared temporal BCC dynamics in two connected cirque lakes and their inlets and found that lake : inlet community similarity of both lakes declined with increasing residence time because of seasonal snowpack melting. However, for over 3 yr the headwater lake remained distinct from its inlet even during peak snowmelt (residence time <5 d), whereas the downstream lake was consistently similar to both its inlet and the upstream lake. We subsequently sampled 17 lake chains (4-8 lakes each) throughout the Sierra Nevada longitudinally to examine how landscape position and catchment characteristics influenced the similarity in BCC and DOM among lakes and their connecting streams. Headwater lakes were significantly less similar to their inlet streams than were downstream lakes. BCC was heterogeneous throughout each catchment, but headwater inlet BCC was consistently distinct from all downstream samples. In contrast, DOM exhibited a trend of increasing homogeneity as water moved downstream: upstream and downstream waters were distinct but without clear headwater outliers. The similarity in BCC and DOM between any two lakes within a chain declined with geographic distance. Our results illustrate the contrasting roles of environmental selection and dispersal in structuring bacterioplankton communities, supporting both strong within-lake environmental selection for communities distinct from terrigenous inputs and a weaker effect of geographic dispersal differentiating communities among lakes linked by advective flow. [ABSTRACT FROM AUTHOR]