Evaluation of macrophyte control in 38 Florida lakes using triploid grass carp

Florida’s large number of shallow lakes, warm climate and long growing season have contributed to the development of excessive growths of aquatic macrophytes that have seriously interfered with many water use activities. The introduction of exotic aquatic macrophyte species such as hydrilla ( Hydrilla verticillata ) have added significantly to aquatic plant problems in Florida lakes. The use of grass carp ( Ctenopharyngodon idella ) can be an effective and economical control for aquatic vegetation such as hydrilla. Early stocking rates (24 to 74 grass carp per hectare of lake area) resulted in grass carp consumption rates that vastly exceeded the growth rates of the aquatic plants and often resulted in the total loss of all submersed vegetation. This study looked at 38 Florida lakes that had been stocked with grass carp for 3 to 10 years with stocking rates ranging from < 1 to 59 grass carp per hectare of lake and 1 to 207 grass carp per hectare of vegetation to determine the long term effects of grass carp on aquatic macrophyte communities. The median PAC (percent area coverage) value of aquatic macrophytes for the study lakes after they were stocked with grass carp was 14% and the median PVI (percent volume infested) value of aquatic macrophytes was 2%. Only lakes stocked with less than 25 to 30 fish per hectare of vegetation tended to have higher than median PAC and PVI values. When grass carp are stocked at levels of > 25 to 30 fish per hectare of vegetation the complete control of aquatic vegetation can be achieved, with the exception of a few species of plants that grass carp have extreme difficulty consuming. If the management goal for a lake is to control some of the problem aquatic plants while maintaining a small population of predominately unpalatable aquatic plants, grass carp can be stocked at approximately 25 to 30 fish per hectare of vegetation

Effects of pH and specific conductance confound the use of the Florida Lake Vegetation Index to identify anthropogenic eutrophication

We found that the Florida Lake Vegetation Index (LVI) did not identify Florida lakes that were impaired due to excess loading of phosphorus or nitrogen from anthropogenic sources. The index is based on 4 plant metrics: the Coefficient of Conservatism of the dominant or co-dominant taxa, the percent of sensitive taxa, the percent of native taxa, and the percent of invasive exotic taxa. Our analysis of the data used by the Florida Department of Environmental Protection to establish and calibrate this biotic index found no link between nutrient concentrations and the LVI. The LVI was primarily associated with the pH and specific conductance of the lake waters, with the best scores found in acidic lakes and the poorest scores in more alkaline lakes. These variables are the result of natural gradients, not pollution, and are not included in the calculation of the LVI. Our study illustrates the importance of considering natural factors that determine the value of any index of biological integrity before it is used to indicate anthropogenic pollution

Monitoring by citizen scientists demonstrates water clarity of Maine (USA) lakes is stable, not declining, due to cultural eutrophication

Using data collected with 3 different methods, we found no decreases in the average water clarity of Maine (USA) lakes over different periods of time. Field measurements of Secchi disk depths in the summer months by volunteer samplers in several hundred lakes showed a small, statistically significant increase in water transparency during the period 1976 through 2013. A reanalysis of satellite-inferred Secchi depths between 1990 and 2010 showed no trend over time. In addition, diatom-inferred Secchi depths from short sediment cores in a randomly selected group of Maine lakes analyzed by the US Environmental Protection Agency showed no statistically significant difference between the average Secchi depths in a pre-1850 time period and the early 1990s. Lake maximum depth was the most important morphological variable associated with water clarity among Maine lakes. In individual lakes, both water color and chlorophyll were inversely correlated with Secchi disk depths. The statewide annual average Secchi depths for the summer months were inversely correlated with water color and the amount of precipitation for the months of January through June. Drought years led to increased Secchi depths

Puntos de inflexión en los gradientes de composición de las comunidades de plantas acuáticas de diferentes continentes

Unravelling patterns and mechanisms of biogeographical transitions is crucial if we are to understand compositional gradients at large spatial extents, but no studies have thus far examined breakpoints in community composition of freshwater plants across continents. Using a dataset of almost 500 observations of lake plant community composition from six continents, we examined, for the first time, if such breakpoints in geographical space exist for freshwater plants and how well a suite of ecological factors (including climatic and local environmental variables) can explain transitions in community composition from the subtropics to the poles. Our combination of multivariate regression tree (MRT) analysis and k-means partitioning suggests that the most abrupt breakpoint exists between temperate to boreal regions on the one hand and freshwater plant communities harbouring mainly subtropical or Mediterranean assemblages on the other. The spatially structured variation in current climatic conditions is the most likely candidate for controlling these latitudinal patterns, although one cannot rule out joint effects of eco-evolutionary constraints in the harsher high-latitude environments and post-glacial migration lags after Pleistocene Ice Ages. Overall, our study supports the foundations of global regionalisation for freshwater plants and anticipates further biogeographical research on freshwater plant communities once datasets have been harmonised for conducting large-scale spatial analyses.publishedVersio

Concurrent Oral 1 - Therapy of rheumatic disease: OP4. Effectiveness of Rituximab in Rheumatoid Arthritis: Results from the British Society for Rheumatology Biologics Register (BSRBR)

Background: Rituximab (RTX) in combination with methotrexate (MTX) has been licensed since 2006 for the management of severe active rheumatoid arthritis (RA) in patients who have failed at least one anti-tumour necrosis factor (anti-TNF) therapy. Published clinical trials have demonstrated the efficacy of RTX in improving both clinical symptoms and patients' physical function. This study aimed to assess the effectiveness of RTX in RA patients treated in routine clinical practice by examining clinical and patient reported outcomes six months after receiving a first course of RTX. Methods: The analysis involved 550 RA patients registered with the BSRBR, who were starting RTX and were followed up for at least 6 months. Change in Disease Activity Score (DAS28) and European League Against Rheumatism (EULAR) response were used to assess the clinical response while change in Health Assessment Questionnaire (HAQ) score was used to assess the physical function of the patients 6 months after starting RTX. The change in DAS28 and HAQ was compared between seronegative and seropositive patients and anti-TNF naïve patients versus anti-TNF failures. The response was also compared between patients receiving RTX in combination with MTX, other non-biologic disease modifying anti-rheumatic drugs (nbDMARDs) or no nbDMARDs. Results: The mean (s.d.) age of the cohort was 59 (12) years and 78% of the patients were females. The patients had a mean (s.d.) of 15 (10) years of disease duration. 16% were biologic naïve while 84% were anti-TNF failures. 32% of the patients were seronegative and 68% were seropositive. The mean (95% CI) DAS28 at baseline was 6.2 (6.1, 6.3) which decreased to 4.8 (4.7, 4.9) at 6 months of follow up. 16% were EULAR good responders, 43% were moderate responders and 41% were non responders. The mean (95% CI) change in HAQ was −0.1 (−0.2, −0.1) (Table 1). The mean change in DAS28 was similar in seropositive and seronegative patients (p = 0.18) while the anti-TNF naïve patients showed a greater reduction in DAS28 scores than anti-TNF failures (p = 0.05). Patients receiving RTX in combination with MTX showed similar changes in DAS28 and HAQ compared to patients receiving RTX alone or with other nbDMARDs. Conclusions: RTX has proven to be effective in the routine clinical practice. Anti-TNF naïve patients seem to benefit more from RTX treatment than anti-TNF failures. Disclosure statement: The authors have declared no conflicts of interes

Deciphering the Structure, Growth and Assembly of Amyloid-Like Fibrils Using High-Speed Atomic Force Microscopy

Formation of fibrillar structures of proteins that deposit into aggregates has been suggested to play a key role in various neurodegenerative diseases. However mechanisms and dynamics of fibrillization remains to be elucidated. We have previously established that lithostathine, a protein overexpressed in the pre-clinical stages of Alzheimer's disease and present in the pathognomonic lesions associated with this disease, form fibrillar aggregates after its N-terminal truncation. In this paper we visualized, using high-speed atomic force microscopy (HS-AFM), growth and assembly of lithostathine protofibrils under physiological conditions with a time resolution of one image/s. Real-time imaging highlighted a very high velocity of elongation. Formation of fibrils via protofibril lateral association and stacking was also monitored revealing a zipper-like mechanism of association. We also demonstrate that, like other amyloid ß peptides, two lithostathine protofibrils can associate to form helical fibrils. Another striking finding is the propensity of the end of a growing protofibril or fibril to associate with the edge of a second fibril, forming false branching point. Taken together this study provides new clues about fibrillization mechanism of amyloid proteins

Aggression, anxiety and vocalizations in animals: GABA A and 5-HT anxiolytics

A continuing challenge for preclinical research on anxiolytic drugs is to capture the affective dimension that characterizes anxiety and aggression, either in their adaptive forms or when they become of clinical concern. Experimental protocols for the preclinical study of anxiolytic drugs typically involve the suppression of conditioned or unconditioned social and exploratory behavior (e.g., punished drinking or social interactions) and demonstrate the reversal of this behavioral suppression by drugs acting on the benzodiazepine-GABA A complex. Less frequently, aversive events engender increases in conditioned or unconditioned behavior that are reversed by anxiolytic drugs (e.g., fear-potentiated startle). More recently, putative anxiolytics which target 5-HT receptor subtypes produced effects in these traditional protocols that often are not systematic and robust. We propose ethological studies of vocal expressions in rodents and primates during social confrontations, separation from social companions, or exposure to aversive environmental events as promising sources of information on the affective features of behavior. This approach focusses on vocal and other display behavior with clear functional validity and homology. Drugs with anxiolytic effects that act on the benzodiazepine-GABA A receptor complex and on 5-HT 1A receptors systematically and potently alter specific vocalizations in rodents and primates in a pharmacologically reversible manner; the specificity of these effects on vocalizations is evident due to the effectiveness of low doses that do not compromise other physiological and behavioral processes. Antagonists at the benzodiazepine receptor reverse the effects of full agonists on vocalizations, particularly when these occur in threatening, startling and distressing contexts. With the development of antagonists at 5-HT receptor subtypes, it can be anticipated that similar receptor-specificity can be established for the effects of 5-HT anxiolytics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46351/1/213_2005_Article_BF02245590.pd

To which world regions does the valence–dominance model of social perception apply?

Over the past 10 years, Oosterhof and Todorov’s valence–dominance model has emerged as the most prominent account of how people evaluate faces on social dimensions. In this model, two dimensions (valence and dominance) underpin social judgements of faces. Because this model has primarily been developed and tested in Western regions, it is unclear whether these findings apply to other regions. We addressed this question by replicating Oosterhof and Todorov’s methodology across 11 world regions, 41 countries and 11,570 participants. When we used Oosterhof and Todorov’s original analysis strategy, the valence–dominance model generalized across regions. When we used an alternative methodology to allow for correlated dimensions, we observed much less generalization. Collectively, these results suggest that, while the valence–dominance model generalizes very well across regions when dimensions are forced to be orthogonal, regional differences are revealed when we use different extraction methods and correlate and rotate the dimension reduction solution.C.L. was supported by the Vienna Science and Technology Fund (WWTF VRG13-007); L.M.D. was supported by ERC 647910 (KINSHIP); D.I.B. and N.I. received funding from CONICET, Argentina; L.K., F.K. and Á. Putz were supported by the European Social Fund (EFOP-3.6.1.-16-2016-00004; ‘Comprehensive Development for Implementing Smart Specialization Strategies at the University of Pécs’). K.U. and E. Vergauwe were supported by a grant from the Swiss National Science Foundation (PZ00P1_154911 to E. Vergauwe). T.G. is supported by the Social Sciences and Humanities Research Council of Canada (SSHRC). M.A.V. was supported by grants 2016-T1/SOC-1395 (Comunidad de Madrid) and PSI2017-85159-P (AEI/FEDER UE). K.B. was supported by a grant from the National Science Centre, Poland (number 2015/19/D/HS6/00641). J. Bonick and J.W.L. were supported by the Joep Lange Institute. G.B. was supported by the Slovak Research and Development Agency (APVV-17-0418). H.I.J. and E.S. were supported by a French National Research Agency ‘Investissements d’Avenir’ programme grant (ANR-15-IDEX-02). T.D.G. was supported by an Australian Government Research Training Program Scholarship. The Raipur Group is thankful to: (1) the University Grants Commission, New Delhi, India for the research grants received through its SAP-DRS (Phase-III) scheme sanctioned to the School of Studies in Life Science; and (2) the Center for Translational Chronobiology at the School of Studies in Life Science, PRSU, Raipur, India for providing logistical support. K. Ask was supported by a small grant from the Department of Psychology, University of Gothenburg. Y.Q. was supported by grants from the Beijing Natural Science Foundation (5184035) and CAS Key Laboratory of Behavioral Science, Institute of Psychology. N.A.C. was supported by the National Science Foundation Graduate Research Fellowship (R010138018). We acknowledge the following research assistants: J. Muriithi and J. Ngugi (United States International University Africa); E. Adamo, D. Cafaro, V. Ciambrone, F. Dolce and E. Tolomeo (Magna Græcia University of Catanzaro); E. De Stefano (University of Padova); S. A. Escobar Abadia (University of Lincoln); L. E. Grimstad (Norwegian School of Economics (NHH)); L. C. Zamora (Franklin and Marshall College); R. E. Liang and R. C. Lo (Universiti Tunku Abdul Rahman); A. Short and L. Allen (Massey University, New Zealand), A. Ateş, E. Güneş and S. Can Özdemir (Boğaziçi University); I. Pedersen and T. Roos (Åbo Akademi University); N. Paetz (Escuela de Comunicación Mónica Herrera); J. Green (University of Gothenburg); M. Krainz (University of Vienna, Austria); and B. Todorova (University of Vienna, Austria). The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.https://www.nature.com/nathumbehav/am2023BiochemistryGeneticsMicrobiology and Plant Patholog

Bluegill Population Demographics as Related to Abiotic and Biotic Factors in Florida Lakes

Research on Bluegills, Lepomis macrochirus R., is abundant but typically focuses on water bodies with similar environmental conditions. We assessed Bluegill density, relative abundance (catch per unit effort [CPUE] by electrofishing), growth, and size structure in 60 lakes with wide-ranging surface areas (2–12,412 ha), trophic states (oligotrophic–hypereutrophic), and macrophyte abundances (0.3–100 percent of lake volume inhabited [PVI]) across Florida, USA. Bluegill density and CPUE increased with lake productivity and decreased with macrophyte abundance. Bluegill growth increased with lake productivity and CPUE of stock-length Florida Bass, Micropterus floridanus L., a Bluegill predator. Bluegill size structure increased with lake productivity and decreased with Bluegill density. Results indicate that Bluegill fisheries with abundant individuals of quality size (≥150 mm) require productive (>25 μg/L chlorophyll-a concentration) lakes with moderate to high macrophyte coverage (PVI 50–100), abundant stock-length Florida Bass (>40 fish/h of electrofishing), and Bluegill densities <300 fish/ha. This study provides an approach to predict Bluegill population demographics based on abiotic and biotic factors, establish fisheries management expectations, and develop regional and lake-specific management tools

Possible Sediment Mixing and the Disparity between Field Measurements and Paleolimnological Inferences in Shallow Iowa Lakes in the Midwestern United States

Field measurements of water quality in Iowa lakes contradict paleolimnological studies that used 210Pb dating techniques in 33 lakes to infer accelerating eutrophication and sediment accumulation in recent decades. We tested this hypothesis by analyzing a series of water quality measurements taken in 24 of these lakes during the period 1972–2010. There was little change in the trophic state variables. Total phosphorus and algal chlorophylls did not increase, and Secchi depths did not decrease with no evidence that the lakes had become more eutrophic. Changes in daily sediment loads in the Raccoon River also did not match the paleolimnological inferred rates of soil erosion for the period 1905–2005, and an independent estimate of soil erosion rates showed a decline of 40% in the 1977 to 2012 period rather than an increase. We hypothesized that sediment mixing by benthivorous fish could be responsible for violating the basic assumption of 210Pb sediment dating that the sediments are not disturbed once they are laid down. We developed a mathematical model that demonstrated that sediment mixing could lead to false inferences about sediment dates and sediment burial rates. This study raises the possibility that sediment mixing in Iowa lakes and similar shallow, eutrophic lakes with benthivorous fish may cause significant sediment mixing that can compromise dating using 210Pb dating of sediment cores