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- Correa, D. F., et al.
(författare)
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Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates
- 2023
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Ingår i: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 32:1, s. 49-69
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Tidskriftsartikel (refereegranskat)abstract
- Aim To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis). Time period Tree-inventory plots established between 1934 and 2019. Major taxa studied Trees with a diameter at breast height (DBH) >= 9.55 cm. Location Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests. Main conclusions The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types.
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| 4. |
- Van, den Berg M, et al.
(författare)
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Toxic equivalency factors (TEFs) for PCBs, PCDDs, PCDFs for humans and wildlife
- 1998
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Ingår i: ENVIRONMENTAL HEALTH PERSPECTIVES. - : US DEPT HEALTH HUMAN SERVICES PUBLIC HEALTH SERVICE. ; 106:12, s. 775-792
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Recension (övrigt vetenskapligt/konstnärligt)abstract
- An expert meeting was organized by the World Health Organization (WHO) and held in Stockholm on 15-18 June 1997. The objective of this meeting was to derive consensus toxic equivalency factors (TEFs) for polychlorinated dibenzo-p-dioxins (PCDDs) and diben
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| 8. |
- Silva, A. V., et al.
(författare)
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Dose-dependent toxicological effects in rats following a 90-day dietary exposure to PCB-156 include retinoid disruption
- 2021
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Ingår i: Toxicology Letters. - : Elsevier. - 0378-4274 .- 1879-3169. ; 350:Suppl., s. S163-S163
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The toxicity of PCB-156 (2,3,3¢,4,4¢,5-hexachlorobiphenyl) was investigated in rats following subchronic dietary exposure. Groups of 10 male and 10 female Sprague-Dawley rats were administered PCB in the diet at 0, 0.01, 0.1, 1 or 10 ppm for 13 weeks. Results were analysed by group-wise comparison and benchmark dose-modelling. The latter revealed ose-related decreases of final body weight, growth rate and thymus weight. Additionally, rats receiving PCB-156 showed dose-dependent weight increases of liver, lungs and kidneys. Biochemical changes included increases in liver EROD, PROD and UD-PGT enzymatic activities, as well as increases in uro-porphyrin. Retinoid (Vitamin A) quantification showed a clear and treatment-related reduction of the levels in the liver and lungs, as well as increased levels in the kidneys. A owest-observable-adverse-effect level (LOAEL) of 0.01 ppm was established, based on effects in the liver apolar retinoids concentration, corresponding to dietary exposure of 0.7 and 0.8 μg PCB-156/kg body weight per dayin male and female rats, respectively. Benchmark dose-modelling corroborated effects in the retinoid system, in both sexes, at even lower intake levels. The lower confidence limit (BMDL) for a 5% decrease in the concentration of liver apolar retinoids was 0.00086 (males) and 0.00068 ppm (fe-males), corresponding to a daily exposure of 0.06 μg PCB-156/kg body weight for both sexes. This BMDL5 is approximately 10-fold lower than the LOAEL for PCB-156. Based on the retinoid system’s susceptibility to PCB-156 exposure, we recommend effects on this system to be considered as critical for risk assessment of PCB-156 and other PCB congeners.
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| 9. |
- Vieira Silva, A., et al.
(författare)
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Dose-dependent toxicological effects in rats following a 90-day dietary exposure to PCB-156 include retinoid disruption
- 2022
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Ingår i: Reproductive Toxicology. - : Elsevier. - 0890-6238 .- 1873-1708. ; 107, s. 123-139
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Tidskriftsartikel (refereegranskat)abstract
- The toxicity of PCB-156 (2,3,3',4,4',5-hexachlorobiphenyl) was investigated in rats following subchronic dietary exposure. Groups of 10 male and female Sprague-Dawley rats were administered PCB-156 in the diet at 0, 0.01, 0.1, 1 or 10 ppm for 90 days. Dose-dependent increases were detected for the liver, lung and kidney weights, as well as for the liver EROD, PROD and UDPGT enzyme activities and liver uroporphyrin concentration. Dose-dependent decreases were observed in final body weight, body weight gain, and thymus weight. Apolar retinoid concentrations were decreased in the liver and lungs and increased in the kidneys. Histopathological examination of the liver, thyroid, and thymus showed mild to moderate dose-related changes.A LOAEL of 0.01 ppm was established, based on reduced apolar liver retinoid concentration. Benchmark dose-modelling corroborated the sensitivity of liver retinoid endpoints. The lower confidence limits (BMDL) for a 5% decrease in apolar liver retinoid concentrations were 0.0009 and 0.0007 ppm, respectively, in males and females, corresponding to a daily dose of 0.06 µg PCB-156 per kg body weight. Organizing dose-response data for the individual hepatic endpoints along the PCB-156 dosing scale revealed a sequence of events compatible with a causal link between depletion of apolar retinoids and the other liver biochemistry and pathology findings. Taken together, data suggest that the retinoid endpoints should be further evaluated for a causal relationship to PCB-induced liver toxicity and that retinoid system endpoints are identified and characterized to support health risk assessment in the emerging research fields of endocrine disruption and mixture toxicology.
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| 10. |
- Brahim, Lydia Ould, et al.
(författare)
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The effects of self-management interventions on depressive symptoms in adults with chronic physical disease(s) experiencing depressive symptomatology : a systematic review and meta-analysis
- 2021
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Ingår i: BMC Psychiatry. - : BioMed Central (BMC). - 1471-244X. ; 21:1
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Forskningsöversikt (refereegranskat)abstract
- Background Chronic diseases are the leading cause of death worldwide. It is estimated that 20% of adults with chronic physical diseases experience concomitant depression, increasing their risk of morbidity and mortality. Low intensity psychosocial interventions, such as self-management, are part of recommended treatment; however, no systematic review has evaluated the effects of depression self-management interventions for this population. The primary objective was to examine the effect of self-management interventions on reducing depressive symptomatology in adults with chronic disease(s) and co-occurring depressive symptoms. Secondary objectives were to evaluate the effect of these interventions on improving other psychosocial and physiological outcomes (e.g., anxiety, glycemic control) and to assess potential differential effect based on key participant and intervention characteristics (e.g., chronic disease, provider). Methods Studies comparing depression self-management interventions to a control group were identified through a) systematic searches of databases to June 2018 [MEDLINE (1946 -), EMBASE (1996 -), PsycINFO (1967 -), CINAHL (1984 -)] and b) secondary 'snowball' search strategies. The methodological quality of included studies was critically reviewed. Screening of all titles, abstracts, and full texts for eligibility was assessed independently by two authors. Data were extracted by one author and verified by a second. Results Fifteen studies were retained: 12 for meta-analysis and three for descriptive review. In total, these trials included 2064 participants and most commonly evaluated interventions for people with cancer (n = 7) or diabetes (n = 4). From baseline to < 6-months (T1), the pooled mean effect size was - 0.47 [95% CI -0.73, - 0.21] as compared to control groups for the primary outcome of depression and - 0.53 [95% CI -0.91, - 0.15] at >= 6-months (T2). Results were also significant for anxiety (T1) and glycemic control (T2). Self-management skills of decision-making and taking action were significant moderators of depression at T1. Conclusion Self-management interventions show promise in improving depression and anxiety in those with concomitant chronic physical disease. The findings may contribute to the development of future Self-management interventions and delivering evidence-based care to this population. Further high-quality RCTs are needed to identify sources of heterogeneity and investigate key intervention components.
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