| 1. |
- Tillfors, Maria, 1963-, et al.
(författare)
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Prospective links between social anxiety and adolescent peer relations
- 2012
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Ingår i: Journal of Adolescence. - : Academic Press. - 0140-1971 .- 1095-9254. ; 35:5, s. 1255-1263
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Tidskriftsartikel (refereegranskat)abstract
- This study examines bi-directional links between social anxiety and multiple aspects of peer relations (peer acceptance, peer victimization, and relationship quality) in a longitudinal sample of 1528 adolescents assessed twice with one year between (754 females and 774 males; M = 14.7 years of age). Lower levels of peer acceptance predicted increases in social anxiety. Social anxiety predicted decreases in relationship support for males and increases in peer victimization for females. Collectively our findings suggest that peers seem to play a significant role for adolescent mental health and social anxiety seems to interfere with healthy peer relations. Importantly, developmental pathways for social anxiety seem to differ for adolescent females and males.
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| 2. |
- Frisén, Ann, 1963, et al.
(författare)
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What actually makes bullying stop? Reports from former victims
- 2012
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Ingår i: Journal of Adolescence. - : Wiley. - 0140-1971 .- 1095-9254. ; 35:4, s. 981-990
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Tidskriftsartikel (refereegranskat)abstract
- School bullying is a serious, worldwide problem which is not easily counteracted. The present study focuses on the perspective of former victims, asking them what it was that made the bullying stop in their case. Participants were 273 18-year-old former victims in Sweden, a country in which schools are doing extensive work against bullying and the bullying prevalence is relatively low. Results showed that although support from school personnel was the most common reason that the former victims gave to why the bullying had ended, it was only mentioned by a fourth of them. In fact, it was almost equally as common that the bullying had ended in that the victims transitioned to a new school level or changed their way of coping with the bullying. Very few of the adolescents reported that the bullying had stopped due to support from peers. (C) 2012 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.
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| 3. |
- Fu, Michael, 1963, et al.
(författare)
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Functional autoimmune epitope on alpha 1-adrenergic receptors in patients with malignant hypertension.
- 1994
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Ingår i: Lancet. - 0140-6736. ; 344:8938, s. 1660-3
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Tidskriftsartikel (refereegranskat)abstract
- Because of the growing evidence that hypertensive disease is accompanied by immunological dysfunction, we have investigated autoimmunity in patients with malignant hypertension. Peptides corresponding to the sequence of the second extracellular loops of the human alpha 1-adrenergic receptor and the M2-muscarinic receptor were used as antigens in an ELISA. Serum from 4 (12%) of 33 healthy controls, 3 (20%) of 15 patients with malignant essential hypertension, and 7 (64%) of 11 with secondary hypertension showed positive responses in the ELISA for the alpha 1-adrenergic receptor peptide. Positive responses were significantly more common among the patients with secondary hypertension than in the other two groups (p < 0.01). By contrast, no autoantibodies against the M2-muscarinic receptor peptide were detected in either hypertensive group. Autoantibodies against the alpha 1-adrenergic receptor, affinity-purified from patients with positive responses, specifically recognised bands with molecular masses of 68, 40, and 37 kDa on immunoblotted membrane proteins of rat ventricles. The patients' autoantibodies caused a decrease in tritiated prazosin binding sites and an increase in heart beating frequency of neonatal cultured rat cardiomyocytes; antibodies purified from the controls had no effect. Circulating autoantibodies against the alpha 1-adrenergic receptor are present in a subgroup of patients with malignant hypertension. These autoantibodies have pharmacological activity in vitro, which suggests that they may be involved in the pathogenesis of malignant hypertension.
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| 4. |
- Alem, Yonas, 1974, et al.
(författare)
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Modeling household cooking fuel choice: A panel multinomial logit approach
- 2016
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Ingår i: Energy Economics. - : Elsevier BV. - 0140-9883. ; 59, s. 129-137
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Tidskriftsartikel (refereegranskat)abstract
- We use three rounds of a rich panel data set to investigate the determinants of household cooking fuel choice and energy transition in urban Ethiopia. We observe that the expected energy transition did not occur following economic growth in Ethiopia during the decade 2000–2009. Regression results from a random effects multinomial logit model, which controls for unobserved household heterogeneity, show that households' economic status, price of alternative energy sources, and education are important determinants of fuel choice in urban Ethiopia. The results also suggest the use of multiple fuels, or ‘fuel stacking behavior’. We argue that policy makers could target these policy levers to encourage transition to cleaner energy sources. © 2016 Elsevier B.V.
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| 5. |
- Blonde, Lawrence, et al.
(författare)
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Once-weekly dulaglutide versus bedtime insulin glargine, both in combination with prandial insulin lispro, in patients with type 2 diabetes (AWARD-4) : a randomised, open-label, phase 3, non-inferiority study
- 2015
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Ingår i: The Lancet. - New York, USA : Elsevier. - 0140-6736 .- 1474-547X. ; 385:9982, s. 2057-2066
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Tidskriftsartikel (refereegranskat)abstract
- Background: For patients with type 2 diabetes who do not achieve target glycaemic control with conventional insulin treatment, advancing to a basal-bolus insulin regimen is often recommended. We aimed to compare the efficacy and safety of long-acting glucagon-like peptide-1 receptor agonist dulaglutide with that of insulin glargine, both combined with prandial insulin lispro, in patients with type 2 diabetes.Methods: We did this 52 week, randomised, open-label, phase 3, non-inferiority trial at 105 study sites in 15 countries. Patients (aged ≥18 years) with type 2 diabetes inadequately controlled with conventional insulin treatment were randomly assigned (1:1:1), via a computer-generated randomisation sequence with an interactive voice-response system, to receive once-weekly dulaglutide 1·5 mg, dulaglutide 0·75 mg, or daily bedtime glargine. Randomisation was stratified by country and metformin use. Participants and study investigators were not masked to treatment allocation, but were unaware of dulaglutide dose assignment. The primary outcome was a change in glycated haemoglobin A1c (HbA1c) from baseline to week 26, with a 0·4% non-inferiority margin. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT01191268.Findings: Between Dec 9, 2010, and Sept 21, 2012, we randomly assigned 884 patients to receive dulaglutide 1·5 mg (n=295), dulaglutide 0·75 mg (n=293), or glargine (n=296). At 26 weeks, the adjusted mean change in HbA1c was greater in patients receiving dulaglutide 1·5 mg (-1·64% [95% CI -1·78 to -1·50], -17·93 mmol/mol [-19·44 to -16·42]) and dulaglutide 0·75 mg (-1·59% [-1·73 to -1·45], -17·38 mmol/mol [-18·89 to -15·87]) than in those receiving glargine (-1·41% [-1·55 to -1·27], -15·41 mmol/mol [-16·92 to -13·90]). The adjusted mean difference versus glargine was -0·22% (95% CI -0·38 to -0·07, -2·40 mmol/mol [-4·15 to -0·77]; p=0·005) for dulaglutide 1·5 mg and -0·17% (-0·33 to -0·02, -1·86 mmol/mol [-3·61 to -0·22]; p=0·015) for dulaglutide 0·75 mg. Five (<1%) patients died after randomisation because of septicaemia (n=1 in the dulaglutide 1·5 mg group); pneumonia (n=1 in the dulaglutide 0·75 mg group); cardiogenic shock; ventricular fibrillation; and an unknown cause (n=3 in the glargine group). We recorded serious adverse events in 27 (9%) patients in the dulaglutide 1·5 mg group, 44 (15%) patients in the dulaglutide 0·75 mg group, and 54 (18%) patients in the glargine group. The most frequent adverse events, arising more often with dulaglutide than glargine, were nausea, diarrhoea, and vomiting.Iinterpretation: Dulaglutide in combination with lispro resulted in a significantly greater improvement in glycaemic control than did glargine and represents a new treatment option for patients unable to achieve glycaemic targets with conventional insulin treatment.FUNDING: Eli Lilly and Company.
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| 6. |
- Carlsson, Johanna, 1985, et al.
(författare)
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Life on hold: Staying in identity diffusion in the late twenties
- 2016
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Ingår i: Journal of Adolescence. - : Wiley. - 0140-1971 .- 1095-9254. ; 47, s. 220-229
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Tidskriftsartikel (refereegranskat)abstract
- This study adds to the understanding of the dark side of identity development by investigating what it means to experience long-term identity diffusion during the late twenties. In a study of change and stability in identity status between ages 25 and 29 (N ¼ 124; 63 women), seven participants were assigned to identity diffusion at both ages. Longitudinal analysis of interviews with these participants showed that long-term experiences of identity diffusion may be described through individuals' approach to changing life conditions, the extent to which they engage in meaning making, and how they develop their personal life direction. In questionnaires, participants reported few signs of psychological distress. Even so, qualitative analyses showed a general trend among participants to keep life on hold through decreased activity or increased haphazard activity in relation to changing life conditions, to make little new meaning, and in some cases to dissolve their personal life direction.
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| 7. |
- Gebreegziabher, Zenebe, et al.
(författare)
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Urban energy transition and technology adoption: The case of Tigrai, northern Ethiopia
- 2012
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Ingår i: Energy Economics. - 0140-9883. ; 34:2, s. 410-418
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Tidskriftsartikel (refereegranskat)abstract
- Dependency of urban Ethiopian households on rural areas for about 85% of their fuel needs is a significant cause of deforestation and forest degradation, resulting in growing fuel scarcity and higher firewood prices. One response to reducing the pressure on rural lands is for urban households to switch fuel sources, for example, from wood fuel to electricity, to slow deforestation and forest degradation and reduce indoor air pollution. However, such an energytransition is conditioned on the adoption of appropriate cooking appliances or stove technologies by the majority of users. This paper investigates urbanenergytransition and technology adoption conditions using a dataset of 350 urban households in Tigrai, in northernEthiopia. Results suggest that the transition to electricity is affected by households adopting the electric mitad cooking appliance, which in turn is influenced by the level of education and income, among other things.
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| 8. |
- Ghezzi, Pietro, et al.
(författare)
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Erythropoietin: not just about erythropoiesis
- 2010
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Ingår i: LANCET. - 0140-6736. ; 375:9732, s. 2142-2142
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Tidskriftsartikel (refereegranskat)abstract
- Referred to by Department of Error, The Lancet, Volume 376, Issue 9739, 7–13 August 2010, Page 418
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| 9. |
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| 10. |
- Hassen, S., et al.
(författare)
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Does purchase price matter for the waiting time to start using energy efficient technologies: Experimental evidence from rural Ethiopia?
- 2017
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Ingår i: Energy Economics. - : Elsevier BV. - 0140-9883. ; 68, s. 133-140
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Tidskriftsartikel (refereegranskat)abstract
- In this study we conducted a randomized experiment in rural Ethiopia to test on how quickly energy efficient technology (an improved stove) is put in use after the technologies is disseminated. We evaluate two concepts that may affect usage of a product: screening (related to valuation of a product) and sunk cost effects (based on the price the potential user paid for the product). A standard Tobit and IV-Tobit methods of estimations are used for testing sunk cost and screening effects, respectively. Results based on the baseline survey and follow up data shows that there is no difference in the length of waiting time to start using the energy efficient technology between those who got the stove for free and those that paid money for it; in other words, the sunk cost effect is absent. However, we find a difference in the waiting time between those with high valuation for the stove and those with lower valuation for it; in other words, we find an evidence of the screening effect. The result has pricing policy implications for government and non-government organizations involved in dissemination of such technologies that have both public (environmental) and private benefits. (C) 2017 Elsevier B.V. All rights reserved.
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| 11. |
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| 12. |
- Swen, JesseJ, et al.
(författare)
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A 12-gene pharmacogenetic panel to prevent adverse drug reactions : an open-label, multicentre, controlled, cluster-randomised crossover implementation study
- 2023
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Ingår i: The Lancet. - : Elsevier. - 0140-6736 .- 1474-547X. ; 401:10374, s. 347-356
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Tidskriftsartikel (refereegranskat)abstract
- Background: The benefit of pharmacogenetic testing before starting drug therapy has been well documented for several single gene-drug combinations. However, the clinical utility of a pre-emptive genotyping strategy using a pharmacogenetic panel has not been rigorously assessed.Methods: We conducted an open-label, multicentre, controlled, cluster-randomised, crossover implementation study of a 12-gene pharmacogenetic panel in 18 hospitals, nine community health centres, and 28 community pharmacies in seven European countries (Austria, Greece, Italy, the Netherlands, Slovenia, Spain, and the UK). Patients aged 18 years or older receiving a first prescription for a drug clinically recommended in the guidelines of the Dutch Pharmacogenetics Working Group (ie, the index drug) as part of routine care were eligible for inclusion. Exclusion criteria included previous genetic testing for a gene relevant to the index drug, a planned duration of treatment of less than 7 consecutive days, and severe renal or liver insufficiency. All patients gave written informed consent before taking part in the study. Participants were genotyped for 50 germline variants in 12 genes, and those with an actionable variant (ie, a drug-gene interaction test result for which the Dutch Pharmacogenetics Working Group [DPWG] recommended a change to standard-of-care drug treatment) were treated according to DPWG recommendations. Patients in the control group received standard treatment. To prepare clinicians for pre-emptive pharmacogenetic testing, local teams were educated during a site-initiation visit and online educational material was made available. The primary outcome was the occurrence of clinically relevant adverse drug reactions within the 12-week follow-up period. Analyses were irrespective of patient adherence to the DPWG guidelines. The primary analysis was done using a gatekeeping analysis, in which outcomes in people with an actionable drug-gene interaction in the study group versus the control group were compared, and only if the difference was statistically significant was an analysis done that included all of the patients in the study. Outcomes were compared between the study and control groups, both for patients with an actionable drug-gene interaction test result (ie, a result for which the DPWG recommended a change to standard-of-care drug treatment) and for all patients who received at least one dose of index drug. The safety analysis included all participants who received at least one dose of a study drug. This study is registered with ClinicalTrials.gov, NCT03093818 and is closed to new participants.Findings: Between March 7, 2017, and June 30, 2020, 41 696 patients were assessed for eligibility and 6944 (51.4 % female, 48.6% male; 97.7% self-reported European, Mediterranean, or Middle Eastern ethnicity) were enrolled and assigned to receive genotype-guided drug treatment (n=3342) or standard care (n=3602). 99 patients (52 [1.6%] of the study group and 47 [1.3%] of the control group) withdrew consent after group assignment. 652 participants (367 [11.0%] in the study group and 285 [7.9%] in the control group) were lost to follow-up. In patients with an actionable test result for the index drug (n=1558), a clinically relevant adverse drug reaction occurred in 152 (21 center dot 0%) of 725 patients in the study group and 231 (27.7%) of 833 patients in the control group (odds ratio [OR] 0 center dot 70 [95% CI 0 center dot 54-0 center dot 91]; p=0.0075), whereas for all patients, the incidence was 628 (21.5%) of 2923 patients in the study group and 934 (28. 6%) of 3270 patients in the control group (OR 0.70 [95% CI 0.61-0.79]; p <0.0001).Interpretation: Genotype-guided treatment using a 12-gene pharmacogenetic panel significantly reduced the incidence of clinically relevant adverse drug reactions and was feasible across diverse European health-care system organisations and settings. Large-scale implementation could help to make drug therapy increasingly safe.
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| 13. |
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| 14. |
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| 15. |
- Wängqvist, Maria, 1977, et al.
(författare)
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Swedish 18-year-olds’ identity formation: Associations with feelings about appearance and internalization of body ideals
- 2013
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Ingår i: Journal of Adolescence. - 0140-1971 .- 1095-9254. ; 36, s. 485-493
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study with Swedish 18-year-olds (N = 714, 55.2% women) was to investigate identity formation in relation to body-esteem and body ideal internalization. These are all important aspects of adolescents’ development, but little is known about how they are related. This study indicates that late adolescents’ identity formation, body-esteem, and body ideal internalizations are related. Women’s interpersonal identity commitments and explorations were related to more positive thoughts about how others evaluate their appearance. Their interpersonal identity explorations were also related to more internalization of societal body ideals. For men, stronger interpersonal identity commitments were related to more positive own evaluations about their appearance. The results also showed that compared to men, women explored identity issues more, had poorer body-esteem, and had internalized body ideals more.
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| 16. |
- Yamaguchi, M., et al.
(författare)
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Non-invasive monitoring of gingival crevicular fluid for estimation of blood glucose level
- 2004
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Ingår i: Medical and Biological Engineering and Computing. - : Springer. - 0140-0118 .- 1741-0444. ; 42:3, s. 322-327
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Tidskriftsartikel (refereegranskat)abstract
- Development of a non-invasive method for measuring the blood glucose level is an urgent necessity, and putting such a method into practical use will enable some of the physical and mental stress that patients with diabetes have to endure to be removed. To realise a non-invasive blood glucose monitor, the gingival crevicular fluid (GCF) was measured. A GCF-collecting device was developed that was designed to be disposable, biocompatible and small enough to be inserted in the gingival crevice for collection of a sub-microlitre sample of GCF. Also, a high-sensitivity glucose testing tape incorporated in the device was developed. Red laser light in a portable optical device measured the colour density of the testing tape. Standard glucose solutions were used to investigate the measurement accuracy of the GCF glucose monitor and showed a correlation coefficient of R=0.99 (n=20) between the optical density and the glucose levels. The GCF glucose monitor was evaluated on healthy Swedish and Japanese adults (n=10) and both GCF glucose levels (GCFLs) and blood glucose levels (BGLs) were measured in conjunction with meal loads. The GCFLs were about 1/10-1/560 lower than the BGLs. No difference in the range of GCFLs between the Swedish and the Japanese subjects was observed. Therefore it was concluded that physique, body mass index and life-style, such as dietary habit, did not significantly influence the GCFLs. Further, the correlation coefficients of all the subjects were 0.70 and 0.88 with each group. It was suggested that GCF could be used as a method of non-invasive blood glucose measurement.
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| 17. |
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| 18. |
- Aarrestad, P. A., et al.
(författare)
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Influence of soil, tree cover and large herbivores on field layer vegetation along a savanna landscape gradient in northern Botswana
- 2011
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Ingår i: Journal of Arid Environments. - : Elsevier BV. - 0140-1963 .- 1095-922X. ; 75:3, s. 290-297
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Tidskriftsartikel (refereegranskat)abstract
- The response of the field layer vegetation to co-varying resource availability (soil nutrients, light) and resource loss (herbivory pressure) was investigated along a landscape gradient highly influenced by elephants and smaller ungulates at the Chobe River front in Botswana. TWINSPAN classification was used to identify plant communities. Detrended Correspondence Analysis (DCA) and Canonical Correspondence Analysis (CCA) were used to explore the vegetation-environment relationships. Four plant communities were described: Panicum maximum woodland, Tribulus terrestris woodland/shrubland, Chloris virgata shrubland and Cynodon dactylon floodplain. Plant height, species richness and diversity decreased with increasing resource availability and resource loss. The species composition was mainly explained by differences in soil resources, followed by variables related to light availability (woody cover) and herbivory, and by interactions between these variables. The vegetation structure and species richness, on the other hand, followed the general theories of vegetation responses to herbivory more closely than resource related theories. The results suggest a strong interaction between resource availability and herbivory in their influence on the composition, species richness and structure of the plant communities.
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| 19. |
- Angeler, David
(författare)
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Nutrient contents and export from streams in semiarid catchments of central Spain
- 2010
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Ingår i: Journal of Arid Environments. - : Elsevier BV. - 0140-1963 .- 1095-922X. ; 74, s. 933-945
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Tidskriftsartikel (refereegranskat)abstract
- Thirty five catchments in semiarid Central Spain were monitored monthly in late winter and spring to search for relationships between environmental variables (sedimentary nutrients and hydrological topographical, geological, pedological, land use factors) and nutrient concentrations and exports. Results enabled to outline differences between semiarid and moist catchments. the latter drawn from other studies While land use, topography and ecotone features explained an important fraction of overall variance of nutrients in moist areas, geological and pedological features were much better descriptors in semiarid catchments Runoff explained most variability of total carbon, organic carbon and nitrogen export, and soil types and carbon and phosphorus contents stored in stream sediments best explained total phosphorus, dissolved- and particulate organic carbon export in semiarid catchments. In moist catchments geology, climate, pedology and land use were shown to influence nutrient export Hydrology potentially swamped effects related to land use and landscape structure (i e topographical, geological and soil factors). Thus nutrient concentration and export in semiarid catchments deviate from those in moist catchments which is due to the overriding effects of hydrological features, geology and pedology Further research, including the application of combined GIS techniques and modeling approaches, is needed to generalize our findings over other semiarid areas (C) 2010 Elsevier Ltd All rights reserved
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| 20. |
- Ardö, Jonas, et al.
(författare)
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Assessment of soil organic carbon in semi-arid Sudan using GIS and the CENTURY model
- 2003
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Ingår i: Journal of Arid Environments. - : Elsevier BV. - 1095-922X .- 0140-1963. ; 54:4, s. 633-651
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Tidskriftsartikel (refereegranskat)abstract
- Using the UNFCCC as a basis, and the objectives of estimating soil organic carbon (SOC) changes during the period 1900-2100, a spatially explicit database of climate, land cover and soil texture was compiled for a 262,000 km(2) region in semi-arid Sudan. The area is characterized by low input cultivation of millet, sorghum and sesame combined with livestock grazing. By integrating the database with the CENTURY ecosystem model, we were able to estimate historical, current and future pools of SOC as a function of land management and climate. The SOC (upper 20 cm) decrease from 1900 to 2000 was estimated to be 6.8 Mt and the maximum potential carbon sink (SOC increase) for the period 2000 to 2 100 was estimated to be 17 Mt. Cropland and grassland lost 293 and 152t SOC km(-2) respectively whereas the savannahs gained 76t SOC km(-2) from 1900 to 2000. The SOC sequestration scenario simulated during 2000-2100 recovered 94, 84 and 75 tkm(-2) for cropland, grassland and savannah respectively. In addition to climate and soils, cropping intensity, fallow periods, fire frequency and grazing intensity also influence cropland SOC variation. Grassland and savannah SOC variations depend on grazing intensity and fire return interval. Land management may affect future amounts of SOC in semi-arid areas thereby turning them from sources into sinks of carbon. SOC estimates were reasonably consistent with measurements (r(2) = 0.70, n = 13).
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| 21. |
- Dalerum, Fredrik, et al.
(författare)
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Spatial and temporal dimensions to the taxonomic diversity of arthropods in an arid grassland savannah
- 2017
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Ingår i: Journal of Arid Environments. - : Elsevier BV. - 0140-1963 .- 1095-922X. ; 144, s. 21-30
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Tidskriftsartikel (refereegranskat)abstract
- Quantifying the drivers of biodiversity variation is a key topic in contemporary ecology. While the geographic distribution of biodiversity is broadly determined by water and energy, local environmental conditions may be important. We evaluated the relative effects of spatial and temporal variation on taxonomic diversity of ground living arthropod communities in central South Africa. Seasonal climate variation was a major driver of arthropod abundance, but seasonal effects differed between habitats. We did not find any evidence for modular community structures, even across different habitats, or any evidence for a nested pattern across seasons. Instead, we observed a spatial nestedness which was only partly related to specific habitats. Our results suggest that neutral processes had influenced arthropod community structure, but also that very local processes may have been pivotal in determining local and regional arthropod diversity. Such processes may not necessarily have been neutral, but could have been caused by niche deterministic processes acting at scales smaller the distinct habitat classes we used for our study. We further suggest that alterations in climate likely will have substantial effects on the spatial and temporal distribution of arthropod diversity in this arid region.
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| 22. |
- El Tahir, B. A., et al.
(författare)
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Changes in soil properties following conversion of Acacia senegal plantation to other land management systems in North Kordofan State, Sudan
- 2009
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Ingår i: Journal of Arid Environments. - : Elsevier BV. - 1095-922X .- 0140-1963. ; 73:4-5, s. 499-505
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Tidskriftsartikel (refereegranskat)abstract
- Changes in soil texture, bulk density, pH, concentrations and stocks of OC, N, P and K before and after conversion of a 6-year-old Acacia senegal plantation to other land management systems (LMS) were investigated, after three cropping seasons, in the drylands of western Sudan. LMS included pure and intercropped sorghum (PS), roselle (PR) and grasses (PC) with A. senegal at high and low-tree densities (HD 433 and LD 266 trees ha(-1)). Significant changes included increase in coarse sand and a decrease in fine sand under pure and intercropped systems at LD: decrease in clay contents in PS and PR: an increase in clay ratio in all pure crops and HD + R; a decrease in aggregated mean concentrations of OC, N and P under all LMS by 42%, 68% and 45%, respectively; increase in soil pH under all LMS: a depletion of aggregated mean stocks of OC, N, P and K in all LMS by 38%, 30%, 52% 13%, respectively. The study established that wholesale tree clearance constitutes a major cause of soil degradation, and tree inputs and cycling of nutrients are of major importance to soil fertility in the study area. (C) 2008 Elsevier Ltd. All rights reserved.
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| 23. |
- Elmqvist, Bodil, et al.
(författare)
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The possibilities of bush fallows with changing roles of agriculture - An analysis combining remote sensing and interview data from Sudanese drylands
- 2007
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Ingår i: Journal of Arid Environments. - : Elsevier BV. - 1095-922X .- 0140-1963. ; 70:2, s. 329-343
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Tidskriftsartikel (refereegranskat)abstract
- The lengths of fallows have decreased in many parts of the Sahel due to agricultural expansion, which can have negative impacts on crop production when few other ways to improve soil fertility exist. However, the dynamics of agricultural expansion may change because of the changing role of agriculture in society due to increased livelihood diversification outside of agriculture. The results of this study, which combine very high resolution satellite images and interview data, show that the role of agriculture has changed in parts of central Sudan since the crop production per capita declined substantially during the past three decades. It is argued that this decline is linked to the increase in incomes from off-farm activities during the same period. The reduced role of agriculture implies that the majority of households have more than half of the land lying in fallow; however the amount of fallow land per household varies considerably. This has specific value for the debate about Acacia senegal bush fallows in Sudan since with respect to the availability of land, a potential for these fallows was shown.
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| 24. |
- Eshete, Getachew, et al.
(författare)
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Wood biomass functions for Acacia abyssinica trees and shrubs and implications for provision of ecosystem services in a community managed exclosure in Tigray, Ethiopia
- 2013
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Ingår i: Journal of Arid Environments. - : Elsevier BV. - 0140-1963 .- 1095-922X. ; 94, s. 80-86
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Tidskriftsartikel (refereegranskat)abstract
- In the Ethiopian highlands, remarkable recovery of vegetation has been achieved using exclosures, protecting vegetation against livestock browsing and firewood harvesting. But these emerging forest resources require tools for sustainable use, implying knowledge on biomass stocks and growth. In this study we developed biomass functions estimating total, stem and branch biomass from diameter at stump height (DSH) and tree height (H) for an 11-year old exclosure in Tigray, Ethiopia. In a systematic grid of 55 plots, DSH and H of all trees and shrubs were recorded. 40 Acacia abyssinica trees were selected for destructive sampling. Allometric relationships using a natural log-log model were established between aboveground biomass, DSH and H. Models with only DSH were found best with R-2 between 0.95 and 0.98. The functions were 10 fold cross-validated and R-2_cv ranged from 0.94 to 0.97, indicating good model performance. The models were found well in range with those of other seasonal forests in East Africa. Total aboveground biomass was estimated 25.4 ton ha(-1) with an annual production of 2.3 ton ha(-1), allowing sustainable wood fuel use for 4 persons ha(-1). The presented predictive functions help to harmonize between ecological and societal objectives and are as such a first step towards an integrated planning tool for exclosures. (C) 2013 Elsevier Ltd. All rights reserved.
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| 25. |
- Florentine, SK, et al.
(författare)
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Decade-long response of arid-land mallee vegetation to fire, flooding and grazing in south-eastern Australia
- 2015
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Ingår i: Journal of Arid Environments. - : Elsevier. - 0140-1963 .- 1095-922X. ; 121, s. 7-14
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Tidskriftsartikel (refereegranskat)abstract
- Australian arid vegetation has evolved within highly variable environments characterised by low rainfall and sporadic fire events. Episodic high rainfall events are a significant factor in plant species recruitment, but their unpredictability makes them difficult to study. We report on the response of vascular plants to a major rainfall event and flood in an arid region of south-eastern Australia. Fire that occurred two months before the flood was incorporated into the study. Paired fenced and unfenced plots were established at control locations and also in areas that had been either flooded, burnt, or flooded and burnt. Objectives were to quantify the long-term effects of fire, flood and vertebrate herbivory, and their interactions, on vegetation composition, plant life forms and species diversity. We found that relative to controls (i) there was a significant effect of flooding on vegetation composition, (ii) changes in life form abundance were driven by flooding and grazing, (iii) there was a strong positive relationship between grazer exclusion and species diversity that was maintained over time and (iv) there was little effect of fire. Understanding the long-term effects of both natural disturbances and vertebrate herbivory will benefit plant conservation in the arid zone.
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