115 research outputs found
Applying Fishers' Ecological Knowledge to Construct Past and Future Lobster Stocks in the Juan Fernández Archipelago, Chile
Over-exploited fisheries are a common feature of the modern world and a range of solutions including area closures (marine reserves; MRs), effort reduction, gear changes, ecosystem-based management, incentives and co-management have been suggested as techniques to rebuild over-fished populations. Historic accounts of lobster (Jasus frontalis) on the Chilean Juan Fernández Archipelago indicate a high abundance at all depths (intertidal to approximately 165 m), but presently lobsters are found almost exclusively in deeper regions of their natural distribution. Fishers' ecological knowledge (FEK) tells a story of serial depletion in lobster abundance at fishing grounds located closest to the fishing port with an associated decline in catch per unit effort (CPUE) throughout recent history. We have re-constructed baselines of lobster biomass throughout human history on the archipelago using historic data, the fishery catch record and FEK to permit examination of the potential effects of MRs, effort reduction and co-management (stewardship of catch) to restore stocks. We employed a bioeconomic model using FEK, fishery catch and effort data, underwater survey information, predicted population growth and response to MR protection (no-take) to explore different management strategies and their trade-offs to restore stocks and improve catches. Our findings indicate that increased stewardship of catch coupled with 30% area closure (MR) provides the best option to reconstruct historic baselines. Based on model predictions, continued exploitation under the current management scheme is highly influenced by annual fluctuations and unsustainable. We propose a community-based co-management program to implement a MR in order to rebuild the lobster population while also providing conservation protection for marine species endemic to the Archipelago
Nest building and description of parental care behavior in a temperate reef fish, Chromis crusma (Pisces: Pomacentridae)
A quantitative synthesis of approaches, biases, successes, and failures in marine forest restoration, with considerations for future work
A quantitative synthesis of approaches, biases, successes, and failures in marine forest restoration, with considerations for future work
1. Marine forests is a term commonly used for coastal marine habitats formed by dense stands of brown macroalgae, typically consisting of kelp and fucoids. These habitats are highly productive, offer habitat to numerous marine organisms, and support a range of invaluable ecosystem services. Despite their importance, marine forests are declining in many regions around the world as a result of interacting global, regional, and local-scale stressors. Consequently, interest in restoration as a tool to mitigate these declines and reinstate marine forests is growing.
2. Recent reviews have provided insights into marine forest restoration; however, for the most part, a synthesis of restoration success is lacking. A meta-analysis and quantitative review of published marine forest restoration efforts was conducted to examine: (i) how restoration affects the abundance and morphology of marine forest species; and (ii) trends in marine forest restoration success.
3. The meta-analysis of 25 studies revealed that restoration positively influences the abundance and morphology of marine forest species. The quantitative review of 63 studies demonstrated that taxa and restoration technique were important factors influencing restoration success, and revealed a bias towards the monitoring and reporting of abundance and morphological response variables. The review also highlighted a lack of monitoring and/or reporting of environmental variables at restoration sites, and limited comparative research across environmental contexts and restored species.
4. It is shown that successful marine forest restoration is possible at experimental scales, but that better monitoring and reporting of restoration efforts, alongside increased project durations, could improve our understanding of restoration success at the ecosystem level. Considerations for future marine forest restoration efforts are also provided. It is hoped that the review will advance marine forest restoration efforts, allowing the preservation of these valuable ecosystems and their associated services
Relación entre el bienestar y el rendimiento académico en alumnos de primer año de medicina
Background: Stress may affect the sense of wellbeing and academic achievement of university students. Aim: To assess the relationship of academic engagement and burnout with academic achievement among first year medical students. Material and Methods: The Utrecht Work Engagement Scale-Student and Maslach Burnout Inventory Student Survey (MBI-SS) were applied to 277 first year medical students of four universities. Their results were correlated with the grades obtained in the different courses. Results: Moderately high engagement and low burnout levels were detected. There was a high level of satisfaction with studies and a moderate exhaustion level. Academic achievement was associated with the degree of engagement with studies but not with burnout. Conglomerate analysis detected a group of students with high levels of wellbeing, characterized by high levels of academic engagement and low burnout. Other group had moderate levels of engagement and lack of personal fulfilment. Other group, identified as extenuated, had high levels of personal exhaustion and depersonalization. Finally the disassociated group had a low academic engagement, low emotional exhaustion, high levels of depersonalization and lack of personal fulfillment. Conclusions: Academic achievement is associated with the level of engagement with studies but not with burnout
Factorial structure and reliability of the academic satisfaction questionnaire on Chilean medical students
Indexación: Web of Science; Scopus.El presente estudio analiza la estructura factorial y confiabilidad del cuestionario de satisfacción
académica (CSA) en una muestra de 563 estudiantes de medicina, entre 19 y 29 años (media de 20,42);
provenientes de cuatro universidades chilenas. Una vez finalizada la traducción al castellano se exploró
la validez de contenido de los ítems mediante un juicio de expertos. La estructura factorial del cuestionario
se analizó a través de un análisis factorial exploratorio empleando el método Análisis de Ejes
Principales (AEP). Los resultados preliminares de la fiabilidad y validez del instrumento han mostrado
que la estructura de un factor es viable y adecuada de acuerdo a los requisitos psicométricos establecidos,
aunque se recomiendan futuros estudios que evalúen su validez y confiabilidad en otros programas
de pregrado.The present study examines the factorial structure and reliability of the academic satisfaction questionnaire
(CSA) in a sample of 563 medical students, between 19 and 29 years (average of 20.42); from
four Chilean universities. Once translated into Spanish explored the validity of the items content was
evaluated through experts opinions. The factorial structure of the scale was analyzed through an exploratory
factor analysis using the Principal Axis Analysis method (AEP).The preliminary results of the
reliability and validity of the instrument have shown that a factor structure is viable and appropriate
according to the established psychometric requirements, although future studies to evaluate its validity
and reliability in other undergraduate programs are recommended.http://www.redalyc.org/articulo.oa?id=45964543200
Evaluación de la erosión hídrica del suelo en la finca “Santos García” ubicada en el cerro Las Mesas, Matagalpa, mediante el uso del radionucleido ambiental 137Cesio
Encuentro No. 99, 57-69, 2014Se evaluó el proceso de erosión hídrica presente en la finca “Santos García”, Ciudad Darío, Matagalpa. Para cuantificar las pérdidas de suelo se empleó la técnica nuclear del 137 Cesio (como radioisótopo trazador ambiental). A su vez, se analizó la influencia de factores e indicadores que intervienen en el proceso de pérdida de suelo: pendiente y precipitación, textura (método Bouyoucos), color (tabla Munsell), materia orgánica (digestión húmeda con dicromato de potasio), pH (método Potenciométrico) y capacidad de intercambio catiónico (acetato de amoniopH 7 1N). Los resultados obtenidos reflejan grandes pérdidas de suelo asociadas a las características fisicoquímicas de éste. Se manifiesta la urgente necesidad de implementar medidas de conservación de suelo que permitan la sustentabilidad agrícola en el sitio de estudio
Assessment of psychometric properties of the academic involvement questionnaire, expectations version
Indexación: Web of Science; Scielo.Background: Academic Involvement Questionnaire, Expectations version (CIA-A), assesses the expectations of involvement in studies. It is a relevant predictor of student success. However, the evidence of its validity and reliability in Chile is low, and in the case of Medical students, there is no evidence at all. Aim: To evaluate the factorial structure and internal consistency of the CIA-A in Chilean Medical school freshmen. Material and Methods: The survey was applied to 340 Medicine freshmen, chosen by non-probability quota sampling. They answered a back-translated version of CIA-A from Portuguese to Spanish, plus a sociodemographic questionnaire. For psychometric analysis of the CIA-A, an exploratory factor analysis was carried on, the reliability of the factors was calculated, a descriptive analysis was conducted and their correlation was assessed. Results: Five factors were identified: vocational, institutional and social involvement, use of resources and student participation. Their reliabilities ranged between Cronbach’s alpha values of 0.71 to 0.87. Factors also showed statistically significant correlations between each other. Conclusions: Identified factor structure is theoretically consistent with the structure of original version. It just disagrees in one factor. In addition, the factors’ internal consistency were adequate for using them in research. This supports the construct validity and reliability of the CIA-A to assess involvement expectations in medical school freshmen.http://ref.scielo.org/r2sn6
Global regime shift dynamics of catastrophic sea urchin overgrazing
A pronounced, widespread and persistent regime shift among marine ecosystems is observable on temperate rocky reefs as a result of sea urchin overgrazing. Here, we empirically define regime-shift dynamics for this grazing system which transitions between productive macroalgal beds and impoverished urchin barrens. Catastrophic in nature, urchin overgrazing in a well-studied Australian system demonstrates a discontinuous regime shift, which is of particular management concern as recovery of desirable macroalgal beds requires reducing grazers to well below the initial threshold of overgrazing. Generality of this regime-shift dynamic is explored across 13 rocky reef systems (spanning 11 different regions from both hemispheres) by compiling available survey data (totalling 10 901 quadrats surveyed in situ) plus experimental regime-shift responses (observed during a total of 57 in situ manipulations). The emergent and globally coherent pattern shows urchin grazing to cause a discontinuous ‘catastrophic’ regime shift, with hysteresis effect of approximately one order of magnitude in urchin biomass between critical thresholds of overgrazing and recovery. Different life-history traits appear to create asymmetry in the pace of overgrazing versus recovery. Once shifted, strong feedback mechanisms provide resilience for each alternative state thus defining the catastrophic nature of this regime shift. Importantly, human-derived stressors can act to erode resilience of desirable macroalgal beds while strengthening resilience of urchin barrens, thus exacerbating the risk, spatial extent and irreversibility of an unwanted regime shift for marine ecosystems.Peer reviewe
Transcriptomic and biochemical investigations support the role of rootstock-scion interaction in grapevine berry quality
Background In viticulture, rootstock genotype plays a critical role to improve scion physiology, berry quality and to adapt grapevine (Vitis viniferaL.) to different environmental conditions. This study aimed at investigating the effect of two different rootstocks (1103 Paulsen - P - and Mgt 101-14 - M) in comparison with not grafted plants - NGC - on transcriptome (RNA-seq and small RNA-seq) and chemical composition of berry skin inPinot noir, and exploring the influence of rootstock-scion interaction on grape quality. Berry samples, collected at veraison and maturity, were investigated at transcriptional and biochemical levels to depict the impact of rootstock on berry maturation. Results RNA- and miRNA-seq analyses highlighted that, at veraison, the transcriptomes of the berry skin are extremely similar, while variations associated with the different rootstocks become evident at maturity, suggesting a greater diversification at transcriptional level towards the end of the ripening process. In the experimental design, resembling standard agronomic growth conditions, the vines grafted on the two different rootstocks do not show a high degree of diversity. In general, the few genes differentially expressed at veraison were linked to photosynthesis, putatively because of a ripening delay in not grafted vines, while at maturity the differentially expressed genes were mainly involved in the synthesis and transport of phenylpropanoids (e.g. flavonoids), cell wall loosening, and stress response. These results were supported by some differences in berry phenolic composition detected between grafted and not grafted plants, in particular in resveratrol derivatives accumulation. Conclusions Transcriptomic and biochemical data demonstrate a stronger impact of 1103 Paulsen rootstock than Mgt 101-14 or not grafted plants on ripening processes related to the secondary metabolite accumulations in berry skin tissue. Interestingly, theMYB14gene, involved in the feedback regulation of resveratrol biosynthesis was up-regulated in 1103 Paulsen thus supporting a putative greater accumulation of stilbenes in mature berries
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