147 research outputs found

    Hydrology influences carbon flux through metabolic pathways in the hypolimnion of a Mediterranean reservoir

    Get PDF
    Global change is modifying meteorological and hydrological factors that influence the thermal regime of water bodies. These modifications can lead to longer stratification periods with enlarged hypolimnetic anoxic periods, which can promote heterotrophic anaerobic processes and alter reservoir carbon cycling. Here, we quantified aerobic and anaerobic heterotrophic processes (aerobic respiration, denitrification, iron and manganese reduction, sulfate reduction, and methanogenesis) on dissolved inorganic carbon (DIC) production in the hypolimnion of a Mediterranean reservoir (El Gergal, Spain) under two contrasting hydrological conditions: a wet year with heavy direct rainfall and frequent water inputs from upstream reservoirs, and a dry year with scarce rainfall and negligible water inputs. During the wet year, water inputs and rainfall induced low water column thermal stability and earlier turnover. By contrast, thermal stratification was longer and more stable during the dry year. During wet conditions, we observed lower DIC accumulation in the hypolimnion, mainly due to weaker sulfate reduction and methanogenesis. By contrast, longer stratification during the dry year promoted higher hypolimnetic DIC accumulation, resulting from enhanced methanogenesis and sulfate reduction, thus increasing methane emissions and impairing reservoir water quality. Aerobic respiration, denitrification and metal reduction produced a similar amount of DIC in the hypolimnion during the two studied years. All in all, biological and geochemical (calcite dissolution) processes explained most of hypolimnetic DIC accumulation during stratification regardless of the hydrological conditions, but there is still ~ 30% of hypolimnetic DIC production that cannot be explained by the processes contemplated in this study and the assumptions made.This research was funded by project Alter-C (PID2020-114024GB-C31, PID2020-114024GB-C32, PID2020-114024GB-C33) of Spanish Ministry of Science and Innovation (Spanish Research Agency, AEI). JJM-P was supported by a Spanish FPI grant (RE2018-083596). EMASESA staff provide essential technical support during field surveys. R.M. acknowledges funding from Generalitat de Catalunya through the Consolidated Research Group 2017SGR1124 and the CERCA programme. Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. Funding for open access charge: Universidad de Málaga / CBUA

    The Gulf Stream position influences the functional composition of phytoplankton in El Gergal reservoir (Spain)

    Get PDF
    The latitudinal position of the north-wall of the Gulf Stream influences the climatic conditions in the Atlantic North and Western Europe. Southerly movements of the Gulf Stream (low Gulf Stream Index values, GSI) typically induce unstable meteorological conditions in this region, while north displacements of the oceanic current (high GSI values) are associated with stable weather. In the present article we explore a seven years data set including annual GSI, meteorological records and phytoplankton community composition and abundance to demonstrate that the year-to-year changes in the position of the Gulf Stream and its influence on the prevailing weather conditions have an effect on the long-term variability of phytoplankton community in El Gergal reservoir, an ecosystem located in the Atlantic coast of Andalusia (SW Spain). Furthermore, we describe the response of each considered phytoplankton functional groups to changes in the Gulf Stream position. Thus, northerly displacements of the north-wall increased the abundance of H+S1 cyanobacteria through a non-linear function with two marked GSI thresholds. GSI and Lm dinoflagellates abundance depicted a significant positive linear correlation, while groups B + P diatoms abundance was negatively linear correlated with GSI. Groups Y cryptophytes and X1 + J chlorophytes abundance remained nearly constant for most of the studied years but developed an exponential increase at high GSI years. Implications for water quality management are pointed out.Las condiciones climáticas en la fachada Atlántica europea están influidas por las variaciones temporales en la posición latitudinal de la Corriente del Golfo en el océano Atlántico. Así, el desplazamiento hacia el Sur de la Corriente del Golfo (valores bajos del Índice de la Corriente del Golfo, GSI) induce condiciones de inestabilidad meteorológica en la Europa occidental, mientras que los desplazamientos septentrionales de la corriente oceánica (elevados valores del GSI) están asociados con mayor estabilidad meteorológica en esta región. Este artículo estudia la influencia de los cambios interanuales en la posición de la Corriente del Golfo sobre la comunidad fitoplanctónica del embalse de El Gergal, un ecosistema localizado en la costa atlántica andaluza (SW España). Para ello, a lo largo de siete años se han registrado valores anuales de GSI, información meteorológica y datos sobre la composición y biovolumen del fitoplancton. El análisis de esta información permite describir cómo las variaciones anuales en la posición de la Corriente del Golfo afectan a las condiciones meteorológicas en el área de estudio, influyendo de esta manera sobre el biovolumen de cada uno de los grupos funcionales de fitoplancton considerados. Los desplazamientos hacia el Norte de la Corriente del Golfo favorecieron el incremento del biovolumen de cianobacterias de los grupos H + S1 a través de una función no lineal con dos valores críticos de GSI bien definidos. Por su parte, se encontró una relación lineal positiva entre el GSI y el biovolumen de dinoflagelados del grupo Lm, mientras que las diatomeas de los grupos B + P se relacionaron de forma inversa con el GSI. Aunque el biovolumen de clorofitas de los grupos X1 + J y de criptofitas del grupo Y permaneció estable durante la mayor parte de los años estudiados, se registró un notable incremento del mismo en aquellos años en los que el GSI mostró sus valores más elevados. Finalmente se apuntan algunas consideraciones sobre posibles implicaciones en la gestión de la calidad del agua embalsada

    Moving beyond physical education subject knowledge to develop knowledgeable teachers of the subject

    Get PDF
    All knowledge is socially constructed, including physical education teachers’ knowledge of their subject. It is acquired from other people either formally and deliberately (e.g. by being taught) or informally and casually (e.g. by interacting with physical education teachers or playing in a sports team). The social aspects of learning appear to be particularly strong in physical education. This has implications for the development of knowledge for teaching, with trainee teachers focusing on the development of subject, and particularly content, knowledge. Focusing on subject knowledge reinforces a traditional view of physical education as it is, not as it might be to meet the needs of young people today. It is argued that attention needs to be given not only to the knowledge, skills and competencies that trainee teachers ought to develop but also to the social aspects of their learning and development and the context in which they learn. Attention also needs to be given to how the ability to think critically can be developed so that trainee teachers can become reflective practitioners able to challenge and, where appropriate, change the teaching of the subject. Only by doing this can the particularly strong socialisation which shapes the values and beliefs of physical education teachers begin to be challenged. However, as the process of developing knowledgeable teachers is ongoing it is also necessary to look beyond teacher training to continuing professional development

    Moving beyond physical education subject knowledge to develop knowledgeable teachers of the subject

    Get PDF
    All knowledge is socially constructed, including physical education teachers’ knowledge of their subject. It is acquired from other people either formally and deliberately (e.g. by being taught) or informally and casually (e.g. by interacting with physical education teachers or playing in a sports team). The social aspects of learning appear to be particularly strong in physical education. This has implications for the development of knowledge for teaching, with trainee teachers focusing on the development of subject, and particularly content, knowledge. Focusing on subject knowledge reinforces a traditional view of physical education as it is, not as it might be to meet the needs of young people today. It is argued that attention needs to be given not only to the knowledge, skills and competencies that trainee teachers ought to develop but also to the social aspects of their learning and development and the context in which they learn. Attention also needs to be given to how the ability to think critically can be developed so that trainee teachers can become reflective practitioners able to challenge and, where appropriate, change the teaching of the subject. Only by doing this can the particularly strong socialisation which shapes the values and beliefs of physical education teachers begin to be challenged. However, as the process of developing knowledgeable teachers is ongoing it is also necessary to look beyond teacher training to continuing professional development

    Reversed-phase high-performance liquid chromatography–fluorescence detection for the analysis of glutathione and its precursor γ-glutamyl cysteine in wines and model wines supplemented with oenological inactive dry yeast preparations

    Get PDF
    El pdf del artículo es la versión pre-print.A reversed-phase high-performance liquid chromatography-fluorescence detection methodology involving a pre-column derivatization procedure using 2,3-naphtalenedialdehyde in the presence of 5 and 0. 5 mM of dithiothreitol to determine total and reduced glutathione (GSH) and γ-glutamyl-cysteine (γ-glu-cys) in musts and wines has been set up and validated. The proposed method showed good linearity (R 2 >99% for reduced and total GSH, and R 2 >98% for γ-glu-cys) in synthetic wines, over a wide range of concentration (0-10 mg L -1). The limits of detection for reduced GSH in synthetic and real wines were almost the same (0. 13 and 0. 15 mg L -1, respectively) and slightly higher for γ-glu-cys (0. 24 mg L -1). The application of the method allowed knowing, for the first time, the amount of total and reduced GSH and γ-glu-cys released into synthetic wines by oenological preparations of commercial inactive dry yeast (IDY). In addition, the evolution of these three compounds during the winemaking and shelf life (0-9 months) of an industrially manufactured rosé wine supplemented with a GSH-enriched IDY showed that although GSH is effectively released from IDY, it is rapidly oxidized during alcoholic fermentation, contributing to the higher total GSH content determined in wines supplemented with GSH-enriched IDYs compared to control wines. © 2011 Springer Science+Business Media, LLC.IAO and JJRB acknowledge CAM and CSIC for their respective research grants. This work has been founded by PET2007-0134 project.Peer Reviewe

    Stres na radu i zdravlje medicinskih sestara u jedinicama intenzivne njege u Srbiji

    Get PDF
    The aim of this study was to identify and analyse professional stressors, evaluate the level of stress in nurses in Intensive Care Units (ICU), and assess the correlation between the perception of stress and psychological and somatic symptoms or diseases shown by nurses. The research, designed as a crosssectional study, was carried out in the Intensive Care Units (ICU), in health centres in Serbia. The sample population encompassed 1000 nurses. Expanded Nursing Stress Scale (ENSS) was used as the research instrument. ENSS revealed a valid metric characteristic within our sample population. Nurses from ICUs rated situations involving physical and psychological working environments as the most stressful ones, whereas situations related to social working environment were described as less stressful; however, the differences in the perception of stressfulness of these environments were minor. Socio-demographic determinants of the participants (age, marital status and education level) significantly affected the perception of stress at work. Significant differences in the perception of stressfulness of particular stress factors were observed among nurses with respect to psychological and somatic symptoms (such as headache, insomnia, fatigue, despair, lower back pain, mood swings etc.) and certain diseases (such as hypertension, myocardial infarction, stroke, diabetes mellitus etc). In view of permanent escalation of professional stressors, creating a supportive working environment is essential for positive health outcomes, prevention of job-related diseases and better protection of already ill nurses.Cilj je ovoga rada bio identifi cirati i analizirati profesionalne stresore, procijeniti razinu stresa kod medicinskih sestara u jedinicama intenzivne njege te procijeniti korelaciju između percepcije stresa i prisutnosti psiholoških i somatskih simptoma ili bolesti kod medicinskih sestara. Istraživanje je provedeno u obliku studije presjeka u Jedinicama intenzivne njege u zdravstvenim centrima u Srbiji. Uzorak se sastojao od 1000 medicinskih sestara-tehničara. Za procjenu i analizu profesionalnih stresora korišten je upitnik Expanded Nursing Stress Scale (ENSS), koji je pokazao validne metrijske karakteristike na našoj ispitanoj populaciji. Medicinske sestre u Jedinicama intenzivne njege ocijenile su situacije iz fizičkoga i psihološkoga radnog okruženja kao izrazito opterećujuće, a situacije iz socijalnoga radnog okruženja kao manje opterećujuće. Razlika u percepciji stresogenosti navedenih radnih okruženja nije bila statistički značajna. Sociodemografske determinante ispitanika (dob, bračno stanje i stupanj obrazovanja) značajno utječu na percepciju stresa na radnom mjestu. Utvrđena je statistički značajna razlika u opažanju stresogenosti pojedinih stresnih situacija na radnom mjestu između medicinskih sestara u odnosu na postojanje psihosomatskih simptoma (kao što su glavobolja, nesanica, umor, očaj, bol u leđima, česte promjene raspoloženja) ili određenih bolesti (kao što su povišena hipertenzija, infarkt miokarda, cerebrovaskularni inzult, šećerna bolest). Zbog sve izraženije prisutnosti profesionalnih stresora nužno je poduzeti određene strateške mjere kod medicinskih sestara u Jedinicama intenzivne njege. Strateške mjere podrazumijevaju unaprjeđenje psihosocijalne radne klime, što bi unaprijedilo njihovo zdravlje i spriječilo nastanak bolesti u svezi s radom, ali i omogućilo bolju zaštitu već oboljelim medicinskim sestrama

    Key signalling nodes in mammary gland development and cancer: Myc

    Get PDF
    Myc has been intensely studied since its discovery more than 25 years ago. Insight has been gained into Myc's function in normal physiology, where its role appears to be organ specific, and in cancer where many mechanisms contribute to aberrant Myc expression. Numerous signals and pathways converge on Myc, which in turn acts on a continuously growing number of identified targets, via transcriptional and nontranscriptional mechanisms. This review will concentrate on Myc as a signaling mediator in the mammary gland, discussing its regulation and function during normal development, as well as its activation and roles in breast cancer

    Declining Sleep Quality among Nurses: A Population-Based Four-Year Longitudinal Study on the Transition from Nursing Education to Working Life

    Get PDF
    Background: Several studies have established impaired sleep is a common problem among nurses. Overworked, fatigued and stressed nurses are at a higher risk of making mistakes that threaten patient safety as well as their own health. The aim of the present study was to longitudinally monitor the development of sleep quality in nurses, starting from the last semester at the university, with three subsequent annual follow-ups once the nurses had entered working life. Methodology/Principal Findings: Nationwide, longitudinal questionnaire study of nursing students and newly qualified nurses in Sweden. The results imply a continuous decline in sleep quality among nurses during the three years of follow-up, starting from their last semester of nursing education and continuing for three years into their working life. The most pronounced short-term decline in sleep quality seems to occur in the transition between student life and working life. Conclusion/Significance: This finding is important since it may affect the quality of care and the health of nurses negatively

    Determination of c-myc amplification and overexpression in breast cancer patients: evaluation of its prognostic value against c-erbB-2, cathepsin-D and clinicopathological characteristics using univariate and multivariate analysis

    Get PDF
    C-myc and c-erbB-2 amplification and/or overexpression as well as total cathepsin-D (CD) concentration have been reported to be associated with poor prognosis in breast cancer. The prognostic significance, however, remains somewhat controversial, partly because of discrepancies among the different methodologies used. We determined the amplification and overexpression of c-myc oncogene in 152 breast cancer patients and examined its prognostic value in relation to c-erbB-2 amplification and overexpression, high concentration of CD (≥ 60 pmol mg–1 protein) and standard clinicopathological prognostic factors of the disease. High CD concentration, as well as c-myc amplification and overexpression, proved to be the best of the new variables examined for prediction of early relapse (ER; before 3 years). After multivariate analysis only CD remained significant, which suggests that the prognostic power of these variables is similar. Using univariate analysis we proved that c-myc amplification and overexpression were highly significant for disease-free survival (DFS) (P = 0.0016 and P = 0.0001 respectively) and overall survival (OS) (P < 0.0001 and P = 0.0095 respectively), although by multivariate analysis c-myc overexpression was statistically significant only for DFS (P = 0.0001) and c-myc amplification only for OS (P = 0.0006). With regard to c-erbB-2, only its overexpression appeared to be significant for DFS and OS, although after multivariate analysis its prognostic power was weaker (P = 0.030 and P = 0.024 respectively). c-myc amplification and overexpression exhibited a tendency for locoregional recurrence (LRR) (P = 0.0024 and P = 0.0075 respectively), however, their prognostic value was lower after multivariate analysis and only CD remained significant. © 1999 Cancer Research Campaig
    corecore