614 research outputs found

    Integrating effects of species composition and soil properties to predict shifts in montane forest carbon-water relations.

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    This study was designed to address a major source of uncertainty pertaining to coupled carbon-water cycles in montane forest ecosystems. The Sierra Nevada of California was used as a model system to investigate connections between the physiological performance of trees and landscape patterns of forest carbon and water use. The intrinsic water-use efficiency (iWUE)-an index of CO2 fixed per unit of potential water lost via transpiration-of nine dominant species was determined in replicated transects along an ∼1,500-m elevation gradient, spanning a broad range of climatic conditions and soils derived from three different parent materials. Stable isotope ratios of carbon and oxygen measured at the leaf level were combined with field-based and remotely sensed metrics of stand productivity, revealing that variation in iWUE depends primarily on leaf traits (∼24% of the variability), followed by stand productivity (∼16% of the variability), climatic regime (∼13% of the variability), and soil development (∼12% of the variability). Significant interactions between species composition and soil properties proved useful to predict changes in forest carbon-water relations. On the basis of observed shifts in tree species composition, ongoing since the 1950s and intensified in recent years, an increase in water loss through transpiration (ranging from 10 to 60% depending on parent material) is now expected in mixed conifer forests throughout the region

    Characterising food insecurity in pastoral and agro-pastoral communities in Uganda using a consumption coping strategy index

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    We explore the utility of a consumption coping strategy index (CSI) in characterising and assessing the factors influencing household food insecurity. We assessed 53 pastoral and 197 agro-pastoral households in Nakasongola and Nakaseke districts of Uganda, examining the use of 27 consumption coping strategies over a recall time of two 30-day periods, one at the start of a dry season in 2012 and one at the start of a rainy season in 2013. Four categorical food insecurity status measures were established - food secure (CSI 0 to 5) and mildly (CSI 6 to 20), moderately (CSI 21 to 42) and extremely (CSI >42) food insecure. For the dry season, the mean CSI was 29.4 ± 2.59 and 33.6 % of households were food secure, while for the rains, mean CSI was 33.1 ± 2.30 and 14.0 % of households were food secure. The combination of livelihood system, land holdings, number of livestock owned and belonging to a social network explained 9.4 % to 10 % of the variance in household food insecurity for agro-pastoralists, but variance for pastoralists was not explained by these factors. While the only highly significant factor associated with increasing household food insecurity in the dry season was low landholdings, in the rainy season, it was pastoral livelihood, low livestock holdings for agro-pastoralists and non-involvement in social networks. While our model identified a number of factors important in describing household food insecurity, it explained only about 10 % of the variance

    Novel cyclic di-GMP effectors of the YajQ protein family control bacterial virulence

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    Bis-(3 ',5 ') cyclic di-guanylate (cyclic di-GMP) is a key bacterial second messenger that is implicated in the regulation of many critical processes that include motility, biofilm formation and virulence. Cyclic di-GMP influences diverse functions through interaction with a range of effectors. Our knowledge of these effectors and their different regulatory actions is far from complete, however. Here we have used an affinity pull-down assay using cyclic di-GMP-coupled magnetic beads to identify cyclic di-GMP binding proteins in the plant pathogen Xanthomonas campestris pv. campestris (Xcc). This analysis identified XC_3703, a protein of the YajQ family, as a potential cyclic di-GMP receptor. Isothermal titration calorimetry showed that the purified XC_3703 protein bound cyclic di-GMP with a high affinity (K-d similar to 2 mu M). Mutation of XC_3703 led to reduced virulence of Xcc to plants and alteration in biofilm formation. Yeast two-hybrid and far-western analyses showed that XC_3703 was able to interact with XC_2801, a transcription factor of the LysR family. Mutation of XC_2801 and XC_3703 had partially overlapping effects on the transcriptome of Xcc, and both affected virulence. Electromobility shift assays showed that XC_3703 positively affected the binding of XC_2801 to the promoters of target virulence genes, an effect that was reversed by cyclic di-GMP. Genetic and functional analysis of YajQ family members from the human pathogens Pseudomonas aeruginosa and Stenotrophomonas maltophilia showed that they also specifically bound cyclic di-GMP and contributed to virulence in model systems. The findings thus identify a new class of cyclic di-GMP effector that regulates bacterial virulence

    ANKRD26 and Its Interacting Partners TRIO, GPS2, HMMR and DIPA Regulate Adipogenesis in 3T3-L1 Cells

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    Partial inactivation of the Ankyrin repeat domain 26 (Ankrd26) gene causes obesity and diabetes in mice and increases spontaneous and induced adipogenesis in mouse embryonic fibroblasts. However, it is not yet known how the Ankrd26 protein carries out its biological functions. We identified by yeast two-hybrid and immunoprecipitation assays the triple functional domain protein (TRIO), the G protein pathway suppressor 2 (GPS2), the delta-interacting protein A (DIPA) and the hyaluronan-mediated motility receptor (HMMR) as ANKRD26 interacting partners. Adipogenesis of 3T3-L1 cells was increased by selective down-regulation of Ankrd26, Trio, Gps2, Hmmr and Dipa. Furthermore, GPS2 and DIPA, which are normally located in the nucleus, were translocated to the cytoplasm, when the C-terminus of ANKRD26 was introduced into these cells. These findings provide biochemical evidence that ANKRD26, TRIO, GPS2 and HMMR are novel and important regulators of adipogenisis and identify new targets for the modulation of adipogenesis

    The Effect of Aliphatic Carboxylic Acids on Olfaction-Based Host-Seeking of the Malaria Mosquito Anopheles gambiae sensu stricto

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    The role of aliphatic carboxylic acids in host-seeking response of the malaria mosquito Anopheles gambiae sensu stricto was examined both in a dual-choice olfactometer and with indoor traps. A basic attractive blend of ammonia + lactic acid served as internal standard odor. Single carboxylic acids were tested in a tripartite blend with ammonia + lactic acid. Four different airflow stream rates (0.5, 5, 50, and 100 ml/min) carrying the compounds were tested for their effect on trap entry response in the olfactometer. In the olfactometer, propanoic acid, butanoic acid, 3-methylbutanoic acid, pentanoic acid, heptanoic acid, octanoic acid, and tetradecanoic acid increased attraction relative to the basic blend. While several carboxylic acids were attractive only at one or two flow rates, tetradecanoic acid was attractive at all flow rates tested. Heptanoic acid was attractive at the lowest flow rate (0.5 ml/min), but repellent at 5 and 50 ml/min. Mixing the air stream laden with these 7 carboxylic acids together with the headspace of the basic blend increased attraction in two quantitative compositions. Subtraction of single acids from the most attractive blend revealed that 3-methylbutanoic acid had a negative effect on trap entry response. In the absence of tetradecanoic acid, the blend was repellent. In assays with MM-X traps, both a blend of 7 carboxylic acids + ammonia + lactic acid (all applied from low density polyethylene-sachets) and a simple blend of ammonia + lactic acid + tetradecanoic acid were attractive. The results show that carboxylic acids play an essential role in the host-seeking behavior of An. gambiae, and that the contribution to blend attractiveness depends on the specific compound studied

    Motivations, experiences and aspirations of trainee nursing associates in England: a qualitative study

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    Background The nursing associate role was developed in England in response to the ‘Shape of Caring’ review. It has been implemented to fulfil two aims; to bridge the gap between registered nurses and healthcare assistants, and to provide an alternative route into registered nursing in light of workforce shortages. Other high income countries deploy second level nurses within their healthcare systems, however the UK has a turbulent history with such roles. The previous state enrolled nurse was phased out in the 1990s, and more recently the assistant practitioner (AP) role has faced wide variation in titles, scope and pay. Little is known about those who have embarked on the new nursing associate training course and their experiences of the role. Methods An exploratory qualitative study was undertaken using focus groups of trainee nursing associates to generate in-depth discussion about their motivations, experiences of training, and career aspirations. Three focus groups (n = 15) took place in December 2018 using a purposive sample of trainee nursing associates registered at a University in the North of England. Two researchers facilitated each group discussion at a time and place convenient for participants. The discussions were audio recorded, transcribed and data was analysed thematically. Results This study found that trainee nursing associates are motivated by affordable, local, career development. During training they face challenges relating to clinical support, academic workload and uncertainty about future career opportunities. They experience role ambiguity both individually and across the wider organisation. Trainee nursing associates rely on broad support networks to build their occupational identity. Conclusions The barriers and facilitators of trainee nursing associate personal development have implications for policy and practice relating to recruitment and retention. The results increase our understanding of this emerging role, and have informed the development of a larger longitudinal cohort study. Further research is required to evaluate the impact of this new role

    The food security continuum: a novel tool for understanding food insecurity as a range of experiences

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    The current lack of consensus on the relationships between hunger, malnutrition and food insecurity frustrates efforts to design good policies and programs to deal with the many problems. Disputes over terminology distract from the need for urgent action. This paper argues that our understanding of food insecurity is incremental: it develops as new research in a variety of food-deprived and nutrition-deprived contexts reveals causes, experiences and consequences and how they are interlinked. If we are to improve beneficiary selection, program targeting and intervention impact assessment, it is vital to coordinate our new understandings. The paper brings convergence to our understanding of food insecurity by introducing a new framework that visualizes levels of food insecurity, and the concomitant consequences and responses, as a continuum. Some potential benefits of using the continuum as a diagnostic tool are increased focus on less extreme but nevertheless urgent manifestations of food insecurity, more accurate targeting of interventions and better follow- up, and improved accountability for donor spending.http://link.springer.com/journal/12571hb201

    Relation of hypoxia inducible factor 1α and 2α in operable non-small cell lung cancer to angiogenic/molecular profile of tumours and survival

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    Hypoxia inducible factors HIF1α and HIF2α are important proteins involved in the regulation of the transcription of a variety of genes related to erythropoiesis, glycolysis and angiogenesis. Hypoxic stimulation results in rapid increase of the HIF1α and 2α protein levels, as a consequence of a redox-sensitive stabilization. The HIFαs enter the nucleus, heterodimerize with the HIF1β protein, and bind to DNA at the hypoxia response elements (HREs) of target genes. In this study we evaluated the immunohistochemical expression of these proteins in 108 tissue samples from non-small-cell lung cancer (NSCLC) and in normal lung tissues. Both proteins showed a mixed cytoplasmic/nuclear pattern of expression in cancer cells, tumoural vessels and tumour-infiltrating macrophages, as well as in areas of metaplasia, while normal lung components showed negative or very weak cytoplasmic staining. Positive HIF1α and HIF2α expression was noted in 68/108 (62%) and in 54/108 (50%) of cases respectively. Correlation analysis of HIF2α expression with HIF1α expression showed a significant association (P < 0.0001, r = 0.44). A strong association of the expression of both proteins with the angiogenic factors VEGF (P < 0.004), PD-ECGF (P < 0.003) and bFGF (P < 0.04) was noted. HIF1α correlated with the expression of bek-bFGF receptor expression (P = 0.01), while HIF2α was associated with intense VEGF/KDR-activated vascularization (P = 0.002). HIF2α protein was less frequently expressed in cases with a medium microvessel density (MVD); a high rate of expression was noted in cases with both low and high MVD (P = 0.006). Analysis of overall survival showed that HIF2α expression was related to poor outcome (P = 0.008), even in the group of patients with low MVD (P = 0.009). HIF1α expression was marginally associated with poor prognosis (P = 0.08). In multivariate analysis HIF2α expression was an independent prognostic indicator (P = 0.006, t-ratio 2.7). We conclude that HIF1α and HIF2α overexpression is a common event in NSCLC, which is related to the up-regulation of various angiogenic factors and with poor prognosis. Targeting the HIF pathway may prove of importance in the treatment of NSCLC. © 2001 Cancer Research Campaignhttp://www.bjcancer.co

    Stress and subjective well-being among first year UK undergraduate students

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    Transition to university is stressful and successful adjustment is imperative for well-being. Historically research on transitional stress focussed on negative outcomes and ill health. This is the first UK study applying a positive psychology approach to investigate the characteristics that facilitate adjustment among new university students. A range of psychological strengths conceptualised as covitality factors, shown individually to influence the stress and subjective well-being (SWB) relationship were assessed among 192 first year UK undergraduates in week three of their first semester and again six months later. Path analyses revealed that optimism mediated the relationship between stress and negative affect (a component of SWB) over time, and academic self-efficacy demonstrated significant relationships with life satisfaction and positive affect. Contrary to predictions, stress levels remained stable over time although academic alienation increased and self-efficacy decreased. Optimism emerged as a key factor for new students to adjust to university, helping to buffer the impact of stress on well-being throughout the academic year. Incorporating stress management and psycho-educational interventions to develop strengths is discussed as a way of promoting confidence and agency in new students to help them cope better with the stress at university

    Peer navigation improves diagnostic follow-up after breast cancer screening among Korean American women: results of a randomized trial

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    To test an intervention to increase adherence to diagnostic follow-up tests among Asian American women. Korean American women who were referred for a diagnostic follow-up test (mainly diagnostic mammograms) and who had missed their follow-up appointment were eligible to participate in the study. Women from two clinics (n&nbsp;=&nbsp;176) were randomly allocated to a usual care control arm or a peer navigator intervention arm. A 20-min telephone survey was administered to women in both study arms six&nbsp;months after they were identified to assess demographic and socio-economic characteristics and the primary outcome, self-reported completion of the recommended follow-up exam. Among women who completed the survey at six-month follow-up, self-reported completion of follow-up procedures was 97% in the intervention arm and 67% in the control arm (p&nbsp;&lt;&nbsp;0.001). Based on an intent-to-treat analysis of all women who were randomized and an assumption of no completion of follow-up exam for women with missing outcome data, self-reported completion of follow-up was 61% in the intervention arm and 46% in the usual care control arm (p&nbsp;&lt;&nbsp;0.069). Our results suggest that a peer navigator intervention to assist Korean American women to obtain follow-up diagnostic tests after an abnormal breast cancer screening test is efficacious
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