bluuebunny/crossref_metadata_2025_split huggingface dataset:
Which plant traits determine abundance under long‐term shifts in soil resource availability and grazing intensity?
Authors: Laliberté Etienne , Shipley Bill , Norton David A. , Scott David 
Published: January 2012

Summary1. Soil resource availability and disturbance are widely recognized as key drivers of plant community structure. However, the relative importance of different plant traits in determining species abundance following shifts in soil resource availability and disturbance remains little studied, particularly in long‐term experiments.2. We studied trait‐based plant community assembly in a 27‐year grassland experiment where 25 plant species were sown into resident vegetation, after which annual manipulations of soil resource availability (five levels of superphosphate fertilizer; the highest level was also irrigated) and disturbance (three ‘mob‐grazed’ sheep grazing intensity levels: lax, moderate, hard) were applied. We used community assembly through trait selection (CATS) models based on entropy maximization to predict species relative abundances and to quantify the relative importance of each trait in determining abundance.3. Plant species were primarily differentiated along a trade‐off axis corresponding to traits promoting rapid growth (e.g. high leaf [N] and specific leaf area [SLA]) vs. those promoting long leaf life span. Using 12 traits, the CATS model predicted >80% of the variation in the relative abundances of 51 species, suggesting that trait‐based filtering was important.4. Species with leaf attributes that reduce nutrient losses held a long‐term advantage under the lowest soil resource availability, whereas those associated with a rapid growth rate became dominant under soil resource addition. Species with thinner leaves were also favoured under greater soil resource availability, which may reflect a strategy to maximize SLA without sacrificing leaf density and thus maintain leaf structural defences under grazing disturbance. Greater leaf [S] and the ability to symbiotically fix atmospheric N were favoured under greater soil resource availability. Greater plant height, thinner leaves and higher leaf [N] were favoured under lower grazing intensity.5. Synthesis. Our results highlight the importance of species functional differences to understand how plant communities react to increases in soil resource availability and disturbance, two important and inseparable components of land‐use change in grasslands world‐wide.
Maintenance of tree phylogenetic diversity in a highly fragmented rain forest
Authors: Arroyo‐Rodríguez Víctor , Cavender‐Bares Jeannine , Escobar Federico , Melo Felipe P. L. , Tabarelli Marcelo , Santos Bráulio A. 
Published: January 2012

Summary1. Deforestation and forest fragmentation can drive species to local extinction, potentially changing the phylogenetic community structure and diversity of remaining assemblages. We tested this hypothesis analysing a large vegetation data set from a highly fragmented rain forest.2. We assessed 9000 trees (both saplings and adults) from 268 species in 45 rain forest patches (ranging from < 1 to 700 ha) in three landscapes with different deforestation levels (4%, 11%, and 24% forest cover) in Los Tuxtlas, Mexico. We tested whether species density (i.e. number of species per unit area) and phylogenetic structure and diversity differed among landscapes, whether they were related to patch area, and whether the relationships differed among landscapes.3. Overall, the observed differences in sapling and adult species densities across forest patches and landscapes (e.g. lower species densities in smaller patches) resulted in few and very weak changes in the phylogenetic community structure and diversity. Our results indicate that local extirpation of tree species may occur randomly or uniformly (but not in a clustered manner) throughout the phylogenetic tree, supporting the hypothesis of low phylogenetic conservatism of traits associated with vulnerability to forest fragmentation in the Neotropics.4. Synthesis. This study indicates that in highly deforested and fragmented rain forests, the local extirpation of tree species does not occur across entire lineages. These novel and hopeful findings have direct implications for the ecology and conservation of fragmented rain forests. The maintenance of phylogenetic diversity in highly fragmented landscapes suggests that ecosystem function and stability may be maintained despite the loss of a number of tree species. We argue that in this unique Neotropical region, both large and small rain forest patches are critical for conserving regional tree evolutionary history.
Ultra‐low‐volume space sprays in mosquito control: a critical review
Authors: BONDS J. A. S. 
Published: January 2012

The availability of tools to control mosquito (Diptera:Culicidae) vectors that transmit disease is often limited by a variety of economic, environmental and social issues. In emergency conditions (epidemics, hurricanes, floods etc.), the application of pesticides as space sprays (either by ground or air) is the common method of choice in order to rapidly limit adult local mosquito production in the affected area. Space spray application now employs ultra‐low‐volume technology for the control of adult mosquitoes. However, the use of space sprays often raises social and environmental concerns by the general public that is served.This review will define and illustrate modern ultra‐low‐volume technology for the purpose of application as a space spray, as well as describing the engineering controls that have been developed to minimize the environmental impact. The primary social concern is validity and efficacy of application. To address this point, the review will attempt to synthesize the global literature to address the effectiveness of space sprays to significantly impact mosquito vectors in relation to human disease.
Learning from clinical work: the roles of learning cues and credibility judgements
Authors: Watling Christopher , Driessen Erik , van der Vleuten Cees P M , Lingard Lorelei 
Published: January 2012

Medical Education 2012:

46

: 192–200Context:  How learners interpret their clinical experiences to create meaningful learning has not been well studied. We explored experiences considered by doctors to be influential in their learning in order to better understand this process.Methods:  Using a grounded theory approach, we interviewed 22 academic doctors who had been in practice for ≤ 5 years. Participants were asked to reflect on experiences they considered to have been influential during their training. Constant comparative analysis for emerging themes was conducted iteratively with data collection.Results:  A model of clinical learning emerged in which the clinical work itself is central. As they observe and participate in clinical work, learners can attend to a variety of sources of information that facilitate the interpretation of the experience and the construction of knowledge from it. These ‘learning cues’ include feedback, role models, clinical outcomes, patient or family responses, and comparisons with peers. The integration of a cue depends on the learner’s judgement of its credibility. Certain cues, such as clinical outcomes or feedback from patients, are seen as innately credible, whereas other cues, particularly feedback from supervisors, are subjected to critical judgement.Conclusions:  Learners make complex judgements regarding the credibility of information about clinical performance. Credibility judgements influence the learning that arises from the clinical experience. Further understanding of how such judgements are made could guide educators in providing credible information to learners.
Faculty staff perceptions of feedback to residents after direct observation of clinical skills
Authors: Kogan Jennifer R , Conforti Lisa N , Bernabeo Elizabeth C , Durning Steven J , Hauer Karen E , Holmboe Eric S 
Published: January 2012

Medical Education 2012:

46

: 201–215Context  Performance‐based workplace assessments are increasingly important in clinical training. Given the inaccuracy of self‐assessment, the provision of external feedback to residents about their clinical skills is necessary for the development of expertise. However, little is known about the processes used by faculty members in giving feedback to residents after observing them with patients. This study explores the factors that underpin faculty members’ decisions regarding the feedback they give to residents after directly observing them with patients and the factors that influence how feedback is delivered.Methods  In 2009, 44 general internal medicine faculty staff responsible for out‐patient resident teaching from 16 internal medicine residency programmes watched four videotaped scenarios and two live scenarios of standardised residents (SRs) with standardised patients and rated the SRs using the mini‐clinical evaluation exercise (mini‐CEX) format. Faculty staff also provided feedback to the SRs after the live encounters. After each encounter, faculty staff were individually interviewed using a semi‐structured interview. Interviews were videotaped, transcribed and analysed using grounded theory methods.Results  Two broad themes were identified in faculty members’ descriptions of the feedback process: variability in feedback techniques, and the factors that influence how faculty staff think and feel about delivering feedback. Multiple approaches to feedback delivery were observed. Faculty members’ tensions in balancing positive and negative feedback, their own perceived self‐efficacy, their perceptions of the resident’s insight, receptivity, skill and potential, the faculty member–resident relationship and contextual factors impacted the feedback process.Conclusions  The provision of feedback by faculty staff to residents after observing resident–patient interactions is a complex and dynamic process and is influenced by many factors. Understanding these cognitive and affective factors may provide insight into potential new approaches to faculty development to improve faculty staff’s feedback skills and the effectiveness of their feedback.
Defying stereotypes: the elusive search for a universal model of LysR‐type regulation
Authors: Momany Cory , Neidle Ellen L. 
Published: January 2012

SummaryLysR‐type transcriptional regulators (LTTRs) compose the largest family of homologous regulators in bacteria. Considering their prevalence, it is not surprising that LTTRs control diverse metabolic functions. Arguably, the most unexpected aspect of LTTRs is the paucity of available structural information. Solubility issues are notoriously problematic, and structural studies have only recently begun to flourish. In this issue of Molecular Microbiology, Taylor et al. (2012) present the structure of AphB, a LysR‐type regulator of virulence in Vibrio cholerae. This contribution adds significantly to the group of known full‐length atomic LTTR structures, which remains small. Importantly, this report also describes an active‐form variant. Small conformational changes in the effector‐binding domain translate to global reorganization of the DNA‐binding domain. Emerging from these results is a model of theme‐and‐variation among LTTRs rather than a unified regulatory scheme. Despite common structural folds, LTTRs exhibit differences in oligomerization, promoter recognition and communication with RNA polymerase. Such variation mirrors the diversity in sequence and function associated with members of this very large family.
Decreased myosin phosphatase target subunit 1(MYPT1) phosphorylation via attenuated rho kinase and zipper‐interacting kinase activities in edematous intestinal smooth muscle
Authors: Chu J. , Miller C. T. , Kislitsyna K. , Laine G. A. , Stewart R. H. , Cox C. S. , Uray K. S. 
Published: January 2012

AbstractBackground  Intestinal edema development after trauma resuscitation inhibits intestinal motility which results in ileus, preventing enteral feeding and compromising patient outcome. We have shown previously that decreased intestinal motility is associated with decreased smooth muscle myosin light chain (MLC) phosphorylation. The purpose of the present study was to investigate the mechanism of edema‐induced decreases in MLC in a rodent model of intestinal edema.Methods  Intestinal edema was induced by a combination of resuscitation fluid administration and mesenteric venous hypertension. Sham operated animals served as controls. Contractile activity and alterations in the regulation of MLC including the regulation of MLC kinase (MLCK) and MLC phosphatase (MLCP) were measured.Key Results  Contraction amplitude and basal tone were significantly decreased in edematous intestinal smooth muscle compared with non‐edematous tissue. Calcium sensitivity was also decreased in edematous tissue compared with non‐edematous intestinal smooth muscle. Although inhibition of MLCK decreased contractile activity significantly less in edematous tissue compared with non‐edematous tissue, MLCK activity in tissue lysates was not significantly different. Phosphorylation of MYPT was significantly lower in edematous tissue compared with non‐edematous tissue. In addition, activities of both rho kinase and zipper‐interacting kinase were significantly lower in edematous tissue.Conclusions & Inferences  We conclude from these data that interstitial intestinal edema inhibits MLC phosphorylation predominantly by decreasing inhibitory phosphorylation of the MLC targeting subunit (MYPT1) of MLC phosphatase via decreased ROCK and ZIPK activities, resulting in more MLC phosphatase activity.
Topographic and manometric characterization of the recto‐anal inhibitory reflex
Authors: Cheeney G. , Nguyen M. , Valestin J. , Rao S. S. C. 
Published: January 2012

AbstractBackground  Recto‐anal inhibitory reflex (RAIR) is an integral part of normal defecation. The physiologic characteristics of RAIR along anal length and anterior‐posterior axis are unknown. The aim of this study was to perform topographic and vector‐graphic evaluation of RAIR along anal canal using high definition manometry (HDM), and examine the role of various muscle components.Methods  Anorectal topography was assessed in 10 healthy volunteers using HDM probe with 256 sensors. Recto‐anal inhibitory reflex data were analyzed every mm along the length of anal canal for topographic, baseline, residual, and plateau pressures during five mean volumes of balloon inflation (15 cc, 40 cc, 71 cc, 101 cc, 177 cc), and in 3D by dividing anal canal into 4 × 2.1 mm grids.Key Results  Relaxation pressure progressively increases along anal canal with increasing balloon volume up to 71 cc and thereafter plateaus. In 3D, RAIR is maximally seen at the middle and upper portions of anal canal (levels 1.2–3.2 cm) and posteriorly. Peak residual pressure was seen at proximal anal canal.Conclusions & Inferences  Recto‐anal inhibitory reflex is characterized by differential anal relaxation along anterior–posterior axis, longitudinally along the length of anal canal, and it depends on the rectal distention volume. It is maximally seen at internal anal sphincter pressure zone. Multidimensional analyses indicate that external anal sphincter provides bulk of anal residual pressure. Our findings emphasize importance of sensor location and orientation; as anterior and more distal location may miss RAIR.
Plasticity of mouse enteric synapses mediated through endocannabinoid and purinergic signaling
Authors: Hons I. M. , Storr M. A. , Mackie K. , Lutz B. , Pittman Q. J. , Mawe G. M. , Sharkey K. A. 
Published: January 2012

AbstractBackground  The enteric nervous system (ENS) possesses extensive synaptic connections which integrate information and provide appropriate outputs to coordinate the activity of the gastrointestinal tract. The regulation of enteric synapses is not well understood. Cannabinoid (CB)1 receptors inhibit the release of acetylcholine (ACh) in the ENS, but their role in the synapse is not understood. We tested the hypothesis that enteric CB1 receptors provide inhibitory control of excitatory neurotransmission in the ENS.Methods  Intracellular microelectrode recordings were obtained from mouse myenteric plexus neurons. Interganglionic fibers were stimulated with a concentric stimulating electrode to elicit synaptic events on to the recorded neuron. Differences between spontaneous and evoked fast synaptic transmission was examined within preparations from CB1 deficient mice (CB1−/−) and wild‐type (WT) littermate controls.Key Results  Cannabinoid receptors were colocalized on terminals expressing the vesicular ACh transporter and the synaptic protein synaptotagmin. A greater proportion of CB1−/− neurons received spontaneous fast excitatory postsynaptic potentials than neurons from WT preparations. The CB1 agonist WIN55,212 depressed WT synapses without any effect on CB1−/− synapses. Synaptic activity in response to depolarization was markedly enhanced at CB1−/− synapses and after treatment with a CB1 antagonist in WT preparations. Activity‐dependent liberation of a retrograde purine messenger was demonstrated to facilitate synaptic transmission in CB1−/− mice.Conclusions & Inferences  Cannabinoid receptors inhibit transmitter release at enteric synapses and depress synaptic strength basally and in an activity‐dependent manner. These actions help explain accelerated intestinal transit observed in the absence of CB1 receptors.
Growth‐dependent chemical and mechanical properties of cuticular membranes from leaves of Sonneratia alba
Authors: TAKAHASHI YUKI , TSUBAKI SHUNTARO , SAKAMOTO MASAHIRO , WATANABE SHIN , AZUMA JUN‐ICHI 
Published: January 2012

ABSTRACTChemical and mechanical properties of the leaf cuticular membranes (CMs) of a mangrove, Sonneratia alba J. Smith, were analysed at various leaf development stages to evaluate their tolerance to environmental stress. Our analyses demonstrate that the CMs from leaves of S. alba at different growth stages are generally rich in wax (21.5–25.7%) and cutin (52.4–63.4%) which rapidly accumulate at the early stages of leaf growth, while cutan (4.3–10.3%) and polysaccharide (2.3–7.7%) continuously accumulate throughout growth. Immature CMs are physically weak and highly viscoelastic. However, CMs become strengthened and stiffened during leaf expansion and maturation (by factors of about 1.5 and 2.4, respectively) while their flexibility decreases (68–83% decrease). Finally, the CMs lose their strength at the senescent stage (30–43% decreasement). Correlation analysis between chemical composition and mechanical properties revealed that the cutin matrix is mainly responsible for the high viscoelastic properties of CMs, while wax, cutan and polysaccharide contributed to their elasticity. Wax also affected the strength of the CMs, whereas cutan and polysaccharide showed rigidizing effect. Rapid accumulation of wax and cutin in the CMs after bud burst followed by the mechanical supports of cutan and polysaccharide in an isolateral manner contributed to the remarkable environmental tolerance of S. alba.
DNA‐PKcs Interacts with Aire and Regulates the Expression of Toll‐Like Receptors in RAW264.7 Cells
Authors: Wu J. , Zhu W. , Fu H. , Zhang Y. , Sun J. , Yang W. , Li Y. 
Published: January 2012

AbstractThe autoimmune regulator (Aire) is a key mediator of the central tolerance for peripheral tissue self‐antigen (PTAs) and is involved in the transcriptional control of many antigens in thymic medullary epithelial cells (mTECs). However, the function of Aire in peripheral lymphoid tissues and haematopoietic cells, particularly in monocytes and macrophages, remains poorly understood. We previously found that the expression of Toll‐like receptor (TLR) 1, TLR3 and TLR8 was notably upregulated in pEGFPC1/Aire stably transfected RAW264.7 (GFP‐Aire/RAW) cells, while the expressions of other TLRs were not significantly changed. The mechanism by which Aire affects TLR1, TLR3 and TLR8 expression is not clear. Interactions with other proteins, such as DNA‐dependent protein kinase (DNA‐PK), are crucial for regulating the transcriptional activity of Aire. In this study, we found that Aire and DNA‐PK catalytic subunit (DNA‐PKcs) were co‐located in the nucleus of GFP‐Aire/RAW cells, and they interact with each other. Small interfering RNA knock‐down of DNA‐PKcs in these cells decreased the expression of TLR1, TLR3 and TLR8, but no change was observed in pEGFPC1 stably transfected RAW264.7 (GFP/RAW) cells. We did not observe any change in the expressions of other TLRs after DNA‐PKcs knock‐down in GFP‐Aire/RAW or GFP/RAW cells. A similar observation has been made in pEGFPC1/Aire or pEGFPC1 transiently transfected primary peritoneal macrophages. Using a luciferase activity assay, we found the that the transcriptional activity of TLR1, TLR3 and TLR8 promoters was also decreased after knock‐down of DNA‐PKcs in GFP‐Aire/RAW cells. In conclusion, our results suggest that DNA‐PKcs may interact with Aire to promote the expression of TLRs in RAW264.7 cells.
Cover crops of oats, stooling rye and three annual ryegrass cultivars influence maize and Cyperus esculentus growth
Authors: BEZUIDENHOUT S R , REINHARDT C F , WHITWELL M I 
Published: January 2012

Bezuidenhout SR, Reinhardt CF & Whitwell MI (2012). Cover crops of oats, stooling rye and three annual ryegrass cultivars influence maize and Cyperus esculentus growth. Weed Research 52, 153–160.SummaryNo information is available on the effect of cover crops on weed growth in maize production in KwaZulu‐Natal, South Africa. In a field experiment, the influence of two preceding cover crops, stooling rye and annual ryegrass, on the growth of maize and the weed Cyperus esculentus were compared with herbicides and weed control by hoeing. Maize emergence and early growth were delayed in the presence of physical residues of both cover crop species, especially annual ryegrass. Growth of C. esculentus was significantly inhibited in the inter‐row maize planting lines by the cover crops for the first 16 days after maize emergence, but this effect had diminished by day 28. In a pot experiment, the influence of the same two cover crops on maize and C. esculentus growth was evaluated together with oats and two additional annual ryegrass cultivars. Here, the growth of maize and C. esculentus were suppressed, especially by the root residues of the annual ryegrass, in particular the cultivar Midmar. Chemical analysis of the leachate of the root residues indicated the presence of phenolic acids and benzoxazolin‐2(3H)‐one. To achieve effective weed control, a weed management strategy combining the mulch retained on the soil surface, with a possible reduction in the type and amount of herbicide, should be implemented.