156 research outputs found
Gathering Perceptions to Strengthen Program Planning: A Citizen Science Project Highlighting Deer Impacts on Vegetation
White-tailed deer can significantly influence the composition and health of forests. University of Minnesota Extension implemented a citizen science project to help monitor the impact of deer populations on forests. Prior to design of the program, we administered a survey to potential volunteers to understand their perceptions of and knowledge about deer and their willingness to participate in our citizen science project. The survey responses helped us make informed decisions when developing our program, including decisions regarding not having a negative deer message, teaching more information about the impact of deer on vegetation, and providing both in-person and web-based resources for volunteers
Intense biogeochemical iron cycling revealed in Neoarchean micropyrites from stromatolites
International audienceIron isotope compositions of sedimentary pyrites (FeS2) are used to constrain the redox evolution of the Precambrian ocean and early Fe-based metabolisms such as Dissimilatory Iron Reduction (DIR). Sedimentary pyrites can record biotic and abiotic iron reduction, which have similar ranges of Fe isotopic fractionation, as well as post-depositional histories and metamorphic overprints that can modify Fe isotope compositions. However, some exceptionally well-preserved sedimentary records, such as the stromatolite-bearing Tumbiana Formation (ca. 2.7 Ga, Western Australia) have been proven to retain primary information on Early Neoarchean microbial ecosystems and associated metabolic pathways. Here, we present in situ Fe isotope measurements of micropyrites included in four stromatolites from the Tumbiana Formation in order to assess iron respiration metabolism using Fe isotope signatures. A set of 142 micropyrites has been analyzed in three lamina types, i.e. micritic, organic-rich and fenestral laminae, by Secondary Ion Mass Spectrometry (SIMS), using a Hyperion radio-frequency plasma source. The diversity of laminae is attributed to specific depositional environments, leading to the formation of Type 1 (micritic laminae) and Type 2 (organic-rich laminae) and early diagenetic effects (Type 3, fenestral laminae). Type 1 and 2 laminae preserved comparable δ56Fe ranges, respectively from −1.76‰ to +4.15‰ and from −1.54‰ to +4.44‰. Type 3 laminae recorded a similar range, although slightly more negative δ56Fe values between −2.20‰ and +2.65‰. Globally, our data show a large range of δ56Fe values, from −2.20‰ to +4.44‰, with a unimodal distribution that differs from the bimodal distribution previously reported in the Tumbiana stromatolites. Such a large range and unimodal distribution cannot be explained by a unique process (e.g., biotic/abiotic Fe reduction or pyrite formation only controlled by the precipitation rate). It rather could reflect a two-step iron cycling process in the sediment pore water including i) partial Fe oxidation forming Fe(OH)3 with positive δ56Fe values followed by ii) partial, possibly microbially induced, Fe reduction leading to Fe2+ availability for pyrite formation by sulfate reducers carrying both negative δ56Fe and δ34S signatures. In this model, the buildup and subsequent reduction through time of a residual Fe(OH)3 reservoir arising from the activity of methanotrophs, can explain the strongly positive δ56FeFe(OH)3 values up to 4‰. These results indicate that Archean microbial mats have been the site of the interaction of several closely linked biogeochemical cycles involving Fe, S and C
Schulinterne Aushandlung der Anforderung, Lernende partizipieren zu lassen: welche Schulentwicklungschancen entstehen?
Im Beitrag wird der Frage nachgegangen, wie Partizipation von Schülerinnen und Schülern – als Qualitätsmerkmal – in Schulen ausgehandelt wird. Vor dem Hintergrund der Praxistheorie wird die Erweiterung von Partizipationsmöglichkeiten als Anlass für Schulentwicklung thematisiert, die sich in den verschiedenen Praktiken der Schule zeigt. Mit Hilfe der Dokumentarischen Methode wurden Gruppendiskussionen mit Lehrpersonen analysiert, wobei zwei Typen anhand der Vergleichsdimension Bild der Lernenden ausgearbeitet wurden. Im Beitrag wird gezeigt, wie diese Vergleichsdimension mit dem Verständnis der eigenen Rolle der Lehrpersonen zusammenhängt und daraus unterschiedliche Räume für Partizipation für Schülerinnen und Schüler entstehen. Im Anschluss an die Analyse wird diskutiert, wie aus der Dokumentarischen Methode, mit besonderem Fokus auf das Gespräch als Teamperformanz und Praktik, Hinweise auf relevante Fragestellungen an die schulische Partizipations- und Schulentwicklungsforschung abgeleitet werden können
The relationship between blood–brain barrier dysfunction and neurocognitive impairments in first-episode psychosis: findings from a retrospective chart analysis
Background
Even before the onset of psychotic symptoms, individuals with schizophrenia display cognitive impairments. Simultaneously, increasing amounts of individuals exhibit dysfunction of the blood–brain barrier (BBB). However, the impact of BBB dysfunction on neurocognitive impairment in people with first-episode psychosis has not yet been investigated.
Aims
To advance understanding of said relationship, we considered one of the largest first-episode psychosis cohorts with cerebrospinal fluid parameters available, and investigated whether BBB dysfunction is related to working memory, working speed and attention.
Method
We conducted a retrospective chart review of 121 in-patients diagnosed with a first episode of a schizophrenia spectrum disorder. Patients underwent neurocognitive testing and a lumbar puncture within routine clinical care. To define BBB dysfunction, albumin cerebrospinal fluid/serum quotients, immunoglobulin G ratios and oligoclonal band types were evaluated, and gender-specific differences investigated. Neurocognitive functioning was assessed by the Wechsler Adult Intelligence Scale, Test of Attentional Performance and Repeatable Battery for the Assessment of Neuropsychological Status. We performed simple and multiple linear regression analyses to interpret associations of interest.
Results
Of those tested, 16% showed an alteration in albumin quotients and 12% had an oligoclonal band type indicating BBB dysfunction. Notably, male patients were more likely to have an increased albumin quotient and a higher immunoglobulin G ratio than female patients. We found no significant association between BBB dysfunction and neurocognitive assessments.
Conclusions
The hypothesised relationship between BBB and neurocognitive impairments was not detectable in our retrospective cohort. Further cerebrospinal fluid-based studies with a longitudinal assessment of cognitive functioning and disease trajectory are urgently needed
A transcriptional timetable of autumn senescence
BACKGROUND: We have developed genomic tools to allow the genus Populus (aspens and cottonwoods) to be exploited as a full-featured model for investigating fundamental aspects of tree biology. We have undertaken large-scale expressed sequence tag (EST) sequencing programs and created Populus microarrays with significant gene coverage. One of the important aspects of plant biology that cannot be studied in annual plants is the gene activity involved in the induction of autumn leaf senescence. RESULTS: On the basis of 36,354 Populus ESTs, obtained from seven cDNA libraries, we have created a DNA microarray consisting of 13,490 clones, spotted in duplicate. Of these clones, 12,376 (92%) were confirmed by resequencing and all sequences were annotated and functionally classified. Here we have used the microarray to study transcript abundance in leaves of a free-growing aspen tree (Populus tremula) in northern Sweden during natural autumn senescence. Of the 13,490 spotted clones, 3,792 represented genes with significant expression in all leaf samples from the seven studied dates. CONCLUSIONS: We observed a major shift in gene expression, coinciding with massive chlorophyll degradation, that reflected a shift from photosynthetic competence to energy generation by mitochondrial respiration, oxidation of fatty acids and nutrient mobilization. Autumn senescence had much in common with senescence in annual plants; for example many proteases were induced. We also found evidence for increased transcriptional activity before the appearance of visible signs of senescence, presumably preparing the leaf for degradation of its components
RP105 deficiency attenuates early atherosclerosis via decreased monocyte influx in a CCR2 dependent manner
AbstractObjective: Toll like receptor 4 (TLR4) plays a key role in inflammation and previously it was established that TLR4 deficiency attenuates atherosclerosis. RadioProtective 105 (RP105) is a structural homolog of TLR4 and an important regulator of TLR4 signaling, suggesting that RP105 may also be an important effector in atherosclerosis. We thus aimed to determine the role of RP105 in atherosclerotic lesion development using RP105 deficient mice on an atherosclerotic background. Methods and results: Atherosclerosis was induced in Western-type diet fed low density lipoprotein receptor deficient (LDLr−/−) and LDLr/RP105 double knockout (LDLr−/−/RP105−/−) mice by means of perivascular carotid artery collar placement. Lesion size was significantly reduced by 58% in LDLr−/−/RP105−/− mice, and moreover, plaque macrophage content was markedly reduced by 40%. In a model of acute peritonitis, monocyte influx was almost 3-fold reduced in LDLr−/−/RP105−/− mice (P = 0.001), while neutrophil influx remained unaltered, suggestive of an altered migratory capacity of monocytes upon deletion of RP105. Interestingly, in vitro stimulation of monocytes with LPS induced a downregulation of CCR2, a chemokine receptor crucially involved in monocyte influx to atherosclerotic lesions, which was more pronounced in LDLr−/−/RP105−/− monocytes as compared to LDLr−/− monocytes. Conclusion: We here show that RP105 deficiency results in reduced early atherosclerotic plaque development with a marked decrease in lesional macrophage content, which may be due to disturbed migration of RP105 deficient monocytes resulting from CCR2 downregulation
"That never would have occurred to me": a qualitative study of medical students' views of a cultural competence curriculum
BACKGROUND: The evidence is mixed regarding the efficacy of cultural competence curricula in developing learners' knowledge, attitudes and skills. More research is needed to better understand both the strengths and shortcomings of existing curricula from the perspective of learners in order to improve training. METHODS: We conducted three focus groups with medical students in their first year of clinical training to assess their perceptions of the cultural competence curriculum at a public university school of medicine. RESULTS: Students evaluated the informal curriculum as a more important source of learning about cultural competence than the formal curriculum. In terms of bias in both self and others, the cultural competence curriculum increased awareness, but was less effective in teaching specific interventional skills. Students also noted that the cultural competence curriculum did not always sufficiently help them find a balance between group-specific knowledge and respect for individual differences. Despite some concerns as to whether political correctness characterized the cultural competence curriculum, it was also seen as a way to rehumanize the medical education experience. CONCLUSION: Future research needs to pay attention to issues such as perceived relevance, stereotyping, and political correctness in developing cross-cultural training programs
Relationship of creative projects in anatomy to medical student professionalism, test performance and stress: an exploratory study
<p>Abstract</p> <p>Background</p> <p>The anatomy course offers important opportunities to develop professionalism at an early stage in medical education. It is an academically significant course that also engenders stress in some students.</p> <p>Methods</p> <p>Over a three-year period, 115 of 297 students completed creative projects. Thirty-four project completers and 47 non-completers consented to participate in the study. Projects were analyzed for professionalism themes using grounded theory. A subset of project completers and non-completers were interviewed to determine their views about the stress of anatomy and medical school, as well as the value of the creative projects. We also compared test performance of project completers and non-completers.</p> <p>Results</p> <p>Projects completed early in the course often expressed ambivalence about anatomy, whereas later projects showed more gratitude and sense of awe. Project completers tended to report greater stress than noncompleters, but stated that doing projects reduced stress and caused them to develop a richer appreciation for anatomy and medicine. Project completers performed significantly lower than non-completers on the first written exam (pre-project). Differences between groups on individual exams after both the first and second creative project were nonsignificant.</p> <p>Conclusion</p> <p>For some students, creative projects may offer a useful way of reflecting on various aspects of professionalism while helping them to manage stress.</p
Towards constraining the circumpolar nitrous oxide budget
Arctic soils and sediments are well known for their huge carbon stocks and the significant positive feedback carbon dioxide (CO2) and methane (CH4) emissions can have on climate change. However, the vast amounts of nitrogen (N) and possible emissions of the strong greenhouse gas nitrous oxide (N2O) from Arctic soils are much less considered in this context. Arctic soils have been neglected in global N2O accounting, since their N2O emissions were traditionally thought to be low due to the general N-limitation of biological processes. Recent
results suggest, however, that this assumption is unwarranted and needs to be revised. Still, although we know about the risk for increasing N2O emissions from the Arctic with warming, data are available only from a handful of sites and we are lacking any estimate on the circumarctic N2O budget even under the present climate. This presentation will introduce our plan to produce the first circumarctic N2O budget, an important baseline scenario against which changes in circumarctic N2O emissions can be observed with ongoing warming and global change. In order to estimate the first circumarctic N2O budget, we synthesize existing data and organize large-scale surveys of N2O fluxes across the Circumarctic. In our synthesis effort, we collect published and unpublished data on N2O emissions and N2O soil gas concentrations and analyze the data for driving variables and mechanisms underlying the N2O fluxes from various sites with different soil and vegetation characteristics. In addition, we organize measurement campaigns (via the INTERACT remote access program) to quantify N2O fluxes across a wide variety of Arctic sites using a network of collaborator stations with simple, standardized methods, and combine this N2O screening with GIS approaches to scale up the N2O fluxes step-wise from plot to regional and circumarctic levels. Ultimately, these data will be combined with existing data-sets and archived in a database that will be made available for process modelers in order to develop and improve the performance N2O models for permafrost soils.
N2O flux data were published in 21 articles from 16 Arctic sites. In the frame of this project, N2O flux measurements were conducted in 2018 at 18 study sites located in Russia, Scandinavia, Svalbard, Canada and Alaska. First analyses show that N2O is released from a range of environmentally distinct sites and at variable magnitudes with soil N content, soil C/N ratios, vegetation cover, water availability, and nutrient content likely playing significant roles. Ultimately, this project will not only provide a valuable input towards the first estimate of the circumarctic N2O budget but also towards understanding the controls of Arctic N2O fluxes which is necessary for future projections. There is urgent need for collaboration among partners in this effort and we would thus like to invite interested researchers to contribute with further published or unpublished data on N2O fluxes/concentrations from Arctic sites to support our synthesis effort. Scientists are also highly requested to sample additional N2O data from “their” Arctic sites with the simple methods introduced here, in order to help us filling large data gaps
- …