A photodissociation region study of NGC 4038

We present a model of the photodissociation regions of NGC 4038, which is part of the Antennae galaxies. We have considered one-dimensional slabs of uniform density, all having a maximum AV = 10 mag, interacting with plane-parallel radiation. The density range in our simulations spans four orders of magnitude (100 ≤ n ≤ 106 cm−3) and the UV field strength spans more than three orders of magnitude (10 ≤ χ ≤ 104.5 multiples of the Draine field), from which we generated a grid of about 1400 simulations. We compare our results with Herschel SPIRE-FTS, CSO and ISO-LWS observations of eight CO transition lines (J = 1-0 to 8-7) and the [C I] 609 μm and [O I] 146 μm fine-structure lines. We find that the molecular and atomic emission lines trace different gas components of NGC 4038; thus, single emission models are insufficient to reproduce the observed values. In general, low-J CO transition lines correspond to either low-density regions interacting with low UV field strengths, or high-density regions interacting with high UV field strengths. Higher J CO transition lines are less dependent on the UV field strength and are fitted by gas with density n ∼ 104.5-105.2 cm− 3. We find that the observed fine-structure line ratio of [C I] 609 μm/[O I] 146 μm is reproduced by clouds subject to weaker UV fields compared to the CO lines. We make estimates of the XCO factor which relates the CO emission with the column density of molecular hydrogen, and find that it is less than the canonical Milky Way value

Remote graphic elicitation: A critical reflection on the emotional affordance and disruption management in caregiver research

This is the final version. Available from Wiley via the DOI in this record. DATA AVAILABILITY STATEMENT: The data that support the findings of this study are available from the corresponding author upon reasonable request.Graphic elicitation, an arts-based method that focuses on participant-led drawing activities, is often conducted with the researcher in situ and discussed in an interview setting, either during or after drawing. However, the COVID-19 pandemic and the subsequent lockdowns have meant that using graphic elicitation in its current form required a re-evaluation. Reflecting on a research project that undertook graphic elicitation remotely, this paper considers the emotional affordance and disruption management of the method in caregiver research. While informal caregiving may be an emotionally fraught topic for the participants, we demonstrate how graphic elicitation explores emotions and experiences with sensitivity and care. Furthermore, we show that graphic elicitation enabled us to acknowledge the pandemic but maintain focus on caregiving itself. The caregivers were responsive to the method and found it rewarding and insightful, albeit with some initial hesitancy and ingrained perceptions of arts-based outputs. Through our discussions, we show the potential for remote graphic elicitation in geography as a method to explore potentially sensitive, emotionally charged topics like caregiving.European Research Counci

Replicating the Networking, Mentoring and Venture Creation Benefits of Entrepreneurship Centres on a Shoestring: A Student-centred Approach to Entrepreneurship Education and Venture Creation

As support for both university-level entrepreneurial education and the use of experiential learning methods to foster student entrepreneurs increases, so too have the number of university-established or affiliated entrepreneurship centers. The activity at the center of this study aimed to combine experiential learning methods with assets associated with entrepreneurship centers, including venture creation, networking, and mentoring. Students were invited to participate in a competition wherein they were guided through the business creation process and pitched their ideas to investor judges who chose the winner and provided capital start-up funding and consulting. This research puts forth that university faculty at institutions without entrepreneurship centers can organize experiences to provide the benefits of entrepreneurship centers. The study used interviews to find that many of the benefits of entrepreneurship centers were able to be replicated using this method. The project is outlined, outcomes are analyzed, and the results and lessons learned are discussed

Pledging to harm:A linguistic appraisal analysis of judgment comparing realized and non-realized violent fantasies

Intent is a psychological quality that threat assessors view as a required step on a threatener’s pathway to action. Recognizing the presence of intent in threatening language is therefore crucial to determining whether a threat is credible. Nevertheless, a ‘lack of empirical guidance’ (p. 326) is available concerning how violent intent is expressed linguistically. Using the subsystem of judgment in Appraisal analysis, this study compares realized with non-realized ‘pledges to harm’, revealing occasionally counterintuitive patterns of stancetaking by both author types – for example, that the non-realized texts are both prosodically more violent and more threatening, while the realized pledges are more ethically nuanced – which may begin to shed light on which attitudinal markers reliably correlate with an author’s intention to do future harm

Chytrid epidemics may increase genetic diversity of a diatom spring-bloom

Contrary to expectation, populations of clonal organisms are often genetically highly diverse. In phytoplankton, this diversity is maintained throughout periods of high population growth (that is, blooms), even though competitive exclusion among genotypes should hypothetically lead to the dominance of a few superior genotypes. Genotype-specific parasitism may be one mechanism that helps maintain such high-genotypic diversity of clonal organisms. Here, we present a comparison of population genetic similarity by estimating the beta-dispersion among genotypes of early and peak bloom populations of the diatom Asterionella formosa for three spring-blooms under high or low parasite pressure. The Asterionella population showed greater beta-dispersion at peak bloom than early bloom in the 2 years with high parasite pressure, whereas the within group dispersion did not change under low parasite pressure. Our findings support that high prevalence parasitism can promote genetic diversification of natural populations of clonal hosts

A biophysical model of cell adhesion mediated by immunoadhesin drugs and antibodies

A promising direction in drug development is to exploit the ability of natural killer cells to kill antibody-labeled target cells. Monoclonal antibodies and drugs designed to elicit this effect typically bind cell-surface epitopes that are overexpressed on target cells but also present on other cells. Thus it is important to understand adhesion of cells by antibodies and similar molecules. We present an equilibrium model of such adhesion, incorporating heterogeneity in target cell epitope density and epitope immobility. We compare with experiments on the adhesion of Jurkat T cells to bilayers containing the relevant natural killer cell receptor, with adhesion mediated by the drug alefacept. We show that a model in which all target cell epitopes are mobile and available is inconsistent with the data, suggesting that more complex mechanisms are at work. We hypothesize that the immobile epitope fraction may change with cell adhesion, and we find that such a model is more consistent with the data. We also quantitatively describe the parameter space in which binding occurs. Our results point toward mechanisms relating epitope immobility to cell adhesion and offer insight into the activity of an important class of drugs.Comment: 13 pages, 5 figure

Accuracy of Malaria Rapid Diagnostic Tests in Community Studies and their Impact on Treatment of Malaria in an Area with Declining Malaria Burden in North-Eastern Tanzania.

Despite some problems related to accuracy and applicability of malaria rapid diagnostic tests (RDTs), they are currently the best option in areas with limited laboratory services for improving case management through parasitological diagnosis and reducing over-treatment. This study was conducted in areas with declining malaria burden to assess; 1) the accuracy of RDTs when used at different community settings, 2) the impact of using RDTs on anti-malarial dispensing by community-owned resource persons (CORPs) and 3) adherence of CORPs to treatment guidelines by providing treatment based on RDT results. Data were obtained from: 1) a longitudinal study of passive case detection of fevers using CORPs in six villages in Korogwe; and 2) cross-sectional surveys (CSS) in six villages of Korogwe and Muheza districts, north-eastern, Tanzania. Performance of RDTs was compared with microscopy as a gold standard, and factors affecting their accuracy were explored using a multivariate logistic regression model. Overall sensitivity and specificity of RDTs in the longitudinal study (of 23,793 febrile cases; 18,154 with microscopy and RDTs results) were 88.6% and 88.2%, respectively. In the CSS, the sensitivity was significantly lower (63.4%; χ2=367.7, p<0.001), while the specificity was significantly higher (94.3%; χ2=143.1, p<0.001) when compared to the longitudinal study. As determinants of sensitivity of RDTs in both studies, parasite density of<200 asexual parasites/μl was significantly associated with high risk of false negative RDTs (OR≥16.60, p<0.001), while the risk of false negative test was significantly lower among cases with fever (axillary temperature ≥37.5 °C) (OR≤0.63, p≤0.027). The risk of false positive RDT (as a determinant of specificity) was significantly higher in cases with fever compared to afebrile cases (OR≥2.40, p<0.001). Using RDTs reduced anti-malarials dispensing from 98.9% to 32.1% in cases aged ≥5 years. Although RDTs had low sensitivity and specificity, which varied widely depending on fever and parasite density, using RDTs reduced over-treatment with anti-malarials significantly. Thus, with declining malaria prevalence, RDTs will potentially identify majority of febrile cases with parasites and lead to improved management of malaria and non-malaria fevers

Digestive Proteolytic Activity in the Sunn Pest, Eurygaster integriceps

The Sunn pest, Eurygaster integriceps Puton (Heteroptera: Scutelleridae), is one of the most important pests of wheat and causes considerable damage to this valuable crop annually. Digestive proteinase activity of adult insects was investigated using general and specific substrates and inhibitors. Proteolytic activity was low when the common conventional substrates, azoalbumin, azocasein and hemoglobin were used to assay salivary glands and midguts. Using the fluorescent casein substrate (BODIPY FL casein), total proteolytic activity was measured at different pH. Maximum proteolytic activity was detected at pH 7 (100%) and 8(65%) which suggested the presence of serine proteinases in the salivary glands. There was no detectable proteolytic activity in midgut extracts. The inhibitors; PMSF (inhibitor of serine proteinases) and TPCK (a specific chymotrypsin inhibitor) showed greater than 50% inhibitory effect on total proteolytic activity, however, TLCK (specific trypsin inhibitor) and E-64(specific cysteine proteinase inhibitor) did not inhibit total proteolytic activity. Using fluorescent specific substrates for serine and cysteine proteinases (Z-Arg-AMC, Z-Arg-Arg-AMC, Z-Arg-Phe-AMC and Suc-Ala-Ala-Pro-Phe-AMZ) revealed the presence of tryptic and chymotryptic activity in the salivary gland extract. Zymogram analysis under non-reducing SDS-PAGE conditions and using the substrate APNE showed at least 8 tryptic and chymotryptic activity bands in salivary gland extracts. A single high molecular weight band with tryptic activity (165 kDa) was detected using the substrate BApNA in a zymogram analysis uisng native-PAGE. Kinetic studies showed a km value of 0.6 mM for this enzyme against the substrate BApNA .The inhibitor TLCK decreased activity of the trypsin-like enzyme up to 73% and almost completely eliminated the only band related to this proteinase in the zymogram. Soybean Kunitz type trypsin inhibitor showed no effect on proteolytic activity of the trypsin-like serine proteinase. In general, the results revealed the presence of chymotrypsin- and trypsin-like serine proteinases in the salivary gland of E. integriceps, and it seems that the major total proteolytic activity is due to chymotrypsin proteinases

Rmi1 stimulates decatenation of double Holliday junctions during dissolution by Sgs1-Top3

double Holliday junction (dHJ) is a central intermediate of homologous recombination that can be processed to yield crossover or non-crossover recombination products. To preserve genomic integrity, cells possess mechanisms to avoid crossing over. We show that Saccharomyces cerevisiae Sgs1 and Top3 proteins are sufficient to migrate and disentangle a dHJ to produce exclusively non-crossover recombination products, in a reaction termed "dissolution." We show that Rmi1 stimulates dHJ dissolution at low Sgs1-Top3 protein concentrations, although it has no effect on the initial rate of Holliday junction (HJ) migration. Rmi1 serves to stimulate DNA decatenation, removing the last linkages between the repaired and template DNA molecules. Dissolution of a dHJ is a highly efficient and concerted alternative to nucleolytic resolution that prevents crossing over of chromosomes during recombinational DNA repair in mitotic cells and thereby contributes to genomic integrity

Can spacetime curvature induced corrections to Lamb shift be observable?

The Lamb shift results from the coupling of an atom to vacuum fluctuations of quantum fields, so corrections are expected to arise when the spacetime is curved since the vacuum fluctuations are modified by the presence of spacetime curvature. Here, we calculate the curvature-induced correction to the Lamb shift outside a spherically symmetric object and demonstrate that this correction can be remarkably significant outside a compact massive astrophysical body. For instance, for a neutron star or a stellar mass black hole, the correction is $\sim$ 25% at a radial distance of $4GM/c^2$, $\sim$ 16% at $10GM/c^2$ and as large as $\sim$ 1.6% even at $100GM/c^2$, where $M$ is the mass of the object, $G$ the Newtonian constant, and $c$ the speed of light. In principle, we can look at the spectra from a distant compact super-massive body to find such corrections. Therefore, our results suggest a possible way of detecting fundamental quantum effects in astronomical observations.Comment: 13 pages, 3 figures, slight title change, clarifications and more discussions added, version to be published in JHE