The Lithium Depletion Boundary and the Age of the Young Open Cluster IC~2391

We have obtained new photometry and intermediate resolution ($\Delta \lambda = 2.7$ \AA\ ) spectra of 19 of these objects (14.9 $\le$ $I_c$ $\le$ 17.5) in order to confirm cluster membership. We identify 15 of our targets as likely cluster members based on their $VRI$ photometry, spectral types, radial velocity, and H$\alpha$ emission strengths. Higher S/N spectra were obtained for 8 of these probable cluster members in order to measure the strength of the lithium 6708 \AA\ doublet and thus obtain an estimate of the cluster's age. One of these 8 stars has a definite lithium detection and two other (fainter) stars have possible lithium detections. A color-magnitude diagram for our program objects shows that the lithium depletion boundary in IC~2391 is at $I_c$=16.2. Using recent theoretical model predictions, we derive an age for IC~2391 of 53$\pm$5 Myr. While this is considerably older than the age most commonly attributed for this cluster ($\sim$35 Myr) this result for IC~2391 is comparable those recently derived for the Pleiades and Alpha Persei clusters and can be explained by new models for high mass stars that incorporate a modest amount of convective core overshooting.Comment: ApJ Letters, acccepte

'I found myself a despicable being!':Medical students face disturbing moral dilemmas

CONTEXT: The psychological realm of medical students` moral experiences is explored tangentially in medical education literature, often in the context of ethics or professionalism education. This study deepens our understanding by (1) investigating the nature of moral dilemmas experienced at the onset of clinical practice, (2) exploring students` emotional response to these dilemmas, and (3) examining how students perceive the influence of these dilemmas on their professional development. METHODS: This is a cross-sectional qualitative study carried out in 2017 that applied Thematic Template Analysis to individual interviews performed with last-year medical students. The interviews followed the drawing of a Rich Picture representing moral dilemmas experienced by medical students at the onset of clinical practice. RESULTS: Moral dilemmas have four intertwined dimensions. The first relates to students` struggle to prioritize, balance and apply conflicting moral values; the second comprises the clash between students` inner motivation and the external constraints that limit the moral action; the third refers to the conflict between students' current attitudes with the desired/idealized attitudes of the doctor they intend to become; the forth corresponds to weighting conflicting ethical principles during the moral decision. Students` emotional responses are intense, long-lasting, and with a remarkable residue effect, particularly when the moral decision does not align with their moral beliefs. Moral dilemmas are impactful experiences that affect the professional development of medical students and can culminate in both detachment or growth in moral courage. CONCLUSION: Moral dilemmas are memorable, complex, and emotionally intense experiences that impact the professional development of medical students. Understanding students` moral dilemmas can help educators to devise pedagogical activities to anticipate and reflect on these experiences. These activities should happen under the guidance of a non-judgmental facilitator, capable of listening and legitimating students' thoughts and feelings while providing insights to nurture their professional development

An integrated approach to historical population assessment of the great whales: case of the New Zealand southern right whale

Accurate estimation of historical abundance provides an essential baseline for judging the recovery of the great whales. This is particularly challenging for whales hunted prior to twentieth century modern whaling, as population-level catch records are often incomplete. Assessments of whale recovery using pre-modern exploitation indices are therefore rare, despite the intensive, global nature of nineteenth century whaling. Right whales (Eubalaena spp.) were particularly exploited: slow swimmers with strong fidelity to sheltered calving bays, the species made predictable and easy targets. Here, we present the first integrated population-level assessment of the whaling impact and pre-exploitation abundance of a right whale, the New Zealand southern right whale (E. australis). In this assessment, we use a Bayesian population dynamics model integrating multiple data sources: nineteenth century catches, genetic constraints on bottleneck size and individual sightings histories informing abundance and trend. Different catch allocation scenarios are explored to account for uncertainty in the population's offshore distribution. From a pre-exploitation abundance of 28 800–47 100 whales, nineteenth century hunting reduced the population to approximately 30–40 mature females between 1914 and 1926. Today, it stands at less than 12% of pre-exploitation abundance. Despite the challenges of reconstructing historical catches and population boundaries, conservation efforts of historically exploited species benefit from targets for ecological restoration

Rotational Studies of Late-Type Stars. VII. M34 (NGC 1039) and the Evolution of Angular Momentum and Activity in Young Solar-Type Stars

We analyze Keck Hires observations of rotation in F, G, and K dwarf members of the open cluster M34 (NGC 1039), which is 250 Myr old, and we compare them to the Pleiades, Hyades, and NGC 6475. The upper bound to rotation seen in M34 is about a factor of two lower than for the 100 Myr-old Pleiades, but most M34 stars are well below this upper bound, and it is the overall convergence in rotation rates that is most striking. A few K dwarfs in M34 are still rapid rotators, suggesting that they have undergone core-envelope decoupling, followed by replenishment of surface angular momentum from an internal reservoir. Our comparison of rotation in these clusters indicates that the time scale for the coupling of the envelope to the core must be close to 100 Myr if decoupling does, in fact, occur.Comment: 16 pages + 1 table + 5 figure

A New Statistical Image Analysis Approach and Its Application to Hippocampal Morphometry

In this work, we propose a novel and powerful image analysis framework for hippocampal morphometry in early mild cognitive impairment (EMCI), an early prodromal stage of Alzheimer’s disease (AD). We create a hippocampal surface atlas with subfield information, model each hippocampus using the SPHARM technique, and register it to the atlas to extract surface deformation signals. We propose a new alternative to standard random field theory (RFT) and permutation image analysis methods, Statistical Parametric Mapping (SPM) Distribution Analysis or SPM-DA, to perform statistical shape analysis and compare its performance with that of RFT methods on both simulated and real hippocampal surface data. The major strengths of our framework are twofold: (a) SPM-DA provides potentially more powerful algorithms than standard RFT methods for detecting weak signals, and (b) the framework embraces the important hippocampal subfield information for improved biological interpretation. We demonstrate the effectiveness of our method via an application to an AD cohort, where an SPM-DA method detects meaningful hippocampal shape differences in EMCI that are undetected by standard RFT methods

Keck Spectra of Pleiades Brown Dwarf Candidates and a Precise Determination of the Lithium Depletion Edge in the Pleiades

We have obtained intermediate resolution spectra of eleven candidate brown dwarf members of the Pleiades open cluster using the Keck II telescope and LRIS spectrograph. Our primary goal was to determine the location of the "lithium depletion edge" in the Pleiades and hence to derive a precise age for the cluster. All but one of our 11 program objects have radial velocities appropriate for Pleiades members, have moderately strong H alpha emission, and have spectral types M6 to M8.5, as expected for their (R-I) colors. We have constructed a color-magnitude diagram for the faint end of the Pleiades main sequence, including only stars for which high S/N spectra in the region of the lithium 6708 Angstrom absorption line have been obtained. These data allow us to accurately determine the Pleiades single-star lithium depletion edge at I(c0) = 17.80, R-I(c0) = 2.20, spectral type = M6.5. By reference to theoretical evolutionary models, this converts fairly directly into an age for the Pleiades of 125 Myr. This is significantly older than the age that is normally quoted, but does agree with some other recent estimates.Comment: 12 pages, including 3 Figures. Accepted by ApJ Letter

Understanding complex relationships between human well-being and land use change in Mozambique using a multi-scale participatory scenario planning process

The path for bringing millions of people out of poverty in Africa is likely to coincide with important changes in land use and land cover (LULC). Envisioning the different possible pathways for agricultural, economic and social development, and their implications for changes in LULC, ecosystem services and society well-being, will improve policy-making. This paper presents a case that uses a multi-scale participatory scenario planning method to facilitate the understanding of the complex interactions between LULC change and the wellbeing of the rural population and their possible future evolution in Mozambique up to 2035. Key drivers of change were identified: the empowerment of civil society, the effective application of legislation and changes in rural technologies (e.g., information and communications technologies and renewable energy sources). Three scenarios were constructed: one characterized by the government promoting large investments; a second scenario characterized by the increase in local community power and public policies to promote small and medium enterprises; and a third, intermediate scenario. All three scenarios highlight qualitative large LULC changes, either driven by large companies or by small and medium scale farmers. The scenarios have different impact in wellbeing and equity, the first one implying a higher rural to urban area migration. The results also show that the effective application of the law can produce different results, from assuring large international investments to assuring the improvement of social services like education, health care and extension services. Successful application of these policies, both for biodiversity and ecosystem services protection, and for the social services needed to improve the well-being of the Mozambican rural population, will have to overcome significant barriers

Risk for depression and neural responses to fearful facial expressions of emotion

BACKGROUND: Depression is associated with neural abnormalities in emotional processing. AIMS: This study explored whether these abnormalities underlie risk for depression. METHOD: We compared the neural responses of volunteers who were at high and low-risk for the development of depression (by virtue of high and low neuroticism scores; high-N group and low-N group respectively) during the presentation of fearful and happy faces using functional magnetic resonance imaging (fMRI). RESULTS: The high-N group demonstrated linear increases in response in the right fusiform gyrus and left middle temporal gyrus to expressions of increasing fear, whereas the low-N group demonstrated the opposite effect. The high-N group also displayed greater responses in the right amygdala, cerebellum, left middle frontal and bilateral parietal gyri to medium levels of fearful v. happy expressions. CONCLUSIONS: Risk for depression is associated with enhanced neural responses to fearful facial expressions similar to those observed in acute depression

Cost-effectiveness of psychological intervention within services for depression delivered by primary care workers in Nepal: economic evaluation of a randomized control trial

Abstract Background Integrating services for depression into primary care is key to reducing the treatment gap in low- and middle-income countries. We examined the value of providing the Healthy Activity Programme (HAP), a behavioral activation psychological intervention, within services for depression delivered by primary care workers in Chitwan, Nepal using data from the Programme for Improving Mental Health Care. Methods People diagnosed with depression were randomized to receive either standard treatment (ST), comprised of psychoeducation, antidepressant medication, and home-based follow up, or standard treatment plus psychological intervention (T + P). We estimated incremental costs and health effects of T + P compared to ST, with quality adjusted life years (QALYs) and depression symptom scores over 12 months as health effects. Nonparametric uncertainty analysis provided confidence intervals around each incremental effectiveness ratio (ICER); results are presented in 2020 international dollars. Results Sixty participants received ST and 60 received T + P. Implementation costs (ST = $329, T + P =$617) were substantially higher than service delivery costs (ST = $18.7, T + P =$22.4) per participant. ST and T + P participants accrued 46.5 and 49.4 QALYs, respectively. The ICERs for T + P relative to ST were $4422 per QALY gained (95$2484 to $9550) – slightly above the highly cost-effective threshold – and −$53.21 (95% confidence interval: −$105.8 to −$30.2) per unit change on the Patient Health Questionnaire. Conclusion Providing HAP within integrated depression services in Chitwan was cost-effective, if not highly cost-effective. Efforts to scale up integrated services in Nepal and similar contexts should consider including evidence-based psychological interventions as a part of cost-effective mental healthcare for depression