Search

We used FLAMES+GIRAFFE (Medusa mode) at the VLT to obtain moderately high resolution spectra for 30 red horizontal branch (RHB) stars, 4 RR Lyrae variables, and 17 blue horizontal branch (BHB) stars in the low-concentration, moderately metal-rich globular cluster NGC 6723 ([Fe/H] = -1.22 ± 0.08 from our present sample). The spectra were optimized to derive O and Na abundances. In addition, we obtained abundances for other elements, including N, Fe, Mg, Ca, Ni, and Ba. We used these data to discuss the evidence of a connection between the distribution of stars along the horizontal branch (HB) and the multiple populations that are typically present in globular clusters. We found that all RHB and most (13 out of 17) BHB stars are O-rich, Na-poor, and N-poor; these stars probably belong to the first stellar generation in this cluster. Only the four warmest observed stars are (moderately) O-poor, Na-rich, and N-rich, and they probably belong to the second generation. While our sample is not fully representative of the whole HB population in NGC 6723, our data suggest that in this cluster only HB stars warmer than ~9000 K, that is one fourth of the total, belong to the second generation, if at all. Since in many other clusters this fraction is about two thirds, we conclude that the fraction of first/second generation in globular clusters may be strongly variable. In addition, the wide range in colour of chemically homogeneous first-generation HB stars requires a considerable spread in mass loss (>0.10 M⊙). The reason for this spread is yet to be understood. Finally, we found a high Ba abundance, with a statistically significant radial abundance gradient. [ABSTRACT FROM AUTHOR]

Two independent studies recently uncovered two distinct populations among giants in the distant, massive globular cluster (GC) NGC 2419. One of these populations has normal magnesium (Mg) and potassium (K) abundances for halo stars: enhanced Mg and roughly solar K. The other population has extremely depleted Mg and very enhanced K. To better anchor the peculiar NGC 2419 chemical composition, we have investigated the behavior of K in a few red giant branch stars in NGC 6752, NGC 6121, NGC 1904, and ω Cen. To verify that the high K abundances are intrinsic and not due to some atmospheric features in giants, we also derived K abundances in less evolved turn-off and subgiant stars of clusters 47 Tuc, NGC 6752, NGC 6397, and NGC 7099. We normalized the K abundance as a function of the cluster metallicity using 21 field stars analyzed in a homogeneous manner. For all GCs of our sample, the stars lie in the K–Mg abundance plane on the same locus occupied by the Mg-normal population in NGC 2419 and by field stars. This holds for both giants and less-evolved stars. At present, NGC 2419 seems unique among GCs. [ABSTRACT FROM AUTHOR]

To check the impact of the multiple population scenario for globular clusters on their horizontal branch (HB), we present an analysis of the composition of 110 red HB (RHB) stars in 47 Tucanae and of 61 blue HB (BHB) and 30 RHB stars in M 5. In 47 Tuc we found tight relations between the colours of the stars and their abundances of p-capture elements. This strongly supports the idea that the He content - which is expected to be closely correlated with the abundances of p-capture elements - is the third parameter (after overall metallicity and age) that determines the colour of HB stars. However, the range in He abundance must be small (Δ?Y < 0.03) in 47 Tuc to reproduce our observations; this agrees with previous analyses. There is possibly a correlation between the abundances of p- and n-capture elements in 47 Tuc. If confirmed, this might suggest that asymptotic giant branch stars of moderate mass contributed to the gas from which second-generation stars formed. Considering the selection effects in our sample (which does not include stars warmer than 11 000 K and RR Lyrae variables, which were excluded because we could not obtain accurate abundances with the adopted observing procedure) is important to understand our results for M 5. In this case, we find that, as expected, RHB stars are Na-poor and O-rich, and likely belong to the primordial population. There is a clear correlation of the [Na/O] ratio and N abundance with colour along the BHB. A derivation of the He abundance for these stars yields a low value of Y = 0.22 ± 0.03. This is expected because HB stars of a putative He-rich population in this cluster should be warmer than 11 000 K, and would accordingly not have been sampled by our analysis. However, we need some additional source of scatter in the total mass loss of stars climbing up the red giant branch to reproduce our results for M 5. Finally, we found a C-star on the HB of 47 Tuc and a Ba-rich, fast-rotating, likely binary star on the HB of M 5. These stars are among the brightest and coolest HB stars. [ABSTRACT FROM AUTHOR]

We use Hubble Space Telescope (HST) and ground-based imaging to study the multiple populations of 47 Tucanac (47 Tuc), combining high-precision photometry with calculations of synthetic spectra. Using filters covering a wide range of wavelengths, our HST photometry splits the main sequence into two branches, and we find that this duality is repeated in the subgiant and red giant regions, and on the horizontal branch. We calculate theoretical stellar atmospheres for main-sequence stars, assuming different chemical composition mixtures, and we compare their predicted colors through the HST filters with our observed colors. We find that we can match the complex of observed colors with a pair of populations, one with primeval abundance and another with enhanced nitrogen and a small helium enhancement, but with depleted C and O. We confirm that models of red giant and red horizontal branch stars with that pair of compositions also give colors that fit our observations. We suggest that the different strengths of molecular bands of OH, CN, CH, and NH, falling in different photometric bands, are responsible for the color splits of the two populations. Near the cluster center, in each portion of the color-magnitude diagram the population with primeval abundances makes up only ~20% of the stars, a fraction that increases outward, approaching equality in the outskirts of the cluster, with a fraction ~30% averaged over the whole cluster. Thus the second, He/N-enriched population is more concentrated and contributes the majority of the present-day stellar content of the cluster. We present evidence that the color-magnitude diagram of 47 Tuc consists of intertwined sequences of the two populations, whose separate identities can be followed continuously from the main sequence up to the red giant branch, and thence to the horizontal branch. A third population is visible only in the subgiant branch, where it includes ~8% of the stars. [ABSTRACT FROM AUTHOR]

We present Li and Fe abundances for 87 stars in the globular cluster M4, obtained by using high-resolution spectra collected with GIRAFFE at the Very Large Telescope. The targets range from the turn-off up to the red giant branch bump. The Li abundance in the turn-off stars is uniform, with an average value equal to A(Li)= 2.30 ± 0.02 dex ( dex), consistent with the upper envelope of Li content measured in other globular clusters and in the halo field stars, confirming also for M4 the discrepancy with the primordial Li abundance predicted by Wilkinson Microwave Anisotropy Probe+ big bang nucleosynthesis (WMAP+BBNS). The global behaviour of A(Li) as a function of the effective temperature allows us to identify the two main drops in the Li evolution due to the first dredge-up and to the extra-mixing episode after the red giant branch bump. The measured iron content of M4 results to dex ( dex), with no systematic offsets between dwarf and giant stars. The behaviour of the Li and Fe abundances along the entire evolutionary path is incompatible with theoretical models including pure atomic diffusion, pointing out that an additional turbulent mixing below the convective region needs to be taken into account, able to inhibit the atomic diffusion. The measured value of A(Li) and its homogeneity in the turn-off stars allow us to put strong constraints on the shape of the Li profile inside the M4 turn-off stars. The global behaviour of A(Li) with the effective temperature can be reproduced with different pristine Li abundances, depending on the kind of adopted turbulent mixing. One cannot reproduce the global trend that starts from the WMAP+BBNS A(Li) and adopts the turbulent mixing described by Richard, Michaud & Richer with the same efficiency as that used by Korn et al. to explain the Li content in NGC 6397. In fact, such a solution is not able to well reproduce simultaneously the Li abundance observed in turn-off and red giant branch stars. However, the WMAP+BBNS A(Li) can be reproduced assuming a more efficient turbulent mixing able to reach deeper stellar regions where the Li is burned. We conclude that the cosmological Li discrepancy cannot be easily solved with the present, poor understanding of the turbulence in the stellar interiors, and a future effort to well understand the true nature of this non-canonical process is needed. [ABSTRACT FROM AUTHOR]

Background: Severe acquired brain injury (sABI) encompasses a range of neurological impairments. Visual dysfunction, particularly homonymous visual field defects (HVFDs) and homonymous hemianopia (HH), commonly afflicts sABI survivors, affecting their cognitive and motor rehabilitation. This study presents the FunctionaL Assessment Scale of Hemianopia (FLASH), developed to analyze the most common postural behaviors exhibited by sABI patients with hemianopia during activities of daily living. A comparison to traditional static automated perimetry for diagnosing visual field deficits (VFDs) to determine the sensitivity and specificity of the FLASH was used. Additionally, this study also aimed to assess its reliability., Methods: Fifty-six patients (25 F, 31 M, mean age 60.59 ± 14.53) with strokes in the sub-acute phase (<6 months from the onset) were assessed with both FLASH and a Humphrey Field Analyzer., Results: After removing two items found to be less reliable than others, FLASH showed high sensitivity (81%) and specificity (77%) when compared to static automated perimetry. Inter-rater reliability was also high, with an intra-class correlation coefficient of 0.954, as well as the internal consistency computed by Cronbach's alpha, equal to 0.874., Conclusion: FLASH could offer a valuable and cost-effective screening tool for VFD in sABI patients during neurorehabilitation, with potential implications for healthcare cost reduction.

Stroke survivors with right-brain damage (RBD) often present with attentional deficits such as left unilateral spatial neglect. Some patients also present with contralesional visual hemi-field deficits. A late detection of visual hemi-field deficits (VHFD) contributes to hampering neurorehabilitation and functional outcome of patients with neglect. The Brentano Illusion Test (BRIT) may be used for an early detection of VHFD during the neuropsychological assessment. In the present study, we determined the sensitivity and specificity of the BRIT for screening VHFD in patients with neglect. Sixty-four consecutive RBD patients were examined. Forty-five presented with neglect. Of these, 23 presented with VHFD (hemianopia or quadrantanopia) as detected by the Humphrey automated static visual field testing (reference standard). Consecutive patients also included 19 participants without neglect, who did not have any VHFD. The sensitivity and specificity of the BRIT for neglect patients were 78.3% (95% CI: 61.4-95.1) and 90.9 (95% CI: 78.9-100.0), respectively. Positive predictive value (PPV) was 89.6% (95% CI: 76.4-100.0); negative predictive value (NPV) 80.7% (95% CI: 65.2-96.2). No false positives in the group without neglect were identified. We conclude that the BRIT is an effective tool for clinical neuropsychologists to screen for possible VHFD in neglect patients during the neuropsychological assessment, allowing the refinement of the clinical picture in the neuropsychological report. An early detection of VHFD also allows referring the patient to standard diagnostics for a formal visual field examination, right from the first neuropsychological assessment.

Introduction: During the COVID-19 pandemic, several restrictions were imposed to limit the circulation of the infection within communities. Hospitals denied access to the family and friends of inpatients, and thus to caregivers. This observational study evaluated the impact of the physical absence of caregivers during the lockdown period due to the COVID-19 emergency on the rehabilitation of inpatients with severe acquired brain injury (sABI)., Methods: The functional outcome at discharge was measured in 25 inpatients with sABI through the Disability Rating Scale (DRS), Glasgow Outcome Scale (GOS), and Levels of Cognitive Functioning scale (LCF) after neuropsychological rehabilitation in an Adult Inpatient Neurorehabilitation Unit for Patients with sABI. Fourteen patients were directly assisted by their informal caregivers physically present in the neurorehabilitation ward. Eleven patients were indirectly supported via remote connection because during the lockdown period (from March to July 2020) caregivers could not be admitted to the rehabilitation hospital. The Caregiving Impact on Neuro-Rehabilitation Scale (CINRS) was also used to evaluate both the change since the admission and the impact of the caregiver from the perspective of the cognitive therapist. Demographic characteristics, time since injury, injury severity (duration of impaired consciousness measured by the time to follow commands), level of functioning at the beginning of the rehabilitation, and duration of the rehabilitation treatment were comparable between the groups., Results: Both groups improved after the treatment; however, the improvement was consistently greater in the group directly assisted by the caregivers. The results showed that although the caregivers ensured their virtual presence at distance, their physical absence played a role in hindering the functional outcome of the patients., Conclusions: The role of the caregiver of patients with sABI is underlined in being not only a person handing out generic aid, cares, and affection, but also an integral part of the rehabilitation process.

Background: Severe acquired brain injury (sABI) frequently causes impairment in self-awareness (ISA), leading to reduced patients' compliance to treatment, worse functional outcome, and high caregiver distress. Self-awareness (SA) is a multilevel and complex function that, as such, requires a specific and effective assessment. To date, many tools are available to evaluate the declarative, but not emergent and anticipatory levels of awareness, therefore the Self-Awareness Multilevel Assessment Scale (SAMAS) was recently proposed. The new tool proved to be useful to assess SA at different levels across all domains of functioning (motor, cognitive, psycho-behavioural, etc.) because it measures not only the declarative SA, but also emergent and anticipatory levels of SA, thus overcoming some important limits of other current assessment methods., Aim: This study evaluated the inter-rater reliability (IRR) of the SAMAS., Methods: Four professionals blind to each other evaluated 12 patients with sABI. Each patient was rated by two professionals., Results: Inter-rater reliability was moderate-to-excellent, adding evidence in support of the use of SAMAS to specifically diagnose ISA after sABI., Conclusions: The SAMAS can help to better address neurorehabilitation, as it allows assessing ISA as early as possible, at all possible levels of awareness and functional domains.

This paper questions the pertinence of the humanitarian aid localization agenda in Latin America, at least in the narrow sense embraced by the 2016 World Humanitarian Summit. Localized support has been the standard practice in the region for decades, thanks to at least two correlated factors: the Monroe Doctrine limiting intervention to the USA and regional efforts to resist such intervention. Instead, humanitarian action in the region is an example of a particular way of understating localization, mainly specialized support to specific issues, no distinction between humanitarian or development divisions, and coexistence of different response approaches, synthesizing international and local experiences that intermingle with community practices and traditions, under national government leadership. Governments, together with NGOs, civil protection, and other relevant actors from international cooperation and development, engage in crises based on a long-standing tradition of risk management at national and regional levels. Fears of abuses hidden behind the non-interference principle, human rights activism, and disaster risk management approaches to emergencies created a complex ecosystem for humanitarian localization., Competing Interests: Competing interestsThe authors declare that they have no competing interests., (© The Author(s) 2022.)