It is sometimes morally permissible not to help others even when doing so is overall better for you. For example, you are not morally required to take a career in medicine over a career in music, even if the former is both better for others and better for you. I argue that the permissibility of not helping in a range of cases of “compensated altruism” is explained by the existence of autonomy-based considerations. I sketch a view according to which you can have autonomy-based permissions to choose between alternatives when these alternatives differ in terms of the valuable features they instantiate. Along the way, I argue that considerations of moral autonomy do not support rejecting the plausible view that we each constantly face reasons with morally requiring strength to help (distant) strangers.

Among Biomphalaria glabrata/Schistosoma mansoni snail–trematode combinations, it appears that some parasites succeed whilst others fail to infect snails. Snails that become infected are termed susceptible hosts. Those which are not infected are traditionally determined as ‘resistant’. Here the concept of B. glabrata resistance to S. mansoni is re-examined in the light of additional observations. It is suggested that, in B. glabrata/S. mansoni, compatibility is tested independently for each individual miracidium and host, and that the success or failure of an infection does not depend on the snail susceptibility/resistance status, but on the ‘matched’ or ‘mismatched’ status of the host and parasite phenotypes.

In sub-Saharan countries, like South Africa, there is scant understanding of adolescent resilience to depression over time; the multisystemic resource combinations that support such resilience; and whether more diverse resource combinations yield better mental health dividends. In response, we conducted a longitudinal concurrent nested mixed methods study with 223 South African adolescents (mean age: 17.16 years, SD = 1.73; 64.60% girls; 81.60% Black). Using longitudinal mixture modeling, the quantitative study identified trajectories of depression and associations between trajectory membership and resource diversity. Using a draw-and-write methodology and reflexive thematic analyses, the qualitative study explored the resource diversity associated with each trajectory. Taken together, these studies identified four depression trajectories (Stable Low; Declining; Worsening; Chronic High) with varying resource diversity at baseline and over time. Resource diversity was inclusive of personal, relational, contextual, and culturally valued resources in both the Stable Low and Declining trajectories, with emphasis on relational supports. Personal resources were emphasized in the Worsening and Chronic High trajectories, and culturally valued and contextual resources de-emphasized. In summary, resource constellations characterized by within and across system diversity and cultural responsiveness are more protective and will be key to advancing sub-Saharan adolescent mental health.

As our understanding of the process of resilience has become more culturally and contextually grounded, researchers have had to seek innovative ways to account for the complex, reciprocal relationship between the many systems that influence young people’s capacity to thrive. This paper briefly traces the history of a more contextualized understanding of resilience and then reviews a social–ecological model to explain multisystemic resilience. A case study is then used to show how a multisystemic understanding of resilience can influence the design and implementation of resilience research. The Resilient Youth in Stressed Environments study is a longitudinal mixed methods investigation of adolescents and emerging adults in communities that depend on oil and gas industries in Canada and South Africa. These communities routinely experience stress at individual, family, and institutional levels from macroeconomic factors related to boom-and-bust economic cycles. Building on the project’s methods and findings, we discuss how to create better studies of resilience which are able to capture both emic and etic accounts of positive developmental processes in ways that avoid the tendency to homogenize children’s experience. Limitations to doing multisystemic resilience research are also highlighted, with special attention to the need for further innovation.

Iodine is an essential trace mineral, vital for its functions in many physiological processes in the human body. Both iodine deficiency (ID) and excess are associated with adverse health effects; ID and excess iodine intake have both been identified in sub-Saharan Africa (SSA). The review aims to (1) review the iodine status among populations in SSA until October 2018, and (2) identify populations at risk of excess or inadequate iodine intakes. A systematic search of relevant articles was carried out by a seven-member research team using PubMed, Science Direct and Scopus. A total of twenty-two articles was included for data extraction. Of the articles reviewed, the majority sought to determine the prevalence of iodine status of the study populations; others measured the impact of uncontrolled and unmonitored salt iodisation on iodine excess and tested the effectiveness of water iodisation. Although iodine status varied largely in study populations, ID and excessive iodine intake often coexisted within populations. The implementation of nutrition interventions and other strategies across SSA has resulted in the reduction of goitre prevalence. Even so, goitre prevalence remains high in many populations. Improvements in access to iodised salt and awareness of its importance are needed. The emerging problem of excess iodine intakes, however, should be taken into consideration by policy makers and programme implementers. As excessive iodine intakes may have adverse health effects greater than those induced by iodine deficient diets, more population-based studies are needed to investigate iodine intakes of the different population groups.

Cercariae, like miracidia, are non-parasitic larval stages implicated in the life cycle of all trematodes for the host-to-host parasite transmission. Almost all cercariae are free-living in the external environment. With a few exceptions (cercariae of Halipegus occidualis (Halipegidae) can live several months, Shostak & Esch, 1990a), cercariae have a short active life during which they do not feed, living on accumulated reserves. Most cercariae encyst as metacercariae in second intermediate hosts which are prey of the definitive host; in certain species, the interruption of the active life is achieved by an encystment in the external environment (or a simple immobile waiting strategy in a few species). In some two-host life cycles, the cercariae develop into adults after penetration (this is the case for various species causing human schistosomiasis). Some cercariae do not leave the mollusc which must then be ingested by the definitive host.

Milk losses associated with mastitis can be attributed to either effects of pathogens per se (i.e. direct losses) or to effects of the immune response triggered by the presence of mammary pathogens (i.e. indirect losses). Test-day milk somatic cell counts (SCC) and number of bacterial colony forming units (CFU) found in milk samples are putative measures of the level of immune response and of the bacterial load, respectively. Mediation models, in which one independent variable affects a second variable which, in turn, affects a third one, are conceivable models to estimate direct and indirect losses. Here, we evaluated the feasibility of a mediation model in which test-day SCC and milk were regressed toward bacterial CFU measured at three selected sampling dates, 1 week apart. We applied this method on cows free of clinical signs and with records on up to 3 test-days before and after the date of the first bacteriological samples. Most bacteriological cultures were negative (52.38%), others contained either staphylococci (23.08%), streptococci (9.16%), mixed bacteria (8.79%) or were contaminated (6.59%). Only losses mediated by an increase in SCC were significantly different from null. In cows with three consecutive bacteriological positive results, we estimated a decreased milk yield of 0.28 kg per day for each unit increase in log2-transformed CFU that elicited one unit increase in log2-transformed SCC. In cows with one or two bacteriological positive results, indirect milk loss was not significantly different from null although test-day milk decreased by 0.74 kg per day for each unit increase of log2-transformed SCC. These results highlight the importance of milk losses that are mediated by an increase in SCC during mammary infection and the feasibility of decomposing total milk loss into its direct and indirect components.

Within the Soom Shale Lagerstätte of South Africa (Upper Ordovician, Hirnantian), two brachiopod taxa preserve traces of organic tissue. In Trematis, presumed bands of periostracum are preserved on the flanks of the pedicle notch, and clay mineral casts of the pedicle are preserved in many specimens of Kosoidea. Both these genera are organophosphatic-shelled Linguliformea, together with a third genus identified as Plectoglossa. A fourth brachiopod taxon in the fauna belongs within the calcitic-shelled Rhynchonelliformea (Plectothyrella). Kosoidea cedarbergensis is a new species of discinoidean.