The evolution of complex and higher organisms

The evolution of Phanerozoic life has probably been influenced by extraterrestrial events and properties of the Earth-Moon system that have not, until now, been widely recognized. Tide range, gravitational strength, the Earth's axial tilt, and other planetary properties provide background conditions whose effects on evolution may be difficult to distinguish. Solar flares, asteroid impacts, supernovae, and passage of the solar system through galactic clouds can provide catastrophic changes on the Earth with consequent characteristic extinctions. Study of the fossil record and the evolution of complex Phanerozoic life can reveal evidence of past disturbances in space near the Earth. Conversely, better understanding of environmental influences caused by extraterrestrial factors and properties of the solar system can clarify aspects of evolution, and may aid in visualizing life on other planets with different properties

The relationship between body shape, body size and locomotor mode in extant lepidosaurs

Despite historic work, the mechanisms and evolutionary drivers associated with the adoption of a facultatively bipedal locomotor mode in extant lepidosaurs are unclear. Recent work has provided insights into the biomechanical triggers of bipedal locomotion, but the associated anatomies are yet to be fully understood, particularly with regard to body size across Lepidosauria. Using a dataset derived from museum specimens, representing a range of lepidosaur body shapes, we highlight the differences between obligate quadrupeds and facultative bipeds within this group and demonstrate the value of non-caudal skeletal material in identifying facultative bipeds using osteology alone. We use multiple statistical approaches to identify trends across locomotor modes relative to body size. Body size has a significant effect upon body proportions across the two locomotor modes, especially in the hindlimbs. Forelimbs lengths do not differ significantly across locomotor modes for animals of similar body size, but distal hindlimbs are significantly longer in facultative bipeds. Interestingly, femoral length does not differ across locomotor modes of a similar body size. Our findings contrast with historical tropes, and are significant for future work attempting to identify the factors driving the evolution of a facultatively bipedal locomotor mode in Lepidosauria

How might improved estimates of HIV programme outcomes influence practice? A formative study of evidence, dissemination and response

BACKGROUND: While HIV programmes have started millions of persons on life-saving antiretroviral therapy in Africa, longitudinal health information systems are frail and, therefore, data about long-term survival is often inaccurate or unknown to HIV programmes. The \u27Better Information for Health in Zambia\u27 (BetterInfo) Study - a regional sampling-based survey to assess retention and mortality in HIV programmes in Zambia - found both retention and mortality to be higher than prevailing estimates from national surveillance systems. We sought to understand how Zambian health decision-makers at different health system levels would respond to these new data, with a view to informing research translation. METHODS: We interviewed 25 purposefully sampled health decision-makers from community, facility, district, provincial and national levels. During the interviews, we shared retention and mortality estimates from both routine programme surveillance and those generated by the study. Transcripts were analysed for inductive and deductive themes, the latter drawing on Weiss\u27s framework that policy-makers interpret and apply evidence as \u27warning\u27, \u27guidance\u27, \u27reconceptualisation\u27 or \u27mobilisation of support\u27. FINDINGS: All decision-makers found study findings relevant and important. Decision-makers viewed the underestimates of mortality to be a warning about the veracity and informativeness of routine data systems. Decision-makers felt guided by the findings to improve data monitoring and, acknowledging limitations of routine data, utilised episodic patient tracing to support improved data accuracy. Findings catalysed renewed motivation and mobilisation by national level decision-makers for differentiated models of HIV care to improve patient outcomes and also improved data management systems to better capture patient outcomes. Inductive analysis highlighted a programmatic application data interpretation, in which study findings can influence facility and patient-level decision-making, quality of care and routine data management. CONCLUSIONS: New epidemiological data on patient outcomes were widely seen as informative and relevant and can potentially catalyse health system action such as using evaluations to supplement electronic medical record data to improve HIV programmes. Formative evidence suggests that targeting research dissemination at different levels of the health system will elicit different responses. Researchers supporting the translation of evidence to action should leverage all relevant levels of the health system to facilitate both policy and programmatic action

How might improved estimates of HIV programme outcomes influence practice? A formative study of evidence, dissemination and response

Background While HIV programmes have started millions of persons on life-saving antiretroviral therapy in Africa, longitudinal health information systems are frail and, therefore, data about long-term survival is often inaccurate or unknown to HIV programmes. The 'Better Information for Health in Zambia' (BetterInfo) Study - a regional sampling-based survey to assess retention and mortality in HIV programmes in Zambia - found both retention and mortality to be higher than prevailing estimates from national surveillance systems. We sought to understand how Zambian health decision-makers at different health system levels would respond to these new data, with a view to informing research translation. Methods We interviewed 25 purposefully sampled health decision-makers from community, facility, district, provincial and national levels. During the interviews, we shared retention and mortality estimates from both routine programme surveillance and those generated by the study. Transcripts were analysed for inductive and deductive themes, the latter drawing on Weiss's framework that policy-makers interpret and apply evidence as 'warning', 'guidance', 'reconceptualisation' or 'mobilisation of support'. Findings All decision-makers found study findings relevant and important. Decision-makers viewed the underestimates of mortality to be a warning about the veracity and informativeness of routine data systems. Decision-makers felt guided by the findings to improve data monitoring and, acknowledging limitations of routine data, utilised episodic patient tracing to support improved data accuracy. Findings catalysed renewed motivation and mobilisation by national level decision-makers for differentiated models of HIV care to improve patient outcomes and also improved data management systems to better capture patient outcomes. Inductive analysis highlighted a programmatic application data interpretation, in which study findings can influence facility and patient-level decision-making, quality of care and routine data management. Conclusions New epidemiological data on patient outcomes were widely seen as informative and relevant and can potentially catalyse health system action such as using evaluations to supplement electronic medical record data to improve HIV programmes. Formative evidence suggests that targeting research dissemination at different levels of the health system will elicit different responses. Researchers supporting the translation of evidence to action should leverage all relevant levels of the health system to facilitate both policy and programmatic action

It's in the loop: shared sub-surface foot kinematics in birds and other dinosaurs shed light on a new dimension of fossil track diversity

The feet of ground-dwelling birds retain many features of their dinosaurian ancestry. Experiments with living species offer insights into the complex interplay among anatomy, kinematics and substrate during the formation of Mesozoic footprints. However, a key aspect of the track-making process, sub-surface foot movement, is hindered by substrate opacity. Here, we use biplanar X-rays to image guineafowl walking through radiolucent substrates of different consistency (solid, dry granular, firm to semi-liquid muds). Despite substantial kinematic variation, the foot consistently moves in a looping pattern below ground. As the foot sinks and then withdraws, the claws of the three main toes create entry and exit paths in different locations. Sampling these paths at incremental horizons captures two-dimensional features just as fossil tracks do, allowing depth-based zones to be characterized by the presence and relative position of digit impressions. Examination of deep, penetrative tracks from the Early Jurassic confirms that bipeds had an equivalent looping response to soft substrates approximately 200 Ma. Our integration of extant and extinct evidence demonstrates the influence of substrate properties on sinking depth and sub-surface foot motion, both of which are significant sources of track variation in the fossil record of dinosaurs

Was Dinosaurian Physiology Inherited by Birds? Reconciling Slow Growth in Archaeopteryx

Archaeopteryx is the oldest and most primitive known bird (Avialae). It is believed that the growth and energetic physiology of basalmost birds such as Archaeopteryx were inherited in their entirety from non-avialan dinosaurs. This hypothesis predicts that the long bones in these birds formed using rapidly growing, well-vascularized woven tissue typical of non-avialan dinosaurs. We report that Archaeopteryx long bones are composed of nearly avascular parallel-fibered bone. This is among the slowest growing osseous tissues and is common in ectothermic reptiles. These findings dispute the hypothesis that non-avialan dinosaur growth and physiology were inherited in totality by the first birds. Examining these findings in a phylogenetic context required intensive sampling of outgroup dinosaurs and basalmost birds. Our results demonstrate the presence of a scale-dependent maniraptoran histological continuum that Archaeopteryx and other basalmost birds follow. Growth analysis for Archaeopteryx suggests that these animals showed exponential growth rates like non-avialan dinosaurs, three times slower than living precocial birds, but still within the lowermost range for all endothermic vertebrates. The unexpected histology of Archaeopteryx and other basalmost birds is actually consistent with retention of the phylogenetically earlier paravian dinosaur condition when size is considered. The first birds were simply feathered dinosaurs with respect to growth and energetic physiology. The evolution of the novel pattern in modern forms occurred later in the group's history

Profiles of HIV care disruptions among adult patients lost to follow-up in Zambia: A latent class analysis

BACKGROUND: Patients report varied barriers to HIV care across multiple domains, but specific barrier patterns may be driven by underlying, but unobserved, behavioral profiles. METHODS: We traced a probability sample of patients lost to follow-up (\u3e90 days late) as of July 31, 2015 from 64 clinics in Zambia. Among those found alive, we ascertained patient-reported reasons for care disruptions. We performed latent class analysis to identify patient subgroups with similar patterns of reasons reported and assessed the association between class membership and care status (ie, disengaged versus silently transferred to a new site). RESULTS: Among 547 patients, we identified 5 profiles of care disruptions: (1) Livelihood and Mobility (30.6% of the population) reported work/school obligations and mobility/travel as reasons for care disruptions; (2) Clinic Accessibility (28.9%) reported challenges with attending clinic; (3) Mobility and Family (21.9%) reported family obligations, mobility/travel, and transport-related reasons; (4) Doubting Need for HIV care (10.2%) reported uncertainty around HIV status or need for clinical care, and (5) Multidimensional Barriers to Care (8.3%) reported numerous (mean 5.6) reasons across multiple domains. Patient profiles were significantly associated with care status. The Doubting Need for HIV Care class were mostly disengaged (97.9%), followed by the Multidimensional Barriers to Care (62.8%), Clinic Accessibility (62.4%), Livelihood and Mobility (43.6%), and Mobility and Family (23.5%) classes. CONCLUSION: There are distinct HIV care disruption profiles that are strongly associated with patients\u27 current engagement status. Interventions targeting these unique profiles may enable more effective and tailored strategies for improving HIV treatment outcomes

Measuring Biodiversity and Extinction – Present and Past

How biodiversity is changing in our time represents a major concern for all organismal biologists. Anthropogenic changes to our planet are decreasing species diversity through the negative effects of pollution, habitat destruction, direct extirpation of species, and climate change. But major biotic changes – including those that have both increased and decreased species diversity – have happened before in Earth’s history. Biodiversity dynamics in past eras provide important context to understand ecological responses to current environmental change. The work of assessing biodiversity is woven into ecology, environmental science, conservation, paleontology, phylogenetics, evolutionary and developmental biology, and many other disciplines; yet, the absolute foundation of how we measure species diversity depends on taxonomy and systematics. The aspiration of this symposium, and complementary contributed talks, was to promote better understanding of our common goals and encourage future interdisciplinary discussion of biodiversity dynamics. The contributions in this collection of papers bring together a diverse group of speakers to confront several important themes. How can biologists best respond to the urgent need to identify and conserve diversity? How can we better communicate the nature of species across scientific disciplines? Where are the major gaps in knowledge about the diversity of living animal and plant groups, and what are the implications for understanding potential diversity loss? How can we effectively use the fossil record of past diversity and extinction to understand current biodiversity loss

Longitudinal care cascade outcomes among people eligible for antiretroviral therapy who are newly linking to care in Zambia: A multistate analysis

BACKGROUND: Retention in human immunodeficiency virus (HIV) care is dynamic, with patients frequently transitioning in and out of care. Analytical approaches (eg, survival analyses) commonly used to assess HIV care cascade outcomes fail to capture such transitions and therefore incompletely represent care outcomes over time. METHODS: We analyzed antiretroviral therapy (ART)-eligible adults newly linking to care at 64 clinics in Zambia between 1 April 2014 and 31 July 2015. We used electronic medical record data and supplemented these with updated care outcomes ascertained by tracing a multistage random sample of patients lost to follow-up (LTFU, \u3e90 days late for last appointment). We performed multistate analyses, incorporating weights from sampling, to estimate the prevalence of 9 care states over time since linkage with respect to ART initiation, retention in care, transfers, and mortality. RESULTS: In sum, 23 227 patients (58% female; median age 34 years [interquartile range 28-41]) were ART-eligible at enrollment. At 1 year, 75.2% had initiated ART and were in care: 61.8% were continuously retained, 6.1% had reengaged after LTFU, and 7.3% had transferred. Also, 10.1% were LTFU within 7 days of enrollment, and 15.2% were LTFU at 1 year (6.7% prior to ART). One year after LTFU, 51.6% of those LTFU prior to ART remained out of care compared to 30.2% of those LTFU after initiating ART. Overall, 6.9% of patients had died by 1 year with 3.0% dying prior to ART. CONCLUSION: Multistate analyses provide more complete assessments of longitudinal HIV cascade outcomes and reveal treatment gaps at distinct timepoints in care that will still need to be addressed even with universal treatment

Patient-reported reasons for stopping care or switching clinics in Zambia: A multisite, regionally representative estimate using a multistage sampling-based approach in Zambia

BACKGROUND: Understanding patient-reported reasons for lapses of retention in human immunodeficiency virus (HIV) treatment can drive improvements in the care cascade. A systematic assessment of outcomes among a random sample of patients lost to follow-up (LTFU) from 32 clinics in Zambia to understand the reasons for silent transfers and disengagement from care was undertaken. METHODS: We traced a simple random sample of LTFU patients (\u3e90 days from last scheduled visit) as determined from clinic-based electronic medical records from a probability sample of facilities. Among patients found in person, we solicited reasons for either stopping or switching care and predictors for re-engagement. We coded reasons into structural, psychosocial, and clinic-based barriers. RESULTS: Among 1751 LTFU patients traced and found alive, 31% of patients starting antiretroviral therapy (ART) between 1 July 2013 and 31 July 2015 silently transferred or were disengaged (40% male; median age, 35 years; median CD4 level, 239 cells/μL); median time on ART at LTFU was 480 days (interquartile range, 110-1295). Among the 544 patients not in care, median prevalences for patient-reported structural, psychosocial, and clinic-level barriers were 27.3%, 13.9%, and 13.4%, respectively, and were highly variable across facilities. Structural reasons, including, relocated to a new place were mostly cited among 289 patients who silently transferred (35.5%). We found that men were less likely to re-engage in care than women (odds ratio, .39; 95% confidence interval, .22-.67; P = .001). CONCLUSIONS: Efforts to improve retention of patients on ART may need to be tailored at the facility level to address patient-reported barriers