Reconstructing river flows remotely on Earth, Titan, and Mars.

Alluvial rivers are conveyor belts of fluid and sediment that provide a record of upstream climate and erosion on Earth, Titan, and Mars. However, many of Earth's rivers remain unsurveyed, Titan's rivers are not well resolved by current spacecraft data, and Mars' rivers are no longer active, hindering reconstructions of planetary surface conditions. To overcome these problems, we use dimensionless hydraulic geometry relations-scaling laws that relate river channel dimensions to flow and sediment transport rates-to calculate in-channel conditions using only remote sensing measurements of channel width and slope. On Earth, this offers a way to predict flow and sediment flux in rivers that lack field measurements and shows that the distinct dynamics of bedload-dominated, suspended load-dominated, and bedrock rivers give rise to distinct channel characteristics. On Mars, this approach not only predicts grain sizes at Gale Crater and Jezero Crater that overlap with those measured by the Curiosity and Perseverance rovers, it enables reconstructions of past flow conditions that are consistent with proposed long-lived hydrologic activity at both craters. On Titan, our predicted sediment fluxes to the coast of Ontario Lacus could build the lake's river delta in as little as ~1,000 y, and our scaling relationships suggest that Titan's rivers may be wider, slope more gently, and transport sediment at lower flows than rivers on Earth or Mars. Our approach provides a template for predicting channel properties remotely for alluvial rivers across Earth, along with interpreting spacecraft observations of rivers on Titan and Mars.

The Africa Temporal Scalp Flap: A Novel Flap for Facial Reconstruction.

Although a number of flaps exist for nasal reconstruction, severe scarring of the forehead after burn injury led to the development of a novel two-stage flap based on the superficial temporal artery. The Africa Temporal Scalp (ATS) flap is composed of an axial ascending part on the superficial temporal artery, and a descending anterior extension for reconstruction of the midface. This is a retrospective analysis of all patients who underwent ATS flap surgery on the MV Africa Mercy. During the 7.5-year period, the ATS flap was applied to 45 facial reconstructions, with a median age of 28 years (range 19 months to 51 years). The main indications were previous burn injury (n = 27, 60%) and noma (n = 15, 33.3%). The majority of the flaps were used to reconstruct the lower third of the nose (n = 39, 86.7%), and the remaining six were for the lips or cheek. Experience allowed for earlier division than 3 weeks depending on the length of the flap, and the recipient site. There was one partial flap loss, one infection requiring revision, and two injuries to frontal branch of the facial nerve. The ATS flap is a novel two-stage flap that has proved especially versatile when forehead flaps are unavailable for nasal reconstruction due to extensive forehead scarring. The ATS flap reliably provides ample supple skin, and the donor site is effectively obscured from view, located in the periphery of the face.

The influence of riparian woody vegetation on bankfull alluvial river morphodynamics.

Exploring the effects of bank vegetation on fluvial morphodynamics has long been an essential part of fluvial morphodynamic-related research. In a practical sense, a central question is: does increased vegetation density increase or decrease the channel width? Several aspects concerning the role of vegetation may result in examples of both width decrease and increase. In this study, we examined more than 170 alluvial river sections. Our goal was to detect the phenomena that ultimately determine riparian woody vegetation-induced width variation. We found that bed material is a governing factor. In the case of fine-grained material, i.e. median size D50 < 2 mm, increasingly densely forested riparian vegetation reduces the bankfull Shields number, and destabilizes the banks toward a wider bankfull channel. In the case of coarse-grained material (i.e. median size D50 ≥ 16 mm), the effect is the opposite; increased density is correlated with a higher bankfull Shields number and a narrower bankfull channel. The extent of the role of vegetation varies depending on the ratio of characteristic root zone depth to channel depth and channel width. We present an improved estimator for bankfull Shields number, which considers riparian vegetation density. The bankfull Shields number can be estimated up to 19% more accurately with our corrected estimator.

The Anatomical Subunit Approach to Managing Tessier Numbers 3 and 4 Craniofacial Clefts.

Patients with atypical facial clefts are rare, and there is a paucity of literature outlining the surgical approach to managing these patients. The anatomical subunit approach to the surgical correction of the cleft lip has revolutionized cleft care. Here, we outline our approach and operative technique to treating Tessier clefts 3 and 4 using a novel technique based on the anatomical subunit approach. Methods: All cases of Tessier facial clefts 3 and 4 between 2019 and 2021 from the senior author's practice were reviewed retrospectively. Patient demographics, clinical presentation, procedure details, and complications are reported. The senior author's technique is described in detail. Results: Five patients underwent treatment by the senior author during the study period. One patient had bilateral Tessier 4 clefts, one patient had bilateral Tessier 3 clefts, two patients had a unilateral Tessier 4 cleft, and one patient had a unilateral Tessier 3 cleft. Two of the patients had their clefts treated as secondary procedures. The surgical complication profile was a lost nasal stent in one patient. Treatment principles of the senior author's technique are presented. Conclusions: The anatomical subunit approach to managing atypical facial clefts provides a structured approach to a complex problem for the cleft and craniofacial surgeon. The technique of repair presented here can assist surgeons attempting to treat patients with Tessier 3 and 4 clefts.

Poyang and Dongting Lakes, Yangtze River: tributary lakes blocked by main-stem aggradation.

During its 6,300-km course from the Tibetan Plateau to the ocean, the Yangtze River is joined by two large lakes: Dongting Lake and Poyang Lake. We explain why these lakes exist. Deglaciation forced the ocean adjacent to the Yangtze mouth to rise ∼120 m. This forced a wave of rising water surface elevation and concomitant bed aggradation upstream. While aggradation attenuated upstream, the low bed slope of the Middle-Lower Yangtze River (∼2 × 10-5 near Wuhan) made it susceptible to sea level rise. The main stem, sourced at 5,054 m above sea level, had a substantial sediment load to "fight" against water surface level rise by means of bed aggradation. The tributaries of the Middle-Lower Yangtze have reliefs of approximately hundreds of meters, and did not have enough sediment supply to fill the tributary accommodation space created by main-stem aggradation. We show that the resulting tributary blockage likely gave rise to the lakes. We justify this using field data and numerical modeling, and derive a dimensionless number capturing the critical rate of water surface rise for blockage versus nonblockage.

Amplification of downstream flood stage due to damming of fine-grained rivers.

River dams provide many benefits, including flood control. However, due to constantly evolving channel morphology, downstream conveyance of floodwaters following dam closure is difficult to predict. Here, we test the hypothesis that the incised, enlarged channel downstream of dams provides enhanced water conveyance, using a case study from the lower Yellow River, China. We find that, although flood stage is lowered for small floods, counterintuitively, flood stage downstream of a dam can be amplified for moderate and large floods. This arises because bed incision is accompanied by sediment coarsening, which facilitates development of large dunes that increase flow resistance and reduce velocity relative to pre-dam conditions. Our findings indicate the underlying mechanism for such flood amplification may occur in >80% of fine-grained rivers, and suggest the need to reconsider flood control strategies in such rivers worldwide.

Global Surgery and Mercy Ships.

Two-thirds of the world population do not have access to safe, affordable and timely surgery. This global surgical crisis largely affects low and middle-income countries, and it will surpass the challenges created by communicable diseases. The barriers of access to surgery range from cost of surgery and patient transportation to availability and quality of surgical infrastructure and providers. Mercy Ships is a Non-Governmental Organisation (NGO) providing free world-class life-saving and life-transforming surgery to the poorest of the poor in West Africa. In order to address barriers to access surgical assessment and care, Mercy Ships switched from centralised patient selection mainly in port cities or capitals to decentralised selection strategy staffed by experienced nursing teams travelling to remote locations nearer to patients' homes. In this way, the under-served rural population is given equal opportunity to access Mercy Ships' free specialised surgical services. In each country served by the Mercy Ships, a 5 year country engagement program is created to focus on improving the quality of life for people living with disease, disfigurement and disability through free direct medical service to reduce the burden of unmet surgical needs. Moreover, our Medical Capacity Building teams concentrate in improving infrastructure and quality control, equipment donation and maintenance. Lastly, Mercy Ships partner with government and policy makers to improve and strengthen their local surgical care delivery system as an indispensable part of the healthcare system. In this vast sea of global surgical crisis, the vision of the Mercy Ships is to eradicate the 'disease of poverty' and effectively do itself out of a job. Mercy Ships' new and the world's largest (37,000 ton) purpose-built hospital ship, the Global Mercy, is joining our current ship, the Africa Mercy (16,500 ton) to save lives and to strengthen local surgical care service. This will more than double our capacity and impact in sub-Saharan Africa following COVID-19 pandemic. Moreover our state-of-art on-board simulation laboratories and traditional practical training of local healthcare providers will further enhance and build their medical capacity. The Global Mercy will become the largest floating and training platform to train next generation African medical and health care professionals so that they can save countless lives by training others in the future. We therefore invite you to partner with us in bringing hope and healing to the forgotten poor in West Africa.

The role of lateral erosion in the evolution of nondendritic drainage networks to dendricity and the persistence of dynamic networks.

Dendritic, i.e., tree-like, river networks are ubiquitous features on Earth's landscapes; however, how and why river networks organize themselves into this form are incompletely understood. A branching pattern has been argued to be an optimal state. Therefore, we should expect models of river evolution to drastically reorganize (suboptimal) purely nondendritic networks into (more optimal) dendritic networks. To date, current physically based models of river basin evolution are incapable of achieving this result without substantial allogenic forcing. Here, we present a model that does indeed accomplish massive drainage reorganization. The key feature in our model is basin-wide lateral incision of bedrock channels. The addition of this submodel allows for channels to laterally migrate, which generates river capture events and drainage migration. An important factor in the model that dictates the rate and frequency of drainage network reorganization is the ratio of two parameters, the lateral and vertical rock erodibility constants. In addition, our model is unique from others because its simulations approach a dynamic steady state. At a dynamic steady state, drainage networks persistently reorganize instead of approaching a stable configuration. Our model results suggest that lateral bedrock incision processes can drive major drainage reorganization and explain apparent long-lived transience in landscapes on Earth.

Development and implementation of guidelines for the management of depression: a systematic review.

OBJECTIVE: To evaluate the development and implementation of clinical practice guidelines for the management of depression globally. METHODS: We conducted a systematic review of existing guidelines for the management of depression in adults with major depressive or bipolar disorder. For each identified guideline, we assessed compliance with measures of guideline development quality (such as transparency in guideline development processes and funding, multidisciplinary author group composition, systematic review of comparative efficacy research) and implementation (such as quality indicators). We compared guidelines from low- and middle-income countries with those from high-income countries. FINDINGS: We identified 82 national and 13 international clinical practice guidelines from 83 countries in 27 languages. Guideline development processes and funding sources were explicitly specified in a smaller proportion of guidelines from low- and middle-income countries (8/29; 28%) relative to high-income countries (35/58; 60%). Fewer guidelines (2/29; 7%) from low- and middle-income countries, relative to high-income countries (22/58; 38%), were authored by a multidisciplinary development group. A systematic review of comparative effectiveness was conducted in 31% (9/29) of low- and middle-income country guidelines versus 71% (41/58) of high-income country guidelines. Only 10% (3/29) of low- and middle-income country and 19% (11/58) of high-income country guidelines described plans to assess quality indicators or recommendation adherence. CONCLUSION: Globally, guideline implementation is inadequately planned, reported and measured. Narrowing disparities in the development and implementation of guidelines in low- and middle-income countries is a priority. Future guidelines should present strategies to implement recommendations and measure feasibility, cost-effectiveness and impact on health outcomes.

How canyons evolve by incision into bedrock: Rainbow Canyon, Death Valley National Park, United States.

Incising rivers may be confined by low-slope, erodible hillslopes or steep, resistant sidewalls. In the latter case, the system forms a canyon. We present a morphodynamic model that includes the essential elements of a canyon incising into a plateau, including 1) abrasion-driven channel incision, 2) migration of a canyon-head knickpoint, 3) sediment feed from an alluvial channel upstream of the knickpoint, and 4) production of sediment by sidewall collapse. We calculate incision in terms of collision of clasts with the bed. We calculate knickpoint migration using a moving-boundary formulation that allows a slope discontinuity where the channel head meets an alluvial plateau feeder channel. Rather than modeling sidewall collapse events, we model long-term behavior using a constant sidewall slope as the channel incises. Our morphodynamic model specifically applies to canyon, rather than river-hillslope evolution. We implement it for Rainbow Canyon, CA. Salient results are as follows: 1) Sediment supply from collapsing canyon sidewalls can be substantially larger than that supplied from the feeder channel on the plateau. 2) For any given quasi-equilibrium canyon bedrock slope, two conjugate slopes are possible for the alluvial channel upstream, with the lower of the two corresponding to a substantially lower knickpoint migration rate and higher preservation potential. 3) Knickpoint migration occurs at a substantially faster time scale than regrading of the bedrock channel itself, underlying the significance of disequilibrium processes. Although implemented for constant climactic conditions, the model warrants extension to long-term climate variation.

The role of saltwater and waves in continental shelf formation with seaward migrating clinoform.

Continental shelves have generally been interpreted as drowned coastal plains associated with the allogenic effect of sea-level variation. Here, without disputing this mechanism we describe an alternative autogenic mechanism for subaqueous shelf formation, driven by the presence of dissolved salt in seawater and surface waves. We use a numerical model describing flow hydrodynamics, sediment transport, and morphodynamics in order to do this. More specifically, we focus on two major aspects: 1) the role of saltwater in the subaqueous construction of continental shelves and 2) the transformation of these shelves into seaward-migrating clinoforms under the condition of repeated pulses of water and sediment input and steady wave effects, but no allogenic forcing such as sea-level change. In the case for which the receiving basin contains fresh water of the same density as the sediment-laden river water, the hyperpycnal river water plunges to form a turbidity current that can run out to deep water. In the case for which the receiving basin contains sea water but the river contains sediment-laden fresh water, the hypopycnal river water forms a surface plume that deposits sediment proximally. This proximate proto-shelf can then grow to wave base, after which wave-supported turbidity currents can extend it seaward. The feature we refer to is synonymous with near-shore mud belts.

Universal relation with regime transition for sediment transport in fine-grained rivers.

Fine-grained sediment (grain size under 2,000 µm) builds floodplains and deltas, and shapes the coastlines where much of humanity lives. However, a universal, physically based predictor of sediment flux for fine-grained rivers remains to be developed. Herein, a comprehensive sediment load database for fine-grained channels, ranging from small experimental flumes to megarivers, is used to find a predictive algorithm. Two distinct transport regimes emerge, separated by a discontinuous transition for median bed grain size within the very fine sand range (81 to 154 µm), whereby sediment flux decreases by up to 100-fold for coarser sand-bedded rivers compared to river with silt and very fine sand beds. Evidence suggests that the discontinuous change in sediment load originates from a transition of transport mode between mixed suspended bed load transport and suspension-dominated transport. Events that alter bed sediment size near the transition may significantly affect fluviocoastal morphology by drastically changing sediment flux, as shown by data from the Yellow River, China, which, over time, transitioned back and forth 3 times between states of high and low transport efficiency in response to anthropic activities.

Flow directionality of pristine meandering rivers is embedded in the skewing of high-amplitude bends and neck cutoffs.

Information concerning the dynamics of river meandering is embedded in their planforms. Here, we focus on how bend skewing varies with increasing sinuosity, and how flow direction is embedded in bend skewing. It has often been thought that upstream-skewed bends are dominant within a sufficiently long reach. These bends may allow a reasonable inference as to the direction of flow. Here we consider this issue using 20 reaches of freely meandering alluvial rivers that are in remote locations, generally far from human influence. We find that low-amplitude bends tend to be downstream-, rather than upstream-skewed. Bends with sinuosity greater than 2.6, however, are predominantly upstream-skewed. Of particular interest are the neck cutoffs, all chosen to be relatively recent according to their position related to the main channel: 84% of these are upstream-skewed. Neck cutoffs, which have likely evolved directly from bends of the highest sinuosity, represent the planform feature most likely to have flow direction embedded in them. The field data suggest that meander bends without external forcing such as engineering works tend to evolve from downstream-skewed low-sinuosity bends to upstream-skewed high-sinuosity bends before cutoff. This process can be reproduced, to some extent, using models coupling sedimentary dynamics with flow dynamics.

Process evaluation in the field: global learnings from seven implementation research hypertension projects in low-and middle-income countries.

BACKGROUND: Process evaluation is increasingly recognized as an important component of effective implementation research and yet, there has been surprisingly little work to understand what constitutes best practice. Researchers use different methodologies describing causal pathways and understanding barriers and facilitators to implementation of interventions in diverse contexts and settings. We report on challenges and lessons learned from undertaking process evaluation of seven hypertension intervention trials funded through the Global Alliance of Chronic Diseases (GACD). METHODS: Preliminary data collected from the GACD hypertension teams in 2015 were used to inform a template for data collection. Case study themes included: (1) description of the intervention, (2) objectives of the process evaluation, (3) methods including theoretical basis, (4) main findings of the study and the process evaluation, (5) implications for the project, policy and research practice and (6) lessons for future process evaluations. The information was summarized and reported descriptively and narratively and key lessons were identified. RESULTS: The case studies were from low- and middle-income countries and Indigenous communities in Canada. They were implementation research projects with intervention arm. Six theoretical approaches were used but most comprised of mixed-methods approaches. Each of the process evaluations generated findings on whether interventions were implemented with fidelity, the extent of capacity building, contextual factors and the extent to which relationships between researchers and community impacted on intervention implementation. The most important learning was that although process evaluation is time consuming, it enhances understanding of factors affecting implementation of complex interventions. The research highlighted the need to initiate process evaluations early on in the project, to help guide design of the intervention; and the importance of effective communication between researchers responsible for trial implementation, process evaluation and outcome evaluation. CONCLUSION: This research demonstrates the important role of process evaluation in understanding implementation process of complex interventions. This can help to highlight a broad range of system requirements such as new policies and capacity building to support implementation. Process evaluation is crucial in understanding contextual factors that may impact intervention implementation which is important in considering whether or not the intervention can be translated to other contexts.

The role of context in implementation research for non-communicable diseases: Answering the 'how-to' dilemma.

INTRODUCTION: Understanding context and how this can be systematically assessed and incorporated is crucial to successful implementation. We describe how context has been assessed (including exploration or evaluation) in Global Alliance for Chronic Diseases (GACD) implementation research projects focused on improving health in people with or at risk of chronic disease and how contextual lessons were incorporated into the intervention or the implementation process. METHODS: Using a web-based semi-structured questionnaire, we conducted a cross-sectional survey to collect quantitative and qualitative data across GACD projects (n = 20) focusing on hypertension, diabetes and lung diseases. The use of context-specific data from project planning to evaluation was analyzed using mixed methods and a multi-layered context framework across five levels; 1) individual and family, 2) community, 3) healthcare setting, 4) local or district level, and 5) state or national level. RESULTS: Project teams used both qualitative and mixed methods to assess multiple levels of context (avg. = 4). Methodological approaches to assess context were identified as formal and informal assessments, engagement of stakeholders, use of locally adapted resources and materials, and use of diverse data sources. Contextual lessons were incorporated directly into the intervention by informing or adapting the intervention, improving intervention participation or improving communication with participants/stakeholders. Provision of services, equipment or information, continuous engagement with stakeholders, feedback for personnel to address gaps, and promoting institutionalization were themes identified to describe how contextual lessons are incorporated into the implementation process. CONCLUSIONS: Context is regarded as critical and influenced the design and implementation of the GACD funded chronic disease interventions. There are different approaches to assess and incorporate context as demonstrated by this study and further research is required to systematically evaluate contextual approaches in terms of how they contribute to effectiveness or implementation outcomes.

Bedrock-alluvial streams with knickpoint and plunge pool that migrate upstream with permanent form.

Purely alluvial rivers cannot sustain knickpoints along their long profiles, as they would be obliterated by diffusional morphodynamics. Bedrock streams with a partial alluvial cover, however, form and sustain slope breaks over long periods of time. Here we consider the case of an initial profile of a bedrock-alluvial stream with a sharp slope break, or knickpoint, from high to low midway. We show that if the initial flow is sufficiently Froude-supercritical in the upstream reach and Froude-subcritical in the downstream reach, a three-tiered structure can evolve at the slope break: a hydraulic jump at the water surface; a scour hole in the alluvium above the bedrock, and a plunge pool carved into bedrock. Once the profile adjusts to balance uplift, it can migrate upstream without changing form.

Task-shifting for cardiovascular risk factor management: lessons from the Global Alliance for Chronic Diseases.

Task-shifting to non-physician health workers (NPHWs) has been an effective model for managing infectious diseases and improving maternal and child health. There is inadequate evidence to show the effectiveness of NPHWs to manage cardiovascular diseases (CVDs). In 2012, the Global Alliance for Chronic Diseases funded eight studies which focused on task-shifting to NPHWs for the management of hypertension. We report the lessons learnt from the field. From each of the studies, we obtained information on the types of tasks shifted, the professional level from which the task was shifted, the training provided and the challenges faced. Additionally, we collected more granular data on 'lessons learnt ' throughout the implementation process and 'design to implementation' changes that emerged in each project. The tasks shifted to NPHWs included screening of individuals, referral to physicians for diagnosis and management, patient education for lifestyle improvement, follow-up and reminders for medication adherence and appointments. In four studies, tasks were shifted from physicians to NPHWs and in four studies tasks were shared between two different levels of NPHWs. Training programmes ranged between 3 and 7 days with regular refresher training. Two studies used clinical decision support tools and mobile health components. Challenges faced included system level barriers such as inability to prescribe medicines, varying skill sets of NPHWs, high workload and staff turnover. With the acute shortage of the health workforce in low-income and middle-income countries (LMICs), achieving better health outcomes for the prevention and control of CVD is a major challenge. Task-shifting or sharing provides a practical model for the management of CVD in LMICs.