Malaria-eliminating countries achieved remarkable success in reducing their malaria burdens between 2000 and 2010. As a result, the epidemiology of malaria in these settings has become more complex. ...Malaria is increasingly imported, caused by Plasmodium vivax in settings outside sub-Saharan Africa, and clustered in small geographical areas or clustered demographically into subpopulations, which are often predominantly adult men, with shared social, behavioural, and geographical risk characteristics. The shift in the populations most at risk of malaria raises important questions for malaria-eliminating countries, since traditional control interventions are likely to be less effective. Approaches to elimination need to be aligned with these changes through the development and adoption of novel strategies and methods. Knowledge of the changing epidemiological trends of malaria in the eliminating countries will ensure improved targeting of interventions to continue to shrink the malaria map.
The retention of episodic-like memory is enhanced, in humans and animals, when something novel happens shortly before or after encoding. Using an everyday memory task in mice, we sought the neurons ...mediating this dopamine-dependent novelty effect, previously thought to originate exclusively from the tyrosine-hydroxylase-expressing (TH
) neurons in the ventral tegmental area. Here we report that neuronal firing in the locus coeruleus is especially sensitive to environmental novelty, locus coeruleus TH
neurons project more profusely than ventral tegmental area TH
neurons to the hippocampus, optogenetic activation of locus coeruleus TH
neurons mimics the novelty effect, and this novelty-associated memory enhancement is unaffected by ventral tegmental area inactivation. Surprisingly, two effects of locus coeruleus TH
photoactivation are sensitive to hippocampal D
/D
receptor blockade and resistant to adrenoceptor blockade: memory enhancement and long-lasting potentiation of synaptic transmission in CA1 ex vivo. Thus, locus coeruleus TH
neurons can mediate post-encoding memory enhancement in a manner consistent with possible co-release of dopamine in the hippocampus.
Transplantation of human embryonic stem cell (hESC)-derived retinal pigment epithelial (RPE) cells offers the potential for benefit in macular degeneration. Previous trials have reported improved ...visual acuity (VA), but lacked detailed analysis of retinal structure and function in the treated area.
Phase 1/2 open-label dose-escalation trial to evaluate safety and potential efficacy (clinicaltrials.gov identifier, NCT01469832).
Twelve participants with advanced Stargardt disease (STGD1), the most common cause of macular degeneration in children and young adults.
Subretinal transplantation of up to 200 000 hESC-derived RPE cells with systemic immunosuppressive therapy for 13 weeks.
The primary end points were the safety and tolerability of hESC-derived RPE cell administration. We also investigated evidence of the survival of transplanted cells and measured retinal structure and function using microperimetry and spectral-domain OCT.
Focal areas of subretinal hyperpigmentation developed in all participants in a dose-dependent manner in the recipient retina and persisted after withdrawal of systemic immunosuppression. We found no evidence of uncontrolled proliferation or inflammatory responses. Borderline improvements in best-corrected VA in 4 participants either were unsustained or were matched by a similar improvement in the untreated contralateral eye. Microperimetry demonstrated no evidence of benefit at 12 months in the 12 participants. In one instance at the highest dose, localized retinal thinning and reduced sensitivity in the area of hyperpigmentation suggested the potential for harm. Participant-reported quality of life using the 25-item National Eye Institute Visual Function Questionnaire indicated no significant change.
Subretinal hyperpigmentation is consistent with the survival of viable transplanted hESC-derived RPE cells, but may reflect released pigment in their absence. The findings demonstrate the value of detailed analysis of spatial correlation of retinal structure and function in determining with appropriate sensitivity the impact of cell transplantation and suggest that intervention in early stage of disease should be approached with caution. Given the slow rate of progressive degeneration at this advanced stage of disease, any protection against further deterioration may be evident only after a more extended period of observation.
Yield stability is fundamental to global food security in the face of climate change, and better strategies are needed for buffering crop yields against increased weather variability. Regional- scale ...analyses of yield stability can support robust inferences about buffering strategies for widely-grown staple crops, but have not been accomplished. We present a novel analytical approach, synthesizing 2000-2014 data on weather and soil factors to quantify their impact on county-level maize yield stability in four US states that vary widely in these factors (Illinois, Michigan, Minnesota and Pennsylvania). Yield stability is quantified as both 'downside risk' (minimum yield potential, MYP) and 'volatility' (temporal yield variability). We show that excessive heat and drought decreased mean yields and yield stability, while higher precipitation increased stability. Soil water holding capacity strongly affected yield volatility in all four states, either directly (Minnesota and Pennsylvania) or indirectly, via its effects on MYP (Illinois and Michigan). We infer that factors contributing to soil water holding capacity can help buffer maize yields against variable weather. Given that soil water holding capacity responds (within limits) to agronomic management, our analysis highlights broadly relevant management strategies for buffering crop yields against climate variability, and informs region-specific strategies.
•FAO56 advances in ET computation are retrospectively reviewed and analyzed.•Definition, procedures and advances in computing reference ET are reviewed.•Estimation, use and transferability of Kc's ...and their adjustment to local conditions are discussed.•The estimation of evaporation and transpiration with the dual Kc is analyzed.•ET estimation under non-standard conditions and with remote sensing are reviewed.
The FAO Irrigation and Drainage Paper No 56 on Crop Evapotranspiration has been in publication for more than 15 years. The paper advanced the accuracy and consistency of operational computation of evapotranspiration (ET) for agricultural and other land use types. The paper included updated definition and procedures for computing reference ET, an update on estimating crop coefficients (Kc), the adoption of the dual Kc for separate estimation of crop transpiration and soil evaporation, and an upgraded estimation of crop ET under water and salt stress and other non-standard conditions. These advances are retrospectively reviewed in this paper. The advances in computing reference ET were primarily through the adoption of specific and consistent characteristics for the grass reference crop using the Penman–Monteith equation parameterized to represent a living reference surface. That standardization made the Kc more visual and understandable as a factor that relates the ET characteristics of a specific crop to the defined reference crop. Methodologies were introduced to estimate reference ET under conditions of limited weather data while retaining the use of the PM equation. Advances in adopted Kc research included techniques to estimate Kc based on the architecture of crops, notably height and fraction of ground cover. Other advances included consistent and straight-forward techniques for applying the dual Kc method via soil and evaporation process modeling on a daily timestep. New techniques were introduced for using yield response and salinity threshold values to estimate reductions in ET caused by elevated soil salinity. In addition, recommendations were given for adjusting ET for impacts of surface mulching, intercropping, and sparse vegetation. The successful adoption of the FAO–PM reference ET and Kc approaches owes primarily to the simplicity, yet relatively high level of robustness of the procedures, and to transferability and repeatability of the Kc method. Future development needs are discussed.
Minerals in the rhizosphere Jilling, Andrea; Keiluweit, Marco; Contosta, Alexandra R. ...
Biogeochemistry,
07/2018, Volume:
139, Issue:
2
Journal Article
Peer reviewed
Open access
Despite decades of research progress, ecologists are still debating which pools and fluxes provide nitrogen (N) to plants and soil microbes across different ecosystems. Depolymerization of soil ...organic N is recognized as the rate-limiting step in the production of bioavailable N, and it is generally assumed that detrital N is the main source. However, in many mineral soils, detrital polymers constitute a minor fraction of total soil organic N. The majority of organic N is associated with clay-sized particles where physicochemical interactions may limit the accessibility of N-containing compounds. Although mineral-associated organic matter (MAOM) has historically been considered a critical, but relatively passive, reservoir of soil N, a growing body of research now points to the dynamic nature of mineral-organic associations and their potential for destabilization. Here we synthesize evidence from biogeoscience and soil ecology to demonstrate how MAOM is an important, yet overlooked, mediator of bioavailable N, especially in the rhizosphere. We highlight several biochemical strategies that enable plants and microbes to disrupt mineral-organic interactions and access MAOM. In particular, root-deposited low-molecular-weight exudates may enhance the mobilization and solubilization of MAOM, increasing its bioavailability. However, the competitive balance between the possible fates of N monomers—bound to mineral surfaces versus dissolved and available for assimilation—will depend on the specific interaction between mineral properties, soil solution, mineral-bound organic matter, and microbes. Building off our emerging understanding of MAOM as a source of bioavailable N, we propose a revision of the Schimel and Bennett (Ecology 85:591–602, 2004) model (which emphasizes N depolymerization), by incorporating MAOM as a potential proximal mediator of bioavailable N.
Background Pulmonary embolism (PE) remains a significant cause of hospital admission and health-care costs. Estimates of PE incidence came from the 1990s, and data are limited to describe trends in ...hospital admissions for PE over the past decade. Methods We analyzed Nationwide Inpatient Sample data from 1993 to 2012 to identify patients admitted with PE. We included admissions with International Classification of Diseases, 9th revision, codes listing PE as the principal diagnosis as well as admissions with PE listed secondary to principal diagnoses of respiratory failure or DVT. Massive PE was defined by mechanical ventilation, vasopressors, or nonseptic shock. Outcomes included hospital lengths of stay, adjusted charges, and all-cause hospital mortality. Linear regression was used to analyze changes over time. Results Admissions for PE increased from 23 per 100,000 in 1993 to 65 per 100,000 in 2012 ( P < .001). The percent of admissions meeting criteria for massive PE decreased (5.3% to 4.4%, P = .002), but the absolute number of admissions for massive PE increased (from 1.5 to 2.8 per 100,000, P < .001). Median length of stay decreased from 8 (interquartile range IQR, 6-11) to 4 (IQR, 3-6) days ( P < .001). Adjusted hospital charges increased from $16,475 (IQR, $10,748-$26,211) in 1993 to $25,728 (IQR, $15,505-$44,493) in 2012 ( P < .001). All-cause hospital mortality decreased from 7.1% to 3.2% ( P < .001), but population-adjusted deaths during admission for PE increased from 1.6 to 2.1 per 100,000 ( P < .001). Conclusions Total admissions and hospital charges for PE have increased over the past two decades. However, the population-adjusted admission rate has increased disproportionately to the incidence of patients with severe PE. We hypothesize that these findings reflect a concerning national movement toward more admissions of less severe PE.
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