Machine learning and global vegetation: random forests for downscaling and gap filling

Drought is a devastating natural disaster, during which water shortage often manifests itself in the health of vegetation. Unfortunately, it is difficult to obtain high-resolution vegetation drought impact information that is spatially and temporally consistent. While remotely sensed products can provide part of this information, they often suffer from data gaps and limitations with respect to their spatial or temporal resolution. A persistent feature among remote-sensing products is the trade-off between the spatial resolution and revisit time: high temporal resolution is met with coarse spatial resolution and vice versa. Machine learning methods have been successfully applied in a wide range of remote-sensing and hydrological studies. However, global applications to resolve drought impacts on vegetation dynamics still need to be made available, as there is significant potential for such a product to aid with improved drought impact monitoring. To this end, this study predicted global vegetation dynamics based on the enhanced vegetation index (evi) and the popular Random forest (RF) regressor algorithm at 0.1°. We assessed the applicability of RF as a gap-filling and downscaling tool to generate global evi estimates that are spatially and temporally consistent. To do this, we trained an RF regressor with 0.1° evi data, using a host of features indicative of the water and energy balances experienced by vegetation, and evaluated the performance of this new product. Next, to test whether the RF is robust in terms of spatial resolution, we downscale the global evi: the model trained on 0.1° data is used to predict evi at a 0.01° resolution. The results show that the RF can capture global evi dynamics at both a 0.1° resolution (RMSE: 0.02–0.4) and at a finer 0.01° resolution (RMSE: 0.04–0.6). Overall errors were higher in the downscaled 0.01° product compared with the 0.1° product. Nevertheless, relative increases remained small, demonstrating that RF can be used to create downscaled and temporally consistent evi products. Additional error analysis revealed that errors vary spatiotemporally, with underrepresented land cover types and periods of extreme vegetation conditions having the highest errors. Finally, this model is used to produce global, spatially continuous evi products at both a 0.1 and 0.01° spatial resolution for 2003–2013 at an 8 d frequency.</p

A comparative analysis of components incorporated in conservation priority assessments: a case study based on South African species of terrestrial mammals.

Assessing the risk of extinction to species forms an essential part of regional conservation initiatives that facilitate the allocation of limited resources for conservation. The present study conducted conservation priority assessments for 221 South African terrestrial mammal species using existing data sources. These data sources included regional IUCN Red List assessments, regional geographic distributions, relative endemism, taxonomic distinctiveness, relative body mass and human density. These components were in turn subjected to two quantitative conservation priority assessment techniques in an attempt to determine regional conservation priorities for South African terrestrial mammals. The top 22 mammal species (i.e. the top 10% of assessed species) identified by both regional conservation priority assessment techniques to be of conservation priority, consistently identified 13 South African terrestrial mammal species to be of high conservation priority. Seven of the 13 species were from the order Afrosoticida, two species from the order Eulipotyphla, with one species each from the orders Chiroptera, Lagomorpha, Pholidota, and Rodentia. More importantly, 12 of the 13 mammal species were also listed as threatened in the 2004 Red Data Book of South African Mammals. These results suggest that the two conservation priority assessment techniques used in the present study may represent a practical and quantitative method for determining regional conservation priorities, and include measures that represent vulnerability, conservation value, and threat.DST-NRF Centre of Excellence for Invasion Biolog

A comparative analysis of components incorporated in conservation priority assessments: a case study based on South African species of terrestrial mammals.

Assessing the risk of extinction to species forms an essential part of regional conservation initiatives that facilitate the allocation of limited resources for conservation. The present study conducted conservation priority assessments for 221 South African terrestrial mammal species using existing data sources. These data sources included regional IUCN Red List assessments, regional geographic distributions, relative endemism, taxonomic distinctiveness, relative body mass and human density. These components were in turn subjected to two quantitative conservation priority assessment techniques in an attempt to determine regional conservation priorities for South African terrestrial mammals. The top 22 mammal species (i.e. the top 10% of assessed species) identified by both regional conservation priority assessment techniques to be of conservation priority, consistently identified 13 South African terrestrial mammal species to be of high conservation priority. Seven of the 13 species were from the order Afrosoticida, two species from the order Eulipotyphla, with one species each from the orders Chiroptera, Lagomorpha, Pholidota, and Rodentia. More importantly, 12 of the 13 mammal species were also listed as threatened in the 2004 Red Data Book of South African Mammals. These results suggest that the two conservation priority assessment techniques used in the present study may represent a practical and quantitative method for determining regional conservation priorities, and include measures that represent vulnerability, conservation value, and threat.DST-NRF Centre of Excellence for Invasion Biolog

Early age properties of low-calcium fly ash geopolymer concrete suitable for ambient curing

Geopolymer is a promising alternative binder to Portland cement. It is produced mostly from by-product materials such as fly ash and blast furnace slag; hence recognised as a low-emission alternative binder for concrete. Recent studies have shown that the properties of geopolymers are similar or superior to those of the OPC binder that is traditionally used for concrete. Most of the previous studies employed heat curing for setting and hardening of fly ash geopolymer mixtures. Heat curing process requires special arrangements which is energy-consuming and may not be feasible to apply in cast-in-situ concreting. Therefore, development of geopolymer mixtures suitable for curing at normal temperature will widen its application. This paper presents a study on low calcium fly ash based geopolymer concrete cured in ambient temperature (23oC) without additional heat. Small amount of additives were added with fly ash to accelerate the early-age reaction. Setting times of geopolymer pastes, and workability and compressive strength of geopolymer mortar were studied. The effects of the additives and binder content in the mixtures were determined from experimental results. The results show that inclusion of additives with fly ash significantly enhanced the early age properties. Setting time reduced to reasonable values and compressive strength increased to enable early de-moulding of specimens. Compressive strength increased with the increase of binder content. However, workability results showed an optimum binder content for the fly ash geopolymer blended with the additives. The results suggest that suitable geopolymer mixtures can be designed for ambient curing with low calcium fly ash and the additives as partial replacement

What patients with pulmonary fibrosis and their partners think

Pulmonary fibrosis greatly impacts patients and their partners. Unmet needs of patients are increasingly acknowledged; the needs of partners often remain unnoticed. Little is known about the best way to educate patients and partners. We investigated pulmonary fibrosis patients’ and partners’ perspectives and preferences in care, and the differences in these between the Netherlands and Germany. Additionally, we evaluated whether interactive interviewing could be a novel education method in this population. Patients and partners were interviewed during pulmonary fibrosis patient information meetings. In the Netherlands, voting boxes were used and results were projected directly. In Germany, questionnaires were used. In the Netherlands, 278 patients and partners participated; in Germany, 51. Many participants experienced anxiety. Almost all experienced misunderstanding, because people do not know what pulmonary fibrosis is. All expressed a need for information, psychological support and care for partners. Use of the interactive voting system was found to be pleasant (70%) and informative (94%). This study improves the knowledge of care needs of patients with pulmonary fibrosis and their partners. There were no major differences between the Netherlands and Germany. Interactive interviewing could be an attractive method to acquire insights into the needs and preferences of patients and partners, while providing them with information at the same time

Renal artery stenosis-when to screen, what to stent?

Renal artery stensosis (RAS) continues to be a problem for clinicians, with no clear consensus on how to investigate and assess the clinical significance of stenotic lesions and manage the findings. RAS caused by fibromuscular dysplasia is probably commoner than previously appreciated, should be actively looked for in younger hypertensive patients and can be managed successfully with angioplasty. Atheromatous RAS is associated with increased incidence of cardiovascular events and increased cardiovascular mortality, and is likely to be seen with increasing frequency. Evidence from large clinical trials has led clinicians away from recommending interventional revascularisation towards aggressive medical management. There is now interest in looking more closely at patient selection for intervention, with focus on intervening only in patients with the highest-risk presentations such as flash pulmonary oedema, rapidly declining renal function and severe resistant hypertension. The potential benefits in terms of improving hard cardiovascular outcomes may outweigh the risks of intervention in this group, and further research is needed