Altered precipitation patterns resulting from climate change will have particularly significant consequences in water‐limited ecosystems, such as arid to semi‐arid ecosystems, where discontinuous ...inputs of water control biological processes. Given that these ecosystems cover more than a third of Earth's terrestrial surface, it is important to understand how they respond to such alterations. Altered water availability may impact both aboveground and belowground communities and the interactions between these, with potential impacts on ecosystem functioning; however, most studies to date have focused exclusively on vegetation responses to altered precipitation regimes. To synthesize our understanding of potential climate change impacts on dryland ecosystems, we present here a review of current literature that reports the effects of precipitation events and altered precipitation regimes on belowground biota and biogeochemical cycling. Increased precipitation generally increases microbial biomass and fungal:bacterial ratio. Few studies report responses to reduced precipitation but the effects likely counter those of increased precipitation. Altered precipitation regimes have also been found to alter microbial community composition but broader generalizations are difficult to make. Changes in event size and frequency influences invertebrate activity and density with cascading impacts on the soil food web, which will likely impact carbon and nutrient pools. The long‐term implications for biogeochemical cycling are inconclusive but several studies suggest that increased aridity may cause decoupling of carbon and nutrient cycling. We propose a new conceptual framework that incorporates hierarchical biotic responses to individual precipitation events more explicitly, including moderation of microbial activity and biomass by invertebrate grazing, and use this framework to make some predictions on impacts of altered precipitation regimes in terms of event size and frequency as well as mean annual precipitation. While our understanding of dryland ecosystems is improving, there is still a great need for longer term in situ manipulations of precipitation regime to test our model.
Oxidative stress is an important component of the cytopathology of equine spermatozoa undergoing storage as liquid or frozen semen. Damage to chromatin, membranes and proteins of sperm are important ...components of oxidative damage to sperm. Similarly, sperm are exposed to a variety of osmotic stresses during storage that result from exposure to hypertonic media or result as a consequence of osmotic changes induced during freezing. A number of changes induced during processing and storage of equine sperm also appear to induce apoptotic-like changes which may adversely affect sperm survival and function. These processes appear in many cases to be interrelated, and this review will examine current understanding of these processes on the equine sperm function.
Congenital heart defects constitute the most common human birth defect, however understanding of how these disorders originate is limited by our ability to model the human heart accurately in vitro. ...Here we report a method to generate developmentally relevant human heart organoids by self-assembly using human pluripotent stem cells. Our procedure is fully defined, efficient, reproducible, and compatible with high-content approaches. Organoids are generated through a three-step Wnt signaling modulation strategy using chemical inhibitors and growth factors. Heart organoids are comparable to age-matched human fetal cardiac tissues at the transcriptomic, structural, and cellular level. They develop sophisticated internal chambers with well-organized multi-lineage cardiac cell types, recapitulate heart field formation and atrioventricular specification, develop a complex vasculature, and exhibit robust functional activity. We also show that our organoid platform can recreate complex metabolic disorders associated with congenital heart defects, as demonstrated by an in vitro model of pregestational diabetes-induced congenital heart defects.
Biodiesel is one of the alternative fuels which is renewable and environmentally friendly and can be used in diesel engines with little or no modifications. In the present study, experimental ...investigations were carried out on the effects of biodiesel types, biodiesel fraction and physical properties on the combustion and performance characteristics of a (compression ignition) CI engine. The experimental work was conducted on a four-cylinder, four-stroke, (direct injection) DI and turbo-charged diesel engine by using biodiesel of waste oil, rapeseed oil and corn oil and normal diesel. Based on the measured parameters, detailed analyses were carried out on cylinder pressure, heat release rate and (brake specific fuel consumption) BSFC. It has been seen that the biodiesel types do not result in any significant differences in peak cylinder pressure and BSFC. The results also clearly indicate that the engine running with biodiesel have slightly higher in-cylinder pressure and heat release rate than the engine running with normal diesel. The BSFC for the engine running with neat biodiesel was higher than the engine running with normal diesel by up to 15%. It is also noticed that the physical properties of the biodiesel affect significantly the performance of the engine.
► Combustion and performance of CI (compression ignition) engine running with biodiesel were reviewed. ► The effects of feedstock source on in-cylinder pressure and BSFC (brake specific fuel consumption) have been investigated experimentally. ► The combustion characteristics of CI engine running with biodiesel blend have been reported. ► The effects of density, viscosity and lower heating value on the BSFC have been reported.
Biodiesel is one of the most promising renewable, alternative and environmentally friendly biofuels that can be used in diesel engine without any need for any modification in the engine. However, ...researchers have reported that the engines running with biodiesel emit NO
x
in higher concentrations. To address this problem, in the present study an experimental investigation has been carried out on the combustion, performance and emission characteristics of a compression ignition (CI) engine running with biodiesel under steady state conditions with a novel NO
x
reducing mechanism involving a water injections system. The experimental work has been conducted on a four-cylinder, four-stroke, direct injection (DI) as well as turbocharged diesel engine. In this investigation, biodiesel (produced from the rapeseed oil by transesterification process) has been used. During the experiments the in-cylinder pressure, specific fuel consumption, water injection flow rate, fuel flow rate and exhaust emission (NO
x
, CO, CO
2 and THC) were measured. The experimental results clearly indicate that water injection at a rate of 3 kg/h results in the reduction of NO
x
emission by about 50% without causing any significant change in the specific fuel consumption. Furthermore, the water injection in the intake manifold has little effect on the in-cylinder pressure and heat release rate of the CI engine under different operating conditions.
► Water has been injected at intake manifold in CI engine running with biodiesel. ► The peak cylinder pressure and heat release rate of CI engine are not affected. ► Brake specific fuel consumption and thermal efficiency do not change significantly. ► Intake manifold water injection reduces NO
x emission by up to 50%.
Marijuana is becoming legal in an increasing number of states for both medical and recreational use. Considerable controversy exists regarding the public health impact of these changes. The evidence ...for the legitimate medical use of marijuana or cannabinoids is limited to a few indications, notably HIV AIDS cachexia, nausea vomiting related to chemotherapy, neuropathic pain, and spasticity in multiple sclerosis. Although cannabinoids show therapeutic promise in other areas, robust clinical evidence is still lacking. The relationship between legalization and prevalence is still unknown. Although states where marijuana use is legal have higher rates of use than nonlegal states, these higher rates were generally found even prior to legalization. As states continue to proceed with legalization for both medical and recreational use, certain public health issues have become increasingly relevant, including the effects of acute marijuana intoxication on driving abilities, unintentional ingestion of marijuana products by children, the relationship between marijuana and opioid use, and whether there will be an increase in health problems related to marijuana use, such as dependence addiction, psychosis, and pulmonary disorders. In light of this rapidly shifting legal landscape, more research is urgently needed to better understand the impact of legalization on public health.
Automatic Modulation Classification (AMC) is a rapidly evolving technology, which can be employed in software defined radio structures, especially in 5G and 6G technology. Machine Learning (ML) can ...provide novel and efficient technology for modulation classification, especially for systems working in low signal to noise ratio (SNR). In this article, two dynamic systems not reliant on received signal phase lock and frequency lock are presented, with both employing ML to classify the modulation types for different received SNR. The first model is developed from the previous existing literatures, which utilises constellation images (CI) and image classification technology. Here, modulation types can be detected in a dynamic way without phase lock and frequency lock. In the second model, a new method named Graphic Representation of Features (GRF) is proposed, which represents the statistical features as a spider graph for ML. The concepts are tested and verified using simulations and RF data using a lab software defined radio (SDR). The results from the two models are compared. With the GRF techniques an overall classification accuracy of 59% is observed for 0 dB SNR and 86% at 10 dB SNR, compared to a random guess accuracy of 25%.
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