Drivers of seedling establishment success in dryland restoration efforts.

Restoration of degraded drylands is urgently needed to mitigate climate change, reverse desertification and secure livelihoods for the two billion people who live in these areas. Bold global targets have been set for dryland restoration to restore millions of hectares of degraded land. These targets have been questioned as overly ambitious, but without a global evaluation of successes and failures it is impossible to gauge feasibility. Here we examine restoration seeding outcomes across 174 sites on six continents, encompassing 594,065 observations of 671 plant species. Our findings suggest reasons for optimism. Seeding had a positive impact on species presence: in almost a third of all treatments, 100% of species seeded were growing at first monitoring. However, dryland restoration is risky: 17% of projects failed, with no establishment of any seeded species, and consistent declines were found in seeded species as projects matured. Across projects, higher seeding rates and larger seed sizes resulted in a greater probability of recruitment, with further influences on species success including site aridity, taxonomic identity and species life form. Our findings suggest that investigations examining these predictive factors will yield more effective and informed restoration decision-making.

Evaluation of environmental and anthropogenic influences on ambient background metal and metalloid concentrations in soil.

There has been a global shift in environmental risk assessment towards quantifying ambient background concentrations of metals/metalloids in soil. Whilst bedrock has been shown to be a key driver of metal/metalloid variability in soil, few researchers have assessed controls of ambient background concentrations in soils of similar bedrock. A soil survey was undertaken ofGreater Melbourne, Greater Geelong, Ballarat and Mitchell in Victoria, Australia for elements of potential environmental concern: As, Cd, Cr, Cu, Ni, Hg, Pb and Zn. Samples (n=622) were collected from surface (0 to 0.1m) and sub-surface (0.3 to 0.6m) soils, overlying Tertiary-Quaternary basalt, Tertiary sediments and Silurian siltstone and sandstone. In addition, background soil data from open-source environmental assessment reports (n=5512) were collated to support the understanding of natural enrichment, particularly at depths >0.6m. Factor analysis, supported by correlation analysis and auxiliary geo-spatial data, provided an improved understanding of where and how background metal/metalloid enrichment occurs in the environment. Weathering during paleoclimates was the predominant influence of background metal/metalloid variability in soils overlying similar bedrock. Other key influences of metal/metalloid variability in soil included hydraulic leaching of alkali elements, biological cycling, topography and alluvial transfer of silt and sand from mineralised regions. In addition, urbanisation positively correlated with Pb and Zn concentrations in surface soils suggesting that anthropogenic activities may have resulted in diffuse Pb and Zn contamination of urban soil.

Spin transitions in bis(amidinato)-N-heterocyclic carbene iron(II) and iron(III) complexes.

In contrast to high spin pyridyl diimine iron(ii) dichloride complexes, analogous bis(amidinato)-N-heterocyclic carbene iron(ii) and iron(iii) complexes demonstrate complex magnetic behaviour. In the solid state, they are best described as intermediate spin complexes at low temperatures that demonstrate gradual spin transitions beginning near or below room temperature. Treating the bis(amidinato)-N-heterocyclic carbene iron(ii) complex with an aryl azide revealed enhanced reactivity compared to analogous complexes supported by pyridyl diimine ligands.

Esophageal rupture diagnosed with bedside ultrasound.

A 69-year-old man presented to the emergency department with hematemesis, hypotension, tachycardia, and hypothermia. The emergency physician performed a bedside ultrasound of the chest, heart, and abdomen. The heart was unable to be visualized in the parasternal, apical, or subxiphoid windows, and free fluid and particulate matter were visualized in the chest and abdomen. The inability to visualize the heart in the normal cardiac windows suggested a diagnosis of pneumopericardium. Based upon the patient's presenting symptoms and ultrasound findings, an esophageal perforation was suspected. Esophageal perforation is a medical emergency. Deterioration and death due to sepsis can occur within hours of presentation [6]. Although there is a great deal of literature discussing the diagnosis of esophageal perforation by chest radiograph, computed tomography (CT), and esophagography, there are no articles on the role of ultrasound. Esophageal perforation may result in the communication of air between the esophagus and pericardium and the leakage of gastric contents into the chest and peritoneal cavity. The presence of air in the pericardial sac results in nonvisualization of the heart on ultrasound. Fluid in the chest and abdomen may be visualized in the posterior upper abdominal windows. Although these ultrasound findings alone are not entirely specific for esophageal perforation, when coupled with a high index of suspicion due to the patient presentation, ultrasound can be one of the most portable, readily available, low-cost, and minimally invasive techniques to make the diagnosis of esophageal perforation.