Fertilizer concentration and fertigation frequency: effects on electric conductivity and ions concentration in the soil solution

Fertirrigation allows total control of the amount of applied fertilizers to the soil as a function of crop demand. Fertigation relies on monitoring of soil ions to obtain the sustainability of soil chemical conditions. The continuous evaluation of ions in the soil solution also contributes to the estimation of the cycling rate of chemical elements and nutrient leaching in the field. The objective of this work was (i) to evaluate nitrate, potassium, sodium and electrical conductivity in the soil solution submitted to different concentrations of injection solution and fertigation frequency during one cycle of the "Grande Naine" banana in a non-cohesive Yellow Latosol and (ii) to evaluate the effects of concentration and fertigation frequency on yields of banana crop. The experiment was carried out according to a randomized block design with six treatments and four replications in a 3 x 2 factorial scheme with three concentrations of the injection solution (3, 10 and 15 g L-1) x two fertigation frequencies (3 and 7 days). The treatments influenced the values of the ion concentration in the soil solution in the soil profile corresponding to the depths of 0-0.30 e 0.30-0.60 m. The concentration of the injection solution and the interaction frequency x concentration influenced the electrical conductivity and nitrate concentration of the soil solution. There was no significant effect of the injection solution and fertigation frequency on production variables

No. 02: The State of Urban Food Insecurity in Southern Africa

The number of people living in urban areas is rising rapidly in Southern Africa. By mid-century, the region is expected to be 60% urban. Rapid urbanization is leading to growing food insecurity in the region’s towns and cities. This paper presents the results of the first ever regional study of the prevalence of food insecurity in Southern Africa. The AFSUN food security household survey was conducted simultaneously in 2008-9 in 11 cities in 8 SADC countries. The results confirm high levels of food insecurity amongst the urban poor in terms of food availability, accessibility, reliability and dietary diversity. The survey provides important insights into the causes of food insecurity and the kinds of households that are most vulnerable to food insecurity. It also shows the heavy reliance of the urban poor on informal food sources and the growing importance of supermarket chains

Analysis of shared heritability in common disorders of the brain

ience, this issue p. eaap8757 Structured Abstract INTRODUCTION Brain disorders may exhibit shared symptoms and substantial epidemiological comorbidity, inciting debate about their etiologic overlap. However, detailed study of phenotypes with different ages of onset, severity, and presentation poses a considerable challenge. Recently developed heritability methods allow us to accurately measure correlation of genome-wide common variant risk between two phenotypes from pools of different individuals and assess how connected they, or at least their genetic risks, are on the genomic level. We used genome-wide association data for 265,218 patients and 784,643 control participants, as well as 17 phenotypes from a total of 1,191,588 individuals, to quantify the degree of overlap for genetic risk factors of 25 common brain disorders. RATIONALE Over the past century, the classification of brain disorders has evolved to reflect the medical and scientific communities' assessments of the presumed root causes of clinical phenomena such as behavioral change, loss of motor function, or alterations of consciousness. Directly observable phenomena (such as the presence of emboli, protein tangles, or unusual electrical activity patterns) generally define and separate neurological disorders from psychiatric disorders. Understanding the genetic underpinnings and categorical distinctions for brain disorders and related phenotypes may inform the search for their biological mechanisms. RESULTS Common variant risk for psychiatric disorders was shown to correlate significantly, especially among attention deficit hyperactivity disorder (ADHD), bipolar disorder, major depressive disorder (MDD), and schizophrenia. By contrast, neurological disorders appear more distinct from one another and from the psychiatric disorders, except for migraine, which was significantly correlated to ADHD, MDD, and Tourette syndrome. We demonstrate that, in the general population, the personality trait neuroticism is significantly correlated with almost every psychiatric disorder and migraine. We also identify significant genetic sharing between disorders and early life cognitive measures (e.g., years of education and college attainment) in the general population, demonstrating positive correlation with several psychiatric disorders (e.g., anorexia nervosa and bipolar disorder) and negative correlation with several neurological phenotypes (e.g., Alzheimer's disease and ischemic stroke), even though the latter are considered to result from specific processes that occur later in life. Extensive simulations were also performed to inform how statistical power, diagnostic misclassification, and phenotypic heterogeneity influence genetic correlations. CONCLUSION The high degree of genetic correlation among many of the psychiatric disorders adds further evidence that their current clinical boundaries do not reflect distinct underlying pathogenic processes, at least on the genetic level. This suggests a deeply interconnected nature for psychiatric disorders, in contrast to neurological disorders, and underscores the need to refine psychiatric diagnostics. Genetically informed analyses may provide important "scaffolding" to support such restructuring of psychiatric nosology, which likely requires incorporating many levels of information. By contrast, we find limited evidence for widespread common genetic risk sharing among neurological disorders or across neurological and psychiatric disorders. We show that both psychiatric and neurological disorders have robust correlations with cognitive and personality measures. Further study is needed to evaluate whether overlapping genetic contributions to psychiatric pathology may influence treatment choices. Ultimately, such developments may pave the way toward reduced heterogeneity and improved diagnosis and treatment of psychiatric disorders

No. 02: The State of Urban Food Insecurity in Southern Africa

The number of people living in urban areas is rising rapidly in Southern Africa. By mid-century, the region is expected to be 60% urban. Rapid urbanization is leading to growing food insecurity in the region’s towns and cities. This paper presents the results of the first ever regional study of the prevalence of food insecurity in Southern Africa. The AFSUN food security household survey was conducted simultaneously in 2008-9 in 11 cities in 8 SADC countries. The results confirm high levels of food insecurity amongst the urban poor in terms of food availability, accessibility, reliability and dietary diversity. The survey provides important insights into the causes of food insecurity and the kinds of households that are most vulnerable to food insecurity. It also shows the heavy reliance of the urban poor on informal food sources and the growing importance of supermarket chains

Differential early subcortical involvement in genetic FTD within the GENFI cohort

Background: Studies have previously shown evidence for presymptomatic cortical atrophy in genetic FTD. Whilst initial investigations have also identified early deep grey matter volume loss, little is known about the extent of subcortical involvement, particularly within subregions, and how this differs between genetic groups. Methods: 480 mutation carriers from the Genetic FTD Initiative (GENFI) were included (198 GRN, 202 C9orf72, 80 MAPT), together with 298 non-carrier cognitively normal controls. Cortical and subcortical volumes of interest were generated using automated parcellation methods on volumetric 3 T T1-weighted MRI scans. Mutation carriers were divided into three disease stages based on their global CDR® plus NACC FTLD score: asymptomatic (0), possibly or mildly symptomatic (0.5) and fully symptomatic (1 or more). Results: In all three groups, subcortical involvement was seen at the CDR 0.5 stage prior to phenoconversion, whereas in the C9orf72 and MAPT mutation carriers there was also involvement at the CDR 0 stage. In the C9orf72 expansion carriers the earliest volume changes were in thalamic subnuclei (particularly pulvinar and lateral geniculate, 9–10%) cerebellum (lobules VIIa-Crus II and VIIIb, 2–3%), hippocampus (particularly presubiculum and CA1, 2–3%), amygdala (all subregions, 2–6%) and hypothalamus (superior tuberal region, 1%). In MAPT mutation carriers changes were seen at CDR 0 in the hippocampus (subiculum, presubiculum and tail, 3–4%) and amygdala (accessory basal and superficial nuclei, 2–4%). GRN mutation carriers showed subcortical differences at CDR 0.5 in the presubiculum of the hippocampus (8%). Conclusions: C9orf72 expansion carriers show the earliest and most widespread changes including the thalamus, basal ganglia and medial temporal lobe. By investigating individual subregions, changes can also be seen at CDR 0 in MAPT mutation carriers within the limbic system. Our results suggest that subcortical brain volumes may be used as markers of neurodegeneration even prior to the onset of prodromal symptoms

Analysis of Shared Heritability in Common Disorders of the Brain

Disorders of the brain can exhibit considerable epidemiological comorbidity and often share symptoms, provoking debate about their etiologic overlap. We quantified the genetic sharing of 25 brain disorders from genome-wide association studies of 265,218 patients and 784,643 control participants and assessed their relationship to 17 phenotypes from 1,191,588 individuals. Psychiatric disorders share common variant risk, whereas neurological disorders appear more distinct from one another and from the psychiatric disorders. We also identified significant sharing between disorders and a number of brain phenotypes, including cognitive measures. Further, we conducted simulations to explore how statistical power, diagnostic misclassification, and phenotypic heterogeneity affect genetic correlations. These results highlight the importance of common genetic variation as a risk factor for brain disorders and the value of heritability-based methods in understanding their etiology