Aerial images and machine learning methods to emulate the late blight severity in potato crops

Assessment of Phytophthora infestans’ incidence and severity are frequently performed based on visual crop inspection, which is a labor-intensive task prone to errors associated with its subjectivity. Therefore, alternative methods to relate disease incidence and severity with changes in crop traits are of great interest. Optical imagery in the visible and near-infrared (VisNIR) can detect changes in crop traits caused by pathogen development. In addition, Unmanned Aerial Vehicles (UAV) with cameras on board have flexible data collection capabilities allowing adjustments considering the trade-off between data throughput and its resolution. This work presents a quantitative prediction of the severity of the disease caused by Phytophthora infestans in potato crops using image processing and machine learning (ML) algorithms such as Random Forests (RF) and Extreme Gradient Boost (XGBoost). The ML algorithms were trained using datasets from multispectral data captured at the canopy level with a UAV carrying a multispectral camera. The results indicate that RF and XGBoost using 11 classes with 18 bands, including vegetation indexes and band features, can predict late blight severity on potato crops with an acceptable accuracy of 81.02% for RF and 74.19% for RF XGBoost

Mechanisms of Inflammation in Neutrophil-Mediated Skin Diseases

Neutrophil-mediated skin diseases, originally named neutrophilic dermatoses (NDs), are a group of conditions due to an altered neutrophil recruitment and activation, characterized by polymorphic cutaneous manifestations with possible internal organ involvement. Although a number of diseases are included in this setting, the two prototypic forms are pyoderma gangrenosum (PG) and Sweet's syndrome (SS) which usually present with skin ulcers and plaque-type lesions, respectively. They have central features significantly overlapping with autoinflammatory conditions which manifest as repeated episodes of tissue inflammation. However, in contrast to appropriate inflammatory responses to insults or to autoimmune disease, there is an absence of identifiable pathogens, autoantibodies, or autoreactive lymphocytes. The recognition of monogenic autoinflammatory diseases which can present with NDs has led to study several genes involved in autoinflammation in NDs. Based on discovering of a number of mutations involving different autoinflammatory genes, neutrophil-mediated skin diseases are nowadays regarded as a spectrum of polygenic autoinflammatory conditions. Although disease mechanisms have not yet been completely elucidated, NDs are recognized as diseases involving dysfunctional cellular signaling mediated by pathways mainly related to inflammasome and IL-1 with the contributory role of IL-17 and other effector molecules. The precise elucidation of the above-mentioned pathologic mechanisms may pave the way to tailored treatments for patients with different neutrophil-mediated skin diseases

The POT1-TPP1 telomere complex is a telomerase processivity factor

Telomeres were originally defined as chromosome caps that prevent the natural ends of linear chromosomes from undergoing deleterious degradation and fusion events. POT1 ( protection of telomeres) protein binds the single-stranded G-rich DNA overhangs at human chromosome ends and suppresses unwanted DNA repair activities. TPP1 is a previously identified binding partner of POT1 that has been proposed to form part of a six-protein shelterin complex at telomeres. Here, the crystal structure of a domain of human TPP1 reveals an oligonucleotide/oligosaccharide-binding fold that is structurally similar to the beta-subunit of the telomere end-binding protein of a ciliated protozoan, suggesting that TPP1 is the missing beta-subunit of human POT1 protein. Telomeric DNA end-binding proteins have generally been found to inhibit rather than stimulate the action of the chromosome end-replicating enzyme, telomerase. In contrast, we find that TPP1 and POT1 form a complex with telomeric DNA that increases the activity and processivity of the human telomerase core enzyme. We propose that POT1 - TPP1 switches from inhibiting telomerase access to the telomere, as a component of shelterin, to serving as a processivity factor for telomerase during telomere extension.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62923/1/nature05454.pd

PRIVATE SAVINGS IN TRANSITION ECONOMIES: ARE THERE TERMS OF TRADE SHOCKS?

The paper examines the impact of terms of trade shocks on private savings in the transition economies after accounting for the effect of other determinants. Economic agents in the transition economies are subject to tight credit constraints which are more pronounced during bad state of nature. Thus, adverse shocks to commodity prices in the world market can force them to reduce savings by a larger amount than they would otherwise have. Empirical analysis using a dynamic panel model and data from twenty one transition economies confirm that most of the determinants of savings identified in the literature also apply to the transition economies. Favorable movements in both the permanent and transitory components of the terms of trade have a significant positive impact on private savings with transitory movements having a larger impact than the permanent component. This reflects the lack of access to foreign borrowing that many of the transition economies have faced during the last decade. Although the impact of terms of trade shocks are found to be asymmetric, the magnitude of the impact appears to be small. The results are robust for alternative estimators, determinants, and country groupings.http://deepblue.lib.umich.edu/bitstream/2027.42/39958/3/wp572.pd

DIMBOA levels in hexaploid Brazilian wheat are not associated with antibiosis against the cereal aphids Rhopalosiphum padi and Sitobion avenae.

The objective of this study was to evaluate the natural levels of the plant defence compound DIMBOA in young leaves of eight hexaploid Brazilian wheat genotypes and the impact of the genotypes upon development of cereal aphids, Rhopalosiphum padi and Sitobion avenae. HPLC Analysis revealed that the DIMBOA levels varied from 5.376 (in BRS Guabiju) to 30.651 mmol/kgFW (in BRS Timbaúva) with two genotypes outperforming Solstice, a UK variety used as reference. Bioassays were conducted to evaluate the development and fecundity of both aphids when grown on the wheat genotypes. Although BRS Guabiju and BRS Timbaúva were among the genotypes showing the highest and lowest susceptibility respectively, against both aphids, no correlation could be found between DIMBOA levels and antibiosis effects. The cultivar BRS 327 that was among the genotypes showing lower intrinsic rate of population increase for the two aphid species. Elucidating the role of secondary metabolites in plant resistance to aphids and the characterisation of the genotypes that allowed reduced aphid development are important steps to achieve a better natural resistance in hexaploid Brazilian wheat