Inside Out: Transforming Images of Lab-Grown Plants for Machine Learning Applications in Agriculture

Machine learning tasks often require a significant amount of training data for the resultant network to perform suitably for a given problem in any domain. In agriculture, dataset sizes are further limited by phenotypical differences between two plants of the same genotype, often as a result of differing growing conditions. Synthetically-augmented datasets have shown promise in improving existing models when real data is not available. In this paper, we employ a contrastive unpaired translation (CUT) generative adversarial network (GAN) and simple image processing techniques to translate indoor plant images to appear as field images. While we train our network to translate an image containing only a single plant, we show that our method is easily extendable to produce multiple-plant field images. Furthermore, we use our synthetic multi-plant images to train several YoloV5 nano object detection models to perform the task of plant detection and measure the accuracy of the model on real field data images. Including training data generated by the CUT-GAN leads to better plant detection performance compared to a network trained solely on real data.Comment: 35 pages, 23 figure

The prevalence of human trichuriasis in Asia: a systematic review and meta‑analysis

Trichuriasis is one of the most common soil-transmitted helminth (STH) infections, affecting populations globally. The condition is particularly prevalent in tropical and subtropical areas with low levels of sanitation and poor living conditions. The objective of this systematic review and meta-analysis was to evaluate the prevalence of Trichuris trichiura infection in Asia at the country and region level. Multiple databases/academic search engines (Web of Science, PubMed, ProQuest, Scopus, and Google Scholar) were searched for literature on T. trichiura prevalence in Asia published through January 2021. Pooled prevalence was determined using the meta-package in R (version 3.6.1). Out of 13,836 articles, 226 studies (5,439,500 individuals) from 26 countries met the inclusion criteria. Of the 226 studies, 151 were community-based studies that included individuals across the age spectrum, while 75 studies focused on school children (typically in the 5–16 years age range). The overall T. trichiura pooled prevalence was 15.3% (95% CI: 12.4–19.1%), with a pooled prevalence of 13.3% (95% CI: 10.0–17.1%) for the community studies and 20.9% (95% CI: 14.7–27.9%) for the studies only including school children. For studies including all age groups, individuals in the 1–15 years age group had the highest pooled prevalence at 23.4% (95% CI: 1.7–49.4%). There was a significant difference found in overall pooled prevalence by sex (p < 0.001) and community type (rural versus urban) (p < 0.001). Although prevalence appears to be decreasing, study findings suggest that T. trichiura infection continues to be a public health problem in Asia. Therefore, control programs focused on at-risk individuals in endemic areas are needed

Ibrutinib-A double-edge sword in cancer and autoimmune disorders

Targeted therapies have appeared as new treatment options for several disease types, including cancer and autoimmune disorders. Of several targets, tyrosine kinases (TKs) are among the most promising. Overexpression of TKs provides a target for novel therapeutic agents, including small molecule inhibitors of tyrosine kinases (TKI). Ibrutinib (PCI-32765) is a TKI of Bruton’s tyrosine kinase (Btk), a key kinase of the B-cell receptor signaling pathway that plays a significant role in the proliferation, differentiation and survival of B cells. In addition to inhibitory effects, recent studies have shown that ibrutinib has multiple immunomodulatory effects. It binds covalently to IL-2 inducible tyrosine kinase (Itk) in T lymphocytes and suppresses the survival of T-helper (Th) 2 cells. This changes the balance of Th1/Th2 cells toward Th1 subset, which are the main immune cells targeting tumor cells. The dual activity of ibrutinib has paid a great attention and several studies are evaluating the anti-tumor and immunomodulatory effects in cancer, autoimmune disorders and infectious diseases. In this article we review the inhibitory and immunomodulatory effects of ibrutinib in B-cell malignancies, autoimmune diseases and infections, as well as the communication between the Ror1 receptor tyrosine kinase and BCR and effects of ibrutinib on this crosstalk.CLL Global Research FoundationManuscrip

Design, characterisation, and numerical simulation of double heterojunction bipolar transistors for microwave power applications

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN047135 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Empirical low-field mobility model for III-V compounds applicable in device simulation codes

A Caughey–Thomas-like mobility model with temperature and composition dependent coefficients is used in this work to describe the dependence of electron and hole mobilities on temperature, doping concentration, and alloy composition. Appropriate parameter sets are given for a large number of III–V binary and ternary compounds, including: GaAs, InP, InAs, AlAs, GaP, Al0.3Ga0.7As, In0.52Al0.48As, In0.53Ga0.47As, and In0.49Ga0.51P. Additionally, physically justifiable interpolation schemes are suggested to find the mobilities of various ternary and quaternary compounds (such as AlxGa1−xAs, In1−xGaxP, In1−xGaxAs, In1−xAlxAs, and In1−xGaxAsyP1−y) in the entire range of composition. The models are compared with numerous measured Hall data in the literature and very good agreement is observed. The limitations of the present model are also discussed. The results of this work should be extremely useful in device simulation packages, which are currently lacking a reliable mobility model for the above materials. © 2000 American Institute of Physics

Planar self-aligned microwave InGaP/GaAs HBTs using He+/O+ implant isolation

The fabrication results of InGaP/GaAs HBTs using a planar technology are presented. The device isolation was achieved by ion implantation using oxygen and hydrogen ions. However, this combination of ions produced a new problem related to carbon acceptor passivation inside the base layer of the HBT. To avoid this situation, hydrogen was replaced with heavier and thus less diffusive helium ions. Measured characteristics of the He+/O+ implanted HBTs show no variation of current gain with device geometry and suggest that the problem related to passivation of carbon accepters inside the base has completely been resolved. The fabricated InGaP/GaAs microwave HBTs show an almost uniform cut-off frequency, fT, of about 35 GHz for an emitter area of 8×10 μm2

Reliability investigation of implanted microwave InGaP/GaAs HBTs

In this paper, we report the fabrication and characterisation of C-doped InGaP/GaAsmicrowaveHBTs using a planar self-aligned technology based on O+/H+ or O+/He+ implant isolation schemes. We observed current gain variations with emitter/base geometries in the H+implantedHBTs while no such variation was observed in the He+implanted transistors. This latter phenomenon is characterised by a current gain increase in the smaller device and this was attributed to a decrease of the hole concentration in the base, caused by the formation of CH complexes in the C-doped GaAs base region. We therefore recommend the use of O+/He+ implant scheme for the fabrication of reliable high performance C-doped base HBTs

Numerical modelling of AlGaAs/GaAs and InGaP/GaAs single and double HBTs

The dc characteristics of a graded AlGaAs/GaAs single HBT (SHBT) and an abrupt InGaP/GaAs double HBT (DHBT) are studied using a thermionic-field emission boundary condition model. The model incorporates tunnelling and thermionic emission into a one-dimensional drift-diffusion numerical scheme and accounts for carrier degeneracy and bandgap narrowing. To our best knowledge, this is the first ever reported numerical analysis of InGaP/GaAs HBTs. A variety of existing data from different sources is analysed to find the best theoretical/empirical relations for the bandgap and transport related parameters of In1-xGaxP. The room temperature calculated Gummel plots and common-emitter output characteristics are compared to the experimentally measured ones and a good fit is observed between the two results. Finally, the simulated variation of current gain with temperature in various devices will be demonstrated

DC characterisation of HBTs using the observed kink effect on the base current

Large parasitic series resistances of the heterostructure bipolar transistors are shown to cause a sharp rise in the base current of the Gummel plot at high current levels. This effect is analysed and attributed to a forward-biased base–collector junction due to the large voltage drop across the collector series resistance of the device. The occurrence of this effect results in a severe reduction in current gain of the device at high current levels. A DC Ebers–Moll model is presented with all the parameters extracted from DC characterisation of the HBT, and an excellent fit between the model and experimental data is obtained. The method can be used to determine the base, collector and emitter series resistances of the bipolar transistors for DC applications. Finally, the effect of temperature on the onset of this effect is demonstrated