A comparative study on the functional response of Wolbachia-infected and uninfected forms of the parasitoid wasp Trichogramma brassicae

Trichogramma species (Hymenoptera: Trichogrammatidae) are haplo-diploid egg parasitoids that are frequently used as biological control agents against lepidopteran pests. These wasps display two reproductive modes, including arrhenotoky (bisexuality) and thelytoky (unisexuality). Thelytokous forms are often associated with the presence of endosymbiotic Wolbachia bacteria. The use of thelytokous wasps has long been considered as a way to enhance the efficacy of biological control. The present study investigates the potential of a thelytokous Wolbachiainfected and an arrhenotokous uninfected Trichogramma brassicae Bezdenko strain as inundative biocontrol agents by evaluating their functional response towards different egg densities of the factitious host, the Angoumois grain moth, Sitotroga cerealella (Olivier) (Lepidoptera: Gelechiidae). The results revealed a type II functional response for both strains in which parasitism efficiency decreases with host egg density because of an increasing host handling time. A model with an indicator variable was used to compare the parameters of Holling’s disc equation in different data sets. It was demonstrated that the two strains did not differ in host attack rate. However, the Wolbachia-infected strain did have an increased host handling time when compared to the bisexual strain. Some applied aspects of the findings are discusse

Wireless structural health monitoring (SHM) system for damage detection using ultrasonic guided waveform response

This paper presents an improved version of a wireless device embedded with a smart PZT sensor to detect flaws and structural defects on selected investigated structure. Smart PZT sensors were used as an actuator and sensor, coupled with two XBee's and one signal generator IC chip. Programme execution on transmitting and receiving the ultrasonic guided wave via the PZT sensor had been written in MATLAB. The developed source code is basically to receive serial data from one Xbee to another remote Xbee attached to the investigated structural system. The refined waveform response is utilised for prognosis of the true structural status. The 4-mm simulated holed into one of the aluminium structural plate is benchmarked with its pristine condition in validating the effectiveness of the developed SHM wireless module. Results showed that the wave is more even in non-defected area and disrupted in affected area. Ultrasonic waves increase continuously for non-destructive evaluation and structural health monitoring in various structural applications because the guided wave can propagate long distances and reach difficult-to-access regions; for inspecting porous and some non-porous materials ultrasonic waves attenuate fast and are very useful. Recent advances in ultrasonic wave application model and results are discussed in this paper

Modified Heider Balance on Sparse Random Networks

The lack of signed random networks in standard balance studies has prompted us to extend the Hamiltonian of the standard balance model. Random networks with tunable parameters are suitable for better understanding the behavior of standard balance as an underlying dynamics. Moreover, the standard balance model in its original form does not allow preserving tensed triads in the network. Therefore, the thermal behavior of the balance model has been investigated on a fully connected signed network recently. It has been shown that the model undergoes an abrupt phase transition with temperature. Considering these two issues together, we examine the thermal behavior of the structural balance model defined on Erd\H{o}s-R\'enyi random networks. We provide a Mean-Field solution for the model. We observe a first-order phase transition with temperature, for both the sparse and densely connected networks. We detect two transition temperatures, $T_{cold}$ and $T_{hot}$, characterizing a hysteresis loop. We find that with increasing the network sparsity, both $T_{cold}$ and $T_{hot}$ decrease. But the slope of decreasing $T_{hot}$ with sparsity is larger than the slope of decreasing $T_{cold}$. Hence, the hysteresis region gets narrower, until, in a certain sparsity, it disappears. We provide a phase diagram in the temperature-tie density plane to observe the meta-stable/coexistence region behavior more accurately. Then we justify our Mean-Field results with a series of Monte-Carlo simulations.Comment: 10 Pages, 5 Figure

Damage identification using wireless structural health monitoring system through smart sensor application

Delamination, disbanding, void, low impact resistance and visible internal damage are some of damages uniquely found in the structure. Any damage found on the structure require repair. The inspection need to be done to detect the damage on structure before the structure can be repaired. Non-Destructive Inspection (NDI) and Structural health monitoring (SHM) concept were used to detect flaws from structures. But the SHM differs from NDT which the system used to monitor the integrity of mechanical structures in a continuous and independent way. SHM helps to reduce financial cost for maintenance. SHM can monitor this situation in active and passive states, either by online or offline monitoring. The use of SHM is to augment the NDI application and not to replace it. This paper presents the damage identification technique by using the improved design of wireless structural health monitoring system. Smart PZT sensors were used as an actuator and receiver, coupled with two XBee’s and two Ardiuno as signal generator and signal receiver. Program execution on transmitting and receiving the ultrasonic guided wave via the PZT sensor had been written in Makerplot. The acquired results showed that the wave is more even in non-defected area and disrupted in affected area

CSNL: A cost-sensitive non-linear decision tree algorithm

This article presents a new decision tree learning algorithm called CSNL that induces Cost-Sensitive Non-Linear decision trees. The algorithm is based on the hypothesis that nonlinear decision nodes provide a better basis than axis-parallel decision nodes and utilizes discriminant analysis to construct nonlinear decision trees that take account of costs of misclassification. The performance of the algorithm is evaluated by applying it to seventeen datasets and the results are compared with those obtained by two well known cost-sensitive algorithms, ICET and MetaCost, which generate multiple trees to obtain some of the best results to date. The results show that CSNL performs at least as well, if not better than these algorithms, in more than twelve of the datasets and is considerably faster. The use of bagging with CSNL further enhances its performance showing the significant benefits of using nonlinear decision nodes. The performance of the algorithm is evaluated by applying it to seventeen data sets and the results are compared with those obtained by two well known cost-sensitive algorithms, ICET and MetaCost, which generate multiple trees to obtain some of the best results to date. The results show that CSNL performs at least as well, if not better than these algorithms, in more than twelve of the data sets and is considerably faster. The use of bagging with CSNL further enhances its performance showing the significant benefits of using non-linear decision nodes

Prion protein monoclonal antibody (PRN100) therapy for Creutzfeldt–Jakob disease: evaluation of a first-in-human treatment programme

Background: Human prion diseases, including Creutzfeldt–Jakob disease (CJD), are rapidly progressive, invariably fatal neurodegenerative conditions with no effective therapies. Their pathogenesis involves the obligate recruitment of cellular prion protein (PrPC) into self-propagating multimeric assemblies or prions. Preclinical studies have firmly validated the targeting of PrPC as a therapeutic strategy. We aimed to evaluate a first-in-human treatment programme using an anti-PrPC monoclonal antibody under a Specials Licence. Methods: We generated a fully humanised anti-PrPC monoclonal antibody (an IgG4κ isotype; PRN100) for human use. We offered treatment with PRN100 to six patients with a clinical diagnosis of probable CJD who were not in the terminal disease stages at the point of first assessment and who were able to readily travel to the University College London Hospital (UCLH) Clinical Research Facility, London, UK, for treatment. After titration (1 mg/kg and 10 mg/kg at 48-h intervals), patients were treated with 80–120 mg/kg of intravenous PRN100 every 2 weeks until death or withdrawal from the programme, or until the supply of PRN100 was exhausted, and closely monitored for evidence of adverse effects. Disease progression was assessed by use of the Medical Research Council (MRC) Prion Disease Rating Scale, Motor Scale, and Cognitive Scale, and compared with that of untreated natural history controls (matched for disease severity, subtype, and PRNP codon 129 genotype) recruited between Oct 1, 2008, and July 31, 2018, from the National Prion Monitoring Cohort study. Autopsies were done in two patients and findings were compared with those from untreated natural history controls. Findings: We treated six patients (two men; four women) with CJD for 7–260 days at UCLH between Oct 9, 2018, and July 31, 2019. Repeated intravenous dosing of PRN100 was well tolerated and reached the target CSF drug concentration (50 nM) in four patients after 22–70 days; no clinically significant adverse reactions were seen. All patients showed progressive neurological decline on serial assessments with the MRC Scales. Neuropathological examination was done in two patients (patients 2 and 3) and showed no evidence of cytotoxicity. Patient 2, who was treated for 140 days, had the longest clinical duration we have yet documented for iatrogenic CJD and showed patterns of disease-associated PrP that differed from untreated patients with CJD, consistent with drug effects. Patient 3, who had sporadic CJD and only received one therapeutic dose of 80 mg/kg, had weak PrP synaptic labelling in the periventricular regions, which was not a feature of untreated patients with sporadic CJD. Brain tissue-bound drug concentrations across multiple regions in patient 2 ranged from 9·9 μg per g of tissue (SD 0·3) in the thalamus to 27·4 μg per g of tissue (1·5) in the basal ganglia (equivalent to 66–182 nM). Interpretation: Our academic-led programme delivered what is, to our knowledge, the first rationally designed experimental treatment for human prion disease to a small number of patients with CJD. The treatment appeared to be safe and reached encouraging CSF and brain tissue concentrations. These findings justify the need for formal efficacy trials in patients with CJD at the earliest possible clinical stages and as prophylaxis in those at risk of prion disease due to PRNP mutations or prion exposure. Funding: The Cure CJD Campaign, the National Institute for Health Research UCLH Biomedical Research Centre, the Jon Moulton Charitable Trust, and the UK MRC

Gas Accretion and Star Formation Rates

Cosmological numerical simulations of galaxy evolution show that accretion of metal-poor gas from the cosmic web drives the star formation in galaxy disks. Unfortunately, the observational support for this theoretical prediction is still indirect, and modeling and analysis are required to identify hints as actual signs of star-formation feeding from metal-poor gas accretion. Thus, a meticulous interpretation of the observations is crucial, and this observational review begins with a simple theoretical description of the physical process and the key ingredients it involves, including the properties of the accreted gas and of the star-formation that it induces. A number of observations pointing out the connection between metal-poor gas accretion and star-formation are analyzed, specifically, the short gas consumption time-scale compared to the age of the stellar populations, the fundamental metallicity relationship, the relationship between disk morphology and gas metallicity, the existence of metallicity drops in starbursts of star-forming galaxies, the so-called G dwarf problem, the existence of a minimum metallicity for the star-forming gas in the local universe, the origin of the alpha-enhanced gas forming stars in the local universe, the metallicity of the quiescent BCDs, and the direct measurements of gas accretion onto galaxies. A final section discusses intrinsic difficulties to obtain direct observational evidence, and points out alternative observational pathways to further consolidate the current ideas.Comment: Invited review to appear in Gas Accretion onto Galaxies, Astrophysics and Space Science Library, eds. A. J. Fox & R. Dav\'e, to be published by Springe