A discussion of the market and policy failures associated with the adoption of herbicide-tolerant crops

Weed control in the U.S. Midwest has become increasingly herbicide-centric due to the adoption of herbicide-tolerant (HT) crops in the 1990s. The scarcity of the use of integrated weed management (IWM) practices, including biological and mechanical controls, is concerning for two reasons. First, herbicides create negative health and environmental externalities. Second, weed resistance to some herbicides is increasing, which creates incentives to use additional herbicides. However, it seems certain that weeds will develop resistance to those herbicides as well, so applying “herbicide upon herbicide” is socially problematic. In this context, we develop an economic framework to clarify the interplay among the different market failures that either contribute to the herbicidal “lock-in” or make it problematic. We then analyze the evidence for and perceptions of these market failures based on twenty-four semistructured interviews with farmers and experts conducted in 2017, as well as discussions in the academic literature. To this end, we put into perspective the possible self-reinforcing effects in the adoption path of HT crops, such as increasing farm size, changes in farm equipment, increasing incentives for simplified crop rotations, and the loss of practical knowledge of IWM practices

Hybrid use of a robotic welding system in remote laser separation of thin-sheet Al casings for the recycling of battery packs

Robotic systems equipped with high-power laser sources are often employed for the production of battery packs for the electric mobility sector. Considering the strive toward a circular manufacturing economy, there is great interest in the possibility of reconfiguring such equipment for dismantling operations. The present study explores the hybrid use of a robotized fiber laser welding system, adapting its scope from joining of battery casings toward the separation of the same thin Al sheets, enabling the recycling of the internal cells of the battery pack. Process feasibility is assessed by tailoring the beam size as well as exploiting dynamic beam oscillation to perform the separation process. Dynamic beam oscillation allows us to obtain a smaller kerf width and greater process stability with respect to linear trajectories with larger beam sizes. The damage to underlying cells of the separation region was also assessed on different materials (Al, Ni-plated steel, and Cu). Greater surface modifications and higher peak temperatures (in excess of 800 °C) were recorded when employing dynamic beam oscillation with respect to linear trajectories. This research demonstrates a pathway for reutilization of the existing technological systems for a circular and sustainable production chain in the e-mobility sector

The Planck-LFI flight model composite waveguides

The Low Frequency Instrument on board the PLANCK satellite is designed to give the most accurate map ever of the CMB anisotropy of the whole sky over a broad frequency band spanning 27 to 77 GHz. It is made of an array of 22 pseudo-correlation radiometers, composed of 11 actively cooled (20 K) Front End Modules (FEMs), and 11 Back End Modules (BEMs) at 300K. The connection between the two parts is made with rectangular Wave Guides. Considerations of different nature (thermal, electromagnetic and mechanical), imposed stringent requirements on the WGs characteristics and drove their design. From the thermal point of view, the WG should guarantee good insulation between the FEM and the BEM sections to avoid overloading the cryocooler. On the other hand it is essential that the signals do not undergo excessive attenuation through the WG. Finally, given the different positions of the FEM modules behind the focal surface and the mechanical constraints given by the surrounding structures, different mechanical designs were necessary. A composite configuration of Stainless Steel and Copper was selected to satisfy all the requirements. Given the complex shape and the considerable length (about 1.5-2 m), manufacturing and testing the WGs was a challenge. This work deals with the development of the LFI WGs, including the choice of the final configuration and of the fabrication process. It also describes the testing procedure adopted to fully characterize these components from the electromagnetic point of view and the space qualification process they underwent. Results obtained during the test campaign are reported and compared with the stringent requirements. The performance of the LFI WGs is in line with requirements, and the WGs were successfully space qualified.Comment: this paper is part of the Prelaunch status LFI papers published on JINST: http://www.iop.org/EJ/journal/-page=extra.proc5/jins

Histologic findings at diagnosis as predictive markers of clinical outcome in pediatric ulcerative colitis

Background: The role of histological inflammation at diagnosis as a possible prognostic factor for disease course has not been investigated. Aims: To assess whether histologic findings at diagnosis could predict clinical outcomes and evaluate the association between clinical, biochemical, endoscopic, and histological findings. Methods: Prospective single-center study including pediatric UC patients with a minimum follow-up of 12 months. The association between histological activity (Nancy Index, Robarts Histopathology Index, and Geboes Score) and 12-month clinical outcomes was evaluated. Secondarily, we assessed the correlation between histological scores and endoscopic and inflammatory markers at the diagnosis. Inter-observer agreement for histologic and endoscopic scores was also evaluated. Results: Forty-nine UC patients were included. No association was found between 1-year clinical relapse and the three histological indices at diagnosis (p > 0.05). Good concordance was found among the three histological scores (p < 0.001), and between all histological and endoscopic indices (p < 0.05). No correlation was found between histologic scores and serum inflammatory markers. Inter-observer agreement was good for eMayo, Nancy and Robarts score (k = 0.71, k = 0.74 and k = 0.68, respectively) and moderate for Geboes (k = 0.46). Conclusions: Histological findings at diagnosis cannot be used as a predictor of the disease course. The three histological scores used in routine clinical practice show an overall good correlation and reliability

Planck-LFI radiometers' spectral response

The Low Frequency Instrument (LFI) is an array of pseudo-correlation radiometers on board the Planck satellite, the ESA mission dedicated to precision measurements of the Cosmic Microwave Background. The LFI covers three bands centred at 30, 44 and 70 GHz, with a goal bandwidth of 20% of the central frequency. The characterization of the broadband frequency response of each radiometer is necessary to understand and correct for systematic effects, particularly those related to foreground residuals and polarization measurements. In this paper we present the measured band shape of all the LFI channels and discuss the methods adopted for their estimation. The spectral characterization of each radiometer was obtained by combining the measured spectral response of individual units through a dedicated RF model of the LFI receiver scheme. As a consistency check, we also attempted end-to-end spectral measurements of the integrated radiometer chain in a cryogenic chamber. However, due to systematic effects in the measurement setup, only qualitative results were obtained from these tests. The measured LFI bandpasses exhibit a moderate level of ripple, compatible with the instrument scientific requirements.Comment: 16 pages, 9 figures, this paper is part of the Prelaunch status LFI papers published on JINST: http://www.iop.org/EJ/journal/-page=extra.proc5/jins

Methodological comparison of laser stripping solutions with contemporary pulsed lasers for e-drive copper hairpins

The electric drives used in traction applications employ conventionally pure Cu bars bent to the required form, inserted in the stator and welded by a laser at the extremities. These extremities, which are referred to as Cu hairpins, should be stripped off from the electrically isolating polymeric enamel. Laser stripping is industrially used to remove the enamel from the Cu surface. Pulsed wave lasers are employed for the purpose with a large variety of solutions industrially available to the end users. The peculiar process may give way to material removal by surface heating for instance using infrared radiation (IR) or ultraviolet (UV) lasers or an indirect material expulsion via near-infrared (NIR) sources. Accordingly all major laser sources, namely CO2, active fiber, active disk, and Nd:YAG at different wavelengths, may be used for the purpose. Such laser sources possess very different characteristics regarding the pulse durations, power levels, and beam diameters. As newer laser system solutions are made available, the need for methods and experimental procedures to compare the process performance also increases. This work compares 7 different hairpin stripping solutions based on contemporary pulsed laser sources along with a detailed comparative analysis method. Initially, the 7 laser sources are used for hairpin stripping. The process quality is analyzed through surface morphology, chemistry, and the mechanical strength upon laser welding. Productivity and efficiency indicators are collected. Using the collected data, the work proposes system configurations for three different scenarios prioritizing quality, productivity, and cost

Flaring Behavior of the Quasar 3C~454.3 across the Electromagnetic Spectrum

We analyze the behavior of the parsec-scale jet of the quasar 3C~454.3 during pronounced flaring activity in 2005-2008. Three major disturbances propagated down the jet along different trajectories with Lorentz factors $\Gamma>$10. The disturbances show a clear connection with millimeter-wave outbursts, in 2005 May/June, 2007 July, and 2007 December. High-amplitude optical events in the $R$-band light curve precede peaks of the millimeter-wave outbursts by 15-50 days. Each optical outburst is accompanied by an increase in X-ray activity. We associate the optical outbursts with propagation of the superluminal knots and derive the location of sites of energy dissipation in the form of radiation. The most prominent and long-lasting of these, in 2005 May, occurred closer to the black hole, while the outbursts with a shorter duration in 2005 Autumn and in 2007 might be connected with the passage of a disturbance through the millimeter-wave core of the jet. The optical outbursts, which coincide with the passage of superluminal radio knots through the core, are accompanied by systematic rotation of the position angle of optical linear polarization. Such rotation appears to be a common feature during the early stages of flares in blazars. We find correlations between optical variations and those at X-ray and $\gamma$-ray energies. We conclude that the emergence of a superluminal knot from the core yields a series of optical and high-energy outbursts, and that the mm-wave core lies at the end of the jet's acceleration and collimation zone.Comment: 57 pages, 23 figures, 8 tables (submitted to ApJ

The linearity response of the Planck-LFI flight model receivers

In this paper we discuss the linearity response of the Planck-LFI receivers, with particular reference to signal compression measured on the 30 and 44 GHz channels. In the article we discuss the various sources of compression and present a model that accurately describes data measured during tests performed with individual radiomeric chains. After discussing test results we present the best parameter set representing the receiver response and discuss the impact of non linearity on in-flight calibration, which is shown to be negligible.Comment: this paper is part of the Prelaunch status LFI papers published on JINST: http://www.iop.org/EJ/journal/-page=extra.proc5/jinst; This is an author-created, un-copyedited version of an article accepted for publication in JINST. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The definitive publisher authenticated version is available online at 10.1088/1748-0221/4/12/T12011