Interfering DC Component, Suppression and Influence to Digital Signal Processing

The article concentrates on effects of a digitized audio signal DC component on a typical A/D converter and its influence on further signal processing. This article analyses reasons of the interfering DC component emergence in the A/D converter. Results of the measurement made on Analog Devices converter are presented. The DC component can adversely affect a series of signal processing algorithms such as algorithms for maintaining stable level of signal (e.g. leveler algorithm). The article examines the possibility of a DC component removal by digital filtering. Attention is focused on the choice of a suitable filter type and its parameters in order to avoid any destruction of a transmitted signal, e.g. due to poor group delay characteristic, or by suppressing low frequencies in the filter

Assessment of Functional AgroBiodiversity in Swedish apple orchards : Field trials and participatory action research

The rate of biodiversity loss has in the last decades increased by rates unseen in the history of the humankind. Agricultural intensification has been one of the main contributors to biodiversity loss. In modern agricultural production, the concentration of land devoted to single crops causes several challenges. In the pest management, specialist crop herbivores have larger area of suitable host plants in monocultures, while the lack of plant diversity reduces environmental opportunities for natural enemies. Synthetic pesticides commonly used for controlling pests over the last decades are gradually losing their effectiveness due to increasing pesticide resistance of insects. Moreover, many pest control technologies have been linked to problems of pollution, high costs, or deregistration of insecticides because of safety concerns. Since January 2014, all fruit growers in EU are required to follow the Integrated Pest Management (IPM) standards, which incorporate a wide array of pest management practices and tactics for long-term pest control. Currently, the IPM still heavily relies on the use of pesticides but tries to promote prevention and alternative environmentally friendly pest management strategies. Functional agrobiodiversity (FAB) has been acknowledged as one of the methods for suppression of the insect pests in agro-ecosystems. The benefits of high diversity on agroecosystems have been discussed for almost decades. However, there is still lack of evidence about the real effects of different FAB practices. Apples are crops with the second highest pesticide use per hectare in Europe after grapes. Organic apple growers have access to less harmful pesticides with lower efficacy that often provide insufficient pest suppression. Therefore, the organic growers need to focus on preventive measures and alternative practices than application of pesticides. This thesis investigates effects of functional agro-biodiversity (FAB) in intensive organic apple production. It aims to understand whether end-user adapted monitoring methods for insect pests and their arthropod natural enemies used by farmers and advisors can support implementation of FAB practices for pest management. Moreover, this work investigates whether flower strips, as one of FAB practices, promote biological pest control in modern apple production. This is achieved through combination of qualitative and quantitative research, participatory research and field trials. This thesis is conducted under the umbrella of the EcoOrchard project that aims to assess how far functional biodiversity can reduce pest damage and pesticide use in organic apple orchards. During the EcoOrchard project, four approaches to FAB were identified. These approaches were adopted and further examined in this thesis. The approaches were interpreted by the growers as an increasing scale of action from observations and avoidance of harming beneficials until active promotion of them by introduction of specific FAB strategies. The participants suggested to create a program for a growing season, to introduce different tasks, and gradually learn through collaboration between research, advisors and growers. The tasks could include a recommended schedule of management practices that promote beneficial insects or recommended dates for use of specific monitoring methods. The economic aspect was of crucial importance for the implementation of FAB practices. This thesis also underlines the importance of monitoring of natural enemies in apple production for participatory development of more resilient and sustainable apple orchards. Better knowledge of biological processes can help growers to change their attitude towards more sustainable production. Functional agrobiodiversity is a complex approach to improve agroecosystems that requires understanding, knowledge and expertise in biological process of specific species and in agricultural production. While the results of the field trials failed to deliver convincing arguments for use the flower strips, as one of FAB practices for pest regulation, the study uncovered several benefits of the monitoring for the growers and the advisors. Further research is required to find plant species with desirable traits that could be applied for FAB in different conditions and for different crops

Electronic Bond Structure of Carbon Nitride Thin Film Deposited by HiPIMS and dc Magnetron Plasma

We report the difference in electronic bond structure and surface chemical property of amorphous carbon nitride (a-CNx) film as a function of N/C which has been deposited by high power impulse magnetron sputtering (HiPIMS) and DC magnetron (dc-MS) plasma. The spectroscopic analyses suggest that the presence of oxide layer is the major cause for the surface charging in the core level peak. The core electron peaks (C1s, N1s and O1s) in x-ray photoelectron spectroscopy (XPS) show higher surface charging in HiPIMS compare to the film deposited by dc-MS plasma. The core peaks are moved gradually toward its virgin position as the etching duration is increased from 1 min to 80 mins. The films deposited by HiPIMS retain a higher N/C ratio following ion etching as compared to those deposited by DC magnetron sputtering suggesting denser films with a higher degree of cross-linking

A novel crossed-molecular-beam experiment for investigating reactions of state- and conformationally selected strong-field-seeking molecules

The structure and quantum state of the reactants have a profound impact on the kinetics and dynamics of chemical reactions. Over the past years, significant advances have been made in the control and manipulation of molecules with external electric and magnetic fields in molecular-beam experiments for investigations of their state-, structure- and energy-specific chemical reactivity. Whereas studies for neutrals have so far mainly focused on weak-field-seeking species, we report here progress towards investigating reactions of strong-field-seeking molecules by introducing a novel crossed-molecular-beam experiment featuring an electrostatic deflector. The new setup enables the characterisation of state- and geometry-specific effects in reactions under single-collision conditions. As a proof of principle, we present results on the chemi-ionisation reaction of metastable neon atoms with rotationally state-selected carbonyl sulfide (OCS) molecules and show that the branching ratio between the Penning and dissociative ionisation pathways strongly depends on the initial rotational state of OCS.Comment: 8 pages, 6 figure

Development and characterization of high-repetition-rate sources for supersonic beams of fluorine radicals

We present and compare two high-pressure, high-repetition-rate electric-discharge sources for the generation of supersonic beams of fluorine radicals. The sources are based on dielectric-barrier-discharge (DBD) and plate-discharge units attached to a pulsed solenoid valve. The corrosion-resistant discharge sources were operated with fluorine gas seeded in helium up to backing pressures as high as 30 bars. We employed a (3 + 1) resonance-enhanced multiphoton ionization combined with velocity-map imaging for the optimization, characterization, and comparison of the fluorine beams. Additionally, universal femtosecond-laser-ionization detection was used for the characterization of the discharge sources at experimental repetition rates up to 200 Hz. Our results show that the plate discharge is more efficient in F2 dissociation than the DBD by a factor between 8 and 9, whereas the DBD produces internally colder fluorine radicals

Impact of Intercollegiate Athletics on Undergraduate Enrollment at a Small, Faith-Based Institution

Based on previous research, it is apparent many National Collegiate Athletic Association (NCAA) Division I institutions benefit from the existence of and success in intercollegiate athletics. However, few studies have researched the impact of intercollegiate athletics at National Association of Intercollegiate Athletics (NAIA) institutions. Therefore, the purpose of this study was to investigate the effect of intercollegiate athletics at a small, faith-based institution affiliated with the NAIA. More specifically, does success in or the existence of intercollegiate athletics have an effect on students’ decisions to enroll at this institution? Findings indicate the majority of freshmen student participants, including many intercollegiate athletes, were not considerably influenced by the existence of intercollegiate athletics or the existence of successful intercollegiate athletics when deciding to attend the institution. These findings indicate the need for similar institutions to reevaluate the importance placed on and benefits derived from intercollegiate athletics

Analysis of the Release Characteristics of Cu-Treated Antimicrobial Implant Surfaces Using Atomic Absorption Spectrometry

New developments of antimicrobial implant surfaces doped with copper (Cu) ions may minimize the risk of implant-associated infections. However, experimental evaluation of the Cu release is influenced by various test parameters. The aim of our study was to evaluate the Cu release characteristics in vitro according to the storage fluid and surface roughness. Plasma immersion ion implantation of Cu (Cu-PIII) and pulsed magnetron sputtering process of a titanium copper film (Ti-Cu) were applied to titanium alloy (Ti6Al4V) samples with different surface finishing of the implant material (polished, hydroxyapatite and corundum blasted). The samples were submersed into either double-distilled water, human serum, or cell culture medium. Subsequently, the Cu concentration in the supernatant was measured using atomic absorption spectrometry. The test fluid as well as the surface roughness can alter the Cu release significantly, whereby the highest Cu release was determined for samples with corundum-blasted surfaces stored in cell medium

Conformer-specific polar cycloaddition of dibromobutadiene with trapped propene ions

Identifying a concerted or stepwise mechanism in Diels-Alder reactions is experimentally challenging. Here the authors demonstrate the coexistence of both mechanisms in the reaction of 2,3-dibromobuta-1,3-diene with propene ions, using a conformationally controlled molecular beam reacting with trapped ions and ab initio computations Diels-Alder cycloadditions are efficient routes for the synthesis of cyclic organic compounds. There has been a long-standing discussion whether these reactions proceed via stepwise or concerted mechanisms. Here, we adopt an experimental approach to explore the mechanism of the model polar cycloaddition of 2,3-dibromo-1,3-butadiene with propene ions by probing its conformational specificities in the entrance channel under single-collision conditions in the gas phase. Combining a conformationally controlled molecular beam with trapped ions, we find that both conformers of the diene, gauche and s-trans, are reactive with capture-limited reaction rates. Aided by quantum-chemical and quantum-capture calculations, this finding is rationalised by a simultaneous competition of concerted and stepwise reaction pathways, revealing an interesting mechanistic borderline case

Electrochemical lossy mode resonance for the detection of manganese ions

In this work we propose electrochemical lossy mode resonance (eLMR) as a powerful method for the detection of manganese (Mn) ions. The sensor is based on a simple planar waveguide (sodasingle bondlime glass coverslip) coated with a thin layer of indium tin oxide (ITO) to obtain an optical resonance effect. Simultaneously, the ITO layer served as the working electrode in the cathodic stripping voltammetry (CSV) of Mn. The eLMR sensor is capable of simultaneously performing electrochemical (EC) and optical measurements, specifically lossy mode resonance (LMR), to monitor the growth of the adsorbed Mn layer on the ITO electrode and the electrochemically modulated diffusion layer. For Mn2+ ions, a limit of detection (LoD) of 1.26 ppb has been demonstrated using the EC method, whereas the optical method exhibited a LoD of 67.76 ppb. The results obtained indicate significant potential for application in molecular electrochemistry and studies focused on electrified interfaces.This work was supported in part by the Agencia Estatal de Investigación (AEI) from the Spanish Ministry of Economy and Competitiveness (PID2019-106070RB-I00 and PID2022-137437OB-I00 research funds), by the Government of Navarre through its projects with references: and PC058-059 EleSpray and 0011-1365-2022-000241, and by the pre-doctoral research grant of the Public University of Navarra. The authors also acknowledge financial support received from the National Centre for Research and Development, Poland, grant No. TECHMATSTRATEG- III/0042/2019, as well as the Czech Science Foundation Agency through the project 21-05030K and the National Science Centre (NCN), Poland, as part of the 2020/02/Y/ST8/00030 project. Open access funding provided by Universidad Pública de Navarra