Far-field mapping of the longitudinal magnetic and electric optical fields

In this letter, we demonstrate the experimental mapping of the longitudinal magnetic and electric optical fields with a standard scanning microscope that involves a high numerical aperture far-field objective. The imaging concept relies upon the insertion of an azimuthal or a radial polarizer within the detection path of the microscope which acts as an optical electromagnetic filter aimed at transmitting selectively to the detector the signal from the magnetic or electric longitudinal fields present in the detection volume, respectively. The resulting system is thus versatile, non invasive, of high resolution, and shows high detection efficiencies. Magnetic optical properties of physical and biological micro and nano-structures may thus be revealed with a far-field microscope

Reintroduction of Bison (\u3cem\u3eBison bison\u3c/em\u3e) on Reservations in South Dakota: Four Case Studies

This research explored and documented issues of sustainability associated with the reintroduction of bison in four different bison herds on Reservations in South Dakota. The four herds were managed by: a tribal family cooperative, an individual tribal member, a tribal university and a tribal fish and wildlife agency. The objectives were to identify management practices associated with the sustainability of bison introduction by American Indians; to explore the role of American Indian culture in the management of bison for sustainability; and to investigate rangeland criteria that could be used to measure sustainability of bison reintroduced by American Indians. This project used a holistic, descriptive approach including interviews, coding, and analysis to build themes among the four case studies. The four case study interviews focused on overall management: general practices; environmental issues; economic concerns and cultural issues associated with tribal bison reintroduction. The case study also included rangeland data collection and analysis to determine both soil and plant quality. Soil quality criteria included organic matter, aggregate stability, water content, and chemical analyses. Plant criteria included measures of crude protein, acid detergent fiber, neutral detergent fiber, dry matter production and a species inventory. Each site had replicated plots in shoulder-, mid-, and toe-slope positions with the mid-slope positions having grazed and ungrazed treatments. Common themes that emerged from the interviews included: a hands-off management style; concern for the health and interactions of the land, animals and people; and a de-emphasis of the importance of economics. All four managers acknowledged the importance of cultural traditions and three expressed a deep cultural and spiritual connection to the bison. Results from the soil and plant quality analysis indicated that rangeland conditions were equal to or better than those measured on other grasslands in South Dakota or reported in the literature for mixed-grass prairie. Soil chemical and physical properties supported a diverse plant population with adequate levels of nutrition for bison. The Lakota philosophy of Mitakuye Oyasin, ―all my relatives‖, reflects the Native understanding of connectedness of all aspects of life. This holistic understanding was present in the approach of all four bison managers. Integrating the qualitative and quantitative data from these case studies offers valuable insight into the challenges, successes and unique perspectives of a diverse group of herd managers and contemporary Native leaders of tribal bison reintroduction

L'accompagnement spirituel infirmier de la personne en fin de vie en détresse spirituelle

Cette revue de la littérature, réalisée dans le but d’obtenir le Bachelor en soins infirmiers, a pour but de mettre en évidence les compétences infirmières nécessaires à l’accompagnement de la personne en fin de vie en situation de détresse spirituelle. La maladie grave, et à plus forte raison la perspective de la fin de vie, sont des facteurs de risque majeurs de détresse spirituelle. Cette souffrance peut avoir des conséquences considérables sur la qualité de vie, la santé physique, psychique et sociale du patient, qui expérimente une perte de sens, de motivation, et d’identité. Sa qualité de vie ainsi que celle de ses proches se trouve gravement altérée, au point que le patient peut être tenté par la désespérance. 7 études publiées entre 2006 et 2014 et sélectionnées dans les principales bases de données scientifiques en soins infirmiers ont été analysées. Les principales compétences requises pour accompagner la détresse spirituelle sont la conscience de sa propre spiritualité, l’accueil de sa vulnérabilité en tant que guérisseur blessé, l’ouverture à la dynamique relationnelle, la révélation des ressources du patient, et l’aptitude à dépister et évaluer la détresse spirituelle. Des recommandations institutionnelles et organisationnelles ont été émises afin de favoriser le développement de ces compétences infirmières et de prévenir ou soulager la détresse spirituelle des patients

Transcriptome analysis of Listeria monocytogenes exposed to biocide stress reveals a multi-system response involving cell wall synthesis, sugar uptake, and motility

peer-reviewedListeria monocytogenes is a virulent food-borne pathogen most often associated with the consumption of “ready-to-eat” foods. The organism is a common contaminant of food processing plants where it may persist for extended periods of time. A commonly used approach for the control of Listeria monocytogenes in the processing environment is the application of biocides such as quaternary ammonium compounds. In this study, the transcriptomic response of a persistent strain of L. monocytogenes (strain 6179) on exposure to a sub-lethal concentration of the quaternary ammonium compound benzethonium chloride (BZT) was assessed. Using RNA-Seq, gene expression levels were quantified by sequencing the transcriptome of L. monocytogenes 6179 in the presence (4 ppm) and absence of BZT, and mapping each data set to the sequenced genome of strain 6179. Hundreds of differentially expressed genes were identified, and subsequent analysis suggested that many biological processes such as peptidoglycan biosynthesis, bacterial chemotaxis and motility, and carbohydrate uptake, were involved in the response of L. monocyotogenes to the presence of BZT. The information generated in this study further contributes to our understanding of the response of bacteria to environmental stress. In addition, this study demonstrates the importance of using the bacterium's own genome as a reference when analysing RNA-Seq data.This work was supported by the E.U.7th framework projects PROMISE (project number 265877)and FOODSEG(project number 266061).Aidan Casey was supported by the Teagasc Walsh Fellowship programme

Observation of Highly Nonlinear Resistive Switching of Al2O3/TiO2-x Memristors at Cryogenic Temperature (1.5 K)

In this work, we investigate the behavior of Al2O3/TiO2-x cross-point memristors in cryogenic environment. We report successful resistive switching of memristor devices from 300 K down to 1.5 K. The I-V curves exhibit negative differential resistance effects between 130 and 1.5 K, attributed to a metal-insulator transition (MIT) of the Ti4O7 conductive filament. The resulting highly nonlinear behavior is associated to a maximum ION/IOFF ratio of 84 at 1.5 K, paving the way to selector-free cryogenic passive crossbars. Finally, temperature-dependant thermal activation energies related to the conductance at low bias (20 mV) are extracted for memristors in low resistance state, suggesting hopping-type conduction mechanisms.Comment: 4 pages, 4 figures, IEEE 14th Nanotechnology Materials & Devices Conference (NMDC 2019

A tail of two phages: genomic and functional analysis of Listeria monocytogenes phages vB_LmoS_188 and vB_LmoS_293 reveal the receptor-binding proteins involved in host specificity

The physical characteristics of bacteriophages establish them as viable candidates for downstream development of pathogen detection assays and biocontrol measures. To utilize phages for such purposes, a detailed knowledge of their host interaction mechanisms is a prerequisite. There is currently a wealth of knowledge available concerning Gram-negative phage-host interaction, but little by comparison for Gram-positive phages and Listeria phages in particular. In this research, the lytic spectrum of two recently isolated Listeria monocytogenes phages (vB_LmoS_188 and vB_LmoS_293) was determined, and the genomic basis for their observed serotype 4b/4e host-specificity was investigated using comparative genomics. The late tail genes of these phages were identified to be highly conserved when compared to other serovar 4-specific Listeria phages. Spontaneous mutants of each of these phages with broadened host specificities were generated. Their late tail gene sequences were compared with their wild-type counterparts resulting in the putative identification of the products of ORF 19 of vB_LmoS_188 and ORF 20 of vB_LmoS_293 as the receptor binding proteins of these phages. The research findings also indicate that conserved baseplate architectures and host interaction mechanisms exist for Listeria siphoviruses with differing host-specificities, and further contribute to the current knowledge of phage-host interactions with regard to Listeria phages

Conductive filament evolution dynamics revealed by cryogenic (1.5 K) multilevel switching of CMOS-compatible Al2O3/TiO2 resistive memories

This study demonstrates multilevel switching at 1.5 K of Al2O3/TiO2-x resistive memory devices fabricated with CMOS-compatible processes and materials. The I-V characteristics exhibit a negative differential resistance (NDR) effect due to a Joule-heating-induced metal-insulator transition of the Ti4O7 conductive filament. Carrier transport analysis of all multilevel switching I-V curves show that while the insulating regime follows the space charge limited current (SCLC) model for all resistance states, the conduction in the metallic regime is dominated by SCLC and trap-assisted tunneling (TAT) for low- and high-resistance states respectively. A non-monotonic conductance evolution is observed in the insulating regime, as opposed to the continuous and gradual conductance increase and decrease obtained in the metallic regime during the multilevel SET and RESET operations. Cryogenic transport analysis coupled to an analytical model accounting for the metal-insulator-transition-induced NDR effects and the resistance states of the device provide new insights on the conductive filament evolution dynamics and resistive switching mechanisms. Our findings suggest that the non-monotonic conductance evolution in the insulating regime is due to the combined effects of longitudinal and radial variations of the Ti4O7 conductive filament during the switching. This behavior results from the interplay between temperature- and field-dependent geometrical and physical characteristics of the filament.Comment: 8 pages, 4 figure

Technology platform for the fabrication of titanium nanostructures

Abstract : This paper presents two approaches for the fabrication of top-down titanium nanostructures. The first approach involves electron beam lithography followed by a tailored titanium plasma etching. The two main challenges of this process lie in the optimization of the negative tone Ma–N electroresist resolution and in the definition of a controlled titanium etching process for titanium patterns less than 20 nm thick and wide. The second proposed approach is a damascene process where the titanium nanostructures are buried in the oxide. Very shallow and narrow (20 nm × 20 nm) trenches are first patterned in the oxide and nanostructures are obtained by planarization of an evaporated titanium film. The dimensions of the structures are defined by the electron beam lithography resolution and the etching recipe. The third dimension is given by the titanium or any other metal thickness and can be controlled down to few nanometers thanks to the planarization step

Selective dry etching of TiN nanostructures over SiO2 nanotrenches using a CI2/Ar/N2 inductively coupled plasma

Abstract : An inductively coupled plasma etch process for the fabrication of TiN nanostructures over nanotopography is presented. Using a Cl2/Ar/N2 plasma, a selectivity of 50 is achieved over SiO2. The effect of N2 flow rate on the etch rates and the nonvolatile residues on TiN sidewalls is investigated. As N2 flow rate is increased up to 50 sccm, a change in the deposition of the nonvolatile residues on TiN sidewalls is observed. The current density–voltage characterizations of TiN devices fabricated with TiN nanostructure sidewalls are presented. The measured current densities of two different samples etched with low and high N2 flow rate, respectively, demonstrated the presence after cleaning of an insulating layer deposited on the sidewalls for low N2 flow rate only