Whether rare-earth materials can be used as single-atom magnetic memory is an ongoing debate in recent literature. Here we show, by inelastic and spin-resolved scanning tunnelling-based methods, that ...we observe a strong magnetic signal and excitation from Fe atoms adsorbed on Pt(111), but see no signatures of magnetic excitation or spin-based telegraph noise for Ho atoms. Moreover, we observe that the indirect exchange field produced by a single Ho atom is negligible, as sensed by nearby Fe atoms. We demonstrate, using ab initio methods, that this stems from a comparatively weak coupling of the Ho 4f electrons with both tunnelling electrons and substrate-derived itinerant electrons, making both magnetic coupling and detection very difficult when compared to 3d elements. We discuss these results in the context of ongoing disputes and clarify important controversies.
Magnetoelectric coupling is studied using the electric field between the tip of a spin-polarized scanning tunneling microscope and a nanomagnet. Our experiments show that a negative (positive) ...electric field stabilizes (destabilizes) in-plane magnetization against thermal agitation, whereas it destabilizes (stabilizes) out-of-plane magnetization. We conclude that the electric field E induces a uniaxial anisotropy that favors in-plane magnetization for E<0 and out-of-plane magnetization for E>0. Our experiments demonstrate magnetic manipulation on the atomic scale without exploiting spin or charge currents.
A cluster of a few magnetic atoms on the surface of a nonmagnetic substrate is one suitable realization of a bit for spin-based information technology. The prevalent approach to achieve magnetic ...stability is decoupling the cluster spin from substrate conduction electrons in order to suppress destabilizing spin-flips. However, this route entails less flexibility in tailoring the coupling between the bits needed for spin-processing. Here, we use a spin-resolved scanning tunneling microscope to write, read, and store spin information for hours in clusters of three atoms strongly coupled to a substrate featuring a cloud of non-collinearly polarized host atoms, a so-called non-collinear giant moment cluster. The giant moment cluster can be driven into a Kondo screened state by simply moving one of its atoms to a different site. Using the exceptional atomic tunability of the non-collinear substrate mediated Dzyaloshinskii-Moriya interaction, we propose a logical scheme for a four-state memory.Information technology based on few atom magnets requires both long spin-energy relaxation times and flexible inter-bit coupling. Here, the authors show routes to manipulate information in three-atom clusters strongly coupled to substrate electrons by exploiting Dzyaloshinskii-Moriya interactions.
A correct description of fine (diameter <1 μm) and ultrafine (<0.1 μm) aerosol particles in urban areas is of interest for particle exposure assessment but also basic atmospheric research. We ...examined the spatio-temporal variability of atmospheric aerosol particles (size range 3–800 nm) using concurrent number size distribution measurements at a maximum of eight observation sites in and around Leipzig, a city in Central Europe. Two main experiments were conducted with different time span and number of observation sites (2 years at 3 sites; 1 month at 8 sites). A general observation was that the particle number size distribution varied in time and space in a complex fashion as a result of interaction between local and far-range sources, and the meteorological conditions. To identify statistically independent factors in the urban aerosol, different runs of principal component (PC) analysis were conducted encompassing aerosol, gas phase, and meteorological parameters from the multiple sites. Several of the resulting PCs, outstanding with respect to their temporal persistence and spatial coverage, could be associated with aerosol particle modes: a first accumulation mode ("droplet mode", 300–800 nm), considered to be the result of liquid phase processes and far-range transport; a second accumulation mode (centered around diameters 90–250 nm), considered to result from primary emissions as well as aging through condensation and coagulation; an Aitken mode (30–200 nm) linked to urban traffic emissions in addition to an urban and a rural Aitken mode; a nucleation mode (5–20 nm) linked to urban traffic emissions; nucleation modes (3–20 nm) linked to photochemically induced particle formation; an aged nucleation mode (10–50 nm). Additional PCs represented only local sources at a single site, or infrequent phenomena. In summary, the analysis of size distributions of high time and size resolution yielded a surprising wealth of statistical aerosol components occurring in the urban atmosphere over one single city. A paradigm on the behaviour of sub-μm urban aerosol particles is proposed, with recommendations how to efficiently monitor individual sub-fractions across an entire city.
The influence of a high spin-polarized tunnel current onto the switching behavior of a superparamagnetic nanoisland on a nonmagnetic substrate is investigated by means of spin-polarized scanning ...tunneling microscopy. A detailed lifetime analysis allows for a quantification of the effective temperature rise of the nanoisland and the modification of the activation energy barrier for magnetization reversal, thereby using the nanoisland as a local thermometer and spin-transfer torque analyzer. Both the Joule heating and spin-transfer torque are found to scale linearly with the tunnel current. The results are compared to experiments performed on lithographically fabricated magneto-tunnel junctions, revealing a very high spin-transfer torque switching efficiency in our experiments.
Background
Hand eczema (HE) is a common skin disease with major medical psychological and socio‐economic implications. Onset and prognosis of HE are determined by individual as well as environmental ...factors. So far, most epidemiological data on HE have been reported from Scandinavian and recently German studies.
Objective
To investigate the characteristics and medical care of patients with chronic HE (CHE) in Switzerland, and identify risk factors.
Methods
In this cross‐sectional study, data from patients with chronic HE were obtained by means of medical history, dermatological examination and patient questionnaires. Multiple logistic regression analysis was applied to identify risk factors for high severity and dermatology life quality index (DLQI).
Results
In seven dermatology departments, 199 patients (mean age 40.4 years, 50.8% female) with CHE (mean duration 6.6 years) were enrolled. Moderate to severe HE was reported by 70.9% of patients, and was associated with age <30 or >50 years, localization of lesions and pruritus. Because of the CHE, 37.3% of patients were on sick leave over the past 12 months, 14.8% had changed or lost their job. Practically all patients applied topical therapy, 21% were treated with alitretinoin, and 21% with psoralen plus UVA light (PUVA). The effects on the health‐related quality of life was moderate to large in 33.7% and 39.4% of CHE patients, respectively. Factors associated with a high impact on DLQI (mean 9.7 ± 5.8) were female sex, lesions on back of the hands and pruritus as well as mechanical skin irritation and wearing gloves.
Conclusion
In agreement with recent studies, the Swiss data demonstrate the high impact of CHE on medical well‐being, patient quality of life and work ability. As it is associated with an intense use of health care services, high rate of sick leave, job loss and change, CHE may cause a high socio‐economic burden.
The rates of a hindered molecular rotation induced by tunneling electrons are evaluated using scattering theory within the sudden approximation. Our approach explains the excitation of copper ...phthalocyanine molecules (CuPc) on Cu(111) as revealed in a recent measurement of telegraph noise in a scanning tunneling microscopy experiment Schaffert et al., Nat. Mater. 12, 223 (2013) (http://dx.doi.org/10.1038/nmat3527). A complete explanation of the experimental data is performed by computing the geometry of the adsorbed system, its electronic structure, and the energy transfer between tunneling electrons and the molecule's rotational degree of freedom. The results unambiguously show that tunneling electrons induce a frustrated rotation of the molecule. In addition, the theory determines the spatial distribution of the frustrated rotation excitation, confirming the striking dominance of two out of four molecular lobes in the observed excitation process. This lobe selectivity is attributed to the different hybridizations with the underlying substrate.
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► PTCDA and CuPc are consecutively evaporated onto a Cu(111) substrate. ► Molecular phases after an annealing step are studied by LT-STM and LEED. ► Molecular phases include a highly ...ordered (HO) and a disordered mixed molecular phase.► HO phase seems to be thermodynamically favored. ► HO mixed molecular phase can be tailored from prepatterned dense PTCDA domains.
We report on the molecular self-assembly of a highly ordered mixed molecular structure of copper–phthalocyanine (CuPc) and 3,4,9,10–perylene–tetracarboxylic–dianhydride (PTCDA) on Cu(111) starting from dense PTCDA domains. Low temperature scanning tunneling microscopy (LT-STM) data reveal the surface structure as the CuPc coverage is stepwise increased. A highly ordered mixed phase as well as a disordered mixed phase can be found, where the highly ordered mixed phase seems to be thermodynamically favored. Low energy electron diffraction (LEED) measurements aid the STM analysis. Tentative models for the formation of the highly ordered mixed phase are given.
Abstract
The objectives of study were to evaluate effects of various anthelmintic treatments on fecal egg counts (FEC), ADG, fly counts, and blood parameters in newly received stocker calves. Upon ...arrival to the Murray State University Beef Unit, steers (n = 30) were allow a 1 wk adjustment period prior to allocation of treatment. Steers were randomly allocated to treatment based on BW (297.77 ± 16.53 kg) and FEC (43.10 eggs/gram; EPG). Treatments included: control (n = 10; no anthelmintic treatment; CON); moxidectin/oxfendazole combination (n = 10; COMBO); and a long-acting eprinomectin (n = 10; LAE). Steers were comingled and allowed to grazed mixed grass pastures with rotation occurring based on forage availability. Body weight, fecal and blood samples were collected on d 0, 27, 56, and 101 and the following blood parameters evaluated: white blood cell count (WBC), platelets (PLA), neutrophils (NEU), lymphocytes (LYM), monocytes (MON), basophils (BASO), and eosinophils (EOS). Fly counts were estimated on d 0, 31, 61, and 100. Data was analyzed using the PROC MIXED procedure of SAS with steer as the experimental unit and d as a repeated measure. Two preplanned orthogonal contrasts were used to determine effects and included comparisons between: 1) CON vs. treated steers, and 2) COMBO vs. LEA steers. Strongyle EPG were similar between CON and treated steers (P > 0.1) but EPG were higher (P = 0.02) for COMBO vs. LAE steers (22.97 vs. 5.61 EPG, respectively). A treatment × d interaction was found for EPG (P = 0.02). Body weight and ADG was similar (P > 0.1) between treatments; however, ADG from d 27 to 56 was greater (P = 0.04) for LAE vs. COMBO steers (1.29 vs. 0.54). An effect of d (P < 0.01) was observed for fly counts and the following blood parameters: WBC, NEU, LYM, MON, BASO, and EOS. Esonophils were greater (P = 0.03) in LAE vs. COMBO steers (0.32 vs. 0.19, respectively) while MON tended to be greater (P = 0.06) for LAE and COMBO steers (0.82 vs. 0.65, respectively). Data suggests that anthelmintic use may have affected FEC, ADG, and blood parameters in newly received stocker calves.
Abstract
The objectives of this study were to evaluate effects of various anthelmintic treatments on fecal egg counts (FEC) and performance of newly received stocker calves. Upon arrival to the ...Murray State University Beef Unit, steers (n = 66) were allowed a 7 d adjustment period prior to allocation of treatment. Steers were randomly allocated to treatment based on BW (296.41 ± 23.67 kg) and FEC (13.67 eggs/gram; EPG). Treatments included: control (n = 10; no anthelmintic administration; CON); moxidectin/oxfendazole combination (n = 28; COMBO); and long-acting eprinomectin (n = 28; LAE). Steers were comingled and grazed mixed grass pastures with rotation based on forage availability. Paddock size ranged from 0.40 to 0.81-ha with an average stocking density of 47,255.4 kg/ha. Fecal samples, BW, BCS, and hair coat scores (HCS) were collected on d 0, 13, 27, 56, 90, and 101. Fly counts were performed from an all-terrain vehicle while steers grazed on d 14, 31, 61, 91, and 100. Statistical analysis was performed using the MIXED procedure of SAS (experimental unit = steer, repeated measure = day). Two preplanned orthogonal contrasts were used to evaluate effects and included comparisons of: 1) CON vs treated steers; and 2) COMBO vs LAE steers. Controls differed from treated steers for EPG (P = 0.05) and LAE steers differed from COMBO steers (P < 0.01). A treatment × d interaction (P < 0.01) was detected for EPG. The highest EPG were observed in the COMBO steers on d 101, 90, 56 (62.57, 47.34, and 44.73 EPG, respectively) with the fewest EPG observed on d 13 (COMBO = 1.56, LAE = 2.02 EPG). Body weight and ADG were similar between treatments throughout the study (P > 0.09) except for ADG from d 13 to 27, in which CON steers exhibited a higher ADG (P = 0.04) compared to treated steers (1.03 vs 0.24). Greater (P = 0.06) BCS were observed for CON versus treated steers on d 27 (5.5 vs 5, respectively); however, BCS were similar (P > 0.1) throughout the rest of the study. Fly counts were not affected (P = 0.78) by treatment, but were affected (P < 0.01) by d with the highest fly counts occurring on d 100 and the fewest flies on d 31 (19.49 and 6.14, respectively). Data suggest anthelmintic use may reduce FEC without improving performance in stocker calves under management intensive grazing systems.
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