Anisotropy-based mechanism for zigzag striped patterns in magnetic thin films

In this work we studied a two dimensional ferromagnetic system using Monte Carlo simulations. Our model includes exchange and dipolar interactions, a cubic anisotropy term, and uniaxial out-of-plane and in-plane ones. According to the set of parameters chosen, the model including uniaxial out-of-plane anisotropy has a ground-state which consists of a canted state with stripes of opposite out-of-plane magnetization. When the cubic anisotropy is introduced zigzag patterns appear in the stripes at fields close to the remanence. An analysis of the anisotropy terms of the model shows that this configuration is related to specific values of the ratio between the cubic and the effective uniaxial anisotropy. The mechanism behind this effect is related to particular features of the anisotropy's energy landscape, since a global minima transition as a function of the applied field is required in the anisotropy terms. This new mechanism for zigzags formation could be present in monocrystal ferromagnetic thin films in a given range of thicknesses.Comment: 910 pages, 10 figure

Late Winter Dietary Overlap among Greater Rheas and Domestic Herbivores on the Argentinean Flooding Pampa

This study evaluates the dietary overlap among greater rheas (Rhea americana L.) sheep and cattle in the Flooding Pampa, Buenos Aires, Argentina during late winter, when is observed the lowest forage availability. The work was carried out with the following forage classes (FC): warm and cool season grasses and forbs (legumes and no-legumes). Diet botanical composition was estimated by microanalysis of faeces. Principal Component Analysis and Kulcyznsky´s index of similarity were used for data analysis. Rhea populations selected diets with higher forb percentages. On the contrary, vegetation structure and their own morpho-physiology conditioned cattle to diets almost exclusively gramineous. Although forbs were more consumed by sheep than by cattle, they do not represent a major portion of sheep diets. In the Flooding Pampa grasslands, the probability of competition for forage between greater rheas and sheep is intermediate, and that between rheas and cattle is low

Magnetic field dependence of antiferromagnetic resonance in NiO

We report on measurements of magnetic field and temperature dependence of antiferromagnetic resonances in the prototypical antiferromagnet NiO. The frequencies of the magnetic resonances in the vicinity of 1 THz have been determined in the time-domain via time-resolved Faraday measurements after selective excitation by narrow-band superradiant terahertz (THz) pulses at temperatures down to 3 K and in magnetic fields up to 10 T. The measurements reveal two antiferromagnetic resonance modes, which can be distinguished by their characteristic magnetic field dependencies. The nature of the two modes is discussed by comparison to an eight-sublattice antiferromagnetic model, which includes superexchange between the next-nearest-neighbor Ni spins, magnetic dipolar interactions, cubic magneto-crystalline anisotropy, and Zeeman interaction with the external magnetic field. Our study indicates that a two-sublattice model is insufficient for the description of spin dynamics in NiO, while the magnetic-dipolar interactions and magneto-crystalline anisotropy play important roles

Correlation between magnetic interactions and domain structure in A1 FePt ferromagnetic thin films

We have investigated the relationship between the domain structure and the magnetic interactions in a series of FePt ferromagnetic thin films of varying thickness. As-made films grow in the magnetically soft and chemically disordered A1 phase that may have two distinct domain structures. Above a critical thickness $d_{cr}\sim 30$ nm the presence of an out of plane anisotropy induces the formation of stripes, while for $d<d_{cr}$ planar domains occur. Magnetic interactions have been characterized using the well known DCD-IRM remanence protocols, $\delta M$ plots, and magnetic viscosity measurements. We have observed a strong correlation between the domain configuration and the sign of the magnetic interactions. Planar domains are associated with positive exchange-like interactions, while stripe domains have a strong negative dipolar-like contribution. In this last case we have found a close correlation between the interaction parameter and the surface dipolar energy of the stripe domain structure. Using time dependent magnetic viscosity measurements, we have also estimated an average activation volume for magnetic reversal, $\langle V_{ac}\rangle \sim 1.37\times 10^{4}$ nm$^{3},$ which is approximately independent of the film thickness or the stripe period.Comment: 25 pages, 11 figure

Assessment of the main stone fruit viruses and viroids in Algeria

In order to improve the sanitary status of the propagating material of stone fruits, a field survey was conducted to assess the main viruses and viroids affecting stone fruits in selected growing areas and their distribution on the collected material by using serological and molecular detection methods.Serological assays were carried out to detect Plum pox virus (PPV), Prunus necrotic ring spot virus (PNRSV), Prune dwarf virus (PDV), Apple mosaic virus (ApMV) and Apple chlorotic leaf spot virus (ACLSV). Moreover, tissue-print hybridization was performed to detect Peach latent mosaic viroid (PLMVd) and Hop stunt viroid (HSVd).Among nearly 2000 trees tested, no PPV infection was detected, while 14% of them positively reacted to at least one virus. The highest infection rate (18%) was reported in both nurseries and commercial orchards. PNRSV was the most detected virus (9%), followed by ApMV (3%) and PDV (1.5%). Cherry was the most infected species (20%). As for viroids, a high infection rate was recorded for PLMVd (9%) and HSVd (5%); the highest infection rate was reported in mother blocks and varietal collections.Keywords: Algeria, Prunus, virus, viroids, ELISA, tissue-print hybridization, sanitary statu

Temporal and spatial variability of prehistoric aquatic resource procurement: a case study from Mesolithic Northern Iberia

Prehistoric shell middens hold valuable evidence of past human–environment interactions. In this study, we used carbon (δ13C) and oxygen (δ18O) stable isotopes of Mytilus galloprovincialis shells excavated from El Perro, La Fragua and La Chora, three Mesolithic middens in Cantabria, Northern Spain, to examine hunter-gatherer subsistence strategies in terms of seasonality and collection areas. Furthermore, we used shell δ18O to reconstruct water temperature during the early Holocene. Stable isotopes reveal a shellfish harvesting diversification trend represented by the gradual establishment of the upper estuaries as new procurement areas and an increase of harvesting mobility in both coastal and in-land sites. These innovations in subsistence strategies during the Mesolithic coincided with major changes in the surrounding environment as attested by the water temperature reconstructions based on δ18O and backed by several global and regional records. Overall, our results show that shell δ13C and δ18O stable isotopes have an underexplored potential as provenance proxies which stimulates their application to the archaeological record to further understand prehistoric human resource procurement and diet

Relativistic orbits and Gravitational Waves from gravitomagnetic corrections

Corrections to the relativistic theory of orbits are discussed considering higher order approximations induced by gravitomagnetic effects. Beside the standard periastron effect of General Relativity (GR), a new nutation effect was found due to the ${\displaystyle c^{-3}}$ orbital correction. According to the presence of that new nutation effect we studied the gravitational waveforms emitted through the capture in a gravitational field of a massive black hole (MBH) of a compact object (neutron star (NS) or BH) via the quadrupole approximation. We made a numerical study to obtain the emitted gravitational wave (GW) amplitudes. We conclude that the effects we studied could be of interest for the future space laser interferometric GW antenna LISA.Comment: 6 pages, 10 figures; Multifrequency Behaviour of High-Energy Cosmic Sources, Vulcano Workshop 200

Can Polarity-Inverted Surfactants Self-Assemble in Nonpolar Solvents

We investigate the self-assembly process of a surfactant with inverted polarity in water and cyclohexane using both all-atom and coarse grained hybrid particle-field molecular dynamics simulations. Unlike conventional surfactants, the molecule under study, proposed in a recent experiment, is formed by a rigid and compact hydrophobic adamantane moiety, and a long and floppy triethylene glycol tail. In water, we report the formation of stable inverted micelles with the adamantane heads grouping together into a hydrophobic core, and the tails forming hydrogen bonds with water. By contrast, microsecond simulations do not provide evidence of stable micelle formation in cyclohexane. Validating the computational results by comparison with experimental diffusion constant and small-angle X-ray scattering intensity, we show that at laboratory thermodynamic conditions the mixture resides in the supercritical region of the phase diagram, where aggregated and free surfactant states co-exist in solution. Our simulations also provide indications about how to escape this region, to produce thermodynamically stable micellar aggregates.Comment: 14 pages, 10 Figures, accepted for publication (2020

ANALISIS PENGEMBANGAN KAWASAN PERMUKIMAN BERDASARKAN KEMAMPUAN LAHAN DI DISTRIK MUARA TAMI

Kota sering diartikan sebagai suatu permukaan wilayah dimana terdapat pemusatan penduduk dengan berbagai jenis kegiatan ekonomi, sosial, budaya dan administrasi pemerintah yang secara rinci dapat digambarkan meliputi lahan geografis utamanya untuk pemukiman, dalam jumlah penduduk yang relatif  besar dan lahan yang  relatif terbatas. Sehubungan dengan hal tersebut, nampak adanya keterkaitan yang nyata antara manusia dengan lingkungan (lahan), yang digunakan manusia untuk tempat tinggal, dan tempat beraktivitas. Perkembangan kota umumnya memanfaatkan lahan untuk dijadikan pemukiman, hal ini tidak lain dikarenakan semakin meningkatnya laju pertumbuhan penduduk yang ada di kota atau wilayah tersebut, sehingga permintaan akan lahan baru untuk pemukiman semakin banyak dan meningkat. Untuk itulah sebelum adanya pengembangan kota baru dilakukan analisis kemampuan lahan di Distrik Muara Tami menggunakan system information Geographic ( SIG ). Distrik Muara Tami mempunyai 5 klasifikasi yaitu sedang, sangat rendah, rendah, agak tinggi, dan sangat tinggi. Kemampuan pengembangan sedang yang lebih mendominasi di Distrik Muara tami. Secara umum cukup layak untuk dijadikan sebagai pengembangan kota baru. Sedangkan untuk Kemampuan Lahan yang tidak mendominasi di Distrik Muara Tami adalah Kemampuan Pengembangan Sangat Tinggi hal ini menunjukan hanya sebagian kecil wilayah Muara Tami yang mampu untuk dikembangkan, khususnya  sebagai wilayah pengembangan kota baru.Kata Kunci: Kota, Permukiman, Distrik Muara Tami, Kemampuan Lahan

Knotless PEEK and double-loaded biodegradable suture anchors ensure comparable clinical outcomes in the arthroscopic treatment of traumatic anterior shoulder instability: a prospective randomized study

Purpose: To compare the clinical outcome of arthroscopic capsulolabral repair for traumatic anterior shoulder instability with PEEK knotless and knotted biodegradable suture anchors. Methods: Arthroscopic stabilization was performed in 78 patients with recurrent traumatic anterior shoulder instability. They were divided into 2 groups of 39 patients each, according to suture anchors used: knotless PEEK anchors in group 1, and biodegradable anchors in group 2. Exclusion criteria were: instability without dislocation, posterior or multidirectional instability, glenoid bone loss > 20%, off-track lesions, concomitant rotator cuff tears and previous surgery. The primary outcome was the Disabilities of the Arm, Shoulder and Hand (DASH) self-administered questionnaire. Secondary outcomes were: Work-DASH, Sport-DASH, Rowe score, recurrent instability and subsequent surgery. The following independent variables were considered: age, gender, dominance, generalized ligamentous hyperlaxity, duration of symptoms, age at first dislocation, number of dislocations, type of work, type of sport, sports activity level, capsule-labral injury pattern, SLAP lesion and number of anchors. Differences between groups for numerical variables were analyzed by use of the Student’s t-test or Mann–Whitney U-test. Fisher’s exact test was used for analysis of categorical variables. Significance was set at p < 0.05. Results: Seven patients (9%) were lost at follow-up, 5 from group 1 and 2 from group 2. Follow-up ranged from 36 to 60 months (median: 44; IQR: 13). Comparison between groups did not show significant differences for each independent variable considered. No differences could be found either for DASH (n.s.) or Rowe (p = n.s.) scores between the two groups. Overall recurrence rate was 7%. Three re-dislocations were reported in group 1 and two in group 2 (n.s.). Only one patient in each group underwent re-operation. Conclusions: The study showed no significant differences in clinical outcomes after arthroscopic treatment of traumatic anterior shoulder instability using PEEK knotless or biodegradable knotted anchors at mid-term follow-up. Level of evidence: I