Study of the charge correlation function in one-dimensional Hubbard heterostructures

We study inhomogeneous one-dimensional Hubbard systems using the density matrix renormalization group method. Different heterostructures are investigated whose configuration is modeled varying parameters like the on-site Coulomb potential and introducing local confining potentials. We investigate their Luttinger liquid properties through the parameter K_rho, which characterizes the decay of the density-density correlation function at large distances. Our main goal is the investigation of possible realization of engineered materials and the ability to manipulate physical properties by choosing an appropriate spatial and/or chemical modulation.Comment: 6 pages, 7 figure

Diode area melting single-layer parametric analysis of 316L stainless steel powder

Diode area melting (DAM) is a novel additive manufacturing process that utilises customised architectural arrays of low power laser diode emitters for high speed parallel processing of metallic powdered feedstock. The laser diodes operate at shorter laser wavelengths (808 nm) than conventional SLM fibre lasers (1064 nm) theoretically enabling more efficient energy absorption for specific materials. This investigation presents a parametric analysis of the DAM process, identifying the effect of powder characteristics, laser beam profile, laser power and scan speed on the porosity of a single-layer sample. Also presented is the effect of process energy density on melt pool depth (irradiated thermal energy penetration capable of achieving melting) on 316L stainless steel powder. An analysis of the density and the melt depth fraction of single layers is presented in order to identify the conditions that lead to the fabrication of fully dense DAM parts. Energy densities in excess of 86 J/mm3 were theorised as sufficient to enable processing of fully dense layers

Bioenergy transition as a strategic mechanism to diversify energy sources in rural areas in Colombia

Received: February 1st, 2023 ; Accepted: May 27th, 2023 ; Published: October 14th, 2023 ; Correspondence: [email protected], [email protected] growth in population has resulted in an increase in the consumption of goods and services, which has led to a surge in waste generation and the use of fossil fuels. To mitigate the envi-ronmental issues associated with improper waste management and reduce greenhouse gas emissions from fossil fuels, residual organic matter can be used to produce bioenergy in the form of biogas and biomethane through anaerobic digestion (AD). These biofuels can act as substitutes for liquefied petroleum gas (LPG) and natural gas (NG) and can be utilized for power and heat generation. In Colombia, the current production of biogas is 4 MW, and the government aims to increase its utilization by promoting the inclusion of biogas and biomethane in the energy matrix through a supportive regulatory framework. Studies suggest that the theoretical energy potential of livestock waste in Colombia is estimated to be 2,673 MW, but the current technological conditions allow for the utilization of only 198 MW, with the pork sector contributing 34%. This study examines the legal context and the present state of biogas in the Colombian energy matrix, while exploring the potential of the Colombian pig farming sector for biogas production. The social, economic, and environmental barriers and opportunities faced by this sector in becoming an energy producer during the transition period are also identified. The findings suggest that biogas presents a sustainable energy solution for rural areas of Colombia where pig farming is a prominent economic activity. Biogas can replace traditional fuels like LPG and firewood for cooking purposes or serve as a complementary source for electricity and thermal energy production in non-interconnected zones. This could mitigate environmental issues and reduce the prevalence of respiratory diseases associated with the use of firewood

Element-Specific Depth Profile of Magnetism and Stoichiometry at the La0.67Sr0.33MnO3/BiFeO3 Interface

Depth-sensitive magnetic, structural and chemical characterization is important in the understanding and optimization of novel physical phenomena emerging at interfaces of transition metal oxide heterostructures. In a simultaneous approach we have used polarized neutron and resonant X-ray reflectometry to determine the magnetic profile across atomically sharp interfaces of ferromagnetic La0.67Sr0.33MnO3 / multiferroic BiFeO3 bi-layers with sub-nanometer resolution. In particular, the X-ray resonant magnetic reflectivity measurements at the Fe and Mn resonance edges allowed us to determine the element specific depth profile of the ferromagnetic moments in both the La0.67Sr0.33MnO3 and BiFeO3 layers. Our measurements indicate a magnetically diluted interface layer within the La0.67Sr0.33MnO3 layer, in contrast to previous observations on inversely deposited layers. Additional resonant X-ray reflection measurements indicate a region of an altered Mn- and O-content at the interface, with a thickness matching that of the magnetic diluted layer, as origin of the reduction of the magnetic moment.Comment: 13 pages, 4 figures, supplemental material include

Differences in Frontal Plane Knee Kinematics by Grip, Load, and Concentric Subphase in the Front Squat

Although the back squat is one of few exercises that has been extensively analyzed, the body of literature examining its counterpart, the front squat, is not as robust. The front squat is a vital exercise known for its quadricep development capabilities and unique front-rack positioning. This grip position renders the front squat more difficult, and thus proper form is more vital to prevent injury. PURPOSE: To evaluate the association between grip (standard front-rack, cross-grip, and strap-assisted), load (50% and 80% of 1-RM), and subphases of the concentric portion of the squat on frontal plane knee varus and valgus movement in the front squat. METHODS: Data was gathered from eight participants. Inclusion criteria were at least 60% on the Lower Extremity Functional Scale, self-report of performing front squats at least every two weeks for the past six months, and squatting below parallel. Two sessions were completed. First, consent, anthropometrics, and a 1-RM were obtained. Next, each subject was randomized to perform four repetitions of each grip at 50% and 80% of their 1-RM. During this session, a 29-marker set for 3D motion capture was used to collect joint angle data for each squat. We used data from knee frontal plane angles to analyze the concentric portion of the squat which we broke into subphases (1: 25%, 2: 50%, 3: 75% and 4: 100%) by frame. Only the second repetition from the left leg was analyzed. We performed a three-way repeated measures ANOVA for within-subject factors of grip technique (front-rack, cross-grip, strap-assisted), load (50%, 80%), and sub-phase of the concentric part of the squat (1, 2, 3, 4). We performed a sensitivity analysis with data from the second repetition of the right leg. Analyses were performed using R, version 4.0.3. Significance was set at p\u3c0.05. RESULTS: The eight participants (6 males, 2 females) were 173.10 ± 8.00cm (mean ± sd) in height, 78.20 ± 12.30kg in mass, 25 ± 3yrs of age, reported 6 ± 4 yrs of training experience, and had a 1-RM of 114.10 ± 31.00kg. There were no significant main effects for grip or load on knee varus/valgus movement in the frontal plane. However, there was a significant main effect for subphases of the concentric portion of the squat (p\u3c0.001). Except for between phases 3 and 4, there were significant differences between all pairwise comparisons of phases (p\u3c0.001 for all remaining except between 2 and 3, p = 0.002); whereas varus movement was found in phase 1, valgus movement was found in phase 2. Sensitivity analyses on the right leg yielded similar results. CONCLUSION: Our findings suggest that the subphases of the concentric portion of the front squat, but not grip or load, were significantly associated with varus/valgus movement of the knee. Therefore, strength coaches can choose a grip and load that is most appropriate for the specific athlete without significant impact on varus/valgus movement. However, regardless of grip or load, strength coaches should tune in closely to the concentric subphases of the front squat. In particular, to better prevent injury, strength coaches should focus on the first and second subphases phases where significant frontal plane movement may occur

PTH(1–34) treatment and/or mechanical loading have different osteogenic effects on the trabecular and cortical bone in the ovariectomized C57BL/6 mouse

In preclinical mouse models, a synergistic anabolic response to PTH(1–34) and tibia loading was shown. Whether combined treatment improves bone properties with oestrogen deficiency, a cardinal feature of osteoporosis, remains unknown. This study quantified the individual and combined longitudinal effects of PTH(1–34) and loading on the bone morphometric and densitometric properties in ovariectomised mice. C57BL/6 mice were ovariectomised at 14-weeks-old and treated either with injections of PTH(1–34); compressive loading of the right tibia; both interventions concurrently; or both interventions on alternating weeks. Right tibiae were microCT-scanned from 14 until 24-weeks-old. Trabecular metaphyseal and cortical midshaft morphometric properties, and bone mineral content (BMC) in 40 different regions of the tibia were measured. Mice treated only with loading showed the highest trabecular bone volume fraction at week 22. Cortical thickness was higher with co-treatment than in the mice treated with PTH alone. In the mid-diaphysis, increases in BMC were significantly higher with loading than PTH. In ovariectomised mice, the osteogenic benefits of co-treatment on the trabecular bone were lower than loading alone. However, combined interventions had increased, albeit regionally-dependent, benefits to cortical bone. Increased benefits were largest in the mid-diaphysis and postero-laterally, regions subjected to higher strains under compressive loads

Magnetic switching of ferroelectric domains at room temperature in multiferroic PZTFT

Single-phase magnetoelectric multiferroics are ferroelectric materials that display some form of magnetism. In addition, magnetic and ferroelectric order parameters are not independent of one another. Thus, the application of either an electric or magnetic field simultaneously alters both the electrical dipole configuration and the magnetic state of the material. The technological possibilities that could arise from magnetoelectric multiferroics are considerable and a range of functional devices has already been envisioned. Realising these devices, however, requires coupling effects to be significant and to occur at room temperature. Although such characteristics can be created in piezoelectric-magnetostrictive composites, to date they have only been weakly evident in single-phase multiferroics. Here in a newly discovered room temperature multiferroic, we demonstrate significant room temperature coupling by monitoring changes in ferroelectric domain patterns induced by magnetic fields. An order of magnitude estimate of the effective coupling coefficient suggests a value of ~1 × 10(−7) sm(−1)

Revisi\uf3n - Serradela amarilla ( Ornithopus compressus ) y serradela rosada (o. sativus): dos nuevas especies de leguminosas forrajeras anuales para la zona Mediterr\ue1nea de Chile

Yellow serradella ( Ornithopus compressus L.) and pink serradella ( Ornithopus sativus Brot.) are two new annual foragelegume species for infertile, acidic, and light texture soils, in dryland areas of the Mediterranean zone of Chile. Seven cultivars of yellow serradella and one cultivar of pink serradella, developed bytheCenter for Legumes in Mediterranean Agriculture (CLIMA),Australia, were characterized. O. compressus presented a high to medium hardseededness (53 to 100% at the beginning of the second growth season), while O. sativus presented a very low hardseededness (4%). A variable range of precocity was detected (108 to 143 days to flowering). The growth habit is semi-erect to erect, flowers are yellow in O. compressus and pink in O. sativus. The dry matter and seed production is comparable, and in some years superior, to that of species of traditional use in these areas, like subterranean clover ( Trifolium subterraneum L.) and hualputra ( Medicago polymorpha L.), standing out serradellas especially for their high production in infertile soils of the interior dry lands of Cauquenes, in the third year of evaluation (2200 to 4200 kg DM ha-1, 650 to 1440 kg seeds ha-1) The available phenological and productive data allow to think that the development of pastures based on serradellas, could mean an important contribution to the improvement of the pastoral production of extensive marginal areas of the non-irrigated Mediterranean land of Chile.La serradela amarilla ( Ornithopus compressus L.) y la serradela rosada ( Ornithopus sativus Brot.) son dos nuevas especies de leguminosas forrajeras anuales para suelos \ue1cidos inf\ue9rtiles, de texturas livianas, en zonas de secano mediterr\ue1neo de Chile. Se caracterizaron siete cultivares de serradela amarilla y uno de serradela rosada, desarrollados por el Centre for Legumes in Mediterranean Agriculture (CLIMA) de Australia. O. compressus present\uf3 una dureza seminal media a alta (53 a 100% al inicio de la segunda temporada de crecimiento), mientras que O. sativus present\uf3 una dureza seminal muy baja (4%). Se detect\uf3 un rango de precocidad variable (entre 108 y 143 d\uedas a floraci\uf3n). El h\ue1bito de crecimiento fue semi-erecto a erecto, flores de color amarillo en el caso de O. compressus y rosadas en el caso de O. sativus. La producci\uf3n de materia seca y de semillas fue comparable, y en algunos a\uf1os superior, al de las especies de uso tradicional en estas zonas, como tr\ue9bol subterr\ue1neo ( Trifolium subterraneum L.) y hualputra ( Medicago polymorpha L.), destac\ue1ndose las serradelas por su alta producci\uf3n, especialmente en suelos inf\ue9rtiles del secano interior de Cauquenes, al tercer a\uf1o de evaluaci\uf3n (2200-4200 kg MS ha-1, 650-1440 kg semilla ha-1). Los antecedentes de fenolog\ueda y comportamiento productivo permiten vislumbrar que el desarrollo de praderas en base a serradelas, podr\ueda significar un importante aporte al mejoramiento de la producci\uf3n pastoral de extensas \ue1reas marginales del secano mediterr\ue1neo de Chile

Observational Study of the Multistructured Planetary Nebula NGC 7354

We present an observational study of the planetary nebula (PN) NGC 7354 consisting of narrowband Halpha and [NII]6584 imaging as well as low- and high-dispersion long-slit spectroscopy and VLA-D radio continuum. According to our imaging and spectroscopic data, NGC 7354 has four main structures: a quite round outer shell and an elliptical inner shell, a collection of low-excitation bright knots roughly concentrated on the equatorial region of the nebula, and two symmetrical jet-like features, not aligned either with the shells' axes, or with each other. We have obtained physical parameters like electron temperature and electron density as well as ionic and elemental abundances for these different structures. Electron temperature and electron density slightly vary throughout the nebula. The local extinction coefficient c_Hbeta shows an increasing gradient from south to north and a decreasing gradient from east to west consistent with the number of equatorial bright knots present in each direction. Abundance values show slight internal variations but most of them are within the estimated uncertainties. In general, abundance values are in good agreement with the ones expected for PNe. Radio continuum data are consistent with optically thin thermal emission. We have used the interactive three-dimensional modeling tool SHAPE to reproduce the observed morphokinematic structures in NGC 7354 with different geometrical components. Our SHAPE model is in very good agreement with our imaging and spectroscopic observations. Finally, after modeling NGC 7354 with SHAPE, we suggest a possible scenario for the formation of the nebula.Comment: Accepted for publication in AJ, 12 pages, 8 figure

Cost of tuberculosis treatment in low- and middle-income countries: systematic review and meta-regression.

BACKGROUND: Despite a scarcity of tuberculosis (TB) cost data, a substantial body of evidence has been accumulating for drug-susceptible TB (DS-TB) treatment. In this study, we review unit costs for DS-TB treatment from a provider´s perspective. We also examine factors driving cost variations and extrapolate unit costs across low- and middle-income countries (LMICs).METHODS: We searched published and grey literature for any empirically collected TB cost estimates. We selected a subgroup of estimates looking at DS-TB treatment. We extracted information on activities and inputs included. We standardised costs into an average per person-month, fitted a multi-level regression model and cross-validated country-level predictions. We then extrapolated estimates for facility-based, directly observed DS-TB treatment across countries.RESULTS: We included 95 cost estimates from 28 studies across 17 countries. Costs predictions were sensitive to characteristics such as delivery mode, whether hospitalisation was included, and inputs accounted for, as well as gross domestic product per capita. Extrapolation results are presented with uncertainty intervals (UIs) for LMICs. Predicted median costs per 6 months of treatment were US$315.30 (95$222.60-US$417.20) for low-income, US$527.10 (95% CI US$395.70-US$743.70) for lower middle-income and US$896.40 (95$654.00-US$1214.40) for upper middle-income countries.CONCLUSIONS: Our study provides country-level DS-TB treatment cost estimates suitable for priority setting. These estimates, while not standing as a substitute for local high-quality primary data, can inform global, regional and national exercises