Collective oscillations in quantum rings: a broken symmetry case

We present calculations within density functional theory of the ground state and collective electronic oscillations in small two-dimensional quantum rings. No spatial symmetries are imposed to the solutions and, as in a recent contribution, a transition to a broken symmetry solution in the intrinsic reference frame for an increasingly narrow ring is found. The oscillations are addressed by using real-time simulation. Conspicuous effects of the broken symmetry solution on the spectra are pointed out.Comment: ReVTeX, 5 embedded eps, two gifs. Accepted in EPJ

Investment needs for irrigation infrastructure along different socio-economic pathways

This paper conducts an assessment of the global costs for expanding, upgrading, and improving irrigation infra-structure in developing countries, along different future scenarios toward 2050. It uses the GLobal BIOsphere Man-agement Model, a partial equilibrium model of the global agricultural and forestry sectors. It examines the impacts of irrigation expansion on the agriculture and food system, from the perspective of different Sustainable Development Goals, in particular food security (goal 2), land use change and biodiversity (goal 15), greenhouse gas emissions (goal 13), and sustainable water use (goal 6). It finds that irriga-tion support policies improve food security globally and can reduce the burden on land by limiting expansion of cropland area. However, the effectiveness of irrigation to achieve a larger set of goals depends on the regional con-text. In South Asia and the Middle East and North Africa, the expansion of irrigation increases unsustainable water extraction practices. A sensitivity analysis is conducted to evaluate the uncertainty of the infrastructure costs and impacts under different socioeconomic developments, levels of radiative forcing and climate change scenarios, dietary patterns, trade openness, and efficiencies of irriga-tion systems. The findings indicate that irrigation systems could play an important role in adaptation to the most adverse climate change; however, increased water scarcity may also limit adaptation potentials

Briquetagem de biomassa florestal: variáveis do processo e qualidade do produto.

EVINCI. Resumo

NoLACE: Improving Low-Complexity Speech Codec Enhancement Through Adaptive Temporal Shaping

Speech codec enhancement methods are designed to remove distortions added by speech codecs. While classical methods are very low in complexity and add zero delay, their effectiveness is rather limited. Compared to that, DNN-based methods deliver higher quality but they are typically high in complexity and/or require delay. The recently proposed Linear Adaptive Coding Enhancer (LACE) addresses this problem by combining DNNs with classical long-term/short-term postfiltering resulting in a causal low-complexity model. A short-coming of the LACE model is, however, that quality quickly saturates when the model size is scaled up. To mitigate this problem, we propose a novel adatpive temporal shaping module that adds high temporal resolution to the LACE model resulting in the Non-Linear Adaptive Coding Enhancer (NoLACE). We adapt NoLACE to enhance the Opus codec and show that NoLACE significantly outperforms both the Opus baseline and an enlarged LACE model at 6, 9 and 12 kb/s. We also show that LACE and NoLACE are well-behaved when used with an ASR system.Comment: submitted to ICASSP 202