South Bay Interdisciplinary Science Center

We provide a systematic and self-consistent method to calculate the generalized Brillouin zone (GBZ) analytically in one-dimensional non-Hermitian systems, which helps us to understand the non-Hermitian bulk-boundary correspondence. In general, a n-band non-Hermitian Hamiltonian is constituted by n distinct sub-GBZs, each of which is a piecewise analytic closed loop. Based on the concept of resultant, we can show that all the analytic properties of the GBZ can be characterized by an algebraic equation, the solution of which in the complex plane is dubbed as auxiliary GBZ (aGBZ). We also provide a systematic method to obtain the GBZ from aGBZ. Two physical applications are also discussed. Our method provides an analytic approach to the spectral problem of open boundary non-Hermitian systems in the thermodynamic limit.

The fermion doubling theorem plays a pivotal role in Hermitian topological materials. It states, for example, that Weyl points must come in pairs in three-dimensional semimetals. Here, we present an extension of the doubling theorem to non-Hermitian lattice Hamiltonians. We focus on two-dimensional non-Hermitian systems without any symmetry constraints, which can host two different types of topological point nodes, namely, (i) Fermi points and (ii) exceptional points. We show that these two types of protected point nodes obey doubling theorems, which require that the point nodes come in pairs. To prove the doubling theorem for exceptional points, we introduce a generalized winding number invariant, which we call the "discriminant number." Importantly, this invariant is applicable to any two-dimensional non-Hermitian Hamiltonian with exceptional points of arbitrary order and, moreover, can also be used to characterize nondefective degeneracy points. Furthermore, we show that a surface of a three-dimensional system can violate the non-Hermitian doubling theorems, which implies unusual bulk physics.

Topological nodal line semimetals host stable chained, linked, or knotted line degeneracies in momentum space protected by symmetries. In this Letter, we use the Jones polynomial as a general topological invariant to capture the global knot topology of the oriented nodal lines. We show that every possible change in Jones polynomial is attributed to the local evolutions around every point where two nodal lines touch. As an application of our theory, we show that nodal chain semimetals with four touching points can evolve to a Hopf link. We extend our theory to 3D non-Hermitian multiband exceptional line semimetals. Our work provides a recipe to understand the transition of the knot topology for protected nodal lines.

We study vortex bound states in three-dimensional (3D) superconducting Dirac semimetals with time reversal symmetry. We find that there exist robust gapless vortex bound states propagating along the vortex line in the s-wave superconducting state. We refer to this newly found phase as the quasi-1D nodal vortex line phase. According to the Altland-Zirnbauer classification, the phase is characterized by a topological index (ν;N) at k_{z}=0 and k_{z}=π, where ν is the Z_{2} topological invariant for a 0D class-D system and N is the Z topological invariant for a 0D class-A system. Furthermore, we show that the vortex end Majorana zero mode can coexist with the quasi-1D nodal phase in certain types of Dirac semimetals. The possible experimental observations and material realization of such nodal vortex line states are discussed.

We study a realistic Floquet topological superconductor, a periodically driven nanowire proximitized to an equilibrium s-wave superconductor. Because of the strong energy and density fluctuations caused by the superconducting proximity effect, the Floquet Majorana wire becomes dissipative. We show that the Floquet band structure is still preserved in this dissipative system. In particular, we find that the Floquet Majorana zero and π modes can no longer be simply described by the Floquet topological band theory. We also propose an effective model to simplify the calculation of the lifetime of these Floquet Majoranas and find that the lifetime can be engineered by the external driving field.

The ternary AMnBi_{2} (A is alkaline as well as rare-earth atom) materials provide an arena for investigating the interplay between low-dimensional magnetism of the antiferromagnetic MnBi layers and the electronic states in the intercalated Bi layers, which harbor relativistic fermions. Here, we report on a comprehensive study of the optical properties and magnetic torque response of Ca_{1-x}Na_{x}MnBi_{2}. Our findings give evidence for a spin canting occurring at T_{s}∼50-100 K. With the support of first-principles calculations we establish a direct link between the spin canting and the reconstruction of the electronic band structure, having immediate implications for the spectral weight reshuffling in the optical response, signaling a partial gapping of the Fermi surface, and the dc transport properties below T_{s}.

An important function in purchasing is the disposal of excess material. Often the material is in the form of waste products such as paper, metals and plastics which are difficult to value. However, by utilizing a commodity‐market based approach, many items can now be disposed of in a timely, profitable and environmentally friendly manner. This paper discusses some of the issues involved in disposing of surplus material using commodity indices. The discussion also shows how surplus asset disposal is linked to developments in environmental logistics, reverse logistics and recycling. The general methods, issues and challenges in commodity disposal have been explained through a case study. The case study includes a total cost model showing the costs and the benefits of commodity based or commodity indexed disposal.

We report an optical spectroscopy study of a single-crystal sample of PrSb, one of the monoantimonide $R\mathrm{Sb}$ compounds, which show interesting properties, such as topological nontrivial surface states and extremely large magnetoresistance. The plasma frequency is revealed at about $4300\phantom{\rule{0.28em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$, suggesting a low carrier density. In addition, we found two quasilinear components with variable slopes in the real part of the optical conductivity ${\ensuremath{\sigma}}_{1}(\ensuremath{\omega})$. In combination with theoretical calculations which reveal a band inversion, our results may provide optical spectroscopic evidence of a topological nontrivial property in PrSb.

, and independent of the maternal-zygotic transition dynamics.

Developing electrocatalysts that exhibit exceptional activity without relying on noble metals, all while ensuring high efficiency and durability for the oxygen reduction and evolution reactions, poses a challenging yet highly desired task. Monodispersed nanoparticles on a conductive framework through strong metal–support interactions are known to show excellent catalytic performance. Herein, monodispersed iron selenide embedded in a carbon nanotube network is synthesized. Graphitic carbon shells enclosing monodispersed iron selenide address the primary challenge of nanoparticle catalysts—aggregation and corrosion of nanoparticles over repeated oxygen redox reactions. By amplifying the interaction of Fe with carbon nanotubes, the heterogeneous catalyst forms highly active centers for oxygen redox reaction from the coordinated iron atoms, along with conductive iron–nitrogen–carbon nanotube pathways for rapid charge transfer. As a result, the heterogeneous catalyst exhibits superior activity for both oxygen reduction ( E 1/2 = 0.88 V) and oxygen evolution ( η = 360 mV@10 mA cm −2 ) and excellent stability of negligible degradation over 5000 cycles. The overall catalytic performance surpasses the noble metals. Therefore, rechargeable zinc–air batteries using the heterogeneous catalyst exhibit a high power density of 130.9 mW cm −2 , excellent round‐trip efficiency of ≈70%, and cycling stability for over 1100 h at 10 mA cm −2 .

Rechargeable Zn–Air Batteries In article number 2400181, Yang Huang, Minshen Zhu, Shuiliang Chen, and co-workers develop a 3D Fe–Se@N-CNTs catalyst with monodispersed FeSe2 nanoparticles in nitrogen-doped carbon nanotubes, showing excellent ORR/OER activity and stability. This advanced non-noble metal catalyst allows for zinc–air batteries to achieve high power density, efficiency, and extended cycling stability.

Cell polarization is a critical process that separates molecular species into two distinct regions in prokaryotic and eukaryotic cells, guiding biological processes such as cell division and cell differentiation. Although several underlying antagonistic reaction-diffusion networks capable of setting up cell polarization have been identified experimentally and theoretically, our understanding of how to manipulate pattern stability and asymmetry remains incomplete, especially when only a subset of network components is known. Here, we present numerical results to show that the polarized pattern of an antagonistic 2-node network collapses into a homogeneous state when subjected to single-sided self-regulation, single-sided additional regulation, or unequal system parameters. However, polarity restoration can be achieved by combining two modifications with opposing effects. Additionally, spatially inhomogeneous parameters favoring respective domains stabilize their interface at designated locations. To connect our findings to cell polarity studies of the nematode Caenorhabditis elegans zygote, we reconstituted a 5-node network where a 4-node circuit with full mutual inhibitions between anterior and posterior is modified by a mutual activation in the anterior and an additional mutual inhibition between the anterior and posterior. Once again, a generic set of kinetic parameters moves the interface towards either the anterior or posterior end, yet a polarized pattern can be stabilized through tuning of one or more parameters coupled to intracellular or extracellular spatial cues. A user-friendly software, PolarSim , is constructed to facilitate the exploration of networks with alternative node numbers, parameter values, and regulatory pathways.

Objetivou-se determinar a composição centesimal de diferentes cortes da carcaça, sendo 03 (três) filés de peito de frango, 03 (três) patinhos de ovino, 03 (três) contra-filés bovino e 03 (três) picanhas suína. A porção comestível do contra-filé bovino foi a que apresentou maior teor de gordura total, enquanto que o filé de peito de frango apresentou maior teor de proteína. A atividade de água nos cortes foi semelhante, com destaque para a carne ovina, a carne de frango apresentou maior luminosidade e com tendência para o tom amarelo, enquanto a carne bovina apresentou os tons mais vermelhos.

Cell polarization is a critical process that separates molecular species into two distinct regions in prokaryotic and eukaryotic cells, guiding biological processes such as cell division and cell differentiation. Although several underlying antagonistic reaction-diffusion networks capable of setting up cell polarization have been identified experimentally and theoretically, our understanding of how to manipulate pattern stability and asymmetry remains incomplete, especially when only a subset of network components is known. Here, we present numerical results to show that the polarized pattern of an antagonistic 2-node network collapses into a homogeneous state when subjected to single-sided self-regulation, single-sided additional regulation, or unequal system parameters. However, polarity restoration can be achieved by combining two modifications with opposing effects. Additionally, spatially inhomogeneous parameters favoring respective domains stabilize their interface at designated locations. To connect our findings to cell polarity studies of the nematode Caenorhabditis elegans zygote, we reconstituted a 5-node network where a 4-node circuit with full mutual inhibitions between anterior and posterior is modified by a mutual activation in the anterior and an additional mutual inhibition between the anterior and posterior. Once again, a generic set of kinetic parameters moves the interface towards either the anterior or posterior end, yet a polarized pattern can be stabilized through tuning of one or more parameters coupled to intracellular or extracellular spatial cues. A user-friendly software, PolarSim , is constructed to facilitate the exploration of networks with alternative node numbers, parameter values, and regulatory pathways.

Cell polarization is a critical process that separates molecules into two distinct regions in prokaryotic and eukaryotic cells, guiding biological processes such as cell division and cell differentiation. Although several underlying antagonistic reaction-diffusion networks capable of setting up cell polarization have been identified experimentally and theoretically, our understanding of how to manipulate pattern stability and asymmetry remains incomplete, especially when only a subset of network components are known. Here we present numerical results to show that the polarized pattern of an antagonistic 2-node network collapses into a homogeneous state when subjected to single-sided self-regulation, single-sided additional regulation, or unequal system parameters. However, polarity can be restored through a combination of two modifications that have opposing effects. Additionally, spatially inhomogeneous parameters favoring respective domains stabilize their interface at designated locations. To connect our findings to cell polarity studies of the nematode Caenorhabditis elegans zygote, we reconstituted a 5-node network where a 4-node circuit with full mutual inhibitions between anterior and posterior is modified by a mutual activation in the anterior and an additional mutual inhibition between the anterior and the posterior. Once again, a generic set of kinetic parameters moves the interface towards either the anterior or posterior end, yet a polarized pattern can be stabilized through spatial tuning of one or more parameters coupled to intracellular or extracellular cues. A user-friendly software, PolarSim, is introduced to facilitate the exploration of networks with alternative node numbers, parameter values, and regulatory pathways.

As Unidades de Terapia Intensiva destinam-se ao cuidado de pacientes em estado crítico que, na maioria das vezes, não são capazes de desempenhar atividades de autocuidado, como a higiene corporal e oral. É indispensável lembrar que os pacientes críticos necessitam de constante monitoramento  dos  sinais  vitais  e  assistência  contínua  e  sistemática.  Para  diminuir  os  riscos  e melhorar o conforto dos pacientes, as intervenções de Enfermagem devem ser executadas de forma padronizada, por profissionais capacitados e baseada em evidências científicas. Embora a execução das técnicas de higiene oral e corporal corretas seja essencial e de grande relevância, observa-se que a padronização da técnica é, muitas vezes, banalizada na rotina do serviço.

Abstract Cell polarization is a critical process that separates molecular species into two distinct regions in prokaryotic and eukaryotic cells, guiding biological processes such as cell division and cell differentiation. Although several underlying antagonistic reaction-diffusion networks capable of setting up cell polarization have been identified experimentally and theoretically, our understanding of how to manipulate pattern stability and asymmetry remains incomplete, especially when only a subset of network components are known. Here we present numerical results to show that the polarized pattern of an antagonistic 2-node network collapses into a homogeneous state when subjected to single-sided self-regulation, single-sided additional regulation, or unequal system parameters. However, polarity restoration can be achieved by combining two modifications with opposing effects. Additionally, spatially inhomogeneous parameters favoring respective domains stabilize their interface at designated locations. To connect our findings to cell polarity studies of the nematode Caenorhabditis elegans zygote, we reconstituted a 5-node network where a 4-node circuit with full mutual inhibitions between anterior and posterior is modified by a mutual activation in the anterior and an additional mutual inhibition between the anterior and the posterior. Once again, a generic set of kinetic parameters moves the interface towards either the anterior or posterior end, yet a polarized pattern can be stabilized through spatial tuning of one or more parameters coupled to intracellular or extracellular cues. A user-friendly software, PolarSim, is introduced to facilitate the exploration of networks with alternative node numbers, parameter values, and regulatory pathways.