450 research outputs found

    Salt Secretion Is Essential for Xero-Halophyte \u3cem\u3eReaumuria soongorica\u3c/em\u3e Responding to Osmotic Stress

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    Reaumuria soongorica, a xero-halophyte semi-shrub belonging to Tamaricaceae with excellent adaptability to adverse arid and salinity environments of northwest China, serves important ecological roles in the improvement of saline-alkali soil and dune stabilisation, and also is an attractive fodder shrub in desert steppe (Ma et al. 2011). Previous studies demonstrated that secreting salt via salt glands is an important strategy for R. soongorica adapting to high salinity environments (Zhou et al. 2012). However, very little is known about the role of salt secretion in the plant’s responses to drought. Therefore, in the present work, R. soongorica seedlings were subjected to osmotic stress in the presence or absence of additional NaCl to determine the potential relationship between salt secretion and drought tolerance of R. soongorica seedlings

    Quantum anti-Zeno effect without rotating wave approximation

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    In this paper, we systematically study the spontaneous decay phenomenon of a two-level system under the influences of both its environment and continuous measurements. In order to clarify some well-established conclusions about the quantum Zeno effect (QZE) and the quantum anti-Zeno effect (QAZE), we do not use the rotating wave approximation (RWA) in obtaining an effective Hamiltonian. We examine various spectral distributions by making use of our present approach in comparison with other approaches. It is found that with respect to a bare excited state even without the RWA, the QAZE can still happen for some cases, e.g., the interacting spectra of hydrogen. But for a physical excited state, which is a renormalized dressed state of the atomic state, the QAZE disappears and only the QZE remains. These discoveries inevitably show a transition from the QZE to the QAZE as the measurement interval changes.Comment: 14 pages, 8 figure

    Consistent Attack: Universal Adversarial Perturbation on Embodied Vision Navigation

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    Embodied agents in vision navigation coupled with deep neural networks have attracted increasing attention. However, deep neural networks have been shown vulnerable to malicious adversarial noises, which may potentially cause catastrophic failures in Embodied Vision Navigation. Among different adversarial noises, universal adversarial perturbations (UAP), i.e., a constant image-agnostic perturbation applied on every input frame of the agent, play a critical role in Embodied Vision Navigation since they are computation-efficient and application-practical during the attack. However, existing UAP methods ignore the system dynamics of Embodied Vision Navigation and might be sub-optimal. In order to extend UAP to the sequential decision setting, we formulate the disturbed environment under the universal noise δ\delta, as a δ\delta-disturbed Markov Decision Process (δ\delta-MDP). Based on the formulation, we analyze the properties of δ\delta-MDP and propose two novel Consistent Attack methods, named Reward UAP and Trajectory UAP, for attacking Embodied agents, which consider the dynamic of the MDP and calculate universal noises by estimating the disturbed distribution and the disturbed Q function. For various victim models, our Consistent Attack can cause a significant drop in their performance in the PointGoal task in Habitat with different datasets and different scenes. Extensive experimental results indicate that there exist serious potential risks for applying Embodied Vision Navigation methods to the real world

    APCodec: A Neural Audio Codec with Parallel Amplitude and Phase Spectrum Encoding and Decoding

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    This paper introduces a novel neural audio codec targeting high waveform sampling rates and low bitrates named APCodec, which seamlessly integrates the strengths of parametric codecs and waveform codecs. The APCodec revolutionizes the process of audio encoding and decoding by concurrently handling the amplitude and phase spectra as audio parametric characteristics like parametric codecs. It is composed of an encoder and a decoder with the modified ConvNeXt v2 network as the backbone, connected by a quantizer based on the residual vector quantization (RVQ) mechanism. The encoder compresses the audio amplitude and phase spectra in parallel, amalgamating them into a continuous latent code at a reduced temporal resolution. This code is subsequently quantized by the quantizer. Ultimately, the decoder reconstructs the audio amplitude and phase spectra in parallel, and the decoded waveform is obtained by inverse short-time Fourier transform. To ensure the fidelity of decoded audio like waveform codecs, spectral-level loss, quantization loss, and generative adversarial network (GAN) based loss are collectively employed for training the APCodec. To support low-latency streamable inference, we employ feed-forward layers and causal convolutional layers in APCodec, incorporating a knowledge distillation training strategy to enhance the quality of decoded audio. Experimental results confirm that our proposed APCodec can encode 48 kHz audio at bitrate of just 6 kbps, with no significant degradation in the quality of the decoded audio. At the same bitrate, our proposed APCodec also demonstrates superior decoded audio quality and faster generation speed compared to well-known codecs, such as SoundStream, Encodec, HiFi-Codec and AudioDec.Comment: Submitted to IEEE/ACM Transactions on Audio, Speech, and Language Processin

    Modeling and Analysis of MIMO Multipath Channels with Aerial Intelligent Reflecting Surface

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    LESSON STUDY: AMALAN BERKOLABORASI UNTUK PEMBELAJARAN BERKESAN DI INSTITUT PENDIDIKAN GURU

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    Penyelidikan ini bertujuan untuk melihat keberkesananLesson Study terhadap peningkatan pencapaian guru pelatih dalam pemahaman konsep utama Pembelajaran Berasaskan Inkuiri dalam topik Model Pembelajaran Sosial.Seramai sembilan pensyarah Jabatan Ilmu Pendidikan beserta dua puluh orang guru pelatih dari Institut Pendidikan Guru Kampus Ipoh terlibat dalam pelaksanaan Lesson Study ini.  Pengumpulan data seperti soalan kuiz awalan dan akhir dikendalikan untuk mengukur pencapaian guru pelatih.  Analisis terhadap dokumen exit card juga dilaksanakan di mana analisis respon yang diberikan oleh guru-guru pelatih dikumpul, dianalisis dan diinterpretasikan mengikut tema.  Dapatan menunjukkan 60% daripada guru pelatih menunjukkan peningkatan dalam pencapaian soalan kuiz mereka.  Dapatan analisis exit card menunjukkan responden sendiri memaklumkan mereka telah memahami konsep utama yang diajar dalam Lesson Study dan dapat memberikan sumbangan idea dalam aktiviti gallery tour.  Mereka berasa gembira dan juga berpuas hati kerana dapat melibatkan diri secara aktif dalam satu sesi Lesson Study yang menarik
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