Spectrum Focused Frequency Adversarial Attacks for Automatic Modulation Classification

Artificial intelligence (AI) technology has provided a potential solution for automatic modulation recognition (AMC). Unfortunately, AI-based AMC models are vulnerable to adversarial examples, which seriously threatens the efficient, secure and trusted application of AI in AMC. This issue has attracted the attention of researchers. Various studies on adversarial attacks and defenses evolve in a spiral. However, the existing adversarial attack methods are all designed in the time domain. They introduce more high-frequency components in the frequency domain, due to abrupt updates in the time domain. For this issue, from the perspective of frequency domain, we propose a spectrum focused frequency adversarial attacks (SFFAA) for AMC model, and further draw on the idea of meta-learning, propose a Meta-SFFAA algorithm to improve the transferability in the black-box attacks. Extensive experiments, qualitative and quantitative metrics demonstrate that the proposed algorithm can concentrate the adversarial energy on the spectrum where the signal is located, significantly improve the adversarial attack performance while maintaining the concealment in the frequency domain.Comment: 6 pages, 9 figure

High Genetic Diversity of HIV-1 and Active Transmission Clusters among Male-to-Male Sexual Contacts (MMSCs) in Zhuhai, China

Monitoring genetic diversity and recent HIV infections (RHIs) is critical for understanding HIV epidemiology. Here, we report HIV-1 genetic diversity and RHIs in blood samples from 190 HIV-positive MMSCs in Zhuhai, China. MMSCs with newly reported HIV were enrolled from January 2020 to June 2022. A nested PCR was performed to amplify the HIV polymerase gene fragments at HXB2 positions 2604–3606. We constructed genetic transmission network at both 0.5% and 1.5% distance thresholds using the Tamura-Nei93 model. RHIs were identified using a recent infection testing algorithm (RITA) combining limiting antigen avidity enzyme immunoassay (LAg-EIA) assay with clinical data. The results revealed that 19.5% (37/190) were RHIs and 48.4% (92/190) were CRF07_BC. Two clusters were identified at a 0.5% distance threshold. Among them, one was infected with CRF07_BC for the long term, and the other was infected with CRF55_01B recently. We identified a total of 15 clusters at a 1.5% distance threshold. Among them, nine were infected with CRF07_BC subtype, and RHIs were found in 38.8% (19/49) distributed in eight genetic clusters. We identified a large active transmission cluster (n = 10) infected with a genetic variant, CRF79_0107. The multivariable logistic regression model showed that clusters were more likely to be RHIs (adjusted OR: 3.64, 95% CI: 1.51~9.01). The RHI algorithm can help to identify recent or ongoing transmission clusters where the prevention tools are mostly needed. Prompt public health measures are needed to contain the further spread of active transmission clusters

Novel multimodal approaches to analysing cellular environments

The cell has a rich and complex environment. Understanding the biochemical changes inside a cell and its organelles is key to the understanding of healthy and diseased states. Different tools have emerged to visualise the cell. However, a single technique reports on a singular aspect of the cellular environment, and it can be difficult to obtain a full view of the cellular environment. Multimodal imaging can provide a more holistic understanding of the cell, due to the correlation of information from different techniques. This provides complementary information about the biochemical environment of the cell, and also cross-validates results from each individual mode. While multimodal imaging emerged as an area of research in recent times, few studies have focused on the combination of fluorescence microscopy, Raman and X-ray fluorescence microscopy (XFM) techniques. As these techniques have different modes of action and sensitivities, there are some intrinsic challenges in developing probes that can report successfully in each modality. The work in this thesis has aimed to develop multimodal probes for these three modalities. Chapter 2 describes the development of a bimodal fluorescence-Raman probe, NpCN1, a fluorescent naphthalimide-based probe with a nitrile Raman tag. NpCN1 was used to successfully image the lipid droplets in both modalities. Chapter 3 describes the development of the trimodal fluorescence-Raman-XFM probe, NpCNBr1. This probe was also a napthalimide-based fluorophore with a nitrile Raman tag, with Br added as an XFM recognition moiety. NpCNBr1 also localised in the lipid droplets, and chemical composition of the organelle environment was characterised using each of the modalities. Chapter 4 describes work towards multimodal systems that could produce a change in output signal in each modality after interaction with analytes of interest, and probes targeted to subcellular organelles

Research and analysis of Olympic venue development and utilization: Based on the examples of Barcelona, Sydney, Beijing and Rio Olympic venues

In every Olympic Games, those huge and beautiful Olympic venues are their unique symbols. However, after the revelry of the Olympic feast, the post-game operation of these venues has coincidentally become a worldwide problem. The huge volume of these Olympic venues, the huge maintenance cost, the difficulty of function development and the lack of utilization rate all make their reasonable operation another difficult and time-consuming challenge. Modern Olympic Games are accompanied by massive stadiums and Olympic parks, leading to increasing difficulties in the development and utilization of the venues after the games. This makes it necessary for the host city to consider the post-game development and utilization of the venues during the bidding and construction period of the Olympic Games. In many Olympic Games in the past, because the post-game development and utilization of the venues were not considered at the early stage of construction, the Olympic venues could not be reasonably utilized after the games, and the host cities were put into a heavy financial burden. The purpose of the research provides a theoretical basis and reference for improving the development and utilization of the existing and future Olympic venues through the research and analysis of the post-match development and utilization of the Barcelona, Sydney, Beijing, and Rio Olympic venues. The research takes the 1992 Barcelona Olympics, 2002 Sydney Olympics, 2008 Beijing Olympics and 2016 Rio Olympics as the research objects. Based on the definition of the Olympic venues, the definition of the development and utilization of the Olympic venues, and the historical evolution of the Olympic venues, the construction and competition of the Barcelona, Sydney, Beijing, and Rio Olympics are analysed through the publication of literature and comparative analysis methods. The history, current situation and characteristics of post-development and utilization. In response to related issues, the following suggestions are put forward: 1. Adopt a model of government-enterprise cooperation; 2. Undertake professional sports competitions; 3. Adopt a diversified operation model; 4. Introduce a professional management team; 5. Develop the public sports industry

Dietary Methionine Requirements of Pacific White Shrimp Litopenaeus vannamei, of Three Different Sizes

Three feeding trials were conducted to determine the dietary methionine requirements for Litopenaeus vannamei of three different sizes, small (0.55±0.01g), medium (4.18±0.05g), and large (9.77±0.08g). Seven diets were formulated with seven different levels of methionine (0, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, or 0.6%). The greatest weight gain (WG) and specific growth rate (SGR) of small and large shrimp were observed when dietary methionine levels were 0.8%, and 0.71%, respectively (P<0.05). The highest survival rate of small and large shrimp was observed when dietary methionine levels were 0.97%, and 1.07%, respectively (P<0.05). For small and medium shrimp, the optimal dietary methionine level for maximum weight gain estimated by quadratic regression analysis was 0.91% and 0.67% of dry diet, respectively. For large shrimp, the optimal dietary methionine requirement estimated by broken-line model based on weight gain was 0.66% of dry diet

Strategies for organelle targeting of fluorescent probes

Fluorescent tools have emerged as an important tool for studying the distinct chemical microenvironments of organelles, due to their high specificity and ability to be used in non-destructive, live cellular studies. These tools fall largely in two categories: exogenous fluorescent dyes, or endogenous labels such as genetically encoded fluorescent proteins. In both cases, the probe must be targeted to the organelle of interest. To date, many organelle-targeted fluorescent tools have been reported and used to uncover new information about processes that underpin health and disease. However, the majority of these tools only apply a handful of targeting groups, and less-studied organelles have few robust targeting strategies. While the development of new, robust strategies is difficult, it is essential to develop such strategies to allow for the development of new tools and broadening the effective study of organelles. This review aims to provide a comprehensive overview of the major targeting strategies for both endogenous and exogenous fluorescent cargo, outlining the specific challenges for targeting each organelle type and as well as new developments in the field

A network meta-analysis on responses of forest soil carbon concentration to interventions

Abstract Background Forests play a crucial role in absorbing CO2 from the atmosphere. 55% of the carbon in terrestrial ecosystems is stored in forests, with the majority of forest carbon stored in soil. To better understand soil organic carbon (SOC) of forests and to access interventions that affect their SOC concentration, we conducted a comparative analysis between natural and planted forests. Forest interventions refer to the actions taken by humans to manage, protect, or transform forests, and can be divided into two main categories: environmental intervention and anthropogenic intervention. This study focused on the effects of different interventions on SOC in natural and planted forests by reviewing a total of 75 randomized controlled trials in the global literature and extracting a total of 15 different interventions. Results Through network meta-analysis, we found that natural forests have 22.3% higher SOC than planted forests, indicating their stronger carbon storage function. In natural forests, environmental interventions have a stronger impact. SOC is significantly influenced by forest age, fertilization, and elevation. In planted forests, however, anthropogenic interventions have a stronger impact. Pruning branches and fertilization are effective interventions for planted forests. Furthermore, forest degradation has a significantly negative impact on SOC in planted forests. Conclusion Overall, interventions to enhance soil carbon storage function differ between natural and planted forests. To address global climate change, protect biodiversity, and achieve sustainable development, it is imperative to globally protect forests and employ scientifically sound forest management practices. Regarding natural forests, the emphasis should be on comprehending the effects of environmental interventions on SOC. Conversely, concerning planted forests, the emphasis should be on comprehending the effects of anthropogenic interventions

A Bimodal Fluorescence-Raman Probe for Cellular Imaging

Biochemical changes in specific organelles underpin cellular function, and studying these changes is crucial to understand health and disease. Fluorescent probes have become important biosensing and imaging tools as they can be targeted to specific organelles and can detect changes in their chemical environment. However, the sensing capacity of fluorescent probes is highly specific and is often limited to a single analyte of interest. A novel approach to imaging organelles is to combine fluorescent sensors with vibrational spectroscopic imaging techniques; the latter provides a comprehensive map of the relative biochemical distributions throughout the cell to gain a more complete picture of the biochemistry of organelles. We have developed NpCN1, a bimodal fluorescence-Raman probe targeted to the lipid droplets, incorporating a nitrile as a Raman tag. NpCN1 was successfully used to image lipid droplets in 3T3-L1 cells in both fluorescence and Raman modalities, reporting on the chemical composition and distribution of the lipid droplets in the cells