Auburn University

Clade 2.3.4.4 Eurasian lineage H5Nx highly pathogenic avian influenza virus (HPAIV) has become the globally dominant clade and caused global outbreaks since 2014. The clade 2.3.4.4 viruses have evolved into eight hemagglutinin subgroups (2.3.4.4a-h). In this study, we evaluated the infectivity, pathobiology, and transmissibility of seven clade 2.3.4.4 viruses (two 2.3.4.4a, two 2.3.4.4b, one 2.3.4.4c and two 2.3.4.4e) in chickens. The two clade 2.3.4.4e viruses caused 100% mortality and transmissibility in chickens. However, clade 2.3.4.4a and c viruses showed 80-90% mortality and 67% transmissibility. Clade 2.3.4.4b viruses showed 100% mortality, but no transmission to co-housed chickens was observed based on lack of seroconversion. All the infected chickens died showing systemic infection, irrespective of subgroup. The results highlight that all the clade 2.3.4.4 HPAIVs used in this study caused high mortality in infected chickens, but the transmissibility of the viruses in chickens was variable in contrast to that of previous Eurasian-lineage H5N1 HPAIVs. Changes in the pathogenicity and transmissibility of clade 2.3.4.4 HPAIVs warrant careful monitoring of the viruses to establish effective control strategies.

Multi-bit 3D NAND flash-based SSDs, offering high storage density, contain multiple types of pages to accommodate multiple bits per physical cell. Full sequence program or FSP can program multiple pages in a word line at a time, thereby improving write throughput. Unfortunately, large-grained FSP operations coarsely aggregate consecutive logical pages on the same word line, which adversely affects the parallelism and latency of read requests. Moreover, FSP smooths the program latencies for different types of pages, whereas the pages still exhibit various read latencies. Multiple read latencies and lower read parallelism noticeably deteriorate the completion efficiency of read requests: SSD performance is degraded. To address this issue, we propose a full sequence program data allocation scheme called FSPDA that incorporates the physical structure characteristics of multi-bit 3D NAND, aiming to bolster the read performance of 3D NAND Flash-based SSDs. FSPDA embraces two distinctive and vital features. First, according to the distance between logical pages, FSPDA allocates logical pages to specified parallel units and stipulates that consecutive logical pages must be assigned to different planes, thus improving read parallelism and data locality. Second, to further reduce read latency, FSPDA employs cache hits to determine hot and cold data to be placed to low-latency and high-latency pages, respectively. We compare FSPDA with two state-of-art schemes – OSPADA and SOML – in terms of multi-plane read counts, read response time, and GC counts under eight real-world workloads. The experimental results show that compared with the existing schemes, FSPDA slashes the number of multi-plane read counts, read response time, and the number of GC counts by an average of 34.4%, 28.5%, and 13.6%, respectively.

Malware traffic classification (MTC) plays an important role for securing the Internet of Things (IoT). Many machine learning (ML) and deep learning (DL) based MTC methods have been proposed in recent years. However, the former still requires human intervention, while the latter incurs considerable computation overheads. To address these problems, we propose a broad learning (BL) aided MTC method (BL-MTC), which is a lightweight and GPU-free solution with good performance and extremely low cost. The simulation results show that the proposed BL-MTC method not only achieves superior results on the USTC-TFC2016 dataset, but also exhibits an exponential advantage in computation overhead.

In this paper, the problem of joint communication and sensing is studied in the context of terahertz (THz) vehicular networks. In the studied model, a set of service provider vehicles (SPVs) provide either communication service or sensing service to target vehicles, where it is essential to determine 1) the service mode (i.e., providing either communication or sensing service) for each SPV and 2) the subset of target vehicles that each SPV will serve. The problem is formulated as an optimization problem aiming to maximize the sum of the data rates of the communication target vehicles, while satisfying the sensing service requirements of the sensing target vehicles, by determining the service mode and the target vehicle association for each SPV. To solve this problem, a graph neural network (GNN) based algorithm with a heterogeneous graph representation is proposed. The proposed algorithm enables the central controller to extract each vehicle’s graph information related to its location, connection, and communication interference. Using this extracted graph information, a joint service mode selection and target vehicle association strategy is then determined to adapt to the dynamic vehicle topology with various vehicle types (e.g., target vehicles and service provider vehicles). Simulation results show that the proposed GNN-based scheme can achieve 93.66% of the sum rate achieved by the optimal solution, and yield up to 3.16% and 31.86% improvements in sum rate, respectively, over a homogeneous GNN-based algorithm and a conventional optimization algorithm without using GNNs.

Serverless computing is a leading force behind deploying and managing software in cloud computing. One inherent challenge in serverless computing is the increased overall latency due to duplicate computations. Our initial investigation into the function invocations of serverless applications reveals an abundance of duplicate invocations. Inspired by this critical observation, we introduce HashCache , a system designed to cache duplicate function invocations, thereby mitigating duplicate computations. In HashCache, serverless functions are classified into three categories, namely, computational functions, stateful functions, and environment-related functions. On the grounds of such a function classification, HashCache associates the stateful functions and their states to build an adaptive synchronization mechanism. With this support, HashCache exploits the cached results of computational and stateful functions to serve upcoming invocation requests to the same functions, thereby reducing duplicate computations. Moreover, HashCache stores remote files probed by stateful functions into a local cache layer, which further curtails invocation latency. We implement HashCache within the Apache OpenWhisk to forge a cache-enabled serverless computing platform. We conduct extensive experiments to quantitatively evaluate the performance of HashCache in terms of invocation latency and resource utilization. We compare HashCache against two state-of-the-art approaches - FaaSCache and OpenWhisk . The experimental results unveil that our HashCache remarkably reduces invocation latency and resource overhead. More specifically, HashCache curbs the 99-tail latency of FaaSCache and OpenWhisk by up to 91.37% and 95.96% in real-world serverless applications. HashCache also slashes the resource utilization of FaaSCache and OpenWhisk by up to 31.62% and 35.51%, respectively.

Student-study behaviors and metacognition are predictors of student-academic success. However, student metacognitive evaluation of their own study habit behavior use has been largely unexplored. To address this gap, we gave students enrolled in three different Biology courses (n = 1140) a survey that asked them to identify the study behaviors used to prepare for their first and third exams and to appraise the effectiveness of each behavior. We observed that, across all courses, students used different counts of active- and passive-study behaviors. However, there were no differences in performance across courses, and the use of effective (i.e., active) study behaviors resulted in improved exam performance for all students, regardless of course, while the use of ineffective (i.e., passive) study behaviors had no significant impact on exam performance. Finally, our qualitative analysis revealed that students across all courses demonstrated similar ability in identifying effective-study behaviors, but students could not explain why those behaviors were effective. Taken together, our study demonstrates that students use various study behaviors to prepare for exams without understanding their effectiveness. We encourage instructors to structure their courses to promote the development of metacognitive evaluation and effective-study behaviors.

Garbage collection or GC running in the controller of 3-D NAND flash-based solid-state disks—SSDs—plays a critical role in the performance of storage systems. SSD manufacturers have developed various GC solutions based on internal data movement or IDM to mitigate the impacts of GC on request latency. Due to the circuit characteristics of flash memory, the existing IDM-based GC strategies are restricted by page parity during data movement: odd pages must be migrated to odd pages, and even pages to even pages. When migrating two consecutive pages with the same parity, the free page between the two migrated pages will be wasted after the migration is complete. This ever-increasing page waste problem inevitably deteriorates the storage space utilization of flash memory, thereby degrading the overall performance of 3-D NAND flash-based SSDs. To address this issue, we propose a parity-check GC scheme called PcGC to revamp SSD performance by alleviating page waste during GC. We build a parity-check unit in PcGC to facilitate checking the parity of migrated valid pages and destination pages. According to the parity results offered by the parity-check unit, PcGC dynamically adjusts the migration order of valid pages during the course of GC. In doing so, PcGC fundamentally averts page waste caused by the page parity restriction, thereby enhancing 3-D NAND flash performance. We quantitatively evaluate the performance of PcGC in terms of wasted pages, storage utilization, GC counts, write amplification, and average response time. We compare PcGC against the two state-of-the-art schemes—Amphibian and Tiny-tail flash (TTflash). The experimental results derived from the nine real-world workload traces unfold that compared with Amphibian and TTflash: 1) PcGC curtails the number of wasted pages by up to 91.4% with an average of 53.75%; 2) cuts back the number of GC counts by up to 52.2% with an average of 11.9%; and 3) slashes average write response time by up to 77.8% with an average of 13.0%.

Worldwide, significant efforts are made to identify energy sources that can help achieve carbon neutrality and promote sustainable development. The development of a catalyst that combines durability and high performance is essential for the commercialization of proton‐exchange membrane fuel cells (PEMFCs). In a fuel cell, carbon corrosion occurs during startup and shutdown due to improper local flooding caused by inadequate water management. In this study, a Pt‐based catalyst is designed with excellent durability and high activity. Introducing a metal oxide layer modified with Pt/multi‐walled carbon nanotubes reduces the direct contact between carbon and the fuel cell environment. This helps prevent carbon corrosion and inhibits the separation, aggregation, and growth of Pt nanoparticles. Moreover, the catalyst exhibits enhanced oxygen reduction activity due to the electronic effect of the metal oxide layer that is coated on it. In this study, by implementing a carbon erosion acceleration protocol, excellent catalytic properties during a load‐cycling experiment consisting of 5,000 cycles are reported. The practical application of the developed catalyst in PEMFCs offers an effective approach to developing Pt‐group metal catalysts with exceptional activity.

Plain Language Summary Electromagnetic ion cyclotron (EMIC) waves play an important role in the magnetospheric particle dynamics via wave‐particle interactions. Previous studies mainly focus on the resonance interaction between particles and EMIC waves. The resonance interaction is effective but it needs the energy of particles to be above the minimum resonant energy. In our observation, we find that the cold protons (∼eV) are energized up to suprathermal energies (∼tens of eV) by the EMIC waves, resulting in a series of bridge‐like arcs in the ion energy spectrogram. The energy of cold protons is much less than the minimum resonant energy, suggesting that the cold protons should be energized by the non‐resonance interaction. The polarization of EMIC waves could change the gyrophase distribution of bunched cold protons, but the energy transfer process is not affected by the polarization of EMIC waves. The observations suggest EMIC waves can affect the magnetospheric particle dynamics by energizing the cold protons.

Type VI secretion system (T6SS) is a versatile, contact-dependent contractile nano-weapon in Gram-negative bacteria that fires proteinaceous effector molecules directly into prokaryotic and eukaryotic cells aiding in manipulation of the host and killing of competitors in complex niches. In plant pathogenic xanthomonads, T6SS has been demonstrated to play these diverse roles in individual pathosystems. However, the molecular network underlying the regulation of T6SS is still elusive in Xanthomonas spp. To bridge this knowledge gap, we conducted an in vitro transcriptome screen using plant apoplast mimicking minimal medium, XVM2 medium, to decipher the effect of tssM deletion, a core gene belonging to T6SS-cluster i3*, on the regulation of gene expression in Xanthomonas perforans strain AL65. Transcriptomic data revealed that a total of 277 and 525 genes were upregulated, while 307 and 392 genes were downregulated in the mutant strain after 8 and 16 hours of growth in XVM2 medium. The transcript abundance of several genes associated with flagellum and pilus biogenesis as well as type III secretion system was downregulated in the mutant strain. Deletion of tssM of cluster-i3* resulted in upregulation of several T6SS genes belonging to cluster-i3*** and genes involved in biofilm and cell wall biogenesis. Similarly, transcription regulators like rpoN , Pho regulon, rpoE , and csrA were identified to be upregulated in the mutant strain. Our results suggest that T6SS modulates the expression of global regulators like csrA , rpoN , and pho regulons, triggering a signaling cascade, and co-ordinates the expression of suite of virulence factors, stress response genes, and metabolic genes. IMPORTANCE T6SS has received attention due to its significance in mediating interorganismal competition through contact-dependent release of effector molecules into prokaryotic and eukaryotic cells. Reverse-genetic studies have indicated the role of T6SS in virulence in a variety of plant pathogenic bacteria, including the one studied here, Xanthomonas . However, it is not clear whether such effect on virulence is merely due to a shift in the microbiome-mediated protection or if T6SS is involved in a complex virulence regulatory network. In this study, we conducted in vitro transcriptome profiling in minimal medium to decipher the signaling pathways regulated by tssM-i3* in X. perforans AL65. We show that TssM-i3* regulates the expression of a suite of genes associated with virulence and metabolism either directly or indirectly by altering the transcription of several regulators. These findings further expand our knowledge on the intricate molecular circuits regulated by T6SS in phytopathogenic bacteria.

The Vetscan Imagyst system (Zoetis) is a novel, artificial intelligence–driven detection tool that can assist veterinarians in the identification of enteric parasites in dogs and cats. This system consists of a sample preparation device, an automated digital microscope scanner, and a deep-learning algorithm. The EasyScan One scanner (Motic) has had good diagnostic performance compared with manual examinations by experts; however, there are drawbacks when used in veterinary practices in which space for equipment is often limited. To improve the usability of this system, we evaluated an additional scanner, the Ocus 40 (Grundium). Our objectives were to 1) qualitatively evaluate the performance of the Vetscan Imagyst system with the Ocus 40 scanner for identifying Ancylostoma, Toxocara, and Trichuris eggs, Cystoisospora oocysts, and Giardia cysts in canine and feline fecal samples, and 2) expand the assessment of the performance of the Vetscan Imagyst system paired with either the Ocus 40 or EasyScan One scanner to include a larger dataset of 2,191 fecal samples obtained from 4 geographic regions of the United States. When tested with 852 canine and feline fecal samples collected from different geographic regions, the performance of the Vetscan Imagyst system combined with the Ocus 40 scanner was correlated closely with manual evaluations by experts. Sensitivities were 80.0‒97.0% and specificities were 93.7‒100.0% across the targeted parasites. When tested with 1,339 fecal samples, the Vetscan Imagyst system paired with the EasyScan One scanner successfully identified the targeted parasite stages; sensitivities were 73.6‒96.4% and specificities were 79.7‒100.0%.