156 research outputs found
Integrating Sensing, Communication, and Power Transfer: Multiuser Beamforming Design
In the sixth-generation (6G) networks, massive low-power devices are expected
to sense environment and deliver tremendous data. To enhance the radio resource
efficiency, the integrated sensing and communication (ISAC) technique exploits
the sensing and communication functionalities of signals, while the
simultaneous wireless information and power transfer (SWIPT) techniques
utilizes the same signals as the carriers for both information and power
delivery. The further combination of ISAC and SWIPT leads to the advanced
technology namely integrated sensing, communication, and power transfer
(ISCPT). In this paper, a multi-user multiple-input multiple-output (MIMO)
ISCPT system is considered, where a base station equipped with multiple
antennas transmits messages to multiple information receivers (IRs), transfers
power to multiple energy receivers (ERs), and senses a target simultaneously.
The sensing target can be regarded as a point or an extended surface. When the
locations of IRs and ERs are separated, the MIMO beamforming designs are
optimized to improve the sensing performance while meeting the communication
and power transfer requirements. The resultant non-convex optimization problems
are solved based on a series of techniques including Schur complement
transformation and rank reduction. Moreover, when the IRs and ERs are
co-located, the power splitting factors are jointly optimized together with the
beamformers to balance the performance of communication and power transfer. To
better understand the performance of ISCPT, the target positioning problem is
further investigated. Simulations are conducted to verify the effectiveness of
our proposed designs, which also reveal a performance tradeoff among sensing,
communication, and power transfer.Comment: This paper has been submitted to IEEE for possible publicatio
Seasonality is more important than forest type in regulating the pool size and composition of soil soluble N in temperate forests
How do tree species with different successional stages affect soil organic nitrogen transformations?
Organic nitrogen (N) is the most important N component of soil organic matter.However, knowledge on how tree species with different successional stages affect its transformations in soils remains limited. To address this issue, we sampled mineral soils (0−10 cm) in monocultures composed by tree species of different successional stages, including early (black alder and silver birch), early to mid (sycamore and European ash), and late (sweet chestnut, pedunculate oak and European beech), and measured the potential protease activity, the microbial uptake and respiration of 14C-labeled organic N (L-alanine and L-trialanine), and the mineralization of L-alanine N. The activities of alanine aminopeptidase and leucine aminopeptidase (153.8−341.9 and 91.6−147.9 nmol/g/h, respectively), the half-life of the uptake of alanine and trialanine (26.7−39.6 and 60.8−78.6 min, respectively), the half-life of the mineraliztion of alanine and trialanine (1.98−2.45 and 2.98−4.13 h, respectively) by soil microbes were altered by tree species of different successional stages, systematically changing the transformation chain of soil organic N. From trees of early successional stage to that of late, the turnover rates of soil organic N appeared to decrease and the half-life appeared to increase significantly. The (carbon) C:N ratio of soil microbial biomass was positively related to the half-life of 14Clabeled alanine and trialanine mineralization, and was negatively related to the C use efficiency of alanine, suggesting that microbial demand for C could partially drive the assimilation of soil organic N. Our results suggest that the successional stage of tree species play an important role in regulating the soil organic N turnover. An improved understanding of how tree species with different successional stages influence microbial function and soil organic N cycling is beneficial to future afforestation and forest management, alleviating the impacts of global change on the ecosystem
Sensitivity of Mesoscale Modeling of Smoke Direct Radiative Effect to the Emission Inventory: a Case Study in Northern Sub-Saharan African Region
An ensemble approach is used to examine the sensitivity of smoke loading and smoke direct radiative effect in the atmosphere to uncertainties in smoke emission estimates. Seven different fire emission inventories are applied independently to WRF-Chem model (v3.5) with the same model configuration (excluding dust and other emission sources) over the northern sub-Saharan African (NSSA) biomass-burning region. Results for November and February 2010 are analyzed, respectively representing the start and end of the biomass burning season in the study region. For February 2010, estimates of total smoke emission vary by a factor of 12, but only differences by factors of 7 or less are found in the simulated regional (15degW-42degE, 13degS-17degN) and monthly averages of column PM(sub 2.5) loading, surface PM(sub 2.5) concentration, aerosol optical depth (AOD), smoke radiative forcing at the top-of-atmosphere and at the surface, and air temperature at 2 m and at 700 hPa. The smaller differences in these simulated variables may reflect the atmospheric diffusion and deposition effects to dampen the large difference in smoke emissions that are highly concentrated in areas much smaller than the regional domain of the study. Indeed, at the local scale, large differences (up to a factor of 33) persist in simulated smoke-related variables and radiative effects including semi-direct effect. Similar results are also found for November 2010, despite differences in meteorology and fire activity. Hence, biomass burning emission uncertainties have a large influence on the reliability of model simulations of atmospheric aerosol loading, transport, and radiative impacts, and this influence is largest at local and hourly-to-daily scales. Accurate quantification of smoke effects on regional climate and air quality requires further reduction of emission uncertainties, particularly for regions of high fire concentrations such as NSSA
Sensitivity of Mesoscale Modeling of Smoke Direct Radiative Effect to the Emission Inventory: A Case Study in Northern Sub-Saharan African Region
An ensemble approach is used to examine the sensitivity of smoke loading and smoke direct radiative effect in the atmosphere to uncertainties in smoke emission estimates. Seven different fire emission inventories are applied independently to WRF-Chem model (v3.5) with the same model configuration (excluding dust and other emission sources) over the northern sub-Saharan African (NSSA) biomass-burning region. Results for November and February 2010 are analyzed, respectively representing the start and end of the biomass burning season in the study region. For February 2010, estimates of total smoke emission vary by a factor of 12, but only differences by factors of 7 or less are found in the simulated regional (15°W–42°E, 13°S–17°N) and monthly averages of column PM2.5 loading, surface PM2.5 concentration, aerosol optical depth (AOD), smoke radiative forcing at the top-of-atmosphere and at the surface, and air temperature at 2 m and at 700 hPa. The smaller differences in these simulated variables may reflect the atmospheric diffusion and deposition effects to dampen the large difference in smoke emissions that are highly concentrated in areas much smaller than the regional domain of the study. Indeed, at the local scale, large differences (up to a factor of 33) persist in simulated smoke-related variables and radiative effects including semi-direct effect. Similar results are also found for November 2010, despite differences in meteorology and fire activity. Hence, biomass burning emission uncertainties have a large influence on the reliability of model simulations of atmospheric aerosol loading, transport, and radiative impacts, and this influence is largest at local and hourly-to-daily scales. Accurate quantification of smoke effects on regional climate and air quality requires further reduction of emission uncertainties, particularly for regions of high fire concentrations such as NSSA
Risk factors and the value of microbiological examinations of COVID-19 associated pulmonary aspergillosis in critically ill patients in intensive care unit: the appropriate microbiological examinations are crucial for the timely diagnosis of CAPA
IntroductionDuring the Omicron pandemic in China, a significant proportion of patients with Coronavirus Disease 2019 (COVID-19) associated pulmonary aspergillosis (CAPA) necessitated admission to intensive care unit (ICU) and experienced a high mortality. To explore the clinical risk factors and the application/indication of microbiological examinations of CAPA in ICU for timely diagnosis are very important.MethodsThis prospective study included patients with COVID-19 admitted to ICU between December 1, 2022, and February 28, 2023. The clinical data of influenza-associated pulmonary aspergillosis (IAPA) patients from the past five consecutive influenza seasons (November 1, 2017, to March 31, 2022) were collected for comparison. The types of specimens and methods used for microbiological examinations were also recorded to explore the efficacy in early diagnosis.ResultsAmong 123 COVID-19 patients, 36 (29.3%) were diagnosed with probable CAPA. CAPA patients were more immunosuppressed, in more serious condition, required more advanced respiratory support and had more other organ comorbidities. Solid organ transplantation, APACHEII score ≥20 points, 5 points ≤SOFA score <10 points were independent risk factors for CAPA. Qualified lower respiratory tract specimens were obtained from all patients, and 84/123 (68.3%) patients underwent bronchoscopy to obtain bronchoalveolar lavage fluid (BALF) specimens. All patients’ lower respiratory tract specimens underwent fungal smear and culture; 79/123 (64.2%) and 69/123 (56.1%) patients underwent BALF galactomannan (GM) and serum GM detection, respectively; metagenomic next-generation sequencing (mNGS) of the BALF was performed in 62/123 (50.4%) patients. BALF GM had the highest diagnostic sensitivity (84.9%), the area under the curve of the mNGS were the highest (0.812).ConclusionThe incidence of CAPA was extremely high in patients admitted to the ICU. CAPA diagnosis mainly depends on microbiological evidence owing to non-specific clinical manifestations, routine laboratory examinations, and CT findings. The bronchoscopy should be performed and the BALF should be obtained as soon as possible. BALF GM are the most suitable microbiological examinations for the diagnosis of CAPA. Due to the timely and accuracy result of mNGS, it could assist in early diagnosis and might be an option in critically ill CAPA patients
Enabling the ability of Li storage at high rate as anodes by utilizing natural rice husks-based hierarchically porous SiO2/N-doped carbon composites
One of the greatest challenges in developing SiO 2/C composites as anode materials in lithium ion batteries (LIBs) is to improve the ability of Li storage at high rate over long-term cycles. Herein, biomass rice husks-based hierarchically porous SiO 2/N-doped carbon composites (BM-RH-SiO 2/NC) were prepared by ball mill and thermal treatment. BM-RH-SiO 2/NC can still retain a reversible capacity of 556 mAh g −1 over 1000 cycles at a high current of 1.0 A g −1. At 5.0 A g −1 the capacity is kept as high as 402 mAh g −1. This impressively long-term cyclic performance and high-rate capability of BM-RH-SiO 2/NC can be ascribed to the synergetic effect between the natural SiO 2 nanoparticles (< 50 nm) and the NC layer. The coating NC layer can not only effectively mitigate the volume strain during charge-discharge process to offer stably cyclic performance but also improve the electrical conductivity. Furthermore, the hierarchical porosity and better electrolyte wettability offer the rapid Li + diffusion and electron transfer, which enhance the pseudocapacitive behavior of whole electrode material and then guarantee fast electrochemical kinetics. Importantly, the unique Li-storage mechanism of active SiO 2 in BM-RH-SiO 2/NC composite was formed and found, which further validates the improved electrochemical capability
SapC-DOPS nanovesicles induce Smac- and Bax-dependent apoptosis through mitochondrial activation in neuroblastomas
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