The global extent and distribution of forest trees is central to our understanding of the terrestrial biosphere. We provide the first spatially continuous map of forest tree density at a global ...scale. This map reveals that the global number of trees is approximately 3.04 trillion, an order of magnitude higher than the previous estimate. Of these trees, approximately 1.39 trillion exist in tropical and subtropical forests, with 0.74 trillion in boreal regions and 0.61 trillion in temperate regions. Biome-level trends in tree density demonstrate the importance of climate and topography in controlling local tree densities at finer scales, as well as the overwhelming effect of humans across most of the world. Based on our projected tree densities, we estimate that over 15 billion trees are cut down each year, and the global number of trees has fallen by approximately 46% since the start of human civilization.
Consequent-pole permanent magnet (CPM) machines have considerable potential for low-cost applications because they can improve the permanent magnet (PM) utilization ratio. However, the phase back ...electromotive force (EMF) of CPM machines with N s /( mt ) = odd ( t is the greatest common divisor of the stator slot number N s and the rotor pole-pair number p , and m is the phase number) is asymmetric, i.e., the phase back EMF has even-order harmonics, which will increase torque ripples. This paper utilized the staggered rotor to eliminate the even-order harmonics and reduce the cogging torque of CPM machines, thereby potentially decreasing torque ripples considerably. The axial flux barrier in the middle of the rotor was used and optimized using three-dimensional finite element (FE) analysis to reduce the axial leakage flux of the CPM machine with the proposed staggered rotor. Furthermore, the axial magnetized PM was embedded in the flux barrier, which improved the flux density of the airgap above the iron-pole and, consequently, further increased the output torque. The electromagnetic performance of the proposed machine, including the open-circuit airgap flux density, back EMF, average torque, torque ripples, and PM utilization, was compared with that of the conventional CPM machine. Results showed that the proposed machine obtained a similar torque and PM utilization ratio but a much lower torque ripple compared with the conventional one.
Patients with severe chronic obstructive pulmonary disease (COPD) are at higher risk of developing invasive pulmonary aspergillosis (IPA). However, there are limited data for this disease. To ...evaluate risk factors and the clinical characteristics of IPA in COPD patients, we conducted a hospital-based, retrospective case-control study of 30 COPD patients with IPA and 60 COPD control patients without IPA. Patients in the case group were significantly more likely to have concurrent co-morbidities than controls. Of the IPA patients, 65.4% had worsening radiological findings vs. 11.4% in the control group (p <0.001). IPA in COPD was associated with a higher proportion of mechanical ventilation (43.3% vs. 5%; p <0.001), a longer hospital stay duration (45.8 ± 39.1 days vs. 18.4 ± 11.8 days; p <0.001), and higher mortality (43.3% vs. 11.4%; p <0.001). Systemic use of steroids in the stable phase, treatment with three or more antibiotics during hospitalization and antibiotic treatment longer than 10 days were independent risk factors associated with IPA. COPD patients with obvious dyspnoea, antibiotic-resistant lower respiratory tract infection and repeated detection of Aspergillus in sputum should be considered for the possibility of IPA.
To provide an observational basis for the Intergovernmental Panel on Climate Change projections of a slowing Atlantic meridional overturning circulation (MOC) in the 21st century, the Overturning in ...the Subpolar North Atlantic Program (OSNAP) observing system was launched in the summer of 2014. The first 21-month record reveals a highly variable overturning circulation responsible for the majority of the heat and freshwater transport across the OSNAP line. In a departure from the prevailing view that changes in deep water formation in the Labrador Sea dominate MOC variability, these results suggest that the conversion of warm, salty, shallow Atlantic waters into colder, fresher, deep waters that move southward in the Irminger and Iceland basins is largely responsible for overturning and its variability in the subpolar basin.
An AA6082 alloy deformed by equal channel angular pressing (ECAP) was studied. Microstructural evolution of the alloy processed by ECAP with different passes were evaluated by using optical ...microscope, scanning electron microscopy coupled with an electron backscattered diffraction (EBSD) detector and X-ray diffraction. Texture analysis showed the apparition of two types of textures, one associated with shearing deformation and the second due to the recrystallization phenomena. Mechanical strength properties measured by tensile tests increased in the first ECAP pass, and then progressively diminished due to the presence of concurrent softening phenomena. Calorimetric analysis indicated a slightly increase in the recrystallization temperature of the deformed specimens. Also, the stored energy increased with increasing ECAP passes due to the production of new dislocations. The average geometrically necessary dislocation density, measured by EBSD, increased with increasing ECAP passes. However, the rate of increase slows down with the progress of ECAP passes.
Graphic Abstract
AIMS: The influence of bacterial species/strains in agitated culture was investigated on the morphology and structure characteristics of bacterial cellulose. METHODS AND RESULTS: Komagataeibacter ...nataicola Y19 and Gluconacetobacter entanii ACCC10215 were inoculated in Hestrin–Schramm (HS) medium and subjected to agitated cultivation. Different kinds of BCs were obtained including flocky asterisk‐like BC by G. entanii ACCC10215 and solid sphere‐like BC by K. nataicola Y19. The SEM results showed that the asterisk‐like BC had larger pores than the solid sphere‐like BC. The FT‐IR and X‐ray diffraction results showed the asterisk‐like BC had lower crystallinity (81·43%), higher cellulose Iα mass fraction (79·74%) and smaller crystallite size. CONCLUSIONS: The different species/strains can influence the morphology and structure characteristics of BC in agitated culture. SIGNIFICANCE AND IMPACT OF THE STUDY: We examined the influence of different species/strains on the morphology, macro‐ and microstructure of BCs produced in agitated culture for the first time, which suggest that different BCs with potential applications could be obtained by choosing different species or strains and fermentation method.
Tuberculosis (TB) is the leading cause of death among people living with HIV/AIDS (PLWHA), posing a significant disease burden. Early TB screening in PLWHA is a key intervention to reduce ...transmission and control disease progression. Lipoarabinomannan (LAM) is a glycolipid of
(MTB) that can be detected in the urine of tuberculosis patients. LAM is useful for the rapid and accurate diagnosis of tuberculosis. This article reviews LAM and its application and limitations in the diagnosis of PLWHA, hoping to provide a reference for the diagnosis of tuberculosis in PLWHA.
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