Eight carbonaceous fractions from aerosols were resolved using the Interagency Monitoring of Protected Visual Environments (IMPROVE) protocol (Chow et al., 1993). The aerosols were collected at the ...Mountain Lulin Atmospheric Background Station (Mt. Lulin, 2862 m a.s.l.) in Central Taiwan from April 2003 to April 2012. The monthly and yearly levels of organic carbon (OC) and elemental carbon (EC) varied consistently with PM2.5 mass concentrations during biomass burning (BB) period. The highest monthly carbonaceous content was observed in March and the highest yearly carbonaceous concentration was observed in 2007. This finding is consistent with the BB activity in Indochina and indicates that carbonaceous content is a major component of BB aerosols. Lee et al. (2011) classified four trajectory groups from the air masses transported to Mt. Lulin during the aerosol collection period. For the air masses transported from the BB area (the BB group) in Indochina, the carbonaceous content was greater than the water-soluble ions in PM2.5, and the OC/EC ratio (4.8 ± 1.5) was high. With EC as the indicator of primary emission sources, the air masses of the BB group were found to contain more primary than secondary OC. The Anthropogenic group (from the local and free troposphere below the 700-hPa pressure level over the Asian continent) probably contained more secondary than primary OC or the sources of OC and EC could be quite diverse. The average char-EC/soot-EC (low-temperature EC/high-temperature EC) ratios were 3.9 ± 3.5, 0.4 ± 0.4, 0.9 ± 0.8, and 0.3 ± 0.4 for the trajectory groups BB, SNBB (from BB source areas during the non-BB period), Anthropogenic, and FT (from the oceanic area and the free troposphere above the 700-hPa pressure level over the Asian continent), respectively. The presence of a high char-EC/soot-EC ratio confirmed the correct classification of the BB group, whereas the low ratios from the other groups indicated the strong influence of vehicle exhaust. It is noted that higher OC and EC levels were obtained at Mt. Lulin as compared with those obtained at other high-elevation sites. This difference suggested that the Indochina BB plume exhibited a more serious climatic impact on the background air in East Asia than in other places in Asia and Europe. On the basis of the carbonaceous levels of the SNBB and FT groups, the background OC and EC levels of approximately 3000 m in the West Pacific are around 1.33 μg m−3 and 0.35 μg m−3, respectively.
•Long-term observation of carbonaceous aerosols in East Asia.•Transported Indochina biomass burning plume is observed at Mt. Lulin.•Aerosol carbonaceous content is enhanced in biomass burning plume.•The impact of Indochina biomass burning is more serious than other places.•The West Pacific background OC and EC are 1.33 μg m−3 and 0.35 μg m−3.
Plastic crystal neopentylglycol (NPG) exhibits colossal barocaloric effects (BCEs) with record-high entropy changes, offering exciting prospects for the field of solid-state cooling through the ...application of moderate pressures. Here, we show that the intermolecular hydrogen bond plays a key role in the orientational order of NPG molecules, while its broken due to thermal perturbation prominently weakens the activation barrier of orientational disorder. The analysis of hydrogen bond strength, rotational entropy free energy and entropy changes provides insightful understanding of BCEs in order-disorder transition. External pressure reduce the hydsrogen bond length and enhance the activation barrier of orientational disorder, which serves as a route of varying intermolecular interaction to tune the order-disorder transition. Our work provides atomic-scale insights on the orientational order-disorder transition of NPG as the prototypical plastic crystal with BCEs, which is helpful to achieve superior caloric materials by molecular designing in the near future.
Biomass burning (BB) in Indochina produces a great amount of aerosols, but related information on this phenomenon is scarce. In the present study, aerosol samples were collected from Suthep Mountain ...(98° 53′E, 18° 48′N, 1396 m) in Chiangmai, Northern Indochina, in March and April 2010. To our knowledge, this study is the first to reveal the chemical characteristics of BB aerosol near the burning sources in Indochina. The composition analyzed included water-soluble ions, carbonaceous fractions obtained using the thermal optical reflectance method, low-molecular-weight dicarboxylates, anhydrosugars, and water-soluble organic carbon (WSOC). Enriched tracers from the collected aerosols, such as potassium ion (K+) and levoglucosan, confirmed that the samples were influenced by BB activity. The percentage of K+ in PM2.5 (2.51% ± 0.31%) in the present study is higher than that in other studies. The analysis also showed that directly emitted organic carbon (OC) is the most abundant component in the collected particles. The percentage of WSOC in OC in the present study is greater than that in laboratory experiments. Moreover, the char-EC to soot-EC ratio (defined as the ratio of the subtraction of pyrolized OC from the measured EC1, EC1-OP, over the sum of EC2 and EC3) of 9.4 ± 3.8 in PM2.5 is similar to the value of BB in the literature. Using the recognized BB aerosol tracers K+ and levoglucosan, the present study inferred that PM2.5 EC1-OP and OC3 are also good BB tracers near sources. The collected BB aerosols may have been contributed by the smoldering state of softwood burning.
► The first aerosol characterization for near-source biomass burning in Indochina. ► Organic carbon is the most abundant aerosol component. ► The percentage of K+ in PM2.5 is higher than in other ambient studies. ► PM2.5 K+, levoglucosan, EC1-OP, and OC3 are good BB tracers near sources. ► The collected aerosol was inferred from the smoldering state of softwood burning.
This paper investigates active localization of a stationary object using time delay alone or together with Doppler shift measurements observed by a number of dynamic monostatic sensors having ...collocated transmitters and receivers, where the sensor motion during the interrogation period is not negligible. Non-negligible motion effect appears when the sensor speed relative to the signal propagation speed is significant, such as in an acoustic or an underwater environment. The motion effect causes the signal sent and received locations different, with their separation proportional to the two-way propagation time delay that is dependent on the object location. We first provide new measurement models for time delay and Doppler shift in the presence of sensor motion. They come as recursive equations and their non-recursive forms are derived. Analysis of the motion effect based on the Cramér-Rao lower bound (CRLB) is conducted, and the performance loss in terms of the location bias and variance when ignoring the sensor motion effect is evaluated. Two kinds of estimators for the object location are next proposed by exploiting the non-recursive forms of the model equations. One is a closed-form solution by algebraic evaluation and the other is a semi-definite relaxation solution by convex optimization. The first is computationally efficient and is shown to achieve the CRLB performance over the small error region under Gaussian noise, while the second can handle the positioning problem better when the noise level is high. Simulations validate the theoretical analysis and the performance of the proposed estimators.
Abstract Anhedonia is a hallmark symptom of major depressive disorder (MDD). Preliminary findings suggest that anhedonia is characterized by reduced reward anticipation and motivation of obtaining ...reward. However, relatively little is known about reward-based decision-making in depression. We tested the hypothesis that anhedonia in MDD may reflect specific impairments in motivation on reward-based decision-making and the deficits might be associated with depressive symptoms severity. In study 1, individuals with and without depressive symptoms performed the modified version of the Effort Expenditure for Rewards Task (EEfRT), a behavioral measure of cost/benefit decision-making. In study 2, MDD patients, remitted MDD patients and healthy controls were recruited for the same procedures. We found evidence for decreased willingness to make effort for rewards among individuals with subsyndromal depression; the effect was amplified in MDD patients, but dissipated in patients with remitted depression. We also found that reduced anticipatory and consummatory pleasure predicted decreased willingness to expend efforts to obtain rewards in MDD patients. For individuals with subsyndromal depression, the impairments were correlated with anticipatory anhedonia but not consummatory anhedonia. These data offer novel evidence that motivational deficits in MDD are correlated with depression severity and predicted by self-reported anhedonia.
Schizotypy, a subclinical group at risk for schizophrenia, has been found to show impairments in response inhibition. However, it remains unclear whether this impairment is accompanied by outright ...stopping (reactive inhibition) or preparation for stopping (proactive inhibition). We recruited 20 schizotypy and 24 non-schizotypy individuals to perform a modified stop-signal task with electroencephalographic (EEG) data recorded. This task consists of three conditions based on the probability of stop signal: 0% (no stop trials, only go trials), 17% (17% stop trials), and 33% (33% stop trials), the conditions were indicated by the colour of go stimuli. For proactive inhibition (go trials), individuals with schizotypy exhibited significantly lesser increase in go response time (RT) as the stop signal probability increasing compared to non-schizotypy individuals. Individuals with schizotypy also exhibited significantly increased N1 amplitude on all levels of stop signal probability and increased P3 amplitude in the 17% stop condition compared with non-schizotypy individuals. For reactive inhibition (stop trials), individuals with schizotypy exhibited significantly longer stop signal reaction time (SSRT) in both 17% and 33% stop conditions and smaller N2 amplitude on stop trials in the 17% stop condition than non-schizotypy individuals. These findings suggest that individuals with schizotypy were impaired in both proactive and reactive response inhibition at behavioural and neural levels.
This paper investigates the problem of active localization of a moving object in its initial position and velocity, using time delay only or with Doppler shift measurements acquired by a number of ...monostatic sensors. Each sensor has non-negligible motion during the observation period, causing it at different positions when it sends and receives the signal, with the separation proportional to the signal travel time in reaching the object and returning back. The object is not at the same position when it reflects the signals from various sensors due to its motion. Both motion effects lead to recursive model equations for time delay and Doppler shift, making the localization problem interesting and challenging. We shall derive the measurement model equations under this scenario, evaluate the Cramer-Rao lower bound (CRLB) of the estimation problem and analyze the proposed models by contrasting with the performance loss when ignoring the object and sensor motion effects. The Maximum Likelihood Estimators (MLEs) are next developed, using the Gauss-Newton or Quasi-Newton iterations. Algebraic solution for the special case of moving object non-moving sensors is derived and analyzed, and it can serve as an effective initialization of the iterative MLEs if sensor motion is present. Both the theoretical analysis and simulation studies corroborate the importance of taking the object and sensor motions into consideration during the observation period, when the relative velocity between the object and sensor is significant compared to the signal propagation speed, such as in an acoustic or underwater environment.
Inflammation contributes to the tubulointerstitial lesions of diabetic nephropathy. Toll-like receptors (TLRs) modulate immune responses and inflammatory diseases, but their role in diabetic ...nephropathy is not well understood. In this study, we found increased expression of TLR4 but not of TLR2 in the renal tubules of human kidneys with diabetic nephropathy compared with expression of TLR4 and TLR2 in normal kidney and in kidney disease from other causes. The intensity of tubular TLR4 expression correlated directly with interstitial macrophage infiltration and hemoglobin A1c level and inversely with estimated glomerular filtration rate. The tubules also upregulated the endogenous TLR4 ligand high-mobility group box 1 in diabetic nephropathy. In vitro, high glucose induced TLR4 expression via protein kinase C activation in a time- and dose-dependent manner, resulting in upregulation of IL-6 and chemokine (C-C motif) ligand 2 (CCL-2) expression via IκB/NF-κB activation in human proximal tubular epithelial cells. Silencing of TLR4 with small interfering RNA attenuated high glucose-induced IκB/NF-κB activation, inhibited the downstream synthesis of IL-6 and CCL-2, and impaired the ability of conditioned media from high glucose-treated proximal tubule cells to induce transmigration of mononuclear cells. We observed similar effects using a TLR4-neutralizing antibody. Finally, streptozotocin-induced diabetic and uninephrectomized TLR4-deficient mice had significantly less albuminuria, renal dysfunction, renal cortical NF-κB activation, tubular CCL-2 expression, and interstitial macrophage infiltration than wild-type animals. Taken together, these data suggest that a TLR4-mediated pathway may promote tubulointerstitial inflammation in diabetic nephropathy.
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