•We identified a previously unknown ∼2.9 Ga magmatic event in Eastern Hebei, which may challenges the long-held view that granitic gneisses in Eastern Hebei Province, though diverse in composition, ...type and origin, were emplaced and crystallized in a rather short period of magmatic activity.
We report the results of a comprehensive isotopic investigation of zircons from metamorphosed orthogneisses from Caochang village in the Zunhua Complex, Eastern Hebei, North China Craton (NCC). A detailed investigation of the internal structures of these zircons combined with SIMS U–Pb and ICP-MS Lu-Hf zircon analyses, as well as a whole-rock geochemical study, revealed a previously unknown ∼2.9 Ga magmatic event in Eastern Hebei. The identified Mesoarchean gneisses are mainly felsic gneisses and amphibolites. Amphibolites with positive εNd(t) values were derived from the depleted mantle, with some crustal contamination during ascent. Zircon Hf isotopes indicate that the high-silica gneisses originate from the high-temperature mixing of mafic magma derived from a depleted mantle source and the subsequent felsic magma derived from the melting of ancient crustal materials, with the subsequent high degree fractional crystallization of the parental magma. Some of the 2.9 Ga felsic gneisses may record an anatectic event at 2.5 Ga. The widespread ancient inherited and detrital zircons (>2.6 Ga) and the existence of Mesoarchean rocks imply a possible ancient continent in Eastern Hebei. It may also imply that the Mesoarchean era (especially at 2.9 Ga) represents another important magmatic event in the eastern block of the NCC. The identification of 2.9 Ga rocks indicates that the magmatic history of Eastern Hebei is far more complex than previously thought.
With the rising of e-hailing services in urban areas, ride sharing is becoming a common mode of transportation. This paper presents a mathematical model to design an enhanced ridesharing system with ...meet points and users' preferable time windows. The introduction of meet points allows ridesharing operators to trade off the benefits of saving en-route delays and the cost of additional walking for some passengers to be collectively picked up or dropped off. This extension to the traditional door-to-door ridesharing problem brings more operation flexibility in urban areas (where potential requests may be densely distributed in neighborhood), and thus could achieve better system performance in terms of reducing the total travel time and increasing the served passengers. We design and implement a Tabu-based meta-heuristic algorithm to solve the proposed mixed integer linear program (MILP). To evaluate the validation and effectiveness of the proposed model and solution algorithm, several scenarios are designed and also resolved to optimality by CPLEX. Results demonstrate that (i) detailed route plan associated with passenger assignment to meet points can be obtained with en-route delay savings; (ii) as compared to CPLEX, the meta-heuristic algorithm bears the advantage of higher computation efficiency and produces good quality solutions with 8%~15% difference from the global optima; and (iii) introducing meet points to ridesharing system saves the total travel time by 2.7%-3.8% for small-scale ridesharing systems. More benefits are expected for ridesharing systems with large size of fleet. This study provides a new tool to efficiently operate the ridesharing system, particularly when the ride sharing vehicles are in short supply during peak hours. Traffic congestion mitigation will also be expected.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Parkinson's disease (PD) is recognized as a degenerative and debilitating neurodegenerative disorder. The novel protective role of icariside II (ICS II) as a plant-derived flavonoid compound in ...neurodegenerative diseases has aroused much attention. Herein, the definite impacts of ICS II on the process of PD and the relevant action mechanism were studied. Human neuroblastoma SK-N-SH cells were challenged with 1-methyl-4-phenylpyridinium ion (MPP
) to construct the PD cell model. MTT assay and flow cytometry analysis, respectively, appraised cell viability and apoptosis. Caspase 3 Activity Assay examined caspase 3 activity. Corresponding kits examined oxidative stress levels. BODIPY 581/591 C11 assay evaluated lipid reactive oxygen species. Iron Assay Kit assessed iron content. Western blot tested the expression of apoptosis-, ferroptosis- and Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2)/glutathione peroxidase 4 (GPX4) signaling-associated proteins. Molecular docking verified the binding of ICS II with Keap1. The existing experimental results unveiled that ICS II elevated the viability whereas reduced the apoptosis, oxidative stress, and ferroptosis in MPP
-treated SK-N-SH cells in a concentration-dependent manner. Furthermore, ICS II declined Keap1 expression while raised Nrf2, heme oxygenase 1, and GPX4 expression. In addition, ICS II had a strong binding with Keap1 and Nrf2 inhibitor ML385 partially abolished the suppressive role of ICS II in MPP
-triggered apoptosis, oxidative stress, and ferroptosis in SK-N-SH cells. To summarize, ICS II might inhibit apoptosis, oxidative stress, and ferroptosis in the MPP
-stimulated PD cell model, which might be due to the activation of Keap1/Nrf2/GPX4 signaling.
Zircons with core-rim structure are common in granitoids worldwide. Mostly, the cores have strikingly older ages than the rims. Whether the zircon cores are inherited from the source of the ...granitoids or just occasionally captured from the wallrocks during magma ascent is highly controversial. In this paper, three Mesozoic granites with diverse ages and geochemical compositions but uniformly ~1.8 Ga zircon cores are reported from the Fengning area of North China Craton. The zircon cores in the Bingshanliang I-type granites have much higher δ18O values (8.3‰ to 10.1‰) than the magmatic zircons, strongly arguing against that these zircon cores are from the source of the granites. Instead, they could come from the wallrock during magma ascent. This conclusion is consistent with the occurrence of ~1.8 Ga S-type granites and meta-sedimentary rocks in the region which are characterized by high δ18O values. Similarly, zircon cores in the Wudaoying and Niuquanziba granites share many similarities in trace elements with the widely outcropped ~1.8 Ga granitoids, suggesting their probably xenocrystic origin from the Paleoproterozoic granitoids. The xenocrystic speculation is further supported by the lack of obviously modified internal textures and trace element imprints in the ~1.8 Ga zircon cores due to the effect of the Mesozoic anatexis if they had been derived from the source region of the granites. Combined with the bulk rock Nd isotopic and magmatic zircon Hf isotopic compositions, the three Mesozoic granites are suggested to be derived from the late Archean lower crust. It is inferred that ~2.5 zircon cores in some Mesozoic granitoids from other parts of the North China Craton are also likely captured grains from the wallrock during magma intrusion into the ~2.5 Ga basement rocks, rather than from the source. The magmatic zircon trace elements from the Wudaoying and Niuquanziba granites fingerprint the adakitic and A-type characters of their respective magma, implying their utility in tracing granites' derivation.
•Prevailing ~1.8 Ga zircon cores were identified in Mesozoic granites in Fengning area.•Oxygen and trace element analyses support their xenocrystic but inherited origin.•The rocks were derived from late Archean crustal rocks, similar to other granites.•Zircon cores and trace elements are useful in deciphering granite's provenance.
•Archean magmatic events took place in Jiaobei terrane at ∼2.9, ∼2.7 and ∼2.5Ga.•The ∼2.9 and ∼2.5Ga rocks represent two periods of crustal growth.•The ∼2.7Ga TTGs most likely reflect reworking of ...pre-existing ∼3.0Ga crust.•The ∼2.5Ga sanukitoids are probably derived from a metasomatized mantle source.•The mantle is likely metasomatized by slab-derived fluids, not solely by TTG melts.
U–Pb zircon dating for 10 rock samples collected from the Archean Jiaobei terrain of the eastern block of the North China craton (NCC) yield three groups of ages: ∼2.9Ga, ∼2.7Ga and ∼2.5Ga. Thirteen rock samples studied can be classified into a low Mg# (molecular Mg/(Mg+Fe)) (Mg#=34–52) and a high Mg# group (Mg#=52–61), respectively. The low Mg# rocks are typical Archean TTGs with emplacement ages of ∼2.9Ga, ∼2.7Ga and ∼2.5Ga whereas the high Mg# rocks are Archean sanukitoids with age of ∼2.5Ga. Despite having different ages, all the Jiaobei TTGs have zircon δ18O values between 5.6‰ and 6.3‰, essentially identical to those of the ∼2.7Ga TTGs from adjourning Taishan area and Archean TTGs from other parts of the world. Magmatic zircons from the Jiaobei sanukitoids have δ18O values between 6.4‰ and 7.5‰, significantly higher than the Archean TTGs. The whole-rock Nd and the zircon Hf isotopic compositions indicate that the ∼2.9Ga and ∼2.5Ga TTGs and ∼2.5Ga sanukitoids represent crustal growth at ∼2.9Ga and ∼2.5Ga in the Jiaobei terrain. Unlike the ∼2.7Ga TTGs in the adjourning Taishan area that are considered to reflect juvenile crust, the Jiaobei ∼2.7Ga TTGs, however, are most likely resulted from the reworking of the pre-existing ∼3.0Ga crust. This is in contrast to the previous suggestion that ∼2.7Ga is the most significant crust-forming episode and ∼2.5Ga a period of crustal reworking in the Jiaobei terrain. The high Mg# and high contents of Cr, Ni, LREE and LILE of the ∼2.5Ga Jiaobei sanukitoids, require a metasomatized peridotitic mantle source for their origin. The significant negative Zr and Hf anomalies and the elevated δ18O values of the ∼2.5Ga sanukitoids, are inconsistent with a mantle source metasomatized solely by the TTG melts. Instead, we suggest that the Jiaobei sanukitoids could have originated from a mantle wedge metasomatized by a high δ18O component, most likely the slab-derived fluids. The similarity of multi-element patterns and the zircon δ18O values between the Jiaobei and Superior Province sanukitoids may imply similar processes involved to form sanukitoids in both Jiaobei and Superior Province terrains.
•Tadpole diversity varied along an elevational gradient.•Tadpole diversity was determined by microhabitat variables.•Tadpole community structure was more clustered in the low and high elevational ...streams.•Tadpole community structure was more dispersed in the mid-elevation streams.
Understanding the spatial patterns and the maintenance of biodiversity is a central target in ecology and biogeography, which provide important insights into community assembly processes. Mountain ecosystems provide informative systems for examining how biodiversity is distributed and identifying the mechanisms underlying those patterns. However, most of the existed studies only focused on plants, birds, and microbes, while little attention has been paid on amphibians, especially tadpoles. In the present study, we explored the elevational patterns of multiple facets of tadpole diversity and the community assembly mechanisms in temperate montane streams of Mount Emei, China. The taxonomic, functional, and phylogenetic diversity of tadpole assemblages in montane streams were quantified. Their elevational patterns were investigated using first and second-order polynomial regression analyses. The microhabitat determinants of these patterns were assessed by ordinary least squares models and hierarchical partitioning analyses. The phylogenetic tree of tadpoles and the Eucliden distance of traits between tadpoles were constructed. They were subsequently used to calculate the standardized effect size of mean pairwise phylogenetic and functional distances, and to speculate the tadpole assembly rules. Our results indicated that the Faith’s PD and the standardized effect size of Faith’s PD had hump-shaped responses to elevation, while the relationships between elevation and observed taxonomic diversity, observed functional diversity, and the standardized effect size of functional diversity were not significant. Interestingly, these patterns were determined by microhabitat variables, such as water conductivity, river width, water depth, and substrate type. Mean pairwise phylogenetic distance also showed hump-shaped correlations with the elevational gradient. Tadpole functional and phylogenetic structures were more clustered in low and high elevational streams, suggesting that environmental filtering was the main driver. At mid-elevations, functional and phylogenetic structures were overdispersal, indicating that limiting similarity plays a dominant role in shaping the tadpole assemblages.
Basaltic underplating revealed by lower crustal xenoliths is usually considered to be manifested by younger zircon ages than those of the pre-existing crust and/or Sr–Nd isotopic heterogeneity ...resulting from mixing between mantle-derived basaltic melts and crust. The Hannuoba mafic lower crustal xenoliths have long been regarded as a typical example of Mesozoic underplating owing to the presence of 80–160 Ma zircons and evolved Sr–Nd isotopic compositions. However, our integrated study shows that most Mesozoic zircons in the Hannuoba mafic xenoliths precipitated from partial melts derived from the ancient lower crust. Although a few young zircons may record Mesozoic underplating, none of the xenoliths are products of Mesozoic underplating. It provides the first direct evidence that some zircons in lower crustal xenoliths could be exotic. The contrasting O–Hf isotopic compositions of Mesozoic zircons from the Hannuoba lower crustal xenoliths allow us to distinguish zircons that were grown from different hydrous melts from those that represent recrystallized pre-existing zircons. This has major implications for geological interpretation of the age diversity commonly observed in deep-seated xenoliths worldwide. Furthermore, at Hannuoba both the ∼1.8 Ga zircon ages from the granulite terrain and most of the 1.8–1.9 Ga zircon ages from a previously reported banded granulite xenolith also reflect metamorphism rather than underplating. It demonstrates that high-grade metamorphism or partial melting of Archean rocks can result in zircons with significantly younger U–Pb and THfDM ages. We infer that some granulite xenoliths previously regarded as products of Paleoproterozoic basaltic underplating from other regions (e.g., the Wyoming craton and the Siberian craton) may actually be remnants or derivatives of the pre-existing Archean lower crust. The large range in Sr–Nd isotopic compositions for various Hannuoba lower crustal xenoliths is unlikely to have resulted from mixing between basaltic melts and crust but was rather inherited from the ancient lower crust. Most of the Hannuoba mafic xenoliths can be best explained as residues left after partial melting of the late Archean lower crust that may be represented by the granulite terrain to produce the voluminous 125–143 Ma intermediate–felsic magmatic rocks. Therefore, young zircon ages and heterogeneous Sr–Nd isotopic compositions are insufficient criteria to infer recent underplating. Combined with literature data, it shows that Archean mafic granulite xenoliths are widespread globally, thus arguing against previous suggestion that mafic granulites from the lower crust of most Archean cratons might have formed from post-Archean basaltic underplating. It is implied that the role of basaltic underplating in the evolution of the lower crust in many regions may need to be re-evaluated.
Concrete, as an engineering material with extremely wide applications, is widely used in various infrastructure projects such as bridges, highways, and large buildings. However, structures such as ...highways and bridges often need to be situated in variable and harsh service environments for long periods. They not only face cyclic reciprocating vehicle loads but also have to contend with the effects of temperature cycling. Therefore, studying the impact and mechanism of temperature differential cycling on the compressive strength and fatigue life of cement concrete has certain theoretical significance and practical value. This study employed a comprehensive experimental design to investigate cement concrete specimens subjected to typical temperature variations (20-60 °C) and different numbers of temperature differential cycling (0, 60, 120, 180, 240, 300). Axial compressive strength tests, ultrasonic tests, and compressive fatigue tests were conducted. The axial compressive strength test measured the compressive strength of the cement concrete. It was found that with an increase in the number of temperature differential cycling, the compressive strength exhibited a trend of an initial increase followed by a decrease: at 60 cycles, the strength increased by 10.8%, gradually declined; returned to near-initial strength at 120 cycles, and continued decreasing, reaching a decline of 19.4% at 300 cycles. The ultrasonic test measured the ultrasound velocity of the concrete specimens after different temperature differential cycling. It revealed a decreasing trend in ultrasound velocity with an increase in times of temperature differential cycling, showing a strong linear relationship between the ultrasound velocity loss and strength loss, confirming the correlation between the degree of concrete strength degradation and internal damage. The compressive fatigue test analyzed the fatigue life variation in cement concrete under different times of temperature differential cycling and stress levels, showing good adherence to the Weibull distribution pattern. Based on the approximation assumptions of log-normal distribution and the Weibull distribution, the Weibull distribution parameters for the compressive fatigue life of cement concrete under temperature differential cycling were obtained.
The paper presents a comprehensive review on a variety of tradable mobility permits (TMP) schemes that are proposed as an innovative way of allocating roadway capacity. The study develops a ...comparative analysis and a qualitative evaluation to identify the similarities and variations among various TMP schemes. The paper summarizes both the strength and the weakness of different TMP schemes with respect to congestion reduction, market mechanism, and equity issues. A comparison between three typical TMP schemes and congestion pricing (CP) yields the following main conclusions: (i) there is no general superiority between the TMP schemes and the CP; (ii) various TMP schemes are unlikely to be combined into a general one, and should be separately designed for the particular objective and application condition; and (iii) different TMP schemes have different parts to be emphasized in the system design. The paper points out the implications for designs of pragmatic TMP schemes and the future research.
•It is the first review on the schemes based on tradable mobility permit (TMP).•The delineation of the TMP has profound impacts on the scheme design and function.•The TMP schemes have better effect on quantity control but yield additional costs.•There is no general superiority between the TMP schemes and the congestion pricing.•Different TMP schemes are applicable for different contexts.
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Exposure scenario and receptor behavior significantly affect PM2.5 exposure quantity of persons and resident groups, which in turn influenced indoor or outdoor air quality & health ...management. An Internet of Things (IoT) system, EnvironMax+, was developed to accurately and conveniently assess residential dynamic PM2.5 exposure state. A university community “QC”, as the application area, was divided into four exposure scenarios and five groups of residents. Low-cost mobile sensors and indoor/outdoor pollution migration (IOP) models jointly estimated multi-scenario real-time PM2.5 concentrations. Questionnaire was used to investigate residents' indoor activity characteristics. Mobile application (app) “Air health management (AHM)” could automatic collect residents' activity trajectory. At last, multi-scenario daily exposure concentrations of each residents-group were obtained. The results showed that residential exposure scenario was the most important one, where residents spend about 60 % of their daily time. Closing window was the most significant behavior affecting indoor contamination. The annual average PM2.5 concentration in the studied scenarios: residential scenario (RS) < public scenario (PS) < outdoor scenario (OS) < catering scenario (CS). Except for CS, the outdoor PM2.5 in other scenarios was higher than indoor by 5–10 μg/m3. The multi-scenario population weighted annual average exposure concentration was 37.1 μg/m3, which was 78 % of the annual average outdoor concentration. The exposure concentration of 5 groups: cooks > outdoor workers > indoor workers > students > the elderly, related to their daily activity time proportion in different exposure scenario.
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