Morphological and Sulfur-Isotopic Characteristics of Pyrites in the Deep Sediments from Xisha Trough,South China Sea

Pyrite is one of the common authigenic minerals in marine sediments.Previous studies have shown that the morphological and isotopic characteristics of pyrite are closely related to the geochemical environment where it is formed.To better understand the for-mation mechanism of authigenic pyrite,we analyzed the isotopic composition,morphology,and distribution of pyrite in the sediment at 500m below the seafloor from Xisha Trough,South China Sea.Mineral morphologies were observed by scanning electron micros-copy and Raman spectrography.X-Ray computed tomography was applied to measure the particle size of pyrite.The size of pyrite crystals in the matrix sediment mainly ranged between 25 and 65µm(av.ca.40µm),although crystals were larger(av.ca.50μm)in the veins.The pyrites had a fine-grained truncated octahedral shape with occasionally well-developed growth steps,which implies the low growth rate and weak anaerobic oxidation of methane-sulfate reduction when pyrite was formed.Theδ^(34)S values of pyrites ranged from+20.8‰Vienna-defined Canyon Diablo Troilite(V-CDT)to+33.2‰V-CDT and from+44.8‰V-CDT to+48.9‰,which suggest two growth stages.In the first stage,with the continuous low methane flux,the pyrite possibly formed in an environment with good access to seawater.In the second stage,the pyrites mainly developed in sediment fractures and appeared in veins,probably due to the limited availability of sulfate.The less exposure of pyrite to the environment in the second stage was probably caused by sediment accumulation or perturbation.In this study,an episodic pyritization process was identified,and the paleoenvironment was reconstructed for the sediment investigated.

Persistent Variations in the East Asian Trough from March to April and the Possible Mechanism

The East Asian trough(EAT)profoundly influences the East Asian spring climate.In this study,the relationship of the EATs among the three spring months is investigated.Correlation analysis shows that the variation in March EAT is closely related to that of April EAT.Extended empirical orthogonal function(EEOF)analysis also confirms the co-variation of the March and April EATs.The positive/negative EEOF1 features the persistent strengthened/weakened EAT from March to April.Further investigation indicates that the variations in EEOF1 are related to a dipole sea surface temperature(SST)pattern over the North Atlantic and the SST anomaly over the tropical Indian Ocean.The dipole SST pattern over the North Atlantic,with one center east of Newfoundland Island and another east of Bermuda,could trigger a Rossby wave train to influence the EAT in March−April.The SST anomaly over the tropical Indian Ocean can change the Walker circulation and influence the atmospheric circulation over the tropical western Pacific,subsequently impacting the southern part of the EAT in March−April.Besides the SST factors,the Northeast Asian snow cover could change the regional thermal conditions and lead to persistent EAT anomalies from March to April.These three impact factors are generally independent of each other,jointly explaining large variations in the EAT EEOF1.Moreover,the signals of the three factors could be traced back to February,consequently providing a potential prediction source for the EAT variation in March and April.

Improving Heat Transfer in Parabolic Trough Solar Collectors by Magnetic Nanofluids

A parabolic trough solar collector(PTSC)converts solar radiation into thermal energy.However,low thermal efficiency of PTSC poses a hindrance to the deployment of solar thermal power plants.Thermal performance of PTSC is enhanced in this study by incorporating magnetic nanoparticles into the working fluid.The circular receiver pipe,with dimensions of 66 mm diameter,2 mm thickness,and 24 m length,is exposed to uniform temperature and velocity conditions.The working fluid,Therminol-66,is supplemented with Fe3O4 magnetic nanoparticles at concentrations ranging from 1%to 4%.The findings demonstrate that the inclusion of nanoparticles increases the convective heat transfer coefficient(HTC)of the PTSC,with higher nanoparticle volume fractions leading to greater heat transfer but increased pressure drop.The thermal enhancement factor(TEF)of the PTSC is positively affected by the volume fraction of nanoparticles,both with and without a magnetic field.Notably,the scenario with a 4%nanoparticle volume fraction and a magnetic field strength of 250 G exhibits the highest TEF,indicating superior thermal performance.These findings offer potential avenues for improving the efficiency of PTSCs in solar thermal plants by introducing magnetic nanoparticles into the working fluid.

Geological characteristics of the southern segment of the Late Sinian–Early Cambrian Deyang-Anyue rift trough in Sichuan Basin, SW China

Based on the latest drilling, seismic and field outcrop data, the geological characteristics(e.g. strata, development and sedimentary evolution) of the southern segment of the Late Sinian–Early Cambrian Deyang–Anyue rift trough in the Sichuan Basin are analyzed. First, the strata in the southern segment are complete. The first to second members of Dengying Formation(Deng 1 + Deng 2) are found with relatively stable thickness(400–550 m), and the third to fourth members(Deng 3+ Deng 4) show great thickness difference between the marginal trough and the inner trough, which is up to 250 m. The Cambrian Maidiping Formation and Qiongzhusi Formation in southern Sichuan Basin are relatively thin, with the thickness changing greatly and frequently. Second, the Deyang–Anyue rift trough extended southward during the Deng 4 period, affecting southern Sichuan Basin. Compared to the middle and northern segments of the rift trough, the southern segment is generally wide, gentle and shallow, with multiple steps, and alternating uplifts and sags, which are distributed in finger shape. Third, the Deng 1 + Deng 2 in southern Sichuan Basin records the dominance of carbonate platform and unobvious sedimentary differentiation, and the Deng 4 exhibits obvious sedimentary differentiation, namely, basin–slope–secondary slope–slope–secondary slope–platform margin–restricted platform, from the inner trough to the marginal trough. Fourth, the rift trough in southern Sichuan Basin has evolved in four stages: stabilization of Deng 1–Deng 2, initialization of Deng 3–Deng 4, filling of Maidiping–Qiongzhusi, and extinction of Canglangpu Formation.

Clinical Evaluation of a Vancomycin Dosage Strategy Based on a Serum Trough Concentration Model in Elderly Patients with Severe Pneumonia

Objective This study aimed to evaluate the clinical benefits of a vancomycin dosage strategy based on a serum trough concentration model in elderly patients.Methods This prospective single-center, open-label, randomized controlled trial categorized 66 elderly patients with severe pneumonia into study and control groups. The control group received vancomycin using a regimen decided by the attending physician. Meanwhile, the study group received individualized vancomycin therapy with a dosing strategy based on a serum trough concentration model. The primary endpoint was the proportion of patients with serum trough concentrations reaching the target values.The secondary endpoints were clinical response, vancomycin treatment duration, and vancomycinassociated acute kidney injury(VA-AKI) occurrence.Results All patients were at least 60 years old(median age = 81 years). The proportion of patients with target trough concentration achievement(≥ 15 mg/L) with the initial vancomycin regimen was significantly higher in the study group compared to the control group(75.8% vs. 42.4%, P = 0.006).Forty-five patients(68.2%) achieved clinical success, the median duration of vancomycin therapy was10.0 days, and VA-AKI occurred in eight patients(12.1%). However, there were no significant differences in these parameters between the two groups. The model for predicting vancomycin trough concentrations was upgraded to: serum trough concentration(mg/L) = 17.194-0.104 × creatinine clearance rate(mL/min) + 0.313 × vancomycin daily dose [mg/(kg·d)].Conclusion A vancomycin dosage strategy based on a serum trough concentration model can improve the proportion of patients achieving target trough concentrations in elderly patients with severe pneumonia.

The Mamfe Basin in the southern Benue trough extension between Cameroon and Nigeria:Gem origin and problem of lithostratigraphic nomenclature and marine transgression

The Mamfe Basin has been the subject of many studies,but some debates persist,especially concerning the stratigraphic nomenclature,corundum origin,and marine transgression.The aims of this work are(1)to propose a new lithostratigraphic nomenclature of the Mamfe Basin formation based on new field observations,(2)to determine the source rock distribution and the origin of gem deposits and(3)to correlate the Cameroon section of the Mamfe Basin with the Nigerian deposits.The main results show that the name Manyu River Group is more appropriate as the Manyu River crosses all the facies in the Mamfe sedimentary Basin belonging to the Manyu Division.According to the facies analysis,the age of deposition,the mineralogic and geochemical data such as the V vs.Al2O3andΣREE vs.Al_(2)O_(3),TiO_(2)MgO,Na_(2)O,P_(2)O_(5),and CaO diagrams,this Group is composed of at least five Formations,including four Cretaceous Formations,from bottom to top:the Etoko Formation(alluvial and fluvial channel to fluvio-lacustrine deposits),the Nfaitok Formation(lagoonal deposits),the Bachuo Ntai Formation(fluvial braided channels or fluvio-deltaic environment)and the Eyumojock/NsanaragatiFormation(fluvio-lacustrine deposits)and the new Cenozoic Formation named Bakebe Formation(fluvio-lacustrine deposits).The gem minerals such as corundum,rutile,or tourmaline in the Cretaceous deposits of the Mamfe Basin are mainly detrital as indicated by the presence of worn shapes and fragments of these minerals.The presence of sapphire in the AlboCenomanian deposits indicates a Precambrian age of the felsic source rock,likely the plutonic rocks such as granite or pegmatite as indicated by the abundance of tourmaline and high LREE/HREE ratios(14.81–34.29)and slightly negative and positive Eu anomalies(0.85–1.15).This marine incursion in the Mamfe Basin was probably from West Nigeria,according to the geographic location of the Mamfe Basin and the general palaeogeographic evolution of the Benue Trough.

Investigation and simulation of parabolic trough collector with the presence of hybrid nanofluid in the finned receiver tube

The present study discusses the thermal performance of the receiver tube,which contains a wall with various fin shapes in the parabolic trough collector.Inserted fins and bulge surfaces of the inner wall of the receiver tube increase the turbulent fluid flow.In pursuance of uniform distribution of heat transfer,various fin shapes such as square-shape,circle-shape,triangle-shape,and combined square-circle shapes were inserted,examined,and compared.A study of the temperature differences and fluid flow is meaningful for this project therefore finite volume method was used to investigate heat transfer.Also,hybrid Nano-Fluid AL_(2)O_(3-)CuO,TiO_(2-)Cu,and AgMgO were applied to increase thermal diffusivity.When the combined square-circle-shaped fin was inserted,the thermal peak of fluid flow in the receiver tube was lower than the other studied fin shapes by almost 1%.Besides,the hybrid nano-fluid Ag-MgO Syltherm-oil-800 has lower thermal waste in comparison to others by more than 3%.

Modified Circumpolar Deep Water inflow to the Dotson-Getz Trough in the summers of 2020 and 2022

The melting of the West Antarctic Ice Shelf has increased since the 1990s,driven by the relatively warm Circumpolar Deep Water(CDW)that penetrates into the West Antarctic Ice Shelf cavities through submarine glacial troughs across the continental shelf.In this study,temperature,salinity,and current velocity data obtained by the Chinese National Antarctic Research Expedition in the Dotson-Getz Trough(DGT)shows clear differences in distribution of modified Circumpolar Deep Water(mCDW)in the summers of 2020 and 2022.Combined with contemporaneous wind data and additional temperature and salinity data from instrumented seals,the processes and mechanisms responsible for this variation are discussed.Compared with 2020,there is a significant increase in mCDW thickness in 2022,with a doubling of total heat content as the mCDW inflow path across the DGT shifts towards the eastern bank.We propose that a southward shift in the westerly winds in the summer of 2022 moved the upper oceanic divergence zone southward towards the continental slope,promoting the upwelling of mCDW above 500 m.Concurrently,stronger westerly winds over the continental slope strengthened the eastward undercurrent,increasing the transport of this mCDW and its associated heat content to the DGT through Ekman dynamics.These observations show there is strong interannual variability in the strength,path and extent of mCDW inflows to the DGT and that care must be taken when planning observation programs for long-term monitoring of the oceanic heat input to the ice shelves of this globally significant region.

Effect of Different Silica Fumes on Properties of Al_(2)O_(3)-SiC-C Castables for Iron Trough

In order to improve the performance of Al_(2)O_(3)-SiC-C castables for iron trough,samples were prepared using brown corundum,dense corundum,activated alumina micropowder,ball pitch,and silicon as main raw materials,calcium aluminate cement as the binder.Several kinds of silica fumes(93SiO_(2),96SiO_(2),and 99SiO_(2))with different particle size distributions and chemical composition were added to research the effects on the properties of castables.The results show that the sample with 99SiO_(2) fume has high water requirement for molding,but the bulk density is the lowest,the apparent porosity is the highest,the oxidation resistance is the worst,and the permanent linear change on heating is low after firing at 1 450 ℃ for 3 h.The bulk density and the apparent porosity of the sample with 93SiO_(2) fume or 96SiO_(2) fume are equivalent,the hot modulus of rupture of the sample with 93SiO_(2) fume is the lowest,and the slag resistance of the sample with 96SiO_(2) fume is the best.The comprehensive performance of the sample with 96SiO_(2) fume is the best.

Evaluating Vancomycin Clinical Outcomes Using Area under the Curve versus Trough Based Dosing Strategies

Background: The 2020 consensus guidelines recommend AUC guided dosing as the preferred monitoring method for vancomycin. AUC based dosing has shown to reduce incidence of acute kidney injury (AKI), utilize lower daily doses in obese patients, and maintain efficacy. Several institutions have adjusted their protocols to utilize AUC guided dosing. However, there are limited studies comparing the clinical outcomes of AUC versus trough monitoring. Methods: This was a retrospective, observational, single centered study. The primary outcome was to evaluate the clinical success of AUC dosing versus trough based dosing of vancomycin for MRSA infections using a composite outcome of afebrile post treatment ( Results: Forty-seven patients were included in this study, 17 in the AUC group and 30 in the trough group. The primary composite outcome showed a significant benefit of AUC dosing (p = 0.04). The composite component culture clearance showed the largest improvement for the AUC group when compared with the trough group (p = 0.03). More patients achieved therapeutic target attainment and reached the target sooner (3 days versus 4 days, p = 0.2) in the AUC group. Over the study course, 94.1% of patients in the AUC group were considered therapeutic compared to 63.8% in the trough group (p = 0.03). Vancomycin levels were collected less frequently in the AUC group (3 versus 4, p = 0.2). Conclusion: The outcomes of this study may suggest AUC guided dosing as a beneficial alternative to trough based dosing. AUC based dosing may improve clinical success which can be further explored in larger prospective clinical trials.

Management of tear trough deformity with and without tear trough-orbicularis retaining ligament complex release in transconjunctival blepharoplasty: a comparative study

AIM: To evaluate the effect of releasing the orbicularis retaining ligament(ORL) complex of the tear trough combined with the transconjunctival blepharoplasty in the surgical management of tear trough deformity compared with the effect of blepharoplasty alone. METHODS: A prospective, randomized(by closed envelope technique), controlled surgical trial which included 50 patients(100 eyes) with bilateral visible tear trough deformity and lower eyelid fat bulging, was divided into two groups where 25 patients(50 eyes) had tear trough-ORL release with blepharoplasty and 25 patients(50 eyes) didn't. Qualitative and quantitative assessments of tear trough deformity were done at 6 mo postoperatively, achieving grade 0 or 1 of Barton's classification was considered a success. Standardized photographic documentation of each patient was done pre and postoperatively, also assessment of the patients' satisfaction postoperatively was done and ranked as excellent, very good, good or fair. RESULTS: There was statistically significant difference between the two groups in the overall aesthetic results postoperatively regarding the qualitative and quantitative analysis of the tear trough deformity, where patients who had tear trough-ORL complex release had more successful outcomes than those of the second group. CONCLUSION: ORL release should be done in patients with tear trough deformity in order to release the tethering effect of this ligament which causes the prominence of the naso jugal groove.

Glass inclusions in volcanic rocks in the Okinawa Trough back-arc basin: constraints on magma genesis and evolution

The major element compositions of glass inclusions in plagioclase and pyroxene phenocrysts of basalt and pumice in the Okinawa Trough back-arc basin are determined by electron microprobe. The results indicate that basalt and pumice are cognate and respectively represent the products at early stages of magmatism and at late stage of crystal fractionation. The initial magma in the trough is rich in H2O. The variation of H2O content in magma may play an important role in the magma evolution. Plagioclase is the mineral crystallized throughout the whole magmatic process and accumulates in the zoned magma chamber. From these features it can be inferred that the initial magma in the Okinawa Trough, whose opening began in recent years, is seriously affected by fluid or other materials carried by subducting slab and the geochemical feature of volcanic rocks is in some degree similar to that of lavas in island-arc environments.

Mineral Chemistry Indicates the Petrogenesis of Rhyolite From The Southwestern Okinawa Trough

To reveal the petrogenesis of rhyolite from the southwestern Okinawa Trough, the mineral chemistry of plagioclase, orthopyroxene, amphibole, quartz and Fe-Ti oxide phenocrysts were analyzed using an electron microprobe, and in suit Sr and Ba contents of plagioclase analysed by LA-ICPMS were chosen for fingerprinting plagioclases of different provenances. Results indicate an overall homogeneous composition for each of the mineral phases except for plagioclase phenocrysts which have a wide range of composition(An=39~88). Plagioclase crystals characterized by An contents of >70 are not in equilibrium with their whole-rock compositions, and coarse-sieved plagioclase phenocryst interiors record high An contents(>70) and Sr/Ba ratios(>7), which are similar to the those of plagioclase crystals in basalt. Therefore, these crystals must have been introduced to the rhyolitic magma from a more mafic source. Equilibrium temperatures estimated using orthopyroxene-liquid, iron–titanium oxide, titanium-in-quartz and amphibole geothermometers show consistent values ranging from 792 to 869℃. The equilibrium pressure calculated using amphibole compositions is close to 121 MPa which corresponds to an approximate depth of 4 km. The fO_2 conditions estimated from Fe-Ti oxides and amphiboles plot slightly above the NNO buffer, which indicates that the rock formed under more oxidized conditions. Our results suggests that petrogenesis of the rhyolite due to basaltic magma ascend with the high An and Sr/Ba plaigoclases from deep magma chamber into the shallow chamber where the fractional crystallization and crustal assimilation happened. It also indicates that a two-layer magma chamber structure may occur under the southwestern Okinawa Trough.

Study on topographic compensation model of the Okinawa Trough Ⅱ. Geological interpretation of isostatic response function of the Okinawa Trough

Based on regional compensation model and experimental isostasy, the isostatic response function of the Okinawa Trough is calculated by using gravity and topographic data. The results are shown as follows: the effective elastic thickness of the plate and compensation depth in the southern Okinawa Trough is obviously greater than those in the middle Okinawa Trough. In reference with other geological and geophysical data, the differences between the two portions are explained to be caused mainly by their differences in temperature of the lithosphere and the compensation mechanism.

RESEARCH ON THE INTERANNUAL AND INTERDECADAL VARIABILITIES OF THE MONSOON TROUGH AND THEIR IMPACTS ON TROPICAL CYCLONE GENESIS OVER THE WESTERN NORTH PACIFIC OCEAN

In this paper, we mainly summarize and review the progresses in recent climatological studies(by CMSR,IAP/CAS and some associated domestic and international institutions) on the interannual and interdecadal variabilities of monsoon troughs and their impacts on tropical cyclones and typhoons(TCs) geneses over the western North Pacific Ocean. The climatological characteristics of monsoon troughs and four types of circulation patterns favorable to TCs genesis over the western North Pacific Ocean in summer and autumn are given in this paper. It is also shown in this paper that the monsoon trough over the western North Pacific Ocean has obvious interannual and interdecadal variabilities. Especially, it is revealed in this paper that the interannual and interdecadal variabilities of the monsoon trough over the western North Pacific Ocean influence the TCs genesis not only through the impact on distributions of the vorticity in the lower troposphere and the divergence in the upper troposphere, the water vapor in the mid-and lower troposphere and the vertical shear of wind fields between the upper and lower troposphere over the western North Pacific Ocean, but also through the dynamical effects of the transition between convectively coupled tropical waves and providing disturbance energy. Besides, some climatological problems associated with TCs activity over the western North Pacific Ocean that need to be studied further are also pointed out in this paper.

Rare-earth and trace elements and hydrogen and oxygen isotopic compositions of Cretaceous kaolinitic sediments from the Lower Benue Trough, Nigeria: provenance and paleoclimatic significance

This study evaluated the Cretaceous(Campanian–Maastrichtian) kaolinitic sediments of the Ajali/Mamu and Enugu/Nkporo Formations from the Lower Benue Trough of Nigeria. A combined method of inductively coupled plasma–mass spectrometry and isotope ratio mass spectrometry was used to investigate trace and rareearth element geochemistry and hydrogen and oxygen isotopic compositions. These data were then used to infer the sediments' provenance and paleoclimatic conditions during their deposition. The sediments contained low concentrations of most trace elements, with the exceptions of Zr(651–1352 ppm), Ba(56–157 ppm), V(38–90 ppm),and Sr(15.1–59.6 ppm). Average values of Co and Ni were1.5 and 0.7 ppm, respectively. Trace and rare earth element values were lower than corresponding values for upper continental crust and Post-Archean Australian Shale, with the exception of Zr. The samples showed only slight light rare-earth enrichment and nearly flat heavy rare-earth depletion patterns, with negative Eu and Tm anomalies,typical of felsic sources. Geochemical parameters such as La/Sc, Th/Sc, and Th/Co ratios support that the kaolinitic sediments were derived from a felsic rock source, likely deposited in an oxic environment.^(18 )O values ranged from+ 15.4 to + 21.2% for the investigated samples, consistent with a residual material derived from chemicalweathering of felsic rock and redeposited in a sedimentary basin(typical values of + 19 to + 21.2%). While in the basin, the sediments experienced extended interactions with meteoric water enriched in d D and d16 O. However,the variation in d D and d16 O values for the investigated samples is attributed to the high temperature of formation(54–91 °C). The d D and d^(18 )O values suggest that the sediments, although obtained from different localities within the Lower Benue Trough, formed under similar hot,tropical climatic conditions.

Study on topographic compensation model of the Okinawa Trough I. Calculation of theoretical isostatic response function

Based on regional compensation and experimental isostasy, the calculating formula of theoretical isostatic response function is deduced when the loads on top correlate with loads from below. A variety of curves of theoretical isostatic response function were calculated with different effective elastic thickness of the plate and by using different proportions between loads on top and loads from below. And preliminary discussion is made on shapes of the curves.

Linear magnetic anomalies and tectonic development of the middle Okinawa Trough

By analyzing the magnetic anomalies,the linear magnetic anomalies in the middle Okinawa Trough are identified.It means that the crust along the spreading axis is broken,and new oceanic crust is formed.Geophysical data have revealed that a model of three extensive episodes occurs in the Okinawa Trough,which can be named as“doming episode” from the Middle to Late Miocene(Phase I),the episode from the Pliocence to Early Pleistocene(Phase Ⅱ),and the recent“spreading episode”(Phase Ⅲ).The magnetic anomalies in the middle Okinawa Trough are very similar to those found in the middle Red Sea,indicating that the Okinawa Trough is developing towards the “Red Sea stage”.Similar to the Red Sea,there are a “main trough”and a “axial trough”in the Okinawa Trough.

Investigation on the Deposition in an Excavated Trough at the East Shore of Jiaozhou Bay, China

- Based on field investigations, this paper analyzes three types of harbour basinns and navigation channel excavated on seabed in Jiaozhou Bay, get a general rule of deposition for excavated trough, it found that pollution is one of crucial factors resulting in the deposition of the excavated trough in the east shore of Jiaozhou Bay. With these results, it predicted the annual deposition thickness for the excavated trough and disclosed the fact that it can’t be deposited deadly during one storm. At the same time, with two-dimensional numerical model, it studied the effects of the excavated trough and the reclamation near shore on tidal cureent and said that the excavated trough can decrease the current velocity passing through the trough about 10- 15%, but only limited inside and near the trough and there are no effect on other regions; reclamation can cut off the pollution sources and no obvious effect on the currents of the Jiaozhou Bay. Connecting the deep trough and Cangkou tidal channel with a