Loneliness and depressive symptoms among men who have sex with men in China: A cross-sectional study

BackgroundWhile psychosocial problems and their related factors in men who have sex with men (MSM) have been well documented in developed countries, there are still not many studies addressing this issue in China and the results are inconsistent. This study aimed to assess the prevalence of loneliness and depressive symptoms among MSM, examine their associated factors, and investigate potential factors moderating the link between depressive symptoms and loneliness.MethodsA cross-sectional study was conducted in Taizhou of Zhejiang Province in China between April and November 2021. Loneliness was assessed using the 3-item UCLA Loneliness Scale (UCLA-3), and depressive symptoms were measured using the Patient Health Questionaire-9 (PHQ-9). Data from 655 MSM were eligible for analysis. Logistic regression models were used to examine the associations between independent variables and the outcomes of loneliness and depression. The interaction terms were added in the models to assess the moderating effects.ResultsOf the MSM sample, 13.28 and 7.48% perceived loneliness and reported moderate-to-severe depressive symptoms, respectively. We found that participants who experienced loneliness were more likely to have younger age (OR 0.44, 95% CI 0.21, 0.93, 15–32 years as reference group), low social support (OR 3.60, 95% CI 2.14, 6.04), low self-esteem (OR 3.03, 95% CI 1.45, 6.32) and moderate-to-severe depressive symptoms (OR 5.45, 95% CI 2.66, 11.15). The participants with moderate-to-severe depressive symptoms were more likely to have low self-esteem (OR 6.78, 95% CI 3.08, 14.95) and feelings of loneliness (OR 5.51, 95% CI 2.66, 11.40). Stratified analyzes showed that the magnitude of the associations between depressive symptoms and loneliness varied in MSM with different age, marital status, and self-esteem.ConclusionOur study suggests that we need to pay attention to feelings of loneliness and depressive symptoms and their closely associated factors such as social support and self-esteem among MSM in China. The MSM who were young, not married, and had low self-esteem were especially vulnerable to the impact of depressive symptoms on loneliness

Characteristics of Mineralization-Forming Fluid and Metallogenic Mechanism for the Mianhuakeng Uranium Deposit in South China: Constraints from In Situ Geochemical Signatures and Sulfur Isotopes of Syn-Mineralization Pyrite and Pitchblende

The Mianhuakeng deposit is the most representative granite-related hydrothermal vein-type uranium deposit in South China; however, the characteristics of the mineralization-forming fluid and metallogenic mechanism are still less constrained. To address the scientific problems above, we investigated the trace element chemistry and sulfur isotope compositions in syn-mineralization pyrite and pitchblende from the Mianhuakeng uranium deposit. The trace element chemistry shows that the mineralization in the Mianhuakeng deposit belongs to an intermediate-to-low temperature hydrothermal system, which is consistent with the homogenization temperature distribution of fluid inclusions. Redox-sensitive elements (such as Co and Se) in syn-mineralization pyrite suggest a reductive nature of the mineralization-forming fluids. The fractionation between light and heavy REE in pitchblende from the Mianhuakeng deposit is most similar to those from the Changjiang pluton. The pronounced negative Eu anomaly is coincident with mineralization-bearing granites. The δ34S values of syn-mineralization pyrite range from −10.2 to −1.4‰, which is higher than those values of pyrite from granites near the studied area and lower than the δ34S values of pyrite from diabase in the ore district. The REE signatures of pitchblende and sulfur isotope composition of syn-mineralization pyrite suggest that the major U source for the Mianhuakeng deposit is most likely the Changjiang pluton, probably accompanied by the incorporation of mantle-derived fluids. The circulations of CO2-rich hydrothermal fluids leached uranium from granite source rocks, especially from the Changjiang pluton. The change of physicochemical conditions of the mineralization-forming fluid resulted in the deposition of the uranium minerals in favorable structural traps to form the hydrothermal vein-type Mianhuakeng uranium deposit

NanoSIMS element mapping and sulfur isotope analysis of Au-bearing pyrite from Lannigou Carlin-type Au deposit in SW China: New insights into the origin and evolution of Au-bearing fluids

Sulfur isotope signatures of Au-bearing pyrite from Lannigou Au deposit, a typical Carlin-type Au deposit in SW China, provide valuable information about the origin of the ore-forming minerals. Analysis by NanoSIMS was used to determine S isotope compositions of Au-bearing pyrite and to map the grain-scale distributions of Au, Cu, As and S in pyrite from the deposit. Based on different textural pattern of pyrites revealed by back-scattered electron (BSE) images, they are divided into three types: Py-1 diagenetic pyrite without core-rim structure, Py-2 pyrite with an Au-free core and a rhythmically-zoned Au-bearing rim, Py-3 Au-bearing pyrite with rhythmic zoning across the entire grain. The element distributions and S isotope compositions of four paragenetic stages are recognized on the basis of textural observation. Py-1 grains and the Au-free homogeneous cores of zoned crystals were formed in Stage 1 while the Au-bearing rims of the zoned crystals with rhythmic zonation of As and Cu, and to a lesser degree Au, were formed in two superimposed stages: stage 2 formed the inner zone that is enriched in As alone; and stage 3 formed the outer zone that is enriched in both Au and As. Other sulfides such as realgar, cinnabar and stibnite are formed in the last stage. The relationship between Au and As distributions in pyrite rim is complicated, changing from coupled to decoupled at the nanoscale. Such complexity is interpreted to reflect fluctuation of fluid composition and temperature with time, which in turn affect the modes of occurrence of As and Au. It is inferred that As mainly occurs in the crystal lattice replacing S whereas Au is mainly present as nanoparticles that were trapped in pyrite during crystal growth. The Au-bearing rims of the zoned pyrite crystals are characterized by highly variable delta S-34 values from 1.1 to 18.1 parts per thousand, which exceed the values of the Triassic calcareous host rocks (10-14 parts per thousand). In contrast, the delta S-34 values of the Au-free cores of zoned pyrite crystals vary over a narrower interval and are mainly between 6 and 12 parts per thousand, close to the values of pyrite crystals in the sedimentary country rocks. Our new analyses also reveals that the delta(34)5 values of the Au-bearing fluids generally increase during the formation of the deposit. The observed S isotope variations are consistent with mixing between a magmatic-related fluid with mantle-like delta S-34 value (similar to 0 parts per thousand) and a sedimentary or deep basin brine fluid with elevated delta S-34 value (>18 parts per thousand), with an increasing contribution from the latter with time. The notably varied values of delta(34)5 and the disseminations of Au and other trace elements such as As and Cu in pyrite crystals indicate that the process responsible for Au precipitation in this deposit occurred in an open hydro thermal system

Origin of Triassic granites in central Hunan Province, South China: constraints from zircon U–Pb ages and Hf and O isotopes

<div><p>Triassic granites crop out extensively in central Hunan Province, South China. Representative granites include the Baimashan, Weishan, and Ziyunshan plutons. Lithologically, these granites mainly comprise biotite monzogranite, two-mica granites, hornblende-biotite granite, hornblende-biotite monzogranite, and garnet-muscovite granite. These granites have <i>in situ</i> zircon secondary ion mass spectrum U–Pb ages between 223.2 ± 3.3 and 209.3 ± 4.0 Ma, indicating that they likely formed predominantly in the Late Triassic. These granitic plutons have similar zircon Hf and O isotopic compositions, with <i>ε</i>_Hf(<i>t</i>) values of −0.8 to −9.0, two-stage depleted mantle model ages (<i>T</i>_DM2) of 1.81–1.31 Ga, and weighted mean of <i>δ</i>¹⁸O_Zrc values of 8.53 ± 0.58‰ to 9.12 ± 0.28‰. Combined with U–Pb dating and Hf isotopic data, the elevated and variable <i>δ</i>¹⁸O and <i>ε</i>_Hf(<i>t</i>) values of the individual granites indicate that these Triassic granites were likely produced by partial melting of upper Paleoproterozoic to lower Mesoproterozoic metasedimentary rocks and are S-type granites. The variable proportions of inherited zircons in certain samples with U–Pb ages of 627–992 Ma indicate the involvement of lower–middle Neoproterozoic crustal materials during magma crystallization through wall-rock contamination, which resulted in the wide range of isotopic compositions. Underplating of mantle-derived magma may have provided the thermal energy for partial melting of the upper Paleoproterozoic and lower Mesoproterozoic basements, thereby generating these late Triassic granites. The lack of positive <i>ε</i>_Hf(<i>t</i>) values and high <i>δ</i>¹⁸O_Zrc values indicate that the contribution of mantle-derived magmas to these granites may be insignificant.</p></div

Is river-course change associated with the crustal movement ?

This paper presents an integrated study on the effects of human activity, climate change and crustal movement on the changes of the middle reaches of the Tarim River in China. Remote sensing images and rainfall data from 38 stations from 1970 to 2021 were used for the research. The precise point positioning (PPP) approach was applied to ascertain the crustal movement of the study area using 256 Global Positioning System (GPS) station data of the recent 20 years. The results show that in the past 50 years the studied reaches of the river has moved north at maximum 2940 m or 57.9 m on average, and human activity may have played a dominant role in this change though extreme events of climate may have also taken a part in it. However, before the Anthropocene, its northeast migration is likely associated with crustal movement as the basin bottom inclines to northeast. Highlights Remote sensing reveals a northeast movement of the Tarim River in China 256 GPS station data illustrate a northeast movement and inclination of the Tarim Basin River migration is related to human activity, climate change and crustal movement Combination of remote sensing with GPS will be a promising approach for river change analysi