Global patterns of tree wood density.

Wood density is a fundamental property related to tree biomechanics and hydraulic function while playing a crucial role in assessing vegetation carbon stocks by linking volumetric retrieval and a mass estimate. This study provides a high-resolution map of the global distribution of tree wood density at the 0.01° (~1 km) spatial resolution, derived from four decision trees machine learning models using a global database of 28,822 tree-level wood density measurements. An ensemble of four top-performing models combined with eight cross-validation strategies shows great consistency, providing wood density patterns with pronounced spatial heterogeneity. The global pattern shows lower wood density values in northern and northwestern Europe, Canadian forest regions and slightly higher values in Siberia forests, western United States, and southern China. In contrast, tropical regions, especially wet tropical areas, exhibit high wood density. Climatic predictors explain 49%-63% of spatial variations, followed by vegetation characteristics (25%-31%) and edaphic properties (11%-16%). Notably, leaf type (evergreen vs. deciduous) and leaf habit type (broadleaved vs. needleleaved) are the most dominant individual features among all selected predictive covariates. Wood density tends to be higher for angiosperm broadleaf trees compared to gymnosperm needleleaf trees, particularly for evergreen species. The distributions of wood density categorized by leaf types and leaf habit types have good agreement with the features observed in wood density measurements. This global map quantifying wood density distribution can help improve accurate predictions of forest carbon stocks, providing deeper insights into ecosystem functioning and carbon cycling such as forest vulnerability to hydraulic and thermal stresses in the context of future climate change.

Near-Infrared-Induced Photothermal Enhanced Photocatalytic H2 Production for 3D/2D Heterojunctions of Snowflake-like CuS/g-C3N4 Nanosheets.

The conversion of solar power to hydrogen (H2) energy efficiently encounters some obstacles due to the lack of superior catalysts and efficient catalytic approaches. Herein, three-dimensional/two-dimensional (3D/2D) CuS/g-C3N4 photothermal catalysts were obtained via an easy, one-step hydrothermal method after pyrolysis. The favorable heterojunction interface for H2 production was constructed by snowflake-like CuS embedded in the graphite carbon nitride (g-C3N4) nanosheets, leading to the acceleration of charge transfer and separation, decrease of charge transfer distance, and perfect realization of photothermal effects (PTEs) induced by near-infrared (NIR) light. The 3D/2D CuS/g-C3N4 catalyst presents a topmost H2-production rate (1422 µmol h-1 g-1) under dual wavelength (420 + 850 nm) and a moderate H2-production rate under 420 nm, which are 12-fold and 9-fold higher than pure g-C3N4, respectively, owing to a strong action from PTEs induced by NIR. The feasible NIR-enhanced photothermal catalysis is expected to apply in multifarious heat-assisted photocatalysis processes by designing multifunctional composites with super PTE and photocatalytic capacity.

Improving global gross primary productivity estimation by fusing multi-source data products.

A reliable estimate of the gross primary productivity (GPP) of terrestrial vegetation is essential for both making decisions to address global climate change and understanding the global carbon balance. The lack of consistency in global terrestrial GPP estimates across various products leads to great uncertainty. In this study, we improve the quantification of global gross primary productivity by integrating multiple source GPP products without using any prior knowledge through the Bayesian-based Three-Cornered Hat (BTCH) method to generate a new weighted GPP data set. The fusion results demonstrate the superiority of weighted GPP, which greatly reduces the random error of individual datasets and fully takes advantage of the characteristics of multi-source data products. The weighted dataset can largely reproduce the interannual variation of regional GPP. Overall, the merging scheme based on the BTCH method can effectively generate a new GPP dataset that integrates information from multiple products and provides new ideas for GPP estimation on a global scale.

Would the obtainable gross primary productivity (GPP) products stand up? A critical assessment of 45 global GPP products.

Gross primary productivity (GPP) is a vital variable of the global carbon cycle, but the quantification of global GPP is subject to significant uncertainty due to the lack of direct observations at a global scale. Here, we evaluated and compared 45 GPP products in terms of their applicability to different vegetation types at various spatiotemporal scales. The results show that 44 GPP products and obsGPP (Model Tree Ensemble GPP derived from observations and named obsGPP) have similar global patterns with correlation coefficients greater than 0.8 except for NGT, where GOSIF, RS, and BESS are prominent. GPP products have the greatest variation in Suriname, with a mean 75th and 25th percentile difference value of 0.4748 (normalized), and we recommend RS, SDGVM and LPJ-wsl as they provide GPP estimates close to the average GPP. In terms of seasonal estimations, considerable disagreement occurs among the GPP products in winter, with a range from 118.76 to 314.95 gC/m2/season, among which JULES has the closest GPP value to the average GPP estimation. For studies concerning vegetation types preference is given to the LUE average GPP. The 45 GPP products are more consistent on grasslands but, have obvious differences for savannas. All GPP products have their own specific spatiotemporal scales, such as global or national scales or different seasons and different vegetation types (forest, grasslands, etc.). This study provides guidelines for selecting GPP products.

Assessment of attitudes towards methadone maintenance treatment between heroin users at a compulsory detoxification centre and methadone maintenance clinic in Ningbo, China.

BACKGROUND: In China, the Compulsory Detoxification Centres are the main response for people who use illegal drugs. Due to high relapse rates among people released from the Compulsory Detoxification Centres, it is likely that they may seek medical help, including Methadone Maintenance Treatment (MMT) services, at some point. Therefore, better understanding of the attitudes and beliefs of people in the Compulsory Detoxification Centres can help to provide more adequate response to opioid dependence. METHODS: In total, 329 detained heroin users and 112 active MMT clients were recruited from a local Compulsory Detoxification Centre and MMT clinic, respectively. The survey contained specific questions relating to attitudes and beliefs regarding MMT. RESULTS: Participants at the Compulsory Detoxification Centre and the MMT clinic expressed different opinions, regarding positive and negative attitudes and beliefs towards MMT. In addition, participants from both sites hold certain negative attitudes and beliefs about methadone despite their acknowledgement of the positive effects of MMT. Finally, participants at the Compulsory Detoxification Centre and the MMT clinic reported distinctive treatment preferences, with the former preferring community-based treatment and the latter MMT. CONCLUSIONS: Developing targeted education about MMT for people at the Compulsory Detoxification Centres could help improve access to accurate and evidence-based health and treatment information. The study may also help providers understand and adjust services needed for target population in the future.

Attitudes and knowledge about naloxone and overdose prevention among detained drug users in Ningbo, China.

BACKGROUND: To date there has been limited research on both the prevalence of overdose and drug user knowledge about overdose prevention and response methods in China. In addition, there has been no effort to integrate naloxone information and distribution into pre-release services for drug users detained in isolated compulsory detoxification facilities in China. METHODS: The authors conducted a survey of 279 heroin users in isolated compulsory detoxification centers in Ningbo, China in an attempt to evaluate the possibility of conducting prelease peer naloxone programs in Ningbo isolated compulsory detoxification centers. Respondents' demographic background, history of heroin overdoses, and attitudes/knowledge about overdose prevention and response were collected. RESULTS: While drug users in Ningbo's compulsory detoxification centers have limited understandings of how to effectively respond to overdoses, they expressed concern about the possibility of overdose, interest in participating in overdose prevention and response programs, and a willingness to help their peers. In general, there was no significant difference in history and attitudes/knowledge of overdose between male and female participants. CONCLUSION: Based on the findings of this research, our survey provides preliminary evidence that detained drug users have considerable interest in overdose prevention and response information and willingness to help peers. However, drug users in Ningbo isolated compulsory detoxification centers currently have limited understandings of effective ways of helping to prevent overdose deaths.

Temporal changes of smoking status and motivation among Chinese heroin-dependent, methadone-maintained smokers.

INTRODUCTION: The rates of cigarette smoking remain extremely high in active heroin users and methadone-maintained patients. It remains undetermined whether smoking status and motivation would be differentially affected by heroin and methadone administration. METHODS: Heroin-dependent, methadone-maintained patients were recruited in the present studies. A battery of self-report questionnaires was used in the current study, in order to assess smoking status and motivations before first heroin use, during active heroin use and after Methadone Maintenance Treatment (MMT) admission. RESULTS: An extremely high portion of participants started smoking before first heroin use. The highest level of cigarette smoking was found during the period of active heroin use, and cigarette consumption was reported to decrease after MMT admission. A wide range of smoking motivations were found before first heroin use. Moreover, "maintaining heroin pleasure" was the primary motivation for the increase in cigarette consumption during the period of active heroin use and 1h after heroin administration, while "habitual smoking" was the primary smoking motivation before first heroin use and after MMT admission respectively. CONCLUSIONS: The present study first demonstrated that the prolonged rewarding effect of heroin following cigarette smoking may account for the increase of nicotine consumption found in the heroin-dependent patients. It appears that heroin and methadone differentially influenced smoking status and motivation among heroin-dependent, methadone-maintained patients.

[Application of combination of capillary electrophoresis with laser-induced fluorescence: measurement of glutamate and arginine in PAG microdialytes of conscions morphine-withdrawal rats].

Microdialysis technique in free-moving animals can be used to monitor continuously the changes of many extracellular neurotransmitters in certain brain areas and study the relationship between neurotransmitter and functions. Using detection of capillary electrophoresis combined with laser-induced fluorescence (CE-LIF) further improves the above-mentioned technique. In the present study, fluorescein isothiocyanate (FITC) was used to derivatizate amino acid in very low concentration. We found that increasing derivatization temperature could shorten derivatization time and that the derivatizative efficiency was not different from that when experiment was performed under the traditional derivatization condition (room temperature for 16 h). We also got an optimized condition of amino acid derivatization with FITC at 30 degrees C water bath for 5 h. Using the optimized condition of amino acid derivatization, we investigated the changes in L-arginine (L-Arg) and L-glutamate (L-Glu) concentration in periaqueductal gray matter (PAG) microdialytes of free-moving morphine-withdrawal rats. The results indicated that there was no significant difference in the concentration of L-Arg and L-Glu in PAG between non-dependent and dependent rats. The concentration of L-Arg and L-Glu in PAG increased by 63% and 105%, respectively, in the first 10 min after naloxone-precipitated withdrawal and then declined gradually. These changes were in correspondence with the scores of morphine withdrawal symptom.