Recent Climate Warming of Central China Reflected by Temperature-sensitive Tree Growth in the Eastern Qinling Mountains and its Linkages to the Pacific and Atlantic Oceans

We have developed a 202-year tree-ring width chronology of Shensi fir(Abies chensiensis) growing in an open canopy forest at the treeline of the eastern Qinling Mountains. Climate response analyses revealed that the ring width of Shensi fir trees is primarily controlled by the range of temperature from February–June. The regression model that we used for statistical temperature reconstruction passed the leave-one-out cross-validation used in dendroclimatology, resulting in a quality-controlled February–June reconstruction for the eastern Qinling Mountains. The model accounts for 36.7% of the instrumental temperature variance during the period of 1960–2012. Warm springs and early summers occurred during AD 1870–1873, 1909–1914, 1927–1958 and 1997–2012, while the periods of AD 1874–1908, 1915–1926 and 1959–1996 were relatively cold. Spatial climate correlation analyses with gridded land surface data revealed that our temperature reconstruction contains a strong regional temperature signal for central China. The linkages of ourtemperature reconstruction with sea surface temperature in the Atlantic and Pacific oceans suggest the connection of regional temperature variations to large-scale ocean–atmosphere–land circulation. Preliminary analysis of links between large-scale climatic variation and the temperature reconstruction also shows that there is a relationship between extremes in spring and early summer temperature and anomalous atmospheric circulation in the Qinling Mountains. Overall, our study provides reliable information for the research of past temperature variability in the Qinling Mountains, China.

New Discovery of Neocalamites from the Upper Triassic Daheba Formation in West Qinling, Northwest China

Objective Neocalamites is a common plant fossil from the Triassic to the Middle Jurassic. Neocalamites fossils are commonly found in coal-bearing sedimentary rocks of Rhaetian stage from South China and the Yanchang Group from North China(Mei and Liu, 2017). Moreover, the fossils also distribute in the Late Triassic such as the Babaoshan Group in Dulan and Darigemole Group in Gangcha of Qinghai Province, the Haojiagou Formation in Turpan and the Taliqike Formation in Kuche of Xinjiang.Besides,Neocalamites fossils are also found in the Early and Middle Jurassic strata of North China.

On-treatment monitoring of liver fibrosis with serum hepatitis B core-related antigen in chronic hepatitis B

BACKGROUND Non-invasive evaluation for liver fibrosis is clinically important,especially in patients with undetectable hepatitis B virus(HBV)DNA treated with nucleoside analogs.AIM To clarify the monitoring power of hepatitis B core-related antigen(HBcrAg)for hepatic histologic changes in patients with chronic hepatitis B(CHB)treated with entecavir.METHODS This prospective multicenter study used multiple ordinal and multivariate logistics regression analysis to assess variables associated with Ishak fibrosis score and regression for fibrosis regression,respectively,in 403 CHB patients,including 374 with entecavir for 72 weeks(291 underwent paired liver biopsy)and 29 as controls.RESULTS Level of HBcrAg correlated negatively with liver fibrosis staging(γ=-0.357,P<0.001)in hepatitis B e antigen(HBeAg)-positive patients,and positively with liver fibrosis staging in HBeAg-negative patients.Higher HBcrAg concentration was associated with younger age,HBeAg positive status,high HBV DNA loads,high level of hepatitis B surface antigen(HBsAg)and higher necroinflammation,but not with HBV genotype.Serum concentration of HBcrAg,basal core promoter/precore(BCP/PC)mutant,quantitation of HBsAg(qHBsAg)and platelet counts were independently associated with Ishak fibrosis score on multiple ordinal regression.HBV DNA was undetectable in 88.37%of patients treated with entecavir at week 72,while their level of HBcrAg was still detectable.A greater reduction in post-treatment HBcrAg concentration was associated with the regression of hepatic fibrosis and histological improvement.HBcrAg concentration>6.33 log IU/mL at baseline and logarithmic reduction>1.03 log IU/mL at week 72 were associated with a higher chance of regression of liver fibrosis and histological improvement,respectively.CONCLUSION HBcrAg level is associated with liver fibrosis progression.HBcrAg is an excellent monitor of hepatic histological changes,especially in CHB patients treated with nucleoside analogs.

CdS-modified one-dimensional g-C_3N_4 porous nanotubes for efficient visible-light photocatalytic conversion

A heterojunction photocatalyst based on porous tubular g-C3N4 decorated with CdS nanoparticles was fabricated by a facile hydrothermal co-deposition method.The one-dimensional porous structure of g-C3N4 provides a higher specific surface area,enhanced light absorption,and better separation and transport performance of charge carriers along the longitudinal direction,all of which synergistically contribute to the superior photocatalytic activity observed.The significantly enhanced catalytic efficiency is also a benefit originating from the fast transfer of photogenerated electrons and holes between g-C3N4 and CdS through a built-in electric field,which was confirmed by investigating the morphology,structure,optical properties,electrochemical properties,and photocatalytic activities.Photocatalytic degradation of rhodamine B(RhB)and photocatalytic hydrogen evolution reaction were also carried out to investigate its photocatalytic performance.RhB can be degraded completely within 60 min,and the optimum H2 evolution rate of tubular g-C3N4/CdS composite is as high as 71.6μmol h^–1,which is about 16.3 times higher than that of pure bulk g-C3N4.The as-prepared nanostructure would be suitable for treating environmental pollutants as well as for water splitting.

滴灌下氮肥减量配施生物炭对玉米大豆间作系统光合特性和产量的影响

为研究氮肥减量结合生物炭对玉米大豆间作群体光合特性和产量的影响,设置不同种植模式(玉米单作、大豆单作、玉米大豆间作)、生物炭(2,4,6 t·hm^(-2))、氮肥减量(165,210,255 kg·hm^(-2))三因素试验,采用正交试验设计方法,探讨不同种植模式氮肥减量配施生物炭的适宜用量。结果表明:单作与间作模式玉米适宜的用量分别为氮肥210与255 kg·hm^(-2),生物炭用量均为4 t·hm^(-2)。间作系统产量达到13395 kg·hm^(-2),较单作玉米下降20.13%,间作玉米、大豆较相应单作产量分别下降35.69%和56.39%,有效株数低是导致间作玉米产量下降的主要原因,而单位面积株数与单株粒数的合理调控是决定间作大豆产量高低的关键因素。间作处理IN3C2(氮肥225 kg·hm^(-2)、生物炭4 t·hm^(-2))玉米的Pn从大口期到灌浆期持续升高,在灌浆期达到峰值,大豆从开花期经历结荚期到鼓粒期持续升高,在鼓粒期达到峰值,较其它处理具有显著光合优势,且大豆在结荚期和鼓粒期表现显著的边际优势。综上,滴灌下,氮肥减量与生物炭配施,单作和间作玉米较优的氮肥用量分别为210和255 kg·hm^(-2),生物炭为4 t·hm^(-2)。

玉米大豆间作干物质积累和氮磷吸收利用的边际效应

【目的】研究间作对玉米大豆干物质积累及氮磷吸收利用特性的影响机制,对实现玉米、大豆间作高产高效具有重要指导意义。【方法】试验设玉米单作、大豆单作、玉米大豆间作3种种植方式,分别测定玉米大口期、吐丝期和成熟期的植株氮磷积累量和大豆开花期、结荚期和成熟期的植株氮磷积累量,研究间作对玉米、大豆不同器官干物质积累及氮磷吸收积累特性,明确氮磷吸收利用的边际效应。【结果】与单作相比,间作降低了玉米干物质和氮磷的积累,促进了根系吸收氮向籽粒的分配;降低了大豆干物质积累,尤其对中行的影响大于边行,边行干物质、氮磷积累体现边际效应优势;与单作体系相比,间作使玉米大豆植株茎叶营养器官氮转移量均减少,分别降低22.13%、29.85%,转运氮对玉米籽粒氮的贡献率分别下降5.11%、17.45%,且根系吸收氮对籽粒氮的贡献率均高于转运氮对籽粒氮的贡献率。间作能够有效提高系统氮利用效率,较玉米、大豆单作分别提高2.34%、4.62倍,使系统氮效率较单作大豆提高26.82%,较单作玉米降低10.16%,玉米在系统产量中占主导地位,占系统产量的82.27%,土地当量比(LER)达到1.47,系统产量为13110 kg/hm^(2),较单作玉米下降3.96%。【结论】间作优势主要在于促进根系吸收氮向籽粒的分配,提高氮的利用效率。

Network pharmacology studies on the effect of Chai-Ling decoction incoronavirus disease 2019

Background:Chai-Ling decoction(CLD),derived from a modification of Xiao-Chai-Hu(XCH)decoction and Wu-Ling-San(WLS)decoction,has been used to treat the early-stage of coronavirus disease 2019(COVID-19).However,the mechanisms of CLD in COVID-19 remain unknown.In this study,the potential mechanisms of CLD in COVID-19 were preliminarily investigated based on network pharmacology and molecular docking method.Methods:Initially,the active components and targets of CLD were screened based on Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform and PharmMapper database.The targets of COVID-19 were obtained from GeneCards database.The protein-protein interaction network was established using STRING database to analyze the key targets.Gene Oncology(GO)analysis and Kyoto Encyclopedia of Genes and Genomes analysis were also conducted to evaluate the pathways related to the targets of CLD on COVID-19.Moreover,the compound-target-pathway network was established using Cytoscape 3.2.7.Subsequently,the molecular docking method was performed to select the active compounds with high binding affinity on severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)and angiotensin-converting enzyme 2(ACE2),which is the key target of SARS-CoV-2 in entering target cells.The possible binding sites were also visualized by a three-dimensional graph.Results:Network pharmacology analysis showed that there were 106 active components and 160 targets of CLD.Additionally,251 targets related to COVID-19 were identified,and 24 candidates of CLD on COVID-19 were selected.A total of 283 GO terms of CLD on COVID-19 were identified,and 181 pathways were screened based on GO and Kyoto Encyclopedia of Genes and Genomes analyses.CLD might alleviate the inflammatory response and improve lung injury to treat COVID-19 through interleukin 17 signaling,T helper cell 17 differentiation,tumor necrosis factor signaling,and hypoxia inducible factor-1 signaling.Besides,molecular docking indicated that beta-sitosterol,kaempferol,and stigmasterol were the top three candidates in CLD with the highest affinity to SARS-CoV-2 and ACE2.Conclusion:Our study identifies the potential mechanisms of CLD on COVID-19 and beta-sitosterol,kaempferol,and stigmasterol may be the key compounds that exert antiviral effects against SARS-CoV-2.

Molecular mechanisms of paclitaxel and NM-3 on human gastric cancer in a severe combined immune deficiency mice orthotopic implantation model

AIM: To explore the molecular mechanisms of action of paclitaxel and NM-3 on human gastric cancer in severe combined immune deficiency (SCID) mice. METHODS: Human gastric cancer cells SGC-7901 were implanted into SCID mice and mice were treated with paclitaxel and NM-3. The effects of paclitaxel and NM-3 on apoptosis of human gastric cancer cells were analyzed using flow cytometry, TUNEL assays, and DNA fragment analyses. RESULTS: Apoptosis of SGC-7901 cells was successfully induced by paclitaxel, NM-3, and the combination of paclitaxel and NM-3 24 h after injection as shown by the presence of apoptotic hypodiploid peaks on the flow cytometer before G1-S and a characteristic apoptotic band pattern in the DNA electrophoresis. The apoptotic rate detected by TUNEL assay was found to be significantly higher in the paclitaxel/NM-3 compared to the control group (38.5% ± 5.14% vs 13.2% ± 1.75%, P < 0.01). CONCLUSION: Paclitaxel in combination with NM-3 is able to induce apoptosis of the human gastric cancer cells in SCID mice effectively and synergistically.

混合卷积神经网络用于高光谱小麦品种鉴别

不同品种的小麦满足了市场的不同需求,同时也会带来小麦品种混杂的风险。为了提高小麦品种的纯度进而提高选种、育种、加工等环节的经济价值,小麦种子的鉴别起到关键作用。传统的小麦品种纯度理化分析鉴别方法,鉴定时间长且破坏种子,已不能满足现代农业的迫切需要。高光谱成像作为近年来发展迅速的一种快速、高效、无损的新型鉴别技术,在种子品种鉴别领域取得了显著成效。然而,已有的大多数高光谱分类方法仅利用光谱信息,没有充分考虑空间信息,分类效果较差。为了解决上述问题,利用高光谱成像设备采集8个品种的小麦种子正背面的高光谱图像,基于这些高光谱数据集,提出一种基于注意力机制的混合卷积神经网络的高光谱小麦品种鉴别方法,主要利用三维卷积和二维卷积的互补优势特性提取小麦的有价值特征,进而提高小麦品种的鉴别效果。具体而言,首先提取小麦品种的感兴趣区域,并利用多元散射校正方法削弱由于散射水平差异带来的同一品种的光谱差异。同时,利用主成分分析方法减少三维数据的无用光谱波段,进而保留并压缩对鉴别小麦品种有价值的特征。随后,利用三维卷积获取空间维度和不同光谱间的特征信息,二维卷积获取空间信息和图像的自身固有的特征信息,并在二维卷积模型中引入注意力机制进一步增强图像的特征信息的提取。最后在全连接层实现同一区域不同小麦品种的鉴别。实验表明,所提出的方法比其他方法具有较好的分类性能,分类准确率达97.92%。此外,所提出的方法对小样本数据也具有较好的分类性能。总的来说,提出的方法对于高光谱小麦种子鉴别具有较好的有效性和鲁棒性,为小麦种子的在线鉴别提供了一种新的方法。

基于RBF网络的新疆特重雪灾区最大积雪深度预测研究

基于建立的雪灾灾损指数,确定新疆特重雪灾区域;进一步聚焦特重雪灾区的8个县(市),包括阿勒泰市、福海县、青河县、塔城市、托里县、沙湾市、尼勒克县和伊宁县,分别建立县域RBF网络模型,预测2021—2050年年最大积雪深度。结果表明:该模型可用于新疆特重雪灾区最大积雪深度预测,但预测精度仍有待提升;塔城市、尼勒克县将于2025—2029年连续出现最大积雪深度偏高事件,2039年青河县将出现最大积雪深度的极大值,因此应关注可能发生雪灾的年份与县(市),积极做好雪灾的防御工作。

Ag nanoparticles anchored organic/inorganic Z‐scheme 3DOMM‐TiO_(2‒x)‐based heterojunction for efficient photocatalytic and photoelectrochemical water splitting

Narrow spectral response,low charge separation efficiency and slow water oxidation kinetics of TiO_(2)limit its application in photoelectrochemical and photocatalytic water splitting.Herein,a promising organic/inorganic composite catalyst Ag/PANI/3DOMM‐TiO_(2–x)with a three‐dimensional ordered macro‐and meso‐porous(3DO MM)structure,oxygen vacancy and Ti^(3+)defects,heterojunction formation and noble metal Ag was designed based on the Z‐scheme mechanism and successfully prepared.The Ag/PANI/3DOMM‐TiO_(2–x)ternary catalyst exhibited enhanced hydrogen production activity in both photocatalytic and photoelectrochemical water splitting.The photocatalytic hydrogen production rate is 420.90μmol g^(–1)h^(–1),which are 19.80 times and 2.06 times higher than the commercial P25 and 3DOMM‐TiO_(2),respectively.In the photoelectrochemical tests,the Ag/PANI/3DOMM‐TiO_(2–x)photoelectrode shows enhanced separation and transfer of carriers with a high current density of 1.55 mA cm^(–2)at equilibrium potential of 1.23 V under simulated AM 1.5 G illumination,which is approximately 5 times greater than the 3DOMM‐TiO_(2).The present work has demonstrated the promising potential of organic/inorganic Z‐scheme photocatalyst in driving water splitting for hydrogen production.

Identification of candidate genes that regulate the trade-off between seedling cold tolerance and fruit quality in melon (Cucumis melo L.)

Trade-offs between survival and growth are widely observed in plants.Melon is an annual,trailing herb that produces economically valuable fruits that are traditionally cultivated in early spring in China.Melon seedlings are sensitive to low temperatures,and thus usually suffer from cold stress during the early growth period.However,little is known about the mechanism behind the trade-offs between seedling cold tolerance and fruit quality in melon.In this study,a total of 31 primary metabolites were detected from the mature fruits of eight melon lines that differ with respect to seedling cold tolerance;these included 12 amino acids,10 organic acids,and 9 soluble sugars.Our results showed that concentrations of most of the primary metabolites in the cold-resistant melons were generally lower than in the cold-sensitive melons;the greatest difference in metabolite levels was observed between the cold-resistant line H581 and the moderately cold-resistant line HH09.The metabolite and transcriptome data for these two lines were then subjected to weighted correlation network analysis,resulting in the identification of five key candidate genes underlying the balancing between seedling cold tolerance and fruit quality.Among these genes,CmEAF7 might play multiple roles in regulating chloroplast development,photosynthesis,and the ABA pathway.Furthermore,multi-method functional analysis showed that CmEAF7 can certainly improve both seedling cold tolerance and fruit quality in melon.Our study identified an agriculturally important gene,CmEAF7,and provides a new insight into breeding methods to develop melon cultivars with seedling cold tolerance and high fruit quality.

Implementation and uniformity calibration of LED array for photodynamic therapy

Irradiance uniformity is an important parameter for a Photodynamic Therapy(PDT)device.The calibration and verification of a LED array light source based on computer vision technology were implemented and carried out.First,the correlation coe±cients between the pulse width modulate value and the irradiance were calibrated.Then,the correction of the actual light center and divergence angle were solved by image processing to reduce errors from each LED lens.Finally,uniformity was optimized according to the irradiance formula of the Lambertian source.The lowest coe±cients of variation of irradiance were 4.87%in a 5 cm×12 cm area and 3.55%in a 3 cm×10 cm area within the depth range of 8–12 cm when the expected irradiance was 100 mW/cm^(2).This finding indicated that the light source can achieve a more uniform illumination and provide a better therapeutic effect for the PDT of port-wine stains.

Effects of Xuebijing Combined with Ulinastatin on Coagulation Function of Sepsis Patients

[Objectives] To study the effects of Xuebijing combined with ulinastatin on coagulation function of sepsis patients. [Methods]Fifty six patients conforming to the diagnosis criteria for sepsis and receiving the treatment from May 2015 to January 2019 were selected. They were randomly divided into treatment group and control group according to the order of treatment. The two groups were treated according to the International Guidelines for Management of Severe Sepsis and Septic Shock( 2012),in which ulinastatin and Xuebijing were added to the treatment group. Before the treatment and on the seventh day after the treatment,both groups of patients were measured for the activated partial thromboplastin time( APTT),fibrinogen( Fi B),platelet( PLT),and prothrombin time( PT) were measured;the treatment status of the both groups was continuously observed for 7 d,and the mechanical ventilation time,ICU hospitalization time,and 30-day survival rate were recorded. [Results] Both FIB and PLT of the treatment group were significantly increased,and both APTT and PT were significantly shortened.Compared with the control group,the difference was statistically significant( P < 0. 05). The mechanical ventilation time and ICU hospitalization time of the treatment group were significantly shorter than that of the control group,and the 30-day survival rate of the treatment group was significantly higher than that of the control group,and the difference was statistically significant( P < 0. 05). [Conclusions]Xuebijing combined with ulinastatin can improve coagulation disorders of sepsis patients.

子宫内膜异位症患者血清CTRP3、Apelin水平与痛经程度、不孕不育关系

目的:探讨子宫内膜异位症(EMS)患者血清补体C1q/肿瘤坏死因子相关蛋白3(CTRP3)、孤独G蛋白耦联受体配体(Apelin)水平及与痛经程度、不孕不育的关系。方法:回顾性收集2019年5月-2022月5月本院收治的EMS患者305例为EMS组,年龄相近的健康体检女性260例为对照组。入院后均采用酶联免疫吸附法检测血清CTRP3、Apelin水平,并采用Spearman相关分析与患者痛经程度关系,采用受试者工作特征(ROC)曲线评估血清CTRP3、Apelin预测EMS合并不孕不育价值。结果:EMS组血清CTRP3(256.63±72.68 ng/ml)低于对照组(465.63±50.41 ng/ml),血清Apelin(4.52±1.96μg/L)高于对照组(1.98±0.36μg/L),且随着EMS痛经疼痛加重血清CTRP3水平逐渐降低、血清Apelin水平逐渐升高,合并不孕不育患者血清CTRP3低于未合并不孕不育患者、Apelin水平高于未合并不孕不孕患者(均P<0.05)。Spearman相关分析显示,CTRP3患者血清CTRP3与痛经程度呈负相关,血清Apelin与痛经程度呈正相关(均P<0.05)。ROC曲线分析,血清CTRP3、Apelin预测子宫内膜异位症合并不孕不育的曲线下面积分别为0.864、0.755,截断值分别为240.36ng/ml、4.02μg/L,敏感度分别为92.3%、92.3%,特异度分别为66.4%,57.1%,二者联合预测的曲线下面积为0.905,敏感度86.6%、特异度85.5%。结论:EMS患者血清CTRP3水平降低、Apelin水平升高,且二者水平与痛经程度密切相关,并有望成为预测EMS合并不孕不育指标。

花生栽培种和野生种Arachissp.30119六倍体杂种的创制与鉴定

【目的】花生野生种包含许多优异的抗病虫基因,是栽培种改良的重要基因资源库,将野生种染色质导入栽培种是花生远缘杂交研究的重要目的。野生种A.sp.30119对多种花生病害具有抗性,研究其与栽培种的杂种后代,为明确A.sp.30119的身份和未来能够利用其优异抗性提供依据。【方法】利用异源四倍体花生栽培品种白突131与二倍体野生种A.sp.30119杂交,通过胚拯救获得种间杂种F1(W1212),但F1不结实。为了揭示W1212不结实的原因并获得可育的后代,先利用根尖细胞有丝分裂中期和花粉母细胞染色体制片,观察其染色体数目和减数分裂染色体联会情况,再利用试管苗染色体加倍方法对W1212进行加倍处理,最终收获4个单粒荚果,将其中一个荚果的种子组织培养成完整植株并命名为Am1212。利用顺序GISH/FISH和SSR标记分析Am1212的染色体组成,并观察调查其表型特征。最后,利用rDNA FISH随机分析8个Am1212的F3代植株的有丝分裂中期染色体数目,评价其染色体遗传稳定性。【结果】白突131与A.sp.30119的杂种一代W1212花粉母细胞减数分裂中期Ⅰ的染色体平均构型为1Ⅲ+6Ⅱ+15Ⅰ,其染色体不能正常配对,表现为高度不育,染色体加倍处理后W1212下针枝条的花粉育性显著提高。白突131、A.sp.30119和Am1212的顺序GISH/FISH分析结果表明,A.sp.30119可能为A基因组二倍体野生种。Am1212有60条染色体,包含白突131与A.sp.30119的全部染色体,证实其为六倍体杂种后代。但Am1212自交F3代有37.5%的植株发生了染色体数目变异。通过分子标记筛选和表型调查,获得17个特异追踪A.sp.30119的显性和共显性标记,明确了Am1212的遗传特性。【结论】创制了一个新的六倍体花生Am1212,该六倍体整合了野生种染色质,同时,Am1212也拥有了小荚果等不利性状,且染色体遗传稳定性较差,因此,未来育种利用过程中,需要结合精准的染色体鉴定技术,打破不良连锁,获得具有补偿效应且包含有利性状的染色体变异材料。

基于光偏转原理的AFM光电检测系统设计

利用光偏转原理设计并实现了原子力显微镜(AFM)的光电检测系统,研究了影响光偏转噪声的影响因素。设计了新型螺旋式嵌套结构调节准直光斑,使激光发散角降低到0.053°,利用压电陶瓷特性设计了高精度三维调节结构,可以在α,β,γ方向精准调节偏转角度,36mm的聚焦焦距满足了小型化、集成化的设计目标。基于该高灵敏度光电检测系统的设计,AFM系统得到了清晰的硅材料表面台阶结构,系统分辨率达到了0.1nm,为今后的亚原子测量奠定了实验基础。

天山北坡西部雪岭云杉海拔梯度生态弹性变化

基于天山北坡西部温泉哈夏林区间隔100 m海拔高度采集的雪岭云杉梯度样本的断面积生长量资料,分析树木生态弹性变化。干旱事件是区域生态弹性最主要的干扰因子,高温事件也是干扰因子之一。干扰因子的强度会造成生态弹性梯度特征的变化。在极端干旱年份,哈夏林区梯度生态弹性特征最显著,即中高海拔为强抵抗力和弱恢复力,而低海拔则呈相反态势,并出现生长衰退现象。中旱事件时不同海拔均为强抵抗力和较强的恢复力,高温年份低海拔呈现弱抵抗力和弱恢复力。在发生持续干旱时,不同海拔高度的树木生长均受到遏制,但低海拔衰退强度大于高海拔区域,高海拔区域树木对干旱的适应能力要强于中低海拔。

祖厉河水生生物群落结构特征及多样性评价

大型底栖动物及鱼类是河流水生态健康评价的主要物种,针对祖厉河水生生物现状底数不清、生物群落结构不明现状,选取干流及最大支流的5个水文断面对大型底栖动物和鱼类进行监测,分析其组成、密度及生物量,采用香农-威纳多样性指数和BMWP指数对其多样性分布格局、时空分布特征进行评价,并探索分析了水生生物多样性与水质环境的相关性,为祖厉河生态保护治理提供技术支撑。调查结果显示,大型底栖无脊椎动物28属种,隶属于3门3纲,其中,节肢动物24属种,占总种数的78.57%,为优势种。鱼类种数较少,共有7种,均隶属于鲤形目,斯氏高原鳅为优势种。从水生生物香农-威纳多样性指数来看,祖厉河大型底栖无脊椎动物的多样性为中等,BMWP指数为较差,而鱼类多样性总体较差。干流和支流的大型底栖无脊椎动物都呈现上游大于下游、夏季大于秋季的趋势。祖厉河支流的鱼类较干流较多。同时,水生生物多样性与水质环境相关分析显示,水温、高锰酸钾指数、氨氮、总氮、总磷、溶解氧是影响底栖动物群落结构及生物多样性的主要驱动因子;鱼类的种类数与氨氮呈显著性负相关(p>0.05),水温与香农-威纳多样性指数呈显著性负相关(p>0.05),由于鱼类种数较少,相关性显著不明显。

卵巢过度刺激综合征患者的护理干预研究现状

卵巢过度刺激综合征(ovarian hyperstimulation syndrome,OHSS)发病率随着应用辅助生殖技术人数的增加而不断升高,对患者身心健康及家庭生活质量均造成了极大的困扰。因此,采取有效的干预措施对OHSS患者极为重要。本文通过对OHSS的概念、发病机制、临床表现、治疗方式、护理研究现状、可借鉴的护理干预方法进行归纳,为OHSS患者的临床护理提供新的思路。