水分梯度下胡杨荒漠河岸林种内竞争及空间格局变化特征

为查明塔里木河下游不同水分梯度下胡杨种内竞争以及空间分布格局的变化规律,在塔里木河下游阿拉干断面选取3条样带,每条样带内依照水分梯度布设3个样方,采用Hegyi单木竞争模型与点格局等分析方法,探究了水分梯度下胡杨林种内竞争及空间格局变化特征。结果表明：1)塔里木河下游胡杨的最适竞争范围为10m; 2)胡杨竞争指数与胸径服从幂函数关系(P<0.001),胡杨竞争指数随对象木胸径的增加而逐渐减小,当对象木胸径达到20cm以上时,其竞争指数逐渐稳定,且维持在较低水平;3)随水分梯度的降低,胡杨林分竞争指数呈下降趋势;4)在塔里木河下游,胡杨空间格局主要为聚集分布,随空间尺度的增加,胡杨逐渐趋向于随机分布;5)随水分梯度的降低,胡杨空间格局由聚集分布逐渐转变为随机分布。水分是决定极端干旱区荒漠植被空间分布与结构的主要因子;在胡杨林分管理中,应充分考虑胡杨的种内竞争、空间格局及其与水分梯度之间关系,为塔里木河下游胡杨林的保护与更新提供科学依据。     

游离睾酮指数联合血清GnSAF、SHBG对多囊卵巢综合征不孕患者IVF-ET治疗妊娠结局的预测价值

摘要 目的：探讨游离睾酮指数（FAI）联合血清促性腺激素平抑因子（GnSAF）、性激素结合球蛋白（SHBG）对多囊卵巢综合征（PCOS）不孕患者体外受精-胚胎移植（IVF-ET）治疗妊娠结局的预测价值。方法：选取2020年1月～2022年6月湖南省妇幼保健院生殖医学中心收治的197例PCOS不孕患者为PCOS组,根据IVF-ET治疗妊娠结局分为妊娠失败组和妊娠成功组,另选取同期68名体检健康妇女为对照组。收集PCOS不孕患者临床资料,计算FAI并检测血清GnSAF、SHBG水平。采用单因素和多因素Logistic回归分析PCOS不孕患者IVF-ET治疗妊娠结局的影响因素,采用受试者工作特征（ROC）曲线分析FAI和血清GnSAF、SHBG对PCOS不孕患者IVF-ET治疗妊娠结局的预测价值。结果：PCOS组FAI和血清GnSAF水平高于对照组,SHBG水平低于对照组（P＜0.05）。197例PCOS不孕患者IVF-ET治疗妊娠成功率为51.27%（101/197）。单因素分析显示,妊娠失败组体质指数、黄体生成素（LH）、LH/促卵泡生成素（FSH）、睾酮、抗苗勒管激素（AMH）、FAI、GnSAF高于妊娠成功组,FSH、受精率、优胚率、SHBG低于妊娠成功组（P＜0.05）。多因素Logistic回归分析显示,体质指数增加和LH、LH/FSH、AMH、FAI、GnSAF升高为PCOS不孕患者IVF-ET治疗妊娠失败的独立危险因素,SHBG升高为其独立保护因素（P＜0.05）。ROC曲线分析显示,FAI和血清GnSAF、SHBG联合预测PCOS不孕患者IVF-ET治疗妊娠结局的曲线下面积大于FAI、GnSAF、SHBG单独预测。结论：FAI和血清GnSAF、SHBG水平联合预测PCOS不孕患者IVF-ET治疗妊娠结局的价值较高。     

经鼻加温加湿高流量吸氧对重症肺炎伴呼吸衰竭患儿血气指标、肺功能及细胞因子水平的影响

摘要 目的：观察经鼻加温加湿高流量吸氧（HFNC）对重症肺炎伴呼吸衰竭患儿血气指标、肺功能及细胞因子水平的影响。方法：选取南京医科大学附属儿童医院2020年3月~2022年3月期间收治的86例重症肺炎伴呼吸衰竭患儿,按照随机数字表法分为经鼻持续气道正压通气（nCPAP）组和HFNC组,各为43例。对比两组临床相关指标、血气指标、肺功能及细胞因子水平,同时观察两组镇静剂使用、预后及并发症发生情况。结果：HFNC组的机械通气时间、咳嗽缓解时间、肺部啰音消失时间、入住儿童重症监护室（PICU）时间均短于nCPAP组（P<0.05）。两组患儿治疗后心率（HR）升高,呼吸频率（RR）下降,且HFNC组的变化大于nCPAP组（P<0.05）。两组患儿治疗后pH值、血氧分压（PO₂）、血氧饱和度（SpO₂）、氧合指数（OI）均升高,且HFNC组高于nCPAP组（P<0.05）。两组患儿治疗后用力肺活量（FVC）、1s用力呼气容积（FEV1）、用力呼气时最高呼气流速（PEF）升高,且HFNC组高于nCPAP组（P<0.05）。两组患儿治疗后降钙素原（PCT）、白细胞介素（IL-6）和肿瘤坏死因子（TNF-α）下降,且HFNC组低于nCPAP组（P<0.05）。HFNC组镇静剂使用、再住院例数均少于nCPAP组（P<0.05）。两组死亡例数、并发症发生率组间对比未见统计学差异（P>0.05）。结论：HFNC可有效缓解重症肺炎伴呼吸衰竭患儿的临床症状,改善血气指标、肺功能及细胞因子水平。     

Milk metabolites can characterise individual differences in animal resilience to a nutritional challenge in lactating dairy goats

The aim of this study is built in two phases: to quantify the ability of novel milk metabolites to measure between-animal variability in response and recovery profiles to a short-term nutritional challenge, then to derive a resilience index from the relationship between these individual variations. At two different stages of lactation, sixteen lactating dairy goats were exposed to a 2-d underfeeding challenge. The first challenge was in late lactation, and the second was carried out on the same goats early in the following lactation. During the entire experiment period, samples were taken at each milking for milk metabolite measures. For each metabolite, the response profile of each goat was characterised using a piecewise model for describing the dynamic pattern of response and recovery profiles after the challenge relative to the start of the nutritional challenge. Cluster Analysis identified three types of response/recovery profiles per metabolite. Using cluster membership, multiple correspondence analyses (MCAs) were performed to further characterise response profile types across animals and metabolites. This MCA analysis identified three groups of animals. Further, discriminant path analysis was able to separate these groups of multivariate response/recovery profile type based on threshold levels of three milk metabolites: β-hydroxybutyrate, free glucose and uric acid. Further analyses were done to explore the possibility of developing an index of resilience from milk metabolite measures. Different types of performance response to short-term nutritional challenge can be distinguished using multivariate analyses of a panel of milk metabolites.     

Use of Restored Small Wetlands by Breeding Waterfowl in Prince Edward Island, Canada

Abstract Since 1990 under the Eastern Habitat Joint Venture over 100 small wetlands have been restored in Prince Edward Island, Canada. Wetlands were restored by means of dredging accumulated sediment from erosion to emulate pre‐disturbance conditions (i.e., open water and extended hydroperiod). In 1998 and 1999 we compared waterfowl pair and brood use on 22 restored and 24 reference wetlands. More pairs and broods of Ring‐necked Ducks, Gadwall, Green‐winged Teal, and American Black Ducks used restored versus reference wetlands. In restored wetlands waterfowl pair density and species richness were positively correlated with wetland/cattail area, percent cattail cover, and close proximity to freshwater rivers. In addition, a waterfowl reproductive index was positively correlated with percent cattail cover. Green‐winged Teal pair occurrence in restored wetlands was positively correlated with greater amounts of open water and water depths. American Black Duck pairs occurred on most (86%) restored wetlands. Restored small wetlands likely served as stopover points for American Black Duck broods during overland or stream movements, whereas they likely served as a final brood‐rearing destination for Green‐winged Teal broods. We suggest that wetland restoration is a good management tool for increasing populations of Green‐winged Teal and American Black Ducks in Prince Edward Island.     

Birth Weight and Its Relationship to Size Attained and Relative Fat Distribution at 7 to 12 Years of Age

The relationship between birth weight and relative subcutaneous fat distribution at school age was considered in 131 boys and 106 girls 7 to 12 years of age. Relative fat distribution at school age was estimated with the ratio of the subscapular to triceps skinfolds (S/T) for the total sample, and with the ratio of the sum of two trunk (subscapular, midaxillary) to the sum of two extremity (triceps, medial calf) skinfolds (T/E) for subsamples of 102 boys and 63 girls. There were no sex differences in the S/T ratio (mm/mm), boys 0.62 ± 0.15, girls 0.63 ± 0.18; T/E ratio (mm/mm), boys 0.58 ± 0.13, girls 0.59 ± 0.16; and BMI (kg/m²), boys 17.1 ± 2.4, girls 16.9 ± 2.2. Second order partial correlations, controlling for age and the BMI or age and sum of skinfolds, between birth weight and the skinfold ratios are, respectively, ?0.22 and ?0.20 (p<0.01) for S/T and ?0.29 and ?032 (p<0.01) for T/E in girls, and ?0.18 and ?0.17 (p<0.05) for S/T and ?0.06 and ?0.6 for T/E in boys. Though low, the correlations suggest that as birth weight decreases proportionally more subcutaneous fat is accumulated on the trunk than on the extremities, more so in females than in males. Results of stepwise multiple regression analyses indicate that birth weight accounts for from 2% to 8% of the variance in relative subcutaneous fat distribution at school age.     

中国中部及北部地区奥陶系─三叠系的牙形刺色变指标（CAI）图

本文采用ＡｎｉｔａＨａｒｒｉｓ建立的统一标准,编制了中国中部和北部地区奥陶系─三叠系的１５幅牙形刺ＣＡＩ图,并作了说明,这对找油找气具有十分重要的意义。     

1H and 15N NMR resonance assignments and solution secondary structure of oxidized Desulfovibrio desulfuricans flavodoxin

Summary Sequence-specific ¹H and ¹⁵N resonance assignments have been made for 137 of the 146 nonprolyl residues in oxidized Desulfovibrio desulfuricans [Essex 6] flavodoxin. Assignments were obtained by a concerted analysis of the heteronuclear three-dimensional ¹H-¹⁵N NOESY-HMQC and TOCSY-HMQC data sets, recorded on uniformly ¹⁵N-enriched protein at 300 K. Numerous side-chain resonances have been partially or fully assigned. Residues with overlapping ¹H^N chemical shifts were resolved by a three-dimensional ¹H-¹⁵N HMQC-NOESY-HMQC spectrum. Medium-and long-range NOEs, ³J_NH coupling constants, and ¹H^N exchange data indicate a secondary structure consisting of five parallel -strands and four -helices with a topology similar to that of Desulfovibrio vulgaris [Hidenborough] flavodoxin. Prolines at positions 106 and 134, which are not conserved in D. vulgaris flavodoxin, contort the two C-terminal -helices.Abbreviations CSI chemical shift index - DQF-COSY double-quantum-filtered correlation spectroscopy - DIPSI decoupling in the presence of scalar interactions - FMN flavin mononucleotide - GARP globally optimized alternating phase rectangular pulse - HMQC heteronuclear multiple-quantum coherence - HSQC heteronuclear single-quantum coherence - NOE nuclear Overhauser effect - NOESY nuclear Overhauser enhancement spectroscopy - TOCSY total correlation spectroscopy - TPPI time-proportional phase increments - TSP 3-(trimethylsilyl)propionic-2,2,3,3-d ₄ acid, sodium salt     

杉木半同胞子代林的遗传测定和综合指数选择

本研究对四年生杉木半同胞子代林49个家系的遗传测定结果表明：树高、胸径、冠幅等性状呈高度遗传;枝粗、枝数等性状呈弱度遗传;枝数与大多性状间呈不显著遗传负相关;树高、胸径之间遗传相关显著;冠幅、年轮盘数、枝粗及枝长四者之间遗传相关极显著;该四性状与高、径之间呈极显著遗传相关．采用综合指数选择摸式得指数方程为I=1.647P1 2.993P2 1.522P3 0.086P4-0.ll7P5-1.779P6-1.995P7,据此选出遗传型最佳家系,并分析了综合指数选择法的合理性和有效性．     

System-level adjustments to elevated CO2 in model spruce ecosystems

Atmospheric carbon dioxide enrichment and increasing nitrogen deposition are often predicted to increase forest productivity based on currently available data for isolated forest tree seedlings or their leaves. However, it is highly uncertain whether such seedling responses will scale to the stand level. Therefore, we studied the effects of increasing CO₂ (280, 420 and 560 μL L^-1) and increasing rates of wet N deposition (0, 30 and 90 kg ha^-1 y^-1) on whole stands of 4-year-old spruce trees (Picea abies). One tree from each of six clones, together with two herbaceous understory species, were established in each of nine 0.7 m² model ecosystems in nutrient poor forest soil and grown in a simulated montane climate for two years. Shoot level light-saturated net photosynthesis measured at growth CO₂ concentrations increased with increasing CO₂, as well as with increasing N deposition. However, predawn shoot respiration was unaffected by treatments. When measured at a common CO₂ concentration of 420 μL L^-1 37% down-regulation of photosynthesis was observed in plants grown at 560 μL CO₂ L^-1. Length growth of shoots and stem diameter were not affected by CO₂ or N deposition. Bud burst was delayed, leaf area index (LAI) was lower, needle litter fall increased and soil CO₂ efflux increased with increasing CO₂. N deposition had no effect on these traits. At the ecosystem level the rate of net CO₂ exchange was not significantly different between CO₂ and N treatments. Most of the responses to CO₂ studied here were nonlinear with the most significant differences between 280 and 420 μL CO₂ L^-1 and relatively small changes between 420 and 560 μL CO₂ L^-1. Our results suggest that the lack of above-ground growth responses to elevated CO₂ is due to the combined effects of physiological down-regulation of photosynthesis at the leaf level, allometric adjustment at the canopy level (reduced LAI), and increasing strength of below-ground carbon sinks. The non-linearity of treatment effects further suggests that major responses of coniferous forests to atmospheric CO₂ enrichment might already be under way and that future responses may be comparatively smaller.