Tree-ring width(RW),density,elemental com-position,and stable carbon and oxygen isotope(δ^(13)C,δ^(18)O)are widely used as proxies to assess climate change,ecology,and environmental pollution;however,a specific pret...Tree-ring width(RW),density,elemental com-position,and stable carbon and oxygen isotope(δ^(13)C,δ^(18)O)are widely used as proxies to assess climate change,ecology,and environmental pollution;however,a specific pretreat-ment has been needed for each proxy.Here,we developed a method by which each proxy can be measured in the same sample.First,the sample is polished for ring width meas-urement.After obtaining the ring width data,the sample is cut to form a 1-mm-thick wood plate.The sample is then mounted in a vertical sample holder,and gradually scanned by an X-ray beam.Simultaneously,the count rates of the fluorescent photons of elements(for chemical characteriza-tion)and a radiographic grayscale image(for wood density)are obtained,i.e.the density and the element content are obtained.Then,cellulose is isolated from the 1-mm wood plate by removal of lignin,and hemicellulose.After producing this cellulose plate,cellulose subsamples are separated by knife under the microscope for inter-annual and intra-annual stable carbon and oxygen isotope(δ^(13)C,δ^(18)O)analysis.Based on this method,RW,density,elemental composition,δ^(13)C,and δ^(18)O can be measured from the same sample,which reduces sample amount and treatment time,and is helpful for multi-proxy comparison and combination research.展开更多
Using five well-replicated Qilian juniper (Sabina przewalskii Kom.) tree-ring width index se- ries, monthly normalized difference vegetation index (NDVI) of grassland, and climatic data from 1982 to 2001, the relation...Using five well-replicated Qilian juniper (Sabina przewalskii Kom.) tree-ring width index se- ries, monthly normalized difference vegetation index (NDVI) of grassland, and climatic data from 1982 to 2001, the relationships between tree-ring width index, NDVI of grassland, and climatic data were analyzed firstly. Then, the relationship between tree-ring width index and NDVI of grassland was explored. The re- sults showed that: (1) Temperature and precipitation in June influenced tree-ring width index and NDVI of grassland deeply in Delingha. (2) There were sig- nificant relationships between five tree-ring width index series (DLH1-DLH5) and monthly NDVI of grassland from June to September, with the most significant relationship being between tree-ring width index series and NDVI of grassland in August. (3) The PC1 (the first principal component derived from DLH1-DLH5 series) exhibited good agreement with monthly NDVI of grassland in the grass growth sea- son (from June to September) and the averaged NDVI in the growth season, which was attributed to their common responses to water-supply limit in Delingha. This study may allow an increase in studying the past dynamics of grassland in Delingha in that the variation of grassland NDVI during the last millennium has been reconstructed from PC1.展开更多
Tree-ring standardized chronologies are developed by 78 cores collected from the eastern and western Helan Mountain. Statistical analysis shows that both the STD and RES chronologies correlate negatively with the temp...Tree-ring standardized chronologies are developed by 78 cores collected from the eastern and western Helan Mountain. Statistical analysis shows that both the STD and RES chronologies correlate negatively with the temperature of different periods of early half year, especially with January to August mean （JA） temperature, which means that JA temperature is one of the predominant limiting factors of tree growth in the Helan Mountain. Based on this analysis, we reconstructed JA temperature, and the explained variance is 43.3% （F=21.422, p〈0.001 ）. The comparatively high temperature periods in the reconstruction were： 1805-1818 1828-1857, 1899-1907, 1919-1931 and 1968-1995; and the comparatively low temperatu re periods happened in 1858-1872, 1883-1895 and 1935-1953. Ten-year moving average curve shows three slow uplifting trends： 1766-1853, 1862-1931 and 1944-1995. Each temperature increase was followed by a sudden temperature decrease about 10 years, that is to say, the JA temperature in the Helan Mountain is characterized by slow increase and sudden decrease. The 70- and 10.77-year periodicities detected in the temperature series correspond to the Gleissberg （80-year） and Schwabe （11-year） periodicities of solar activity respectively, the 2.11-2.62 years cycles are considered to be influenced by QBO （Quasi-Biennial-Oscillation） and the local environmental change.展开更多
Based on the analysis of the correlation between the tree-ring width of Pinus tabulaeformis and the climate factors in the western Hedong sandy land of Ningxia, a conversion equation between the annual precipitation a...Based on the analysis of the correlation between the tree-ring width of Pinus tabulaeformis and the climate factors in the western Hedong sandy land of Ningxia, a conversion equation between the annual precipitation and the tree-ring width since 1899 was reconstructed. The results of cross verification indicated that the conversion equation is stable and the reconstructed results are reliable. The result of reconstructed annual precipitation showed the remarkable fluctuation of precipitation and dry-to-wet variation before the 1940s. The smaller fluctuation and high frequent changes of precipitation occurred during the period of 1940s-1980s and after the 1980s the change trend of the precipitation became high periodic extent and low frequent. The study found that there were some coincidences with the climate change in Changling Mountains, Helan Mountains and the east of Qilian Mountains. The relatively dry periods in the beginning of 20th century, 1920s to 1930s, the end of the 20th century and 2004 to 2006 in the western Hedong sandy land of Ningxia accelerated the desertification, while the relatively humid period during the periods of the 1910s-1920s, 1930s-1940s and 1990s is favorable to prevent and control the desertification, and to weaken the climate warming and drying. The periods of annual precipitation variation in the western Hedong sandy land of Ningxia since 1899 are approximately 2-4 years, 5-7 years and 10 years.展开更多
Regional tree-ring width chronology of the Scots pine (Pinus sylvestris L.) was constructed from 8 sites in the forest-steppe belt situated in the foothills of the Selenga River basin, Russia. Moisture information con...Regional tree-ring width chronology of the Scots pine (Pinus sylvestris L.) was constructed from 8 sites in the forest-steppe belt situated in the foothills of the Selenga River basin, Russia. Moisture information contained in tree-ring width chronology was obtained through linear regression reconstruction models of annual August–July precipitation and annual water discharge of the Selenga River during the period 1767–2015. Comparison of the smoothed series allowed estimating long-term variation component of these moisture regime parameters with a high precision. At the same time, regional drought indices are less correlated with pine radial growth, because they have contribution of the other environmental variables, which are much less reflected in the tree-ring of the investigated pine forest stands. Reconstructed dynamic of the moisture regime parameters is supported by documental evident of many socially significant events in the regional history, such as crop failures caused by both droughts and floods, and catastrophic fire in the Irkutsk City in 1879. Also, dependence of the amount of precipitation in the study area on the atmospheric circulation in Central Asia is revealed to have a similar pattern with other regions, i.e., a negative relationship of precipitation with the development of large high atmospheric pressure area within its center in the Altai and Tianshan mountains.展开更多
August-June precipitation has been reconstructed back to AD 1720 for the northern Greater Higgnan Mountains, China, by use ofPinus sylvestris var. mongolica tree-ring width. The reconstruction explains the variance of...August-June precipitation has been reconstructed back to AD 1720 for the northern Greater Higgnan Mountains, China, by use ofPinus sylvestris var. mongolica tree-ring width. The reconstruction explains the variance of 39% in observed precipitation from 1973 to 2008. Some extremely dry/wet signals in historical documents and other precipitation reconstructions in previous studies are precisely captured in our reconstruction. Wet periods occurred during the periods of 1730 to 1746, 1789 to 1812, 1844 to 1903, 1920 to 1930, 1942 to 1961, and 1985 to 1998; while periods of 1747 to 1788, 1813 to 1843, 1904 to 1919, 1931 to 1941, and 1962 to 1984 were relatively dry. Power spectral and wavelet analyses demon- strated the existence of significant 24-year, 12-year, and 2-year cycles of variability.展开更多
BACKGROUND The hemoglobin-to-red cell distribution width ratio(HRR)is a recently intro-duced,easily accessible marker that provides insights into inflammation and the tumor vascular microenvironment.It has been sugges...BACKGROUND The hemoglobin-to-red cell distribution width ratio(HRR)is a recently intro-duced,easily accessible marker that provides insights into inflammation and the tumor vascular microenvironment.It has been suggested to have prognostic value for overall survival in various types of cancer,including urothelial carcinoma,lung cancer,and hepatocellular carcinoma.It has not yet been sufficiently invest-igated in colorectal cancers(CRC).AIM To investigate the prognostic significance of the HRR and other inflammation-based hematological markers in patients with metastatic CRC.Additionally,the study evaluated the impact of surgical interventions,particularly metastasectomy,and multiple clinical and laboratory parameters on overall survival.By iden-tifying low-cost,accessible prognostic indicators,this research seeks to support clinicians in optimizing treatment strategies and risk stratification for patients with CRC.METHODS In this retrospective study,patients diagnosed with CRC between January 2020 and December 2024 were analyzed.The impact of HRR in conjunction with inflammatory markers and a total of 22 different clinical and laboratory para-meters on overall survival were evaluated using univariate Cox regression and a multivariate model.Survival curves were visualized using Kaplan-Meier analysis.RESULTS A total of 155 patients with CRC were included in the study.The median age was 60 years,and 61.9%presented with de novo metastasis.In the receiver operating characteristic curve and area under the curve analysis performed to determine the optimal cutoff,the values were found to be 6.10 for carcinoembryonic antigen(CEA)(P=0.036),18.85 for platelet-to-red cell distribution width ratio(P=0.028),and 10.87 for platelet distribution width-to-lymphocyte ratio(P=0.028).For neutrophil-to-lymphocyte ratio,systemic immune-inflammation index(SII),platelet-to-lymphocyte ratio(PLR),monocyte-to-lymphocyte ratio,HRR,and carbohydrate antigen 19-9,an optimal cutoff could not be determined using the receiver operating characteristic-area under the curve analysis.Therefore,the median values were adopted as the cutoffs(3.09,835.96,177.50,0.380,0.824,and 21.6,respectively).Univariate analysis identified male gender(P=0.045),being under 65 years of age(P=0.001),history of metastas-ectomy(P=0.001),low serum CEA level(P=0.010),low PLR(P=0.024),low SII(P=0.010),and high HRR(P=0.025)as favorable prognostic factors for overall survival.In the multivariate model,being under 65 years of age[hazard ratio(HR)=1.59,95%confidence interval(CI):1.06-2.39,P=0.025],metastasectomy(HR=0.49,95%CI:0.29-0.85,P=0.011),CEA(HR=1.51,95%CI:1.0-2.28,P=0.048),and PLR(HR=1.63,95%CI:1.09-2.44,P=0.018)emerged as independent prognostic factors for overall survival,whereas gender,SII,and HRR did not retain statistical significance.CONCLUSION In conclusion,low HRR alone was a prognostic indicator.However,when modelled with other inflammatory and clinical parameters,it did not provide a sufficiently strong marker feature.展开更多
AIM:To assess and compare the utility of neutrophil-to-lymphocyte ratio(NLR),platelet-to-lymphocyte ratio(PLR),systemic inflammation index(SII),and red blood cell distribution width(RDW)as potential biomarkers to pred...AIM:To assess and compare the utility of neutrophil-to-lymphocyte ratio(NLR),platelet-to-lymphocyte ratio(PLR),systemic inflammation index(SII),and red blood cell distribution width(RDW)as potential biomarkers to predict the severity of diabetic retinopathy(DR)in the United States population.METHODS:The observational study enlisted patients diagnosed with DR from the National Health and Nutrition Examination Survey(NHANES)database,spanning the period from 2005 to 2008.The severity of DR was defined according to Early Treatment for Diabetic Retinopathy Study(ETDRs).The effect of NLR,PLR,SII,and RDW on proliferative diabetic retinopathy(PDR)were explored using multivariable logistic regression analysis model.Subgroup analysis and restricted cubic splines(RCS)were conducted to assess the robustness of the correlations across subgroups and to explore nonlinear relationships between four indices and PDR.The receiver operating characteristic(ROC)analysis was employed for the purpose of assessing and evaluating the predictive efficacy of NLR,PLR,SII,and RDW in determining the severity of DR.RESULTS:After adjusting for other confounders(age,gender,race,body mass index,diabetes duration,and HbA1c)in multivariable analysis,a unit increase of PLR×0.1,SII×0.01,and RDW would raise the risk for PDR by 15.6%,22.2%,and 33%,respectively.Particularly,there was a 2.208-fold greater risk of PDR in individuals with an elevated NLR(OR=2.208,95%CI,1.348-3.617,P<0.001).RCS analyses showed positive relationships of four indices and PDR after segmented regression based on their own turning points.The results of ROC analysis revealed that PLR+RDW[area under the curve(AUC)=0.772,95%CI:0.669-0.874]had the best predictive value for PDR,compared with NLR+PLR+SII(AUC=0.697,95%CI:0.570-0.825)or RDW alone(AUC=0.736,95%CI:0.646-0.826).CONCLUSION:The combination of RDW and NLR demonstrates a promising ability to predict the severity of DR across the United States population,and it could be promisingly used in clinics for monitoring the progress of DR.展开更多
Reconstructing the hydrological change based on dendrohydrological data has important implications for understanding the dynamic distribution and evolution pattern of a given river. The widespread, long-living conifer...Reconstructing the hydrological change based on dendrohydrological data has important implications for understanding the dynamic distribution and evolution pattern of a given river. The widespread, long-living coniferous forests on the Altay Mountains provide a good example for carrying out the dendrohydrological studies. In this study, a regional composite tree-ring width chronology developed by Lariat sibirica Ledeb. and Picea obovata Ledeb. was used to reconstruct a 301-year annual （from preceding July to succeeding June） streamflow for the Haba River, which originates in the southern Altay Mountains, Xinjiang, China. Results indicated that the reconstructed streamflow series and the observations were fitting well, and explained 47.5% of the variation in the observed streamflow of 1957-2008. Moreover, floods and droughts in 1949-2000 were precisely captured by the streamflow reconstruction. Based on the frequencies of the wettest/driest years and decades, we identified the 19th century as the century with the largest occurrence of hydrological fluctuations for the last 300 years. After applying a 21-year moving average, we found five wet （1724-1758, 1780-1810, 1822-1853, 1931-1967, and 1986-2004） and four dry （1759-1779, 1811-1821, 1854-1930, and 1968-1985） periods in the streamflow reconstruction. Furthermore, four periods （1770-1796, 1816-1836, 1884-1949, and 1973-1997） identified by the streamflow series had an obvious increasing trend. The increasing trend of streamflow since the 1970s was the biggest in the last 300 years and coincided with the recent warming-wetting trend in northwestern China. A significant correlation between streamflow and precipitation in the Altay Mountains indicated that the streamflow reconstruction contained not only local, but also broad-scale, hydro-climatic signals. The 24-year, 12-year, and 2.2-4.5-year cycles of the reconstruction revealed that the streamflow variability of the Haba River may be influenced by solar activity and the atmosphere-ocean system.展开更多
Droughts are the most frequent natural disaster in regions at the margins of the East Asian summer monsoon(EASM),which pose threats to agriculture,the economy,and human lives.However,the limitations of only approximat...Droughts are the most frequent natural disaster in regions at the margins of the East Asian summer monsoon(EASM),which pose threats to agriculture,the economy,and human lives.However,the limitations of only approximately 60 years of meteorological observations hamper our understanding of the characteristics and mechanisms of local hydroclimate.Trees growing in the marginal region of the EASM are usually sensitive to moisture variations and have played important roles in past hydroclimatic reconstructions.Here,a 303-year tree-ring-width chronology of Pinus tabulaeformis from Mt.Lama,which is located in the junction of the Liaoning Province and Inner Mongolia,China,was used to reconstruct the May-August Palmer drought severity index(PDSI)in the marginal region of the EASM.The transfer function explains 48.0%(or 47.2%after adjusting for the loss of the degrees of freedom)of the variance over the calibration period from 1946 to 2012.A spatial correlation analysis demonstrates that our PDSI reconstruction can represent the drought variability on the northernmost margin of the EASM.The winter Asian polar vortex area index showed a delayed impact on the summer EASM precipitation in the following year.展开更多
Tree-ring width chronologies of Larix chinensis were developed from the northern and southern slopes of the Qinling Mountains in Shaanxi Province,and climatic factors affecting the tree-ring widths of L.chinensis were...Tree-ring width chronologies of Larix chinensis were developed from the northern and southern slopes of the Qinling Mountains in Shaanxi Province,and climatic factors affecting the tree-ring widths of L.chinensis were examined.Correlation analysis showed that similar correlations between tree-ring width chronologies and climatic factors demonstrated that radial growth responded to climate change on both slopes.The radial growth of L.chinensis was mainly limited by temperature,especially the growing season.In contrast,both chronologies were negatively correlated with precipitation in May of the previous year and April of the current year.Spatial climate-correlation analyses with gridded land-surface climate data revealed that our tree-ring width chronologies contained a strong regional temperature signal over much of northcentral and eastern China.Spatial correlation with seasurface temperature fields highlights the influence of the Pacific Ocean,Indian Ocean,and North Atlantic Ocean.Wavelet coherence analysis indicated the existence of some decadal and interannual cycles in the two tree-ring width chronologies.This may suggest the influences of El Nin˜o-Southern Oscillation and solar activity on tree growth in the Qinling Mountains.These findings will help us understand the growth response of L.chinensis to climate change in the Qinling region,and they provide critical information for future climate reconstructions based on this species in semi-humid regions.展开更多
The physiological response mechanisms of trees to climate change are complex,particularly across varying elevations and among different tree species.In this study,we collected tree ring samples from two dominant conif...The physiological response mechanisms of trees to climate change are complex,particularly across varying elevations and among different tree species.In this study,we collected tree ring samples from two dominant conifer species(Picea crassifolia and Pinus tabuliformis)at three elevations at the edge of the Tengger Desert.We used tree-ring width(TRW)and tree ring oxygen isotopes(δ^(18)O_(TR))to investigate how species and elevations affect their responses to climate change.Pearson’s correlation analysis and relative importance analysis were used to study the specific response processes of the two conifers to climate.The results showed that the TRW was mainly controlled by Standardized Precipitation Evapotranspiration Index(SPEI)during the growing season,which means that drought stress had the greatest effect on it.Andδ^(18)O_(TR)mainly responded to summer relative humidity.Both TRW andδ^(18)O_(TR)of P.crassifolia showed higher sensitivity to climate change.This sensitivity is largely attributed to the rapid uptake of precipitation by its developed shallow-rooted root system,which allows it to retain the precipitation signal in both TRW andδ^(18)O_(TR).However,P.crassifolia may be more susceptible to drought stress and growth decline or even death in the context of a warming region.Our results are important for understanding the impacts of climate change on forest ecosystems using multiple indicators and developing corresponding ecological conservation measures.展开更多
Recently, the general width-integral of index i was introduced and some of its isoperimetric inequalities were established. In this paper, we establish some new Brunn-Minkowski type inequalities for general width-inte...Recently, the general width-integral of index i was introduced and some of its isoperimetric inequalities were established. In this paper, we establish some new Brunn-Minkowski type inequalities for general width-integral of index i.展开更多
Droughts impact forests by influencing various processes such as canopy greenness,tree growth,and reproduction,but most studies have only examined a few of these processes.More comprehensive assessments of forest resp...Droughts impact forests by influencing various processes such as canopy greenness,tree growth,and reproduction,but most studies have only examined a few of these processes.More comprehensive assessments of forest responses to climate variability and water shortages are needed to improve forecasts of post-drought dynamics.Iberian forests are well-suited for evaluating these effects because they experience diverse climatic conditions and are dominated by various conifer and broadleaf species,many of which exhibit masting.We assessed how greenness,evaluated using the normalized difference vegetation index(NDVI),tree radial growth,and seed or cone production responded to drought in five tree species(three conifers:silver fir(Abies alba),Scots pine(Pinus sylvestris),and stone pine(Pinus pinea);two broadleaves:European beech(Fagus sylvatica)and holm oak(Quercus ilex)inhabiting sites with different aridity.We correlated these data with the standardized precipitation evapotranspiration index(SPEI)using the climate window analysis(climwin)package,which identifies the most relevant climate window.Drought constrained growth more than greenness and seed or cone production.Dry conditions led to high seed or cone production in species found in cool,moist sites(silver fir,beech,and Scots pine).We also found negative associations of cone production with summer SPEI in the drought-tolerant stone pine,which showed lagged growth-cone negative correlations.However,in the seasonally dry holm oak forests,severe droughts constrained both growth and acorn production,leading to a positive correlation between these variables.Drought impacts on greenness,growth,seed,and cone production depended on species phenology and site aridity.A negative correlation between growth and reproduction does not necessarily indicate trade-offs,as both may be influenced by similar climatic factors.展开更多
基金supported the National Natural Science Foundation of China (42022059,41888101)the Strategic Priority Research Program of the Chinese Academy of Sciences,China (Grant No.XDB26020000)+1 种基金the Key Research Program of the Institute of Geology and Geophysics (CAS Grant IGGCAS-201905)the CAS Youth Interdisciplinary Team (JCTD-2021-05).
文摘Tree-ring width(RW),density,elemental com-position,and stable carbon and oxygen isotope(δ^(13)C,δ^(18)O)are widely used as proxies to assess climate change,ecology,and environmental pollution;however,a specific pretreat-ment has been needed for each proxy.Here,we developed a method by which each proxy can be measured in the same sample.First,the sample is polished for ring width meas-urement.After obtaining the ring width data,the sample is cut to form a 1-mm-thick wood plate.The sample is then mounted in a vertical sample holder,and gradually scanned by an X-ray beam.Simultaneously,the count rates of the fluorescent photons of elements(for chemical characteriza-tion)and a radiographic grayscale image(for wood density)are obtained,i.e.the density and the element content are obtained.Then,cellulose is isolated from the 1-mm wood plate by removal of lignin,and hemicellulose.After producing this cellulose plate,cellulose subsamples are separated by knife under the microscope for inter-annual and intra-annual stable carbon and oxygen isotope(δ^(13)C,δ^(18)O)analysis.Based on this method,RW,density,elemental composition,δ^(13)C,and δ^(18)O can be measured from the same sample,which reduces sample amount and treatment time,and is helpful for multi-proxy comparison and combination research.
基金This work Was supported by the Key Program of the National Natural Science Foundation of China （Grant No. 40331006） the Key Project of Knowledge Innovation of the Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences （Grant No. CXI0G-E01-05 -02）.
文摘Using five well-replicated Qilian juniper (Sabina przewalskii Kom.) tree-ring width index se- ries, monthly normalized difference vegetation index (NDVI) of grassland, and climatic data from 1982 to 2001, the relationships between tree-ring width index, NDVI of grassland, and climatic data were analyzed firstly. Then, the relationship between tree-ring width index and NDVI of grassland was explored. The re- sults showed that: (1) Temperature and precipitation in June influenced tree-ring width index and NDVI of grassland deeply in Delingha. (2) There were sig- nificant relationships between five tree-ring width index series (DLH1-DLH5) and monthly NDVI of grassland from June to September, with the most significant relationship being between tree-ring width index series and NDVI of grassland in August. (3) The PC1 (the first principal component derived from DLH1-DLH5 series) exhibited good agreement with monthly NDVI of grassland in the grass growth sea- son (from June to September) and the averaged NDVI in the growth season, which was attributed to their common responses to water-supply limit in Delingha. This study may allow an increase in studying the past dynamics of grassland in Delingha in that the variation of grassland NDVI during the last millennium has been reconstructed from PC1.
基金National Natural Science Foundation of China, No.40525004 No.40599420+2 种基金 No.90211081 No.40531003 No.40121303
文摘Tree-ring standardized chronologies are developed by 78 cores collected from the eastern and western Helan Mountain. Statistical analysis shows that both the STD and RES chronologies correlate negatively with the temperature of different periods of early half year, especially with January to August mean （JA） temperature, which means that JA temperature is one of the predominant limiting factors of tree growth in the Helan Mountain. Based on this analysis, we reconstructed JA temperature, and the explained variance is 43.3% （F=21.422, p〈0.001 ）. The comparatively high temperature periods in the reconstruction were： 1805-1818 1828-1857, 1899-1907, 1919-1931 and 1968-1995; and the comparatively low temperatu re periods happened in 1858-1872, 1883-1895 and 1935-1953. Ten-year moving average curve shows three slow uplifting trends： 1766-1853, 1862-1931 and 1944-1995. Each temperature increase was followed by a sudden temperature decrease about 10 years, that is to say, the JA temperature in the Helan Mountain is characterized by slow increase and sudden decrease. The 70- and 10.77-year periodicities detected in the temperature series correspond to the Gleissberg （80-year） and Schwabe （11-year） periodicities of solar activity respectively, the 2.11-2.62 years cycles are considered to be influenced by QBO （Quasi-Biennial-Oscillation） and the local environmental change.
基金supported by the National Natural Science Foundation of China (40801004, 40671184)the Research Fund for the Doctoral Program of Higher Education (20070027019)
文摘Based on the analysis of the correlation between the tree-ring width of Pinus tabulaeformis and the climate factors in the western Hedong sandy land of Ningxia, a conversion equation between the annual precipitation and the tree-ring width since 1899 was reconstructed. The results of cross verification indicated that the conversion equation is stable and the reconstructed results are reliable. The result of reconstructed annual precipitation showed the remarkable fluctuation of precipitation and dry-to-wet variation before the 1940s. The smaller fluctuation and high frequent changes of precipitation occurred during the period of 1940s-1980s and after the 1980s the change trend of the precipitation became high periodic extent and low frequent. The study found that there were some coincidences with the climate change in Changling Mountains, Helan Mountains and the east of Qilian Mountains. The relatively dry periods in the beginning of 20th century, 1920s to 1930s, the end of the 20th century and 2004 to 2006 in the western Hedong sandy land of Ningxia accelerated the desertification, while the relatively humid period during the periods of the 1910s-1920s, 1930s-1940s and 1990s is favorable to prevent and control the desertification, and to weaken the climate warming and drying. The periods of annual precipitation variation in the western Hedong sandy land of Ningxia since 1899 are approximately 2-4 years, 5-7 years and 10 years.
基金funded by the Russian Foundation for Basic Research (17-04-00315)the Russian Science Foundation (14-14-00219)
文摘Regional tree-ring width chronology of the Scots pine (Pinus sylvestris L.) was constructed from 8 sites in the forest-steppe belt situated in the foothills of the Selenga River basin, Russia. Moisture information contained in tree-ring width chronology was obtained through linear regression reconstruction models of annual August–July precipitation and annual water discharge of the Selenga River during the period 1767–2015. Comparison of the smoothed series allowed estimating long-term variation component of these moisture regime parameters with a high precision. At the same time, regional drought indices are less correlated with pine radial growth, because they have contribution of the other environmental variables, which are much less reflected in the tree-ring of the investigated pine forest stands. Reconstructed dynamic of the moisture regime parameters is supported by documental evident of many socially significant events in the regional history, such as crop failures caused by both droughts and floods, and catastrophic fire in the Irkutsk City in 1879. Also, dependence of the amount of precipitation in the study area on the atmospheric circulation in Central Asia is revealed to have a similar pattern with other regions, i.e., a negative relationship of precipitation with the development of large high atmospheric pressure area within its center in the Altai and Tianshan mountains.
基金supported by the Climate Change Special Project of China Meteorological Administration (CCSF201438)the Meteorology Public Welfare Industry Research Special Project (GYHY201106013-3 and GYHY200806011)the Basic Research Operating Expenses of the Central-level Public Welfare Research Institutes (IDM201204)
文摘August-June precipitation has been reconstructed back to AD 1720 for the northern Greater Higgnan Mountains, China, by use ofPinus sylvestris var. mongolica tree-ring width. The reconstruction explains the variance of 39% in observed precipitation from 1973 to 2008. Some extremely dry/wet signals in historical documents and other precipitation reconstructions in previous studies are precisely captured in our reconstruction. Wet periods occurred during the periods of 1730 to 1746, 1789 to 1812, 1844 to 1903, 1920 to 1930, 1942 to 1961, and 1985 to 1998; while periods of 1747 to 1788, 1813 to 1843, 1904 to 1919, 1931 to 1941, and 1962 to 1984 were relatively dry. Power spectral and wavelet analyses demon- strated the existence of significant 24-year, 12-year, and 2-year cycles of variability.
文摘BACKGROUND The hemoglobin-to-red cell distribution width ratio(HRR)is a recently intro-duced,easily accessible marker that provides insights into inflammation and the tumor vascular microenvironment.It has been suggested to have prognostic value for overall survival in various types of cancer,including urothelial carcinoma,lung cancer,and hepatocellular carcinoma.It has not yet been sufficiently invest-igated in colorectal cancers(CRC).AIM To investigate the prognostic significance of the HRR and other inflammation-based hematological markers in patients with metastatic CRC.Additionally,the study evaluated the impact of surgical interventions,particularly metastasectomy,and multiple clinical and laboratory parameters on overall survival.By iden-tifying low-cost,accessible prognostic indicators,this research seeks to support clinicians in optimizing treatment strategies and risk stratification for patients with CRC.METHODS In this retrospective study,patients diagnosed with CRC between January 2020 and December 2024 were analyzed.The impact of HRR in conjunction with inflammatory markers and a total of 22 different clinical and laboratory para-meters on overall survival were evaluated using univariate Cox regression and a multivariate model.Survival curves were visualized using Kaplan-Meier analysis.RESULTS A total of 155 patients with CRC were included in the study.The median age was 60 years,and 61.9%presented with de novo metastasis.In the receiver operating characteristic curve and area under the curve analysis performed to determine the optimal cutoff,the values were found to be 6.10 for carcinoembryonic antigen(CEA)(P=0.036),18.85 for platelet-to-red cell distribution width ratio(P=0.028),and 10.87 for platelet distribution width-to-lymphocyte ratio(P=0.028).For neutrophil-to-lymphocyte ratio,systemic immune-inflammation index(SII),platelet-to-lymphocyte ratio(PLR),monocyte-to-lymphocyte ratio,HRR,and carbohydrate antigen 19-9,an optimal cutoff could not be determined using the receiver operating characteristic-area under the curve analysis.Therefore,the median values were adopted as the cutoffs(3.09,835.96,177.50,0.380,0.824,and 21.6,respectively).Univariate analysis identified male gender(P=0.045),being under 65 years of age(P=0.001),history of metastas-ectomy(P=0.001),low serum CEA level(P=0.010),low PLR(P=0.024),low SII(P=0.010),and high HRR(P=0.025)as favorable prognostic factors for overall survival.In the multivariate model,being under 65 years of age[hazard ratio(HR)=1.59,95%confidence interval(CI):1.06-2.39,P=0.025],metastasectomy(HR=0.49,95%CI:0.29-0.85,P=0.011),CEA(HR=1.51,95%CI:1.0-2.28,P=0.048),and PLR(HR=1.63,95%CI:1.09-2.44,P=0.018)emerged as independent prognostic factors for overall survival,whereas gender,SII,and HRR did not retain statistical significance.CONCLUSION In conclusion,low HRR alone was a prognostic indicator.However,when modelled with other inflammatory and clinical parameters,it did not provide a sufficiently strong marker feature.
基金Supported by Tianjin Natural Science Foundation(No.23JCZXJC00140).
文摘AIM:To assess and compare the utility of neutrophil-to-lymphocyte ratio(NLR),platelet-to-lymphocyte ratio(PLR),systemic inflammation index(SII),and red blood cell distribution width(RDW)as potential biomarkers to predict the severity of diabetic retinopathy(DR)in the United States population.METHODS:The observational study enlisted patients diagnosed with DR from the National Health and Nutrition Examination Survey(NHANES)database,spanning the period from 2005 to 2008.The severity of DR was defined according to Early Treatment for Diabetic Retinopathy Study(ETDRs).The effect of NLR,PLR,SII,and RDW on proliferative diabetic retinopathy(PDR)were explored using multivariable logistic regression analysis model.Subgroup analysis and restricted cubic splines(RCS)were conducted to assess the robustness of the correlations across subgroups and to explore nonlinear relationships between four indices and PDR.The receiver operating characteristic(ROC)analysis was employed for the purpose of assessing and evaluating the predictive efficacy of NLR,PLR,SII,and RDW in determining the severity of DR.RESULTS:After adjusting for other confounders(age,gender,race,body mass index,diabetes duration,and HbA1c)in multivariable analysis,a unit increase of PLR×0.1,SII×0.01,and RDW would raise the risk for PDR by 15.6%,22.2%,and 33%,respectively.Particularly,there was a 2.208-fold greater risk of PDR in individuals with an elevated NLR(OR=2.208,95%CI,1.348-3.617,P<0.001).RCS analyses showed positive relationships of four indices and PDR after segmented regression based on their own turning points.The results of ROC analysis revealed that PLR+RDW[area under the curve(AUC)=0.772,95%CI:0.669-0.874]had the best predictive value for PDR,compared with NLR+PLR+SII(AUC=0.697,95%CI:0.570-0.825)or RDW alone(AUC=0.736,95%CI:0.646-0.826).CONCLUSION:The combination of RDW and NLR demonstrates a promising ability to predict the severity of DR across the United States population,and it could be promisingly used in clinics for monitoring the progress of DR.
基金supported by the National Natural Science Foundation of China (41275120, 41605047)the Shanghai Cooperation Organization Science and Technology Partnership (2017E01032)+1 种基金the Special Foundation for Asian Regional Cooperation (Climate Reconstruction of Tian Shan in China, Kyrgyzstan and Tajikistan)the Autonomous Region Youth Science and Technology Innovation Talents Training Project (qn2015bs025)
文摘Reconstructing the hydrological change based on dendrohydrological data has important implications for understanding the dynamic distribution and evolution pattern of a given river. The widespread, long-living coniferous forests on the Altay Mountains provide a good example for carrying out the dendrohydrological studies. In this study, a regional composite tree-ring width chronology developed by Lariat sibirica Ledeb. and Picea obovata Ledeb. was used to reconstruct a 301-year annual （from preceding July to succeeding June） streamflow for the Haba River, which originates in the southern Altay Mountains, Xinjiang, China. Results indicated that the reconstructed streamflow series and the observations were fitting well, and explained 47.5% of the variation in the observed streamflow of 1957-2008. Moreover, floods and droughts in 1949-2000 were precisely captured by the streamflow reconstruction. Based on the frequencies of the wettest/driest years and decades, we identified the 19th century as the century with the largest occurrence of hydrological fluctuations for the last 300 years. After applying a 21-year moving average, we found five wet （1724-1758, 1780-1810, 1822-1853, 1931-1967, and 1986-2004） and four dry （1759-1779, 1811-1821, 1854-1930, and 1968-1985） periods in the streamflow reconstruction. Furthermore, four periods （1770-1796, 1816-1836, 1884-1949, and 1973-1997） identified by the streamflow series had an obvious increasing trend. The increasing trend of streamflow since the 1970s was the biggest in the last 300 years and coincided with the recent warming-wetting trend in northwestern China. A significant correlation between streamflow and precipitation in the Altay Mountains indicated that the streamflow reconstruction contained not only local, but also broad-scale, hydro-climatic signals. The 24-year, 12-year, and 2.2-4.5-year cycles of the reconstruction revealed that the streamflow variability of the Haba River may be influenced by solar activity and the atmosphere-ocean system.
基金The Strategic Priority Research Program of the Chinese Academy of Sciences,No.XDB40000000National Natural Science Foundation of China,No.41630531State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,CAS,No.SKLLQG2041。
文摘Droughts are the most frequent natural disaster in regions at the margins of the East Asian summer monsoon(EASM),which pose threats to agriculture,the economy,and human lives.However,the limitations of only approximately 60 years of meteorological observations hamper our understanding of the characteristics and mechanisms of local hydroclimate.Trees growing in the marginal region of the EASM are usually sensitive to moisture variations and have played important roles in past hydroclimatic reconstructions.Here,a 303-year tree-ring-width chronology of Pinus tabulaeformis from Mt.Lama,which is located in the junction of the Liaoning Province and Inner Mongolia,China,was used to reconstruct the May-August Palmer drought severity index(PDSI)in the marginal region of the EASM.The transfer function explains 48.0%(or 47.2%after adjusting for the loss of the degrees of freedom)of the variance over the calibration period from 1946 to 2012.A spatial correlation analysis demonstrates that our PDSI reconstruction can represent the drought variability on the northernmost margin of the EASM.The winter Asian polar vortex area index showed a delayed impact on the summer EASM precipitation in the following year.
基金funded by National Natural Science Foundation of China(No.31370587)
文摘Tree-ring width chronologies of Larix chinensis were developed from the northern and southern slopes of the Qinling Mountains in Shaanxi Province,and climatic factors affecting the tree-ring widths of L.chinensis were examined.Correlation analysis showed that similar correlations between tree-ring width chronologies and climatic factors demonstrated that radial growth responded to climate change on both slopes.The radial growth of L.chinensis was mainly limited by temperature,especially the growing season.In contrast,both chronologies were negatively correlated with precipitation in May of the previous year and April of the current year.Spatial climate-correlation analyses with gridded land-surface climate data revealed that our tree-ring width chronologies contained a strong regional temperature signal over much of northcentral and eastern China.Spatial correlation with seasurface temperature fields highlights the influence of the Pacific Ocean,Indian Ocean,and North Atlantic Ocean.Wavelet coherence analysis indicated the existence of some decadal and interannual cycles in the two tree-ring width chronologies.This may suggest the influences of El Nin˜o-Southern Oscillation and solar activity on tree growth in the Qinling Mountains.These findings will help us understand the growth response of L.chinensis to climate change in the Qinling region,and they provide critical information for future climate reconstructions based on this species in semi-humid regions.
基金supported by National Natural Science Foundation of China(no.42371038)Basic Research Innovation Group Project of Gansu Province(no.22JR5RA129)the 2022 Major Scientific Research Project Cultivation Plan of Northwest Normal University(NWNU-LKZD2022-04).
文摘The physiological response mechanisms of trees to climate change are complex,particularly across varying elevations and among different tree species.In this study,we collected tree ring samples from two dominant conifer species(Picea crassifolia and Pinus tabuliformis)at three elevations at the edge of the Tengger Desert.We used tree-ring width(TRW)and tree ring oxygen isotopes(δ^(18)O_(TR))to investigate how species and elevations affect their responses to climate change.Pearson’s correlation analysis and relative importance analysis were used to study the specific response processes of the two conifers to climate.The results showed that the TRW was mainly controlled by Standardized Precipitation Evapotranspiration Index(SPEI)during the growing season,which means that drought stress had the greatest effect on it.Andδ^(18)O_(TR)mainly responded to summer relative humidity.Both TRW andδ^(18)O_(TR)of P.crassifolia showed higher sensitivity to climate change.This sensitivity is largely attributed to the rapid uptake of precipitation by its developed shallow-rooted root system,which allows it to retain the precipitation signal in both TRW andδ^(18)O_(TR).However,P.crassifolia may be more susceptible to drought stress and growth decline or even death in the context of a warming region.Our results are important for understanding the impacts of climate change on forest ecosystems using multiple indicators and developing corresponding ecological conservation measures.
基金Supported by the Scientific Planning of Education of Gansu Province(GS[2017]GHBZ051)Introduction and Use of Open Online Courses of Gansu Province(2016-47)
文摘Recently, the general width-integral of index i was introduced and some of its isoperimetric inequalities were established. In this paper, we establish some new Brunn-Minkowski type inequalities for general width-integral of index i.
基金funded by the Science and Innovation Ministry of Spain(projects AGL 2012-33465,AGL 2016-76463-P,PID 2021-123675OB-C43,and TED 2021-129770B-C21)support by Margarita Salas postdoctoral fellowship(reference RCMS-22-G1T6IW-17-NLHJ80)of the Universidad Politécnica de Madrid
文摘Droughts impact forests by influencing various processes such as canopy greenness,tree growth,and reproduction,but most studies have only examined a few of these processes.More comprehensive assessments of forest responses to climate variability and water shortages are needed to improve forecasts of post-drought dynamics.Iberian forests are well-suited for evaluating these effects because they experience diverse climatic conditions and are dominated by various conifer and broadleaf species,many of which exhibit masting.We assessed how greenness,evaluated using the normalized difference vegetation index(NDVI),tree radial growth,and seed or cone production responded to drought in five tree species(three conifers:silver fir(Abies alba),Scots pine(Pinus sylvestris),and stone pine(Pinus pinea);two broadleaves:European beech(Fagus sylvatica)and holm oak(Quercus ilex)inhabiting sites with different aridity.We correlated these data with the standardized precipitation evapotranspiration index(SPEI)using the climate window analysis(climwin)package,which identifies the most relevant climate window.Drought constrained growth more than greenness and seed or cone production.Dry conditions led to high seed or cone production in species found in cool,moist sites(silver fir,beech,and Scots pine).We also found negative associations of cone production with summer SPEI in the drought-tolerant stone pine,which showed lagged growth-cone negative correlations.However,in the seasonally dry holm oak forests,severe droughts constrained both growth and acorn production,leading to a positive correlation between these variables.Drought impacts on greenness,growth,seed,and cone production depended on species phenology and site aridity.A negative correlation between growth and reproduction does not necessarily indicate trade-offs,as both may be influenced by similar climatic factors.
