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Spatial and temporal patterns of forest fires in the Central Monte:relationships with regional climate

Ecological Processes 2024年第1期13卷 66-79页

作者： Pablo Eugenio Villagra Erica Cesca Leandro Manuel Alvarez Silvia delgado Ricardo Villalba Instituto Argentino de Nivología Glaciología y ciencias Ambientales–CONICET-CCT Mendoza Facultad de ciencias Agrarias Universidad Nacional de Cuyo

Background Natural and anthropogenic wildfires burn large areas of arid and semi-arid forests with significant socio-economic and environmental impacts. Fire regimes are controlled by climate, vegetation type, and anthropogenic factors such as ignition sources and human-induced disturbances. Projections of climate and land-use change suggest that these controlling factors will change, altering fire regimes in the near future. In the southern Central Monte, Mendoza, Argentina, the factors that modulate the fire temporal and spatial variability are poorly understood. We reconstructed the fire history of southeast of Mendoza from 1984 to 2023 and investigated the relationships between fire extent and climate variability at seasonal and interannual scales. Burned areas were determined using Google Earth Engine by processing Landsat 5-TM, Landsat 7-ETM+, and Landsat 8-OLI-TIRS sensor *** The region exhibited high spatial and temporal variability in fire occurrence, being a mosaic of areas with different fire histories and recovery times. Between 1985 and 2023, fire recurrence ranged from sites unburned to sites with up to 14 fires. The occurrence of large fires was strongly favored by a combination of a year with abundant spring–early summer precipitation, which favors fuel accumulation, followed by a year of low spring–early summer precipitation. Precipitation and burnt area showed a very pronounced 6–7 year cycle, suggesting a dominant climatic control on fire *** Fire distribution in southeastern Mendoza forests is not homogeneous, resulting in a mosaic of patches with different fire histories. This heterogeneity may be related to vegetation patterns and land use. The temporal variability of fires is strongly influenced by climate variability, which would promote fuel production and subsequent drying. Large fires are concentrated in periods of high interannual precipitation variability. Climate change scenarios predict an increase in tem

关键词： Fire recurrence Fire mapping Recovery time Climate Dry forest Wildfire

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Solitary Potential in a Space Plasma Containing Dynamical Heavy Ions and Bi-Kappa Distributed Electrons of Two Distinct Temperatures

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Communications in Theoretical Physics 2018年第1期69卷 107-114页

作者： M.Sarker B.Hosen M.R.Hossen A.A.Mamun department of Physics Jahangirnagar University department of General Educational development Daffodil International University

The heavy ion-acoustic solitary waves(HIASWs) in a magnetized, collisionless, space plasma system(containing dynamical heavy ions and bi-kappa distributed electrons of two distinct temperatures) have been theoretically investigated. The Korteweg-de Vries(K-dV), modified K-dV(MK-dV), and higher-order MK-dV(HMK-dV) equations are derived by employing the reductive perturbation method. The basic features of HIASWs(viz. speed, polarity,amplitude, width, etc.) are found to be significantly modified by the effects of number density and temperature of different plasma species, and external magnetic field(obliqueness). The K-dV and HM-Kd V equations give rise to both compressive and rarefactive solitary structures, whereas the MK-dV equation supports only the compressive solitary structures. The implication of our results in some space and laboratory plasma situations are briefly discussed.

关键词： heavy ion acoustic waves solitary waves superthermal electrons higher order nonlinear equations

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Radiative forcing due to dust aerosol over east Asia-north Pacific region during spring, 2001

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Chinese Science Bulletin 2004年第20期49卷 2212-2219页

作者： WANGHong SHIGuangyu AokiTeruo WANGBiao ZHAOTianliang StateKeyLaboratoryofNumericalModelingforAtmosphericSciencesandGeophysicalFluidDynamics.InstituteofAtmosphericPhysics.ChineseAcademyofSciences Beijing100029China MeteorologicalResearchInstitute 1-1NagamineTsukubaIbaraki305-0052.Japan AirQualityResearchBranch MeteorologicalServiceofCanada.TorontoOntarioCanada

An optical model accounting for the East Asian dust is proposed as a result of theory calculation and compo-sition analysis of the aerosol samples collected in China de-sert during the international project, Studies on the Origin and Transport of Aeolian Dust and its Effects on Climate (AdeC). Study indicates that dust aerosols emitting from China deserts have smaller imaginary parts of refractive indices, therefore absorb less and scatter more solar radia-tion than the most dust optical models published so far. Fur-thermore, the forward fraction of scattering is less and the backscattering is stronger than those of the other models. The seasonal averaged radiative forcing in spring, 2001 over east Asia-north Pacific region is simulated employing the new dust optical model. The net forcing at the top of atmos-phere (TOA) is estimated as -0.943 W·m-2 for regional and seasonal mean, with shortwave and longwave contributions of -1.700 and 0.759 W·m-2, respectively. The surface net forcing is calculated to be -5.445 W·m-2, and made up of shortwave component of -6.250 W·m-2 and longwave component of +0.759 W·m-2. The distributions of TOA and surface net forcing over this region are also analyzed in this study.

关键词：辐射强度灰尘浮质东亚-北太平洋地区折射率辐射表征大气烟雾大气污染

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Influence of the gravity on interface shape during crystal growth of LICAF

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Science China Mathematics 2000年第4期43卷 430-438页

作者：刘永才陈万春 Institute of Physics Chinese Academy of Sciences Beijing 100080 China School of Chemical Engineering Tianjin University Tianjin 300072 China Institute of Physics Chinese Academy of Sciences Beijing 100080 China National Laboratory of Microgravity Chinese Academy of Sciences Beijing 100080 China

A Galerkin finite element method, together with the boundary conformal mapping technique, is used to investigate the change of melWcrystal interface under low gravity during the growth of LEAF system. Results have shown that strong convection can cause a deeply concave interface toward the crystal, and significantly increase radial thermal gradients near the interface. The flow intensity and the change of the gravity have a linear relationship under low gravity (g o u = 10?2-10?6). At smallMa number, the maximum acceleration for keeping a planar growth interface is gmax = 1 × 10?3 g under our given conditions. In addition, the growth velocity may have some influence on the growth interface shape even atpg gravity level, indicating that the growth velocity cannot be too fast even when convection is very weak.

关键词： finite element method convection horizontal Bridgman melt/crystal interface.

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A functional variant in the CD209 promoter is associated with DQ2-negative celiac disease in the Spanish population

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World Journal of Gastroenterology 2006年第27期12卷 4397-4400页

作者： C Nú■ez B Rueda A Martínez C Maluenda I Polanco MA López-Nevot E Ortega E Sierra E Gómez de la Concha E Urcelay J Martín Servicio de Inmunología Clínica Hospital Clínico San CarlosMadridSpain Instituto de Parasitología y Biomedicina "López Neyra" CSICGranadaSpain Servicio de Pediatría Hospital Clínico San CarlosMadrid Spain Servicio de Gastroenterología y Nutrición Pediátrica Hospital La PazMadridSpain Servicio de Inmunología Hospital Virgen de las NievesGranadaSpain Servicio de Pediatría Hospital Virgen de las NievesGranadaSpain Centro de Investigaciones Biológicas CISCMadridSpain

AIM： To address the role of CD209 in celiac disease （CD） patients. Non-human leukocyte antigen （HLA） genetic factors in CD predisposition are poorly understood, and environmental factors like infectious pathogens may play a role. CD209 is a dendritic and macrophage surface molecule involved in pathogen recognition and immune activation. Recently, a functional variant in the promoter of the CD209 gene （-336A/G） has been shown to affect the transcriptional CD209 activity in vitro and it has been associated with a higher susceptibility to/or severity of infection. METHODS： The study population was composed of two case-control cohorts of 103 and 386 CD patients and 312 y 419 healthy controls as well as a panel of 257 celiac families. Genotyping for the -336A/G CD209 promoter polymorphism was performed using a TaqMan 5＇ allelic discrimination assay. HLA-DQ was determined by hybridization with allele specific probes. RESULTS： Initially, the case-control and familial studies did not find any association of the -336 A/G CD209 genetic variant with CD susceptibility. However, the stratification by HLA-DQ2 did reveal a significant association of CD209 promoter polymorphism in the HLA-DQ2 （-） group （carrier A vs GG in DQ2 （-） vs DQ2 （＋） patients （P = 0.026, OR = 3.71）. CONCLUSION： The -336G CD209 allele seems to be involved in CD susceptibility in HLA-DQ2 （-） patients. Our results might suggest a possible role of pathogens in the onset of a minor group of CD patients.

关键词： CD209 HLA-DQ2 Celiac disease Single nucleotide polymorphism Susceptibility

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Two new limonoids from Melia toosendan

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Chinese Chemical Letters 2008年第2期19卷 183-186页

作者： Fan Xie Chao Feng Zhang Mian Zhang Zheng Tao Wang Bo yang yu Key Laboratory of Modern Chinese Medicines （China Pharmaceutical University） Ministry of Education Nanjing 210038 PR China Research department of Pharmacognosy China Pharmaceutical University Nanjing 210038 PR China

Two new limonoid-type triterpenoids, named 12-o-ethyl-l-deacetylnimbolinin B and 1-o-tigloyl-1-o-debenzoylohchinal, have been isolated from the fruit of Melia toosendan Sieb. et Zucc. Their structures were elucidated ... 详细信息

关键词： Melia toosendan Limonoids 12-o-Ethyl-1-deacetylnimbolinin B 1-o-Tigloyl-1-o-debenzoylohchinal

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Sperm kinematic, head morphometric and kinetic- morphometric subpopulations in the blue fox （Alopex lagopus）

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Asian Journal of Andrology 2017年第2期19卷 154-159页

作者： Caries Soler Jesus Contell Lorena Bori Maria Sancho Almudena Garcia-Molina Anthony Valverde Jan Segarvall department of Functional Biology and Physical Anthropology University of Valencia 46100 Burjassot Spain R+D department Proiser R+D Scientific Park University of Valencia 46980 Paterna Spain Technological Institute of Costa Rica San Carlos Campus School of Agronomy 223-21001 Alajuela Costa Rica Finnish Fur Breeders Association ProFur 65101 Vaasa Finland

This work provides information on the blue fox ejaculated sperm quality needed for seminal dose calculations. Twenty semen samples, obtained by masturbation, were analyzed for kinematic and morphometric parameters by using CASA-Mot and CASA-Morph system and principal component （PC） analysis. For motility, eight kinematic parameters were evaluated, which were reduced to PC1, related to linear variables, and PC2, related to oscillatory movement. The whole population was divided into three independent subpopulations： SP1, fast cells with linear movement; SP2, slow cells and nonoscillatory motility; and SP3, medium speed cells and oscillatory movement. In almost all cases, the subpopulation distribution by animal was significantly different. Head morphology analysis generated four size and four shape parameters, which were reduced to PC 1, related to size, and PC2, related to shape of the cells. Three morphometric subpopulations existed. SPI： large oval cells; SP2： medium size elongated cells; and SP3. small and short cells. The subpopulation distribution differed between animals. Combining the kinematic and morphometric datasets produced PC1, related to morphometric parameters, and PC2, related to kinematics, which generated four sperm subpopulations - SPI.. high oscillatory motility, large and short heads; SP2; medium velocity with small and short heads; SP3. slow motion small and elongated cells; and SP4. high linear speed and large elongated cells. Subpopulation distribution was different in all animals. The establishment of sperm subpopulations from kinematic, morphometric, and combined variables not only improves the well-defined fox semen characteristics and offers a good conceptual basis for fertility and sperm preservation techniques in this species, but also opens the door to use this approach in other species, included humans.

关键词： integration of motility and morphology principal component analysis sperm morphometry subpopulation

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Analysis of carbon isotopes in airborne carbonate and impli-cations for aeolian sources

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Chinese Science Bulletin 2004年第15期49卷 1637-1641页

作者： CAOJunji WANGyaqiang ZHANGXiaoye Leeshuncheng HoKinfai CAOyunning LIyang SKLLQG InstituteofEarthEnvironmentChineseAcademyofSciencesXi'an710075China departmentofCivilandStructuralEngineering TheHongKongPolytechnicUniversityHongKongChina

Methods were developed to determine the mass ratios of carbon isotopes in trace amounts of aerosol carbon- ate. A Finnigan MAT 252 mass spectrometer fitted with an on-line Kiel device was to determine the C/12C ratio in CO2 13 produced from the carbonate. A study using these methods was conducted to characterize the carbonate carbon isotopes in aerosol samples collected in Xi’an on dusty and normal days during March and April 2002. Results of the study demonstrate that insights into the origin of the dust can be deduced from its isotopic composition. That is, the δ C of 13 carbonate for dust storm samples ranged from ?1.4‰ to ?4.2‰, and this is consistent with sandy materials in dust source regions upwind. In contrast, for non-dusty days δ13C ranged from ?7.5% to ?9.3‰, which is more similar to fine particles emitted from local surface soils. Comparisons of dust storm aerosols with surface soils from source regions and with aerosol samples collected downwind indicate that the δ C values did not change appreciably during long- 13 range transport. Therefore, carbon isotopes have the poten- tial for distinguishing among source materials, and this ap- proach provides a powerful new tool for identifying dust provenance.

关键词：碳同位素气溶胶碳酸盐沙尘起源大气化学

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Luminal oxidants selectively modulate electrogenic ion transport in rat colon

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World Journal of Gastroenterology 2006年第34期12卷 5523-5527页

作者： Julio M Mayol yolanda Adame-Navarrete Pilar Alarma-Estrany Elena Molina-Roldan Fernando Huete-Toral Jesus A Fernandez-Represa Servicio de Cirugia I Hospital Clinico San Carlos Universidad Complutense De Madrid Madrid 28040 Spain

AIM： To investigate the effects of luminal exposure to H2O2 and two related thiol oxidizing agents on basal and stimulated chloride secretion in native colon using electrophysiological and pharmacological approaches. METHODS： Unstripped rat distal colon segments were mounted in Ussing chambers. Potential difference, calculated resistance and short-circuit current across unstripped colon segments were monitored with a dual voltage/current clamp. Paracellular permeability was assessed by measuring the mucosa-to-serosa flux of a fluorescent probe （FITC）. RESULTS： Luminal exposure to hydrogen peroxide transitorily stimulated chloride secretion without altering barrier function. This stimulatory effect could be blocked by basolateral atropine but not indomethacin. The cysteine and methionine oxidizing compounds, phenylarsine oxide and chloramine T respectively, mimicked the effect of H2O2, except for a drop in transcolonic resistance after 30 min. In contrast to the observed stimulatory effect on basal secretion, cAMP-stimulated electrogenic ion transport was blunted by luminal H2O2. However, the Ca^2＋- activated response remained unchanged. CONCLUSION： H2O2 may be an important selective modulator of intestinal ion and water secretion in certain pathologic conditions such as inflammation or ischemiareperfusion by multiple mechanisms.

关键词： Chloride secretion Ion transport Rat distal colon Hydrogen peroxide Acetylcholine Atropine

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The diversity of denitrifying bacteria in the alpine meadow soil of Sanjiangyuan natural reserve in Tibet Plateau

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Chinese Science Bulletin 2006年第10期51卷 1245-1254页

作者： ZHANG yuguang LI Diqiang WANG Huimin XIAO Qiming LIU Xueduan Institute of Forestry Ecology Environment and Protection Chinese Academy of Forestry the Key Laboratory of Forest Ecology and En- vironment of State Forestry Administration Beijing 100091 China College of Biosafety Science and Technology Hunan Agricultural University Changsha 410128 China

This is the first time to describe the diversity of denitrifying bacteria in Sanjiangyuan natural reserve in Tibet Plateau by investigating the molecular diversity and phylogenetic analysis of nirK and nosZ genes using PCR-RFLP and sequencing. Four soil samples were collected from alpine meadow communities from over an altitude of 4600 m which had different physicochemical properties by principal component analysis (PCA). For the genes fragment of nirK and nosZ, the diverse PCR products were characterized by cloning, restriction fragment length polymorphism (RFLP) analysis and sequenced. A total of 253 nirK clones and 283 nosZ clones were received in four samples, and 78 operational taxonomic units (OTUs) of nirK and 120 OTUs of nosZ by the restriction enzymes MspI and RsaI digested. The analysis of environmental factors showed that altitude and C/N ratio in soil may be the key factors to the denitrifying bacteria community. 36 nirK clones and 17 nosZ clones were sequenced, and their levels of nucleotide identity were from 69% to 98% and 57% to 97%, respectively. The phylogenetic tree was constructed using the Clustal W and Mega softwares, and all the sequenced clones could be subdivided into 4 groups. Some of clone sequences were related to the nirK and nosZ genes belonging to three phylogenetic subdivisions (α-, β- and γ subclasses of the Proteobacteria), while most of the clones were closely related to the genes of the uncultured bacteria. The sequence distributions were not clear relating to the sample sites in the tree.

关键词：高山草甸脱氮细菌多样性土壤三江源自然保护区西藏高原

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