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1.
Neil J. Tabor Roger M.H. Smith J. Sébastien Steyer Christian A. Sidor Christopher J. Poulsen 《Palaeogeography, Palaeoclimatology, Palaeoecology》2011,299(1-2):200-213
Three basic paleosol morphologies, named Type A, Type B and Type C, are described from the middle–upper Permian strata of the Moradi Formation, Tim Mersoi Basin, northern Niger. The Moradi Formation is a typical alluvial redbed succession dominated by red mudrocks with fine to coarse-grained pebbly channel sandstones and matrix-breccias. Type A paleosols are hosted by well-sorted fine to medium grained trough cross bedded and massive sandstones and preserve abundant vertical to horizontal micritic and microspar calcite tubules, interpreted as rhizoliths. Lateral variability of rhizoliths in Type A paleosols, and their close association with fluvial channel-fill sediments suggests they are the roots of grove stands of phreatophytic vegetation that grew within unstable anabranching stream systems. Type B paleosols are hosted by mudrocks and preserve well-developed ped structure, abundant micritic calcite nodules and vertically-stacked micritic calcite nodular bodies, as well as rare calcite with satin-spar texture interpreted as a pseudomorphic replacement of pedogenic gypsum. The morphology of Type B paleosols suggests they were formed in well-drained floodplain deposits on stable landforms. Type C paleosols are similar to Type B but preserve pedogenic structures indicative of soil volume expansion and contraction, as well as more abundant Stage II pedogenic carbonate nodules. The morphology of Type C paleosols suggests that they developed periodically rather than seasonally in poorly-drained deposits that nevertheless occupied a relatively stable part of the landscape such as the plains flanking ephemeral lakes or sabkhas.X-ray diffraction analysis of the < 2 μm fraction from the Moradi Formation strata indicates that paleosol phyllosilicates are composed of illite, smectite, and occasionally kaolinite and talc. Illite is likely a detrital mineral, whereas smectite and kaolinite are likely pedogenic weathering products. The presence of talc in the Moradi Formation paleosols is unusual. It is limited to paleosol horizons that also preserve evidence for pedogenic gypsum accumulation and is therefore most likely related to a pedogenic weathering process. It is possible that this talc is a relatively low-temperature (~ 50–100 °C) diagenetic alteration product of pedogenic Mg–phyllosilicates such as sepiolite.The range of morphologies, petrographic textures and mineralogy of the paleosol profiles indicates semi-arid to hyper-arid climatic setting. This paleoclimatic reconstruction is in agreement with Middle and Late Permian conceptual paleoclimate models and quantitative general circulation models. Nevertheless, and in spite of an arid climate, Moradi paleosols and their host strata also indicate a relatively shallow groundwater table. Importantly, this shallow groundwater resource undoubtedly helped to support the moderately diverse fossil vertebrate assemblage and large-stature macrophytes preserved in the Moradi Formation. 相似文献
2.
Giovanni Muttoni Dennis V. Kent Flavio Jadoul Paul E. Olsen Manuel Rigo Maria Teresa Galli Alda Nicora 《Palaeogeography, Palaeoclimatology, Palaeoecology》2010,285(1-2):1-16
New Late Triassic–earliest Jurassic magneto-biostratigraphic data have been obtained from three overlapping sections in the Southern Alps, Italy (Costa Imagna, Brumano, Italcementi Quarry), composed of ~ 520 m of shallow-marine carbonates outcropping in stratigraphic continuity. Characteristic magnetic components of presumed depositional age record a sequence of 9 normal and reverse polarity magnetozones (as defined by at least three stratigraphically superposed samples) linked by conodont and palynofloral evidence from this study and the literature to Rhaetian to Triassic–Jurassic boundary age. This represents a significantly larger number of polarity zones than previously recognized in more condensed Rhaetian sections from the literature, and by inference represents more time. These data are placed in a broader Late Triassic temporal framework by means of correlations to published magneto-biostratigraphic data from the Tethyan marine Pizzo Mondello section and the Newark astronomical polarity time scale (APTS). This framework is consistent with a position of the Norian–Rhaetian boundary (as defined at Brumano and Pizzo Mondello by the first appearance of Misikella posthernsteini) within Newark magnetozones E17r–E19r in the ~ 207–210 Ma time interval, in basic agreement with the position originally estimated in the Newark using pollen biostratigraphy (E18 at 208–209 Ma). This framework is also consistent with the position of the Triassic–Jurassic boundary interval (placed at Italcementi Quarry at the acme of Kraeuselisporites reissingeri coincident with a negative carbon isotope excursion) correlative to just above Newark magnetozone E23r and just below the oldest CAMP lavas dated at ~ 202 Ma. Hence, we estimate the duration of the Rhaetian to be ~ 5.5–8.5 Myr (or even longer if the Triassic–Jurassic boundary is instead placed above the negative carbon isotope excursion as at Kuhjoch, which is the designated GSSP for the base of the Hettangian), and encompassing 9 magnetozones. This duration contrasts with a duration of ~ 2 Myr and only ~ 4 magnetozones in several alternative published magneto-biostratigraphic schemes. 相似文献
3.
《Palaeoworld》2020,29(2):405-425
The Urzhumian (Wordian) and Severodvinian (Capitanian) reference section of the Monastery Ravine (Kazan Volga region, Russia), contains two siltstone lithofacies: (a) laminated and (b) massive. Depositional settings of the laminated siltstones can be interpreted as perennial to ephemeral lakes; depositional settings of the massive siltstones are interpreted as floodplains with soil cover and periodical silt influx in wet seasons. The bulk geochemistry of siliciclastics has revealed a high degree of weathering of both types of siltstone. The similar chemical composition, mineralogy, and grain size suggest the same provenance of silt material. Geochemical data indicate eastern source rocks, which are the Permian red beds of the Cis-Ural plains.The main genetic types of paleosols hosted in the massive siltstones in the studied section, include moderately developed Vertisols and Calcisols with drab-colored root traces, calcareous nodules, low chroma mottles, angular blocky peds and slickensides. These pedofeatures indicate in general a semi-arid climate with clear seasonality of rainfall. Major oxides of the paleosol matrix were used to estimate paleoprecipitation through the bases to alumina (ΣBases/Al) ratio and chemical index of alteration minus potassium (CIA-K) proxies. Estimates from Urzhumian paleosols indicate relatively low mean annual precipitation (MAP) of 390 mm/yr. The transition to the Severodvinian paleosols is marked by a noticeable MAP increase up to 777 mm/yr. This climate moistening coincides with changes in the morphology of paleosols from dolomitic with low redoximorphy to calcitic with gley horizons. The pedogenic carbonate nodules consisting of dolomicrite (5–10 μm) are very common in the Urzhumian paleosols and their morphology, micromorhology and isotopic features indicate the pedogenic origin of dolomite.Sedimentological and paleopedological features of the studied siltstones, as well as the location of the Volga-Ural basin in a mid-latitude position (25–32 °N) indicate a monsoonal character of precipitation during the Middle Permian. 相似文献
4.
Gregory J. Retallack Chengmin Huang 《Palaeogeography, Palaeoclimatology, Palaeoecology》2011,299(1-2):110-128
The first trees in New York were Middle Devonian (earliest Givetian) cladoxyls (?Duisbergia and Wattieza), with shallow-rooted manoxylic trunks. Cladoxyl trees in New York thus postdate their latest Emsian evolution in Spitzbergen. Progymnosperm trees (?Svalbardia and Callixylon–Archaeopteris) appeared in New York later (mid-Givetian) than progymnosperm trees from Spitzbergen (early Givetian). Associated paleosols are evidence that Wattieza formed intertidal to estuarine mangal and Callixylon formed dry riparian woodland. Also from paleosols comes evidence that Wattieza and Callixylon required about 350 mm more mean annual precipitation than plants of equivalent stature today, that Wattieza tolerated mean annual temperature 7 °C less than current limits of mangal (20 °C), and Callixylon could tolerate temperatures 14 °C less than modern mangal. Devonian mangal and riparian woodland spread into New York from wetter regions elsewhere during transient paleoclimatic spikes of very high CO2 (3923 ± 238 ppmv), and subhumid (mean annual precipitation 730 ± 147 mm) conditions, which were more likely extrinsic atmospheric perturbations rather than consequences of tree evolution. For most of the Middle Devonian CO2 was lower (2263 ± 238 ppmv), and paleoclimate in New York was semiarid (mean annual precipitation 484 ± 147 mm). Such transient perturbations and immigration events may explain the 40 million year gap between the late Emsian (400 Ma) evolution of trees and Famennian (360 Ma) CO2 drawdown and expansion of ice caps. 相似文献
5.
《Comptes Rendus Palevol》2008,7(5):259-268
Pennsylvanian carbonates are widespread in Sonora (Mexico) and contain a diverse biota of foraminifers and calcareous algae. Detailed studies here are devoted to the outcrops of the Sierra Agua Verde and Cerro El Tule. The Late Atokan (early Late Moscovian part), Desmoinesian (= late Late Moscovian) and Missourian (= Kasimovian) stages are especially rich in fusulinids and algae. The principal zones of fusulinids of Wilde encountered are A3, DS1 and MC1–2. New data are given about the genera Fusulinella, Parawedekindellina, Zellerella, Komia and Paraepimastopora, in order to establish migrations or vicariances between Mexico and Palaeotethys. 相似文献
6.
Lydia S. Tackett Alan J. Kaufman Frank A. Corsetti David J. Bottjer 《Lethaia: An International Journal of Palaeontology and Stratigraphy》2014,47(4):500-511
The Luning and Gabbs formations in west‐central Nevada, USA represent a Late Triassic shallow marine sedimentary succession with global significance (the Gabbs Formation was a candidate for the basal Jurassic GSSP). Typically, the Norian–Rhaetian stage boundary is placed at the contact between the formations, and the Rhaetian–Hettangian boundary (the Triassic–Jurassic boundary) is within the Müller Canyon Member of the Gabbs Formation. However, the use of different biostratigraphical index‐species schemes in Norian–Rhaetian successions between Tethys and Panthalassa, the two largest ocean basins at the time, makes precise correlation problematic. Here, we compare 87Sr/86Sr measurements of well‐preserved carbonate shell material from Nevada to the well‐known and biostratigraphically constrained 87Sr/86Sr record from Tethys, where a negative excursion in 87Sr/86Sr is noted across the Norian–Rhaetian boundary. Our new 87Sr/86Sr data from the Luning and Gabbs formations reveal a comparable trend, with a sharp drop in 87Sr/86Sr within the Nun Mine Member of the Gabbs Formation, suggesting the position of the Norian–Rhaetian boundary is higher in the succession, and not between the Luning and Gabbs formations as previously defined. Relating the stage boundary using global isotopic signals is a useful tool for biostratigraphical correlation of successions between Tethys and Panthalassa, and for estimating the rate of faunal turnover at the Norian–Rhaetian stage boundary in comparison with the succeeding Late Triassic mass extinction. If correct, this biostratigraphical–chemostratigraphical correlation suggests that the current index groups for the Panthalassic stage boundary should be changed. 相似文献
7.
Shane J. Prochnow Lee C. Nordt Michael R. Hudec 《Palaeogeography, Palaeoclimatology, Palaeoecology》2006,232(1):53-72
Prior investigations suggest that alluvial lowlands of Pangea in the southwestern U.S.A. during the middle to late Triassic experienced an arid to semiarid climate with significant seasonality. Our investigation finds evidence for a global pluvial episode from paleosols in the middle to late Triassic section of eastern Utah. Multi-proxy paleosol evidence is used to quantify rainfall amounts, ambient temperatures and atmospheric CO2 concentrations and infer associated plant formations related to ecosystem persistence. Rainfall estimates are derived from geochemical molecular weathering ratios; temperature and atmospheric CO2 levels from stable oxygen and carbon isotopes of pedogenic carbonate, respectively; and ecosystem reconstruction by a combination of climate indexes and paleosol characteristics. Eight pedotypes were identified and include poorly drained aquic Entisols (Fisher), well-drained non-aquic Entisols (Salt Valley), calcic Aridisols (Castle Valley), calcic Inceptisols (Moab), cambic (Ute) and calcic (La Sal) Vertisols, dystric Inceptisols (Kokopeli), and argillic Alfisols (Slickrock). The middle Triassic Moenkopi Formation (Anisian) was dominated by Castle Valley paleosols with mean annual rainfall between 300 and 400 mm and mean annual temperature between 13 and 23 °C (mesic to hyperthermic). Based on these climate indexes and root traces, the associated plant formation was most likely desert shrub or dry woodland. The lower Chinle Formation (Carnian) contains a succession of Ute and La Sal paleosols that changed up-section to Kokopeli, Fisher and Slickrock paleosols. In accordance with geochemical and isotopic signatures from these pedotypes, rainfall amounts initially increased to between 700 and 900 mm, and then to between 1300 and 1400 mm. Temperatures estimated from the La Sal paleosol are approximately 18 °C (thermic) at this time. The lower Chinle marks a transition from dry woodland to open forest that appears to correlate with the formation of the Petrified Forest Member in Arizona. The upper Chinle Formation (Carnian-Norian) reveals a return to semiarid to subhumid conditions and the formation of Castle Valley, Moab and Salt Valley paleosols, all of which appear to have supported desert shrub or dry woodlands. Rainfall amounts decreased to between 400 and 600 mm with temperatures eventually increasing to 29 °C (hyperthermic). Using the paleosol isotopic barometer, atmospheric CO2 estimates generally correlate with other proxy for the Triassic. The well-developed Alfisols and noncalcareous Inceptisols identified during the Carnian of the lower Chinle correlate with a previously identified global pluvial episode based on sedimentological and marine isotopic evidence, possibly in response to rifting of Pangea. It should not be assumed that the middle to late Triassic in continental alluvial lowlands supported a uniform, semiarid to arid climate, with strong seasonality. 相似文献
8.
《Comptes Rendus Palevol》2008,7(8):557-569
New observations on the Late Miocene and Earliest Pliocene mustelids from the Middle Awash of Ethiopia are presented. The Middle Awash study area samples the last six million years of African vertebrate evolutionary history. Its Latest Miocene (Asa Koma Member of the Adu-Asa Formation, 5.54–5.77 Ma) and Earliest Pliocene (Kuseralee and Gawto Members of the Sagantole Formation, 5.2 and 4.85 Ma, respectively) deposits sample a number of large and small carnivore taxa among which mustelids are numerically abundant. Among the known Late Miocene and Early Pliocene mustelid genera, the Middle Awash Late Miocene documents the earliest Mellivora in eastern Africa and its likely first appearance in Africa, a new species of Plesiogulo, and a species of Vishnuonyx. The latter possibly represents the last appearance of this genus in Africa. Torolutra ougandensis is known from both the Late Miocene and Early Pliocene deposits of the Middle Awash. The genus Sivaonyx is represented by at least two species: S. ekecaman and S. aff. S. soriae. Most of the lutrine genera documented in the Middle Awash Late Miocene/Early Pliocene are also documented in contemporaneous sites of eastern Africa. The new observations presented here show that mustelids were more diverse in the Middle Awash Late Miocene and Early Pliocene than previously documented. 相似文献
9.
Mohamed Ben Mansour Rafik Balti Lotfi Rabaoui Ali Bougatef Mokhtar Guerfel 《Process Biochemistry》2013,48(4):723-729
The essential oil of Ajuga pseudoiva, collected from Tunisia, was analyzed using gas chromatography–mass spectroscopy. Thirty-two compounds accounting for 95.76% of the total oil were identified. Sesquiterpenes were found to be the most abundant components of A. pseudoiva oil. And they were mainly represented by viridiflorol (30.17%), germacrene B (9.26%) (α, β and γ)-eudesmol (8.11%) and aromadendrene (7.45%). The essential oil of A. pseudoiva showed radical scavengers activity (IC50 = 0.72 mg/mL) and displayed lipid peroxidation inhibitory activity (IC50 = 0.6 mg/mL). A. pseudoiva essential oil was also found to exhibit a dose-dependent ACE inhibitory activity with an IC50 value of 65.5 μg/mL. Moreover, the antimicrobial activity of the essential oil was tested against 17 species of microorganisms, and the results obtained showed significant antibacterial activity against the Gram-positive and Gram-negative bacteria, with inhibition zones and minimal inhibitory concentration values of 14–32 mm and 84–137 μg/mL and 6–21 mm and 105–336 μg/mL, respectively. Higher activity was also found against several fungal strains. 相似文献
10.
Imen Aissa Mohamed Bouaziz Fakher Frikha Riadh Ben Mansour Youssef Gargouri 《Process Biochemistry》2012,47(12):2356-2364
New tyrosyl ester derivative, a naturally occurring phenol with interesting biological properties, has been synthesized in good yield by a direct esterification of tyrosol (Ty) with p-hydroxyphenylacetic acid (p-HPA) using Candida antarctica lipase as a catalyst. The response surface methodology was used to modulate the effects of the enzyme amount (10–50 mg), the tert-butanol/hexane (v/v) ratio (0.16–0.84), the temperature (35–55 °C) and the reaction time (15–45 h) on the tyrosyl hydroxyphenylacetate (Ty-HPA) conversion yield. Under the optimal predicted conditions (enzyme amount: 10 mg, solvents volume ratio 0.16, reaction temperature; 45 °C and 34 h of incubation), a high conversion yield of 79.33 ± 4% was reached. The obtained ester was purified and characterized by NMR, LC/MS and FT-IR methods. ABTS free radical quenching potency demonstrated that the esterified tyrosol (Ty-HPA) was more effective than the natural separated antioxidants: Ty and p-HPA. Furthermore, when used at a non-cytotoxic concentration (100 μM), tyrosyl ester showed significant effectiveness in preventing iron-induced oxidative stress in blood cells compared to the two separated compounds. The antibacterial activity of Ty, p-HPA, mixed solution of Ty + p-HPA and Ty-HPA was performed by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using a micro-well dilution method. Compared to the separated substrates, synthesized ester exhibits the most antibacterial effect mainly against Gram+ bacteria. 相似文献
11.
Andrew Gallagher 《Economics & Human Biology》2013,11(4):551-562
Physical size has been critical in the evolutionary success of the genus Homo over the past 2.4 million-years. An acceleration in the expansion of savannah grasslands in Africa from 1.6 Ma to 1.2 Ma witnessed concomitant increases in physical stature (150–170 cm), weight (50–70 kg), and brain size (750–900 cm3). With the onset of 100,000 year Middle Pleistocene glacial cycles (“ice ages”) some 780,000 years ago, large-bodied Homo groups had reached modern size and had successfully dispersed from equatorial Africa, Central, and Southeast Asia to high-latitude localities in Atlantic Europe and North East Asia. While there is support for incursions of multiple Homo lineages to West Asia and Continental Europe at this time, data does not favour a persistence of Homo erectus beyond ~400,000 years ago in Africa, west and Central Asia, and Europe. Novel Middle Pleistocene Homo forms (780,000–400,000 years) may not have been substantially taller (150–170 cm) than earlier Homo (1.6 Ma–800,000 years), yet brain size exceeded 1000 cm3 and body mass approached 80 kg in some males. Later Pleistocene Homo (400,000–138,000 years) were ‘massive’ in their height (160–190 cm) and mass (70–90 kg) and consistently exceed recent humans. Relative brain size exceeds earlier Homo, yet is substantially lower than in final glacial H. sapiens and Homo neanderthalensis. A final leap in absolute and relative brain size in Homo (300,000–138,000 years) occurred independent of any observed increase in body mass and implies a different selective mediator to that operating on brain size increases observed in earlier Homo. 相似文献
12.
Z.-D. Feng L.X. Wang Y.H. Ji L.L. Guo X.Q. Lee S.I. Dworkin 《Palaeogeography, Palaeoclimatology, Palaeoecology》2008,257(3):335-343
We explored the relationships between surface-soil (1–20 cm) organic carbon isotopic signatures and associated climatic factors in central-east Asia in an attempt to develop transfer functions that can be used to retrieve the paleoclimatic information stored in the thick eolian–paleosol sequences within the area. Our analysis shows that the negative correlation between the surface-soil organic δ13C values and the mean annual precipitation is robust (R2 = 0.453; n = 196; p < 0.05) and the negative correlation with the growing-season (April–September) precipitation is more significant (R2 = 0.4966; n = 196; p < 0.05). Our study further shows that the positive correlation between the surface-soil organic δ13C values and mean growing-season aridity is most significant (R2 = 0.5805; n = 196; p < 0.05). We have smoothed both the organic δ13C values and the mean growing-season aridity values using a 3-point moving-window average-filter method in an attempt to remove some of random errors and found that the positive correlation between the two is further increased (R2 = 0.7784; n = 192; p < 0.05). These robust linear relationships demonstrate their value in reconstructing paleoclimate changes in the study area. The documented climatic dependency of the surface-soil carbon isotopic composition in the study area might have resulted both from the humidity-related isotopic enrichment processes of the dominant C3 plants (stomatal conductance and photosynthetic discrimination) and from the aridity-related abundance of C4 plants (mainly Chenopodiaceae species) along the S–N bioclimatic gradient. 相似文献
13.
Seasonal dynamics in the polyphenolic composition, antioxidant activity, and their relationships during plant development were evaluated for eastern teaberry (Gaultheria procumbens L.) leaves, a traditional herbal medicine of North American natives. With the complementary UHPLC-PDA-ESI-MS3, HPLC-PDA-fingerprint, Folin-Ciocalteau, and n-butanol/HCl assays of methanol-water (75:25, v/v) extracts, the dried leaf samples harvested monthly across the growing season under Polish climate conditions were found rich in structurally diverse polyphenols (149.2–210.7 mg/g DW) including the dominating salicylates (64.6–107.5 mg/g DW), proanthocyanidins (53.0–66.8 mg/g DW), and flavonoids (17.3–25.3 mg/g DW), and the accompanying chlorogenic acid isomers (2.4–4.4 mg/g DW) and simple phenolic acids (0.9–1.1 mg/g DW). Among 28 detected analytes, gaultherin (64.6–107.5 mg/g DW), miquelianin (14.6–21.1 mg/g DW), procyanidin A-type trimer (5.5–9.5 mg/g DW), and (–)-epicatechin (5.8–7.8 mg/g DW) were the most abundant. The phenolic levels and antioxidant activity parameters in the DPPH (EC50, 15.0–18.2 μg DW/mL; 0.95–1.16 mmol Trolox equivalents/g DW) and FRAP (2.3–3.4 mmol Fe 2+/g DW; 0.86–1.26 mmol Trolox equivalents/g DW) assays showed parallel seasonal trends with maxima in September and October. As the subsequent correlation studies confirmed the determinative impact of polyphenols on the leaf antioxidant activity and its seasonal fluctuations, the Fall season could be recommended as optimal for harvesting the plant material for medicinal purposes and cost-effective production of natural health products. 相似文献
14.
We combine cyclo- and sequence stratigraphy along with whole rock δ13C and conodont apatite δ18O analysis to document high-frequency (104–105 yr) and My-scale sea-level changes for the Middle Pennsylvanian (Desmoinesian or Moscovian) Gray Mesa Formation of central New Mexico. Approximately 75 subtidal cycles (1–8 m) are grouped into 4 1/2 My-scale depositional sequences (40–80 m). About 50% of the cycles show evidence of prolonged subaerial exposure at cycle tops with the development of calcretes, diagenetic mottling, and regolith intraclasts. High-resolution δ13C analysis of whole rock limestones across nine of the cycles indicates that the cycle tops were diagenetically altered by isotopically light, meteoric fluids during sea-level fall and lowstand. These δ13C trends support the interpretation that high-frequency sea-level changes were responsible for cycle development.Conodont apatite δ18O values from sampled cycles indicate that the high-frequency sea-level changes were driven by glacio-eustasy combined with changes in surface seawater temperature (SST). δ18O values from conodont apatite, spanning parts of three depositional sequences indicate that My-scale glacio-eustasy and/or SST changes controlled sequence development. δ18O shifts indicate that the magnitudes of 104–105 yr glacio-eustasy were between ~ 55 and 170+ m combined with tropical SST changes of ~ 1.5°–6 °C. Calculated My-scale glacio-eustatic oscillations were between ~ 60 and 140 m with SST changes of < 3.5 °C. The most plausible driver for the My-scale paleoclimate changes is long-period obliquity (~ 1.2 My) variations. These calculated high-frequency, glacio-eustatic values are similar or greater than Pleistocene values, and lie within the range estimated for other Middle Pennsylvanian successions using a variety of independent eustatic proxies. The similarity in range of magnitudes between high-frequency and My-scale sea-level changes combined with the large differences in magnitudes between individual high-frequency sea-level oscillations helps explain the lack of systematic cycle-stacking patterns within these Pennsylvanian icehouse sequences. 相似文献
15.
IntroductionBreast cancer is the most common malignancy in Mexican women since 2006. However, due to a lack of cancer registries, data is scarce. We sought to describe breast cancer trends in Mexico using population-based data from a national database and to analyze geographical and age-related differences in incidence and mortality rates.MethodsAll incident breast cancer cases reported to the National Epidemiological Surveillance System and all breast cancer deaths registered by the National Institute of Statistics and Geography in Mexico from 2001 to 2011 were included. Incidence and mortality rates were calculated for each age group and for 3 geographic regions of the country. Joinpoint regression analysis was performed to examine trends in BC incidence and mortality. We estimated annual percentage change (APC) using weighted least squares log-linear regression.ResultsWe found an increase in the reported national incidence, with an APC of 5.9% (95% CI 4.1–7.7, p < 0.05). Women aged 60–65 had the highest increase in incidence (APC 7.89%; 95% CI 5.5 −10.3, p < 0.05). Reported incidence rates were significantly increased in the Center and in the South of the country, while in the North they remained stable. Mortality rates also showed a significant increase, with an APC of 0.4% (95% CI 0.1–0.7, p < 0.05). Women 85 and older had the highest increase in mortality (APC 2.99%, 95% CI 1.9–4.1; p < 0.05).ConclusionsThe reporting of breast cancer cases in Mexico had a continuous increase, which could reflect population aging, increased availability of screening, an improvement in the number of clinical facilities and better reporting of cases. Although an improvement in the detection of cases is the most likely explanation for our findings, our results point towards an epidemiological transition in Mexico and should help in guiding national policy in developing countries. 相似文献
16.
Background: The innervation zone (IZ) corresponds to the location of the neuromuscular junctions. Its location can be determined by using arranged surface linear electrode arrays. Typically, voluntary muscle contractions (VC) are used in this method. However, it also may be necessary to locate the IZ under clinical conditions such as spasticity, in which this type of contraction is difficult to perform. Therefore, contractions imposed by electrostimulation (ES) can be an alternative. There is little background comparing the locations of IZ obtained by two different types of contractions. Objective: Evaluate the concordance between using voluntary and imposed contractions from electrostimulation in order to determine the location of the innervation zone of the tibialis anterior muscle in healthy volunteers. Methods: The tibialis anterior (TA) muscle of sixteen volunteers (men: 8; women: 8; age: 22.1 ± 1.4 years, weight: 61.6 ± 7.5 kg, height: 167.1 ± 7.5 cm) were evaluated using a linear electrode array. The IZ of the TA muscle was located using two types of muscle contractions, voluntary (10% MVC) and imposed contractions by ES. The concordance between both conditions was evaluated using the Bland–Altman method and the concordance correlation coefficient (CCC). The analyses were applied to the absolute and relative positions to the length of an anatomical landmark frame. Results: CCC for absolute position was 0.98 (p < 0.0001, 95% CI [0.98–1.00], and CCC for relative positions also was 0.98 (p < 0.0001, 95% CI [0.97–1.00]). The Bland–Altman analysis for absolute data showed an average difference of −0.63 mm (SD: 4.1). Whereas, for adjusted data, the average difference was −0.20% (SD: 1.2). The power of the results, based on absolute data, was 98%, whereas for relative data, 82%. Conclusion: In healthy volunteers, there was a substantially concordance between the location of the IZ of the TA muscle derived from using contractions imposed by ES and the location derived from using VC. 相似文献
17.
Judith Schellekens Peter Buurman Isabel Fraga Antonio Martínez-Cortizas 《Palaeogeography, Palaeoclimatology, Palaeoecology》2011,299(1-2):56-69
Peat molecular chemistry reflects a combination of plant input and decomposition. Both vegetation community and the degree of decomposition of plant remains are highly dependent on depth and fluctuation of the water table and thus peat organic matter (OM) chemistry reflects past hydrological conditions. Changes in hydrology according to the OM composition (by pyrolysis-gas chromatography/mass spectrometry, pyrolysis-GC/MS) in a high-resolution sampled monolith of an 8000 years old peat deposit are presented. Analysis of 18 modern vegetation species resulted in molecular markers for Erica spp., Deschampsia flexuosa, Juncus bulbosus and Carex binervis, in addition to more general markers which enabled differentiation between woody, grass and moss vegetation. Factor analysis of 106 pyrolysis products quantified for all peat samples enabled identification of mineral (Factor 1) and hydrological (Factor 2) conditions of the bog. Depth profiles of vegetation markers showed good agreement with those of the scores of both factors and enabled the identification of 14 relatively wet periods, dating to 1430–1865 AD, 930–1045 AD, 640 AD, 270–385 AD, 190–215 AD, 135 AD, 45 BC–15 AD, 260–140 BC, 640–440 BC, 1055–960 BC, 1505–1260 BC, 2300 BC, 4190–2945 BC and 5700–5205 BC, which show excellent agreement with other palaeoclimatic studies in Europe. The results emphasize the importance of high-resolution sampling, in combination with the use of multiple vegetation markers and other peat OM characteristics for a proper interpretation of a peat record. 相似文献
18.
《Harmful algae》2016
The toxic marine dinoflagellate, Karenia brevis (the species responsible for most of red tides or harmful algal blooms in the Gulf of Mexico), is known to be able to swim vertically to adapt to the light and nutrient environments, nearly all such observations have been made through controlled experiments using cultures. Here, using continuous 3-dimensional measurements by an ocean glider across a K. brevis bloom in the northeastern Gulf of Mexico between 1 and 8 August 2014, we show the vertical migration behavior of K. brevis. Within the bloom where K. brevis concentration is between 100,000 and 1,000,000 cells L−1, the stratified water shows a two-layer system with the depth of pycnocline ranging between 14–20 m and salinity and temperature in the surface layer being <34.8 and >28 °C, respectively. The bottom layer shows the salinity of >36 and temperature of <26 °C. The low salinity is apparently due to coastal runoff, as the top layer also shows high amount of colored dissolved organic matter (CDOM). Within the top layer, chlorophyll-a fluorescence shows clear diel changes in the vertical structure, an indication of K. brevis vertical migration at a mean speed of 0.5–1 m h−1. The upward migration appears to start at sunrise at a depth of 8–10 m, while the downward migration appears to start at sunset (or when surface light approaches 0) at a depth of ∼2 m. These vertical migrations are believed to be a result of the need of K. brevis cells for light and nutrients in a stable, stratified, and CDOM-rich environment. 相似文献
19.
Li Juan Yuan Tian Bo Jin Ji Kai Yin Xi Lin Du Qing Wang Rui Dong Sheng Zhi Wang Yan Cui Chao Chen Jian Guo Lu 《Cancer epidemiology》2012,36(6):e366-e372
BackgroundGastric cancer is the fourth most common cancer in the world. Environmental and genetic factors both play critical roles in the etiology of gastric cancer. Hundreds of SNPs have been identified to have association with the risk of gastric cancer in many races. In this study, 25 SNPs in genes for IL-10, IL-1B, MTRR, TNF-а, PSCA, PLCE1 and NOC3L were analyzed to further evaluate their associations with gastric cancer susceptibility in the Chinese Han population.MethodsTwo hundred and seventy nine gastric cancer patients and 296 healthy controls were recruited in this study. SNP genotyping was conducted using Sequenom MassARRAY RS1000. Data management and statistical analyses were conducted by Sequenom Typer 4.0 Software and Pearson's χ2 test.ResultsOne protective allele and three risk alleles for gastric cancer patients were found in this study. The allele “G” of rs1801394 in MTRR showed an association with a decreased risk of gastric cancer: odds ratio (OR) = 0.74, 95% confidence interval (95% CI) = 0.57–0.97, P = 0.030 in the additive model; OR = 0.495, 95% CI = 0.26–0.95, P = 0.034 in the recessive model. The other three SNPs, the allele “C” of rs1800871 in IL10 (OR = 1.33, 95% CI = 1.04–1.90; P = 0.026 in the additive model; OR = 1.46, 95% CI = 1.04–2.06; P = 0.030 in the recessive model), the allele “A” of rs2976391 in PSCA (OR = 1.30, 95% CI = 1.01–1.66; P = 0.041 in the additive model and OR = 1.48, 95% CI = 1.04–2.11, P = 0.028 in the recessive model), and the allele “G” of rs17109928 in NOC3L gene (OR = 1.34, 95% CI = 1.01–1.78; P = 0.042 by additive model analysis; OR = 1.47, 95% CI = 1.04–2.07, P = 0.028 by dominant model analysis), showed an association with an increased risk of gastric cancer.ConclusionsThese results indicate the importance of four gastric cancer susceptibility polymorphisms of IL-10, NOC3L, PSCA and MTRR in the Chinese Han population, which could be used in the determination of gastric cancer risk in clinical practice. 相似文献
20.
Jong-Kook Jung Seung-Tae Kim Sue-Yeon Lee Chang-Gyu Park Jong-Kyun Park Joon-Ho Lee 《Journal of Asia》2012,15(3):487-494
We conducted this study to determine the diversity patterns, community structures, and seasonality of ground beetle assemblages along an altitudinal gradient (437–1420 m) on Mt. Sobaeksan, Korea. Ground beetles were collected by pitfall traps installed along an altitudinal gradient (437, 757, 1100, and 1420 m). A total of 32 species belonging to seven subfamilies were identified from 3259 collected ground beetles. The diversity pattern of the ground beetle assemblage according to altitude was neither monotonic decreased nor hump-shaped. However, subfamily assemblages and wing form diversity patterns differed according to altitude and may be correlated with altitude or some other environmental variables. The dominant species were Synuchus cycloderus (29.4%) and Eucarabus sternbergi sobaeksanensis (15.4%) and their seasonal activities according to altitude were similar. According to non-metric multidimensional scaling, ground beetles and altitudes could be divided into two distinct groups: a low altitude group (437–757 m) and a high altitude group (1100–1420 m). Some species were particularly abundant at high altitudes, such as Aulonocarabus koreanus kwonileeique and Poecilus nitidicollis, while others were highly abundant at low altitudes, such as Pterostichus audax, Pterostichus ishikawai, and Synuchus species. 相似文献