Lower-middle Part Research Articles

Wenlock–Ludlow boundary interval revisited: new insights from the offshore facies of the Prague Synform, Czech Republic

Wenlock–Ludlow boundary beds exposed near Nesvačily in the Prague Synform are documented in terms of their lithology, faunal content, high-resolution record of 19 graptolite species, graptolite biostratigraphy, and conodont record. This is the first time in Bohemia and peri-Gondwanan Europe that a continuous graptolite-bearing section through upper ludensis – middle nilssoni biozones is described in detail to refine high-resolution biostratigraphy and correlation of the Wenlock–Ludlow boundary. Organic-rich shale, relatively rare nongraptolite fauna, and absence of bioturbation indicate a stable deep-water offshore setting with sporadic, low-level bottom oxygenation. The uninterrupted succession revealed a series of origination events of principal graptolite taxa employed in determination of the Wenlock–Ludlow boundary strata worldwide. Bohemograptus represented by B. praecox appeared as early as in the uppermost Wenlock ludensis Biozone. Bohemograptus praecox is later accompanied and replaced by B. bohemicus, associated with Uncinatograptus uncinatus. The lowest Neodiversograptus nilssoni marked the base of the Ludlow nilssoni Biozone. Speciation within Bohemograptus continued in the middle nilssoni Biozone when the robust B. butovicensis evolved from B. bohemicus. Colonograptus colonus shows its lowest occurrence in the middle part of the nilssoni Biozone together with the latest C. gerhardi. The monograptids are associated with abundant and diverse plectograptids that are at present mostly known from Baltica. Bohemograptus praecox sp. nov. and B. butovicensis ( Bouček, 1936 ) are described in the systematic part. The conodont Kockelella ortus absidata, found in the lower–middle part of the nilssoni Biozone, is consistent with a stratigraphic interval within Oz. bohemica and K. crassa conodont biozones.

Erosion patterns in the Changjiang (Yangtze River) catchment revealed by bulk-sample versus single-mineral provenance budgets

The Changjiang, the fourth longest river on Earth and the largest in Eurasia, has a complex sediment-routing system presently interrupted by the Three Gorges Dam, the world's largest hydroelectric engineering project. To study sediment-generation processes in the huge catchment and compare the different erosion patterns obtained by different methodological approaches, high-resolution petrographic and heavy-mineral analyses were performed on sands from the trunk river and its major tributaries. The frequency distributions of diverse groups of detrital amphiboles were also investigated. Rigorous statistical methods were used to define end-members, evaluate mineralogical variability, assess similarities among samples, and eventually calculate the relative contributions from each major tributary to the trunk river by forward end-member modelling of integrated compositional data. The litho-quartzose sand with few heavy minerals generated in Tibetan headwaters evolves downstream to feldspatho-litho-quartzose with medium-rank metamorphic rock fragments and moderately rich amphibole-epidote suites. Sand across the Sichuan basin and as far as the Three Gorges Dam is enriched in mafic volcanic, clinopyroxene, and carbonate grains eroded from Permian basalts and Paleozoic strata of the South China Block. The final (Yangtze) tract is characterized by litho-feldspatho-quartzose sand with moderately poor, amphibole-dominated suites with epidote, clinopyroxene, and garnet. The orogenic compositional signature acquired in the upper part of the basin is thus carried all the way to the Chinese passive margin, as observed also for the Yellow River in the north. Even after long-distance transport across wide continental areas, detrital modes thus reveal the tectonic character of the source rather than the geodynamic environment of the sink.Quantitative provenance analysis indicates that left-bank tributaries draining the Longmen and Qinlin mountains supply most of the sand reaching the East China Sea. Contributions from Tibetan headwaters are negligible, as those from right-bank tributaries in the middle-lower part of the basin. Sediment budgets and erosion patterns inferred from our integrated petrographic and heavy-mineral data set contrast with those based on detrital-zircon geochronology but agree with stream-profile analysis, revealing close correspondence with slope steepness, precipitation, stream power, tectonic activity, and frequency of major earthquakes. Sediment budgets based on amphibole groups are poorly constrained. We conclude that provenance budgets based on single-mineral species are typically unrobust, particularly because they suffer from inaccurate estimates of mineral concentration in the end-member sources. Exploring in detail a millesimal part of the sediment (typically 1/5000 in the case of zircon) is a risky strategy that may return a distorted picture of reality.

Different tonotopic regions of the lateral superior olive receive a similar combination of afferent inputs.

The mammalian lateral superior olive (LSO) codes disparities in the intensity of the sound that reaches the two ears by integrating ipsilateral excitation and contralateral inhibition, but it remains unclear what particular neuron types convey acoustic information to the nucleus. It is also uncertain whether the known conspicuous morphofunctional differences and gradients along the tonotopic axis of the LSO relate to qualitative and/or quantitative regional differences in its afferents. To clarify these issues, we made small, single injections of the neuroanatomical tracer biotinylated dextran amine (BDA) into different tonotopic regions of the LSO of albino rats and analyzed the neurons labeled retrogradely in brainstem auditory nuclei. We demonstrate that the LSO is innervated tonotopically by four brainstem neuron types: spherical bushy cells and planar multipolar neurons of the ipsilateral ventral cochlear nucleus, principal neurons of the ipsilateral medial nucleus of the trapezoid body, and small multipolar neurons of the contralateral ventral nucleus of the trapezoid body. Unexpectedly, the proportion of labeled neurons of each type was virtually identical in all cases, thus indicating that all tonotopic regions of the LSO receive a similar combination of inputs. Even more surprisingly, our data also suggest that the representation of frequencies in the LSO differs from that of the nuclei that innervate it: compared to the latter nuclei, the LSO seems to possess a relatively larger portion of its volume devoted to processing frequencies in the lower-middle part of the spectrum, and a relative smaller portion devoted to higher frequencies. J. Comp. Neurol. 524:2230-2250, 2016. © 2015 Wiley Periodicals, Inc.

The biotic crisis across the Oceanic Anoxic Event 2: Palaeoenvironmental inferences based on foraminifera and geochemical proxies from the South Iberian Palaeomargin

Open marine sediments deposited during the Cenomanian–Turonian transition are well exposed in the Spanish Baños de la Hedionda section (Betic Cordillera, South Iberian Palaeomargin). Analysis of foraminiferal assemblages and geochemical proxies allow inferences on the impact of the Oceanic Anoxic Event 2 (OAE2) in this area of the western Tethys. Three main intervals have been identified corresponding to different lithological units and biozones. (1) The top of the Capas Blancas Member (Rotalipora cushmani Biozone) represents the pre-extinction phase with diverse foraminiferal assemblages and well developed water-column tiering, well-oxygenated, oligotrophic deep-waters and oxygenated to poorly oxygenated, mesotrophic surface-waters. Foraminiferal opportunist species point to a minor event with dysoxic conditions preceding the OAE2. (2) The black radiolaritic shales (Whiteinella archaeocretacea Biozone) consist of a foraminiferal-barren interval, except for the lowermost centimetres where planktic surface-dweller opportunists are common. Redox sensitive elements (Cr/Al, V/Al, U/Th, MoEF, Moaut, UEF and Uaut) and increased TOC values reflect oxygen depleted conditions related to the OAE2. The increase in P/Ti values at the base of this stratigraphic interval indicates an abrupt increase in productivity. High concentrations of radiolarians are congruent with high surface productivity probably related to changes in oceanic circulation and enhanced upwelling currents, as well as subsequent shallowing of the oxygen-minimum zone. The increase in MoEF and Moaut towards the top of the black radiolaritic shales indicates temporal euxinic conditions. (3) A slow, bottom-up recovery of foraminiferal assemblages is inferred at the base of the Boquerón Member (Helvetoglobotruncana helvetica Biozone), with seafloor recolonization by benthic foraminifera being recorded previous to the water column colonization by planktic forms, mainly by intermediate-dwellers typical of mesotrophic waters. The subsequent proliferation of surface-dweller opportunists and deep-dweller opportunists adapted to mesotrophic to eutrophic conditions, and the decrease in planktic foraminiferal diversity, may indicate the persistence of poorly oxygenated conditions in the water column towards the lower-middle part of the H. helvetica Biozone.

A sedimentary paleomagnetic record of the upper Jaramillo transition from the Lantian Basin in China

The termination of the Jaramillo (normal to reverse) subchron is a key chronostratigraphic marker for dating global Pleistocene sedimentary sequences. However, the stratigraphic position of the geomagnetic polarity reversal varies greatly across the Chinese Loess Plateau (CLP), from near the bottom of paleosol unit S9 to the middle-upper part of S10. Here, we present paleomagnetic and rock magnetic results from high-resolution sampling of the Yushan loess section of the Lantian Basin located within the southern CLP. Our combined analyses determine that the polarity reversal is located in the middle-lower part of the paleosol unit S10. This stratigraphic position is lower than most of other studies conducted throughout the CLP. We attribute the difference in the location of the reversal to a deeper lock-in depth of remanence acquisition, which may have occurred from postdepositional processes under favorable hydrothermal conditions along the southern margin of CLP. It is important to note that age determinations through magnetic stratigraphy on sedimentary sections, particularly in discontinuous and/or imperfect sequences, should be treated with caution; there are significant differences with respect to the location of the polarity reversal throughout the CLP.

Early Eocene rodents (Mammalia) from the Subathu Formation of type area (Himachal Pradesh), NW sub-Himalaya, India: Palaeobiogeographic implications

Based on isolated upper cheek teeth, two new early Eocene rodents (Subathumys solanorius gen. et sp. nov. and Subathumys globulus gen. et sp. nov.) and three others (Birbalomys cf. sondaari, Birbalomys sp., cf. Chapattimys sp.) are recorded from the lower–middle part of the Subathu Formation of the type area in Himachal Pradesh, northwestern sub-Himalaya (India). The new rodents exhibit morphological features most similar to the unified ctenodactyloid family Chapattimyidae (including Yuomyidae), which is also represented in the assemblage from the upper part (middle Eocene) of the Subathu Formation. The associated lower cheek teeth are provisionally described as three indeterminate chapattimyid taxa. The new Subathu rodents are somewhat younger than the previously documented early Eocene assemblages from the Indian subcontinent, and are chronologically intermediate between the early Eocene ailuravines from Gujarat in the western peninsular India and the middle Eocene chapattimyids from northwestern India and Pakistan. They suggest that chapattimyids originated in the sub-Himalayan region during the Ypresian, which is earlier than previously believed. The absence of ailuravines in this as well as younger rodent assemblages from the subcontinent seems to suggest that ailuravines (Ischyromyidae), within a relatively short time after their appearance in the peninsular India in the early Eocene, may have been replaced by the indigenous chapattimyids. The co-occurrence in the early Eocene Subathu assemblage of three or more chapattimyids indicates their early radiation and dominance during the early and middle Eocene. This record of rodents opens the possibility of recovery of other small mammal remains in older levels of the Subathu Formation, which will be important for understanding linkage with early Eocene faunas from peninsular India, Europe and North America.

Last occurrence of Abathomphalus mayaroensis (Bolli) foraminiferid index of the Cretaceous–Paleogene boundary: the calcareous nannofossil proof

AbstractIn the Gaj section (Polish Carpathians, Skole Nappe, Ropianka Formation), the Late Maastrichtian calcareous nannofossil biostratigraphy is compared with foraminiferal zonation based on the occurrence of the planktonic foraminiferid index speciesAbathomphalus mayaroensis. It appears that the LO ofA. mayaroensis, which has been used previously in the studied section as the possible K/Pg boundary indicator is located below the boundary. The disappearance ofA. mayaroensisalong with other planktonic foraminiferids before the Cretaceous–Paleogene (K/Pg) boundary mass extinction event may be a consequence of the Late Maastrichtian rapid warming pulses. Moreover, the Paleogene age cannot be supported by the FO of the benthic foraminiferidRzehakina fissistomata,because it first appears together with the nannofossilCeratolithoides kamptneri(zonal marker for the latest Maastrichtian UC20cTPZone). According to the present study, the whole studied section represents the lower Upper to the upper Upper Maastrichtian UC20bTPand UC20cTPnannofossil zones, so that it corresponds to the lower-middle part of the planktonic foraminiferalA. mayaroensisZone, which, according to the scheme by Caron (1985), should extend up to the K/Pg boundary.

Geochemical and paleoenvironmental record of the early to early late Aptian major episodes of accelerated change: Evidence from Sierra del Rosario, Northeast Mexico

The lower to lower-upper Aptian succession of northern Mexico documents the drowning of the shallow-water Cupido/Cupidito carbonate platform system followed by deposition of the deep-water sediments of the La Peña Formation. Using δ13C stratigraphy, geochemical and mineralogical information coupled with previous microfacies, paleontological and total organic carbon (TOC) data from a stratigraphic section, which includes such lithological change, this study identifies distinctive episodes of accelerated global environmental change, and determines the paleoenvironmental conditions conducive to the deposition of TOC-rich intervals. Within the Cupidito unit, the Oceanic Anoxic Event 1a (OAE 1a) is recorded near the base of the section and the Intra-Furcata Negative Excursion in the topmost beds of the unit. The upper part of the section, within the La Peña Formation, is correlatable with the Noire level. Organic-carbon rich intervals occur in the lower and middle part of the OAE 1a, upper part of the Cupidito unit, base of the La Peña Formation, and in the Noire level equivalent. Reducing conditions within the sediment and oxic–dysoxic at the seafloor, locally controlled, persisted both before and during OAE 1a interval in the Cupidito lagoon. Oxygen-depleted conditions (dysoxic–anoxic) were more permanent and stronger during the deposition of the base of the la Peña Formation and the Noire equivalent level. It is proposed here that deposition of the lower-middle part of the OAE 1a and the base of the La Peña Formation was influenced by climate-controlled increases in detrital and accompanying nutrient influx that supplied especially biolimiting nutrients (Fe, P), fostering marine productivity and TOC burial. Upwelling of nutrient-rich deeper waters and minor arrival of nutrients from runoff, both account for the domination of radiolaria and organic-carbon burial during the Noire level equivalent. Record of the OAE 1a time-equivalent facies in the Cupidito lagoonal sediments confirms the diachronism of the Cupidito–La Peña flooding. Heterozoan carbonate production in the Cupidito ramp was uninterrupted during and after OAE 1a. Periodic arrival of detrital components and nutrients during warmer/humid periods accelerated platform drowning, which peaked during the diachronic deposition of the La Peña Formation.

A New Gas Injection System for Ultra-Thick Metamorphic Rock Buried Hill Reservoirs

This article proposes a new gas injection system that is a kind of tridimensional gas injection mode applied in the middle-lower part of the reservoir during the process of gas injecting on the reservoir top, which is suitable for the tridimensional reservoir development[1-2]. This system can express the gravity-stable drive effect on the crestal gas injection as well as the effective using of waterflooded wells to form continual micro gas/water slug drive naturally, supply the producing energy timely, diminish the water sealing of waterflooded reservoir matrix, enhance the gas dialysis on fine crack and microscopic sweep efficiency and control the water content, thus improve the production rate and enhance the recovery. Tridimensional gas injection system has been verified by physical simulation and numerical simulation. Pilot testing on Xinggu 7 buried hill reservoir has acquired an actual effect to increase the oil production, boost the pressure and decrease the water cut. Key words: Tridimensional; Gas injection system; Ultra-thick reservoir; Buried hill; Gravity-stable drive; Waterflooded well

Kinematics of the thoracic spine in trunk lateral bending: in vivo three-dimensional analysis

Background contextIn vivo three-dimensional kinematics of the thoracic spine in trunk lateral bending with an intact rib cage and soft tissues has not been well documented. There is no quantitative data in the literature for lateral bending in consecutive thoracic spinal segments, and there has not been consensus on the patterns of coupled motion with lateral bending. PurposeTo demonstrate segmental ranges of motion (ROMs) in lateral bending and coupled motions of the thoracic spine. Study designIn vivo three-dimensional biomechanics study of the thoracic spine. Patient sampleFifteen healthy male volunteers. Outcome measuresComputed analysis by using voxel-based registration. MethodsParticipants underwent computed tomography of the thoracic spine in three supine positions: neutral, right maximum lateral bending, and left maximum lateral bending. The relative motions of vertebrae were calculated by automatically superimposing an image of vertebrae in a neutral position over images in bending positions, using voxel-based registration. Mean values of lateral bending were compared among the upper (T1–T2 to T3–T4), the middle-upper (T4–T5 to T6–T7), the middle-lower (T7–T8 to T9–T10), and the lower (T10–T11 to T12–L1) parts of the spine. ResultsAt lateral bending, the mean ROM (±standard deviation) of T1 with respect to L1 was 15.6°±6.3° for lateral bending and 6.2°±4.8° for coupled axial rotation in the same direction as lateral bending. The mean lateral bending of each spinal segment with respect to the inferior adjacent vertebra was 1.4°±1.3° at T1–T2, 1.3°±1.2° at T2–T3, 1.4°±1.3° at T3–T4, 0.9°±0.9° at T4–T5, 0.8°±1.0° at T5–T6, 1.1°±1.1° at T6–T7, 1.7°±1.2° at T7–T8, 1.3°±1.2° at T8–T9, 1.6°±0.7° at T9–T10, 1.8°±0.8° at T10–T11, 2.3°±1.0° at T11–T12, and 2.2°±0.8° at T12–L1. The smallest and the largest amounts of lateral bending were observed in the middle-upper and the lower parts, respectively. There was no significant difference in lateral bending between the upper and the middle-lower parts. Coupled axial rotation of each segment was generally observed in the same direction as lateral bending. However, high variability was found at the T2–T3 to T5–T6 segments. Coupled flexion was observed at the upper and middle parts, and coupled extension was observed at the lower part. ConclusionsThis study revealed in vivo three-dimensional motions of consecutive thoracic spinal segments in trunk lateral bending. The thoracolumbar segments significantly contributed to lateral bending. Coupled axial rotation generally occurred in the same direction with lateral bending. However, more variability was observed in the direction of coupled axial rotation at T2–T3 to T5–T6 segments in the supine position. These results are useful for understanding normal kinematics of the thoracic spine.

Effect of net terrace biological bank on soil nutrients distributions along slope

网格式生物埂作为将水土保持生物措施与工程措施相结合的一种新型护坡技术, 对土壤养分特征和坡面分布规律有较大影响。本文采用野外调查和室内分析方法, 研究建设1~4年的黄花网格式生物埂对坡面土壤养分分布特点和分布规律的影响。结果表明: (1)网格式生物埂对土壤有机质含量和pH有显著改善作用, 随着建设年限的增加, 土壤pH逐渐降低, 而土壤有机质含量逐渐增大; 在不同坡位之间有机质含量表现为: 坡上>坡中>坡下, 与对照裸坡呈相反规律; (2)随着网格式生物埂建设年限的增加, 土壤全氮呈现先降低后增加的趋势, 且生物埂对于改善上坡位氮素含量效果较显著; 土壤碱解氮与全氮含量变化呈显著正相关, 且不同建设年限间生物埂土壤碱解氮含量在坡上和坡下位置差异均较显著; (3)生物埂建设1~3年, 相同年限的生物埂不同坡位的土壤全磷含量之间显著差异性规律不同, 但建设4年生物埂土壤全磷的坡面分布规律与对照完全相反, 表现为坡下>坡中>坡上, 且不同坡位差异达极显著水平(<i>P</i>=0.000); 有效磷含量随生物埂建设年限增加表现出一定的波动性, 变异系数达31.37%, 但相比对照平均值提高1.15~3.30倍, 而坡面分布随建设年限没有明显的变化规律; (4)网格式生物埂土壤全钾含量相比对照提高9.7%~28.2%, 但随着网格式生物埂建设年限的增加, 土壤全钾含量呈降低趋势; 生物埂能显著增加土壤有效钾含量, 且达到一定建设年限, 坡面不同位置土壤有效钾含量差异性显著增加。

A NEW SPECIES OF SAURICHTHYS (ACTINOPTERYGII) FROM THE MIDDLE TRIASSIC (EARLY LADINIAN) OF THE NORTHERN GRIGNA MOUNTAIN (LOMBARDY, ITALY)

A new species of Saurichthys is described. It comes from an Early Ladinian fossil-bearing bed lying in the middle-lower part of the Buchenstein Formation on the Northern Grigna southern slope (Pasturo, Lecco). This new species differs from the several other Middle Triassic species in the remarkable size (more than 130 cm in length), in the presence of a grid structure made by the dorsal elements of its vertebral column, and in the posteriorly enlarging endoskeletal elements of both dorsal and anal fins. Moreover, only two longitudinal scale rows distinguish this taxon; together with the grid structure of the dorsal vertebral column, this character was previously observed only in Norian species (Late Triassic). The early appearance of these features in a Ladinian species opens a new, serious discussion on the evolutionary trends of Saurichthys , which is a very important genus, inhabiting the seas and lakes all over the world from the latest Permian to the end of the Triassic.

A rare microstructure: trapezoid-shaped aggregate of fine-grained minerals

A curved fault plane passes from lower middle part of the snap up to the upper right corner within recrystallized very fine-grained aggregate of quartz (white arrows), chlorites (red arrows) and other clay minerals. Near the upper right side of the photo, a trapezoidal aggregate (yellow broken ellipse) is discernible at a single side of the fault. A much smaller trapezoid with more straight margins is also visible adjacent to the fault plane. Trapezoids have rarely been described as a shape fabric (e.g. fig. 2.18 of Trouw et al. 2010; Mukherjee 2012, 2013a) and have been interpreted as a thrust slices in microscale. In shear zones, precipitation of syn-tectonic chlorite (parallel to shear planes) in the pre-existing quartzose veins indicates a late-stage reactivation of the thrust under low-grade PT conditions

New Schizolepis Fossils from the Early Cretaceous in Inner Mongolia, China and its Phylogenetic Position

Abstract:Three Schizolepis species collected from the Lower Cretaceous layer of the Huolinhe Basin, Inner Mongolia, China are described. These fossils are Schizolepis longipetiolus Xu XH et Sun BN sp. nov., which is a new species, Schizolepis cf. heilongjiangensis Zheng et Zhang, and Schizolepis neimengensis Deng. The new species is a well‐preserved female cone, slender and cylindrical in shape. The seed–scale complexes have long petioles and are arranged on the cone axis loosely and helically. The seed scales are divided into two lobes from the base. Each lobe is semicircular or elongate ligulate in shape, widest at the middle or the lower middle part, with an obtuse or bluntly pointed apex. The inner margin is almost straight and the outer margin is strongly arched. On the surface of the lobe, there are longitudinal and somewhat radial striations from the base to the margin. The seed is borne on the adaxial surface at the base or middle of each lobe. Schizolepis was established in 1847, and, although more than twenty species have been discovered and reported, its phylogenetic position is controversial because of the imperfection of fossils. Most authors have considered there to be a close evolutionary relationship between Schizolepis and extant Pinaceae. Here, we analyze characteristics and compare Schizolepis with Picea crassifolia Kom, which is morphologically most similar to Schizolepis. The results indicate that the genus probably has a distant evolutionary relationship with extant Pinaceae. A detailed statistical analysis of the global paleogeographic distribution of Schizolepis showed that all the fossils of this genus appeared in strata ranging from the Upper Triassic to the Lower Cretaceous in the North Hemisphere, being rare in the Upper Triassic and Lower Jurassic, but being very common from the Middle Jurassic to the Lower Cretaceous, and particularly abundant in the Lower Cretaceous. According to the statistical results, we speculate that the genus originated in Europe in the Late Triassic then spread from Europe to Asia between the Late Triassic and the Late Jurassic. In the Early Cretaceous most species existed in China's three northeastern Provinces and the Inner Mongolia Autonomous Region and adjacent areas. Combining the paleogeographic distribution of the genus with ancient climatic factors, we deduced that Schizolepis began to decline and became extinct in the Early Cretaceous, and the reason for its extinction is closely related to the icehouse climate during the Early Cretaceous.

낙동강 중·하류의 식물플랑크톤 군집구조 분석

A seasonal variation of phytoplankton community in the middle-lower part of the Nakdong River was studied in four sampling stations at monthly intervals from January to December 2012. We identified 40 genera 72 species of phytoplankton. Among these, diatoms were 36 species (50.0%), green algae 20 species (27.8%), blue-green algae 9 species (12.5%) and others 7 species (9.7%), respectively. The phytoplankton standing crops were recorded a maximum of 29,640 cells/mL at the Mulgeum (St. 4) in June and a minimum of 236 cells/mL at the Goryung (St. 1) in October. Also, Standing crops were increased with proceeding from middle part to lower part. Ecological important species were Stephanodiscus hantzschii, Cyclotella meneghiniana, Synedra acus, Aulacoseira granulata, Pediastrum sp. and Microcystis aeruginosa. Seasonal succession of phytoplankton represented that Stephanodiscus hantzschii was dominant species in winter, Cyclotella meneghiniana, Synedra acus was dominant species in spring, Microcystis aeruginosa, Cyclotella meneghiniana, Fragilaria crotonensis, Synedra acus, Aulacoseria granulata was dominant species in summer, and Aulacoseria granulata, Cyclotella meneghiniana, Fragilaria crotonensis was dominant species in autumn. In the community analysis, diversity index and dominant index were higher May~July and December~February, respectively. Also, diversity index and dominant index were decreased and increased with proceeding from middle part to lower part.

Fator de desacoplamento em um canavial irrigado no submédio do Vale do São Francisco

Objetivou-se, com este trabalho, analisar a interação da cana-de-açúcar irrigada com a atmosfera circunvizinha, por meio do fator de desacoplamento (Ω), para cinco períodos distintos de crescimento e entre eventos de irrigação. O estudo foi conduzido na região do Submédio do Vale do São Francisco. Os dados utilizados para a estimativa de Ω foram obtidos de sensores acomodados em uma torre micrometeorológica, instalada numa área experimental de cana-de-açúcar, no ciclo de cana-soca. Observou-se que no início do ciclo da cultura (70 a 95 dias após o corte, DAC), o valor médio de Ω foi 0,74 em decorrência de baixos valores da altura das plantas e do índice de área foliar, devido aos altos valores de velocidade do vento, que reduziram a interação entre a cana-de-açúcar e o ar circunvizinho. Contudo, valor similar foi verificado no período de 309 a 338 DAC, que ocorreu em parte da estação chuvosa, em virtude da evaporação da água depositada sobre o dossel vegetativo. Tanto o tombamento da cana-de-açúcar, ocorrido no período de 218 e 248 DAC, quanto à suspensão da irrigação, ao final do ciclo (339 a 378 DAC) promoveram redução nos valores médios de Ω (0,61 e 0,69, respectivamente).

Construction and Geometry Control of Incheon Cable-Stayed Bridge

The Incheon Bridge is a continuous span steel deck cable-stayed bridge with six traffic lanes in dual direction. Its total length is 1480 m including an 800 m centre span. The pylon was designed as an inverted Y-shaped concrete structure of 238 m in height. The pylon consists of four parts, namely the lower part, cross beam, middle part and upper cable anchorage part. The pylon was constructed by being divided into 57 lots of 4 m height, and auto-climbing form was applied. The cross beam was prefabricated at the factory to save construction time and was erected by using a floating crane. In order to control the geometry and secure the stability during construction, temporary tie and struts were installed and tensioned. For the superstructure erection, the side span was fabricated as four large blocks, which weighed 27 000 kN at the factory and was erected on temporary bents by using a 30 000 kN floating crane. The centre span was fabricated as a 15 m long block weighing 3000 kN and erected by a derrick crane along with the stay cables. A total of 208 cables were installed in a semi-fan shaped arrangement and four cables were stressed simultaneously. An integrated geometry control system was developed and applied for geometry control and cable adjustment during the erection. Four systems, namely, data integrated management system, structural analysis system, error adjustment system and measurement system, were employed. Approximately 6 to 7 days of cycle time was achieved for the superstructure erection within the allowable limits of geometry and cable tension. This paper presents the construction and geometry control system applied in the Incheon cable-stayed bridge.

The Cycle of Earnings Inequality: Evidence from Spanish Social Security Data

We use detailed information on labor earnings and employment from social security records to document the evolution of earnings inequality in Spain from 1988 to 2010. Male earnings inequality was strongly countercyclical: it increased around the 1993 recession, showed a substantial decrease during the 1997-2007 expansion, and then a sharp increase during the recent recession. This evolution was partly driven by the cyclicality of employment and earnings in the lower-middle part of the distribution. We emphasize the importance of the housing boom and subsequent housing bust, and show that demand shocks in the construction sector had large effects on aggregate labor market outcomes.

The Cycle of Earnings Inequality: Evidence from Spanish Social Security Data

We use detailed information on labor earnings and employment from Social Security records to document earnings inequality in Spain from 1988 to 2010. Male earnings inequality was strongly countercyclical: it increased around the 1993 recession, showed a substantial decrease during the 1997-2007 expansion and then a sharp increase during the recent recession. These developments were partly driven by the cyclicality of employment and earnings in the lower-middle part of the distribution. We emphasize the importance of the housing boom and subsequent housing bust, and show that demand shocks in the construction sector significantly impacted aggregate labor market outcomes.

SEA-LEVEL CHANGES RECORDED BY CERIUM ANOMALIES IN THE LATE JURASSIC (TITHONIAN) BLACK ROCK SERIES OF QIANGTANG BASIN, NORTH-CENTRAL TIBET

The Upper Jurassic black rock series of the Amdo area of north-central Tibet have attracted attention because of its organic-rich matter and oil seepage in the rock series. Abundant ammonites of Aulacosphinctes and Virgatosphinctes as well as bivalves including Buchia and Chlamys, are well preserved in the Qiangmuleiqu Formation of the Middle to Late Tithonian (Late Jurassic). The total rare earth elements (∑REE) abundance of the formation varies from 18.814 to 46.818 ppm and is lower than that of an average in marine shales. Inter-element correlations suggest that the shale-normalized REE patterns provide the information about the origin of sedimentary rocks (i.e., not affected by diagenesis), and can be used as a potential indicator for eustatic sea-level changes. The Ceanom values gradually increased from –0.015 to –0.238 from the lower to middle part of the series, indicating a rise in sea level. The Ceanom then dropped to –0.081, suggesting a lowering of sea level. From the middle to upper part of the section, there are two more sea-level fluctuations indicated by variations of cerium anomaly values. Thus, sea-level fluctuations occurred three times in this Late Jurassic section, with major episodes of eustatic rise took place in the lower-middle part of this section. These episodic cycles show