The effects of beach nourishment on the sandy-beach amphipod Exoediceros fossor: impact and recovery in Botany Bay, New South Wales, Australia

Beach nourishment is increasingly being implemented to address problems of erosion. However, the ecological consequences of nourishment are poorly understood, especially in Australia. In Botany Bay, sand was piped from an intertidal borrow area at Elephant's Trunk to nourish the nearby eroding beach at Towra Point. The effects on an intertidal exoedicerotid amphipod, Exoediceros fossor (Stimpson, 1856), were examined using a beyond-BACI (Before–After, Control–Impact) sampling design. Sampling was conducted before and after engineering operations at sites within the borrow and nourishment locations and multiple control locations. Hypotheses concerning impact and recovery were tested using asymmetrical ANOVAs and two-tailed F-tests. These examined the effects on abundance and spatial variability, respectively. The impact of the engineering operations on abundance was very large at both borrow and nourishment locations. However, recovery started within several weeks and, using space × time interactions as a criterion, appeared to be complete within a year. This conclusion is made cautiously because of low statistical power and because other criteria for recovery suggest that it was not complete at some sites. As beach erosion is likely to increase in severity with rising sea levels and greater storm surges associated with climate change, management authorities will need a better understanding of the ecological effects of beach nourishment.     

Oscillations of galactic cosmic rays and solar indices before the arrival of relativistic solar protons

Using modern wavelet analysis techniques, we have made an attempt to search for oscillations of intensity of galactic cosmic rays (GCR), sunspot numbers (SS) and magnitudes of coronal index (CI) implying that the time evolution of those oscillations may serve as a precursor of Ground Level Enhancements (GLEs) of solar cosmic rays (SCR). From total number of 70 GLEs registered in 1942–2006, the four large events — 23 February 1956, 14 July 2000, 28 October 2003, and 20 January 2005 — have been chosen for our study. By the results of our analysis, it was shown that a frequency of oscillations of GCR decreases as time approaches to the event day. We have also studied a behaviour of common periodicities of GCR and SCR within the time interval of individual GLE. The oscillations of GLE occurrence rate (OR) at different stages of the solar activity (SA) cycle is of special interest. We have found some common periodicities of SS and CI in the range of short (2.8, 5.2, 27 and 60 days), medium (0.3, 0.5, 0.7, 1.3, 1.8 and 3.2 years) and long (4.6 and 11.0 years) periods. Short and medium periodicities, in general, are rather concentrated around the maxima of solar cycles and display the complex phase relations. When comparing these results with the behaviour of OR oscillations we found that the period of 11 years is dominating (controlling); it is continuous over the entire time interval of 1942–2006, and during all this time it displays high synchronization and clear linear ratios between the phases of oscillations of η, SS and CI. It implies that SCR generation is not isolated stochastic phenomena characteristic exclusively for chromospheric and/or coronal structures. In fact, this process may have global features and involve large regions in the Sun’s atmosphere.     

Origin of magnetic minerals and natural remanent magnetization of basaltic rocks from Lower Silesia,Poland

Summary Two groups of basaltic rocks with normal and reversed NRM were examined. It was found that in both groups the primary NRM, synchronous with the period of rock formation, is preserved. Relations of the primary NRM to the origin and the degree of oxidation of magnetic minerals were considered in detail.     

Concerning the multiscale structure of solar convection

The discrete scale spectrum of the convective flows observed on the Sun has not yet received a convincing explanation. Here, an attempt is made to find conditions for the coexistence of convective flows on various scales in a horizontal fluid layer heated from below, where the thermal diffusivity varies with temperature in such a way that the static temperature difference across a thin sublayer near the upper surface of the layer is many times larger than the temperature variation across the remainder of the layer. The equations of two-dimensional thermal convection are solved numerically in an extended Boussinesq approximation, which admits thermal-diffusivity variations. The no-slip conditions are assumed at the lower boundary of the layer; either no-slip or free-slip conditions, at the upper boundary. In the former case, stable large-scale rolls develop, which experience small deformations under the action of small structures concentrated near the horizontal boundaries. In the latter case, the flow structure is highly variable, different flow scales dominate at different heights, the number of large rolls is not constant, and a sort of intermittency occurs: the enhancement of the small-scale flow component is frequently accompanied by the weakening of the large-scale one, and vice versa. The scale-splitting effects revealed here should manifest themselves in one way or another in the structure of solar convection.     

利用NOAA NDVI数据集监测冬小麦生育期的研究

探索了利用NDVI研究作物生育期的方法，对黄淮海冬麦区的返青期、抽穗期、成熟期进行了估测，并利用地面实际观测资料进行了验证。结果表明，NDVI数据对大范围农作物生育期监测是可行的。冬小麦遥感反青期由南到北依次推迟，符合春季绿波由南到北推移规律。对冬小麦遥感生育期年际变化分析表明，黄淮海平原返青期变化相对较大，而抽穗期和成熟期变化较小。根据历年月平均温度与返青期分析，冬小麦返青日期与2月份平均温度密切相关。对于局部地区，利用5d合成1km分辨率数据，且按农业生态分区分别制定生育期判别标准，估测效果将更好。     

西格陵兰Disko湾表层沉积硅藻组合研究

本文分析了西格陵兰Disko湾的表层沉积物硅藻,发现并统计了分属于39个属的78个硅藻种及其变种。应用对应分析方法,对Disko湾表层沉积硅藻组合进行了分类:组合Ⅰ为Fragilariopsis cylindrus-Fragilariopsis oceanica组合,主要分布在西格陵兰Disko湾南部的近岸和外海处;组合Ⅱ为Detonula confervaceae休眠孢子-Thalassiosira nordenskioeldii组合,都分布在Dis-ko湾北部海域。其中,根据海流等环境要素的不同,组合Ⅰ又可进一步划分为两个亚区:组合Ⅰa为F.cylindrus-F.oceanica-Pauliella taeniata组合,主要分布于沿岸海区;组合Ⅰb为F.cy-lindrus-F.oceanica-Thalassiosira antarcticavar.borealis休眠孢子-Thalassiosiracf.antarcticavar.borealis组合,分布于外海区域。     

Magnetization properties of intrusive/extrusive rocks from East Maio (Republic of Cape Verde) and their geological implications

Summary. The remanent magnetization of intrusive/extrusive rocks of the 'basement' complex of East Maio constitutes four components that define two different axes of magnetization, at around dec. 328, inc. 12 and dec. 007, inc. 14 respectively. In general, two or more components co-exist in separate specimens or sites but both axes are present most frequently in the normal sense. The NNW-striking axis, the B-axis, fits very well with the Upper Cretaceous polar wander path for Africa. It is consequently inferred that the major phase of sheet intrusions in Maio dates from this time, probably from the interval 90–70 Myr bp. Comparisons of the directional dispersions in the folded and unfolded states suggest that this injection phase post-dates the uplift of the Central Igneous Complex of the island. The second axis of magnetization, the A -axis, agrees very well with late Teritary—Quaternary palaeomagnetic data for Africa and the Canary Islands. The A -axis is therefore regarded as of secondary origin, being the consequence of a thermal/ chemical overprint during the Miocene—Pliocene volcanism on the island. The occurrence of a 50–70 Myr long period of volcanic quiescence and erosion, between the termination of the early igneous activity (Upper Cretaceous) and the rejuvenated magmatism in Miocene/Pliocene time, is compatible with similar observations in the Canary Islands. In contrast to the palaeomagnetic conclusions, the K/Ar data only give ages around 10 Myr. The unusually young isotope dates are regarded as being due to an almost complete age resetting and are seen in conjuction with the overprinted magnetization. This explanation is further supported by the fact that K/Ar results of pillow lavas underlying Upper Jurassic limestones only give Tertiary ages.     

Conversion between solid and beam element solutions of finite element method based on meta-modeling theory: development and application to a ramp tunnel structure

In this study, a new method for conversion of solid finite element solution to beam finite element solution is developed based on the meta-modeling theory which constructs a model consistent with continuum mechanics. The proposed method is rigorous and efficient compared to a typical conversion method which merely computes surface integration of solid element nodal stresses to obtain cross-sectional forces. The meta-modeling theory ensures the rigorousness of proposed method by defining a proper distance between beam element and solid element solutions in a function space of continuum mechanics. Results of numerical verification test that is conducted with a simple cantilever beam are used to find the proper distance function for this conversion. Time history analysis of the main tunnel structure of a real ramp tunnel is considered as a numerical example for the proposed conversion method. It is shown that cross-sectional forces are readily computed for solid element solution of the main tunnel structure when it is converted to a beam element solution using the proposed method. Further, envelopes of resultant forces which are of primary importance for the purpose of design, are developed for a given ground motion at the end.     

Evaluation of a multi-model approach to estimate leaf wetness duration: an essential input for disease alert systems

Theoretical and Applied Climatology - Disease alert systems (DAS) of the AgroClimate platform are intended to facilitate grower decision-making when planning fungicide applications. These DAS...     

Late Quaternary Evolution of Amvrakikos Gulf,Western Greece

Amvrakikos Gulf is a Neogene basin, formed during a late extensional tectonic phase within the Plio-Quaternary period. It is a semienclosed embayment, separated from the Ionian Sea by a shallow (< 10 m) channel. The analysis of 3.5-kHz seismic reflection profiles shows that, during the last (Würm) glacial period, the parts of the Gulf that lie at water depths >41 m (below present sea level) were a paleo-lake while the rest were exposed to subaerial erosion. Subsequent offshore depositional sequences accumulated at rates of 1.2–2.3 m/ka.