Occurrence patterns of alien freshwater turtles in a large urban pond ‘Archipelago’ (Rome,Italy): Suggesting hypotheses on root causes

The patterns of the occurrence and distribution of alien freshwater turtle species in an urban pond archipelago (Rome, Italy) were analysed, with the aim of exploring the role of a set of factors (type of ponds, landscape context, size area, distance from the nearest road) with a generalized linear model approach. A total of 311 ponds subdivided in three types (fountains, small basins, lakes) embedded in different landscape contexts (public parks, private parks, urban areas) at differing distances from the nearest road were sampled. Six non‐native freshwater turtle species in 31 sites were recorded (9.97%). Lakes exhibited the highest occurrence rates of alien freshwater turtles, compared to small basins and fountains. Freshwater turtle species in urbanized areas were only observed in parks (both public and private). In both the public and private parks, the lakes exhibited the highest percentage of occupied sites, with fountains being the lowest. A direct and significant relationship was observed between pond size and species richness. The distance from the nearest road did not appear to affect species richness. A first interpretation of the data from this study facilitated the postulation of two a posteriori hypotheses that should be tested, as follows: (i) the causal process of turtle release is random, and the rate of extinction (and recapture) is higher in smaller ponds, thus producing the observed pattern; and (ii) the turtle release is not random, and people actively select the ponds they consider more suitable for their pet animals. In this study, it appears the lakes were perceived by those who abandon their pets as the most ecologically suitable habitats among other pond types to accommodate the different species of turtles. Knowledge of people's attitudes in regard to releasing pet animals also might assist managers of public green spaces to develop strategies aimed to preserve local biodiversity, and to educate the public about the conservation issue represented by the alien species.     

地震地貌学在L区浊积砂体预测中的应用

地震地貌学是一种新的地震相分析与表征方法,研究的是沉积特征在沉积等时面上的地震映像。它与地震岩石学一起构成了地震沉积学的主体。以L区为例,介绍了地震地貌学方法的基本工作流程、关键技术及其在沉积分析和储层预测方面的应用。地震地貌学强调在相对地质年代域中对沉积体成像,表征了地震相的平面反射形态。通过地震地貌学的沉积解释,容易把控沉积体的展布范围及其在沉积体系中的发育部位。沉积体的地震地貌学解释结果反投影到反演剖面上,可实现相控下的砂体雕刻,使属性分析和反演达到有机结合,从而提高沉积体和储层的预测精度。     

大型咸化湖盆地层岩性油气藏有利条件与勘探方向——以柴达木盆地柴西南古近纪为例

柴达木盆地古近纪—新近纪经历了多期构造运动、古气候由温湿向干旱演变、湖盆逐渐咸化、沉积中心由西向东迁移的演化过程,地层岩性油气藏的主控因素和发育特征有其特殊规律,以柴达木盆地柴西南富油气凹陷精细勘探区带为重点,通过分析烃源岩展布、沉积演化和主要沉积体系展布,提出咸化湖盆在河流入湖后因密度差较大,易形成密度流等成因的各类滩坝砂体,最大湖泛面之下的高位体系域、湖侵体系域是地层岩性油气藏的主要勘探领域。柴西南古近纪斜坡背景为岩性油气藏提供了基本成藏条件,构造宽缓带和鼻隆带有利于形成地层岩性油气藏,构造背景和砂体成因决定了局部的油气富集,斜坡背景上的宽缓平台区是源下、源内岩性油气藏的主要富集区。地层岩性油气藏的勘探重点是咸化湖盆的各类滩坝砂体、湖侵体系域的滨浅湖滩坝砂体、扇三角洲和三角洲前缘的各类较孤立的砂体,滨浅湖带广泛分布的藻灰岩也是岩性油气藏的重要勘探方向。     

齐家—鸳鸯沟地区沙河街组油气富集规律研究

针对油气勘探中存在的油水关系复杂问题,采用油气藏解剖和油气分布与成藏条件之间的空间匹配关系,对齐家—鸳鸯沟地区沙河街组油气富集规律及控制因素进行了研究,结果表明:齐家—鸳鸯沟地区油气在纵向上主要分布在沙二段,平面上主要分布在Ⅲ号台阶上,并以断层-岩性油气藏类型居多;油气富集主要受到砂体储层是否发育、圈闭是否发育、断层侧向封闭性强弱、断裂后期活动性强弱4个因素的控制;不同层段油气富集的主控因素不同,沙二段、沙三1亚段和沙四段圈闭不发育是造成失利井的最主要原因,而沙三2亚段和沙三3亚段砂体储层不发育也是造成失利井的最主要原因。     

A NOTE ON THE NARROW OPEN CHANNEL RESONANCE

1. INTRODUCTIONIt is well known that in a closed basin or in a harbor with a narrow entrance, resonance will occur when the external exciting frequencies are close to the standing wave frequenies in the harbor. Near the resonant frequency, a relative weak…     

高水头下不良地质体防渗补强技术研究与应用

针对200 m以上水头下复杂不良地质体的防渗补强技术难题,研发了高强度、高浸润渗透性、高粘结性、可操作时间长、胶凝时间精确可调和环保性能优良的CW系高性能环氧树脂灌浆材料,开发了针对不同受灌体和灌浆工况的水泥-化学复合灌浆精细控制工艺和配套灌浆设备,并形成了高水头下不良地质体处理成套技术。该技术已成功应用于溪洛渡、向家坝、清远抽水蓄能等重点水利水电工程,也可推广应用到交通、矿山等行业,具有广阔的应用前景。     

An Apoptotic Body-based Vehicle with Navigation for Photothermal-Immunotherapy by Precise Delivery and Tumor Microenvironment Regulation

Tumor precision therapy and preventing tumor recurrence and metastasis are the main challenges to tumor eradication. Herein, an apoptotic body-based vehicle with imaging navigation is developed for precise tumor delivery and photothermal-immunotherapy by IR820-conjugated apoptotic body loaded with R848 nanoparticles. The apoptotic body serves as ammunition stores as well as vehicle drive engines, while IR820 acts as a fluorescence imaging navigation and photothermal controlling system. The apoptotic body vehicle can deliver the ammunition to tumor and achieve deep penetration by macrophage-hitchhiking. Fluorescence imaging navigation opens a control window for photothermal treatment, followed by photothermal triggering of in situ vaccine formation. Further, CD47 antibody loaded hydrogel strengthens innate and adaptive immunity, simultaneously the polarization of macrophages regulates the immunosuppressive microenvironment to further promote the combined antitumor immunotherapy. With breast tumor (4T1)-bearing mice model, the apoptotic body vehicle performs excellent therapeutic efficacy for primary tumor, distant tumor, tumor metastasis, and recurrence prevention.     

Low-frequency scattering from perfectly conducting spheroidal bodies in a conductive medium with magnetic dipole excitation

Inductive electromagnetic means that are currently employed in the exploration of the Earth’s subsurface and embedded voluminous bodies often call for an intensive use, primary at the modeling stage and later on at the inversion stage, of analytically demanding tools of field calculation. Under the aim of modeling implementation, this contribution is concerned with some interesting aspects of the low-frequency interaction of arbitrarily orientated (i.e. three-dimensional) time-harmonic magnetic dipoles, with 3-D perfectly conducting spheroidal bodies embedded in an otherwise homogeneous conductive medium. For many practical applications involving buried obstacles such as Earth’s subsurface electromagnetic probing at low-frequency or any other physical cases (e.g. geoelectromagnetics), non-axisymmetric spheroidal geometry approximates sufficiently such kind of metallic shapes. On the other hand, our analytical approach deals with prolate spheroids, since the corresponding results for the oblate spheroidal geometry can be readily obtained through a simple transformation. The particular physical model concerns a solid impenetrable (metallic) body under a magnetic dipole excitation, where the scattering boundary value problem is attacked via rigorous low-frequency expansions for the incident, scattered and total electric and magnetic fields in terms of positive integral powers of (ik), that is (ik)ⁿ for n ? 0, where k stands for the complex wavenumber of the exterior medium. The purpose of the modeling is to contribute to a simple yet versatile tool to infer information on an unknown body from measurements of the three-component electric and magnetic fields nearby. Our goal is to obtain the most important terms of the low-frequency expansions of the electromagnetic fields, that is the static (for n = 0) and the dynamic (n = 1, 2, 3) terms. In particular, for n = 1 there are no incident fields and thus no scattered ones, while for n = 0 the Rayleigh electromagnetic expression is easily obtained in terms of infinite series. Emphasis is given on the calculation of the next two non-trivial terms (at n = 2 and at n = 3) of the aforementioned fields. Consequently, those are found in closed form from exact solutions of coupled (at n = 2, to the one at n = 0) or uncoupled (at n = 3) Laplace equations and they are given in compact fashion, as infinite series expansions for n = 2 or finite forms for n = 3. Nevertheless, the difficulty of the Poisson’s equation that has to be solved for n = 2 is presented, whereas our analytical approach demands the use of the well-known cut-off method in order to obtain an analytical closed solution. Finally, this research adds useful reference results to the already ample library of scattering by simple shapes using analytical methods.     

平面机械系统运动学的分析方法

本文介绍一种机械系统运动学分析的通用方法。文中根据多刚体系统运动学的原理,建立了受约束机械系统的运动约束方程、速度方程及加速度方程,还详细推导了以铰接副及滑动副连接的两邻接刚体的雅可比矩阵和加速度方程右边项,以求进一步说明本方法。文后还给出了实例。     

Some Open Problems in Dynamic Analysis of Flexible Multibody Systems

Some open questions arising in the dynamical formulation ofsystems of hinge-connected flexible bodies are discussed. The first one deals with the choice of the floating reference frame associated to abody undergoing large rigid body motions but small elastic deformations.The second one concerns the so-called geometric stiffening (orcentrifugal stiffening) effects. The last problem is concerned with theeventual appearance of higher-order terms in the kinetic energy of thesystem for large rates and large accelerations.