渤海南部海域沉积物-海水界面附近磷、硅赋存形态及其生物地球化学过程研究

本文系统研究了渤海南部海域沉积物-海水界面附近（包括上覆水、悬浮颗粒物和沉积物）P、Si的赋存形态及其生物地球化学过程。其特色在于提出了“自然粒度下形态研究”的概念，探讨了能真正参与循环的P、Si及其控制关键环节，为渤海资源特别是生物资源的可持续利用战略的制定提供理论基础。得到的主要结论包括：研究了渤海南部海域覆水、悬浮颗粒物中P、Si的变异特征。上覆水体PO_4-P、SiO_3-Si的平均含量均低于大洋底层水PO_4-P、SiO_3-Si的平均含量。悬浮颗粒物中TIP、BP的来源和循环控制机制不同，TISi、BSi有一定的相似性。稀释作用和表层沉积物中可交换态P、Si的循环控制上覆水体中P、Si的地球化学行为。颗粒物中TIP、TISi的行为受离子交换和化学吸附过程影响，其中化学吸附可能与Fe（III）的氧化物有关；生物过程对颗粒物中生源P、Si的地球化学行为有重要影响。渤海南部海域沉积物P、Si的分布特征及其成岩过程研究表明。表层沉积物可交换态磷中，OSF-P是磷的优势赋存形态，占总磷的10.7%；CF-Si是硅的优势赋存形态，占总硅的0.05%。 不同形态P的成岩过程有一定的相似性。TSi与其它相中的Si呈负相关或不呈显著相关，且可交换态Si的量仅占总Si的0.12%以下，说明以往采用测定总Si含量来研究Si的生物地球化学过程不可能得出有价值的信息。IMOF-P、OSF-P、IMOF-Si、CF-Si在P、Si的生物地球化学循环中有重要作用。CaCO_3、Fe（III）和Corg等对P、Si界面循环有重要影响，有机质的钙化导OSF-P的矿化作用而释放P；Fe（III）的还原引起IMOF-P， CF-P和CF-Si对P、Si的释放。Corg的成岩过程对CF-Si有影响。约79%的BP和75%的BSi沉积后转化为相对稳定状态，在较短时间内不再参与循环。柱状沉积物中，OSF-P和CF-P之间存在沉积转化。CF-Si呈双指数分布。P、Si在表层沉积物中垂向分布的差异，表明底栖生物扰动对加强界面P、Si交换的作用。室内模拟沉积物-海水界面附近P、Si交换过程表明，P、Si在沉积物、上覆海水间的交换通量分别为0.8μ mol/ (m~2 · h)。P、Si的埋藏与释放主要受OSF-P、IMOF-Si 和平共处BSi的影响。对渤海P、Si年循环的估算显示，P在渤海湾、莱州湾的年循环量达30.9 * 10~5kg 和13.8 * 10~5kg， Si则分别为22.8 * 10~7 kg和15.5 * 10~7 kg，这其中沉积物向上覆海水扩散的P占87.7%和87.0%， Si占22.4%和14.2%。就整个渤海而言，沉积物向海水释放的磷、硅在其总循环中分别占88.7%和34.0%，所以沉积物-海水界面过程对磷、硅在渤海的生物地球化学循环有重要影响，是渤海P、Si循环的关键控制过程之一。

叠前时间偏移：各向异性、多次波衰减及应用

At present, in order to image complex structures more accurately, the seismic migration methods has been developed from isotropic media to the anisotropic media. This dissertation develops a prestack time migration algorithm and application aspects for complex structures systematically. In transversely isotropic media with a vertical symmetry axis (VTI media), the dissertation starts from the theory that the prestack time migration is an approximation of the prestack depth migration, based on the one way wave equation and VTI time migration dispersion relation, by combining the stationary-phase theory gives a wave equation based VTI prestack time migration algorithm. Based on this algorithm, we can analytically obtain the travel time and amplitude expression in VTI media, as while conclude how the anisotropic parameter influence the time migration, and by analyzing the normal moveout of the far offset seismic data and lateral inhomogeneity of velocity, we can update the velocity model and estimate the anisotropic parameter model through the time migration. When anisotropic parameter is zero, this algorithm degenerates to the isotropic time migration algorithm naturally, so we can propose an isotopic processing procedure for imaging. This procedure may keep the main character of time migration such as high computational efficiency and velocity estimation through the migration, and, additionally, partially compensate the geometric divergence by adopting the deconvolution imaging condition of wave equation migration. Application of this algorithm to the complicated synthetic dataset and field data demonstrates the effectiveness of the approach. In the dissertation we also present an approach for estimating the velocity model and anisotropic parameter model. After analyzing the velocity and anisotropic parameter impaction on the time migration, and based on the normal moveout of the far offset seismic data and lateral inhomogeneity of velocity, through migration we can update the velocity model and estimate the anisotropic parameter model by combining the advantages of velocity analysis in isotropic media and anisotropic parameter estimation in VTI media. Testing on the synthetic and field data, demonstrates the method is effective and very steady. Massive synthetic dataset、2D sea dataset and 3D field datasets are used for VTI prestack time migration and compared to the stacked section after NMO and prestack isotropic time migration stacked section to demonstrate that VTI prestack time migration method in this paper can obtain better focusing and less positioning errors of complicated dip reflectors. When subsurface is more complex, primaries and multiples could not be separated in the Radon domain because they can no longer be described with simple functions (parabolic). We propose an attenuating multiple method in the image domain to resolve this problem. For a given velocity model，since time migration takes the complex structures wavefield propagation in to account, primaries and multiples have different offset-domain moveout discrepancies, then can be separated using techniques similar to the prior migration with Radon transform. Since every individual offset-domain common-reflection point gather incorporates complex 3D propagation effects, our method has the advantage of working with 3D data and complicated geology. Testing on synthetic and real data, we demonstrate the power of the method in discriminating between primaries and multiples after prestack time migration, and multiples can be attenuated in the image space considerably.

地震波阻抗反演的迭代正则化算法

Post-stack seismic impedance inversion is the key technology of reservoir prediction and identification. Geophysicists have done a lot of research for the problem, but the developed methods still cannot satisfy practical requirements completely. The results of different inversion methods are different and the results of one method used by different people are different too. The reasons are due to the quality of seismic data, inaccurate wavelet extraction, errors between normal incidence assumption and real situation, and so on. In addition, there are two main influence factors: one is the band-limited property of seismic data; the other is the ill-posed property of impedance inversion. Thus far, the most effective way to solve the band-limited problem is the constrained inversion. And the most effective way to solve ill-posed problems is the regularization method assisted with proper optimization techniques. This thesis systematically introduces the iterative regularization methods and numerical optimization methods for impedance inversion. A regularized restarted conjugate gradient method for solving ill-posed problems in impedance inversion is proposed. Theoretic simulations are made and field data applications are performed. It reveals that the proposed algorithm possesses the superiority to conventional conjugate gradient method. Finally, non-smooth optimization is proposed as the further research direction in seismic impedance inversion according to practical situation.

Minimizing Statistical Bias with Queries

I describe an exploration criterion that attempts to minimize the error of a learner by minimizing its estimated squared bias. I describe experiments with locally-weighted regression on two simple kinematics problems, and observe that this "bias-only" approach outperforms the more common "variance-only" exploration approach, even in the presence of noise.

An Algorithm for Group Formation and Maximal Independent Set in an Amorphous Computer

Amorphous computing is the study of programming ultra-scale computing environments of smart sensors and actuators cite{white-paper}. The individual elements are identical, asynchronous, randomly placed, embedded and communicate locally via wireless broadcast. Aggregating the processors into groups is a useful paradigm for programming an amorphous computer because groups can be used for specialization, increased robustness, and efficient resource allocation. This paper presents a new algorithm, called the clubs algorithm, for efficiently aggregating processors into groups in an amorphous computer, in time proportional to the local density of processors. The clubs algorithm is well-suited to the unique characteristics of an amorphous computer. In addition, the algorithm derives two properties from the physical embedding of the amorphous computer: an upper bound on the number of groups formed and a constant upper bound on the density of groups. The clubs algorithm can also be extended to find the maximal independent set (MIS) and $Delta + 1$ vertex coloring in an amorphous computer in $O(log N)$ rounds, where $N$ is the total number of elements and $Delta$ is the maximum degree.

Plano de exploração sob critérios de manejo florestal de baixo impacto.

A exploração florestal convencional infelizmente tem objetivos de curto prazo. O resultado final é uma diminuição da área útil de manejo com possibilidades de regeneração. Normas que contemplam uma intervenção de baixo impacto, em povoamento de floresta nativa, podem garantir uma maior certeza na sustentabilidade do manejo florestal.

Expression of C-reactive protein in human lung epithelial cells and up-regulation by cytokines and carbon particles.

C-reactive protein (CRP) is the prototypic human acute-phase protein and is found at increased levels in the blood during episodes of inflammation. CRP was generally thought to be produced only by hepatocytes; however, several studies have shown extrahepatic synthesis of CRP. A previous study showed that PM10 and ultrafine carbon black (ufCB) were able to induce CRP expression in A549 cells. This study aims to examine the factors that lead to the production of CRP in A549 cells. A549 human lung epithelial cells were treated with cytokines (interleukin 6, tumor necrosis factor , interferon , or interleukin 1) or carbon particles (CB and ufCB) for 18 h. It was found that CRP could be expressed within the cells and that CRP was secreted from the cells particularly with tumor necrosis factor , CB and ufCB treatments. It was also found that this expression of CRP with CB and ufCB treatments was dependent on nuclear factor kappa B (NFB). The expression of CRP in A549 cells may indicate an important role for CRP expression and secretion from lung epithelial cells in response to inflammatory stimuli.

Competitive advantage revisited: Michael Porter on strategy and competitiveness.

Strategic management is constantly evolving as both an academic discipline and as a reflection of management practice. This article, based on a recent interview with Michael Porter, assesses his contribution to the development of the discipline in the context of the advances that have taken place since the publication of his seminal work Competitive Strategy in 1980. The authors conclude that Porter has made major lasting contributions to strategy, increasing both its academic rigor and its accessibility to managers. The article and interview place Porter's work at the center of the development of strategic management in terms of the provision of practical analytical frameworks, transforming it into a recognized and recognizable field of academic study and management practice. This feat of transformation has not been equaled before or since, so that 25 years after his first seminal contribution, Porter's work continues to provide remarkable insights into the nature of competition and strategy.

Laser photoacoustic detection allows in planta detection of nitric oxide in tobacco following challenge with avirulent and virulent pseudomonas syringae pathovars

Luis A.J. Mur, I. Edi Santosa, Lucas J.J. Laarhoven, Nicholas J. Holton, Frans J.M. Harren and Aileen R. Smith (2005). Laser photoacoustic detection allows in planta detection of nitric oxide in tobacco following challenge with avirulent and virulent pseudomonas syringae pathovars. Plant Physiology, 138(3), 1247-1258. Sponsorship: BBSRC / EU RAE2008

Vidas de los varones ilustres del Monasterio de la Trapa

Signaturas: [ ]1, [*]4, [¶]-2[¶]4, 3[¶]8, A-Z4, 2A-2L4 ; [ ]2, A-Z4, 2A-2K4 ; [ ]2, A-Z4, 2A-2Q4.

Form, fi gure, and the experience of time in seven southern composers of the 1950s-60s

After the 1980s it is diffi cult, following stylistic criteria, to draw a map of contemporary academic music. All styles are compossible, and all are practiced. In this context, the geographical entity “South of Italy” does not stand out for a musical identity with special technical-stylistic features. Rather, at a socio-cultural level, the South remains today – in music no less than in all areas where there is a gap between top development and stagnation – a land of emigrants: six out of the seven composers treated (Ivan Fedele, Giuseppe Colardo, Rosario Mirigliano, Giuseppe Soccio, Nicola Cisternino, Biagio Putignano, Paolo Aralla) live in the North of Italy. The positive aspect of this is the affi nity of the South with the transnational and superstructural community of contemporary music, which from European and Western has now become almost global. The composers under consideration belong to the generation of the ‘50s, rooted in the serial and post-serial movements (from which Franco Donatoni, Luciano Berio, Luigi Nono, Salvatore Sciarrino, Giacinto Scelsi, are the principals models, to mention only the Italians), dipped in the general phenomenon of timbrism (particularly spectralism), and acquainted with electronics. They draw from these sources various instruments of compositional technique and aspects of their poetics. In particular these composers, active from the ‘80s, develop new ways of construction of the temporal form of music. They share the goal to establish a new continuity, different from the tonal one but at the same time transcending the serial and post-serial disintegration and fragmentation. The primary means to this end is a new enhancement of the category of fi gure, as a clear and distinct, recognizable aggregate of pitches, intervals, register, durations, timbre, articulation, dynamics, and texture. Each composer elaborates the atonal fi gural material in different ways, emphasizing one aspect or another. For example, Fedele (1953) is a master in the management of form per se, Colardo (1953) in the activation of disturbed harmonic effects, Mirigliano (1950) in the creation of a slight tension from the smallest vibrations of sound, Soccio (1950) in the set up of movement by means of accumulations and discharges of energy, Cisternino (1957) in a Cagean-Scelsian emphasis on sound as such, Putignano (1960) in the suspension of time through the succession and transformation of images, Aralla (1960) in the foundation of form from below, from the concreteness of sound.

PARAMETERS AFFECTING THE IMAGING AND DETECTION OF MICROBUBBLES IN BLOOD

Stabilized micron-sized bubbles, known as contrast agents, are often injected into the body to enhance ultrasound imaging of blood flow. The ability to detect such bubbles in blood depends on the relative magnitude of the acoustic power backscattered from the microbubbles (‘signal’) to the power backscattered from the red blood cells (‘noise’). Erythrocytes are acoustically small (Rayleigh regime), weak scatterers, and therefore the backscatter coefficient (BSC) of blood increases as the fourth power of frequency throughout the diagnostic frequency range. Microbubbles, on the other hand, are either resonant or super-resonant in the range 5-30 MHz. Above resonance, their total scattering cross-section remains constant with increasing frequency. In the present thesis, a theoretical model of the BSC of a suspension of red blood cells is presented and compared to the BSC of Optison® contrast agent microbubbles. It is predicted that, as the frequency increases, the BSC of red blood cell suspensions eventually exceeds the BSC of the strong scattering microbubbles, leading to a dramatic reduction in signal-to-noise ratio (SNR). This decrease in SNR with increasing frequency was also confirmed experimentally by use of an active cavitation detector for different concentrations of Optison® microbubbles in erythrocyte suspensions of different hematocrits. The magnitude of the observed decrease in SNR correlated well with theoretical predictions in most cases, except for very dense suspensions of red blood cells, where it is hypothesized that the close proximity of erythrocytes inhibits the acoustic response of the microbubbles.

dPAM: A Distributed Prefetching Protocol for Scalable Asynchronous Multicast in P2P Systems

We leverage the buffering capabilities of end-systems to achieve scalable, asynchronous delivery of streams in a peer-to-peer environment. Unlike existing cache-and-relay schemes, we propose a distributed prefetching protocol where peers prefetch and store portions of the streaming media ahead of their playout time, thus not only turning themselves to possible sources for other peers but their prefetched data can allow them to overcome the departure of their source-peer. This stands in sharp contrast to existing cache-and-relay schemes where the departure of the source-peer forces its peer children to go the original server, thus disrupting their service and increasing server and network load. Through mathematical analysis and simulations, we show the effectiveness of maintaining such asynchronous multicasts from several source-peers to other children peers, and the efficacy of prefetching in the face of peer departures. We confirm the scalability of our dPAM protocol as it is shown to significantly reduce server load.

The War Between Mice and Elephants

Recent measurement based studies reveal that most of the Internet connections are short in terms of the amount of traffic they carry (mice), while a small fraction of the connections are carrying a large portion of the traffic (elephants). A careful study of the TCP protocol shows that without help from an Active Queue Management (AQM) policy, short connections tend to lose to long connections in their competition for bandwidth. This is because short connections do not gain detailed knowledge of the network state, and therefore they are doomed to be less competitive due to the conservative nature of the TCP congestion control algorithm. Inspired by the Differentiated Services (Diffserv) architecture, we propose to give preferential treatment to short connections inside the bottleneck queue, so that short connections experience less packet drop rate than long connections. This is done by employing the RIO (RED with In and Out) queue management policy which uses different drop functions for different classes of traffic. Our simulation results show that: (1) in a highly loaded network, preferential treatment is necessary to provide short TCP connections with better response time and fairness without hurting the performance of long TCP connections; (2) the proposed scheme still delivers packets in FIFO manner at each link, thus it maintains statistical multiplexing gain and does not misorder packets; (3) choosing a smaller default initial timeout value for TCP can help enhance the performance of short TCP flows, however not as effectively as our scheme and at the risk of congestion collapse; (4) in the worst case, our proposal works as well as a regular RED scheme, in terms of response time and goodput.

Simulations of X and Y Retinal Ganglion Cell Behavior with a Nonlinear Push-pull Model of Spatiotemporal Retinal Processing

This article describes a nonlinear model of neural processing in the vertebrate retina, comprising model photoreceptors, model push-pull bipolar cells, and model ganglion cells. Previous analyses and simulations have shown that with a choice of parameters that mimics beta cells, the model exhibits X-like linear spatial summation (null response to contrast-reversed gratings) in spite of photoreceptor nonlinearities; on the other hand, a choice of parameters that mimics alpha cells leads to Y-like frequency doubling. This article extends the previous work by showing that the model can replicate qualitatively many of the original findings on X and Y cells with a fixed choice of parameters. The results generally support the hypothesis that X and Y cells can be seen as functional variants of a single neural circuit. The model also suggests that both depolarizing and hyperpolarizing bipolar cells converge onto both ON and OFF ganglion cell types. The push-pull connectivity enables ganglion cells to remain sensitive to deviations about the mean output level of nonlinear photoreceptors. These and other properties of the push-pull model are discussed in the general context of retinal processing of spatiotemporal luminance patterns.