Research on the parameter inversion problem of prestack seismic data based on improved differential evolution algorithm

The parameter inversion technology composed by intelligent algorithm and AVO inversion for prestack seismic data provides a comparatively effective identification method for oil-gas exploration. However, traditionally intelligent iterative algorithm, such as, genetic algorithm, shows many disadvantages in solving this problem, including highly depending on initial model, fast convergence in algorithm and being easy to fall into local optimal. Therefore, an unsatisfied inversion performance is produced. In order to solve the above problems, this paper proposes a parameter inversion method based on improved differential evolution algorithm which is better in solving parameter inversion problems of prestack seismic data. In the proposed algorithm, aims at the Aki and Rechard approximation formula used specific initialization strategy, then the initialization parameter curve more smooth. Otherwise, the new algorithm has many advantages, such as, fast computing speed, simple operation, a low independence to initial model and good global convergence, this algorithm is the right choice in solving the parameter inversion problem based on pre-stack seismic data of real number encoding.     

Mechanical Property Characterization of Bilayered Tablets using Nondestructive Air-Coupled Acoustics

A noncontact/nondestructive air-coupled acoustic technique to be potentially used in mechanical property determination of bilayer tablets is presented. In the reported experiments, a bilayer tablet is vibrated via an acoustic field of an air-coupled transducer in a frequency range sufficiently high to excite several vibrational modes (harmonics) of the tablet. The tablet vibrational transient responses at a number of measurement points on the tablet are acquired by a laser vibrometer in a noncontact manner. An iterative computational procedure based on the finite element method is utilized to extract the Young’s modulus, the Poisson’s ratio, and the mass density values of each layer material of a bilayer tablet from a subset of the measured resonance frequencies. For verification purposes, a contact ultrasonic technique based on the time-of-flight data of the longitudinal (pressure) and transverse (shear) acoustic waves in each layer of a bilayer tablet is also utilized. The extracted mechanical properties from the air-coupled acoustic data agree well with those determined from the contact ultrasonic measurements. The mechanical properties of solid oral dosage forms have been shown to impact its mechanical integrity, disintegration profile and the release rate of the drug in the digestive tract, thus potentially affecting its therapeutic response. The presented nondestructive technique provides greater insight into the mechanical properties of the bilayer tablets and has the potential to identify quality and performance problems related to the mechanical properties of the bilayer tablets early on the production process and, consequently, reduce associated cost and material waste.     

Acoustic estimation of wildlife abundance: methodology for vocal mammals in forested habitats

Habitat loss and hunting pressure threaten mammal populations worldwide, generating critical time constraints on trend assessment. This study introduces a new survey method that samples continuously and non‐invasively over long time periods, obtaining estimates of abundance from vocalization rates. We present feasibility assessment methods for acoustic surveys and develop equations for estimating population size. As an illustration, we demonstrate the feasibility of acoustic surveys for African forest elephants (Loxodonta africana cyclotis). Visual surveys and vocalizations from a forest clearing in the Central African Republic were used to establish that low‐frequency elephant calling rate is a useful index of elephant numbers (linear regression P < 0.001, r_adj.² = 0.58). The effective sampling area was 3.22 km² per acoustic sensor, a dramatic increase in coverage over dung survey transects. These results support the use of acoustic surveys for estimating elephant abundance over large remote areas and in diverse habitats, using a distributed network of acoustic sensors. The abundance estimation methods presented can be applied in surveys of any species for which an acoustic abundance index and detection function have been established. This acoustic survey technique provides an opportunity to improve management and conservation of many acoustically‐active taxa whose populations are currently under‐monitored.     

A study of the hygienic aspects of the pedagogic process

A knowledge of the laws governing changes in the functional state of the organism of pupils during lessons at school is one of the principal bases for solving the hygienic problems of organizing the teaching. The main concern is the dynamics of changes in the actual functional state of the CNS as a result of a whole complex of endogenous and exogenous factors as well as the school work of the pupil itself. Changes in the functional state of the optic and acoustic analysors deserve special attention in this respect because of their great exposure in pedagogical work. The existing interindividual differences in performance and in the work rate of pupils should be solved by an adequate pedagogical approach. Correct use of the principle of differentiated tuition can be a positive contribution to solving some of the topical problems of hygiene of the pedagogical process.     

Green plants as intelligent organisms

Intelligent behaviour, even in humans, is an aspect of complex adaptive behaviour that provides a capacity for problem solving. This article assesses whether plants have a capacity to solve problems and, therefore, could be classified as intelligent organisms. The complex molecular network that is found in every plant cell and underpins plant behaviour is described. The problems that many plants face and that need solution are briefly outlined, and some of the kinds of behaviour used to solve these problems are discussed. A simple way of comparing plant intelligence between two genotypes is illustrated and some of the objections raised against the idea of plant intelligence are considered but discarded. It is concluded that plants exhibit the simple forms of behaviour that neuroscientists describe as basic intelligence.     

中国植物遗传连锁图谱构建研究进展

遗传连锁图谱构建是基因组研究中的重要环节,是基因定位与克隆乃至基因组结构与功能研究的基础上。近十几年来,分子生物学特别是分子标记技术的飞速发展,为构建高饱和的植物遗传连锁图谱和利用分子标记进行辅助育种奠定了基础。综述了我国在植物遗传连锁图谱构建研究方面的进展及发展动态,列举了我国利用DNA分子标记构建的34张植物遗传连锁图谱实例,且讨论了当前我国在该领域研究中存在的问题并提出了解决途径。     

A linear programming approach for identifying a consensus sequence on DNA sequences

MOTIVATION: Maximum-likelihood methods for solving the consensus sequence identification (CSI) problem on DNA sequences may only find a local optimum rather than the global optimum. Additionally, such methods do not allow logical constraints to be imposed on their models. This study develops a linear programming technique to solve CSI problems by finding an optimum consensus sequence. This method is computationally more efficient and is guaranteed to reach the global optimum. The developed method can also be extended to treat more complicated CSI problems with ambiguous conserved patterns. RESULTS: A CSI problem is first formulated as a non-linear mixed 0-1 optimization program, which is then converted into a linear mixed 0-1 program. The proposed method provides the following advantages over maximum-likelihood methods: (1) It is guaranteed to find the global optimum. (2) It can embed various logical constraints into the corresponding model. (3) It is applicable to problems with many long sequences. (4) It can find the second and the third best solutions. An extension of the proposed linear mixed 0-1 program is also designed to solve CSI problems with an unknown spacer length between conserved regions. Two examples of searching for CRP-binding sites and for FNR-binding sites in the Escherichia coli genome are used to illustrate and test the proposed method. AVAILABILITY: A software package, Global Site Seer for the Microsoft Windows operating system is available by http://www.iim.nctu.edu.tw/~cjfu/gss.htm     

The possibility of computer analysis of the twilight soundscape of the orthopteran (Tettigoniidae,Gryllidae) community,by the example of an agrocenosis in Eastern Bulgaria

Computer analysis of the twilight soundscape with the sounds of grasshoppers (Tettigoniidae) and crickets (Gryllidae) recorded in an agrocenosis of Eastern Bulgaria was performed. Seven species were identified by the dynamic spectrograms. It is shown that analysis of the group stridulation spectrograms of Ensifera can be useful not only for solving ecological and faunistic problems but also for studying the acoustic interactions of conspecific and heterospecific individuals in the same biotope.     

On the complexity of fundamental computational problems in pedigree analysis.

Pedigree analysis is a central component of many current efforts to locate genes that contribute to diseases or to valuable traits. The analysis usually involves solving one of two very computation-intense problems. We analyze the complexity of these two problems. Surprisingly, we show that both problems are NP-hard even for pedigrees that contain no inbreeding loops.     

高强度聚焦超声可治疗区域的仿真研究

数值仿真不同治疗参数条件下高强度聚焦超声(high intensity focused ultrasound,HIFU)可治疗区域的变化,对HIFU治疗剂量的确定具有重要的指导意义。本文采用Westervelt方程的近似式,结合Pennes生物热传导方程,以离体猪肝组织为例,在考虑组织声学特性对HIFU焦域温度场影响的条件下,通过时域有限差分法(finite difference time domain,FDTD)对HIFU焦域温度场进行仿真研究。研究结果表明,照射时间越长,组织声学特性的影响就越明显;焦点处的最高温升相同时,可治疗区域的大小差异较小;声强越大,形成可治疗区域所需的时间也越短;当声强一定时,随着照射时间的增加,可治疗区域的长、短轴长度均呈非线性增加;在相同可治疗区域的长轴或短轴长度一定时,输入声强和照射时间呈负相关。     

Temporal dynamics of mental impasses underlying insight-like problem solving

Insight problem solving is characterized by mental impasses,states of mind in which the problem solver does not know what to do next.Although many studies have investigated the neural correlates of insight problem solving,however,the question when mental impasses occur during insight problem solving has been rarely studied.The present study adopted high temporal resolution ERPs to investigate the temporal dynamics of an impasse underlying insight problem solving.Time locked ERPs were recorded associated with problems with impasses(PWI) and problems without impasses(POI).The problem types were determined by participants’ subjective responses.The results revealed an early frontocentral P2 was linked with the preconscious awareness of mental impasses and a P3a was associated with fixed attention when the impasse formed.These findings suggest the impasse may occur initially at a relatively early stage and metacognition plays an important role in insight problem solving.     

同步PCR技术及其在植物核酸分子定量中的应用

同步PCR是一种集生化、光电和计算机技术于一体的封闭式DNA扩增系统,采用荧光染料将扩增与检测过程结合在一起,实现了在PCR过程中在线显示PCR反应,通过检测荧光强度来绝对定量起始模板的拷贝数。该技术大大简化和加速了核酸分子的定量过程,不仅快速、灵敏、准确、重复性好,而且很容易计算出待测样品中核酸分子的绝对起始拷贝数。同微阵列等分子生物技术一起,同步PcR技术将会在功能基因解析和病害分子诊断等方面发挥重要作用。本综述除了介绍同步．PCR技术的原理和应用外,还介绍了定量拟南芥,Aux／正4,4基因的转录水平的实验,并就同步PCR操作过程中的问题进行了讨论。     

Severity-Based Adaptation with Limited Data for ASR to Aid Dysarthric Speakers

Automatic speech recognition (ASR) is currently used in many assistive technologies, such as helping individuals with speech impairment in their communication ability. One challenge in ASR for speech-impaired individuals is the difficulty in obtaining a good speech database of impaired speakers for building an effective speech acoustic model. Because there are very few existing databases of impaired speech, which are also limited in size, the obvious solution to build a speech acoustic model of impaired speech is by employing adaptation techniques. However, issues that have not been addressed in existing studies in the area of adaptation for speech impairment are as follows: (1) identifying the most effective adaptation technique for impaired speech; and (2) the use of suitable source models to build an effective impaired-speech acoustic model. This research investigates the above-mentioned two issues on dysarthria, a type of speech impairment affecting millions of people. We applied both unimpaired and impaired speech as the source model with well-known adaptation techniques like the maximum likelihood linear regression (MLLR) and the constrained-MLLR(C-MLLR). The recognition accuracy of each impaired speech acoustic model is measured in terms of word error rate (WER), with further assessments, including phoneme insertion, substitution and deletion rates. Unimpaired speech when combined with limited high-quality speech-impaired data improves performance of ASR systems in recognising severely impaired dysarthric speech. The C-MLLR adaptation technique was also found to be better than MLLR in recognising mildly and moderately impaired speech based on the statistical analysis of the WER. It was found that phoneme substitution was the biggest contributing factor in WER in dysarthric speech for all levels of severity. The results show that the speech acoustic models derived from suitable adaptation techniques improve the performance of ASR systems in recognising impaired speech with limited adaptation data.     

Nanotechnology and pharmaceutical inhalation aerosols

Pharmaceutical inhalation aerosols have been playing a crucial role in the health and well being of millions of people throughout the world for many years. The technology's continual advancement, the ease of use and the more desirable pulmonary-rather-than-needle delivery for systemic drugs has increased the attraction for the pharmaceutical aerosol in recent years. But administration of drugs by the pulmonary route is technically challenging because oral deposition can be high, and variations in inhalation technique can affect the quantity of drug delivered to the lungs. Recent advances in nanotechnology, particularly drug delivery field have encouraged formulation scientists to expand their reach in solving tricky problems related to drug delivery. Moreover, application of nanotechnology to aerosol science has opened up a new category of pharmaceutical aerosols (collectively known as nanoenabled-aerosols) with added advantages and effectiveness. In this review, some of the latest approaches of nano-enabled aerosol drug delivery system (including nano-suspension, trojan particles, bioadhesive nanoparticles and smart particle aerosols) that can be employed successfully to overcome problems of conventional aerosol systems have been introduced.     

大学生微生物学实验技能培养的研究

针对我国高校目前比较普遍地存在的应届大学毕业生微生物学实验技能不够强、解决实际问题能力差的突出问题,分析了问题产生的主要原因和解决该问题的重要意义,提出了解决此问题的多方面的具体措施和多年实践的初步结果。     

Extending bioacoustic monitoring of birds aloft through flight call localization with a three‐dimensional microphone array

Bioacoustic localization of bird vocalizations provides unattended observations of the location of calling individuals in many field applications. While this technique has been successful in monitoring terrestrial distributions of calling birds, no published study has applied these methods to migrating birds in flight. The value of nocturnal flight call recordings can increase with the addition of three‐dimensional position retrievals, which can be achieved with adjustments to existing localization techniques. Using the time difference of arrival method, we have developed a proof‐of‐concept acoustic microphone array that allows the three‐dimensional positioning of calls within the airspace. Our array consists of six microphones, mounted in pairs at the top and bottom of three 10‐m poles, arranged in an equilateral triangle with sides of 20 m. The microphone array was designed using readily available components and costs less than $2,000 USD to build and deploy. We validate this technique using a kite‐lofted GPS and speaker package, and obtain 60.1% of vertical retrievals within the accuracy of the GPS measurements (±5 m) and 80.4% of vertical retrievals within ±10 m. The mean Euclidian distance between the acoustic retrievals of flight calls and the GPS truth was 9.6 m. Identification and localization of nocturnal flight calls have the potential to provide species‐specific spatial characterizations of bird migration within the airspace. Even with the inexpensive equipment used in this trial, low‐altitude applications such as surveillance around wind farms or oil platforms can benefit from the three‐dimensional retrievals provided by this technique.     

A critical race theory approach to black American entrepreneurship

ABSTRACT

In recent years, a growing literature has suggested that self-employment is a viable means of solving economic problems for a wide range of groups who are subject to poverty, discrimination and other disadvantages. Yet African Americans have not developed an ethnic economy large enough to solve many of their economic problems. To explore the question, this paper reviews three of the most common explanations for black Americans’ low rates of entrepreneurship: the cultural/psychological perspective, the ethnic enterprise perspective and the critical race approach. While the first two are widely accepted, neither approach identifies black Americans as a racial group, instead defining them as a cultural or ethnic group. Accordingly, neither apprehends the full impact of racial inequality in limiting black Americans’ entrepreneurial opportunities. Following a discussion of race-based obstacles to entrepreneurship, the paper concludes that the critical race view provides the most convincing explanation for black Americans’ limited entrepreneurial achievements.     

Selective placement of electron spin resonance spin labels: new structural methods for peptides and proteins.

Electron spin resonance (ESR) is more powerful than ever as a technique for solving biochemical and biophysical problems. Part of the great utility of ESR arises from the use of modern biochemical methods to place spin labels at important positions along the primary sequence of a peptide or protein.     

强化五种意识 提升微生物学实验教学效果

微生物学实验是高校生物技术等专业实践教学的必需环节。提出了实验教学过程中注意强化学生的主动参与意识、无菌操作意识、独立发现问题和解决问题的意识、创新意识以及绿色环保意识。文章对上述问题进行了观察、思考,商讨了解决方法和强化措施。     

Two-Bubble Acoustic Tweezing Cytometry for Biomechanical Probing and Stimulation of Cells

The study of mechanotransduction relies on tools that are capable of applying mechanical forces to elicit and assess cellular responses. Here we report a new (to our knowledge) technique, called two-bubble acoustic tweezing cytometry (TB-ATC), for generating spatiotemporally controlled subcellular mechanical forces on live cells by acoustic actuation of paired microbubbles targeted to the cell adhesion receptor integrin. By measuring the ultrasound-induced activities of cell-bound microbubbles and the actin cytoskeleton contractile force responses, we determine that TB-ATC elicits mechanoresponsive cellular changes via cyclic, paired displacements of integrin-bound microbubbles driven by the attractive secondary acoustic radiation force (sARF) between the bubbles in an ultrasound field. We demonstrate the feasibility of dual-mode TB-ATC for both subcellular probing and mechanical stimulation. By exploiting the robust and unique interaction of ultrasound with microbubbles, TB-ATC provides distinct advantages for experimentation and quantification of applied forces and cellular responses for biomechanical probing and stimulation of cells.