Descent Process Research Articles

Nonuniformity correction for an infrared focal plane array based on diamond search block matching.

In scene-based nonuniformity correction algorithms, artificial ghosting and image blurring degrade the correction quality severely. In this paper, an improved algorithm based on the diamond search block matching algorithm and the adaptive learning rate is proposed. First, accurate transform pairs between two adjacent frames are estimated by the diamond search block matching algorithm. Then, based on the error between the corresponding transform pairs, the gradient descent algorithm is applied to update correction parameters. During the process of gradient descent, the local standard deviation and a threshold are utilized to control the learning rate to avoid the accumulation of matching error. Finally, the nonuniformity correction would be realized by a linear model with updated correction parameters. The performance of the proposed algorithm is thoroughly studied with four real infrared image sequences. Experimental results indicate that the proposed algorithm can reduce the nonuniformity with less ghosting artifacts in moving areas and can also overcome the problem of image blurring in static areas.

Open-Water Disposal of Barged Sediments

AbstractA new model for assessing the behavior of sediment clouds due to open-water disposal from barges is presented. The model takes into account the realistic physical condition in which the disposed sediments, due to the large and finite amount of sediments typically carried by the barge, will initially descend as a sediment plume (as if from a continuous release) and then transit into a discrete sediment cloud (as if from an instantaneous release) after the barged sediments are fully discharged. These aspects are not represented in existing models so far. The model also includes the geometrical factors of the barge, which can significantly affect the source conditions and thus the subsequent descent process. Two types of predictions are provided by the model: (1) qualitative predictions of the flow regimes of the sediment clouds along the descending path in the water column, and (2) quantitative predictions of the gross characteristics, such as the penetration rate and growth size of the sediment clo...

Monogenean anchor morphometry: systematic value, phylogenetic signal, and evolution.

Background. Anchors are one of the important attachment appendages for monogenean parasites. Common descent and evolutionary processes have left their mark on anchor morphometry, in the form of patterns of shape and size variation useful for systematic and evolutionary studies. When combined with morphological and molecular data, analysis of anchor morphometry can potentially answer a wide range of biological questions.Materials and Methods. We used data from anchor morphometry, body size and morphology of 13 Ligophorus (Monogenea: Ancyrocephalidae) species infecting two marine mugilid (Teleostei: Mugilidae) fish hosts: Moolgarda buchanani (Bleeker) and Liza subviridis (Valenciennes) from Malaysia. Anchor shape and size data (n = 530) were generated using methods of geometric morphometrics. We used 28S rRNA, 18S rRNA, and ITS1 sequence data to infer a maximum likelihood phylogeny. We discriminated species using principal component and cluster analysis of shape data. Adams’s Kmult was used to detect phylogenetic signal in anchor shape. Phylogeny-correlated size and shape changes were investigated using continuous character mapping and directional statistics, respectively. We assessed morphological constraints in anchor morphometry using phylogenetic regression of anchor shape against body size and anchor size. Anchor morphological integration was studied using partial least squares method. The association between copulatory organ morphology and anchor shape and size in phylomorphospace was used to test the Rohde-Hobbs hypothesis. We created monogeneaGM, a new R package that integrates analyses of monogenean anchor geometric morphometric data with morphological and phylogenetic data.Results. We discriminated 12 of the 13 Ligophorus species using anchor shape data. Significant phylogenetic signal was detected in anchor shape. Thus, we discovered new morphological characters based on anchor shaft shape, the length between the inner root point and the outer root point, and the length between the inner root point and the dent point. The species on M. buchanani evolved larger, more robust anchors; those on L. subviridis evolved smaller, more delicate anchors. Anchor shape and size were significantly correlated, suggesting constraints in anchor evolution. Tight integration between the root and the point compartments within anchors confirms the anchor as a single, fully integrated module. The correlation between male copulatory organ morphology and size with anchor shape was consistent with predictions from the Rohde-Hobbs hypothesis.Conclusions. Monogenean anchors are tightly integrated structures, and their shape variation correlates strongly with phylogeny, thus underscoring their value for systematic and evolutionary biology studies. Our MonogeneaGM R package provides tools for researchers to mine biological insights from geometric morphometric data of speciose monogenean genera.

Descent of mesonephric duct to the final position of the vas deferens in human embryo and fetus.

Because the ureter arises from the mesonephric or Wolffian duct (WD), the WD opening should migrate inferiorly along the urogenital sinus or future urethra. However, this process of descent has not been evaluated morphometrically in previous studies and we know little about intermediate morphologies for the descent. In the present work, serial sagittal sections of 15 specimens at gestational age 6–12 weeks and serial horizontal sections of 20 specimens at 6–10 weeks were analyzed. Monitoring of horizontal sections showed that, until 9 weeks, a heart-, lozenge- or oval-shape of the initial urogenital sinus remained in the bladder and urethra. Thus, the future bladder and urethra could not be distinguished by the transverse section or plane. The maximum width of the urogenital sinus or bladder at 6–10 weeks was 0.8 mm, although its supero-inferior length reached 5 mm at 10 weeks. During earlier stages, however, the medial shift of the WD was rather evident. Depending on the extent of upward growth of the bladder smooth muscle, the descent of the vas deferens became evident at 10–12 weeks. Development of the urethral rhabdosphincter likely resulted in the differentiation of urogenital sinus into the urethra and bladder before formation of the bladder neck with 3-layered smooth muscles. Development of the prostate followed these morphological changes, later accelerating the further descent of the WD opening. Because of their close topographical relationships, slight anomalies or accidents of the umbilical cord at 10–12 weeks may have a significant effect on normal anatomy.

Fracture problem for an external circumferential crack in a functionally graded superconducting cylinder subjected to a parallel magnetic field

In this study, the multiple isoparametric finite element method (MIFEM) is used to investigate external circumferential crack problem of a functionally graded superconducting cylinder subjected to electromagnetic forces. The superconducting cylinder is composed by Bi2223/Ag composite with material parameters varying. A crack reference region is defined to reflect the effects of crack on flux and current densities, and the magnetically impermeable crack surface condition and the generalized Irie–Yamafuji critical state model outside the crack region are adopted. The distributions of magnetic flux density in the superconducting cylinder are obtained analytically for both the zero-field cooling (ZFC) and the field cooling (FC) activation processes. Based on the MIFEM, the stress intensity factors (SIFs) at crack fronts in the process of field ascent and/or descent are then numerically calculated. It is interesting to note from numerical results that for the present crack model in the ZFC activation process, the crack is easily propagate and grow with the applied field increases, and that in the field descent process of either the ZFC case or FC case, the crack generally does not propagate. In addition, in the field ascent process of the ZFC case, the SIFs depend on not only the crack depths and model parameters but also the applied field. The present study should be helpful to the design and application of high-temperature superconductors with external edge cracks.

A generalization of carries process and riffle shuffles

As a continuation to our previous work (Nakano and Sadahiro, 2014), we consider a generalization of carries process. Our results are: (i) right eigenvectors of the transition probability matrix, (ii) correlation of carries between different steps, and (iii) generalized riffle shuffle whose corresponding descent process has the same distribution as that of the generalized carries process.

Asymptotic results for random sums of dependent random variables

Our main result is a central limit theorem for random sums of the form ∑i=1NnXi, where {Xi}i≥1 is a stationary m-dependent process and Nn is a random index independent of {Xi}i≥1. This extends the work of Chen and Shao on the i.i.d. case to a dependent setting and provides a variation of a recent result of Shang on m-dependent sequences. Further, a weak law of large numbers is proven for ∑i=1NnXi, and the results are exemplified with applications on moving average and descent processes.

Analyzing Trends in Software Product Lines Evolution Using aCladistics Based Approach

A software product line is a complex system the aim of which is to provide a platform dedicated to large reuse. It necessitates a great investment. Thus, its ability to cope with customers’ ever-changing requirements is among its key success factors. Great effort has been made to deal with the software product line evolution. In our previous works, we carried out a classification of these works to provide an overview of the used techniques. We also identified the following key challenges of software product lines evolution: the ability to predict future changes, the ability to define the impact of a change easily and the improvement in understanding the change. We have already tackled the second and the third challenges. The objective of this paper is to deal with the first challenge. We use the cladistics classification which was used in biology to understand the evolution of organisms sharing the same ancestor and their process of descent at the aim of predicting their future changes. By analogy, we consider a population of applications for media management on mobile devices derived from the same platform and we use cladistics to construct their evolutionary tree. We conducted an analysis to show how to identify the evolution trends of the case study products and to predict future changes.

Membaca Semangat Hermeneutika Hanafi

Alquran cannot be detached from the chain of history accompanying it. Alquran has always been associated with sacred values it contains. That is it’s <em>fitrah</em>. Hasan Hanafi, born in Cairo, develops a unique hermeneutics to view Alquran as revelation. In safeguarding the originality of the Scripture as much as possible, the potential of reason and thought cannot be avoided as well. For the Scripture is an ideal ‘mirror’ of the expressions of the reality in life together with all the social dynamic continuously approaching the believers. Without the involvement of reason and thought the Scripture might not be so much different from an ‘inscription’, which is passive, cold, and barely engendering things characterised as dialogical and productive. Viewed in its process of descent to human beings, the scriptural revelation is not something suddenly flying and drifting without reason. The revelation is closely related with the reality (of the past) tied up together by Allah. Each verse or set of verses in the Scripture has mirrored solution to particular problem in the banality of individual and communal life. The Scripture is not simply a ‘text’, for it is always breathing ‘context’. By having context, the Scripture cannot be uncoupled from the social reality of the believers who put their trust in it. The Scripture is a text merging with context, which in turn illuminates the believers all around the world.<br /><br />

An anatomical study of descent of testes in fetal cadavers of perinatal period

Abstract Background and aims: Undescended testes or Cryptorchidism is a common congenital anomaly of male gonad. In this condition one or both testes fail to descend into the scrotum as the process of descent may get arrested at any point along its normal path. It is a common condition occurring in 1 in 500 individuals. Undescended testis carries a risk of developing seminoma and is prone to injury. Undescended testis also fails to produce mature spermatozoa leading to infertility. Materials and methods: Hundred perinatal human cadavers were collected and meticulously dissected. Results: Undescended testes were found in 30% cases. In 50% cases, left testis descended earlier than the right. Bilateral undescended testes (70%) were more common than unilateral (30%). Unilateral undescended testis was more common on right side (55.5%). Undescended testes were found in the abdomen in 19.61% of cases. In 50.98% of cases, they were located in the ingoina1region and in the remaining 29.41% of cases, they were found in the subinguinal position. Conclusion : The primary management of cryptorchidism is surgery which is called orchipexy and is usually performed in infancy. When the undescended testis is in the inguinal canal, hormone therapy is sometimes attempted and occasionally successful. Therefore through early diagnosis and surgical interventions, the undescended testes can be replaced to the scrotum that will ensure optimal fertility in adulthood and a considerable lessened risk of testicular carcinoma.

Animal weapons: the evolution of battle

Douglas J Emlen’s Animal Weapons is a hard-hitting campaign—a bit of a Blitzkrieg through major themes in evolutionary escalation, peppered with dazzling examples from across the spectrum of animals and their adaptations, from the horns of dung beetles to the guns of battleships. Although the major lessons of offensive and defensive weaponry, escalation, and sexual selection will be quite familiar to any biologist or biology teacher, Emlen is so intimately immersed in those subjects and such a good communicator that he easily weaves them into some clever new syntheses and clear comparative frameworks. Emlen convincingly shows that there is essentially no difference between the weapons of humans and those of all other species. All of the chapters are infused with examples from the animal world and the world of human technology, and a final section focuses on these parallels in the specific cases of human fortresses (of the land, sea, and air varieties) and weapons of mass destruction. Throughout, he shows that if certain conditions apply—if there are scarce and defensible resources and the opportunity for head-to-head combat— there will be escalation toward bigger and more dangerous weaponry. This parallelism holds up even though much of human weaponry evolves through conscious design and by sharing information laterally rather than through the natural process of descent with modification. Although he doesn’t dwell on it extensively, it is rather remarkable that discoveries of modern biology—particularly the more recent understandings of lateral gene transfer in bacteria, viral evolution, and epigenetics—bring the world of biological evolution even closer to the world of human systems evolution. I can’t go further without mentioning the illustrations by David J Tuss. They are dazzling, emotive, and highly informative. Especially when composed around intra- and inter-specific comparisons, they become far more than eye candy: they are real tools to aid Emlen’s various syntheses. An especially great example is a comparative study of the common curling-up defensive postures of species as far afield in time, space, and phylogeny as trilo bites, pill bugs, cuckoo bees, armadillos, and pangolins. Another comparative illustration, of same-age male elk and beetles with wildly different horn sizes, hammers home Emlen’s point that there are many ways to go about using (or not using) weaponry that your species and sex might be predisposed to produce. The overwhelming recurring theme of Animal Weapons is the multidirectional nature of evolution. Almost every example that Emlen discusses—horns on beetles, armor on knights, antlers on deer—gets bigger, smaller, bigger again, and/or altogether forgotten, depending on where and when you start to look. Weapons get larger and more ominous until they become too costly, or the environment changes, or some disruptive agent turns

Computational Method for Extracting and Modeling Periodicities in Time Series

Periodicity is common in natural processes, however, extraction tools are typically difficult and cumbersome to use. Here we report a computational method developed in MATLAB through a function called Periods with the aim to find the main harmonic components of time series data. This function is designed to obtain the period, amplitude and lag phase of the main harmonic components in a time series (Periods and lag phase components can be related to climate, social or economic events). It is based on methods of periodic regression with cyclic descent and includes statistical significance testing. The proposed method is very easy to use. Furthermore, it does not require full understanding of time series theory, nor require many inputs from the user. However, it is sufficiently flexible to undertake more complex tasks such as forecasting. Additionally, based on previous knowledge, specific periods can be included or excluded easily. The output results are organized into two groups. One contains the parameters of the adjusted model and their F statistics. The other consists of the harmonic parameters that best fit the original series according to their importance and the summarized statistics of the comparisons between successive models in the cyclic descent process. Periods is tested with both, simulated and actual sunspot and Multivariate ENSO Index data to show its performance and accuracy.

Cryptorchidism: current concepts

Cryptorchism is a common anomaly of masculine genitalia affecting up to 5 % fullterm and up to 45 % preterm male newborns. The incidence of congenital cryptorchism is 1,1–1,4 % among infants aged 1 year and does not significantly change until adulthood. The process of normal testicular descent is divided into two stages mediated by androgens and other factors with involvment of various molecular mechanisms. Palpation remains the main diagnostic method but development of radiological techniques stimulates the research of optimal strategy of accurate diagnosis and the choice of treatment. The recommended age for surgical treatment has gradually decreased and approaches 6 to 9 months in many centres. Hormonal treatment of cryptorchidism is more controversial, but increasing evidence suggests the necessity of hormonal intervention for the prevention of complications of cryptorchidism such as infertility and testicular cancer.

Reconstructing the landing trajectory of the CE-3 lunar probe by using images from the landing camera

An accurate determination of the landing trajectory of Chang'e-3 (CE-3) is significant for verifying orbital control strategy, optimizing orbital planning, accurately determining the landing site of CE-3 and analyzing the geological background of the landing site. Due to complexities involved in the landing process, there are some differences between the planned trajectory and the actual trajectory of CE-3. The landing camera on CE-3 recorded a sequence of the landing process with a frequency of 10 frames per second. These images recorded by the landing camera and high-resolution images of the lunar surface are utilized to calculate the position of the probe, so as to reconstruct its precise trajectory. This paper proposes using the method of trajectory reconstruction by Single Image Space Resection to make a detailed study of the hovering stage at a height of 100 m above the lunar surface. Analysis of the data shows that the closer CE-3 came to the lunar surface, the higher the spatial resolution of images that were acquired became, and the more accurately the horizontal and vertical position of CE-3 could be determined. The horizontal and vertical accuracies were 7.09 m and 4.27 m respectively during the hovering stage at a height of 100.02 m. The reconstructed trajectory can reflect the change in CE-3's position during the powered descent process. A slight movement in CE-3 during the hovering stage is also clearly demonstrated. These results will provide a basis for analysis of orbit control strategy, and it will be conducive to adjustment and optimization of orbit control strategy in follow-up missions.

A hybrid algorithm for solving inverse problems in elasticity

Abstract The paper offers a new approach to handling difficult parametric inverse problems in elasticity and thermo-elasticity, formulated as global optimization ones. The proposed strategy is composed of two phases. In the first, global phase, the stochastic hp-HGS algorithm recognizes the basins of attraction of various objective minima. In the second phase, the local objective minimizers are closer approached by steepest descent processes executed singly in each basin of attraction. The proposed complex strategy is especially dedicated to ill-posed problems with multimodal objective functionals. The strategy offers comparatively low computational and memory costs resulting from a double-adaptive technique in both forward and inverse problem domains. We provide a result on the Lipschitz continuity of the objective functional composed of the elastic energy and the boundary displacement misfits with respect to the unknown constitutive parameters. It allows common scaling of the accuracy of solving forward and inverse problems, which is the core of the introduced double-adaptive technique. The capability of the proposed method of finding multiple solutions is illustrated by a computational example which consists in restoring all feasible Young modulus distributions minimizing an objective functional in a 3D domain of a photo polymer template obtained during step and flash imprint lithography.

Autonomous hazard avoidance control for Chang’E-3 soft landing

ChangE-3 is the first mission of Chinese soft landing on celestial body outside Earth. ChangE-3 firstly implements the autonomous hazard avoidance of soft landing using the onboard measured image data. For the feature of autonomous hazard avoidance mission, ChangE-3 firstly presents the relay hazard avoidance control method including the large hazard avoidance of gray-scale-safe & attitude maneuver and the fine hazard avoidance of altitude-safe & position-attitude maneuver. The real flight results of ChangE-3 show that in the powered descent process the safe landing site is acquired, the precise hazard avoidance maneuver is achieved perfectly, and the safety of touch point for soft landing is insured. The autonomous hazard avoidance control and onboard flight results for ChangE-3 are described.

The effects of the diurnal atmospheric variability on entry, descent and landing on Mars

Landing on Mars is extremely challenging task due to the fact that the Martian atmosphere is the most hostile environment in the Solar system to perform the entry, descent and landing (EDL) process, because it is thick enough to create substantial heating of the entry vehicle but not thick enough to reduce its velocity to the one necessary for safe landing. Beside this, the atmosphere is very dynamic mainly due to high eccentricity of the Martian orbit, obliquity of the orbital to the equatorial plane and close alignment of the winter solstice and the orbital perihelion. Although seasonal variations of atmospheric parameters are significantly larger than the diurnal, it is very important to analyze diurnal cycles as they can significantly change vertical and horizontal atmospheric profiles in very short time intervals. This can present a serious threat to missions which have very precise timings and specific requirements such as the requirement for the daytime landing to enable ground images acquisition during the descent and landing phase. A 3-degrees-of-freedom trajectory integration routine was combined with the Mars Global Reference Atmospheric Model (Mars-GRAM) to identify the dependence of the EDL profiles on the diurnal cycles of atmospheric parameters throughout the Martian year. The obtained results show that the influence of the diurnal cycles is the largest at the equator and decreases relatively symmetrically towards the poles with a slightly stronger influence in the northern hemisphere. Also, there is a significant influence of the orbital position of Mars on the effect of diurnal atmospheric variations which causes that, around the orbital perihelion and winter solstice, there is some kind of inversion of the dependance of optimal entry timing on latitude of the landing site comparing to the rest of the Martian year.

Cultural transmission and the evolution of human behaviour: a general approach based on the Price equation

Transmitted culture can be viewed as an inheritance system somewhat independent of genes that is subject to processes of descent with modification in its own right. Although many authors have conceptualized cultural change as a Darwinian process, there is no generally agreed formal framework for defining key concepts such as natural selection, fitness, relatedness and altruism for the cultural case. Here, we present and explore such a framework using the Price equation. Assuming an isolated, independently measurable culturally transmitted trait, we show that cultural natural selection maximizes cultural fitness, a distinct quantity from genetic fitness, and also that cultural relatedness and cultural altruism are not reducible to or necessarily related to their genetic counterparts. We show that antagonistic coevolution will occur between genes and culture whenever cultural fitness is not perfectly aligned with genetic fitness, as genetic selection will shape psychological mechanisms to avoid susceptibility to cultural traits that bear a genetic fitness cost. We discuss the difficulties with conceptualizing cultural change using the framework of evolutionary theory, the degree to which cultural evolution is autonomous from genetic evolution, and the extent to which cultural change should be seen as a Darwinian process. We argue that the nonselection components of evolutionary change are much more important for culture than for genes, and that this and other important differences from the genetic case mean that different approaches and emphases are needed for cultural than genetic processes.

Vibrational and electronic relaxation in MEH-PPV using few cycle pulses

• Electronic dephasing time in MEH-PPV is determined as 25 ± 2 fs using a sub 7 fs pulse. • Self-trapping time of a free exciton to form a polaron is measure as 50 ± 23 fs. • Mechanism of real-time dynamic mode-coupling among vibration modes is clarified. • Energy ladder descent process in vibration modes is clarified by a moment method. The electronic population decay time is determined to be about 500 fs in (poly-[2-methoxy-5-(2′-ethyl-hexyloxy)- p -phenylenevinylene] (MEH-PPV) using 5.7 fs pulses. The ultrafast electronic dephasing time and the self-trapping time of free exciton to form an exciton polaron is determined as 25 ± 2 fs and 50 ± 23 fs, respectively. Real-time spectrogram analysis reveals dynamic mode coupling among the high-frequency and low-frequency modes. The energy-ladder descent vibrational process is clarified using the first moment of the difference absorption spectrum. The phase relaxation time is calculated from the widths of the Fourier spectra of several strongly coupled modes.

Germ cell development in the postnatal testis: the key to prevent malignancy in cryptorchidism?

To permit normal postnatal germ cell development, the mammalian testis undergoes a complex, multi-staged process of descent to the scrotum. Failure of any part of this process leads to congenital cryptorchidism, wherein the malpositioned testis finds itself at the wrong temperature after birth, which leads to secondary germ cell loss and later infertility and risk of cancer. Recent studies suggest that neonatal gonocytes transform into the putative spermatogenic stem cells between 3 and 9 months, and this initial postnatal step is deranged in cryptorchid testes. In addition, it is thought the abnormality high temperature may also impair apoptosis of remaining gonocytes, allowing some to persist to become the possible source of carcinoma in situ and malignancy after puberty. The biology of postnatal germ cell development is of intense interest, as it is likely to be the key to the optimal timing for orchidopexy.