It is known that every non-universal self-full degree in the structure of the degrees of computably enumerable equivalence relations (ceers) under computable reducibility has exactly one strong minimal cover. This leaves little room for embedding wide partial orders as initial segments using self-full degrees. We show that considerably more can be done by staying entirely inside the collection of non-self-full degrees. We show that the poset can be embedded as an initial segment of the degrees of ceers with infinitely many (...) classes. A further refinement of the proof shows that one can also embed the free distributive lattice generated by the lower semilattice as an initial segment of the degrees of ceers with infinitely many classes. (shrink)

The relatively simple central nervous system (CNS) of the Drosophila embryo provides a useful model system for investigating the mechanisms that generate and pattern complex nervous systems. Central to the generation of different types of neurons by precursor neuroblasts is the initial specification of neuroblast identity and the Drosophila segment polarity genes, genes that specify regions within a segment or repeating unit of the Drosophila embryo, have emerged recently as significant players in this process. During neurogenesis the segment polarity genes (...) are expressed in the neuroectodermal cells from which neuroblasts delaminate and they continue to be expressed in neuroblasts and their progeny. Loss-of-function mutations in these genes lead to a failure in the formation of neuroblasts and/or specification of neuroblast identity. Results from several recent studies suggest that regulatory interactions between segment polarity genes during neurogenesis lead to an increase in the number of neuroblasts and specification of different identities to neuroblasts within a population of cells. BioEssays 21:472–485, 1999. © 1999 John Wiley & Sons, Inc. (shrink)

Segmentalized consciousness in schizophrenia reflects a loss of the normal Gestalt organization and contextualization of perception. Grays model explains such segmentalization in terms of septohippocampal dysfunction, which is consistent with known neuropsychological impairment in schizophrenia. However, other considerations suggest that everyday perception and its failure in schizophrenia also involve prefrontal executive mechanisms, which are only minimally elaborated by Gray.

A special kind of maximum cuts in sequent derivations, actual maximum cuts, is defined. It is shown that (1) each actual maximum cut of a sequent derivation makes maximum segments in its natural deduction image, and (2) each maximum segment of a natural deduction derivation makes an actual maximum cut in its sequent image.

This paper reconsiders the diphone-based word segmentation model of Cairns, Shillcock, Chater, and Levy (1997) and Hockema (2006), previously thought to be unlearnable. A statistically principled learning model is developed using Bayes’ theorem and reasonable assumptions about infants’ implicit knowledge. The ability to recover phrase-medial word boundaries is tested using phonetic corpora derived from spontaneous interactions with children and adults. The (unsupervised and semi-supervised) learning models are shown to exhibit several crucial properties. First, only a small amount of language (...) exposure is required to achieve the model’s ceiling performance, equivalent to between 1 day and 1 month of caregiver input. Second, the models are robust to variation, both in the free parameter and the input representation. Finally, both the learning and baseline models exhibit undersegmentation, argued to have significant ramifications for speech processing as a whole. (shrink)

Using properties of${\cal K}$-pairs of sets, we show that every nonzero enumeration degreeabounds a nontrivial initial segment of enumeration degrees whose nonzero elements have all the same jump asa. Some consequences of this fact are derived, that hold in the local structure of the enumeration degrees, including: There is an initial segment of enumeration degrees, whose nonzero elements are all high; there is a nonsplitting high enumeration degree; every noncappable enumeration degree is high; every nonzero low enumeration degree can be (...) capped by degrees of any possible local jump ; every enumeration degree that bounds a nonzero element of strictly smaller jump, is bounding; every low enumeration degree below a non low enumeration degreeacan be capped belowa. (shrink)

When infants and toddlers are confronted with sequences of sounds, they are required to segment the sounds into meaningful units to achieve sufficient understanding. Rhythm has been regarded as a crucial cue for segmentation of speech sounds. Although previous intermodal methods indicated that infants and toddlers could detect differences in speech sounds based on stress-timed and syllable-timed units, these methods could not clearly indicate how infants and toddlers perform sound segmentation. Thus, the present study examined whether Japanese infants (...) and toddlers could segment word speech sounds comprising basic morae, on the basis of concurrent basic mora units within syllable units, using the new intermodal matching procedure. The results indicated that, regardless of their ages and linguistic abilities, Japanese infants and toddlers aged 6–25 months tended to segment Japanese words comprising basic morae sounds on the basis of concurrent basic mora units within syllable units. This implies that infants' and toddlers' use of syllable units for segmentation of speech sounds at an early age could be evident among many infants and toddlers learning various languages. Although this finding should be interpreted carefully, the present study demonstrated the utility of the new intermodal matching procedure for examining segmentation of speech sounds and word sounds by infants and toddlers, on the basis of specific rhythm units. (shrink)

We discuss here a series of testable hypotheses concerning the role of chromosome folding into topologically associating domains (TADs). Several lines of evidence suggest that segmental packaging of chromosomal neighborhoods may underlie features of chromatin that span large domains, such as heterochromatin blocks, association with the nuclear lamina and replication timing. By defining which DNA elements preferentially contact each other, the segmentation of chromosomes into TADs may also underlie many properties of long‐range transcriptional regulation. Several observations suggest that TADs (...) can indeed provide a structural basis to regulatory landscapes, by controlling enhancer sharing and allocation. We also discuss how TADs may shape the evolution of chromosomes, by causing maintenance of synteny over large chromosomal segments. Finally we suggest a series of experiments to challenge these ideas and provide concrete examples illustrating how they could be practically applied. (shrink)

Cet article se propose d’appréhender le segment du point de vue de la production, en analysant les séquences identifiées lors du processus d’écriture, c’est-à-dire les unités langagières produites de manière spontanée et ininterrompue (entre deux pauses). Ces unités, que nous appelons jets textuels, ont été enregistrées grâce à l’outil de suivi de rédaction Inputlog. Nous avons tenté de caractériser les jets textuels en les mettant en regard avec divers types d’unités segmentales de langage, qu’elles soient issues de la segmentation (...) des textes finalisés, ou reconnues comme des segments préfabriqués propres à un système lexical ou syntaxique, c’est-à-dire des figements au sens large du terme. Nous nous sommes plus particulièrement penchés sur un parcours de segmentation parallèle, en production (jets textuels) et en réception (segments répétés), pour interroger quelques concepts théoriques et méthodologiques qui sous-tendent les démarches de segmentation : pré-construit, automatisme, mémorisation, figement, enracinement cognitif, fréquence, répétition. (shrink)

Dans cet article, nous appuyant sur un corpus de 3 444 075 tweets correspondant à 44 107 210 tokens (mots, signes de ponctuation, émojis, émoticônes, etc.) recueillis en décembre 2016, nous nous intéressons aux procédés de segmentation à l’œuvre dans les tweets. Après avoir évoqué certaines caractéristiques de ces écrits particuliers, nous rappelons les procédés généraux de segmentation à l’écrit : les signes de ponctuation et les connecteurs. Nous nous penchons ensuite sur la segmentation opérée dans les (...) tweets par ces deux procédés généraux. Enfin, nous montrons que les émoticônes et les émojis constituent des procédés spécifiques permettant de diversifier les stratégies de segmentation des utilisateurs de tweets (et d’autres écrits numériques, tels les SMS et les courriels). (shrink)

This study analyzes the most important predictors of acceptance of social network sites in a sample of Chilean elder people. We employ a novelty procedure to explore this phenomenon. This procedure performs apriori segmentation based on gender and generation. It then applies the deep learning technique to identify the predictors by segments. The predictor variables were taken from the literature on the use of social network sites, and an empirical study was carried out by quota sampling with a sample (...) size of 395 older people. The results show different predictors of social network sites considering all the samples, baby boomer males and females, silent males and females. The high heterogeneity among older people is confirmed; this means that dealing with older adults as a uniform set of users of social network sites is a mistake. This study demonstrates that the four segments behave differently, and many diverse variables influence the acceptance of social network sites. (shrink)

In heterogeneous markets, one of the many consumer groups is that of green product buyers. With rising ethical values, the green market is assuming its place in a general growth trend. Given this, it is important to determine the profile of green product buyers. This study aims to find out whether there are sub-markets for green product buyers, based on their personal values and consumption values, and to determine a detailed profile for these buyers. Both personal values and consumption values (...) are basic factors guiding consumer behaviour and affecting consumption preferences. The data was collected, through surveys in Turkey, from green consumers who were members of the TEMA (the Turkish Foundation for Combating Soil Erosion, for Reforestation and the Protection of Natural Habitats) council. The result of our clustering analysis indicates that green product buyers could be segmented into sub-groups according to their personal values and consumption values. (shrink)

River segmentation of remote sensing images is of important research significance and application value for environmental monitoring, disaster warning, and agricultural planning in an area. In this study, we propose a river segmentation model in remote sensing images based on composite attention network to solve the problems of abundant river details in images and the interference of non-river information including bridges, shadows, and roads. To improve the segmentation efficiency, a composite attention mechanism is firstly introduced in the (...) central region of the network to obtain the global feature dependence of river information. Next, in this study, we dynamically combine binary cross-entropy loss that is designed for pixel-wise segmentation and the Dice coefficient loss that measures the similarity of two segmentation objects into a weighted one to optimize the training process of the proposed segmentation network. The experimental results show that compared with other semantic segmentation networks, the evaluation indexes of the proposed method are higher than those of others, and the river segmentation effect of CoANet model is significantly improved. This method can segment rivers in remote sensing images more accurately and coherently, which can meet the needs of subsequent research. (shrink)

The formation of the segmentation pattern in Drosophila embryos provides an excellent model for investigating the process of pattern formation in multicellular organisms. Several genes required in an embryo for normal segmentation have been analyzed by classical and molecular genetic and morphological techniques. A detailed consideration of these results suggests that these segmentation genes are combinatorially involved in translating the positional identities of individual cells at an early stage in Drosophila development.

. This paper presents a new approach to segment low quality fingerprint images which are collected by low quality fingerprint readers. Images collected using such readers are easy to collect but difficult to segment. The proposed approach is based on combining global and local processing to achieve segmentation of fingerprint images. On the global level, the fingerprint is located and extracted from the rest of the image by using a global thresholding followed by dilation and edge detection of the (...) largest object in the image. On the local level, fingerprint's foreground and its border image are treated using different fuzzy rules. These rules are based on the mean and variance of the block under consideration. The approach is implemented in three stages: pre-processing, segmentation, and post-processing. Segmentation of 100 images was performed and compared with manual examinations by human experts. The experiments showed that 96% of images under test are correctly segmented. The results from the quality of segmentation test revealed that the average error in block segmentation was 2.84% and the false positive and false negatives were approximately 1.4%. This indicates the high robustness of the proposed approach. (shrink)

In Segmented Worlds and Self, Yi-Fu Tuan is sensitive to the fact that “the isolated, critical and self-conscious individual is a cultural artifact” whose development “is closely tied to the evolution of aworld that is progressively more complex, specialized, and segmented.” (p. 139) He argues that in the West this process of segmentation began at the end of the Middle Ages when communal forms of life started to disintegrate and gave way to more individualistic modes of experience and perception. (...) Tuan explores certain manifestations of this process, particularly how the increasing preoccupation with individuality, privacy, and interiority is mirrored in the transformation of eating habits, living arrangements, and the nature of the theatre. (shrink)

Despite decades of research, morphogenesis along the various body axes remains one of the major mysteries in developmental biology. A milestone in the field was the realisation that a set of closely related regulators, called Hox genes, specifies the identity of body segments along the anterior–posterior (AP) axis in most animals. Hox genes have been highly conserved throughout metazoan evolution and code for homeodomain‐containing transcription factors. Thus, they exert their function mainly through activation or repression of downstream genes. However, while (...) much is known about Hox gene structure and molecular function, only a few target genes have been identified and studied in detail. Our knowledge of Hox downstream genes is therefore far from complete and consequently Hox‐controlled morphogenesis is still poorly understood. Genome‐wide approaches have facilitated the identification of large numbers of Hox downstream genes both in Drosophila and vertebrates, and represent a crucial step towards a comprehensive understanding of how Hox proteins drive morphological diversification. In this review, we focus on the role of Hox genes in shaping segmental morphologies along the AP axis in Drosophila, discuss some of the conclusions drawn from analyses of large target gene sets and highlight methods that could be used to gain a more thorough understanding of Hox molecular function. In addition, the mechanisms of Hox target gene regulation are considered with special emphasis on recent findings and their implications for Hox protein specificity in the context of the whole organism. BioEssays 30:965–979, 2008. © 2008 Wiley Periodicals, Inc. (shrink)

chical reinforcement learning that does not rely on a pri ori hierarchical structures Thus the approach deals with a more di cult problem compared with existing work It in volves learning to segment sequences to create hierarchical structures based on reinforcement received during task ex ecution with di erent levels of control communicating with each other through sharing reinforcement estimates obtained by each others The algorithm segments sequences to re duce non Markovian temporal dependencies to facilitate the learning of the (...) overall task Initial experiments demon strated the basic promise of the approach.. (shrink)

The formation of segments in the Drosophila early embryo is understood in greater detail than any other complex developmental process. Now, by studying other types of insect embryo, we can hope to deduce something of the ancestral mechanism of segmentation and the ways in which it has been modified in evolution. The parasitic wasp, Copidosoma floridanum, is spectacularly atypical of insects in that the small egg cell divides extensively, with no initial syncytial phase, and forms eventually some 2000 embryos(1). (...) This process raises intriguing questions about the control of embryonic polarity and segmentation. (shrink)

Studies on Neurospora chromosome segment duplications (Dps) performed since the publication of Perkins's comprehensive review in 1997 form the focus of this article. We present a brief summary of Perkins's seminal work on chromosome rearrangements, specifically, the identification of insertional and quasiterminal translocations that can segregate Dp progeny when crossed with normal sequence strains (i.e., T × N). We describe the genome defense process called meiotic silencing by unpaired DNA that renders Dp‐heterozygous crosses (i.e., Dp × N) barren, which provides (...) a basis for identifying Dps, and discuss whether other processes also might contribute to the barren phenotype of Dp × N and Dp × Dp crosses. We then turn to studies suggesting that large Dps (i.e., >300 kbp) can allow smaller gene‐sized duplications to escape another genome defense process called repeat‐induced point mutation (RIP), possibly by titration of the RIP machinery. Finally, we assess whether in natural populations dominant RIP suppressor Dps provide an “RIP‐free” niche for evolution of new genes following the duplication of existing genes. (shrink)

Cette livraison de Corpus propose de s’intéresser aux faits phraséologiques, c’est-à-dire à cet ensemble de « prêts-à-dire », de « déjà-là », de formules « clef-en-main » aux fonctions communicationnelles variées : zones de confort pour les uns, les faits phraséologiques peuvent faciliter la prise de parole ou les tâches rédactionnelles (Née, Sitri, Veniard 2014 ; Cislaru, Sitri, Pugnière-Saavedra 2013), contribuer à marquer une identité sociale ou professionnelle (Römer 2010 ; Née, Sitri, Ve...

According to mainstream linguistic phonetics, speech can be modeled as a string of discrete sound segments or “phones” drawn from a universal phonetic inventory. Recent work has argued that a mature phonetics should refrain from theorizing about speech and speech processing using sound segments, and that the phone concept should be eliminated from linguistic theory. The paper lays out the tenets of the phone methodology and evaluates its prospects in light of the eliminativist arguments. I claim that the eliminativist arguments (...) fail to show that the phone concept should be eliminated from linguistic theory. (shrink)

A variety of leech homeobox genes have been identified by homology with genes that are known to bring about the regionalization and segmentation of the anteroposterior body axis in other organisms. Embryonic expression patterns suggest a number of interphyletic similarities in the way that these genes are utilized. However, several interesting differences have also been observed. In particular, transplantation experiments in the leech embryo have shown that axially aligned patterns of homeobox gene expression are not specified by a global (...) pattern of positional cues. Rather, the leech independently establishes anteroposterior patterns of gene expression in each of five discrete stem cell lineages, and these patterns are brought into their final alignment through a process of morphogenetic assembly. (shrink)

I review how both the parasegmental and segmental frames are used in constructing the body plan of the arthropods. The parasegment is the primary genetic unit, as shown by Hox gene expression, and the parasegmental design is maintained in the nerve cord. It is, however, not maintained in the epidermis, where the cuticle grooves are segmental, and in the musculature, which is segmental in organisation. This frame shift is reflected in the sensory and motor nerve connections between the ganglia and (...) the periphery. I suggest that the need for movement in an organism equipped with a hard exoskeleton was the functional constraint that shaped this apparently complex mode of development. BioEssays 26:1117–1125, 2004. © 2004 Wiley Periodicals, Inc. (shrink)

We show that in the lattice E Π of Π 0 1 classes there are initial segments [ $\emptyset$ , P] = L(P) which are not Boolean algebras, but which have a decidable theory. In fact, we will construct for any finite distributive lattice L which satisfies the dual of the usual reduction property a Π 0 1 class P such that L is isomorphic to the lattice L(P)*, which is L(P), modulo finite differences. For the 2-element lattice, we obtain (...) a minimal class, first constructed by Cenzer, Downey, Jockusch and Shore in 1993. For the simplest new Π 0 1 class P constructed, P has a single, non-computable limit point and L(P)* has three elements, corresponding to $\emptyset$ , P and a minimal class P $_0 \subset$ P. The element corresponding to P 0 has no complement in the lattice. On the other hand, the theory of L(P) is shown to be decidable. A Π 0 1 class P is said to be decidable if it is the set of paths through a computable tree with no dead ends. We show that if P is decidable and has only finitely many limit points, then L(P)* is always a Boolean algebra. We show that if P is a decidable Π 0 1 class and L(P) is not a Boolean algebra, then the theory of L(P)interprets the theory of arithmetic and is therefore undecidable. (shrink)

The proposed work describes an approach for segmentation of activated sludge flocs from the microscopic images for monitoring wastewater treatment. The morphological features of flocs and filaments are related to the state of an activated sludge wastewater treatment plant and must be monitored for proper functioning. Hence, image processing and analysis could be a time-saving monitoring tool. To address this challenge, we propose a novel framework involving a multiphase edge detection algorithm based on information theory. The proposed framework is (...) evaluated and scrutinized critically considering the artifacts found in the photographs tested. To evaluate the segmentations, gold approximation of estimated truth images is created. In addition, the performance was subjectively evaluated for its potential for segmenting activated sludge images. Experimental results show that the proposed framework exhibits the good results and demonstrates its effectiveness. (shrink)

After around four decades of fast growth, the cruise industry has become the most profitable and dynamic segment in the entire global leisure and tourism sector. Behind this growth is a significant shift in the profile of cruise consumers/passengers/tourists, with growth rates twice as fast as those of other types of tourists. China has become a strategic emerging market for the global cruise industry, quickly developing their cruise reception business and holding about 10% of the market share of global cruisers. (...) In this paper, we examine and categorize various travel motivations of Chinese cruise tourists by means of a questionnaire via factor analysis, mean analysis, and K-cluster analysis. The results of the study indicate that Chinese cruise tourists are primarily encouraged to participate in cruise tourism by the motivational dimensions of family leisure/relaxation, natural and cultural exploration, bond/communication, social respect, tourism shopping, and cruise-promotion information sources. The strongest motivations for Chinese cruise tourists were found to be family leisure/relaxation and natural/cultural exploration. We identify four types of cruisers using the K-means cluster method. We find that for all cruiser demographics, leisure/relaxation is the most important motivational factor. Based on these results, we propose some specific solutions for expanding the customer pool in the Chinese cruise market. (shrink)