绵枣（Scilla sinensis Merr.）多倍体复合体（广义百合科）的物种生物学研究

本文采用物种生物学的方法分析了绵枣[Scilla sinensis (Lour.) Merr.]多倍体复合体细胞地理、形态、生态适应和发育节律的变异。此外，还对AA细胞型居群进行了等位酶分析和杂交实验。结果如下： 1. 细胞学检查秀自中国境内45个居群，检出AA、AB、BB、AAA、BBB和AABB 6个细胞型。多数居群由1种细胞型组成。AA几乎占据着该复合体在中国的整个分布区。BB仅局限于华中和华东地区。AABB分布于华中和华东地区的北侧、东北地区的东南部及台湾岛。45个居的细胞型组成以细胞地理分布图表示。总结前人与我们的工作，该复合体中已发现12个整倍体细胞型（AA、AB、BB、AAA、ABB、BBB、AAAA、AABB、ABBB、BBBB、AABBB和AAABBB）和各种基于多倍体的非整倍体。其基本细胞型为AA、BB和AABB。AA分布于除日本和大陆上BB分布区中心外该复合体的整个分布区。BB分布中国华东和华中地区、朝鲜的济州岛和日本。AABB分布日本、朝鲜和中国东北地区的东南部及华中、华东地区的东侧。另外，BB居群染色体数量最多，AABB次之，而AA最低。 2. 野外调查和栽培实验表明AA细胞型在中国东部和西部地区间存在形态和生态分化，东部居群形态变异较小，其共同特征是纺锤形鳞茎，红褐色;根茎短柱状;叶多灰绿色，蜡质明显，斜升;花葶较强壮而直立;花紫红色;子房每室1胚珠。西部为AA细胞型的现代变异中心，居群间形态变异大，区别于东部居群的特点是鳞茎纺锤形或近球形，根茎短柱状或盘状，叶鲜绿色，蜡质不明显，平卧地面;花葶1－4枝，直立，多花葶时斜升;花白色或淡红色，子房每室胚珠1 ～ 2枚。AA和BB细胞型是向着适于不同地理区的环境发展，因而具有不同的形态和生物学特性的两个类型。BB鳞茎近球形，黄褐色，根茎不明显，为盘状;叶墨绿色，柔软而平卧地面，是适于阴湿的林下环境的结果。春季萌发较早，约在3月初，其夏季休眠特性刚好可渡过华中地区东部夏季的高温多雨，待秋季温度下降时开花结实。而AA划适应了光照较强而干旱的山坡草地灌丛的类型。其发育节律变异较大，但萌动较BB晚，无夏季休眠。AABB细胞型的形态介于两祖先二倍体之间，没有形成独特的生态适应和发育节律。 3. 对AA细胞型的等位酶分析表明，该种的居群表现出较高的遗传变异（A = 2.0, P = 58.6%, H_o = 0.172 和 H_e = 0.185）。居群间存在较明显的分化(F_(ST) = 0.314)。东西两地区间也存在遗传分化。 4. AA居群间多数组合的F_1都低于对照的花粉育性和结实率。尤其是东部和西部居群间组合的F_1花粉育性和结实率极低，几近不育。如果仅仅考虑该复合体的形态变异，它只能作为一个形态复杂多变的种，Scilla sinensis (Lour) Merr.。可是如此处理就掩盖了其细胞型间清晰的进化关系。为弥补这一缺陷，当研究细胞型间的进化关系时，可采用生物学和概念。AA细胞型为S. sinensis (Lour.) Merr.， 可分两亚种：subsp. sinensis 和 subsp. alboviridis (Hand.-Mazz.) K. Y. Ding。BB细胞型为S. thunbergii Miyabe et Kudo。而ABB及含有A和B染色体组的多倍体作为杂交种S. x sino-japonica K.Y.Ding。两个二倍体种形态界限很清楚，但AABB的存在湮灭了两者的间断。

Music, rhythm, rise time perception and developmental dyslexia: Perception of musical meter predicts reading and phonology

Introduction: Rhythm organises musical events into patterns and forms, and rhythm perception in music is usually studied by using metrical tasks. Metrical structure also plays an organisational function in the phonology of language, via speech prosody, and there is evidence for rhythmic perceptual difficulties in developmental dyslexia. Here we investigate the hypothesis that the accurate perception of musical metrical structure is related to basic auditory perception of rise time, and also to phonological and literacy development in children. Methods: A battery of behavioural tasks was devised to explore relations between musical metrical perception, auditory perception of amplitude envelope structure, phonological awareness (PA) and reading in a sample of 64 typically-developing children and children with developmental dyslexia. Results: We show that individual differences in the perception of amplitude envelope rise time are linked to musical metrical sensitivity, and that musical metrical sensitivity predicts PA and reading development, accounting for over 60% of variance in reading along with age and I.Q. Even the simplest metrical task, based on a duple metrical structure, was performed significantly more poorly by the children with dyslexia. Conclusions: The accurate perception of metrical structure may be critical for phonological development and consequently for the development of literacy. Difficulties in metrical processing are associated with basic auditory rise time processing difficulties, suggesting a primary sensory impairment in developmental dyslexia in tracking the lower-frequency modulations in the speech envelope. © 2010 Elsevier.

Language-universal Sensory Deficits in Developmental Dyslexia: English, Spanish, and Chinese

Studies in sensory neuroscience reveal the critical importance of accurate sensory perception for cognitive development. There is considerable debate concerning the possible sensory correlates of phonological processing, the primary cognitive risk factor for developmental dyslexia. Across languages, children with dyslexia have a specific difficulty with the neural representation of the phonological structure of speech. The identification of a robust sensory marker of phonological difficulties would enable early identification of risk for developmental dyslexia and early targeted intervention. Here, we explore whether phonological processing difficulties are associated with difficulties in processing acoustic cues to speech rhythm. Speech rhythm is used across languages by infants to segment the speech stream into words and syllables. Early difficulties in perceiving auditory sensory cues to speech rhythm and prosody could lead developmentally to impairments in phonology. We compared matched samples of children with and without dyslexia, learning three very different spoken and written languages, English, Spanish, and Chinese. The key sensory cue measured was rate of onset of the amplitude envelope (rise time), known to be critical for the rhythmic timing of speech. Despite phonological and orthographic differences, for each language, rise time sensitivity was a significant predictor of phonological awareness, and rise time was the only consistent predictor of reading acquisition. The data support a language-universal theory of the neural basis of developmental dyslexia on the basis of rhythmic perception and syllable segmentation. They also suggest that novel remediation strategies on the basis of rhythm and music may offer benefits for phonological and linguistic development.

Developmental changes in sleep biology and potential effects on adolescent behavior and caffeine use

Adolescent development includes changes in the biological regulatory processes for the timing of sleep. Circadian rhythm changes and changes to the sleep-pressure system (sleep homeostasis) during adolescence both favor later timing of sleep. These changes, combined with prevailing social pressures, are responsible for most teens sleeping too late and too little; those who sleep least report consuming more caffeine. Although direct research findings are scarce, the likelihood of use and abuse of caffeine-laden products grows across the adolescent years due, in part, to excessive sleepiness

The insect neuropeptide prothoracicotropic hormone is released with a daily rhythm: re-evaluation of its role in development.

Prothoracicotropic hormone (PTTH) is the central cerebral neurohormone in insect development. Its release has been believed for decades to be confined to one (or two) critical moments early in each developmental stage at which time it triggers prolonged activation of the prothoracic glands to synthesize and release the steroid molting hormones (ecdysteroids), which elicit developmental responses in target tissues. We used an in vitro assay for PTTH released from excised brains of the bug Rhodnius prolixus and report that release of PTTH does occur at the expected time on day 6, but that this release is merely the first in a daily rhythm of release that continues throughout most of the 21 days of larval-adult development. This finding, together with reports of circadian control of ecdysteroid synthesis and titer throughout this time, raises significant challenges to several features of the current understanding of the hormonal control of insect development. New questions are raised concerning the function(s) of PTTH, its relationship with the prothoracic glands, and the significance of circadian rhythmicity throughout this endocrine axis. The significance of the reported observations derives from the set of entirely new questions they raise concerning the regulation of insect development.

Identifying developmental problems in young children

Although some developmental disabilities may be identified soon after birth (e.g. Down Syndrome) many problems do not become apparent until much later. The first indication of a significant disorder may be the infant's failure to achieve early developmental milestones at the expected ages, but the variability and subtlety of symtoms in many developmental disorders often makes them difficult to recognise. Clearly itis desirable to identify developmental problems as early as possible to ensure the provision of appropriate support and intervention services and to lessen the impact on subsequent development.

Rare chromosome disorders and their developmental consequences

Professionals working in disability services often encounter clients who have chromosome disorders such as Williams, Angelman or Down syndromes. As chromosome testing becomes increasingly sophisticated, however, more people are being diagnosed with very rare chromosome disorders that are identified not by a syndrome name, but rather by a description of the number, size and shape of their chromosomes (called the karyotype) or by a report of chromosome losses and gains detected through an advanced process known as microarray-based comparative genomic hybridisation (array CGH). For practitioners who work with individuals with rare chromosome disorders and their families, a basic level of knowledge about the evolving field of genetics, as well as specific knowledge about chromosome abnormalities, is essential since they must be able to demonstrate their knowledge and skills to clients (Simic & Turk, 2004). In addition, knowledge about the developmental consequences of various rare chromosome disorders is important for guiding prognoses, expectations, decisions and interventions. The current article provides information that aims to help practitioners work more effectively with this population. It begins by presenting essential information about chromosomes and their numerical and structural abnormalities and then considers the developmental consequences of rare chromosome disorders through a critical review of relevant literature.

Dancing with nature : rhythm and harmony in extreme sport participation

Research on extreme sports has downplayed the importance of the athletes' connection to the natural world. This neglect stems, in part, from the assumption that these activities derive their meaning primarily from risk. The authors' long-term research reveals that the interplay between adventure athletes and the natural world is, in fact, crucial for many participants. This study used hermeneutic and phenomenological analysis of first-hand accounts of these sports and interviews with 15 veteran participants. These included BASE jumpers, big-wave surfers, extreme skiers, waterfall kayakers, extreme mountaineers and solo rope-free climbers. Participants spoke extensively about developing a deep relationship with the natural world akin to an intimate 'dance' between actively engaged partners. Our experience-based analysis has found that extreme sports aficionados do not simply view the natural world as a commodity, a stage for risk taking, or vehicle for self-gratification. On the contrary, for veteran adventure athletes the natural world acts as a facilitator to a deeper, more positive understanding of self and its place in the environment. For some, nature was described as omnipresent and ubiquitous, and a source of innate power and personal meaning. The authors explore how these findings may augment the delivery of more 'ecocentric' programmes in the outdoor adventure field.

Effect of amblyopia on the developmental eye movement test in children

Purpose. To investigate the functional impact of amblyopia in children, the performance of amblyopic and age-matched control children on a clinical test of eye movements was compared. The influence of visual factors on test outcome measures was explored. Methods. Eye movements were assessed with the Developmental Eye Movement (DEM) test, in a group of children with amblyopia (n = 39; age, 9.1 ± 0.9 years) of different causes (infantile esotropia, n = 7; acquired strabismus, n = 10; anisometropia, n = 8; mixed, n = 8; deprivation, n = 6) and in an age-matched control group (n = 42; age, 9.3 ± 0.4 years). LogMAR visual acuity (VA), stereoacuity, and refractive error were also recorded in both groups. Results. No significant difference was found between the amblyopic and age-matched control group for any of the outcome measures of the DEM (vertical time, horizontal time, number of errors and ratio(horizontal time/vertical time)). The DEM measures were not significantly related to VA in either eye, level of binocular function (stereoacuity), history of strabismus, or refractive error. Conclusions. The performance of amblyopic children on the DEM, a commonly used clinical measure of eye movements, has not previously been reported. Under habitual binocular viewing conditions, amblyopia has no effect on DEM outcome scores despite significant impairment of binocular vision and decreased VA in both the better and worse eye.

Radio and affective rhythm in the everyday

This article explores the role of radio sound in establishing what I term ‘affective rhythms’ in everyday life. Through exploring the affective qualities of radio sound and its capacity for mood generation in the home, this article explores personal affective states and personal organisation. The term affective rhythm relates both to mood, and to routine. It is the combination of both that allows the possibility of thinking about sound and affect, and how they relate to, and integrate with, routine everyday life. The notion of ‘affective rhythm’ forces us to consider the idea of mood in the light of the routine nature of everyday domestic life.