土圞儿属和旋花豆属的系统学研究

土圞儿属（含8种）和旋花豆属（含2种）隶属于豆科、菜豆族、刺桐亚族。土圞儿属呈东亚-北美间断分布，旋花豆属分布于喜玛拉雅地区。传统上，这两个属被认为系统关系非常近。目前对于土圞儿属中种的划分和分类问题缺乏世界范围内的深入研究，因此该属应予以修订。另外，土圞儿属内种间和土圞儿属与旋花豆属间的系统关系也需要进一步研究。本文对这两个属进行了世界范围内的分类学修订。同时，基于形态学、解剖学、孢粉学特征和分子系统学方面的研究，对土圞儿属内部和这两个属之间的系统发育关系进行了探讨。结果如下： 1. 形态学 在标本室研究和野外考查的基础上，对土圞儿属和旋花豆属植物形态性状的变异式样及其分类学意义进行了分析，发现块茎的形态、小叶的大小和形态、花序的类型和花冠的形态等特征在种内稳定，是比较可靠的分类学性状。通过对花序的研究，认为花序的类型可能反映了土圞儿属内各种之间的演化关系，推测肉色土圞儿可能是土圞儿属中较为进化的种类，而云南土圞儿和纤细土圞儿则可能较为原始。 2. 叶表皮特征 首次在光学显微镜和扫描电子显微镜下，对土圞儿属和旋花豆属全部8种植物的叶表皮进行了观察。发现这两个属叶表皮的性状，特别是表皮细胞的形状、垂周壁的式样和蜡质纹饰的特征，对于理解土圞儿属内和这两个属之间的系统关系有重要意义。叶表皮的特征支持以下结论：纤细土圞儿是一个独立的种，而不是云南土圞儿之下的一个变种;对于土圞儿属进行亚属的划分是不合理的。 3. 孢粉学 在光学显微镜和扫描电子显微镜下，对7种土圞儿属和旋花豆属植物的花粉进行了观察。这两个属的花粉均为三孔沟，三角球形或球形。土圞儿属的花粉可划分为两种类型：肉色土圞儿的花粉外壁为典型的网状纹饰;其他的种花粉外壁较光滑，具颗粒状或短条纹状纹饰。肉色土圞儿花粉外壁纹饰的类型可能反映了其在Apios属中较进化的位置。旋花豆属的花粉特征和肉色土圞儿相似，这也许说明了两者之间的亲缘关系较近。 4. 分子系统学 通过对土圞儿属和旋花豆属6种植物的两个DNA片段ITS和H3D进行简约性分析，构建了这两个属之间的系统关系树。结果如下：土圞儿属和旋花豆属是亲缘关系较近的姐妹群;土圞儿属自身组成一个单系群，是一个自然的类群;北美的土圞儿聚成一支，隐藏在东亚的种里。分子证据和花序类型、花粉形态等重要的形态学证据相吻合。基于上述证据，我们对土圞儿属东亚-北美间断分布的格局及其可能的成因进行了初步探讨。 5. 分类修订 对土圞儿属和旋花豆属进行了分类修订，考证了关于这两个属曾发表过的所有的名称。确认了土圞儿属应包含6种，旋花豆属有2种。排除了5个不包括在土圞儿属内的种名。此外，本文还给出了这两个属各个种的地理分布图、分种检索表、形态描述和插图。

黄杉属的分子系统发育与生物地理学

松科植物的叶绿体和线粒体基因分别为父系和母系遗传，二者的联合分析为系统发育重建，特别是揭示网状进化过程提供了便利条件。此外，松科中的多个属（如黄杉属、铁杉属等）呈洲际间断分布，是研究生物地理学问题的良好试材。 本文选择来自于叶绿体和线粒体基因组的5个DNA片段，通过序列分析对黄杉属的所有8个种进行了系统发育重建;同时结合已有的对黄杉属的各方面研究，讨论了该属典型的东亚-北美间断分布式样的形成过程。主要结果如下： (1) 叶绿体DNA片段trnfM-trnS、rpl20和trnP的序列分析 无论叶绿体基因两两组合分析还是3个叶绿体片段的联合分析均强烈支持东亚的6种黄杉属植物聚为一支（支持率>96%），其中日本黄杉位于最基部，其他分布于中国的5个种聚在一起。 (2) 线粒体基因nad5和cox1的序列分析 线粒体基因序列的进化速率较慢，信息位点相对较少，因此分辨率较低。本文中线粒体DNA序列在黄杉属的东亚物种间几乎没有分辨率，但是仍以>60%的Bootstrap支持率将该属分为东亚与北美两个姐妹支。 (3) 5个DNA片段的联合分析 5个细胞质DNA片段(trnfM-trnS, rpl20, trnP, nad5, cox1)的联合数据矩阵长4351 bp，其中含变异位点129个（3.0%），信息位点109个（2.5%）。利用最大简约法进行的系统发育分析表明：黄杉属分成北美和东亚两支，与地理分布相吻合，并分别得到了66%和100%的支持;中国的5个物种形成一个单系分支，该分支与日本黄杉为姐妹群关系。 根据上述叶绿体和线粒体DNA片段的序列分析结果，并结合前人的研究资料，我们认为黄杉属通过白令陆桥扩散后，在北美和东亚独立进化，但该属的起源地尚需要进一步研究。

Historical knowledge of sharks: ancient science, earliest American encounters, and American science, fisheries, and utilization

In western civilization, the knowledge of the elasmobranch or selachian fishes (sharks and rays) begins with Aristotle (384–322 B.C.). Two of his extant works, the “Historia Animalium” and the “Generation of Animals,” both written about 330 B.C., demonstrate knowledge of elasmobranch fishes acquired by observation. Roman writers of works on natural history, such as Aelian and Pliny, who followed Aristotle, were compilers of available information. Their contribution was that they prevented the Greek knowledge from being lost, but they added few original observations. The fall of Rome, around 476 A.D., brought a period of economic regression and political chaos. These in turn brought intellectual thought to a standstill for nearly one thousand years, the period known as the Dark Ages. It would not be until the middle of the sixteenth century, well into the Renaissance, that knowledge of elasmobranchs would advance again. The works of Belon, Salviani, Rondelet, and Steno mark the beginnings of ichthyology, including the study of sharks and rays. The knowledge of sharks and rays increased slowly during and after the Renaissance, and the introduction of the Linnaean System of Nomenclature in 1735 marks the beginning of modern ichthyology. However, the first major work on sharks would not appear until the early nineteenth century. Knowledge acquired about sea animals usually follows their economic importance and exploitation, and this was also true with sharks. The first to learn about sharks in North America were the native fishermen who learned how, when, and where to catch them for food or for their oils. The early naturalists in America studied the land animals and plants; they had little interest in sharks. When faunistic works on fishes started to appear, naturalists just enumerated the species of sharks that they could discern. Throughout the U.S. colonial period, sharks were seldom utilized for food, although their liver oil or skins were often utilized. Throughout the nineteenth century, the Spiny Dogfish, Squalus acanthias, was the only shark species utilized in a large scale on both coasts. It was fished for its liver oil, which was used as a lubricant, and for lighting and tanning, and for its skin which was used as an abrasive. During the early part of the twentieth century, the Ocean Leather Company was started to process sea animals (primarily sharks) into leather, oil, fertilizer, fins, etc. The Ocean Leather Company enjoyed a monopoly on the shark leather industry for several decades. In 1937, the liver of the Soupfin Shark, Galeorhinus galeus, was found to be a rich source of vitamin A, and because the outbreak of World War II in 1938 interrupted the shipping of vitamin A from European sources, an intensive shark fishery soon developed along the U.S. West Coast. By 1939 the American shark leather fishery had transformed into the shark liver oil fishery of the early 1940’s, encompassing both coasts. By the late 1940’s, these fisheries were depleted because of overfishing and fishing in the nursery areas. Synthetic vitamin A appeared on the market in 1950, causing the fishery to be discontinued. During World War II, shark attacks on the survivors of sunken ships and downed aviators engendered the search for a shark repellent. This led to research aimed at understanding shark behavior and the sensory biology of sharks. From the late 1950’s to the 1980’s, funding from the Office of Naval Research was responsible for most of what was learned about the sensory biology of sharks.

Climatic impacts of the 1991-92 Western winter

EXTRACT (SEE PDF FOR FULL ABSTRACT): The latest in a series of unusual winters affected the western United States during 1991-92. This report is primarily concerned with the 6 to 8 coolest months, with some consideration of the adjacent summer months. ... Much of the winter was characterized by "split flow" west of North America. As it approached the West Coast, the jet stream frequently diverged into a northern branch toward Panhandle Alaska and a second southern branch that dived south along the California coast and then eastward along the US-Mexican border. Repeatedly, storms approaching the West Coast were stretched north-to-south, losing their organization in the process.

Demographic assessment of the blue crab (Callinectes sapidus) in Chesapeake Bay using extractable lipofuscins as age markers

The blue crab (Callinectes sapidus) plays an important economic and ecological role in estuaries and coastal habitats from the Gulf of Mexico to the east coast of North America, but demographic assessments are limited by length-based methods. We applied an alternative aging method using biochemical measures of metabolic byproducts (lipofuscins) sequestered in the neural tissue of eyestalks to examine population age structure. From Chesapeake Bay, subsamples of animals collected from the 1998–99 (n=769) and 1999–2000 (n=367) winter dredge surveys were collected and lipofuscin was measured. Modal analysis of the lipofuscin index provided separation into three modes, whereas carapace-width data collected among the same individuals showed two broad modes. Lipofuscin modal analysis indicated that most adults (carapace width >120 mm) were <2 years old. The results indicate that use of extractable lipofuscin can provide a more accurate and better resolved estimation of demographic structure of blue crab populations in the field than size alone.

Introduction

In 1984, a workshop was held on "climatic variability of the eastern North Pacific and western North America." From it has emerged an annual series of workshops held each spring at the Asilomar Conference Center, Monterey Peninsula, California. These annual gatherings have come to be called PACLIM (Pacific Climate) Workshops, reflecting broad interests in the climatologies associated with the Pacific Ocean. Participants in the six workshops that have convened since 1984 have included atmospheric scientists, hydrologists, geologists, glaciologists, oceanographers, limnologists, and both marine and terrestrial biologists.

Pacific sea surface temperature associations with southwestern United States summer rainfall and atmospheric circulation

Pacific sea surface temperatures (SSTs) are examined for their associations with (1) summer rainfall, and (2) the latitude location of the mid-tropospheric subtropical high pressure ridge (STR) in the southwestern United States during 1945 to 1986. Extreme northward (southward) displacements of STR are associated with wet (dry) summers over Arizona and an enhanced (weakened) gradient of SST off the California and Baja coasts. These tend to follow winters marked by positive (negative) phases of the PNA, Pacific/North America, teleconnection pattern. Recent decadal variations of Arizona summer rainfall (1950s wet; 1970s dry) appear similarly related to southwestern United States synoptic circulation and eastern Pacific SSTs.

Can a climate record be extracted from giant sequoia tree rings?

Extreme low growth events in giant sequoia ring-width index series coincide with severe droughts in the San Joaquin drainage, on whose eastern flank the sequoia groves stand. Comparison with a network of 102 largely moisture-sensitive tree-ring chronologies from western North America suggests that this relationship has been stable for at least 380 years. The twentieth century is not unusual in the frequency of these events. We expect the growth record will soon be replicated for over 2000 years at two locations.

Introduction

In 1984, a workshop was held on "Climatic variability of the eastern North Pacific and western North America". From it has emerged an annual series of workshops held each spring at the Asilomar Conference Center, Monterey Peninsula, California. These annual gatherings have come to be called PACLIM (Pacific Climate) Workshops, reflecting broad interests in the climatologies associated with the Pacific Ocean.

ENSO influences on atmospheric circulation and precipitation in the western United States

EXTRACT (SEE PDF FOR FULL ABSTRACT): The influence of ENSO on atmospheric circulation and precipitation over the western United States is presented from two perspectives. First, ENSO-associated circulation patterns over the North Pacific/North America sector were identified using an REOF (rotated empirical orthogonal function) analysis of the 700-mb height field and compositing these for extreme phases of the Southern Oscillation Index. ... Second, we examine the variability of precipitation during the warm and cool phases of ENSO for different locations in the western United States.

Some effects of Earth's surface on winter jet stream positions in the Northern Hemisphere and rainfall patterns in northern and central California

EXTRACT (SEE PDF FOR FULL ABSTRACT): This report shows that the mean wintertime polar-front jet stream structure consists of three long waves. Prominent ridges in the jet stream flow occur near the longitudes of India, eastern Pacific/west coast of North America, and eastern Atlantic/British Isles; prominent troughs occur near the longitudes of the Middle East, western Pacific, and western Atlantic/east coast of North America. ... One of the climatological ridges occurs along the west coast of North America ... just off the central Oregon coast. The position of the jet stream at this location appears to be the main reason most Pacific storms pass to the north of California. Sustained rainfall in northern and central California occurs only when the storm track is displaced southward of this climatological position.

Interdecadal variability in the spatial structure of wind and SST in the California Current system

The physical environment of eastern boundary current systems is rarely uniform in time. ENSO and other perturbations produce profound anomalies in the atmosphere and ocean on interannual to decadal and century time scales. ... The objective of this paper is to describe the temporal variability in the spatial texture of the California Current system, a major eastern boundary current system off the west coast of North America, to provide a base from which to evaluate the effect of climate change - in the recent past, at present, and for the future.

Interannual variability in the PFEG coastal upwelling indices

Numerous studies examine decadal-scale variability in basin-scale parameters in the Northern Pacific. Characterizing such interannual-to-interdecadal variability is essential to identifying long-term climate changes. The Pacific Fisheries Environmental Group (PFEG) coastal upwelling indices display variability on these time scales and may help explain the mechanisms responsible for such climate variability. ... In this study, examination of 49-year time series of monthly mean upwelling indices at the 15 PFEG-standard positions along the west coast of North America revealed variability on large spatial scales as well as temporal scales.

Interannual to decadal time-scale variations in glacier mass balance [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): The mass balance of glaciers depends on the seasonal variation in precipitation, temperature, and insolation. For glaciers in western North America, these meteorological variables are influenced by the large-scale atmospheric circulation over the northern Pacific Ocean. The purpose of this study is to gain a better understanding of the relationship between mass balance at glaciers in western North America and the large-scale atmospheric effects at interannual and decadal time scales.

Response of Pacific Northwest vegetation to large-scale changes in climate during the last 100,000 years [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Paleoclimatic variations in western North America depend on a hierarchy of temporal and spatial controls that can be examined using a combination of modeling studies and data synthesis. ... The regional vegetation response to large-scale changes in the climate system of the last 21,000 years is used as a conceptual model to help explain earlier vegetation and climate at two localities.