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91.
Ruth A. Stockey 《American journal of botany》1975,62(8):856-868
Seeds and embryos contained within the silicified ovuliferous cone Araucaria mirabilis from the Cerro Cuadrado petrified forest are described. One wingless seed, 0.8–1.3 cm in length and 0.2–0.6 cm in width, is embedded in each ovuliferous scale. Seeds show a three-layered integument and a prominent wavy nucellus which is attached basally to the endotesta. The megagametophyte contains cellular inclusions that may represent starch grains. Ovule vascularization is complex and appears most similar to that of Araucaria bidwillii. Embryos 2 mm long and 0.25 mm wide appear to be in a telo-stage period of development. Shoot apex, cotyledons, root meristem, and calyptroperiblem are present in the embryos in which vascular tissues and secretory elements were beginning to differentiate at the time of fossilization. Embryo ontogeny is considered in light of stages encountered in extant gynmosperm taxa. The absence of the microgametophyte phase in the Cerro Cuadrado collection is discussed. 相似文献
92.
Roots are a highly organised plant tissue consisting of different cell types with distinct developmental functions defined by cell identity networks. Roots are the target of some of the most devastating diseases and possess a highly effective immune system. The recognition of microbe‐ or plant‐derived molecules released in response to microbial attack is highly important in the activation of complex immunity gene networks. Development and immunity are intertwined, and immunity activation can result in growth inhibition. In turn, by connecting immunity and cell identity regulators, cell types are able to launch a cell type‐specific immunity based on the developmental function of each cell type. By this strategy, fundamental developmental processes of each cell type contribute their most basic functions to drive cost‐effective but highly diverse and, thus, efficient immune responses. This review highlights the interdependence of root development and immunity and how the developmental age of root cells contributes to positive and negative outcomes of development‐immunity cross‐talk. 相似文献
93.
A note on the effect of gestation housing environment on approach test measures in gilts 总被引:4,自引:0,他引:4
Jeremy N. Marchant-Forde R. Harry Bradshaw Ruth M. Marchant-Forde Donald M. Broom 《Applied animal behaviour science》2003,80(4):287-296
Systems’ welfare evaluation, including behavioural testing, is becoming increasingly popular in farm animal assurance schemes. The aims of this study were to investigate whether fairly short-term exposure to gestation housing systems, which varied in physical, environmental and human-input factors, influenced behavioural and physiological measures during a human approach test—often used to identify problems in human–animal interactions. Twenty-four Large White×Landrace gilts were initially subjected to identical human contact and daily husbandry. Forty-two days after service, the gilts were randomly assigned to either an indoor housing system (n=16) or an outdoor housing system (n=8), which differed physically and in the amount of human contact and daily husbandry. The indoor system used an electronic sow feeder (ESF), was more space-limited and thermally-controlled and had human contact centered on cleaning out. The outdoor system was more extensive, had much greater space accessible, was not thermally-controlled and had human contact that centered around feeding. The human approach test was carried out on all gilts 30–44 days after entry to the gestation system. At testing, each individual was fitted with heart rate monitor and then moved into a test arena. After 2 min an unfamiliar human entered the pen and stood motionless for 3 min against one wall and then approached the gilt and touched her snout. Throughout the experimental period, behaviour and sound within the test arena were recorded continuously. During the 2 min familiarisation period, outdoor gilts had lower heart rates (108.2 bpm versus 123.7 bpm, P<0.05) and tended to perform fewer short vocalisations (0.5 calls per min versus 3.4 calls per min, P<0.1). Outdoor-housed gilts also carried out less locomotor behaviour (2.2 sections crossed versus 4.0 sections crossed, P<0.05) and tended to perform fewer short (1.4 calls per min versus 5.0 calls per min, P<0.1) and long vocalisations (0.2 calls per min versus 1.8 calls per min, P<0.1) over the 3 min test period. Outdoor gilts tended to be slower to approach within 0.5 m of the human (69.9 s versus 19.3 s, P<0.1) but they then took less extra time to make physical contact (3.3 s versus 52.7 s, P<0.1). Mean heart rate was significantly lower in outdoor sows over the whole 3 min period (99.5 bpm versus 115.5 bpm, P<0.05). The results demonstrate that short-term exposure to different housing systems did influence behavioural and physiological measures during a standard human approach test and thus, systems differences should be taken into account before making judgements about the human–animal relationship on any commercial farm, based on results of behavioural tests of this type. 相似文献
94.
Lisa M. Stout Ruth E. Blake James P. Greenwood Anna M. Martini & Eben C. Rose 《FEMS microbiology ecology》2009,70(3):70-80
The volcanic Sulphur Springs, St. Lucia, present an extreme environment due to high temperatures, low pH values, and high concentrations of sulfate and boron. St. Lucia offers some unique geochemical characteristics that may shape the microbial communities within the Sulphur Springs area. We chose six pools representing a range of geochemical characteristics for detailed microbial community analyses. Chemical concentrations varied greatly between sites. Microbial diversity was analyzed using 16S rRNA gene clone library analyses. With the exception of one pool with relatively low concentrations of dissolved ions, microbial diversity was very low, with Aquificales sequences dominating bacterial communities at most pools. The archaeal component of all pools was almost exclusively Acidianus spp. and did not vary between sites with different chemical characteristics. In the pool with the highest boron and sulfate concentrations, only archaeal sequences were detected. Compared with other sulfur springs such as those at Yellowstone, the microbial diversity at St. Lucia is very different, but it is similar to that at the nearby Lesser Antilles island of Montserrat. While high elemental concentrations seem to be related to differences in bacterial diversity here, similarities with other Lesser Antilles sites suggest that there may be a biogeographical component as well. 相似文献
95.
Llorenç Milà i Canals Christian Bauer Jochen Depestele Alain Dubreuil Ruth Freiermuth Knuchel Gérard Gaillard Ottar Michelsen Ruedi Müller-Wenk Bernt Rydgren 《The International Journal of Life Cycle Assessment》2007,12(1):5-15
Background, Aim and Scope
Land use by agriculture, forestry, mining, house-building or industry leads to substantial impacts, particularly on biodiversity
and on soil quality as a supplier of life support functions. Unfortunately there is no widely accepted assessment method so
far for land use impacts. This paper presents an attempt, within the UNEP-SETAC Life Cycle Initiative, to provide a framework
for the Life Cycle Impact Assessment (LCIA) of land use.
Materials and Methods:
This framework builds from previous documents, particularly the SETAC book on LCIA (Lindeijer et al. 2002), developing essential
issues such as the reference for occupation impacts; the impact pathways to be included in the analysis; the units of measure
in the impact mechanism (land use interventions to impacts); the ways to deal with impacts in the future; and bio-geographical
differentiation.
Results:
The paper describes the selected impact pathways, linking the land use elementary flows (occupation; transformation) and parameters
(intensity) registered in the inventory (LCI) to the midpoint impact indicators and to the relevant damage categories (natural
environment and natural resources). An impact occurs when the land properties are modified (transformation) and also when
the current man-made properties are maintained (occupation).
Discussion:
The size of impact is the difference between the effect on land quality from the studied case of land use and a suitable reference
land use on the same area (dynamic reference situation). The impact depends not only on the type of land use (including coverage
and intensity) but is also heavily influenced by the bio-geographical conditions of the area. The time lag between the land
use intervention and the impact may be large; thus land use impacts should be calculated over a reasonable time period after
the actual land use finishes, at least until a new steady state in land quality is reached.
Conclusions:
Guidance is provided on the definition of the dynamic reference situation and on methods and time frame to assess the impacts
occurring after the actual land use. Including the occupation impacts acknowledges that humans are not the sole users of land.
Recommendations and Perspectives:
The main damages affected by land use that should be considered by any method to assess land use impacts in LCIA are: biodiversity
(existence value); biotic production potential (including soil fertility and use value of biodiversity); ecological soil quality
(including life support functions of soil other than biotic production potential). Bio-geographical differentiation is required
for land use impacts, because the same intervention may have different consequences depending on the sensitivity and inherent
land quality of the environment where it occurs. For the moment, an indication of how such task could be done and likely bio-geographical
parameters to be considered are suggested. The recommendation of indicators for the suggested impact categories is a matter
of future research. 相似文献
96.
Evangelia Stergiakouli Romy Gaillard Jeremy M. Tavaré Nina Balthasar Ruth J. Loos Hendrik R. Taal David M. Evans Fernando Rivadeneira Beate St Pourcain André G. Uitterlinden John P. Kemp Albert Hofman Susan M. Ring Tim J. Cole Vincent W.V. Jaddoe George Davey Smith Nicholas J. Timpson 《Obesity (Silver Spring, Md.)》2014,22(10):2252-2259
97.
98.
Two complementary experiments were conducted in a controlled environment to elucidate the interactions between the fungus Sclerotinia trifoliorum Erikss. and red clover (Trifolium pratense L.). In one of these studies, two hardened diploid red clover cultivars (cvs) were inoculated with 20 isolates of S. trifoliorum of various geographic origins. In the other study, 20 red clover cvs, diploid or tetraploid, including late and medium‐late flowering types, were inoculated with two isolates of the fungus. Prior to inoculation, some plants were hardened by subjecting them to a low temperature and light treatment mimicking autumn conditions. Late flowering cvs were found more resistant than medium‐late ones. Isolates collected in the northern region, where late cvs are grown, were significantly more aggressive than isolates from southern locations, where medium‐late cvs are more prevalent. Such an adaptation has not previously been reported for this fungus. This is the first report concerning flowering type and resistance in red clover. Tetraploids were generally not more resistant than diploids. A hardening procedure for red clover plants was found to be a prerequisite for detecting the differences in disease resistance. 相似文献
99.
Ruth Falkenberg Maximilian Fochler Lisa Sigl Hermann Bürstmayr Stephanie Eichorst Sebastian Michel Eva Oburger Christiana Staudinger Barbara Steiner Dagmar Woebken 《EMBO reports》2022,23(7)
Research needs a balance of risk‐taking in “breakthrough projects” and gradual progress. For building a sustainable knowledge base, it is indispensable to provide support for both. Subject Categories: Careers, Economics, Law & Politics, Science Policy & PublishingScience is about venturing into the unknown to find unexpected insights and establish new knowledge. Increasingly, academic institutions and funding agencies such as the European Research Council (ERC) explicitly encourage and support scientists to foster risky and hopefully ground‐breaking research. Such incentives are important and have been greatly appreciated by the scientific community. However, the success of the ERC has had its downsides, as other actors in the funding ecosystem have adopted the ERC’s focus on “breakthrough science” and respective notions of scientific excellence. We argue that these tendencies are concerning since disruptive breakthrough innovation is not the only form of innovation in research. While continuous, gradual innovation is often taken for granted, it could become endangered in a research and funding ecosystem that places ever higher value on breakthrough science. This is problematic since, paradoxically, breakthrough potential in science builds on gradual innovation. If the value of gradual innovation is not better recognized, the potential for breakthrough innovation may well be stifled.
While continuous, gradual innovation is often taken for granted, it could become endangered in a research and funding ecosystem that places ever higher value on breakthrough science.Concerns that the hypercompetitive dynamics of the current scientific system may impede rather than spur innovative research have been voiced for many years (Alberts et al, 2014). As performance indicators continue to play a central role for promotions and grants, researchers are under pressure to publish extensively, quickly, and preferably in high‐ranking journals (Burrows, 2012). These dynamics increase the risk of mental health issues among scientists (Jaremka et al, 2020), dis‐incentivise relevant and important work (Benedictus et al, 2016), decrease the quality of scientific papers (Sarewitz, 2016) and induce conservative and short‐term thinking rather than risk‐taking and original thinking required for scientific innovation (Alberts et al, 2014; Fochler et al, 2016). Against this background, strong incentives for fostering innovative and daring research are indispensable. 相似文献