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排序方式: 共有170条查询结果,搜索用时 31 毫秒
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Principal component models for sparse functional data 总被引:5,自引:0,他引:5
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入侵种喜旱莲子草和莲子草的营养生长和光合作用对温度的响应 总被引:2,自引:0,他引:2
比较温度对入侵种喜旱莲子草(Alternantheraphiloxeroides(Mart.)Griseb.)和其本土近缘种莲子草(A.sessilis(L.)DC.)的营养生长、叶片光合作用及叶绿素荧光的影响。实验将生长均衡的这两种植物放在不同温度(10℃、15℃、20℃、25℃、30℃)的光照培养箱中处理28d。结果表明,喜旱莲子草营养生长的速率和对温度的响应明显不同于莲子草:前者主茎生长的有效积温明显低于后者,分别是11.6d℃和27.0d℃;而新叶萌发的有效积温高于后者,分别是12.1d℃和6.7d℃。入侵种主茎和叶的发育起点温度都比本土种低,分别是10.4℃、11.0℃和12.8℃、14.9℃,表明喜旱莲子草的发育对低温反应不及莲子草敏感。对两种植物叶片的光合作用和叶绿素荧光的测定结果还表明:入侵种比本土种有较高的最大净光合速率和光饱和点,尤其在25℃时;10-30℃的温度范围内喜旱莲子草的最大光化学效率Fv/Fm没有显著变化,而莲子草在10℃低温条件下Fv/Fm值显著降低。较快的主茎生长速率、较宽的温度适应范围以及较高的光合能力可能使喜旱莲子草比本地种具有更强的竞争力,从而在其入侵过程中起了重要作用。 相似文献
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玉米叶片生长部位渗透调节和生长的生物物理参数变化 总被引:6,自引:0,他引:6
玉米叶片生长部位随着水分胁迫加剧ψ_w降低、LER减慢。LER从最大到零,快速干旱处理的ψw从-0.55降至-0.85 MPa;缓慢干旱处理ψ_w从-0.88降至-1.13 MPa。在任何一种LER下,缓慢干旱处理的ψ_s比快速干旱处理更低,生长停止时,前者为-1.57 MPa,而后者为-1.30MPa。缓慢干旱叶片尽管在更低ψ_w下,仍能维持一定膨压,保持一定的生长速率。经历长时间水分胁迫会改变细胞延伸生长的生物物理参数,增大临界膨压(0.08~0.09 MPa)。这是水分胁迫植株,在一定ψ_p下生长速率减慢的原因。 相似文献
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Lívia CA Ribeiro Lívia C Massimino Araceli C Durante Aline Tansini Ana C Urbaczek Heloísa S Selistre-de-Araújo Iracilda Z Carlos 《Cell Adhesion & Migration》2014,8(1):60-65
Integrin αvβ3 is most likely the foremost modulator of angiogenesis among all known integrins. Recombinant disintegrin DisBa-01, originally obtained from snake venom glands, binds to αvβ3, thereby significantly inhibiting adhesion and generating in vivo anti-metastatic ability. However, its function in mediator production is not clear. Here, we observed that the mediators VEGF-A, IL-8, and TGF-β are not produced by human umbilical vein endothelial cells (HUVEC cell line) or monocyte/macrophage cells (SC cell line) when cells adhered to vitronectin. However, when exposed to DisBa-01, HUVECs produced higher levels of TGF-β, and SC cells produced higher levels of VEGF-A. Nonetheless, HUVECs also showed an enhancement of apoptosis after losing adherence when exposed to disintegrin, which is a characteristic of anoikis. We propose that disintegrin DisBa-01 could be used to modulate integrin αvβ3 functions. 相似文献
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F. GREGORY BAUMANN HENRY D. ISENBERG JOSEPH GENNARO 《The Journal of eukaryotic microbiology》1978,25(2):253-256
SYNOPSIS Chemical analysis of axenic cultures of Hymenomonas sp. reveals that the degree of coccolith calcification is inversely proportional to the concentration of available nitrogen sources in the medium. This relationship makes possible a useful degree of control over the organism's calcifying activities. In addition, a possible selective advantage of such a relationship in nature is suggested. 相似文献
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NORMAN SARTORIUS WOLFGANG GAEBEL HELEN‐ROSE CLEVELAND HEATHER STUART TSUYOSHI AKIYAMA JULIO ARBOLEDA‐FLÓREZ ANJA E. BAUMANN OYE GUREJE MIGUEL R. JORGE MARIANNE KASTRUP YURIKO SUZUKI ALLAN TASMAN 《World psychiatry》2010,9(3):131-144
In 2009 the WPA President established a Task Force that was to examine
available evidence about the stigmatization of psychiatry and psychiatrists
and to make recommendations about action that national psychiatric societies
and psychiatrists as professionals could do to reduce or prevent the stigmatization
of their discipline as well as to prevent its nefarious consequences. This
paper presents a summary of the Task Force’s findings and recommendations.
The Task Force reviewed the literature concerning the image of psychiatry
and psychiatrists in the media and the opinions about psychiatry and psychiatrists
of the general public, of students of medicine, of health professionals other
than psychiatrists and of persons with mental illness and their families.
It also reviewed the evidence about the interventions that have been undertaken
to combat stigma and consequent discrimination and made a series of recommendations
to the national psychiatric societies and to individual psychiatrists. The
Task Force laid emphasis on the formulation of best practices of psychiatry
and their application in health services and on the revision of curricula
for the training of health personnel. It also recommended that national psychiatric
societies establish links with other professional associations, with organizations
of patients and their relatives and with the media in order to approach the
problems of stigma on a broad front. The Task Force also underlined the role
that psychiatrists can play in the prevention of stigmatization of psychiatry,
stressing the need to develop a respectful relationship with patients, to
strictly observe ethical rules in the practice of psychiatry and to maintain
professional competence. 相似文献
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