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Jafari and Smith hypothesized that time during games may pass slower for the world’s best football player, Lionel Messi, from Argentina. This hypothesis leads to two questions: How can we explain such temporal paradox and how could this explain his dominant performances? Remarkably, the Argentinian’s case was preceded by the equally astonishing case of Wayne Gretzky: The Canadian considered ice hockey as a rather slow game and was the best player in the sport’s history. Whether Messi’s and Gretzky’s motor neurons fire faster, (inter)act differently or whether other mechanisms are at (inter)play warrants targeted research. A further explanation for such dominance of football and ice hockey, respectively, could be that both athletes “buy time”: To this end, automized motor skills may allow their predictive brains to make better use of time than other players to read the games and plan ahead. Deconstructing predictive minds of outperforming individuals like Gretzky and Messi could provide unique options to elucidate how differential time perception may make performances in athletes, and beyond, more swift and more efficient.  相似文献   

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The maximum likelihood and Bayesian methods are based on parametric models of character evolution. They assume that if we know these models as well as distribution of character states in studied organisms, we can infer the probability of different phylogenetic trajectories leading from ancestors to modern forms. In fact, these methods are mathematized variants of the traditional Haeckel’s approach to phylogeny reconstruction. In contrast to classical and parsimonious cladistics, they infer phylogenies without such limitations as necessity of strictly dichotomous evolution, exclusion of plesiomorphic characters, and acceptance of only holophyletic taxa. They assume that evolution may be reticulated, any homologous characters—both apomorphic and plesiomorphic—can be used for inferring phylogenies, and interpretation of evolutionary lineages as taxa is optional. Thus, the main difference between the new and more traditional approaches to phylogeny reconstruction lies not in the characters used (molecular or morphological) but in the methodology of analysis. It must be admitted that a revolution began in phylogenetics 10–20 years ago. However, the fundamental changes in phylogenetics have been carried out so calmly and neatly by the people who started this revolution, that many systematists still do not realize their importance.  相似文献   

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Mango (Mangifera indica L.) introductions to Florida began in 1861 with the importation of ’No. 11’, a polyembryonic, seed-propagated (nucellar) cultivarfrom Cuba. In the 1880s a collection of Cuban mangos was established near Bradenton. One resulting popular cultivar was ’Turpentine’, now widely used as a rootstock. The U. S. Department of Agriculture introduced ’Mulgoba’, an improved cultivarfrom India, in 1889. Other mangos were later brought from India, Vietnam, the Philippines, Thailand, Israel, Australia and Kenya. Related Mangifera species were collected in East Malaysian Borneo in 1990. Inasmuch as the breeding system of Mangifera favors outcrossing, the proximity of numerous genotypes of disparate geographic origin in Florida has made that state a secondary center of diversity for the mango and enabled it to make a unique contribution to the fruit industry.  相似文献   

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Parkinson’s disease (PD) is the most common movement disorder. The neuropathology is characterized by the loss of dopamine neurons in the substantia nigra pars compacta. Transplants of fetal/embryonic midbrain tissue have exhibited some beneficial clinical effects in open-label trials. Neural grafting has, however, not become a standard treatment for several reasons. First, the supply of donor cells is limited, and therefore, surgery is accompanied by difficult logistics. Second, the extent of beneficial effects has varied in a partly unpredictable manner. Third, some patients have exhibited graft-related side effects in the form of involuntary movements. Fourth, in two major double-blind placebo-controlled trials, there was no effect of the transplants on the primary endpoints. Nevertheless, neural transplantation continues to receive a great deal of interest, and now, attention is shifting to the idea of using stem cells as starting donor material. In the context of stem cell therapy for PD, stem cells can be divided into three categories: neural stem cells, embryonic stem cells, and other tissue-specific types of stem cells, e.g., bone marrow stem cells. Each type of stem cell is associated with advantages and disadvantages. In this article, we review recent advances of stem cell research of direct relevance to clinical application in PD and highlight the pros and cons of the different sources of cells. We draw special attention to some key problems that face the translation of stem cell technology into the clinical arena.  相似文献   

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Key message

This study is the first to quantify tree water use below 50°S. Tree morphology differs markedly among the two investigated species, reflecting adjustment to different environmental cues.

Abstract

A pronounced environmental gradient dictates the dominance of Nothofagus in the foothills on the eastern side of the Andes Mountains in Patagonia, Argentina. Below 50° southern latitude, open forests of Nothofagus antarctica (ñire) dominate the landscape towards the Patagonian steppe where annual rainfall is low. With increasing rates of annual rainfall, corresponding with an increase in elevation, closed forests of N. pumilio (lenga) replace those of ñire. During a short-term study we assessed differences in stand structure and examined environmental, structural and functional traits related to tree water use of ñire and lenga. Sap velocity reached similar maximum rates (95–100 L m?2 sapwood h?1), but whole-tree water use (Q) was significantly lower in ñire (8–13 L day?1 tree?1) compared to lenga (20–90 L day?1 tree?1) resulting in lower stand transpiration (ñire: 0.51 mm day?1; lenga: 3.42 mm day?1) despite similar tree densities. Related to this, wind speed had a particularly significant impact on Q of ñire, but not lenga. The ratio of leaf area to sapwood area (A L/A S) clearly identified ñire to be more structurally proficient at conserving water. While stem diameter (DBH) and crown area (A C) were well related in both species, only lenga exhibited relationships between variables related to tree allometry and physiology (A C/Q, DBH/Q). Our results provide the first ecophysiological characterization of the two Nothofagus species that define important and widespread ecosystems in southern Patagonia (not only below 50°S), and provide useful data to scale water use of both species from tree to stand.  相似文献   

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The current landscape of cancer biomarkers is changing rapidly, with new and exciting developments. With the advances of proteomic technologies, many potential cancer biomarkers have been discovered. However, the number of new cancer biomarkers cleared or approved by the US FDA is rather limited. Although technological advances are important, clearly defining intended use, good study design and appropriate patient specimens are critical for the success of FDA approval. While obtaining FDA clearance/approval for newly developed and clinically useful cancer biomarkers has been slow, the reward for patient care could be enormous.  相似文献   

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Hong Kong is famous as a bustling harbour and financial centre, with a dense burgeoning population impacting its coastal environment. Yet, away from the skyscrapers and the pressures of anthropogenic influence, Hong Kong supports a rich marine biodiversity, including corals and mangrove communities. Despite having a small marine area (1651 km2), a total of 5943 marine species have been recorded in Hong Kong waters. Most of these species were reported during the 1980s and 1990s, but new species continue to be discovered, and ~6500 species are estimated. Even though Hong Kong’s marine area is only ~0.03 % of that of China, the number of marine species recorded in Hong Kong already accounts for ~26 % of the total recorded in China. Hong Kong also contributes to a considerable amount (>30 %) of the species records for several taxa including amphipods, cephalopods, polychaetes and fish in the South China Sea, and ~29 % of the hermit crab species in the largest global marine species database, the World Register of Marine Species. These findings demonstrate the rich marine biota found in Hong Kong, which probably reflects Hong Kong’s location within the fringes of the world’s marine biodiversity hotspot.  相似文献   

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Mei S  Liu J  Zhao M  Wang W  Wang Y  Wu G  Zheng M  Peng S 《Molecular bioSystems》2011,7(9):2664-2669
Antifibrinolytic therapy during major complex surgery could reduce blood loss and allogeneic transfusion. Novel antagonists of the plasminogen activator and the corresponding model system are of clinical importance. In this paper (1S,2'S,3S)-1-[2-(S)-carboxylindolemethylenemethineaminoeth-1-yl]-2,3,4,5-tetrahydropyrolo[1,2:1,6]pyrazino[3,4:2,3]-1,2,3,4-tetrahydrocarboline-2,5-dione (CIPPC) was presented as a novel antagonist of plasminogen activator, and its blood coagulation and action mechanism were investigated by using a model system which consisted of a mouse-tail bleeding assay, in vitro and in vivo fibrinolysis inhibition assays, a thrombus formation assay and a plasminogen (PLG) electrophoresis assay.  相似文献   

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This article traces a critical change in the professional therapy of posttraumatic stress disorder (PTSD): from treatment of a disorder borne by individuals to treatment of an anticipated disorder to be prevented by fortifying the entire population. A community resilience program in the city of Sderot in southern Israel, which has been subjected to Qassam rockets by its Palestinian neighbors across the border, serves as our case study. Drawing on an ethnographic study of this new therapeutic program, we analyze how the social body that the professionals attempt to immunize against trauma was treated. In particular, we follow the various practices used to expand the clinical. We found that the population was split into several groups on a continuum between the clinical and the preclinical, each receiving different treatment. Moreover, the social body managed according to this new form of PTSD was articulated through ethnic and geopolitical power relations between professionals from the country’s center and professionals from its periphery, and between the professionals and the city’s residents. Finally, we discuss how this Israeli case compares with other national sites of the growing globalization of PTSD, like Bali, Haiti and Ethiopia, which anthropologists have been exploring in recent years.  相似文献   

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Libraries of dibasic compounds designed around the molecular scaffold of the DA(2)/β(2) dual agonist sibenadet (Viozan?) have yielded a number of promising starting points that have been further optimised into novel potent and selective target molecules with required pharmacokinetic properties. From a shortlist, 31 was discovered as a novel, high potency, and highly efficacious β(2)-agonist with high selectivity and a duration of action commensurable with once daily dosing.  相似文献   

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The first event of photosynthesis is the harvesting of solar energy by a large array of pigments. These pigments are coordinated to proteins that organize them to assure efficient excitation energy transfer. The protein plays an essential role in tuning the spectroscopic properties of the pigments, by determining their site energy and/or by favoring pigment-pigments interactions. Here we investigate how the protein modulates the pigment properties by using a single-point-mutation approach. We monitor changes in the low-energy absorption/emission band of Lhca4, which is well separated from the bulk absorption and thus represents an attractive model system. Moreover, it was recently shown that Lhca4 exists in at least two conformations, a dominating one emitting at 720nm and a second one emitting at 685nm (Kruger et al. PNAS 2011). Here we show that a single amino-acid substitution (from Asn to Gln, which are both chlorophyll-binding residues and only differ for one C-C bond), moves the equilibrium almost completely towards the 685-nm conformation. This indicates that small changes in the protein can have a large effect on the properties of the pigments. We show that His99, which was suggested to coordinate a red-absorbing chlorophyll (Melkozernov and Blankenship, JBC 2003), is not a chlorophyll ligand. We also show that single amino-acid substitutions nearby the chlorophylls allow to tune the emission spectrum of the pigments over a wide range of wavelengths and to modulate the excited-state lifetimes of the complex. These findings are discussed in the light of previously proposed non-photochemical quenching models.  相似文献   

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This work describes a practical way to optimize the high level of the chef creativity to produce rational approaches to food design. It is particularly focused on the preparation of two dishes: bubbly juice and false skin. For the first dish, three samples were prepared with egg white protein (EWP) and xanthan gum at pH 4.6 and pH 7.0. At pH 4.6 (isoelectric point), there were substantial differences of the interfacial dilational modulus of EWP when xanthan gum was added. At 1 mg/ml xanthan, the system showed a very strong interface (high viscoelasticity) compared to the other samples. Measuring half drainage time revealed which samples were the most stable. The properties discussed were related to stability. For the false skin dish, edible films were made by gelatin extracted from cod skins (A solution) and a mixture of cod skin gelatin and commercial gelatin (AG solution). The results showed that tensile strength (TS) of gelatin films increases almost by 25%, elongation at break (EAB) by 14%, and the Young modulus (E) by almost 100% when increasing protein concentration. To confirm water plasticizer effect, the results were compared to a gelatin film made with 30% glycerol (plasticizer). Water content affects to a great extent the mechanical properties of the films. Finally, images of the dishes are presented in order to have a full view of the purpose and the results obtained. This research has been supported by the Department of Agriculture and Fisheries from the Basque Government. This work was presented at the conference Delivery of Functionality in Complex Food Systems, Amherst, USA, October, 2007.  相似文献   

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The non-Mendelian sporadic Alzheimer's disease (AD) is the most frequent form of dementia diagnosed worldwide. The most important risk factor to develop sporadic AD is aging itself. Next to hyperphosphorylated Tau, intracellular amyloid beta (A?) oligomers are known to initiate a cascade of pathological events ranging from mitochondrial dysfunction, synaptic dysfunction, oxidative stress, and loss of calcium regulation, to inflammation. All these events are considered to play an important role in the progressive loss of neurons. The molecular mechanisms determining the balance between A? production and clearance during the progression of the disease are not well understood. Furthermore, there is cumulating evidence that A? formation impairs mitochondrial function and that mitochondrial dysfunction is an early event in the pathogenesis of AD. On the other hand, mitochondrial dysfunction, in particular increased formation of mitochondrially derived reactive oxygen species, promote A? formation. Here, we review these latest findings linking mitochondrial dysfunction and A? formation. We propose that mitochondrial dysfunction, which is well-known to increase with age, is an initial trigger for A? production. As A? itself further accelerates mitochondrial dysfunction and oxidative stress, its formation is self-stimulated. Taken together, a vicious cycle is initiated that originates from mitochondrial dysfunction, implying that AD can be viewed as an age-associated mitochondrial disorder. The proposed mechanism sheds new light on the pathophysiological changes taking place during the progression of AD as well as in the aging process.  相似文献   

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