1,661 research outputs found
Flip Graphs of Degree-Bounded (Pseudo-)Triangulations
We study flip graphs of triangulations whose maximum vertex degree is bounded
by a constant . In particular, we consider triangulations of sets of
points in convex position in the plane and prove that their flip graph is
connected if and only if ; the diameter of the flip graph is .
We also show that, for general point sets, flip graphs of pointed
pseudo-triangulations can be disconnected for , and flip graphs of
triangulations can be disconnected for any . Additionally, we consider a
relaxed version of the original problem. We allow the violation of the degree
bound by a small constant. Any two triangulations with maximum degree at
most of a convex point set are connected in the flip graph by a path of
length , where every intermediate triangulation has maximum degree
at most .Comment: 13 pages, 12 figures, acknowledgments update
The Architectural Design Rules of Solar Systems based on the New Perspective
On the basis of the Lunar Laser Ranging Data released by NASA on the Silver
Jubilee Celebration of Man Landing on Moon on 21st July 1969-1994, theoretical
formulation of Earth-Moon tidal interaction was carried out and Planetary
Satellite Dynamics was established. It was found that this mathematical
analysis could as well be applied to Star and Planets system and since every
star could potentially contain an extra-solar system, hence we have a large
ensemble of exoplanets to test our new perspective on the birth and evolution
of solar systems. Till date 403 exoplanets have been discovered in 390
extra-solar systems. I have taken 12 single planet systems, 4 Brown Dwarf -
Star systems and 2 Brown Dwarf pairs. Following architectural design rules are
corroborated through this study of exoplanets. All planets are born at inner
Clarke Orbit what we refer to as inner geo-synchronous orbit in case of
Earth-Moon System. By any perturbative force such as cosmic particles or
radiation pressure, the planet gets tipped long of aG1 or short of aG1. Here
aG1 is inner Clarke Orbit. The exoplanet can either be launched on death spiral
as CLOSE HOT JUPITERS or can be launched on an expanding spiral path as the
planets in our Solar System are. It was also found that if the exo-planet are
significant fraction of the host star then those exo-planets rapidly migrate
from aG1 to aG2 and have very short Time Constant of Evolution as Brown Dwarfs
have. This vindicates our basic premise that planets are always born at inner
Clarke Orbit. This study vindicates the design rules which had been postulated
at 35th COSPAR Scientific Assembly in 2004 at Paris, France, under the title
,New Perspective on the Birth & Evolution of Solar Systems.Comment: This paper has been reported to Earth,Moon and Planets Journal as
MOON-S-09-0007
Fungal iron availability during deep seated candidiasis is defined by a complex interplay involving systemic and local events
Peer reviewedPublisher PD
Mineralization of sheep manure and its influence on lettuce production
Diversos resíduos orgânicos são utilizados na agricultura sem o adequado conhecimento da sua dinâmica de mineralização. Avaliou-se a mineralização de esterco de ovinos e sua influência na produção de alface. Utilizou-se o delineamento experimental de blocos ao acaso com três repetições. Foram utilizadas 25 t ha-1 como dose de esterco para cada um dos seguintes tratamentos: 1) esterco de ovinos que se alimentaram de feno de mandioca (PAM); 2) esterco de ovinos que se alimentaram de subproduto de ervilha (ERV); 3) esterco de ovinos que se alimentaram de feno de capim coast-cross (FCC); 4) esterco de ovinos que se alimentaram de subproduto de saccharina (SAC) e 5) solo sem aplicação de esterco (testemunha). Foi determinada semanalmente a respiração basal do solo, utilizada como indicador de mineralização da matéria orgânica. A massa fresca de alface foi avaliada como medida de produção. Os tratamentos ERV, FCC e SAC apresentaram ganhos de massa fresca na ordem de 68, 65 e 62% em relação à testemunha e de 43, 39 e 33% em relação ao PAM, respectivamente. A produção menor promovida pelo PAM, em relação às demais, pode ser explicada pela forma de mineralização da matéria orgânica que apresentou elevada respiração microbiana cinco dias após o transplantio, com acentuado declínio, nas medições subseqüentes, ao longo do ciclo da cultura. Os demais tratamentos apresentaram mineralização sincronizada com conseqüente aumento na produção de massa fresca.
____________________________________________________________________________________________________________ ABSTRACTSeveral organic wastes are used in agriculture with no precise knowledge about the mineralization dynamics of these materials. In this study the sheep manure mineralization and its influence on the lettuce production was evaluated. A randomized block design with three replications was used. Five treatments were studied using 25 t ha-1 as dose of manure: 1) sheep manure obtained from animals fed with cassava straw (PAM); 2) sheep manure obtained from animals fed with residue of pea crop (ERV); 3) sheep manure obtained from animals fed with Coast-Cross hay (FCC), 4) sheep manure obtained from animals fed with saccharin residue (SAC) and 5) soil without application of manure (control). Weekly the basal respiration was determined and used as an indicator of organic matter mineralization. Lettuce fresh mass was evaluated as a measure of production. Treatments ERV, FCC and SAC showed superior weight gains of 68, 65 and 62% compared to the control and 43, 39 and 33% compared to MAP, respectively. Lower production promoted by the MAP in relation to the other treatments can be explained by organic matter mineralization that showed a high microbial respiration five days after transplanting, with marked decline in subsequent measurements during the crop cycle. The other systems showed mineralization synchronized with the production increase of lettuce fresh mass
Transition of plasmodium sporozoites into liver stage-like forms is regulated by the RNA binding protein pumilio
Many eukaryotic developmental and cell fate decisions that are effected post-transcriptionally involve RNA binding proteins as regulators of translation of key mRNAs. In malaria parasites (Plasmodium spp.), the development of round, non-motile and replicating exo-erythrocytic liver stage forms from slender, motile and cell-cycle arrested sporozoites is believed to depend on environmental changes experienced during the transmission of the parasite from the mosquito vector to the vertebrate host. Here we identify a Plasmodium member of the RNA binding protein family PUF as a key regulator of this transformation. In the absence of Pumilio-2 (Puf2) sporozoites initiate EEF development inside mosquito salivary glands independently of the normal transmission-associated environmental cues. Puf2- sporozoites exhibit genome-wide transcriptional changes that result in loss of gliding motility, cell traversal ability and reduction in infectivity, and, moreover, trigger metamorphosis typical of early Plasmodium intra-hepatic development. These data demonstrate that Puf2 is a key player in regulating sporozoite developmental control, and imply that transformation of salivary gland-resident sporozoites into liver stage-like parasites is regulated by a post-transcriptional mechanism
Benefits and risks of the hormetic effects of dietary isothiocyanates on cancer prevention
The isothiocyanate (ITC) sulforaphane (SFN) was shown at low levels (1-5 µM) to promote cell proliferation to 120-143% of the controls in a number of human cell lines, whilst at high levels (10-40 µM) it inhibited such cell proliferation. Similar dose responses were observed for cell migration, i.e. SFN at 2.5 µM increased cell migration in bladder cancer T24 cells to 128% whilst high levels inhibited cell migration. This hormetic action was also found in an angiogenesis assay where SFN at 2.5 µM promoted endothelial tube formation (118% of the control), whereas at 10-20 µM it caused significant inhibition. The precise mechanism by which SFN influences promotion of cell growth and migration is not known, but probably involves activation of autophagy since an autophagy inhibitor, 3-methyladenine, abolished the effect of SFN on cell migration. Moreover, low doses of SFN offered a protective effect against free-radical mediated cell death, an effect that was enhanced by co-treatment with selenium. These results suggest that SFN may either prevent or promote tumour cell growth depending on the dose and the nature of the target cells. In normal cells, the promotion of cell growth may be of benefit, but in transformed or cancer cells it may be an undesirable risk factor. In summary, ITCs have a biphasic effect on cell growth and migration. The benefits and risks of ITCs are not only determined by the doses, but are affected by interactions with Se and the measured endpoint
The establishment of bonds between professional and patient in TB treatment: the performance of primary health care services in a city in the interior of São Paulo
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