Available online 31 July 2008

We consider two varieties associated to a web of quadrics W in P. One is the base locus and the second one is the double cover of P branched along the determinant surface of W . We show that small resolutions of these varieties are Calabi-Yau manifolds. We compute their Betti numbers and show that they are not birational in the generic case. The main result states that if the base locus of W co...

We say that a computably enumerable (c.e.) degree b is a Lachlan nonsplitting base (LNB), if there is a computably enumerable degree a such that a > b, and for any c.e. degrees w,v ≤ a, if a ≤ w ∨ v ∨ b then either a ≤ w ∨ b or a ≤ v ∨ b. In this paper we investigate the relationship between bounding and nonbounding of Lachlan nonsplitting bases and the high /low hierarchy. We prove that there ...

OBJECTIVE To determine if there is a relationship between parental perception of neighborhood safety and overweight at the age of 7 years. DESIGN Cross-sectional analysis of the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development. SETTING Ten urban and rural US sites. PARTICIPANTS A total of 768 children selected via conditional random ...

Recent trends in field of wireless networks is setting up Wireless Sensor Networks that, senses specified parameter(s) related to environment; processes sensed data and wirelessly communicates it to a base station. Such networks open up a whole new range of applications, including precision agriculture, monitoring and tracking vehicles, animals and humans, battle-field surveillance, civil struc...

Bike Sharing Systems became popular in recent years to extend the public transportation network of cities or regions. Most research in this area focuses on finding the optimal locations for bike sharing stations. Still various approaches on how to operate such a system efficiently exist. The usefulness of a bike sharing system strongly depends on the user convenience which is directly connected...

execution of every planned program in cities has different process. process involves inhabitant's preferences, capacity of area or neighborhood, scale of people participation. after these strategies plans will prepared and executors apply them. planning in city scale considering potentials of area and participation of people is very important stage to eliminate undesirable appearances of c...

Wobble base pairs are critical in various physiological functions and have been linked to local structural perturbations in double-helical structures of nucleic acids. We report a 1.38-Å resolution crystal structure of an antiparallel octadecamer RNA double helix in overall A conformation, which includes a unique, central stretch of six consecutive wobble base pairs (W helix) with two G·U and f...

the purpose of this study was to develop sunless tanning cosmetic creams from green coffee beans. chlorogenic acid, which was extracted from green coffee beans, performed the change of the color of keratin in stratum corneum, used as active ingredient in the formulation. extracted chlorogenic acid from green coffee beans were incorporated into four cosmetic cream bases, and then the tanning eff...