7-Benzyl-2,7-diaza­spiro­[4.4]nonan-1-one

In the title compound, C14H18N2O, both the spiro-linked five-membered rings adopt envelope conformations, with a C atom as the flap in one ring and an N atom in the other. The dihedral angle between the two four-atom planes is 80.46 (8)°. In the crystal, the mol­ecules are linked by N—H⋯O hydrogen bonds to generate C(4) chains propagating in [010]

1-(4-Chloro­phen­yl)-3-(5-methyl-2-fur­yl)prop-2-en-1-one

The title compound, C14H11ClO2, was prepared from 4-chloro­hypnone and 5-methyl­furfural by an aldol condensation reaction. The dihedral angle formed between the two benzene rings is 7.71 (2)°. The crystal structure is stabilized by C—H⋯O inter­actions

3-(2-Fluoro­phen­yl)-1-(4-methoxy­phen­yl)prop-2-en-1-one

The title compound, C16H13FO2, was prepared from 4-methoxy­hypnone and 2-fluoro­benzophenone by a Claisen–Schmidt condensation reaction. The dihedral angle between the two benzene rings is 31.99 (2)°. In the crystal structure, mol­ecules are linked by weak inter­molecular C—H⋯O hydrogen bonds along [010]

5-tert-Butyl 3-ethyl 1-isopropyl-4,5,6,7-tetra­hydro-1H-pyrazolo­[4,3-c]pyridine-3,5-dicarboxyl­ate

In the title compound, C17H27N3O4, the six-membered ring adopts a half-chair conformation with the N atom and the adjacent methyl­ene C atom displaced by −0.391 (2) and 0.358 (2) Å, respectively, from the plane of the other four atoms. In the crystal, mol­ecules are linked by weak C—H⋯O inter­actions

N′-[1-(2-Fur­yl)ethen­yl]propanohydrazide

The title compound, C9H12N2O2, was prepared by the reaction of acetyl­furan and propionylhydrazine. The molecule, excluding H atoms, is approximately planar. The crystal structure is stabilized by inter­molecular N—H⋯O hydrogen bonds

6-Benzyl 4-ethyl 2-chloro-5,6,7,8-tetra­hydro­pyrido[4,3-d]pyrimidine-4,6-di­carboxyl­ate

In the title compound, C18H18ClN3O4, the dihedral angle between the pyrimidine ring and the N-bonded ester grouping is 56.27 (7)° and the dihedral angle between the aromatic rings is 11.23 (7)°

(3S,12R,20S,24R)-20,24-Ep­oxy­dammarane-3,12,25-triol

In the title mol­ecule, C30H52O4, the three six-membered rings are in chair conformations, the cyclo­pentane ring is in an envelope form and the tetra­hydro­furan ring has a conformation inter­mediate between half-chair and sofa. In the crystal, mol­ecules are linked by inter­molecular O—H⋯O hydrogen bonds into helical chains along [100]. Two intra­molecular O—H⋯O hydrogen bonds are also present. One C atom of the tetrahydrofuran ring and its attached H atoms are equally disordered over two sets of sites

N′-(4-Fluoro­benzyl­idene)acetohydrazide

The title compound, C9H9FN2O, was prepared by the reaction of 4-fluoro­benzophenone and acethydrazide. In the mol­ecule, all non-H atoms are essentially coplanar [r.m.s. deviation = 0.065 (2) Å]. In the crystal, mol­ecules are linked into centrosymmetric dimers by pairs of inter­molecular N—H⋯O hydrogen bonds

N′-[1-(4-Chloro­phen­yl)ethyl­idene]acetohydrazide

In the title compound, C10H11ClN2O, the dihedral angle between the acetohydrazide group and the aromatic ring is 33.76 (9)°. In the crystal, inversion dimers linked by pairs of N—H⋯O hydrogen bonds generate R 2 2(8) loops

Crossing at a Red Light: Behavior of Cyclists at Urban Intersections

To investigate the relationship between cyclist violation and waiting duration, the red-light running behavior of nonmotorized vehicles is examined at signalized intersections. Violation waiting duration is collected by video cameras and it is assigned as censored and uncensored data to distinguish between normal crossing and red-light running. A proportional hazard-based duration model is introduced, and variables revealing personal characteristics and traffic conditions are used to describe the effects of internal and external factors. Empirical results show that the red-light running behavior of cyclist is time dependent. Cyclist’s violating behavior represents positive duration dependence, that the longer the waiting time elapsed, the more likely cyclists would end the wait soon. About 32% of cyclists are at high risk of violation and low waiting time to cross the intersections. About 15% of all the cyclists are generally nonrisk takers who can obey the traffic rules after waiting for 95 seconds. The human factors and external environment play an important role in cyclists’ violation behavior. Minimizing the effects of unfavorable condition in traffic planning and designing may be an effective measure to enhance traffic safety