Juan Hernandez | Universidad del Magdalena (original) (raw)
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Papers by Juan Hernandez
Applied Thermal Engineering, 1999
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This paper gives a tutorial on the techniques and reference models used in digital watermarking. ... more This paper gives a tutorial on the techniques and reference models used in digital watermarking. Distorsions, attacks and applications are described in some detail. Finally, the need for benchmarking is discussed
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IEEE Transactions on Image Processing, 2000
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Signal Processing, 2001
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Journal of Applied Microbiology, 1991
Counts of Escherichia coli, faecal streptococci and enterococci were made on faecal specimens fro... more Counts of Escherichia coli, faecal streptococci and enterococci were made on faecal specimens from human and animal origin and urban raw sewage waters, with microtiter plates containing selective substances. Escherichia coli was more numerous than faecal streptococci and enterococci in 80% of the samples regardless of the origin. Consequently the use of the ratio E. coli/faecal streptococci to distinguish human from animal origin of faecal pollution is questionable. Enterococcus faecalis was predominant in human and poultry faeces, Streptococcus bovis was typical of the bovine faeces and to a lesser extent also of pig faeces whereas Enterococcus durans, Ent. hirae and Ent. faecium did not characterize any faecal source. Streptococcus bovis could be distinguished in the mictrotiter plate by its inability to reduce triphenyl tetrazolium chloride (TTC) in the medium.
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Science, 2004
The circumrotation of a submolecular fragment in either direction in a synthetic molecular struct... more The circumrotation of a submolecular fragment in either direction in a synthetic molecular structure is described. The movement of a small ring around a larger one occurs through positional displacements arising from biased Brownian motion that are kinetically captured and then directionally released. The sense of rotation is governed solely by the order in which a series of orthogonal chemical transformations is performed. The minimalist nature of the [2]catenane flashing ratchet design permits certain mechanistic comparisons with the Smoluchowski-Feynman ratchet and pawl. Even when no work has to be done against an opposing force and no net energy is used to power the motion, a finite conversion of energy is intrinsically required for the molecular motor to undergo directional rotation. Nondirectional rotation has no such requirement.
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Bookmarks Related papers MentionsView impact
Applied Thermal Engineering, 1999
Bookmarks Related papers MentionsView impact
This paper gives a tutorial on the techniques and reference models used in digital watermarking. ... more This paper gives a tutorial on the techniques and reference models used in digital watermarking. Distorsions, attacks and applications are described in some detail. Finally, the need for benchmarking is discussed
Bookmarks Related papers MentionsView impact
IEEE Transactions on Image Processing, 2000
Bookmarks Related papers MentionsView impact
Signal Processing, 2001
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Journal of Applied Microbiology, 1991
Counts of Escherichia coli, faecal streptococci and enterococci were made on faecal specimens fro... more Counts of Escherichia coli, faecal streptococci and enterococci were made on faecal specimens from human and animal origin and urban raw sewage waters, with microtiter plates containing selective substances. Escherichia coli was more numerous than faecal streptococci and enterococci in 80% of the samples regardless of the origin. Consequently the use of the ratio E. coli/faecal streptococci to distinguish human from animal origin of faecal pollution is questionable. Enterococcus faecalis was predominant in human and poultry faeces, Streptococcus bovis was typical of the bovine faeces and to a lesser extent also of pig faeces whereas Enterococcus durans, Ent. hirae and Ent. faecium did not characterize any faecal source. Streptococcus bovis could be distinguished in the mictrotiter plate by its inability to reduce triphenyl tetrazolium chloride (TTC) in the medium.
Bookmarks Related papers MentionsView impact
Science, 2004
The circumrotation of a submolecular fragment in either direction in a synthetic molecular struct... more The circumrotation of a submolecular fragment in either direction in a synthetic molecular structure is described. The movement of a small ring around a larger one occurs through positional displacements arising from biased Brownian motion that are kinetically captured and then directionally released. The sense of rotation is governed solely by the order in which a series of orthogonal chemical transformations is performed. The minimalist nature of the [2]catenane flashing ratchet design permits certain mechanistic comparisons with the Smoluchowski-Feynman ratchet and pawl. Even when no work has to be done against an opposing force and no net energy is used to power the motion, a finite conversion of energy is intrinsically required for the molecular motor to undergo directional rotation. Nondirectional rotation has no such requirement.
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact