197,021 research outputs found
Solving real-world ATSP instances by branch-and-cut
No full textRecently, Fischetti, Lodi and Toth [15] surveyed exact methods for the Asymmetric Traveling Salesman Problem (ATSP) and computationally compared branch-and-bound and branch-and-cut codes. The results of this comparison proved that branch-and-cut is the most effective method to solve hard ATSP instances. In the present paper the branch-and-cut algorithms by Fischetti and Toth [17] and by Applegate, Bixby, Chvátal and Cook [2] are considered and tested on a set of 35 real-world instances including 16 new instances recently presented in [12]. © Springer-Verlag Berlin Heidelberg 2003
Combining complete and partial cell suppression methodologies in statistical disclosure control
No full textThis paper combines the well-known Cell Suppression Methodology (herein called complete cell suppression) and a recently developed method (called partial cell suppression) presented in Fischetti and Salazar [1]. It proposes a unified new methodology with the best features of both and without some disadvantages of the single ones. Hence, this paper presents a new and more powerful cell suppression technique to protect sensitive cells in all kinds of tables. A background on Mathematical Programming guarantees the exact protection of the output against an external intruder while the loss of information is minimised
A Feasibility Pump Heuristic for General Mixed-Integer Problems
No full textAbstractFinding a feasible solution of a given Mixed-Integer Programming (MIP) model is a very important (NP-complete) problem that can be extremely hard in practice. Very recently, Fischetti, Glover and Lodi proposed a heuristic scheme for finding a feasible solution to general MIPs, called a Feasibility Pump (FP). According to the computational analysis reported by these authors, FP is indeed quite effective in finding feasible solutions of hard 0-1 MIPs. However, MIPs with general-integer variables seem much more difficult to solve by using the FP approach.In this paper we elaborate on the Fischetti–Glover–Lodi approach and extend it in two main directions, namely (i) handling as effectively as possible MIP problems with both binary and general-integer variables, and (ii) exploiting the FP information to drive a subsequent enumeration phase.Extensive computational results on large sets of test instances from the literature are reported, showing the effectiveness of our improved FP scheme for finding feasible solutions to hard MIPs with general-integer variables
Manuale pratico di oncologia. Fondamenti per il medico non oncologo- Costanzo Francesco; Cognetti Francesco; Benedetti Panici Pierluigi
No full textBenedetti Panici P, Di Donato V., Fischetti M, Lo Prete E, Musella A, Plotti F, Casorelli A, Bellati F (2011).
Capitoli: Carcinoma Dell' Endometrio.. arcinoma Epiteliale Dell’ovaio In: -. Manuale Pratico Di Oncologia Fondamenti Per Il Medico Non Oncologo
From Mixed-Integer Linear to Mixed-Integer Bilevel Linear Programming
No full textBilevel Optimization is a very challenging framework where two players (with different objectives) compete for the definition of the final solution. In this paper we address a generic mixed-integer bilevel linear program, i.e., a bilevel optimization problem where the objective functions and constraints are all linear, and some variables are required to take integer values. We briefly describe some main ingredients of a branch-and-cut general-purpose framework for the exact solution (under appropriate assumptions) of mixed-integer bilevel linear programs
NOCICEPTIN/ORPHANIN FQ RECEPTOR LIGANDS: PHARMACOLOGICAL STUDIES
No full textThe neuropeptide nociceptin/orphanin FQ (N/OFQ) selectively binds and activates the
N/OFQ peptide (NOP) receptor. At cellular level N/OFQ inhibits cAMP accumulation and Ca2+
conductance and stimulates K+ currents. N/OFQ regulates several biological functions both at
central (pain, locomotion, memory, emotional responses, food intake) and peripheral (airways,
cardiovascular, genitourinary and gastrointestinal systems) sites. Potent and selective NOP ligands
are now required for investigating the roles played by NOP receptors in pathophysiological studies
and for firmly defining the therapeutic indications of NOP receptor ligands.
A novel assay to screen NOP receptor ligands has been validated with a large panel of
ligands: the Gaqi5 chimeric protein has been used to force the NOP receptor to signal through the
Ca2+ pathway in CHO cells. [Ca2+]i levels were monitored using the fluorometer FlexStation II.
Data are in general agreement with classical Gi driven assay systems.
The NOP peptide partial agonist, ZP120 was extensively characterized in vitro using
electrically stimulated isolated tissues (mouse and rat vas deferens) and in vivo with the tail
withdrawal assay. The selective involvement of the NOP receptor in the actions of ZP120 has been
demonstrated in NOP(-/-) mice studies.
A detailed pharmacological characterization of the recently identified non-peptide antagonist
Compound 24 has been performed. Moreover in the context of a SAR study on Compound 24, a
novel NOP ligand named Compound 35 was identified. Compound 24 and Compound 35 bound the
human recombinant NOP receptor expressed in CHOhNOP cell membranes with high affinity (pKi
values 9.62 and 9.14, respectively). Our findings derived from functional studies on CHOhNOP and
bioassay studies on native receptors demonstrated that Compound 24 and Compound 35 behave as
potent, competitive and selective non-peptide NOP antagonists. Finally, the NOP antagonist
properties of Compound 24 have been confirmed in vivo in the mouse tail withdrawal assay
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