Sequencing games without initial order

In this note we study uncertainty sequencing situations, i.e., one-machine sequencing situations in which no initial order is specified. We associate cooperative games with these sequencing situations, study their core, and provide links with the classic sequencing games introduced by Curiel et al. (Eur J Oper Res 40:344–351, 1989). Moreover, we propose and characterize two simple cost allocation rules for uncertainty sequencing situations with equal processing times.     

Kemp elimination in membrane mimetic reaction media: probing catalytic properties of catanionic vesicles formed from double-tailed amphiphiles

The rate-determining deprotonation of 5-nitrobenzisoxazole (Kemp elimination) by hydroxide is efficiently catalyzed by vesicles formed from dimethyldioctadecylammonium chloride (C(18)()C(18)()(+)()). Gradual addition of sodium didecyl phosphate (C(10)()C(10)()(-)()) leads to the formation of catanionic vesicles, which were characterized by cryo-electron microscopy, and their main phase transition temperatures (DSC) and zeta-potentials. Increasing percentages of C(10)()C(10)()(-)() in the vesicular bilayers decrease the catalysis of the Kemp elimination. A detailed kinetic analysis, supported by consideration of substrate binding site polarities and counterion binding percentages, suggest that the catalytic effects of C(18)()C(18)()(+)()/C(10)()C(10)()(-)() catanionic vesicles are primarily determined by the binding of catalytically active hydroxide ions to the vesicular surface area. The formation of neutral microdomains between 10 and 30 mol % of C(10)()C(10)()(-)() in the bilayer, as revealed by DSC, is not apparent from the catalytic effects found for these vesicles. Interestingly, the catalytic effects observed for 50 mol % C(10)()C(10)()(-)() in the catanionic vesicles indicate an asymmetric distribution of C(18)()C(18)()(+)() and C(10)()C(10)()(-)() over the bilayer leaflets. The overall kinetic results illustrate the highly complex mix of factors which determines catalytic effects on reactions occurring in biological cell membranes.     

On the consistency of deferred acceptance when priorities are acceptant substitutable

In the context of resource allocation on the basis of responsive priorities, Ergin (2002) identifies a necessary and sufficient condition for the deferred acceptance rule to satisfy a consistency principle. In this note, we extend this result to the domain of substitutable priorities, complementing results of Kojima and Manea (2010) and Kumano (2009).     

The Kemp elimination in membrane mimetic reaction media. Probing catalytic properties of cationic vesicles formed from a double-tailed amphiphile and linear long-tailed alcohols or alkyl pyranosides

Vesicles formed from synthetic, double-tailed amphiphiles are often used as mimics for biological membranes. However, biological membranes are a complex mixture of various compounds. In the present paper we describe a first attempt to study the importance of additives on vesicular catalysis. The rate-determining deprotonation of 5-nitrobenzisoxazole (Kemp elimination) by hydroxide ion is efficiently catalysed by vesicles formed from dimethyldi-n-octadecylammonium chloride (C(18)C(18)(+)) as a result of (partial) dehydration of the reactants (especially the hydroxide ion) at the vesicular binding sites. Gradual addition of linear alcohols, such as n-decanol (C(10)OH), n-octadecanol (C(18)OH) and batyl alcohol (C(18)GlyOH) leads to a decrease in the observed catalysis. By contrast, gradual addition of oleyl alcohol, n-dodecyl-beta-glucoside (C(12)Glu) and n-dodecyl-beta-maltoside (C(12)Mal) leads to an increase in the observed catalysis. A detailed kinetic analysis, taking into account substrate binding site polarities, counterion binding percentages and binding affinity of the kinetic probe, suggests that the catalytic changes depend strongly on subtle changes in the structure of the additive. Whereas the C(12)Glu-induced effect can be explained by an increase in the vesicular rate constant, the effect of C(12)Mal can only be explained by an increase in the binding constant of the kinetic probe. However, for these pyranoside-containing vesicles others factors, such as a more extensive dehydration of the hydroxide ion, and micelle formation have to be considered. For the linear alcohols, besides a decrease in the counterion binding, changes in the vesicular rate constant and the binding constant should be taken into account. These two parameters change to a different extent for the different alcohols. The kinetic analysis is supported by differential scanning calorimetry (DSC), E(T)(30) absorbance data and Nile Red, Laurdan, ANS and pyrene fluorescence measurements.The overall kinetic results are illustrative for the highly complex mix of factors which determines catalytic effects on reactions occurring in biological cell membranes.     

Fair and efficient student placement with couples

We study situations of allocating positions to students based on priorities. An example is the assignment of medical students to hospital residencies on the basis of entrance exams. For markets without couples, e.g., for undergraduate student placement, acyclicity is a necessary and sufficient condition for the existence of a fair and efficient placement mechanism (Ergin in Econometrica 70:2489–2497, 2002). We show that in the presence of couples acyclicity is still necessary, but not sufficient. A second necessary condition is priority-togetherness of couples. A priority structure that satisfies both necessary conditions is called pt-acyclic. For student placement problems where all quotas are equal to one we characterize pt-acyclicity and show that it is a sufficient condition for the existence of a fair and efficient placement mechanism. If in addition to pt-acyclicity we require reallocation- and vacancy-fairness for couples, the so-called dictator- bidictator placement mechanism is the unique fair and efficient placement mechanism. Finally, for general student placement problems, we show that pt-acyclicity may not be sufficient for the existence of a fair and efficient placement mechanism. We identify a sufficient condition such that the so-called sequential placement mechanism produces a fair and efficient allocation.      

Distribution center consolidation games

We study a location-inventory model to analyze the impact of consolidation of distribution centers on facility and inventory costs. We introduce a cooperative game and show that when demand processes are i.i.d. the core is non-empty, i.e., consolidation allows for a stable division of the minimal costs.