User-Centered Evaluation of Adaptive and Adaptable Systems

Adaptive and adaptable systems provide tailored output to various users in various contexts. While adaptive systems base their output on implicit inferences, adaptable systems use explicitly provided information. Since the presentation or output of these systems is adapted, standard user-centered evaluation methods do not produce results that can be easily generalized. This calls for a reflection on the appropriateness of standard evaluation methods for user-centered evaluations of these systems. We have conducted a literature review to create an overview of the methods that have been used. When reviewing the empirical evaluation studies we have, among other things, focused on the variables measured and the implementation of results in the (re)design process. The goal of our review has been to compose a framework for user-centered evaluation. In the next phase of the project, we intend to test some of the most valid and feasible methods with an adaptive or adaptable system

Transmembrane segment (TMS) VIII of the Na+/citrate transporter CitS requires downstream TMS IX for insertion in the Escherichia coli membrane

The amino acid sequence of the sodium ion-dependent citrate transporter CitS of IL pneumoniae contains 12 hydrophobic stretches that could form membrane-spanning segments. A previous analysis of the membrane topology in Escherichia coli using the PhoA gene fusion technique indicated that only nine of these hydrophobic segments span the membrane, while three segments, Vb, VIII and IX were predicted to have a periplasmic location (Van Geest, IM., and Lolkema, J. S. (1996) J. Biol. Chem. 271, 25582-25589), A topology study of C-terminally truncated CitS molecules in dog pancreas microsomes revealed that the protein traverses the endoplasmic reticulum membrane 11 times. In agreement with the PhoA fusion data, segment Vb was predicted to have a periplasmic location, but, in contrast, segments VIII and IX were found to be membrane-spanning (Van Geest, M., Nilsson, I., von Heijne, G., and Lolkema, J, S, (1999) J. Biol, Chem. 274, 2816-2823),In the present study, using site-directed Cys labeling, the topology of segments VIII and IX in the fall-length CitS protein was determined in the E. coli membrane, Engineered cysteine residues in the loop between the two segments were accessible to a membrane-impermeable thiol reagent exclusively from the cytoplasmic side of the membrane, demonstrating that transmembrane segments (TMSs) VIII and M are both membrane-spanning. It follows that the folding of CitS in the E. cold and endoplasmic reticulum membrane is the same. Cysteine accessibility studies of CitS-PhoA fusion molecules dem; onstrated that in the E. coli membrane segment VIII is exported to the periplasm in the absence of the C-terminal CitS sequences, thus explaining why the PhoA fusions do not correctly predict the topology. An engineered cysteine residue downstream of TMS VIII moved from a periplasmic to a cytoplasmic location when the fusion protein containing TMSs I-VIII was extended with segment IX, Thus, downstream segment M is both essential and sufficient for the insertion of segment VIII of CitS in the E. coli membrane.</p

Kwaliteitsinformatie en de marktaandelen van IVF-centra

Sinds 1997 zijn de prestaties van IVF-centra op internet onderling vergelijkbaar. Zorggebruikers lijken de beschikbare kwaliteitsinformatie te gebruiken. IVF-centra in de Randstad met een hoger percentage doorgaande zwangerschappen hebben een groter marktaandeel

Price competition among Dutch sickness funds

In general, competition enhances efficiency. On the market for health insurance free market competition, however, has unwanted side-effects. The existence of asymmetrical information can lead to adverse selection and cream skimming. Adequate risk-adjustment removes the incentives for cream skimming and balances the negative consequences of adverse selection. In an attempt to enhance efficiency, the Dutch government in 1992 introduced price competition between social health insurers in combination with risk-adjusted capitation payments. Our estimation results indicate that this has not resulted in altering market shares. Relatively cheap insurers did not enlarge their market share at the expense of their relatively expensive competitors. The introduction of competition among social health insurers has not been the success the Dutch government hoped for. Experiences in Belgium and Germany show that the Dutch difficulties are not exceptional. When equity considerations are high valued features of a health insurance system, it is difficult to introduce competition. To enhance efficiency, we recommend that the current capitation formula should be refined and that the insurers should be given more room for selective contracting of health care providers

Using the deductible for patient channeling: did preferred providers gain patient volume?

In market-based health care systems, channeling patients to designated preferred providers can increase payer’s bargaining clout, other things being equal. In the unique setting of the new Dutch health care system with regulated competition, this paper evaluates the impact of a 1-year natural experiment with patient channeling on providers’ market shares. In 2009 a large regional Dutch health insurer designated preferred providers for two different procedures (cataract surgery and varicose veins treatment) and gave its enrollees a positive financial incentive for choosing them. That is, patients were exempted from paying their deductible when they went to a preferred provider. Using claims data over the period 2007–2009, we apply a difference-in-difference approach to study the impact of this channeling strategy on the allocation of patients across individual providers. Our estimation results show that, in the year of the experiment, preferred providers of varicose veins treatment on average experienced a significant increase in patient volume relative to non-preferred providers. However, for cataract surgery no significant effect is found. Possible explanations for the observed difference between both procedures may be the insurer’s selection of preferred providers and the design of the channeling incentive resulting in different expected financial benefits for both patient groups