Single-leg airline revenue management with overbooking

Airline revenue management is about identifying the maximum revenue seat allocation policies. Since a major loss in revenue results from cancellations and no-show passengers, over the years overbooking has received a significant attention in the literature. In this study, we propose new models for static and dynamic single-leg overbooking problems. In the static case, we introduce computationally tractable models that give upper and lower bounds for the optimal expected revenue. In the dynamic case, we propose a new dynamic programming model, which is based on two streams of arrivals. The first stream corresponds to the booking requests and the second stream represents the cancellations. We also conduct simulation experiments to illustrate the proposed models and the solution methods

Faith without hope is dead: moral arguments and the theological virtues

It is well-known that Kant defends a conception of God and the final end of our moral striving, called the highest good. In this article, I outline Kant's argument for why we ought to have faith in God and hope for the highest good, and argue that the Kantian argument can be extended in such a way as to show the unity of the theological virtues. This feature of the Kantian account can then have ramifications in further questions regarding the relationship of faith and moral action

Performance of normal young adults in two temporal resolution tests

BACKGROUND: temporal auditory processing is defined as the perception of sound or of sound alteration within a restricted time interval and is considered a fundamental ability for the auditory perception of verbal and non verbal sounds, for the perception of music, rhythm, periodicity and in the discrimination of pitch, duration and of phonemes. AIM: to compare the performance of normal Brazilian adults in two temporal resolution tests: the Gaps-in-Noise Test (GIN) and the Random Gap Detection Test (RGDT), and to analyze potential differences of performance in these two tests. METHOD: twenty-five college students with normal hearing (11 males and 14 females) and no history of educational, neurological and/or language problems, underwent the GIN and RGDT at 40dB SL. RESULTS: statistically significant gender effects for both tests were found, with female participants showing poorer performance on both temporal processing tests. In addition, a comparative analysis of the results obtained in the GIN and RGDT revealed significant differences in the threshold measures derived for these two tests. In general, significantly better gap detection thresholds were observed for both male and female participants on the GIN test when compared to the results obtained for the RGDT. CONCLUSION: male participants presented better performances on both RGDT and GIN, when compared to the females. There were no differences in performance between right and left ears on the GIN test. Participants of the present investigation, males and females, performed better on the GIN when compared to the RGDT. The GIN presented advantages over the RGDT, not only in terms of clinical validity and sensibility, but also in terms of application and scoring.TEMA: o processamento auditivo temporal se refere a percepção de um evento sonoro ou de uma alteração no mesmo, dentro de um intervalo definido de tempo e é considerado uma habilidade fundamental na percepção auditiva de sons verbais e não verbais, na percepção de música, ritmo e pontuação e na discriminação de pitch, de duração e de fonemas. OBJETIVO: realizar um estudo comparativo do desempenho de adultos jovens normais nos testes de resolução temporal, Random Gap Detection Test (RGDT) e Gaps-in-Noise (GIN) e analisar diferenças entre esses dois métodos de avaliação. MÉTODO: 25 universitários, 11 homens e 14 mulheres, com audição normal e sem histórico de alterações educacionais, neurológicas e/ou linguagem, foram submetidos ao RGDT e ao GIN, a 40dB NS. RESULTADO: observou-se diferença estatisticamente significante entre os sexos sendo que as mulheres apresentaram pior desempenho nos dois testes. No estudo comparativo dos resultados do RGDT e GIN, observaram-se diferenças significativas no desempenho da amostra. De maneira geral, os limiares de detecção de gap no teste GIN foram melhores do que os limiares obtidos no RGDT. CONCLUSÃO: o sexo masculino teve melhor desempenho tanto no teste RGDT quanto no GIN, quando comparado ao feminino. Além disso, não houve diferença significante nas repostas do GIN nas orelhas direita e esquerda. Os sujeitos deste estudo tiveram melhor desempenho no teste GIN, quando comparado ao RGDT, tanto no sexo masculino quanto no feminino. Portanto, o teste GIN apresentou vantagens sobre o RGDT não apenas quanto à sua validade e sensibilidade, mas também com relação a sua aplicação e correção dos resultados.University of Massachusetts Amherst Department of Communication DisordersUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaFaculdades Metropolitanas UnidasPurdue UniversityUniversity of Massachusetts Department of Communication DisordersUNIFESP, EPMSciEL

A novel isolator-based system promotes viability of human embryos during laboratory processing

In vitro fertilisation (IVF) and related technologies are arguably the most challenging of all cell culture applications. The starting material is a single cell from which one aims to produce an embryo capable of establishing a pregnancy eventually leading to a live birth. Laboratory processing during IVF treatment requires open manipulations of gametes and embryos, which typically involves exposure to ambient conditions. To reduce the risk of cellular stress, we have developed a totally enclosed system of interlinked isolator-based workstations designed to maintain oocytes and embryos in a physiological environment throughout the IVF process. Comparison of clinical and laboratory data before and after the introduction of the new system revealed that significantly more embryos developed to the blastocyst stage in the enclosed isolator-based system compared with conventional open-fronted laminar flow hoods. Moreover, blastocysts produced in the isolator-based system contained significantly more cells and their development was accelerated. Consistent with this, the introduction of the enclosed system was accompanied by a significant increase in the clinical pregnancy rate and in the proportion of embryos implanting following transfer to the uterus. The data indicate that protection from ambient conditions promotes improved development of human embryos. Importantly, we found that it was entirely feasible to conduct all IVF-related procedures in the isolator-based workstations

Ultrathin 2 nm gold as ideal impedance-matched absorber for infrared light

Thermal detectors are a cornerstone of infrared (IR) and terahertz (THz) technology due to their broad spectral range. These detectors call for suitable broad spectral absorbers with minimalthermal mass. Often this is realized by plasmonic absorbers, which ensure a high absorptivity butonly for a narrow spectral band. Alternativly, a common approach is based on impedance-matching the sheet resistance of a thin metallic film to half the free-space impedance. Thereby, it is possible to achieve a wavelength-independent absorptivity of up to 50 %, depending on the dielectric properties of the underlying substrate. However, existing absorber films typicallyrequire a thickness of the order of tens of nanometers, such as titanium nitride (14 nm), whichcan significantly deteriorate the response of a thermal transducers. Here, we present the application of ultrathin gold (2 nm) on top of a 1.2 nm copper oxide seed layer as an effective IR absorber. An almost wavelength-independent and long-time stable absorptivity of 47(3) %, ranging from 2 $\mu$m to 20 $\mu$m, could be obtained and is further discussed. The presented gold thin-film represents analmost ideal impedance-matched IR absorber that allows a significant improvement of state-of-the-art thermal detector technology

On the Generalizability of Experimental Results

The age-old question of the generalizability of the results of experiments that are conducted in artificial laboratory settings to more realistic inferential and decision making situations is considered in this paper. Conservatism in probability revision provides an example of a result that 1) has received wide attention, including attention in terms of implications for real-world decision making, on the basis of experiments conducted in artificial settings and 2) is now apparently thought by many to be highly situational and not at all a ubiquitous phenomenon, in which case its implications for real-world decision making are not as extensive as originally claimed. In this paper we consider the questions of generalizations from the laboratory to the real world in some detail, both within the context of the experiments regarding conservatism and within a more general context. In addition, we discuss some of the difficulties inherent in experimentation in realistic settings, suggest possible procedures for avoiding or at least alleviating such difficulties, and make a plea for more realistic experiments

Haptic search with finger movements: using more fingers does not necessarily reduce search times

Two haptic serial search tasks were used to investigate how the separations between items, and the number of fingers used to scan them, influence the search time and search strategy. In both tasks participants had to search for a target (cross) between a fixed number of non-targets (circles). The items were placed in a straight line. The target’s position was varied within blocks, and inter-item separation was varied between blocks. In the first experiment participants used their index finger to scan the display. As expected, search time depended on target position as well as on item separation. For larger separations participants’ movements were jerky, resembling ‘saccades’ and ‘fixations’, while for the shortest separation the movements were smooth. When only considering time in contact with an item, search times were the same for all separation conditions. Furthermore, participants never continued their movement after they encountered the target. These results suggest that participants did not use the time during which they were moving between the items to process information about the items. The search times were a little shorter than those in a static search experiment (Overvliet et al. in Percept Psychophys, 2007a), where multiple items were presented to the fingertips simultaneously. To investigate whether this is because the finger was moving or because only one finger was stimulated, we conducted a second experiment in which we asked participants to put three fingers in line and use them together to scan the items. Doing so increased the time in contact with the items for all separations, so search times were presumably longer in the static search experiment because multiple fingers were involved. This may be caused by the time that it takes to switch from one finger to the other

ER and HER2 expression are positively correlated in HER2 non-overexpressing breast cancer

PMCID: PMC3446380This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

A Dynamic Model of Interactions of Ca^(2+), Calmodulin, and Catalytic Subunits of Ca^(2+)/Calmodulin-Dependent Protein Kinase II

During the acquisition of memories, influx of Ca^(2+) into the postsynaptic spine through the pores of activated N-methyl-D-aspartate-type glutamate receptors triggers processes that change the strength of excitatory synapses. The pattern of Ca^(2+) influx during the first few seconds of activity is interpreted within the Ca^(2+)-dependent signaling network such that synaptic strength is eventually either potentiated or depressed. Many of the critical signaling enzymes that control synaptic plasticity, including Ca^(2+)/calmodulin-dependent protein kinase II (CaMKII), are regulated by calmodulin, a small protein that can bind up to 4 Ca^(2+) ions. As a first step toward clarifying how the Ca^(2+)-signaling network decides between potentiation or depression, we have created a kinetic model of the interactions of Ca^(2+), calmodulin, and CaMKII that represents our best understanding of the dynamics of these interactions under conditions that resemble those in a postsynaptic spine. We constrained parameters of the model from data in the literature, or from our own measurements, and then predicted time courses of activation and autophosphorylation of CaMKII under a variety of conditions. Simulations showed that species of calmodulin with fewer than four bound Ca^(2+) play a significant role in activation of CaMKII in the physiological regime, supporting the notion that processing ofCa^(2+) signals in a spine involves competition among target enzymes for binding to unsaturated species of CaM in an environment in which the concentration of Ca^(2+) is fluctuating rapidly. Indeed, we showed that dependence of activation on the frequency of Ca^(2+) transients arises from the kinetics of interaction of fluctuating Ca^(2+) with calmodulin/CaMKII complexes. We used parameter sensitivity analysis to identify which parameters will be most beneficial to measure more carefully to improve the accuracy of predictions. This model provides a quantitative base from which to build more complex dynamic models of postsynaptic signal transduction during learning

Potencial hidrogeniônico de antimicrobianos, segundo os fatores ambientais temperatura e luminosidade

The objective of this experimental study was to measure the pH of antibiotics administered by intravenous infusion - ceftriaxone sodium, vancomycin hydrochloride, metrodinazole, penicillin G potassium and amikacin sulfate - after reconstitution with sterile water and dilution with NaCl 0.9% or dextrose 5% in water, according to temperature and luminosity of the environment. The results showed that variation in the drugs' pH was less than 1.0 value and that some antibiotics remained acidic after dilution and maintained this chemical profile in all situations studied, suggesting that the studied environmental factors did not change the solutions' acid base characteristic. Some pH values measured characterize risk for the development of chemical phlebitis and infiltration, and it is important for clinical practice to emphasize the profile of intravenous solutions of antibiotics, considering method of dilution, and time to infusion.El objetivo de este estudio experimental fue medir el pH de los antibióticos de administración intravenosa ceftriaxona sódica, clorhidrato de vancomicina, metronidazol, penicilina G potásica y sulfato de amikacina, después de reconstitución con agua destilada y dilución con NaCl a 0,9%, o suero glucosado a 5%, considerando la influencia de la temperatura y luminosidad ambientales, así como el tiempo de exposición, en el comportamiento químico de esos fármacos. Los resultados demostraron variaciones que no ultrapasaron 1,0 (valor de pH) y que algunos antimicrobianos, eminentemente ácidos después de la dilución, mantuvieron ese comportamiento en todas las situaciones estudiadas, no sugiriendo la influencia de factores ambientales en el comportamiento químico de las soluciones. Considerando que algunos valores de pH encontrados pueden contribuir para el desarrollo de flebitis química e infiltración, es importante enfatizar que para la práctica clínica en salud, existe la necesidad de conocer las características de las soluciones de infusión intravenosa, considerando el tipo de dilución y el tiempo de infusión.O objetivo deste estudo experimental foi medir o pH dos antibióticos de administração intravenosa ceftriaxona sódica, cloridrato de vancomicina, metronidazol, penicilina G potássica e sulfato de amicacina, após reconstituição com água destilada e diluição com NaCl 0,9%, ou soro glicosado 5%, considerando a influência da temperatura e luminosidade ambientais, assim como do tempo de exposição, no comportamento químico desses fármacos. Os resultados demonstraram variações que não ultrapassaram 1,0 valor de pH e que alguns antimicrobianos, eminentemente ácidos após a diluição, mantiveram esse comportamento em todas as situações estudadas, não sugerindo a influência de fatores ambientais no comportamento químico das soluções. Como alguns valores de pH encontrados podem contribuir para o desenvolvimento de flebite química e infiltração, é importante enfatizar para a prática clínica em saúde, a necessidade de conhecer as características das soluções de infusão intravenosa, considerando tipo de diluição e tempo de infusão.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de São Paulo (UNIFESP) Departamento de EnfermagemUNIFESP, Depto. de EnfermagemCNPq: 476295/2004-1CNPq: 502382/2007-4SciEL