Differential cross section for Aharonov--Bohm effect with non standard boundary conditions

A basic analysis is provided for the differential cross section characterizing Aharonov--Bohm effect with non standard (non regular) boundary conditions imposed on a wave function at the potential barrier. If compared with the standard case two new features can occur: a violation of rotational symmetry and a more significant backward scattering.Comment: to appear in Europhys. Let

Cashback is cash forward: delaying a discount to entice future spending

The authors examine purchase behavior in the context of cashback shopping—a novel form of price promotion online where consumers initiate transactions at the website of a cashback company and, after a significant delay, receive the savings promised to them. Specifically, they analyze panel data from a large cashback company and show that, independent of the predictable effect of cashback offers on initial demand, cashback payments (1) increase the probability that consumers make an additional purchase via the website of the cashback company, and (2) increase the size of that purchase. These effects pass several robustness checks. They are also meaningful: at the average values in the data an additional $1.00 in cashback payment increases the likelihood of a future transaction by 0.02$0.32—figures that represent 10.03% of the overall impact of a given promotion. Moreover, the authors find that consumers are more likely to spend the money returned to them at generalists such as department stores than at other retailers. They consider three explanations for these findings, and the leading hypothesis is that consumers fail to treat money as a fungible resource. They also discuss implications for cashback companies and retailers

The effect of individual online reviews on purchase likelihood

Online product reviews constitute a powerful source of information for consumers. Past research has studied the effect of aggregate measures of reviews (such as, average product rating and number of reviews) on consumer behaviour. In this study, we investigate how individual reviews displayed on a product webpage affect consumers’ purchase likelihood. Identifying this effect is challenging because retailers are free to select which reviews to display on the product page and in what order, making the display of reviews in particular positions potentially endogenous. We address this challenge by utilizing an empirical context where the retailer displays reviews by recency and exploit the variation in review positions generated as newer reviews are added on top of older ones. We find that individual reviews have a strong effect on consumer purchase decisions. These effects are particularly pronounced when individual reviews help consumers resolve uncertainty about the product or contrast with the aggregate information that is instantly available on the product page

Rejeição e efeitos da ciclosporina nos transplantes cutâneos alógenos microcirúrgicos em ratos

Os efeitos da rejeição e da imunossupressão com ciclosporina A em retalhos epigástricos utilizados como transplantes cutâneos alógenos microcirúrgicos, foram estudados em 58 ratos, distribuídos em três grupos: Wistar-Furth isogênicos doadores e receptores; e Brown-Norway doadores e Wistar-Furth receptores, imunossuprimidos com cicloporina A(10mg/kg/dia). Biópsias dos retalhos e da pele normal contralateral utilizadas como contrôle foram colhidas no terceiro, sétimo, 15º e 30º dias pós transplante. As biópsias foram preparadas em historesina, e coradas em azul de toluidina, para avaliação do infiltrado inflamatório local, permitindo estudo quantitativo dos linfócitos infiltrantes nos retalhos. O modelo revelou-se eficiente, obtendo-se sobrevivência dos transplantes por 30 dias, de 83,3% entre animais isogênicos, e de 60% nos alogênicos sob ação da ciclosporina A. Em ratos alogênicos não imunossuprimidos houve 100% de rejeição dos retalhos, até o nono dia pós-operatório. Nos transplantes desses animais, verificou-se aumento significativo do número de linfócitos infiltrantes no terceiro dia, quando comparados aos ratos isogênicos. A linfocitose observada antecedeu os achados macroscópicos da rejeição, verificados apenas no quinto ou sexto dias.The rejection of allotransplantation of epigastric microsurgical flaps and the effect of immunosuppression have been studied in 58 rats. Three sets of experiments were planned: (1) Wistar Furth isogenic donors and receptors (control set); (2) Brown Norway donors and Wistar Furth receptors (rejection set); and (3) Brown Norway donors and Wistar Furth immunosuppressed receptors (cyclosporin A set). Cyclosporin A (10 mg/kg/d) treated rats had a transplantation survival rate of up to 30 days: 83.3% among isogenic animals and 60% among allogeneic. There was 100% rejection by the 9th day after the transplantation in allogeneic non-immunosuppressed rats. Biopsies embedded with historesin were taken from the flap and normal contralateral skin (used as control) on the 3rd, 7th, 15th, and 30th days after the surgery. A quantitative study of infiltrating lymphocytes in the flaps, with and without cyclosporin A, was done by evaluating the local inflammatory infiltrate. A significant increase in the number of lymphocytes among the rejection and immunosuppressed groups was seen, as compared to the isogenic set. Local lymphocytosis in allogeneic non-immunosuppressed transplantations reached its highest level on the 3rd day after surgery, before gross findings of rejection, which could only be seen by naked eye on the 5th or 6th day. Therefore, we conclude that cyclosporin A is effective in preserving allogenic transplantation in rats. Biopsies of transplanted areas may contribute to earlier diagnosis of the need for immunosuppressive therapy

Public perceptions and expectations: disentangling the hope and hype of organoid research

Organoid technologies are rapidly advancing and hold great potential and hope for disease modeling and clinical translational research. Still, they raise a number of complex, ethical questions regarding their current and future use. Patient and public involvement is impor-tant in building public trust and helping to secure responsible conduct and valued innovations; nevertheless, research into patient and public perspectives on organoid technologies remains scarce. We report on a first public dialogue on organoid technologies through three cross-country deliberative workshops with a diverse group of stakeholders to identify their perceptions and concerns. Participants gener-ally support organoid technologies on the condition that responsible governance, ethical oversight, and sound informed consent procedures are in place. Yet, a broad set of potential concerns are identified, primarily concerning commercialization, healthcare access, and cerebral organoids. Participants' insights and recommendations can help inform researchers and ethics and policy bodies toward supporting responsible and ethical organoid approaches

Recurrent Retrorectal Teratoma

Retrorectal tumors are a rare group of neoplasms that occur most commonly in the neonatal and infant population. They vary in presentation, but teratomas are the most common and often present as a protruding mass from the sacrococcygeal region. Immediate surgical resection is indicated when found and coccygectomy is performed to prevent recurrence. When teratomas recur, the patients most often have vague symptoms and the tumors usually have malignant transformation. Here, we present the case of a young woman who underwent surgical resection of a sacrococcygeal teratoma at 3 days of age where the coccyx was not removed. She presented at 31 years of age with lower extremity paresthesias and radiography revealed a cystic mass extending from the sacrum. After resection, pathology revealed a recurrent teratoma with nests of adenocarcinoma

Formation and characteristics of ions and charged aerosol particles in a native Australian Eucalypt forest

International audienceBiogenic aerosol formation is likely to contribute significantly to the global aerosol load. In recent years, new-particle formation has been observed in various ecosystems around the world but hardly any measurements have taken place in the terrestrial Southern Hemisphere. Here, we report the first results of atmospheric ion and charged particle concentrations as well as of new-particle formation in a Eucalypt forest in Tumbarumba, South-East Australia, from July 2005 to October 2006. The measurements were carried out with an Air Ion Spectrometer (AIS) with a size range from 0.34 to 40 nm. The Eucalypt forest was a very strong source of new aerosol particles. Daytime aerosol formation took place on 52% of days with acceptable data, which is 2?3 times as often as in the Nordic boreal zone. Average growth rates for negative/positive 1.5?3 nm particles during these formation events were 2.89/2.68 nmh?1, respectively; for 3-7 nm particles 4.26/4.03, and for 7?20 nm particles 8.90/7.58 nmh?1, respectively. The growth rates for large ions were highest when the air was coming from the native forest which suggests that the Eucalypts were a strong source of condensable vapours. Average concentrations of cluster ions (0.34?1.8 nm) were 2400/1700 cm?3 for negative/positive ions, very high compared to most other measurements around the world. One reason behind these high concentrations could be the strong radon efflux from the soils around the Tumbarumba field site. Furthermore, comparison between night-time and daytime concentrations supported the view that cluster ions are produced close to the surface within the boundary layer also at night but that large ions are mostly produced in daytime. Finally, a previously unreported phenomenon, nocturnal aerosol formation, appeared in 32% of the analysed nights but was clustered almost entirely within six months from summer to autumn in 2006. From January to May, nocturnal formation was 2.5 times as frequent as daytime formation. Therefore, it appears that in summer and autumn, nocturnal production was the major mechanism for aerosol formation in Tumbarumba