Rigorous Bounds on the Free Energy of Electron-Phonon Models

We present a collection of rigorous upper and lower bounds to the free energy of electron-phonon models with linear electron-phonon interaction. These bounds are used to compare different variational approaches. It is shown rigorously that the ground states corresponding to the sharpest bounds do not exhibit Off-Diagonal Long-Range Order in the two-particle density matrix.

Price Discrimination Bans on Dominant Firms

Competition authorities and regulatory agencies sometimes impose pricing restrictions on firms with substantial market power — the “dominant” firms. We analyze the welfare effects of a ban on behaviour-based price discrimination in a two-period setting where the market displays a competitive and a sheltered segment. A ban on “higher-prices-to-sheltered-consumers” decreases prices in the sheltered segment, relaxes competition in the competitive segment, increases the rival’s profits, and may harm the dominant firm’s profits. We show that a ban on “higher-prices-to-sheltered-consumers” increases the dominant firm’s share of the first-period market. A ban on “lower-prices-to-rival’s-customers” decreases prices in the competitive segment, lowers the rival’s profits, and augments the consumer surplus. In particular, while second-period competition is relaxed by a ban on “lower-prices-to-rival’s-customers”, first-period competition is intensified substantially, which leads to lower prices “on-average” over the two periods. Our findings indicate that a dynamic two-period analysis may lead to conclusions opposite to those drawn from a static one-period analysis.dominant firms, price discrimination, competition policy, regulation

Bertrand competition with an asymmetric no-discrimination constraint.

We study the competitive and welfare consequences when only one firm must commit to uniform pricing while the competitor's pricing policy is left unconstrained. The asymmetric no-discrimination constraint prohibits both behaviour-based price discrimination within the competitive segment and third-degree price discrimination across the monopolistic and competitive segments. We find that an asymmetric no-discrimination constraint only leads to higher profits for the unconstrained firm if the monopolistic segment is large enough. Therefore, a regulatory policy objective of encouraging entry is not served by an asymmetric no-discrimination constraint if the monopolitic segment is small. Only when the monopolistic segment is small and rivalry exists in the competitive segment does the asymmetric no-discrimination constraint enhance welfare.

Comfortably numb?:Researchers’ satisfaction with the publication system and a proposal for radical change

In this preregistered study we evaluate current attitudes towards, and experiences with, publishing research and propose an alternative system of publishing. Our main hypothesis is that researchers tend to become institutionalized, such that they are generally discontent with the current publication system, but that this dissatisfaction fades over time as they become tenured. A survey was distributed to the first authors of papers published in four recent issues of top-15 Work and Organizational Psychology (WOP) journals. Even among this positively biased sample, we found that the time it takes to publish a manuscript is negatively associated with whether authors perceive this time to be justifiable and worthwhile relative to the amount their manuscript has changed. Review quality and tenure buffer the negative relationship with perceived justifiability, but not for perceived worth. The findings suggest that untenured (WOP) researchers are dissatisfied with the publishing times of academic journals, which adds to the pile of criticisms of the journal-based publication system. Since publishing times are inherent to the journal-based publication system, we suggest that incremental improvements may not sufficiently address the problems associated with publishing times. We therefore propose the adoption of a modular publication system to improve (WOP) publishing experiences

INIBIZIONE DELL' ALDOSO REDUTTASI DA EMIACETALI

L'aldoso reduttasi (alditol:NADP oxidoreductase, EC 1.1.1.21) (AR) è un enzima citosolico monomerico, appartenente alla famiglia delle aldo-cheto reduttasi, in grado di agire su aldeidi sia aromatiche che alifatiche. Esso catalizza la prima tappa (che è anche quella limitante) della via dei polioli, che consiste nella riduzione NADPH-dipendente del glucosio in sorbitolo. La seconda tappa della suddetta via, catalizzata dalla sorbitolo deidrogenasi, converte il sorbitolo in fruttosio, in una reazione NAD+-dipendente. In condizioni fisiologiche, la via dei polioli coinvolge meno del 3% del glucosio totale presente nella cellula, poiché la quasi totalità dello zucchero viene fosforilato dalla esochinasi, che lo convoglia nella via glicolitica. In condizioni di iperglicemia, come nel caso dei soggetti diabetici, una quota di di glucosio diventa substrato dell'aldoso reduttasi e il flusso di glucosio attraverso la via dei polioli può interessare percentuali fino al 30%. del glucosio totale L’aumento di flusso attraverso la via dei polioli è considerato dannoso per una serie di ragioni: la prima riguarda l'accumulo di sorbitolo all'interno della cellula, che causa uno squilibrio osmotico tale da richiamare acqua dall'esterno, con gravi alterazioni del normale equilibrio elettrolitico. La seconda riguarda l’aumento della produzione di fruttosio che , essendo un agente glicante addirittura migliore del glucosio stesso, può indurre fenomeni di glicazione proteica. Infine, l’aumento del consumo di NADPH ad opera dell’AR determina una riduzione delle difese antiossidanti della cellula. Queste alterazioni metaboliche correlate con l’aumentato flusso attraverso la via dei polioli sono considerate responsabili dell’insorgenza delle cosiddette complicanze diabetiche, che includono cataratta, neuropatie, nefropatie e retinopatie. Per questo l’AR è da tempo considerata un bersaglio per l’identificazione di inibitori che possano portare allo sviluppo di farmaci contro le complicanze del diabete. Sebbene il glucosio rappresenti uno dei substrati di AR più rilevanti dal punto di vista fisiopatologico, la reazione di riduzione catalizzata dall’enzima mostra ancora alcuni aspetti non completamente chiariti. Tra questi, l’apparente cooperatività negativa che è stata osservata con questo substrato e che è stata ascritta all’esistenza di più forme enzimatiche. Il lavoro sperimentale riportato in questa tesi ha fatto uso sia di AR ricombinante umana. I risultati ottenuti indicano che le strutture emiacetaliche degli aldosi esercitano un effetto modulatorio sulla riduzione della forma aldeidica libera catalizzata dall’AR e che questo effetto è in grado di dare spiegazione dell’apparente negatività cooperativa osservata per l’enzima

Post-menopausal vaginal bleeding caused by carcinoma of the appendix: a case report

<p>Abstract</p> <p>Introduction</p> <p>Post-menopausal blood loss is a common complaint of patients seen in gynecological practice. The most frequent malignancy found in cases of post-menopausal bleeding is endometrial cancer. Other causes can be malignancies of the rest of a woman's genital tract or metastases from other tumors. To the best of our knowledge, it appears that this is the first published case of a post-menopausal primary appendiceal carcinoma presenting with vaginal blood loss.</p> <p>Case presentation</p> <p>A 75-year-old Caucasian woman with a history of vaginal hysterectomy presented with a 10-month history of post-menopausal blood loss. After extensive examination and discussion, ovarian carcinoma was suggested. Microscopic examination of the tissue removed at laparotomy revealed an adenocarcinoma of the appendix. She was treated with adjuvant radiotherapy and with palliative chemotherapy after 14 months because of intra-abdominal metastatic disease.</p> <p>Conclusion</p> <p>Post-menopausal blood loss in a patient with a history of hysterectomy is uncommon and always needs further investigation.</p