Transparency in repeated procurement. When hiding is better

In this paper we study the effect of transparency on the willingness to collude in repeated procurement competitive tenderings. We allow the buyer to postpone the revelation of the winner's identity and show that such a policy may make collusive agreements less stable in both simultaneous and sequential competitive procedures. When the buyer postpones the revelation of the winner's identity in a scenario in which colluding and "honest" (never colluding) firms participate to the same tendering, the threat of a retaliation, by means of an aggressive bidding by the colluding firms, is weakened and collusion is less stable

Scanning-helium-ion-beam lithography with hydrogen silsesquioxane resist

A scanning-helium-ion-beam microscope is now commercially available. This microscope can be used to perform lithography similar to, but of potentially higher resolution than, scanning electron-beam lithography. This article describes the control of this microscope for lithography via beam steering/blanking electronics and evaluates the high-resolution performance of scanning helium-ion-beam lithography. The authors found that sub-10 nm-half-pitch patterning is feasible. They also measured a point-spread function that indicates a reduction in the micrometer-range proximity effect typical in electron-beam lithography.National Science Foundation (U.S.). Graduate Research Fellowship Progra

Impact of age norms and stereotypes on managers' hiring decisions of retirees

Purpose -Our study investigates the role of managers in the re-employment of early retirees and asks what the effect is of managers’ age norms and stereotypes on managers’ employment decisions. Design/methodology/approach- A combination of a factorial study and a survey was conducted. First, information on the age norms and stereotypes was collected. Secondly, profiles of hypothetical retired job applicants were presented to the employers, who were asked to make a specific hiring decision. The information collected during both studies was combined in the analysis and multilevel models were estimated. Findings -The results indicate that higher age norms result in a higher propensity to hire an early retiree. Stereotypes, by contrast, do not influence managers’ decisions. Early retirees’ chances for re-employment are also related to their own circumstances (physical appearance and relevant experience) and organisational forces, as they are hired when organisations face labour force shortages. Research limitation / implications – with the use of vignettes study we deal with hypothetical hiring situation. Originality value- Although the effect of age norms and age stereotypes has been often suggested, not much empirical evidence was presented to support this notion. Our study estimates the effect of age norms and stereotypes on hiring decision. key words: bridge employment; early retirees; age norms; age stereotypes; multilevel models.

Inflammatory myoglandular polyp of the cecum: case report and review of literature

<p>Abstract</p> <p>Background</p> <p>Inflammatory myoglandular polyp (IMGP) is a rare non-neoplastic polyp of the large bowel, commonly with a distal localization (rectosigmoid), obscure in its pathogenesis. Up till now, 60 cases of IMGP have been described in the literature, but none located in the cecum.</p> <p>Case presentation</p> <p>We report a case of a 53-year-old man who was admitted to our hospital for further evaluation of positive fecal occult blood test associated to anemia. A colonoscopy identified a red, sessile, lobulated polyp of the cecum, 4.2 cm in diameter, partially ulcerated. The histological examination of the biopsy revealed the presence of inflammatory granulation tissue with lymphocytic and eosinophil infiltration associated to a fibrous stroma: it was diagnosed as inflammatory fibroid polyp. Considering the polyp's features (absence of a peduncle and size) that could increase the risk of a polypectomy, a surgical resection was performed. Histological examination of the specimen revealed inflammatory granulation tissue in the lamina propria, hyperplastic glands with cystic dilatations, proliferation of smooth muscle and multiple erosions on the polyp surface: this polyp was finally diagnosed as IMGP. There was also another little polyp next to the ileocecal valve, not revealed at the colonoscopy, 0.8 cm in diameter, diagnosed as tubulovillous adenoma with low grade dysplasia.</p> <p>Conclusions</p> <p>This is the first case of IMGP of the cecum. It is a benign lesion of unknown pathogenesis and must be considered different from other non-neoplastic polyps of the large bowel such as inflammatory cap polyps (ICP), inflammatory cloacogenic polyps, juvenile polyps (JP), inflammatory fibroid polyps (IFP), polyps secondary to mucosal prolapse syndrome (MPS), polypoid prolapsing mucosal folds of diverticular disease. When symptomatic, IMGP should be removed endoscopically, whereas surgical resection is reserved only in selected patients as in our case.</p

Appendectomy during the COVID-19 pandemic in Italy: a multicenter ambispective cohort study by the Italian Society of Endoscopic Surgery and new technologies (the CRAC study)

Major surgical societies advised using non-operative management of appendicitis and suggested against laparoscopy during the COVID-19 pandemic. The hypothesis is that a significant reduction in the number of emergent appendectomies was observed during the pandemic, restricted to complex cases. The study aimed to analyse emergent surgical appendectomies during pandemic on a national basis and compare it to the same period of the previous year. This is a multicentre, retrospective, observational study investigating the outcomes of patients undergoing emergent appendectomy in March-April 2019 vs March-April 2020. The primary outcome was the number of appendectomies performed, classified according to the American Association for the Surgery of Trauma (AAST) score. Secondary outcomes were the type of surgical technique employed (laparoscopic vs open) and the complication rates. One thousand five hundred forty one patients with acute appendicitis underwent surgery during the two study periods. 1337 (86.8%) patients met the inclusion criteria: 546 (40.8%) patients underwent surgery for acute appendicitis in 2020 and 791 (59.2%) in 2019. According to AAST, patients with complicated appendicitis operated in 2019 were 30.3% vs 39.9% in 2020 (p = 0.001). We observed an increase in the number of post-operative complications in 2020 (15.9%) compared to 2019 (9.6%) (p &lt; 0.001). The following determinants increased the likelihood of complication occurrence: undergoing surgery during 2020 (+ 67%), the increase of a unit in the AAST score (+ 26%), surgery performed &gt; 24 h after admission (+ 58%), open surgery (+ 112%) and conversion to open surgery (+ 166%). In Italian hospitals, in March and April 2020, the number of appendectomies has drastically dropped. During the first pandemic wave, patients undergoing surgery were more frequently affected by more severe appendicitis than the previous year's timeframe and experienced a higher number of complications. Trial registration number and date: Research Registry ID 5789, May 7th, 202

Tracking Cancer Evolution Reveals Constrained Routes to Metastases: TRACERx Renal.

Clear-cell renal cell carcinoma (ccRCC) exhibits a broad range of metastatic phenotypes that have not been systematically studied to date. Here, we analyzed 575 primary and 335 metastatic biopsies across 100 patients with metastatic ccRCC, including two cases sampledat post-mortem. Metastatic competence was afforded by chromosome complexity, and we identify 9p loss as a highly selected event driving metastasis and ccRCC-related mortality (p = 0.0014). Distinct patterns of metastatic dissemination were observed, including rapid progression to multiple tissue sites seeded by primary tumors of monoclonal structure. By contrast, we observed attenuated progression in cases characterized by high primary tumor heterogeneity, with metastatic competence acquired gradually and initial progression to solitary metastasis. Finally, we observed early divergence of primitive ancestral clones and protracted latency of up to two decades as a feature of pancreatic metastases

Pre clinical development of Trans sialidase based prophylactic vaccines against Chagas disease

La Enfermedad de Chagas (ECh), ocasionada por el parásito flagelado Trypanosoma cruzi (T. cruzi), es una de las parasitosis de mayor impacto en la Salud Pública de Latinoamérica. Si bien actualmente existen medidas de prevención como el tamizaje en bancos de sangre, el control a las embarazadas y el control vectorial, aún se requiere de estrategias más eficaces para evitar nuevos casos. Una de estas posibles estrategias es el desarrollo de una vacuna profiláctica contra T. cruzi. Desde el descubrimiento de la enfermedad en 1909, se han evaluado diferentes vacunas experimentales, pero aún no se ha logrado el desarrollo clínico de una formulación efectiva contra el parásito. En este artículo realizamos una revisión bibliográfica acerca de las distintas estrategias de vacunación que se evaluaron hasta la actualidad y, particularmente, el uso de la enzima Transialidasa (TS) como antígeno vacunal. También abordamos distintos aspectos de la superfamilia de la TS, como la clasificación de las distintas proteínas, sus características funcionales y su rol en la infección por T. cruzi. A lo largo de 100 años se han abordado y perfeccionado una gran diversidad de estrategias vacunales contra T. cruzi, lo cual permite augurar el salto desde el campo pre—clínico al desarrollo clínico de una vacuna efectiva en un futuro cercano.Chagas disease (ChD) is caused by the flagellated parasite Trypanosoma cruzi (T. cruzi), representing a serious public health in Latin America. Currently, there are prevention measures such as blood screening, control of pregnant women and vector control, but more effective strategies are still required to prevent new cases. One of these strategies is the development of a prophylactic vaccine against T. cruzi. Since the discovery of the disease in 1909, different experimental vaccines have been evaluated, but the clinical development of an effective formulation against the parasite has not yet been achieved. Here, we review the different vaccination strategies that have been evaluated to date, and particularly, the use of the enzyme Trans—sialidase (TS) as a vaccine antigen. We also address different aspects of the TS superfamily, such as the classification of the different proteins, their functional characteristics, and their role in T. cruzi infection. Over 100 years, a great diversity of vaccine strategies against T. cruzi have been approached and refined, auguring that in the near future it will be possible to cross from the pre—clinical to the clinical field