Indicazioni all\u2019uso delle protesi vascolari per l\u2019accesso emodialitico : un\u2019esperienza italiana basata sul consenso

In Italy, the use of arteriovenous grafts (AVGs) is limited (1-4%) due to different approaches to vascular access management compared to other countries, where guidelines that may not apply to the Italian setting have been produced. Therefore, the Vascular Access Study Group of the Italian Society of Nephrology produced this position paper, providing a list of 8 recommendations built upon current guidelines. The most controversial and innovative issues of the existing guidelines have been summed up in 12 different topics. We selected 60 Italian dialysis graft experts, nephrologists and vascular surgeons (PP1SIN Study Investigators). They were asked to express their approval or disapproval on each issue, thus creating a new method to share and exchange information. Almost all agreed on specific criteria for the choice of AVG over native arteriovenous fistulas (AVF) and tunneled venous catheters (tVC) and on the necessary conditions to implant them. They did not fully agree on the use of AVG in obese patients and patients at risk of developing ischemia, as an alternative to brachiobasilic fistula with vein transposition, and in case of a poorly organized setting. When AVF is feasible, it should be preferred. AVGs are indicated when superficial veins are unavailable or to repair an AVF (bridge graft). An AVG is an alternative to tVC if the expected patient survival is long enough to allow clinical benefits. The ultimate choice of the graft type is made by the physician in charge of the surgical intervention. Antithrombotic prophylaxis may be justified in some cases

A note on structural holes theory and niche overlap

Diffuse competition due to niche overlap between actors without (direct) ties with each other, constrains their structural autonomy. This is not dealt with in Burt’s mathematical model of his well-known structural holes theory. We fix his model by introducing a network measure of niche overlap

Knowledge growth through inter-organizational knowledge recombination: an analysis of the US semiconductor industry between 1976-2002

Si dà troppo spesso per scontato che le scelte e le soluzioni organizzative incidano profondamente sulle performance aziendali. Conseguentemente, i successi, le forze competitive emergenti, gli interventi efficaci sembrerebbero nascere e dipendere dalle capacità di innovare e di differenziare gli assetti organizzativi. I contributi raccolti in questo volume offrono una risposta meno scontata e più efficace, tracciando a partire dai diversi programmi e progetti di ricerca un percorso che tocca modalità, motivi, tempi e luoghi della differenza organizzativa. Diversi i temi che compongono questo mosaico di studi: il valore dell’organizzazione e le performance aziendali; le relazioni di lavoro e la gestione delle risorse umane; i modelli organizzativi dell’innovazione; le tecnologie di informazione e di comunicazione e gli assetti organizzativi; i fattori istituzionali, la cultura organizzativa e il management della diversità; le differenze organizzative nei settori economici, nelle relazioni interorganizzative e nel family business; le misure e la misurazione delle differenze negli studi organizzativi. Argomenti, tesi e conclusioni presentati e discussi sono un’occasione interessante di approfondimento sia per chi debba progettare, realizzare e gestire forme organizzative innovative, sia per chi voglia elaborare nuovi percorsi di ricerca e di studio

Knowledge specialization, knowledge brokerage, and the uneven growth of technology domains

Why do certain domains of knowledge grow fast while others grow slowly or stagnate? Two distinct theoretical arguments hold that knowledge growth is enhanced by knowledge specialization and knowledge brokerage. Based on the notion of recombinant knowledge growth, we show that specialization and brokerage are opposing modes of knowledge generation, the difference between them lying in the extent to which homogeneous vs. heterogeneous input ideas get creatively recombined. Accordingly, we investigate how both modes of knowledge generation can enhance the growth of technology domains. To address this question, we develop an argument that reconciles both specialization and brokerage into a dynamic explanation. Our contention is that specializing in an increasingly homogeneous set of input ideas is both more efficient and less risky than brokering knowledge. Nevertheless, specializing implies progressively exhausting available recombinant possibilities, while brokerage creates new ones. Hence, technology domains tend to grow faster when they specialize, but the more specialized they become, the more they need knowledge brokerage to grow. We cast out our argument into five hypotheses that predict how growth rates vary across technology domains

Social networks, cognitive style, and innovative performance: a contingency perspective

Integrating insights from cognitive psychology into current network theory on the social capital of brokering and closed networks, we argue that cognitive style is a critical contingency explaining the relation between social network position and innovative performance. Based on a “complementary fit” argument, we posit that a social network rich in structural holes enhances the innovative performance of employees with an adaptive cognitive style; however, individuals with an innovative cognitive style are most innovative when embedded within a closed network of densely interconnected contacts. Using data on the individual cognitive styles and complete workplace social networks of all employees within a design and manufacturing firm, we show that our theorized contingency mechanism accounts for a large share of empirical variation in employee innovative performance over and above existing social network explanations

Relational schemas to investigate the process of leadership emergence

Distancing itself from the traditional focus of leadership research on the behaviors and traits characteristic of “leaders,” the paper argues that leaders emerge out of a process of social construction. Drawing from relational schema theory, it is argued that group members form leadership perceptions that conform to a limited set of shared “hierarchical” relational schemas. Accordingly, whenever the leadership perceptions of an individual do not conform (i.e., they are hierarchically inconsistent) with those of other group members, he/she is induced to reduce such inconsistencies by aligning his/her own leadership perceptions. The paper tests this argument using a multi-method, multi-study approach. Study 1 follows the process of leadership emergence within a newly formed social group, showing how hierarchical relational schemas are reflected in the evolving network of leadership choices within the group. Study 2 uses a vignette experiment to directly test how hierarchical relational schemas affect people’s leadership perceptions