A Social Network Analysis of Occupational Segregation

We develop a social network model of occupational segregation between different social groups, generated by the existence of positive inbreeding bias among individuals from the same group. If network referrals are important for job search, then expected homophily in the contact network structure induces different career choices for individuals from different social groups. This further translates into stable occupational segregation equilibria in the labor market. We derive the conditions for wage and unemployment inequality in the segregation equilibria and characterize first and second best social welfare optima. Surprisingly, we find that socially optimal policies involve segregation.Social Networks, Homophily, Inbreeding Bias, Occupational Segregation, Labor Market Inequality, Social Welfare

Matching and Network Effects

This paper examines the existence and magnitude of network effects in the matching of workteams. We study the formation of co-author relations among economists over a thirty year period. Our principal finding is that a collaboration emerges faster among two authors if they are closer in the social network of economists. This proximity effect on collaboration is strong and robust but only affects initial collaboration. It has no positive influence on subsequent co-authorship. We also provide some evidence that matching depends on experience, junior authors being more likely to collaborate with senior authors.

Matching and Network Effects

This paper examines the existence and magnitude of network effects in the matching of work teams. We study the formation of co-author relations among economists over a thirty year period. Our principal finding is that a collaboration emerges faster among two authors if they are closer in the social network of economists. This proximity effect on collaboration is strong and robust but only affects initial collaboration. It has no positive influence on subsequent co-authorship. We also provide some evidence that matching depends on experience, junior authors being more likely to collaborate with senior authors

A Social Network Analysis of Occupational Segregation

We develop a network model of occupational segregation between social groups divided along gender or racial dimensions, generated by the existence of positive assortative matching among individuals from the same group. If referrals are important for job search, then expected homophily in the structure of job contact networks induces different career choices for individuals from different social groups. This further translates into stable occupational segregation equilibria in the labor market. We derive conditions for wage and unemployment inequality in the segregation equilibria and characterize both the first and the second best social welfare optima. We find that utilitarian socially optimal policies always involve segregation, but that integration policies are justifiable by additional distributional concerns. Our analysis suggests that social interaction through homophilous job referral networks is an important channel for the propagation and persistence of gender and racial inequalities in the labour market, complementary to classical theories such as taste or statistical discrimination

Social networks and research output

We study how knowledge about the social network of an individual researcher, as embodied in his coauthor relations, helps us in developing a more accurate prediction of his or her future productivity. We find that incorporating information about coauthor networks leads to a modest improvement in the accuracy of forecasts on individual output, over and above what we can predict based on the knowledge of past individual output. Second, we find that the informativeness of networks dissipates over the lifetime of a researcher’s career. This suggests that the signaling content of the network is quantitatively more important than the flow of ideas

Social networks and research output

We study how knowledge about the social network of an individual researcher - as embodied in his coauthor relations - helps us in developing a more accurate prediction of his future productivity. We find that incorporating information about coauthor networks leads to a modest improvement in the accuracy of forecasts on individual output, over and above what we can predict based on the knowledge of past individual output. Second, we find that the informativeness of networks dissipates over the lifetime of a researcher's career. This suggests that the signalling content of the network is quantitatively more important than the flow of ideas

Individual human serum differs in the amount of antibodies with affinity for pig fetal ventral mesencephalic cells and the ability to lyse these cells by complement activation

Xenografting pig fetal ventral mesencephalic (pfVM) cells to repair the dopamine deficit in patients with Parkinson's disease is the focus of both experimental and clinical investigations. Although there have been marked advances in the experimental and even clinical application of these xenogeneic transplantations, questions regarding the host's xenospecific immune response remain unanswered. It has been shown that human serum is able to lyse pfVM tissue by both anti-gal-gal and non-anti-gal-gal antibodies by complement activation. The aim of this study was to investigate whether interindividual differences exist in the levels of pfVM cell-specific IgM and IgG subclass antibodies, their ability to lyse pfVM cells in vitro and the relationship between both. Pig fetal VM cells were incubated with heat-inactivated serum from 10 different individuals and binding of IgM antibodies and IgG subclass antibodies to pfVM cells was analyzed by flow cytometry. The ability to lyse pfVM cells was analyzed exposing Cr-51-labeled pfVM cells to fresh serum or isolated IgM and IgG from the same individuals and subsequent determination of released Cr-51 from lysed cells. Strong differences were found between individuals in the levels of pfVM cell-specific IgM antibodies: antibody levels differed up to 40-fold. pfVM-specific IgG1 and IgG2 levels were only detectable in a few individuals. The ability to lyse pfVM cells ranged from negligible lysis up to 66.5% specific lysis. There was a strong correlation between the levels of individual pfVM-specific IgM antibodies and the ability to lyse pfVM cells in vitro. Isolated IgM, but not IgG, was able to lyse pfVM cells in the presence of complement. In conclusion, the interindividual differences in the levels of IgM with affinity for pfVM cells and their ability to lyse pfVM cells in vitro are considerable. Only few individuals possessed IgG1 and IgG2 subclass antibodies with affinity for pfVM. These findings may influence patient selection for porcine transplants and chances of graft survival in individual patients

Development of International Learning Outcomes for Shelter Medicine in Veterinary Education: A Delphi Approach

Shelter medicine is a veterinary discipline of growing importance. Formally accepted as a clinical specialty in the USA in 2014, the practice of shelter medicine worldwide is expanding. As a topic in veterinary pre-registration (undergraduate) education, it is frequently used as an opportunity to teach primary care skills, but increasingly recognized as a subject worthy of teaching in its own right. The aim of this study was to use a Delphi consensus methodology to identify learning outcomes relevant to shelter medicine education. Shelter medicine educators worldwide in a variety of settings, including universities, non-governmental organisations and shelters were invited to participate. Participants were initially invited to share shelter medicine teaching materials. These were synthesised and formatted into Learning Outcomes (LOs) based on Bloom’s taxonomy and organised into five subject-specific domains. Participants were then asked to develop and evaluate the identified LOs in two rounds of online surveys. Consensus was determined at >80% of panellists selecting “agree” or “strongly agree” in response to the statement “please indicate whether you would advise that it should be included in a shelter medicine education program” for each LO. In the second survey, where re-wording of accepted LOs was suggested, preference was determined at >50% agreement. Through this method, 102 agreed LOs have been identified and refined. These LOs, as well as those which did not reach consensus, are presented here. These are intended for use by shelter medicine educators worldwide, to enable and encourage the further development of this important veterinary discipline

Phase I study of intravenously applied bispecific antibody in renal cell cancer patients receiving subcutaneous interleukin 2.

In a phase I trial the toxicity and immunomodulatory effects of combined treatment with intravenous (i.v.) bispecific monoclonal antibody BIS-1 and subcutaneous (s.c.) interleukin 2 (IL-2) was studied in renal cell cancer patients. BIS-1 combines a specificity against CD3 on T lymphocytes with a specificity against a 40 kDa pancarcinoma-associated antigen, EGP-2. Patients received BIS-1 F(ab')2 fragments intravenously at doses of 1, 3 and 5 micrograms kg-1 body weight during a concomitantly given standard s.c. IL-2 treatment. For each dose, four patients were treated with a 2 h BIS-1 infusion in the second and fourth week of IL-2 therapy. Acute BIS-1 F(ab')2-related toxicity with symptoms of chills, peripheral vasoconstriction and temporary dyspnoea was observed in 2/4 and 5/5 patients at the 3 and 5 micrograms kg-1 dose level respectively. The maximum tolerated dose (MTD) of BIS-1 F(ab')2 was 5 micrograms kg-1. Elevated plasma levels of tumour necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma) were detected at the MTD. Flow cytometric analysis showed a dose-dependent binding of BIS-1 F(ab')2 to circulating T lymphocytes. Peripheral blood mononuclear cells (PBMCs), isolated after treatment with 3 and 5 micrograms kg-1 BIS-1, showed increased specific cytolytic capacity against EGP-2+ tumour cells as tested in an ex vivo performed assay. Maximal killing capacity of the PBMCs, as assessed by adding excess BIS-1 to the assay, was shown to be decreased after BIS-1 infusion at 5 micrograms kg-1 BIS-1 F(ab')2. A BIS-1 F(ab')2 dose-dependent disappearance of circulating mononuclear cells from the peripheral blood was observed. Within the circulating CD3+ CD8+ lymphocyte population. LFA-1 alpha-bright and HLA-DR+ T-cell numbers decreased preferentially. It is concluded that i.v. BIS-1 F(ab')2, when combined with s.c. IL-2, has a MTD of 5 micrograms kg-1. The treatment endows the T lymphocytes with a specific anti-EGP-2-directed cytotoxic potential