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SIENA (for Simulation Investigation for Empirical Network Analysis) is a computer program that carries out the statistical estimation of models for the evolution of social networks according to the dynamic actor-oriented model of Snijders (2001, 2003) and Steglich, Snijders and Pear-son (2004). It also carries out MCMC estimation for the exponential random(More)
The collection of longitudinal data on complete social networks often faces the problem of actor non-response. The resulting incomplete data pose a challenge to statistical analysis, as there typically is no natural way to treat the missing cases. This paper examines the problems caused by actors missing as nominators, but still occurring as nominees, in(More)
This sparkling Handbook offers an unrivalled resource. Systematically, it introduces readers to the key concepts, substantive topics, central methods and prime debates. · 712 pages eade s to t e ey co cepts, substa t e top cs, ce t a et ods a d p e debates Among the specific areas covered are: • Network theory • Interdisciplinary applications • Online(More)
In this paper we both describe and analyze the meeting process and the evolution of a friendship network among sociology freshmen in the Netherlands. We develop a theory that explains how changes in the network structure depend on one or more of four main effects: proximity, visible similarity, invisible similarity, and network opportunity. We formulate(More)
OBJECTIVE To investigate the association between cigarette smoking, level of education, occupation, and the occurrence of sporadic amyotrophic lateral sclerosis (ALS). METHODS A total of 364 patients and 392 controls completed a questionnaire covering smoking habits, level of education, and occupational history. Main occupations were coded according to(More)
BACKGROUND Variation in the incidence rate in epidemiological studies on amyotrophic lateral sclerosis (ALS) may be due to a small population size and under ascertainment of patients. The previously reported incidence decline in the elderly and a decrease in the male:female ratio in postmenopausal age groups have yet to be confirmed. METHODS ALS(More)
OBJECTIVE To assess the frequency and phenotype of hexanucleotide repeat expansions in C9ORF72 in a large cohort of patients of Dutch descent with familial (fALS) and sporadic (sALS) amyotrophic lateral sclerosis (ALS), progressive muscular atrophy (PMA), and primary lateral sclerosis (PLS). METHODS Included were 78 patients with fALS, 1,422 with sALS,(More)
Analysis of social network data is often hampered by non-response and missing data. Recent studies show the negative effects of missing actors and ties on the structural properties of social networks. This means that the results of social network analyses can be severely biased if missing ties were ignored and only complete cases were analyzed. To overcome(More)
OBJECTIVE To determine whether the frequency of Parkinson disease (PD), dementia, and vascular diseases in relatives of patients with amyotrophic lateral sclerosis (ALS) differs from the frequency of those diseases in relatives of controls, providing further information about the association between these diseases. METHODS We studied the occurrence of(More)