A Separable Model for Dynamic Networks

Models of dynamic networks --- networks that evolve over time --- have manifold applications. We develop a discrete-time generative model for social network evolution that inherits the richness and flexibility of the class of exponential-family random graph models. The model --- a Separable Temporal ERGM (STERGM) --- facilitates separable modeling of the tie duration distributions and the structural dynamics of tie formation. We develop likelihood-based inference for the model, and provide computational algorithms for maximum likelihood estimation. We illustrate the interpretability of the model in analyzing a longitudinal network of friendship ties within a school.Comment: 28 pages (including a 4-page appendix); a substantial rewrite, with many corrections, changes in terminology, and a different analysis for the exampl

Work, version, text and scriptum: high medieval manuscript terminology in the aftermath of the new philology

This article reviews the terminological framework to describe manuscripts. The Lachmannian terminology allows scholars to classify manuscripts as versions or variants of a work on a purely textual basis, but lacks a rigid designator to indicate a (part of a) manuscript as a unit of text and material considerations. Conversely, scholars who adopt Dagenais’ solution to renounce the work and concentrate on the material scriptum gain a rigid designator, but threaten to lose the ability to classify manuscripts at all. Proceeding from a case study, the article argues that the twelfth-century view of a work’s ontological status enables medievalists to keep classifying their scripta on both textual and material grounds. It explores the possibility of using Dagenais’ scriptum as the foundation for a Neo-Lachmannian terminological framework that allows scholars to study manuscript variance and materiality without losing the ability to classify them

Infants segment words from songs - an EEG study

Children’s songs are omnipresent and highly attractive stimuli in infants’ input. Previous work suggests that infants process linguistic–phonetic information from simplified sung melodies. The present study investigated whether infants learn words from ecologically valid children’s songs. Testing 40 Dutch-learning 10-month-olds in a familiarization-then-test electroencephalography (EEG) paradigm, this study asked whether infants can segment repeated target words embedded in songs during familiarization and subsequently recognize those words in continuous speech in the test phase. To replicate previous speech work and compare segmentation across modalities, infants participated in both song and speech sessions. Results showed a positive event-related potential (ERP) familiarity effect to the final compared to the first target occurrences during both song and speech familiarization. No evidence was found for word recognition in the test phase following either song or speech. Comparisons across the stimuli of the present and a comparable previous study suggested that acoustic prominence and speech rate may have contributed to the polarity of the ERP familiarity effect and its absence in the test phase. Overall, the present study provides evidence that 10-month-old infants can segment words embedded in songs, and it raises questions about the acoustic and other factors that enable or hinder infant word segmentation from songs and speech

Entrepreneurship in the Netherlands: Ambitious entrepreneurs: the driving force for the next millennium

Studie naar de dynamiek van jonge bedrijven en snelgroeiende bedrijven in Nederland, Denemarken, het Verenigd Koninkrijk, de Verenigde Staten en Zweden. In Nederland zijn er relatief weinig bedrijven met hoge werkgelegenheidsgroei. In tegenstelling tot andere landen ontwikkelt de Nederlandse overheid wel beleid om snelgroeiende bedrijven te ondersteunen.

Who students interact with? A social network analysis perspective on the use of Twitter in language learning

This paper reports student interaction patterns and self-reported results of using Twitter microblogging environment. The study employs longitudinal probabilistic social network analysis (SNA) to identify the patterns and trends of network dynamics. It is building on earlier works that explore associations of student achievement records with the observed network measures. It integrates gender as an additional variable and reports some relation with interaction patterns. Additionally, the paper reports the results of a questionnaire that enables further discussion on the communication patterns

Entrepreneurship in the Netherlands: Opportunities and threats to nascent entrepreneurship

Derde editie van ‘Entrepreneurship in the Netherlands’. In drie bijdragen wordt ingegaan op de fase voor de start van een nieuw bedrijf. De rol van prestarters in de Nederlandse economie wordt beschreven. Het stimuleringsbeleid ten aanzien van prestarters komt aan de orde, met bijzondere aandacht voor de stimulering van ondernemerschap in het onderwijs. Tot slot wordt een vergelijking gemaakt tussen de ontwikkeling van prestarters in de Verenigde Staten en die in Nederland. De verschillen tussen Nederland en de VS worden uitgelegd in de context van verschillen tussen de nationale, culturele, politieke en economische systemen in de twee landen.

Water Masers Associated with Star Formation in the Antennae Galaxies

We present Very Large Array observations with 80 milliarcsecond resolution (~9 pc) of the recently discovered Galactic-analog water masers in the Antennae interacting galaxies (NGC 4038/NGC 4039; Arp244). Three regions of water maser emission are detected: two in the ``interaction region'' (IAR) and the third ~5.6'' (> 600 pc) west of the NGC 4039 nucleus. The isotropic water maser luminosities range from 1.3 to 7.7 L_sun. All three maser regions are mostly obscured in the optical/near-infrared continuum, and are coincident with massive CO-identified molecular clouds. The water maser velocities are in excellent agreement with those of the molecular gas. We also present archival VLA 3.6 cm data with ~0.28" (~30 pc) and ~0.8" (~90 pc) resolution toward the maser locations. All three maser regions are coincident with compact 3.6 cm radio continuum emission, and two are dominated by thermal ionized gas, suggesting the presence of natal super star clusters containing the equivalent of a few thousand O stars. We also present detailed comparisons between the radio data and existing HST ACS (optical) and NICMOS (near-IR) data and find that both maser regions in the IAR are also associated with Pa\alpha emission and neither source is detected shortward of 2 microns. These results highlight the potential of using Galactic-analog water masers to pinpoint sites of young super star cluster formation with exquisite angular resolution.Comment: Accepted to ApJ Letters: 14 pages, 2 figure

The use of maxLength in the RPKI

This document recommends that operators avoid using the maxLength attribute when issuing Route Origin Authorizations (ROAs) in the Resource Public Key Infrastructure (RPKI). These recommendations complement those in [RFC7115].https://datatracker.ietf.org/doc/draft-yossigi-rpkimaxlen/First author draf