PRDM14 is expressed in germ cell tumors with constitutive overexpression altering human germline differentiation and proliferation.

Germ cell tumors (GCTs) are a heterogeneous group of tumors occurring in gonadal and extragonadal locations. GCTs are hypothesized to arise from primordial germ cells (PGCs), which fail to differentiate. One recently identified susceptibility loci for human GCT is PR (PRDI-BF1 and RIZ) domain proteins 14 (PRDM14). PRDM14 is expressed in early primate PGCs and is repressed as PGCs differentiate. To examine PRDM14 in human GCTs we profiled human GCT cell lines and patient samples and discovered that PRDM14 is expressed in embryonal carcinoma cell lines, embryonal carcinomas, seminomas, intracranial germinomas and yolk sac tumors, but is not expressed in teratomas. To model constitutive overexpression in human PGCs, we generated PGC-like cells (PGCLCs) from human pluripotent stem cells (PSCs) and discovered that elevated expression of PRDM14 does not block early PGC formation. Instead, we show that elevated PRDM14 in PGCLCs causes proliferation and differentiation defects in the germline

Interstate Differences in Employer Tax Costs and Worker Benefits of Unemployment Insurance: A Micro-Simulation Approach

This study compares employer unemployment insurance (UI) tax costs and worker UI benefits across the 28 largest industrial states for 1988. The comparison is done using a detailed computerized micro-simulation model which computes the worker UI benefits and employer UI taxes for each state. Assumed characteristics of employers and employees are held constant across the states so that differences in UI costs and benefits among the states can be attributed entirely to differences in UI statutes. The principal findings of this study are: (1) the UI system can be modeled fruitfully at the firm level, (2) there are significant UI tax differentials across states attributable to statutory provisions, (3) UI tax differentials vary by type of employer, and (4) there is at least one significant regional difference: UI taxes are generally lower in Southern states

A model-based approach to the tempo of “collapse”: The case of Rapa Nui (Easter Island)

Rapa Nui (Easter Island, Chile) presents a quintessential case where the tempo of investment in monumentality is central to debates regarding societal collapse, with the common narrative positing that statue platform (ahu) construction ceased sometime around AD 1600 following an ecological, cultural, and demographic catastrophe. This narrative remains especially popular in fields outside archaeology that treat collapse as historical fact and use Rapa Nui as a model for collapse more generally. Resolving the tempo of “collapse” events, however, is often fraught with ambiguity given a lack of formal modeling, uncritical use of radiocarbon estimates, and inattention to information embedded in stratigraphic features. Here, we use a Bayesian model-based approach to examine the tempo of events associated with arguments about collapse on Rapa Nui. We integrate radiocarbon dates, relative architectural stratigraphy, and ethnohistoric accounts to quantify the onset, rate, and end of monument construction as a means of testing the collapse hypothesis. We demonstrate that ahu construction began soon after colonization and increased rapidly, sometime between the early-14th and mid-15th centuries AD, with a steady rate of construction events that continued beyond European contact in 1722. Our results demonstrate a lack of evidence for a pre-contact ‘collapse’ and instead offer strong support for a new emerging model of resilient communities that continued their long-term traditions despite the impacts of European arrival. Meth- odologically, our model-based approach to testing hypotheses regarding the chronology of collapse can be extended to other case studies around the world where similar debates remain difficult to resolve