of 150 to 200 km. Our discontinuity depths lie at
the intersection of the conductive geotherm and
the carbonate-silicate solidus (Fig. 4), where the
mantle is likely metasomatized (6, 37). The presence of metasomatism and enrichment in volatiles
would cause the mantle to be partially melted at
If small degrees of carbonated silicate melts are
present today beneath the continents, this could
explain the seismic discontinuity at 130 to 190 km
and also define the base of the continental lithosphere. Melt has a strong effect on shear velocity,
with 1% partial melt reducing velocity by 7.9% (38),
consistent with our observations. The presence of
partial melt would also enhance mantle deformation, effectively lowering mantle viscosity (39, 40).
The reduced viscosity would likely enhance convection, raising temperature and affecting the
stability of diamonds. Overall, our result suggests
a unified petrological and seismic continental thickness and a tectonic plate defined by partial melt.
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We thank H. Grutter for providing data sources from his extended
abstract from the 8th International Kimberlite Conference,
T. Gernon and M. De Wit for their comments on an earlier version
of the manuscript, and the anonymous reviewers for their insightful
comments. The seismic data used in this study are available at
the Incorporated Research Institutions for Seismology (IRIS)
data management center ( http://ds.iris.edu/ds/nodes/dmc) and
were downloaded using the Standing Order for Data (SOD) package
( http://seis.sc.edu/sod). Supported by Natural Environment
Research Council grant NE/M003507/1 and European Research
Council grant GA 638665.
Materials and Methods
Figs. S1 to S7
Tables S1 to S3
1 March 2017; accepted 21 June 2017
The dual frontier: Patented inventions
and prior scientific advance
Mohammad Ahmadpoor1,2 and Benjamin F. Jones1,2,3*
The extent to which scientific advances support marketplace inventions is largely
unknown. We study 4.8 million U.S. patents and 32 million research articles to
determine the minimum citation distance between patented inventions and prior
scientific advances. We find that most cited research articles (80%) link forward to
a future patent. Similarly, most patents (61%) link backward to a prior research article.
Linked papers and patents typically stand 2 to 4 degrees distant from the other domain.
Yet, advances directly along the patent-paper boundary are notably more impactful
within their own domains. The distance metric further provides a typology of the fields,
institutions, and individuals involved in science-to-technology linkages. Overall, the
findings are consistent with theories that emphasize substantial and fruitful connections
between patenting and prior scientific inquiry.
Scientific research can propel both funda- mental understanding and practical appli- cation, but the extent to which scientific advances support technological progress is unclear (1–3). According to the “linear
model” of science, basic research, focused on
understanding, provides a foundation for eventual
technological applications (1, 4–7). For example,
Riemannian geometry, an abstract mathematical
advance that was initially widely ignored, later
proved essential to Einstein’s development of
general relativity and, ultimately, to time dilation
corrections in the Global Positioning System. In
biology, basic research into extremophile bacteria
later proved essential to the development of the
polymerase chain reaction, the DNA amplification
technique that is vital to modern biotechnology
applications. Such examples illustrate the poten-
tial value of the linear model as a conception of
scientific and technological progress, a view that
helps motivate the public case for supporting
scientific research (1, 8, 9).
At the same time, many observers argue that
basic research rarely pays off in practical application or that practical advances typically proceed without any inspiration from basic research
(10–14). These views suggest a potentially substantial disconnect between the knowledge outputs
of public science institutions, such as research
universities or government laboratories, and inventive outputs in the private sector. Other scholars argue for a richer interplay between scientific
and technological progress. Characterizing scientific progress as advances in understanding
and technological progress as advances in use,
a common theme emphasizes that investigators
focused on questions of use, engaged in solving
real problems, may in turn generate new understandings and progress in basic science (2, 15–17).
For example, Pasteur’s germ theory of disease
was closely intertwined with his work on industrial fermentation and food safety applications,
1Northwestern University, Kellogg School of Management,
Evanston, IL 60208, USA. 2Northwestern University Institute
on Complex Systems and Data Science, Evanston, IL 60208,
USA. 3NBER, Cambridge, MA 02138, USA.
*Corresponding author. Email: email@example.com