41,001 research outputs found
Information Flow in an R and D Laboratory
Statistical analysis of hypotheses concerning roles of technological gatekeeper and primary groups in flow of information in small research and development laborator
Innovation and Foreign Investment Behavior of the U.S. Pharmaceutical Industry
This paper deals with the links between the development of new drugs, and particularly of innovative new drugs, and the international activities of U.S. drug companies. While U.S. drug companies have developed new production processes - the most notable being the fermentation process for making penicillin - we concentrate in this paper on new products. Since production costs comprise less than 40 percent of the selling price of drugs and since the person choosing the drug rarely pays for it, growth in company sales and profits comes more from introducing new products than from cutting costs and prices of old products. The main novelty of our study is our examination of "innovative" as contrasted with "imitative" new drugs. Previous studies have generally focused on the total number of new drugs produced each year, but since our interest is in the causes and consequences of innovation, we have concentrated on the products we have rated as innovative. Section I explains our criteria for this distinction and presents our enumeration of the innovative new drugs for each of the 22 companies in our sample. In Section II we discuss trends in the rate of drug innovation and the factors influencing those trends. Section III describes our sample of drug companies and characterizes them with respect to their size, research investment, and innovativeness. Section IV examines the relation of innovativeness to the foreign activities of individual firms. In Section V we analyze, for a sample of 7 new drugs introduced by two companies, the rate at which use of the drugs was diffused among various countries arid the impact of the presence of manufacturing plants on the rate of diffusion.
Fracture of a viscous liquid
When a viscous liquid hits a pool of liquid of same nature, the impact region
is hollowed by the shock. Its bottom becomes extremely sharp if increasing the
impact velocity, and we report that the curvature at that place increases
exponentially with the flow velocity, in agreement with a theory by Jeong and
Moffatt. Such a law defines a characteristic velocity for the collapse of the
tip, which explains both the cusp-like shape of this region, and the
instability of the cusp if increasing (slightly) the impact velocity. Then, a
film of the upper phase is entrained inside the pool. We characterize the
critical velocity of entrainment of this phase and compare our results with
recent predictions by Eggers
The Dynamics of Stellar Coronae Harboring Hot-jupiters II. A Space Weather Event on A Hot-jupiter
We carry out a numerical simulation depicting the effects of a Coronal Mass
Ejection (CME) event on a close-in giant planet in an extrasolar system. We
drive the CME in a similar manner as in simulations of space weather events on
Earth. The simulation includes the planetary orbital motion, which leads to the
forming of a comet-like planetary magnetotail which is oriented almost
perpendicular to the direction of propagation of the CME. The combination of
this feature and the fact that the CME does not expand much by the time it
reaches the planet leads to a unique CME-magnetosphere interaction, where the
CME itself is highly affected by the presence of the planetary magnetosphere.
We find that the planet is well-shielded from CME penetration, even for a
relatively weak internal magnetic field. The planetary angular momentum loss
associated with such an event is negligible compared to the total planetary
angular momentum. We also find that the energy which is deposited in the
magnetosphere is much higher than in the case of the Earth, and our simulation
suggests there is a large-scale change in the orientation of the
magnetosphere-ionosphere current system during the CME event.Comment: 16 pages, 10 figures, accepted to Ap
Rendezvous of Two Robots with Constant Memory
We study the impact that persistent memory has on the classical rendezvous
problem of two mobile computational entities, called robots, in the plane. It
is well known that, without additional assumptions, rendezvous is impossible if
the entities are oblivious (i.e., have no persistent memory) even if the system
is semi-synchronous (SSynch). It has been recently shown that rendezvous is
possible even if the system is asynchronous (ASynch) if each robot is endowed
with O(1) bits of persistent memory, can transmit O(1) bits in each cycle, and
can remember (i.e., can persistently store) the last received transmission.
This setting is overly powerful.
In this paper we weaken that setting in two different ways: (1) by
maintaining the O(1) bits of persistent memory but removing the communication
capabilities; and (2) by maintaining the O(1) transmission capability and the
ability to remember the last received transmission, but removing the ability of
an agent to remember its previous activities. We call the former setting
finite-state (FState) and the latter finite-communication (FComm). Note that,
even though its use is very different, in both settings, the amount of
persistent memory of a robot is constant.
We investigate the rendezvous problem in these two weaker settings. We model
both settings as a system of robots endowed with visible lights: in FState, a
robot can only see its own light, while in FComm a robot can only see the other
robot's light. We prove, among other things, that finite-state robots can
rendezvous in SSynch, and that finite-communication robots are able to
rendezvous even in ASynch. All proofs are constructive: in each setting, we
present a protocol that allows the two robots to rendezvous in finite time.Comment: 18 pages, 3 figure
Model Independent Extraction of Without Heavy Quark Symmetry
A new method to extract is proposed based on a sum--rule for
semileptonic decays of the meson. The method relies on much weaker
assumptions than previous approaches which are based on heavy--quark symmetry.
This sum--rule only relies on the assumption that the virtual
pair content of the meson can be neglected. The extraction of the CKM
matrix element also requires that the sum--rule saturates in the kinematically
accessible region.Comment: 10 pages revtex3 manuscript. No figures, U. of MD PP #94--086. With
our apologies, some innocuous errors corrected and some references added that
had been brought to our attentio
Estimation risk and incentive contracts for portfolio managers
Includes bibliographical references (p. 30)
Hyperfine Anomaly of Be Isotopes and Anomalous Large Anomaly in Be
A new result of investigations of the hyperfine structure (hfs) anomaly in Be
isotopes is presented. The hfs constant for Be is obtained by using the
core plus neutron type wave function: . A large hfs anomaly of Be is found, which is mainly due
to a large radius of the halo single particle state.Comment: 14 pages, Late
The Interaction of Venus-like, M-dwarf Planets with the Stellar Wind of Their Host Star
We study the interaction between the atmospheres of Venus-like,
non-magnetized exoplanets orbiting an M-dwarf star, and the stellar wind using
a multi-species Magnetohydrodynaic (MHD) model. We focus our investigation on
the effect of enhanced stellar wind and enhanced EUV flux as the planetary
distance from the star decreases. Our simulations reveal different topologies
of the planetary space environment for sub- and super-Alfvenic stellar wind
conditions, which could lead to dynamic energy deposition in to the atmosphere
during the transition along the planetary orbit. We find that the stellar wind
penetration for non-magnetized planets is very deep, up to a few hundreds of
kilometers. We estimate a lower limit for the atmospheric mass-loss rate and
find that it is insignificant over the lifetime of the planet. However, we
predict that when accounting for atmospheric ion acceleration, a significant
amount of the planetary atmosphere could be eroded over the course of a billion
years.Comment: 13 pages, 7 figures, accepted to Ap
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