measurement process affecting the state of the photon. The original proposal allowed the wave
and particle nature of light to be interchanged after the light had entered the interferometer. By
contrast in this study, entanglement allowed the wave and particle nature to be interchanged after
the light was detected and revealed the quantum nature of the photon, for example, it displays
wave- and particle-like behavior simultaneously.
Annular Solar Eclipse
May 11, 2013
For many types of low-cost solar cells, including those using dye-sensitized titania, performance is
limited by low open-circuit voltages. Lee et al. (p. 643, published online 4 October; see the Per-
spective by Norris and Aydil) have developed a solid-state cell in which structured films of titania
or alumina nanoparticles are solution coated with a lead-halide perovskite layer that acts as the
absorber and n-type photoactive layer. These particles are coated with a spirobifluorene organic-
hole conductor in a solar cell with transparent oxide and metal contacts. For the alumina particles,
power conversion efficiencies of up to 10.9% were obtained.
Chloroplast Rescued by Ubiquitin
The ubiquitin proteasome system is important in the regulation of many nucleocytosolic processes.
However, its regulatory reach was not thought to extend to the chloroplast. Using a forward-genetic
screen in Arabidopsis, Ling et al. (p. 655; see the Perspective by Kessler) identified a ubiquitin E3
ligase, termed SP1, embedded in the chloroplast outer envelope membrane. SP1 was found to target
components of the chloroplast protein import machinery for degradation by the ubiquitin protea-
some and was important for changes in chloroplast biogenesis.
For a detailed brochure,
Necrophilic Bandit Fungi
please call (800) 252-4910
All prices are per person twin share + air
Explore one of the world’s greatest
wilderness areas—the Kimberley in
Northwest Australia—and see the
Annular Solar Eclipse May 11, 2013
in Tennant Creek. Explore Darwin,
Kakadu, and the Kimberley—a vast
and virtually inaccessible area so
remote that very few people have
ever been there! End in Broome,
with a dazzling sand beach, dinosaur
footprints, and more! $9,550 + air
May 2-21, 2013
17050 Montebello Rd, Cupertino, CA 95014
BETCHART EXPEDITIONS Inc.
The immune systems that plants use to defend against patho-
gens normally deflect attack. However, Lorang et al. (p. 659,
published online 18 October) have identified a rearguard
susceptibility that a necrotrophic fungus exploits. The fungal
toxin victorin interacts with the defense protein LOV1 in
Arabidopsis and activates it, but the result, counterintuitively,
is that the plant succumbs to the disease rather than fighting
it off. What seems to be happening is that victorin targets a
thioredoxin that regulates the systemic acquired resistance
pathway. That interaction triggers activity of LOV1, which in
turn incites cell death. The invading fungus then benefits
from the ready access to dead cells.
A long-standing question is whether and how stem cells maintain their epigenetic information.
Knowing that many types of stem cells undergo asymmetric cell divisions, Tran et al. (p. 679)
probed the asymmetric division of Drosophila male germline stem cells and found that preexisting
histones were selectively segregated to the stem cell, whereas new histones were enriched in the
daughter cell that underwent differentiation. By contrast, asymmetric histone distribution was not
seen in progenitor cells. This study suggests that stem cells retain preexisting canonical histones
during asymmetric cell divisions in vivo.
CREDI T: LORANG E T AL.
Two categories of reasons for why poor people make economically unsound choices, such as obtaining
a payday loan at an extraordinarily high rate of interest, reflect, first, the environment: Poor people
are more likely to be living in poor neighborhoods with higher rates of crime and lower rates of social
services. Second, they reflect the individual: People are poor in part because of their own psychological
dispositions toward impatience and impulsiveness. For both cases, obtaining causal evidence in con-
trolled experiments has been challenging. Shah et al. (p. 682; see the Perpective by Zwane) propose a
third category of reasons whereby being poor exerts a bias on cognitive processes and provide evidence
for it in laboratory experiments performed in scenarios of scarcity.
Around the world, governments turn to AAAS
as an objective, multidisciplinary scientific
authority to educate public officials and
judicial figures on today’s most pressing
issues. And this is just one of the ways that
AAAS is committed to advancing science to
support a healthy and prosperous world.
Join us. Together we can make a difference.
AAAS is here –
Science Funding, Climate
Regulation, Human Rights.
To learn more, visit