bluuebunny/crossref_metadata_2025 huggingface dataset:
Gambling On a Martian Landing Site
Authors: Kerr Richard A.
Published: October 2006

After two-and-a-half years of balancing scientific interest and safety, scientists have chosen a landing site for the Mars Pathfinder mission, which will give planetary scientists their first close-up look at the Martian surface in 20 years. The choice was an exercise in anxiety, because images of the Martian surface are too coarse to show the cliffs and boulders that could spell disaster when the lander drops to the surface. Team members had to rely on inference and guesswork, and that has led them to a flat plain near the Martian equator, formed billions of years ago when a huge flood burst from a narrow channel.
Panels Look for Common Ground
Authors: Kaiser Jocelyn
Published: October 2006

Efforts are heating up to come up with a governmentwide definition of scientific misconduct. Last week a committee of government research officials began what they hope will be a 3-month effort to draft a definition of research misconduct and guidelines that would apply to all agencies, and next month a working group at the Department of Health and Human Services is expected to recommend misconduct policies for the department. In the meantime, the National Academy of Sciences has stepped into the fray with a letter harshly critical of some of the proposals being discussed.
AIDS Pathogenesis: A Finite Immune Response to Blame?
Authors: Miedema Frank , Klein Michèl R.
Published: October 2006

Some rare individuals infected with the HIV virus do not develop AIDS, and their immune systems remain healthy indefinitely. In a report in this issue of
Science
, Wolinsky
et al
. describe several indices of immune system function in six of these long-term survivors. In their Perspective, Miedema and Klein discuss what these exceptional cases reveal about the more usual course of events for infected individuals—collapse of the immune system and development of AIDS.
Relaunching Bell Labs
Authors: Service Robert F.
Published: October 2006

AT&T's fabled research shop has a new parent called Lucent Technologies, a new boss, and promises that the job cuts that have plagued the physical sciences division are over. Many researchers had been bemoaning the demise of the labs, whose researchers count the development of the transistor, laser, and solar cell among a remarkable stream of breakthroughs that have garnered seven Nobel Prizes during the last 70 years. Yet despite encouraging news from the top, some staff are still sending out résumés.
Cosmologists Beat Out Mars Explorers
Authors: Gavaghan Helen
Published: October 2006

Europe's cosmologists were the winners last week in the competition for the next slot in the European Space Agency's (ESA's) space science program. Following a 3-day meeting at ESA headquarters in Paris, the agency's Space Science Advisory Committee backed COBRAS/SAMBA, a mission to map the cosmic microwave background, a radiation echo of the universe from shortly after the big bang. The decision may, however, spell the end for European scientists' efforts to join international plans to explore Mars.
Wiley Drops IQ Book After Public Furor
Authors: Holden Constance
Published: October 2006

Psychologist Christopher Brand of Edinburgh University got some extensive prepublication publicity for his new book on IQ earlier this month when he made some provocative comments to reporters on race differences in IQ. But the publicity won't help sales: As a result of the furor his remarks touched off, the publisher, John Wiley & Sons, withdrew the book on the eve of publication. Edinburgh University, following student protests and calls for Brand's dismissal, has arranged for an inquiry into his teaching. Meanwhile, Brand's supporters are calling on academics to boycott Wiley.
Molecule Promises a Better Buckyball
Authors: Bradley David
Published: October 2006

Some of the bloom is off the buckyball—the soccerball-shaped carbon molecule that has been all the rage for the past 5 years. Because buckyballs are made in the flash of an electric arc, with no chance to manipulate their structure as they form, they are difficult to modify for specific purposes, such as creating new catalysts or electronic materials. A strategy for making buckyball-like molecules by the techniques of synthetic chemistry, however, may touch off a new ball game. The starting ingredient is corannulene, a basket-shaped molecule that can be covered to make a molecular cavity like that of a buckyball.
Likely HIV Cofactor Found
Authors: Cohen Jon
Published: October 2006

Researchers learned some 12 years ago that the AIDS virus, HIV, needs to latch onto a cell protein called CD4 to enter and infect cells. But they've known for a decade that CD4 by itself is not sufficient to get the virus into cells. Also required is some unknown “cofactor.” That cofactor eluded their efforts to discover it, however, until perhaps now. Work reported in this issue indicates that the cofactor is a protein called fusin, a discovery that may help solve several mysteries about AIDS. Among them: how HIV destroys cells and why it appears not to harm some infected people. It may also be possible to limit HIV infectivity by designing new drugs that work by binding to fusin.
California Social Climbers: Low Water Prompts High Status
Authors: Fischman Joshua
Published: October 2006

New Orleans—You wouldn't know it from watching Hollywood's glitterati vie for choice tables at posh eateries, but life in Southern California wasn't always so status-conscious. One thousand years ago the original inhabitants, the Chumash, were an egalitarian society of hunter-gatherers. By the 1700s, however, they had acquired chiefs, ranks, and other social divisions. Archaeologists have often thought such changes occur gradually, but there's emerging evidence that social rank among the Chumash was born from a sudden episode of drought—and what one researcher calls “a crucible of violence.”
Solar and Thermal Radiation in Jupiter's Atmosphere: Initial Results of the Galileo Probe Net Flux Radiometer
Authors: Sromovsky L. A. , Best F. A. , Collard A. D. , Fry P. M. , Revercomb H. E. , Freedman R. S. , Orton G. S. , Hayden J. L. , Tomasko M. G. , Lemmon M. T.
Published: October 2006

The Galileo probe net flux radiometer measured radiation within Jupiter's atmosphere over the 125-kilometer altitude range between pressures of 0.44 bar and 14 bars. Evidence for the expected ammonia cloud was seen in solar and thermal channels down to 0.5 to 0.6 bar. Between 0.6 and 10 bars large thermal fluxes imply very low gaseous opacities and provide no evidence for a deep water cloud. Near 8 bars the water vapor abundance appears to be about 10 percent of what would be expected for a solar abundance of oxygen. Below 8 bars, measurements suggest an increasing water abundance with depth or a deep cloud layer. Ammonia appears to follow a significantly subsaturated profile above 3 bars. Unexpectedly high absorption of sunlight was found at wavelengths greater than 600 nanometers.
Homologous DNA Pairing Promoted by a 20-Amino Acid Peptide Derived from RecA
Authors: Voloshin Oleg N. , Wang Lijiang , Camerini-Otero R. Daniel
Published: October 2006

The molecular structure of the
Escherichia coli
RecA protein in the absence of DNA revealed two disordered or mobile loops that were proposed to be DNA binding sites. A short peptide spanning one of these loops was shown to carry out the key reaction mediated by the whole RecA protein: pairing (targeting) of a single-stranded DNA to its homologous site on a duplex DNA. In the course of the reaction the peptide bound to both substrate DNAs, unstacked the single-stranded DNA, and assumed a β structure. These events probably recapitulate the underlying molecular pathway or mechanism used by homologous recombination proteins.
Requirement of p27
Kip1
for Restriction Point Control of the Fibroblast Cell Cycle
Authors: Coats Steve , Flanagan W. Michael , Nourse Jamison , Roberts James M.
Published: October 2006

Cells deprived of serum mitogens will either undergo immediate cell cycle arrest or complete mitosis and arrest in the next cell cycle. The transition from mitogen dependence to mitogen independence occurs in the mid- to late G
1
phase of the cell cycle and is called the restriction point. Murine Balb/c-3T3 fibroblasts deprived of serum mitogens accumulated the cyclin-dependent kinase (CDK) inhibitor p27
Kip1
. This was correlated with inactivation of essential G
1
cyclin-CDK complexes and with cell cycle arrest in G
1
. The ability of specific mitogens to allow transit through the restriction point paralleled their ability to down-regulate p27, and antisense inhibition of p27 expression prevented cell cycle arrest in response to mitogen depletion. Therefore, p27 is an essential component of the pathway that connects mitogenic signals to the cell cycle at the restriction point.
Photon Bubbles Put X-ray Fizz Into Neutron Stars
Authors: Glanz James
Published: October 2006

Since its launch last December, NASA's Rossi X-ray Timing Explorer satellite has found that the x-ray signals from some neutron stars oscillate as fast as 1100 times a second—faster than any existing picture of these x-ray sources can explain. These observations have opened the way to a new theory of what happens when superheated matter crashes onto the surface of the neutron star, sparking the x-ray emissions. The theory, tested in supercomputer simulations, attributes the high-frequency oscillations to bubbles of x-rays that form and burst in the infalling matter.
Selected Elastic Moduli of Single-Crystal Olivines from Ultrasonic Experiments to Mantle Pressures
Authors: Chen Ganglin , Li Baosheng , Liebermann Robert C.
Published: October 2006

Ultrasonic interferometric measurements, developed for polycrystalline samples in a multi-anvil apparatus, were extended to single-crystal samples of San Carlos olivine and forsterite. The elastic moduli,
C
22
and
C
55
of San Carlos olivine and
C
55
of pure forsterite, were measured to about 13 gigapascals. These data on
C
22
for San Carlos olivine and
C
55
for forsterite are consistent with earlier measurements and extrapolations. The
C
55
for San Carlos olivine increases linearly as a function of increasing pressure, unlike the earlier nonlinear behavior observed at high pressure with impulsive stimulated scattering techniques.
Big Projects Could Threaten Weapons Labs' Research Base
Authors: Lawler Andrew
Published: October 2006

Los Alamos, New Mexico—The decision to stop underground nuclear testing has made computer simulations the chief tool for ensuring that the U.S. nuclear arsenal is reliable. But a $4 billion program, called stockpile stewardship and management, has triggered a fierce debate within the defense community. At issue is how to balance the cost of such new facilities as the $1.1 billion National Ignition Facility, which will simulate the conditions of nuclear detonation, with the need to keep enough experienced weapons designers on hand for core research activities.
A Second Spell in the Science Hot Seat
Authors: Biggin Susan
Published: October 2006

Venice—After a year and a half of government by nonpartisan “technocrats,” Italian voters last month restored politicians to center stage. Last week, the new government announced that it would form a “superministry” responsible for research and education, and named lawyer Luigi Berlinguer, the former rector of Siena University, to head it. Berlinguer, who has briefly held the post of research minister before, has some tough tasks ahead: increasing funding, reforming the discredited university appointments system, and rescuing the troubled Italian Space Agency.
A “Schrödinger Cat” Superposition State of an Atom
Authors: Monroe C. , Meekhof D. M. , King B. E. , Wineland D. J.
Published: October 2006

A "Schrödinger cat''-like state of matter was generated at the single atom level. A trapped
9
Be
+
ion was laser-cooled to the zero-point energy and then prepared in a superposition of spatially separated coherent harmonic oscillator states. This state was created by application of a sequence of laser pulses, which entangles internal (electronic) and external (motional) states of the ion. The Schrödinger cat superposition was verified by detection of the quantum mechanical interference between the localized wave packets. This mesoscopic system may provide insight into the fuzzy boundary between the classical and quantum worlds by allowing controlled studies of quantum measurement and quantum decoherence.
Prognosis in HIV-1 Infection Predicted by the Quantity of Virus in Plasma
Authors: Mellors John W. , Rinaldo Charles R. , Gupta Phalguni , White Roseanne M. , Todd John A. , Kingsley Lawrence A.
Published: October 2006

The relation between viremia and clinical outcome in individuals infected with human immunodeficiency virus-type 1 (HIV-1) has important implications for therapeutic research and clinical care. HIV-1 RNA in plasma was quantified with a branched-DNA signal amplification assay as a measure of viral load in a cohort of 180 seropositive men studied for more than 10 years. The risk of acquired immunodeficiency syndrome (AIDS) and death in study subjects, including those with normal numbers of CD4
+
T cells, was directly related to plasma viral load at study entry. Plasma viral load was a better predictor of progression to AIDS and death than was the number of CD4
+
T cells.
Structural Basis of Ligand Discrimination by Two Related RNA Aptamers Resolved by NMR Spectroscopy
Authors: Yang Yinshan , Kochoyan Michel , Burgstaller Petra , Westhof Eric , Famulok Michael
Published: October 2006

In a previous study, an RNA aptamer for the specific recognition of arginine was evolved from a parent sequence that bound citrulline specifically. The two RNAs differ at only 3 positions out of 44. The solution structures of the two aptamers complexed to their cognate amino acids have now been determined by two-dimensional nuclear magnetic resonance spectroscopy. Both aptamers contain two asymmetrical internal loops that are not well ordered in the free RNA but that fold into a compact structure upon ligand binding. Those nucleotides common to both RNAs include a conserved cluster of purine residues, three of which form an uneven plane containing a G:G pair, and two other residues nearly perpendicular to that surface. Two of the three variant nucleotides are stacked on the cluster of purines and form a triple contact to the amino acid side chain, whereas the edge of the third variant nucleotide is capping the binding pocket.
Sterol Esterification in Yeast: A Two-Gene Process
Authors: Yang Hongyuan , Bard Martin , Bruner Debora A. , Gleeson Anne , Deckelbaum Richard J. , Aljinovic Gordana , Pohl Thomas M. , Rothstein Rodney , Sturley Stephen L.
Published: October 2006

Unesterified sterol modulates the function of eukaryotic membranes. In human cells, sterol is esterified to a storage form by acyl-coenzyme A (CoA): cholesterol acyl transferase (ACAT). Here, two genes are identified,
ARE1
and
ARE2
, that encode ACAT-related enzymes in yeast. The yeast enzymes are 49 percent identical to each other and exhibit 23 percent identity to human ACAT. Deletion of
ARE2
reduced sterol ester levels to approximately 25 percent of normal levels, whereas disruption of
ARE1
did not affect sterol ester biosynthesis. Deletion of both genes resulted in a viable cell with undetectable esterified sterol. Measurements of [
14
C]acetate incorporation into saponified lipids indicated down-regulation of sterol biosynthesis in the
are1 are2
mutant cells. With the use of a consensus sequence to the yeast and human genes, an additional member of the ACAT gene family was identified in humans.
Seoul Unveils Regional Center
Authors: Normile Dennis
Published: October 2006

Tokyo—Ten Pacific countries are laying claim to a larger Asian presence in theoretical physics this week at a conference in Seoul that marks the debut of a new research organization. The Asian Pacific Center for Theoretical Physics is intended to make the South Korean capital a mecca for researchers by assembling a world-class permanent faculty, offering workshops and meetings, and eventually awarding advanced degrees. It also fulfills a longtime dream of Asian scientists hoping to increase the two-way flow of knowledge between East and West
Chlamydia
Linked to Atherosclerosis
Authors: Mlot Christine
Published: October 2006

The bacteria
Chlamydia
has always been an odd bug, causing an illness in parrots as well as sexually transmitted diseases. Now a recently discovered species,
C. pneumoniae
, offers an even bigger surprise: It consistently turns up in the arteries of patients with atherosclerosis.
Observatory Fades Away in Splendid Isolation
Authors: Stone Richard
Published: October 2006

Abastumani, Georgia—the former Soviet Union's first mountaintop observatory—once did pioneering studies of the Crab Nebula and, with an array of telescopes that includes a 40-centimeter refractor and a 70-centimeter meniscus telescope, discovered more than a dozen supernovas. Today, like most scientific institutions in Georgia, it is fighting for survival. During the winter months, with just 4 hours of electricity a day, room temperatures approach freezing and Abastumani's scientists analyze old data in front of gas stoves in their apartments. Telescopes and support equipment are turned on only for maintenance.
Bose-Einstein Condensates Display Their First Tricks
Authors: Taubes Gary
Published: October 2006

A year ago this month, physicists first created a Bose-Einstein condensate, a state of matter in which a cloud of trapped atoms is cooled so close to absolute zero that their quantum-mechanical waves merge. But with barely 1000 atoms in a condensate that lasted just a few seconds, the researchers could do no more than say they'd done it. Now the field is being transformed by a new atom trap that can create condensates of 5 million sodium atoms that survive for half a minute and a new technique for imaging condensates without destroying them. Several research groups are now probing the size, growth rate, optical properties, and even the viscosity of this new form of matter.
Sending and Receiving the Hedgehog Signal: Control by the

Drosophila

Gli Protein Cubitus interruptus
Authors: Domínguez María , Brunner Martina , Hafen Ernst , Basler Konrad
Published: October 2006

Drosophila
limb development is organized by interactions between anterior and posterior compartment cells. Posterior cells continuously express and require
engrailed
(
en
) and secrete Hedgehog (Hh) protein. Anterior cells express the zinc-finger protein Cubitus interruptus (Ci). It is now shown that anterior cells lacking
ci
express
hh
and adopt posterior properties without expressing
en
. Increased levels of Ci can induce the expression of the Hh target gene
decapentaplegic
(
dpp
) in a Hh-independent manner. Thus, expression of Ci in anterior cells controls limb development (i) by restricting
hh
secretion to posterior cells and (ii) by conferring competence to respond to Hh by mediating the transduction of this signal.
Electrical Properties of the Venus Surface from Bistatic Radar Observations
Authors: Pettengill Gordon H. , Ford Peter G. , Simpson Richard A.
Published: October 2006

A bistatic radar experiment in 1994, involving reception on Earth of a specularly reflected, linearly polarized 13-centimeter-wavelength signal transmitted from the Magellan spacecraft in orbit around Venus, has established that the surface materials viewed at low and intermediate altitudes on Venus have a relative dielectric permittivity of 4.0 ± 0.5. However, bistatic results for the Maxwell Montes highlands imply an electrically lossy surface with an imaginary dielectric permittivity of −
i
100 ± 50, probably associated with a specific conductivity of about 13 mhos per meter. Candidates for highlands surface composition include ferroelectrics, a thin frost of elemental tellurium, or a plating of magnetite or pyrites.
Site-Directed Hydroxyl Radical Probing of the rRNA Neighborhood of Ribosomal Protein S5
Authors: Heilek Gabriele M. , Noller Harry F.
Published: October 2006

Cysteine residues were introduced into three different positions distributed on the surface of ribosomal protein S5, to serve as targets for derivatization with an Fe(II)-ethylenediaminetetraacetic acid linker. Hydroxyl radicals generated locally from the tethered Fe(II) in intermediate ribonucleoprotein particles or in 30
S
ribosomal subunits reconstituted from derivatized S5 caused cleavage of the RNA, resulting in characteristically different cleavage patterns for the three different tethering positions. These findings provide constraints for the three-dimensional folding of 16
S
ribosomal RNA (rRNA) and for the orientation of S5 in the 30
S
subunit, and they further suggest that antibiotic resistance and accuracy mutations in S5 may involve perturbation of 16
S
rRNA.
Putting Some Sizzle in the Corona
Authors: Glanz James
Published: October 2006

Madison, Wisconsin—An instrument aboard the Solar and Heliospheric Observatory satellite has detected 100-million-degree oxygen ions in the suns atmosphere, investigators announced at a meeting of the American Astronomical Society here last week. That temperature is tens of times higher than has ever been measured before in the corona, the sun's halo of ionized gases. But a handful of solar physicists aren't surprised. They say that the detection of superhot oxygen provides crucial support for theories that they have proposed to solve the mystery of what heats the corona to millions of degrees when the surface of the sun is a cool 6000 degrees.
Signaling Inside Neurons Takes Some New Twists
Authors: Barinaga Marcia
Published: October 2006

At Cold Spring Harbor Laboratory's annual Symposium on Quantitative Biology, one of the more surprising developments came from research showing that the same protein, called alpha-gustducin, transmits both sweet and sour signals from their surface receptors to the cell interior. That was unexpected because the two types of signals have opposite effects on intracellular cyclic AMP concentrations, and researchers now need to explain how one protein can achieve both. Also reported at the meeting were new findings indicating that nerve growth factor (NGF), generally known for promoting neuronal survival, can actually kill some nerve cells at an early stage of embryonic development, possibly as part of the normal neuronal pruning that goes on then. NGF apparently acts through a receptor protein called
p
75, although exactly how is unclear.
The Complete 685-Kilobase DNA Sequence of the Human β T Cell Receptor Locus
Authors: Rowen Lee , Koop Ben F. , Hood Leroy
Published: October 2006

The human β T cell receptor (TCR) locus, comprising a complex family of genes, has been sequenced. The locus contains two types of coding elements—TCR elements (65 variable gene segments and two clusters of diversity, joining, and constant segments) and eight trypsinogen genes—that constitute 4.6 percent of the DNA. Genome-wide interspersed repeats and locus-specific repeats span 30 and 47 percent, respectively, of the 685-kilobase sequence. A comparison of the germline variable elements with their approximately 300 complementary DNA counterparts reveals marked differential patterns of variable gene expression, the importance of exonuclease activity in generating TCR diversity, and the predominant tendency for only functional variable elements to be present in complementary DNA libraries.
Ion-Induced Morphological Changes in “Crew-Cut” Aggregates of Amphiphilic Block Copolymers
Authors: Zhang Lifeng , Yu Kui , Eisenberg Adi
Published: October 2006

The addition of ions in micromolar (CaCl
2
or HCl) or millimolar (NaCl) concentrations can change the morphology of “crew-cut” aggregates of amphiphilic block copolymers in dilute solutions. In addition to spherical, rodlike, and univesicular or lamellar aggregates, an unusual large compound vesicle morphology can be obtained from a single block copolymer. Some features of the spontaneously formed large compound vesicles may make them especially useful as vehicles for delivering drugs and as models of biological cells. Gelation of a dilute spherical micelle solution can also be induced by ions as the result of the formation of a cross-linked “pearl necklace” morphology.
Artificial Life Gets Real as Scientists Meet in Japan
Authors: Normile Dennis
Published: October 2006

The mathematicians and computer scientists who form the core of artificial-life enthusiasts have long thought that their evolution-inspired computer techniques can model reality—and even create it. Their enthusiasm was much in evidence at A-Life V, held 16 to 18 May in Nara, Japan, where 500 attendees heard about efforts to evolve useful circuit designs and a model of runaway sexual selection. Computers/Math
HIV Receptors and the Pathogenesis of AIDS
Authors: Weiss Robin A.
Published: October 2006

There are many ways of approaching research on AIDS, and sometimes different philosophies clash. Robin Weiss (Chester Beatty Laboratories, Institute of Cancer Research, UK) wryly portrays the differences between the experimentalists and the theorists as they try to understand how the interactions of HIV and its human host result in disease. He also presents his view that recent discoveries of cofactors for HIV entry highlight the improtance of a cell biology—centered approach to understanding pathogenesis.
Nonselective and G
βγ
-Insensitive

weaver

K
+
Channels
Authors: Navarro Betsy , Kennedy Matthew E. , Velimirović Bratislav , Bhat Deepti , Peterson Andrew S. , Clapham David E.
Published: October 2006

Homozygous
weaver
mice are profoundly ataxic because of the loss of granule cell neurons during cerebellar development. This granule cell loss appears to be caused by a genetic defect in the pore region (Gly
156
→ Ser) of the heterotrimeric guanine nucleotide-binding protein (G protein)-gated inwardly rectifying potassium (K
+
) channel subunit (GIRK2). A related subunit, GIRK1, associates with GIRK2 to constitute a neuronal G protein-gated inward rectifier K
+
channel. The
weaver
allele of the GIRK2 subunit (
wv
GIRK2) caused loss of K
+
selectivity when expressed either as
wv
GIRK2 homomultimers or as GIRK1-
wv
GIRK2 heteromultimers. The mutation also led to loss of sensitivity to G protein β γ dimers. Expression of
wv
GIRK2 subunits led to increased cell death, presumably as a result of basal nonselective channel opening.
Formation of a Transition-State Analog of the Ras GTPase Reaction by Ras·GDP, Tetrafluoroaluminate, and GTPase-Activating Proteins
Authors: Mittal Rohit , Ahmadian Mohammad Reza , Goody Roger S. , Wittinghofer Alfred
Published: October 2006

Unlike the α subunits of heterotrimeric guanosine triphosphate (GTP)-binding proteins, Ras-related GTP-binding proteins have hitherto been considered not to bind or become activated by tetrafluoroaluminate (AlF
4
−
). However, the product of the proto-oncogene
ras
in its guanosine diphosphate (GDP)-bound form interacted with AlF
4
−
in the presence of stoichiometric amounts of either of the guanosine triphosphatase (GTPase)-activating proteins (GAPs) p120
GAP
and neurofibromin. Neither oncogenic Ras nor a GAP mutant without catalytic activity produced such a complex. Together with the finding that the Ras-binding domain of the protein kinase c-Raf, whose binding site on Ras overlaps that of the GAPs, did not induce formation of such a complex, this result suggests that GAP and neurofibromin stabilize the transition state of the GTPase reaction of Ras.
Will There Be
Liebowitz
v.
NAE
?
Authors: Lawler Andrew
Published: October 2006

A history of litigation by its ousted president has the NAE Council worried about the possibility of getting into a legal battle over the terms of his departure.
Muscling Transplants Into Mice
Authors: Wickelgren Ingrid
Published: October 2006

Creating “immune-privileged” pockets where a new heart, liver, or kidney graft would be safe from immunologic rejection has long been a transplant biologist's dream. Now researchers have devised a way to do that by genetically engineering muscle cells to produce a key ingredient of immune privilege: a protein known as the Fas ligand, or FasL, that can induce immune cells to kill themselves. On
page 109
, they report using engineered muscle cells to protect transplants of islet cells, the insulin-producing cells of the pancreas, in diabetic mice—a feat that could lead to a treatment for some human diabetics and perhaps to a general strategy for guarding transplants against rejection.
A Search for Earthquake Precursors
Authors: Silver Paul G. , Wakita Hiroshi
Published: October 2006

Geochemical signals that precede an earthquake might offer the hope of early warning and evacuation. The existence of such precursors is extremely controversial, however, as early optimism has turned into skepticism. In their Perspective, Silver and Wakita discuss new work on precursor events that was presented at a conference in Tokyo. An encouraging trend is emerging because of higher quality data and better analysis of these events.
Foreign Students Bypassing Germany
Authors: Kahn Patricia
Published: October 2006

As Germany's universities sink deeper into crisis, they are also losing their allure for foreigners. While top universities from Boston to Hong Kong are attracting more and more overseas students, the opposite is true in Germany. The reasons are many: The need to study in German; long degree courses lasting 7 years or more; bewildering bureaucracy; and unwelcoming immigration status. The universities' declining internationality prompted a debate in the German parliament last month, and now the government seems to be taking action: offering specially tailored courses for foreign students and easing the regulations over foreign qualifications and language.
Unruly Sun Emerges in Solar Observatory's First Results
Authors: Glanz James
Published: October 2006

Madison, Wisconsin—Watching from the gravitational balance point between Earth and the sun, the Solar and Heliospheric Observatory has spied a virtual bacchanalia of twisting magnetic field lines and turbulent gases in the sun's surface layers and atmosphere. As researchers reported at the American Astronomical Society meeting here last month, the sheer level of activity is unexpected for this point in the 11-year cycle of solar activity, when the sun is supposed to be in a lull. And clues gleaned from the commotion could alter scientists' understanding of how the sun generates its magnetic field, heats its million-degree atmosphere, and flings clouds of ionized gas into space.
Twinkle, Twinkle, Little Quasar
Authors: Schilling Govert
Published: October 2006

Quasars, thought to be the nuclei of very distant young galaxies, are astounding at the best of times, but now Australian radio astronomers have spotted a quasar with an impressive talent: It winks far faster than any quasar previously seen—varying its output by as much as 60% in half an hour. Astronomers are working hard to figure out how something so large can change so fast. Is it the bizarre effects of electrons moving close to the speed of light, or just gas clouds in our own galaxy making the quasar's light twinkle?
The Shrewd Grasp of RNA Polymerase
Authors: Landick Robert , Roberts Jeffrey W.
Published: October 2006

In a paper in this week's issue, Nudler
et al
. (
p. 211
) define the basis of the interaction of DNA with RNA polymerase, the enzyme that synthesizes messenger RNA from DNA. Landick and Roberts describe in their Perspective exactly where that takes us in our ability to describe the transcription machinery and provide a comprehensive figure.
Structure of the Amino-Terminal Core Domain of the HIV-1 Capsid Protein
Authors: Gitti Rossitza K. , Lee Brian M. , Walker Jill , Summers Michael F. , Yoo Sanghee , Sundquist Wesley I.
Published: October 2006

The three-dimensional structure of the amino-terminal core domain (residues 1 through 151) of the human immunodeficiency virus-type 1 (HIV-1) capsid protein has been solved by multidimensional heteronuclear magnetic resonance spectroscopy. The structure is unlike those of previously characterized viral coat proteins and is composed of seven α helices, two β hairpins, and an exposed partially ordered loop. The domain is shaped like an arrowhead, with the β hairpins and loop exposed at the trailing edge and the carboxyl-terminal helix projecting from the tip. The proline residue Pro
1
forms a salt bridge with a conserved, buried aspartate residue (Asp
51
), which suggests that the amino terminus of the protein rearranges upon proteolytic maturation. The binding site for cyclophilin A, a cellular rotamase that is packaged into the HIV-1 virion, is located on the exposed loop and encompasses the essential proline residue Pro
90
. In the free monomeric domain, Pro
90
adopts kinetically trapped cis and trans conformations, raising the possibility that cyclophilin A catalyzes interconversion of the
cis-
and
trans-
Pro
90
loop structures.
Upgraded LEP Bags First W Pairs
Authors: Watson Andrew
Published: October 2006

Just 2 days after restarting their main accelerator following a major upgrade, physicists at CERN, Europe's particle physics center near Geneva, witnessed their first creation of pairs of so-called W particles, the charged carriers of the weak nuclear force, which controls some types of radioactivity as well as the nuclear burning of the sun. The upgraded Large Electron-Positron (LEP) collider, dubbed LEP2, was designed to produce W pairs, and physicists can now study the particles in detail. At this higher energy, physicists will also be on the lookout for two long-sought-after quarries: the Higgs particle, linked to the mechanism which gives particles mass; and supersymmetry, a unifying principle in many attempts to combine all of nature's forces.
India Struggles to Handle an Embarrassment of Riches
Authors: Bagla Pallava
Published: October 2006

New Delhi—A number of high-volume users have begun to complain quietly that India's network of remote sensing satellites—an international technological jewel—is too slow, expensive, and cumbersome to serve their needs. They say its full potential for helping public officials and private organizations keep tabs on everything from schools of fish to soil erosion cannot be realized unless the government eases obstacles—including military restrictions—to the data's availability and concentrates on making the system more user-friendly.
The Biosphere Is Going Deep
Authors: Fyfe W. S.
Published: October 2006

Recent work in Earth system science shows that living organisms have much more of an influence on the composition of solid Earth than had ever been anticipated. Fyfe reviews the results that point to the presence of influential microorganisms several kilometers deep into the solid Earth.
Hormone Mimicry
Authors: Wells James A.
Published: October 2006

Two research articles in this week's
Science
[Livnah
et al
. (
p. 464
) and Wrighton
et al
. (
p. 458
)] report the isolation and structure of a 20-amino acid peptide that binds to and activates the receptor for erythropoietin but is not derived from the normal ligand. In his Perspective, Wells describes the unique selection procedure that allowed this accomplishment and what it means for drug development.
Small Peptides as Potent Mimetics of the Protein Hormone Erythropoietin
Authors: Wrighton Nicholas C. , Farrell Francis X. , Chang Ray , Kashyap Arun K. , Barbone Francis P. , Mulcahy Linda S. , Johnson Dana L. , Barrett Ronald W. , Jolliffe Linda K. , Dower William J.
Published: October 2006

Random phage display peptide libraries and affinity selective methods were used to isolate small peptides that bind to and activate the receptor for the cytokine erythropoietin (EPO). In a panel of in vitro biological assays, the peptides act as full agonists and they can also stimulate erythropoiesis in mice. These agonists are represented by a 14- amino acid disulfide-bonded, cyclic peptide with the minimum consensus sequence YXCXXGPXTWXCXP, where X represents positions allowing occupation by several amino acids. The amino acid sequences of these peptides are not found in the primary sequence of EPO. The signaling pathways activated by these peptides appear to be identical to those induced by the natural ligand. This discovery may form the basis for the design of small molecule mimetics of EPO.
Persistent Site-Specific Remodeling of a Nucleosome Array by Transient Action of the SWI/SNF Complex
Authors: Owen-Hughes T. , Utley R. T. , Côté J. , Peterson C. L. , Workman J. L.
Published: October 2006

The SWI/SNF complex participates in the restructuring of chromatin for transcription. The function of the yeast SWI/SNF complex in the remodeling of a nucleosome array has now been analyzed in vitro. Binding of the purified SWI/SNF complex to a nucleosome array disrupted multiple nucleosomes in an adenosine triphosphate-dependent reaction. However, removal of SWI/SNF left a deoxyribonuclease I-hypersensitive site specifically at a nucleosome that was bound by derivatives of the transcription factor Gal4p. Analysis of individual nucleosomes revealed that the SWI/SNF complex catalyzed eviction of histones from the Gal4-bound nucleosomes. Thus, the transient action of the SWI/SNF complex facilitated irreversible disruption of transcription factor-bound nucleosomes.
Does Nature Drive Nurture?
Authors: Cohen Jon
Published: October 2006

Behavioral geneticists have so far identified few, if any, genes that control specific behaviors in higher species like mammals. But a research team at Harvard Medical School has now come up with a good candidate: the
fosB
gene, which their work suggests is needed for normal nurturing behavior in mice. When the gene is inactivated, mother mice neglect their pups.
Ancient Remedy Performs New Tricks
Authors: Mervis Jeffrey
Published: October 2006

An improved cancer therapy for a rare blood cancer called acute promyelocytic leukemia (APL) may be the result of a merger between traditional Chinese medicine and modern molecular biology. A team of researchers in Shanghai and Harbin, China, has found that arsenic trioxide, the active ingredient in a traditional Chinese remedy for a variety of ailments, can induce remissions in up to 70% of APL patients. It apparently achieves this by triggering apoptosis (programmed cell death) in APL cells. The results have excited Western oncologists, who recall that a decade ago the same team both developed the current clinical treatment for APL and helped to uncover how it functions within the cell.
Yeast Prions: DNA-Free Genetics?
Authors: Vogel Gretchen
Published: October 2006

Prions—infectious protein particles thought to cause “mad cow disease,” human Creutzfeldt-Jakob disease, and other neurological afflictions—now seem to be running rampant in yeast. But there's no reason to stop eating bread or drinking beer, for there's not even a hint that yeast prions pose a health threat. On the contrary, they may help scientists figure out how a protein can perpetuate a trait—or a disease—from one cell to the next without involving DNA or RNA. On
page 622
, researchers show that a form-changing protein in yeast appears to create a trait called [PSI
+
] in daughter yeast cells, after they bud off a mother cell, by causing newly synthesized proteins to become relatively insoluble and clump together. It does so without altering the DNA in the cells, which are clones.
Europe and Japan Burst Ahead on Neutron Facilities
Authors: Lawler Andrew
Published: October 2006

To the envy of U.S. researchers, neutron science enjoys strong support from European and Japanese governments. Last week German officials broke ground on a $500 million research reactor outside Munich that is expected to consolidate Europe's position as the leader in the field for at least the next two decades. Meanwhile, Japanese researchers are awaiting final approval for a neutron source to be added to the $700 million Japan Hadron Project. Ironically, U.S. companies remain preeminent in their use of neutron sources—but their quest for the best facilities increasingly takes them across the ocean.
Calculated Clusters
Authors: Voss David
Published: October 2006

Recent calculations offer a way to learn about the geometric structure of small clusters of atoms and at the same time reveal interesting physical properties.
How Congressional Pressure Shaped the 'Baltimore Case'
Authors: Friedly Jock
Published: October 2006

One of the most high-profile scientific misconduct cases collapsed recently when all charges against immunologist Thereza Imanishi-Kari were dismissed. The crucial ingredient in keeping the case grinding along was the active interest of Representative John Dingell (D-MI), chairman of a key congressional subcommittee. Subcommittee investigators, some of whom were being paid by the National Institutes of Health (NIH), were involved in virtually every aspect of the case, from the selection of evidence to its public dissemination.
Biomimetic Pathways for Assembling Inorganic Thin Films
Authors: Aksay I. A. , Trau M. , Manne S. , Honma I. , Yao N. , Zhou L. , Fenter P. , Eisenberger P. M. , Gruner S. M.
Published: October 2006

Living organisms construct various forms of laminated nanocomposites through directed nucleation and growth of inorganics at self-assembled organic templates at temperatures below 100°C and in aqueous solutions. Recent research has focused on the use of functionalized organic surfaces to form continuous thin films of single-phase ceramics. Continuous thin films of mesostructured silicates have also been formed on hydrophobic and hydrophilic surfaces through a two-step mechanism. First, under acidic conditions, surfactant micellar structures are self-assembled at the solid/liquid interface, and second, inorganic precursors condense to form an inorganic-organic nanocomposite. Epitaxial coordination of adsorbed surfactant tubules is observed on mica and graphite substrates, whereas a random arrangement is observed on amorphous silica. The ability to process ceramic-organic nanocomposite films by these methods provides new technological opportunities.
An Archean Geomagnetic Reversal in the Kaap Valley Pluton, South Africa
Authors: Layer Paul W. , Kröner Alfred , McWilliams Michael
Published: October 2006

The Kaap Valley pluton in South Africa is a tonalite intrusion associated with the Archean Barberton Greenstone Belt. Antipodal paleomagnetic directions determined from the central and marginal parts of the pluton record a geomagnetic reversal that occurred as the pluton cooled. The age of the reversal is constrained by an
40
Ar/
39
Ar plateau age from hornblende at 3214 ± 4 million years, making it the oldest known reversal. The data presented here suggest that Earth has had a reversing, perhaps dipolar, magnetic field since at least 3.2 billion years ago.
New Satellite Puts Japan in Top Tier of Remote Sensing
Authors: Normile Dennis
Published: October 2006

Tokyo—Japan's remote Earth-sensing program took off last weekend when an H-II rocket lofted the $1 billion Advanced Earth Observing Satellite (ADEOS) into orbit from the Tanegashima Space Center. The satellite, with eight instruments from three nations measuring everything from stratospheric ozone to ocean turbulence, is a significant addition to the growing international fleet of spacecraft peering down on Earth's environment. But for Japan's National Space Development Agency, ADEOS also marks the start of an ambitious effort to go beyond its traditional role as a rocket and satellite developer and become a major player in research. If all goes according to plan, ADEOS will be joined by three more earth-science satellites by 2000.
Lattices May Put Security Codes on a Firmer Footing
Authors: Cipra Barry
Published: October 2006

Computer security experts have developed powerful techniques for encrypting data so that only the intended recipient, armed with the right key, can retrieve it. But these codes come without any absolute guarantee of security, because the mathematical problems they are based on may not be as hard to solve as they appear. A recent discovery in theoretical computer science comes close to providing such a guarantee by showing that examples picked from one class of problems are almost certain to be hard—the basis for an uncrackable code. Computers/Math.
Complete Genome Sequence of the Methanogenic Archaeon,

Methanococcus jannaschii
Authors: Bult Carol J. , White Owen , Olsen Gary J. , Zhou Lixin , Fleischmann Robert D. , Sutton Granger G. , Blake Judith A. , FitzGerald Lisa M. , Clayton Rebecca A. , Gocayne Jeannine D. , Kerlavage Anthony R. , Dougherty Brian A. , Tomb Jean-Francois , Adams Mark D. , Reich Claudia I. , Overbeek Ross , Kirkness Ewen F. , Weinstock Keith G. , Merrick Joseph M. , Glodek Anna , Scott John L. , Geoghagen Neil S. M. , Weidman Janice F. , Fuhrmann Joyce L. , Nguyen Dave , Utterback Teresa R. , Kelley Jenny M. , Peterson Jeremy D. , Sadow Paul W. , Hanna Michael C. , Cotton Matthew D. , Roberts Kevin M. , Hurst Margaret A. , Kaine Brian P. , Borodovsky Mark , Klenk Hans-Peter , Fraser Claire M. , Smith Hamilton O. , Woese Carl R. , Venter J. Craig
Published: October 2006

The complete 1.66-megabase pair genome sequence of an autotrophic archaeon,
Methanococcus jannaschii
, and its 58- and 16-kilobase pair extrachromosomal elements have been determined by whole-genome random sequencing. A total of 1738 predicted protein-coding genes were identified; however, only a minority of these (38 percent) could be assigned a putative cellular role with high confidence. Although the majority of genes related to energy production, cell division, and metabolism in
M. jannaschii
are most similar to those found in Bacteria, most of the genes involved in transcription, translation, and replication in
M. jannaschii
are more similar to those found in Eukaryotes.

The
Methanococcus jannaschii
Genome Database
Evidence for Supersonic Turbulence in the Upper Atmosphere of Jupiter
Authors: Emerich Claude , Jaffel Lotfi Ben , Clarke John T. , Prangé Renée , Gladstone G. Randall , Sommeria Joel , Ballester Gilda
Published: October 2006

Spectra of the hydrogen Lyman α (Ly-α) emission line profiles of the jovian dayglow, obtained by the Goddard High Resolution Spectrograph on the Hubble Space Telescope, appear complex and variable on time scales of a few minutes. Dramatic changes occur in the Ly-α bulge region at low latitudes, where the line profiles exhibit structures that correspond to supersonic velocities of the order of several to tens of kilometers per second. This behavior, unexpected in a planetary atmosphere, is evidence for the particularly stormy jovian upper atmosphere, not unlike a star's atmosphere.
Simultaneous Measurement of Local Gain and Electron Density in X-ray Lasers
Authors: Cauble R. , Da Silva L. B. , Barbee T. W. , Celliers P. , Decker C. , London R. A. , Moreno J. C. , Trebes J. E. , Wan A. S. , Weber F.
Published: October 2006

X-ray lasers (XRLs) have experimental average gains that are significantly less than calculated values and a persistently low level of spatial coherence. An XRL has been used both as an injected signal to a short XRL amplifier and as an interferometer beam to measure two-dimensional local gain and density profiles of the XRL plasma with a resolution near 1 micrometer. The measured local gain is in agreement with atomic models but is unexpectedly spatially inhomogeneous. This inhomogeneity is responsible for the low level of spatial coherence observed and helps explain the disparity between observed and simulated gains.