bluuebunny/crossref_metadata_2025 huggingface dataset:
Antiviral Activity of Arabinosyladenine and Arabinosylhypoxanthine in Herpes Simplex Virus-Infected KB Cells: Selective Inhibition of Viral Deoxyribonucleic Acid Synthesis in Synchronized Suspension Cultures
Authors: Shipman Charles , Smith Sandra H. , Carlson Roger H. , Drach John C.
Published: June 2012

The drug 9-β-
d
-arabinofuranosyladenine (ara-A) significantly suppressed the formation of herpes simplex virus type 1-induced syncytia in BHK-21/4 cells at concentrations as low as 0.1 μg/ml. Optimal activity was noted when the drug was added before initiation of viral deoxyribonucleic acid (DNA) synthesis (3.5 h postinfection). The deaminated derivative of ara-A, 9-β-
d
-arabinofuranosylhypoxanthine (ara-H), was at least 10 times less effective in suppressing the development of herpes simplex virus-induced syncytia. The replication of herpes simplex virus was measured by assaying fluids and cells from infected drug-treated cultures by using a plaque production technique. Ara-A at drug levels of >10 < 32 μg/ml completely blocked the replication of infectious virus particles. Ara-H was less effective than ara-A in reducing the replication of virions. Rates of host and viral DNA synthesis were monitored by pulse labeling herpes simplex virus-infected synchronized KB cells with [
3
H]thymidine and subsequently separating viral from cellular DNA in CsCl density gradients. During synthetic (S) phase, ara-A or ara-H at concentrations ranging from 3.2 to 32 μg/ml selectively inhibited viral DNA synthesis. At 3.2 μg of ara-A per ml, viral DNA synthesis was reduced 74% although total cellular DNA synthesis was unaffected. Increasing concentrations of ara-A produced increasing temporal delays in the maximal rate of host DNA synthesis. This time shift was not observed in cells treated with ara-H.
Inhibition of Peptidoglycan Cross-Linking in Growing Cells of
Escherichia coli
by Penicillins and Cephalosporins, and Its Prevention by R Factor-Mediated Beta-Lactamase
Authors: Curtis Nigel A. C. , Hughes Julia M. , Ross Gordon W.
Published: June 2012

The degree of peptidoglycan cross-linking has been studied in growing cells of a Dap
−
Lys
−
auxotroph of
Escherichia coli
K-12 by following the incorporation of [
3
H]diaminopimelic acid into the lysozyme digestion products of crude, isolated peptidoglycan. The percentage of inhibition of cross-linking increases with increasing concentrations of penicillin G, cephaloridine, and cefuroxime. When the R factor R1
drd
19 was introduced into the strain by conjugation, it was found that the type IIIa, β-lactamase specified by the plasmid was able to protect the cross-linking target against inhibition by penicillin G but not against cephaloridine, even though the β-lactamase hydrolyzes this substrate 50% faster than penicillin G. Cefuroxime, which is completely resistant to hydrolysis by the type IIIa β-lactamase, inhibited the peptidoglycan cross-linking target in both the R
+
and R
−
variants of the assay strain. A mutant plasmid, R1
drd
19
amp
2, which specified no type IIIa β-lactamase synthesis, could not provide protection of the cross-linking target against penicillin G. The significance of these results, in relation to the ability of the antibiotics to pass the permeability barrier of the bacterial envelope, is discussed.
Metronidazole Bioassay
Authors: Speck William T. , Stein Aaron B. , Rosenkranz Herbert S.
Published: June 2012

Urine from patients receiving metronidazole [1-(2-hydroxyethyl)-2-methyl-5-nitromidazole] orally or per vagina were subjected to paper chromatographic fractionation and examined for anticlostridial activity. Unmodified metronidazole and several metabolites were detected. These findings indicate that the clostridial bioassay may be limited in its applicability to the study of the pharmacodynamics of metronidazole as it does not differentiate between the parent substance and some of its metabolites. Moreover, some of the latter, although they possess antibacterial activity, may not have antiprotozoan activity.
Evaluation of Antibiotic Efficacy Using Electron Microscopy: Morphological Effects of Guanylureido Cephalosporin, BL-P1654, and Carbenicillin on
Escherichia coli
Authors: Ellis L. F. , Herron D. K. , Preston D. A. , Simmons L. K. , Schlegel R. A.
Published: June 2012

Early response of
Escherichia coli
to minimal inhibitory concentrations of 112883, BL-P1654, and carbenicillin was determined by [
14
C]leucine uptake and scanning electron microscopy morphology studies. [
14
C]leucine uptake was inhibited later by carbenicillin than by BL-P1654 or 112883. Cellular swelling at 30 min, septal region swelling, and lysis were the progressive morphological changes with BL-P1654 and 112883. Carbenicillin-treated cells showed septal region swelling, beaded chains, and lysis.
In Vitro Studies of Cefamandole
Authors: Bodey Gerald P. , Weaver Susanne
Published: June 2012

Cefamandole is a new cephalosporin antibiotic that was tested in vitro against 540 clinical isolates of gram-positive cocci and gram-negative bacilli. A concentration of 0.39 μg/ml inhibited 95% of the isolates of
Staphylococcus aureus
. A concentration of 6.25 μg/ml inhibited over 90% of the isolates of
Proteus mirabilis
and
Escherichia coli
, 69% of the isolates of
Klebsiella pneumoniae
, and 31% of the isolates of indole-positive
Proteus
spp. and
Enterobacter
spp. It was active against most cephalothin-resistant isolates of
E. coli
but not of
K. pneumoniae
.
Association of a Penicillin Resistance Gene with a Tetracycline Resistance Plasmid (P
TP–2
) in
Staphylococcus aureus
Authors: Kono Megumi , Sasatsu Masanori
Published: June 2012

On transduction with a lysogenic strain of
Straphylococcus aureus
isolated from a clinical specimen and having tetracycline (TC)-penicillin (PC)-chloramphenicol (CP)-resistant plasmids, the three-drug-resistant strain was frequently obtained. By repeatedly transducing from this strain, a strain (TP-2) having stable resistance to TC and PC could be obtained. In transformation with the deoxyribonucleic acid (DNA) of TP-2 as donor, all of the transformants obtained by selecting with either TC or PC were both TC and PC resistant. According to electron microscopy study of the covalently closed circular DNA of TP-2, the plasmid DNA size was 1.37 ± 0.03 μm (2.84 × 10
6
daltons). The plasmid (P
TP-2
) is presumed to be a new plasmid in which the PC resistance gene was integrated into the TC-resistant plasmid.
Resistance Plasmids of
Pseudomonas aeruginosa:
Change from Conjugative to Nonconjugative in a Hospital Population
Authors: Korfhagen Thomas R. , Ferrel James A. , Menefee Constance L. , Loper John C.
Published: June 2012

Properties of a population of carbenicillin- and gentamicin-resistant, tobramycin-susceptible
Pseudomonas aeruginosa
at Veteran's Administration Hospital, Cincinnati, Ohio, have been followed during a 16-month period. As originally described, the strains were isolated from patients with urinary tract colonizations and were predominantly Parke-Davis immunotype 7. For the majority of these organisms, antibiotic resistance was correlated with the presence of a self-conjugative plasmid of incompatibility group P-2. The source and relative incidence of multiply resistant isolates have remained constant during the current study, but the immunotype has shifted form type 7 to type 2. Concomitantly, the population has lost the property of conjugative transfer of resistance, and resistant strains are now compatible with P-2 plasmids. A group P-2 R plasmid, pMG5, will mobilize resistance markers, demonstrating that the multiple resistance of the nonconjugative strains is mediated by R plasmids. Additionally, gentamicin resistance due to either conjugative or nonconjugative plasmids is correlated with the presence of similar gentamicin acetyltransferase activity. pMG5-mobilized plasmids are shown to be incompatible with pMG5. pMG5 is also shown to mobilize resistance markers from nontransferring antibiotic-resistant strains representing populations from Parkland Memorial Hospital, Dallas, Texas, and Cleveland Clinic Foundation, Cleveland, Ohio.
Carbenicillin in the Treatment of Infections Involving Anaerobic Bacteria
Authors: Swenson Robert M. , Lorber Bennett
Published: June 2012

Twenty-one patients with serious infections involving anaerobic bacteria were treated with carbenicillin. Multiple anaerobes were involved in 8 cases, and in 10 cases, facultative anaerobes were also isolated.
Bacteroides fragilis
was isolated in 10 cases. Results were judged excellent in 7 cases, good in 8 cases, and fair in 5 cases. These data suggest that carbenicillin may be an effective antibiotic for the therapy of infections due to anaerobic bacteria, particularly those involving
B. fragilis
.
Antibiotic Resistance Among Coliform and Fecal Coliform Bacteria Isolated from Sewage, Seawater, and Marine Shellfish
Authors: Cooke Marylyn D.
Published: June 2012

Seawater and shellfish samples collected in the vicinity of a marine sewage outfall were examined for the incidence of antibiotic resistance among coliform and fecal coliform bacteria over a 2-year period. Seventy percent or more of these two groups of bacteria from both sources were resistant to one or more antibiotics. Forty-five percent of the isolates resistant to streptomycin or tetracycline were capable of transferring all or part of their resistance pattern to an antibiotic-susceptible strain of
Escherichia coli
K-12.
Laboratory Studies with a New Broad-Spectrum Penicillin, Pirbenicillin
Authors: Retsema James A. , English Arthur R. , Lynch John E.
Published: June 2012

Pirbenicillin {6-[
d
-2-phenyl-2(
N
-4-pyridylformimidoylaminoacetamido) -acetamido]-penicillanic acid} showed broad-spectrum antibacterial activity in vitro and also in the treatment of experimental infections after parenteral administration to mice. Against
Pseudomonas aeruginosa
, a three- to fourfold potency advantage over carbenicillin was seen both in vitro and in vivo. The in vitro antibacterial spectrum of pirbenicillin includes
Escherichia coli, Serratia, Citrobacter
, and
Enterobacter
isolates, against which it exhibited minimal inhibitory concentration values comparable to those of carbenicillin. However, mice infected with
E. coli
and
Serratia
were protected at doses of pirbenicillin that were two to four times lower than those required of carbenicillin. Pirbenicillin was more active than carbenicillin against gram-positive bacteria, especially
Streptococcus faecalis
. It was less active than carbenicillin against
Proteus
spp. and was inactive against ampicillin-resistant
E. coli
strains. Pirbenicillin was bactericidal at concentrations generally equal to or only two-fold higher than the minimal inhibitory concentration. With appropriately buffered media, pirbenicillin demonstrated eight- and fourfold better minimal bactericidal concentration values towards
Pseudomonas
isolates than those of carbenicillin and ticarcillin, respectively.
Expression of the Laccase Gene from a White Rot Fungus in Pichia pastoris Can Enhance the Resistance of This Yeast to H
2
O
2
-Mediated Oxidative Stress by Stimulating the Glutathione-Based Antioxidative System
Authors: Yang Yang , Fan Fangfang , Zhuo Rui , Ma Fuying , Gong Yangmin , Wan Xia , Jiang Mulan , Zhang Xiaoyu
Published: June 2012

Laccase is a copper-containing polyphenol oxidase that has great potential in industrial and biotechnological applications. Previous research has suggested that fungal laccase may be involved in the defense against oxidative stress, but there is little direct evidence supporting this hypothesis, and the mechanism by which laccase protects cells from oxidative stress also remains unclear. Here, we report that the expression of the laccase gene from white rot fungus in
Pichia pastoris
can significantly enhance the resistance of yeast to H
2
O
2
-mediated oxidative stress. The expression of laccase in yeast was found to confer a strong ability to scavenge intracellular H
2
O
2
and to protect cells from lipid oxidative damage. The mechanism by which laccase gene expression increases resistance to oxidative stress was then investigated further. We found that laccase gene expression in
Pichia pastoris
could increase the level of glutathione-based antioxidative activity, including the intracellular glutathione levels and the enzymatic activity of glutathione peroxidase, glutathione reductase, and γ-glutamylcysteine synthetase. The transcription of the laccase gene in
Pichia pastoris
was found to be enhanced by the oxidative stress caused by exogenous H
2
O
2
. The stimulation of laccase gene expression in response to exogenous H
2
O
2
stress further contributed to the transcriptional induction of the genes involved in the glutathione-dependent antioxidative system, including
PpYAP1
,
PpGPX1
,
PpPMP20
,
PpGLR1
, and
PpGSH1
. Taken together, these results suggest that the expression of the laccase gene in
Pichia pastoris
can enhance the resistance of yeast to H
2
O
2
-mediated oxidative stress by stimulating the glutathione-based antioxidative system to protect the cell from oxidative damage.
Fluid Flow Induces Biofilm Formation in Staphylococcus epidermidis Polysaccharide Intracellular Adhesin-Positive Clinical Isolates
Authors: Weaver Westbrook M. , Milisavljevic Vladana , Miller Jeff F. , Di Carlo Dino
Published: June 2012

Staphylococcus epidermidis
is a common cause of catheter-related bloodstream infections, resulting in significant morbidity and mortality and increased hospital costs. The ability to form biofilms plays a crucial role in pathogenesis; however, not all clinical isolates form biofilms under normal
in vitro
conditions. Strains containing the
ica
operon can display significant phenotypic variation with respect to polysaccharide intracellular adhesin (PIA)-based biofilm formation, including the induction of biofilms upon environmental stress. Using a parallel microfluidic approach to investigate flow as an environmental signal for
S. epidermidis
biofilm formation, we demonstrate that fluid shear alone induces PIA-positive biofilms of certain clinical isolates and influences biofilm structure. These findings suggest an important role of the catheter microenvironment, particularly fluid flow, in the establishment of
S. epidermidis
infections by PIA-dependent biofilm formation.
Electrical Conductivity in a Mixed-Species Biofilm
Authors: Malvankar Nikhil S. , Lau Joanne , Nevin Kelly P. , Franks Ashley E. , Tuominen Mark T. , Lovley Derek R.
Published: June 2012

Geobacter sulfurreducens
can form electrically conductive biofilms, but the potential for conductivity through mixed-species biofilms has not been examined. A current-producing biofilm grown from a wastewater sludge inoculum was highly conductive with low charge transfer resistance even though microorganisms other than
Geobacteraceae
accounted for nearly half the microbial community.
The Australian Primary Care Collaboratives Program: improving diabetes care
Authors: Knight Andrew W , Ford Dale , Audehm Ralph , Colagiuri Stephen , Best James
Published: June 2012

Problem

Diabetes is a major, growing health problem often managed in primary care but with suboptimal control of risk factors.

Design

A large-scale quality improvement collaborative implemented in seven waves.

Setting

General practices and Aboriginal medical services across Australia.

Key measures for improvement

Percentage of patients in each health service with haemoglobin A1C (HbA1C), total cholesterol and blood pressure at target.

Strategy for change

Health services attended three 2-day workshops, separated by 3-month activity periods and followed by 12 months of further improvement work. Local collaborative program managers supported teams to report measures and plan/do/study/act (PDSA) cycles monthly. Health services received feedback about changes in their measures in comparison with their wave.

Effects of change

743 health services participated in seven waves between 2004 and 2009 serving approximately 150 000 people with diabetes. Mean numbers of patients at target HbA1c levels improved by 50% from 25% at baseline to 38% at month 18. Lipid and blood pressure measures showed similar improvement.

Lessons learnt

Engagement in the Program and results demonstrated that the collaborative methodology is transferable to Australian primary care. The results may reflect improved data recording and disease coding, and changes in clinical care. Internal evaluation should be built into improvement projects from the start to facilitate improvements and reporting. Enthusing, training and resourcing practice teams appeared to be the key to rapid change. Local support of practice teams was instrumental in improvement. Early investment to facilitate automatic measure collection ensured good data reporting.
Costs of injury in New Zealand: Accident Compensation Corporation spending, personal spending and quality-adjusted life years lost
Authors: Wilson Ross , Derrett Sarah , Hansen Paul , Langley John Desmond
Published: June 2012

Background

New Zealand offers a unique opportunity for cost-of-injury research due to its comprehensive, no-fault injury compensation insurance scheme, which is managed by the government-controlled Accident Compensation Corporation (ACC).

Objectives

To estimate the costs of injury in New Zealand with respect to ACC's spending for entitlement claimants (ie, people with injuries requiring more than ‘treatment only’), as well as injured individuals' out-of-pocket personal spending and non-pecuniary costs in terms of effects on health-related quality of life (HRQoL).

Methods

A prospective cohort study of people injured between June 2007 and May 2009 was followed for 12 months after injury. ACC's spending for each participant (n=2215) was estimated from ACC data. Out-of-pocket personal spending and quality-adjusted life years (QALYs) lost were estimated based on interviews conducted at 3, 5 and 12 months post injury.

Results

For the cohort studied, most of the reported financial costs of injury were met by ACC. ACC spending was higher for individuals with more severe injuries and ones admitted to hospital. There was no difference in mean personal spending between people who were hospitalised or not, or between those with minor or moderate injuries, although individuals with more severe injuries reported higher personal spending.

Conclusions

Overall, the ACC appears to be performing well supporting injured people financially. Nonetheless, people with more severe injuries incur substantial out-of-pocket expenses. Costs are higher for hospitalised and more severe injuries, but non-hospitalised and less severe cases can still incur substantial costs. The HRQoL effects of injury—naturally, borne by injured individuals themselves—are relatively large on average.
The changing relationship between income and mortality in Finland, 1988–2007
Authors: Tarkiainen Lasse , Martikainen Pekka , Laaksonen Mikko
Published: June 2012

Background

Socioeconomic mortality differences have increased in many high-income countries in recent decades mainly because of slower mortality decline among the lower social groups. The aim of this study was to investigate whether the changing socio-demographic composition explains the increasing disparity in mortality by income and the stagnation of mortality in the lowest income group.

Methods

The register data comprised a nationally representative 11% sample of individuals aged 35–64 years residing in Finland in 1988–2007, linked with mortality records. Household taxable income was used as the income measure. Poisson regression models were used to assess the changes in mortality disparity among the income quintiles between periods 1988–1991, 1996–1999 and 2004–2007. The measures of socio-demographic composition included educational level, social class, employment status and living alone.

Results

The mortality rate ratio (with the highest quintile as the reference category) of the lowest quintile increased from 2.80 to 5.16 among the men and from 2.17 to 4.23 among the women between 1988–1991 and 2004–2007. Controlling for other socio-demographic variables strongly attenuated the differences, but the rate ratio of the lowest quintile still increased from 1.32 to 1.73 among the men and from 1.13 to 1.66 among the women. There was no decline in the fully adjusted mortality of the lowest quintiles between second and third study periods.

Conclusions

Socio-demographic characteristics explained much of the mortality disparity between income quintiles within each study period. However, these characteristics do not explain the increasing disparity between the periods and stagnating mortality in the lowest quintile.
ADAPTIVE K-MEANS ALGORITHM FOR OVERLAPPED GRAPH CLUSTERING
Authors: BELLO-ORGAZ GEMA , MENÉNDEZ HÉCTOR D. , CAMACHO DAVID
Published: June 2012

The graph clustering problem has become highly relevant due to the growing interest of several research communities in social networks and their possible applications. Overlapped graph clustering algorithms try to find subsets of nodes that can belong to different clusters. In social network-based applications it is quite usual for a node of the network to belong to different groups, or communities, in the graph. Therefore, algorithms trying to discover, or analyze, the behavior of these networks needed to handle this feature, detecting and identifying the overlapped nodes. This paper shows a soft clustering approach based on a genetic algorithm where a new encoding is designed to achieve two main goals: first, the automatic adaptation of the number of communities that can be detected and second, the definition of several fitness functions that guide the searching process using some measures extracted from graph theory. Finally, our approach has been experimentally tested using the Eurovision contest dataset, a well-known social-based data network, to show how overlapped communities can be found using our method.
STRUCTURAL AND ELECTRONIC PROPERTIES OF ZINCBLENDE AlInN ALLOY: A HYBRID DENSITY FUNCTIONAL STUDY
Authors: WANG FEI , YUAN PENGFEI , WANG YUCANG , WANG SANJUN , SUN QIANG , JIA YU
Published: June 2012

Conventional local and semilocal density functionals cannot predict correct bandgap energy for semiconductors especially the indium compounds. By employing the density functional theory calculations with a hybrid functional, we studied the bandgap energy and structure properties of AlN and InN compounds as well as their ternary AlInN alloys. We showed that by adjusting the screening parameter in the hybrid functional, the bandgaps calculated are in good agreement with the experimental data. A 2.54 eV natural valence band offset between AlN and InN is found with the hybrid density functional study. Furthermore, we studied the bandgap and band bowing parameter for AlInN alloys by using the hybrid density functional. The bandgap and band bowing parameters obtained are consistent with experimental and other theoretical results. Our results revealed that, although the PBE functional underestimates the bandgap energy for binary compound and ternary AlInN alloy, their band bowing parameters are still reasonable and valid. Our results should be useful for experiment and optoelectronic device applications.
TEXT LOCATION IN SCENE IMAGES USING VISUAL ATTENTION MODEL
Authors: SUN QIAO-YU , LU YUE
Published: June 2012

Locating text region from an image of nature scene is significantly helpful for better understanding the semantic meaning of the image, which plays an important role in many applications such as image retrieval, image categorization, social media processing, etc. Traditional approach relies on the low level image features to progressively locate the candidate text regions. However, these approaches often suffer for the cases of the clutter background since the adopted low level image features are fairly simple which may not reliably distinguish text region from the clutter background. Motivated by the recent popular research on attention model, salience detection is revisited in this paper. Based on the case of text detection on nature scene image, saliency map is further analyzed and is adjusted accordingly. Using the adjusted saliency map, the candidate text regions detected by the common low level features are further verified. Moreover, efficient low level text feature, Histogram of Edge-direction (HOE), is adopted in this paper, which statistically describes the edge direction information of the region of interest on the image. Encouraging experimental results have been obtained on the nature scene images with the text of various languages.
A PHENOMENOLOGICAL OPERATOR DESCRIPTION OF INTERACTIONS BETWEEN POPULATIONS WITH APPLICATIONS TO MIGRATION
Authors: BAGARELLO FABIO , OLIVERI FRANCESCO
Published: June 2012

We adopt an operatorial method based on the so-called creation, annihilation and number operators in the description of different systems in which two populations interact and move in a two-dimensional region. In particular, we discuss diffusion processes modeled by a quadratic Hamiltonian. This general procedure will be adopted, in particular, in the description of migration phenomena. With respect to our previous analogous results, we use here fermionic operators since they automatically implement an upper bound for the population densities.
E-POINTS FOR DIAGONAL GAMES III
Authors: MARCHI EZIO
Published: June 2012

In this paper we study and compute E-points in an explicit way for a special kind of diagonal games with 3k + 1, 4k + 3 and sk + 1 players where 1 ≤ s ≤ k.
GENERATION OF UNIFORM HAZARD EARTHQUAKE ACCELEROGRAMS AND NEAR-FIELD GROUND MOTIONS
Authors: FATEMI A. A. , BAGHERI A. , AMIRI G. GHODRATI , GHAFORY-ASHTIANY M.
Published: June 2012

The sets of records developed for the SAC Steel Project are classified according to the level of seismic hazard and specific geographic region, and have been used extensively for structural response and seismic hazard analyses. This study presents a parametric analysis of these record data sets for generation of uniform hazard earthquake and near-field records. The record parameters define far-field characteristics such as power spectral density and envelope function, and near-field effects such as acceleration pulse, power spectral density and envelope function. The proposed method for generation of near-field records uses the decomposing capabilities of wavelet transform on earthquake records. A set of uniform hazard earthquake accelerograms and near-field ground motions is generated based on the record parameters. The generated uniform hazard earthquake accelerograms representing a uniform level of seismic hazard for a particular geographic region involves seismic hazard studies, calibrated attenuation relationships, and local site amplification models. In order to assess the reliability and efficiency of the presented method, the statistical response spectra obtained from the generated accelerograms have been compared with those from the actual records. The obtained results showed that there is a good compatibility between the response spectra of the generated and actual records in the most of the frequencies.
Wireless, Ultra-Low-Power Implantable Sensor for Chronic Bladder Pressure Monitoring
Authors: Majerus Steve J. A. , Garverick Steven L. , Suster Michael A. , Fletter Paul C. , Damaser Margot S.
Published: June 2012

The wireless implantable/intracavity micromanometer (WIMM) system was designed to fulfill the unmet need for a chronic bladder pressure sensing device in urological fields such as urodynamics for diagnosis and neuromodulation for bladder control. Neuromodulation in particular would benefit from a wireless bladder pressure sensor which could provide real-time pressure feedback to an implanted stimulator, resulting in greater bladder capacity while using less power. The WIMM uses custom integrated circuitry, a MEMS transducer, and a wireless antenna to transmit pressure telemetry at a rate of 10 Hz. Aggressive power management techniques yield an average current draw of 9μA from a 3.6-Volt micro-battery, which minimizes the implant size. Automatic pressure offset cancellation circuits maximize the sensing dynamic range to account for drifting pressure offset due to environmental factors, and a custom telemetry protocol allows transmission with minimum overhead. Wireless operation of the WIMM has demonstrated that the external receiver can receive the telemetry packets, and the low power consumption allows for at least 24 hours of operation with a 4-hour wireless recharge session.
Adaptive Optics for Astronomy
Authors: Davies Richard , Kasper Markus
Published: June 2012

Adaptive optics is a prime example of how progress in observational astronomy can be driven by technological developments. At many observatories it is now considered to be part of a standard instrumentation suite, enabling ground-based telescopes to reach the diffraction limit and, thus, providing spatial resolution superior to that achievable from space with current or planned satellites. In this review, we consider adaptive optics from the astrophysical perspective. We show that adaptive optics has led to important advances in our understanding of a multitude of astrophysical processes and describe how the requirements from science applications are now driving the development of the next generation of novel adaptive optics techniques.
Magnetic Fields in Molecular Clouds
Authors: Crutcher Richard M.
Published: June 2012

This review examines observations of magnetic fields in molecular clouds and what those observations tell us about the theory of molecular cloud evolution and star formation. First, the review briefly summarizes classes of theoretical models of molecular clouds and specific predictions of the models that can be tested by observation. Then, the review describes the techniques for observing and mapping magnetic fields in molecular clouds, followed by discussion of important examples of observational studies using each technique. A synthesis of results from all observational techniques summarizes the current state, which is that though magnetic fields generally dominate turbulence, there is no definitive evidence for magnetic fields dominating gravity in molecular clouds or for ambipolar-diffusion-driven star formation. Finally, the review discusses prospects for advances in our observational capabilities with telescopes and instruments now beginning operation or under construction.
Planet-Disk Interaction and Orbital Evolution
Authors: Kley W. , Nelson R.P.
Published: June 2012

As planets form and grow within gaseous protoplanetary disks, the mutual gravitational interaction between the disk and planet leads to the exchange of angular momentum and migration of the planet. We review current understanding of disk-planet interactions, focusing in particular on physical processes that determine the speed and direction of migration. We describe the evolution of low-mass planets embedded in protoplanetary disks and examine the influence of Lindblad and corotation torques as a function of the disk properties. The role of the disk in causing the evolution of eccentricities and inclinations is also discussed. We describe the rapid migration of intermediate-mass planets that may occur as a runaway process and examine the transition to gap formation and slower migration driven by the viscous evolution of the disk for massive planets. The roles and influence of disk self-gravity and magnetohydrodynamic turbulence are discussed in detail, as a function of the planet mass, as is the evolution of multiple planet systems. Finally, we address the question of how well global models of planetary formation that include migration are able to match observations of extrasolar planets.
Seeing Cosmology Grow
Authors: Peebles P.J.E.
Published: June 2012

The modest science of cosmology I encountered a half century ago has grown into big science. I comment on steps in this development I think I understand because I was there or, in some cases, wish I had been. Wonderful insights—or lucky guesses—and elegant deductions from measurements were accompanied by the usual mix of unlucky guesses and disregard of unwelcome evidence. I say “usual” because I suspect the course of development of any other natural science is similarly erratic. An example in cosmology is Einstein's homogeneous Universe, which was largely accepted as a working hypothesis when there was scant evidence and seriously challenged after we had a reasonable case for homogeneity. Similar mixes of insight and inattention led to the eventual identification of the 3K microwave background, the demonstration that large-scale structure grew by the gravitational instability of the expanding Universe, and the completion of a tight network of cosmological tests. A half century ago, we had little idea what would become of what we were doing in cosmology. We have a better picture now, but I expect there to be more surprises.
Presupernova Evolution of Massive Single and Binary Stars
Authors: Langer N.
Published: June 2012

Understanding massive stars is essential for a variety of branches of astronomy including galaxy and star cluster evolution, nucleosynthesis and supernovae, pulsars, and black holes. It has become evident that massive star evolution is very diverse, being sensitive to metallicity, binarity, rotation, and possibly magnetic fields. Although the problem to obtain a good statistical observational database is alleviated by current large spectroscopic surveys, it remains a challenge to model these diverse paths of massive stars toward their violent end stage.

I show that the main sequence stage offers the best opportunity to gauge the relevance of the various possible evolutionary scenarios. This also allows sketching the post-main-sequence evolution of massive stars, for which observations of Wolf-Rayet stars give essential clues. Recent supernova discoveries owing to the current boost in transient searches allow tentative mappings of progenitor models with supernova types, including pair-instability supernovae and gamma-ray bursts.
Critical Reactions in Contemporary Nuclear Astrophysics
Authors: Wiescher M. , Käppeler F. , Langanke K.
Published: June 2012

Nuclear reaction rates play a critical role in the understanding of stellar evolution and explosions. However, in many cases nuclear reaction rates still carry large uncertainties due to the paucity of experimental data and incomplete theoretical understanding of the underlying reaction mechanisms. New experimental methods and techniques, combined with the development of new theoretical tools, have exposed fresh avenues to pursue nuclear reactions of significance for nucleosynthesis at, or near, the actual temperatures of stellar burning. This review provides an overview of the most critical nuclear reactions for a number of nucleosynthesis environments. It also presents the current status of these reactions and provides insight into the specific uncertainties associated with the reaction rates. We identify existing shortcomings in the data and highlight the needs and opportunities for additional future experiments.
The Economics and Politics of Women's Rights
Authors: Doepke Matthias , Tertilt Michèle , Voena Alessandra
Published: June 2012

Women's rights and economic development are highly correlated. Today, the discrepancy between the legal rights of women and men is much larger in developing compared with developed countries. Historically, even in countries that are now rich, women had few rights before economic development took off. Is development the cause of expanding women's rights, or conversely, do women's rights facilitate development? We argue that there is truth to both hypotheses. The literature on the economic consequences of women's rights documents that more rights for women lead to more spending on health and children, which should benefit development. The political-economy literature on the evolution of women's rights finds that technological change increased the costs of patriarchy for men and thus contributed to the expansion of women's rights. Combining these perspectives, we discuss the theory of Doepke & Tertilt (2009) , who find that an increase in the return to human capital induces men to vote for women's rights, which in turn promotes growth in human capital and income per capita.
Heterogeneity in Human Capital Investments: High School Curriculum, College Major, and Careers
Authors: Altonji Joseph G. , Blom Erica , Meghir Costas
Published: June 2012

Motivated by the large differences in labor market outcomes across college majors, we survey the literature on the demand for and return to high school and postsecondary education by field of study. We combine elements from several papers to provide a dynamic model of education and occupation choice that stresses the roles of the specificity of human capital and uncertainty about preferences, ability, education outcomes, and labor market returns. The model implies an important distinction between the ex ante and ex post returns to education decisions. We also discuss some of the econometric difficulties in estimating the causal effects of field of study on wages in the context of a sequential choice model with learning. Finally, we review the empirical literature on the choice of curriculum and the effects of high school courses and college major on labor market outcomes.
Behavioral Economics and Psychology of Incentives
Authors: Kamenica Emir
Published: June 2012

Monetary incentives can backfire while nonstandard interventions, such as framing, can be effective in influencing behavior. I review the empirical evidence on these two sets of anomalies. Paying for inherently interesting tasks, paying for prosocial behavior, paying too much, paying too little, and providing too many options can all be counterproductive. At the same time, proper design of the decision-making environment can be a potent way to induce certain behaviors. After presenting the empirical evidence, I discuss the relative role of beliefs, preferences, and technology in the anomalous impacts of incentives. I argue that inference, signaling, loss aversion, dynamic inconsistency, and choking are the primary factors that explain the data.
Corruption in Developing Countries
Authors: Olken Benjamin A. , Pande Rohini
Published: June 2012

Recent years have seen a remarkable expansion in economists' ability to measure corruption. This in turn has led to a new generation of well-identified, microeconomic studies. We review the evidence on corruption in developing countries in light of these recent advances, focusing on three questions: how much corruption is there, what are the efficiency consequences of corruption, and what determines the level of corruption? We find robust evidence that corruption responds to standard economic incentive theory but also that the effects of anticorruption policies often attenuate as officials find alternate strategies to pursue rents.
Credit Constraints in Education
Authors: Lochner Lance , Monge-Naranjo Alexander
Published: June 2012

We review studies of the impact of credit constraints on the accumulation of human capital. Evidence suggests that credit constraints have recently become important for schooling and other aspects of households' behavior. We highlight the importance of early childhood investments, as their response largely determines the impact of credit constraints on the overall lifetime acquisition of human capital. We also review the intergenerational literature and examine the macroeconomic impacts of credit constraints on social mobility and the income distribution. A common limitation across all areas of the human capital literature is the imposition of ad hoc constraints on credit. We propose a more careful treatment of the structure of government student loan programs and the incentive problems underlying private credit. We show that endogenizing constraints on credit for human capital helps explain observed borrowing, schooling, and default patterns and offers new insights about the design of government policy.
The Relationship Between Economic Preferences and Psychological Personality Measures
Authors: Becker Anke , Deckers Thomas , Dohmen Thomas , Falk Armin , Kosse Fabian
Published: June 2012

Although both economists and psychologists seek to identify determinants of heterogeneity in behavior, they use different concepts to capture them. In this review, we first analyze the extent to which economic preferences and psychological concepts of personality, such as the Big Five and locus of control, are related. We analyze data from incentivized laboratory experiments and representative samples and find only low degrees of association between economic preferences and personality. We then regress life outcomes (such as labor market success, health status, and life satisfaction) simultaneously on preference and personality measures. The analysis reveals that the two concepts are rather complementary when it comes to explaining heterogeneity in important life outcomes and behavior.
The Empirics of Firm Heterogeneity and International Trade
Authors: Bernard Andrew B. , Jensen J. Bradford , Redding Stephen J. , Schott Peter K.
Published: June 2012

This article reviews the empirical evidence on firm heterogeneity in international trade. A first wave of empirical findings from microdata on plants and firms proposed challenges for existing models of international trade and inspired the development of new theories emphasizing firm heterogeneity. Subsequent empirical research has examined additional predictions of these theories and explored other dimensions of the data not originally captured by them. These other dimensions include multiproduct firms, offshoring, intrafirm trade and firm export market dynamics.
Endogenous Extreme Events and the Dual Role of Prices
Authors: Danielsson Jon , Shin Hyun Song , Zigrand Jean-Pierre
Published: June 2012

Extreme events in financial markets are often generated by shocks that come from within the system, rather than those that arrive from outside the system. The combination of risk-sensitive behavior rules and the coordinated actions implied by market-to-market accounting can result in outcome distributions with fat tails, even if the fundamental shocks are Gaussian. We illustrate such endogenous extreme events through the pricing density resulting from dynamic hedging of options and the flash crash of May 2010.
Rare Macroeconomic Disasters
Authors: Barro Robert J. , Ursúa José F.
Published: June 2012

The potential for rare macroeconomic disasters may explain an array of asset-pricing puzzles. Our empirical studies of these extreme events rely on long-term data now covering 28 countries for consumption and 40 for GDP. A baseline model calibrated with observed peak-to-trough disaster sizes accords with the average equity premium with a reasonable coefficient of relative risk aversion. High stock-price volatility can be explained by incorporating time-varying long-run growth rates and disaster probabilities. Business-cycle models with shocks to disaster probability have implications for the cyclical behavior of asset returns and corporate leverage, and international versions may explain the uncovered-interest-parity puzzle. Richer models of disaster dynamics allow for transitions between normalcy and disaster, bring in postcrisis recoveries, and use the full time series on consumption. Potential future research includes applications to long-term economic growth and environmental economics, and the use of stock-index options prices and other variables to gauge time-varying disaster probabilities.
Saving Money or Just Saving Lives? Improving the Productivity of US Health Care Spending
Authors: Baicker Katherine , Chandra Amitabh , Skinner Jonathan S.
Published: June 2012

There is growing concern over the rising share of the US economy devoted to health care spending. Fueled in part by demographic transitions, unchecked increases in entitlement spending will necessitate some combination of substantial tax increases, elimination of other public spending, or unsustainable public debt. This massive increase in health spending might be warranted if each dollar devoted to the health care sector yielded real health benefits, but this does not seem to be the case. Although we have seen remarkable gains in life expectancy and functioning over the past several decades, there is substantial variation in the health benefits associated with different types of spending. Some treatments, such as aspirin, beta blockers, and flu shots, produce a large health benefit per dollar spent. Other more expensive treatments, such as stents for cardiovascular disease, are high value for some patients but poor value for others. Finally, a large and expanding set of treatments, such as proton-beam therapy or robotic surgery, contributes to rapid increases in spending despite questionable health benefits. Moving resources toward more productive uses requires encouraging providers to deliver and patients to consume high-value care, a daunting task in the current political landscape. But widespread inefficiency also offers hope: Given the current distribution of resources in the US health care system, there is tremendous potential to improve the productivity of health care spending and the fiscal health of the United States.
International Comparisons in Health Economics: Evidence from Aging Studies
Authors: Banks James , Smith James P.
Published: June 2012

We provide an overview of the growing literature that uses microlevel data from multiple countries to investigate health outcomes, and their link to socioeconomic factors, at older ages. Because the data are at a comparatively young stage, much of the analysis is at an early stage and limited to a handful of countries, with analysis for the United States and England being the most common. What is immediately apparent as we get better measures is that, between countries, health differences amongst those at older ages are real and large. Countries are ranked differently according to whether one considers life expectancy, prevalence, or the incidence of a specific condition. Moreover, the magnitude of international disparities may vary according to whether measures utilize doctor-diagnosed conditions or biomarker-based indicators of disease and poor health. But one key finding emerges—the United States ranks poorly on all indicators, with the exception of self-reported subjective health status.
Probability and Risk: Foundations and Economic Implications of Probability-Dependent Risk Preferences
Authors: Fehr-Duda Helga , Epper Thomas
Published: June 2012

A large body of evidence has documented that risk preferences depend nonlinearly on outcome probabilities. We discuss the foundations and economic consequences of probability-dependent risk preferences and offer a practitioner's guide to understanding and modeling probability dependence. We argue that probability dependence provides a unifying framework for explaining many real-world phenomena, such as the equity premium puzzle, the long-shot bias in betting markets, and households' underdiversification and their willingness to buy small-scale insurance at exorbitant prices. Recent findings indicate that probability dependence is not just a feature of laboratory data, but is indeed manifest in financial, insurance, and betting markets. The neglect of probability dependence may prevent researchers from understanding and predicting important phenomena.
Paul Samuelson's Legacy
Authors: Dixit Avinash
Published: June 2012

Paul Samuelson is probably the most important economist of the second half of the twentieth century. His research publications; his introductory textbook; his articles on topical questions of economic policy; and his interactions with numerous students, colleagues, policy makers, and the wider public have all contributed to fundamental changes in economics as a science and as a profession. This article attempts to give a brief overview of his career spanning eight decades and to recapitulate and celebrate his legacy.