bluuebunny/crossref_metadata_2025 huggingface dataset:
Theory of spin states in coupled quantum dots
Authors: Ponomarev I. V. , Scheibner M. , Stinaff E. A. , Bracker A. S. , Doty M. F. , Badescu S. C. , Ware M. E. , Korenev V. L. , Reinecke T. L. , Gammon D.
Published: October 2006

The coherent quantum coupling of carriers in vertically stacked asymmetric pairs of quantum dots in applied electric fields manifests itself in rich photoluminescence spectral patterns of level crossings and anticrossings. These patterns arise from configurations of charges and spins in optically excited coupled quantum dots. We present a theoretical model that provides a useful picture of these optical properties including spin structure in terms of a minimal number of physical parameters. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Size‐dependence of anisotropic exchange interaction in InAs/GaAs quantum dots
Authors: Seguin R. , Rodt S. , Schliwa A. , Pötschke K. , Pohl U. W. , Bimberg D.
Published: October 2006

A comprehensive study of the exchange interaction between charge carriers in self‐organized InAs/GaAs quantum dots is presented. Single quantum‐dot cathodoluminescence spectra of quantum dots of different sizes are analyzed. Special attention is paid to the energetic structure of the charged excited exciton (hot trion). A varying degree of intermixing within the hot trion states leads to varying degrees of polarization of the corresponding emission lines. The emission characteristics change from circularly polarized for small quantum dots to elliptically polarized for large quantum dots. The findings are explained by a change of magnitude of the anisotropic exchange interaction and compared to the related effect of fine‐structure splitting in the neutral exciton and biexciton emission. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Entangled photon pairs from radiative cascades in semiconductor quantum dots
Authors: Akopian N. , Lindner N. H. , Poem E. , Berlatzky Y. , Avron J. , Gershoni D. , Gerardot B. D. , Petroff P. M.
Published: October 2006

Entangled photon pairs are emitted from a biexciton decay cascade of single quantum dots when spectral filtering is applied. We show this by experimentally measuring the density matrix of the polarization state of the photon pair emitted from a continuously pumped quantum dot. The matrix clearly satisfies the Peres criterion for entanglement. By applying in addition a temporal window, the quantum dot becomes an entangled light source. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Richard E. Smalley (6 June 1943–28 October 2005)
Authors: Weisman Bruce
Published: October 2006

The international scientific community suffered a great loss with the death of Richard Errett (Rick) Smalley at age 62 following a 6‐year battle against cancer. Throughout his career, Rick had a profound influence through his pioneering research in chemistry and nanoscience, his mentorship of young scientists, and his advocacy for the role of science in solving major societal problems.

As a postdoctoral fellow working with Donald Levy and Lennard Wharton at the University of Chicago, Rick spearheaded the invention of supersonic jet spectroscopy. This powerful method cools gas phase molecules nearly to absolute zero, enormously simplifying many complex and otherwise uninterpretable spectra. Thirty years later, supersonic jet spectroscopy remains a vital tool in chemical physics.

Rick Smalley came to Rice University in Houston, Texas in 1976 to accept his first and only faculty appointment. He and his students quickly built an advanced apparatus for supersonic jet spectroscopy and made important contributions to molecular physics. Rick then invented a device to laser‐vaporize high melting materials into small molecular clusters. By spectroscopically probing these novel species, he pioneered another new field: the study of small metal and semiconductor clusters. Rick, Harry Kroto and Robert Curl were investigating carbon clusters in 1985 when they made their famous discovery of the fullerenes, for which they shared the 1996 Nobel Prize in Chemistry. To date, tens of thousands of scientific papers have been published on fullerenes.

In the early 1990's, Rick Smalley turned his attention to the new field of carbon nanotubes. His group made many landmark discoveries and invented nanotube growth methods that supplied samples for researchers around the world. Most recently, Rick expanded his horizons to seek solutions to the immense problem of global energy needs. He helped shape national and international research priorities, including the U.S. National Nanotechnology Initiative. Rick was a visionary and passionate believer in the power of science and technology to solve great problems. He advised students: “Be a scientist and save the world.”

Rick Smalley had great personal charm and charisma. He loved to teach and inspire his students, some of whom described him as “Moses‐like”. He was fearless not only in abandoning the comforts of a successful research program to leap into promising but uncertain new fields, but also in battling his fatal disease while working intensely until the very end of his life. He was devoted to and is survived by his wife Deborah and two sons, Chad and Preston.

Rick Smalley's untimely death is a loss not only to his family, friends, students, colleagues, and collaborators, but to the worldwide communities that he led and served. He will be deeply missed and long remembered. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A diagnostic environment for automaton networks
Authors: Cerutti S. , Lamperti G. , Scaroni M. , Zanella M. , Zanni D.
Published: October 2006

Automated diagnosis of communicating‐automaton networks (CANs) is a complex task, which is typically faced by model‐based reasoning, where the behavior of the network is reconstructed based on its observation. This task may take advantage of knowledge‐compilation techniques, where a large amount of reasoning is anticipated off‐line (when the diagnostic process is not active), by simulating the behavior of the network and by constructing suitable data structures embedding diagnostic information. This (general‐purpose) compiled knowledge is exploited on‐line (when the diagnostic process becomes active), so as to generate the solution to the problem. Additional reusable (special‐purpose) compiled knowledge is generated on‐line when solving new problems. A software environment for the diagnosis of CANs has been developed in the C programming language with the support of the PostgreSQL relational database management system, under the Linux operating system. It supports the modeling and preprocessing of CANs as well as the solution of diagnostic problems, including on‐line knowledge compilation. The environment has been tested through a variety of experiments. Results are encouraging and provide a valuable feedback for further work. Copyright © 2006 John Wiley & Sons, Ltd.
Sequential changes in uterine artery blood flow pattern between the first and second trimesters of gestation in relation to pregnancy outcome
Authors: Gómez O. , Figueras F. , Martínez J. M. , del Río M. , Palacio M. , Eixarch E. , Puerto B. , Coll O. , Cararach V. , Vanrell J. A.
Published: October 2006

Objective

To describe sequential changes in uterine artery waveform between the first and second trimesters of gestation and to analyze their association with the subsequent risk of hypertensive disorders and fetal growth restriction (IUGR).

Methods

Sequential uterine artery Doppler recordings were obtained in a final cohort of 870 singleton pregnancies over two gestational age intervals: 11–14 weeks and 19–22 weeks. The left and right uterine arteries were examined by color and pulsed Doppler and the mean pulsatility index (PI) as well as the presence of a bilateral protodiastolic notch were recorded during both intervals. Pregnancies were followed for occurrence of hypertensive disorders and IUGR.

Results

Mean uterine artery PI showed a significant linear decrease within each of the two intervals considered, while the prevalence of a bilateral notch showed decreasing values only throughout 11–14 weeks of gestation. Sixty‐four (7.3%) pregnancies developed a hypertensive disorder and/or IUGR, including three (0.34%) cases of gestational hypertension, 24 cases of pre‐eclampsia (2.75%) and 37 (4.25%) of IUGR. Compared with pregnancies with a normal outcome, complicated pregnancies showed a significantly higher prevalence of a bilateral notch and a higher mean PI in each of the two intervals studied. Compared with normal pregnancies, complicated pregnancies had a significantly higher persistence of a bilateral notch (30% vs. 8%), a higher proportion of women with an abnormal first‐trimester uterine artery PI shifting to normal in the second trimester (14% vs. 4%) and a higher incidence of a normal first‐trimester mean PI that shifted to abnormal in the second trimester (13% vs. 4%). Persistence of an abnormal mean PI from the first to the second trimester identified the group with the greatest risk for adverse perinatal outcome (OR, 10.7; 95% CI, 3.7–30.9). In addition, women in whom the uterine artery mean PI shifted from abnormal to normal between the two trimesters and women in whom the reverse shift occurred showed a similar intermediate risk (OR, 5; 95% CI, 2.1–10.6), comparable to that in women with persistence of a bilateral notch (OR, 5.6; 95% CI, 2.9–10.7).

Conclusions

The sequence of changes in uterine flow between the first and second trimesters correlates with the subsequent development of hypertensive disorders and IUGR. Women with a persistent abnormal mean PI represent the group with the greatest risk for adverse perinatal outcome. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
SK3 Trafficking in Hippocampal Cells: The Role of Different Molecular Domains
Authors: Decimo Ilaria , Roncarati Renza , Grasso Silvia , Clemens Marcel , Chiamulera Christian , Fumagalli Guido
Published: October 2006

The regulative steps that control trafficking of ion channels are fundamental determinants of their qualitative and quantitative expression on the cell membrane. In this work the trafficking of the small conductance calcium-activated potassium channel, SK3 was studied in neurons in order to identify relevant molecular domains involved in this process. Hippocampal cell cultures were transfected with fusion proteins of green fluorescent protein (GFP) and different SK3 subunit truncations. The differential distribution of the mutants was analyzed by confocal microscopy and compared to the localization of the control fusion protein with full length SK3. The transport of chimeric proteins was quantified from fluorescence images by developing a morphometric analytical method. We found that the full length SK3 was distributed in cell body, axon and dendrites, whereas the deleted forms GFPΔ578–736 (deletion of the entire C-terminal domain), GFPΔCaMBD (deletion of the calmodulin-binding site) and GFPΔN (deletion of the N-terminal domain) were not transported into cell processes but accumulated in the cell body. The GFPΔ640–736 (deletion of the distal C-terminal domain) showed a distribution similar to control. The quantification and statistical analysis confirmed the differences in distribution across the three groups. In conclusion, the current work provides evidence for a fundamental role of the N-terminal domain and the calmodulin binding domain in SK3 trafficking in neurons.
Litigation in otolaryngology – trends and recommendations
Authors: Savage J R , Weiner G M
Published: October 2006

Background: Seeking to identify where litigious claims against otolaryngologists are targeted (i.e. areas of highest risk) within the NHS and private sector would have positive implications in risk management and limiting the amount of litigation against otolaryngologists.

Method: The National Health Service Litigation Authority (NHSLA) and Medical Defence Union (MDU) were contacted and anonymous data obtained on claims within ENT.

Results: 887 claims were notified – 457 NHSLA and 430 MDU. The commonest claim in both groups was failure or delay in diagnosis (12 per cent NHSLA, 23 per cent MDU). The other commonest claims were all related to complications (nerve damage 10 per cent, deafness 8 per cent and dental damage 5 per cent). Dissatisfaction with results was 8 per cent total and, within the private sector, was almost exclusively in rhinology.

Conclusions: This study once again emphasizes the need for thorough clinical assessment, record keeping and good communication with patients. Recognising these areas of highest risk may limit future claims.
Cochlear implants: informing commissioning decisions, based on need
Authors: Taylor F , Hine C
Published: October 2006

Cochlear implantation is a high cost, low volume intervention which is provided to adults and children with profound hearing impairment. Demand is increasing in the UK as a result of improved technology, changes in intervention criteria and the national newborn hearing screening programme. In order to inform commissioning policy for cochlear implantation in five English primary care trusts, we reviewed the evidence and assessed the complexities of developing needs and of service provision assessment and planning. Our results indicated that the current level of provision was well below what would be expected if the majority of people meeting current criteria were given a cochlear implant. Gaps between the clinical intervention thresholds and the level of service commissioned have widened. Long-term cost effectiveness and incidence studies are needed to assess cochlear implantation in the light of these lower clinical intervention thresholds.
From Fome Zero to Bolsa Família: Social Policies and Poverty Alleviation under Lula
Authors: HALL ANTHONY
Published: October 2006

Under the administrations of Fernando Henrique Cardoso (1995–2002) and especially President Lula (2003–), conditional cash transfer (CCT) programmes have become adopted as mainstream social policy in Brazil. This follows a marked trend since the 1990s in Latin America towards the setting up of targeted safety nets to alleviate poverty. Lula consolidated and expanded CCTs, firstly under Fome Zero and later Bolsa Família, now the largest such scheme in the world. Its four sub-programmes (educational stipends to boost school attendance, maternal nutrition, food supplements and a domestic gas subsidy) benefit some 30 million of Brazil's poorest people, with a target of 44 million by 2006. Since 2003, spending on Bolsa Família has risen significantly to consume over one-third of the social assistance budget for the poorest sectors and it remained a flagship policy in the run-up to the presidential elections of October 2006. Although coverage of Bolsa Família is impressive, however, systematic evaluation of its social and economic impacts is still lacking. Evidence from other CCT programmes in Latin America suggests that positive results may be achieved in terms of meeting some immediate needs of the poor. However, there have been many implementation problems. These include poor beneficiary targeting, lack of inter-ministerial coordination, inadequate monitoring, clientelism, weak accountability and alleged political bias. Given the heightened profile of cash transfers in Brazil's social policy agenda, key questions need to be asked. These concern, firstly, the extent to which Bolsa Família does indeed contribute to poverty alleviation; and secondly, whether it creates greater dependence of the poor on government hand-outs and political patronage at the expense of long-term social investment for development.
Grounding Global Justice: International Networks and Domestic Human Rights Accountability in Chile and El Salvador
Authors: COLLINS CATH
Published: October 2006

The UK detention of former Chilean dictator Augusto Pinochet in 1998 was hailed at the time as an unprecedented demonstration of the possible efficacy of ‘global civil society’ networks in holding former heads of state to account for crimes against humanity. This article nonetheless questions the concept, as well as the practical efficacy, of globalised civil society action or ‘human rights lawyering’ as a trigger for the prosecution of past human rights violations. Based on extensive field research, the article argues that domestic factors, including domestic actor pressure and national judicial change, have proved more significant than international law or international activism in recent re-irruptions of the human rights accountability issue in Latin America's Southern Cone. The case of El Salvador, meanwhile, shows that transnational initiatives, while occasionally successful in their own right, have not been able to interrupt or foreshorten domestic post-transitional trajectories to the extent of independently creating favourable accountability conditions.
An ‘ideal bank of issue’: the Banque Nationale de Belgique as a model for the Bank of Japan
Authors: SCHILTZ MICHAEL
Published: October 2006

It is established historical knowledge that the Bank of Japan (1882) was modelled upon the Banque Nationale de Belgique (1850). In this article, I point out how Japan's recurrent frustration with foreign dependence nurtured a social Darwinist view of international politics and finance: Japan's capability to survive in the world was believed to be dependent on its capability to assimilate foreign knowledge and institutions. In the field of finance, Matsukata Masayoshi, Japan's most enlightened financial policy maker at the time, turned to Belgium. I explain that Matsukata was dedicated to the emulation of Belgium's financial infrastructure, in which several public institutions would each be responsible for a specific area of the credit system. I indicate how efforts to adopt Belgian institutions and banking ideas proceeded meticuluously; yet, in the end, Japanese and Belgian finance developed along quite distinct pathways.
Debating sovereign bankruptcy: postrevolutionary Mexico, 1919–1931
Authors: ADAMSON MICHAEL R.
Published: October 2006

This article assesses the extent to which bankers approached sovereign debt defaults during the interwar period according to norms established during the nineteenth century. Bankers treated postrevolutionary Mexico as a hybrid, that is, as a case of both developmental and revenue default, in Fishlow's taxonomy, in the interest of protecting the rights of bondholders generally. Their approach led them to reject the argument of US ambassador to Mexico (and former Morgan partner), Dwight W. Morrow, that a government could be financially insolvent. Bankers acted similarly during the debt crisis of the 1980s.
Coastal upwelling in the East China Sea in winter
Authors: Qiao Fangli , Yang Yongzeng , Lü Xingang , Xia Changshui , Chen Xianyao , Wang Baodong , Yuan Yeli
Published: October 2006

The dynamic mechanisms of the upwelling off the East China Sea (ECS) coast in wintertime are studied. First, the upwelling signals off the ECS coast are identified by the observed temperature, salinity, nutrients, and dissolved oxygen data obtained during the cruises in January 1999. The MASNUM wave‐tide‐circulation coupled model is then employed to simulate the hydrography of the ECS. Comparisons between the simulations and observations show that the model performance is satisfactory. On the basis of successful simulation, four numerical experiments are conducted to investigate the upwelling mechanisms. The results suggest that the density (or salinity) front, which separates the inshore Low Salinity Coastal Water and the offshore Taiwan Warm Current (TWC), is the primary inducement for the upwelling. Owing to strong density gradient, the baroclinic pressure gradient force (PGF) is quite large near the frontal zone, and this PGF elicits an upwelling branch along the topography slope. Wind, TWC, and tide affect the density front in extension and intensity, thus exerting subsidiary influences on the upwelling. According to Ekman's theory, the northerly monsoon is downwelling favorable. However, the net effects of wind on the upwelling off the ECS coast in winter are positive because it drives the Changjiang River Diluted Water (CDW) flowing southward and forms the density front. Similarly, the resultant effects of TWC on the upwelling are negative for obstructing the pathway of CDW. Tide contributes to the upwelling because tidal mixing facilitates the expansion of CDW.
Atmospheric chemistry of a 33–34 hour old volcanic cloud from Hekla Volcano (Iceland): Insights from direct sampling and the application of chemical box modeling
Authors: Rose William I. , Millard Genevieve A. , Mather Tamsin A. , Hunton Donald E. , Anderson Bruce , Oppenheimer Clive , Thornton Brett F. , Gerlach Terrence M. , Viggiano Albert A. , Kondo Yutaka , Miller Thomas M. , Ballenthin John O.
Published: October 2006

On 28 February 2000, a volcanic cloud from Hekla volcano, Iceland, was serendipitously sampled by a DC‐8 research aircraft during the SAGE III Ozone Loss and Validation Experiment (SOLVE I). It was encountered at night at 10.4 km above sea level (in the lower stratosphere) and 33–34 hours after emission. The cloud is readily identified by abundant SO2 (≤1 ppmv), HCl (≤70 ppbv), HF (≤60 ppbv), and particles (which may have included fine silicate ash). We compare observed and modeled cloud compositions to understand its chemical evolution. Abundances of sulfur and halogen species indicate some oxidation of sulfur gases but limited scavenging and removal of halides. Chemical modeling suggests that cloud concentrations of water vapor and nitric acid promoted polar stratospheric cloud (PSC) formation at 201–203 K, yielding ice, nitric acid trihydrate (NAT), sulfuric acid tetrahydrate (SAT), and liquid ternary solution H2SO4/H2O/HNO3 (STS) particles. We show that these volcanically induced PSCs, especially the ice and NAT particles, activated volcanogenic halogens in the cloud producing >2 ppbv ClOx. This would have destroyed ozone during an earlier period of daylight, consistent with the very low levels of ozone observed. This combination of volcanogenic PSCs and chlorine destroyed ozone at much faster rates than other PSCs that Arctic winter. Elevated levels of HNO3 and NOy in the cloud can be explained by atmospheric nitrogen fixation in the eruption column due to high temperatures and/or volcanic lightning. However, observed elevated levels of HOx remain unexplained given that the cloud was sampled at night.
Integrated processes analysis and systematic meteorological classification of ozone episodes in Hong Kong
Authors: Huang Jian‐Ping , Fung Jimmy C. H. , Lau Alexis K. H.
Published: October 2006

We have conducted a systematic and comprehensive survey of 54 O3 episodes that occurred over Hong Kong during 2000–2004 using the Pollutants in the Atmosphere and their Transport over Hong Kong (PATH) model system. We identify the relative contributions of regional transport and local chemical production for these O3 episodes. Two regimes with different relative regional or local contributions are identified. Subsequently, meteorological analyses are used to help identify the synoptic patterns associated with the O3 episodes of these two regimes. In particular, we find that the O3 episodes are dominated by regional transport when a tropical cyclone/typhoon is located over the northwestern Pacific or the South China Sea to the east or southeast (a “C” pattern), when an anticyclone (i.e., a local high‐pressure system) appears over mainland China to the north (“A”), or both (“AC”). On the other hand, local chemical production dominates when a trough is situated to the east over the South China Sea (“T”). Strongest regional transport is associated with the “C” or “AC” synoptic patterns. These results are likely related to the stronger horizontal advection of O3 under the “C,” “A,” or “AC” patterns (as compared with “T”), as well as the stronger production of O3 in the Pearl River Delta region under clear sunny skies at the periphery of a tropical cyclone/typhoon (“C”) and/or under a high‐pressure system (“A”). These four characteristic synoptic patterns, namely, “C,” “A,” “AC,” and “T,” account for 33%, 17%, 28%, and 22% of the 54 episodes, respectively, between 2000 and 2004. Finally, back trajectory analyses also show that the lower regional contributions in the trough cases (“T”) are related to their airflow pathways not passing through the O3‐rich Pearl River Estuary. This study also shows that a systematic and comprehensive application of integrated process analysis can be used to identify and summarize the salient features (weather patterns in this case) of specific type of air quality events.
Displacement field and slip distribution of the 2005 Kashmir earthquake from SAR imagery
Authors: Pathier E. , Fielding E. J. , Wright T. J. , Walker R. , Parsons B. E. , Hensley S.
Published: October 2006

The 8th October 2005 Kashmir Earthquake Mw 7.6 involved primarily thrust motion on a NE‐dipping fault. Sub‐pixel correlation of ENVISAT SAR images gives the location of the 80 km‐long fault trace (within 300–800 m) and a 3D surface displacement field with a sub‐metric accuracy covering the whole epicentral area. The slip distribution inverted using elastic dislocation models indicates that slip occurs mainly in the upper 10 km, between the cities of Muzaffarabad and Balakot. The rupture reached the surface in several places. In the hanging wall, horizontal motions show rotation from pure thrust to oblique right‐lateral motion that are not observed in the footwall. A segmentation of the fault near Muzaffarabad is also suggested. North of the city of Balakot, slip decreases dramatically, but a diffuse zone of mainly vertical surface displacements, which could be post‐seismic, exists further north, where most of the aftershocks occur, aligned along the NW‐SE Indus‐Kohistan Seismic Zone.
Amplified erosion above waterfalls and oversteepened bedrock reaches
Authors: Haviv I. , Enzel Y. , Whipple K. X. , Zilberman E. , Stone J. , Matmon A. , Fifield L. K.
Published: October 2006

None of the conventional bedrock erosion laws can predict incision immediately upslope of a waterfall lip where the flow is accelerating toward a freefall. Considering the expected increase in flow velocity and shear stress at the lip of a waterfall, we determine erosion amplification at a waterfall lip as , where E() is the erosion rate at the upstream end of the flow acceleration zone above a waterfall, Fr is the Froude number at this setting, and n ranges between 0.5–1.7. This amplification expression suggests that erosion at the lip could be as much as 2–5 times higher relative to erosion at a normal setting with identical hydraulic geometry. Utilizing this erosion amplification expression in numerical simulations, we demonstrate its impact on reach‐scale morphology above waterfalls. Amplified erosion at the lip of a waterfall can trigger the formation of an oversteepened reach whose length is longer than the flow acceleration zone, provided incision wave velocity (Vi) at the upstream edge of the flow acceleration zone is higher than the retreat velocity of the waterfall face. Such an oversteepened reach is expected to be more pronounced when Vi increases with increasing slope. The simulations also suggest that oversteepening can eventually lead to steady state gradients adjacent to a waterfall lip provided Vi decreases with increasing slope. Flow acceleration above waterfalls can thus account, at least partially, for prevalent oversteepened bedrock reaches above waterfalls. Using the cosmogenic isotope Cl‐36, we demonstrate that incision wave velocity upstream of a waterfall at the Dead Sea western escarpment is probably high enough for freefall‐induced oversteepening to be feasible.
Positive inotropic effects of carbon monoxide‐releasing molecules (CO‐RMs) in the isolated perfused rat heart
Authors: Musameh M D , Fuller B J , Mann B E , Green C J , Motterlini R
Published: October 2006

Background and purpose:

Carbon monoxide (CO) generated by the enzyme haeme oxygenase‐1 (HO‐1) during the breakdown of haeme is known to mediate a number of biological effects. Here, we investigated whether CO liberated from two water soluble carbon monoxide‐releasing molecules (CO‐RMs) exerts inotropic effects on the myocardium.

Experimental approach:

Rat isolated hearts perfused either at constant flow or constant pressure were used to test the effect of CO‐RMs.

Key results:

CORM‐3, a fast CO releaser, produced a direct positive inotropic effect when cumulative doses (3, 10 and 30 μg min−1) or a single dose (5 μM) were infused at either constant coronary pressure (CCP) or constant coronary flow (CCF). The inotropic effect mediated by CORM‐3 was abolished by blockade of soluble guanylate cyclase or Na+/H+ exchanger, but not by inhibitors of L‐type Ca2+ channels and protein kinase C. CORM‐3 also caused a slight reduction in heart rate but did not alter coronary flow. In contrast, the slow CO releaser CORM‐A1 produced significant coronary vasodilatation when given at the highest concentration (30 μg min−1) but exerted no effect on myocardial contractility or heart rate.

Conclusion and implications:

A rapid CO release from CORM‐3 exerts a direct positive inotropic effect on rat isolated perfused hearts, whereas CO slowly released by CORM‐A1 had no effect on myocardial contractility but caused significant coronary vasodilatation. Both cGMP and Na+/H+ exchange appear to be involved in this effect but further work is needed to determine the relative contribution of each pathway in CO‐mediated inotropic effect.

British Journal of Pharmacology (2006) 149, 1104–1112. doi:10.1038/sj.bjp.0706939
Tactile guidance of prey capture in Etruscan shrews
Authors: Anjum Farzana , Turni Hendrik , Mulder Paul G. H. , van der Burg Johannes , Brecht Michael
Published: October 2006

Whereas visuomotor behaviors and visual object recognition have been studied in detail, we know relatively little about tactile object representations. We investigate a new model system for the tactile guidance of behavior, namely prey (cricket) capture by one of the smallest mammals, the Etruscan shrew,
Suncus etruscus
. Because of their high metabolic rate and nocturnal lifestyle, Etruscan shrews are forced to detect, overwhelm, and kill prey in large numbers in darkness. Crickets are exquisitely mechanosensitive, fast-moving prey, almost as big as the shrew itself. Shrews succeed in hunting by lateralized, precise, and fast attacks. Removal experiments demonstrate that both macrovibrissae and microvibrissae are required for prey capture, with the macrovibrissae being involved in attack targeting. Experiments with artificial prey replica show that tactile shape cues are both necessary and sufficient for evoking attacks. Prey representations are motion- and size-invariant. Shrews distinguish and memorize prey features. Corrective maneuvers and cricket shape manipulation experiments indicate that shrew behavior is guided by Gestalt-like prey descriptions. Thus, tactile object recognition in Etruscan shrews shares characteristics of human visual object recognition, but it proceeds faster and occurs in a 20,000-times-smaller brain.
Different modes of SecY–SecA interactions revealed by site-directed
in vivo
photo-cross-linking
Authors: Mori Hiroyuki , Ito Koreaki
Published: October 2006

While the SecA ATPase drives protein translocation across the bacterial cytoplasmic membrane by interacting with the SecYEG translocon, molecular details of SecA–SecY interaction remain poorly understood. Here, we studied SecY–SecA interaction by using an
in vivo
site-directed cross-linking technique developed by Schultz and coworkers [Chin, J. W., Martin, A. B., King, D. S., Wang, L., Schultz, P. G. (2002)
Proc. Natl. Acad. Sci. USA
99:11020–11024 and Chin, J. W., Schultz, P. G. (2002)
ChemBioChem
3:1135–1137]. Benzoyl-phenylalanine introduced into specific SecY positions at the second, fourth, fifth, and sixth cytoplasmic domains allowed UV cross-linking with SecA. Cross-linked products exhibited two distinct electrophoretic mobilities. SecA cross-linking at the most C-terminal cytoplasmic region (C6) was specifically enhanced in the presence of NaN
3
, which arrests the ATPase cycle, and this enhancement was canceled by cis placement of some
secY
mutations that affect SecY–SecA cooperation.
In vitro
experiments showed directly that SecA approaches C6 when it is engaging in ATP-dependent preprotein translocation. On the basis of these findings, we propose that the C6 tail of SecY interacts with the working form of SecA, whereas C4–C5 loops may offer constitutive SecA-binding sites.
Pheromone reception in fruit flies expressing a moth's odorant receptor
Authors: Syed Zainulabeuddin , Ishida Yuko , Taylor Katherine , Kimbrell Deborah A. , Leal Walter S.
Published: October 2006

We have expressed a male-specific, pheromone-sensitive odorant receptor (OR),
BmorOR1
, from the silkworm moth
Bombyx mori
in an “empty neuron” housed in the ab3 sensilla of a
Drosophila
Δ
halo
mutant. Single-sensillum recordings showed that the
BmorOR1
-expressing neurons in the transgenic flies responded to the
B. mori
pheromone bombykol, albeit with low sensitivity. These transgenic flies responded to lower doses of bombykol in an altered stimulation method with direct delivery of pheromone into the sensillum milieu. We also expressed a
B. mori
pheromone-binding protein,
BmorPBP
, in the
BmorOR1
-expressing ab3 sensilla. Despite the low levels of
BmorPBP
expression, flies carrying both
BmorOR1
and
BmorPBP
showed significantly higher electrophysiological responses than
BmorOR1
flies. Both types of
BmorOR1
-expressing flies responded to bombykol, and to a lesser extent to a second compound, bombykal, even without the addition of organic solvents to the recording electrode buffer. When the semiochemicals were delivered by the conventional puffing of stimulus on the antennae, the receptor responded to bombykol but not to bombykal. The onset of response was remarkably slow, and neural activity extended for an unusually long time (>1 min) after the end of stimulus delivery. We hypothesize that
BmorOR1
-expressing ab3 sensilla lack a pheromone-degrading enzyme to rapidly inactivate bombykol and terminate the signal. We also found an endogenous receptor in one of the sensillum types on
Drosophila
antenna that responds to bombykol and bombykal with sensitivity comparable to the pheromone-detecting sensilla on
B. mori
male antennae.
The p110α isoform of PI3K is essential for proper growth factor signaling and oncogenic transformation
Authors: Zhao Jean J. , Cheng Hailing , Jia Shidong , Wang Li , Gjoerup Ole V. , Mikami Aki , Roberts Thomas M.
Published: October 2006

Growth factor signaling is mediated through Class IA phosphatidylinositol 3-kinases (PI3Ks). Among this class of enzymes, only p110α, encoded by the
PIK3CA
gene, has been found to be mutant in human cancers. To determine the specific functions of p110α, we generated mice carrying a conditionally targeted allele of the
PIK3CA
gene. Here, we report that
PIK3CA
-knockout mouse embryonic fibroblasts are deficient in cellular signaling in response to various growth factors, unable to differentiate into adipocytes, and resistant to oncogenic transformation induced by a variety of oncogenic receptor tyrosine kinases, indicating a fundamental role for p110α in these biological processes.
Defective mitochondrial peroxiredoxin-3 results in sensitivity to oxidative stress in Fanconi anemia
Authors: Mukhopadhyay Sudit S. , Leung Kathryn S. , Hicks M. John , Hastings Philip J. , Youssoufian Hagop , Plon Sharon E.
Published: October 2006

Cells from patients with Fanconi anemia (FA), an inherited disorder that includes bone marrow failure and cancer predisposition, have increased sensitivity to oxidative stress through an unknown mechanism. We demonstrate that the FA group G (FANCG) protein is found in mitochondria. Wild-type but not G546R mutant FANCG physically interacts with the mitochondrial peroxidase peroxiredoxin-3 (PRDX3). PRDX3 is deregulated in FA cells, including cleavage by a calpainlike cysteine protease and mislocalization. FA-G cells demonstrate distorted mitochondrial structures, and mitochondrial extracts have a sevenfold decrease in thioredoxin-dependent peroxidase activity. Transient overexpression of PRDX3 suppresses the sensitivity of FA-G cells to H2O2, and decreased PRDX3 expression increases sensitivity to mitomycin C. Cells from the FA-A and -C subtypes also have PRDX3 cleavage and decreased peroxidase activity. This study demonstrates a role for the FA proteins in mitochondria witsh sensitivity to oxidative stress resulting from diminished peroxidase activity. These defects may lead to apoptosis and the accumulation of oxidative DNA damage in bone marrow precursors.
Signal-dependent splicing of tissue factor pre-mRNA modulates the thrombogenecity of human platelets
Authors: Schwertz Hansjörg , Tolley Neal D. , Foulks Jason M. , Denis Melvin M. , Risenmay Ben W. , Buerke Michael , Tilley Rachel E. , Rondina Matthew T. , Harris Estelle M. , Kraiss Larry W. , Mackman Nigel , Zimmerman Guy A. , Weyrich Andrew S.
Published: October 2006

Tissue factor (TF) is an essential cofactor for the activation of blood coagulation in vivo. We now report that quiescent human platelets express TF pre-mRNA and, in response to activation, splice this intronic-rich message into mature mRNA. Splicing of TF pre-mRNA is associated with increased TF protein expression, procoagulant activity, and accelerated formation of clots. Pre-mRNA splicing is controlled by Cdc2-like kinase (Clk)1, and interruption of Clk1 signaling prevents TF from accumulating in activated platelets. Elevated intravascular TF has been reported in a variety of prothrombotic diseases, but there is debate as to whether anucleate platelets—the key cellular effector of thrombosis—express TF. Our studies demonstrate that human platelets use Clk1-dependent splicing pathways to generate TF protein in response to cellular activation. We propose that platelet-derived TF contributes to the propagation and stabilization of a thrombus.
The effect of sample size and species characteristics on performance of different species distribution modeling methods
Authors: Hernandez Pilar A. , Graham Catherine H. , Master Lawrence L. , Albert Deborah L.
Published: October 2006

Species distribution models should provide conservation practioners with estimates of the spatial distributions of species requiring attention. These species are often rare and have limited known occurrences, posing challenges for creating accurate species distribution models. We tested four modeling methods (Bioclim, Domain, GARP, and Maxent) across 18 species with different levels of ecological specialization using six different sample size treatments and three different evaluation measures. Our assessment revealed that Maxent was the most capable of the four modeling methods in producing useful results with sample sizes as small as 5, 10 and 25 occurrences. The other methods compensated reasonably well (Domain and GARP) to poorly (Bioclim) when presented with datasets of small sample sizes. We show that multiple evaluation measures are necessary to determine accuracy of models produced with presence‐only data. Further, we found that accuracy of models is greater for species with small geographic ranges and limited environmental tolerance, ecological characteristics of many rare species. Our results indicate that reasonable models can be made for some rare species, a result that should encourage conservationists to add distribution modeling to their toolbox.
Factors that contribute to high turnover among residential child care staff
Authors: Colton Matthew , Roberts Susan
Published: October 2006

In this paper we draw on our own empirical research and that of others to consider the factors that contribute to high staff turnover in residential child care. First, we focus on the problem of retaining staff in children’s services. Second, we turn our attention to the factors that contribute to staff turnover in residential care: namely, perceptions of the service; of children and young people; and of human resource issues. Third, we attempt to draw out the implications of high turnover for policy and practice. The negative image of residential care has persisted in the wake of a plethora of abuse scandals. The increasing emotional and behavioural problems presented by the children cared for, and the violence and verbal abuse directed at staff are key retention issues. Moreover, poor conditions of employment contribute to staff perceptions of the work as a short‐term career choice only. The potential means of resolving these problems are explored, and the future research agenda highlighted.
Relationships between microcystins and environmental parameters in 30 subtropical shallow lakes along the Yangtze River, China
Authors: WU S. K. , XIE P. , LIANG G. D. , WANG S. B. , LIANG X. M.
Published: October 2006

1. A survey of 30 subtropical shallow lakes in the middle and lower reaches of the Yangtze River area in China was conducted during July–September in 2003–2004 to study how environmental and biological variables were associated with the concentration of the cyanobacterial toxin microcystin (MC).

2. Mean MC concentration in seasonally river‐connected lakes (SL) was nearly 33 times that in permanently river‐connected lakes (RL), and more than six times that in city lakes (NC) and non‐urban lakes (NE) which were not connected to the Yangtze River. The highest MC (8.574 μg L−1) was detected in Dianshan Lake.

3. MC‐RR and MC‐LR were the primary toxin variants in our data. MC‐RR, MC‐YR and MC‐LR were significantly correlated with Chl a, biomass of cyanobacteria, Microcystis and Anabaena, indicating that microcystins were mainly produced by Microcystis and Anabaena sp. in these lakes.

4. Nonlinear interval maxima regression indicated that the relationships of Secchi depth, total nitrogen (TN) : total phosphorus (TP) and NH with MC were characterised by negative exponential curves. The relationships between MC and TN, TP, NO + NO were fitted well with a unimodal curve.

5. Multivariate analyses by principal component and classifying analysis indicated that MC was mainly affected by Microcystis among the biological factors, and was closely related with temperature among physicochemical factors.
Interleukin‐4 inhibits cyclo‐oxygenase‐2 expression and prostaglandin E2 production by human mature dendritic cells
Authors: Teloni Raffaela , Giannoni Federico , Rossi Paolo , Nisini Roberto , Gagliardi Maria Cristina
Published: October 2006

Interleukin‐4 (IL‐4) is considered the key cytokine for inducing T helper type 2 (Th2) cell differentiation, while interferon‐γ and IL‐12 are pivotal cytokines for Th1 immune responses. Paradoxically, IL‐4 has also been demonstrated to enhance IL‐12 production by dendritic cells, suggesting an IL‐4‐dependent regulatory feedback of the Th1/Th2 system. In addition, prostaglandin E2 (PGE2), a lipid mediator of inflammation, has been implicated in the enhancement of Th2‐type responses acting directly on T and B lymphocytes. PGE2 synthesis is dependent on the serial engagement of various enzymes, among which the inducible cyclo‐oxygenase‐2 (COX‐2) exerts a critical role in monocytes and dendritic cells. In this study we demonstrate that IL‐4 inhibits COX‐2 gene expression and consequently prevents secretion of PGE2 by mature human dendritic cells. We also show that PGE2 does not regulate IL‐12 and IL‐10 production by dendritic cells in an autocrine fashion. Hence, we suggest that IL‐4 may exploit an IL‐12‐independent regulatory feedback of the Th1/Th2 system through PGE2 inhibition.
The influence of pH and digestion with commercial enzymes on calcium adsorption in casabe
Authors: Navas Petra Beatriz , Carrasquero‐Durán Armando
Published: October 2006

The Ca2+ binding capacity of a sample of casabe made from cassava (Manihot esculenta) was evaluated by using adsorption isotherms after a digestion process with commercial enzymes. It was found that enzymatic treatment increased the ability of vegetable material to retain calcium and to release endogenous mineral ions as a consequence of possible modifications to the carbohydrate matrix. Untreated casabe did not release mineral ions. pH also influenced the retention of Ca2+: at pH 4.5 release was the main process but adsorption increases with alkalinity up to pH 8.5. The Ca concentrations at which neither adsorption nor release occurred [Ca2+]e were as follows: 5.2 mm (pH 4.5), 3.5 mm (pH 7.1), and 0.63 mm (pH 8.5). The pH effect was explained by an increase in the density of negatively charged functional groups produced by ionization reactions at pH below the point of zero net charge (pHo) which was evaluated by using the Gouy–Chapman double layer model. Values of pHo were 6.4 for raw material and 4.1 after digestion with enzymes. In both cases, the density of positively charged sites below pHo was much higher that the density of negatively charged sites above pHo.
Diagnostic errors and reflective practice in medicine
Authors: Mamede Sílvia , Schmidt Henk G. , Rikers Remy
Published: October 2006

Background  Adverse effects of medical errors have received increasing attention. Diagnostic errors account for a substantial fraction of all medical errors, and strategies for their prevention have been explored. A crucial requirement for that is better understanding of origins of medical errors. Research on medical expertise may contribute to that as far as it explains reasoning processes involved in clinical judgements. The literature has indicated the capability of critically reflecting upon one’s own practice as a key requirement for developing and maintaining medical expertise throughout life.

Objectives  This article explores potential relationships between reflective practice and diagnostic errors.

Methods  A survey of the medical expertise literature was canducted. Origins of medical errors frequently reported in the literature were explored. The potential relationship between diagnostic errors and the several dimensions of reflective practice in medicine, brought to light by recent research, were theoretically explored.

Results and Dissussion  Uncertainty and fallibility inherent to clinical judgements are discussed. Stages in the diagnostic reasoning process where errors could occur and their potential sources are highlighted, including the role of medical heuristics and biases. The authors discuss the nature of reflective practice in medicine, and explore whether and how the several behaviours and reasoning processes that constitute reflective practice could minimize diagnostic errors. Future directions for further research are discussed. They involve empirical research on the role of reflective practice in improving clinical reasoning and the development of educational strategies to enhancing reflective practice.