bluuebunny/crossref_metadata_2025 huggingface dataset:
Evolution of stratospheric temperature in the 20th century
Authors: Schwarzkopf M. Daniel , Ramaswamy V.
Published: February 2008

We employ a coupled atmosphere‐ocean climate model to investigate the evolution of stratospheric temperatures over the twentieth century, forced by the known anthropogenic and natural forcing agents. In the global, annual‐mean lower‐to‐middle stratosphere (∼20–30 km.), simulations produce a sustained, significant cooling by ∼1920, earlier than in any lower atmospheric region, largely resulting from carbon dioxide increases. After 1979, stratospheric ozone decreases reinforce the cooling. Arctic summer cooling attains significance almost as early as the global, annual‐mean response. Antarctic responses become significant in summer after ∼1940 and in spring after ∼1990 (below ∼21 km.). The correspondence of simulated and observed stratospheric temperature trends after ∼1960 suggests that the model's stratospheric response is reasonably similar to that of the actual climate. We conclude that these model simulations are useful in explaining stratospheric temperature change over the entire 20th century, and potentially provide early indications of the effects of future atmospheric species changes.
Effects of atmospheric vorticity on the seasonal hydrographic cycle over the eastern Siberian shelf
Authors: Dmitrenko Igor A. , Kirillov Sergey A. , Tremblay L. B. , Bauch Dorothea , Makhotin Mikhail
Published: February 2008

The seasonal hydrographic cycle explains about 25–75% of the entire salinity variability spectrum of the Siberian shelf hydrography. Quasi‐decadal variations in the seasonal salinity difference over the Laptev and East Siberian sea shelves derived from continuous summer‐to‐winter historical records from the 1960s–1990s are attributed to atmospheric vorticity quasi‐decadal variations. Summer cyclonic vorticity results in riverine water accumulation on the shelf, increasing the salinity summer‐to‐winter difference. Summer anticyclonic wind pattern enhances fresh water movement from the shelf towards the Arctic Ocean that tends to weaken the seasonal salinity amplitude.
Simulation of Na D emission near Europa during eclipse
Authors: Cassidy T. A. , Johnson R. E. , Geissler P. E. , Leblanc F.
Published: February 2008

The Cassini imaging science subsystem observed Europa in eclipse during Cassini's Jupiter flyby. The disk‐resolved observations revealed a spatially nonuniform emission in the wavelength range of 200–1050 nm (clear filters). By building on observations and simulations of Europa's Na atmosphere and torus we find that electron‐excited Na in Europa's tenuous atmosphere can account for the observed emission if the Na is ejected preferentially from Europa's dark terrain.
Greenway Accessibility and Physical-Activity Behavior
Authors: Coutts Christopher
Published: February 2008

Public health initiatives have made important but relatively modest gains through individual-level and nonecological health-promotion efforts aimed at increasing physical activity. The previously overlooked built environment is now being considered as facilitating or hindering one's ability to be active. The multiuse greenway is an example of a facility that can support physical activity, but its level of use may be influenced by the accessibility characteristics of the areas surrounding the greenway. In this study, an unobtrusive methodology using GPS and GIS technology was employed to test whether two variables used to measure accessibility, proximity (population density) and opportunities (land-use mixture), predicted the use of greenway segments. The results presented here allow us to confirm that smaller walking and bicycling scales of analysis are better predictors of physical-activity behavior. The results also suggest that solely bringing environmental support for physical activity closer to concentrated areas of population does not necessarily equate to more use. It is important that areas with increased population density have correspondingly increased levels of land-use mixture if increasing physical activity is the goal.
Electroactive controlled release thin films
Authors: Wood Kris C. , Zacharia Nicole S. , Schmidt Daniel J. , Wrightman Stefani N. , Andaya Brian J. , Hammond Paula T.
Published: February 2008

We present the fabrication of nanoscale electroactive thin films that can be engineered to undergo remotely controlled dissolution in the presence of a small applied voltage (+1.25 V) to release precise quantities of chemical agents. These films, which are assembled by using a nontoxic, FDA-approved, electroactive material known as Prussian Blue, are stable enough to release a fraction of their contents after the application of a voltage and then to restabilize upon its removal. As a result, it is possible to externally trigger agent release, exert control over the relative quantity of agents released from a film, and release multiple doses from one or more films in a single solution. These electroactive systems may be rapidly and conformally coated onto a wide range of substrates without regard to size, shape, or chemical composition, and as such they may find use in a host of new applications in drug delivery as well as the related fields of tissue engineering, medical diagnostics, and chemical detection.
Insights into bunyavirus architecture from electron cryotomography of Uukuniemi virus
Authors: Överby A. K. , Pettersson R. F. , Grünewald K. , Huiskonen J. T.
Published: February 2008

Bunyaviridae
is a large family of viruses that have gained attention as “emerging viruses” because many members cause serious disease in humans, with an increasing number of outbreaks. These negative-strand RNA viruses possess a membrane envelope covered by glycoproteins. The virions are pleiomorphic and thus have not been amenable to structural characterization using common techniques that involve averaging of electron microscopic images. Here, we determined the three-dimensional structure of a member of the
Bunyaviridae
family by using electron cryotomography. The genome, incorporated as a complex with the nucleoprotein inside the virions, was seen as a thread-like structure partially interacting with the viral membrane. Although no ordered nucleocapsid was observed, lateral interactions between the two membrane glycoproteins determine the structure of the viral particles. In the most regular particles, the glycoprotein protrusions, or “spikes,” were seen to be arranged on an icosahedral lattice, with
T
= 12 triangulation. This arrangement has not yet been proven for a virus. Two distinctly different spike conformations were observed, which were shown to depend on pH. This finding is reminiscent of the fusion proteins of alpha-, flavi-, and influenza viruses, in which conformational changes occur in the low pH of the endosome to facilitate fusion of the viral and host membrane during viral entry.
Reduction of IgG in nonhuman primates by a peptide antagonist of the neonatal Fc receptor FcRn
Authors: Mezo Adam R. , McDonnell Kevin A. , Hehir Cristina A. Tan , Low Susan C. , Palombella Vito J. , Stattel James M. , Kamphaus George D. , Fraley Cara , Zhang Yixia , Dumont Jennifer A. , Bitonti Alan J.
Published: February 2008

The neonatal Fc receptor FcRn provides IgG molecules with their characteristically long half-livesin vivoby protecting them from intracellular catabolism and then returning them to the extracellular space. Other investigators have demonstrated that mice lacking FcRn are protected from induction of various autoimmune diseases, presumably because of the accelerated catabolism of pathogenic IgGs in the animals. Therefore, targeting FcRn with a specific inhibitor may represent a unique approach for the treatment of autoimmune disease or other diseases where the reduction of pathogenic IgG will have a therapeutic benefit. Using phage display peptide libraries, we screened for ligands that bound to human FcRn (hFcRn) and discovered a consensus peptide sequence that binds to hFcRn and inhibits the binding of human IgG (hIgG)in vitro. Chemical optimization of the phage-identified sequences yielded the 26-amino acid peptide dimer SYN1436, which is capable of potentin vitroinhibition of the hIgG–hFcRn interaction. Administration of SYN1436 to mice transgenic for hFcRn induced an increase in the rate of catabolism of hIgG in a dose-dependent manner. Treatment of cynomolgus monkeys with SYN1436 led to a reduction of IgG by up to 80% without reducing serum albumin levels that also binds to FcRn. SYN1436 and related peptides thus represent a previously uncharacterized family of potential therapeutic agents for the treatment of humorally mediated autoimmune and other diseases.
Wound angiogenesis as a function of tissue oxygen tension: A mathematical model
Authors: Schugart Richard C. , Friedman Avner , Zhao Rui , Sen Chandan K.
Published: February 2008

Wound healing represents a well orchestrated reparative response that is induced by injuries. Angiogenesis plays a central role in wound healing. In this work, we sought to develop the first mathematical model directed at addressing the role of tissue oxygen tension on cutaneous wound healing. Key components of the developed model include capillary tips, capillary sprouts, fibroblasts, inflammatory cells, chemoattractants, oxygen, and the extracellular matrix. The model consists of a system of nonlinear partial differential equations describing the interactions in space and time of these variables. The simulated results agree with the reported literature on the biology of wound healing. The proposed model represents a useful tool to analyze strategies for improved healing and generate a hypothesis for experimental testing.
A chemical method for fast and sensitive detection of DNA synthesis
in vivo
Authors: Salic Adrian , Mitchison Timothy J.
Published: February 2008

We have developed a method to detect DNA synthesis in proliferating cells, based on the incorporation of 5-ethynyl-2′-deoxyuridine (EdU) and its subsequent detection by a fluorescent azide through a Cu(I)-catalyzed [3 + 2] cycloaddition reaction (“click” chemistry). Detection of the EdU label is highly sensitive and can be accomplished in minutes. The small size of the fluorescent azides used for detection results in a high degree of specimen penetration, allowing the staining of whole-mount preparations of large tissue and organ explants. In contrast to BrdU, the method does not require sample fixation or DNA denaturation and permits good structural preservation. We demonstrate the use of the method in cultured cells and in the intestine and brain of whole animals.
Identifying the fundamental units of bacterial diversity: A paradigm shift to incorporate ecology into bacterial systematics
Authors: Koeppel Alexander , Perry Elizabeth B. , Sikorski Johannes , Krizanc Danny , Warner Andrew , Ward David M. , Rooney Alejandro P. , Brambilla Evelyne , Connor Nora , Ratcliff Rodney M. , Nevo Eviatar , Cohan Frederick M.
Published: February 2008

The central questions of bacterial ecology and evolution require a method to consistently demarcate, from the vast and diverse set of bacterial cells within a natural community, the groups playing ecologically distinct roles (ecotypes). Because of a lack of theory-based guidelines, current methods in bacterial systematics fail to divide the bacterial domain of life into meaningful units of ecology and evolution. We introduce a sequence-based approach (“ecotype simulation”) to model the evolutionary dynamics of bacterial populations and to identify ecotypes within a natural community, focusing here on two
Bacillus
clades surveyed from the “Evolution Canyons” of Israel. This approach has identified multiple ecotypes within traditional species, with each predicted to be an ecologically distinct lineage; many such ecotypes were confirmed to be ecologically distinct, with specialization to different canyon slopes with different solar exposures. Ecotype simulation provides a long-needed natural foundation for microbial ecology and systematics.
Observation Can Be as Effective as Action in Problem Solving
Authors: Osman Magda
Published: February 2008

This study discusses findings that replicate and extend the original work of , which showed that performance in problem‐solving tasks was more accurate when people were engaged in a non‐specific goal than in a specific goal. The main innovation here was to examine the goal specificity effect under both observation‐based and conventional action‐based learning conditions. The findings show that goal specificity affects the accuracy of problem solving in the same way when the learning stage of the task is observation‐based as when it is action‐based. In addition, the findings show that, when instructions do not promote goal specificity, observation‐based problem solving is as effective as action‐based problem solving.
Lexical Categories at the Edge of the Word
Authors: Onnis Luca , Christiansen Morten H.
Published: February 2008

Language acquisition may be one of the most difficult tasks that children face during development. They have to segment words from fluent speech, figure out the meanings of these words, and discover the syntactic constraints for joining them together into meaningful sentences. Over the past couple of decades, computational modeling has emerged as a new paradigm for gaining insights into the mechanisms by which children may accomplish these feats. Unfortunately, many of these models assume a computational complexity and linguistic knowledge likely to be beyond the abilities of developing young children. This article shows that, using simple statistical procedures, significant correlations exist between the beginnings and endings of a word and its lexical category in English, Dutch, French, and Japanese. Therefore, phonetic information can contribute to individuating higher level structural properties of these languages. This article also presents a simple 2‐layer connectionist model that, once trained with an initial small sample of words labeled for lexical category, can infer the lexical category of a large proportion of novel words using only word‐edge phonological information, namely the first and last phoneme of a word. The results suggest that simple procedures combined with phonetic information perceptually available to children provide solid scaffolding for emerging lexical categories in language development.
Is Structure Dependence an Innate Constraint? New Experimental Evidence From Children's Complex‐Question Production
Authors: Ambridge Ben , Rowland Caroline F. , Pine Julian M.
Published: February 2008

According to , when forming complex yes/no questions, children do not make errors such as Is the boy who smoking is crazy? because they have innate knowledge of structure dependence and so will not move the auxiliary from the relative clause. However, simple recurrent networks are also able to avoid such errors, on the basis of surface distributional properties of the input (; ). Two new elicited production studies revealed that (a) children occasionally produce structure‐dependence errors and (b) the pattern of children's auxiliary‐doubling errors (Is the boy who is smoking is crazy?) suggests a sensitivity to surface co‐occurrence patterns in the input. This article concludes that current data do not provide any support for the claim that structure dependence is an innate constraint, and that it is possible that children form a structure‐dependent grammar on the basis of exposure to input that exhibits this property.
The Step to Rationality: The Efficacy of Thought Experiments in Science, Ethics, and Free Will
Authors: Shepard Roger N.
Published: February 2008

Examples from Archimedes, Galileo, Newton, Einstein, and others suggest that fundamental laws of physics were—or, at least, could have been—discovered by experiments performed not in the physical world but only in the mind. Although problematic for a strict empiricist, the evolutionary emergence in humans of deeply internalized implicit knowledge of abstract principles of transformation and symmetry may have been crucial for humankind's step to rationality—including the discovery of universal principles of mathematics, physics, ethics, and an account of free will that is compatible with determinism.
Calmodulin Regulation of NaV1.4 Current: Role of Binding to the Carboxyl Terminus
Authors: Biswas Subrata , Deschênes Isabelle , DiSilvestre Deborah , Tian Yanli , Halperin Victoria L. , Tomaselli Gordon F.
Published: February 2008

Calmodulin (CaM) regulates steady-state inactivation of sodium currents (NaV1.4) in skeletal muscle. Defects in Na current inactivation are associated with pathological muscle conditions such as myotonia and paralysis. The mechanisms of CaM modulation of expression and function of the Na channel are incompletely understood. A physical association between CaM and the intact C terminus of NaV1.4 has not previously been demonstrated. FRET reveals channel conformation-independent association of CaM with the C terminus of NaV1.4 (CT-NaV1.4) in mammalian cells. Mutation of the NaV1.4 CaM-binding IQ motif (NaV1.4IQ/AA) reduces cell surface expression of NaV1.4 channels and eliminates CaM modulation of gating. Truncations of the CT that include the IQ region abolish Na current. NaV1.4 channels with one CaM fused to the CT by variable length glycine linkers exhibit CaM modulation of gating only with linker lengths that allowed CaM to reach IQ region. Thus one CaM is sufficient to modulate Na current, and CaM acts as an ancillary subunit of NaV1.4 channels that binds to the CT in a conformation-independent fashion, modulating the voltage dependence of inactivation and facilitating trafficking to the surface membrane.
The Search for Comparability: Response to Binder
Authors: Chiou Fang-Yi , Rothenberg Lawrence S.
Published: February 2008

Binder (n.d., Taking the measure of Congress: Reply to Chiou and Rothenberg. Political Analysis. Forthcoming) highlights areas of agreement and disagreement with our discussion of preference measurement and legislative gridlock. We now both agree that W-NOMINATE scores—employed in Binder (1999, The dynamics of legislative gridlock. American Political Science Review 9:519–33) to measure key independent variables, including bicameral differences—should not be used when examining multichamber legislatures over time. We continue to disagree over whether Common Space scores or Binder's conference vote measure is superior. In this response, we show that, although several of the theoretical and statistical objections that Binder (n.d.) raises to our Common Space measure do not apply, they are all relevant for her conference vote analog. Additionally, we detail how, despite protests to the contrary, the conference vote measure is plagued by insufficient data. Finally, we demonstrate how new efforts to show that Binder's (1999) results continue to hold are not robust.
Modeling Committee Chair Selection in the U.S. House of Representatives
Authors: Cann Damon M.
Published: February 2008

For many years, committee chairs have been selected on the basis of seniority. Recent work has suggested that alternative factors, specifically financial support of party goals and party unity, have diminished the importance of seniority in committee chair selection. However, previous work has either failed to quantify these effects or has done so with inappropriate methods. This paper argues for the use of a Bayesian conditional logit estimator to correctly model committee chair selection in the U.S. House of Representatives. Results show a declining commitment to seniority throughout the Republican era and support the importance of fundraising as a determinant of committee chair selection. This paper shows that two other factors, financial support of party goals and party unity, have essentially replaced seniority as the central criteria for selecting committee chairs.
Abortions in dromedaries (Camelus dromedarius) caused by equine rhinitis A virus
Authors: Wernery Ulrich , Knowles Nick J. , Hamblin Chris , Wernery Renate , Joseph Sunitha , Kinne Joerg , Nagy Peter
Published: February 2008

A virus was isolated from aborted dromedary (Camelus dromedarius) fetuses during an abortion storm in Dubai, United Arab Emirates. Laboratory investigations showed the causative agent to be indistinguishable from equine rhinitis A virus (ERAV), a picornavirus. Two pregnant dromedaries experimentally infected with the camel virus isolate both aborted and an identical virus was reisolated from both fetuses, thus confirming the diagnosis. The extremely high prevalence of antibody (>90 %) and the high titres recorded against ERAV in the dromedary herd clearly showed that ERAV does infect dromedaries. Unlike horses, where ERAV targets the upper respiratory tract, in dromedaries the target organ appears to be the genital tract.
Feline immunodeficiency virus dendritic cell infection and transfer
Authors: Sprague Wendy S. , Robbiani Melissa , Avery Paul R. , O'Halloran Kevin P. , Hoover Edward A.
Published: February 2008

Feline immunodeficiency virus (FIV) interacts with dendritic cells (DC) during initiation of infection, but whether DC support or transfer FIV infection remains unclear. To address this issue, we studied the susceptibility of feline myeloid DC to FIV infection and assessed potential transfer of infection from DC to CD4+T cells. FIV was detected in membrane-bound vesicles of DC within 2 h of inoculation, although only low concentrations of FIV DNA were found in virus-exposed isolated DC. Addition of resting CD4+T cells increased viral DNA levels; however, addition of activated CD4+T cells resulted in a burst of viral replication manifested by FIV p27 capsid antigen generation. To determine whether transfer of FIV infection required productively infected DC (vs virus bound to DC but not internalized), virus-exposed DC were cultured for 2 days to allow for degradation of uninternalized virus and initiation of infection in the DC, then CD4+T blasts were added. Infection of T cells remained robust, indicating that T-cell infection is likely to be mediated byde novoviral infection of DC followed by viral transfer during normal DC/T-cell interactions. We conclude that feline DC support restricted FIV infection, which nevertheless is sufficient to efficiently transfer infection to susceptible T cells and trigger the major burst of viral replication. Feline DC/FIV/T-cell interactions (similar to those believed to occur in human immunodeficiency virus and simian immunodeficiency virus infections) highlight the means by which immunodeficiency-inducing lentiviruses exploit normal DC/T-cell interactions to transfer and amplify virus infection.
APOBEC3G upregulation by alpha interferon restricts human immunodeficiency virus type 1 infection in human peripheral plasmacytoid dendritic cells
Authors: Wang Feng-xiang , Huang Jialing , Zhang Hangxiang , Ma Xinliang , Zhang Hui
Published: February 2008

APOBEC3G (A3G), a member of cytidine deaminase family, has potent anti-human immunodeficiency virus type 1 (HIV-1) activity. It has been demonstrated that alpha interferon (IFN-α) can significantly enhance the expression of A3G in human primary resting CD4+ T-cells, macrophages and primary hepatocytes, subsequently decreasing their viral susceptibility. Plasmacytoid dendritic cells (pDCs) are key effectors in innate host immunity, mediating adaptive immune responses and stimulating IFN-α production in reaction to various stimuli. In this report, we demonstrate that IFN-α, either exogenously added to- or endogenously secreted by pDCs, can enhance the expression of A3G and its family members such as A3A, A3C and A3F. We have also shown that IFN-α can inhibit HIV-1 expression in pDCs. This inhibitory effect could be countered by addition of an A3G-specific short interfering RNA, indicating that IFN-α-induced A3G plays a key role in mediating pDCs response to HIV-1. Given the central role played by pDCs in orchestrating the IFN-α/A3G intercellular network and intracellular signal pathway, our data indicate that pDCs themselves are also protected by an IFN-α/A3G-mediated innate immunity barrier from HIV-1 infection.
Genetic and developmental effects, and morphological influences on the acoustic structure of individual distance calls in female Bengalese finchesLonchura striatavar.domestica
Authors: Soma Masayo , Hasegawa Toshikazu , Okanoya Kazuo
Published: February 2008

Recent studies of the vocal mechanisms of songbirds have shown that there are physical effects on sound production. Interspecific and phylogenetic comparisons have shown that body mass and bill morphology are two major factors affecting vocalizations such as songs. We analyzed the distance calls of female Bengalese finchesLonchurastriatavar.domestica, the non‐vocal learning sex, to assess the potential physical effects on the acoustic structure of vocalizations. By experimentally controlling rearing condition using cross‐fostering we could examine the effects of the developmental environment and genetic background. None of the tested factors affected the peak frequency of the distance calls, but we found that larger‐billed birds tended to produce shorter bout calls with higher trill rates. These results suggest that the divergence of bill morphology can affect acoustic features at the within‐population level. We also found that the birds reared in the same foster brood and siblings from the same genetic parents tended to produce calls with similar trill rates. This implies that the trill rate is under the influence of developmental and genetic factors.
Trapping initiates stress response in breeding and non‐breeding house sparrows Passer domesticus: implications for using unmonitored traps in field studies
Authors: Lynn Sharon E. , Porter Anthony J.
Published: February 2008

In response to a variety of unpredictable conditions, birds secrete the steroid hormone corticosterone, which has numerous effects on physiology and behavior. A standardized protocol of handling and restraint has been demonstrated to elicit a robust corticosterone response in many species of birds. In contrast, comparatively little is known about the effects of capture technique on corticosterone secretion in wild birds. Setting up multiple live traps checked at regular intervals allows field researchers to capture many birds in a short period of time. However, one potential drawback of this technique is that birds may spend unknown lengths of time in traps prior to sampling. Many birds appear to remain calm and/or feed during this period, potentially leading researchers to assume that corticosterone secretion is unaffected by trapping. We assessed the impact of being left in traps for up to 30 minutes on baseline corticosterone and subsequent corticosterone responses to restraint in non‐breeding and breeding house sparrows Passer domesticus. Traps were baited with seed, and birds were either removed immediately after entry (controls), or left in the trap undisturbed for 15 or 30 min. Upon removal, birds were subjected to a standardized handling/restraint protocol in which blood samples were collected within 3 min, and again at regular intervals for 60 min. Analysis of blood samples revealed that both non‐breeding and breeding sparrows that were held in the traps had significantly higher baseline corticosterone than controls, and showed no further increase in corticosterone secretion in response to handling. However, corticosterone responses to trapping differed seasonally. Our study indicates that although birds did not exhibit prolonged escape behavior while trapped, entry into a walk‐in trap initiated a robust stress response. Taken together with data from a previous study, our data suggest that ornithologists should consider species‐specific and stage‐specific effects of trapping on physiology when designing field studies.
Assortative mating also indicates that common crossbill Loxia curvirostra vocal types are species
Authors: Edelaar Pim
Published: February 2008

Compared to most other birds, the taxonomy of crossbills (Loxia) is still highly unsettled. However, much progress seems to be achievable when data on vocalisations is included. In a recent paper, Summers et al. (2007) argued that strong assortative mating indicated that parrot crossbill Loxia pytyopsittacus, Scottish crossbill Loxia scotica and common crossbill Loxia curvirostra behave as good species when breeding in sympatry. Here I argue that their data, when placed in the context of other studies, also indicate that three vocally differentiated European populations within the common crossbill are species (following the biological species concept of Mayr (1963): species are groups of interbreeding natural populations that are reproductively isolated from other such groups). If this tentative conclusion remains to be upheld, it might have large repercussions for our understanding of the speciation process as well as for a number of more applied issues such as the discovery and description of biodiversity and the conversation of mobile, cryptic species.
The effects of aminophylline on bispectral index during inhalational and total intravenous anaesthesia*
Authors: Hüpfl M. , Schmatzer I. , Buzath A. , Burger H. , Hörauf K. , Ihra G. , Marhofer P. , Nagele P.
Published: February 2008

Aminophylline is usually used during anaesthesia to treat bronchospasm but recent findings suggest that it can also be used to shorten recovery time after general anaesthesia. However, it is unclear whether aminophylline shows similar properties during a steady‐state phase of deep surgical anaesthesia. We therefore wanted to test the hypothesis that the administration of aminophylline leads to an increase in bispectral index as a surrogate parameter suggesting a lighter plane of anaesthesia. The study was designed as a double‐blind, randomised, controlled trial with two main groups (aminophylline and placebo) and two subgroups (sevoflurane and propofol). We studied 60 patients. The injection of aminophylline 3 mg.kg−1 was associated with significant increases in bispectral index up to 10 min after its injection, while heart rate and blood pressure did not change. It appears that aminophylline has the ability to partially antagonise the sedative effects of general anaesthetics.
Assessing the significance of along‐strike variations of middle to late Miocene prograding clinoformal sequence geometries beneath the New Jersey continental shelf
Authors: Fulthorpe Craig S. , Austin James A.
Published: February 2008

Seismic mapping of high‐resolution multichannel seismic profiles along the New Jersey margin illustrates how characteristics of middle–late Miocene clinoformal sequence boundaries (SBs) change markedly along strike in presumed response to local depositional and erosional processes. Most SBs converge from SW to NE, in part as a result of the influence of underlying basin morphology on accommodation space, but also in response to differential subsidence and presumed along‐strike variations in sediment supply from the adjacent margin. The curvature of clinoform breaks, historically viewed as marking palaeo‐shelf edges, is variable and such breaks are rarely sharp. Gently curved palaeo‐shelf/slope transitions cannot be assigned precise palaeobathymetric significance and probably instead reflect post‐depositional sediment reworking. The amount of erosional truncation landward of clinoform breaks varies significantly. Documented along‐strike variability in SB morphology occurs, even though middle–late Miocene palaeo‐shelf edges are nearly linear in plan view. Therefore, such linearity cannot be a product of uniform sedimentary processes and/or accumulation along strike, but instead reflects elongation of depocentres of originally variable cross‐sectional geometry, possibly with the assistance of along‐strike currents. The observed lateral geometric heterogeneity of Neogene sequences can exert profound and unwanted influences on the outcome of scientific drilling intended to calibrate seismic stratigraphic interpretations in the absence of sufficient three‐dimensional (3D) seismic control.
Use of β2 agonists and risk of acute myocardial infarction in patients with hypertension
Authors: De Vries Frank , Pouwels Sander , Bracke Madelon , Lammers Jan‐Willem , Klungel Olaf , Leufkens Hubert , Van Staa Tjeerd
Published: February 2008

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• Use of β2 agonists has been associated with tachycardia, an abnormal ECG and atrial fibrillation.

• Previous observational studies of the association between use of β2 agonists and the risk of acute myocardial infarction (MI) have demonstrated conflicting results.

• Instead of a causal effect, the positive association between β2 agonist use and MI may be explained by latent ischaemic heart disease, which has symptoms that appear similar to respiratory complaints in chronic obstructive pulmonary disease.

WHAT THIS STUDY ADDS

• The majority of β2 agonist users in our study population did not have an increased risk of nonfatal acute MI.

• Only patients with ischaemic heart disease and who had recently started β2 agonists had an increased risk of acute MI.

• It is likely that this increased risk was related to latent cardiovascular disease rather than direct effects of β2 agonists.

AIM Observational retrospective studies of the association between use of β2 agonists and the risk of acute myocardial infarction (MI) have demonstrated conflicting results, particularly among first‐time users. The aim of this study was to examine the association between β2 agonist use and first nonfatal acute MI.

METHODS We conducted a case–control study (2476 cases) nested in a cohort of antihypertensive drug users in the Dutch PHARMO RLS database. PHARMO RLS consists of drug dispensing linked to the national hospitalizations register. Each case of nonfatal acute MI was matched with up to 12 control patients by gender, age and region. Drug and disease history and the severity of the underlying respiratory disease were adjusted for.

RESULTS Risk of acute MI was increased in current β2 agonist users [crude odds ratio (OR) 1.36, 95% confidence interval (CI) 1.15, 1.61]. However, this excess risk was reduced after adjustment for severity of asthma and chronic obstructive pulmonary disease (adjusted OR 1.18, 95% CI 0.93, 1.49). The risk was highest in patients with ischaemic heart disease and low cumulative dose of β2 agonists (adjusted OR 2.47, 95% CI 1.60, 3.82).

CONCLUSION Most users of β2 agonists did not have an increased risk of acute MI. Only patients with ischaemic heart disease with low cumulative exposure to β2 agonists had an increased risk of acute MI. It is likely that this increased risk was related to latent cardiovascular disease rather than to the direct effects of β2 agonists.
Parathyroid response to vitamin D insufficiency: relations to bone, body composition and to lifestyle characteristics
Authors: Rejnmark Lars , Vestergaard Peter , Brot Christine , Mosekilde Leif
Published: February 2008

Background  Vitamin D insufficiency is very common and is known to cause secondary hyperparathyroidism (SHPT). However, in some subjects the PTH response to low vitamin D levels is blunted, which has been termed functional hypoparathyroidism (FHPT).

Aim  We compared indices of calcium homeostasis, bone metabolism and body composition in subjects with differential PTH responses to low vitamin D levels.

Design  Cross‐sectional study. In 405 recent postmenopausal women with vitamin D insufficiency, we compared levels of bone turnover markers, bone mineral density (BMD), body composition, and body weight between subjects with SHPT and FHPT.

Results  Plasma 25‐hydroxyvitamin D (P‐25OHD) levels were slightly higher (P < 0·05) in SHPT compared with FHPT. SHPT was associated with higher levels of osteocalcin and bone‐specific alkaline phosphatase, whereas whole body BMD and hip‐ and lumbar spine‐BMD were significantly reduced. Subjects with SHPT had a 7% (P < 0·01) higher body weight and a 23% higher fat mass (P < 0·01) than subjects with FHPT, whereas lean tissue mass did not differ between groups. In SHPT, fat mass was increased by 14% (P < 0·001) at the upper and lower extremities and by 33% (P < 0·001) at the trunk. In a regression model, significant predictors of fat mass was P‐PTH (rp = 0·248, P < 0·01) and P‐osteocalcin (rp = –0·115, P = 0·02), with no effects of P‐25OHD or P‐creatinine levels.

Conclusions  Effects of vitamin D insufficiency on bone is associated with the PTH responses. The increased body weight and fat mass in SHPT compared with FHPT may imply that PTH excess contributes to fat accumulation.
A systematic review examining the effects of therapeutic radioactive iodine on ovarian function and future pregnancy in female thyroid cancer survivors
Authors: Sawka Anna M. , Lakra Deepak C. , Lea Jane , Alshehri Bandar , Tsang Richard W. , Brierley James D. , Straus Sharon , Thabane Lehana , Gafni Amiram , Ezzat Shereen , George Susan R. , Goldstein David P.
Published: February 2008

Background  For women with differentiated thyroid carcinoma (DTC), the effect of radioactive iodine (RAI) therapy on gonadal and reproductive function is an important consideration.

Objective and methods  We systematically reviewed controlled studies examining the gonadal and reproductive effects of RAI therapy in women and adolescents surviving DTC. We searched nine electronic databases. All abstracts and papers were independently reviewed by two reviewers.

Results  After reviewing 349 unique citations and 61 full‐text papers, 16 papers including data from 3023 women or adolescents with DTC were included. All studies were observational, with no long‐term randomized control trial data. The age at first RAI treatment varied from 8 to 50 years and the cumulative activities of RAI administered for treatment varied from 30 to 1099 mCi. Transient absence of menstrual periods occurred in 8–27% of women within the first year after RAI, particularly in older women. In addition, RAI‐treated women experienced menopause at a slightly younger age than women not treated with RAI. In the first year after RAI therapy, several studies reported increased rates of spontaneous and induced abortions. However, RAI treatment for DTC was generally not associated with a significantly increased risk of long‐term infertility, miscarriage, induced abortions, stillbirths, or offspring neonatal mortality or congenital defects.

Conclusions  In female survivors of DTC, there is little observational evidence to suggest important adverse effects of RAI treatment on gonadal function, fertility or pregnancy outcomes beyond 12 months, with the exception of a possible slightly earlier age of menopause.
Plasma matrix metalloproteinase‐9 levels and blood pressure in short children born small for gestational age and effects of growth hormone treatment
Authors: Willemsen Ruben H. , Van Dijk Marije , De Kort Sandra W. K. , Van Toorenenbergen Albert W. , Hokken‐Koelega Anita C. S.
Published: February 2008

Context  Short small‐for‐gestational‐age (SGA) children have an increased systolic blood pressure (BP) that decreases during long‐term GH treatment. The underlying mechanism is still unknown. Matrix metalloproteinases (MMPs) are zinc‐dependent endoproteinases that are involved in the remodelling of the extracellular matrix (ECM) and are thought to play a role in atherosclerosis. High MMP‐9 levels are found in hypertensive patients and predict cardiovascular mortality.

Objectives  To investigate whether GH treatment affects plasma MMP‐9 levels in short SGA children and whether these are related to BP.

Design  Case–control study.

Intervention  GH treatment vs. no treatment during 36 months.

Patients  Thirty‐eight short SGA children receiving GH treatment vs. 17 sex‐ and age‐matched untreated short SGA controls.

Outcome measure  Plasma MMP‐9 levels and BP were measured at baseline, and after 6, 12 and 36 months of study.

Results  MMP‐9 decreased significantly during 3 years of GH treatment but remained similar in untreated SGA controls. After 3 years of GH treatment, MMP‐9 levels were significantly lower in the GH group than in the untreated SGA controls. Systolic BP SDS significantly decreased in the GH group but remained unaltered in the untreated SGA controls. MMP‐9 levels did not correlate with systolic or diastolic BP.

Conclusions  Plasma MMP‐9 levels and systolic BP SDS decreased to almost 50% of baseline values in the GH group but remained unchanged in untreated SGA controls. Our data indicate that GH has a positive effect on both MMP‐9 levels and systolic BP SDS.
Visions of a more precise soil biology
Authors: Andrén O. , Kirchmann H. , Kätterer T. , Magid J. , Paul E. A. , Coleman D. C.
Published: February 2008

Soils have often been viewed as a black box. Soil biology is difficult to study with the precision we would wish, due to the presence of considerable soil heterogeneity, a huge diversity of organisms, and a plethora of interacting processes taking place in a complex physical‐chemical environment. We have isolated a tiny fraction of the known organisms, and the possible interactions of soil parent materials, landscape, land use, depth and time with the biota mean that we are to some extent still fumbling in the dark. There have been great advances, but we argue that the pace of advance could be faster. To progress, science needs new theory and concepts but also acceptable methodologies. Coherent and generally accepted theoretical knowledge exists in many areas, but there is a shortage of valid and exact methods to test new and sometimes even old hypotheses. New methods add knowledge, but they also can add to the confusion if they are not tied to the existing knowledge base. We speculate on how to improve soil biology through improving the way we perform and interpret research. Can we deal with soil variability? Can we measure the critical variables with adequate precision to test our hypotheses? Can we avoid reinventing the wheel? Can we find a balance between the freedom to test new and maybe even controversial ideas and the control and direction of research required by society?
El Niño and sea level anomalies: a global perspective
Authors: Tingstad Abbie H. , Smith David E.
Published: February 2008

The anomalous weather patterns observed world‐wide associated with El Niño are often accompanied by changes in local sea levels. Sea level anomalies are transmitted through various oceanic and atmospheric pathways and data suggest that this effect is currently on the order of tens of centimetres in some areas both within and outside of the equatorial Pacific. Positive sea level anomalies either generated or enhanced by El Niño have been linked to powerful storm waves and coastal flooding.
Rock, Rail and Roade—uncovering a geological treasure
Authors: Woods Mark , Barron Mark , Hobbs Peter , Boon David
Published: February 2008

Railway cuttings, like that at Roade, near Northampton in the English East Midlands, can provide a wealth of geological information, but for safety reasons they remain off‐limits to the majority of geologists. Even when access can be achieved, observations are often limited by the extent of vegetation cover. However, a new programme of engineering works at Roade has allowed Natural England and the British Geological Survey (BGS) to explore new ways of capturing the geological and topographical data from railway cuttings that could eventually allow everyone to make a virtual reality visit to otherwise inaccessible sites.
Unification of single‐configuration seismic imaging processes
Authors: Jaramillo H. , Albertin U.
Published: February 2008

In this paper we derive an integral formula that encompasses all linear processes on seismic data. These include migration, demigration and residual migration, as well as data mapping procedures such as transformation to zero offset, inverse transformation to zero offset, residual transformation to zero offset and offset continuation. The derivation of the equation is different from all previous approaches to unification. Here we do not use a cascaded operation between two operators, but rather the superposition principle. In this regard, the derivation is not only more fundamental, but also simpler and more general. We study the kinematics and the dynamics of these processes and show that the signals can be reconstructed asymptotically either by finding the envelope of particular surfaces or by stacking energy along “adjoint” surfaces. For example, in the case of migration, the first set of surfaces are isochrons, while the “adjoint” surfaces are diffraction responses. In practice, the distinction between these two types of surfaces is equivalent to choosing the order of the computational loops with regard to the input and output seismic traces.
A frequency criterion for optimal node selection in smoothing with cubic splines
Authors: Schleicher Jörg , Biloti Ricardo
Published: February 2008

When smoothing a function with high‐frequency noise by means of optimal cubic splines, it is often not clear how to choose the number of nodes. The more nodes are used, the closer the smoothed function will follow the noisy one. In this work, we show that more nodes mean a better approximation of Fourier coefficients for higher frequencies. Thus, the number of nodes can be determined by specifying a frequency up to which all Fourier coefficients must be preserved and increasing the number of nodes until this criterion is met. A comparison of the corresponding smoothing results with those obtained by filtering using moving average and moving median filters of corresponding length and a low pass with corresponding high‐cut frequency shows that optimal cubic splines yield better results as they preserve not only the desired low‐frequency band but also important high‐frequency characteristics.
Laboratory estimates of normal and shear fracture compliance
Authors: Lubbe R. , Sothcott J. , Worthington M.H. , McCann C.
Published: February 2008

Laboratory estimates of the normal (Bn) and shear (Bt) compliance of artificial fractures in samples of Jurassic and Carboniferous limestone under wet and dry conditions are presented. The experiments were performed over a range of confining pressures (from 5 MPa up to 60 MPa), at ultrasonic frequencies in a Triaxial Hoek cell, using the pulse‐echo reflection technique. The results of this study confirm that the Bn/Bt ratio of a fracture is dependent on the fluid fill. A value of Bn/ Bt of less than 0.05 was obtained for our wet (honey saturated) sample which is consistent with the prediction that this ratio should be close to zero for fluid saturated fractures. Values of Bn/Bt for the dry sample are significantly higher and increase with confining pressure from 0.2 to 0.5. It is suggested that a Bn/Bt ratio of 0.5 is probably a more representative value to use in modelling studies of gas filled fractures than the common assumption that Bn ≈ Bt.