bluuebunny/crossref_metadata_2025 huggingface dataset:
Potential impacts of a changing Arctic on community water sources on the Seward Peninsula, Alaska
Authors: Chambers Molly , White Daniel , Busey Robert , Hinzman Larry , Alessa Lilian , Kliskey Andrew
Published: December 2007

This paper discusses the potential impacts of climate change on community drinking water sources on the Seward Peninsula. The vulnerability assessment was largely based on the likelihood that the water source would be impacted by a change in the permafrost regime. Factors that were considered were the likely change in the permafrost condition of a watershed, the watershed area, and the contribution of groundwater to streamflow. Results showed that the change in permafrost condition is likely to impact some communities much more than others, even though the communities are near to each other. Communities that will experience little change to the permafrost in their watersheds, have a significant contribution of base flow to their streams and rivers, or have water sources with large watersheds were not found to be vulnerable. On the other hand, communities with small watersheds, watersheds that were likely to see a significant change in the permafrost regime, or watersheds with little winter base flow were seen to be vulnerable to climate change. The results of this work could be valuable to community leadership when considering future vulnerability. The same approach could be used across the Arctic to assess the potential impact of climate change on community water sources and ultimate sustainability.
Edge‐modulated stagnant‐lid convection and volcanic passive margins
Authors: Sleep Norman H.
Published: December 2007

The initial oceanic crust along volcanic passive margins is a factor of ∼3 greater than that of typical oceanic crust (20 versus 6–7 km). Convection driven by the edge of the continental lithosphere may cause mantle material to circulate through the shallow zone of significant melting beneath the nascent ocean basin and cause the volume of melted mantle to exceed that required to replace the diverging lithospheric plates. This hypothesis is a well‐known alternative to mantle plumes. I obtain dimensional scaling relations and develop numerical models which indicate that the melted volume is unlikely to be enhanced by a factor of ∼3. This conclusion agrees with the results of numerical calculations by Nielsen and Hopper (2002, 2004). Dimensional scaling provides the relationship which shows that the vigor of convection in terms of laterally averaged heat flow (or flow velocity) depends on the square of local thickness of the rheological boundary layer (for linear viscosity). The derivation does not involve undulations in lithospheric thickness and thus provides the inference that the vigor of stagnant‐lid convection depends only weakly on those features. Numerical models support this inference. Lithospheric edges do nucleate instabilities, but these instabilities are similar in magnitude to those in models started with a tiny perturbation from laterally homogeneous temperature. Subsequent convection is also similar for models started with tiny perturbations and with large lateral variations in lithospheric thickness. In terms of the scaling relationship, the asthenosphere beneath the thin lithosphere within rifts is an unfavorable site for circulation and extensive melting. The rheological boundary layer is in general thin below thin lithosphere, which causes stagnant‐lid convection there to be weak. Care needs to be taken in numerical modeling of convection beneath passive margins. Starting conditions that drive large instabilities of features that could not have persisted in the Earth need to be avoided. Models should start rifting only after mature stagnant‐lid convection is established.
Internal waves across the Pacific
Authors: Alford M. H. , MacKinnon J. A. , Zhao Zhongxiang , Pinkel Rob , Klymak Jody , Peacock Thomas
Published: December 2007

The long‐range propagation of the semidiurnal internal tide northward from the Hawaiian ridge and its susceptibility to parametric subharmonic instability (PSI) at the “critical latitude,” λc = 28.8°N, were examined in spring 2006 with intensive shipboard and moored observations spanning 25–37°N along a tidal beam. Velocity and shear at λc were dominated by intense vertically‐standing, inertially‐rotating bands of several hundred meters vertical wavelength. These occurred in bursts following spring tide, contrasting sharply with the downward‐propagating, wind‐generated features seen at other latitudes. These marginally‐stable layers (which have inverse 16‐meter Richardson number Ri16−1 = 0.7) are interpreted as the inertial waves resulting from PSI of the internal tide. Elevated near‐inertial energy and parameterized diapycnal diffusivity, and reduced asymmetry in upgoing/downgoing energy, were also observed at and equatorward of λc. Yet, simultaneous moored measurements of semidiurnal energy flux and 1‐km‐deep velocity sections measured from the ship indicate that the internal tide propagates at least to 37°N, with no detectable energy loss or phase discontinuity at λc. Our observations indicate that PSI occurs in the ocean with sufficient intensity to substantially alter the inertial shear field at and equatorward of λc, but that it does not appreciably disrupt the propagation of the tide at our location.
Repeating earthquakes and seismic potential along the northern Longitudinal Valley fault of eastern Taiwan
Authors: Rau Ruey‐Juin , Chen Kate Huihsuan , Ching Kuo‐En
Published: December 2007

The northern Longitudinal Valley fault in eastern Taiwan creeps at the surface with a small rate of ∼1 cm/yr but slips in large earthquakes. To improve seismic hazard assessment, it is important to comprehend the slip deficit rate distribution at depth. We discovered 25 ML 2.1–4.6 repeating earthquakes in this area and inverted GPS measurements for producing an image of the along‐strike spatial distribution of deep fault slip rates. The repeating events are located at the depths of 10–22 km with 24.9–77.5 mm/yr slip rates, which are comparable with the GPS‐derived slip rates of 47.5 ± 5.8 mm/yr at similar depth ranges. Based on distribution of GPS‐derived slip deficits, since 1951, the northern Longitudinal Valley fault has become capable of releasing stored strain in a future Mw = 7.3 earthquake.
A new technique for estimating outgoing longwave radiation using infrared window and water vapor radiances from Kalpana very high resolution radiometer
Authors: Singh Randhir , Thapliyal P. K. , Kishtawal C. M. , Pal P. K. , Joshi P. C.
Published: December 2007

A new technique for estimating the outgoing longwave radiation (OLR) from the radiances observations in the infrared window (WIN; 10.5–12.5 μm) and water vapor (WV; 5.7–7.1 μm) channels onboard the geostationary operational Indian National Satellite (INSAT) Kalpana has been developed. The OLR is estimated from the WIN and WV radiances via genetic algorithm (GA). The transfer functions that relate OLR and narrowband radiances (WIN and WV) were developed using radiative transfer model. It is shown that inclusion of the WV information in the development of transfer function significantly reduces the OLR retrieval error as compared to the single WIN channel approach. The analysis shows that the model OLR may be retrieved within 2.5 Wm−2 rmse using WIN and WV channels, which is smaller than the rmse by earlier methods used for OLR estimation using two channels (WIN and WV). GA technique shows the clear advantage over multi‐channel regression in the OLR retrieval from WIN and WV radiances.
Urban heat island in the subsurface
Authors: Ferguson Grant , Woodbury Allan D.
Published: December 2007

The urban heat island effect has received significant attention in recent years due to the possible effect on long‐term meteorological records. Recent studies of this phenomenon have suggested that this may not be important to estimates of regional climate change once data are properly corrected. However, surface air temperatures within urban environments have significant variation, making correction difficult. In the current study, we examine subsurface temperatures in an urban environment and the surrounding rural area to help characterize the nature of this variability. The results of our study indicate that subsurface temperatures are linked to land‐use and supports previous work indicating that the urban heat island effect has significant and complex spatial variability. In most situations, the relationship between subsurface and surface processes cannot be easily determined, indicating that previous studies that relying on such a linkage may require further examination.
Impact of ice supersaturated regions and thin cirrus on radiation in the midlatitudes
Authors: Fusina F. , Spichtinger P. , Lohmann U.
Published: December 2007

In this study we investigate the radiative impact of ice supersaturated regions (ISSRs, i.e., cloud free air masses in the upper troposphere that are supersaturated with respect to ice) and thin cirrus. For this purpose we use corrected radiosonde data obtained from routine measurements over the meteorological observatory in Lindenberg, Germany. The radiative effect of the measured ice supersaturation is determined. By constructing an idealized profile from the measurement data the radiative properties of ISSRs and thin cirrus containing ice supersaturation were studied. The impact of ISSRs on the surface forcing is negligible but locally, within the vertical profile, changes in the heating rates up to 1 K d−1 for typical values of 130% relative humidity with respect to ice compared to the saturated profiles are found. This is also important for the local dynamics within the supersaturated layers. The outgoing longwave radiation due to the enhanced water vapor content inside ISSRs decreases up to 0.8 W m−2. The radiative impact of thin cirrus is much stronger. Thin cirrus influence the surface budget, the top of the atmosphere radiation and the vertical profile of the heating rates. Changes in the outgoing longwave radiation and in the reflected shortwave flux at top of the atmosphere up to 64 W m−2 and 79 W m−2, respectively, are possible. Changes in the surface flux (downward) up to 89 W m−2 are found. The maximal heating rate differences between thin cirrus and ISSR amount to 15 K d−1. The radiative impact of thin cirrus clouds depends strongly on cloud ice content and the size of the ice crystals. Additionally, the radiative impact of cirrus formed by parameterizations not allowing ice supersaturations in large‐scale models is estimated. The errors due to artificially formed cirrus are quite large; differences up to 3 K d−1 in the vertical heating profiles and up to 38 and 40 W m−2 in the outgoing longwave radiation and the surface flux, respectively, are found. Thus we recommend using physically based parameterizations in GCMs which allow ice supersaturation.
Potassium channels in the regulation of pulmonary artery smooth muscle cell proliferation and apoptosis: pharmacotherapeutic implications
Authors: Burg E D , Remillard C V , Yuan J X‐J
Published: December 2007

Maintaining the proper balance between cell apoptosis and proliferation is required for normal tissue homeostasis; when this balance is disrupted, disease such as pulmonary arterial hypertension (PAH) can result. Activity of K+channels plays a major role in regulating the pulmonary artery smooth muscle cell (PASMC) population in the pulmonary vasculature, as they are involved in cell apoptosis, survival and proliferation. PASMCs from PAH patients demonstrate many cellular abnormalities linked to K+channels, including decreased K+current, downregulated expression of various K+channels, and inhibited apoptosis. K+is the major intracellular cation, and the K+current is a major determinant of cell volume. Apoptotic volume decrease (AVD), an early hallmark and prerequisite of programmed cell death, is characterized by K+and Cl−efflux. In addition to its role in AVD, cytosolic K+can be inhibitory toward endogenous caspases and nucleases and can suppress mitochondrial cytochromecrelease. In PASMC, K+channel activation accelerates AVD and enhances apoptosis, while K+channel inhibition decelerates AVD and inhibits apoptosis. Finally, inhibition of K+channels, by increasing cytosolic [Ca2+] as a result of membrane depolarization‐mediated opening of voltage‐dependent Ca2+channels, leads to PASMC contraction and proliferation. The goals of this review are twofold: (1) to elucidate the role of K+ions and K+channels in the proliferation and apoptosis of PASMC, with an emphasis on abnormal cell growth in human and animal models of PAH, and (2) to elaborate upon the targeting of K+flux pathways for pharmacological treatment of pulmonary vascular disease.

British Journal of Pharmacology(2008)153, S99–S111; doi:10.1038/sj.bjp.0707635; published online 17 December 2007
Endothelial α1‐adrenoceptors regulate neo‐angiogenesis
Authors: Ciccarelli M , Santulli G , Campanile A , Galasso G , Cervèro P , Altobelli G G , Cimini V , Pastore L , Piscione F , Trimarco B , Iaccarino G
Published: December 2007

Background and purpose:

Intact endothelium plays a pivotal role in post‐ischaemic angiogenesis. It is a phenomenon finely tuned by activation and inhibition of several endothelial receptors. The presence of α1‐adrenoceptors on the endothelium suggests that these receptors may participate in regenerative phenomena by regulating the responses of endothelial cells involved in neo‐angiogenesis.

Experimental approach:

We evaluated the expression of the subtypes of the α1‐adrenoceptor in isolated endothelial cells harvested from Wistar‐Kyoto (WKY) rats. We explored the possibility these α1‐adrenoceptors may influence the pro‐angiogenic phenotype of endothelial cellsin vitro.In vivo, we used a model of hindlimb ischaemia in WKY rats, to assess the effects of α1adrenoceptor agonist or antagonist on angiogenesis in the ischaemic hindlimb by laser Doppler blood flow measurements, digital angiographies, hindlimb perfusion with dyed beads and histological evaluation.

Key results:

In vitro, pharmacological antagonism of α1‐adrenoceptors in endothelial cells from WKY rats by doxazosin enhanced, while stimulation of these adrenoceptors with phenylephrine, inhibited endothelial cell proliferation and DNA synthesis, ERK and retinoblastoma protein (Rb) phosphorylation, cell migration and tubule formation.In vivo, we found increased α1‐adrenoceptor density in the ischaemic hindlimb, compared to non‐ischaemic hindlimb, suggesting an enhanced α1‐adrenoceptor tone in the ischaemic tissue. Treatment with doxazosin (0.06 mg kg−1 day−1for 14 days) did not alter systemic blood pressure but enhanced neo‐angiogenesis in the ischaemic hindlimb, as measured by all our assays.

Conclusions:

Our findings support the hypothesis that the α1‐adrenoceptors in endothelial cells provide a negative regulation of angiogenesis.

British Journal of Pharmacology(2008)153, 936–946; doi:10.1038/sj.bjp.0707637; published online 17 December 2007
Synergistic depression of NMDA receptor‐mediated transmission by ketamine, ketoprofen andL‐NAME combinations in neonatal rat spinal cordsin vitro
Authors: Lizarraga I , Chambers J P , Johnson C B
Published: December 2007

Background and purpose:

SpinalN‐methyl‐D‐aspartate (NMDA) receptor/cyclooxygenase (COX) and nitric oxide synthase (NOS) pathways play a major role in nociceptive processing, and influencing them simultaneously may induce synergistic analgesia. This study determined the spinal antinociceptive interactions between ketamine (NMDA receptor channel blocker), ketoprofen (COX inhibitor) andL‐NAME (NOS inhibitor) combinations.

Experimental approach:

Using anin vitroneonatal rat spinal cord preparation, two A‐fibre‐mediated reflexes, the monosynaptic reflex (MSR) and the low‐intensity excitatory postsynaptic potential (epsp), and one C‐fibre‐mediated reflex, the high‐intensity epsp, were evoked electrically. The effect of drugs and drug combinations on these reflexes was assessed and the type of interaction determined by isobolographic analysis.

Key results:

Infusion of ketamine alone decreased all three reflexes. That of ketoprofen decreased both the low and the high‐intensity epsp only. Infusion ofL‐NAME alone produced no significant effects. Co‐infusion of fixed ratios of IC40fractions of both (ketamine+ketoprofen) and (ketamine+L‐NAME) were synergistic for depressing the low and the high‐intensity epsps. The interaction was sub‐additive for both combinations on the MSR. The only significant effect for the (ketoprofen+L‐NAME) combination was synergism on the high‐intensity epsp.

Conclusions and implications:

All three combinations synergistically depressed nociceptive spinal transmission, and both ketamine and ketoprofen and ketamine andL‐NAME combinations did so with potentially decreased motor side effects. If such combination profiles also occurin vivo, the present findings raise the possibility of ultimate therapeutic exploitation of increased analgesia with fewer side effects.

British Journal of Pharmacology(2008)153, 1030–1042; doi:10.1038/sj.bjp.0707638; published online 17 December 2007
Validation of NMR relaxation exchange time measurements in porous media
Authors: Mitchell J. , Griffith J. D. , Collins J. H. P. , Sederman A. J. , Gladden L. F. , Johns M. L.
Published: December 2007

Two-dimensional T2-T2 NMR relaxation exchange spectroscopy has been applied to model porous media composed of mixtures of nonporous borosilicate and soda lime glass spheres in water. The spheres had a mean diameter of 100μm, thus providing an approximately constant characteristic pore dimension throughout the structures, while the use of two glass types ensured that water in different pore-space regions had significantly different T2 relaxation rates. The packed beds were constructed in various ways with controlled glass type domain sizes to rigorously validate a model for region-to-region exchange of water. From the determined exchange times, the corresponding length scales were calculated based on the molecular self-diffusion of water; these agreed to better than ±25% with the expected domain sizes. Furthermore, exchange distances on the order of the pore size were observed in thoroughly mixed systems. Depending on the relaxation rates present in the sample, this technique can provide estimates of length scales ranging from microns to millimeters.
Holographic fabrication of three-dimensional orthorhombic and tetragonal photonic crystal templates using a diffractive optical element
Authors: Poole Zsolt , Xu Di , Chen Kevin P. , Olvera Isai , Ohlinger Kris , Lin Yuankun
Published: December 2007

We report the fabrication of both orthorhombic and tetragonal photonic crystal templates using a phase mask technique. Three-dimensional photonic crystal structures were formed by a double exposure of SU8 to three-beam interference patterns generated by a phase mask. Lattice structures and photonic band gap can be controlled by rotational angles of the phase mask between two exposures. Band gap computation predicts that photonic crystal structures with the optimized band gap can be realized when the rotational angle is set between 50° and 70°. A photonic crystal template with 60° phase mask rotation was fabricated, showing improved lattice structures required for the band gap opening.
Organic photovoltaic cells with near infrared absorption spectrum
Authors: Dai Jiguang , Jiang Xiaoxia , Wang Haibo , Yan Donghang
Published: December 2007

Organic photovoltaic cells with a strong absorption spectrum in the near infrared region were fabricated with the structure of indium tin oxide (ITO)/zinc phthalocynine (ZnPc)/lead phthalocynine (PbPc)∕C60∕Al. PbPc has a broad and strong absorption, while the organic films of PbPc∕C60 showed an additional new absorption peak at 900nm. The absorption in the near infrared region can harvest more photons to invert into photocurrent. Moreover, the introduction of ZnPc thin layer between ITO and PbPc further improved the new absorption peak and the collection of hole carriers at the electrode ITO, which increased the power conversion efficiencies to 1.95% and short-circuit current density to 9.1mA∕cm2 under AM 1.5 solar spectrum.
Improved electrical performances of plasma-enhanced atomic layer deposited TaCxNy films by adopting Ar∕H2 plasma
Authors: Park Tae Joo , Kim Jeong Hwan , Jang Jae Hyuck , Na Kwang Duk , Hwang Cheol Seong , Kim Jong Hoon , Kim Gee-Man , Choi Jae Ho , Choi Kang Joon , Jeong Jae Hak
Published: December 2007

Ta C x N y films were grown by a plasma-enhanced atomic layer deposition using Ta(N-t-C5H11)[N(CH3)2]3 as the precursor and H2 or Ar∕H2 plasma as the reducing agent. The Ar∕H2 plasma appeared to efficiently break the Ta–N bonds in the Ta precursor and formed more TaCx, which significantly decreased the resistivity of the films (∼255μΩcm) compared with the case of the H2 plasma (∼1570μΩcm). The Ar∕H2 plasma also made the films denser and efficiently eliminated the oxygen from the films. This improved the resistance against the elemental diffusion as well as the aging characteristics of the films after exposure to air.
Nitrogen balances in temperate perennial grass and clover dairy pastures in south-eastern Australia
Authors: Eckard R. J. , Chapman D. F. , White R. E.
Published: December 2007

Nitrogen (N) fertiliser use on dairy pastures in south-eastern Australia has increased exponentially over the past 15 years. Concurrently, imports of supplementary feed onto dairy farms have increased, adding further nutrients to the system. These trends raise questions about the environmental effects of higher nutrient inputs to dairy farms. To gauge possible effects, annual N balances were calculated from an experiment where N inputs and losses were measured for 3 years from non-irrigated grass/clover pastures receiving either no N fertiliser (Control) or 200 kg N/ha applied annually as ammonium nitrate or urea. Estimated total N inputs, averaged over the 3 years, were 154, 314, and 321 kg N/ha.year for the control, ammonium nitrate, and urea treatments, respectively, while N outputs in meat and milk were 75, 99, and 103 kg N/ha.year, respectively. The corresponding calculated N surplus was 79, 215, and 218 kg N/ha.year for the 3 treatments, respectively, and the ratio of product N/total-N inputs for the 3 treatments ranged from 50% in the control to 32% for both N treatments. Total N losses averaged 56, 102, and 119 kg N/ha.year, leaving a positive N balance of 23, 112, and 99 kg N/ha.year for the control, ammonium nitrate, and urea treatments, respectively. The ratio of product N/total-N inputs or the N surplus may be useful in monitoring the efficiency of conversion of N into animal products and the potential environmental effect at a whole-farm scale. However, additional decision support or modelling tools are required to provide information on specific N losses for a given set of conditions and management inputs. Given the large range in N losses there is opportunity for improving N-use efficiency in dairy pastures through a range of management practices and more tactical use of grain and N fertiliser.
The dark side of an island radiation: systematics and evolution of troglobitic spiders of the genus Dysdera Latreille (Araneae : Dysderidae) in the Canary Islands
Authors: Arnedo Miquel A. , Oromí Pedro , Múrria Cesc , Macías-Hernández Nuria , Ribera Carles
Published: December 2007

The spider genus Dysdera Latreille is an excellent model for the study of the evolution of cave life: ten species are known to exist exclusively in the subterranean environment of the Canary Islands, where the genus has undergone local diversification. In the present paper, two new troglobitic species (Dysdera madai, sp. nov. and D. sibyllina, sp. nov.) and the previously unknown sex of five additional species are described and illustrated: the males of D. gollumi Ribera & Arnedo, 1994, D. hernandezi Arnedo & Ribera, 1999 and D. labradaensis Wunderlich, 1991; and the females of D. andamanae Arnedo & Ribera, 1997 and D. gibbifera Wunderlich, 1991. The first direct evidence of troglobitic members of Dysdera in micro- and mesocaverns are reported. The evolution of cave life as hypothesised following a combined morphological and molecular phylogeny is investigated. Troglobitic Canarian Dysdera species have colonised the underground on eight independent occasions. The Dysderidae groundplan represents a preadaptation to cave life and has facilitated the colonisation of caves. Canarian members of Dysdera have a predominantly parapatric mode of speciation, although postspeciation changes in distribution may have obscured allopatric processes. Eye regression and, to a lesser extent, larger body size and appendage elongation characterise troglobitic species. The different levels of troglobiomorphism are interpreted as local adaptations to heterogeneous subterranean conditions. The high levels of sympatry among troglobites are explained by trophic segregation and changes in prey capture strategy were involved in the single identified case of subterranean speciation in the group.
Post-fire ephemerals and spinifex-fuelled fires: a decision model for bilby habitat management in the Tanami Desert, Australia
Authors: Southgate Richard , Carthew Susan
Published: December 2007

Seed from post-fire ephemeral plants like Yakirra australiense can form an important component of the diet of the bilby, a threatened arid-dwelling bandicoot. An investigation was conducted to determine the factors affecting the production of Yakirra and fire reoccurrence in the Tanami Desert. A simple decision model was produced to assist managers decide where and when to burn and what to expect regarding Yakirra australiense growth following fire and rainfall. The information used in the model may be derived from existing spatial databases that document rainfall and fire history and could be used to map broad-scale temporal change in total vegetation cover and components of habitat suitability for the bilby. The season and magnitude of rainfall and time-since-fire were the most important variables in the production of Yakirra seed. Rainfall >300 mm within a 2-month period of intense-complete burns could result in >5% Yakirra cover, and >100 mm was required for >1% cover. Negligible Yakirra cover occurred in adjacent long-unburnt plots. Total ground cover and spinifex cover varied substantially in relation to mean annual rainfall, but not in relation to substrate type. Long-unburnt spinifex cover was mostly too sparse to carry a fire in the southern part of the Tanami and the growth of non-spinifex vegetation would be necessary to boost fuel loads sufficiently to carry a fire. Generally, more than 41% cover was required to carry a fire but this was also dependent on weather conditions. Managers should aim to burn in late spring or early summer to improve Yakirra production. Fire management to enhance habitat suitability for the bilby would be of most benefit in the northern part of the Tanami Desert where growth rate of vegetation is greater and there is little existing fire age heterogeneity.
Evaluation of a post-fire tree mortality model for western USA conifers
Authors: Hood Sharon M. , McHugh Charles W. , Ryan Kevin C. , Reinhardt Elizabeth , Smith Sheri L.
Published: December 2007

Accurately predicting fire-caused mortality is essential to developing prescribed fire burn plans and post-fire salvage marking guidelines. The mortality model included in the commonly used USA fire behaviour and effects models, the First Order Fire Effects Model (FOFEM), BehavePlus, and the Fire and Fuels Extension to the Forest Vegetation Simulator (FFE-FVS), has not been tested with independently collected post-fire tree mortality data. The model predicts mortality for a wide range of conifer species based on crown scorch and species-specific bark thickness. We evaluated the mortality model on 13 western USA conifers: subalpine fir, red fir, white fir, Douglas-fir, incense cedar, western larch, western hemlock, Engelmann spruce, whitebark pine, lodgepole pine, ponderosa pine, Jeffrey pine, and sugar pine. Predicted stand-level mortality was within ±20% of observed mortality for all species except incense cedar, western larch, red fir, and western hemlock. Individual tree mortality prediction was most accurate for subalpine fir, incense cedar, ponderosa pine, and Jeffrey pine. Evaluation of the model provides managers with an accuracy assessment for estimating the probability of mortality for the majority of western USA conifers when using the mortality model to make land management decisions.A
A molecular specificity code for the three mammalian KDEL receptors
Authors: Raykhel Irina , Alanen Heli , Salo Kirsi , Jurvansuu Jaana , Nguyen Van Dat , Latva-Ranta Maria , Ruddock Lloyd
Published: December 2007

AC-terminal KDEL-like motif prevents secretion of soluble endoplasmic reticulum (ER)–resident proteins. This motif interacts with KDEL receptors localized in the intermediate compartment and Golgi apparatus. Such binding triggers retrieval back to the ER via a coat protein I–dependent pathway. To date, two human KDEL receptors have been reported. Here, we report the Golgi localization of a third human KDEL receptor. Using a reporter construct system from a screen of 152 variants, we identified 35 KDEL-like variants that result in efficient ER localization but do not match the current Prosite motif for ER localization ([KRHQSA]-[DENQ]-E-L). We cloned 16 human proteins with one of these motifs and all were found in the ER. A subsequent screen by bimolecular fluorescence complementation determined the specificities of the three human KDEL receptors. Each KDEL receptor has a unique pattern of motifs with which it interacts. This suggests a specificity in the retrieval of human proteins that contain different KDEL variants.
Differential regional expression of brain-derived neurotrophic factor following olfactory fear learning
Authors: Jones Seth V. , Stanek-Rattiner Lisa , Davis Michael , Ressler Kerry J.
Published: December 2007

We examined brain-derived neurotrophic factor (BDNF) mRNA expression across the olfactory system following fear conditioning. Mice received 10 pairings of odor with footshock or equivalent unpaired odors and shocks. We found increased BDNF mRNA in animals receiving paired footshocks in the multiple regions examined including the posterior piriform cortex (PPC) and basolateral amygdala (BLA). This was in contrast to the unpaired and odor-alone treatments, where BDNF mRNA was increased in the olfactory bulb (OB) and anterior piriform cortex (APC) only, but not the higher olfactory areas. We propose that odor exposure increases expression of BDNF in the OB and APC while the PPC and BLA increase BDNF mRNA only when associative learning occurs.
The memory-impairing effects of septal GABA receptor activation involve GABAergic septo-hippocampal projection neurons
Authors: Krebs-Kraft Desiree L. , Wheeler Marina G. , Parent Marise B.
Published: December 2007

Septal infusions of the γ-aminobutyric acid (GABA)A agonist muscimol impair memory, and the effect likely involves the hippocampus. GABAA receptors are present on the perikarya of cholinergic and GABAergic septo-hippocampal (SH) projections. The current experiments determined whether GABAergic SH projections are involved in the memory-impairing effects of septal GABAA receptor activation. Experiment 1 tested whether combining septal co-infusions of subeffective doses of muscimol with scopolamine, a drug that selectively influences GABA SH projections, would produce memory deficits. Experiment 2 tested whether hippocampal infusions of a GABAA receptor antagonist would block the effects of septal muscimol infusions. Fifteen minutes prior to assessing spontaneous alternation (SA) or training in a multiple trial inhibitory avoidance (CMIA) task, male Sprague-Dawley rats were given septal infusions of vehicle, muscimol, scopolamine, or co-infusions of muscimol with scopolamine, or septal infusions of vehicle or muscimol combined with hippocampal infusions of vehicle or bicuculline. Septal co-infusions of muscimol with scopolamine significantly impaired SA and CMIA. Hippocampal bicuculline infusions blocked deficits produced by septal muscimol infusions in SA and attenuated deficits produced in CMIA. Combined, these findings suggest that GABAergic SH projections are involved in the memory-impairing effects of septal GABA receptor activation.
A GENERALIZED CONDITION FOR TELEPORTATION OF THE QUANTUM STATE OF AN ASSEMBLY OF N TWO-LEVEL SYSTEM
Authors: PRAKASH HARI , CHANDRA NARESH , PRAKASH RANJANA , DIXIT AMBESH
Published: December 2007

We consider the teleportation of quantum information consisting of the quantum state of a set S1 of N two-level systems (TLSs), using EPR entangled state consisting of set S2⊕S3 where set S2 has M TLSs and set S3 has N TLSs. The Bell state measurement is done on set S1⊕S2 and a unitary transformation, dependent on this result, on the quantum state of set S3 generates a replica of the original state of set S1. We show rigorously that the teleportation is possible only if M ≥ N.
GENERALIZED RÉNYI IMAGE ENTROPY: A NEW NOISE MEASURE
Authors: GABARDA SALVADOR , CRISTOBAL GABRIEL
Published: December 2007

Noise cannot be distinguished from information by simply measuring entropy. Nevertheless, the Rényi entropy can be used to calculate the entropy in a pixel-wise basis. Consequently, entropy histograms of images can be obtained. Hence, histograms of entropy can be used to quantify differences in the information contents of images. In this paper, entropy histograms of noisy images has been analyzed and results have been applied to define an index that measures the noise contents of natural images. The pixel-wise entropy of digital images has been calculated through the use of a spatial/spatial-frequency distribution. Therefore generalized Rényi entropy and a normalized windowed pseudo-Wigner distribution (PWD) have been selected to define a particular pixel-wise entropy. In this way, the shape of such a distribution of entropy indicates the amount of noise present in the image. Some examples are presented and discussed.
Chalk physical properties and cliff instability
Authors: Mortimore R. N. , Stone K. J. , Lawrence J. , Duperret A.
Published: December 2007

Physical properties such as porosity and intact dry density (IDD) are compared with strength testing in relation to the Chalk formations in the cliffs of the English Channel. Natural moisture contents are close to saturation moisture contents for chalks with intact dry densities above 1.70 Mg/m
3
. Below this IDD, the natural moisture contents show a much greater range and greater divergence from the saturation line. There is also an indication that certain types of chalk retain water at saturation level while others gain and lose water more readily. Strength tests (Point Load Index, Brazilian Crushing Strength and Uniaxial Compressive Strengths) show up to four times reductions in strength between dry (higher strength) and saturated (lower strength) samples. Absence of a strong correlation between density and strength is interpreted as resulting from either mineralogical differences in the samples and/or textural differences between different chalks. The variation in physical properties and strength in the different chalks forming the cliffs indicates the strong stratigraphical and sedimentological controls on mechanical performance of the material and mass in cliff failures.
Coastal chalk cliff erosion: experimental investigation on the role of marine factors
Authors: Brossard J. , Duperret A.
Published: December 2007

In this paper the marine factors of erosion contributing to the chalk cliffs located on either side of the English Channel are examined. From an analysis of the literature, the main physical phenomena determining the marine erosion of the shore platform and the foot of the cliff are considered. Field observations of the coastal chalk cliff show that the vertical erosion of the shore platform does not appear to be the main cause of cliff erosion, which is mainly governed by cliff collapse processes. To estimate the impact of waves on the base of the cliff, experiments were carried out in a wave flume. The pressure due to the waves and the dissipation of waves were measured for three simple configurations of the boundary conditions between the cliff and the sea. The pressure never exceeded the compressive strength of chalk rock. Nevertheless, pressure fluctuations due to periodic waves can induce a fatigue process within the fracture structures.

The experimental results showed that the shingle by itself has a low effect on wave energy dissipation. The main effect of shingle is to reduce the water depth at the toe of the cliff. Furthermore, it is demonstrated that a lower water depth leads to a lower impact of the waves on the cliff.
Imaging, mapping and modelling continental lithosphere extension and breakup: an introduction
Authors: Karner G. D. , Manatschal G. , Pinheiro L. M.
Published: December 2007

Abstact

This Special Publication is a direct outcome of a small but dedicated group of researchers who met in Pontresina, Switzerland, to review and define the fundamental observations characterizing extensional systems and their application in guiding and constraining modelling efforts and results. The various summaries of the keynote addresses give an objective overview of the state of the art in modelling lithospheric extensional systems, both from the regional scale using dynamic models to individual basins using kinematic models with an emphasis on capturing the extensional history of the Iberia and Newfoundland margins. At the heart of all of these efforts is a simple question: Exactly what mechanisms allow the continental lithosphere to be thinned to the point of rupture? Related questions are: (1) Do crustal and mantle faults play a major role in this thinning process? If so, what is their geometry and does their importance and geometry change with time? (2) Are there other mechanisms of lithospheric and crustal thinning that cannot be imaged on seismic sections? (3) How is deformation accommodated in space and time? (4) What role do inherited mechanical, thermal and/or chemical heterogeneities play in controlling strain distribution and localization? (5) When, how and to what degree does magma production affect the distribution and localization of extension? And (6) what is the stratigraphic record of continental extension and how does it document the extension of the crust and thinning of the lithospheric mantle?

The aim of this Special Publication is to address many of these fundamental questions concerning the extreme extension and thinning of continental lithosphere.
Nature of the continent–ocean transition zone along the southern Australian continental margin: a comparison of the Naturaliste Plateau, SW Australia, and the central Great Australian Bight sectors
Authors: Direen N. G. , Borissova I. , Stagg H. M. J. , Colwell J. B. , Symonds P. A.
Published: December 2007

We document the interpretation of three crustal sections from coincident deep seismic reflection, gravity and magnetic data acquired on Australia's southern margin: one section from the Naturaliste Plateau and the Diamantina Zone; and two in the Great Australian Bight (GAB). Interpretations are based on an integrated study of deep multichannel seismic, gravity and magnetic data, together with sparse sonobuoy and dredging information.

All interpreted sections of the margin show a transition from thinned continental crust, through a wide continent ocean transition zone (COTZ). In the GAB the transition is to slow sea-floor spreading oceanic crust that dates from breakup in the Campanian (
c
. 83 Ma); in the Naturaliste–Diamantina margin the earliest oceanic crust is undated. The COTZ on these margins is geologically and geophysically complex, but interpretation of all data, including dredge hauls, is consistent with the presence of a mixture of modified continental lower crust, breakup related volcanics and exhumed continental mantle. Serpentinized detachment faults are not well imaged, but have been inferred from high-amplitude magnetic signatures interpreted to arise from magnetite associated with the hydration of peridotites. Alternative models for the structure of the COTZ, involving either mafic underplating or aborted sea-floor spreading, have been explored, but are considered unlikely on this margin.

Similarity in the final architecture of these margins has major implications for the nature of rifting in the Southern Rift System, and may point to the entire 4000 km-long system being non-volcanic in character.

Second-order differences in geometry and morphology of the two areas studied are unlikely to be a function of strain rate. Instead, they probably reflect complexities owing to the multiple tectonic events that occurred during final Gondwanide fragmentation. The most dramatic of these is the impact of hotspot activity in the Kerguelen Plateau, which commenced some 50 Ma prior to final breakup in that sector.
Constraints on the deformation and rupturing of continental lithosphere of the Red Sea: the transition from rifting to drifting
Authors: Cochran J. R. , Karner G. D.
Published: December 2007

The Red Sea is an ideal locale for testing differing models and hypotheses for rift evolution and the initiation of sea-floor spreading. The Red Sea is an active rift system that formed by the rifting of Precambrian continental lithosphere beginning in the late Oligocene, leading to breakup and sea-floor spreading by approximately 5 Ma in the southern Red Sea to the south of about 19°30′N. In the northern Red Sea, north of approximately 23°30′N, organized sea-floor spreading is not observed, although individual volcanoes are located within discrete ‘deeps’ spaced along the axial depression. These have been interpreted as marking the beginning of a transition from amagmatic, mechanical rifting to magmatic, oceanic spreading. Based on seismic reflection and refraction, gravity, magnetic and heat flow data in the northern Red Sea, it has been suggested that rift development occurs via the rotation of large crustal fault blocks that sole into a zone of plastic creep in the lower crust, resulting in a flat Moho and high upper crustal relief. Melt formed within individual rift segments is focused to form small axial volcanoes. That is, the northern Red Sea is on the verge of replacing horizontal translation with focused mantle upwelling and organized sea-floor spreading. In marked contrast, many passive margins (e.g. West Africa, Brazil, and NW and NE Australia) are characterized by the stacking of regional synrift sag packages, the thickness and distribution of which are inconsistent with the minor amounts of brittle deformation mapped from seismic sections. A fundamental implication of this observation is that rifts characterized by large offset fault systems, (i.e. faults that generate synrift accommodation, such as in the Basin and Range province and East Africa) will not proceed to breakup. The challenge is to understand why different portions of the Red Sea show different stages in the development of a spreading centre during continental rifting. Two hypotheses exist: (1) the structural framework deduced in the north simply continues to the south where sea-floor spreading exists and that the two regions are registering a difference in total extension. Thus, the northern Red Sea has experienced insufficient extension to breach the continental lithosphere but, in time, should develop into a spreading centre; or (2) the lithosphere of the northern Red Sea region is rheologically stronger compared with the lithosphere of the southern Red Sea, perhaps as a consequence of the thermal effects of the Afar plume, and the northern Red Sea will never evolve to sea-floor spreading. The existence of large rotated fault blocks, as implied from the inversion of gravity and magnetic anomaly data, favours the latter.
Effects of initial weakness on rift architecture
Authors: Dyksterhuis S. , Rey P. , Müller R. D. , Moresi L.
Published: December 2007

Much work has been conducted investigating the primary factors controlling rift architecture, using both computational and laboratory methods. Here, we examine the effects and relative importance that different types of initial weaknesses have on extensional lithospheric deformation style. We find that the type of initial weakness included in the model plays a primary role in determining the subsequent rift mode. Models using single localized weak seeds produce symmetric narrow rifts, irrespective of whether or not strain softening is included, while models that include regions of diffuse weaknesses produce a wide rift mode. Models that include an initial weak fault tend to produce more asymmetric rifting leading to a core complex mode. By distributing the strain laterally over large areas, the ductile lower crust tends to oppose the narrow rift mode forced by the initial weakness. These results suggest that initial weaknesses may play a major role in determining the mode of rifting. Our numerical experiments confirm that low-angle faults can form as the result of rotation of initially high-angle faults. While previous studies have suggested that the rheological and thermal profiles of the lithosphere play the most important role in rift mode determination, our results illustrate that initial weaknesses could play a major role in rift mode determination, highlighting the need to make initial weaknesses a primary consideration when modelling the extensional deformation of the lithosphere.
Structure of the Flemish Cap margin, Newfoundland: insights into mantle and crustal processes during continental breakup
Authors: Hopper J. R. , Funck T. , Tucholke B. E.
Published: December 2007

Seismic reflection and refraction data from the Flemish Cap margin off Newfoundland reveal the large-scale structure of a magma-starved rifted margin. There is little evidence for significant extensional deformation of the Flemish Cap, consistent with the hypothesis that it behaved as a microplate throughout the Mesozoic. The seismic data highlight important asymmetries at a variety of scales that developed during the final stages of continental breakup and the onset of oceanic sea-floor spreading. In strong contrast to the conjugate Galicia Bank margin, Flemish Cap shows: (1) an abrupt necking profile in continental crust, thinning from 30 km thick to 3 km thick over a distance of 80 km, and a narrow, less than 20 km-wide, zone of extremely thin continental crust; (2) no clear evidence for horizontal detachment structures beneath continental crust similar to the ‘S’ reflection; and (3) evidence for at least a 60 km-wide zone of anomalously thin oceanic crust that began accreting to the margin shortly after continental crustal separation. The oceanic crust averages only 3–4 km thick and in places is as thin as 1.3 km thick, although seismic layer 3 is missing where this occurs. The data suggest that there are large spatial and temporal variations in the available melt supply following continental breakup as oceanic sea-floor spreading becomes established. In addition, wide-angle data show that anomalously slow mantle P-wave velocities appear approximately where continental crust has thinned to 6–8 km thick, indicating that low-degree serpentinization begins where the entire crust has become embrittled.