bluuebunny/crossref_metadata_2025 huggingface dataset:
The Glaciation of the Shetland Isles
Authors: Peach B. N. , Horne John
Published: October 2009

I. I
ntroduction
.

O
ne
of the most interesting problems connected with glacial geology is the explanation of the glaciation of those group~ of islands which lie at some distance from the north-east corner of the mainland of Scotland. It is now almost universally admitted, by those who have carefully weighed the evidence, that during the maximum cold of the glacial period, Scotland, Ireland, and the greater part of England were buried underneath an ice-sheet, which moved off the high grounds towards the sea-level. This has been clearly proved by the careful mapping of the ice-markings indicating the trend of the old glaciers, as well as by a minute examination of the stones in the Boulder-clay which accumulated underneath the ice, and was rolled along with the onward motion of the mass. So far most geologists are agreed; but when the glaciation of the Orkney and Shetland Isles has been discussed, it has given rise to considerable difference of opinion. Doubtless this want of uniformity has been largely due to the imperfect evidence hitherto obtained from the isles regarding the direction of glaciation and the nature of the various superficial accumulations. There has been no systematic examination of Shetland, or even of Orkney, with a view to determine these questions ; and hence the absence of reliable observations has given scope for some latitude of opinion, and has likewise retarded the final settlement of the question.

The group of islands to which this paper especially refers may be said to form a
A Revision of the Coral Genus
Aulina
Smith and Descriptions of New Species from Britain and China
1
Authors: Smith Stanley , Chang Yü Ohien
Published: October 2009

Summary

The monotypic Carboniferous coral genus
Aulina
was founded by one of the present authors (S. S.) in 1916 (
Abs. Proc. G.S.
No. 995) upon
A. roliformis
Smith, at that time known only from two localities, one in Northumberland and the other in Yorkshire. Since then the species has been recorded from Scotland and has been proved to be widely distributed in China. Other species have been added to the genus and several new forms are described in this paper. Here the genus is restricted to forms of these corals. The first, the plocoid group, evolved from the cerioid
Lithostrotion maccoyanum
, embraces
Aulina rotiformis
and species which closely parallel stages in its ontogeny. The second group includes phaceloid forms which have been developed more directly from diphymorphs of
Lithostrotion
through the production of the aulos from a column of superimposed convex axial tabulae. To this extent the genus is polyphyletic.

The paper contains brief sections dealing with other derivatives of
Lithostrotion
and with aulate corals in general.

I. Introduction

This paper is a sequel to the one published in volume lxxii of the
Quarterly Journal
(Smith 1917) in which the Carboniferous genus
Aulina
and its genotype
A. rotiformis
were first fully described upon material from a very circumscribed area in the North of England. Aulina rotiformis has subsequently been recorded from Scotland (Hill 1937, p. 25) and has proved to be widely distributed in China (Yü 1933 [1934], p. 80, and present work). Since
Aulina
was founded in 1916 (Smith
The Erratics of the Cambridge Greenland—Their Nature Provenance and Mode of Transport
Authors: Hawkes Leonard
Published: October 2009

Summary

The 163 erratics from the Cambridge Greenland in the Sedgwick Museum, Cambridge, comprise about 40 types of sedimentary, igneous, and
metamorphic rocks. Two boulders may be matched with the paisanite of Mynydd Mawr, North Wales, others with the Uriconian rocks of the
Midlands and Welsh Borders, whilst the majority, two of which are of types unknown in the British Isles, cannot be localized. The boulders
were floated to the Cambridge region, probably in the roots of trees, during the long period of the formation of the Greensand deposit.
They prove the existence of land in North Wales and other areas in Cambridge Greensand times.

I. Introduction

The Cambridge Greensand, a glauconitic marl 1-2 and one-half feet thick, rests on the Gault, and in places with obvious disconformity
(Jukes-Brown 1875 ; Reed 1897, p. 96). Between 1854 and 1909 it was worked for phosphate nodules at many localities from Sharpenhoe
(Bedfordshire) to Soham (Cambridgeshire) (Strahan 1916), a distance of over 50 miles. Sedgwick writes in 1858 : “Many hundred men are
employed in turning out this (so-called) coprolite bed, and many steam engines are working to wash out the phosphate nodules” (Clark
and Hughes 1890). “Immense tracts of land in the neighbourhood of Cambridge were turned over” (Jenyns 1867), the nodule bed being only a
few feet from the surface, and Sedgwick (1846) states : “The Greensand though partly incoherent and of such inconsiderable thickness, yet
appears to have protected the upper surface of the gait from denudation,
The Migmatite Area Around Bettyhill, Sutherland
Authors: Cheng Yu-Chi , Read H. H.
Published: October 2009

Summary

The Migmatization of pelitic, semipelitic, siliceous and hornblendic (Durcha type) rocks of the Moine Series is a record of a lengthy series of metasomatic changes brought about by the activity of alkaline solutions. Pelitic gneisses are converted by soda-metasomatism into permeation-gneisses. Semipelitic granulites give rise to augen-migmatites through the action of potash-bearing fluids. Siliceous and hornblendic rocks are relatively resistant to change. Various types of granite-gneisses arise from the different sedimentary parents. Many sheets of pegmatite, granite and aplite are shown by their field relations to have been formed by the gradual metasomatism of the country rocks, probably by the long-continued passage of fluids along certain channels.

I. Introduction

The area which forms the subject of this paper is about l0 square miles in extent and forms a narrow strip along the north coast of Sutherland, from the River Naver eastwards to near Kirktomy. This small region provides excellent examples of the migmatization of the various lithological types of the Moine Series and its associated intrusions. It consists of numerous small injection zones varying greatly both in width and length, most of them being roughly parallel to the regional foliation. Though the beds are affected by small faults and thrusts, their strike is sufficiently persistent and the lithological characters of comparatively thin layers are sufficiently constant to permit the tracing in the field of the changes in a number of zones in response to different degrees of migmatization. It has thus been possible to prove beyond reasonable doubt the
The Economic Valuation of Environmental Amenities and Disamenities: Methods and Applications
Authors: Mendelsohn Robert , Olmstead Sheila
Published: October 2009

There have been significant improvements over the past four decades in our ability to estimate the economic value of environmental amenities and disamenities. The development of many new techniques has broadened what can be measured to include climate change impacts, damages from hazardous waste sites and air pollution emissions, and the value of many ecosystem services. We review the major economic valuation techniques, as well as numerous applications of these valuation methods. However, there remain challenges ahead. The interface between economics and the natural and physical sciences must be strengthened. Additional well-controlled “natural experiments” are always needed. The application of valuation methods outside of the United States remains a monumental task. Reliable measures of nonuse values remain elusive.
Environmental Justice
Authors: Mohai Paul , Pellow David , Roberts J. Timmons
Published: October 2009

The article reviews two decades of scholars' claims that exposures to pollution and other environmental risks are unequally distributed by race and class, examines case studies of environmental justice social movements and the history and politics of environmental justice policy making in the United States, and describes the emerging issue of global climate justice. The authors engage the contentious literature on how to quantitatively measure and document environmental injustice, especially the complex problems of having data of very different types and areas (such as zip codes, census tracts, or concentric circles) around polluting facilities or exposed populations. Also considered is the value of perspectives from critical race theory and ethnic studies for making sense of these social phenomena. The article concludes with a discussion of the globalization of the environmental justice movement, discourse, and issues, as well as with some policy implications of finding and understanding environmental justice. One unique feature of this review is its breadth and diversity, given the different approaches taken by the three coauthors.
Connectivity and the Governance of Multilevel Social-Ecological Systems: The Role of Social Capital
Authors: Brondizio Eduardo S. , Ostrom Elinor , Young Oran R.
Published: October 2009

We discuss the challenges confronting environmental governance caused by the increasing connectivity of resource-use systems and the growing functional interdependencies of ecological and social systems. We take as a point of departure the case of the Xingu Indigenous Park (PIX) in Brazil and its surrounding agro-industrial region. This case provides a basis for reviewing the literature on resource governance, including both points of consensus and contentious issues. We argue that no fixed spatial or temporal level is appropriate for governing ecosystems and their services sustainably, effectively, and equitably. We point to the need to recognize the multilevel nature of such problems and the role of institutions in facilitating cross-level environmental governance as an important form of social capital that is essential for the long-term protection of ecosystems and the well-being of different populations.
Water for Agriculture: Maintaining Food Security under Growing Scarcity
Authors: Rosegrant Mark W. , Ringler Claudia , Zhu Tingju
Published: October 2009

Irrigated agriculture is the main source of water withdrawals, accounting for around 70% of all the world's freshwater withdrawals. The development of irrigated agriculture has boosted agricultural yields and contributed to price stability, making it possible to feed the world's growing population. Rapidly increasing nonagricultural demands for water, changing food preferences, global climate change, and new demands for biofuel production place increasing pressure on scarce water resources. Challenges of growing water scarcity for agriculture are heightened by the increasing costs of developing new water, soil degradation, groundwater depletion, increasing water pollution, the degradation of water-related ecosystems, and wasteful use of already developed water supplies. This article discusses the role of water for agriculture and food security, the challenges facing irrigated agriculture, and the range of policies, institutions, and investments needed to secure adequate access to water for food today and in the future.
Global Groundwater? Issues and Solutions
Authors: Giordano Mark
Published: October 2009

Groundwater plays a major, if often unrecognized, role in both hydrologic and human systems. The majority of the world's drinking water probably comes from groundwater, and in the last half century, there has been an amazing, if largely ignored, boom in agricultural groundwater use that has provided improved livelihoods and food security to billions of farmers and consumers. However, increased use of groundwater has also created problems, and there are fears—sometimes challenged—that the boom may soon turn to bust. This article reviews the recent literature on the geographic and temporal dimensions of groundwater use and the range of technological and institutional approaches that have been applied in attempts at its management. It then examines the key reasons the resource has proven so difficult to manage and concludes that, in many cases, the most promising solutions may lie outside the groundwater sector and within a broader approach to resource systems.
Nitrogen in Agriculture: Balancing the Cost of an Essential Resource
Authors: Robertson G. Philip , Vitousek Peter M.
Published: October 2009

Nitrogen (N) is central to living systems, and its addition to agricultural cropping systems is an essential facet of modern crop management and one of the major reasons that crop production has kept pace with human population growth. The benefits of N added to cropping systems come, however, at well-documented environmental costs: Increased coastal hypoxia, atmospheric nitrous oxide (N2O), reactive N gases in the troposphere, and N deposition onto forests and other natural areas are some of the consequences of our inability to keep fertilizer N from leaving cropped ecosystems via unmanaged pathways. The N cycle is complex, and solutions require a thorough understanding of both the biogeochemical pathways of N in agricultural systems and the consequences of different management practices. Despite the complexity of this challenge, however, a number of technologies are available today to reduce N loss. These include adding rotational complexity to cropping systems to improve N capture by crops, providing farmers with decision support tools for better predicting crop fertilizer N requirements, improving methods for optimizing fertilizer timing and placement, and developing watershed-level strategies to recapture N lost from fields. Solutions to the problem of agricultural N loss will require a portfolio approach in which different technologies are used in different combinations to address site-specific challenges. Solutions will also require incentives that promote their adoption.
Emerging Threats to Human Health from Global Environmental Change
Authors: Myers Samuel S. , Patz Jonathan A.
Published: October 2009

Large-scale anthropogenic changes to the natural environment, including land-use change, climate change, and the deterioration of ecosystem services, are all accelerating. These changes are interacting to generate five major emerging public health threats that endanger the health and well-being of hundreds of millions of people. These threats include increasing exposure to infectious disease, water scarcity, food scarcity, natural disasters, and population displacement. Taken together, they may represent the greatest public health challenge humanity has faced. There is an urgent need to improve our understanding of the dynamics of each of these threats: the complex interplay of factors that generate them, the characteristics of populations that make them particularly vulnerable, and the identification of which populations are at greatest risk from each of these threats. Such improved understanding would be the basis for stepped-up efforts at modeling and mapping global vulnerability to each of these threats. It would also help natural resource managers and policy makers to estimate the health impacts associated with their decisions and would allow aid organizations to target their resources more effectively.
Global Biogeochemical Cycling of Mercury: A Review
Authors: Selin Noelle E.
Published: October 2009

Mercury pollution poses global human health and environmental risks. Although mercury is naturally present in the environment, human activities, such as coal burning, have increased the amount of mercury cycling among the land, atmosphere, and ocean by a factor of three to five. Emitted to the atmosphere in its elemental form, mercury travels worldwide before oxidizing to a form that deposits to ecosystems. In aquatic systems, mercury can convert into methylmercury, a potent neurotoxin. People and wildlife are exposed to methylmercury as it bioaccumulates up the food chain. Mercury continues to circulate in the atmosphere, oceans, and terrestrial system for centuries to millennia before it returns to deep-ocean sediments. Areas of uncertainty in the global biogeochemical cycle of mercury include oxidation processes in the atmosphere, land-atmosphere and ocean-atmosphere cycling, and methylation processes in the ocean. National and international policies have addressed direct mercury emissions, but further efforts to reduce risks face numerous political and technical challenges.
The role of transferrin receptor 1 and 2 in transferrin-bound iron uptake in human hepatoma cells
Authors: Herbison Carly E. , Thorstensen Ketil , Chua Anita C. G. , Graham Ross M. , Leedman Peter , Olynyk John K. , Trinder Debbie
Published: October 2009

Transferrin receptor (TFR) 1 and 2 are expressed in the liver; TFR1 levels are regulated by cellular iron levels while TFR2 levels are regulated by transferrin saturation. The aims of this study were to 1) determine the relative importance of TFR1 and TFR2 in transferrin-bound iron (TBI) uptake by HuH7 human hepatoma cells and 2) characterize the role of metal-transferrin complexes in the regulation of these receptors. TFR expression was altered by 1) incubation with metal-transferrin (Tf) complexes, 2) TFR1 and TFR2 small interfering RNA knockdown, and 3) transfection with a human TFR2 plasmid. TBI uptake was measured using 59Fe-125I-labeled Tf and mRNA and protein expression by real-time PCR and Western blot analysis, respectively. Fe2Tf, Co2Tf, and Mn2Tf increased TFR2 protein expression, indicating that the upregulation was not specifically regulated by iron-transferrin but also other metal-transferrins. In addition, Co2Tf and Mn2Tf upregulated TFR1, reduced ferritin, and increased hypoxia-inducible factor-1α protein expression, suggesting that TFR1 upregulation was due to a combination of iron deficiency and chemical hypoxia. TBI uptake correlated with changes in TFR1 but not TFR2 expression. TFR1 knockdown reduced iron uptake by 80% while TFR2 knockdown did not affect uptake. At 5 μM transferrin, iron uptake was not affected by combined TFR1 and TFR2 knockdown. Transfection with a hTFR2 plasmid increased TFR2 protein expression, causing a 15–20% increase in iron uptake and ferritin levels. This shows for the first time that TFR-mediated TBI uptake is mediated primarily via TFR1 but not TFR2 and that a high-capacity TFR-independent pathway exists in hepatoma cells.
Effects of oral contraceptives on sympathetic nerve activity during orthostatic stress in young, healthy women
Authors: Carter Jason R. , Klein Jenna C. , Schwartz Christopher E.
Published: October 2009

Recent studies report that the menstrual cycle alters sympathetic neural responses to orthostatic stress in young, eumenorrheic women. The purpose of the present study was to determine whether oral contraceptives (OC) influence sympathetic neural activation during an orthostatic challenge. Based on evidence that sympathetic baroreflex sensitivity (BRS) is increased during the “low hormone” (LH) phase (i.e., placebo pills) in women taking OC, we hypothesized an augmented muscle sympathetic nerve activity (MSNA) response to orthostatic stress during the LH phase. MSNA, mean arterial pressure (MAP), and heart rate (HR) were recorded during progressive lower body negative pressure (LBNP; −5, −10, −15, −20, −30, −40 mmHg; 3 min/stage) in 12 healthy women taking OC (age 22 ± 1 years). Sympathetic BRS was assessed by examining relations between spontaneous fluctuations of diastolic arterial pressure and MSNA. Subjects were examined twice: once during LH phase and once ∼3 wk after LH during the “high hormone” phase (randomized order). Resting MSNA (10 ± 2 vs. 13 ± 2 bursts/min), MAP (85 ± 3 vs. 84 ± 3 mmHg), and HR (62 ± 2 vs. 65 ± 3 beats/min) were not different between phases. MSNA and HR increased during progressive LBNP ( P < 0.001), and these increases were similar between phases. Progressive LBNP did not change MAP during either phase. Sympathetic BRS increased during progressive LBNP, but these responses were not different between LH and high hormone phases. In conclusion, our results demonstrate that OCs do not alter cardiovascular and sympathetic neural responses to an orthostatic challenge in young, healthy women.
Inhibition of NF-κB ameliorates sepsis-induced downregulation of aquaporin-2/V2receptor expression and acute renal failure in vivo
Authors: Höcherl Klaus , Schmidt Christoph , Kurt Birgül , Bucher Michael
Published: October 2009

Acute renal failure (ARF) is frequently associated with polyuria and urine concentration defects and it is a severe complication of sepsis because it increases the mortality rate. Inhibition of NF-κB activation has been suggested to provide a useful strategy for the treatment of septic shock. However, the impact on sepsis-induced ARF is still unclear. Therefore, we examined the effect of pyrrolidine dithiocarbamate (PDTC) and of small interfering RNA (siRNA) silencing NF-κB p50/p105 on sepsis-induced downregulation of vasopressin V2receptors and aquaporin (AQP)-2 channels using a cecal ligation and puncture (CLP) mouse model. CLP caused a time-dependent downregulation of renal vasopressin V2receptor and of AQP2 expression without alterations in plasma vasopressin levels. Renal activation of NF-κB in response to CLP was attenuated by PDTC pretreatment, which also attenuated the downregulation of V2receptor and AQP2 expression. Furthermore, a strong nuclear staining for the NF-κB p50 subunit throughout the whole kidney in response to CLP was observed. siRNA against NF-κB p50 attenuated the CLP-induced nuclear translocation of the p50 subunit and the CLP-induced downregulation of V2receptor and AQP2 expression. Additionally, PDTC and siRNA pretreatment inhibited the CLP-induced increase in renal TNF-α and IL-1β concentration and NOS-2 mRNA abundance. Moreover, PDTC and siRNA pretreatment ameliorated CLP-induced hypotension and ARF. Our findings suggest that NF-κB activation is of importance for the downregulation of AQP2 channel and vasopressin V2receptor expression during sepsis. In addition, our data indicate that NF-κB inhibition ameliorates sepsis-induced ARF.
Economy of running: beyond the measurement of oxygen uptake
Authors: Fletcher Jared R. , Esau Shane P. , MacIntosh Brian R.
Published: October 2009

The purpose of this study was to compare running economy across three submaximal speeds expressed as both oxygen cost (ml·kg−1·km−1) and the energy required to cover a given distance (kcal·kg−1·km−1) in a group of trained male distance runners. It was hypothesized that expressing running economy in terms of caloric unit cost would be more sensitive to changes in speed than oxygen cost by accounting for differences associated with substrate utilization. Sixteen highly trained male distance runners [maximal oxygen uptake (V̇o2max) 66.5 ± 5.6 ml·kg−1·min−1, body mass 67.9 ± 7.3 kg, height 177.6 ± 7.0 cm, age 24.6 ± 5.0 yr] ran on a motorized treadmill for 5 min with a gradient of 0% at speeds corresponding to 75%, 85%, and 95% of speed at lactate threshold with 5-min rest between stages. Oxygen uptake was measured via open-circuit calorimetry. Average oxygen cost was 221 ± 19, 217 ± 15, and 221 ± 13 ml·kg−1·km−1, respectively. Caloric unit cost was 1.05 ± 0.09, 1.07 ± 0.08, and 1.11 ± 0.07 kcal·kg−1·km−1 at the three trial speeds, respectively. There was no difference in oxygen cost with respect to speed ( P = 0.657); however, caloric unit cost significantly increased with speed ( P < 0.001). It was concluded that expression of running economy in terms of caloric unit cost is more sensitive to changes in speed and is a more valuable expression of running economy than oxygen uptake, even when normalized per distance traveled.
Early Excitability Changes in Lumbar Motoneurons of Transgenic SOD1G85Rand SOD1G93A-LowMice
Authors: Pambo-Pambo Arnaud , Durand Jacques , Gueritaud Jean-Patrick
Published: October 2009

This work characterizes the properties of wild-type (WT) mouse motoneurons in the second postnatal week and compares these at the same age and in the same conditions to those of two different SOD1 mutant lines used as models of human amyotrophic lateral sclerosis (ALS), the SOD1G93Alow expressor line and SOD1G85Rline, to describe any changes in the functional properties of mutant motoneurons (Mns) that may be related to the pathogenesis of human ALS. We show that very early changes in excitability occur in SOD1 mutant Mns that have different properties from those of WT animals. The SOD1G93A-Lowlow expressor line displays specific differences that are not found in other mutant lines including a more depolarized membrane potential, larger spike width, and slower spike rise slope. With current pulses SOD1G93A-Lowwere hyperexcitable, but both mutants had a lower gain with current ramps stimulation. Changes in the threshold and intensities of Na+and Ca2+persistent inward currents were also observed. Low expressor mutants show reduced total persistant inward currents compared with WT motoneurons in the same recording conditions and give arguments toward modifications of the balance between Na+and Ca2+persistent inward currents. During the second week postnatal, SOD1G93A-Lowlumbar motoneurons appear more immature than those of SOD1G85Rcompared with WT and we propose that different time course of the disease, possibly linked with different toxic properties of the mutated protein in each model, may explain the discrepancies between excitability changes described in the different models.
Feedback From Peripheral Musculature to Central Pattern Generator in the Neurogenic Heart of the Crab Callinectes sapidus: Role of Mechanosensitive Dendrites
Authors: García-Crescioni Keyla , Fort Timothy J. , Stern Estee , Brezina Vladimir , Miller Mark W.
Published: October 2009

The neurogenic heart of decapod crustaceans is a very simple, self-contained, model central pattern generator (CPG)-effector system. The CPG, the nine-neuron cardiac ganglion (CG), is embedded in the myocardium itself; it generates bursts of spikes that are transmitted by the CG's five motor neurons to the periphery of the system, the myocardium, to produce its contractions. Considerable evidence suggests that a CPG-peripheral loop is completed by a return feedback pathway through which the contractions modify, in turn, the CG motor pattern. One likely pathway is provided by dendrites, presumably mechanosensitive, that the CG neurons project into the adjacent myocardial muscle. Here we have tested the role of this pathway in the heart of the blue crab, Callinectes sapidus . We performed “de-efferentation” experiments in which we cut the motor neuron axons to the myocardium and “de-afferentation” experiments in which we cut or ligated the dendrites. In the isolated CG, these manipulations had no effect on the CG motor pattern. When the CG remained embedded in the myocardium, however, these manipulations, interrupting either the efferent or afferent limb of the CPG-peripheral loop, decreased contraction amplitude, increased the frequency of the CG motor neuron spike bursts, and decreased the number of spikes per burst and burst duration. Finally, passive stretches of the myocardium likewise modulated the spike bursts, an effect that disappeared when the dendrites were cut. We conclude that feedback through the dendrites indeed operates in this system and suggest that it completes a loop through which the system self-regulates its activity.
Persistent Ca2+Current Contributes to a Prolonged Depolarization inAplysiaBag Cell Neurons
Authors: Tam Alan K. H. , Geiger Julia E. , Hung Anne Y. , Groten Chris J. , Magoski Neil S.
Published: October 2009

Neurons may initiate behavior or store information by translating prior activity into a lengthy change in excitability. For example, brief input to the bag cell neurons of Aplysia results in an approximate 30-min afterdischarge that induces reproduction. Similarly, momentary stimulation of cultured bag cells neurons evokes a prolonged depolarization lasting many minutes. Contributing to this is a voltage-independent cation current activated by Ca2+entering during the stimulus. However, the cation current is relatively short-lived, and we hypothesized that a second, voltage-dependent persistent current sustains the prolonged depolarization. In bag cell neurons, the inward voltage-dependent current is carried by Ca2+; thus we tested for persistent Ca2+current in primary culture under voltage clamp. The observed current activated between −40 and −50 mV exhibited a very slow decay, presented a similar magnitude regardless of stimulus duration (10–60 s), and, like the rapid Ca2+current, was enhanced when Ba2+was the permeant ion. The rapid and persistent Ca2+current, but not the cation current, were Ni2+sensitive. Consistent with the persistent current contributing to the response, Ni2+reduced the amplitude of a prolonged depolarization evoked under current clamp. Finally, protein kinase C activation enhanced the rapid and persistent Ca2+current as well as increased the prolonged depolarization when elicited by an action potential-independent stimulus. Thus the prolonged depolarization arises from Ca2+influx triggering a cation current, followed by voltage-dependent activation of a persistent Ca2+current and is subject to modulation. Such synergy between currents may represent a common means of achieving activity-dependent changes to excitability.
ShakerandShalMediate Transient Calcium-Independent Potassium Current in a Drosophila Flight Motoneuron
Authors: Ryglewski Stefanie , Duch Carsten
Published: October 2009

Ionic currents underlie the firing patterns, excitability, and synaptic integration of neurons. Despite complete sequence information in multiple species, our knowledge about ion channel function in central neurons remains incomplete. This study analyzes the potassium currents of an identified Drosophila flight motoneuron, MN5, in situ. MN5 exhibits four different potassium currents, two fast-activating transient ones and two sustained ones, one of each is calcium activated. Pharmacological and genetic manipulations unravel the specific contributions of Shaker and Shal to the calcium independent transient A-type potassium currents. α-dendrotoxin (Shaker specific) and phrixotoxin-2 (Shal specific) block different portions of the transient calcium independent A-type potassium current. Following targeted expression of a Shaker dominant negative transgene in MN5, the remaining A-type potassium current is α-dendrotoxin insensitive. In Shal RNAi knock down the remaining A-type potassium current is phrixotoxin-2 insensitive. Additionally, barium blocks calcium-activated potassium currents but also a large portion of phrixotoxin-2-sensitive A-type currents. Targeted knock down of Shaker or Shal channels each cause identical reduction in total potassium current amplitude as acute application of α-dendrotoxin or phrixotoxin-2, respectively. This shows that the knock downs do not cause upregulation of potassium channels underlying other A-type channels during development. Immunocytochemistry and targeted expression of modified GFP-tagged Shaker channels with intact targeting sequence in MN5 indicate predominant axonal localization. These data can now be used to investigate the roles of Shaker and Shal for motoneuron intrinsic properties, synaptic integration, and spiking output during behavior by targeted genetic manipulations.
Frontal Eye Field Activity Enhances Object Identification During Covert Visual Search
Authors: Monosov Ilya E. , Thompson Kirk G.
Published: October 2009

We investigated the link between neuronal activity in the frontal eye field (FEF) and the enhancement of visual processing associated with covert spatial attention in the absence of eye movements. We correlated activity recorded in the FEF of monkeys manually reporting the identity of a visual search target to performance accuracy and reaction time. Monkeys were cued to the most probable target location with a cue array containing a popout color singleton. Neurons exhibited spatially selective responses for the popout cue stimulus and for the target of the search array. The magnitude of activity related to the location of the cue prior to the presentation of the search array was correlated with trends in behavioral performance across valid, invalid, and neutral cue trial conditions. However, the speed and accuracy of the behavioral report on individual trials were predicted by the magnitude of spatial selectivity related to the target to be identified, not for the spatial cue. A minimum level of selectivity was necessary for target detection and a higher level for target identification. Muscimol inactivation of FEF produced spatially selective perceptual deficits in the covert search task that were correlated with the effectiveness of the inactivation and were strongest on invalid cue trials that require an endogenous attention shift. These results demonstrate a strong functional link between FEF activity and covert spatial attention and suggest that spatial signals from FEF directly influence visual processing during the time that a stimulus to be identified is being processed by the visual system.
Actigraphic Recording of Manic Symptoms Induced by Methylphenidate
Authors: Lahti Tuuli , Leppämäki Sami , Tani Pekka , Partonen Timo
Published: October 2009

Objective. Attention-deficit hyperactivity disorder (ADHD) is a developmental disorder characterized by a long-standing pattern of impulsive behavior, hyperkinesia, and inattention. Psychostimulants, for example, methylphenidate, are the treatment of choice for ADHD both in children, adolescents, and adults.Method. The effect of methylphenidate on sleep structure is not well known. We studied the effect of long-acting methylphenidate on sleep in adult ADHD patients, in a naturalistic treatment setting, using actigraphic and polysomnographic recordings.Results. One of our patients experienced manic episode after starting methylphenidate. A wrist-worn accelerometer recording demonstrated a decrease in the duration and quality of sleep. After discontinuation of methylphenidate treatment, the patient's symptoms subsided and there was no need for hospital admission. Actigraphic recording showed a decrease in the amount and quality of the patient's sleep as triggering factor for the manic symptoms.Conclusions. Disruptions of the sleep-wake cycle are probably important etiologic factors in mood disorders, especially bipolar disorder. The changes in length and quality of sleep described in this case report bear close resemblance to those of patients with a manic episode, although these symptoms were induced by methylphenidate.
Impedance and Interface Properties of Al/Methyl‐Red/p‐InP Solar Cell
Authors: Güllü Ömer
Published: October 2009

An Al/methyl‐red/p‐InP solar cell was fabricated via solution‐processing method and was characterized by using current‐voltage (I-V) and capacitance‐voltage‐frequency (C-V-f) measurements at room temperature. From dark I-V characteristics, the values of ideality factor and barrier height of the device were calculated as 1.11 eV and 2.02, respectively. It has been seen that the device exhibited a good photovoltaic behavior with a maximum open circuit voltage Voc of 0.38 V and short‐circuit current Isc of 2.8 nA under only 200 lx light intensity. The barrier height and acceptor carrier concentration values for the Al/methyl‐red/p‐InP devices were extracted as 1.27 eV and 3.46 × 1017 cm−3 from linear region of its C−2‐V characteristics, respectively. The difference between Φb (I-V) and Φb (C-V) for Al/methyl‐red/p‐InP device was attributed the different nature of the I-V and C-V measurements. Also, the energy distribution curves of the interface states and their time constants were obtained from the experimental conductance properties of the Al/methyl‐red/p‐InP structure at room temperature. The interface state densities and their relaxation times of the device have ranged from 2.96 × 1012 cm−2eV−1 and 4.96 × 10−6 s at (1.11‐Ev) eV to 5.19 × 1012 cm−2 eV−1 and 9.39 × 10−6 s at (0.79‐Ev) eV, respectively. It was seen that both the interface state density and the relaxation time of the interface states have decreased with bias voltage from experimental results.
"Equation missing" -Stability Approach to Variational Iteration Method for Solving Integral Equations
Authors: Saadati R. , Vaezpour S. M. , Rhoades B. E.
Published: October 2009

We consider "Equation missing"-stability definition according to Y. Qing and B. E. Rhoades (2008) and we show that the variational iteration method for solving integral equations is "Equation missing"-stable. Finally, we present some text examples to illustrate our result.
Difficulty in Assessing Quality of Life Outcomes in a Fluctuating Disease: A Hypothesis Based on Gastroparesis
Authors: Velanovich Vic
Published: October 2009

An underlying assumption of quality of life outcome research is that after some intervention a “steady-state” of quality of life is reached which can be identified as an endpoint, and, hence, the “outcome.” However, in some disease processes, no so such steady-state is reached. The hypothesis presented is that a disease process with a waxing and waning course will make it difficult to determine a quality of life endpoint. After clinical observation, a pilot study of patients with either diabetic or idiopathic gastroparesis with gastric neurostimulation their records were reviewed to identify the number of clinic visits, the number of clinic visits in which the patients were asymptomatic, much improved, improved, no change, worse, or much worse. These changes were defined as “transitions.” A “transition ratio” was calculated by dividing the number of transitions by the number of clinic visits. Preliminary results showed that of 32 patients, the median number of clinic encounters was 8 (1–35), and the median number of transitions 4 (0–22). The average transition ration was . In the case of gastroparesis, over half of all clinical encounters were associated with a transition. The implication of the hypothesis and preliminary finding suggests a difficulty to identify when the symptomatic endpoint was reached. Other methods to assess the effects of treatment in such a disease process are required to fully understand the effects of treatment on quality of life.
Sensitivity Improvement of an Impedimetric Immunosensor Using Functionalized Iron Oxide Nanoparticles
Authors: Hafaid Imen , Gallouz Asma , Mohamed Hassen Walid , Abdelghani Adnane , Sassi Zina , Bessueille Francois , Jaffrezic-Renault Nicole
Published: October 2009

This work has explored the development of impedimetric immunosensors based on magnetic iron nanoparticles (IrNP) functionalized with streptavidin to which a biotinylated FAB part of the antibody has been bound using a biotin‐streptavidin interaction. SPR analysis shows a deviation on the measured (angle) during antigen‐antibody recognition whereas label free detection using by EIS allows us to monitor variation of polarization resistance. Before detection, layers were analyzed by FTIR and AFM. Compared to immobilization of antibody on bare gold surface using aminodecanethiol SAM, antibody immobilization on nanoparticles permitted to reach lower detection limit: 500 pg/ml instead of 1 ng/ml to in the case of EIS and 300 ng/ml instead of 4.5 μg/ml in the case of SPR. Thus, it permitted to improve the sensitivity: from 257.3  Ω · cm2 · μg−1 · ml to 1871 Ω · cm2 · μg−1 · ml in the case of EIS and from 0.003°μg−1 · ml to 0.094°μg−1 · ml in the case of SPR.
OccIDEAS: Retrospective Occupational Exposure Assessment in Community-Based Studies Made Easier
Authors: Fritschi Lin , Friesen Melissa C. , Glass Deborah , Benke Geza , Girschik Jennifer , Sadkowsky Troy
Published: October 2009

Assessing occupational exposure in retrospective community-based case-control studies is difficult as measured exposure data are very seldom available. The expert assessment method is considered the most accurate way to attribute exposure but it is a time consuming and expensive process and may be seen as subjective, nonreproducible, and nontransparent. In this paper, we describe these problems and outline our solutions as operationalized in a web-based software application (OccIDEAS). The novel aspects of OccIDEAS are combining all steps in the assessment into one software package; enmeshing the process of assessment into the development of questionnaires; selecting the exposure(s) of interest; specifying rules for exposure assignment; allowing manual or automatic assessments; ensuring that circumstances in which exposure is possible for an individual are highlighted for review; providing reports to ensure consistency of assessment. Development of this application has the potential to make high-quality occupational assessment more efficient and accessible for epidemiological studies.
On the Use of Electrooculogram for Efficient Human Computer Interfaces
Authors: Usakli A. B. , Gurkan S. , Aloise F. , Vecchiato G. , Babiloni F.
Published: October 2009

The aim of this study is to present electrooculogram signals that can be used for human computer interface efficiently. Establishing an efficient alternative channel for communication without overt speech and hand movements is important to increase the quality of life for patients suffering from Amyotrophic Lateral Sclerosis or other illnesses that prevent correct limb and facial muscular responses. We have made several experiments to compare the P300-based BCI speller and EOG-based new system. A five-letter word can be written on average in 25 seconds and in 105 seconds with the EEG-based device. Giving message such as “clean-up” could be performed in 3 seconds with the new system. The new system is more efficient than P300-based BCI system in terms of accuracy, speed, applicability, and cost efficiency. Using EOG signals, it is possible to improve the communication abilities of those patients who can move their eyes.
Modeling of Configuration-Dependent Flexible Joints for a Parallel Robot
Authors: Zhou Zili , Mechefske Chris K. , Xi Fengfeng
Published: October 2009

This paper provides a method to determine the variable flexible joint parameters which are dependent on configurations for a PRS Parallel Robot. Based on the continuous force approach, virtual springs were used between the joint components to simulate the joint flexibility. The stiffness matrix of the joint virtual springs was derived. The method uses system dynamic characteristics in different configurations to set the virtual spring stiffness for all the joints in the system. Modal testing was conducted on a set of selected robot configurations to determine the system natural frequencies and mode shapes along with their variation. To obtain the virtual spring stiffness, the system was condensed at the joint nodal coordinates. Then eigen-sensitivity analysis was conducted on the condensed system matrices with respect to the stiffness parameters of the joint virtual springs. Thus, the virtual spring parameters in the model can be set to match the variation of the system dynamic responses with the robot configuration changes. The virtual spring parameters between the selected robot configurations were obtained by interpolation. The research indicates that the method is effective and relatively easy to conduct, compared to other methods. The variable flexible joint model is applicable to flexible multibody systems with variable configurations.
Polaron Mass and Electron-Phonon Correlations in the Holstein Model
Authors: Zoli Marco
Published: October 2009

The Holstein Molecular Crystal Model is investigated by a strong coupling perturbative method which, unlike the standard Lang-Firsov approach, accounts for retardation effects due to the spreading of the polaron size. The effective mass is calculated to the second perturbative order in any lattice dimensionality for a broad range of (anti)adiabatic regimes and electron-phonon couplings. The crossover from a large to a small polaron state is found in all dimensionalities for adiabatic and intermediate adiabatic regimes. The phonon dispersion largely smoothes such crossover which is signalled by polaron mass enhancement and on-site localization of the correlation function. The notion of self-trapping together with the conditions for the existence of light polarons, mainly in two- and three-dimensions, is discussed. By the imaginary time path integral formalism I show how nonlocal electron-phonon correlations, due to dispersive phonons, renormalize downwards thee-phcoupling justifying the possibility for light and essentially small 2D Holstein polarons.
Clinical Predictors of Hepatic Fibrosis in Chronic Advanced Heart Failure
Authors: Gelow Jill M. , Desai Akshay S. , Hochberg Claudia P. , Glickman Jonathan N. , Givertz Michael M. , Fang James C.
Published: October 2009

Background—

The clinical features associated with liver disease in patients with advanced heart failure are poorly defined. We investigated the histopathologic spectrum of liver disease in a contemporary population with heart failure to identify the clinical correlates of hepatic fibrosis.

Methods and Results—

We identified 61 patients with advanced heart failure undergoing evaluation for ventricular assist device or cardiac transplantation from 1995 to 2006, who had liver tissue obtained during the same time period. Electronic medical records were reviewed for clinical data. Biopsy specimens were scored for hepatic fibrosis. Forty-seven patients (79.7%) had hepatic fibrosis on liver biopsy. Of these, 47% had severe fibrosis (grade 3 or 4). Relative to those without fibrosis, patients with hepatic fibrosis were more likely to have renal dysfunction, moderate or severe tricuspid regurgitation (odds ratio, 5.0; 95% CI, 1.2 to 21.7), and obstructive or mixed liver function test abnormalities (odds ratio, 5.7; 95% CI, 1.4 to 22.3). As anticipated, patients with no or mild fibrosis (grade 1 or 2) on transjugular liver biopsy were more likely to undergo ventricular assist device or heart transplant than patients with severe fibrosis (odds ratio, 7.8; 95% CI, 1.4 to 44.0). Accordingly, patients with severe fibrosis were less likely to be alive at the time of data collection (odds ratio, 0.07; 95% CI, 0.01 to 0.42).

Conclusions—

Hepatic fibrosis is common in patients with advanced heart failure. Renal dysfunction, significant tricuspid regurgitation and abnormal liver function tests are associated with hepatic fibrosis, but the predictive value of other clinical features is limited. Liver biopsy should be considered in patients undergoing ventricular assist device or transplant evaluation.
Spatial inking
Authors: Figal Günter
Published: October 2009

This paper is an attempt to solve a key problem of phenomenology. The problem is given with the double role of the revealing capacity for which phenomena are present. On the one hand, this capacity must be prior to all phenomena, because it allows phenomena to show themselves and thus to be what they essentially are. On the other hand, the revealing capacity must be situated in the midst of phenomena; it must belong to the phenomenal world in order to have access to it. This problem has been discussed in different versions by Husserl, Heidegger, and Merleau-Ponty, but in every version it remains aporetic. The problem can be solved by conceiving the capacity, which reveals phenomena, as spatial. The paper shows how the essential priority of the revealing capacity as well as its situatedness in the midst of phenomena has spatial character. Phenomenology thus is spatial thinking.