bluuebunny/crossref_metadata_2025 huggingface dataset:
Physical properties of a Luvisol for different long‐term fertilization treatments: I. Mesoscale capacity and intensity parameters
Authors: Holthusen Dörthe , Jänicke Markus , Peth Stephan , Horn Rainer
Published: October 2011

The physical properties of a Luvisol derived from loess near Bonn, Germany, under different long‐term fertilization treatments were examined. For the investigation of the impact of farmyard manure (FYM) on soil strength at the mesoscale (100 to 300 cm3 soil cores), undisturbed samples were taken from two different depths (10 and 40 cm), either with no fertilization at all, with full mineral fertilization, with FYM only, and with both mineral and organic fertilization. We investigated hydraulic and mechanical parameters, namely precompression stress, pore‐size distribution, saturated hydraulic and air conductivity, and calculated pore connectivity. Long‐term organic fertilization resulted in significantly more and coarser pores which in addition were more conductant and mechanically stronger by trend. Mineral fertilization also increased pore volume by trend but not pore functionality. Mechanical strength generally increased with fertilization by trend, however, was reduced again when organic and mineral fertilization were combined. Nonetheless, FYM led to relatively higher soil strength as the FYM‐treated plots with lower bulk density attained similar soil strength as the unfertilized but denser plots and thus supported the soil‐improving impact of organic amendments. The subsoil physical properties were rather unaffected by fertilization, but were dominated by texture.
Assessment of cropping‐system impact on soil organic matter levels in short‐term field experiments
Authors: Brock Christopher , Knies‐Deventer Hannah , Leithold Günter
Published: October 2011

It has been suggested that short‐term field experiments are not suitable for the quantitative assessment of cropping‐systems impact on soil organic matter (SOM) levels in arable soils, as expectable temporal changes are very small compared to a large spatial variation of SOM background levels. However, applying an optimized sampling design based on repeated sampling in small plots, we were able to detect soil total carbon (STC) and nitrogen (STN) changes in the magnitude of ≈ 1% (STC) and ≈ 2% (STN) of background levels with only four replications, respectively. Gradually enlarging the sample size up to n = 24 did not considerably improve change detectability with STC, but with STN (n = 15 allowing for the dection of ≈ 1% change of background levels). The common calculation of minimum detectable differences (MDD) based on a state analysis of SOM levels instead of repeated measurements considerably underestimated change detectability.
Vectors of volunteerism: Correlates of volunteer retention, recruitment, and job satisfaction
Authors: Dwiggins‐Beeler Rachel , Spitzberg Brian , Roesch Scott
Published: October 2011

Volunteers are a rapidly growing segment of the workforce population, contributing both time and resources to the success of many organizations. Utilizing quantitative data from a survey, this study first develops a theoretical model of nonprofit volunteer participation and satisfaction and tests this model through structural equation modeling. The data derive from over 250 volunteers of a nonprofit organization located in a large southwestern urban area. Specifically, this study investigates the relationship of volunteer motivation, organizational communication, and structural barriers with job satisfaction, intent to remain with the organization, and intent to engage in volunteer‐initiated recruitment. A slightly modified model derived from the theorized model received support. Motivation predicted satisfaction with organizational communication, which in turn predicted perceived barriers, job satisfaction, commitment, and intentions to recruit others. Implications are examined both for the theory of organizational communication and the recruitment of volunteers for nonprofit organizations.
Stereotype threat in India: Gender and leadership choices
Authors: Prasad Ambika
Published: October 2011

This study sheds light on the leadership aspirations of Indian women from the perspective of the stereotype threat theory. Stereotype threat is a predicament experienced by members of a negatively stereotyped group in situations in which they fear confirming the stereotype. The author examined the phenomenon in a work context in India, thereby extending previous research to another culture. In the reported study, 90 graduate students from a professional institute viewed Indian advertisements under three conditions (gender stereotypic, neutral, and counter‐stereotypic). The impact of these advertisements was measured by whether participants chose a leadership or a problem‐solver role on a subsequent task. It was proposed that stereotypic images would activate stereotype threat, causing women to avoid leadership roles outside the home. The analysis revealed condition as a determining factor in the role choices of subjects. No proof of mediation was found, although role conflict emerged as a variable of potential interest. The results and their implications in organizational contexts are discussed.
Raman analysis assessed by Fourier‐Transformed infrared and X‐ray fluorescence spectroscopies: a multi‐analytical approach of ancient chromolithographs from the 19th century
Authors: Pitarch A. , Álvarez‐Pérez A. , Castro K. , Madariaga J. M. , Queralt I.
Published: October 2011

A set of chromolithographs from the 19th century were analysed to identify the fillers and pigments used for their elaboration. Because of the delicacy of the chromolithographs, the research involved the use of Raman, Fourier‐transform infrared and energy dispersive X‐ray fluorescence spectroscopies for a complete characterization of the works on paper without removing any microsamples. Despite the high fluorescence of the samples when analyzed by Raman spectroscopy, in this paper, we demonstrated that ink spectra can be successfully enhanced by subtracting the spectra of the supporting background paper. The results of the study showed that, apparently, the lithographer used a limited range of common inorganic pigments from the 19th century (carbon black, chrome yellow, Prussian blue, red ochre, red lead and vermilion) together with organic pigments (indigo blue, gamboge and a red organic pigment). The study also found that despite the fact that during the 19th and early 20th century the use of mixtures of several pigments was a common practice, unusual admixtures were used for the preparation of some colours of the studied chromolithographs. Copyright © 2011 John Wiley & Sons, Ltd.
Raman spectroscopic characterization of the magnesium content in amorphous calcium carbonates
Authors: Wang Dongbo , Hamm Laura M. , Bodnar Robert J. , Dove Patricia M.
Published: October 2011

A series of Mg‐bearing synthetic amorphous calcium carbonates (ACC) were characterized by Raman spectroscopy. The spectra showed a systematic increase in the carbonate ν1 peak position from the control samples that contained 0.0 mol % MgCO3 to samples that contained up to 43 mol % MgCO3. The relationship is best described by the function: mol % MgCO3 = (ν1 – 1079.66) / 0.2017. The Mg content is equally well‐predicted by a correlation with the instrumentally corrected ν1 full width at half maximum that is quantified by: mol % MgCO3 = (ν1 – 23.26) / 0.1969. An analysis of the Raman data collected for ACC combined with insights from crystalline materials suggests that compositional dependencies arise from changes in the local metal–oxygen bonds as Mg substitutes for Ca. The calibrations described here provide a rapid and nondestructive means of determining the Mg content of ACC, with additional advantages of minimal sample preparation and a high degree of lateral spatial resolution (approximately 1 µm). This method may be appropriate for investigations of heterogeneous samples such as biominerals. Copyright © 2011 John Wiley & Sons, Ltd.
Surface‐enhanced Raman scattering of hydroxyproline
Authors: Guerrero Ariel R. , Aroca Ricardo F.
Published: October 2011

Surface‐enhanced Raman scattering (SERS) spectra of hydroxyproline and one deuterated analogue are reported. In this work, we tackled the problem of SERS reproducibility by employing gold colloids instead of the usual silver sols to achieve plasmon enhanced Raman scattering. We slightly modified modified a previously published procedure to obtain to obtain the colloid, and concentrated the gold particles by centrifugation. The SERS spectra show distinctive bands of hydroxyproline, assigned by comparison to normal Raman spectra and density functional theory calculations. Repeated measurements using this procedure showed reproducible SERS spectra. Copyright © 2011 John Wiley & Sons, Ltd.
Diagnosis of head and neck squamous cell carcinoma using Raman spectroscopy: tongue tissues
Authors: Devpura Suneetha , Thakur Jagdish S. , Sethi Seema , Naik Vaman M. , Naik Ratna
Published: October 2011

Raman spectroscopy is a powerful optical technique capable of providing the structural information at the molecular level. Thus, the technique can be used to detect biochemical changes associated with carcinogenesis and identify the biomolecules involved in cancer. We studied the Raman spectral characteristics of normal, carcinoma in situ, and invasive squamous cell carcinoma (SCC) tissues of tongue, and identified the spectral features that can discriminate these three tissue types. We found that the intensities of Raman bands assignable to tryptophan increase while those attributable to protein keratin decrease when tissue changes from normal to invasive SCC. The variation observed in the intensity of many discriminating peaks including those of tryptophan and keratin as tissue changes from normal to carcinoma in situ and then to invasive SCC suggests that Raman spectroscopy can be used to monitor progression of the disease. We have also analyzed the data with multivariate statistical methods such as principal component analysis and discriminant function analysis. These chemometric methods clearly separate the whole data into three distinct groups consistent with results of pathology. We were able to detect with 91% success rate the normal and carcinoma in situ tissues and with 89% accuracy the invasive SCC tissues of the tongue. Copyright © 2011 John Wiley & Sons, Ltd.
Influence of the chloro substituent position on the triplet reactivity of benzophenone derivatives: a time‐resolved resonance Raman and density functional theory study
Authors: Li Wen , Xue Jiadan , Cheng Shun Cheung , Du Yong , Phillips David Lee
Published: October 2011

A nanosecond time‐resolved resonance Raman (ns‐TR3) spectroscopic investigation of the photoreduction reactions and ability of several chloro‐substituted benzophenone (Cl‐BP) triplets is described. The TR3 results show that the 3‐chlorobenzophenone (3‐Cl‐BP), 4‐chlorobenzophenone (4‐Cl‐BP) and 4,4′‐dichlorobenzophenone (4,4′‐dichloro‐BP) triplets exhibit similar hydrogen abstraction ability with the parent BP triplet. In 2‐propanol, the 3‐Cl‐, 4‐Cl‐ and 4,4′‐dichloro‐diphenylketyl (DPK) radicals were observed and they appear to react with dimethylketyl radicals at the para‐position to form a light absorption transient species. These transient species were characterized with TR3 spectra, and identified with the help of results from density functional theory calculations. In an acetontitrile/water (MeCN:H2O) 1:1 mixed solvent, these DPK radicals were also observed but with slower formation rates. However, the 2‐Cl‐DPK radical was observed to form with a lower yield and a significantly slower formation rate than the other chloro‐substituted benzophenones examined here in 2‐propanol under the same experimental conditions. These results reveal that the 2‐chloro substituent reduces the hydrogen abstraction ability of the substituted BP triplet, which was not as expected based on the assumption that the electron‐withdrawing group could increase its photoreduction ability. This unusual ortho effect of the chlorine substitution is briefly discussed. Copyright © 2011 John Wiley & Sons, Ltd.
Commentary on the Separate Prologues by Humberto Maturana and Francisco Varela to the Second Edition of ‘De Máquinas y Seres Vivos—Autopoiesis: La organización de lo vivo’—Twenty Years After
Authors: Paucar‐Caceres Alberto , Harnden Roger
Published: October 2011

The present paper introduces two documents written separately by Humberto Maturana and Francisco Varela, which describe their early scientific and intellectual collaboration in the formulation of the idea of autopoiesis and reflect on how that idea impacted on the wider intellectual community up to the mid‐1990s. The paper invites consideration of these papers in the context of the history of science as a rich narrative as to the way in which social, personal and historical factors deeply impact on any such work. Copyright © 2011 John Wiley & Sons, Ltd.
My Encounters with Francisco Varela
Authors: Luisi Pier Luigi
Published: October 2011

I review here my personal and scientific interactions with Francisco Varela, starting from our meeting in 1983 in Alpbach, Austria, a momentous meeting, which was also the place where the Mind and Life Institute and independently the Cortona week were conceived. Later on, the scientific cooperation focussed on autopoiesis and permitted to arrive at the experimental autopoiesis on the basis of the self‐reproduction of micelles and vesicles. I then briefly describe how Francisco, based on the complementary notion of cognition, was able to draw the bridge between biology and cognitive sciences. The main keywords here are enaction and embodied mind. From here, and towards the end of his life, Francisco focussed mostly on neurobiology, where he introduced the notion of neurophenomenology centred on first‐person reports. However, his seminal work on autopoiesis was instrumental to conceive the new field of research on the minimal cells, which is briefly described. I conclude with an overview of the meaning of the work of Francisco for life sciences at large. Copyright © 2011 John Wiley & Sons, Ltd.
Immunohistochemical localization of enkephalin in the human striatum: A postmortem ultrastructural study
Authors: Mccollum Lesley A. , Roche Joy K. , Roberts Rosalinda C.
Published: October 2011

Within the basal ganglia, the functionally defined region referred to as the striatum contains a subset of GABAergic medium spiny neurons expressing the neuropeptide enkephalin. Although the major features of ultrastructural enkephalin localization in striatum have been characterized among various species, its ultrastructural organization has never been studied in the human brain. Human striatal tissue was obtained from the Maryland and Alabama Brain Collections from eight normal controls. The brains were received and fixed within 8 h of death allowing for excellent preservation suitable for electron microscopy. Tissue from the dorsal striatum was processed for enkephalin immunoreactivity and prepared for electron microscopy. General morphology of the dorsal striatum was consistent with light microscopy in human. The majority of neurons labeled with enkephalin was medium‐sized and had a large nonindented nucleus with a moderate amount of cytoplasm, characteristic of medium spiny neurons. Of the spines receiving synapses in dorsal striatum, 39% were labeled for enkephalin and were of varied morphologies. Small percentages (2%) of synapses were formed by labeled axon terminals. Most (82%) labeled terminals formed symmetric synapses. Enkephalin‐labeled terminals showed no preference toward spines or dendrites for postsynaptic targets, whereas in rat and monkey, the vast majority of synapses in the neuropil are formed with dendritic shafts. Thus, there is an increase in the prevalence of axospinous synapses formed by enkephalin‐labeled axon terminals in human compared with other species. Quantitative differences in synaptic features were also seen between the caudate nucleus and the putamen in the human tissue. Synapse, 2012. © 2011 Wiley Periodicals, Inc.
Dopaminergic modulation of nitric oxide synthase activity in subregions of the rat nucleus accumbens
Authors: Hoque Kristina E. , West Anthony R.
Published: October 2011

Nitric oxide (NO) is a gaseous neurotransmitter synthesized in the nucleus accumbens (NAc) by aspiny interneurons containing neuronal NO synthase (nNOS). nNOS activity is readily assayed using nicotinamide adenine dinucleotide phosphate‐diaphorase (NADPH‐d) staining and is believed to be regulated by activation of dopamine (DA) D1‐ and D2‐like receptors. However, the role of DA transmission in the regulation of nNOS activity in identified subregions of the NAc remains unexplored. In this study, the impact of pharmacological manipulations of D1, D2, and NMDA receptors on nNOS activity was determined using optical density measures of NADPH‐d staining preformed in multiple subdivisions (core, medial shell, intermediate shell, and lateral shell) of the NAc. Awake behaving rats received systemic administration of vehicle and/or the following drugs ∼25 min prior to tissue harvesting: the nNOS inhibitor NG‐propyl‐L‐arginine (NPA), the D1 receptor agonist SKF 81297, the D1 receptor antagonist SCH 23390, the D2 receptor agonist quinpirole (QNP), the D2 receptor antagonist eticlopride (ETI), or the NMDA receptor antagonist 3‐((±)2‐carboxypiperazin‐4‐yl)propyl‐1‐phosphonic acid (CPP). In vehicle‐treated animals, a distinct medial‐lateral histochemical gradient of NADPH‐d staining was observed, which was characterized by moderate staining in the core and medial shell and more robust staining in the intermediate and lateral shell. Administration of NPA, SCH 23390, QNP, and CPP attenuated staining preferentially in the intermediate and lateral shell. SKF 81297 and ETI administration consistently increased staining in the medial shell in a manner, which was attenuated following pretreatment with SCH 23390, QNP, NPA, and CPP. These observations demonstrate that nNOS activity measured in distinct subregions of the NAc is differentially modulated by DA D1 and D2 receptor activation. Moreover, these findings demonstrate for the first time that DA D1 and D2 receptor activation regulates the facilitatory influence of glutamatergic transmission on nNOS activity in the NAc medial shell via facilitation (D1) or suppression (D2) of NMDA receptor function. Synapse, 2012. © 2011 Wiley Periodicals, Inc.
Synthesis, Crystal Structure and Chemical Bonding of the Zintl Phase Rb7NaSi8
Authors: Goebel Thorsten , Prots Yurii , Ormeci Alim , Pecher Oliver , Haarmann Frank
Published: October 2011

Abstract. The Zintl phase Rb7NaSi8 was synthesized as single‐phase material. Powder and single‐crystal X‐ray diffraction, thermal analysis, chemical analysis, measurement of the magnetic susceptibility, and 23Na, 29Si, and 87Rb nuclear magnetic resonance (NMR) spectroscopy were employed to characterize the material. Rb7NaSi8 crystallizes in the Rb7NaGe8 type of structure forming trigonal pyramidal anions Si44–. Two unique environments of the cations are observed, the linear arrangement [Na(Si4)2]7– with short Na–Si distances of 2.94 Å and the Rb2 atom coordinated by six Si44– anions with long Rb–Si distances of 4.09 Å. The environment of the Rb1 atom is similar to the coordination of the rubidium atoms in Rb4Si4. The chemical bonding was investigated by quantum mechanical calculations of the electron localizability indicator (ELI), the electronic density of states (DOS), and NMR coupling parameters. Good agreement of theoretically calculated and experimentally determined NMR coupling parameters was obtained for both chemical shielding and quadrupole coupling. The anisotropy of chemical shielding (CSA) indicates an anisotropic bonding situation of the silicon atoms. This is confirmed by the observation of a lone‐pair‐like feature and three two‐center Si–Si bonds for each silicon atom using the ELI. The electric field gradients (EFG) of 23Na and 87Rb indicate the anisotropy of the charge distribution of the cations. In particular, the linear arrangement [Na(Si4)2]7– and the Rb1 atom feature anisotropic charge distributions of the cations. This is confirmed by calculating the anisotropy ratio defined as Δnp = n(pz)/(½[n(px)+n(py)]) with n(pi) corresponding to the integrated DOS of the respective state. The long distances of Rb2 to the six coordinating Si44– ions are reflected by the small EFG.
Composition Analysis of Free Fatty Acids from Swertia Species by a Novel Pre‐column Fluorescence Labelling Method Using HPLC‐FLD
Authors: Li Guoliang , Song Cuihua , You Jinmao , Zhang Xiaolong , Chen Guang
Published: October 2011

Free fatty acids (FFA) are basic and indispensable components of medicinal plants. Many researches indicate that the efficacy of medicinal plant requires the presence of FFA. In the present study, ultrasonic‐assisted extraction of FFA from Swertia species was optimized by response surface methodology (RSM), ensuring the highest FFA recoveries. A novel pre‐column fluorescence labelling method using 2‐(5‐benzoacridine)ethyl‐p‐toluenesulfonate (BAETS) as a labelling reagent has been developed for highly sensitive and selective analysis of FFA by HPLC with fluorescent detection (FLD) and online mass spectrometry identification. RSM was also employed to optimize the fluorescence labelling of FFA. HPLC separation of 17 FFA derivatives was carried out on a reversed‐phase Hypersil BDS C8 column (4.6 × 200 mm, 5 μm, Agilent Co.) with a gradient elution. The detection limits and quantifications were as low as 0.60 and 1.22 ng mL−1, respectively. FFA analysis from nine Swertia species was performed by the newly developed method, and the FFA composition of these Swertia samples was first reported.
Non-termination and secure information flow
Authors: SMITH GEOFFREY , ALPÍZAR RAFAEL
Published: October 2011

In secure information flow analysis, the classic Denning restrictions allow a program's termination to be affected by the values of itsHvariables, resulting in potential information leaks. In an effort to quantify such leaks, in this paper we study a simple imperative language with random assignments. As a thought experiment, we propose a ‘stripping’ operation on programs, which eliminates all ‘high computation’, and prove the fundamental property that stripping cannot decrease the probability of any low outcome. To prove this property, we first introduce a new notion offast probabilistic simulationon Markov chains and show that it implies a key reachability property. Viewing the stripping function as a binary relation, we then prove that stripping is a fast simulation. As an application, we prove that, under the Denning restrictions, well-typed probabilistic programs are guaranteed to satisfy an approximate probabilistic non-interference property, provided that their probability of non-termination is small.
Decision-Support Tool in Prehospital Care: A Systematic Review of Randomized Trials
Authors: Hagiwara Magnus , Henricson Maria , Jonsson Anders , Suserud Björn-Ove
Published: October 2011

Objective: The objective of this study was to evaluate the effects of the decision support tool (DST) on the assessment of the acutely ill or injured out-of-hospital patient.

Methods: This study included systematic reviews of randomized controlled trials (RCT) where the DST was compared to usual care in and out of the hospital setting. The databases scanned include: (1)Cochrane Reviews(up to January 2010); (2)Cochrane Controlled Clinical Trials(1979 to January 2010); (3)Cinahl(1986 to January 2010); and (4)Pubmed/Medline(1926 to January 2010). In addition, information was gathered from related magazines, prehospital home pages, databases for theses, conferences, grey literature and ongoing trials.

Results: Use of the DST in prehospital care may have the possibility to decrease “time to definitive care” and improve diagnostic accuracy among prehospital personnel, but more studies are needed.

Conclusions: The amount of data in this review is too small to be able to draw any reliable conclusions about the impact of the use of the DST on prehospital care. The research in this review indicates that there are very few RCTs that evaluate the use of the DST in prehospital care.
Our Indian Railway
Authors: Srinivasan Roopa , Tiwari Manish , Silas Sandeep
Published: October 2011

This book commemorates 150 years of railways in India. Introduced under colonial rule in the second half of the nineteenth century, the railways soon embraced the length and breadth of India bringing with it rapid political, economic, ecological and cultural changes. The articles in this book explore the impact of this technological phenomenon from a range of interdisciplinary perspectives. From early railway thinking in renaissance Bengal, to railway policing in Uttar Pradesh and issues of management to railway themes in literature, the writers in this volume reveal the world of the railways in all its exciting facets. The photo essay invokes the nostalgic world of steam with a series of evocative images. In the twenty-first century, the ever expanding horizon of the railways continues to draw in people and goods in the third largest railway network in the world.
Himalayan Degradation
Authors: Datt Dangwal Dhirendra
Published: October 2011

Himalayan Degradation, Colonial Forestry and Environmental Change in India questions the recent trend of treating environmental and agrarian concerns as two separate domains. In this aspect, the book goes beyond the existing framework of environmental history that focuses only on the study of state policies and debates over redefining rights and examining protests. The author makes a careful study of the larger rural economy, emphasising the changing significance of pastoralism, trade and foraging in the life of the common people. He links forest degradation and environmental change to socioeconomic transformation.Underlining the centrality of forests and mountain resources to the livelihood and culture of the people of Uttarakhand, the book subjects the notion of sustainable management of forests to close scrutiny.
Politics, Society and Colonialism
Authors: Mukhopadhyay Amartya
Published: October 2011

Even as his 150th birth anniversary draws near, Rabindranath Tagore remains quite under-explored. Nirad C. Chaudhuri predicted that the difficulty in translating Tagores work would ascertain that in future his work will lie like a buried city in the past. The difficulty of translating him in any of the European or modern Indian languages and his position as a cult figure in India contributed to this gap between adulation and understanding. Recent revival of interest in the West in Tagores work only partly redresses this imbalance. For, much of Tagores central claim to greatness lies in his social thought.
Organic Farming
Authors: Veeresh G. K. , Veeresh G.K.
Published: October 2011

Green Revolution Technologies have made India self-sufficient in food production but unable to sustain soil productivity. A quantum leap in production of over 100 million tones was achieved in just two decades (1960-1970). But during the 1980s and 1990s it was a struggle to add on another 10 million tonnes despite good monsoons and the increasing supply of inputs of fertilizers, high yielding seeds, pesticides as well as water through irrigation. High costs of inputs have turned farming into a loss-making enterprise while leading to severe environmental degradation.
Human Rights and Law
Authors: Tiwari Ramesh Kumar
Published: October 2011

Human Rights and Law: Bonded Labour in India deals with the problem of debt bondage and the way it has been treated during the British as well as in the post-independence period. Analysis has been made of the motivations for carrying out the reform; the processes involved in formulating the legislation, contributions by different agencies, discussion in the parliament, etc. The two legislations: the Indian Slavery Act, 1843 and bonded labour system (Abolition) Act, 1976 provide a comparative perspective in the making of social legislation in two different historical settings and different political systems.
Multidecadal variability and late medieval cooling of near‐coastal sea surface temperatures in the eastern tropical North Atlantic
Authors: Kuhnert Henning , Mulitza Stefan
Published: October 2011

Multidecadal variations in Atlantic sea surface temperatures (SST) influence the climate of the Northern Hemisphere. However, prior to the instrumental time period, information on multidecadal climate variability becomes limited, and there is a particular scarcity of sufficiently resolved SST reconstructions. Here we present an eastern tropical North Atlantic reconstruction of SSTs based on foraminiferal Mg/Ca ratios that resolves multidecadal variability over the past 1700 years. Spectral power in the multidecadal band (50 to 70 years period) is significant over several time intervals suggesting that the Atlantic Multidecadal Oscillation (AMO) has been influencing local SST. Since our data exhibit high scatter the absence of multidecadal variability in the remaining record does not exclude the possibility that SST variations on this time scale might have been present without being detected in our data. Cooling by ∼0.5°C takes place between about AD 1250 and AD 1500; while this corresponds to the inception of the Little Ice Age (LIA), the end of the LIA is not reflected in our record and SST remains relatively low. This transition to cooler SSTs parallels the previously reconstructed shift in the North Atlantic Oscillation toward a low pre‐20th century mean state and possibly reflects common solar forcing.
Variability of total electron content over an equatorial West African station during low solar activity
Authors: Bolaji O. S. , Adeniyi J. O. , Radicella S. M. , Doherty P. H.
Published: October 2011

Slant total electron content (STEC) data measured by the Global Positioning System receiver at Ilorin, Nigeria, with geographical coordinates 8.47°N, 4.68°E for the year 2009 (a low‐activity year) was used to study the diurnal, monthly standard deviation and monthly median value of total electron content (TEC). The vertical total electron content (VTEC) values are estimated from the STEC data. The thin shell approximation with an ionospheric shell height of 350 km was used for the analysis. The diurnal variation of VTEC (DTEC) and its corresponding monthly median variation (MTEC) shows a minimum at presunrise between the hours of 05:00 and 06:00 LT. The DTEC values show a maximum variation range from ∼24 to ∼34 total electron content unit (TECU). The daytime maximum TEC values observed in all the months were broad with a slight daytime depression in May, June, July, and November. The maximum variation of MTEC after slight daytime depression is greater than its variation before the slight daytime depression in the months affected with the month of July as exception. The slight daytime depression was lowest in the month of May and has a value of 0.99 TECU. A postsunset decrease at 20:00 LT with corresponding enhancement 2 h later was observed in the month of March. This post sunset decrease and enhancement in the month of March could be a strong indicator of the abrupt onset of scintillations, plasma bubbles, and spread F phenomenon. The monthly standard deviation depicts summary behavior of all the diurnal variations in each month. Annual and seasonal variations were also investigated.
In glucose-limited continuous culture the minimum substrate concentration for growth, smin, is crucial in the competition between the enterobacterium Escherichia coli and Chelatobacter heintzii, an environmentally abundant bacterium
Authors: Füchslin Hans Peter , Schneider Christian , Egli Thomas
Published: October 2011

The competition for glucose between Escherichia coli ML30, a typical copiotrophic enterobacterium and Chelatobacter heintzii ATCC29600, an environmentally successful strain, was studied in a carbon-limited culture at low dilution rates. First, as a base for modelling, the kinetic parameters μmax and Ks were determined for growth with glucose. For both strains, μmax was determined in batch culture after different precultivation conditions. In the case of C. heintzii, μmax was virtually independent of precultivation conditions. When inoculated into a glucose-excess batch culture medium from a glucose-limited chemostat run at a dilution rate of 0.075 h−1C. heintzii grew immediately with a μmax of 0.17±0.03 h−1. After five transfers in batch culture, μmax had increased only slightly to 0.18±0.03 h−1. A different pattern was observed in the case of E. coli. Inoculated from a glucose-limited chemostat at D=0.075 h−1 into glucose-excess batch medium E. coli grew only after an acceleration phase of ∼3.5 h with a μmax of 0.52 h−1. After 120 generations and several transfers into fresh medium, μmax had increased to 0.80±0.03 h−1. For long-term adapted chemostat-cultivated cells, a Ks for glucose of 15 μg l−1 for C. heintzii, and of 35 μg l−1 for E. coli, respectively, was determined in 14C-labelled glucose uptake experiments. In competition experiments, the population dynamics of the mixed culture was determined using specific surface antibodies against C. heintzii and a specific 16S rRNA probe for E. coli. C. heintzii outcompeted E. coli in glucose-limited continuous culture at the low dilution rates of 0.05 and 0.075 h−1. Using the determined pure culture parameter values for Ks and μmax, it was only possible to simulate the population dynamics during competition with an extended form of the Monod model, which includes a finite substrate concentration at zero growth rate (smin). The values estimated for smin were dependent on growth rate; at D=0.05 h−1, it was 12.6 and 0 μg l−1 for E. coli and C. heintzii, respectively. To fit the data at D=0.075 h−1, smin for E. coli had to be raised to 34.9 μg l−1 whereas smin for C. heintzii remained zero. The results of the mathematical simulation suggest that it is not so much the higher Ks value, which is responsible for the unsuccessful competition of E. coli at low residual glucose concentration, but rather the existence of a significant smin.
Elastic incoherent neutron scattering operating by varying instrumental energy resolution: Principle, simulations, and experiments of the resolution elastic neutron scattering (RENS)
Authors: Magazù Salvatore , Migliardo Federica , Benedetto Antonio
Published: October 2011

The main aim of this paper is to present the scientific case of the resolution elastic neutron scattering (RENS) method that is based on the collection of elastic neutron scattering intensity as a function of the instrumental energy resolution and that is able to extract information on the system dynamical properties from an elastic signal. In this framework, it is shown that in the measured elastic scattering law, as a function of the instrumental energy resolution, an inflection point occurs when the instrumental energy resolution intersects the system relaxation time, and in an equivalent way, a transition in the temperature behavior of the measured elastic scattering law occurs when the characteristic system relaxation time crosses the instrumental energy resolution time. With regard to the latter, an operative protocol to determine the system characteristic time by different elastic incoherent neutron scattering (EINS) thermal scans at different instrumental energy resolutions is also proposed. The proposed method, hence, is not primarily addressed to collect the measured elastic scattering intensity with a great accuracy, but rather relies on determining an inflection point in the measured elastic scattering law versus instrumental energy resolution. The RENS method is tested both numerically and experimentally. As far as numerical simulations are concerned, a simple model system for which the temperature behavior of the relaxation time follows an Arrhenius law, while its scattering law follows a Gaussian behavior, is considered. It is shown that the system relaxation time used as an input for the simulations coincides with the one obtained by the RENS approach. Regarding the experimental findings, due to the fact that a neutron scattering spectrometer working following the RENS method has not been constructed yet, different EINS experiments with different instrumental energy resolutions were carried out on a complex model system, i.e., dry and D2O hydrated lysozyme, in an extended temperature range. The resulting temperature behavior of the system relaxation time, obtained with RENS method, agrees very well with the one obtained in literature, for the same system, following the quasi-elastic neutron scattering (QENS) approach. The proposed scientific case puts into evidence the challenges of an RENS spectrometer working by varying the instrumental energy resolution; in particular, in comparison with QENS, the proposed RENS method requires a smaller amount of sample, which is an important point in dealing with biological and exotic systems; it is not affected by the use of model functions for fitting spectra as in QENS, but furnishes a direct access to relevant information.
Pound-locking for characterization of superconducting microresonators
Authors: Lindström T. , Burnett J. , Oxborrow M. , Tzalenchuk A Ya.
Published: October 2011

We present a new application and implementation of the Pound-locking technique for the interrogation of superconducting microresonators. We discuss how by comparing against stable frequency sources this technique can be used to characterize properties of resonators that cannot be accessed using traditional methods. Specifically, by analyzing the noise spectra and the Allan deviation, we obtain valuable information about the nature of the noise in superconducting planar resonators. This technique also greatly improves the read-out accuracy and measurement throughput compared to conventional methods
Phonons with orbital angular momentum
Authors: Ayub M. K. , Ali S. , Mendonca J. T.
Published: October 2011

Ion accoustic waves or phonon modes are studied with orbital angular momentum (OAM) in an unmagnetized collissionless uniform plasma, whose constituents are the Boltzmann electrons and inertial ions. For this purpose, we have employed the fluid equations to obtain a paraxial equation in terms of ion density perturbations and discussed its Gaussian beam and Laguerre-Gauss (LG) beam solutions. Furthermore, an approximate solution for the electrostatic potential problem is presented, allowing to express the components of the electric field in terms of LG potential perturbations. The energy flux due to phonons is also calculated and the corresponding OAM is derived. Numerically, it is shown that the parameters such as azimuthal angle, radial and angular mode numbers, and beam waist, strongly modify the profiles of the phonon LG potential. The present results should be helpful in understanding the phonon mode excitations produced by Brillouin backscattering of laser beams in a uniform plasma.
Spin-orbit coupling effect on bismuth donor lasing in stressed silicon
Authors: Zhukavin R. Kh. , Kovalevsky K. A. , Tsyplenkov V. V. , Shastin V. N. , Pavlov S. G. , Hübers H.-W. , Riemann H. , Abrosimov N. V. , Ramdas A. K.
Published: October 2011

We report a study on terahertz lasing from optically excited Bi donors in axially compressed silicon crystal. The laser frequency and the radiated power were measured versus stress applied along the [100] crystal axis. As shown, Bi donors lase at the optical transitions from the 2p± states to the 1s (E) state or/and to the spin-orbit split 1s (T2:Γ8) and 1s (T2:Γ7) states, and by fitting the crystal strain, one can shift the laser transitions and change the output power. The experiment is explained by the dependence of spin-orbit splitting and phonon-assisted relaxation of donor states on crystal distortion.
Magnetic and spontaneous Barkhausen noise techniques used in investigation of a martensitic transformation
Authors: Capò Sànchez J. , Huallpa E. , Farina P. , Padovese L. R. , Goldenstein H.
Published: October 2011

Magnetic Barkhausen noise (MBN) was used to characterize the progress of austenite to martensite phase transformation while cooling steel specimens, using a conventional Barkhausen noise emission setup stimulated by an alternating magnetic field. The phase transformation was also followed by electrical resistivity measurements and by optical and scanning electron microscopy. MBN measurements on a AISI D2 tool steel austenitized at 1473 K and cooled to liquid nitrogen temperature presented a clear change near 225 K during cooling, corresponding to the MS (martensite start) temperature, as confirmed by resistivity measurements. Analysis of the resulting signals suggested a novel experimental technique that measures spontaneous magnetic emission during transformation, in the absence of any external field. Spontaneous magnetic noise emission measurements were registered in situ while cooling an initially austenitic sample in liquid nitrogen, showing that local microstructural changes, corresponding to an avalanche or “burst” phenomena, could be detected. This spontaneous magnetic emission (SME) can thus be considered a new experimental tool for the study of martensite transformations in ferrous alloys, at the same level as acoustic emission.
Metal-insulator transition at a depleted LaAlO3/SrTiO3 interface: Evidence for charge transfer induced by SrTiO3 phase transitions
Authors: Lü W. M. , Wang X. , Liu Z. Q. , Dhar S. , Annadi A. , Gopinadhan K. , Roy Barman A. , Su H. B. , Venkatesan T. , Ariando
Published: October 2011

Two anomalous bias dependent resistive peaks induced by the SrTiO3 structural phase transitions at 55 and 110 K were observed in a LaAlO3/SrTiO3 and Nb:SrTiO3 rectifying junction when the LaAlO3/SrTiO3 was depleted under reverse bias. At these transition temperatures, the barrier between LaAlO3/SrTiO3 and Nb:SrTiO3 showed abrupt changes in the tunneling energy under forward bias. The peak at 110 K was an insulator-metal phase transition while the peak at 55 K was a metal-insulator one. We propose that the phase transitions of the SrTiO3 substrate influence the charge transfer to the LaAlO3/SrTiO3 layer, giving rise to these anomalous resistive peaks.
Metal-oxide complementary inverters with a vertical geometry fabricated on flexible substrates
Authors: Dindar A. , Kim J. B. , Fuentes-Hernandez C. , Kippelen B.
Published: October 2011

We report on the fabrication of p-channel thin film transistors (TFTs) and vertically stacked complementary inverters comprised of a p-channel copper oxide TFT on top of an n-channel indium gallium zinc oxide TFT fabricated on a flexible polyethersulfone substrate. The p- and n-channel TFTs showed saturation mobility values of 0.0022 and 1.58 cm2/Vs, respectively, yielding inverters with a gain of 120 V/V. This level of performance was achieved by reducing the copper oxide channel thickness, allowing oxygen diffusion into the copper oxide layer at medium processing temperature (150 °C).
A carbon nanotube immunosensor for Salmonella
Authors: Lerner Mitchell B. , Goldsmith Brett R. , McMillon Ronald , Dailey Jennifer , Pillai Shreekumar , Singh Shree R. , Johnson A. T. Charlie
Published: October 2011

Antibody-functionalized carbon nanotube devices have been suggested for use as bacterial detectors for monitoring of food purity in transit from the farm to the kitchen. Here we report progress towards that goal by demonstrating specific detection of Salmonella in complex nutrient broth solutions using nanotube transistors functionalized with covalently-bound anti-Salmonella antibodies. The small size of the active device region makes them compatible with integration in large-scale arrays. We find that the on-state current of the transistor is sensitive specifically to the Salmonella concentration and saturates at low concentration (<1000 cfu/ml). In contrast, the carrier mobility is affected comparably by Salmonella and other bacteria types, with no sign of saturation even at much larger concentrations (108 cfu/ml).
Activation mechanism of theβ2-adrenergic receptor
Authors: Dror Ron O. , Arlow Daniel H. , Maragakis Paul , Mildorf Thomas J. , Pan Albert C. , Xu Huafeng , Borhani David W. , Shaw David E.
Published: October 2011

A third of marketed drugs act by binding to a G-protein-coupled receptor (GPCR) and either triggering or preventing receptor activation. Although recent crystal structures have provided snapshots of both active and inactive functional states of GPCRs, these structures do not reveal the mechanism by which GPCRs transition between these states. Here we propose an activation mechanism for theβ2-adrenergic receptor, a prototypical GPCR, based on atomic-level simulations in which an agonist-bound receptor transitions spontaneously from the active to the inactive crystallographically observed conformation. A loosely coupled allosteric network, comprising three regions that can each switch individually between multiple distinct conformations, links small perturbations at the extracellular drug-binding site to large conformational changes at the intracellular G-protein-binding site. Our simulations also exhibit an intermediate that may represent a receptor conformation to which a G protein binds during activation, and suggest that the first structural changes during receptor activation often take place on the intracellular side of the receptor, far from the drug-binding site. By capturing this fundamental signaling process in atomic detail, our results may provide a foundation for the design of drugs that control receptor signaling more precisely by stabilizing specific receptor conformations.
The SUMO-specific isopeptidase SENP2 associates dynamically with nuclear pore complexes through interactions with karyopherins and the Nup107-160 nucleoporin subcomplex
Authors: Goeres Jacqueline , Chan Pak-Kei , Mukhopadhyay Debaditya , Zhang Hong , Raught Brian , Matunis Michael J.
Published: October 2011

The association of small, ubiquitin-related modifier–specific isopeptidases (also known as sentrin-specific proteases, or SENPs) with nuclear pore complexes (NPCs) is conserved in eukaryotic organisms ranging from yeast to mammals. However, the functional significance of this association remains poorly understood, particularly in mammalian cells. In this study, we have characterized the molecular basis for interactions between SENP2 and NPCs in human cells. Using fluorescence recovery after photobleaching, we demonstrate that SENP2, although concentrated at the nuclear basket, is dynamically associated with NPCs. This association is mediated by multiple targeting elements within the N-terminus of SENP2 that function cooperatively to mediate NPC localization. One of these elements consists of a high-affinity nuclear localization signal that mediates indirect tethering to FG-repeat–containing nucleoporins through karyopherins. A second element mediates interactions with the Nup107-160 nucleoporin subcomplex. A third element consists of a nuclear export signal. Collectively, our findings reveal that SENP2 is tethered to NPCs through a complex interplay of interactions with nuclear import and export receptors and nucleoporins. Disruption of these interactions enhances SENP2 substrate accessibility, suggesting an important regulatory node in the SUMO pathway.