bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemical vapour etching of silicon and porous silicon: silicon solar cells and micromachining applications
Authors: Ben Jaballah A. , Hassen M. , Hajji M. , Saadoun M. , Bessais B. , Ezzaouia H.
Published: June 2005

In this work, we used HNO3/HF Vapour Etching (VE) of silicon (Si) wafers for the formation of different porous structures. Depending on the volume ratio of the HNO3/HF acid mixture, we can obtain Porous Silicon (PS) layers or a (NH4)2SiF6 like powder phase. These two kind of porous structures may be used in silicon solar cells and in micromachining applications. The VE technique allows producing thick porous layers (>100 µm) in short times. Simple masking films enable to selectively groove Si wafers, leading to the formation of holes and channels of different sizes suitable for their application in micromachining. The various grooving profiles were investigated by Scanning electron microscopy (SEM). (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Porous GaAs as a possible antireflective coating and optical diffusor for III–V solar cells
Authors: Flamand Giovanni , Poortmans Jef
Published: June 2005

We have studied the possibility of using (nano‐)porous GaAs top layers as antireflective coating and optical diffusor in high‐efficiency III‐V solar cells. Antireflective coating behaviour of thin, nanoporous GaAs layers has been demonstrated, whereas initial experiments on applying these porous layers on top of a GaAs solar cell structure also suggest an optical diffusion of the incident light in the porous layer. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Painting a rainbow on silicon – a simple method to generate a porous silicon band filter gradient
Authors: Li Yang Yang , Kim Peter , Sailor Michael J.
Published: June 2005

A band filter gradient structure was obtained in porous Si by electrochemically etching a rugate structure into a Si wafer using an asymmetrically placed counter electrode. The resulting porous Si film displays a rejection band whose wavelength maximum varies spatially due to the uneven distribution of current across the wafer during the etch. The rainbow‐like band filter can be converted to a porous SiO2 graded band filter by thermal oxidization. A robust and flexible composite silicone/porous silicon gradient structure is achieved by impregnation with a silicone polymer. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A low‐power sensor for volatile organic compounds based on porous silicon photonic crystals
Authors: Dorvee Jason , Sailor Michael J.
Published: June 2005

A miniaturized, low‐power chemical sensor for volatile organic compounds using a porous Si photonic crystal is demonstrated. The device uses simple electronic circuitry a light‐emitting diode, a phototransistor, and thin film of a 1‐dimensional photonic crystal of porous Si, drawing 0.5 W of power. Integration of the freestanding porous silicon film with the conventional circuitry is discussed as well as the current detection limits for ethanol vapor in air. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fabrication of porous membrane filter from p‐type silicon
Authors: Grigoras K. , Franssila S. , Sikanen T. , Kotiaho T. , Kostiainen R.
Published: June 2005

Macropore formation and applications of low‐doped p‐type silicon have been studied. Traditional hydrofluoric acid/ethanol/water electrolyte and organic electrolytes containing dimethyl sulfoxide and hydrofluoric acid were used, and different anodization current densities were applied in order to optimize the pore formation and prevent cracking of the layer. Thin crystalline membranes were prepared by anisotropic wet etching from the backside, using a silicon nitride layer as a mask. A similar silicon nitride layer was used to define the area of the membrane to be porosified. Macroporous silicon membranes have been fabricated and tested as a filter for biomedical samples. Fluorescently labeled polystyrene beads, 1 µm in diameter, were succesfully used to demonstrate filter action. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High‐aspect‐ratio silicon dioxide pillars
Authors: Trifonov T. , Rodríguez A. , Servera F. , Marsal L. F. , Pallarès J. , Alcubilla R.
Published: June 2005

This paper presents a technique for fabricating high‐aspect‐ratio silicon dioxide pillars by electrochemical etching of n‐type silicon in hydrofluoric acid (HF) solutions. Basic process flow and etching conditions are described, which make it possible to obtain high‐aspect‐ratio pillar arrays with good uniformity. Pillar arrays of different dimensions (i.e. diameter and separation) and of different arrangements can be produced in a single etch step on the same wafer. The large surface area makes these pillar arrays possible candidates for applications in biological sensing. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photodetectors from Porous Silicon
Authors: Rossi A. M. , Bohn H. G.
Published: June 2005

A metal–semiconductor–metal photoconductive detector has been fabricated from porous silicon. To that aim low conductive p‐type Si (20 Ω cm) has been porosified and several rapid‐thermal treatment steps applied before deposition of Al‐contacts. The photo response was investigated in the wavelength range of 350–800 nm. A responsivity of up to 4 A/W was observed at 600 nm which is about 13 times higher than that of a commercial photodiode. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Laser local oxidation of porous silicon: a FTIR spectroscopy investigation
Authors: Rocchia M. , Rossi A. M. , Borini S. , Boarino L. , Amato G.
Published: June 2005

The local oxidation of porous silicon (PS), induced by a focused laser beam, could represent an alternative method for patterning PS through direct writing. Important phase changes take place on PS when irradiated by a focused laser beam and moreover a complete confinement of the oxidized areas can be achieved due to the very low thermal conductivity of PS. We present a detailed Fourier Transform InfraRed (FTIR) study of the irradiated areas to understand the degree of oxidation and the type of oxide obtained at different laser powers. An interpretation of the low wavenumber range, below 1300 cm–1, in terms of Fröhlich interactions will be discussed. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In situ observation of the evolution of porous silicon interference filter characteristics
Authors: Volk J. , Ferencz K. , Ramsden J. J. , Tóth A. L. , Bársony I.
Published: June 2005

Porous silicon multilayer formation was observed by in situ monitoring of the reflectivity spectra in the visible range. In order to reproduce the formation process optical model simulation was carried out. For demonstration of this method a 24‐layer microcavity structure was selected. Although in this low wavelengths region some absorption and scattering effects complicate the overall picture, the combined analysis throws new light upon the evolution of the porous silicon multilayer. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Light propagation and scattering in porous silicon nanocomposite waveguides
Authors: Pirasteh P. , Charrier J. , Dumeige Y. , Joubert P. , Haesaert S. , Chaillou A. , Haji L. , Le Rendu P. , Nguyen T. P.
Published: June 2005

Planar waveguides have been achieved from oxidised porous silicon layers (OPS) which have been impregnated by solvents, Congo Red (CR) dye and poly(p‐phenylene vinylene) (PPV) polymer. Optical loss has been investigated by a simple technique based on surface optical scattering measurements. Optical loss has been studied as a function of the wavelength, impregnation type and CR concentration. The main sources of attenuation, such as absorption, scattering from interface roughness, scattering from nano‐ crystallites and modification of the refractive indexes after filling are discussed. Optical loss measured at 0.633 µm is about 1.8 dB/cm for the OPS waveguides The optical loss decreases with wavelength. Otherwise, the optical loss increases with the concentration of Congo Red dye which is absorbent at this wavelength. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Excimer VUV formation of erbium‐doped silica layers
Authors: Yu J. J. , Boyd I. W.
Published: June 2005

Erbium‐doped silica sol–gel layers with post‐process excimer VUV irradiation at a low temperature of 400 °C have exhibited a strong room temperature Er luminescence at ∼1.53 µm. The VUV irradiation has led to the formation of Er oxides in the silica matrix while significantly reducing nonradiative decay channels associated with the OH groups in the sol–gel layers. High‐resolution transmission electron micros‐copy results revealed the formation of Er2O3 crystallites in the silica layers. The Er–O coordination and crystallisation altered the chemical environment of the Er ions in the silica while possibly reducing the quenching effect of the Er–Er cross‐relaxation, resulting in the strong Er luminescence emitted. Moreover, the low temperature VUV process would not produce the luminescence background offset which was found to be present in all the luminescence spectra of the silica layers processed thermally at 900 °C. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A simple inverse problem in solitonic chain deformations
Authors: Ferrer Rodrigo
Published: June 2005

We present a method that permits to obtain the nearest neighbor interaction potential starting from the shape of a spatial deformation of the chain of atoms. The deformations are considered to be traveling pulses. This potential does not necessarily have an analytical expression. Most of this work is focused on the usual formalism for solving Hamilton equations of motion. The concept of dual systems provides a highly efficient method to relate displacements from the equilibrium with generalized momenta and interaction potentials. We introduce generating functions from which sinusoidal waves and solitons are generated; then the corresponding interaction potentials are found. We arrive at the Hamiltonian and the energy of the system. A new kind of solitonic deformations is found for nonlinear chains which corresponds to an interaction potential similar to the Toda exponential potential but with a different dispersion relation to the speed of long‐wavelength sinusoidal waves. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Checklist for GCP compliance investigation (Medical institution)
Authors: Hirayama Kiyomi , Fukuda Naohisa , Satoh Hitoshi , Itoh Katsumi , Chiba Kiyoshi , Nakae Yutaka , Takezawa Masayuki , Gotoh Kuniko
Published: June 2005

This checklist is an English translation of the Good Clinical Practice (GCP) compliance checklist prepared by the Japanese agency for on‐site inspections of medical institutions. Please note that the checklist was translated by the authors and has not received official review by any Japanese agency including the Organization for Pharmaceutical Safety and Research (OPSR).

This checklist is an addendum to a previously published article on the evaluation of overseas GCP inspections by the Japanese Regulatory Agency [1]. Copyright © 2005 John Wiley & Sons, Ltd.
What's New?
Authors: Hattemer‐Apostel Rita , Broughton Harold Steven
Published: June 2005

The What's New? section in the Quality Assurance Journal aims to draw attention to items of importance to QA professionals. There is usually a three‐month interval between final submission of manuscripts and distribution of the journal. For this issue, the entries in the What's New? section arise from the period of 1 December 2004 to 28 February 2005. If you feel that there is any other new information that should be brought to the attention of readers, please let us know by e‐mailing rha@verdandi.ch. Copyright © 2005 John Wiley & Sons, Ltd.
An efficient, renormalized self‐energy for calculating the electron binding energies of closed‐shell molecules and anions
Authors: Ortiz J. V.
Published: June 2005

The energy‐dependent, nonlocal correlation potential known as the self‐energy that appears in the Dyson equation has a pole and residue structure that enables renormalizations of its low‐order, perturbative contributions to be estimated. The partial third‐order (P3) approximation has been extensively applied to the ionization energies of closed‐shell, organic molecules and is the most successful example of a low‐order, self‐energy method. A renormalization based on the P3 self‐energy estimates higher‐order contributions by scaling low‐order terms that chiefly describe final‐state relaxation. The resulting P3+ self‐energy retains the accuracy and efficiency of the P3 approximation, but also improves the latter method's performance with respect to the calculation of anion electron detachment energies without the introduction of adjustable parameters. An application to an anion that previously has yielded only to more intricate treatments of electron correlation demonstrates the power of this simple, new approximation. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
The Haemodynamic Status of Cardiac Surgical Patients in the Initial 2-h Recovery Period
Authors: Currey Judy , Botti Mari
Published: June 2005

Background: Critical care nurses caring for cardiac patients in the immediate postoperative period continually make decisions about the implications and treatment of their patients' haemodynamic status.

Aim: The aim of this study was to describe the haemodynamic status of patients on admission to critical care and over the 2-h period following cardiac surgery.

Methods: A quantitative, descriptive design was used. Data were collected using non-participant observation and an observation tool. The sample consisted of 38 patients.

Results: Analysis of data revealed the dynamic nature of the haemodynamic status of postoperative cardiac patients. On admission, 60% of patients ( n = 23) were haemodynamically unstable. The instability in these patients ( n = 23) was due to hypotension (34%), bleeding (21%) and hypoxaemia (18%). During the 2-h recovery period, 55% of patients were hypotensive, 16% of patients had low cardiac output syndrome and 16% of patients had low systemic vascular resistance (SVR) syndrome. Twenty-one percent of patients experienced bleeding complications. Shivering was a clinically significant problem in terms of occurrence (23%) and duration ( X = 45, S.D. = 30 min). Twenty-nine percent of patients ( n = 11) had a profound deterioration in haemodynamic status, necessitating urgent interventions.

Conclusion: Haemodynamic parameters indicate that 95% of patients in this study were haemodynamically unstable at some time during the initial 2-h recovery period. These findings inform resourcing decisions by organisations and have implications for nurses' assessment and interventional haemodynamic decision making.
Validation of Self Assessment Patient Knowledge Questionnaire for Heart Failure Patients
Authors: Lainscak Mitja , Keber Irena
Published: June 2005

Background: Several studies showed insufficient knowledge and poor compliance to non-pharmacological management in heart failure patients. Only a limited number of validated tools are available to assess their knowledge. The aim of the study was to test our 10-item Patient knowledge questionnaire.

Methods: The Patient knowledge questionnaire was administered to 42 heart failure patients from Heart failure clinic and to 40 heart failure patients receiving usual care. Construct validity (Pearson correlation coefficient), internal consistency (Cronbach α), reproducibility (Wilcoxon signed rank test), and reliability (chi-square test and Student's t-test for independent samples) were assessed.

Results: Overall score of the Patient knowledge questionnaire had the strongest correlation to the question about regular weighing ( r = 0.69) and the weakest to the question about presence of heart disease ( r = 0.33). There was a strong correlation between question about fluid retention and questions assessing regular weighing, ( r = 0.86), weight of one litre of water ( r = 0.86), and salt restriction ( r = 0.57). The Cronbach α was 0.74 and could be improved by exclusion of questions about clear explanation (Chronbach α 0.75), importance of fruit, soup, and vegetables (Chronbach α 0.75), and self adjustment of diuretic (Chronbach α 0.81). During reproducibility testing 91% to 98% of questions were answered equally. Patients from Heart failure clinic scored significantly better than patients receiving usual care (7.9 (1.3) vs. 5.7 (2.2), p < 0.001).

Conclusions: Patient knowledge questionnaire is a valid and reliable tool to measure knowledge of heart failure patients.
Characterization of ABC transporter ABCB1 expressed in human neural stem/progenitor cells
Authors: Islam Mohammed Omedul , Kanemura Yonehiro , Tajria Jesmin , Mori Hideki , Kobayashi Satoshi , Shofuda Tomoko , Miyake Jun , Hara Masayuki , Yamasaki Mami , Okano Hideyuki
Published: June 2005

We investigated the localization and functional expression of the ABC transporter ABCB1 in human fetal neural stem/progenitor cells (hNSPCs). RT‐PCR analysis revealed ABCB1 gene expression in hNSPCs. We found a single band in immunoblotted hNSPCs lysates probed with ABCB1 antibody, and detected ABCB1 at the hNSPCs cell membrane by immunocytochemistry and subcellular fractionation. ABCB1 inhibitors and substrate, and ATP‐depleting agents enhanced hNSPCs’ rhodamine 123 accumulation, and hNSPCs microsomes had vanadate‐sensitive ATPase activity. ABCB1 and nestin expression decreased during hNSPCs differentiation, while the astroglial marker GFAP increased. ABCB1 may maintain hNSPCs in an undifferentiated state and could be a neural stem/progenitor marker.
Testing the stability of the suitability coefficients from an eastern Bering Sea multispecies virtual population analysis
Authors: Jurado-Molina Jesús , Livingston Patricia A. , Gallucci Vincent F.
Published: June 2005

Suitability coefficients are important for the estimation of predation mortality in a multispecies virtual population analysis (MSVPA) and subsequent use in the multispecies forecasting model (MSFOR). Testing the assumption of the stability of the suitability coefficients is important in assessing the robustness of the predictions made with MSFOR. We used different statistical methods to partially test this assumption for the eastern Bering Sea MSVPA model with eight species, using stomach content data for the years 1985–1989. Comparison of the estimates from two different sets of stomach content data (set one with all data and set two mainly with data from 1985) suggested that the differences between the two types of estimates were much reduced when the number of predator stomachs sampled increased. In a second approach, we contrasted the residual variances of partial data sets with the results from the fit of the total data set. Results suggested a small increase (∼10.8%) in the variation of the suitability coefficients. Comparison of the means of the suitability coefficients associated with each predator species suggests that only 13 of the 50 possible pairwise contrasts were significantly different (α = 0.05). In general, results suggested that the predator preferences and prey vulnerabilities remained stable over the time period studied. Therefore, MSFOR could be considered as a tool to advise fisheries managers within a multispecies context.
Elbow Flexion Reconstruction by Steindler Flexorplasty in Obstetric Brachial Plexus Palsy
Authors: AL-QATTAN M. M.
Published: June 2005

The results of Steindler flexorplasty in nine patients with obstetric brachial plexus palsy are reported. There were 5 girls and 4 boys with a mean age of 6 (range 2–13) years. Selection criteria for the procedure included strong (at least M4) grip strength and wrist and elbow extension, as well as the presence of the “Steindler effect”. Pre-operatively, elbow flexion was rated as M0 or M1 in three patients and M2 in the remaining six patients. Intra-operatively, the detached common flexor origin was advanced 5 to 7 cm and fixation was done to the anterior humerus either with direct suture to the periosteum (in younger children) or suturing into a drill hole in the humerus (in older children). Postoperatively, the elbow was immobilized in flexion and supination for 6 weeks. At a mean follow-up of 5 years, the results in eight patients were good with mean active elbow flexion against resistance of 110° and a mean elbow flexion contracture of 35°. The result in the remaining patient was poor (unsuccessful transfer). It is concluded that the results of the Steindler flexorplasty in obstetric brachial plexus palsy patients are good and reliable, provided patient selection is careful.
The Management of Hand Injuries Caused by Sea Urchin Spines
Authors: NASSAB R. , RAYATT S. , PEART F.
Published: June 2005

Injuries to the hand by sea urchin spines are not commonly seen in the United Kingdom. There are many varieties of sea urchins (Echinoidea) throughout the world. They have a spherical calcium carbonate exoskeleton covered with spines. Certain varieties may be venomous, in particular the flower urchin ( Toxopneustes pileolus) found in the Indo-Pacific oceans. Injury may also be caused by the urchin spines or pedicellaria (delicate seizing organs equipped with jaws) ( Auerbach, 1991 ; Smith, 2002 ). A small number of hand injuries associated with sea urchin spines have been reported in the literature.
Four-Point Bending Strength of Transverse Osteotomies Stabilized with Various Kirschner Wire and Tension Wire Band Configurations
Authors: PEHLIVAN Ö. , KIRAL A. , MAHIROGULLARI M. , KOKSAL O. , KAPLAN H.
Published: June 2005

Four different fixation configurations of K-wires of two different diameters were used to stabilize a transverse osteotomy in chicken humerus bones. Four-point bending was applied to these to assess their apex dorsal bending rigidity. The configurations of K-wires included intramedullary, crossed and two with different tension wire band designs. One of these consisted of two transverse K-wires which did not cross the fracture line, around which the tension wire band was placed.

The results showed that there was no statistical significance between the two different tension band wiring techniques and that both were superior to the intramedullary and crossed K-wire fixation techniques.
Biomechanical Evaluation of a Four-Strand Modification of the Tang Method of Tendon Repair
Authors: CAO Y. , TANG J. B.
Published: June 2005

We report a four-strand modification of the Tang technique of tendon repair that uses fewer sutures and fewer knots on the tendon surface. This repair consists of four longitudinal and two horizontal strands that form a “U” configuration within the tendon made with a single looped suture. Thirty-four fresh pig flexor tendons were divided into 3 groups and repaired with the four-strand modified Tang method, a double-looped four-strand method or a double Kessler repair (four-strand). The tendons were subjected to a single cycle of load-to-failure test in a tensile testing machine. The initial force, 2-mm gap formation force and ultimate strength of the four-strand modified Tang repair were statistically identical to those of the double looped suture and were superior to those of the double Kessler repair. Ultimate strength was 43.4 ± 4.3 N for the four-strand modified Tang method, 45.2 ± 4.0 N for the double-looped method and 39.1 ± 4.0 N for the double Kessler repair. The four-strand modification of the Tang method appears to have strength sufficient for protected active finger motion. Given our preliminary clinical experience with this method, we recommend this new and simplified technique for clinical flexor tendon repairs.
The last hurrah: The 2004 Ukrainian presidential elections and the limits of machine politics
Authors: D’Anieri Paul
Published: June 2005

This paper considers Ukrainian politics from 1994 to 2004 (the term of Leonid Kuchma’s presidency) from the standpoint of ‘‘machine politics.’’ Many authors have argued that Ukraine and other post-Soviet states have combined elections with partly authoritarian regimes. The concept of machine politics, applied in this paper, helps explain how they do it. The paper then considers how and why the Kuchma machine collapsed in the ‘‘Orange Revolution’’ of 2004, and the comparative lessons of the Ukrainian experience.
Focusing on corruption: a reply to Ferraro and Katzner
Authors: Walpole Matthew J. , Smith Robert J.
Published: June 2005

Corruption is a complex phenomenon with various confounding effects and, in their separate replies, both Ferraro (2005) and Katzner (2005) note that in some cases corruption may have short- and long-term benefits for conservation by limiting extractive and destructive development activities. We agree, and we also acknowledge that better governance does not necessarily lead to better conservation; a cursory look at Conservation International's biodiversity hotspots (Conservation Interational, 2005) shows that these threatened regions occur in countries with both high and low governance levels.
Hunting bounties as a key measure of historical wildlife management and game conservation: Finnish bounty schemes 1647–1975
Authors: Pohja-Mykrä Mari , Vuorisalo Timo , Mykrä Sakari
Published: June 2005

In Finland, hunting bounties for pest animals were first introduced in the 1647 hunting law. Avian pests were included in bounty schemes a century later when a price was put on more than 20 species. The list of bounty species varied widely during the next 200 years. We examined the development of bounty schemes in Finnish wildlife management during 1647–1975 with respect to the prevailing attitudes to nature and hunting practices. We surveyed Finnish hunting legislation from the 1300s to the present, and collected hunting bounty data from hunting associations' archives and from statistics published in hunting magazines during the 19th and 20th centuries. Local municipalities and the government, and also hunters' and fishermen's organizations, paid bounties for pest species. Bounties were considered justified for direct and indirect economic, religious and ethical reasons. Organized persecution of pests was considered a necessary component of game management. The ‘golden age’ of bounty schemes from 1898 to the 1920s contributed to local extinctions of both mammalian and avian species. The cessation of law-based bounty schemes in 1975 was preceded by a period of strong environmental thinking, and bounty schemes were widely considered costly, outdated and unethical.
Assisted passage or passive drift: a comparison of alternative transport mechanisms for non-indigenous coastal species into the Southern Ocean
Authors: LEWIS PATRICK N. , RIDDLE MARTIN J. , SMITH STEPHEN D.A.
Published: June 2005

The introduction of invasive species may be the most profound modern threat to biological communities in high-latitude regions. In the Southern Ocean, the natural transport mechanism for shallow-water marine organisms provided by kelp rafts is being increasingly augmented by plastic debris and shipping activity. Plastic debris provide additional opportunities for dispersal of invasive organisms, but dispersal routes are passive, dependent on ocean currents, and already established. In contrast, ships create novel pathways, moving across currents and often visiting many locations over short periods of time. Transportation of hull-fouling communities by vessel traffic thus poses the most likely mechanism by which exotic species may be introduced to the Southern Ocean.
The first record of mycorrhizae on sub-Antarctic Heard Island: a preliminary examination
Authors: FRENOT Y. , BERGSTROM D.M. , GLOAGUEN J.C. , TAVENARD R. , STRULLU D.G.
Published: June 2005

Roots of nine of the 12 vascular plant species present on sub-Antarctic Heard Island were examined for mycorrhizae. All species examined had some type of mycorrhization with most possessing associations with vesicular-arbuscular mycorrhizae or dark septate mycorrhizae. The degree of mycorrhization varied considerably across sites. Sampled plants were growing on either morainic or beach substrates with some areas exposed only in the last century. As mycorrhizae are known to play an important role in the nutrient uptake by host-plants, these results support the idea that mycorrhizae can influence the capacities of plants to colonize in cold and low-nutrient environments such as sub-Antarctic glacier forelands. Comparisons with data from other sub-Antarctic islands are made.
Supraglacial moraines in Scharffenbergbotnen, Heimefrontfjella, Dronning Maud Land, Antarctica – significance for reconstructing former blue ice areas
Authors: HÄTTESTRAND CLAS , JOHANSEN NINA
Published: June 2005

The ice surface of the glacier in the 7 km long valley Scharffenbergbotnen in Heimefrontfjella, Dronning Maud Land, is characterized by blue ice fields and is partly covered by supraglacial moraine complexes. The debris cover of the supraglacial moraines is generally less than 50 cm thick and rests on glacial ice, and most of the surface morphology of ridges and numerous sink holes reflects irregularities in the underlying ice. The debris consists of angular to sub-angular clasts of local bedrock. We interpret the moraines to have an entirely supraglacial history, where colluvium and pre-existing moraines were brought into Scharffenbergbotnen primarily from the south/south-west by an advancing glacier during the last ice maximum in the region. The debris cover of the supraglacial moraines extends up to 200–250 m above the present ice surface on surrounding slopes in Scharffenbergbotnen, and generally to less than 100 m above the present ice surface on slopes outside the valley. We interpret this as marking the ice surface elevation in the area during the last ice maximum (probably LGM). The deposition of supraglacial moraines in the valley at that time, and their survival in the area until the present day, indicate that a local ablation centre and probably blue ice fields were present in Scharffenbergbotnen at LGM, and has been a persistent feature since. In a wider context, we argue that supraglacial moraines constitute a hitherto unexploited resource when reconstructing the former extent of blue ice areas.
Antarctic ice volume for the last 740 ka calculated with a simple ice sheet model
Authors: OERLEMANS J.
Published: June 2005

Fluctuations in the volume of the Antarctic ice sheet for the last 740 ka are calculated by forcing a simple ice sheet model with a sea-level history (from a composite deep sea δ18O record) and a temperature history (from the Dome C deuterium record). Antarctic ice volume reaches maximum values of about 30 × 1015 m3, 3 to 8 ka after glacial maxima [defined as maximum values of the deep sea δ18O record]. Minimum values of ice volume reached in the course of interglacial periods are about 26 × 1015 m3. Most of the time the temperature forcing (larger accumulation) and sea-level forcing (grounding-line retreat) tend to have competing effects. However, towards the end of a glacial cycle, when temperature rises and sea-level is still relatively low, the ice volume reaches a peak. The peak value is very sensitive to the relative phase of the sea-level forcing with respect to the temperature forcing. This is further studied by looking at the response of the model to purely periodic forcings with different relative phase. The large sensitivity of ice sheet size to the phase of the forcings may have some implications for dating of deep ice cores. Care has to be taken by using anchor points from the deep sea record.
Trace metals distributions in coastal sea ice of Terra Nova Bay, Ross Sea, Antarctica
Authors: GROTTI MARCO , SOGGIA FRANCESCO , IANNI CARMELA , FRACHE ROBERTO
Published: June 2005

In an attempt to clarify the release of trace elements from the seasonal coastal sea ice, samples were periodically collected in a nearshore station inside the Gerlache Inlet (Terra Nova Bay, Western Ross Sea), during the summer 2000/01 and analysed for dissolved and particulate cadmium, copper, iron, manganese and lead, as well as salinity, suspended particulate matter, nutrients and phytoplankton pigments. In order to provide insight on the metal association with the particles included in the sea ice, the metal solid speciation was also investigated. Both vertical distributions within the ice cores and temporal variations at the seawater interface were studied, in an effort to fully characterize the system and correlation among the considered parameters. Concentrations and speciation patterns clearly indicate metal incorporation within the annual sea ice due to resuspension of sediments, followed by release of particulate metals during melting as a primary process affecting trace metal availability in the Antarctic coastal waters.
The phosphoinositide 3-kinase pathway and cancer
Authors: Stokoe David
Published: June 2005

Human tumours emerge as the result of multiple genetic and epigenetic aberrations that allow the proto-cancer cell to escape normal social control. Many signal transduction pathways become constitutively active during this process, and one whose importance is increasingly being appreciated involves phosphoinositide 3-kinase (PI3-kinase). This pathway normally regulates important cell decisions such as growth, division, survival and migration, and when deregulated it can confer malignant potential to the ensuing tumour. However, constitutive activation of the PI3-kinase pathway might provide attractive therapeutic targets for the design of small-molecule inhibitors. This review discusses events upstream and downstream of PI3-kinase activity in the PI3-kinase signalling pathway, how PI3-kinase is deregulated in human tumourigenesis, and how this is being targeted clinically.
The Influence of Patient’s Interpersonal Schemas on Early Alliance Building
Authors: Beretta Véronique , de Roten Yves , Stigler Michael , Drapeau Martin , Fischer Mélanie , Despland Jean-Nicolas
Published: June 2005

Influence of patient’s interpersonal schemas on the establishment of the therapeutic alliance is examined on a sample of 60 outpatients during first dynamic psychotherapy sessions. To assess interpersonal characteristics, we used the Inventory of Interpersonal Problems (Horowitz et al., 1988) and the patient’s conflictual relationship themes (CCRT; Luborsky & Crits-Christoph, 1998). Alliance was measured with the Helping Alliance Questionnaire. The results show that therapeutic alliance is associated with patient’s wish to be close, to perceive others as being trustworthy and as helpful. Patients with low alliance more often express the wish to be close to others, but perceive others’ responses more negatively, as indicated by their representations of others as “hurtful and untrustworthy” and “unhelpful”. They also present more interpersonal problems linked to a diminished capacity for affiliation. Clinical implications of the results are discussed.
Relationship between Citizenship Behaviors and Tendencies to Withdraw among Nigerian Agribusiness Employees
Authors: Ladebo Olugbenga J.
Published: June 2005

This study examines the effects of diminished levels of citizenship behaviors and Type A behavioral pattern (TABP) on quit intentions and withdrawal behaviors of employees in diverse agricultural occupations. Participants were 191 post-graduate students at the University of Agriculture, in Southwestern Nigeria. Bivariate correlation shows that trait TABP is positively related to employee loyalty and participation. Hierarchical moderated multiple regression results indicate that trait TABP is unrelated to either quit intentions or withdrawal behaviors; loyalty behavior is inversely related to quit intentions and employee participation is negatively related to withdrawal behaviors. Trait TABP moderates the relationship between participation and withdrawal behaviors. The reluctance of an employee to exhibit loyalty and participatory behaviors may be an indication that s/he is willing to leave the job or engage in withdrawal behaviors.
Numerical sensitivity studies on the variability of climate‐relevant processes in the Barents Sea
Authors: Harms I. H. , Schrum C. , Hatten K.
Published: June 2005

The Barents Sea is a key region in the North Atlantic/Arctic Ocean climate system because of the intense ocean‐atmosphere heat exchange and the formation of sea ice. The latter process is connected with salt input, so‐called “brine release,” whereby water masses of Atlantic origin can be transformed into dense shelf bottom waters. To investigate the sensitivity of simulated, climate‐relevant processes to different but well‐established and realistic initial and boundary data, a high‐resolution coupled ice‐ocean model is applied to the Barents Sea. The model is based on the Hamburg Shelf Ocean Model and runs on a 7 × 7 km grid, based on the International Bathymetric Chart of the Arctic Ocean topography. The model is initialized with different temperature and salinity data from the Arctic Climate System Study BarKode data set and is forced with National Centers for Environmental Prediction atmospheric data. Eight sensitivity experiments with initial and boundary conditions in different combinations are performed over a period of 6 years (1979–1984). Results are analyzed with special emphasis on the ocean‐atmosphere heat exchange, the ice extent, and the brine release. The experimental variability is compared to the interannual climatic variability in order to assess the role of different forcing terms for regional climate modeling. Our results show that the experimental variability can be partly of the same order than the interannual variability, which suggests that data uncertainties could easily bias the results of climate variability studies. Modification of the Barents Sea inflow had the strongest effect on model results. The ocean‐atmosphere heat flux proved to be the most sensitive parameter to oceanic and atmospheric anomalies, whereas the ice extent and the corresponding salt input is more invariant to different boundary conditions.
Seasonal variations in oxygen isotope ratios of daily collected precipitation and wind drift samples and in the final snow cover at Dome Fuji Station, Antarctica
Authors: Motoyama Hideaki , Hirasawa Naohiko , Satow Kazuhide , Watanabe Okitsugu
Published: June 2005

Freshly fallen snow, drifting snow, and surface snow samples were collected between February 1997 and January 1998 at the Dome Fuji Station (77.19°S, 39.42°E, 3,810 meters above sea level (MASL)) located approximately 1000 km from the nearest coast. All the collected samples were analyzed for δ18O at the National Institute of Polar Research (NIPR) at Tokyo. The temperature at the top of the boundary layer (TBL) was measured at least twice a week. As expected, all collected samples show seasonal variations with higher values in summer and lower values in winter. However, the relationship with the surface air temperature (Ta) was found to be different for each species of samples. During the sampling year, the surface air temperature, which was measured using the classical methods, was found to be about 3°C higher than the mean surface temperature Ts, defined as the firn layer temperature at 10 m depth. One important process that leads to differences between the freshly deposited snow and the surface firn layer is the sublimation of air moisture during the winter months. Remarkable progress has recently been made to explain the δ2H and δ18O distribution patterns for Polar Regions with GCMs. Detailed observations at the Dome Fuji station reveal that δ18O values for the individual snowfalls are only partly explained by the improved Rayleigh type models, and that the processes after snow deposition also have to be taken into account.
Intercomparison of shortwave radiative transfer codes and measurements
Authors: Halthore Rangasayi N. , Crisp David , Schwartz Stephen E. , Anderson G. P. , Berk A. , Bonnel B. , Boucher O. , Chang Fu‐Lung , Chou Ming‐Dah , Clothiaux Eugene E. , Dubuisson P. , Fomin Boris , Fouquart Y. , Freidenreich S. , Gautier Catherine , Kato Seiji , Laszlo Istvan , Li Z. , Mather J. H. , Plana‐Fattori Artemio , Ramaswamy V. , Ricchiazzi P. , Shiren Y. , Trishchenko A. , Wiscombe W.
Published: June 2005

Computation of components of shortwave (SW) or solar irradiance in the surface‐atmospheric system forms the basis of intercomparison between 16 radiative transfer models of varying spectral resolution ranging from line‐by‐line models to broadband and general circulation models. In order of increasing complexity the components are: direct solar irradiance at the surface, diffuse irradiance at the surface, diffuse upward flux at the surface, and diffuse upward flux at the top of the atmosphere. These components allow computation of the atmospheric absorptance. Four cases are considered from pure molecular atmospheres to atmospheres with aerosols and atmosphere with a simple uniform cloud. The molecular and aerosol cases allow comparison of aerosol forcing calculation among models. A cloud‐free case with measured atmospheric and aerosol properties and measured shortwave radiation components provides an absolute basis for evaluating the models. For the aerosol‐free and cloud‐free dry atmospheres, models agree to within 1% (root mean square deviation as a percentage of mean) in broadband direct solar irradiance at surface; the agreement is relatively poor at 5% for a humid atmosphere. A comparison of atmospheric absorptance, computed from components of SW radiation, shows that agreement among models is understandably much worse at 3% and 10% for dry and humid atmospheres, respectively. Inclusion of aerosols generally makes the agreement among models worse than when no aerosols are present, with some exceptions. Modeled diffuse surface irradiance is higher than measurements for all models for the same model inputs. Inclusion of an optically thick low‐cloud in a tropical atmosphere, a stringent test for multiple scattering calculations, produces, in general, better agreement among models for a low solar zenith angle (SZA = 30°) than for a high SZA (75°). All models show about a 30% increase in broadband absorptance for 30° SZA relative to the clear‐sky case and almost no enhancement in absorptance for a higher SZA of 75°, possibly due to water vapor line saturation in the atmosphere above the cloud.
Development of land surface albedo parameterization based on Moderate Resolution Imaging Spectroradiometer (MODIS) data
Authors: Liang Xin‐Zhong , Xu Min , Gao Wei , Kunkel Kenneth , Slusser James , Dai Yongjiu , Min Qilong , Houser Paul R. , Rodell Matthew , Schaaf Crystal Barker , Gao Feng
Published: June 2005

A new dynamic‐statistical parameterization of snow‐free land surface albedo is developed using the Moderate Resolution Imaging Spectroradiometer (MODIS) products of broadband black‐sky and white‐sky reflectance and vegetation and the North American and Global Land Data Assimilation System (LDAS) outputs of soil moisture during 2000–2003. The dynamic component represents the predictable albedo dependences on solar zenith angle, surface soil moisture, fractional vegetation cover, leaf plus stem area index, and greenness, while the statistical part represents the correction for static effects that are specific to local surface characteristics. All parameters of the dynamic and statistical components are determined by solving nonlinear constrained optimization problems of a physically based conceptual model for the minimization of the bulk variances between simulations and observations. They all depend on direct beam or diffuse radiation and visible or near‐infrared band. The dynamic parameters are also functions of land cover category, while the statistical factors are specific to geographic location. The new parameterization realistically represents surface albedo variations, including the mean, shape, and distribution, around each dependent parameter. For composites of all temporal and spatial samples of the same land cover category over North America, correlation coefficients between the dynamic component of the new parameterization and the MODIS data range from 0.39 to 0.88, while relative errors vary within 8–42%. The gross (i.e., integrated over all categories) correlations and errors are 0.57–0.71 and 17–26%, changing with direct beam or diffuse radiation and visible or near‐infrared band. The static local correction results in a further reduction in relative errors, producing gross values of 11–21%. The new parameterization is a marked improvement over the existing albedo scheme of the state‐of‐the‐art Common Land Model (CLM), which has correlation coefficients from −0.57 to 0.71 and relative errors of 18–140% for individual land cover categories, and gross values of 0.03–0.32 and 37–71%, respectively.
Spatio‐temporal variability of lightning activity over the Indian region
Authors: Kandalgaonkar S. S. , Tinmaker M. I. R. , Kulkarni J. R. , Nath A. , Kulkarni M. K. , Trimbake H. K.
Published: June 2005

Spatio‐temporal variability of lightning activity over the Indian land mass region (8°N–33°N, 73°E–86°E) has been studied using monthly satellite based lightning flash grid (5° × 5°) data for 5‐year (1998–2002) period. These data have been examined for depicting the annual, seasonal, and spatial distribution of the lightning activity. The study revealed the nonlinear relationship between lightning flash density and latitude on the annual timescale, and it is linked with the convective activity, large‐scale circulations, land mass gradient, and orography of the region under study. On the seasonal timescale, the nonlinear positive relationships were observed in the premonsoon and monsoon seasons whereas a bimodal variation is observed in the post‐monsoon season. The comparison of flash density with maximum surface air temperature shows the existence of nonlinear relationship between the two parameters. The approximate range of increase of flash density per 1°C rise in temperature is 20 to 44%. The lightning flash density shows a pronounced semiannual oscillation over the latitude belts 8°N–28°N.
Using multiple beams to identify radio frequency interference in the search for extraterrestrial intelligence
Authors: Harp G. R.
Published: June 2005

The Allen Telescope Array (ATA) is a multiuser instrument and will perform simultaneous radio astronomy and radio search for extraterrestrial intelligence (SETI) observations. It is a multibeam instrument, with 16 independently steerable dual‐polarization beams at four different tunings. Here we describe a new method for identifying radio frequency interference (RFI) that leverages the unique attributes of the ATA. Given four beams at one tuning, it is possible to distinguish RFI from true ETI signals by pointing the beams in different directions. Any signal that appears in more than one beam can be identified as RFI and ignored. We discuss the effectiveness of this approach using realistic simulations of the fully populated 350 element configuration of the ATA as well as the interim 32 element configuration. Over a 5 min integration period, we find RFI rejection ratios exceeding 50 dB over most of the sky.
Radio frequency interference identification and mitigation using simultaneous dual‐station observations
Authors: Bhat N. D. R. , Cordes J. M. , Chatterjee S. , Lazio T. J. W.
Published: June 2005

Radio frequency interference (RFI) mitigation is a critically important issue in radio astronomy using existing instruments as well as in the development of next generation radio telescopes, such as the Square Kilometer Array (SKA). Most designs for the SKA involve multiple stations with spacings of up to a few thousands of kilometers and thus can exploit the drastically different RFI environments at different stations. As demonstrator observations and analysis for SKA‐like instruments, and to develop RFI mitigation schemes that will be useful in the near term, we recently conducted simultaneous observations with Arecibo Observatory and the Green Bank Telescope. The observations were aimed at diagnosing RFI and using the mostly uncorrelated RFI between the two sites to excise RFI from several generic kinds of measurements such as giant pulses from Crab‐like pulsars and weak H I emission from galaxies in bands heavily contaminated by RFI. This paper presents observations, analysis, and RFI identification and excision procedures that are effective for both time series and spectroscopy applications using multistation data.