bluuebunny/crossref_metadata_2025 huggingface dataset:
Doubling the one‐sided p‐value in testing independence in 2 × 2 tables against a two‐sided alternative
Authors: Lloyd Christopher J.
Published: April 2007

Dupont investigated the advantages of doubling the one‐sided P‐value in conducting a two‐sided test of independence in a 2 × 2 table and claimed that the main advantage was that, unlike the ‘exact’ P‐value, small changes in the table resulted in small changes in the significance. He admitted that this practice had no obvious theoretical justification. In this paper, I take the view that repeated sampling properties should form the basis of any such justification. I develop an appropriate framework for studying P‐values and show that doubling the one‐sided P‐value produces a biased test whenever the table is asymmetric. I show how one may derive a slightly more complicated P‐value from a uniformly most powerful test. While there are difficulties in interpreting these P‐values, I argue that, in principle, one should prefer the latter. In practice the difference between the two is typically less than 10 per cent (for the tables Dupont considered, the difference is of the order of 1 per cent) but with highly skew tables the difference can be much larger.
Adjusting for baseline: Change or percentage change?
Authors: Kaiser Lee
Published: April 2007

Clinical trials data often include baseline and response measurements on each patient. Comparisons of treatments commonly employ either change from baseline or percentage change from baseline as the analysis variable. This paper provides guidance on the choice between these two by means of plots of these variables versus baseline. I provide two examples that illustrate the problem and I discuss the impact of use of the wrong adjusted response.
A discussion on the conventional estimator of sensitivity and specificity in multiple tests
Authors: Lui Kung‐Jong
Published: April 2007

Both the variation of positive responses (negative responses) among individuals and the internal correlation among responses for the same individual affect the precision of the estimate of sensitivity (specificity). To estimate the sensitivity (specificity) of a medical diagnostic test, this paper proposes a Bayesian approach with a simple Markov model to evaluate the performance of the conventional estimator under different situations. On the basis of the assumed model, we derive a general formula for the variance of the conventional estimator regarding multiple tests and present a quantitative discussion on the limitations of this estimator.
Survival analysis in natural history studies of disease
Authors: Cnaan Avital , Ryan Louise
Published: April 2007

Clinicians often wish to use data from clinical trials or hospital databases to study disease natural history. Of particular interest are estimated survival and prognostic factors. In this context, it may be appropriate to measure survival from diagnosis or some other time origin, possibly prior to study entry. We describe the application of methods for truncated survival data, and compare these with the standard product limit estimator and proportional hazards models in the measurement of survival from entry. Theoretical considerations suggest that analysis of survival from entry may under‐ or overestimate the survival distribution of interest, depending on the shape of the true underlying hazard. Analogous results hold for the coefficients from a proportional hazards model. We illustrate our findings with data from a multicenter clinical trial and a hospital database.
On the statistical analysis of ROC curves
Authors: Thompson M. L. , Zucchini W.
Published: April 2007

We introduce a new accuracy index for receiver operating characteristic (ROC) curves, namely the partial area under the binormal ROC graph over any specified region of interest. We propose a simple but general procedure, based on a conventional analysis of variance, for comparing accuracy indices derived from two or more different modalities. The proposed method is related to and compared with existing methodology, and is illustrated by results from an experiment on optimization of density and contrast yielded by multiform photographic images used for scintigraphy.
Mixture models for partially unclassified data: A case study of renal venous renin in hypertension
Authors: McLachlan G. J. , Gordon R. D.
Published: April 2007

In many applications of discriminant analysis in medicine, data of known origin which can be reasonably assumed to be a random sample from the entire class may not be available for each of the possible classes. In this paper we note how such situations can be handled by using finite mixture models to formulate the estimation problem. This approach is adopted to model the distribution of the renal venous renin ratio (RVRR) between left and right kidneys in patients with hypertension. This distribution is used in the formation of a probabilistic allocation rule as an aid in the diagnosis of renal artery stenosis, which is potentially curable by surgery.
Changes in executive compensation following an environmental shift: the role of top management team turnover
Authors: Cho Theresa S. , Shen Wei
Published: April 2007

In this study we examine the changes in executive compensation at the top management team (TMT) level following an environmental shift. Using the context of deregulation in the airline industry, we find that: (1) a dramatic environmental change that heightens managerial discretion leads to greater pay level and performance sensitivity of TMT compensation; and (2) the greater the magnitude of turnover among TMT members following the environmental shift, the greater the compensation change. Copyright © 2007 John Wiley & Sons, Ltd.
Acquisitions of private vs. public firms: Private information, target selection, and acquirer returns
Authors: Capron Laurence , Shen Jung‐Chin
Published: April 2007

The acquisition of privately held firms is a prevalent phenomenon that has received little attention in mergers and acquisitions research. In this study, we examine three questions: (1) What drives the acquirer's choice between public and private targets? (2) Do acquisitions of private targets elicit a more positive stock market reaction than acquisitions of public targets, which, on average, destroy value for acquirers' shareholders? (3) Do acquirers gain when their selection of a public or private target fits the theory? In this paper, we argue that the lack of information on private targets limits the breadth of the acquirer's search and increases its risk of not evaluating properly the assets of private targets. At the same time, less information on private targets creates more value‐creating opportunities for exploiting private information, whereas the market of corporate control for public targets already serves as an information‐processing and asset valuation mechanism for all potential bidders. Using an event study and survey data, we find that: (1) acquirers favor private targets in familiar industries and turn to public targets to enter new business domains or industries with a high level of intangible assets; (2) acquirers of private targets perform better than acquirers of public targets on merger announcement, after controlling for endogeneity bias; (3) acquirers of private firms perform better than if they had acquired a public firm, and acquirers of public firms perform better than if they had acquired a private firm. These results support the expectation that acquirer returns from their target choice (private/public) are not universal but depend on the acquirer's type of search and on the merging firms' attributes. Copyright © 2007 John Wiley & Sons, Ltd.
Market orientation and performance
Authors: Connor Tom
Published: April 2007

This response is prompted by Hult, Ketchen and Slater's (2005) article entitled ‘Market orientation and performance: an integration of disparate approaches.’ As a contributor to the foregoing debate in the pages of this journal to which they refer I am writing to offer some observations on the nature and implications of the research reported in their paper and to clarify my essential difficulty as a strategist with the ‘market‐oriented: customer‐led’ construct. Copyright © 2007 John Wiley & Sons, Ltd.
XAS analysis on mesoporous vanadium oxide thin films by sol‐gel
Authors: Cremonesi A. , Calestani G. , Antonioli G. , Bersani D. , Lottici P. P. , Djaoued Y. , Brüning R.
Published: April 2007

In this work an extended x‐ray absorption fine structure (EXAFS) analysis on sol‐gel derived VOx thin films, templated using polyethylene glycol (PEG), is reported. The results, together with previous Raman and x‐ray diffraction (XRD) investigation, indicate two different structures for our samples: the first is characterized by a nearly 3D network with both axial and planar order, while the second has a 2D‐character with short range order. Copyright © 2007 John Wiley & Sons, Ltd.
Civilian Extraperitoneal Rectal Gunshot Wounds: Surgical Management Made Simpler
Authors: Navsaria Pradeep H. , Edu Sorin , Nicol Andrew J.
Published: April 2007

Background

Rectal injuries are associated with significant morbidity and mortality. Controversy persists regarding routine presacral drainage, distal rectal washout (DRW), and primary repair of extraperitoneal rectal injuries. This retrospective review was performed to determine the outcome of rectal injuries in an urban trauma center with a high incidence of penetrating trauma where a non‐aggressive surgical approach to these injuries is practiced.

Methods

The records of all patients with a full‐thickness penetrating rectal injury admitted to the Trauma Center at Groote Schuur Hospital over a 4‐year period were reviewed. These were reviewed for demographics, injury mechanism and perioperative management, anatomical site of the rectal injury, associated intra‐abdominal injuries and their management. Infectious complications and mortality were noted. Intraperitoneal rectal injuries were primarily repaired, with or without fecal diversion. Extraperitoneal rectal injuries were generally left untouched and a diverting colostomy was done. Presacral drainage and DRW were not routinely performed.

Results

Ninety‐two patients with 118 rectal injuries [intraperitoneal (7), extraperitoneal (59), combined (26)] were identified. Only two extraperitoneal rectal injuries were repaired. None had presacral drainage. Eighty‐six sigmoid loop colostomies were done. Two (2.2%) fistula, one rectocutaneous, and one rectovesical, were recorded. There were nine (9.9%) infectious complications: surgical site infection (4), buttock abscess (1), buttock necrosis (1), pubic ramus osteitis (1), septic arthritis (2). No perirectal sepsis occurred.

Conclusions

Extraperitoneal rectal injuries due to low‐velocity trauma can be safely managed by fecal diversion alone.
Reverse Radial Forearm Flap Peforator Used in Digital Revascularization
Authors: Lo Steven , Sebastin Sandeep , Tsai Larry , Pin Peng Yeong
Published: April 2007

There are very few reports in the literature of using pedicled flaps to revascularize distant tissue. Here, we describe the first description of using a radial artery perforator from a reverse radial forearm flap to revascularize a digit. Complex hand trauma presents multifaceted problems for the surgeon. This is illustrated by a recent case we treated of a severe hand crush injury, in which the two main problems were finger devascularization and a palmar defect. This required vein graft revascularization and local flap reconstruction. The initial management failed, and instead of repeating the same procedures, a single elegant solution was found. A reversed radial forearm flap was used for soft tissue defect coverage of the palmar defect, while a radial artery perforator was isolated for digital revascularization. This technique may seem excessive for digital revascularization, but in the correct context it overcomes “zone of injury” issues in major hand trauma and allows simultaneous revascularization with soft tissue defect cover.
Effect of intramammary infection in Bergamasca meat sheep on milk parameters and lamb growth
Authors: Moroni Paolo , Pisoni Giuliano , Varisco Giorgio , Boettcher Paul
Published: April 2007

Pooled milk samples from 115 Bergamasca meat sheep were collected aseptically five times from lambing to weaning to determine the prevalence of intramammary infection, somatic cell counts and milk quality parameters (protein, fat and lactose), and effects of infection on lamb weight gain. The global prevalence of subclinical intramammary infection was 51·2%. The Staphylococcus genus was responsible for the greatest prevalence (53·3% among infected udders). Staphylococcus aureus was isolated in 8·4% of infected milk samples. Infection status had significant effects on fat and protein percentage and on somatic cell count. Lamb growth was greatest for lambs of ewes with no infection and decreased as the number of infected samples increased. No significant differences were detected in the growth of lambs with dams infected by different bacterial species.
Interaction between parallel Gaussian electromagnetic beams in ionic collision dominated plasmas with thermal conduction
Authors: SODHA MAHENDRA SINGH , AGARWAL SUJEET KUMAR , SHARMA ASHUTOSH
Published: April 2007

In this communication the interaction between two Gaussian electromagnetic beams in an ionic collision dominated plasma has been investigated, when the axes of the two beams are initially (z = 0) parallel along the z-axis in the xz plane; the beams are initially propagating in the z-direction. Taking into account the loss of electron energy by collisions and by thermal conduction, the energy balance equation for electrons has been solved to obtain the space dependence of the electron temperature and the dielectric function has been expressed as a function of the electron temperature; this expression for the dielectric function has been substituted in the wave equation and a solution of the resulting nonlinear equation obtained in the paraxial approximation. Second-order coupled ordinary differential equations have been obtained for the distance between the centers of the beams and the beam widths in the x- and y-directions as a function of the distance of propagation along the z-axis. The equations have been solved numerically for a range of parameters and a discussion of the results is presented for the case when the two beams have the same axial irradiance, frequency and width. From simple considerations it is seen that the beams attract each other when 2xo < wro and in this situation beams are close enough for the paraxial approximation to be valid.
Inhibitory deficits for negative information in persons with major depressive disorder
Authors: LAU MARK A. , CHRISTENSEN BRUCE K. , HAWLEY LANCE L. , GEMAR MICHAEL S. , SEGAL ZINDEL V.
Published: April 2007

Background

Within Beck's cognitive model of depression, little is known about the mechanism(s) by which activated self-schemas result in the production of negative thoughts. Recent research has demonstrated that inhibitory dysfunction is present in depression, and this deficit is likely valence-specific. However, whether valence-specific inhibitory deficits are associated with increased negative cognition and whether such deficits are specific to depression per se remains unexamined. The authors posit the theory that inhibitory dysfunction may influence the degree to which activated self-schemas result in the production of depressive cognition.

Method

Individuals with major depressive disorder (MDD, n=43) versus healthy (n=36) and non-depressed anxious (n=32) controls were assessed on the Prose Distraction Task (PDT), a measure of cognitive inhibition, and the Stop-Signal Task (SST), a measure of motor response inhibition. These two tasks were modified in order to present emotionally valenced semantic stimuli (i.e. negative, neutral, positive).

Results

Participants with MDD demonstrated performance impairments on the PDT, which were most pronounced for negatively valenced adjectives, relative to both control groups. Moreover, these impairments correlated with self-report measures of negative thinking and rumination. Conversely, the performance of the MDD participants did not differ from either control group on the SST.

Conclusions

Implications of these findings for understanding the mechanisms underlying the development and maintenance of depressive cognition are discussed.
Recruitment dynamics and ectomycorrhizal colonization of Dicymbe corymbosa, a monodominant tree in the Guiana Shield
Authors: McGuire Krista L.
Published: April 2007

The dynamics of early life-history stages are important for understanding regional diversity patterns in tropical trees. In this study, patterns of seed removal, seedling survival and ectomycorrhizal (ECM) colonization in monodominant and mixed tropical rain forests in Guyana were investigated during a masting event of an ECM monodominant tree, Dicymbe corymbosa. Two seed densities (1 m−2 and 6 m−2) were tested in two forest types (monodominant versus mixed) with 10 plots per treatment (40 plots total). Germination success, seed and seedling survival after 1 y were measured for the monodominant tree, and four non-dominant canopy tree species found in both forest types (Eschweilera sagotiana, Licania laxiflora, Chrysophyllum sanguinolentum and Carapa guianensis). A significant effect of forest type was detected for seed removal and seedling survival. In the mixed forest, seed removal was higher for all species, with 27% average removal compared with 7% average seed removal in the monodominant forest. Germination success was significantly lower for all but one species in the mixed forest, with average germination of 41% compared with 78% germination in the monodominant forest. Seed and seedling survival of the monodominant tree was greatest within the monodominant forest with 93% of seeds germinating and 85% of seedlings surviving after 1 y compared with 65% germination and 15% seedling survival in the mixed forest. Per cent ectomycorrhizal colonization of Dicymbe corymbosa was near 100% in the monodominant forest, but significantly lower (14%) in the mixed forest. These results suggest that seedling survival patterns, rather than seed survival, are more important for recruitment success in this system and that ectomycorrhizal inoculum may limit establishment of Dicymbe corymbosa in the mixed forest.
Bruchid beetle infestation and the value of Attalea butyracea endocarps for neotropical rodents
Authors: Gálvez Dumas , Jansen Patrick A.
Published: April 2007

Frugivorous and granivorous vertebrates often discriminate against seeds and fruits infested by insects (Sallabanks & Courtney 1992). Insects may actively render seed or fruit unpalatable or unusable to vertebrates as a strategy to maximize the amount of food available to themselves (Janzen 1977). Nevertheless, vertebrates sometimes do not differentiate between sound and infested seeds or fruits (Dixon et al. 1997, Weckerly et al. 1989), or even prefer insect-infested seeds and fruits to sound ones (Sallabanks & Courtney 1992, Semel & Andersen 1988, Steele et al. 1996, Valburg 1992). Possible reasons for vertebrates to prefer infested seeds include: (1) seeds with larvae having a higher nutritional value than sound ones, because larvae synthesize fat and/or proteins (Sallabanks & Courtney 1992, Valburg 1992) or other nutrients such as vitamins (Havera & Smith 1979, Semel & Andersen 1988, Steele et al. 1996); (2) seeds with larvae tasting better than sound seeds (Borowicz 1988); and (3) seeds with larvae may be more easily opened and consumed than sound seeds (Borowicz 1988).
Carbon and nutrient stocks in roots of forests at different altitudes in the Ecuadorian Andes
Authors: Soethe Nathalie , Lehmann Johannes , Engels Christof
Published: April 2007

Carbon and nutrient stocks in below-ground biomass have rarely been investigated in tropical montane forests. In the present study, the amounts of carbon, nitrogen, phosphorus, sulphur, potassium, calcium and magnesium in root biomass were determined by soil coring and nutrient analysis in forests at three altitudes (1900, 2400 and 3000 m) in the Ecuadorian Andes. Root biomass increased markedly from 2.8 kg m−2 at 1900 m and 4.0 kg m−2 at 2400 to 6.8 kg m−2 at 3000 m. The contribution of coarse roots (> 2 mm in diameter) to total root biomass increased from about 70% at 1900 m to about 80% at higher altitudes. In fine roots (≤ 2 mm in diameter), concentrations of nutrients except calcium markedly decreased with altitude. Therefore, the nutrient stocks in fine roots were similar at 1900 m and 3000 m for nitrogen and sulphur, and were even lower at higher altitudes for phosphorus, potassium and magnesium. In coarse roots of Graffenrieda emarginata concentrations of nutrients were substantially lower than in fine roots, and were little affected by altitude. The data suggest that the importance of coarse roots for long-term carbon and nutrient accumulation in total plant biomass increases with increasing altitude.
Trenching increased growth, and irrigation increased survival of tree seedlings in the understorey of a semi-evergreen rain forest in Panama
Authors: Tanner Edmund V. J. , Barberis Ignacio M.
Published: April 2007

Seedlings in tropical forests are ultimately the source of canopy trees, thus factors controlling their composition and growth potentially influence the composition of the forest. Seedlings are primarily limited by above-ground competition with trees, but below-ground competition is potentially also important. Over 4 y we experimentally reduced below-ground competition by trenching to 50 cm and reduced drought stress by irrigating in the dry seasons (6 cm every 2 d) in the understorey of a semi-evergreen rain forest in Panama. There were four irrigated plots and four unirrigated, in each plot there were eight subplots (four trenched, four untrenched); 32 seedlings (two per subplot) of each of four tree species were equally allocated to the four treaments; the four species were: Aspidosperma cruenta; Gustavia superba; Simarouba amara and Tachigali versicolor. Over all species together, trenching increased seedling height by 41% and leaf area by 140% over 4 y. The cause was likely to be increased nutrient supply, because the amounts of N, K and Ca were higher in trenched plants, though concentrations were not higher. Irrigation had no significant effect on growth. Irrigation, but not trenching, reduced seedling mortality. We conclude that below-ground competition was a major limitation for seedling growth for at least some common species (Gustavia and Tachigali in this experiment). More experiments are necessary to determine whether below-ground competition is also important in other tropical rain forests on fairly fertile soils.
Modelling atmospheric flows
Authors: Cullen Mike
Published: April 2007

This article demonstrates how numerical methods for atmospheric models can be validated by showing that they give the theoretically predicted rate of convergence to relevant asymptotic limit solutions. This procedure is necessary because the exact solution of the Navier–Stokes equations cannot be resolved by production models. The limit solutions chosen are those most important for weather and climate prediction. While the best numerical algorithms for this purpose largely reflect current practice, some important limit solutions cannot be captured by existing methods. The use of Lagrangian rather than Eulerian averaging may be required in these cases.
Austrian Breast and Colorectal Cancer Study Group (ABCSG)
Authors:   The Breast International Group
Published: April 2007

This section provides current contact details and a summary of recent or ongoing clinical trials being coordinated by Austrian Breast and Colorectal Cancer Study Group ABCSG. Clinical trials include:

Adjuvant therapy with CMF versus goserelin plus tamoxifen in pre-menopausal, hormone-responsive, lymph node-positive or -negative patients. Study 5

Adjuvant endocrine therapy in postmenopausal patients with hormone-responsive breast cancer: tamoxifen versus tamoxifen plus aminoglutethimide. Study 6

Pre and postoperative chemotherapy versus conventional adjuvant chemotherapy alone in patients presenting with hormone receptor-negative breast cancer. Study 7

Adjuvant endocrine therapy in postmenopausal patients with hormone-responsive breast cancer, G1 and G2 (ARNO). Study 8

Adjuvant chemotherapy in postmenopausal patients with hormone-responsive breast cancer, G3. Study 9

Adjuvant endocrine therapy and bisphosphonate therapy: tamoxifen in comparison to anastrozole, alone or in combination with zoledronate, in premenopausal patients presenting with hormone-responsive, Stage I and II breast cancer. Study 12

Effect of 3 versus 6 cycles of epidoxorubicin/docetaxel G-CSF upon the rate of complete pathological remissions in the neoadjuvant treatment of patients with primary breast cancer and no distant metastases. Study 14

SALSA (Secondary Adjuvant Long-term Study with Arimidex): a prospective, randomized, open, multicentre Phase III study to assess the efficacy of secondary adjuvant endocrine anastrozole therapy for 2 further years versus 5 further years in patients with hormone receptor-positive breast cancer after a 5-year primary adjuvant endocrine therapy. Study 16

Neoadjuvant hormonal therapy with exemestane in postmenopausal patients with primary hormone receptor-positive breast cancer and no distant metastases. Study 17

A randomized, double-blind, placebo-controlled, multi-centre phase 3 study to determine the treatment effect of denosumab in subjects with non-metastatic breast cancer receiving aromatase inhibitor therapy. Study 18

A randomised Phase II study comparing anastrozole and fulvestrant to anastrozole for adjuvant treatment of postmenopausal patients with early breast cancer and disseminated tumour cells in bone marrow. Study 21

A randomized Phase III study comparing epirubicin, docetaxel and capecitabine G-CSF to epirubicin and docetaxel G-CSF as neoadjuvant treatment for early HER-2 negative breast cancer and comparing epirubicin, docetaxel and capecitabine G-CSF trastuzumab to epirubicin and docetaxel G-CSF trastuzumab as neoadjuvant treatment for early HER-2 positive breast cancer. Study 24
Adjuvant Tamoxifen – Longer Against Shorter (ATLAS)
Authors:   The Breast International Group
Published: April 2007

This section provides current contact details and a summary of recent or ongoing clinical trials being coordinated by Adjuvant tamoxifen – longer against shorter (ATLAS). Clinical trials include:

Phase III ATLAS adjuvant tamoxifen – longer against shorter: an international trial of adjuvant hormonal treatment duration (www.ctsu.ox.ac.uk/~atlas/index.html).
Danish Breast Cancer Cooperative Group (DBCG)
Authors:   The Breast International Group
Published: April 2007

This section provides current contact details and a list of recent or ongoing clinical trials that the Danish Breast Cancer Cooperative Group (DBCG) participate in with other clinical trials groups, if applicable.
Fondazione Michelangelo Breast Cancer Group (FM-B)
Authors:   The Breast International Group
Published: April 2007

This section provides current contact details and a summary of recent or ongoing clinical trials being coordinated by Fondazione Michelangelo Breast Cancer Group (FM-B). Clinical trials include:

European cooperative study of chemotherapy and surgery comparing adjuvant doxorubicin followed by CMF versus adjuvant doxorubicin/paclitaxel followed by CMF versus primary doxorubicin/paclitaxel followed by CMF in women with operable breast cancer and T > 2cm.

European Cooperative Study of Primary Systemic Therapy in Women with Operable Breast Cancer and T > 2cm.
Grupo de Estudios Clínicos Oncológicos del Perú (GECO PERU)
Authors:   The Breast International Group
Published: April 2007

This section provides current contact details and a summary of recent or ongoing clinical trials being coordinated by Grupo de Estudios Clínicos Oncológicos del Perú (GECO PERU). Clinical trials include:

Determination of prognostic factors in the outcome to a metronomic treatment with low doses of cyclophosphamide and methotrexate in patients with advanced breast cancer.
Chilean Cooperative Group for Oncologic Research (GOCCHI)
Authors:   The Breast International Group
Published: April 2007

This section provides current contact details and a summary of recent or ongoing clinical trials being coordinated by Chilean Cooperative Group for Oncologic Research (GOCCHI). Clinical trials include:

Molecular marker for dissemination in breast carcinoma.
Hellenic Breast Surgical Society (HBSS)
Authors:   The Breast International Group
Published: April 2007

This section provides current contact details and a list of recent or ongoing clinical trials that the Hellenic Breast Surgical Society (HBSS) participate in with other clinical trials groups, if applicable.
National Surgical Adjuvant Breast and Bowel Project (NSABP)
Authors:   The Breast International Group
Published: April 2007

This section provides current contact details and a summary of recent or ongoing clinical trials being coordinated by National Surgical Adjuvant Breast and Bowel Project (NSABP). Clinical trials include:

NSABP B-35 – A clinical trial comparing anastrozole with tamoxifen in postmenopausal patients with ductal carcinoma in situ (DCIS) undergoing lumpectomy with radiation therapy.

NSABP B-36 – A clinical trial of adjuvant therapy comparing six cycles of 5-fluorouracil, epirubicin and cyclophosphamide (FEC) to four cycles of adriamycin and cyclophosphamide (AC) in patients with node-negative breast cancer.

NSABP B-38 – A phase III, adjuvant trial comparing three chemotherapy regimens in women with node-positive breast cancer: docetaxel/doxorubicin/cyclophosphamide (TAC); dose-dense (DD) doxorubicin/cyclophosphamide followed by DD paclitaxel (DD AC→P): DD AC followed by DD paclitaxel plus gemcitabine (DD AC→PG).

NSABP B-39 – A randomized phase III study of conventional whole breast irradiation (WBI) versus partial breast irradiation (PBI) for women with stage 0, I, or II breast cancer.
Periodic structures with spin-orbit coupling
Authors: Demikhovskiĭ V. Ya. , Khomitsky D. V. , Perov A. A.
Published: April 2007

A study is made of the quantum states and spin polarization of a two-dimensional electron gas with spin-orbit coupling in an external period potential and in magnetic field. The influence of Rashba and Dresselhaus spin-orbit coupling on the band structure, wave functions, and spin-density distribution is studied for a two-dimensional electron gas in the field of a one-dimensional lateral superlattice. The calculations take into account the modulation of the Rashba parameter by the periodic potential of the superlattice. The Harper-Hofstadter problem is solved for a two-dimensional electron gas with spin-orbit coupling in the field of a periodic two-dimensional potential and in a perpendicular magnetic field. The band spectrum, wave functions, and spin-density distribution of the electron gas are found. The dispersion relations in the magnetic subbands, the spin densities, and the mean values of the spins are calculated for different values of the number of magnetic flux quanta through the unit cell of the superlattice, with Rashba spin-orbit coupling and the Zeeman splitting taken into account.
Vertical transport in a GaInAsSb∕p-InAs broken-gap type II heterojunction
Authors: Berezovets V. A. , Moiseev K. D. , Mikhailova M. P. , Parfeniev R. V. , Yakovlev Yu. P. , Nizhankovski V. I.
Published: April 2007

The formation of self-consistent quantum wells for electrons and holes in a P(N)-GaInAsSb∕p-InAs broken-gap type II heterojunction with an abrupt planar interface (a transition layer of the order of 1.2nm thick) upon variation of the type and level of doping of the semiconductors in contact is controlled by the overlap of the energy bands at the heterointerface. In a study of the vertical magnetotransport through a GaInAsSb∕p-InAs broken-gap type II heterointerface it is shown that the increase of the localization of the two-dimensional electrons in the electron channel at the interface leads to the formation of a “soft” Coulomb gap in the tunneling density of states. In magnetic fields below 15T at helium temperature a transition from the state with a “soft” Coulomb gap to an insulator state (a hard energy gap at a conductance value of σtun∼10−8Ω−1) is observed under the condition that the Fermi level for the two-dimensional electrons lies in the interval between the lowest Landau levels for the ν=2 plateau on the ρxy curve. As the external bias across the heterojunction is increased, the threshold offset from the insulator state is due to one-electron tunneling between individual closed regions of extended electronic states of the Landau level closest to the Fermi level.
Laser absorption, mass ablation rate, and shock heating in direct-drive inertial confinement fusion
Authors: Regan S. P. , Epstein R. , Goncharov V. N. , Igumenshchev I. V. , Li D. , Radha P. B. , Sawada H. , Seka W. , Boehly T. R. , Delettrez J. A. , Gotchev O. V. , Knauer J. P. , Marozas J. A. , Marshall F. J. , McCrory R. L. , McKenty P. W. , Meyerhofer D. D. , Sangster T. C. , Shvarts D. , Skupsky S. , Smalyuk V. A. , Yaakobi B. , Mancini R. C.
Published: April 2007

Direct-drive laser absorption, mass ablation rate, and shock heating are experimentally studied on the OMEGA Laser System [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] to validate hydrodynamics simulations. High-gain, direct-drive inertial confinement fusion target implosions require accurate predictions of the shell adiabat α (entropy), defined as the pressure in the main fuel layer to the Fermi-degenerate pressure, and the implosion velocity of the shell. The laser pulse shape determines the shell adiabat and the hydrodynamic efficiency determines the implosion velocity. A comprehensive set of measurements tracking the flow of energy from the laser to the target was conducted. Time-resolved measurements of laser absorption in the corona are performed on spherical implosion experiments. The mass ablation rate is inferred from time-resolved Ti K-shell spectroscopic measurements of nonaccelerating, solid CH spherical targets with a buried tracer layer of Ti. Shock heating is diagnosed in planar-CH-foil targets using time-resolved x-ray absorption spectroscopy and noncollective spectrally resolved x-ray scattering. The highly reproducible experimental results achieved with a high level of laser drive uniformity [S. P. Regan et al., J. Opt. Soc. Am. B 22, 998 (2005)] constrain the modeling of direct-drive energy coupling. A detailed comparison of the experimental results and the simulations reveals that a single-value flux limiter in the thermal transport model cannot explain all of the experimental observables. Simulations of laser absorption measurements need a time-dependent flux limiter to match the data. Modeling of both resonance absorption and nonlocal effects in the electron thermal conduction from the critical density to the ablation front are underway to resolve the observed discrepancies.
Nuclear measurements of fuel-shell mix in inertial confinement fusion implosions at OMEGA
Authors: Rygg J. R. , Frenje J. A. , Li C. K. , Séguin F. H. , Petrasso R. D. , Delettrez J. A. , Glebov V. Yu. , Goncharov V. N. , Meyerhofer D. D. , Radha P. B. , Regan S. P. , Sangster T. C.
Published: April 2007

Direct drive spherical implosions on the OMEGA laser system [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] have shown that increased capsule convergence results in increased susceptibility to fuel-shell mix. Mix results from saturation of the Rayleigh-Taylor instability, leading to small-scale, turbulent eddies and atomic-level mixing of the high-density compressed shell with hot, low-density fuel from the core. To sensitively probe the extent of mix, nuclear yields were measured from implosions of capsules filled with pure He3. The plastic capsule shell contains a deuterated plastic (CD) layer either on the inner surface or offset from the inner surface by 1μm. Mixing of D from the shell with hot He3 in the core is necessary to produce 14.7MeV DHe3 protons in such capsules. DHe3-proton spectral measurements have been used to constrain the amount of mix at shock time, to demonstrate that some of the fuel mixes with the offset CD layer, and that capsules with a higher initial fill density or thicker shell are less susceptible to the effects of mix.
Quasiequilibrium gas of magnons with a nonzero chemical potential: A way to Bose-Einstein condensation
Authors: Dzyapko O. , Demidov V. E. , Demokritov S. O. , Melkov G. A. , Slavin A. N.
Published: April 2007

A gas of thermalized quasiequilibrium magnons with a nonzero chemical potential is created in an yttrium iron garnet film using parametric pumping. The value of the chemical potential is determined directly by detection of the statistic distribution of magnons over the spectrum. With increasing pumping power, the value of the chemical potential increases. At high pumping powers, it can reach the energy corresponding to the lowest magnon frequency. Under these conditions, a very narrow peak of magnon population at the lowest magnon frequency is created. We associate this peak with Bose-Einstein condensation of magnons.
Intergranular interactions of low temperature atmosphere annealed Co∕Pd magnetic multilayers
Authors: E Chunsheng , Rantschler James , Zhang Shishan , Smith Darren , Parekh Vishal , Khizroev Sakhrat , Lee T. Randall , Litvinov Dmitri
Published: April 2007

We present evidence that low temperature atmosphere annealing of Co∕Pd magnetic multilayers reduces both the dipolar and exchange interactions, but the dipolar interaction decreases very rapidly at the lowest temperatures. We also infer cobalt oxide formation at grain boundaries. This results in a reduction of the exchange between grains, reduces the length scale of ordering in the ac demagnetized state of the films. We demonstrate that this is the result of the decoupling the grains.
One-pot sonochemical synthesis of Fe1−xCuxCr2S4 chalcospinels
Authors: Rao Manju Lata , Manoharan S. Sundar
Published: April 2007

We present a simple and convenient one step route to prepare a series of chalcospinels Fe1−xCuxCr2S4 employing high frequency sound waves. The magnetic and electronic transport properties of the as-prepared spinels were studied, and this simple, easy, and efficient synthetic route may further encourage wider application of Cu-doped Fe chalcogenides in solid state magnetoelectronic devices. Furthermore, the adopted synthetic route highlights a one-pot synthesis employing organometallic precursors such as metal carbonyls, ethylenedimine, and elemental sulfur. The ease of synthesizing such complex spinel structures of Fe1−xCuxCr2S4 chalcogenides with x=0.3, 0.4, and 0.6 has been highlighted in this work. The rapid cavitational collapse results in sulfur deficiency in the system, which drastically alters the conduction behavior. All the compositions studied show a negative magnetoresistance response except for x=0.3 which exhibit an unusual positive magnetoresistance effect. Such an effect has been attributed to the sulfur deficiency occurring during the rapid cavitational collapse. Our experimental results provide one effective method for synthesis of doped ternary chalcospinels exhibiting magnetoresistive properties.
Classification of modules of the intermediate series over Ramond N=2 superconformal algebras
Authors: Fu Jiayuan , Jiang Qifen , Su Yucai
Published: April 2007

In this paper, we first discuss the structure of the Ramond N=2 superconformal algebras. Then we classify the modules of the intermediate series over Ramond N=2 superconformal algebra.
Elastic torsional responses of carbon nanotube systems
Authors: Jeong Byeong-Woo , Lim Jang-Keun , Sinnott Susan B.
Published: April 2007

The mechanical responses of several different carbon nanotube systems to applied torsional loading at various temperatures are examined using classical molecular dynamics simulations, and the results are interpreted and compared to the predictions of continuum mechanics theory. The specific materials considered include filled and chemically functionalized, individual single-walled and multiwalled carbon nanotubes, as well as bundled carbon nanotubes. The simulations indicate that the mechanical responses to the torsional loading are buckling and that all the carbon nanotube systems considered are highly elastic. They also indicate that the critical buckling moment can be increased by the presence of filling materials and inner carbon nanotubes, and that the amount of this increase depends on the kind of filling materials and the number of inner tubes. The simulations further show that the critical buckling moment of a single carbon nanotube in a bundle is higher than that of the individual nanotubes alone. In addition, the dependence of the torsional stiffness on the diameters of the nanotubes is found to vary as K∼D2.99, where K is the torsional stiffness and D is the nanotube diameter, and the torsional shear modulus is found to be relatively independent of the nanotube diameter and length, in good agreement with predictions from continuum mechanics theory. Lastly, the simulations indicate that the critical buckling moment can be modified by adjusting the system temperature and through chemical functionalization of the carbon nanotube walls.
Modification of the N bonding environment in GaN after high-dose Si implantation: An x-ray absorption study
Authors: Katsikini M. , Pinakidou F. , Paloura E. C. , Boscherini F.
Published: April 2007

The microstructure and electronic structure of epitaxially grown GaN, that has been subjected to high-dose Si implantation, is studied using x-ray absorption fine structure (XAFS) spectroscopy. More specifically, XAFS is used to probe the formation of N–Si bonds and to study the implantation induced distortions in the lattice. The analysis of the extended XAFS spectra reveals that implantation with 100keV Si ions with a fluence equal to 1×1018cm−2 renders the material amorphous and promotes the formation of Si–N bonds with a bond length equal to that corresponding in Si3N4. In addition to that, the N–Ga distances increase by ∼5% due to the lattice expansion caused by the incorporation of the Si ions and the formation of point and extended defects. The absence of long or midrange order is also verified by the near edge XAFS (NEXAFS) spectra where the characteristic peaks are smeared out. However, a characteristic sharp resonance line, that appears about 1eV above the absorption edge, indicates the existence of defect states which are strongly localized on the N atoms, most probably defect complexes involving N dangling bonds. In order to provide additional evidence on the nature of the implantation induced changes we resorted to simulations of the NEXAFS spectra using the FEFF8 code by applying chemical and lattice deformations in the immediate environment of the absorbing atom as well as to larger clusters.
Comparative study of water dissociation on Rh(111) and Ni(111) studied with first principles calculations
Authors: Pozzo Monica , Carlini Gianluigi , Rosei Renzo , Alfè Dario
Published: April 2007

The dissociation and formation of water on the Rh(111) and Ni(111) surfaces have been studied using density functional theory with generalized gradient approximation and ultrasoft pseudopotentials. Calculations have been performed on 2×2 surface unit cells, corresponding to coverages of 0.25 ML, with spot checks on 3×3 surface unit cells (0.11 ML). On both surfaces, the authors find that water adsorbs flat on top of a surface atom, with binding energies of 0.35 and 0.25eV, respectively, on Rh(111) and Ni(111), and is free to rotate in the surface plane. Barriers of 0.92 and 0.89eV have to be overcome to dissociate the molecule into OH and H on the Rh(111) and Ni(111) surfaces, respectively. Further barriers of 1.03 and 0.97eV need to be overcome to dissociate OH into O and H. The barriers for the formation of the OH molecule from isolated adsorbed O and H are found to be 1.1 and 1.3eV, and the barriers for the formation of the water molecule from isolated adsorbed OH and H are 0.82 and 1.05eV on the two surfaces. These barriers are found to vary very little as coverage is changed from 0.25 to 0.11 ML. The authors have also studied the dissociation of OH in the presence of coadsorbed H or O. The presence of a coadsorbed H atom only weakly affects the energy barriers, but the effect of O is significant, changing the dissociation barrier from 1.03 to 1.37 and 1.15eV at 0.25 or 0.11 ML coverage on the Rh(111) surface. Finally, the authors have studied the dissociation of water in the presence of one O atom on Rh(111), at 0.11 ML coverage, and the authors find a barrier of 0.56eV to dissociate the molecule into OH+OH.
Low voltage energy-saving double-walled carbon nanotube electric lamps
Authors: Shu Q. K. , Wei J. Q. , Wang K. L. , Li C. G. , Jia Y. , Wu D. H.
Published: April 2007

The relative efficacy of electric lamps with double-walled carbon nanotube (DWNT) filaments is higher than that with tungsten filaments at the same input power. The luminescence of DWNT electric lamps shows a cold light performance besides blackbody radiation. At a color temperature of 2386 K, the visible light emitted by the DWNT electric lamp (filament diameter: 0.06 mm) occupies 7.6% of the total radiation energy, higher than that of tungsten lamps. The longevity of the DWNT electric lamp (filament diameter: 0.15 mm, 15 V) is no less than 3000 h. DWNT electric lamps are energy saving at low voltages and have potential applications.
Massive spalling of intermetallic compounds in solder-substrate reactions due to limited supply of the active element
Authors: Yang S. C. , Ho C. E. , Chang C. W. , Kao C. R.
Published: April 2007

Massive spalling of intermetallic compounds has been reported in the literature for several solder/substrate systems, including SnAgCu soldered on Ni substrate, SnZn on Cu, high-Pb PbSn on Cu, and high-Pb PbSn on Ni. In this work, a unified thermodynamic argument is proposed to explain this rather unusual phenomenon. According to this argument, two necessary conditions must be met. The number one condition is that at least one of the reactive constituents of the solder must be present in a limited amount, and the second condition is that the soldering reaction has to be very sensitive to its concentration. With the growth of intermetallic, more and more atoms of this constituent are extracted out of the solder and incorporated into the intermetallic. As the concentration of this constituent decreases, the original intermetallic at the interface becomes a nonequilibrium phase, and the spalling of the original intermetallic occurs.
Numerical study on two-phase flow patterns in coaxial electrospinning
Authors: Hu Yingying , Huang Zheng-Ming
Published: April 2007

To study two-phase flows occurring in the process of coaxially electrospinning core-shell composite nanofibers, a mathematic physical model was proposed with shear-thinning fluid properties, surface tension, and electric fields specially considered. Numerical results showed three flow patterns: slug, slug-annular transitional, and annular flows. According to a flow pattern model based on the Weber number, slug-annular transitional flows were predicted to occur when the Weber number was between 0.5 and 26, whereas the slug and annular flows were to be expected when the Weber number was less than 0.5 and greater than 26, respectively. Body forces (induced by electric fields) and surface tension forces had more explicit effects on the flow patterns than forces due to viscosity and permeability gradients on interfaces. To form an annular flow pattern with smooth core-shell interfaces, which is favored in engineering practice, the applied electric field should be stronger than 100 kv/m.