bluuebunny/crossref_metadata_2025_split huggingface dataset:
Information theory and hypothesis testing: a call for pluralism
Authors: STEPHENS PHILIP A. , BUSKIRK STEVEN W. , HAYWARD GREGORY D. , MARTÍNEZ DEL RIO CARLOS 
Published: February 2005

Summary

A major paradigm shift is occurring in the approach of ecologists to statistical analysis. The use of the traditional approach of null‐hypothesis testing has been questioned and an alternative, model selection by information–theoretic methods, has been strongly promoted and is now widely used. For certain types of analysis, information–theoretic approaches offer powerful and compelling advantages over null‐hypothesis testing.
The benefits of information–theoretic methods are often framed as criticisms of null‐hypothesis testing. We argue that many of these criticisms are neither irremediable nor always fair. Many are criticisms of the paradigm's application, rather than of its formulation. Information–theoretic methods are equally vulnerable to many such misuses. Care must be taken in the use of either approach but users of null‐hypothesis tests, in particular, must greatly improve standards of reporting and interpretation.
Recent critiques have suggested that the distinction between experimental and observational studies defines the limits of the utility of null‐hypothesis testing (with the paradigm being applicable to the former but not the latter). However, we believe that there are many situations in which observational data are collected that lend themselves to analysis under the null‐hypothesis testing paradigm. We suggest that the applicability of the two analytical paradigms is more accurately defined by studies that assess univariate causality (when null‐hypothesis testing is adequate) and those that assess multivariate patterns of causality (when information–theoretic methods are more suitable).
Synthesis and applications. Many ecologists are confused about the circumstances under which different inferential paradigms might apply. We address some of the major criticisms of the null‐hypothesis testing paradigm, assess those criticisms in relation to the information–theoretic paradigm, propose methods for improving the use of null‐hypothesis testing, and discuss situations in which the use of null‐hypothesis testing would be appropriate. We urge instructors and practitioners of statistical methods to heighten awareness of the limitations of null‐hypothesis testing and to use information–theoretic methods whenever prior evidence suggests that multiple research hypotheses are plausible. We contend, however, that by marginalizing the use of null‐hypothesis testing, ecologists risk rejecting a powerful, informative and well‐established analytical tool.
Simple optimization procedure for objective lens correction collar setting
Authors: SCHWERTNER M. , BOOTH M. J. , WILSON T. 
Published: February 2005

SummaryWe present a new method for setting a coverglass correction collar on an objective lens. Axial scans across the interface between the specimen volume and the slide are used together with a quantitative function of merit to determine the optimum setting of the correction collar. The method, which simplifies the adjustment for the user and reduces photobleaching, was implemented within the software environment of a scanning microscope system.
Two‐photon excitation and emission spectra of the green fluorescent protein variants ECFP, EGFP and EYFP
Authors: SPIESS E. , BESTVATER F. , HECKEL‐POMPEY A. , TOTH K. , HACKER M. , STOBRAWA G. , FEURER T. , WOTZLAW C. , BERCHNER‐PFANNSCHMIDT U. , PORWOL T. , ACKER H. 
Published: February 2005

SummaryTwo‐photon (TP) excitation (820–1150 nm) and emission (280–700 nm) spectra for the fluorescent proteins (FPs) ECFP3, EGFP3 and EYFP3 produced in human tumour cells were recorded. TP excitation spectra of pure and highly enriched samples were found to be more differentiated in comparison with their one‐photon (OP) spectra. They exhibited more pronounced main and local maxima, which coincided among different purity grades within small limits. TP and OP emission spectra of pure and enriched samples were identical. However, in crude samples, excitation was slightly blue‐shifted and emission red‐shifted. The data indicate that both OP and TP excitation routes led to the same excited states of these molecules. The emission intensity is dependent on the pH of the environment for both types of excitation; the emission intensity maximum can be recorded in the alkaline range. Reconstitution of emission intensity after pH quenching was incomplete, albeit that the respective spectral profiles were identical to those prequenching. When emission data were averaged over the whole range of excitation, the resulting emission profile and maximum coincided with the data generated by optimal excitation. Therefore, out‐of‐maximum excitation, common practice in TP excitation microscopy, can be used for routine application.
Two‐photon excitation fluorescence pH detection using 2,3‐dicyanohydroquinone: a spectral ratiometric approach
Authors: JÖBSIS P. D. , COMBS C. A. , BALABAN R. S. 
Published: February 2005

SummaryThe use of 2,3‐dicyanohydroquinone (DCHQ) as an emission ratiometric probe of pH in vitro and in fibroblast cells was evaluated using two‐photon excitation fluorescence microscopy (TPEFM). In addition, methods for spectrally calibrating the Zeiss LSM510 META spectroscopy system for TPEFM were also developed. The emissions of both the acid and base forms of DCHQ were detectable when using an 800‐nm excitation in TPEFM, thereby allowing ratiometric determination of pH. These data suggest that, in contrast to most other emission ratiometric probes, both acid and base forms of DCHQ have similar two‐photon cross‐sectional areas at 800 nm. Acid (maximum at ∼457 nm) and base (maximum at ∼489 nm) DCHQ TPEFM emission spectra were similar to previously reported one‐photon excitation emission spectra. Calibration curves for pH were successfully constructed using the ratio of DCHQ emission difference maxima at 460 nm and 512 nm in vitro and in cells. To our knowledge, DCHQ is currently the only effective emission ratiometric pH indicator for two‐photon microscopy and may serve as a useful starting point for the development of other TPEFM ratiometric dyes for quantitative measurement of other cell parameters such as Ca2+, Mg2+ or Na+.
Third‐order aberration theory of Wien filters for monochromators and aberration correctors
Authors: TSUNO K. , IOANOVICIU D. , MARTÍNEZ G. 
Published: February 2005

SummaryThird‐order aberrations at the first and the second focus planes of double focus Wien filters are derived in terms of the following electric and magnetic field components – dipole: E1, B1; quadrupole: E2, B2; hexapole: E3, B3 and octupole: E4, B4. The aberration coefficients are expressed under the second‐order geometrical aberration free conditions of E2 = −(m + 2)E1/8R, B2 = −mB1/8R and E3R2/E1 − B3R2/B1 = m/16, where m is an arbitrary value common to all equations. Aberration figures under the conditions of zero x‐ and y‐axes values show very small probe size and similar patterns to those obtained using a previous numerical simulation [G. Martínez & K. Tsuno (2004) Ultramicroscopy, 100, 105–114]. Round beam conditions are obtained when B3 = 5m2B1/144R2 and (E4/E1 − B4/B1)R3 = −29m2/1152. In this special case, aberration figures contain only chromatic and aperture aberrations at the second focus. The chromatic aberrations become zero when m = 2 and aperture aberrations become zero when m = 1.101 and 10.899 at the second focus. Negative chromatic aberrations are obtained when m < 2 and negative aperture aberrations for m < 1.101. The Wien filter functions not only as a monochromator but also as a corrector of both chromatic and aperture aberrations. There are two advantages in using a Wien filter aberration corrector. First, there is the simplicity that derives from it being a single component aberration correction system. Secondly, the aberration in the off‐axis region varies very little from the on‐axis figures. These characteristics make the corrector very easy to operate.
A simple method allowing DIC imaging in conjunction with confocal microscopy
Authors: CODY S. H. , XIANG S. D. , LAYTON M. J. , HANDMAN E. , LAM M. H. C. , LAYTON J. E. , NICE E. C. , HEATH J. K. 
Published: February 2005

SummaryCurrent optical methods to collect Nomarski differential interference contrast (DIC) or phase images with a transmitted light detector (TLD) in conjunction with confocal laser scanning microscopy (CLSM) can be technically challenging and inefficient. We describe for the first time a simple method that combines the use of the commercial product QPm (Iatia, Melbourne Australia) with brightfield images collected with the TLD of a CLSM, generating DIC, phase, Zernike phase, dark‐field or Hoffman modulation contrast images. The brightfield images may be collected at the same time as the confocal images. This method also allows the calculation of contrast‐enhanced images from archival data. The technique described here allows for the creation of contrast‐enhanced images such as DIC or phase, without compromising the intensity or quality of confocal images collected simultaneously. Provided the confocal microscope is equipped with a motorized z‐drive and a TLD, no hardware or optical modifications are required. The contrast‐enhanced images are calculated with software using the quantitative phase‐amplitude microscopy technique (Barone‐Nugent et al., 2002). This technique, being far simpler during image collection, allows the microscopist to concentrate on their confocal imaging and experimental procedures. Unlike conventional DIC, this technique may be used to calculate DIC images when cells are imaged through plastic, and without the use of expensive strain‐free objective lenses.
Structural characterization of TiN/NbN multilayers: X‐ray diffraction, energy‐filtered TEM and Fresnel contrast techniques compared
Authors: LLOYD S. J. , MOLINA‐ALDAREGUIA J. M. , CLEGG W. J. 
Published: February 2005

SummaryTwo TiN/NbN multilayers with wavelength 13.6 and 6.15 nm have been characterized by X‐ray diffraction (XRD), Fresnel contrast analysis (FCA) and energy‐filtered transmission electron microscopy (EFTEM). Good agreement between the composition profile obtained by FCA and EFTEM is obtained if the lower resolution of the EFTEM images is taken into account. The relative advantages and disadvantages of the techniques are discussed. Used together the two TEM techniques provide a quantitative characterization that is consistent with, and for some parameters provides more precise values than, that from XRD. The analysis shows that the multilayers have narrow interfaces (< 1 nm) and a composition amplitude close to 95% for the longer wavelength.
Adequacy of outpatient management of asthma patients admitted to a state hospital in Argentina
Authors: RAIMONDI Guillermo A. , MENGA Guillermo , RIZZO Oscar , MERCURIO Sandra 
Published: February 2005

Objective:  The aim of this study was to assess chronic outpatient management of adult patients admitted with asthma.Methodology:  A cross‐sectional survey was conducted of 98 consecutive asthma admissions to a specialized pulmonary State Hospital in Buenos Aires, Argentina, over a 12‐month period. Patients were surveyed, within 48 h of admission, with a previously validated questionnaire which deals with chronic outpatient management and measures taken by patients or physicians to treat symptoms during asthma exacerbations.Results:  FEV1% predicted was 30.2 ± 10.7. Mean admission rate and emergency department (ED) visits in the previous year were 0.7 ± 1.2 and 4.6 ± 5.1, respectively. A total of 96, 65 and 9% of the patients had been treated previously in the ED, admitted to hospital or mechanically ventilated, respectively. Only 62% had been prescribed inhaled corticosteroids (IC) by their physician; 38% had been prescribed nebulized beta agonists (Nβ2) and 68% a metered dose inhaler (MDIβ2). Inhaled β2‐agonist usage during acute exacerbations over the 24 h prior to admission was 14.4 ± 7.4 puffs for MDIβ2 and 8.6 ± 5.4 occasions for Nβ2. Only 11% of the patients were able to perform all the steps of the MDI inhalation technique correctly. An action plan had been provided by their physicians to 43% of patients, while 58% changed their medication on their own. Only three patients had a peak flow meter (PFM) prescribed. ED was used by 26% for their routine care. No health insurance coverage was available to 75.5% of the patients.Conclusions:  Underuse of IC, poor MDI inhalation technique, and low prescription of an action plan was common and a PFM was seldom prescribed. During exacerbations, many patients changed their medication spontaneously and MDIβ2 underuse was observed.
The effect of a post acute respiratory outreach service for patients with chronic obstructive pulmonary disease on hospital readmission rates
Authors: JEFFS Kimberley J. , LIM Wen K. , LIM Michael , BERLOWITZ David J. , JACKSON Bruce 
Published: February 2005

Objective:  The aim of this study was to investigate the effect of a Post Acute Respiratory Outreach Service (PAROS) for patients with chronic obstructive pulmonary disease (COPD), on hospital utilization.Methods:  A retrospective cohort of patients was examined, using a nested comparison, to test the hypothesis that PAROS would affect hospital utilization in the 12 months following the intervention. Patients admitted with COPD and subsequently enrolled in PAROS were compared with age, sex and diagnosis‐matched controls admitted with COPD, who did not receive PAROS.Results:  Of 216 patients admitted with COPD during the 1‐year study period, 28 were referred to PAROS. A total of 25 suitable controls were identified. Three cases that could not be matched were excluded from the analysis. There were no significant differences in lung function or prior hospitalization between the two groups at baseline. A significant increase in hospital bed days, in the 12 months following the index admission, was observed in the PAROS group (P = 0.046). There was no difference in the number of admissions or emergency department presentations between the groups.Conclusions:  The PAROS program did not lead to a reduction in hospital utilization. This study supports previous findings that respiratory outreach services delivered immediately post discharge increase hospital utilization.
Safe and effective sedation and analgesia for bone marrow aspiration procedures in children with alfentanil, remifentanil and combinations with midazolam
Authors: Antmen Bülent , Şaşmaz Ilgen , Birbiçer Handan , Özbek Hayri , Burgut Refik , IşIk Geylan , Kilinç Yurdanur 
Published: February 2005

SummaryBackground : Invasive procedures such as bone marrow aspiration in children may be painful and cause anxiety. We investigated the efficacy and safety of remifentanil (R) alfentanil (A), remifentanil‐midazolam (RM), and alfentanil‐midazolam (AM) combinations in providing analgesia and sedation for bone marrow aspiration.Methods : Eighty children undergoing a diagnostic bone marrow aspiration whose ages ranged from 5–16 years (mean 9.20 ± 3.00  years) were enrolled in this study. The patients were randomly assigned to one of 4 treatment groups. Vital signs, sedation and pain scores, somatic responses (sweating and tears) were recorded before, during bone marrow aspiration and after 5 and 15 min of the procedure.Results : There were no statistical differences between sedation and the CHEOPS scores of the four groups during and after the procedures. The VAS scores were significantly higher for group A compared with groups R and RM during the procedure (P < 0.008). There were no differences between the VAS scores in group AM compared with groups R and RM (P > 0.008). There were also no statistical differences among the VAS scores of four groups after the procedure (P > 0.008). All patients had adequate sedation and analgesia. None of the patients in the study had deep sedation, hypotension, bradycardia, hypoxemia, or respiratory depression.Conclusions : Remifentanil, alfentanil, remifentanil‐midazolam, and alfentanil‐midazolam combinations are effective in children and can be used safely in bone marrow aspiration which is a brief but painful procedure performed in the pediatric patient group.
Perioperative care of the patient with Williams syndrome
Authors: MEDLEY JOHN , RUSSO PIERANTONIO , TOBIAS JOSEPH D. 
Published: February 2005

SummaryWilliams syndrome, initially described by Williams, Barratt–Boyes, and Lowe in 1961, consists of characteristic dysmorphic features, congenital heart disease, and distinctive behavioral and emotional traits. In addition to acquired and congenital heart disease, manifestations in the renal, endocrine, musculoskeletal, and central nervous system may have implications during the perioperative period. Congenital and acquired heart disease can be a significant issue as sudden death, related to abnormalities of the coronary arteries, has been reported perioperatively in these patients. The authors present a 7‐month‐old infant, previously diagnosed with Williams syndrome, who required anesthetic care for repair of subaortic and supravalvular aortic stenosis. The potential perioperative implications of Williams syndrome are discussed.
Dexmedetomidine as the primary sedative agent for brain radiation therapy in a 21‐month old child
Authors: SHUKRY MOHANAD , RAMADHYANI USHA 
Published: February 2005

SummaryDexmedetomidine (PrecedexTM) is an α2 adrenoceptor agonist which is gaining popularity as a sedative and anesthetic adjuvant. In this case report, dexmedetomidine was used safely and easily to provide sedation for 12 radiation‐therapy sessions in a pediatric patient. It provided smooth induction and fast recovery with minimal respiratory depression.
The ProSealTM laryngeal mask airway in children
Authors: LOPEZ‐GIL M. , BRIMACOMBE J. 
Published: February 2005

SummaryBackground : The ProSealTM (PLMA) is a new laryngeal mask device with a modified cuff to improve the seal and a drain tube to provide access to the gastrointestinal tract. We assessed the performance of the size 2 (which has no dorsal cuff) and size 3 (which has a dorsal cuff) in terms of insertion success, efficacy of seal, tidal volume, gas exchange, fiberoptic position, gastric tube placement and frequency of problems.Methods : Eighty children undergoing minor surgery were studied (n = 40, size 2 PLMA, weight 10–25 kg; n = 40, size 3 PLMA, weight >25–50 kg). Induction was with remifentanil and propofol. Insertion was with the introducer tool and by experienced users. Maintenance was with propofol or sevoflurane and pressure controlled ventilation.Results : The first‐time and overall insertion success rate was 84 and 100%, respectively. Oropharyngeal leak pressure was 31 ± 5 cmH2O. There were no gastric or drain tube air leaks. Tidal volume and gas exchange was adequate in all patients, other than two brief episodes of hypoxia because of airway reflex activation. The vocal cords and epiglottis were visible in 99 and 80%, respectively, via the airway tube. The first‐time and overall insertion success rate for gastric tube insertion was 87 and 100%, respectively. During maintenance, the PLMA was removed in one patient with airway reflex activation and another required epinephrine for bronchospasm. There were no differences in performance between the sizes 2 and 3 PLMA.Conclusion : The PLMA is an effective airway device in children and isolates the glottis from the esophagus when correctly positioned. Despite the lack of a dorsal cuff, the performance of the size 2 was similar to the size 3 PLMA in the age groups tested.
Pediatric sedation in North American children's hospitals: a survey of anesthesia providers
Authors: LALWANI KIRK , MICHEL MARLON 
Published: February 2005

SummaryBackground : Information about the existence and organization of pediatric sedation services in North America is not available. We conducted a survey to collect this information from anesthesiologists at pediatric institutions and to identify factors perceived as limiting the development of sedation services.Method : We electronically mailed a confidential survey about pediatric sedation practice to an attending anesthesiologist involved in pediatric sedation at 116 children's hospitals in the United States and Canada. We identified the institutions using Internet resources. Electronic mailing addresses were obtained from departmental websites, society membership directories and departmental administrators. Our follow‐up for nonresponders was by a second e‐mail and a telephone call.Results : A total of 54 completed questionnaires were received, a response rate of 47%. Forty‐nine (91%) were received from US hospitals, and the remainder from Canadian. Fifty percent of hospitals had a formal pediatric sedation service. Fifty‐four percent utilized a ‘mobile’ provider model. Hospital credentialing for nonanesthesiologist providers varied between 66 and 76% for ‘deep’ and ‘conscious’ sedation, respectively. A nurse–physician provider combination was the most common, utilized in 59% of hospitals. Anesthesiologists were the sole sedation providers in 26% of institutions. Propofol was used regularly by nonanesthesiologists for sedation of nonintubated (42%) and intubated (63%) patients. Eighty‐seven percent of institutions reported barriers to development of pediatric sedation services. The most common barrier was a shortage of providers, particularly anesthesiologists.Conclusions : Propofol use by nonanesthesiologists is common. Addressing the shortage of providers, and allocating resources for credentialing providers will encourage further development of pediatric sedation practice.
Children's drawings as a measure of anxiety level: a clinical pilot study
Authors: PUURA ARTO , PUURA KAIJA , RORARIUS MICHAEL , ANNILA PÄIVI , VIITANEN HANNA , BAER GERHARD 
Published: February 2005

SummaryBackground : No simple method exists to distinguish children in need for premedication. The present study was planned to detect preoperative anxiety levels of children by rating their drawings.Methods : Sixty ASA I children aged 4–7 years undergoing adenoidectomy were divided into AGIT and CALM groups according to agitation level observed during venous cannulation. All children drew a picture at three different times: (i) just after arrival in the day‐case unit, (ii) 10 min before operation and, (iii) prior to leaving for home. The children were also randomized to three premedication groups: group D, rectal diazepam 0.5 mg·kg−1; group P, 0.9% NaCl 0.1 ml·kg−1 rectally; group NT, no premedication. Five features (size of the drawing, form of the drawing line, colors used, mark of the pen and clarity of the picture) from the children's drawings were rated with a 3‐point scale. The ratings of each feature were made to form a sum score of anxiety ranging from 0 to 10. In the analysis of variance for repeated measures both the premedication group and agitation score were taken into the model as factors.Results : The anxiety score of the drawings of the agitated children (during venous cannulation) was significantly higher already after arrival in the hospital [AGIT 4.76 (95% CI: 3.56–5.96) Vs CALM 3.67 (95% CI: 2.97–4.37) P = 0.029], but there were no statistical differences between the different premedication groups.Conclusions : When routine sedative premedication is not used the drawings of the children might detect the children needing sedative premedication.
Recurrent life‐threatening bradycardia in a child with retained tracheal stent
Authors: JUAN CHUNG‐HAU , CHU CHI‐CHUN , CHANG WEN‐KEI , TSAI SHEN‐KOU 
Published: February 2005

SummaryWe report a child with a retained welded tracheal stent scheduled for removal developing refractory bradycardia and cardiac arrest during attempt to remove the stent. Cardiac massage and pacing were necessary to reestablish circulation. The same type of arrhythmia occurred three times in the postanesthetic care unit after tracheal suction or coughing.