Continental-scale tree-ring-based projection of Douglas-fir growth: Testing the limits of space-for-time substitution

A central challenge in global change research is the projection of the future behavior of a system based upon past observations. Tree-ring data have been used increasingly over the last decade to project tree growth and forest ecosystem vulnerability under future climate conditions. But how can the response of tree growth to past climate variation predict the future, when the future does not look like the past? Space-for-time substitution (SFTS) is one way to overcome the problem of extrapolation: the response at a given location in a warmer future is assumed to follow the response at a warmer location today. Here we evaluated an SFTS approach to projecting future growth of Douglas-fir (Pseudotsuga menziesii), a species that occupies an exceptionally large environmental space in North America. We fit a hierarchical mixed-effects model to capture ring-width variability in response to spatial and temporal variation in climate. We found opposing gradients for productivity and climate sensitivity with highest growth rates and weakest response to interannual climate variation in the mesic coastal part of Douglas-fir's range; narrower rings and stronger climate sensitivity occurred across the semi-arid interior. Ring-width response to spatial versus temporal temperature variation was opposite in sign, suggesting that spatial variation in productivity, caused by local adaptation and other slow processes, cannot be used to anticipate changes in productivity caused by rapid climate change. We thus substituted only climate sensitivities when projecting future tree growth. Growth declines were projected across much of Douglas-fir's distribution, with largest relative decreases in the semiarid U.S. Interior West and smallest in the mesic Pacific Northwest. We further highlight the strengths of mixed-effects modeling for reviving a conceptual cornerstone of dendroecology, Cook's 1987 aggregate growth model, and the great potential to use tree-ring networks and results as a calibration target for next-generation vegetation models.

Compression wood has a minor effect on the climate signal in tree-ring stable isotope records of montane Norway spruce

Compression wood (CW) is a common tissue present in the trunk, branches and roots of mechanically stressed coniferous trees. Its main role is to increase the mechanical strength and regain the vertical orientation of a leaning stem. Compression wood is thought to influence the climate signal in different tree-ring measures. Hence trees containing CW are mostly excluded from tree-ring studies reconstructing past climate variability. There is a large gap of systematic work testing the potential effect of CW on the strength of the climate signal in different tree-ring parameters, especially stable isotope records. Here we test for the first time the effect of CW contained in montane Norway spruce (Picea abies L. Karst) on both δ13C and δ18O tree-ring cellulose records by analyzing compression and opposite wood radii from several disturbed trees together with samples from undisturbed reference trees. We selected four trees tilted by geomorphic processes that were felled by wind and four undisturbed reference trees in the Tatra Mountains, Poland. We qualitatively classified the strength of CW using wood cell anatomical characteristics (tracheid shape, cell wall thickness and presence of intercellular spaces). Then we developed tree-ring width and δ13C and δ18O chronologies from the CW radii, from the opposite radii of the tilted trees and from the reference radii. We tested the effect of CW on tree-ring cellulose δ13C and δ18O variability and on the climate signal strength. We found only minor differences in the means of δ13C and δ18O of compression (δ13C: -22.81‰, δ18O: 28.29‰), opposite (δ13C: -23.02‰; δ18O: 28.05‰) and reference (δ13C: -22.78‰; δ18O: 27.61‰) radii. The statistical relationships between climate variables, δ13C and δ18O, remained consistent among all chronologies. Our findings suggest that moderately tilted trees containing CW can be used to reconstruct past geomorphic activity and for stable isotope-based dendroclimatology.

Tree growth influenced by warming winter climate and summer moisture availability in northern temperate forests

The role of future forests in global biogeochemical cycles will depend on how different tree species respond to climate. Interpreting the response of forest growth to climate change requires an understanding of the temporal and spatial patterns of seasonal climatic influences on the growth of common tree species. We constructed a new network of 310 tree-ring width chronologies from three common tree species (Quercus robur, Pinus sylvestris and Fagus sylvatica) collected for different ecological, management and climate purposes in the south Baltic Sea region at the border of three bioclimatic zones (temperate continental, oceanic, southern boreal). The major climate factors (temperature, precipitation, drought) affecting tree growth at monthly and seasonal scales were identified. Our analysis documents that 20th century Scots pine and deciduous species growth is generally controlled by different climate parameters, and that summer moisture availability is increasingly important for the growth of deciduous species examined. We report changes in the influence of winter climate variables over the last decades, where a decreasing influence of late winter temperature on deciduous tree growth and an increasing influence of winter temperature on Scots pine growth was found. By comparing climate-growth responses for the 1943-1972 and 1973-2002 periods and characterizing site-level growth response stability, a descriptive application of spatial segregation analysis distinguished sites with stable responses to dominant climate parameters (northeast of the study region), and sites that collectively showed unstable responses to winter climate (southeast of the study region). The findings presented here highlight the temporally unstable and nonuniform responses of tree growth to climate variability, and that there are geographical coherent regions where these changes are similar. Considering continued climate change in the future, our results provide important regional perspectives on recent broad-scale climate-growth relationships for trees across the temperate to boreal forest transition around the south Baltic Sea.

Mixed-severity fire history at a forest-grassland ecotone in west central British Columbia, Canada

This study examines spatially variable stand structure and fire-climate relationships at a low elevation forest-grassland ecotone in west central British Columbia, Canada. Fire history reconstructions were based on samples from 92 fire-scarred trees and stand demography from 27 plots collected over an area of about 7 km² . We documented historical chronologies of widespread fires and localized grassland fires between AD 1600 and 1900. Relationships between fire events, reconstructed values of the Palmer Drought Severity Index, and annual precipitation were examined using superposed epoch and bivariate event analyses. Widespread fires occurred during warm, dry years and were preceded by multiple anomalously dry, warm years. Localized fires that affected only grassland-proximal forests were more frequent than widespread fires. These localized fires showed a lagged, positive relationship with wetter conditions. The landscape pattern of forest structure provided further evidence of complex fire activity with multiple plots shown to have experienced low-, mixed-, and/or high-severity fires over the last four centuries. We concluded that this forest-grassland ecotone was characterized by fires of mixed severity, dominated by frequent, low-severity fires punctuated by widespread fires of moderate to high severity. This landscape-level variability in fire-climate relationships and patterns in forest structure has important implications for fire and grassland management in west central British Columbia and similar environments elsewhere. Forest restoration techniques such as prescribed fire and thinning are oftentimes applied at the forest-grassland ecotone on the basis that historically high frequency, low-severity fires defined the character of past fire activity. This study provides forest managers and policy makers with important information on mixed-severity fire activity at a low elevation forest-grassland ecotone, a crucial prerequisite for the effective management of these complex ecosystems.

The effect of chemotherapy on health-related quality of life in mesothelioma: results from the SWAMP trial

Background:

The effect of chemotherapy on health-related quality of life (HRQoL) in malignant pleural mesothelioma (MPM) is poorly understood. Patient-individualised prognostication and prediction of treatment response from chemotherapy is useful but little evidence exists to guide practice.

Method:

Consecutive patients with MPM who were fit for first-line chemotherapy with pemetrexed and cisplatin\carboplatin were recruited and followed up for a minimum of 12 months. This study focussed on the HRQoL outcomes of these patients using the EQ-5D, EORTC QLQ-C30 and LC13.

Results:

Seventy-three patients were recruited of which 58 received chemotherapy and 15 opted for best supportive care (BSC). Compliance with HRQoL questionnaires was 98% at baseline. The chemotherapy group maintained HRQoL compared with the BSC group whose overall HRQoL fell (P=0.006) with worsening dyspnoea and pain. The impact of chemotherapy was irrespective of histological subtype although those with non-epithelioid disease had worse HRQoL at later time points (P=0.012). Additionally, those with a falling mesothelin or improvement on modified-RECIST CT at early follow-up had a better HRQoL at 16 weeks.

Conclusions:

HRQoL was maintained following chemotherapy compared with a self-selected BSC group. Once chemotherapy is initiated, a falling mesothelin or improved RECIST CT findings infer a quality-of-life advantage.

Resonance contributions to anti-Stokes/Stokes ratios under surface enhanced Raman scattering conditions

Anti-Stokes/Stokes asymmetries under surface enhanced Raman scattering (SERS) conditions are studied for a wide variety of SERS-active media and different analytes. Evidence is provided for the existence of underlying resonances that create these asymmetries. We show here that these resonances are associated with the electromagnetic coupling between the analyte (probe) and the metal. The work demonstrates the use of the anti-Stokes/Stokes ratio as a tool to understand the hierarchy of resonances in the SERS problem, which is essential for quantification purposes.

Grazing-incidence hyperboloid-hyperboloid designs for wide-field x-ray imaging applications

The classical Wolter type I grazing-incidence x-ray telescope consists of a paraboloidal primary mirror and a confocal hyperboloidal secondary mirror. This design exhibits stigmatic imaging on-axis but suffers from coma, astigmatism, field curvature, and higher-order aberrations such as oblique spherical aberration. Wolter-Schwarzschild designs have been developed that strictly satisfy the Abbe sine condition and thus exhibit no spherical aberration or coma. However, for wide-field applications such as the solar x-ray imager (SXI), there is little merit in a design with stigmatic imaging on-axis. Instead, one needs to optimize some area-weighted-average measure of resolution over the desired operational field of view. This has traditionally been accomplished by mere despacing of the focal plane of the classical Wolter type I telescope. Here we present and evaluate in detail a family of hyperboloid-hyperboloid grazing-incidence x-ray telescope designs whose wide-field performance is much improved over that of an optimally despaced Wolter type I and even somewhat improved over that of an optimally despaced Wolter-Schwarzschild design.

Linguistic analysis to assess medically related posttraumatic stress symptoms

The authors examined the presence of posttraumatic stress symptoms (PTSS) in 20 patients requiring ventilation after acute respiratory distress. The subjects completed a semistructured interview about their ventilation experience that was subject to content and linguistic analysis. Subjects also completed two self-report measures to assess PTSS and socioemotional adjustment. Subjects who endorsed PTSS were more likely to use a narrative style suggesting emotional involvement in their recall of the stressful event. The authors indicate that the presence of PTSS is a common consequence of traumatic medical experiences and that denial of distress may be an adaptive short-term coping strategy.

Electrocyclic ring-opening/pi-allyl cation cyclization reaction sequences involving gem-dihalocyclopropanes as substrates: application to syntheses of (+/-)-, (+)-, and (-)-gamma-lycorane

The readily prepared gem-dibromocyclopropanes (+/-)-13 and (+/-)-19 each engage in a silver(I)-promoted electrocyclic ring-opening/pi-allyl cation cyclization sequence to deliver the hexahydroindole (+/-)-20, which participates in a Suzuki cross-coupling reaction with arylboronic acid 3 to give the tetracyclic compound (+/-)-21. Catalytic hydrogenation of this last compound proceeds in a completely stereoselective manner to give the saturated analogue (+/-)-24, which undergoes Bischler-Napieralski cyclization on reaction with phosphorus oxychloride. The resulting lactam (+/-)-25 is then reduced with lithium aluminum hydride to give (+/-)-gamma-lycorane [(+/-)-1]. By using (-)-menthyl-derived carbamates 27 and 28, this chemistry has been extended to the synthesis of the (+)- and (-)-modifications of the title compound.

Use of meropenem 3 g once daily for outpatient treatment of infective exacerbations of bronchiectasis

Meropenem administered as a single iv 3 g dose once every 24 h was used to treat nine ambulatory patients with infective exacerbations of bronchiectasis. Serum meropenem concentrations were measured before dosing and at 30 min after each 30 min infusion. Mean pre-dose concentrations were <0.1 mg/L and mean post-dose concentrations 93.9 +/- 29.5 mg/L (95% confidence interval (CI) 86. 2-101.6, n = 59). A pathogen was cultured from sputum in six patients and eradicated (<100 cfu/g sputum) in all but one by day 6 of therapy. Previous work on animals has shown that a bacteriostatic effect is seen with meropenem when t > MIC is greater than 20-30% of the dose interval. In these nine patients, this could be achieved and was associated with successful outcome for pathogens for which MICs are </= 0.5 mg/L. Therefore, once-a-day meropenem therapy may be a useful option for outpatient treatment for isolates for which MICs are </= 0.5 mg/L.

Diffracted radiance: a fundamental quantity in nonparaxial scalar diffraction theory

Most authors include a paraxial (small-angle) limitation in their discussion of diffracted wave fields. This paraxial limitation severely limits the conditions under which diffraction behavior is adequately described. A linear systems approach to modeling nonparaxial scalar diffraction theory is developed by normalization of the spatial variables by the wavelength of light and by recognition that the reciprocal variables in Fourier transform space are the direction cosines of the propagation vectors of the resulting angular spectrum of plane waves. It is then shown that wide-angle scalar diffraction phenomena are shift invariant with respect to changes in the incident angle only in direction cosine space. Furthermore, it is the diffracted radiance (not the intensity or the irradiance) that is shift invariant in direction cosine space. This realization greatly extends the range of parameters over which simple Fourier techniques can be used to make accurate calculations concerning wide-angle diffraction phenomena. Diffraction-grating behavior and surface-scattering effects are two diffraction phenomena that are not limited to the paraxial region and benefit greatly from this new development.

A novel and simple colorimetric method for screening Giardia intestinalis and anti-giardial activity in vitro

A new and simple colorimetric method has been developed for determining activity in vitro against Giardia intestinalis. The microtitre plate assay is based upon the nucleoside hydrolase activity released from G. intestinalis by lysis. Action of the nucleoside hydrolase on the substrate analogue, 4-nitrophenyl beta-D-ribofuranoside (NPR), gives rise to a coloured product which may be determined directly by the change in absorbance. A number of other such nucleoside analogues can be similarly used, but NPR is the preferred substrate, since it gives high enzymic activity at a relatively low substrate concentration. The IC50 values determined using this method for the known anti-giardials metronidazole, tinidazole and furazolidone were consistent with previously published values. The method is simple, does not involve radioisotopes or complex instrumentation, and thus provides a convenient method for screening potential anti-giardial agents.

Experimental verification and theory for an eight-element multiple-aperture equal-gain coherent laser receiver for laser communications

The detection and processing of laser communication signals are affected by the fading induced onto these signals by atmospheric turbulence. One method of reducing this fading is to use an array of detectors in which each of the detector outputs are added together coherently. We present experimental verification and theory of a 1.06 mum eight-element coherent receiver used to mitigate the effects of fading over a 1-km outdoor range. The carrier-to-noise ratio (CNR) was measured on a single channel and was then compared with the CNR obtained from the coherent sum of the eight channels. The increase of the mean CNR for the coherent sum as compared with a single aperture was observed proportional to the number of the apertures under different conditions of atmospheric turbulence. The measured mean CNR gain fitted the theoretical prediction well when the laser intensity fluctuations followed the gamma distribution.

Three cases of meningococcal pneumonia

Three cases of pneumonia due to Neisseria meningitidis are described. In all three cases the organism was isolated only from blood cultures, but in the presence of good clinical and radiological evidence of pneumonia. The isolates belonged to three different serogroups: B type 2b, C, and Y. The cases illustrate the fact that N meningitidis can cause pneumonia and that culture of blood plays an important part in the diagnosis. Clinically there is nothing to differentiate meningococcal pneumonia from other causes of community acquired pneumonia. Predisposing factors include aspiration, immunosuppression, influenza, and adenovirus infections. When diagnosed, pneumonia due to N meningitidis should be notified and prophylaxis given as for meningitis or septicaemia.

Precision pointing and tracking through random media by exploitation of the enhanced backscatter phenomenon

The active illumination of a target through a turbulent medium with a monostatic transmitter-receiver results in a naturally occurring conjugate wave caused by reciprocal scattering paths that experience identical phase variations. This reciprocal path-scattering phenomenon produces an enhanced backscatter in the retroverse direction (precisely along the boresight of the pointing telescope). A dual aperture causes this intensity enhancement to take the form of Young's interference fringes. Interference fringes produced by the reciprocal path-scattering phenomenon are temporally stable even in the presence of time-varying turbulence. Choosing the width-to-separation ratio of the dual apertures appropriately and utilizing orthogonal polarizations to suppress the time-varying common-path scattered radiation allow one to achieve interferometric sensitivity in pointing accuracy through a random medium or turbulent atmosphere. Computer simulations are compared with laboratory experimental data. This new precision pointing and tracking technique has potential applications in ground-to-space laser communications, laser power beaming to satellites, and theater missile defense scenarios.

Comparison of clinical evaluation and computed tomographic diagnostic accuracy for tumors of the larynx and hypopharynx

Ninety-five patients with laryngeal and hypopharyngeal cancer were examined and staged preoperatively by clinical evaluation (CE) and computed tomography (CT). The CE and CT staging were compared to each other and to the pathologic (PT) staging of the tumors. The CT staging showed high accuracy in staging transglottic (88%), supraglottic (68%), and oropharyngeal tumors invading the larynx (68%) when compared to the PT findings. The CT staging was less effective in evaluating glottic tumors (46%), both overstaging (12%) and understaging (20%) cases. Combined CE-CT evaluation showed higher accuracy in staging all tumors (84%) compared to CE alone (52%) or CT alone (68%). The findings suggest that combined CE-CT should be used to evaluate laryngeal and hypopharyngeal tumors.

Diffraction effects of telescope secondary mirror spiders on various image-quality criteria

Diffraction from secondary mirror spiders can significantly affect the image quality of optical telescopes; however, these effects vary drastically with the chosen image-quality criterion. Rigorous analytical calculations of these diffraction effects are often unwieldy, and virtually all commercially available optical design and analysis codes that have a diffraction-analysis capability are based on numerical Fourier-transform algorithms that frequently lack an adequate sampling density to model narrow spiders. The effects of spider diffraction on the Strehl ratio (or peak intensity of the diffraction image), full width at half-maximum of the point-spread function, the fractional encircled energy, and the modulation transfer function are discussed in detail. A simple empirical equation is developed that permits accurate engineering calculations of fractional encircled energy for an arbitrary obscuration ratio and spider configuration. Performance predictions are presented parametrically in an attempt to provide insight into this sometimes subtle phenomenon.

Field-of-view limitations of phased telescope arrays

The optical performance of imaging phased telescope arrays is degraded by various design, manufacturing, and operational errors. Perhaps the most basic and fundamental of these error sources are the residual aberrations of the optical design chosen for the individual telescopes. We show that third-order field curvature and distortion, which are rather benign aberrations in a conventional telescope, result in relative phase and tilt errors between the individual telescopes making up the array. The field-dependent image degradation caused by these relative phase and tilt errors is then predicted for different subaperture configurations and telescope design parameters. For phased arrays made up of simple two-mirror telescopes, distortion limits the field of view to less than 5 arcmin for small subapertures (D < 0.5 m), and field curvature limits the field of view to less than 1 arcmin for subaperture diameters greater than 2 m. Quantitative parametric results yielding tolerances for residual field curvature as the phased array is scaled up in size are presented graphically. If a 0.5-deg field of view is desired for telescope diameters greater than 2 m, complex telescope configurations are necessary to satisfy the rather tight tolerances on both field curvature and distortion.

Modeling the image quality of enhanced reflectance x-ray multilayers as a surface power spectral density filter function

Residual surface roughness over the entire range of relevant spatial frequencies must be specified and controlled in many high-performance optical systems. This is particularly true for enhanced reflectance multilayers if both high reflectance and high spatial resolution are desired. If we assume that the interfaces making up a multilayer coating are uncorrelated at high spatial frequencies (microroughness) and perfectly correlated at low spatial and midspatial frequencies, then the multilayer can be thought of as a surface power spectral density (PSD) filter function. Multilayer coatings thus behave as a low-pass spatial frequency filter acting on the substrate PSD, with the exact location and shape of this cutoff being material and process dependent. This concept allows us to apply conventional linear systems techniques to the evaluation of image quality and to the derivation of optical fabrication tolerances for applications utilizing enhanced reflectance x-ray multilayers.

Effects of surface scatter on the optical performance of x-ray synchrotron beam-line mirrors

The increased availability of advanced synchrotron radiation sources is resulting in a resurgence of activity in the field of x-ray and extreme ultraviolet imaging systems. However, scattering effects caused by residual optical fabrication errors frequently dominate geometrical design errors in the degradation of image quality at these very short wavelengths. Traditional optical design and analysis techniques (geometrical ray tracing) are therefore inadequate for predicting the performance of high-resolution synchrotron beam-line optics. A surface-scattering theory must be implemented to model the image degradation effects of residual surface irregularities over the entire range of relevant spatial frequencies. This includes small-angle scattering effects caused by mid-spatial-frequency surface errors that fall between the traditional figure and finish specifications. Performance predictions are presented parametrically to provide insight into the optical fabrication tolerances necessary to meet the requireme nts of a specific application.

Image characteristics in applications utilizing dilute subaperture arrays

When a large aperture is synthesized with an array of smaller subapertures for high-resolution imaging applications, it is important not only to arrange the subapertures to achieve minimal spatial frequency redundancy but also to choose the size of the subapertures (i.e., the dilution ratio) necessary to achieve the best possible image quality. Spurious or ghost images often occur even for nonredundant dilute subaperture arrays. We show that array configurations producing a uniform modulation transfer function will not exhibit these undesirable ghost images. A prescription that is unique and original (to the best of our knowledge) is then presented for constructing both one-dimensional and two-dimensional configurations of dilute subaperture arrays that results in a uniform spatial frequency response with an arbitrarily high spatial resolution for reciprocal path-imaging applications.

Demonstration of supernumerary tracheal bronchus by computed tomographic scanning and magnetic resonance imaging

A bronchus arising directly from the trachea is an infrequent congenital anomaly which usually represents the displaced origin of a normal bronchus. Rarely, a true supernumerary tracheal bronchus occurs supplying an associated tracheal lobe. The case is described of a patient in whom a supernumerary tracheal bronchus and tracheal lobe was demonstrated by computed tomographic scanning and magnetic resonance imaging.

Average speckle size as a function of intensity threshold level: comparisonof experimental measurements with theory

Speckle phenomena result whenever spatially coherent radiation is reflected from a rough surface or propagated through a random medium such as atmospheric turbulence. Speckle characteristics are therefore a major concern in many laser-imaging or wave-propagation applications. We present the results of experimental measurements of target-induced speckle patterns produced in the laboratory from a variety of targets and illumination conditions. We then compare these experimental measurements with a theoretical model for the average speckle size as a function of intensity threshold level. Excellent agreement is obtained for intensity threshold levels greater than approximately twice the mean intensity level.

Prediction of occult neck disease in laryngeal cancer by means of a logistic regression statistical model

The ability to accurately predict the presence of subclinical metastatic neck disease in clinically N0 patients with primary epidermoid cancer of the larynx would be of great value in determining whether to perform an elective neck dissection. We describe a statistical approach to estimating the probability of occult neck disease given pretreatment clinical parameters. A retrospective study was performed involving 736 clinically N0 patients with primary laryngeal cancer who were treated surgically with primary resection and ipsilateral neck dissection. Nodal involvement was determined histologically after surgical lymphadenectomy. A logistic regression model was used to derive an equation that calculated the probability of occult neck metastasis based on pretreatment T stage, tumor location, and histologic grade. The model has a sensitivity of 74%, a specificity of 87%, and can be entered into a programmable calculator.

Mycobacterial contamination of fibreoptic bronchoscopes

Contamination of bronchoalveolar lavage specimens by environmental mycobacteria in hospital water supplies may lead to diagnostic confusion, particularly in immunocompromised patients. Mycobacteria may become concentrated in the tubing of bronchoscope disinfecting machines. It is very difficult to eradicate these organisms once contamination has occurred.

Guidelines for the management of spontaneous pneumothorax. Standards of Care Committee, British Thoracic Society

Simple flow diagrams, with explanatory notes, have been devised to assist in the immediate and subsequent management of patients presenting to casualty departments with spontaneous pneumothorax. They cover decision making about which patients require admission; whether a drainage procedure is necessary; if so, the appropriate method, including technical details; inpatient treatment; referral of inpatients to a respiratory specialist; and follow up arrangements. The guidelines, designed for incorporation into casualty and ward handbooks, have already proved valuable in several district general hospitals, and can be used as a basis for audit.

Epidermoid carcinoma of the oral cavity and oropharynx: validity of the current AJCC staging system and new statistical tools for the prediction of subclinical neck disease

The 1983 and 1988 AJCC T- and N-staging systems were compared using the case records of 531 patients with primary epidermoid malignancies of the oral cavity. All patients had a minimum followup of 5 years. There were 390 patients with early stage (T1, T2) disease and 141 with advanced stage (T3, T4) lesions according to both the 1983 and 1988 T-definitions: 342 patients manifested no clinical nodes (NO), 189 had clinically evident nodes (N1-N3), and none had metastatic disease. Cox regression analysis demonstrated that the 1983/1988 T-stage definitions differentiated survival successfully (p < 0.001). The 1988 staging system for nodal disease showed a highly significant separation of N2 and N3 when compared with the 1983 system (p < 0.001). Of the 342 patients who were staged N0, 154 had primary neck dissection. Logistic regression predicted the incidence of subclinical disease according to the site and the T-stage of the primary tumor with a sensitivity of 78% and a specificity of 95%. We conclude that the 1988 N-stage definition is a better prognosticator of survival than the 1983 definition. Furthermore, a logistic regression model can be used to predict the probability of subclinical disease in primary oral cavity cancers.

Clinical staging for primary malignancies of the supraglottic larynx

A study of 520 patients with primary supraglottic cancer was conducted. The tumors were staged according to the 1983 and 1988 American Joint Committee on Cancer (AJCC) T- and N-stage definitions. There were 293 patients with early stage (T1, T2) tumors, 227 with advanced stage (T3, T4) tumors and 428 with early nodal disease (N0, N1) in both systems. In the 1983 N-staging, there were 44 N2 and 48 N3 lesions; in the 1988 N-staging, there were 62 N2 and 30 N3 lesions. Cox regression analysis showed that the 1983 and 1988 T-stage (T1 through T4) definitions successfully prognosticate for survival when patients were without neck node involvement. In contrast, when neck nodes were present, the N-stage (N0 through N3) of the disease prognosticated survival better than T-stage. Further analyses showed that the 1988 N-stage definition provided a better separation between N2 and N3 lesions compared to the 1983 version. Combined-modality treatment (surgery and radiation) significantly improved survival compared to single-modality treatment (surgery or radiation alone) when patients were staged T4 and N0 through N3 neck disease, but not when patients advanced from T1 to T3. Comparison of treatment efficacy over the last four decades for single- and combined-modality treatment did not reveal statistically significant differences in survival rates in our patient population. This was consistent with cumulative results of various institutions over the last four decades. We conclude that the 1988 AJCC T- and N-stage definitions successfully prognosticate for T-stage (T1 through T4) and N-stage (N0 through N3) with better separation of N2 and N3 lesions compared to the 1983 version.

Angular grating anomalies: effects of finite beam size on wide-angle diffraction phenomena

Diffraction gratings are known to exhibit anomalous behavior at certain critical wavelengths or incident angles. These traditional anomalies manifest themselves as abrupt variations in diffracted order efficiency or grating absorption, while their angular position remains unchanged as predicted by the grating equation. Experimental observations have been reported, indicating a diffraction grating anomaly in the angular position of certain diffracted orders that appears to violate the grating equation. Several exotic physical mechanisms have been suggested as possible causes of this intriguing behavior; however, in this paper we show that this angular grating anomaly is the straightforward result of finite beam size on wide-angle diffraction phenomena, as described by simple scalar diffraction theory.

The effects of carbamazepine on stuttering

No pharmacological treatment protocol has proven generally useful for all patients who stutter. Various medications, behavior therapy, relaxation, suggestion, and social-based therapies have been used. For this drug treatment study, two groups of adult stutterers were followed in an 8-week open label protocol. All subjects had in the past received speech therapy; none had been treated previously with medication for stuttering. The first group (N = 12) received a maximum dose of 800 mg of carbamazepine; the second group (N = 8) received a maximum dose of 400 mg of carbamazepine. Each patient served as his or her own control. A series of systematic speech tests was given weekly to determine the variability of fluency for each subject. A statistically significant change occurred for a number of "expectancy to stutter" characteristics. Subjects felt that they stuttered less often while taking carbamazepine. Subjective effects began before medication and continued after patients discontinued the medication. Struggle characteristics also subjectively decreased. However, no objective improvement was found. No change was found in percentage of words stuttered, reading improvement, or improvement in spontaneous speech rate. Interrater reliability showed a correlation of .996. Three carbamazepine serum level therapeutic windows were inspected with negative results. Interestingly, naive listener ratings did show a statistically significant improvement on carbamazepine versus placebo. Future anecdotal reports of pharmacological improvement of stuttering should be subjected to rigorous objective testing before general acceptance.

Surgical pathology of cancer of the oral cavity and oropharynx

A study was designed to determine the influence of certain surgical pathologic findings on tumor spread and survival in patients with cancer of the oral cavity and oropharynx. All patients with the histopathological diagnosis of carcinoma of the oral cavity or oropharynx from 1955 to 1983 were included in the study. Using the Head and Neck Tumor Registry of the department of otolaryngology of the Washington University School of Medicine, information was obtained regarding preoperative evaluation, staging, classification, diagnosis, treatment, surgical pathology parameters, and outcome results. The patient populations consisted of 545 patients with oral cavity cancer and 224 patients with oropharynx cancer, all of whom were eligible for 3-year follow-up. Information from a retrospective analysis of the pretreatment examination records regarding site and size of the primary tumor and neck dissection, and specific treatment, and from surgical pathology reports regarding site, size, tumor spread and resection margins, was correlated with treatment outcome. The database file was analyzed using dbase III and its companion program Framework, and SAS PC (Statistical Analysis Systems for personal computers).

Diffraction effects in grazing incidence x-ray telescopes

There is increasing interest worldwide in the use of tightly nested grazing incidence imaging mirrors for high-throughput x-ray telescopes. Diffraction effects of x-ray optical systems are often (justifiably) ignored due to the small wavelength of the x-ray radiation. However, the extremely large obscuration ratio inherent to grazing incidence optical systems produces profound degradation of the diffraction image over that produced by a moderately obscured aperture of the same diameter. Although many of the intended applications are moderate-resolution spectroscopic instruments, there is always a desire for high-resolution imaging as well. In this paper we show that diffraction effects can dominate other potential error sources at the low-energy (long-wavelength) end of the intended operating spectral range of some existing or planned x-ray telescopes. Parametric performance predictions are presented and compared with x-ray astronomy performance goals.

Clinical classification and staging for primary malignancies of the maxillary antrum

A study of 51 patients with primary malignant maxillary sinus neoplasms was conducted. None of the patients had neck nodes and/or metastases, and each had 5-year follow-up. The tumors were staged according to the 1983 and 1988 American Joint Committee on Cancer staging systems for maxillary sinus cancers. There were 13 early stage (T1, T2) and 38 advanced (T3, T4) tumors in both systems. Cox regression analyses of survival curves showed increasingly worse prognoses for advanced tumors in both T-staging systems. Further analyses showed a significant difference in survival between T3 and T4 in the 1988, but not in the 1983 system. There were no significant differences in survival according to treatment modality or histological type of malignancy. We conclude that the 1988 system prognosticates successfully for T-stage (1 to 4) and demonstrates significant improvement in detecting T3 versus T4 differences compared to the 1983 system. The 1988 system applies equally for epidermoid cancer and other malignancies of the antrum.

The pharmacokinetics and sputum penetration of ampicillin and amoxycillin following simultaneous i.v. administration

Five patients with exacerbation of chronic bronchitis received as a single iv injection 500 mg of ampicillin and 500 mg of amoxycillin. Blood and sputum samples were collected at timed intervals following dosing and the concentrations of the two antibiotics present in the samples were determined by HPLC analysis. No statistically significant differences were observed between the serum concentrations of ampicillin and amoxycillin, and the pharmacokinetics of the two drugs were almost identical, with half lives of 93 min (amoxycillin) and 103 min (ampicillin). Sputum amoxycillin concentrations were significantly higher (Student's paired t-test; P less than 0.001) than those of ampicillin, with mean levels two hours after dosing of 2.9 mg/l (range 1.9-4.0) for amoxycillin and 1.4 mg/l (range 0.8-2.4) for ampicillin.

Natural history of treated T1N0 squamous carcinoma of the glottis

The records of 373 patients with T1N0 squamous carcinoma of the glottis were examined. Of these, 271 underwent initial hemilaryngectomy; 102 had full-course irradiation for cure. While the overall survival rates of the two initial therapies were similar, failure of the initial treatment modality was approximately twice as frequent in the irradiated patients (34.4%) as in the patients undergoing hemilaryngectomy (16.9%). The effect of this difference in initial failure rate on quality of life and on cost of overall therapy will be discussed.

Transfer function characterization of grazing incidence optical systems

By using Fourier techniques and linear systems theory we have derived an analytic expression for a generalized transfer function for grazing incidence optical systems operating at ultraviolet and x-ray wavelengths that includes the effects of optical fabrication errors over the entire range of relevant spatial frequencies. The Fourier transform of this transfer function yields the image distribution (or point spread function) from which encircled energy characteristics or other image quality criteria can be obtained. This transfer function characterization of grazing incidence optical systems allows parametric trade studies and sensitivity analyses to be performed as well as the derivation of fabrication tolerances necessary to satisfy a given image quality requirement.

Ghost image behavior in Wolter type 1 x-ray telescopes

In Wolter type I grazing incidence telescopes, ghost images result whenever unreflected xrays or singly reflected x rays pass through the telescope and impinge on the focal plane. These ghost images degrade imagequality and can bo eliminated by appropriately positioned stops and baffles. However, conflicting demandsbe placed on an aperture design by requirements for field of view, vignetting, and ghost image control. These problems are particularly severe for high energy x-ray telescopes which require very small grazing angles of incidence. We have developed and used analytical and numerical tools to perform parametric analyses of ghost image behavior and to obtain an aperture plate design capability that can, be utilized to satisfy specific ghost image requirements.

Subunit influenza vaccination in adults with asthma: effect on clinical state, airway reactivity, and antibody response

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Defense style and the perception of asthma

Approximately 15% of patients with bronchial asthma are unable to sense marked changes in airway obstruction. We have investigated the hypothesis that inability to sense changes in the severity of bronchial asthma varies with insensitivity to emotional arousal, which in turn is associated with repressive defense styles. Nine asthmatic patients were studied comparing actual changes in peak flow rate using a coded peak flow meter and in arousal during a stress-inducing psycholinguistic protocol with perceived changes. Our hypotheses were confirmed. Ability to perceive changes in asthma could be predicted from performance on the psycholinguistic stress test (Spearman's rho = +0.733, p less than 0.01). Repressors performed significantly worse on the asthma perception task (Spearman's rho = -0.650, p less than 0.05). The results suggest a role for defense pathology in the psychomaintenance of asthma.