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The concentrations of trace metals in sewage water and sludge samples from River Kubanni drainage basin in Zaria City, Nigeria were investigated in this study. The drainage basin is utilized as a source for irrigation water, during dry seasons. The sewage water quality characteristics in three month sampling periods, that is, February - April, 2008 (peak of dry season and period of intensive usage of the sewage water), the speciation of metals in the sewage sludge from the drainage basin, and the risk to sewage water column contamination were evaluated. The sewage water quality characteristics were mostly beyond the recommended irrigation water standards by the food and agriculture organization (FAO) and United State environmental protection agency (USEPA) except for zinc and nickel. In addition, the average values of Cd, Cu, Pb, Cl - and NO 3 - in sewage water samples analyzed were higher than the respective reference values for irrigation water. To study the speciation of metals in sewage sludge, five metals (Zn, Ni, Cu, Pb and Cd) in the sludge were subjected to sequential extractions. The metals analyzed were distributed in both the non-residual and residual phases. Total extractable trace metals in sewage sludge were: Zn (403.3 mg/kg dry weight), Ni (184.2 mg/kg dry weight), Cu (303.4 mg/kg dry weight), Pb (129.0 mg/kg dry weight) and Cd (19.7 mg/kg dry weight). However, there was low risk to sewage water contamination based on the calculated individual contamination factors (ICF) obtained for sewage sludge from the trace metal sequential extractions. From the calculated individual contamination factors, Ni and Zn followed by Cd and Pb posed the highest risk to sewage water contamination. Based on this study, the human health is at risk, since sewage water from the drainage basin has been the source for irrigation water during dry seasons, which might lead to trace metal ingestion by soil and subsequently by vegetables. Thus, this might become important pathways of human exposure to metal contamination. Key words: Trace metals, speciation, contamination factor, sewage water and sludge.

A new modulation technique for Continuous Wave (CW) Lidar is presented based on Binary Phase Shift Keying (BPSK) using orthogonal carriers closely spaced in frequency, modulated by Maximum Length (ML) sequences, which have a theoretical autocorrelation function with no sidelobes. This makes it possible to conduct multi-channel atmospheric differential absorption measurements in the presence of thin clouds without the need for further processing to remove errors caused by sidelobe interference while sharing the same modulation bandwidth. Flight tests were performed and data were collected using both BPSK and linear swept frequency modulation. This research shows there is minimal or no sidelobe interference in the presence of thin clouds for BPSK compared to linear swept frequency with significant sidelobe levels. Comparisons between of CO(2) optical depth Signal to Noise (SNR) between the BPSK and linear swept frequency cases indicate a 21% drop in SNR for BPSK experimentally using the instrument under consideration.

An interpolation method is described for range measurements of high precision altimetry with repeating intensity modulated continuous wave (IM-CW) lidar waveforms using binary phase shift keying (BPSK), where the range profile is determined by means of a cross-correlation between the digital form of the transmitted signal and the digitized return signal collected by the lidar receiver. This method uses reordering of the array elements in the frequency domain to convert a repeating synthetic pulse signal to single highly interpolated pulse. This is then enhanced further using Richardson–Lucy deconvolution to greatly enhance the resolution of the pulse. We show the sampling resolution and pulse width can be enhanced by about two orders of magnitude using the signal processing algorithms presented, thus breaking the fundamental resolution limit for BPSK modulation of a particular bandwidth and bit rate. We demonstrate the usefulness of this technique for determining cloud and tree canopy thicknesses far beyond this fundamental limit in a lidar not designed for this purpose.

An interpolation method is described for range measurements of high precision and altimetry using repeating intensity-modulated continuous wave (IM-CW) lidar waveforms, where the range is determined by means of a cross-correlation between the digital form of the transmitted signal and the digitized return signal collected by the lidar receiver. This method uses reordering of the array elements in the frequency domain to convert a repeating synthetic pulse signal to single highly interpolated pulse. The computation of this processing is marginally greater than the correlation itself, as it only involves reordering of the correlation in the frequency domain, which makes it possible to implement this in a real time application. It is shown through theoretical arguments and flight-testing that this is a viable method for high-speed interpolated range measurements. Standard deviation is 0.75 m over water with only 350 mw of transmitted power at 2600 m.

Optical QND measurements may be made using devices which act as nonlinear beam splitters, transmitting noise in a phase-sensitive way. One class of such devices are resonant optical cavities containing a nonlinear medium. By appropriate choice of nonlinearity and operating parameters, various QND observables may be measured. We consider, in particular, the extent to which the QND performance of these devices is degraded by intracavity losses.

The 2007 National Research Council (NRC) Decadal Survey on Earth Science and Applications from Space recommended Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) as a mid-term, Tier II, NASA space mission. ITT Exelis, formerly ITT Corp., and NASA Langley Research Center have been working together since 2004 to develop and demonstrate a prototype Laser Absorption Spectrometer for making high-precision, column CO2 mixing ratio measurements needed for the ASCENDS mission. This instrument, called the Multifunctional Fiber Laser Lidar (MFLL), operates in an intensity-modulated, continuous-wave mode in the 1.57- micron CO2 absorption band. Flight experiments have been conducted with the MFLL on a Lear-25, UC-12, and DC-8 aircraft over a variety of different surfaces and under a wide range of atmospheric conditions. Very high-precision CO2 column measurements resulting from high signal-to-noise (great than 1300) column optical depth measurements for a 10-s (approximately 1 km) averaging interval have been achieved. In situ measurements of atmospheric CO2 profiles were used to derive the expected CO2 column values, and when compared to the MFLL measurements over desert and vegetated surfaces, the MFLL measurements were found to agree with the in situ-derived CO2 columns to within an average of 0.17% or approximately 0.65 ppmv with a standard deviation of 0.44% or approximately 1.7 ppmv. Initial results demonstrating ranging capability using a swept modulation technique are also presented.

All clinical classifications for laryngeal cancer are compromises based on clinical and imaging evaluations, with no concern for important elements such as phenotype, host-tumor relationship, and any concomitant nonneoplastic disease. The various staging systems are critically examined along with a report on the outcome of an international survey on the applicability of the TNM system in relation to laryngeal neoplasms, promoted by The Laryngeal Cancer Association.

The onset of period-doubling behaviour in cardiac physiology is often associated with pathological states and an adverse prognosis. Changes in myocardial loading frequently accompany cardiac disease, and there is growing evidence that they may be important in the genesis of cardiac arrhythmias. This study investigates the effect of changes in myocardial loading on period-doubling bifurcations of mechanical activity in the heart of the anaesthetized pig. Changes in loading can both produce and abolish period-doubling bifurcations in the mechanical behaviour of the heart. The dual effect of changes in loading may reflect the movement of the system around a bifurcation point.

1. The factors leading to the alternation in myocardial contractility believed primarily responsible for pulsus alternans are not known. We examine regional and global contraction patterns in the in situ heart at stimulation rates just below the threshold for pulsus alternans to determine if events occurring in the transition to alternans can give clues to cellular mechanisms. 2. Twelve pigs were anaesthetized, the chest wall removed and regional contraction measured in three areas of the left ventricle using tripodal strain gauges. We analysed regional and global dynamics during right atrial pacing at cycle lengths 50-150 ms greater than the threshold for pulsus alternans. 3. At pacing cycle lengths 50 ms greater than that required to produce pulsus alternans seven of twelve pigs showed alternans in the maximum rate of ventricular pressure decay but none showed alternans in the maximum rate of pressure rise. Pigs showing alternans in global relaxation were more likely to show alternans in regional contracility (P < 0.05). 4. Twenty-six of the thirty-six areas sampled showed alternans in end-diastolic length at pacing rates below the threshold for pulsus alternans. In fifteen of these areas alternation in end-diastolic length occurred in the absence of alternans in measures of contractility. 5. Alternans in global measures of relaxation may simply be a manifestation of regional alternans in contractility. It is therefore not appropriate, from global haemodynamic data, to suppose that alternans in relaxation is the primary abnormality in the generation of pulsus alternans.(ABSTRACT TRUNCATED AT 250 WORDS)

Objective: The electrophysiological events accompanying early ischaemia are important. The aim of this study was to investigate mechano-electric feedback in acute regional myocardial ischaemia in the intact heart in situ by measuring the change in action potential duration in response to increased ventricular loading imposed by transient aortic occlusion. Methods: 11 landrace pigs were anaesthetised and their hearts exposed. A pneumatically operated blood pressure clamp was placed around the aorta. Monophasic action potentials and an index of segment motion were recorded from the epicardium in and around the ischaemic area produced by a snare placed around a coronary artery. Ventricular and systemic arterial pressures were measured. An initial aortic clamp was performed during which control recordings were taken. The coronary artery was then tied and the aorta clamped for 5-10 s every 5 min for the duration of the 30 min tie. Recordings were taken from the ischaemic area and non-ischaemic areas. Results: Aortic clamp before ischaemia increased intraventricular diastolic and systolic pressure and reduced action potential duration in all the areas studied (p< 0.001). During acute regional myocardial ischaemia aortic clamping resulted in significantly more shortening of the action potential in the ischaemic area after 10 min of ischaemia than in the control area (5 ms v 10 ms, p = 0.008). Over the following 20 min the degree of shortening decreased. The greater shortening at 10 min could not be attributed to changes in the end diastolic segment length or peak ventricular pressure and could thus represent a change in the expression of mechano-electric feedback by ischaemic myocardium rather than a change in loading conditions. Conclusions: During the first 30 min following a coronary artery occlusion mechano-electric feedback in the ischaemic myocardium varies with time. Cardiovascular Research 1994:; 28 :528-534

Objective: The aim was to investigate the behaviour of regional myocardium during mechanical alternans in a multidirectional manner. Methods: Mechanical alternans was induced in 12 anaesthetised open chested pigs by rapid atrial pacing. In contrast to previous studies, regional mechanical activity was simultaneously assessed at up to three different sites on the left ventricle using epicardial measuring devices able to provide multidirectional information on segment motion. Pressure-length loops were plotted to assess different patterns of segmental motion. The integral of pressure and length was calculated to obtain a regional work index for each beat. Results: Pressure-length loops revealed profound abnormalities in segment motion and work index during regional mechanical alternans. Myocardial segments either performed alternate amounts of positive work on each beat or alternate amounts of positive and negative work on each beat. Alternating segments contracted out of phase with each other and were occasionally stretched during systole. Conclusions: The spatio-temporal heterogeneity of regional mechanical behaviour is greatly increased during mechanical alternans. Cardiovascular Research 1993; 27 :1639-1644

One hundred and four larynges removed from infants registered as dying fromSudden Infant Death Syndrome (SIDS) and 20 control larynges from infants of matching ages, were examined histologically. Excessive amounts of subglottic submucosal glandular tissue had reduced the available airway by more than half in 35 per cent of the SIDS larynges within the age group two to four months. In 30 per cent of this group the airway reduction was more than 60 per cent. It is suggested that hyperplasia of subglottic mucous glands is one cause of fatal hypoxia in sudden unexpected infant death.

Mechanically stabilized earth (MSE) walls are frequently constructed to accommodate widening of existing roads or construction of new roadways in steep terrain. Because substantial excavation must be performed to establish a flat bench upon which to construct the MSE wall, unshored construction may not be feasible. Therefore, a shoring wall is often constructed to stabilize the backslope to facilitate MSE wall construction. Full-scale testing was conducted to examine two hypotheses with regard to shored mechanically stabilized earth (SMSE) walls: (1) construction of an MSE wall in front of a rigid backslope (i.e., shoring system) results in reduced external lateral loading on the MSE wall compared to a conventional MSE wall; and (2) full connection of the MSE reinforcements to the shoring wall provides limited benefit. The full-scale test model was constructed using short geosynthetic reinforcements, ranging in length from 25 to 39 percent of the wall height. The test model was equipped with strain gages, pressure cells (horizontal and vertical), linear variable displacement transducers (LVDT), potentiometers, and inclinometers, as well as surveyed using optical methods. The test wall was extremely stable, even under unrealistically high footing surcharge loads, i.e. 10 times the normal traffic loading. Interpretation of the instrumentation data yielded significant results regarding potential arching effects, internal wall pressures, and reinforcement strains.

Mechanically stabilized earth (MSE) walls are often constructed to accommodate widening of existing roads or construction of new roadways. In steep terrain, substantial excavation must be performed to establish a flat bench upon which to construct the wall, and unshored construction may not be practical, particularly if room for traffic must be maintained during construction. Soil nail walls are often constructed to stabilize the backslope excavation with an MSE wall being designed and constructed in front of it. Where the two wall types are used together, termed a shored mechanically stabilized earth (SMSE) wall system, a design procedure has been developed by the Central Federal Lands Highway Division (CFLHD) of the Federal Highway Administration (FHWA) that considers both the stabilizing effect of the shoring wall with regard to reduction of lateral loads acting on the MSE wall mass as well as contributions to global stability. Existing public sector guidelines for MSE wall design suggest a minimum MSE reinforcement length equivalent to seventy percent of the design height of the MSE wall (i.e., 0.7H). However, if permanent shoring is included, a minimum SMSE reinforcement length equivalent to 30 percent of the wall height (0.3H) is recommended. This paper, written as a summary of the CFLHD design guidelines, discusses the evolution of MSE walls through the development of this innovative type of wall construction and provides guidance on when SMSE wall construction may be viable.

The current Earth observing capability depends primarily on spacecraft missions and ground-based networks to providethe critical on-going observations necessary for improved understanding of the Earth system. Aircraft missions play animportant role in process studies but are limited to relatively short-duration flights. Suborbital observations havecontributed to global environmental knowledge by providing in-depth, high-resolution observations that space-based andin-situ systems are challenged to provide; however, the limitations of aerial platforms - e.g. , limited observing envelope,restrictions associated with crew safety and high cost of operations have restricted the suborbital program to a supportingrole. For over a decade, it has been recognized that autonomous aerial observations could potentially be important.Advances in several technologies now enable autonomous aerial observation systems (AAOS) that can providefundamentally new observational capability for Earth science and applications and thus lead scientists and engineers torethink how suborbital assets can best contribute to Earth system science. Properly developed and integrated, thesetechnologies will enable new Earth science and operational mission scenarios with long term persistence, higher-spatialand higher-temporal resolution at lower cost than space or ground based approaches. This paper presents the results of ascience driven, systems oriented study of broad Earth science measurement needs. These needs identify aerial missionscenarios that complement and extend the current Earth Observing System. These aerial missions are analogous to spacemissions in their complexity and potential for providing significant data sets for Earth scientists. Mission classes areidentified and presented based on science driven measurement needs in atmospheric, ocean and land studies. Alsopresented is a nominal concept of operations for an AAOS: an innovative set of suborbital assets that complements andaugments current and planned space-based observing systems.Keywords: remote sensing, UAV, earth science, earth observing system, suborbital, autonomous aerial observationsystem, airborne measurements, space measurements

A novel controller, the naturally-transitioning rate-to-force controller (NTRFC), is presented for remote telerobotic systems. The controller involves shared control with a resolved-rate algorithm running concomitantly with a force accommodation algorithm, for all Cartesian axes. When the manipulator motion is unconstrained, it performs like a rate controller, where the hand controller displacement is proportional to the manipulator rate. When the manipulator contacts the environment, the control naturally transitions to a force controller, where the hand controller displacement is proportional to the manipulator force exerted. The force accommodation enables stable equilibrium in contact, with suitable gains. The transition requires no controller change and is thus termed natural. If a force reflecting hand controller is used in conjunction with the NTRFC, the force of the operator's hand is proportional to the manipulator force exerted. The NTRFC has been shown to possess excellent control characteristics for simulated Space tasks in the laboratory.

A control architecture is presented for real-time, sensor-based, shared control of remote, multiple-manipulator telerobotic systems. The system allows teleoperation, autonomy, or a combination (shared, telerobotic control). The rate-based system accepts control inputs from a variety of sources (joystick position or velocity, automated path planner position or velocity, machine vision, force/moment) simultaneously for all Cartesian axes. The system has been experimentally implemented and has proven effective in laboratory simulations of remote space tasks.

The focus of this study is to model and validate the performance of intensity-modulated continuous-wave (IM-CW) CO(2) laser absorption spectrometer (LAS) systems and their CO(2) column measurements from airborne and satellite platforms. The model accounts for all fundamental physics of the instruments and their related CO(2) measurement environments, and the modeling results are presented statistically from simulation ensembles that include noise sources and uncertainties related to the LAS instruments and the measurement environments. The characteristics of simulated LAS systems are based on existing technologies and their implementation in existing systems. The modeled instruments are specifically assumed to be IM-CW LAS systems such as the Exelis' airborne multifunctional fiber laser lidar (MFLL) operating in the 1.57 μm CO(2) absorption band. Atmospheric effects due to variations in CO(2), solar radiation, and thin clouds, are also included in the model. Model results are shown to agree well with LAS atmospheric CO(2) measurement performance. For example, the relative bias errors of both MFLL simulated and measured CO(2) differential optical depths were found to agree to within a few tenths of a percent when compared to the in situ observations from the flight of 3 August 2011 over Railroad Valley (RRV), Nevada, during the summer 2011 flight campaign. In addition, the horizontal variations in the model CO(2) differential optical depths were also found to be consistent with those from MFLL measurements. In general, the modeled and measured signal-to-noise ratios (SNRs) of the CO(2) column differential optical depths (τd) agreed to within about 30%. Model simulations of a spaceborne IM-CW LAS system in a 390 km dawn/dusk orbit for CO(2) column measurements showed that with a total of 42 W of transmitted power for one offline and two different sideline channels (placed at different locations on the side of the CO(2) absorption line), the accuracy of the τd measurements for surfaces similar to the playa of RRV, Nevada, will be better than 0.1% for 10 s averages. For other types of surfaces such as low-reflectivity snow and ice surfaces, the precision and bias errors will be within 0.23% and 0.1%, respectively. Including thin clouds with optical depths up to 1, the SNR of the τd measurements with 0.1 s integration period for surfaces similar to the playa of RRV, Nevada, will be greater than 94 and 65 for sideline positions placed +3 and +10 pm, respectively, from the CO(2) line center at 1571.112 nm. The CO(2) column bias errors introduced by the thin clouds are ≤0.1% for cloud optical depth ≤0.4, but they could reach ∼0.5% for more optically thick clouds with optical depths up to 1. When the cloud and surface altitudes and scattering amplitudes are obtained from matched filter analysis, the cloud bias errors can be further reduced. These results indicate that the IM-CW LAS instrument approach when implemented in a dawn/dusk orbit can make accurate CO(2) column measurements from space with preferential weighting across the mid to lower troposphere in support of a future ASCENDS mission.

Objectives In type 2 diabetes (T2DM), low dose Aspirin has been established for secondary cardiovascular prevention, but as yet there is no definitive data showing primary cardiovascular prevention. We hypothesized that a double dose of ASA would further reduce platelet reactivity and, given the increased platelet turnover, may be most effective when given in divided doses twice-daily. Methods This 3-period, 3-treatment, crossover study randomized 24 adults (51 ± 7 years old, BMI 31.4 ± 7.2 kg/m2, HbA1c 47 ± 7 mmol/mol) with T2DM and no prior cardiovascular disease to 2-week treatment periods with single (100 mg once-daily), double (200 mg once-daily) or split (100 mg twice-daily) ASA doses, with intervening 2 week washout periods. A generalized linear mixed model with random subject effect was used to estimate the dose response of platelet reactivity using Verify Now ASA™ as the primary outcome. Results ASA at all doses significantly reduced platelet reactivity measured by all platelet function tests except PFA-100 CADP. Verify Now ASA™ was decreased significantly from baseline 650.0 ± 19.4 aspirin reaction units (ARU) to 447.6 ± 68.1 ARU with single dose (p Conclusions ASA 100 mg given twice-daily was numerically the most effective regimen for reducing platelet reactivity as measured by platelet function tests, but future clinical outcome trials are required to confirm whether ASA 100 mg twice-daily will reduce the risk of primary cardiovascular events in patients with T2DM. Clinical Trial Registration: 2011-003123-35 (need to list URL for EUDRACT website)

Background Heart rate variability is an important prognostic indicator for sudden death. An increased risk of sudden death and arrhythmia is associated with reduced heart rate variability in heart failure. In heart failure, there is also dilatation of the atria, which raises the prospect that there could be some physiological basis to possibly link heart rate variability with atrial dilatation. We therefore investigated whether sustained atrial stretch could modulate heart rate variability directly. Methods and Results Pigs were anesthetized and their hearts exposed. A specially built device stretched the sinoatrial node before and after vagal section and then after administration of propranolol. Stretch of the sinoatrial node decreases heart rate variability in the following ways: The standard deviation of the beat-to-beat interval decreases (4.2 to 2.6 ms; P =.004), and the high-frequency components are reduced (control, 6.5±2.2 ms 2 ; during stretch, 1.4±0.3 ms 2 ; P =.003). After section of both vagi, the high-frequency components are reduced by stretch of the sinoatrial node (2.8±0.9 ms 2 for control versus 1.2±0.3 ms 2 during stretch; P =.05). Similarly, after both vagal section and β-blockade, stretch of the sinoatrial node reduces the high-frequency components (10.6±3.5 ms 2 for control versus 3.0±1.5 ms 2 during stretch; P =.01). Conclusions We conclude that stretch of the sinoatrial node reduces high-frequency heart rate variability. This may account in part for the reduced heart rate variability seen in clinical conditions in which the right atrium is dilated, such as congestive cardiac failure.

To date a large fraction of research on wind turbine sound has been directed at the audible spectrum. Rotation of wind turbine blades is a primary cause of the cyclic broad‐band sound that is characteristic of wind turbines. Auto‐correlations of measured wind turbine sounds exhibit distinct, periodic “low frequency” pulses. The pulse duration is but a fraction of the blade passage period, with energy content of the order of 20–40% of the overall mean square pressure. Analytical decomposition of the low‐frequency pulses reveals line spectra whose components diminish relatively slowly. The spectrum levels of the frequency components above 20 Hz are sufficiently high to be audible under favorable ambient conditions. This hypothesis was tested by generating and listening to various possible pressure time histories that share the shape of the low‐frequency pulses as measured by auto‐correlations. When propagation effects such as scattering are accounted for, the relative phase shifts suffered by the higher fre...

To increase quantified information about the effectiveness and subjective workload of force information relayed through manipulator input control devices, a space related task was performed by eight subjects with kinesthetic force feedback and/or local force accommodation through three different input control devices (i.e., hand controllers) operating in rate control mode. Task completion time, manipulator work, and subjective responses were measured. Results indicated a difference among the hand controllers. For the Honeywell six degree-of-freedom hand controller, the overall task completion times were shortest, the amount of work exerted was the least, and was the most preferred by test subjects. Neither force accommodation with or without reflection resulted in shorter task completion times or reduced work although those conditions were better than no force information for some aspects. Comparisons of results from previous studies are discussed.

Seventy-four larynges removed at death from children who died of sudden infant death syndrome (SIDS) have been studied by serial sectioning in the transverse plane. An increase in subepithelial glandular tissue is seen in many specimens, and the reduction in the available subglottic area has been measured with the Measuremouse Image Intensifying system. This preliminary report confirms that in some of these children with SIDS, particularly around the age of 3 months, there is a potentially lethal reduction in subglottic airway secondary to an increase in mucus-secreting glands, possibly from an associated mild upper respiratory tract infection. Accepting that adequate control infants within this age group who have not had any trauma to the laryngotracheal area are not available, these findings offer a possible explanation for what are always tragic events.

Despite possession of a well developed larynx and a gregarious nature, the Giraffe is able to utter only low moans or bleats. Morphological and histological examination, together with measurements of trachea and subglottic area, on three fresh larynges (Giraffa camelopardalis) has made it possible to explain the lack of vocal power. Factors such as thoracic expiratory flow rate, length of trachea and recurrent laryngeal nerves, together with morphological details of vocal folds, and intrinsic laryngeal muscles have all been considered, providing a unique example of the relationship between morphology and function in the mammalial larynx.

A large number of non-human mammalian larynges have been studied in an attempt to relate body mass to maximum glottic and tracheal area in order to confirm symmorphism.

Observations were made following single I.V. injections or during continuous I.V. infusions of sulphobromophthalein (BSP) in three Jersey calves (3-5 months of age) which had an indwelling hepatic vein catheter, surgically implanted under general anaesthesia. Simultaneous sampling of blood from a peripheral (jugular) vein and an hepatic vein enabled calculations of hepatic plasma flow (E.H.P.F.) based on the Fick principle. Estimates of E.H.P.F. in nine single injection experiments gave a mean flow of 38.6 ml X min-1 X kg-1 compared to 32.6 ml X min-1 X kg-1 estimated in seven continuous infusion experiments. The over-all mean haematocrit in the three calves was 30.0% and the E.H.P.F. values are equivalent to hepatic blood flows of 55 and 47 ml X min-1 X kg-1 respectively. In thirteen out of fourteen experiments the plasma clearance of BSP in jugular vein blood after a single I.V. injection of 5 mg BSP X kg-1 body weight was best fitted by a double exponential model of distribution of BSP. Parameters from these exponentials were used to calculate E.H.P.F. by the method of Clarkson, Hardy-Smith & Richards (1976) and gave values of 11.3 ml X min-1 X kg-1, clearly indicating that the method cannot be applied in conscious calves.

An Optomax Image Analyser has been used to carry out fibre-size analyses in six pairs of human recurrent laryngeal nerve and two pairs of recurrent nerves from adult giraffes. in every case the left recurrent laryngeal nerve was found to contain a greater number of large, fast-conducting fibres. Since this nerve is longer than the right, these findings may explain the simultaneous arrival of motor impulses to both sides of the laryngeal musculature.

Direct exposure of the superior mediastinum is essential when resecting subglottic tumours of the larynx, neoplasms of the cervical trachea or cervical oesophagus. This facilitates low resection of the trachea and clearance of the paratracheal nodes. This may best be carried out by removal of most of the manubrium sterni and both sternoclavicular joints and this operation has been performed in 22 patients with minimal morbidity or long term disability.

The operation of lateral rhinotomy does not perhaps receive as much attention as it might, despite the excellent exposure of the nasal passages and surrounding anatomy that can be obtained. A personal account of 100 consecutive operations for varying pathology is described in the hope that more surgeons may be aware of the value of this procedure.

Involvement of the thyroid cartilage attracts a high T rating in all systems of classification for carcinoma of the larynx. Evaluation of 145 patients with laryngeal cancer treated by total laryngectomy emphasizes the difficulties of preoperatively determining cartilage invasion. The operative specimen was serially sectioned and studied to determine the means by which ossified and nonossified thyroid cartilage is invaded by carcinoma. A minimum 5-year follow-up of these cases indicates the prognostic significance of such invasion.

The three-dimensional morphology of the mammalian larynx was studied for 15 years. Using specimens obtained from a wide variety of sources, efforts were made to correlate structure with function and thus explain the variations in size and morphology seen in over 150 families of mammals.

All the classification systems at present adopted for use in carcinoma of the maxillary sinus suffer from both intrinsic inaccuracies and an apparent failure to relate T (extent of primary tumor) categories to clinical experience of the spread of these tumors. Three systems are critically analyzed in relation to personal experience of 86 patients with sinus carcinoma and a fourth system proposed as a compromise solution to this problem.

Fifty-eight patients with osseous or fibro-osseous conditions affecting the craniofacial bones are reviewed in order to determine difficulty of diagnosis, natural history, and management. In many patients separation into individual categories is possible on clinical grounds alone. However, by correlating clinical examination with radiological and histological findings, it is clear that each of the pathological conditions discussed is a separate entity and not merely part of a broad spectrum of bony disorders.

During the period between 1965 and 1983, 101 pharyngolaryngoesophagectomies with primary pharyngogastric anastomosis were carried out for primary hypopharyngeal cancer at The Royal National Throat, Nose and Ear Hospital, London, England. The Hospital mortality rate was 11%; postoperative complications such as pleural effusion and regurgitation of bile occurred in all patients. Successful swallowing occurred in all patients before they left the hospital--usually within 2 wk of surgery. An actuarial survival rate of 58% was obtained for the entire group.

Ossification of the laryngeal cartilages is a random occurrence possibly related to age and sex. A wide variety of primate larynges have been examined radiologically, by macroscopic section or after whole organ serial section with the aim of determining presence of ossification. The results of this investigation will be presented in an attempt to establish possible correlation between structure, function and degree of ossification within each specific larynx. This is a unique enquiry which may assist in the understanding of ossification within the human larynx.

Three rather complicated cervical tracheo-esophageal problems and their appropriate management, are described. In each case, a tracheal defect required repair. In one case, fascia lata was used to close a defect in the posterior tracheal wall. In another, this type of repair was unsuccessful in one-stage closure of a large tracheo-esophageal fistula. A 7 cm defect of esophagus in heavily irradiated tissues was successfully reconstituted with transposed colon. The co-existing postirradiation tracheo-esophageal fistula was repaired at an earlier stage to ensure that the patient's recovery from the laparotomy would not be complicated by aspiration pneumonitis. Thoracotomy was not required, but resection of the clavicular head and mobilization of the origin of the sternomastoid were used to improve the transcervical exposure of the superior mediastinum. In the second case, a tracheal defect that involved the tracheal cartilage was repaired by sleeve resection and end-to-end anastomosis. In revision surgery of chronic cervical tracheal and subglottic stenosis, one can anticipate massive local scar formation. The densely fibrosed common wall between the trachea and the esophagus should be left completely with the esophagus and only the lateral and anterior remnants of the trachea excised to avoid iatrogenic recurrent nerve paralysis or inadvertent perforation into a traction diverticulum of the esophagus. One should anticipate the use of the laryngeal drop procedure to make up the tracheal defect. The suprathyroid tissues will be virgin, whereas the previous tracheal procedures will have reduced the length attainable below from tracheal remobilization. Suturing the chin toward the chest is an effective and well-tolerated prophylactic measure that prevents both extension of the neck after the operation and undue tension on the tracheal anastomosis. In the third case, closure of a vertical tracheal-esophageal fistula and repair of a tracheal defect were undertaken simultaneously. The procedure involved mobilizing the larynx from its hyoid attachments, dropping the larynx, and bringing the margins of the esophageal defect together transversely, as in a pyloroplasty. This application of the laryngeal drop procedure, not previously described, was effective.