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Ethical tensions arise daily in health care practice and are frequently related to health care system structures or policies. Collective case study methodology was adopted to examine ethical tensions reported by occupational therapists practicing in different settings in Southwestern Ontario, Canada. Inductive analysis involving multiple layers of coding was conducted. This article focuses on tensions related to systemic constraints. Participants reported ethical tensions related to balancing client priorities with those of health care services. Four themes related to systemic constraints were identified including imposed practices, ineffective processes, resource limitations, and lack of services. Therapists’ aims could be seen to align with an “ethic of care” and were seen to be in tension in light of systemic constraints. The findings raise issues related to occupational justice, particularly related to occupational alienation in occupational therapy practice, and open conversations related to neoliberalist health care agendas.

AbstractThis article aims to offer a definition of the international rule of law. It does this through clarifying the core objectives of a rule of law and examining whether the international system could include them. It demonstrates that there can be a definition of the international rule of law that can be applied to the international system. This definition of the international rule of law is not dependent on a simplistic application of a national rule of law, as it takes into account the significant differences between national and international legal systems. It seeks to show that the international rule of law is relative, rather than absolute, in its application, is not tied to the operation of the substance of international law itself, and it can apply to states, international organizations and non-state actors. It goes further to show that the international rule of law does exist and can be applied internationally, even if it is not yet fully actualized.

Radiocollared animals are frequently used to estimate detection probabilities in aerial surveys. The aircraft used to conduct these surveys may also have been used to aid in the capture of these animals, and recently captured animals may react to hearing or seeing the aircraft, changing their behavior in a way that calls into question the representativeness of estimated detection probabilities. We conducted a literature review and found 30 studies that used radiocollared animals to build sightability detection models; in ≥15 of these studies, the same aircraft was used to capture and survey animals. Although it is difficult to determine whether captured animals have different sighting probabilities than the rest of the target population, we used multiyear resighting data collected from moose (Alces alces) in Minnesota, elk (Cervus elaphus) in Washington, and mountain goats (Oreamnos americanus) in Washington and Alaska, to evaluate whether detection probabilities increased or decreased as a function of time since original capture. We did not detect statistically significant within‐individual time trends in detection probabilities, although we could not rule out the possibility of biologically significant results because confidence intervals on effect sizes were relatively wide. The lone exception to this rule was for the cohort of radiocollared moose in Minnesota, which exhibited a slight decrease in detection probabilities over time. Differences in detection probabilities for marked and unmarked animals may not be a significant problem for sightability models, provided that the source of the variability can be captured by model covariates (e.g., heterogeneity is tied to an individual's propensity to be in heavy cover). Nonetheless, capture‐related effects likely deserve greater consideration than currently afforded, and are critically important when applying simple mark–recapture abundance estimators (Lincoln–Petersen, mark–resight) that do not allow consideration of sighting covariates. © 2015 The Wildlife Society.

A series of experimental tests are carried out to aid in the optimal design of a jetmixer for a shallow circular basin. Mixing times for single and double jets with various orientations are investigated to determine the best arrangement. The best single jet is one directed along the diameter of the basin. A tangential jet near the basin perimeter has the longest mixing time. The best overall arrangement consists of tangential jet and 45° jet at a radius of 0.4 of the basin radius. An optimal design procedure is suggested.

The unsteady flow regime and the temperature mixing in temperaturestratified settling tanks associated with a warm influent are investigated by application of a numerical model with two different turbulence models. The model consists of a series of conservation equations for fluid mass, momentum, and temperature, with one version using the algebraic stress model and the other version using the conventional k‐εmodel. The simulation results are compared with existing experimental data for the temperature distribution. The velocity measurements were made under the same laboratory conditions that were used for the temperature surveys. The experimental results are presented and compared with those predicted by the numerical model.

A mathematical model for predicting the velocity field and suspended solids transport in secondary rectangular settling tanks is presented. The model is applied to investigate the effects of density stratification on the hydrodynamics in the settling tank, such as the behavior of the bottom current and surface return flow and solids concentration distribution. The model can be used to simulate the socalled density waterfall phenomenon at the front end of the settling tank. With the application of a double exponential relationship to describe the settling process of suspended solids with nonuniform particle sizes, the simulations of the solids concentration distribution in the lowconcentration environment can be significantly improved. By comparing the predictions with field measurements, this model is verified and generally good agreement is obtained.

The hydraulic jump has been extensively studied using physical models; however, very little data are available for the internal flow in prototype hydraulic jump stilling basins. A mathematical' model has been developed to help in the prediction of prototype performance from physical models. The technique used here is an extension of the strip integral method of R. Narayanan. The strip integral method uses velocity shape functions to permit the partial integration of the equations of motion. A Gaussian velocity distribution is used in the mixing zone and the power law is used in the inner layer. The mathematical model includes the bed shear, turbulent shear, the potential core, entrained air, centrifugal force and turbulence pressure. The model gives a fairly good prediction of the jump length, roller length, velocity distribution, water surface and pressure at the bed. The prediction of the growth of the boundary layer was not very good. The model indicated that the main effect of entrained air is the bulking of flow. The effects of centrifugal forces and turbulence pressures increase as F12and start to become significant for F1<5.

The numerical simulation of a sedimentation tank involves determining the velocity field and the sediment concentration distribution for the tank. In this study, the vertical velocity field is established by a finite difference model of the vorticitytransport stream function equations with a constant eddy viscosity. The eddy viscosity is obtained with the aid of a physical model. The numerical model is verified experimentally. The vorticity transport is treated by the Alternating Direction Implicit ADI method. A variable grid is used to maximize the effectiveness of the computational nodes. A weighted centereddifferenceupwind scheme is used for the convective terms. The twodimensional sediment transport convectivediffusion equation is solved by the same numerical approach used for the vorticity transport equation. The bottom boundary condition permitted reentrainment of settled solids. The model can be used for steady or unsteady solids transport. The model is applied to study the effect of reaction baffle submergence on solid removal. The model output is also compared with the CampDobbins method of determining solids removed in turbulent flow. The removal predicted by the numerical model is consistently less than that predicted by the CampDobbins approach.

The nonstratified steady flow hydrodynamics of rectangular sedimentation tanks is simulated using a combination of the strip integral and finite element methods. The strip integral method is generally a forward marching scheme in which the partial differential equations of continuity and momentum are reduced to a set of ordinary differential equations in terms of certain preselected parameters. These parameters, along with a set of shape functions, describe the velocity distribution. In this study three shape functions are chosen, corresponding to the boundary layer, the potential core, and the free mixing and recirculation zone. The shape functions were: 1 Power law in the boundary layer; 2 uniform velocity in the potential core; and 3 Gaussian distribution in the free mixing zone. The shape functions are chosen to allow recirculation above the mixing zone. A modified mixing length approach is used to introduce the effect of recirculation into the solution. A RungeKutta method is used to integrate the set of ordinary differential equations; a finite element solution is used in the withdrawal zone. The numerical results compare favorably with experimental velocity distributions obtained by laser anemometry and with available field data. The convective and mixing characteristics of the flow can be obtained from this model and used with a transport model to determine the removal efficiency of the tank.

Bacteriophage T5 did not grow at the nonpermissive temperature of 42 degrees C in Escherichia coli carrying a temperature-sensitive mutation in gyrB [gyrB(Ts)], but it did grow in gyrA(Ts) mutants at 42 degrees C. These findings indicate that the A subunit of host DNA gyrase is unnecessary, whereas the B subunit is necessary for growth of T5. The necessity for the B subunit was confirmed by a strong inhibition of T5 growth by novobiocin and coumermycin A1, which interfere specifically with the function of the B subunit of host DNA gyrase. However, T5 growth was also strongly inhibited by nalidixic acid, which interferes specifically with the function of the A subunit. This inhibition was due to the interaction of nalidixic acid with the A subunit and not just to its binding to DNA, because appropriate mutations in the gyrA gene of the host conferred nalidixic acid resistance to the host and resistance to T5 growth in such a host. The inhibition by nalidixic acid was also not due to a cell poison formed between nalidixic acid and the A subunit (K. N. Kreuzer and N. R. Cozzarelli, J. Bacteriol. 140:424-435, 1979) because nalidixic acid inhibited growth of T5 in a gyrA(Ts) mutant (KNK453) at 42 degrees C. We suggest that T5 grows in KNK453 at 42 degrees C because its gyrA(Ts) mutation is leaky for T5. Inhibition of T5 growth due to inactivation of host DNA gyrase was caused mainly by inhibition of T5 DNA replication. In addition, however, late T5 genes were barely expressed when host DNA gyrase was inactivated.

Demographic data show many populations of Rocky Mountain (Cervus elaphus nelsoni) and Roosevelt (Cervus elaphus roosevelti) elk have been declining over the last few decades. Recent work suggests that forage quality and associated animal nutritional condition, particularly in late summer and early autumn, influence reproduction and survival in elk. Therefore, we estimated seasonal nutritional condition of 861 female elk in 2,114 capture events from 21 herds in Washington, Oregon, Wyoming, Colorado, and South Dakota from 1998 to 2007. We estimated ingesta‐free body fat and body mass, and determined age, pregnancy status, and lactation status. We obtained estimates for most herds in both late winter–early spring (late Feb–early Apr) and in autumn (Nov–early Dec) to identify changes in nutritional condition of individuals across seasons. Body fat levels of lactating females in autumn were consistently lower than their non‐lactating counterparts, and herd averages of lactating elk ranged from 5.5% to 12.4%. These levels were 30–75% of those documented for captive lactating elk fed high‐quality diets during summer and autumn. Body fat levels were generally lowest in the coastal and inland northwest regions and highest along the west‐slope of the northern Cascades. Adult females in most herds lost an average of 30.7 kg (range: 5–62 kg), or about 13% (range: 2.6–25%) of their autumn mass during winter, indicating nutritional deficiencies. However, we found no significant relationships between spring body fat or change in body fat over winter with winter weather, region, or herd, despite markedly different winter weather among herds and regions. Instead, body fat levels in spring were primarily a function of fat levels the previous autumn. Thinner females in autumn lost less body fat and body mass over winter than did fatter females, a compensatory response, but still ended the season with less body fat than the fatter elk. Body fat levels of lactating females in autumn varied among herds but were unrelated to their body fat levels the previous spring. Within herds, thinner females exhibited a compensatory response during summer and accrued more fat than their fatter counterparts over summer, resulting in similar body fat levels among lactating elk in autumn despite considerable differences in their fat levels the previous spring. Level of body fat achieved by lactating females in autumn varied 2‐fold among herds, undoubtedly because of differences in summer nutrition. Thus, summer nutrition set limits to rates of body fat accrual of lactating females that in turn limited body condition across the annual cycle. Pregnancy rates of 2‐ to 14‐year‐old females ranged from 68% to 100% in coastal populations of Washington, 69% to 98% in Cascade populations of Washington and Oregon, 84% to 94% in inland northwestern populations of Washington and Oregon, and 78% to 93% in Rocky Mountain populations. We found evidence of late breeding, even in herds with comparatively high pregnancy rates. Mean body mass of calves (n= 242) in 3 populations was 75 kg, 81 kg, and 97 kg, representing 55–70% of potential mass for 6‐ to 8‐month‐old calves on high‐quality diets. Mean mass of 11 yearling females caught in autumn was 162 kg, approximately 70% of potential for autumn, and pregnancy rate was 27%. Mean mass of 28 yearlings caught in spring was 163 kg and pregnancy rate was 34%. Our data suggest widespread occurrence of inadequate summer nutrition. Summer ranges of just 3 herds supported relatively high levels of autumn body fat (11–13% body fat) and pregnancy rates (>90%) even among females that successfully raised a calf year after year. Most other summer ranges supported relatively low autumn levels of body fat (5–9% body fat), and reproductive pauses were common (<80% pregnancy rates). Overall, our data failed to support 2 common assumptions: 1) summer and early autumn foraging conditions are typically satisfactory to prevent nutritional limitations to adult fat accretion, pregnancy rates, and calf and yearling growth; and 2) winter nutrition and winter weather are the principal limiting effects on elk productivity. Instead, a strong interaction existed among level of summer nutrition, lactation status, and probability of breeding that was little affected by winter conditions—adequacy of summer nutrition dictated reproductive performance of female elk and growth as well as growth and development of their offspring in the Northwest and Rocky Mountains. Our work signals the need for greater emphasis on summer habitats in land management planning on behalf of elk. © 2013 The Wildlife Society. Los datos demográficos disponibles muestran que las poblaciones de alce de las Montañas Rocosas (Cervus elaphus nelsoni) y de alce de Roosevelt (Cervus elaphus roosevelti) han ido disminuyendo en las últimas décadas. Estudios recientes sugieren que la calidad del forraje y el estado nutricional del alce, especialmente a finales del verano y principios del otoño, influyen en su reproducción y supervivencia. En consecuencia, se decidió estimar el estado nutricional de 861 hembras de alce, en 2114 eventos de captura, de 21 rebaños en Washington, Oregón, Wyoming, Colorado y Dakota del Sur desde 1998 al 2007. Se estimó la grasa corporal (sin incluir el bolo alimentario) y la masa corporal y también se determinó la edad, el estado de embarazo y el estado de lactancia de estos animales. Estas estimaciones fueron obtenidas, para la mayoría de los rebaños, a finales del invierno y principios de la primavera (finales de febrero y principios de abril) así como en otoño (noviembre y principios de diciembre) con el fin de identificar los cambios en el estado nutricional de los individuos a través de las estaciones. En otoño, los niveles de grasa corporal de las hembras que daban de lactar fueron consistentemente más bajos que aquellos de las hembras que no daban de lactar y el promedio de hembras en estado de lactancia varió entre 5.5% y 12.4%. Estos niveles equivalen al 30–75% de aquellos documentados en la literatura para hembras en cautividad, en estado de lactancia y alimentadas con dietas de alta calidad durante el verano y el otoño. Los niveles de grasa corporal fueron generalmente más bajos en regiones costeras y al interior del Noroeste americano, mientras que los niveles más altos fueron observados a lo largo de la ladera occidental de las Cascadas del Norte. Durante el invierno, las hembras adultas en la mayoría de los rebaños perdieron un promedio de 30.7 kg (rango: 5–62 kg), o alrededor del 13% (rango: 2.6–25%) de la masa corporal registrada en otoño, lo que es indicativo de deficiencias nutricionales. Sin embargo, no se encontraron correlaciones significativas entre la grasa corporal registrada en primavera, o el cambio en la grasa corporal durante el invierno, y el clima invernal, la región o el rebaño, a pesar de los diferentes climas invernales entre los rebaños y las regiones. Por otro lado, se observó que los niveles de grasa corporal en la primavera fueron principalmente una función de los niveles de grasa del otoño precedente. Las hembras más delgadas perdieron menos grasa corporal y masa corporal durante el invierno que las hembras más gordas—lo que podría interpretarse como una respuesta compensatoria—pero aún así terminaron la temporada con menos grasa corporal que las hembras más gordas. Los niveles de grasa corporal de las hembras que daban de lactar en otoño variaron entre los rebaños, pero no guardaron ninguna relación con los niveles de grasa corporal de la primavera anterior. Dentro de los rebaños, las hembras más delgadas mostraron una respuesta compensatoria durante el verano y acumularon más grasa que las hembras más gordas a lo largo del verano, dando lugar a similares niveles de grasa corporal entre las hembras que daban de lactar en otoño a pesar de las considerables diferencias en sus niveles de grasa de la primavera anterior. El nivel de grasa corporal adquirido por las hembras que daban de lactar en otoño varió el doble entre los rebaños, sin duda debido a las diferencias en la alimentación durante el verano. Así, el nivel de nutrición alcanzado durante el verano parece haber establecido restricciones en las tasas de acumulación de grasa corporal de las hembras que daban de lactar, lo que a su vez limitó su condición física a través del ciclo anual. Las tasas de embarazo de las hembras de entre 2 a 14 años de edad varió entre 68% y 100% en las poblaciones costeras de Washington, entre 69% y 98% en las poblaciones de Cascade de Washington y Oregón, entre 84% a 94% en las poblaciones del interior del noroeste de Washington y Oregón, y entre 78% y 93% en las poblaciones de las Montañas Rocosas. Se encontró evidencia de reproducción tardía incluso en rebaños con tasas de embarazo relativamente altas. La media de masa corporal de los terneros (n= 242) en tres poblaciones fue de 75, 81 y 97 kg, es decir entre 55% y 70% de la masa potencial de terneros de 6 a 8 meses de edad alimentados con dieta de alta calidad. La media de masa corporal de 11 becerras atrapadas en otoño fue de 162 kg, lo que equivale aproximadamente a 70% de su masa potencial en otoño; su tasa de embarazo fue del 27%. La media de masa corporal de 28 becerras atrapadas en primavera fue de 163 kg y su tasa de embarazo fue del 34%. Nuestros datos sugieren una amplia incidencia de malnutrición durante el verano. Las zonas de alimentación de verano de sólo tres rebaños sustentaron niveles relativamente altos de grasa corporal de otoño (11–13%) y tasas de embarazo (>90%) incluso entre las hembras que lograron criar un ternero año tras año. La mayoría de las otras zonas de alimentación de verano sustentaron niveles de grasa corporal relativamente bajos (5–9%) y en esas zonas las pausas reproductivas fueron comunes (tasas de embarazo <80%). En general, nuestros datos no apoyan dos supuestos comunes: 1) las condiciones de búsqueda de forraje durante el verano y principios del otoño suelen ser satisfactorias para evitar las limitaciones nutricionales asociadas a la acumulación de grasa en un alce adulto, a las tasas de embarazo y al crecimiento de terneros y becerros y; 2) la nutrición invernal y el clima invernal son los principales limitantes de la productividad de un alce. Por el contrario, existe una fuerte interacción entre el nivel de nutrición en verano, el estado de lactancia y la probabilidad de reproducción que se vio poco afectada por las condiciones invernales—una adecuada nutrición en verano determinó la performance reproductiva de las hembras de alce así como el crecimiento y el desarrollo de sus crías en el Noroeste americano y las Montañas Rocosas. Nuestro trabajo señala la necesidad de dar un mayor énfasis a los hábitats de verano cuando se considere la planificación de la gestión territorial en nombre del alce. Des données démographiques montrent que de nombreuses populations de wapitis des Rocheuses (Cervus elaphus nelsoni) et de wapitis de Roosevelt (Cervus elaphus roosevelti) ont connu un déclin au cours des dernières décennies. De récents travaux semblent indiquer que la qualité du fourrage et son effet sur l'état nutritionnel de l'animal, notamment à la fin de l'été et au début de l'automne, influencent la reproduction et la survie du wapiti. Nous avons estimé l'état nutritionnel saisonnier de 861 femelles dans 21 troupeaux au cours de 2 114 campagnes de capture réalisées dans les états de Washington, de l'Oregon, du Wyoming, du Colorado et du Dakota du Sud entre 1998 et 2007. Nous avons estimé le taux de lipides sans ingesta et la masse corporelle et avons établi l'âge, le taux de gestation et le taux de lactation. Pour la plupart des troupeaux, nous avons fait nos estimations à la fin de l'hiver/au début du printemps (fin fév.‐début avr.) et à l'automne (nov.‐début déc.) afin de déterminer si l'état nutritionnel des individus variait au cours des saisons. Le taux de lipides des femelles lactantes à l'automne était toujours plus faible que celui des femelles non lactantes, et le pourcentage moyen de femelles en lactation dans les troupeaux variaient entre 5,5% et 12,4%. Ce taux correspondait à 30–75% des réserves lipidiques documentées pour des femelles lactantes en captivité et qu'on nourrissait avec du fourrage de haute qualité à l'été et en automne. Les troupeaux des régions côtières et des régions intérieures du nord‐ouest présentaient généralement les taux de lipides les plus bas, tandis que ceux situés sur le flanc ouest de la partie nord de la chaîne des Cascades présentaient les taux les plus élevés. Dans la plupart des troupeaux, les femelles adultes perdaient une moyenne de 30,7 kg (intervalle: 5–62 kg) ou environ 13% (intervalle: 2,6–25%) de leur masse automnale au cours de l'hiver, ce qui indique une carence nutritionnelle. Par contre, nous n'avons pas trouvé de relations significatives entre les réserves lipidiques printanières ou des variations dans les réserves lipidiques au cours de l'hiver et les conditions météo en hiver, la région ou le troupeau, en dépit des conditions météo hivernales vraiment différentes observées entre les troupeaux ou les régions. Au contraire, le taux de lipides printanier était plutôt une fonction du taux de lipide de l'automne précédent. Les femelles plus maigres à l'automne ont perdu moins de graisses et de masse corporelle durant l'hiver que les femelles plus grosses, une réaction compensatoire certes, mais qui n'a pas empêché les femelles plus maigres d'avoir moins de réserves lipidiques à la fin de la saison que les femelles plus grosses. Le taux de lipides des femelles lactantes à l'automne variait parmi les troupeaux, mais n'était pas relié à leur taux de lipides du printemps précédent. À l'intérieur d'un même troupeau, une réaction compensatoire se déclenchait en été chez les femelles plus maigres, et elles accumulaient plus de graisses en été que les femelles plus grosses, si bien que toutes les femelles lactantes à l'automne avaient le même taux de lipides en dépit de différences considérables au printemps. Le taux de lipides des femelles lactantes à l'automne variait du simple au double entre les troupeaux, en raison sans aucun doute de différences dans leur régime alimentaire d'été. C'est donc la nourriture consommée en été qui a limité le taux d'accumulation des lipides chez les femelles en lactation et qui a donc limité leur état d'engraissement au cours du cycle annuel. Le taux de gestation des femelles âgées entre 2 et 14 ans variait de 68% à 100% dans les populations côtières de l'état de Washington, de 69% à 98% dans celles de la chaîne des Cascades de l'état de Washington et de l'état de l'Oregon, de 84% à 94% dans celles des régions intérieures du nord‐ouest de l'état de Washington et de l'état de l'Oregon et de 78% à 93% dans celles des Rocheuses. Nous avons noté des cas d'accouplement tardif, même chez les populations ayant un taux de gestation relativement élevé. La masse corporelle moyenne des petits (n= 242) dans 3 populations était de 75 kg, 81 kg, et 97 kg, ce qui représentait 55% à 70% de la masse potentielle des petits âgés de 6 à 8 mois avec un régime alimentaire de haute qualité. La masse moyenne de 11 femelles âgées d'un an et capturées à l'automne était de 162 kg, environ 70% de la masse potentielle d'une femelle à l'automne, et le taux de gestation était de 27%. La masse moyenne de 28 femelles âgées d'un an et capturées au printemps était de 163 kg et le taux de gestation était de 34%. Nos données semblent indiquer que les wapitis ont un régime alimentaire inadéquat en été et qu'il s'agit d'une situation généralisée. Les aires de répartition estivales de seulement 3 troupeaux sont parvenus à soutenir un taux de lipides et un taux de gestation relativement élevés en automne (taux de lipides de 11–13% et taux de gestation >90%), même parmi les femelles qui avaient réussi, année après année, à élever un petit. La plupart des autres aires de répartition soutenaient un taux de lipides peu élevé en automne (5% à 9%), et il était courant de voir des pauses reproductives (taux de gestation <80%). Dans l'ensemble, nos données n'ont pas réussi à démontrer deux hypothèses répandues: 1) les conditions de fourrage en été et au début de l'automne sont généralement satisfaisantes pour prévenir les carences nutritionnelles chez les adultes en matière d'accrétion des lipides, de taux de gestation et de croissance des petits et des jeunes wapitis d'un an; et 2) l'alimentation et les conditions météo hivernales sont les principaux facteurs limitatifs dans la reproduction du wapiti. Au contraire, nos données ont montré qu'il existait une très forte corrélation entre le régime alimentaire d'été, le taux de lactation et la probabilité d'accouplement, corrélation qui était peu influencée par les conditions hivernales. C'était plutôt le caractère adéquat du régime alimentaire d'été qui régissait la performance reproductive des wapitis femelles et la croissance et le développement de leur progéniture dans les montages des régions du nord‐ouest et des Rocheuses. Nos travaux démontrent la nécessité de mettre davantage l'accent sur les habitats d'été dans les plans d'aménagement forestier en ce qui concerne les wapitis.

Raw counts from aerial surveys make no correction for undetected animals and provide no estimate of precision with which to judge the utility of the counts. Sightability modeling and double-observer (DO) modeling are 2 commonly used approaches to account for detection bias and to estimate precision in aerial surveys. We developed a hybrid DO sightability model (model MH) that uses the strength of each approach to overcome the weakness in the other, for aerial surveys of elk (Cervus elaphus). The hybrid approach uses detection patterns of 2 independent observer pairs in a helicopter and telemetry-based detections of collared elk groups. Candidate MHmodels reflected hypotheses about effects of recorded covariates and unmodeled heterogeneity on the separate front-seat observer pair and back-seat observer pair detection probabilities. Group size and concealing vegetation cover strongly influenced detection probabilities. The pilot's previous experience participating in aerial surveys influenced detection by the front pair of observers if the elk group was on the pilot's side of the helicopter flight path. In 9 surveys in Mount Rainier National Park, the raw number of elk counted was approximately 80–93% of the abundance estimated by model MH. Uncorrected ratios of bulls per 100 cows generally were low compared to estimates adjusted for detection bias, but ratios of calves per 100 cows were comparable whether based on raw survey counts or adjusted estimates. The hybrid method was an improvement over commonly used alternatives, with improved precision compared to sightability modeling and reduced bias compared to DO modeling. © 2013 The Wildlife Society.

The North Cascades (Nooksack) elk (Cervus elaphus) population declined during the 1980s, prompting a closure to state and tribal hunting in 1997 and an effort to restore the herd to former abundance. In 2005, we began a study to assess the size of the elk population, judge the effectiveness of restoration efforts, and develop a practical monitoring strategy. We concurrently evaluated 2 monitoring approaches: sightability correction modeling and mark-resight modeling. We collected data during February–April helicopter surveys and fit logistic regression models to predict the sightability of elk groups based on group and environmental variables. We used an information-theoretic criterion to compare 9 models of varying complexity; the best model predicted sightability of elk groups based on 1) transformed (log2) group size, 2) forest canopy cover (%), and 3) a categorical activity variable (active vs. bedded). The sightability model indicated relatively steady and modest herd growth during 2006–2011, but estimates were less than minimum-known-alive counts. We also used the logit-normal mixed effects (LNME) mark-resight model to generate estimates of total elk population size and the sizes of the adult female and branch-antlered male subpopulations. We explored 15 LNME models to predict total population size and 12 models to predict subpopulations. Our results indicated individual heterogeneity in resighting probabilities and variation in resighting probabilities across sexes and some years. Model-averaged estimates of total population size increased from 639 (95% CI?=?570–706) in spring 2006 to 1,248 (95% CI?=?1,094–1,401) in 2011. We estimated the adult female subpopulation increased from 381 (95% CI?=?338–424) in spring 2006 to 573 (95% CI?=?507–639) by 2011. The branch-antlered male subpopulation estimates increased from 87 (95% CI?=?54–119) to 180 (95% CI?=?118–241) from spring 2006 to spring 2011. The LNME model estimates were greater than sightability model estimates and minimum-known-alive counts. We concluded that mark-resight performed better and was a viable approach for monitoring this small elk population and possibly others with similar characteristics (i.e., small population and landscape scales), but this approach requires periodic marking of elk; we estimated mark-resight costs would be about 40% greater than sightability model application costs. The utility of sightability-correction modeling was limited by a high proportion of groups with low detectability on our densely forested landscape. © 2012 The Wildlife Society.

We studied survival of elk (Cervus elaphus) =1?yr old and quantified mortality sources in the Blue Mountains of Washington, 2003–2006, following a period of extensive poaching. The population was managed under a spike-only general hunting season, with limited permits for larger males and for females. We radiomarked 190 elk (82 males and 39 females >1?yr old and 65 males 11 months old), most with rumen transmitters and neck radiocollars; 60 elk only received rumen transmitters. We estimated annual survival using known fate models and explored survival differences among sex and age classes and in 2 potentially different vulnerability zones for males. We found little support for differences in survival between younger (2–3-yr old) and older (=4-yr old) branch-antlered males or zone differences for yearling males. A model with zone differences for branch-antlered males was the second ranked model and accounted for 14% of the available model weight. From the best-supported models, we estimated annual survival for yearling males at 0.41 (95% CI: 0.29–0.53). We estimated pooled adult female survival at 0.80 (95% CI: 0.64–0.93); when an age-class effect was included, point estimates were higher for prime-aged females (2–11?yr: S?=?0.81 [0.70–0.88]) than for older females (=12?yr: S?=?0.72 [0.56–0.83]), but confidence intervals broadly overlapped. Only 1 of 7 models with a female age effect on survival was among the competitive models. For branch-antlered males, survival ranged 0.80–0.85, depending on whether zone variation was modeled. We recorded 78 deaths of radiomarked elk. Human-caused deaths (n?=?55) predominated among causes and most were of yearling males killed during state-sanctioned hunts (n?=?28). Most subadult male deaths were from tribal hunting (n?=?5), and most mature males died from natural causes (n?=?6) and tribal hunting (n?=?5). We detected few illegal kills (n?=?4). Our results suggest that increased enforcement effectively reduced poaching, that unreported tribal harvest was not a trivial source of mortality, and that spike-only general seasons were effective in recruiting branch-antlered males. © 2011 The Wildlife Society.

Abstract:Because they do not require sacrificing animals, body condition scores (BCS), thickness of rump fat (MAXFAT), and other similar predictors of body fat have advanced estimating nutritional condition of ungulates and their use has proliferated in North America in the last decade. However, initial testing of these predictors was too limited to assess their reliability among diverse habitats, ecotypes, subspecies, and populations across the continent. With data collected from mule deer (Odocoileus hemionus), elk (Cervus elaphus), and moose (Alces alces) during initial model development and data collected subsequently from free-ranging mule deer and elk herds across much of the western United States, we evaluated reliability across a broader range of conditions than were initially available. First, to more rigorously test reliability of the MAXFAT index, we evaluated its robustness across the 3 species, using an allometric scaling function to adjust for differences in animal size. We then evaluated MAXFAT, rump body condition score (rBCS), rLIVINDEX (an arithmetic combination of MAXFAT and rBCS), and our new allometrically scaled rump-fat thickness index using data from 815 free-ranging female Roosevelt and Rocky Mountain elk (C. e. rooseveltiand C. e. nelsoni) from 19 populations encompassing 4 geographic regions and 250 free-ranging female mule deer from 7 populations and 2 regions. We tested for effects of subspecies, geographic region, and captive versus free-ranging existence. Rump-fat thickness, when scaled allometrically with body mass, was related to ingesta-free body fat over a 38–522-kg range of body mass (r2= 0.87; P< 0.001), indicating the technique is remarkably robust among at least the 3 cervid species of our analysis. However, we found an underscoring bias with the rBCS for elk that had >12% body fat. This bias translated into a difference between subspecies, because Rocky Mountain elk tended to be fatter than Roosevelt elk in our sample. Effects of observer error with the rBCS also existed for mule deer with moderate to high levels of body fat, and deer body size significantly affected accuracy of the MAXFAT predictor. Our analyses confirm robustness of the rump-fat index for these 3 species but highlight the potential for bias due to differences in body size and to observer error with BCS scoring. We present alternative LIVINDEX equations where potential bias from rBCS and bias due to body size are eliminated or reduced. These modifications improve the accuracy of estimating body fat for projects intended to monitor nutritional status of herds or to evaluate nutrition's influence on population demographics.

Fecal bacteria have traditionally been used as indicator organisms to monitor the quality of recreational waters. Recent work has questioned the robustness of traditional indicators, particularly at seawater bathing beaches. For example, a study of Florida beaches found unexpectedly high abundances of Escherichia coli, fecal coliforms, and enterococci in beach sand. The aim of the present study was to explain these abundances by assessing the survival of E. coliand enterococci in beach sand relative to seawater. We used a combination of quantitative laboratory mesocosm experiments and field observations. Results suggested that E. coliand enteroccocci exhibited increased survivability and growth in sand relative to seawater. Because fecal bacteria are capable of replicating in sand, at least under controlled laboratory conditions, the results suggest that sand may be an important reservoir of metabolically active fecal organisms. Experiments with “natural” mesocosms (i.e., unsterilized sand or water rich in micropredators and native bacteria) failed to show the same increases in fecal indicators as was found in sterile sand. It is postulated that this was due to predation and competition with indigenous bacteria in these “natural” systems. Nonetheless, high populations of indicators were maintained and recovered from sand over the duration of the experiment as opposed to the die‐off noted in water. Indicator bacteria may wash out of sand into shoreline waters during weather and tidal events, thereby decreasing the effectiveness of these indicators as predictors of health risk and complicating the interpretations for water quality managers.

AbstractSeventy-nine species of weevils are newly reported in Nova Scotia and 66 species are newly reported on Prince Edward Island, increasing the known provincial weevil faunas to 244 and 92 species, respectively. Thirty-six species are recorded for the first time in the Maritime Provinces; of these, Ceutorhynchus pallidactylus(Marsham), Listronotus dietziO'Brien, Corthylus columbianusHopkins, and Orchidophilus aterrimus(Waterhouse) are recorded for the first time in Canada. Orchidophilus aterrimushas been collected only in exotic domesticated orchids and is not established in the wild. Fourteen species previously recorded on Cape Breton Island, Nova Scotia, are reported from the provincial mainland. Four species ? Curculio sulcatulus(Casey), Ceutorhynchus squamatusLeConte, Tachyerges niger(Horn), and Ips calligraphus(Germar) ? are removed from the faunal list of Nova Scotia, and three species ? Temnocerus cyanellus(LeConte), Curculio nasicus(Say), and Cryphalus ruficollis ruficollisHopkins ? are removed from the faunal list of Prince Edward Island. The combined known weevil fauna of the Maritime Provinces now totals 290 species. The adequacy of collection effort is discussed and in Nova Scotia, where collection effort has been greatest, distribution patterns of selected groups of species are examined. Island faunas are discussed with respect to those of Prince Edward Island and Cape Breton Island. Regional biogeographic patterns of species are also discussed, including possible disjunct populations in Nova Scotia and species that may not have crossed the isthmus of Chignecto to colonize Nova Scotia. Attention is drawn to the long history of introduced species in the region and to ongoing introductions through an examination of the earliest records for the 60 introduced species found in the region.

AbstractThe long-horned beetles (Cerambycidae) of Prince Edward Island are surveyed. Records of 28 species of cerambycids new to the province are provided, increasing the known fauna of this family on the island to 38 species. One species, Pogonocherus penicillatusLeConte, is removed from the list of the province's fauna. Additionally, one exotic species, Rhopalophora tenuis(Chevrolat), is reported as intercepted from merchandise imported from Mexico. This fauna is examined in relation to its distribution within the province, biogeographical components, island biogeography, the composition of the regional fauna, the impact of anthropogenic activities, and adventive species. All these provide lessons to improve our understanding of the biodiversity of the province.

Removal of the zona pellucida is known to affect mouse development to term. Zygotes were recovered immediately after fertilization and their zona pellucida removed by exposure to pronase before culture and comparison with zona-intact embryos. The effect of removing the zona pellucida was assessed in terms of embryo development to blastocyst, DNA methylation, histone acetylation, and expression of three developmentally regulated genes. No significant differences were seen in percentage of embryos that developed to the blastocyst stage. However, zona-free embryos showed a significant reduction in the DNA methylation level at two-cell and four-cell stages, but no differences at pronuclear, morula, and blastocyst stages, as observed by immunofluorescence. Mechanical or enzymatic removal of the zona pellucida showed similar DNA methylation staining patterns at the two-cell stage. The time when the zona pellucida was removed appears to influence the levels of DNA methylation. When zona removal was delayed for 8 h, there was no difference in DNA methylation levels between zona-free and zona-intact two-cell embryos, indicating that the critical time is early on, between 1 and 8 h postfertilization. In contrast, when immunofluorescence analysis of histone acetylation was performed, no significant differences were seen between zona-free and zona-intact embryos at any of the developmental stage. Similarly, no differences were found regarding the onset of transcription of Dnmt1s, Nanog,and Fgf4genes.

We have evaluated the potential of liver-directed, helper-dependent adenoviral (HDAd) vector-mediated gene therapy in the hemophilia B dog. Two dogs were injected intravenously with HDAd (3 × 1012 VP/kg) bearing a liver-restricted canine coagulation factor IX (FIX) expression cassette. After injection, the whole blood clotting time for both dogs declined from >60 min to ≤20 min for at least 604 and 446 days, respectively. Peak FIX activities of 34.1 and 129.2% were detected at 12×14 days and then slowly declined to 2 to 5% by 120 days and stabilized at these therapeutic levels for at least 418 and 257 days. For one dog, a peak FIX level of 500 ng/ml was achieved and stabilized at >170 ng/ml for at least 256 days. For the other dog, a peak FIX level of 1258 ng/ml was achieved and stabilized at >400 ng/ml for at least 213 days. Inhibitor formation was not evident in either animal. Importantly, whereas untreated hemophilia B dogs suffer five or six spontaneous bleeds per year, the treated dogs suffered no such bleeds postinjection. Significantly, this study is the first to demonstrate long-term phenotypic correction of a genetic disorder in a large animal with HDAd. Although no evidence of chronic toxicity was observed in either animal, systemic vector administration at 3 × 1012 VP/kg was accompanied by acute, albeit transient and variable laboratory abnormalities (alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, creatine phosphokinase, and platelet counts). The results of this study highlight both the potential benefit and the risk associated with systemic intravascular delivery of high-dose HDAd for liver-directed gene therapy.

This paper presents an investigation of velocity distribution in steady, uniform flows in smooth rectangular channels. Theoretical study and experimental data show that the near wall velocity distribution in 3-D channels cannot be represented well by the classical log-law where the shear velocities are identical on both sides of the equation (Tracy and Lester, US Department of Interior,Washington, DC, 1961, pp. A1-A18). This paper examines the appropriate expressions of two shear velocities that may be different. In the light of Tracy and Lester's work, this study found that when the measured near wall velocity and wall normal distance are normalized by the global shear velocity and the local shear velocity, then the near wall velocity can be described by the well-known wall function without an empirical coefficient. The basic mechanism is attributed to the concept proposed by Yang and Lim [J. Hydraul. Engng. ASCE123 (1997) 684] that surplus mechanical energy is transported towards boundary along shortest path. The derived equations are in good agreement with experimental data in the literature.

The dominant international legal theories are based on an understanding of international law in terms of a solely state-based system. This article challenges those theories in the context of the practice of the participants in the international legal system. It proposes an inclusive conceptual approach which acknowledges that non-state actors have distinct and independent international rights, responsibilities, and abilities to bring claims, as well as clear roles in the creation, development, and enforcement of international law, which are separate to that of states. While states currently have a primary role in the international legal system, this role is not exclusive.

Hemophilia B is a bleeding disorder resulting from factor IX (FIX) deficiency that might be treated with gene therapy. Neonatal delivery would correct the disease sooner than would transfer into adults, and could reduce immunological responses. Neonatal mice were injected intravenously with a Moloney murine leukemia virus–based retroviral vector (RV) expressing canine FIX (cFIX). They achieved 150% to 280% of normal cFIX antigen levels in plasma (100% is 5 μg/mL), which was functional in vitro and in vivo. Three newborn hemophilia B dogs that were injected intravenously with RV achieved 12% to 36% of normal cFIX antigen levels, which improved coagulation tests. Only one mild bleed has occurred during 14 total months of evaluation. This is the first demonstration of prolonged expression after neonatal gene therapy for hemophilia B in mice or dogs. Most animals failed to make antibodies to cFIX, demonstrating that neonatal gene transfer may induce tolerance. Although hepatocytes from newborns replicate, those from adults do not. Adult mice therefore received hepatocyte growth factor to induce hepatocyte replication prior to intravenous injection of RV. This resulted in expression of 35% of normal cFIX antigen levels for 11 months, although all mice produced anti-cFIX antibodies. This is the first demonstration that high levels of FIX activity can be achieved with an RV in adults without a partial hepatectomy to induce hepatocyte replication. We conclude that RV-mediated hepatic gene therapy is effective for treating hemophilia B in mice and dogs, although the immune system may complicate gene transfer in adults.

Embryo transfer and pregnancy maintenance strategies in pigs were evaluated with reference to situations in which limited numbers of viable embryos or micromanipulated embryos are available, such as pig cloning. Development of embryos with compromised zona pellucida was compared with development of embryos with intact zona pellucida. Micromanipulation had no effect on blastocyst production rates after development in vivo or in vitro, but development in vivo improved the number of embryos reaching the blastocyst stage. Transfer of embryos with compromised zona pellucida resulted in live piglets. Several hormone treatments to maintain pregnancy were tested in a model in which three embryos were transferred into unmated recipient gilts, compared with transfer of three embryos into mated recipients. None of the hormonal treatments resulted in pregnancy rates of more than 25% at term and no more than 9% of transferred embryos survived, in comparison with 50% of the mated recipients successfully carrying 25% of transferred embryos. Lastly, the developmental potential of parthenogenetic embryos was assessed and 62% of transferred embryos resulted in pregnancies, none of which continued beyond day 55 of gestation. After co-transfer of three fertilized embryos with 55-60 parthenogenetic embryos into each of six recipients, two live piglets were delivered. The results from the present study indicate that transfer of zona pellucida compromised embryos can yield litters of normal piglets. In addition, it was demonstrated in a model system involving the transfer of three fertilized embryos into mature gilts that hormonal pregnancy maintenance strategies support a low proportion of embryos to term. Lastly, the present study shows for the first time a comparably effective but novel alternative for pregnancy maintenance in the pig involving the co-transfer of parthenote embryos.

The lipids of Tropaeolum speciosum(T. speciosum) are a rich source of naturally occurring nervonic acid (24:1n-9). We report that adding a T. speciosumoil supplement to a semi-purified diet significantly increased the amount of 24:1n-9 in liver and heart, but not brain, sphingomyelin (SM) of young rats. The bioavailability of 24:1n-9 from the lipids of T. speciosumwas similar to that of 24:1n-9 ethyl ester in this rat bioassay.

A three‐dimensional hydrodynamic model has been developed for turbulent flows with free surface. In the horizontal x–y‐plane, a boundary‐fitted curvilinear co‐ordinate system is adopted, while in the vertical direction, a σ‐co‐ordinate transformation is used to represent the free surface and bed topography or lower boundary. Using the finite volume method, the convection terms are discretized using Roe's second‐order‐accurate scheme. The governing equations are solved in a collocated grid system by a fractional three‐step implicit algorithm that has been developed to handle the velocity–pressure–depth coupling problem of free surface incompressible fluid flows. The present study is the extension of previous work to three‐dimensional turbulent flows. The model has been applied to three test cases. Comparison with available data shows that the model developed is successful, and is valuable to engineering application. © 1998 John Wiley & Sons, Ltd.

AbstractSphaerularia bombiDufour is an internal nematode parasite of bumble bee queens in North America and Europe. Infection functionally castrates the bee. Here we document the prevalence and intensity of S. bombiinfections in seven species of Bombusand three species of Psithyruson Cape Breton Island, Nova Scotia, Canada. We found dramatic variation in prevalences among Bombusspp., and some evidence that prevalence increased as the nesting season progressed. Also, we report S. bombiin the bumble bee nest parasite Psithyrus insularis(Smith), the first record for the genus in North America.

AbstractWe assessed enzyme variability in a solitary leafcutter bee, Megachile rotundata(Fabricius), and found sufficient variability to compare relatedness among progeny in a nest in two samples: (1) nests with an associated adult female (putative mother) and (2) nests with out-of-sequence male progeny (M. rotundata, like most cavity-nesting solitary aculeates, usually provisions all female cells in a nest before any male cells). Estimates of relatedness from nests with associated adult females were consistent with the progeny in a nest being closely related and the offspring of a single, once-mated female. The relatedness estimates from nests with out-of-sequence males were all much lower, suggesting some combination of nest parasitism, nest usurpation, nest abandonment, and multiply mated females in these nests. The high levels of relatedness among female progeny in the first sample, as expected for full sisters in a haplodiploid system, are considered with respect to the evolution of social behaviour in the Hymenoptera. Besides higher estimates of relatedness, the nests with an associated female also had a lower male:female sex ratio than did nests with out-of-sequence males.

The behavior of flow in rectangular settling tanks has been studied under different flow conditions using statistical analysis of 13 configurations. The mean and root mean square (rms) velocities throughout the tank have been measured and the main features of the flow patterns, for example, the size of eddies, potential core, growth of the boundary layer, and the turbulence distribution within the tank have been studied. The energy balance is investigated on the basis of the mean kinetic energy and the turbulent kinetic energy. The rms of the horizontal velocity is used to represent the turbulence in the tanks.

Clarifier hydrodynamics plays an important role in the activated sludge process. Attention has long been focused on the biological behavior of the aeration basin in the secondary treatment system. One-dimensional settler models or empirical relationships have typically been coupled in wastewater treatment plant simulation systems to represent the clarifier. The research on the hydrodynamic aspects of the process are currently restricted to a clarifier uncoupled from the aeration basin. In this paper, a dynamic model of the activated sludge process is presented in which balanced emphasis is put on the hydrodynamic aspect of the system. The model integrates a biological reaction submodel for an aeration basin with a two-dimensional hydrodynamic solids transport submodel for the secondary clarifier. A verification of the model is carried out against a set of field data and shows good agreement. The model has been used to investigate the response and the interdependency of the aerator and clarifier in the activated sludge system.

Dimensionless equations for the hydraulic conductivity of crushed rock and river gravel have been developed on the basis of approximately 1250 permeameter tests. Experimental data of a number of researches were used in the correlations. Grain sizes varied from .55 to .79 mm and pore Reynolds numbers were in the range of .001 to 20,000. The data are divided into two flow regimes and separate equations are proposed for each regime. Surface roughness is incorporated in the equations for the high Reynolds number regime. The correlations also account for the wall effect.

It is shown that free stream turbulence can cause apparent scale effects in certain hydraulic models, namely, those involving highly curvilinear flow. These apparent scale effects can be more than triple the normal boundary layer displacement effect.Sluice gate models with variable inclinations were used to investigate this effect. It was found that high free stream turbulence could increase the contraction coefficient by more than 10% relative to the theoretical solution.

The nonstratified steady flow hydrodynamics of rectangular sedimentation tanks is simulated using a combination of the strip integral and finite element methods. The strip integral method is generally a forward marching scheme in which the partial differential equations of continuity and momentum are reduced to a set of ordinary differential equations in terms of certain preselected parameters. These parameters, along with a set of shape functions, describe the velocity distribution. In this study three shape functions are chosen, corresponding to the boundary layer, the potential core, and the free mixing and recirculation zone. The shape functions were: (1) Power law in the boundary layer; (2) uniform velocity in the potential core; and (3) Gaussian distribution in the free mixing zone. The shape functions are chosen to allow recirculation above the mixing zone. A modified mixing length approach is used to introduce the effect of recirculation into the solution. A Runge‐Kutta method is used to integrate the set of ordinary differential equations; a finite element solution is used in the withdrawal zone. The numerical results compare favorably with experimental velocity distributions obtained by laser anemometry and with available field data. The convective and mixing characteristics of the flow can be obtained from this model and used with a transport model to determine the removal efficiency of the tank.

The occurrence of liver haemorrhages was compared when diets containing 30 or 40 per cent rapeseed meal (rsm) or 30 per cent soyabean meal (sbm),with and without experimental additives, were fed to in-lay hens of a commercial egg-producing strain for 12 weeks. The incidence of haemorrhages was significantly greater when the birds were maintained on the basal (unsupplemented) rsmdiet than on the equivalent sbmdiet. Haemorrhages were either small and infrequent, minute and multiple as in peliosis hepatis, or large enough to rupture the liver capsule. They might be recent or old and encapsulated, sometimes both varieties affecting the same specimen, and they occurred in any part of the liver. Histologically, hepatocyte necrosis and reticulin derangement were not detected in livers without gross haemorrhages and even in those with haemorrhages these abnormalities were only seen closely adjacent to haemorrhages or to foci of eosinophilic fibrinoid. In some instances there was sinusoidal ectasia. Separate additions of 50 g dried skimmed milk powder, 0·5 g zinc oxide, 0·25 g ferrous sulphate or 2·0 mg selenium (as sodium selenite) kg−1to the basal rsmdiet did not significantly modify the incidence of haemorrhage. Ferrous sulphate slightly reduced goitrogenicity. Supplements of 2·2 mg menadione and 1·0 g sodium phenobarbital kg−1rsmdiet induced slight reductions in the number of cases of liver haemorrhage or their severity, indicating that the multifunction oxidase system may be involved in rapeseed hepatotoxicity. The addition of 0·5 g methimazole kg−1to the basal sbmdiet induced severe colloid goitre but did not induce liver haemorrhage. Both thiouracil (0·5 g kg−1diet) and β-aminopropionitrile (0·5 g and 2·5 g kg−1diet) when added to the basal sbmdiet induced liver haemorrhages which did not differ in incidence or histological appearance from those induced by rsm.Hyperplastic goitre was caused by thiouracil. Intrahepatic cholestasis induced by sodium taurolithocholate, bilirubin and α-naphthylisothiocyanate and extrahepatic cholestasis induced by bile duct ligation resulted in hepatocyte necrosis but not gross liver haemorrhages. Spontaneous deaths due to conditions other than liver haemorrhages were significantly more numerous in rsm-fed than sbm-fed hens. Although histological evidence of reticulin damage was not detected, defects in collagen metabolism cannot be excluded at present because similar haemorrhages can be induced by a synthetic lathyrogen. As a goitrogen also induced haemorrhages and because a proportion of haemorrhages occur in birds on other diets, it is suggested that several factors including inherited, physiological and anatomical peculiarities of the in-lay hen combine with rapeseed toxins (perhaps including glucosinolate hydrolysis products) to induce a high incidence of liver haemorrhages.

A numerical model has been developed to simulate flow in rectangular clarifiers operating at neutral density conditions. The equations of motion in the ψ−ω format are solved using a finite‐difference method. A two‐step ADI three time level, weighted upwind‐centered difference scheme is used to solve the ω‐equation. The centered‐difference analog of the ψ‐equation is solved using the SOR method. A truncation convergence criterion was derived where the local Courant Number has to be kept below one. Computational stability depends on both Courant number and grid Reynolds number. A variable size mesh reduces both execution time and storage requirements without loss of solution accuracy. A partial slip boundary condition improves on the turbulence model. The finite difference and experimental flow fields are in good agreement.