Stock Characteristics of Humpback Whitefish and Least Cisco in the Chatanika River, Alaska

Overharvest of humpback whitefish (Coregonus pidschian) and least cisco (C. sardinella) in the Chatanika River, Alaska, during the late 1980s led to collapsed stocks and closure of the fishery. We evaluated the stock characteristics of these two species to determine the extent of recovery. A total of 3207 humpback whitefish and 2766 least cisco were captured during their fall spawning migration in 2008. Humpback whitefish ranged from 188 to 583 mm in fork length (FL) and encompassed ages 5 to 29 years, while least cisco ranged from 215 to 425 mm in FL and their ages ranged from 3 to 14 years. Patterns in growth and length-at-age were similar for both species, and annual mortality rates were 31% for humpback whitefish (age 11 and older) and 44% for least cisco (age 9 and older). Population attributes were within the ranges observed for other North American stocks of humpback whitefish and least cisco. Although the humpback whitefish in the Chatanika River have stock attributes that are consistent with low exploitation and this species appears to have recovered, the least cisco in the river still exhibit many attributes that suggest the cisco stock has not fully recovered. The results of this study indicate that the current allowable harvest limit of 2000 whitefish is cautious and appears to be sustainable.Vers la fin des années 1980, la pêche excessive du corégone à bosse (Coregonus pidschian) et de la cisco sardinelle (C. sardinella) dans la rivière Chatanika, en Alaska, a entraîné l’évidement des stocks et la fermeture du lieu de pêche. Nous avons évalué les caractéristiques des stocks de ces deux espèces afin de déterminer l’ampleur de leur rétablissement. Au total, 3 207 corégones à bosse et 2 766 ciscos sardinelles ont été capturés pendant leur frai de migration automnale en 2008. La longueur à la fourche du corégone à bosse variait entre 188 et 583 mm pour des âges allant de 5 à 29 ans, tandis que la longueur à la fourche de la cisco sardinelle variait entre 215 et 425 mm pour des âges allant de 3 à 14 ans. Les tendances de croissance et de longueur selon l’âge étaient semblables dans le cas des deux espèces, et les taux de mortalité annuels se chiffraient à 31 % dans le cas des corégones à bosse (âgés de 11 ou plus) et de 44 % pour les ciscos sardinelles (âgées de 9 ans et plus). Les caractéristiques de l’ensemble de la population se trouvaient dans les limites observées pour d’autres stocks nord-américains de corégones à bosse et de ciscos sardinelles. Bien que les caractéristiques du stock de corégone à bosse de la rivière Chatanika soient conformes à une faible exploitation et bien que cette espèce semble s’être rétablie, la cisco sardinelle de cette rivière affiche toujours de nombreuses caractéristiques qui laissent entendre que ce stock ne s’est pas encore complètement rétabli. Les résultats de cette étude indiquent que la limite actuelle de 2 000 qui est imposée quant à la pêche du corégone à bosse est prudente et semble durable

An experimental investigation of chatter effects on tool life

Tool wear is one of the most important considerations in machining operations as it affects surface quality and integrity, productivity and cost. The most commonly used model for tool life analysis is the one proposed by F.W. Taylor about a century ago. Although the extended form of this equation includes the effects of important cutting conditions on tool wear, tool life studies are mostly performed under stable cutting conditions where the effect of chatter vibrations are not considered. This paper presents an empirical attempt to understand tool life under vibratory cutting conditions. Tool wear data are collected in turning and milling on different work materials under stable and chatter conditions. The effects of cutting conditions as well as severity of chatter on tool life are analyzed. The results indicate significant reduction in tool life due to chatter as expected. They also show that the severity of chatter, and thus the vibration amplitude, strongly reduces the life of cutting tools. These results can be useful in evaluating the real cost of chatter by including the reduced tool life. They can also be useful in justifying the cost of chatter suppression and more rigid machining systems

Applied Force and sEMG Muscle Activity Required To Operate Pistol Grip Control in an Electric Utility Aerial Bucket

Electric utility line workers report high levels of fatigue in forearm muscles when operating a conventional pistol grip control in aerial buckets. This study measured the applied force and surface electromyographic (sEMG) signals from four upper extremity muscles required to operate the pistol grip control in two tasks. The first task was movement of the pistol grip in six directions (up/down, forward/rearward, clockwise/counter-clockwise), and the second task was movement of the bucket from its resting position on the truck bed to an overhead conductor on top of a 40 ft tall pole. The force applied to the pistol grip was measured in 14 aerial bucket trucks, and sEMG activity was measured on eight apprentice line workers. The applied force required to move the pistol grip control in the six directions ranged from 12 to 15 lb. The sEMG activity in the extensor digitorum communis (EDC) forearm muscle was approximately twice as great or more than the other three muscles (flexor digitorum superficialis, triceps, and biceps). Line workers exerted 14 to 30% MVCEMG to move the pistol grip in the six directions. Average %MVCEMG of the EDC to move the bucket from the truck platform to an overhead line ranged from 26 to 30% across the four phases of the task. The sEMG findings from this study provide physiologic evidence to support the anecdotal reports of muscle fatigue from line workers after using the pistol grip control for repeated, long durations

Light Microscopy Module (LMM)-Emulator

The Light Microscopy Module (LMM) is a microscope facility developed at Glenn Research Center (GRC) that provides researchers with powerful imaging capability onboard the International Space Station (ISS). LMM has the ability to have its hardware recongured on-orbit to accommodate a wide variety of investigations, with the capability of remotely acquiring and downloading digital images across multiple levels of magnication

Rapid detection, cloning and molecular cytogenetic characterisation of sequences from an MRP-encoding amplicon by chromosome microdissection.

Chromosome microdissection was utilised for the analysis of cytogenetic markers of gene amplification [homogeneously staining regions (hsrs) and double minutes (dmins)] in two doxorubicin-resistant cell lines, fibrosarcoma HT1080/DR4 and small-cell lung cancer H69AR. Microdissection products from the hsr(7)(p12p15) of HT1080/DR4 were amplified and used for fluorescent in situ hybridisation (micro-FISH) analysis of drug-sensitive HT1080, resistant HT1080/DR4 and normal lymphocytes. The results demonstrated that the hsr contains a domain of DNA amplification of complex origin including sequences derived from 16p11.2-16p13.1, 2q11.2, 7q32-7q34 and 10q22. The amplification was confirmed by converting the micro-dissected probe into a microclone library for probing HT1080 and HT1080/DR4 Southerns. A micro-FISH probe from normal band region 16p11-16p13 further demonstrated amplification of 16p sequences in both HT1080/DR4 and H69AR. During the course of this analysis, Cole et al. (1992) (Science, 258, 1650-1653) published the amplification of the MRP gene in H69AR cells, which maps to chromosome 16p13.1. Our results corroborate the finding of MRP amplification in these doxorubicin-resistant cell lines, but, importantly, they provide information on the composition of the complex amplicon contributions from four different chromosomes. This study demonstrates the potential utility of chromosome microdissection for the rapid recovery of sequences from amplified regions in drug-resistant cells

Developing Predictive Algorithm for Possible Fuel Stops for Private Aviation

Machine learning algorithms\u27 capacity to improve over time is one of their main advantages. When more and more data is handled, machine learning technology often becomes more effective and accurate. Machine learning can be used to address problems in industry. OneSky Flight is an aviation company under an umbrella of companies offering technology services for other private jet companies. One problem they face as a business is predicting when a flight will need a fuel stop upon a booking request. Given a data set of approximately 230,000 flights from OneSky, dating back to 2019, a prediction model will be made in order to achieve the overall objective of the project: a fuel stop predictor. Therefore, the customer is aware and can upgrade the aircraft or plan for the necessary fuel stop, saving the customer money and time

PIKES Analysis Reveals Response to Degraders and Key Regulatory Mechanisms of the CRL4 Network

Co-opting Cullin4 RING ubiquitin ligases (CRL4s) to inducibly degrade pathogenic proteins is emerging as a promising therapeutic strategy. Despite intense efforts to rationally design degrader molecules that co-opt CRL4s, much about the organization and regulation of these ligases remains elusive. Here, we establish protein interaction kinetics and estimation of stoichiometries (PIKES) analysis, a systematic proteomic profiling platform that integrates cellular engineering, affinity purification, chemical stabilization, and quantitative mass spectrometry to investigate the dynamics of interchangeable multiprotein complexes. Using PIKES, we show that ligase assemblies of Cullin4 with individual substrate receptors differ in abundance by up to 200-fold and that Cand1/2 act as substrate receptor exchange factors. Furthermore, degrader molecules can induce the assembly of their cognate CRL4, and higher expression of the associated substrate receptor enhances degrader potency. Beyond the CRL4 network, we show how PIKES can reveal systems level biochemistry for cellular protein networks important to drug development

Foam/aerogel composite materials for thermal and acoustic insulation and cryogen storage

The invention involves composite materials containing a polymer foam and an aerogel. The composite materials have improved thermal insulation ability, good acoustic insulation, and excellent physical mechanical properties. The composite materials can be used, for instance, for heat and acoustic insulation on aircraft, spacecraft, and maritime ships in place of currently used foam panels and other foam products. The materials of the invention can also be used in building construction with their combination of light weight, strength, elasticity, ability to be formed into desired shapes, and superior thermal and acoustic insulation power. The materials have also been found to have utility for storage of cryogens. A cryogenic liquid or gas, such as N.sub.2 or H.sub.2, adsorbs to the surfaces in aerogel particles. Thus, another embodiment of the invention provides a storage vessel for a cryogen