Analysis of Arctic Cod Movements in the Beaufort Sea Nearshore Region, 1978-79

A study was conducted to investigate distribution and abundance of arctic cod in the nearshore region of the Beaufort Sea. Data collection methods included 3 m otter trawl and hydroacoustic surveys. Temperature and conductivity measurements were taken throughout the study area on a regular basis. The results indicated that arctic cod are associated with a transition layer between a surface water mass, characterized by low salinity and high temperature, and a bottom water mass, characterized by high salinity and low temperature. Arctic cod apparently oriented to the shoreward edge of the marine water mass and redistributed themselves depending on the location of the shoreward edge. It is hypothesized that the transition layer concentrates food organisms, and this abundance of food may be one factor that induces shoals of arctic cod to utilize this transition layer.Key words: arctic cod, Alaskan Beaufort Sea, nearshore movements, temperature/salinity association, coastal habitat use, Boreogadus saida Une étude a été menée afin de déterminer la distribution et l'abondance de la morue arctique dans la zone côtière de la mer de Beaufort. Les données ont été recueillies à l'aide d'un chalut à plateaux de 3 m et de relevés hydro-acoustiques. Des mesures de température et de conductivité ont été prises de façon régulière, dans toute la zone étudiée. Les résultats ont indiqué que la morue arctique est associée à une couche de transition entre une masse d'eau de surface, caractérisée par une faible salinité et une haute température, et une masse d'eau profonde, caractérisée par une forte salinité et une basse température. La morue arctique se dirigeait apparemment vers la limite côtière de la masse d'eau de mer et sa distribution suivait cette limite côtière. On peut avancer l'hypothèse que la couche de transition est très riche en éléments nutritifs, et que cette abondance de nourriture est un des facteurs qui amènent les bancs de morues arctiques à se servir de cette couche de transition. Mots clés : morue arctique, mer de Beaufort de l'Alaska, déplacements près des côtes, association température/salinité, utilisation de l'habitat côtier, Boreogadus said

History of an Under-Ice Subsistence Fishery for Arctic Cisco and Least Cisco in the Colville River, Alaska

Arctic cisco (Coregonus autumnalis) and least cisco (C. sardinella) are harvested in the Colville River Delta near Nuiqsut, Alaska, after ice forms in the fall. Arctic cisco targeted by the fall fishery derive from spawning stocks in the Mackenzie River of Canada. Young-of-the-year fish are recruited into the Colville region during August or September, aided by westerly coastal currents generated by predominantly easterly winds. In contrast, anadromous least cisco, harvested as the primary by-catch in the fishery, spawn and winter entirely in the Colville delta and lower river. This study reports on fishery monitoring for the 20-year period 1985 – 2004. During this period, effort in the subsistence fishery showed an increasing trend. Arctic cisco, the target species, averaged over 65% of the annual observed catch, and least cisco averaged 22%. From 1985 to 2002, total harvest of arctic cisco for the combined subsistence and commercial fisheries averaged 38 600 fish (15 958 kg) per year, ranging from a low of 5859 fish (2799 kg) in 2001 to 78 254 fish (31 340 kg) in 1993. During the same period, catches of least cisco averaged 18 600 fish (5819 kg), ranging from a low of 6606 fish (2014 kg) in 2001 to 33 410 fish (11 319 kg) in 1985. The subsistence fishery caught 56% of the total arctic cisco harvest and 42% of the least cisco harvest (in numbers of fish). In the six years for which estimates of both harvest and population level were available, total estimated annual harvest of arctic cisco within the Colville River Delta averaged 8.9% of the available fish, with yearly estimates ranging from 5.4% to 12.9%. For least cisco, the average annual removal rate was 6.8% (range: 2.9% to 13.8%).Le cisco arctique (Coregonus autumnalis) et le cisco sardinelle (C. sardinella) sont pêchés dans le delta de la rivière Colville près de Nuiqsut, en Alaska, après la formation de la glace à l’automne. Les ciscos arctiques qui font l’objet de cette pêche d’automne proviennent de la fraie du fleuve Mackenzie au Canada. Les jeunes poissons de l’année sont recrutés dans la région de Colville en août ou en septembre, et sont aidés par les courants côtiers d’ouest générés par les vents principalement de l’est. Pour leur part, les ciscos sardinelles anadromes, qui sont récoltés en tant que prise fortuite principale de la pêche, fraient et hivernent entièrement dans le détroit Colville et la rivière inférieure. La présente étude fait état d’un projet de surveillance des pêches échelonné sur une période de 20 ans, soit de 1985 à 2004. Au cours de cette période, la pêche de subsistance a affiché une tendance à la hausse. Le cisco arctique, soit l’espèce ciblée, représentait en moyenne plus de 65 % de la prise annuelle observée, tandis que le cisco sardinelle représentait 22 % en moyenne. De 1985 à 2002, la récolte totale de cisco arctique pour l’ensemble de la pêche de subsistance et de la pêche commerciale a atteint, en moyenne, 38 600 poissons (15 958 kg) par année, allant du faible nombre de 5 859 poissons (2 799 kg) en 2001 à 78 254 poissons (31 340 kg) en 1993. Au cours de cette même période, les prises de ciscos sardinelles ont atteint, en moyenne, 18 600 poissons (5 819 kg), allant du faible nombre de 6 606 poissons (2 014 kg) en 2001 à 33 410 poissons (11 319 kg) en 1985. La pêche de subsistance a permis de récolter 56 % de tous les ciscos arctiques capturés et 42 % des ciscos sardinelles (pour ce qui est du nombre de poissons). Dans le cas des six années pour lesquelles il existe des estimations du taux de capture et de population, la capture annuelle totale estimée de ciscos arctiques dans le delta de la rivière Colville a atteint, en moyenne, 8,9 % des poissons disponibles, et les estimations annuelles s’échelonnaient entre 5,4 % à 12,9 %. Dans le cas du cisco sardinelle, le taux moyen annuel de prise s’élevait à 6,8 % (avec une étendue de 2,9 % à 13,8 %)

Stabilization and Localization of Xist RNA are Controlled by Separate Mechanisms and are Not Sufficient for X Inactivation

These studies address whether XIST RNA is properly localized to the X chromosome in somatic cells where human XIST expression is reactivated, but fails to result in X inactivation (Tinker, A.V., and C.J. Brown. 1998. Nucl. Acids Res. 26:2935–2940). Despite a nuclear RNA accumulation of normal abundance and stability, XIST RNA does not localize in reactivants or in naturally inactive human X chromosomes in mouse/ human hybrid cells. The XIST transcripts are fully stabilized despite their inability to localize, and hence XIST RNA localization can be uncoupled from stabilization, indicating that these are separate steps controlled by distinct mechanisms. Mouse Xist RNA tightly localized to an active X chromosome, demonstrating for the first time that the active X chromosome in somatic cells is competent to associate with Xist RNA. These results imply that species-specific factors, present even in mature, somatic cells that do not normally express Xist, are necessary for localization. When Xist RNA is properly localized to an active mouse X chromosome, X inactivation does not result. Therefore, there is not a strict correlation between Xist localization and chromatin inactivation. Moreover, expression, stabilization, and localization of Xist RNA are not sufficient for X inactivation. We hypothesize that chromosomal association of XIST RNA may initiate subsequent developmental events required to enact transcriptional silencing

Latency and time-dependent exposure in a case-control study

Detailed historical data are elicited often from subjects in retrospective studies, yielding time-dependent measures of exposures. Investigation of a hypothesized period of latency can be made by examining disease/exposure relationships in multiple time windows, either along the age or time-before diagnosis axes. We suggest splitting the data into many time intervals and separately fitting regression models tothe available data in each interval. Covariances between estimated coefficients from different intervals are empirically estimated, and used for assessing variability of specified functions of the time-specific coefficients. Alternative methods of interval formation and their consequences are discussed. We apply these methods to a French case-control study of oral contraceptive use and cervical cancer incidence, and compare the results to those of standard analyses.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29651/1/0000740.pd

Parametric frailty models for clustered data with arbitrary censoring: application to effect of male circumcision on HPV clearance

Background In epidemiological studies, subjects are often followed for a period during which study outcomes are measured at selected time points, such as by diagnostic testing performed on biological samples collected at each visit. Although test results may indicate the presence or absence of a disease or condition, they cannot provide information on when exactly it occurred. Such study designs generate arbitrarily censored time-to-event data, which can include left, interval and right censoring. Adding to this complexity, the data may be clustered such that observations within the same cluster are not independent, such as time to recovery of an infectious disease of family or community members. This data structure is observed when evaluating circumcision\u27s effect on clearance of penile high risk human papillomavirus (HR-HPV) infections using data collected from the male circumcision(MC) trial conducted in Rakai, Uganda, where the multiple infections within individual and HPV testings performed at trial follow-up visits gave rise to the clustered data with arbitrary censoring. Methods We describe the use of parametric proportional hazards frailty models and accelerated failure time frailty models to examine the relationship between explanatory variables and the survival outcomes that are subject to arbitrary censoring, while accounting for the correlation within clusters. Standard software such as SAS can be used for parameter estimation. Results Circumcision\u27s effect on HPV infection was a secondary end point in the Rakai MC trial, and HPV genotyping was conducted for penile samples of a subset of trial participants collected at enrollment, 6, 12 and 24-month follow up visits. At enrollment, 36.7% intervention arm men (immediate circumcision) and 36.6% control arm men (delayed circumcision at 2 years) were infected with HR-HPV, with the number of infections per man being 1-5. The proposed models were used to examine whether MC facilitated clearance of the prevalent infections. Results show that clearance of multiple infections within each man is highly correlated, and clearance was 60% faster if a man was circumcised. Conclusions Parametric frailty models provide viable ways to study the relationship between exposure variables and clustered survival outcome that is subject to arbitrary censoring, as is often observed in HPV epidemiology studies

A screen for nuclear transcripts identifies two linked noncoding RNAs associated with SC35 splicing domains

BACKGROUND: Noncoding RNA species play a diverse set of roles in the eukaryotic cell. While much recent attention has focused on smaller RNA species, larger noncoding transcripts are also thought to be highly abundant in mammalian cells. To search for large noncoding RNAs that might control gene expression or mRNA metabolism, we used Affymetrix expression arrays to identify polyadenylated RNA transcripts displaying nuclear enrichment. RESULTS: This screen identified no more than three transcripts; XIST, and two unique noncoding nuclear enriched abundant transcripts (NEAT) RNAs strikingly located less than 70 kb apart on human chromosome 11: NEAT1, a noncoding RNA from the locus encoding for TncRNA, and NEAT2 (also known as MALAT-1). While the two NEAT transcripts share no significant homology with each other, each is conserved within the mammalian lineage, suggesting significant function for these noncoding RNAs. NEAT2 is extraordinarily well conserved for a noncoding RNA, more so than even XIST. Bioinformatic analyses of publicly available mouse transcriptome data support our findings from human cells as they confirm that the murine homologs of these noncoding RNAs are also nuclear enriched. RNA FISH analyses suggest that these noncoding RNAs function in mRNA metabolism as they demonstrate an intimate association of these RNA species with SC35 nuclear speckles in both human and mouse cells. These studies show that one of these transcripts, NEAT1 localizes to the periphery of such domains, whereas the neighboring transcript, NEAT2, is part of the long-sought polyadenylated component of nuclear speckles. CONCLUSION: Our genome-wide screens in two mammalian species reveal no more than three abundant large non-coding polyadenylated RNAs in the nucleus; the canonical large noncoding RNA XIST and NEAT1 and NEAT2. The function of these noncoding RNAs in mRNA metabolism is suggested by their high levels of conservation and their intimate association with SC35 splicing domains in multiple mammalian species

Alcohol and traffic safety: A sensitivity analysis of data from composite sources

Risk factors associated with single-vehicle driver fatalities are explored in a sensitivity analysis of data from composite sources. Information on fatalities was taken from the Federal Accident Reporting System data base for 1976-1981. Characteristics of the driving population were given by the 1973 National Roadside Breath Testing Survey (Wolfe 1974). Using Bayes theorem and logistic regression analysis, the effect of changing driver characteristics on the probability of a fatality was explored. The method used is proposed for a case-control study in which the controls may not accurately represent the population from which the cases were drawn. Risk factors identified are generally in agreement with previous reports.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28061/1/0000500.pd

Bartlett correction factors in logistic regression models

Bartlett correction factors for likelihood ratio tests of parameters in conditional and unconditional logistic regression models are calculated. The resulting tests are compared to the Wald, likelihood ratio, and score tests, and a test proposed by Moolgavkar and Venzon in Modern Statistical Methods in Chronic Disease Epidemiology. (Wiley, New York, 1986).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31011/1/0000686.pd

Risk factors and case management of acute diarrhoea in North Gondar zone, Ethiopia

In Ethiopia, evidence is lacking about maternal care-taking and environmental risk factors that contribute to acute diarrhoea and the case management of diarrhoea. The aim of this study was to identify the risk factors and to understand the management of acute diarrhoea. A pretested structured questionnaire was used for interviewing mothers of 440 children in a prospective, matched, case-control study at the University of Gondar Referral and Teaching Hospital in Gondar, Ethiopia. Results of multivariate analysis demonstrated that children who were breastfed and not completely weaned and mothers who were farmers were protective factors; risk factors for diarrhoea included sharing drinking-water and introducing supplemental foods. Children presented with acute diarrhoea for 3.9 days with 4.3 stools per day. Mothers usually did not increase breastmilk and other fluids during diarrhoea episodes and generally did not take children with diarrhoea to traditional healers. Incorporating messages about the prevention and treatment of acute diarrhoea into child-health interventions will help reduce morbidity and mortality associated with this disease