Fatty acid profiles of Alaskan Arctic forage fishes: evidence of regional and temporal variation

Thesis (M.S.) University of Alaska Fairbanks, 2015Fatty acids, the main components of lipids, are crucial for energy storage and other physiological functions in animals and plants. Dietary fatty acids are incorporated and conserved in consumer tissues in predictable patterns and can be analyzed in animal tissues to determine the composition of an individual's diet. This study measured the variation in fatty acid profiles of three abundant Arctic forage fish species, Arctic Cod (Boreogadus saida), Canadian Eelpout (Lycodes polaris), and Longear Eelpout (Lycodes seminudus) across multiple years (2010-2013) and geographic locations (Beaufort and Chukchi seas). These fishes are important prey items of marine mammals, sea birds, and predatory fishes, and as such they serve as a critical trophic step connecting lower trophic-level production to higher level predators. Analyzing forage fish fatty acid profiles across multiple years and geographic locations can provide insight into system-level trends in lipid transfer through the Arctic ecosystem. Fatty acid profiles differed among species, with Arctic Cod having higher concentrations of pelagic zooplankton indicator fatty acids, and Eelpout species containing higher concentrations of indicators for benthic prey. While the two Eelpout species displayed major overlap in fatty acid profiles, differences in individual fatty acids may represent niche separation between Canadian and Longear Eelpout in the Beaufort Sea. In addition to variation between species, fatty acid profiles also differed in Arctic Cod between the Beaufort and Chukchi seas, and among collection years. High lipid content and energy-rich fatty acid classes observed in Chukchi Sea Arctic Cod relative to the Beaufort Sea Arctic Cod may indicate favorable feeding conditions in this region over the years sampled, and high energy density of Arctic Cod as prey. Despite the within-species variation observed, the results of this study suggest that Alaskan Arctic forage fish with different foraging ecology can be distinguished based on fatty acid profile, which could be useful in studies that use fatty acid data to characterize diets of top predators

Self-supervised Speaker Diarization

Over the last few years, deep learning has grown in popularity for speaker verification, identification, and diarization. Inarguably, a significant part of this success is due to the demonstrated effectiveness of their speaker representations. These, however, are heavily dependent on large amounts of annotated data and can be sensitive to new domains. This study proposes an entirely unsupervised deep-learning model for speaker diarization. Specifically, the study focuses on generating high-quality neural speaker representations without any annotated data, as well as on estimating secondary hyperparameters of the model without annotations. The speaker embeddings are represented by an encoder trained in a self-supervised fashion using pairs of adjacent segments assumed to be of the same speaker. The trained encoder model is then used to self-generate pseudo-labels to subsequently train a similarity score between different segments of the same call using probabilistic linear discriminant analysis (PLDA) and further to learn a clustering stopping threshold. We compared our model to state-of-the-art unsupervised as well as supervised baselines on the CallHome benchmarks. According to empirical results, our approach outperforms unsupervised methods when only two speakers are present in the call, and is only slightly worse than recent supervised models.Comment: Submitted to Interspeech 202

Enhanced at puberty 1 (EAP1) is a new transcriptional regulator of the female neuroendocrine reproductive axis

The initiation of mammalian puberty and the maintenance of female reproductive cycles are events controlled by hypothalamic neurons that secrete the decapeptide gonadotropin-releasing hormone (GnRH). GnRH secretion is, in turn, controlled by changes in neuronal and glial inputs to GnRH-producing neurons. The hierarchical control of the process is unknown, but it requires coordinated regulation of these cell-cell interactions. Here we report the functional characterization of a gene (termed enhanced at puberty 1 [EAP1]) that appears to act as an upstream transcriptional regulator of neuronal networks controlling female reproductive function. EAP1 expression increased selectively at puberty in both the nonhuman primate and rodent hypothalamus. EAP1 encoded a nuclear protein expressed in neurons involved in the inhibitory and facilitatory control of reproduction. EAP1 transactivated genes required for reproductive function, such as GNRH1, and repressed inhibitory genes, such as preproenkephalin. It contained a RING finger domain of the C3HC4 subclass required for this dual transcriptional activity. Inhibition of EAP1 expression, targeted to the rodent hypothalamus via lentivirus-mediated delivery of EAP1 siRNAs, delayed puberty, disrupted estrous cyclicity, and resulted in ovarian abnormalities. These results suggest that EAP1 is a transcriptional regulator that, acting within the neuroendocrine brain, contributes to controlling female reproductive function.This work was supported by grants from the NIH, the National Institute of Child Health and Human Development/NIH (to S.R. Ojeda), the European Society for Paediatric Endocrinology (to H. Jung), the German Research Foundation (to S. Heger), and the European Commission (PIONEER to S. Heger)

A Systematic Review and Meta-Regression Analysis of Lung Cancer Risk and Inorganic Arsenic in Drinking Water.

High levels (\u3e 200 µg/L) of inorganic arsenic in drinking water are known to be a cause of human lung cancer, but the evidence at lower levels is uncertain. We have sought the epidemiological studies that have examined the dose-response relationship between arsenic levels in drinking water and the risk of lung cancer over a range that includes both high and low levels of arsenic. Regression analysis, based on six studies identified from an electronic search, examined the relationship between the log of the relative risk and the log of the arsenic exposure over a range of 1-1000 µg/L. The best-fitting continuous meta-regression model was sought and found to be a no-constant linear-quadratic analysis where both the risk and the exposure had been logarithmically transformed. This yielded both a statistically significant positive coefficient for the quadratic term and a statistically significant negative coefficient for the linear term. Sub-analyses by study design yielded results that were similar for both ecological studies and non-ecological studies. Statistically significant X-intercepts consistently found no increased level of risk at approximately 100-150 µg/L arsenic

The Lake Edgar Fault: an active fault in Southwestern Tasmania, Australia, with repeated displacement in the Quaternary

The Lake Edgar Fault in Western Tasmania, Australia is marked by a prominent fault scarp and is a recently reactivated fault initially of Cambrian age. The scarp has a northerly trend and passes through the western abutment of the Edgar Dam, a saddle dam on Lake Pedder. The active fault segment displaces geologically young river and glacial deposits. It is 29 ± 4 km long, and dips to the west. Movement on the fault has ruptured the ground surface at least twice within the Quaternary and possibly the last ca. 25 000 years; the most recent rupture has occurred since the last glaciation (within the last ca. 10000 years). This is the only known case of surface faulting in Australia with evidence for repeated ruptures in the Late Pleistocene. Along its central portion the two most recent surface-faulting earthquakes have resulted in about 2.5 m of vertical displacement each (western side up). The Lake Edgar Fault is considered capable of generating earthquakes in the order of magnitude 61/2-71/4. The Gell River Fault is another fault nearby that was apparently also active in the Late Pleistocene. It has yet to be studied in detail but the scarp appears to be more degraded and therefore older than the most recent movement on the Lake Edgar Fault

A 2000 yr paleoearthquake record along the Conway segment of the Hope fault : implications for patterns of earthquake occurrence in northern South Island and southern North Island, New Zealand

Paleoseismic trenches excavated at two sites reveal ages of late Holocene earthquakes along the Conway segment of the Hope fault, the fastest‐slipping fault within the Marlborough fault system in northern South Island, New Zealand. At the Green Burn East (GBE) site, a fault‐perpendicular trench exposed gravel colluvial wedges, fissure fills, and upward fault terminations associated with five paleo‐surface ruptures. Radiocarbon age constraints indicate that these five earthquakes occurred after 36 B.C.E., with the four most recent surface ruptures occurring during a relatively brief period (550 yr) between about 1290 C.E. and the beginning of the historical earthquake record about 1840 C.E. Additional trenches at the Green Burn West (GBW) site 1.4 km west of GBE reveal four likely coseismically generated landslides that occurred at approximately the same times as the four most recent GBE paleoearthquakes, independently overlapping with age ranges of events GB1, GB2, and GB3 from GBE. Combining age constraints from both trench sites indicates that the most recent event (GB1) occurred between 1731 and 1840 C.E., the penultimate event GB2 occurred between 1657 and 1797 C.E., GB3 occurred between 1495 and 1611 C.E., GB4 occurred between 1290 and 1420 C.E., and GB5 occurred between 36 B.C.E. and 1275 C.E. These new data facilitate comparisons with similar paleoearthquake records from other faults within the Alpine–Hope–Jordan–Kekerengu–Needles–Wairarapa (Al‐Hp‐JKN‐Wr) fault system of throughgoing, fast‐slip‐rate (⁠≥10  mm/yr⁠) reverse‐dextral faults that accommodate a majority of Pacific–Australia relative plate boundary motion. These comparisons indicate that combinations of the faults of the Al‐Hp‐JKN‐Wr system may commonly rupture within relatively brief, ≤100‐year‐long sequences, but that full “wall‐to‐wall” rupture sequences involving all faults in the system are rare over the span of our paleoearthquake data. Rather, the data suggest that the Al‐Hp‐JKN‐Wr system may commonly rupture in subsequences that do not involve the entire system, and potentially, at least sometimes, in isolated events

Late Quaternary faulting in the Kaikoura region, southeastern Marlborough, New Zealand

Active faults in the Kaikoura region include the Hope, Kekerengu, and Fidget Faults, and the newly discovered Jordan Thrust, Fyffe, and Kowhai Faults. Ages of faulted alluvial terraces along the Hope Fault and the Jordan Thrust were estimated using radiocarbon-calibrated weathering-rind measurements on graywacke clasts. Within the study area, the Hope Fault is divided, from west to east, into the Kahutara, Mt. Fyffe, and Seaward segments. The Kahutara segment has a relatively constant Holocene right-lateral slip rate of 20-32 mm/yr, and an earthquake recurrence interval of 86 to 600 yrs: based on single-event displacements of 3 to 12 m. The western portion of the Mt. Fyffe segment has a minimum Holocene lateral slip rate of 16 ± 5 mm/yr .(southeast side up); the eastern portion has horizontal and vertical slip rates of 4.8 ± 2.7 mm/yr and 1.7 ± 0.2 mm/yr, respectively (northwest side up). There is no dated evidence for late Quaternary movement on the Seaward segment, and its topographic expression is much more subdued than that of the two western segments. The Jordan Thrust extends northeast from the Hope Fault, west of the Seaward segment. The thrust has horizontal and vertical slip rates of 2.2 ± 1.3 mm/yr and 2.1 ± 0.5 mm/yr, respectively (northwest side up), and a maximum recurrence interval of 1200 yrs: based on 3 events within the last 3.5 ka. Drainage-divide elevation and mountain-front morphology of the Seaward Kaikoura Range, abundant evidence for recent activity on the Jordan Thrust, and lack of activity on the Seaward segment indicate that the late Quaternary displacement on the Hope Fault is transferred northward, west of the Seaward segment. The low slip rates for the thrust, compared to the higher lateral slip rates along the Kahutara and Mt. Fyffe segments, suggest that displacement on the Jordan Thrust does not accommodate all the displacement transferred from the Hope Fault. The remaining displacement is accommodated by distributed shear within the Torlesse rocks behind the thrust, and folds in front of and behind the thrust, although the latter was not documented for the Holocene

Molecular Regulation of Noradrenaline in Bovine Corpus Luteum

Noradrenergic stimulation increases progesterone, oxytocin and prostaglandins in the bovine luteal tissue. Better understanding of noradrenaline (NA) role in bovine the corpus luteum (CL) can advance our current knowledge on the regulatory mechanism of CL function. The present study was conducted to explore the source of noradrenaline and further to investigate whether nerve growth factor (NGF), insulin like growth factor 1 (IGF1) and transforming growth factor b1 (TGFb1) influence the expression of dopamine-b-hydroxylase (DBH), biosynthetic enzyme of NA in cultured bovine luteal cells. Corpora lutea were collected and classified into stages of early, developing, mid, late, and regressed. Messenger RNA (mRNA) and protein expression of DBH were studied throughout the estrous cycle. Additionally, DBH protein expression was examined in cultured mid luteal cells after tumour necrosis factor alpha/interferon gamma (TNFa/IFNg)-induced apoptosis or after treatment with NGF, IGF1, and TGFb1. DBH mRNA and protein expressions were detected throughout the cycle without significant changes in the protein level while mRNA showed a decrease at the developing stage (P < 0.05). Interestingly, NGF, IGF1, and TGFb1 increased DBH expression in cultured luteal cells (P < 0.05). The overall findings suggest non-neural source of noradrenaline in the bovine CL which appears to be regulated by NGF, IGF1, and TGFb1 indicating intraluteal molecules play an important and unrecognized role in the CL function

Molecular Cloning of the cDNA Encoding pp36, a Tyrosine-phosphorylated Adaptor Protein Selectively Expressed by T Cells and Natural Killer Cells

Activation of T and natural killer (NK) cells leads to the tyrosine phosphorylation of pp36 and to its association with several signaling molecules, including phospholipase Cγ-1 and Grb2. Microsequencing of peptides derived from purified rat pp36 protein led to the cloning, in rat and man, of cDNA encoding a T- and NK cell–specific protein with several putative Src homology 2 domain–binding motifs. A rabbit antiserum directed against a peptide sequence from the cloned rat molecule recognized tyrosine phosphorylated pp36 from pervanadate-treated rat thymocytes. When expressed in 293T human fibroblast cells and tyrosine-phosphorylated, pp36 associated with phospholipase Cγ-1 and Grb2. Studies with GST–Grb2 fusion proteins demonstrated that the association was specific for the Src homology 2 domain of Grb-2. Molecular cloning of the gene encoding pp36 should facilitate studies examining the role of this adaptor protein in proximal signaling events during T and NK cell activation

Arsenic in Drinking Water and Lung Cancer Mortality in the United States: An Analysis Based on US Counties and 30 Years of Observation (1950-1979).

Background. To examine whether the US EPA (2010) lung cancer risk estimate derived from the high arsenic exposures (10-934 µg/L) in southwest Taiwan accurately predicts the US experience from low arsenic exposures (3-59 µg/L). Methods. Analyses have been limited to US counties solely dependent on underground sources for their drinking water supply with median arsenic levels of ≥3 µg/L. Results. Cancer risks (slopes) were found to be indistinguishable from zero for males and females. The addition of arsenic level did not significantly increase the explanatory power of the models. Stratified, or categorical, analysis yielded relative risks that hover about 1.00. The unit risk estimates were nonpositive and not significantly different from zero, and the maximum (95% UCL) unit risk estimates for lung cancer were lower than those in US EPA (2010). Conclusions. These data do not demonstrate an increased risk of lung cancer associated with median drinking water arsenic levels in the range of 3-59 µg/L. The upper-bound estimates of the risks are lower than the risks predicted from the SW Taiwan data and do not support those predictions. These results are consistent with a recent metaregression that indicated no increased lung cancer risk for arsenic exposures below 100-150 µg/L