Differential involvement of Na(+),K(+)-ATPase isozymes in preimplantation development of the mouse.

Na(+),K(+)-ATPase plays an essential role in mammalian blastocoel formation (cavitation) by driving trans-epithelial sodium transport. Previously, the alpha1 and beta1 subunit isoforms of this enzyme were identified in preimplantation mouse embryos and were assumed to be responsible for this function. Here we show that mRNAs encoding an additional alpha subunit isoform (alpha3) and the remaining two beta subunit isoforms are also present in preimplantation embryos. Whereas alpha3 mRNA accumulates between the four-cell and the blastocyst stages and thus results from embryonic transcription, the same could not be demonstrated for beta2 and beta3 mRNAs. Immunoblot analyses confirmed that these subunits are present in cavitating embryos. Using confocal immunofluorescence microscopy we found that alpha1 and beta1 subunits are concentrated in the basolateral membranes of the trophectoderm while being equally distributed in plasma membranes of the inner cell mass. In contrast, alpha3, beta2, and beta3 subunits were not detected in plasma membranes. Our current assessment, therefore, is that as many as six isozymes of Na(+),K(+)-ATPase could be involved in preimplantation development although it is primarily the alpha1beta1 isozyme that is responsible for blastocoel formation. Our findings imply that the regulation of sodium transport within the preimplantation mouse embryo is more complex than had been appreciated

Optimization of double pulse pumping for Ni-like Sm x-ray lasers

We report a systematic study of double pulse pumping of the Ni-like Sm x-ray laser at 73 Angstrom, currently the shortest wavelength saturated x-ray laser. It is found that the Sm x-ray laser output can change by orders of magnitude when the intensity ratio of the pumping pulses and their relative delay are varied. Optimum pumping conditions are found and interpreted in terms of a simple model. (C) 1999 American Institute of Physics. [S0021-8979(99)07102-9]

Beluga Vocalizations Decrease in Response to Vessel Traffic in the Mackenzie River Estuary

Vessel traffic negatively affects marine mammals by causing behavioural disturbance, acoustic masking, contamination (i.e., oil spills), and ship strikes. Few studies have examined the effects of vessels on marine mammals in the Arctic, but beluga whales appear to be especially sensitive to vessel traffic. We examine how the vocalizations of belugas are impacted by vessel traffic in the Tarium Niryutait Marine Protected Area in the Mackenzie River estuary of the western Canadian Arctic. Between one and four acoustic recorders were deployed between June and August each year between 2015 and 2018 near the only shipping channel at this site. We examined beluga vocalizations from acoustic recordings over four summers and assessed how the distance to the nearest vessel passing the acoustic recorder affected the number of vocalizations. Beluga vocalizations within the range of the acoustic recorder decreased significantly when vessels were within 5 km of the acoustic recorder. This result suggests either that belugas are avoiding the vessel or that they reduce their vocalization in response to vessel traffic. Future work is needed to assess exactly how belugas are reacting to vessel traffic in this area and what the long-term consequences of these reactions are. Management measures for reducing these impacts must be carefully considered, especially since these vessels are very restricted in where they can travel, and many of the vessels are necessary for the livelihoods of local communities.La circulation maritime a des effets négatifs sur les mammifères marins, car elle entraîne des perturbations comportementales, masque leurs signaux acoustiques et engendre de la contamination (comme des déversements de pétrole) et des collisions. Bien que peu d’études aient examiné les effets des bateaux sur les mammifères marins de l’Arctique, les bélugas semblent particulièrement sensibles à la circulation maritime. Dans cet article, nous examinons en quoi les vocalisations des bélugas sont touchées par la circulation maritime dans la zone de protection marine de Tarium Niryutait faisant partie de l’estuaire du fleuve Mackenzie, dans l’ouest de l’Arctique canadien. Entre un et quatre enregistreurs acoustiques ont été déployés de juin à août de chaque année entre 2015 et 2018, à proximité du seul chenal de navigation de l’endroit. Nous avons examiné les vocalisations des bélugas prélevées à l’aide des enregistreurs acoustiques au cours de quatre étés, et évalué en quoi la distance du bateau passant le plus près de l’enregistreur acoustique avait un effet sur le nombre de vocalisations. Les vocalisations des bélugas dans la zone de l’enregistreur acoustique diminuaient considérablement lorsque les bateaux se trouvaient à moins de cinq kilomètres de l’enregistreur. Ce résultat suggère soit que les bélugas évitent les bateaux, soit qu’ils réduisent leurs vocalisations en réponse à la circulation maritime. Il y a lieu de pousser cette étude plus loin pour évaluer exactement comment les bélugas réagissent à la circulation des bateaux dans cette région, et quelles sont les conséquences à long terme de ces réactions. Il y a lieu aussi de considérer avec soin des mesures de gestion pour réduire ces incidences, surtout parce que les déplacements de ces bateaux sont assujettis à de nombreuses restrictions et parce que grand nombre des bateaux qui passent par là sont nécessaires à la subsistance des collectivités de la région. &nbsp

Supersonic strain front driven by a dense electron-hole plasma

We study coherent strain in (001) Ge generated by an ultrafast laser-initiated high density electron-hole plasma. The resultant coherent pulse is probed by time-resolved x-ray diffraction through changes in the anomalous transmission. The acoustic pulse front is driven by ambipolar diffusion of the electron-hole plasma and propagates into the crystal at supersonic speeds. Simulations of the strain including electron-phonon coupling, modified by carrier diffusion and Auger recombination, are in good agreement with the observed dynamics.Comment: 4 pages, 6 figure

A renal registry for Africa: first steps.

There is a dearth of data on end-stage renal disease (ESRD) in Africa. Several national renal registries have been established but have not been sustainable because of resource limitations. The African Association of Nephrology (AFRAN) and the African Paediatric Nephrology Association (AFPNA) recognize the importance of good registry data and plan to establish an African Renal Registry. This article reviews the elements needed for a successful renal registry and gives an overview of renal registries in developed and developing countries, with the emphasis on Africa. It then discusses the proposed African Renal Registry and the first steps towards its implementation. A registry requires a clear purpose, and agreement on inclusion and exclusion criteria, the dataset and the data dictionary. Ethical issues, data ownership and access, the dissemination of findings and funding must all be considered. Well-documented processes should guide data collection and ensure data quality. The ERA-EDTA Registry is the world's oldest renal registry. In Africa, registry data have been published mainly by North African countries, starting with Egypt and Tunisia in 1975. However, in recent years no African country has regularly reported national registry data. A shared renal registry would provide participating countries with a reliable technology platform and a common data dictionary to facilitate joint analyses and comparisons. In March 2015, AFRAN organized a registry workshop for African nephrologists and then took the decision to establish, for the first time, an African Renal Registry. In conclusion, African nephrologists have decided to establish a continental renal registry. This initiative could make a substantial impact on the practice of nephrology and the provision of services for adults and children with ESRD in many African countries

Exposure and behavioral responses of tagged beluga whales (Delphinapterus leucas) to ships in the Pacific Arctic

Arctic marine mammals face a multitude of challenges linked to climate change, including increasing anthropogenic noise from ship traffic. The beluga whale (Delphinapterus leucas), a predominately Arctic endemic cetacean, relies heavily on acoustic communication, with documented overlap between their vocalizations and hearing range and ship noise. Some belugas migrate through areas with the highest levels of ship traffic in the Pacific Arctic and exposure to ship noise is highly probable. Here, we document the responses of nine satellite-tagged Eastern Beaufort Sea belugas to encounters with ships in the Beaufort, Chukchi, and Bering Seas during July–December 2018. We report 177 occasions when ships were within 125 km of tagged belugas and quantified changes in lateral and vertical movements to investigate individual behavioral responses to ship approaches within 50 km (n = 23). Belugas\u27 swim speed was negatively correlated with ship distance, showing possible changes in swim speed up to 79 km away. Changes in lateral and vertical movements, indicating disruption of behavior, were observed when some ships passed within 50 km. These findings corroborate previous studies that have shown behavioral responses of belugas to ships at distances far beyond visual range, implying belugas react to low-amplitude ship noise near ambient levels

Lipoprotein-associated phospholipase A 2 , platelet-activating factor acetylhydrolase: a potential new risk factor for coronary artery disease

Abstract A specific and robust immunoassay for the lipoprotein-associated phospholipase A 2 (Lp-PLA 2 ), platelet-activating factor acetylhydrolase, is described for the first time. The immunoassay was used to evaluate possible links between plasma Lp-PLA 2 levels and atherosclerosis risk amongst susceptible individuals. Such an investigation was important because Lp-PLA 2 participates in the oxidative modification of low density lipoprotein by cleaving oxidised phosphatidylcholines, generating lysophosphatidylcholine and oxidised free fatty acids. The majority of Lp-PLA 2 was found associated with LDL (approximately 80%) and, as expected, enzyme levels were significantly positively correlated to LDL cholesterol. Plasma Lp-PLA 2 levels were significantly elevated in patients with angiographically proven coronary artery disease (CAD) when compared with age-matched controls, even though LDL cholesterol levels did not differ significantly. Indeed, when included in a general linear model with LDL cholesterol and other risk factors, Lp-PLA 2 appeared to be an independent predictor of disease status. We propose, therefore, that plasma Lp-PLA 2 mass should be viewed as a potential novel risk factor for CAD that provides information related to but additional to traditional lipoprotein measurements

Microbiome profiling by Illumina sequencing of combinatorial sequence-tagged PCR products

We developed a low-cost, high-throughput microbiome profiling method that uses combinatorial sequence tags attached to PCR primers that amplify the rRNA V6 region. Amplified PCR products are sequenced using an Illumina paired-end protocol to generate millions of overlapping reads. Combinatorial sequence tagging can be used to examine hundreds of samples with far fewer primers than is required when sequence tags are incorporated at only a single end. The number of reads generated permitted saturating or near-saturating analysis of samples of the vaginal microbiome. The large number of reads al- lowed an in-depth analysis of errors, and we found that PCR-induced errors composed the vast majority of non-organism derived species variants, an ob- servation that has significant implications for sequence clustering of similar high-throughput data. We show that the short reads are sufficient to assign organisms to the genus or species level in most cases. We suggest that this method will be useful for the deep sequencing of any short nucleotide region that is taxonomically informative; these include the V3, V5 regions of the bac- terial 16S rRNA genes and the eukaryotic V9 region that is gaining popularity for sampling protist diversity.Comment: 28 pages, 13 figure

Rethinking media responsibility in the refugee ‘crisis’: a visual typology of European news

In this paper, we analyse how news images of the 2015 Syrian refugee ‘crisis’ visualise refugees and how, in so doing, they mobilise various forms of moral responsibility in ‘our’ mediated public life – various practical dispositions of action towards the misfortunes of migrants and refugees at Europe’s border. On the basis of empirical material from European news (June-December 2015), we construct a typology of visibilities of the ‘crisis’, each of which situates refugees within a different regime of visibility and claim to action: i) visibility as biological life, associated with monitorial action; ii) visibility as empathy associated with charitable action; iii) visibility as threat, associated with state security; iv) visibility as hospitality, associated with political activism; and v) visibility as selfreflexivity, associated with a post-humanitarian engagement with people like ‘us’. In conclusion, we argue that, important as these five categories of visibility are in introducing public dispositions to action towards the vulnerable, they nonetheless ultimately fail to humanise migrants and refugees. This failure to portray them as human beings with lives that are worth sharing should compel us, we urge, to radically re-think how we understand the media’s responsibility towards vulnerable others