Large turbulent reservoirs of cold molecular gas around high-redshift starburst galaxies.

Starburst galaxies at the peak of cosmic star formation are among the most extreme star-forming engines in the Universe, producing stars over about 100 million years (ref. 2). The star-formation rates of these galaxies, which exceed 100 solar masses per year, require large reservoirs of cold molecular gas to be delivered to their cores, despite strong feedback from stars or active galactic nuclei. Consequently, starburst galaxies are ideal for studying the interplay between this feedback and the growth of a galaxy. The methylidyne cation, CH+, is a most useful molecule for such studies because it cannot form in cold gas without suprathermal energy input, so its presence indicates dissipation of mechanical energy or strong ultraviolet irradiation. Here we report the detection of CH+ (J = 1-0) emission and absorption lines in the spectra of six lensed starburst galaxies at redshifts near 2.5. This line has such a high critical density for excitation that it is emitted only in very dense gas, and is absorbed in low-density gas. We find that the CH+ emission lines, which are broader than 1,000 kilometres per second, originate in dense shock waves powered by hot galactic winds. The CH+ absorption lines reveal highly turbulent reservoirs of cool (about 100 kelvin), low-density gas, extending far (more than 10 kiloparsecs) outside the starburst galaxies (which have radii of less than 1 kiloparsec). We show that the galactic winds sustain turbulence in the 10-kiloparsec-scale environments of the galaxies, processing these environments into multiphase, gravitationally bound reservoirs. However, the mass outflow rates are found to be insufficient to balance the star-formation rates. Another mass input is therefore required for these reservoirs, which could be provided by ongoing mergers or cold-stream accretion. Our results suggest that galactic feedback, coupled jointly to turbulence and gravity, extends the starburst phase of a galaxy instead of quenching it.

Spatial distribution of FIR rotationally excited CH+ and OH emission lines in the Orion Bar PDR.

CONTEXT: The methylidyne cation (CH+) and hydroxyl (OH) are key molecules in the warm interstellar chemistry, but their formation and excitation mechanisms are not well understood. Their abundance and excitation are predicted to be enhanced by the presence of vibrationally excited H2 or hot gas (~500-1000 K) in photodissociation regions with high incident FUV radiation field. The excitation may also originate in dense gas (> 105 cm-3) followed by nonreactive collisions with H2, H, and electrons. Previous observations of the Orion Bar suggest that the rotationally excited CH+ and OH correlate with the excited CO, a tracer of dense and warm gas, and formation pumping contributes to CH+ excitation. AIMS: Our goal is to examine the spatial distribution of the rotationally excited CH+ and OH emission lines in the Orion Bar in order to establish their physical origin and main formation and excitation mechanisms. METHODS: We present spatially sampled maps of the CH+ J=3-2 transition at 119.8 µm and the OH Λ-doublet at 84 µm in the Orion Bar over an area of 110″×110″ with Herschel (PACS). We compare the spatial distribution of these molecules with those of their chemical precursors, C+, O and H2, and tracers of warm and dense gas (high-J CO). We assess the spatial variation of CH+ J=2-1 velocity-resolved line profile at 1669 GHz with Herschel HIFI spectrometer observations. RESULTS: The OH and especially CH+ lines correlate well with the high-J CO emission and delineate the warm and dense molecular region at the edge of the Bar. While notably similar, the differences in the CH+ and OH morphologies indicate that CH+ formation and excitation are strongly related to the observed vibrationally excited H2. This, together with the observed broad CH+ line widths, indicates that formation pumping contributes to the excitation of this reactive molecular ion. Interestingly, the peak of the rotationally excited OH 84 µm emission coincides with a bright young object, proplyd 244-440, which shows that OH can be an excellent tracer of UV-irradiated dense gas. CONCLUSIONS: The spatial distribution of CH+ and OH revealed in our maps is consistent with previous modeling studies. Both formation pumping and nonreactive collisions in a UV-irradiated dense gas are important CH+ J=3-2 excitation processes. The excitation of the OH Λ-doublet at 84 µm is mainly sensitive to the temperature and density.

Risks of nutrigenomics and nutrigenetics? What the scientists say.

Nutrigenomics and nutrigenetics (hereafter NGx) have stimulated expectations for beneficial applications in public health and individuals. Yet, the potential achievability of such promise is not without socioethical considerations that challenge NGx implementation. This paper focuses on the opinions of NGx researchers about potential risks raised by NGx. The results of an online survey show that these researchers (n = 126) are fairly confident about the potential benefits of NGx, and that most downplay its potential risks. Researchers in this field do not believe that NGx will reconfigure foods as medication or transform the conception of eating into a health hazard. The majority think that NGx will produce no added burden on individuals to get tested or to remain compliant with NGx recommendations, nor that NGx will threaten individual autonomy in daily food choice. The majority of researchers do not think that NGx will lead to discrimination against and/or stigmatization of people who do not comply with NGx dietary recommendations. Despite this optimism among NGx researchers, we suggest that key risk factors raised by the socioethical context in which NGx applications will be implemented need to be considered.

Benefits associated with nutrigenomics research and their reporting in the scientific literature: researchers' perspectives.

Nutrigenomics and nutrigenetics (NGx) are fields of research that have raised significant expectations about their potential benefits. This article presents empirical data from an online survey seeking the opinions of NGx researchers (n=126) regarding the achievability of the potential benefits of NGx, the time envisioned for their realization, the motives that may lead to their explicit mention in scientific peer-reviewed articles and the audience(s) targeted by NGx researchers when reporting their results in such articles. Results show that caution should be taken to avoid the risks associated with biohype and the premature dissemination of the potential benefits of NGx among various audiences.

Early patterning in a chondrichthyan model, the small spotted dogfish: towards the gnathostome ancestral state.

In the past few years, the small spotted dogfish has become the primary model for analyses of early development in chondrichthyans. Its phylogenetic position makes it an ideal outgroup to reconstruct the ancestral gnathostome state by comparisons with established vertebrate model organisms. It is also a suitable model to address the molecular bases of lineage-specific diversifications such as the rise of extraembryonic tissues, as it is endowed with a distinct extraembryonic yolk sac and yolk duct ensuring exchanges between the embryo and a large undivided vitelline mass. Experimental or functional approaches such as cell marking or in ovo pharmacological treatments are emerging in this species, but recent analyses of early development in this species have primarily concentrated on molecular descriptions. These data show the dogfish embryo exhibits early polarities reflecting the dorso-ventral axis of amphibians and teleosts at early blastula stages and an atypical anamniote molecular pattern during gastrulation, independently of the presence of extraembryonic tissues. They also highlight unexpected relationships with amniotes, with a strikingly similar Nodal-dependent regional pattern in the extraembryonic endoderm. In this species, extraembryonic cell fates seem to be determined by differential cell behaviors, which lead to cell allocation in extraembryonic and embryonic tissues, rather than by cell regional identity. We suggest that this may exemplify an early evolutionary step in the rise of extraembryonic tissues, possibly related to quantitative differences in the signaling activities, which shape the early embryo. These results highlight the conservation across gnathostomes of a highly constrained core genetic program controlling early patterning. This conservation may be obscured in some lineages by taxa-specific diversifications such as specializations of extraembryonic nutritive tissues.

Hydride spectroscopy of the diffuse interstellar medium: new clues on the gas fraction in molecular form and cosmic ray ionization rate in relation to H3+.

The Herschel-guaranteed time key programme PRobing InterStellar Molecules with Absorption line Studies (PRISMAS)(1) is providing a survey of the interstellar hydrides containing the elements C, O, N, F and Cl. As the building blocks of interstellar molecules, hydrides provide key information on their formation pathways. They can also be used as tracers of important physical and chemical properties of the interstellar gas that are difficult to measure otherwise. This paper presents an analysis of two sight-lines investigated by the PRISMAS project, towards the star-forming regions W49N and W51. By combining the information extracted from the detected spectral lines, we present an analysis of the physical properties of the diffuse interstellar gas, including the electron abundance, the fraction of gas in molecular form, and constraints on the cosmic ray ionization rate and the gas density.

[What tools should be used for follow-up post occupational exposure? What should be the frequency?]. / Quels outils doivent être utilisés pour le suivi post-professionnel ? Quel est le rythme de ce suivi ?

As long as the value of screening for cancers related to asbestos is not proven in the population at risk, the medical benefits of follow-up post-professional exposure remain uncertain and the only justification is to answer the questions of anxious retired workers concerning the consequences of their past-exposure and to provide compensation for any abnormalities that are demonstrated. In this country, to answer the questions posed in the title of this contribution in the case of pathologies related to asbestos, it is necessary, after verifying the fact and the level of exposure, to identify the pleural or pulmonary fibrosis and, above all, the pleural plaques, which constitute the essential lesions currently screened for. Thoracic CT scanning without contrast is the examination of choice to achieve this objective. There are, however, two significant problems. On one hand there is a high incidence of pulmonary micronodules, the necessary surveillance of which requires subsequent scans, leading to increased irradiation and anxiety. On the other hand the diagnostic uncertainty concerning discrete lesions is a source of confusion for the persons followed-up. There are, at present, neither scientific criteria to determine the optimum frequency of examination nor any arguments for replacing the pragmatic proposals of the consensus conference of 1999. It is important, therefore, to provide a medical assessment appropriate to the symptoms and anxiety expressed by a person previously exposed to asbestos. Overall it is necessary to question the benefit to the exposed person, in terms of quality of life, of a regular search for lesions that would usually be asymptomatic if not identified. Would it not be more judicious and more equitable to compensate persons whose past-exposure is sufficient to increase significantly their risk of cancer independently of the presence of benign abnormalities.

Inclusion and exclusion in nutrigenetics clinical research: ethical and scientific challenges.

BACKGROUND/AIMS: There are compelling reasons to ensure the participation of ethnic minorities and populations of all ages worldwide in nutrigenetics clinical research. If findings in such research are valid for some individuals, groups, or communities, and not for others, then ethical questions of justice--and not only issues of methodology and external validity--arise. This paper aims to examine inclusion in nutrigenetics clinical research and its scientific and ethical challenges. METHODS: In total, 173 publications were identified through a systematic review of clinical studies in nutrigenetics published between 1998 and 2007. Data such as participants' demographics as well as eligibility criteria were extracted. RESULTS: There is no consistency in the way participants' origins (ancestry, ethnicity, or race) and ages are described in publications. A vast majority of the studies identified was conducted in North America and Europe and focused on 'white' participants. Our results show that pregnant women (and fetuses), minors, and the elderly (≥ 75 years old) remain underrepresented. CONCLUSION: Representativeness in nutrigenetics research is a challenging ethical and scientific issue. Yet, if nutrigenetics is to benefit whole populations and be used in public and global health agendas, fair representation as well as clear descriptions of participants in publications are crucial.

Framing genomics, public health research and policy: points to consider.

Genetic information can be used to target interventions that improve health and prevent disease. Indeed, the results of population genomics research could be useful for public health and national pandemic plans. Yet, firm scientific evidence originating from such research and the indicators of the role of health determinants, gene-gene and gene-environment interaction remain to be assessed and validated before being integrated into pandemic plans or public health programmes. It is not clear what is the role of the State in research on the elucidation of the determinants of gene-gene and gene-environment interactions and how, when, and if such data can be accessed and used for such planning. Over a period of 3 years, we sought to address these questions by gathering data and literature relevant to research in public health genomics, preparing issues papers and, finally, consulting with stakeholders on a provisional 'points to consider' document at various times. Examining in turn the issues of privacy, State powers, stakeholder perceptions, and public participation, we propose in this article, for each of these themes, a series of recommendations aiming to provide guidance on the role of the State in the use of genomic information for public health research, prevention and planning.

Strategies for consulting with the community: the cases of four large-scale genetic databases.

Large-scale genetic databases are being developed in several countries around the world. However, these databases depend on public participation and acquiescence. In the past, information campaigns have been waged and little attention has been paid to dialogue. Nowadays, it is important to include the public in the development of scientific research and to encourage a free, open and useful dialogue among those involved. This paper is a review of community consultation strategies as part of four proposed large-scale genetic databases in Iceland, Estonia, United Kingdom and Quebec. The Iceland Health Sector Database and Estonian Genome Project have followed a "communication approach" in order to address public concerns, whereas, UK Biobank and Quebec CARTaGENE have chosen a "partnership approach" to involve the public in decision-making processes. Following a comparison of community consultation strategies, the main concerns of the public are examined as well as the challenges of involving communities. Importantly, reported across all groups is the concern for confidentiality, respect of the individual, transparency, and the donor's right to access to their own result. However, even if researchers demonstrate a willingness to respect values such as fair representation, transparency and accountability, there is still a risk that the public will mistrust researchers and simply will not participate in sufficient numbers. Complications may arise when individual and community interests conflicts. The implementation of a partnership approach is definitely involving and costly; however, if used properly, this method can improve both participation and so database development.

Risk factors for familial and sporadic ovarian cancer among French Canadians: a case-control study.

OBJECTIVE: The objective was to compare risk factors between familial and sporadic ovarian cancer by means of a case-control approach. STUDY DESIGN: We conducted a case-control study among French Canadian women in Montreal during 1995-1996. One hundred seventy women 20 to 84 years old with histologically confirmed diagnoses of primary ovarian carcinomas or borderline tumors were interviewed concerning their reproductive, family, and medical histories. During the same period 170 randomly selected population control subjects, frequency-matched to the case patients according to age and ethnic group, were also interviewed. Unconditional logistic regression methods were used for data analysis. RESULTS: The major factors influencing the risk of development of ovarian cancer were as follows: (1) family history of breast or ovarian cancer, (2) a late age at use of oral contraceptives (a protective effect), and (3) a late age at last childbirth (a protective effect for familial case patients only). CONCLUSION: These factors had equally great impacts in familial and sporadic cases, implying that the underlying mechanisms of carcinogenesis in sporadic and familial ovarian cancer may be similar and that hereditary ovarian cancer may be preventable.

Ethical issues involved in establishing a registry for familial Alzheimer's disease.

In January 1992, the IMAGE Project extended the establishment of its registry of familial Alzheimer cases to all areas of the province of Quebec, for collection of epidemiological and clinical data, as well as biological samples. The aim is to study genetic transmission patterns of Alzheimer's disease (AD) and to provide a sampling framework for further etiologic and risk factor studies. The IMAGE registry already includes data of a population-based study in the Saguenay-Lac-St-Jean area; the project to collect data on familial AD (FAD) cases across the province of Quebec is known as the ALGENE Initiative. The registry is thus a collection of "AD families" for both familial and sporadic cases. The establishment of the registry involves several steps in the field work: recruitment and selection of families; collection of information on family medical history; selection of informative families and genetic testing for AD/FAD by linkage analysis. As AD is not homogeneous in its etiology and since we do not know if, in the event that genetics is involved in AD whether or not penetrance of the gene(s) is high, we must be aware of the "genetic horizons" of AD in collecting and conserving data on families of cases, and in the genetic testing for AD/FAD by linkage analysis. Families who choose genetic testing must be aware of the implications of our undertaking, assured of the confidentiality of the test and, at the same time, they must understand its limitations. The experimental nature of our research project raises ethical dilemmas. This article examines these initial considerations of the field work involved in developing a registry pertaining to genetic testing for AD/FAD by linkage analysis and offers some preliminary observations on the experience of the first year of this project.

In situ double-beam NADH laser fluorimetry: choice of a reference wavelength.

A double-beam laser fluorimeter, using a single optical fiber to guide the lights, was constructed for in situ and on-line monitoring of NADH concentration [( NADH]) from normally blood-perfused living tissues. The device was tested on an isolated blood-perfused rat heart system to determine the most efficient reference wavelength for the compensation of the hemodynamic artifact induced by blood circulation in the tissues on the fluorescence measure; 586 nm was found to be an accurate reference wavelength, and a mathematical relationship was established that allowed the digital treatment of the measured fluorescence to give a signal (compensated fluorescence) that varied only with [NADH] in the volume of tissue investigated.