The gravitationally unstable gas disk of a starburst galaxy 12 billion years ago.

Galaxies in the early Universe that are bright at submillimetre wavelengths (submillimetre-bright galaxies) are forming stars at a rate roughly 1,000 times higher than the Milky Way. A large fraction of the new stars form in the central kiloparsec of the galaxy1-3, a region that is comparable in size to the massive, quiescent galaxies found at the peak of cosmic star-formation history4 and the cores of present-day giant elliptical galaxies. The physical and kinematic properties inside these compact starburst cores are poorly understood because probing them at relevant spatial scales requires extremely high angular resolution. Here we report observations with a linear resolution of 550 parsecs of gas and dust in an unlensed, submillimetre-bright galaxy at a redshift of z = 4.3, when the Universe was less than two billion years old. We resolve the spatial and kinematic structure of the molecular gas inside the heavily dust-obscured core and show that the underlying gas disk is clumpy and rotationally supported (that is, its rotation velocity is larger than the velocity dispersion). Our analysis of the molecular gas mass per unit area suggests that the starburst disk is gravitationally unstable, which implies that the self-gravity of the gas is stronger than the differential rotation of the disk and the internal pressure due to stellar-radiation feedback. As a result of the gravitational instability in the disk, the molecular gas would be consumed by star formation on a timescale of 100 million years, which is comparable to gas depletion times in merging starburst galaxies5.

The detection of a population of submillimeter-bright, strongly lensed galaxies.

Gravitational lensing is a powerful astrophysical and cosmological probe and is particularly valuable at submillimeter wavelengths for the study of the statistical and individual properties of dusty star-forming galaxies. However, the identification of gravitational lenses is often time-intensive, involving the sifting of large volumes of imaging or spectroscopic data to find few candidates. We used early data from the Herschel Astrophysical Terahertz Large Area Survey to demonstrate that wide-area submillimeter surveys can simply and easily detect strong gravitational lensing events, with close to 100% efficiency.

The formation of cluster elliptical galaxies as revealed by extensive star formation.

The most massive galaxies in the present-day Universe are found to lie in the centres of rich clusters. They have old, coeval stellar populations suggesting that the bulk of their stars must have formed at early epochs in spectacular starbursts, which should be luminous phenomena when observed at submillimetre wavelengths. The most popular model of galaxy formation predicts that these galaxies form in proto-clusters at high-density peaks in the early Universe. Such peaks are indicated by massive high-redshift radio galaxies. Here we report deep submillimetre mapping of seven high-redshift radio galaxies and their environments. These data confirm not only the presence of spatially extended regions of massive star-formation activity in the radio galaxies themselves, but also in companion objects previously undetected at any wavelength. The prevalence, orientation, and inferred masses of these submillimetre companion galaxies suggest that we are witnessing the synchronous formation of the most luminous elliptical galaxies found today at the centres of rich clusters of galaxies.

The Expert Consensus Guideline Series. Treatment of behavioral emergencies.

OBJECTIVES: Behavioral emergencies are a common and serious problem for consumers, their communities, and the healthcare settings on which they rely to contain, assess, and ultimately help the individual in a behavioral crisis. Partly because of the inherent dangers of this situation, there is little research to guide provider responses to this challenge. Key constructs such as agitation have not been adequately operationalized so that the criteria defining a behavioral emergency are vague. The significant progress that has been made for some disease states with better treatments and higher consumer acceptance has not penetrated this area of practice. A significant number of deaths of patients in restraint has focused government and regulators on these issues, but a consensus about key elements in the management of behavioral emergencies has not yet been articulated by the provider community. The authors assembled a panel of 50 experts to define the following elements: the threshold for emergency interventions, the scope of assessment for varying levels of urgency and cooperation, guiding principles in selecting interventions, and appropriate physical and medication strategies at different levels of diagnostic confidence and for a variety of etiologies and complicating conditions. METHOD: In order to identify issues in this area on which there is consensus, a written survey with 808 decision points was developed. The survey was mailed to a panel of 52 experts, 50 of whom completed it. A modified version of the RAND Corporation 9-point scale for rating appropriateness of medical decisions was used to score options. Consensus on each option was defined as a non-random distribution of scores by chi-square "goodness-of-fit" test. We assigned a categorical rank (first line/preferred choice, second line/alternate choice, third line/usually inappropriate) to each option based on the 95% confidence interval around the mean rating. Guideline tables were constructed describing the preferred strategies in key clinical situations. RESULTS: The expert panel reached consensus on 83% of the options. The relative appropriateness of emergency interventions was ascertained for a continuum of behaviors. When asked about the frequency with which emergency interventions (parenteral medication, restraints, seclusion) were required in their services, 47% of the experts reported that such interventions were necessary for 1%-5% of patients seen in their services and 32% for 6%-20%. In general, the consensus of this panel lends support to many elements of recent Health Care Financing Administration regulations, including the timing of clinician assessment and reassessment and the intensity of nursing care. However, the panel did not endorse the concept of "chemical restraint," instead favoring the idea that medications are treatments for target behaviors in behavioral emergencies even when the causes of these behaviors are not well understood. Control of aggressive behavior emerged as the highest priority during the emergency; however, preserving the physician-patient relationship was rated a close second and became the top priority in the long term. Oral medications, particularly concentrates, were clearly preferred if it is possible to use them. Benzodiazepines alone were top rated in 6 of 12 situations. High-potency conventional antipsychotics used alone never received higher ratings than benzodiazepines used alone. A combination of a benzodiazepine and an antipsychotic was preferred for patients with suspected schizophrenia, mania, or psychotic depression. There was equal support for high-potency conventional or atypical antipsychotics (particularly liquids) in oral combinations with benzodiazepines. Droperidol emerged in fourth place in some situations requiring an injection. CONCLUSIONS: To evaluate many of the treatment options in this survey, the experts had to extrapolate beyond controlled data in comparing modalities with each other or in combination. Within the limits of expert opinion and with the expectation that future research data will take precedence, these guidelines provide some direction for addressing common clinical dilemmas in the management of psychiatric emergencies and can be used to inform clinicians in acute care settings regarding the relative merits of various strategies.

Suicide in the medically and terminally ill: psychological and ethical considerations.

For the clinician who works in a behavioral-medicine or primary-care setting, this article presents the association between medical illness and suicide. Specific illnesses such as HIV/AIDS, cancers of the brain and nervous system, and multiple sclerosis all are associated with an increased risk of suicide. Rates of major depression rise with increasing rates of serious medical illness; however, depression and associated suicidal ideation tend to be undertreated in the medically ill. When medical illness becomes terminal, the clinician's patient may be confronted with difficult end-of-life decisions. Great concern exists in the United States about the ethics of end-of-life decision making and the issue of physician-assisted suicide. The latter part of this article examines the terminally ill patient's right to refuse life-sustaining treatments or to have death hastened according to the principle of the "double effect." It also reviews psychologists' apparent acceptance of the concept of rational suicide, as well as assisted suicide under certain conditions, and offers several caveats. A reexamination of psychology's role, standards, and principles with respect to rational suicide is recommended.

Suicide and violence assessment in psychiatry.

Psychiatrists are increasingly expected to predict and prevent the suicidal and violent/homicidal impulses of their clients. This article reviews the current literature and research in these areas. While the debate continues on whether the clinician can successfully predict either violence or suicidal behavior in their patients, the preponderance of studies weighs in that predicting suicide and violence in the individual may not be possible currently given present knowledge. To compensate for forecasting limitations, conservative clinicians deliberately overpredict suicide or violence to help insure the safety of their patients and the greater communities in which they reside. In addition, clinicians need to perform thorough assessments and make logical clinical decisions that are in line with the perceived risks. Preventive measures for violence remain complex, but clinicians can maximize treatment effects by following specific intervention guidelines. Minimally, documentation concerning violence needs to focus on the rationale for why treatment interventions were or were not implemented. The chart does not require lengthy notations but should include a reasonable assessment of risk and the delineation of a prudent course of action.

A scheme for classifying carcinogens.

We present a scheme for classifying chemical carcinogens according to the weight of the evidence that each substance poses a human cancer hazard. The approach represents a logical extension of and builds upon those previously developed by the International Agency for Research on Cancer, the U.S. Environmental Protection Agency, and the so-called Tripartite Group of industrial scientists. It takes into account new scientific knowledge about chemical carcinogenesis and animal models. Eight categories are presented: known human carcinogen (Category 1), carcinogenic activity in animals, probable human carcinogen (Category 2), possible human carcinogen (Category 3), equivocal evidence for carcinogenic activity (Category 4), evidence inadequate for classification (Category 5), carcinogenic activity in animals; probably not a human cancer hazard (Category 6), carcinogenic activity in animals; considered not a human cancer hazard (Category 7), evidence of noncarcinogenicity (Category 8). Evidence useful for categorization includes human studies, animal bioassays, corroborative evidence from bioassays, and mechanistic studies relevant to determining the predictivity of animal responses for human hazard. Weighing this evidence to derive a conclusion about classification is a process that requires expert judgment; it cannot now be reduced to a simple set of decision rules. However, we identify the kinds of information that can be useful in this process, and indicate how each might most appropriately be used.

An emergency psychiatry update.

A review of trends in emergency psychiatry since 1981 indicates that the scope and complexity of the field have greatly increased. Clinicians have found it useful to identify patient groups with special assessment and treatment needs, including adolescents, the elderly, victims of rape and of domestic violence, and repeat visitors to the emergency service. The spread of AIDS requires greater medical attentiveness by psychiatric emergency clinicians, and two recreational substances of abuse, cocaine and inhalants, have become increasingly popular. The use of psychotropic drugs in the emergency room has received more attention, and new trends in rapid tranquilization are apparent. Also reviewed are current medicolegal controversies related to emergency room practice, findings on prediction and control of violence, and the use of the psychiatric emergency service as a training site.