Total mercury, methylmercury, and selenium concentrations in blue marlin Makaira nigricans from a long-term dataset in the western north Atlantic.

Mercury in seafood is a neurotoxicant that threatens human health. Dynamic rates of mercury emission, re-emission, and atmospheric deposition warrant studies into mercury concentrations in fish because many are consumed by humans and can serve as sentinels of mercury levels in the environment. We modeled trends in total mercury content in an apex marine fish predator, Atlantic blue marlin Makaira nigricans, whose muscle tissues were opportunistically sampled from North Carolina (USA) sportfishing tournaments over a discontinuous time period: between 1975 and 77 and 1998-2021 (n = 148). The model-estimated influence of marlin weight on total mercury concentration was constant across years (shared slope) allowing for comparisons of weight-corrected mercury concentrations among years. Weight-corrected total mercury concentrations revealed an inter-decadal decline of approximately 45 % between the 1970s and late 1990s and then variable but relatively stable concentrations through 2021. The mean (SD) wet weight concentration of total mercury was 9.47 (4.11) from 1975 to 77 and 4.17 (2.61) from 2020 to 2021. Methylmercury and selenium were measured on a subset of fish to address questions related to human health and consumption. Methylmercury levels (mean = 0.72 µg/g) were much lower than total mercury (mean = 4.69 µg/g) indicating that total mercury is not a good proxy for methylmercury in Atlantic blue marlin. Selenium, examined as a Se:Hg molar ratio and as a selenium health benefit value (HBVSe), showed high protective value against mercury toxicity. Long-term trends in the concentration of mercury in blue marlin should continue to be monitored to determine whether policies to mitigate anthropogenic contributions to global mercury are achieving their intended goals and to provide information to inform safe human consumption.

A dynamically young and perturbed Milky Way disk.

The evolution of the Milky Way disk, which contains most of the stars in the Galaxy, is affected by several phenomena. For example, the bar and the spiral arms of the Milky Way induce radial migration of stars1 and can trap or scatter stars close to orbital resonances2. External perturbations from satellite galaxies can also have a role, causing dynamical heating of the Galaxy3, ring-like structures in the disk4 and correlations between different components of the stellar velocity5. These perturbations can also cause 'phase wrapping' signatures in the disk6-9, such as arched velocity structures in the motions of stars in the Galactic plane. Some manifestations of these dynamical processes have already been detected, including kinematic substructure in samples of nearby stars10-12, density asymmetries and velocities across the Galactic disk that differ from the axisymmetric and equilibrium expectations13, especially in the vertical direction11,14-16, and signatures of incomplete phase mixing in the disk7,12,17,18. Here we report an analysis of the motions of six million stars in the Milky Way disk. We show that the phase-space distribution contains different substructures with various morphologies, such as snail shells and ridges, when spatial and velocity coordinates are combined. We infer that the disk must have been perturbed between 300 million and 900 million years ago, consistent with estimates of the previous pericentric passage of the Sagittarius dwarf galaxy. Our findings show that the Galactic disk is dynamically young and that modelling it as time-independent and axisymmetric is incorrect.

Recent status of total mercury and methyl mercury in the coastal waters of the northern Gulf of Mexico using oysters and sediments from NOAA's mussel watch program.

The current status of mercury concentrations in the Gulf of Mexico (GOM) were assessed using the Mussel Watch Program (MWP) contaminant monitoring data, which is based on the analysis of oyster tissue and sediment samples. In both matrices, tHg and MeHg concentrations varied broadly. Significant concentration differences (p<0.05) between the sub-regions of the eastern, central and western Gulf were observed with maximum concentrations (hotspots) found at specific sites all across the Gulf. Compared to the Food and Drug Administration's action level in seafood, maximum mercury values were low. Based on the long-term MWP data, tHg in tissues show fairly static temporal trends along the central and western Gulf coast, while strong decreasing trends were observed in the eastern Gulf. However, the presence of mercury hotspots indicates that mercury is still a concern in the GOM. The results complement existing information to further the understanding of mercury distributions in the GOM.

Repetitive and ritualistic behaviour in children with Prader-Willi syndrome and children with autism.

BACKGROUND: Recent research has shown that the range of repetitive behaviour seen in individuals with Prader-Willi syndrome (PWS) extends beyond food-related behaviour. METHODS: The presence and intensity of repetitive, rigid and routinized behaviour in children with PWS was compared with that seen in children with another neurodevelopmental condition in which repetitive behaviour is common: children with autism. Parents completed the Childhood Routines Inventory (CRI). RESULTS: Contrary to our predictions, controlling for developmental level, children with PWS and children with autism showed similar levels of repetitive and ritualistic behaviour overall and on the two CRI factors measuring 'just right' and 'repetitive' behaviour. Indeed, the majority of the sample of parents of children with PWS endorsed most items on the CRI. However there was some specificity at the level of individual items with parents of children with PWS more frequently endorsing an item on 'collecting and storing objects' and parents of children with autism more frequently endorsing 'lining up objects', 'has a strong preference for certain foods' and 'seems aware of detail at home'. CONCLUSIONS: These findings confirm the range of repetitive behaviours that form part of the behavioural phenotype of PWS, including insistence on sameness and 'just right' behaviours, and uncover a surprising overlap with those seen in children with autism. Clinical management for children with PWS should include advice and education regarding management of repetitive and rigid behaviour. Future research should investigate whether the repetitive behaviours that form part of the behavioural phenotype of both PWS and autism are associated with a common neuropsychological, neurotransmitter or genetic origin.

Does it matter that organ donors are not dead? Ethical and policy implications.

The "standard position" on organ donation is that the donor must be dead in order for vital organs to be removed, a position with which we agree. Recently, Robert Truog and Walter Robinson have argued that (1) brain death is not death, and (2) even though "brain dead" patients are not dead, it is morally acceptable to remove vital organs from those patients. We accept and defend their claim that brain death is not death, and we argue against both the US "whole brain" criterion and the UK "brain stem" criterion. Then we answer their arguments in favour of removing vital organs from "brain dead" and other classes of comatose patients. We dispute their claim that the removal of vital organs is morally equivalent to "letting nature take its course", arguing that, unlike "allowing to die", it is the removal of vital organs that kills the patient, not his or her disease or injury. Then, we argue that removing vital organs from living patients is immoral and contrary to the nature of medical practice. Finally, we offer practical suggestions for changing public policy on organ transplantation.

Contrast sensitivity improves after brimonidine therapy in primary open angle glaucoma: a case for neuroprotection.

AIMS: To determine the visual outcome following initiation of brimonidine therapy in glaucoma. METHODS: 16 newly diagnosed previously untreated glaucoma patients were randomly assigned to either timolol 0.5% or brimonidine 0.2%. Visual acuity, contrast sensitivity (CS), visual fields, intraocular pressure (IOP), blood pressure, and heart rate were evaluated at baseline and after 3 months. RESULTS: IOP reduction was similar for both groups (p<0.05). Brimonidine improved CS; in the right eye at 6 and 12 cpd (p=0.043, p=0.017); in the left eye at 3 and 12 cpd (p=0.044, p=0.046). Timolol reduced CS at 18 cpd in the right eye (p=0.041). There was no change in any other measured parameters. CONCLUSION: Glaucoma patients exhibit improved CS on initiation of brimonidine therapy.

Hypercapnia invokes an acute loss of contrast sensitivity in untreated glaucoma patients.

BACKGROUND/AIM: It is widely accepted that hypercapnia results in increased retinal, choroidal, and retrobulbar blood flow. Reports of a visual response to hypercapnia appear mixed, with normal subjects exhibiting reduced temporal contrast sensitivity in some studies, while glaucoma patients demonstrate mid-peripheral visual field improvements in others. This suggests that under hypercapnic conditions a balance exists between the beneficial effects of improved ocular blood flow and some other factor such as induced metabolic stress; the outcome may be influenced by the disease process. The aim of this study was to evaluate the contrast sensitivity response of untreated glaucoma patients and normal subjects during mild hypercapnia. METHODS: 10 previously untreated glaucoma patients and 10 control subjects were evaluated for contrast sensitivity and intraocular pressure while breathing room air and then again during mild hypercapnia. RESULTS: During room air breathing, compared with normal subjects, glaucoma patients had higher IOP (p = 0.0003) and lower contrast sensitivity at 3 cycles/degree (cpd) (p = 0.001). Mild hypercapnia caused a significant fall in contrast sensitivity at 6, 12, and 18 cpd (p < 0.05), only in the glaucoma group. CONCLUSION: Glaucoma patients with early disease exhibit central vision deficits as shown by contrast sensitivity testing at 3 cpd. Hypercapnia induces further contrast loss through a range of spatial frequencies (6-18 cpd) which may be predictive of further neuronal damage due to glaucoma.

Ego development, self-perception, and self-complexity in adolescence: a study of female psychiatric inpatients.

A study of two groups of female psychiatric inpatients, differing in level of ego development, explored domains of self-perception that best predicted global self-worth and symptom clusters that best predicted second-order factors of self perception. Findings revealed quantitative and qualitative differences in self-complexities, and more positive self-perceptions among the higher ego-level group in scholastic competence, job competence, and behavioral conduct. Results are discussed from a developmental perspective.

The Department of Defense chemical and biological defense program: where we are going.

This article provides an overview of the Department of Defense (DoD) Chemical and Biological Defense Program (CBDP). This article highlights the mission and objectives of the DoD CBDP, the general capabilities of systems and technologies being developed or employed to defend U.S. forces against the threat of chemical and biological warfare agents, and improvements made in defensive systems in the years since Operation Desert Storm.

Malaria, malnutrition and MSF. Médecins Sans Frontières.

This is a personal account of my brief time in Burundi as a volunteer doctor with Médecins Sans Frontières (MSF) at the beginning of 2001. Burundi is a small nation in central Africa (bounded by the Democratic Republic of Congo, Rwanda and Tanzania) which has suffered from problems between the Hutu and Tutsi "ethnic groups", similar to those for which Rwanda is better known. Unlike Rwanda, the war between government troops and rebel forces continues in Burundi. MSF has been in Burundi since 1992, providing basic healthcare, nutrition programs, surgical services and epidemiological intervention. In late 2000, a malaria epidemic began in Burundi's highland regions where transmission is normally low, and thus the population largely not immune. Malnutrition rates also increased and MSF rapidly expanded its usual program in an attempt to control these new health problems.

Developmental aspects of psychological defenses: their relation to self-complexity, self-perception, and symptomatology in adolescents.

This study investigated developmental aspects of psychological defenses in relation to self-complexity, self-perception, and symptomatology through a comparison of two groups of adolescents characterized by defense maturity level (i.e., immature versus mature defenses). The Defense Style Questionnaire (DSQ-78), the Self-Complexity Inventory (SCI), the Self-Perception Profile for Adolescents, and the Youth Self Report behavior checklist (YSR) were completed by 79 high school students ranging in age from 15 to 18 years. Subjects were characterized as either employing predominantly mature or immature defensive strategies based on median splits of the two defense factors. Dependent variables included the Self-Complexity Inventory, The Youth Self Report and the Self-Perception Profile for Adolescents. The mature defense group (N = 26) reported significantly higher self-complexity than the immature defense group (N = 26), supporting a developmental approach to defense mechanisms. In general, mature defense mechanisms seem to be more adaptive in late adolescence than immature defenses as indicated by higher global self-worth and fewer internalizing and externalizing symptoms. The findings lend support to the developmental approach to the self and highlight the importance of examining psychological indices of development independent of chronological age.

Compulsive-like behavior in individuals with Down syndrome: its relation to mental age level, adaptive and maladaptive behavior.

This study examined the nature of repetitive, ritualistic, and compulsive-like behaviors in 50 typically developing children and 50 individuals with Down syndrome (DS), matched on mental age (MA; M = 59.72 months). Parents reported on their children's compulsive-like behaviors-including ritualistic habits-and perfectionistic behaviors, as well as their children's adaptive and maladaptive behaviors. Results indicated that children with DS show similar MA-related changes in compulsive-like behaviors compared to the MA-matched comparison group. Younger children (both typical and DS) exhibited significantly more compulsive-like behaviors than older children. In general, children with and without DS did not differ from each other in terms of the number of compulsive-like behaviors they engaged in, although participants with DS engaged in more frequent, more intense repetitive behaviors. Compulsive-like behaviors were differentially related to adaptive and maladaptive behaviors across the MA and mental retardation groups. The results extend the "similar sequence" model of development to the construct of compulsive-like behaviors, and also suggest that some repetitive behaviors may be among the behavioral phenotype of individuals with DS.

Trophic accumulation and depuration of mercury by blue crabs (Callinectes sapidus) and pink shrimp (Penaeus duorarum).

Mercury concentrations in blue crabs (Callinectes sapidus) collected from an area of mercury-contaminated sediments in Lavaca Bay, TX, USA, are more than an order of magnitude greater than concentrations in penaeid shrimp from the same area. Laboratory feeding experiments using mercury-contaminated fish as food showed that both blue crabs and pink shrimp (Penaeus duorarum) could accumulate mercury concentrations comparable to those in their food in 28 days. Calculated mercury assimilation efficiencies averaged 76% for blue crabs and 72% for pink shrimp. Significant depuration of mercury by blue crabs was not observed during a subsequent 28-day period, but pink shrimp lost mercury at a rate of about 0.012 day-1. Model calculations predict biomagnification factors of mercury of about two to three at steady state for both species. The large difference in observed concentrations of mercury in field-collected blue crabs and penaeid shrimp does not result from differences in efficiency of mercury assimilation from their food or from differences in excretion rates. It is more likely the result of differences in residence times in the contaminated area and of differences in feeding habits.

Primary open-angle glaucoma patients characterized by ocular vasospasm demonstrate a different ocular vascular response to timolol versus betaxolol.

We evaluated the retrobulbar response to a selective versus nonselective beta blocker in a subgroup of primary open-angle glaucoma patients (POAG) characterized by ocular vasospasm. Eleven patients who exhibited ocular vasospasm (i.e. a significant increase in ophthalmic artery blood flow velocity or a significant decrease in ophthalmic artery resistance index during hypercapnia) underwent medication washout for 4 weeks and were enrolled in a double-masked cross-over study (betaxolol versus timolol). Patients were evaluated for blood flow velocity of the retrobulbar vessels using color Doppler imaging, intraocular pressure, visual field sensitivity and contrast sensitivity at the beginning and end of each 4 week treatment period. Timolol treatment caused a significant reduction in IOP (p = .007), but no change in retrobulbar hemodynamics or visual function. After betaxolol treatment, resistance index fell significantly (p = .040) in the ophthalmic artery and increased significantly in both the central retinal (p = .003) and temporal posterior ciliary arteries (p = .030). Also following betaxolol treatment, contrast sensitivity improved significantly (p = .006), and a significant positive correlation was shown between change in contrast sensitivity and change in resistance index (r = .70; p = .015) of the ciliary arteries. POAG patients characterized by ocular vasospasm display a significant hemodynamic response to betaxolol, but not to timolol.

Early parental preoccupations and behaviors and their possible relationship to the symptoms of obsessive-compulsive disorder.

This study focuses on early parental preoccupations and behaviors (EPPB) surrounding the birth of a new family member. An interview instrument was developed to assess EPPB at eight months prepartum and two weeks and three months postpartum. Measures with adequate psychometric and conceptual properties were used to assess the overall level of parental preoccupations and associated actions as well as three content domains: caregiving (CARE), relationship building (RELATIONSHIP), and anxious intrusive thoughts associated with harm avoidant behaviors (AITHAB). The hypothesis that preoccupations and behaviors would peak for both parents close to the birth of the child was confirmed. Measures of EPPB were distinguished from symptoms of depression and generalized anxiety. Consistent with our a priori hypothesis the content and character of the AITHAB was found to resemble the symptoms of obsessive-compulsive disorder (OCD). The study findings suggest the potential adaptive significance of EPPB and the possible evolutionary origins of OCD.