Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 108
Filter
1.
Earths Future ; 10(11): e2022EF002751, 2022 Nov.
Article in English | MEDLINE | ID: mdl-36590252

ABSTRACT

Sea level rise (SLR) is a long-lasting consequence of climate change because global anthropogenic warming takes centuries to millennia to equilibrate for the deep ocean and ice sheets. SLR projections based on climate models support policy analysis, risk assessment and adaptation planning today, despite their large uncertainties. The central range of the SLR distribution is estimated by process-based models. However, risk-averse practitioners often require information about plausible future conditions that lie in the tails of the SLR distribution, which are poorly defined by existing models. Here, a community effort combining scientists and practitioners builds on a framework of discussing physical evidence to quantify high-end global SLR for practitioners. The approach is complementary to the IPCC AR6 report and provides further physically plausible high-end scenarios. High-end estimates for the different SLR components are developed for two climate scenarios at two timescales. For global warming of +2°C in 2100 (RCP2.6/SSP1-2.6) relative to pre-industrial values our high-end global SLR estimates are up to 0.9 m in 2100 and 2.5 m in 2300. Similarly, for a (RCP8.5/SSP5-8.5), we estimate up to 1.6 m in 2100 and up to 10.4 m in 2300. The large and growing differences between the scenarios beyond 2100 emphasize the long-term benefits of mitigation. However, even a modest 2°C warming may cause multi-meter SLR on centennial time scales with profound consequences for coastal areas. Earlier high-end assessments focused on instability mechanisms in Antarctica, while here we emphasize the importance of the timing of ice shelf collapse around Antarctica. This is highly uncertain due to low understanding of the driving processes. Hence both process understanding and emission scenario control high-end SLR.

2.
Psychol Med ; 47(8): 1389-1401, 2017 Jun.
Article in English | MEDLINE | ID: mdl-28100283

ABSTRACT

BACKGROUND: Cortisol is the primary output of the hypothalamic-pituitary-adrenal (HPA) axis and is central to the biological stress response, with wide-ranging effects on psychiatric health. Despite well-studied biological pathways of glucocorticoid function, little attention has been paid to the role of genetic variation. Conventional salivary, urinary and serum measures are strongly influenced by diurnal variation and transient reactivity. Recently developed technology can be used to measure cortisol accumulation over several months in hair, thus indexing chronic HPA function. METHOD: In a socio-economically diverse sample of 1070 twins/multiples (ages 7.80-19.47 years) from the Texas Twin Project, we estimated effects of sex, age and socio-economic status (SES) on hair concentrations of cortisol and its inactive metabolite, cortisone, along with their interactions with genetic and environmental factors. This is the first genetic study of hair neuroendocrine concentrations and the largest twin study of neuroendocrine concentrations in any tissue type. RESULTS: Glucocorticoid concentrations increased with age for females, but not males. Genetic factors accounted for approximately half of the variation in cortisol and cortisone. Shared environmental effects dissipated over adolescence. Higher SES was related to shallower increases in cortisol with age. SES was unrelated to cortisone, and did not significantly moderate genetic effects on either cortisol or cortisone. CONCLUSIONS: Genetic factors account for sizable proportions of glucocorticoid variation across the entire age range examined, whereas shared environmental influences are modest, and only apparent at earlier ages. Chronic glucocorticoid output appears to be more consistently related to biological sex, age and genotype than to experiential factors that cluster within nuclear families.

3.
Phys Rev Lett ; 114(14): 145004, 2015 Apr 10.
Article in English | MEDLINE | ID: mdl-25910132

ABSTRACT

Experiments have recently been conducted at the National Ignition Facility utilizing inertial confinement fusion capsule ablators that are 175 and 165 µm in thickness, 10% and 15% thinner, respectively, than the nominal thickness capsule used throughout the high foot and most of the National Ignition Campaign. These three-shock, high-adiabat, high-foot implosions have demonstrated good performance, with higher velocity and better symmetry control at lower laser powers and energies than their nominal thickness ablator counterparts. Little to no hydrodynamic mix into the DT hot spot has been observed despite the higher velocities and reduced depth for possible instability feedthrough. Early results have shown good repeatability, with up to 1/2 the neutron yield coming from α-particle self-heating.

5.
J Perinatol ; 33(8): 657-8, 2013 Aug.
Article in English | MEDLINE | ID: mdl-23897312

ABSTRACT

Severe combined immunodeficiency (SCID) is a potentially fatal disorder characterized by defective T- and B-lymphocyte function. We describe a 34-week female twin who had developed feeding intolerance, perioral cyanosis, abdominal distension and neutropenia at 1 month of age. Despite several evaluations including an 'inconclusive' newborn screening result for SCID, the presence of profound lymphopenia was unappreciated. Eventually a diagnosis of SCID in association with adenosine deaminase deficiency was made. This case serves to emphasize the importance of newborn screening for SCID in the context of careful evaluation of clinical and laboratory findings that may be overlooked and result in a delay in the diagnosis of a potentially life-threatening condition.


Subject(s)
Neonatal Screening , Severe Combined Immunodeficiency/diagnosis , Adenosine Deaminase/deficiency , Diseases in Twins/diagnosis , Female , Humans , Infant, Newborn
6.
Rev Sci Instrum ; 83(10): 10D905, 2012 Oct.
Article in English | MEDLINE | ID: mdl-23126909

ABSTRACT

The gamma reaction history diagnostic at the National Ignition Facility has the capability to determine a number of important performance metrics for cryogenic deuterium-tritium implosions: the fusion burn width, bang time and yield, as well as the areal density of the compressed ablator. Extracting those values from the measured γ rays of an implosion, requires accounting for a γ-ray background in addition to the impulse response function of the instrument. To address these complications, we have constructed a model of the γ-ray signal, and are developing a simultaneous multi-shot fitting routine to constrain its parameter space.

7.
J Neuroimmune Pharmacol ; 7(4): 981-90, 2012 Dec.
Article in English | MEDLINE | ID: mdl-23065459

ABSTRACT

The effects of HIV on brain metabolites and cognitive function are not well understood. Sixteen HIV+youths (15 vertical, 1 transfusion transmissions) receiving combination antiretroviral therapy and 14 age-matched HIV- youths (13-25 years of age) were evaluated with brain two-dimensional (2D) magnetic resonance spectroscopy (MRS) at 3 Tesla (T) and a neuropsychological battery that assessed three cognitive domains (attention/processing speed, psychomotor ability, and executive function). The relationship between brain metabolite ratios and cognitive performance was explored. Compared to HIV- controls, HIV+ subjects had higher sycllo-inositol (Scy)/total creatine (tCr) (+32%, p = 0.016) and higher Scy/total choline (tCho) (+31%, p = 0.018) on 2D-MRS in the right frontal lobe. HIV+ subjects also had higher glutamate (Glu)/tCr (+13%, p = 0.022) and higher Glu/tCho (+15%, p = 0.048) than controls. HIV+ subjects demonstrated poorer attention/processing speed (p = 0.011, d = 1.03) but similar psychomotor and executive function compared to HIV- controls. The attention/processing score also correlated negatively with the ratio of N-acetylaspartate (NAA) to tCr on 2D-MRS (r = -0.75, p = 0.0019) in the HIV- controls, but not in the HIV+ subjects (Fisher's r-z transformation, p < 0.05). Our results suggest that attention/processing speed is impacted by early HIV infection and is associated with right hemisphere NAA/tCr. Scy and Glu ratios are also potential markers of brain health in chronic, lifelong HIV infection in perinatally infected youths receiving antiretroviral therapy.


Subject(s)
Brain Chemistry/physiology , HIV Infections/metabolism , HIV Infections/psychology , Adolescent , Amino Acids/blood , Aspartic Acid/analogs & derivatives , Aspartic Acid/blood , CD4 Lymphocyte Count , Child , Cognition/physiology , Female , Frontal Lobe/pathology , HIV Seropositivity/metabolism , HIV Seropositivity/psychology , Humans , Magnetic Resonance Imaging , Male , Neuropsychological Tests , Problem Solving , Psychomotor Performance/physiology , Young Adult
8.
Br J Dermatol ; 162(1): 159-61, 2010 Jan.
Article in English | MEDLINE | ID: mdl-19849698

ABSTRACT

Background A significant proportion of young children with atopic dermatitis (AD) is sensitized to microbial allergens, which play a potential role in the pathogenesis of AD inflammation. Objective To study the timing of IgE sensitization to microbial allergens including staphylococcal superantigens, Malassezia species and Candida albicans in young children with AD. Method Specific IgE antibodies to staphylococcal superantigens, Malassezia species, C. albicans and control inhalant/food allergens were measured in 53 young children with mild to moderate AD. The presence of IgE sensitization relative to age (> or = 3 years vs. < 3 years) was analysed by logistic regressions. Results IgE sensitization to the staphylococcal superantigen group, Malassezia species and C. albicans was significantly associated with older age in children with AD [P = 0.02, odds ratio (OR) 4.9; P = 0.02, OR 4.7; and P = 0.05, OR 4.0, respectively]. Conclusion IgE sensitization to microbial allergens is associated with an older age group in young children with mild to moderate AD.


Subject(s)
Candida albicans/immunology , Dermatitis, Atopic/immunology , Immunoglobulin E/immunology , Malassezia/immunology , Staphylococcus/immunology , Superantigens/immunology , Age Factors , Child , Child, Preschool , Dermatitis, Atopic/etiology , Female , Food Hypersensitivity/diagnosis , Food Hypersensitivity/immunology , Humans , Immunoglobulin E/blood , Infant , Logistic Models , Male , Superantigens/blood
9.
Phys Rev Lett ; 93(4): 042501, 2004 Jul 23.
Article in English | MEDLINE | ID: mdl-15323753

ABSTRACT

The 9Be(32Ar, 31Ar)X reaction, leading to the 5/2+ ground state of a nucleus at the proton drip line, has a cross section of 10.4(13) mb at a beam energy of 65.1 MeV/nucleon. This translates into a spectroscopic factor that is only 24(3)% of that predicted by the many-body shell-model theory. We introduce refinements to the eikonal reaction theory used to extract the spectroscopic factor to clarify that this very strong reduction represents an effect of nuclear structure. We suggest that it reflects correlation effects linked to the high neutron separation energy (22.0 MeV) for this state.

10.
Phys Rev Lett ; 91(1): 012501, 2003 Jul 04.
Article in English | MEDLINE | ID: mdl-12906536

ABSTRACT

The reaction 9Be(28Mg,26Ne+gamma)X has been studied at 82 MeV/nucleon together with two similar cases, 30Mg and 34Si. Strong evidence that the reactions are direct is offered by the parallel-momentum distributions of the reaction residues and by the inclusive cross sections. The pattern of the partial cross sections for 28Mg suggests the presence of correlations. A preliminary theoretical discussion based on eikonal reaction theory and the many-body shell model is presented. The reaction holds great promise for the study of neutron-rich nuclei.

11.
Phys Rev Lett ; 88(17): 172502, 2002 Apr 29.
Article in English | MEDLINE | ID: mdl-12005747

ABSTRACT

We measured the strength of the 0(+)(gs)-->2(+)(1) excitations in the radioactive mirror nuclei 32Ar and 32Si using the techniques of intermediate-energy Coulomb excitation for 32Ar and inelastic proton scattering in inverse kinematics for 32Si. The 32Ar measurement, taken together with previously existing Coulomb excitation data for 32Si, yields the isoscalar and isovector multipole matrix elements for the 0(+)(1)-->2(+)(1) transition between T = 2 states in the A = 32 system. The proton scattering measurement for 32Si, when combined with the Coulomb excitation data for this nucleus, yields a ratio of neutron and proton matrix elements, M(n)/M(p), for 32Si.

12.
J Pediatr Surg ; 36(12): 1777-80, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11733905

ABSTRACT

PURPOSE: The aim of this study was to characterize the perioperative complications of central venous catheter placement in children infected with human immunodeficiency virus (HIV) METHODS: A retrospective chart review was conducted of all central venous catheters placed by the surgical service into HIV-infected children from 1988 to 1998 at a large urban children's hospital. Complications occurring within 1 month of catheter placement were analyzed for several host and environmental factors. RESULTS: Forty HIV-positive patients underwent 60 central venous access procedures. Thirty-two of the patients were severely immunosuppressed. Eight catheter placements (13%) resulted in perioperative complications, including hemorrhage (n = 2), site infection (n = 2), catheter sepsis (n = 2), thrombotic occlusion (n = 1), and a pleural effusion secondary to catheter malposition (n = 1). Only 3 patients required catheter removal. There was no significant relationship between either hemophilia or thrombocytopenia and perioperative hemorrhage. No significant relationship was found between infectious complications and preoperative white blood cell count, absolute neutrophil count, CD4% and CD4#, suggesting that a patient's compromised immune status should not be considered a contraindication to central venous catheter placement. CONCLUSION: The complication rate of central venous catheter placement into HIV-infected children is low (<15%), but is still higher than that of the general pediatric population. With careful preoperative preparation this procedure can be performed safely, even in patients with advanced HIV disease. J Pediatr Surg 36:1777-1780.


Subject(s)
Catheterization, Central Venous/adverse effects , HIV Infections/therapy , Postoperative Complications/etiology , Adolescent , Adult , Child , Child, Preschool , HIV Infections/immunology , Humans , Infant , Intraoperative Complications/etiology , Intraoperative Complications/prevention & control , Perioperative Care , Postoperative Complications/prevention & control , Postoperative Hemorrhage/etiology , Postoperative Hemorrhage/prevention & control , Preoperative Care , Retrospective Studies
13.
Science ; 294(5543): 802-3, 2001 Oct 26.
Article in English | MEDLINE | ID: mdl-11679657

ABSTRACT

Sea levels are rising as a result of global warming, but assessing the rate of the rise is proving difficult. In his Perspective, Church highlights the report by Cabanes et al., who have reassessed observational data and find that it is closer to model estimates than previously found. However, observational data are still limited and models disagree in their regional projections. With present data and models, regional sea-level changes cannot be predicted with confidence.

14.
J Pediatr ; 138(5): 748-51, 2001 May.
Article in English | MEDLINE | ID: mdl-11343055

ABSTRACT

A child with controlled human immunodeficiency virus infection presented with neurologic deterioration, lactic acidosis, and organic aciduria. Muscle biopsy revealed abnormal mitochondrial (mt) morphology, reduced mt enzyme activities, and mtDNA depletion. After adjustment of antiretroviral therapy to a regimen free of nucleoside analogs, marked improvement was seen in clinical status and mt abnormalities.


Subject(s)
Acidosis/etiology , Antiretroviral Therapy, Highly Active/adverse effects , DNA, Mitochondrial/metabolism , Liver Failure/chemically induced , Muscle, Skeletal/pathology , Antiretroviral Therapy, Highly Active/methods , Biopsy , Child, Preschool , DNA, Mitochondrial/genetics , HIV Infections/drug therapy , Humans , Male , Spectrophotometry
15.
Antimicrob Agents Chemother ; 45(3): 758-63, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11181356

ABSTRACT

The results of the development of dosing guidelines for stavudine in human immunodeficiency virus (HIV)-infected children are summarized. Included in the integrated analyses were 21 and 33 HIV-infected pediatric and adult patients, respectively, from three phase I-II studies. Data for 21 children and 18 adults who received intravenous doses of 0.125 to 2 and 0.5 to 1 mg/kg of body weight, respectively, were used for the determination of dosing guidelines; exposure data for 16 children and 15 adults who received oral doses of 1 to 2 and 0.5 to 1 mg/kg/day, respectively, were used to validate the dosing recommendations for children. Significant relationships were observed between total body clearance (in milliliters per minute) in children and adults combined and demographic parameters of age, body weight, and body surface area (R(2) = 0.77 to 0.80; P = 0.0001). Models of approximated pediatric dose based on clearance values and direct adult exposure yielded a stavudine dosage of 2 mg/kg/day for children of < or =30 kg of body weight and 1 mg/kg/day (adult dose) for children of >30 kg of body weight.


Subject(s)
Anti-HIV Agents/administration & dosage , HIV Infections/drug therapy , Stavudine/administration & dosage , Administration, Oral , Adult , Anti-HIV Agents/pharmacokinetics , Anti-HIV Agents/therapeutic use , Child , Child, Preschool , Dose-Response Relationship, Drug , Female , HIV Infections/metabolism , Humans , Infant , Male , Middle Aged , Stavudine/pharmacokinetics , Stavudine/therapeutic use
16.
Pediatrics ; 107(1): E4, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11134468

ABSTRACT

OBJECTIVES: Abacavir (ABC) is a potent inhibitor of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase. We compared the efficacy, safety, and tolerability of combination therapy with ABC, lamivudine (3TC), and zidovudine (ZDV) versus 3TC and ZDV in antiretroviral experienced HIV-1-infected children over 48 weeks. METHODS: Two hundred five HIV-1-infected children who had received previous antiretroviral therapy and had CD4(+) cell counts >/=100 cells/mm(3) were stratified by age and by previous treatment. Participants were randomly assigned to receive ABC (8 mg/kg twice daily [BID]) plus 3TC (4 mg/kg BID) and ZDV (180 mg/m(2) BID; ABC/3TC/ZDV group) or ABC placebo plus 3TC (4 mg/kg BID) and ZDV (180 mg/m(2); 3TC/ZDV group). Participants who met a protocol-defined switch criteria (plasma HIV-1 RNA >0.5 log(10) copies/mL above baseline at week 8 or >10 000 copies/mL after week 16) had the option to switch to open-label ABC plus any antiretroviral combination or continue randomized therapy or withdraw from the study. RESULTS: The Kaplan-Meier estimates (95% confidence interval) of the proportion of participants who maintained HIV-1 RNA levels 10 000 copies/mL, a significantly higher proportion of participants in the ABC/3TC/ZDV group had HIV-1 RNA

Subject(s)
Acquired Immunodeficiency Syndrome/drug therapy , Anti-HIV Agents/therapeutic use , Dideoxynucleosides/administration & dosage , Lamivudine/administration & dosage , Zidovudine/administration & dosage , Adolescent , Anti-HIV Agents/adverse effects , CD4 Lymphocyte Count , Child , Child, Preschool , Confidence Intervals , Disease Progression , Double-Blind Method , Drug Administration Schedule , Drug Therapy, Combination , Female , Growth/drug effects , HIV-1/genetics , Humans , Infant , Male , RNA, Viral/analysis , RNA, Viral/drug effects
18.
Postgrad Med ; 107(4): 163-6, 169-71, 175-6 passim, 2000 Apr.
Article in English | MEDLINE | ID: mdl-10778419

ABSTRACT

HIV infects and affects children differently than it does adults. An understanding of the epidemiology of pediatric HIV infection may reveal opportunities to reduce and perhaps eliminate perinatal transmission. Knowledge of unique diagnostic features of HIV-exposed newborns and pathogenetic characteristics reflected in clinical manifestations helps physicians meet the management challenges presented by children with HIV and their families.


Subject(s)
HIV Infections , Child , HIV Infections/diagnosis , HIV Infections/therapy , Humans , Infant , Infant, Newborn
19.
J Am Diet Assoc ; 100(3): 323-9, 2000 Mar.
Article in English | MEDLINE | ID: mdl-10719406

ABSTRACT

OBJECTIVE: To produce a simple and effective instrument to evaluate and monitor the nutritional risk of children infected with the human immunodeficiency virus (HIV). DESIGN: The test instrument was developed in consultation with 5 physicians, 5 nutritionists, and 5 social workers with expertise in caring for HIV-infected children. Patient information was collected through medical record review for 19 sociodemographic, 10 anthropometric, 4 biochemical, 6 dietary intake, and 19 medical factors. As a part of routine nutrition care, anthropometric data were obtained and the caregiver was asked to complete a 3-day diet record. Also recorded were the most recent CD4+ T-cell numbers and serum HIV p24 antigen and plasma HIV RNA levels. SUBJECTS/SETTING: Thirty-nine HIV-infected children were selected using quota sampling; that is, subjects were stratified by clinical class as defined by the Centers for Disease Control and Prevention. STATISTICAL ANALYSIS: The severity or degree of potential nutritional risk in each section (anthropometric, biochemical, dietary intake, and medical data) was graded (0 to 4, 0 = low risk) and summed. Reliability of internal consistency was determined through covariance matrixes. Validity was determined through Pearson product moment correlation coefficients to measure convergent and divergent validity; predictive validity was determined using analysis of variance. Correlation for validity was compared to 6 selected dependent variables: weight for height, weight growth velocity, lean body mass, serum albumin level, CD4+ T-cell numbers, and quantitative plasma HIV RNA levels. RESULTS: Of the 38 factors that were analyzed for reliability, 11 fell in the strongly reliable range: height for age, weight for age, clinical class, somatic protein stores, mid-arm circumference, weight for height, serum albumin, immunologic status, body mass index, energy intake, and opportunistic infection. CONCLUSIONS: Anthropometric, dietary intake, and medical data were reliable indicators of nutritional risk. The entire instrument was reliable after 8 of the weakest items were removed. The instrument was found to be valid and a good predictor of nutritional risk in HIV-infected children.


Subject(s)
Diet , HIV Infections/physiopathology , Nutrition Disorders/etiology , Adolescent , Anthropometry , Child , Child, Preschool , Cross-Sectional Studies , Diet Records , Dietary Proteins/administration & dosage , Energy Intake , Female , HIV Infections/complications , Humans , Infant , Iron/blood , Male , Medical Records , Nutrition Disorders/epidemiology , Nutrition Policy , Prealbumin/analysis , Reproducibility of Results , Risk Factors , Serum Albumin/analysis , Zinc/blood
SELECTION OF CITATIONS
SEARCH DETAIL
...