1,942 research outputs found
The effects on developing countries of the Kyoto Protocol and carbon dioxide emissions trading
The trading of rights to emit carbon dioxide has not officially been sanctioned by the United Nations Framework Convention on Climate Change, but it is of interest to investigate the consequences, both for industrial (Annex B) and developing countries, of allowing such trades. The authors examine the trading of caps assigned to Annex B countries under the Kyoto Protocol and compare the outcome with a world in which Annex B countries meet with their Kyoto targets without trading. Under the trading scenario the former Soviet Union is the main seller of carbon dioxide permits and Japan, the European Union, and the United States are the main buyers. Permit trading is estimated to reduce the aggregate cost of meeting the Kyoto targets by about 50 percent, compared with no trading. Developing countries, though they do not trade, are nonetheless affected by trading. For example, the price of oil and the demand for other developing country exports are higher with trading than without. The authors also consider what might happen if developing countries were to voluntarily accept caps equal to Business as Usual Emissions and were allowed to sell emission reductions below these caps to Annex B countries. The gains from emissions trading could be big enough to give buyers and sellers incentive to support the system. Indeed, a global market for rights to emit carbon dioxide could reduce the cost of meeting the Kyoto targets by almost 90 percent, if the market were to operate competitively. The division of trading gains, however, may make a competitive outcome unlikely: Under perfect competition, the vast majority of trading gains go to buyers of permits rather than to sellers. Even markets in which the supply of permits is restricted can, however, substantially reduce the cost to Annex B countries of meeting their Kyoto targets, while yielding profits to developing countries that elect to sell permits.Economic Theory&Research,Environmental Economics&Policies,Markets and Market Access,Montreal Protocol,Climate Change,Environmental Economics&Policies,Carbon Policy and Trading,Energy and Environment,Economic Theory&Research,Montreal Protocol
X-Ray Absorption Analysis of MCG-6-30-15: Discerning Three Kinematic Systems
By analyzing the X-ray spectrum of MCG-6-30-15 obtained with the HETG
spectrometer on board the Chandra Observatory, we identify three kinematically
distinct absorption systems; two outflow components intrinsic to MCG-6-30-15,
and one local at z = 0. The slow outflow at -100 +/- 50 km s^-1 has a large
range of ionization manifested by absorption from 24 different charge states of
Fe, which enables a detailed reconstruction of the absorption measure
distribution (AMD). This AMD spans five orders of magnitude in ionization
parameter: -1.5 < log xi < 3.5 (cgs units), with a total column density of N_H
= (5.3 +/- 0.7) x 10^21 cm^-2. The fast outflow at -1900 +/- 150 km s^-1 has a
well defined ionization parameter with log xi = 3.82 +/- 0.03 (cgs units) and
column density N_H = 8.1 +/- 0.7 x 10^22 cm^-2. Assuming this component is a
thin, uniform, spherical shell, it can be estimated to lie within 11 light days
of the \agn center. The third component, most clearly detected in the lower
oxygen charge states O^+1 - O^+6, has been confused in the past with the fast
outflow, but is identified here with local gas z = 0 and a total column density
N_H of a few 10^20 cm^-2. Finally, we exploit the excellent spectral resolution
of the HETGS and use the present spectrum to determine the rest-frame
wavelengths of oxygen inner-shell lines that were previously uncertain.Comment: 34 pages, 6 figures, submitted to Ap
Pneumopathie induite par l'hydroxyurée. [Hydroxyurea-induced pneumonia].
International audienceIntroduction: Hydroxyurea is an antimetabolite widely used in the treatment of myeloproliferative diseases. Usual side effects are mainly hematological, gastrointestinal, neurological disorders and induced-fevers. More rarely, hydroxyurea-induced pneumonitis are reported. Case report: We report a case of a patient treated for polycythemia vera. She was admitted 20 days after introduction of hydroxyurea for a high fever, productive cough and clear sputum associated with nausea. Chest CT-scan found diffuse bilateral ground-glass opacities. The microbiological investigations were negative. Symptoms disappeared few days after discontinuation of treatment. Its reintroduction led to recurrence of symptoms. Conclusion: This additional case completes the 15 cases of hydroxyurea-induced pneumonitis described in the literature. Two forms of this disease seem to exist: an acute form with fever occurring in the month following introduction of hydroxyurea; and a chronic form without fever. Even if it is uncommon, pulmonologists should be aware of this complication
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A high-resolution transmission-type x-ray spectrometer designed for observation of the Kα transitions of highly charged high-Z ions
High-resolution reflection-type crystal spectrometers have been used for x-ray energies up to 13 keV, e.g., the K-shell radiation of heliumlike Kr. In order to extend crystal spectrometer measurements to higher energy x rays from higher-Z elements, we employ the crystal in transmission. The geometry we use is known as DuMond geometry. Using such a transmission-type crystal x-ray spectrometer, we have measured the K-shell radiation of various highly charged high-Z ions. In particular, we present a measurement of the 1s2p 1P1→1s2 1S0 transition in heliumlike xenon, Xe52+. For this transition, we measure a linewidth of 34 eV, which demonstrates that the resolving power we achieved with the new spectrometer is on the order of 100
Hyponatremia revisited: Translating physiology to practice
The complexity of hyponatremia as a clinical problem is likely caused by the opposite scenarios that accompany this electrolyte disorder regarding pathophysiology (depletional versus dilutional hyponatremia, high versus low vasopressin levels) and therapy (rapid correction to treat cerebral edema versus slow correction to prevent osmotic demyelination, fluid restriction versus fluid resuscitation). For a balanced differentiation between these opposites, an understanding of the pathophysiology of hyponatremia is required. Therefore, in this review an attempt is made to translate the physiology of water balance regulation to strategies that improve the clinical management of hyponatremia. A physiology-based approach to the patient with hyponatremia is presented, first addressing the possibility of acute hyponatremia, and then asking if and if so why vasopressin is secreted non-osmotically. Additional diagnostic recommendations are not to rely too heavily of the assessment of the extracellular fluid volume, to regard the syndrome of inappropriate antidiuresis as a diagnosis of exclusion, and to rationally investigate the pathophysiology of hyponatremia rather than to rely on isolated laboratory values with arbitrary cutoff values. The features of the major hyponatremic disorders are discussed, including diuretic-induced hyponatremia, adrenal and pituitary insufficiency, the syndrome of inappropriate antidiuresis, cerebral salt wasting, and exercise-associated hyponatremia. The treatment of hyponatremia is reviewed from simple saline solutions to the recently introduced vasopressin receptor antagonists, including their promises and limitations. Given the persistently high rates of hospital-acquired hyponatremia, the importance of improving the management of hyponatremia seems both necessary and achievable. Copyrigh
Incidence of Pneumocystis jiroveci Pneumonia among Groups at Risk in HIV-negative Patients
International audienceBackground - Pneumocystis jiroveci pneumonia in human immunodeficiency virus (HIV)-negative immunocompromised patients is associated with high mortality rates. Although trimethoprim-sulfamethoxazole provides a very effective prophylaxis, pneumocystosis still occurs and may even be emerging due to suboptimal characterization of patients most at risk, hence precluding targeted prophylaxis. Methods - We retrospectively analyzed all cases of documented pneumocystosis in HIV-negative patients admitted in our institution, a referral center in the area, from January 1990 to June 2010, and extracted data on their underlying condition(s). To estimate incidence rates within each condition, we estimated the number of patients followed-up in our area for each condition by measuring the number of patients admitted with the corresponding international classification diagnostic code, through the national hospital discharge database (Program of Medicalization of the Information System [PMSI]). Results - From 1990 to 2010, 293 cases of pneumocystosis were documented, of which 154 (52.6%) tested negative for HIV. The main underlying conditions were hematological malignancies (32.5%), solid tumors (18.2%), inflammatory diseases (14.9%), solid organ transplant (12.3%), and vasculitis (9.7%). Estimated incidence rates could be ranked in 3 categories: 1) high risk (incidence rates >45 cases per 100,000 patient-year): polyarteritis nodosa, granulomatosis with polyangiitis, polymyositis/dermatopolymyositis, acute leukemia, chronic lymphocytic leukemia, and non-Hodgkin lymphoma; 2) intermediate risk (25-45 cases per 100,000 patient-year): Waldenström macroglobulinemia, multiple myeloma, and central nervous system cancer; and 3) low risk (<25 cases per 100,000 patient-year): other solid tumors, inflammatory diseases, and Hodgkin lymphoma. Conclusions - These estimates may be used as a guide to better target pneumocystosis prophylaxis in the groups most at risk
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Laboratory Measurements of Fe XXIV L-Shell Line Emission
Recent ASCA spectra exhibit discrepancies with the relative line intensities of various Fe XXIII and XXIV L-shell emission lines predicted by standard plasma emission codes. To address this issue, we have carried out a series of high-resolution, broadband measurements of Fe XXIV line emission using an electron beam ion trap facility. X-ray lines produced in the trap are detected and resolved using Bragg crystal spectrometers. We report measurements of 3 → 2 and 4 → 2 transitions, which result primarily from electron impact excitation. Overall, good agreement is found with distorted wave calculations
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Measurement and interpretation of the polarization of the x-ray line emission of heliumlike Fe XXV excited by an electron beam
The linear polarization of the 1s2p 1P1→1s2 1S0 resonance line, the 1s2p 3P1,2→1s2 1S0 intercombination lines, and the 1s2s 3S1→1s2 1S0 forbidden line was measured in heliumlike Fe XXV excited near threshold by a monoenergetic electron beam. The measurement was carried out with a high-resolution x-ray spectrometer employing a set of two analyzing crystals that acted as polarizers by selectively reflecting the individual polarization components. A value of +0.56-0.08+0.17 was determined for the polarization of the 1P1 line, -0.53-0.02+0.05 for the 3P2 line, -0.22-0.02+0.05 for the 3P1 line, and -0.076-0.007+0.007 for the 3S1 line. The measurements were compared with results from a relativistic distorted-wave calculation, which was carried out for a number of mid-Z heliumlike ions (Mg10+–Kr34+), and good agreement was found. By contrast, disagreement was noted with predictions based on Coulomb-Born calculations, allowing us to distinguish between theoretical approaches
Nephrogenic syndrome of inappropriate antidiuresis secondary to an activating mutation in the arginine vasopressin receptor AVPR2.
CONTEXT: Nephrogenic syndrome of inappropriate antidiuresis (NSIAD), resulting from activating mutations in the arginine vasopressin receptor type 2 (AVPR2), is a rare cause of hyponatraemia. However, its true prevalence may be underestimated and it should be considered in the investigation of unexplained hyponatraemia, with implications for management and targeted gene testing. OBJECTIVE: We describe a structured approach to the investigation of hyponatraemia in a young patient, which allowed a diagnosis of NSIAD to be made. We review current knowledge of NSIAD and use a structural modelling approach to further our understanding of the potential mechanisms by which the causative mutation leads to a constitutively active AVPR2. DESIGN: Clinical and biochemical investigation of hyponatraemia; a formal water load test with measurement of arginine vasopressin levels (AVP); sequencing of AVPR2; and computed structural modelling of the wild-type and constitutively activated mutant receptors. RESULTS: A 38-year-old man presented with intermittent confusion and nausea associated with hyponatraemia and a biochemical picture consistent with syndrome of inappropriate antidiuretic hormone (SIADH). Adrenocortical and thyroid function and an acute intermittent porphyria screen were normal. Cross-sectional imaging of the head, chest and abdomen did not identify an underlying cause and so we proceeded to a water load test. This demonstrated a marked inability to excrete a free water load (just 15% of a 20 ml/kg oral load by 240 min postingestion), with the onset of hyponatraemia (Na(+) 125 mmol/l, urine osmolality 808 mOsm/kg). However, AVP levels were low throughout the test (0·4-0·9 pmol/l), consistent with a diagnosis of NSIAD. AVPR2 sequencing revealed a previously described hemizygous activating mutation (p.Arg137Cys). Through structural modelling of AVPR2, we suggest that disruption of a hydrogen bond between residues Thr269 and Arg137 may promote stabilization of the receptor in its active conformation. Since diagnosis, the patient has adhered to modest fluid restriction and remained well, with no further episodes of hyponatraemia. CONCLUSION: NSIAD should be considered in young patients with unexplained hyponatraemia. A water load test with AVP measurement is a potentially informative investigation, while AVPR2 sequencing provides a definitive molecular genetic diagnosis and a rationale for long-term fluid restriction.ASP and MG are supported by the National Institute of Health Research Cambridge Biomedical Research Centre.This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1111/cen.1301
Differential Treatment in Environmental Law: Addressing Critiques and Conceptualizing the Next Steps
Differential treatment in international environmental law is the broader manifestation of the principle of common but differentiated responsibilities (CBDRs). It reflects equity concerns that have underlain most environmental debates on a North-South basis for several decades. Over the past couple of decades, different forms of differentiation have been introduced in environmental law instruments to the point where it has become an essential element of any international environmental agreement. At the same time, differential treatment has been the object of sustained criticism, arguing that it should be temporary, that it fails to target beneficiaries appropriately, and undermines environmental outcomes. This article takes the opposite view and argues that differentiation remains crucial in a world where widespread inequalities remain. Beneficiaries need to be identified on the basis of environmental and social indicators and differentiation should constitute the basis on which environmental measures are adopted. Worsening environmental conditions and an evolving global context call for adding new elements to the existing framework for differentiation. This requires thinking beyond the current structure centered around nation states and conceptualizing differentiation around common heritage equity. It also requires expanding differentiation beyond the field of environmental law, to include all areas of sustainable development law. Further, differential treatment needs to be implemented in a way that benefits the most disadvantaged in every country. These measures are necessary to foster a vibrant international environmental law that addresses the equity needs of all states in years to come
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