The evolution of the Earth's climate over the twenty-first century depends on the rate at which anthropogenic carbon dioxide emissions are removed from the atmosphere by the ocean and land carbon ...cycles. Coupled climate-carbon cycle models suggest that global warming will act to limit the land-carbon sink, but these first generation models neglected the impacts of changing atmospheric chemistry. Emissions associated with fossil fuel and biomass burning have acted to approximately double the global mean tropospheric ozone concentration, and further increases are expected over the twenty-first century. Tropospheric ozone is known to damage plants, reducing plant primary productivity and crop yields, yet increasing atmospheric carbon dioxide concentrations are thought to stimulate plant primary productivity. Increased carbon dioxide and ozone levels can both lead to stomatal closure, which reduces the uptake of either gas, and in turn limits the damaging effect of ozone and the carbon dioxide fertilization of photosynthesis. Here we estimate the impact of projected changes in ozone levels on the land-carbon sink, using a global land carbon cycle model modified to include the effect of ozone deposition on photosynthesis and to account for interactions between ozone and carbon dioxide through stomatal closure. For a range of sensitivity parameters based on manipulative field experiments, we find a significant suppression of the global land-carbon sink as increases in ozone concentrations affect plant productivity. In consequence, more carbon dioxide accumulates in the atmosphere. We suggest that the resulting indirect radiative forcing by ozone effects on plants could contribute more to global warming than the direct radiative forcing due to tropospheric ozone increases.
In this study, we present the results of nitrogen deposition on land from a set of 29 simulations from six different tropospheric chemistry models pertaining to present‐day and 2100 conditions. ...Nitrogen deposition refers here to the deposition (wet and dry) of all nitrogen‐containing gas phase chemical species resulting from NOx (NO + NO2) emissions. We show that under the assumed IPCC SRES A2 scenario the global annual average nitrogen deposition over land is expected to increase by a factor of ∼2.5, mostly because of the increase in nitrogen emissions. This will significantly expand the areas with annual average deposition exceeding 1 gN/m2/year. Using the results from all models, we have documented the strong linear relationship between models on the fraction of the nitrogen emissions that is deposited, regardless of the emissions (present day or 2100). On average, approximately 70% of the emitted nitrogen is deposited over the landmasses. For present‐day conditions the results from this study suggest that the deposition over land ranges between 25 and 40 Tg(N)/year. By 2100, under the A2 scenario, the deposition over the continents is expected to range between 60 and 100 Tg(N)/year. Over forests the deposition is expected to increase from 10 Tg(N)/year to 20 Tg(N)/year. In 2100 the nitrogen deposition changes from changes in the climate account for much less than the changes from increased nitrogen emissions.
We investigate whether firms with strong corporate governance benefit from higher credit ratings relative to firms with weaker governance. We document, after controlling for firm-specific risk ...characteristics, that credit ratings are negatively associated with the number of blockholders and CEO power, and positively related to takeover defenses, accrual quality, earnings timeliness, board independence, board stock ownership, and board expertise. We also provide evidence that CEOs of firms with speculative-grade credit ratings are overcompensated to a greater degree than their counterparts at firms with investment-grade ratings, thus providing one explanation for why some firms operate with weak governance.
According to a recent evolutionary life history model of development proposed by Ellis, Figueredo, Brumbach, and Schlomer (2009), growing up in harsh versus unpredictable environments should have ...unique effects on life history strategies in adulthood. Using data from the Minnesota Longitudinal Study of Risk and Adaptation, we tested how harshness and unpredictability experienced in early childhood (age 0-5) versus in later childhood (age 6-16) uniquely predicted sexual and risky behavior at age 23. Findings showed that the strongest predictor of both sexual and risky behavior was an unpredictable environment between ages 0 and 5. Individuals exposed to more unpredictable, rapidly changing environments during the first 5 years of life displayed a faster life history strategy at age 23 by having more sexual partners, engaging in more aggressive and delinquent behaviors, and being more likely to be associated with criminal activities. In contrast, exposure to either harsh environments or experiencing unpredictability in later childhood (age 6-16) was, for the most part, not significantly related to these outcomes at age 23. Viewed together, these findings show that unpredictable rather than merely harsh childhood environments exert unique effects on risky behavior later in life consistent with a faster life history strategy. The findings also suggest that there is a developmentally sensitive period for assessing environmental unpredictability during the first 5 years of life. (Contains 8 tables and 5 footnotes.)
This study examines whether acquirers make better acquisition decisions when target firms’ financial statements exhibit greater comparability with industry peer firms. We predict and find that ...acquirers make more profitable acquisition decisions when target firms’ financial statements are more comparable—as evidenced by higher merger announcement returns, higher acquisition synergies, and better future operating performance. We also find that post‐acquisition goodwill impairments and post‐acquisition divestitures are less likely when target firms’ financial statements are more comparable. Finally, we find that acquirers benefit most from comparability when acquirers’ ex ante information asymmetry is higher, acquirers operate in volatile operating environments, and management knows relatively less about the target. In total, our evidence suggests targets’ financial statement comparability helps acquirers make better acquisition‐investment decisions and fosters more efficient capital allocation.
Comparabilité des états financiers et efficience des décisions d'acquisition
Les auteurs se demandent si les acquéreurs prennent de meilleures décisions d'acquisition lorsque la comparabilité des états financiers des sociétés cibles avec ceux des sociétés homologues du même secteur d'activité est plus grande. Ils formulent et démontrent l'hypothèse selon laquelle les acquéreurs prennent des décisions d'acquisition plus rentables lorsque les états financiers des sociétés cibles sont davantage comparables — ce dont témoignent des rendements supérieurs associés à l'annonce d'une fusion, des effets de synergie plus importants résultant de l'acquisition et un meilleur rendement de l'exploitation futur. Les auteurs constatent également que les dépréciations de l’écart d'acquisition et les dessaisissements postérieurs à l'acquisition sont moins probables lorsque la comparabilité des états financiers des sociétés cibles est plus grande. Enfin, ils observent que les acquéreurs bénéficient davantage de la comparabilité dans les cas où l'asymétrie de l'information ex ante des acquéreurs est plus importante, où les acquéreurs exercent leurs activités dans des environnements d'exploitation volatils et où la direction connaît moins bien la société cible. Dans l'ensemble, les données recueillies par les auteurs donnent à penser que la comparabilité des états financiers des sociétés cibles aide les acquéreurs à prendre de meilleures décisions d'acquisition et d'investissement et accroît l'efficience de l'affectation du capital.
Environmental justice research on flooding has relied heavily on analyses of aggregated geographic areal units and assessing exposure to ‘pre-flood’ risks (e.g., residence in 100-year flood zones) ...rather than actual flood events. To address these limitations, we examined disproportionate exposure to flooding caused by Hurricane Harvey in 2017 in Greater Houston (Texas). Using primary survey data collected from 377 representative households before Harvey and spatial data on Harvey-induced inundation developed by the US Federal Emergency Management Agency, we found that the areal extent of flooding around residents' home sites was distributed inequitably with respect to race/ethnicity and socioeconomic status (SES). Hispanic, black and other racial/ethnic minority households experienced more extensive flooding than white households, and lower SES households faced more extensive flooding than higher SES households. Findings align with prior flood risk research in Greater Houston and provide cause for concern, as social inequities in flood exposure may have influenced social disparities in flood impacts and post-disaster needs. Since flood events in Greater Houston are expected to increase in frequency and magnitude due to climate change, socially disparate impacts are likely to become an increasingly salient public policy issue. Thus, proactive approaches for reducing flood risks and ameliorating disparities should be implemented.
•Hurricane Harvey generated major flood impacts in Greater Houston, Texas.•There were household-level social disparities in exposures to Harvey flooding.•Racial/ethnic minority households had more extensive flooding at their home sites.•Lower socioeconomic status households more extensive flooding at their home sites.•Socially unequal flood exposures may have influenced disparate disaster impacts.
Personalized prophylaxis COLLINS, P. W.
Haemophilia : the official journal of the World Federation of Hemophilia,
July 2012, Letnik:
18, Številka:
s4
Journal Article
Recenzirano
Odprti dostop
Prophylaxis is the recommended treatment for people with severe haemophilia. It is unlikely that a single prophylactic regimen, for example based on weight, would be optimal for all patients and ...therefore each individual should have a personalized regimen, agreed between themselves and their haemophilia centre. This regimen should take into account the individual’s bleeding pattern, the condition of their musculoskeletal system, level and timing of physical activity and measurement of coagulation factor in their blood. It is important to recognize that prophylactic regimens are likely to need to change with time as the circumstances of an individual change. For example, activity may change with age or with the season and an individual’s factor VIII pharmacokinetics vary with age. Knowledge of a patient’s pharmacokinetics is likely to help personalize prophylaxis when combined with other information. Factor VIII pharmacokinetics are simple to measure in routine clinical practice and can be adequately calculated from 2 to 3 blood samples combined with a simple to use computer program. Prophylaxis is expensive and, in countries with a limited health care budget, ways to improve its cost effectiveness need to be considered to allow increased access to this treatment. For example, increasing the frequency of prophylaxis can dramatically reduce the amount of treatment required to sustain measureable factor levels and hence reduce cost. The introduction of longer‐acting coagulation factors may necessitate a change in concepts about prophylaxis because whilst these agents may sustain an apparently adequate trough level with fewer infusions, the length of time a person spends at a low level will be increased and this could increase the risk of bleeding, especially at the time of increased physical activity. There is convincing evidence that prophylaxis is the optimal therapy for severe haemophilia, optimizing treatment for each individual and increasing access to this treatment modality are important goals for the future.
Postpartum haemorrhage (PPH) is a major risk factor for maternal morbidity and mortality. PPH has numerous causative factors, which makes its occurrence and severity difficult to predict. Underlying ...haemostatic imbalances such as consumptive and dilutional coagulopathies may develop during PPH, and can exacerbate bleeding and lead to progression to severe PPH. Monitoring coagulation status in patients with PPH may be crucial for effective haemostatic management, goal-directed therapy, and improved outcomes. However, current PPH management guidelines do not account for the altered baseline coagulation status observed in pregnant patients, and the appropriate transfusion triggers to use in PPH are unknown, due to a lack of high-quality studies specific to this area. In this review, we consider the evidence for the use of standard laboratory-based coagulation tests and point-of-care viscoelastic coagulation monitoring in PPH. Many laboratory-based tests are unsuitable for emergency use due to their long turnaround times, so have limited value for the management of PPH. Emerging evidence suggests that viscoelastic monitoring, using thrombelastography- or thromboelastometry-based tests, may be useful for rapid assessment and for guiding haemostatic therapy during PPH. However, further studies are needed to define the ranges of reference values that should be considered ‘normal’ in this setting. Improving awareness of the correct application and interpretation of viscoelastic coagulation monitoring techniques may be critical in realizing their emergency diagnostic potential.
Social determinants of health have received increasing attention in public health, leading to increased understanding of how social factors-individual and contextual-shape the health of the mother ...and infant. However, racial differences in birth outcomes persist, with incomplete explanation for the widening disparity. Here, we highlight the social determinants of preterm birth, with special attention to the social experiences among African American women, which are likely attributed to structural racism and discrimination throughout life.
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