RESUMO
We present a matrix population model for a single-sex human population comprising non-orphan daughters (whose mothers are alive) and orphan daughters (whose mothers are dead). Orphans suffer higher mortality than non-orphans, which simulates the need for daughters to receive maternal care in order to survive. The way that maternal care affects population dynamics and life-history evolution is then analysed for demographic regimes that encompass large ranges of daughter survival, mother survival and fertility. We provide stable age-distributions of orphans and non-orphans for each regime and perform sensitivity analyses on daughter survival, adult survival and fertility. The results show that natural selection will favour (i) faster daughter independence from maternal care, (ii) higher adult survival at all ages, and (iii) early reproduction to the detriment of late reproduction. We then build scenarios concerning the coevolution of daughter survival and maternal care with adult survival and fertility. We also incorporate grandmaternal care into the model. We show that (i) the acute altriciality of human babies, (ii) the increased maternal care resulting from emergence of complex sociality and (iii) the role played by grandmothers in caring for granddaughters may have led to the emergence of specific human life-history traits: a short reproductive period characterised by a reproductive senescence and menopause, as well as an extended lifespan characterised by a post-reproductive life.
Assuntos
Relação entre Gerações , Modelos Teóricos , Dinâmica Populacional , Feminino , Fertilidade , Humanos , Análise de SobrevidaRESUMO
PURPOSE: Colorectal stents are being used for palliation and as a "bridge to surgery" in obstructing colorectal carcinoma. The purpose of this study was to review our experience with self-expanding metal stents (SEMS) as the initial interventional approach in the management of acute malignant large-bowel obstruction. METHODS: Between February 2002 and August 2009, 93 patients underwent the insertion of a SEMS for an obstructing malignant lesion of the left-sided colon or rectum. RESULTS: In 66 patients, the stents were placed for palliation; whereas, in 27 patients they were placed as a bridge to surgery. Stent placement was technically successful in 92.5% (n = 86) of the patients, with a clinical success rate of 86% (n = 80). Three perforations occurred during stent placement, two were treated by an emergency Hartmann operation, and one by a colostomy. In the intention to treat by stent, the peri-interventional mortality was 6.5% (6/93). Stent migration was reported in three cases (3%), and stent obstruction occurred in 11 cases (12%). Of the 24 patients with stents successfully placed as a bridge to surgery, 22 underwent elective single-stage operations with no death or anastomotic complication. CONCLUSION: Stent insertion provided an effective outcome in patients with malignant colonic obstruction as a palliative and preoperative therapy.
Assuntos
Neoplasias Colorretais/cirurgia , Obstrução Intestinal/cirurgia , Stents/efeitos adversos , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Colorretais/complicações , Feminino , Humanos , Obstrução Intestinal/complicações , Perfuração Intestinal/etiologia , Masculino , Pessoa de Meia-Idade , Cuidados Paliativos , Cuidados Pré-Operatórios , Desenho de Prótese , Estudos RetrospectivosRESUMO
Output-based allocation (OBA) is one of the main options discussed for addressing carbon leakage in emissions trading systems. This paper studies how different OBA designs affect incentives on mitigation and trade in the cement sector. To do so, we develop an analytical model of sector emissions as a function of technical parameters representing abatement levers. We propose a specific design called hybrid OBA, and show that unlike the alternatives, it provides incentives for firms to reduce the carbon intensity of production without offshoring production. We assess the feasibility of hybrid OBA through expert interviews and find that the main barriers identified, including technical and administrative complexities, are manageable. However, hybrid OBA represents a mid-term solution until more robust anti-leakage measures can be introduced, because of two key limitations of OBA in general - it does not provide incentives to reduce the consumption of cement or to accelerate the development of radical low-carbon technologies, both of which are necessary to deliver deep decarbonisation.
RESUMO
BACKGROUND: To validate a new practical Sepsis Severity Score for patients with complicated intra-abdominal infections (cIAIs) including the clinical conditions at the admission (severe sepsis/septic shock), the origin of the cIAIs, the delay in source control, the setting of acquisition and any risk factors such as age and immunosuppression. METHODS: The WISS study (WSES cIAIs Score Study) is a multicenter observational study underwent in 132 medical institutions worldwide during a four-month study period (October 2014-February 2015). Four thousand five hundred thirty-three patients with a mean age of 51.2 years (range 18-99) were enrolled in the WISS study. RESULTS: Univariate analysis has shown that all factors that were previously included in the WSES Sepsis Severity Score were highly statistically significant between those who died and those who survived (p < 0.0001). The multivariate logistic regression model was highly significant (p < 0.0001, R2 = 0.54) and showed that all these factors were independent in predicting mortality of sepsis. Receiver Operator Curve has shown that the WSES Severity Sepsis Score had an excellent prediction for mortality. A score above 5.5 was the best predictor of mortality having a sensitivity of 89.2 %, a specificity of 83.5 % and a positive likelihood ratio of 5.4. CONCLUSIONS: WSES Sepsis Severity Score for patients with complicated Intra-abdominal infections can be used on global level. It has shown high sensitivity, specificity, and likelihood ratio that may help us in making clinical decisions.