An analysis of the learning activities in seven fifth-grade American history textbooks

Thesis (Ed.M.)--Boston University, 1949. This item was digitized by the Internet Archive

Generation Of Entanglement In Quantum Parametric Oscillators Using Phase Control.

The control of quantum entanglement in systems in contact with environment plays an important role in information processing, cryptography and quantum computing. However, interactions with the environment, even when very weak, entail decoherence in the system with consequent loss of entanglement. Here we consider a system of two coupled oscillators in contact with a common heat bath and with a time dependent oscillation frequency. The possibility to control the entanglement of the oscillators by means of an external sinusoidal perturbation applied to the oscillation frequency has been theoretically explored. We demonstrate that the oscillators become entangled exactly in the region where the classical counterpart is unstable, otherwise when the classical system is stable, entanglement is not possible. Therefore, we can control the entanglement swapping from stable to unstable regions by adjusting amplitude and phase of our external controller. We also show that the entanglement rate is approximately proportional to the real part of the Floquet coefficient of the classical counterpart of the oscillators. Our results have the intriguing peculiarity of manipulating quantum information operating on a classical system.51315

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18–49, 50–69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population

Implications of landuse /cover changes over three decades on community livelihoods within the context of REDD : a case study of Mgori forest in Singida

Abstract The majority of communities living in rural areas of Tanzania depends on natural resources in particular forests and woodlands for their livelihoods. As a result forests and woodlands have been under pressure with declining tendencies in terms of their cover in many parts of Tanzania. Apart from their potential in supporting community livelihoods, forests also contributes to climate change mitigations by reducing carbon emissions. Few remaining forests if well managed can effectively support communities in a number of ways including carbon trade if REDD initiative is well implemented. It therefore very crucial to investigate the dynamics of landuse changes over time and possible implications to community livelihoods to forest depended communities within the context of REDD. The present study investigated landuse change over time at Mgori where PFM involving a total of 5 villages is involved. The study also established that woodlands decreased by 53.8% within a period of 10 years from 1990 to 2010 on the expense bushland which increased by 22.9%. In general agricultural land also increased by 4.8% and this was linked to expansion of crop land due to much dependence on community livelihoods by between 65 and 70%. In general the area is potential for REDD project because of the presence of woodlands, experience of communities on forest governance under CBFM as well as realizing various opportunities REDD may present which are more than challenges. However much more effort is needed to ensure that communities are well educated on potential benefits associated with REDD.CCIA

Implications of present and future landcover change on small holder agriculture within the context of REDD+ in Tanzania: a case of Mgori forests in Singida rural District

Mgori forest is located in Singida Rural district and is under Community Based Forest Management (CBFM). The forest has maintained its forest status and in general has demonstrated its potential for Reduced Emission from Deforestation and forest Degradation and conservation (REDD+) implementation because; i) communities living adjacent to these forest have experience on forest management practices; iii), have realized benefits from the forest including climate change mitigation and iv) they have willingness to conserve the forests and have very high expectations to get benefit in terms of financial emanating from carbon trade. The present study investigated the present and future land use and cover changes for years 2020, 2030 up to 2040. A cross tabulation analysis method was used to detect and explain changes, while future land and cover change was established using Markov Chain-Cellular automata analysis. The state of land cover at time 2 was predicted by observing a state of land cover at time 1 using a matrix of transition probabilities from one land cover to every other land cover. Findings in Mgori forest predictions showed that cultivated, bushland and thickets land covers will increase by 2020 and thereafter remain constant while woodlands will decrease by 2020 and then remain constant. It can therefore be concluded that for areas already under CBFM what is required under REDD+ is to improve the management of agricultural land to sustain productivity as the room for much expansion of land is not warranted. This can be achieved through capacity building to farmers and other agricultural stakeholders through their local agricultural innovation systems.Available in the Proceedings of the International Conference on Reducing Climate Change Challenges through Forestry and Other Land Use PracticesClimate Change Impacts, Adaptation and Mitigation (CCIAM) Programme funded through the Norwegian embassy in Tanzani