Quantum transport at the Dirac point: Mapping out the minimum conductivity from pristine to disordered graphene

The phase space for graphene's minimum conductivity $\sigma_\mathrm{min}$ is mapped out using Landauer theory modified for scattering using Fermi's Golden Rule, as well as the Non-Equilibrium Green's Function (NEGF) simulation with a Monte Carlo sampling over impurity distributions. The resulting `fan diagram' spans the range from ballistic to diffusive over varying aspect ratios ($W/L$), and bears several surprises. {The device aspect ratio determines how much tunneling (between contacts) is allowed and becomes the dominant factor for the evolution of $\sigma_{min}$ from ballistic to diffusive regime. We find an increasing (for $W/L>1$) or decreasing ($W/L<1$) trend in $\sigma_{min}$ vs. impurity density, all converging around $128q^2/\pi^3h\sim 4q^2/h$ at the dirty limit}. In the diffusive limit, the {conductivity} quasi-saturates due to the precise cancellation between the increase in conducting modes from charge puddles vs the reduction in average transmission from scattering at the Dirac Point. In the clean ballistic limit, the calculated conductivity of the lowest mode shows a surprising absence of Fabry-P\'{e}rot oscillations, unlike other materials including bilayer graphene. We argue that the lack of oscillations even at low temperature is a signature of Klein tunneling

An Analysis of Understanding of Traffic Signs among Drivers and Pedestrians in Dhaka, Bangladesh

This research demonstrates the percentage of drivers and pedestrians understanding the traffic sign in Dhaka, Bangladesh. The survey was conducted among 634 drivers inside and outside of Dhaka city. Moreover, 508 pedestrians participated in the survey within Dhaka city. In comparison, there were 863 male respondents and 279 female respondents among 1142 respondents. The survey took the form of multiple-choice questions that included the picture attached to each sign. However, the survey questionnaires included a few questions regarding driver gender, age, educational qualification, and driving experience. Similarly, the survey questionnaires for pedestrians had also been discussed questions regarding pedestrian gender, age, educational qualification, and job status. The overall traffic sign understanding of drivers was 68.68%. Moreover, the comprehensive traffic signs understanding of pedestrians was 64.5%. The findings showed that the drivers had a medium degree of understanding of the traffic sign’s meaning. However, the study results showed that efforts are needed to educate the drivers and pedestrians about the proper interpretation and reaction to traffic signals

AIR TEMPERATURE AND SUNLIGHT INTENSITY OF DIFFERENT GROWING PERIOD AFFECTS THE BIOMASS, LEAF COLOR AND BETACYANIN PIGMENT ACCUMULATIONS IN RED AMARANTH (AMARANTHUS TRICOLOR L.)

The objectives of this study were to determine the effects of daily air temperature and sunlight intensity variations on biomass production, leaf color and betacyanin accumulations in red amaranth (Amaranthus tricolor L.). For this purpose, two improved cultivars; BARI-1 and Altopati were grown in seven different period (from April to October, 2006) under vinyl house condition in the experimental facilities of Gifu University, Japan. The mean daily temperatures fluctuated from 18 (growing month- April) to 29ºC (August), while the mean sunlight intensities varied from 850 (October) to 1257 μmol m-2 S-1 (August). The highest biomass yield and betacyanin accumulation was obtained in the warmer growing period (July and August) at 28 to 29ºC mean air temperatures and 1240 to 1257 μmol m-2 S-1 sunlight intensity. At the warmer growing period red amaranth produced red leaves with high color index, which enhanced the betacyanin accumulations. The biomass yield and betacyanin accumulations were reduced significantly in the growing period/month April and October under low temperature regimes (mean air temperature 18 and 19ºC, respectively). However, growing period’s air temperature contributed more for biomass and betacyanin accumulations in red amaranth than sunlight intensity. Comparing two cultivars the biomass yield of BARI-1 was higher biomass yield than that of Altopati and Altopati highlighted with the higher betacyanin accumulations than that of BARI-1 in all growing period. Quantification of the effects of daily air temperature and sunlight intensity on biomass and betacyanin accumulation is important for growers producing these crops for fresh market and also optimize the best growing period. Therefore the influence of air temperatures and sunlight intensity should be considered while grown red amaranth for maximum yield with bioactive compounds like betacyanin and should be grown in between 28 to 29ºC air temperature and 1240 to 1257 μmol.m-2.S-1. of sunlight intensity

Venture capital on a shoestring: Bioventures’ pioneering life sciences fund in South Africa

<p>Abstract</p> <p>Background</p> <p>Since 2000, R&D financing for global health has increased significantly, with innovative proposals for further increases. However, although venture capital (VC) funding has fostered life sciences businesses across the developed world, its application in the developing world and particularly in Africa is relatively new. Is VC feasible in the African context, to foster the development and application of local health innovation?</p> <p>As the most industrially advanced African nation, South Africa serves as a test case for life sciences venture funding. This paper analyzes Bioventures, the first VC company focused on life sciences investment in sub-Saharan Africa. The case study method was used to analyze the formation, operation, and investment support of Bioventures, and to suggest lessons for future health venture funds in Africa that aim to develop health-oriented innovations.</p> <p>Discussion</p> <p>The modest financial success of Bioventures in challenging circumstances has demonstrated a proof of concept that life sciences VC can work in the region. Beyond providing funds, support given to investees included board participation, contacts, and strategic services. Bioventures had to be proactive in finding and supporting good health R&D.</p> <p>Due to the fund’s small size, overhead and management expenses were tightly constrained. Bioventures was at times unable to make follow-on investments, being forced instead to give up equity to raise additional capital, and to sell health investments earlier than might have been optimal. With the benefit of hindsight, the CFO of Bioventures felt that partnering with a larger fund might benefit similar future funds. Being better linked to market intelligence and other entrepreneurial investors was also seen as an unmet need.</p> <p>Summary</p> <p>BioVentures has learned lessons about how the traditional VC model might evolve to tackle health challenges facing Africa, including how to raise funds and educate investors; how to select, value, and support investments; and how to understand the balance between financial and social returns. The experience of the fund suggests that future health funds targeting ailments of the poor might require investors that accept health benefits as part of their overall “return.” Learning from Bioventures may help develop health innovation funding for sub-Saharan African that has combined health, financial, and economic development impacts.</p

Sundarban mangroves: diversity, ecosystem services and climate change impacts

The Bengal delta coast harboring the famous Sundarban mangroves is extremely vulnerable to climate change. Already, salinity intrusion, increasing cyclones and anomalies in rainfall, and temperature, are causing many social and livelihood problems. However, our knowledge on the diversified climate change impacts on Sundarban ecosystems services, providing immense benefits, including foods, shelters, livelihood, and health amenities, is very limited. Therefore, this article has systematically reviewed the major functional aspects, and highlights on biodiversity, ecosystem dynamics, and services of the Sunderban mangroves, with respect to variations in climatic factors. The mangrove ecosystems are highly productive in terms of forest biomass, and nutrient contribution, especially through detritus-based food webs, to support rich biodiversity in the wetlands and adjacent estuaries. Sundarban mangroves also play vital role in atmospheric CO2 sequestration, sediment trapping and nutrient recycling. Sea level rise will engulf a huge portion of the mangroves, while the associated salinity increase is posing immense threats to biodiversity and economic losses. Climate-mediated changes in riverine discharge, tides, temperature, rainfall and evaporation will determine the wetland nutrient variations, influencing the physiological and ecological processes, thus biodiversity and productivity of Sundarban mangroves. Hydrological changes in wetland ecosystems through increased salinity and cyclones will lower the food security, and also induce human vulnerabilities to waterborne diseases. Scientific investigations producing high resolution data to identify Sundarban‟s multidimensional vulnerabilities to various climatic regimes are essential. Sustainable plans and actions are required integrating conservation and climate change adaptation strategies, including promotion of alternative livelihoods. Thus, interdisciplinary approaches are required to address the future climatic disasters, and better protection of invaluable ecosystem services of the Sunderban mangroves.Fil: Neogi, Sucharit Basu. Coastal Development Partnership; Bangladesh. Osaka Prefecture University; Japón. Leibniz Center for Tropical Marine Ecology GmbH; AlemaniaFil: Dey, Mouri. University of Chittagong; BangladeshFil: Lutful Kabir, S. M.. Bangladesh Agricultural University; BangladeshFil: Masum, Syed Jahangir H.. Coastal Development Partnership; BangladeshFil: Kopprio, Germán Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Leibniz Center for Tropical Marine Ecology GmbH; AlemaniaFil: Yamasaki, Shinji. Osaka Prefecture University; JapónFil: Lara, Ruben Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentin

Effect of Advertisement on Purchasing Energy Drink in Dhaka City of Bangladesh

Public announcement intended to promote the sale, purchase or rental of a product or service to advance a cause or idea or to bring about some other effect desired by the advertiser, for which transmission time has been given to the advertiser for remuneration or similar consideration. The consumer durables usually calls for a greater exchange and hence the consumer decision-making process turns into a comparative critical evaluation method before the purchase is made; the first moving consumers good (FMCG) do not follow the same procedure in reaching at the purchase decision. Failure to address the advertising communication tools accordingly is wastage of valuable time, money, effort as well as other resources. For instances, communicating through an ineffective media or otherwise failing to reach the target segment is wastage of resources along with loss of sales as well as other favorable consequences. So that this paper tries to identify the advertisement effectiveness of energy drinks in different media on the buying decision among the peoples of Dhaka in Bangladesh. In order to reach the study objectives convenience/purposive sampling has been employed and sample is selected from different shopping mall of different areas of Dhaka city. The results of this study show that advertisement has great influence in expanding Energy drink Company. So producer should spend huge amount of money in advertisement and also should prepare the advertisement in such way that people of all classes are attracted of that advertisement and the most effective media is TV. Keywords: Energy Drink, Advertisement, Dhaka City, Banglades