Be Careful What You Wish For? Reducing Inequality in the Twenty-First Century

A review of Walter Scheidel, The Great Leveler: Violence and the History of Inequality from the Stone Age to the Twenty-First Century

The Hydrochemistry of Groundwater in Some Communities in the Ayensu River Basin in the Central Region of Ghana

Hydrochemical analysis of groundwater samples in some communities in the Ayensu river basin of the central Region of Ghana was used to establish the hydrochemistry of the study area. The methodology consisted of physicochemical sampling and laboratory analysis of groundwater resources in the Basin and basic statistical analysis of the laboratory results. Generally, the groundwater is weakly acidic with a mean pH value of 6.32, had high electrical conductivity and TDS values in the range, 256.4 µS cm-1 to 2313.3 µS cm-1 and 101.7 mg/L to 1247.0 mg/L respectively. The groundwater in the area is undersaturated with respect to carbonate phases and is fresh except for one borehole at Gyangyanadze which has TDS value of 1247.0 mg/L considered as saline water.  The dominant water types in the study area are Na- Cl, Ca- Mg - Cl and Ca - Mg - SO4. The groundwater is to a large extent potable. However, approximately 13% of the groundwater samples had chloride concentrations slightly exceeding the respective WHO maximum acceptable limits for drinking water. Approximately 43%, 16% and 10% respectively of the water samples had Al3+, Fe2+ and Cd2+ concentrations above the respective WHO maximum acceptable limit for drinking water.  Silicate mineral weathering is probably the main process through which major ions enter the groundwater. Keywords:Groundwater quality  hydrochemistry  silicate weathering  Central Region  Ghana 

Some Simple Economics of Crowdfunding

It is not surprising that the financing of early-stage creative projects and ventures is typically geographically localized since these types of funding decisions are usually predicated on personal relationships and due diligence requiring face-to-face interactions in response to high levels of risk, uncertainty, and information asymmetry. So, to economists, the recent rise of crowdfunding - raising capital from many people through an online platform - which offers little opportunity for careful due diligence and involves not only friends and family but also many strangers from near and far, is initially startling. On the eve of launching equity-based crowdfunding, a new market for early-stage finance in the U.S., we provide a preliminary exploration of its underlying economics. We highlight the extent to which economic theory, in particular transaction costs, reputation, and market design, can explain the rise of non-equity crowdfunding and offer a framework for speculating on how equity-based crowdfunding may unfold. We conclude by articulating open questions related to how crowdfunding may affect social welfare and the rate and direction of innovation

Recharging Metode Pembelajaran Kewirausahaan Berbasis Multimedia untuk Guru SD di Desa Tieng Wonosobo

Perkembangan ilmu dan teknologi semakin mendorong USAha-USAha ke arah pembaharuan dalam memanfaatkan hasil-hasil teknologi dalam pelaksanaan pembelajaran. Guru (pengajar) dalam mengikuti perkembangan teknologi ini diharapkan dapat menggunakan alat atau bahan pendukung proses pembelajaran, dari alat yang sederhana sampai alat yang canggih (sesuai dengan perkembangan dan tuntutan jaman). Pengabdian ini dilaksanakan dengan peserta pelatihan yaitu guru di SD Ma'arif dan Muhammadiyah Tieng. Materi pelatihan adalah konsep kewirausahaan yang dibuat dalam aplikasi video multimedia. Analisis situasi menunjukkan pembelajaran kewirausahaan bisa diterapkan di hamper semua bidang studi. Muatan dan konsep kewirausaan dapat diterapkan pada mata pelajaran yang menjadi kurikulum di SD Ma'arif dan Muhammadiyah. Namun demikian metode pembelajaran yang digunakan masih sederhana. Dengan pelatihan ini peserta diajarkan membuat media ajar yang menggunakan video multimedia dengan aplikasi Software Pinacle. Peserta pelatihan menunjukkan respon antusias dan hasil pelatihan menunjukkan hasil beberapa peserta pelatihan mampu menagkap dan mengaplikasikannya

Physico-Chemical Analysis of Surface and Groundwater in the Ayensu River Basin in the Central Region of Ghana

The hydrochemistry of the Ayensu river basin in the central Region of Ghana has been established. The methodology consisted of physicochemical sampling and laboratory analysis of both groundwater and surface water resources in the Basin and basic statistical analysis of the laboratory results.. Generally, the groundwater is weakly acidic with a mean pH value of 6.33±0.01, had high electrical conductivity and TDS values in the range, 297.65 to 6011.0 and 100.85 to 2746.0 respectively. Three main hydrochemical facies have been identified in the basin. These are Na- Cl, Ca- Mg - Cl and Ca - Mg - SO4 water types. Groundwater is to a large extent potable. However, approximately 24% and 22% respectively of groundwater samples had chloride and sulphate concentrations slightly exceeding the respective WHO maximum acceptable limits for drinking water. The concentrations of aluminium, iron and manganese were the only minor ions that significantly exceeded their respective detection limits. Nearly 43% of the groundwater samples had the Al3+ concentrations exceeding the WHO acceptable limit of 0.2 mg/l for drinking water, which reflects the acidic nature of the groundwater. The main geochemical process influencing the hydrochemistry of the Ayensu river basin is mineral dissolution. Keywords Groundwater quality, hydrochemistry, Mineral dissolution, Central Region Ghana. 

Approaches to Preparing Rhodamine-Dyed Monolithic Silica Aerogels

Silica aerogels are unique nanoporous materials that can be used in a variety of applications. Silica aerogels are attractive for window applications as they are monolithic, thermally insulating, and extremely lightweight. They also can be made transparent or translucent. Aerogels can be made using a variety of methods; in this work, a rapid supercritical extraction method (RSCE) is employed. Although typically translucent, silica aerogels can have dyes incorporated within them to create aerogels of a variety of colors. We are investigating the usage of dyed monolithic silica aerogels in window applications to improve aesthetic effects. However, the high temperatures and pressures required for the RSCE process can lead to dye degradation. In this presentation, we demonstrate how to incorporate Rhodamine 6B, Rhodamine B, and Fluorescein into monolithic silica aerogels. Rhodamine B experiences thermal degradation during monolithic aerogel synthesis. Adjusting processing parameters, including temperature and pressure, can minimize thermal degradation while ensuring the structural integrity of the aerogel. Ultraviolet radiation can also lead to dye degradation, which would be problematic for aerogels in a window application. Future work will focus on spectroscopic characterization of the dyed aerogel monoliths

High temperature condensate clouds in super-hot Jupiter atmospheres

Deciphering the role of clouds is central to our understanding of exoplanet atmospheres, as they have a direct impact on the temperature and pressure structure, and observational properties of the planet. Super-hot Jupiters occupy a temperature regime similar to low mass M-dwarfs, where minimal cloud condensation is expected. However, observations of exoplanets such as WASP-12b (Teq ~ 2500 K) result in a transmission spectrum indicative of a cloudy atmosphere. We re-examine the temperature and pressure space occupied by these super-hot Jupiter atmospheres, to explore the role of the initial Al- and Ti-bearing condensates as the main source of cloud material. Due to the high temperatures a majority of the more common refractory material is not depleted into deeper layers and would remain in the vapor phase. The lack of depletion into deeper layers means that these materials with relatively low cloud masses can become significant absorbers in the upper atmosphere. We provide condensation curves for the initial Al- and Ti-bearing condensates that may be used to provide quantitative estimates of the effect of metallicity on cloud masses, as planets with metal-rich hosts potentially form more opaque clouds because more mass is available for condensation. Increased metallicity also pushes the point of condensation to hotter, deeper layers in the planetary atmosphere further increasing the density of the cloud. We suggest that planets around metal-rich hosts are more likely to have thick refractory clouds, and discuss the implication on the observed spectra of WASP-12b.Comment: Accepted for publication in MNRAS, 10 pages, 1 table, 5 figure

Slack Time and Innovation

The relationship between slack resources and innovation is complex, with the literature linking slack to both breakthrough innovations and resource misallocation. We reconcile these conflicting views by focusing on a novel mechanism: the role slack time plays in the endogenous allocation of time and effort to innovative projects. We develop a theoretical model that distinguishes between periods of high- (work weeks) versus low- (break weeks) opportunity costs of time. Low-opportunity cost time during break weeks may induce (1) lower quality ideas to be developed (a selection effect); (2) more effort to be applied for any given idea quality (an effort effect); and (3) an increase in the use of teams because scheduling is less constrained (a coordination effect). As a result, the effect of an increase in slack time on innovative outcomes is ambiguous, because the selection effect may induce more low-quality ideas, whereas the effort and coordination effect may lead to more high-quality, complex ideas. We test this framework using data on college breaks and on 165,410 Kickstarter projects across the United States. Consistent with our predictions, during university breaks, more projects are posted in the focal regions, and the increase is largest for projects of either very high or very low quality. Furthermore, projects posted during breaks are more complex, and involve larger teams with diverse skills. We discuss the implications for the design of policies on slack time

The Geography of Crowdfunding

Perhaps the most striking feature of "crowdfunding" is the broad geographic dispersion of investors in small, early-stage projects. This contrasts with existing theories that predict entrepreneurs and investors will be co-located due to distance-sensitive costs. We examine a crowdfunding setting that connects artist-entrepreneurs with investors over the internet for financing musical projects. The average distance between artists and investors is about 3,000 miles, suggesting a reduced role for spatial proximity. Still, distance does play a role. Within a single round of financing, local investors invest relatively early, and they appear less responsive to decisions by other investors. We show this geography effect is driven by investors who likely have a personal connection with the artist-entrepreneur ("family and friends"). Although the online platform seems to eliminate most distance-related economic frictions such as monitoring progress, providing input, and gathering information, it does not eliminate social-related frictions.