Galactic Effects on Habitability

The galactic environment has been suspected to influence planetary habitability in many ways. Very metal-poor regions of the Galaxy, or those largely devoid of atoms more massive than H and He, are thought to be unable to form habitable planets. Moreover, if such planets do form, the young system is subjected to close stellar passages while it resides in its stellar birth cluster. Various potential hazards remain after clusters disperse. For instance, central galactic regions may present risks to habitability via nearby supernovae, gamma ray bursts (GRBs), and frequent comet showers. In addition, planets residing within very wide binary star systems are affected by the Galaxy, as local gravitational perturbations from the Galaxy can increase the binary's eccentricity until it destabilizes the planets it hosts. Here we review the most recent work on the main galactic influences over planetary habitability. Although there must be some metallicity limit below which rocky planets cannot form, recent exoplanet surveys show that they form around stars with a very large range of metallicities. Once formed, the probability of star clusters destabilizing planetary systems only becomes high for rare, extremely long-lived clusters. Regarding threats to habitability from supernovae, GRBs, and comet showers, many recent studies suggest that their hazards are more limited than originally thought. Finally, denser regions of the Galaxy enhance the threat that very wide binary companions pose to planetary habitability, but the probability that a very wide binary star disrupts habitability will always be substantially below 100% for any environment. While some Milky Way regions must be more hospitable to habitable planets than others, it is difficult to state that habitable planets are confined to any well-defined region of the Galaxy or that any other particular region of the Galaxy is uninhabitable.Comment: Invited review chapter, accepted for publication in the "Handbook of Exoplanets"; 19 pages; 2 figure

Ecosystem services from Southern African woodlands and their future under global change

Miombo and mopane woodlands are the dominant land cover in southern Africa. Ecosystem services from these woodlands support the livelihoods of 100 M rural people and 50 M urban dwellers, and others beyond the region. Provisioning services contribute $9 ± 2 billion yr(−1) to rural livelihoods; 76$780 M. Woodlands support much of the region's agriculture through transfers of nutrients to fields and shifting cultivation. Woodlands store 18–24 PgC carbon, and harbour a unique and diverse flora and fauna that provides spiritual succour and attracts tourists. Longstanding processes that will impact service provision are the expansion of croplands (0.1 M km(2); 2000–2014), harvesting of woodfuels (93 M tonnes yr(−1)) and changing access arrangements. Novel, exogenous changes include large-scale land acquisitions (0.07 M km(2); 2000–2015), climate change and rising CO(2). The net ecological response to these changes is poorly constrained, as they act in different directions, and differentially on trees and grasses, leading to uncertainty in future service provision. Land-use change and socio-political dynamics are likely to be dominant forces of change in the short term, but important land-use dynamics remain unquantified. This article is part of the themed issue ‘Tropical grassy biomes: linking ecology, human use and conservation’

Vampires in the village Žrnovo on the island of Korčula: following an archival document from the 18th century

Središnja tema rada usmjerena je na raščlambu spisa pohranjenog u Državnom arhivu u Mlecima (fond: Capi del Consiglio de’ Dieci: Lettere di Rettori e di altre cariche) koji se odnosi na događaj iz 1748. godine u korčulanskom selu Žrnovo, kada su mještani – vjerujući da su se pojavili vampiri – oskvrnuli nekoliko mjesnih grobova. U radu se podrobno iznose osnovni podaci iz spisa te rečeni događaj analizira u širem društvenom kontekstu i prate se lokalna vjerovanja.The main interest of this essay is the analysis of the document from the State Archive in Venice (file: Capi del Consiglio de’ Dieci: Lettere di Rettori e di altre cariche) which is connected with the episode from 1748 when the inhabitants of the village Žrnove on the island of Korčula in Croatia opened tombs on the local cemetery in the fear of the vampires treating. This essay try to show some social circumstances connected with this event as well as a local vernacular tradition concerning superstitions

Satellite-Based Estimation of Water Discharge and Runoff in the Magdalena River, Northern Andes of Colombia

Satellite-derived data provide important information about river characteristics such as channel geometry, water surface area, water levels, and floodplain extension (Rokni et al. 2015; Schumann and Moller 2015; Smith 1997

The effect of flood disaster on construction sector’s GDP growth in Malaysia

Flood disasters have incurred remarkable costs to humans and the economy. Floods affect not only the local but also the national and world economies. However, the impact of floods on the construction sector’s GDP growth in Malaysia is not known. The purpose of this chapter is to analyse the effects of flood disaster on the construction sector’s GDP growth in Malaysia using time series data for the period 1960–2013. In addition, the chapter also explores the existence of short-run and long-run relationships between the construction sector’s GDP growth and flood variables in the case of Malaysia. To achieve the objectives, the study employed the autoregressive distributed lag (ARDL) method and the error correction model (ECM) in examining the long-run and the short-run relationships, respectively. In addition, the augmented Dickey–Fuller, Phillips–Perron and Kwiatkowski–Phillips–Schmidt–Shin unit root tests were used to examine the stationarity of the series. The results show that flood size and flood damage influence the construction sector’s GDP growth the most in the short and long run, respectively. Several policy implications arise from the results. First, there is a need to develop a new method of construction so that the infrastructures and buildings are durable, as flood disasters cannot be prevented. Well-developed infrastructures and buildings are able to prevent massive damages in the long run. Furthermore, the construction sector should prepare sufficient stock of items such as basic metals to prevent temporary setback in the short run