Flying a quadrotor helicopter requires at least a means for stabilization control. Although efficiently stabilizing a quadrotor is itself an extensive research field, adding autonomous control poses even more challenging problems: the underlying quadrotor platform must provide sufficiently precise sensors with high update rates, the mechanical parts should not incur large update delays, and the...

There are many methods for constructing prediction intervals for differences in observations. This document will explain several of these methods in the context of different models using data from a kiwi yield experiment as an example. 1. KIWI DATA In an experiment (discussed in more detail in class), kiwi yields were measured in a designed experiment. There were three blocks (north, east, and ...

Coffee agroecosystems are critical to the success of conservation efforts in Latin America because of their ecological and economic importance. Coffee certification programs may offer one way to protect biodiversity and maintain farmer livelihoods. Established coffee certification programs fall into three distinct, but not mutually exclusive categories: organic, fair trade, and shade. The resul...

The aim of this study is to investigate the effects of two important factors: light and water availability on the leaf characteristics and the growth of plants. Seedlings of Quercus suber were grown under controlled conditions (greenhouse) with three light treatments (100, 27 and 3 % of incident light, open, shade and deep shade; respectively) and with daily irrigation. Since middle spring, one...

One of the main drivers of tropical forest loss is their conversion to oil palm, soy or cacao plantations with low biodiversity and greatly reduced carbon storage. Southeast Asian cacao plantations are often established under shade tree cover, but are later converted to non-shaded monocultures to avoid resource competition. We compared three co-occurring cacao cultivation systems (3 replicate s...

First, we have to ask, who are these people? And there’s no easy answer. These are not well-defined groups with membership lists. And their activities have spawned many imitators and fellowtravellers. There are also some distinctions between the groups defined by the ‘members’ themselves. This makes labels difficult: ‘hacktivists’, ‘activists’, ‘hackers’, ‘members’ – even the word ‘group’ itsel...

The current crisis in the coffee market provides an opportunity to explore alternative markets. In Latin America, coffee is traditionally produced under a diverse and dense canopy of shade trees. The structural and floristic diversity contained therein harbors a high biodiversity of associated organisms. The recent trend of reducing this shade cover so as to increase production raises concerns ...

In a recent issue of Conservation Biology, Rappole et al. (2003) argued that promoting shade-grown coffee threatens some forest ecosystems (particularly highland pineoak forests) and discussed reasons why the shade coffee movement is misleading in terms of biodiversity conservation. Here, we argue that in the larger global agricultural context, and if promoted correctly, shade coffee does not p...

OBJECTIVE This in vitro study evaluated the effect of two different shades of resin cement (RC- A1 and A3) layer on color change, translucency parameter (TP), and chroma of low (LT) and high (HT) translucent reinforced lithium disilicate ceramic laminates. MATERIAL AND METHODS One dual-cured RC (Variolink II, A1- and A3-shade, Ivoclar Vivadent) was applied to 1-mm thick ceramic discs to creat...