Tanzanian forest tree plot diversity and elevation

Observed variation in species richness on ecological gradients and between regions has attracted several different explanations. Climatic factors, such as energy availability, precipitation and mean annual temperature, are frequently cited to explain differences in species richness (Wright et al. 1993). The relative amount of variation in these variables may be of importance as well as absolute values (Stevens 1989, 1992). Alternatively, the history of colonization and extirpation have been used to explain regional variation in diversity (Guo et al. 1998; Latham & Ricklefs 1993a, b). Area is an important factor, for example on an elevational gradient the tops of mountains are not only cooler than the bottoms, but they are also much smaller (Rahbek 1997)

Lower bounds for adaptive linearity tests

Linearity tests are randomized algorithms which have oracle access to the truth table of some function f, and are supposed to distinguish between linear functions and functions which are far from linear. Linearity tests were first introduced by (Blum, Luby and Rubenfeld, 1993), and were later used in the PCP theorem, among other applications. The quality of a linearity test is described by its correctness c - the probability it accepts linear functions, its soundness s - the probability it accepts functions far from linear, and its query complexity q - the number of queries it makes. Linearity tests were studied in order to decrease the soundness of linearity tests, while keeping the query complexity small (for one reason, to improve PCP constructions). Samorodnitsky and Trevisan (Samorodnitsky and Trevisan 2000) constructed the Complete Graph Test, and prove that no Hyper Graph Test can perform better than the Complete Graph Test. Later in (Samorodnitsky and Trevisan 2006) they prove, among other results, that no non-adaptive linearity test can perform better than the Complete Graph Test. Their proof uses the algebraic machinery of the Gowers Norm. A result by (Ben-Sasson, Harsha and Raskhodnikova 2005) allows to generalize this lower bound also to adaptive linearity tests. We also prove the same optimal lower bound for adaptive linearity test, but our proof technique is arguably simpler and more direct than the one used in (Samorodnitsky and Trevisan 2006). We also study, like (Samorodnitsky and Trevisan 2006), the behavior of linearity tests on quadratic functions. However, instead of analyzing the Gowers Norm of certain functions, we provide a more direct combinatorial proof, studying the behavior of linearity tests on random quadratic functions..

The Scope of the Truthmakers Requirement

Truths require truthmakers, many think. In this paper I will discuss the scope of this requirement. Truthmaker maximalism is the claim that, necessarily, all truths require truthmakers. I shall argue against this claim. I shall argue against it on the basis of its implications. I shall first consider its implications when applied to synthetic, contingent propositions. If the truthmaker requirement applies to these propositions, so I shall argue, it is not possible for there to be nothing, and it is not possible for any (possibly) accompanied entity to exist on its own. I shall then consider its implications when applied to modal propositions, specifically those concerning possible existence. I shall argue that if the truthmaker requirement applies to such propositions, then there can be no relation which is equivalent to metaphysical explanation, which – I shall suggest – amounts to a denial of the existence of grounding

Elevational and latitudinal changes in tree associations and diversity in the Eastern Arc mountains of Tanzania

A total of 200 variable-area plots covering 20 3 ha containing 4000 trees with a basal area of 921 4 m2 were assessed over a combined elevational range of 410-2180 m in the moist forests of three Tanzanian Eastern Arc mountains: West Usambara, Nguru and Udzungwa. Plot data were ordinated on the basis of species presence/absence, frequency and basal area Axis 1 of ordinations based on species presence/absence are correlated with elevation Axis 1 of the frequency-weighted ordination was correlated with elevation in the Nguru and Udzungwa mountains, but plots from the West Usambara showed a rainfall-related discontinuity Axis 1 of the West Usambara basal area-weighted ordination showed evidence of long-term dynamics of Ocotea usambarensis and in the Udzungwa mountains was determined by presence of Parinari excelsa Plot diversity was not correlated with elevation or latitude, but was lower in disturbed, low rainfall or more seasonal forest. Stem density was positively correlated with elevation and was greater on ridge tops than valley sides and valley bottom

Continuous change in Tanzanian moist forest tree communities with elevation

Although some studies in tropical forests suggest the existence of elevational discontinuities, zones or critical altitudes in floristic composition (briefly reviewed by Lovett 1996) two data sets from the Usambara mountains of Tanzania independently show a continuous elevational change in moist forest large tree communities (Hamilton et al. 1989, Lovett 1996). However, one data set is from the West Usambara mountains (Lovett 1996) and the other is from the East Usambara (Hamilton et al. 1989). The junction of the two data sets at around 1000–1200 m in elevation is regarded as a critical altitude (Lovett 1996), and so neither conclusively prove continuity over the entire elevational range of the forests. The two data sets were collected using the same methodology, the twenty-tree variable-area plotless technique (Hall 1991), and together constitute a transect covering nearly 2 km in elevation. They are combined here to test for continuity in change in forest large-tree communities from lowland to upper montane forest types

MDS matrices over small fields: A proof of the GM-MDS conjecture

An MDS matrix is a matrix whose minors all have full rank. A question arising in coding theory is what zero patterns can MDS matrices have. There is a natural combinatorial characterization (called the MDS condition) which is necessary over any field, as well as sufficient over very large fields by a probabilistic argument. Dau et al. (ISIT 2014) conjectured that the MDS condition is sufficient over small fields as well, where the construction of the matrix is algebraic instead of probabilistic. This is known as the GM-MDS conjecture. Concretely, if a $k \times n$ zero pattern satisfies the MDS condition, then they conjecture that there exists an MDS matrix with this zero pattern over any field of size $|\mathbb{F}| \ge n+k-1$. In recent years, this conjecture was proven in several special cases. In this work, we resolve the conjecture

The WTO: A Train Wreck in Progress?

This article argues that the WTO entrenches an asymmetrical, non-reciprocal trading system that benefits multi-national corporations especially, at the expense of industrial workers, farmers, and a wide range of business enterprises. It argues that the WTO doesn\u27t deserve to survive in its present, unbalanced, and unsustainable form, and that it is doubtful that its voting regime, accumulated asymmetries, and overall rigidity can be overhauled. The author posits that bilateral and regional trade bargaining will become increasingly important and that world market forces are likely to bypass, and perhaps overwhelm, the WTO

Juror Internet Misconduct: A Survey of New Hampshire Superior Court Judges

[Excerpt] “The Constitution guarantees criminal defendants the right to a fair trial before an impartial jury and the right to confront the evidence against them. When a juror improperly accesses the Internet during a criminal trial, the defendant is denied these constitutional rights. The problem of outside information entering the courtroom is as old as our judicial system. As early as 1907, Justice Holmes observed that, “The theory of our [criminal justice] system is that the conclusions to be reached in a case will be induced only by evidence and argument in open court, and not by any outside influence, whether of private talk or public print.” Yet in recent years, the issue of juror misconduct has been brought to the forefront by striking examples of jurors seeking information on the Internet, outside of the evidence presented in court. This Note examines the prevalence of Internet-related juror misconduct in the New Hampshire Superior Court and the efforts of Superior Court judges to detect and prevent such misconduct. I conducted a survey of New Hampshire Superior Court judges regarding their experience with juror Internet misconduct and solicited their feedback about a sample jury instruction. I have incorporated their feedback into a proposed set of jury instructions specifically targeted at reducing juror Internet misconduct.