Opening the species box: what parsimonious microscopic models of speciation have to say about macroevolution.

In the last two decades, lineage-based models of diversification, where species are viewed as particles that can divide (speciate) or die (become extinct) at rates depending on some evolving trait, have been very popular tools to study macroevolutionary processes. Here, we argue that this approach cannot be used to break down the inner workings of species diversification and that "opening the species box" is necessary to understand the causes of macroevolution, but that too detailed speciation models also fail to make robust macroevolutionary predictions. We set up a general framework for parsimonious models of speciation that rely on a minimal number of mechanistic principles: (a) reproductive isolation is caused by excessive dissimilarity between genotypes; (b) dissimilarity results from a balance between differentiation processes and homogenizing processes; and (c) dissimilarity can feed back on these processes by decelerating homogenization.

0-1 Laws for Pattern Occurrences in Phylogenetic Trees and Networks.

In a recent paper, the question of determining the fraction of binary trees that contain a fixed pattern known as the snowflake was posed. We show that this fraction goes to 1, providing two very different proofs: a purely combinatorial one that is quantitative and specific to this problem; and a proof using branching process techniques that is less explicit, but also much more general, as it applies to any fixed patterns and can be extended to other trees and networks. In particular, it follows immediately from our second proof that the fraction of d-ary trees (resp.

Two patients with allergy to celery - Possible role of carbohydrate determinants and difference between seeds and tuber allergenicity.

Vegetables provide important nutrients but can also induce allergic symptoms. Celery tuber allergy frequently occurs in Central European countries and can cause allergic reactions including fatal anaphylactic shocks. There is little information about allergen content in seeds.

Occupational Performance and Hand Function in People With Parkinson's Disease After Participation in Lee Silverman Voice Treatment (LSVT) BIG®.

Importance: People with Parkinson's disease (PD) experience motor and functional impairment that can negatively affect daily living and participation.

Objective: To examine the occupational performance and hand function outcomes of people with PD who participated in a Lee Silverman Voice Treatment (LSVT) BIG® program.

Design: Retrospective record review.