Periods of second kind differentials of (n,s)-curves

For elliptic curves, expressions for the periods of elliptic integrals of the second kind in terms of theta-constants, have been known since the middle of the 19th century. In this paper we consider the problem of generalizing these results to curves of higher genera, in particular to a special class of algebraic curves, the so-called $(n,s)$-curves. It is shown that the representations required can be obtained by the comparison of two equivalent expressions for the projective connection, one due to Fay-Wirtinger and the other from Klein-Weierstrass. As a principle example, we consider the case of the genus two hyperelliptic curve, and a number of new Thomae and Rosenhain-type formulae are obtained. We anticipate that our analysis for the genus two curve can be extended to higher genera hyperelliptic curves, as well as to other classes of $(n,s)$ non-hyperelliptic curves.Comment: 21 page

The Flora of Brush Creek Canyon State Preserve

Brush Creek Canyon State Preserve is a scenic natural area in Fayette County, Iowa. The preserve contains steep, wooded ravines; tall, vertical outcrops of dolomitic limestone; clear streams; cascades area; and cool springs. These habitats support a variety of native plant communities, resulting in a rich flora of at least 268 species of vascular plants. Man-made disturbance is minimal, and there are several species of rare plants that increase the importance of the preserve

The Remnant Prairie Flora in Northeast lowa

A list of 360 species of vascular plants inhabiting prairie remnants in northeast Iowa is presented. Descriptions and locations of the prairie remnants are also included

History of Studies on the Iowa Vascular Flora

Although a manual of the vascular plants of Iowa has yet to be written, many botanists have contributed to a thorough floristic survey of the state, and most of the difficult plant families have been studied taxonomically. The number of vascular plant species is estimated at over 1,800. It would probably require five or more years of concentrated effort to produce an accurate, comprehensive manual of the Iowa flora. A listing of 238 selected references on the Iowa vascular flora is presented

Biobank, a Computerized Data Storage and Processing System for the Vascular Flora of Iowa

BIOBANK is an electronic data processing (EDP) system for storing and processing the accumulated data on the vascular flora of Iowa. This computerized system was designed as a tool to facilitate floristic research by systematists who may have had little or no training in computer operation. Thus, a minimum of coding is used; the usual kinds of information are entered into the system and the printouts are in traditional formats. The programs, which together form the BIOBANK system, are written in the PL/1 programming language. The data processed by the system can be: 1) of varying lengths; 2) stored in the data bank; 3) modified or corrected; 4) merged as desired; and 5) retrieved in a variety of ways by the search and store facilities of the system. Because of the flexibility of the BIOBANK system, it can be readily adapted to process other kinds of data

The Flora of Iowa Revived

Research on the flora of Iowa is being renewed by Dr. Robert F. Thorne and the author. A manual of the vascular plants of the state is planned for the near future. Some revisionary study of Iowa taxa needs to be completed first, but it is hoped that interested botanists will assist in the task. Although there are a few areas that need additional intensive collecting, the state has been quite well surveyed, floristically, and there is need to integrate the information into a usable publication

Improved Dynamic Predictions from Joint Models of Longitudinal and Survival Data with Time-Varying Effects using P-splines

In the field of cardio-thoracic surgery, valve function is monitored over time after surgery. The motivation for our research comes from a study which includes patients who received a human tissue valve in the aortic position. These patients are followed prospectively over time by standardized echocardiographic assessment of valve function. Loss of follow-up could be caused by valve intervention or the death of the patient. One of the main characteristics of the human valve is that its durability is limited. Therefore, it is of interest to obtain a prognostic model in order for the physicians to scan trends in valve function over time and plan their next intervention, accounting for the characteristics of the data. Several authors have focused on deriving predictions under the standard joint modeling of longitudinal and survival data framework that assumes a constant effect for the coefficient that links the longitudinal and survival outcomes. However, in our case this may be a restrictive assumption. Since the valve degenerates, the association between the biomarker with survival may change over time. To improve dynamic predictions we propose a Bayesian joint model that allows a time-varying coefficient to link the longitudinal and the survival processes, using P-splines. We evaluate the performance of the model in terms of discrimination and calibration, while accounting for censoring