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Backgroundandaims We quantified spatial variability in water storage and plant access to water in the rocky soils of a karst savanna dominated by Ashe juniper (Juniperus ashei) and honey mesquite (Prosopis glandulosa). Methods In a 25×25 m grid with 5-m node spacing, water content and bulk density profiles were measured to a depth of 1.6 m by a combination of time domain reflectometry, neutron thermalization and gamma ray densitometry. Changes in water content were used to infer recharge and plant uptake of soil water. Predawn water potentials of trees were sampled periodically to evaluate individual differences in water access. Results Pore volume and maximum water storage varied between 0.24 and 0.42 m 3 m −3 , and 198 to 431 mm, respectively, across the 36 individual profiles. Porosity accounted for 19and 20% and depth for 35and 61% of the variation in uptake and recharge, respectively. Predawn water potentials were consistently different among individual trees over multiple dry seasons. Conclusions Unequal water status among trees was consistent with the variability of recharge and uptake in the rooting zone, suggesting that trees cannot fully compensate for spatial variability in soil properties by roots foraging for water.

Woody plants are encroaching into grasslands and savannas of the karst Edwards Plateau, but their impacts on climate and hydrology are unclear because of high variability in soil depth and uncertainties about the contribution of water in fractured limestone to the water available to trees. Water use is controlled by available energy (AE) and its partitioning between latent (λE) and sensible (H) heat fluxes. We hypothesized that the partitioning of AE depends on soil depth, with greater depth leading to more λE and less H. We compared energy fluxes of a deep soil savanna with ~50% woody cover dominated by Ashe juniper (Juniperus ashei) and a shallow soil woodland dominated by live oak (Quercus virginiana) and juniper over a 5-year period, which included periods of unusually high rainfall and severe drought. Although AE was 7% higher in the woodland, λE was about 2% higher at the savanna over the 5-year study. Site differences in evapotranspiration were maximal during dry periods between rainfall events, suggesting greater storage of water at the savanna site. During periods of high rainfall, the impact of water storage limitations was minimal, and site differences in evapotranspiration were controlled mainly by AE and its partitioning into H. Both sites were characterized by rapid reductions in λE and reciprocal increases in H during drying cycles following rainfall, indicating that neither of these ecosystems had access to easily utilized sources of deep water. Copyright © 2012 John Wiley & Sons, Ltd.

Background Obtaining a diagnosis of developmental co-ordination disorder (DCD) is a long, inconsistent and frustrating journey for families, with apparently little awareness of DCD in schools or the medical community. Methods An online survey was completed by 1297 participants: parents (n = 501), teachers (n = 202), family/general physicians (n = 339) and paediatricians (n = 255). Results Only 20% of the sample had knowledge of DCD, with 41% of the paediatricians and 23% of family/general physicians familiar. Of participants who have awareness, only 11–59% have knowledge of the impact of DCD on social, emotional and physical health. Less than 30% of physicians have awareness of the secondary consequences. Few physicians diagnose DCD and less than one-third believe it is easy to make a diagnosis; this is in contrast to the fact that most parents report confidence in their physician's ability to make a timely diagnosis. Conclusions If less than one-half of physicians have knowledge of DCD and even fewer are knowledgeable of the secondary consequences of the condition, it is not surprising that DCD is infrequently diagnosed and that families need to search for support. This survey confirms observations that the condition is not well known and there is a need for greater awareness of DCD.

Goodenough Spring (Texas, USA) is a large spring near the border of the American state of Texas and the Mexican state of Coahuila, discharging into the international Amistad Reservoir on the river Rio Grande (Rio Bravo). Discharge was routinely measured from 1928 until 1968 to partition the flow of the river between the two countries in accordance with water-use treaties. Samples were analyzed for water-quality parameters in 1967–1968 prior to inundation under 45 m of Amistad Reservoir in 1968. Subsequently, discharge has been estimated indirectly by the International Boundary and Water Commission (IBWC). For the first direct measurements of the spring in 37 years, velocity and cross-sectional measurements were made and water samples collected in the summer of 2005 using advanced self-contained underwater breathing apparatus (SCUBA) techniques. Spring discharge was calculated at 2.03 m3 s–1, approximately one-half of the historical mean of 3.94 m3 s–1. In situ and laboratory analyses of samples for temperature, pH, dissolved oxygen, specific conductance, alkalinity, nitrate-nitrogen, dissolved solids, chloride, sulfate, fluoride, phosphorus, calcium, sodium, potassium, magnesium, and iron showed the water quality to be very good for human consumption and crop irrigation. Measurement values are relatively unchanged from those reported 37 years prior.

Eddy covariance measurements were begun in late April 2004 to quantify CO 2 exchange in a perennial C 3 /C 4 grassland on the Edwards Plateau near San Marcos, TX. Objectives were to document how net ecosystem exchange of CO 2 (NEE) and its components, gross photosynthesis (GPP) and ecosystem respiration ( R e ), vary on a seasonal and interannual basis, and to examine how environmental factors affect C exchange. Described here are the first 32 months of measurements. The grassland was intermittently grazed in 2004 and 2005, and heavily grazed during the spring and summer of 2006. Total rainfall from May through December 2004 was 1378 mm, well above the 858 mm annual mean, whereas rainfall in 2005 and 2006 was near normal. The grassland was dominated by C 4 grasses when measurements began, but C 3 grasses and forbs became dominant as the study progressed. The shift from a C 4 - to a C 3 -dominated ecosystem was accompanied by a 24% decline in light use efficiency. Water deficits were a frequent occurrence, even during 2004 when rainfall was high, causing large reductions in R e , GPP, and light use efficiency, and temporary shifts in the grassland from C sink to C source. Our measurements showed the grassland was a small C sink over the 32 months, gaining 170 g m −2 of C, due in large part to drought-induced suppression of R e during the winter of 2005–2006, and to a pulse of growth that occurred during the last 3 months of 2006. Total GPP and R e were 2081 and 1911 g m −2 , respectively. The grassland accumulated 1037 g m −2 of C during the daytime, and lost 867 g m −2 at night. Rates of C uptake were highest in the spring, and were higher when grazing was heaviest because growth of new leaves having a high photosynthetic efficiency, and reductions in R e , compensated for loss of leaf area.

Animals continuously release biogenic substances that vary in composition with physiological state. In aquatic systems, animals can gain insight about conditions or events upstream and alter their physiology and behavior to exploit this information. Here, we review observations on aquatic animals as diverse as snails, shrimp, fish, and frog tadpoles to probe the possibility that high-density aquaculture might generate chemical messages that cause conspecific or related individuals to reduce productive processes (growth, metamorphosis, ecdysis, reproduction) or even to sicken and die (loss of immunocompetence, anaphylaxis). The potential for ecological disruption logically is maximized under conditions that uncouple the parts of the system generating and receiving such signals—as would be the case when aquacultural effluents enter natural aquatic systems.

In this paper we give a categorical treatment of matrix Toda brackets, both in the preand post-compositional versions. Explicitly the setting in which we work is, a la Gabriel-Zisman, a 2-category with zeros. The development parallels that in the topological setting but with homotopy groups replaced by nullity groups of invertible 2-morphisms. A central notion is that of conjugation of 2-morphisms. Our treatment of matrix Toda brackets is carried forward to the point of establishing appropriate indeterminacies. 0. INTRODUCTION When P. Gabriel and M. Zisman wrote their book [3] they presented their subject (homotopy theory of simplicial sets via categories of fractions) from the most general point of view available going "back to the beginning of the theory ... in the hope of providing the reader with ... proofs which are easier or more conceptual than those already published." Their study of homotopy having begun in Chapter IV they set out in Chapter V "to give a standard and self-dual proof of various exact sequences occurring in Algebraic Topology ... the main idea is to construct an exact sequence in the category of pointed groupoids and then to reduce the study of a large class of 2-categories to the preceding one." They soon specialise to 2-categories ?1 which satisfy conditions A and B below: A. If x and y are two objects of 2', Hom sw(x, y) is a groupoid. B. There is an object o of 2' such that, for any object x of XP, Homr(o, x) and Homw(x, o) are isomorphic to the zero category Continuing in the spirit of Gabriel and Zisman the present paper is a contribution to an abstract theory of homotopy that assumes the existence of a 2-category &' satisfying only condition B. Indeed it can be regarded as sequel to a paper [8] by the third author which, in the setting of an arbitrary 2-category, studies the notion of homotopy equivalence and characterises the homotopy equivalences in various lax categories. Here the development parallels that in the topological setting but with track groups of the form 7r(EX, Y) or 7r(X, Q2Y) replaced by nullity groups of invertible 2-morphisms. A central notion is that of conjugation of 2-morphisms. This notion is available in any 2-category but does not seem to have been used previously. In fact when Received by the editors June 9, 1993. 1991 Mathematics Subject Classification. Primary 18D05, 55Q05, 55Q35. ?1995 American Mathematical Society

In this note we present a variant of bridging theorems in abstract homotopy theory which applies to the category of semisimplicial sets yielding bridging theorems for semisimplicial sets which might prove useful in semi-algebraic topology.

The distribution of lipoprotein species (LpA-I, LpA-I:A-II) in serum and within HDL subfractions (HDL2b, HDL2a, HDL3) was examined in 26 sedentary and 19 endurance trained normolipemic male individuals. The concentrations of lipids and apolipoproteins in serum and HDL subfractions and the concentrations of LpA-I and LpA-I:A-II were determined. Significant differences (Mann-Whitney-U-test) were found in serum concentrations of apoB (P0.05), apoA-II (P0.01) and LpA-I:A-II (P0.001). In HDL3 apoA-II concentration was significantly lower in the trained group (P0.05) but in HDL2 subclasses the concentrations of apoA-I and apoA-II did not differ between the groups. Despite similar concentrations of the two apolipoproteins, there were difference in the distribution of lipoprotein species within HDL2 subfractions. The concentrations of LpA-I did not differ, but the concentrations of LpA-I:A-II particles were higher in the trained group. Untrained and trained had similar concentrations of apoA-II (in HDL2b) but obviously more apoA-II containing particles and this leads to the assumption that within HDL2 of endurance trained individuals LpA-I:A-II particles have a lower apoA-II content compared with particles of untrained individuals. The data emphasize, that normolipemic individuals of different maximum oxygen uptake have a different distribution and composition of lipoprotein species (LpA-I, LpA-I:A-II).

In this paper we present comparison theorems in semicubical homotopy theory. Topological versions are more or less well known and have been obtained amongst others by A. DOLD ([6], [7]), I. M. JAMES ([11]), P. R. HEATH ([9]), S. P. LAM ([15]), and the first author ([2], [3]). A partially abstract approach has been given by the first author in [3]. We use operations on homotopy sets and the notion of CHEP (covering homotopy extension property).

A Kervaire diagram of group homomorphisms and pointed maps arising from a standard homotopy pullback Z of groupoid morphisms with common codomain is studied. The diagram yields two exact Mayer-Vietoris sequences that specialize in various ways. A classification theorem is obtained for the set of components of z. Applications are given to elementary group theory and to homotopy pair theory.

Der „Arzt fur Anasthesiologie“ oder kurz der „Anasthesist“1 unterscheidet sich in vielerlei Hinsicht von dem durch Tradition, Aufgabenstellung und rechtliche Einschatzung gepragten Bild des heutigen Arztes in der Ȕffentlichkeit. Dies gilt gleichermasen fur den Anasthesisten am Krankenhaus wie in freier Praxis. So hat der Jubilar, dem zu Ehren und aus aufrichter Dankbarkeit der Autor und Mitherausgeber dieser Festschrift diesen Beitrag konzipiert hat, immer wieder betont, das der Anasthesist Funktionsarzt ist.2 Indem er in erster Linie damit betraut ist, beim Operateur die zum Heileingriff notwendigen Anasthesieleistungen zu erbringen, grenzt er sich von dem Arzt als Diagnostiker, Therapeut und Hausarzt ab.