Nutrients and water level fluctuations: A study of three aquatic plants

Water holes characteristic of the middle sections of fragmented, lowland, semi‐arid rivers act as refuge areas for biota during low flow and drought. However, river regulation and catchment development has altered the hydrological and nutrient status of these refuges. A series of artificial ponds were used to imitate these habitats and experiments were designed to determine whether stochastically fluctuating water levels with maximum amplitude of 65 cm would counteract the influence of nutrient enrichment on the growth of three key aquatic plant species. The species (Cyperus gymnocaulos, Triglochin procerum and Typha domingensis) represented different functional groups that inhabit contrasting zones across the elevation gradient. Each species was grown at a different elevation within the experiment reflecting each species' elevation preference and supplied with the equivalent to 0, 10 or 30 g N m^?2 year^?1. Under a static water regime nutrient enrichment doubled the total biomass of all three species. In contrast under a fluctuating water regime, nutrient addition did not influence total biomass of either T. domingensis or T. procerum and the performance of C. gymnocaulos was reduced by ca. 30%. These data suggest that if environmental flows were managed to provide a natural stochastically fluctuating water regime, this would nullify the influence of nutrient enrichment and limit the distribution and spread of invasive species such as Typha, that exists under the current altered conditions. Copyright © 2010 John Wiley & Sons, Ltd.     

Cardiac transplantation in perspective for the future. Survival, complications, rehabilitation, and cost

Two hundred twenty-seven cardiac transplant procedures have been performed in 206 patients from January, 1968, to April, 1981. Postoperative survival rates, calculated by the actuarial method for program years 1968 to 1973 (66 patients), are 44%, 33%, 27%, 21%, and 18% at 1, 2, 3, 4, and 5 years after transplantation, respectively. Postoperative survival rates for program years 1974 to 1981 (140 patients) are 63%, 55%, 51, 44%, and 39% at 1, 2, 3, 4, and 5 years after transplantation, respectively. This increase results primarily from improvement in survival achieved in the first 3 postoperative months (59% +/- 7%, 1968 to 1973, versus 80% +/- 40%, 1974 to 1980), reflecting improved patient management. Infection remains the primary cause of death following transplantation (76/131 patients, 58%), followed by acute rejection (24/181, 18.3%), graft arteriosclerosis (14/131, 10.7%), and malignancy (6/131, 4.6%). The development of graft arteriosclerosis has been examined in 85 one-year survivors studied by annual coronary arteriograms. Coronary lesions of varying severity have developed in 21 patients. HLA-A2 incompatibility was associated with a higher incidence of graft arteriosclerosis than was apparent for all other A locus incompatibilities (p less than 0.0003). Lymphoma has been shown to be associated with younger recipient age, a primary disease diagnosis of idiopathic cardiomyopathy, and retransplantation. One hundred six patients have survived at least 1 year after transplantation; 97% were in NYHA Class 1 at that time interval and 82% returned to employment or activity of choice. The longest survival time is new 11 years, 3 months. Cardiac transplantation can be considered "reasonable and therapeutic treatment to extend life" in selected individuals.     

Fabrication-tolerant active-passive integration scheme for vertically coupled microring resonator

The large-scale photonic integration of microring resonators in three dimensions made possible by recent developments in vertical coupling and wafer bonding technology is shown to be sensitive to lateral mask misalignment for the ring and bus waveguides introduced during the fabrication process. For a typical 20-/spl mu/m radius, vertically coupled microring calculations reveal a linear relationship between deviation in the coupling coefficient and lateral misalignment. A coupling coefficient reduction of 50% is predicted for a lateral misalignment of 0.3 /spl mu/m, which is typical for an alignment accuracy limited by the current state-of-the-art mask alignment process. The use of a wide multimode bus waveguide is proposed to ameliorate this alignment sensitivity. The mode-expanded bus waveguide, together with its physically wider structure, reduces the dependence of modal overlap and coupling length on precise alignment, resulting in significantly relaxed fabrication tolerance. Deviation of coupling coefficient decreases by an order of magnitude for the new ring coupler geometry, where a sole reduction of 5% is obtained for the same amount of misalignment. The implications of the proposed structure are subsequently investigated for microring laser performance. The differential slope efficiency is shown to be at least five times less sensitive to lateral misalignment for the proposed structure within a small misalignment regime. This readily adaptable coupler geometry based on existing vertical coupling architectures is transferable to any fabrication scheme with multiple waveguide layers coupled vertically, and is of particular importance to microring resonators with small radii.     

An X-ray beam position monitor based on the photoluminescence of helium gas

A new method for white beam position monitoring for both bend magnet and wiggler synchrotron X-ray radiation has been developed. This method utilizes visible light luminescence generated as a result of ionization by the intense X-ray flux. In video beam position monitors (VBPMs), the luminescence of helium gas at atmospheric pressure is observed through a view port using a CCD camera next to the beam line. The beam position, profile, integrated intensity and FWHM are calculated from the distribution of luminescence intensity in each captured image by custom software. Misalignment of upstream apertures changes the image profile making VBPMs helpful for initial alignment of upstream beam line components. VBPMs can thus provide more information about the X-ray beam than most beam position monitors (BPMs). A beam position calibration procedure, employing a tilted plane-parallel glass plate placed in front of the camera lens, has also been developed. The accuracy of the VBPM system was measured during a bench-top experiment to be better than 1 μm. The He-luminescence-based VBPM system has been operative on three CHESS beam lines (F hard-bend and wiggler, A-line wiggler and G-line wiggler) for about a year. The beam positions are converted to analog voltages and used as feedback signals for beam stabilization. In our paper we discuss details of VBPM construction and describe further results of its performance.     

An evaluation of the development of IT in a college of nursing and midwifery

This paper presents the findings of a case study of the development of IT in a College of Nursing and Midwifery. Data were collected by means of postal questionnaires, interviews, focus groups, direct observations and documentary evidence. The findings suggest that the majority of staff used some form of IT on a regular basis, but only 50% of students used college-based IT facilities. The main use of IT was for administrative and productive purposes and there was little evidence of IT in teaching/learning methods. Training offered to staff was poorly attended and training offered to students did not meet what they perceived as their needs. Although most staff used IT there was still evidence of resistance and stress related to IT use. The use of IT in the study college was driven by tactical considerations rather than as a part of an explicit strategy.     

Piezoelectric paint: Ceramic-polymer composites for vibration sensors

A piezoelectric ceramic-polymer composite has been developed for use as a novel thick film strain sensor for vibration monitoring of structures. The material is in the form of a paint that can be applied to a wide range of substrates using conventional spraying equipment. The sensor properties depend on the morphology of the composite and on the electrodes that are used to couple it to the charge amplifier. Electrodes of various kinds have been tested. Interaction between the electrode and the piezoelectric paint sometimes occurs (for example, the organic vehicle for spray-coated electrodes may interact with the paint binder). The morphologies of the piezoelectric paint and of the electrode materials have been studied using light optical microscopy and scanning electron microscopy to investigate the effect of different compositions and of different processing conditions (e.g., paint mixing schedule). Preliminary work is reported on the characteristics of the piezoelectric particles and on the effect of heat treatment applied to anneal out defects produced by milling. X-ray analysis and particle size analysis have been used to characterize the changes that take place on heat treatment. X-ray diffractometry has also been used to follow the effect of poling on the paint sensors. At the present state of development, sensors made using the paint have a dynamic range of at least 40–4000 microstrain and a bandwidth of at least 1 Hz–2 kHz, and piezoelectric coefficient d ₃₁ of approximately 20 pC/N. The sensors are resistant to outdoor exposure and a successful field trial has been conducted.     

Reward,persuasion, and the Sokal Hoax: A study in citation identities

A citation identity is a list of an author's citees ranked by how frequently that author has cited them in publications covered by the Institute for Scientific Information. The same Dialog software that creates identities can simultaneously show the overall citation counts of citees, which indicate their reputations. Using identities for 28 authors in several disciplines of science and scholarship, I show that the reputational counts of their citees always have an approximately log-normal distribution: citations to very famous names are roughly balanced by citations to obscure ones, and most citations go to authors of middling reputation. These results undercut claims by constructivists that the main function of citation is to marshal “big-name” support for arguments at the expense of crediting lesser-known figures. The results are better explained by Robert K. Merton's norm of universalism, which holds that citers are rewarding use of relevant intellectual property, than by the constructivists' particularism, which holds that citers are trying to persuade through manipulative rhetoric. A universalistic citation pattern appears even in Alan Sokal's famous hoax article, where some of his citing was deliberately particularistic. In fact, Sokal's basic adherence to universalism probably helped his hoax succeed, which suggests the strength of the Mertonian norm. In specimen cases, the constructivists themselves are shown as conforming to it. This revised version was published online in June 2006 with corrections to the Cover Date.     

Amygdala Inactivation Blocks Expression of Conditioned Memory Modulation and the Promotion of Avoidance and Freezing.

Rats were exposed to shock-paired cues immediately after training on an appetitive preference task. Elevated levels of freezing in and active avoidance of the shock-paired compartment were observed, and memory for the appetitive task was improved when tested 24 hr later. Intra-amygdala muscimol injected before the posttraining exposure eliminated freezing, avoidance, and memory modulation. The blockade of both freezing and active avoidance, which involve competing behavioral tendencies, makes it unlikely that the amygdala itself generates either behavior. The elimination of conditioned memory modulation suggests that conditioned neurohormonal responses were blocked. These conditioned internal responses may comprise the intervening variable of "conditioned fear" and may promote observable behaviors, the form of which is determined by the environment in which they occur. (PsycINFO Database Record (c) 2010 APA, all rights reserved)