Seasonal patterns of protoplankton and calanoid copepods in the Firth of Forth : an investigation or Copepod grazing and the effect of diatoms upon reproductive processes

Seasonal variability in the zooplankton of the Firth of Forth, including mesozooplankton and microplankton, were investigated across a full annual cycle. Grazing rates and prey selectivity by the dominant calanoid copepods (Acartia discaudata, Acartia clausi, Centropages hamatus and Temora longicornis) were also examined. Investigations were conducted upon Acartia discaudata and field collected prey under simulated diatom bloom conditions, using the species Thalassiosira rotula, in order to test the hypothesis of diatom inhibition of calanoid copepod reproductive processes. There were fundamental differences between the spring and autumn blooms, typical of temperate estuaries. The spring bloom was composed of highly abundant, small cells amounting to less than half the biomass of larger, less numerous microplankton present in autumn. Copepods dominated the mesozooplankton undergoing seasonal shifts in species’ dominance primarily in response to physical factors. Results of grazing experiments indicate a disproportionate preference for motile prey compared to ubiquitous concentrations of diatoms. Copepods switch to blooming diatom species when present in concentrations > 80 cells ml-1. Ciliates generally contributed < 25% to copepod carbon ingestion. Acartia discaudata, Acartia clausi, and Centropages hamatus selectively consumed dinoflagellate and ciliate taxa whereas Temora longicornis remained an indiscriminate grazer during the entire study. Despite increasing rates of egg production in Acartia discaudata, at high concentrations (> 1 x 103 cells ml-1), Thalassiosira rotula inhibited hatching success such that recruitment to naupliar stage 2 was severely impaired compared with eggs hatched from females fed ~0.3 x 103 cells ml-1 concentrations of T. rotula. This is the first recorded evidence of embryogenic inhibition in A. discaudata

The Maximum Number of Appearances of a Word in a Grid

How can you fill a $3\times 3$ grid with the letters A and M so that the word ``AMM'' appears as many times as possible in the grid? More generally, given a word $w$ of length $n$, how can you fill an $n\times n$ grid so that $w$ appears as many times as possible? We solve this problem exactly for several families of words, and we asymptotically solve this problem in higher-dimensional grids.Comment: 21 pages, American Mathematically Monthl

Ultra-narrow (sub-MHz) linewidth emission from discrete mode laser diodes

A class of laser which exhibits ultra-narrow sub MHz linewidth emission necessary for numerous applications in optical communications and sensors is described. The spectral performance of commercial discrete mode (DM) and distributed feedback (DFB) lasers is compared. The devices used in this work are asymmetrically coated ridge waveguide Fabry Perot lasers which incorporated etched slot features and emitting around lambda = 1.55 mum. The active region of the devices consisted of a strained compensated InAlGaAs MQW structure

Low sensitivity to optical feedback and optical injection of discrete mode lasers

In this paper, we demonstrate the low sensitivity to both external optical feedback and external optical injection of a new type of extremely low cost single-mode lasers, called "discrete mode" (DM) lasers. The DM lasers are obtained from ridge waveguide Fabry Perot (FP) lasers, in which the effective refractive index of the lasing mode has been perturbed. These lasers exhibit a low sensitivity to external optical feedback since the coherence collapse threshold is around 5 dB higher in comparison to a commercial DFB laser

Self-pulsation at 480 GHz from a two-color discrete mode laser diode

A discrete mode Fabry-Pérot laser is designed and fabricated to achieve two-color lasing. We demonstrate beating between the two laser modes and self-pulsation at 480 GHz

Inverse scattering approach to multiwavelength Fabry-Pérot laser design

A class of multiwavelength Fabry-Pérot lasers is introduced where the spectrum is tailored through a patterning of the cavity effective index. The cavity geometry is obtained using an inverse scattering approach and can be designed such that the spacing of discrete Fabry-Pérot lasing modes is limited only by the bandwidth of the inverted gain medium. A specific two-color semiconductor laser with a mode spacing in the THz region is designed, and measurements are presented demonstrating the simultaneous oscillation of the two wavelengths. The nonperiodic effective index profile of the particular two-color device considered is shown to be related to a Moiré or superstructure grating

An assessment of key risk factors for surgical site infection in patients undergoing surgery for spinal metastases

Objectives This study aimed to determine the rate of surgical site infection (SSI) in patients undergoing surgery for spinal metastases, and identify key risk factors for SSI among this patient group. Methods A retrospective case note review was undertaken in 152 adult patients being treated at a single specialist centre for spinal surgery. Results Overall SSI rate was 11.2% per patients (9.7% per procedure). An increase in the risk of SSI was observed when surgery involved a greater number of vertebral levels (odds ratio 1.26, P=0.019) when controlling for primary spinal region. Controlling for the number of spinal levels, the odds of SSI increased by a factor of 5.6 (P=0.103) when the primary surgical region was thoracic, as opposed to cervical or lumbar. Conclusions In conclusion, surgery associated with multiple vertebral levels for treatment of spinal metastases, particularly of the thoracic spine, is associated with increased risk of SSI

Studies on the biology of the Catfish: Ictalurus Nebulosus Le Sueur in the Waikato Region

This study investigated the age and growth, reproductive and feeding biology of the North American catfish Ictalurus nebulosus Le Sueur in the Waikato Valley of New Zealand, the changes that have occurred during acclimatisation and the extent of the differences in biology between here and other regions of the world. Under Waikato conditions the growth rate of the catfish was much faster than is usual for the species, although the longevity of about 8 years was the same as in the northern hemisphere. Oocyte development in the ovaries was asynchronous (Marza, 1938), with multiple spawning occurring. The duration of the spawning season was nine months, from winter to early autumn. Fecundity estimates were of a minimum of 3700 eggs laid per season. The major foods of the catfish were chironomid larvae, oligochaete worms, molluscs and crustacea. There was no evidence of piscivorous or fish-egg eating habits as has been noted for the species overseas. The catfish is expanding in numbers and range throughout the Waikato region because the recruitment capabilities of the population are high, with a rapid growth rate and high, fecundity, and there is an apparent lack of natural predators

Primary Carcinoid Tumor of the Skull Base: Case Report and Review of the Literature

We present an unusual case of primary intracranial carcinoid tumor of the skull base centered at the level of the foramen jugulare, which was proven with surgical biopsy and later with Somatostatin receptor nuclear medicine scan. We present the salient magnetic resonance imaging features of this rare tumor, describe their characteristic nuclear medicine findings, and briefly review the literature.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79329/1/j.1552-6569.2008.00317.x.pd