Clustering of halophytic species from Cyprus based on ionic contents

This paper presents the work conducted on the chemical constituents of some common and widely distributed halophyte taxa from Cyprus with the aim that these studies will help in the evaluation of halophytes for different economical purposes. The plant species of Crithmum maritimum L., Limbarda crithmoides (L.) Dumort, Atriplex portulacoides L., Salsola kali L., Atriplex halimus L., Limonium oleifolium Mill., L. meyeri (Boiss.) Kuntze; and Tetraena alba (L.f.) Beier & Thulin were collected in the middle of July. The shoot tissue and leaf samples were collected from the natural habitats and left for drying under air circulation followed by placing them in oven at 60 °C for 96 hours. The material was crushed using mortar and pestle and subjected to an analysis of macro- and micro-nutrients and biochemical compounds. K⁺/Na⁺ in the leaf tissues of the dicot species showed relatively high values depicting their behavior as Na+ includes but very low Cl- levels were recorded. Out of the species investigated here in 4 TFAA content was rather high. Values ranging from 0.5% to 1% dry weight were exhibited in one species. However, only 3 species showed very low TFAA values. Later may be due to low nitrogen availability in their environment. The phenetic analyses of eight halophyte species performed on the data matrix using Ntsys-pc program version 2.1 revealed that, cluster analysis of the overall results obtained here leads to 2 clusters. This discrimination appears to be as a result of their different abilities to accumulate either proline or glycine betaine.     

A continuous lactic acid production system using an immobilized packed bed of Lactobacillus helveticus

A 5 l packed bed bioreactor was used to study the effect of initial lactose concentration and hydraulic retention time (HRT) on cell growth, lactose utilization and lactic acid production. Up to 95% of the initial lactose concentration was utilized at longer HRTs (30-36 h). The study showed that lactic acid production increased with increases in HRT (12-36 h) and initial lactose concentrations. The highest lactic acid production rate (3.90 g l(-1) h(-1)) was obtained with an initial lactose concentration of 100 g/l and an HRT of 18 h, whereas the lowest lactic acid production rate (1.35 g l(-1) h(-1)) was obtained with an initial lactose concentration of 50 g/l and an HRT of 36 h. This suggested that optimal lactic acid production can be achieved at an HRT of 18 h and initial lactose concentration of 100 g/l.     

Impacts and potential effects due to Prorocentrum minimum blooms in Chesapeake Bay

The dinoflagellate Prorocentrum minimum (P. minimum) can be found in all seasons and over a broad range of habitat conditions in the Chesapeake Bay and its tributaries. Blooms (>3000 cells ml⁻¹), locally referred to as ‘mahagony tides’, were restricted to salinities of 4.5–12.8 psu, water temperatures of 12–28 °C, and occurred most frequently in April and May. P. minimum blooms have been detected at routine water quality monitoring stations located in the main channel of the Bay and tidal tributaries. Nearshore investigations of bloom events, however, have accounted for the majority of events recorded in excess of 10⁵ cells ml⁻¹. Mahogany tides were associated with widespread harmful impacts including anoxic/hypoxic events, finfish kills, aquaculture shellfish kills and submerged aquatic vegetation losses. We summarize the state of knowledge regarding physical and chemical factors related to P. minimum blooms, their abundance, distribution and frequency, and ecological effects in Chesapeake Bay.     

A comparative study of alteration in lymphocyte subsets among varicella, hand-foot-and-mouth disease, scarlet fever, measles, and Kawasaki disease

Changes in the lymphocyte subsets of 13 patients with varicella, 5 with hand-foot-and-mouth disease, 4 with scarlet fever, 10 with measles and 20 with Kawasaki disease were examined by immunofluorescent flow cytometric analysis using monoclonal antibodies against lymphocyte cell surface antigens. The results were compared with those of age-matched normal controls. A significant increase in the percentage of Leu-2a positive (Leu-2a+) cells was shown during the early convalescence of varicella, scarlet fever and measles. A significant decrease in the percentage of Leu-3a+ cells during the acute phase was common to all the diseases examined, and a significant decrease of Leu-4+ cells was observed except in measles. As a result, a significant decrease in the Leu-3a+/Leu-2a+ ratio was common to all the diseases examined during the acute and/or early convalescent phases. Leu-M3+ cells increased significantly in varicella, scarlet fever, and Kawasaki disease. HLA-DR+ cells increased significantly in varicella and Kawasaki disease. No significant changes in the proportions of Leu-7+, Leu-10+, and 2H7+ cells were found throughout the course of all the diseases examined.     

Altered immune responsiveness in patients with chronic glomerulonephritis

In order to detect abnormalities in humoral immunity and to determine immunogenetic traits underlying chronic glomerulonephritis, sera from 260 patients who had chronic glomerulonephritis and who were undergoing hemodialysis were tested for naturally occurring antibodies against mycoplasma and 22 different viruses. Among the 23 microorganisms tested, antibody titers were significantly lower against 12, higher against 3, and no different against 8 when compared with titers of 43 normal subjects. The data were analyzed further by plotting each in a 23-dimensional space according to their standardized antibody titers. Multivariate cluster analysis by the Ward's method revealed 3 large clusters differing from each other in natural antibody titers, and one of the clusters included 74% of the normal controls, while two other distinct clusters comprised the majority of the patients. The level of BUN, creatinine, and duration of hemodialysis treatment did not differ significantly among patients in these three different clusters. Our study suggests that patients with chronic glomerulonephritis being treated by hemodialysis have altered levels of naturally occurring antibodies to microorganisms. This alteration is not caused by just the uremic state or hemodialysis but immunogenetic regulation may also play a part.     

Asymptotic distribution of an index for disease clustering

Tango (1984, Biometrics 40, 15-26) proposed an index for disease clustering in time, applicable to grouped data with the assumption that the population at risk remains fairly uniform over the study period. However, the asymptotic distribution of the index derived under the hypothesis of no clustering was rather complex for simple use. Recently, Whittemore and Keller (1986, Biometrics 42, 218) and Whittemore et al. (1987, Biometrika 74, 631-635) proved that the distribution of the index is asymptotically normal. The present paper indicates that their approximation may be poor for moderately large sample sizes and suggests a central chi-square distribution as a better approximation to the asymptotic distribution of this index.     

A class of multiplicity adjusted tests for spatial clustering based on case-control point data

A class of tests with quadratic forms for detecting spatial clustering of health events based on case-control point data is proposed. It includes Cuzick and Edwards's test statistic (1990, Journal of the Royal Statistical Society, Series B 52, 73-104). Although they used the property of asymptotic normality of the test statistic, we show that such an approximation is generally poor for moderately large sample sizes. Instead, we suggest a central chi-square distribution as a better approximation to the asymptotic distribution of the test statistic. Furthermore, not only to estimate the optimal value of the unknown parameter on the scale of cluster but also to adjust for multiple testing due to repeating the procedure by changing the parameter value, we propose the minimum of the profile p-value of the test statistic for the parameter as an integrated test statistic. We also provide a statistic to estimate the areas or cases which make large contributions to significant clustering. The proposed methods are illustrated with a data set concerning the locations of cases of childhood leukemia and lymphoma and another on early medieval grave site locations consisting of affected and nonaffected grave sites.