Kin composition effects on reproductive competition among queenless honeybee workers

Kin selection and inclusive fitness theories predict that, in hopeless queenless (QL) groups, competition or cooperation will occur over male production among workers of different patrilines. Competition is expected to involve mutual inhibition of reproduction and to affect fertility advertisement. To examine kin effect on these phenomena, we studied QL groups of honeybee workers comprising three types of kin structure: groups composed of pure single patrilines, groups composed of three mixed patrilines (all originating from colonies headed by single-drone-inseminated queens), and control groups composed of bees originating from naturally mated queens. Global assessment of ovarian development, irrespective of patriline composition, revealed no differences among group types. In contrast, the performance of specific patrilines revealed that, in the three-mixed-patriline groups, some patrilines were reproductively suppressed compared to their performance when reared as a pure single patriline, resulting in an uneven share of reproduction. Analysis of the fertility signal produced by Dufour's gland revealed kin composition effects, which may reflect the bees' competitive efforts. Although patriline effects on worker reproductive superiority have been shown in QL colonies, we were able to investigate specific patriline performance both in competitive and noncompetitive situations here for the first time. The results are consistent with the hypothesis that reproductive and pheromonal competitions in QL groups are affected by the number of subfamilies populating a colony and that these act as coalitions. The results also emphasize that within-colony heterogeneity, in the form of multiple patrilines, has far-reaching consequences on social evolution.     

Mineralogical and chemical characterization of suspended atmospheric particles over the east Mediterranean based on synoptic-scale circulation patterns

Suspended atmospheric particles were collected in Israel in order to identify their nature and relationships with the major synoptic-scale circulation patterns. The particles were analyzed for their major and trace element concentrations and mineralogical composition. Samples were collected during three synoptic systems associated with desert dust storms: Red Sea trough, Sharav cyclone and cold depression, and during deep and shallow modes of Persian Gulf trough, which prevails in the summer months and is not associated with dust storms.All samples mostly contain particles smaller than 2 μm. The suspended desert dust is composed primarily of illite–smectite and calcite. Some indicative secondary minerals were found for each of the dust transporting synoptic systems (e.g., palygorskite for Red Sea trough). The bulk chemistry data support the mineralogical observations and reveal additional chemical signatures of each dust transporting system. For instance, Red Sea trough samples have significantly higher Ca/Al and Ca/Mg in the carbonate and Mg/Al in Al-silicate fraction than cold depression samples. Nevertheless, Sharav cyclone samples have intermediate values in spite of the fact that the source of the dust during these conditions is similar to cold depression (i.e., North Africa). Even though differences in the chemical and the mineralogical composition of desert dust do exist, this study reveals their overall chemical and mineralogical similarities.In contrast to the synoptic systems that carry desert dust, the inorganic fraction of the Persian Gulf trough samples contains significant amount (up to 50%) of non-mineral material that has a pronounced chemical signature in terms of major element concentrations (e.g., Al, Ca, Mg, Na, S) implying their anthropogenic nature, probably from countries around the Black Sea. This striking finding is indicative for atmospheric pollution in the Eastern Mediterranean region during the summer.     

Prenatal diagnosis of cystic fibrosis: Ultrasonographic appearance of meconium ileus in the fetus

Four often fetuses carrying a risk of 1:4 for cystic fibrosis were found to have low levels of microvillar enzymes in the amniotic fluid obtained between 17 and 18 weeks' gestational age. On sonography performed prior to the amniocentesis, three fetuses showed enlarged bowel loops. At autopsy, meconium ileus was detected. Enlarged bowel loops are a sign which has not been described previously so early in pregnancies.     

The “Short Cut” Approach for the Reality of Enhanced Groundwater Contamination

Based on the reality of (a) soil heterogeneity in the vadose zone, (b) enhanced desorption from soil and solubility in water of water insoluble contaminants in the presence of surfactants, and (c) wetting/drying cycles of groundwater recharge (a major cause of fractures formation), a coherent “short-cut” conceptual approach is advanced to account for enhanced groundwater contamination. This is an attempt to close the gap between theory, lab simulations and conventional modelling-based predictions, and observed higher concentrations and more rapid arrival times of contaminants reaching groundwater. Recent data concerning chloride ion and non-ionic surfactants concentrations in aquifers and groundwater wells, combined with previous results concerning the concentrations of tritium, chlorides, metals, organic hydrocarbons and surfactants in the unsaturated and saturated zones of Israel's aquifers, are accounted for in terms of the “short-cut” approach. The contradiction between predictions of groundwater contamination made with conventional, deterministic, homogeneous models and the actual observed behavior of contaminants in soils and aquifers is thus explaind. The “short cut” approach should not be perceived as a better type of model to guide modelling. Rather, it is a proposal for a conceptual change from the realistically invalid, but commonly accepted, conventional “buffer-protective soil/long-term groundwater contamination” to the “short cut” conceptual model to explain the enhanced groundwater contamination actually observed. Although the validity of the proposed approach is strongly supported by the data here presented for the case of Israel (serving as an illustrative case study), selected results and conclusions drawn from studies conducted worldwide suggest its general applicability and usefulness. A major conclusion evolved from the “short-cut” conceptual model is that contemporary groundwater management policies, based on the current perception of groundwater contamination processes and their modelling, may result in an irreversible detrimental effect on the environmental situation in the long run. In any case, prevention, rather than correction/remediation, is strongly recommended as the strategy of choice for rational long-term management of groundwater resources.     

Practical and mechanistic aspects of the removal of cadmium from aqueous systems using peat

A sphagnum peat moss removed Cd from aqueous solutions very efficiently, and its effectiveness in taking up the metal was significantly enhanced by exposure to a 1N NaOH solution. The capacity of the untreated peat for Cd reached 300 g/kg and that of the NaOH-activated peat was over 400 g/kg. Although saturation was rarely reached, the Cd uptake from concentrated solutions often exceeded 200 g/kg. In column experiments, 1g of the NaOH-activated peat completely removed the metal from over 0.2L of a 200-mg/L Cd solution (final Cd concentration<0.1mg/L), while 1g of non-activated peat cleared Cd from less than 25% of that volume. The cation exchange capacity measured for the peat depended on the time of contact with the exchanging solution. After 72 h contact, the value for the NaOH-activated peat was 135 cmol(c)/kg. In addition to uptake by exchange, a significant amount of Cd was sorbed by non-exchange mechanisms. FTIR spectroscopy revealed the importance of carboxyl groups in the uptake.     

Simple digestion procedure followed by the azomethine-H method for accurate boron analysis and discrimination between its fractions in wastewater and soils

Excess boron is a growing environmental problem. It often affects agricultural yields, where reuse of wastewater for irrigation is practiced. This problem raises the need for reliable, simple and economical methods to monitor boron concentrations in wastewater and soil extracts. One such method, the commonly used azomethine-H spectrophotometric method, suffers from color interference, originating from high concentrations of dissolved organic matter, when applied to many wastewater and agricultural soil extracts. Moreover, this method only quantifies free dissolved boron and lacks the ability to quantify boron that is adsorbed to either the dissolved organic matter or suspended solids that are present in the sample. This work suggests a modification of the standard azomethine-H method, in which the solution is digested with potassium persulfate prior to the standard procedure. We show that this pretreatment can overcome the color interference and lead to highly accurate and precise boron analyses in wastewater. In soil extracts, the boron concentrations obtained using the suggested procedure were better correlated to inductively coupled plasma (ICP) spectrometry results than those measured by the standard method, because whereas the standard method quantifies the free dissolved boron only, the modified method, like the ICP method, quantifies the total dissolved boron in the sample. Thus, the suggested modification can be used to quantify the respective distributions of free dissolved boron, boron adsorbed to dissolved organic matter and boron adsorbed to suspended solids in soil extracts and water samples.     

On the optimal allocation of pesticides with increasing resistance: The case of alfalfa weevil

The problem of pesticide application under increasing pesticide resistance is explored. A theoretical model is developed to determine optimal pesticide use. This allocation is compared to the laissez-faire solution and to the centralized solution with incomplete information about pesticide resistance. The methodology is then applied in a case study on the Egyptian alfalfa weevil in California.