Heavy metals pollution in the coastal environment of Karachi

The marine environment near Karachi, particularly the Baba channel, Chari Kundi channel and Manora channel have been found contaminated with industrial effluents discharged by Malir and Lyari rivers, since they carry a high concentration of toxic heavy metals viz. Pb, Zn, Cu and Mn emanating from the industrial area and are received and discharged by the Lyari river. Out of 60 seawater samples collected from the above mentioned areas, Pb was present in 55 samples and Zn in 58 samples. The concentration of Pb was between 0.04 and 59.2ppm and the concentration of Zn was between 0.05 and 1.9ppm. Similarly all the 60 sludge samples collected from Lyari outfall and its adjoining area have been found to contain Pb and Zn in alarmingly high concentratios, which for Pb was between 15.4 and 3209.9ppm while for Zn was between 87 and 111.3ppm. Cu and Mn were also found in all the above samples.

Ecological imbalances in the coastal areas of Pakistan and Karachi Harbour

The marine environment of Pakistan has been described in the context of three main regions : the Indus delta and its creek system, the Karachi coastal region, and the Balochistan coast. The creeks, contrary to concerns, do receive adequate discharges of freshwater. On site observations indicate that freshwater continues flowing into them during the lean water periods and dilutes the seawater there. A major factor for the loss of mangrove forests as well as ecological disturbances in the Indus delta is loss of the silt load resulting in erosion of its mudflats. The ecological disturbance has been aggravated by allowing camels to browse the mangroves. The tree branches and trunks, having been denuded of leaves are felled for firewood. Evidence is presented to show that while indiscriminate removal of its mangrove trees is responsible for the loss of large tracts of mangrove forests, overharvesting of fisheries resources has depleted the river of some valuable fishes that were available from the delta area. Municipal and industrial effluents discharged into the Lyari and Malir rivers and responsible for land-based pollution at the Karachi coast and the harbour. The following are the three major areas receiving land-based pollution and whose environmental conditions have been examined in detail: (l) the Manora channel, located on the estuary of the Lyari river and serving as the main harbour, has vast areas forming its western and eastern backwaters characterized by mud flats and mangroves. The discharge of industrial wastewater from the S.I.T.E. and municipal effluents from the northern and central districts into the Lyari has turned this river into an open drain. This, in turn, has caused a negative impact on the environment of the port, fish harbour, and the adjacent beaches. (2) The Gizri creek receives industrial and municipal effluents from the Malir river as well as from several industries and power stations. The highly degraded discharges from the Malir have negatively impacted the environment in this creek. (3) The coastline between the Manora channel and Gizri creek where the untreated municipal effluents are discharged by the southern districts of Karachi, is responsible for the degraded environment of the Chinna creek, and also of the beaches and the harbour. The Balochistan coast is relatively safe from land-based pollution, mainly because of the lack of industrial, urban or agricultural activity, except the Hingol river system where some agricultural activities have been initiated.

DRAMATIC CONSEQUENCES OF FOOD HANDOUTS TO MACACA-THIBETANA AT MOUNT-EMEI, CHINA

Food handouts to Macaca thibetana at Mt. Emei have had dramatic consequences for both man and monkey as tourism has increased over the last decade. Food handouts and human submissive behaviour facilitate beg-robbing by the monkeys. which can be regarded as a mixed conditioning chain. Because of their lack of understanding of primate behaviour and resulting inappropriate responses, many visitors have lost possessions and have been severely frightened or even injured; in fact there have been 1 0 deaths as an indirect result over that past 8 years. The appropriate human response proved to be the display of dominance to maintain a distance from a beg-robbing monkey. Road-ranging macaques have also been injured or killed by visitors to obtain meat or bones or merely for amusement. Attempts should be made to eliminate the negative effects of food handouts by increasing visitors' awareness of behavioural and ecological aspects and through aversive conditioning of the macaques.

The double bind for non-traditional families in post-primary settings; to tell or not to tell their family identity

This thesis involved researching normative family discourses which are mediated through educational settings. The traditional family, consisting of father, mother and children all living together in one house is no longer reflective of the home situation of many Irish students (Lunn and Fahey, 2011). My study problematizes the dominant discourses which reflect how family differences are managed and recognised in schools. A framework using Foucauldian post structural critical analysis traces family stratification through the organisation of institutional and interpersonal relations at micro level in four post-primary schools. Standardising procedures such as the suppression of intimate relations between and among teacher and student, as well as the linear ordering of intergenerational relations, such as teacher/student and adult/child are critiqued. Normalising discourses operate in practices such as notes home which presume two parents together. Teacher assumptions about heterosexual two-parent families make it difficult for students to be open about a family setup that is constructed as different to the rest of the schools'. The management of family difference and deficit through pastoral care structures suggests a school-based politics of family adjustment. These practices beg the question whether families are better off not telling the school about their family identity. My thesis will be of interest to educational research and educational policy because it highlights how changing demographics such as family compositions are mis-conceptualised in schools, as well as revealing the changing forms of family governance through regimes such as pastoral care. This analysis allows for the existence of, and a valuing for, alternative modes of family existence, so that future curricular and legal discourses can be challenged in the interest of equity and social justice.

Decoding an olfactory mechanism of kin recognition and inbreeding avoidance in a primate.

BACKGROUND: Like other vertebrates, primates recognize their relatives, primarily to minimize inbreeding, but also to facilitate nepotism. Although associative, social learning is typically credited for discrimination of familiar kin, discrimination of unfamiliar kin remains unexplained. As sex-biased dispersal in long-lived species cannot consistently prevent encounters between unfamiliar kin, inbreeding remains a threat and mechanisms to avoid it beg explanation. Using a molecular approach that combined analyses of biochemical and microsatellite markers in 17 female and 19 male ring-tailed lemurs (Lemur catta), we describe odor-gene covariance to establish the feasibility of olfactory-mediated kin recognition. RESULTS: Despite derivation from different genital glands, labial and scrotal secretions shared about 170 of their respective 338 and 203 semiochemicals. In addition, these semiochemicals encoded information about genetic relatedness within and between the sexes. Although the sexes showed opposite seasonal patterns in signal complexity, the odor profiles of related individuals (whether same-sex or mixed-sex dyads) converged most strongly in the competitive breeding season. Thus, a strong, mutual olfactory signal of genetic relatedness appeared specifically when such information would be crucial for preventing inbreeding. That weaker signals of genetic relatedness might exist year round could provide a mechanism to explain nepotism between unfamiliar kin. CONCLUSION: We suggest that signal convergence between the sexes may reflect strong selective pressures on kin recognition, whereas signal convergence within the sexes may arise as its by-product or function independently to prevent competition between unfamiliar relatives. The link between an individual's genome and its olfactory signals could be mediated by biosynthetic pathways producing polymorphic semiochemicals or by carrier proteins modifying the individual bouquet of olfactory cues. In conclusion, we unveil a possible olfactory mechanism of kin recognition that has specific relevance to understanding inbreeding avoidance and nepotistic behavior observed in free-ranging primates, and broader relevance to understanding the mechanisms of vertebrate olfactory communication.

Laser technology - Measuring huge magnetic fields

Huge magnetic fields are predicted1–4 to exist in the high-density region of plasmas produced during intense laser–matter interaction, near the criticaldensity surface where most laser absorption occurs, but until now these fields have never been measured. By using pulses focused to extreme intensities to investigate laser–plasma interactions5, we have been able to record the highest magnetic fields ever produced in a laboratory – over 340 megagauss – by polarimetry measurements of self-generated laser harmonics.

Proton acceleration from high-intensity laser interactions with thin foil targets

Measurements of energetic proton production resulting from the interaction of high-intensity laser pulses with foil targets are described. Through the use of layered foil targets and heating of the target material we are able to distinguish three distinct populations of protons. One high energy population is associated with a proton source near the front surface of the target and is observed to be emitted with a characteristic ring structure. A source of typically lower energy, lower divergence protons originates from the rear surface of the target. Finally, a qualitatively separate source of even lower energy protons and ions is observed with a large divergence. Acceleration mechanisms for these separate sources are discussed.

Coexistence among native and introduced freshwater amphipods (Crustacea); habitat utilization patterns in littoral habitats

Studies of biological invasions predominantly stress threats to biodiversity through the elimination and replacement of native species. However, we must realise that resident communities may often be capable of integrating invaders, leading to patterns of coexistence. Within the past ninety years, three freshwater amphipod species have invaded Northern Ireland the North American Gammarus tigrinus and Crangonyx pseudogracilis, plus the European G. pulex. These species have come into contact with the ubiquitous native species, G. duebeni celticus. This study examined spatiotemporal patterns of stability of single and mixed species assemblages in an invaded lake. Lough Beg and its associated rivers were surveyed in summer 1994 and winter 1995, and a selection of stations re-sampled in summer one and five years later. All possible combinations of the four amphipod species were found. Although species presence/absence was stable between seasons at the scale of the whole lough, it was extremely fluid at the scale of individual sites, 82% of which changed in species composition between seasons. Overall mean amphipod abundance was similar across 5 distinguishable habitat types, but there were differences in species compositions among these habitats. In addition, although co-occurrences of Gammarus species did not differ from random, there was a strong negative association between Gammarus spp. and C. pseudogracilis. This latter pattern was at least in part generated by the better tolerance of C. pseudogracilis to lower water quality. A review of previous studies indicates that the exclusion of C. pseudogracilis by Gammarus species from high water quality areas is likely to involve biotic interaction. Thus, overall, co-existence of the four species, which is clearly dynamic and scale-dependent, appears promoted by spatial and temporal habitat heterogeneity. However, biotic interactions may also play a role in local exclusions. Since the three introduced species have not eliminated the native species, and each successive invasion has not replaced the previous invader, this study demonstrates that freshwater invaders may integrate with native communities leading to coexistence and increased species diversity.

Signals of need in a cooperatively breeding mammal with mobile offspring

In many bird species with biparental care for young in the nest, hungry chicks beg repeatedly and parents adjust their feeding rate to the call rate of young. Repetitive calling also occurs in fledglings and in some mammals where offspring follow provisioners. It is not yet clear whether, in mobile systems with dispersed young where adults cannot compare the vocal behaviour of all young simultaneously, the calls represent a signal of need. We investigated repetitive begging by cooperatively reared meerkat, Suricata suricatta, pups that foraged with the group. Pups produced two types of begging calls: repeat calls over long periods and high-pitched calls mainly confined to feeding events. Food-deprived pups stayed closer to feeders, and begged for longer and more intensely by calling at a higher rate. Hungry pups increased both the rate of repeat calls, which were given continually, and the number of high-pitched bouts, but adults increased their food allocation only in relation to the rate of repeat calls. Our study indicates that hunger may lead to several changes in vocal behaviour, only some of which may be used by adults to assess need.

Calling in the gap: competition or cooperation in littermates' begging behaviour?

Abstract: Offspring are frequently raised alongside their siblings and are provisioned early in life by adults. Adult provisioning is stimulated by offspring begging, but it is unclear how each offspring should beg, given the begging behaviour of their siblings. It has previously been suggested that siblings may compete directly through begging for a fixed level of provisioning, or that siblings may cooperate in their begging in order to jointly elevate the level of provisioning by adults. We studied the begging behaviour of meerkat Suricata suricatta pups, explored how it changed as the begging behaviour of their littermates altered, and asked how the adults responded to group-level changes in begging. We found conflicting evidence for classic models of competitive and cooperative begging. Pups reared in larger litters begged at higher rates, yet experimentally increasing begging levels within groups caused individual begging rates to decrease. Pups decreased begging rates when close to other begging pups, and pups spaced further apart were fed more. Adults increased their overall level of provisioning as group levels of begging increased, but per capita provisioning decreased. Adults preferred to provision speakers playing back recordings of two pups begging alternately to recordings of the same two pups begging simultaneously. Therefore, we suggest that meerkat pups avoid some of the costs of direct competition imposed by an escalation of begging as other pups beg, by begging in gaps between the bouts of others or avoiding littermates. Such behaviour is also preferred by provisioning adults, thus providing additional benefits to the pups.

The effects of hexetidine (Oraldene (TM)) on the adherence of Candida albicans to human buccal epithelial cells in vitro and ex vivo and on in vitro morphogenesis

Purpose. This study reports the effects of hexetidine (Oraldene(TM)) on two virulence attributes of Candida albicans, namely, in vitro and ex vivo adherence of yeast cells to buccal epithelial cells (BEG) and in vitro morphogenesis.

PRELIMINARY INVESTIGATIONS CONCERNING THE ANTI-ADHERENCE PROPERTIES OF POLYHEXAMETHYLENEBIGUANIDE (VANTOCIL IB(TM))

The effect of polyhexamethylenebiguanide (PHMB) on adherence of Candida albicans blastospores to human buccal epithelial cells (BEG) was examined in vitro. Treatments of either blastospores or BEC with PHMB (50 and 1000 mu g ml(-1)) significantly reduced the number of adherent blastospores per BEC and increased the number of BEC devoid of blastospores.