Habitat Composition and Connectivity Predicts Bat Presence and Activity at Foraging Sites in a Large UK Conurbation

Background: Urbanization is characterized by high levels of sealed land-cover, and small, geometrically complex, fragmented land-use patches. The extent and density of urbanized land-use is increasing, with implications for habitat quality, connectivity and city ecology. Little is known about densification thresholds for urban ecosystem function, and the response of mammals, nocturnal and cryptic taxa are poorly studied in this respect. Bats (Chiroptera) are sensitive to changing urban form at a species, guild and community level, so are ideal model organisms for analyses of this nature. Methodology/Principal Findings: We surveyed bats around urban ponds in the West Midlands conurbation, United Kingdom (UK). Sites were stratified between five urban land classes, representing a gradient of built land-cover at the 1 km 2 scale. Models for bat presence and activity were developed using land-cover and land-use data from multiple radii around each pond. Structural connectivity of tree networks was used as an indicator of the functional connectivity between habitats. All species were sensitive to measures of urban density. Some were also sensitive to landscape composition and structural connectivity at different spatial scales. These results represent new findings for an urban area. The activity of Pipistrellus pipistrellus (Schreber 1774) exhibited a non-linear relationship with the area of built land-cover, being much reduced beyond the threshold of,60 % built surface. The presence of tree networks appears to mitigate the negative effects of urbanization for this species

The incidence of cancer in people with intellectual disabilities

Objective: During the last 50 years there have been significant improvements in life expectancy among people with intellectual disability (ID), and so their incidence of age-associated diseases, such as cancer, is rising. The aim of this study was to compare the rate of cancer in people with ID with that found in the general population. Methods: Information on 9409 individuals registered with the Disability Services Commission of Western Australia was linked to the State Cancer Registry, with 200 cases of cancer detected over 156,729 person-years. Standardised incidence ratios (SIRs) and 95% confidence intervals were calculated for both sexes separately by 5-year age groups for the period 1982–2001. The same procedures were adopted in the estimation of SIRs for specific types of cancers. Results: The age-standardised incidence of all cancers in people with ID was not significantly different from the general population. However, males with ID were observed to have a significantly increased risk of leukaemia, brain and stomach cancers, and a reduced risk of prostate cancer, while leukaemia, corpus uteri and colorectal cancers were significantly higher in females. Conclusions: Health practitioners need to be aware that with improvements in life expectancy the incidence of cancer in people with ID is likely to rise. More proactive health promotion campaigns may be needed for people with ID, who are likely to be poor users of screening services and whose symptoms may not be reported until they are in more advanced, less treatable stages of disease

Symmetry breaking: polymorphic form selection by enantiomers of the melatonin agonist and its missing polymorph

Synthesis of a melatonin agonist for treatment of sleep disorders produced a pair of enantiomers, of which one is biologically active. Two polymorphs were discovered using the inactive enantiomer, conserving the active enantiomer for toxicological testing. Later studies with the active enantiomer yielded only the metastable form, despite more than 1000 attempts to isolate the stable form. The difficulty is surprising, since the stable form is favored by 0.7 kcal mol–1, which is toward the extreme for stability differences between organic polymorphs. Study of individual enantiomers allowed the phase behavior of polymorphs of greatly different energy to be examined without interconversion. A number of unusual features are noted. After the stable polymorph of the inactive enantiomer was nucleated, the metastable form became very difficult to isolate. The metastable form converts into a less soluble monohydrate structure in water, whereas the stable polymorph does not due to its reduced activity. Both chiral polymorphs are denser than the racemic crystalline form at low temperature, the stable form being at the extreme for chiral-racemic pairs. Free energy-temperature relations predict “spontaneous resolution” of the racemic crystalline form into a conglomerate mixture of stable polymorph at low temperature. The unusual characteristics of the system are explained by hydrogen bonding and conformational flexibility of the molecule. Ab initio calculations aid in understanding the relative contributions of these interactions to the lattice energies and the role that conformational energy differences play in the polymorphic stability. This system highlights the importance of the creation of the very first nuclei of a crystalline form. The reluctance of the stable form to nucleate is attributed to a large energy difference between polymorphic forms. The large interfacial tension for primary nucleation reduces the probability of forming clusters of size sufficient for favorable growth in the absence of heterogeneous nucleation. This study highlights how nucleation of a new form can revise the readily “accessible” region of a compound’s crystal form landscape