Coverage dependence of the 1-propanol adsorption on the Si(001) surface and fragmentation dynamics

The geometric, electronic, energetic, and dynamic properties of 1-propanol adsorbed on the Si(001)-2x1 surface are studied from first principles by use of a slab approach. The 1-propanol molecule initially interacts with the Si surface through formation of a dative bond, subsequently the physisorbed 1-propanol molecule reacts with the surface by cleavage of the O-H bond, and the Si(001)-2x1 surface undergoes further reconstruction as a result of the adsorption of the organic species. The band structure and density of states (DOS) are first analyzed for this system. The band gap of the Si/1-propanol film increases as the coverage level is enhanced. Good agreement is found with available experimental data.Comment: 29 pages, 15 figures, 8 tables, submitted to Phys. Rev.

Gender Sensitive Blindness Prevention Intervention in the Niger Delta Region of Nigeria II: A report of a free cataract surgical service for women

Background: Gender issues in eye care are a global priority. Women have been recognized to face challenges in eye care. This includes a higher prevalence of disease conditions such as cataract to service delivery in which it is noted that they take up services especially for cataract surgery less than their male counterpart. This report seeks to document the experience and outcome of this organized gender-sensitive eye care project and in addition, make recommendations for future gender programmes. Women in the state were invited to participate in a free cataract surgical eye camp project. A talk on HIV was given at each centre and women willing to have free HIV testing were tested and counselled accordingly. Methods: A total of four thousand two hundred and thirty nine (4239) women were examined between 1st July and 30th September 2007. Eye operations were performed on 261 ( 6%) women during the duration of this project. Extra capsular cataract surgery with intraocular lens implantation was performed in 185 out of the 261 eye surgeries. Of the 4239 women who presented, a total of nine hundred and twenty three women (923) voluntarily screened for HIV. Out of these, thirty eight (38) women tested positive, of which 35 accepted counselling and commenced treatment. Two thousand five hundred and sixty-six (2566) 61% of participants at the eye camp were given reading glasses; most of these women were civil servants (teachers). Results: A female only surgical cataract eye camp is possible. It is convenient, economical and beneficial to have a collaborative programme with the committee on HIV/AIDS. This project was a successful strategy to reduce blindness, poverty and ensure empowerment of women. Recommendations are made towards a holistic approach in the organization of cataract surgical eye camps and for women.Key words: female, HIV, cataract, community eye cam

Prevention of Childhood Blindness through the Integration with Maternal Eye Care Programmes

Objective: The prevention of childhood blindness through the provision of preventive services at the community level, specialized surgical services in ophthalmic units and the provision of devices to correct low and services to children with established visual loss. Materials and methods: A series of free surgical cataract eye camps which focused on only women were conducted throughout Delta State in which children with eye problems were incidentally identified and treated. Of the 4239 women seen, 1006 (24%) brought their children along with them. Out of the 1006 children that accompanied their mothers, 840 (83%) of the children were seen based on their the request of their mothers for their ocular examination. Of these children, 28 (3%) had ocular morbidity. There were 19 boys and 9 girls. The majority of the children were between 2 to 5 years of age. The commonest causes of ocular morbidity were congenital and developmental cataract (24%), vernal conjunctivitis (28%), congenital glaucoma (14%) and corneal opacity from measles, harmful traditional eye practises and severe vernal keratoconjunctivitis. Others were refractive error, strabismus and optic atrophy. Results: A total of 10 children underwent surgery. Surgical procedures included 4 lensectomy and 3 lensectomy with intraocular lens implantation, 2 trabeculectomy and 1 optical iridectomy. One patient was given spectacles for juvenile onset myopia. Conclusion: there is a potential for a female gender focused eye programme, to promote child eye health and prevent childhood blindness.Key words: childhood blindness; community; cataract; glaucom

Vultures of the Seas: Hyperacidic Stomachs in Wandering Albatrosses as an Adaptation to Dispersed Food Resources, including Fishery Wastes

Animals are primarily limited by their capacity to acquire food, yet digestive performance also conditions energy acquisition, and ultimately fitness. Optimal foraging theory predicts that organisms feeding on patchy resources should maximize their food loads within each patch, and should digest these loads quickly to minimize travelling costs between food patches. We tested the prediction of high digestive performance in wandering albatrosses, which can ingest prey of up to 3 kg, and feed on highly dispersed food resources across the southern ocean. GPS-tracking of 40 wandering albatrosses from the Crozet archipelago during the incubation phase confirmed foraging movements of between 475–4705 km, which give birds access to a variety of prey, including fishery wastes. Moreover, using miniaturized, autonomous data recorders placed in the stomach of three birds, we performed the first-ever measurements of gastric pH and temperature in procellariformes. These revealed surprisingly low pH levels (average 1.50±0.13), markedly lower than in other seabirds, and comparable to those of vultures feeding on carrion. Such low stomach pH gives wandering albatrosses a strategic advantage since it allows them a rapid chemical breakdown of ingested food and therefore a rapid digestion. This is useful for feeding on patchy, natural prey, but also on fishery wastes, which might be an important additional food resource for wandering albatrosses

Allotetraploid Origin and Divergence in Eleusine (Chloridoideae, Poaceae): Evidence from Low-copy Nuclear Gene Phylogenies and a Plastid Gene Chronogram

Background and Aims: Eleusine (Poaceae) is a small genus of the subfamily Chloridoideae exhibiting considerable morphological and ecological diversity in East Africa and the Americas. The interspecific phylogenetic relationships of Eleusine are investigated in order to identify its allotetraploid origin, and a chronogram is estimated to infer temporal relationships between palaeoenvironment changes and divergence of Eleusine in East Africa. Methods: Two low-copy nuclear (LCN) markers, Pepc4 and EF-1a, were analysed using parsimony, likelihood and Bayesian approaches. A chronogram of Eleusine was inferred from a combined data set of six plastid DNA markers (ndhA intron, ndhF, rps16-trnK, rps16 intron, rps3, and rpl32-trnL) using the Bayesian dating method. Key Results: The monophyly of Eleusine is strongly supported by sequence data from two LCN markers. In the cpDNA phylogeny, three tetraploid species (E. africana, E. coracana and E. kigeziensis) share a common ancestor with the E. indica–E. tristachya clade, which is considered a source of maternal parents for allotetraploids. Two homoeologous loci are isolated from three tetraploid species in the Pepc4 phylogeny, and the maternal parents receive further support. The A-type EF-1a sequences possess three characters, i.e. a large number of variations of intron 2; clade E-A distantly diverged from clade E-B and other diploid species; and seven deletions in intron 2, implying a possible derivation through a gene duplication event. The crown age of Eleusine and the allotetraploid lineage are 3.89 million years ago (mya) and 1.40 mya, respectively. Conclusions: The molecular data support independent allotetraploid origins for E. kigeziensis and the E. africana–E. coracana clade. Both events may have involved diploids E. indica and E. tristachya as the maternal parents, but the paternal parents remain unidentified. The habitat-specific hypothesis is proposed to explain the divergence of Eleusine and its allotetraploid lineage

Molecular Signatures Reveal Circadian Clocks May Orchestrate the Homeorhetic Response to Lactation

Genes associated with lactation evolved more slowly than other genes in the mammalian genome. Higher conservation of milk and mammary genes suggest that species variation in milk composition is due in part to the environment and that we must look deeper into the genome for regulation of lactation. At the onset of lactation, metabolic changes are coordinated among multiple tissues through the endocrine system to accommodate the increased demand for nutrients and energy while allowing the animal to remain in homeostasis. This process is known as homeorhesis. Homeorhetic adaptation to lactation has been extensively described; however how these adaptations are orchestrated among multiple tissues remains elusive. To develop a clearer picture of how gene expression is coordinated across multiple tissues during the pregnancy to lactation transition, total RNA was isolated from mammary, liver and adipose tissues collected from rat dams (n = 5) on day 20 of pregnancy and day 1 of lactation, and gene expression was measured using Affymetrix GeneChips. Two types of gene expression analysis were performed. Genes that were differentially expressed between days within a tissue were identified with linear regression, and univariate regression was used to identify genes commonly up-regulated and down-regulated across all tissues. Gene set enrichment analysis showed genes commonly up regulated among the three tissues enriched gene ontologies primary metabolic processes, macromolecular complex assembly and negative regulation of apoptosis ontologies. Genes enriched in transcription regulator activity showed the common up regulation of 2 core molecular clock genes, ARNTL and CLOCK. Commonly down regulated genes enriched Rhythmic process and included: NR1D1, DBP, BHLHB2, OPN4, and HTR7, which regulate intracellular circadian rhythms. Changes in mammary, liver and adipose transcriptomes at the onset of lactation illustrate the complexity of homeorhetic adaptations and suggest that these changes are coordinated through molecular clocks