The social roots of Einstein's theory of relativity

In its infancy the British Association for the Advancement of Science derived a good deal of its inspiration from the writings of Francis Bacon. But the pursuit of Baconian policies brought with it attendant dangers which critics from Charles Dickens to the Times were not slow to magnify. Although the situation was further complicated by the sensitiveness of institutional Christianity at the start of Victoria's reign, some of the hazards which the Association endured had to be accepted simply as consequences of the attempt to provide a secure platform for British science.     

Mourning dove numbers on different seral communities in the Chihuahuan Desert

Mourning Doves are the most commonly hunted game bird in New Mexico based on hunter harvest data collected by New Mexico Department of Game and Fish. Research is limited on the influence of rangeland ecological condition on Mourning Dove ( Zenaida macroura ) populations in the Chihuahuan Desert of New Mexico. Mourning Dove numbers were evaluated periodically (1988-1989) on ranges in late- and mid-seral conditions in south central New Mexico based on the Dyksterhuis quantitative climax procedure. Strip transect procedures were used to estimate Mourning Dove populations. Concurrently, vegetation canopy cover was determined by line intercept. On the basis of percent cover, grasses were the most abundant group on late-seral range while shrubs dominated mid-seral range. Mourning Dove sightings did not differ ( P > 0.05) between late- and mid-seral ranges, nor did they differ ( P > 0.05) among grassland, shrubland, and shrub-grass mosaic communities. Mourning Dove populations showed seasonal differences ( P < 0.05), with numbers highest in summer and fall and lowest in winter and spring. Data from our study indicate that Chihuahuan Desert ranges in either mid- or late-seral stages provide equally suitable habitat for Mourning Doves.     

Influence of environmental changes on degradation of chiral pollutants in soils.

Numerous anthropogenic chemicals of environmental concern--including some phenoxy acid herbicides, organophosphorus insecticides, polychlorinated biphenyls, phthalates, freon substitutes and some DDT derivatives--are chiral. Their potential biological effects, such as toxicity, mutagenicity, carcinogenicity, and endocrine disrupter activity, are generally enantiomer-selective, and different enantiomers are preferentially degraded (transformed) by micro-organisms in various environments. Here we use field and laboratory experiments to demonstrate that environmental changes in soils can alter these preferences, and to suggest that the preferences shift owing to different groups of related microbial genotypes being activated by different environmental changes. In Brazilian soils, almost all pasture samples preferentially transformed the non-herbicidal enantiomer of dichlorprop ((RS)-2-(2,4-dichlorophenoxy)propionic acid), while most forest samples either transformed the herbicidal enantiomer more readily or as rapidly as the non-herbicidal enantiomer. Organic nutrient enrichments shifted enantioselectivity for methyl dichlorprop ((RS)-methyl 2-(2,4-dichlorophenoxy)propionic acid) strongly towards preferentially removing the non-herbicidal enantiomer in soils from Brazil and North America, potentially increasing phytotoxicity of its residues relative to that of the racemate. Assessments of the risks chemical pollutants pose to public health and the environment need to take into account the chiral selectivity of microbial transformation processes and their alteration by environmental changes, especially for pesticides as up to 25 per cent are chiral.     

CD69 acts downstream of interferon-alpha/beta to inhibit S1P1 and lymphocyte egress from lymphoid organs

Naive lymphocytes continually enter and exit lymphoid organs in a recirculation process that is essential for immune surveillance. During immune responses, the egress process can be shut down transiently. When this occurs locally it increases lymphocyte numbers in the responding lymphoid organ; when it occurs systemically it can lead to immunosuppression as a result of the depletion of recirculating lymphocytes. Several mediators of the innate immune system are known to cause shutdown, including interferon alpha/beta (IFN-alpha/beta) and tumour necrosis factor, but the mechanism has been unclear. Here we show that treatment with the IFN-alpha/beta inducer polyinosine polycytidylic acid (hereafter 'poly(I:C)') inhibited egress by a mechanism that was partly lymphocyte-intrinsic. The transmembrane C-type lectin CD69 was rapidly induced and CD69-/- cells were poorly retained in lymphoid tissues after treatment with poly(I:C) or infection with lymphocytic choriomeningitis virus. Lymphocyte egress requires sphingosine 1-phosphate receptor-1 (S1P1), and IFN-alpha/beta was found to inhibit lymphocyte responsiveness to S1P. By contrast, CD69-/- cells retained S1P1 function after exposure to IFN-alpha/beta. In coexpression experiments, CD69 inhibited S1P1 chemotactic function and led to downmodulation of S1P1. In a reporter assay, S1P1 crosslinking led to co-crosslinking and activation of a CD69-CD3zeta chimaera. CD69 co-immunoprecipitated with S1P1 but not the related receptor, S1P3. These observations indicate that CD69 forms a complex with and negatively regulates S1P1 and that it functions downstream of IFN-alpha/beta, and possibly other activating stimuli, to promote lymphocyte retention in lymphoid organs.     

The DNA sequence, annotation and analysis of human chromosome 3

After the completion of a draft human genome sequence, the International Human Genome Sequencing Consortium has proceeded to finish and annotate each of the 24 chromosomes comprising the human genome. Here we describe the sequencing and analysis of human chromosome 3, one of the largest human chromosomes. Chromosome 3 comprises just four contigs, one of which currently represents the longest unbroken stretch of finished DNA sequence known so far. The chromosome is remarkable in having the lowest rate of segmental duplication in the genome. It also includes a chemokine receptor gene cluster as well as numerous loci involved in multiple human cancers such as the gene encoding FHIT, which contains the most common constitutive fragile site in the genome, FRA3B. Using genomic sequence from chimpanzee and rhesus macaque, we were able to characterize the breakpoints defining a large pericentric inversion that occurred some time after the split of Homininae from Ponginae, and propose an evolutionary history of the inversion.     

Microperiodic structures: direct writing of three-dimensional webs

Applications are emerging that require the creation of fine-scale structures in three dimensions--examples include scaffolds for tissue engineering, micro-fluidic devices and photonic materials that control light propagation over a range of frequencies. But writing methods such as dip-pen nanolithography and ink-jet printing are either confined to two dimensions or beset by wetting and spreading problems. Here we use concentrated polyelectrolyte inks to write three-dimensional microperiodic structures directly without using masks. Our technique enables us to write arbitrary three-dimensional patterns whose features are nearly two orders of magnitude smaller than those attained with other multilayer printing techniques.