Low-Energy Physics Reach of Xenon Detectors for Nuclear-Recoil-Based Dark Matter and Neutrino Experiments.

Dual-phase xenon detectors lead the search for keV-scale nuclear recoil signals expected from the scattering of weakly interacting massive particle (WIMP) dark matter, and can potentially be used to study the coherent nuclear scattering of MeV-scale neutrinos. New capabilities of such experiments can be enabled by extending their nuclear recoil searches down to the lowest measurable energy. The response of the liquid xenon target medium to nuclear recoils, however, is not well characterized below a few keV, leading to large uncertainties in projected sensitivities. In this work, we report a new measurement of ionization signals from nuclear recoils in liquid xenon down to the lowest energy reported to date. At 0.3 keV, we find that the average recoil produces approximately one ionization electron; this is the first measurement of nuclear recoil signals at the single-ionization-electron level, approaching the physical limit of liquid xenon ionization detectors. We discuss the implications of these measurements on the physics reach of xenon detectors for nuclear-recoil-based WIMP dark matter searches and the detection of coherent elastic neutrino-nucleus scattering.

Molecular DNA identification of medicinal plants used by traditional healers in Malaysia.

Plants have been used throughout human history for food and medicine. However, many plants are toxic, and cannot easily be morphologically distinguished from non-toxic plants. DNA identification solves this problem and is widely used. Nonetheless, plant DNA barcode identification faces a number of challenges, and many studies have been conducted to find suitable barcodes. The present study was conducted to test the efficiency of commonly used primers, namely ITS2, rpoC1, and trnH-psbA, in order to find the best DNA barcode markers for the identification of medicinal plants in Malaysia. Fresh leaves from 12 medicinal plants that are commonly used by Malay traditional healers were collected from the Tropical Spice Garden, Pulau Pinang, and subjected to polymerase chain reaction amplification using ITS2, rpoC1, and trnH-psbA DNA markers. We found that trnH-psbA is the best DNA marker for the species-level identification of medicinal plants in Malaysia.

Movement patterns and genetic diversity of wild and reintroduced common dormice, Muscardinus avellanarius.

Movement is an important life history trait that can have an impact on local adaptation, and other evolutionary phenomena. We used a combination of nestbox survey data and genetic techniques (genotyping at 10 microsatellite loci) to quantify patterns of movement in common dormice Muscardinus avellanarius at two distinct sites in the UK: 1) Bontuchel (a natural population) and 2) Wych (captive-bred individuals that were reintroduced to this site), over three consecutive years (2006-2008). Both methods revealed a consistent pattern of sex-biased movement (movements by adult males and females) in both populations that allowed isolation-by-distance genetic structure to develop within 1 km. The similarity of data from captive-bred and natural individuals indicated that ex situ programing has not significantly altered the natural movement behavior of common dormice; consequently, the two populations could be managed with the same conservation strategies. We also found that the reintroduced dormice in Wych maintained relatively high levels of genetic diversity. This first report of movement patterns in reintroduced and natural populations of M. avellanarius combining genetic and field-survey data highlights the role of genetic studies in the investigation of ecological behaviour and for conservation management.

Non-invasive sex identification of the white-bellied sea eagle (Haliaeetus leucogaster) through genetic analysis of feathers.

The white-bellied sea eagle, Haliaeetus leucogaster, displays reversed sexual size dimorphism and is monomorphic for adult plumage coloration. Early attempts to identify sex in sexually monomorphic birds were based on morphological or chromosomal characters, but since avian W-specific DNA sequences were identified, PCR amplification has become commonly used for molecular sexing. We used a PCR test employing primers that amplify two homologous fragments of both the CHD-W gene, unique to females, and the CHD-Z gene, occurring in both sexes. This test was applied to five individuals of H. leucogaster from the Malacca Zoo and to male and female domestic chickens, Gallus domesticus, for comparison. All individuals were sexed successfully with high reproducibility. We conclude that this PCR-based test with feathers as the DNA source is a reliable sexing method for H. leucogaster. This sexing technique is objective and non-invasive and could be used to test sex ratio theories, as well as to help improve conservation and management actions for captive breeding program of this species in Malaysia.

Inflammatory changes in conjunctival scrapings after allergen provocation in humans.

This study was performed to investigate the inflammatory changes occurring in the human conjunctiva at different time periods after allergen provocation. Twenty-three ryegrass-sensitive patients with allergic conjunctivitis (19 with hayfever and four with vernal conjunctivitis) were challenged by topical administration of ryegrass antigen to the eye. Allergen concentrations were increased in increments until an immediate ocular allergic reaction was elicited. Numbers of various inflammatory cells (neutrophils, eosinophils, lymphocytes, and monocytes) found in conjunctival scrapings were quantified and correlated with the clinical profile, total serum IgE, and serum IgE to Rye I antigen. Twenty minutes after some level of antigen topical challenge to the eye, all patients had ocular redness, tearing, and itching. Compared with findings in seven control subjects, significant inflammatory cells were found in the conjunctival scrapings of patients before challenge (p less than 0.05) and 20 minutes (p less than 0.001) and 6 hours (p less than 0.002) after effective challenge. Significant increases in neutrophils of patients occurred after 20 minutes (p less than 0.001), and in eosinophils at 6 hours (p less than 0.005), compared with values of control subjects. When each case was evaluated individually, nine of the 23 patients had highly evident inflammatory changes 6 hours after allergen provocation. The levels of total serum IgE and serum IgE to Rye I antigen of these nine patients did not differ significantly from the other patients in the study. Our data provide the first evidence in humans that significant inflammatory changes in conjunctival scrapings are present long after allergen exposure has ended.