From gyroscopic to thermal motion: a crossover in the dynamics of molecular superrotors

Localized heating of a gas by intense laser pulses leads to interesting acoustic, hydrodynamic and optical effects with numerous applications in science and technology, including controlled wave guiding and remote atmosphere sensing. Rotational excitation of molecules can serve as the energy source for raising the gas temperature. Here, we study the dynamics of energy transfer from the molecular rotation to heat. By optically imaging a cloud of molecular superrotors, created with an optical centrifuge, we experimentally identify two separate and qualitatively different stages of its evolution. The first non-equilibrium "gyroscopic" stage is characterized by the modified optical properties of the centrifuged gas - its refractive index and optical birefringence, owing to the ultrafast directional molecular rotation, which survives tens of collisions. The loss of rotational directionality is found to overlap with the release of rotational energy to heat, which triggers the second stage of thermal expansion. The crossover between anisotropic rotational and isotropic thermal regimes is in agreement with recent theoretical predictions and our hydrodynamic calculations

Effects of Organic and Conventional Agricultural Practices on Soil Microbial Communities and Molecular Detection of Soil Borne Disease

Agricultural practices affect soil microbial communities and health through the input of pesticides, herbicides, fertilizers, and cycling of crop rotation. By examining the microbial community structure, we analyzed how microbial species respond to the environment that individual farms create. Early detection of soil borne disease is essential for agricultural success. However, monitoring incidence of disease based on plant growth response to pathogenic inoculation may not reveal the amount of pathogenic DNA in soil. A comparative study of tomato production systems was conducted by analysis of soil microbial community structure from four farms in Southeast Georgia for the years 2012 and 2013, and incidence level of disease and plant growth of tomato plants grown in greenhouse soil were measured. The results indicated that the soil fungal, bacterial, and animal communities were unique to each farm (ANOSIM PSclerotiumrolfsii DNA (P=0.0454 and P=0.0278 respectively) in the inoculated than un-inoculated soil measured by quantitative polymerase chain reaction (Q-PCR). Fluorescent in situ hybridization (FISH) was used as an alternative for visual detection of Sclerotium rolfsii through whole cell hybridization. A higher hybridization signal was detected in soil with high Sclerotium DNA (15.55333 pg/µl) than in soil with low Sclerotium DNA (0.0155 pg/µl). In conclusion, this study suggested that farming management practices have an effect on the microbial community structure and chemical components of agricultural soil and that plant growth in a greenhouse setting was not a clear representation of the amount of pathogenic DNA in the soil. Molecular detection of pathogenic DNA in soil could provide important information on predicting the potential for disease development in agricultural ecosystems. Key words: Microbial community structure, Q-PCR, FISH, Sclerotium rolfsii, Soil borne diseas

Child welfare specialists and secondary traumatic stress : the effects of empathetic caring : a phenomenological study.

Working with abused and neglected children is one of the most difficult jobs imaginable. The stressful conditions of a Child Welfare Specialist or supervisor are enormous and they often internalize the traumatic stress of their young clients and their families. This type of traumatic stress, referred to as Secondary Traumatic Stress (STS), inputs its toll on these employees each and every day making their jobs even more difficult. The research on this topic shows that positive coping mechanisms and peer support are greatly effective at combatting STS and the anxiety, depression and physical ailments that it produces. The main focus of this phenomenological study is to examine the ways STS affects the Child Welfare Specialists and supervisors of the Oklahoma Department of Human Services (OKDHS). It also seeks to find which positive and negative coping mechanisms are being applied to combat this type of stress and in what ways the agency can make changes to better care for its Child Welfare front-line staff and their mental health needs. Ten front-line employees of the OKDHS Child Welfare Services division were recruited to participate in an interview regarding their experiences as Child Welfare Specialists. Two common themes emerged after reviewing the interview transcriptions and selective highlighting: The need for accessible mental health resources and specialized training. Counseling for workers who experience the effects of STS should be available and easily accessible. The current arrangement for mental health services is not conducive to those employees working 40+ hour work weeks, on-call and weekend hours. A need for more specialized training is also a factor. Workers leaving CORE (specialized training for new Child Welfare staff) often feel completely unprepared for the realities of a child welfare caseload and the trauma they will face

Religious Relationships with the Environment in a Tibetan Rural Community : Interactions and Contrasts with Popular Notions of Indigenous Environmentalism

Acknowledgments: We thank Beijing Forestry University, our field assistants Tashi Rabden, Pema Dechin, Tsewang Chomtso and Gele Chopel for their invaluable help, the Forest Bureau of Daocheng county for permission and support, and the people of Samdo for their hospitality and participation. The research was funded by the ESRC and the World Pheasant Association. This paper is a contribution to Imperial College’s Grand Challenges in Ecosystems and the Environment initiative. Two anonymous reviewers gave valuable comments on the manuscript.Peer reviewedPublisher PD

Transverse "resistance overshoot" in a Si/SiGe two-dimensional electron gas in the quantum Hall effect regime

We investigate the peculiarities of the "overshoot" phenomena in the transverse Hall resistance R_{xy} in Si/SiGe. Near the low magnetic field end of the quantum Hall effect plateaus, when the filling factor \nu approaches an integer i, R_{xy} overshoots the normal plateau value h/ie^2. However, if magnetic field B increases further, R_{xy} decreases to its normal value. It is shown that in the investigated sample n-Si/Si_{0.7}Ge_{0.3}, overshoots exist for almost all \nu. Existence of overshoot in R_{xy} observed in different materials and for different \nu, where splitting of the adjacent Landau bands has different character, hints at the common origin of this effect. Comparison of the experimental curves R_{xy}(\nu) for \nu = 3 and \nu = 5 with and without overshoot showed that this effect exist in the whole interval between plateaus, not only in the region where R_{xy} exceeds the normal plateau value.Comment: 3 pages, 5 EPS figure

A Mesolithic settlement site at Howick, Northumberland: a preliminary report

Excavations at a coastal site at Howick during 2000 and 2002 have revealed evidence for a substantial Mesolithic settlement and a Bronze Age cist cemetery. Twenty one radiocarbon determinations of the earlier eighth millennium BP (Cal.) indicate that the Mesolithic site is one of the earliest known in northern Britain. An 8m core of sediment was recovered from stream deposits adjacent to the archaeological site which provides information on local environmental conditions. Howick offers a unique opportunity to understand aspects of hunter-gatherer colonisation and settlement during a period of rapid palaeogeographical change around the margins of the North Sea basin, at a time when it was being progressively inundated by the final stages of the postglacial marine transgression. The cist cemetery will add to the picture of Bronze Age occupation of the coastal strip and again reveals a correlation between the location of Bronze Age and Mesolithic sites which has been observed elsewhere in the region

On Observing Dynamic Prioritised Actions in SOC

We study the impact on observational semantics for SOC of priority mechanisms which combine dynamic priority with local pre-emption. We define manageable notions of strong and weak labelled bisimilarities for COWS, a process calculus for SOC, and provide alternative characterisations in terms of open barbed bisimilarities. These semantics show that COWS’s priority mechanisms partially recover the capability to observe receive actions (that could not be observed in a purely asynchronous setting) and that high priority primitives for termination impose specific conditions on the bisimilarities

Higher physical fitness levels are associated with less language decline in healthy ageing

Healthy ageing is associated with decline in cognitive abilities such as language. Aerobic fitness has been shown to ameliorate decline in some cognitive domains, but the potential benefits for language have not been examined. In a cross-sectional sample, we investigated the relationship between aerobic fitness and tip-of-the-tongue states. These are among the most frequent cognitive failures in healthy older adults and occur when a speaker knows a word but is unable to produce it. We found that healthy older adults indeed experience more tip-of-the-tongue states than young adults. Importantly, higher aerobic fitness levels decrease the probability of experiencing tip-of-the-tongue states in healthy older adults. Fitness-related differences in word finding abilities are observed over and above effects of age. This is the first demonstration of a link between aerobic fitness and language functioning in healthy older adults

On Asynchronous Session Semantics

This paper studies a behavioural theory of the π-calculus with session types under the fundamental principles of the practice of distributed computing — asynchronous communication which is order-preserving inside each connection (session), augmented with asynchronous inspection of events (message arrivals). A new theory of bisimulations is introduced, distinct from either standard asynchronous or synchronous bisimilarity, accurately capturing the semantic nature of session-based asynchronously communicating processes augmented with event primitives. The bisimilarity coincides with the reduction-closed barbed congruence. We examine its properties and compare them with existing semantics. Using the behavioural theory, we verify that the program transformation of multithreaded into event-driven session based processes, using Lauer-Needham duality, is type and semantic preserving