Laser induced photoluminescence spectroscopy of cometary radicals

Flash photolysis together with laser excitation of the product fragments was used in laboratory studies of cometary radicals. The LIPS method has been applied to the CN radical to determine: (1) Radiative lifetimes of individual rotational levels in the zeroth vibrational level of the B state; (2) energy partitioning during photodissociation of C2N2; and (3) vibrational and rotational excitation during formation of CN radicals in the photodissociation of dicyanoacetylene

Optimal search strategies for hidden targets

What is the fastest way of finding a randomly hidden target? This question of general relevance is of vital importance for foraging animals. Experimental observations reveal that the search behaviour of foragers is generally intermittent: active search phases randomly alternate with phases of fast ballistic motion. In this letter, we study the efficiency of this type of two states search strategies, by calculating analytically the mean first passage time at the target. We model the perception mecanism involved in the active search phase by a diffusive process. In this framework, we show that the search strategy is optimal when the average duration of "motion phases" varies like the power either 3/5 or 2/3 of the average duration of "search phases", depending on the regime. This scaling accounts for experimental data over a wide range of species, which suggests that the kinetics of search trajectories is a determining factor optimized by foragers and that the perception activity is adequately described by a diffusion process.Comment: 4 pages, 5 figures. to appear in Phys. Rev. Let

Bearing witness and being bounded; the experiences of nurses in adult critical care in relation to the survivorship needs of patients and families

Aim: To discern and understand the responses of nurses to the survivorship needs of patients and family members in adult critical care units. Background: The critical care environment is a demanding place of work which may limit nurses to immediacy of care, such is the proximity to death and the pressure of work. Design: A constructivist grounded theory approach with constant comparative analysis. Methods: As part of a wider study and following ethical approval, eleven critical care nurses working within a general adult critical care unit were interviewed with respect to their experiences in meeting the psychosocial needs of patients and family members. Through the process of constant comparative analysis an overarching selective code was constructed. EQUATOR guidelines for qualitative research (COREQ) applied. Results: The data illuminated a path of developing expertise permitting integration of physical, psychological and family care with technology and humanity. Gaining such proficiency is demanding and the data presented reveals the challenges that nurses experience along the way. Conclusion: The study confirms that working within a critical care environment is an emotionally charged challenge and may incur an emotional cost. Nurses can find themselves bounded by the walls of the critical care unit and experience personal and professional conflicts in their role. Nurses bear witness to the early stages of the survivorship trajectory but are limited in their support of ongoing needs. Relevance to Clinical Practice: Critical care nurses can experience personal and professional conflicts when caring for both patients and families. This can lead to moral distress and may contribute to compassion fatigue. Critical care nurses appear bounded to the delivery of physiological and technical care, in the moment, as demanded by the patient's acuity. Consequentially this limits nurses’ ability to support the onward survivorship trajectory. Increased pressure and demands on critical care beds has contributed further to occupational stress in this care setting

New Records of Vascular Plants in the Yukon Territory VIII

Forty-seven taxa, 35 native and 12 introduced, are reported as new to the flora of Yukon and nine taxa previously reported are deleted. The new native taxa are: Artemisia arctica ssp. comata, Botrychium alaskense, Botrychium minganense, Bromus richardsonii, Calamagrostis holmii, Carex incurviformis, Carex mackenziei, Carex microchaeta ssp. nesophila, Carex ramenskii, Carex rariflora var. androgyna, Carex tahoensis, Carex xerantica, Carex × flavicans, Deschampsia sukatschewii, Eleocharis erythropoda, Eleocharis macrostachya, Eleocharis mamillata, Erigeron ochroleucus, Impatiens noli-tangere, Limnorchis huronensis, Nymphaea tetragona, Polygonum douglasii ssp. douglasii, Potamogeton natans, Potentilla crebridens ssp. hemicryophila, Puccinellia tenella ssp. langeana, Rumex beringensis, Salix farriae, Salix glauca ssp. Stipuli fera, Saussurea nuda, Saxifraga hyperborea, Saxifraga rivularis ssp. arctolitoralis, Silene soczavana var. macrosperma, Symphyotrichum subspicatum, Taraxacum hyparcticum, and Zannichellia palustris. The new introduced taxa are: Acer negundo, Avena fatua, Camelina microcarpa, Crepis capillaris, Hippophae rhamnoides, Lamium amplexicaule, Linaria dalmatica, Medicago lupulina, Prunus padus, Rumex pseudonatronatus, Valeriana officinale, and Viola tricolor. Deleted taxa are: Aster laevis var. geyeri, Carex athrostachya, Elatine triantha, Camelina sativa, Erysimum cheiri, Galium palustre, Impatiens capensis, Platanthera hyperborea, and Sonchus oleraceus. Vouchers are cited and general notes on distribution and identification are provided. Four of the native taxa reported here are new to Canada: Botrychium alaskense, Carex microchaeta ssp. nesophila, Potentilla crebridens ssp. hemicryophila and Rumex beringensis

High-Throughput Drug Screening Identifies a Potent Wnt Inhibitor that Promotes Airway Basal Stem Cell Homeostasis.

Mechanisms underpinning airway epithelial homeostatic maintenance and ways to prevent its dysregulation remain elusive. Herein, we identify that β-catenin phosphorylated at Y489 (p-β-cateninY489) emerges during human squamous lung cancer progression. This led us to develop a model of airway basal stem cell (ABSC) hyperproliferation by driving Wnt/β-catenin signaling, resulting in a morphology that resembles premalignant lesions and loss of ciliated cell differentiation. To identify small molecules that could reverse this process, we performed a high-throughput drug screen for inhibitors of Wnt/β-catenin signaling. Our studies unveil Wnt inhibitor compound 1 (WIC1), which suppresses T-cell factor/lymphoid enhancer-binding factor (TCF/LEF) activity, reduces ABSC proliferation, induces ciliated cell differentiation, and decreases nuclear p-β-cateninY489. Collectively, our work elucidates a dysregulated Wnt/p-β-cateninY489 axis in lung premalignancy that can be modeled in vitro and identifies a Wnt/β-catenin inhibitor that promotes airway homeostasis. WIC1 may therefore serve as a tool compound in regenerative medicine studies with implications for restoring normal airway homeostasis after injury

Deer reduce habitat quality for a woodland songbird: evidence from settlement patterns, demographic parameters, and body condition.

Understanding avian responses to ungulate-induced habitat modification is important because deer populations are increasing across much of temperate Europe and North America. Our experimental study examined whether habitat quality for Blackcaps (Sylvia atricapilla) in young woodland in eastern England was affected by deer, by comparing Blackcap behavior, abundance, and condition between paired plots (half of each pair protected from deer). The vegetation in each pair of plots was the same age. The Blackcap is an ideal model species for testing effects of deer on avian habitat quality because it is dependent on dense understory vegetation and is abundant throughout much of Europe. We compared timing of settlement, abundance, age structure (second-year vs. after-second-year), and phenotypic quality (measured as a body condition index, body mass divided by tarsus length) between experimental and control plots. We used point counts to examine Blackcap distribution, and standardized mist netting to collect demographic and biometric data. Incidence of singing Blackcaps was higher in nonbrowsed than in browsed plots, and singing males were recorded in nonbrowsed plots earlier in the season, indicating earlier and preferential territory establishment. Most Blackcaps, both males and females, were captured in vegetation prior to canopy closure (2–4 years of regrowth). Body condition was superior for male Blackcaps captured in nonbrowsed plots; for second-year males this was most marked in vegetation prior to canopy closure. We conclude that deer browsing in young woodland can alter habitat quality for understory-dependent species, with potential consequences for individual fitness and population productivity beyond the more obvious effects on population density

Validity of the Bottle Buoyancy Model for Body Fat Determination

International Journal of Exercise Science 10(1): 87-96, 2017. We investigated a modification of the bottle buoyancy (BB) method in comparison to single frequency, bioelectric impedance analysis (BIA) as a valid noninvasive method of percent body fat (%BF) determination. Twenty-eight participants (15 men, 13 women), in counterbalanced-order, completed the BB, BIA, and computerized hydrostatic densitometry (HD) methods. We elected to modify the BB method using a 12.15 L container with participants hugging the container in an upright position. Consistency measures of intraclass correlation coefficient (ICC), typical error (TE), coefficient of variation (CV) and total error of measurement (TEM) are reported. Our modification of the BB resulted in less “bobbing” than described in the previous method, and took ~5 to 15 min per participant to complete. Group values (%BF) did not differ (p \u3e 0.05) for BB (20.7 ± 6.6), BIA (21.0 ± 9.7), and HD (20.2 ± 7.2). Strong measurement agreement was observed between BB and HD (ICC: 0.95, TE: 1.80 %BF, CV: 10.7%, TEM: 1.77 %BF). Agreement between BIA and HD (ICC: 0.85, TE: 3.35 %BF, CV: 19.6%, TEM: 3.29 %BF) was lower than BB. Our modification of the BB method resulted in similar measurement consistency with the originating method. The BB method appears to represent a valid surrogate measure of %BF, superior to that observed with BIA

Integration of highly probabilistic sources into optical quantum architectures: perpetual quantum computation

In this paper we introduce a design for an optical topological cluster state computer constructed exclusively from a single quantum component. Unlike previous efforts we eliminate the need for on demand, high fidelity photon sources and detectors and replace them with the same device utilised to create photon/photon entanglement. This introduces highly probabilistic elements into the optical architecture while maintaining complete specificity of the structure and operation for a large scale computer. Photons in this system are continually recycled back into the preparation network, allowing for a arbitrarily deep 3D cluster to be prepared using a comparatively small number of photonic qubits and consequently the elimination of high frequency, deterministic photon sources.Comment: 19 pages, 13 Figs (2 Appendices with additional Figs.). Comments welcom

Discovery of a Transiting Adolescent Sub-Neptune Exoplanet with K2

The role of stellar age in the measured properties and occurrence rates of exoplanets is not well understood. This is in part due to a paucity of known young planets and the uncertainties in age-dating for most exoplanet host stars. Exoplanets with well-constrained ages, particularly those which are young, are useful as benchmarks for studies aiming to constrain the evolutionary timescales relevant for planets. Such timescales may concern orbital migration, gravitational contraction, or atmospheric photo-evaporation, among other mechanisms. Here we report the discovery of an adolescent transiting sub-Neptune from K2 photometry of the low-mass star K2-284. From multiple age indicators we estimate the age of the star to be 120 Myr, with a 68% confidence interval of 100-760 Myr. The size of K2-284 b ($R_P$ = 2.8 $\pm$ 0.1 $R_\oplus$) combined with its youth make it an intriguing case study for photo-evaporation models, which predict enhanced atmospheric mass loss during early evolutionary stages.Comment: Accepted to AJ, 36 pages, 17 figures, 5 table