Island Distance in One-Dimensional Epitaxial Growth

The typical island distance $\ell$ in submonlayer epitaxial growth depends on the growth conditions via an exponent $\gamma$. This exponent is known to depend on the substrate dimensionality, the dimension of the islands, and the size $i^*$ of the critical nucleus for island formation. In this paper we study the dependence of $\gamma$ on $i^*$ in one--dimensional epitaxial growth. We derive that $\gamma = i^*/(2i^* + 3)$ for $i^*\geq 2$ and confirm this result by computer simulations.Comment: 5 pages, 3 figures, uses revtex, psfig, 'Note added in proof' appende

Comment on "Test of constancy of speed of light with rotating cryogenic optical resonators"

A recent experiment by Antonini et. al. [Phys. Rev. A {\bf 71}, 050101R 2005], set new limits on Lorentz violating parameters in the frame-work of the photon sector of the Standard Model Extension (SME), $\tilde{\kappa}_{e-}^{ZZ}$, and the Robertson-Mansouri-Sexl (RMS) framework, $\beta-\delta-1/2$. The experiment had significant systematic effects caused by the rotation of the apparatus which were only partly analysed and taken into account. We show that this is insufficient to put a bound on $\tilde{\kappa}_{e-}^{ZZ}$ and the bound on $\beta-\delta-1/2$ represents a five-fold improvement not a ten-fold improvement as claimed. (For reply see Phys. Rev. A 72, 066102 (2005) DOI: 10.1103/PhysRevA.72.066102)Comment: 2 page

Finger extensor variability in TMS parameters among chronic stroke patients

BACKGROUND: This study determined the reliability of topographic motor cortical maps and MEP characteristics in the extensor digitorum communis (EDC) evoked by single-pulse TMS among patients with chronic stroke. METHODS: Each of ten patients was studied on three occasions. Measures included location of the EDC hotspot and center of gravity (COG), threshold of activation and average amplitude of the hotspot, number of active sites, map volume, and recruitment curve (RC) slope. RESULTS: Consistent intrahemispheric measurements were obtained for the three TMS mapping sessions for all measured variables. No statistically significant difference was observed between hemispheres for the number of active sites, COG distance or the RC slope. The magnitude and range of COG movement between sessions were similar to those reported previously with this muscle in able-bodied individuals. The average COG movement over three sessions in both hemispheres was 0.90 cm. The average COG movement in the affected hemisphere was 1.13 (± 0.08) cm, and 0.68 (± 0.04) cm) for the less affected hemisphere. However, significant interhemispheric variability was seen for the average MEP amplitude, normalized map volume, and resting motor threshold. CONCLUSION: The physiologic variability in some TMS measurements of EDC suggest that interpretation of TMS mapping data derived from hemiparetic patients in the chronic stage following stroke should be undertaken cautiously. Irrespective of the muscle, potential causes of variability should be resolved to accurately assess the impact of pharmacological or physical interventions on cortical organization as measured by TMS among patients with stroke

Regurgitative food transfer among wild wolves

Few studies of monogamous canids have addressed regurgitation in the context of extended parental care and alloparental care within family groups. We studied food transfer by regurgitation in a pack of wolves on Ellesmere Island, North West Territories, Canada, during 6 summers from 1988 through 1996. All adult wolves, including yearlings and a post-reproductive female, regurgitated food. Although individuals regurgitated up to five times per bout, the overall ratio of regurgitations per bout was 1.5. Pups were more likely to receive regurgitations (81%) than the breeding female (14%) or auxiliaries (6%). The breeding male regurgitated mostly to the breeding female and pups, and the breeding female regurgitated primarily to pups. The relative effort of the breeding female was correlated with litter size (Kendall’s τ = 0.93, P = 0.01). Peu d’études ont abordé la question de la régurgitation en relation avec les soins parentaux et alloparentaux au sein des familles chez les canidés monogames. Nous avons étudié le transfert de la nourriture par régurgitation au sein d’une meute de loups de l’île d’Ellesmere, Territoires du Nord-Ouest, Canada, durant six étés, de 1988 à la fin de 1996. Tous les loups adultes, y compris les jeunes de 1 an et les femelles post-parturientes, régurgitaient de la nourriture. Certains individus régurgitaient jusqu’à 5 fois par épisode, mais, dans l’ensemble, le nombre de régurgitations par épisode était de 1,5. Les petits étaient plus susceptibles de recevoir des régurgitations (81%) que les femelles reproductrices (14%) ou les auxiliaires (6%). Les mâles reproducteurs régurgitaient à leur partenaire et à leurs petits et les femelles reproductrices régurgitaient surtout à leurs petits. L’effort relatif des femelles était en corrélation avec le nombre de petits dans leur portée (τ de Kendall = 0,93, P = 0,01)

Home-based reach-to-grasp training for people after stroke: study protocol for a feasibility randomized controlled trial

BackgroundThis feasibility study is intended to assess the acceptability of home-based task-specific reach-to-grasp (RTG) training for people with stroke, and to gather data to inform recruitment, retention, and sample size for a definitive randomized controlled trial. Methods/designThis is to be a randomized controlled feasibility trial recruiting 50 individuals with upper-limb motor impairment after stroke. Participants will be recruited after discharge from hospital and up to 12 months post-stroke from hospital stroke services and community therapy-provider services. Participants will be assessed at baseline, and then electronically randomized and allocated to group by minimization, based on the time post-stroke and extent of upper-limb impairment. The intervention group will receive 14 training sessions, each 1 hour long, with a physiotherapist over 6 weeks and will be encouraged to practice independently for 1 hour/day to give a total of 56 hours of training time per participant. Participants allocated to the control group will receive arm therapy in accordance with usual care. Participants will be measured at 7 weeks post-randomization, and followed-up at 3 and 6 months post-randomization. Primary outcome measures for assessment of arm function are the Action Research Arm Test (ARAT) and Wolf Motor Function Test (WMFT). Secondary measures are the Motor Activity Log, Stroke Impact Scale, Carer Strain Index, and health and social care resource use. All assessments will be conducted by a trained assessor blinded to treatment allocation. Recruitment, adherence, withdrawals, adverse events (AEs), and completeness of data will be recorded and reported. DiscussionThis study will determine the acceptability of the intervention, the characteristics of the population recruited, recruitment and retention rates, descriptive statistics of outcomes, and incidence of AEs. It will provide the information needed for planning a definitive trial to test home-based RTG training. Trial registrationISRCTN: ISRCTN5671658

High Frequency of Extra-Pair Paternity in Eastern Kingbirds

Genetic parentage in the socially monogamous and territorial Eastern Kingbird( Tyrannust tyrannus) was examined in a central New York population by multilocus DNA fingerprinting. Extra-pair young were identified in 60% (12 of 20) of nests. Of the 64 nestlings profiled, 42% were sired by extra-pair males, but no cases of conspecific brood parasitism were detected. These results are markedly different from a previous electrophoretic study of the same species in a Michigan population, which reported 39% of nestlings were unrelated to one (typically the mother, quasiparasitismo)r both (conspecificb roodp arasitism) of the putative parents. In the New York population, extra-pairp aternityw as most common among females that returned to breed on a former territory. Among females that were new to a breeding territory, extrapair paternity increased directly with breeding density. Although the power of the tests was low, neither breeding synchrony nor male experience with a breeding territory appeared to be associated with the occurrence of extra-pair young

Improved test of Lorentz Invariance in Electrodynamics using Rotating Cryogenic Sapphire Oscillators

We present new results from our test of Lorentz invariance, which compares two orthogonal cryogenic sapphire microwave oscillators rotating in the lab. We have now acquired over 1 year of data, allowing us to avoid the short data set approximation (less than 1 year) that assumes no cancelation occurs between the $\tilde{\kappa}_{e-}$ and $\tilde{\kappa}_{o+}$ parameters from the photon sector of the standard model extension. Thus, we are able to place independent limits on all eight $\tilde{\kappa}_{e-}$ and $\tilde{\kappa}_{o+}$ parameters. Our results represents up to a factor of 10 improvement over previous non rotating measurements (which independently constrained 7 parameters), and is a slight improvement (except for $\tilde{\kappa}_{e-}^{ZZ}$) over results from previous rotating experiments that assumed the short data set approximation. Also, an analysis in the Robertson-Mansouri-Sexl framework allows us to place a new limit on the isotropy parameter $P_{MM}=\delta-\beta+{1/2}$ of $9.4(8.1)\times10^{-11}$, an improvement of a factor of 2.Comment: Accepted for publication in Phys. Rev.

Factors to Consider in Improving Prescription Drug Pharmacy Leaflets

Today, when consumers receive prescription drug pharmacy leaflets (also known as ‘consumer medication information’ or CMI), they often appear in small font size, with cluttered layouts, and distracting information. This problem has attracted the attention of the U.S. Food and Drug Administration in advocating for more comprehendible, accurate, and easy-to-access CMI formats. Our study of four different CMI prototypes shows that an expanded Over-the-Counter (OTC) Drug Facts prototype is the best for improving comprehension accuracy, and is especially effective for those with lower health literacy and health motivation. A simpler OTC prototype did not aid accuracy scores due in part to its lack of complexity; whereas the most complex prototype (the revised medication guide – similar to most CMI today) reduced leaflet likability and usage intentions. Finally, continued leaflet availability improved accuracy scores for lower health literacy and health motivation respondents. Implications for marketing and public health policy are offered

Subtoxic Alterations in Hepatocyte-Derived Exosomes: An Early Step in Drug-Induced Liver Injury?

Drug-induced liver injury (DILI) is a significant clinical and economic problem in the United States, yet the mechanisms that underlie DILI remain poorly understood. Recent evidence suggests that signaling molecules released by stressed hepatocytes can trigger immune responses that may be common across DILI mechanisms. Extracellular vesicles released by hepatocytes, principally hepatocyte-derived exosomes (HDEs), may constitute one such signal. To examine HDE alterations as a function of drug-induced stress, this work utilized prototypical hepatotoxicant acetaminophen (APAP) in male Sprague-Dawley (SD) rats, SD rat hepatocytes, and primary human hepatocytes. HDE were isolated using ExoQuick precipitation reagent and analyzed by quantification of the liver-specific RNAs albumin and microRNA-122 (miR-122). In vivo, significant elevations in circulating exosomal albumin mRNA were observed at subtoxic APAP exposures. Significant increases in exosomal albumin mRNA were also observed in primary rat hepatocytes at subtoxic APAP concentrations. In primary human hepatocytes, APAP elicited increases in both exosomal albumin mRNA and exosomal miR-122 without overt cytotoxicity. However, the number of HDE produced in vitro in response to APAP did not increase with exosomal RNA quantity. We conclude that significant drug-induced alterations in the liver-specific RNA content of HDE occur at subtoxic APAP exposures in vivo and in vitro, and that these changes appear to reflect selective packaging rather than changes in exosome number. The current findings demonstrate that translationally relevant HDE alterations occur in the absence of overt hepatocellular toxicity, and support the hypothesis that HDE released by stressed hepatocytes may mediate early immune responses in DILI