When the sun never sets: diverse activity rhythms under continuous daylight in free-living arctic-breeding birds

Circadian clocks are centrally involved in the regulation of daily behavioural and physiological processes. These clocks are synchronized to the 24-hour day by external cues (Zeitgeber), the most important of which is the light-dark cycle. In polar environments, however, the strength of the Zeitgeber is greatly reduced around the summer and winter solstices (continuous daylight or continuous darkness). How animals time their behaviour under such conditions has rarely been studied in the wild. Using a radio-telemetry-based system, we investigated daily activity rhythms under continuous daylight in Barrow, Alaska, throughout the breeding season in four bird species that differ in mating system and parental behaviour. We find substantial diversity in daily activity rhythms depending on species, sex and breeding stage. Individuals exhibited either robust, entrained 24-hour activity cycles, were continuously active (arrhythmic), or showed “free-running” activity cycles. In semipalmated sandpipers, a shorebird with biparental incubation, we show that the free-running rhythm is synchronized between pair mates. The diversity of diel time-keeping under continuous daylight emphasizes the plasticity of the circadian system and the importance of the social and life-history context. Our results support the idea that circadian behaviour can be adaptively modified to enable species-specific time-keeping under polar conditions

Phase and period responses of the circadian system of mice (Mus musculus) to light stimuli of different duration

To understand entrainment of circadian systems to different photoperiods in nature, it is important to know the effects of single light pulses of different durations on the free-running system. The authors studied the phase and period responses of laboratory mice (C57BL6J//OlaHsd) to single light pulses of 7 different durations (1, 3, 4, 6, 9, 12, and 18 h) given once per 11 days in otherwise constant darkness. Light-pulse duration affected both amplitude and shape of the phase response curve. Nine-hour light pulses yielded the maximal amplitude PRC. As in other systems, the circadian period slightly lengthened following delays and shortened following advances. The authors aimed to understand how different parts of the light signal contribute to the eventual phase shift. When PRCs were plotted using the onset, midpoint, and end of the pulse as a phase reference, they corresponded best with each other when using the mid-pulse. Using a simple phase-only model, the authors explored the possibility that light affects oscillator velocity strongly in the 1st hour and at reduced strength in later hours of the pulse due to photoreceptor adaptation. They fitted models based on the 1-h PRC to the data for all light pulses. The best overall correspondence between PRCs was obtained when the effect of light during all hours after the first was reduced by a factor of 0.22 relative to the 1st hour. For the predicted PRCs, the light action centered on average at 38% of the light pulse. This is close to the reference phase yielding best correspondence at 36% of the pulses. The result is thus compatible with an initial major contribution of the onset of the light pulse followed by a reduced effect of light responsible for the differences between PRCs for different duration pulses. The authors suggest that the mid-pulse is a better phase reference than lights-on to plot and compare PRCs of different light-pulse durations

Loss of miR-200c: A Marker of Aggressiveness and Chemoresistance in Female Reproductive Cancers

We focus on unique roles of miR-200c in breast, ovarian, and endometrial cancers. Members of the miR-200 family target ZEB1, a transcription factor which represses E-cadherin and other genes involved in polarity. We demonstrate that the double negative feedback loop between miR-200c and ZEB1 is functional in some, but not all cell lines. Restoration of miR-200c to aggressive cancer cells causes a decrease in migration and invasion. These effects are independent of E-cadherin status. Additionally, we observe that restoration of miR-200c to ovarian cancer cells causes a decrease in adhesion to laminin. We have previously reported that reintroduction of miR-200c to aggressive cells that lack miR-200c expression restores sensitivity to paclitaxel. We now prove that this ability is a result of direct targeting of class III beta-tubulin (TUBB3). Introduction of a TUBB3 expression construct lacking the miR-200c target site into cells transfected with miR-200c mimic results in no change in sensitivity to paclitaxel. Lastly, we observe a decrease in proliferation in cells transfected with miR-200c mimic, and cells where ZEB1 is knocked down stably, demonstrating that the ability of miR-200c to enhance sensitivity to paclitaxel is not due to an increased proliferation rate

Compression of daily activity time in mice lacking functional Per or Cry genes

The adjustment of daily activity time (alpha) to the varying night length in nocturnal creatures was one of the functions originally attributed to a putative dual oscillator structure of circadian pacemakers in mammals. In two experimental approaches, we tested whether this ability is compromised in mice with functional deletions of one of the four circadian clock genes. First, we tested the capability of alpha compression by long days in mPer1(Brdm1) and mPer2(Brdm1) mutant mice. When exposed to a full L:D 18:6 photoperiod, wild-type and mPer1(Brdm1) mutant mice show compression followed by decompression of alpha in DD. mPer2(Brdm1) mutant mice did not compress their activity time. The interpretation of these data is, however, complicated by masking due to light. We, therefore, embarked on a second experiment, exploiting skeleton photoperiods. The skeleton photoperiod was changed stepwise from 0 to 24 h, and mCry1 and mCry2 knockout mice were now included in the design. We observed clear and systematic compression of alpha in wild-type and mCry1 and mCry2 knockout mice. mPer1(Brdm1) and mPer2(Brdm1) mice both poorly entrained to the skeleton photoperiod. The single mPer2(Brdm1) mutant mouse that did entrain did not show alpha compression. The results show that neither mCry1 nor mCry2 deletions compromise adjustment to day length, consistent with our earlier conclusions on period lengthening in constant light (Spoelstra & Daan, 2008). The mPer2(Brdm1) mutant behaves aberrantly and appears not to respond to the delaying action of light in the late subjective day. [KEYWORDS: Alpha compression circadian clock Cry1 Cry2 Per1 Per2 Mus musculus photoperiod MAMMALIAN CIRCADIAN CLOCK SUPRACHIASMATIC NUCLEUS NOCTURNAL RODENTS CONSTANT LIGHT MUTANT MICE IN-VITRO DROSOPHILA EXPRESSION PACEMAKERS MPER2 Biology Physiology

Isotopic Production Cross Sections in Proton-Nucleus Collisions at 200 MeV

Intermediate mass fragments (IMF) from the interaction of $^{27}$Al, $^{59}$Co and $^{197}$Au with 200 MeV protons were measured in an angular range from 20 degree to 120 degree in the laboratory system. The fragments, ranging from isotopes of helium up to isotopes of carbon, were isotopically resolved. Double differential cross sections, energy differential cross sections and total cross sections were extracted.Comment: accepted by Phys. Rev.

Probing the Magnetized Interstellar Medium Surrounding the Planetary Nebula Sh 2-216

We present 1420 MHz polarization images of a 2.5 X 2.5 degree region around the planetary nebula (PN) Sh 2-216. The images are taken from the Canadian Galactic Plane Survey (CGPS). An arc of low polarized intensity appears prominently in the north-east portion of the visible disk of Sh 2-216, coincident with the optically identified interaction region between the PN and the interstellar medium (ISM). The arc contains structural variations down to the ~1 arcminute resolution limit in both polarized intensity and polarization angle. Several polarization-angle "knots" appear along the arc. By comparison of the polarization angles at the centers of the knots and the mean polarization angle outside Sh 2-216, we estimate the rotation measure (RM) through the knots to be -43 +/- 10 rad/m^2. Using this estimate for the RM and an estimate of the electron density in the shell of Sh 2-216, we derive a line-of-sight magnetic field in the interaction region of 5.0 +/- 2.0 microG. We believe it more likely the observed magnetic field is interstellar than stellar, though we cannot completely dismiss the latter possibility. We interpret our observations via a simple model which describes the ISM magnetic field around Sh 2-216, and comment on the potential use of old PNe as probes of the magnetized ISM.Comment: 25 pages, 4 figures. Accepted for publication in the Astrophysical Journa

Artificial light at night affects plant–herbivore interactions

Artificial light at night (ALAN) affects species' physiology and behaviour, and the interactions between species. Despite the importance of plants as primary producers, it remains poorly understood whether and how effects of ALAN on plants cascade through the food web. 2. We assess the extent to which ALAN of different spectra result in plant-mediated insect herbivory damage. In a 6-month field experiment, we exposed plants of differing palatability to three colours of ALAN and a dark control, and assessed plant traits (growth rate, leaf size, foliar density and thickness) and insect herbivory (represented by insect damage as loss of foliage to leaf-chewing insects, and gall abundance by phloem-feeding herbivory). 3. We found evidence for plant trait-mediated ALAN effects on herbivory for oak, but not for blueberry. In oak, ALAN of different colours changed the direction of relationships of insect damage with relative growth rate and with leaf thickness. Moreover, we found that the effects of ALAN on herbivory damage differed markedly between forest types within the same locale, particularly in the red light treatment. 4. Synthesis and applications. Our results provide evidence that continuous nighttime light, as provided by street lighting around the world, affects food web interactions. The nature of these effects differed by species and appeared to depend on forest type and the light spectrum employed, thus underlining the context dependency of ALAN in different ecosystems and environmental settings. These findings highlight the complexity of using spectral manipulation as a mitigation measure, and the need for further consideration of ALAN in environmental management and planning, to limit the exposure and impact of cascading effects of artificial light at night on food webs and communities.Environmental Biolog

A Randomized Controlled Trial of the Feasibility and Preliminary Efficacy of a Texting Intervention on Medication Adherence in Adults Prescribed Oral Anti-Cancer Agents: Study Protocol

Aim: The aim of this study was to report a study protocol that examines feasibility, preliminary efficacy and satisfaction of a text message intervention on the outcome of medication adherence in adult patients prescribed oral anti-cancer agents. Background: Administration of oral anti-cancer agents occurs in the home setting, requiring patients to self-manage the regimen as prescribed. However, many barriers to medication adherence exist: regimens are often complex, with cycling of two or more medications; side effects of treatment; most cancer patients are older with comorbid conditions and competing demands; and cognitive decline and forgetfulness may occur. Research indicates patients miss nearly one-third of the prescribed oral anti-cancer agent dosages. Text message interventions have been shown to improve medication adherence in chronic conditions other than cancer. However, a majority of those patients were less than 50 years of age and most cancer patients are diagnosed later in life. Design: A two-group randomized controlled trial with repeated measures. Methods: Seventy-five adult patients newly prescribed an oral anti-cancer agent will be recruited (project funded in April 2013) from community cancer centres and a specialty pharmacy. Participants will be randomized to either a control group (n = 25; usual care) or an intervention group (n = 50; usual care plus text messages timed to medication regimen). Outcome measures include: medication adherence, feasibility and satisfaction with the intervention. Data will be collected over 8 weeks: baseline, weekly and exit. Discussion: Standardized text message intervention protocol and detailed study procedures have been developed in this study to improve medication adherence

Proof of Concept of a Mobile Health Short Message Service Text Message Intervention That Promotes Adherence to Oral Anticancer Agent Medications: A Randomized Controlled Trial

Introduction: This multisite, randomized controlled trial assigned 75 adult cancer patients prescribed an oral anticancer agent to either an experimental group that received daily text messages for adherence for 21 days plus usual care or a control group that received usual care. Materials and Methods: Measures were administered at baseline, weekly (Weeks 1–8), and at exit (Week 9). A satisfaction survey was conducted following the intervention. Acceptability, feasibility, and satisfaction were examined. Primary outcomes were adherence and symptoms. Secondary outcomes were depressive symptoms, self-efficacy, cognition, physical function, and social support. Mixed or general linear models were used for the analyses comparing trial groups. Effect sizes (ES) were estimated to gauge clinical significance. Results: Regarding acceptability, 57.2% (83 of 145) of eligible patients consented, 88% (n = 37 of 42) receiving text messages read them most or all of the time, and 90% (n  = 38) were satisfied. The differences between experimental and control groups\u27 ES were 0.29 for adherence, 0.21 for symptom severity, and 0.21 for symptom interference, and differences were not statistically significant. Furthermore, perceived social support was higher (p = 0.04; ES = 0.54) in the experimental group. Conclusions: Proof of concept and preliminary efficacy of a mobile health intervention using text messages to promote adherence for patients prescribed oral anticancer agents were demonstrated. Patients accepted and had high satisfaction with the intervention, and adherence improved after the intervention. Text messages show promise. Additional research is needed prior to use in practice