Daily Cycling Research Articles

Improved flexibility and economics of Calcium Looping power plants by thermochemical energy storage

In this work, a Calcium looping (CaL) system including high temperature sorbent storage is presented, allowing to reduce the size of the calciner and the associated capital-intensive equipment (ASU and CPU). Reduction of the capital costs is particularly important for power plants with low capacity factors, which is becoming increasingly frequent for fossil fuel power plants in electric energy mixes with increasing share of intermittent renewables. The process assessment is performed by: (i) defining pulverized coal power plant (PCPP) with CaL capture system with and without sorbent storage and their mass and energy balances at nominal load; (ii) defining a simple method to predict the performance of the plant at part-load; (iii) defining the economic model, including functions for the estimation of the plant equipment cost; (iv) performing yearly simulations of the systems to calculate yearly electricity production, CO2 emissions and levelized cost of electricity for different sizes of the calcination line and the storage system and (v) performing sensitivity analysis with different power production plans and carbon taxes. With this process, optimal size of the calciner and of the storage system minimizing the cost of electricity have been found.The optimal plant design was found to correspond to a solids storage system sized to manage the weekly cycling and a calciner line sized on the average weekly load. However, to avoid excessively large solids storage system, sizing the calciner on the average daily load and the storage system to manage the daily cycling appears more feasible from the logistic viewpoint and leads to minor economic penalty compared with the optimal plant design. For the selected case sized on the daily cycling, reduction of the cost of CO2 avoided between 16% and 26% have been obtained compared to the reference CaL plant without solids storage, for representative medium and low capacity factor scenarios respectively.

Evaluation of Different Dentifrice Compositions for Increasing the Hardness of Demineralized Enamel: An in Vitro Study.

This study aimed to evaluate microhardness of a dentifrice containing fluoride and arginine compared to a positive control (fluoride only) and a negative control (no fluoride) on sound and demineralized bovine enamel surfaces. Specimens were randomly assigned to different treatments that included daily pH cycling and brushing three times a day with one of the following dentifrices (n = 8): Neutraçucar (arginine and fluoride), Colgate Total 12 (fluoride) and My First Colgate (no fluoride). Enamel carious lesions were artificially created one week before the beginning of these treatments (demineralized bovine enamel (DE) groups). The same groups were also tested in sound enamel (sound bovine enamel (SE) groups). Microhardness was measured at baseline and after one, two, and five weeks of treatment using a Knoop indenter. Statistical analysis involved two-way Analysis of Variance (ANOVA) and Tukey’s test. After five weeks, both Total 12 and Neutraçucar had increased the microhardness of DE specimens (p < 0.05). Only Neutraçucar had increased the microhardness of the sound enamel after five weeks of treatment. Thus, it could be concluded that arginine-based dentifrices increase the microhardness of sound and demineralized bovine enamel surfaces.

CK1α Collaborates with DOUBLETIME to Regulate PERIOD Function in the Drosophila Circadian Clock.

The animal circadian timing system interprets environmental time cues and internal metabolic status to orchestrate circadian rhythms of physiology, allowing animals to perform necessary tasks in a time-of-day-dependent manner. Normal progression of circadian rhythms is dependent on the daily cycling of core transcriptional factors that make up cell-autonomous molecular oscillators. In Drosophila, PERIOD (PER), TIMELESS (TIM), CLOCK (CLK), and CYCLE (CYC) are core clock proteins that function in a transcriptional-translational feedback mechanism to regulate the circadian transcriptome. Posttranslational modifications of core clock proteins provide precise temporal control over when they are active as regulators of clock-controlled genes. In particular, phosphorylation is a key regulatory mechanism that dictates the subcellular localization, stability, and transcriptional activity of clock proteins. Previously, casein kinase 1α (CK1α) has been identified as a kinase that phosphorylates mammalian PER1 and modulates its stability, but the mechanisms by which it modulates PER protein stability is still unclear. Using Drosophila as a model, we show that CK1α has an overall function of speeding up PER metabolism and is required to maintain the 24 h period of circadian rhythms. Our results indicate that CK1α collaborates with the key clock kinase DOUBLETIME (DBT) in both the cytoplasm and the nucleus to regulate the timing of PER-dependent repression of the circadian transcriptome. Specifically, we observe that CK1α promotes PER nuclear localization by antagonizing the activity of DBT to inhibit PER nuclear translocation. Furthermore, CK1α enhances DBT-dependent PER phosphorylation and degradation once PER moves into the nucleus.SIGNIFICANCE STATEMENT Circadian clocks are endogenous timers that integrate environmental signals to impose temporal control over organismal physiology over the 24 h day/night cycle. To maintain the 24 h period length of circadian clocks and to ensure that circadian rhythms are in synchrony with the external environment, key proteins that make up the molecular oscillator are extensively regulated by phosphorylation to ensure that they perform proper time-of-day-specific functions. Casein kinase 1α (CK1α) has previously been identified as a kinase that phosphorylates mammalian PERIOD (PER) proteins to promote their degradation, but the mechanism by which it modulates PER stability is unclear. In this study, we characterize the mechanisms by which CK1α interacts with DOUBLETIME (DBT) to achieve the overall function of speeding up PER metabolism and to ensure proper time-keeping.

Development of a New High-Strength Steel for Low Pressure Steam Turbine End-Stage Blades

Influenced by the growing share of Renewable Energies, higher flexibility and increased efficiency of fossil power plants as well as improved cost efficiency in production of turbine components are evident market trends. Daily cycling in turbine operations leads to advanced requirements for robust design especially of rotating parts. Low pressure (LP) steam turbine end-stage blades with larger exhaust areas are one lever to increase the efficiency of the turbine by reduction of exhaust losses and also to realize cost-efficient single flow exhaust applications. Consequently, blade steels with improved mechanical properties are required. The results of the development of a new high-strength precipitation-hardening (PH) steel for LP end-stage blade application with significantly enhanced material properties are reported. The paper covers the testing strategy applied and information on crucial material parameters like improved low cycle and high cycle fatigue (HCF) behavior while keeping good stress corrosion cracking (SCC) resistance and corrosion fatigue (CF) properties. Furthermore, first manufacturing experiences and validation results from a full-scale component test rig are presented.

The role of the natural and built environment in cycling duration in the Netherlands

BackgroundCycling for transportation has the potential to contribute to an increase in people’s physical activity levels. A growing body of evidence links the natural and the built environment to cycling. Whereas previous studies were mostly done within one city or one region, the present study covers the whole of the Netherlands, allowing an investigation of whether associations between environmental characteristics and cycling are context-specific. The study examines the extent to which objectively measured natural and built environment characteristics contribute to cycling duration in the Netherlands, as well as the differential effect of environmental characteristics on cycling duration by municipality size.MethodsOur sample from the Dutch National Travel Survey 2010–2014 comprised 110,027 people aged 20–89 years, residing in 3163 four-digit postal code areas, nested within 387 municipalities across the whole of the Netherlands. Multilevel Tobit regression models were fitted to assess the associations between the natural and the built environment with average daily cycling duration (in minutes), while adjusting for individual and household characteristics. Interaction effects of natural and built environment characteristics and municipality size on cycling duration were also investigated.ResultsHigher address density, more bus stops, and shorter distance from home to the nearest train station were positively related to cycling duration. Respondents were more likely to cycle on days with higher temperatures, less wind, and less precipitation. Interaction tests showed that increased street density and address density were less cycling-promotive in small urban areas compared to medium or large cities. On the other hand, the positive association between number of bus stops and cycling duration was weaker in the largest and medium-sized cities compared to small urban and rural areas.ConclusionsInteractions suggest that relations between environmental characteristics and cycling duration are context-specific (i.e., dependent on circumstances that differ between highly urbanized and less urbanized areas). Our findings need to be replicated in other countries to gain more insight into the interplay between environmental factors and municipality size.

The association of bicycle-related genital numbness and Sexual Health Inventory for Men (SHIM) score: results from a large, multinational, cross-sectional study.

To assess the association of genital numbness and erectile dysfunction in male cyclists. Cyclists were recruited through Facebook advertisements and outreach to sporting clubs. This is a secondary analysis of a larger epidemiological population-based study that examined sexual and urinary wellness in athletes. We queried cycling habits and erectile function using Sexual Health Inventory for Men (SHIM). A total of 2774 male cyclists were included in the analysis. Amongst cyclists, there was a statistically significant increase in the trend of genital numbness presence with more years of cycling (P = 0.002), more frequent weekly cycling (P < 0.001), and longer cycling distance at each ride (P < 0.001). Less frequent use of padded shorts (odds ratio [OR] 0.14, P < 0.001) and lower handlebar (OR 0.49, P < 0.001) were associated with numbness, but body mass index (BMI) (OR 1.1, P = 0.33) and age (OR 1.2, P = 0.15) were not. In a multivariate logistic regression model, after adjusting for age, BMI, and lifetime miles (calculated by average daily cycling mileage × cycling days/week × cycling years.), there were no statistically significant differences in mean SHIM score between cyclists with and cyclists without numbness (20.3 vs 20.2, P = 0.83). However, interestingly, the subset of cyclists who reported numbness in the buttock reported statistically significantly worse SHIM scores (20.3 vs 18.4, P < 0.001). This association was not present in cyclists who reported numbness in the scrotum, penis, or perineum and remained significant after adjusting for overall biking intensity. Cyclists report genital numbness in proportion with biking intensity but numbness is not associated with worse sexual function in this cohort.

2282 - Area Variations in People's Cycling Duration in the Netherlands: The Role of the Natural and the Built Environment

Highest Scoring Abstract: Doctoral Background Cycling for transportation has the potential to contribute to an increase in people's physical activity levels. A growing body of evidence links the natural and the built environment to cycling. Whereas previous studies were mostly done within one city or one region, the present study covered the whole of the Netherlands, giving the opportunity to investigate whether associations between environmental characteristics and cycling are context-specific. The study examined the extent to which objectively measured natural and built environment characteristics contribute to differences in cycling between 4-digit postal code areas (“PC4 areas”) and between municipalities in the Netherlands, as well as the differential effect of environmental characteristics on cycling by municipality size. Methods Our sample from the Dutch National Travel Survey 2010–2014 comprised 110,027 people aged 20–89 years, residing in 3,163 PC4 areas, nested within 387 municipalities. Multilevel Tobit regression models were fitted to assess the associations between the natural and the built environment with average daily cycling duration (in minutes), while adjusting for individual and household characteristics. Interaction effects of natural and built environment characteristics and municipality size on cycling duration were also investigated. Results After adjustment for individual and household characteristics, 3.4% of the variance on cycling duration could be explained by environmental factors. Higher address density, more bus stops, and shorter distance from home to the nearest train station were positively related to cycling duration. Respondents were more likely to cycle on days with higher temperatures, less wind, and less precipitation. Interaction tests showed that increased street density and address density appeared to be less cycling-promotive in small urban areas compared to medium or large cities. On the other hand, the positive associate between number of bus stops and cycling duration was weaker in the four largest cities and medium-sized cities compared to small urban and rural areas. Conclusions Higher address density, more bus stops, and shorter distance from home to nearest train station were positively related to cycling duration. Interactions suggest that relations between environmental characteristics and cycling duration are context-specific (e.g. dependent on circumstances that differ between highly urbanized and less urbanized areas). The findings confirm that the emphasis in Dutch policies on compact, development and good public transport has helped achieve a high level of cycling at both the city and the national level.

MP84-08 NEW INSIGHT INTO THE ASSOCIATION OF BICYCLE RELATED GENITAL NUMBNESS AND SEXUAL FUNCTION: RESULTS FROM A LARGE, MULTINATIONAL, CROSS-SECTIONAL STUDY

You have accessJournal of UrologySexual Function/Dysfunction: Penis/Testis/Urethra: Benign Disease & Malignant Disease II1 Apr 2018MP84-08 NEW INSIGHT INTO THE ASSOCIATION OF BICYCLE RELATED GENITAL NUMBNESS AND SEXUAL FUNCTION: RESULTS FROM A LARGE, MULTINATIONAL, CROSS-SECTIONAL STUDY Nima Baradaran, Mohannad Awad, Thomas Gaither, Kirkpatrick Fergus, Aron Liaw, Tom Sanford, Michael Eisenberg, and Benjamin Breyer Nima BaradaranNima Baradaran More articles by this author , Mohannad AwadMohannad Awad More articles by this author , Thomas GaitherThomas Gaither More articles by this author , Kirkpatrick FergusKirkpatrick Fergus More articles by this author , Aron LiawAron Liaw More articles by this author , Tom SanfordTom Sanford More articles by this author , Michael EisenbergMichael Eisenberg More articles by this author , and Benjamin BreyerBenjamin Breyer More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.2776AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Prolonged time in the saddle is associated with decreased penile and perineal blood flow and temporary genital numbness (GN). The impact of numbness on future sexual function is unclear. We aim to assess the association of GN and sexual dysfunction in cyclists. METHODS Cyclists were recruited through Facebook advertisements and outreach to sporting clubs. This is a secondary analysis of a larger epidemiologic population based study that examined sexual and urinary wellness in athletes. We queried cycling habits and erectile function using Sexual Health Inventory for Men (SHIM). RESULTS The demographic and cycling habits of 2,774 male cyclists are summarized in table 1. Among cyclists, there was a statistically significant increase in trend of GN with more years of biking (p=0.002), more frequent weekly biking (p<0.001), and longer biking distance at each ride (p<0.001). Less frequent use of padded shorts (OR 0.14, p<0.001), lower handlebar (OR 0.49, p<0.001) were associated with GN but BMI (OR 1.1, p=0.33) and age (OR 1.2, p=0.15) were not. In a multivariate logistic regression model, after adjusting for age, BMI, and lifetime miles (calculated by average daily cycling mileage x cycling days/week x cycling years.), there were no statistically significant differences in mean SHIM score between cyclists with and cyclists without GN (20.3 vs. 20.2, p=0.83). Interestingly however, the subset of cyclists who reported GN in the buttock reported statistically significantly worse SHIM (20.3 vs. 18.4, p<0.001). This association was not present in cyclists with GN in the scrotum, penis, or perineum and remained significant after adjusting for overall biking intensity. CONCLUSIONS Cyclists report GN in proportion with biking intensity but GN is not associated with worse sexual function in this cohort. © 2018FiguresReferencesRelatedDetails Volume 199Issue 4SApril 2018Page: e1127-e1128 Advertisement Copyright & Permissions© 2018MetricsAuthor Information Nima Baradaran More articles by this author Mohannad Awad More articles by this author Thomas Gaither More articles by this author Kirkpatrick Fergus More articles by this author Aron Liaw More articles by this author Tom Sanford More articles by this author Michael Eisenberg More articles by this author Benjamin Breyer More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Daily transcription cycling in the baboon

Circadian Rhythms Much of our knowledge about the important effects of circadian rhythms in physiology comes from studies of mice, which are nocturnal. Mure et al. report transcriptional profiles from many tissues and brain regions in baboons over a 24-hour period (see the Perspective by Millius and

A Laboratory Curse: Variation in Temperature Stimulates Embryonic Development and Shortens Diapause.

An ongoing biological debate concerns the difference in trait expression in continuous versus cycling temperature regimes, but are even daily cycling temperatures sufficient to generate natural expression of traits? We compared embryonic development and the duration of diapause for Mormon cricket Anabrus simplex Haldeman (Orthoptera: Tettigoniidae) eggs incubated in a daily cycling temperature constant in both amplitude and thermoperiod with those in a cycling temperature that was patterned after natural fluctuations in ambient temperature. Although the proportion of eggs developing did not differ between treatments, 128 d of vernalization was required to hatch after incubation in the constant cycling treatment relative to 42 d in the more variable cycle. We then compared these same development and diapause traits for eggs incubated in a daily cycling temperature that was constant in amplitude but varied in thermoperiod with those in the cycling temperature patterned after natural fluctuations in ambient temperature. The proportion of eggs developing in this constant cycling treatment was nearly half that in the variable treatment, and 128 d was insufficient time to break diapause following the constant cycling treatment even though the thermoperiods were now more similar. We have found that variation in the cycling temperature to mimic natural fluctuations in amplitude and period broadens the time when eggs can be warmed up for hatching and improves hatching success. Daily cycling temperatures that are constant over the season are insufficient to generate natural trait expression.

Diurnal transcriptome atlas of a primate across major neural and peripheral tissues.

Diurnal gene expression patterns underlie time-of-the-day-specific functional specialization of tissues. However, available circadian gene expression atlases of a few organs are largely from nocturnal vertebrates. We report the diurnal transcriptome of 64 tissues, including 22 brain regions, sampled every 2 hours over 24 hours, from the primate Papio anubis (baboon). Genomic transcription was highly rhythmic, with up to 81.7% of protein-coding genes showing daily rhythms in expression. In addition to tissue-specific gene expression, the rhythmic transcriptome imparts another layer of functional specialization. Most ubiquitously expressed genes that participate in essential cellular functions exhibit rhythmic expression in a tissue-specific manner. The peak phases of rhythmic gene expression clustered around dawn and dusk, with a "quiescent period" during early night. Our findings also unveil a different temporal organization of central and peripheral tissues between diurnal and nocturnal animals.

Ontogeny of Circadian Rhythms and Synchrony in the Suprachiasmatic Nucleus.

In mammals, the suprachiasmatic nucleus (SCN) of the hypothalamus coordinates daily rhythms including sleep-wake, hormone release, and gene expression. The cells of the SCN must synchronize to each other to drive these circadian rhythms in the rest of the body. The ontogeny of circadian cycling and intercellular coupling in the SCN remains poorly understood. Recent in vitro studies have recorded circadian rhythms from the whole embryonic SCN. Here, we tracked the onset and precision of rhythms in PERIOD2 (PER2), a clock protein, within the SCN isolated from embryonic and postnatal mice of undetermined sex. We found that a few SCN cells developed circadian periodicity in PER2 by 14.5 d after mating (E14.5) with no evidence for daily cycling on E13.5. On E15.5, the fraction of competent oscillators increased dramatically corresponding with stabilization of their circadian periods. The cells of the SCN harvested at E15.5 expressed sustained, synchronous daily rhythms. By postnatal day 2 (P2), SCN oscillators displayed the daily, dorsal-ventral phase wave in clock gene expression typical of the adult SCN. Strikingly, vasoactive intestinal polypeptide (VIP), a neuropeptide critical for synchrony in the adult SCN, and its receptor, VPAC2R, reached detectable levels after birth and after the onset of circadian synchrony. Antagonists of GABA or VIP signaling or action potentials did not disrupt circadian synchrony in the E15.5 SCN. We conclude that endogenous daily rhythms in the fetal SCN begin with few noisy oscillators on E14.5, followed by widespread oscillations that rapidly synchronize on E15.5 by an unknown mechanism.SIGNIFICANCE STATEMENT We recorded the onset of PER2 circadian oscillations during embryonic development in the mouse SCN. When isolated at E13.5, the anlagen of the SCN expresses high, arrhythmic PER2. In contrast, a few cells show noisy circadian rhythms in the isolated E14.5 SCN and most show reliable, self-sustained, synchronized rhythms in the E15.5 SCN. Strikingly, this synchrony at E15.5 appears before expression of VIP or its receptor and persists in the presence of blockers of VIP, GABA or neuronal firing. Finally, the dorsal-ventral phase wave of PER2 typical of the adult SCN appears ∼P2, indicating that multiple signals may mediate circadian synchrony during the ontogeny of the SCN.

“Stiction Syndrome”: Non-Operative Management of Patients With Difficult AMS 700 Series Inflation

IntroductionStatic friction (stiction) is a mechanical phenomenon in which a state of increased resistance exists across a control valve mechanism. AimTo present a strategy for non-operative management of inflatable penile prosthesis (IPP) cases with pump malfunction from pump valve stiction. MethodsAll patients had American Medical Systems (AMS; Minnetonka, MN, USA) 700 series Momentary Squeeze IPPs with transient pump malfunction owing to pump valve stiction after extended periods of device inactivity. Main Outcome MeasuresOur evolving non-operative management experience with the “forced deflation” maneuver is described. This technique has successfully prevented the need for surgical pump replacement. Of patients with IPP who were instructed to inflate and deflate daily to prevent stiction recurrence, none have re-presented with difficult inflation. ResultsOf 306 patients receiving the AMS 700 series IPP at our institution from 2007 through 2015, 6 (1.9%) presented with difficulty activating the Momentary Squeeze pump (from 2011 through 2015). Four additional patients were referred from outside institutions with the same complaint. All patients (10 of 10, 100%) presented after a prolonged period of inactivity (minimum = 6 weeks) during which the IPP was not cycled and remained stagnant. Although the initial four patients (40%) underwent surgical exploration with pump mobilization and replacement, the six most recent patients (60%) were successfully instructed in the forced deflation maneuver in the office, which enabled the device to cycle normally thereafter. ConclusionDevice inactivity, for as little as 6 weeks, can predispose to Momentary Squeeze pump valve malfunction; and a regimen of daily IPP cycling could prevent stiction-related malfunction. Our findings should encourage practitioners to attempt conservative management of patients with “stiction syndrome” whenever possible, thereby avoiding unnecessary surgery.Kavoussi NL, Viers BR, VanDyke ME, et al. “Stiction Syndrome”: Non-Operative Management of Patients With Difficult AMS 700 Series Inflation. J Sex Med 2017;14:1079–1083.

To be or not to be rhythmic? A review of studies on organisms inhabiting constant environments

Circadian clocks are endogenous time keeping mechanisms that drive near 24-h behavioural, physiological and metabolic rhythms in organisms. It is thought that organisms possess circadian clocks to facilitate coordination of essential biological events to the external day and night (extrinsic advantage) so as to enhance Darwinian fitness. However, on Earth, there are a number of habitats that are not subject to such robust daily cycling of geo-physical factors. Do organisms living under such conditions exhibit rhythmic behaviours that are driven by endogenous circadian clocks? We attempt to critically survey studies of rhythms (or the lack of them) in organisms living in a range of constant environments. Many such organisms do show rhythms in behaviour and/or physiological variables. We suggest that such presence of rhythms may be indicative of an underlying clock that facilitates, (a) internal synchrony among rhythms, and (b) temporal partitioning of incompatible cellular processes (intrinsic advantage). We then highlight reasons that limit our interpretations about the presence (or absence) of clocks in such organisms living under constant conditions, and suggest possible methods to conclusively test whether or not rhythms in these organisms are driven by endogenous circadian clocks with the hope that it may enhance our understanding of circadian clocks in organisms under constant environments.

Short-Dwell Cycling Intraperitoneal Cefazolin Plus Ceftazidime in Peritoneal Dialysis Patients.

♦ BACKGROUND: Current guidelines suggest that intraperitoneal (IP) antibiotics should be administered only in a long peritoneal dialysis (PD) dwell (≥ 6 hours). The long dwell might result in low ultrafiltration and volume overload. We aim to examine plasma and dialysate concentration of cefazolin and ceftazidime after IP administration in a short-dwell (≤ 2 hours) automated cycling exchange. ♦ METHODS: Stable PD patients without peritonitis were invited to participate in the present study. Patients underwent 5 2-liter exchanges of PD fluid over 10 hours by the PD cycling machine without last fill or additional dwell. Cefazolin and ceftazidime (20 mg/kg each) were added to the first 5-liter bag of 2.5% dextrose PD fluid that was placed on the warmer of the PD cycling machine. Plasma samples were collected at 12 time-points over 24 hours. Dialysate samples from each exchange were also collected. Antibiotic concentrations in plasma and dialysate were then determined by high-performance liquid chromatography (HPLC). ♦ RESULTS: Six stable PD patients without peritonitis participated in the study. Dialysate cefazolin and ceftazidime were consistently high throughout the PD session in all patients (26 - 360 mg/L). Plasma cefazolin and ceftazidime exceeded the minimal inhibitory concentration (MIC) for susceptible organisms (≤ 8 mg/L) within 2 hours (cefazolin 28.5 ± 8.0 and ceftazidime 12.5 ± 3.4 mg/L), peak at 10 hours (51.1 ± 14.1 and 23.0 ± 5.2 mg/L) and sustained well above the MIC at 24 hours (42.0 ± 9.6 and 17.1 ± 3.1 mg/L). ♦ CONCLUSIONS: The short-dwell cycling IP cefazolin and ceftazidime could provide adequate plasma concentration for up to 24 hours. Daily short-dwell cycling IP cefazolin and ceftazidime might be used to treat peritonitis in PD patients already using a PD cycling machine as well as selected continuous ambulatory PD (CAPD) patients who need shorter dwells during peritonitis due to increasing peritoneal solute transport.

Effect of heat waves on embryo mortality in the pine processionary moth.

Extreme climate events such as heat waves are predicted to become more frequent with climate change, representing a challenge for many organisms. The pine processionary moth Thaumetopoea pityocampa is a Mediterranean pine defoliator, which typically lays eggs during the summer. We evaluated the effects of heat waves on egg mortality of three populations with different phenologies: a Portuguese population with a classical life cycle (eggs laid in summer), an allochronic Portuguese population reproducing in spring, and a Tunisian population from the extreme southern limit of T. pityocampa distribution range, in which eggs are laid in fall. We tested the influence of three consecutive hot days on egg survival and development time, using either constant (CT) or daily cycling temperatures (DT) with equivalent mean temperatures. Maximum temperatures (T max) used in the experiment ranged from 36 to 48°C for DT and from 30 to 42°C for CT. Heat waves had a severe negative effect on egg survival when T max reached 42°C for all populations. No embryo survived above this threshold. At high mean temperatures (40°C), significant differences were observed between populations and between DT and CT regimes. Heat waves further increased embryo development time. The knowledge we gained about the upper lethal temperature to embryos of this species will permit better prediction of the potential expansion of this insect under different climate warming scenarios.

Resynchronization Dynamics Reveal that the Ventral Entrains the Dorsal Suprachiasmatic Nucleus.

Although the suprachiasmatic nucleus (SCN) has long been considered the master circadian clock in mammals, the topology of the connections that synchronize daily rhythms among SCN cells is not well understood. We combined experimental and computational methods to infer the directed interactions that mediate circadian synchrony between regions of the SCN. We analyzed PERIOD2 (PER2) expression from SCN slices during and after treatment with tetrodotoxin, allowing us to map connections as cells resynchronized their daily cycling following blockade and restoration of cell-cell communication. Using automated analyses, we found that cells in the dorsal SCN stabilized their periods slower than those in the ventral SCN. A phase-amplitude computational model of the SCN revealed that, to reproduce the experimental results: (1) the ventral SCN had to be more densely connected than the dorsal SCN and (2) the ventral SCN needed strong connections to the dorsal SCN. Taken together, these results provide direct evidence that the ventral SCN entrains the dorsal SCN in constant conditions.

Polymorphisms in the estrogen receptor alpha gene (ESR1), daily cycling estrogen and mammographic density phenotypes.

BackgroundSingle nucleotide polymorphisms (SNPs) involved in the estrogen pathway and SNPs in the estrogen receptor alpha gene (ESR1 6q25) have been linked to breast cancer development, and mammographic density is an established breast cancer risk factor. Whether there is an association between daily estradiol levels, SNPs in ESR1 and premenopausal mammographic density phenotypes is unknown.MethodsWe assessed estradiol in daily saliva samples throughout an entire menstrual cycle in 202 healthy premenopausal women in the Norwegian Energy Balance and Breast Cancer Aspects I study. DNA was genotyped using the Illumina Golden Gate platform. Mammograms were taken between days 7 and 12 of the menstrual cycle, and digitized mammographic density was assessed using a computer-assisted method (Madena). Multivariable regression models were used to study the association between SNPs in ESR1, premenopausal mammographic density phenotypes and daily cycling estradiol.ResultsWe observed inverse linear associations between the minor alleles of eight measured SNPs (rs3020364, rs2474148, rs12154178, rs2347867, rs6927072, rs2982712, rs3020407, rs9322335) and percent mammographic density (p-values: 0.002–0.026), these associations were strongest in lean women (BMI, ≤23.6 kg/m2.). The odds of above-median percent mammographic density (>28.5 %) among women with major homozygous genotypes were 3–6 times higher than those of women with minor homozygous genotypes in seven SNPs. Women with rs3020364 major homozygous genotype had an OR of 6.46 for above-median percent mammographic density (OR: 6.46; 95 % Confidence Interval 1.61, 25.94) when compared to women with the minor homozygous genotype. These associations were not observed in relation to absolute mammographic density. No associations between SNPs and daily cycling estradiol were observed. However, we suggest, based on results of borderline significance (p values: 0.025–0.079) that the level of 17β-estradiol for women with the minor genotype for rs3020364, rs24744148 and rs2982712 were lower throughout the cycle in women with low (<28.5 %) percent mammographic density and higher in women with high (>28.5 %) percent mammographic density, when compared to women with the major genotype.ConclusionOur results support an association between eight selected SNPs in the ESR1 gene and percent mammographic density. The results need to be confirmed in larger studies.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-016-2804-1) contains supplementary material, which is available to authorized users.

On the relevance of using laboratory selection to study the adaptive value of circadian clocks

AbstractThe phrase ‘as sure as night comes after day’ highlights the most conspicuous phenomenon on earth (i.e. the daily cycling of geophysical factors). It is hypothesized that life‐forms on earth have evolved timekeeping mechanisms (circadian clocks) as adaptations to cope with such cyclic variations in their environment and, to test this hypothesis, diverse strategies have been employed. In this review, these different approaches, including comparative, clinal, ecology and/or trait manipulation and laboratory selection strategies are discussed, aiming to evaluate the adaptive value of circadian clocks. The limitations of each of these methods are assessed, and it is suggested that laboratory selection is an ideal, potent and suitable strategy for examining whether circadian clocks are indeed adaptations. In support of this, laboratory selection strategies are highlighted and critically reviewed in a discussion of studies that demonstrate the evolution of circadian clocks and life‐history traits in response to selection for the timing of rhythmic behaviours, as well as those studies that demonstrate the evolution of circadian clocks in response to selection for life‐history traits. Finally, newer approaches are proposed that involve the use of mutants, simultaneous manipulation of multiple environmental factors and genomic technologies in conjunction with laboratory selection to further explore the adaptive significance of circadian clocks.

Association of Neighborhood Walkability With Change in Overweight, Obesity, and Diabetes.

Rates of obesity and diabetes have increased substantially in recent decades; however, the potential role of the built environment in mitigating these trends is unclear. To examine whether walkable urban neighborhoods are associated with a slower increase in overweight, obesity, and diabetes than less walkable ones. Time-series analysis (2001-2012) using annual provincial health care (N ≈ 3 million per year) and biennial Canadian Community Health Survey (N ≈ 5500 per cycle) data for adults (30-64 years) living in Southern Ontario cities. Neighborhood walkability derived from a validated index, with standardized scores ranging from 0 to 100, with higher scores indicating more walkability. Neighborhoods were ranked and classified into quintiles from lowest (quintile 1) to highest (quintile 5) walkability. Annual prevalence of overweight, obesity, and diabetes incidence, adjusted for age, sex, area income, and ethnicity. Among the 8777 neighborhoods included in this study, the median walkability index was 16.8, ranging from 10.1 in quintile 1 to 35.2 in quintile 5. Resident characteristics were generally similar across neighborhoods; however, poverty rates were higher in high- vs low-walkability areas. In 2001, the adjusted prevalence of overweight and obesity was lower in quintile 5 vs quintile 1 (43.3% vs 53.5%; P < .001). Between 2001 and 2012, the prevalence increased in less walkable neighborhoods (absolute change, 5.4% [95% CI, 2.1%-8.8%] in quintile 1, 6.7% [95% CI, 2.3%-11.1%] in quintile 2, and 9.2% [95% CI, 6.2%-12.1%] in quintile 3). The prevalence of overweight and obesity did not significantly change in areas of higher walkability (2.8% [95% CI, -1.4% to 7.0%] in quintile 4 and 2.1% [95% CI, -1.4% to 5.5%] in quintile 5). In 2001, the adjusted diabetes incidence was lower in quintile 5 than other quintiles and declined by 2012 from 7.7 to 6.2 per 1000 persons in quintile 5 (absolute change, -1.5 [95% CI, -2.6 to -0.4]) and 8.7 to 7.6 in quintile 4 (absolute change, -1.1 [95% CI, -2.2 to -0.05]). In contrast, diabetes incidence did not change significantly in less walkable areas (change, -0.65 in quintile 1 [95% CI, -1.65 to 0.39], -0.5 in quintile 2 [95% CI, -1.5 to 0.5], and -0.9 in quintile 3 [95% CI, -1.9 to 0.02]). Rates of walking or cycling and public transit use were significantly higher and that of car use lower in quintile 5 vs quintile 1 at each time point, although daily walking and cycling frequencies increased only modestly from 2001 to 2011 in highly walkable areas. Leisure-time physical activity, diet, and smoking patterns did not vary by walkability (P > .05 for quintile 1 vs quintile 5 for each outcome) and were relatively stable over time. In Ontario, Canada, higher neighborhood walkability was associated with decreased prevalence of overweight and obesity and decreased incidence of diabetes between 2001 and 2012. However, the ecologic nature of these findings and the lack of evidence that more walkable urban neighborhood design was associated with increased physical activity suggest that further research is necessary to assess whether the observed associations are causal.