AAI to DDD pacing mode inappropriate switches in a dual chamber pacemaker due to ventricular blanking period

A 90-year-old woman received a dual chamber pacemaker (PM) for a sick sinus syndrome. The PM was programmed with SafeR AAI-DD pacing mode at 60 bpm. During a standard follow up, some memorized electrograms (EGMs) were found in SafeR diagnostics, with atrial pacing (Ap) not followed by any ventricular sensing/pacing event, due to simultaneous junctional activity falling into ventricular blanking period during Ap and, for this reason, unsensed by the PM. Blanking periods can affect PM functioning if not revealed and adjusted.     

Les sépultures italiennes du Paléolithique supérieur. Reconstitutions du régime alimentaire

The identification of dietary habits is increasingly seen as a fundamental aspect for studying the ancient human populations. Accordingly, several projects aiming to identify Paleolithic individuals’ dietary patterns were developed to analyze the organic component of bone tissue and identify isotopic markers to reconstruct the food typology. Bone fragments from six individuals were selected for carbon and nitrogen stable isotopes analysis. The interpretation of human isotopic data was framed through a dataset of twenty-one Italian Paleolithic individuals. The isotopic data generated for the Paleolithic individuals agree with the information already provided by the archaeological record concerning the Italian hunter and gatherer communities. Their subsistence economy was essentially grounded upon the exploitation of high protein foods, either from terrestrial fauna resources or inland lacustrine or riverine species.     

The plant landscape as inferred from a basket of the Roman town of Privernum (Latium,central Italy)

Abstract

Privernum was a rich Roman colony located 70 km southwest of Rome (southern Latium, central Italy). The archaeobotanical investigations focused on the garden and related structures of the luxury domus della Soglia nilotica. They are archaeologically and radiocarbon dated to the second half of the 1st century AD. The remains of a charred basket were found in the filling of the euripus, an ornamental water basin of the garden. The weaving was made with twisted strands of the leaves of Ampelodesmos mauritanicus (Poir.) T. Durand and Schinz; for the bottom and the handle/s of the basket, wood of evergreen oaks and ash and/or elm, respectively were probably used. The basket contained Pinus pinea seeds and cone scales, and Prunus persica endocarps, which were probably burnt in summer. The sediment in the drainage system and in the kitchen was processed for macro- and microremains. The results indicate the presence of spontaneous ruderal and weed flora elements, typical of human settlement areas, and crops.     

The role of partial incubation and egg repositioning within the clutch in hatching asynchrony and subsequent effects on breeding success

The main mechanism to achieve hatching asynchrony (HA) for incubating birds is to start heating the eggs before clutch completion. This might be achieved through partial incubation and/or early incubation. Even in the absence of incubation behaviour during the laying phase, clutches still experience a certain degree of asynchrony. Recent studies have shown that eggs located in the centre of the nest receive more heat than peripheral ones during incubation. As eggs receiving more heat would develop faster, we hypothesized that HA should be shorter in nests where eggs were moved homogeneously along the centre–periphery space during incubation than in those nests where eggs repeatedly remained in the same locations, either centrally or peripherally. We explored the relative roles of egg repositioning and partial incubation in determining HA in wild birds by (1) removing eggs from 20 Great Tit Parus major nests on the day of laying and replacing them with fake eggs to avoid partial incubation, and returning them when full incubation began; (2) monitoring twice a day the position of each individually marked egg relative to the clutch centre during incubation, and estimating the coefficient of variation of the distances; and (3) determining HA in each nest. Preventing partial incubation reduced HA by 51% days in experimental nests. It also caused negative effects for the incubating females (lengthening the full incubation period) and positive effects for the brood (increasing fledging success). However, our hypothesis about the role of egg repositioning on HA was not supported: all the females moved the eggs with remarkable consistency, generally attaining a coefficient of variation of the distances around 33%, and it was not related to the HA experienced. We therefore conclude that partial incubation is an important factor regulating HA, and females compensate for the potential effects of differential heating by moving the eggs homogeneously within the clutch.     

When an advantageous reproductive trait turns bad: Eggs of the threatened fish Genidens barbus as a natural bait in recreational fisheries

This study describes a recreational fishing method focused on marine catfish, Genidens barbus (Endangered-EN), through the adoption of its eggs as a natural bait during its reproductive period in southern Brazilian ecosystems. Male G. barbus perform parental care, collecting eggs released by females after the fertilization process. Owing to this male behavioural pattern during the reproductive period, these individuals are easily caught in recreational fisheries that use eggs of the same species as a natural bait. The current adoption of G. barbus eggs as bait may intensify the fishing pressure on its populations.     

Genes alternations with exposure time of environmental factors

A theoretical model discussing the environmental factors (EFs) effect of exposure time on genes, which leads to human diseases, is presented using multi-logistic model. The advantages and limitations of this model are discussed in terms of its usefulness for simulating genetic samples. It has been shown that EFs affect genes with the same degree both at high exposure level, low exposure time and at low exposure level, high exposure time.     

Post-parturial reproduction in terrestrial isopods: a partial review

This review deals with some aspects of terrestrial isopod reproduction including breeding season, breeding periods, patterns and strategies, parturition, number and size of broods and mancae. Reproductive period is described by the exact dates (i.e. season) marsupial females were collected in the field, and the duration of the breeding period. The information for both aspects was generally obtained through field work by observing marsupial females. Two reproductive patterns are used by terrestrial isopods, either a discrete (i.e. seasonal) or a continuous (i.e. non-seasonal) pattern. The discrete pattern can be either annual when females breed once a year, or they can breed biannually or multi-annually (two or more times during the year). This conclusion is based generally on observing marsupial females in the field. Therefore, this information does not apply to the reproductive pattern of the individual female since a female may use either or both patterns, i.e. seasonal and continuous. Only by raising individual females singly (with a male) can this point be clarified. This way, the breeding strategy of the same individual female can be studied. The subject is discussed and reviewed based on my research data.     

The Dual-Oscillator System of Drosophila melanogaster Under Natural-Like Temperature Cycles

Dual-oscillator systems that control morning and evening activities can be found in a wide range of animals. The two coupled oscillators track dawn and dusk and flexibly adapt their phase relationship to seasonal changes. This is also true for the fruit fly Drosophila melanogaster that serves as model organism to understand the molecular and anatomical bases of the dual-oscillator system. In the present study, the authors investigated which temperature parameters are crucial for timing morning and evening activity peaks by applying natural-like temperature cycles with different daylengths. The authors found that the morning peak synchronizes to the temperature increase in the morning and the evening peak to the temperature decrease in the afternoon. The two peaks did not occur at fixed absolute temperatures, but responded flexibly to daylength and overall temperature level. Especially, the phase of the evening peak clearly depended on the absolute temperature level: it was delayed at high temperatures, whereas the phase of the M peak was less influenced. This suggests that the two oscillators have different temperature sensitivities. The bimodal activity rhythm was absent in the circadian clock mutants Clk^Jrk and cyc⁰¹ and reduced in per⁰¹ and tim⁰¹ mutants. Whereas the activity of Clk^Jrk mutants just followed the temperature cycles, that of per⁰¹ and tim⁰¹ mutants did not, suggesting that these mutants are not completely clockless. This study revealed new characteristics of the dual-oscillator system in Drosophila that were not detected under different photoperiods. (Author correspondence: yoshii@cc.okayama-u.ac.jp)     

Circadian clock speed increases during aging in the male Syrian hamster: A large-scale study

There are conflicting reports in the literature as to whether or not the circadian period in Syrian hamsters shortens with age, and those studies were conducted with small sample sizes. This report mines data from a large number of experiments resulting in more than 1000 measurements of circadian period in hamsters during aging up to 6 months, and this was correlated with both age and weight. Circadian period was calculated while hamsters were in running wheels in constant darkness. There is a weak correlation between hamster weight and circadian period, and there is significant shortening of circadian period during aging.     

Circadian Time Organization of Professional Firemen: Desynchronization—Tau Differing from 24.0 Hours—Documented by Longitudinal Self-assessment of 16 Variables

We investigated the circadian synchronization/desynchronization (by field-study assessment of differences in period, τ, of 16 coexisting and well-documented rhythms) of 30 healthy firemen (FM) exposed to irregular, difficult, and stressful nocturnal work hours who demonstrated excellent clinical tolerance (allochronism). Three groups of FM were studied (A?=?12 FM on 24-h duty at the fire station; B?=?9 FM on 24-h duty at the emergency call center; C?=?9 day-shift administrative FM) of mostly comparable average age, body mass index, career duration, chronotype—morningness/eveningness, and trait of field dependence/independence. The self-assessed 16 circadian rhythms were (i) physiological ones of sleep-wake (sleep log), activity-rest (actography), body temperature (internal transmitter pill probe), right- and left-hand grip strength (hand dynamometer), systolic and diastolic blood pressure (BP) plus heart rate (ambulatory BP monitoring device); (ii) psychological ones (visual analog self-rating scales) of sleepiness, fatigue, fitness for work, and capacity to cope with aggressive social behavior; and (iii) cognitive ones of eye-hand skill and letter cancellation, entailing performance speed (tasks completed/unit time) and accuracy (errors). Data (4–6 time points/24?h; 2 591 480 values in total) were gathered continuously throughout two 8-d spans, one in winter 2010–2011 and one in summer 2011. Each of the resulting 938 unequal-interval time series was analyzed by a special power spectrum analysis to objectively determine the prominent τ. The desynchronization ratio (DR: number of study variables with τ?=?24.0?h/number of study variables?×?100) served to ascertain the strength/weakness of each rhythm per individual, group, and season. The field study confirmed, independent of group and season, coexistence of rather strong and weak circadian oscillators. Interindividual differences in DR were detected between groups and seasons (χ², correlation tests, analysis of variance [ANOVA]). Moreover, in each group, both in winter and summer, a normal distribution was observed in the number of FM with rhythms with τ?=?24.0?h, e.g., ranging from 5/16 (large desynchronization) to 16/16 (no desynchronization). Such a normal distribution with intraindividual stability over time (i.e., seasons) is consistent with the hypothesis of an inherited origin of a differential propensity to circadian desynchronization and which is supported by the distribution of τs in winter and summer following the Dian-Circadian Genetic Model, i.e., with τ?=?24.0?h, τ?=?24.0?h?+?n(0.8?h), and τ?=?24.0?h???n(0.8?h).