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The long-term impact of seasonal regulation of clocks (Daylight Saving Time) is analyzed showing that it helped to mitigate the advance of the phase of human activity during the twentieth century and the exposure to the hours of the dawn in winter. The increased risks induced by circadian misalignment around transition dates are balanced by a better alignment of social clocks to the natural day in summer and in winter.

The partially overlapped ferroelastic/martensitic and para-ferromagnetic phase transitions of a Ni$_{50.53}$Mn${33.65}$In$_{15.82}$ metamagnetic shape memory alloy have been studied from calorimetric, magnetic and acoustic emission measurement. We have taken advantage of the existence of thermal hysteresis of the first order ferroelastic/martensitic phase transition ($\sim2.5$K) to discriminate the latent heat contribution $\Delta$Ht = 7.21(15) kJ/kg and the specific heat contribution $\Delta$Hc = 216(1) J/kg to the total excess enthalpy of the phase transition. The specific heat was found to follow a step-like behavior at this phase transition. The intermittent dynamics of the ferroelastic/martensitic transition has been characterized as a series of avalanches detected both from acoustic emission and calorimetric measurements. The energy distribution of these avalanche events was found to follow a power law with a characteristic energy exponent $\epsilon\sim2$ which is in agreement with the expected value for a system undergoing a symmetry change from cubic to monoclinic. Finally, the critical behavior of the para-ferromagnetic austenite phase transition that takes place at $\sim 311$K has been studied from the behavior of the specific heat. A critical exponent $\alpha\sim0.09$ has been obtained, which has been shown to be in agreement with previous values reported for Ni-Mn-Ga alloys but different from the critical divergence reported for pure Ni., Comment: 18 pages, 11 figures

Spanish NUTS3 region records of age specific weekly deaths since the year 2020, records of age specific COVID–19 deaths and age specific population since the year 2020 are used to estimate first age specific all–cause death rates and age specific COVID–19 undercount.Results shows a statistically significant impact of the pandemic in excess deaths for population aged 40 and elder. Statistically significant COVID–19 undercount is identified only for population aged 80 and elder. Very likely this is the result of the impact of the pandemic in institutionalized population at the early stages of the pandemic.

A new method that characterizes thermal properties during a first-order phase transition is described. The technique consists in exciting the sample by a series of constant frequency thermal pulses which one in every N pulses –N is a small number like four—being exceedingly large in amplitude. This pulse induces phase transformation which is inhibited during the following smaller pulses due to thermal hysteresis. That way the specific heat capacity for a given mixture of phases can be determined. The results obtained are independent of experimental parameters like the rate and the amplitude of the pulses, unlike what happens in other calorimetric techniques. The method also provides the enthalpy excess by analysing the energy balance between the dissipated heat and the heat flowing during each pulse of measurement. The protocol is tested to analyse the phase transitions of a Heusler alloy Ni50.53Mn33.65In15.82. The paramagnetic-ferromagnetic transition for the austenite phase is continuous and the specific heat capacity shows a lambda anomaly. The martensitic phase transition shows a first-order character and the specific heat capacity follows a step-like behaviour.

Excess death rates E during the spring of 2020 are computed in N=340 level 3 European territorial units for statistics ---NUTS3 in Netherlands (44), Belgium (40), France (96), Spain (50) and Italy (110)--- from 2020 provisional week deaths, the population numbers for 2020, and observations in previous years (reference or baseline), all of them obtained from Eurostat web page. The distribution of excess death rates is found to follow an exponential law with empirical complementary cumulative distribution function Y following logY=a+b(E-Eave)/s. In the middle of the distribution b1=-1.356± 0.009; R2=0.998 are found and for the largest m=46 excess death rates b1=-0.645± 0.018; R2=0.992 is observed. This result suggests that abnormally large excess death rates may develop in statistical regions independently of what happens in the outside. Distribution of excess death rates are also analyzed on a country basis. A two-sample Kolmogorov-Smirnov test does not reject the null hypothesis "normal values of E for country i and country j come from the same parent distribution" for any pairing. This is an evidence of a common background in the outcomes. In other words statistical differences among countries can be characterized by averages and standard deviations only. Average death rates, sample standard deviations, excess death tolls are: Netherlands 407×10-6,387× 10-6,8104; Belgium 667×10-6,364× 10-6,8436; France 228× 10-6,377×10-6,21780 (overseas departments not included); Spain 1059× 10-6,1149×10-6,48931 (Canary Islands not included); Italy 791× 10-6,1140× 10-6,49184; and 610× 10-6,877× 10-6,136435 for the combined distribution. A Kolmogorov-Smirnov test rejects (p

Spanish official records of mortality and population during the 21st century are analyzed to determine the age-sex specific crude death rate in the 2020 spring (week 10 to week 21) COVID-19 outbreak . Age-sex specific cumulative death rates can be modeled by a Poisson regression with rate linearly varying with calendar year from which age-sex specific reference value for 2020 are obtained. Excess death rate increases exponentially with age showing a doubling time [4.1,4.9] years (female) and [4.8,5.4] years (male). Age specific infection fatality rate doubling times below age 70 years are reported as [4.7,8.8] years (female) and [4.8,6.6] years (male). Infection fatality rate for people aged more than 80 is discussed in relation to the shares of people living in institutionalized long term care facilities.

ObjectivesAssess the impact of the illness designated COVID–19 during the first year of pandemic outbreak in Spain through age/sex–specific death rates.Study designAge/sex–specific weeekly deaths in Spain were retrieved from Eurostat. Spanish resident population was obtained from the National Statistics Office.MethodsGeneralized linear Poisson regressions were used to compute the contrafactual expected rates after one year (52 weeks or 364 days) of the pandemic onset. From this one–year age/sex–specific and age/sex–adjusted mortality excess rates were deduced.ResultsFor the past continued 13 years one–year age/sex–adjusted death rates had not been as high as the rate observed on February 28th, 2021.The excess death rate was estimated as 1.790×10−3 (95 % confidence interval, 1.773×10−3 to 1.808×10−3; P−score = 20.2 % and z−score = 11.4) with an unbiased standard deviation of the residuals equal to 157×10−6. This made 84 849 excess deaths (84 008 to 85 690). Sex disaggregation resulted in 44 887 (44 470 to 45 303) male excess deaths and 39 947 (39 524 to 40 371) female excess deaths.ConclusionWith 73 571 COVID–19 deaths and 9772 COVID–19 suspected deaths that occurred in nursing homes during the spring of 2020 it is only 1496 excess deaths (1.8 %, a z−score of 0.2) that remains unattributed.The infection rate during the first year of the pandemic is estimated in 16 % of population after comparing the ENE–COVID seroprevalence, the excess deaths at the end of the spring 2020 and the excess deaths at the end of the first year of the pandemic.

On January 30, 2020 Current Biology released the report "A Chronobiological Evaluation of the Acute Effects of Daylight Saving Time on Traffic Accident Risk" doi: https://doi.org/10.1016/j.cub.2019.12.045 by Fritz, et al., where it was argued that fatal traffic accident risk increases by 6% in the US due to Daylight Saving Time spring transition. This manuscript is a 1000 word correspondence showing that the bulk of this reported risk comes from the transition dates mandated by the Energy Policy Act in 2007., Comment: 1100 words comment letter. This is the accepted manuscript of a correspondence published by Current Biology (2020)

A Letter to the Editor published in the Journal of Sleep Research, Comment: 3pages, 1figure, 740 words, RevTeX RMP format, longbibliography

1000 words comment on a paper published in the European Journal of Internal Medicine by a panel of experts. My point is authors address the magnitude of the change (one hour) but fail to consider in any way its seasonal features. DST is not a random change of an hour but an specific change on specific dates and in a specific direction ---spring forward, fall back---. DST is the way many contemporary societies handles the seasonality. The way many contemporary societies turn a nonseasonal clock (the mechanical clock) into a seasonal clock., Comment: 1000 words, 1 figure, revtex two column (2 pages). Published in the European Journal of Internal Medicine

We have combined high sensitivity, extra-low differential temperature scanning rate calorimetry, and acoustic emission (AE) measurements to study avalanches during the cubic \ensuremath{\leftrightarrow} 18R martensitic transition of a Cu-Al-Be single crystalline shape memory alloy. Both AE and calorimetry corroborate a good power-law behavior for cooling with an exponent $\ensuremath{\varepsilon}\ensuremath{\simeq}1.6$. For heating, a slope is observed in the maximum likelihood curves, which confirms that our data are affected by an exponential cutoff. An effective energy exponent, $\ensuremath{\varepsilon}\ensuremath{\sim}1.85$, and a cutoff, ${\ensuremath{\lambda}}^{\ensuremath{-}1}=0.115(38)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}\phantom{\rule{0.16em}{0ex}}\mathrm{aJ}$, were determined by fits of power-laws with exponential damping. The long tail observed in the low-temperature region by calorimetric measurements suggests the existence of significant elastic effects that constrain the progress of the transformation at low temperatures. While thermodynamic features such as transformation enthalpy and entropy are those expected for Cu-based shape-memory alloys undergoing a cubic \ensuremath{\leftrightarrow} 18R transition, the critical behavior deviates from the corresponding behavior expected from this symmetry change. These deviations are a consequence of the elastic hardening induced by the interplay of the transformation with dislocation jamming, which has the effect of effectively reducing the number of pathways connecting the parent and martensitic phase.

Analysis of time use surveys in seventeen European countries and two American countries suggest that the winter sunrise —the latest sunrise year round— is a synchronizer for the sleep/wake cycle in standard population below 54° latitude, in competition with the noon synchronizer.When comparing industrialized data to data from hunter/gatherer, pre-industrial, Tropical societies only the late event survives as a synchronizer below 54° latitude. People rise immediately before sunrise —winter sunrise in industrialized mid-latitude societies— and abhor morning darkness. Synchronization propagates through the sleep/wake cycle so that people go to bed with increasing distance to sunset in winter as latitude increases in a scenario dominated by artificial light. This suggests a leading role of the homeostatic sleep pressure in understanding sleep/wake cycle at social level.WARNINGThis pre-print has been largely upgraded and restyled in “Sleep timing in industrial and pre-industrial societies sync to the light/dark cycle” (https://doi.org/10.1101/392035). In this new pre-print data coming from the Harmonsized European Time Use Surveys (HETUS) and referred to the “sleep/wake and other personal care” cycle were not analyzed. Instead two new pre-industrial data are included.Therefore this old pre-print you are about to read remains as a source for these data (see Figure 3 and Table III, Table VII to IX) and a source of information in the range of latitude above 54°.

This work analyzes time use surveys from 19 countries (17 European and 2 American) in the middle latitude range from 38{\deg} to 61{\deg} latitude accounting for 45% of world population in that range. Time marks for primary activities (sleeping, working and eating) are systematically contrasted against light/dark conditions related to latitude. The analysis reveals that winter sunrise is a synchronizer for labor start time below 54{\deg} where they occur within the winter civil twilight region. Winter sunset is a source of synchronization for labor end times. Winter terminator also punctuate meal times in Europe with dinner times occurring 3h after winter sunset time within a strip of 1h, which is 40% narrower than variability of dinner local times. The sleep-wake cycle of laborers in a weekday is shown to be related to winter sunrise whereas standard population's cycle appears to be irrespective of latitude. The significance of the winter terminator depends on two competing factors average daily labor time (some 7h30m) and winter daytime ---the shortest photoperiod---. Winter terminator gains significance when shortest photoperiod roughly matches to daily labor time plus a reasonable lunch break. That is within a latitude range from 38{\deg} to 54{\deg}. The significance of winter terminator as a source of synchronization is also related to contemporary year round time schedules: the shortest photoperiod represents the worst case scenario the society faces. Average daily sleep times show little trend with the shortest photoperiod slope 5min/h for a Pearson coefficient $r^2=0.242$. Average labor time may have a weak coupling with the shortest photoperiod: slope 29min/h for $r^2=0.338$., Comment: Changes: Descriptive statistics and bivariate correlations added. Introduction, Results and Discussion largely modified. RevTeX4-1 27 pages, 6 figures, 13 tables. Data from Time Use Surveys, Hetus and Eurostat

Calorimetric, elastic, and polar properties of ferrolectric lead scandium tantalate PbSc0.5Ta0.5O3 with 65% cation order have been investigated in the vicinity of the paraelectric-ferroelectric transition at T trans = 295 K. Comparison of temperature dependencies of the excess specific heat and elastic properties indicates that both anomalies stem from thermal fluctuations of order parameters in three dimensions. These fluctuations are consistent with the tweed microstructure. This transition is driven by several coupled thermodynamic order parameters, as evidenced by a strongly nonlinear scaling of the excess entropy with the squared ferroelectric polarization.Calorimetric, elastic, and polar properties of ferrolectric lead scandium tantalate PbSc0.5Ta0.5O3 with 65% cation order have been investigated in the vicinity of the paraelectric-ferroelectric transition at T trans = 295 K. Comparison of temperature dependencies of the excess specific heat and elastic properties indicates that both anomalies stem from thermal fluctuations of order parameters in three dimensions. These fluctuations are consistent with the tweed microstructure. This transition is driven by several coupled thermodynamic order parameters, as evidenced by a strongly nonlinear scaling of the excess entropy with the squared ferroelectric polarization.

The first-order diffusionless structural phase transition in Cu67.64Zn16.71Al15.65 is characterized by jerky propagation of phase front related to the appearance of avalanches. In this work we describe a full analysis of this avalanche behaviour using calorimetric heat-flux measurements and the results are compared with acoustic emission (AE) measurements.

We studied the two-step martensitic transition of a Cu-Al-Ni shape-memory alloy by calorimetry, acoustic emission (AE), and resonant ultrasound spectroscopy (RUS) measurements. The transition occurs under cooling from the cubic (β, Fm3m) parent phase near 242 K to a mixture of orthorhombic 2H and monoclinic 18R phases. Heating leads first to the back transformation of small 18R domains to β and/or 2H near 255 K, and then to the transformation 2H to β near 280 K. The total transformation enthalpy is ΔHT=328±10 J/mol and is observed as one large latent heat peak under cooling. The back-transformation entropy under heating breaks down into a large component 18R to β at 255 K and a smaller, smeared component of the transformation 2H to β near 280 K. The proportions inside the phase mixture depend on the thermal history of the sample. The elastic response of the sample is dominated by large elastic softening during cooling. The weakening of the elastic shear modulus shows a peak at 242 K, which is typical for the formation of complex microstructures. Cooling the sample further leads to additional changes of the microstructure and domain wall freezing, which is seen by gradual elastic hardening and increasing damping of the RUS signal. Heating from 220 K to room temperature leads to elastic anomalies due to the initial transformation, which is now shifted to high temperatures. The transition is smeared over a wider temperature interval and shows strong elastic damping. The shear modulus of the cubic phase is recovered at 280 K. The phase transformation leads to avalanches, which were recorded by AE and by time-resolved calorimetry. The cooling transition shows very extended avalanche signals in calorimetry with power-law distributions. Cooling and heating runs show AE signals over a large temperature interval above 260 K. Splitting the transformation into two martensite phases leads to power-law exponents ɛ∼2 (β↔ 18R) and ɛ∼1.5 (β↔ 2H) while the phase mixture shows an effective AE exponent of 1.7.

Using the SMDTA technique, thermal properties and kinetics of the ferroelectric phase transition in a highly deuterated triglycine selenate sample have been studied under electric field E. For E = 0 and due to an internal break in the sample, the transition is carried out in two stages whose temperatures differ in about 0.1 K. The specific heat follows the Landau theory predictions even in the coexistence interval. The latent heat has been evaluated to be 1.32 Jg −1 on cooling and 1.08 Jg −1 on heating for E = 0. The different values on heating and on cooling for E = 0 are explained in terms of thermal hysteresis. The specific heat, the latent heat and the kinetics of the transformation have investigated for E = 800 Vcm −1 . The latent heat under this field is found to be 1.25 Jg −1 on cooling and 0.65 Jg −1 on heating.

The specific heat, heat flux (DTA trace) and dielectric constant of KDP ferroelectric crystal have been measured simultaneously for various electric fields with a conduction calorimeter. The specific heat presents a strong anomaly but these simultaneous measurements allow us to evaluate the latent heat accurately. Latent heat decreases with field and the value of critical electric field --that where latent heat disappears-- is estimated to be (0.44\pm0.03) kV/cm. Incidentally, we have measured simultaneously the dielectric permittivity which suggests that latent heat is developed as domains are growing., Comment: 7 pages, 6 figures, ReVTeX, twocolumn format, to appear in J. Phys. Cond. Matter

We revisit the relationship between the Nernst theorem and the Kelvin-Planck statement of the second law. We propose that the exchange of entropy uniformly vanishes as the temperature goes to zero. The analysis of this assumption shows that is equivalent to the fact that the compensation of a Carnot engine scales with the absorbed heat so that the Nernst theorem should be embedded in the statement of the second law. ----- Se analiza la relaci{\'o}n entre el teorema de Nernst y el enunciado de Kelvin-Planck del segundo principio de la termodin{\'a}mica. Se{\~n}alamos el hecho de que el cambio de entrop{\'\i}a tiende uniformemente a cero cuando la temperatura tiende a cero. El an{\'a}lisis de esta hip{\'o}tesis muestra que es equivalente al hecho de que la compensaci{\'o}n de una m{\'a}quina de Carnot escala con el calor absorbido del foco caliente, de forma que el teorema de Nernst puede derivarse del enunciado del segundo principio., Comment: 8pp, 4 ff. Original in english. Also available translation into spanish. Twocolumn format. RevTeX

KMnF 3 and DKDP crystals have been studied around their phase transitions using a conduction calorimetry technique where a long periodical square thermal pulse (0.05 K in amplitude) is superposed to a heating or cooling ramp as low as 0.06 K h −1 . Specific heat data obtained in the dissipation and relaxation semiperiods of the square pulse become different inside the phase transition interval. The electromotive force developed by the heat fluxmeters at the end of the relaxation semiperiod (underlying signal) is compared with the DTA trace obtained in a second run with the same temperature ramp but without the modulated perturbation. The comparison between the DTA trace and specific heat data obtained in the first run allows us to determine the value of the latent heat and to obtain information about the kinetic of the phase transition.

The specific heat of lawsonite, CaAl 2 Si 2 O 7 (OH) 2 .H 2 O, has been measured in the temperature range 125 K - 325 K. An anomaly is seen at 273 K, which is related to the Cmcm — Pmcn phase transition. The magnitude of the total excess entropy associated with this transition is not reproducible, varying in the range 5.93 — 6.24 J K −1 mol −1 . On heating, the specific heat anomaly is consistent with a tricritical phase transition. However, on cooling, significant hysteresis is observed, and the form of the C P anomaly is quite different. In all measurements extensive pre-transitional effects are observed above T C . Analysis of existing specific heat data in the temperature range 75 K — 175 K shows an anomaly associated with the Pmcn — P2 1 cn phase transition. The excess entropy associated with this transition is 6 (1) J K −1 mol −1 . These data are interpreted as showing that both transitions are caused by the interaction of proton ordering and displacive changes in the aluminosilicate framework. The standard entropy of lawsonite at 298 K is recalculated, incorporating the effects of the two transitions. Two methods are used for this recalculation, giving values of S 0 298 = 233.27 and 234.96 JK −1 mol −1 respectively.

The commensurate-incommensurate phase transition of a Rb2 ZnCl4 crystal was studied using a conduction calorimeter. By identifying the contribution of the specific heat to the transition enthalpy it was possible to show, for the first time for a compound of this type, transition latent heat. This was estimated to be Q = 2.3 J mol-1 . The result was compared with theoretical predictions for a domain wall model having repulsive-attractive interaction; satisfactory results were obtained for the first time. The same analysis was applied to the normal-incommensurate phase transition and no latent heat was observed, as expected.

The commensurate-incommensurate phase transition of a Rb2CoCl4 crystal has been studied. The study covers the simultaneous measurement of thermal and dielectric properties. We obtain that transition enthalpy is 5.0Jmol−1. This result is similar to that obtained on Rb2CoCl4 and the relative position of dielectric permittivity anomaly and heat flux anomaly is also found to be consistent with previous experiments on Rb2CoCl4.

The decay of the permittivity of Rb 2 ZnCl 4 is studied over ten days in the commensurate phase. No equilibrium state is actually found after an experience of twelve days. Assuming that the heating branch may represent the equilibrium state a three-component relaxation law is obtained with three different relaxation time. These relaxation times are connected to three different mechanisms of permittivity decay: six domain wall merging, pair annihilation and pinning to defects.

The specific heat, heat flux (DTA trace) of KH2PO4 ferroelectric crystals have been measured simultaneously under an applied electric field with a conduction calorimeter. The specific heat presents a strong anomaly and these simultaneous measurements allow us to evaluate the latent heat accurately.

Crackling noise and avalanches during the martensite phase transformation of Cu67.64Zn16.71Al15.65 were investigated. Heat flux measurements with extremely slow heating rates of 0.005 Kh -1 allowed sufficient separation between the continuous background and the avalanche jerks. The jerk enthalpy is below 3 of the total transformation enthalpy. The crackling noise follows power law behavior with an energy exponent near ε=1.8. The jerks are almost uncorrelated with approximately a Poisson distribution of the waiting times between jerks. Quantitative analysis showed a scaling behavior with p(wt) ∿ wt (γ-1)exp(-wt/Ï„)n with γ=0.7 and n ≈ 1. © 2011 American Institute of Physics., The calorimetric experiments have been supported in Seville by Project FIS2006-04045. J. Manchado wishes to thank to Fundacio´n Ca´mara for a research grant. We want to thank also to Dr. A. Planes for supplying the sample.

The ferroelectric phase transition of three single crystals of TGSe1−x DTGSex has been described by using specific heat, latent heat, and dielectric permittivity measurements. Pure, half-deuterated, and highly-deuterated TGSe single crystals were analyzed. Transition temperature and latent heat increase with increasing deuteration. Irrespective of the degree of deuteration, a 2-4-6 Landau model is suitable to describe the phase transition. The fourth-rank prefactor in Landau potential is found to be very sensitive to deuteration while the second-rank and the sixth-rank prefactors smoothly change with composition. The pyroelectric figure of merit for these materials has also been derived from the theoretical model. Gobierno de España-FIS2006-04045

The asymptotic behaviour near phase transitions can be suitably characterized by the scaling of $\Delta s/Q^2$ with $\epsilon=1-T/T_c$, where $\Delta s$ is the excess entropy and $Q$ is the order parameter. As $\Delta s$ is obtained by integration of the experimental excess specific heat of the transition $\Delta c$, it displays little experimental noise so that the curve $\log(\Delta s/Q^2)$ versus $\log\epsilon$ is better constrained than, say, $\log\Delta c$ versus $\log\epsilon$. The behaviour of $\Delta s/Q^2$ for different universality classes is presented and compared. In all cases, it clearly deviates from being a constant. The determination of this function can then be an effective method to distinguish asymptotic critical behaviour. For comparison, experimental data for three very different systems, Rb2CoF4, Rb2ZnCl4 and SrTiO3, are analysed under this approach. In SrTiO3, the function $\Delta s/Q^2$ does not deviate within experimental resolution from a straight line so that, although Q can be fitted with a non mean-field exponent, the data can be explained by a classical Landau mean-field behaviour. In contrast, the behaviour of $\Delta s/Q^2$ for the antiferromagnetic transition in Rb2CoF4 and the normal-incommensurate phase transition in Rb2ZCl4 is fully consistent with the asymptotic critical behaviour of the universality class corresponding to each case. This analysis supports, therefore, the claim that incommensurate phase transitions in general, and the A$_2$BX$_4$ compounds in particular, in contrast with most structural phase transitions, have critical regions large enough to be observable., Comment: 13 pp. 9 ff. 2 tab. RevTeX. Submitted to J. Phys.: Cond. Matter

The influence of a transverse electric field in the specific heat of triglycine sulphate (TGS) has been studied. The specific heat of TGS has been measured heating the sample from ferroelectric to paraelectric phase after prolonged transverse electric field (i.e. perpendicular to the ferroelectric axis). It is shown that the specific heat of TGS can remember the temperature $T_s$ at which the transverse field was previously applied., ReVTeX4 Twocolumn 4 pages, 4 figures

The existence of temporal correlations during the intermittent dynamics of a thermally driven structural phase transition is studied in a Cu–Zn–Al alloy. The sequence of avalanches is observed by means of two techniques: acoustic emission and high sensitivity calorimetry. Both methods reveal the existence of event clustering in a way that is equivalent to the Omori correlations between aftershocks in earthquakes as are commonly used in seismology.