Log Period Research Articles

On the Dynamical Erasure of Initial Conditions in Multi-planetary Systems

Do sub-Neptunes assemble close to where we see them or do they form full-fledged farther away from their host star then migrate inwards? We explore this question using the distribution of measured orbital periods, one of the most fundamental observable parameters. Under disk-induced migration, planet occurrence rate is expected to decrease toward shorter orbital periods. Presently, the observed sub-Neptune period distribution is flat in log period, between 10 and 300 days. We show, using N-body integration, how post-disk dynamical instabilities and mergers in multi-planetary systems erase the initial conditions of migration emplaced in period distributions over 10 s to 100 Myr timescale, in rough agreement with an observational hint of the abundance of resonant pairs for systems younger than 100 Myr which drops dramatically for more evolved systems. We comment on caveats and future work.

The Bound Test Approach of the Money Demand Determinants in Nepal

The theory of money demand is an empirically tested theory of Nepal. It aimed at estimating the money demand function in Nepal. The causal research designs were used for the study. An annual time series from 1980/81 to 2021/22 was used as the data. The research used the Bound test and Auto-regressive Distributive lag model (ARDL). Moreover, a unit root test, bound test, stability diagnostic test, and normality test were used. The empirical result indicates the existence of both short-run and long-run relationships between money demand and real gross domestic production. Furthermore, money demand has a good short-run association with inflation and the consumer price index, whereas it has a long-run relationship. The disequilibrium is corrected in the one log period with a speed of adjustment of 0.75 percent. The study concludes an association between broad money supply and real gross domestic production in Nepal exists.

Применение канатно-рельсовых дорог для трелевки сортиментов

The article presents constraining factors of the use of traditional approaches for timber skidding in the winter logging period in the North-West Federal District of the Russian Federation. Based on the study of scientific literature, the classification of cable-railways is given, methods of fastening the platform or cable car to the traction cable, the peculiarities of cable selection are considered. The modes of operation of cable-railways are described (without an engine – as a timber slide, with an engine without a trailing cable, with an engine with a trailing cable), the basic requirements for cable-railways and factors limiting the scope of application of such roads are considered. A methodology for determining the driving forces is proposed. It takes into account the weight of the car moving on the slope, the number of cars, the angle of inclination of the track section, the resistance to car movement, additional resistance to car movement when passing curves, the weight of the cable, its length, the friction of the cable on the ground, sleepers and other obstacles, which depends on the condition of the track structure, the density of sleeper laying, ballast protruding on the surface, cable lubrication and other factors. In addition to the above, power losses from the resistance of track rollers when they are enveloped by the running down branch of the cable, friction losses in the trunnions of the winch drums and friction losses from the cable enveloping the winch drums were considered. The article discusses the conditions under which it is possible to move the car down the slope, as well as prevent slipping and provide cable braking in the grooves of the drums. Limitations for the use of cable-railways, depending on the nature of the track, rolling stock, slope angle of the track, average skidding distance, are determined. A technical solution to improve the existing cable-railways using an articulated carriage that increases the operational properties of cable-railways, is proposed. The proposed design allows to reduce the wear of cables and to organize timber harvesting, including on nonstraight skidding trails with rotation angles up to 45 degrees. At the same time, the design of the articulated carriage can be effectively applied on cable-railways already in operation. For citation: Svoykin F.V., Svoykin V.F., Sokolova V.A., Voinash S.A., Ariko S.Ye. Application of Cable-Railways for Timber Skidding. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 5, pp. 115–125. (In Russ.). https://doi.org/10.37482/0536-1036-2023-5-115-125

Improving data accessibility and application for underground climate re-search at the British Geological Survey

Improving data accessibility and application for underground climate re-search at the British Geological Survey

Analysis of Roll Decay for Surface-Ship Model Experiments With Uncertainty Estimates

Abstract Roll decay of David Taylor model basin (DTMB) Model 5720, a 23rd-scale free-running model of the research vessel (R/V) Melville, is evaluated with uncertainty estimates. Experimental roll-decay time series was accurately modeled as an exponentially decaying cosine function, which is the solution of a second-order ordinary differential equation for damping coefficient of less than one (N < 1). The curve-fit provides damping coefficient (N), period (T), and offset. Roll period in calm water was dependent on Froude number (Fr) and initial roll angle (a). Roll decay data are from 76 runs for three nominal Froude numbers, Fr = 0, 0.15, and 0.22. The initial roll angle variation was 3 deg–25 deg. The natural roll period was 2.139 ± 0.041 s (±1.9%). The decay coefficient data were approximated by a plane in three dimensions with Fr and initial roll amplitudes (a) as the independent variables. Curve-fit results are compared to decay coefficient by log decrement and period from time between zero crossings. Examples demonstrate average values for a single roll decay event from log decrement are the same as values by the curve-fitting method within uncertainty estimates. The uncertainty estimate for the decay coefficient is significantly less by curve-fit method in comparison to log-decrement method. By log decrement, the relative uncertainty increases with decreasing roll amplitude peak; consequently, focus should be on the damping coefficient at the largest peaks, where the uncertainty is the smallest.

Seventy years of watershed response to floods and changing forestry practices in western Oregon, USA

AbstractThis study examined the 70‐year history of clearcutting of old‐growth forest and associated road construction, floods, landslides, large wood in rivers, and channel change in the 64 km2 Lookout Creek watershed in western Oregon, where forestry practices began in 1950 and largely ceased by the 1980s. Responses differed among three zones with distinctive geomorphic processes within the watershed: a glacially sculpted zone, an earthflow‐dominated zone, and a debris slide and debris flow‐dominated zone. Watershed response to floods was more related to the timing of road construction and clearcuts, past geomorphic events, and forest dynamics than to flood magnitude. Even small (1–3 year) floods generated geomorphic responses in the period of initial road construction and logging (1950–1964) and during ongoing logging in the early part of a 30‐year period between large flood events (1966–1995). The floods of 1964/65, 15 years after the onset of logging, produced much larger geomorphic responses than the flood of record (1996), more than a decade after logging ceased. Geomorphic response was negligible for the third largest event on record (2011) during the last period (1997–2020), when former clearcuts were 20 to 70‐year‐old forest plantations. Watershed response in each of five distinct time periods depended on conditions created during prior periods in the three zones. Understanding of watershed response to forestry requires integrated observation of forestry practices, floods, landslide susceptibility, wood delivery and movement, and channel change on time scales that capture responses to past and ongoing management practices and geophysical and biological factors and events.

An Inhomogeneous Plane-Wave Based Single-Level Fast Direct Solver for the Scattering Analysis of Extremely Large Antenna Arrays

A semianalytic single-level fast direct solver (FDS) is presented for the method-of-moments (MoM) analysis of large planar antenna arrays with up to few thousands of complex elements on current desktop computers. Assuming a partition of the impedance matrix, the proposed scheme factorizes the near-field blocks via a singular value decomposition (SVD)-based low-rank approximation and the intermediate-field blocks via an analytical inhomogeneous plane-wave (IPW) expansion. The near- and intermediate-field bases are then unified to leverage the Woodbury formula for the inversion. The solutions for the excitation of each array ports are obtained at once with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$O(N^{15/7} \ln ^{3} N)$ </tex-math></inline-formula> computational cost and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$O(N^{11/7} \ln N)$ </tex-math></inline-formula> memory for array problems with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N$ </tex-math></inline-formula> basis functions. The complexities are traced precisely and the error is controlled by means of analytical formulas for the required number of IPWs. The FDS is also combined with a macrobasis function (MBF) approach to deal with antenna geometries containing many subwavelength details. This article includes simulations of regular arrays of about <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$169^{2}~3$ </tex-math></inline-formula> -D dipoles and an irregular array composed of seven stations of the low-frequency square kilometer array (SKA) telescope comprising each 256 log-periodic (LP) antennas. The proposed FDS allows the analysis of the coupling effect both within any one station but also between the stations of the telescope, a size and complexity of problem which has not been possible with existing published techniques.

Drilling into mines for heat: geological synthesis of the UK Geoenergy Observatory in Glasgow and implications for mine water heat resources

Thermal energy from groundwater in abandoned, flooded, coal mines has the potential to make a significant contribution to decarbonization of heat and net-zero carbon emissions. In Glasgow, UK, a subsurface observatory has been constructed for mine water heat and heat storage research. We synthesize geological and mine water resource findings from a 4 year period of borehole planning, drilling, logging and testing. The heterogeneous bedrock is typical of the Scottish Coal Measures Group, whereas superficial deposits are more sand- and gravel-dominated than predicted. Mine water boreholes encountered workings in the Glasgow Upper, Glasgow Ell and Glasgow Main coal seams, proving water-filled voids, mine waste, fractured rock mass and intact coal pillars, with high yields on initial hydrogeological testing. Although the depth and extent of mine workings delineated on mine abandonment plans proved accurate, metre-scale variability was expected and proved in the boreholes. A mine water reservoir classification established from the observatory boreholes highlights the resource potential in areas of total extraction, stowage, and stoop and room workings. Because their spatial extent is more extensive across the UK than shafts or roadways, increasing the mine water energy evidence base and reducing exploration risk in these types of legacy workings is important. Supplementary material: Borehole reports and other datasets are available at https://ukgeos.ac.uk/data-downloads (mixture of over 20 DOI datasets and reports or data packs published openly on https://nora.nerc.ac.uk ; all material is deposited in the National Geoscience Data Centre).

Simultaneous inference of periods and period-luminosity relations for Mira variable stars

The period-luminosity relation (PLR) of Mira variable stars is an important tool to determine astronomical distances. The common approach of estimating the PLR is a two-step procedure that first estimates the Mira periods and then runs a linear regression of magnitude on log period. When the light curves are sparse and noisy, the accuracy of period estimation decreases and can suffer from aliasing effects. Some methods improve accuracy by incorporating complex model structures at the expense of significant computational costs. Another drawback of existing methods is that they only provide point estimation without proper estimation of uncertainty. To overcome these challenges, we develop a hierarchical Bayesian model that simultaneously models the quasi-periodic variations for a collection of Mira light curves while estimating their common PLR. By borrowing strengths through the PLR, our method automatically reduces the aliasing effect, improves the accuracy of period estimation and is capable of characterizing the estimation uncertainty. We develop a scalable stochastic variational inference algorithm for computation that can effectively deal with the multimodal posterior of period. The effectiveness of the proposed method is demonstrated through simulations and an application to observations of Miras in the Local Group galaxy M33. Without using ad hoc period correction tricks, our method achieves a distance estimate of M33 that is consistent with published work. Our method also shows superior robustness to downsampling of the light curves.

Cumulative effects of salvage logging and slash removal on erosion, soil functioning indicators and vegetation in a severely burned area in NW Spain

Post-fire salvage logging, a common practice in productive forest stands, can lead to increased soil erosion and loss of soil quality. However, further field research is required to confirm and clarify these effects. This study was conducted in NW Spain, in productive mixed stands of P. sylvestris and P. pinaster affected in the summer of 2015 by a crown fire that caused a high level of soil burn severity. Salvage logging was carried out nine months after the fire, and the effects of logging slash retention and slash removal were compared after a further two years. The study objectives were: i) to assess soil loss in the pre-logging period and compare it with the soil losses accumulated during the two post-logging annual periods, ii) to determine whether logging slash can mitigate soil erosion after post-fire logging and iii) to compare the effects of slash cover and slash removal on soil physical, chemical and microbiological parameters and vegetation recovery and iv) to evaluate the short-term effect of salvage logging on soil functionality. Soil loss in the period between the wildfire and salvage logging (September-June) was 4.2 Mg ha−1. Soil loss was significantly lower (by 2.4 times) in the post-salvage logging period than in the pre-logging period. Slash cover significantly reduced soil loss (2.6 compared with 1.7 Mg ha−1), with no detrimental effect on soil properties and no effect on the recovery of natural vegetation cover.Around three years after a wildfire followed by logging, while soil physical parameters analyzed did not show values reflecting a severe impact, symptoms of delayed recovery of soil microbial and enzymatic attributes were detected. Our study also revealed a contrasting difference between the slow recovery of the soil physical and microbial properties and the rapid recovery of the vegetation. Further research will be needed to clarify that response.

Extended log periodic approach in analysing local critical behaviour–case study for Covid -19 spread in Albania.

Log-periodic (LP) functions of the general form y = y 0 + A(t − t c ) m (1 + Bcos(ω ∗ log(t − t c ) + ϕ 1)) have been demonstrated effective in the analysis of the processes characterized by the discrete scale of invariance (DSI) structure and also self-organization behaviour. If other self-organization processes opposing or supporting the principal activity would be present, a multilevel DSI structure is expected to develop and the resulting dynamics would depart from the log-periodic shape. When discussing the processes characterising the daily new positive records for the COVID-19 cases in the country (Albania) we have identified the elements that are responsible to generate modified LP behaviour. The new records that initially represented simply the findings of the state laboratories, are modified each successive days by the pressure for more tests form anxious individuals and other effects which produce a herding behaviour which emergence a LP dynamics. Meanwhile, the reactive behaviour aiming to oppose undesired occurrence would generate additional LP sub-processes that can be trapped by a modified LP function of the form y = y 0 + A(t − t c ) m + B(t − t c ) m cos (ω ∗ log(t − t c ) + ϕ 1) + C cos( (ω − ω 1 ) log(t − t c ) + ϕ 2)+D(t − t c ) m cos ((ω + ω 1) log(t − t c ) + ϕ 3). During the period of the self-organization behaviour the process is highly nonlinear and therefore the classical models (SIR) based on the mean field assumption and the corresponding ODE equations are not effective to represent the system dynamics. In our case the LP fit to the Covid-19 new cases data series, has challenged the ODE models for the time interval of initial appearance of the positive cases in the country (as of 2 March 2020) up to 3 month later. Also, the LP function has predicated the multiphase waving behaviour and we have forecasted two peak, each of them weeks before recurrence, respectively at 28 April and 10-12 June. Those peaks have been confirmed later within 2 days uncertainty. It resulted that the first regime have been succeeded by another new self-organization regime due to drastic condition changes as result of the socio-economic opening which started in the end of the May 2020. As result, the new regime is juxtaposed over the old one and the LP dynamics remained characteristic and another critical time has appeared. The new critical time has been reproduced with good certainty (1 August) and also the magnitude of the new cases. We observed that our empirical LP function is effective in the describing long term dynamics whereas local techniques involving neural networks approaches have reproduced very well the new cases after the first regime. We concluded that after identification of the LP regimes, we can adopt successfully short time forecasting for new occurrence when working away from the critical time identified by the first method.

Прогнозная модель воздействия трелевочной системы на лесной почвогрунт в сложных сезонно-климатических условиях

In the Russian Federation logging operations are traditionally carried out in winter. This is due to the predominance of areas with swamped and water-logged (class III and IV) soils in the forest fund, where work of forestry equipment is difficult, and sometimes impossible in the warm season. The work of logging companies in the forests of the cryolithozone, characterized by a sharply continental climate, with severe frosts in winter, is hampered by the fact that forest machines are not recommended to operate at temperatures below –40 °C due to the high probability of breaking of metal structures and hydraulic system. At the same time, in the warm season, most of the cutting areas on cryosolic soils become difficult to pass for heavy forest machines. It turns out that the convenient period for logging in the forests of the cryolithozone is quite small. This results in the need of work in the so-called off-season period, when the air temperature becomes positive, and the thawing processes of the soil top layer begin. The same applies to the logging companies not operating in the conditions of cryosolic soils, for instance, in the Leningrad, Novgorod, Pskov, Vologda regions, etc. The observed climate warming has led to a significant reduction in the sustained period of winter logging. Frequent temperature transitions around 0 °C in winter, autumn and spring necessitate to work during the off-season too, while cutting areas thaw. In bad seasonal and climatic conditions, which primarily include off-season periods in general and permafrost in particular, it is very difficult to take into account in mathematical models features of soil freezing and thawing and their effect on the destruction nature. The article shows that the development of long-term predictive models of indicators of cyclic interaction between the skidding system and forest soil in adverse climatic conditions of off-season logging operations in order to improve their reliability requires rapid adjustment of the calculated parameters based on the actual experimental data at a given step of the cycles.

The Changing Disturbance Regime in Eastern Canadian Mixed Forests During the 20th Century

How strong was the anthropogenic imprint in the disturbance regime of eastern Canadian mixed forests during the 20th century? And how did it alter the tree species composition? To answer these questions, we reconstructed the 20th century anthropogenic disturbance regime and analyzed its impact on modern forest composition using historical and modern forest inventory and map data. Between 1895 and 2005, an equivalent of 144% of the study area has been logged and 19% burned. The logging rotation period has shortened from 152 years in 1895–1935 to 47 years in 1965–2005, due to increased industrial capacity. The fire rotation period decreased from 1668 years in 1895–1925 to 200 years during the peak of human settlement (1925–1955), and then increased to 2925 years in 1955–2005. The geographical progression of anthropogenic disturbances in the landscape has reflected the socio-economic context. During the 20th century, logging moved inland from the margins of the main water courses, reflecting the shift in wood transport from log driving on rivers to the densification of the road network in the second half of the 20th century. Most fires were located at low altitude, close to private lands suggesting ignitions from anthropogenic origins. Fire prone species (poplars) are mostly found within burned areas. Despite these disturbances, forest composition remained relatively stable, suggesting resilience of regional forest ecosystems.

Quantifying the Effect of Machine Translation in a High-Quality Human Translation Production Process

This paper studies the impact of machine translation (MT) on the translation workflow at the Directorate-General for Translation (DGT), focusing on two language pairs and two MT paradigms: English-into-French with statistical MT and English-into-Finnish with neural MT. We collected data from 20 professional translators at DGT while they carried out real translation tasks in normal working conditions. The participants enabled/disabled MT for half of the segments in each document. They filled in a survey at the end of the logging period. We measured the productivity gains (or losses) resulting from the use of MT and examined the relationship between technical effort and temporal effort. The results show that while the usage of MT leads to productivity gains on average, this is not the case for all translators. Moreover, the two technical effort indicators used in this study show weak correlations with post-editing time. The translators’ perception of their speed gains was more or less in line with the actual results. Reduction of typing effort is the most frequently mentioned reason why participants preferred working with MT, but also the psychological benefits of not having to start from scratch were often mentioned.

Dynamic prediction of uneven-aged natural forest for yield of Pinus taiwanensis using joint modelling.

In order to determine the stand age in the uneven-aged natural forest, a dynamic prediction model of stand volume and biomass was established in this study. In the model, the site quality grade was used as the dumb variable and the interval was used as the independent variable. In addition, the parameters of the model were estimated using immune evolutionary algorithm. The model was verified with the field data and the result revealed that the model had high accuracy. On this basis, the dynamic prediction model for forest stock was applied to evaluate the asset evaluation of uneven-aged natural forest and estimate carbon storage/sink potential of forest biomass. The selective logging period of the forest in the four plots was determined at the selective logging intensity of 40%. However, at the selective logging intensity of 40%, the forest ecological environment was suffered from the adverse effect to a certain extent from the perspective of scientific management, diversity of species, etc. Based on the comprehensive consideration of all the factors, it is recommended to set the selective cutting intensity in the range of 30 to 35%. The results can provide technical support for the application of selective logging income method in asset evaluation. Therefore, the results of this study have theoretical significance and practical application value in dynamic prediction of forest resources, asset evaluation and management, decision-making, etc.

Estimating Price Dynamics in the Aftermath of Forest Disturbances: The Biscuit Fire in Southwest Oregon

Abstract Catastrophic forest disturbances, such as wildfires, insect outbreaks, and hurricanes, have become more frequent in recent decades. Such disturbances can create supply disruptions in regional timber markets, with potentially significant short-run and long-run price effects. We review the time-series intervention models that have been used to analyze the impacts of forest disturbances. We apply the intervention models to investigate the market effects of the Biscuit Fire that burned nearly 500,000 acres (202,000 hectares) of forest land in southwest Oregon in 2002, thus creating an unexpected supply shock in the regional timber markets. Most of the burned area was located on federal lands. Although almost two billion board feet were available for harvesting by some estimates, the salvage logging on public lands after the Biscuit Fire amounted to 60 million board feet by the end of 2005. We use a univariate and reduced-form model to estimate the effect of the Biscuit Fire on regional Douglas-fir log markets. We find that the fire did not cause immediate price effects; however, we detect positive effects during the salvage logging period in some of the markets, whereas a negative long-run effect has persisted since the salvage logging period was completed.

In Colombia the Eurasian fungus Amanita muscaria is expanding its range into native, tropical Quercus humboldtii forests

ABSTRACTTo meet a global demand for timber, tree plantations were established in South America during the first half of the 20th century. Extensive plantings of non-native species now are found in Brazil, Chile, Argentina, and Uruguay. In Colombia, miscellaneous plantations were established in the 1950s, during a period of intensive local logging, when policies to limit deforestation in native Quercus humboldtii forests were established. One unforeseen consequence of planting non-native trees was the simultaneous introduction and subsequent persistence of ectomycorrhizal fungi. We sought to document the origins and spread of the introduced Amanita muscaria found in Colombian plantations of the Mexican species Pinus patula, North American species P. taeda, and Australian species Acacia melanoxylon and Eucalyptus globulus. In Colombia, Amanita muscaria is establishing a novel association with native Q. humboldtii and has spread to local Q. humboldtii forests. According to a Bayesian phylogeny and haplotype analysis based on the nuclear rDNA internal transcribed spacer region ITS1-5.8-ITS2 (ITS barcode), A. muscaria individuals found in four exotic plant species, and those colonizing Q. humboldtii roots, have a Eurasian origin and belong to two Eurasian haplotypes. This is the first time the spread of an introduced mutualist fungus into native Colombian Q. humboldtii forests is reported. To arrest its spread, we suggest the use of local inocula made up of native fungi, instead of inocula of introduced fungi.

Premature mortality projections in the USA through 2030: a modelling study

Although life expectancy has been projected to increase across high-income countries, gains for the USA are anticipated to be among the smallest, and overall US death rates actually increased from 2014 to 2015, with divergence for specific US populations. Therefore, projecting future premature mortality is essential for clinical and public health service planning, curbing rapidly increasing causes of death, and sustaining progress in declining causes of death. We aimed to project premature mortality (here defined as deaths of individuals aged 25-64 years) trends through 2030, and to estimate the total number of projected deaths, the projected number of potential years of life lost due to premature mortality, and the effect of reducing projected accidental death rates by 2% per year. We obtained death certificate data for the US population aged 25-64 years for 1990-2015 from the US Centers for Disease Control and Prevention (CDC) National Center for Health Statistics. We obtained US mortality data for 2016 for non-American Indian or Alaska native groups from CDC WONDER; data for 2016 were not available for American Indians or Alaska natives. Our analysis focused on all-cause premature mortality and the commonest causes of premature death (cancer, heart disease, accidents, suicide, and chronic liver disease or cirrhosis) among white, black, Hispanic, Asian or Pacific islanders, and American Indian or Alaska native men and women. We estimated age-standardised premature mortality and corresponding annual percentage changes for 2017-30 by sex and race or ethnic origin by use of age-period-cohort forecasting models. We also did a sensitivity analysis projecting future mortality from cross-sectional mortality and a JoinPoint of the (log) period rate ratio curve. We calculated absolute death counts by use of corresponding age-specific and year-specific US census population projections, and estimated years of potential life lost. During 2017-30, all-cause deaths are projected to increase among white women and American Indians or Alaska natives, resulting in 239 700 excess premature deaths relative to 2017 rates (a 10% increase). Mortality declines in white men and black, Hispanic, and Asian or Pacific islander men and women will result in 945 900 fewer deaths (a 14% reduction). Cancer mortality rates are projected to decline among white, black, Hispanic, and Asian or Pacific islander women and men, with the largest declines among black women (age-standardised premature mortality rate 2016: 104·5 deaths per 100 000 woman-years; 2030: 77·1 per 100 000 woman-years) and men (2016: 116·8 per 100 000 man-years; 2030: 81·6 per 100 000 man-years). Heart disease death rates are projected to increase in American Indian or Alaska native men (2015: 150·9 per 100 000 man-years; 2030: 175·9 per 100 000 man-years) and decline in other groups, albeit only slightly in white (2016: 35·6 per 100 000 woman-years; 2030: 31·1 per 100 000 woman-years) and American Indian or Alaska native women (2015: 64·4 per 100 000 woman-years; 2030: 62·8 per 100 000 woman-years). Accidental death rates are projected to increase in all US populations except Asian or Pacific islander women, and will increase most rapidly among white women (2030: 60·5 per 100 000 woman-years) and men (2030: 101·9 per 100 000 man-years) and American Indian or Alaska native women (2030: 97·5 per 100 000 woman-years) and men (2030: 298·7 per 100 000 man-years). Suicide rates are projected to increase for all groups, and chronic liver disease and cirrhosis deaths are projected to increase for all groups except black men. A 2% per year reduction in projected accidental deaths would eliminate an estimated 178 700 deaths during 2017-30. To reduce future premature mortality, effective interventions are needed to address rapidly rising mortality rates due to accidents, suicides, and chronic liver disease and cirrhosis. National Cancer Institute Intramural Research Program.

Cyclic heliothermal behaviour of the shallow, hypersaline Lake Hayward, Western Australia

Lake Hayward is one of only about 30 hypersaline lakes worldwide that is meromictic and heliothermal and as such behaves as a natural salt gradient solar pond. Lake Hayward acts as a local groundwater sink, resulting in seasonally variable hypersaline lake water with total dissolved solids (TDS) in the upper layer (mixolimnion) ranging between 56 kg m−3 and 207 kg m−3 and the deeper layer (monimolimnion) from 153 kg m−3 to 211 kg m−3. This is up to six times the salinity of seawater and thus has the highest salinity of all eleven lakes in the Yalgorup National Park lake system. A program of continuously recorded water temperature profiles has shown that salinity stratification initiated by direct rainfall onto the lake’s surface and local runoff into the lake results in the onset of heliothermal conditions within hours of rainfall onset.The lake alternates between being fully mixed and becoming thermally and chemically stratified several times during the annual cycle, with the longest extended periods of heliothermal behaviour lasting 23 and 22 weeks in the winters of 1992 and 1993 respectively. The objective was to quantify the heat budgets of the cyclical heliothermal behaviour of Lake Hayward.During the period of temperature profile logging, the maximum recorded temperature of the monimolimnion was 42.6 °C at which time the temperature of the mixolimnion was 29.4 °C.The heat budget of two closed heliothermal cycles initiated by two rainfall events of 50 mm and 52 mm in 1993 were analysed. The cycles prevailed for 11 and 20 days respectively and the heat budget showed net heat accumulations of 34.2 MJ m−3 and 15.4 MJ m−3, respectively. The corresponding efficiencies of lake heat gain to incident solar energy were 0.17 and 0.18 respectively. Typically, artificial salinity gradient solar ponds (SGSP) have a solar radiation capture efficiencies ranging from 0.10 up to 0.30. Results from Lake Hayward have implications for comparative biogeochemistry and its characteristics should aid in identification of other hitherto unknown heliothermal lakes.

Wideband and Efficient Slot Cavity Backing for Unidirectional Log-Periodic Antenna

A slot cavity backing for unidirectional log-periodic (LP) antennas is proposed. Bowtie slot is etched on the bottom of a cavity to mitigate the degradation in impedance match at low frequency band of an LP antenna. The impedance match is further improved, and backward radiation is suppressed by resistively loading the slot. For conformal mounting of the antenna, an additional cavity with ferrite loading is attached to the bottom of the slot layer. Additionally, the slot termination is reengineered to enable recycling of the coupled power into the slot. The unidirectional LP antenna with the proposed cavity backing is prototyped and measured. The proposed antenna achieves VSWR below 3:1 from 0.5 to 5 GHz and below 2.5:1 from 0.64 to 5 GHz. The gain is higher than −2.9 dBi over 0.5 to 5 GHz (above 5 dBi from 1.5 GHz). Considerable improvement in gain and efficiency compared to a conventional ferrite-loaded cavity is demonstrated, while recycling option if exercised may further improve the system efficiency.