Detection of elliptical polarization and mode splitting in discrete Schumann resonance excitations

Elliptical polarization and mode splitting have been detected in the magnetic component of discrete, well defined Schumann resonance excitations. These ELF excitations, which are large electromagnetic transients of approximately l s duration, are called Q-bursts and typically occur every few minutes. They are believed to be the signature of the impulsive excitation of the Earth-ionosphere cavity by ultra-large lightning currents. In this paper the magnetic polarization and spectral characteristics of four large Q-bursts are examined in detail using a new analysis technique. Two events display right-hand polarization and two display left-hand polarization. The theoretical polarization properties of the central and side multiplets of the Schumann resonances are used to define a local orthogonal coordinate system in the measurement frame in which these components may be separated. Maximum entropy spectrums computed separately for what are identified to be the central and side multiplets in this coordinate system show distinctly different eigenfrequencies for the lowest mode near 7.5 Hz. For the limited number of cases examined the magnitude of the line splitting detected using this technique is roughly 1.4–1.8 Hz, larger by nearly a factor of two than theoretical or observed values of the splitting previously reported. The frequencies of the side multiplets may lie either above or below the frequency of the central multiplet.     

Accelerating the convergence of the zonal harmonic series representation in the Schumann resonance problem

A formula of Nickolaenko and Rabinowitz for the calculation of Legendre's function of the first kind of complex degree is corrected. A numerical test of the corrected formula is presented.     

Double structure of ionospheric conductivity in the midnight auroral oval during a substorm

Measurements of precipitating particles on board DMSP F7 spacecraft are used to analyze the distribution of ionospheric conductance in the midnight auroral zone during substorms. The distribution is compared with the meridional profile of ionospheric currents calculated from magnetic data from the Kara meridional chain. Two regions of high Hall conductance are found; one of them is the traditional auroral zone, at latitudes 64–68°, and the other is a narrow band at latitudes 70–73°. The position of high conductance zones is in agreement with the location of the intense westward currents. The accelerated particle population is typical of electrons E_e > 5 keV in the high conductance region.     

Calculation of ionospheric effects due to acoustic radiation from an underground nuclear explosion

Within the framework of the ionospheric detection of underground nuclear tests, we have developed an analytic computing technique for the acoustic effect of a confined nuclear explosion on upper layers of the Earth's atmosphere. The relationship (32) is obtained, which relates the nuclear test parameters (depth, explosion yield, and mechanical properties of the rock) to the vertical displacement of the ionosphere produced by the shock wave over the explosion's epicentre. It is also shown that most of the acoustic energy produced by a confined underground nuclear explosion escapes upward, with only a small fraction being captured by the atmospheric waveguide.     

Weak nonlinear theory of the ionospheric response to atmospheric gravity waves in the F-region

The nonlinear ionospheric response to atmospheric gravity waves is studied in an approximate fashion using a new approach. The concept of nonlinear travelling ionospheric disturbances (TIDs) is outlined, and the nonlinear behaviour of atmospheric gravity waves is calculated. A principal result is that harmonics are generated which cause the wave velocity perturbation to deform. The ionospheric response is investigated by solving the continuity equation for ionization in the F-region. The distortion of the TIDs waveform produced by the nonlinear interactions is depicted. The nonlinear TIDs depart seriously from a cosinusoidal wave described by previous linear TID theory. The distorted TIDs appear as ‘sharp peak’ and ‘sawtooth’ waveform shapes. The ‘peaks’ can be upward or downward, and the ‘sawteeth’ forward or backward, depending on the wave parameters. The nonlinearly distorted TIDs show a good agreement with various observed ionospheric irregularities produced by atmospheric gravity waves.     

Some effects of geomagnetic activity on spread-F occurrence and ionospheric height variations in equatorial regions

AE indices have been used to investigate, at times of increased geomagnetic activity, the possibility of significant changes to both spread-F occurerence and h′F values for 3 stations in equatorial latitudes. The investigation covered a sunspot minimum period. Furthermore, data for each of these parameters have been considered for both a pre-midnight period (interval A) and a post-midnight period (interval B). The use of the AE indices at 12 different times at 2 h intervals allows the measurement of the delay times, after increased geomagnetic activity, of any significant changes in the parameters being investigated.The results show that for interval A significant suppressions of spread-F occurrence are recorded at delay times of approximately 3 h and 9 h. These delays correspond to enhanced geomagnetic activity at local times of 1800 and 1200, respectively. Also, for interval A the h′F variations suggest that h′F is suppressed at times of spread-F suppression. For interval B spread-F occurrence seems to be controlled by two opposing effects. For several hours after enhanced geomagnetic activity spread-F occurrence increases significantly, followed by a sharp decline culminating in suppressed occurrence, again related to increased geomagnetic activity at 1800 local time for the maximum effect. Also, for interval B h′F values lift abruptly a few hours after enhanced geomagnetic activity, followed by a gradual decline when delays of up to 20 h are considered. Further work on these delays may allow reliable short-term forecasting of some ionospheric behaviour in equatorial regions.     

Vertical profiles of electrical conductivity in the lowermost part of the turbulent boundary layer over flat ground

Results of experimental investigations and a theoretical estimation of the polar conductivity profiles in the turbulent surface layer over flat ground are discussed. The results presented are evidence for the occurrence of the steady electrode effect over land. By reducing the number of factors which influence the vertical conductivity profile and applying a special measuring technique, it has been possible to obtain steady profiles.The experimental results are in good agreement with the hypothesis of a turbulent electrode effect in the boundary of strong turbulent mixing. The agreement implies the confirmation of the relation between the surface wind, the electrical conductivity and the thickness of the electrode-effect layer.     

The effects of the resonance broadening of Farley-Buneman waves on electron dynamics and heating in the auroral E-region

Several theories have now been developed which deal with the saturation mechanism of the Farley-Buneman instability and also the heating effect of Farley-Buneman waves on E-region electrons. Various related phenomena, such as anomalous collisions, anomalous cross-field diffusion and non-zero aspect-angle propagation have been treated. In this paper, it is demonstrated how several of these features may be included in a single resonance broadening formalism. Using this approach, the effects of Farley-Buneman waves on the heating and dynamics of background ionospheric electrons is discussed. In addition the effects of anomalous parallel diffusion in the context of E-region Farley-Buneman waves is treated for the first time.     

Endorheic currents in ecology: an example of the effects from scientific specialization and interdisciplinary isolation

ABSTRACT

Mainstream ecological thought is explored in three sections: (i) Epistemological traits. Given the typical scientific development and the necessity of preserving our intellectual heritage, the conservatism outlined in (i) is cyclical, so its stages are graphically summarized. (ii) Methodological benchmarks antithetically derived from (i), in order to get faster advancement consistent with the growing environmental challenges which spur ecological development. (iii) The renaissance of an old paradigm. This section exposes the misunderstanding of the physical concept of equilibrium by the mainstream ecological thought; this explains its current state. Consequently, section (iii) also summarizes the evolution of a recent set of proposals (organic biophysics of ecosystems) that rescues the foundational paradigm of ecosystem ecology based on physics, neglected by the mainstream thought before producing its most valuable results. We highlight that the main problems emerge from the weakness of integration between ecology, physics and epistemology, and spurious links between ecology and neoclassical economics.     

Ancient-DNA reveals an Asian type of Mycobacterium leprae in medieval Scandinavia

Leprosy is a chronic infection of the skin and peripheral nerves caused by the pathogen Mycobacterium leprae. Its impact on human populations and societies of the past as well as its phylogeographic patterns around the world – at least in modern times – has been well documented. This slow growing bacterium has been shown to exist in distinct ‘SNP types’ that occur in relatively defined parts of the globe. The routes that the disease followed in the past are, however, still uncertain. This study of ancient-DNA typing of archaeological human remains from Sweden dated to early Medieval times provides genetic evidence that a transmission of M. leprae ‘SNP subtype’ 2G – found mainly in Asia – took or had already taken place at that time from the Middle East to Scandinavia. This finding is unique in the history of leprosy in Europe. All human specimens from this continent – both modern and ancient – that have been tested to date showed that the one responsible for the infection strains of M. leprae belong to ‘SNP type’ 3, whereas our results show that there were some European populations that were hosts to bacteria representing ‘SNP type’ 2 of the species as well.     

太仓半泾河古船难溶盐脱除效果研究

太仓半泾河古船是近海河道出土的古船,在保护修复工作开展前期,需采取脱盐处理。为全面了解船木含盐情况,针对不同部位不同树种船木样品中的盐分种类与含量进行检测与分析,结果表明:船木所含的难溶盐以硫铁化合物为代表,部分含有FeS_2。船木颜色发黑与船材中的铁离子有关,铁离子主要来源于船上的铁钉,采用金属螯合剂发生螯合反应进行脱除。通过对比研究EDTAHO(EDTA-2Na和H_2O_2复配试剂)、EDTA-2Na和NaH_2PO_4·2H_2O浸泡法的脱盐效果,发现1 000 mL体积分数0.4%中性EDTA-2Na溶液脱盐综合效果最好,44 d内进行两次脱盐可以把铁离子的质量浓度控制在1 mg/L内。通过便携式色差仪检测脱盐后样品的L、a、b值计算色差ΔE接近健康材,且对综纤维素和木质素的损伤最小。最终选用EDTA-2Na作为太仓古船的难溶盐脱除试剂。本研究结果可为后续保存工作提供有利条件。     

Towards an Inclusive Archaeology in Jerusalem: The Case of Silwan/The City of David

Abstract

The village of Silwan, in East Jerusalem, contains the remains of most ancient Jerusalem, often termed “The City of David”. In recent years the excavation and presentation of the archaeology of Silwan has been placed in the hands of a Jewish settler non-governmental organization. Their incorporation of this site into the Jewish-Israeli narrative is multifaceted — mixing religious nationalism with theme-park tourism. As a result, conflict with local Palestinians occurs at the very basic level of existence, where the past is used to disenfranchise and displace people in the present. The volatile mix of history, religion and politics in the City of David/Silwan threatens any future reconciliation in Jerusalem, which must be based on the empowerment of local people and the adoption of a proactive inclusive archaeological stance in which the many voices of the past are heard.     

Mycobacterium leprae genotype amplified from an archaeological case of lepromatous leprosy in Central Asia

We have amplified Mycobacterium leprae DNA from the skeleton of an adult human female exhibiting signs of lepromatous leprosy (LL). The remains were excavated from the site of Devkesken 6 on the Ustyurt plateau of Uzbekistan and date to between the 1st and 4th centuries AD. Recovered DNA was fragmented but of sufficient quality and quantity to allow a series of biomolecular genotyping methods to be applied. These methods included variable nucleotide tandem repeat (VNTR) typing of two microsatellite and one minisatellite regions and also single-nucleotide polymorphism (SNP) typing for nine informative loci.Genotyping showed that the causative strain of M. leprae exhibited a SNP-type 3 profile, characteristic of cases associated geographically with Europe and North Africa. Further SNP sub-typing was performed and the data obtained from the Uzbek leper was compared with the same loci amplified from a case of LL recovered from Blackfriars, Ipswich, UK dating to between the 13th and 16th centuries AD. Unique group 3 subtypes were found in both the Uzbek case and Ipswich 1914. These appear to be ancestral to recent type 3 strains. Mycolic acid analysis confirmed the presence of M. leprae in the Uzbek samples. Phylogenetically informative SNPs and other polymorphic loci will contribute to the study of human migrations, as well as the origin and spread of leprosy.     

The 'Harefield/Anzac Bond': a study of thanksgiving and remembrance in an English village

Abstract

This article arises out of wider work on the impact and experiences of World War I. It deals with the care offered to Australian soldiers wounded in battle and subsequently sent to England to recuperate. Much of this care was offered in hospitals specifically for Australian soldiers and the article deals with one particular hospital, Harefield. The relationships between the community, the hospital and the individual soldiers are investigated and enduring relationships of respect and care are identified. These relationships are shown to stretch to the present day.     

Ascertaining an agent: using tooth pit data to determine the carnivore/s responsible for predation in cases of suspected big cat kills in an upland area of Britain

The identification of the involvement of a particular carnivore in the modification of bone assemblages concerns a number of fields of research including archaeological and palaeontological enquiry. Taphonomy provides a methodology by which bone assemblages can be analysed and interpreted and this is more often undertaken with archaeological or palaeontological assemblages. A taphonomic analysis is undertaken here in order to determine the perpetrator of predation attacks on domestic stock from a modern-day setting. Recently reported techniques using tooth marks preserved on bone surfaces made by known carnivores are successful at determining some class sizes of predators and are used here to determine the perpetrator(s). Although a class size of carnivore is readily identified by this methodology, a particular carnivore taxon is not. Tooth morphology and dental configuration are reported here as better criteria for identifying a particular taphonomic agent. Tooth pit dimensions are used here to identify the class size of carnivores involved, and tooth morphology and cusp spacing to suggest a medium sized felid and fox as taphonomic agents. The identification of the medium-sized felid may support observations and reports of alleged “big” cat kills in the area. The study has important implications for the interpretation of fossil sites where felids may have been involved in the modification of animal carcasses but are archaeologically invisible in terms of their fossil remains.     

Immunological evidence of Plasmodium falciparum infection in an Egyptian child mummy from the Early Dynastic Period

A 15–18 months old child mummy, presently housed in Turin's Museum of Anthropology, was discovered in Gebelein (Upper Egypt) during excavations carried out by the Missione Archeologica Italiana, most likely in 1914.     

Using airborne small-footprint laser scanner data for detection of cultural remains in forests: an experimental study of the effects of pulse density and DTM smoothing

Cultural remains are laborious to register by means of field surveys. Thus, in recent years several trials using remote sensing data to detect cultural remains have been carried out. The most promising remote sensing technique for such purposes is airborne laser scanning (ALS) from which digital terrain models (DTM) that enable visual interpretations of anomalies on the ground are generated. Although it has been documented previously that ALS is a powerful data source for detection of cultural remains, it has not yet been carried out studies that focus on the effects of the point density of the ALS data and properties of the subsequent generation of the DTM on the detection success of cultural remains. Thus, this study aimed at analyzing these effects by letting four experienced archeologists interpret DTMs generated from ALS data with point densities of 1 p m⁻², 5 p m⁻², and 10 p m⁻², each with three different levels of DTM smoothing. The experiment was conducted according to a randomized complete block design and the analyses were carried out using analysis of variance. The results showed that there was a significant improvement in the detection success when the point density was increased from 1 p m⁻² to 5 p m⁻². There were also some improvements when increasing the point density further to 10 p m⁻², but they were less pronounced. Furthermore, the results showed that the DTM smoothing did not have any significant effect on the detection success.