Regressive Stage Research Articles

A framework for Late Quaternary lake-level fluctuations in Lake Karakul, eastern Pamir, focusing on lake–glacier landform interaction

This paper presents a framework for Late Quaternary lake-level fluctuation in the closed-basin lake “Lake Karakul” (eastern Pamir) on the basis of the stereoscopic observation of remote sensing data, field mapping and relative dating. The palaeoshorelines (approximately 60 in number) observed around the Lake Karakul can be classified into four groups: H Shorelines, M Shorelines, L Shorelines and LL Shorelines (in the descending order of height). The highest level of each of the above palaeoshoreline groups is 205 m, 85 m, 35 m and 10 m above the present lake level (3915 m asl). From the glacial landform developments and related valley-fill sedimentation patterns around the threshold of the present basin closure, the lake-level fluctuation defined by these palaeoshoreline groups was found to be a consequence of the water balance change within the closed basin. With respect to the timing of the palaeolake highstands, the relationship between lacustrine terraces and terminal moraines suggests the synchroneity of the highest stand of each palaeolake with the corresponding maximum glacier advance. The tentative chronology of the lake-level fluctuation was established from the synthesis of the style of geomorphic development and related glaciation, relative dating on moraine gravels, and the correlations to established glacial histories in and around the Pamir. The periods of the palaeolake highstands indicated by H, M, L and LL shorelines seem to be correlated with the antepenultimate glacial (MIS 8), penultimate glacial (MIS 6), early last glacial (MIS 4) and the late last glacial (MIS 2) periods, respectively. Based on this chronology, each of the 60 palaeoshorelines are expected to show stable lake surfaces during lake regressive stages toward the terminations from the glacial maxima of MIS 8, 6, 4 and 2. Given that the distinct landforms of each palaeoshoreline group were formed in association with the predominant stagnation or small re-transgression of the palaeolake, the short-term cooling and/or wetter episodes, which turned positive lake hydrologic balances from negative ones, were superimposed on the major palaeoclimate changes during the glacial termination periods.

Poliosis of Eyelashes as an Unusual Sign of a Halo Nevus

A 39-year-old man with poliosis of his lower eyelid lashes visited our clinic. He reported that his symptoms began with a few central lashes and then spread along the adjacent lashes during the ensuing 2 weeks. A pigmented nevus, approximately 4 mm in diameter, was identified just above the white lashes without surrounding skin depigmentation. No specific findings were identified with regard to the patient's general health or serologic and radiologic testing. Excisional biopsy of the pigmented nevus was performed. On histopathologic examination, infiltration of the dermis by numerous lymphocytes and melanophages was observed. The poliosis was ultimately diagnosed as a presenting sign of the halo phenomenon in the regressive stage of a melanocytic nevus.

Native elements in rocks of the banded iron formation, Kola Peninsula

Eleven native minerals and intermetallic alloys were identified in rocks of the banded iron formation (BIF) in the Kola Peninsula: copper, silver, gold, electrum, auricupride, cuproauride, tetraauricupride, bismuth, sulfur, tellurium, and graphite. Graphite is a common mineral of sulfide-bearing BIF and gneiss. Sulfur occurs in supergene-altered sulfide-bearing BIFs together with Fe- and Ca-sulfates. Gold of low fineness (electrum) in association with electrum, acanthite, auricupride, volynskite, hessite, cervelleite, pavonite, petzite, and bismuth is related to the areas of hydrothermally altered skarnoids with greenalite, chamosite, aegirine, and Na-Ca amphibole. Redeposited gold of high fineness associated with auricupride, hessite, silver, electrum, kostovite, cuproauride, tetraauricupride, and sperrylite occurs in low-temperature zonal hydrothermal segregations hosted in aluminous gneiss and which formed under the effect of alkalized, highly siliceous solutions at the regressive stage of BIF metamorphism.

Paroniceratinae (Ammonoidea, Hildoceratidae) del Toarciense en las Cordilleras Ibérica y Cantábrica (España)

The Paroniceratinae constitute a group widely recorded in the Tethys realm. However, they represent alone a small part, less than 1%, of the ammonoidea obtained in Toarcian sediments from the regions located at the east of the Iberian Plateau (Iberian Range). The values are yet smaller in the northern regions (Cantabrian Range) and in the west (Portugal), and show a sporadic presence in the Betics Ranges. In this study, the biostratigraphical distribution and the biochronostratigraphical position of the recorded species in the more representative expanded sections of Spain are checked and compared with those of other areas of the NW Europe bioprovinces and of the Tethys. The obtained specimens from Frechiella: F. subcarinata (Young and Bird), F. helenae Renz, F. venantii (Catullo), F. kammerkarensis (Stolley) and F. cf. octaviae Renz are described and figured, all of them proceeding from sediments of the Bifrons Zone in the Iberian Range, as well as those of Paroniceras: P. sternale (d’Orbigny) and P. helveticum Renz, and Oxyparoniceras: O. ( O.) cf. telemachi (Renz), O. ( O.) buckmani (Bonarelli), O. ( N.) cf. undulosum (Monestier), O. ( N.) cf. morbiense (Renz) and O. ( N.) cf. brocardi Rulleau, Bécaud and Neige, proceeding from sediments of the interval between the Bifrons Zone (Semipolitum Subzone) and the Insigne Zone (Insigne Subzone), in the Iberian and Cantabrian Ranges. The Frechiella and Oxyparoniceras species are developed and recorded in the Iberian Plateau margins during the Bifrons Zone and the Insigne Zone, respectively, during the same intervals than the transgressive maxima of the LJ3 and LJ4 second order cycles recognized in all the studied area, while Paroniceras species make it during the Variabilis Zone, that concur with the final regressive stage of the LJ3 cycle.

Unusual concentration of Early Albian arthropod-bearing amber in the Basque-Cantabrian Basi (El Soplao, Cantabria, Northern Spain): Palaeoenvironmental and palaeobiological implications

The El Soplao site is a recently-discovered Early Albian locality of the Basque-Cantabrian Basin (northern Spain) that has yielded a number of amber pieces with abundant bioinclusions. The amber-bearing deposit occurs in a non-marine to transitional marine siliciclastic unit (Las Penosas Formation) that is interleaved within a regressive-transgressive, carbonate-dominated Lower Aptian-Upper Albian marine sequence. The Las Penosas Formation corresponds to the regressive stage of this sequence and in its turn it splits into two smaller regressive-transgressive cycles. The coal and amber-bearing deposits occur in deltaic-estuarine environments developed during the maximum regressive episodes of these smaller regressive-transgressive cycles. The El Soplao amber shows Fourier Transform Infrared Spectroscopy spectra similar to other Spanish Cretaceous ambers and it is characterized by the profusion of sub-aerial, stalactite-like flows. Well-preserved plant cuticles assigned to the conifer genera Frenelopsis and Mirovia are abundant in the beds associated with amber. Leaves of the ginkgoalean genera Nehvizdya and Pseudotorellia also occur occasionally. Bioinclusions mainly consist of fossil insects of the orders Blattaria, Hemiptera, Thysanoptera, Raphidioptera, Neuroptera, Coleoptera, Hymenoptera and Diptera, although some spiders and spider webs have been observed as well. Some insects belong to groups scarce in the fossil record, such as a new morphotype of the wasp Archaeromma (of the family Mymarommatidae) and the biting midge Lebanoculicoides (of the monogeneric subfamily Lebanoculicoidinae). This new amber locality constitutes a very significant finding that will contribute to improving the knowledge and comprehension of the Albian non-marine paleoarthropod fauna.

Canine Transmissible Venereal Tumor: A Review

Canine transmissible venereal tumor (TVT) is a commonly occurring tumor of dogs affecting both sexes. It is common in dogs which have an uncontrolled sexual behavior with incidence ranging from 2 to 43 percent of all tumors in temperate climates. The etiology appears to be cell transplant from affected to unaffected dogs. The pathogenesis, gross and microscopic findings, diagnosis, prognosis and therapies have been reviewed. Gross findings of small nodule like lesions which bleed is the most consistent clinical finding. Smears made from the tumor reveal round cells with vacuoles and mitotic figures. The tumor is many times self limiting and vincristine sulfate is currently considered the most effective therapy. The use of vincristine sulfate in male dogs must balance the potential benefits to the patient and the interest in using the animal for breeding as vincristine sulfate impairs the semen quality. Immune therapy of TVT is still to be validated for clinical use. Transmissible venereal tumor (TVT), also known as infectious sarcoma, venereal granuloma, transmissible lymphosarcoma or Sticker tumor is a benign reticuloendothelial tumor of the dog that mainly affects the external genitalia and occasionally the internal genitalia. As it is usually transmitted during coitus (Tella et al., 2004) it mainly occurs in young, sexually mature animals (Rogers, 1997).It is transplanted during coitus with intact viable cells across major histocompatibility complex (MHC) barriers within the same species (Mukaratirwa and Gruys, 2003) and even to other members of the canine family, such as foxes, coyotes and jackals (Higgins, 1966). Laboratory transplantation of TVT from one dog to other using viable cells is also possible ( Yang and Jones, 1973). TVT cells contain an abnormal number of chromosomes ranging from 57 to 64 and averaging 59, in contrast to the normal 78 of the species. Metastasis of TVT is uncommon, only occurring in puppies and immuno-compromised dogs. The uniqueness of TVT lies in the fact that this is the only proven example of a naturally occurring tumor that is transmitted as an allograft by cell transplantation, and the tumor becomes autonomous from the original host. In other words, the the tumor behaves like a parasite. This kind of tumor developed only in the dog, probably because during coitus there is extensive abrasive abrasions and bleeding of the penile mucosa and vagina, making transplantations of the tumor easy. Because TVT can be easily transplanted investigations on various aspects of tumor biology have been done to provide clues to similar phenomenon that occur in other animal and human tumors. Thus TVT has been studied extensively. A very interesting aspect that has attracted attention of TVT is the role of the host’s immune response during the progressive and regressive stages of the tumor. The capacity of immunologic response of the host has a main role in the expansion of such tumors (Cohen, 1973) with an increase in severity seen in immunologically compromised animals. In this review some known facts of TVT have been reviewed.

Vibration Response Imaging Technology in Healthy Subjects

The vibration response imaging device that we studied (VRIxp) records the intensity and location of lung sounds during a cycle of breathing. The goals of this study were to describe the characteristic features and quantitative lung data recorded by the VRIxp device from healthy asymptomatic subjects. Breath sounds (frequency range, 150-250 Hz) recorded from the backs of 151 healthy asymptomatic subjects (96 nonsmokers and 55 smokers) by the VRIxp device were mapped to create a sequence of 2D images. Three raters interpreted and scored the images for predefined static and dynamic features. In addition, quantitative lung data were analyzed for characteristic regional distributions. The readers of the images had good inter- and intrarater agreement. Image development in 93% of the evaluations showed an inspiratory and expiratory phase with a progressive and regressive stage that developed bilaterally in a vertical and synchronized manner. Characteristic image features of the maximum energy frame included a smooth, rounded, uninterrupted contour and a planar distribution, area size, and intensity that had right-left symmetry. Quantitative lung data expressed as percentages of the total (100%) vibration energy were normally distributed with mean values (+/- SD) of 55% +/- 6% for the left lung and 45% +/- 6% for the right lung. Most of the subjects with images, quantitative lung data, or both lacking these typical features were cigarette smokers or had a history of smoking (p < 0.05). Breath sounds in healthy asymptomatic subjects can be recorded and displayed in a dynamic series of images that have predictable and characteristic features recognizable and complemented by quantitative lung data. Identification and description of these characteristic image features in this study will facilitate future studies of vibration imaging in specific pulmonary diseases.

East European river runoff and Black Sea and Caspian Sea level changes as simulated within the Paleoclimate modeling intercomparison project

During the last late-Pleistocene and post-glacial epochs, the Caspian Sea fluctuated between regressive and transgressive stages. The Black Sea experienced fluctuations too, but their amplitude was smaller because they were mainly controlled by the World Ocean due to water exchange through the Bosporus Strait. In the water-budget equation, the change in storage over a time period is balanced by the sum of the inflows and outflows that occur during the time period. They can be calculated from atmospheric general circulation models (GCMs). A modeling initiative, the Palaeoclimate Modelling Intercomparison Project (PMIP), could help to resolve this question. The PMIP has focused on two slices of the past: the mid-Holocene (6ka calendar years Before Present (BP)) and the last cold event of the Late Quaternary (21ka calendar years BP). The PMIP GCM simulations indicate that changes in level are primarily influenced by changes of river runoff. Ocean precipitation and evaporation together play a minor role. At 21ka BP the estimated level lowering was ∼50 and ∼200m for the Caspian Sea and Black Sea, respectively. This lends credit to the idea of the connection between deep regressive states of Caspian Sea and Black Sea and mature stages of Late Quaternary glacial/cooling/drying planetary events.

Mass spectrometric proteomics profiles ofin vivo tumor secretomes: Capillary ultrafiltration sampling of regressive tumor masses

Identification of in vivo secreted peptides/proteins (secretomes) in tumor masses has the potential to provide important biomarkers and therapeutic targets for cancer therapy. However, limitations of existing technologies have made obtaining these secretomes for analysis extremely difficult. Here we employed an in vivo sampling technique using capillary ultrafiltration (CUF) probes to collect secretomes directly from tumor masses. Mass spectrometric proteomics approaches were then used to identify the tumor secretomes. A UV-induced skin fibrosarcoma cell line (UV-2240) was subcutaneously injected into C3H/NeH mice, resulting in tumor masses that initially progressed, then regressed and eventually eradicated. We then implanted CUF probes into tumor masses at the progressive and regressive stage. Five secreted proteins (cyclophilin-A, S100A4, profilin-1, thymosin beta 4 and 10), previously associated with tumor progression, were identified from tumor masses at the progressive stage. Five secreted proteins including three protease inhibitors (fetuin-A, alpha-1 antitrypsin 1-6, and contrapsin) were identified from tumor masses at the regressive stage. The technique involving CUF probes linked to mass spectrometric proteomics reinforces systems biology studies of cell-cell interactions and is potentially applicable to the discovery of in vivo biomarkers in human disease.

Organic petrology, mineralogy and depositional environment of the Kipra lignite seam, Maritza-West basin, Bulgaria

Abstract The aim of the present study is to provide additional information about the properties and depositional environment of the Kipra lignite seam, which was deposited during the regressive stage of development of the Maritza-West basin. Petrographical and mineralogical data, along with ash yields and sulphur contents of 24 samples from a seam profile, have been used to study the vertical variation of the depositional settings during peat accumulation and subsequent coalification. The Kipra lignite is characterized by high ash yields and sulphur contents. It formed in a rheotrophic, low-lying mire with alkaline pH value. Vegetation with low preservation potential dominated within the palaeomire. During peat formation, frequent changes of the water level controlled the depositional environment. During the deposition of units 1 and 2, high water energy caused the transportation of high amounts of inorganic material into the mire, resulting in the formation of weakly gelified mineral-rich lignite. The organic matter from units 3 and 4 is characterized by enhanced gelification, which probably reflects the decreasing energy of the system. Good positive correlation between sulphur contents and the GI values was established in units 4, indicating that the gelification of the tissues was probably mainly controlled by the bacterial activity. In contrast, the gelification of the samples from unit 3 of the Kipra seam was probably governed by the redox conditions. The organic matter deposited under relatively wet conditions, in which the thermal and oxidative destruction of the tissues, was limited. A variety of major, minor and accessory minerals are present in Maritza-West lignite. The mineral composition is dominated mainly by pyrite, gypsum and calcite, and to a lesser extent limonite, quartz, kaolinite, montmorillonite, illite, chlorite and plagioclase. Jarosite, hematite, halloysite, mica, K-feldspar, aragonite, siderite, and dolomite were also determined in very low concentrations. These minerals formed syngenetically and epigenetically. The syngenetic stage is characterized mainly by the formation of pyrite, carbonates, silicates and sulphates, whereas the Fe-oxyhydroxides, partially the carbonates and almost all silicates are of detrital origin. During the epigenetic stage, carbonates, sulphates, clay minerals, pyrite, and Fe-oxyhydroxides were formed. Alteration products like gypsum, jarosite, limonite, chlorite, kaolinite, illite, mica, and calcite were generated due to the transformation of detrital and authigenic minerals.

Freshwater algal palynomorph records from Holocene deposits in the coastal plain of Rio Grande do Sul, Brazil

More than eighty samples collected from the surface of fresh water marsh, salt marsh, peat land, fluvial surface sediments and Holocene lagoon deposits in the coastal plain of the State of Rio Grande do Sul were analyzed for freshwater algal palynomorphs. The identified palynomorphs are Botryococcus, Pediastrum, Zygnema, Spirogyra, and Mougeotia. Three morphological types of Botryococcus colonies and two morphological types of Spirogyra spores are described. Four palynomorph assemblages from the surface sediments are detected. The freshwater algal palynomorphs from Holocene lagoon sediments of transgressive and regressive stages, and associated marine palynomorphs and pollen and spores of vascular plants reflect sea-level oscillations and climate variations.

Evaluation of plasma tissue factor and tissue factor pathway inhibitor levels in childhood hemangiomas

The purpose of the study was to evaluate the plasma levels of tissue factor (TF), an angiogenic marker, and tissue factor pathway inhibitor (TFPI), an antiproliferative protein, in the childhood hemangiomas at proliferative and regressive stages. The study included 30 patients with hemangiomas and 30 healthy children. Localization, number, stage, type, duration of growth, and complications of the hemangiomas were determined. Venous blood samples from all individuals were collected into citrated tubes and centrifuged. Supernatant plasma was separated, aliquated, and stored at -70 degrees C until samples could be assayed. Plasma levels of TF and TFPI were measured with quantitative ELISA kits. Plasma TF and TFPI levels did not show any significant difference between the study and control groups. When plasma TF and TFPI levels of the children in the control group and in the study group who were in proliferative and regressive stage were compared to each other, no statistically significant difference could be detected. Plasma TF and TFPI levels of our patients with hemangiomas were not different from healthy children and they did not show any significant difference in proliferative and regressive stages.

Liver regeneration: a critical toxicodynamic response in predictive toxicology

The objective of the present review is to discuss the importance tissue repair in the mixture risk assessment. Studies have revealed the existence of two stages of toxicity: an inflictive stage (stage I) and progressive or regressive stage (stage II). While much is known about mechanisms by which injury is inflicted (stage I), very little is known about the mechanisms that lead to progression or regression of injury. A wide variety of additional experimental evidence suggests that tissue repair impacts decisively on the final toxic outcome and any modulation in this response has profound impact in the final outcome of toxicity. We designed the present research to investigate the importance of tissue repair in the final acute hepatotoxic outcome upon exposures to mixture of toxicants comprising thioacetamide (TA), allyl alcohol (AA), chloroform (CHCl 3) and trichloroethylene (TCE). Dose response studies with individual compounds, binary mixtures (BM), ternary (TM) and quaternary mixtures (QM) have been conducted. Results of CHCl 3 + AA BM [Anand, S.S., Murthy, S.N., Vishal, V.S., Mumtaz, M.M., Mehendale, H.M., 2003. Tissue repair plays pivotal role in final outcome of supra-additive liver injury after chloroform and allyl alcohol binary mixture. Food Chem. Toxicol. 41, 1123] and CHCl 3 + AA + TA +TCE QM [Soni, M.G., Ramaiah, S.K., Mumtaz, M.M., Clewell, H., Mehendale, H.M., 1999. Toxicant-inflicted injury and stimulated tissue repair are opposing toxicodynamic forces in predictive toxicology. Regul. Phramcol. Toxicol. 19, 165], and two representative individual compounds (TA and AA) [Mangipudy, R.S., Chanda, S., Mehendale, H.M., 1995a. Tissue repair response as a function of dose in thioacetamide hepatotoxicity. Environ. Health Perspect. 103, 260; Soni, M.G., Ramaiah, S.K., Mumtaz, M.M., Clewell, H., Mehendale, H.M., 1999. Toxicant-inflicted injury and stimulated tissue repair are opposing toxicodynamic forces in predictive toxicology. Regul. Phramcol. Toxicol. 19, 165] are described in this review. In addition, modulation of tissue repair in the outcome of hepatotoxicity and its implications in the risk assessment have been discussed. Male Sprague–Dawley (S–D) rats (250–300 g) received a single i.p. injection of individual toxicants as well as mixtures. Liver injury was assessed by plasma alanine amino transferase (ALT) and histopathology. Tissue regeneration response was measured by [ 3H]-thymidine ( 3H-T) incorporation into hepatocellular nuclear DNA and PCNA. Only ALT and 3H-T data have been presented in this review for the sake of simplicity. Studies with individual hepatotoxicants showed a dose-related increase in injury as well as tissue repair up to a threshold dose. Beyond this threshold, tissue repair was inhibited, and liver injury progressed leading to mortality. Since the highest dose of individual compounds resulted in mortality, this dose was not employed for mixture studies. While CHCl 3 + AA BM caused supra-additive liver injury, QM caused additive liver injury. Due to the prompt and robust compensatory tissue repair, all the rats exposed to BM survived. With QM, the rats receiving the highest dose combination experienced some mortality consequent to the progression of liver injury attendant to suppressed tissue repair. These findings suggest that liver tissue repair, the opposing biological response that restores tissue lost to injury, may play a critical and determining role in the outcome of liver injury regardless of the number of toxicants in the mixture or the mechanism of initiation of injury. These data suggest that inclusion of this response in risk assessment might help in fine-tuning the prediction of toxic outcomes.

Stromal cells and extracellular matrix components in spontaneous canine transmissible venereal tumour at different stages of growth.

Stromal cells and extracellular matrix (ECM) components are important for tumour cell behaviour. Little is known about the role of stromal cells and ECM components in the progression and regression of spontaneous canine transmissible venereal tumour (CTVT). In this study, the stromal cell type was determined by immunohistochemical labelling with antibodies to desmin, vimentin and alpha-smooth muscle actin (alpha-SMA) during the progressive and regressive stages of spontaneous CTVT. The distribution of ECM components tenascin-C, chondroitin sulphate and versican were determined immunohistochemically, and hyaluronan distribution was determined using a biotinylated protein complex with specific affinity for hyaluronan. Stromal cells of tumours in both the progressive and regressive stage were positive for vimentin and negative for desmin. The number of stromal cells expressing alpha-SMA was significantly higher (P=0.001) in regressing tumours, than progressing tumours. These results suggest that the modulation of stromal cells that occurs during the regression of CTVT is similar to that occurring during wound healing. Tenascin-C was weakly expressed in the stroma of tumours in the progressive stage and in regions of the regressing tumours with tumour infiltrating lymphocytes (TILs), but intensely expressed in the stroma of tumours in late regressive stage. In addition, tenascin-C was also expressed in the cytoplasm of some tumour cells in the late regressive stage. A strong stromal tenascin-C intensity was significantly associated with regressing tumours (P=0.001). Strong stromal hyaluronan intensity and a high proportion of hyaluronan-positive tumour cells were significantly associated with progressing tumours (P=0.001). This suggests that hyaluronan is involved in the growth of the tumour. There was no significant difference in the expression of chondroitin sulphate and versican in progressing and regressing tumours.

P‐65 Canine cutaneous histiocytoma: morphology and morphometry

Canine cutaneous histiocytoma is a common tumor of young dogs. Nodules are single or multiple, alopecic and well demarcated. We studied 15 young dogs with cutaneous histiocytoma. Cutaneous nodules were cytologically and histologically investigated using routine techniques. The subject for morphometry was the nuclear area of histiocytes. The figures were statistically interpreted (Student's t‐test). Cytologically, histiocytes represented the largest population, being large‐sized cells. The nucleus:cytoplasm ratio was large with oval or bean‐shaped nuclei and a fine arrangement of chromatin. The cytoplasm was discrete and basophilic, or abundant and foamy. Five regressive stages were histologically described. Stage 1 was represented by dermal and hypodermal histiocyte proliferation, covered by an intact, uninfiltrated and atrophic epidermis. Epidermal ulcers and necrotizing foci with neutrophilic, lymphocytic and plasma cell infiltrations occurred in Stages 2, 3 and 4. Stage 5 looked like a chronic dermatitis. In Stage 1, the nuclear area was the smallest (4615 ± 62 pixels) with a small coefficient of variation (14.28%), proving a homogeneous population. Stage 2 histiocytes had a larger and more heterogeneous nuclear area (6116 ± 130 pixels) with a 21.12% coefficient of variation. In Stage 3, the average nuclear area (6431 ± 115 pixels) was larger than that for Stage 2 and had a 19.18% coefficient of variation. There were no significant differences between the nuclear areas of histiocytes from Stages 2 and 3; however, significant differences occurred between Stages 1 and 2, and between Stages 1 and 3. Funding: Self‐funded.

Lateglacial and Holocene sea level changes in semi-enclosed seas of North Eurasia: examples from the contrasting Black and White Seas

A comparison of the Black and White Seas, which differ in their tectonic, glacial and climatic history but which share a strong dependence upon limited water exchange with the world ocean, represents an opportunity for the identification of major factors controlling sea level changes during the Lateglacial and Holocene and for the correlation of these changes. Existing data were critically analyzed and compared with the results of geological, geomorphological and palaeohydrological studies obtained by the present authors during the past two decades. We conclude that glacioeustatic processes played a major role in relative sea level changes on most coasts of both areas. However, along several coastlines, other factors overwhelm glacioeustasy during some time intervals. In the Black Sea, water level rose from its minimum position, −100–120 m, at 18–17 ka BP, to −20–30 m at nearly 9 ka BP. In the White Sea, the decreasing trend in relative sea level is well illustrated on the Kola Peninsula and in Karelia, subject to glacioisostatic emergence. A drastic sea level fall from +15 to −25 m occurred with the drainage of glacial lakes in the eastern White Sea (12.5–9.5 ka BP). The Black and White Sea histories changed drastically in the early Holocene or in the beginning of the middle Holocene (9.5–7.5 ka BP) due to the intrusion of water from the Mediterranean and the Barents seas, respectively. During this period, the White Sea developed under the strong influence of the formation of “ice shelves” and “dead ice” blocks, retreating glaciers, as well as of glacioisostatic and related processes. The Black Sea history, however, was determined by water exchange with the Mediterranean via the shallow Dardanelles and Bosporus straits (outflow from the Black Sea 10–9.5 ka BP and inflow from 9–7.5 ka BP according to various data), and, partially, by river discharge variations caused by climatic changes on the Russian Plain. The hypothesis of a catastrophic sea level rise from −120–150 to −15–20 m nearly 7550 calendar years BP is not supported by our data. Water intrusion from the Mediterranean was fast but not catastrophic. In the Black Sea, periods of high sea levels after the intrusion of Mediterranean waters are dated from four sedimentary complexes, Vityazevian, Kalamitian, Dzhemetian and Nymphaean, from nearly 7.5, 7–6, 5.5–4.5 and 2.2–1.7 ka BP, respectively. A fluctuating pattern of sea level change was established in the White Sea after the drainage of proglacial lakes and intrusion of ocean waters at the end of the early Holocene (nearly 8.5–8.2 ka BP). Major periods of sea level rise in the White Sea are dated from the late Boreal–early Atlantic (8.5–7.5 ka BP), late Atlantic (6.5–5.2 ka BP), middle Subboreal (4.5–4 ka BP) and middle Subatlantic (1.8–1.5 ka BP). Fluctuations of relative sea level during the middle and late Holocene were possibly on the order of several meters (from +2–3 to −2–3 m in the Black Sea and from +3–5 to −2–3 m in the White Sea). Lower estimates of regressive stages are principally derived from archaeological data on ancient settlements in tectonically submerging deltaic areas and cannot be regarded as reliable. Palaeohydrological analysis does not indicate that intensive (15–25 m or greater) sea level fluctuations were present in the Black Sea or in the White Sea during the middle and late Holocene. Instead, such analysis provides independent evidence to support the argument that significant differences in water level between the Black Sea and the Mediterranean could not be maintained for an extended period of time.

PATHOBIOLOGY OF ANDROGENETIC ALOPECIA

Human hair morphogenesis is a dynamic process caused by the remodelling of the skin. Hair growth is cyclic in mammals consisting of three distinct stages: an active stage (anagen), a regressive stage (catagen), and a resting stage (telogen). One disorder in this process is gradual balding of the scalp called androgenetic alopecia. Little is known about the cell biological or molecular mechanisms involved and thus very little treatment is currently available. In this review we focus on the most significant parameters affecting hair growth which participate in baldness.

Fragments on New Media Arts and Science

Fragments on New Media Arts and Science

Probable Endogenic Origin of Conglomerate-type Rocks on the Southeastern Coast of the White Sea

The southeastern coast of the White Sea and Kii Island incorporates outcrops of conglomerate-type rocks similar to boulder dikes filling tensile fractures in the early Precambrian basement of the platform. They are related to the southwestern flank of the Onega Graben representing the southeastern segment of the Onega–Kandalaksha paleorift. Genesis of these conglomerate-type rocks, previously considered sedimentary ones, is problematic. Special study of the cement of these rocks revealed that it has probably an endogenic nature. It is dominated by carbonate material replacing ultramafic volcanic glass. Carbonatization and analcime mineralization took place at the regressive stage of cement formation within a temperature range of 450–550°C with active release of H2O- and CO2-saturated fluids. Data on the isotopic composition (δ13C and δ18O) for carbonate material of cement from the brecciated rocks testify that the carbonatization was related to input of deep-seated carbon dioxide under subsurface environment. The studies carried out allow us to suppose that these rocks were formed as a result of consolidation of solid–gaseous suspensions inside fractures in the crystalline basement. Penetration of fluidized material along them produced dike-shaped bodies. Such rocks are recently called “fluidizates”. The sources of solid–gaseous suspension fluxes were basic magmas with a high content of volatiles. Discharge of gases from the magmas was caused by their decompression due to the appearance of tensile zones in lithosphere during rifting.

Neoproterozoic tectonic and climatic evolution recorded in the Gariep Belt, Namibia and South Africa

ABSTRACT The Pan‐African Gariep Belt in south‐western Namibia and westernmost South Africa provides an excellent window into the interplay between tectonic and climatic changes during the Neoproterozoic era. Recently acquired chemostratigraphic data from cap carbonate sequences above glaciogenic diamictite horizons, together with U–Pb zircon and Pb–Pb carbonate ages, indicate sedimentation in the Gariep Basin from continental break‐up around 770 Ma to basin closure and continent collision around 545 Ma. The basin is subdivided into an eastern failed rift graben and a western half graben that evolved into an oceanic basin between the Kalahari and the Rio de la Plata cratons. Three megasequences are distinguished in the external, para‐autochthonous part of the belt (Port Nolloth Zone): an early continental, predominantly siliciclastic, sag rift megasequence (M1), a passive continental margin, carbonate‐rich megasequence (M2), and a syn‐orogenic carbonate and flysch megasequence (M3). Two glaciogenic diamictite horizons at the end of M1 and M2 are recognized and they are correlated with the global ∼750 Ma Sturtian and ∼580 Ma Marinoan glaciations, respectively. While the former is restricted to proximal continental rift shoulders, the latter extends into the oceanic realm which marks the internal part of the belt (Marmora Terrane). Only the younger diamictite is associated with iron formation. The sequence of regressive and transgressive stages recorded by the sediment fill does not reflect simply the tectonic evolution from rifting to drifting and eventual basin closure, but is strongly controlled by severe climatically induced sea‐level changes that were either competing with or reinforcing tectonically induced sea‐level changes.