Border Of Section Research Articles

Installation of the developing nephron in the fetal human kidney during advanced pregnancy

BackgroundThe kidneys of preterm and low birth weight babies reflect vulnerability, since several noxae can evoke the termination of nephron formation. This again leads to oligonephropathy with severe consequences for health in the later life. While the clinical parameters have been intensely investigated, only little is known about the initial traces left by the noxae. For the fetal human kidney, solely the lack of basophilic S-shaped bodies and the reduction in width of the nephrogenic zone were registered. It is not known in how far also the involved progenitor cells, the earlier nephron stages, the collecting duct (CD) ampullae, and the local interstitium are collaterally harmed.AimThe interstitium at the forming nephron is heterogeneously structured. Thereby, it fulfills quite different mastering and integrative tasks. Since data dealing with the installation of a nephron is not available, the microanatomical features were recorded.ResultsThe microscopic specimens show that the installation of the transient stages of nephron anlage is not synchronized. Instead, it is controlled within a nephrogenic compartment of the nephrogenic zone. It starts near the renal capsule by positioning the nephrogenic niche so that the nephrogenic progenitor cells face the epithelial progenitor cell at the tip of a CD ampulla. Then, the induced nephrogenic progenitor cells assimilate in the pretubular aggregate. While its medial part remains opposite the head of the CD ampulla, at its proximal end, the primitive renal vesicle is formed. Only a part of it separates to stick to the section border between the head and conus of the CD ampulla. This marks the link with the future connecting tubule at the distal pole of the extending renal vesicle. Meanwhile, the proximal pole is mounted next to the connecting tubule of an earlier developed nephron. The resulting two-point mounting serves a common elongation of the conus at the CD ampulla and the medial aspect of the comma-shaped body. In the S-shaped body, it supports to defoliate the arising glomerulus and to link it with the perforating radiate artery at its deep lateral aspect.ConclusionsThe investigation depicts that the installation is an interactive process between the stages of nephron anlage and its structural neighbors. A special meaning has the interjacent interstitium. It is vital for the positioning, shaping, and physiological integration. Due to its special location, this is mainly exposed to noxae.

Determination of the capacity of the two-lane acceleration lanes with a central island

Interconnection sections of exit ramps at different levels with motorways are one of the main sources of traffic hindrance, so special attention should be paid to ensuring the capacity of such areas. Dual-lane motorway connections are often made using two-lane acceleration lanes, with safety islands as a method of increasing their capacity. In order to develop recommendations for determining the capacity of such acceleration lanes, the author carried out experimental studies of the patterns of DLC maneuvers within the highways on the sections bordering the entrances. The studies were carried out by recording the trajectories of vehicles that perform a maneuver of exit from the entrance to the highway. On the basis of the carried out researches an improvement of a method of calculation of capacity of two-lane acceleration lanes is offered. The results of the studies are recommended for use in the design of highways and intersections at different levels of them, as well as for the reconstruction of the highway lanes in order to increase their capacity.

A bűnüldözés és a bűnmegelőzés rendészettudományi tényezői című tudományoskonferencia-kötetről

Az említett tudományoskonferencia-kötet, amely egy igazi, nagybetűs könyv, a szó klasszikus tipográfiai értelmében. A külső, a tudomány tiszteletét mutató hófehér, fényes papír borító, amely magába foglalja a 357 számozott lapoldalt, ami szintén azt erősíti az olvasóban, hogy ebben lesz mit olvasni. A fedőlapon szinte kiált a határőr-zöld színű feliratozás, a határőrség emblematikus figurája a turulmadár, a karmai közt fogott karddal, amely már utal a kötet készítőire. A kiadás helyeként megjelölt Pécs a megszűnt Határőr Igazgatóság központja volt 2007 végéig. A rendszerváltozás időszakában létrejött Magyar Hadtudományi Társaság 1991-től működő Határrendész, később Határőr Szakosztályának keretein belül 2000-ben alakult meg nyolc lelkes határőr tiszttel, a tudományt tisztelő és művelő szakemberekkel a pécsi szakcsoport. Ez a jövőre két évtizedes múltra visszatekintő gárda az alapító, Szent László ünnepéhez kapcsolt konferenciáját a következő évben szervezte meg először. Az első tudományos kötetét 2002-ben adta ki, a jelenlegi a XXI. számot viseli.

Effect of cutting parameters on section borders of the empirical specific cutting force model for cutting with micro-sized uncut chip thickness

Miniaturization is a general trend in part manufacturing: the size of the components and the rate of corresponding tolerance shrink. This fact makes the appliance of precision- and micromachining operations required. Mechanical cutting has been successfully adapted to perform precision machining and microcutting with uncut chip thickness typically under 0.01 mm. Size effect is dominant in this scale: the amount of specific cutting energy greatly increases according the type of material deformation occurring at the cutting edge radius. The multi-sectioned empirical model of specific cutting force proved to be an effective model to indicate such transient mechanisms. Aim of current research is to describe the effect of cutting parameters on the known section borders (called boundary chip thicknesses) in the model of specific cutting force. As a result, the newly created empirical models involve feed rate and cutting speed as direct input parameters, and assumption has been made to explain the physical meaning behind boundary chip thicknesses from the aspect of material deformation.

Lesiones intraepiteliales en pacientes atendidas en el Hospital General Docente “Mártires del 9 de Abril”, 2010

Las lesiones neoplásicas del cérvix pueden evolucionar en un período de meses o años hasta desarrollar cáncer. Mediante un estudio cuantitativo de tipo prospectivo descriptivo se alcanzó el propósito de caracterizar el estado de las patologías de cuello uterino en las pacientes con diagnóstico definitivo de citología anormal, que fueron remitidas a la consulta especializada en el Hospital “Mártires del 9 de Abril” durante el año 2010; cuya población de estudio estuvo conformada por 259 pacientes, de las cuales fueron seleccionadas 248 a través de un muestreo no probabilístico en base a criterios. Prevalecieron aquellas con edades comprendidas entre 25 y 54 años, así como las secundíparas y las que tuvieron su primera relación sexual antes de cumplir los 20 años. Las lesiones intraepiteliales de bajo grado predominaron. Se observó independencia entre las variables resultados citológicos y antecedentes personales de infección vaginal, en contraposición de la dependencia significativa entre los resultados de tres métodos diagnósticos empleados; así como, entre resultados histológicos y conducta terapéutica. Las reintervenciones que se requirieron fueron debido a la presencia de bordes de sección quirúrgica positivos y la detección de carcinoma microinfiltrante.

Extension of empirical specific cutting force model for the process of fine chip-removing milling

Specific cutting force is a frequently used parameter to classify and describe the energetic environment of mechanical machining operations. It defines the ratio of cutting forces and theoretical chip section during machining. This definition makes it possible to create general technological models for precise process planning. Classical models of cutting forces already indicate that specific cutting force cannot be modelled using a single low-level analytical function due to the marked presence of size effect. The problem is amplified in the case of micro-chip forming, where the relative scale of elastic and plastic deformations in the machined material differ from those experienced in conventional cutting conditions. Previous research proved that boundaries of specific cutting forces can be defined by values of exact uncut chip thicknesses, in which case the sections of specific cutting force may indicate different types of material deforming processes. The aim of current research presented in this paper is to extend the empirical model of specific cutting force for fine chip-removing cutting processes by identifying a new boundary section of uncut chip thickness. Therefore, a new boundary chip thickness was defined based on data obtained with reference to experimental cutting force. New boundary chip thickness follows the so-far proven tendencies of already known section borders and this enables the extension of the validity range of classical approaches presented by specific cutting force models beyond macro-scaled chip forming to micro-scaled chip forming processes. The extension of the model considers the effect of cutting parameters, primarily that of feed rate.

Radial Bearings with Porous Elements

This paper presents the analytical model of the radial bearing of the finite length with the two-layer porous insert obtained on the basis of the dimensionless equations of movement of a viscous incompressible lubricant in an operating clearance and in porous layers of a bearing sleeve and continuity equations as well. We are analyzing the case when permeability of porous layers on the border of section of a two-layer insert accepts one value. The lubricant moves in a circumferential direction through a bore in a bearing body and the subsequent filtration occurs through insert pores. Permeability anisotropy of porous layers is taken into consideration in radial and circumferential directions.As a result of the given task, we have obtained the field of speeds and pressure in porous layers and in the lubricant layer. Analytical dependences for components of a vector of supporting force and the friction moment have been found, and we have also defined the loading factor and friction factor. Moreover, in our calculations we have revealed and used the parameter characterizing specificity of lubrication feeding in a circumferential direction. It is proved that the rational mode of operation is reached by a design of a two-layer porous insert given when the resistance factor increases more intensively and from the parameter ψ, and from a relative eccentricity ɛ in comparison with the bearing having a single-layer insert. Hence, anisotropy of permeability of porous layers in a circumferential and radial direction has a defined possibility of practical application of this new model.

New marine mammal faunas (Cetacea and Sirenia) and sea level change in the Samlat Formation, Upper Eocene, near Ad-Dakhla in southwestern Morocco

The Samlat Formation is well exposed in coastal sections bordering the Atlantic Ocean south of Ad-Dakhla in southwestern Morocco. Here some 22m of rhythmically-bedded, chert-rich, marine siltstones and marls are overlain by 1–1.5m of vertebrate-bearing microconglomeratic sandstone, another 4–8m of rhythmically-bedded siltstone and marl, and finally a second 3–6m unit of vertebrate-bearing muddy sandstone. The microconglomeratic and muddy sandstones represent low sea stands in what is otherwise a deeper water sequence. Cetacean skeletons are rare but cetacean vertebrae are common in the lower sandstone (bed B1), where many show the effects of reworking. The cetaceans in bed B1represent a minimum of five species, from smallest to largest: cf. Saghacetus sp., cf. Stromerius sp., Dorudon atrox, cf. Dorudon sp., and Basilosaurus isis. Bed B1 yields rib fragments that may represent sirenians, but sirenians, if present, are rare. The only identifiable cetacean found in the upper sandstone (bed B2) is Basilosaurus sp. Dugongid sirenians identified as cf. Eosiren sp. are the most common mammal in bed B2. We interpret co-occurrence of the typically Early Priabonian species Dorudon atrox and Basilosaurus isis with smaller species more like Middle Priabonian genera Saghacetus osiris and Stromerius nidensis to indicate that bed B1 was deposited during low sea stand Pr-2 between the Early and Middle Priabonian (between the early and middle Late Eocene). Bed B2 is separated from B1 by an interval of deeper water sediment accumulation. Bed B2 could represent a later phase of Pr-2 or a subsequent Priabonian low sea stand (possibly Pr-3).

Investigation of curves set by cubic distribution of curvature

Purpose. Further development of the geometric modeling of curvelinear contours of different objects based on the specified cubic curvature distribution and setpoints of curvature in the boundary points. Methodology. We investigate the flat section of the curvilinear contour generating under condition that cubic curvature distribution is set. Curve begins and ends at the given points, where angles of tangent slope and curvature are also determined. It was obtained the curvature equation of this curve, depending on the section length and coefficient c of cubic curvature distribution. The analysis of obtained equation was carried out. As well as, it was investigated the conditions, in which the inflection points of the curve are appearing. One should find such an interval of parameter change (depending on the input data and the section length), in order to place the inflection point of the curvature graph outside the curve section borders. It was determined the dependence of tangent slope of angle to the curve at its arbitrary point, as well as it was given the recommendations to solve a system of integral equations that allow finding the length of the curve section and the coefficient c of curvature cubic distribution. Findings. As the result of curves research, it is found that the criterion for their selection one can consider the absence of inflection points of the curvature on the observed section. Influence analysis of the parameter c on the graph of tangent slope angle to the curve showed that regardless of its value, it is provided the same rate of angle increase of tangent slope to the curve. Originality. It is improved the approach to geometric modeling of curves based on cubic curvature distribution with its given values at the boundary points by eliminating the inflection points from the observed section of curvilinear contours. Practical value. Curves obtained using the proposed method can be used for geometric modeling of curvilinear contours of objects in different industry branches.

Effect of self-tapping screws on moisture induced stresses in glulam

Glulam structures in service may exhibit considerable moisture induced stresses perpendicular to grain that may affect the load-bearing capacity. An option to enhance the low tensile strength of glulam perpendicular to grain is the use of self-tapping screws, which has shown promising results in constant climates. In varying climates, however, the performance of such screw reinforcements is currently not well understood. The present paper reports results of both experiments and numerical simulations investigating the effect of self-tapping screws on moisture induced stresses arising in glulam exposed to single wetting and drying climate changes. It is shown that during wetting, the screw reinforcement significantly reduces the maximum tensile stresses arising in the cross section centre. With screw distances from 70 to 210mm, stress reductions by 70–30% are achieved (compared to unreinforced glulam beams). The tensile stresses arising between the reinforcing screws depend not only on the screw distance, but also strongly on the cross section width and the annual ring pattern of the laminates. During drying, the additional restraint caused by the reinforcing screws resulted in a slight increase of the tensile stresses at the cross section border. These were, however, rather low compared to the tensile stresses arising during wetting.

Complex formation on the basis of copolymers of an alternating structure vinylbutyl ether and malein anhydride with the polymer of cationic type on interphase border

For the first time are studied interpolyelectrolyte reactions of copolymers of an alternating structure butyl vinyl ether – malein anhydride with the polymer of cationic type – polydimethylaminoethylmethacrylate in a water solution and on interphase border of two immiscible liquids. The structure of the polyelectrolyte complexes , formed in water solutions and on border of section of phases is established, is shown that the polyelectrolyte complexes are steady against influence of ionic force. Also it is established that at contact of solutions of butyl vinylether – malein anhydride in butanol with water solutions of polydimethylaminoethylmethacrylate on border of section of phases to form a film.

Surgical treatment of cystic neoplasms of the pancreas

Diagnosis and treatment of cystic neoplasms of the pancreas increased significantly in the last decades. There are only a few Brazilian publications on these tumors. The majority of them are limited to reports of one or few cases. To present our experience with 27 patients with cystic neoplasms of the pancreas. Demographic data, clinical manifestations, diagnostic exams, surgical procedures, postoperative complications, and follow-up data of 27 patients with cystic neoplasms of the pancreas were analyzed, according to the histological type of the tumor. There were 10 (37%) serous cystic tumors, 10 (37%) mucinous cystic tumors, 4 (15%) intraductal papillary mucinous tumors, and 3 (11%) solid pseudopapillary tumors or Frantz tumor. All serous cystic tumors, 6 (60%) mucinous tumors, 2 (50%) intraductal papillary mucinous tumors, and 2 (67%) solid pseudopapillary tumors were benign. The age of the patients varied from 31 to 82 years and all tumors were more common in female. Two patients had been treated previously as a pseudocyst. Surgical procedures depended on the location and extension of the tumor. Two patients underwent only laparotomy with tumor biopsy, one cholecystectomy with Roux-en-Y hepaticojejunostomy for jaundice treatment, 6 pancreatoduodenectomy, and 18 partial pancreatectomy. The most common postoperative complication was pancreatic fistula (n = 5; 19%). One patient died of necrotic pancreatitis. Of the 10 patients with serous cystic tumor, only 1 had tumor recurrence at the section border. The three patients with mucinous cystoadenocarcinoma in which was not possible to resect the tumor, died 6 to 24 months after laparotomy. The six patients with benign mucinous tumors did not have tumor recurrence. The most common cystic neoplasms of the pancreas are serous and mucinous cysts. These tumors are more frequent in female. Although almost all serous cysts are benign, 40% of mucinous cysts are malign. Misdiagnosis may delay appropriate treatment and increase mortality.

Correlation of Middle Devonian Hamilton Group-equivalent strata in east-central North America: implications for eustasy, tectonics and faunal provinciality

Abstract An integrated approach, involving nearly all available biostratigraphic data, event and sequence stratigraphy, has been utilized in correlation of the Middle Devonian (latest Eifelian–Givetian) Hamilton Group and equivalent strata in north-central North America. This approach permits high-resolution correlation of strata equivalent to the Oatka Creek (upper Marcellus), Skaneateles, Ludlowville and Moscow Formations from New York into sections bordering the Michigan Basin in Ontario, Canada, as well as southern Michigan, northern Ohio and Indiana, USA. Most member and submember-scale units, herein slightly redefined and interpreted as 3rd and 4th order sequences, respectively, and their bounding condensed beds can be correlated regionally. Moreover, many faunal patterns also persist across this region, which, together with sequence stratigraphy, provides a bridge for correlation into the Michigan Basin. The detailed stratigraphy presented herein permits a more-resolved understanding of far-field tectonics, eustasy and biotic responses during the Middle Devonian. Allocyclic processes, primarily eustasy, played a key role in generating persistent sedimentary cycles. Episodes of rapid mud sedimentation occurred over large areas of the cratonic interior, distal to Acadian source terrains. The major Algonquin–Findlay Arch, which presently separates the Michigan Basin from the Appalachian foreland basin, was not present during deposition of these strata. Conversely, a roughly north–south trending region, running approximately through present-day Cleveland, Ohio, was first a local subsiding area during late Eifelian–early Givetian time and then underwent topographic inversion to form a local arch at which upper Hamilton units were condensed and then bevelled during the later Givetian; we infer that this feature may represent a migrating forebulge. Finally, fossil biotas do not show strong partitioning into Appalachian and Michigan basin faunal subprovinces during the early Givetian, as there appears to have been no physical barrier to migration at least in the study area. However, Hamilton-equivalent strata in the most proximal portion of the Appalachian Basin do show a relatively minor admixture of typical Michigan Basin taxa with normal Hamilton forms.

Model for Plateau border drainage of power-law fluid with mobile interface and its application to foam drainage

A model for drainage of a power-law fluid through a Plateau border is proposed which accounts for the actual Plateau border geometry and interfacial mobility. The non-dimensionalized Navier–Stokes equations have been solved using finite element method to obtain the contours of velocity within the Plateau border cross section and average Plateau border velocity in terms of dimensionless inverse surface viscosity and power-law rheological parameters. The velocity coefficient, the correction for the average velocity through a Plateau border of actual geometry compared to that for a simplified circular geometry of the same area of cross section, was expressed as a function of dimensionless inverse surface viscosity and flow behavior index of the power-law fluid. The results of this improved model for Plateau border drainage were then incorporated in a previously developed foam drainage model [G. Narsimhan, J. Food Eng. 14 (1991) 139] to predict the evolution of liquid holdup profiles in a standing foam. Foam drainage was found to be slower for actual Plateau border cross section compared to circular geometry and faster for higher interfacial mobility and larger bubble size. Evolution of liquid holdup profiles in a standing foam formed by whipping and stabilized by 0.1% β-lactoglobulin in the presence of xanthan gum when subjected to 16 g and 45 g centrifugal force fields was measured using magnetic resonance imaging for different xanthan gum concentrations. Drainage resulted in the formation of a separate liquid layer at the bottom at longer times. Measured bubble size, surface shear viscosity of β-lactoglobulin solutions and literature values of power-law parameters of xanthan gum solution were employed in the current model to predict the evolution of liquid holdup profile which compared well with the experimental data. Newtonian model for foam drainage for zero shear viscosity underpredicted drainage rates and did not agree with the experimental data.

Conización con asa de radiofrecuencia: Experiencia en el Hospital de San José

Con el objetivo de evaluar la experiencia del Hospital de San José en la conización cervical con asa de radiofrecuencia, se realizó una investigación retrospectiva, transversal y analítica con 390 pacientes que fueron sometidas a dicho procedimiento en nuestro hospital entre abril de 1998 y marzo de 2004. Las variables evaluadas fueron: edad, factores de riesgo para cáncer cervical, diagnóstico citológico, colposcópico e histológico tanto de la biopsia dirigida como del cono, el manejo y seguimiento post-conización y las complicaciones. El rango de edad predominante fue de 26 a 35 años en 39% de los casos; el 73% eran portadoras de lesiones de alto grado y 14% de bajo grado por diagnóstico histológico previo al cono, 12% de las pacientes presentaron discordancia en citología – colposcopia - biopsia y 3% con sospecha de lesión oculta fueron sometidas al procedimiento. La correlación histológica biopsia vs. cono fue de 74%. En el 82% el cono fue suficiente, 14% de los casos presentaron bordes de sección comprometidos, 3% cubo endocervical positivo y 2% legrado del lecho del cono positivo. Al 23.6% de las pacientes se les realizó tratamiento complementario posterior a la conización, de las cuales el 75% fueron llevadas a histerectomia abdominal ampliada y 5% a reconización. La frecuencia de complicaciones fue muy baja (6.7%). Se concluyó que la conización del cérvix con asa de radiofrecuencia es una técnica quirúrgica efectiva para el diagnóstico y la terapia de las neoplasias intraepiteliales del cuello uterino.

Population abundance of the common hippopotamus Hippopotamus amphibius in the Haut Niger National Park, Republic of Guinea / Abondance de la population d'hippopotame commun Hippopotamus amphibius dans le Parc National du Haut Niger, République de Guinée

AbstractThe Republic of Guinea is thought to contain the largest population of common hippopotamus in West Africa. However, no systematic field survey has been carried out recently and the information available is limited to informal observations. To clarify the status of the common hippopotamus in Guinea, we carried out a biannual population survey along the section of the Niger River (the largest river in Guinea) within the Haut Niger National Park. We counted 93 hippopotamuses in 28 groups in the dry season and 77 hippopotamuses in 23 groups in the wet season. Mean group size and number of neonates did not change between the seasons. Hippopotomuses were more numerous along the river sections bordering uncultivated floodplains. This underlines the significance of this habitat (which is used as a grazing area) for conservation of this species. Haut Niger National Park is the most important protected area in Guinea for conservation of the common hippopotamus. Hippopotamus-human and -cattle conflicts in terms of floodplain use in the park's buffer zone should be closely monitored. Floodplain conversion to rice fields represents one of the most important threats to the long-term conservation of hippopotamus populations in Guinea.

Population abundance of the common hippopotamus Hippopotamus amphibius in the Haut Niger National Park, Republic of Guinea / Abondance de la population d'hippopotame commun Hippopotamus amphibius dans le Parc National du Haut Niger, République de Guinée

AbstractThe Republic of Guinea is thought to contain the largest population of common hippopotamus in West Africa. However, no systematic field survey has been carried out recently and the information available is limited to informal observations. To clarify the status of the common hippopotamus in Guinea, we carried out a biannual population survey along the section of the Niger River (the largest river in Guinea) within the Haut Niger National Park. We counted 93 hippopotamuses in 28 groups in the dry season and 77 hippopotamuses in 23 groups in the wet season. Mean group size and number of neonates did not change between the seasons. Hippopotomuses were more numerous along the river sections bordering uncultivated floodplains. This underlines the significance of this habitat (which is used as a grazing area) for conservation of this species. Haut Niger National Park is the most important protected area in Guinea for conservation of the common hippopotamus. Hippopotamus-human and -cattle conflicts in terms of floodplain use in the park's buffer zone should be closely monitored. Floodplain conversion to rice fields represents one of the most important threats to the long-term conservation of hippopotamus populations in Guinea.

Surface protrusion parameters in film columnar growth

In order to unfold the components of the interface width w of a columnar growth we measured by scanning tunneling microscopy the parameters that define the surface-protrusion SP shapes and their fluctuations in the paradigmatic Au thin film growth. The profiles of SP sections can be fitted by parabolas y =abx 2 . The scaling of the shape mean parameters as well as their fluctuations is obtained. These parameters allow the synthesis of the height distribution curve, as well as the separation of the columnar height fluctuations at the surface. The mean value of the slope at the paraboloid section borders is maintained constant during the growth. An unstable growth model of terrace surface currents with a selected slope that includes a steering effect at the step borders allows interpreting this border slope property and its value. The scaling exponents of the interface width, coarsening, and shape parameters agree with the values obtained from solid-on-solid simulations by other authors. of the parameters with a growth model. Specifically, this growth model is based on a system of terrace surface cur- rents controlled by a high Ehrlich-Schwoebel ES barrier and descending mechanisms that include a combination of knockout and steering processes. We also discuss a possible detachment mechanism driven by a chemical surface poten- tial. Finally, the cause of the faceting of the thicker films is analyzed.

A system for reconstructing and visualising three-dimensional objects

This paper presents a software program for three-dimensional separation, geometrical reconstruction and visualisation of subsurface objects. It uses as input a file containing 3-D co-ordinates of object points and respective attributes converted into a grey scale level. The software consists of two main components: recognition software; 3-D reconstruction and visualisation software. Based on the input file, the first component generates a set of planes, containing two-dimensional sections. If the information needed (i.e. the number of points) is insufficient, an approximation or interpolation method is applied to build smooth 2-D section borders. The first software component divides the set of all 2-D sections into subsets of similar 2-D sections. The second one uses each subset to build geometrically different 3-D subsurface objects. An experiment is performed to validate the program capabilities. Data obtained by prospective drills from the Aljustrel mine located in the South of Portugal is used for generation of the input file. The surfaces of three ore bodes are reconstructed and visualised from three different viewpoints. The main differences between the presented software program and some packages for 3-D modelling and visualisation are discussed.

The Holocene in the South-Eastern region of the Province Jujuy, North-West Argentina

Abstract The results reported are from three sedimentary sections bordering the Rio Grande and its tributary in San Salvador de Jujuy and surrounding areas. The prevailing precipitation in the area of investigation, at 1200 m elevation, is about 900 mm/yr and increases with altitude to 1300 mm/yr at 1700 m elevation. On the basis of these sections it is possible to recognize two Holocene dry phases and two humid phases. A dry period, from the Late Pleistocene until 8900 yr BP, is evident in the section Los Perales, in the form of a 3 m loess bed, rich in volcanic glass. The Hypsithermal period, beginning 8900 yr BP and ending 6400 yr BP or even later, is identified by two different fossil soil developments in the section Los Perales, as well as by several peat horizons in the section Rio Chico. In the first case, we can recognize intensive soil development in the Early Holocene levels, which can be separated into two soil development phases. These phases are represented by two B-horizons separated by a 15 cm thick loess bed, and are dated by C 14 to 8180±130 yr BP and 6470±100 yr BP. In the case of the Rio Chico section, the peat below a gravel bed was radiocarbon dated to 8930±130 yr BP 7610±130 yr BP, 6970±100 yr BP and 6470±110 yr BP. The middle Holocene in section Los Perales is characterized by a 45 cm thick loess deposit, which reflects predominantly dry conditions. The recurrence of moister conditions and corresponding soil development into vertisols is documented by several palaeosols, the older ones dating to 1340±50 yr BP.