HIV prevalence and contextual risk-factors among injection drug users in Harris County, Texas

Injection drug use is the third most frequent risk factor for new HIV infections in the United States. A dual mode of exposure: unsafe drug using practices and risky sexual behaviors underlies injection drug users' (IDUs) risk for HIV infection. This research study aims to characterize patterns of drug use and sexual behaviors and to examine the social contexts associated with risk behaviors among a sample of injection drug users. ^ This cross-sectional study includes 523 eligible injection drug users from Houston, Texas, recruited into the 2009 National HIV Behavioral Surveillance project. Three separate set of analyses were carried out. First, using latent class analysis (LCA) and maximum likelihood we identified classes of behavior describing levels of HIV risk, from nine drug and sexual behaviors. Second, eight separate multivariable regression models were built to examine the odds of reporting a given risk behavior. We constructed the most parsimonious multivariable model using a manual backward stepwise process. Third, we examined whether HIV serostatus knowledge (self-reported positive, negative, or unknown serostatus) is associated with drug use and sexual HIV risk behaviors. ^ Participants were mostly male, older, and non-Hispanic Black. Forty-two percent of our sample had behaviors putting them at high risk, 25% at moderate risk, and 33% at low risk for HIV infection. Individuals in the High-risk group had the highest probability of risky behaviors, categorized as almost always sharing needles (0.93), seldom using condoms (0.10), reporting recent exchange sex partners (0.90), and practicing anal sex (0.34). We observed that unsafe injecting practices were associated with high risk sexual behaviors. IDUs who shared needles had higher odds of having anal sex (OR=2.89, 95%CI: 1.69-4.92) and unprotected sex (OR=2.66, 95%CI: 1.38-5.10) at last sex. Additionally, homelessness was associated with needle sharing (OR=2.24, 95% CI: 1.34-3.76) and cocaine use was associated with multiple sex partners (OR=1.82, 95% CI: 1.07-3.11). Furthermore, twenty-one percent of the sample was unaware of their HIV serostatus. The three groups were not different from each other in terms of drug-use behaviors: always using a new sterile needle, or in sharing needles or drug preparation equipment. However, IDUs unaware of their HIV serostatus were 33% more likely to report having more than three sexual partners in the past 12 months; 45% more likely to report to have unprotected sex and 85% more likely to use drug and or alcohol during or before at last sex compared to HIV-positive IDUs. ^ This analysis underscores the merit of LCA approach to empirically categorize injection drug users into distinct classes and identify their risk pattern using multiple indicators and our results show considerable overlap of high risk sexual and drug use behaviors among the high-risk class members. The observed clustering pattern of drug and sexual risk behavior among this population confirms that injection drug users do not represent a homogeneous population in terms of HIV risk. These findings will help develop tailored prevention programs.^

A comparison of health behaviors of African -American male and female illicit drug users: Implications for community health practice

Prevalence of drug use, HIV, syphilis, and other STDs is particularly high in African-American populations. Although some studies have documented protective changes in health behaviors relevant to these outcomes, other research indicates that risky health behaviors are still widespread. Moreover, little is known about how African-American men and women have differed in their responses to calls to adopt protective behaviors. The study reported in this dissertation investigates gender differences in health risk behavior in a sample of 482 African American chronic, frequent injection drug and crack cocaine users residing in Houston, Texas. It uses baseline and 9 month follow-up data collected on this sample. Four major research questions are addressed. These questions are: Research question 1. What was the overall pattern of reduction in drug use for subjects in the sample? In particular, did subjects who reported a recent (30 day) reduction in drug use and needle sharing risk at baseline also report a reduction at follow-up? Research question 2. Is gender significantly associated with the overall pattern of risk reduction in drug injection observed in the two waves of the study? Research question 3. Is gender significantly associated with the overall pattern of reduction in the number of sexual partners observed in the two waves of the study? Research question 4. Is gender significantly associated with the overall pattern of increase in the use of barrier contraceptives in the two waves of the study? ^

Pollen and macroremains from sediment core Aschenhütte

The Upper Pleistocene sediments of the Aschenhütte sink-hole (west of Herzberg am Harz, Lower Saxony) enable one to make interesting correlations between palynological and geological results. The sequence is composed of limnic-telmatic deposits (Eemain to Lower Weichselian) and loess with paleosoils (Weichselian). Sedimentation started during the hornbeam-dominated phase of the Eemian interglacial period and continued throughout the Eemian, the Weichselian Brörup interstadial (sensu Andersen) and parts of the preceding and the following stadial phases, the Herning and the Rederstall stadials. As opposed to most of the known Eemian sites spruce was a major tree species during the hornbeam-dominated phase of the Eemian. The vegetational development during the interstadial phase does not show a period of climatic deterioration as is the case for the Brörup interstadial when considering regions with a more demanding vegetation or regions close to the natural boundaries of the tree species concerned. Pollen or seeds of Bruckenthalia and Picea omoricoides have not been found in the Aschenhütte cores. The limnic-telmatic sediments interlock with loess-paleosoils (Eemian soil and Lower Weichselian bleaching soils) at the lake shore. They are overlaid by loess paleosoils of the Stillfried-B interstadial (Hattorf soil and Lohne soil). Lake level fluctuations were determined by means of the facies distribution and isochrones as defined by pollen analysis. A relatively high stand of the lake level existed after the end of the Eemian interglacial and during the Brörup interstadial periods. In the course of the Herning stadial period the water level dropped, whereas during the Rederstall stadial phase the lake basin was covered by sediments and therefore dried up.

Tab. 1: Rb-Sr data on metasediments in the Shackleton Range

Summary: The stratigraphy of the Shackleton Range established by Stephenson (1966) and Clarkson (1972) was revised by results of the German Expedition GEISHA 1987/88. The "Turnpike Bluff Group" does not form a stratigraphic unit. The stratigraphic correlation of its formations is still a matter of discussion. The following four formations are presumed to belong to different units: The Stephenson Bastion Formation and Wyeth Heights Formation are probably of Late Precambrian age. The Late Precambrian Watts Needle Formation, which lies unconformably on the Read Group, is an independant unit which has to be separated from the "Turnpike Bluff Group". The Mount Wegener Formation has been thrusted over the Watts Needle Formation. Early Cambrian fossils (Oldhamia sp., Epiphyton sp., Botomaella (?) sp. and echinoderms) were found in the Mt. Wegener Formation in the Read Mountains. The Middle Cambrian trilobite shales on Mount Provender, which form the Haskard Highlands Formation, are possibly in faulted contact with the basement complex (Pioneers and Stratton Groups). They are overlain by the Blaiklock Glacier Group, for which an Ordovician age is indicated by trilobite tracks and trails, low inclination of the paleomagnetic field and the similarity to the basal units of the Table Mountain Quartzite in South Africa. The Watts Needle Formation represents epicontinental shelf sediments, the Mount Wegener Formation was deposited in a (continental) back-arc environment, and the Blaiklock Glacier Group is a typical molasse sediment of the Ross Orogen.

Thermal conductivity at DSDP Leg 60 Holes

A total of 1547 thermal conductivity values were determined by both the NP (needle probe method) and the QTM (quick thermal conductivity meter) on 1319 samples recovered during DSDP Leg 60. The NP method is primarily for the measurement of soft sedimentary samples, and the result is free from the effect of porewater evaporation. Measurement by the QTM method is faster and is applicable to all types of samples-namely, sediments (soft, semilithified, and lithified) and basement rocks. Data from the deep holes at Sites 453, 458, and 459 show that the thermal conductivity increases with depth, the rate of increase ranging from (0.18 mcal/cm s °C)/100 m at Site 459 to (0.72 mcal/cm s °C)/100 m at Site 456. A positive correlation between the sedimentary accumulation rate and the rate of thermal conductivity increase with depth indicates that both compaction and lithification are important factors. Drilled pillow basalts show nearly uniform thermal conductivity. At She 454 the thermal conductivity of one basaltic flow unit was higher near the center of the unit and lower toward the margin, reflecting variable vesicularity. Hydrothermally altered basalts at Site 456 showed higher thermal conductivity than fresh basalt because secondary calcite, quartz, and pyrite are generally more thermally conductive than fresh basalt. The average thermal conductivity in the top 50 meters of sediments correlates inversely with water depth because of dissolution of calcite, a mineral with high thermal conductivity, from the sediments as the water depth exceeds the lysocline and the carbonate compensation depth. Differences between the Mariana Trench data and the Mariana Basin and Trough data may reflect different abundances of terrigenous material in the sediment. There are remarkable correlations between thermal conductivity and other physical properties. The relationship between thermal conductivity and compressional wave velocity can be used to infer the ocean crustal thermal conductivity from the seismic velocity structure.

Sobre la compatibilidad entre realismo y relativismo conceptual : Un exámen de la tesis de Putnam, desde un punto de vista lógico

Las indagaciones en la pregunta por lo que hay permiten distinguir a grandes rasgos entre dos enfoques: uno, el de los pensadores que entendieron que el tema a investigar era la naturaleza y estructura del mundo, y otro, el de aquellos quienes, al sostener que describir el mundo no es simplemente copiarlo, atendieron a lo que se llamó esquema conceptual: esto es, al marco conceptual cuya forma toman las descripciones del mundo. La situación se puede plantear como un dilema, ninguno de cuyos cuernos permite alentar esperanzas de avances bien fundados. O bien se pretende describir el mundo, tal como es, sin contemplar el hecho de que esa descripción incluye elecciones conceptuales propias de un sujeto, o bien se centra la investigación en los rasgos de el/los esquema/s conceptual/es imprescindibles para construir una descripción del mundo, imposibilitando, con ello, el acceso a la realidad tal como ésta es. En el siglo XX se cuenta con recursos de sistemas de lógica considerablemente más desarrollados y abarcadores (en sus posibilidades de aplicación) que los anteriores. Tales recursos brindan nuevas posibilidades de abordaje de la pregunta por lo que hay, no sólo por los ámbitos que se clarifican mediante ellos, sino también por el sustento que ofrecen para la reflexión filosófica los resultados obtenidos. Los avances producidos en el ámbito de la lógica en algo más de un siglo tuvieron variadas repercusiones en el enfoque y el tratamiento de distintas cuestiones filosóficas. Así, se ha echado mano a conceptos y recursos de lógica al considerar preguntas acerca de la estructura del mundo. Para la determinación de los componentes de la realidad se ha recurrido a la lógica, desde diversas posiciones filosóficas. Por ejemplo, se ha entendido que la lógica subyacente a la teoría científica brinda en algún sentido elementos para determinar la ontología (o para descartar la posibilidad de hacerlo, o para establecer qué función cumple la noción de ontología en la teoría científica). También, desde una óptica más amplia, se ha intentado mostrar que el uso del lenguaje tiene consecuencias respecto de la ontología. Hilary Putnam ha sugerido la posibilidad de ser al mismo tiempo un realista y un relativista conceptual. Involucra consideraciones como las mencionadas, respecto de lógica y ontología. Su objetivo es el intento de hacer justicia a la realidad y al misterio de nuestro mundo de sentido común. Tomo esta tesis como una propuesta de trabajo. Me interesa pensar en cómo ofrecer algunos elementos de juicio para evaluar sus alcances. Para ello, examino la sugerencia de Putnam mediante un ejemplo construido con ese objetivo. Entiendo que se requerirán, al menos, dos esquemas conceptuales diferentes: al que surgiría de la lógica de orden 1, tal como la desarrolla Quine, y al que podría obtenerse a partir de la teoría de objetos no existentes de Castañeda. Se contará así con elementos de juicio más precisos que los habituales para evaluar las consecuencias que se seguirían para la ontología en caso de sostener ambos esquemas conceptuales, en consonancia con la propuesta de Putnam que se ha tomado como objetivo general del proyecto

Temperature dependent growth and inorganic ion composition of haemolymph of juvenile Sepia officinalis, 2006

B Body wet weight and mantle length of juvenile Sepia officinalis were monitored over a peroid of five weeks. The animals had hatched in our aquarium system in Bremerhaven, Germany at 16°C and were descendants of individuals collected in the Oosterschelde estuary, Netherlands. Animals were kept in natural sea water at 10 or 17°C and fed small live shrimp (Palaemonetes varians) ad libitum daily. At the end of the experiment some animals kept at 17°C were sacrificed using ethanol. Haemolymph was withdrawn from the head vein using syringe and needle. Haemolymph samples were stored at -20°C until Na+, Cl-, K+, Mg2+, Ca2+ and SO42- concentrations were determined using ion chromatography. Mean body weight more that tripled at 17°C during the investigation period, while growth was impared by exposue to 10°C. Haemolymph ion concentrations were similar to those in sea water, except for sulphate. The concentration of this ion in the haemolymph was more that ten times lower than in sea water.

Sobre la compatibilidad entre realismo y relativismo conceptual : Un exámen de la tesis de Putnam, desde un punto de vista lógico

Las indagaciones en la pregunta por lo que hay permiten distinguir a grandes rasgos entre dos enfoques: uno, el de los pensadores que entendieron que el tema a investigar era la naturaleza y estructura del mundo, y otro, el de aquellos quienes, al sostener que describir el mundo no es simplemente copiarlo, atendieron a lo que se llamó esquema conceptual: esto es, al marco conceptual cuya forma toman las descripciones del mundo. La situación se puede plantear como un dilema, ninguno de cuyos cuernos permite alentar esperanzas de avances bien fundados. O bien se pretende describir el mundo, tal como es, sin contemplar el hecho de que esa descripción incluye elecciones conceptuales propias de un sujeto, o bien se centra la investigación en los rasgos de el/los esquema/s conceptual/es imprescindibles para construir una descripción del mundo, imposibilitando, con ello, el acceso a la realidad tal como ésta es. En el siglo XX se cuenta con recursos de sistemas de lógica considerablemente más desarrollados y abarcadores (en sus posibilidades de aplicación) que los anteriores. Tales recursos brindan nuevas posibilidades de abordaje de la pregunta por lo que hay, no sólo por los ámbitos que se clarifican mediante ellos, sino también por el sustento que ofrecen para la reflexión filosófica los resultados obtenidos. Los avances producidos en el ámbito de la lógica en algo más de un siglo tuvieron variadas repercusiones en el enfoque y el tratamiento de distintas cuestiones filosóficas. Así, se ha echado mano a conceptos y recursos de lógica al considerar preguntas acerca de la estructura del mundo. Para la determinación de los componentes de la realidad se ha recurrido a la lógica, desde diversas posiciones filosóficas. Por ejemplo, se ha entendido que la lógica subyacente a la teoría científica brinda en algún sentido elementos para determinar la ontología (o para descartar la posibilidad de hacerlo, o para establecer qué función cumple la noción de ontología en la teoría científica). También, desde una óptica más amplia, se ha intentado mostrar que el uso del lenguaje tiene consecuencias respecto de la ontología. Hilary Putnam ha sugerido la posibilidad de ser al mismo tiempo un realista y un relativista conceptual. Involucra consideraciones como las mencionadas, respecto de lógica y ontología. Su objetivo es el intento de hacer justicia a la realidad y al misterio de nuestro mundo de sentido común. Tomo esta tesis como una propuesta de trabajo. Me interesa pensar en cómo ofrecer algunos elementos de juicio para evaluar sus alcances. Para ello, examino la sugerencia de Putnam mediante un ejemplo construido con ese objetivo. Entiendo que se requerirán, al menos, dos esquemas conceptuales diferentes: al que surgiría de la lógica de orden 1, tal como la desarrolla Quine, y al que podría obtenerse a partir de la teoría de objetos no existentes de Castañeda. Se contará así con elementos de juicio más precisos que los habituales para evaluar las consecuencias que se seguirían para la ontología en caso de sostener ambos esquemas conceptuales, en consonancia con la propuesta de Putnam que se ha tomado como objetivo general del proyecto

Sobre la compatibilidad entre realismo y relativismo conceptual : Un exámen de la tesis de Putnam, desde un punto de vista lógico

Las indagaciones en la pregunta por lo que hay permiten distinguir a grandes rasgos entre dos enfoques: uno, el de los pensadores que entendieron que el tema a investigar era la naturaleza y estructura del mundo, y otro, el de aquellos quienes, al sostener que describir el mundo no es simplemente copiarlo, atendieron a lo que se llamó esquema conceptual: esto es, al marco conceptual cuya forma toman las descripciones del mundo. La situación se puede plantear como un dilema, ninguno de cuyos cuernos permite alentar esperanzas de avances bien fundados. O bien se pretende describir el mundo, tal como es, sin contemplar el hecho de que esa descripción incluye elecciones conceptuales propias de un sujeto, o bien se centra la investigación en los rasgos de el/los esquema/s conceptual/es imprescindibles para construir una descripción del mundo, imposibilitando, con ello, el acceso a la realidad tal como ésta es. En el siglo XX se cuenta con recursos de sistemas de lógica considerablemente más desarrollados y abarcadores (en sus posibilidades de aplicación) que los anteriores. Tales recursos brindan nuevas posibilidades de abordaje de la pregunta por lo que hay, no sólo por los ámbitos que se clarifican mediante ellos, sino también por el sustento que ofrecen para la reflexión filosófica los resultados obtenidos. Los avances producidos en el ámbito de la lógica en algo más de un siglo tuvieron variadas repercusiones en el enfoque y el tratamiento de distintas cuestiones filosóficas. Así, se ha echado mano a conceptos y recursos de lógica al considerar preguntas acerca de la estructura del mundo. Para la determinación de los componentes de la realidad se ha recurrido a la lógica, desde diversas posiciones filosóficas. Por ejemplo, se ha entendido que la lógica subyacente a la teoría científica brinda en algún sentido elementos para determinar la ontología (o para descartar la posibilidad de hacerlo, o para establecer qué función cumple la noción de ontología en la teoría científica). También, desde una óptica más amplia, se ha intentado mostrar que el uso del lenguaje tiene consecuencias respecto de la ontología. Hilary Putnam ha sugerido la posibilidad de ser al mismo tiempo un realista y un relativista conceptual. Involucra consideraciones como las mencionadas, respecto de lógica y ontología. Su objetivo es el intento de hacer justicia a la realidad y al misterio de nuestro mundo de sentido común. Tomo esta tesis como una propuesta de trabajo. Me interesa pensar en cómo ofrecer algunos elementos de juicio para evaluar sus alcances. Para ello, examino la sugerencia de Putnam mediante un ejemplo construido con ese objetivo. Entiendo que se requerirán, al menos, dos esquemas conceptuales diferentes: al que surgiría de la lógica de orden 1, tal como la desarrolla Quine, y al que podría obtenerse a partir de la teoría de objetos no existentes de Castañeda. Se contará así con elementos de juicio más precisos que los habituales para evaluar las consecuencias que se seguirían para la ontología en caso de sostener ambos esquemas conceptuales, en consonancia con la propuesta de Putnam que se ha tomado como objetivo general del proyecto

Pollen and macrofossils profiles and age determination from three cores in Northeastern Kansas, U.S.A.

Two marshes near Muscotah and Arrington, Atchison County, northeastern Kansas, yielded a pollen sequence covering the last 25,000 yrs of vegetation development. The earliest pollen spectra are comparable with surface pollen spectra from southern Saskatchewan and southeastern Manitoba and might indicate a rather open vegetation but with some pine, spruce, and birch as the most important tree species, with local stands of alder and willow. This type of vegetation changed about 23,000 yrs ago to a spruce forest, which prevailed in the region until at least 15,000 yrs ago. Because of a hiatus, the vegetation changes resulting in the spread of a mixed deciduous forest and prairie, which was present in the region from 11,000 to 9,000 yrs ago, remain unknown. Prairie vegetation, with perhaps a few trees along the valleys, covered the region until about 5,000 yrs ago, when a re-expansion of deciduous trees began in the lowlands.

(Table 1) Physical properties of basalts from DSDP Legs 69 and 70

Physical properties of basalts from Deep Sea Drilling Project Sites 504 and 505, south of the Costa Rica Rift, including wet-bulk density, water content, sonic velocity, and thermal conductivity, were measured on board D/V Glomar Challenger during Legs 69 and 70. The mean wet-bulk density is 2.90±0.06 g/cm**3, porosity 5.0±2.2%, sonic velocity 5.75±0.30 km/s, and thermal conductivity 1.67±0.09 W/m°K. Basalts from this young ocean crust (5.9 m.y.) have relatively low porosity and consequently high density and sonic velocity, as compared to average DSDP basalts. Some systematic trends in depth variation of physical properties were found: down to Core 40 in Hole 504B, grain densities were lower than those deeper in the hole, whereas porosity in the upper section was higher. This can be attributed either to differences in the flow type or in the nature of alteration of basalts at the different levels in the hole.

Diatom abundance in middle-to-late Pleistocene sediments of IODP Site 303-U1304

We examined diatom assemblages in a series of remarkable laminated diatomaceous ooze (LDO) horizons in the marine sediments from Integrated Ocean Drilling Program (IODP) Site U1304 to reconstruct the middle-to-late Pleistocene paleoceanographic evolution of the northern North Atlantic Ocean. Four confirmed diatom biohorizons combined with calcareous nannofossil and paleomagnetic stratigraphies established the chronological framework for the material. The planktonic, araphid, needle-like species Thalassiothrix longissima was the greatest contributor to the LDO facies. From the results of a principal component analysis using the percent abundances of 65 significant (p = 5%) diatom taxa, except for Tx. longissima, which was extremely dominant in almost all horizons observed, we identified two principal component (PC) axes. Taxa probably associated with the stratigraphic distribution of the major zonal marker Neodenticula seminae (ranging from 1.26 to 0.84 Ma in this ocean) loaded on PC1 with a high value. PC2 was related to the ocean surface temperature. The stratigraphic variability of the PC2 score indicated that switching between warm- and cold-water assemblages occurred concurrently with LDO deposition (or extreme Tx. longissima dominance) episodes in several horizons (particularly after 0.84 Ma), suggesting that the Subarctic Convergence (SAC) oceanic front passed over Site U1304 during Pleistocene glacial/interglacial cycles. Our floral evidence supports the model of nearly monospecific LDO formation caused by the enhanced physical accumulation of particular diatoms such as Tx. longissima. On the other hand, Nd. seminae, which probably contributes to spring phytoplankton blooms in the modern ocean, was present only between 1.26 and 0.84 Ma in this area. Thus, we infer that the main contributor of export flux in the regional annual primary production cycle would have shifted drastically from one of a spring phytoplankton bloom leader (Nd. seminae) to minor but mass dump assemblages (Tx. longissima etc.) in the mid-Pleistocene.

Late Cretaceous volcaniclastic rocks at DSDP Holes 74-525A and 74-528

Volcaniclastic rocks of Late Cretaceous age occur in four out of five sites (525, 527, 528, 529) drilled on the crest and the northwest flank of the Walvis Ridge during Leg 74. They are mostly interlayered with and overlie basement in the lowermost 10-100 m of the sedimentary section. Rocks from Holes 525A and 528 were studied megascopically and microscopically, by XRD, and XRF chemical analyses of whole-rock major and trace elements were undertaken. The dominant rock of Hole 528 volcaniclastics is a fine-grained (silt to fine sand), mostly matrix-bearing (partly matrix-rich) vitric "tuff," occurring as 5-110 cm thick, partly graded layers, some of which are distinctly bedded. Volcaniclastics of Hole 525A are generally richer in sanidine crystals. Most rocks contain some nonvolcanic clasts, chiefly foraminifers and lesser amounts of shallow-water fossil debris. Scoria shards, clasts of tachylite, and fine-grained basalts as well as chemical analyses suggest a basaltic to intermediate composition for most rocks of Hole 528, whereas volcaniclastics of Hole 525A are more silicic. The occurrence of tachylite and epiclastic, coarse-grained, basaltic clasts throughout the volcaniclastic sequence at Site 528 indicates shallow-water eruptions and perhaps even ocean island volcanism. The minor occurrence in Hole 528 of trachytic? pumice shards with phenocrysts of K-feldspar and the abundance of such shards in rocks from Hole 525A indicate Plinian eruptions characteristic of more mature stages of ocean island evolution. The sedimentary structures of volcaniclastic layers and their occurrence within deep sea calcareous oozes indicate a mass flow origin. Diagenetic alteration of the volcaniclastic rocks is pronounced, and four major stages of glass shard alteration are distinguished. Despite the effects of alteration and small-scale redistribution of elements and the admixture of nonvolcanic components, there were no drastic changes in the chemical composition of the rocks, except for pronounced increases in K and Rb and decreases in Ca and Fe. The basaltic volcaniclastic rocks very much resemble basement basalts in that they are moderately evolved tholeiites derived from an LIL-enriched mantle source with Zr/Nb ratios (Hole 528) of 5 to 6. This, in conjunction with the interbedding of volcaniclastic rocks and basement lavas, indicates contemporaneous seamount or island and basement volcanic activity involving magmas derived from similar sources.

Pollen profiles from three former lakes in the Lake Garda area

1. Late glacial and postglacial sediments from three former lakes in the Lake Garda area (Southern Alps) were investigated. 2. The pollen diagram from Bondone (1550 m) shows an older phase rich in NAP. A younger one corresponds with the Younger Dryas time according to two radiocarbon determinations. In the Preboreal no climatic deterioration could be found. 3. At first plants, which are nowadays typical for snow-ground, pioneer and dwarf shrub associations, immigrated into the surroundings of Bondone. In Alleröd times larch and pine appeared as the first trees. At the beginning of the Preboreal dense forest existed in that region. During the Alleröd timber line was at about 1500 m. 4. In the pollen diagrams from Saltarino (194 m) and Fiavè (654 m) an oldest period rich in NAP is followed by two stadial and two interstadial phases. Tree birches and larches immigrated during the oldest interstadial phase. 5. In the case of Saltarino and Fiavè only a preliminary dating could be made. A correlation seems to be possible with diagrams published by Zoller as well as with the diagram of Bondone. Discrepances in dating, which arise then, are discussed. According to the two possibilities of dating the youngest stadial is synchronous either with the so-called Piottino stadial or the Younger Dryas time. Consequently the oldest interstadial phase of Saltarino corresponds either with the Bölling or with a pre-Bölling interstadial. The last possibility seems to be more probable. 6. In the southern part of the Lake Garda area reforestation was preceded by a long shrub phase mainly with Juniperus. At about 650 m there was a period with Pinus mugo and only with a small amount of Juniperus before reforestation. A phase with Betula nana well known from areas north of the Alps could nowhere be found. 7. In the area under study larch appeared as the first tree. Lateron it has been the most important constituent of the forests near timber line. Birch, which plays an important role as a pioneer tree in Denmark - for instance at the transition of the pollen zones III/IV - as well as in Southern Germany during Bölling time, was of less importance at the southern border of the Alps. In that area the spreading of Pinus occurred very early causing dense forests. 8. During the last stadial phase (probably Younger Dryas time) dense forests with Pinus and Larix existed at 650 m. In the lower part of the Lake Garda area, however, both thermophilous trees as Quercus and herbs frequently occurred. This leads to the conclusion that during this time tree growth was limited by dryness in lower altitudes of the border of the Southern Alps. Pinus and Juniperus, however, do not show higher values in this period, a fact which cannot yet be explained. 9. A list of plants, which were found in the sediments, is compiled. Helodium lanatum, Dictamnus albus, Mercurialis cf. ovata, Buxus, Cerinthe cf. minor, Onosma, Anthericum and Asphodelus albus are findings, which are of special interest for the history of the flora of that region.