Thekopsora minima causes blueberry rust in south-eastern Queensland and northern New South Wales

The cause of blueberry rust in eastern Australia was determined by molecular and morphological analysis as Thekopsora minima.

Australia's newest quarantine for biological control

The paper describes the QC3 quarantine facility and supporting infrastructure which were purpose built for weed biological control at the Ecosciences Precinct. The quarantine is one of two new weed quarantine facilities in Australia and will service northern Australia. An account of the sharing philosophy between CSIRO and the Queensland Government and the necessity of working very closely with architects, project managers, builders and quarantine personnel is also given. This philosophy contributed to certification of the facility without any undue delays.

An inordinate fondness for Fusarium: Phylogenetic diversity of fusaria cultivated by ambrosia beetles in the genus Euwallacea on avocado and other plant hosts

Ambrosia beetle fungiculture represents one of the most ecologically and evolutionarily successful symbioses, as evidenced by the 11 independent origins and 3500 species of ambrosia beetles. Here we document the evolution of a clade within Fusarium associated with ambrosia beetles in the genus Euwallacea (Coleoptera: Scolytinae). Ambrosia Fusarium Clade (AFC) symbionts are unusual in that some are plant pathogens that cause significant damage in naive natural and cultivated ecosystems, and currently threaten avocado production in the United States, Israel and Australia. Most AFC fusaria produce unusual clavate macroconidia that serve as a putative food source for their insect mutualists. AFC symbionts were abundant in the heads of four Euwallacea spp., which suggests that they are transported within and from the natal gallery in mandibular mycangia. In a four-locus phylogenetic analysis, the AFC was resolved in a strongly supported monophyletic group within the previously described Cade 3 of the Fusarium solani species complex (FSSC). Divergence-time estimates place the origin of the AFC in the early Miocene similar to 21.2 Mya, which coincides with the hypothesized adaptive radiation of the Xyleborini. Two strongly supported clades within the AFC (Clades A and B) were identified that include nine species lineages associated with ambrosia beetles, eight with Euwallacea spp. and one reportedly with Xyleborus ferrugineus, and two lineages with no known beetle association. More derived lineages within the AFC showed fixation of the clavate (club-shaped) macroconidial trait, while basal lineages showed a mix of clavate and more typical fusiform macroconidia. AFC lineages consisted mostly of genetically identical individuals associated with specific insect hosts in defined geographic locations, with at least three interspecific hybridization events inferred based on discordant placement in individual gene genealogies and detection of recombinant loci. Overall, these data are consistent with a strong evolutionary trend toward obligate symbiosis coupled with secondary contact and interspecific hybridization. (C) 2013 Elsevier Inc. All rights reserved.

Panel of real-time PCRs for the multiplexed detection of two tomato-infecting begomoviruses and their cognate whitefly vector species

A new approach for the simultaneous identification of the viruses and vectors responsible for tomato yellow leaf curl disease (TYLCD) epidemics is presented. A panel of quantitative multiplexed real-time PCR assays was developed for the sensitive and reliable detection of Tomato yellow leaf curl virus-Israel (TYLCV-IL), Tomato leaf curl virus (ToLCV), Bemisia tabaci Middle East Asia Minor 1 species (MEAM1, B biotype) and B.tabaci Mediterranean species (MED, Q biotype) from either plant or whitefly samples. For quality-assurance purposes, two internal control assays were included in the assay panel for the co-amplification of solanaceous plant DNA or B.tabaci DNA. All assays were shown to be specific and reproducible. The multiplexed assays were able to reliably detect as few as 10 plasmid copies of TYLCV-IL, 100 plasmid copies of ToLCV, 500fg B.tabaci MEAM1 and 300fg B.tabaci MED DNA. Evaluated methods for routine testing of field-collected whiteflies are presented, including protocols for processing B.tabaci captured on yellow sticky traps and for bulking of multiple B.tabaci individuals prior to DNA extraction. This work assembles all of the essential features of a validated and quality-assured diagnostic method for the identification and discrimination of tomato-infecting begomovirus and B.tabaci vector species in Australia. This flexible panel of assays will facilitate improved quarantine, biosecurity and disease-management programmes both in Australia and worldwide.

A note on non-separable solutions of linear partial differential equation

A method has been presented for constructing non-separable solutions of homogeneous linear partial differential equations of the type F(D, D′)W = 0, where D = ∂/∂x, D′ = ∂/∂y, Image where crs are constants and n stands for the order of the equation. The method has also been extended for equations of the form Φ(D, D′, D″)W = 0, where D = ∂/∂x, D′ = ∂/∂y, D″ = ∂/∂z and Image As illustration, the method has been applied to obtain nonseparable solutions of the two and three dimensional Helmholtz equations.

Uromycladium falcatarium sp. nov., the cause of gall rust on Paraserianthes falcataria in south-east Asia

The gall rusts on Acacia spp. and Paraserianthes falcataria are caused by species of Uromycladium. Morphology and a phylogenetic analysis of four loci from ribosomal (SSU, ITS, LSU) and mitochondrial (CO3) DNA, showed that the rust on P. falcataria differed from U. tepperianum. Uromycladium falcatarium sp. nov. is described to accommodate this taxon, which can be differentiated from other species of Uromycladium by teliospore wall morphology, host genus and DNA sequence data.

Fungal Planet description sheets: 371-399

Novel species of fungi described in the present study include the following from Australia: Neoseptorioides eucalypti gen. & sp. nov. from Eucalyptus radiata leaves, Phytophthora gondwanensis from soil, Diaporthe tulliensis from rotted stem ends of Theobroma cacao fruit, Diaporthe vawdreyi from fruit rot of Psidium guajava, Magnaporthiopsis agrostidis from rotted roots of Agrostis stolonifera and Semifissispora natalis from Eucalyptus leaf litter. Furthermore, Neopestalotiopsis egyptiaca is described from Mangifera indica leaves (Egypt), Roussoella mexicana from Coffea arabica leaves (Mexico), Calonectria monticola from soil (Thailand), Hygrocybe jackmanii from littoral sand dunes (Canada), Lindgomyces madisonensis from submerged decorticated wood (USA), Neofabraea brasiliensis from Malus domestica (Brazil), Geastrum diosiae from litter (Argentina), Ganoderma wiiroense on angiosperms (Ghana), Arthrinium gutiae from the gut of a grasshopper (India), Pyrenochaeta telephoni from the screen of a mobile phone (India) and Xenoleptographium phialoconidium gen. & sp. nov. on exposed xylem tissues of Gmelina arborea (Indonesia). Several novelties are introduced from Spain, namely Psathyrella complutensis on loamy soil, Chlorophyllum lusitanicum on nitrified grasslands (incl. Chlorophyllum arizonicum comb. nov.), Aspergillus citocrescens from cave sediment and Lotinia verna gen. & sp. nov. from muddy soil. Novel foliicolous taxa from South Africa include Phyllosticta carissicola from Carissa macrocarpa, Pseudopyricularia hagahagae from Cyperaceae and Zeloasperisporium searsiae from Searsia chirindensis. Furthermore, Neophaeococcomyces is introduced as a novel genus, with two new combinations, N. aloes and N. catenatus. Several foliicolous novelties are recorded from La Réunion, France, namely Ochroconis pandanicola from Pandanus utilis, Neosulcatispora agaves gen. & sp. nov. from Agave vera-cruz, Pilidium eucalyptorum from Eucalyptus robusta, Strelitziana syzygii from Syzygium jambos (incl. Strelitzianaceae fam. nov.) and Pseudobeltrania ocoteae from Ocotea obtusata (Beltraniaceae emend.). Morphological and culture characteristics along with ITS DNA barcodes are provided for all taxa.

A co-evolutionary relationship exists between Endoraecium (Pucciniales) and its Acacia hosts in Australia

Endoraecium is a genus of rust fungi that infects several species of Acacia in Australia, South-East Asia and Hawaii. This study investigated the systematics of Endoraecium from 55 specimens in Australia based on a combined morphological and molecular approach. Phylogenetic analyses were conducted on partitioned datasets of loci from ribosomal and mitochondrial DNA. The recovered molecular phylogeny supported a recently published taxonomy based on morphology and host range that divided Endoraecium digitatum into five species. Spore morphology is synapomorphic and there is evidence Endoraecium co-evolved with its Acacia hosts. The broad host ranges of E. digitatum, E. parvum, E. phyllodiorum and E. violae-faustiae are revised in light of this study, and nine new species of Endoraecium are described from Australia based on host taxonomy, morphology and phylogenetic concordance.

The host specificity and climatic suitability of the gall flyCecidochares connexa(Diptera: Tephritidae), a potential biological control agent for Chromolaena odorata(Asteraceae) in Australia

The gall fly Cecidochares connexa (Diptera: Tephritidae) is a potential biological control agent for Chromolaena odorata in Australia. Its host specificity was determined against 18 species in the tribe Eupatorieae (Family Asteraceae) in which C. odorata belongs, in quarantine in Brisbane, Australia. Oviposition occurred and flies developed on only C. odorata and Praxelis clematidea, both of which are in the subtribe Praxelinae. P. clematidea is considered a weed outside tropical America. In both multiple-species-minus-C. odorata choice tests and single-species no-choice tests, the mean number of galls/plant was significantly greater on C. odorata (48 and 41, respectively) than on P. clematidea (2 and 9, respectively). There were also significantly more adults emerging from C. odorata (mean 129 and 169, respectively) in the two types of tests than from P. clematidea (1 and 8, respectively). Paired choice, multiple generation (continuation) and time dependent tests further clarified the extent that C. connexa could develop on P. clematidea. In these tests, the mean number of galls formed and the mean number of emerging adults were consistently less for P. clematidea than C. odorata and populations of C. connexa could not be maintained on P. clematidea. Galls were not seen on any other plant species tested. This study supports the results of host specificity testing conducted in seven other countries and confirms that C. connexa poses little risk to other plant species in Australia. C. connexa has been released in 10 countries and an application seeking approval to release in Australia has been submitted to the Australian Government.

Environmental effects of thermal and radioactive discharges from nuclear power plants in the boreal brackish-water conditions of the northern Baltic Sea

During recent decades, thermal and radioactive discharges from nuclear power plants into the aquatic environment have become the subject of lively debate as an ecological concern. The target of this thesis was to summarize the large quantity of results obtained in extensive monitoring programmes and studies carried out in recipient sea areas off the Finnish nuclear power plants at Loviisa and Olkiluoto during more than four decades. The Loviisa NPP is located on the coast of the Gulf of Finland and Olkiluoto NPP on that of the Bothnian Sea. The state of the Gulf of Finland is clearly more eutrophic; the nutrient concentrations in the surface water are about 1½ 2 times higher at Loviisa than at Olkiluoto, and the total phosphorus concentrations still increased in both areas (even doubled at Loviisa) between the early 1970s and 2000. Thus, it is a challenge to distinguish the local effects of thermal discharges from the general eutrophication process of the Gulf of Finland. The salinity is generally low in the brackish-water conditions of the northern Baltic Sea, being however about 1 higher at Olkiluoto than at Loviisa (the salinity of surface water varying at the latter from near to 0 in early spring to 4 6 in late autumn). Thus, many marine and fresh-water organisms live in the Loviisa area close to their limit of existence, which makes the biota sensitive to any additional stress. The characteristics of the discharge areas of the two sites differ from each other in many respects: the discharge area at Loviisa is a semi-enclosed bay in the inner archipelago, where the exchange of water is limited, while the discharge area at Olkiluoto is more open, and the exchange of water with the open Bothnian Sea is more effective. The effects of the cooling water discharged from the power plants on the temperatures in the sea were most obvious in winter. The formation of a permanent ice cover in the discharge areas has been delayed in early winter, and the break-up of the ice occurs earlier in spring. The prolonging of the growing season and the disturbance of the overwintering time, in conditions where the biota has adjusted to a distinct rest period in winter, have been the most significant biological effects of the thermal pollution. The soft-bottom macrofauna at Loviisa has deteriorated to the point of almost total extinction at many sampling stations during the past 40 years. A similar decline has been reported for the whole eastern Gulf of Finland. However, the local eutrophication process seems to have contributed into the decline of the zoobenthos in the discharge area at Loviisa. Thermal discharges have increased the production of organic matter, which again has led to more organic bottom deposits. These have in turn increased the tendency of the isolated deeps to a depletion of oxygen, and this has further caused strong remobilization of phosphorus from the bottom sediments. Phytoplankton primary production and primary production capacity doubled in the whole area between the late 1960s and the late 1990s, but started to decrease a little at the beginning of this century. The focus of the production shifted from spring to mid- and late summer. The general rise in the level of primary production was mainly due to the increase in nutrient concentrations over the whole Gulf of Finland, but the thermal discharge contributed to a stronger increase of production in the discharge area compared to that in the intake area. The eutrophication of littoral vegetation in the discharge area has been the most obvious, unambiguous and significant biological effect of the heated water. Myriophyllum spicatum, Potamogeton perfoliatus and Potamogeton pectinatus, and vigorous growths of numerous filamentous algae as their epiphytes have strongly increased in the vicinity of the cooling water outlet, where they have formed dense populations in the littoral zone in late summer. However, the strongest increase of phytobenthos has extended only to a distance of about 1 km from the outlet, i.e., the changes in vegetation have been largest in those areas that remain ice-free in winter. Similar trends were also discernible at Olkiluoto, but to a clearly smaller extent, which was due to the definitely weaker level of background eutrophy and nutrient concentrations in the Bothnian Sea, and the differing local hydrographical and biological factors prevailing in the Olkiluoto area. The level of primary production has also increased at Olkiluoto, but has remained at a clearly lower level than at Loviisa. In spite of the analogous changes observed in the macrozoobenthos, the benthic fauna has remained strong and diversified in the Olkiluoto area. Small amounts of local discharge nuclides were regularly detected in environmental samples taken from the discharge areas: tritium in seawater samples, and activation products, such as 60Co, 58Co, 54Mn, 110mAg, 51Cr, in suspended particulate matter, bottom sediments and in several indicator organisms (e.g., periphyton and Fucus vesiculosus) that effectively accumulate radioactive substances from the medium. The tritium discharges and the consequent detection frequency and concentrations of tritium in seawater were higher at Loviisa, but the concentrations of the activation products were higher at Olkiluoto, where traces of local discharge nuclides were also observed over a clearly wider area, due to the better exchange of water than at Loviisa, where local discharge nuclides were only detected outside Hästholmsfjärden Bay quite rarely and in smaller amounts. At the farthest, an insignificant trace amount (0.2 Bq kg-1 d.w.) of 60Co originating from Olkiluoto was detected in Fucus at a distance of 137 km from the power plant. Discharge nuclides from the local nuclear power plants were almost exclusively detected at the lower trophic levels of the ecosystems. Traces of local discharge nuclides were very seldom detected in fish, and even then only in very low quantities. As a consequence of the reduced discharges, the concentrations of local discharge nuclides in the environment have decreased noticeably in recent years at both Loviisa and Olkiluoto. Although the concentrations in environmental samples, and above all, the discharge data, are presented as seemingly large numbers, the radiation doses caused by them to the population and to the biota are very low, practically insignificant. The effects of the thermal discharges have been more significant, at least to the wildlife in the discharge areas of the cooling water, although the area of impact has been relatively small. The results show that the nutrient level and the exchange of water in the discharge area of a nuclear power plant are of crucial importance.

Whole-genome sequencing identifies EN1 as a determinant of bone density and fracture

The extent to which low-frequency (minor allele frequency (MAF) between 1-5%) and rare (MAF d with common genetic variants, as well as rare, population-specific, coding variants. Here we identify novel non-coding genetic variants with large effects on BMD (ntotal = 53,236) and fracture (ntotal = 508,253) in individuals of European ancestry from the general population. Associations for BMD were derived from whole-genome sequencing (n = 2,882 from UK10K (ref. 10); a population-based genome sequencing consortium), whole-exome sequencing (n = 3,549), deep imputation of genotyped samples using a combined UK10K/1000 Genomes reference panel (n = 26,534), and de novo replication genotyping (n = 20,271). We identified a low-frequency non-coding variant near a novel locus, EN1, with an effect size fourfold larger than the mean of previously reported common variants for lumbar spine BMD (rs11692564(T), MAF = 1.6%, replication effect size = +0.20 s.d., Pmeta = 2 x 10(-14)), which was also associated with a decreased risk of fracture (odds ratio = 0.85; P = 2 x 10(-11); ncases = 98,742 and ncontrols = 409,511). Using an En1(cre/flox) mouse model, we observed that conditional loss of En1 results in low bone mass, probably as a consequence of high bone turnover. We also identified a novel low-frequency non-coding variant with large effects on BMD near WNT16 (rs148771817(T), MAF = 1.2%, replication effect size = +0.41 s.d., Pmeta = 1 x 10(-11)). In general, there was an excess of association signals arising from deleterious coding and conserved non-coding variants. These findings provide evidence that low-frequency non-coding variants have large effects on BMD and fracture, thereby providing rationale for whole-genome sequencing and improved imputation reference panels to study the genetic architecture of complex traits and disease in the general population.

Pilkahduksia Pilkkeestä – tutkimus ikääntyvien päihteidenkäyttäjien päivätoimintaryhmistä

Tutkimuskohteenani ovat Helsingin Diakonissalaitoksen Pilke-projektin päivätoimintaryhmät ikääntyville päihteidenkäyttäjille. Helsingin Diakonissalaitoksen Pilke-projekti on osa Sininauhaliiton Liika on aina liikaa – ikääntyminen ja alkoholi -hanketta ja sitä rahoittaa Raha-automaattiyhdistys. Idea tutkimuksen tekoon nousi Liika on aina liikaa – ikääntyminen ja alkoholi -hankkeen tutkimustarpeiden myötä, tarpeesta saada kuuluviin yhden osahankkeen asiakkaiden ääni ja nostaa esiin heidän näkemyksensä ja kokemuksensa ryhmätoiminnasta, johon he osallistuvat, ja jota ei ole tutkittu vielä. Yhtenä perusteluna tutkimuksen tekemiselle on myös se, että aihe on uusi ja sitä ei ole juurikaan tutkittu. Tutkimusotteeni on etnografinen. Olen havainnoinut kolmea, Helsingin Diakonissalaitoksen eri tiloissa kokoontuvaa Pilke-ryhmää reilun puolen vuoden ajan. Tämän lisäksi olen haastatellut ryhmien jäseniä ryhmähaastattelun keinoin. Tutkimusnäkökulmaani olen laajentanut koskemaan myös ohjaajien työtä, koska pidän heidän työnsä näkyväksi tekemistä tärkeänä. Analyysissä yhdistän etnografisen aineiston temaattista luentaa ja diskurssianalyyttisempää otetta kiinnittäen huomiota puheella tuotettuihin ja puheen tuottamiin merkityksiin, vuorovaikutukseen keskustelijoiden välillä sekä identiteetin rakentumiseen puheessa. Tutkimuksessa pyrin kuvaamaan ja ymmärtämään ikääntyvien päihteidenkäyttäjien ryhmätoimintaa ja sen merkitystä ikääntyville sekä sitä, miten ryhmään löydytään. Ryhmähaastatteluissa kiinnostukseni kohdistuu etenkin siihen, miten ikääntyvät kokevat Pilke-ryhmätoiminnan ja millaisia määrittelyjä he itsestään ja suhteestaan ryhmätoimintaan tai alkoholiin antavat. Tuon esiin myös sitä, millaisiin haasteisiin tutkija voi törmätä tutkiessa ikääntyneitä päihteidenkäyttäjiä. Pohdin esimerkiksi afaattisesti puhuvien ihmisten haastattelemista ryhmähaastattelun keinoin sekä miksi havainnointi on mielestäni hyvä tapa tutkia ikääntyneitä päihteidenkäyttäjiä. Tulo Pilkkeeseen alkaa etsivästä työstä. Verkostojen yhteistyöllä ryhmiin päätyvät sellaiset ikääntyvät, joista suurin osa ei olisi kotonaan aktiivisten eläkeläisten harrastuspiireissä, koska niissä ei ole totuttu käymään ja sosiaalinen elämä on rajoittunut esimerkiksi lähiöravintolaan. Puhutaan haastavanakin pidetystä vähemmistöstä ikääntyneiden joukossa. Alkoholia on käytetty jo pitkään, tai sitä on ryhdytty käyttämään runsaasti vasta iäkkäänä. Pilkkeeseen löytyvistä ikääntyvistä varsin suuri osa kuitenkin kiinnittyy ryhmään. Tähän syynä ovat uusien ihmiskontaktien saamisen tärkeys, ohjaajien persoona, keskustelumahdollisuus ja mahdollisuus tehdä käsillä jotain, mitä kenties ei koskaan tulisi kotona tehtyä. Kynnys osallistumiseen on matala ja vaatimuksia elämäntapoja muuttamiselle ei ole. Pilkkeen merkitys siihen osallistuville on tulosteni mukaan suuri. Pilke katkaisee usein yksinäiseksikin koettua arkea ja muut ryhmässä käyvät koetaan tärkeiksi. Pilke tarjoaa mahdollisuuden jakaa ajatuksiaan ja omaa elämäntarinaansa. Huumori kantaa Pilke-tapaamisia. Myös käsillä tekeminen koetaan tärkeäksi ja sen huomaaminen, että tekemisen taito on tallella, voimaannuttaa. Pilke luo uudenlaista järjestystä elämään ja sen myötä myös alkoholinkäyttö osalla vähenee. Etenkin pitkäaikaisille jäsenille Pilkkeen voi sanoa muodostuvan kiinnipitäväksi ympäristöksi, joka on tutkimukseni keskeinen, alun perin D.W. Winnicottin käyttämä käsite.

On Finding the Natural Number of Topics with Latent Dirichlet Allocation: Some Observations

It is important to identify the ``correct'' number of topics in mechanisms like Latent Dirichlet Allocation(LDA) as they determine the quality of features that are presented as features for classifiers like SVM. In this work we propose a measure to identify the correct number of topics and offer empirical evidence in its favor in terms of classification accuracy and the number of topics that are naturally present in the corpus. We show the merit of the measure by applying it on real-world as well as synthetic data sets(both text and images). In proposing this measure, we view LDA as a matrix factorization mechanism, wherein a given corpus C is split into two matrix factors M-1 and M-2 as given by C-d*w = M1(d*t) x Q(t*w).Where d is the number of documents present in the corpus anti w is the size of the vocabulary. The quality of the split depends on ``t'', the right number of topics chosen. The measure is computed in terms of symmetric KL-Divergence of salient distributions that are derived from these matrix factors. We observe that the divergence values are higher for non-optimal number of topics - this is shown by a `dip' at the right value for `t'.

Pilkahduksia Pilkkeestä : tutkimus ikääntyvien päihteidenkäyttäjien päivätoimintaryhmistä

Tutkimuskohteenani ovat Helsingin Diakonissalaitoksen Pilke-projektin päivätoimintaryhmät ikääntyville päihteidenkäyttäjille. Helsingin Diakonissalaitoksen Pilke-projekti on osa Sininauhaliiton Liika on aina liikaa – ikääntyminen ja alkoholi -hanketta ja sitä rahoittaa Raha-automaattiyhdistys. Idea tutkimuksen tekoon nousi Liika on aina liikaa – ikääntyminen ja alkoholi -hankkeen tutkimustarpeiden myötä, tarpeesta saada kuuluviin yhden osahankkeen asiakkaiden ääni ja nostaa esiin heidän näkemyksensä ja kokemuksensa ryhmätoiminnasta, johon he osallistuvat, ja jota ei ole tutkittu vielä. Yhtenä perusteluna tutkimuksen tekemiselle on myös se, että aihe on uusi ja sitä ei ole juurikaan tutkittu. Tutkimusotteeni on etnografinen. Olen havainnoinut kolmea, Helsingin Diakonissalaitoksen eri tiloissa kokoontuvaa Pilke-ryhmää reilun puolen vuoden ajan. Tämän lisäksi olen haastatellut ryhmien jäseniä ryhmähaastattelun keinoin. Tutkimusnäkökulmaani olen laajentanut koskemaan myös ohjaajien työtä, koska pidän heidän työnsä näkyväksi tekemistä tärkeänä. Analyysissä yhdistän etnografisen aineiston temaattista luentaa ja diskurssianalyyttisempää otetta kiinnittäen huomiota puheella tuotettuihin ja puheen tuottamiin merkityksiin, vuorovaikutukseen keskustelijoiden välillä sekä identiteetin rakentumiseen puheessa. Tutkimuksessa pyrin kuvaamaan ja ymmärtämään ikääntyvien päihteidenkäyttäjien ryhmätoimintaa ja sen merkitystä ikääntyville sekä sitä, miten ryhmään löydytään. Ryhmähaastatteluissa kiinnostukseni kohdistuu etenkin siihen, miten ikääntyvät kokevat Pilke-ryhmätoiminnan ja millaisia määrittelyjä he itsestään ja suhteestaan ryhmätoimintaan tai alkoholiin antavat. Tuon esiin myös sitä, millaisiin haasteisiin tutkija voi törmätä tutkiessa ikääntyneitä päihteidenkäyttäjiä. Pohdin esimerkiksi afaattisesti puhuvien ihmisten haastattelemista ryhmähaastattelun keinoin sekä miksi havainnointi on mielestäni hyvä tapa tutkia ikääntyneitä päihteidenkäyttäjiä. Tulo Pilkkeeseen alkaa etsivästä työstä. Verkostojen yhteistyöllä ryhmiin päätyvät sellaiset ikääntyvät, joista suurin osa ei olisi kotonaan aktiivisten eläkeläisten harrastuspiireissä, koska niissä ei ole totuttu käymään ja sosiaalinen elämä on rajoittunut esimerkiksi lähiöravintolaan. Puhutaan haastavanakin pidetystä vähemmistöstä ikääntyneiden joukossa. Alkoholia on käytetty jo pitkään, tai sitä on ryhdytty käyttämään runsaasti vasta iäkkäänä. Pilkkeeseen löytyvistä ikääntyvistä varsin suuri osa kuitenkin kiinnittyy ryhmään. Tähän syynä ovat uusien ihmiskontaktien saamisen tärkeys, ohjaajien persoona, keskustelumahdollisuus ja mahdollisuus tehdä käsillä jotain, mitä kenties ei koskaan tulisi kotona tehtyä. Kynnys osallistumiseen on matala ja vaatimuksia elämäntapoja muuttamiselle ei ole. Pilkkeen merkitys siihen osallistuville on tulosteni mukaan suuri. Pilke katkaisee usein yksinäiseksikin koettua arkea ja muut ryhmässä käyvät koetaan tärkeiksi. Pilke tarjoaa mahdollisuuden jakaa ajatuksiaan ja omaa elämäntarinaansa. Huumori kantaa Pilke-tapaamisia. Myös käsillä tekeminen koetaan tärkeäksi ja sen huomaaminen, että tekemisen taito on tallella, voimaannuttaa. Pilke luo uudenlaista järjestystä elämään ja sen myötä myös alkoholinkäyttö osalla vähenee. Etenkin pitkäaikaisille jäsenille Pilkkeen voi sanoa muodostuvan kiinnipitäväksi ympäristöksi, joka on tutkimukseni keskeinen, alun perin D.W. Winnicottin käyttämä käsite.

Influencia de la densidad de siembra y presencia de malezas en la incidencia del achaparramiento del maíz (Zea mays L.)

En el presente trabajo se investigó el efecto de los factores maleza, variedad y densidad y su interacción sobre la Incidencia del achaparramiento y la dinámica poblacional del insecto vector Dalbulus maidis (D & W), en el cultivo del maíz. El estudio fue establecido durante la época seca, Noviembre de 1987 en el Centro Nacional de Granos Básicos, San Cristóbal, Managua, Región III. El efecto de los tres factores se evaluó con análisis de varianza (ANDEVA) y separación de medias (tukey 0.05), a través de la correlación se estudió la asociación que hay entre la enfermedad y la población del insecto. Los síntomas presentados por las plantas en el campo se iniciaron con franjas cloróticas en la base de las hojas jóvenes seguidos por decoloraciones rojizas en el extremo de las hojas viejas, además de estos síntomas se observaron plantas de entrenudos cortos, con mazorcas pequeñas y deformes. El grado de incidencia de la enfermedad en el campo, se vio favorecido por lluvias escasas durante el ciclo del cultivo, con una precipitación promedio mensual de 66.22 mm, el riego programado se interrumpió durante el período de establecimiento del cultivo. El tratamiento que contempló malezas hasta los 28 días después de la siembra, variedad tolerante y densidad alta (M28v tPa), demostró tener influencia sobre el control del achaparramiento, ya que presentó un menor porcentaje de la enfermedad, siendo este de 26%, contra el tratamiento en que se controló maleza y se sembró variedad susceptible, densidad baja (M0VsPa ) obteniéndose el 74% de incidencia. Finalmente se determinó que el tratamiento afectado más severamente por esta enfermedad antes de la floración llegó a obtener un promedio de poco más de 500 kg/ha.