Ovule ontogeny of Tabebuia pulcherrima Sandwith (Bignoniaceae): megasporogenesis and integument development

The ovule of Tabebuia pulcherrima is anatropous, unitegmic and tenuinucellate. The nucellus shows a trizonate structural organization. The integument is initiated by periclinal divisions in the dermal layer (zone I), around the base of the archesporium. Subsequently, cells derived from the subdermal layer (zone II) start to push the dermal cells, so that they shift toward the micropylar region. The archesporial cell differentiates directly into the megaspore mother cell, undergoes meiosis, and originates a linear tetrad of megaspores. The mature embryo sac mother cell is elongated, possess a conspicuous central nucleus, and a characteristic bipolar vacuome with fibrous-granulated content. The inner cell layers of the integument differentiate into an amyloplast-rich endothelium. Patterns of callose deposition in the tetrad and selection of the functional megaspore, as well as the taxonomic value of some characters are discussed.

Primary and secondary development of Cyperus giganteus Vahl rhizome (Cyperaceae)

In Cyperus giganteus, like in other Monocotyledoneae, the protoderm, procambium, fundamental meristem and primary thickening meristem (PTM) are differentiated from the rhizome promeristem. The PTM produces the inner cortical parenchyma, endodermis, pericycle and amphivasal vascular bundles, which are formed by the procambium too. After the primary body differentiates, cellular divisions continue only in the pericycle, and originate an irregular vascular system with vessel elements shorter and more branched than those found in the primary growth. This change of activity in the pericycle defines a secondary growth, where the secondary thickening meristem (STM) is the pericycle itself.

Effect of abscisic acid on the mobilisation of galactomannan and embryo development of Sesbania virgata (Cav.) Pers. (Leguminosae - Faboideae)

Galactomannans (GM) are storage cell wall polysaccharides present in endospermic seeds of legumes. They are thought to be storage polymers, since it has been observed for a few species (among them Sesbania virgata) that they are completely broken down after germination and their products are transferred to the growing embryo. We examined the effect of 10-4 M abscisic acid (ABA) on the degradation of galactomannan in isolated endosperms and intact seeds of S. virgata. We found that after seed germination the initial embryo growth was retarded. Ultrastructural analysis showed that the embryo is completely surrounded by an endosperm which displays very thick galactomannan-containing cell walls. Although an inhibitory effect has been observed on the increase of fresh mass of the embryo, the effect of ABA on the dry mass was weaker and transitory (from 48 to 96 h). Endosperm dry mass and galactomannan degradation were significantly inhibited and the activity of alpha-galactosidase was strongly affected. The addition of ABA before and/or after the start of mobilisation in intact seeds or isolated endosperms, showed that whereas addition before mobilisation did not affect dry mass decrease in intact seeds, it was strongly affected in isolated endosperms. On the other hand, whereas it affected embryo fresh mass increase in intact seeds, but not in isolated embryos, no significant effect was observed on dry mass. These results suggest that ABA affects galactomannan degradation and by doing so, prevents water absorption by the embryo, rather than affect its dry mass. As ABA has been detected in the endosperm of seeds of S. virgata, it is proposed that it probably acts as a modulator of galactomannan mobilisation and consequently synchronises it with early growth of the embryo.

Megaspore germination and initial development of Regnellidium diphyllum Lindman (Pteridophyta, Marsileaceae) sporophytes in the presence of cadmium

Regnellidium diphyllum has its distribution restricted to Southern Brazil and adjoining localities in Uruguay and Argentina. Currently it is on the list of threatened species of Rio Grande do Sul. The conversion of wetlands into agricultural areas or soil contamination by the introduction of waste products and fertilizers may compromise the establishment and survival of this species. Among the pollutants are heavy metals, such as cadmium (Cd). Megaspores were germinated in liquid culture medium, with concentrations 0 (control), 0.39; 0.78; 1.56; 3.12; 6.25; 12.5; 25; 50 and 100 mg L-1 of Cd, starting from a standard solution of Titrisol® at 1000 mg L-1. The increase of Cd in the growth medium to 50 mg L-1 resulted in low germinability (58%), and no germination was observed on 100 mg L-1. In apomictical sporophytes, the growth of primary root and leaf was significantly reduced and no secondary leaf was formed at Cd concentrations of 12.5 and higher than this. The results indicated that R. diphyllum is tolerant to the presence of Cd up to considerably higher concentrations (0.78 mg L-1) than that normally found in unpolluted aquatic ecosystems (0.01 mg L-1), although the sensitivity to higher concentrations might endanger the establishment and permanence of this species in habitats exposed to contamination with this metal.

The board of directors as a part of family business governance – multilevel participation and board development

In this study, I examine the board of directors as a part of family business governance. Both boards and governance have increased their attractiveness as a research topic lately. Research on boards has concentrated mostly on the study of different board attributes, like composition, and the relationship of these attributes to the firm’s performance. Family business governance studies are criticized for ignoring the multifaceted needs of companies. More research observing the context and contingencies affecting the governance and board of directors is needed. The objective of this study is to clarify: 1) how the board participates in family business governance, and 2) how the board develops along with the firm’s and family’s development. The study is implemented as qualitative research, and the longitudinal process approach has been used as it provides the opportunity to examine development in context. Selection criteria for the two cases selected for this study are: active board of directors, at least one implemented succession, and interviewees available from two generations and from different positions in the firm. The data consists of interviews and secondary data, and it is collected from different data sources. The analysis was done selecting first some critical events from both cases to closer examination, and analysing them by using content analysis technique. Several conclusions were drawn basing on the findings. First, the family business board participates in the firm’s activities much more widely than it is customary to think. Second, the family business board is not a static part of the business, but it develops and it has to develop for different reasons. Third, ownership is not only the basis for the board’s activities or existence, but the relationship between the board and ownership is two-way. The board contributes to a large extent to the ownership decisions, and in this way to the management of ownership. Fourth, according to the cases, the board has many unrecognized possibilities to facilitate succession in family firms.

Biochemical profile of amniotic fluid for the assessment of fetal and renal development

Creatinine plays a key role in the function and maturation of fetal kidneys throughout pregnancy. It is important to identify other markers that may help in the diagnosis of renal dysfunction. Our aim was to determine the profile of and the correlation between biochemical markers to be used to assess renal function and maturation of the fetus in the amniotic fluid during pregnancy and to determine the distribution of normal values for creatinine, N-acetyl-ß-D-glucosaminidase (NAG), ß2-microglobulin, glucose, urea, sodium, potassium, phosphorus, calcium, uric acid, albumin, and osmolality in three gestational age groups. This was a cross-section study that assessed 115 samples of amniotic fluid during three different periods of pregnancy, i.e., 13 to 20, 27 to 34, and 36 to 42 weeks. Concentrations of creatinine, NAG, urea, potassium and uric acid increased during pregnancy (P<0.05). ß2-Microglobulin, glucose, sodium, phosphorus, calcium, and albumin concentration and osmolality decreased (P<0.05), whereas ß2-microglobulin, glucose and uric acid presented significant correlations with gestational age and creatinine, respectively (r>0.6, P<0.05). Urea, potassium and phosphorus showed mild correlations with both (r>0.5, P<0.05). NAG, sodium, albumin and osmolality did not show significant correlations (r<0.5, P<0.05). These tests confirmed the important role of creatinine in terms of correlation with gestational age. ß2-Microglobulin, glucose and uric acid were significant as markers of function and maturation of fetal kidneys, whereas NAG did not demonstrate a useful role for the assessment of renal maturation.

Work and non-work : on work and meaning

I den politiska retoriken florerar debattinlägg om arbetslivet, och målsättningen är för det mesta att så många som möjligt ska arbeta så länge som möjligt. Att skapa jobb och minimera arbetslösheten ses som de främsta utmaningarna. På ett individuellt plan beskrivs arbete ofta som personligt självförverkligande eller som en nödvändig form av inkomst som kräver att livet struktureras enligt behovet av sysselsättning. I avhandlingen diskuteras hur de här till synes självklara rollerna som arbete spelar kan sägas neutralisera arbete. Med detta menas att kontroverser kring arbetets mening åsidosätts så att politiskt och etiskt grundläggande frågor om ett gott liv och mänskliga gemenskaper inte ges plats. Genom att gå i dialog med kritiska tänkare som Hannah Arendt, André Gorz, Kathi Weeks, Karl Marx och Richard Sennett diskuteras riskerna med att behandla arbete som en resurs, ett gemensamt samhällsprojekt eller individuellt självförverkligande. Vad är nödvändigt arbete? Vad innebär det att arbete är en vara? Vad är problemet med fragmentering av arbete? Det sägs ofta att arbete har blivit alltmer gränslöst – är detta något positivt eller negativt? Utifrån sådana frågor tar avhandlingen fasta på spänningar i arbetets roll i våra liv och i samhället. Genom att artikulera spänningar utmanas en neutralisering av arbetets etiskt och politiskt brännbara dimensioner. Avhandlingen syftar därmed till att lyfta fram ständigt pågående sätt att ifrågasätta och reflektera kring arbetets mening.

Inventive design and product development of a mechanical element

The thesis is dedicated to enhancement and development of a Mechanism in Company X in order to increase its key parameters and approve its workability. Current Mechanism model is described in details. The basis of various analysis, models and theories that are reflecting the working process of the Mechanism are included in the thesis. According to these three directions of enhancements are chosen: from mechanical, tribological and conceptual points of view. As the result the list of improvements is presented. The new models of Mechanism are built. The efficiency and lifetime value are obtained in accordance with corresponding estimations. The comparative analysis confirms the necessity of conducted changes. Recommendations for the Company X specialists are represented in the thesis. Proposals for deeper research are also suggested.

How computer programmers work : understanding software development in practise

Hur arbetar en framgångsrik programmerare? Uppgifterna att programmera datorspel och att programmera industriella, säkerhetskritiska system verkar tämligen olika. Genom en noggrann empirisk undersökning jämför och kontrasterar avhandlingen dessa två former av programmering och visar att programmering innefattar mer än teknisk förmåga. Med utgångspunkt i hermeneutisk och retorisk teori och med hjälp av både kulturvetenskap och datavetenskap visar avhandlingen att programmerarnas tradition och värderingar är grundläggande för deras arbete, och att båda sorter av programmering kan uppfattas och analyseras genom klassisk texttolkningstradition. Dessutom kan datorprogram betraktas och analyseras med hjälp av klassiska teorier om talproduktion i praktiken - program ses då i detta sammanhang som ett slags yttranden. Allt som allt förespråkar avhandlingen en återkomst till vetenskapens grunder, vilka innebär en ständig och oupphörlig cyklisk rörelse mellan att erfara och att förstå. Detta står i kontrast till en reduktionistisk syn på vetenskapen, som skiljer skarpt mellan subjektivt och objektivt, och på så sätt utgår från möjligheten att uppnå fullständigt vetande. Ofullständigt vetande är tolkandets och hermeneutikens domän. Syftet med avhandlingen är att med hjälp av exempel demonstrera programmeringens kulturella, hermeneutiska och retoriska natur.

Effect of conditioned medium of mesenchymal stem cells on the in vitro maturation and subsequent development of mouse oocyte

Mesenchymal stem cells (MSCs) secrete a variety of cytokines and growth factors in addition to self-renewal and multiple forms of differentiation. Some of these secreted bioactive factors could improve meiotic maturation in vitro and subsequent embryo developmental potential. The aim of the present study was to determine whether in vitro maturation (IVM) of mouse oocyte with or without cumulus cells could be improved by contact with conditioned medium (CM) of MSCs as well as the efficiency of CM to support follicular growth and oocyte maturation in the ovarian organ of mice cultured on soft agar. The developmental potential of matured oocyte was assessed by blastocyst formation after in vitro fertilization (IVF). Germinal vesicle stage oocytes with or without cumulus cells were subjected to IVM in either CM, Dulbecco's modified Eagle's medium (DMEM), α-minimum essential medium (α-MEM) or human tubal fluid (HTF). Approximately 120 oocytes were studied for each medium. CM produced a higher maturation rate (91.2%) than DMEM (54.7%), α-MEM (63.5%) and HTF (27.1%). Moreover, CM improved embryo development to blastocyst stage significantly more than DMEM and HTF (85 vs 7% and 41.7%, respectively) but there was no significant difference compared with α-MEM (85 vs 80.3%). The behavior of cortical granules of IVM oocytes cultured in CM revealed cytoplasmic maturation. Moreover, CM also supported preantral follicles growth well in organotypic culture on soft agar resulting in the maturation of 60% of them to developmentally competent oocytes. The production of estrogen progressively increased approximately 1-fold every other day during organ culture, while a dramatic 10-fold increase in progesterone was observed 17 h after human chorionic gonadotropin stimulus at the end of culture. Thus, CM is an effective medium for preantral follicle growth, oocyte maturation, and sequential embryo development.

Recombinant vaccines and the development of new vaccine strategies

Vaccines were initially developed on an empirical basis, relying mostly on attenuation or inactivation of pathogens. Advances in immunology, molecular biology, biochemistry, genomics, and proteomics have added new perspectives to the vaccinology field. The use of recombinant proteins allows the targeting of immune responses focused against few protective antigens. There are a variety of expression systems with different advantages, allowing the production of large quantities of proteins depending on the required characteristics. Live recombinant bacteria or viral vectors effectively stimulate the immune system as in natural infections and have intrinsic adjuvant properties. DNA vaccines, which consist of non-replicating plasmids, can induce strong long-term cellular immune responses. Prime-boost strategies combine different antigen delivery systems to broaden the immune response. In general, all of these strategies have shown advantages and disadvantages, and their use will depend on the knowledge of the mechanisms of infection of the target pathogen and of the immune response required for protection. In this review, we discuss some of the major breakthroughs that have been achieved using recombinant vaccine technologies, as well as new approaches and strategies for vaccine development, including potential shortcomings and risks.

Psychological well-being of the parents and child development, behavior, and quality of life in very low birth weight infants

The parents of premature infants, especially the mothers, are at increased risk for distress. Infants born prematurely are at risk for developmental problems. The aim of this study was to investigate whether the psychological well-being of both parents is associated with child development in very low birth weight (VLBW, ≤1500g) children. The burden of prematurity-related morbidity to the children and to the family was also assessed. A cohort of 201 VLBW infants born during 2001–2006 in the Turku University Hospital, Finland, and their parents were studied (I–IV). One study included a control group (n=166) of full-term infants (IV). The psychological well-being of the parents was evaluated by assessments of depressive symptoms, parenting stress, the sense of coherence and general family functioning. Cognitive, behavioral, and socio-emotional development, and the health-related quality of life (HRQoL) of the children were determined when the children were 2 to 8 years old. The psychological well-being of the parents was associated with the cognitive, behavioral and social development of the VLBW children. The VLBW infants with prematurity-related morbidities had a poorer HRQoL and the general functioning of the family was inferior compared to the control children and their families. 64.5% of the VLBW children survived without morbidities. Most of the VLBW children did not have significant behavior problems (93%), had normal social skills (63%), had no emotional problems (64%), and had no problems in executive functioning (62%). Only 3% of the surviving VLBW infants had significant cognitive delay. In conclusion, the depressive symptoms and stress of the parents can be risk factors for disadvantageous child development, while a strong sense of coherence can be protective. Parents of the premature children with developmental delays might also experience more depressive symptoms and stress than other parents. Prematurity-related morbidities were a burden to the VLBW child as well as to the family.