Evolution of drug-tolerant nematode populations in response to density reduction

Resistance to xenobiotics remains a pressing issue in parasite treatment and global agriculture. Multiple factors may affect the evolution of resistance, including interactions between life-history traits and the strength of selection imposed by different drug doses. We experimentally created replicate selection lines of free-living Caenorhabditis remanei exposed to Ivermectin at high and low doses to assess whether survivorship of lines selected in drug-treated environments increased, and if this varied with dose. Additionally, we maintained lines where mortality was imposed randomly to control for differences in density between drug treatments and to distinguish between the evolutionary consequences of drug-treatment versus ecological processes due to changes in density-dependent feedback. After 10 generations, we exposed all of the selected lines to high-dose, low-dose and drug-free environments to evaluate evolutionary changes in survivorship as well as any costs to adaptation. Both adult and juvenile survival were measured to explore relationships between life-history stage, selection regime and survival. Intriguingly, both drug-selected and random-mortality lines showed an increase in survivorship when challenged with Ivermectin; the magnitude of this increase varied with the intensity of selection and life-history stage. Our results suggest that interactions between density-dependent processes and life history may mediate evolved changes in susceptibility to control measures

Accountability: Papers from master theses 2009

Last year, we presented the book “Accountability 2008: papers from master theses”. The book contained eleven papers. Each paper was based on a thesis in the field of Accounting, Auditing and Control, on which these students received a Master’s degree in Economics & Business from the Erasmus School of Economics in 2008. We intended this book to be the beginning of an annual book series. The fact that you are now reading the preface of a second volume shows that this intention seems to become reality. In fact, we are confident that these two volumes are really the beginning of a series of books with papers of master theses in accounting. We have at least three reasons to be this confident. First, we believe that the two purposes of starting this book series will remain as important in the future as they are now. These two purposes are first, to provide a wider audience for theses that deserve that, and second, to offer some help to current and future master students in the streams of Accounting & Finance or Accounting, Auditing, and Control in writing their theses by presenting “good practices” from earlier theses. Second, as last year, the students who were invited to submit a paper for this year’s edition, without any exception, were all very enthusiastic to contribute to this book. Even though they had already finished their master theses and received their master’s degree, they were still willing to put in additional effort to turn their thesis into a paper that should not exceed 7.000 words. The fact that (almost) all contributors succeeded to not only do that but also before the deadline, shows that this book is seen as a good opportunity for students to disseminate the results of their master theses to a wider audience. Third, despite the economic crisis, we found some sponsors for this book, which is promising for the future

Stochastic Model for the Motion of a Particle on an Inclined Rough Plane and the Onset of Viscous Friction

Experiments on the motion of a particle on an inclined rough plane have yielded some surprising results. For example, it was found that the frictional force acting on the ball is viscous, {\it i.e.} proportional to the velocity rather than the expected square of the velocity. It was also found that, for a given inclination of the plane, the velocity of the ball scales as a power of its radius. We present here a one dimensional stochastic model based on the microscopic equations of motion of the ball, which exhibits the same behaviour as the experiments. This model yields a mechanism for the origins of the viscous friction force and the scaling of the velocity with the radius. It also reproduces other aspects of the phase diagram of the motion which we will discuss.Comment: 19 pages, latex, 11 postscript figures in separate uuencoded fil

Indirect learning: how emerging-market firms grow in developed markets

Some emerging-market firms have recently achieved substantial growth in developed markets despite having had little prior experience in these markets. What explains the performance of these firms? Building on the organizational learning literature, the authors argue that indirect learning (i.e., learning from the experience of others) plays a crucial role in explaining this phenomenon. Specifically, they propose that emerging-market firms that grow in developed markets overcome their lack of direct experience in such markets by learning indirectly through their leaders, competitors, and interfirm networks. The authors test their thesis by comparing the international growth in developed markets of a sample of emerging-market firms (116 Indian firms) with a sample of developed-market firms (160 U.K. firms). The results support the authors' thesis about the importance of indirect learning in explaining the international growth of emerging-market (relative to developed-market) firms in developed markets. The authors discuss the implications of these findings for policy makers in the areas of higher education, competition policy, and international trade as well as for managers in the areas of middle-management recruitment, competitor analysis and tracking, and managing interfirm networks

Clinical evaluation of anaemia in sheep: early trials

Trials were conducted on a farm in Mpumalanga Province in South Africa to test the possibility of grading the colour of the ocular mucous membranes of sheep as an indication of the extent to which the animals are affected by Haemonchus contortus infection. The range of observed colour shades were classified into five categories, from red, through red-pink, pink and pink-white to white. Over a period of 125 days routine drenching of a flock of 388 sheep on irrigated kikuyu ( Pennisetum clandestinum) pasture was terminated. During this time the animals were examined at practically weekly intervals and haematocrit determinations done for all the sheep with pale conjunctivae. Only those sheep having a haematocrit of 15% or lower were treated. Compared to a previous drenching tempo of close to every 3 weeks during the Haemonchus season on the farm, drenching was reduced by approximately 90%, as 70% of the sheep did not require salvage drenching and only 10% of the flock had to be given more than one salvage treatment. At the time of the trial the five clinical classifications were not related to predetermined haematocrit categories. However, when compared to categories that were set in later trials, 94% of the clinical estimates in the present trial were either in the correct haematocrit category, or, if not, the sheep were probably not disadvantaged by the errors. In 2.6% of cases the incorrect estimate may have placed the sheep concerned in jeopardy, as the haematocrit values were so low that salvage drenching was required, while the sheep were not regarded as anaemic. Changes in the mean haematocrit values of drenched and undrenched sheep were mirrored reciprocally by the changes in clinical colour estimates. Lactating ewes were by far the most susceptible class of sheep, as only 44.6% of them were able to manage without drenching, compared to 83% of dry, and 70.6% of pregnant ewes. Correlations between the haematocrits and clinical estimates were highly significant, although the associations were not high enough to give reasonable surety that the haematocrit values of individual animals could be predicted with confidence from their clinical classifications. Exceptionally large numbers of worms were recovered from seven of the 14 sheep that were culled because of age at the end of the trial, but these were reflected neither in their faecal worm egg counts, nor, with one exception only, in clinical signs.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

Temporal changes in inhibin subunit mRNAs during atresia of preovulatory follicles in the rat

This study aimed to investigate the time course of disappearance of the mRNAs of the various subunits of inhibin in follicles which become atretic. An animal model was used in which atresia of preovulatory follicles could be studied in a chronological order. Injection of gonadotrophin-releasing hormone (GnRH) antagonist (20 microg) at the morning of pro-oestrus (P) blocked ovulation and the 10-12 preovulatory follicles became gradually atretic. A second injection was given the next day to prevent delayed ovulation. The rate of atresia could be delayed by simultaneous administration of a subovulatory dose of human chorionic gonadotrophin (hCG) (0.5 IU) and could be advanced by administration of a fivefold larger amount of GnRH antagonist. Functional activity of follicles becoming atretic was studied by measuring oestradiol production after incubation of individual follicles for 4 h. Follicles isolated 24 h after the first injection of GnRH antagonist (P+24) already secreted significantly less oestradiol in vitro than follicles isolated at pro-oestrus, although they were morphologically not different from pro-oestrous follicles. Follicles isolated at P+24 from hCG-treated rats secreted more oestradiol compared with follicles from rats not treated with hCG. In contrast, follicles isolated at P+24 from rats that were given a fivefold larger amount of GnRH antagonist secreted less oestradiol. Once this model was validated, temporal changes in inhibin subunit mRNAs in follicles undergoing atresia were measured by in situ hybridization and RNase protection assay. In situ hybridization showed abundant alpha- and betaA-subunit mRNA in the whole granulosa layer of preovulatory follicles at P and P+24, while betaB-subunit mRNA was restricted to the antral layer and cumulus. At P+48 the amount of alpha- and betaA-subunit mRNA had declined and was restricted to the cumulus, whereas betaB-subunit mRNA was absent. In the atretic follicles present at P+72 and P+96, mRNAs of all three inhibin subunits were absent. Administration of 0.5 IU hCG delayed the decline in the amount of alpha, betaA and betaB mRNA in preovulatory follicles at P+48. RNase protection assay of inhibin subunits in isolated follicles revealed no changes between P and P+24. However, at P+48, the mRNAs of alpha- an

Cancer centre information and support services and patient needs:participatory action research study

Objectives:Clear information and supportive care are necessary for oncology patients and their relatives to manage the disease (trajectory). Centres for information and support aim to address their needs by offering informal and non-medical formal services. This study evaluated whether the centres’ services offered meet the needs of its visitors, and whether there is interest for these among oncology patients treated at affiliated hospitals.Methods:In this participatory action research, interviews were conducted among visitors of two centres (Patient Information Center Oncology (PATIO) and IntermeZZo) and among patients treated at the affiliated hospitals. Visitors were interviewed to share their experiences regarding the centres’ services offered. Patients from the hospitals were interviewed about their interest in such support. Data were collected during three different periods and adjustments were made to the centres’ services between measurements. Results:111 (PATIO) and 123 visitors (IntermeZZo) were interviewed, and 189 and 149 patients at the respective hospitals. Reasons to visit PATIO/IntermeZZo were to relax (93.1%), seek professional advice (54.6%) and meet peers (36.3%). Visitors indicated that the visits met their needs (99.1%), citing the accessible support and the expertise in oncology. 20% of patients interviewed at the hospitals expressed interest in visiting PATIO/ IntermeZZo. The majority of patients (89.6%) considered these centres an integral part of their treatment process. These findings were stable over time. Conclusions:Patients and their relatives highly value the services of hospital-affiliated centres for information and support. Future research should address how such centres best be integrated in the Dutch healthcare system.</p

Cancer centre information and support services and patient needs:participatory action research study

Objectives:Clear information and supportive care are necessary for oncology patients and their relatives to manage the disease (trajectory). Centres for information and support aim to address their needs by offering informal and non-medical formal services. This study evaluated whether the centres’ services offered meet the needs of its visitors, and whether there is interest for these among oncology patients treated at affiliated hospitals.Methods:In this participatory action research, interviews were conducted among visitors of two centres (Patient Information Center Oncology (PATIO) and IntermeZZo) and among patients treated at the affiliated hospitals. Visitors were interviewed to share their experiences regarding the centres’ services offered. Patients from the hospitals were interviewed about their interest in such support. Data were collected during three different periods and adjustments were made to the centres’ services between measurements. Results:111 (PATIO) and 123 visitors (IntermeZZo) were interviewed, and 189 and 149 patients at the respective hospitals. Reasons to visit PATIO/IntermeZZo were to relax (93.1%), seek professional advice (54.6%) and meet peers (36.3%). Visitors indicated that the visits met their needs (99.1%), citing the accessible support and the expertise in oncology. 20% of patients interviewed at the hospitals expressed interest in visiting PATIO/ IntermeZZo. The majority of patients (89.6%) considered these centres an integral part of their treatment process. These findings were stable over time. Conclusions:Patients and their relatives highly value the services of hospital-affiliated centres for information and support. Future research should address how such centres best be integrated in the Dutch healthcare system.</p

Somatostatin receptor scintigraphy: Its value in tumor localization in patients with Cushing's syndrome caused by ectopic corticotropin or corticotropin-releasing hormone secretion

purpose: To assess the feasibility of somatostatin receptor scintigraphy for patients with Cushing's syndrome caused by tumors secreting ectopic corticotropin or corticotropin-releasing hormone (CRH). patients and methods: Ten patients with Cushing's syndrome, nine with ectopic corticotropin-secreting tumors and one with a CRH-secreting tumor, were consecutively studied. For comparison purposes, eight patients with corticotropin-secreting pituitary tumors and one patient with an autonomous adrenal adenoma were investigated. In vivo tumor localization was performed for all patients using a radionuclide-coupled somatostatin analog. The results obtained with this technique were compared with those obtained with conventional imaging techniques. For some patients, the clinical effects of octreotide therapy were evaluated. results: Somatostatin analog scintigraphy successfully identified the primary ectopic corticotropin-secreting and CRH-secreting tumors or their metastases, or both, in 8 of 10 patients; in 2 patients with corticotropin-secreting bronchial carcinoids, the tumors could not be visualized. Normal scans were obtained for the 8 patients with corticotropin-secreting pituitary tumors and the one patient with an adrenal adenoma. conclusion: Somatostatin analog scintigraphy can be included as a diagnostic step in the workup of Cushing's syndrome patients with a suspected ectopic corticotropin-secreting tumor or a CRH-secreting tumor

A nurse-led sexual rehabilitation intervention after radiotherapy for gynecological cancer

Purpose: Although vaginal dilator use after combined pelvic radiation therapy and brachytherapy (RT/BT) is recommended to prevent vaginal shortening and stenosis, women fail to use them and experience sexual problems. A nurse-led sexual rehabilitation intervention targeting sexual recovery and vaginal dilatation was developed. Its feasibility was investigated during a prospective, longitudinal, observational pilot study. Methods: Four oncology nurses were specifically trained to conduct the intervention. Gynecologic cancer patients treated with RT/BT were assessed using (i) questionnaires on frequency of dilator use (monthly), sexual functioning, and sexual distress (at baseline and 1, 6, and 12 months) and psychological and relational distress (at 1, 6, and 12 months); (ii) semi-structured interviews (between 6 and 12 months); and (iii) consultation recordings (a random selection of 21 % of all consults). Results: Twenty participants were 26–71 years old (mean = 40). Eight participants discontinued participation after 3 to 9 months. At 6 months after RT, 14 out of 16 (88 %), and at 12 months 9 out of 12 (75 %), participants dilated regularly, either by having sexual intercourse or by using dilators. Sexual functioning improved between 1 and 6 months after RT, with further improvement at 12 months. Most participants reported that the intervention was helpful and the nurses reported having sufficient expertise and counseling skills. Conclusions: According to the pilot results, the intervention was feasible and promising for sexual rehabilitation and regular dilator use after RT. Its (cost-)effectiveness will be investigated in a randomized controlled trial