Herbivory on woody plants and induced responses in two similar species of Acacia in the Kruger National Park, South Africa

I studied browsing patterns and the effects of browsing by different groups of herbivores on woody plants in Kruger National Park in South Africa. I determined how the browsing pressure varied with distance to water and measured inducible responses on two species of Acacia (A. exuvialis and A. grandicornuta). The experimental approach involved excluding herbivores by the use of fences. Three treatments were used; a full exclosure (FE, excluding all mammals larger than hares), a partial exclosure (PE, excluding elephants and giraffes) and a control area (NE, no exclusion). Two vegetation types were distinguished, related to the crest (further from the river) and the footslope (closer to the river) within the study site. Thirty transects were randomly placed in each treatment (15 on each vegetation type) and the woody plants in each transect were counted and measured. Spines, leaves and shoots were measured on one selected Acacia individual in each transect. In NE and PE browsing severity was estimated on all individuals < 150 cm. Results show that browsing was greater on footslope than on crest, and greater where all herbivores had access to the plants compared to where elephants and giraffes were excluded. Effects of elephant exclusion were greater on crest than on footslope. Some evidence of inducibility of plant responses was found. Spines were 39 % shorter in FE compared to NE for A. exuvialis, but leaf lengths seemed to increase with exclusion of herbivores. A strong positive correlation was found between shoot length and spine abundance, but because of heavy rain near the end of fieldwork, shoot lengths and spine abundances were greatest in PE. The effects of elephants on the woody plants of the savanna ecosystem demonstrated in this study are alarming when considering the rapidly growing populations of elephants and the potential damage they can cause. The greater effect of elephant exclusion I found on the crest is a result which would be interesting to incorporate into elephant management. Long spines and short leaves make plants less attractive to mammalian herbivores and this is very important to consider in the widespread and growing utilization of savanna vegetation as food for livestock, because if the sizes of elephant populations continue to increase, the competition between wildlife and livestock for the savanna ecosystem will do the same

Автоматизированная система обеспечения оптимальных условий выращивания сельскохозяйственных культур в защищенном грунте

Mosquitoes of the Anopheles (An.) and Aedes (Ae.) genus are principal vectors of human diseases including malaria, dengue and yellow fever. Insecticide-based vector control is an established and important way of preventing transmission of such infections. Currently used insecticides can efficiently control mosquito populations, but there are growing concerns about emerging resistance, off-target toxicity and their ability to alter ecosystems. A potential target for the development of insecticides with reduced off-target toxicity is the cholinergic enzyme acetylcholinesterase (AChE). Herein, we report cloning, baculoviral expression and functional characterization of the wild-type AChE genes (ace-1) from An. gambiae and Ae. aegypti, including a naturally occurring insecticide-resistant (G119S) mutant of An. gambiae. Using enzymatic digestion and liquid chromatography-tandem mass spectrometry we found that the secreted proteins were post-translationally modified. The Michaelis-Menten constants and turnover numbers of the mosquito enzymes were lower than those of the orthologous AChEs from Mus musculus and Homo sapiens. We also found that the G119S substitution reduced the turnover rate of substrates and the potency of selected covalent inhibitors. Furthermore, non-covalent inhibitors were less sensitive to the G119S substitution and differentiate the mosquito enzymes from corresponding vertebrate enzymes. Our findings indicate that it may be possible to develop selective non-covalent inhibitors that effectively target both the wild-type and insecticide resistant mutants of mosquito AChE

Förvaltning av signalkräfta i sjöar

Fisket efter signalkräfta har fått allt större ekonomisk och social betydelse i Sverige. Trots detta saknas väl underbyggda råd för hur ett hållbart fiske ska bedrivas.  Projektet ”Utveckling av fisket efter signalkräfta – hur ska man optimera fiske och förutsäga risken för populationskollapser?” är ett projekt som delfinansieras av Europeiska fiskerifonden 2009-2013. Som en inledande del i detta projekt gjordes en litteratursammanställning, och baserat på denna har planeringen av det framtida arbetet kunnat konkretiseras.  Målsättningen med litteraturgenomgången var att identifiera vilken information om signalkräftans biologi och ekologi som behövdes för att kunna ta fram bra fiskerimodeller för hur ett hållbart fiske bör bedrivas. Dessutom var det viktigt att förstå varför vissa bestånd av signalkräfta har kollapsat.  Fångsterna av signalkräfta varierar mellan sjöar. Denna variation kan, i sjöar som inte är försurade, till stor del förklaras med hur stor andel av sjöns botten som är täckt med sten. Finns det mycket sten i en sjö finns det också mycket signalkräftor. Det finns några få studier i Sverige på signalkräftan där populationer har följts under en längre tid (minst 15 år). Dessa visar att fångst per mjärde och uttag av konsumtionskräftor varierar mellan olika år inom en sjö. Dessa variationer kan till viss del förklaras med temperaturen under föregående år, men mekanismen bakom detta är inte känd. Studier av andra arter sötvattenskräftor och en del marina skaldjur (t.ex. hummer) tyder på att rekryteringen (reproduktionsframgången) till viss del kan förklara variationerna i fångstnivåer mellan olika år.  Denna litteraturgenomgång visar att det saknas väsentlig information om signalkräftans ekologi och biologi för att kunna ta fram teoretiska modeller som ska ligga till grund för rekommendationer om hur ett hållbart fiske ska bedrivas. De beståndsanalyser som bedömts vara intressanta för signalkräfta kräver vissa dataunderlag för att ge tillförlitliga resultat. De enskilt viktigaste faktorerna är rekryteringsframgång, tillväxt, naturlig dödlighet, och detaljerad fiskeristatistik (ansträngning, selektivitet, fångster etc.). Med anledning av resultaten från denna litteraturgenomgång bedömdes följande insatser som prioriterade:  • undersöka betydelsen av honans storlek för rekryteringsframgång • utveckla tekniken för märkning av kräftor i olika typer av bestånd för att sedan kunna använda återfångstdata för att bestämma individuell tillväxt, naturlig dödlighet och fiskeridödlighet  • uppskatta ytan tillgängligt kräfthabitat för olika kräftbestånd och bedöma i vilken mån det påverkar potentiellt fiskeuttag  • analysera ett flertal sjöar med och utan populationskollapser och undersöka vilka miljöfaktorer som kan förklara uppkomsten av kollapser  • analysera såväl pestfrekvens som infektionsgrad i enskilda kräftor och utvärdera om det finns en koppling mellan populationskollapser och ökade pestangrepp i sjöa

Air - for Health and Comfort, An Analysis of HVAC Systems' Performance in Theory and Practice

One part of the objective is to analyze how different ventilation systems perform in practice when it comes to supplying and exhausting designed air flow in different outdoor and indoor conditions. The other part is to analyze the design criterias and the energy use of a variable air volume system based on controlled static pressure at the branch duct level and supplying outdoor air only. To investigate the technical status of ventilation systems, the result from the compulsory testing and examination of ventilation systems (OVK) is used. A multi-zone model (COMIS) is used to study the air flow in a multi-family building. Two ventilation systems are analyzed with the same building; the mechanical exhaust and the mechanical supply and exhaust system. Fundamental pressure loss equations, measurements and a computer program are used to determine how much the air flow at the air terminals on a branch with controlled static pressure differs. A model is developed to determine the optimal supply air temperature with respect to energy use. An average of 34% of the studied ventilation systems performed as intended. Both the mechanical exhaust and the mechanical supply and exhaust air system showed sensitiveness to outdoor temperature, building airtightness and wind. When the static pressure is controlled to be constant at the branch duct level it is possible to vary the air flow to different zones without measuring the individual flow and without significantly influence the air flow to other zones. When using 100% outdoor air the indoor air quality will be improved during most of the year. There is a great potential in controlling the supply air temperature optimally to reduce the energy use

Skattning av biverkningar : Sjuksköterske- och patientuppfattning om behandlingsrelaterade biverkningar vid stamcellstransplantation.

A possible treatment for patients with lymphoma and myeloma is stem cell transplantation (SCT). SCT is preceded with cytostatic treatment. There are several side effects related to this treatment, for example fatigue, nausea, constipation/diarrhoea, pain, mucositis and loss of appetite. Aim: Investigate which side effects related to the treatment where most troubling after SCT and if nurse assessment and patient assessment differ. Methods: A quantitative empirical study with repeated measuring. The two groups of nurses and patients answered a form independently. Results: Loss of appetite and fatigue are the most troubling side effects according to both nurse and patient. Older patients tended to be more affected by fatigue. The nurses estimated the side effects such as loss of appetite, fatigue, diarrhoea and nausea lower than the patients did. Conclusion: No definitive conclusion could be made because of the small patient/nurse sample. However, there is a tendency showing difficulty for nurses to estimate correctly the side effects suffered by the patients. The nurses tend to estimate the side effects lower than the patients do

Optimal supply air temperature with respect to energy use in a variable air volume system

In a variable air volume (VAV) system with 100% outdoor air, the cooling need in the building is satisfied with a certain air flow at a certain supply air temperature. To minimize the system energy use, an optimal supply air temperature can be set dependent on the load, specific fan power (SFP), chiller coefficient of performance, outdoor temperature and the outdoor relative humidity. The theory for an optimal supply air temperature is presented and the heating, ventilation and air-conditioning (HVAC) energy use is calculated depending on supply air temperature control strategy, average U-value of the building envelope and two outdoor climates. The analyses show that controlling the supply air temperature optimally results in a significantly lower HVAC energy use than with a constant supply air temperature. The optimal average U-value of the building envelope is in practise mostly zero. (C) 2003 Elsevier B.V. All rights reserved

Pressure controlled variable air volume system

There is one primary goal and several secondary goals to fulfill when designing a heating, ventilation and air conditioning (HVAC) system. The main goal is to create an indoor climate that satisfies the user and this should be achieved in the most energy efficient way and with a system that also function in a long-term perspective. Higher supply air flow have the potential of increasing office workers performance and decreasing short-term sick leave. To increase the supply air flow, a cooling function is added to the air and 100% outdoor air is supplied. The main objective of this paper is to give the fundamentals for a system design that takes good indoor climate, energy efficiency and long-term operation into account. When controlling the static pressure at branch level, it is possible to vary the air flow to different zones without measuring the individual flow and without affecting the air flow to other zones. An equation for the placement of the pressure sensor is shown and the relative flow difference between the diffusers on the branch is calculated and measured. These principals are the fundamentals for a pressure controlled variable air volume (VAV) system. The fan pressure set point is optimized resulting in a decreased fan power requirement and sound generation. The flow to each zone is controlled at the diffuser outlet which prevents draft and therefore a wide range in supply air temperature can be used. (C) 2003 Elsevier B.V. All rights reserved