Effects of intensity of forest regeneration measures on some ecosystem services in a nationwide Swedish field experiment

Effects on important ecosystem services (total and species-wise biomass production, distributed on tree fractions), of three regimes with different intensities of forest regeneration measures after clear-cutting were evaluated 24-27 years after initiation of a field experiment at 14 sites across Sweden. The three treatments, designated high (HI), normal (NI) and low (LI) respectively consisted of: mechanical site preparation and planting of large seedlings at 2 x 2 m spacing, with supplemental planting and pre-commercial thinning (PCT) when deemed necessary; standard local practices; and natural regeneration with no site preparation, artificial regeneration or PCT. Over all, significantly more total biomass was found in the HI (53.6 ton ha-1) and NI (40.8 ton ha-1) treatments compared to the LI (23.5 ton ha-1) treatment. For stem biomass, significant differences were found only between the HI and LI (37.0 and 16.5 ton ha-1, respectively) treatments, and the same result was also found for living branches; HI (8.2 ton ha-1) and LI (5.3 ton ha-1). For foliage, the two managed treatments had significantly higher values, 7.5 ton ha-1 (HI) and 6.3 ton ha-1 (NI) compared to 3.0 ton ha-1 for the LI treatment. Also for dead branches the highest value was found in the HI treatment (3.3 ton ha-1), significantly higher compared to the LI treatment (0.7 ton ha-1). In addition to effects on biomass production and allocation, the regeneration intensity also influenced stand structure and composition. Hence, regeneration intensity may affect biodiversity, ecosystem functions and social values in a number of different ways

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Escherichia coli Fimbriae, Bacterial Persistence and Host Response Induction in the Human Urinary Tract

Urinary tract infections (UTI) are among the most common bacterial infections in humans. Symptomatic UTIs may be acute, recurrent or chronic but the most frequent form of UTI is asymptomatic bacteruria (ABU). In ABU, the mucosa remains inert, despite the presence of large bacterial numbers in urine. The difference in disease severity reflects the virulence of the infecting strain and the propensity of the host to respond to infection. It is essential to understand the molecular basis of disease diversity and the molecular interactions between bacteria and host that determine asymptomatic carriage and the transition to disease. This thesis concerns the initial interactions between bacteria with the mucosal surfaces in the human urinary tract, and the bacterial factors involved in the breach of mucosal inertia. Specifically, the contribution of P and type 1 fimbriae to bacterial establishment and host response induction are investigated. The human bacteriuria model was used, since ABU protects against infections with more virulent strains. To study the role of adherence in UTI an Escherichia coli ABU strain, which does not express adherence factors, was transformed with DNA sequences encoding P or type 1 fimbriae and used for deliberate inoculation of patients with a history of recurrent UTI. P fimbriae were shown to provide a colonization advantage during the first days of bacterial establishment, as compared to the ABU strain lacking P fimbriae. In addition, P fimbriated E. coli were shown to trigger the innate mucosal responses, with increases in urine IL-6 and IL-8 concentrations, and recruitment of neutrophils. This effect was adhesion dependent, as shown by inoculations with a P fimbriated mutant lacking the PapG, adhesin. The P fimbriated bacteria adhered to uroepithelial cells in vivo, but adherence was not observed with the papG deletion mutant. After similar inoculations, type 1 fimbriae were not found to help the establishment of bacteriuria or the mucosal host response in the human urinary tract. This is surprising as type 1 fimbriae have been identified as important virulence factors in animal models of UTI. The results show that P fimbriae serve as independent virulence factors when expressed by an ABU strain, by promoting the establishment of bacteriuria and the innate host response, which is the cause of symptoms and tissue damage. P fimbriae thus fulfil the molecular Koch postulates as independent virulence factors in the human urinary tract. Type 1 fimbriae, in contrast, did not act as virulence factors in this model, and thus appear to serve a different function in man

Der Einfluss von P-Fimbrien auf eine Leukozyturie und den Schwellenwert einer persistierenden Bakteriurie [Effect of P fimbriae on pyuria and bacterial colonization of the human urinary tract]

This study investigated the role of P fimbriae in colonization of Escherichia coli, host response, and bacterial persistence in humans. Human volunteers were inoculated intravesically with the nonadherent ABU isolate E. coli 83972 and with P fimbriated transformants of the same strain. During the following 24 h all urine samples, and thereafter daily samples, were collected for urine culture, analysis of neutrophil numbers, and cytokine concentrations (IL-6 and IL-8). The P fimbriated transformants showed enhanced bacterial colonization in comparison to E. coli 83972 and lowered the bacterial numbers needed for persistent bacteriuria. The P fimbriated transformants also lowered the bacterial numbers needed for a significant neutrophil and cytokine host response. We conclude that P fimbriae enhance bacterial colonization and trigger the host response in the human urinary tract

Reproductive performance in high-producing dairy cows

Milk yields >10,000 kg/year are common in modern dairy production, owing to improved nutrition, management and genetic gains through use of progeny-tested bulls. However, reproductive performance has decreased worldwide in many cows with a high genetic potential for milk production, particularly in the Holstein breed. Moreover, cow robustness and longevity is also threatened by increasing stress, udder health disturbances and of locomotion disorders. Genetic global misuse of a narrow base of AI sires -including those selected for high milk yield but not consequently for health and reproductive traits- has not only contributed to these undesirable effects on animal health and welfare but, together with sub-optimal management, jeopardized the ethical and economical sustainability of modern dairy farming. This review describes the state-of-the-art of this multifaceted problem and advises on how to ameliorate it, since it is not seen as an unsolvable problem. Use of high-fertility sires, of balanced breeding programs with adequate trait measurements, diet optimization, design of buildings and management systems that best support reproduction as well as cross-breeding; are among short- and medium-term strategies. In a longer perspective, holistic- and trait-orientated research on interrelations between gene regulation of nutrition, lactation and stress is needed; aiming at identifying reliable and cheap markers to be used on-line and on-farm as recorders of genetic traits. Awaiting the full application of juvenile genomic selection, a wider inclusion of functional traits (fertility, health and longevity) and of product quality are mandatory for breeding programs in order to secure acceptable fertility, sustained milk production and the best welfare of dairy cows. Such strategies have proven successful in the Nordic countries and are being increasingly adopted by others

PapG-dependent adherence breaks mucosal inertia and triggers the innate host response

Mucosal pathogens differ from normal flora constituents in that they provoke a host response that upsets mucosal integrity. We investigated whether the elaboration of discrete adherence factors is sufficient to break the inertia of the mucosal barrier. PapG-mediated adherence was selected as an example, because P fimbrial expression characterizes uropathogenic Escherichia coli and because adherence starts the attack on the mucosal barrier. Patients were inoculated intravesically with transformed nonvirulent E. coli strains expressing functional P fimbriae (E. coli pap(+)) or mutant fimbriae lacking the adhesin (E. coli DeltapapG). E. coli pap(+) was shown to activate the innate host response, and adherent gfp(+) bacteria were observed on excreted uroepithelial cells. E. coli DeltapapG failed to trigger a response and was nonadhesive. We conclude that PapG-mediated adherence breaks mucosal inertia in the human urinary tract by triggering innate immunity and propose that this activation step differentiates asymptomatic carriage from infection