Deficiency and abelianized deficiency of some virtually free groups

Let $Q_m$ be the HNN extension of $\Z/m \times \Z/m$ where the stable letter conjugates the first factor to the second. We explore small presentations of the groups $\Gamma_{m,n}=Q_m \ast Q_n$. We show that for certain choices of (m,n), for example (2,3), the group $\Gamma_{m,n}$ has a relation gap unless it admits a presentation with at most 3 defining relations, and we establish restrictions on the possible form of such a presentation. We then associate to each (m,n) a 3-complex with 16 cells. This 3-complex is a counterexample to the D(2) conjecture if $\Gamma_{m,n}$ has a relation gap.Comment: 7 pages; no figures. Minor changes; now to appear in Math. Proc. Camb. Phil. So

The effects of hydration status on markers of oxidative and cellular stress during prolonged exercise in hyperthermic environments

The relationships between hyperthermia, dehydration and oxidative stress have been thoroughly studied  separately within the literature both in vitro and in vivo. However, no in vivo attempts have been made to  manipulate the hydration status of individuals to investigate the resulting changes in oxidative and cellular stress during and after exercise in hyperthermic conditions and what effect these changes may have on  exercise performance.The purpose of the first experiment was to investigate the effects of exercise-induced dehydration with and without hyperthermia on oxidative stress. Seven healthy male trained cyclists (mean ± SD) age: 36 ± 6 yrs, height: 177.4 ± 6.5 cm, weight: 72.8 ± 7.0 kg, and power output (PO) at lactate threshold (LT): 199.3 ± 19.0 Watts (W) completed 90 min cycling exercise at 95% LT followed by a 5 km time trial (TT) in four conditions: 1) euhydration in a warm environment (EU-W, control), 2) dehydration in a warm environment (DE-W), 3) euhydration in a thermoneutral environment (EU-T), and 4) dehydration in a thermoneutral environment (DE-T) (W: 33.9 ± 0.9°C; T: 23.0 ± 1.0°C). Whole blood oxidised glutathione (GSSG) increased significantly post exercise in dehydration trials only (DE-W: p < 0.01, DE-T: p = 0.03), and while not significant, whole blood total glutathione (TGSH) and plasma thiobarbituric acid reactive substances (TBARS) tended to increase post exercise in dehydration trials (p = 0.08 for both). Intracellular monocyte heat shock protein 72 (HSP72) concentration was increased (p = 0.01) while intracellular lymphocyte HSP32 concentration was decreased for all trials (p = 0.02). Exercise-induced dehydration led to an increase in GSSG concentration while maintenance of euhydration attenuated these increases regardless of environmental condition. Additionally, evidence of increased cellular stress (measured via HSP) was found during all trials independent of body mass loss and environment. Finally, total distance covered during 90 min and PO during both 90 min and 5 km TT performance were reduced during only the DE-W trial, likely a result of combined cellular stress, hyperthermia and dehydration. These findings highlight the importance of fluid consumption during exercise to attenuate thermal and oxidative stress during prolonged exercise in the heat.The purpose of the second experiment was to investigate the effect of prolonged exercise-induced dehydration with and without hyperthermia on cellular and oxidative stress markers in untrained individuals, to serve as a comparison to the results of the first experimental chapter. Seven untrained male university students (mean ± SD) age: 21 ± 3 yrs, height: 181.1 ± 9.2 cm, weight: 76.8 ± 8.8 kg, and PO at LT 100.0 ± 13.0 W, who were unacclimatised to heat, participated in this study. Subjects completed the same experimental protocol as outlined in experimental chapter one, in warm (33.9 ± 1.0°C) and thermoneutral (22.9 ± 1.0°C) environments. Whole blood GSSG increased an average of 32% (p < 0.01) as a result of prolonged exercise, however unlike the trained subjects of experiment one, there was no effect of body mass loss on GSSG (p = 0.63). Similarly, intracellular monocyte HSP72 concentration increased 14% (p < 0.01) as a result of prolonged cycling regardless of body mass loss and environmental heat stress, analogous to subjects in experiment one. While there were no significant changes as a result of hydration or environment, a relationship was found between GSSG concentration and body mass loss (r2 = 0.5, p = 0.05), while HSP72 was correlated with body temperature and levels of heat storage (r2 = 0.5, p = 0.01). Similar to the trained individuals in experiment one, PO during the 90 min (7%, p < 0.01) and TT (14%, p < 0.01) were decreased while thermoregulation was impaired during DE-W only. These results demonstrate the increased level of stress in untrained subjects as a result of exercise and highlight the importance of participation in recommended physical activity to aid in positive cellular adaptations leading to superior antioxidant defences to aid in disease prevention.In light of the findings from the first experimental chapter that dehydration can significantly influence oxidative stress in trained subjects, the purpose of the third experimental chapter was to compare pre-exercise hyperhydration with plain water (W) or water with glycerol (G) to no hyperhydration (C) on markers of oxidative stress prior to and after a 90 min TT. Seven trained male cyclists and triathletes (age: 28 ± 8 yrs, height: 178.4 ± 7.8 cm, and mass: 73.2 ± 9.6 kg) covered as much distance as possible during a 90 min cycle after G, W or C. Blood was collected pre ingestion (PRE), post ingestion/pre exercise (PI), immediately post exercise (PE) and 1 hour post exercise (1HR) and analysed for whole blood TGSH, GSSG, and plasma levels of lipid hydroperoxides (LOOH) and protein carbonyls (PC). TGSH concentration increased post exercise in W and C (p < 0.01) while PC concentration increased post exercise during C only (p = 0.03). Additionally, GSSG concentration was greater PI and PE in C compared to G (p = 0.05, and p < 0.01, respectively), likely due to the inferior amount of fluid retained during C compared to the G and W trials. Therefore, it appears that both pre exercise hyperhydration with ad libitum fluid ingestion during exercise is sufficient to attenuate rises in exercise-induced oxidative stress.The novel findings presented in this thesis indicate fluid ingestion plays a vital role in providing cellular protection from oxidative stress. These results suggest that individuals participating in prolonged exercise should consume adequate fluid during exercise to avoid dehydration, matching fluid intake with body mass loss. Additionally, individuals who wish to hyperhydrate prior to exercise may enhance their ability to delay dehydration and thus enhance their cellular protection from oxidative stress

An Innovative Cold-formed Floor System

Optimizing the use of building materials has always been one of the primary goals of engineers. It is a constant challenge to seek innovative methods to build lighter weight structures. Sometimes this is achieved through the development of new building materials, other times it can be accomplished by creating entirely new types of structural systems. Often lightweight structures can be more asthetically pleasing because of their stream-lined appearance. However, in general the motivating factor in building lightweight structures is to reduce the overall cost. One portion of a structure which offers tremendous potential for weight reduction is the floor system. The floor system is one of the heaviest components in typical steel framed buildings. A reduction in the dead load of this component will result in a subsequent reduction in the total weight of the building structural system

Anaerobic Nitrogen Fixation in Some Iowa Soils

Data secured by various investigators have proven quite conclusively that the aerobic nitrogen-fixing bacteria of the genus Azotobacter are not active or even present in soils more acid than pH 6.0. Many of the soils in Iowa are more strongly acid than this, and while no Azotobacter have been found in them, some nitrogen fixation certainly occurs. It appears, therefore, that some other organisms or groups of organisms must be responsible

ICTV Virus Taxonomy Profile: Chrysoviridae

The Chrysoviridae is a family of small, isometric, non-enveloped viruses (40 nm in diameter) with segmented dsRNA genomes (typically four segments). The genome segments are individually encapsidated and together comprise 11.5–12.8 kbp. The single genus Chrysovirus includes nine species. Chrysoviruses lack an extracellular phase to their life cycle; they are transmitted via intracellular routes within an individual during hyphal growth, in asexual or sexual spores, or between individuals via hyphal anastomosis. There are no known natural vectors for chrysoviruses. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the Chrysoviridae, which is available at www.ictv.global/report/chrysoviridae.Peer reviewe

Eimeria spp. infecting quenda (Isoodon obesulus) in the greater Perth region, Western Australia

Parasites of wildlife inhabiting urbanised and peri-urban environments are of interest regarding wildlife population health, and also veterinary public health in the case of parasites that can also infect humans and domestic animals. This study aimed to: identify, and estimate the prevalence of, species of Eimeria parasitic in quenda (Isoodon obesulus) in the greater Perth region, Western Australia; 2) morphologically describe and genetically characterise a novel observed species of Eimeria as E. angustus; and 3) genetically characterise E. kanyana. Eimeria spp. prevalence was 76.1% (95% CI 64.9–84.5%), and four putative species of Eimeria were identified. Eimeria kanyana was identified infecting quenda for the first time, with a prevalence of 54.9% (43.4–66.0%). Eimeria quenda was less prevalent, at 7.0% (3.1–15.5%). The novel species E. angustus was present in 45.1% of sampled quenda (34.0–56.6%). A second novel morphotype of Eimeria was present in 2.8% of sampled quenda (0.9–9.7%). Mixed Eimeria spp. infections were present in 21/71 quenda (29.6%, 95% CI 20.2–41.1%). Molecular phylogenetic analyses of E. kanyana and E. angustus were conducted at the 18S rRNA and mitochondrial cytochrome oxidase loci. At both loci, two isolates identified as E. kanyana grouped in a phylogenetic clade with E. trichosuri. Five isolates identified as the novel E. angustus were most closely related to E. tropidura at the 18S locus. At the COI locus, no sequence data were available for E. tropidura; isolates of E. angustus grouped with E. sciurorum

ICTV Virus Taxonomy Profile: Chrysoviridae

Members of the family Chrysoviridae are isometric, non-enveloped viruses with segmented, linear, dsRNA genomes. There are 3–7 genomic segments, each of which is individually encapsidated. Chrysoviruses infect fungi, plants and possibly insects, and may cause hypovirulence in their fungal hosts. Chrysoviruses have no known vectors and lack an extracellular phase to their replication cycle; they are transmitted via intracellular routes within an individual during hyphal growth, in asexual or sexual spores, or between individuals via hyphal anastomosis. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the family Chrysoviridae, which is available at ictv.global/report/chrysoviridae.Peer reviewe

A facility for high resolution spectroscopy: Laboratory and ground based observations in support of upper atmospheric research

This research task consists of operating a facility for making spectroscopic observations in support of upper atmospheric research. The facility responds to the needs and interests of the visiting investigators. Therefore, the research objectives are not predetermined except in broad outline. The emphasis is on studies that take advantage of the particular strengths of the Fourier Transform Spectrometer on Kitt Peak: high spectral resolution combined with wide spectral range and low noise