Relationships between mental toughness, barriers to exercise, and exercise behaviour in undergraduate students

The present study explored relationships between mental toughness (MT), barriers to exercise, and self-reported exercise behaviour in university students. Perceived barriers to exercise are important since previous work has identified barriers as strong predictors of exercise behaviour. MT was hypothesised to predict exercise barriers and self-reported exercise behaviour. Participants were 173 undergraduate students (45 men, 128 women) from 10 United Kingdom universities. Questionnaires were used to assess MT, exercise levels, and exercise barriers. Path analysis identified that MT predicted barriers to exercise, with higher MT associated with weaker perceived barriers. Regular exercisers were found to have significantly higher MT than non-regular exercisers, with commitment identified as a key difference. These findings support the proposed hypotheses and provide further evidence of the importance of MT in exercise / physical activity contexts. Future research that adopts longitudinal designs and tests targeted interventions to reduce perceptions of barriers and enhance exercise participation are encouraged

Non cell autonomous upregulation of CDKN2 transcription linked to progression of chronic hepatitis C disease

Chronic hepatitis C virus infection (C-HC) is associated with higher mortality arising from hepatic and extrahepatic disease. This may be due to accelerated biological aging; however, studies in C-HC have thus far been based solely on telomere length as a biomarker of aging (BoA). In this study, we have evaluated CDKN2 locus transcripts as alternative BoAs in C-HC. Our results suggest that C-HC induces non-cell-autonomous senescence and accelerates biological aging. The CDKN2 locus may provide a link between C-HC and increased susceptibility to age-associated diseases and provides novel biomarkers for assessing its impact on aging processes in man

Advantages and problems of combining GPS with GLONASS

The Global Positioning System (GPS) has been an undoubted success and a great many applications have benefited from it. It does however have limitations, which make its use in certain environments, and for certain tasks, difficult or indeed impossible.In recent years a second satellite based navigation system, the Global'naya Navigatsionnaya Sputnikov Sistema (GLONASS) has become increasingly available. A great deal of interest has been expressed in combining both these systems, in the hope that combined GPS/GLONASS technology will present significant benefits under conditions where GPS alone has struggled. The research described in this thesis was undertaken to examine the potential benefits and problems of such a combination. This has been primarily achieved through the modification of the existing GPS processing software of the Institute of Engineering Surveying and Space Geodesy (IESSG) to accept GLONASS observations. The analysis of data collected under controlled conditions and processed through this software has highlighted biases in the pseudorange measurements from the GLONASS satellites. This is due to the fact that each GLONASS satellite broadcasts on a different frequency, which is then delayed by slightly different amounts through the Radio Frequency (R/F) section of the receiver. If these R/F sections were identical in each receiver, this error source would cancel, but this has not been found to be the case with the receivers used in this research. Interestingly, no such biases have found to be present in the GLONASS carrier phase observations. Various tests have been performed and the data processed through both IESSG and commercially available software. These have highlighted that there are undoubted potential benefits of using combined GPS/GLONASS receivers in environments where visibility is restricted. Under ideal conditions however, the effect of any benefit is reduced, and indeed the biases present in the GLONASS pseudoranges may slightly degrade the accuracy of differential positioning. The software developed has already been used in other research projects within the IESSG. Although the future of the GLONASS system is somewhat uncertain, any future changes to it should be easily accounted for within the code. There is however a real need to further develop and incorporate cycle slip detection software, especially for GLONASS observations, and to investigate the possibility of solving for the biases in the GLONASS pseudoranges

Muscimol inactivation caudal to the interstitial nucleus of Cajal induces hemi-seesaw nystagmus

Hemi-seesaw nystagmus (hemi-SSN) is a jerk-waveform nystagmus with conjugate torsional and disjunctive vertical components. Halmagyi et al. in Brain 117(Pt 4):789–803 (1994), reported hemi-SSN in patients with unilateral lesions in the vicinity of the Interstitial Nucleus of Cajal (INC) and suggested that an imbalance in projections from the vestibular nuclei to the INC was the source of the nystagmus. However, this hypothesis was called into question by Helmchen et al. in Exp Brain Res 119(4):436–452 (1998), who inactivated INC in monkeys with muscimol (a GABAA agonist) and induced failure of vertical gaze-holding (neural integrator) function but not hemi-SSN. We injected 0.1–0.2 ?l of 2% muscimol into the supraoculomotor area, 1–2 mm dorso-lateral to the right oculomotor nucleus and caudal to the right INC. A total of seven injections in two juvenile rhesus monkeys were performed. Hemi-SSN was noted within 5–10 min after injection for six of the injections. Around the time the hemi-SSN began, a small skew deviation also developed. However, there was no limitation of horizontal or vertical eye movements, suggesting that the nearby oculomotor nucleus was not initially compromised. Limitations in eye movement range developed about ½–1 h following the injections. Clinical signs that were observed after the animal was released to his cage included a moderate to marked head tilt toward the left (contralesional) side, consistent with an ocular tilt reaction. We conclude that hemi-SSN can be caused by lesions just caudal to the INC, whereas lesions of the INC itself cause down-beat nystagmus and vertical gaze-holding failure, as demonstrated by Helmchen et al. Combined deficits may be encountered with lesions that involve several midbrain structures

Loss of MeCP2 in Parvalbumin-and Somatostatin-Expressing Neurons in Mice Leads to Distinct Rett Syndrome-like Phenotypes

SummaryInhibitory neurons are critical for proper brain function, and their dysfunction is implicated in several disorders, including autism, schizophrenia, and Rett syndrome. These neurons are heterogeneous, and it is unclear which subtypes contribute to specific neurological phenotypes. We deleted Mecp2, the mouse homolog of the gene that causes Rett syndrome, from the two most populous subtypes, parvalbumin-positive (PV+) and somatostatin-positive (SOM+) neurons. Loss of MeCP2 partially impairs the affected neuron, allowing us to assess the function of each subtype without profound disruption of neuronal circuitry. We found that mice lacking MeCP2 in either PV+ or SOM+ neurons have distinct, non-overlapping neurological features: mice lacking MeCP2 in PV+ neurons developed motor, sensory, memory, and social deficits, whereas those lacking MeCP2 in SOM+ neurons exhibited seizures and stereotypies. Our findings indicate that PV+ and SOM+ neurons contribute complementary aspects of the Rett phenotype and may have modular roles in regulating specific behaviors