DETECTABILITY AND ERROR ESTIMATION IN ORBITAL FITS OF RESONANT EXTRASOLAR PLANETS

We estimate the conditions for detectability of two planets in a 2/1 mean-motion resonance from radial velocity data, as a function of their masses, number of observations and the signal-to-noise ratio. Even for a data set of the order of 100 observations and standard deviations of the order of a few meters per second, we find that Jovian-size resonant planets are difficult to detect if the masses of the planets differ by a factor larger than similar to 4. This is consistent with the present population of real exosystems in the 2/1 commensurability, most of which have resonant pairs with similar minimum masses, and could indicate that many other resonant systems exist, but are currently beyond the detectability limit. Furthermore, we analyze the error distribution in masses and orbital elements of orbital fits from synthetic data sets for resonant planets in the 2/1 commensurability. For various mass ratios and number of data points we find that the eccentricity of the outer planet is systematically overestimated, although the inner planet`s eccentricity suffers a much smaller effect. If the initial conditions correspond to small-amplitude oscillations around stable apsidal corotation resonances, the amplitudes estimated from the orbital fits are biased toward larger amplitudes, in accordance to results found in real resonant extrasolar systems.

Mapping low- and high-density clouds in astrophysical nebulae by imaging forbidden line emission

Emission line ratios have been essential for determining physical parameters such as gas temperature and density in astrophysical gaseous nebulae. With the advent of panoramic spectroscopic devices, images of regions with emission lines related to these physical parameters can, in principle, also be produced. We show that, with observations from modern instruments, it is possible to transform images taken from density-sensitive forbidden lines into images of emission from high- and low-density clouds by applying a transformation matrix. In order to achieve this, images of the pairs of density-sensitive lines as well as the adjacent continuum have to be observed and combined. We have computed the critical densities for a series of pairs of lines in the infrared, optical, ultraviolet and X-rays bands, and calculated the pair line intensity ratios in the high- and low-density limit using a four- and five-level atom approximation. In order to illustrate the method, we applied it to Gemini Multi-Object Spectrograph (GMOS) Integral Field Unit (GMOS-IFU) data of two galactic nuclei. We conclude that this method provides new information of astrophysical interest, especially for mapping low- and high-density clouds; for this reason, we call it `the ld/hd imaging method`.

Possible signature of hypernova nucleosynthesis in a beryllium-rich halo dwarf

As part of a large survey of halo and thick disc stars, we found one halo star, HD106038, exceptionally overabundant in beryllium. In spite of its low metallicity, [Fe/H] = -1.26, the star has log(Be/H) = -10.60, which is similar to the solar meteoritic abundance, log(Be/H)=-10.58. This abundance is more than 10 times higher the abundance of stars with similar metallicity and cannot be explained by models of chemical evolution of the Galaxy that include the standard theory of cosmic ray spallation. No other halo star exhibiting such a beryllium overabundance is known. In addition, overabundances of Li, Si, Ni, Y and Ba are also observed. We suggest that all these chemical peculiarities, excepting the Ba abundance, can be simultaneously explained if the star was formed in the vicinity of a hypernova.

The impact of neurological illness on marital relationships

The current study investigated the impact of neurological illness on marital relationship satisfaction. Participants numbered 423 patients and 335 carers from motor neurone disease (MND), Huntington's disease (HD), Parkinson's, and multiple sclerosis (MS). The results demonstrated that patients and carers with HD had a significantly lower level of relationship satisfaction and sex life satisfaction than the other three illness groups. Further, patients with HD indicated a significantly higher level of relationship satisfaction than their carers. For MS and MND patients, social support predicted marital relationship satisfaction, and for Parkinson's patients, social support and sex life satisfaction predicted marital relationship satisfaction.

A comparison of mood and quality of life among people with progressive neurological illnesses and their caregivers

The current study was designed to investigate differences in mood and a range of QOL domains among 423 patients and 335 caregivers of people with motor neurone disease (MND), Huntington’s disease (HD), Parkinson’s, and multiple sclerosis (MS). Patients and caregivers completed an anonymous questionnaire that evaluated their mood (anxiety, depression, fatigue, confusion) and QOL (physical, psychological, social, environment). The results demonstrated that caregivers of people with MND and HD experienced most problems with their mood and QOL compared to caregivers of people in the other illness groups. There were few differences in mood or QOL between patients and caregivers. Patients generally showed greater confusion, physical impairment, and psychological maladjustment. The findings suggest that educational and intervention programs need to be developed to help both patients and their caregivers to adjust and cope with these illnesses, particularly caregivers of people with MND and HD.

Cortisol delays the estradiol-induced LH surge : is this dependent on prior ovarian steroid exposure?

Glucocorticoids can inhibit pulsatile LH secretion and can delay or even block the preovulatory LH surge. Previous work in ovariectomized ewes has indicated that cortisol can delay the estradiol-induced LH surge in an artificial follicular phase model but the results suggest this effect may be influenced by prior exposure to ovarian steroids. Here we tested the hypothesis that this disruptive effect of cortisol on the positive feedback action of estradiol is dependent on prior exposure to the ovarian steroidal milieu of the estrous cycle. Using long-term ovariectomized ewes, sequential artificial estrous cycles were created in the anestrous season by treatment and subsequent withdrawal of progesterone (CIDRs inserted for 9 d) followed by estradiol implants simulating the pre-ovulatory estradiol rise that induces the LH surge. Following the first artificial estrous cycle, a second cycle was initiated. Progesterone was again administered for 9 d followed by a second artificial follicular phase two weeks later. Beginning 2 hr prior to estradiol administration and ending at 40 hr, animals received either a cortisol infusion (elevate plasma levels to ∼170 ng/ml) or vehicle. Jugular blood was sampled hourly to assess occurrence and timing of the LH surge. Four different treatment sequences were tested (Cycle 1-Cycle 2): cortisol-cortisol; vehicle-cortisol; cortisol-vehicle; and vehicle-vehicle (n=5-6/sequence). If prior exposure to the ovarian steroidal milieu of the estrous cycle was necessary for cortisol to interfere with the positive feedback action of estradiol, then we would predict that cortisol would only delay the LH surge when it was delivered in Cycle 2 but not Cycle 1. Our results failed to support this prediction. Cortisol delayed the surge in both cycles (p<0.01), and the extent of the delay was the same in both Cycles 1 and 2 (4 hrs). Cortisol did not significantly affect surge amplitude in either cycle. These findings reinforce our previous conclusion that cortisol can delay the estradiol-induced LH surge but they do not support the hypothesis that this action of cortisol is dependent upon exposure to the ovarian steroidal milieu of the previous estrous cycle. (NIH-HD-30773)

A simple nutrition screening tool for hemodialysis nurses

Objective : To assess the reliability of a nurse-performed nutrition screening tool (NST) for hemodialysis (HD) patients to identify nutritionally at-risk patients.

Design : Tool reliability assessment.

Setting and Participants : The setting was nine non-hospital private (n = 3) and public (n = 6) HD units in Australia (two rural and seven metropolitan). Participants were 112 HD patients.

Results : A total of 112 HD patients (male = 65, female = 47) from 9 non-hospital HD units in Australia (seven metropolitan and two rural) were screened with the NST and the outcome of dietitian referral compared with Standard Dietitians Assessment. The mean age of patients was 57.6 years. Overall, the NST showed a sensitivity of 0.84 (range, 0.71 to 0.94; P < .05) and a specificity of 0.9 (range, 0.82 to 0.98; P < .05). The NST was more sensitive (sensitivity, 0.93 [range, 0.87 to 0.99; P < .05]) and was more specific for men (specificity, 0.92 [range, 0.85 to 0.99; P < .05]). Specificity was very strong in metropolitan patients (specificity, 0.94 [range, 0.87 to 1.01; P < .05]).

Conclusions : The tool was more sensitive and specific than the NST previously reported by the same investigators. The tool is particularly specific in that it screens those patients not requiring dietitian intervention. The use of this tool may benefit HD units that do not have on-site or regular dietetic support to prioritize patients needing dietitian intervention.

A haemodialysis nutritional screening tool for nurses : a pilot study

The purpose of the study was to pilot a nurse-performed nutritional screening tool (NST) for dialysis patients in order to identify nutritionally at-risk patients. Haemodialysis (HD) patients are at risk of nutritional-related problems. Nutritional screening by nurses may assist in the early recognition of and response to these problems. An NST was developed using 9 screening parameters. (BMI, weight change, poor appetite, GI symptoms, albumin, pre-dialysis urea, K+, PO4++, HbA1c). The NST was compared with Standard Dietitian Assessment (SDA). 44 HD patients were screened with the NST and then with SDA. The tool showed sensitivity of 0.7 (95%CI+/- 0.21) and a specificity of 0.77 (95%CI+/-0.16). Reliability was low (alpha = .18). Alpha increased to 0.32 if pre-dialysis urea was removed from the tool and increased to 0.48 if weight loss, appetite, K+ and PO4++ were used alone. The pilot study showed a low reliability of the NST compared with SDA. With further analysis and modifications, the NST has the potential to assist nutritional screening by nurses in dialysis centres that have limited dietetic access.

Serum levels of brain-derived neurotrophic factor in schizophrenia on a hypocaloric diet

Dietary factors influence BDNF in animal studies, but there is no comparable data in clinical populations. We examined the effect of a dietary intervention on BDNF serum levels in 67 DSM-IV schizophrenic outpatients (51 males and 16 females). Two groups were assessed in a cross-sectional study: one on a hypocaloric diet (HD) and the other not on a hypocaloric diet. Weight, height and BMI data were collected concurrently with 5-ml blood sampling of each subject. BDNF levels were measured with a sandwich-ELISA. The blood sample was obtained a minimum of one month after the exposure to dietary intervention. Serum BDNF levels were significantly higher in patients on the HD (p = 0.023). Additional research examining the interaction among patterns of nutritional food behavior and underlying physiopathology may result in insights upon which evidence-based decisions regarding dietary interventions can be made in people identified with major psychiatric disorders, such as schizophrenia.

Does the longer application of anodal-transcranial direct current stimulaton increase corticomotor excitability further? A pilot study

Introduction: Anodal transcranial direct current stimulation (a-tDCS) of the primary motor cortex (M1) has been shown to be effective in increasing corticomotor excitability.
　
Methods: We investigated whether longer applications of a-tDCS coincide with greater increases in corticomotor excitability compared to shorter application of a-tDCS. Ten right-handed healthy participants received one session of a-tDCS (1mA current) with shorter (10 min) and longer (10+10 min) stimulation durations applied to the left M1 of extensor carpi radialis muscle (ECR). Corticomotor excitability following application of a-tDCS was assessed at rest with transcranial magnetic stimulation (TMS) elicited motor evoked potentials (MEP) and compared with baseline data for each participant.
　
Results: MEP amplitudes were increased following 10 min of a-tDCS by 67% (p = 0.001) with a further increase (32%) after the second 10 min of a-tDCS (p = 0.005). MEP amplitudes remained elevated at 15 min post stimulation compared to baseline values by 65% (p = 0.02).
　
Discussion: The results demonstrate that longer application of a-tDCS within the recommended safety limits, increases corticomotor excitability with after effects of up to 15 minutes post stimulation.

Different current intensities of anodal transcranial direct current stimulation do not differentially modulate motor cortex plasticity

Transcranial direct current stimulation (tDCS) is a noninvasive technique that modulates the excitability of neurons within the motor cortex (M1). Although the aftereffects of anodal tDCS on modulating cortical excitability have been described, there is limited data describing the outcomes of different tDCS intensities on intracortical circuits. To further elucidate the mechanisms underlying the aftereffects of M1 excitability following anodal tDCS, we used transcranial magnetic stimulation (TMS) to examine the effect of different intensities on cortical excitability and short-interval intracortical inhibition (SICI). Using a randomized, counterbalanced, crossover design, with a one-week wash-out period, 14 participants (6 females and 8 males, 22–45 years) were exposed to 10 minutes of anodal tDCS at 0.8, 1.0, and 1.2 mA. TMS was used to measure M1 excitability and SICI of the contralateral wrist extensor muscle at baseline, immediately after and 15 and 30 minutes following cessation of anodal tDCS. Cortical excitability increased, whilst SICI was reduced at all time points following anodal tDCS. Interestingly, there were no differences between the three intensities of anodal tDCS on modulating cortical excitability or SICI. These results suggest that the aftereffect of anodal tDCS on facilitating cortical excitability is due to the modulation of synaptic mechanisms associated with long-term potentiation and is not influenced by different tDCS intensities.

A longitudinal study of quality of life among people living with a progressive neurological illness

This study investigated predictors of quality of life (QOL) of people with progressive neurological illnesses. Participants were 257 people with motor neurone disease (MND), Huntington’s disease (HD), multiple sclerosis (MS), or Parkinson’s. Participants completed questionnaires on two occasions, 12 months apart. There was an increase in severity of symptoms for people withMND, negative mood for people with HD and Parkinson’s, and social support satisfaction for people with MS. Regression analyses were conducted to determine predictors of QOL for each group. Predictor variables were length of illness, symptoms (physical symptoms, control over body, cognitive symptoms and psychological symptoms), mood, relationship satisfaction and social support. Predictors of QOL were severity of symptoms for people withMND, HD and MS; negative mood for people withMNDand Parkinson’s; and social support satisfaction for people with MS. These results demonstrate the importance of illness severity and mood in predicting QOL, but also indicate differences between illness groups. The limited role played by social support and relationship is a surprising finding from the current study.

How do Thai patients receiving haemodialysis cope with pain?

How do Thai patients adapt to haemodialysis?

The purpose of the current study was to understand the processes Thai people receiving HD used to adapt to CKD and its treatment. Religion, spirituality, social support and self-management were powerful coping strategies. These coping strategies were strongly influenced by Thai culture and other belief systems.

A case study illustrating therapist-assisted internet cognitive behavior therapy for depression

Randomized controlled trials show that therapist-assisted Internet cognitive behavior therapy (ICBT) is efficacious in the treatment of depression. Given that this is a novel way of delivering cognitive behavior therapy, however, clinical service providers may have questions about how to provide therapist-assisted ICBT in clinical practice, particularly with respect to therapist assistance. To exemplify this approach, we present a case study of an older adult male who received 12 modules of therapist-assisted ICBT for depression over the course of 5. months. Highlights of the therapeutic exchanges that occurred over email are provided to illustrate the type of information clients may share with therapists and the nature of therapist assistance. Treatment progress was assessed via self-report questionnaires measuring depression, anxiety, and adjustment. Consistent with the research evidence, significant improvement was observed on all symptom measures at posttreatment. Satisfaction with the therapist-assisted ICBT program and a strong therapeutic alliance was also reported. The case will expand clinician understanding of therapist-assisted ICBT and may serve to stimulate clinician interest in the provision of therapist-assisted ICBT. Future research directions stemming from this case are presented. © 2013 .