Characteristics of C-4 photosynthesis in stems and petioles of C-3 flowering plants

Most plants are known as C-3 plants because the first product of photosynthetic CO2 fixation is a three-carbon compound. C-4 plants, which use an alternative pathway in which the first product is a four-carbon compound, have evolved independently many times and are found in at least 18 families. In addition to differences in their biochemistry, photosynthetic organs of C-4 plants show alterations in their anatomy and ultrastructure. Little is known about whether the biochemical or anatomical characteristics of C-4 photosynthesis evolved first. Here we report that tobacco, a typical C-3 plant, shows characteristics of C-4 photosynthesis in cells of stems and petioles that surround the xylem and phloem, and that these cells are supplied with carbon for photosynthesis from the vascular system and not from stomata. These photosynthetic cells possess high activities of enzymes characteristic of C-4 photosynthesis, which allow the decarboxylation of four-carbon organic acids from the xylem and phloem, thus releasing CO2 for photosynthesis. These biochemical characteristics of C-4 photosynthesis in cells around the vascular bundles of stems of C-3 plants might explain why C-4 photosynthesis has evolved independently many times

A cluster randomised trial to assess the impact of clinical pathways on AMI management in rural Australian emergency departments

Background. People living in rural Australia are more likely to die in hospital following an acute myocardial infarction than those living in major cities. While several factors, including time taken to access hospital care, contribute to this risk, it is also partially attributable to the lower uptake of evidence-based guidelines for the administration of thrombolytic drugs in rural emergency departments where up to one-third of eligible patients do not receive this life-saving intervention. Clinical pathways have the potential to link evidence to practice by integrating guidelines into local systems, but their impact has been hampered by variable implementation strategies and sub-optimal research designs. The purpose of this study is to determine the impact of a five-step clinical pathways implementation process on the timely and efficient administration of thrombolytic drugs for acute myocardial infarctions managed in rural Australian emergency departments. Methods/Design. The design is a two-arm, cluster-randomised trial with rural hospital emergency departments that treat and do not routinely transfer acute myocardial infarction patients. Six rural hospitals in the state of Victoria will participate, with three in the intervention group and three in the control group. Intervention hospitals will participate in a five-step clinical pathway implementation process: engagement of clinicians, pathway development according to local resources and systems, reminders, education, and audit and feedback. Hospitals in the control group will each receive a hard copy of Australian national guidelines for chest pain and acute myocardial infarction management. Each group will include 90 cases to give a power of 80% at 5% significance level for the two primary outcome measures: proportion of those eligible for thrombolysis receiving the drug and time to delivery of thrombolytic drug. Discussion. Improved compliance with thrombolytic guidelines via clinical pathways will increase acute myocardial infarction survival rates in rural hospitals and thereby help to reduce rural-urban mortality inequalities. Such knowledge translation has the potential to be adapted for a range of clinical problems in a wide array of settings. Trial registration. Australia New Zealand Clinical Trials Registry code ACTRN12608000209392

The Eyes Have It: Sex and Sexual Orientation Differences in Pupil Dilation Patterns

Recent research suggests profound sex and sexual orientation differences in sexual response. These results, however, are based on measures of genital arousal, which have potential limitations such as volunteer bias and differential measures for the sexes. The present study introduces a measure less affected by these limitations. We assessed the pupil dilation of 325 men and women of various sexual orientations to male and female erotic stimuli. Results supported hypotheses. In general, self-reported sexual orientation corresponded with pupil dilation to men and women. Among men, substantial dilation to both sexes was most common in bisexual-identified men. In contrast, among women, substantial dilation to both sexes was most common in heterosexual-identified women. Possible reasons for these differences are discussed. Because the measure of pupil dilation is less invasive than previous measures of sexual response, it allows for studying diverse age and cultural populations, usually not included in sexuality research

Economic burden of neural tube defects and impact of prevention with folic acid: a literature review

Neural tube defects (NTDs) are the second most common group of serious birth defects. Although folic acid has been shown to reduce effectively the risk of NTDs and measures have been taken to increase the awareness, knowledge, and consumption of folic acid, the full potential of folic acid to reduce the risk of NTDs has not been realized in most countries. To understand the economic burden of NTDs and the economic impact of preventing NTDs with folic acid, a systematic review was performed on relevant studies. A total of 14 cost of illness studies and 10 economic evaluations on prevention of NTDs with folic acid were identified. Consistent findings were reported across all of the cost of illness studies. The lifetime direct medical cost for patients with NTDs is significant, with the majority of cost being for inpatient care, for treatment at initial diagnosis in childhood, and for comorbidities in adult life. The lifetime indirect cost for patients with spina bifida is even greater due to increased morbidity and premature mortality. Caregiver time costs are also significant. The results from the economic evaluations demonstrate that folic acid fortification in food and preconception folic acid consumption are cost-effective ways to reduce the incidence and prevalence of NTDs. This review highlights the significant cost burden that NTDs pose to healthcare systems, various healthcare payers, and society and concludes that the benefits of prevention of NTDs with folic acid far outweigh the cost. Further intervention with folic acid is justified in countries where the full potential of folic acid to reduce the risk of NTDs has not been realized

Factors associated with early menarche: results from the French Health Behaviour in School-aged Children (HBSC) study

<p>Abstract</p> <p>Background</p> <p>Puberty is a transition period making physiological development a challenge adolescents have to face. Early pubertal development could be associated with higher risks of poor health. Our objective was to examine risk behaviours, physical and psychological determinants associated with early menarche (<11 years).</p> <p>Methods</p> <p>Early menarche was assessed in the Health Behaviour in School-aged Children French cross-sectional survey. Data were collected in 2006 by anonymous self-reported standardized questionnaire from a nationally representative sample of 1072 15 years old girls in school classrooms. Family environment, school experience, physical and psychological factors, risk behaviours (substance use and sexual initiation) were recorded. Logistic regression models were applied (analysing for crude and adjusted relationships between early menarche and risk behaviours controlled for family context).</p> <p>Results</p> <p>Median age at menarche was 13.0 years; 57 girls (5.3%) were early-matured. Controlled for familial environment, early menarche was associated with having had more than two life-drunkenness episodes (adjusted OR = 2.5 [1.3-4.6]), early sexual initiation (adjusted OR = 2.8 [1.3-6.0]) and overweight (adjusted OR = 7.3 [3.6-14.9]).</p> <p>Conclusion</p> <p>Early-maturing girls may affiliate with older adolescents, hence engage in risk behaviours linked to their appearance rather than their maturity level. Factors associated with early menarche highlight the need to focus attention on early-matured girls to prevent further health problems linked to risk behaviours.</p

Oral and anal sex practices among high school youth in Addis Ababa, Ethiopia

<p>Abstract</p> <p>Background</p> <p>Understanding the full range of sexual behaviors of young people is crucial in developing appropriate interventions to prevent and control sexually transmitted infections including HIV. However, such information is meager in developing countries. The objective of this study was to describe oral and anal sex practices and identify associated factors among high school youth.</p> <p>Methods</p> <p>A cross-sectional study was conducted among high school youth in Addis Ababa, Ethiopia. A multi-stage sampling procedure was followed to select a representative sample of school youth. The total sample size for this study was 3840. Data were collected using a self-administered questionnaire. Data analysis was guided by the ecological framework.</p> <p>Results</p> <p>The overall proportion of people who reported ever having oral sex was 5.4% (190) and that of anal sex was 4.3% (154). Of these 51.6% (98) had oral sex and 57.1% (87) had anal sex in the past 12 months. Multiple partnerships were reported by 61.2% of the respondents who had oral sex and 51.1% of students practicing anal sex. Consistent condom use was reported by 12.2% of those practicing oral sex and 26.1% of anal sex. Reasons for oral and anal sex included prevention of pregnancy, preserving virginity, and reduction of HIV and STIs transmission. Oral sex practice was strongly and significantly associated with perception of best friends engagement in oral sex (AOR = 5.7; 95% CI 3.6-11.2) and having illiterate mothers (AOR = 11.5; 95%CI 6.4-18.5). Similarly, anal sex practice was strongly and significantly associated with favorable attitude towards anal sex (AOR = 6.2; 95%CI 3.8-12.4), and perceived best friends engagement in anal sex (AOR = 9.7; 95%CI 5.4-17.7).</p> <p>Conclusion</p> <p>Considerable proportion of adolescents had engaged in oral and anal sex practices. Multiple sexual partnerships were common while consistent condom use was low. Sexual health education and behavior change communication strategies need to cover a full range of sexual practices.</p

Integrating community health assistant- driven sexual and reproductive health services in the community health system in Nyimba district in Zambia: Mapping key actors, points of integration, and conditions shaping the process

Introduction: Although large scale public sector community health worker programs have been key in providing sexual and reproductive health (SRH) services in low- and middle-income countries, their integration process into community health systems is not well understood. This study aimed to identify the conditions and strategies through which Community Health Assistants (CHAs) gained entry and acceptability into community health systems to provide SRH services to youth in Zambia. The country’s CHA program was launched in 2010. Methodology: A phenomenological design was conducted in Nyimba district. All nine CHAs deployed in Nyimba district were interviewed in-depth on their experiences of navigating the introduction of SRH services for youth in community settings, and the data obtained analyzed thematically. Results: In delivering SRH services targeting youth, CHAs worked with a range of community actors, including other health workers, safe motherhood action groups, community health workers, neighborhood health committees, teachers, as well as political, traditional and religious leaders. CHAs delivered SRH education and services in health facilities, schools, police stations, home settings, and community spaces. They used their health facility service delivery role to gain trust and entry into the community, and they also worked to build relationships with other community level actors by holding regular joint meetings, and acting as brokers between the volunteer health workers and the Ministry of Health. CHAs used their existing social networks to deliver SRH services to adolescents. By embedding the provision of information about SRH into general life skills at community level, the topic’s sensitivity was reduced and its acceptability was enhanced. Further, support from community leaders towards CHA-driven services promoted the legitimacy of providing SRH for youth. Factors limiting the acceptability of CHA services included the taboo of discussing sexuality issues, a gender discriminatory environment, competition with other providers, and challenges in conducting household visits

Nonlinear wave interaction in coastal and open seas -- deterministic and stochastic theory

We review the theory of wave interaction in finite and infinite depth. Both of these strands of water-wave research begin with the deterministic governing equations for water waves, from which simplified equations can be derived to model situations of interest, such as the mild slope and modified mild slope equations, the Zakharov equation, or the nonlinear Schr\"odinger equation. These deterministic equations yield accompanying stochastic equations for averaged quantities of the sea-state, like the spectrum or bispectrum. We discuss several of these in depth, touching on recent results about the stability of open ocean spectra to inhomogeneous disturbances, as well as new stochastic equations for the nearshore

Holoprosencephaly

Holoprosencephaly (HPE) is a complex brain malformation resulting from incomplete cleavage of the prosencephalon, occurring between the 18th and the 28th day of gestation and affecting both the forebrain and the face. It is estimated to occur in 1/16,000 live births and 1/250 conceptuses. Three ranges of increasing severity are described: lobar, semi-lobar and alobar HPE. Another milder subtype of HPE called middle interhemispheric variant (MIHF) or syntelencephaly is also reported. In most of the cases, facial anomalies are observed in HPE, like cyclopia, proboscis, median or bilateral cleft lip/palate in severe forms, ocular hypotelorism or solitary median maxillary central incisor in minor forms. These latter midline defects can occur without the cerebral malformations and then are called microforms. Children with HPE have many medical problems: developmental delay and feeding difficulties, epilepsy, instability of temperature, heart rate and respiration. Endocrine disorders like diabetes insipidus, adrenal hypoplasia, hypogonadism, thyroid hypoplasia and growth hormone deficiency are frequent. To date, seven genes have been positively implicated in HPE: Sonic hedgehog (SHH), ZIC2, SIX3, TGIF, PTCH, GLI2 and TDGF1. A molecular diagnosis can be performed by gene sequencing and allele quantification for the four main genes SHH, ZIC2, SIX3 and TGIF. Major rearrangements of the subtelomeres can also be identified by multiplex ligation-dependent probe amplification (MLPA). Nevertheless, in about 70% of cases, the molecular basis of the disease remains unknown, suggesting the existence of several other candidate genes or environmental factors. Consequently, a "multiple-hit hypothesis" of genetic and/or environmental factors (like maternal diabetes) has been proposed to account for the extreme clinical variability. In a practical approach, prenatal diagnosis is based on ultrasound and magnetic resonance imaging (MRI) rather than on molecular diagnosis. Treatment is symptomatic and supportive, and requires a multidisciplinary management. Child outcome depends on the HPE severity and the medical and neurological complications associated. Severely affected children have a very poor prognosis. Mildly affected children may exhibit few symptoms and may live a normal life