Intergroup resource allocation among children from minority and majority groups in three settings of former conflict

Intergroup resource allocation was examined among 333 children aged 7-11 (51.9% female) within three settings of former intergroup conflict (January-June 2021). Children represented both ethno-religious minority and majority groups (Republic of North Macedonia: Albanians, Macedonians; Croatia: Serbs, Croats; Northern Ireland: Catholics, Protestants), from predominantly White and middle-class families. Ingroup bias in average resource allocation amounts was demonstrated by both minority and majority children, across settings, in the context of novel targets (historic conflict rivals). Majority children were also more likely to give equally (which maintains the status quo) than minority children. Giving equally increased with age for both minority and majority children, despite being in "zero-sum," conflict settings. Equitable intergroup resource allocation in such settings has implications for conflict transformation.

Tunable dual optical frequency comb at 2 μm for CO2 sensing

In this article, we demonstrate a dual frequency comb (DFC) based on the gain-switching of mutually injection-locked semiconductor lasers in the 2 μm wavelength region with a tunable free spectral range (FSR) between 500 MHz and 3 GHz. Through the down-conversion process enabled by DFCs, the beating spectra of the optical frequency combs were captured in a 15 MHz electrical bandwidth with high resolution and millisecond acquisition times. A first experimental demonstration of sensing CO₂ with this architecture is also presented.

Gain-switched dual frequency comb at 2 µm

This article shows a dual frequency comb in the 2 µm wavelength region using mutually injection locked gain-switched semiconductor lasers. Strained InGaAs multi-quantum-well discrete mode lasers and gain switching were used to generate two optical frequency combs with repetition rates of 2 GHz and 2.0001 GHz respectively, centred at 2.002 µm. Each optical comb spanned approximately 100 GHz. Through mutual injection locking to an edge comb line common in both combs, a phase locked dual frequency comb was demonstrated with 44 beating tones unique to single comb line pair interactions. This scheme allows for the comb information to be compressed into a 5 MHz detection bandwidth and captured with millisecond acquisition times, which could be of benefit to a number of sensing applications.

Integrated demultiplexing and amplification of coherent optical combs

The explosive growth of the internet during the last few decades has been enabled by two complementary innovations in optical communications: the use of multiple optical channels within a single optical fibre, and the increase in the bandwidth of individual channels to hundreds of Gbps. Further increases in overall bandwidth look to be provided by more spectrally efficient optical superchannels that use coherent sub-carriers generated using optical orthogonal frequency division multiplexing (OFDM). Yet, a cost effective way of generating these signals has not been demonstrated. One crucial, but missing piece is an effective means to separate the closely frequency spaced optical sub-carriers from the coherent optical comb before placing information on each sub-carrier, and thus creating the OFDM signal. Here, we demonstrate a flexible strategy implemented in a compact photonic integrated circuit (PIC) that is used to separate and amplify these sub-carriers using on-chip injection locking.

Key enabling technologies for optical communications at 2000 nm

This paper discusses the potential for opening a new wavelength window at the 2 μm waveband for optical communications, showing current limitations of the system's performance. It focuses on novel results for key enabling technologies, including the analysis of laser injection locking at this waveband, an improved responsivity for bulk and strained InGaAs edge-couple detectors, and also an increased gain profile for thulium-doped fiber amplifiers.

Insomnia, psychiatric disorders and suicidal ideation in a National Representative Sample of active Canadian Forces members

BACKGROUND

Past research on the association between insomnia and suicidal ideation (SI) has produced mixed findings. The current study explored the relationship between insomnia, SI, and past-year mental health status among a large Canadian Forces (CF) sample.

METHOD

Data was obtained from the 2013 Canadian Forces Mental Health Survey (CFMHS), and included a large representative sample of Canadian Regular Forces personnel (N = 6700). A series of univariate logistic regressions were conducted to test individual associations between past-year mental health status, insomnia, and potential confounds and SI. Mental health status included three groups: 0, 1, or two or more probable diagnoses of posttraumatic stress disorder (PTSD), major depressive disorder (MDD), generalized anxiety disorder (GAD), panic disorder (PD) and alcohol abuse/dependence. Stepwise multivariate logistic regression was used to assess the relationship between insomnia and SI with mental health status as a moderator.

RESULTS

40.8% of respondents reported experiencing insomnia. Both insomnia and number of mental health conditions incrementally increased the risk of SI. However, past-year mental health status was a significant moderator of this relationship, such that for CF personnel with either no (AOR = 1.61, 1.37-1.89) or only one past-year mental health condition (AOR = 1.39, 1.12-1.73), an incremental increase in insomnia was associated with an increased likelihood of SI. However, in personnel with two or more past-year mental health disorders, insomnia was no longer significantly associated with SI (AOR = 1.04, 0.81-1.33).

CONCLUSIONS

Insomnia significantly increased the odds of SI, but only among individuals with no or one mental health condition. Findings highlight the importance of assessing insomnia among CF members in order to further suicide prevention efforts.

Epilepsy, birth weight and academic school readiness in Canadian children: Data from the national longitudinal study of children and youth

PURPOSE

Birth weight is an important indicator of prenatal/in-utero environment. Variations in birth weight have been reportedly associated with risks for cognitive problems. The National Longitudinal Survey of Children and Youth (NLSCY) dataset was explored to examine relationships between birth weight, academic school readiness and epilepsy.

METHODS

A population based sample of 32,900 children of the NLSCY were analyzed to examine associations between birth weight, and school readiness scores in 4-5-year-old children. Logistic and Linear regression was used to examine associations between having epilepsy and these outcomes. Gestation data was available on 19,867 children, full-term children represented 89.67% (gestation >259days), while 10.33% of children were premature (gestation <258days). There were 20 children with reported epilepsy in the sample. Effects of confounding variables (diabetes in pregnancy, smoking in pregnancy, high blood pressure during pregnancy, and gender of the infant) on birth weight and epilepsy were controlled using a separate structural equation model.

RESULTS

Logistic regression analysis identified an association between epilepsy and lower birth weights, as well as an association between lower birth weight, having epilepsy and lower PPVT-R Scores. Model results show the relationship between low birth weight and epilepsy remains statistically significant even when controlling for the influence of afore mentioned confounding variables.

CONCLUSION

Low birth weight appears to be associated with both epilepsy and academic school readiness. The data suggest that an abnormal prenatal environment can influence both childhood onset of epilepsy and cognition. Additional studies with larger sample sizes are needed to verify this relationship in detail.

Epilepsy and its Impact on psychosocial outcomes in Canadian children: Data from the National Longitudinal Study of Children and Youth (NLSCY)

PURPOSE

The purpose of this study was to use data from a population-based survey to evaluate the association between childhood epilepsy and social outcomes through tests of mathematics skills, and sense of general self-esteem (GSS).

METHODS

Using data from Cycles 1 to 8 of the National Longitudinal Survey of Children and Youth (NLSCY), Hierarchical linear modeling (HLM) was used to compare baseline math scores and changes in math scores and sense of general self esteem (GSS) over time in children with and without epilepsy. Scores of Health Utility Index (HUI) were factored into the analysis.

RESULTS

Children with epilepsy do not significantly differ in their scaled math scores in comparison to their peers without epilepsy, at age 12; however, in the two level HLM model the children with epilepsy lagged behind the healthy comparison group in terms of their growth in acquiring knowledge in mathematics. Additionally, when children with epilepsy carry an added health impairment as measured by an imperfect health utility (HUI) score the group shows a slower rate of growth in their math scores over time. Self-esteem measures show variable effects in children with epilepsy alone, and those with added health impairments. The interaction with HUI scores shows a significant negative effect on self-esteem, when epilepsy is associated with added health impairment.

CONCLUSION

The findings suggest that the population of Canadian children surveyed with epilepsy are vulnerable to poorer academic outcomes in mathematics in later years, and this problem is compounded further with the presence of other additional health impairments.

Monolithically integrated low linewidth comb source using gain switched slotted Fabry-Perot lasers

A monolithically integrated low linewidth optical comb is demonstrated by gain switching of a three-section laser device. The device consists of a slave and master section separated by a shared slotted mirror section. Wavelength tunability has been demonstrated by varying the electrical bias of each section. The number of comb lines is shown to almost double with the addition of optical injection from the master section into the slave. The unmodulated device has a full width half max linewidth of ∼ 500 kHz, while the comb line set were measured to be ∼ 600 kHz, with little degradation as a result of gain switching. The FSR (free spectral range) of the demonstrated comb is 4 GHz, which is tunable within the bandwidth of the device, with a central wavelength of 1580.3 nm.

Wheatstone bridge configuration for evaluation of plasmonic energy transfer

We propose an internal (on-chip) Wheatstone bridge configuration to evaluate the efficiency of near-field transducers (NFT) as used in heat-assisted magnetic recording (HAMR). The electric field enhancement between the transducer and the image plane is monitored by measuring the resistance of metal electrodes composing the image plane. The absorption of the enhanced electric field causes an increase in the metal temperature, and thereby, in its resistance whose variation is monitored with an internal Wheatstone bridge which is accurately balanced in the absence of the electric field.

Dense WDM transmission at 2 μm enabled by an arrayed waveguide grating

We show, for the first time, dense WDM (8×20  Gbit/s) transmission at 2 μm enabled by advanced modulation formats (4-ASK Fast-OFDM) and the development of key components, including a new arrayed waveguide grating (AWGr) at 2 μm. The AWGr shows -12.8±1.78  dB of excess loss with an 18-dB extinction ratio and a thermal tunability of 0.108 nm/°C.

10 Gb/s InP-based Mach-Zehnder modulator for operation at 2 μm wavelengths

We report on the first InP-based Mach-Zehnder modulator (MZM) employing quantum-confined Stark effect (QCSE) for operation around 2000 nm. The polarization sensitive device is based on 15 compressively strained quantum wells and achieves an electro-optic (EO) bandwidth of at least 9 GHz, with a DC extinction ratio of ~9 dB, and a V(π)L ~9.6 V.mm. We demonstrate back-to-back communication with a 10 Gb/s pseudo-random bit sequence (PRBS) of length 2(7)-1 at a wavelength around 2000 nm.

100 Gbit/s WDM transmission at 2 µm: transmission studies in both low-loss hollow core photonic bandgap fiber and solid core fiber

We show for the first time 100 Gbit/s total capacity at 2 µm waveband, using 4 × 9.3 Gbit/s 4-ASK Fast-OFDM direct modulation and 4 × 15.7 Gbit/s NRZ-OOK external modulation, spanning a 36.3 nm wide wavelength range. WDM transmission was successfully demonstrated over 1.15 km of low-loss hollow core photonic bandgap fiber (HC-PBGF) and over 1 km of solid core fiber (SCF). We conclude that the OSNR penalty associated with the SCF is minimal, while a ~1-2 dB penalty was observed after the HC-PBGF probably due to mode coupling to higher-order modes.

First demonstration of a 2μm few-mode TDFA for mode division multiplexing

We report the first demonstration of an inline few-mode thulium doped fiber amplifier (TDFA) operating at 2μm for mode division multiplexed transmission. Similar gain and noise figure performance for both the LP(01) and LP(11) modes are obtained in a cladding pumped 2-mode group TDFA. A maximum gain of 18.3dB was measured at 1970nm with a 3dB gain bandwidth of 75nm while the average noise figure was measured to be between 7 and 8dB for wavelengths longer than 1970nm.

20 × 960-Gb/s Space-division-multiplexed 32QAM transmission over 60 km few-mode fiber

We show transmission of 20 wavelength-division-multiplexed (WDM) × 960-Gb/s space-division-multiplexed 32QAM modulated channels (spectral efficiency (SE) of 15 bits/s/Hz) over 60 km of few-mode fiber (FMF) with inline few-mode EDFA (FM-EDFA). Soft-decision FEC was implemented and used to achieve error-free transmission.

On-chip optical phase locking of single growth monolithically integrated Slotted Fabry Perot lasers

This work investigates the optical phase locking performance of Slotted Fabry Perot (SFP) lasers and develops an integrated variable phase locked system on chip for the first time to our knowledge using these lasers. Stable phase locking is demonstrated between two SFP lasers coupled on chip via a variable gain waveguide section. The two lasers are biased differently, one just above the threshold current of the device with the other at three times this value. The coupling between the lasers can be controlled using the variable gain section which can act as a variable optical attenuator or amplifier depending on bias. Using this, the width of the stable phase locking region on chip is shown to be variable.

Three mode Er3+ ring-doped fiber amplifier for mode-division multiplexed transmission

We successfully fabricate three-mode erbium doped fiber with a confined Er(3+) doped ring structure and experimentally characterize the amplifier performance with a view to mode-division multiplexed (MDM) transmission. The differential modal gain was effectively mitigated by controlling the relative thickness of the ring-doped layer in the active fiber and pump launch conditions. A detailed study of the modal gain properties, amplifier performance in a MDM transmission system and inter-modal cross-gain modulation and associated transient effects is presented.

73.7 Tb/s (96 x 3 x 256-Gb/s) mode-division-multiplexed DP-16QAM transmission with inline MM-EDFA

Transmission of a 73.7 Tb/s (96 x 3 x 256-Gb/s) DP-16QAM mode-division-multiplexed signal over 119 km of few-mode fiber transmission line incorporating an inline multi mode EDFA and a phase plate based mode (de-)multiplexer is demonstrated. Data-aided 6 x 6 MIMO digital signal processing was used to demodulate the signal. The total demonstrated net capacity, taking into account 20% of FEC-overhead and 7.5% additional overhead (Ethernet and training sequences), is 57.6 Tb/s, corresponding to a spectral efficiency of 12 bits/s/Hz.

Plasmonic mediated interactions between waveguides and nanostructured metal surfaces

We present the polarization resolved, angular dependent, optical reflectance properties for single TE mode optical waveguides in contact with a nanostructured gold surface. A substantial angle dependent resonant decrease in the TE polarized surface reflectivity is measured which cannot be explained by a simple waveguide coupling due to surface roughness. Rather we show that the resonance is due to the excitation of a coupled waveguide-plasmonic surface mode created by the interaction between the metal nanostructure and the waveguide. A model based on coupled mode theory is introduced in order to explain the experimental data.

Processing affective stimuli in children with attention-deficit hyperactivity disorder

Neuropsychological investigations have suggested a contribution of right hemisphere dysfunction in attention-deficit hyperactivity disorder (ADHD). Right hemisphere dysfunction has been implicated in deficits of attention, motor impersistence, and processing emotion-laden stimuli. The current study investigated the ability of ADHD children to perceive emotional stimuli in the form of facial expressions and speech intonation. The subjects consisted of 37 ADHD and 37 control children aged 7 to 12 years. ANCOVA analysis indicated that ADHD children demonstrate mild-to-moderate deficits in the perception of affect. Furthermore, deficits in attention may contribute to inaccurate or incomplete encoding of stimulus properties. The results lend tentative support for the notion that the right cerebral hemisphere may play a critical role in ADHD.

Experimental observation of traveling waves in the transverse section of a laser

The selection of a transverse traveling wave by an inhomogeneous pump profile has been experimentally observed in a class B laser structure. The laser structure consisted of a wide-aperture edge-emitting laser diode operating in pulsed mode to avoid thermal guiding effects. The injection current's profile was modified from the usual top-hat configuration to a Lorentzian-like profile by the inclusion of a 10-mum p-type expitaxial spreading layer. Spatial dependance of the far field on the near field was observed. The same behavior is also demonstrated numerically by use of Maxwell-Bloch equations for semiconductor lasers.

A double-blind, placebo-controlled crossover study investigating the effect of porcine secretin in children with autism

A recent patient series reported the incidental findings of improved social and language skills in 3 children with autistic spectrum disorders after the administration of secretin, a peptide hormone. However, a subsequent study did not find evidence for a drug effect. Parents are seeking treatment with secretin despite the absence of empirical investigations demonstrating amelioration in autism symptomology. In order to more precisely measure the effects of secretin, this study investigated the effect of a single intravenous dose of porcine secretin on 12 autistic children through a randomized, double-blind, placebo-controlled, crossover study. Children were assessed on objective language and on social, neuropsychological, and gastrointestinal measures to evaluate drug effects. The study was conducted over a 16-week trial. The results indicated that significant differences were not observed on the majority of the dependent variables. Statistically significant differences were observed on measures of positive affect and activity level following secretin infusion. In general, the autistic children did not demonstrate the improvements described in the initial retrospective report.

Neuropsychological performance of adults evidencing Attention-Deficit Hyperactivity Disorder

Attention-Deficit Hyperactivity Disorder (ADHD) is no longer believed to be a time-limited syndrome manifested in and restricted to childhood and adolescence. Many of the characteristics associated with the disorder continue in variable form into adulthood. This investigation focused on two measures sensitive to attention, cognitive flexibility, and visual and auditory distraction, to determine if individuals diagnosed with ADHD would perform poorly in comparison with normal control subjects. Forty-two subjects, 27 ADHD adults and 15 control subjects, were administered the Goldman-Fristoe-Woodcock Test of Auditory Discrimination (TOAD), and the Stroop Color and Word Test. The findings indicated that the TOAD Noise subtest significantly discriminated the subjects, resulting in an overall correct classification rate of 80.95%.

Fatal halothane poisoning during anesthesia with other agents

A patient was inadvertently overdosed with halothane during the nitrous oxide phase of anesthesia induction. During the subsequent 2 1/2-h resuscitation attempt, the oxygen via the anesthesia machine continued to be contaminated with 5% halothane. Brain death was pronounced when the patient may have been only very deeply anesthetized. The vaporizer had accidentally been left on the full ON position prior to the procedure. Poor design of vaporizer controls and operator neglect combined to allow protracted patient exposure to the toxic concentration of halothane. The medical examiner has a critical role in the adequate management of anesthesia/surgery related deaths.