Design and optimization of THz coupling in zirconia MAS rotors for dynamic nuclear polarization NMR.

We present 3D electromagnetic simulations of the coupling of a 250 GHz beam to the sample in a 380 MHz DNP NMR spectrometer. To obtain accurate results for magic angle spinning (MAS) geometries, we first measured the complex dielectric constants of zirconia, sapphire, and the sample matrix material (DNP juice) from room temperature down to cryogenic temperatures and from 220 to 325 GHz with a VNA and up to 1 THz with a THz TDS system. Simulations of the coupling to the sample were carried out with the ANSYS HFSS code as a function of the rotor wall material (zirconia or sapphire), the rotor wall thickness, and the THz beam focusing (lens or no lens). For a zirconia rotor, the B1 field in the sample was found to be strongly dependent on the rotor wall thickness, which is attributed to the high refractive index of zirconia. The optimum thickness of the wall is likely due to a transmission maximum but is offset from the thickness predicted by a simple calculation for a flat slab of the wall material. The B1 value was found to be larger for a sapphire rotor than for a zirconia rotor for all cases studied. The results found in this work provide new insights into the coupling of THz radiation to the sample and should lead to improved designs of future DNP NMR instrumentation.

Ethical Dilemmas and Countertransference in Legally Mandated Reporting of Fatal Child Neglect.

In the fall of 2019, a much-publicized court case brought to national attention the issues of patient-doctor confidentiality when it comes to reporting the deaths of newborns in the United States. It is unclear whether the recent overturning of Roe v. Wade will lead to more cases like this. This article discusses issues of countertransference, as well as the ethical and legal implications were it to be a psychiatrist, in active treatment of such a patient, who would be required to make such a report. More specifically, as in the publicized court case, the patient could be a minor at the time, receiving treatment from a child psychiatrist. The implications of such a case include how countertransference affects the perception of fatal child neglect compared to intentional neonaticide; the ethical dilemma of generating a mandated report with the goal of child safety when such a report could lead to real legal consequences for a minor child; and considerations regarding continued treatment of a patient after such a report is made. It is likely that countertransference, shaped by attitudes toward mothers and idealized views on mothering, may play a large role in all these circumstances.

Measurement of Time Dependent Reflection, Transmission, and Absorption in Laser Driven Silicon and GaAs Switches for 250 GHz Radiation.

The reflectance (R) and transmittance (T) of Si and GaAs wafers irradiated by a 6 ns pulsed, 532 nm laser have been studied for s- and p-polarized 250 GHz radiation as a function of laser fluence and time. The measurements were carried out using precision timing of the R and T signals, allowing an accurate determination of the absorptance (A) where A=1-R-T. Both wafers had a maximum reflectance above 90% for a laser fluence ≥8 mJ/cm2. Both also showed an absorptance peak of ~50% lasting ~2 ns during the risetime of the laser pulse. Experimental results were compared with a stratified medium theory using the Vogel model for the carrier lifetime and the Drude model for permittivity. Modeling showed that the large absorptance at the early part of the rise of the laser pulse was due to the creation of a lossy, low carrier density layer. For Si, the measured R, T and A were in very good agreement with theory on both the nanosecond time scale and the microsecond scale. For GaAs, the agreement was very good on the nanosecond scale but only qualitatively correct on the microsecond scale. These results may be useful for planning applications of laser driven semiconductor switches.

PTSD Following Suicide Attempts in Adolescents: a Case Series.

The Diagnostic and Statistical Manual (DSM) does not specifically identify one's own suicide attempt as a potential source of trauma for the development of posttraumatic stress disorder (PTSD). PTSD following a near death experience in an adolescent may occur in both the adolescent and the parent. However, suicide-attempt-related PTSD (SA-PTSD) is scarce in the literature, particularly in the pediatric population. The authors review three cases of adolescent patients or their parents in an outpatient clinical practice who displayed varying severity of SA-PTSD symptoms. Information was obtained via self-report by adolescent, parent, or both. Screening for SA-PTSD symptoms was not explicitly sought; rather patients or parents volunteered such information de novo during clinical encounters which was then explored further. One adolescent had only brief PTSD-like experiences that faded with time and did not require intervention. A second adolescent reported long-term memory loss around the circumstances of their suicide attempt that may be related to medical morbidity; their parent had significant PTSD symptoms throughout treatment, and the parent was referred to their own therapy. A third adolescent was referred for cognitive-behavioral therapy (CBT) for the treatment of pervasive PTSD symptoms from a previous suicide attempt, with symptoms improving after treatment. A qualititative analysis suggests that more severe SA-PTSD symptoms are associated with 1) multiple prior suicide attempts; 2) more severe/higher morbidity suicide attempt; and 2) previous diagnosis of PTSD in patient or parent. Assessment for SA-PTSD is important to ensure that affected patients and their families are referred for appropriate resources and treatment. Of the very small sample of three cases, two required specific referral to treat PTSD symptoms in either the adolescent or the parent. The literature about SA-PTSD is extremely scarce. Only two studies systematically examined PTSD following suicide attempt, and none of these studies were in pediatric patients, making more robust quantitative or qualitative analysis limited at this time. Therefore, more research regarding epidemiology, risk factors, and treatment is needed.

Using the Psychiatry Resident-In-Training Examination (PRITE) to Assess the Psychiatry Medical Knowledge Milestones in Psychiatry.

OBJECTIVE: The introduction of the Milestone Project underscored the need for objective assessments of resident progress across the competencies. Therefore, the authors examined the Psychiatry Resident-In-Training Examination (PRITE) utility for measuring improvements in medical knowledge (MK). METHODS: The authors compared the mean performance for each MK subcompetency by resident year for all residents taking the PRITE from 2015 to 2017 (18,175 examination administrations). In addition, they surveyed psychiatry residency program directors regarding how well they thought they teach these subcompetencies. RESULTS: Increases in MK subcompetencies by resident year were significant for Psychopathology (p < 0.003), Psychotherapy (p < 0.002), and Somatic Therapies (p < 0.000). Development, Clinical Neuroscience, and Practice of Psychiatry did not show statistically significant differences between postgraduate years. Eighty psychiatry program directors responded to the survey and felt optimistic about their ability to teach the Psychopathology, Psychotherapy, Somatic Therapies, and Practice of Psychiatry subcompetencies. CONCLUSIONS: The PRITE measured significant improvements in medical knowledge for several of the core subcompetencies. The program director's responses would suggest that the lack of statistically significant differences found for Development and Clinical Neuroscience reflects areas in need of curricular development. The disparity between PRITE performance and program director perception of the Practice of Psychiatry subcompetency may reflect difficulties in defining the scope of this subcompetency. Overall, this suggests that structured examinations help measure improvements in certain subcompetencies and may also help identify curricular needs. However, there may be potential problems with the definition of some subcompetencies.

New York State dairy veterinarians' perceptions of antibiotic use and resistance: A qualitative interview study.

Antimicrobial resistance (AMR) limits the ability to prevent and treat infection, making AMR one of the foremost threats to human and animal health. Animal agriculture's large use of antibiotics in food animals is an important factor in AMR. As such, policies to reduce antibiotic use and combat AMR in animal agriculture in the United States (US) have been in place or are developed. One key to the success of these policies in the US is understanding how a major stakeholder - veterinarians treating dairy cattle - perceive the scale of antibiotic use, the threat of AMR and the utility of antibiotic use policies. We interviewed 9 dairy veterinarians in New York State and conducted an iterative thematic analysis of their responses, through which five themes were identified: 1. veterinarians' views of the frequency and reasons for antibiotic misuse, 2. their ideas on reducing antibiotic use, 3. perceptions of AMR within the dairy industry, 4. view of organic farming and how it relates to animal welfare, and 5. the impact of consumers' beliefs on the dairy industry. Participants viewed antibiotic overuse as largely due to farmers' concern for the welfare of their cattle and desire to treat ailments swiftly. Interviewees believed that it was possible to reduce antibiotic use through regulation, such as the Veterinary Feed Directive and improved herd management activities, such as better colostrum management, culture-based mastitis treatment, and improved housing conditions. They did not view the dairy industry as a significant contributor to AMR, particularly when compared to the human medical industry. Interviewees also offered their (unsolicited) opinion on organic dairy farming in the US and expressed frustration with the limited treatment options available in organic dairy farming and how this dynamic may potentially compromise animal welfare. Finally, they commented on the impact of consumers' beliefs on the dairy industry, expressing frustration with how misinformation about the dairy industry has led to consumer driven changes. As consumer beliefs have an impact on the dairy industry, this influence could be leveraged to further decrease antibiotic use. These findings can help guide future efforts in veterinarian-client communication and the development and implementation of effective policies in New York State. These results also highlight the need for more quantitative research on antibiotic use in the dairy industry, as without this data it will be difficult to ascertain the true impact of policy interventions.

How does public perception of antibiotic use on dairy farms contribute to self-reported purchasing of organic?

The United States regulates the use of antibiotics in agricultural settings to address the global antibiotic resistance problem. Conventional dairy cows treated with antibiotics are kept in the herd and after the withholding period milk is harvested. On organic farms, the US organic standard on antibiotic use requires sick dairy cows to be treated, but treated cows must be removed from the herd and their milk can never again be sold as certified organic. This study investigated the US public's perceptions of the organic dairy farming, antibiotic use on dairy farms, and whether these perceptions affect consumer's self-reported purchasing behavior for organic. We used a nationally representative phone-based survey of 1000 US adults and characterized participants' self-reported (i) knowledge of the legality of antibiotic use on dairy farms (conventional and organic) and (ii) frequency of purchasing organic instead of conventional dairy products, as well as several demographic and other variables. The results indicated that participants' knowledge about antibiotic use practices in dairy farming have no effect on their self-reported purchasing behavior for organic or conventional dairy products. However, respondents who were familiar with the regulations of antibiotic use on dairy farms were more likely to oppose the US organic standard on antibiotic use in dairy farming and thought that past antibiotic use should not permanently remove a cow's organic status. These findings contribute to understanding of public perceptions that shape the US dairy organic market. PRACTICAL APPLICATION: Income, employment, health and political values, but not consumers' knowledge about antibiotic use in dairy farming, affect self-reported purchasing behavior for organic dairy products. However, consumers who are familiar with the regulations of antibiotic use on US dairy farms disagree with the US organic standard on antibiotic use mandating loss of organic status for any cattle treated with antibiotics. These findings may be useful to organic markets.

Survey of perceptions and attitudes of an international group of veterinarians regarding antibiotic use and resistance on dairy cattle farms.

Veterinarians are the main source of information for farmers regarding the responsible use of antibiotics in farm animals and how to reduce the risk of antibiotic resistance. Consequently, understanding how veterinarians perceive their clients' and colleagues' antibiotic use and their own beliefs about the development of antibiotic resistance is essential to determining areas in which antibiotic use practices can be improved to minimize the emergence of antibiotic resistance. An international cross-sectional study was carried out using a questionnaire designed to elucidate perceptions, attitudes, and concerns of dairy veterinarians regarding antibiotic use and the emergence of antibiotic resistance in dairy farming. The questionnaire was initially administered to veterinarians attending the International Bovine Mastitis Conference in Milano, Italy, 2018, followed by veterinarian members of the National Mastitis Council, and all conference registrants. A total of 71 participants from 21 countries participated in the survey, the majority were from the United States and member countries of the European Union. Logistic regression analysis was conducted to identify predictors of veterinarians' level of concern about the development of antibiotic resistance on their clients' farms. Associations were described with odds ratios (ORs) and the associated 95 % confidence intervals (95 % CIs). Free text responses where participants shared their views on the reason for overprescribing antibiotics by veterinarians were analyzed using thematic analysis. Participants perceived that nearly half of their clients overuse or inappropriately use antibiotics, and nearly half of their colleagues overprescribe or inappropriately prescribe antibiotics. After controlling for other factors, the odds of veterinarians being concerned about antibiotic resistance on dairy farms they served decreased by a factor of 0.91 for each additional year of participants' experience working with dairy cattle (OR = 0.91, 95 % CI = 0.84-0.99). Participants concerned about antibiotic resistance on clients' dairy farms were also more likely to consider better adherence to drug labelling as important for reducing farmers' antibiotic use (OR = 6.86, 95 % CI = 1.21-38.93). Thematic analysis revealed four themes surrounding the perceived reasons for veterinarians' overprescribing of antibiotics: (i) knowledge, (ii) attitudes, (iii) barriers, and (iv) rules and regulations. The study findings will aid in the development of strategies to improve antibiotic use in dairy farming and educational initiatives looking to enhance the communication between veterinarians and farmers about judicious use of antibiotics.

Phase Measurements of a 140-GHz Confocal Gyro-Amplifier.

The phase stability of a 140GHz, 1kW pulsed gyro-amplifier system and the phase dependence on the cathode voltage were experimentally measured. To optimize the measurement precision, the amplifier was operated at 47 kV and 1 A, where the output power was ∼ 30W. The phase was determined to be stable both pulse-to-pulse and during each pulse, so far as the cathode voltage and electron beam current are constant. The phase variation with voltage was measured and found to be 130±30°/kV, in excellent agreement with simulations. The electron gun used in this device is non-adiabatic, resulting in a steep slope of the beam pitch factor with respect to cathode voltage. This was discovered to be the dominant factor in the phase dependence on voltage. The use of an adiabatic electron gun is predicted to yield a significantly smaller phase sensitivity to voltage, and thus a more phase-stable performance. To our knowledge, these are the first phase measurements reported for a gyro-amplifier operating at a frequency above W-band.

Second Harmonic 527-GHz Gyrotron for DNP-NMR: Design and Experimental Results.

We report the design and experimental demonstration of a frequency tunable terahertz gyrotron at 527 GHz built for an 800 MHz Dynamic Nuclear Polarization enhanced Nuclear Magnetic Resonance (DNP-NMR) spectrometer. The gyrotron is designed at the second harmonic (ω = 2ω c) of the electron cyclotron frequency. It produces up to 9.3 W continuous microwave (CW) power at 527.2 GHz frequency using a diode type electron gun operating at V = 16.65 kV, Ib = 110 mA in a TE11,2,1 mode, corresponding to an efficiency of ~0.5%. The gyrotron is tunable within ~ 0.4 GHz by combining voltage and magnetic field tuning. The gyrotron has an internal mode converter that produces a Gaussian-like beam that couples to the HE11 mode of an internal 12 mm i.d. corrugated waveguide periscope assembly leading up to the output window. An external corrugated waveguide transmission line system is built including a corrugated taper from 12 mm to 16 mm i.d. waveguide followed by 3 m of the 16 mm i.d. waveguide The microwave beam profile is measured using a pyroelectric camera showing ~ 84% HE11 mode content.

Effects of Egocentric Projection and Identification on Narrative Persuasion in Foodborne Illness Messages.

This study conceptually and empirically distinguishes two mental processes in narrative processing of food safety health messages-identification with and egocentric projection onto story characters. Two studies examined the effects of narrative autobiographical accounts of contracting foodborne illness (salmonella) because of careless food preparation. Both studies consistently found that identification increased, but egocentric projection decreased audience members' behavioral intention to perform safe food handling practices, indicating that egocentric projection and identification represent unique mental processes and yield distinct persuasive outcomes. In addition, confirmatory factor analyses provided evidence that egocentric projection and identification are distinct constructs. Implications for the role of identification and egocentric projection for understanding narrative processing and for health persuasion are discussed.

Generation of High-Power, Reversed-Cherenkov Wakefield Radiation in a Metamaterial Structure.

We present the first demonstration of high-power, reversed-Cherenkov wakefield radiation by electron bunches passing through a metamaterial structure. The structure supports a fundamental transverse magnetic mode with a negative group velocity leading to reversed-Cherenkov radiation, which was clearly verified in the experiments. Single 45 nC electron bunches of 65 MeV traversing the structure generated up to 25 MW in 2 ns pulses at 11.4 GHz, in excellent agreement with theory. Two bunches of 85 nC with appropriate temporal spacing generated up to 80 MW by coherent wakefield superposition, the highest rf power that metamaterial structures ever experienced without damage. These results demonstrate the unique features of metamaterial structures that are very attractive for future high-gradient wakefield accelerators, including two-beam and collinear accelerators. Advantages include the high shunt impedance for high-power generation and high-gradient acceleration, the simple and rugged structure, and a large parameter space for optimization.

Laser-driven semiconductor switch for generating nanosecond pulses from a megawatt gyrotron.

A laser-driven semiconductor switch (LDSS) employing silicon (Si) and gallium arsenide (GaAs) wafers has been used to produce nanosecond-scale pulses from a 3 µs, 110 GHz gyrotron at the megawatt power level. Photoconductivity was induced in the wafers using a 532 nm laser, which produced 6 ns, 230 mJ pulses. Irradiation of a single Si wafer by the laser produced 110 GHz RF pulses with a 9 ns width and >70% reflectance. Under the same conditions, a single GaAs wafer yielded 24 ns 110 GHz RF pulses with >78% reflectance. For both semiconductor materials, a higher value of reflectance was observed with increasing 110 GHz beam intensity. Using two active wafers, pulses of variable length down to 3 ns duration were created. The switch was tested at incident 110 GHz RF power levels up to 600 kW. A 1-D model is presented that agrees well with the experimentally observed temporal pulse shapes obtained with a single Si wafer. The LDSS has many potential uses in high power millimeter-wave research, including testing of high-gradient accelerator structures.

Photonic-band-gap gyrotron amplifier with picosecond pulses.

We report the amplification of 250 GHz pulses as short as 260 ps without observation of pulse broadening using a photonic-band-gap circuit gyrotron traveling-wave-amplifier. The gyrotron amplifier operates with a device gain of 38 dB and an instantaneous bandwidth of 8 GHz. The operational bandwidth of the amplifier can be tuned over 16 GHz by adjusting the operating voltage of the electron beam and the magnetic field. The amplifier uses a 30 cm long photonic-band-gap interaction circuit to confine the desired TE03-like operating mode while suppressing lower order modes which can result in undesired oscillations. The circuit gain is >55 dB for a beam voltage of 23 kV and a current of 700 mA. These results demonstrate the wide bandwidths and a high gain achievable with gyrotron amplifiers. The amplification of picosecond pulses of variable lengths, 260-800 ps, shows good agreement with the theory using the coupled dispersion relation and the gain-spectrum of the amplifier as measured with quasi-CW input pulses.

Operation of a 140 GHz Gyro-amplifier using a Dielectric-loaded, Sever-less Confocal Waveguide.

The design and experimental results of a 140 GHz gyro-amplifier that uses a dielectric-loaded, sever-less confocal waveguide are presented. The gyro-traveling wave amplifier uses the HE06 mode of a confocal geometry with power coupled in and out of the structure with Vlasov-type, quasi-optical couplers. Dielectric loading attached to the side of the confocal structure suppresses unwanted modes allowing zero-drive stable operation at 48 kV and 3A of beam current. The confocal gyro-amplifier demonstrated a peak circuit gain of 35 dB, a bandwidth of 1.2 GHz and a peak output power of 550 W at 140.0 GHz.

Theory of Linear and Nonlinear Gain in a Gyroamplifier using a Confocal Waveguide.

The linear and nonlinear theory of a gyroamplifier using a confocal waveguide is presented. A quasi-optical approach to describing the modes of a confocal waveguide is derived. Both the equations of motion and the mode excitation equation are derived in detail. The confocal waveguide circuit has the advantage of reducing mode competition but the lack of azimuthal symmetry presents challenges in calculating the gain. In the linear regime, the gain calculated using the exact form factor for the confocal waveguide agrees with an azimuthally averaged form factor. A beamlet code including velocity spread effects has been written to calculate the linear and nonlinear (saturated) gain. It has been successfully benchmarked against the MAGY code for azimuthally symmetric cases. For the confocal waveguide, the beamlet code shows that the saturated gain is reduced when compared with results obtained using an azimuthally averaged form factor. The beamlet code derived here extends the capabilities of nonlinear gyroamplifier theory to configurations that lack azimuthal symmetry.

Transgender Youth in the Inpatient Psychiatric Setting: A Literature Review and Case Report.

Once considered pathological, transgenderism is now accepted as a variant of normal sexuality. As society has become more accepting of transgenderism, increasing numbers of transgender patients have begun to seek psychiatric care, and younger populations are embracing their gender differences. There is a paucity of literature on how best to serve transgender youth in psychiatric inpatient units. In this article, we share our experience and discuss the need for practical guidelines to help the inpatient psychiatrist navigate key topics related to this population. We then present a case report to illustrate several of these issues. A major goal of this report is to increase the literature base.