487 research outputs found
Wind Field and Trajectory Models for Tornado-Propelled Objects
A mathematical model to predict the trajectory of tornado born objects postulated to be in the vicinity of nuclear power plants is developed. An improved tornado wind field model satisfied the no slip ground boundary condition of fluid mechanics and includes the functional dependence of eddy viscosity with altitude. Subscale wind tunnel data are obtained for all of the missiles currently specified for nuclear plant design. Confirmatory full-scale data are obtained for a 12 inch pipe and automobile. The original six degree of freedom trajectory model is modified to include the improved wind field and increased capability as to body shapes and inertial characteristics that can be handled. The improved trajectory model is used to calculate maximum credible speeds, which for all of the heavy missiles are considerably less than those currently specified for design. Equivalent coefficients for use in three degree of freedom models are developed and the sensitivity of range and speed to various trajectory parameters for the 12 inch diameter pipe are examined
An Investigation of a Supersonic Aircraft Configuration Having a Tapered Wing with Circular-arc Sections and 40 Degree Sweepback : Force Characteristics of the Complete Configuration and Its Various Components at Mach Numbers of 1.40 and 1.59
A new distribution record and a previously undocumented color pattern of the Hispaniolan Yellow Tree Frog, Osteopilus pulchrilineatus (Hylidae), in the Dominican Republic
A guide to the establishment and maintenance of milkfish broodstock
The manual describes methods used at the SEAFDEC Aquaculture Department in order to establish milkfish broodstock. It is presented under the following major section headings: Establishing broodstock farms; Farms for rearing bangus juveniles; Maturation cages for rearing broodstock to maturity; Gathering data; Spawning and egg collection; and Larval rearing.This study as well as the publication of this guide was partly supported by the International Development Research Centre of Canada under Project No. 3-P78-0033 (Phase II) and No. 3-P81-0171 (Phase III)
Laparoscopic approach to Meckel's diverticulum
Aim.To retrospective review the laparoscopic management of Meckel Diverticulum (MD) in two Italian Pediatric Surgery Centers.
METHODS:
Between January 2002 and December 2012, 19 trans-umbilical laparoscopic-assisted (TULA) procedures were performed for suspected MD. The children were hospitalized for gastrointestinal bleeding and/or recurrent abdominal pain. Median age at diagnosis was 5.4 years (range 6 mo-15 years). The study included 15 boys and 4 girls. All patients underwent clinical examination, routine laboratory tests, abdominal ultrasound and technetium-99m pertechnetate scan, and patients with bleeding underwent gastrointestinal endoscopy. The abdominal exploration was performed with a 10 mm operative laparoscope. Pneumoperitoneum was established based on the body weight. Systematic overview of the peritoneal cavity allowed the ileum to be grasped with an atraumatic instrument. The complete exploration and surgical treatment of MD were performed extracorporeally, after intestinal exteriorization through the umbilicus. All patients' demographics, main clinical features, diagnostic investigations, operative time, histopathology reports, conversion rate, hospital stay and complications were registered and analyzed.
RESULTS:
MD was identified in 17 patients, while 1 had an ileal duplication and 1 a jejunal hemangioma. Fifteen patients had painless intestinal bleeding, while 4 had recurrent abdominal pain and exhibited cyst like structures in an ultrasound study. Eleven patients had a positive technetium-99m pertechnetate scan. In the patients with bleeding, gastrointestinal endoscopy did not name the source of hemorrhage. All patients were subjected to a TULA surgical procedure. An intestinal resection/anastomosis was performed in 14 patients, while 4 had a wedge resection of the diverticulum and 1 underwent stapling diverticulectomy. All surgical procedures were performed without conversion to open laparotomy. Mean operative time was 75 min (range 40-115 min). No major surgical complications were recorded. The median hospital stay was 5-7 d (range 4-13 d). All patients are asymptomatic at a median follow up of 4, 5 years (range 10 mo-10 years).
CONCLUSION:
Trans-umbilical laparoscopic-assisted Meckel's diverticulectomy is safe and effective in the treatment of MD, with excellent results.
KEYWORDS:
Gastrointestinal bleeding; Ileal duplication; Jejunal hemangioma; Laparoscopy; Meckel’s diverticulum; Minimal invasive surgery; One trocar surger
REST/NRSF drives homeostatic plasticity of inhibitory synapses in a target-dependent fashion
The repressor-element 1-silencing transcription/neuron-restrictive silencer factor (REST/NRSF) controls hundreds of neuron-specific genes. We showed that REST/NRSF downregulates glutamatergic transmission in response to hyperactivity, thus contributing to neuronal homeostasis. However, whether GABAergic transmission is also implicated in the homeostatic action of REST/NRSF is unknown. Here, we show that hyperactivity-induced REST/NRSF activation, triggers a homeostatic rearrangement of GABAergic inhibition, with increased frequency of miniature inhibitory postsynaptic currents (IPSCs) and amplitude of evoked IPSCs in mouse cultured hippocampal neurons. Notably, this effect is limited to inhibitory-onto-excitatory neuron synapses, whose density increases at somatic level and decreases in dendritic regions, demonstrating a complex target- and area-selectivity. The upscaling of perisomatic inhibition was occluded by TrkB receptor inhibition and resulted from a coordinated and sequential activation of the Npas4 and Bdnf gene programs. On the opposite, the downscaling of dendritic inhibition was REST-dependent, but BDNF-independent. The findings highlight the central role of REST/NRSF in the complex transcriptional responses aimed at rescuing physiological levels of network activity in front of the ever-changing environment
Cross-cultural adaption and psychometric investigation of the German version of the Evidence Based Practice Attitude Scale (EBPAS-36D)
Background: The implementation of evidence-based practice (EBP) in mental health care confers many benefits to patients, and research into factors facilitating the implementation of EBP is needed. As an important factor affecting the implementation of EBP, service providers’ attitudes toward EBP emerged. The Evidence-Based Practice Attitude Scale (EBPAS-36) is an instrument with good psychometric characteristics that measures positive and ambivalent attitudes toward EBP. However, a German version is missing. The present study therefore aims to provide a validated German translation of the EBPAS-36.
Methods: The scale was translated and back-translated as recommended by standard procedures. German psychotherapists were recruited to participate in an online survey. They provided demographic and professional information, completed the EBPAS-36, the Implementation Climate Scale (ICS) and the Intention Scale for Providers (ISP). Standard item and reliability analyses were conducted. Construct validity was evaluated with exploratory (EFA) and confirmatory factor analyses (CFA) in two subsamples (random split). Convergent validity was tested by predicting a high positive correlation of the EBPAS-36D with two scores of attitudes of the ISP and an interest in EBP score. It was tested whether the EBPAS-36D predicts the intention to use EBP.
Results: N = 599 psychotherapists participated in the study. The item analyses showed a mean item difficulty of pi = 0.64, a mean inter-item correlation of r = 0.18, and a mean item-total correlation of ritc = 0.40. The internal consistency was very good for the total scale (α = 0.89) and ranged from adequate to very good for the subscales (0.65–0.89), indicating high reliability. The original factor structure showed an acceptable model fit (RMSEA = 0.064 (90% CI = 0.059–0.068); SRMR = 0.0922; AIC = 1400.77), confirming the 12-factor structure of the EBPAS-36. However, a second-order factor structure derived by the EFA had an even better model fit (RMSEA = 0.057 (90% CI = 0.052–0.062); SRMR = 0.0822; AIC = 1274.56). When the EBPAS-36D was entered in a hierarchical regression model with the criterion Intention to use EBP, the EBPAS-36D contributed significantly to the prediction (Change in R2 = 0.28, p < 0.001) over and above gender, age and participants’ report of ever having worked in a university context.
Conclusions: The present study confirms good psychometric properties and validity of a German version of the EBPAS-36 in a sample of psychotherapists
Wave Packet Echoes in the Motion of Trapped Atoms
We experimentally demonstrate and systematically study the stimulated revival
(echo) of motional wave packet oscillations. For this purpose, we prepare wave
packets in an optical lattice by non-adiabatically shifting the potential and
stimulate their reoccurence by a second shift after a variable time delay. This
technique, analogous to spin echoes, enables one even in the presence of strong
dephasing to determine the coherence time of the wave packets. We find that for
strongly bound atoms it is comparable to the cooling time and much longer than
the inverse of the photon scattering rate
Pelviureteral junction obstruction: correlation of renal cell apoptosis and differential renal function
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