Dirty Contacts Research Articles

Potential food safety risks in tomato value chains in urban settings of Eastern Ethiopia: a qualitative investigation

BackgroundThe value chains of tomatoes in Ethiopia are largely informal which may pose potential food safety risks. Value chains (VCs) mapping was carried out with emphasis on tomatoes in two major cities in eastern Ethiopia—Harar and Dire Dawa—which were assessed to identify practices likely to result in unsafe food, considering production, transportation, retail, preparation, and consumption.MethodsQualitative methods were used to map the VCs to understand the flows, actors, and practices. Group discussions and key informant interviews were performed to better understand the processes, practices, beliefs, and food safety risks in these VCs.ResultsThe two cities are supplied by two vegetable VCs: the first and larger being from distant producers in central Ethiopia, and the second from surrounding rural and peri-urban producers. The long-distance VCs involve producers, brokers, transporters, wholesalers, retailers, and consumers. The local producers, however, bring their fresh products directly to the cities without the involvement of VC actors other than final retailers and consumers. The study suggests microbiological contamination risks along tomato VCs, potentially including soil contamination, use of sewerage-contaminated irrigation water, untreated manure, unhygienic handling and storage conditions, and dirty contact surfaces during transportation and retailing. Tomatoes are mostly harvested by hand picking, collected, and sorted on the ground exposing to sunlight and physical bruising with potential contamination. More importantly, tomatoes are widely consumed raw without “a kill-step” that certainly contributes to food-borne infections. Suggestions by study participants for improving food safety and hygiene include funding toward improved infrastructure and facilities in the sectors, supporting VC actors with improved technology for quality production, and increasing awareness of good and hygienic practices. Consumers were particularly concerned about contamination with agrochemicals without much emphasis on the potential microbial contaminants. Fresh tomatoes are prepared in a variety of ways and are often consumed raw or slightly cooked. Further recommendations included using health extension workers to conduct awareness campaigns on improved food safety and hygienic practices.ConclusionThe qualitative VC mapping generated useful information for designing intervention strategies, especially targeting developing food safety interventions and an awareness communication campaign.

Difficulty Using Smart Pump Logs to Recreate a Patient Safety Event: Case Study and Considerations for Pump Enhancements

The authors present a case in which a physical anomaly with an infusion pump resulted in an unforeseen fault that the nurse’s attempts to resolve unknowingly exacerbated. This case study presents the first report in the literature to detail the difficulty in recreating a patient safety event using smart pump logs, support server continuous quality improvement (CQI) data, and the drug order entry system to elucidate the clinical scenario. A 75-year-old male patient presented to a major teaching hospital and was admitted to the intensive care unit (ICU) with a massive gastrointestinal bleed and myocardial infarction, then stabilized. One of the patient’s pumps alarmed “communication error” on the display. The display gave no explicit instructions about how to resolve the issue, and resolution was not intuitive. Attempts to clear the alarm failed, so the module was disconnected to reprogram the infusion, causing an interruption in the dopamine. Over the course of approximately 2 min of troubleshooting, the patient’s blood pressure decreased from 109/50 to 60/30, with a rapid pulse change from a consistent 95 up to 115 and subsequently 135 beats per minute. A cardiac arrest ensued and a code blue was called. All cardiac drugs, including the dopamine, were suspended during the code. Cardiopulmonary resuscitation was performed and the patient survived the code. Post-code, the dopamine and epinephrine were restarted, and the norepinephrine was discontinued. The patient’s condition remained very unstable. Pump logs and the server database were queried to locate relevant equipment. It was concluded that dirty contacts on the inter-unit interface (IUI) connectors between the PC unit (PCU) and the modules caused the alarm message “communication error” to appear on the PCU display. Learning yielded a nursing practice alert to clarify how a nurse should resolve a “communication error”, and appropriate cleaning protocols were promptly implemented. The investigation found smart pump event logs and proprietary software are not designed with any forethought as to retrospective reconstruction of incident investigations, leaving facilities to cobble together pieces of information from multiple sources to determine what occurred. The authors also suggest further pump enhancements, challenging pump manufacturers to go to the next level of integration and enable greater patient safety with smart infusion pumps.

Hand Hygiene Practices among Nursing Staff in Public Secondary Care Hospitals in Kuwait: Self-Report and Direct Observation

Objective: To assess the compliance with hand hygiene guidelines among nursing staff in secondary care hospitals in Kuwait. Subjects and Methods: A cross-sectional study was conducted through direct observation using the Lewisham observation tool and self-administered questionnaire in six major public secondary care hospitals in Kuwait. Only patient care activities that are described as ‘dirty contacts’ by the Fulkerson scale were considered as indications for hand hygiene while any attempt for hand hygiene was considered as compliance. A self-administered questionnaire was prepared and pilot tested and then distributed to nursing staff at each ward immediately after conducting the inspection; 550 were distributed and 454 were completed and returned. Among 204 observation sessions, a total of 935 opportunities and 312 hand hygiene practices were recorded. Results: The overall compliance was 33.4%. The observed compliance significantly varied between different ward categories from 14.7% in emergency to 55% in medical wards. Of the 454 nursing staff who participated in self-reported compliance, 409 (90%) indicated that they always washed their hands upon practicing patient care activities. Nurses consistently reported higher compliance after conducting patient care activities rather than before. Being busy with work (42.2%), having sore/dry hands (30.4%) and wearing gloves (20.3%) were the most frequently reported hindrances to improving hand hygiene. Conclusion: Observed hand hygiene compliance among nursing staff in secondary care hospitals in Kuwait was poor. High self-reported compliance may reflect a high level of awareness of hand hygiene but may also suggest that improving compliance through increasing awareness has probably reached saturation.

Effect of temperature and bias voltage on the conductance distribution of 1D-disordered wires with dirty contacts

We compute the distribution of the conductance P ( G ( T , V ) ) of a one-dimensional (1D) disordered wire non-perfectly coupled to leads (dirty contacts) at finite temperature T and bias voltage V. At regimes of temperatures and/or bias voltages larger than the mean level spacing, we show that the conductance distribution can be accurately represented by a finite number of convolutions of the distribution p ( g c ) of the conductance g c at zero temperature and zero bias voltage.

Contact between Carbon Nanotube and Metallic Electrode

Effects of a contact between a carbon nanotube and metallic electrode are studied in a tight-binding model. A model of dirty contact is introduced and discussed for electrode weakly coupled to a carbon nanotube. Measurements of a perfect transmission in two-terminal measurement may be possible by the using of the contact with both weak coupling and large area.

Hand Washing Frequency in an Emergency Department

Study objective: Previous studies, conducted mainly in ICUs, have shown low compliance with hand-washing recommendations, with failure rates approaching 60%. Hand washing in the emergency department has not been studied. We examined the frequency and duration of hand washing in one ED and the effects of three variables: level of training, type of patient contact (clean, dirty, or gloved), and years of staff clinical experience. Design: Observational. Setting: ED of an 1,100-bed tertiary referral, central city, private teaching hospital. Participants: Emergency nurses, faculty, and resident physicians. Participants were informed that their activities were being monitored but were unaware of the exact nature of the study. Interventions: An observer recorded the number of patient contacts and activities for each participant during three-hour observation periods. Activities were categorized as either clean or dirty according to a scale devised by Fulkerson. The use of gloves was noted and hand-washing technique and duration were recorded. A hand-washing break in technique was defined as failure to wash hands after a patient contact and before proceeding to another patient or activity. Results: Eleven faculty, 11 resident physicians, and 13 emergency nurses were observed. Of 409 total contacts, 272 were clean, 46 were dirty, and 91 were gloved. Hand washing occurred after 32.3% of total contacts (SD, 2.31%). Nurses washed after 58.2% of 146 contacts (SD, 4.1%), residents after 18.6% of 129 contacts (SD, 3.4%), and faculty after 17.2% of 134 contacts (SD, 3.3%). Nurses had a significantly higher hand washing frequency than either faculty ( P < .0001) or resident physicians ( P < .0001). Hand washes occurred after 28.4% of 272 clean contacts (SD, 2.34%), which was significantly less ( P < .0001) than 50.0% of 46 dirty contacts (SD, 7.4%) and 64.8% of 91 gloved contacts (SD, 5.0%). The number of years of clinical experience was not significantly related to hand-washing frequency ( P = .82). Soap and water were used in 126 of the hand washes, and an alcohol preparation was used in the remaining six. The average duration of soap-and-water hand washes was 9.5 seconds. Conclusion: Compliance with hand washing recommendations was low in this ED. Nurses washed their hands significantly more often than either staff physicians or resident physicians, but the average hand-washing duration was less than recommended for all groups. Poor compliance in the ED may be due to the large number of patient contacts, simultaneous management of multiple patients, high illness acuity, and severe time constraints. Strategies for improving compliance with this fundamental method of infection control need to be explored because simple educational interventions have been unsuccessful in other health care settings. [Meengs MR, Giles BK, Chisholm CD, Cordell WH, Nelson DR: Hand-washing frequency in an emergency department. Ann Emerg Med June 1994;23:1307-1312.]

Mesoscopic transport beyond linear response.

We present an approach to steady-state mesoscopic transport based on the masimum entropy principle formulation of nonequilibrium statistical mechanics. Our approach is not limited to the linear response regime. This approach yields the quantization observed in the integer quantum Hall effect at large currents, which until now has been unexplained. We also predict new behaviors of nonlocal resistances at large currents in the presence of dirty contacts.

ANNULAR EFFECT AND OTHER PATTERNS OF CURRENT DISTRIBUTION IN POINT CONTACTS

The experiments with point-contacts, containing type-II superconductors, gave possibility to study the conditions with different current density distributions in contact cross-section. The current density is constant over the cross-section of pure contacts with the ballistic electron transport: d &lt; &lt; li, where d is the contact diameter, li is the impurity (elastic) mean free path of electrons. A uniform current flow also occurs in contacts between pure electrodes separated with a thin layer of a metal (t &lt; &lt; d) having high resistivity. In dirty contacts (d &gt; &gt; li) an annular effect is observed: the current density is low in the centre and the highest at the contact section periphery. The relative width of the annulus of the flowing current is proportional to li/d. In contacts between two type-II superconductors in the zero external magnetic field, the current first flows over an annulus, whose width increases with the current. In the critical state preceding the superconductivity destruction in the contact, the current density reaches its highest value in the center and decreases towards the periphery as r−1/2.

Anisotropy of electron-phonon interaction spectra in a magnetic field and quantum interference effects in antimony point contacts

Peculiarities of point-contact spectra behavior of antimony are investigated in a magnetic field. It turns out that the singularities in the spectra can both decrease and increase depending not only on orientation of the contact axes with respect to the crystallographic axis of Sb and the magnetic field vector, but also on the ratio between the contact diameter, the Larmour radius of the charge carriers and their mean free path. The spectrum sign inversion for a dirty contact that is due to electron state delocalization as a result of electronphonon interaction is detected. It means that point-contact spectroscopy is possible in highly disordered materials when the quantum localization is significant.

Sources of error in automated static perimetry

Several sources of errors in interpreting computerized visual fields (learning effect, miotic pupil, sub-optimal refraction, dirty contact lenses, inadequate patient cooperation, anatomical obstacle, and choice of the wrong program) are described with the help of examples. Their identification should result in more reliable diagnoses.

Phonon singularities on volt-ampere curves of niobium point contacts

The volt-ampere curves and their second derivatives were studied for niobium point contacts at low temperatures in the voltage range corresponding to the characteristic phonon energies. It was found that while for the dirty contacts in the normal state no PC spectra of phonons could be detected, in the superconducting state there were singularities in the I– V curves corresponding to maxima either in the first or in the second derivatives. The singularities observed were due to the energy dependence of the excess current. We suppose that the origin of these singularities is due to the inelastic transitions of electrons between chemical potentials of Cooper pairs at both sides of the contact, which differ in energy by eV. These transitions are possible if ξ(0) ⪞ d ≈ Λ ϵ, (ξ(0) being the coherence length; d, the contact diameter; Λ ϵ = (l i·l ϵ) 1 2 , where l i and l ϵ being the elastic and inelastic electron mean free paths, respectively).

Some properties of dirty contacts on semiconductors and resistivity measurements by a two-terminal method : G. G. Harman and T. Higier, J. Appl. Phys.33, No. 7, 2198–2206 (1962)

Some properties of dirty contacts on semiconductors and resistivity measurements by a two-terminal method : G. G. Harman and T. Higier, J. Appl. Phys.33, No. 7, 2198–2206 (1962)

Some Properties of Dirty Contacts on Semiconductors and Resistivity Measurements by a Two-Terminal Method

The surface and bulk properties of semiconductors have been studied by a two-terminal method using dirty contacts. These contacts are defined as ones that are easily applied and removed and that are separated from the bulk by surface states, oxides, adhered gasses, and chemical films. The method essentially involves measuring the resistance-voltage (R-V) characteristics from the millivolt range up to about 100 V, and from these data the sample resistivity can be obtained directly. The effect of work damaging or etching the semiconductor surface can be readily evaluated. By observation of the shape of the R-V curves it is possible to separate the bulk from the surface effects, calculate the surface barrier height and thickness from tunneling equations, and determine whether the barrier is a surface film or due to metal-semiconductor contact potential difference. An application of the theory of electric field tunneling of Holm to the data of silicon carbide gives values of about 2.4 eV for the barrier height and 13 Å for the barrier width of the film on the surface. Sufficient information is included on electrode techniques and pitfalls so that the experimentalist can readily make the measurements. Efforts were concentrated on silicon carbide and silicon, but the techniques are applicable to all types of semiconductors.

Studies from the Autotrephon, I. Some Points in General Operation and Maintenance

The Autotrephon, described in Stanley, 1951, though very carefully designed, is somewhat complicated, and the experience of two years has shown that there are some points with respect to its operation and maintenance which should be placed on record. Warm-chamber controls. The setting of the thermostat for the humidifier heater (Stanley 1951, TH-3, Fig. 11) is very important. If it does not cut in and out within about 0..10 C., of the warm-chamber temperature, quite pronounced surges will occur in the temperature of that chamber. These will show as rather regularly spaced spikes or peaks on the temperature record. Under dry room conditions, where humidification is frequent, these spikes may run together to form a saw-tooth record. Dirty contacts on the warm-chamber thermostat (ibid., TH-1, Fig. 3) produce a very irregular variation in the temperature record. When the heater of the warm chamber (ibid., H, Fig. 3) operates, it causes a small rise of temperature (about 0.30 C.) in the air flowing down the lateral airchannels of the warm chamber. As the wet-bulb thermometer is set in this stream (ibid., WBT, Fig. 3), readings should not be taken when the heater is operating. A neon pilot light should be wired in parallel with the heater to act as an indicator. When running with the warm-chamber temperature very close to that of the surrounding room, it will be found that the chamber tends to control on the cooling system during the day, and on the heater at night. This produces a reiterated step effect on the record. This cannot be eliminated, but it can be minimized by making the differential on TH-1 as small as possible. The differential should be reduced to the point where the cooling system just fails to operate from the minute overshoot of the heating system. This will give a differential of perhaps 0.15 to 0.20 C. The differential of the humidistat (Ibid., Fig. 5) should not be set too fine, as the contact arm (ibid., CA, Fig. 12) naturally has a rather large swing. Experience is the only guide, but the total gap between the contact arm and the fixed contacts can be about 1/32 in. If the apparatus is shut down, the tension on the hairstrand should be released by turning the adjusting nut AN (ibid., Fig. 12) until the strand is limp. If this is not done, the hairs may break on a dry day. To prevent the hair-strand twisting when the adjusting nut is turned, a small cross-pin should be put through the rod R (ibid., Fig. 12). This should be located just where the end of the dotted pointer touches the rod, R, in Figure 12. It can be installed by sweating a brass sleeve (1/16 O.D.) over R, and drilling through this assembly, and sweating in a 34-in. length of piano wire. If this wire is held between finger and thumb of the left hand while AN is turned with the right, adjustments are readily made. The end-clips of the hair-strand were not clearly shown in Stanley 1951, and one is therefore shown herewith as Figures 1A and 1B. The clip should be milled out of non-thermoplastic bakelite, and cannot be re-used. The hairs are ordinarily human hair. We have not found that blond hairs are essential. The hairs need only be washed with ether prior to use, to wash off grease. Any good grade celluloid cement will do for cementing the hairs into the clip, but it is important that they be stretched evenly before cementing. This may be done by cementing into one clip, threading through the holes of the second clip, and hanging