WindSat radio-frequency interference signature and its identification over land and ocean

Radio-frequency interference (RFI) in the spaceborne multichannel radiometer data of WindSat and the Advanced Microwave Scanning Radiometer-EOS is currently being detected using a spectral difference technique. Such a technique does not explicitly utilize multichannel correlations of radiometer data, which are key information in separating RFI from natural radiations. Furthermore, it is not optimal for radiometer data observed over ocean regions due to the inherent large natural variability of spectral difference over ocean. In this paper, we first analyzed multivariate WindSat and Scanning Multichannel Microwave Radiometer (SMMR) data in terms of channel correlation, information content, and principal components of WindSat and SMMR data. Then two methods based on channel correlation were developed for RFI detection over land and ocean. Over land, we extended the spectral difference technique using principal component analysis (PCA) of RFI indices, which integrates statistics of target emission/scattering characteristics (through RFI indices) and multivariate correlation of radiometer data into a single statistical framework of PCA. Over ocean, channel regression of X-band can account for nearly all of the natural variations in the WindSat data. Therefore, we use a channel regression-based model difference technique to directly predict RFI-free brightness temperature, and therefore RFI intensity. Although model difference technique is most desirable, it is more difficult to apply over land due to heterogeneity of land surfaces. Both methods improve our knowledge of RFI signatures in terms of channel correlations and explore potential RFI mitigation, and thus provide risk reductions for future satellite passive microwave missions such as the NPOESS Conical Scanning Microwave Imager/Sounder. The new RFI algorithms are effective in detecting RFI in the C- and X-band Windsat radiometer channels over land and ocean.     

Visual search in complex displays: factors affecting conflict detection by air traffic controllers

Recent free flight proposals to relax airspace constraints and give greater autonomy to aircraft have raised concerns about their impact on controller performance. Relaxing route and altitude restrictions would reduce the regularity of traffic through individual sectors, possibly impairing controller situation awareness. We examined the impact of this reduced regularity in four visual search experiments that tested controllers' detection of traffic conflicts in the four conditions created by factorial manipulation of fixed routes (present vs. absent) and altitude restrictions (present vs. absent). These four conditions were tested under varying levels of traffic load and conflict geometry (conflict time and conflict angle). Traffic load and conflict geometry showed strong and consistent effects in all experiments. Color coding altitude also substantially improved detection times. In contrast, removing altitude restrictions had only a small negative impact, and removing route restrictions had virtually no negative impact. In some cases conflict detection was actually better without fixed routes. The implications and limitations of these results for the feasibility of free flight are discussed. Actual or potential applications include providing guidance in the selection of free flight operational concepts.     

Collateral blood supply through the ophthalmic artery: a steal phenomenon analyzed by color Doppler imaging

OBJECTIVE: This study aimed to evaluate the retrobulbar circulatory effects of reversed ophthalmic artery flow (ROAF) on the ophthalmic artery branches by means of color Doppler imaging. DESIGN: The design was a case-controlled study. PARTICIPANTS: Among 56 consecutive patients with severe (>70% stenosis) occlusive carotid artery disease, 15 patients (26.8%) with ROAF were identified. The control group consisted of 15 patients with similar degrees of carotid artery stenosis and forward ophthalmic artery flow. INTERVENTION: Arteriography and measurement of the retrobulbar hemodynamic parameters with color Doppler imaging were performed. MAIN OUTCOME MEASURES: Blood flow velocities and resistive index in the ophthalmic, central retinal, and temporal short posterior ciliary arteries were measured. RESULTS: Arteriography confirmed the diagnosis of ROAF in all 15 patients. There was no patient with ROAF diagnosed by arteriography and not diagnosed by color Doppler imaging. The frequency of bilateral severe occlusive carotid artery disease was significantly higher in the ROAF group (40%) compared to the control group (6.6%) (P = 0.04). Patients with ROAF showed significantly reduced vascular resistance in the ophthalmic artery (P = 0.03), higher vascular resistance, and lower blood flow velocities in the central retinal and temporal short posterior ciliary arteries (P < 0.05). CONCLUSION: This study suggests that patients with ROAF show a steal phenomenon, characterized by a shunt to the low-resistance intracranial circuit and reduction of retrobulbar blood flow.     

The role of human papillomavirus DNAs in cervical carcinoma and risk of lymph node metastasis: association with 72-kilodalton metalloproteinase immunostaining

BACKGROUND: The role of human papillomavirus (HPV) as a prognostic factor in cervical carcinoma is not understood completely and little is known regarding the intrinsic mechanisms involved in the metastatic process of HPV positive carcinoma. The authors evaluated HPV status with respect to clinical features in early stage cervical carcinoma, with special emphasis on lymph node spread. The authors also analyzed the relation between HPV, lymph node involvement, and 72-kilodalton (kDa) metalloproteinase immunostaining, an enzyme that cleaves Type IV collagen and may play a role in tumor metastasis. METHODS: Thirty-two patients with International Federation of Gynecology and Obstetrics Stage I and IIA squamous cell cervical carcinoma treated by primary radical surgery were reviewed. Histologic grade of differentiation, tumor size, fractional depth of invasion, and lymph node spread were evaluated with respect to HPV status and 72-kDa metalloproteinase immunostaining. HPV DNA was detected by polymerase chain reaction and the primers potentially recognized at least the following HPV subtypes: 6, 11, 16, 18, 31, 33, 34, 35, 42, 51, 56, and 58. Immunohistochemical staining was performed using the avidin-biotin complex technique. Affinity-purified rabbit anti-72-kDa metalloproteinase antibody was used. RESULTS: HPV DNA was detected in a total of 69% of cases, and HPV-16 was the most frequent type detected. HPV positive carcinomas showed a significantly higher rate of lymph node metastases than HPV negative carcinomas (45% vs. 10%; P = 0.03); similarly, 72-kDa metalloproteinase index was significantly higher (P = 0.001). CONCLUSIONS: These findings suggest a relation between HPV and risk of lymph node metastasis, which may be mediated by an increased production of 72-kDa metalloproteinase.     

Transport and turnover of microtubules in frog neurons depend on the pattern of axonal growth

Empirical analysis of the profitability of moderate grazing are presented based on sample dairy farms in Pennsylvania and New York. Net income per cow was higher for dairy farms that employed moderate intensive grazing than for dairy farms that employed extensive grazing. Income appeared to be adequate for family living expenses, but moderate intensive grazing could not be considered a high profit system. Detailed analyses of dairy farms that employed moderate and extensive grazing in northern Pennsylvania indicated that returns to management and owner equity were higher for pasture enterprises than for corn silage or hay enterprises. Positive dairy profits were related to lower feed costs. Milk production was lower on farms that employed moderate grazing than on farms that employed extensive grazing. Logit regression analysis characterized farms that employed moderate intensive grazing as oriented toward dairy rather than toward crop production; these farms had lower culling rates and a greater dependence on milk sales as a share of total sales. The reduced use of fertilizers and chemicals suggests that moderate grazing had environmentally sustainable features.     

Agricultural use of antibiotics and the evolution and transfer of antibiotic-resistant bacteria

Microbial Resistance to antibiotics is on the rise, in part because of inappropriate use of antibiotics in human medicine but also because of practices in the agricultural industry. Intensive animal production involves giving livestock animals large quantities of antibiotics to promote growth and prevent infection. These uses promote the selection of antibiotic resistance in bacterial populations. The resistant bacteria from agricultural environments may be transmitted to humans, in whom they cause disease that cannot be treated by conventional antibiotics. The author reviews trends in antibiotic use in animal husbandry and agriculture in general. The development of resistance is described, along with the genetic mechanisms that create resistance and facilitate its spread among bacterial species. Particular aspects of resistance in bacterial species common to both the human population and the agrifood industry are emphasized. Control measures that might reverse the current trends are highlighted.     

Laparoscopic esophagomyotomy and antireflux procedure with intraoperative manometry

We have been routinely performing laparoscopic cholecystectomy and antireflux procedures. Having this experience, we decided to assess the feasibility and safety of performing a laparoscopic esophagomyotomy and antireflux procedure. Here we present a case of a 37-year-old man with a history of progressive dysphagia and a diagnosis of achalasia, made on the basis of clinical, endoscopic, and manometric studies. Preoperative manometry reported a pressure of 52 mm Hg (normal, 15-25 mm Hg) for 4.5 cm (normal, > 3 cm). Laparoscopic esophagomyotomy and anterior fundoplication were performed. The esophagomyotomy included a 6-cm segment of distal esophagus and 2 cm of stomach; postoperative manometry was 18 mm Hg for 3 cm. Eight months postoperatively, a barium swallow demonstrated no reflux. Laparoscopic esophagomyotomy and antireflux procedure can be performed with efficacy and safety, with the advantage of a shorter hospitalization and an early recovery compared with the traditional procedure. Also, we emphasize the importance of the intraoperative manometry in the relevance of a concomitant antireflux procedure.