The case for free space

This article discusses the prospect of free-space optical links (FSOLs) in relation to backhaul applications as well as its technology trend, including the recent development of radio on free-space optical links (RoFSOLs). Here, we consider how FSOLs act as useful transport media, focusing on practical experience in mobile backhaul networks. We refer to studies on FSOL conducted by the Internat ional Telecommunications Union (ITU) from the viewpoint of the possible exploitation of the frequency bands above 3,000 GHz, which are outside the scope of the current Radio Regulations. As optical technologies are becoming more advanced, FSOL applications have been considered as a potential medium to provide short-range links using simple and compact equipment. Free-space transmission has advantages such as rapid deployment and relocation; however, it has to be operated under limited link lengths due to the propagation impairments.     

Satellite-based estimation of surface vapor pressure deficits using MODIS land surface temperature data

Vapor Pressure Deficit (VPD) is a principle mediator of global terrestrial CO₂ uptake and water vapor loss through plant stomata. As such, methods to estimate VPD accurately and efficiently are critical for ecosystem and climate modeling efforts. Based on prior work relating energy partitioning, remotely sensed land surface temperature (LST), and VPD, we developed simple linear models to predict VPD using saturated vapor pressure calculated from MODIS LST at a number of different temporal and spatial resolutions. We developed and assessed the LST-VPD models using three data sets: (1) instantaneous and daytime average ground-based VPD and radiometric temperature from the Soil Moisture Experiments in 2002 (SMEX02); (2) daytime average VPD from AmeriFlux eddy covariance flux tower observations; and (3) estimated daytime average VPD from Global Surface Summary of Day (GSSD) observations. We estimated model parameters for VPD estimation both regionally (MOD11 A2) and globally (MOD11 C2) with RMSE values ranging from .32 to .38 kPa. VPD was overestimated along coastlines and underestimated in arid regions with low vegetation cover. Also, residuals were larger with higher VPDs because of the non-linear function of saturation vapor pressure with LST. Linear relationships were seen at multiple scales and appear useful for estimation purposes within a range of 0 to 2.5 kPa.     

High performance of electroless-plated platinum electrode for electrochemical hydrogen pumps using strontium-zirconate-based proton conductors

The performance of an electroless-plated platinum electrode for electrochemical hydrogen pumps was investigated using SrZr_0.9Y_0.1O_3−α (10Y-SZO) and SrZr_0.5Ce_0.4Y_0.1O_3−α (10Y-SZCO) as proton-conducting electrolytes. The plated electrodes using these electrolytes showed quite low overpotentials, resulting in high performance of the hydrogen pumps. The high electrode performance is interpreted from the viewpoint of the three-phase boundary (TPB) length: the plated electrode has a larger TPB length per unit area than that of the pasted electrode. The difference between 10Y-SZO and 10Y-SZCO in ability to match with platinum electrodes is also discussed, and the possibility that the TPB width of 10Y-SZCO with platinum is larger than that of 10Y-SZO is suggested.     

Long-term survivors in biliary atresia--findings for a 20-year survival group

Recently, there has been remarkable increase in the survival rate in cases of biliary atresia (BA). However, long-term survivors are as yet a small population. Of the total of 152 patients undergoing surgery for BA during the period from 1969 to 1995 in our institution, 39 of them were operated on more than 20 years ago with follow up for all but one of these, who can no longer be accounted for. Six are still alive, 1 male, and 5 females, two cases being of type I BA, and the other 4 of type III and 1 is unaccounted for. The prognosis of these individuals was clinically evaluated. At the present time, none of them is receiving hospital care, but 3 have experienced sequelae. Two patients required partial splenic embolization (PSE), endoscopic infusion sclerotherapy (EIS), and/or gastroesophageal decongestion and splenectomy (Hassab's operation) (Hassab 1967) for hypersplenism and/or portal hypertension. The other has needed hospital care for recurrent cholangitis. Laboratory investigations revealed a serum total bilirubin (TB) of less than 1.0 mg/100 ml in 3 of the 5 patients for which samples could be obtained, between 1.0 and 2.0 mg/100 ml in 1, and in excess of this in the remaining case. The 1-alanine 2 oxoglutarate aminotransferase (ALT) level was within the normal range in only 1, and was mildly to moderately elevated in 4. The white blood cell count (WBC) was less than 3,000/microliter and the platelet count was less than 10 x 10(4)/microliter in 1, and within the normal ranges in the other 4 patients. The results thus indicate that occult and progressive liver damage may occur in long-term survivors of BA.     

Characteristics of passivity of extremely corrosion-resistant amorphous iron alloys

The amorphous FeCrPC alloy was compared with the crystallized alloy having the same composition in potentiodynamic polarization curves and with an 18Cr8Ni stainless steel in current decay after abrading the specimens under anodic polarization. Through these results along with the previous ESCA study, the extremely high corrosion-rseistance of the amorphous iron alloys containing 8 at.% or more chromium has been interpreted in terms of the rapid formation of thick, uniform, highly corrosion-resistant passive film due to the characteristics of the amorphous alloys.     

The effect of probucol on oxidized cholesterol disposition in hyperlipidaemic patients

Hardly any part of the legal regulations on absenteeism and incapacity for work has remained unchanged since 1993 in the Netherlands. The system is becoming increasingly complicated. The essence of the changes is that employers' responsibility has greatly increased. The new regulations mean a transition from industrial health care to Factories Act services and from the industrial insurance board to implementing organs. The legislator emphasizes the evaluation of what people with health disorders are still able to do. Prevention of absenteeism/ incapacity for work and reintegration are given great attention. Treating physicians should not let the complicated regulations keep them from fulfilling their tasks concerning sick employees, since it is increasingly in the patient's interest that chronicity be prevented whenever possible.     

Activation of c-Jun N-terminal kinase during ischemia and reperfusion in mouse liver

We have generated a mouse model for hepatic ischemia in which surgical subcutaneous transposition of the spleen allows hepatic ischemia to be applied without affecting other tissues. Using this mouse model we investigated the relationship between the length of ischemic periods in the liver and subsequent liver function; furthermore, we assayed the activation of c-Jun N-terminal kinase (JNK) during ischemia and reperfusion. Although prior to this study only the activated form of JNK was known to be translocated to the nucleus, we found that JNK translocates to the nucleus during ischemia without activation and is then activated during reperfusion. These results suggest a novel mechanism of JNK activation.